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Haify SN, Buijsen RAM, Verwegen L, Severijnen LAWFM, de Boer H, Boumeester V, Monshouwer R, Yang WY, Cameron MD, Willemsen R, Disney MD, Hukema RK. Small molecule 1a reduces FMRpolyG-mediated toxicity in in vitro and in vivo models for FMR1 premutation. Hum Mol Genet 2021; 30:1632-1648. [PMID: 34077515 PMCID: PMC8369842 DOI: 10.1093/hmg/ddab143] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 05/13/2021] [Accepted: 05/15/2021] [Indexed: 12/15/2022] Open
Abstract
Fragile X-associated tremor and ataxia syndrome (FXTAS) is a late-onset, progressive neurodegenerative disorder characterized by tremors, ataxia and neuropsychological problems. This disease is quite common in the general population with approximately 20 million carriers worldwide. The risk of developing FXTAS increases dramatically with age, with about 45% of male carriers over the age of 50 being affected. FXTAS is caused by a CGG-repeat expansion (CGGexp) in the fragile X mental retardation 1 (FMR1) gene. CGGexp RNA is translated into the FMRpolyG protein by a mechanism called RAN translation. Although both gene and pathogenic trigger are known, no therapeutic interventions are available at this moment. Here, we present, for the first time, primary hippocampal neurons derived from the ubiquitous inducible mouse model which is used as a screening tool for targeted interventions. A promising candidate is the repeat binding, RAN translation blocking, small molecule 1a. Small molecule 1a shields the disease-causing CGGexp from being translated into the toxic FMRpolyG protein. Primary hippocampal neurons formed FMRpolyG-positive inclusions, and upon treatment with 1a, the numbers of FMRpolyG-positive inclusions are reduced. We also describe for the first time the formation of FMRpolyG-positive inclusions in the liver of this mouse model. Treatment with 1a reduced the insoluble FMRpolyG protein fraction in the liver but not the number of inclusions. Moreover, 1a treatment had a reducing effect on the number of Rad23b-positive inclusions and insoluble Rad23b protein levels. These data suggest that targeted small molecule therapy is effective in an FXTAS mouse model and has the potential to treat CGGexp-mediated diseases, including FXTAS.
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Affiliation(s)
- Saif N Haify
- Department of Clinical Genetics, Erasmus MC, Rotterdam, the Netherlands
| | - Ronald A M Buijsen
- Department of Clinical Genetics, Erasmus MC, Rotterdam, the Netherlands.,Department of Human Genetics, LUMC, Leiden, the Netherlands
| | - Lucas Verwegen
- Department of Clinical Genetics, Erasmus MC, Rotterdam, the Netherlands.,Department of Cell Biology, Erasmus MC, Rotterdam, the Netherlands
| | | | - Helen de Boer
- Department of Clinical Genetics, Erasmus MC, Rotterdam, the Netherlands
| | | | - Roos Monshouwer
- Department of Clinical Genetics, Erasmus MC, Rotterdam, the Netherlands
| | - Wong Y Yang
- Department of Chemistry, Scripps Research Institute, Florida, the United States
| | - Michael D Cameron
- Department of Chemistry, Scripps Research Institute, Florida, the United States
| | - Rob Willemsen
- Department of Clinical Genetics, Erasmus MC, Rotterdam, the Netherlands
| | - Matthew D Disney
- Department of Chemistry, Scripps Research Institute, Florida, the United States
| | - Renate K Hukema
- Department of Clinical Genetics, Erasmus MC, Rotterdam, the Netherlands.,Department of Health Care Studies, Rotterdam University of Applied Sciences, Rotterdam, the Netherlands
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2
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Dijkstra AA, Haify SN, Verwey NA, Prins ND, van der Toorn EC, Rozemuller AJM, Bugiani M, den Dunnen WFA, Todd PK, Charlet-Berguerand N, Willemsen R, Hukema RK, Hoozemans JJM. Neuropathology of FMR1-premutation carriers presenting with dementia and neuropsychiatric symptoms. Brain Commun 2021; 3:fcab007. [PMID: 33709078 PMCID: PMC7936660 DOI: 10.1093/braincomms/fcab007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 12/15/2020] [Accepted: 12/17/2020] [Indexed: 01/07/2023] Open
Abstract
CGG repeat expansions within the premutation range (55–200) of the FMR1 gene can lead to Fragile X-associated tremor/ataxia syndrome and Fragile X-associated neuropsychiatric disorders. These CGG repeats are translated into a toxic polyglycine-containing protein, FMRpolyG. Pathology of Fragile X-associated tremor/ataxia syndrome and Fragile X-associated neuropsychiatric disorders comprises FMRpolyG- and p62-positive intranuclear inclusions. Diagnosing a FMR1-premutation carrier remains challenging, as the clinical features overlap with other neurodegenerative diseases. Here, we describe two male cases with Fragile X-associated neuropsychiatric disorders-related symptoms and mild movement disturbances and novel pathological features that can attribute to the variable phenotype. Macroscopically, both donors did not show characteristic white matter lesions on MRI; however, vascular infarcts in cortical- and sub-cortical regions were identified. Immunohistochemistry analyses revealed a high number of FMRpolyG intranuclear inclusions throughout the brain, which were also positive for p62. Importantly, we identified a novel pathological vascular phenotype with inclusions present in pericytes and endothelial cells. Although these results need to be confirmed in more cases, we propose that these vascular lesions in the brain could contribute to the complex symptomology of FMR1-premutation carriers. Overall, our report suggests that Fragile X-associated tremor/ataxia syndrome and Fragile X-associated neuropsychiatric disorders may present diverse clinical involvements resembling other types of dementia, and in the absence of genetic testing, FMRpolyG can be used post-mortem to identify premutation carriers.
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Affiliation(s)
- Anke A Dijkstra
- Department of Pathology, Amsterdam Neuroscience, Amsterdam University Medical Centre, Amsterdam, The Netherlands
| | - Saif N Haify
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Niek A Verwey
- Department of Neurology, Medisch Centrum Leeuwarden, Leeuwarden, The Netherlands
| | - Niels D Prins
- Department of Neurology, Alzheimer Center, VU University Medical Center, Amsterdam Neuroscience, The Netherlands.,Brain Research Center, Amsterdam, The Netherlands
| | | | - Annemieke J M Rozemuller
- Department of Pathology, Amsterdam Neuroscience, Amsterdam University Medical Centre, Amsterdam, The Netherlands
| | - Marianna Bugiani
- Department of Pathology, Amsterdam Neuroscience, Amsterdam University Medical Centre, Amsterdam, The Netherlands
| | - Wilfred F A den Dunnen
- Department of Pathology and Medical Biology, University Medical Center Groningen, Groningen, The Netherlands
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA.,Department of Veterans Affairs, Ann Arbor Healthcare System, Ann Arbor, MI, USA
| | - Nicolas Charlet-Berguerand
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400, Illkirch, France
| | - Rob Willemsen
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Renate K Hukema
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands.,Department of Health Care Studies, Rotterdam University of Applied Sciences, Rotterdam, The Netherlands
| | - Jeroen J M Hoozemans
- Department of Pathology, Amsterdam Neuroscience, Amsterdam University Medical Centre, Amsterdam, The Netherlands
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Haify SN, Mankoe RSD, Boumeester V, van der Toorn EC, Verhagen RFM, Willemsen R, Hukema RK, Bosman LWJ. Lack of a Clear Behavioral Phenotype in an Inducible FXTAS Mouse Model Despite the Presence of Neuronal FMRpolyG-Positive Aggregates. Front Mol Biosci 2020; 7:599101. [PMID: 33381520 PMCID: PMC7768028 DOI: 10.3389/fmolb.2020.599101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 11/23/2020] [Indexed: 11/25/2022] Open
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a rare neurodegenerative disorder caused by a 55–200 CGG repeat expansion in the 5′ untranslated region of the Fragile X Mental Retardation 1 (FMR1) gene. FXTAS is characterized by progressive cerebellar ataxia, Parkinsonism, intention tremors and cognitive decline. The main neuropathological hallmark of FXTAS is the presence of ubiquitin-positive intranuclear inclusions in neurons and astrocytes throughout the brain. The molecular pathology of FXTAS involves the presence of 2 to 8-fold elevated levels of FMR1 mRNA, and of a repeat-associated non-AUG (RAN) translated polyglycine peptide (FMRpolyG). Increased levels of FMR1 mRNA containing an expanded CGG repeat can result in cellular toxicity by an RNA gain-of-function mechanism. The increased levels of CGG repeat-expanded FMR1 transcripts may create RNA foci that sequester important cellular proteins, including RNA-binding proteins and FMRpolyG, in intranuclear inclusions. To date, it is unclear whether the FMRpolyG-positive intranuclear inclusions are a cause or a consequence of FXTAS disease pathology. In this report we studied the relation between the presence of neuronal intranuclear inclusions and behavioral deficits using an inducible mouse model for FXTAS. Neuronal intranuclear inclusions were observed 4 weeks after dox-induction. After 12 weeks, high numbers of FMRpolyG-positive intranuclear inclusions could be detected in the hippocampus and striatum, but no clear signs of behavioral deficits related to these specific brain regions were found. In conclusion, the observations in our inducible mouse model for FXTAS suggest a lack of correlation between the presence of intranuclear FMRpolyG-positive aggregates in brain regions and specific behavioral phenotypes.
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Affiliation(s)
- Saif N Haify
- Department of Clinical Genetics, Erasmus MC, Rotterdam, Netherlands
| | - Ruchira S D Mankoe
- Department of Clinical Genetics, Erasmus MC, Rotterdam, Netherlands.,Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
| | | | | | - Rob F M Verhagen
- Department of Clinical Genetics, Erasmus MC, Rotterdam, Netherlands
| | - Rob Willemsen
- Department of Clinical Genetics, Erasmus MC, Rotterdam, Netherlands
| | - Renate K Hukema
- Department of Clinical Genetics, Erasmus MC, Rotterdam, Netherlands.,Department of Health Care Studies, Rotterdam University of Applied Sciences, Rotterdam, Netherlands
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Haify SN, Botta-Orfila T, Hukema RK, Tartaglia GG. In silico, in vitro, and in vivo Approaches to Identify Molecular Players in Fragile X Tremor and Ataxia Syndrome. Front Mol Biosci 2020; 7:31. [PMID: 32219099 PMCID: PMC7078329 DOI: 10.3389/fmolb.2020.00031] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 02/11/2020] [Indexed: 12/22/2022] Open
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative monogenetic disorder affecting carriers of premutation (PM) forms of the FMR1 gene, resulting in a progressive development of tremors, ataxia, and neuropsychological problems. This highly disabling disease is quite common in the general population with an estimation of about 20 million PM carriers worldwide. The chances of developing FXTAS increase dramatically with age, with about 45% of male carriers over the age of 50 being affected. Both the gene and pathogenic trigger, a mutant expansion of CGG RNA, causing FXTAS are known. This makes it an interesting disease to develop targeted therapeutic interventions for. Yet, no such interventions are available at this moment. Here we discuss in silico, in vitro, and in vivo approaches and how they have been used to identify the molecular determinants of FXTAS pathology. These approaches have yielded substantial information about FXTAS pathology and, consequently, many markers have emerged to play a key role in understanding the disease mechanism. Integration of the different approaches is expected to provide crucial information about the value of these markers as either therapeutic target or biomarker, essential to monitor therapeutic interventions in the future.
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Affiliation(s)
- Saif N Haify
- Department of Clinical Genetics, Erasmus MC, Rotterdam, Netherlands
| | - Teresa Botta-Orfila
- Biological Fluids Bank of the Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Renate K Hukema
- Department of Clinical Genetics, Erasmus MC, Rotterdam, Netherlands
| | - Gian Gaetano Tartaglia
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.,Department of Biology 'Charles Darwin', Sapienza University of Rome, Rome, Italy.,Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa, Italy.,Universitat Pompeu Fabra (UPF), Barcelona, Spain
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5
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Wenzel HJ, Murray KD, Haify SN, Hunsaker MR, Schwartzer JJ, Kim K, La Spada AR, Sopher BL, Hagerman PJ, Raske C, Severijnen LAWFM, Willemsen R, Hukema RK, Berman RF. Astroglial-targeted expression of the fragile X CGG repeat premutation in mice yields RAN translation, motor deficits and possible evidence for cell-to-cell propagation of FXTAS pathology. Acta Neuropathol Commun 2019; 7:27. [PMID: 30808398 PMCID: PMC6390634 DOI: 10.1186/s40478-019-0677-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 02/10/2019] [Indexed: 01/01/2023] Open
Abstract
The fragile X premutation is a CGG trinucleotide repeat expansion between 55 and 200 repeats in the 5'-untranslated region of the fragile X mental retardation 1 (FMR1) gene. Human carriers of the premutation allele are at risk of developing the late-onset neurodegenerative disorder, fragile X-associated tremor/ataxia syndrome (FXTAS). Characteristic neuropathology associated with FXTAS includes intranuclear inclusions in neurons and astroglia. Previous studies recapitulated these histopathological features in neurons in a knock-in mouse model, but without significant astroglial pathology. To determine the role of astroglia in FXTAS, we generated a transgenic mouse line (Gfa2-CGG99-eGFP) that selectively expresses a 99-CGG repeat expansion linked to an enhanced green fluorescent protein (eGFP) reporter in astroglia throughout the brain, including cerebellar Bergmann glia. Behaviorally these mice displayed impaired motor performance on the ladder-rung test, but paradoxically better performance on the rotarod. Immunocytochemical analysis revealed that CGG99-eGFP co-localized with GFAP and S-100ß, but not with NeuN, Iba1, or MBP, indicating that CGG99-eGFP expression is specific to astroglia. Ubiquitin-positive intranuclear inclusions were found in eGFP-expressing glia throughout the brain. In addition, intracytoplasmic ubiquitin-positive inclusions were found outside the nucleus in distal astrocyte processes. Intriguingly, intranuclear inclusions, in the absence of eGFP mRNA and eGFP fluorescence, were present in neurons of the hypothalamus and neocortex. Furthermore, intranuclear inclusions in both neurons and astrocytes displayed immunofluorescent labeling for the polyglycine peptide FMRpolyG, implicating FMRpolyG in the pathology found in Gfa2-CGG99 mice. Considered together, these results show that Gfa2-CGG99 expression in mice is sufficient to induce key features of FXTAS pathology, including formation of intranuclear inclusions, translation of FMRpolyG, and deficits in motor function.
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Affiliation(s)
- H Jürgen Wenzel
- Department of Neurological Surgery, University of California, Davis, Davis, CA, USA
| | - Karl D Murray
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA
| | - Saif N Haify
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Michael R Hunsaker
- Graduate Program in Neuroscience, University of California, Davis, Davis, CA, USA
| | - Jared J Schwartzer
- Program in Neuroscience and Behavior, Department of Psychology and Education, Mount Holyoke College, South Hadley, MA, USA
| | - Kyoungmi Kim
- Division of Biostatistics, Department of Public Health Sciences, University California Davis, Davis, CA, USA
| | - Albert R La Spada
- Departments of Neurology, Neurobiology, and Cell Biology, and the Duke Center for Neurodegeneration & Neurotherapeutics, Duke University School of Medicine, Durham, NC, USA
| | - Bryce L Sopher
- Department of Neurology, University of Washington School of Medicine, Seattle, WA, USA
| | - Paul J Hagerman
- Department of Biochemistry and Molecular Medicine, University of California, Davis, Davis, CA, USA
| | - Christopher Raske
- Department of Biochemistry and Molecular Medicine, University of California, Davis, Davis, CA, USA
| | | | - Rob Willemsen
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Renate K Hukema
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Robert F Berman
- Department of Neurological Surgery, University of California, Davis, Davis, CA, USA.
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