Hsa_circ_0007482 Promotes Proliferation and Differentiation of Chondrocytes in Knee Osteoarthritis.

Objective: Knee osteoarthritis (KOA) is a complex degenerative joint disease and a major cause of joint dysfunction. This study aimed to explore the function of hsa_circ_0007482 on inflammation, proliferation, differentiation, and apoptosis in KOA.

Design: Real-time quantitative polymerase chain reaction (PCR) was performed to detect the expression of circ_0007482, inflammatory factors, and differentiation-related molecules in KOA chondrocytes and interleukin (IL)-1β-stimulated chondrocytes. The correlation between the circ_0007482 expression and inflammatory factors was analyzed by the Pearson method. KOA cell model was established using IL-1β for 24 hours. The proliferation activity of chondrocytes was evaluated by CCK-8 assay, and cell apoptosis rate was assessed by flow cytometry. The downstream miRNA of circ_0007482 was validated using dual-luciferase reporter assay.

Results: The circ_0007482 expression was elevated in both KOA cartilage tissues and IL-1β-treated chondrocytes and positively correlated with inflammatory factors expression. In comparison to the control group, IL-1β treatment diminished chondrocyte proliferation abilities and increased cell apoptosis and inflammatory factors IL-6, IL-8, and tumor necrosis factor (TNF)-α mRNA expression. Inhibition of circ_0007482 partially improved IL-1β-induced inflammatory reaction. Circ_0007482 could negatively regulate the expression of miR-558.

Conclusions: Interfering of circ_0007482 might partially promote cell proliferation and differentiation, while inhibit cell apoptosis to improve joint injury by regulating miR-558 in IL-1β-treated chondrocyte cell model.