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.
Copyright © 2011 Crohn's & Colitis Foundation of America, Inc.