11β-Hydroxysteroid dehydrogenase 1 inhibition attenuates collagen-induced arthritis.

11β-Hydroxysteroid dehydrogenase 1 (11β-HSD1) plays an important role in inflammation. However, the role of 11β-HSD1 in rheumatoid arthritis (RA) remains unknown. The purpose of this study was to evaluate the therapeutic effects of a selective 11β-HSD1 inhibitor BVT-2733 in collagen-induced arthritis (CIA) and its underlying mechanisms. CIA mice were treated with BVT-2733 (100 mg/kg, orally) or vehicle twice daily for 2 weeks. Arthritis score and joint histology were investigated. The levels of pro-inflammatory cytokines as well as anti-type II collagen antibody (anti-CII) were detected by ELISA. Western blot analysis was used to assess the activation of NF-κB and NLRP1 inflammasome in joint tissues and in human RA synovial cells. BVT-2733 treatment attenuated the arthritis severity and anti-CII level in CIA mice. BVT-2733 also decreased the levels of serum TNF-α, IL-1β, IL-6 and IL-17. BVT-2733 treatment also significantly reduced synovial inflammation and joint destruction. NF-κB activation and NLRP1 inflammasome assembly were also inhibited in arthritic joints and human RA synovial cells. In conclusion, BVT-2733 exhibits an anti-inflammatory effect on CIA. This protective effect is, at least partly, mediated by inhibition of the NF-κB and NLRP1 inflammasome signaling pathways. 11β-HSD1 inhibition may represent a potential therapeutic target for RA patients.