The protective role of Nesfatin-1 against TNF-α-induced ferroptosis in chondrocytes: Implications for osteoarthritis therapy.

Osteoarthritis (OA) progression is significantly driven by chondrocyte ferroptosis, a form of iron-dependent cell death triggered by oxidative stress and lipid peroxidation. This study investigated the protective effect of Nesfatin-1 against TNF-α-induced ferroptosis in mouse primary chondrocytes and explored the underlying mechanism. A ferroptosis model was established using TNF-α (10 ng/mL). Cell viability, cytotoxicity, and key ferroptosis markers were assessed. We found that endogenous NUCB2/nesfatin-1 is expressed in chondrocytes and downregulated by TNF-α. Nesfatin-1 treatment significantly mitigated TNF-α-induced cytotoxicity and improved cell viability. It effectively attenuated lipid peroxidation, as evidenced by reduced malondialdehyde (MDA) and reactive oxygen species (ROS) levels, and restored glutathione peroxidase (GPx) activity. Nesfatin-1 also reduced 4-hydroxynonenal (4-HNE) protein adducts, preserved SLC7A11 expression, and restored total glutathione (GSH) content. Furthermore, Nesfatin-1 reduced intracellular Fe2 + accumulation by downregulating transferrin receptor 1 (TFR1) and upregulating ferritin heavy chain (FTH). It also suppressed the ferroptosis driver ACSL4 and upregulated the key inhibitor GPx4. Crucially, Nesfatin-1 preserved the expression of extracellular matrix components, collagen II, and aggrecan, similar to the ferroptosis inhibitor Ferrostatin-1. Mechanistically, Nesfatin-1 activated the Nrf2/HO-1 signaling pathway, and its protective effects were abolished by the Nrf2 inhibitor ML385. In conclusion, Nesfatin-1 alleviates TNF-α-induced chondrocyte ferroptosis by activating the Nrf2/HO-1 pathway, suggesting its potential as a therapeutic agent for OA.