We previously found that ribosomal protein L9 (RPL9) is a novel advanced glycation end product (AGE)-binding protein that can decrease pro-inflammatory TNF-α expression stimulated by lipopolysaccharide (LPS) plus high-mobility group box 1 (HMGB1), suggesting that RPL9 has a role in regulating LPS+HMGB1-stimulated inflammatory reactions. Among the various ribosomal proteins, it was found that RPS5 reproduced the regulatory activity of RPL9 on LPS+HMGB1-stimulated TNF-α expression in macrophage-like RAW264.7 cells. RPL9 and RPS5 share a common feature as cationic proteins. Polylysine, a cationic polypeptide, and a synthetic peptide of the cationic region from RPL9 also exhibited reducing activity on LPS+HMGB1-induced TNF-α expression. By pull-down assay, RPL9 and RPS5 were confirmed to interact with AGEs. When AGEs coexisted with LPS, HMGB1, plus RPL9 or RPS5, the reducing effect of TNF-α expression by these cationic ribosomal proteins was shown to be abrogated. The results suggest that cationic ribosomal proteins have a regulatory role in the pro-inflammatory response induced by LPS+HMGB1, and in the pathophysiological condition of accumulating AGEs, this regulatory effect is abolished, which exacerbates inflammation.

Advanced glycation end products (AGEs) are a heterogeneous group of compounds that are non-enzymatically produced by reactions between carbonyl compounds and proteins. Many types of AGEs are produced according to the type or concentration of the reacting carbonyl compound. We have previously demonstrated that a glycolaldehyde-derived AGE suppresses stimulator of interferon gene (STING)/TANK-binding kinase 1 (TBK1)/interferon regulatory transcription factor 3 (IRF3), which is a component of the innate immune system. In this report, we investigated the effects of AGEs prepared by several carbonyl compounds on STING/TBK1/IRF3 signaling. AGEs used in the present study were numbered based on the carbonyl compound type: AGE1, derived from glucose; AGE2, derived from glyceraldehyde; AGE3, derived from glycolaldehyde; AGE4, derived from methylglyoxal; and AGE5, derived from glyoxal. AGEs derived from aldehyde (AGE2 and AGE3) and dicarbonyl compounds (AGE4 and AGE5) suppressed cyclic GMP-AMP (cGAMP)-induced activation of STING/TBK1/IRF3 signaling, with different suppression efficiencies observed. Lysine modification by carbonyl compounds was related to the efficiency of the suppressive effect on STING/TBK1/IRF3 signaling. Among the AGEs used, only AGE1 enhanced cGAMP-induced activation of STING/TBK1/IRF3 signaling. Enhancing the modulation of STING/TBK1/IRF3 signaling by AGE1 was mediated by toll-like receptor 4. These results indicated that modulation of STING/TBK1/IRF3 signaling by prepared AGEs is dependent on the type and concentration of the carbonyl compound present. Modulating STING/TBK1/IRF3 signaling by AGEs may involve modification of lysine residues in proteins.

BACKGROUND: Advanced glycation end products (AGEs) are heterogeneous proinflammatory molecules produced by a non-enzymatic glycation reaction between reducing sugars (and their metabolites) and biomolecules with amino groups, such as proteins. Although increases in and the accumulation of AGEs have been implicated in the onset and exacerbation of lifestyle- or age-related diseases, including diabetes, their physiological functions have not yet been elucidated in detail. METHODS AND RESULTS: The present study investigated the cellular responses of the macrophage cell line RAW264.7 stimulated by glycolaldehyde-derived AGEs (Glycol-AGEs) known as representative toxic AGEs. The results obtained showed that Glycol-AGEs significantly promoted the proliferation of RAW264.7 cells at a low concentration range (1-10 µg/mL) in a concentration-dependent manner. On the other hand, neither TNF-α production nor cytotoxicity were induced by the same concentrations of Glycol-AGEs. The increases observed in cell proliferation by low concentrations of Glycol-AGEs were also detected in receptor triple knockout (RAGE-TLR4-TLR2 KO) cells as well as in wild-type cells. Increases in cell proliferation were not affected by various kinase inhibitors, including MAP kinase inhibitors, but were significantly suppressed by JAK2 and STAT5 inhibitors. In addition, the expression of some cell cycle-related genes was up-regulated by the stimulation with Glycol-AGEs. CONCLUSIONS: These results suggest a novel physiological role for AGEs in the promotion of cell proliferation via the JAK-STAT pathway.

Histamine is a well-known inflammatory mediator, but how histamine induces angiogenesis remains poorly understood. In the present study, we demonstrated a dose-dependent dynamic tube formation in the human endothelial cell line EA.hy926 in the presence of histamine that was completely blocked by histamine H1 receptor (H1R) and protein kinase C (PKC) inhibitors. However, histamine H2, H3, and H4 receptor inhibitors did not inhibit tube formation, suggesting that H1R-PKC signaling is involved in histamine-induced tube formation. Moreover, we found an H1-specific induction of vascular endothelial growth factor (VEGF) expression. Inhibition of VEGF receptor 2 (VEGFR2) suppressed the histamine-induced tube formation, indicating that VEGF is downstream of histamine signaling. Additionally, we demonstrated that histamine stimulation induces the expression of critical regulators of angiogenesis such as matrix metalloproteinase (MMP)-9 and MMP-14 metalloproteases, as histamine-induced tube formation is blocked by MMP inhibitors. In summary, our study indicates that histamine can activate the H1R in human endothelial cells and thereby promote tube formation through the PKC, MMP, and VEGF signaling pathways.

AIMS: We have previously reported that advanced glycation end products derived from incubation of albumin with glycolaldehyde (glycol-AGE), lead to suppression of the toll-like receptor 4 (TLR4) signaling response to lipopolysaccharide. Glycol-AGE-induced suppression of TLR4 signaling is involved in the downregulation of CD14, which is an adaptor protein necessary for transferring lipopolysaccharide to TLR4. Therefore, glycol-AGEs impair the innate immune response through suppression of the upstream process in TLR4 signaling. However, the effect of glycol-AGEs on intracellular signaling related to the innate immune response remains unclear. This study aimed to examined the effect of glycol-AGEs on stimulator of interferon gene (STING) signaling in macrophages. MAIN METHODS: In differentiated THP-1 cells, which are a human monocytic leukemia cell line, cyclic GMP-AMP (cGAMP) transfection was used to activate STING signaling. The phosphorylation levels of TANK-binding kinase 1 (TBK1)/interferon regulatory transcription factor 3 (IRF3) were evaluated by western blot analysis. Downstream cytokine levels were evaluated by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assays. KEY FINDINGS: Glycol-AGEs suppressed cGAMP-induced phosphorylation of TBK1 and IRF3, as well as the production of cytokines regulated by IRF3. There was no effect of glycol-AGEs on the efficacy of cGAMP transfection. Treatment of a neutralizing antibody against CD36 prevented cGAMP-induced phosphorylation of TBK1 and IRF3, and also upregulation of interferon-β and C-X-C motif chemokine ligand 10 in glycol-AGE-treated cells. SIGNIFICANCE: Glycol-AGEs negatively regulate cGAMP-induced activation of STING/TBK1/IRF3 signaling via CD36. Our findings suggest that glycol-AGEs lead to impairment of the innate immune response by suppressing intracellular signaling.

BACKGROUND: Methylglyoxal (MGO) is a known toxic byproduct of glycolysis, with MGO-induced cytotoxicity believed to contribute to the pathogenesis of several diseases. Glyoxalase I (GLO1) is a key enzyme for eliminating MGO in mammalian cells, therefore, compounds affecting GLO1 activity are potential therapeutic agents for MGO-induced disorders. Previously, we found nordihydroguaiaretic acid (NDGA) as a potent GLO1 inhibitor. METHODS: The inhibitory characteristics of NDGA were determined spectrophotometrically with recombinant GLO1. NDGA-induced growth-inhibition and accumulation of MGO-derived advanced glycation end products (AGEs) were examined in EA.hy926 cells. RESULTS: NDGA showed significant inhibition of GLO1 enzymatic activity in a dose-dependent manner. Its Ki value was estimated to be 146-fold lower than that of myricetin, a known GLO1 inhibitor. The co-addition of MGO with NDGA to the cells resulted in significant growth inhibition, suggesting that MGO accumulation, sufficient to affect cell growth, was caused by NDGA inhibiting GLO1. These findings were supported by the observations that the addition of aminoguanidine, a typical MGO scavenger, significantly reversed cell-growth inhibition by co-addition of MGO with NDGA, and that an increase in intracellular MGO-derived AGEs was observed during incubation with the co-addition of MGO with NDGA. CONCLUSION: NDGA was found to be a novel and potent inhibitor of GLO1. The co-addition of NDGA with MGO to the cells resulted in increased intracellular MGO accumulation followed by enhanced cell-growth inhibition.

BACKGROUND: We previously reported that advanced glycation endproducts (AGEs) increase the proinflammatory activity of high mobility group box-1 (HMGB1), a representative damage-associated molecular pattern molecule (DAMP), through their direct interaction. This suggested that AGEs activate other DAMPs and led us to search for novel DAMPs capable of interacting with AGEs. METHODS AND RESULTS: The chromatographic analysis using AGE-immobilized gel revealed the ribosomal protein family to be a factor with binding activity to AGEs. Ribosomal protein L9 (RPL9), a member of the ribosomal protein family, was found in the centrifugal supernatant of ruptured cells and in the serum of lipopolysaccharide (LPS)-stimulated sepsis model mice, exhibiting similar characteristic properties to HMGB1. Although HMGB1 potentiated LPS-stimulated TNF-α expression in macrophage-like RAW264.7 cells, RPL9 hardly exhibited this activity. Of note, RPL9 significantly suppressed the potentiated mRNA expression and protein production of TNF-α by HMGB1 plus LPS stimulation, suggesting its regulatory roles in DAMP-induced proinflammatory activity. Based on the differential scanning fluorimetric analysis, the direct interaction between RPL9 and HMGB1 may play a role in the suppressive effects of RPL9. CONCLUSIONS: This study suggested that RPL9 is a novel type of DAMP with a regulatory role in the proinflammatory response and provided insight into the pathophysiology of inflammatory diseases.

Toxic advanced glycation end products (toxic AGEs) derived from glycolaldehyde (AGE3) have been implicated in the development of diabetic vascular complications such as retinopathy characterised by excessive angiogenesis. Different receptor types, such as receptor for AGEs (RAGE), Toll like receptor-4 and scavenger receptors, are expressed in endothelial cells and contribute to AGE-elicited alteration of cell function. In the present study, we examined the involvement of AGE-related receptors on AGE-induced angiogenesis in endothelial cells. The effects of pharmacological inhibitors or receptor neutralizing antibodies on AGE3-induced tube formation were investigated using the in vitro Matrigel tube formation assay in b.End5 cells (mouse endothelial cells). AGE3-induced signalling pathways and receptor expression changes were analysed by Western blot analysis and flow cytometry, respectively. Both FPS-ZM1, a RAGE inhibitor, and fucoidan, a ligand for scavenger receptors, suppressed AGE3-induced tube formation. Cocktails of neutralizing antibodies against the scavenger receptors CD36, CD163 and LOX-1 prevented AGE3-induced tube formation. AGE3 activated mTOR signalling, resulting in facilitation of tube formation. Activation of the AGE-RAGE pathway also led to the upregulation of scavenger receptors. Taken together, our findings suggest that the scavenger receptors CD36, CD163 and LOX-1 in conjunction with the RAGE receptor work together to mediate toxic AGE-induced facilitation of angiogenesis.

Idiopathic pulmonary fibrosis (IPF) is the most common and most deadly form of interstitial lung disease. Osteopontin (OPN), a matricellular protein with proinflammatory and profibrotic properties, plays a major role in several fibrotic diseases, including IPF; OPN is highly upregulated in patients' lung samples. In this study, we knocked down OPN in a bleomycin (BLM)-induced pulmonary fibrosis (PF) mouse model using small interfering RNA (siRNA) to determine whether the use of OPN siRNA is an effective therapeutic strategy for IPF. We found that fibrosing areas were significantly smaller in specimens from OPN siRNA-treated mice. The number of alveolar macrophages, neutrophils, and lymphocytes in bronchoalveolar lavage fluid was also reduced in OPN siRNA-treated mice. Regarding the expression of epithelial-mesenchymal transition (EMT)-related proteins, the administration of OPN-siRNA to BLM-treated mice upregulated E-cadherin expression and downregulated vimentin expression. Moreover, in vitro, we incubated the human alveolar adenocarcinoma cell line A549 with transforming growth factor (TGF)-β1 and subsequently transfected the cells with OPN siRNA. We found a significant upregulation of Col1A1, fibronectin, and vimentin after TGF-β1 stimulation in A549 cells. In contrast, a downregulation of Col1A1, fibronectin, and vimentin mRNA levels was observed in TGF-β1-stimulated OPN knockdown A549 cells. Therefore, the downregulation of OPN effectively reduced pulmonary fibrotic and EMT changes both in vitro and in vivo. Altogether, our results indicate that OPN siRNA exerts a protective effect on BLM-induced PF in mice. Our results provide a basis for the development of novel targeted therapeutic strategies for IPF.

Hyperglycaemia provides a suitable environment for infections and the mechanisms of glucose toxicity include the formation of advanced glycation end-products (AGEs), which comprise non-enzymatically glycosylated proteins, lipids, and nucleic acid amino groups. Among AGE-associated phenotypes, glycolaldehyde-derived toxic AGE (AGE-3) is involved in the pathogenesis of diabetic complications. Internalisation of endotoxin by various cell types contributes to innate immune responses against bacterial infection. An endotoxin derived from Gram-negative bacteria, lipopolysaccharide (LPS), was reported to enhance its own uptake by RAW264.7 mouse macrophage-like cells, and an LPS binding protein, CD14, was involved in the LPS uptake. The LPS uptake induced the activation of RAW264.7 leading to the production of chemokine CXC motif ligand (CXCL) 10, which promotes T helper cell type 1 responses. Previously, we reported that AGE-3 was internalised into RAW264.7 cells through scavenger receptor-1 Class A. We hypothesized that AGEs uptake interrupt LPS uptake and impair innate immune response to LPS in RAW264.7 cells. In the present study, we found that AGE-3 attenuated CD14 expression, LPS uptake, and CXCL10 production, which was concentration-dependent, whereas LPS did not affect AGE uptake. AGEs were reported to stimulate the receptor for AGEs and Toll-like receptor 4, which cause inflammatory reactions. We found that inhibitors for RAGE, but not Toll-like receptor 4, restored the AGE-induced suppression of CD14 expression, LPS uptake, and CXCL10 production. These results indicate that the receptor for the AGE-initiated pathway partially impairs the immune response in diabetes patients.

Previously, we found that advanced glycation endproducts (AGEs) directly interact with tumor necrosis factor (TNF)-like weak inducer of apoptosis, a cytokine that controls inflammation, and that this interaction inhibited its action. This finding raised the novel possibility that AGEs alter the function of other cytokines through direct interaction. To investigate this possibility, we performed comprehensive screening for candidates that interacted with AGEs using protein array analysis. The array analysis revealed that high mobility group box-1 (HMGB1) had a markedly high affinity for AGEs. HMGB1 is a representative proinflammatory damage-associated molecular pattern molecule, and is reported to interact with lipopolysaccharide (LPS) directly to exert its inflammatory function. When LPS, HMGB1, and AGEs were mixed, the mobility of HMGB1 had shifted significantly in native PAGE, suggesting that these three molecules formed a triplet complex. The addition of AGEs to the LPS-HMGB1 mixture synergistically potentiated LPS-HMGB1-stimulated TNF-alpha mRNA expression in macrophage-like RAW264.7 cells. In addition, using receptor knockout clones, the increased proinflammatory response by LPS-HMGB1-AGEs complex was demonstrated to be mediated via Toll-like receptor 4 and receptor for AGEs. Taken together, this study suggested that AGEs carry out their pathophysiological roles by potentiating the LPS-HMGB1-stimulated proinflammatory response through direct interactions.

High-mobility group box-1 (HMGB1) protein has been postulated to play a pathogenic role in severe sepsis. Histidine-rich glycoprotein (HRG), a 75 kDa plasma protein, was demonstrated to improve the survival rate of septic mice through the regulation of neutrophils and endothelium barrier function. As the relationship of HRG and HMGB1 remains poorly understood, we investigated the effects of HRG on HMGB1-mediated pathway in endothelial cells, focusing on the involvement of specific receptors for HRG. HRG potently inhibited the HMGB1 mobilization and effectively suppressed rHMGB1-induced inflammatory responses and expression of all three HMGB1 receptors in endothelial cells. Moreover, we first clarified that these protective effects of HRG on endothelial cells were mediated through C-type lectin domain family 1 member A (CLEC-1A) receptor. Thus, current study elucidates protective effects of HRG on vascular endothelial cells through inhibition of HMGB1-mediated pathways may contribute to the therapeutic effects of HRG on severe sepsis.

Background: Cerebral small vessel disease (CSVD) is associated with future stroke. Although pathological alteration in small vessels of patients with CSVD can be detected by neuroimaging, diagnosis of CSVD is delayed because it is an asymptomatic disease. The stroke-prone spontaneously hypertensive rat (SHRSP) show similar pathological features to human CSVD and develop stroke-related symptoms with advancing age.Objective: We investigated the time course of haematological parameters in Wistar rats and SHRSP.Material and Methods: Blood cells were analysed using an automated haematological analyser.Results: SHRSP develop stroke-related symptoms including onset of neurological symptoms, decreased body weight and blood brain barrier leakage between 12 and 14 weeks of age. Lymphocyte counts were gradually decreased at 3 weeks before development of stoke-related symptoms and then were further decreased after the development of stroke-related symptoms. The both mean platelet volume and large platelet ratio gradually increased at 3 weeks before the development of stoke-related symptoms. However, although SHRSP showed more microcytic red cells than Wistar rats, the trajectories of change in erythrocyte-related parameters were similar between Wistar rats and SHRSP.Conclusion: Our pilot study suggests that alterations of lymphocyte count and platelet volume predictive indicators for asymptomatic CSVD and symptomatic stroke in SHRSP.

Advanced glycation end products (AGEs) are considered to be related to the pathogenesis of some inflammatory diseases. AGEs were reported to stimulate the receptor for AGEs (RAGE), which causes inflammatory reactions. However, recently, toll-like receptors (TLRs), in addition to RAGE, have been reported to be related to AGE-mediated cellular responses, and it remains unclear which receptor is responsible for AGE recognition. To reveal the role of pattern-recognition receptors, including TLRs and/or RAGE, in AGE-mediated cellular responses, we generated macrophage-like RAW264.7 knockout (KO) cells lacking these receptors by genome editing using the CRISPR/Cas9 system and assessed AGE-stimulated changes in these cells. Comparison of the established clones suggested that RAGE partially affects the expression of TLRs. In the KO clone lacking TLR4 and TLR2, AGE-stimulated tumor necrosis factor alpha (TNF-α) expression and phosphorylation of IκBα, p38, and extracellular signal-regulated kinase (ERK) were significantly attenuated, suggesting that AGE-mediated responses are largely dependent on TLRs. On the other hand, on comparison of the AGE-stimulated responses between the KO clone lacking TLR4 and TLR2, and the clone lacking TLR4, TLR2, and RAGE, RAGE played little role in AGE-stimulated TNF-α transcription and ERK phosphorylation. Taken together, this study suggested that AGE-stimulated inflammatory responses occur mainly through TLRs rather than RAGE.

Advanced glycation end-products, especially toxic advanced glycation end-products derived from glyceraldehyde (advanced glycation end-product-2) and glycolaldehyde (advanced glycation end-product-3), are biologically reactive compounds associated with diabetic complications. We previously demonstrated that toxic advanced glycation end-products were internalised into macrophage-like RAW264.7 cells through scavenger receptor-1 class A (CD204). Toxic advanced glycation end-product uptake was inhibited by fucoidan, a sulphated polysaccharide and antagonistic ligand for scavenger receptors, suggesting that sulphated polysaccharides are emerging candidates for treatment of advanced glycation end-product–related diseases. In this study, we compared the effects of six types of sulphated and non-sulphated polysaccharides on toxic advanced glycation end-product uptake in RAW264.7 cells. Fucoidan, carrageenan and dextran sulphate attenuated toxic advanced glycation end-product uptake. Fucoidan and carrageenan inhibited advanced glycation end-product-2–induced upregulation of SR-A, while advanced glycation end-product-3–induced upregulation of scavenger receptor-1 class A was only suppressed by fucoidan. Dextran sulphate did not affect scavenger receptor-1 class A levels in toxic advanced glycation end-product–treated cells. Chondroitin sulphate, heparin and hyaluronic acid failed to attenuate toxic advanced glycation end-product uptake. Heparin and hyaluronic acid had no effect on scavenger receptor-1 class A levels, while chondroitin sulphate inhibited advanced glycation end-product-3–induced upregulation of scavenger receptor-1 class A. Taken together, fucoidan and carrageenan, but not the other sulphated polysaccharides examined, had inhibitory activities on toxic advanced glycation end-product uptake and toxic advanced glycation end-product–induced upregulation of scavenger receptor-1 class A, possibly because of structural differences among sulphated polysaccharides.

BACKGROUND AND PURPOSE: Microvascular barrier breakdown is a hallmark of sepsis that is associated with sepsis-induced multiorgan failure. Histidine-rich glycoprotein (HRG) is a 75-kDa plasma protein that was demonstrated to improve the survival of septic mice through regulation of cell shape, spontaneous ROS production in neutrophils, and adhesion of neutrophils to vascular endothelial cells. We investigated HRG's role in the LPS/TNF-α-induced barrier dysfunction of endothelial cells in vitro and in vivo and the possible mechanism, to clarify the definitive roles of HRG in sepsis. EXPERIMENTAL APPROACH: EA.hy 926 endothelial cells were pretreated with HRG or human serum albumin before stimulation with LPS/TNF-α. A variety of biochemical assays were applied to explore the underlying molecular mechanisms on how HRG protected the barrier function of vascular endothelium. KEY RESULTS: Immunostaining results showed that HRG maintains the endothelial monolayer integrity by inhibiting cytoskeleton reorganization, losses of VE-cadherin and β-catenin, focal adhesion kinase degradation, and cell detachment induced by LPS/TNF-α. HRG also inhibited the cytokine secretion from endothelial cells induced by LPS/TNF-α, which was associated with reduced NF-κB activation. Moreover, HRG effectively prevented the LPS/TNF-α-induced increase in capillary permeability in vitro and in vivo. Finally, Western blot results demonstrated that HRG prevented the phosphorylation of MAPK family and RhoA activation, which are involved mainly in the regulation of cytoskeleton reorganization and barrier permeability. CONCLUSIONS AND IMPLICATIONS: Taken together, our results demonstrate that HRG has protective effects on vascular barrier function in vitro and in vivo, which may be due to the inhibition of MAPK family and Rho activation.

High mobility group box-1 (HMGB1), a representative damage associated-molecular pattern (DAMP), has been reported to be involved in many inflammatory diseases. Several drugs are thought to have potential to control the translocation and secretion of HMGB1, or to neutralize extracellular HMGB1 by binding to it. One of these drugs, anti-HMGB1 monoclonal antibody (mAb), is highly specific for HMGB1 and has been shown to be effective for the treatment of a wide range of CNS diseases when modeled in animals, including stroke, traumatic brain injury, Parkinson's disease, epilepsy and Alzheimer's disease. Thus, anti-HMGB1 mAb not only is useful for target validation but also has extensive potential for the treatment of the above-mentioned diseases. In this review, we summarize existing knowledge on the effects of anti-HMGB1 mAb on CNS and PNS diseases, the common features of translocation and secretion of HMGB1 and the functional roles of HMGB1 in these diseases. The existing literature suggests that anti-HMGB1 mAb therapy would be effective for a wide range of CNS and PNS diseases.

Previously, we found that endogenously produced pro-inflammatory molecules, advanced glycation end products (AGEs), interact with tumor necrosis factor-like weak inducer of apoptosis (TWEAK), and attenuate its immunomodulatory function. In the present study, to elucidate the mechanism by which AGEs attenuate TWEAK function, we searched for regions responsible for TWEAK-AGE interaction using TWEAK deletion mutants. Pull-down assays with the TWEAK mutants and AGEs revealed that the C-terminal half of TWEAK, which is the region essential for receptor stimulation, was required for this interaction. On the other hand, the N-terminal deletion mutants did not exhibit a significant decrease in AGE binding. Moreover, a moderate decrease in the AGE binding by double-deletion in quartered C-terminal half regions and a substantial decrease by triple-deletion in this region were observed. In addition, full-length TWEAK stimulated IL-8 gene expression in endothelial EA.hy.926 cells, whereas the triple-deletion mutant lost much of this activity, suggesting that the TWEAK-AGE interaction sites overlap with the region needed to exert normal function of TWEAK. Our present findings may help to elucidate the pathophysiological roles of the TWEAK-AGE interaction for prevention and treatment of AGE-related inflammatory diseases.

BACKGROUND: High mobility group box 1 (HMGB1) protein plays a key role in triggering inflammatory responses in many diseases. Our previous study showed that HMGB1 is found upstream of secondary damage in traumatic brain injury (TBI). We found that anti-HMGB1 monoclonal antibody (mAb) effectively decreased acute brain damage, including the disruption of the blood-brain barrier, brain edema, and neurologic dysfunction. This effect of anti-HMGB1 mAb lasts for at least 1 week. In this study, we explored subacute effects of anti-HMGB1 mAb after TBI. METHODS: TBI was induced in rats by fluid percussion. Anti-HMGB1 mAb or control mAb was given intravenously after TBI. Histochemical staining, plasma levels of HMGB1, motor activity and memory, and video electroencephalography monitoring were evaluated 2 weeks after fluid percussion injury. RESULTS: Anti-HMGB1 mAb remarkably attenuated accumulation of activated microglia in the rat cortex in the ipsilateral hemisphere after TBI. Anti-HMGB1 mAb also prevented neuronal death in the hippocampus in the ipsilateral hemisphere after TBI. Treatment of rats with anti-HMGB1 mAb inhibited HMGB1 translocation and suppressed impairment of motor function. The beneficial effects of anti-HMGB1 mAb on motor and cognitive function persisted for 14 days after injury. Treatment with anti-HMGB1 mAb also had positive effects on electroencephalography activity. CONCLUSIONS: The beneficial effects of anti-HMGB1 mAb continued during the subacute postinjury phase, suggesting that anti-HMGB1 mAb may prevent cognitive dysfunction after TBI.

Objectives Severe acute pancreatitis is a highly lethal disease caused by systemic inflammatory response syndrome, leading to multiple organ failure. We recently showed that histidine-rich glycoprotein (HRG) supplemental therapy ameliorated septic acute respiratory distress syndrome due to unnecessary neutrophil activation and immunothrombosis formation. Here, we evaluated the effect of HRG on lung inflammation followed by pancreatitis in a severe acute pancreatitis mouse model.Methods Mice received intraperitoneal injections of cerulein 7 times (100 g/kg each) at 1-hour intervals to induce acute pancreatitis. Immediately after the first cerulein injection, phosphate-buffered saline, human serum albumin (20 mg/kg), or HRG (20 mg/kg) was intravenously injected. One hour after the last cerulein injection, phosphate-buffered saline or lipopolysaccharide (5 mg/kg) was intravenously injected into the tail vein. We evaluated lung inflammatory level after pancreatitis.Results We observed significantly decreased plasma HRG levels in an acute pancreatitis mouse model. Histidine-rich glycoprotein treatment inhibited lung edema and the accumulation of neutrophil in severe acute pancreatitis, but HRG did not directly affect pancreatitis. Moreover, HRG suppressed tumor necrosis factor , inducible nitric oxide synthase, interleukin 6, and neutrophil elastase mRNA expression and myeloperoxidase activity in the lung.Conclusions These data suggested that HRG ameliorated lung inflammation secondary to pancreatitis.

Together with residual host neurons, transplanted neural stem cell (NSC)-derived neurons play a critical role in reconstructing disrupted neural circuits after spinal cord injury (SCI). Since a large number of tracts are disrupted and the majority of host neurons die around the lesion site as the damage spreads, minimizing this spreading and preserving the lesion site are important for attaining further improvements in reconstruction. High mobility group box-1 (HMGB1) is a damage-associated molecular pattern protein that triggers sterile inflammation after tissue injury. In the ischemic and injured brain, neutralization of HMGB1 with a specific antibody reportedly stabilizes the blood-brain barrier, suppresses inflammatory cytokine expression, and improves functional recovery. Using a SCI model mouse, we here developed a combinatorial treatment for SCI: administering anti-HMGB1 antibody prior to transplantation of NSCs derived from human induced pluripotent stem cells (hiPSC-NSCs) yielded a dramatic improvement in locomotion recovery after SCI. Even anti-HMGB1 antibody treatment alone alleviated blood-spinal cord barrier disruption and edema formation, and increased the number of neurites from spared axons and the survival of host neurons, resulting in functional recovery. However, this recovery was greatly enhanced by the subsequent hiPSC-NSC transplantation, reaching an extent that has never before been reported. We also found that this improved recovery was directly associated with connections established between surviving host neurons and transplant-derived neurons. Taken together, our results highlight combinatorial treatment with anti-HMGB1 antibody and hiPSC-NSC transplantation as a promising novel therapy for SCI. Stem Cells 2018;36:737-750.

Advanced glycation end-products (AGEs), which comprise non-enzymatically glycosylated proteins, lipids, and nucleic acid amino groups, play an important role in several diseases and aging processes including angiopathy, renal failure, diabetic complications, and neurodegenerative diseases. Among AGE-associated phenotypes, toxic AGEs, glyceraldehyde-derived AGE-2, and glycolaldehyde-derived AGE-3 are involved in the pathogenesis of diabetic complications. In addition, macrophages are reported to remove extracellular AGEs from tissues via scavenger receptors, leading to the progression of atherosclerosis. In the present study, we found that AGE-2 and AGE-3 enhanced their own endocytic uptake by RAW264.7 mouse macrophage-like cells in a concentration-dependent manner. Furthermore, we demonstrated, for the first time, the morphology of phagocytic macrophages and the endocytosis of AGE particles. The toxic AGEs induced the expression of a scavenger receptor, CD204/scavenger receptors-1 class A (SR-A). Notably, an antibody against CD204 significantly prevented toxic AGE uptake. Moreover, an SR-A antagonistic ligand, fucoidan, also attenuated the AGE-2- and AGE-3-evoked uptake in a concentration-dependent manner. These results indicated that SR-A stimulation, at least in part, plays a role in AGE uptake.

M2 macrophage (Mφ) promotes pathologic angiogenesis through a release of pro-angiogenic mediators or the direct cell-cell interaction with endothelium in the micromilieu of several chronic inflammatory diseases, including rheumatoid arthritis and cancer, where interleukin (IL)-18 also contributes to excessive angiogenesis. However, the detailed mechanism remains unclear. The aim of this study is to investigate the mechanism by which M2 Mφs in the micromilieu containing IL-18 induce excessive angiogenesis in the in vitro experimental model using mouse Mφ-like cell line, RAW264.7 cells, and mouse endothelial cell line, b.End5 cells. We discovered that IL-18 acts synergistically with IL-10 to amplify the production of Mφ-derived mediators like osteopontin (OPN) and thrombin, yielding thrombin-cleaved form of OPN generation, which acts through integrins α4/α9, thereby augmenting M2 polarization of Mφ with characteristics of increasing surface CD163 expression in association with morphological alteration. Furthermore, the results of visualizing temporal behavior and morphological alteration of Mφs during angiogenesis demonstrated that M2-like Mφs induced excessive angiogenesis through the direct cell-cell interaction with endothelial cells, possibly mediated by CD163.

Advanced glycation end products (AGEs) are formed from the non-enzymatic glycation reaction of reducing sugars or their metabolites with the free amino groups of several biomolecules and are known to play pathophysiological roles in various inflammatory diseases. In an earlier study, it was suggested that tumor necrosis factor-like weak inducer of apoptosis (TWEAK) has a unique role to regulate the tumor necrosis factor α (TNFα)-induced inflammatory response. In this study, we investigated the effect of the AGEs-TWEAK interaction on proinflammatory signaling responses in endothelial cells and the influence of AGEs on the cellular function of TWEAK in the inflammatory process. The effect of AGEs on the TWEAK/TNFα-induced gene expression of interleukin-8 (IL-8) was determined by real-time RT-PCR in endothelial-like EA.hy.926 cells. The pull-down assay was performed using recombinant His-tagged TWEAK and AGEs. The NF-κB activation was analyzed by Western blotting with canonical and non-canonical pathway-specific antibodies. AGEs dose-dependently inhibited TWEAK-induced IL-8 gene expression, whereas AGEs themselves had almost no effect on IL-8 expression. AGEs were found to bind directly to TWEAK in the pull-down assay. TNFα-induced IL-8 production and canonical NF-κB activation were suppressed by TWEAK pretreatment, whereas TWEAK-induced non-canonical NF-κB activation was enhanced by pretreatment. These effects induced by TWEAK pretreatment were abolished by the co-addition of AGEs. Our findings suggest that AGEs attenuate the function of TWEAK to regulate the TNFα-induced inflammatory responses, which provide important clues for understanding the significance of the AGEs-TWEAK interaction in inflammatory processes.

Advanced glycation end-products (AGEs) are produced by non-enzymatic glycation between protein and reducing sugar such as glucose. Although glyceraldehyde-derived AGEs (Glycer-AGEs), one of the AGEs subspecies, have been reported to be involved in the pathogenesis of various age-relating diseases such as diabetes mellitus or arteriosclerosis, little is known about the pathological and physiological mechanism of AGEs in vivo. In present study, we produced 4 kinds of polyclonal antibodies against AGEs subspecies and investigated the localization of AGEs-modified proteins in rat peripheral tissues, making use of these antibodies. We found that Glycer-AGEs and methylglyoxal-derived AGEs (MGO-AGEs) were present in pancreatic islets of healthy rats, distinguished clearly into the pancreatic α and β cells, respectively. Although streptozotocin-induced diabetic rats suffered from remarkable impairment of pancreatic islets, the localization and deposit levels of the Glycer- and MGO-AGEs were not altered in the remaining α and β cells. Remarkably, the MGO-AGEs in pancreatic β cells were localized into the insulin-secretory granules. These results suggest that the cell-specific localization of AGEs-modified proteins are presence generally in healthy peripheral tissues, involved in physiological intracellular roles, such as a post-translational modulator contributing to the secretory and/or maturational functions of insulin.

Inflammatory processes in brain tissue have been described in human epilepsy of various etiologies and in experimental models of seizures. High mobility group box-1 (HMGB1) is now recognized as representative of damage-associated molecular patterns (DAMPs). In the present study, we focused on whether anti-HMGB1 antibody treatment could relieve status epilepticus- triggered BBB breakdown and inflammation response in addition to the seizure behavior itself. Pilocarpine and methyl-scopolamine were used to establish the acute seizure model. Anti-HMGB1 mAb showed inhibitory effects on leakage of the BBB, and on the HMGB1 translocation induced by pilocarpine. The expression of inflammation-related factors, such as MCP-1, CXCL-1, TLR-4, and IL-6 in hippocampus and cerebral cortex were down-regulated by anti-HMGB1 mAb associated with the number of activated astrocytes, microglial cells as well as the expression of IL-1β. Both hematoxylin & eosin and TUNEL staining showed that the apoptotic cells could be reduced after anti-HMGB1 mAb treatment. The onset and latency of Racine stage five were significantly prolonged in the anti-HMGB1 mAb group. These results suggested that anti-HMGB1 mAb prevented the BBB permeability, reduced HMGB1 translocation while inhibiting the expression of inflammation-related factors, protected against neural cell apoptosis and prolonged Racine stage 5 seizure onset and latency.

Advanced glycation end products (AGEs) are the products of a series of nonenzymatic modifications of proteins by reducing sugars. AGEs play a pivotal role in development of diabetic complications and atherosclerosis. Accumulation of AGEs in a vessel wall may contribute to the development of vascular lesions. Although AGEs have a diverse range of bioactivities, the clearance process of AGEs from the extracellular space, including the incorporation of AGEs into specific cells, subcellular localization, and the fate of AGEs, remains unclear. In the present study, we examined the kinetics of the uptake of AGEs by mouse macrophage J774.1 cells in vitro and characterized the process. We demonstrated that AGEs bound to the surface of the cells and were also incorporated into the cytoplasm. The temperature- and time-dependent uptake of AGEs was saturable with AGE concentration and was inhibited by cytochalasin D but not chlorpromazine. We also observed the granule-like appearance of AGE immunoreactivity in subcellular localizations in macrophages. Higher concentrations of AGEs induced intracellular ROS and 4-HNE, which were associated with activation of the NF-κB pathway and caspase-3. These results suggest that incorporation of AGEs occurred actively by endocytosis in macrophages, leading to apoptosis of these cells through NF-κB activation.

Although delayed cerebral vasospasm (DCV) following subarachnoid hemorrhage (SAH) is closely related to the progression of brain damage, little is known about the molecular mechanism underlying its development. High mobility group box-1 (HMGB1) plays an important role as an initial inflammatory mediator in SAH. In this study, an SAH rat model was employed to evaluate the effects of anti-HMGB1 monoclonal antibody (mAb) on DCV after SAH. A vasoconstriction of the basilar artery (BA) associated with a reduction of nuclear HMGB1 and its translocation in vascular smooth muscle cells were observed in SAH rats, and anti-HMGB1 mAb administration significantly suppressed these effects. Up-regulations of inflammation-related molecules and vasoconstriction-mediating receptors in the BA of SAH rats were inhibited by anti-HMGB1 mAb treatment. Anti-HMGB1 mAb attenuated the enhanced vasocontractile response to thrombin of the isolated BA from SAH rats and prevented activation of cerebrocortical microglia. Moreover, locomotor activity and weight loss recovery were also enhanced by anti-HMGB1 mAb administration. The vasocontractile response of the BA under SAH may be induced by events that are downstream of responses to HMGB1-induced inflammation and inhibited by anti-HMGB1 mAb. Anti-HMGB1 mAb treatment may provide a novel therapeutic strategy for DCV and early brain injury after SAH.

Sepsis is a major cause of death worldwide. We show that a plasma protein histidine-rich glycoprotein (HRG) was decreased significantly in septic mice with cecal ligation and puncture (CLP) and supplementary treatment of septic mice with exogenous HRG improved survival, with strong inhibition of tight attachment of neutrophils to pulmonary vasculatures, subsequent immunothrombosis, DIC state, lung inflammation, hypercytokinemia, and activation of vascular endothelial cells (VECs). In contrast, knockdown of HRG by siRNA exacerbated lethality. Purified human HRG reversibly induced morphological changes in human neutrophils in vitro; induction of spherical shape with reduced microvilli and adhesiveness to VECs. HRG maintained the passage of neutrophils through microcapillaries and abolished production of reactive oxygen species. These results suggested that the supplementary therapy with HRG may provide a novel strategy for the treatment of sepsis through suppression of excessive systemic inflammation and immunothrombosis by keeping circulating neutrophils quiescent and preventing uncontrolled activation of VECs. (C) 2016 The Authors. Published by Elsevier B.V.

Acute respiratory distress syndrome (ARDS) is a severe respiratory failure caused by acute lung inflammation. Recently, the receptor for advanced glycation end-products (RAGE) has attracted attention in the lung inflammatory response. However, the function of soluble form of RAGE (sRAGE), which is composed of an extracellular domain of RAGE, in ARDS remains elusive. Therefore, we investigated the dynamics of pulmonary sRAGE and the effects of exogenous recombinant human sRAGE (rsRAGE) under intratracheal lipopolysaccharide (LPS)-induced lung inflammation. Our result revealed that RAGE was highly expressed on the alveolar type I epithelial cells in the healthy rat lung including sRAGE isoform sized 45 kDa. Under LPS-induced injured lung, the release of sRAGE into the alveolar space was increased, whereas the expression of RAGE was decreased with alveolar disruption. Treatment of the injured lung with rsRAGE significantly suppressed the lung edema, the neutrophils infiltration, the release of high mobility group box-1 (HMGB1), and the expressions of TNF-alpha, IL-1 beta and iNOS. These results suggest that the alveolar release of sRAGE may play a protective role against HMGB1 as well as exogenous pathogenassociated molecular patterns. Supplementary therapy with sRAGE may be an effective therapeutic strategy for ARDS. (C) 2016 The Authors. Production and hosting by Elsevier B.V. on behalf of Japanese Pharmacological Society. This is an open access article under the CC BY-NC-ND license.

High mobility group box protein1 (HMGB1), a ubiquitous chromatin component, is released by necrotic cells, apoptotic cells, and cells in profound distress. HMGB1 plays a critical role as a proinflammatory mediator. HMGB1 represents an important new target for drug development in a variety of inflammatory disorders, including stroke, brain injury, arteriosclerosis, and cancer. The antibodies against HMGB1 and its receptors ar hopeful candidates for immunotherapeutic strategy for treating patients with these diseases. HMGB1 forms immunostimulatory complexes by interaction with cytokines and other endogenous or exogenous factors. The HMGB1-partner molecule complexes can enhance the immune response induced by the ligand alone. The current status of HMGB1 works is summarized and future prospects will be provided in this review.

In the adult hypothalamus and ependymal lining of the third ventricle, tanycytes function as multipotential progenitor cells that enable continuous neurogenesis, suggesting that tanycytes may be able to mediate the restoration of homeostatic function after stroke. Voluntary wheel running has been shown to alter neurochemistry and neuronal function and to increase neurogenesis in rodents. In the present study, we found that voluntary exercise improved the survival rate and energy balance of stroke-prone spontaneously hypertensive rats (SHRSP/Kpo). We also investigated the effect of exercise on the proliferation and differentiation of hypothalamic cells using immunoreactivity for tanycytes and neural markers. The proliferation of elongated cells, which may be the tanycytes, was enhanced in exercising SHRSP compared to sedentary rats before and after stroke. In addition, the proliferation of cells was correlated with the induction of fibroblast growth factor-2 in the subependymal cells of the third ventricle and in the cerebrospinal fluid. Some of the newborn cells of exercising SHRSP showed differentiation into mature neurons after stroke. Our results suggest that voluntary exercise correlates with hypothalamic neurogenesis, leading to recovery of homeostatic functions in the adult brain after stroke.

BACKGROUND: The purpose of this study is to determine the effects of anti-high mobility group box 1 (HMGB1) monoclonal antibody (mAb) on ischemia/reperfusion injury (IRI) and the mode of liver regeneration. METHODS: Rats underwent 70% hepatectomy with IRI caused by clamping the hepatoduodenal ligament for 20 minutes, followed by the administration of anti-HMGB1 mAb immediately before declamping the hepatoduodenal ligament. Five animals were used for each time point. We then evaluated IRI, regeneration parameters and the status of HMGB1 in remnant livers. RESULTS: The anti-HMGB1 mAb significantly ameliorated the degree of IRI in the remnant livers in association with the downregulation of HMGB1 protein. The ratio of Ki67-positive hepatocytes at 48 hours after 70% hepatectomy was significantly improved. Mean hepatocyte size was significantly reduced and cyclin-dependent kinase inhibitor 1 expression was significantly attenuated. CONCLUSIONS: Anti-HMGB1 mAb ameliorated IRI and improved the mode of liver regeneration after IRI followed by 70% hepatectomy in rats.

Glycyrrhizin (GL) is a major constituent of licorice root and has been suggested to inhibit the release of high mobility group box-1 (HMGB1), a protein considered representative of damage-associated molecular patterns. We found that GL bound HMGB1 but not RAGE with a moderate equilibrium dissociation constant value based on surface plasmon resonance analysis. This complex formation prevented HMGB1 from binding to RAGE in vitro. The effects of glycyrrhizin on traumatic brain injury (TBI) induced by fluid percussion were examined in rats or mice in the present study. GL was administered intravenously after TBI. Treatment of rats with GL dose-dependently suppressed the increase in BBB permeability and impairment of motor functions, in association with the inhibition of HMGB1 translocation in neurons in injured sites. The beneficial effects of GL on motor and cognitive functions persisted for 7 days after injury. The expression of TNF-α, IL-1β and IL-6 in injured sites was completely inhibited by GL treatment. In RAGE-/- mice, the effects of GL were not observed. These results suggested that GL may be a novel therapeutic agent for TBI through its interference with HMGB1 and RAGE interaction.

When monocytes, macrophages, and vascular endothelial cells are stimulated by RAGE ligands such as HMGB1 and AGEs, NF-κB is activated through activation of MAP kinases, increased ROS production, and activation of small G proteins. phosphorylation of transcription factors is induced. As a result, various inflammation-related factors such as inflammatory cytokines (IL-1, IL-6, TNF-α, etc.), chemokines (MCP-1, etc.), cell adhesion factors (ICAM-1, etc.), matrix metalloproteinases, etc. It has been suggested that this is the molecular basis of various pathogenesis including inflammation, diabetic complications, and tumor growth. In this paper, we discuss various strategies for drug discovery targeting HMGB1 and AGE-RAGE system, and as the first step in developing new molecular-targeted drugs that can suppress the AGEs-RAGE reaction, We describe the construction of an AGEs-RAGE binding assay based on the solid-phase method and the search for drug seeds that exhibit binding blocking activity.

Altered expression of P-glycoprotein (P-gp), a drug efflux transporter expressed by brain capillary endothelial cells (BCECs), may contribute to the development of opioid analgesic tolerance, as demonstrated by cumulative evidence from research. However, the detailed mechanism by which chronic morphine treatment increases P-gp expression remains unexplained. Ezrin/radixin/moesin (ERM) are scaffold proteins that are known to regulate the plasma membrane localization of some drug transporters such as P-gp in peripheral tissues, although a few reports suggest its role in the central nervous system as well. In this study, we investigated the involvement of ERM in the development of morphine analgesic tolerance through altered P-gp expression in BCECs. Repeated treatment with morphine (10 mg/kg/day, s.c. for 5 days) decreased its analgesic effect in the tail-flick test and increased P-gp protein expression in BCECs, as determined by Western blotting. Furthermore, moesin protein expression increased in the same fraction whereas that of ezrin decreased; no change was observed in the radixin expression. Furthermore, immunoprecipitation and immunofluorescence assays revealed interaction between moesin and P-gp molecules, along with co-localization, in BCECs. In conclusion, an increase in moesin expression may contribute to the increased expression of P-gp in BCECs, leading to the development of morphine analgesic tolerance.

Cell-cell interaction through binding of adhesion molecules on monocytes to their ligands on T-cells plays roles in cytokine production and lymphocyte proliferation. High mobility group box 1 (HMGB1), an abundant and conserved nuclear protein, acts in the extracellular environment as a primary pro-inflammatory signal. HMGB1 induces expression of intercellular adhesion molecule (ICAM), B7.1, B7.2 and CD40 on monocytes, resulting in production of interferon (IFN)-γ and tumor necrosis factor (TNF)-α production and lymphocyte proliferation in human peripheral blood mononuclear cells (PBMCs). Histamine inhibits pro-inflammatory cytokine production via histamine H2-receptors; however, it is not known whether histamine inhibits HMGB1 activity. This study was designed to study the inhibitory effect of histamine on HMGB1 activity. We examined the effect of histamine on HMGB1-induced expression of ICAM-1, B7.1, B7.2 and CD40 on monocytes, production of IFN-γ and TNF-α and lymphocyte proliferation in PBMCs. Histamine inhibited HMGB1 activity in a concentration-dependent manner. The effects of histamine were partially ablated by the H2-receptor antagonist, famotidine, and mimicked by the H2/H4-receptor agonists, dimaprit and 4-methylhistamine. Histamine induced cyclic adenosine monophosphate (cAMP) production in the presence and absence of HMGB1. The effects of histamine were reversed by the protein kinase A (PKA) inhibitor, H89, and mimicked by the membrane-permeable cAMP analog, dibutyryl cAMP (dbcAMP), and the adenylate cyclase activator, forskolin. These results together indicated that histamine inhibited HMGB1 activity.

Cell-cell interaction through binding of intercellular adhesion molecule (ICAM), B7.1, B7.2 and CD40 on monocytes to their ligands on T-cells plays a number of roles in cytokine. High mobility group box 1 (HMGB1), an abundant and conserved nuclproduction and lymphocyte proliferationear protein, acts in the extracellular environment as a primary pro-inflammatory signal. The receptor for advanced glycation end products (RAGE), toll-like receptor (TLR)-2 and TLR-4 are receptors for HMGB1. HMGB1 induces pro-inflammatory cytokine production in monocytes and T-cells. This study was designed to study the cellular mechanism of cytokine production. HMGB1 concentration-dependently induced ICAM-1, B7.1, B7.2 and CD40 expression on monocytes, and interferon (IFN)-γ and tumor necrosis factor (TNF)-α production and lymphocyte proliferation in human peripheral blood mononuclear cells (PBMCs). These HMGB1 activities depended on the stimulation of RAGE on monocytes. HMGB1 also up-regulated RAGE, but not TLR-2 or TLR-4, expression on monocytes, which was inhibited by antibodies (Abs) against ICAM-1, B7.1, B7.2 and CD40. These results together indicated that HMGB1 could induce an intimate cellular interplay between monocytes and T-cells in PBMCs through the stimulation and up-regulation of RAGE and other adhesive molecules on monocytes. © 2012 Elsevier B.V. All rights reserved.

We investigated the expression and localization of high-mobility group box chromosomal protein-1 (HMGB-1) in human osteoarthritic (OA) cartilage in relation to the histopathological grade of cartilage destruction, and examined the role of HMGB-1 in the regulation of proinflammatory cytokine expression in chondrocytes. An immunohistochemical study demonstrated that total HMGB-1-positive cell ratios increase as the Osteoarthritis Research Society International (OARSI) histological grade increased. The population of cytoplasmic HMGB-1-positive chondrocytes was especially increased in the deep layers of higher-grade cartilage. The ratios and localization of receptors for advanced glycation end products (RAGE) expression by chondrocytes in Grade 2, 3, and 4 were significantly higher than those in Grade 1. In vitro stimulation with IL-1 beta, but not TNF alpha, significantly upregulated the expression of HMGB-1 mRNA by human OA chondrocytes. Both IL-1 beta and TNFa promoted the translocation of HMGB-1 from nuclei to cytoplasm. IL-1 beta and TNF alpha secretions were stimulated at higher levels of HMGB-1. The results of our study suggest the involvement of HMGB-1 in the pathogenesis of cartilage destruction in OA.

Background and Purpose-High mobility group box-1 (HMGB1) exhibits inflammatory cytokine-like activity in the extracellular space. We previously demonstrated that intravenous injection of anti-HMGB1 monoclonal antibody (mAb) remarkably ameliorated brain infarction induced by middle cerebral artery occlusion in rats. In the present study, we focused on the protective effects of the mAb on the marked translocation of HMGB1 in the brain, the disruption of the blood-brain barrier (BBB), and the resultant brain edema.Methods-Middle cerebral artery occlusion in the rat was used as the ischemia model. Rats were treated with anti-HMGB1 mAb or control IgG intravenously. BBB permeability was measured by MRI. Ultrastructure of the BBB unit was observed by transmission electron microscope. The in vitro BBB system was used to study the direct effects of HMGB1 in BBB components.Results-HMGB1 was time-dependently translocated and released from neurons in the ischemic rat brain. The mAb reduced the edematous area on T2-weighted MRI. Transmission electron microscope observation revealed that the mAb strongly inhibited astrocyte end feet swelling, the end feet detachment from the basement membrane, and the opening of the tight junction between endothelial cells. In the in vitro reconstituted BBB system, recombinant HMGB1 increased the permeability of the BBB with morphological changes in endothelial cells and pericytes, which were inhibited by the mAb. Moreover, the anti-HMGB1 mAb facilitated the clearance of serum HMGB1.Conclusions-These results indicated that the anti-HMGB1 mAb could be an effective therapy for brain ischemia by inhibiting the development of brain edema through the protection of the BBB and the efficient clearance of circulating HMGB1. (Stroke. 2011; 42: 1420-1428.)

Objective-High-mobility group box protein 1 (HMGB1) is a DNA-binding protein and cytokine highly expressed in atherosclerotic lesions, but its pathophysiological role in atherosclerosis is unknown. We investigated its role in the development of atherosclerosis in ApoE-/- mice. Methods and Results-Apolipoprotein E-deficient (ApoE-/-) mice fed a high-fat diet were administered a monoclonal anti-HMGB1 neutralizing antibody, and the effects on lesion size, immune cell accumulation, and proinflammatory mediators were assessed using Oil Red O, immunohistochemistry, and real-time polymerase chain reaction. As with human atherosclerotic lesions, lesions in ApoE-/- mice expressed HMGB1. Treatment with the neutralizing antibody attenuated atherosclerosis by 55%. Macrophage accumulation was reduced by 43%, and vascular cell adhesion molecule-1 and monocyte chemoattractant protein-1 expression was attenuated by 48% and 72%, respectively. CD11c+ dendritic cells were reduced by 65%, and the mature (CD83+) population was reduced by 60%. Treatment also reduced CD4+ cells by nearly 50%. mRNAs in lesions encoding tumor necrosis factor-alpha and interleukin-1 beta tended to be reduced. Mechanistically, HMGB1 stimulated macrophage migration in vitro and in vivo; in vivo, it markedly augmented the accumulation of F4/80+Gr-1(Ly-6C)+ macrophages and also increased F4/80+CD11b+ macrophage numbers. Conclusion-HMGB1 exerts proatherogenic effects augmenting lesion development by stimulating macrophage migration, modulating proinflammatory mediators, and encouraging the accumulation of immune and smooth muscle cells. (Arterioscler Thromb Vasc Biol. 2011;31:313-319.)

Posttransplant diabetes mellitus is a frequent complication among transplant recipients. Ligation of advanced glycation end products (AGEs) with their receptor on monocytes/macrophages plays a role in diabetes complications. The enhancement of adhesion molecule expression on monocytes/macrophages activates T cells, reducing allograft survival. In previous work, we found that toxic AGEs, AGE-2 and AGE-3, induced the expression of intracellular adhesion molecule-1, B7.1, B7.2, and CD40 on monocytes, production of interferon-gamma and tumor necrosis factor alpha, and lymphocyte proliferation during human mixed lymphocyte reaction. AGE-induced up-regulation of adhesion molecule expression was involved in cytokine production and lymphocyte proliferation. Prostaglandin E2 (PGE2) concentration-dependently inhibited the actions of AGE-2 and AGE-3. The effects of PGE2 were mimicked by an EP2 receptor agonist, ONO-AE1-259-01 (11,15-O-dimethyl PGE2), and an EP4 receptor agonist, ONO-AE1-329 [16-(3-methoxymethyl)phenyl-omega-tetranor-3,7dithia PGE1]. An EP2 receptor antagonist, AH6809 (6-isopropoxy-9-oxaxanthene-2-carboxylic acid), and an EP4 receptor antagonist, AH23848 [ (4Z)-7-[ (rel-1S,2S,5R)-5-((1,1'-biphenyl-4-yl)methoxy)-2-(4-morpholinyl)-3-oxocyclopentyl]-4-heptenoic acid], inhibited the actions of PGE2. The stimulation of EP2 and EP4 receptors is reported to increase cAMP levels. The effects of PGE2 were reversed by protein kinase A (PKA) inhibitors and mimicked by dibutyryl cAMP and an adenylate cyclase activator, forskolin. These results as a whole indicate that PGE2 inhibited the actions of AGE-2 and AGE-3 via EP2/EP4 receptors and the cAMP/PKA pathway.

Posttransplant diabetes mellitus (PTDM) is a frequent complication among transplant recipients. Ligation of advanced glycation end products (AGEs) with their receptor (RAGE) on monocytes/macrophages plays roles in the diabetes complications. The enhancement of adhesion molecule expression on monocytes/macrophages activates T-cells, leading to reduced allograft survival. We investigated the effect of four distinct AGE subtypes (AGE-2/AGE-3/AGE-4/AGE-5) on the expressions of intracellular adhesion molecule (ICAM)-1, B7.1, B7.2 and CD40 on monocytes, the production of interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha and the proliferation of T-cells during human mixed lymphocyte reaction (MLR). AGE-2 and AGE-3 selectively induced the adhesion molecule expression, cytokine production and T-cell proliferation. The AGE-induced up-regulation of adhesion molecule expression was involved in the cytokine production and T-cell proliferation. AGE-2 and AGE-3 up-regulated the expression of RAGE on monocytes; therefore, the AGEs may activate monocytes, leading to the up-regulation of adhesion molecule expression, cytokine production and T-cell proliferation.

The up-regulation of adhesion molecule expressions on monocytes enhances cell-to-cell interactions with T cells, leading to cytokine production. Advanced glycation end products (AGEs) are modifications of proteins/lipids that become nonenzymatically glycated after contact with aldose sugars. Among various subtypes of AGEs, glyceraldehyde-derived AGE (AGE-2) and glycolaldehyde-derived AGE (AGE-3) induce the expressions of intercellular adhesion molecule-1, B7.1, B7.2, and CD40 on monocytes, the production of interferon-gamma and tumor necrosis factor-alpha, and the lymphocyte proliferation in human peripheral blood mononuclear cells. Nicotine is reported to inhibit the activation of monocytes via nicotinic acetylcholine receptor alpha7 subunit (alpha7-nAChR). In the present study, we found that nicotine inhibited the actions of AGE-2 and AGE-3. A nonselective and selective alpha7-nAChR antagonist, mecamylamine and alpha-bungarotoxin, reversed the inhibitory effects of nicotine, suggesting the involvement of alpha7-nAChR stimulation. Nicotine induced the expression of cyclooxygenase-2, prostaglandin E(2) (PGE(2)), and cAMP in the presence and absence of AGE-2 and AGE-3. PGE(2) is known to activate the EP(2)/EP(4) receptor, increasing the cAMP level and protein kinase A (PKA) activity. The actions of nicotine were reversed in part by an EP(2)-receptor antagonist, AH6809, an EP(4)-receptor antagonist, AH23848, and a PKA inhibitor, N-[2-(p-bromocinnamyl-amino)ethyl]-5-isoquinolinesulfonamide dihydrochloride (H89). These results indicate that the mechanism of action of nicotine may be partially via endogenous PGE(2) production.

Cell-to-cell interaction through binding of intercellular adhesion molecule-1 (ICAM-1) and CD40 on monocytes to their ligands on T-cells plays crucial roles in cytokine production. Advanced glycation end products (AGEs) subtypes induce complications in diabetes. In a previous study, we found that glyceraldehyde-derived AGE (AGE-2) and glycolaldehyde-derived AGE (AGE-3) at 100 microg/ml induced the expressions of ICAM-1 and CD40 on monocytes and the production of interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha in human peripheral blood mononuclear cells. beta(2)-adrenoceptor stimulation has been demonstrated to modulate the production of inflammatory mediators. In the present study, we found that norepinephrine, epinephrine and isoproterenol inhibited AGE-2- and AGE-3-induced adhesion expression and cytokine production in a concentration-dependent manner. The action of these catecholamines was antagonized by beta(2)-adrenoceptor antagonist, but not by alpha(1)-, alpha(2)- and beta(1)-adrenoceptor antagonist. beta(2)-adrenoceptor agonists, salbutanol and terbutaline inhibited AGE-2- and AGE-3-induced adhesion expression and cytokine production, but alpha(1)-, alpha(2)- and beta(1)-adrenoceptor agonist had no effect, indicating that the stimulation of beta(2)-adrenoceptor might improve AGEs-initiated complications in diabetes.

Advanced glycation end product (AGE) subtypes, proteins or lipids that become glycated after exposure to sugars, induce complications in diabetes. Among the various AGE subtypes, glyceraldehyde-derived AGE (AGE-2) and glycolaldehyde-derived AGE (AGE-3) have been indicated to play roles in inflammation in diabetic patients. The engagement of AGEs and receptor for AGEs activates monocytes. Because the engagement of intercellular adhesion molecule-1 (ICAM-1), B7.1, B7.2, and CD40 on monocytes with their ligands on T cells plays roles in cytokine production, we investigated the effects of AGE-2 and AGE-3 on the expressions of ICAM-1, B7.1, B7.2, and CD40 on monocytes, the production of interferon gamma and tumor necrosis factor alpha, and the lymphocyte proliferation in human peripheral blood mononuclear cells and their modulation by prostaglandin E(2) (PGE(2)). AGE-2 and AGE-3 induced the expressions of adhesion molecule, the cytokine production, and the lymphocyte proliferation. PGE(2) concentration-dependently inhibited the actions of AGE-2 and AGE-3. The effects of PGE(2) were mimicked by an E-prostanoid (EP)(2)-receptor agonist, 11,15-O-dimethyl prostaglandin E(2) (ONO-AE1-259-01), and an EP(4) receptor agonist, 16-(3-methoxymethyl)phenyl-omega-tetranor-3,7-dithia prostaglandin E(1) (ONO-AE1-329). An EP(2)-receptor antagonist, 6-isopropoxy-9-oxaxanthene-2-carboxylic acid (AH6809), and an EP(4)-receptor antagonist, (4Z)-7-[ (rel-1S,2S,5R)-5-(1,1'-biphenyl-4-yl)methoxy)-2-(4-morpholinyl)-3-oxocyclopentyl]-4-heptenoic acid (AH23848), inhibited the actions of PGE(2). The stimulation of EP(2) and EP(4) receptors is reported to increase cAMP levels. The effects of PGE(2) were reversed by a protein kinase A (PKA) inhibitor, H89, and mimicked by a dibutyryl cAMP and an adenylate cyclase activator, forskolin. These results as a whole indicated that PGE(2) inhibited the actions of AGE-2 and AGE-3 via EP(2)/EP(4) receptors and the cAMP/PKA pathway.

Histidine-rich glycoprotein (HRG) is a heparin-binding glycoprotein present in plasma at 100 mu g/ml. A recent Study revealed that HRG Suppressed heparin-dependent basic fibroblast growth factor (bFGF)-induced angiogenesis. Additionally, we reported that hi.-h mobility group box 1 (HMGB1) in complex with heparin induces angiogenesis; therefore, we examined the effect of HRG oil heparin-dependent HMGB1-induced angiogenesis in the present study. HRG completely inhibited angiogenesis induced by HMGB1 in complex with heparin. HRG inhibited the diffusion of a complex of HMGB1 with heparin front matrigel into surrounding tissue. HRG also competed with HMGB1 for heparin binding in vitro. Moreover, HRG inhibited heparin-dependent vascular endothelial growth factor-A(165) (VEGF-A(165))-induced angiogenesis. These results Strongly suggested that HRG might be an inhibitor of angiogenesis induced by growth factors with heparin binding activity and that HRG may be a potential drug for angiogenic diseases, including tumor growth. (C) 2009 Elsevier B.V. All rights reserved.

High Mobility Group Box-1 (HMGB1) has been identified as a chromatin-binding non-histone protein localized in the cell nucleus, and is thought to play an important role in maintaining chromatin structure, regulating transcriptional activity, and DNA repair. However, in 1999, a research group led by Kevin Tracey et al. rediscovered it as a delayed mediator of septic shock. Blood-brain barrier breakdown in the acute phase of ischemic stroke is thought to be brought about by activation of vascular endothelial cells, microglia, astroglia, and circulating leukocytes, and their interactions, resulting in intracerebral inflammatory reactions. The release of HMGB1 from necrotic cells during such processes may play an important role in brain inflammation. The dynamics of HMGB1 in the brain during the acute phase of cerebral ischemia, which have recently been reported one after another, and treatment using shRNAs targeting HMGB1 and anti-HMGB1 antibodies will be reviewed, focusing on the findings of the authors.

Angiogenesis involves complex processes mediated by several factors and is associated with inflammation and wound healing. High mobility group box 1 (HMGB1) is released from necrotic cells as wen as macrophages and plays proinflammatory roles. In the present study, we examined whether HMGB1 would exhibit angiogenic activity in a matrigel plug assay in mice. HMGB1 in combination with heparin strongly induced angiogenesis, whereas neither HMGB1 nor heparin alone showed such angiogenic activity. The heparin-dependent induction of angiogenesis by HMGB1 was accompanied by increases in the expression of tumor necrosis factor-alpha (TNF-alpha) and vascular endothelial growth factor-A(120) (VEGF-A(120)). It is likely that the dependence of the angiogenic activity of HMGB1 on heparin was due to the efficiency of the diffusion of the HMGB1-heparin complex from matrigel to the surrounding areas. VEGF-A(165) possessing a heparin-binding domain showed a pattern of heparin-dependent angiogenic activity similar to that of HMGB1. The presence of heparin also inhibited the degradation of HMGB1 by plasmin in vitro. Taken together, these results suggested that HMGB1 in complex with heparin possesses remarkable angiogenic activity, probably through the induction of TNF-alpha and VEGF-A(120).

Advanced glycation end products (AGEs) are modifications of proteins/lipids that become nonenzymatically glycated after contact with aldose sugars. Among various subtypes of AGEs, glyceraldehyde-derived AGE (AGE-2) and glycolaldehyde-derived AGE (AGE-3) are suggested to play roles in inflammation in diabetic patients. Because the engagement of intercellular adhesion molecule (ICAM)-1, B7.1, B7.2, and CD40 on monocytes with their ligands on T cells plays roles in cytokine production, we examined the effects of AGE-2 and AGE-3 on the expression of adhesion molecules and cytokine production in human peripheral blood mononuclear cells (PBMC) and their modulation by histamine in the present study. AGE-2 and AGE-3 induced the expressions of ICAM-1, B7.1, B7.2, and CD40 on monocytes and the production of interferon-gamma in PBMC. Histamine concentration-dependently inhibited the action of AGE-2 and AGE-3. The effects of histamine were antagonized by an H2 receptor antagonist, famotidine, and mimicked by H2/H4 receptor agonists dimaprit and 4-methylhistamine. Histamine induced cAMP production in the presence and absence of AGE-2 and AGE-3. The effects of histamine were reversed by a protein kinase A (PKA) inhibitor, N-[2-(4-bromo-cinnamylamino)ethyl]-5-isoquinoline (H89), and mimicked by a dibutyryl cAMP and an adenylate cyclase activator, forskolin. These results as a whole indicated that histamine inhibited the AGE-2- and AGE-3-induced adhesion molecule expression and cytokine production via H2 receptors and the cAMP/PKA pathway.

Interaction between the receptor for advanced glycation end products (RAGE) and its ligands has been implicated in the pathogenesis of various inflammatory disorders. In this study, we establish an in vitro binding assay in which recombinant human high-mobility group box 1 (rhHMGB1) or recombinant human S100A12 (rhS100A12) immobilized on the microplate binds to recombinant soluble RAGE (rsRAGE). The rsRAGE binding to both rhHMGB1 and rhS100A12 was saturable and dependent on the immobilized ligands. The binding of rsRAGE to rhS100A12 depended on Ca2+ and Zn2+, whereas that to rhHMGB1 was not. Scatchard plot analysis showed that rsRAGE had higher affinity for rhHMGB1 than for rhS100A12. rsRAGE was demonstrated to bind to heparin, and rhS100A12, in the presence of Ca2+, was also found to bind to heparin. We examined the effects of heparin preparations with different molecular sizes - unfractionated native heparin (UFH), low molecular weight heparin (LMWH) 5000Da, and LMWH 3000Da - on the binding of rsRAGE to rhHMGB1 and rhS100A12. All 3 preparations concentration-dependently inhibited the binding of rsRAGE to rhHMGB1 to a greater extent than did rhS100A12. These results suggested that heparin's anti-inflammatory effects can be partly explained by its blocking of the interaction between HMGB1 or S100A12 and RAGE. On the other hand, heparin would be a promising effective remedy against RAGE-related inflammatory disorders.

Advanced glycation end products (AGEs) are proteins or lipids that become glycated after exposure to diverse reducing sugars. Accumulation of AGEs induces diabetes complications. Microinflammation is a common major mechanism in the pathogenesis of diabetic vascular complications. Activation of monocytes/macrophages and T cells plays roles in the pathogenesis of atherosclerosis. The activation of T cells requires the enhanced expression of adhesion molecules on monocytes. AGEs activate monocytes by engaging the receptor for AGE (RAGE); however, little is known about the profile of agonist activity of diverse AGE moieties on monocytes. We investigated the effect of four distinct AGE subtypes (AGE-modified bovine serum albumin; AGE-2, AGE-3, AGE-4, and AGE-5) at concentrations ranging from 0.1 to 100 microg/ml on the expression of intercellular adhesion molecule-1, B7.1, B7.2, and CD40 on monocytes and its impact on the production of interferon-gamma and tumor necrosis factor-alpha in human peripheral blood mononuclear cells. Among the AGEs examined, AGE-2 and AGE-3 selectively induced adhesion molecule expression and cytokine production. Antagonism experiments using antibodies against adhesion molecules demonstrated that cell-to-cell interaction between monocytes and T/natural killer cells was involved in AGE-2- and AGE-3-induced cytokine production. AGE-2 and AGE-3 up-regulated the expression of RAGE on monocytes. The effects of AGE-2 and AGE-3 were inhibited by nuclear factor-kappaB and p38 mitogen-activated protein kinase inhibitors. These results indicated that AGE-2 and AGE-3 activated monocytes via RAGE, leading to the up-regulation of adhesion molecule expression and cytokine production.

Lipopolysaccharide (LPS) is one of the major causes of septic shock. The polymyxin B-immobilized filter column (PMX) was developed for the adsorption of endotoxin by direct hemoperfusion and has been used for the treatment of LPS-induced septic shock. In this study, we demonstrated that PMX also specifically bound monocytes from the peripheral blood leukocytes of septic patients by mean of an analysis of bound cells using immunocytochemical and electron microscopic techniques. The specific removal of monocytes from septic patients may produce beneficial effects by reducing the interaction between monocytes and functionally associated cells including vascular endothelial cells.

Ischemic brain infarction is high among th causes of death in Japan, and the medical and social burden by severe sequela is also extremely serious. In this symposium, we show that treatment with anti-high mobility group box 1 (HMGB1) monoclonal antibody (mAb) remarkably ameliorated brain infarction induced by 2-hour occlusion of the middle cerebral artery in rats, even when the mAb was administered after the start of reperfusion. Whereas HMGB1 is usually localized in nucleus, after stimulation it is secreted into extracellular space by an unknown non-classical pathway, and exhibits an inflammatory cytokine-like activity. Treatment with mAb reduced infarct size, and the accompanying neurological deficits in locomotor function were significantly improved. In addition, some biochemical markers such as permeability of the blood-brain barrier, the expression of tumor necrosis factor-alfa, inducible nitric oxide synthase and matrix metalloproteinase-9 were altered by mAb injection. These findings indicate the usefulness of HMGB1 as a novel therapeutic to target ischemic stroke.

BACKGROUND: Coronary ischemia-reperfusion (I/R) injury causes cardiomyocyte necrosis in a multi-step process that includes an inflammatory reaction. A recent study has suggested that high-mobility group box 1 (HMGB1) is a late mediator of lethal sepsis and an early mediator of inflammation and necrosis following I/R injury. In the present study a neutralizing monoclonal antibody (mAb) for HMGB1 was used to clarify the role of HMGB1 in cardiac I/R injury. METHODS AND RESULTS: Rats underwent 30 min of left coronary artery occlusion followed by 60 min reperfusion. An intravenous injection of anti-HMGB1 mAb or control IgG was administered just before reperfusion. The infarct size was enlarged in the anti-HMGB1 mAb group in comparison with the control group (p<0.05). The treatment of anti-HMGB1 mAb significantly increased the plasma troponin-T and norepinephrine (NE) content in the heart in comparison with the control (p<0.05). Moreover, the production of dihydroxyphenylglycol was reduced in the anti-HMGB1-treated group (p<0.05). CONCLUSION: This study shows for the first time the effects of treatment with neutralizing anti-HMGB1 mAb on I/R injury in the rat heart. The findings support the novel view that I/R-induced HMGB1 may be an important factor in the modulation of interstitial NE.

Inflammatory reactions play an important role in ischaemia/reperfusion injury in various organs. Since histamine H(4) action has been shown to prevent the development of ischaemia/reperfusion liver injury, we examined the effects of dimaprit, a histamine H(2)/H(4) receptor agonist, on ischaemia-induced cytokine release and liver damage. Male Wistar rats (300 g) were subjected to warm ischaemia for 30 min. by occlusion of the left portal vein and hepatic artery under halothane anaesthesia. Saline or dimaprit (20 mg/kg, subcutaneously) was injected immediately after reperfusion of blood flow. Transient ischaemia provoked severe liver damage 24 hr after reperfusion, and the plasma concentrations of alanine transaminase and aspartate transaminase were 4600 IU/l and 13,200 IU/l, respectively. The values in the dimaprit group were 55% and 46% of those in control animals, respectively. Dimaprit also reduced the infarct size to 50%. Liver ischaemia markedly increased interleukin-12 levels 2-24 hr after reperfusion. The dimaprit treatment depressed the values to 40-64% of those in the corresponding control group 4-24 hr after reperfusion. Since interleukin-12 facilitates cell-mediated cytotoxicity, the protective effect of dimaprit may be attributed to regulation of cytokine release during reperfusion.

LPS stimulates CD14/Toll-like receptor (TLR) 4, leading to induce TNF-alpha production. Cell-to-cell interaction through the engagement between intercellular adhesion molecule (ICAM) 1 on monocytes and its ligand on T cells has been suggested to play a role in the TNF-alpha production by LPS-treated human peripheral blood mononuclear cells (PBMCs). Adenosine is reported to inhibit LPS-induced TNF-alpha production. However, little is known about the mechanism of the inhibitory effects induced by adenosine on the LPS-induced immune responses. We found that adenosine inhibited the expression of ICAM-1 and the production of TNF-alpha by human PBMC via adenosine A2A receptor in the presence of LPS. However, the stimulation of A1R or A3R enhanced the actions of adenosine. Adenosine had no effect on the expression of CD14 and TLR-4, suggesting that the inhibitory effects of adenosine on the LPS actions might be independent of the expression of CD14 and TLR-4. Thus, adenosine differentially regulates the expression of ICAM-1 and the production of TNF-alpha through plural subtypes of receptors.

The high mobility group box-1 (HMGB1), originally identified as an architectural nuclear protein, exhibits an inflammatory cytokine-like activity in the extracellular space. Here we show that treatment with neutralizing anti-HMGB1 monoclonal antibody (mAb; 200 microg, twice) remarkably ameliorated brain infarction induced by 2-h occlusion of the middle cerebral artery in rats, even when the mAb was administered after the start of reperfusion. Consistent with the 90% reduction in infarct size, the accompanying neurological deficits in locomotor function were significantly improved. Anti-HMGB1 mAb inhibited the increased permeability of the blood-brain barrier, the activation of microglia, the expression of TNF-alpha and iNOS, and suppressed the activity of MMP-9, whereas it had little effect on blood flow. Intracerebroventricular injection of HMGB1 increased the severity of infarction. Immunohistochemical study revealed that HMGB1 immunoreactivity in the cell nuclei decreased or disappeared in the affected areas, suggesting the release of HMGB1 into the extracellular space. These results indicate that HMGB1 plays a critical role in the development of brain infarction through the amplification of plural inflammatory responses in the ischemic region and could be an outstandingly suitable target for the treatment. Intravenous injection of neutralizing anti-HMGB1 mAb provides a novel therapeutic strategy for ischemic stroke.

The cell-to-cell interaction through binding of intercellular adhesion molecule (ICAM)-1 on monocytes to their ligands lymphocyte function-associated antigen (LFA)-1 on T-cells plays important roles in cytokine production and T-cell proliferation. Interleukin (IL)-18, which plasma levels are elevated in patients during acute rejection following organ transplantation, induces the expression of ICAM-1 on monocytes, production of interferon (IFN)-gamma and IL-12 and lymphocyte proliferation during human mixed lymphocyte reaction. Activation of the adenosine A(2A) receptor on during reperfusion of various tissues has been found to markedly reduce ischemia-reperfusion injury. In the present study, we examined the effect of adenosine at increasing concentrations ranging from 0.1 to 100 microM on the IL-18-enhanced expression of ICAM-1, production of IFN-gamma and IL-12 and lymphocyte proliferation during human mixed lymphocyte reaction. Adenosine inhibited the IL-18-initiated immune responses. The IC(50) values of adenosine for inhibition of the IL-18-enhanced ICAM-1 expression, IFN-gamma production and lymphocyte proliferation were 20 microM, respectively. The actions of adenosine depended on the stimulation of adenosine A(2A) receptor. An inhibitor of protein kinase A (PKA) at 100 microM inhibited the actions of adenosine, suggesting that PKA might be involved in the actions of adenosine. On the other hand, the stimulation of adenosine A(1) and A(3) receptor blocked the actions of adenosine A(2A) receptor stimulation. These results suggest that adenosine inhibits the immune responses during mixed lymphocyte reaction via adenosine A(2A) receptor.

The cell-to-cell interaction through binding intercellular adhesion molecule (ICAM)-1 and CD40 on monocytes and their ligands such as lymphocyte function-associated antigen (LFA)-1 and CD40 ligand (CD40L) on T-cells plays roles in cytokine production and T-cell proliferation. Interleukin (IL)-18, which is elevated in the plasma during acute rejection after organ transplantation, induces the expression of ICAM-1 and CD40 on monocytes, the production of interferon (IFN)-gamma and IL-12 and the proliferation of T-cells during the human mixed lymphocyte reaction (MLR). In addition to the cholesterol lowering effect, statins improve patient survival and decrease rejection episodes in transplant recipients. In the present study, we investigated the difference of effect of statins and calcineurin inhibitors during MLR. 3-Hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductase inhibitors, fluvastatin and pravastatin and statin-derived LFA-1 inhibitors, LFA703 and LFA878, which did not inhibit HMG-CoA reductase, suppressed the production of IFN-gamma and IL-12 and the lymphocyte proliferation as well as the expression of ICAM-1 and CD40 on monocytes regardless of the presence of IL-18. However, the calcineurin inhibitors, tacrolimus and cyclosporine A (CsA), inhibited the IL-18-enhanced cytokine production and lymphocyte proliferation without any effect on the adhesion molecule expression. Thus, the action mechanism of stain is different from that of calcineurin inhibitors.

Adenosine inhibited interleukin (IL)-18 production in lipopolysaccharide (LPS)-stimulated monocytes. The action of adenosine was antagonized by an adenosine A2A-receptor (A2AR) antagonist and was mimicked by an A2AR agonist, suggesting that the stimulation of A2AR may be involved in the actions of adenosine. On the other hand, the stimulation of A1R and A3R inhibited the actions of A2AR stimulation, whereas the stimulation of A2BR had no effect on them. Activation of A2AR is known to increase cyclic adenosine monophosphate (cAMP) levels and to activate protein kinase A (PKA). A PKA inhibitor prevented the actions of A2AR stimulation, indicating that the action mechanism of A2AR stimulation may be via the activation of the cAMP/PKA pathway.

Cell-to-cell interaction through binding intercellular adhesion molecule (ICAM)-1, B7.1, B7.2 and CD40 on monocytes and their ligands on T-cells plays roles in cytokine production and T-cell proliferation. Interleukin (IL)-18, which is elevated in the plasma during acute rejection after organ transplantation, induces the expression of ICAM-1, B7.1, B7.2 and CD40, production of interferon (IFN)-gamma and IL-12 and proliferation of lymphocytes during human mixed lymphocyte reaction. Nicotine is known to inhibit the production of pro-inflammatory cytokines from macrophages through the stimulation of nicotinic acetylcholine receptor alpha7 subunit. In the present study, we examined the effect of increasing concentrations ranging from 0.1 to 100 microM of nicotine on the expression of ICAM-1, B7.1, B7.2 and CD40, production of IFN-gamma and IL-12 and proliferation of lymphocytes during mixed lymphocyte reaction treated with IL-18 at 100 ng/ml for 48 h. Nicotine inhibited the expression of adhesion molecules, cytokine production and lymphocyte proliferation. The IC50 values of nicotine for inhibition of the IL-18-enhanced ICAM-1 expression, IFN-gamma production and proliferation were 1, 1 and 2 microM, respectively. A non-selective and a selective antagonist for nicotinic acetylcholine receptor alpha7 subunit, mecamylamine and alpha-bungarotoxin abolished the effects of nicotine. The actions of nicotine might depend on stimulation of nicotinic acetylcholine receptor alpha7 subunit. Nicotine induced prostaglandin E(2) production during mixed lymphocyte reaction. The inhibitors of cyclooxygenase (COX)-2 and protein kinase A (PKA) at 100 microM inhibited the actions of nicotine, suggesting that the endogenous prostaglandin E(2) might be, at least, partially involved the actions of nicotine.

We examined whether treatment with amodiaquine, a potent inhibitor of histamine N-methyltransferase protects mice from Propionibacterium acnes (P. acnes)-primed and lipopolysaccharide (LPS)-induced hepatitis. The subcutaneous injection of amodiaquine (2 and 5 mg/kg) significantly increased the histamine levels in the liver in comparison to saline treated mice. Pretreatment with amodiaquine also improved the survival rate of the hepatitis mice, and this improvement was partially associated with the decrease in serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Amodiaquine partially suppressed increases of tumor necrosis factor (TNF)-alpha in the serum and TNF-alpha mRNA expression in the liver, whereas the expression of interleukin (IL)-18, interferon (IFN)-gamma and IL-12 in the liver was not changed by amodiaquine treatment. In conclusion, the present findings suggested that the elevation of endogenous histamine by amodiaquine may thus play a protective role through the regulation of TNF-alpha production in endotoxin-induced hepatic injury mice. (c) 2006 Elsevier B.V. All rights reserved.

Nicotine is thought to inhibit the production of proinflammatory cytokines from macrophages through an anti-inflammatory pathway that is dependent on nicotinic acetylcholine receptor alpha7 subunit (alpha7-nAChR). IL-18, an important proinflammatory cytokine, is reported to induce the expression of adhesion molecules on monocytes, thus enhancing cell-to-cell interactions with T-cells and contributing to IL-18-initiated cytokine production. Accordingly, inhibition of IL-18 suppresses systemic inflammatory responses. In the present study, we found that nicotine inhibited the IL-18-enhanced expression of ICAM-1, B7.2, and CD40 on monocytes, and the production of IL-12, IFN-gamma, and TNF-alpha by PBMC. A nonselective and a selective alpha7-nAChR antagonist, mecamylamine, and alpha-bungarotoxin abolished the effects of nicotine, suggesting that this depends on alpha7-nAChR stimulation. It is reported that nicotine induces prostaglandinE2 (PGE(2)) production in PBMC through the up-regulation of cyclooxygenase (COX)-2 expression. PGE(2) is known to activate the EP2/EP4-receptor, leading to an increase in cyclic adenosine monophosphate (cAMP) levels and protein kinase A (PKA) activity. Consistent with this, we found that COX-2 and PKA inhibitors prevented the effects of nicotine on adhesion molecule expression and cytokine production, indicating that the mechanism of action of nicotine may be via endogenous PGE(2) production.

Nafamostat mesilate (NM) is a synthetic protease inhibitor with various biological effects. To determine its effect on liver injury related to sepsis, we investigated the effects of NM on lipopolysaccharide (LPS)-induced liver injury. Wistar rats were allocated into two groups; the NM group underwent intraperitoneal NM administration 30 min before LPS administration, and the control group underwent PBS administration. Serum AST and ALT levels were significantly decreased in NM-treated rats. Reduced levels of TNF-alpha, IL-1beta, and IFN-gamma were observed after LPS administration in NM-treated rats. No significant differences were observed in IL-6 levels between the NM and the control group. In contrast, HGF levels were significantly increased only in control rats. NM treatment decreased protein and mRNA levels of TLR-4 and CD14. Our data suggest that NM treatment has protective effects against LPS-induced hepatotoxicity through downregulation of TLR4 and CD14 in liver, which decreased TNF-alpha, IL-1beta, and IFN-gammaproduction in liver.

The lipopolysaccharide (LPS)-receptor complex, CD14/toll-like receptor 4, is known to play a role in the immune responses during sepsis. Excessive inflammation and tumor necrosis factor (TNF)-alpha synthesis have been reported to cause morbidity and mortality in endotoxemia and sepsis. Cell-to-cell interaction through the engagement between intercellular adhesion molecule 1, B7.1, and CD40 on monocytes and their ligands on T cells has been suggested to play a role in the inflammatory response such as TNF-alpha and interleukin 10 production. Nicotine, with the stimulation of the nicotinic acetylcholine receptor alpha7 subunit (alpha7-nAChR), has now become the focus of attention because of its anti-inflammatory effects. However, little is known about the mechanism of the inhibitory effects induced by nicotine on the LPS-induced immune responses. In the present study, we found that nicotine suppressed the expression of CD14, toll-like receptor 4, intercellular adhesion molecule 1, B7.1, and CD40 on monocytes and the production of TNF-alpha, but not interleukin 10, in human peripheral blood mononuclear cells in the presence of LPS. The actions of nicotine were reversed by a nonselective and a selective alpha7-nAChR antagonist, mecamylamine and alpha-bungarotoxin, respectively. Therefore, nicotine might inhibit the LPS receptor complex expression via alpha7-nAChR, thus leading to a decrease in the adhesion molecule expression and TNF-alpha production. Moreover, we demonstrated that a nuclear factor-kappaB and a p38 mitogen-activated protein kinase inhibitor mimicked the actions of nicotine in the presence of LPS. These results suggested that the nuclear factor-kappaB and p38 mitogen-activated protein kinase might be involved in the actions of nicotine.

Nicotine inhibited interleukin (IL)-18 and -12 production in lipopolysaccharide (LPS)-stimulated monocytes, and the action of nicotine was antagonized by a non-selective and a selective alpha7 nicotinic acetylcholine receptor (alpha7-nAChR) antagonist, suggesting that the stimulation of alpha7-nAChR may be involved in the action of nicotine. Nicotine is reported to induce prostaglandin E(2) (PGE(2)) production in monocytes through the up-regulation of cyclooxygenase (COX)-2 expression. PGE(2) is known to increase cAMP levels and to activate protein kinase A (PKA). COX-2 and PKA inhibitors prevented the action of nicotine, indicating that the mechanism of action of nicotine may be via endogenous PGE(2) production.

The present study demonstrates a possible mechanism for the improvement of gastrointestinal cancer patients' prognosis by the histamine receptor type 2 (H2R) antagonist cimetidine. This agent, but not the H2R antagonists ranitidine and famotidine, induced the production of an antitumor cytokine, interleukin (IL)-18, by human monocytes and dendritic cells (DC). In fact, ranitidine and famotidine antagonized cimetidine-induced IL-18 production. Cimetidine induced the activation of caspase-1, which is reported to modify immature IL-18 to mature/active IL-18, and the elevation of intracellular cAMP, leading to the activation of protein kinase A (PKA). The PKA inhibitor H89 abolished the IL-18 production induced by cimetidine. Moreover, the effects of cimetidine on IL-18 production were reproduced in peripheral blood mononuclear cells from wild-type mice, but not in those from H2R knockout mice. In conclusion, cimetidine, a partial agonist for H2R, has a pharmacological profile different from ranitidine and famotidine, possibly contributing to its antitumor activity on gastrointestinal cancers.

Statins, which inhibit 3-hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductase, are thought to reduce the risk of cancer through the inhibition of Ras farnesylation and serum lipid level. A pleiotropic proinflammatory cytokine, interleukin-18 (IL-18), is reported to exhibit significant antitumor activities through the activation of cytotoxic T lymphocytes and natural killer cells and the inhibition of angiogenesis. Previously, we found that pravastatin, fluvastatin, and simvastatin induced the production of IL-18 in human monocytes. The addition of mevalonate abolished the IL-18 production induced by pravastatin, fluvastatin, and simvastatin, indicating that the IL-18 production might be a result of the inhibition of HMG-CoA reductase. We present a new hypothesis that the production of IL-18 might play roles in the action of statins on cancer.

Interleukin (IL)-18, which is elevated in the plasma during acute rejection after organ transplantation, is known to induce the expression of intercellular adhesion molecule (ICAM)-1, B7.1, B7.2, CD40 and CD40 ligand (CD40L) on monocytes, the production of interferon (IFN)-gamma and IL-12 and the proliferation of lymphocytes during the human mixed lymphocyte reaction (MLR). Ciprofloxacin (CIP), which is useful for the clinical treatment of infections due to its antibacterial properties after transplantation, was shown to suppress the IFN-gamma and IL-12 production, the lymphocyte proliferation and the ICAM-1, B7.1, B7.2 and CD40 expression on monocytes during MLR in the presence of IL-18. CIP also induced the production of prostaglandin (PG) E2. In order to determine whether the effects of CIP on the expression of the activation markers were due to CIP-dependent production of PGE2, we examined the effect of cyclooxygenase (COX)-2 and protein kinase A (PKA) inhibitors on the actions of CIP. Thereby, the inhibitors were found to abolish the actions of CIP. These results therefore suggest that CIP might exert its immune modulatory effects via the production of PGE2.

CD14/toll-like receptor (TLR)-4 complex on monocytes/macrophages can bind lipopolysaccharide (LPS) and transduce the signals intracellularly. An antibacterial drug, ciprofloxacin (CIP), has been reported to modulate the inflammatory and immune responses. In the present study, we examined the effects of CIP on the LPS-induced activation of monocytes isolated from human peripheral blood mononuclear cells (PBMC). CIP suppressed the expression of CD14, TLR-4, intercellular adhesion molecule (ICAM)-1, B7.1, B7.2, and CD40 and the production of tumor necrosis factor (TNF)-alpha induced by LPS in monocytes. CIP induced the production of prostaglandin (PG)E2 and increased intracellular cyclic adenosine monophosphate (cAMP) levels. Cyclooxygenase (COX)-2 inhibitors, NS398 and indomethacin, reversed the effects of CIP on TNF-alpha production and reduced the levels of different surface antigens, whereas a protein kinase A (PKA) inhibitor, H89, did not. Therefore, CIP might regulate the TNF-alpha production induced by LPS by inhibiting the expression of LPS receptor complex, which seems to be mediated by COX-2 but not the cAMP/PKA pathway.

We examined the effects of beta2-adrenergic receptor (beta2-AR) agonists on monocyte-derived cytokines, interleukin (IL)-18 and IL-12 production in lipopolysaccharide (LPS)-stimulated monocytes derived from human peripheral blood mononuclear cells (PBMCs), as in vitro model of sepsis. The study found that beta2-AR agonists inhibited IL-18 and IL-12 production in monocytes, and that AR agonist activity was antagonized by the selective beta2-AR antagonist, butoxamine. The selective beta2-AR agonists salbutamol and terbutaline induced a similar inhibitory pattern of IL-18 and IL-12 production. IL-12 production induced by LPS was inhibited by anti-IL-18 Ab, but IL-18 production by LPS was not inhibited by anti-IL-12 Ab, showing that LPS induced IL-18 production without IL-12 production. Therefore, the stimulation of beta2-AR might be beneficial in the treatment of sepsis through inhibiting LPS-elicited IL-18.

The effects of statins on immune response depend on the inhibition of 3-hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductase and leukocyte function-associated antigen (LFA)-1, which is a ligand of intercellular adhesion molecule (ICAM)-1. Simvastatin, an HMG-CoA reductase inhibitor with mild inhibition of LFA-1, induced the production of interleukin (IL)-18, tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma in human peripheral blood mononuclear cells (PBMC). The IL-18 production is located upstream of the cytokine cascade activated by simvastatin. Moreover, simvastatin concentration-dependently inhibited the expression of ICAM-1 and induced the expression of CD40 on monocytes. In the presence of IL-18, simvastatin suppressed the expression of ICAM-1 and CD40 as well as the production of IL-12, TNF-alpha and IFN-gamma in PBMC, contributing to the anti-inflammatory effect of simvastatin. The effects of simvastatin were abolished by the addition of the product of the HMG-CoA reductase, mevalonate, indicating the involvement of HMG-CoA reductase in the action of simvastatin.

Ciprofloxacin, a fluorinated 4-quinolone, is useful for the clinical treatment of infections due to its antibacterial properties and also modulates the immune response of monocytes isolated from human peripheral blood mononuclear cells. In the present study, we found that ciprofloxacin induced the production of prostaglandin E(2) in monocytes in a concentration-dependent manner regardless of the presence of interleukin-18 by enhancing the expression of cyclooxygenase-2 protein and that this in turn led to the elevation of intercellular cyclic AMP in monocytes via the stimulation of prostaglandin receptors. The prostaglandin E(2) and cyclic AMP production increased by ciprofloxacin was inhibited by indomethacin, a nonselective cyclooxygenase-2 inhibitor, and NS398, a selective cyclooxygenase-2 inhibitor. In addition, ciprofloxacin suppressed the interleukin-18-induced production of tumor necrosis factor alpha, gamma interferon, and interleukin-12 in peripheral blood mononuclear cells by inhibiting the expression of intercellular adhesion molecule 1, B7.1, B7.2, and CD40 on monocytes, and this effect could be reversed by the addition of indomethacin or NS398. These results indicate that ciprofloxacin exerts immunomodulatory activity via the production of prostaglandin E(2) and imply therapeutic potential of ciprofloxacin for the treatment of systemic inflammatory responses initiated by interleukin-18.

Little has been reported on the drugs inducing production of monocyte-derived cytokines like interleukin (IL)-18 and IL-12. We found that nafamostat mesilate elicits IL-12, IL-18, tumor necrosis factor-alpha and interferon-gamma production, and the expression of intercellular adhesion molecules-1, B7.1, B7.2, CD40, and CD40 ligand in human peripheral blood mononuclear cells. The cytokine production and adhesion molecule expression were abolished by anti-IL-12 and IL-18 antibodies. Therefore, IL-18 and IL-12 may play roles in the significant and immediate effects of nafamostat mesilate.

We found that striptease-positive mast cells were abundant in the invasive front of human colon adenocarcinoma by examining 30 cases. Because tryptase has been suggested to be the agonist proteinase for protease-activated receptor-2 (PAR-2), we investigated the effects of stimulation of PAR-2 by tryptase on the cell signaling and proliferation of DLD-1, a human colon carcinoma cell line. PAR-2 stimulation by tryptase induced the increase in [Ca(2+)](i), which was desensitized by the prior application of PAR-2 activating peptide (AP). The proliferative responses of DLD-1 to tryptase and PAR-2 AP were associated with the phosphorylation of MEK and MAP kinase. Inhibition of MEK by PD98059 completely inhibited the proliferation-enhancing effects of tryptase and PAR-2 AP as well as phosphorylation of MAP kinase. Moreover, tryptase and PAR-2 AP stimulated the production of prostaglandin E2 and the inhibition of prostaglandin synthesis by indomethacin or NS398 resulted in the complete inhibition of the proliferative responses to tryptase and PAR-2 AP. Furthermore, the tryptase-stimulated proliferation of DLD-1 was concentration-dependently inhibited by nafamostat mesilate, a specific inhibitor of tryptase. These results as a whole indicated that tryptase has proliferative effects on DLD-1 through cyclooxygenase- and MAP kinase-dependent manners acting on PAR-2 by its proteolytic activity.

The purpose of this present study was to explore the therapeutic potential of prostaglandins E1 and E2 on the systemic inflammatory response evoked by endotoxin. Since interleukin-18, a monocyte-derived cytokine, is increased during sepsis, decreasing the production of interleukin-18 is important in treating this condition. Prostaglandin E1 and E2 inhibited interleukin-18 production in human monocytes treated with lipopolysaccharide and prostanoid IP-, EP2- and EP4-receptor agonists mimicked the effects of prostaglandins E1 and E2. Therefore, prostanoid IP, EP2- and EP4-receptors might be involved in the decrease in interleukin-18 production during sepsis.

BACKGROUND: Prostaglandin E2 (PGE2) is known to modulate immune responses and is widely viewed as a general immunosuppressant. There have been recognized four receptors for PGE2 (EP1-EP4 receptor) so far, and EP2 and EP4 receptors are mainly involved in the immunosuppressive effect of PGE2 in vitro. In the present study we examined the in vivo immunosuppressive effects of selective EP receptor agonists using a high-responder rat skin transplantation model. MATERIALS AND METHODS: Skin allografts from ACI donors were transplanted onto LEW recipients. Agents were injected everyday between day 0 and day 5 after skin transplantation at the dose of 300 microg/kg subcutaneously. Survival of the skin allograft, histological changes and changes of the intragraft cytokine expressions were analyzed using the reverse transcription polymerase chain reaction (RT-PCR). We also assessed the mixed lymphocyte reaction (MLR) assay using splenocytes. RESULTS: PGE2 significantly prolonged allograft survival (18.8+/-1.5 days) compared with untreated control (14.8+/-0.8 days). EP2R+EP3R+EP4R agonists also prolonged allograft survival (18.0+/-1.0 days) although EP3R agonist or EP2R+EP4R agonists alone failed (15.5+/-0.7, 15.4+/-1.3 days, respectively). RT-PCR analysis in the skin grafts demonstrated IL-10 up-regulation and IFN-gamma down-regulation in all groups except untreated control and EP2R agonist-treated groups. MLR was significantly reduced in groups of EP2R+EP4R agonists, EP2R+EP3R+EP4R agonists and PGE2, compared with untreated control. CONCLUSIONS: The effect of PGE2 to prolong the survival of skin transplant requires the action of a combination of three receptors, i.e., EP2+EP3+EP4.

The effect of prostaglandins E1 and E2 on the 1 ng/ml lipopolysaccharide-induced expression of intercellular adhesion molecule (ICAM)-1, B7.1, B7.2, CD40 and CD40 ligand (CD40L) on monocytes was examined. Prostaglandin E1 suppressed B7.1 and CD40 expression, but prostaglandin E2 did not effect on any type of adhesion molecule expression. Both prostaglandins inhibited tumor necrosis factor (TNF)-alpha production and T-cell proliferation of lipopolysaccharide-treated human peripheral blood mononuclear cells (PBMC). Among prostaglandin E1 receptors (IP/EP1/EP2/EP3/EP4) agonists, ONO-1301, a prostanoid IP-receptor agonist, prevented B7.1 and CD40 expression. ONO-AE1-259-01 a prostanoid EP2-receptor agonist, ONO-AE1-329, a prostanoid EP4-receptor agonist, and ONO-1301 inhibited TNF-alpha production and T-cell proliferation. Moreover, anti-B7.1 and anti-CD40 Abs prevented lipopolysaccharide-induced TNF-alpha production and T-cell proliferation. Therefore, the effect of prostaglandin E1 on TNF-alpha production and T-cell proliferation might depend on the inhibition of B7.1 and CD40 expression, but that of prostaglandin E2 might be independent of adhesion molecules expression. In conclusion, the mechanism responsible for the effect of prostaglandin E1 on lipopolysaccharide-induced responses is distinct from that of prostaglandin E2.

Prostaglandin E1 (PGE1) has therapeutic value for transplantations due to its microvascular activity. Interleukin (IL)-18, which is elevated in plasma during the acute rejection after organ transplantation, elicits the expression of intercellular adhesion molecule (ICAM)-1, B7.1, B7.2, CD40, and CD40 ligand (CD40L) on monocytes as well as the production of interferon (IFN)-gamma and IL-12 and proliferation of T-cells during the human mixed lymphocyte reaction (MLR) in an in vitro model of acute rejection. In contrast, PGE1 inhibits all the adhesion molecule expression, cytokine production and T-cell proliferation in the presence of IL-18. The effects of PGE1 depend on stimulation of the IP/EP2/EP4-receptor, and thus, PGE1 might have therapeutic potential for treating acute rejection due to its immune regulatory effect.

A novel, proinflammatory cytokine, interleukin (IL)-18 production was detected in the medium of human monocytes treated with 3-hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductase inhibitors, pravastatin, and fluvastatin (0.1 and 1 muM) but not with the statin-derived lymphocyte function-associated antigen-1 (LFA-1) inhibitor LFA703, which did not inhibit HMG-CoA reductase. Pravastatin and fluvastatin also induced the production of IL-18, tumor necrosis factor alpha (TNF-alpha) and interferon-gamma (IFN-gamma) in human peripheral blood mononuclear cells (PBMC) in contrast to LFA703. IL-18 production by PBMC is located upstream of the cytokine cascade activated by these statins. The IL-18-induced cytokine production was demonstrated to be dependent on adhesion molecule expression on monocytes. In the absence and presence of lower concentrations (0.1 and 1 ng/ml) of IL-18, pravastatin and fluvastatin inhibited the expression of intercellular adhesion molecule (ICAM)-1 and induced the expression of CD40, whereas LFA703 had no effect. In the presence of higher concentrations (5, 10, and 100 ng/ml) of IL-18, pravastatin, fluvastatin, and LFA703 similarly inhibited the expression of ICAM-1 and CD40 as well as the production of IL-12, TNF-alpha, and IFN-gamma in PBMC. The effects of pravastatin and fluvastatin but not LFA703 were abolished by the addition of mevalonate, indicating the involvement of HMG-CoA reductase in the action of pravastatin and fluvastatin. Thus, the effects of LFA703 were distinct from those of pravastatin and fluvastatin in the presence of lower concentrations of IL-18. It was concluded that LFA703 has the inhibitory effect on an IL-18-initiated immune response without any activation on monocytes.

The interleukin (IL)-18 level in plasma is elevated during the acute rejection after organ transplantation. IL-18 elicits adhesion molecule expression as well as interferon-gamma/IL-12 production and T-cell proliferation in the human mixed lymphocyte reaction, an in vitro model of acute rejection. We examined whether antibodies (Abs) against intercellular adhesion molecule (ICAM)-1, B7, CD40, and CD40, ligand (CD40L) affect the cytokine production and T-cell proliferation. Anti-ICAM-1 and B7 Abs suppressed the cytokine production, while all Abs inhibited T-cell proliferation. ICAM-1 and B7 as well as CD40 may play different roles in the acute rejection.

The activation of T cells plays a role in antitumor response. Monocytes activate T cells by inducing the cell-to-cell interaction that involves the engagement of adhesion molecules with their ligands, and the production of IL-18. The authors examined the effect of the quinazoline-based alpha1-adrenergic receptor antagonists bunazosin, doxazosin, prazosin, and terazosin on the expression of adhesion molecules such as ICAM-1, B7.1, B7.2, CD40, and CD40L on monocytes isolated from human peripheral blood motionuclear cells. Doxazosin, prazosin, and terazosin induced the expression of ICAM-1 and CD40 but had no effect on the expression of B7.1, B7.2, and CD40L. Moreover, IL-18 was detected in the medium of incubated monocytes treated with doxazosin, prazosin, and terazosin. Bunazosin did not affect adhesion molecule expression and IL-18 production, suggesting that the chemical structure of quinazoline might not be related to the effect of doxazosin, prazosin, and terazosin. Although caspase-1 inhibitor completely abolished the production of IL-18, anti-IL-18 mAb and caspase-1 inhibitor partially inhibited the increase in ICAM-I and CD40 expression induced by doxazosin, prazosin, and terazosin. Doxazosin, prazosin, and terazosin can induce monocyte activation with a specific pattern of expression of adhesion molecules and IL-18 production, and this may lead to T-cell activation through the cell-to-cell interaction. The activation of T cells induced by the increase of the expression of ICAM-1 and CD40 and the production of IL-18 may be involved in the anti-cancer effects of doxazosin, prazosin, and terazosin.

Proteinase-activated receptor-2 (PAR-2) has been demonstrated to be highly expressed in the gastrointestinal tract. In the present minireview, we summarize the effects of PAR-1 and PAR-2 stimulation using their activating peptides and agonist proteinases on the calcium signaling and the cell proliferation in DLD-1 cell, a human colon cancer cell line. PAR-2 but not PAR-1 stimulation induced the enhancement of cell proliferation, whereas both PAR-1 and PAR-2 stimulation induced the transient increase in [Ca(2+)](i). PAR-2 stimulation induced the phosphorylation of MEK1/2 and ERK1/2, but PAR-1 stimulation did not. The inhibition of MEK1/2 by PD98059 completely abolished the proliferative response to PAR-2 stimulation. Thus, MEK-ERK activation plays major role in the PAR-2-mediated proliferative response. The coupling of PARs to calcium signaling and MEK-ERK activation may be independent, and varied dependent on cell types.

We examined the effects of beta2-adrenergic receptor (beta2-AR) agonists on the expression of co-stimulatory molecules on lipopolysaccharide (LPS)-stimulated human peripheral blood mononuclear cells. The study found that beta2-AR agonists inhibited the expression of intercellular adhesion molecule-1 (ICAM-1), CD40 and CD14 on monocytes, and that AR agonist activity was antagonized by the selective beta2-AR antagonist, butoxamine. The selective beta2-AR agonists salbutamol and terbutaline induced a similar co-stimulatory molecule expression pattern. The LPS-induced production of tumour necrosis factor-et was inhibited by AR agonists, and this was also antagonized by butoxamine, and mimicked by salbutamol and terbutaline. The AR agonists also inhibited T-cell proliferation through beta2-AR stimulation. This study clearly demonstrated that endogenous catecholamines elicited immunosuppressive effects through beta2-AR stimulation, possibly due to down-regulation of the expression of ICAM-1, CD40 and CD14 on monocytes. These results suggested that the sympathetic nervous system might regulate the T-helper cell balance via the peripheral end-effectors of the stress system.

BACKGROUND & AIMS: Inducible histamine and histamine H2-receptors have been suggested to be involved in innate immune response. METHODS: We examined a functional role of inducible histamine in the protection against hepatic injury and lethality in Propionibacterium acnes -primed and lipopolysaccharide-induced hepatitis, using histidine decarboxylase knockout and H2-receptor knockout mice. RESULTS: Lipopolysaccharide challenge after Propionibacterium acnes priming increased histidine decarboxylase activity in the liver of wild-type mice, associated with a marked elevation of histamine turnover. Histidine decarboxylase-like immunoreactivity was observed in CD68-positive Kupffer cells/macrophages. Treatment of wild-type mice with famotidine or ranitidine but not d -chlorpheniramine augmented hepatic injury and inhibited the survival rate significantly. The same dose of Propionibacterium acnes and lipopolysaccharide induced severe hepatitis and high lethality in histidine decarboxylase knockout and H2-receptor knockout mice; the former were rescued by the subcutaneous injection of histamine. Immunohistochemical study supported the protective role of histamine against the apoptosis of hepatocytes. Histamine suppressed the expression of IL-18 and tumor necrosis factor alpha in the liver, leading to the reduced plasma levels of cytokines including IL-18, TNF-alpha, IL-12, IFN-gamma, and IL-6. CONCLUSIONS: These findings as a whole indicated that endogenously produced histamine in Kupffer cells/macrophages plays a very important role in preventing excessive innate immune response in endotoxin-induced fulminant hepatitis through the stimulation of H2-receptors.

Lipopolysaccharide (LPS) is an inducer of interleukin (IL)-18, which in turn plays important roles in immune responses. Previously, we reported that tumor necrosis factor (TNF)-alpha production could be detected in human peripheral blood mononuclear cells (PBMCs) treated with relatively low concentration of LPS (1 ng/ml), but that same concentration of LPS could not induce IL-18 production. In the present study, we found that LPS at relatively high concentrations (10-1000 ng/ml) induced IL-18 production in a concentration-dependent manner both in monocytes isolated from PBMC, and that histamine (10(-7) to 10(-4) M) inhibited IL-18 production induced by LPS. The studies using receptor subtype-selective agonists and antagonists suggested that the effect of histamine was mediated by H2 receptor but not by H1, H3 and H4 receptors. Therefore, the stimulation of H2 receptor might be beneficial in the treatment of sepsis through inhibiting LPS-elicited IL-18.

Endogenous catecholamine, epinephrine and norepinephrine, and isoproterenol concentration-dependently induced the production of interleukin (IL)-18, tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma, and inhibited that of IL-10 in human peripheral blood mononuclear cells (PBMC). All responses by these stimulations were antagonized by the selective beta 2-adrenergic receptor (AR) antagonist, butoxamine, but not by alpha 1-, alpha 2- and beta 1-AR antagonists. The selective beta 2-AR agonists, salbutamol and terbutaline, induced a similar pattern of cytokine production, indicating that the effect of these AR agonists on cytokine production was through beta 2-AR stimulation. Anti-IL-18 Ab or caspase-1 inhibitor prevented all increase/decrease effects, suggesting that IL-18 might affect the production of all other cytokines. While endogenous IL-18 produced by salbutamol and terbutaline reached a sufficient concentration to induce IL-12 production, these beta 2-AR agonists did not induce the production of IL-12 at all. Epinephrine/norepinephrine/isoproterenol/beta 2-AR agonists increased the production of IL-18 in monocytes, but had no effect on IL-12, TNF-alpha, IFN-gamma and IL-10 production. The lack of beta 2-AR-induced effect on IL-12 production was due to a beta 2-AR-induced inhibition of an IL-18-elicited upregulation of both CD40 and CD40 ligand (CD40L/CD154) expressions on monocytes. The sympathetic innervating lymphoid organs may be under the control of beta2-AR stimulation, maintaining the basal cytokine environment in the tissues.

Prostaglandin (PG) E(2) induces dendritic cell maturation in cooperation with proinflammatory cytokines [such as tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta]. To clarify the involvement of E-prostanoid (EP) receptors in the effect of prostaglandin E(2) on human monocyte-derived dendritic cell (MoDC) maturation, we examined the effect of four types of EP receptor-selective agonists on MoDC maturation. PGE(2) as well as 11,15-O-dimethyl prostaglandin (E(2)ONO-AE1-259-01) (EP2 receptor agonist) and ONO-AE1-329 (EP4 receptor agonist) concentration dependently enhanced the expression of CD80, CD86, CD83, and HLA-DR on MoDCs during maturation, especially in the presence of TNF-alpha, whereas 17S-2,5-ethano-6-oxo-17,20-dimethyl prostaglandin E(1) (EP1 receptor agonist) and 16S-9-deoxy-9beta-chloro-15-deoxy-16-hyfroxy-17,17-trimethylene-19,20-didehydro prostaglandin F(2) (EP3 receptor agonist) showed no effect. The maximal effect of ONO-AE1-259-01 was higher than that of ONO-AE1-329; however, the stimulation with ONO-AE1-259-01 was less effective than that with PGE(2). Simultaneous stimulation with both EP receptor agonists produced additive effects and 11-deoxy-PGE(1) (EP2/EP4 receptor mixed agonist) mimicked the effects of PGE(2). Dibutyryl cAMP mimicked the effects of PGE(2), indicating the mediation of PGE(2) action by cAMP. Matured MoDCs induced by PGE(2) or EP2 and/or EP4 receptor agonists showed a decrease in lipopolysaccharide (LPS)-stimulated IL-12p70, IL-6, and IL-10 production. The coculture of naive T cells with matured MoDCs induced under different conditions showed that EP2/EP4-stimulated MoDCs preferentially induced alloresponsive helper T (Th)2 cells. Together, it was concluded that the cooperative stimulation of EP2 and EP4 receptor subtypes by PGE(2) promoted MoDC maturation and inhibited LPS-induced cytokine production in MoDCs. The matured MoDCs under such conditions preferably induced Th2 polarization, indicating the importance of EP2 and EP4 receptors in the determination of Th1/Th2 development of naive T cells.

Objective and Design: Carboxymethylcellulose (CMC) has been considered to be inert and is commonly used as an additive in medicines, foods and cosmetics. However, we experienced a patient who developed an anaphylactic reaction to CMC after an upper gastrointestinal examination using a barium meal containing CMC. Therefore., we examined the incidence of sensitization by CMC in healthy subjects, and categorized the high risk group prone to developing anaphylactic response to CMC. Methods: An ELISA for detecting CMC-specific IgE antibody was developed using serum from the patient as a positive control. In the ten subjects exhibiting high anti-CMC IgE among 387 normal populations, histamine release from isolated leukocytes was performed. Results: Five of ten subjects with a high IgE titer showed a significant CMC-induced histamine release from leukocyte preparations in vitro as observed in the patient, and were classified as high risk group. There was a correlation between sensitization by CMC and that by Japanese cedar pollen. The incidence of sensitization in females was 2.4 fold higher than that in males. Conclusions: The combination of ELISA and histamine release experiment made it possible to identify the high risk group for developing anaphylactic response. The administration of high dose CMC as a suspending agent in barium sulfate or injectable corticosteroids to this group should be avoided to prevent anaphylactic reactions in the clinic.

BACKGROUND: The plasma interleukin (IL)-18 level is elevated in acute rejection after organ transplantation. Although beta2-adrenergic receptor (AR) agonists suppress the rejection of organ and tissue transplants, little is known about their action mechanisms. We examined the effects of endogenous catecholamines and beta2-AR agonists on the expression of intercellular adhesion molecule (ICAM)-1, B7.1, B7.2, CD40, and CD40 ligand (CD40L) in human mixed lymphocyte reaction (MLR) and in an in vitro model of acute rejection in the presence or absence of IL-18. METHODS: ICAM-1, B7.1 B7.2, CD40, and CD40L expression on monocytes was measured by flow cytometry, and the production of interferon (IFN)-gamma and IL-12 was determined by enzyme-linked immunosorbent assay. Lymphocytes proliferation in MLR was measured by [3H]-thymidine uptake. The relevant AR subtypes were characterized using subtype-selective agonists and antagonists. RESULTS: beta2-AR agonists inhibited the expression of ICAM-1 and CD40 during MLR in the absence of IL-18. Among IL-18-induced expression of ICAM-1, B7.1, B7.2, CD40, and CD40L, beta2-AR agonists inhibited ICAM-1 and CD40 expression. beta2-AR agonists prevented the production of IFN-gamma and IL-12 in the presence of IL-18 but had no effect in the absence of IL-18. beta2-AR agonists inhibited lymphocyte proliferation in IL-18-treated MLR. CONCLUSIONS: We found that beta2-AR agonists strongly inhibited the expression of ICAM-1 and CD40, irrespective of the presence or absence of IL-18, which is different from that of histamine and prostaglandin E2.

Co-stimulatory molecules play important roles in immune responses. We investigated the effect of Bu-Zhong-Yi-Qi-Tang (TJ-41) on the expression of intercellular adhesion molecule-1 (ICAM-1), B7.1 and B7.2 by peripheral blood mononuclear cells stimulated by interleukin-18 (IL-18) using fluorescence-activated cell sorter analysis. TJ-41 increased IL-18-induced ICAM-1 and B7.2 expression, resulting in enhanced production of tumour necrosis factor-alpha and interferon-gamma. These results suggest that TJ-41 enhances IL-18-induced cell-mediated immunity and may enhance host defence mechanisms against pathogens.

In the present study, we examined the effects of prostaglandin E1 (PGE1) on the expression of intercellular adhesion molecule (ICAM)-1, B7.1, B7.2, CD40, and CD40 ligand (CD40L) on peripheral blood mononuclear cells (PBMC) using fluorescence-activated cell sorting analysis as well as its effects on cytokine production using enzyme-linked immunosorbent assay. Whereas no inhibitor of spontaneous expression of adhesion molecules was reported, we found that PGE1 inhibited spontaneous ICAM-1, B7.2, and CD40 expression on monocytes in a concentration-dependent manner but had no effect on the expression of B7.1 and CD40L. Although interleukin (IL)-18 induced the expression of ICAM-1, B7.2, CD40, and CD40L, PGE1 prevented IL-18-induced expression of ICAM-1, B7.2, and CD40. We examined the involvement of five subtypes of PGE1 receptors (IP, EP1, EP2, EP3, and EP4) in the effect of PGE1 on the expression of these adhesion molecules using subtype-specific agonists. Among EP receptor agonists, EP2 and EP4 receptor agonists inhibited IL-18-elicited ICAM-1, B7.2, and CD40 expression. ONO-1301 (IP receptor agonist) prevented the expression of ICAM-1, B7.2, and CD40 regardless of the presence of IL-18 with the same potency as PGE1. The effect of a combination of ONO-1301 and 11-deoxy (D)-PGE1 (EP2/EP4 receptor agonist) on ICAM-1, B7.2, and CD40 expression mimicked that of PGE1. Moreover, PGE1 inhibited the production of IL-12 and interferon-gamma in PBMC in the presence and absence of IL-18, whereas PGE1 induced IL-10 production. In conclusion, IP receptor and EP2/EP4 receptor play an important role in the action of PGE1 on the expression of adhesion molecules on monocytes and cytokine production.

Lipopolysaccharide (LPS) binds to LPS-binding protein (LBP) in plasma and is delivered to the cell surface receptor CD14 on human monocyte. LPS is transferred to the transmembrane signaling receptor toll-like receptor (TLR) 4. In the present study, the effect of histamine on the expression of CD14 on human monocytes was investigated. Histamine concentration- and time-dependently decreased the expression of cell surface CD14, whereas histamine did not decrease mRNA for CD14 nor increase soluble CD14 (sCD14). The inhibitory effects of histamine on CD14 expression were antagonized by H2-receptor antagonist, but not by H1 and H3/H4 antagonist. The effects of selective H2-receptor agonists, 4-methylhistamine and dimaprit, on CD14 expression mimicked that of histamine indicating that histamine regulated CD14 expression through the stimulation of H2-receptors. The pretreatment with histamine partially inhibited the LPS-induced TNF-alpha production in human peripheral blood mononuclear cells (PBMC). Such inhibition might be due to the down-regulation of CD14 expression on monocytes by histamine.

BACKGROUND: The elevation of plasma interleukin (IL)-18 levels and the expression of intercellular adhesion molecule (ICAM)-1 and B7 on monocytes are involved in acute rejection. Prostaglandin (PG) E2 suppresses the rejection in animal transplantation models; however, little is known about its action mechanism. We examined the effect of PGE2 on the expression of ICAM-1 and B7 in the human mixed leukocyte reaction (MLR) in the presence or absence of IL-18. METHODS: We measured the expression of ICAM-1, B7.1, and B7.2 on human monocytes by flow cytometry and determined the associated production of interferon-gamma and IL-12 by enzyme-linked immunosorbent assay. The modulatory effects of PGE2 and the relevant PGE2 receptor subtypes were characterized pharmacologically. RESULTS: PGE2 inhibited the expression of ICAM-1, B7.1, and B7.2 on monocytes in MLR in a concentration-dependent manner. Whereas IL-18 significantly induced the expression of ICAM-1, B7.1, and B7.2 on monocytes in MLR and the production of interferon-gamma and IL-12, PGE2 inhibited these IL-18-initiated enhancements. The effects of PGE2 were mimicked by selective EP2 and EP4 agonists, but not by EP1 and EP3 agonists. CONCLUSION: PGE2 strongly inhibited MLR with respect to the expression of ICAM-1, B7.1, and B7.2 via the EP2 and EP4 receptors, irrespective of the presence or absence of IL-18. In the previous study, histamine inhibited ICAM-1 expression in the presence of IL-18 but had no effect in the absence of IL-18. These results indicate that the inhibitory effect of PGE2 may be more general and stronger than that of histamine and may play an important role in future immunosuppressive strategies.

Vascular smooth muscle cell (SMC) hyperplasia is known to be an important component in the pathogenesis of arteriosclerosis and restenosis. Although heparin has been well recognized as the representative molecule suppressing SMC growth in vitro, attempts to use heparin as a therapeutic anti-restenosis drug have not favorably influenced the angiographic or clinical outcome after angioplasty in some clinical trials. In this study, we have examined the effect of histidine-rich glycoprotein (HRG), a relatively abundant serum glycoprotein (~100 micrograms/ml in human serum), on the growth inhibition of cultured vascular SMC by heparin. Vascular SMC growth was significantly inhibited by heparin, giving nearly 85% inhibition with 100 micrograms/ml heparin. HRG reversed heparin-induced SMC growth inhibition in a dose dependent manner; 75% restoration of cell growth was observed when 100 micrograms/ml of HRG was co-added with 100 micrograms/ml heparin. Interestingly, micromolar concentrations of the zinc ion (0-10 microM), compatible with concentrations released from activated platelets, were found to enhance the restorative action of HRG. Western blot experiment demonstrated no significant amounts of the HRG moiety in fetal bovine serum, eliminating the possible contribution of contaminant HRG from culture media. These findings indicate that HRG, in combination with the zinc ion, plays a role in modulating the SMC growth response in pathophysiological states and explain the lack of success of heparin as a therapeutic anti-restenosis drug in clinical trials.

Histidine-rich glycoprotein (HRG) is a serum protein with possible pluripotent activities. In this study, a method for the quantification of rabbit histidine-rich glycoprotein (rHRG) was developed based upon the high affinity binding profile of rHRG to nickel-nitrilotriacetic acid (Ni-NTA), an improved chelation agent. When the binding profile of Ni-NTA for whole serum proteins was assessed by Western blotting, Ni-NTA exhibited the binding specificity only to rHRG even after washing with 20 mM imidazole, owing to the unusual amounts of histidine residues in rHRG. In the following experiments, the rHRG immobilized onto a microplate with specific antibody was determined spectrophotometrically with peroxidase-labeled Ni-NTA. This method permitted evaluation of rHRG concentrations ranging from 1.0 to 100 ng/ml, and was actually applicable to the monitoring of rHRG in Resource Q-fractionated serum preparations. Also, the co-addition of L-histidine into the incubation mixture significantly diminished the specific binding between rHRG and Ni-NTA. These findings indicate the potential usefulness of this method for the specific measurement of small amounts of rHRG and for understanding the roles of abundant histidine residues in rHRG-metal cation interaction.

Histamine, prostaglandin E(2), and catecholamines have been demonstrated to regulate the innate and acquired immune responses. In this review, we describe one of the mechanisms common to the action of these agonists; the regulation of the expression of costimulatory adhesion molecules such as ICAM-1 and B7 antigens on monocytes/macrophages. The specific receptor subtypes involved in the action of each agonist were H(2) for histamine, EP(2)/EP(4) for prostaglandin E(2), and beta(2) for catecholamines, all of which are coupled with adenylate cyclase via Gs protein. The regulation of the expression of adhesion molecules by these agonists in turn leads to the modulation of subsequent cytokine production mediated by cell-cell interaction under different stimuli. Histamine is synthesized in monocytes and T cells by the induction of histidine decarboxylase. The inducible histamine has different dynamics from that in storage granules of mast cells and basophils. Also, noradrenaline appears to be synthesized in lymphocytes. Thus, immune cells can produce histamine, prostaglandins, and noradrenaline by themselves and modulate the cell-cell interaction between monocytes and other cells. Some of the inhibitors of HMG-CoA reductase were shown to bind to the ICAM-1-binding domain of LFA-1, reducing the interaction mediated by ICAM-1/LFA-1. The regulation of interaction mediated by adhesion molecules may provide a new target for controlling inflammatory and immune responses.

Lipopolysaccharide (LPS) is recognized as a key molecule in the pathogenesis of Gram negative sepsis and septic shock. In the present study, we demonstrate that LPS (1-1000 pg/ml) concentration dependently up-regulated the expression of intercellular adhesion molecule (ICAM)-1, B7.1, and B7.2 on human monocytes using fluorescence-activated cell sorting analysis, and that tumor necrosis factor (TNF)-alpha production induced by LPS in peripheral blood mononuclear cells (PBMCs) was inhibited by the addition of antibodies against these adhesion molecules, suggesting the dependence of TNF-alpha production on cell-cell interaction through these adhesion molecules. Moreover, we found that histamine (10(-7)-10(-4) M) concentration dependently inhibited the expression of ICAM-1 and B7.1, but not B7.2 on monocytes induced by LPS. Histamine also inhibited the responses of TNF-alpha production induced by LPS. The modulatory effects of histamine on ICAM-1 and B7.1 expression and TNF-alpha production were all concentration dependently antagonized by famotidine but not by d-chlorpheniramine and thioperamide, and were mimicked by selective H2-receptor agonists but not by H1-, H3-, and H4-receptor agonists, indicating the involvement of H2-receptors in the histamine action. Dibutyryl cAMP down-regulated ICAM-1 and B7.1 expression on monocytes stimulated by LPS, suggesting the mediation by the cyclic adenosine monophosphate-protein kinase A pathway of H2-receptor activation. These results as a whole indicated that histamine via H2-receptor inhibited the LPS-induced TNF-alpha production through the regulation of ICAM-1 and B7.1 expression, leading to the reduction of innate immune response stimulated by LPS.

beta-Adrenergic receptor (AR) agonists have been demonstrated to modulate the production of inflammatory mediators. Recent studies implied that beta 2-AR agonists might be useful for chronic inflammatory diseases caused by interleukin (IL)-18. In the present study, we found that norepinephrine, epinephrine, or isoproterenol down-regulated IL-18 (100 ng/ml)-induced intercellular adhesion molecule (ICAM)-1 expression on monocytes in a dose-dependent manner (10(-8)-10(-4) M), but did not effect B7.1 and B7.2 expression after 24-h incubation. The modulatory effect of these catecholamines on ICAM-1 expression was antagonized by beta 2-AR antagonist, but not by alpha 1-, alpha 2-, or beta 1-AR antagonist. beta 2-AR-selective agonists salbutanol and terbutaline down-regulated IL-18-induced ICAM-1 expression on monocytes, but alpha 1-, alpha 2-, or beta1-AR agonist had no effect. In the same manner, salbutanol and terbutaline as well as norepinephrine, epinephrine, and isoproterenol regulated the IL-18-induced cytokine production, including IL-12, tumor necrosis factor-alpha or interferon-gamma through the stimulation of beta 2-AR. Together with the previous finding that ICAM-1/lymphocyte function-associated antigen-1 interaction plays a crucial role in the IL-18-initiated cytokine network, the present study strongly suggested that the stimulation of beta 2-AR inhibited the IL-18-activated cytokine cascade through the inhibitory effect on ICAM-1 expression, contributing to finding a new method for clinical treatment.

Cross-linking of the B cell antigen receptor (BCR) with an anti-IgM antibody has been shown to induce dramatic apoptosis in type I Burkitt's lymphoma (BL) cells. However, the apoptotic mechanism triggered via BCR remains unknown. Here we reports a mechanism of BCR ligation-induced apoptosis involving protein phosphatase calcineurin and its specific substrate, transcriptional factor NF-AT. In response to BCR cross-linking, endogenous calcineurin was rapidly activated, and this facilitated nuclear translocation of NF-ATc2, a subtype of NF-AT members. Interestingly, nuclear-imported NF-ATc2 functioned pro-apoptotically in BL cells. The effect of NF-ATc2 was efficiently blocked with FK506, which prevented its nuclear translocation through inactivation of calcineurin. In addition, TR3 induction during BCR cross-linking was reduced by FK506 and the VIVIT peptide, which is a highly selective inhibitor for NF-AT. This strongly suggests that activation of NF-ATc2 by calcineurin is essential for TR3 recruitment, and that TR3 can be considered as a candidate for death effector in BCR-mediated apoptosis. Therefore, NF-ATc2 plays a crucial role in BCR-mediated apoptosis in type IBL, providing greater insight into unique BL characteristics through BCR signaling.

BACKGROUND: Interleukin (IL)-18 was identified as an interferon (IFN)-gamma-inducing factor and was demonstrated to up-regulate the expression of intercellular adhesion molecule (ICAM)-1 on human monocytes. In organ transplantation, elevation of plasma IL-18 levels has been reported during acute rejection. In the present study, we examined the effect of IL-18 on human mixed lymphocyte reaction (MLR), an in vitro model of acute rejection after organ transplantation. We also investigated the modulatory effects of histamine on IL-18 action because histamine has been demonstrated to be a modulator of IL-18 effect and a mediator of inflammation. METHODS: We measured the expression of ICAM-1 on human monocytes in MLR in the presence or absence of IL-18 by flow cytometer and determined the associated production of IFN-gamma and IL-12 by ELISA. The modulatory effects of histamine and the relevant histamine receptor subtypes were characterized pharmacologically. RESULTS: The expression of ICAM-1 on monocytes in MLR was markedly enhanced by the addition of IL-18 in a concentration- and time-dependent manner. In parallel to ICAM-1 up-regulation, IL-18 significantly enhanced the production of IFN-gamma and IL-12 in MLR. Histamine concentration-dependently inhibited ICAM-1 expression and cytokine production in MLR stimulated with IL-18, whereas histamine alone did not show any effects on these responses in the absence of IL-18. The effects of histamine on both ICAM-1 expression and cytokine production were mimicked by the selective H2-receptor agonists 4-methylhistamine and dimaprit and were antagonized by the H2-receptor antagonist famotidine but not by H1- and H3-receptor antagonists. CONCLUSION: IL-18 strongly enhanced human MLR with respect to ICAM-1 expression and cytokine production. The fact that histamine could inhibit the IL-18-stimulated MLR implies that immunomodulation by histamine and selective H2-receptor agonists may have an important role in future immunosuppressive strategies.

Costimulatory molecules play important roles in immune responses. In the present study we investigated the effects of PGE(2) on the expression of ICAM-1, B7.1, and B7.2 on monocytes in IL-18-stimulated PBMC using FACS analysis. Addition of PGE(2) to PBMC inhibited ICAM-1 and B7.2 expression elicited by IL-18 in a concentration-dependent manner. We examined the involvement of four subtypes of PGE(2) receptors, EP1, EP2, EP3, and EP4, in the modulatory effect of PGE(2) on ICAM-1 and B7.2 expression elicited by IL-18, using subtype-specific agonists. ONO-AE1-259-01 (EP2R agonist) inhibited IL-18-elicited ICAM-1 and B7.2 expression in a concentration-dependent manner with a potency slightly less than that of PGE(2), while ONO-AE1-329 (EP4R agonist) was much less potent than PGE(2). The EP2/EP4R agonist 11-deoxy-PGE(1) mimicked the effect of PGE(2) with the same potency. ONO-D1-004 (EP1R agonist) and ONO-AE-248 (EP3R agonist) showed no effect on IL-18-elicited ICAM-1 or B7.2 expression. These results indicated that EP2 and EP4Rs were involved in the action of PGE(2). Dibutyryl cAMP and forskolin down-regulated ICAM-1 and B7.2 expression in IL-18-stimulated monocytes. As EP2 and EP4Rs are coupled to adenylate cyclase, we suggest that PGE(2) down-regulates IL-18-induced ICAM-1 and B7.2 expression in monocytes via EP2 and EP4Rs by cAMP-dependent signaling pathways. The fact that anti-B7.2 as well as anti-ICAM-1 Ab inhibited IL-18-induced cytokine production implies that PGE(2) may modulate the immune response through regulation of the expression of particular adhesion molecules on monocytes via EP2 and EP4Rs.

Interleukin (IL) 18, a powerful inducer of the immunoregulatory cytokine interferon-gamma (IFN-,gamma), presents upstream of the cytokine activation cascade in the inflammatory response. The anti-inflammatory properties of steroids permit their use in various conditions, although effects are transient and pathological states are not fully relieved by short-term steroidal use. We examined the effect of lipopolysaccharide (LPS)/IL-2 on the cytokine cascade in human peripheral blood mononuclear cells (PBMCs). We also examined the effect of steroids on LPS/IL-2-induced cytokine production in human PBMCs taken from healthy volunteers. Cell-free supernatant fractions were assayed for IL-18, IL-12, IL-2, IFN-,gamma and IL-10 protein, using enzyme-linked immunosorbent assays, and synergy between LPS and IL-2 in enhanced production of IL-18 was observed. Steroids suppressed the production of IL-18 and other secondary cytokines in LPS/IL-2-stimulated PBMCs, in a concentration- and time-dependent manner, although inhibition was incomplete even at high concentrations. Effects of steroid treatment on expression of membrane-bound LPS receptor antigen (mCD14) and intercellular adhesion molecule-1 (ICAM-1) in PBMCs were studied by flow cytometric analysis. Steroid treatment up-regulated mCD14 expression in a concentration-dependent manner, with no effect on ICAM-1 expression. These results suggest that the incomplete counteraction of steroids in the LPS/IL-2-initiating cytokine cascade is due, at least partly, to the up-regulation of mCD14 by steroid preparations, which increases susceptibility to bacterial endotoxins.

IL-18 (0-100 ng/ml) specifically upregulated ICAM-1 expression on monocytes in human PBMC as demonstrated in our previous study. In the present study, we examined whether the synergistic upregulation of ICAM-1 occurred after the stimulation with the combination of IL-18 and IL-12 and whether the synergistic production of IFN-gamma was dependent on the interaction between ICAM-1 on monocytes and LFA-1 on NK/T cells. The effect of IL-12 on ICAM-1 expression on monocytes was marginal even at the highest concentration (100 ng/ml). However, in the presence of IL-12 (100 ng/ml), the expression of ICAM-1 induced by IL-18 was significantly enhanced as compared with that obtained by IL-18 alone. In addition to the expression of ICAM-1 on monocytes, IFN-gamma production was synergistically stimulated by IL- 18 and IL-12. Anti-ICAM-1 and anti-LFA-1 Abs exhibited significant inhibitory effect on enhanced production of IFN-gamma by the combination of two cytokines, in particular, anti-ICAM-1 showing the complete inhibition. These results as a whole indicated that synergistic effect of IL-18 and IL-12 on IFN-gamma production in human PBMC is ascribed to the synergism of the effect of two cytokines on ICAM-1 expression on monocytes and that the subsequent ICAM-1/LFA-1 interaction plays an important role in the enhanced production of IFN-gamma.

In the previous study, we demonstrated that interleukin (IL)-18 up-regulated intercellular adhesion molecule-1 (ICAM-1) expression on monocytes in human peripheral blood mononuclear cells (PBMC) and that heterotypic interaction between monocytes/T or NK cells through ICAM-1/LFA-1 intensified the production of IL-12, interferon-gamma (IFN-gamma), and tumor necrosis factor-alpha (TNF-alpha) in PBMC. In the present study, we demonstrate that histamine inhibited the ICAM-1 expression in monocytes induced by IL-18 using flow cytometry and that the responses of IL-12, IFN-gamma, and TNF-alpha induced by IL-18 were concentration dependently inhibited by coexisting histamine, whereas IL-18-inhibited IL-10 production was reversed by the same concentrations of histamine. The modulatory effects of histamine on ICAM-1 expression and cytokine production were all concentration dependently antagonized by famotidine but not by d-chlorpheniramine and thioperamide, and were mimicked by selective H(2)-receptor agonists but not by H(1)- and H(3)-receptor agonists, indicating the involvement of H(2)-receptors in histamine action. The inhibition of IL-18-induced IFN-gamma by histamine was ascribed to the strong inhibition of IL-12 production by histamine. Histamine thus operates the negative feedback mechanism against IL-18-activated cytokine cascade through the strong inhibitory effect on ICAM-1 expression and IL-12 production in monocytes, contributing to the formation of diverse pattern of cytokine activation from Th1 to Th2, depending on the monocyte/macrophage activation and cytokine environment.

Interleukin-18 (IL-18) is a powerful inducer of interferon-gamma (IFN-gamma), a key immunoregulatory cytokine. Cellular immune responsiveness, as measured by IL-18-induced IFN-gamma production from peripheral blood mononuclear cells (PBMCs) in ELISA assay, was evaluated in 10 patients with advanced cancer and in 10 normal controls. Supernatant levels of IFN-gamma were detected at 2 hours after PBMCs culture and markedly increased thereafter in healthy volunteers. In contrast, IFN-gamma production in cancer patients was not detected during the culture period (0-72 hours). We also measured IL-18-stimulated IL-12 production in healthy volunteers and null response was observed in cancer-beating patients. Next, we studied mRNA expressions of IL-18 receptor (IL-18R) and IFN-gamma in PBMCs in cancer patients and healthy volunteers by RT-PCR assay. Both mRNA levels of IL-18R and IFN-gamma were significantly decreased in cancer-beating patients compared with normal controls. These results suggested that IL-18 responsiveness for IFN-gamma production in cancer-beating patients was impaired. Using flow cytometric analysis, we studied T-cell subsets, CD3(-) CD56(+) (NK cell), CD3(+) CD45RO(+) (memory T-cell), CD3(+) CD95(+) (Fas(+) T- cell), CD3(+) CD4(+) (helper T-cell), CD3(+) CD8(+) (cytotoxic T-cell: CTL) and CD3(+) Va24(+) (NKT-cell), in cancer patients and normal controls. The NK and cytotoxic T-cells significantly decreased and NKT-cells had decreased tendency in cancer patients compared with normal controls. In contrast, memory T cells, Fas(+) T-cells and helper T-cells were all significantly increased in cancer patients compared with normal controls. These results suggested that the underlying mechanism of impaired IL-18 responsiveness in PBMCs from cancer-beating patients was, at least in part, ascribed to a drastic decrease of NK cells and CTL which constitutively and highly express IL-18R and also attributed to null Production of IL-12 which up-regulates IL-18R.

Tacrolimus (FK-506) and cyclosporin A (CsA) are calcineurin antagonists used widely as T-cell immunosuppressants; however, their relative efficacy on the production of interleukin-18 (IL -18) remains undefined. We have examined the effects of FK-506 and CsA on the cytokine generation of human peripheral blood mononuclear cells (PBMCs) in mixed lymphocyte reaction (MLR) with lipopolysaccharide (LPS). We studied the levels of interleukin-18 (IL-18), IL-12, IL-10,IL-6,IL-2 and interferon-gamma (IFN-gamma) in the supernatant in allo-MLR by ELISA assay. Supernatant levels of IFN-gamma, IL-2, IL-6, IL-10 and IL-12 were detected 12 h after MLR and markedly increased thereafter. In contrast, production of IL-18 was detected at 12 h, reached a near maximum level at 24 h and decreased at 72 h. These results suggested that IFN-gamma production depended on IL-18, IL-12 and IL-2 in the early phase of MLR and depended mainly on IL-12 and IL-2 in the late phase. Both calcineurin antagonists inhibit the generation of IL-18, which plays a large role in allogeneic cell interactions,in macrophages and they also promote an equivalent down-regulation of T helper 1 (Th1) and Th2 responses in a concentration-dependent manner. About 90% of IFN-gamma production induced by MLR was inhibited by an anti-IL-18 antibody, showing that IL-18 can trigger IFN-gamma production in MLR. These results suggest that dual signaling consisting of antigen-driven nuclear factor of activated T cells (NFAT) activation and LPS-mediated NF-kappaB activation is crucial for IL-18 production in macrophages, and that IL-18 can trigger IFN-gamma production in T-cells by MLR.

Histamine (10(-7) to 10(-4) M) concentration-dependently stimulated the production of IL-18 and IFN-gamma and inhibited the production of IL-2 and IL-10 in human PBMCs, Histamine in the same concentration range did not induce the production of IL-12 at all. The stimulatory or inhibitory effects of histamine on cytokine production were all antagonized by H-2 receptor antagonists ranitidine and famotidine in a concentration-dependent manner, but not by H-1 and H-3 receptor antagonists. Selective H-2 receptor agonists, 4-methylhistamine and dimaprit, mimicked the effects of histamine on five kinds of cytokine production. The EC50 values of histamine, 4-methylhistamine, and dimaprit for the production of IL-18 were 1.5, 1.0, and 3.8 mu M, respectively. These findings indicated that histamine caused cytokine responses through the stimulation of H-2 receptors, All effects of histamine on cytokine responses were also abolished by the presence of either anti-IL-18 Ab or IL-1 beta-converting enzyme/caspase-1 inhibitor, indicating that the histamine action is dependent on mature IL-18 secretion and that IL-18 production is located upstream of the cytokine cascade activated by histamine. The addition of recombinant human IL-18 to the culture concentration-dependently stimulated IL-12 and IFN-gamma production and inhibited the IL-2 and IL-10 production, IFN-gamma production induced by IL-18 was inhibited by anti-IL-12 Ab, showing the marked contrast of the effect of histamine. Thus histamine is a very important modulator of Th1 cytokine production in PBMCs and is quite unique in triggering IL-18 initiating cytokine cascade without inducing IL-12 production.

Background/Purpose: Interleukin-18 (IL-18)/interferon-gamma-inducing factor (IGIF) is a novel proinflammatory cytokine that can induce interferon gamma (IFN-gamma). In addition, IL-18 enhances intracellular adhesion molecule-1 (ICAM-1) expression as well as Fas ligand (FasL) expression, and induces apoptosis in hepatic injury. The aim of this study was to clarify the potential role of IL-18 in the pathogenesis of the progressive inflammation and fibrosis in biliary atresia (BA). Methods: Six children with BA before hepatic portoenterostomy (HPE), 13 with BA including 7 without jaundice and 6 with persistent jaundice after HPE, and 16 healthy controls were examined. Blood samples were obtained preoperatively from 6 patients, after HPE from 13, and after liver transplantation from 4. The IL-18 level was determined by an enzyme-linked immunosorbent assay (ELISA). Immunohistochemically, liver specimens from BA patients were studied using a monoclonal antibody to macrophage-associated antigen (CD68). Results: IL-18 levels were elevated in the patients before HPE compared with those of the controls (349 +/- 54 pg/mL v 138 +/- 13 pg/mL, P < .0001). After HPE, extremely high concentrations of IL-18 were observed in patients with persistent jaundice (532 +/- 95 pg/mL, P < .0001), and the IL-18 levels were significantly high even in the patients without jaundice (249 +/- 29 pg/mL, P < 0.005). The high IL-18 level lasted for a long time even in the patients without jaundice after HPE. In contrast, the IL-18 levels immediately decreased after liver transplantation. Immunohistochemically, the number of CD68-positive Kupffer cells was significantly higher, and the size was larger in the livers of the patients than in the controls. The proliferation of CD68-positive cells was much more conspicuous in the liver specimens obtained during liver transplantation than in those at the time of HPE. Conclusions: Our findings showed elevation of serum IL-18 levels and activation of Kupffer cells in BA. IL-18 released from activated Kupffer cells might play an important role in the pathophysiology of the progressive inflammation and fibrosis in BA. Furthermore, IL-18 level may be related to the prognosis in patients with BA. Copyright (C) 2000 by W.B. Saunders Company.

The in vitro mixed lymphocyte reaction (MLR) is a useful model to study alloresponsiveness to histocompatibility antigens. Secretion of different cytokine proteins in the supernatant of allo-MLR cultures has been reported in a few studies. We studied the levels of the cytokines interferon gamma (IFN-gamma) and interleukin-6 (IL-6), IL-10, IL-12, and IL-18 in the supernatant in allo-MLR by ELISA assay. Supernatant levels of IFN-gamma, IL-6, IL-10, and IL-18 were detected at 12 h after MLR and markedly increased thereafter. In contrast, secretion of IL-12 was detected after 48-72 h. These results suggested that IFN-gamma production depended on IL-18 in the early phase of MLR and depended on both IL-18 and IL-12 in the late phase, An antibody (Ab) neutralizing test was also performed. The levels of IFN-gamma were significantly downregulated after the addition of anti-IL-18 Ab, anti-IL-12 Ab, or anti-IFN-gamma Ab, and the levels of IL-12 were significantly downregulated after the addition of anti-IL-12 Ab and anti-IL-18 Ab. Treatment with these Ab did not suppress IL-6 production at all. The two-way MLR show-ed the same tendency as the one-way MLR. These results suggest the importance of IL-18 and IL-12 in allogeneic cell interactions and also suggest the usefullness of these Ab as regulators of alloresponsiveness.

Corticoids are well known for their immunosuppressive properties. Interleukin-10 (IL-10) is an intrinsic antiinflammatory peptide in immune diseases, originally identified as cytokine synthesis inhibitory factor. We examined the effect of hydrocortisone sodium succinate (HSS) on the production of IL-10 by human peripheral blood mononuclear cells (PBMCs). PBMCs from healthy volunteers and cancer-burden patients were preincubated separately with or without HSS for 1 h, then stimulated with 5 mu g/ml lipopolysaccharide (LPS). Production of IL-10 by human PBMCs was detected with LPS stimulation and its production was higher in cancer-burden patients than in normal volunteers, although this was not statistically significant. HSS suppressed production of IL-10 by LPS-stimulated PBMCs in a dose-dependent manner both in normal volunteers and in cancer-burden patients. These results indicate that, in addition to their antiinflammatory properties, corticoids act to restore the immunosuppressive states even in cancer-burden states.

In a search for new biologic serum tumor markers with prognostic value we evaluated the soluble form of the CD30 (sCD30), a marker of cells producing T helper 2 (Th2)-type cytokines, interleukin-1 receptor antagonist (IL-1ra), soluble interleukin-2 receptor (sIL-2R), soluble tumor necrosis factor -type I, -type II (sTNF-R55, -75) and immunosuppressive acidic protein (IAP) in patients with advanced colorectal cancer. The data showed that abnormal levels of sCD30 were detected in eight (80.0%) out of tell patients. In contrast, sCD30 levels were not detected in healthy volunteers. The relationship between sCD30, sIL-2R and ZAP were positively correlated. In contrast, sCD30 and IL-1ra were negatively correlated. These results suggested that IL-1ra may play a role, at least in part, to inhibit CD30 release, and sCD30 appears to be a new biologic serum tumor marker of possible use in the clinical setting of cancer patients.

Intercellular adhesion molecule-1 (ICAM-1, CD54) is a membrane glycoprotein and a member of the immunoglobulin superfamily, It plays a central role I in cell to cell-mediated immune responses and is a ligand for leukocyte function-associated antigen-1 (LFA-1), We report here that a newly discovered, cytokine, interferon-gamma-inducing factor (IGIF) [H, Okamura et al, (1995) Nature 378, 88] recently proposed to be designated as IL-18, selectively up-regulates ICAM-1 expression in KG-1 cells, a human myelomonocytic cell line, in which IL-18 also enhances interferon-gamma production. IL-18 induced heterotypic aggregation bet tween KG-1 and Peer T cells, which was blocked by anti-ICAM-1 and/or LFA-1 antibodies, Anti-interferon-gamma antibody did not block the IL-18-induced up-regulation of ICAM-1 on KG-1 cells. These results thus show that IGIF/IL-18, enhances ICAM-1 expression in KG-l cells in an interferon-gamma-independent pathway, up-regulates ICAM-1 functions, and that IL-18 might play a potential role in immunoregulation by mediating immune cell infiltration into the tissues.

CD30 is a member of the tumor necrosis factor (TNF)/nerve growth factor (NGF) receptor superfamily, which includes other functionally relevant molecules such as CD27, CD40 and Fas. The CD30 molecule comprises membrane bound glycoprotein chains of 105 and 120 kDa. The extracellular portion of CD30 is proteolytically cleaved to produce an 88 kDa soluble form of the molecule (sCD30), which is released by CD30-expressing cells. The elevated levels of sCD30 reflect early and continuous activation and/or death of CD30+ type 2 T cells. sCD30 levels were detected in 8 out of 10 advanced colorectal cancer patients. In contrast, sCD30 levels were not detected in healthy volunteers. The relationship between sCD30, sIL-2R and IAP were positively correlated. In contrast, sCD30 and IL-1ra levels were negatively correlated. In addition, serum IL-1ra levels in patients with advanced cancers were significantly lower than those of healthy controls. These results suggest that IL-1ra may play a role, at least in part, to inhibit CD30 release, and sCD30 appears to be a new biologic serum tumor marker, such as IAP and sIL- 2R, of possible use in the clinical setting of cancer patients.

Interferon-gamma inducing factor (IGIF) is a new cytokine which is thought to be useful clinically as an anti-tumor agent. Fas ligand (FasL) is a type II membrane protein belonging to the necrosis factor family, which induces apoptosis by binding to its counter receptor, Fas. In this paper, we report the effect of IGIF for the expression of Fas and FasL in human healthy peripheral blood lymphocytes (PBLs). IGIF up regulates the expression of Fas and FasL in PBLs.

We report here the time-course of electron microscopic changes induced by gamma-interferon (IFN-gamma) in the human erythromyeloid leukemia cell line K562. In K562 cells treated with IFN-gamma for 6 h, the nuclei were polygonal in shape and microvilli were far more abundant on cell membranes compared with control K562 cells, and invaginations were often seen in the cell membranes. There was a reduction in the number of cell-membrane microvilli and an increase in the number of lysosomal bodies in the cytoplasm of K562 cells treated with IFN-gamma for 12 h. After treatment with IFN-gamma for 24 h, the cell membrane microvilli disappeared, large numbers of cellular organelles were observed, such as mitochondria and lysosomes, and the cytoplasm became electron-dense. Cytoplasmic vesicles and vacuoles were also observed. These vesicles may correspond to an intermediate step in the ultimate cellular disintegration associated with apoptosis caused by IFN-gamma.

Damage-Associated Molecular Patterns(DAMPs)は細胞ストレスに伴い放出される内因性免疫応答調節因子である。過剰なDAMPsの生成は、炎症の遷延化や増悪を促す。慢性炎症性疾患の病変部位では、血管新生を伴うリモデリングが誘導され、病態増悪の本態として考えられている。その機序として、DAMPsと炎症性メディエーターの相互作用によるマクロファージ(MΦ)の過剰な活性化が関与することが示唆されている。本研究では、慢性炎症性病態であるアレルギー性炎症に焦点をあて、その病態形成に関与するDAMPsのInterleukin-33(IL-33)と炎症性メディエーターのヒスタミンによる血管新生に対する影響について解析を行った。 ヒト血管内皮細胞株EA.hy926細胞を用いたin vitro実験系において、ヒスタミンはIL-33の発現量を増加させることを確認した。ヒスタミンによるIL-33発現量の増加作用は、ヒスタミンH1受容体が関与することを明らかにした。 さらに、マトリゲルを用いたin vitro血管新生実験モデルにおいて、ヒスタミンはヒスタミンH1受容体を介して管腔形成を促進させることを見出した。ヒスタミンにより血管内皮増殖因子(vascular endothelial growth factor、VEGF)の発現上昇が認められたが、ヒスタミンによる管腔形成促進作用はVEGF受容体の阻害剤では抑制されなかった。したがって、ヒスタミンはVEGFとは異なる機序を介して血管新生を促進する可能性が示唆された。

恒常性維持機構(ホメオスタシス)を経年変化するホメオダイナミクスとして解析した知見を基に、自家組織による再生・修復促進法の開発が期待される。この開発は、様々な医療の分野にに影響を及ばすのみならず、老年期のQOLの向上といった人類の希求するテーマを解決するものである。一般に、適度な運動負荷が良好な結果をもたらすことは知られているが、これを様々な方法で解析して、根拠あるものとして証明することが大切である。まず、申請者らはそのための実験系を確立できた。適度な運動負荷という曖昧なものではなく、運動の代わりとなる、治療薬候補探索と提案をすることができた。治療薬候補の病態改善効果を検討できた。

脳卒中を自然発症する重症高血圧症動物モデル(SHRSP)を用いて病態進行と骨髄血管性ニッチの動的変化を検討し、骨髄造血系の制御が血管病の治療標的となり得るか検討した。また運動介入が血管性ニッチ改善に寄与するか検討した。発症期の血管性ニッチでは内皮細胞が障害され、幹細胞の生存・保持に重要なSDF-1産生能や低酸素環境の劣化、骨髄球増加とCD34+血球・血管系幹（前駆）細胞の減少を認めた。運動は骨髄内皮細胞と間葉系細胞を維持し、全身性炎症反応を改善し、CD34+細胞の増殖・骨髄内保持と動員を促進した。発症後ニッチ細胞のFGF-2産生が増加し、血管性ニッチ再構築と造血系制御に関与する可能性を示した。

血漿高ヒスチジン糖タンパク（HRG）の炎症病態における肝HRG遺伝子発現、及び、血漿HRGタンパクの抗炎症作用の解析をおこなった。複数種の慢性・急性炎症モデルを用いて肝遺伝子発現を網羅的に解析したところ、HRG遺伝子の発現変動と相関・逆相関する核内タンパク遺伝子を計14種同定した。これら候補遺伝子には、HRGの遺伝子発現を制御する因子が含まれる可能性が高い。また、敗血症モデルの血漿を用いたプロテオーム解析によって、HRGと結合親和性をもつ血漿タンパクを計3種同定した。これら同定タンパクは、すべて炎症病態に関与する因子であり、その炎症応答機序はHRGによって制御される可能性が示唆された。

本研究では、生体内において酸化ストレス除去を担う分子経路のマスター転写因子であるNrf2に着目し、運動器において最も含有量の多い幹細胞である間葉系幹細胞においてその発現調節機序と機能を明らかにすることを目的に研究を行った。加齢組織においては慢性炎症、あるいは転写因子Notch1の減少によりmiR-155が誘導され、C/ebpβの発現が抑制されることでNrf2の発現抑制が生じ、抗ストレス経路の破綻が生じることが明らかとなった。Nrf2には幹細胞の自己複製、エピジェネティック修飾の維持に関わる機能を有することも示唆されたことから、Nrf2は運動機能維持を目指した標的分子になりうると考えられた。

ホメオダイナミクスは、マクロファージの分化・活性化を介する血管内皮細胞の障害と再生・修復で表現される。担い手のDAMPsの内、IL-18やadvanced glycation end product(AGE)、histidine-rich glycoprotein(HRG)、high mobility group box1(HMGB1)に着目し、ホメオダイナミクス破綻状態である組織障害効果と、再生誘導活性を検証した結果、マクロファージの分化・活性化の決定因子ではなく、増強因子であることがわかった。DAMPs濃度は障害範囲に比例し、この活性を制御することはホメオダイナミクス回復に有効である。

敗血症は感染症に伴う重篤な臓器障害の病態であり、世界的に死因の上位を占め続けている。敗血症の新規開発薬物は過去数十年継続されてきたが、有効な薬物は何一つ見出されることがなかった。本研究では、申請者が見出した敗血症時の血漿タンパクHistidine-rich glycoprotein (HRG) の低下を原因とする免疫血栓の形成の機序を解明し、HRGの補充療法が如何にしてその病態を改善するかを明らかにした。敗血症病態に関与する細胞として、好中球や血管内皮細胞に加え、赤血球の重要性を実験データに基づき指摘した。マウスモデルにおいてHRG補充療法は、敗血症性ARDS病態に対し有効である。

第3脳室を囲む視床下部は細分化された核の神経活動を介して全身の生理的恒常性維持と組織再生に関わる。継続的な運動を脳卒中発症ラットにさせると脳傷害後の神経再生に重要な側脳室下帯の神経新生・分化・成熟に加え、第3脳室神経幹細胞候補のtanycyteの自己複製と神経新生・成熟の活性化を認めた。また脳室域のFGF-2とEGF産生が増加した。 脳組織再生には傷害部の骨髄由来血管系幹細胞による血管網の構築が重要である。骨髄幹細胞は骨髄の間葉系細胞と血管内皮細胞やSDF-1などにより維持されるが、脳血管障害時にはこれらの細胞極性と増殖因子の産生が低下した。運動は幹細胞の微小環境を改善し脳傷害の改善に関与する。

外科侵襲に伴う臓器障害は時に致死的になる。この一因として外科侵襲に対する過剰な免疫応答が挙げられている。本研究ではこの免疫応答システムの解析を行い、その制御によって臓器障害の抑制、ひいては予後の改善を目的として研究を行った。 外科侵襲による免疫応答の原因物質であるDAMPsの中のHMGB1に注目した。HMGB1はマクロファージを介して血管新生の制御に関与していると考えられた。このHMGB1の制御により、肝阻血再灌流モデルの予後改善を認めた。これは、肝再生が肝細胞の肥大変化ではなく、肝細胞増殖にシフトすることによるものと考えられた。 HMGB1の制御は術後の阻血再灌流障害を改善させると考えられる。

High mobility group box1(HMGB1)は、免疫応答に大きく関与している。申請者らは、HMGB1が脳梗塞、アテローム性動脈硬化症などの原因因子で、抗HMGB1抗体でこれらを抑制できることを報告した。HMGB1の高血圧症の病態生理への関与はまだ明らかではないので、脳卒中易発症高血圧症自然発症ラット (SHRSP)を用いて検討してきた。血管内皮細胞障害が高血圧症の原因であるが,HMGB1の血管内皮細胞障害は確認出来なかったが、好中球活性化が血管内皮細胞障害を誘導する機序を解明することが出来た。好中球活性化制御因子を特定したので、高血圧症新規治療薬の開発に向けた研究を継続する。

ラット脳硬膜上から加えた液体衝撃により作製した脳外傷では、大脳半球の広範な領域に脳血管の透過性亢進を生じ、脳浮腫が惹起された。受傷局所では神経細胞の核内に局在しているHMGB1が細胞質領域から細胞外に放出された。同領域では、血液脳関門の構造破綻とミクログリア細胞の活性化像ならびに細胞数の増加が認められ、炎症性サイトカインの発現が上昇していた。以上の外傷誘発性の炎症応答は、抗HMGB1抗体の受傷後投与により85％抑制された。HMGB1と結合する生薬甘草中活性成分グリチルリチンは、抗体と類似の作用を示した。同様に、マウスの脊髄損傷モデルで抗HMGB１抗体は運動麻痺症状を著明に改善することができた。

腫瘍細胞株をマウスの背部皮下に移植した担癌マウスに浸透圧ポンプを用いて、抗HMGB1モノクローナル抗体を持続投与したところ、コントロールと比較して抗HMGB1抗体投与群において、有意に腫瘍増殖の抑制が見られた。また、抗HMGB1抗体投与群の腫瘍組織中の新生血管密度がコントロールと比較して有意に減少していた。しかしながら、免疫不全マウスを用いた担癌マウスモデルでは、抗HMGB1抗体に抗腫瘍効果は認められなかったため、抗HMGB1抗体の抗腫瘍効果は直接的な作用ではなく、リンパ球等を介した免疫反応による効果である可能性も示唆された。

本研究では生活習慣病の病態形成に関与するAdvanced glycation end products (AGEs)やHigh mobility group box-1 (HMGB-1)等のReceptor for AGE (RAGE) リガンドが臓器移植における拒絶反応や虚血再灌流障害に及ぼす影響・メカニズムをIn vitroおよびVivoの両面から解析した。その結果、臓器移植におけるRAGEリガンドを介した自然免疫機構による拒絶反応や虚血再灌流障害の制御に向けた研究データの集積を達成し得た。

成体脳の神経幹細胞分化の条件は極めて難しい。運動療法（習慣）の有効性を受け、それを決定する要因として(1)神経幹(前駆）細胞自体の生存と活性、(2)幹（前駆）細胞の成長や分化に関与する炎症性分子や神経栄養因子などの脳内微小環境、(3)傷害後の時間的因子を考え、重症高血圧と脳卒中自然発症性のラットに長期の自発運動をさせ検討した。生存率の延長、神経機能改善は発症後2日目から運動を開始したラットにも認められた。運動により骨髄細胞老化が抑制され、内在性神経幹(前駆）細胞の増加と成長分化が促進された。全身性及び脳局所の炎症反応が抑制され、血管内皮細胞由来NO産生と傷害後早期に神経栄養因子が誘導された。

High mobility group box1(HMGB1)は、壊死細胞核から細胞外へ放出される新規サイトカイン分子である。申請者は、HMGB1を標的とする抗体医薬を発想し、すでにラット中大脳動脈2時間閉塞・再灌流モデルを用いて、抗HMGB1単クローン抗体の劇的な脳梗塞の改善、脳浮腫の抑制作用を明らかにしてきた。虚血再灌流の脳障害に対して、抗HMGB1抗体はBBB構造・機能の保護を中心として多数の炎症応答反応を抑制することで、脳梗塞の進行を止め、脳を保護したことを解明した。

Damage-associated molecular patternであるHigh mobility groupbox-1(HMGB1)は、虚血脳神経細胞や脳外傷局所の神経細胞核から細胞質を経て細胞外へ放出された。放出されたHMGB1は、血管内皮細胞、周皮細胞に働き、収縮性反応を誘導して脳血管透過性を亢進させた。HMGB1由来ペプチドに、低血圧誘導その他の活性を見出した。抗HMGB1単クローン抗体は脳外傷時の脳血管透過性亢進と炎症反応を抑制した。

ラット脳血管内皮細胞、血管周皮細胞、アストログリア細胞からなる試験管内血液-脳関門培養系を用いて、血管透過性に対するHMGB1の効果を検討した。この実験系において、脳側から、昆虫細胞Sf9を使って作製したヒスタグ付きヒト組換え体HMGB1を、1あるいは10・g/ml添加し、上下室間の電気抵抗の変化とエバンスブルー標識ウシ血清アルブミンの漏出を測定したところ、組換え体HMGB1は、濃度依存的に血管透過性を亢進させた。HMGB1のC末端配列を認識する単クローン抗体で予め組換え体HMGB1を処理すると、HMGB1の血管透過性亢進は抑制された。このとき、それぞれの細胞層の構造変化を観察したところ、血管内皮細胞と周皮細胞に収縮性の変化が認められ、細胞間隙の形成が生じていた。一方、底面のアストログリアには著明な形態変化は認められなかった。以上の結果から、in vivoで観察されたHMGB1による脳血管の透過性亢進は、HMGB1が脳血管内皮細胞と周皮細胞に直接作用した結果であることが強く示唆された。脳梗塞とならび脳血管の透過性が亢進し脳浮腫を招来する病態として、脳外傷を挙げることができる。そこで、ラットにfluid percussionによる脳外傷を作成し、受傷局所におけるHMGB1局在の変化を調べた。Percussion injury局所の大脳皮質錐体神経細胞では、脳虚血部位で観察されたのと同様のHMGB1細胞内局在のトランスロケーションが観察された。つまり、正常脳部位では神経細胞核内に局在していたHMGB1が受傷部位では細胞質内に拡散している像や、細胞質内で顆粒状に集積している像が観察された。以上の結果から、脳外傷時には脳虚血と類似するHMGB1トランスロケーションの存在が明らかとなった。今後、動員されたHMGB1による脳血管透過性亢進について検討する必要がある。

RAGE ligandであるHMGB1は、壊死組織から、もしくはある種の刺激で単球・マクロファージからサイトカインのごとく分泌され、免疫応答に関与している。B細胞リンパ腫の濾胞はHMGB1を強発現していた。HMGB1は、ヒト悪性リンパ腫B細胞cell lineの増殖を誘導した。B細胞リンパ腫の発生原因は、単球・マクロファージによるB細胞の増殖と分化異常である。RAGE ligandである、HMGB1やAGEは単球を活性化した。故に、抗HMGB1抗体はB細胞リンパ腫の増殖を抑制すると考えた。

自然炎症という概念が提唱されてきた。これまでの自然免疫の延長線上に存在するものと、私共は考えている。私共は、受容体リガンドに注目して研究を進めている。

脳障害時のヌクレオカインHMGB1の脳内動態が詳細に検討された。つまり、正常脳細胞においては、殆どのHMGB1は神経細胞あるいはグリア細胞の核内、特に核小体に局在していること、一定時間の脳虚血によって大きく、4つのパターンの局在変化を示すことが明らかになった。一つ目は、核内においてほぼ均質に分布していたHMGB1が、レンコンの断面様に非存在部位を作って再分布する様式を示すタイプ、二つ目は、核膜部位に凝集塊を作る形で集積するタイプ、三つ目は、虚血の極く早期から細胞質内に顆粒状に分布移動するタイプ、四つ目は、均一な細胞質分布変化と細胞収縮を伴うタイプであった。これらの四つのタイプは、脳神経核の特定の部位に見られる傾向があった。上記の変化は中大脳動脈2時間閉塞後に再灌流し、その2時間後に得られた所見である。上記のHMGB1局在変化を生じた細胞の細胞外部位には小か顆粒状のHMGB1陽性構造共焦点レーザー顕微鏡による観察では多数見出され、細胞外放出像をとらえたものと考えられていた。Macintosh tissue chopperで作製されたラット海馬スライスを用いて、シェイファー側枝の高頻度刺激により、CA1領域にLTPを誘導した。この時に回収された灌流液中のHMGB1をElisaとウエスタンブロット法で測定を試みたが、両方とも検出感度以下のレベルであった。従って、LTP時にHMGB1の放出が顆亢進する実験的証拠は、今回の実験条件では、得られなかった。

虚血性心疾患と脳血管疾患は死因の上位を占める疾患群で、有効な治療法開発が待望されている。組換え型プラスミノーゲンアクチベータによる血栓溶解療法が梗塞の急性期治療法として導入されてきたが、治療有効時間帯の制限や、出血等の副作用のため有効性に限界があることも明らかになってきた。申請者は最近数年間、生体機能を調節する分子群のうち、特に単球/マクロファージの制御に関与する因子についての研究を進めてきた。単球/マクロファージの調節因子に注目した大きな理由は、このグループの分子群の中に各種疾患の炎症病態形成に関与する重要な因子が存在すると考えたからである。 申請者らは病巣指向性の抗ヌクレオカイン単クローン抗体による脳梗塞、心筋梗塞およびクモ膜下出血後脳血管攣縮の治療法開発を行ってきた。その結果、脳梗塞およびクモ膜下出血後脳血管攣縮に対してはこの中和抗体が著効し、壊死範囲が減少して後遺症が減少することがわかり、それぞれ特許第3876325号、3882090号という成果を得た。また、脳梗塞に対するに抗ヌクレオカイン単クローン抗体の治療効果ついてはFASEB Journalに『Anti-high mobility group box l monoclonal antibody ameliorates brain infarction induced by transient ischemia in rats.』として報告した。しかし、心筋梗塞モデルラットを用いた中和抗体の梗塞巣縮小効果の検討を行ったところ、左前下降枝下部の結紮による梗塞モデルにおいて、中和抗体は逆に心筋壊死範囲を増大した。この事は、治療薬として中和抗体の使用を考える上で、心機能障害者に対する使用の注意事項として確認できた。これらの一連の研究に対して、平成18年度武田科学振興財団報彰基金研究奨励と両備てい園記念財団研究助成を得ることができた。また、この研究に関連して、Mol Pharmacol.2006,70:450-453,FASEB J2007,21;3904-3916,Circulation J in pressなどの論文報告をした。

臨床的に敗血症と診断された下部消化管穿孔を中心とした患者に使用されたポリミキシンB固相化カラムを回収し、氷冷生食1500mlで洗浄後、カラムを開封しフィルターを取り出した。生食中でシェアストレスをかけることによってフィルター付着細胞を除去した後、フィルターに結合しているタンパク因子を飽和硫酸アンモニウム、グリシン-塩酸緩衝液(pH4.0)で連続して溶出した。溶出分画を回収後、バッファー交換し濃縮した。 回収された分画におけるヌクレオサイトカインを特異抗体を用いて検出したところ、飽和硫安による回収分画にヌクレオサイトカインが存在することが明らかにされた。カラムからは大量の白血球細胞が回収された。これらの白血球をFCS不含RPMI1640でインキュベートすることによってインキュベーション上清を得た。タンパク成分を硫安沈殿で回収し、透析後ヌクレオサイトカインの存在をウエスタンブロットで確認した。抗ヌクレオサイトカイン抗体をアガロースビーズに共有結合させ、このアフィニティ担体に上記のポリミキシンフィルターからの回収タンパク質ならびに白血球細胞のインキュベーション上清をアプライした。 標準品ヌクレオカインは、この抗体アフィニティカラムに結合したが、インキュベーション上清中のヌクレオカインは結合性を示さなかった。このことからヌクレオカインの翻訳後化学修飾、複合体形成、結合阻害物質の存在等の可能性が強く示唆させた。

炎症や組織再生の過程は,様々な生理活性因子群による極めて精巧な生命活動であり,その破綻は連鎖的な組織リモデリング(病的な組織構造や機能障害)に続く重篤な難治性疾患(動脈硬化や喘息など)を引き起こす。従って,これに寄与する因子群の同定と制御機構の解明は,病態の未然防止や治療法開発に通ずる最重要課題と言える。研究代表者らは,組織リモデリングに働く可能性を秘めた因子群がヒト血液中に存在する事を認め,血漿因子の一つである高ヒスチジン糖タンパク質(HRG)や細胞表面接着因子を介した細胞間相互作用が炎症や組織再生にとって重要な役割を担っている事を見出した。HRGについては高いヒスチジン含有量に着目した特異的精製法を既に開発しているので,これを用いて高純度のHRGを調製し,組織炎症時の重要な生体現象とされる血管新生系並びに好中球走化性に及ぼす役割について検討した。マトリゲルを用いたプラグアッセイを用いて血管新生に及ぼす影響を検討した所,bFGFとヘパリン混合液による血管新生反応に対してHRGが極めて強い阻害作用を発揮する事を見出した。この作用はHRGの血中濃度に相当する1μMで観察され,HRG分子中のヒスチジンリッチドメインが機能を担う事も明らかとなった。走化性については,HRGが好中球に対し有意な遊走活性を示す事が明らかとなった。一方,単球細胞などの免疫担当細胞の機能解析研究の中で,細胞間相互作用を担う細胞表面接着因子群の発現変化が,生体防御の観点から極めて重要な役割を果たしている事やサイトカインなどの様々な因子によって発現が影響を受ける事も明らかとなった。これらの知見からヒト血漿中には炎症や組織再生に働く極めて多彩な生理活性を示す因子群が存在し,複雑な制御の下でそれらの機能を発揮している事が明らかとなった。

申請者は、これまでインターロイキン18(IL-18)の種々の免疫応答調節機能について研究を行い、その作用機序として、免疫担当細胞の膜抗原蛋白である接着分子ICAM-1、B7、CD40を介する免疫細胞間相互作用の亢進が関与することを報告した。一方、炎症・免疫担当細胞で産生放出される内因性誘導型ヒスタミンの機能解析を行った結果、ヒスタミンは抗原提示細胞上の接着分子の発現抑制を介して免疫応答を制御することを見い出した(1)。このような、IL-18によって増幅される免疫炎症反応応答は、実験的肝炎モデルマウスにおいても認められ、さらに内因性誘導型ヒスタミンがH2受容体を介して肝炎を抑制することを報告した(2)。また、他のオータコイドのプロスタグランディン(PG)E1、PGE2、アドレナリンがヒスタミンの効果を模倣することを見い出した(3-8)。 1. J.Pharmacological.Sci.,92:7-12,2003.,review. 2. Gastroenterology,127:892-902,2004. 3. J.Pharmacol.Exp.Ther.,304:634-642,2003. 4. Transplantation,75:2100-2015,2003. 5. J.Pharmacol.Exp.Ther.,307:1188-1195,2003. 6. J.Neuroimmunol.,151:137-47,2004. 7. J.Pharmacol.Exp.Ther.,309:1213-1220,2004. 8. Transplantation,77:293-301,2004.

生体防御反応は、白血球を中心とする細胞間相互作用によって営まれ、それら細胞の活性化は液性因子ならびに接着分子を介して制御されている。液性因子としてすでに多くのサイトカイン、ケモカイン分子が同定されているものの、敗血症に代表されるSIRSあるいはCARS病態形成に関与するような血中因子の解析は殆ど進んでいない。このような背景に立って本研究では、以下の諸点について明らかにした。 1)現在我が国の敗血症治療には、血中LPSの除去を目的としてポリミキシンB結合カラム(PMX)への直接血液還流法が用いられている。本研究では、LPSの吸着除去に加え、液性タンパク因子の除去仮説の下に、網羅的、系統的な吸着タンパクプロファイリングとそれらの白血球細胞機能に対する効果の評価をおこなった。 2)群特異的リガンド(ポリミキシンB)でアフィニティ精製された血漿蛋白複合体プロテオミクスの解析により、S100A8,S100A12などのEFハンドカルシウム結合タンパクと、MIFならびにHMGB1を同定した。精製されたS100A12を用いてIL-18による刺激・非刺激時の単球/マクロファージ上のICAM-1、B7.1、B7.2、CD40、CD29、CD62L、CD31などの接着分子群の発現に対する効果を明らかにした。同様に、HMGB1の作用特性について解析した。 3)同定された因子の中で、HMGB1はエンドトキシン血症の致死応答に関与するメディエターと考えられている。組み換え体ヒトHMGB1タンパクを大腸菌に発現させることに成功した。大量精製法を目下検討しているが、この標品を得て敗血症における役割の研究に発展させる計画である。

近年、難治性疾患の原因として、HMGB1をはじめとしたRAGE ligandsが挙げられている。RAGE ligandとその受容体のRAGEとの結合に注目し、病態のメカニズムを検討し、抗体医薬や低分子化合物を開発する。