Amyloidβ Peptides in interaction with raft-mime model membranes: A neutron reflectivity insight

Valeria Rondelli, Paola Brocca, Simona Motta, Massimo Messa, Laura Colombo, Mario Salmona, Giovanna Fragneto, Laura Cantu, Elena Del Favero

Research output: Contribution to journalArticlepeer-review

Abstract

The role of first-stage β-amyloid aggregation in the development of the Alzheimer disease, is widely accepted but still unclear. Intimate interaction with the cell membrane is invoked. We designed Neutron Reflectometry experiments to reveal the existence and extent of the interaction between β-amyloid (Aβ) peptides and a lone customized biomimetic membrane, and their dependence on the aggregation state of the peptide. The membrane, asymmetrically containing phospholipids, GM1 and cholesterol in biosimilar proportion, is a model for a raft, a putative site for amyloid-cell membrane interaction. We found that the structured-oligomer of Aβ(1-42), its most acknowledged membrane-active state, is embedded as such into the external leaflet of the membrane. Conversely, the Aβ(1-42) unstructured early-oligomers deeply penetrate the membrane, likely mimicking the interaction at neuronal cell surfaces, when the Aβ(1-42) is cleaved from APP protein and the membrane constitutes a template for its further structural evolution. Moreover, the smaller Aβ(1-6) fragment, the N-terminal portion of Aβ, was also used. Aβ N-terminal is usually considered as involved in oligomer stabilization but not in the peptide-membrane interaction. Instead, it was seen to remove lipids from the bilayer, thus suggesting its role, once in the whole peptide, in membrane leakage, favouring peptide recruitment.

Original languageEnglish
Article number20997
JournalScientific Reports
Volume6
DOIs
Publication statusPublished - Feb 16 2016

ASJC Scopus subject areas

  • General

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