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Clayton EL, Huggon L, Cousin MA, Mizielinska S. Synaptopathy: presynaptic convergence in frontotemporal dementia and amyotrophic lateral sclerosis. Brain 2024:awae074. [PMID: 38451707 DOI: 10.1093/brain/awae074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 02/02/2024] [Accepted: 02/12/2024] [Indexed: 03/09/2024] Open
Abstract
Frontotemporal dementia and amyotrophic lateral sclerosis are common forms of neurodegenerative disease which share overlapping genetics and pathologies. Crucially, no significantly disease-modifying treatments are available for either disease. Identifying the earliest changes which initiate neuronal dysfunction is important for designing effective intervention therapeutics. The genes mutated in genetic forms of frontotemporal dementia and amyotrophic lateral sclerosis have diverse cellular functions, and multiple disease mechanisms have been proposed for both. Identification of a convergent disease mechanism in frontotemporal dementia and amyotrophic lateral sclerosis would focus research for a targetable pathway which could potentially effectively treat all forms of frontotemporal dementia and amyotrophic lateral sclerosis (both familial and sporadic). Synaptopathies are diseases resulting from physiological dysfunction of synapses, and define the earliest stages in multiple neuronal diseases, with synapse loss a key feature in dementia. At the presynapse, the process of synaptic vesicle recruitment, fusion and recycling is necessary for activity-dependent neurotransmitter release. The unique distal location of the presynaptic terminal means the tight spatio-temporal control of presynaptic homeostasis is dependent on efficient local protein translation and degradation. Recently, numerous publications have shown that mutations associated with frontotemporal dementia and amyotrophic lateral sclerosis present with synaptopathy characterised by presynaptic dysfunction. This review will describe the complex local signalling and membrane trafficking events that occur at the presynapse to facilitate neurotransmission and will summarise recent publications linking frontotemporal dementia/amyotrophic lateral sclerosis genetic mutations to presynaptic function. This evidence indicates that presynaptic synaptopathy is an early and convergent event in frontotemporal dementia and amyotrophic lateral sclerosis and illustrates the need for further research in this area, to identify potential therapeutic targets with the ability to impact this convergent pathomechanism.
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Affiliation(s)
- Emma L Clayton
- UK Dementia Research Institute at King's College London, London, SE5 9RT, UK
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, SE5 9RT, UK
| | - Laura Huggon
- UK Dementia Research Institute at King's College London, London, SE5 9RT, UK
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, SE5 9RT, UK
| | - Michael A Cousin
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
- Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, EH8 9XD, UK
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Sarah Mizielinska
- UK Dementia Research Institute at King's College London, London, SE5 9RT, UK
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, SE5 9RT, UK
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2
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Rothstein JD, Baskerville V, Rapuri S, Mehlhop E, Jafar-Nejad P, Rigo F, Bennett F, Mizielinska S, Isaacs A, Coyne AN. G 2C 4 targeting antisense oligonucleotides potently mitigate TDP-43 dysfunction in human C9orf72 ALS/FTD induced pluripotent stem cell derived neurons. Acta Neuropathol 2023; 147:1. [PMID: 38019311 PMCID: PMC10840905 DOI: 10.1007/s00401-023-02652-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 10/09/2023] [Accepted: 10/26/2023] [Indexed: 11/30/2023]
Abstract
The G4C2 repeat expansion in the C9orf72 gene is the most common genetic cause of Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Many studies suggest that dipeptide repeat proteins produced from this repeat are toxic, yet, the contribution of repeat RNA toxicity is under investigated and even less is known regarding the pathogenicity of antisense repeat RNA. Recently, two clinical trials targeting G4C2 (sense) repeat RNA via antisense oligonucleotide failed despite a robust decrease in sense-encoded dipeptide repeat proteins demonstrating target engagement. Here, in this brief report, we show that G2C4 antisense, but not G4C2 sense, repeat RNA is sufficient to induce TDP-43 dysfunction in induced pluripotent stem cell (iPSC) derived neurons (iPSNs). Unexpectedly, only G2C4, but not G4C2 sense strand targeting, ASOs mitigate deficits in TDP-43 function in authentic C9orf72 ALS/FTD patient iPSNs. Collectively, our data suggest that the G2C4 antisense repeat RNA may be an important therapeutic target and provide insights into a possible explanation for the recent G4C2 ASO clinical trial failure.
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Affiliation(s)
- Jeffrey D Rothstein
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
| | - Victoria Baskerville
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Sampath Rapuri
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Emma Mehlhop
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | | | - Frank Rigo
- Ionis Pharmaceuticals, Carlsbad, CA, 92010, USA
| | | | - Sarah Mizielinska
- UK Dementia Research Institute at King's College London, London, UK
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, Maurice Wohl Clinical Neuroscience Institute, King's College London, London, UK
| | - Adrian Isaacs
- UK Dementia Research Institute at UCL, London, UK
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
- UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, London, UK
| | - Alyssa N Coyne
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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3
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O'Brien N, Mizielinska S. A cryptic clue to neurodegeneration? Science 2023; 379:1090-1091. [PMID: 36927030 DOI: 10.1126/science.adg8501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
Antisense oligonucleotides rescue cryptic RNA splicing and neuron regeneration.
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Affiliation(s)
- Niamh O'Brien
- UK Dementia Research Institute at King's College London, London, UK
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, Camberwell, London, UK
| | - Sarah Mizielinska
- UK Dementia Research Institute at King's College London, London, UK
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, Camberwell, London, UK
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4
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Houghton OH, Mizielinska S, Gomez-Suaga P. The Interplay Between Autophagy and RNA Homeostasis: Implications for Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Front Cell Dev Biol 2022; 10:838402. [PMID: 35573690 PMCID: PMC9096704 DOI: 10.3389/fcell.2022.838402] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [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: 12/17/2021] [Accepted: 04/14/2022] [Indexed: 01/18/2023] Open
Abstract
Amyotrophic lateral sclerosis and frontotemporal dementia are neurodegenerative disorders that lie on a disease spectrum, sharing genetic causes and pathology, and both without effective therapeutics. Two pathways that have been shown to play major roles in disease pathogenesis are autophagy and RNA homeostasis. Intriguingly, there is an increasing body of evidence suggesting a critical interplay between these pathways. Autophagy is a multi-stage process for bulk and selective clearance of malfunctional cellular components, with many layers of regulation. Although the majority of autophagy research focuses on protein degradation, it can also mediate RNA catabolism. ALS/FTD-associated proteins are involved in many stages of autophagy and autophagy-mediated RNA degradation, particularly converging on the clearance of persistent pathological stress granules. In this review, we will summarise the progress in understanding the autophagy-RNA homeostasis interplay and how that knowledge contributes to our understanding of the pathobiology of ALS/FTD.
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Affiliation(s)
- O H Houghton
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom.,UK Dementia Research Institute at King's College London, London, United Kingdom
| | - S Mizielinska
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom.,UK Dementia Research Institute at King's College London, London, United Kingdom
| | - P Gomez-Suaga
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom.,Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, Cáceres, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Instituto Universitario de Investigación Biosanitaria de Extremadura (INUBE), Cáceres, Spain
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5
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Solomon DA, Smikle R, Reid MJ, Mizielinska S. Altered Phase Separation and Cellular Impact in C9orf72-Linked ALS/FTD. Front Cell Neurosci 2021; 15:664151. [PMID: 33967699 PMCID: PMC8096919 DOI: 10.3389/fncel.2021.664151] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [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: 02/04/2021] [Accepted: 03/19/2021] [Indexed: 12/21/2022] Open
Abstract
Since the discovery of the C9orf72 repeat expansion mutation as causative for chromosome 9-linked amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) in 2011, a multitude of cellular pathways have been implicated. However, evidence has also been accumulating for a key mechanism of cellular compartmentalization—phase separation. Liquid-liquid phase separation (LLPS) is fundamental for the formation of membraneless organelles including stress granules, the nucleolus, Cajal bodies, nuclear speckles and the central channel of the nuclear pore. Evidence has now accumulated showing that the formation and function of these membraneless organelles is impaired by both the toxic arginine rich dipeptide repeat proteins (DPRs), translated from the C9orf72 repeat RNA transcript, and the repeat RNA itself. Both the arginine rich DPRs and repeat RNA themselves undergo phase separation and disrupt the physiological phase separation of proteins involved in the formation of these liquid-like organelles. Hence abnormal phase separation may explain a number of pathological cellular phenomena associated with C9orf72-ALS/FTD. In this review article, we will discuss the principles of phase separation, phase separation of the DPRs and repeat RNA themselves and how they perturb LLPS associated with membraneless organelles and the functional consequences of this. We will then discuss how phase separation may impact the major pathological feature of C9orf72-ALS/FTD, TDP-43 proteinopathy, and how LLPS may be targeted therapeutically in disease.
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Affiliation(s)
- Daniel A Solomon
- UK Dementia Research Institute at King's College London, London, United Kingdom.,Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom
| | - Rebekah Smikle
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom
| | - Matthew J Reid
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom
| | - Sarah Mizielinska
- UK Dementia Research Institute at King's College London, London, United Kingdom.,Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom
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6
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Solomon DA, Mitchell JC, Salcher-Konrad MT, Vance CA, Mizielinska S. Review: Modelling the pathology and behaviour of frontotemporal dementia. Neuropathol Appl Neurobiol 2020; 45:58-80. [PMID: 30582188 DOI: 10.1111/nan.12536] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 12/16/2018] [Indexed: 12/11/2022]
Abstract
Frontotemporal dementia (FTD) encompasses a collection of clinically and pathologically diverse neurological disorders. Clinical features of behavioural and language dysfunction are associated with neurodegeneration, predominantly of frontal and temporal cortices. Over the past decade, there have been significant advances in the understanding of the genetic aetiology and neuropathology of FTD which have led to the creation of various disease models to investigate the molecular pathways that contribute to disease pathogenesis. The generation of in vivo models of FTD involves either targeting genes with known disease-causative mutations such as GRN and C9orf72 or genes encoding proteins that form the inclusions that characterize the disease pathologically, such as TDP-43 and FUS. This review provides a comprehensive summary of the different in vivo model systems used to understand pathomechanisms in FTD, with a focus on disease models which reproduce aspects of the wide-ranging behavioural phenotypes seen in people with FTD. We discuss the emerging disease pathways that have emerged from these in vivo models and how this has shaped our understanding of disease mechanisms underpinning FTD. We also discuss the challenges of modelling the complex clinical symptoms shown by people with FTD, the confounding overlap with features of motor neuron disease, and the drive to make models more disease-relevant. In summary, in vivo models can replicate many pathological and behavioural aspects of clinical FTD, but robust and thorough investigations utilizing shared features and variability between disease models will improve the disease-relevance of findings and thus better inform therapeutic development.
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Affiliation(s)
- D A Solomon
- UK Dementia Research Institute, King's College London, London, Camberwell, UK.,Department of Basic & Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, Camberwell, UK
| | - J C Mitchell
- Department of Basic & Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, Camberwell, UK
| | - M-T Salcher-Konrad
- Department of Basic & Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, Camberwell, UK
| | - C A Vance
- Department of Basic & Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, Camberwell, UK
| | - S Mizielinska
- UK Dementia Research Institute, King's College London, London, Camberwell, UK.,Department of Basic & Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, Camberwell, UK
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7
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Moens TG, Mizielinska S, Niccoli T, Mitchell JS, Thoeng A, Ridler CE, Grönke S, Esser J, Heslegrave A, Zetterberg H, Partridge L, Isaacs AM. Sense and antisense RNA are not toxic in Drosophila models of C9orf72-associated ALS/FTD. Acta Neuropathol 2018; 135:445-457. [PMID: 29380049 PMCID: PMC6385858 DOI: 10.1007/s00401-017-1798-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [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: 09/24/2017] [Revised: 12/18/2017] [Accepted: 12/18/2017] [Indexed: 12/14/2022]
Abstract
A GGGGCC hexanucleotide repeat expansion in the C9orf72 gene is the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia. Neurodegeneration may occur via transcription of the repeats into inherently toxic repetitive sense and antisense RNA species, or via repeat-associated non-ATG initiated translation (RANT) of sense and antisense RNA into toxic dipeptide repeat proteins. We have previously demonstrated that regular interspersion of repeat RNA with stop codons prevents RANT (RNA-only models), allowing us to study the role of repeat RNA in isolation. Here we have created novel RNA-only Drosophila models, including the first models of antisense repeat toxicity, and flies expressing extremely large repeats, within the range observed in patients. We generated flies expressing ~ 100 repeat sense or antisense RNA either as part of a processed polyadenylated transcript or intronic sequence. We additionally created Drosophila expressing > 1000 RNA-only repeats in the sense direction. When expressed in adult Drosophila neurons polyadenylated repeat RNA is largely cytoplasmic in localisation, whilst intronic repeat RNA forms intranuclear RNA foci, as does > 1000 repeat RNA, thus allowing us to investigate both nuclear and cytoplasmic RNA toxicity. We confirmed that these RNA foci are capable of sequestering endogenous Drosophila RNA-binding proteins, and that the production of dipeptide proteins (poly-glycine–proline, and poly-glycine–arginine) is suppressed in our models. We find that neither cytoplasmic nor nuclear sense or antisense RNA are toxic when expressed in adult Drosophila neurons, suggesting they have a limited role in disease pathogenesis.
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Affiliation(s)
- Thomas G Moens
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, WC1N 3BG, UK
- Department of Genetics, Evolution and Environment, Institute of Healthy Ageing, University College London, London, WC1E 6BT, UK
| | - Sarah Mizielinska
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, WC1N 3BG, UK
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, SE5 9RT, UK
- UK Dementia Research Institute at King's College London, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, London, SE5 9RT, UK
| | - Teresa Niccoli
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, WC1N 3BG, UK
- Department of Genetics, Evolution and Environment, Institute of Healthy Ageing, University College London, London, WC1E 6BT, UK
| | - Jamie S Mitchell
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Annora Thoeng
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Charlotte E Ridler
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Sebastian Grönke
- Max Planck Institute for Biology of Ageing, 50931, Cologne, Germany
| | - Jacqueline Esser
- Max Planck Institute for Biology of Ageing, 50931, Cologne, Germany
| | - Amanda Heslegrave
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, WC1N 1PJ, UK
- UK Dementia Research Institute at UCL, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Henrik Zetterberg
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, WC1N 1PJ, UK
- Clinical Neurochemistry Laboratory, Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- UK Dementia Research Institute at UCL, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Linda Partridge
- Department of Genetics, Evolution and Environment, Institute of Healthy Ageing, University College London, London, WC1E 6BT, UK.
- Max Planck Institute for Biology of Ageing, 50931, Cologne, Germany.
| | - Adrian M Isaacs
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, WC1N 3BG, UK.
- UK Dementia Research Institute at UCL, UCL Institute of Neurology, London, WC1N 3BG, UK.
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8
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Swinnen B, Bento-Abreu A, Gendron TF, Boeynaems S, Bogaert E, Nuyts R, Timmers M, Scheveneels W, Hersmus N, Wang J, Mizielinska S, Isaacs AM, Petrucelli L, Lemmens R, Van Damme P, Van Den Bosch L, Robberecht W. A zebrafish model for C9orf72 ALS reveals RNA toxicity as a pathogenic mechanism. Acta Neuropathol 2018; 135:427-443. [PMID: 29302778 DOI: 10.1007/s00401-017-1796-5] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 12/13/2017] [Accepted: 12/14/2017] [Indexed: 12/13/2022]
Abstract
The exact mechanism underlying amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) associated with the GGGGCC repeat expansion in C9orf72 is still unclear. Two gain-of-function mechanisms are possible: repeat RNA toxicity and dipeptide repeat protein (DPR) toxicity. We here dissected both possibilities using a zebrafish model for ALS. Expression of two DPRs, glycine-arginine and proline-arginine, induced a motor axonopathy. Similarly, expanded sense and antisense repeat RNA also induced a motor axonopathy and formed mainly cytoplasmic RNA foci. However, DPRs were not detected in these conditions. Moreover, stop codon-interrupted repeat RNA still induced a motor axonopathy and a synergistic role of low levels of DPRs was excluded. Altogether, these results show that repeat RNA toxicity is independent of DPR formation. This RNA toxicity, but not the DPR toxicity, was attenuated by the RNA-binding protein Pur-alpha and the autophagy-related protein p62. Our findings demonstrate that RNA toxicity, independent of DPR toxicity, can contribute to the pathogenesis of C9orf72-associated ALS/FTD.
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9
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Clayton EL, Mancuso R, Nielsen TT, Mizielinska S, Holmes H, Powell N, Norona F, Larsen JO, Milioto C, Wilson KM, Lythgoe MF, Ourselin S, Nielsen JE, Johannsen P, Holm I, Collinge J, Oliver PL, Gomez-Nicola D, Isaacs AM. Early microgliosis precedes neuronal loss and behavioural impairment in mice with a frontotemporal dementia-causing CHMP2B mutation. Hum Mol Genet 2017; 26:873-887. [PMID: 28093491 PMCID: PMC5409096 DOI: 10.1093/hmg/ddx003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 01/03/2017] [Indexed: 01/13/2023] Open
Abstract
Frontotemporal dementia (FTD)-causing mutations in the CHMP2B gene lead to the generation of mutant C-terminally truncated CHMP2B. We report that transgenic mice expressing endogenous levels of mutant CHMP2B developed late-onset brain volume loss associated with frank neuronal loss and FTD-like changes in social behaviour. These data are the first to show neurodegeneration in mice expressing mutant CHMP2B and indicate that our mouse model is able to recapitulate neurodegenerative changes observed in FTD. Neuroinflammation has been increasingly implicated in neurodegeneration, including FTD. Therefore, we investigated neuroinflammation in our CHMP2B mutant mice. We observed very early microglial proliferation that develops into a clear pro-inflammatory phenotype at late stages. Importantly, we also observed a similar inflammatory profile in CHMP2B patient frontal cortex. Aberrant microglial function has also been implicated in FTD caused by GRN, MAPT and C9orf72 mutations. The presence of early microglial changes in our CHMP2B mutant mice indicates neuroinflammation may be a contributing factor to the neurodegeneration observed in FTD.
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Affiliation(s)
- Emma L Clayton
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Renzo Mancuso
- Biological Sciences, University of Southampton, Southampton General Hospital, South Laboratory and Pathology Block, Tremona Road, Southampton SO166YD, UK
| | - Troels Tolstrup Nielsen
- Department of Neurology, Danish Dementia Research Centre, Rigshospitalet, University of Copenhagen, Denmark
| | - Sarah Mizielinska
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Holly Holmes
- Centre for Advanced Biomedical Imaging, Division of Medicine and Institute of Child Health, University College London, 72 Huntley Street, London WC1E 6DD, UK
| | - Nicholas Powell
- Centre for Advanced Biomedical Imaging, Division of Medicine and Institute of Child Health, University College London, 72 Huntley Street, London WC1E 6DD, UK.,Faculty of Health and Medical Sciences, Department of Neuroscience and Pharmacology, Panum Institute, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Frances Norona
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Jytte Overgaard Larsen
- Translational Imaging Group, Centre for Medical Image Computing (CMIC), University College London, UK
| | - Carmelo Milioto
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Katherine M Wilson
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Mark F Lythgoe
- Centre for Advanced Biomedical Imaging, Division of Medicine and Institute of Child Health, University College London, 72 Huntley Street, London WC1E 6DD, UK
| | - Sebastian Ourselin
- Faculty of Health and Medical Sciences, Department of Neuroscience and Pharmacology, Panum Institute, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Jörgen E Nielsen
- Department of Neurology, Danish Dementia Research Centre, Rigshospitalet, University of Copenhagen, Denmark.,Section of Neurogenetics, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Peter Johannsen
- Department of Neurology, Danish Dementia Research Centre, Rigshospitalet, University of Copenhagen, Denmark
| | - Ida Holm
- Laboratory for Experimental Neuropathology, Department of Pathology, Randers Hospital, DK-8930 Randers NØ, Denmark.,Institute of Clinical Medicine, Aarhus University, DK-8000 Aarhus C, Denmark
| | - John Collinge
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK.,MRC Prion Unit, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | | | - Peter L Oliver
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, UK
| | - Diego Gomez-Nicola
- Biological Sciences, University of Southampton, Southampton General Hospital, South Laboratory and Pathology Block, Tremona Road, Southampton SO166YD, UK
| | - Adrian M Isaacs
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
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10
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Mizielinska S, Ridler CE, Balendra R, Thoeng A, Woodling NS, Grässer FA, Plagnol V, Lashley T, Partridge L, Isaacs AM. Bidirectional nucleolar dysfunction in C9orf72 frontotemporal lobar degeneration. Acta Neuropathol Commun 2017; 5:29. [PMID: 28420437 PMCID: PMC5395972 DOI: 10.1186/s40478-017-0432-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 04/06/2017] [Indexed: 01/08/2023] Open
Abstract
An intronic GGGGCC expansion in C9orf72 is the most common known cause of both frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). The repeat expansion leads to the generation of sense and antisense repeat RNA aggregates and dipeptide repeat (DPR) proteins, generated by repeat-associated non-ATG translation. The arginine-rich DPR proteins poly(glycine-arginine or GR) and poly(proline-arginine or PR) are potently neurotoxic and can localise to the nucleolus when expressed in cells, resulting in enlarged nucleoli with disrupted functionality. Furthermore, GGGGCC repeat RNA can bind nucleolar proteins in vitro. However, the relevance of nucleolar stress is unclear, as the arginine-rich DPR proteins do not localise to the nucleolus in C9orf72-associated FTLD/ALS (C9FTLD/ALS) patient brain. We measured nucleolar size in C9FTLD frontal cortex neurons using a three-dimensional, volumetric approach. Intriguingly, we found that C9FTLD brain exhibited bidirectional nucleolar stress. C9FTLD neuronal nucleoli were significantly smaller than control neuronal nucleoli. However, within C9FTLD brains, neurons containing poly(GR) inclusions had significantly larger nucleolar volumes than neurons without poly(GR) inclusions. In addition, expression of poly(GR) in adult Drosophila neurons led to significantly enlarged nucleoli. A small but significant increase in nucleolar volume was also observed in C9FTLD frontal cortex neurons containing GGGGCC repeat-containing RNA foci. These data show that nucleolar abnormalities are a consistent feature of C9FTLD brain, but that diverse pathomechanisms are at play, involving both DPR protein and repeat RNA toxicity.
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Affiliation(s)
- Sarah Mizielinska
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London WC1N 3BG, UK
| | - Adrian M Isaacs
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London WC1N 3BG, UK.
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12
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Clayton EL, Mizielinska S, Edgar JR, Nielsen TT, Marshall S, Norona FE, Robbins M, Damirji H, Holm IE, Johannsen P, Nielsen JE, Asante EA, Collinge J, Isaacs AM. Frontotemporal dementia caused by CHMP2B mutation is characterised by neuronal lysosomal storage pathology. Acta Neuropathol 2015; 130:511-23. [PMID: 26358247 PMCID: PMC4575387 DOI: 10.1007/s00401-015-1475-3] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [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: 07/07/2015] [Revised: 09/01/2015] [Accepted: 09/02/2015] [Indexed: 12/13/2022]
Abstract
Mutations in the charged multivesicular body protein 2B (CHMP2B) cause frontotemporal dementia (FTD). We report that mice which express FTD-causative mutant CHMP2B at physiological levels develop a novel lysosomal storage pathology characterised by large neuronal autofluorescent aggregates. The aggregates are an early and progressive pathology that occur at 3 months of age and increase in both size and number over time. These autofluorescent aggregates are not observed in mice expressing wild-type CHMP2B, or in non-transgenic controls, indicating that they are a specific pathology caused by mutant CHMP2B. Ultrastructural analysis and immuno- gold labelling confirmed that they are derived from the endolysosomal system. Consistent with these findings, CHMP2B mutation patient brains contain morphologically similar autofluorescent aggregates. These aggregates occur significantly more frequently in human CHMP2B mutation brain than in neurodegenerative disease or age-matched control brains. These data suggest that lysosomal storage pathology is the major neuronal pathology in FTD caused by CHMP2B mutation. Recent evidence suggests that two other genes associated with FTD, GRN and TMEM106B are important for lysosomal function. Our identification of lysosomal storage pathology in FTD caused by CHMP2B mutation now provides evidence that endolysosomal dysfunction is a major degenerative pathway in FTD.
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Affiliation(s)
- Emma L Clayton
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Sarah Mizielinska
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - James R Edgar
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
| | - Troels Tolstrup Nielsen
- Neurogenetics Research Laboratory, Department of Neurology, Danish Dementia Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Sarah Marshall
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Frances E Norona
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Miranda Robbins
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Hana Damirji
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Ida E Holm
- Laboratory for Experimental Neuropathology, Department of Pathology, Randers Hospital, 8930, Randers NØ, Denmark
- Institute of Clinical Medicine, Aarhus University, 8000, Aarhus C, Denmark
| | - Peter Johannsen
- Memory Clinic, Department of Neurology, Danish Dementia Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen E Nielsen
- Neurogenetics Research Laboratory, Department of Neurology, Danish Dementia Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- Memory Clinic, Department of Neurology, Danish Dementia Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- Department of Cellular and Molecular Medicine, Section of Neurogenetics, The Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Emmanuel A Asante
- MRC Prion Unit, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - John Collinge
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
- MRC Prion Unit, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Adrian M Isaacs
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK.
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13
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Fratta P, Polke JM, Newcombe J, Mizielinska S, Lashley T, Poulter M, Beck J, Preza E, Devoy A, Sidle K, Howard R, Malaspina A, Orrell RW, Clarke J, Lu CH, Mok K, Collins T, Shoaii M, Nanji T, Wray S, Adamson G, Pittman A, Renton AE, Traynor BJ, Sweeney MG, Revesz T, Houlden H, Mead S, Isaacs AM, Fisher EMC. Screening a UK amyotrophic lateral sclerosis cohort provides evidence of multiple origins of the C9orf72 expansion. Neurobiol Aging 2015; 36:546.e1-7. [PMID: 25179228 PMCID: PMC4270445 DOI: 10.1016/j.neurobiolaging.2014.07.037] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 07/27/2014] [Indexed: 12/13/2022]
Abstract
An expanded hexanucleotide repeat in the C9orf72 gene is the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia (C9ALS/FTD). Although 0-30 hexanucleotide repeats are present in the general population, expansions >500 repeats are associated with C9ALS/FTD. Large C9ALS/FTD expansions share a common haplotype and whether these expansions derive from a single founder or occur more frequently on a predisposing haplotype is yet to be determined and is relevant to disease pathomechanisms. Furthermore, although cases carrying 50-200 repeats have been described, their role and the pathogenic threshold of the expansions remain to be identified and carry importance for diagnostics and genetic counseling. We present clinical and genetic data from a UK ALS cohort and report the detailed molecular study of an atypical somatically unstable expansion of 90 repeats. Our results across different tissues provide evidence for the pathogenicity of this repeat number by showing they can somatically expand in the central nervous system to the well characterized pathogenic range. Our results support the occurrence of multiple expansion events for C9ALS/FTD.
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Affiliation(s)
- Pietro Fratta
- Department of Neurodegenerative Disease, University College London, Queen Square, London, UK; MRC Centre for Neuromuscular Diseases, University College London, Queen Square, London, UK.
| | | | - Jia Newcombe
- NeuroResource, Institute of Neurology, University College London, Queen Square, London, UK
| | - Sarah Mizielinska
- Department of Neurodegenerative Disease, University College London, Queen Square, London, UK
| | - Tammaryn Lashley
- Queen Square Brain Bank for Neurological Disorders, University College London, Queen Square, London, UK
| | - Mark Poulter
- Department of Neurodegenerative Disease, University College London, Queen Square, London, UK; MRC Prion Unit, University College London, Queen Square, London, UK
| | - Jon Beck
- Department of Neurodegenerative Disease, University College London, Queen Square, London, UK; MRC Prion Unit, University College London, Queen Square, London, UK
| | - Elisavet Preza
- Department of Molecular Neuroscience, University College London, Queen Square, London, UK
| | - Anny Devoy
- Department of Neurodegenerative Disease, University College London, Queen Square, London, UK
| | - Katie Sidle
- Department of Molecular Neuroscience, University College London, Queen Square, London, UK; National Hospital for Neurology and Neurosurgery, Queen Square, London, UK
| | - Robin Howard
- National Hospital for Neurology and Neurosurgery, Queen Square, London, UK
| | - Andrea Malaspina
- National Hospital for Neurology and Neurosurgery, Queen Square, London, UK; Centre for Neuroscience & Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, UK
| | - Richard W Orrell
- MRC Centre for Neuromuscular Diseases, University College London, Queen Square, London, UK; Department of Molecular Neuroscience, University College London, Queen Square, London, UK; National Hospital for Neurology and Neurosurgery, Queen Square, London, UK
| | - Jan Clarke
- National Hospital for Neurology and Neurosurgery, Queen Square, London, UK
| | - Ching-Hua Lu
- Centre for Neuroscience & Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, UK; Sobell Department of Motor Neuroscience and Movement Disorders, University College London, Queen Square, London, UK
| | - Kin Mok
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London, Queen Square, London, UK
| | - Toby Collins
- Department of Neurodegenerative Disease, University College London, Queen Square, London, UK
| | - Maryam Shoaii
- Department of Molecular Neuroscience, University College London, Queen Square, London, UK
| | - Tina Nanji
- Neurogenetics Unit, Queen Square, London, UK
| | - Selina Wray
- Department of Molecular Neuroscience, University College London, Queen Square, London, UK
| | - Gary Adamson
- Department of Neurodegenerative Disease, University College London, Queen Square, London, UK; MRC Prion Unit, University College London, Queen Square, London, UK
| | - Alan Pittman
- Department of Molecular Neuroscience, University College London, Queen Square, London, UK
| | - Alan E Renton
- Neuromuscular Diseases Research Section, Laboratory of Neurogenetics, National Institutes of Health, National Institute on Aging, Bethesda, MD, USA
| | - Bryan J Traynor
- Neuromuscular Diseases Research Section, Laboratory of Neurogenetics, National Institutes of Health, National Institute on Aging, Bethesda, MD, USA
| | | | - Tamas Revesz
- Queen Square Brain Bank for Neurological Disorders, University College London, Queen Square, London, UK
| | - Henry Houlden
- Neurogenetics Unit, Queen Square, London, UK; Department of Molecular Neuroscience, University College London, Queen Square, London, UK
| | - Simon Mead
- Department of Neurodegenerative Disease, University College London, Queen Square, London, UK
| | - Adrian M Isaacs
- Department of Neurodegenerative Disease, University College London, Queen Square, London, UK
| | - Elizabeth M C Fisher
- Department of Neurodegenerative Disease, University College London, Queen Square, London, UK; MRC Centre for Neuromuscular Diseases, University College London, Queen Square, London, UK.
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14
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Mizielinska S, Grönke S, Niccoli T, Ridler CE, Clayton EL, Devoy A, Moens T, Norona FE, Woollacott IOC, Pietrzyk J, Cleverley K, Nicoll AJ, Pickering-Brown S, Dols J, Cabecinha M, Hendrich O, Fratta P, Fisher EMC, Partridge L, Isaacs AM. C9orf72 repeat expansions cause neurodegeneration in Drosophila through arginine-rich proteins. Science 2014; 345:1192-1194. [PMID: 25103406 DOI: 10.1126/science.1256800] [Citation(s) in RCA: 521] [Impact Index Per Article: 52.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
An expanded GGGGCC repeat in C9orf72 is the most common genetic cause of frontotemporal dementia and amyotrophic lateral sclerosis. A fundamental question is whether toxicity is driven by the repeat RNA itself and/or by dipeptide repeat proteins generated by repeat-associated, non-ATG translation. To address this question, we developed in vitro and in vivo models to dissect repeat RNA and dipeptide repeat protein toxicity. Expression of pure repeats, but not stop codon-interrupted "RNA-only" repeats in Drosophila caused adult-onset neurodegeneration. Thus, expanded repeats promoted neurodegeneration through dipeptide repeat proteins. Expression of individual dipeptide repeat proteins with a non-GGGGCC RNA sequence revealed that both poly-(glycine-arginine) and poly-(proline-arginine) proteins caused neurodegeneration. These findings are consistent with a dual toxicity mechanism, whereby both arginine-rich proteins and repeat RNA contribute to C9orf72-mediated neurodegeneration.
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Affiliation(s)
- Sarah Mizielinska
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Sebastian Grönke
- Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9b, 50931 Cologne, Germany
| | - Teresa Niccoli
- Department of Genetics, Evolution and Environment, Institute of Healthy Ageing, UCL, Darwin Building, Gower Street, London WC1E 6BT, UK
| | - Charlotte E Ridler
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Emma L Clayton
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Anny Devoy
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Thomas Moens
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK.,Department of Genetics, Evolution and Environment, Institute of Healthy Ageing, UCL, Darwin Building, Gower Street, London WC1E 6BT, UK
| | - Frances E Norona
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Ione O C Woollacott
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Julian Pietrzyk
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Karen Cleverley
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Andrew J Nicoll
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK.,MRC Prion Unit, UCL Institute of Neurology, London WC1N 3BG, UK
| | - Stuart Pickering-Brown
- Institute of Brain, Behaviour and Mental Health, Faculty of Human and Medical Sciences, University of Manchester, AV Hill Building, Oxford Road, Manchester, M13 9PT, UK
| | - Jacqueline Dols
- Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9b, 50931 Cologne, Germany
| | - Melissa Cabecinha
- Department of Genetics, Evolution and Environment, Institute of Healthy Ageing, UCL, Darwin Building, Gower Street, London WC1E 6BT, UK
| | - Oliver Hendrich
- Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9b, 50931 Cologne, Germany
| | - Pietro Fratta
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK.,MRC Centre for Neuromuscular Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Elizabeth M C Fisher
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK.,MRC Centre for Neuromuscular Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Linda Partridge
- Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9b, 50931 Cologne, Germany.,Department of Genetics, Evolution and Environment, Institute of Healthy Ageing, UCL, Darwin Building, Gower Street, London WC1E 6BT, UK
| | - Adrian M Isaacs
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
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15
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Mizielinska S, Lashley T, Norona FE, Clayton EL, Ridler CE, Fratta P, Isaacs AM. C9orf72 frontotemporal lobar degeneration is characterised by frequent neuronal sense and antisense RNA foci. Acta Neuropathol 2013; 126:845-57. [PMID: 24170096 PMCID: PMC3830745 DOI: 10.1007/s00401-013-1200-z] [Citation(s) in RCA: 246] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 10/16/2013] [Accepted: 10/19/2013] [Indexed: 12/11/2022]
Abstract
An expanded GGGGCC repeat in a non-coding region of the C9orf72 gene is a common cause of frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis. Non-coding repeat expansions may cause disease by reducing the expression level of the gene they reside in, by producing toxic aggregates of repeat RNA termed RNA foci, or by producing toxic proteins generated by repeat-associated non-ATG translation. We present the first definitive report of C9orf72 repeat sense and antisense RNA foci using a series of C9FTLD cases, and neurodegenerative disease and normal controls. A sensitive and specific fluorescence in situ hybridisation protocol was combined with protein immunostaining to show that both sense and antisense foci were frequent, specific to C9FTLD, and present in neurons of the frontal cortex, hippocampus and cerebellum. High-resolution imaging also allowed accurate analyses of foci number and subcellular localisation. RNA foci were most abundant in the frontal cortex, where 51 % of neurons contained foci. RNA foci also occurred in astrocytes, microglia and oligodendrocytes but to a lesser degree than in neurons. RNA foci were observed in both TDP-43- and p62-inclusion bearing neurons, but not at a greater frequency than expected by chance. RNA foci abundance in the frontal cortex showed a significant inverse correlation with age at onset of disease. These data establish that sense and antisense C9orf72 repeat RNA foci are a consistent and specific feature of C9FTLD, providing new insight into the pathogenesis of C9FTLD.
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Affiliation(s)
- Sarah Mizielinska
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Tammaryn Lashley
- Department of Molecular Neuroscience, Queen Square Brain Bank, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Frances E. Norona
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Emma L. Clayton
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Charlotte E. Ridler
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Pietro Fratta
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
- MRC Centre for Neuromuscular Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Adrian M. Isaacs
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
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16
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Fratta P, Poulter M, Lashley T, Rohrer JD, Polke JM, Beck J, Ryan N, Hensman D, Mizielinska S, Waite AJ, Lai MC, Gendron TF, Petrucelli L, Fisher EMC, Revesz T, Warren JD, Collinge J, Isaacs AM, Mead S. Homozygosity for the C9orf72 GGGGCC repeat expansion in frontotemporal dementia. Acta Neuropathol 2013; 126:401-9. [PMID: 23818065 PMCID: PMC3753468 DOI: 10.1007/s00401-013-1147-0] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [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: 05/11/2013] [Revised: 06/16/2013] [Accepted: 06/18/2013] [Indexed: 12/12/2022]
Abstract
An expanded hexanucleotide repeat in the C9orf72 gene is the most common genetic cause of frontotemporal dementia and amyotrophic lateral sclerosis (c9FTD/ALS). We now report the first description of a homozygous patient and compare it to a series of heterozygous cases. The patient developed early-onset frontotemporal dementia without additional features. Neuropathological analysis showed c9FTD/ALS characteristics, with abundant p62-positive inclusions in the frontal and temporal cortices, hippocampus and cerebellum, as well as less abundant TDP-43-positive inclusions. Overall, the clinical and pathological features were severe, but did not fall outside the usual disease spectrum. Quantification of C9orf72 transcript levels in post-mortem brain demonstrated expression of all known C9orf72 transcript variants, but at a reduced level. The pathogenic mechanisms by which the hexanucleotide repeat expansion causes disease are unclear and both gain- and loss-of-function mechanisms may play a role. Our data support a gain-of-function mechanism as pure homozygous loss of function would be expected to lead to a more severe, or completely different clinical phenotype to the one described here, which falls within the usual range. Our findings have implications for genetic counselling, highlighting the need to use genetic tests that distinguish C9orf72 homozygosity.
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Affiliation(s)
- Pietro Fratta
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Mark Poulter
- MRC Prion Unit, Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Tammaryn Lashley
- Queen Square Brain Bank, Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Jonathan D. Rohrer
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - James M. Polke
- Neurogenetics Unit, National Hospital for Neurology and Neurosurgery, Queen Square, London, WC1N 3BG UK
| | - Jon Beck
- MRC Prion Unit, Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Natalie Ryan
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Davina Hensman
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Sarah Mizielinska
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Adrian J. Waite
- Institute of Psychological Medicine and Clinical Neurosciences, MRC Centre for Neuropsychiatric Genetics and Genomics, School of Medicine, Cardiff University, Cardiff, CF14 4XN UK
| | - Mang-Ching Lai
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Tania F. Gendron
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, FL 32224 USA
| | - Leonard Petrucelli
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, FL 32224 USA
| | - Elizabeth M. C. Fisher
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Tamas Revesz
- Queen Square Brain Bank, Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Jason D. Warren
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - John Collinge
- MRC Prion Unit, Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Adrian M. Isaacs
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Simon Mead
- MRC Prion Unit, Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
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17
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Nielsen TT, Mizielinska S, Hasholt L, Isaacs AM, Nielsen JE. Reversal of pathology in CHMP2B-mediated frontotemporal dementia patient cells using RNA interference. J Gene Med 2013; 14:521-9. [PMID: 22786763 DOI: 10.1002/jgm.2649] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Frontotemporal dementia is the second most common form of young-onset dementia after Alzheimer's disease, and several genetic forms of frontotemporal dementia are known. A rare genetic variant is caused by a point mutation in the CHMP2B gene. CHMP2B is a component of the ESCRT-III complex, which is involved in endosomal trafficking of proteins targeted for degradation in lysosomes. Mutations in CHMP2B result in abnormal endosomal structures in patient fibroblasts and patient brains, probably through a gain-of-function mechanism, suggesting that the endosomal pathway plays a central role in the pathogenesis of the disease. METHODS In the present study, we used lentiviral vectors to efficiently knockdown CHMP2B by delivering microRNA embedded small hairpin RNAs. RESULTS We show that CHMP2B can be efficiently knocked down in patient fibroblasts using an RNA interference approach and that the knockdown causes reversal of the abnormal endosomal phenotype observed in patient fibroblasts. CONCLUSIONS This is the first description of a treatment that reverses the cellular pathology caused by mutant CHMP2B and suggests that RNA interference might be a feasible therapeutic strategy. Furthermore, it provides the first proof of a direct link between the disease-causing mutation and the cellular phenotype in cells originating from CHMP2B mutation patients.
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Affiliation(s)
- Troels Tolstrup Nielsen
- Danish Dementia Research Centre, Department of Neurology, Rigshospitalet, Copenhagen University Hospital, Denmark.
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18
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Fratta P, Mizielinska S, Nicoll AJ, Zloh M, Fisher EMC, Parkinson G, Isaacs AM. C9orf72 hexanucleotide repeat associated with amyotrophic lateral sclerosis and frontotemporal dementia forms RNA G-quadruplexes. Sci Rep 2012; 2:1016. [PMID: 23264878 PMCID: PMC3527825 DOI: 10.1038/srep01016] [Citation(s) in RCA: 240] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 12/07/2012] [Indexed: 12/14/2022] Open
Abstract
Large expansions of a non-coding GGGGCC-repeat in the first intron of the C9orf72 gene are a common cause of both amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). G-rich sequences have a propensity for forming highly stable quadruplex structures in both RNA and DNA termed G-quadruplexes. G-quadruplexes have been shown to be involved in a range of processes including telomere stability and RNA transcription, splicing, translation and transport. Here we show using NMR and CD spectroscopy that the C9orf72 hexanucleotide expansion can form a stable G-quadruplex, which has profound implications for disease mechanism in ALS and FTD.
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Affiliation(s)
- Pietro Fratta
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
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Ghazi-Noori S, Froud KE, Mizielinska S, Powell C, Smidak M, Fernandez de Marco M, O'Malley C, Farmer M, Parkinson N, Fisher EMC, Asante EA, Brandner S, Collinge J, Isaacs AM. Progressive neuronal inclusion formation and axonal degeneration in CHMP2B mutant transgenic mice. ACTA ACUST UNITED AC 2012; 135:819-32. [PMID: 22366797 DOI: 10.1093/brain/aws006] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mutations in the charged multivesicular body protein 2B (CHMP2B) gene cause frontotemporal lobar degeneration. The mutations lead to C-terminal truncation of the CHMP2B protein. We generated Chmp2b knockout mice and transgenic mice expressing either wild-type or C-terminally truncated mutant CHMP2B. The transgenic CHMP2B mutant mice have decreased survival and show progressive neurodegenerative changes including gliosis and increasing accumulation of p62- and ubiquitin-positive inclusions. The inclusions are negative for the TAR DNA binding protein 43 and fused in sarcoma proteins, mimicking the inclusions observed in patients with CHMP2B mutation. Mice transgenic for mutant CHMP2B also develop an early and progressive axonopathy characterized by numerous amyloid precursor protein-positive axonal swellings, implicating altered axonal function in disease pathogenesis. These findings were not observed in Chmp2b knockout mice or in transgenic mice expressing wild-type CHMP2B, indicating that CHMP2B mutations induce degenerative changes through a gain of function mechanism. These data describe the first mouse model of dementia caused by CHMP2B mutation and provide new insights into the mechanisms of CHMP2B-induced neurodegeneration.
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O’Malley D, MacDonald N, Mizielinska S, Connolly CN, Irving AJ, Harvey J. Leptin promotes rapid dynamic changes in hippocampal dendritic morphology. Mol Cell Neurosci 2007; 35:559-72. [PMID: 17618127 PMCID: PMC1995039 DOI: 10.1016/j.mcn.2007.05.001] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2006] [Revised: 04/24/2007] [Accepted: 05/01/2007] [Indexed: 01/23/2023] Open
Abstract
Recent studies have implicated the hormone leptin in synaptic plasticity associated with neuronal development and learning and memory. Indeed, leptin facilitates hippocampal long-term potentiation and leptin-insensitive rodents display impaired hippocampal synaptic plasticity suggesting a role for endogenous leptin. Structural changes are also thought to underlie activity-dependent synaptic plasticity and this may be regulated by specific growth factors. As leptin is reported to have neurotrophic actions, we have examined the effects of leptin on the morphology and filopodial outgrowth in hippocampal neurons. Here, we demonstrate that leptin rapidly enhances the motility and density of dendritic filopodia and subsequently increases the density of hippocampal synapses. This process is dependent on the synaptic activation of NR2A-containing NMDA receptors and is mediated by the MAPK (ERK) signaling pathway. As dendritic morphogenesis is associated with activity-dependent changes in synaptic strength, the rapid structural remodeling of dendrites by leptin has important implications for its role in regulating hippocampal synaptic plasticity and neuronal development.
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Abstract
Maintaining the correct balance in neuronal activation is of paramount importance to normal brain function. Imbalances due to changes in excitation or inhibition can lead to a variety of disorders ranging from the clinically extreme (e.g. epilepsy) to the more subtle (e.g. anxiety). In the brain, the most common inhibitory synapses are regulated by GABAA (γ-aminobutyric acid type A) receptors, a role commensurate with their importance as therapeutic targets. Remarkably, we still know relatively little about GABAA receptor biogenesis. Receptors are constructed as pentameric ion channels, with α and β subunits being the minimal requirement, and the incorporation of a γ subunit being necessary for benzodiazepine modulation and synaptic targeting. Insights have been provided by the discovery of several specific assembly signals within different GABAA receptor subunits. Moreover, a number of recent studies on GABAA receptor mutations associated with epilepsy have further enhanced our understanding of GABAA receptor biogenesis, structure and function.
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Affiliation(s)
- S Mizielinska
- Neuroscience Institute, Ninewells Medical School, University of Dundee, Dundee DD1 9SY, UK
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