The mechanism by which miR-494-3p regulates PGC1-α-mediated inhibition of mitophagy in cardiomyocytes and alleviation of myocardial ischemia-reperfusion injury

• Published in: BMC cardiovascular disorders 2023-04, Vol.23 (1), p.204-204, Article 204
• Main Authors: Mu, Ninghui, Zhang, Tong, Zhu, Ying, Lu, Bingtuan, Zheng, Qi, Duan, Jinlan
• Format: Article
• Language: English
• Subjects: Animals; Apoptosis; Autophagy; BAX protein; Bcl-2 protein; Beclin-1 - metabolism; Biosynthesis; Cardiomyocyte; Cardiomyocytes; Cell proliferation; Cells; Cholecystokinin; Flow cytometry; Gene flow; Heart attacks; Hypoxia; Hypoxia - metabolism; Ischemia; Membrane potential; MicroRNAs; MicroRNAs - genetics; MicroRNAs - metabolism; miR-494-3p; Mitochondria; Mitophagy; Mitophagy - genetics; Myocardial ischemia; Myocardial ischemia–reperfusion injury; Myocardial Reperfusion Injury - genetics; Myocardial Reperfusion Injury - metabolism; Myocytes, Cardiac - metabolism; Parkin protein; Permeability; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha - metabolism; PGC1-α; Phagosomes; Plasmids; Protein Kinases - metabolism; Proteins; PTEN-induced putative kinase; Rats; Regulation; Reperfusion; Signal transduction; Transfection; Transmission electron microscopy; Western blotting
• ISSN: 1471-2261; 1471-2261
• DOI: 10.1186/s12872-023-03226-7

The purpose of this study was to explore whether miR-494-3p inhibits the occurrence of mitochondrial autophagy in cardiomyocytes by inhibiting the expression of PGC1-α and to supplement the theoretical basis for the role of autophagy in cardiac injury induced by hypoxia/reperfusion (H/R). The expression of miR-494-3p was detected by RT‒qPCR, and the expression of PGC1-α, autophagy-related proteins (LC3, Beclin 1), apoptosis-related proteins (Bax and Bcl-2), PINK1/Parkin signaling pathway-related proteins (PINK1, Parkin) and mitochondrial change-related proteins (Mfn1, Mfn2, OPA1) was detected by Western blotting. The changes in mitochondrial membrane potential were detected by JC-1 staining (ΔΨm). The formation of autophagosomes was observed by transmission electron microscopy. Cell proliferation activity was detected by CCK-8, and cell apoptosis was detected by flow cytometry. A dual-luciferase gene reporter assay identified a targeted binding site between miR-494-3p and PGC1-α. The results showed that miR-494-3p and PGC1-α were differentially expressed in H/R cardiomyocytes; that is, the expression of miR-494-3p was downregulated, and the expression of PGC1-α was upregulated. In addition, mitochondrial autophagy occurred in H/R cardiomyocytes. That is, LC3-II/LC3-I, Beclin 1, PINK1, and Parkin expression was upregulated, Mfn1, Mfn2, and OPA1 expression was downregulated, and the mitochondrial membrane potential was decreased. The transfection of miR-494-3p mimic can significantly improve the cell proliferation activity of cardiomyocytes and inhibit the occurrence of cardiomyocyte apoptosis and autophagy, while the transfection of miR-494-3p inhibitor has the opposite result. After transfection of the miR-494-3p mimic, treatment with autophagy inhibitors and activators changed the effects of miR-494-3p on cardiomyocyte proliferation and apoptosis. At the same time, the overexpression of PGC1-α reversed the promoting effect of miR-494-3p on cardiomyocyte proliferation and the inhibitory effect on apoptosis and autophagy. MiR-494-3p can target and negatively regulate the expression of PGC1-α to inhibit mitophagy in cardiomyocytes.