The two mucus layers of colon are organized by the MUC2 mucin, whereas the outer layer is a legislator of host–microbial interactions

Proceedings of the National Academy of Sciences of the United States of America - Tập 108 Số supplement_1 - Trang 4659-4665 - 2011
Malin Johansson1,2, Jessica M. Holmén Larsson1,2, Gunnar C. Hansson1,2
1Department of Medical Biochemistry, University of Gothenburg, 405 30 Gothenburg, Sweden
2Washington University School of Medicine, St. Louis, MO

Tóm tắt

The normal intestinal microbiota inhabits the colon mucus without triggering an inflammatory response. The reason for this and how the intestinal mucus of the colon is organized have begun to be unraveled. The mucus is organized in two layers: an inner, stratified mucus layer that is firmly adherent to the epithelial cells and approximately 50 μm thick; and an outer, nonattached layer that is usually approximately 100 μm thick as measured in mouse. These mucus layers are organized around the highly glycosylated MUC2 mucin, forming a large, net-like polymer that is secreted by the goblet cells. The inner mucus layer is dense and does not allow bacteria to penetrate, thus keeping the epithelial cell surface free from bacteria. The inner mucus layer is converted into the outer layer, which is the habitat of the commensal flora. The outer mucus layer has an expanded volume due to proteolytic activities provided by the host but probably also caused by commensal bacterial proteases and glycosidases. The numerous O -glycans on the MUC2 mucin not only serve as nutrients for the bacteria but also as attachment sites and, as such, probably contribute to the selection of the species-specific colon flora. This observation that normal human individuals carry a uniform MUC2 mucin glycan array in colon may indicate such a specific selection.

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Proceedings of the National Academy of Sciences of the United States of America

Tập 108 Số supplement_1

4659-4665

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