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Cholesterol and Abeta aggregation.
1Department of Dementia Research, National Institute for Longevity Sciences, Morioka, Obu, Japan. katuhiko@nils.go.jp
Pharmacopsychiatry
|October 24, 2003
Summary
Alzheimer's disease (AD) research reveals cholesterol accelerates amyloid beta-protein (Abeta) binding to GM1 ganglioside (GM1), forming seeds. ApoE4 mice show higher membrane cholesterol, suggesting a link to AD risk.
Area of Science:
- Neuroscience
- Biochemistry
- Pathology
Background:
- Alzheimer's disease (AD) is characterized by amyloid beta-protein (Abeta) deposition.
- A novel Abeta species binding to GM1 ganglioside (GM1) in early AD brains was previously identified.
- Abeta binding to GM1 is hypothesized to induce conformational changes, acting as a seed for aggregation.
Purpose of the Study:
- To investigate the role of cholesterol in Abeta binding to GM1.
- To determine if cholesterol concentration in neuronal membranes is altered by AD risk factors.
- To examine cholesterol distribution in synaptic plasma membranes (SPMs) of human apolipoprotein E (apoE)-knock-in mice.
Main Methods:
- Investigated the effect of increased cholesterol concentration on Abeta-GM1 binding.
- Determined cholesterol distribution in synaptic plasma membranes (SPMs) of human apoE3 and apoE4 knock-in mice.
Main Results:
- Increased cholesterol concentration markedly accelerates Abeta binding to GM1.
- Cholesterol concentration in the exofacial leaflet of SPMs was approximately twice as high in human apoE4-knock-in mice compared to apoE3-knock-in mice.
Conclusions:
- Elevated cholesterol in neuronal membranes accelerates Abeta aggregation.
- This acceleration occurs through the formation of an endogenous Abeta-GM1-cholesterol seed.
- The findings suggest a mechanism linking cholesterol dysregulation and apoE genotype to AD pathogenesis.