HIF-1α/HO-1 Axis Promotes Ferroptosis and Impairs Periodontal Tissue Repair in Periodontitis

To investigate whether the hypoxia-inducible factor-1alpha (HIF-1α)/heme oxygenase-1 (HO-1) axis mediates ferroptosis in periodontal ligament tissues and contributes to impaired periodontal tissue repair in periodontitis.

RNA sequencing was performed to identify ferroptosis-related pathways in ligature-induced periodontitis (LIP) model. In vivo, LIP and ligature-removal recovery models were treated with the ferroptosis inhibitor Ferrostatin-1 (Fer-1). Alveolar bone changes were assessed by micro-computed tomography. Osteoclast activity and periodontal ligament-associated repair were evaluated by TRAP staining and Periostin immunohistochemistry. Ferroptosis-related alterations were assessed by immunohistochemistry of HIF-1α, HO-1, GPX4, SLC7A11, 4-HNE and Perls staining. In vitro, an HIF-1α-activated hPDLSC model was established. Ferroptosis-related changes were evaluated by ROS, MDA, Fe²⁺ levels, C11-BODIPY staining and expression of ferroptosis-associated molecules. The HIF-1α/HO-1 regulatory relationship was examined by ChIP-qPCR and dual-luciferase reporter assays.

RNA sequencing revealed enrichment of ferroptosis-related pathways and identified HIF-1α and HO-1 as central regulators in inflamed periodontal ligament tissues. In vivo, Fer-1 attenuated alveolar bone loss, osteoclast activity and inflammatory cell infiltration. These changes were accompanied by decreased HO-1 expression, iron deposition and 4-HNE levels, along with increased GPX4 and SLC7A11 expression. In the recovery model, Fer-1 further reduced oxidative stress, suppressed osteoclast activity and increased Periostin expression, indicating improved periodontal tissue repair. In vitro, HIF-1α activation was associated with increased Fe²⁺ accumulation, ROS production and ferroptosis-related molecular alterations. Mechanistically, HIF-1α directly transactivated HO-1, which contributed to iron accumulation and downstream ferroptosis-associated changes.

The HIF-1α/HO-1 signalling axis is associated with ferroptosis-related alterations in the PDL, which constitute periodontal tissue damage and impaired repair in periodontitis.