Dual inhibition of TNF-α and IL-1β signaling through BIG2 ameliorates osteoarthritis in mouse and primate models.

Abstract

Osteoarthritis (OA), a leading cause of disability, is characterized by chronic low-grade inflammation and metabolic dysregulation in chondrocytes. TNF-α and IL-1β are key inflammatory drivers in OA pathogenesis, but clinical trials targeting them individually have been unsuccessful, highlighting the potential need for dual-targeting strategies. By screening a US Food and Drug Administration-approved drug library, we identified dabigatran, a thrombin inhibitor, as a potent dual suppressor of TNF-α and IL-1β signaling that restored chondrocyte metabolism. In preclinical OA models, including both mice and cynomolgus macaques, dabigatran attenuated cartilage degeneration, alleviated pain, and improved joint function. To elucidate the molecular mechanisms, we performed biochemical copurification coupled with mass spectrometry, identifying brefeldin A-inhibited guanine nucleotide-exchange protein 2 (BIG2) as a previously unknown dabigatran-binding target. Mechanistically, dabigatran binds to BIG2, promoting BIG2-dependent TNFR1 release to dampen TNF-α signaling while enhancing BIG2-mediated IL-1R1 degradation through the autophagy-lysosome pathway to limit IL-1β effects. These findings establish BIG2-mediated receptor trafficking and membrane dynamics as a regulatory node that concurrently inhibits TNF-α and IL-1β signaling, suggesting this pathway as a potential therapeutic strategy for OA.

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