Integrative analysis identifies key molecular signatures underlying neurodevelopmental deficits in fragile X syndrome
Ontology highlight
ABSTRACT:
INSTRUMENT(S): Q Exactive HF-X
ORGANISM(S): Homo Sapiens (human)
TISSUE(S): Central Nervous System Neuron, Cell Culture
DISEASE(S): Fragile X Syndrome
SUBMITTER: 
Niels Henning Skotte
LAB HEAD: Mahmoud Pouladi
PROVIDER: PXD011630 | Pride | 2020-06-18
REPOSITORIES: Pride
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Project description:Fragile X Syndrome (FXS) is a neurodevelopmental disorder caused by epigenetic silencing of FMR1 and loss of FMRP expression. Here we describe the establishment of an isogenic human pluripotent embryonic stem cell model of FXS. Using CRISPR/Cas9 to introduce indels in exon 3 of FMR1 and result in complete loss of FMRP (FMR1KO). We show that FMRP-deficient neurons exhibit a number of phenotypic abnormalities including neurite outgrowth and branching deficits and impaired electrophysiological network activity as measured by multi-electrode arrays. RNA-Seq analysis of FMRP-deficient neurons revealed transcriptional dysregulation in pathways related to neurodevelopment, neurotransmission, and the cell cycle
2020-06-09 | PXD011445 | Pride
Project description:Fragile X syndrome (FXS) is a rare disease but is the most common form of inherited intellectual disability and a leading cause of autism. FXS is due to the absence of the Fragile X Mental Retardation Protein (FMRP), an RNA-binding protein mainly involved in translational control. Even if this molecular defect is known, no specific therapy is available for FXS. The first alteration observed in the brain of FXS patients and of Fmr1 KO mice, model for FXS, is represented by an abnormal dendritic morphology that is associated with an altered synaptic plasticity. These findings led to numerous studies focused on mature neurons. However, recently, an increasing body of evidence is pointing out the importance of FMRP in the early steps of brain development. Thus, with the purpose to decipher the earliest molecular events leading to FXS we developed a stem-cell-based disease model by knocking-down the expression of Fmr1 in mouse embryonic stem (ES) cells. To gain insights in the pathways that are affected when FMRP is repressed, we performed a gene expression profile analysis comparing total RNA from shFmr1 and shControl ES cells using whole genome mouse microarrays. Transcripts were clustered according to their Gene Ontology classification using the DAVID software. Surprisingly, the most altered functional category was Nervous system development and function, highlighting the role of FMRP also during the earliest steps of neural development. To study the precise role of FMRP in Embryonic stem (ES) cells, we used an RNAi-based loss-of-function strategy by transducing mouse ES cells with a lentivirus expressing GFP and a shRNA targeting the constitutive exon 1 of Fmr1 (shFmr1). A random shRNA (shCT) was used as a control sequence. Transduced cells were sorted by flow cytometry and established as non-clonal cell populations. RNA samples were harvested and profiling experiments were performed in â??dye-balanceâ?? as indicated for each replicate.
2016-07-04 | E-GEOD-71184 | biostudies-arrayexpress
Project description:Fragile-X Syndrome (FXS) is a multi-organ disease leading to mental retardation, macro-orchidism in males, and premature ovarian insufficiency in female carriers. FXS is also a prominent monogenic disease associated with autism spectrum disorders (ASD). FXS is typically caused by the loss of FRAGILE X-MENTAL RETARDATION 1 (FMR1) expression, which encodes for the RNA-binding protein (RBP), FMR1 (or FMRP). We report the discovery of the RNA recognition elements (RREs), binding sites, and mRNA targets for wild-type and I304N mutant FMRP isoforms as well as its paralogs, FXR1 and FXR2. RRE frequency, ratio, and distribution determine target mRNA association with FMRP. Among highly-enriched targets, we identified many genes involved in ASD and demonstrate that FMRP can affect their protein levels in cell culture, mice, and human brain. Unexpectedly, we discovered that these targets are also dysregulated in Fmr1-/- mouse ovaries, showing signs of premature follicular overdevelopment. These results indicate that FMRP targets shared signaling pathways across different cellular contexts. As it is become increasingly appreciated that signaling pathways are important to FXS and ASD, our results here provide an invaluable molecular guide towards the pursuit of novel therapeutic targets for these devastating neurological disorders. The mRNA profile of RNA recovered from FLAG-antibody immunoprecipitated FMRP was compared to the mRNA profile of the starting lysate material.
2012-12-13 | E-GEOD-39504 | biostudies-arrayexpress
Project description:Fragile-X Syndrome (FXS) is a multi-organ disease leading to mental retardation, macro-orchidism in males, and premature ovarian insufficiency in female carriers. FXS is also a prominent monogenic disease associated with autism spectrum disorders (ASD). FXS is typically caused by the loss of FRAGILE X-MENTAL RETARDATION 1 (FMR1) expression, which encodes for the RNA-binding protein (RBP), FMR1 (or FMRP). We report the discovery of the RNA recognition elements (RREs), binding sites, and mRNA targets for wild-type and I304N mutant FMRP isoforms as well as its paralogs, FXR1 and FXR2. RRE frequency, ratio, and distribution determine target mRNA association with FMRP. Among highly-enriched targets, we identified many genes involved in ASD and demonstrate that FMRP can affect their protein levels in cell culture, mice, and human brain. Unexpectedly, we discovered that these targets are also dysregulated in Fmr1-/- mouse ovaries, showing signs of premature follicular overdevelopment. These results indicate that FMRP targets shared signaling pathways across different cellular contexts. As it is become increasingly appreciated that signaling pathways are important to FXS and ASD, our results here provide an invaluable molecular guide towards the pursuit of novel therapeutic targets for these devastating neurological disorders. PAR-CLIP profiling for wild-type and I304N mutant FMRP isoforms as well as paralogs, FXR1 and FXR2.
2012-12-13 | E-GEOD-39682 | biostudies-arrayexpress
Project description:Fragile X Syndrome (FXS) is a hereditary form of autism spectrum disorder. It is caused by a trinucleotide repeat expansion in the Fmr1 gene, leading to a loss of Fragile X Protein (FMRP) expression. The loss of FMRP causes auditory hypersensitivity: FXS patients display hyperacusis and the Fmr1- knock-out (KO) mouse model for FXS exhibits auditory seizures. FMRP is strongly expressed in the cochlear nucleus and other auditory brainstem nuclei. We hypothesize that the Fmr1-KO mouse has altered gene expression in the cochlear nucleus that may contribute to auditory hypersensitivity.
2023-08-01 | GSE236056 | GEO
Project description:Aberrant alternative splicing of mRNAs results in dysregulated gene expression in multiple neurological disorders. Here we show that hundreds of mRNAs are incorrectly expressed and spliced in white blood cells and brain tissue of individuals with fragile X syndrome (FXS). Surprisingly, the FMR1 (Fragile X Messenger Ribonucleoprotein 1) gene is transcribed in >70% of the FXS tissues. In all FMR1 expressing FXS tissues, FMR1 RNA itself is mis-spliced in a CGG expansion-dependent manner to generate the little-known FMR1-217 RNA isoform, which is comprised of FMR1 exon 1 and a pseudo-exon in intron 1. FMR1-217 is also expressed in FXS premutation carrier-derived skin fibroblasts and brain tissue. We show that in cells aberrantly expressing mis-spliced FMR1, antisense oligonucleotide (ASO) treatment reduces FMR1-217, rescues full-length FMR1 RNA, and restores FMRP (Fragile X Messenger RibonucleoProtein) to normal levels. Notably, FMR1 gene reactivation in transcriptionally silent FXS cells using 5-aza-2′-deoxycytidine (5-AzadC), which prevents DNA methylation, increases FMR1-217 RNA levels but not FMRP. ASO treatment of cells prior to 5-AzadC application rescues full-length FMR1 expression and restores FMRP. These findings indicate that mis-regulated RNA processing events in blood could serve as potent biomarkers for FXS and that in those individuals expressing FMR1-217, ASO treatment may offer a new therapeutic approach to mitigate the disorder.
2023-06-14 | GSE202178 | GEO
Project description:Aberrant alternative splicing of mRNAs results in dysregulated gene expression in multiple neurological disorders. Here we show that hundreds of mRNAs are incorrectly expressed and spliced in white blood cells and brain tissue of individuals with fragile X syndrome (FXS). Surprisingly, the FMR1 (Fragile X Messenger Ribonucleoprotein 1) gene is transcribed in >70% of the FXS tissues. In all FMR1 expressing FXS tissues, FMR1 RNA itself is mis-spliced in a CGG expansion-dependent manner to generate the little-known FMR1-217 RNA isoform, which is comprised of FMR1 exon 1 and a pseudo-exon in intron 1. FMR1-217 is also expressed in FXS premutation carrier-derived skin fibroblasts and brain tissue. We show that in cells aberrantly expressing mis-spliced FMR1, antisense oligonucleotide (ASO) treatment reduces FMR1-217, rescues full-length FMR1 RNA, and restores FMRP (Fragile X Messenger RibonucleoProtein) to normal levels. Notably, FMR1 gene reactivation in transcriptionally silent FXS cells using 5-aza-2′-deoxycytidine (5-AzadC), which prevents DNA methylation, increases FMR1-217 RNA levels but not FMRP. ASO treatment of cells prior to 5-AzadC application rescues full-length FMR1 expression and restores FMRP. These findings indicate that mis-regulated RNA processing events in blood could serve as potent biomarkers for FXS and that in those individuals expressing FMR1-217, ASO treatment may offer a new therapeutic approach to mitigate the disorder.
2023-06-14 | GSE202177 | GEO
Project description:Fragile X syndrome (FXS) is caused by the absence of the fragile X mental retardation protein (FMRP). We have previously generated FXS-induced pluripotent stem cells (iPSCs) from patients' fibroblasts. In this study, we aimed at unraveling the molecular phenotype of the disease. Our data revealed aberrant regulation of neural differentiation and axon guidance genes in FXS-derived neurons, which are regulated by the RE-1 silencing transcription factor (REST). Moreover, we found REST to be elevated in FXS-derived neurons. As FMRP is involved in the microRNA (miRNA) pathway we employed microRNA-array analyses and uncovered several miRNAs dysregulated in FXS-derived neurons. We found hsa-mir-382 to be down-regulated in FXS-derived neurons, and introduction of mimic-mir-382 into these neurons was sufficient to repress REST and up-regulate its axon guidance target genes. Our data link, FMRP and REST, through the miRNA pathway, and show a new aspect in the development of FXS. Affimetrix miRNA array of two WT and two fragile X syndrome derived neurons
2014-10-28 | E-GEOD-62721 | biostudies-arrayexpress
Project description:Fragile X syndrome (FXS) is caused by inactivation of FMR1 gene and loss of its encoded product the RNA binding protein FMRP, which generally represses translation of its target transcripts in the brain. In mouse models of FXS (i.e., Fmr1 knockout animals; Fmr1 KO), deletion of Cpeb1, which encodes a translational activator, mitigates nearly all pathophysiologies associated with the disorder. Here we reveal unexpected wide-spread dys-regulation of RNA abundance in Fmr1 KO brain cortex and its rescue to normal levels in Fmr1/Cpeb1 double KO mice. Alteration and restoration of RNA levels are the dominant molecular events that drive the observed dys-regulation and rescue of translation as measured by whole transcriptome ribosome occupany in the brain. The RNAs down-regulated and rescued in these animal models are highly enriched for FMRP binding targets and have an optimal codon bias that would predict their stability in wild type and possible instability in FMRP knock-out brain. These results leads to a further study to profile RNA metabolism rates in Fragile X neurons.
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Project description:Fragile X syndrome (FXS) is caused by transcriptional silencing of the FMR1 gene during embryonic development with the consequent loss of the encoded fragile X mental retardation protein (FMRP). The pathological mechanisms of FXS have been extensively studied using the Fmr1-knockout mouse, and the findings suggest important roles for FMRP in synaptic plasticity and proper functioning of neural networks. However, the function of FMRP during early neural development in human nervous systems remains to be confirmed. We established human neural progenitor cells (NPCs) as a model for studying FMRP functions and FXS pathology. In order to identify the differentially expressed genes in FMR1KO-NPCs, we performed DNA array analysis on this model.
2018-08-07 | GSE108560 | GEO