title: Role of epithelial integrin-linked kinase in promoting intestinal inflammation: effects on CCL2, fibronectin and the T cell repertoire.
abstract: BACKGROUND
  The role of integrin signaling in mucosal inflammation is presently unknown. Hence, we aimed to investigate the role of epithelial-derived integrin-linked kinase (ILK), a critical integrin signaling intermediary molecule, in colonic inflammation.
  
  
  METHODS
  Conditional intestinal epithelial cell ILK knockout mice were used for assessment of acute and chronic dextran sodium sulfate (DSS)-induced colitis. Disease activity was scored using standard histological scoring, mucosal cytokines were measured using ELISA, chemokines were determined using reverse-transcription polymerase chain reaction, as well as Q-PCR, and intracellular cytokine staining performed using FACS analysis.
  
  
  RESULTS
  In both acute and chronic DSS-induced colitis, compared to wild-type mice, ILK-ko mice exhibit less weight loss, and have reduced inflammatory scores. In an in vitro model system using HCT116 cells, we demonstrate that si-RNA mediated down-regulation of ILK results in a reduction in monocyte chemoattractant protein 1 (MCP1, CCL2) chemokine expression. A reduction in CCL2 levels is also observed in the tissue lysates of chronically inflamed colons from ILK-ko mice. Examination of mesenteric lymph node lymphocytes from ILK-ko mice reveals that there is a reduction in the levels of IFN gamma using intracellular staining, together with an increase in Foxp3+ T regulatory cells. Immunohistochemistry demonstrates that reduced fibronectin expression characterizes the inflammatory lesions within the colons of ILK-ko mice. Intriguingly, we demonstrate that fibronectin is directly capable of downregulating T regulatory cell development.
  
  
  CONCLUSIONS
  Collectively, the data indicate for the first time that ILK plays a pro-inflammatory role in intestinal inflammation, through effects on chemokine expression, the extracellular matrix and immune tolerance.
authors.affiliation: Department of Medicine, The Jack Bell Research Centre, 2660 Oak Street, Vancouver, British Columbia, V6H 3Z6, Canada.
authors.forename: Kiran
authors.initials: K
authors.lastname: Assi
authors.forename: Scott
authors.initials: S
authors.lastname: Patterson
authors.forename: Shoukat
authors.initials: S
authors.lastname: Dedhar
authors.forename: David
authors.initials: D
authors.lastname: Owen
authors.forename: Megan
authors.initials: M
authors.lastname: Levings
authors.forename: Baljinder
authors.initials: B
authors.lastname: Salh
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D018932:Chemokine CCL2 / Q000096:biosynthesis / Q000378:metabolism*; D003092:Colitis / Q000139:chemically induced / Q000201:enzymology* / Q000276:immunology*; D004847:Epithelial Cells / Q000201:enzymology*; D005260:Female; D005353:Fibronectins / Q000276:immunology / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D045325:HCT116 Cells; D006801:Humans; D007155:Immunologic Factors / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000378:metabolism; D015431:Weight Loss / Q000235:genetics; D000099200:Scaffold Protein ILK
chemical_list: D018932:Chemokine CCL2; D005353:Fibronectins; D007155:Immunologic Factors; D008070:Lipopolysaccharides; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D000099200:Scaffold Protein ILK