Abstract
MicroRNAs (miRNAs or miRs) are commonly involved in regulating myocardial ischemia/reperfusion (I/R) injury by binding and silencing their target genes. However, whether miRNAs regulate myocardial I/R-induced pyroptosis remains unclear. The present study established an in vivo rat model of myocardial I/R injury and in vitro hypoxia/reoxygenation (H/R) injury model in rat primary cardiomyocytes to investigate the function and the underlying mechanisms of miRNAs on I/R injury-induced pyroptosis. RNA sequencing was utilized to select the candidate miRNAs between normal and I/R group. Reverse transcription-quantitative PCR and western blotting were performed to detect candidate miRNAs (miR-30c-5p, also known as miR-30c) and SRY-related high mobility group-box gene 9 (SOX9) expression, as well as expression of pyroptosis-associated proteins (NF-κB, ASC, caspase-1, NLRP3) in the myocardial I/R model. ELISA was used to measure pyroptosis-associated inflammatory markers IL-18 and IL-1β. Moreover, the link between miR-30c and SOX9 was predicted using bioinformatics and luciferase reporter assay. In myocardial I/R injured rats, miR-30c was downregulated, while the expression of SOX9 was upregulated. Overexpression of miR-30c inhibited pyroptosis both in vivo and in vitro. Furthermore, miR-30c negatively regulated SOX9 expression by binding its 3'untranslated region. In conclusion, the miR-30c/SOX9 axis decreased myocardial I/R injury by suppressing pyroptosis, which may be a potential therapeutic target.