title: The oxidative stress metabolite 4-hydroxynonenal promotes Alzheimer protofibril formation.
abstract: 4-Hydroxynonenal (4-HNE), formed as a consequence of oxidative stress, exists at increased concentrations in Alzheimer's disease (AD) patients and is found in amyloid beta peptide (Abeta) plaques associated with AD. Although it remains an open question as to whether oxidative stress is a causative factor or a consequence of AD, we show here that 4-HNE, putatively resulting from the peroxidation of lipids, covalently modifies Abeta, triggering its aggregation. These Abeta modifications result from 1,4 conjugate addition and/or Schiff base formation, they occur at multiple locations on a single Abeta peptide, and they result in covalent cross-linking of Abeta peptides. The consequence of these reactions is that 4-HNE accelerates the formation of Abeta protofibrils while inhibiting the production of straight, mature fibrils. Recent studies implicating Abeta oligomers and protofibrils in the neurotoxic process that ultimately leads to AD suggest that the Abeta aggregates induced by 4-HNE may be important in the pathogenesis of AD. These results provide further incentive to understand the role of oxidative stress and small-molecule Abeta modifications in sporadic AD.
authors.affiliation: The Scripps Research Institute, and The Skaggs Institute for Chemical Biology, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Siegel
authors.forename: Jan
authors.initials: J
authors.lastname: Bieschke
authors.forename: Evan T
authors.initials: ET
authors.lastname: Powers
authors.forename: Jeffery W
authors.initials: JW
authors.lastname: Kelly
mesh_terms: D000447:Aldehydes / Q000494:pharmacology*; D000544:Alzheimer Disease / Q000378:metabolism; D016229:Amyloid beta-Peptides / Q000187:drug effects* / Q000648:ultrastructure; D002850:Chromatography, Gel; D006801:Humans; D018384:Oxidative Stress / Q000502:physiology*; D010446:Peptide Fragments / Q000187:drug effects* / Q000648:ultrastructure; D011487:Protein Conformation; D020836:Protein Structure, Quaternary; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000447:Aldehydes; D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; C078592:amyloid beta-protein (1-40); C027576:4-hydroxy-2-nonenal