[PDF][PDF] Normalization of host intestinal mucus layers requires long-term microbial colonization

MEV Johansson, HE Jakobsson, J Holmén-Larsson… - Cell host & …, 2015 - cell.com
MEV Johansson, HE Jakobsson, J Holmén-Larsson, A Schütte, A Ermund…
Cell host & microbe, 2015cell.com
The intestinal mucus layer provides a barrier limiting bacterial contact with the underlying
epithelium. Mucus structure is shaped by intestinal location and the microbiota. To
understand how commensals modulate gut mucus, we examined mucus properties under
germ-free (GF) conditions and during microbial colonization. Although the colon mucus
organization of GF mice was similar to that of conventionally raised (Convr) mice, the GF
inner mucus layer was penetrable to bacteria-sized beads. During colonization, in which GF …
Summary
The intestinal mucus layer provides a barrier limiting bacterial contact with the underlying epithelium. Mucus structure is shaped by intestinal location and the microbiota. To understand how commensals modulate gut mucus, we examined mucus properties under germ-free (GF) conditions and during microbial colonization. Although the colon mucus organization of GF mice was similar to that of conventionally raised (Convr) mice, the GF inner mucus layer was penetrable to bacteria-sized beads. During colonization, in which GF mice were gavaged with Convr microbiota, the small intestine mucus required 5 weeks to be normally detached and colonic inner mucus 6 weeks to become impenetrable. The composition of the small intestinal microbiota during colonization was similar to Convr donors until 3 weeks, when Bacteroides increased, Firmicutes decreased, and segmented filamentous bacteria became undetectable. These findings highlight the dynamics of mucus layer development and indicate that studies of mature microbe-mucus interactions should be conducted weeks after colonization.
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