Gut bacteria linked to muscle function in the colon, says mice study

Researchers from Crick University in London and the University of Bern in Switzerland have identified how the contraction and relaxation of muscles in the colon, which is regulated by nerve cells, is influenced by the bacteria in our gut.

The study, published in Nature, when such microbes are present, a specific gene called Ahr is activated in intestinal nerves, resulting in healthy contraction and relaxation of the colon. This relationship can be disrupted in cases of intestinal disorders, like irritable bowel syndrome (IBS).

"There is a clear link between the presence of microbes in the colon and the speed at which food moves through the system. If this relationship goes off-kilter it could cause considerable harm," says Yuuki Obata, lead author and postdoc in the Development and Homeostasis of the Nervous System Laboratory at the Crick.

The study help explain how nerve cells sense the microbes in the gut and how they could coordinate their function with other gut tissues.

"Disturbances of intestinal motility are extremely common and cause a lot of suffering in patients after surgical operations or in conditions such as irritable bowel syndrome," explains Andrew Macpherson, Professor of Medicine and Director of Gastroenterology at the University Hospital of Bern.

"This work provides a foundation to unravel why patients that are colonised with different groups of microbes are susceptible to these intestinal problems." 

Brigitta Stockinger, co-lead author and group leader in the AhRimmunity Laboratory at the Crick, adds: "By drawing on different teams at the Crick and internationally with Bern University, we've combined expertise on the gut and how environmental signals from microbiota and diet are passed to cells, to gain understanding of how gut physiology and digestion are affected by these signals." 

Vassilis Pachnis, co-lead author and group leader in the Development and Homeostasis of the Nervous System Laboratory at the Crick, adds that this is the first study to demonstrate how AhR is used by intestinal nerve cells to sense the presence of microbes and regulate peristalsis therefore promoting healthy digestion.

He adds: "In the future, the use of microbial products that change the activity of AhR in nerve cells could help us alleviate the consequences of abnormal gut peristalsis that is often associated with gastrointestinal diseases."

Source: Nature

Obata, Y., Castaño, Á., Boeing, S. et al. 

"Neuronal programming by microbiota regulates intestinal physiology"

https://doi.org/10.1038/s41586-020-1975-8