Mycophenolate mofetil reduces the branching of microglial processes

Area of Science:

• Neuroscience
• Immunology
• Cell Biology

Background:

• Microglia are central nervous system immune cells vital for brain function, including neurogenesis and circuit formation.
• Microglial process dynamics are crucial for brain surveillance.
• The purine salvage pathway influences microglial morphology and dynamics.

Purpose of the Study:

• To investigate the effect of mycophenolate mofetil (MMF), an inosine monophosphate dehydrogenase (IMPDH) inhibitor, on microglial development.
• To explore the role of guanosine nucleotides in microglial branching and diversity.

Main Methods:

• Administration of MMF to rodents during postnatal development.
• Imaging mass spectrometry to analyze brain nucleotide levels.
• Assessment of microglial proliferation, morphology, and small GTPase activity (RhoA, Rac1).

Main Results:

• MMF administration reduced microglial branching but did not affect process length or proliferation.
• MMF decreased guanosine nucleotide levels in the brain.
• MMF attenuated GTP-bound forms of RhoA and Rac1 small GTPases.

Conclusions:

• Guano sine nucleotide production is essential for proper microglial branching and complexity.
• MMF impacts microglial diversity by affecting guanosine nucleotide synthesis.
• These findings reveal a novel mechanism regulating microglial morphology and function.