MicroRNA-208a Correlates Apoptosis and Oxidative Stress Induced by H₂O₂ through Protein Tyrosine Kinase/Phosphatase Balance in Cardiomyocytes

Abstract

MicroRNAs, a class of small and non-encoding RNAs that transcriptionally or post-transcriptionally modulate the expression of their target genes, have been implicated as critical regulatory molecules in ischemia-/reperfusion-induced cardiac injury. In the present study, we report on the role of miR-208a in myocardial I/R injury and the underlying cardio-protective mechanism. The gain-of-function and loss-of-function were used to explore the effects of miR-208a on cardiac injury induced by H₂O₂ in cardiomyocytes. As predicted, knockdown of endogenous miR-208a significantly decreased the level of cellular reactive oxygen species (ROS) and reduced cardiomyocyte apoptosis. In addition, miR-208a overexpression increased the ROS level and attenuated cell apoptosis in cardiomyocytes. Furthermore, protein tyrosine phosphatase receptor type G (PTPRG) and protein tyrosine phosphatase, non-receptor type 4 (PTPN4), which participate in regulating the level of cellular protein tyrosine phosphorylation balance, were predicted and verified as potential miR-208a targets using bioinformatics and luciferase assay. In summary, this study demonstrated that miR-208a plays a critical protective role in ROS-induced cardiac apoptosis.