Microglia: active sensor and versatile effector cells in the normal and pathologic brain

Area of Science:

• Neuroscience
• Immunology
• Cell Biology

Background:

• Microglia are the primary immune cells in the central nervous system (CNS).
• Traditionally considered 'resting' in a normal brain, recent studies reveal microglia actively scan neural tissue.
• Microglial activation, a known response to pathology, is now understood to be more diverse and dynamic than previously thought.

Purpose of the Study:

• To review key findings on the multifaceted activities of microglia.
• To explore the dynamic and diverse nature of microglial responses in both normal and pathological CNS conditions.
• To highlight the heterogeneity of microglial reactions in different disease contexts.

Main Methods:

• Review of recent in vivo studies on microglial behavior.
• Analysis of transcriptional and non-transcriptional features of microglial activation.
• Examination of functional consequences of microglial engagement in disease.

Main Results:

• Microglia exhibit active tissue scanning in the normal brain.
• Microglial activation involves diverse transcriptional and non-transcriptional changes.
• Microglial responses can be either neuroprotective or neurotoxic, influencing disease progression.
• Significant heterogeneity exists in microglial responses across different pathologies and disease stages.

Conclusions:

• Microglial cells play a complex and dynamic role in CNS health and disease.
• Understanding microglial heterogeneity is crucial for deciphering their dual role in neuroprotection and neurotoxicity.
• Further research into microglial functions can inform therapeutic strategies for neurological disorders.