title: Aggregation of Aß(25-35) on DOPC and DOPC/DHA bilayers: an atomic force microscopy study.
abstract: β amyloid peptide plays an important role in both the manifestation and progression of Alzheimer disease. It has a tendency to aggregate, forming low-molecular weight soluble oligomers, higher-molecular weight protofibrillar oligomers and insoluble fibrils. The relative importance of these single oligomeric-polymeric species, in relation to the morbidity of the disease, is currently being debated. Here we present an Atomic Force Microscopy (AFM) study of Aβ(25-35) aggregation on hydrophobic dioleoylphosphatidylcholine (DOPC) and DOPC/docosahexaenoic 22∶6 acid (DHA) lipid bilayers. Aβ(25-35) is the smallest fragment retaining the biological activity of the full-length peptide, whereas DOPC and DOPC/DHA lipid bilayers were selected as models of cell-membrane environments characterized by different fluidity. Our results provide evidence that in hydrophobic DOPC and DOPC/DHA lipid bilayers, Aβ(25-35) forms layered aggregates composed of mainly annular structures. The mutual interaction between annular structures and lipid surfaces end-results into a membrane solubilization. The presence of DHA as a membrane-fluidizing agent is essential to protect the membrane from damage caused by interactions with peptide aggregates; to reduces the bilayer defects where the delipidation process starts.
authors.affiliation: Physics Department and Research Centre for Nanomaterials and Nanotechnology, University of Salerno, Via Giovanni Paolo II, 132, 84084, Fisciano (SA), Italy.
authors.forename: Matilde
authors.initials: M
authors.lastname: Sublimi Saponetti
authors.affiliation: Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132, 84084, Fisciano (SA), Italy.
authors.forename: Manuela
authors.initials: M
authors.lastname: Grimaldi
authors.affiliation: Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132, 84084, Fisciano (SA), Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Scrima
authors.affiliation: Institute for Superconductivity and Innovative Materials of the Italian National Research Council, Via Giovanni Paolo II, 132, 84084, Fisciano (SA), Italy; Institute Study Nanostructurated Materials of the Italian National Research Council, Via P. Gobetti 101, 40129, Bologna, Italy.
authors.forename: Cristiano
authors.initials: C
authors.lastname: Albonetti
authors.affiliation: Department of Medicine and Surgery, University of Salerno, Via Salvatore Allende, 84081, Baronissi (SA), Italy.
authors.forename: Stefania Lucia
authors.initials: SL
authors.lastname: Nori
authors.affiliation: Physics Department and Research Centre for Nanomaterials and Nanotechnology, University of Salerno, Via Giovanni Paolo II, 132, 84084, Fisciano (SA), Italy; Institute for Superconductivity and Innovative Materials of the Italian National Research Council, Via Giovanni Paolo II, 132, 84084, Fisciano (SA), Italy.
authors.forename: Annamaria
authors.initials: A
authors.lastname: Cucolo
authors.affiliation: Physics Department and Research Centre for Nanomaterials and Nanotechnology, University of Salerno, Via Giovanni Paolo II, 132, 84084, Fisciano (SA), Italy; Institute for Superconductivity and Innovative Materials of the Italian National Research Council, Via Giovanni Paolo II, 132, 84084, Fisciano (SA), Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Bobba
authors.affiliation: Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132, 84084, Fisciano (SA), Italy.
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: D'Ursi
mesh_terms: D000544:Alzheimer Disease / Q000473:pathology; D016229:Amyloid beta-Peptides / Q000737:chemistry*; D002462:Cell Membrane / Q000378:metabolism; D004281:Docosahexaenoic Acids / Q000737:chemistry*; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008051:Lipid Bilayers / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D010713:Phosphatidylcholines / Q000737:chemistry*; D058225:Plaque, Amyloid / Q000737:chemistry
chemical_list: D016229:Amyloid beta-Peptides; D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D004281:Docosahexaenoic Acids; C017251:1,2-oleoylphosphatidylcholine