Gut microbes are well known to contribute to health and disease, but what has been less clear is how the host controls gut microbes. A study published January 13 in Cell Host & Microbe now reveals that mice and humans produce small molecules (microRNAs) from their GI tract, which are shed in feces, to regulate the composition of gut microbes and thereby protect against intestinal diseases such as colitis.
“Since gut microbes play an important role in host metabolism and immunity as well as in disease, it is important to understand the mechanisms by which the microbiota is regulated by the host and to identify ways in which to manipulate the microbiome,” says senior study author Howard Weiner. “Our findings reveal a host defense mechanism and highlight microRNAs as a strategy for manipulation of the microbiome for the health of the host.