Molecular Mechanisms of Cuproptosis in Osteoarthritis: Pathways, Crosstalk, and Therapeutic Opportunities.

Osteoarthritis (OA), the most prevalent degenerative joint disorder worldwide, continues to impose significant personal and societal burdens due to the absence of effective disease-modifying therapies. Recent advances in metallobiology have identified cuproptosis, a copper (Cu)-dependent regulated cell death pathway, as a potential driver of OA pathogenesis. In OA, dysregulated Cu homeostasis has been linked to oxidative stress, inflammatory signalling activation, mitochondrial dysfunction, and direct chondrocyte injury. Mechanistically, Cu²⁺ overload promotes aggregation of lipoylated tricarboxylic acid (TCA) cycle enzymes and destabilisation of iron-sulfur clusters, thereby impairing mitochondrial integrity and cellular metabolism. Emerging evidence also highlights extensive crosstalk between cuproptosis and ferroptosis, mediated largely by glutathione depletion and glutathione peroxidase 4 (GPX4) dysfunction, which amplifies oxidative damage in joint tissues. This review synthesises current evidence on Cu metabolism, the regulation and function of cuproptosis-related genes (CRGs), and their roles in immune infiltration, inflammatory signalling, and cartilage degeneration in OA. We further examine the interplay between cuproptosis and ferroptosis, and critically evaluate therapeutic strategies, including Cu chelation, antioxidant reinforcement, and pathway modulation, that may offer disease-modifying potential. By integrating these mechanistic insights, we aim to define new translational opportunities for OA management and outline priority areas for future research.