title: Pregnane X Receptor Activation Attenuates Inflammation-Associated Intestinal Epithelial Barrier Dysfunction by Inhibiting Cytokine-Induced Myosin Light-Chain Kinase Expression and c-Jun N-Terminal Kinase 1/2 Activation.
abstract: The inflammatory bowel diseases (IBDs) are chronic inflammatory disorders with a complex etiology. IBD is thought to arise in genetically susceptible individuals in the context of aberrant interactions with the intestinal microbiota and other environmental risk factors. Recently, the pregnane X receptor (PXR) was identified as a sensor for microbial metabolites, whose activation can regulate the intestinal epithelial barrier. Mutations in NR1I2, the gene that encodes the PXR, have been linked to IBD, and in animal models, PXR deletion leads to barrier dysfunction. In the current study, we sought to assess the mechanism(s) through which the PXR regulates barrier function during inflammation. In Caco-2 intestinal epithelial cell monolayers, tumor necrosis factor-α/interferon-γ exposure disrupted the barrier and triggered zonula occludens-1 relocalization, increased expression of myosin light-chain kinase (MLCK), and activation of c-Jun N-terminal kinase 1/2 (JNK1/2). Activation of the PXR [rifaximin and [[3,5-Bis(1,1-dimethylethyl)-4-hydroxyphenyl]ethenylidene]bis-phosphonic acid tetraethyl ester (SR12813); 10 μM] protected the barrier, an effect that was associated with attenuated MLCK expression and JNK1/2 activation. In vivo, activation of the PXR [pregnenolone 16α-carbonitrile (PCN)] attenuated barrier disruption induced by toll-like receptor 4 activation in wild-type, but not Pxr-/-, mice. Furthermore, PCN treatment protected the barrier in the dextran-sulfate sodium model of experimental colitis, an effect that was associated with reduced expression of mucosal MLCK and phosphorylated JNK1/2. Together, our data suggest that the PXR regulates the intestinal epithelial barrier during inflammation by modulating cytokine-induced MLCK expression and JNK1/2 activation. Thus, targeting the PXR may prove beneficial for the treatment of inflammation-associated barrier disruption in the context of IBD.
authors.affiliation: Department of Physiology and Pharmacology (A.G., A.Z., S.L.E., L.A., S.A.H.), and Department of Microbiology, Immunology and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (Su.M., Sr.M.); and Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (A.J.L., T.K.H.C.).
authors.forename: Aditya
authors.initials: A
authors.lastname: Garg
authors.affiliation: Department of Physiology and Pharmacology (A.G., A.Z., S.L.E., L.A., S.A.H.), and Department of Microbiology, Immunology and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (Su.M., Sr.M.); and Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (A.J.L., T.K.H.C.).
authors.forename: Angela
authors.initials: A
authors.lastname: Zhao
authors.affiliation: Department of Physiology and Pharmacology (A.G., A.Z., S.L.E., L.A., S.A.H.), and Department of Microbiology, Immunology and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (Su.M., Sr.M.); and Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (A.J.L., T.K.H.C.).
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Erickson
authors.affiliation: Department of Physiology and Pharmacology (A.G., A.Z., S.L.E., L.A., S.A.H.), and Department of Microbiology, Immunology and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (Su.M., Sr.M.); and Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (A.J.L., T.K.H.C.).
authors.forename: Subhajit
authors.initials: S
authors.lastname: Mukherjee
authors.affiliation: Department of Physiology and Pharmacology (A.G., A.Z., S.L.E., L.A., S.A.H.), and Department of Microbiology, Immunology and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (Su.M., Sr.M.); and Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (A.J.L., T.K.H.C.).
authors.forename: Aik Jiang
authors.initials: AJ
authors.lastname: Lau
authors.affiliation: Department of Physiology and Pharmacology (A.G., A.Z., S.L.E., L.A., S.A.H.), and Department of Microbiology, Immunology and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (Su.M., Sr.M.); and Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (A.J.L., T.K.H.C.).
authors.forename: Laurie
authors.initials: L
authors.lastname: Alston
authors.affiliation: Department of Physiology and Pharmacology (A.G., A.Z., S.L.E., L.A., S.A.H.), and Department of Microbiology, Immunology and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (Su.M., Sr.M.); and Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (A.J.L., T.K.H.C.).
authors.forename: Thomas K H
authors.initials: TK
authors.lastname: Chang
authors.affiliation: Department of Physiology and Pharmacology (A.G., A.Z., S.L.E., L.A., S.A.H.), and Department of Microbiology, Immunology and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (Su.M., Sr.M.); and Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (A.J.L., T.K.H.C.).
authors.forename: Sridhar
authors.initials: S
authors.lastname: Mani
authors.affiliation: Department of Physiology and Pharmacology (A.G., A.Z., S.L.E., L.A., S.A.H.), and Department of Microbiology, Immunology and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (Su.M., Sr.M.); and Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (A.J.L., T.K.H.C.) simon.hirota@ucalgary.ca.
authors.forename: Simon A
authors.initials: SA
authors.lastname: Hirota
mesh_terms: D000818:Animals; D018938:Caco-2 Cells; D003092:Colitis / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology; D016207:Cytokines / Q000494:pharmacology*; D016264:Dextran Sulfate / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D056945:Hep G2 Cells; D006801:Humans; D007249:Inflammation / Q000378:metabolism / Q000473:pathology; D007371:Interferon-gamma / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D048055:Mitogen-Activated Protein Kinase 8 / Q000378:metabolism*; D048056:Mitogen-Activated Protein Kinase 9 / Q000378:metabolism*; D009219:Myosin-Light-Chain Kinase / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D000077297:Pregnane X Receptor; D011987:Receptors, Steroid / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D051197:Toll-Like Receptor 4 / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D016207:Cytokines; D016328:NF-kappa B; C000625852:NR1I2 protein, human; C000625853:Nr1i2 protein, mouse; D000077297:Pregnane X Receptor; D011987:Receptors, Steroid; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma; D016264:Dextran Sulfate; D048056:Mitogen-Activated Protein Kinase 9; D009219:Myosin-Light-Chain Kinase; D048055:Mitogen-Activated Protein Kinase 8