Copper Modulation of Amyloid Beta 42 Interactions with Model Membranes

Abstract

Growing evidence supports that interactions of the amyloid-β peptide Aβ(1–42) with neuronal cell membranes and copper are involved in Alzheimer’s disease pathogenesis. We report using solid-state NMR that the peptide significantly perturbed the phosphate and upper acyl chain region of bilayers comprising brain total lipid extract to cause domain segregation. Deep headgroup perturbations were also realized for palmitoyloleoylphospatidylcholine–cholesterol model systems; however, incorporating 10 % palmitoyloleoylphosphatidylserine or the ganglioside GM1 resulted in a more peripheral interaction. Cu2+ at a 1 : 7 molar ratio to peptide caused deeper penetration into model systems, but partially attenuated interactions with brain total lipid extract. Thioflavin T assay showed that bilayers affected amyloid formation in a mode dependant on lipid content, and was further modulated by addition of Cu2+. Our data support that ternary interactions between Cu2+, lipids and Aβ(1–42) may have significance in Alzheimer’s disease, and challenge the validity of model bilayers as substitutes for natural systems.