Whole-mount analysis reveals normal numbers of dopaminergic neurons following misexpression of?-Synuclein inDrosophila

Pesah, Yakov; Burgess, Heather; Middlebrooks, Brooke W.; Ronningen, Kari; Prosser, Jude; Tirunagaru, Vijaya G.; Zysk, John R.; Mardon, Graeme

doi:10.1002/gene.20106

Cited by 72 publications

(60 citation statements)

References 21 publications

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“…These studies involved the use of TH immunohistochemical staining of paraffin-imbedded thin sections to document the loss of DA neurons. However, more recent studies of these same transgenic lines using confocal microscopy failed to detect loss of TH-positive neurons in any of the major DA neuron clusters in Drosophila (Auluck et al, 2005;Pesah et al, 2005). These conflicts appear to be explained by a reduction in TH expression in the PPM1 and PPM2 clusters of DA neurons in ␣-synuclein transgenic flies and improved sensitivity of the confocal methodology in detecting TH-positive neurons relative to light microscopy (Auluck et al, 2005).…”

Section: Resultsmentioning

confidence: 95%

Induction of the Phase II Detoxification Pathway Suppresses Neuron Loss inDrosophilaModels of Parkinson's Disease

Trinh¹,

Moore²,

Wes³

et al. 2008

J. Neurosci.

143

153

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␣-Synuclein aggregates are a common feature of sporadic Parkinson's disease (PD), and mutations that increase ␣-synuclein abundance confer rare heritable forms of PD. Although these findings suggest that ␣-synuclein plays a central role in the pathogenesis of this disorder, little is known of the mechanism by which ␣-synuclein promotes neuron loss or the factors that regulate ␣-synuclein toxicity. To address these matters, we tested candidate modifiers of ␣-synuclein toxicity using a Drosophila model of PD. In the current work, we focused on phase II detoxification enzymes involved in glutathione metabolism. We find that the neuronal death accompanying ␣-synuclein expression in Drosophila is enhanced by loss-of-function mutations in genes that promote glutathione synthesis and glutathione conjugation. This neuronal loss can be overcome by genetic or pharmacological interventions that increase glutathione synthesis or glutathione conjugation activity. Moreover, these same pharmacological agents suppress neuron loss in Drosophila parkin mutants, a loss-of-function model of PD. Our results suggest that oxidative stress is a feature of ␣-synuclein toxicity and that induction of the phase II detoxification pathway represents a potential preventative therapy for PD.

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Section: Resultsmentioning

confidence: 95%

Induction of the Phase II Detoxification Pathway Suppresses Neuron Loss inDrosophilaModels of Parkinson's Disease

Trinh¹,

Moore²,

Wes³

et al. 2008

J. Neurosci.

143

153

View full text Add to dashboard Cite

show abstract

“…Because previous reports (which relied on paraformaldehyde fixation of Drosophila brains followed by whole mount imaging or on paraffin sectioning before imaging) generated conflicting data sets, we concluded that a systematic comparison of the protocols developed for dopaminergic staining in Drosophila would resolve an issue that might lie at the source of inconsistency in the field (Davis et al 2003;Yang et al 2003;Pesah et al 2005;Whitworth et al 2005;Wang et al 2006). We surveyed the literature describing classical insect neuroanatomy, focusing on the characterization of aminergic peptides in the adult insect brain (DeGiusti and Ezman 1955;Seroogy et al 1988;Homberg et al 1991;Nassel and Elekes 1992).…”

Section: Resultsmentioning

confidence: 98%

An Optimized Method for Histological Detection of Dopaminergic Neurons inDrosophila melanogaster

Drobysheva

Ameel

Welch

et al. 2008

J Histochem Cytochem.

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Parkinson's disease (PD) affects >1 million Americans and is marked by the loss of dopaminergic neurons in the substantia nigra. PD has been linked to two causative factors: genetic risks (hereditary PD) and environmental toxins (idiopathic PD). In recent years, considerable effort has been devoted to the development of a Drosophila model of human PD that might be useful for examining the cellular mechanisms of PD pathology by genetic screening. In 2000, Feany and Bender reported a Drosophila model of PD in which transgenic flies expressing human mutant α-synuclein exhibited shortened life spans, dopaminergic losses, Parkinsonian behaviors, and Lewy bodies in surviving dopaminergic neurons. Since then, a number of studies have been published that validate the model or build on it; conversely, a number report an inability to replicate the results and suggest that most protocols for dopaminergic histology underreport the actual numbers of dopaminergic neurons in the insect brain. Here we report the optimization of dopaminergic histology in Drosophila and identification of new dopaminergic neurons, show the remarkable dendritic complexity of these neurons, and provide an updated count of these neurons in adult brains. This manuscript contains online supplemental material at http://www.jhc.org . Please visit this article online to view these materials.

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“…Under these conditions, we interpret the loss of tyrosine hydroxylase immunostaining we observe as loss of dopaminergic neurons. In contrast, other groups have suggested that apparently normal numbers of dopaminergic neurons reported in ␣-synuclein transgenic flies analyzed with whole-mount immunostaining techniques reflect dysfunction rather than death of these neurons (Auluck et al, 2005;Pesah et al, 2005).…”

Section: ␣-Synmentioning

confidence: 88%

Aggregated α-Synuclein Mediates Dopaminergic NeurotoxicityIn Vivo

Periquet¹,

Fulga²,

Myllykangas³

et al. 2007

J. Neurosci.

275

217

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Mutations in the synaptic protein ␣-synuclein cause rare genetic forms of Parkinson's disease. ␣-Synuclein is thought to play a critical role in more common sporadic cases of Parkinson's disease as well because the protein aggregates in the hallmark intraneuronal inclusions of the disorder, Lewy bodies. To test the role of protein aggregation in the pathogenesis of Parkinson's disease, we expressed a form of ␣-synuclein with a deletion of amino acids 71-82 that is unable to aggregate in vitro in a transgenic Drosophila model of the disorder. We found no evidence of large aggregates or oligomeric species of ␣-synuclein in these animals and no loss of tyrosine hydroxylase-positive neurons. We also expressed a truncated form of ␣-synuclein that has enhanced ability to aggregate in vitro. This truncated form of ␣-synuclein showed increased aggregation into large inclusions bodies, increased accumulation of high molecular weight ␣-synuclein species, and demonstrated enhanced neurotoxicity in vivo. Our findings thus support a critical role for aggregation of ␣-synuclein in mediating toxicity to dopaminergic neurons in vivo, although the precise role each aggregated form of ␣-synuclein plays in neurotoxicity remains to be determined.

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Whole-mount analysis reveals normal numbers of dopaminergic neurons following misexpression of?-Synuclein inDrosophila

Cited by 72 publications

References 21 publications

Induction of the Phase II Detoxification Pathway Suppresses Neuron Loss inDrosophilaModels of Parkinson's Disease

Induction of the Phase II Detoxification Pathway Suppresses Neuron Loss inDrosophilaModels of Parkinson's Disease

An Optimized Method for Histological Detection of Dopaminergic Neurons inDrosophila melanogaster

Aggregated α-Synuclein Mediates Dopaminergic NeurotoxicityIn Vivo

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