title: beta-site amyloid precursor protein cleaving enzyme 1 increases amyloid deposition in brain parenchyma but reduces cerebrovascular amyloid angiopathy in aging BACE x APP[V717I] double-transgenic mice.
abstract: The generation of amyloid peptides (Abeta) from the amyloid precursor protein (APP) is initiated by beta-secretase (BACE), whereas subsequent gamma-secretase cleavage mediated by presenilin-1, produces Abeta peptides mainly of 40 or 42 amino acids long. In addition, alternative beta'-cleavage of APP at position 11 of the amyloid sequence results in N-truncated Abeta(11-40/42) peptides, but the functional significance or pathological impact is unknown. Here we demonstrate that in the brain of BACE x APP[V717I] double-transgenic mice, amyloidogenic processing at both Asp1 and Glu11 is increased resulting in more and different Abeta species and APP C-terminal fragments. Pathologically, BACE significantly increased the number of diffuse and senile amyloid plaques in old double-transgenic mice. Unexpectedly, vascular amyloid deposition was dramatically lower in the same BACE x APP[V717I] double-transgenic mice, relative to sex- and age-matched APP[V717I] single-transgenic mice in the same genetic background. The tight inverse relation of vascular amyloid to the levels of the less soluble N-terminally truncated Abeta peptides is consistent with the hypothesis that vascular amyloid deposition depends on drainage of excess tissue Abeta. This provides biochemical evidence in vivo for the preferential contribution of N-truncated Abeta to parenchymal amyloid deposition in contrast to vascular amyloid pathology.
authors.affiliation: Experimental Genetics Group, LEGT_EGG, K.U. Leuven, Campus Gasthuisberg O and N 06, B-3000, Leuven, Belgium.
authors.forename: Michael
authors.initials: M
authors.lastname: Willem
authors.forename: Ilse
authors.initials: I
authors.lastname: Dewachter
authors.forename: Neil
authors.initials: N
authors.lastname: Smyth
authors.forename: Tom
authors.initials: T
authors.lastname: Van Dooren
authors.forename: Peter
authors.initials: P
authors.lastname: Borghgraef
authors.forename: Christian
authors.initials: C
authors.lastname: Haass
authors.forename: Fred
authors.initials: F
authors.lastname: Van Leuven
mesh_terms: D000367:Age Factors; D000682:Amyloid / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D053829:Amyloid Precursor Protein Secretases; D016564:Amyloid beta-Protein Precursor / Q000235:genetics / Q000502:physiology; D000818:Animals; D016282:Aspartic Acid Endopeptidases; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D016657:Cerebral Amyloid Angiopathy / Q000473:pathology; D002540:Cerebral Cortex / Q000473:pathology; D010450:Endopeptidases / Q000235:genetics / Q000502:physiology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005838:Genotype; D007150:Immunohistochemistry; D016014:Linear Models; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009474:Neurons / Q000473:pathology; D010455:Peptides / Q000737:chemistry; D012737:Sex Factors
chemical_list: D000682:Amyloid; D016564:Amyloid beta-Protein Precursor; D010455:Peptides; D053829:Amyloid Precursor Protein Secretases; D010450:Endopeptidases; D016282:Aspartic Acid Endopeptidases; C509282:Bace1 protein, mouse