The Functions and Phenotypes of Microglia in Alzheimer's Disease

Area of Science:

• Neuroscience
• Immunology
• Genetics

Background:

• Alzheimer's disease (AD) is a leading cause of neurodegeneration globally, with limited therapeutic success.
• Microglia, the resident immune cells of the central nervous system, are increasingly recognized for their importance in AD.
• Recent advancements reveal diverse microglial cell states within AD.

Purpose of the Study:

• To systematically review microglial responses to key AD pathologies (amyloid-β and tau tangles).
• To examine microglial risk factor gene expression in AD.
• To discuss protective microglial phenotypes and their link to AD-associated inflammation and chronic pain.

Main Methods:

• Systematic review of scientific literature on microglia in Alzheimer's disease.
• Analysis of single-cell RNA sequencing data to identify heterogeneous microglial states.
• Integration of findings on amyloid-β, tau pathology, risk genes, and inflammation.

Main Results:

• Microglia exhibit heterogeneous responses to amyloid-β plaques and tau tangles.
• Specific risk factor genes are expressed by microglia in AD.
• Protective microglial states and their connection to inflammation in AD and chronic pain are identified.

Conclusions:

• Microglial heterogeneity is central to Alzheimer's disease pathogenesis.
• Targeting specific microglial states offers potential therapeutic avenues for AD.
• Further understanding of microglia-immune interactions is crucial for novel AD treatment strategies.