Tiny pieces of genetic material known as microRNAs do a big job: They control gene activity inside bacteria in the intestines, a new study finds. The little RNAs also control the mix of microbes living in the gut.
Those functions help keep the intestines healthy, researchers report January 13 in Cell Host & Microbe. If the findings hold up, microRNAs may become a tool for shaping the composition of the body’s microbes, or microbiome.
Cells lining the colons of both humans and mice pump out microRNAs, Shirong Liu, an immunologist at Brigham and Women’s Hospital in Boston, and colleagues discovered. Those microRNAs can slip inside bacteria to control activity of specific genes, the team found in research with mice. Dialing gene activity up or down could stimulate or suppress growth of certain bacteria.
Mice that couldn’t produce microRNAs in their colons were more prone to develop colitis, an inflammation of the colon’s lining. When researchers gave the microRNA-deficient mice infusions of normal microRNA mixes, the rodents had less severe symptoms. Those results suggest that humans and mice use microRNAs to control bacteria and keep their colons healthy.