Distinct Impacts of Alpha-Synuclein Overexpression on the Hippocampal Epigenome of Mice in Standard and Enriched Environments
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE228961 | GEO | 2023/04/08
REPOSITORIES: GEO
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Project description:Alpha synuclein (SNCA) has been linked to neurodegenerative diseases (synucleinopathies) that include Parkinson’s disease (PD). Although the primary neurodegeneration in PD involves nigrostriatal dopaminergic neurons, more extensive yet regionally selective neurodegeneration is observed in other synucleinopathies. Furthermore, SNCA is ubiquitously expressed in neurons and numerous neuronal systems are dysfunctional in PD. Therefore it is of interest to understand how overexpression of SNCA affects neuronal function in regions not directly targeted for neurodegeneration in PD. To gain a better understanding of the consequences of excessive SNCA expression on basal ganglia function, we performed transcriptome analysis of striatal tissue from male Thy1-aSyn-mice and wt littermates. The present study investigated the consequences of SNCA overexpression on cellular processes and functions in the striatum of mice overexpressing wild-type, human SNCA under the Thy1 promoter (Thy1-aSyn mice) by transcriptome analysis. The analysis revealed alterations in multiple biological processes in the striatum of Thy1-aSyn mice, including synaptic plasticity, signaling, transcription, apoptosis, and neurogenesis. The present study investigated the consequences of SNCA overexpression on cellular processes and functions in the striatum of mice overexpressing wild-type, human SNCA under the Thy1 promoter (Thy1-aSyn mice) by transcriptome analysis. The analysis revealed alterations in multiple biological processes in the striatum of Thy1-aSyn mice, including synaptic plasticity, signaling, transcription, apoptosis, and neurogenesis.
2012-02-11 | GSE35723 | GEO
Project description:A growing body of evidence suggests that nuclear alpha-synuclein (aSyn) plays a role in the pathogenesis of Parkinson’s disease (PD). However, this question has been difficult to address as controlling the localization of aSyn in experimental systems often requires protein overexpression, which affects its aggregation propensity. To overcome this, we engineered Snca-NLS mice which localize endogenous aSyn to the nucleus. We characterized these mice on a behavioral, histological, and biochemical level to determine whether the increase of nuclear aSyn is sufficient to elicit PD-like phenotypes. SncaNLS mice exhibit age-dependent motor deficits and altered gastrointestinal function. We found that these phenotypes were not linked to aSyn aggregation or phosphorylation. Through histological analyses, we observed motor cortex atrophy in the absence of midbrain dopaminergic neurodegeneration. We sampled cortical proteomes of Snca-NLS mice and controls to determine the molecular underpinnings of these pathologies. Interestingly, we found several dysregulated proteins involved in dopaminergic signalling, including Darpp32, Pde10a, and Gng7, which we further confirmed was decreased in cortical samples of the Snca-NLS mice compared to controls. These results suggest that chronic endogenous nuclear aSyn can elicit toxic phenotypes in mice, independent of its aggregation. This model raises key questions related to the mechanism of aSyn toxicity in PD and provides a new model to study an underappreciated aspect of PD pathogenesis.
2022-04-06 | PXD032065 | Pride
Project description:Using a mouse model overexpressing human SNCA and profiling the hippocampal transcriptome, we assessed gene-environment interactions to reveal perturbations in gene expression and their modulation through long-term enriched environment (EE) exposure. We observed that EE prevented perturbations of genes attributed to neuronal and glial cell types and linked to glutamate signaling, calcium homeostasis, inflammation, and related processes of SNCA biology. Cluster and promoter analyses suggested driver genes that specifically responded to the EE, and pointed to a pivotal role of Egr1 to have hierarchically activated other drivers. We suggest a model in which EE-induced driver genes prevent and counter-balance perturbations of SNCA overexpression, restoring a largely normalized gene expression profile and system state.
2018-05-14 | GSE96961 | GEO
Project description:Alpha synuclein (SNCA) has been linked to neurodegenerative diseases (synucleinopathies) that include Parkinson’s disease (PD). Although the primary neurodegeneration in PD involves nigrostriatal dopaminergic neurons, more extensive yet regionally selective neurodegeneration is observed in other synucleinopathies. Furthermore, SNCA is ubiquitously expressed in neurons and numerous neuronal systems are dysfunctional in PD. Therefore it is of interest to understand how overexpression of SNCA affects neuronal function in regions not directly targeted for neurodegeneration in PD. To gain a better understanding of the consequences of excessive SNCA expression on basal ganglia function, we performed transcriptome analysis of striatal tissue from male Thy1-aSyn-mice and wt littermates. The present study investigated the consequences of SNCA overexpression on cellular processes and functions in the striatum of mice overexpressing wild-type, human SNCA under the Thy1 promoter (Thy1-aSyn mice) by transcriptome analysis. The analysis revealed alterations in multiple biological processes in the striatum of Thy1-aSyn mice, including synaptic plasticity, signaling, transcription, apoptosis, and neurogenesis. The present study investigated the consequences of SNCA overexpression on cellular processes and functions in the striatum of mice overexpressing wild-type, human SNCA under the Thy1 promoter (Thy1-aSyn mice) by transcriptome analysis. The analysis revealed alterations in multiple biological processes in the striatum of Thy1-aSyn mice, including synaptic plasticity, signaling, transcription, apoptosis, and neurogenesis. Animal care was conducted in accordance with the U. S. Public Health Service Guide for the Care and Use of Laboratory Animals and procedures were approved by the University of California, Los Angeles (UCLA), I.A.C.U. Committee. Transgenic (tg) mice overexpressing human wt SNCA under the Thy-1 promoter (Thy1-aSyn) created previously in a mixed C57BL/6-DBA background were kept in this background by breeding mutant females with wt males. Only male mice were used in the study. The genotype of all tg and wt mice was verified by PCR analysis of tail DNA. Animals were maintained on a 12 hr light/dark cycle with free access to water and food. Six-month old male Thy1-aSyn and wt littermates were sacrificed by decapitation. For microarray analysis, whole striata from each hemisphere were immediately dissected and pooled for each brain. Tissue was permeated in RNAlater (Qiagen, Valencia, CA), frozen in liquid nitrogen, and stored at - 80º C until used for RNA preparation. For PCR verification of transcriptional changes and for protein extracts preparation, brains from 5 male Thy1-aSyn and 5 wt littermates were obtained as above but then the brains were placed in a metal brain mold with grooves to ensure reproducible cutting of thick brain slices. A first coronal cut was made with a razor blade to remove the frontal part of the brain (at bregma + 1mm, at the anterior level of striatum). The following 1mm coronal slice (including the striatum but no globus pallidus) was used to dissect out striatal tissue. A horizontal cut was made through the anterior commissures to exclude the nucleus accumbens. One cube of striatum was dissected out from each hemisphere, taking care not to include any corpus callosum, choroid plexus, or subventricular zone. Samples were stored at -80º C until further processing. Total RNA was extracted from striata of Thy1-aSyn and wt littermates (all males) with Trizol (Invitrogen, Carlsbad, CA), followed by a clean-up step with RNeasy columns (Qiagen) and RNA integrity check using a Bioanalyzer (Agilent Tech., Foster city, CA). RNA samples were pooled, one pool representing the six control wt mice and the other representing the six SNCA overexpressing animals. After synthesis, using Superscript (Invitrogen) and labeling using the ENZO labeling kit (Affymetrix Inc., Santa Clara, CA), cRNA probes were hybridized to mouse MOE-430A GeneChip arrays (Affymetrix) following the manufacturer’s protocol at the UCLA microarray core facility. Significant differential gene expression between pooled tg and wt samples was ascertained by estimation of signal log2 ratios (or fold changes in expression values), after quality control checks, data normalization and estimating expression values using the Affymetrix Microarray Suite 5.0 Software (MAS 5.0). After pairwise comparisons and filtering of this gene list using the following criteria: change p-value <0.005 for induce genes, change p-value > 0.995 for decreased genes, signal log2 ratio > 0.6 (> 1.52 fold change), excluding probes called absent in both groups, a list of differentially expressed genes was generated. We used various statistical softwares and databases to ascertain pathways affected by overexpression of SNCA that are associated with overrepresented genes in this gene list, including, the functional annotation tools accessible through DAVID (Database for Annotation, Visualization and Integrated Discovery, http://david.abcc.ncifcrf.gov )
2012-02-11 | E-GEOD-35723 | biostudies-arrayexpress
Project description:We used a transgenic mouse model overexpressing the complete human SNCA genes modeling familial and sporadic forms of Parkinson’s disease to study whether environmental conditions such as standard versus enriched environment changes the gut microbiome and influences disease progression.
2019-10-01 | GSE137213 | GEO
Project description:Alpha-synuclein (aSyn) is widely portrayed as the main culprit on Parkinson’s Disease (PD) pathophysiology. However, the precise molecular function of the protein remains elusive. Recent evidence suggests that aSyn may play a role on transcription regulation, possibly by modulating the acetylation status of histones. Our study aimed to evaluate the impact of wild-type (WT) and mutant A30P aSyn on gene expression, in a dopaminergic neuronal cell model, and decipher potential mechanisms behind aSyn-induced transcriptional deregulation. We performed RNA-sequencing in Lund Human Mesencephalic (LUHMES) cells expressing endogenous (control) or increased WT or A30P aSyn levels. Compared to control, LUHMES cells expressing aSyn exhibited robust changes in the expression of several genes, including downregulation of major genes involved in DNA repair. Expressing WT aSyn, unlike A30P aSyn, led to increased DNA damage and phosphorylated p53 levels. In our dopaminergic neuronal cell model, aSyn expression promoted lower histone 3 acetylation levels. Excitingly, treatment with sodium butyrate, a histone deacetylase inhibitor (HDACi), was able to rescue WT aSyn-induced DNA damage, possibly via upregulation of genes involved in DNA repair. Overall, our findings provide compelling, pioneer evidence for a novel mechanism associated with aSyn neurotoxicity in dopaminergic cells, which could be ameliorated with a HDACi. Prospective studies will be crucial to further validate these findings and its relevance to our knowledge of PD.
2017-03-31 | GSE89115 | 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:Several genetic and environmental risk factors for Parkinson’s disease have been identified that converge on mitochondria as central elements in the disease process. However, the mechanisms by which mitochondrial dysfunction contributes to neurodegeneration remain incompletely understood. Non-bioenergetic pathways of the mitochondria are increasingly appreciated, but confounding bioenergetic defects are a major barrier to experimental validation. Here, we describe a novel bioenergetics-independent mechanism by which mild mitochondrial protein import stress augments neurodegeneration. We induced this mitochondrial protein import stress in an established mouse model of Parkinson’s disease expressing the A53T mutated form of human alpha-synuclein (SNCA). Mice with import stress in addition to the A53T mutation demonstrated increased size of SNCA aggregates, co-aggregation of mitochondrial preproteins with SNCA protein, worsened neurodegeneration and changes in gene expression, as determined by whole-transcriptome RNA-sequencing analysis of the forebrain (striatum), cerebellum, spinal cord, as well as heart and skeletal muscle.
2023-10-08 | GSE236975 | 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 α-synuclein. α-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 α-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 α-synuclein, and for mechanistic experiments to study PD pathogenesis. This gene expression microarray study was carried out as part of the validation process for demonstrating that the generated iPSC lines are pluripotent. 5 samples were analysed: two clonal iPSC lines from each of two genotypes (four in total; AST denoting alpha-synuclein triplication and NAS denoting normal alpha-synuclein), a human embryonic stem cell line (SHEF4). All cultured in self-renewal conditions, mTeSR1
2011-09-14 | E-GEOD-30792 | 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