MicroRNA-217-5p ameliorates endothelial cell apoptosis induced by ox-LDL by targeting CLIC4.

Abstract Background and aims Endothelial cell apoptosis plays an essential role in the pathogenesis of atherosclerosis. MicroRNAs and chloride intracellular channels (CLICs) have been verified to participate in the endothelial cell apoptosis process, however, the underlying molecular mechanisms are still unclear. The main aim of this study was to investigate the biological effects of microRNA-217-5p (miR-217-5p) and CLIC4 on endothelial cell apoptosis in atherosclerosis. Methods and results An atherosclerotic mouse model (n = 18) was constructed by feeding apolipo protein E knockout ApoE(−/−) mice with high-fat diet for 12 weeks. An atherosclerotic cell model was established by treating human aortic endothelial cells with oxidized low-density lipoprotein (ox-LDL; 50 μg/mL) for 24 h. Quantitative real-time polymerase chain reaction and immunofluorescent staining confirmed the downregulation of miR-217-5p and upregulation of CLIC4 in atherosclerotic endothelial cells. Combined with western blot, flow cytometry assay and Hoechst staining, we demonstrated that miR-217-5p upregulation or CLIC4 knockdown regulated the apoptosis-related genes, ameliorated mitochondrial membrane permeability and therefore inhibited the apoptosis of aortic endothelial cells induced by ox-LDL. We further confirmed that miR-217-5p inhibited apoptosis of endothelial cells through targeting CLIC4 using luciferase report assay and rescue experiments. Conclusion We revealed for the first time that miR-217-5p inhibited apoptosis of endothelial cells in atherosclerosis and identified CLIC4 as a novel target of miR-217-5p. Our work provides a potential therapeutic approach for the treatment of atherosclerosis.