Inhibition of Aβ Aggregation by Cholesterol-End-Modified PEG Vesicles and Micelles

Area of Science:

• Nanotechnology for drug delivery
• Neurodegenerative disease therapeutics
• Biomaterials science

Background:

• Alzheimer's disease (AD) is characterized by amyloid-beta (Aβ) aggregation.
• Developing effective drug delivery systems (DDS) that can also inhibit Aβ aggregation is crucial for AD treatment.
• Cholesterol-PEG (Chol-PEG) assemblies offer potential as dual-function platforms.

Purpose of the Study:

• To design and evaluate Chol-PEG2000 micelles and Chol-PEG500 vesicles as DDS carriers.
• To assess the inhibitory effects of these Chol-PEG assemblies on Aβ aggregation.
• To explore their potential for a comprehensive AD therapeutic strategy.

Main Methods:

• Characterization of Chol-PEG assemblies using dynamic light scattering (DLS), electrophoretic light scattering (ELS), and transmission electron microscopy (TEM).
• Assessment of Aβ aggregation inhibition via thioflavin T (ThT) assay, circular dichroism (CD) spectroscopy, and native polyacrylamide gel electrophoresis (native-PAGE).
• Evaluation of physical properties, including size, surface charge, and affinity for Aβ.

Main Results:

• Chol-PEG2000 micelles (20-30 nm) and Chol-PEG500 vesicles (70-80 nm) exhibited neutral surface charges and high affinity for Aβ.
• Chol-PEG500 demonstrated superior inhibition of Aβ fibril elongation (40 hours) compared to Chol-PEG2000 (20 hours) at a 10-fold molar ratio.
• Both assemblies significantly inhibited Aβ aggregation at a 50-fold molar ratio, maintaining Aβ's random coil structure and forming transient complexes.

Conclusions:

• Chol-PEG500 vesicles are more effective inhibitors of Aβ aggregation than Chol-PEG2000 micelles.
• Chol-PEG assemblies serve as effective DDS carriers and possess inherent Aβ aggregation inhibitory properties.
• This dual-function platform holds promise for delivering therapeutics targeting multiple AD pathologies, potentially leading to a cure.