Circ_0010729 regulates hypoxia-induced cardiomyocyte injuries by activating TRAF5 via sponging miR-27a-3p.

Ischemic cardiomyopathy is a severe cardiovascular disease with high mortality. Circular RNAs (circRNAs) are widely regulated in diverse human diseases, including Ischemic cardiomyopathy. This study aimed to investigate a novel functional mechanism of circRNA circ_0010729 in hypoxia-induced cardiomyocyte injuries. Human cardiomyocytes (AC16) were exposed to hypoxia to mimic ischemic cardiomyopathy in vitro. Cell viability, apoptosis/necrosis and glycolysis progress, were determined using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay, flow cytometry assay and glycolysis stress test, respectively. Cell apoptosis was also assessed by the activity of cleaved caspase-3/7. The levels of glycolysis-related proteins and tumor necrosis factor receptor-associated factor 5 (TRAF5) were examined by western blot. The expression of circ_0010729 and miR-27a-3p was measured by real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The prediction about the targeted relationship was verified by dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay and RNA pull-down assay. As a result, hypoxia treatment inhibited cell viability, induced cell apoptosis and blocked glycolysis, however, these injuries were alleviated by circ_0010729 knockdown. MiR-27a-3p was targeted by circ_0010729, and miR-27a-3p inhibition reversed the role of circ_0010729 knockdown, leading to the deterioration of cell injuries. Further, TRAF5 was a target of miR-27a-3p, and circ_0010729 upregulated the expression of TRAF5 by sponging miR-27a-3p. MiR-27a-3p restoration enhanced cell viability, depleted cell apoptosis and promoted glycolysis of hypoxia-induced AC16 cells, while these effects were abolished by TRAF5 overexpression. In conclusion, circ_0010729 knockdown alleviated hypoxia-induced AC16 cell injuries by mediating the miR-27a-3p/TRAF5 axis.