Synaptotagmin-1 attenuates myocardial programmed necrosis and ischemia/reperfusion injury through the mitochondrial pathway

-challenged cardiomyocytes and hypoxia/reoxygenation (H/R)-damaged cardiomyocytes. Enforced expression of Syt1 significantly inhibited myocardial necrotic cell death and interstitial fibrosis, and improved cardiac function in mice subjected to I/R operation. In exploring the underlying mechanisms, we found that Syt1 interacted with Parkin and promoted Parkin-catalyzed CypD ubiquitination, thus inhibited mitochondrial membrane permeability transition pore (mPTP) opening and ultimately suppressed cardiomyocyte necrosis. We further found that Syt1 expression was negatively regulated by miR-193b-3p. MiR-193b-3p regulated cardiomyocyte necrosis and mPTP opening by targeting Syt1. Our present work revealed a novel regulatory model of myocardial necrosis composed of miR-193b-3p, Syt1, Parkin, and CypD, which may provide potential therapeutic targets and strategies for heart protection.