Circular RNA_0003800 exacerbates IL-1ß-induced chondrocyte injury via miR-197-3p/SOX5 axis.

BACKGROUND: Osteoarthritis (OA) is a serious degenerative disease of articular cartilage, which has a great impact on the quality of life of patients. Circular RNA (circRNA) plays an important role in OA progression. Our study aims to explore the role and mechanism of circ_0003800 in OA. METHODS: Circ_0003800, microRNA-197-3p (miR-197-3p) and SRY-box transcription factor 5 (SOX5) contents were measured by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot. Cell Counting Kit-8 (CCK8), 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, western blot and enzyme-linked immunosorbent assay (ELISA) were deployed to evaluate cell proliferation, apoptosis, extracellular matrix (ECM) degradation, inflammatory response and oxidative stress. Interaction of miR-197-3p and circ_0003800 or SOX5 was evidenced by dual-luciferase reporter system, RNA immunoprecipitation (RIP) and RNA pull down assays. RESULTS: OA tissues and model cells had higher abundance of circ_0003800 and SOX5, while miR-197-3p content was lower. Functionally, circ_0003800 knockdown alleviated IL-1ß-mediated injury in C28/I2 cells. Mechanistically, circ_0003800 could sponge miR-197-3p, and miR-197-3p could target SOX5. Besides, in-miR-197-3p reversed the suppressive effect of circ_0003800 downregulation on IL-1ß-induced C28/I2 cell injury, and SOX5 overexpression could also diminish the inhibitory effect of miR-197-3p on IL-1ß-induced C28/I2 cell injury. CONCLUSION: Circ_0003800 exacerbates IL-1ß-induced chondrocyte injury via miR-197-3p/SOX5 axis.