Parkinson-associated SNCA enhancer variants revealed by open chromatin in mouse dopamine neurons
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE122450 | GEO | 2018/11/14
REPOSITORIES: GEO
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Project description:Parkinson’s disease (PD) is a prevalent neurodegenerative disorder that is characterized by the selective loss of midbrain dopamine (DA)-producing neurons and the formation of α-synuclein (α-syn)-containing inclusions named Lewy bodies (LBs). Here, we report that the loss of glucocerebrosidase (GCase), coupled with α-syn overexpression, result in substantial accumulation of detergent-resistant α-syn aggregates and Lewy body-like inclusions (LBLIs) in human midbrain-like organoids (hMLOs). These LBLIs exhibit a highly similar structure to PD-associated LBs, by displaying a spherically symmetric morphology with an eosinophilic core, and containing α-syn and ubiquitin. Importantly, hMLOs generated from PD patient-derived inducible pluripotent stem cells (iPSCs) harboring SNCA triplication also exhibit subsequent degeneration of DA neurons and LBLI formation upon chronic GCase inhibitor treatment. Taken together, our hMLOs harbouring two major PD risk factors (GCase deficiency and overproduced α-syn) successfully recapitulate major pathophysiological signatures of the disease, and highlight the broad utility of brain organoid technology in modeling human neurodegenerative diseases.
2021-08-13 | E-MTAB-7302 | biostudies-arrayexpress
Project description:Genome-wide association studies (GWAS) have identified genomic loci associated with complex diseases but mechanistic insights are impeded by the lack of understanding of how specific risk variants functionally contribute to diseases. Here we describe an experimental strategy to robustly identify cis-acting effects of genetic variants in regulatory elements on gene expression by combining genome-wide epigenetic information with CRISPR/Cas genome editing in human pluripotent cells. Using this genetically controlled system, we identify a common Parkinson’s disease (PD)-associated risk variant in a non-coding distal enhancer element that regulates the expression of SNCA, a key gene implicated in the pathogenesis of PD. We provide data suggesting that the transcriptional deregulation of SNCA is associated with sequence-dependent binding of the brain-specific transcription factors EMX2 and NKX6-1. Our work provides a general experimental strategy to functionally connect genetic variation with disease relevant phenotypes.
2016-04-20 | GSE71278 | GEO
Project description:Parkinsonâs disease (PD), the second most frequent neurodegenerative disorder at old age, can be caused by elevated expression, or the A53T mutation, of the presynaptic protein alpha-synuclein (SNCA). PD is characterized pathologically by the preferential vulnerability of the dopaminergic nigrostriatal projection neurons. Here, we used two mouse lines overexpressing human A53T-SNCA around ages 6 and 18 months and studied striatal dysfunction in the absence of neurodegeneration to understand early disease mechanisms. High pressure liquid chromatography analysis of striatal neurotransmitter content demonstrated that dopamine (DA) levels correlated directly with the level of expression of SNCA, an observation also observed in SNCA deficient mice. In the striatum of aged A53TSNCA overexpressing mice, where DA levels were elevated, a paradoxical upregulation of dopamine receptors DRD1A and DRD2 was detected by immunoblots and autoradiography, findings compatible with the notion of abnormal vesicle release. Extensive transcriptome studies via microarrays and quantitative real-time RT-PCR validation of altered Homer1, Cb1, Atf2 and Pde7b transcript levels indicated a progressive reduction in the postsynaptic DA response. As functional consequences, long term depression was absent in corticostriatal slices from aged transgenic mice and an insidious decrease of spontaneous locomotor activity of these animals was found in open field tests. Taken together, the dysfunctional neurotransmission and decreased synaptic plasticity seen in the A53T-SNCA overexpressing mice reflects early functional changes within the basal ganglia resulting from synucleinopathy prior to frank neurodegeneration. Thus, preclinical stages of PD may be modeled in this mouse. Parkinsonâs disease (PD), the second most frequent neurodegenerative disorder at old age, can be caused by elevated expression, or the A53T mutation, of the presynaptic protein alpha-synuclein (SNCA). PD is characterized pathologically by the preferential vulnerability of the dopaminergic nigrostriatal projection neurons. Here, we used two mouse lines overexpressing human A53T-SNCA around ages 6 and 18 months and studied striatal dysfunction in the absence of neurodegeneration to understand early disease mechanisms. High pressure liquid chromatography analysis of striatal neurotransmitter content demonstrated that dopamine (DA) levels correlated directly with the level of expression of SNCA, an observation also observed in SNCA deficient mice. In the striatum of aged A53TSNCA overexpressing mice, where DA levels were elevated, a paradoxical upregulation of dopamine receptors DRD1A and DRD2 was detected by immunoblots and autoradiography, findings compatible with the notion of abnormal vesicle release. Extensive transcriptome studies via microarrays and quantitative real-time RT-PCR validation of altered Homer1, Cb1, Atf2 and Pde7b transcript levels indicated a progressive reduction in the postsynaptic DA response. As functional consequences, long term depression was absent in corticostriatal slices from aged transgenic mice and an insidious decrease of spontaneous locomotor activity of these animals was found in open field tests. Taken together, the dysfunctional neurotransmission and decreased synaptic plasticity seen in the A53T-SNCA overexpressing mice reflects early functional changes within the basal ganglia resulting from synucleinopathy prior to frank neurodegeneration. Thus, preclinical stages of PD may be modeled in this mouse. Tissue was dissected from the brain of 6 months old (2 WT / 2 TgA / 2 TgB striata, 2 WT / 2 TgA / 2 TgB brainstems/midbrains, 2 WT / 2 TgA / 2 TgB cerebella) and of 18+ months old mice (4 WT / 2 TgA / 2 TgB striata, 6 WT / 4 TgA / 3 TgB brainstems/midbrains, 6 WT / 5 TgA / 4 TgB cerebella). Tissues from individual, particularly old mice up to 28 months age were included here to strengthen the definition of progression markers reflecting old age.
2010-05-27 | E-GEOD-20547 | biostudies-arrayexpress
Project description:Genetic variation modulating risk of sporadic Parkinson’s disease (PD) has been primarily explored through genome wide association studies (GWAS). However, like many other common genetic diseases, the impacted genes remain largely unknown. Here, we used single-cell RNA-seq to characterize dopaminergic (DA) neuron populations in the mouse brain at embryonic and early postnatal timepoints. These data facilitated unbiased identification of DA neuron subpopulations through their unique transcriptional profiles, including a novel postnatal neuroblast population and substantia nigra (SN) DA neurons. We use these population-specific data to develop a scoring system to prioritize candidate genes in all 49 GWAS intervals implicated in PD risk, including known PD genes and many with extensive supporting literature. As proof of principle, we confirm that the nigrostriatal pathway is compromised in Cplx1 null mice. Ultimately, this systematic approach establishes biologically pertinent candidates and testable hypotheses for sporadic PD, informing a new era of PD genetic research.
2018-01-31 | GSE108020 | GEO
Project description:Parkinson’s disease (PD), the second most frequent neurodegenerative disorder at old age, can be caused by elevated expression, or the A53T mutation, of the presynaptic protein alpha-synuclein (SNCA). PD is characterized pathologically by the preferential vulnerability of the dopaminergic nigrostriatal projection neurons. Here, we used two mouse lines overexpressing human A53T-SNCA around ages 6 and 18 months and studied striatal dysfunction in the absence of neurodegeneration to understand early disease mechanisms. High pressure liquid chromatography analysis of striatal neurotransmitter content demonstrated that dopamine (DA) levels correlated directly with the level of expression of SNCA, an observation also observed in SNCA deficient mice. In the striatum of aged A53TSNCA overexpressing mice, where DA levels were elevated, a paradoxical upregulation of dopamine receptors DRD1A and DRD2 was detected by immunoblots and autoradiography, findings compatible with the notion of abnormal vesicle release. Extensive transcriptome studies via microarrays and quantitative real-time RT-PCR validation of altered Homer1, Cb1, Atf2 and Pde7b transcript levels indicated a progressive reduction in the postsynaptic DA response. As functional consequences, long term depression was absent in corticostriatal slices from aged transgenic mice and an insidious decrease of spontaneous locomotor activity of these animals was found in open field tests. Taken together, the dysfunctional neurotransmission and decreased synaptic plasticity seen in the A53T-SNCA overexpressing mice reflects early functional changes within the basal ganglia resulting from synucleinopathy prior to frank neurodegeneration. Thus, preclinical stages of PD may be modeled in this mouse. Parkinson’s disease (PD), the second most frequent neurodegenerative disorder at old age, can be caused by elevated expression, or the A53T mutation, of the presynaptic protein alpha-synuclein (SNCA). PD is characterized pathologically by the preferential vulnerability of the dopaminergic nigrostriatal projection neurons. Here, we used two mouse lines overexpressing human A53T-SNCA around ages 6 and 18 months and studied striatal dysfunction in the absence of neurodegeneration to understand early disease mechanisms. High pressure liquid chromatography analysis of striatal neurotransmitter content demonstrated that dopamine (DA) levels correlated directly with the level of expression of SNCA, an observation also observed in SNCA deficient mice. In the striatum of aged A53TSNCA overexpressing mice, where DA levels were elevated, a paradoxical upregulation of dopamine receptors DRD1A and DRD2 was detected by immunoblots and autoradiography, findings compatible with the notion of abnormal vesicle release. Extensive transcriptome studies via microarrays and quantitative real-time RT-PCR validation of altered Homer1, Cb1, Atf2 and Pde7b transcript levels indicated a progressive reduction in the postsynaptic DA response. As functional consequences, long term depression was absent in corticostriatal slices from aged transgenic mice and an insidious decrease of spontaneous locomotor activity of these animals was found in open field tests. Taken together, the dysfunctional neurotransmission and decreased synaptic plasticity seen in the A53T-SNCA overexpressing mice reflects early functional changes within the basal ganglia resulting from synucleinopathy prior to frank neurodegeneration. Thus, preclinical stages of PD may be modeled in this mouse.
2010-05-01 | GSE20547 | GEO
Project description:A major barrier to research on Parkinson’s disease (PD) is inaccessibility of diseased tissue for study. One solution is to derive induced pluripotent stem cells (iPSCs) from patients with PD and differentiate them into neurons affected by disease. We created an iPSC model of PD caused by triplication of SNCA encoding ?-synuclein. ?-Synuclein dysfunction is common to all forms of PD, and SNCA triplication leads to fully penetrant familial PD with accelerated pathogenesis. After differentiation of iPSCs into neurons enriched for midbrain dopaminergic subtypes, those from the patient contain double ?-synuclein protein compared to those from an unaffected relative, precisely recapitulating the cause of PD in these individuals. A measurable biomarker makes this model ideal for drug screening for compounds that reduce levels of ?-synuclein, and for mechanistic experiments to study PD pathogenesis. This SNP microarray study was carried out to confirm presence of SNCA triplication in the affected subject and the derived cell lines. 11 samples were analysed: genomic DNA from the two subjects in the study, the two parent fibroblast lines (AST denoting alpha-synuclein triplication and NAS denoting normal alpha-synuclein), two iPSC lines from each parent fibroblast line (four in total), a human embryonic stem cell line (SHEF4) and two neuronal samples one each from AST and NAS iPSCs).
2011-09-14 | E-GEOD-28366 | biostudies-arrayexpress
Project description:Importance. Biological markers of Parkinson’s disease are essential for achieving disease modification. Objective. To determine the association of SNCA blood transcript levels with prevalence of Parkinson’s disease. Background. The SNCA locus is preferentially transcribed in neurons and blood cells. Non-coding genetic variants and neuronal aggregates of α-synuclein protein associate this locus with sporadic Parkinson’s disease and suggest a potential role for abnormal SNCA transcription in the disease mechanism. Here we investigated variation in intracellular SNCA gene expression and SNCA transcript isoform abundance in circulating blood cells of cases with PD and controls in a network of biobanks that represent regional, national, and international populations. Design, Setting, Participants. Three cross-sectional, case-control studies nested in observational biomarker studies. 222 cases with early-stage clinical PD and 183 controls were enrolled from 2005 to 2010 in the Harvard Biomarker Study (HBS) at two Harvard-affiliated tertiary care centers. 76 cases with dopamine transporter imaging (DAT)-confirmed PD and 42 controls were enrolled between August 2007 and December 2008 in the Blood α-Synuclein, Gene Expression and Smell Testing as Diagnostic and Prognostic Biomarkers in Parkinson’s Disease Study (PROBE) study from 22 US tertiary care centers. 202 DAT-confirmed cases with de novo PD and 138 controls were enrolled in the Parkinson’s Progression Markers Initiative (PPMI) between July 2010 and November 2012 from 22 US and international tertiary care centers. Main Outcome Measures. Association of intracellular SNCA transcript abundance with PD estimated on analog and digital expression platforms. Results. Reduced levels of SNCA transcripts were associated with early-stage clinical PD, neuroimaging-confirmed PD, and untreated, neuroimaging-confirmed PD in accessible, peripheral blood cells from a total of 863 individuals. SNCA expression was reduced by 17%, 22%, and 16% in cases compared to controls in the HBS, PROBE, and PPMI study with P values of 0.004, 0.025, and 0.018, respectively, after adjusting for clinical, hematological, and processing covariates. Specific SNCA transcripts with long 3’ untranslated regions (UTR) and those skipping exon 5 are implicated in the accumulation and mitochondrial targeting of α-synuclein protein in Parkinson’s pathology. These transcript isoforms were linked to PD through digital expression analysis. Individuals in the lowest quartile of SNCA expression values had covariate-adjusted odds ratios for PD of 2.14 (95% C. I. 1.1-4.1), 4.5 (95% C. I. 1.3-15), and 2.1 (1.1-4.0) compared to individuals in the highest quartile of expression values in the HBS, PROBE, and PPMI study, respectively. Conclusions and Relevance. Reduced levels of SNCA expression, particularly of disease-relevant transcripts with extended 3’ UTR or exon 5 skipping, are associated with early-stage PD. These findings support a potential role for SNCA as a transcriptional marker of PD and may have implications for patient stratification and risk assessment.
2015-06-01 | GSE57475 | GEO
Project description:Parkinson disease (PD) is a neurodegenerative disease characterized by the accumulation of alpha-synuclein (SNCA) and other proteins in aggregates termed âLewy Bodiesâ within neurons. PD has both genetic and environmental risk factors, and while processes leading to aberrant protein aggregation are unknown, past work points to abnormal levels of SNCA and other proteins. Although several genome-wide studies have been performed for PD, these have focused on DNA sequence variants by genome-wide association studies (GWAS) and on RNA levels (microarray transcriptomics), while genome-wide proteomics analysis has been lacking. After appropriate filters, proteomics identified 3,558 unique proteins and 283 of these (7.9%) were significantly different between PD and controls (q-value<0.05). RNA-sequencing identified 17,580 protein-coding genes and 1,095 of these (6.2%) were significantly different (FDR p-value<0.05), but only 166 of the FDR significant protein-coding genes (0.94%) were present among the 3,558 proteins characterized. Of these 166, eight genes (4.8%) were significant in both studies, with the same direction of effect. Functional enrichment analysis of the proteomics results strongly supports mitochondrial-related pathways, while comparable analysis of the RNA-sequencing results implicates protein folding pathways and metallothioneins. Ten of the implicated genes or proteins co-localized to GWAS loci. Evidence implicating SNCA was stronger in proteomics than in RNA-sequencing analyses. Notably, differentially expressed protein-coding genes were more likely to not be characterized in the proteomics analysis, which lessens the ability to compare across platforms. Combining multiple genome-wide platforms offers novel insights into the pathological processes responsible for this disease by identifying pathways implicated across methodologies. The study consists of mRNA-Seq (29 PD, 44 neurologically normal controls) and three-stage Mass Spectrometry Tandem Mass Tag Proteomics (12 PD, 12 neurologically normal controls) performed in post-mortem BA9 brain tissue. The proteomics samples are a subset of the RNA-Seq samples.
2016-01-15 | E-GEOD-68719 | biostudies-arrayexpress
Project description:Several mutations that cause Parkinson’s disease (PD) have been identified over the past decade. These account for 15-25% of PD cases; the rest of the cases are considered sporadic. Currently, it is accepted that PD is not a single monolithic disease but rather a constellation of diseases with some common phenotypes. While rodent models exist for some of the PD-causing mutations, research on the sporadic forms of PD is lagging due to a lack of cellular models. In our study, we differentiated PD patient-derived dopaminergic (DA) neurons from the induced pluripotent stem cells (iPSCs) of several PD-causing mutations as well as from sporadic PD patients. Strikingly, we observed a common neurophysiological phenotype: neurons derived from PD patients had a severe reduction in the rate of synaptic currents compared to those derived from healthy controls. While the relationship between mutations in genes such as the SNCA and LRRK2 and a reduction in synaptic transmission has been investigated before, here we show evidence that the pathogenesis of the synapses in neurons is a general phenotype in PD. Analysis of RNA sequencing results displayed changes in gene expression in different synaptic mechanisms as well as other affected pathways such as extracellular matrix-related pathways. Some of these dysregulated pathways are common to all PD patients (monogenic or idiopathic). Our data, therefore, show changes that are central and convergent to PD and suggest a strong involvement of the tetra-partite synapse in PD pathophysiology. RNA sequencing
2023-11-20 | GSE207533 | GEO
Project description:Genome-wide association studies (GWAS) have uncovered thousands of single nucleotide polymorphisms (SNPs) that are associated with Parkinson's disease (PD) risk. The functions of most of these SNPs, including the cell type they influence, and how they affect PD etiology remain largely unknown. To identify functional SNPs, we aligned PD risk SNPs within active regulatory regions of DNA in microglia, a cell type implicated in PD development. Out of 6,749 ‘SNPs of interest’ from the most recent PD GWAS metanalysis, 73 were located in open regulatory chromatin as determined by both ATAC-seq and H3K27ac ChIP-seq. We identified an active enhancer in microglia in intron two of SNCA that overlaps two PD risk SNPs, rs2737004 and rs2619356. In iPSC-derived microglia, CRISPR/Cas9 deletion of the open chromatin encompassing these SNPs caused reduced expression of multiple genes including SNCA and the adjacent gene MMRN1. Loss of the enhancer also led to upregulation of genes involved in glucose metabolism, a process that is known to be altered in PD patients. Our work expands the role of SNCA in Parkinson’s Disease and provides a connection between PD-associated genetic variants and underlying biology that points to a risk mechanism in microglia.
2024-01-21 | GSE245523 | GEO