Pregnane X receptor activation attenuates intestinal inflammation: The role of pyroptosis and necroptosis inhibition

Intestinal inflammation compromises epithelial barrier integrity and disrupts immunological homeostasis, escalating the risk of severe gastrointestinal disorders. The Pregnane X Receptor (PXR), a xenobiotic-sensing nuclear receptor, is critical for maintaining intestinal structural integrity and suppressing inflammation, although its mechanistic underpinnings remain poorly characterized. In this study, we explored the therapeutic potential of PCN, a PXR agonist, in mitigating intestinal inflammation using two models: enterohaemorrhagic Escherichia coli O157:H7 (EHEC)-infected mice and lipopolysaccharide (LPS)-stimulated intestinal epithelial cells. PCN administration significantly improved survival rates in EHEC-challenged mice, alleviated intestinal mucosal damage, and restored tight junction protein (ZO-1 and occludin) expression. Concurrently, PCN attenuated Paneth cell dysfunction, macrophage hyperactivation, and pro-inflammatory mediator release (e.g., TNF-α, IL-6). In vitro, PCN counteracted LPS-induced barrier disruption and inflammation by suppressing the TLR4/NF-κB/MAPK axis and downstream pyroptotic (NLRP3/caspase-1/GSDMD), and necroptotic (RIPK1/RIPK3/MLKL) signaling cascades. Interestingly, both EHEC infection and LPS stimulation impaired PCN-driven PXR activation. While PCN rescued EHEC-induced mortality, histological damage, and barrier dysfunction in wild-type mice, its protective effects were markedly diminished in PXR-knockout ( PXR −/− ) mice. Furthermore, PXR silencing in cultured cells abolished PCN-mediated inhibition of NF-κB, NLRP3 inflammasome, and necroptosis pathways. These results demonstrate that PXR activation coordinately blocks pyroptosis and necroptosis by modulating the TLR4/NF-κB/MAPK-NLRP3/caspase-1/GSDMD-RIPK1/RIPK3/MLKL axis, thereby preserving intestinal homeostasis. This dual-pathway targeting positions PXR as a promising therapeutic candidate for inflammatory bowel diseases.