Canstatin inhibits hypoxia-induced apoptosis through activation of integrin/focal adhesion kinase/Akt signaling pathway in H9c2 cardiomyoblasts

Abstract

A hypoxic stress which causes apoptosis of cardiomyocytes is the main problem in the ischemic heart disease. Canstatin, a non-collagenous fragment of type IV collagen α2 chain, is an endogenous anti-angiogenic factor. We have previously reported that canstatin has a cytoprotective effect on cardiomyoblasts. In the present study, we examined the effects of canstatin on hypoxia-induced apoptosis in H9c2 cardiomyoblasts. Cell counting assay was performed to determine a cell viability. Western blotting was performed to detect expression of cleaved casepase-3 and phosphorylation of focal adhesion kinase (FAK) and Akt. Immunocytochemical staining was performed to observe a distribution of αv integrin. Hypoxia (1% O2, 48 h) significantly decreased cell viability and increased cleaved caspase-3 expression. Canstatin (10–250 ng/ml) significantly inhibited these changes in a concentration-dependent manner. Cilengitide (1 μM), an αvβ3 and αvβ5 integrin inhibitor, significantly prevented the protective effects of canstatin on cell viability. Canstatin significantly increased phosphorylation of FAK and Akt under hypoxic condition, which were inhibited by cilengitide. LY294002, an inhibitor of phosphatidylinositol-3 kinase/Akt pathway, suppressed the canstatin-induced Akt phosphorylation and reversed the protective effects of canstatin. It was observed that hypoxia caused a localization of αv integrin to focal adhesion. In summary, we for the first time clarified that canstatin inhibits hypoxia-induced apoptosis via FAK and Akt pathways through activating integrins in H9c2 cardiomyoblasts.

RETRACTED ARTICLE: Downregulation of miR-483-5p decreases hypoxia-induced injury in human cardiomyocytes by targeting MAPK3

“…Acute myocardial infarction (AMI) is a type of coronary artery disease with high mortality and morbidity worldwide [1]. Its occurrence is usually associated with acute continuous hypoxia-induced cardiomyocyte apoptosis and oxidative stress in coronary arteries [2]. In other words, hypoxia could promote myocardial cell apoptosis, induce reactive oxygen species (ROS) generation, and decrease the activity of antioxidant enzymes, including glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT), aggravating the conditions of AMI [3,4].…”

New Insights into the Role of Basement Membrane-Derived Matricryptins in the Heart

“…Recently, we clarified that canstatin prevents isoproterenol-induced apoptosis through the inhibition of mitochondrial fission by suppressing the dephosphorylation of dynamin related protein 1 at Ser637 in differentiated H9c2 cardiomyoblasts. 63) We also found in H9c2 cardiomyoblasts that canstatin suppressed hypoxia-induced apoptosis though the activation of the focal adhesion kinase (FAK)/Akt signaling pathway by binding α v β 3 and/or α v β 5 integrin. 64) Furthermore, it has been shown that canstatin stimulates the migration of cardiac fibroblasts by the secretion of MMP-2, 65) and that it promotes the proliferation and secretion of MMPs, as well as inhibits collagen gel contraction in myofibroblasts derived from the infarcted area of the myocardial infarction model rat.…”

“…On the other hand, canstatin exerts a cytoprotective effects against cell death-inducing stress. 63,64) An active fragment of tumstatin, the T3 peptide, also prevents oxidative stress-induced apoptosis 81) in H9c2 cardiomyoblasts. From experiments using a neutralizing antibody, 114) endostatin is supposed to have a cardioprotective effect.…”

Kaji-Ichigoside F1 and Rosamultin Protect Vascular Endothelial Cells against Hypoxia-Induced Apoptosis via the PI3K/AKT or ERK1/2 Signaling Pathway

“…The expression of HIF-1α and phosphorylation of key molecules, such as ERK1/2, AKT, and NF-κB, increase during hypoxia, indicating activation of protective signaling pathways including MAPK, PI3K/AKT, HIF-1, and NF-κB [40][41][42]. These pathways participate in the regulation of mitochondrial apoptosis and effectively inhibit apoptosis [43].…”