Document Detail


Bile acids modulate tight junction structure and barrier function of Caco-2 monolayers via EGFR activation.
MedLine Citation:
PMID:  18239063     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Intestinal and systemic illnesses have been linked to increased gut permeability. Bile acids, whose luminal profile can be altered in human disease, modulate intestinal paracellular permeability. We investigated the mechanism by which selected bile acids increase gut permeability using a validated in vitro model. Human intestinal Caco-2 cells were grown in monolayers and challenged with a panel of bile acids. Transepithelial electrical resistance and luminal-to-basolateral fluxes of 10-kDa Cascade blue-conjugated dextran were used to monitor paracellular permeability. Immunoprecipitation and immunoblot analyses were employed to investigate the intracellular pathway. Redistribution of tight junction proteins was studied by confocal laser microscopy. Micromolar concentrations of cholic acid, deoxycholic acid (DCA), and chenodeoxycholic acid (CDCA) but not ursodeoxycholic acid decreased transepithelial electrical resistance and increased dextran flux in a reversible fashion. Coincubation of 50 muM CDCA or DCA with EGF, anti-EGF monoclonal antibody, or specific src inhibitor 4-Amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP-2) abolished the effect. A concentration of 50 muM of either CDCA or DCA also induced EGF receptor phosphorylation, occludin dephosphorylation, and occludin redistribution at the tight junction level in the same time frame and in a reversible fashion. We conclude that selected bile acids modulate intestinal permeability via EGF receptor autophosphorylation, occludin dephosphorylation, and rearrangement at the tight junction level. The effect is mediated by the src family kinases and is abolished by EGF treatment. These data also support the role of bile acids in the genesis of necrotizing enterocolitis and the protective effect of EGF treatment.
Authors:
Francesco Raimondi; Pasquale Santoro; Maria Vittoria Barone; Serena Pappacoda; Maria Luisa Barretta; Merlin Nanayakkara; Carmela Apicella; Letizia Capasso; Roberto Paludetto
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Publication Detail:
Type:  Journal Article     Date:  2008-01-31
Journal Detail:
Title:  American journal of physiology. Gastrointestinal and liver physiology     Volume:  294     ISSN:  0193-1857     ISO Abbreviation:  Am. J. Physiol. Gastrointest. Liver Physiol.     Publication Date:  2008 Apr 
Date Detail:
Created Date:  2008-04-09     Completed Date:  2008-05-22     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  100901227     Medline TA:  Am J Physiol Gastrointest Liver Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  G906-13     Citation Subset:  IM    
Affiliation:
Division of Neonatology, Department of Pediatrics, "Federico II" University, Naples, Italy.
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MeSH Terms
Descriptor/Qualifier:
Antibodies, Monoclonal
Bile Acids and Salts / metabolism*
Caco-2 Cells
Chenodeoxycholic Acid / metabolism
Cholic Acid / metabolism
Deoxycholic Acid / metabolism
Dextrans / metabolism
Electric Impedance
Enzyme Activation
Epidermal Growth Factor / metabolism
Humans
Intestinal Mucosa / drug effects,  enzymology,  metabolism*
Kinetics
Membrane Proteins / metabolism
Organometallic Compounds / metabolism
Organophosphorus Compounds / metabolism
Permeability
Phosphorylation
Protein Kinase Inhibitors / pharmacology
Pyrimidines / pharmacology
Receptor, Epidermal Growth Factor / immunology,  metabolism*
Tight Junctions / drug effects,  enzymology,  metabolism*
src-Family Kinases / antagonists & inhibitors,  metabolism
Chemical
Reg. No./Substance:
0/AG 1879; 0/Antibodies, Monoclonal; 0/Bile Acids and Salts; 0/Membrane Proteins; 0/Organometallic Compounds; 0/Organophosphorus Compounds; 0/Protein Kinase Inhibitors; 0/Pyrimidines; 0/occludin; 1325-87-7/Cascade Blue; 474-25-9/Chenodeoxycholic Acid; 62229-50-9/Epidermal Growth Factor; 81-25-4/Cholic Acid; 83-44-3/Deoxycholic Acid; 9004-54-0/Dextrans; EC 2.7.10.1/EGFR protein, human; EC 2.7.10.1/Receptor, Epidermal Growth Factor; EC 2.7.10.2/src-Family Kinases

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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