Circular RNA CSNK1G1 promotes the progression of osteoarthritis by targeting the miR‑4428/FUT2 axis.

Osteoarthritis (OA) is a chronic disease that results in chronic arthralgia and functional disability of the affected joint. To date, there is no effective treatment available for this disease. Circular RNAs (circRNAs) are a type of intracellular stable RNA that can regulate the development and progression of OA. However, the function of circCSNK1G1 in OA has not yet been investigated. In the present study, it was found that circCSNK1G1 was upregulated in OA cartilage tissues. The upregulation of circCSNK1G1 was associated with extracellular matrix (ECM) degradation and chondrocyte apoptosis. Moreover, the expression of miR‑4428 was downregulated and that of fucosyltransferase 2 (FUT2) was upregulated in OA‑affected cartilage tissues. Dual‑luciferase reporter assay and RNA immunoprecipitation confirmed that miR‑4428 targeted FUT2 mRNA to inhibit FUT2 expression. circCSNK1G1 and FUT2 induced ECM degradation and chondrocyte apoptosis. The negative effects of circCSNK1G1 and FUT2 were reversed by miR‑4428. On the whole, the present study demonstrates that circCSNK1G1 promotes the development of OA by targeting the miR‑4428/FUT2 axis. Thus, the circCSNK1G1/miR‑4428/FUT2 axis may present a novel target for the treatment of OA in the clinical setting.