title: Brain oligomeric β-amyloid but not total amyloid plaque burden correlates with neuronal loss and astrocyte inflammatory response in amyloid precursor protein/tau transgenic mice.
abstract: It has long been assumed that β-amyloid (Aβ) had to assemble into fibrillar amyloid plaques to exert its neurotoxic effects in Alzheimer disease. An alternative hypothesis is that soluble oligomers ofAβ play a much larger role in neuronal damage than the insoluble component. We have tested these competing hypotheses in vivo by studying the clinicopathologic correlates of oligomeric Aβ species and classic fibrillar amyloid plaques in the brains of double-transgenic APP-tau mice up to 17 months of age. Biochemical and immunohistochemical measures of brain oligomeric Aβ exponentially increased with age. Oligomeric Aβ load correlated with morphological markers of fibrillar Aβ deposition. In contrast to total amyloid plaque burden, the amount of oligomeric Aβ deposits labeled by the conformational epitope-specific antibody Nab61 closely correlated with neuronal loss and numbers of astrocytes in the entorhinal cortex and the CA1 hippocampal subfield. However, like other morphological Aβ measurements, brain oligomeric Aβ burden did not correlate well with memory deficits in these mice. The number of glial fibrillary acidic protein-positive astrocytes in entorhinal cortex and CA1 most tightly correlated with memory impairment and neuronal cell loss. Based on these findings, we hypothesize that the astrocyte response, which is likely triggered by brain oligomeric Aβ accumulation, adversely affects cognition and might also contribute to neuronal cell death in this model.
authors.affiliation: Neurology Department, Massachusetts General Hospital, Harvard University, Boston, Massachusetts 02114, USA.
authors.forename: Bibiana
authors.initials: B
authors.lastname: DaRocha-Souto
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Scotton
authors.forename: Mireia
authors.initials: M
authors.lastname: Coma
authors.forename: Alberto
authors.initials: A
authors.lastname: Serrano-Pozo
authors.forename: Tadafumi
authors.initials: T
authors.lastname: Hashimoto
authors.forename: Lidia
authors.initials: L
authors.lastname: Serenó
authors.forename: Marta
authors.initials: M
authors.lastname: Rodríguez
authors.forename: Belen
authors.initials: B
authors.lastname: Sánchez
authors.forename: Bradley T
authors.initials: BT
authors.lastname: Hyman
authors.forename: Teresa
authors.initials: T
authors.lastname: Gómez-Isla
mesh_terms: D016229:Amyloid beta-Peptides / Q000378:metabolism*; D016564:Amyloid beta-Protein Precursor / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001253:Astrocytes / Q000378:metabolism* / Q000473:pathology; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D002452:Cell Count; D003214:Conditioning, Classical / Q000502:physiology; D004195:Disease Models, Animal; D005239:Fear / Q000502:physiology; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D007150:Immunohistochemistry; D007249:Inflammation / Q000378:metabolism* / Q000473:pathology; D018782:Maze Learning / Q000502:physiology; D008568:Memory / Q000502:physiology; D051379:Mice; D008822:Mice, Transgenic; D009474:Neurons / Q000378:metabolism* / Q000473:pathology; D058225:Plaque, Amyloid / Q000378:metabolism* / Q000473:pathology; D013028:Space Perception / Q000502:physiology; D016875:tau Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D005904:Glial Fibrillary Acidic Protein; D016875:tau Proteins