CircMYO1C silencing alleviates chondrocytes inflammation and apoptosis through m6A/HMGB1 axis in osteoarthritis.

Circular RNAs (circRNAs) are involved in osteoarthritis (OA) progression. This study aimed to investigate the role and molecular mechanisms of circMYO1C in OA. CircMYO1C was upregulated in OA- and interleukin-1β (IL-1β)-exposed chondrocytes. The results indicated that circMYO1C knockdown repressed the inflammatory factors (tumor necrosis factor alpha [TNF-α], interleukin-6 [IL-6], interleukin-8 [IL-8], etc.) and apoptosis of chondrocytes following IL-1β exposure. CircMYO1C was an N⁶-methyladenosine (m⁶A)-modified circRNA with m6A characteristics. High mobility group box 1 (HMGB1) was a target of circMYO1C. IL-1β exposure increased the stability and half-life (t_1/2) of HMGB1 mRNA, while silencing circMYO1C reduced HMGB1 mRNA stability. Taken together, circMYO1C targets the m6A/HMGB1 axis to promote chondrocyte apoptosis and inflammation. The present study demonstrates that the circMYO1C/m6A/HMGB1 axis is essential for OA progression, highlighting a novel potential therapeutic target for clinical OA.