Circ_0020014 mediates CTSB expression and participates in IL-1β-prompted chondrocyte injury via interacting with miR-24-3p.

backgroundRecent studies have shown that circRNAs are involved in the pathogenesis of osteoarthritis (OA) by affecting various fundamental cellular characteristics of chondrocytes. The purpose of this paper is to investigate the role and regulatory mechanism of hsa_circ_0020014 (circ_0020014) in chondrocytes of OA.

methodsThe inflammatory cytokine interleukin 1 beta (IL-1β) was used to stimulate human chondrocytes. Cell viability, proliferation, and apoptosis were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), 5-Ethynyl-2'-deoxyuridine (EdU), and flow cytometry assays. Several protein levels were determined by western blotting (WB). Levels of inflammatory cytokines and malondialdehyde (MDA) were determined by enzyme-linked immunosorbent assay (ELISA). Relative expression of circ_0020014 was estimated by real-time polymerase quantitative chain reaction (RT-qPCR). Bioinformatics prediction combined with dual-luciferase reporter, RIP and RNA pull-down assays were done to probe into the regulatory mechanism of circ_0020014.

resultsCirc_0020014 was overexpressed in OA patient-derived articular cartilages and IL-1β-stimulated chondrocytes. Silencing of circ_0020014 lighted IL-1β-prompted chondrocyte proliferation repression, apoptosis, inflammation, and oxidative stress. Mechanically, circ_0020014 functioned as a miR-24-3p molecular sponge to regulate cathepsin B (CTSB) expression. Furthermore, miR-24-3p inhibition alleviated circ_0020014 knockdown-mediation repression of IL-1β-urged chondrocyte injury. In addition, CTSB overexpression whittled miR-24-3p upregulation-mediated suppression of IL-1β-urged chondrocyte injury.

conclusionOur findings demonstrated that the circ_0020014/miR-24-3p/CTSB axis was associated with IL-1β-prompted chondrocyte injury, supporting the involvement of circ_0020014 in the OA pathogenesis.