The C9ORF72 Repeat Epansion Impairs Neurodevelopment
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE238005 | GEO | 2023/08/12
REPOSITORIES: GEO
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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:To differentiate, characterize and examine intrinsic phenotypes of C9orf72 ALS/FTD patient-derived induced pluripotent stem cells into microglia (iPSC-MG). Moderate molecular and functional differences were observed in C9orf72 iPSC-MG mono-cultures despite the presence of C9orf72 pathological features.
2023-05-23 | GSE233262 | GEO
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:Hexanucleotide repeat expansion in the C9ORF72 gene is the most frequent inherited cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Poly-GR is one of the most toxic dipeptide repeat (DPR) proteins translated from the RNA repeats. It has been shown to affect protein synthesis, but how this contributes to neurodegeneration is not clear. Here, we found that poly-GR inhibits global translation by perturbing translation elongation. We identified that the transcripts with relatively slow elongation rate tend to be further stalled by poly-GR in iPSC-differentiated neurons. This increases ribosome collision and ZAKα-mediated ribotoxic stress response (RSR), which elevates the phosphorylation of p38 and promotes cell death. Knockdown of ZAKα or pharmacological inhibition of p38 can ameliorate the GR toxicity, and improve the survival of C9ORF72-ALS/FTD patient-derived iPSC-neurons. Our study reveals molecular mechanism of poly-GR mediated toxicity on global translatome, and identifies RSR as a potential therapeutic target for C9ORF72-ALS/FTD.
2024-08-23 | GSE230127 | GEO
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:Importance: An intronic hexanucleotide repeat expansion (HRE) in C9orf72 is the commonest monogenic cause of the neurodegenerative diseases amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Predicting those who will develop neurodegeneration and its timing will be essential to initiating and assessing preventative therapy. This requires consideration of both compensatory, protective mechanisms and pathogenic events prior to overt neurodegeneration. Objective: To identify biochemical changes in individuals at higher risk of developing ALS or FTD via C9orf72 HRE heterozygosity. Design: Cross sectional observational study. Setting: Tertiary ALS or dementia referral centre. Participants: People with established ALS or FTD, either due to C9orf72 HRE or apparently sporadic cases; asymptomatic first-degree relatives of those with a known C9orf72 HRE; asymptomatic non-carrier controls. Exposure: C9orf72 HRE. Main outcomes: Relative abundance of 30 predefined cerebrospinal fluid biomarkers of ALS and FTD comparing asymptomatic C9orf72 HRE carriers and age-matched non-carriers. Differential abundance of proteins quantified using data independent acquisition mass spectrometry and neurofilament light chain measured by electrochemiluminescent assay. Results: Data for 19 people with sporadic ALS, 10 people with C9orf72 ALS, 14 people with sporadic FTD, 10 people with C9orf72 FTD, 48 asymptomatic C9orf72 HRE carriers and 39 non-carrier controls were analysed. Ubiquitin carboxyl-hydrolase isozyme L1 levels were higher in asymptomatic C9orf72 HRE carriers compared with age-matched non-carriers (log2fold change 0.20, FDR-adjusted p-value = 0.034). Neurofilament light chain levels did not differ significantly between groups. Ubiquitin carboxyl-hydrolase isozyme L1 levels remained elevated after exclusion of those with high neurofilament light chain levels, after adjusting for NFL level and after adjusting for age. Conclusions and relevance: Elevated cerebrospinal fluid ubiquitin carboxyl-hydrolase isozyme L1 levels in C9orf72 hexanucleotide repeat expansion carriers occurs in the absence of elevation in neurofilament light chain, potentially reflecting mechanisms that precede the phase of neurodegeneration characterised by rapid neuronal loss. Such mechanisms may have either compensatory or pathogenic roles. Ubiquitin carboxyl-terminal hydrolase isozyme L1 elevation brings forward the window on the changes associated with the C9orf72 HRE carrier state, with the potential to inform understanding penetrance and approaches to prevention.
2024-11-19 | PXD051859 | Pride
Project description:The C9ORF72 Repeat Epansion Impairs Neurodevelopment
| PRJNA997823 | ENA
Project description:Microsatellite repeat expansion disease loci can exhibit pleiotropic clinical and biological effects depending on repeat length. Large expansions in C9orf72 (100s-1000s of units) are the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal degeneration (FTD). However, whether intermediate expansions also contribute to neurodegenerative disease is not well understood. Several studies have identified intermediate repeats in Parkinson’s disease patients, but the association was not found in autopsy confirmed cases. We hypothesized that intermediate C9orf72 repeats are a genetic risk factor for corticobasal degeneration (CBD), a neurodegenerative disease that can be clinically similar to Parkinson’s but has distinct tau protein pathology. Indeed, intermediate C9orf72 repeats were significantly enriched in autopsy-proven CBD (n=354 cases, odds ratio=3.59, p-value=0.00024). While large C9orf72 repeat expansions are known to decrease C9orf72 expression, intermediate C9orf72 repeats result in increased C9orf72 expression in human brain tissue and CRISPR/cas9 knockin iPSC derived neural progenitor cells. In contrast to cases of FTD/ALS with large C9orf72 expansions, CBD with intermediate C9orf72 repeats was not associated with pathologic RNA foci or dipeptide repeat protein aggregates. Knock-in cells with intermediate repeats exhibit numerous changes in gene expression pathways relating to vesicle trafficking and autophagy. Additionally, overexpression of C9orf72 without the repeat expansion leads to defects in autophagy under nutrient starvation conditions. These results raise the possibility that therapeutic strategies to reduce C9orf72 expression may be beneficial for the treatment of CBD.
2019-09-17 | GSE133323 | GEO
Project description:Purpose: The purpose of this experiment is to identify a C9-ALS/FTD specific genomic profile in fibroblast lines that is distinct from sporadic ALS without C9orf72 expansion and non-neurologic control cells. The study will then evaluate the effect on this identified profile of ASO treatment targeting the sense strand RNA transcript of the C9orf72 gene. Methods: Expression profiling was performed on RNAs from fibroblasts of four C9orf72 patients, four control individuals and four sporadic ALS patients using Multiplex Analysis of PolyA-linked Sequences method. Results: Hierarchical clustering of expression values for all genes showed that the four C9orf72 patient lines had an expression profile distinct from control and sporadic ALS lines. Statistical comparison of expression values between the four C9orf72 lines and the four control lines revealed that 122 genes were upregulated (defined by a False Discovery Rate FDR<0.05) and 34 genes were downregulated (defined by a False Discovery Rate FDR <0.05) in C9orf72 patient fibroblasts. Conclusions: A genome wide RNA signature can be defined in fibroblasts with C9orf72 expansion. ASO-mediated reduction of C9orf72 RNA levels in fibroblasts with the hexanucleotide expansion efficiently reduced accumulation of GGGGCC RNA foci. This did not, however, generate a reversal of the C9orf72 RNA profile. Use of Multiplex Analysis of PolyA-linked Sequences to identify expression changes in fibroblasts from amyotrophic lateral sclerosis and frontotemporal dementia patients harboring an hexanucleotide expansion in the C9orf72 gene.
2013-11-12 | E-GEOD-51684 | biostudies-arrayexpress
Project description:An abnormal expansion of a GGGGCC hexanucleotide repeat in the C9ORF72 gene is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), two debilitating neurodegenerative disorders driven in part by gain-of-function mechanisms involving transcribed forms of the repeat expansion. By utilizing a Cas13 variant with reduced collateral effects, we developed a high-fidelity RNA-targeting CRISPR-based system for C9ORF72-linked ALS/FTD. When delivered to the brain of a transgenic rodent model, this Cas13-based platform effectively curbed the expression of the GGGGCC repeat-containing RNA without affecting normal C9ORF72 levels, which in turn decreased the formation of RNA foci and reversed transcriptional deficits. This high-fidelity Cas13 variant possessed improved transcriptome-wide specificity compared to its native form and mediated efficient targeting in motor neuron-like cells derived from a patient with ALS. Our results lay the foundation for the implementation of RNA-targeting CRISPR technologies for C9ORF72-linked ALS/FTD.
2024-12-08 | GSE283702 | GEO