Document Detail

Translocation of enteropathogenic Escherichia coli across an in vitro M cell model is regulated by its type III secretion system.
MedLine Citation:
PMID:  17298392     Owner:  NLM     Status:  MEDLINE    
Enteropathogenic Escherichia coli (EPEC) is an extracellular pathogen that utilizes a type III secretion system (TTSS) to modulate diverse host cell processes including cytoskeletal dynamics, tight junction permeability and macrophage phagocytosis. Some EPEC strains exhibit selective tropism for the specialized follicle-associated epithelium (FAE) overlying lymphoid follicles in the gut, which is a major site of uptake of inert particulates and pathogens, but do not translocate from the intestinal lumen in significant numbers. We have investigated the interaction of EPEC with FAE using an established in vitro model of the specialized FAE in which polarized enterocyte-like Caco-2 cells cocultured with the Raji B cell line undergo a phenotypic switch to a form that morphologically and functionally resembles the specialized antigen-transporting M cells found within FAE. Having confirmed that coculture with Raji B cells induces brush border reorganization and enhances particle transport across Caco-2 cells, we investigated translocation of bacteria across the M cell model. While Salmonella translocation was markedly upregulated by Raji coculture, transport of wild-type EPEC occurred at similarly low levels across both native Caco-2 and Caco-2/Raji-cocultured layers. Translocation rates were markedly higher for EPEC strains lacking either functional TTSS or the effector protein EspF. These observations resemble previously reported data on the inhibition of macrophage phagocytosis by EPEC, which has also been reported to be dependent on TTSS and EspF. Furthermore, as with macrophage phagocytosis, enhanced translocation of a TTSS mutant was blocked by wortmannin, implicating inhibition of phosphatidyl inositol 3-kinase-mediated signalling in the regulation of M cell translocation by EPEC.
Isabel Martinez-Argudo; Caroline Sands; Mark A Jepson
Publication Detail:
Type:  Journal Article     Date:  2007-02-09
Journal Detail:
Title:  Cellular microbiology     Volume:  9     ISSN:  1462-5814     ISO Abbreviation:  Cell. Microbiol.     Publication Date:  2007 Jun 
Date Detail:
Created Date:  2007-05-17     Completed Date:  2007-12-12     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100883691     Medline TA:  Cell Microbiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  1538-46     Citation Subset:  IM    
Department of Biochemistry, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, UK.
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MeSH Terms
Androstadienes / pharmacology
Bacterial Translocation*
Caco-2 Cells
Carrier Proteins / metabolism
Cell Line, Tumor
Coculture Techniques
Enterocytes / microbiology*
Epithelial Cells / microbiology*
Escherichia coli / metabolism*,  pathogenicity
Escherichia coli Proteins / metabolism*
Peyer's Patches / cytology*,  microbiology*
Polystyrenes / metabolism
Reg. No./Substance:
0/Androstadienes; 0/Carrier Proteins; 0/Escherichia coli Proteins; 0/EspFU protein, E coli; 0/Polystyrenes; 19545-26-7/wortmannin

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