Embryonic microglia maintain the brain's cortical fault lines

Area of Science:

• Neuroscience
• Developmental Biology
• Immunology

Background:

• Fetal cortical development involves complex cellular interactions.
• Microglia, the brain's immune cells, play critical roles beyond immune surveillance.
• The specific functions of microglia at fetal cortical boundaries are not well understood.

Purpose of the Study:

• To investigate the role of microglia at fetal cortical boundaries.
• To understand how morphogenetic stress influences microglia states.
• To identify the mechanisms by which microglia prevent cavitary lesion formation.

Main Methods:

• Analysis of microglia states in response to fetal cortical stress.
• Investigation of the molecular regulation of microglia function, including Spp1.
• Assessment of phagocytosis of extracellular matrix proteins like fibronectin 1.

Main Results:

• Fetal cortical boundaries are sensitive to morphogenetic stress.
• This stress induces a microglia state similar to postnatal axon-tract associated microglia (ATM).
• This ATM-like state prevents cavitary lesion formation via Spp1-regulated fibronectin 1 phagocytosis.

Conclusions:

• Microglia exhibit a specialized, protective function at fetal cortical boundaries.
• The Spp1-mediated phagocytosis pathway is crucial for preventing lesions during development.
• These findings reveal a novel role for microglia in maintaining brain structural integrity during development.