A novel microglial subset plays a key role in myelinogenesis in developing brain.
Level 5 - mechanism / opinion, no new human data
Preclinical animal and bench research with no human data.
PubMed 28963396 · doi:10.15252/embj.201696056
What was done
Researchers investigated the functional and phenotypic characteristics of neonatal microglia compared to adult and inflammation-activated microglia in mouse models. They characterized CD11c-positive (CD11c+) microglia in primary myelinating regions of developing brains, evaluated gene expression, selectively depleted insulin-like growth factor 1 (IGF-1) from this subset, and evaluated responses to CD11c-targeted toxin ablation in neonatal versus adult mice.
What was found
Neonatal microglia displayed a distinct myelinogenic and neurogenic phenotype compared to adult microglia. The CD11c+ subset predominated in primary myelinating regions and expressed genes supporting neuronal and glial survival, migration, and differentiation. CD11c+ microglia were the primary source of IGF-1, and selective depletion of IGF-1 from these cells resulted in impaired primary myelination. CD11c-targeted toxin ablation elicited a neonatal-specific transcriptional response. Repopulating or inflammation-associated CD11c+ microglia in adult mice did not recapitulate the neonatal phenotype. No numerical data or exact sample sizes were reported in the abstract.
Why it matters
The findings identify a specialized transient subset of neonatal microglia that provides trophic signals, specifically IGF-1, required for primary myelination and neurogenesis in early brain development.
Limits
The study was conducted entirely in animal models and bench experiments, and the abstract reports no sample sizes, effect sizes, or quantitative data. Applicability to human brain development and clinical translation is unproven.
Cited by
- supports Resistance training increases IGF-1, which is critical for the development and maintenance of white matter structure in the brain across the lifespan.