TY - JOUR
AU - Garg, Pallavi
AB - Background Inflammatory Bowel Disease (IBD) including ulcerative colitis and Crohn's Disease, is a chronic inflammatory disease that affects the entire gastrointestinal tract particularly the colonic mucosa and is associated with an increased risk of colon cancer. Matrix metalloproteinases (MMPs) are the Zn2+ dependent proteinases expressed in the gut mucosa during the course of active IBD. Of the MMPs, MMP9 is the predominant MMP highly expressed in IBD but absent in normal colonic tissues. In the present study, we used MMP9 transgenic mice (Tg-villin-MMP9) that specifically overexpress MMP9 in the colonic epithelium to investigate the mechanism by which it mediates inflammation in acute colitis. Methods Age and gender matched Tg-villin-MMP9 and their wild type littermates (WT) mice were used for in vivo experiments and stably transfected HCT116 colonic epithelium cell line overexpressing MMP-9 was used for in vitro experiments. Barrier function was performed by 4kD FITC -dextran and Swiss rolls were used for Alcian blue (AB-PAS) staining. Organ culture ELISA was used to measure protein levels of Kc. Dextran sodium sulfate (3% DSS) and Salmonella typhimurium (S. T.) were used to induce colitis. Colonic tissues after induction of acute colitis were histologically examined and extracts were analyzed by western blotting, myeloperoxidase (MPO) assay and Q-PCR. Results At the basal level mRNA level and the protein expression of MMP9 were significantly higher (12±0.52-fold and 5.7±0.06-fold respectively) in Tg-villin-MMP9 mice than in WT mice. Tg-villin-MMP9 mice showed significant increase (3.16±0.82) in permeability compared to WT littermates (1.07±0.16). AB-PAS staining revealed a significant decrease in goblet cell numbers in Tg-villin-MMP9 mice compared to WT mice. At the basal level, Q-PCR indicated a significant increase (5.7±1.25-fold) in the level of pro-inflammatory chemokine Kc mRNAs (human homologue is IL-8) in Tg-villin-MMP9 compared to WT mice. Organ culture ELISA showed significantly increased expression of Kc protein levels among Tg-villin-MMP9 mice (2.61±0.18) compared to WT mice (1.28±0.25). This result was also supported by in vitro model. Stably transfected HCT116 colonic epithelium cell line over-expressing MMP9 exhibited a significant increase in IL-8 protein levels (3.3±0.56) compared to vector (1.46±0.14). Tg-villin-MMP9 mice exposed to DSS- and S. T.-induced colitis exhibited a significant loss of body weight and higher mortality. Tg-villin-MMP9 mice exposed to DSS- induced colitis exhibited significantly higher clinical score (9.5±0.5) compared to WT littermates (6.5±0.6). Tg-villin-MMP9 mice undergoing DSS- and S. T.-induced colitis showed significantly higher histological scores (7.2±0.5 and 7.8±0.6 respectively) and increased MPO activity (1.9±0.7 MPO U/mg protein and 2.4±0.4) compared to WT animals (3.6±0.8 and 3.2±0.5; and 0.7±0.2 MPO U/mg protein and 0.6±0.4 respectively). Further, the level of mRNA encoding Kc was also significantly higher (9.0±10.5-fold) in Tg-villin-MMP9 mice undergoing DSS-induced colitis, and also in mice undergoing S. T.-induced colitis (7.8±9.6-fold), compared to the levels in WT littermates. Conclusion(s) Together, the data show that constitutive expression of MMP9 in colonic epithelium causes spontaneous inflammation associated with permeability defect and an increase in the levels of pro-inflammatory chemokine Kc. Results acquired from the study may help in modifying the therapeutic strategy as the treatment of acute colitis. Copyright © 2012 Crohn's & Colitis Foundation of America, Inc.
TI - P-201 Overexpression of MMP9 in Colonic Epithelium Is Associated With Defective Permeability and Increased Levels of Pro-Inflammatory-Chemokine Kc, in Acute Colitis
JF - Inflammatory Bowel Diseases
DO - 10.1097/00054725-201212001-00234
DA - 2012-12-01
UR - https://www.deepdyve.com/lp/oxford-university-press/p-201-overexpression-of-mmp9-in-colonic-epithelium-is-associated-with-0oj4xoHJ8L
SP - S94
EP - S95
VL - 18
IS - suppl_1
DP - DeepDyve
ER -