title: Chymase-mediated intestinal epithelial permeability is regulated by a protease-activating receptor/matrix metalloproteinase-2-dependent mechanism.
abstract: Mast cells regulate intestinal barrier function during disease and homeostasis. Secretion of the mast cell-specific serine protease chymase regulates homeostasis. In the present study, we employ in vitro model systems to delineate the molecular pathways involved in chymase-mediated intestinal epithelial barrier dysfunction. Chymase stimulation of intestinal epithelial (Caco-2 BBe) cell monolayers induced a significant reduction in transepithelial resistance, indicating decreased intestinal epithelial barrier function. The chymase-induced intestinal epithelial barrier dysfunction was characterized by chymase-induced protease-activated receptor (PAR)-2 activation and matrix metalloproteinase (MMP)-2 expression and activation. Consistent with this observation, in vitro analysis revealed chymase-induced PAR-2 activation and increased MAPK activity and MMP-2 expression. Pharmacological and small interfering RNA-mediated antagonism of PAR-2 and MMP-2 significantly attenuated chymase-stimulated barrier dysfunction. Additionally, the chymase/MMP-2-mediated intestinal epithelial dysfunction was associated with a significant reduction in the tight junction protein claudin-5, which was partially restored by MMP-2 inhibition. Finally, incubation of Caco-2 BBe cells with chymase-sufficient, but not chymase-deficient, bone marrow-derived mast cells decreased barrier function, which was attenuated by the chymase inhibitor chymostatin. Collectively, these results suggest that mast cell/chymase-mediated intestinal epithelial barrier function is mediated by PAR-2/MMP-2-dependent pathways.
authors.affiliation: Division of Allergy and Immunology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA.
authors.forename: Katherine R
authors.initials: KR
authors.lastname: Groschwitz
authors.forename: David
authors.initials: D
authors.lastname: Wu
authors.forename: Heather
authors.initials: H
authors.lastname: Osterfeld
authors.forename: Richard
authors.initials: R
authors.lastname: Ahrens
authors.forename: Simon P
authors.initials: SP
authors.lastname: Hogan
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000201:enzymology / Q000502:physiology; D018938:Caco-2 Cells; D053818:Chymases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D062507:Claudin-5 / Q000502:physiology; D005455:Fluorescent Antibody Technique; D006801:Humans; D007413:Intestinal Mucosa / Q000201:enzymology* / Q000502:physiology*; D016086:Lentivirus / Q000235:genetics; D008407:Mast Cells / Q000502:physiology; D020778:Matrix Metalloproteinase 2 / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010539:Permeability; D044464:Receptor, PAR-2 / Q000502:physiology*; D019108:Tight Junctions / Q000502:physiology; D014161:Transduction, Genetic
chemical_list: D062507:Claudin-5; D044464:Receptor, PAR-2; D053818:Chymases; D020778:Matrix Metalloproteinase 2