Abnormal mechanical stress induced chondrocyte senescence by YAP loss-mediated METTL3 upregulation

OBJECTIVES: Abnormal mechanical stress is the pivotal risk factor of temporomandibular joint osteoarthritis (TMJOA). This study investigated the pathogenic mechanism by which abnormal mechanical stress induced chondrocyte senescence. MATERIALS AND METHODS: Cellular senescence was investigated in the rodent model of unilateral anterior crossbite and in the chondrocytes subjected to mechanical overloading in vitro. The effects of Yes-associated protein (YAP) in chondrocyte senescence and its correlation with methyltransferase-like 3 (METTL3) and N⁶-methyladenosine (m⁶A) modification were evaluated. The role of m⁶A modification in chondrocyte senescence was determined. The therapeutic effects of m⁶A inhibition in TMJOA were investigated. RESULTS: Senescent chondrocytes were accumulated in the mechanically induced TMJOA lesions in rats and mechanical overloading could trigger chondrocyte senescence in vitro. This mechanical stress-induced cellular senescence was revealed to be mediated by YAP deficiency that promoted METTL3-dependent m⁶A modification. Moreover, inhibition of m⁶A modification rescued chondrocyte senescence in vitro and in vivo, and suppressed TMJOA progression in rats. CONCLUSIONS: This study uncovered the underlying mechanism of mechanically induced senescence in TMJOA from the perspective of epitranscriptomics and revealed the therapeutic potential of m⁶A inhibition in TMJOA.