GAS5 promotes myocardial apoptosis in myocardial ischemia-reperfusion injury via upregulating LAS1 expression.

OBJECTIVE: This study aims at investigating whether GAS5 (grow arrest-specific 5) could promote cardiomyocyte apoptosis by upregulating LAS1 expression, thereby participating in the development of myocardial ischemia-reperfusion injury. MATERIALS AND METHODS: The expression level of GAS5 in H9c2 cells after hypoxia/reoxygenation (H/R) treatment was detected by quantitative Real time-polymerase chain reaction (qRT-PCR). Myocardial injury markers in H9c2 cells were evaluated using relative commercial kits, including activities of LDH (lactate dehydrogenase), MDA (malondialdehyde), SOD (superoxide dismutase) and GSH-PX (glutathione peroxidase). Cell proliferation and apoptosis were detected by cell counting kit-8 (CCK-8) assay and flow cytometry, respectively. The protein expressions of apoptosis-related genes and p38/MAPK pathway-related genes were detected by Western blot. The regulatory effects of GAS5 on the p38/MAPK pathway were assessed after treatment with p38/MAPK pathway inhibitor in H9c2 cells. RESULTS: QRT-PCR results showed that the expression levels of GAS5 and LAS1 in H/R-treated H9c2 cells were remarkably upregulated compared to those of controls. GAS5 overexpression increased activities of LDH, MDA, SOD and GSH-PX in H/R-treated H9c2 cells. Meanwhile, GAS5 overexpression reduced cell proliferation and apoptosis of H/R-treated cells. Western blot results suggested that the pro-apoptosis genes Bax and cytochrome C were upregulated, whereas the anti-apoptosis gene Bcl-2 was downregulated after GAS5 overexpression. The overexpression of LAS1 in H9c2 cells obtained the same results as GAS5 overexpression. Furthermore, the expressions of p-p38 and p-ERK were upregulated by GAS5 overexpression. SB203580, the p38/MAPK pathway inhibitor, could reverse the inhibited proliferation and increase apoptosis induced by overexpression of GAS5. CONCLUSIONS: GAS5 promotes myocardial apoptosis in myocardial ischemia-reperfusion injury by upregulating LAS1 expression via p38/MAPK pathway. GAS5 may be a potential therapeutic target for myocardial ischemia-reperfusion injury. [ABSTRACT FROM AUTHOR]