Regulatory Mechanism of circEIF4G2 Targeting miR-26a in Acute Myocardial Infarction

BACKGROUND: Acute myocardial infarction (AMI) involves a series of complex cellular and molecular events, including circular RNAs (circRNAs), microRNAs (miRNAs) and other noncoding RNAs. OBJECTIVE: In this study, the regulation mechanism of circEIF4G2 acting on miR-26a on HUVECs (Human Umbilical Vein Endothelial Cells) proliferation, cell cycle and angiogenesis ability was mainly explored in the vascular endothelial growth factor induced (VEGF-induced) angiogenesis model. METHODS: VEGF induced HUVECs angiogenesis model was constructed, and the expression of circEIF4G2 and miR-26a in VEGF model was detected by qRT-PCR. When circEIF4G2 and miR-26a were knocked down or overexpressed in HUVECs, qRT-PCR was used to detect the expression of circEIF4G2 and miR-26a, CCK-8 was used to detect cell proliferation, flow cytometry was used to detect the cell cycle transition of HUVECs, and cell formation experiment was used to detect the ability of angiogenesis. MiRanda database and Targetscan predicted the binding site of circEIF4G2 and miR-26a, lucifase reporting assay and RNA pull down assay verified the interaction between circEIF4G2 and miR-26a. RESULTS: After HUVECs were treated with VEGF, circEIF4G2 was significantly upregulated. After circEIF4G2 was knocked down, the proliferation and angiogenesis of HUVECs cells were decreased, and the process of cell cycle G0/G1 phase was blocked. The overexpression of miR-26a reduced the proliferation and angiogenesis of HUVECs cells and blocked the cell cycle progression of G0/G1 phase. Double lucifase reporter gene assay verified that circEIF4G2 could directly interact with miR-26a through the binding site, and RNA Pull down assay further verified the interaction between circEIF4G2 and miR-26a. When circEIF4G2 and miR-26a were knocked down simultaneously in HUVECs, it was found that knocking down miR-26a could reverse the inhibition of circEIF4G2 on cell proliferation, cycle and angiogenesis. CONCLUSION: In the VEGF model, circEIF4G2 was highly expressed and miR-26a was low expressed. MiR-26a regulates HUVECs proliferation, cycle and angiogenesis by targeting circEIF4G2.