miRNA-30 family inhibition protects against cardiac ischemic injury by regulating cystathionine-γ-lyase expression.

Myocardial infarction (MI) is a leading cause of death globally. MicroRNAs (miRNAs) have been identified as a novel class of MI injury regulators. Hydrogen sulfide (H2S) is a gaseous signaling molecule that regulates cardiovascular function. The purpose of this study was to explore the role of the miR-30 family in protecting against MI injury by regulating H2S production. The expression of miR-30 family was upregulated in the murine MI model as well as in the primary cardiomyocyte hypoxic model. However, the cystathionine-γ-lyase (CSE) expression was significantly decreased. The overexpression of miR-30 family decreased CSE expression, reduced H2S production, and then aggravated hypoxic cardiomyocyte injury. In contrast, silencing the whole miR-30 family can protect against hypoxic cell injury by elevating CSE and H2S level. Nonetheless, the protective effect was abolished by cotransfecting with CSE-siRNA. Systemic delivery of a locked nucleic acid (LNA)-miR-30 family inhibitor correspondingly increased CSE and H2S level, then reduced infarct size, decreased apoptotic cell number in the peri-infarct region, and improved cardiac function in response to MI. However, these cardioprotective effects were absent in CSE knockout mice. MiR-30b overexpression in vivo aggravated MI injury because of H2S reduction, and this could be rescued by S-propargyl-cysteine (SPRC), which is a novel modulator of CSE, or further exacerbated by propargylglycine (PAG), which is a selective inhibitor of CSE. Our findings reveal a novel molecular mechanism for endogenous H2S production in the heart at the miRNA level and demonstrate the therapeutic potential of miR-30 family inhibition for ischemic heart diseases by increasing H2S production.