Hsa_circ_0030042 Ameliorates Oxidized Low-Density Lipoprotein-Induced Endothelial Cell Injury via the MiR-616-3p/RFX7 Axis

Atherosclerosis (AS) is a common etiology of cardiovascular disease. As an emerging functional biomarker, circular RNAs (circRNAs) are involved in various diseases, including cardiovascular disease. However, the mechanism of action of circ_0030042 in AS has not been reported. Human umbilical vein endothelial cells (HUVECs) stimulated by ox-LDL served as a cellular model of AS. Gene expression was detected using quantitative real-time polymerase chain reaction. The influence of circ_ 0030042 on cell viability, proliferation, and apoptosis was verified using Cell Counting Kit-8, 5-ethynyl-2'deoxyuridine, and flow cytometry assays. An enzyme-linked immunosorbent assay was performed to measure the contents of tumor necrosis factor-alpha, interleukin (IL)-6, and IL-1 beta. Western blot assay was utilized to determine the protein levels of Bax, Bcl-2, PCNA, and regulatory factor X 7 (RFX7). The interrelationship between miR-616-3p and circ_0030042 or RFX7 was validated using dual-luciferase reporter, RNA immunoprecipitation, and RNA pull-down assays. The expression of circ_0030042 was downregulated in ox-LDL-induced HUVECs. It was found that overexpression of circ_0030042 facilitated cell proliferation, repressed apoptosis, and reduced the level of inflammatory factors in HUVECs. Circ_0030042 and miR-616-3p had a targeting relationship, and the miR-616-3p mimic eliminated the effects of overexpressed circ_0030042 on ox-LDL-induced HUVECs. RFX7 was a downstream gene of miR-616-3p and was lowly expressed in ox-LDL-induced HUVECs. The miR-616-3p inhibitor stimulated cell proliferation, arrested apoptosis, and caused a decline in the levels of inflammatory factors, whereas knockdown of RFX7 abolished the effects. Circ_0030042 weakened ox-LDL-induced HUVEC injury by regulating the miR-616-3p/RFX7 pathway, thereby influencing AS progression. Circ_0030042 is likely to be a potential biomarker for the future treatment of patients with AS.