MicroRNA-204 protects H9C2 cells against hypoxia/reoxygenation-induced injury through regulating SIRT1-mediated autophagy.

Ischemia/reperfusion (I/R) injury is a main cause of acute myocardial infarction, and the pathogenesis of I/R injury is still not definitely confirmed. In the present study, we aimed to explore the roles of miR-204 in hypoxia/reoxygenation (H/R)-induced cardiomyocyte injury in vitro. The H9C2 cells were subjected to hypoxia for 12 h followed by reoxygenation for another 24 h, and we found that miR-204 was significantly down-regulated after H/R treatment. Transfection of miR-204 mimics attenuated the H/R-induced impaired cell viability and increased apoptosis rates. Furthermore, SIRT1 was identified as a direct target of miR-204, and its expression is negatively regulated by miR-204. Forced expression of SIRT1 could partly rescue the effects of miR-204 on H/R-induced apoptosis and autophagy. Taken together, our study first revealed that overexpression of miR-204 has a protective effect against myocardial I/R injury.