MicroRNA‐494 regulates high glucose‐induced cardiomyocyte apoptosis and autophagy by PI3K/AKT/mTOR signalling pathway

Abstract Aims Diabetic cardiomyopathy (DCM) is one of the major cardiovascular complications of diabetes. However, the mechanism of DCM is not fully understood. Studies have confirmed that certain microRNAs (miRNAs/miRs) are key regulators of DCM. The aim of this study was to investigate the role and mechanism of microRNA (miR)‐494 in cardiomyocyte apoptosis and autophagy induced by high glucose (HG). Methods and results By establishing a rat DCM model and an HG‐treated H9c2 cells injury model, cardiac function was detected by echocardiography, myocardial tissue was stained by immunohistochemistry, and Cell Counting Kit‐8 assay and lactate dehydrogenase assay were used to detect the cardiomyocyte injury. Cell apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick end labelling staining, and western blotting was used to detect death and autophagy. The results showed that the expression level of miR‐494 was higher in the myocardial tissue of DCM rats and the myocardial cells of H9c2 treated with HG. Compared with the corresponding negative control groups, miR‐494 mimics enhanced HG‐induced apoptosis and autophagy, whereas miR‐494 inhibitors showed the opposite effect, corresponding PI3K, AKT, and mTOR phosphorylation level has changed. Conclusions These findings identify that miR‐494 could regulate cell apoptosis and autophagy through PI3K/AKT/mTOR signalling pathway, participating in the regulation of cardiomyocyte cell damage after HG. These findings provide new insights for the further study of the molecular mechanism and treatment of DCM.