title: α-Synuclein mRNA and soluble α-synuclein protein levels in post-mortem brain from patients with Parkinson's disease, dementia with Lewy bodies, and Alzheimer's disease.
abstract: α-Synuclein is a neuronal protein implicated in the etiology of Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Whilst increased α-synuclein expression due to gene duplication or triplication can cause familial PD, previous studies of α-synuclein levels in idiopathic disease have produced conflicting data. We quantified α-synuclein mRNA and soluble protein in five human post-mortem brain regions from four groups of individuals with PD, DLB, Alzheimer's disease (AD) and matched controls. α-Synuclein mRNA levels, measured using quantitative real-time PCR, did not differ significantly between groups in any brain regions examined. In contrast, levels of soluble α-synuclein protein, measured by ELISA, were significantly lower in 4 of the 5 regions for patients with DLB, and in 2 of the 5 regions for patients with PD, compared to controls. Soluble α-synuclein protein levels were not significantly different in the AD patients, compared to controls, in 4 of the 5 regions. This study indicates that although levels of soluble α-synuclein protein are lower in DLB and PD, there is no evidence for a corresponding decrease in α-synuclein mRNA levels. This might result from altered translation, or removal of α-synuclein protein from a soluble detectable state, either by turnover or conversion to an insoluble form.
authors.affiliation: Centre for Public Health, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, N. Ireland, UK.
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Quinn
authors.forename: David T R
authors.initials: DT
authors.lastname: Coulson
authors.forename: Simon
authors.initials: S
authors.lastname: Brockbank
authors.forename: Nancy
authors.initials: N
authors.lastname: Beyer
authors.forename: Rivka
authors.initials: R
authors.lastname: Ravid
authors.forename: Jan
authors.initials: J
authors.lastname: Hellemans
authors.forename: G Brent
authors.initials: GB
authors.lastname: Irvine
authors.forename: Janet A
authors.initials: JA
authors.lastname: Johnston
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000473:pathology*; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D020961:Lewy Body Disease / Q000473:pathology*; D008297:Male; D010300:Parkinson Disease / Q000473:pathology*; D011180:Postmortem Changes; D012333:RNA, Messenger / Q000378:metabolism*; D051844:alpha-Synuclein / Q000235:genetics* / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D051844:alpha-Synuclein