Circ_0124644 enhances ox-LDL-induced cell damages in human umbilical vein endothelial cells through upregulating FOXO4 by sponging miR-370-3p

Abstract

Circular RNA circ_0124644 has crucial regulation in the progression of coronary artery diseases, including atherosclerosis (AS). The aim of this study was to explore the regulatory mechanism of circ_0124644 in oxidized low-density lipoprotein (ox-LDL)-induced endothelial injury in human umbilical vein endothelial cells (HUVECs). Cell viability and proliferation were assessed using cell counting kit-8 (CCK-8) assay and EdU assay. The apoptosis detection was performed by flow cytometry. Angiogenesis was evaluated through tube formation assay. The protein analysis was conducted via western blot. Inflammatory cytokines were examined by enzyme-linked immunosorbent assay (ELISA). The expression determination of circ_0124644, microRNA-370-3p (miR-370-3p) and forkhead box protein O4 (FOXO4) was performed through reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were used to analyze the interaction between targets. Treatment of ox-LDL resulted in the inhibition of cell viability, proliferation and angiogenesis but the promotion of apoptosis and inflammation in HUVECs. These ox-LDL-induced cell damages were alleviated after the downregulation of circ_0124644. Circ_0124644 interacted with miR-370-3p, and the regulatory role of circ_0124644 was associated with the sponge function of miR-370-3p. Additionally, miR-370-3p targeted FOXO4 and circ_0124644 increased the expression of FOXO4 through acting as a sponge of miR-370-3p. Overexpression of miR-370-3p protected from ox-LDL-induced injury via the downregulation of FOXO4. All results revealed that circ_0124644 accelerated endothelial injury in ox-LDL-treated HUVECs by mediating miR-370-3p-related FOXO4 expression.