The mammalian gut is home to a tremendous number of microorganisms, termed the gut microbiota. This peaceful community helps to digest complex carbohydrate, such as dietary fibers, and provides the body with important nutrients and other molecules. At the same time, however, this bacterial community may become a danger to the body when it is not safely contained in the intestine. Thus, to separate the gut bacterial community from the body, the intestinal surface is covered with a mucus layer, which as a physical barrier that keeps the gut bacteria at a good distance from the gut wall.
Defects in the mucus layer have been observed in mice that were fed a diet that lacked dietary fibers, and it is thought that under these dietary conditions the gut microbiota start chewing on the mucus shield, which is also a carbohydrate-rich source. The study of Schröder et al., however, shows that mucus defects can occur even under a fiber-rich diet. By using a unique measurement system, they found that genetically obese mice, which over-eat this fiber-rich diet, have a defective colonic mucus layer with increased mucus penetrability and a strongly reduced “mucus growth rate”. Their data suggest that the gut microbiota community of obese mice may cause these colonic mucus defects, even in the presence of dietary fiber. Yet, it is so far unknown whether the gut microbiota may have similar effects in obese humans as well.
Picture: Björn O. Schröder, by Chris Coe
Illustration by Björn O. Schröder
Bjoern O. Schroeder, George M. H. Birchenough, Meenakshi Pradhan, Elisabeth E. L. Nyström, Marcus Henricsson, Gunnar C. Hansson and Fredrik Bäckhed (2020) Obesity-associated microbiota contributes to mucus layer defects in genetically obese mice. Journal of Biological Chemistry
You can read the full article here. J. Biol. Chem. jbc.RA120.015771. doi:10.1074/jbc.RA120.015771
About the author
Björn and his lab focuses on host-microbe interaction in the intestine: gut microbiota and intestinal mucosal barrier function. They use a combination of gut microbiota analyses, microbiota transplantations (FMT), state-of-the-art ex vivo mucus measurements, antimicrobial assays, as well as different microscopy techniques.
Lab website: https://mucubacter.org/