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Updated: May 29, 2025
Quantitative 3D In Silico Modeling q3DISM of Cerebral Amyloid-beta Phagocytosis in Rodent Models of Alzheimer's Disease
Published on: December 26, 2016
Reducing microglial lipid load enhances β amyloid phagocytosis in an Alzheimer's disease mouse model
Xiaoting Wu1, James Alastair Miller2, Bernett Teck Kwong Lee2
1School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
Abstract:
Macrophages accumulate lipid droplets (LDs) under stress and inflammatory conditions. Despite the presence of LD-loaded macrophages in many tissues, including the brain, their contribution to neurodegenerative disorders remains elusive. This study investigated the role of lipid metabolism in Alzheimer's disease (AD) by assessing the contribution of LD-loaded brain macrophages, including microglia and border-associated macrophages (BAMs), in an AD mouse model. Particularly, BAMs and activated CD11c+ microglia localized near β amyloid (Aβ) plaques exhibited a pronounced lipid-associated gene signature and a high LD load. Having observed that elevated intracellular LD content correlated inversely with microglial phagocytic activities, we subsequently inhibited LD formation specifically in CX3CR1+ brain macrophages using an inducible APP-KI/Fit2Δφ transgenic mouse model. We demonstrated that reducing LD content in microglia and CX3CR1+ BAMs remarkably improved their phagocytic ability. Furthermore, lowering microglial LDs consistently enhanced their efferocytosis capacities and notably reduced Aβ deposition in the brain parenchyma. Therefore, mitigating LD accumulation in brain macrophages provides perspectives for AD treatment.
Insights
Reducing lipid droplets in brain macrophages, like microglia, enhances their ability to clear amyloid-beta plaques. This finding offers new therapeutic strategies for Alzheimer's disease (AD) by targeting lipid metabolism.
Area of Science:
- Neuroscience
- Immunology
- Metabolic disease
Background:
- Macrophages, including microglia and border-associated macrophages (BAMs) in the brain, accumulate lipid droplets (LDs) during stress and inflammation.
- The role of these LD-loaded macrophages in neurodegenerative disorders like Alzheimer's disease (AD) is not well understood.
Purpose of the Study:
- To investigate the contribution of LD-loaded brain macrophages to Alzheimer's disease pathogenesis.
- To determine if modulating LD accumulation in brain macrophages impacts AD pathology.
Main Methods:
- Utilized an AD mouse model (APP-KI/Fit2Δφ) to assess LD load in microglia and BAMs near amyloid-beta (Aβ) plaques.
- Inhibited LD formation specifically in CX3CR1+ brain macrophages using a transgenic approach.
- Quantified changes in microglial phagocytic and efferocytosis activities and Aβ deposition.
Main Results:
- Activated microglia and BAMs near Aβ plaques showed high LD content and a lipid-associated gene signature.
- Elevated LD content inversely correlated with microglial phagocytic activity.
- Inhibition of LD formation in brain macrophages significantly enhanced their phagocytic and efferocytosis capabilities.
- Reduced LD accumulation led to a notable decrease in brain Aβ deposition.
Conclusions:
- Lipid droplet accumulation impairs the phagocytic function of brain macrophages in the context of Alzheimer's disease.
- Targeting and reducing LDs in microglia and BAMs can enhance their clearance of Aβ pathology.
- Mitigating lipid droplet accumulation in brain macrophages presents a promising therapeutic avenue for Alzheimer's disease treatment.
