Huaier aqueous extract protects against dextran sulfate sodium-induced experimental colitis in mice by inhibiting NLRP3 inflammasome activation

The use of Trametes robiniophila Murr. (Huaier) as a complementary therapy for cancer has recently become increasingly common in China. However, whether Huaier can regulate host immune responses, especially innate immunity, remains largely unknown. The NLRP3 inflammasome is a multimeric complex consisting of NLRP3, ASC and caspase-1. NLRP3 inflammasomes respond to a variety of endogenous (damage-associated molecular patterns) and exogenous (pathogen-associated molecular patterns) stimuli, and play crucial roles in host defense against pathogens and multiple diseases such as ulcerative colitis (UC). In this study, we investigated the anti-inflammatory effect of Huaier in dextran sulfate sodium (DSS)-induced murine colitis and revealed the underlying mechanisms by targeting NLRP3 inflammasomes. In C57BL/6 mice, oral administration of Huaier attenuated DSS-induced colon shortening and colonic pathological damage. Furthermore, we analyzed the effect of Huaier on NLRP3 inflammasome activation in macrophages. Huaier inhibited NLRP3 inflammasome activation-induced IL-1β secretion and caspase-1 cleavage. Moreover, Huaier decreased NLRP3 protein expression via promoting NLRP3 degradation through the autophagy lysosome pathway. Therefore, our findings demonstrate a novel function for Huaier in the regulation of NLRP3 inflammasome activation and suggest a potential role for Huaier in NLRP3 inflammasome-associated diseases.