TFRC Ablation Induces Insufficient Cartilage Development Through Mitochondrial p53 Translocation-Mediated Ferroptosis

The mandibular condyle cartilage serves as a principal zone for mandible growth, and any dysplasia could contribute to skeletal mandibular hypoplasia (SMH). The aim of the study was to further explore how TFRC signaling regulates condylar cartilage development. In this study, TFRC, SLC39A14, chondrogenic markers and ferroptosis-related signals were detected in the condylar cartilage of postnatal mice and Tfrc cartilage conditional knockout (Tfrc-cKO) mice at different time points through immunofluorescence, immunohistochemical staining and qPCR assays. The overexpression and knockdown of TFRC in the ATDC5 cell line were used to investigate its role in a specific biological process. Co-immunoprecipitation was used to verify protein-protein interaction in vitro. Ferroptosis inhibitor Fer1, Ac-Met-OH and DFP were used for an in vitro rescue assay. The temporomandibular joint injection of DFP was used to rescue the cartilage phenotype in vivo. Our results verified that TFRC was crucial for condylar cartilage development. TFRC ablation led to condylar cartilage thickness and condyle length alterations and induced the ferroptosis of chondrocyte by upregulating SLC39A14. Mitochondrial p53 translocation was involved in the TFRC-SLC39A14 switch by SLC39A14 ubiquitination degradation. Fer1, Ac-Met-OH and DFP inhibited ferroptosis and restored chondrogenic differentiation in vivo. The temporomandibular joint injection of DFP could rescue the cartilage phenotype. In summary, this study reveals that TFRC influences postnatal condylar cartilage development through mitochondrial p53 translocation-mediated ferroptosis, which provides insights into the etiology, pathogenesis, and therapy of mandibular hypoplasia and even systemic articular cartilage dysplasia.