title: Constitutive expression of MMP9 in intestinal epithelium worsens murine acute colitis and is associated with increased levels of proinflammatory cytokine Kc.
abstract: Inflammatory bowel disease (IBD), which includes ulcerative colitis and Crohn's disease, is a chronic inflammatory disease associated with an increased risk for colon cancer. Matrix metalloproteinases (MMPs) are the predominant proteinases expressed in the gut mucosa during active IBD. Our laboratory has previously demonstrated that epithelial-derived MMP9 is absent in normal colonic tissue but is upregulated during IBD. In this study MMP9 transgenic mice (Tg-villin-MMP9) are generated specifically to overexpress MMP9 in intestinal epithelium to examine the role and underlying mechanism by which it modulates the pathogenesis of acute colitis. Dextran sodium sulfate (3% DSS)- and Salmonella typhimurium (S.T.)-induced colitis models were used to study gut inflammation in Tg-villin-MMP9 and wild-type littermates (WT). Colonic tissue was analyzed via Western blot, histology, myeloperoxidase (MPO) assay, and quantitative PCR. Tg-villin-MMP9 mice expressed significantly increased MMP9 mRNA and protein expression at basal level. There was a significant decrease in the goblet cells, but a significant increase in proliferation and apoptosis were observed among Tg-villin-MMP9 mice compared with WT mice. There was also a significant increase in the proinflammatory chemokine Kc among Tg-villin-MMP9 compared with WT mice. Tg-villin-MMP9 exhibited a severe inflammatory response than WT mice in both DSS- and S.T.-induced colitis models as evident by greater weight loss and higher clinical score, histological score, and MPO activity, which correlated with relative levels of Kc mRNA. MMP9 expressed by intestinal epithelial cells mediates inflammation in colitis with simultaneous increase in proinflammatory cytokine Kc.
authors.affiliation: Center for Diagnostics and Therapeutics, Department of Biology, Georgia State University, Atlanta, GA 30303, USA.
authors.forename: Hongchun
authors.initials: H
authors.lastname: Liu
authors.forename: Neal R
authors.initials: NR
authors.lastname: Patel
authors.forename: Lewins
authors.initials: L
authors.lastname: Walter
authors.forename: Sarah
authors.initials: S
authors.lastname: Ingersoll
authors.forename: Shanthi V
authors.initials: SV
authors.lastname: Sitaraman
authors.forename: Pallavi
authors.initials: P
authors.lastname: Garg
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D054360:Chemokine CXCL1 / Q000378:metabolism*; D003092:Colitis / Q000139:chemically induced / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology; D003106:Colon / Q000473:pathology; D016264:Dextran Sulfate; D004195:Disease Models, Animal; D045325:HCT116 Cells; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000503:physiopathology; D007413:Intestinal Mucosa / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis*; D051379:Mice; D008822:Mice, Transgenic; D012481:Salmonella Infections, Animal / Q000473:pathology / Q000503:physiopathology; D012486:Salmonella typhimurium
chemical_list: D054360:Chemokine CXCL1; C475895:Cxcl1 protein, mouse; D016264:Dextran Sulfate; D020780:Matrix Metalloproteinase 9
keywords: IL-8; dextran sodium sulfate; inflammation; transgenic mice