加藤 貴史 （カトウ タカシ）
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Last Updated :2024/04/23
研究活動情報
論文
- Takashi KatoJournal of Histochemistry & Cytochemistry 002215542210825 - 002215542210825 2022年02月PTEN is a well-known tumor suppressor with various functions that depend on its intracellular localization. Green fluorescent protein (GFP)-tagged live-cell images clarified the crucial amino acids needed to regulate the localization of PTEN in cells. However, it currently remains unknown whether GFP itself affects the intracellular localization of PTEN and its mutants, and the establishment of fixed-cell imaging is important for identifying the exact location of PTEN in cells. I herein investigated a number of immunofluorescence strategies for cell fixation, membrane permeabilization, and antigen retrieval. Permeabilization by detergents was necessary to observe nuclear and cytosolic PTEN in paraformaldehyde (PFA)-fixed cells; however, this permeabilization was not always valid. On the other hand, antigen retrieval by the pre-boiled EDTA treatment was useful for detecting plasma membranous PTEN in PFA-fixed cells in the same manner as in in vivo studies. Furthermore, methanol-fixed images of PTEN were consistent with GFP-tagged live-cell images. Two immunofluorescence methods (the PFA-fixed/pre-boiled EDTA treatment and methanol fixation) are applicable to investigations of the intracellular localization of PTEN without a GFP tag in cultured cells. In conclusion, live-cell imaging and appropriate immunofluorescence including a novel antigen retrieval treatment were both useful for detecting the cellular localization of PTEN, particularly at the plasma membrane.
- Takashi Kato; Atsushi Igarashi; Hiromi Sesaki; Miho IijimaGenes to cells : devoted to molecular & cellular mechanisms 26 12 1014 - 1022 2021年12月Many human diseases, including cancer and neurological abnormalities, are linked to deficiencies of phosphatase and tensin homolog deleted on chromosome ten (PTEN), a dual phosphatase that dephosphorylates both lipids and proteins. PTEN functions in multiple intracellular locations, including the plasma membrane and nucleus. Therefore, a critical challenge to understand the pathogenesis of PTEN-associated diseases is to determine the specific role of PTEN at different locations. Toward this goal, the current study generated a mouse line in which lysine 13, which is critical for the nuclear localization of PTEN, is changed to arginine in the lipid-binding domain using the CRISPR-Ca9 gene-editing system. We found that PTENK13R mice show a strong decrease in the localization of PTEN in the nucleus without affecting the protein stability, phosphatase activity, and phosphorylation in the C-terminal tail region. PTENK13R mice are viable but produce smaller neurons and develop microcephaly. These data demonstrate that PTENK13R mice provide a useful animal model to study the role of PTEN in the nucleus in vivo.
- Nuclear PTEN deficiency and heterozygous PTEN loss have distinct impacts on brain and lymph node sizeAtsushi Igarashi; Takashi Kato; Hiromi Sesaki; Miho IijimaBiochemical and Biophysical Research Communications 555 81 - 88 2021年05月 [査読有り]
- Nuclear PTEN and p53 suppress stress-induced liver cancer through distinct mechanismsTakashi Kato; Daisuke Murata Robert; A. Anders Hiromi; Sesaki Miho IijimaBiochemical and Biophysical Research Communications 549 83 - 90 2021年04月 [査読有り]
- Yoshihiro Adachi; Takashi Kato; Tatsuya Yamada; Daisuke Murata; Kenta Arai; Robert V Stahelin; David C Chan; Miho Iijima; Hiromi SesakiMolecular cell 80 4 621 - 632 2020年10月 [査読有り]
Mitochondria are highly dynamic organelles that continuously grow, divide, and fuse. The division of mitochondria is crucial for human health. During mitochondrial division, the mechano-guanosine triphosphatase (GTPase) dynamin-related protein (Drp1) severs mitochondria at endoplasmic reticulum (ER)-mitochondria contact sites, where peripheral ER tubules interact with mitochondria. Here, we report that Drp1 directly shapes peripheral ER tubules in human and mouse cells. This ER-shaping activity is independent of GTP hydrolysis and located in a highly conserved peptide of 18 amino acids (termed D-octadecapeptide), which is predicted to form an amphipathic α helix. Synthetic D-octadecapeptide tubulates liposomes in vitro and the ER in cells. ER tubules formed by Drp1 promote mitochondrial division by facilitating ER-mitochondria interactions. Thus, Drp1 functions as a two-in-one protein during mitochondrial division, with ER tubulation and mechano-GTPase activities. - Takashi Kato; Tatsuya Yamada; Hideki Nakamura; Atsushi Igarashi; Robert A Anders; Hiromi Sesaki; Miho IijimaiScience 23 10 101548 - 101548 2020年10月 [査読有り]
The PTEN gene is highly mutated in many cancers, including hepatocellular carcinoma. The PTEN protein is located at different subcellular regions-PTEN at the plasma membrane suppresses PI3-kinase signaling in cell growth, whereas PTEN in the nucleus maintains genome integrity. Here, using nuclear PTEN-deficient mice, we analyzed the role of PTEN in the nucleus in hepatocellular carcinoma that is induced by carcinogen and oxidative stress-producing hepatotoxin. Upon oxidative stress, PTEN was accumulated in the nucleus of the liver, and this accumulation promoted repair of DNA damage in wild-type mice. In contrast, nuclear PTEN-deficient mice had increased DNA damage and accelerated hepatocellular carcinoma formation. Both basal and oxidative stress-induced localization of PTEN in the nucleus require ubiquitination of lysine 13 in PTEN. Taken together, these data suggest the critical role of nuclear PTEN in the protection from DNA damage and tumorigenesis in vivo. - Kie Itoh; Daisuke Murata; Takashi Kato; Tatsuya Yamada; Yoichi Araki; Atsushi Saito; Yoshihiro Adachi; Atsushi Igarashi; Shuo Li; Mikhail Pletnikov; Richard L Huganir; Shigeki Watanabe; Atsushi Kamiya; Miho Iijima; Hiromi SesakieLife 8 2019年10月 [査読有り]
Dynamin-related protein 1 (Drp1) divides mitochondria as a mechano-chemical GTPase. However, the function of Drp1 beyond mitochondrial division is largely unknown. Multiple Drp1 isoforms are produced through mRNA splicing. One such isoform, Drp1ABCD, contains all four alternative exons and is specifically expressed in the brain. Here, we studied the function of Drp1ABCD in mouse neurons in both culture and animal systems using isoform-specific knockdown by shRNA and isoform-specific knockout by CRISPR/Cas9. We found that the expression of Drp1ABCD is induced during postnatal brain development. Drp1ABCD is enriched in dendritic spines and regulates postsynaptic clathrin-mediated endocytosis by positioning the endocytic zone at the postsynaptic density, independently of mitochondrial division. Drp1ABCD loss promotes the formation of ectopic dendrites in neurons and enhanced sensorimotor gating behavior in mice. These data reveal that Drp1ABCD controls postsynaptic endocytosis, neuronal morphology and brain function. - Man Hagiyama; Yoshihisa Nakatani; Yasutoshi Takashima; Takashi Kato; Takao Inoue; Ryuichiro Kimura; Tomoyuki Otani; Yasufumi Sato; Hideo Mori; Shuji Arima; Akihiko ItoFrontiers in cell and developmental biology 7 111 - 111 2019年 [査読有り]
Cell adhesion molecule 1 (CADM1) is an immunoglobulin superfamily member strongly expressed on renal tubular epithelia in the urinary tract. Enzymatic cleavage of its ectodomain increases in chronic kidney disease (CKD), and is assumed to contribute to tubulointerstitial lesion formation. Because the cleaved ectodomain fragments are likely to be released into the urine, a sandwich enzyme-linked immunosorbent assay (ELISA) system for urinary CADM1 was developed using two anti-ectodomain antibodies. Urinary CADM1 concentrations in patients with CKD based on various forms of glomerulonephritis and nephropathy (n = 127) were measured. A total of 44 patients (35%) had elevated CADM1 concentrations over the normal upper limit (362 pg/mL), with a mean of 1,727 pg/mL. Renal biopsy specimens of all patients were pathologically scored for tubulointerstitial lesions using epithelial degeneration, interstitial inflammation, and fibrosis. There were no correlations between urinary CADM1 concentrations and pathological scores or any widely used renal markers, including glomerular filtration rate (GFR), but there was a weak inverse correlation between pathological scores and GFR (R2 = 0.292). Notably, this correlation gradually increased in patients with increasing CADM1 concentrations, and reached a maximum R2 (0.899) at a cutoff of 1,569 pg/mL. The results of this study suggest that urinary CADM1 is a useful marker indicating tubulointerstitial damage from elevated GFR levels in CKD. - Tatsuya Yamada; Daisuke Murata; Yoshihiro Adachi; Kie Itoh; Shoichiro Kameoka; Atsushi Igarashi; Takashi Kato; Yoichi Araki; Richard L Huganir; Ted M Dawson; Toru Yanagawa; Koji Okamoto; Miho Iijima; Hiromi SesakiCell metabolism 28 4 588 - 604 2018年10月 [査読有り]
It is unknown what occurs if both mitochondrial division and fusion are completely blocked. Here, we introduced mitochondrial stasis by deleting two dynamin-related GTPases for division (Drp1) and fusion (Opa1) in livers. Mitochondrial stasis rescues liver damage and hypotrophy caused by the single knockout (KO). At the cellular level, mitochondrial stasis re-establishes mitochondrial size and rescues mitophagy defects caused by division deficiency. Using Drp1KO livers, we found that the autophagy adaptor protein p62/sequestosome-1-which is thought to function downstream of ubiquitination-promotes mitochondrial ubiquitination. p62 recruits two subunits of a cullin-RING ubiquitin E3 ligase complex, Keap1 and Rbx1, to mitochondria. Resembling Drp1KO, diet-induced nonalcoholic fatty livers enlarge mitochondria and accumulate mitophagy intermediates. Resembling Drp1Opa1KO, Opa1KO rescues liver damage in this disease model. Our data provide a new concept that mitochondrial stasis leads the spatial dimension of mitochondria to a stationary equilibrium and a new mechanism for mitochondrial ubiquitination in mitophagy. - Atsushi Igarashi; Kie Itoh; Tatsuya Yamada; Yoshihiro Adachi; Takashi Kato; Daisuke Murata; Hiromi Sesaki; Miho IijimaThe Journal of biological chemistry 293 24 9292 - 9300 2018年06月 [査読有り]
Defects in phosphatase and tensin homolog (PTEN) are associated with neurological disorders and tumors. PTEN functions at two primary intracellular locations: the plasma membrane and the nucleus. At the membrane, PTEN functions as a phosphatidylinositol (3,4,5)-trisphosphate phosphatase and suppresses PI 3-kinase signaling that drives cell growth and tumorigenesis. However, the in vivo function of nuclear PTEN is unclear. Here, using CRISPR/Cas9, we generated a mouse model in which PTEN levels in the nucleus are decreased. Nuclear PTEN-deficient mice were born with microcephaly and maintained a small brain during adulthood. The size of neuronal soma was significantly smaller in the cerebellum, cerebral cortex, and hippocampus. Also, these mice were prone to seizure. No changes in PI 3-kinase signaling were observed. By contrast, the size of other organs was unaffected. Therefore, nuclear PTEN is essential for the health of the brain by promoting the growth of neuronal soma size during development. - Takashi Kato; Man Hagiyama; Yasutoshi Takashima; Azusa Yoneshige; Akihiko ItoAmerican journal of physiology. Renal physiology 314 3 F388-F398 2018年03月 [査読有り]
Chronic kidney disease (CKD) is an important problem throughout the world, associated with the increase of blood urea nitrogen (BUN) and serum creatinine (sCre) and with renal tubular injuries. It is crucial to elucidate the molecular mechanisms of renal injuries to identify the new therapeutics and early diagnostic methods. We focused on cell adhesion molecule-1 (CADM1) protein. CADM1, its isoform SP4, is expressed in the epithelial cells of various tissues, including renal distal tubules, localized on the lateral cell membrane, mediates cell-cell adhesion via trans-homophilic binding, and interacts with various proteins. We previously reported that its expression was downregulated by post-proteolytic cleavage (α- and β-shedding) in pulmonary diseases. To investigate whether CADM1 α-shedding occurs in human nephropathies, we performed Western blotting and immunohistochemical analysis of specimens with arterionephrosclerosis (AS) and diabetic nephropathy (DN) from autopsied kidneys. CADM1 α-shedding was induced in AS and DN kidneys and derived from the decrease in full-length CADM1 (FL-CADM1) and increase of the COOH-terminal fragment (α-CTF). In particular, the reduced FL-CADM1 level was correlated with tubular and tubulointerstitial injuries and the increases in BUN and sCre levels. Apoptosis of renal tubular epithelial cells (TECs) was promoted in both nephropathies, and it was significantly correlated with the decrease in the FL-CADM1. Furthermore, FL-CADM1 knockdown by small interfering RNA downregulated anti-apoptotic Bcl-2 protein and promoted apoptosis of cultured renal TECs. The present study suggests that the reduction of FL-CADM1 leads to renal TEC apoptosis and could exacerbate renal tubular and tubulointerstitial injuries, which contribute to the development of CKD. - Takashi Kato; Kiyomasa Oka; Toshikazu NakamuraMolecular medicine reports 17 1 1031 - 1034 2018年01月 [査読有り]
Extracellular potassium homeostasis is dependent on the activity of potassium channels, which are expressed on the apical membrane of epithelial tubular cells. The renal outer medullary potassium channel (ROMK) is considered to be the major route for potassium transport into the tubule lumen. Hepatocyte growth factor (HGF) exerts multiple biological activities and is important for maintaining renal homeostasis. It is also anti‑apoptotic and mitogenic for protection and recovery from ARF. Whether HGF regulates the ion channel activities remains to be elucidated, therefore, the present study aimed to investigate the modulation of HGF on the expression of ROMK in cultured renal tubular cells. NRK‑52E cells were treated with recombinant HGF, however, no alterations in the total expression of ROMK were observed by western blot analysis. In examining the serine 44 phosphorylation of ROMK in NRK‑52E cells, the present study observed that HGF enhanced the serine 44 phosphorylation of ROMK. In addition, to investigate whether HGF‑Met signaling induces the movement of ROMK to the cell surface in NRK‑52E cells, the protein constituents of cells were separated into plasma membrane and cytoplasm. Using immunofluorescence assay, the expression of ROMK on the plasma membrane was increased in the HGF‑treated NRK‑52E cells, which suggested that ROMK was translocated to the plasma membrane following the HGF‑induced phosphorylation of serine 44. Therefore, HGF may be important in potassium excretion and perform antihyperkalemic effects through the translocation of potassium channels. - Takashi Kato; Shinya MizunoExperimental animals 66 3 183 - 189 2017年08月 [査読有り]
Newborn mouse glomeruli are still immature with a morphological feature of an early capillary loop stage, but infant mice do not manifest proteinuria. Little is known about the molecular mechanism whereby infant mice are resistant to proteinuria. Nephrin and synaptopodin are crucial for slit diaphragm and foot process (FP) formation for avoiding proteinuria. Nephrin tyrosine phosphorylation means a transient biological signaling required for FP repair or extension during nephrotic disease. Using an immunohistochemical technique, we examined the natural course of nephrin, Wilms' tumor-1 (WT1) and synaptopodin at 16.5 days of embryonic age (E16.5d) and E19.5d, 7 days of post-neonatal age (P7d) and P42d during renal development of mice. As a result, nephrin and synaptopodin were detected at E19.5d in S-shaped bodies. WT1, a transcriptional factor for nephrin, was detected in nucleus in podocyte-like cells in all stages. Nephrin tyrosine phosphorylation was evident in glomeruli at P7d, and this was associated with an early-stage of FP extension. Inversely, nephrin phosphorylation became faint at P42d, along with maturated FP. Based on the present results, we suggest the sequential molecular mechanism to protect growing mice from proteinuria: (i) WT1-induced nephrin production by podocytes in S-shaped bodies at E19.5d; (ii) Synchronized induction of synaptopodin at the same period; and (iii) FP extension is initiated at a milk-suckling stage under a nephrin tyrosine-phosphorylated condition, while it is arrested at an adult stage, associated with a loss of nephrin-based signaling. - Takashi Kato; Nobuyuki Mizuguchi; Akihiko ItoJournal of Biomedicine 2 57 - 63 2017年 [査読有り]
- Takashi Kato; Kiyomasa Oka; Toshikazu Nakamura; Akihiko ItoEuropean Journal of Histochemistry 60 1 2575 2016年02月 [査読有り]
<p>Organ-specific stem cells play key roles in maintaining the epithelial cell layers of lung. Bronchioalveolar stem cells (BASCs) are distal lung epithelial stem cells of adult mice. Alveolar type 2 (AT2) cells have important functions and serve as progenitor cells of alveolar type 1 (AT1) cells to repair the epithelium when they are injured. Hepatocyte growth factor (HGF) elicits mitogenic, morphogenic, and anti-apoptotic effects on lung epithelial cells through tyrosine phosphorylation of Met receptor, and thus is recognized as a pulmotrophic factor. To understand which cells HGF targets in lung, we identified the cells expressing Met by immunofluorescence assay. Met was strongly expressed in BASCs, which expressed an AT2 cell marker, pro-SP-C, and a club cell marker, CCSP. In alveoli, we found higher expression of Met in primary AT2 than in AT1 cells, which was confirmed using primary AT2 cells. We further examined the mitogenic activity of HGF in AT2-cell-derived alveolar-like cysts (ALCs) in 3D culture. Multicellular ALCs expressed Met, and HGF enhanced the ALC production. Taking these findings together, BASCs could also be an important target for HGF, and HGF-Met signaling could function more potent on cells that have greater multipotency in adult lung.</p> - Takashi Kato; Kiyomasa Oka; Toshikazu Nakamura; Akihiko ItoJournal of cellular and molecular medicine 19 12 2818 - 26 2015年12月 [査読有り]
Lung alveolar regeneration occurs in adult human lungs as a result of proliferation, differentiation and alveolar morphogenesis of stem cells. It is increasingly being believed that bronchial epithelial cells (BECs) have a potential as stem cells, because they are potent to differentiate into multiple central and peripheral lung cell types in three-dimensional (3D) cultures, and they develop multiple foci with well-differentiated histogenesis after transformed into neoplastic cells. In this study, we investigated morphogenic abilities of HBE135 human BECs immortalized by E6/E7 oncogene in 3D cultures. When HBE135 cells were cultured alone or co-cultured with endothelial cells, the cells formed spherical colonies without branching. However, in co-culture with lung fibroblast MRC-9 cells, HBE135 cells formed colonies with bronchioalveolar-like complex branching, suggesting that MRC-9-derived soluble factor(s) are responsible for the branching formation. MRC-9 cells, not endothelial cells, were found to highly express hepatocyte growth factor (HGF), a soluble molecule involved in liver and kidney regeneration. An anti-HGF neutralizing antibody severely suppressed the complex branching formation, but addition of HGF could not sufficiently compensate the morphogenic effects of MRC-9 cells, suggesting that MCR-9-derived HGF was necessary but insufficient for the bronchioalveolar structure formation. Immunohistochemistry revealed that Met, a cognate receptor for HGF, was highly expressed and phosphorylated in neoplastic BECs from lung adenocarcinomas with well-differentiated, not poorly differentiated, histogenesis. These results are consistent with the notion that BECs have an aspect of stem cells. This aspect appears to become manifest through HGF-Met signalling pathway activation. - Takashi Kato; Nobuyuki Mizuguchi; Akihiko ItoBiomedical research (Tokyo, Japan) 36 5 313 - 21 2015年10月 [査読有り]
Proteinuria is not only a hallmark of renal complication in malignant hypertension, but is also a major deteriorating factor for the progression to end-stage renal disease. Podocyte injury plays a crucial role in the renal damage associated with hypertensive nephropathy, but the underlying mechanism remains unclear. Malignant stroke-prone spontaneously hypertensive rats (MSHRSP/Kpo) represent an original and useful model of human malignant hypertension. In this study, we disclosed the glomerular injuries in the MSHRSP/Kpo. MSHRSP/Kpo exhibited elevated blood pressure at 6 weeks along with renal dysfunction and proteinuria. Histological analysis of the MSHRSP/Kpo glomeruli revealed a severe atrophy, but no change was found in the podocyte number. The expression levels of podocyte-specific proteins, nephrin, podocin, and synaptopodin were decreased in the MSHRSP/Kpo glomeruli, though another podocyte-specific protein, CD2AP, in the MSHRSP/Kpo glomeruli exhibited a similar extent of staining as in normotensive WKY/Kpo rats. Furthermore, desmin was not markedly detected in the WKY/Kpo glomeruli, but was strongly positive in MSHRSP/Kpo. By electron microscopy, well-formed foot processes (FP) were replaced by effacement in MSHRSP/Kpo. An original malignant hypertension strain MSHRSP/Kpo exhibits podocyte injuries associated with the decrease of some podocyte-specific proteins and the upregulation of desmin, along with FP effacement and proteinuria. - Azusa Yoneshige; Man Hagiyama; Takao Inoue; Takahiro Mimae; Takashi Kato; Morihito Okada; Eisuke Enoki; Akihiko ItoRespiratory research 16 90 - 90 2015年08月 [査読有り]
BACKGROUND: Lung alveolar epithelial cell (AEC) apoptosis has attracted attention as an early pathogenic event in the development of idiopathic interstitial pneumonia (IIP); however, the causative mechanism remains unclear. Cell adhesion molecule 1 (CADM1) is an AEC adhesion molecule in the immunoglobulin superfamily. It generates a membrane-associated C-terminal fragment, αCTF, through protease-mediated ectodomain shedding, termed α-shedding. Increased CADM1 α-shedding contributes to AEC apoptosis in emphysematous lungs. METHODS: Formalin-fixed, paraffin-embedded lung lobes (n = 39) from 36 autopsied patients with IIP were classified as acute IIP (n = 10), fibrosing-type nonspecific IIP (f-NSIP, n = 10), cryptogenic organizing IIP (n = 9), and usual IIP (n = 10). CADM1 expression in the lung sections was examined by western blotting and compared with control lungs (n = 10). The rate of CADM1 α-shedding was calculated as the relative amount of αCTF to full-length CADM1, and the full-length CADM1 level was estimated per epithelial cell by normalization to cytokeratin 7, a lung epithelial marker. Apoptotic AECs were detected by immunohistochemistry for single-stranded DNA (ssDNA). NCI-H441 and A549 human lung epithelial cells were transfected with small interfering RNA (siRNA) to silence CADM1 expression and analyzed by terminal nucleotide nick end labeling assays. RESULTS: The rate of CADM1 α-shedding was higher in all IIP subtypes than in the control (P ≤ 0.019), and the full-length CADM1 level was lower in f-NSIP (P = 0.007). The α-shedding rate and full-length CADM1 level were correlated with each other (P = 0.015) and with the proportion of ssDNA-positive AECs (P ≤ 0.024). NCI-H441 cells transfected with siRNA exhibited a 61 % lower rate of expression of full-length CADM1 and a 17-fold increased proportion of apoptotic cells. Similar results were obtained with A549 cells. CONCLUSIONS: CADM1 α-shedding appeared to be increased in all four IIP subtypes and consequently contributed to AEC apoptosis by decreasing the full-length CADM1 level. This mechanism particularly impacted f-NSIP. The molecular mechanism causing AEC apoptosis may be similar between IIP and emphysema. - Takashi Kato; Nobuyuki Mizuguchi; Akihiko ItoBiomedical research (Tokyo, Japan) 36 3 169 - 77 2015年06月 [査読有り]
Hypertensive nephropathy, a consequence of chronic high blood pressure, is increasingly a cause of end-stage renal diseases and its correct management is very important for clinical outcome. Spontaneously hypertensive rat (SHR/Kpo) and stroke-prone SHR (SHRSP/Kpo) strains represent models of human essential hypertension. However, the kidney injuries in SHR/Kpo and SHRSP/Kpo are not well defined. We therefore characterized the renal pathophysiology of SHR/Kpo and SHRSP/Kpo compared with normotensive control (WKY/Kpo) rats. The SHRSP/Kpo exhibited increased systolic blood pressure at 10 weeks of age, and proteinuria and increased blood urea nitrogen (BUN) and serum creatinine levels at 20 weeks. We simultaneously detected mononuclear cell infiltration, tubular injuries, accumulation of extracellular matrix and marked expression of α-SMA in the tubulointerstitium. Additionally, TGF-β1 and CTGF were up-regulated in the kidney of SHRSP/Kpo. We lastly focused on changes in glomerular cells of SHRSP/Kpo. Nestin, a podocyte marker, was detected but decreased slightly in 20-week-old SHRSP/Kpo. PECAM-1 expression was increased in SHRSP/Kpo glomeruli, indicating the thickening of glomerular endothelial cells. Moreover, we found that α-SMA, a myofibroblast marker, was also upregulated in the glomeruli of SHRSP/Kpo at 20 weeks. These findings suggest that SHRSP/Kpo could be a valuable animal model for human hypertensive nephropathy. - Takashi Kato; Toshikazu Nakamura; Kiyomasa Oka; Ryoichi SakiyamaJournal of Pharmacology and Pharmacotherapeutics 6 2 77 - 82 2015年04月 [査読有り]
- Hiroyuki Ohnishi; Shinya Mizuno; Yoko Mizuno-Horikawa; Takashi KatoThe Journal of veterinary medical science 77 3 313 - 9 2015年03月 [査読有り]
Ischemic acute kidney injury (AKI) is the most key pathological event for accelerating progression to chronic kidney disease through vascular endothelial injury or dysfunction. Thus, it is critical to elucidate the molecular mechanism of endothelial protection and regeneration. Emerging evidence indicates that bone marrow-derived cells (BMCs) contribute to tissue reconstitution in several types of organs post-injury, but little is known whether and how BMCs contribute to renal endothelial reconstitution, especially in an early-stage of AKI. Using a mouse model of ischemic AKI, we provide evidence that incorporation of BMCs in vascular components (such as endothelial and smooth muscle cells) becomes evident within four days after renal ischemia and reperfusion, associated with an increase in stromal cell-derived factor-1 (SDF1) in endothelium and that in CXCR4/SDF1-receptor in BMCs. Notably, anti-CXCR4 antibody decreased the numbers of infiltrated BMCs and BMC-derived endothelium-like cells, but not of BMC-derived smooth muscle cell-like cells. These results suggest that reconstitution of renal endothelium post-ischemia partially depends on a paracrine loop of SDF1-CXCR4 between resident endothelium and BMCs. Such a chemokine ligand-receptor system may be attributable for selecting a cellular lineage (s), required for renal vascular protection, repair and homeostasis, even in an earlier phase of AKI. - Takashi Kato; Shinya Mizuno; Akihiko ItoActa histochemica et cytochemica 47 6 265 - 71 2014年12月 [査読有り]
The ICR-derived glomerulonephritis (ICGN) mouse is a unique model of nephrotic syndrome, and albuminuria becomes evident in a neonatal stage, due to a genetic mutation of tensin2. We previously provided evidence that an apparent decrease in nephrin, caused by tensin2-deficiencient states, leads to podocytopathy, albuminuria and eventually, chronic renal failure. In general, glomerular endothelial cells (ECs) function as a barrier through tight attachment of glomerular basement membrane to podocytes, while decreased ECs can worsen renal failure. Nevertheless, it is still unknown whether glomerular ECs are altered under the tensin-2-deficient states during the manifestation of chronic renal failure. Herein, we examined the changes of glomerular ECs, with focus on the expression of PECAM-1 and VE-cadherin (EC-specific markers), or of α-SMA (myofibroblast marker) in this mouse model by histological methods. Compared with the non-nephrotic (+/nep) mice, the nephrotic (nep/nep) mice exhibited the reduced expression of PECAM-1, or of VE-cadherin, in glomerular area. Notably, some glomerular ECs showed the positive stainings for both PECAM-1 and α-SMA, suggesting endothelial-to-mesenchymal transition (EndoMT) during progression of glomerular sclerosis. This is the first report showing that a decrease in glomerular ECs, at least in part, via EndoMT is involved in tensin2-deficient pathological conditions. - バーチャルスライドを併用した病理学実習における学生意識筑後 孝章; 米重 あづさ; 加藤 貴史; 萩山 満; 井上 敬夫; 榎木 英介; 伊藤 龍生; 前西 修; 木村 雅友; 佐藤 隆夫; 伊藤 彰彦医学教育 45 Suppl. 183 - 183 (一社)日本医学教育学会 2014年07月
- Takao Inoue; Man Hagiyama; Azusa Yoneshige; Takashi Kato; Eisuke Enoki; Osamu Maenishi; Takaaki Chikugo; Masatomo Kimura; Takao Satou; Akihiko ItoPloS one 9 6 e100988 2014年06月 [査読有り]
Pulmonary emphysema and type 2 diabetes mellitus (T2DM), both caused by lifestyle factors, frequently concur. Respectively, the diseases affect lung alveolar and pancreatic islet cells, which express cell adhesion molecule 1 (CADM1), an immunoglobulin superfamily member. Protease-mediated ectodomain shedding of full-length CADM1 produces C-terminal fragments (CTFs) with proapoptotic activity. In emphysematous lungs, the CADM1 shedding rate and thus the level of CTFs in alveolar cells increase. In this study, CADM1 expression in islet cells was examined by western blotting. Protein was extracted from formalin-fixed, paraffin-embedded sections of pancreata isolated from patients with T2DM (n = 12) or from patients without pancreatic disease (n = 8) at autopsy. After adjusting for the number of islet cells present in the adjacent section, we found that full-length CADM1 decreased in T2DM islets, while ectodomain shedding increased. Hemoglobin A1c levels, measured when patients were alive, correlated inversely with full-length CADM1 levels (P = 0.041) and positively with ectodomain shedding rates (P = 0.001). In immunofluorescence images of T2DM islet cells, CADM1 was detected in the cytoplasm, but not on the cell membrane. Consistently, when MIN6-m9 mouse beta cells were treated with phorbol ester and trypsin to induce shedding, CADM1 immunostaining was diffuse in the cytoplasm. When a form of CTFs was exogenously expressed in MIN6-m9 cells, it localized diffusely in the cytoplasm and increased the number of apoptotic cells. These results suggest that increased CADM1 ectodomain shedding contributes to blood glucose dysregulation in T2DM by decreasing full-length CADM1 and producing CTFs that accumulate in the cytoplasm and promote apoptosis of beta cells. Thus, this study has identified a molecular alteration shared by pulmonary emphysema and T2DM. - Takahiro Mimae; Man Hagiyama; Takao Inoue; Azusa Yoneshige; Takashi Kato; Morihito Okada; Yoshinori Murakami; Akihiko ItoThorax 69 3 223 - 31 2014年03月 [査読有り]
RATIONALE: Alveolar epithelial cell apoptosis and protease/antiprotease imbalance based proteolysis play central roles in the pathogenesis of pulmonary emphysema but molecular mechanisms underlying these two events are not yet clearly understood. Cell adhesion molecule 1 (CADM1) is a lung epithelial cell adhesion molecule in the immunoglobulin superfamily. It generates two membrane associated C terminal fragments (CTFs), αCTF and βCTF, through protease mediated ectodomain shedding. OBJECTIVE: To explore the hypothesis that more CADM1-CTFs are generated in emphysematous lungs through enhanced ectodomain shedding, and cause increased apoptosis of alveolar epithelial cells. METHODS AND RESULTS: Western blot analyses revealed that CADM1-CTFs increased in human emphysematous lungs in association with increased ectodomain shedding. Increased apoptosis of alveolar epithelial cells in emphysematous lungs was confirmed by terminal nucleotide nick end labelling (TUNEL) assays. NCI-H441 lung epithelial cells expressing mature CADM1 but not CTFs were induced to express αCTF both endogenously (by shedding inducers phorbol ester and trypsin) and exogenously (by transfection). Cell fractionation, immunofluorescence, mitochondrial membrane potentiometric JC-1 dye labelling and TUNEL assays revealed that CADM1-αCTF was localised to mitochondria where it decreased mitochondrial membrane potential and increased cell apoptosis. A mutation in the intracytoplasmic domain abrogated all three abilities of αCTF. CONCLUSIONS: CADM1 ectodomain shedding appeared to cause alveolar cell apoptosis in emphysematous lungs by producing αCTF that accumulated in mitochondria. These data link proteolysis to apoptosis, which are two landmark events in emphysema. - Masaoki Ito; Man Hagiyama; Takahiro Mimae; Takao Inoue; Takashi Kato; Azusa Yoneshige; Jun Nakanishi; Tadashi Kondo; Morihito Okada; Akihiko ItoBreast cancer research and treatment 144 1 59 - 69 2014年02月 [査読有り]
Invasive lobular carcinoma (ILC) is more frequently lymph node positive than is invasive ductal carcinoma (IDC), and ILC cell infiltration shows distinctive histological characteristics, suggesting the action of ILC-specific invasion molecules. To identify such a molecule, we used a proteomic approach in the pseudopodia of MDA-MB-231 breast cancer cells. A pseudopodial constituent was identified using excimer laser ablation, two-dimensional difference gel electrophoresis, mass spectroscopy, and immunocytofluorescence. MDA-MB-231 cells were modified to express various levels of this constituent by transient transfection and were examined for pseudopodia formation and migratory abilities using wound healing and two-chamber assays. Immunohistochemical positivity of human breast cancer cells (56 ILCs and 21 IDCs) was compared with clinicopathological variables. An actin-binding adaptor protein, α-parvin, was found to localize to pseudopodia and to form focal adhesions in cells not induced to extend pseudopodia. Pseudopodial length and density and migratory abilities correlated with α-parvin expression. Twenty-one (37.5 %) ILCs stained positive for α-parvin, whereas the results were negative for all 21 IDCs (P < 0.001). α-Parvin positivity in ILC was significantly associated with lymphatic invasion (P = 0.038) and lymph node metastasis (P = 0.003) in univariate analyses and to lymph node metastasis (P = 0.020) in multivariate analyses. α-Parvin, a pseudopodial constituent, was found to promote migration of breast cancer cells and to be expressed exclusively by ILC, suggesting that α-parvin is an ILC-specific invasion molecule that may have clinical utility as a biomarker for aggressive subsets of ILC. - Takashi Kato; Hiroshi Funakoshi; Keiichi Kadoyama; Satsuki Noma; Masaaki Kanai; Wakana Ohya-Shimada; Shinya Mizuno; Nobutaka Doe; Taizo Taniguchi; Toshikazu NakamuraJournal of neuroscience research 90 9 1743 - 55 2012年09月 [査読有り]
Hepatocyte growth factor (HGF) and its receptor, c-Met, play pivotal roles in the nervous system during development and in disease states. However, the physiological roles of HGF in the adult brain are not well understood. In the present study, to assess its role in learning and memory function, we used transgenic mice that overexpress HGF in a neuron-specific manner (HGF-Tg) to deliver HGF into the brain without injury. HGF-Tg mice displayed increased alternation rates in the Y-maze test compared with age-matched wild-type (WT) controls. In the Morris water maze (MWM) test, HGF-Tg mice took less time to find the platform on the first day, whereas the latency to escape to the hidden platform was decreased over training days compared with WT mice. A transfer test revealed that the incidence of arrival at the exact location of the platform was higher for HGF-Tg mice compared with WT mice. These results demonstrate that overexpression of HGF leads to an enhancement of both short- and long-term memory. Western blot analyses revealed that the levels of N-methyl-D-aspartate (NMDA) receptor subunits NR2A and NR2B, but not NR1, were increased in the hippocampus of HGF-Tg mice compared with WT controls, suggesting that an upregulation of NR2A and NR2B could represent one mechanism by which HGF enhances learning and memory performance. These results demonstrate that modulation of learning and memory performance is an important physiological function of HGF that contributes to normal CNS plasticity, and we propose HGF as a novel regulator of higher brain functions. - Takashi Kato; Yoko Mizuno-Horikawa; Shinya MizunoThe Journal of veterinary medical science 73 12 1579 - 84 2011年12月 [査読有り]
Podocytes have a peculiar structure constituting slit diaphragm (SD) and foot process (FP), and play essential roles in the glomerular filtration barrier. There is now ample evidence that SD- and FP-associated molecules, such as podocin and CD2-associated protein (CD2AP), are down-regulated during albuminuria of chronic kidney disease. However, it is still unclear whether these molecules are altered during acute renal failure (ARF) with albuminuria. Using lipopolysaccharide (LPS)-treated mice as a model of septic ARF, we provide evidence that the expression of SD- and FP-associated molecules becomes faint, along with albuminuria. In the LPS-treated mice, urinary albumin levels gradually increased, associated with the elevation of blood urea nitrogen levels, indicating the successful induction of albuminuria during septic ARF. In this pathological process, glomerular podocin expression became faint, especially at 36 hr post-LPS challenge (i.e., a peak of albuminuria). Likewise, LPS treatment led to a significant decrease in CD2AP, an anchorage between podocin and F-actin. With regard to this, tensin2 is a novel molecule that stabilizes F-actin extension. Interestingly, glomerular tensin2 expression levels were also decreased during the albuminuric phase, associated with losses of glomerular F-actin and synaptopodin under septic states. As a result, there were some lesions of podocytic FP effacement, as shown by electron microscopy. Based on these data, we emphasize the importance of concomitant decreases in podocin, CD2AP and tensin2 during septic ARF-associated proteinuria. - Shinya Mizuno; Fumie Ikebuchi; Kazuhiro Fukuta; Takashi Kato; Kunio Matsumoto; Kiichi Adachi; Tetsushi Abe; Toshikazu NakamuraClinical and experimental pharmacology & physiology 38 3 192 - 201 2011年03月 [査読有り]
1. Hepatocyte growth factor (HGF) has the therapeutic potential to improve renal fibrosis and proteinuria in rodents with chronic kidney disease. In contrast, long-term administration of human HGF to normal rats reportedly elicits proteinuria. Thus, the role of HGF during proteinuria remains contentious. The aim of the present study was to demonstrate that human HGF is antigenic to rodents and that immune complex formation causes proteinuria. 2. We administered either human or rat HGF to normal rats for 28 days. Albuminuria was evaluated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The renal phenotypes of the two HGF treatments were examined using histological techniques. 3. Administration of human HGF (1 mg/kg per day, i.v.) to rats led to severe albuminuria and glomerular hypertrophy in association with increased blood levels of anti-human HGF IgG and IgG deposition in mesangial areas. Furthermore, an immune complex between human HGF and anti-human HGF IgG stimulated the production of proteinuric cytokines (including transforming growth factor-β) in rat cultured mesangial cells. In contrast, treatment of healthy rats with rat HGF for 4 weeks caused neither mesangial IgG deposition nor elevated anti-HGF IgG in the blood. Overall, rat HGF did not provoke albuminuria. 4. We conclude that human HGF produces pseudotoxic effects in normal rat kidneys via an immune complex-mediated pathway, whereas syngenic HGF is safe due to less deposition of glomerular IgG. Our results affirm the safety of the repeated use of syngenic HGF for the treatment of chronic organ diseases, such as renal fibrosis and liver cirrhosis. - Takashi Kato; Shinya Mizuno; Toshikazu NakamuraNephrology (Carlton, Vic.) 16 3 310 - 8 2011年03月 [査読有り]
AIM: Podocytes provide a slit diaphragm to inhibit proteinuria, and nephrin between podocytes functions as a barrier during glomerular filtration. Hepatocyte growth factor (HGF) can improve proteinuria in rodents with various renal injuries, but little is known about the role of HGF in podocyte-based events during glomerulonephritis. In the present study, we examined whether and how nephrin expression is sustained by podocytes during the HGF-mediated attenuation of albuminuria. METHODS: Lipopolysaccharide (LPS)-treated mice were used as an animal model of albuminuria. We evaluated the effect of HGF on slit proteins using immunohistochemistry, western blotting and real-time polymerase chain reaction. RESULTS: Albuminuria occurred 36 h after LPS treatment in mice. This albuminuria did not involve podocyte loss, but was associated with a decrease in nephrin and its key anchor, synaptopodin. In these processes, c-Met tyrosine phosphorylation, which represented HGF signal activation, occurred in glomerular cells including podocytes. When recombinant HGF was administrated to nephritic mice, c-Met tyrosine phosphorylation became evident in podocytes. The enhancement of the HGF-c-Met signal was associated with increases in nephrin and synaptopodin. An electron microscopic examination revealed that LPS induced the foot process effacement of podocytes, while HGF injections suppressed the foot process injury. Overall, albuminuria was attenuated in the LPS-treated mice after HGF administration. CONCLUSION: HGF protects podocytes from a loss of nephrin, at least in part, through maintaining synaptopodin. As a result, HGF was shown to sustain foot process structure, and albuminuria was attenuated under inflammation. - Takashi Kato; Shinya Mizuno; Miyuki KamimotoBiomedical research (Tokyo, Japan) 31 6 363 - 9 2010年12月 [査読有り]
Sepsis is induced by infectious challenges, and septic organ failure often occurs under local and systemic inflammation. Albuminuria is also evident during sepsis, but little is known about the molecular basis of septic albuminuria. Using lipopolysaccharide (LPS)-treated mice as a sepsis model, we found that the loss of nephrin, a key component for maintaining podocyte slit diaphragm, became evident in accordance with the onset of albuminuria, especially 36 h post-LPS challenge (i.e., albumiuric stage). Likewise, nephrin mRNA levels were decreased to 13% of saline-treated mice. Such a transcriptional suppression of nephrin was associated with the loss of nucleus-localized Wilms tumor-1 (WT1), a transcriptional factor for up-regulating nephrin gene. Thereafter, urinary albumin levels were decreased in mice between 72 and 96 h post-LPS challenge (i.e., recovery-stage). Notably, nuclear localization of WT1 seemed to be normalized, and nephrin mRNA and protein levels returned near the basal level 72 h post-LPS challenge. During LPS-mediated sepsis, there was a transient increase in blood interleukin-1β, a suppressor of nephrin production in podocytes. Therefore, down-regulation of nephrin by the loss in nuclear WT1, along with hyper-cytokinemia, may underlie the mechanisms by which albuminuria is induced by infectious stresses. - Takashi Kato; Tsutomu Miki Kurosawa; Makoto Mark TaketoRenal failure 31 3 229 - 38 2009年 [査読有り]
ICGN/Oa mice are used to study the pathophysiological mechanisms underlying proteinuria-induced chronic kidney disease (CKD). Recently, a mutation of tensin2 gene (Tns2) was suggested to be responsible for proteinuria in the inbred ICGN mice. We identified the wild-type (+/+), heterozygous (+/nep), and homozygous (nep/nep) ICGN/Oa mice by PCR assay. The homozygotes developed proteinuria, resulting in nephrotic syndrome (NS) as early as 5 weeks and CKD by 15 weeks. However, the heterozygotes did not show the symptoms of these renal failures. These results indicate that the homozygous tensin2 mutation is necessary for the ICGN/Oa mice to develop proteinuria-induced CKD. Furthermore, we examined the time course of tubulointerstitial fibrosis and the kinetics of tubular epithelial cells (TECs) in the ICGN/Oa mice using immunohistochemical and TUNEL assays. In the renal parenchyma of the five-week-old homozygotes, the expression of alpha-SMA and type I collagen were higher than those in the age-matched wild-type. Additionally, increased TEC proliferation was found at 5 weeks, and increased TEC apoptosis was by 15 weeks in the homozygotes. Tubulointerstitial fibrosis precedes TEC apoptosis in the proteinuria-induced CKD model mice, and that tubulointerstitial fibrosis may be the triggering event of the disease. - Takashi Kato; Shinya Mizuno; Makoto Mark Taketo; Tsutomu Miki KurosawaBiomedical research (Tokyo, Japan) 29 6 279 - 87 2008年12月 [査読有り]
The prevalence of chronic kidney disease (CKD) is increasing worldwide and proteinuria is a critical prognostic indicator of CKD. Nephrin is produced by podocytes and functions as a slit barrier for inhibition of proteinuria. Nephrin expression is frequently decreased in CKD patients. Nevertheless, the mechanism by which nephrin declines during CKD-related pathological states remains to be determined. Using tensin2-deficient mice (ICGN/Oa strain), we provide evidence that tensin2 is important for glomerular nephrin expression in vivo. In heterozygous mice with a single mutated tensin2 allele, nephrin expression was maintained, while albuminuria was not observed. In contrast, nephrin expression was impaired, especially in the central zones of glomeruli of homozygous mice (with double mutated tensin2 alleles), even at one week after birth. In homozygous mice, extension of synaptopodin, a key actin-associated protein, was also suppressed in the central zone of glomerular tufts. Consistent with the loss of nephrin and synaptopodin expression, severe albuminuria was detected in homozygous ICGN/Oa mice. Therefore, we suggested that tensin2 is involved in expression and extension of nephrin, while tensin2 deficiency may result in proteinuria, associated with the loss of slit integrity.
MISC
- Takashi Kato; Man Hagiyama; Akihiko Ito Frontiers in cell and developmental biology 6 153 -153 2018年 [査読有り]
- Takashi Kato Biomedical reports 7 (6) 495 -503 2017年12月 [査読有り]
- Dinuka M De Silva; Arpita Roy; Takashi Kato; Fabiola Cecchi; Young H Lee; Kunio Matsumoto; Donald P Bottaro Biochemical Society transactions 45 (4) 855 -870 2017年08月 [査読有り]
共同研究・競争的資金等の研究課題
- 日本学術振興会：科学研究費助成事業研究期間 : 2014年04月 -2016年03月代表者 : 加藤 貴史不死化したヒト肺上皮細胞株HBE135E6E7細胞を肺組織由来ヒト線維芽細胞(MRC-9)とマトリゲル中で三次元培養し、細気管支／肺胞構造に類似した房状分枝構造を作出した。線維芽細胞ではHGFの発現が顕著に高いため、HGF中和抗体を加えると、モデル構造が抑制された。またチロシンリン酸化Metに関しては低分化型腺癌より高分化型腺癌で、より多く陽性症例が見出した。つまり、非浸潤性肺腺癌ではHGFが形態形成に関与している。さらに、肺組織特異的幹細胞であるBASCでのMetの発現は非常に高いことが分かった。そしてBASC、ATII細胞からATI細胞へと分化していくとMetの発現が減少していた。