Investigating the impact and mechanism of Licochalcone B derivative CTG12 on NLRP3 inflammasome

Aberrant activation of NLRP3 inflammasome has been associated with a variety of human inflammatory diseases, but no small molecule inhibitors of NLRP3 were applied in clinical practice. Our research group has previously shown that licochalcone B is an effective NLRP3 inflammasome inhibitor, however, its IC50 value is relatively high compared to compounds such as MCC950. Modifying bioactive natural products to find NLRP3 inflammasome inhibitors with stronger potency and higher specificity is a direction worthy of investigation. Our research aims to evaluate the impact of various licochalcone B derivatives on NLRP3 inflammasome, to screen for derivatives with better potency and elucidate the underlying mechanisms. We investigated the effects of licochalcone B and its derivatives on NLRP3 inflammasome by assessing the production of active caspase-1 and interleukin 1β (IL-1β). To elucidate the mechanism of CTG12, we employed co-immunoprecipitation. Furthermore, we evaluated CTG12 in LPS-induced acute systemic inflammation mouse models. The findings demonstrated that licochalcone B and its derivatives effectively inhibit NLRP3 inflammasome. CTG12 exhibits the most potent inhibitory activity, showing approximately tenfold increased effects compared to licochalcone B. Mechanistic investigations reveal that while CTG12 does not affect potassium (K⁺) efflux, calcium (Ca2⁺) influx, or mitochondrial reactive oxygen species (mtROS) production, it suppressed NLRP3 assembly by interfering with the ASC-NLRP3 interaction and the NLRP3-dependent ASC oligomerization process. In vivo, CTG12 provides significant therapeutic benefits in LPS-induced acute systemic inflammation models. Our results indicated that structurally modified licochalcone B derivative CTG12 inhibits NLRP3 assembly by interfering with the ASC-NLRP3 interaction, thereby inhibiting the NLRP3-dependent ASC oligomerization process in NLRP3 inflammasome activation. These studies would show that CTG12 is a valuable small molecule inhibitor that holds promise as a high-value drug candidate for the treatment of NLRP3-mediated inflammatory diseases.