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Updated: Aug 2, 2026
Preparation of Oligomeric β-amyloid1-42 and Induction of Synaptic Plasticity Impairment on Hippocampal Slices
Published on: July 14, 2010
Lipoprotein effects on Abeta accumulation and degradation by microglia in vitro
G M Cole1, W Beech, S A Frautschy
1Sepulveda VAMC, GRECC, and Departments of Medicine and Neurology, University of California-Los Angeles, Sepulveda 91343, USA. gmcole@UCLA.edu
Abstract:
An inflammatory response involving activated microglia in neuritic beta-amyloid plaques is found in Alzheimer's disease (AD) brain. Because HDL lipoproteins have been shown to carry the beta-amyloid peptide (Abeta) in plasma and CSF, we have investigated the influence of plasma high-density lipoprotein (HDL) and lipidated ApoE and ApoJ particles on the interaction of cultured rat microglia with Abeta1-42. Microglia degraded Abeta via a pathway sensitive to cytochalasin D and the scavenger receptor inhibitor, fucoidan. HDL increased the degradation of Abeta and the ratio of multimeric/monomeric Abeta in a dose-dependent manner. In contrast, lipidated ApoJ and ApoE decreased the degradation of Abeta, and the effects were ApoE isoform-dependent. Immuno-electron microscopy revealed internalized Abeta in endosomes and lysosomes as well as cell-associated Abeta in deep invaginations, which may be related to caveolae and surface-connected compartments. These data suggest that lipoprotein-dependent Abeta trafficking to microglia could be relevant to plaque pathogenesis in AD.
Insights
High-density lipoprotein (HDL) enhances beta-amyloid (Abeta) degradation by microglia, a key process in Alzheimer's disease (AD) pathogenesis. Other lipoproteins like ApoE and ApoJ inhibit this Abeta clearance.
Area of Science:
- Neuroscience
- Immunology
- Biochemistry
Background:
- Alzheimer's disease (AD) is characterized by neuroinflammation involving activated microglia and beta-amyloid (Abeta) plaques.
- High-density lipoprotein (HDL) and apolipoproteins (ApoE, ApoJ) transport Abeta in biological fluids.
Purpose of the Study:
- To investigate the influence of plasma HDL and lipidated ApoE/ApoJ on microglial interaction with Abeta1-42.
- To understand the role of lipoproteins in Abeta trafficking and degradation by microglia.
Main Methods:
- Cultured rat microglia were treated with Abeta1-42 in the presence of HDL, ApoE, or ApoJ.
- Abeta degradation was quantified, and cellular uptake was visualized using immuno-electron microscopy.
- Involvement of specific pathways was assessed using cytochalasin D and fucoidan.
Main Results:
- HDL significantly increased Abeta degradation and the multimeric/monomeric Abeta ratio in a dose-dependent manner.
- Lipidated ApoJ and ApoE decreased Abeta degradation, with ApoE effects being isoform-dependent.
- Internalized Abeta was observed in endosomes/lysosomes, and cell-associated Abeta was found in deep invaginations.
Conclusions:
- HDL promotes microglial clearance of Abeta, potentially mitigating plaque formation in AD.
- ApoE and ApoJ inhibit microglial Abeta degradation, suggesting a complex role in AD pathogenesis.
- Lipoprotein-mediated Abeta trafficking to microglia is a critical factor in Alzheimer's disease progression.
