Chemokine receptor CCR6 transduces signals that activate p130Cas and alter cAMP-stimulated ion transport in human intestinal epithelial cells.
Human colon epithelial cells express the G protein-coupled receptor CCR6, the sole receptor for the chemokine CCL20 (also termed MIP-3alpha). CCL20 produced by intestinal epithelial cells is upregulated in response to proinflammatory stimuli and microbial infection, and it chemoattracts leukocytes, including CCR6-expressing immature myeloid dendritic cells, into sites of inflammation. The aim of this study was to determine whether CCR6 expressed by intestinal epithelial cells acts as a functional receptor for CCL20 and whether stimulation with CCL20 alters intestinal epithelial cell functions. The human colon epithelial cell lines T84, Caco-2, HT-29, and HCA-7 were used to model colonic epithelium. Polarized intestinal epithelial cells constitutively expressed CCR6, predominantly on the apical side. Consistent with this, apical stimulation of polarized intestinal epithelial cells resulted in tyrosine phosphorylation of the p130 Crk-associated substrate (Cas), an adaptor/scaffolding protein that localizes in focal adhesions and has a role in regulating cytoskeletal elements important for cell attachment and migration. In addition, CCL20 stimulation inhibited agonist-stimulated production of the second messenger cAMP and cAMP-mediated chloride secretory responses by intestinal epithelial cells. Inhibition was abrogated by pertussis toxin, consistent with signaling through Galphai proteins that negatively regulate adenylyl cyclases and cAMP production. These data indicate that signaling events, occurring via the activation of the apically expressed chemokine receptor CCR6 on polarized intestinal epithelial cells, alter specialized intestinal epithelial cell functions, including electrogenic ion secretion and possibly epithelial cell adhesion and migration.
Laboratory of Mucosal Immunology, Department of Medicine, University of California, San Diego, La Jolla, California 92093-0623, USA.
Charles C
CC
Yang
Hiroyuki
H
Ogawa
Michael B
MB
Dwinell
Declan F
DF
McCole
Lars
L
Eckmann
Martin F
MF
Kagnoff
D015153:Blotting, Western; D018938:Caco-2 Cells; D054418:Chemokine CCL20; D019742:Chemokines, CC / Q000378:metabolism / Q000494:pharmacology; D050719:Crk-Associated Substrate Protein; D000242:Cyclic AMP / Q000378:metabolism; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D005434:Flow Cytometry; D044385:GTP-Binding Protein alpha Subunits / Q000378:metabolism; D019073:HT29 Cells; D006801:Humans; D047468:Immunoprecipitation; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism; D017136:Ion Transport / Q000187:drug effects / Q000502:physiology*; D019402:Macrophage Inflammatory Proteins / Q000378:metabolism / Q000494:pharmacology; D018613:Microscopy, Confocal; D018408:Patch-Clamp Techniques; D011506:Proteins / Q000378:metabolism*; D054399:Receptors, CCR6; D019707:Receptors, Chemokine / Q000378:metabolism*; D050717:Retinoblastoma-Like Protein p130; D015290:Second Messenger Systems / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*
C493841:BCAR1 protein, human; C108355:CCL20 protein, human; C106311:CCR6 protein, human; D054418:Chemokine CCL20; D019742:Chemokines, CC; D050719:Crk-Associated Substrate Protein; D044385:GTP-Binding Protein alpha Subunits; D019402:Macrophage Inflammatory Proteins; D011506:Proteins; D054399:Receptors, CCR6; D019707:Receptors, Chemokine; D050717:Retinoblastoma-Like Protein p130; D000242:Cyclic AMP