In recent years, it has been pointed out that microbial metabolites such as short-chain fatty acids affect host immune responses that maintain intestinal homeostasis, and that their dysregulation leads to disease.In particular, propionic acid, a type of short-chain fatty acid, is a major microbial fermentation metabolite in the intestines of many animals, including humans, and it is becoming clear that it has various health-promoting effects not only on the intestine but also on the whole body.

　The joint research group focused on this propionic acid.We investigated how propionic acid intake by mother mice during lactation contributes to allergic airway inflammation in offspring.As a result, it was found that allergic airway inflammation was suppressed via GPR41, a G protein-coupled receptor that transduces intracellular extracellular signals on the cell membrane.

　Children who developed bronchial asthma in human birth cohorts (groups of people born within a certain period of time) also had lower faecal propionate concentrations at 1 month of age.Analysis suggested that three genera of intestinal bacteria (Varibaculum, Bifidobacterium, and Parabacteroides) may be involved in the production of fecal propionic acid.

　The present results indicate that short-chain fatty acids, which are known to be produced by specific intestinal bacteria, are deeply involved in not only intestinal diseases but also extraintestinal diseases such as allergic diseases.In the future, it is expected to contribute to the development of new treatments for allergic diseases including bronchial asthma that target intestinal bacteria and short-chain fatty acids.

Paper information:[Gut Microbes] The propionate-GPR41 axis in infancy protects from subsequent bronchial asthma onset