GPX4-mediated bone ferroptosis under mechanical stress decreased bone formation via the YAP-TEAD signalling pathway

Fracture of the alveolar bone resorption is a common complication in orthodontic treatment, which mainly caused by extreme mechanical loading. However, the ferroptosis with orthodontic tooth movement(OTM) relationship has not been thoroughly described. We here analysed whether ferroptosis is involved in OTM-associated alveolar bone loss. Mouse osteoblasts (MC-3T3) and knockdown glutathione peroxidase 4 (GPX4) MC-3T3 were stimulated with compressive force loading and ferrostatin-1 (Fer-1, a ferroptosis inhibitor), and the changes in lipid peroxidation morphology, expression of ferroptosis-related factors and osteogenesis levels were detected. After establishing the rat experimental OTM model, the changes in ferroptosis-related factors and osteogenesis levels were reevaluated in the same manner. Ferroptosis was involved in mechanical stress regulating osteoblast remodelling, and Fer-1 and erastin affected osteoblasts under compression force loading. Fer-1 regulated ferroptosis and autophagy in MC-3T3 and promoted bone proliferation. GPX4-dependent ferroptosis stimulated the YAP (homologous oncoproteins Yes-associated protein) pathway, and GPX4 promoted ferroptosis via the YAP-TEAD (transcriptional enhanced associate domain) signal pathway under mechanical compression force. The in vivo experiment results were consistent with the in vitro experiment results. Ferroptosis transpires during the motion of orthodontic teeth, with compression force side occurring earlier than stretch side within 4 h. GPX4 plays an important role in alveolar bone loss, while Fer-1 can inhibit the compression force-side alveolar bone loss. GPX4's Hippo-YAP pathway is activated by the lack of compression force in the lateral alveolar bone.