Human iPSC-derived astrocytes from ALS patients with mutated C9ORF72 show increased oxidative stress and neurotoxicity
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PROVIDER: PRJNA598137 | ENA |
REPOSITORIES: ENA
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Project description:Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that affects motor neurons (MNs). It was shown that human astrocytes with mutations in genes associated with ALS, like C9orf72 (C9) or SOD1, reduce survival of MNs. Astrocyte toxicity may be related to their dysfunction or the release of neurotoxic factors. We used human induced pluripotent stem cell-derived astrocytes from ALS patients carrying C9orf72 mutations and non-affected donors. We utilized these cells to investigate astrocytic induced neuronal toxicity, changes in astrocyte transcription profile as well as changes in secretome profiles. We report that C9-mutated astrocytes are toxic to MNs via soluble factors. The toxic effects of astrocytes are positively correlated with the length of astrocyte propagation in culture, consistent with the age-related nature of ALS. We show that C9-mutated astrocytes downregulate the secretion of several antioxidant proteins. In line with these findings, we show increased astrocytic oxidative stress and senescence. Importantly, media conditioned by C9-astrocytes increased oxidative stress in wild type MNs. Our results suggest that dysfunction of C9-astrocytes leads to oxidative stress of themselves and MNs, which probably contributes to neurodegeneration. Our findings suggest that therapeutic strategies in familial ALS must not only target MNs but also focus on astrocytes to abrogate nervous system injury.
2020-06-01 | GSE142730 | GEO
Project description:Amyotrophic lateral sclerosis (ALS) is a deleterious neurodegenerative disease without effective treatment options. Recent studies have indicated the involvement of the dysregulation of RNA metabolism in the pathogenesis of ALS. Among the various RNA regulatory machineries, nonsense-mediated mRNA decay (NMD) is a stress responsive cellular surveillance system that degrades selected mRNA substrates to prevent the translation of defective or harmful proteins. Whether this pathway is affected in neurodegenerative diseases is unclear. Here we report that the NMD pathway is inhibited in ALS patients with C9orf72 hexanucleotide repeat expansion (HRE), the most common cause of familial ALS. Bioinformatic analysis of multiple transcriptome profiles revealed significant overlap of upregulated genes in NMD-defective cells with those in the brain tissues, micro-dissected motor neurons, or induced pluripotent stem cell-derived motor neurons from ALS patients carrying C9orf72 HRE, suggesting the suppression of NMD pathway in these patients. In contrast, there are few overlapping upregulated genes in brain tissues from sporadic ALS patients with those in NMD-defective cells. Using Drosophila models expressing various C9orf72 HRE products, we have validated the suppression of the NMD pathway by C9orf72 HRE and identified arginine-rich dipeptide repeats (DPRs) generated from HRE as the main culprits of NMD inhibition. Furthermore, in human SH-SY5Y neuroblastoma cells and in mouse brains, expression of arginine-rich DPRs was sufficient to cause NMD inhibition. Remarkably, expression of UPF1, a core gene in the NMD pathway, efficiently blocked neurotoxicity caused by arginine-rich DPRs in both cellular and Drosophila models. Although not as effective as UPF1, expression of another NMD gene UPF2 also ameliorated the degenerative phenotypes in DPR-expressing flies, indicating neuroprotection by genetically reactivating the NMD pathway. Finally, after validating Tranilast as an NMD-activating drug, we demonstrated its therapeutic potential in cellular and Drosophila models of C9orf72 DPR neurotoxicity. Therefore, our study has revealed the suppression of NMD in C9orf72 ALS and has suggested that the restoration of the NMD pathway by Tranilast, an asthma drug with solid safety record, could be a promising therapeutic strategy for ALS.
2018-12-01 | GSE123172 | GEO
Project description: Not available
| S-EPMC6921360 | biostudies-literature
Project description:Increasing evidence suggests that defective RNA processing contributes to the development of amyotrophic lateral sclerosis (ALS). This may be especially true for ALS caused by a repeat expansion in C9orf72 (c9ALS), in which the accumulation of RNA foci and dipeptide-repeat proteins are expected to modify RNA metabolism. We report extensive alternative splicing (AS) and alternative polyadenylation (APA) defects in the cerebellum of c9ALS cases (8,224 AS, 1,437 APA), including changes in ALS-associated genes (e.g. ATXN2 and FUS), and cases of sporadic ALS (sALS; 2,229 AS, 716 APA). Furthermore, hnRNPH and other RNA-binding proteins are predicted as potential regulators of cassette exon AS events for both c9ALS and sALS. Co-expression and gene-association network analyses of gene expression and AS data revealed divergent pathways associated with c9ALS and sALS. Examination transcriptiome profiles in c9orf72-associated ALS, sporadic ALS and healthy control
2015-07-19 | E-GEOD-67196 | biostudies-arrayexpress
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:Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive motor neuron loss, with additional pathophysiological involvement of non-neuronal cells such as microglia. The commonest ALS-associated genetic variant is a hexanucleotide repeat expansion (HRE) mutation in C9orf72. Here, we study its consequences for microglial function using human iPSC-derived microglia. By RNA-sequencing, we identify enrichment of pathways associated with immune cell activation and cyto-/chemokines in C9orf72 HRE mutant microglia versus healthy controls, most prominently after LPS priming. Specifically, LPS-primed C9orf72 HRE mutant microglia show consistently increased expression and release of matrix metalloproteinase-9 (MMP9). LPS-primed C9orf72 HRE mutant microglia are toxic to co-cultured healthy motor neurons, which is ameliorated by concomitant application of an MMP9 inhibitor. Finally, we identify release of dipeptidyl peptidase-4 (DPP4) as a marker for MMP9-dependent microglial dysregulation in co-culture. These results demonstrate cellular dysfunction of C9orf72 HRE mutant microglia, and a non-cell-autonomous role in driving C9orf72-ALS pathophysiology in motor neurons through MMP9 signaling.
2023-08-20 | GSE217625 | 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 | 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 | GSE203578 | GEO
Project description:Amyotrophic lateral sclerosis (ALS) is a severe neurodegenerative condition characterized by loss of motor neurons in the brain and spinal cord. Expansions of a hexanucleotide repeat (GGGGCC) in the noncoding region of the C9ORF72 gene are the most common cause of the familial form of ALS (C9-ALS), as well as frontotemporal lobar degeneration and other neurological diseases. How the repeat expansion causes disease remains unclear, with both loss of function (haploinsufficiency) and gain of function (either toxic RNA or protein products) proposed. We report a cellular model of C9-ALS with motor neurons differentiated from induced pluripotent stem cells (iPSCs) derived from ALS patients carrying the C9ORF72 repeat expansion. No significant loss of C9ORF72 expression was observed, and knockdown of the transcript was not toxic to cultured human motor neurons. Transcription of the repeat was increased, leading to accumulation of GGGGCC repeat–containing RNA foci selectively in C9-ALS iPSC-derived motor neurons. Repeat-containing RNA foci colocalized with hnRNPA1 and Pur-?, suggesting that they may be able to alter RNA metabolism. C9-ALS motor neurons showed altered expression of genes involved in membrane excitability including DPP6, and demonstrated a diminished capacity to fire continuous spikes upon depolarization compared to control motor neurons. Antisense oligonucleotides targeting the C9ORF72 transcript suppressed RNA foci formation and reversed gene expression alterations in C9-ALS motor neurons. These data show that patient-derived motor neurons can be used to delineate pathogenic events in ALS. Transcriptome profiling from iPSC derived motor neurons compared to controls
2013-11-07 | E-GEOD-52202 | biostudies-arrayexpress