Flagellin of Pseudomonas Aeruginosa Inhibits Na+ Transport in Airway Epithelia.
From: Institut für Physiologie, Universität Regensburg, Regensburg, Germany. uqkkunze@mailbox.uq.edu.au
The FASEB journal : official publication of the Federation of American Societies for Experimental Biology
- Publish Date: Mar 2006
- ISSN: 1530-6860
- Volume: 20
- Issue: 3
- Pages: 545-6
- Medium: Internet
- Language: English
- Citation (JAMA): Kunzelmann Karl, Scheidt Kerstin, Scharf Birgit, et al. Flagellin of Pseudomonas Aeruginosa Inhibits Na+ Transport in Airway Epithelia.. FASEB J. Mar 2006;20:545-6
Abstract
Pseudomonas aeruginosa causes severe life-threatening airway infections that are a frequent cause for hospitalization of cystic fibrosis (CF) patients. These Gram-negative pathogens possess flagella that contain the protein flagellin as a major structural component. Flagellin binds to the host cell glycolipid asialoGM1 (ASGM1), which appears enriched in luminal membranes of respiratory epithelial cells. We demonstrate that in mouse airways, luminal exposure to flagellin leads to inhibition of Na+ absorption by the epithelial Na+ channel ENaC, but does not directly induce a secretory response. Inhibition of ENaC was observed in tracheas of wild-type mice and was attenuated in mice homozygous for the frequent cystic fibrosis conductance regulator (CFTR) mutation G551D. Similar to flagellin, anti-ASGM1 antibody also inhibited ENaC. The inhibitory effects of flagellin on ENaC were attenuated by blockers of the purinergic signaling pathway, although an increase in the intracellular Ca2+ concentration by recombinant or purified flagellin or whole flagella was not observed. Because an inhibitor of the mitogen-activated protein kinase (MAPK) pathway also attenuated the effects of flagellin on Na+ absorption, we conclude that flagellin exclusively inhibits ENaC, probably due to release of ATP and activation of purinergic receptors of the P2Y subtype. Stimulation of these receptors activates the MAPK pathway, thereby leading to inhibition of ENaC. Thus, P. aeruginosa reduces Na+ absorption, which could enhance local mucociliary clearance, a mechanism that seem to be attenuated in CF.
Mesh Headings (Keywords): Adenosine Triphosphate, Amiloride, Animals, Bronchi, Butadienes, Calcium Signaling, Cells, Cultured, Cystic Fibrosis, Egtazic Acid, Epithelial Cells, Epithelial Sodium Channel, Estrenes, Flagellin, G(M1) Ganglioside, Humans, Ion Transport, MAP Kinase Signaling System, Membrane Proteins, Mice, Mice, Inbred C57BL, Mice, Inbred CFTR, Nitriles, Patch-Clamp Techniques, Phosphatidylinositol 4,5-Diphosphate, Pseudomonas Infections, Pseudomonas aeruginosa, Pyrrolidinones, Receptors, Purinergic P2, Respiratory Tract Infections, Sodium, Sodium Channels, Trachea
Check for Full Text / PubMed Unique Identifier (PMID): 16410345
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