Targeting the PXR-TLR4 signaling pathway to reduce intestinal inflammation in an experimental model of necrotizing enterocolitis

BACKGROUND: There is substantial evidence that signaling through Toll-like receptor 4 (TLR4) contributes to the pathogenesis of necrotizing enterocolitis (NEC). Pregnane X receptor (PXR), a xenobiotic sensor and signaling intermediate for certain host-bacterial metabolites, has been shown to negatively regulate TLR4 signaling Here we investigated the relationship between PXR and TLR4 in the developing murine intestine and explored the capacity of PXR to modulate inflammatoty pathways involved in experimental NEC. METHODS: Wild type and PXR-/- mice were studied at various time points of development in an experimental model of NEC In addition, we studied the ability of the secondary bile acid lithocholic acid (LCA), a known PXR agonist in liver, to activate intestinal PXR and reduce NEC related intestinal inflammation. RESULTS: We found a reciprocal relationship between the developmental expression of PXR and TLR4 in wild type murine intestine, with PXR acting to reduce TLR4 expression by decreasing TLR4 mRNA stability in addition, PXR(-/- )mice exhibited a remarkably heightened seventy of disease in experimental NEC Moreover, LCA attenuated intestinal proinflammatory responses in the early stages of experimental NEC. CONCLUSION: These findings piovide proactive insights into the regulation of TLR4 in the developing intestine Targeting PXR may be a novel approach for NEC prevention.