Modulation of TNFR 1-triggered two opposing signals for inflammation and apoptosis via RIPK 1 disruption by geldanamycin in rheumatoid arthritis.

GM disrupts RIPK1 and selectively inhibits the TNFR1-triggered NF-κB activation signaling pathway, while enhancing the apoptosis signaling pathway upon TNFα stimulation, thereby redressing the balance between these two opposing signals in a human rheumatoid synovial cell line. Therapeutic targeting RIPK1 may be a novel concept which involves TNF inhibitor acting as a TNFR1-signal modulator and have great potential for a more fundamental, effective, and safer TNF inhibitor. Key Points • Geldanamycin (GM) disrupts RIPK1 and selectively inhibits the TNFR1-triggered NF-κB activation signaling pathway while enhancing the apoptosis signaling pathway upon TNFα stimulation, thereby redressing the balance between these two opposing signals in a human rheumatoid synovial cell line, MH7A. • GM showed more clinical effectiveness than a conventional biologic TNF-inhibitor, etanercept, in murine collagen-induced arthritis (CIA), and significantly attenuated synovial hyperplasia, a histopathological hallmark of RA. • Therapeutic targeting RIPK1 may be a novel concept which involves TNF inhibitor acting as a TNFR1-signal modulator and have great potential for a more fundamental, effective, and safer TNF-inhibitor.