title: Surface chemistry of lipid raft and amyloid Aβ (1-40) Langmuir monolayer.
abstract: Lipid rafts being rich in cholesterol and sphingolipids are considered to provide ordered lipid environment in the neuronal membranes, where it is hypothesized that the cleavage of amyloid precursor protein (APP) to Aβ (1-40) and Aβ (1-42) takes place. It is highly likely that the interaction of lipid raft components like cholesterol, sphingomylein or GM1 leads to nucleation of Aβ and results in aggregation or accumulation of amyloid plaques. One has investigated surface pressure-area isotherms of the lipid raft and Aβ (1-40) Langmuir monolayer. The compression-decompression cycles and the stability of the lipid raft Langmuir monolayer are crucial parameters for the investigation of interaction of Aβ (1-40) with the lipid raft Langmuir monolayer. It was revealed that GM1 provides instability to the lipid raft Langmuir monolayer. Adsorption of Aβ (1-40) onto the lipid raft Langmuir monolayer containing neutral (POPC) or negatively charged phospholipid (DPPG) was examined. The adsorption isotherms revealed that the concentration of cholesterol was important for adsorption of Aβ (1-40) onto the lipid raft Langmuir monolayer containing POPC whereas for the lipid raft Langmuir monolayer containing DPPG:cholesterol or GM1 did not play any role. In situ UV-vis absorption spectroscopy supported the interpretation of results for the adsorption isotherms.
authors.affiliation: Department of Chemistry, University of Miami, Coral Gables, FL 33146, USA.
authors.forename: Garima
authors.initials: G
authors.lastname: Thakur
authors.forename: Christine
authors.initials: C
authors.lastname: Pao
authors.forename: Miodrag
authors.initials: M
authors.lastname: Micic
authors.forename: Sheba
authors.initials: S
authors.lastname: Johnson
authors.forename: Roger M
authors.initials: RM
authors.lastname: Leblanc
mesh_terms: D000327:Adsorption; D000544:Alzheimer Disease / Q000378:metabolism / Q000473:pathology; D016229:Amyloid beta-Peptides / Q000737:chemistry* / Q000378:metabolism; D000818:Animals; D002417:Cattle; D002627:Chemistry, Physical / Q000379:methods*; D002784:Cholesterol / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008081:Liposomes / Q000737:chemistry* / Q000378:metabolism; D021962:Membrane Microdomains / Q000737:chemistry* / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry* / Q000378:metabolism; D010713:Phosphatidylcholines / Q000737:chemistry; D010715:Phosphatidylglycerols / Q000737:chemistry; D058225:Plaque, Amyloid / Q000737:chemistry* / Q000378:metabolism; D017433:Protein Structure, Secondary; D013057:Spectrum Analysis; D013107:Sphingolipids / Q000737:chemistry; D055672:Static Electricity; D013499:Surface Properties
chemical_list: D016229:Amyloid beta-Peptides; D008081:Liposomes; D010446:Peptide Fragments; D010713:Phosphatidylcholines; D010715:Phosphatidylglycerols; D013107:Sphingolipids; C078592:amyloid beta-protein (1-40); D002784:Cholesterol; C028694:1-palmitoyl-2-oleoylphosphatidylcholine; C030345:1,2-dipalmitoylphosphatidylglycerol