Novel inhibitory effects of dotinurad, a selective urate reabsorption inhibitor, on urate crystal-induced activation of NLRP3 inflammasomes in macrophages

Abstract

Background：When macrophages are primed by lipopolysaccharides, mono sodium urate (MSU) crystals activate NLRP3 inflammasomes and promote IL-1β and IL-18 production after phagocytosis of MSU. It was previously reported that anti-IL-1β antibodies suppress symptoms of gout and the occurrence of cardiovascular disease. Thus, inhibition of NLRP3 inflammasomes, which produce IL-1β and IL-18, may be a novel therapeutic strategy against these diseases. Purpose：To reveal the effects of dotinurad, a selective urate reabsorption inhibitor, and other uric acid lowering agents on MSU crystal-induced activation of NLRP3 inflammasomes in macrophages. Methods：Activity of NLRP3 inflammasomes in J774 mouse macrophages was evaluated by quantifying secreted caspase-1 and IL-1β using a western blot and ELISA in both the absence and presence of dotinurad or other uric acid lowering agents. Results：MSU increased protein levels of caspase-1 and IL-1β. This effect was inhibited by a clinical concentration of dotinurad. Neither febuxostat nor allopurinol influenced the levels of caspase-1 and IL-1β, whereas benzbromarone decreased their levels. The inhibitory effects of dotinurad and other uric acid lowering agents on secretions of IL-1β from the macrophages were confirmed by ELISA. Conclusion：Dotinurad, a selective urate reabsorption inhibitor, suppresses MSU-induced activation of NLRP3 inflammasomes in macrophages.