Document Detail

Inhibition of basal p38 or JNK activity enhances epithelial barrier function through differential modulation of claudin expression.
MedLine Citation:
PMID:  19605737     Owner:  NLM     Status:  MEDLINE    
Tight junctions (TJs) form a barrier to the paracellular diffusion of ions and solutes across epithelia. Although transmembrane proteins of the claudin family have emerged as critical determinants of TJ permeability, little is known about the signaling pathways that control their expression. The aim of this study was to assess the role of three mitogen-activated protein kinases (MAPKs), i.e., extracellular signal-regulated kinase-1/2 (ERK1/2), c-Jun NH(2)-terminal kinases (JNKs), and p38 kinases, in the regulation of epithelial barrier function and claudin expression in mammary epithelial cells. Addition of either PD169316 (a p38 inhibitor) or SP600125 (a JNK inhibitor) induced formation of domes (a phenomenon dependent on TJ barrier function) and enhanced transepithelial electrical resistance, whereas U0126 (an inhibitor of the ERK1/2 activators MEK1/MEK2) had no significant effect. Similar results were obtained using mechanistically unrelated p38 or JNK inhibitors. PD169316 increased the expression of claudin-4 and -8, whereas SP600125 increased claudin-4 and -9 and downregulated claudin-8. Silencing of p38alpha by isoform-specific small interfering RNAs increased claudin-4 and -8 mRNAs, whereas silencing of p38beta only increased claudin-4 mRNA. Silencing of either JNK1 or JNK2 increased claudin-9 mRNA expression while decreasing claudin-8 mRNA. Moreover, selective silencing of JNK2 increased claudin-4 and -7 mRNAs. Finally, both PD169316 and SP600125 inhibited the paracellular diffusion of Na(+) and Cl(-) across epithelial monolayers. Collectively, these results provide evidence that inhibition of either p38 or JNK enhances epithelial barrier function by selectively modulating claudin expression, implying that the basal activity of these MAPKs exerts a tonic effect on TJ ionic permeability.
Fabio Carrozzino; Paolo Pugnale; Eric F??raille; Roberto Montesano
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-07-15
Journal Detail:
Title:  American journal of physiology. Cell physiology     Volume:  297     ISSN:  1522-1563     ISO Abbreviation:  Am. J. Physiol., Cell Physiol.     Publication Date:  2009 Sep 
Date Detail:
Created Date:  2009-09-07     Completed Date:  2009-10-05     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100901225     Medline TA:  Am J Physiol Cell Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  C775-87     Citation Subset:  IM    
Dept. of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
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MeSH Terms
Anthracenes / pharmacology
Butadienes / pharmacology
Cell Line
Epithelium / physiology*
Imidazoles / pharmacology
MAP Kinase Kinase 4 / antagonists & inhibitors,  metabolism*
Mammary Glands, Animal / cytology
Membrane Proteins / genetics,  metabolism*
Nitriles / pharmacology
p38 Mitogen-Activated Protein Kinases / antagonists & inhibitors,  metabolism*
Reg. No./Substance:
0/Anthracenes; 0/Butadienes; 0/Imidazoles; 0/Membrane Proteins; 0/Nitriles; 0/PD 169316; 0/U 0126; 0/anthra(1,9-cd)pyrazol-6(2H)-one; EC 2.7.1.-/MAP Kinase Kinase 4; EC Mitogen-Activated Protein Kinases

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