title: Sirtuin 1 reduction parallels the accumulation of tau in Alzheimer disease.
abstract: Aging and metabolism-related disorders are risk factors for Alzheimer disease (AD). Because sirtuins may increase the life span through regulation of cellular metabolism, we compared the concentration of sirtuin 1 (SIRT1) in the brains of AD patients (n = 19) and controls (n = 22) using Western immunoblots and in situ hybridization. We report a significant reduction of SIRT1 (messenger RNA [mRNA], -29%; protein, -45%) in the parietal cortex of AD patients, but not in the cerebellum. Further analyses in a second cohort of 36 subjects confirmed that cortical SIRT1 was decreased in AD but not in individuals with mild cognitive impairment. SIRT1 mRNA and its translated protein correlated negatively with the duration of symptoms (mRNA, r2 = -0.367; protein, r2 = -0.326) and the accumulation of paired helical filament tau (mRNA, r2 = -0.230; protein, r2 = -0.119), but weakly with insoluble amyloid-beta 42 (mRNA, r2= -0.090; protein, r2 = -0.072). A significant relationship between SIRT1 levels and global cognition scores proximate to death was also found (r2= +0.09, p = 0.049). In contrast, cortical SIRT1 levels remained unchanged in a triple-transgenic animal model of AD. Collectively, our results indicate that loss of SIRT1 is closely associated with the accumulation of amyloid-beta and tau in the cerebral cortex of persons with AD.
authors.affiliation: Faculty of Pharmacy, Laval University, Centre Hospitalier de l'Université Laval Research Center, Quebec, Quebec, Canada.
authors.forename: Carl
authors.initials: C
authors.lastname: Julien
authors.forename: Cyntia
authors.initials: C
authors.lastname: Tremblay
authors.forename: Vincent
authors.initials: V
authors.lastname: Emond
authors.forename: Meryem
authors.initials: M
authors.lastname: Lebbadi
authors.forename: Norman
authors.initials: N
authors.lastname: Salem
authors.forename: David A
authors.initials: DA
authors.lastname: Bennett
authors.forename: Frédéric
authors.initials: F
authors.lastname: Calon
mesh_terms: D000367:Age Factors; D000368:Aged; D000544:Alzheimer Disease / Q000378:metabolism* / Q000473:pathology; D016229:Amyloid beta-Peptides / Q000235:genetics / Q000378:metabolism; D016564:Amyloid beta-Protein Precursor / Q000235:genetics; D000704:Analysis of Variance; D000818:Animals; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000378:metabolism; D002849:Chromatography, Gas / Q000379:methods; D015331:Cohort Studies; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology*; D006801:Humans; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D008875:Middle Aged; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D056564:Sirtuin 1; D037761:Sirtuins / Q000235:genetics / Q000378:metabolism*; D013223:Statistics as Topic; D016875:tau Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D010446:Peptide Fragments; D012333:RNA, Messenger; C075222:amyloid beta-protein (1-42); D016875:tau Proteins; C447939:SIRT1 protein, human; D056564:Sirtuin 1; D037761:Sirtuins