miR-378a-3p inhibits ischemia/reperfusion-induced apoptosis in H9C2 cardiomyocytes by targeting TRIM55 via the DUSP1-JNK1/2 signaling pathway
Jiaying Tan, Jun Shen, Huigeng Zhu, Ye Gong, Hechen Zhu, Junping Li, Shan Lin, Gang Wu, Tao Sun
Abstract
MicroRNAs (miRNAs) are involved in many pathological and biological processes, such as ischemia/reperfusion (I/R) injury by modulating gene expression. Increasing evidence indicates that miR-378a-3p might provide a potential cardioprotective effect against ischemic heart disease. Cell apoptosis is a crucial mechanism in I/R injury. As such, this study evaluated the protective effects and underlying mechanisms of action of miR-378a-3p on H9C2 cardiomyocyte apoptosis following I/R injury. We found that I/R-induced H9C2 cardiomyocytes exhibited a decrease in miR-378a-3p expression, while treatment with a miR-378a-3p mimic suppressed cell apoptosis, JNK1/2 activation, cleavage of PARP and caspase-3, and Bax/Bcl-2 ratio but increased DUSP1 expression, which subsequently inhibited JNK1/2 phosphorylation. TRIM55 was shown to be a target of miR-378a-3p and its downregulation inhibited the miR-378a-3p inhibitor-induced increase in cell apoptosis and JNK1/2 activation. TRIM55 inhibited DUSP1 protein expression through ubiquitination of DUSP1. Moreover, DUSP1 overexpression inhibited the TRIM55 overexpression-induced increase in cell apoptosis and JNK1/2 activation. The protective effect of miR-378a-3p was subsequently confirmed in a rat myocardial I/R model, as evidenced by a decrease in cardiomyocyte apoptosis of cardiomyocytes, TRIM55 expression, and JNK1/2 activation. Taken together, these results suggest that miR-378a-3p may protect against I/R-induced cardiomyocyte apoptosis via TRIM55/DUSP1/JNK signaling.