Detergent-like Interaction of Congo Red with the Amyloid β Peptide.

Accumulating evidence links prefibrillar oligomeric species of the amyloid β peptide (Aβ) to cellular toxicity in Alzheimer's disease, potentially via disruption of biological membranes. Congo red (CR) affects protein aggregation. It is known to self-associate into micelle-like assemblies but still reduces the toxicity of Aβ aggregates in cell cultures and model organisms. We show here that CR interacts with Aβ(l -40) in a manner similar to that of anionic detergents. Although CR promotes /i sheet formation and peptide aggregation, it may also solubilize toxic protein species, making them less harmful to critical cellular components and thereby reducing amyloid toxicity. [ABSTRACT FROM AUTHOR]