The behavior and functions of embryonic microglia

Area of Science:

• Neuroscience
• Immunology
• Developmental Biology

Background:

• Microglia are the primary immune cells within the central nervous system.
• Microglial progenitors originate in the yolk sac and migrate to colonize the developing brain.
• These cells interact with neural lineage cells through filopodia extension and migration.

Purpose of the Study:

• To review recent advancements in understanding microglial colonization and functions during embryonic brain development.
• To focus on the dynamic distribution of microglia and their roles in specific brain regions.
• To discuss the molecular mechanisms governing microglial behavior in the developing brain.

Main Methods:

• This is a review article, synthesizing existing research.
• Focuses on analyzing stage-dependent microglial distribution patterns.
• Examines reported functions of microglia in different embryonic brain zones.

Main Results:

• Microglia exhibit stage-dependent distribution changes in the embryonic brain.
• They are homogenously distributed early on, then absent from the cortical plate (CP) from E15-E16, colonizing the ventricular zone (VZ), subventricular zone (SVZ), and intermediate zone (IZ).
• Microglia in the VZ/SVZ/IZ regulate neurogenesis, cell survival, and circuit formation, indirectly aiding post-migratory neuron maturation.

Conclusions:

• Time-dependent microglial distributional shifts are essential for specific regional functions during brain development.
• Microglia play multifaceted roles, influencing neural lineage cells and neuronal maturation.
• Understanding the molecular basis of microglial behavior is key to comprehending embryonic brain development.