title: Analysis of Toxic Amyloid Fibril Interactions at Natively Derived Membranes by Ellipsometry.
abstract: There is an ongoing debate regarding the culprits of cytotoxicity associated with amyloid disorders. Although small pre-fibrillar amyloid oligomers have been implicated as the primary toxic species, the fibrillar amyloid material itself can also induce cytotoxicity. To investigate membrane disruption and cytotoxic effects associated with intact and fragmented fibrils, the novel in situ spectroscopic technique of Total Internal Reflection Ellipsometry (TIRE) was used. Fibril lipid interactions were monitored using natively derived whole cell membranes as a model of the in vivo environment. We show that fragmented fibrils have an increased ability to disrupt these natively derived membranes by causing a loss of material from the deposited surface when compared with unfragmented fibrils. This effect was corroborated by observations of membrane disruption in live cells, and by dye release assay using synthetic liposomes. Through these studies we demonstrate the use of TIRE for the analysis of protein-lipid interactions on natively derived lipid surfaces, and provide an explanation on how amyloid fibrils can cause a toxic gain of function, while entangled amyloid plaques exert minimal biological activity.
authors.affiliation: Biomedical Research Centre, Sheffield Hallam University, Sheffield, United Kingdom.
authors.forename: Rachel A S
authors.initials: RA
authors.lastname: Smith
authors.affiliation: Materials and Engineering Research Institute, Sheffield Hallam University, Sheffield, United Kingdom.
authors.forename: Aleksey
authors.initials: A
authors.lastname: Nabok
authors.affiliation: School of Biosciences, University of Kent, Canterbury, Kent, United Kingdom.
authors.forename: Ben J F
authors.initials: BJ
authors.lastname: Blakeman
authors.affiliation: School of Biosciences, University of Kent, Canterbury, Kent, United Kingdom.
authors.forename: Wei-Feng
authors.initials: WF
authors.lastname: Xue
authors.affiliation: Biomedical Research Centre, Sheffield Hallam University, Sheffield, United Kingdom.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Abell
authors.affiliation: Biomedical Research Centre, Sheffield Hallam University, Sheffield, United Kingdom.
authors.forename: David P
authors.initials: DP
authors.lastname: Smith
mesh_terms: D000682:Amyloid / Q000378:metabolism* / Q000633:toxicity*; D016229:Amyloid beta-Peptides / Q000378:metabolism / Q000633:toxicity; D000818:Animals; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000187:drug effects* / Q000378:metabolism*; D006801:Humans; D008081:Liposomes / Q000378:metabolism; D009113:Muramidase / Q000378:metabolism / Q000633:toxicity; D055620:Optical Phenomena; D010446:Peptide Fragments / Q000378:metabolism / Q000633:toxicity; D011485:Protein Binding; D051844:alpha-Synuclein / Q000378:metabolism / Q000633:toxicity
chemical_list: D000682:Amyloid; D016229:Amyloid beta-Peptides; D008081:Liposomes; D010446:Peptide Fragments; D051844:alpha-Synuclein; C078592:amyloid beta-protein (1-40); D009113:Muramidase