Neurogenesis and prolongevity signaling in young germ-free mice transplanted with the gut microbiota of old mice
Microbiota transplants (MT) from young or old mice were performed into germ-free young recipient mice (left panel). Representative images of doublecortin stained neurons in the dentate gyrus of young recipient mice receiving microbiota transplant from young or old donors (right panels). Doublecortin staining is shown in red and DAPI counterstain is blue. The white arrows indicate doublecortin positive neurons and the red boxes indicate area that had been magnified. Scale bars, 100 μm. Kundu et al Science Translational Medicine 2019.
Our gut microbiota evolves as we age, yet its effects on host physiology are not clearly understood. This study attempts to understand the effects of these aging associated microbiota changes on host physiology by transplanting microbiota from young and old donor mice into young germ-free recipient mice. Surprisingly, young germ-free mice receiving microbiota transplants from old donors had increased hippocampal neurogenesis, intestinal growth and activation of the pro-longevity “FGF21-AMPK-SIRT1” pathways in the liver. Subsequent metagenomics analysis revealed the potential role of butyrate-producing microbes in mediating these effects. Mice treated with exogenous sodium butyrate recapitulated the phenotypes observed in germ-free mice receiving old donor microbiota. These findings collectively suggest that the gut microbiota of an old host may have beneficial effects in a responsive younger host.
