Protective Effect of EGCG on Hydrogen Peroxide-induced Apoptosis of Human Cardiomyocyte via Regulating miR-16-5p/AOC1 Axis

Objective: To explore the molecular mechanism driving the tea polyphenol epigallocatechin-3-gallate (EGCG)-exerted protective effect on hydrogen peroxide (H₂O₂)-induced cell apoptosis of human cardiomyocyte HCM cell lines. Methods: HCM cells were stimulated with H₂O₂ to establish a vitro apoptosis model; the caspase-3 assay was used to assess the cell apoptosis of HCM cells; the CCK-8 assay was used to perform the cytotoxicity experiment; qPCR was used to detect the levels of AOC1 mRNA and miR-16-5p; Western blot was used to detect the protein level of AOC1; cells transfection was conducted to regulate the expression levels of AOC1 and miR-16-5p in HCM cells; TargetScan was used to predict the binding relationship and site between AOC1 mRNA 3’UTR and miR-16-5p, which was verified by the double luciferase reporter gene assay. Results: EGCG could significantly inhibit H₂O₂-induced apoptosis of HCM cells (P<0.05). In apoptotic cells, the expression of AOC1 was significantly decreased, and EGCG could significantly up-regulate the expression of AOC1, while knocking down AOC1 could significantly reverse the inhibition of EGCG on apoptosis (P<0.05). Meanwhile, the expression of miR-16-5p was significantly increased in apoptotic cells, and EGCG could significantly inhibit the expression of miR-16-5p, while up-regulation of miR-16-5p significantly reversed the inhibition of EGCG on apoptosis (P<0.05). Upregulation of miR-16-5p significantly reversed the promotion of AOC1 expression by EGCG in apoptotic cells. Finally, miR-16-5p can target inhibit the expression of AOC1, while over expression of AOC1 significantly reversed miR-16-5p-induced apoptosis of HCM cells. Conclusion: EGCG protected H₂O₂-induced apoptosis of HCM cells by regulating the miR-16-5p/AOC1 axis, which proposes AOC1 as a potential novel therapeutic target pro-tection against cardiomyocyte injury.