Review
Copyright ©2011 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastrointest Pathophysiol. Dec 15, 2011; 2(6): 123-137
Published online Dec 15, 2011. doi: 10.4291/wjgp.v2.i6.123
Enterocytes’ tight junctions: From molecules to diseases
Stelios F Assimakopoulos, Ismini Papageorgiou, Aristidis Charonis
Stelios F Assimakopoulos, Department of Internal Medicine, University Hospital of Patras, Patras 26504, Greece
Ismini Papageorgiou, Institute of Physiology and Pathophysiology, Ruprecht-Karls University of Heidelberg, 69120 Heidelberg, Germany
Aristidis Charonis, Biomedical Research Foundation of the Academy of Athens, Athens 11527, Greece
Author contributions: Assimakopoulos SF and Papageorgiou I wrote this review; Charonis A critically reviewed the manuscript.
Correspondence to: Stelios F Assimakopoulos, MD, PhD, Department of Internal Medicine, University Hospital of Patras, Patras 26504, Greece. sassim@upatras.gr
Telephone: +30-2610-999583 Fax: +30-2610-999582
Received: July 7, 2011
Revised: August 26, 2011
Accepted: October 31, 2011
Published online: December 15, 2011
Abstract

Tight junctions (TJs) are structures between cells where cells appear in the closest possible contact. They are responsible for sealing compartments when epithelial sheets are generated. They regulate the permeability of ions, (macro) molecules and cells via the paracellular pathway. Their structure at the electron microscopic level has been well known since the 1970s; however, only recently has their macromolecular composition been revealed. This review first examines the major macromolecular components of the TJs (occludin, claudins, junctional adhesion molecule and tricellulin) and then the associated macromolecules at the intracellular plaque [zonula occludens (ZO)-1, ZO-2, ZO-3, AF-6, cingulin, 7H6]. Emphasis is given to their interactions in order to begin to understand the mode of assembly of TJs. The functional significance of TJs is detailed and several mechanisms and factors involved are discussed briefly. Emphasis is given to the role of intestinal TJs and the alterations observed or speculated in diverse disease states. Specifically, intestinal TJs may exert a pathogenetic role in intestinal (inflammatory bowel disease, celiac disease) and extraintestinal diseases (diabetes type 1, food allergies, autoimmune diseases). Additionally, intestinal TJs may be secondarily disrupted during the course of diverse diseases, subsequently allowing the bacterial translocation phenomenon and promoting the systemic inflammatory response, which is often associated with clinical deterioration. The major questions in the field are highlighted.

Keywords: Tight junctions; Occludin; Claudins; Junctional adhesion molecule; Tricellulin; Intestinal permeability