Abstract
Background: To investigate the role of interferon regulatory factor 4 (IRF4) in regulating glutathione peroxidase 4 (GPX4)-mediated ferroptosis and its implications for bone homeostasis in periodontitis. Methods: The expression of IRF4 and GPX4 in cells and periodontal tissues were measured. The levels of oxidative stress-related biomarkers and ferrous iron (Fe2+), were quantified using commercial assay kits. Dual-luciferase reporter assays and chromatin immunoprecipitation (ChIP) were performed to analyze the interactions between genes. The cell counting kit-8 (CCK-8) assay was used to analyze cell viability. Lipid ROS levels were measured using the BODIPY 581/591 C11 probe. Additionally, a periodontitis mouse model was established, followed by Immunohistochemistry (IHC) analysis and hematoxylin and eosin (HE) staining. Results: The expression of IRF4 was significantly elevated in the periodontal tissues of periodontitis patients and was involved in the regulation of bone metabolism. Silencing IRF4 inhibited lipopolysaccharide (LPS)-induced ferroptosis in periodontal ligament cells (PDLCs) and promoted the expression of osteogenesis-related proteins. Additionally, ChIP and luciferase reporter assays indicated that IRF4 inhibited GPX4 expression by targeting it. Moreover, we found that IRF4 induced ferroptosis by inhibiting GPX4. Finally, animal studies showed that knocking down IRF4 inhibited ferroptosis and promoted alveolar bone regeneration in periodontitis by upregulating GPX4. Conclusions: We elucidated the critical role of IRF4 in regulating bone homeostasis in periodontitis through GPX4-mediated ferroptosis.