title: Amyloid-beta protofibril levels correlate with spatial learning in Arctic Alzheimer's disease transgenic mice.
abstract: Oligomeric assemblies of amyloid-beta (Abeta) are suggested to be central in the pathogenesis of Alzheimer's disease because levels of soluble Abeta correlate much better with the extent of cognitive dysfunctions than do senile plaque counts. Moreover, such Abeta species have been shown to be neurotoxic, to interfere with learned behavior and to inhibit the maintenance of hippocampal long-term potentiation. The tg-ArcSwe model (i.e. transgenic mice with the Arctic and Swedish Alzheimer mutations) expresses elevated levels of Abeta protofibrils in the brain, making tg-ArcSwe a highly suitable model for investigating the pathogenic role of these Abeta assemblies. In the present study, we estimated Abeta protofibril levels in the brain and cerebrospinal fluid of tg-ArcSwe mice, and also assessed their role with respect to cognitive functions. Protofibril levels, specifically measured with a sandwich ELISA, were found to be elevated in young tg-ArcSwe mice compared to several transgenic models lacking the Arctic mutation. In aged tg-ArcSwe mice with considerable plaque deposition, Abeta protofibrils were approximately 50% higher than in younger mice, whereas levels of total Abeta were exponentially increased. Young tg-ArcSwe mice showed deficits in spatial learning, and individual performances in the Morris water maze were correlated inversely with levels of Abeta protofibrils, but not with total Abeta levels. We conclude that Abeta protofibrils accumulate in an age-dependent manner in tg-ArcSwe mice, although to a far lesser extent than total Abeta. Our findings suggest that increased levels of Abeta protofibrils could result in spatial learning impairment.
authors.affiliation: Department of Public Health and Caring Sciences/Molecular Geriatrics, Uppsala University, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Lord
authors.forename: Hillevi
authors.initials: H
authors.lastname: Englund
authors.forename: Linda
authors.initials: L
authors.lastname: Söderberg
authors.forename: Stina
authors.initials: S
authors.lastname: Tucker
authors.forename: Fredrik
authors.initials: F
authors.lastname: Clausen
authors.forename: Lars
authors.initials: L
authors.lastname: Hillered
authors.forename: Marcia
authors.initials: M
authors.lastname: Gordon
authors.forename: Dave
authors.initials: D
authors.lastname: Morgan
authors.forename: Lars
authors.initials: L
authors.lastname: Lannfelt
authors.forename: Frida E
authors.initials: FE
authors.lastname: Pettersson
authors.forename: Lars N G
authors.initials: LN
authors.lastname: Nilsson
mesh_terms: D000375:Aging / Q000473:pathology; D000544:Alzheimer Disease / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D016229:Amyloid beta-Peptides / Q000134:cerebrospinal fluid / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D051379:Mice; D008822:Mice, Transgenic; D009154:Mutation; D058225:Plaque, Amyloid / Q000473:pathology
chemical_list: D016229:Amyloid beta-Peptides