hsa_circ_0058122 knockdown prevents steroid-induced osteonecrosis of the femoral head by inhibiting human umbilical vein endothelial cells apoptosis via the miR-7974/IGFBP5 axis

Background Steroid-induced osteonecrosis of femoral head (SONFH) is a serious complication of glucocorticoid overused. Recent evidence has demonstrated that circRNAs exert key pathophysiological roles in a variety of disease processes. However, the role of circRNA in SONFH remains largely unknown. The current study sought to evaluate how hsa_circ_0058122 affects SONFH in dexamethasone (DEX) treated human umbilical vein endothelial cells (HUVECs) model. Methods RT-PCR was used to demonstrate the hsa_circ_0058122 expression level in Dex-treated HUVECs cells. The effects of hsa_circ_0058122 on HUVECs apoptosis were evaluated via overexpression plasmid and siRNA. Using dual-luciferase and fluorescence in situ hybridization assays, we demonstrated that hsa_circ_0058122 binds to miR-7974 thereby facilitating HUVECs apoptosis. Bioinformatics analysis and western blot were performed to confirm target genes of hsa-miR-7974. Results In our previous work, we revealed the top 20 elevated circRNAs in SONFH patients were hsa_circ_0010027, hsa_circ_0058115, hsa_circ_0010026, hsa_circ_0058839, hsa_circ_0056886, hsa_circ_0056885, hsa_circ_0058146, hsa_circ_0058105, hsa_circ_0058112, hsa_circ_0058143, hsa_circ_0058102, hsa_circ_0058090, hsa_circ_0075353, hsa_circ_0058126, hsa_circ_0058130, hsa_circ_0058140, hsa_circ_0058122, hsa_circ_0058123, hsa_circ_0058103, and hsa_circ_0058121. Among these, hsa_circ_0058122 was finally selected for further investigation. We found hsa_circ_0058122 expression was markedly elevated in Dex-treated HUVECs cells, and the Dex-mediated HUVEC apoptosis was impaired in hsa_circ_0058122-silenced cells and increased in hsa_circ_0058122-overexpressing cells. hsa_circ_0058122 competitively binds to hsa-miR-7974, which in turn interacts with insulin-like growth factor binding protein 5 (IGFBP5). Conclusions hsa_circ_0058122/miR-7974/IGFBP5 was proposed to be a key regulatory pathway for SONFH. DEX treatment upregulated hsa_circ_0058122 expression in HUVECs, which sponged miR-7974, thereby increasing IGFBP5 expression, the hsa_circ_0058122/miR-7974/IGFBP5 axis contributed to the Dex-mediated apoptosis. These findings may identify novel targets for SONFH molecular therapy.