Ferroptosis inhibits cementoblast mineralization via cGAS-STING/GPX4 axis

To explore the potential role of cGAS-STING/GPX4 axis-mediated ferroptosis in cementoblast mineralization under compressive force and to determine its involvement in orthodontically induced inflammatory external root resorption (OIIERR). An immortalized murine cementoblast cell line (OCCM-30) was subjected to a 2 g/cm 2 compressive force for 24 h to establish an in vitro loading model. Western blot was used to detect proteins associated with mineralization (RUNX2, OPN, OCN) and components of the cGAS-STING/GPX4 axis. Ferroptosis was assessed by measuring ROS, Fe 2+ , and MDA levels. Mitochondrial damage was examined via mitochondrial membrane potential analysis and mtDNA linkage evaluation. To further investigate the role of cGAS-STING/GPX4 axis-mediated ferroptosis, STING knockdown and Ferrostatin-1 (Fer-1) were employed. In vivo, an OIIERR mouse model was established, and the STING inhibitor H-151 was administered to assess the involvement of cGAS-STING/GPX4 axis-mediated ferroptosis in OIIERR. Compressive force significantly reduced RUNX2, OPN, OCN, and GPX4 expression, while increasing ROS, Fe 2+ , and MDA levels. Mitochondrial dysfunction, including decreased membrane potential and cytoplasmic mtDNA leakage, was observed. Western blot analysis showed that compressive force significantly upregulated cGAS, p-STING, p-TBK1 and p-IRF3 in OCCM-30 cells. Knockdown of STING or Fer-1 treatment restored mineralization under compressive force. In vivo, immunohistochemical staining confirmed the activation of cGAS-STING/GPX4 axis in the OIIERR group. Notably, administration of H-151 reduced the expression of pathway-related proteins and effectively mitigated root resorption. Compressive force inhibits cementoblast mineralization by inducing ferroptosis via the cGAS-STING/GPX4 axis. Furthermore, H-151 effectively suppresses OIIERR in mice. Targeting cGAS-STING/GPX4 axis-mediated ferroptosis may serve as a potential therapeutic strategy for OIIERR treatment.