The maternal microbiome modulates fetal neurodevelopment in mice

Area of Science:

• Neuroscience
• Microbiology
• Developmental Biology

Background:

• Maternal gut microbiome dysbiosis is linked to offspring neurodevelopmental abnormalities.
• The role of the maternal microbiome in prenatal neurodevelopment, absent external challenges, remains unclear.

Purpose of the Study:

• To investigate how maternal gut microbiome depletion and reconstitution affect fetal neurodevelopment in mice.
• To identify microbial metabolites involved in regulating fetal brain development.

Main Methods:

• Depletion of maternal gut microbiome using antibiotics and germ-free models.
• Gnotobiotic colonization with specific bacterial consortia.
• Metabolomic profiling of maternal serum and fetal brains.
• Assessment of gene expression, axonogenesis, and behavioral tasks in offspring.

Main Results:

• Maternal microbiome depletion led to reduced gene expression for axonogenesis and deficient thalamocortical axons in fetuses.
• Reconstitution with a limited bacterial consortium prevented these abnormalities.
• Microbiota-dependent metabolites were identified that promote axon outgrowth and rescued developmental deficits.
• Offspring exhibited altered tactile sensitivity, suggesting specific neurodevelopmental impacts.

Conclusions:

• The maternal gut microbiome is essential for fetal thalamocortical axonogenesis.
• Microbially modulated metabolites act as signaling molecules to the developing fetal brain.
• Targeting the maternal microbiome and its metabolites offers a potential strategy for neurodevelopmental interventions.