Lappaconitine hydrobromide prevents NLRP3-GSDMD-mediated pyroptosis to alleviate sepsis-induced acute lung injury by enhancing NR1H3.

Evidence indicates that nuclear receptor subfamily 1 group H member 3 (NR1H3) activation mitigates sepsis-induced acute lung injury (SALI) by reducing inflammatory response. Nevertheless, the mechanisms underlying NR1H3-inflammation interactions in addressing SALI remain unclear. Moreover, limited phytochemicals have been documented to ameliorate SALI via this pathway. Here, we discovered that NR1H3 activation directly suppresses the clustering of toll-like receptor 4 (TLR4) to lipid rafts, which acts as a part of the priming of NLR family pyrin domain containing 3 (NLRP3) inflammasome. This process results in the suppression of NLRP3 inflammasome assembly and activation, consequently alleviating gasdermin-D (GSDMD)-mediated pyroptosis. Furthermore, through dual-luciferase reporter gene testing, drug binding assays, gene expression analysis, and biochemical evaluation, we determined lappaconitine hydrobromide (LAH) as a novel NR1H3 agonist that effectively suppresses TLR4-NLRP3 signaling pathway. Our results showed LAH attenuates inflammatory lung injury in both lipopolysaccharide (LPS) and cecal slurry (CS)-induced SALI mouse models. In vivo and in vitro experiments revealed that LAH suppresses NLRP3 signaling activation and pyroptosis. Additionally, RNA sequencing (RNA-seq) and bioinformatics analysis demonstrated that the differentially expressed genes (DEGs) linked to interleukin-1 beta (IL-1β) production, modulation of inflammatory response, and control of innate immune response were markedly enriched in LAH, and core genes amongst the DEGs included NR1H3. Mechanistically, LAH reduces inflammation and pyroptosis through modulation of NR1H3-NLRP3-GSDMD axis in mice. This finding was further substantiated by the suppression of NR1H3 in vitro. Our findings offer novel perspectives on the NR1H3-inflammation interaction in SALI regulation and indicate the therapeutic promise of LAH as an NR1H3 agonist for SALI management via NLRP3 suppression.