The E3 Ubiquitin Ligase RNF31 Mediates the Development of Ulcerative Colitis by Regulating NLRP3 Inflammasome Activation.

Ulcerative colitis (UC) is characterized by dysregulated inflammation and disruption of the intestinal barrier. The NLRP3 inflammasome, which is composed of NLRP3, ASC, and caspase-1, plays a crucial role in UC pathogenesis by triggering the production of proinflammatory cytokines. In this study, we investigated the regulatory role of RNF31 in NLRP3 inflammasome activation during UC development. Through comprehensive analysis of ulcer-ative colitis tissues using the GEO database and immunohistochemistry, we found that RNF31 expression was elevated in UC tissues, which prompted further investigation into its function. We constructed an RNF31 knockdown cell model and observed a significant reduction in NLRP3 inflammasome activation, indicating the involvement of RNF31 in regulating NLRP3. Mechanistically, RNF31 could interact with NLRP3 through the RBR structural domain, leading to increased K63-linked ubiquitination of NLRP3 and consequent stabilization. Coimmunoprecipitation experiments revealed a mutual interaction between RNF31 and NLRP3, substantiating their functional association. Finally, an in vivo mouse model with RNF31 knockdown showed a notable reduction in NLRP3 expression, which was accompanied by a decrease in the proinflammatory cytokines IL-18 and IL-18. The successful attenuation of DSS-induced tissue inflammation by this treatment confirmed the physiological relevance of RNF31-mediated regulation of NLRP3. This study unveils a novel regulatory pathway by which RNF31 affects NLRP3 inflammasome activation, providing new insights into UC pathogenesis and potential therapeutic targets for UC treatment.