Dataset Information

Upregulating ?-hexosaminidase activity in rodents prevents ?-synuclein lipid associations and protects dopaminergic neurons from ?-synuclein-mediated neurotoxicity.

ABSTRACT: Sandhoff disease (SD) is a lysosomal storage disease, caused by loss of ?-hexosaminidase (HEX) activity resulting in the accumulation of ganglioside GM2. There are shared features between SD and Parkinson's disease (PD). ?-synuclein (aSYN) inclusions, the diagnostic hallmark sign of PD, are frequently found in the brain in SD patients and HEX knockout mice, and HEX activity is reduced in the substantia nigra in PD. In this study, we biochemically demonstrate that HEX deficiency in mice causes formation of high-molecular weight (HMW) aSYN and ubiquitin in the brain. As expected from HEX enzymatic function requirements, overexpression in vivo of HEXA and B combined, but not either of the subunits expressed alone, increased HEX activity as evidenced by histochemical assays. Biochemically, such HEX gene expression resulted in increased conversion of GM2 to its breakdown product GM3. In a neurodegenerative model of overexpression of aSYN in rats, increasing HEX activity by AAV6 gene transfer in the substantia nigra reduced aSYN embedding in lipid compartments and rescued dopaminergic neurons from degeneration. Overall, these data are consistent with a paradigm shift where lipid abnormalities are central to or preceding protein changes typically associated with PD.

SUBMITTER: Brekk OR

PROVIDER: S-EPMC7409708 | biostudies-literature | 2020 Aug

REPOSITORIES: biostudies-literature

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Upregulating β-hexosaminidase activity in rodents prevents α-synuclein lipid associations and protects dopaminergic neurons from α-synuclein-mediated neurotoxicity.

Brekk Oeystein R OR Korecka Joanna A JA Crapart Cecile C CC Huebecker Mylene M MacBain Zachary K ZK Rosenthal Sara Ann SA Sena-Esteves Miguel M Priestman David A DA Platt Frances M FM Isacson Ole O Hallett Penelope J PJ

Acta neuropathologica communications 20200806 1

Sandhoff disease (SD) is a lysosomal storage disease, caused by loss of β-hexosaminidase (HEX) activity resulting in the accumulation of ganglioside GM2. There are shared features between SD and Parkinson's disease (PD). α-synuclein (aSYN) inclusions, the diagnostic hallmark sign of PD, are frequently found in the brain in SD patients and HEX knockout mice, and HEX activity is reduced in the substantia nigra in PD. In this study, we biochemically demonstrate that HEX deficiency in mice causes fo ...[more]

PMID: 32762772

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Project description:Alpha-synuclein pathology is associated with dopaminergic neuronal loss in the substantia nigra (SN) of Parkinson's patients. Working across human and mouse models, we investigated mechanisms by which the accumulation of soluble α-synuclein oligomers leads to neurodegeneration. Biochemical analysis of the midbrain of α-synuclein overexpressing BAC-transgenic male and female mice revealed age- and region-dependent mitochondrial dysfunction and accumulation of damaged proteins downstream of the RE1 Silencing Transcription Factor (REST). Vulnerable SN dopaminergic neurons displayed low REST levels compared with neighboring protected SN GABAergic neurons, which correlated with the accumulation of α-synuclein oligomers and disrupted mitochondrial morphology. Consistent with a protective role, REST levels were reduced in patient induced pluripotent stem cell-derived dopaminergic neurons carrying the SNCA-Triplication mutation, which accumulated α-synuclein oligomers and mitochondrial damage, and displayed REST target gene dysregulation. Furthermore, CRISPR-mediated REST KO induced mitochondrial dysfunction and impaired mitophagy in vitro Conversely, REST overexpression attenuated mitochondrial toxicity and mitochondrial morphology disruption through the transcription factor PGC-1α. Finally, decreased α-synuclein oligomer accumulation and mitochondrial dysfunction in mice correlated with nuclear REST and PGC-1α in protected SN GABAergic neurons compared with vulnerable dopaminergic neurons. Our findings show that increased levels of α-synuclein oligomers cause dopaminergic neuronal-specific dysfunction through mitochondrial toxicity, which can be attenuated by REST in an early model of Parkinsonian pathology. These findings highlight REST as a mediator of dopaminergic vulnerability in PD.SIGNIFICANCE STATEMENT Understanding early Parkinsonian pathophysiology through studies of advanced preclinical models is fundamental to the translation of disease-modifying therapies. Here we show disease-relevant levels of α-synuclein expression in mice leads to accumulation of α-synuclein oligomers in the absence of overt aggregation, and mitochondrial dysfunction in dopaminergic neurons lacking the RE1 Silencing Transcription Factor. Our findings identify the mechanism of action of RE1 Silencing Transcription Factor and PGC-1α as mediators of dopaminergic vulnerability in α-synuclein BAC-transgenic mice and induced pluripotent stem cell-derived dopaminergic cultures, highlighting their potential as therapeutic targets.

Dataset Information

Upregulating ?-hexosaminidase activity in rodents prevents ?-synuclein lipid associations and protects dopaminergic neurons from ?-synuclein-mediated neurotoxicity.

Publications

Upregulating β-hexosaminidase activity in rodents prevents α-synuclein lipid associations and protects dopaminergic neurons from α-synuclein-mediated neurotoxicity.

Similar Datasets

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