title: Upregulation of select rab GTPases in cholinergic basal forebrain neurons in mild cognitive impairment and Alzheimer's disease.
abstract: Endocytic system dysfunction is one of the earliest disturbances that occur in Alzheimer's disease (AD), and may underlie the selective vulnerability of cholinergic basal forebrain (CBF) neurons during the progression of dementia. Herein we report that genes regulating early and late endosomes are selectively upregulated within CBF neurons in mild cognitive impairment (MCI) and AD. Specifically, upregulation of rab4, rab5, rab7, and rab27 was observed in CBF neurons microdissected from postmortem brains of individuals with MCI and AD compared to age-matched control subjects with no cognitive impairment (NCI). Upregulated expression of rab4, rab5, rab7, and rab27 correlated with antemortem measures of cognitive decline in individuals with MCI and AD. qPCR validated upregulation of these select rab GTPases within microdissected samples of the basal forebrain. Moreover, quantitative immunoblot analysis demonstrated upregulation of rab5 protein expression in the basal forebrain of subjects with MCI and AD. The elevation of rab4, rab5, and rab7 expression is consistent with our recent observations in CA1 pyramidal neurons in MCI and AD. These findings provide further support that endosomal pathology accelerates endocytosis and endosome recycling, which may promote aberrant endosomal signaling and neurodegeneration throughout the progression of AD.
authors.affiliation: Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY 10962, USA. ginsberg@nki.rfmh.org
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Ginsberg
authors.forename: Elliott J
authors.initials: EJ
authors.lastname: Mufson
authors.forename: Melissa J
authors.initials: MJ
authors.lastname: Alldred
authors.forename: Scott E
authors.initials: SE
authors.lastname: Counts
authors.forename: Joanne
authors.initials: J
authors.lastname: Wuu
authors.forename: Ralph A
authors.initials: RA
authors.lastname: Nixon
authors.forename: Shaoli
authors.initials: S
authors.lastname: Che
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000201:enzymology* / Q000503:physiopathology; D020532:Basal Nucleus of Meynert / Q000201:enzymology* / Q000503:physiopathology; D059329:Cholinergic Neurons / Q000201:enzymology*; D060825:Cognitive Dysfunction / Q000201:enzymology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D015854:Up-Regulation / Q000502:physiology*; D020691:rab GTP-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D000075745:rab27 GTP-Binding Proteins; D020695:rab4 GTP-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D020696:rab5 GTP-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D000090802:rab7 GTP-Binding Proteins
chemical_list: D000075745:rab27 GTP-Binding Proteins; D000090802:rab7 GTP-Binding Proteins; C000716463:rab7 GTP-binding proteins, human; C066694:RAB27A protein, human; D020691:rab GTP-Binding Proteins; D020695:rab4 GTP-Binding Proteins; D020696:rab5 GTP-Binding Proteins