C9orf72 expansion creates the unstable folate-sensitive fragile site FRA9A
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PROVIDER: PRJNA1092954 | ENA |
REPOSITORIES: ENA
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Project description:The hyper-unstable Chr9p21 locus, harbouring the interferon gene cluster, oncogenes and C9orf72, is linked to multiple diseases. C9orf72 (GGGGCC)n expansions (C9orf72Exp) are associated with incompletely penetrant amyotrophic lateral sclerosis, frontotemporal dementia and autoimmune disorders. C9orf72Exp patients display hyperactive cGAS-STING-linked interferon immune and DNA damage responses, but the source of immuno-stimulatory or damaged DNA is unknown. Here, we show C9orf72Exp in pre-symptomatic and ALS-FTD patient cells and brains cause the folate-sensitive chromosomal fragile site, FRA9A. FRA9A centers on > 33kb of C9orf72 as highly-compacted chromatin embedded in an 8.2Mb fragility zone spanning 9p21, encompassing 46 genes, making FRA9A one of the largest fragile sites. C9orf72Exp cells show chromosomal instability, heightened global- and Chr9p-enriched sister-chromatid exchanges, truncated-Chr9s, acentric-Chr9s and Chr9-containing micronuclei, providing endogenous sources of damaged and immunostimulatory DNA. Cells from one C9orf72Exp patient contained highly-rearranged FRA9A-expressing Chr9 with Chr9-wide dysregulated gene expression. Somatic C9orf72Exp repeat instability and chromosomal fragility are sensitive to folate-deficiency. Age-dependent repeat instability, chromosomal fragility, and chromosomal instability can be transferred to CNS and peripheral tissues of transgenic C9orf72Exp mice, implicating C9orf72Exp as the source. Our results highlight unappreciated effects of C9orf72 expansions that trigger vitamin-sensitive chromosome fragility, adding structural variations to the disease-enriched 9p21 locus, and likely elsewhere.
2024-11-26 | GSE262674 | GEO
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| PRJDB12971 | 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:Noncoding expansions of a hexanucleotide repeat (GGGGCC) in the C9orf72 gene are the most common cause of familial amyotrophic lateral sclerosis and frontotemporal dementia. Here we report transgenic mice carrying a bacterial artificial chromosome (BAC) containing the full human C9orf72 gene with either a normal allele (15 repeats) or disease-associated expansion (~100â??1,000 repeats; C9-BACexp). C9-BACexp mice displayed pathologic features seen in C9orf72 expansion patients, including widespread RNA foci and repeat-associated non-ATG (RAN) translated dipeptides, which were suppressed by antisense oligonucleotides targeting human C9orf72. Nucleolin distribution was altered, supporting that either C9orf72 transcripts or RAN dipeptides promote nucleolar dysfunction. Despite early and widespread production of RNA foci and RAN dipeptides in C9-BACexp mice, behavioral abnormalities and neurodegeneration were not observed even at advanced ages, supporting the hypothesis that RNA foci and RAN dipeptides occur presymptomatically and are not sufficient to drive neurodegeneration in mice at levels seen in patients. To compare the RNA Seq profiles from the cortex and spinal cord of transgenic mice expressing unexpanded human C9orf72 (F08, n=4), expanded human C9orf72 (F112, n=3/4), and nontransgenic controls (n=4).
2016-02-10 | E-GEOD-77720 | 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: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:The rupture of unstable atherosclerotic plaques, leading to debilitating or fatal thrombotic events, is a major health burden worldwide. Limited understanding as to the molecular drivers of plaque instability and rupture hinders efforts in diagnosis and treatment prior to thrombotic events. Utilising an advanced pre-clinical mouse model (Tandem stenosis (TS) model), which presents human-like unstable atherosclerotic disease, we apply high-end omic methods to characterize the molecular signatures associated with plaque instability in atherosclerotic arteries. Through quantitative proteomic profiling, we depict unique proteome signatures of unstable plaques compared to stable plaques and healthy arteries. Coupled with single-cell RNA-sequencing of leukocytes, we describe the heterodimer complex S100a8/S100a9 as unique to unstable plaque, with neutrophils implicated as the transcriptional drivers of S100a8/a9 expression. We confirm S100a9 expression in human carotid atherosclerotic plaques and we further utilise the TS pre-clinical model to pharmacologically inhibit S100a8/S100a9, resulting in plaque stabilisation. Thus, we establish the TS model as a sophisticated translational tool for the profiling of unstable atherosclerotic plaques and demonstrate that unstable and stable atherosclerosis are highly different disease entities.
2023-05-10 | PXD030857 | Pride
Project description:Expansions of a hexanucleotide repeat (GGGGCC) in the noncoding region of the C9orf72 gene are the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia. Decreased expression of C9orf72 is seen in expansion carriers, suggesting loss of function may play a role in disease. We find that two independent mouse lines lacking the C9orf72 ortholog (3110043O21Rik) in all tissues developed normally and aged without motor neuron disease. Instead, C9orf72 null mice developed progressive splenomegaly and lymphadenopathy with accumulation of engorged macrophage-like cells. C9orf72 expression was highest in myeloid cells, and loss of C9orf72 led to lysosomal accumulation and altered immune responses in macrophages and microglia, with age-related neuroinflammation similar to C9orf72 ALS but not sporadic ALS patient tissue. Thus, C9orf72 is required for normal function of myeloid cells, and altered microglial function may contribute to neurodegeneration in C9orf72 expansion carriers.
2016-03-24 | GSE77681 | GEO