Advanced

The effect of alpha-synuclein knockdown on MPP plus toxicity in models of human neurons

Fountaine, Timothy M.; Venda, Lara Lourenco; Warrick, Nicholas; Christian, Helen C.; Brundin, Patrik LU ; Channon, Keith M. and Wade-Martins, Richard (2008) In European Journal of Neuroscience 28(12). p.2459-2473
Abstract
The protein alpha-synuclein is central to the pathophysiology of Parkinson's disease (PD) but its role in the development of neurodegeneration remains unclear. alpha-Synuclein-knockout mice develop without gross abnormality and are resistant to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a mitochondrial inhibitor widely used to model parkinsonism. Here we show that differentiated human dopaminergic neuron-like cells also have increased resistance to 1-methyl-4-phenylpyridine (MPP+), the active metabolite of MPTP, when alpha-synuclein is knocked down using RNA interference. In attempting to understand how this occurred we found that lowering alpha-synuclein levels caused changes to intracellular vesicles, dopamine transporter (DAT)... (More)
The protein alpha-synuclein is central to the pathophysiology of Parkinson's disease (PD) but its role in the development of neurodegeneration remains unclear. alpha-Synuclein-knockout mice develop without gross abnormality and are resistant to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a mitochondrial inhibitor widely used to model parkinsonism. Here we show that differentiated human dopaminergic neuron-like cells also have increased resistance to 1-methyl-4-phenylpyridine (MPP+), the active metabolite of MPTP, when alpha-synuclein is knocked down using RNA interference. In attempting to understand how this occurred we found that lowering alpha-synuclein levels caused changes to intracellular vesicles, dopamine transporter (DAT) and vesicular monoamine transporter (VMAT2), each of which is known to be an important component of the early events leading to MPP+ toxicity. Knockdown of alpha-synuclein reduced the availability of DAT on the neuronal surface by 50%, decreased the total number of intracellular vesicles by 37% but increased the density of VMAT2 molecules per vesicle by 2.8-fold. However, these changes were not associated with any reduction in MPP+-induced superoxide production, suggesting that alpha-synuclein knockdown may have other downstream effects which are important. We then showed that alpha-synuclein knockdown prevented MPP+-induced activation of nitric oxide synthase (NOS). Activation of NOS is an essential step in MPTP toxicity and increasing evidence points to nitrosative stress as being important in neurodegeneration. Overall, these results show that as well as having a number of effects on cellular events upstream of mitochondrial dysfunction alpha-synuclein affects pathways downstream of superoxide production, possibly involving regulation of NOS activity. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
nitric oxide synthase, MPP, interference, vesicular monoamine transporter 2, RNA, dopamine transporter, alpha-synuclein
in
European Journal of Neuroscience
volume
28
issue
12
pages
2459 - 2473
publisher
Wiley-Blackwell
external identifiers
  • wos:000261625800012
  • scopus:57449096338
ISSN
1460-9568
DOI
10.1111/j.1460-9568.2008.06527.x
language
English
LU publication?
yes
id
e77ced09-90a6-44e8-ae33-7f3423f7e3bc (old id 1305662)
date added to LUP
2009-03-23 12:07:43
date last changed
2017-11-05 03:32:41
@article{e77ced09-90a6-44e8-ae33-7f3423f7e3bc,
  abstract     = {The protein alpha-synuclein is central to the pathophysiology of Parkinson's disease (PD) but its role in the development of neurodegeneration remains unclear. alpha-Synuclein-knockout mice develop without gross abnormality and are resistant to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a mitochondrial inhibitor widely used to model parkinsonism. Here we show that differentiated human dopaminergic neuron-like cells also have increased resistance to 1-methyl-4-phenylpyridine (MPP+), the active metabolite of MPTP, when alpha-synuclein is knocked down using RNA interference. In attempting to understand how this occurred we found that lowering alpha-synuclein levels caused changes to intracellular vesicles, dopamine transporter (DAT) and vesicular monoamine transporter (VMAT2), each of which is known to be an important component of the early events leading to MPP+ toxicity. Knockdown of alpha-synuclein reduced the availability of DAT on the neuronal surface by 50%, decreased the total number of intracellular vesicles by 37% but increased the density of VMAT2 molecules per vesicle by 2.8-fold. However, these changes were not associated with any reduction in MPP+-induced superoxide production, suggesting that alpha-synuclein knockdown may have other downstream effects which are important. We then showed that alpha-synuclein knockdown prevented MPP+-induced activation of nitric oxide synthase (NOS). Activation of NOS is an essential step in MPTP toxicity and increasing evidence points to nitrosative stress as being important in neurodegeneration. Overall, these results show that as well as having a number of effects on cellular events upstream of mitochondrial dysfunction alpha-synuclein affects pathways downstream of superoxide production, possibly involving regulation of NOS activity.},
  author       = {Fountaine, Timothy M. and Venda, Lara Lourenco and Warrick, Nicholas and Christian, Helen C. and Brundin, Patrik and Channon, Keith M. and Wade-Martins, Richard},
  issn         = {1460-9568},
  keyword      = {nitric oxide synthase,MPP,interference,vesicular monoamine transporter 2,RNA,dopamine transporter,alpha-synuclein},
  language     = {eng},
  number       = {12},
  pages        = {2459--2473},
  publisher    = {Wiley-Blackwell},
  series       = {European Journal of Neuroscience},
  title        = {The effect of alpha-synuclein knockdown on MPP plus toxicity in models of human neurons},
  url          = {http://dx.doi.org/10.1111/j.1460-9568.2008.06527.x},
  volume       = {28},
  year         = {2008},
}