Previous Article | Next Article ![]()
Infection and Immunity, March 2001, p. 1329-1336, Vol. 69, No. 3
Epithelial Pathobiology Research Unit,
Department of Pathology, Emory University School of Medicine,
Atlanta, Georgia1; Institut fur
Medizinische Mikrobiologie und Hygiene, Universität Mainz,
Mainz,2 Cell Biology and Biophysics
Program, EMBL, Heidelberg,3 and Max
Planck Institute of Molecular Cell Biology and Genetics,
Dresden,4 Germany; and Department of
Pathology, Wayne State University, Detroit, Michigan5
Received 28 July 2000/Returned for modification 14 September
2000/Accepted 20 November 2000
The anaerobic bacterium Clostridium difficile is the
etiologic agent of pseudomembranous colitis. C. difficile
toxins TcdA and TcdB are UDP-glucosyltransferases that monoglucosylate
and thereby inactivate the Rho family of GTPases (W. P. Ciesla,
Jr., and D. A. Bobak, J. Biol. Chem. 273:16021-16026, 1998).
We utilized purified reference toxins of C. difficile,
TcdA-10463 (TcdA) and TcdB-10463 (TcdB), and a model intestinal
epithelial cell line to characterize their influence on tight-junction
(TJ) organization and hence to analyze the mechanisms by which they
contribute to the enhanced paracellular permeability and disease
pathophysiology of pseudomembranous colitis. The increase in
paracellular permeability induced by TcdA and TcdB was associated with
disorganization of apical and basal F-actin. F-actin restructuring was
paralleled by dissociation of occludin, ZO-1, and ZO-2 from the lateral
TJ membrane without influencing the subjacent adherens junction
protein, E-cadherin. In addition, we observed decreased association of actin with the TJ cytoplasmic plaque protein ZO-1. Differential detergent extraction and fractionation in sucrose density gradients revealed TcdB-induced redistribution of occludin and ZO-1 from detergent-insoluble fractions constituting "raft-like" membrane microdomains, suggesting an important role of Rho proteins in maintaining the association of TJ proteins with such microdomains. These toxin-mediated effects on actin and TJ structure provide a
mechanism for early events in the pathophysiology of pseudomembranous colitis.
0019-9567/01/$04.00+0 DOI: 10.1128/IAI.69.3.1329-1336.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
Clostridium difficile Toxins Disrupt
Epithelial Barrier Function by Altering Membrane Microdomain
Localization of Tight Junction Proteins
*
Corresponding author. Mailing address: Department of
Pathology and Laboratory Medicine, Emory University, WMRB 2335, 1639 Pierce Dr., Atlanta, GA 30322. Phone: (404) 727-8543. Fax: (404) 727-3321. E-mail: anusrat{at}emory.edu.
This article has been cited by other articles:
| J. Bacteriol. | J. Virol. | Eukaryot. Cell |
|---|
| Microbiol. Mol. Biol. Rev. | Clin. Vaccine Immunol. | All ASM Journals |
|---|