Screening and Function Analysis of MicroRNAs Involved in Exercise Preconditioning-Attenuating Pathological Cardiac Hypertrophy.

Exercise preconditioning (EP) attenuates pathological cardiac hypertrophy by increasing the functional capacity of the cardiovascular system; however, the underlying molecular mechanisms remain unclear. MicroRNAs (miRNAs) play important roles in various physiological and pathological processes by regulating the expression of the targeted gene. In this study, we aimed to screen the miRNAs involved in EP-attenuating pathological cardiac hypertrophy. The histological and echocardiographic parameters assessment showed that pathological cardiac hypertrophy induced by transverse aortic constriction (TAC) was significantly alleviated in EP treated rats. The left ventricular tissues (n = 3) from Sham, TAC and EP + TAC groups were subjected to small RNA deep sequencing. A total of 570 known mature miRNAs and 530 putative novel miRNAs were detected. DEGseq analysis showed that there were 37 and 88 differentially expressed miRNAs in the comparisons of TAC versus Sham and EP + TAC versus TAC, respectively. Among them, EP treatment could relieve the expression changes of 32 miRNAs, which were supposed to be involved in EP-attenuating pathological cardiac hypertrophy. After miRNAs target genes prediction by miRDB algorithm, pathway analysis showed that the most frequently represented pathways were involved in Calcium signaling pathway and MAPK signaling pathway. The results would provide valuable clues to finding therapeutic targets for the treatment of pathological cardiac hypertrophy.