Ferroptosis inhibits cementoblast mineralization via cGAS-STING/GPX4 axis

Background: 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).

Methodology: An immortalized murine cementoblast cell line (OCCM-30) was subjected to a 2 g/cm² 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, Fe²⁺, 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.

Results: Compressive force significantly reduced RUNX2, OPN, OCN, and GPX4 expression, while increasing ROS, Fe²⁺, 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.

Conclusions: 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.

Cementoblast; Ferroptosis; Mineralization; Mitochondrial damage; Root resorption; cGAS-STING.