AIMS

Circular RNA (circRNA) is involved in the regulation of articular cartilage degeneration induced by inflammatory factors or oxidative stress. In a previous study, we found that the expression of was significantly reduced in chondrocytes of osteoarthritis (OA) patients and OA mice. Therefore, the aim of this paper was to explore the role and mechanism of in osteoarthritis.

METHODS

Minus RNA sequencing, fluorescence in situ hybridization, and quantitative real-time polymerase chain reaction (qRT-PCR) were used to detect the expression of in human and mouse OA cartilage tissues and chondrocytes. Chondrocytes were then stimulated to secrete exosomal miR-9-5p by cyclic tensile strain. Intra-articular injection of exosomal miR-9-5p into the model induced by destabilized medial meniscus (DMM) surgery was conducted to alleviate OA progression.

RESULTS

Tensile strain could decrease the expression of in chondrocytes. expression was significantly decreased in human and mouse OA cartilage tissues and chondrocytes. could inhibit matrix metabolism of chondrocytes through competitively 'sponging' miRNA-9-5p targeting Kruppel-like factor 5 (), indicating that the decrease in might be a protective factor in mechanical instability-induced OA. The tensile strain stimulated chondrocytes to secrete exosomal miR-9-5p. Exosomes with high expression from chondrocytes could inhibit osteoblast differentiation by targeting . Intra-articular injection of exosomal alleviated the progression of OA induced by destabilized medial meniscus surgery in mice.

CONCLUSION

Taken together, these results demonstrate that reduction of causes an increase in , which acts as a protective factor in mechanical instability-induced OA, and provides a novel mechanism of communication among joint components and a potential application for the treatment of OA.Cite this article:  2023;12(1):33-45.