Korin Albert, PhD student in the Sela Lab (UMass Amherst)
September 1, 2015
Many studies are showing that an individual’s microbiome influences gastrointestinal health. The impact, however, of commensal microbes on most other body systems is still emerging. Recently, there have been several discoveries linking the microbiome and the nervous system.
In a paper recently by Erny et al. investigated modulation of microglia by the microbiome. Microglia are the immune cells of the central nervous system, protecting the brain and maintaining healthy neural circuitry. People with microglial deficiencies are susceptible to neurological and neuropsychiatric diseases.
To understand the influence of the microbiome on microglia, the researchers compared mice that had a normal microbiome to special germ-free (GF) mice that are raised without any microbes. Interestingly, several genes important for cell growth and proliferation were turned on in the microglia of GF mice. Examination of the brains of the GF mice showed an increase in a specific type of microglia cell that could lead to inflammation. However, GF mice had normal brain tissue when fed short chain fatty acids normally produced by gut microbes. When the scientists examined the microglia structure they observed anatomical differences between microglia from GF mice versus those from normal mice. Finally, microglia from GF mice are incapable of mounting the appropriate attack against a virus that typically infects neural tissue.
This paper is interesting as it describes a previously unknown interaction of the human microbiome with the both the immune and nervous systems.
Erny, Daniel, et al. “Host microbiota constantly control maturation and function of microglia in the CNS.” Nature neuroscience (2015).