title: N-Terminal pyroglutamate formation of Aβ38 and Aβ40 enforces oligomer formation and potency to disrupt hippocampal long-term potentiation.
abstract: Pyroglutamate (pGlu)-modified amyloid peptides have been identified in sporadic and familial forms of Alzheimer's disease (AD) and the inherited disorders familial British and Danish Dementia (FBD and FDD). In this study, we characterized the aggregation of amyloid-β protein Aβ37, Aβ38, Aβ40, Aβ42 and ADan species in vitro, which were modified by N-terminal pGlu (pGlu-Aβ3-x, pGlu-ADan) or possess the intact N-terminus (Aβ1-x, ADan). The pGlu-modification confers rapid formation of oligomers and short fibrillar aggregates. In accordance with these observations, the pGlu-modified Aβ38, Αβ40 and Αβ42 species inhibit hippocampal long term potentiation of synaptic response, but pGlu-Aβ3-42 showing the highest effect. Among the unmodified Aβ peptides, only Aβ1-42 exhibites such propensity, which was similar to pGlu-Aβ3-38 and pGlu-Aβ3-40. Likewise, the amyloidogenic peptide pGlu-ADan impaired synaptic potentiation more pronounced than N-terminal unmodified ADan. The results were validated using conditioned media from cultivated HEK293 cells, which express APP variants favoring the formation of Aβ1-x, Aβ3-x or N-truncated pGlu-Aβ3-x species. Hence, we show that the ability of different amyloid peptides to impair synaptic function apparently correlates to their potential to form oligomers as a common mechanism. The pGlu-modification is apparently mediating a higher surface hydrophobicity, as shown by 1-anilinonaphtalene-8-sulfonate fluorescence, which enforces potential to interfere with neuronal physiology.
authors.affiliation: Probiodrug AG, Halle/Saale, Germany.
authors.forename: Dagmar
authors.initials: D
authors.lastname: Schlenzig
authors.forename: Raik
authors.initials: R
authors.lastname: Rönicke
authors.forename: Holger
authors.initials: H
authors.lastname: Cynis
authors.forename: Hans-Henning
authors.initials: HH
authors.lastname: Ludwig
authors.forename: Eike
authors.initials: E
authors.lastname: Scheel
authors.forename: Klaus
authors.initials: K
authors.lastname: Reymann
authors.forename: Takaomi
authors.initials: T
authors.lastname: Saido
authors.forename: Gerd
authors.initials: G
authors.lastname: Hause
authors.forename: Stephan
authors.initials: S
authors.lastname: Schilling
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Demuth
mesh_terms: D000544:Alzheimer Disease / Q000378:metabolism*; D016229:Amyloid beta-Peptides / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D057809:HEK293 Cells; D006624:Hippocampus / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D017774:Long-Term Potentiation / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D046529:Microscopy, Electron, Transmission; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D011761:Pyrrolidonecarboxylic Acid / Q000737:chemistry / Q000378:metabolism*
chemical_list: D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; D011761:Pyrrolidonecarboxylic Acid