担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

Pathological cardiac hypertrophy associated with cardiac dysfunction is an independent risk factor for arrhythmia, myocardial infarction and sudden death. Canstatin, a C-terminal fragment of type IV collagen α2 chain, is abundantly expressed in normal heart tissue. We previously demonstrated that canstatin inhibits isoproterenol (ISO)-induced dephosphorylation of nuclear factor of activated T-cells (NFAT)c4, which plays an important role in cardiac hypertrophy, in differentiated H9c2 cardiomyoblasts. Thus, we investigated whether in vivo canstatin administration prevents ISO-induced cardiac hypertrophy through the inhibition of NFATc4 pathway. Rats were subcutaneously injected with ISO (5 mg/kg) or saline (Cont) for 7 days. Simultaneously, recombinant mouse canstatin (20 μg/kg) or vehicle was intraperitoneally administered. After left ventricular wall thickness and cardiac function were measured by echocardiography, the hearts were isolated and left ventricular weight (LVW) was weighed. Azan staining was performed to measure cross-sectional diameter of cardiomyocytes. Activity of calcineurin, which dephosphorylates NFATc4, was measured by calcineurin phosphatase activity assay. Immunohistochemical staining was performed to evaluate nuclear translocation of NFATc4. Intracellular Ca2+ concentration in neonatal rat cardiomyocytes (NRCMs) was measured by using a calcium indicator. Canstatin significantly inhibited ISO-induced increase of LVW, left ventricular posterior wall thickness at end-diastole and diameter of cardiomyocytes. Canstatin significantly inhibited ISO-induced activation of calcineurin, nuclear translocation of NFATc4, increased mRNA expression of β-myosin heavy chain and α-skeletal actin, and intracellular Ca2+ rise in NRCMs. In summary, we for the first time demonstrated that canstatin administration suppresses ISO-induced cardiac hypertrophy possibly through the blockade of calcineurin/NFATc4 pathway in rats.

DOI： 10.1016/j.ejphar.2019.172849

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

The basement membrane surrounding cardiomyocytes is mainly composed of α1 and α2 chain of type IV collagen. Arresten and canstatin are fragments of non-collagenous C-terminal domain of α1 and α2 chain, respectively. We previously reported that the expression of canstatin was decreased in infarcted area 2 weeks after myocardial infarction in rats. In the present study, we investigated the regulatory mechanism for expression of arresten and canstatin. Myocardial infarction model rats were produced by ligating left anterior descending artery. Western blotting and immunohistochemical staining were performed to determine the protein expression and distribution. Arresten and canstatin were highly expressed in the heart. One day and three days after myocardial infarction, the expression of arresten and canstatin in infarcted area was lower than that in non-infarcted area. The expression of cathepsin S, which is known to degrade arresten and canstatin, was increased in the infarcted area. A knockdown of cathepsin S gene using small interference RNA suppressed the decline of arresten and canstatin in the infarcted area 3 days after myocardial infarction. This study for the first time revealed that arresten and canstatin are immediately degraded by cathepsin S in the infarcted area after myocardial infarction. These findings present a novel fundamental insight into the pathogenesis of myocardial infarction through the turnover of basement membrane-derived endogenous factors.

DOI： 10.1292/jvms.18-0674

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

Myofibroblasts contribute to the healing of infarcted areas after myocardial infarction through proliferation, migration, and production of extracellular matrix (ECM). Expression of endostatin, a cleaved fragment of type XVIII collagen, increases in the heart tissue of an experimental myocardial infarction model. In the present study, we examined the effect of endostatin on the function of myofibroblasts derived from an infarcted area. The myocardial infarction model was created by ligating the left anterior descending artery in rats. Two weeks after the operation, α-smooth muscle actin (α-SMA)-positive myofibroblasts were isolated from the infarcted area. Endostatin significantly increased the proliferation and migration of myofibroblasts in vitro. On the other hand, endostatin had no effect on the production of type I collagen, a major ECM protein produced by myofibroblasts. Endostatin activated Akt and extracellular signal-regulated kinase (ERK), and the pharmacological inhibition of these signaling pathways suppressed the endostatin-induced proliferation and migration. A knockdown of the COL18A1 gene in the myocardial infarction model rats using small interference RNA (siRNA) worsened the cardiac function concomitant with wall thinning and decreased the α-SMA-positive myofibroblasts and scar formation compared with that of control siRNA-injected rats. In summary, we demonstrated for the first time that endostatin might be an important factor in the healing process after myocardial infarction through the activation of myofibroblasts.

DOI： 10.3390/ijms19030741

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

Myofibroblasts play an important role during remodeling process after myocardial infarction through proliferation, migration, production and degradation of extracellular matrix (ECM) and contraction. Canstatin, a 24kDa polypeptide, is cleaved from α2 chain of type IV collagen, which is a major component of basement membrane around cardiomyocytes. We examined the effects of canstatin on myofibroblasts isolated from the areas of myocardial infarction. Myocardial infarction model was made by ligating left anterior descending artery of Wistar rats. Two weeks after the operation, the cells were isolated by an explant method and identified as myofibroblasts with immunofluorescence staining. Cell counting assay was performed to examine cell proliferation. Boyden chamber assay was performed to examine cell migration. Expression and phosphorylation of proteins were detected by Western blotting. Collagen gel contraction assay was performed to measure cell contractility. Canstatin stimulated proliferation, secretion of matrix metalloproteinases, expression of cyclooxygenase (COX)-2, and inhibited collagen gel contraction in myofibroblasts. Canstatin increased Akt phosphorylation. LY294002, a phosphoinositide-3-kinase/Akt inhibitor, inhibited the canstatin-induced proliferation. NS-398, a COX-2 inhibitor, suppressed the inhibitory effect of canstatin on collagen gel contraction. Canstatin expression in areas of myocardial infarction 2 weeks after surgery decreased. We for the first time demonstrate that canstatin is an endogenous bioactive molecule regulating the various functions of myofibroblasts after myocardial infarction. The decrease of canstatin expression in the maturated areas of myocardial infarction might lead to stabilization of scar tissues perhaps in part through the reduction of proliferation and ECM degradation as well as the stimulation of contractility in myofibroblasts.

DOI： 10.1016/j.ejphar.2017.04.027

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

The extracellular matrix (ECM), which contributes to structural homeostasis as well as to the regulation of cellular function, is enzymatically cleaved by proteases, such as matrix metalloproteinases and cathepsins, in the normal and diseased heart. During the past two decades, matricryptins have been defined as fragments of ECM with a biologically active cryptic site, namely the 'matricryptic site,' and their biological activities have been initially identified and clarified, including anti-angiogenic and anti-tumor effects. Thus, matricryptins are expected to be novel anti-tumor drugs, and thus widely investigated. Although there are a smaller number of studies on the expression and function of matricryptins in fields other than cancer research, some matricryptins have been recently clarified to have biological functions beyond an anti-angiogenic effect in heart. This review particularly focuses on the expression and function of basement membrane-derived matricryptins, including arresten, canstatin, tumstatin, endostatin and endorepellin, during cardiac diseases leading to heart failure such as cardiac hypertrophy and myocardial infarction.

DOI： 10.1248/bpb.b17-00308

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記述言語：英語   会議種別：ポスター発表  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：英語  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：英語   会議種別：ポスター発表  

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記述言語：英語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：英語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：英語   会議種別：ポスター発表  

researchmap

記述言語：英語   会議種別：口頭発表（一般）  

researchmap

記述言語：日本語   会議種別：口頭発表（一般）  

researchmap

記述言語：日本語   会議種別：口頭発表（一般）  

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