title: Intraneuronal amyloid beta and reduced brain volume in a novel APP T714I mouse model for Alzheimer's disease.
abstract: Transgenic mouse models of Alzheimer's disease (AD) expressing high levels of amyloid precursor protein (APP) with familial AD (FAD) mutations have proven to be extremely useful in understanding pathogenic processes of AD especially those that involve amyloidogenesis. We earlier described Austrian APP T714I pathology that leads to one of the earliest AD age-at-onsets with abundant intracellular and extracellular amyloid deposits in brain. The latter strikingly was non-fibrillar diffuse amyloid, composed of N-truncated A beta 42 in absence of A beta 40. In vitro, this mutation leads to one of the highest A beta 42/A beta 40 ratios among all FAD mutations. We generated an APP T714I transgenic mouse model that despite having 10 times lower transgene than endogenous murine APP deposited intraneuronal A beta in brain by 6 months of age. Accumulations increased with age, and this was paralleled by decreased brain sizes on volumetric MRI, compared to age-matched and similar transgene-expressing APP wild-type mice, although, with these levels of transgenic expression we did not detect neuronal loss or significant memory impairment. Immunohistochemical studies revealed that the majority of the intraneuronal A beta deposits colocalized with late endosomal markers, although some A beta inclusions were also positive for lysosomal and Golgi markers. These data support earlier observations of A beta accumulation in the endosomal-lysosomal pathway and the hypothesis that intraneuronal accumulation of A beta could be an important factor in the AD pathogenesis.
authors.affiliation: Neurodegenerative Brain Diseases Group, Department of Molecular Genetics, VIB, Universiteitsplein 1, BE-2610 Antwerpen, Belgium.
authors.forename: Bianca
authors.initials: B
authors.lastname: Van Broeck
authors.forename: Greet
authors.initials: G
authors.lastname: Vanhoutte
authors.forename: Daniel
authors.initials: D
authors.lastname: Pirici
authors.forename: Debby
authors.initials: D
authors.lastname: Van Dam
authors.forename: Hans
authors.initials: H
authors.lastname: Wils
authors.forename: Ivy
authors.initials: I
authors.lastname: Cuijt
authors.forename: Krist'l
authors.initials: K
authors.lastname: Vennekens
authors.forename: Monika
authors.initials: M
authors.lastname: Zabielski
authors.forename: Andrej
authors.initials: A
authors.lastname: Michalik
authors.forename: Jessie
authors.initials: J
authors.lastname: Theuns
authors.forename: Peter Paul
authors.initials: PP
authors.lastname: De Deyn
authors.forename: Annemie
authors.initials: A
authors.lastname: Van der Linden
authors.forename: Christine
authors.initials: C
authors.lastname: Van Broeckhoven
authors.forename: Samir
authors.initials: S
authors.lastname: Kumar-Singh
mesh_terms: D000544:Alzheimer Disease / Q000235:genetics / Q000473:pathology* / Q000503:physiopathology; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D016564:Amyloid beta-Protein Precursor / Q000235:genetics*; D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D001921:Brain / Q000473:pathology*; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007532:Isoleucine / Q000235:genetics*; D008279:Magnetic Resonance Imaging; D018782:Maze Learning / Q000502:physiology; D051379:Mice; D008822:Mice, Transgenic; D009474:Neurons / Q000166:cytology; D010446:Peptide Fragments / Q000378:metabolism; D011597:Psychomotor Performance / Q000502:physiology; D014443:Tyrosine / Q000235:genetics*
chemical_list: D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D010446:Peptide Fragments; C078592:amyloid beta-protein (1-40); C075222:amyloid beta-protein (1-42); D007532:Isoleucine; D014443:Tyrosine