MicroRNA302-367-PI3K-PTEN-AKT-mTORC1 pathway promotes the development of cardiac hypertrophy through controlling autophagy.

Cardiac hypertrophy at a decompensated state eventually leads to heart failure that mostly contributes to deaths globally. Dysregulated cardiac autophagy is a hallmark of a diseased heart, and a close contact between cardiac autophagy and cardiac hypertrophy is emerging. MicroRNAs (miRNAs) have been recently reported to be prominently implicated in cardiac hypertrophy through regulating cardiac autophagy. However, the role and function of miR302-367 clusters in cardiac autophagy and cardiac hypertrophy remain largely masked. Therefore, to investigate the performance of miR302-367 in cardiac hypertrophy, the specific in vitro hypertrophic model was established in H9c2 cells upon Ang II treatment. Consequently, we discovered a distinct inhibition on autophagy and a remarkable upregulation of miR302-367 expression in hypertrophic H9c2 cells. Besides, loss- and gain-of-function assays demonstrated miR302-367 inhibited autophagy and then aggravated cardiac hypertrophy. Mechanically, PTEN was predicted and confirmed as the shared target of miR302-367. Further, we recognized the apparent inactivation of PI3K/AKT/mTORC1 signaling in the face of miR302-367 suppression in Ang II-induced hypertrophic H9c2 cells. Moreover, co-treatment of PTEN inhibitor re-activated the PI3K/AKT/mTORC1 pathway, therefore counteracting the pro-autophagic and anti-hypertrophic effects of miR302-367 depletion on cardiomyocytes. These findings unveiled the pivotal role of the miR302-367 cluster in regulating cardiac autophagy and therefore modulating cardiac hypertrophy through PTEN/PI3K/AKT/mTORC1 signaling, indicating a promising therapeutic strategy for cardiac hypertrophy and even heart failure. Graphical abstract .