title: Essential role for mast cell tryptase in acute experimental colitis.
abstract: Patients with inflammatory bowel disease (IBD) have increased numbers of human tryptase-β (hTryptase-β)-positive mast cells (MCs) in the gastrointestinal tract. The amino acid sequence of mouse mast cell protease (mMCP)-6 is most similar to that of hTryptase-β. We therefore hypothesized that this mMCP, or the related tryptase mMCP-7, might have a prominent proinflammatory role in experimental colitis. The dextran sodium sulfate (DSS) and trinitrobenzene sulfonic acid (TNBS) colitis models were used to evaluate the differences between C57BL/6 (B6) mouse lines that differ in their expression of mMCP-6 and mMCP-7 with regard to weight loss, colon histopathology, and endoscopy scores. Microarray analyses were performed, and confirmatory real-time PCR, ELISA, and/or immunohistochemical analyses were carried out on a number of differentially expressed cytokines, chemokines, and matrix metalloproteinases (MMPs). The mMCP-6-null mice that had been exposed to DSS had significantly less weight loss as well as significantly lower pathology and endoscopy scores than similarly treated mMCP-6-expressing mice. This difference in colitis severity was confirmed endoscopically in the TNBS-treated mice. Evaluation of the distal colon segments revealed that numerous proinflammatory cytokines, chemokines that preferentially attract neutrophils, and MMPs that participate in the remodeling of the ECM were all markedly increased in the colons of DSS-treated WT mice relative to untreated WT mice and DSS-treated mMCP-6-null mice. Collectively, our data show that mMCP-6 (but not mMCP-7) is an essential MC-restricted mediator in chemically induced colitis and that this tryptase acts upstream of many of the factors implicated in IBD.
authors.affiliation: Department of Medicine, Harvard Medical School, Boston, MA 02115, USA. mjhamilton@partners.org
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Hamilton
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Sinnamon
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Lyng
authors.forename: Jonathan N
authors.initials: JN
authors.lastname: Glickman
authors.forename: Xueli
authors.initials: X
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Xing
authors.forename: Steven A
authors.initials: SA
authors.lastname: Krilis
authors.forename: Richard S
authors.initials: RS
authors.lastname: Blumberg
authors.forename: Roberto
authors.initials: R
authors.lastname: Adachi
authors.forename: David M
authors.initials: DM
authors.lastname: Lee
authors.forename: Richard L
authors.initials: RL
authors.lastname: Stevens
mesh_terms: D000818:Animals; D018925:Chemokines / Q000276:immunology; D003106:Colon / Q000378:metabolism / Q000473:pathology; D016207:Cytokines / Q000276:immunology; D016264:Dextran Sulfate / Q000633:toxicity; D004797:Enzyme-Linked Immunosorbent Assay; D007150:Immunohistochemistry; D015212:Inflammatory Bowel Diseases / Q000139:chemically induced / Q000201:enzymology / Q000276:immunology* / Q000473:pathology; D008407:Mast Cells / Q000276:immunology* / Q000378:metabolism; D020782:Matrix Metalloproteinases / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D046228:Microarray Analysis; D016133:Polymerase Chain Reaction; D014302:Trinitrobenzenesulfonic Acid / Q000633:toxicity; D053802:Tryptases / Q000276:immunology* / Q000378:metabolism
chemical_list: D018925:Chemokines; D016207:Cytokines; C509190:Tpsb2 protein, mouse; D014302:Trinitrobenzenesulfonic Acid; D016264:Dextran Sulfate; D053802:Tryptases; D020782:Matrix Metalloproteinases