title: Identification of polypeptides in neurofibrillary tangles and total homogenates of brains with Alzheimer's disease by tandem mass spectrometry.
abstract: Alzheimer's disease (AD) is the most common cause of dementia in the elderly. AD brains are characterized by the presence of neurofibrillary tangles (NFTs) and neuritic plaques. NFTs are constituted of paired helical filaments, which are structurally composed by assembled hyperphosphorylated and truncated tau polypeptides. To date, the integral constituents of NFTs remain unknown mainly due to the high insolubility of NFTs. The aim of this study was to identify by tandem mass spectrometry, the polypeptides contained in both isolated NFTs by laser capture microdissection and total homogenates, using tissue sections from paraformaldehyde-fixed AD brains. In the first case, we isolated 2,000 NFTs from tissue samples of hippocampus from each of the three Mexican AD brains used in our study. These were previously stained with anti-hyperphosphorylated tau AT-100 antibodies. After the removal of paraformaldehyde and delipidation with organic solvents, we tested three solubilization methods. We identified 102 polypeptides from total homogenates and 41 from isolated NFTs. We selected UCH-L1, transferrin, and GAPDH polypeptides to be studied by immunofluorescence and confocal microscopy. Only UCH-L1 and GAPDH colocalized with hyperphosphorylated tau in NFTs.
authors.affiliation: Departamento de Biología Celular, Cinvestav-IPN, Col. San Pedro Zacatenco, México, D.F., México.
authors.forename: Benito
authors.initials: B
authors.lastname: Minjarez
authors.forename: María Luz
authors.initials: ML
authors.lastname: Valero Rustarazo
authors.forename: Manuel M
authors.initials: MM
authors.lastname: Sanchez del Pino
authors.forename: Arturo
authors.initials: A
authors.lastname: González-Robles
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Sosa-Melgarejo
authors.forename: Jose
authors.initials: J
authors.lastname: Luna-Muñoz
authors.forename: Raul
authors.initials: R
authors.lastname: Mena
authors.forename: Juan Pedro
authors.initials: JP
authors.lastname: Luna-Arias
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000473:pathology*; D001921:Brain / Q000378:metabolism* / Q000648:ultrastructure; D002851:Chromatography, High Pressure Liquid; D019295:Computational Biology; D005260:Female; D006801:Humans; D061346:Laser Capture Microdissection; D008297:Male; D046529:Microscopy, Electron, Transmission; D016874:Neurofibrillary Tangles / Q000378:metabolism* / Q000648:ultrastructure; D010455:Peptides / Q000378:metabolism*; D053719:Tandem Mass Spectrometry
chemical_list: D010455:Peptides