title: Neutrophil-mediated epithelial injury during transmigration: role of elastase.
abstract: Neutrophil-mediated injury to gut epithelium may lead to disruption of the epithelial barrier function with consequent organ dysfunction, but the mechanisms of this are incompletely characterized. Because the epithelial apical junctional complex, comprised of tight and adherens junctions, is responsible in part for this barrier function, we investigated the effects of neutrophil transmigration on these structures. Using a colonic epithelial cell line, we observed that neutrophils migrating across cell monolayers formed clusters that were associated with focal epithelial cell loss and the creation of circular defects within the monolayer. The loss of epithelial cells was partly attributable to neutrophil-derived proteases, likely elastase, because it was prevented by elastase inhibitors. Spatially delimited disruption of epithelial junctional complexes with focal loss of E-cadherin, beta-catenin, and zonula occludens 1 was observed adjacent to clusters of transmigrating neutrophils. During neutrophil transmigration, fragments of E-cadherin were released into the apical supernatant, and inhibitors of neutrophil elastase prevented this proteolytic degradation. Addition of purified leukocyte elastase also resulted in release of E-cadherin fragments, but only after opening of tight junctions. Taken together, these data demonstrate that neutrophil-derived proteases can mediate spatially delimited disruption of epithelial apical junctions during transmigration. These processes may contribute to epithelial loss and disruption of epithelial barrier function in inflammatory diseases.
authors.affiliation: Department of Pediatrics, Division of Gastroenterology and Nutrition, The University of Toronto, Toronto, Ontario, Canada M5S 1A8.
authors.forename: H H
authors.initials: HH
authors.lastname: Ginzberg
authors.forename: V
authors.initials: V
authors.lastname: Cherapanov
authors.forename: Q
authors.initials: Q
authors.lastname: Dong
authors.forename: A
authors.initials: A
authors.lastname: Cantin
authors.forename: C A
authors.initials: CA
authors.lastname: McCulloch
authors.forename: P T
authors.initials: PT
authors.lastname: Shannon
authors.forename: G P
authors.initials: GP
authors.lastname: Downey
mesh_terms: D022005:Adherens Junctions / Q000378:metabolism; D015820:Cadherins / Q000378:metabolism; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology*; D002633:Chemotaxis / Q000187:drug effects / Q000502:physiology; D003106:Colon; D003598:Cytoskeletal Proteins / Q000378:metabolism; D017097:Electric Impedance; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D005110:Extracellular Space / Q000502:physiology; D006801:Humans; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D009504:Neutrophils / Q000166:cytology* / Q000201:enzymology*; D010196:Pancreatic Elastase / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000494:pharmacology; D009195:Peroxidase / Q000378:metabolism / Q000494:pharmacology; D010750:Phosphoproteins / Q000378:metabolism; D011480:Protease Inhibitors / Q000494:pharmacology; D019108:Tight Junctions / Q000378:metabolism; D015534:Trans-Activators; D062826:Zonula Occludens-1 Protein; D051176:beta Catenin
chemical_list: C495270:CTNNB1 protein, human; D015820:Cadherins; D003598:Cytoskeletal Proteins; D008565:Membrane Proteins; D010750:Phosphoproteins; D011480:Protease Inhibitors; C569042:TJP1 protein, human; D015534:Trans-Activators; D062826:Zonula Occludens-1 Protein; D051176:beta Catenin; D009195:Peroxidase; D010196:Pancreatic Elastase