title: Apical junction complex protein expression in the canine colon: differential expression of claudin-2 in the colonic mucosa in dogs with idiopathic colitis.
abstract: Canine idiopathic lymphocytic-plasmacytic colitis (LPC) is a well-recognized clinical and pathological entity in the dog, associated with altered immune cell populations and cytokine expression profiles. Clinical and experimental data indicate that alterations in the permeability of the intestinal epithelium contribute to the pathogenesis of a range of related conditions. The apical junction complex plays a significant role in regulating epithelial paracellular permeability, and we have characterized the distribution of a number of its component tight junction (ZO-1, occludin, claudin-2) and adherens junction (E-cadherin and beta-catenin) proteins in normal colon and colon from dogs with idiopathic LPC. ZO-1, occludin, E-cadherin, and beta-catenin exhibited a distribution in normal canine colon similar to that described previously in humans and rodents. In contrast to the situation in humans, claudin-2-specific labeling was observed in the normal canine colonic crypt epithelium, decreasing in intensity from the distal to the proximal crypt and becoming barely detectable at the luminal surface of the colon. There was little evidence for significant changes in ZO-1, occludin, E-cadherin, or beta-catenin expression in dogs affected by idiopathic LPC. However, claudin-2 expression markedly increased in the proximal crypt and luminal colonic epithelium in affected dogs, suggesting a role in the pathogenesis of canine LPC.
authors.affiliation: Division of Veterinary Clinical Studies, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Veterinary Centre, Midlothian, United Kingdom. Alison.Ridyard@ed.ac.uk
authors.forename: Alison E
authors.initials: AE
authors.lastname: Ridyard
authors.forename: Jeremy K
authors.initials: JK
authors.lastname: Brown
authors.forename: Susan M
authors.initials: SM
authors.lastname: Rhind
authors.forename: Roderick W
authors.initials: RW
authors.lastname: Else
authors.forename: James W
authors.initials: JW
authors.lastname: Simpson
authors.forename: Hugh R P
authors.initials: HR
authors.lastname: Miller
mesh_terms: D022005:Adherens Junctions / Q000378:metabolism*; D000818:Animals; D015820:Cadherins / Q000096:biosynthesis; D003092:Colitis / Q000378:metabolism / Q000662:veterinary*; D003106:Colon / Q000378:metabolism*; D004283:Dog Diseases / Q000378:metabolism*; D004285:Dogs; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000378:metabolism; D008565:Membrane Proteins / Q000096:biosynthesis*; D062793:Occludin; D010750:Phosphoproteins / Q000096:biosynthesis; D019108:Tight Junctions / Q000378:metabolism*; D062826:Zonula Occludens-1 Protein; D051176:beta Catenin / Q000096:biosynthesis
chemical_list: D015820:Cadherins; D008565:Membrane Proteins; C568985:OCLN protein, human; D062793:Occludin; D010750:Phosphoproteins; C569042:TJP1 protein, human; D062826:Zonula Occludens-1 Protein; D051176:beta Catenin