The molecular mechanism of MiR-26a-5p regulates excessive autophagy and activates NLRP3 inflammasome to mediate cardiomyocyte hypertrophy

Abstract

Abstract Objective: Many studies have found that miR-26a-5p plays an essential role in the progression of pathological cardiac hypertrophy, but whether the role of miR-26a-5p is related to the regulation of autophagy leading to activation of NLRP3 inflammasome. And the mechanism of miR-26a-5p and NLRP3 inflammasome aggravating pathological cardiac hypertrophy remain unclear. Methods: Cardiomyocytes were treated with 200μM PE to induce cardiac hypertrophy and intervened with 10mM NLRP3 inhibitor INF39. In addition, we also used the pLL3.7 lentiviral vector to construct sh-RNA-miR-26a-5p interference plasmid and PLL3.7-cmv-miR-26a-5p overexpression plasmid to transfect PE-induced cardiac hypertrophy. RT-qPCR and western blotting were used to detect the expressions of miR-26a-5p, NLRP3, ASC and Caspase-1 in each group, and we used α-SMA immunofluorescence to detect changes in the cardiomyocyte area. The expression levels of autophagy proteins LC3, beclin-1 and p62 were detected by western blotting. Finally, we induced the SD rat cardiac hypertrophy model through aortic constriction (TAC) surgery. In the experimental group, rats were intervened with miR-26a-5p overexpression lentivirus, miR-26a-5p interference lentivirus, autophagy inhibitor 3-MA, and autophagy activator Rapamycin. Results:In cell experiments, the expression of miR-26a-5pwas associated with cardiomyocyte hypertrophy and increased surface area. In addition, miR-26a-5ppromoted autophagy and NLRP3 inflammasome pathway activation, increasing or decreasing the gene and protein expression of LC3, Bclin1, p62, ACS, NLRP3, and Caspase-1. We found similar results in the TAC rat model, where miR-26a-5pexpression was associated with cardiomyocyte enlargement and cardiac interstitial and perivascular fibrosis. miR-26a-5p adenovirus transfection regulates the activation of the NLRP3 pathway. Conclusion: Our research observed the expression of miR-26a-5p is related to cardiomyocyte hypertrophy, and its mechanism may be associated with the activation of the NLRP3 inflammasome pathway caused by miR-26a-5p's excessive promotion of autophagy. Therefore, targeting the expression of miR-26a-5p, inhibiting the activation of autophagy and NLRP3 inflammasome pathway, may bring more options for treating pathological cardiac hypertrophy.