title: Analysis of alpha-synuclein, dopamine and parkin pathways in neuropathologically confirmed parkinsonian nigra.
abstract: The identification of mutations that cause familial Parkinson's disease (PD) provides a framework for studies into pathways that may be perturbed also in the far more common, non-familial form of the disorder. Following this hypothesis, we have examined the gene regulatory network that links alpha-synuclein and parkin pathways with dopamine metabolism in neuropathologically verified cases of sporadic PD. By means of an in silico approach using a database of eukaryotic molecular interactions and a whole genome transcriptome dataset validated by qRT-PCR and histological methods, we found parkin and functionally associated genes to be up-regulated in the lateral substantia nigra (SN). In contrast, alpha-synuclein and ubiquitin carboxyl-terminal hydrolase L1 (UCHL1) gene expression levels were significantly reduced in both the lateral and medial SN in PD. Gene expression for Septin 4, a member of the GTP-binding protein family involved in alpha-synuclein metabolism was elevated in the lateral parkinsonian SN. Additionally, catalase and mitogen-activated protein kinase 8 and poly(ADP-ribose) polymerase family member 1 (PARP1) known to function in DNA repair and cell death induction, all members of the dopamine synthesis pathway, were up-regulated in the lateral SN. In contrast, two additional PD-linked genes, glucocerebrosidase and nuclear receptor subfamily 4, group A, member 2 (NR4A2) showed reduced expression. We show that in sporadic PD, parkin, alpha-synuclein and dopamine pathways are co-deregulated. Alpha-synuclein is a member of all three gene regulatory networks. Our analysis results support the view that alpha-synuclein has a central role in the familial as well as the non-familial form of the disease and provide steps towards a pathway definition of PD.
authors.affiliation: University Department of Neuropathology, Faculty of Medicine, Division of Neuroscience and Mental Health, Imperial College London and Hammersmith Hospitals Trust, Charing Cross campus, Fulham Palace Road, W6 8RF, London, UK.
authors.forename: L B
authors.initials: LB
authors.lastname: Moran
authors.forename: E
authors.initials: E
authors.lastname: Croisier
authors.forename: D C
authors.initials: DC
authors.lastname: Duke
authors.forename: M E
authors.initials: ME
authors.lastname: Kalaitzakis
authors.forename: F
authors.initials: F
authors.lastname: Roncaroli
authors.forename: M
authors.initials: M
authors.lastname: Deprez
authors.forename: D T
authors.initials: DT
authors.lastname: Dexter
authors.forename: R K B
authors.initials: RK
authors.lastname: Pearce
authors.forename: M B
authors.initials: MB
authors.lastname: Graeber
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004298:Dopamine / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D008297:Male; D046228:Microarray Analysis / Q000379:methods; D008875:Middle Aged; D008954:Models, Biological; D020734:Parkinsonian Disorders / Q000378:metabolism* / Q000473:pathology*; D015398:Signal Transduction; D013378:Substantia Nigra / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*; D051844:alpha-Synuclein / Q000235:genetics / Q000378:metabolism*
chemical_list: D051844:alpha-Synuclein; D044767:Ubiquitin-Protein Ligases; C111567:parkin protein; D004298:Dopamine