Effect of Human Infant Gut Microbiota on Mouse Behavior, Dendritic Complexity, and Myelination

Area of Science:

• Neuroscience
• Microbiology
• Developmental Biology

Background:

• The mammalian gut microbiome plays a crucial role in development, with associations noted between infant gut bacteria and cognitive, social, and stress-related brain functions.
• However, the causal relationship between the gut microbiome and brain development remains to be fully elucidated.

Approach:

• This study utilized mouse models colonized with two distinct microbial stool communities derived from human infants.
• Researchers assessed the impact of these humanized gut microbiomes on host behavior, brain myelination, dendritic morphology, and spine density.

Key Points:

• Humanized mice exhibited distinct phenotypes compared to germ-free controls, indicating microbiome influence.
• Social behavior in male humanized mice was reduced compared to controls.
• Myelination in the hippocampus was thinner in humanized mice than in germ-free mice.
• Differential effects on dendritic morphology and spine density were observed between the two humanized groups in the prefrontal cortex and nucleus accumbens.

Conclusions:

• The findings support a causal role for the gut microbiome in mammalian brain development.
• Specific infant gut microbial communities can modulate neurodevelopmental trajectories, affecting behavior and neural structure.
• Further research is warranted to understand the mechanisms by which gut microbes influence brain development.