Volume 216, Issue 1 p. 112-119
Original Article

Claudin expression in follicle-associated epithelium of rat Peyer's patches defines a major restriction of the paracellular pathway

A. G. Markov

A. G. Markov

Institute of General Physiology, Biological Faculty, St. Petersburg State University, St. Petersburg, Russia

These authors contributed equally to this work.Search for more papers by this author
E. L. Falchuk

E. L. Falchuk

Institute of General Physiology, Biological Faculty, St. Petersburg State University, St. Petersburg, Russia

These authors contributed equally to this work.Search for more papers by this author
N. M. Kruglova

N. M. Kruglova

Institute of General Physiology, Biological Faculty, St. Petersburg State University, St. Petersburg, Russia

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J. Radloff

J. Radloff

Institute of Veterinary Physiology, Freie Universität Berlin, Berlin, Germany

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S. Amasheh

Corresponding Author

S. Amasheh

Institute of Veterinary Physiology, Freie Universität Berlin, Berlin, Germany

Institute of Clinical Physiology, Charité - Universitätsmedizin Berlin, Berlin, Germany

Correspondence: S. Amasheh, Institute of Veterinary Physiology, Oertzenweg 19b, 14163 Berlin, Germany.

E-mail: [email protected]

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First published: 31 July 2015
Citations: 15
See Editorial Commentary: Diener, M. Roadblock for antigens – take a detour via M cells. Acta Physiol 215, 13–14

Abstract

Aim

Members of the tight junction protein family of claudins have been demonstrated to specifically determine paracellular permeability of the intestinal epithelium. In small intestinal mucosa, which is generally considered to be a leaky epithelium, Peyer's patches are a primary part of the immune system. The aim of this study was to analyse the tight junctional barrier of follicle-associated epithelium covering Peyer's patches (lymphoid follicles).

Methods

Employing small intestinal tissue specimens of male Wistar rats, electrophysiological analyses including the Ussing chamber technique, marker flux measurements and one-path impedance spectroscopy were performed. Morphometry of HE-stained tissue sections was taken into account. Claudin expression and localization was analysed by immunoblotting and confocal laser scanning immunofluorescence microscopy.

Results

Almost twofold higher parameters of epithelial and transepithelial tissue resistance and a markedly lower permeability for the paracellular permeability markers 4 and 20 kDa FITC–dextran were detected in follicle-associated epithelium compared to neighbouring villous epithelium. Analysis of claudin expression and localization revealed a stronger expression of major sealing proteins in follicle-associated epithelium, including claudin-1, claudin-4, claudin-5 and claudin-8. Therefore, the specific expression and localization of claudins is in accordance with barrier properties of follicle-associated epithelium vs. neighbouring villous epithelium.

Conclusion

We demonstrate that follicle-associated epithelium is specialized to ensure maximum restriction of the epithelial paracellular pathway in Peyer's patches by selective sealing of tight junctions. This results in an exclusive transcellular pathway of epithelial cells as the limiting and mandatory route for a controlled presentation of antigens to the underlying lymphocytes under physiological conditions.

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