Paracellular permeability is increased by basal lipopolysaccharide in a primary culture of colonic epithelial cells; an effect prevented by an activator of Toll-like receptor-2


Lipopolysaccharide (LPS), which generally activates Toll-like receptor 4 (TLR4), is expressed on commensal colonic bacteria. In a number of tissues, LPS can act directly on epithelial cells to increase paracellular permeability. Such an effect in the colon would have an important impact on the understanding of normal homeostasis and of pathology. Our aim was to use a novel primary culture of colonic epithelial cells grown on Transwells to investigate whether LPS, or Pam(3)CSK( 4), an activator of TLR2, affected paracellular permeability. Consequently, [(14)C]-mannitol transfer and transepithelial electrical resistance (TEER) were measured. The preparation consisted primarily of cytokeratin-18 positive epithelial cells that produced superoxide, stained for mucus with periodic acid-Schiff reagent, exhibited alkaline phosphatase activity and expressed TLR2 and TLR4. Tight junctions and desmosomes were visible by transmission electron microscopy. Basally, but not apically, applied LPS from Escherichia coli increased the permeability to mannitol and to a 10-kDa dextran, and reduced TEER. The LPS from Helicobacter pylori increased paracellular permeability of gastric cells when applied either apically or basally, in contrast to colon cells, where this LPS was active only from the basal aspect. A pan-caspase inhibitor prevented the increase in caspase activity caused by basal E. coli LPS, and reduced the effects of LPS on paracellular permeability. Synthetic Pam(3)CSK(4) in the basal compartment prevented all effects of basal E. coli LPS. In conclusion, LPS applied to the base of the colonic epithelial cells increased paracellular permeability by a mechanism involving caspase activation, suggesting a process by which perturbation of the gut barrier could be exacerbated. Moreover, activation of TLR2 ameliorated such effects.

Publication DOI:
Divisions: College of Health & Life Sciences
College of Health & Life Sciences > Chronic and Communicable Conditions
College of Health & Life Sciences > School of Biosciences
College of Health & Life Sciences > School of Biosciences > Cellular and Molecular Biomedicine
Uncontrolled Keywords: animals,caco-2 cells,cell culture techniques,cell membrane permeability,cell polarity,colon,enterocytes,epithelial cells,escherichia coli,guinea pigs,helicobacter pylori,humans,lipopeptides,lipopolysaccharides,mannitol,species specificity,toll-like receptor 2,Cell Biology,Molecular Biology,Immunology,Microbiology,Infectious Diseases
Publication ISSN: 1743-2839
Last Modified: 03 Jan 2024 18:59
Date Deposited: 10 Jul 2012 11:32
Full Text Link: http://ini.sage ... ontent/17/3/269
Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
PURE Output Type: Article
Published Date: 2011-06
Published Online Date: 2010-05-14
Authors: Hanson, Peter J. (ORCID Profile 0000-0001-6905-6051)
Moran, Anthony P.
Butler, Kate



Version: Draft Version

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