Plaque-associated human microglia accumulate lipid droplets in a chimeric model of Alzheimer's disease.
Mol Neurodegener
; 16(1): 50, 2021 07 23.
Article
in En
| MEDLINE
| ID: mdl-34301296
ABSTRACT
BACKGROUND:
Disease-associated microglia (DAMs), that surround beta-amyloid plaques, represent a transcriptionally-distinct microglial profile in Alzheimer's disease (AD). Activation of DAMs is dependent on triggering receptor expressed on myeloid cells 2 (TREM2) in mouse models and the AD TREM2-R47H risk variant reduces microglial activation and plaque association in human carriers. Interestingly, TREM2 has also been identified as a microglial lipid-sensor, and recent data indicates lipid droplet accumulation in aged microglia, that is in turn associated with a dysfunctional proinflammatory phenotype. However, whether lipid droplets (LDs) are present in human microglia in AD and how the R47H mutation affects this remains unknown.METHODS:
To determine the impact of the TREM2 R47H mutation on human microglial function in vivo, we transplanted wild-type and isogenic TREM2-R47H iPSC-derived microglial progenitors into our recently developed chimeric Alzheimer mouse model. At 7 months of age scRNA-seq and histological analyses were performed.RESULTS:
Here we report that the transcriptome of human wild-type TREM2 and isogenic TREM2-R47H DAM xenografted microglia (xMGs), isolated from chimeric AD mice, closely resembles that of human atherosclerotic foam cells. In addition, much like foam cells, plaque-bound xMGs are highly enriched in lipid droplets. Somewhat surprisingly and in contrast to a recent in vitro study, TREM2-R47H mutant xMGs exhibit an overall reduction in the accumulation of lipid droplets in vivo. Notably, TREM2-R47H xMGs also show overall reduced reactivity to plaques, including diminished plaque-proximity, reduced CD9 expression, and lower secretion of plaque-associated APOE.CONCLUSIONS:
Altogether, these results indicate lipid droplet accumulation occurs in human DAM xMGs in AD, but is reduced in TREM2-R47H DAM xMGs, as it occurs secondary to TREM2-mediated changes in plaque proximity and reactivity.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Brain
/
Membrane Glycoproteins
/
Receptors, Immunologic
/
Microglia
/
Alzheimer Disease
/
Lipid Droplets
Type of study:
Risk_factors_studies
Limits:
Animals
/
Humans
Language:
En
Journal:
Mol Neurodegener
Year:
2021
Document type:
Article
Affiliation country:
United States