title: Implication of TNF-related apoptosis-inducing ligand in inflammatory intestinal epithelial lesions.
abstract: OBJECTIVE
  Few data exist on the molecular events causing intestinal epithelial destruction during inflammatory processes, such as inflammatory bowel disease (IBD). In this work, we analyzed the potential implication of tumor necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL) in these inflammatory lesions.
  
  
  METHODS
  TRAIL and TRAIL-receptor expression were analyzed in normal, inflammatory ileum/colon and human intestinal epithelial cell (IEC) lines (HIEC), Caco-2, and HT-29 using RNase protection assay, real-time and reverse-transcription polymerase chain reaction (RT-PCR), immunohistochemistry, and Western blot analysis. TRAIL-induced activation of NF-kappaB was determined by electrophoretic mobility shift assay. Caspase-recruitment domain (CARD)15 expression and interleukin-(IL)8 production were studied by RT-PCR and enzyme-linked immunosorbent assay. Apoptosis was monitored using Annexin-V/caspase-3 assays.
  
  
  RESULTS
  Normal mature IEC expressed low TRAIL levels, whereas, in inflammatory lesions, TRAIL messenger RNA and protein were markedly up-regulated in IEC and lamina propria lymphocytes at levels comparable with trinitrobenzene sulfonic acid-induced colitis. Interferon-gamma and TNF-alpha potently induced TRAIL in IEC. In vitro analyses revealed a dual biologic effect of TRAIL on HIEC: Under noninflammatory conditions, TRAIL up-regulated via nuclear factor-kappaB CARD15 and IL-8, whereas, under inflammatory conditions, TRAIL became a potent inducer of apoptosis in HIEC, which was confirmed ex vivo using ileal organ cultures. TNF-alpha markedly increased the expression of the proapoptotic receptor TRAIL-R2. TRAIL-induced IEC apoptosis required a functional caspase cascade.
  
  
  CONCLUSIONS
  TRAIL is a new inflammatory mediator implicated in the homeostasis of intestinal epithelial barrier functions. TRAIL is highly up-regulated in IEC in inflammatory ileum and colon. It may augment in an auto-/paracrine fashion the elimination of IEC via apoptosis.
authors.affiliation: INSERM U793, Faculté de Médecine Necker, Université Paris V, Paris, France.
authors.forename: Bernadette
authors.initials: B
authors.lastname: Begue
authors.forename: Harald
authors.initials: H
authors.lastname: Wajant
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Bambou
authors.forename: Laurent
authors.initials: L
authors.lastname: Dubuquoy
authors.forename: Daniela
authors.initials: D
authors.lastname: Siegmund
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Beaulieu
authors.forename: Danielle
authors.initials: D
authors.lastname: Canioni
authors.forename: Dominique
authors.initials: D
authors.lastname: Berrebi
authors.forename: Nicole
authors.initials: N
authors.lastname: Brousse
authors.forename: Pierre
authors.initials: P
authors.lastname: Desreumaux
authors.forename: Jacques
authors.initials: J
authors.lastname: Schmitz
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Lentze
authors.forename: Oliver
authors.initials: O
authors.lastname: Goulet
authors.forename: Nadine
authors.initials: N
authors.lastname: Cerf-Bensussan
authors.forename: Frank M
authors.initials: FM
authors.lastname: Ruemmele
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D051017:Apoptosis Regulatory Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D015153:Blotting, Western; D002478:Cells, Cultured; D004195:Disease Models, Animal; D004847:Epithelial Cells / Q000166:cytology* / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D005786:Gene Expression Regulation; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism*; D015212:Inflammatory Bowel Diseases / Q000235:genetics / Q000473:pathology; D016209:Interleukin-8 / Q000378:metabolism*; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D012016:Reference Values; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D053221:TNF-Related Apoptosis-Inducing Ligand; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics* / Q000378:metabolism
chemical_list: D051017:Apoptosis Regulatory Proteins; D018836:Inflammation Mediators; D016209:Interleukin-8; D008562:Membrane Glycoproteins; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; C505654:Tnfsf10 protein, mouse; D014409:Tumor Necrosis Factor-alpha