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Pyroglutamate-modified amyloid-β (pE-Aβ) is a highly neurotoxic amyloid-β (Aβ) isoform and is enriched in the brains of individuals with Alzheimer disease compared with healthy aged controls. Pyroglutamate formation increases the rate of Aβ oligomerization and alters the interactions of Aβ with Cu(2+) and lipids; however, a link between these properties and the toxicity of pE-Aβ peptides has not been established. We report here that Aβ3pE-42 has an enhanced capacity to cause lipid peroxidation in primary cortical mouse neurons compared with the full-length isoform (Aβ(1-42)). In contrast, Aβ(1-42) caused a significant elevation in cytosolic reactive oxygen species, whereas Aβ3pE-42 did not. We also report that Aβ3pE-42 preferentially associates with neuronal membranes and triggers Ca(2+) influx that can be partially blocked by the N-methyl-d-aspartate receptor antagonist MK-801. Aβ3pE-42 further caused a loss of plasma membrane integrity and remained bound to neurons at significantly higher levels than Aβ(1-42) over extended incubations. Pyroglutamate formation was additionally found to increase the relative efficiency of Aβ-dityrosine oligomer formation mediated by copper-redox cycling.

Original publication

DOI

10.1074/jbc.M115.655183

Type

Journal article

Journal

J Biol Chem

Publication Date

18/03/2016

Volume

291

Pages

6134 - 6145

Keywords

Alzheimer disease, amyloid-beta (Aβ), dityrosine, lipid peroxidation, oligomer, pyroglutamate, reactive oxygen species (ROS), Alzheimer Disease, Amyloid beta-Peptides, Animals, Ascorbic Acid, Calcium Signaling, Cell Membrane Permeability, Cells, Cultured, Copper, Humans, Lipid Peroxidation, Mice, Inbred C57BL, Neurons, Peptide Fragments, Protein Aggregates, Pyrrolidonecarboxylic Acid, Reactive Oxygen Species, Tyrosine