Erianin protects chondrocytes against IL-1β-induced oxidative stress and ferroptosis by activating GPX4/STING signaling in osteoarthritis.

BACKGROUND: Erianin (Eri) has been known for its analgesic and antipyretic properties. This research focuses on impact of Eri on chondrocyte viability, inflammatory cytokine production, extracellular matrix (ECM) degradation, and ferroptosis, which are key factors in cartilage diseases. METHODS: The mouse model of osteoarthritis (OA) was induced by destabilization of medial meniscus (DMM). Chondrocytes were treated with different concentrations of Eri and exposed to IL-1β to simulate disease conditions. The chondrocytes were induced to undergo ferroptosis using erastin (Era), and ferroptosis was inhibited by Fer-1. This was done to form an intervention control group in combination with Era and to explore the synergistic effect. The effects of Eri on cell viability, proliferation, inflammatory responses, ECM degradation, and ferroptosis were assessed using CCK-8 analysis, EDU assay, Western blot, immunofluorescence, ROS staining, and flow cytometry. The Cellular Thermal Shift Assay (CETSA) was also employed to confirm the direct binding and thermal stability of GPX4 and STING in the presence of Eri. RESULTS: The findings indicate that Eri does not exhibit cytotoxic effects at certain concentrations and can actually enhance chondrocyte proliferation and viability. It also reduces the production of inflammatory cytokines and ECM degradation products, suggesting a protective role against cartilage damage. Furthermore, Eri was found to inhibit ferroptosis in chondrocytes, potentially through the activation of the GPX4/STING signaling pathway. Molecular docking combined with CETSA confirmed that Eri enhances the thermal stability of GPX4 and STING, indicating a stabilizing effect on this key enzyme. In the DMM mouse model, Eri significantly alleviated cartilage degeneration and improved chondrocyte function, as evidenced by reduced osteophyte formation and subchondral bone sclerosis. Eri can act independently or in combination with the ferroptosis inducer erastin (Era) and the ferroptosis inhibitor Ferrostatin-1 (Fer-1). By inhibiting lipid peroxidation, regulating cell proliferation and extracellular matrix degradation, it exerts an intervention effect on IL-1β-induced ferroptosis of chondrocytes. Moreover, when used in combination with Fer-1, it has a synergistic enhancing effect in reversing ferroptosis-related damage. CONCLUSIONS: Eri demonstrates promising therapeutic potential in the treatment of OA by inhibiting chondrocyte ferroptosis and protecting against ECM degradation and inflammatory responses.