Co-ordinate transcriptional regulation of dopamine synthesis genes by alpha-synuclein in human neuroblastoma cell lines.
Abnormal accumulation of alpha-synuclein in Lewy bodies is a neuropathological hallmark of both sporadic and familial Parkinson's disease (PD). Although mutations in alpha-synuclein have been identified in autosomal dominant PD, the mechanism by which dopaminergic cell death occurs remains unknown. We investigated transcriptional changes in neuroblastoma cell lines transfected with either normal or mutant (A30P or A53T) alpha-synuclein using microarrays, with confirmation of selected genes by quantitative RT-PCR. Gene products whose expression was found to be significantly altered included members of diverse functional groups such as stress response, transcription regulators, apoptosis-inducing molecules, transcription factors and membrane-bound proteins. We also found evidence of altered expression of dihydropteridine reductase, which indirectly regulates the synthesis of dopamine. Because of the importance of dopamine in PD, we investigated the expression of all the known genes in dopamine synthesis. We found co-ordinated downregulation of mRNA for GTP cyclohydrolase, sepiapterin reductase (SR), tyrosine hydroxylase (TH) and aromatic acid decarboxylase by wild-type but not mutant alpha-synuclein. These were confirmed at the protein level for SR and TH. Reduced expression of the orphan nuclear receptor Nurr1 was also noted, suggesting that the co-ordinate regulation of dopamine synthesis is regulated through this transcription factor.
Baptista
Melisa J
MJ
Laboratory of Neurogenetics, National Institute on Aging/NIH, Building 10 Room 6C103, MSC 1589, 9000 Rockville Pike, Bethesda, MD 20892, USA. baptista@mail.nih.gov
O'Farrell
Casey
C
Daya
Sneha
S
Ahmad
Rili
R
Miller
David W
DW
Hardy
John
J
Farrer
Matthew J
MJ
Cookson
Mark R
MR
D000429:Alcohol Oxidoreductases / Q000235:genetics / Q000378:metabolism; D001142:Aromatic-L-Amino-Acid Decarboxylases / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004298:Dopamine / Q000096:biosynthesis*; D006136:GTP Cyclohydrolase / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D009447:Neuroblastoma / Q000737:chemistry / Q000378:metabolism*; D009474:Neurons / Q000737:chemistry / Q000166:cytology / Q000378:metabolism*; D057126:Nuclear Receptor Subfamily 4, Group A, Member 2; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000378:metabolism; D020218:Response Elements / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051843:Synucleins; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured; D014446:Tyrosine 3-Monooxygenase / Q000235:genetics / Q000378:metabolism; D051844:alpha-Synuclein
D004268:DNA-Binding Proteins; C539882:NR4A2 protein, human; D009419:Nerve Tissue Proteins; D057126:Nuclear Receptor Subfamily 4, Group A, Member 2; D012333:RNA, Messenger; C497604:SNCA protein, human; D051843:Synucleins; D014157:Transcription Factors; D051844:alpha-Synuclein; D000429:Alcohol Oxidoreductases; C022630:sepiapterin reductase; D014446:Tyrosine 3-Monooxygenase; D006136:GTP Cyclohydrolase; D001142:Aromatic-L-Amino-Acid Decarboxylases; D004298:Dopamine