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Updated: Mar 28, 2026
A11-positive β-amyloid Oligomer Preparation and Assessment Using Dot Blotting Analysis
Published on: May 22, 2018
Single molecule experiments emphasize GM1 as a key player of the different cytotoxicity of structurally distinct
Martino Calamai1, Elisa Evangelisti2, Roberta Cascella2
1European Laboratory for Non-linear Spectroscopy (LENS), University of Florence, 50019 Florence, Italy; National Institute of Optics, National Research Council of Italy (CNR), Largo Fermi 6, 50125, Florence, Italy.
Abstract:
It is well established that cytotoxic Aβ oligomers are the key factor that triggers the initial tissue and cell modifications eventually culminating in the development of Alzheimer's disease. Aβ1-42 oligomers display a high degree of polymorphism, and several structurally different oligomers have been described. Amongst them, two types, recently classified as A+ and A-, have been shown to possess similar size but distinct toxic properties, as a consequence of their biophysical and structural differences. Here, we have investigated by means of single molecule tracking the oligomer mobility on the plasma membrane of living neuroblastoma cells and the interaction with the ganglioside GM1, a component of membrane rafts. We have found that A+ and A- oligomers display a similar lateral diffusion on the plasma membrane of living cells. However, only the toxic A+ oligomers appear to interact and alter the mobility of GM1. We have also studied the lateral diffusion of each kind of oligomers in cells depleted or enriched in GM1. We found that the content of GM1 influences the diffusion of both types of oligomer, although the effect of the increased levels of GM1 is higher for the A+ type. Interestingly, the content of GM1 also affects significantly the mobility of GM1 molecules themselves.
Insights
Toxic amyloid-beta (Aβ) oligomers are central to Alzheimer's disease. This study shows toxic A+ oligomers interact with GM1 gangliosides, altering their mobility and influencing Aβ diffusion, unlike non-toxic A- oligomers.
Area of Science:
- Neuroscience
- Biochemistry
- Cell Biology
Background:
- Cytotoxic amyloid-beta (Aβ) oligomers are key drivers of Alzheimer's disease pathology.
- Aβ1-42 oligomers exhibit polymorphism, with distinct subtypes like A+ and A- possessing different toxicities.
- Ganglioside GM1, a component of membrane rafts, is implicated in cellular processes relevant to neurodegeneration.
Purpose of the Study:
- To investigate the mobility and interactions of distinct Aβ oligomer subtypes (A+ and A-) on living neuroblastoma cell membranes.
- To determine the role of ganglioside GM1 in modulating the behavior and toxicity of Aβ oligomers.
- To elucidate the specific interactions between toxic A+ oligomers and GM1 within membrane rafts.
Main Methods:
- Single molecule tracking to analyze oligomer diffusion on the plasma membrane.
- Utilizing neuroblastoma cell models with varying GM1 ganglioside content (depleted or enriched).
- Assessing the impact of GM1 levels on the lateral mobility of both A+ and A- oligomers and GM1 itself.
Main Results:
- Both A+ and A- oligomers exhibited similar lateral diffusion rates on cell membranes.
- Toxic A+ oligomers, but not A- oligomers, interacted with and altered the mobility of GM1 gangliosides.
- GM1 content significantly influenced the diffusion of both oligomer types, with a more pronounced effect on A+ oligomers.
- GM1 molecule mobility was also significantly affected by the cellular GM1 content.
Conclusions:
- The interaction between toxic A+ oligomers and GM1 is specific and impacts GM1 mobility.
- GM1 ganglioside plays a crucial role in modulating the diffusion and potentially the toxicity of Aβ oligomers.
- These findings highlight GM1 as a potential target for understanding and mitigating Alzheimer's disease progression.
