Abstract
miRNAs have been implicated in processing of cardiac hypoxia/reoxygenation (H/R)-induced injury. Recent studies demonstrated that miR-19a might provide a potential cardioprotective effect on myocardial disease. However, the effect of miR-19a in regulating myocardial ischemic injury has not been previously addressed. The present study was to investigate the effect of miR-19a on myocardial ischemic injury and identified the potential molecular mechanisms involved. Using the H/R model of rat cardiomyocytes H9C2 in vitro, we found that miR-19a was in low expression in H9C2 cells after H/R treatment and H/R dramatically decreased cardiomyocyte viability, and increased lactate dehydrogenase (LDH) release and cardiomyocyte apoptosis, which were attenuated by co-transfection with miR-19a mimic. Dual-luciferase reporter assay and Western blotting assay revealed that PTEN was a direct target gene of miR-19a, and miR-19a suppressed the expression of PTEN via binding to its 3'-UTR. We further identified that overexpression of miR-19a inhibited the expression of PTEN at the mRNA and protein levels. Moreover, PTEN was highly expressed in H/R H9C2 cells and the apoptosis induced by H/R was associated with the increase in PTEN expression. Importantly, miR-19a mimic significantly increased p-Akt levels under H/R. In conclusion, our findings indicate that miR-19a could protect against H/R-induced cardiomyocyte apoptosis by inhibiting PTEN /PI3K/p-Akt signaling pathway.