title: Mostly separate distributions of CLAC- versus Abeta40- or thioflavin S-reactivities in senile plaques reveal two distinct subpopulations of beta-amyloid deposits.
abstract: Collagenous Alzheimer amyloid plaque component (CLAC) is a unique non-Abeta amyloid component of senile plaques (SP) derived from a transmembrane collagen termed CLAC-precursor. Here we characterize the chronological and spatial relationship of CLAC with other features of SP amyloid in the brains of patients with Alzheimer's disease (AD), Down syndrome (DS), and of PSAPP transgenic mice. In AD and DS cerebral cortex, CLAC invariably colocalized with Abeta42 but often lacked Abeta40- or thioflavin S (thioS)-reactivities. Immunoelectron microscopy of CLAC-positive SP showed labeling of fibrils that are more loosely dispersed compared to typical amyloid fibrils in CLAC-negative SP. In DS cerebral cortex, diffuse plaques in young patients were negative for CLAC, whereas a subset of SP became CLAC-positive in patients aged 35 to 50 years, before the appearance of Abeta40. In DS cases over 50 years of age, Abeta40-positive SP dramatically increased, whereas CLAC burden remained at a constant level. In PSAPP transgenic mice, CLAC was positive in the diffuse Abeta deposits surrounding huge-cored plaques. Thus, CLAC and Abeta40 or thioS exhibit mostly separate distribution patterns in SP, suggesting that CLAC is a relatively early component of SP in human brains that may have inhibitory effects against the maturation of SP into beta-sheet-rich amyloid deposits.
authors.affiliation: Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Bunkyo-ku, Hongo, Tokyo 113-0033, Japan.
authors.forename: Hisatomo
authors.initials: H
authors.lastname: Kowa
authors.forename: Tomoko
authors.initials: T
authors.lastname: Sakakura
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Matsuura
authors.forename: Tomoko
authors.initials: T
authors.lastname: Wakabayashi
authors.forename: David M A
authors.initials: DM
authors.lastname: Mann
authors.forename: Karen
authors.initials: K
authors.lastname: Duff
authors.forename: Shoji
authors.initials: S
authors.lastname: Tsuji
authors.forename: Tadafumi
authors.initials: T
authors.lastname: Hashimoto
authors.forename: Takeshi
authors.initials: T
authors.lastname: Iwatsubo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000378:metabolism / Q000473:pathology; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D052160:Benzothiazoles; D004314:Down Syndrome / Q000378:metabolism / Q000473:pathology; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism* / Q000648:ultrastructure; D051379:Mice; D008822:Mice, Transgenic; D008875:Middle Aged; D019579:Neocortex / Q000166:cytology / Q000378:metabolism / Q000473:pathology; D009474:Neurons / Q000378:metabolism / Q000473:pathology; D024041:Non-Fibrillar Collagens; D010446:Peptide Fragments / Q000378:metabolism*; D058225:Plaque, Amyloid / Q000737:chemistry* / Q000648:ultrastructure; D013844:Thiazoles / Q000378:metabolism*; D014018:Tissue Distribution
chemical_list: D016229:Amyloid beta-Peptides; D000911:Antibodies, Monoclonal; D052160:Benzothiazoles; C456021:COL25A1 protein, human; D008565:Membrane Proteins; D024041:Non-Fibrillar Collagens; D010446:Peptide Fragments; D013844:Thiazoles; C075222:amyloid beta-protein (1-42); C090308:amyloid beta-protein (40-1); C009462:thioflavin T