title: Effects of proinflammatory cytokines on rat organic anion transporters during toxic liver injury and cholestasis.
abstract: Hepatobiliary transporters are down-regulated in toxic and cholestatic liver injury. Cytokines such as tumor necrosis factor alpha (TNF-alpha) and interleukin 1 beta (IL-1 beta) are attributed to mediate this regulation, but their particular contribution in vivo is still unknown. Thus, we studied the molecular mechanisms by which Ntcp, Oatp1, Oatp2, and Mrp2 are regulated by proinflammatory cytokines during liver injury. Rats were injected intraperitoneally with either carbon tetrachloride or endotoxin. Inactivation of TNF-alpha and IL-1 beta was achieved by repetitive intraperitoneal injection of etanercept and anakinra, respectively. Messenger RNA (mRNA) levels of transporters and binding activities as well as nuclear protein levels of Ntcp, Oatp2, and Mrp2 transactivators were determined 20 to 24 hours later. In contrast to IL-1 beta, TNF-alpha inactivation alone fully prevented down-regulation of Ntcp, Oatp1, and Oatp2 mRNA as well as reduced binding activity of hepatocyte nuclear factor 1 (HNF-1) in CCl(4)-induced toxic injury. In endotoxemia, down-regulation of Mrp2, and partially in case of Ntcp, could be prevented by IL-1 beta but not TNF-alpha blockade. However, inactivation of either cytokine led to preservation of HNF1 and partially of retinoid X receptor/retinoic acid receptor (RXR/RAR) binding activity. No effect of anticytokines was seen on pregnane X receptor (PXR) and constitutive androstane receptor (CAR) binding activity as well as nuclear protein mass. In conclusion, TNF-alpha represents the master cytokine responsible for HNF1-dependent down-regulation of Ntcp, Oatp1, and Oatp2 in CCl(4)-induced toxic liver injury. IL-1 beta predominates in a complex signaling network of Ntcp and Mrp2 regulation in cholestatic liver injury. In contrast to in vitro studies, HNF1 and RXR/RAR-independent mechanisms appear to be more important in regulation of Mrp2 and Ntcp gene expression in endotoxemia.
authors.affiliation: Department of Internal Medicine III, University of Technology Aachen, Aachen, Germany. agreier@ukaachen.de
authors.forename: Andreas
authors.initials: A
authors.lastname: Geier
authors.forename: Christoph G
authors.initials: CG
authors.lastname: Dietrich
authors.forename: Sebastian
authors.initials: S
authors.lastname: Voigt
authors.forename: Suk-Kyum
authors.initials: SK
authors.lastname: Kim
authors.forename: Thomas
authors.initials: T
authors.lastname: Gerloff
authors.forename: Gerd A
authors.initials: GA
authors.lastname: Kullak-Ublick
authors.forename: Johann
authors.initials: J
authors.lastname: Lorenzen
authors.forename: Siegfried
authors.initials: S
authors.lastname: Matern
authors.forename: Carsten
authors.initials: C
authors.lastname: Gartung
mesh_terms: D018528:ATP-Binding Cassette Transporters; D000818:Animals; D018501:Antirheumatic Agents / Q000494:pharmacology; D002251:Carbon Tetrachloride; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D056486:Chemical and Drug Induced Liver Injury / Q000276:immunology / Q000378:metabolism*; D002780:Cholestasis, Intrahepatic / Q000276:immunology / Q000378:metabolism*; D000068800:Etanercept; D015870:Gene Expression / Q000502:physiology; D007074:Immunoglobulin G / Q000494:pharmacology; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008297:Male; D026901:Membrane Transport Proteins; D009687:Nuclear Proteins / Q000378:metabolism; D027361:Organic Anion Transporters; D029363:Organic Anion Transporters, Sodium-Dependent; D029362:Organic Anion Transporters, Sodium-Independent / Q000235:genetics / Q000378:metabolism*; D027701:Organic Cation Transport Proteins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D018124:Receptors, Tumor Necrosis Factor; D012795:Sialoglycoproteins / Q000494:pharmacology; D027981:Symporters; D014157:Transcription Factors / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D018528:ATP-Binding Cassette Transporters; C423013:Abcc2 protein, rat; D018501:Antirheumatic Agents; D002352:Carrier Proteins; D007074:Immunoglobulin G; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1; D026901:Membrane Transport Proteins; D009687:Nuclear Proteins; D027361:Organic Anion Transporters; D029363:Organic Anion Transporters, Sodium-Dependent; D029362:Organic Anion Transporters, Sodium-Independent; D027701:Organic Cation Transport Proteins; D012333:RNA, Messenger; D018124:Receptors, Tumor Necrosis Factor; D012795:Sialoglycoproteins; C421102:Slco1a1 protein, rat; C503597:Slco1a4 protein, rat; C451262:Slco1c1 protein, rat; D027981:Symporters; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha; C071908:sodium-bile acid cotransporter; D002251:Carbon Tetrachloride; D000068800:Etanercept