Transcriptional phenotype in a novel ataxin-3 knock-in mouse model for spinocerebellar ataxia type 3
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PROVIDER: PRJNA607747 | ENA |
REPOSITORIES: ENA
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Project description:Spinocerebellar ataxia type 3 is the most common autosomal dominant inherited ataxia worldwide and caused by a CAG repeat expansion in the Ataxin-3 gene resulting in a polyQ expansion in the corresponding protein. The disease is characterized by neuropathological (aggregate formation, cell loss), phenotypical (gait instability, body weight reduction) and transcriptional changes. So far there is no mouse model available representing all the different aspects of the disease, but a representative model is highly needed to gain a better understanding of the disease pathomechanism. Here we characterized a novel Ataxin-3 knock-in mouse model, expressing an expansion of 304 CAG/CAAs either heterozygous or homozygous in the murine Ataxin-3 locus using biochemical, behavioral and transcriptomic approaches. Further, we correlated the transcriptional changes of the knock-in mice to those found in human SCA3 patients, to prove the comparability of our model. The novel Ataxin-3 knock-in mouse is characterized by the expression of polyQ-expanded Ataxin-3 in the murine protein, leading to massive aggregate formation, especially in brain regions known to be vulnerable in SCA3 patients, and impairment of Purkinje cells. Caused by these neuropathological changes, the mice demonstrated phenotypically reduction in body weight accompanied by gait and balance instability. Transcriptomic analysis of cerebellar tissue revealed downregulation of differentially expressed genes enriched in myelinating oligodendrocytes. Comparing these transcriptional changes with those found in cerebellar tissue of SCA3 patients, we discovered an overlap of differentially expressed genes pointing towards disturbances in the myelin sheaths and myelinating oligodendrocytes.
2022-04-01 | GSE145613 | GEO
Project description:Ataxin 1 (Atxn1) is a protein of unknown function associated with cerebellar neurodegeneration in spinocerebellar ataxia type 1 (SCA1). SCA1 is caused by an expanded polyglutamine within Atxn1 by gain-of-function mechanisms. Lack of Atxn1 in mice triggers motor deficits in the absence of neurodegeneration or apparent neuropathological abnormalities.We extracted RNA from cerebellum of 5 Atxn1-null mice and 5 WT. Cerebellar gene expression profiles at 15 weeks of age were generated usSCA1 ing Affymetrix MOE430A arrays. Identifying the molecular pathways regulated by Atxn1 can provide insights into the early molecular mechanisms underlying neuronal dysfunction.
2006-12-01 | E-MEXP-886 | biostudies-arrayexpress
Project description:Transcriptome analysis of extracted total RNA from the the cerebellum and muscle of Spinocerebellar Ataxia 17 knock-in mouse model
2015-08-19 | GSE72176 | GEO
Project description:RNA-Sequencing from human post-mortem Spinocerebellar ataxia type 3 patients. This sequencing experiment was carried out to validate that the transcriptional changes of an Ataxin-3 knock-in mouse model (expressing an expansion of 304 CAG/CAAs either heterozygous or homozygous in the murine Ataxin-3 locus) represent that transcriptional changes seen in the human disease.
| EGAS00001004241 | EGA
Project description:Spinocerebellar ataxia type-1 is caused by an abnormally expanded polyglutamine (polyQ) tract in ataxin-1 protein. These expansions are responsible for protein misfolding and self-assembly into intranuclear inclusion bodies (IIBs) that are linked to neuronal death. Here, we describe a nuclear protein aggregation model of pathogenic human ataxin-1. Using an inducible Sleeping Beauty transposon system, we overexpressed ATXN1Q82 gene in human mesenchymal stem cells that are resistant to the early cytotoxic effects of the mutant protein. We characterized the structure and the protein composition of insoluble polyQ IIBs which gradually occupy the nuclei. In response to their formation, our transcriptome analysis reveals a cerebellum-specific perturbed protein interaction network, primarily affecting protein translation. Our study resolves the previously unknown architecture of insoluble polyQ IIBs and suggests that they affect the assembly and the function of the ribosome. Our inducible cell system faithfully models a human cerebellum at the end-stage of the disease.
2020-02-18 | PXD012709 | Pride
Project description:Spinocerebellar ataxia type 1 (SCA1) is caused by a polyglutamine expansion in the ATXN1 gene leading to an expanded polyglutamine tract in the ATAXIN-1 protein. Ataxin-1 is broadly expressed throughout the brain and is known to be involved in regulating gene expression; however, it is not yet determined if mutant ataxin-1 regulates alternative splicing events. Utilizing SCA1 mouse models, we performed bulk RNA sequencing and looked for misregulated alternative splicing (mAS) events in SCA1 mouse cerebella. We found that mutant ataxin-1 causes mAS events to occur in the SCA1 mouse cerebella. Furthermore, we showed that abnormal splicing events predominantly occur in cell types that express mutant ataxin-1. Less than 25% of the mAS events were also differentially expressed genes (DEGs) and therefore their transcriptional dysregulation was previously unknown in the context of SCA1. We show through gene ontology analysis that mAS events reveal new biological pathways: mAS events showed changes in structural morphogenesis whereas DEGs showed changes in ion channel and transmembrane transport. We also report that mutant ataxin-1 causes dysregulation of expression of other ataxia-causing genes, providing evidence for molecular basis of clinical similarity among otherwise heterogeneous inherited cerebellar ataxias. We also identified the potential mechanism by which mutant ATXN1 causes mAS through its interaction with RBFOX1.
2023-10-20 | GSE232368 | GEO
Project description:The neurodegenerative disease spinocerebellar ataxia type 1 (SCA1) is known to lead to progressive degeneration of specific neuronal populations, including cerebellar Purkinje cells (PCs), brainstem cranial nerve nuclei and inferior olive nuclei, and spinocerebellar tracts. The disease-causing protein ataxin-1 is fairly ubiquitously expressed throughout the brain and spinal cord, but most studies have primarily focused on the role of ataxin-1 in the cerebellum and brainstem. Therefore, the functions of ataxin-1 and the effects of SCA1 mutations in other brain regions including the cortex are not well known. Here, we characterized pathology in the motor cortex of a SCA1 mouse model and performed RNA sequencing in this brain region to investigate the impact of mutant ataxin-1 towards transcriptomic alterations. We identified progressive cortical pathology and significant transcriptomic changes in the motor cortex of a SCA1 mouse model. We also identified progressive, region-specific, colocalization of p62 with mutant ataxin-1 aggregates in broad brain regions, but not the cerebellum or brainstem. A cross-regional comparison of the SCA1 cortical and cerebellar transcriptomic changes identified both common and unique gene expression changes between the two regions, including shared synaptic dysfunction and region-specific kinase regulation. These findings suggest that the cortex is progressively impacted via both shared and region-specific mechanisms in SCA1.
2022-08-22 | GSE211678 | GEO
Project description:Gene-based therapeutic strategies to lower ataxin-2 levels are emerging for neurodegenerative diseases amyotrophic lateral sclerosis (ALS) and spinocerebellar ataxia type 2 (SCA2). To identify additional ways of reducing ataxin-2 levels, we performed a genome-wide screen in human cells for regulators of ataxin-2 and identified RTN4R, the gene encoding the RTN4/NoGo-Receptor, as a top hit. This dataset contains the RNA-sequencing data used to support the conclusions from this study.
2022-10-18 | GSE200530 | GEO
Project description:A number of human neurodegenerative diseases result from the expansion of a glutamine repeat within the disease-causing protein. Spinocerebellar ataxia type1 is one such disease, caused by expansion of a polyglutamine tract in the novel protein ataxin-1. To faithfully model SCA1 in the mouse, we generated knock-in mice carrying 154 CAG repeats in the mouse Sca1 locus. These mice reproduced many aspects of the human disease. Despite ubiquitous expression of the mutant protein, they developed slowly progressive selective neurodegeneration , which is most distinct in Purkinje cells and spinal cord. Alterations in gene expression have been proposed to be involved in the pathogenesis of polyglutamine disease including SCA1, but the changes of gene expression in an authentic disease model have not been characterized. We believe that knowledge of these genes will give insight into the pathophysiology of SCA1 and may ultimately be relevant to the treatment of SCA1.,We will determine gene expression patterns in the cerebellum and forebrain at three different time points.,We propose that the genes whose expression is affected by mutant ataxin-1 expression are effectors for neuronal dysfunction and neuronal degeneration in the knock-in mice. We also hypothesize the difference in the expression levels of these genes accounts for selective vulnerability of neurons.,We will examine three time points: 4 weeks, 11 weeks, and 20 weeks of age. We have shown that the mice developed motor incoordination as revealed by rotating rod test as early as 5 weeks of age but it was not until 10 weeks that they start showing clear neurological phenotype such as clasping. At each point, we will compare the pattern between the mutant and wild-type littermate. Animals will be prepared and sacrificed by a standard procedure. Cerebellum and spinal cord are the most affected areas whereas forebrain shows less neurodegeneration. Tissue will be rapidly dissected from cerebellum and forebrain, frozen in liquid nitrogen, and stored at ?80 C until analysis. Tissues will be sent to the centers (as opposed to RNA). We will be providing 9 tissue samples from three litters for each time point to mitigate any expression differences resulting from subtle differences of procedure or environment where the mice grow.
2007-07-07 | E-GEOD-2867 | biostudies-arrayexpress
Project description:Comparative analysis of cerebellar gene expression changes occurring in Sca1154Q/2Q and Sca7266Q/5Q knock-in mice; Polyglutamine diseases are inherited neurodegenerative disorders caused by expansion of CAG repeats encoding a glutamine tract in the disease-causing proteins. There are nine disorders each having distinct features but also clinical and pathological similarities. In particular, spinocerebellar ataxia type 1 and type 7 (SCA1 and SCA7) patients manifest cerebellar ataxia with degeneration of Purkinje cells. To determine whether the disorders share molecular pathogenic events, we studied two mouse models of SCA1 and SCA7 that express the glutamine-expanded protein from the respective endogenous loci. We found common transcriptional changes, with down-regulation of Insulin-like growth factor binding protein 5 (Igfbp5) representing one of the most robust changes. Igfbp5 down-regulation occurred in granule neurons through a non-cell autonomous mechanism and was concomitant with activation of of the Insulin-like growth factor (IGF) pathway and the type I IGF receptor on Purkinje cells. These data define one common pathogenic response in SCA1 and SCA7 and reveal the importance of intercellular mechanisms in their pathogenesis. Given that SCA1 and SCA7 share a cerebellar degenerative phenotype, we proposed that some shared molecular changes might occur in both diseases, and that common molecular alterations could pinpoint pathways that could be targeted to modulate or monitor the pathogenesis of more than one disease. We focused on transcriptional changes because both ATXN1 and ATXN7 play roles in transcriptional regulation and transcriptional defects can be detected in early-symptomatic stages of both SCA1 and SCA7 mouse models. To test our hypothesis, we examined cerebellar gene expression patterns in SCA1 and SCA7 knock-in (KI) models--Sca1154Q/2Q and Sca7266Q/5Q mice. Experiment Overall Design: Total cerebellar RNA samples were collected from Sca1154Q/2Q knock-in and wild type mice at the early symptomatic disease stage (4 weeks, n=3 knock-in and 3 wild type; 9-12 weeks, n=3 knock-in and 3 wild type). In parallel experiments, total cerebellar RNA samples were collected from Sca7266Q/5Q knock-in and wild type mice also at the early symptomatic disease stage (5 weeks, n=5 knock-in and 5 wild type).
2009-01-09 | E-GEOD-9914 | biostudies-arrayexpress