Knockdown of hsa_circ_0134111 alleviates the symptom of osteoarthritis via sponging microRNA-224-5p.

The relevance of circular RNAs (circRNAs) has been indicated in the progression of various diseases. Nevertheless, the precise function of circRNAs in osteoarthritis (OA) remains to be established. Therefore, we aimed to investigate changes in the expression of a specific circRNA, hsa_circ_0134111 (circ_PDE1C) and predict its functions in OA. A rat model of OA was constructed to detect circ_PDE1C expression in knee joint tissues. Subsequently, CHON-001 chondrocytes were treated with IL-1β to mimic OA in vitro. circ_PDE1C was significantly overexpressed in knee cartilage tissues from OA patients relative to amputation patients. Knockdown of circ_PDE1C inhibited extracellular matrix (ECM) degradation and chondrocyte apoptosis. Furthermore, circ_PDE1C could target miR-224-5p, and miR-224-5p expressed poorly in knee cartilage tissues from OA patients. Overexpression of miR-224-5p inhibited ECM degradation and apoptosis in chondrocytes. miR-224-5p also targeted CCL2, which activated the JAK2/STAT signaling pathway, thereby promoting cartilage degradation and exacerbating the symptoms of OA patients. In conclusion, our findings underscore a novel role of circ_PDE1C in OA pathogenesis and suggest that targeting circ_PDE1C/miR-224-5p/CCL2 axis might provide an attractive approach for OA therapy.