Distinct amyloid-β and tau-associated microglia profiles in Alzheimer's disease

Emma Gerrits1, Nieske Brouwer1, Susanne M Kooistra1

  • 1Department of Biomedical Sciences of Cells and Systems, Section Molecular Neurobiology, University of Groningen and University Medical Center Groningen (UMCG), Antonius Deusinglaan 1, 9713AV, Groningen, the Netherlands.

Acta Neuropathologica
|February 20, 2021
PubMed

Insights

Researchers identified two distinct human microglia phenotypes associated with Alzheimer's disease (AD) pathology. Microglia states correlated with amyloid-β and tau loads, offering new therapeutic targets for AD.

Area of Science:

  • Neuroscience
  • Immunology
  • Genomics

Background:

  • Alzheimer's disease (AD) is the leading cause of dementia, characterized by amyloid-β plaques and tau tangles.
  • Microglia, the brain's immune cells, play a crucial role in CNS homeostasis and are implicated in AD pathogenesis.
  • Previous studies in mouse models suggested a phagocytic microglia phenotype in AD, but human microglia responses remained unclear.

Purpose of the Study:

  • To investigate the transcriptional profiles of human microglia in response to Alzheimer's disease (AD) pathology.
  • To identify distinct human microglia phenotypes associated with amyloid-β and tau pathology.
  • To explore potential therapeutic targets for AD by characterizing disease-associated microglia.

Main Methods:

  • Single-nucleus RNA sequencing (snRNAseq) was performed on 482,472 nuclei from human brain samples.
  • Samples included non-demented controls, AD brains with amyloid-β plaques, and AD brains with both amyloid-β and tau pathology.
  • Microglia transcriptional profiles were analyzed to identify distinct cell populations and their association with AD pathologies.

Main Results:

  • Two distinct AD pathology-associated microglia expression profiles were identified within the microglia population.
  • AD1-microglia abundance correlated with amyloid-β load and localized to plaques.
  • AD2-microglia abundance correlated with phospho-tau load and were more prevalent in samples with tau pathology.

Conclusions:

  • This study fully characterizes human disease-associated microglia phenotypes.
  • Findings provide novel insights into the pathophysiological role of microglia in Alzheimer's disease.
  • Identified microglia phenotypes offer potential targets for microglia-state-specific therapeutic strategies in AD.