Abstract 221: miR-19b Protects Myocardial Ischemia Reperfusion Injury

Ischemia-reperfusion injury (IRI) following acute myocardial infarction (AMI) has no effective treatment and a poor prognosis. microRNA (miRNA)-19b is a key functional member of miRNA-19-72 cluster family, regulating cellular proliferation, apoptosis, differentiation, and metabolism. Dysregulation of the miR-19b cluster is critically involved in a spectrum of cardiovascular diseases. However, the role of miR-19b in myocardial IRI is unknown. In this study, we found that miR-19b was downregulated in a mouse model of IRI. Meanwhile, about 50% downregulation of miR-19b was detected in H2O2-treated H9C2 cells mimicking myocardial IRI. We also found that overexpression of miR-19b decreased H2O2-induced apoptosis (36.02%±3.92% vs 29.34%±0.79% in nc-mimics vs miR-19b-mimics, respectively) and necrosis (23.11%±1.64% vs 18.76%±0.71% in nc-mimics vs miR-19b-mimics, respectively), and increased proliferation of H9C2 cells in vitro, while downregulation of miR-19b had reverse effects. Furthermore, PTEN, a previously validated target gene of miR-19b, has been found to be negatively regulated by miR-19b at protein levels in H9C2 cells. These data reveal the potential of miR-19b as a therapeutic target for myocardial IRI.