Whole exome sequencing in patients with ALS and concomitant FTD lacking the C9orf72 repeat expansion
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ABSTRACT:
PROVIDER: EGAS00001002439 | EGA |
REPOSITORIES: EGA
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Project description:The study design involves the proteomics characterization of primary skin fibroblast cell lines derived from skin biopsies from patients affected by either amyotrophic lateral sclerosis (ALS) or frontotemporal dementia (FTD). Patients enrolled were divided in three groups: 1) ALS patients carrying the C9ORF72 repeat expansion as main genetic mutation (c9orf72 pos; n=6), 2) sporadic ALS patients, carrying mutations other than the C9ORF72 repeat expansion (c9orf72 neg; n=8), 3) FTD patients carrying the C9ORF72 repeat expansion (FTD; n=2). Total protein extracts were obtained from primary skin fibroblasts cultures and trypsin digested. Shotgun proteomics by LC-MS/MS (two technical replicates per sample) and systems biology analyses were performed as follows
2021-11-02 | PXD023866 | Pride
Project description:G4C2 repeat expansions within the C9orf72 gene are the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The repeats undergo repeat-associated non-ATG translation to generate toxic dipeptide repeat proteins. Here, we show that insulin/Igf signalling is reduced in fly models of C9orf72 repeat expansion using RNA-sequencing of adult brain. We further demonstrate that activation of insulin/Igf signalling can mitigate multiple neurodegenerative phenotypes in flies expressing either expanded G4C2 repeats or the toxic dipeptide repeat protein poly-GR. Levels of poly-GR are reduced when components of the insulin/Igf signalling pathway are genetically activated in the diseased flies, suggesting a mechanism of rescue. Modulating insulin signalling in mammalian cells also lowers poly-GR levels. Remarkably, systemic injection of insulin improves the survival of flies expressing G4C2 repeats. Overall, our data suggest that modulation of insulin/Igf signalling could be an effective therapeutic approach against C9orf72 ALS/FTD.
2021-03-20 | GSE151826 | GEO
Project description:In this study we investigated the role of SRSF1 in mitigating locomotor defect in C9ORF72-ALS/FTD Drosophila lines. We analysed the transcriptomes of Drosophila heads from the same lines: (i) control flies expressing 3 G4C2 repeats and a luciferase-RNAi control (G4C2x3 + C-RNAi); (ii) C9ORF72-ALS/FTD model expressing 36 G4C2 repeats and the RNAi control (G4C2x36 + C-RNAi); (iii) C9ORF72-ALS/FTD-neuroprotected flies expressing 36 G4C2 repeats and the disrupted SRSF1 allele (G4C2x36 + ΔSRSF1). RNA samples were profiled using Drosophila 3' IVT gene expression Affymetrix microarrays prior to qRT-PCR validation of the SRSF1 depletion in neuroprotected flies. This study is part of a larger study that investigates the mitigating role of SRSF1 at whole-genome level to detect transcriptomal alterations and neuronal hyperexcitability in C9ORF72-linked amyotrophic lateral sclerosis.
2021-07-21 | GSE138592 | GEO
Project description:Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are part of a clinical, pathological and genetic continuum. The purpose of the present study was to assess the mutation burden that is present in ALS and/or FTD known disease-causing genes in 54 patients (16 with available postmortem neuropathological diagnosis) with concurrent ALS and FTD (ALS/FTD) not-carrying the C9orf72 hexanucleotide repeat expansion, the most important genetic cause in both diseases.
| EGAD00001003409 | EGA
Project description:N6-methyladenosine (m6A) is the most prevalent internal mRNA modification and regulates RNA metabolism. Repeat expansion in C9ORF72 is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal degeneration (FTD). Here, we showed that m6A is downregulated in C9ORF72-ALS/FTD patient-derived iPSC-differentiated neurons and postmortem brain tissues. The global m6A hypomethylation leads to transcriptome-wide mRNA stabilization and upregulated gene expression, especially ones involved in synaptic activity and neuronal functions. The m6A modification in the C9ORF72 intron sequence preceding the expanded repeats enhances RNA degradation via the nuclear reader YTHDC1. The m6A reduction leads to increased accumulation of repeat RNA and poly-dipeptides. Moreover, the antisense RNA can also be regulated by m6A. Elevating m6A level significantly reduces both sense and antisense repeat RNA and poly-dipeptides, rescues global mRNA homeostasis, and improves survival of C9ORF72-ALS/FTD patient neurons.
2023-06-09 | GSE203579 | GEO
Project description:N6-methyladenosine (m6A) is the most prevalent internal mRNA modification and regulates RNA metabolism. Repeat expansion in C9ORF72 is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal degeneration (FTD). Here, we showed that m6A is downregulated in C9ORF72-ALS/FTD patient-derived iPSC-differentiated neurons and postmortem brain tissues. The global m6A hypomethylation leads to transcriptome-wide mRNA stabilization and upregulated gene expression, especially ones involved in synaptic activity and neuronal functions. The m6A modification in the C9ORF72 intron sequence preceding the expanded repeats enhances RNA degradation via the nuclear reader YTHDC1. The m6A reduction leads to increased accumulation of repeat RNA and poly-dipeptides. Moreover, the antisense RNA can also be regulated by m6A. Elevating m6A level significantly reduces both sense and antisense repeat RNA and poly-dipeptides, rescues global mRNA homeostasis, and improves survival of C9ORF72-ALS/FTD patient neurons.
2023-06-09 | GSE203580 | GEO
Project description:N6-methyladenosine (m6A) is the most prevalent internal mRNA modification and regulates RNA metabolism. Repeat expansion in C9ORF72 is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal degeneration (FTD). Here, we showed that m6A is downregulated in C9ORF72-ALS/FTD patient-derived iPSC-differentiated neurons and postmortem brain tissues. The global m6A hypomethylation leads to transcriptome-wide mRNA stabilization and upregulated gene expression, especially ones involved in synaptic activity and neuronal functions. The m6A modification in the C9ORF72 intron sequence preceding the expanded repeats enhances RNA degradation via the nuclear reader YTHDC1. The m6A reduction leads to increased accumulation of repeat RNA and poly-dipeptides. Moreover, the antisense RNA can also be regulated by m6A. Elevating m6A level significantly reduces both sense and antisense repeat RNA and poly-dipeptides, rescues global mRNA homeostasis, and improves survival of C9ORF72-ALS/FTD patient neurons.
2023-06-09 | GSE203578 | GEO
Project description:RNA sequencing analysis of human iPSC-derived neural stem cells generated from Control, C9ORF72 FTD/ALS, an isogenic control, and a C9ORF72 knockout line. The goal of this study is to determine the effects of the C9ORF72 repeat expansion on neural stem cell proliferation and differentiation.
2023-08-12 | GSE238005 | GEO
Project description:C9orf72 repeat expansions cause inherited amyotrophic lateral sclerosis/frontotemporal dementia (ALS/FTD) and result in both loss of C9orf72 protein expression and production of potentially toxic RNA and dipeptide repeat proteins. In addition to ALS/FTD, C9orf72 repeat expansions have been reported in a broad array of neurodegenerative syndromes including Alzheimer’s disease. Here we show that C9orf72 deficiency promotes loss of homeostatic signatures in microglia and transition to an inflammatory state characterized by an enhanced type I IFN signature. Furthermore, C9orf72-depleted microglia trigger age-dependent neuronal defects, in particular enhanced cortical synaptic pruning, leading to altered learning and memory behaviors in mice. Interestingly, C9orf72 deficient microglia also promote enhanced synapse loss and neuronal deficits in a mouse model of amyloid accumulation, while paradoxically improving plaque clearance. These findings suggest that altered microglial function due to decreased C9orf72 expression directly contributes to neurodegeneration in repeat expansion carriers independent of gain of function toxicities.
2022-06-15 | GSE164674 | GEO
Project description:Neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), are strongly influenced by inherited genetic variation, but environmental and epigenetic factors also play key roles in the course of these diseases. A hexanucleotide repeat expansion in the C9orf72 (C9) gene is the most common genetic cause of ALS and FTD. To determine the cellular alterations associated with the C9 repeat expansion, we performed single nucleus transcriptomics (snRNA-seq) and epigenomics (snATAC-seq) in postmortem samples of motor and frontal cortices from C9-ALS and C9-FTD donors. We found pervasive alterations of gene expression across multiple cortical cell types in C9-ALS, with the largest number of affected genes in astrocytes and excitatory neurons. Astrocytes increased expression of markers of activation and pathways associated with structural remodeling. Excitatory neurons in upper and deep layers increased expression of genes related to proteostasis, metabolism, and protein expression, and decreased expression of genes related to neuronal function. Epigenetic analyses revealed concordant changes in chromatin accessibility, histone modifications, and gene expression in specific cell types. C9-FTD patients had a distinct pattern of changes, including loss of neurons in frontal cortex and altered expression of thousands of genes in astrocytes and oligodendrocyte-lineage cells. Overall, these findings demonstrate a context-dependent molecular disruption in C9-ALS and C9-FTD, resulting in distinct effects across cell types, brain regions, and disease phenotypes.
2023-07-17 | GSE219280 | GEO