title: Selective downregulation of retinoic acid-inducible gene I within the intestinal epithelial compartment in Crohn's disease.
abstract: BACKGROUND
  A defective innate immune response may contribute to the pathogenesis of Crohn's disease (CD) and ulcerative colitis (UC). Employing a global gene expression analysis, this study was aimed at identifying specifically regulated genes within the epithelial compartment in inflammatory bowel disease (IBD).
  
  
  METHODS
  The epithelial fraction of human ileal mucosa samples from surgical specimens was obtained by laser microdissection. Gene expression was examined by global expression profiling (n = 18, Affymetrix), quantitative reverse-transcription polymerase chain reaction (RT-PCR) (n = 35), immunoblot analysis (n = 9), and immunohistochemistry (n = 25).
  
  
  RESULTS
  Global expression profiling revealed a pronounced downregulation of the retinoic acid-inducible gene I (RIG-I) within the epithelial layer of the ileum in patients with CD but not with UC. The downregulation of RIG-I was confirmed by quantitative RT-PCR, immunoblot analysis, and immunohistochemistry.
  
  
  CONCLUSIONS
  Epithelial downregulation of RIG-I, a known pattern recognition receptor for viral components, might contribute to alterations of the innate mucosal immune response, particularly in CD.
authors.affiliation: Institute of Pathology, University Hospital Heidelberg, Heidelberg, Germany. benjamin.funke@med.uni-heidelberg.de
authors.forename: Benjamin
authors.initials: B
authors.lastname: Funke
authors.forename: Felix
authors.initials: F
authors.lastname: Lasitschka
authors.forename: Wilfried
authors.initials: W
authors.lastname: Roth
authors.forename: Roland
authors.initials: R
authors.lastname: Penzel
authors.forename: Stefan
authors.initials: S
authors.lastname: Meuer
authors.forename: Maria
authors.initials: M
authors.lastname: Saile
authors.forename: Norbert
authors.initials: N
authors.lastname: Gretz
authors.forename: Bernd
authors.initials: B
authors.lastname: Sido
authors.forename: Peter
authors.initials: P
authors.lastname: Schirmacher
authors.forename: Frank
authors.initials: F
authors.lastname: Autschbach
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000032:analysis* / Q000378:metabolism; D015153:Blotting, Western; D016022:Case-Control Studies; D015331:Cohort Studies; D003093:Colitis, Ulcerative / Q000235:genetics* / Q000378:metabolism; D003424:Crohn Disease / Q000235:genetics* / Q000378:metabolism; D000071457:DEAD Box Protein 58; D053487:DEAD-box RNA Helicases / Q000235:genetics* / Q000378:metabolism; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D007124:Immunoenzyme Techniques; D007413:Intestinal Mucosa / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D020411:Oligonucleotide Array Sequence Analysis; D011379:Prognosis; D012333:RNA, Messenger / Q000235:genetics; D011971:Receptors, Immunologic; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D015415:Biomarkers; D012333:RNA, Messenger; D011971:Receptors, Immunologic; C452820:RIGI protein, human; D000071457:DEAD Box Protein 58; D053487:DEAD-box RNA Helicases