title: Cytokine regulation of pro- and anti-apoptotic genes in rat hepatocytes: NF-kappaB-regulated inhibitor of apoptosis protein 2 (cIAP2) prevents apoptosis.
abstract: OBJECTIVE
  In acute liver failure, hepatocytes are exposed to various cytokines that activate both cell survival and apoptotic pathways. NF-kappaB is a central transcription factor in these responses. Recent studies indicate that blocking NF-kappaB causes apoptosis, indicating the existence of NF-kappaB-regulated anti-apoptotic genes. In the present study the relationship between NF-kappaB activation and apoptosis has been investigated in hepatocytes.
  
  
  METHODS
  Primary rat hepatocytes were exposed to a cytokine mixture of tumor necrosis factor alpha, interleukin-1beta, interferon-gamma and lipopolysaccharide. Modulation of signalling pathways was performed by using dominant negative adenoviral constructs. Apoptosis and NF-kappaB activation were determined by caspase-3 activity, Hoechst staining and electrophoretic mobility shift assay, respectively. Furthermore, expression and regulation of apoptosis-related genes were investigated.
  
  
  RESULTS
  (1) Inhibition of NF-kappaB activation results in apoptosis. (2) Inhibitor of apoptosis protein (IAP) family members, inhibitor of apoptosis protein1 (cIAP1), and X-chromosome-linked IAP, are expressed in rat hepatocytes. cIAP2 is induced by cytokines in an NF-kappaB-dependent manner and overexpression of cIAP2 inhibits apoptosis. (3) The anti-apoptotic Bcl-2 family member A1/Bfl-1 and the pro-apoptotic members Bak and Bid are induced by cytokines and NF-kappaB-dependent. (4) Nitric oxide inhibits caspase-3 activity in hepatocytes.
  
  
  CONCLUSIONS
  In inflammatory conditions, hepatocyte survival is dependent on NF-kappaB activation and cIAP2 contributes significantly to this protection.
authors.affiliation: Center for Liver, Digestive and Metabolic Diseases, University Hospital Groningen, PO Box 30.001, 9700 RB, Groningen, The Netherlands. m.h.schoemaker@med.rug.nl
authors.forename: Marieke H
authors.initials: MH
authors.lastname: Schoemaker
authors.forename: Jenny E
authors.initials: JE
authors.lastname: Ros
authors.forename: Manon
authors.initials: M
authors.lastname: Homan
authors.forename: Christian
authors.initials: C
authors.lastname: Trautwein
authors.forename: Peter
authors.initials: P
authors.lastname: Liston
authors.forename: Klaas
authors.initials: K
authors.lastname: Poelstra
authors.forename: Harry
authors.initials: H
authors.lastname: van Goor
authors.forename: Peter L M
authors.initials: PL
authors.lastname: Jansen
authors.forename: Han
authors.initials: H
authors.lastname: Moshage
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D000970:Antineoplastic Agents / Q000378:metabolism / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D053148:Caspase 3; D061945:Caspase Inhibitors; D016207:Cytokines / Q000378:metabolism / Q000494:pharmacology*; D015870:Gene Expression; D006505:Hepatitis / Q000378:metabolism; D022781:Hepatocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D007371:Interferon-gamma / Q000378:metabolism / Q000494:pharmacology; D007375:Interleukin-1 / Q000378:metabolism / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D016328:NF-kappa B / Q000378:metabolism*; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; D061945:Caspase Inhibitors; D016207:Cytokines; D007375:Interleukin-1; D008070:Lipopolysaccharides; D016328:NF-kappa B; D011506:Proteins; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma; C505410:Casp3 protein, rat; D053148:Caspase 3