IL-22 is increased in active Crohn's disease and promotes proinflammatory gene expression and intestinal epithelial cell migration.
IL-22 is produced by activated T cells and signals through a receptor complex consisting of IL-22R1 and IL-10R2. The aim of this study was to analyze IL-22 receptor expression, signal transduction, and specific biological functions of this cytokine system in intestinal epithelial cells (IEC). Expression studies were performed by RT-PCR. Signal transduction was analyzed by Western blot experiments, cell proliferation by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay and Fas-induced apoptosis by flow cytometry. IEC migration was studied in wounding assays. The IEC lines Caco-2, DLD-1, SW480, HCT116, and HT-29 express both IL-22 receptor subunits IL-22R1 and IL-10R2. Stimulation with TNF-alpha, IL-1beta, and LPS significantly upregulated IL-22R1 without affecting IL-10R2 mRNA expression. IL-22 binding to its receptor complex activates STAT1/3, Akt, ERK1/2, and SAPK/JNK MAP kinases. IL-22 significantly increased cell proliferation (P = 0.002) and phosphatidylinsitol 3-kinase-dependent IEC cell migration (P < 0.00001) as well as mRNA expression of TNF-alpha, IL-8, and human beta-defensin-2. IL-22 had no effect on Fas-induced apoptosis. IL-22 mRNA expression was increased in inflamed colonic lesions of patients with Crohn's disease and correlated highly with the IL-8 expression in these lesions (r = 0.840). Moreover, IL-22 expression was increased in murine dextran sulfate sodium-induced colitis. IEC express functional receptors for IL-22, which increases the expression of proinflammatory cytokines and promotes the innate immune response by increased defensin expression. Moreover, our data indicate intestinal barrier functions for this cytokine-promoting IEC migration, which suggests an important function in intestinal inflammation and wound healing. IL-22 is increased in active Crohn's disease and promotes proinflammatory gene expression and IEC migration.
Department of Medicine II, University-Hospital Munich-Grosshadern, University of Munich, Germany. stephan.brand@med.uni-muenchen.de
Stephan
S
Brand
Florian
F
Beigel
Torsten
T
Olszak
Kathrin
K
Zitzmann
Sören T
ST
Eichhorst
Jan-Michel
JM
Otte
Helmut
H
Diepolder
Andreas
A
Marquardt
Wolfgang
W
Jagla
Andreas
A
Popp
Stéphane
S
Leclair
Karin
K
Herrmann
Julia
J
Seiderer
Thomas
T
Ochsenkühn
Burkhard
B
Göke
Christoph J
CJ
Auernhammer
Julia
J
Dambacher
D002465:Cell Movement; D002478:Cells, Cultured; D003424:Crohn Disease / Q000276:immunology* / Q000473:pathology*; D004847:Epithelial Cells / Q000276:immunology / Q000473:pathology; D005786:Gene Expression Regulation / Q000276:immunology*; D006801:Humans; D007249:Inflammation / Q000235:genetics; D007378:Interleukins / Q000276:immunology*; D007413:Intestinal Mucosa / Q000276:immunology* / Q000473:pathology*; D000097043:Interleukin-22
D007378:Interleukins; D000097043:Interleukin-22