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Updated: Mar 31, 2026
In Vitro and In Vivo Approaches to Determine Intestinal Epithelial Cell Permeability
Published on: October 19, 2018
Matrix metalloproteinase 9-induced increase in intestinal epithelial tight junction permeability contributes to the
Prashant Nighot1, Rana Al-Sadi1, Manmeet Rawat2
1Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, New Mexico;
Abstract:
Recent studies have implicated a pathogenic role for matrix metalloproteinases 9 (MMP-9) in inflammatory bowel disease. Although loss of epithelial barrier function has been shown to be a key pathogenic factor for the development of intestinal inflammation, the role of MMP-9 in intestinal barrier function remains unclear. The aim of this study was to investigate the role of MMP-9 in intestinal barrier function and intestinal inflammation. Wild-type (WT) and MMP-9(-/-) mice were subjected to experimental dextran sodium sulfate (DSS) colitis by administration of 3% DSS in drinking water for 7 days. The mouse colonic permeability was measured in vivo by recycling perfusion of the entire colon using fluorescently labeled dextran. The DSS-induced increase in the colonic permeability was accompanied by an increase in intestinal epithelial cell MMP-9 expression in WT mice. The DSS-induced increase in intestinal permeability and the severity of DSS colitis was found to be attenuated in MMP-9(-/-) mice. The colonic protein expression of myosin light chain kinase (MLCK) and phospho-MLC was found to be significantly increased after DSS administration in WT mice but not in MMP-9(-/-) mice. The DSS-induced increase in colonic permeability and colonic inflammation was attenuated in MLCK(-/-) mice and MLCK inhibitor ML-7-treated WT mice. The DSS-induced increase in colonic surface epithelial cell MLCK mRNA was abolished in MMP-9(-/-) mice. Lastly, increased MMP-9 protein expression was detected within the colonic surface epithelial cells in ulcerative colitis cases. These data suggest a role of MMP-9 in modulation of colonic epithelial permeability and inflammation via MLCK.
Insights
Matrix metalloproteinases 9 (MMP-9) exacerbates inflammatory bowel disease by increasing intestinal permeability. Inhibiting MMP-9 or myosin light chain kinase (MLCK) reduces colitis severity, suggesting MMP-9 influences barrier function via MLCK.
Area of Science:
- Gastroenterology
- Immunology
- Molecular Biology
Background:
- Inflammatory bowel disease (IBD) involves epithelial barrier dysfunction.
- Matrix metalloproteinases 9 (MMP-9) is implicated in IBD pathogenesis.
- The specific role of MMP-9 in intestinal barrier integrity is not fully understood.
Purpose of the Study:
- To investigate the role of MMP-9 in intestinal barrier function.
- To elucidate the mechanism by which MMP-9 affects intestinal inflammation.
Main Methods:
- Experimental dextran sodium sulfate (DSS) colitis was induced in wild-type (WT) and MMP-9 knockout (MMP-9(-/-)) mice.
- Colonic permeability was assessed using fluorescently labeled dextran.
- Expression of MMP-9, myosin light chain kinase (MLCK), and phospho-MLC was analyzed.
- Ulcerative colitis patient samples were examined for MMP-9 expression.
Main Results:
- DSS-induced increases in colonic permeability and colitis severity were attenuated in MMP-9(-/-) mice.
- MMP-9 deficiency prevented DSS-induced increases in colonic MLCK and phospho-MLC.
- Inhibition of MLCK also reduced DSS-induced colonic permeability and inflammation.
- DSS-induced MLCK mRNA expression in colonic epithelial cells was abolished in MMP-9(-/-) mice.
- Increased MMP-9 expression was observed in the colonic epithelium of ulcerative colitis patients.
Conclusions:
- MMP-9 plays a pathogenic role in DSS-induced colitis.
- MMP-9 contributes to increased intestinal permeability and inflammation, potentially via modulation of MLCK.
- Targeting MMP-9 or MLCK may represent therapeutic strategies for IBD.
