CircRSF1 contributes to endothelial cell growth, migration and tube formation under ox-LDL stress through regulating miR-758/CCND2 axis

Compelling evidences demonstrate that informative RNAs play essential role in therapy of atherosclerosis. Here, we attempted to study the role of hsa_circ_0000345 (circRSF1) in endothelial cell damage through competing endogenous RNA pathway. Expression of circRSF1, miRNA-758-3p (miR-758) and cyclin D2 (CCND2) was detected using RT-qPCR and western blotting, and the cross-talk among them was identified using dual-luciferase reporter assay and RNA immunoprecipitation. The low-density lipoprotein cholesterol (LDL-C) level was measured with enzyme-linked immunosorbent assay. Cell growth was measured by MTS assay, flow cytometry and caspase-3 activity assay kit. Migration and tube formation were determined by scratch migration assay and tube formation assay, respectively. CircRSF1 and CCND2 were downregulated, whereas miR-758 was upregulated in serum of patients with atherosclerosis and oxidized low-density lipoprotein (ox-LDL)-treated human aortic endothelial cells (HAECs). Moreover, levels of circRSF1, miR-758 and CCND2 were correlated with circulating LDL-C level. Restoring circRSF1 and silencing miR-758 could improve cell viability, tube formation and migration of HAECs under ox-LDL treatment, as well as attenuated apoptotic rate and caspase-3 activity. However, miR-758 upregulation counteracted the promotion of circRSF1 on cell growth, migration and tube formation in ox-LDL-induced HAECs; so did CCND2 deletion on effect of miR-758 silence. Notably, circRSF1 and CCND2 could competitively bound to miR-758, and circRSF1 positively regulated CCND2 expression via miR-758. CircRSF1 could protect against ox-LDL-induced endothelial cell injury in vitro via miR-758/CCND2 axis, suggesting circRSF1 as a potential target for the treatment of atherosclerosis.