Impaired αVβ8 and TGFβ signaling lead to microglial dysmaturation and neuromotor dysfunction

Area of Science:

• Neuroscience
• Developmental Biology
• Immunology

Background:

• Microglia are crucial for brain development and neurodegenerative diseases.
• Their role in neurodevelopmental disorders remains unclear.
• Integrin alpha-V-beta-8 (αVβ8) signaling is vital for brain development.

Purpose of the Study:

• To investigate the role of αVβ8 signaling in microglial development.
• To understand the impact of dysregulated microgliogenesis on neurodevelopment.
• To identify potential therapeutic targets for neurodevelopmental disorders.

Main Methods:

• Utilized conditional knockout mice (Itgb8ΔCNS) lacking αVβ8 in the central nervous system.
• Analyzed microglial development and maturation.
• Assessed neurodevelopmental phenotypes, including oligodendrocyte and interneuron populations, and neuromotor function.
• Investigated the effects of early versus late microglial depletion.

Main Results:

• Conditional deletion of αVβ8 blocked microglial maturation from precursors to mature cells.
• These dysmature microglia, resulting from reduced TGFβ signaling during a perinatal window, caused a unique neurodevelopmental syndrome.
• The syndrome included oligodendrocyte maturational arrest, interneuron loss, and spastic neuromotor dysfunction.
• Early, but not late, microglia depletion completely reversed the observed phenotype.

Conclusions:

• αVβ8 and TGFβ signaling are critical for coordinating microgliogenesis with brain development.
• Abnormally programmed microglia or their products can cause neurodevelopmental disorders.
• Targeting microglial development presents a potential therapeutic strategy for specific neurodevelopmental conditions.