Original Article: https://doi.org/10.1038/s41586-020-2745-3
- Dysbiosis is a term for a microbial imbalance or maladaptation on or inside the body.
- Dysbiosis of the gut microbiome during pregnancy, in response to challenges such as infection, altered diet and stress during pregnancy, has been increasingly correlated with abnormal brain function and behavior of the offspring.
- It is uncertain whether the maternal gastrointestinal microbiome influences nervous system development during critical prenatal periods and in the absence of environmental challenges.
- Researchers investigate how reduction and selective reconstitution of the maternal gut microbiome influences neural development in fetal mice.
- Embryos from antibiotic-treated and germ-free dams exhibited reduced brain expression of genes related to the formation of new nerve fibers, deficiency in thalamus-cerebral cortex axons and impaired outgrowth of thalamic axons in response to cell-extrinsic factors.
- Introduction with a limited consortium of bacteria in microbiome-depleted dams prevented abnormalities in fetal brain gene expression and the formation of nerve fibers in thalamus and cerebral cortex.
- Metabolomic profiling revealed that the maternal microbiome regulates numerous small molecules in the maternal serum and the brains of fetal offspring.
- Serum is the clear liquid that can be separated from clotted blood.
- Metabolic profiling involves the identification and quantification of specific endogenous metabolites.
- Select microbiota-dependent metabolites promoted axon outgrowth from fetal thalamic explants.
- Explants are pieces of tissue which has been transferred from animals or plants to a nutrient medium.
- In addition, maternal supplementation with these metabolites removed deficiencies in fetal thalamus-cerebral cortex axons.
- Manipulation of the maternal microbiome and microbial metabolites during pregnancy yielded adult offspring with altered sense of touch in two aversive somatosensory behavioral tasks.
- The manipulation did not yield apparent differences in many other sensorimotor behaviors.
- The study show that the maternal gut microbiome promotes fetal thalamocortical axon formation, probably through signaling by microbiome-modulated metabolites to neurons in the developing brain.
Vuong, H.E., Pronovost, G.N., Williams, D.W. et al. The maternal microbiome modulates fetal neurodevelopment in mice. Nature (2020). https://doi.org/10.1038/s41586-020-2745-3