Exercise protects the heart against myocardial infarction through upregulation of miR-1192.

Myocardial infarction (MI) is known as a serious global problem, which has a high mortality rate and cause severe heart damage. Mounting evidence has suggested that exercise provides direct endogenous cardiac protection against various cardiovascular diseases including MI. However, the underlying mechanism of exercise's cardioprotective effect against MI has not been fully understood. Here, we found that a 4-wk swim training exerted protective effects against MI in C57 mice, as evidenced by increased cardiac function and decreased cardiac apoptosis. A plasma miRNA profiling assay was then performed, and 10 differentially expressed miRNAs were detected. Among them, miR-1192 was increased after exercise, and it exerted significant protective effect against hypoxia in cultured neonatal cardiomyocytes. In addition, intramyocardially injection of agomiR-1192 exerted similar cardioprotective effect as exercise, and inhibition of miR-1192 using antgomiR-1192 abolished the cardioprotective effect of exercise in MI mice, suggesting that exercise exerted cardioprotection against MI through upregulation of miR-1192. Furthermore, we found that miR-1192 exerted cardioprotective effect via targeting caspase 3 in cardiomyocytes. These findings suggested that exercise protects the heart against MI through upregulation of miR-1192, and miR-1192 is a novel exerkine in exercise-induced cardioprotection against MI.