Project description:Abnormal trinucleotide expansions cause rare disorders that compromise quality of life and, in some cases, life span. In particular, the expansions of the CGG-repeats stretch at the 5'-UTR of the Fragile X Mental Retardation 1 (FMR1) gene have pleiotropic effects that lead to a variety of Fragile X-associated syndromes: the neurodevelopmental Fragile X syndrome (FXS) in children, the late-onset neurodegenerative disorder Fragile X-associated tremor-ataxia syndrome (FXTAS) that mainly affects adult men, the Fragile X-associated primary ovarian insufficiency (FXPOI) in adult women, and a variety of psychiatric and affective disorders that are under the term of Fragile X-associated neuropsychiatric disorders (FXAND). There have been intensive attempts to identify reliable peripheral biomarkers to assess disease progression and onset of specific pathological traits. We profiled the miRNAs content of plasma from premutation carriers and controls. Understanding the association between molecular pathogenesis and biomarkers dynamics will improve effective prognosis and clinical management of CGG-expansion carriers
Project description:Fragile X premutation carriers (fXPC) of the CGG expansion in the 5M-bM-^@M-^Y-UTR of the fragile X mental retardation 1 (FMR1) gene are at high risk of Fragile X Tremor/Ataxia Syndrome (FXTAS), and females might undergo Premature Ovarian Failure (POF1). We have evaluated the peripheral blood gene expression profiles of fXPC and detected a strong deregulation of genes enriched in FXTAS-relevant biological pathways, including inflammation, and neuronal homeostasis and survival. More than 30% of differentially expressed correspond to long non-coding RNAs (lncRNAs). Several deregulated genes (CASP3, DFFA, APP, AKT1, COX6C, COX7B, SOD1, RNF10, HDAC5, ATXN7, ATXN3 and EAP1) were validated in brain samples of a mouse model of FXTAS and in neuronal cells expressing the expanded FMR1 5M-bM-^@M-^Y-UTR. One of the validated genes is the early at menopause 1 (EAP1) gene. We confirmed the EAP1 deregulation both in male and female fXPC. Down-regulation was stronger in female fXPC with POF1 compared with female fXPC without POF1. Increased levels of FMR1 mRNA were detected in all brain areas of the CGG-KI mouse model. EAP1 was significantly downregulated in the brainstem and cerebellum of the KI mouse, suggesting that EAP1 levels in certain brain areas could contribute to POF in this model. All together, these results suggest that gene expression profiling in blood of fXPC reflects changes in the brain transcriptome that may underlie neuropathological aspects in FXTAS and of POF. In the study presented here, we have 5 control samples plus one biological replicate and 9 patients with CGG expansions in the 5'UTR of the FMR1 gene (being premutation carriers)
Project description:Short nucleotide repeats are robustly distributed in human genome and contribute to pathogenesis of multiple neurodegenerative disorders such as Fragile X-associated Tremor/Ataxia Syndrome (FXTAS). Pathogenesis of FXTAS is driven by premutation status of CGG repeats expansion (CGGexp) in the 5’UTR region of fragile X messenger ribonucleoprotein 1 (FMR1) gene, when CGG triplet varies between 55-200. One of the proposed molecular mechanism involved in disease progression is repeats associated non-AUG (RAN) translation, which results in the production of toxic aggregation-prone protein called FMRpolyG. Mechanistic insights of RAN translation remain elusive, therefore we aimed to identify novel RAN translation modifiers. In order to identify factors involved in FMRpolyG synthesis we applied RNA-tagging system combined with mass spectrometry (MS) based protein identification to elucidate pool of proteins natively bound to FMR1 transcript harboring CGGexp mimicking FXTAS premutation status. As a control RNAm we used construct enriched with G and C nucleotides (named GCrich RNA) to mimic GC content in investigated FMR1 mRNA. Overall, performed MS-based screening revealed novel proteins which bind specifically to 5’UTR of FMR1 with CGGexp in cellulo.
Project description:Fragile X premutation carriers (fXPC) of the CGG expansion in the 5M-bM-^@M-^Y-UTR of the fragile X mental retardation 1 (FMR1) gene are at high risk of Fragile X Tremor/Ataxia Syndrome (FXTAS), and females might undergo Premature Ovarian Failure (POF1). We have evaluated the peripheral blood gene expression profiles of fXPC and detected a strong deregulation of genes enriched in FXTAS-relevant biological pathways, including inflammation, and neuronal homeostasis and survival. More than 30% of differentially expressed correspond to long non-coding RNAs (lncRNAs). Several deregulated genes (CASP3, DFFA, APP, AKT1, COX6C, COX7B, SOD1, RNF10, HDAC5, ATXN7, ATXN3 and EAP1) were validated in brain samples of a mouse model of FXTAS and in neuronal cells expressing the expanded FMR1 5M-bM-^@M-^Y-UTR. One of the validated genes is the early at menopause 1 (EAP1) gene. We confirmed the EAP1 deregulation both in male and female fXPC. Down-regulation was stronger in female fXPC with POF1 compared with female fXPC without POF1. Increased levels of FMR1 mRNA were detected in all brain areas of the CGG-KI mouse model. EAP1 was significantly downregulated in the brainstem and cerebellum of the KI mouse, suggesting that EAP1 levels in certain brain areas could contribute to POF in this model. All together, these results suggest that gene expression profiling in blood of fXPC reflects changes in the brain transcriptome that may underlie neuropathological aspects in FXTAS and of POF. In the study presented here, we have 6 biological replicats for the Mock conditions, 6 biological replicates for the expression of the wild type FMR1 5'UTR, 6 biological replicates for the expression of the mutant FMR1 5'UTR and 6 biological replicates for the overexpression of the muatnt FMR1 5'UTR.
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.
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.
Project description:Fragile X premutation carriers (fXPC) of the CGG expansion in the 5’-UTR of the fragile X mental retardation 1 (FMR1) gene are at high risk of Fragile X Tremor/Ataxia Syndrome (FXTAS), and females might undergo Premature Ovarian Failure (POF1). We have evaluated the peripheral blood gene expression profiles of fXPC and detected a strong deregulation of genes enriched in FXTAS-relevant biological pathways, including inflammation, and neuronal homeostasis and survival. More than 30% of differentially expressed correspond to long non-coding RNAs (lncRNAs). Several deregulated genes (CASP3, DFFA, APP, AKT1, COX6C, COX7B, SOD1, RNF10, HDAC5, ATXN7, ATXN3 and EAP1) were validated in brain samples of a mouse model of FXTAS and in neuronal cells expressing the expanded FMR1 5’-UTR. One of the validated genes is the early at menopause 1 (EAP1) gene. We confirmed the EAP1 deregulation both in male and female fXPC. Down-regulation was stronger in female fXPC with POF1 compared with female fXPC without POF1. Increased levels of FMR1 mRNA were detected in all brain areas of the CGG-KI mouse model. EAP1 was significantly downregulated in the brainstem and cerebellum of the KI mouse, suggesting that EAP1 levels in certain brain areas could contribute to POF in this model. All together, these results suggest that gene expression profiling in blood of fXPC reflects changes in the brain transcriptome that may underlie neuropathological aspects in FXTAS and of POF.
Project description:Fragile X premutation carriers (fXPC) of the CGG expansion in the 5’-UTR of the fragile X mental retardation 1 (FMR1) gene are at high risk of Fragile X Tremor/Ataxia Syndrome (FXTAS), and females might undergo Premature Ovarian Failure (POF1). We have evaluated the peripheral blood gene expression profiles of fXPC and detected a strong deregulation of genes enriched in FXTAS-relevant biological pathways, including inflammation, and neuronal homeostasis and survival. More than 30% of differentially expressed correspond to long non-coding RNAs (lncRNAs). Several deregulated genes (CASP3, DFFA, APP, AKT1, COX6C, COX7B, SOD1, RNF10, HDAC5, ATXN7, ATXN3 and EAP1) were validated in brain samples of a mouse model of FXTAS and in neuronal cells expressing the expanded FMR1 5’-UTR. One of the validated genes is the early at menopause 1 (EAP1) gene. We confirmed the EAP1 deregulation both in male and female fXPC. Down-regulation was stronger in female fXPC with POF1 compared with female fXPC without POF1. Increased levels of FMR1 mRNA were detected in all brain areas of the CGG-KI mouse model. EAP1 was significantly downregulated in the brainstem and cerebellum of the KI mouse, suggesting that EAP1 levels in certain brain areas could contribute to POF in this model. All together, these results suggest that gene expression profiling in blood of fXPC reflects changes in the brain transcriptome that may underlie neuropathological aspects in FXTAS and of POF.
Project description:While FMR1 is silenced in Fragile X syndrome (FXS), its expression is elevated (2-8 fold) in premutated individuals. These people may develop the Fragile X-associated Tremor Ataxia Syndrome (FXTAS), a late onset neurodegenerative disorder characterized by ataxia and parkinsonism. In addition, people carrying the premutation can be affected by a set of neurological and behavioural disorders during young age. Problems of memory have been detected in these patients as well in the mice model for FXTAS. To date little is known concerning the metabolism of FMR1 mRNA, notwithstanding the importance of the finely tuned regulation of the expression of this gene. In the present study we identified three microRNAs that specifically target the 3’UTR of FMR1 and can modulate its expression throughout the brain and, in particular, at the synaptic level. The expression level of miR-221 is reduced in brain and synaptosomal preparations of young FXTAS mice suggesting a general deregulation of transcripts located at the synapse of these mice. By transcriptome analysis we show here a robust deregulation of the expression levels of genes involved in learning, memory and autistic behavior, Parkinson disease and neurodegeneration. Interestingly, many of those deregulated mRNAs are target of the same miRNAs that modulate the expression of FMR1 at the synapse. Knock-In versus Wild Type, 3 replicates.