Trem1-Cgas-Sting Axis-Induced Ferroptosis Accelerates Pulpitis

To address the limitations of conventional root canal therapy for pulpitis, this study investigates the mechanism by which LPS-induced damage to dental pulp stem cells (DPSCs) promotes pulpitis progression through TREM1-mediated mitochondrial fission. DPSCs were isolated from healthy human dental pulp and characterized by flow cytometry for mesenchymal (CD44⁺, CD73⁺, CD90⁺, CD105⁺) and hematopoietic (CD34⁻, CD45⁻) markers. In vitro models were established using LPS for 7 days under osteogenic differentiation conditions. Cell viability was measured via CCK8 assay, while odontoblastic differentiation was evaluated by ALP/ARS staining and Western blot analysis of DSPP/DMP1. Ferroptosis markers included ROS (MitoSOX), MDA (thiobarbituric acid assay), GPX4/Slc7a11 expression (Western blot/qPCR), GSH content (colorimetric assay), and iron accumulation (ICP-MS). Transmission electron microscopy visualized mitochondrial morphological changes. In vivo, C57BL/6 mice underwent pulp exposure to induce inflammation, with TREM1 knockdown using AAV8-mediated delivery. Mandibles were analyzed by HE/Masson staining for inflammation/fibrosis, Micro-CT for dentin thickness, and immunohistochemistry for TREM1/DRP1 expression. DPSCs activity was evaluated by immunofluorescence for DSPP/DMP1 and stem cell markers. LPS upregulates TREM1/DRP1 expression, activates cGAS-STING, and induces ferroptosis in DPSCs, thereby inhibiting odontoblastic differentiation. TREM1/DRP1 knockdown reverses these effects both in vitro and in vivo, reducing inflammation and promoting pulp repair. The TREM1-cGAS-STING axis drives ferroptosis-mediated DPSCs dysfunction in pulpitis, offering a novel therapeutic target for inflammatory dental diseases.