Brain region-specific and systemic transcriptomic dysregulation in a human alpha-synuclein overexpressing rat model
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ABSTRACT:
ORGANISM(S): Rattus norvegicus
PROVIDER: GSE281984 | GEO | 2025/04/01
REPOSITORIES: GEO
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Project description:GBA mutations are major risk factors for Parkinson’s disease (PD) and Dementia with Lewy Bodies (DLB), two common α-synucleinopathies associated with cognitive impairment. Here, we investigated the role of GBA mutations in cognitive decline by utilizing Gba L444P mutant mice, SNCA transgenic (tg), and Gba-SNCA double mutant mice. Notably, Gba mutant mice showed early cognitive deficits but no PD-like motor deficits up to 12 months old. Conversely, SNCA tg mice displayed age-related motor deficits but no cognitive abnormalities. Gba-SNCA mice exhibited exacerbated motor deficits and cognitive decline. Immunohistological analysis revealed cortical phospho-α-synuclein pathology in SNCA tg mice, which was exacerbated in Gba-SNCA mice, especially in layer 5 cortical neurons. Significantly, Gba mutant mice did not show α-synuclein pathology. Single-nucleus RNA sequencing of cortices instead uncovered selective synaptic vesicle cycle defects in excitatory neurons of Gba mutant and Gba-SNCA mice, via robust downregulation in gene networks regulating synapse vesicle cycle and synapse assembly. Meanwhile SNCA tg mice displayed broader synaptic changes. Immunohistochemical and electron microscopic analyses validated these findings. Together, our results indicate that Gba mutations, while exacerbating pre-existing α-synuclein aggregation and PD-like motor deficits, contribute to cognitive deficits through α-synuclein-independent mechanisms, likely involving dysfunction in synaptic vesicle endocytosis. Additionally, Gba-SNCA mice are a valuable model for studying cognitive and motor deficits in PD and DLB
2025-04-15 | GSE283187 | 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.
2012-02-11 | GSE35723 | GEO
Project description:As the second most frequent neurodegenerative disorder of old age, ParkinsonM-bM-^@M-^Ys disease (PD) can result from autosomal dominant causes like increased alpha-synuclein (SNCA) dosage, or from autosomal recessive causes like PINK1 loss-of-function. Interactions between these triggers and their potential convergence onto shared pathways are crucial to understand, but currently conflicting evidence exists. Here, we crossed previously characterized mice with A53T-SNCA overexpression and mice with PINK1 deletion to generate double mutants (DM). We studied their lifespan and behavior, together with histological and molecular anomalies at late and early ages, respectively. DM animals showed potentiated phenotypes in comparison to both single mutants (SM), with markedly reduced survival after age 450 days and strongly reduced spontaneous movements from age 3 months onwards. A considerable part of DM animals manifested progressive paralysis at ages >1 year and also exhibited protein aggregates with immunoreactivity for pSer129-SNCA, p62, and ubiquitin in spinal cord and basal brain, contrasting with absence of such features from SM. A brain proteome quantification of ubiquitination sites documented altered degradation of SNCA and the DNA-damage marker H2AX at age 18 months. Global brain transcriptome profiles and qPCR validation experiments identified many consistent transcriptional dysregulations already at age 6 weeks, which were absent from SM. The observed downregulations for Dapk1, Dcaf17, Rab42 and upregulations for Dctn5, Mrpl9, Tmem181a, Xaf1 reflect changes in ubiquitination, mitochondrial / synaptic / microtubular dynamics, and DNA damage. Thus, our study confirmed that SNCA-triggered neurotoxicity is exacerbated by the absence of PINK1, and identified a novel molecular signature that is detectable early in the course of this double pathology. Factorial design comparing Pink1 knock-out/A53T-SNCA double transgenic mice with appropriate wild-type controls (129SvEv+FVB/N) in three different tissues (cerebellum, midbrain, striatum)
2014-11-04 | E-GEOD-60414 | biostudies-arrayexpress
Project description:SNCA, the first gene associated with Parkinson’s disease, encodes the α-synuclein protein, the predominant component within pathological inclusions termed Lewy bodies. We use 3D midbrain organoids, differentiated from human induced pluripotent stem cells derived from patients carrying a triplication of the SNCA gene and from CRISPR/Cas9 corrected isogenic control iPSCs. These human midbrain organoids recapitulate key features of α-synuclein pathology observed in the brains of patients with synucleinopathies. We used single cell RNA sequencing to characterize the cell types within these organoids. We find an equal proportion of neuronal and glial cells. The neuronal populations consist of dopmainergic, excitatory and inhibitory neurons in early and late stages of maturation as well as neural precursor cells. The glial populations consist of dividing radial glia, radial glia, astrocytes and early oligodendorcytes.
2021-11-02 | GSE186780 | GEO
Project description:Elevated alpha-synuclein (SNCA) gene expression is associated with transcriptional deregulation and increased risk of Parkinson’s disease, which may be partially ameliorated by environmental enrichment. At the molecular level, emerging evidence indicates that excess alpha-synuclein protein (aSyn) impacts the epigenome through direct and/or indirect mechanisms. However, the extents to which both aSyn and the environment converge at the epigenome and whether epigenetic alterations underpin the preventive effects of environmental factors on transcription remain to be elucidated. Here, we profiled five DNA and histone modifications in the hippocampus of wild-type and transgenic mice overexpressing human SNCA. Mice of each genotype were housed under either standard conditions or in an enriched environment (EE) for 12 months. SNCA overexpression induced similar hippocampal DNA hydroxymethylation and H3K27 acetylation changes in both environments, and was associated with environment-dependent changes to H3K4 methylation. These H3K4 methylation changes included loci where the EE ameliorated the impacts of the transgene as well as loci resistant to the effects of environmental enrichment in transgenic mice. In addition, select H3K4 monomethylation alterations were associated with changes in mRNA expression. Our results suggested an environment-dependent impact of excess aSyn on some functionally relevant parts of the epigenome, and will ultimately enhance our understanding of the molecular etiology of Parkinson’s disease and other synucleinopathies.
2023-04-08 | GSE228961 | GEO
Project description:As the second most frequent neurodegenerative disorder of old age, Parkinson’s disease (PD) can result from autosomal dominant causes like increased alpha-synuclein (SNCA) dosage, or from autosomal recessive causes like PINK1 loss-of-function. Interactions between these triggers and their potential convergence onto shared pathways are crucial to understand, but currently conflicting evidence exists. Here, we crossed previously characterized mice with A53T-SNCA overexpression and mice with PINK1 deletion to generate double mutants (DM). We studied their lifespan and behavior, together with histological and molecular anomalies at late and early ages, respectively. DM animals showed potentiated phenotypes in comparison to both single mutants (SM), with markedly reduced survival after age 450 days and strongly reduced spontaneous movements from age 3 months onwards. A considerable part of DM animals manifested progressive paralysis at ages >1 year and also exhibited protein aggregates with immunoreactivity for pSer129-SNCA, p62, and ubiquitin in spinal cord and basal brain, contrasting with absence of such features from SM. A brain proteome quantification of ubiquitination sites documented altered degradation of SNCA and the DNA-damage marker H2AX at age 18 months. Global brain transcriptome profiles and qPCR validation experiments identified many consistent transcriptional dysregulations already at age 6 weeks, which were absent from SM. The observed downregulations for Dapk1, Dcaf17, Rab42 and upregulations for Dctn5, Mrpl9, Tmem181a, Xaf1 reflect changes in ubiquitination, mitochondrial / synaptic / microtubular dynamics, and DNA damage. Thus, our study confirmed that SNCA-triggered neurotoxicity is exacerbated by the absence of PINK1, and identified a novel molecular signature that is detectable early in the course of this double pathology.
2014-11-04 | GSE60414 | GEO
Project description:Alpha-synuclein is an abundant protein implicated in synaptic function and plasticity, but the molecular mechanism of its action is not understood. Missense mutations and gene duplication/triplication events result in Parkinson's disease, a neurodegenerative disorder of old age with impaired movement and emotion control. Here, we systematically investigated the striatal as well as the cerebellar transcriptome profile of alpha-synuclein-deficient mice via a genome-wide microarray survey in order to gain hypothesis-free molecular insights into the physiological function of alpha-synuclein. A genotype-dependent, specific and strong downregulation of forkhead box P1 (Foxp1) transcript levels was observed in all brain regions from postnatal age until old age and could be validated by qPCR. In view of the co-localization and heterodimer formation of FOXP1 with FOXP2, a transcription factor with a well established role for vocalization, and the reported regulation of both alpha-synuclein and FOXP2 expression during avian song learning, we performed a detailed assessment of mouse movements and vocalizations in the postnatal period. While there was no difference in isolation-induced behavioral activity in these animals, the alpha-synuclein-deficient mice exhibited an increased production of isolation-induced ultrasonic vocalizations (USVs). This phenotype might also reflect the reduced expression of the anxiety-related GABA-A receptor subunit gamma 2 (Gabrg2) we observed. Taken together, we identified an early behavioral consequence of alpha-synuclein deficiency and accompanying molecular changes, which supports the notion that the neural connectivity of sound or emotion control systems is affected. Factorial design comparing SNCA knock-out mice with wild type littermates in two different tissues (striatum, cerebellum) at two different timepoints (6 and 21 month)
2010-07-21 | E-GEOD-19534 | biostudies-arrayexpress
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:The pre-synaptic protein α-synuclein is a key player in the pathogenesis of Parkinson's disease. Together with accumulation and missfolding of α-synuclein protofibrils serve as seed structures for the aggregation of numerous proteins in the cytoplasm of neuronal cells, the so-called Lewy bodies. Furthermore, missense mutations in the SNCA gene and gene multiplications lead to autosomal dominant forms of familiar PD. However, so far the exact biological role of α-synuclein in normal brain is elusive. To gain more insights into the biological function of this protein we monitored whole genome expression changes in dopaminergic neuroblastoma cells (SH-SY5Y) caused by a 90% reduction of α-synuclein by RNA interference. Keywords: whole genome expression changes through the loss of α-synuclein
2009-02-01 | GSE9807 | 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