Effect of mutant alpha-synuclein on dopamine homeostasis in a new human mesencephalic cell line.
Författare
Summary, in English
Mutations in alpha-synuclein have been linked to rare, autosomal dominant forms of Parkinsons disease. Despite its ubiquitous expression, mutant alpha-synuclein primarily leads to the loss of dopamine-producing neurons in the substantia nigra. Alpha-synuclein is a presynaptic nerve terminal protein of unknown function, though some studies suggest it is important for synapse formation and maintenance. The present study utilized a new human mesencephalic cell line, MESC2.10, to study the effect of A53T mutant alpha-synuclein on dopamine homeostasis. In addition to expressing markers of mature dopamine neurons, differentiated MESC2.10 cells are electrically active, produce dopamine, and express wild-type human alpha-synuclein. Lentivirus-induced overexpression of A53T mutant alpha-synuclein in differentiated MESC2.10 cells resulted in downregulation of the vesicular dopamine transporter (VMAT2), decreased potassium-induced and increased amphetamine-induced dopamine release, enhanced cytoplasmic dopamine immunofluorescence, and increased intracellular levels of superoxide. These results suggest that mutant alpha-synuclein leads to an impairment in vesicular dopamine storage and consequent accumulation of dopamine in the cytosol, a pathogenic mechanism that underlies the toxicity of the psychostimulant amphetamine and the parkinsonian neurotoxin 1-methyl-4-phenylpyridinium. Interestingly, cells expressing A53T mutant alpha-synuclein were resistant to amphetamine-induced toxicity. Since extra-vesicular, cytoplasmic dopamine can be easily oxidized into reactive oxygen species and other toxic metabolites, mutations in alpha-synuclein might lead to Parkinsons disease by triggering protracted, low-grade dopamine toxicity resulting in terminal degeneration and ultimately cell death.
Avdelning/ar
- Institutionen för experimentell medicinsk vetenskap
- Islet cell physiology
Publiceringsår
2002
Språk
Engelska
Sidor
38884-38894
Publikation/Tidskrift/Serie
Journal of Biological Chemistry
Volym
277
Issue
41
Fulltext
- Available as PDF - 554 kB
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Länkar
Dokumenttyp
Artikel i tidskrift
Förlag
American Society for Biochemistry and Molecular Biology
Ämne
- Cell and Molecular Biology
Status
Published
Forskningsgrupp
- Islet cell physiology
ISBN/ISSN/Övrigt
- ISSN: 1083-351X