miR-145-5p targets paxillin to attenuate angiotensin II-induced pathological cardiac hypertrophy via downregulation of Rac 1, pJNK, p-c-Jun, NFATc3, ANP and by Sirt-1 upregulation.

Pathological cardiac hypertrophy is associated with many diseases including hypertension. Recent studies have identified important roles for microRNAs (miRNAs) in many cardiac pathophysiological processes, including the regulation of cardiomyocyte hypertrophy. However, the role of miR-145-5p in the cardiac setting is still unclear. In this study, H9C2 cells were overexpressed with microRNA-145-5p, and then treated with Ang-II for 24 h, to study the effect of miR-145-5p on Ang-II-induced myocardial hypertrophy in vitro. Results showed that Ang-II treatment down-regulated miR-145-5p expression were revered after miR-145-5p overexpression. Based on results of bioinformatics algorithms, paxillin was predicted as a candidate target gene of miR-145-5p, luciferase activity assay revealed that the luciferase activity of cells was substantial downregulated the following co-transfection with wild paxillin 3'UTR and miR-145-5p compared to that in scramble control, while the inhibitory effect of miR-145-5p was abolished after transfection of mutant paxillin 3'UTR. Additionally, overexpression of miR-145-5p markedly inhibited activation of Rac-1/ JNK /c-jun/ NFATc3 and ANP expression and induced SIRT1 expression in Ang-II treated H9c2 cells. Jointly, our study suggested that miR-145-5p inhibited cardiac hypertrophy by targeting paxillin and through modulating Rac-1/ JNK /c-jun/ NFATc3/ ANP / Sirt1 signaling, therefore proving novel downstream molecular pathway of miR-145-5p in cardiac hypertrophy.