title: Regulation of hepatic EAAT-2 glutamate transporter expression in human liver cholestasis.
abstract: OBJECTIVE
  To investigate the activity and expression of EAAT2 glutamate transporter in both in vitro and in vivo models of cholestasis.
  
  
  METHODS
  This study was conducted on human hepatoblastoma HepG2 cell cultures, the liver of bile duct ligated rats and human specimens from cholestatic patients. EAAT2 glutamate transporter activity and expression were analyzed using a substrate uptake assay, immunofluorescence, reverse transcription-polymerase chain reaction, and immunohistochemistry, respectively.
  
  
  RESULTS
  In HepG2 cells, cholestasis was mimicked by treating cells with the protein kinase C activator, phorbol 12-myristate 13-acetate. Under such conditions, EAAT2 transporter activity was decreased both at the level of substrate affinity and maximal transport velocity. The decreased uptake was correlated with intracellular translocation of EAAT2 molecules as demonstrated using immunofluorescence. In the liver of bile duct ligated rats, an increase in EAAT2 transporter protein expression in hepatocytes was demonstrated using immunohistochemistry. The same findings were observed in human liver specimens of cholestasis in which high levels of γ-glutamyl transpeptidase were documented in patients with biliary atresia and progressive familial intrahepatic cholestasis type 3.
  
  
  CONCLUSIONS
  This study demonstrates the alteration in glutamate handling by hepatocytes in liver cholestasis and suggests a potential cross-talk between glutamatergic and bile systems.
authors.affiliation: Mustapha Najimi, Xavier Stéphenne, Etienne Sokal, Université Catholique de Louvain, Institut de Recherche Expérimentale et Clinique (IREC), Laboratory of Pediatric Hepatology and Cell Therapy, Brussels 1200, Belgium.
authors.forename: Mustapha
authors.initials: M
authors.lastname: Najimi
authors.affiliation: Mustapha Najimi, Xavier Stéphenne, Etienne Sokal, Université Catholique de Louvain, Institut de Recherche Expérimentale et Clinique (IREC), Laboratory of Pediatric Hepatology and Cell Therapy, Brussels 1200, Belgium.
authors.forename: Xavier
authors.initials: X
authors.lastname: Stéphenne
authors.affiliation: Mustapha Najimi, Xavier Stéphenne, Etienne Sokal, Université Catholique de Louvain, Institut de Recherche Expérimentale et Clinique (IREC), Laboratory of Pediatric Hepatology and Cell Therapy, Brussels 1200, Belgium.
authors.forename: Christine
authors.initials: C
authors.lastname: Sempoux
authors.affiliation: Mustapha Najimi, Xavier Stéphenne, Etienne Sokal, Université Catholique de Louvain, Institut de Recherche Expérimentale et Clinique (IREC), Laboratory of Pediatric Hepatology and Cell Therapy, Brussels 1200, Belgium.
authors.forename: Etienne
authors.initials: E
authors.lastname: Sokal
mesh_terms: D000818:Animals; D002779:Cholestasis / Q000378:metabolism* / Q000601:surgery; D027342:Excitatory Amino Acid Transporter 2 / Q000378:metabolism*; D005786:Gene Expression Regulation; D050491:Glutamate Plasma Membrane Transport Proteins / Q000378:metabolism*; D056945:Hep G2 Cells; D006801:Humans; D007150:Immunohistochemistry; D008099:Liver / Q000378:metabolism; D008107:Liver Diseases / Q000378:metabolism*; D008297:Male; D008856:Microscopy, Fluorescence; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D027342:Excitatory Amino Acid Transporter 2; D050491:Glutamate Plasma Membrane Transport Proteins; C493397:SLC1A2 protein, human; C493395:Slc1a2 protein, rat
keywords: Bile duct ligation; Biliary atresia; Cholestasis; Glutamate transport; Hepatocyte