51
|
Malik I, Tseng Y, Wright SE, Zheng K, Ramaiyer P, Green KM, Todd PK. SRSF protein kinase 1 modulates RAN translation and suppresses CGG repeat toxicity. EMBO Mol Med 2021; 13:e14163. [PMID: 34542927 PMCID: PMC8573603 DOI: 10.15252/emmm.202114163] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 08/28/2021] [Accepted: 08/30/2021] [Indexed: 11/20/2022] Open
Abstract
Transcribed CGG repeat expansions cause neurodegeneration in Fragile X-associated tremor/ataxia syndrome (FXTAS). CGG repeat RNAs sequester RNA-binding proteins (RBPs) into nuclear foci and undergo repeat-associated non-AUG (RAN) translation into toxic peptides. To identify proteins involved in these processes, we employed a CGG repeat RNA-tagging system to capture repeat-associated RBPs by mass spectrometry in mammalian cells. We identified several SR (serine/arginine-rich) proteins that interact selectively with CGG repeats basally and under cellular stress. These proteins modify toxicity in a Drosophila model of FXTAS. Pharmacologic inhibition of serine/arginine protein kinases (SRPKs), which alter SRSF protein phosphorylation, localization, and activity, directly inhibits RAN translation of CGG and GGGGCC repeats (associated with C9orf72 ALS/FTD) and triggers repeat RNA retention in the nucleus. Lowering SRPK expression suppressed toxicity in both FXTAS and C9orf72 ALS/FTD model flies, and SRPK inhibitors suppressed CGG repeat toxicity in rodent neurons. Together, these findings demonstrate roles for CGG repeat RNA binding proteins in RAN translation and repeat toxicity and support further evaluation of SRPK inhibitors in modulating RAN translation associated with repeat expansion disorders.
Collapse
Affiliation(s)
- Indranil Malik
- Department of NeurologyUniversity of MichiganAnn ArborMIUSA
| | - Yi‐Ju Tseng
- Department of NeurologyUniversity of MichiganAnn ArborMIUSA
- Cellular and Molecular Biology Graduate ProgramUniversity of MichiganAnn ArborMIUSA
| | - Shannon E Wright
- Department of NeurologyUniversity of MichiganAnn ArborMIUSA
- Neuroscience Graduate ProgramUniversity of MichiganAnn ArborMIUSA
| | - Kristina Zheng
- Department of NeurologyUniversity of MichiganAnn ArborMIUSA
| | | | - Katelyn M Green
- Department of NeurologyUniversity of MichiganAnn ArborMIUSA
- Cellular and Molecular Biology Graduate ProgramUniversity of MichiganAnn ArborMIUSA
| | - Peter K Todd
- Department of NeurologyUniversity of MichiganAnn ArborMIUSA
- Ann Arbor Veterans Administration HealthcareAnn ArborMIUSA
| |
Collapse
|
52
|
Montagnese F. Current Treatment Options for Patients with Myotonic Dystrophy Type 2. Curr Treat Options Neurol 2021. [DOI: 10.1007/s11940-021-00686-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Abstract
Purpose of the review
Myotonic dystrophy types 1 and 2 are frequent forms of muscular dystrophies in adulthood. Their clinical differences need to be taken into account for the most appropriate treatment of patients. The aim of this article is to provide an overview on the current and upcoming therapeutic options for patients with myotonic dystrophy type 2 (DM2).
Recent findings
At the moment, no disease-modifying therapies are available for DM2; next-generation therapies may however be available in the near future. In the meanwhile, the symptomatic management of patients has greatly improved, thank to the production of consensus-based standards of care and the growing evidence of efficacy of anti-myotonic drugs, promising employment of cannabinoids for symptom’s relief, regular monitoring, and early detection of treatable extra-muscular manifestations.
Summary
The treatment of DM2 is currently symptomatic and relies on the coordinated intervention of a multidisciplinary team. It remains to be determined whether upcoming causal therapies for myotonic dystrophy type 1 will be applicable also in DM2.
Collapse
|
53
|
Coni S, Falconio FA, Marzullo M, Munafò M, Zuliani B, Mosti F, Fatica A, Ianniello Z, Bordone R, Macone A, Agostinelli E, Perna A, Matkovic T, Sigrist S, Silvestri G, Canettieri G, Ciapponi L. Translational control of polyamine metabolism by CNBP is required for Drosophila locomotor function. eLife 2021; 10:69269. [PMID: 34517941 PMCID: PMC8439652 DOI: 10.7554/elife.69269] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 08/08/2021] [Indexed: 01/19/2023] Open
Abstract
Microsatellite expansions of CCTG repeats in the cellular nucleic acid-binding protein (CNBP) gene leads to accumulation of toxic RNA and have been associated with myotonic dystrophy type 2 (DM2). However, it is still unclear whether the dystrophic phenotype is also linked to CNBP decrease, a conserved CCHC-type zinc finger RNA-binding protein that regulates translation and is required for mammalian development. Here, we show that depletion of Drosophila CNBP in muscles causes ageing-dependent locomotor defects that are correlated with impaired polyamine metabolism. We demonstrate that the levels of ornithine decarboxylase (ODC) and polyamines are significantly reduced upon dCNBP depletion. Of note, we show a reduction of the CNBP-polyamine axis in muscles from DM2 patients. Mechanistically, we provide evidence that dCNBP controls polyamine metabolism through binding dOdc mRNA and regulating its translation. Remarkably, the locomotor defect of dCNBP-deficient flies is rescued by either polyamine supplementation or dOdc1 overexpression. We suggest that this dCNBP function is evolutionarily conserved in vertebrates with relevant implications for CNBP-related pathophysiological conditions.
Collapse
Affiliation(s)
- Sonia Coni
- Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Federica A Falconio
- Department of Biology and Biotechnologies, Sapienza University of Rome, Rome, Italy.,Department of Life Sciences Imperial College London South Kensington campus, London, United Kingdom
| | - Marta Marzullo
- Department of Biology and Biotechnologies, Sapienza University of Rome, Rome, Italy.,IBPM CNR c/o Department of Biology and Biotechnology, Sapienza University of Rome, Rome, Italy
| | - Marzia Munafò
- European Molecular Biology Laboratory (EMBL) Epigenetics & Neurobiology Unit, Campus Adriano Buzzati-Traverso, Monterotond, Italy
| | - Benedetta Zuliani
- Department of Biology and Biotechnologies, Sapienza University of Rome, Rome, Italy
| | - Federica Mosti
- Department of Biology and Biotechnologies, Sapienza University of Rome, Rome, Italy.,Department of Neurobiology, Duke University Medical Center, Durham, United States
| | - Alessandro Fatica
- Department of Biology and Biotechnologies, Sapienza University of Rome, Rome, Italy
| | - Zaira Ianniello
- Department of Biology and Biotechnologies, Sapienza University of Rome, Rome, Italy
| | - Rosa Bordone
- Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Alberto Macone
- Department of Biochemical Sciences, Sapienza University of Rome, Rome, Italy
| | - Enzo Agostinelli
- Department of Sensory Organs, Sapienza University of Rome, Policlinico Umberto I, Rome, Italy.,International Polyamines Foundation 'ETS-ONLUS', Rome, Italy
| | - Alessia Perna
- Department of Neuroscience, Fondazione Policlinico Gemelli IRCCS, University Cattolica del S. Cuore, Roma, Italy
| | - Tanja Matkovic
- Freie Universität Berlin, Institute for Biology and Genetics, Berlin, Germany
| | - Stephan Sigrist
- Freie Universität Berlin, Institute for Biology and Genetics, Berlin, Germany
| | - Gabriella Silvestri
- Department of Neuroscience, Fondazione Policlinico Gemelli IRCCS, University Cattolica del S. Cuore, Roma, Italy.,Department of Scienze dell'Invecchiamento, Neurologiche, Ortopediche e della testa-Collo; UOC Neurologia, Fondazione Policlinico Universitario 'A. Gemelli' IRCCS, Rome, Italy
| | - Gianluca Canettieri
- Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy.,International Polyamines Foundation 'ETS-ONLUS', Rome, Italy.,Pasteur Institute, Fondazione Cenci-Bolognetti, Rome, Italy
| | - Laura Ciapponi
- Department of Biology and Biotechnologies, Sapienza University of Rome, Rome, Italy
| |
Collapse
|
54
|
Malik I, Kelley CP, Wang ET, Todd PK. Molecular mechanisms underlying nucleotide repeat expansion disorders. Nat Rev Mol Cell Biol 2021; 22:589-607. [PMID: 34140671 PMCID: PMC9612635 DOI: 10.1038/s41580-021-00382-6] [Citation(s) in RCA: 203] [Impact Index Per Article: 50.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/30/2021] [Indexed: 02/05/2023]
Abstract
The human genome contains over one million short tandem repeats. Expansion of a subset of these repeat tracts underlies over fifty human disorders, including common genetic causes of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (C9orf72), polyglutamine-associated ataxias and Huntington disease, myotonic dystrophy, and intellectual disability disorders such as Fragile X syndrome. In this Review, we discuss the four major mechanisms by which expansion of short tandem repeats causes disease: loss of function through transcription repression, RNA-mediated gain of function through gelation and sequestration of RNA-binding proteins, gain of function of canonically translated repeat-harbouring proteins, and repeat-associated non-AUG translation of toxic repeat peptides. Somatic repeat instability amplifies these mechanisms and influences both disease age of onset and tissue specificity of pathogenic features. We focus on the crosstalk between these disease mechanisms, and argue that they often synergize to drive pathogenesis. We also discuss the emerging native functions of repeat elements and how their dynamics might contribute to disease at a larger scale than currently appreciated. Lastly, we propose that lynchpins tying these disease mechanisms and native functions together offer promising therapeutic targets with potential shared applications across this class of human disorders.
Collapse
Affiliation(s)
- Indranil Malik
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Chase P Kelley
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics, Genetics Institute, University of Florida, Gainesville, FL, USA
- Genetics and Genomics Graduate Program, University of Florida, Gainesville, FL, USA
| | - Eric T Wang
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics, Genetics Institute, University of Florida, Gainesville, FL, USA.
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA.
- VA Ann Arbor Healthcare System, Ann Arbor, MI, USA.
| |
Collapse
|
55
|
Nuclear export and translation of circular repeat-containing intronic RNA in C9ORF72-ALS/FTD. Nat Commun 2021; 12:4908. [PMID: 34389711 PMCID: PMC8363653 DOI: 10.1038/s41467-021-25082-9] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Accepted: 07/16/2021] [Indexed: 12/14/2022] Open
Abstract
C9ORF72 hexanucleotide GGGGCC repeat expansion is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Repeat-containing RNA mediates toxicity through nuclear granules and dipeptide repeat (DPR) proteins produced by repeat-associated non-AUG translation. However, it remains unclear how the intron-localized repeats are exported and translated in the cytoplasm. We use single molecule imaging approach to examine the molecular identity and spatiotemporal dynamics of the repeat RNA. We demonstrate that the spliced intron with G-rich repeats is stabilized in a circular form due to defective lariat debranching. The spliced circular intron, instead of pre-mRNA, serves as the translation template. The NXF1-NXT1 pathway plays an important role in the nuclear export of the circular intron and modulates toxic DPR production. This study reveals an uncharacterized disease-causing RNA species mediated by repeat expansion and demonstrates the importance of RNA spatial localization to understand disease etiology. Hexanucleotide repeat expansion in the intron 1 of the C9ORF72 gene can cause amyotrophic lateral sclerosis (ALS) and frontal temporal dementia (FTD). Here the authors use single molecule imaging to show nuclear export and translation of circular repeat-containing C9ORF72 intronic RNA.
Collapse
|
56
|
Peric S, Rakocevic-Stojanovic V, Meola G. Cerebral involvement and related aspects in myotonic dystrophy type 2. Neuromuscul Disord 2021; 31:681-694. [PMID: 34244019 DOI: 10.1016/j.nmd.2021.06.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 06/02/2021] [Accepted: 06/03/2021] [Indexed: 01/18/2023]
Abstract
Myotonic dystrophy type 2 (DM2) is an autosomal dominant multisystemic disorder caused by CCTG repeats expansion in the first intron of the CNBP gene. In this review we focus on the brain involvement in DM2, including its pathogenic mechanisms, microstructural, macrostructural and functional brain changes, as well as the effects of all these impairments on patients' everyday life. We also try to understand how brain abnormalities in DM2 should be adequately measured and potentially treated. The most important pathogenetic mechanisms in DM2 are RNA gain-of-function and repeat-associated non-ATG (RAN) translation. One of the main neuroimaging findings in DM2 is the presence of diffuse periventricular white matter hyperintensity lesions (WMHLs). Brain atrophy has been described in DM2 patients, but it is not clear if it is mostly caused by a decrease of the white or gray matter volume. The most commonly reported specific cognitive symptoms in DM2 are dysexecutive syndrome, visuospatial and memory impairments. Fatigue, sleep-related disorders and pain are also frequent in DM2. The majority of key symptoms and signs in DM2 has a great influence on patients' daily lives, their psychological status, economic situation and quality of life.
Collapse
Affiliation(s)
- Stojan Peric
- Neurology Clinic, Clinical Center of Serbia, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | | | - Giovanni Meola
- Department of Neurorehabilitation Sciences, Casa Di Cura del Policlinico, Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| |
Collapse
|
57
|
Nishimura AL, Arias N. Synaptopathy Mechanisms in ALS Caused by C9orf72 Repeat Expansion. Front Cell Neurosci 2021; 15:660693. [PMID: 34140881 PMCID: PMC8203826 DOI: 10.3389/fncel.2021.660693] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 05/03/2021] [Indexed: 12/14/2022] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a complex neurodegenerative disease caused by degeneration of motor neurons (MNs). ALS pathogenic features include accumulation of misfolded proteins, glutamate excitotoxicity, mitochondrial dysfunction at distal axon terminals, and neuronal cytoskeleton changes. Synergies between loss of C9orf72 functions and gain of function by toxic effects of repeat expansions also contribute to C9orf72-mediated pathogenesis. However, the impact of haploinsufficiency of C9orf72 on neurons and in synaptic functions requires further examination. As the motor neurons degenerate, the disease symptoms will lead to neurotransmission deficiencies in the brain, spinal cord, and neuromuscular junction. Altered neuronal excitability, synaptic morphological changes, and C9orf72 protein and DPR localization at the synapses, suggest a potential involvement of C9orf72 at synapses. In this review article, we provide a conceptual framework for assessing the putative involvement of C9orf72 as a synaptopathy, and we explore the underlying and common disease mechanisms with other neurodegenerative diseases. Finally, we reflect on the major challenges of understanding C9orf72-ALS as a synaptopathy focusing on integrating mitochondrial and neuronal cytoskeleton degeneration as biomarkers and potential targets to treat ALS neurodegeneration.
Collapse
Affiliation(s)
- Agnes L Nishimura
- Department of Basic and Clinical Neuroscience, UK Dementia Research Institute, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Natalia Arias
- Department of Basic and Clinical Neuroscience, UK Dementia Research Institute, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom.,INEUROPA, Instituto de Neurociencias del Principado de Asturias, Oviedo, Spain
| |
Collapse
|
58
|
New developments in myotonic dystrophies from a multisystemic perspective. Curr Opin Neurol 2021; 34:738-747. [PMID: 33990102 DOI: 10.1097/wco.0000000000000964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW The multisystemic involvement of myotonic dystrophies (DMs) intricates disease monitoring, patients' care and trial design. This update of the multifaceted comorbidities observed in DMs aims to assist neurologists in the complex management of patients and to encourage further studies for still under-investigated aspects of the disease. RECENT FINDINGS We reviewed the most recent studies covering pathogenesis and clinical aspects of extra-muscular involvement in DM1 and DM2. The largest body of evidence regards the cardiac and respiratory features, for which experts' recommendations have been produced. Gastrointestinal symptoms emerge as one of the most prevalent complaints in DMs. The alteration of insulin signaling pathways, involved in gastrointestinal manifestations, carcinogenesis, muscle function, cognitive and endocrinological aspects, gain further relevance in the light of recent evidence of metformin efficacy in DM1. Still, too few studies are performed on large DM2 cohorts, so that current recommendations mainly rely on data gathered in DM1 that cannot be fully translated to DM2. SUMMARY Extra-muscular manifestations greatly contribute to the overall disease burden. A multidisciplinary approach is the key for the management of patients. Consensus-based recommendations for DM1 and DM2 allow high standards of care but further evidence are needed to implement these recommendations.
Collapse
|
59
|
Depienne C, Mandel JL. 30 years of repeat expansion disorders: What have we learned and what are the remaining challenges? Am J Hum Genet 2021; 108:764-785. [PMID: 33811808 PMCID: PMC8205997 DOI: 10.1016/j.ajhg.2021.03.011] [Citation(s) in RCA: 237] [Impact Index Per Article: 59.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 03/05/2021] [Indexed: 12/13/2022] Open
Abstract
Tandem repeats represent one of the most abundant class of variations in human genomes, which are polymorphic by nature and become highly unstable in a length-dependent manner. The expansion of repeat length across generations is a well-established process that results in human disorders mainly affecting the central nervous system. At least 50 disorders associated with expansion loci have been described to date, with half recognized only in the last ten years, as prior methodological difficulties limited their identification. These limitations still apply to the current widely used molecular diagnostic methods (exome or gene panels) and thus result in missed diagnosis detrimental to affected individuals and their families, especially for disorders that are very rare and/or clinically not recognizable. Most of these disorders have been identified through family-driven approaches and many others likely remain to be identified. The recent development of long-read technologies provides a unique opportunity to systematically investigate the contribution of tandem repeats and repeat expansions to the genetic architecture of human disorders. In this review, we summarize the current and most recent knowledge about the genetics of repeat expansion disorders and the diversity of their pathophysiological mechanisms and outline the perspectives of developing personalized treatments in the future.
Collapse
Affiliation(s)
- Christel Depienne
- Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, Essen, Germany; Institut du Cerveau et de la Moelle épinière (ICM), Sorbonne Université, UMR S 1127, Inserm U1127, CNRS UMR 7225, 75013 Paris, France.
| | - Jean-Louis Mandel
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch 67400, France; Centre National de la Recherche Scientifique, UMR 7104, Illkirch 67400, France; Institut National de la Santé et de la Recherche Médicale, U 1258, Illkirch 67400, France; Université de Strasbourg, Illkirch 67400, France; USIAS University of Strasbourg Institute of Advanced study, 67000 Strasbourg, France.
| |
Collapse
|
60
|
Tusi SK, Nguyen L, Thangaraju K, Li J, Cleary JD, Zu T, Ranum LPW. The alternative initiation factor eIF2A plays key role in RAN translation of myotonic dystrophy type 2 CCUG•CAGG repeats. Hum Mol Genet 2021; 30:1020-1029. [PMID: 33856033 DOI: 10.1093/hmg/ddab098] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 03/26/2021] [Accepted: 03/31/2021] [Indexed: 01/29/2023] Open
Abstract
Repeat-associated non-ATG (RAN) proteins have been reported in 11 microsatellite expansion disorders but the factors that allow RAN translation to occur and the effects of different repeat motifs and alternative AUG-like initiation codons are unclear. We studied the mechanisms of RAN translation across myotonic dystrophy type 2 (DM2) expansion transcripts with (CCUG) or without (CAGG) efficient alternative AUG-like codons. To better understand how DM2 LPAC and QAGR RAN proteins are expressed, we generated a series of CRISPR/Cas9-edited HEK293T cell lines. We show that LPAC and QAGR RAN protein levels are reduced in protein kinase R (PKR)-/- and PKR-like endoplasmic reticulum kinase (PERK)-/- cells, with more substantial reductions of CAGG-encoded QAGR in PKR-/- cells. Experiments using mutant eIF2α-S51A HEK293T cells show that p-eIF2α is required for QAGR production. In contrast, LPAC levels were only partially reduced in these cells, suggesting that both non-AUG and close-cognate initiation occur across CCUG RNAs. Overexpression of the alternative initiation factor eIF2A increases LPAC and QAGR protein levels but, notably, has a much larger effect on QAGR expressed from CAGG-expansion RNAs that lack efficient close-cognate codons. The effects of eIF2A on increasing LPAC are consistent with previous reports that eIF2A affects CUG-initiation translation. The observation that eIF2A also increases QAGR proteins is novel because CAGG expansion transcripts do not contain CUG or similarly efficient close-cognate AUG-like codons. For QAGR but not LPAC, the eIF2A-dependent increases are not seen when p-eIF2α is blocked. These data highlight the differential regulation of DM2 RAN proteins and eIF2A as a potential therapeutic target for DM2 and other RAN diseases.
Collapse
Affiliation(s)
- Solaleh Khoramian Tusi
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL 32610, USA
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
- Genetics Institute, University of Florida, Gainesville, FL 32610, USA
| | - Lien Nguyen
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL 32610, USA
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
- Genetics Institute, University of Florida, Gainesville, FL 32610, USA
| | - Kiruphagaran Thangaraju
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL 32610, USA
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
- Genetics Institute, University of Florida, Gainesville, FL 32610, USA
| | - Jian Li
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL 32610, USA
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
- Genetics Institute, University of Florida, Gainesville, FL 32610, USA
| | - John D Cleary
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL 32610, USA
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
- Genetics Institute, University of Florida, Gainesville, FL 32610, USA
| | - Tao Zu
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL 32610, USA
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
- Genetics Institute, University of Florida, Gainesville, FL 32610, USA
| | - Laura P W Ranum
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL 32610, USA
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
- Genetics Institute, University of Florida, Gainesville, FL 32610, USA
- McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
- Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL 32610, USA
| |
Collapse
|
61
|
Mechanisms of repeat-associated non-AUG translation in neurological microsatellite expansion disorders. Biochem Soc Trans 2021; 49:775-792. [PMID: 33729487 PMCID: PMC8106499 DOI: 10.1042/bst20200690] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 02/20/2021] [Accepted: 02/23/2021] [Indexed: 02/08/2023]
Abstract
Repeat-associated non-AUG (RAN) translation was discovered in 2011 in spinocerebellar ataxia type 8 (SCA8) and myotonic dystrophy type 1 (DM1). This non-canonical form of translation occurs in all reading frames from both coding and non-coding regions of sense and antisense transcripts carrying expansions of trinucleotide to hexanucleotide repeat sequences. RAN translation has since been reported in 7 of the 53 known microsatellite expansion disorders which mainly present with neurodegenerative features. RAN translation leads to the biosynthesis of low-complexity polymeric repeat proteins with aggregating and cytotoxic properties. However, the molecular mechanisms and protein factors involved in assembling functional ribosomes in absence of canonical AUG start codons remain poorly characterised while secondary repeat RNA structures play key roles in initiating RAN translation. Here, we briefly review the repeat expansion disorders, their complex pathogenesis and the mechanisms of physiological translation initiation together with the known factors involved in RAN translation. Finally, we discuss research challenges surrounding the understanding of pathogenesis and future directions that may provide opportunities for the development of novel therapeutic approaches for this group of incurable neurodegenerative diseases.
Collapse
|
62
|
Otero BA, Poukalov K, Hildebrandt RP, Thornton CA, Jinnai K, Fujimura H, Kimura T, Hagerman KA, Sampson JB, Day JW, Wang ET. Transcriptome alterations in myotonic dystrophy frontal cortex. Cell Rep 2021; 34:108634. [PMID: 33472074 PMCID: PMC9272850 DOI: 10.1016/j.celrep.2020.108634] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 11/16/2020] [Accepted: 12/21/2020] [Indexed: 12/13/2022] Open
Abstract
Myotonic dystrophy (DM) is caused by expanded CTG/CCTG repeats, causing symptoms in skeletal muscle, heart, and central nervous system (CNS). CNS issues are debilitating and include hypersomnolence, executive dysfunction, white matter atrophy, and neurofibrillary tangles. Here, we generate RNA-seq transcriptomes from DM and unaffected frontal cortex and identify 130 high-confidence splicing changes, most occurring only in cortex, not skeletal muscle or heart. Mis-spliced exons occur in neurotransmitter receptors, ion channels, and synaptic scaffolds, and GRIP1 mis-splicing modulates kinesin association. Optical mapping of expanded CTG repeats reveals extreme mosaicism, with some alleles showing >1,000 CTGs. Mis-splicing severity correlates with CTG repeat length across individuals. Upregulated genes tend to be microglial and endothelial, suggesting neuroinflammation, and downregulated genes tend to be neuronal. Many gene expression changes strongly correlate with mis-splicing, suggesting candidate biomarkers of disease. These findings provide a framework for mechanistic and therapeutic studies of the DM CNS.
Collapse
Affiliation(s)
- Brittney A Otero
- Department of Molecular Genetics & Microbiology, Center for NeuroGenetics, Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Kiril Poukalov
- Department of Molecular Genetics & Microbiology, Center for NeuroGenetics, Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Ryan P Hildebrandt
- Department of Molecular Genetics & Microbiology, Center for NeuroGenetics, Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Charles A Thornton
- Department of Neurology, University of Rochester Medical Center, Rochester, NY, USA
| | - Kenji Jinnai
- Department of Neurology, National Hospital Organization Hyogo-Chuo Hospital, Sanda, Japan
| | - Harutoshi Fujimura
- Department of Neurology, National Hospital Organization Toneyama Hospital, Osaka, Japan
| | - Takashi Kimura
- Department of Neurology, Hyogo College of Medicine, Nichinomiya, Japan
| | | | | | - John W Day
- Department of Neurology, Stanford University, Palo Alto, CA, USA
| | - Eric T Wang
- Department of Molecular Genetics & Microbiology, Center for NeuroGenetics, Genetics Institute, University of Florida, Gainesville, FL, USA.
| |
Collapse
|
63
|
Johnson SJ, Cooper TA. Overlapping mechanisms of lncRNA and expanded microsatellite RNA. WILEY INTERDISCIPLINARY REVIEWS. RNA 2021; 12:e1634. [PMID: 33191580 PMCID: PMC7880542 DOI: 10.1002/wrna.1634] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 10/14/2020] [Accepted: 10/20/2020] [Indexed: 12/15/2022]
Abstract
RNA has major regulatory roles in a wide range of biological processes and a surge of RNA research has led to the classification of numerous functional RNA species. One example is long noncoding RNAs (lncRNAs) that are structurally complex transcripts >200 nucleotides (nt) in length and lacking a canonical open reading frame (ORF). Despite a general lack of sequence conservation and low expression levels, many lncRNAs have been shown to have functionality in diverse biological processes as well as in mechanisms of disease. In parallel with the growing understanding of lncRNA functions, there is a growing subset of microsatellite expansion disorders in which the primary mechanism of pathogenesis is an RNA gain of function arising from RNA transcripts from the mutant allele. Microsatellite expansion disorders are caused by an expansion of short (3-10 nt) repeats located within coding genes. Expanded repeat-containing RNA mediates toxicity through multiple mechanisms, the details of which remain only partially understood. The purpose of this review is to highlight the links between functional mechanisms of lncRNAs and the potential pathogenic mechanisms of expanded microsatellite RNA. These shared mechanisms include protein sequestration, peptide translation, micro-RNA (miRNA) processing, and miRNA sequestration. Recognizing the parallels between the normal functions of lncRNAs and the negative impact of expanded microsatellite RNA on biological processes can provide reciprocal understanding to the roles of both RNA species. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications RNA in Disease and Development > RNA in Disease.
Collapse
Affiliation(s)
- Sara J Johnson
- Department of Molecular & Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Thomas A Cooper
- Department of Molecular & Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, Texas, USA
- Department of Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, USA
| |
Collapse
|
64
|
Meola G. Myotonic dystrophy type 2: the 2020 update. ACTA MYOLOGICA : MYOPATHIES AND CARDIOMYOPATHIES : OFFICIAL JOURNAL OF THE MEDITERRANEAN SOCIETY OF MYOLOGY 2020; 39:222-234. [PMID: 33458578 PMCID: PMC7783423 DOI: 10.36185/2532-1900-026] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 11/09/2020] [Indexed: 12/26/2022]
Abstract
The myotonic dystrophies are the commonest cause of adult-onset muscular dystrophy. Phenotypes of DM1 and DM2 are similar, but there are some important differences, including the presence or absence of congenital form, muscles primarily affected (distal vs proximal), involved muscle fiber types (type 1 vs type 2 fibers), and some associated multisystemic phenotypes. There is currently no cure for the myotonic dystrophies but effective management significantly reduces the morbidity and mortality of patients. For the enormous understanding of the molecular pathogenesis of myotonic dystrophy type 1 and myotonic dystrophy type 2, these diseases are now called "spliceopathies" and are mediated by a primary disorder of RNA rather than proteins. Despite clinical and genetic similarities, myotonic dystrophy type 1 and type 2 are distinct disorders requiring different diagnostic and management strategies. Gene therapy for myotonic dystrophy type 1 and myotonic dystrophy type 2 appears to be very close and the near future is an exciting time for clinicians and patients.
Collapse
Affiliation(s)
- Giovanni Meola
- Department of Biomedical Sciences for Health, University of Milan, Italy.,Department of Neurorehabilitation Sciences, Casa di Cura del Policlinico, Milan, Italy
| |
Collapse
|
65
|
Castro AF, Loureiro JR, Bessa J, Silveira I. Antisense Transcription across Nucleotide Repeat Expansions in Neurodegenerative and Neuromuscular Diseases: Progress and Mysteries. Genes (Basel) 2020; 11:E1418. [PMID: 33261024 PMCID: PMC7760973 DOI: 10.3390/genes11121418] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/24/2020] [Accepted: 11/24/2020] [Indexed: 12/14/2022] Open
Abstract
Unstable repeat expansions and insertions cause more than 30 neurodegenerative and neuromuscular diseases. Remarkably, bidirectional transcription of repeat expansions has been identified in at least 14 of these diseases. More remarkably, a growing number of studies has been showing that both sense and antisense repeat RNAs are able to dysregulate important cellular pathways, contributing together to the observed clinical phenotype. Notably, antisense repeat RNAs from spinocerebellar ataxia type 7, myotonic dystrophy type 1, Huntington's disease and frontotemporal dementia/amyotrophic lateral sclerosis associated genes have been implicated in transcriptional regulation of sense gene expression, acting either at a transcriptional or posttranscriptional level. The recent evidence that antisense repeat RNAs could modulate gene expression broadens our understanding of the pathogenic pathways and adds more complexity to the development of therapeutic strategies for these disorders. In this review, we cover the amazing progress made in the understanding of the pathogenic mechanisms associated with repeat expansion neurodegenerative and neuromuscular diseases with a focus on the impact of antisense repeat transcription in the development of efficient therapies.
Collapse
Affiliation(s)
- Ana F. Castro
- Genetics of Cognitive Dysfunction Laboratory, i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (A.F.C.); (J.R.L.)
- IBMC-Institute for Molecular and Cell Biology, Universidade do Porto, 4200-135 Porto, Portugal;
- ICBAS, Universidade do Porto, 4050-313 Porto, Portugal
| | - Joana R. Loureiro
- Genetics of Cognitive Dysfunction Laboratory, i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (A.F.C.); (J.R.L.)
- IBMC-Institute for Molecular and Cell Biology, Universidade do Porto, 4200-135 Porto, Portugal;
| | - José Bessa
- IBMC-Institute for Molecular and Cell Biology, Universidade do Porto, 4200-135 Porto, Portugal;
- Vertebrate Development and Regeneration Laboratory, i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
| | - Isabel Silveira
- Genetics of Cognitive Dysfunction Laboratory, i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (A.F.C.); (J.R.L.)
- IBMC-Institute for Molecular and Cell Biology, Universidade do Porto, 4200-135 Porto, Portugal;
| |
Collapse
|
66
|
Jazurek-Ciesiolka M, Ciesiolka A, Komur AA, Urbanek-Trzeciak MO, Krzyzosiak WJ, Fiszer A. RAN Translation of the Expanded CAG Repeats in the SCA3 Disease Context. J Mol Biol 2020; 432:166699. [PMID: 33157084 DOI: 10.1016/j.jmb.2020.10.033] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 10/26/2020] [Accepted: 10/26/2020] [Indexed: 01/08/2023]
Abstract
Spinocerebellar ataxia type 3 (SCA3) is a progressive neurodegenerative disorder caused by a CAG repeat expansion in the ATXN3 gene encoding the ataxin-3 protein. Despite extensive research the exact pathogenic mechanisms of SCA3 are still not understood in depth. In the present study, to gain insight into the toxicity induced by the expanded CAG repeats in SCA3, we comprehensively investigated repeat-associated non-ATG (RAN) translation in various cellular models expressing translated or non-canonically translated ATXN3 sequences with an increasing number of CAG repeats. We demonstrate that two SCA3 RAN proteins, polyglutamine (polyQ) and polyalanine (polyA), are found only in the case of CAG repeats of pathogenic length. Despite having distinct cellular localization, RAN polyQ and RAN polyA proteins are very often coexpressed in the same cell, impairing nuclear integrity and inducing apoptosis. We provide for the first time mechanistic insights into SCA3 RAN translation indicating that ATXN3 sequences surrounding the repeat region have an impact on SCA3 RAN translation initiation and efficiency. We revealed that RAN translation of polyQ proteins starts at non-cognate codons upstream of the CAG repeats, whereas RAN polyA proteins are likely translated within repeats. Furthermore, integrated stress response activation enhances SCA3 RAN translation. Our findings suggest that the ATXN3 sequence context plays an important role in triggering SCA3 RAN translation and that SCA3 RAN proteins may cause cellular toxicity.
Collapse
Affiliation(s)
- Magdalena Jazurek-Ciesiolka
- Department of Medical Biotechnology, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland.
| | - Adam Ciesiolka
- Department of Medical Biotechnology, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Alicja A Komur
- Department of Medical Biotechnology, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Martyna O Urbanek-Trzeciak
- Department of Medical Biotechnology, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Wlodzimierz J Krzyzosiak
- Department of Medical Biotechnology, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Agnieszka Fiszer
- Department of Medical Biotechnology, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland.
| |
Collapse
|
67
|
Ramesh N, Daley EL, Gleixner AM, Mann JR, Kour S, Mawrie D, Anderson EN, Kofler J, Donnelly CJ, Kiskinis E, Pandey UB. RNA dependent suppression of C9orf72 ALS/FTD associated neurodegeneration by Matrin-3. Acta Neuropathol Commun 2020; 8:177. [PMID: 33129345 PMCID: PMC7603783 DOI: 10.1186/s40478-020-01060-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 10/14/2020] [Indexed: 12/11/2022] Open
Abstract
The most common genetic cause of amyotrophic lateral sclerosis (ALS) is a GGGGCC (G4C2) hexanucleotide repeat expansions in first intron of the C9orf72 gene. The accumulation of repetitive RNA sequences can mediate toxicity potentially through the formation of intranuclear RNA foci that sequester key RNA-binding proteins (RBPs), and non-ATG mediated translation into toxic dipeptide protein repeats. However, the contribution of RBP sequestration to the mechanisms underlying RNA-mediated toxicity remain unknown. Here we show that the ALS-associated RNA-binding protein, Matrin-3 (MATR3), colocalizes with G4C2 RNA foci in patient tissues as well as iPSC-derived motor neurons harboring the C9orf72 mutation. Hyperexpansion of C9 repeats perturbed subcellular distribution and levels of endogenous MATR3 in C9-ALS patient-derived motor neurons. Interestingly, we observed that ectopic expression of human MATR3 strongly mitigates G4C2-mediated neurodegeneration in vivo. MATR3-mediated suppression of C9 toxicity was dependent on the RNA-binding domain of MATR3. Importantly, we found that expression of MATR3 reduced the levels of RAN-translation products in mammalian cells in an RNA-dependent manner. Finally, we have shown that knocking down endogenous MATR3 in C9-ALS patient-derived iPSC neurons decreased the presence of G4C2 RNA foci in the nucleus. Overall, these studies suggest that MATR3 genetically modifies the neuropathological and the pathobiology of C9orf72 ALS through modulating the RNA foci and RAN translation.
Collapse
Affiliation(s)
- Nandini Ramesh
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
- Department of Human Genetics, School of Public Health, School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Elizabeth L Daley
- The Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Amanda M Gleixner
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- LiveLikeLou Center for ALS Research, University of Pittsburgh Brain Institute, Pittsburgh, PA, USA
| | - Jacob R Mann
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Sukhleen Kour
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Darilang Mawrie
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Eric N Anderson
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Julia Kofler
- Department of Pathology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Christopher J Donnelly
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- LiveLikeLou Center for ALS Research, University of Pittsburgh Brain Institute, Pittsburgh, PA, USA
| | - Evangelos Kiskinis
- The Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
- Simpson Querrey Institute, Northwestern University, Chicago, IL, 60611, USA
| | - Udai Bhan Pandey
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
- Department of Human Genetics, School of Public Health, School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA.
| |
Collapse
|
68
|
Fautsch MP, Wieben ED, Baratz KH, Bhattacharyya N, Sadan AN, Hafford-Tear NJ, Tuft SJ, Davidson AE. TCF4-mediated Fuchs endothelial corneal dystrophy: Insights into a common trinucleotide repeat-associated disease. Prog Retin Eye Res 2020; 81:100883. [PMID: 32735996 PMCID: PMC7988464 DOI: 10.1016/j.preteyeres.2020.100883] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/24/2020] [Accepted: 07/04/2020] [Indexed: 12/13/2022]
Abstract
Fuchs endothelial corneal dystrophy (FECD) is a common cause for heritable visual loss in the elderly. Since the first description of an association between FECD and common polymorphisms situated within the transcription factor 4 (TCF4) gene, genetic and molecular studies have implicated an intronic CTG trinucleotide repeat (CTG18.1) expansion as a causal variant in the majority of FECD patients. To date, several non-mutually exclusive mechanisms have been proposed that drive and/or exacerbate the onset of disease. These mechanisms include (i) TCF4 dysregulation; (ii) toxic gain-of-function from TCF4 repeat-containing RNA; (iii) toxic gain-of-function from repeat-associated non-AUG dependent (RAN) translation; and (iv) somatic instability of CTG18.1. However, the relative contribution of these proposed mechanisms in disease pathogenesis is currently unknown. In this review, we summarise research implicating the repeat expansion in disease pathogenesis, define the phenotype-genotype correlations between FECD and CTG18.1 expansion, and provide an update on research tools that are available to study FECD as a trinucleotide repeat expansion disease. Furthermore, ongoing international research efforts to develop novel CTG18.1 expansion-mediated FECD therapeutics are highlighted and we provide a forward-thinking perspective on key unanswered questions that remain in the field. FECD is a common, age-related corneal dystrophy. The majority of cases are associated with expansion of a CTG repeat (CTG18.1). FECD is the most common trinucleotide repeat expansion disease in humans. Evidence supports multiple molecular mechanisms underlying the pathophysiology. Novel CTG18.1-targeted therapeutics are in development.
Collapse
Affiliation(s)
- Michael P Fautsch
- Department of Ophthalmology, 200 1st St SW, Mayo Clinic, Rochester, MN, 55905, USA.
| | - Eric D Wieben
- Department of Biochemistry and Molecular Biology, 200 1st St SW, Mayo Clinic, Rochester, MN, USA.
| | - Keith H Baratz
- Department of Ophthalmology, 200 1st St SW, Mayo Clinic, Rochester, MN, 55905, USA.
| | | | - Amanda N Sadan
- University College London Institute of Ophthalmology, London, ECIV 9EL, UK.
| | | | - Stephen J Tuft
- University College London Institute of Ophthalmology, London, ECIV 9EL, UK; Moorfields Eye Hospital, London, EC1V 2PD, UK.
| | - Alice E Davidson
- University College London Institute of Ophthalmology, London, ECIV 9EL, UK.
| |
Collapse
|
69
|
McEachin ZT, Gendron TF, Raj N, García-Murias M, Banerjee A, Purcell RH, Ward PJ, Todd TW, Merritt-Garza ME, Jansen-West K, Hales CM, García-Sobrino T, Quintáns B, Holler CJ, Taylor G, San Millán B, Teijeira S, Yamashita T, Ohkubo R, Boulis NM, Xu C, Wen Z, Streichenberger N, Fogel BL, Kukar T, Abe K, Dickson DW, Arias M, Glass JD, Jiang J, Tansey MG, Sobrido MJ, Petrucelli L, Rossoll W, Bassell GJ. Chimeric Peptide Species Contribute to Divergent Dipeptide Repeat Pathology in c9ALS/FTD and SCA36. Neuron 2020; 107:292-305.e6. [PMID: 32375063 PMCID: PMC8138626 DOI: 10.1016/j.neuron.2020.04.011] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 03/11/2020] [Accepted: 04/06/2020] [Indexed: 12/13/2022]
Abstract
GGGGCC hexanucleotide repeat expansions (HREs) in C9orf72 cause amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) and lead to the production of aggregating dipeptide repeat proteins (DPRs) via repeat associated non-AUG (RAN) translation. Here, we show the similar intronic GGCCTG HREs that causes spinocerebellar ataxia type 36 (SCA36) is also translated into DPRs, including poly(GP) and poly(PR). We demonstrate that poly(GP) is more abundant in SCA36 compared to c9ALS/FTD patient tissue due to canonical AUG-mediated translation from intron-retained GGCCTG repeat RNAs. However, the frequency of the antisense RAN translation product poly(PR) is comparable between c9ALS/FTD and SCA36 patient samples. Interestingly, in SCA36 patient tissue, poly(GP) exists as a soluble species, and no TDP-43 pathology is present. We show that aggregate-prone chimeric DPR (cDPR) species underlie the divergent DPR pathology between c9ALS/FTD and SCA36. These findings reveal key differences in translation, solubility, and protein aggregation of DPRs between c9ALS/FTD and SCA36.
Collapse
Affiliation(s)
- Zachary T McEachin
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; Laboratory for Translational Cell Biology, Emory University, Atlanta, GA 30322, USA; Wallace H. Coulter Graduate Program in Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, GA 30332, USA.
| | - Tania F Gendron
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Nisha Raj
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; Laboratory for Translational Cell Biology, Emory University, Atlanta, GA 30322, USA
| | - María García-Murias
- Centro de Investigación Biomédica en red de Enfermedades Raras (CIBERER), Santiago de Compostela, Spain; Neurogenetics Research Group, Instituto de Investigación Sanitaria (IDIS), Hospital Clínico Universitario, SERGAS, Santiago de Compostela, Spain
| | - Anwesha Banerjee
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA
| | - Ryan H Purcell
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; Laboratory for Translational Cell Biology, Emory University, Atlanta, GA 30322, USA
| | - Patricia J Ward
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA
| | - Tiffany W Todd
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | | | - Karen Jansen-West
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Chadwick M Hales
- Department of Neurology, Emory University, Atlanta, GA 30322, USA
| | - Tania García-Sobrino
- Department of Neurology, Hospital Clínico Universitario, SERGAS, Santiago de Compostela, Spain
| | - Beatriz Quintáns
- Centro de Investigación Biomédica en red de Enfermedades Raras (CIBERER), Santiago de Compostela, Spain; Neurogenetics Research Group, Instituto de Investigación Sanitaria (IDIS), Hospital Clínico Universitario, SERGAS, Santiago de Compostela, Spain
| | - Christopher J Holler
- Department of Pharmacology & Chemical Biology, Emory University, Atlanta, GA 30322, USA
| | - Georgia Taylor
- Department of Pharmacology & Chemical Biology, Emory University, Atlanta, GA 30322, USA
| | - Beatriz San Millán
- Rare Diseases and Pediatric Medicine Research Group, Galicia Sur Health Research Institute (IIS Galicia Sur), SERGAS-UVIGO, Vigo, Spain; Pathology Department, Complexo Hospitalario Universitario de Vigo (CHUVI), SERGAS, Vigo, Spain
| | - Susana Teijeira
- Rare Diseases and Pediatric Medicine Research Group, Galicia Sur Health Research Institute (IIS Galicia Sur), SERGAS-UVIGO, Vigo, Spain; Pathology Department, Complexo Hospitalario Universitario de Vigo (CHUVI), SERGAS, Vigo, Spain
| | - Toru Yamashita
- Department of Neurology, Okayama University, Okayama, Japan
| | - Ryuichi Ohkubo
- Department of Neurology, Fujimoto General Hospital, Miyazaki, Japan
| | - Nicholas M Boulis
- Department of Neurosurgery, Emory University, Atlanta, GA 30322, USA
| | - Chongchong Xu
- Department of Psychiatry & Behavioral Sciences, Emory University, Atlanta, GA 30322, USA
| | - Zhexing Wen
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; Laboratory for Translational Cell Biology, Emory University, Atlanta, GA 30322, USA; Department of Neurology, Emory University, Atlanta, GA 30322, USA; Department of Psychiatry & Behavioral Sciences, Emory University, Atlanta, GA 30322, USA
| | - Nathalie Streichenberger
- Hospices Civils de Lyon, Lyon, France; Université Claude Bernard Lyon, Lyon, France; Institut NeuroMyogène CNRS UMR 5310
| | | | - Brent L Fogel
- Department of Neurology & Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Thomas Kukar
- Department of Neurology, Emory University, Atlanta, GA 30322, USA; Department of Pharmacology & Chemical Biology, Emory University, Atlanta, GA 30322, USA
| | - Koji Abe
- Department of Neurology, Okayama University, Okayama, Japan
| | - Dennis W Dickson
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Manuel Arias
- Neurogenetics Research Group, Instituto de Investigación Sanitaria (IDIS), Hospital Clínico Universitario, SERGAS, Santiago de Compostela, Spain; Department of Neurology, Hospital Clínico Universitario, SERGAS, Santiago de Compostela, Spain
| | - Jonathan D Glass
- Department of Neurology, Emory University, Atlanta, GA 30322, USA
| | - Jie Jiang
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA
| | - Malú G Tansey
- Department of Neuroscience, University of Florida, Gainesville, FL 32607, USA; Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL 32607, USA; Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL 32607, USA
| | - María-Jesús Sobrido
- Centro de Investigación Biomédica en red de Enfermedades Raras (CIBERER), Santiago de Compostela, Spain; Neurogenetics Research Group, Instituto de Investigación Sanitaria (IDIS), Hospital Clínico Universitario, SERGAS, Santiago de Compostela, Spain
| | - Leonard Petrucelli
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Wilfried Rossoll
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Gary J Bassell
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; Laboratory for Translational Cell Biology, Emory University, Atlanta, GA 30322, USA; Wallace H. Coulter Graduate Program in Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, GA 30332, USA; Department of Neurology, Emory University, Atlanta, GA 30322, USA.
| |
Collapse
|
70
|
Swinnen B, Robberecht W, Van Den Bosch L. RNA toxicity in non-coding repeat expansion disorders. EMBO J 2020; 39:e101112. [PMID: 31721251 PMCID: PMC6939197 DOI: 10.15252/embj.2018101112] [Citation(s) in RCA: 134] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 09/30/2019] [Accepted: 10/09/2019] [Indexed: 12/11/2022] Open
Abstract
Several neurodegenerative disorders like amyotrophic lateral sclerosis (ALS) and spinocerebellar ataxia (SCA) are caused by non-coding nucleotide repeat expansions. Different pathogenic mechanisms may underlie these non-coding repeat expansion disorders. While gain-of-function mechanisms, such as toxicity associated with expression of repeat RNA or toxicity associated with repeat-associated non-ATG (RAN) products, are most frequently connected with these disorders, loss-of-function mechanisms have also been implicated. We review the different pathways that have been linked to non-coding repeat expansion disorders such as C9ORF72-linked ALS/frontotemporal dementia (FTD), myotonic dystrophy, fragile X tremor/ataxia syndrome (FXTAS), SCA, and Huntington's disease-like 2. We discuss modes of RNA toxicity focusing on the identity and the interacting partners of the toxic RNA species. Using the C9ORF72 ALS/FTD paradigm, we further explore the efforts and different methods used to disentangle RNA vs. RAN toxicity. Overall, we conclude that there is ample evidence for a role of RNA toxicity in non-coding repeat expansion diseases.
Collapse
Affiliation(s)
- Bart Swinnen
- Department of NeurosciencesExperimental NeurologyLeuven Brain Institute (LBI)KU Leuven – University of LeuvenLeuvenBelgium
- Laboratory of NeurobiologyVIB, Center for Brain & Disease ResearchLeuvenBelgium
- Department of NeurologyUniversity Hospitals LeuvenLeuvenBelgium
| | - Wim Robberecht
- Department of NeurosciencesExperimental NeurologyLeuven Brain Institute (LBI)KU Leuven – University of LeuvenLeuvenBelgium
- Laboratory of NeurobiologyVIB, Center for Brain & Disease ResearchLeuvenBelgium
- Department of NeurologyUniversity Hospitals LeuvenLeuvenBelgium
| | - Ludo Van Den Bosch
- Department of NeurosciencesExperimental NeurologyLeuven Brain Institute (LBI)KU Leuven – University of LeuvenLeuvenBelgium
- Laboratory of NeurobiologyVIB, Center for Brain & Disease ResearchLeuvenBelgium
| |
Collapse
|
71
|
Nussbacher JK, Tabet R, Yeo GW, Lagier-Tourenne C. Disruption of RNA Metabolism in Neurological Diseases and Emerging Therapeutic Interventions. Neuron 2019; 102:294-320. [PMID: 30998900 DOI: 10.1016/j.neuron.2019.03.014] [Citation(s) in RCA: 184] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 01/24/2019] [Accepted: 03/12/2019] [Indexed: 02/06/2023]
Abstract
RNA binding proteins are critical to the maintenance of the transcriptome via controlled regulation of RNA processing and transport. Alterations of these proteins impact multiple steps of the RNA life cycle resulting in various molecular phenotypes such as aberrant RNA splicing, transport, and stability. Disruption of RNA binding proteins and widespread RNA processing defects are increasingly recognized as critical determinants of neurological diseases. Here, we describe distinct mechanisms by which the homeostasis of RNA binding proteins is compromised in neurological disorders through their reduced expression level, increased propensity to aggregate or sequestration by abnormal RNAs. These mechanisms all converge toward altered neuronal function highlighting the susceptibility of neurons to deleterious changes in RNA expression and the central role of RNA binding proteins in preserving neuronal integrity. Emerging therapeutic approaches to mitigate or reverse alterations of RNA binding proteins in neurological diseases are discussed.
Collapse
Affiliation(s)
- Julia K Nussbacher
- Department of Cellular and Molecular Medicine, Institute for Genomic Medicine, UCSD Stem Cell Program, University of California, San Diego, La Jolla, CA, USA
| | - Ricardos Tabet
- Department of Neurology, The Sean M. Healey and AMG Center for ALS at Mass General, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA; Broad Institute of Harvard University and MIT, Cambridge, MA 02142, USA
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, Institute for Genomic Medicine, UCSD Stem Cell Program, University of California, San Diego, La Jolla, CA, USA.
| | - Clotilde Lagier-Tourenne
- Department of Neurology, The Sean M. Healey and AMG Center for ALS at Mass General, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA; Broad Institute of Harvard University and MIT, Cambridge, MA 02142, USA.
| |
Collapse
|
72
|
Cook C, Petrucelli L. Genetic Convergence Brings Clarity to the Enigmatic Red Line in ALS. Neuron 2019; 101:1057-1069. [PMID: 30897357 DOI: 10.1016/j.neuron.2019.02.032] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 02/07/2019] [Accepted: 02/19/2019] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is an aggressive neurodegenerative disorder that orchestrates an attack on the motor nervous system that is unrelenting. Recent discoveries into the pathogenic consequences of repeat expansions in C9ORF72, which are the most common genetic cause of ALS, combined with the identification of new genetic mutations are providing novel insight into the underlying mechanism(s) that cause ALS. In particular, the myriad of functions linked to ALS-associated genes have collectively implicated four main pathways in disease pathogenesis, including RNA metabolism and translational biology; protein quality control; cytoskeletal integrity and trafficking; and mitochondrial function and transport. Through the identification of common disease mechanisms on which multiple ALS genes converge, key targets for potential therapeutic intervention are highlighted.
Collapse
Affiliation(s)
- Casey Cook
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA; Neurobiology of Disease Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Jacksonville, FL, USA
| | - Leonard Petrucelli
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA; Neurobiology of Disease Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Jacksonville, FL, USA.
| |
Collapse
|
73
|
Green KM, Sheth UJ, Flores BN, Wright SE, Sutter AB, Kearse MG, Barmada SJ, Ivanova MI, Todd PK. High-throughput screening yields several small-molecule inhibitors of repeat-associated non-AUG translation. J Biol Chem 2019; 294:18624-18638. [PMID: 31649034 DOI: 10.1074/jbc.ra119.009951] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 10/16/2019] [Indexed: 12/18/2022] Open
Abstract
Repeat-associated non-AUG (RAN) translation is a noncanonical translation initiation event that occurs at nucleotide-repeat expansion mutations that are associated with several neurodegenerative diseases, including fragile X-associated tremor ataxia syndrome (FXTAS), ALS, and frontotemporal dementia (FTD). Translation of expanded repeats produces toxic proteins that accumulate in human brains and contribute to disease pathogenesis. Consequently, RAN translation constitutes a potentially important therapeutic target for managing multiple neurodegenerative disorders. Here, we adapted a previously developed RAN translation assay to a high-throughput format to screen 3,253 bioactive compounds for inhibition of RAN translation of expanded CGG repeats associated with FXTAS. We identified five diverse small molecules that dose-dependently inhibited CGG RAN translation, while relatively sparing canonical translation. All five compounds also inhibited RAN translation of expanded GGGGCC repeats associated with ALS and FTD. Using CD and native gel analyses, we found evidence that three of these compounds, BIX01294, CP-31398, and propidium iodide, bind directly to the repeat RNAs. These findings provide proof-of-principle supporting the development of selective small-molecule RAN translation inhibitors that act across multiple disease-causing repeats.
Collapse
Affiliation(s)
- Katelyn M Green
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109; Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan 48109
| | - Udit J Sheth
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109
| | - Brittany N Flores
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109; Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan 48109
| | - Shannon E Wright
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109
| | - Alexandra B Sutter
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109
| | - Michael G Kearse
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109; Department of Biological Chemistry and Pharmacology, Center for RNA Biology, Ohio State University, Columbus, Ohio 43210
| | - Sami J Barmada
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109; Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan 48109
| | - Magdalena I Ivanova
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109; Biophysics Program, University of Michigan, Ann Arbor, Michigan 48109
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109; Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan 48109; Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, Michigan 48105.
| |
Collapse
|
74
|
Ishikawa K, Nagai Y. Molecular Mechanisms and Future Therapeutics for Spinocerebellar Ataxia Type 31 (SCA31). Neurotherapeutics 2019; 16:1106-1114. [PMID: 31755042 PMCID: PMC6985187 DOI: 10.1007/s13311-019-00804-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Spinocerebellar ataxia type 31 (SCA31) is one of the autosomal-dominant neurodegenerative disorders that shows progressive cerebellar ataxia as a cardinal symptom. This disease is caused by a 2.5- to 3.8-kb-long complex pentanucleotide repeat containing (TGGAA)n, (TAGAA)n, (TAAAA)n, and (TAAAATAGAA)n in an intron of the gene called BEAN1 (brain expressed, associated with Nedd4). By comparing various pentanucleotide repeats in this particular locus among control Japanese and Caucasian populations, it was found that (TGGAA)n was the only sequence segregating with SCA31, strongly suggesting the pathogenicity of (TGGAA)n. The complex repeat also lies in an intron of another gene, TK2 (thymidine kinase 2), which is transcribed in the opposite direction, indicating that the complex repeat is bi-directionally transcribed as noncoding repeats. In SCA31 human brains, (UGGAA)n, the BEAN1 transcript of SCA31 mutation was found to form abnormal RNA structures called RNA foci in cerebellar Purkinje cell nuclei. Subsequent RNA pulldown analysis disclosed that (UGGAA)n binds to RNA-binding proteins TDP-43, FUS, and hnRNP A2/B1. In fact, TDP-43 was found to co-localize with RNA foci in human SCA31 Purkinje cells. To dissect the pathogenesis of (UGGAA)n in SCA31, we generated transgenic fly models of SCA31 by overexpressing SCA31 complex pentanucleotide repeats in Drosophila. We found that the toxicity of (UGGAA)n is length- and expression level-dependent, and it was dampened by co-expressing TDP-43, FUS, and hnRNP A2/B1. Further investigation revealed that TDP-43 ameliorates (UGGAA)n toxicity by directly fixing the abnormal structure of (UGGAA)n. This led us to propose that TDP-43 acts as an RNA chaperone against toxic (UGGAA)n. Further research on the role of RNA-binding proteins as RNA chaperones may provide a novel therapeutic strategy for SCA31.
Collapse
Affiliation(s)
- Kinya Ishikawa
- Department of Neurology and Neurological Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
- The Center for Personalized Medicine for Healthy Aging, Tokyo Medical and Dental University, Tokyo, Japan.
| | - Yoshitaka Nagai
- Department of Neurotherapeutics, Osaka University Graduate School of Medicine, Osaka, Japan
- Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Japan
| |
Collapse
|
75
|
Reddy K, Jenquin JR, Cleary JD, Berglund JA. Mitigating RNA Toxicity in Myotonic Dystrophy using Small Molecules. Int J Mol Sci 2019; 20:E4017. [PMID: 31426500 PMCID: PMC6720693 DOI: 10.3390/ijms20164017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/13/2019] [Accepted: 08/16/2019] [Indexed: 12/26/2022] Open
Abstract
This review, one in a series on myotonic dystrophy (DM), is focused on the development and potential use of small molecules as therapeutics for DM. The complex mechanisms and pathogenesis of DM are covered in the associated reviews. Here, we examine the various small molecule approaches taken to target the DNA, RNA, and proteins that contribute to disease onset and progression in myotonic dystrophy type 1 (DM1) and 2 (DM2).
Collapse
Affiliation(s)
- Kaalak Reddy
- The RNA Institute, University at Albany-SUNY, Albany, NY 12222, USA.
| | - Jana R Jenquin
- Center for NeuroGenetics and Biochemistry & Molecular Biology, University of Florida, Gainesville, FL 32608, USA
| | - John D Cleary
- The RNA Institute, University at Albany-SUNY, Albany, NY 12222, USA
| | - J Andrew Berglund
- The RNA Institute, University at Albany-SUNY, Albany, NY 12222, USA.
- Center for NeuroGenetics and Biochemistry & Molecular Biology, University of Florida, Gainesville, FL 32608, USA.
| |
Collapse
|
76
|
Lee KY, Chang HC, Seah C, Lee LJ. Deprivation of Muscleblind-Like Proteins Causes Deficits in Cortical Neuron Distribution and Morphological Changes in Dendritic Spines and Postsynaptic Densities. Front Neuroanat 2019; 13:75. [PMID: 31417371 PMCID: PMC6682673 DOI: 10.3389/fnana.2019.00075] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 07/11/2019] [Indexed: 02/06/2023] Open
Abstract
Myotonic dystrophy (Dystrophia Myotonica; DM) is the most common adult-onset muscular dystrophy and its brain symptoms seriously affect patients’ quality of life. It is caused by extended (CTG)n expansions at 3′-UTR of DMPK gene (DM type 1, DM1) or (CCTG)n repeats in the intron 1 of CNBP gene (DM type 2, DM2) and the sequestration of Muscleblind-like (MBNL) family proteins by transcribed (CUG)n RNA hairpin is the main pathogenic mechanism for DM. The MBNL proteins are splicing factors regulating posttranscriptional RNA during development. Previously, Mbnl knockout (KO) mouse lines showed molecular and phenotypic evidence that recapitulate DM brains, however, detailed morphological study has not yet been accomplished. In our studies, control (Mbnl1+/+; Mbnl2cond/cond; Nestin-Cre−/−), Mbnl2 conditional KO (2KO, Mbnl1+/+; Mbnl2cond/cond; Nestin-Cre+/−) and Mbnl1/2 double KO (DKO, Mbnl1ΔE3/ΔE3; Mbnl2cond/cond; Nestin-Cre+/−) mice were generated by crossing three individual lines. Immunohistochemistry for evaluating density and distribution of cortical neurons; Golgi staining for depicting the dendrites/dendritic spines; and electron microscopy for analyzing postsynaptic ultrastructure were performed. We found distributional defects in cortical neurons, reduction in dendritic complexity, immature dendritic spines and alterations of postsynaptic densities (PSDs) in the mutants. In conclusion, loss of function of Mbnl1/2 caused fundamental defects affecting neuronal distribution, dendritic morphology and postsynaptic architectures that are reminiscent of predominantly immature and fetal phenotypes in DM patients.
Collapse
Affiliation(s)
- Kuang-Yung Lee
- Department of Neurology, Chang Gung Memorial Hospital, Keelung, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Ho-Ching Chang
- Graduate Institute of Anatomy and Cell Biology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Carol Seah
- Department of Neurology, Chang Gung Memorial Hospital, Keelung, Taiwan
| | - Li-Jen Lee
- Graduate Institute of Anatomy and Cell Biology, College of Medicine, National Taiwan University, Taipei, Taiwan.,Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan.,Neurobiology and Cognitive Science Center, National Taiwan University, Taipei, Taiwan
| |
Collapse
|
77
|
Sznajder ŁJ, Swanson MS. Short Tandem Repeat Expansions and RNA-Mediated Pathogenesis in Myotonic Dystrophy. Int J Mol Sci 2019; 20:ijms20133365. [PMID: 31323950 PMCID: PMC6651174 DOI: 10.3390/ijms20133365] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 06/27/2019] [Accepted: 07/08/2019] [Indexed: 12/23/2022] Open
Abstract
Short tandem repeat (STR) or microsatellite, expansions underlie more than 50 hereditary neurological, neuromuscular and other diseases, including myotonic dystrophy types 1 (DM1) and 2 (DM2). Current disease models for DM1 and DM2 propose a common pathomechanism, whereby the transcription of mutant DMPK (DM1) and CNBP (DM2) genes results in the synthesis of CUG and CCUG repeat expansion (CUGexp, CCUGexp) RNAs, respectively. These CUGexp and CCUGexp RNAs are toxic since they promote the assembly of ribonucleoprotein (RNP) complexes or RNA foci, leading to sequestration of Muscleblind-like (MBNL) proteins in the nucleus and global dysregulation of the processing, localization and stability of MBNL target RNAs. STR expansion RNAs also form phase-separated gel-like droplets both in vitro and in transiently transfected cells, implicating RNA-RNA multivalent interactions as drivers of RNA foci formation. Importantly, the nucleation and growth of these nuclear foci and transcript misprocessing are reversible processes and thus amenable to therapeutic intervention. In this review, we provide an overview of potential DM1 and DM2 pathomechanisms, followed by a discussion of MBNL functions in RNA processing and how multivalent interactions between expanded STR RNAs and RNA-binding proteins (RBPs) promote RNA foci assembly.
Collapse
Affiliation(s)
- Łukasz J Sznajder
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL 32610, USA.
| | - Maurice S Swanson
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL 32610, USA
| |
Collapse
|
78
|
Banez-Coronel M, Ranum LPW. Repeat-associated non-AUG (RAN) translation: insights from pathology. J Transl Med 2019; 99:929-942. [PMID: 30918326 PMCID: PMC7219275 DOI: 10.1038/s41374-019-0241-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 01/29/2019] [Indexed: 12/14/2022] Open
Abstract
More than 40 different neurological diseases are caused by microsatellite repeat expansions. Since the discovery of repeat-associated non-AUG (RAN) translation by Zu et al. in 2011, nine expansion disorders have been identified as RAN-positive diseases. RAN proteins are translated from different types of nucleotide repeat expansions and can be produced from both sense and antisense transcripts. In some diseases, RAN proteins have been shown to accumulate in affected brain regions. Here we review the pathological and molecular aspects associated with RAN protein accumulation for each particular disorder, the correlation between disease pathology and the available in vivo models and the common aspects shared by some of the newly discovered RAN proteins.
Collapse
Affiliation(s)
- Monica Banez-Coronel
- Center for NeuroGenetics, University of Florida, Gainesville, FL, 32610, USA
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, 32610, USA
| | - Laura P W Ranum
- Center for NeuroGenetics, University of Florida, Gainesville, FL, 32610, USA.
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, 32610, USA.
- Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.
- McKnight Brain Institute, University of Florida, Gainesville, FL, 32610, USA.
- Genetics Institute, University of Florida, Gainesville, FL, 32610, USA.
| |
Collapse
|
79
|
Furuta N, Tsukagoshi S, Hirayanagi K, Ikeda Y. Suppression of the yeast elongation factor Spt4 ortholog reduces expanded SCA36 GGCCUG repeat aggregation and cytotoxicity. Brain Res 2019; 1711:29-40. [DOI: 10.1016/j.brainres.2018.12.045] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 12/28/2018] [Accepted: 12/31/2018] [Indexed: 12/18/2022]
|
80
|
Nguyen L, Cleary JD, Ranum LPW. Repeat-Associated Non-ATG Translation: Molecular Mechanisms and Contribution to Neurological Disease. Annu Rev Neurosci 2019; 42:227-247. [PMID: 30909783 DOI: 10.1146/annurev-neuro-070918-050405] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Microsatellite mutations involving the expansion of tri-, tetra-, penta-, or hexanucleotide repeats cause more than 40 different neurological disorders. Although, traditionally, the position of the repeat within or outside of an open reading frame has been used to focus research on disease mechanisms involving protein loss of function, protein gain of function, or RNA gain of function, the discoveries of bidirectional transcription and repeat-associated non-ATG (RAN) have blurred these distinctions. Here we review what is known about RAN proteins in disease, the mechanisms by which they are produced, and the novel therapeutic opportunities they provide.
Collapse
Affiliation(s)
- Lien Nguyen
- Center for NeuroGenetics, Department of Molecular Genetics and Microbiology, Genetics Institute, and McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610, USA;
| | - John Douglas Cleary
- Center for NeuroGenetics, Department of Molecular Genetics and Microbiology, Genetics Institute, and McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610, USA;
| | - Laura P W Ranum
- Center for NeuroGenetics, Department of Molecular Genetics and Microbiology, Genetics Institute, and McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610, USA;
| |
Collapse
|
81
|
Kim EY, Barefield DY, Vo AH, Gacita AM, Schuster EJ, Wyatt EJ, Davis JL, Dong B, Sun C, Page P, Dellefave-Castillo L, Demonbreun A, Zhang HF, McNally EM. Distinct pathological signatures in human cellular models of myotonic dystrophy subtypes. JCI Insight 2019; 4:122686. [PMID: 30730308 DOI: 10.1172/jci.insight.122686] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 01/31/2019] [Indexed: 01/06/2023] Open
Abstract
Myotonic dystrophy (DM) is the most common autosomal dominant muscular dystrophy and encompasses both skeletal muscle and cardiac complications. DM is nucleotide repeat expansion disorder in which type 1 (DM1) is due to a trinucleotide repeat expansion on chromosome 19 and type 2 (DM2) arises from a tetranucleotide repeat expansion on chromosome 3. Developing representative models of DM in animals has been challenging due to instability of nucleotide repeat expansions, especially for DM2, which is characterized by nucleotide repeat expansions often greater than 5,000 copies. To investigate mechanisms of human DM, we generated cellular models of DM1 and DM2. We used regulated MyoD expression to reprogram urine-derived cells into myotubes. In this myogenic cell model, we found impaired dystrophin expression, in the presence of muscleblind-like 1 (MBNL1) foci, and aberrant splicing in DM1 but not in DM2 cells. We generated induced pluripotent stem cells (iPSC) from healthy controls and DM1 and DM2 subjects, and we differentiated these into cardiomyocytes. DM1 and DM2 cells displayed an increase in RNA foci concomitant with cellular differentiation. iPSC-derived cardiomyocytes from DM1 but not DM2 had aberrant splicing of known target genes and MBNL sequestration. High-resolution imaging revealed tight association between MBNL clusters and RNA foci in DM1. Ca2+ transients differed between DM1- and DM2 iPSC-derived cardiomyocytes, and each differed from healthy control cells. RNA-sequencing from DM1- and DM2 iPSC-derived cardiomyocytes revealed distinct misregulation of gene expression, as well as differential aberrant splicing patterns. Together, these data support that DM1 and DM2, despite some shared clinical and molecular features, have distinct pathological signatures.
Collapse
Affiliation(s)
- Ellis Y Kim
- Molecular Pathogenesis and Molecular Medicine, The University of Chicago, Chicago, Illinois, USA
| | - David Y Barefield
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Andy H Vo
- Committee on Development, Regeneration, and Stem Cell Biology, The University of Chicago, Chicago, Illinois, USA
| | - Anthony M Gacita
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Emma J Schuster
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Eugene J Wyatt
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | | | - Biqin Dong
- Department of Biomedical Engineering and.,Department of Mechanical Engineering, Northwestern University, Evanston, Illinois, USA
| | - Cheng Sun
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois, USA
| | - Patrick Page
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Lisa Dellefave-Castillo
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Alexis Demonbreun
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | | | - Elizabeth M McNally
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| |
Collapse
|
82
|
Soragni E, Petrosyan L, Rinkoski TA, Wieben ED, Baratz KH, Fautsch MP, Gottesfeld JM. Repeat-Associated Non-ATG (RAN) Translation in Fuchs' Endothelial Corneal Dystrophy. Invest Ophthalmol Vis Sci 2019; 59:1888-1896. [PMID: 29677349 PMCID: PMC5886103 DOI: 10.1167/iovs.17-23265] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Purpose The strongest genetic association with Fuchs' endothelial corneal dystrophy (FECD) is the presence of an intronic (CTG·CAG)n trinucleotide repeat (TNR) expansion in the transcription factor 4 (TCF4) gene. Repeat-associated non-ATG (RAN) translation, an unconventional protein translation mechanism that does not require an initiating ATG, has been described in many TNR expansion diseases, including myotonic dystrophy type 1 (DM1). Given the similarities between DM1 and FECD, we wished to determine whether RAN translation occurs in FECD. Methods Antibodies against peptides in the C-terminus of putative RAN translation products from TCF4 were raised and validated by Western blotting and immunofluorescence (IF). CTG·CAG repeats of various lengths in the context of the TCF4 gene were cloned in frame with a 3× FLAG tag and transfected in human cells. IF with antipeptide and anti-FLAG antibodies, as well as cytotoxicity and cell proliferation assays, were performed in these transfected cells. Corneal endothelium derived from patients with FECD was probed with validated antibodies by IF. Results CTG·CAG repeats in the context of the TCF4 gene are transcribed and translated via non-ATG initiation in transfected cells and confer toxicity to an immortalized corneal endothelial cell line. An antipeptide antibody raised against the C-terminus of the TCF4 poly-cysteine frame recognized RAN translation products by IF in cells transfected with CTG·CAG repeats and in FECD corneal endothelium. Conclusions Expanded CTG·CAG repeats in the context of the third intron of TCF4 are transcribed and translated via non-ATG initiation, providing evidence for RAN translation in corneal endothelium of patients with FECD.
Collapse
Affiliation(s)
- Elisabetta Soragni
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, United States
| | - Lina Petrosyan
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, United States
| | - Tommy A Rinkoski
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States
| | - Eric D Wieben
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, United States
| | - Keith H Baratz
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States
| | - Michael P Fautsch
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States
| | - Joel M Gottesfeld
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, United States
| |
Collapse
|
83
|
Repeat-Associated Non-ATG Translation in Neurological Diseases. Cold Spring Harb Perspect Biol 2018; 10:cshperspect.a033019. [PMID: 29891563 DOI: 10.1101/cshperspect.a033019] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
More than 40 different neurological diseases are caused by microsatellite repeat expansions that locate within translated or untranslated gene regions, including 5' and 3' untranslated regions (UTRs), introns, and protein-coding regions. Expansion mutations are transcribed bidirectionally and have been shown to give rise to proteins, which are synthesized from three reading frames in the absence of an AUG initiation codon through a novel process called repeat-associated non-ATG (RAN) translation. RAN proteins, which were first described in spinocerebellar ataxia type 8 (SCA8) and myotonic dystrophy type 1 (DM1), have now been reported in a growing list of microsatellite expansion diseases. This article reviews what is currently known about RAN proteins in microsatellite expansion diseases and experiments that provide clues on how RAN translation is regulated.
Collapse
|
84
|
Wang Y, Hao L, Wang H, Santostefano K, Thapa A, Cleary J, Li H, Guo X, Terada N, Ashizawa T, Xia G. Therapeutic Genome Editing for Myotonic Dystrophy Type 1 Using CRISPR/Cas9. Mol Ther 2018; 26:2617-2630. [PMID: 30274788 PMCID: PMC6225032 DOI: 10.1016/j.ymthe.2018.09.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 08/30/2018] [Accepted: 09/06/2018] [Indexed: 12/18/2022] Open
Abstract
Myotonic dystrophy type 1 (DM1) is caused by a CTG nucleotide repeat expansion within the 3' UTR of the Dystrophia Myotonica protein kinase gene. In this study, we explored therapeutic genome editing using CRISPR/Cas9 via targeted deletion of expanded CTG repeats and targeted insertion of polyadenylation signals in the 3' UTR upstream of the CTG repeats to eliminate toxic RNA CUG repeats. We found paired SpCas9 or SaCas9 guide RNA induced deletion of expanded CTG repeats. However, this approach incurred frequent inversion in both the mutant and normal alleles. In contrast, the insertion of polyadenylation signals in the 3' UTR upstream of the CTG repeats eliminated toxic RNA CUG repeats, which led to phenotype reversal in differentiated neural stem cells, forebrain neurons, cardiomyocytes, and skeletal muscle myofibers. We concluded that targeted insertion of polyadenylation signals in the 3' UTR is a viable approach to develop therapeutic genome editing for DM1.
Collapse
Affiliation(s)
- Yanlin Wang
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Henan 450000, China
| | - Lei Hao
- Department of Neurology, The Fifth People's Hospital of Chongqing, Chongqing 400062, China
| | - Hongcai Wang
- Department of Neurology, Affiliated Hospital of Binzhou Medical University, Binzhou City, Shandong Province, China; Department of Neurology, University of New Mexico, Albuquerque, NM, USA
| | - Katherine Santostefano
- Department of Pathology, Immunology & Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Arjun Thapa
- Department of Neurology, University of New Mexico, Albuquerque, NM, USA
| | - John Cleary
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, USA
| | - Hui Li
- Department of Neurology, University of Wisconsin, Madison, WI, USA
| | - Xiuming Guo
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
| | - Naohiro Terada
- Department of Pathology, Immunology & Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Tetsuo Ashizawa
- Houston Methodist Neurological Institute and Research Institute, 6670 Bertner Ave. R11-117, Houston, TX, USA
| | - Guangbin Xia
- Department of Neurology, University of New Mexico, Albuquerque, NM, USA; Department of Neuroscience, University of New Mexico, Albuquerque, NM, USA.
| |
Collapse
|
85
|
Abstract
Microsatellite expansions cause more than 40 neurological disorders, including Huntington's disease, myotonic dystrophy, and C9ORF72 amyotrophic lateral sclerosis/frontotemporal dementia (ALS/FTD). These repeat expansion mutations can produce repeat-associated non-ATG (RAN) proteins in all three reading frames, which accumulate in disease-relevant tissues. There has been considerable interest in RAN protein products and their downstream consequences, particularly for the dipeptide proteins found in C9ORF72 ALS/FTD. Understanding how RAN translation occurs, what cellular factors contribute to RAN protein accumulation, and how these proteins contribute to disease should lead to a better understanding of the basic mechanisms of gene expression and human disease.
Collapse
Affiliation(s)
- John Douglas Cleary
- From the Center for NeuroGenetics
- Departments of Molecular Genetics and Microbiology and
- Genetics Institute, and
| | - Amrutha Pattamatta
- From the Center for NeuroGenetics
- Departments of Molecular Genetics and Microbiology and
- Genetics Institute, and
| | - Laura P W Ranum
- From the Center for NeuroGenetics,
- Departments of Molecular Genetics and Microbiology and
- Genetics Institute, and
- Neurology, College of Medicine
- McKnight Brain Institute, University of Florida, Gainesville, Florida 32610
| |
Collapse
|
86
|
Abstract
Myotonic dystrophy is an autosomal dominant muscular dystrophy not only associated with muscle weakness, atrophy, and myotonia but also prominent multisystem involvement. There are 2 similar, but distinct, forms of myotonic dystrophy; type 1 is caused by a CTG repeat expansion in the DMPK gene, and type 2 is caused by a CCTG repeat expansion in the CNBP gene. Type 1 is associated with distal limb, neck flexor, and bulbar weakness and results in different phenotypic subtypes with variable onset from congenital to very late-onset as well as variable signs and symptoms. The classically described adult-onset form is the most common. In contrast, myotonic dystrophy type 2 is adult-onset or late-onset, has proximal predominant muscle weakness, and generally has less severe multisystem involvement. In both forms of myotonic dystrophy, the best characterized disease mechanism is a RNA toxic gain-of-function during which RNA repeats form nuclear foci resulting in sequestration of RNA-binding proteins and, therefore, dysregulated splicing of premessenger RNA. There are currently no disease-modifying therapies, but clinical surveillance, preventative measures, and supportive treatments are used to reduce the impact of muscular impairment and other systemic involvement including cataracts, cardiac conduction abnormalities, fatigue, central nervous system dysfunction, respiratory weakness, dysphagia, and endocrine dysfunction. Exciting preclinical progress has been made in identifying a number of potential strategies including genome editing, small molecule therapeutics, and antisense oligonucleotide-based therapies to target the pathogenesis of type 1 and type 2 myotonic dystrophies at the DNA, RNA, or downstream target level.
Collapse
Affiliation(s)
- Samantha LoRusso
- Department of Neurology, The Ohio State University, 395 West 12th Avenue, Columbus, OH, 43210, USA
| | - Benjamin Weiner
- The Ohio State University College of Medicine, The Ohio State University, 370 West 9th Avenue, Columbus, OH, 43210, USA
| | - W David Arnold
- Department of Neurology, The Ohio State University, 395 West 12th Avenue, Columbus, OH, 43210, USA.
| |
Collapse
|
87
|
Ayhan F, Perez BA, Shorrock HK, Zu T, Banez-Coronel M, Reid T, Furuya H, Clark HB, Troncoso JC, Ross CA, Subramony SH, Ashizawa T, Wang ET, Yachnis AT, Ranum LP. SCA8 RAN polySer protein preferentially accumulates in white matter regions and is regulated by eIF3F. EMBO J 2018; 37:embj.201899023. [PMID: 30206144 DOI: 10.15252/embj.201899023] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 07/31/2018] [Accepted: 08/02/2018] [Indexed: 12/12/2022] Open
Abstract
Spinocerebellar ataxia type 8 (SCA8) is caused by a bidirectionally transcribed CTG·CAG expansion that results in the in vivo accumulation of CUG RNA foci, an ATG-initiated polyGln and a polyAla protein expressed by repeat-associated non-ATG (RAN) translation. Although RAN proteins have been reported in a growing number of diseases, the mechanisms and role of RAN translation in disease are poorly understood. We report a novel toxic SCA8 polySer protein which accumulates in white matter (WM) regions as aggregates that increase with age and disease severity. WM regions with polySer aggregates show demyelination and axonal degeneration in SCA8 human and mouse brains. Additionally, knockdown of the eukaryotic translation initiation factor eIF3F in cells reduces steady-state levels of SCA8 polySer and other RAN proteins. Taken together, these data show polySer and WM abnormalities contribute to SCA8 and identify eIF3F as a novel modulator of RAN protein accumulation.
Collapse
Affiliation(s)
- Fatma Ayhan
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Barbara A Perez
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Hannah K Shorrock
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Tao Zu
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Monica Banez-Coronel
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Tammy Reid
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Hirokazu Furuya
- Department of Neurology, Kochi Medical School, Kochi University, Kochi, Japan.,Department of Neurology, Neuro-Muscular Center, NHO Omuta Hospital, Fukuoka, Japan
| | - H Brent Clark
- Department of Laboratory Medicine and Pathology, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Juan C Troncoso
- Department of Pathology and Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Christopher A Ross
- Department of Psychiatry, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Pharmacology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Huntington's Disease Center, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - S H Subramony
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Tetsuo Ashizawa
- Department of Neurology, Houston Methodist Hospital, Houston, TX, USA
| | - Eric T Wang
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Anthony T Yachnis
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Laura Pw Ranum
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA .,Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA.,Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA.,Genetics Institute, University of Florida, Gainesville, FL, USA
| |
Collapse
|
88
|
Glineburg MR, Todd PK, Charlet-Berguerand N, Sellier C. Repeat-associated non-AUG (RAN) translation and other molecular mechanisms in Fragile X Tremor Ataxia Syndrome. Brain Res 2018; 1693:43-54. [PMID: 29453961 PMCID: PMC6010627 DOI: 10.1016/j.brainres.2018.02.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 01/31/2018] [Accepted: 02/02/2018] [Indexed: 11/11/2022]
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset inherited neurodegenerative disorder characterized by progressive intention tremor, gait ataxia and dementia associated with mild brain atrophy. The cause of FXTAS is a premutation expansion, of 55 to 200 CGG repeats localized within the 5'UTR of FMR1. These repeats are transcribed in the sense and antisense directions into mutants RNAs, which have increased expression in FXTAS. Furthermore, CGG sense and CCG antisense expanded repeats are translated into novel proteins despite their localization in putatively non-coding regions of the transcript. Here we focus on two proposed disease mechanisms for FXTAS: 1) RNA gain-of-function, whereby the mutant RNAs bind specific proteins and preclude their normal functions, and 2) repeat-associated non-AUG (RAN) translation, whereby translation through the CGG or CCG repeats leads to the production of toxic homopolypeptides, which in turn interfere with a variety of cellular functions. Here, we analyze the data generated to date on both of these potential molecular mechanisms and lay out a path forward for determining which factors drive FXTAS pathogenicity.
Collapse
Affiliation(s)
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA; Veteran's Affairs Medical Center, Ann Arbor, MI 48105, USA
| | - Nicolas Charlet-Berguerand
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France
| | - Chantal Sellier
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France.
| |
Collapse
|
89
|
Tank EM, Figueroa-Romero C, Hinder LM, Bedi K, Archbold HC, Li X, Weskamp K, Safren N, Paez-Colasante X, Pacut C, Thumma S, Paulsen MT, Guo K, Hur J, Ljungman M, Feldman EL, Barmada SJ. Abnormal RNA stability in amyotrophic lateral sclerosis. Nat Commun 2018; 9:2845. [PMID: 30030424 PMCID: PMC6054632 DOI: 10.1038/s41467-018-05049-z] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 06/11/2018] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) share key features, including accumulation of the RNA-binding protein TDP-43. TDP-43 regulates RNA homeostasis, but it remains unclear whether RNA stability is affected in these disorders. We use Bru-seq and BruChase-seq to assess genome-wide RNA stability in ALS patient-derived cells, demonstrating profound destabilization of ribosomal and mitochondrial transcripts. This pattern is recapitulated by TDP-43 overexpression, suggesting a primary role for TDP-43 in RNA destabilization, and in postmortem samples from ALS and FTD patients. Proteomics and functional studies illustrate corresponding reductions in mitochondrial components and compensatory increases in protein synthesis. Collectively, these observations suggest that TDP-43 deposition leads to targeted RNA instability in ALS and FTD, and may ultimately cause cell death by disrupting energy production and protein synthesis pathways.
Collapse
Affiliation(s)
- E M Tank
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - C Figueroa-Romero
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - L M Hinder
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - K Bedi
- Department of Radiation Oncology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - H C Archbold
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - X Li
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - K Weskamp
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - N Safren
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - X Paez-Colasante
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - C Pacut
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - S Thumma
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - M T Paulsen
- Department of Radiation Oncology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - K Guo
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58202, USA
| | - J Hur
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58202, USA
| | - M Ljungman
- Department of Radiation Oncology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
- Cellular & Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - E L Feldman
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
- Cellular & Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - S J Barmada
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA.
- Cellular & Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI, 48109, USA.
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI, 48109, USA.
| |
Collapse
|
90
|
Braz SO, Acquaire J, Gourdon G, Gomes-Pereira M. Of Mice and Men: Advances in the Understanding of Neuromuscular Aspects of Myotonic Dystrophy. Front Neurol 2018; 9:519. [PMID: 30050493 PMCID: PMC6050950 DOI: 10.3389/fneur.2018.00519] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Accepted: 06/12/2018] [Indexed: 12/26/2022] Open
Abstract
Intensive effort has been directed toward the modeling of myotonic dystrophy (DM) in mice, in order to reproduce human disease and to provide useful tools to investigate molecular and cellular pathogenesis and test efficient therapies. Mouse models have contributed to dissect the multifaceted impact of the DM mutation in various tissues, cell types and in a pleiotropy of pathways, through the expression of toxic RNA transcripts. Changes in alternative splicing, transcription, translation, intracellular RNA localization, polyadenylation, miRNA metabolism and phosphorylation of disease intermediates have been described in different tissues. Some of these events have been directly associated with specific disease symptoms in the skeletal muscle and heart of mice, offering the molecular explanation for individual disease phenotypes. In the central nervous system (CNS), however, the situation is more complex. We still do not know how the molecular abnormalities described translate into CNS dysfunction, nor do we know if the correction of individual molecular events will provide significant therapeutic benefits. The variability in model design and phenotypes described so far requires a thorough and critical analysis. In this review we discuss the recent contributions of mouse models to the understanding of neuromuscular aspects of disease, therapy development, and we provide a reflective assessment of our current limitations and pressing questions that remain unanswered.
Collapse
Affiliation(s)
- Sandra O Braz
- Laboratory CTGDM, INSERM UMR1163, Paris, France.,Institut Imagine, Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Julien Acquaire
- Laboratory CTGDM, INSERM UMR1163, Paris, France.,Institut Imagine, Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Geneviève Gourdon
- Laboratory CTGDM, INSERM UMR1163, Paris, France.,Institut Imagine, Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Mário Gomes-Pereira
- Laboratory CTGDM, INSERM UMR1163, Paris, France.,Institut Imagine, Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| |
Collapse
|
91
|
Rudich P, Lamitina T. Models and mechanisms of repeat expansion disorders: a worm's eye view. J Genet 2018; 97:665-677. [PMID: 30027902 PMCID: PMC6482835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The inappropriate genetic expansion of various repetitive DNA sequences underlies over 20 distinct inherited diseases. The genetic context of these repeats in exons, introns and untranslated regions has played a major role in thinking about the mechanisms by which various repeat expansions might cause disease. Repeat expansions in exons are thought to give rise to expanded toxic protein repeats (i.e. polyQ). Repeat expansions in introns and UTRs (i.e. FXTAS) are thought to produce aberrant repeat-bearing RNAs that interact with and sequester a wide variety of essential proteins, resulting in cellular toxicity. However, a new phenomenon termed 'repeat-associated nonAUG dependent (RAN) translation' paints a new and unifying picture of how distinct repeat expansion-bearing RNAs might act as substrates for this noncanonical form of translation, leading to the production of a wide range of repeat sequence-specific-encoded toxic proteins. Here, we review how the model system Caenorhabditis elegans has been utilized to model many repeat disorders and discuss how RAN translation could be a previously unappreciated contributor to the toxicity associated with these different models.
Collapse
Affiliation(s)
- Paige Rudich
- Graduate Program in Cell Biology and Molecular Physiology, University of Pittsburgh Medical Center, Pittsburgh, PA 15224, USA.
| | | |
Collapse
|
92
|
André LM, Ausems CRM, Wansink DG, Wieringa B. Abnormalities in Skeletal Muscle Myogenesis, Growth, and Regeneration in Myotonic Dystrophy. Front Neurol 2018; 9:368. [PMID: 29892259 PMCID: PMC5985300 DOI: 10.3389/fneur.2018.00368] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 05/07/2018] [Indexed: 12/16/2022] Open
Abstract
Myotonic dystrophy type 1 (DM1) and 2 (DM2) are autosomal dominant degenerative neuromuscular disorders characterized by progressive skeletal muscle weakness, atrophy, and myotonia with progeroid features. Although both DM1 and DM2 are characterized by skeletal muscle dysfunction and also share other clinical features, the diseases differ in the muscle groups that are affected. In DM1, distal muscles are mainly affected, whereas in DM2 problems are mostly found in proximal muscles. In addition, manifestation in DM1 is generally more severe, with possible congenital or childhood-onset of disease and prominent CNS involvement. DM1 and DM2 are caused by expansion of (CTG•CAG)n and (CCTG•CAGG)n repeats in the 3' non-coding region of DMPK and in intron 1 of CNBP, respectively, and in overlapping antisense genes. This critical review will focus on the pleiotropic problems that occur during development, growth, regeneration, and aging of skeletal muscle in patients who inherited these expansions. The current best-accepted idea is that most muscle symptoms can be explained by pathomechanistic effects of repeat expansion on RNA-mediated pathways. However, aberrations in DNA replication and transcription of the DM loci or in protein translation and proteome homeostasis could also affect the control of proliferation and differentiation of muscle progenitor cells or the maintenance and physiological integrity of muscle fibers during a patient's lifetime. Here, we will discuss these molecular and cellular processes and summarize current knowledge about the role of embryonic and adult muscle-resident stem cells in growth, homeostasis, regeneration, and premature aging of healthy and diseased muscle tissue. Of particular interest is that also progenitor cells from extramuscular sources, such as pericytes and mesoangioblasts, can participate in myogenic differentiation. We will examine the potential of all these types of cells in the application of regenerative medicine for muscular dystrophies and evaluate new possibilities for their use in future therapy of DM.
Collapse
Affiliation(s)
- Laurène M André
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - C Rosanne M Ausems
- Department of Genetics, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, Netherlands
| | - Derick G Wansink
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Bé Wieringa
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| |
Collapse
|
93
|
Sellier C, Cerro-Herreros E, Blatter M, Freyermuth F, Gaucherot A, Ruffenach F, Sarkar P, Puymirat J, Udd B, Day JW, Meola G, Bassez G, Fujimura H, Takahashi MP, Schoser B, Furling D, Artero R, Allain FHT, Llamusi B, Charlet-Berguerand N. rbFOX1/MBNL1 competition for CCUG RNA repeats binding contributes to myotonic dystrophy type 1/type 2 differences. Nat Commun 2018; 9:2009. [PMID: 29789616 PMCID: PMC5964235 DOI: 10.1038/s41467-018-04370-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 04/26/2018] [Indexed: 12/30/2022] Open
Abstract
Myotonic dystrophy type 1 and type 2 (DM1, DM2) are caused by expansions of CTG and CCTG repeats, respectively. RNAs containing expanded CUG or CCUG repeats interfere with the metabolism of other RNAs through titration of the Muscleblind-like (MBNL) RNA binding proteins. DM2 follows a more favorable clinical course than DM1, suggesting that specific modifiers may modulate DM severity. Here, we report that the rbFOX1 RNA binding protein binds to expanded CCUG RNA repeats, but not to expanded CUG RNA repeats. Interestingly, rbFOX1 competes with MBNL1 for binding to CCUG expanded repeats and overexpression of rbFOX1 partly releases MBNL1 from sequestration within CCUG RNA foci in DM2 muscle cells. Furthermore, expression of rbFOX1 corrects alternative splicing alterations and rescues muscle atrophy, climbing and flying defects caused by expression of expanded CCUG repeats in a Drosophila model of DM2.
Collapse
Affiliation(s)
- Chantal Sellier
- IGBMC, INSERM U964, CNRS UMR7104, University of Strasbourg, 67404, Illkirch, France
| | - Estefanía Cerro-Herreros
- Translational Genomics Group, Interdisciplinary Research Structure for Biotechnology and Biomedicine BIOTECMED, University of Valencia, 46010, Valencia, Spain
- INCLIVA Health Research Institute, 46010, Valencia, Spain
| | - Markus Blatter
- Institute for Molecular Biology and Biophysics, Swiss Federal Institute of Technology (ETH) Zurich, 8092, Zurich, Switzerland
| | - Fernande Freyermuth
- IGBMC, INSERM U964, CNRS UMR7104, University of Strasbourg, 67404, Illkirch, France
| | - Angeline Gaucherot
- IGBMC, INSERM U964, CNRS UMR7104, University of Strasbourg, 67404, Illkirch, France
| | - Frank Ruffenach
- IGBMC, INSERM U964, CNRS UMR7104, University of Strasbourg, 67404, Illkirch, France
| | - Partha Sarkar
- Department of Neurology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Jack Puymirat
- Human Genetics Research Unit, Laval University, CHUQ, Ste-Foy, Quebec, QC G1V 4G2, Canada
| | - Bjarne Udd
- Neuromuscular Research Center, Tampere University Hospital, 33521, Tampere, Finland
- Department of Medical Genetics, Folkhälsan Institute of Genetics, Helsinki University, 00290, Helsinki, Finland
- Department of Neurology, Vasa Central Hospital, 65130, Vaasa, Finland
| | - John W Day
- Department of Neurology, Stanford University, San Francisco, CA, 94305, USA
| | - Giovanni Meola
- Department of Biomedical Sciences for Health, University of Milan, 20097, Milan, Italy
- Neurology Unit, IRCCS Policlinico San Donato, San Donato Milanese, 20097, Milan, Italy
| | - Guillaume Bassez
- Sorbonne Université, Inserm, Association Institut de Myologie, Center of Research in Myology, 75013, Paris, France
| | - Harutoshi Fujimura
- Department of Neurology, Toneyama National Hospital, Toyonaka, 560-0045, Japan
| | - Masanori P Takahashi
- Department of Neurology, Osaka University Graduate School of Medicine, Suita, 565-0871, Japan
| | - Benedikt Schoser
- Friedrich-Baur-Institute, Department of Neurology, Ludwig Maximilian University, 80539, Munich, Germany
| | - Denis Furling
- Sorbonne Université, Inserm, Association Institut de Myologie, Center of Research in Myology, 75013, Paris, France
| | - Ruben Artero
- Translational Genomics Group, Interdisciplinary Research Structure for Biotechnology and Biomedicine BIOTECMED, University of Valencia, 46010, Valencia, Spain
- INCLIVA Health Research Institute, 46010, Valencia, Spain
| | - Frédéric H T Allain
- Institute for Molecular Biology and Biophysics, Swiss Federal Institute of Technology (ETH) Zurich, 8092, Zurich, Switzerland
| | - Beatriz Llamusi
- Translational Genomics Group, Interdisciplinary Research Structure for Biotechnology and Biomedicine BIOTECMED, University of Valencia, 46010, Valencia, Spain.
- INCLIVA Health Research Institute, 46010, Valencia, Spain.
| | - Nicolas Charlet-Berguerand
- IGBMC, INSERM U964, CNRS UMR7104, University of Strasbourg, 67404, Illkirch, France.
- UMR7104, Centre National de la Recherche Scientifique, 67404, Illkirch, France.
- Institut National de la Santé et de la Recherche Médicale, U964, 67404, Illkirch, France.
- Université de Strasbourg, 67404, Illkirch, France.
| |
Collapse
|
94
|
Moon SL, Sonenberg N, Parker R. Neuronal Regulation of eIF2α Function in Health and Neurological Disorders. Trends Mol Med 2018; 24:575-589. [PMID: 29716790 DOI: 10.1016/j.molmed.2018.04.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 04/04/2018] [Accepted: 04/05/2018] [Indexed: 12/12/2022]
Abstract
A key site of translation control is the phosphorylation of the eukaryotic translation initiation factor 2α (eIF2α), which reduces the rate of GDP to GTP exchange by eIF2B, leading to altered translation. The extent of eIF2α phosphorylation within neurons can alter synaptic plasticity. Phosphorylation of eIF2α is triggered by four stress-responsive kinases, and as such eIF2α is often phosphorylated during neurological perturbations or disease. Moreover, in some cases decreasing eIF2α phosphorylation mitigates neurodegeneration, suggesting that this could be a therapeutic target. Mutations in the γ subunit of eIF2, the guanine exchange factor eIF2B, an eIF2α phosphatase, or in two eIF2α kinases can cause disease in humans, demonstrating the importance of proper regulation of eIF2α phosphorylation for health.
Collapse
Affiliation(s)
- Stephanie L Moon
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80303, USA
| | - Nahum Sonenberg
- Department of Biochemistry and Goodman Cancer Research Centre, McGill University, Montreal, QC H3A 1A3, Canada
| | - Roy Parker
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80303, USA; Howard Hughes Medical Institute, University of Colorado, Boulder, CO 80303, USA.
| |
Collapse
|
95
|
Intron retention induced by microsatellite expansions as a disease biomarker. Proc Natl Acad Sci U S A 2018; 115:4234-4239. [PMID: 29610297 DOI: 10.1073/pnas.1716617115] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Expansions of simple sequence repeats, or microsatellites, have been linked to ∼30 neurological-neuromuscular diseases. While these expansions occur in coding and noncoding regions, microsatellite sequence and repeat length diversity is more prominent in introns with eight different trinucleotide to hexanucleotide repeats, causing hereditary diseases such as myotonic dystrophy type 2 (DM2), Fuchs endothelial corneal dystrophy (FECD), and C9orf72 amyotrophic lateral sclerosis and frontotemporal dementia (C9-ALS/FTD). Here, we test the hypothesis that these GC-rich intronic microsatellite expansions selectively trigger host intron retention (IR). Using DM2, FECD, and C9-ALS/FTD as examples, we demonstrate that retention is readily detectable in affected tissues and peripheral blood lymphocytes and conclude that IR screening constitutes a rapid and inexpensive biomarker for intronic repeat expansion disease.
Collapse
|
96
|
Zeitlberger A, Ging H, Nethisinghe S, Giunti P. Advances in the understanding of hereditary ataxia – implications for future patients. Expert Opin Orphan Drugs 2018. [DOI: 10.1080/21678707.2018.1444477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Anna Zeitlberger
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Heather Ging
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Suran Nethisinghe
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Paola Giunti
- Department of Molecular Neuroscience, UCL, Institute of Neurology, National Hospital for Neurology and Neurosurgery, London, UK
| |
Collapse
|
97
|
Abstract
Accumulating evidence suggests that many classes of DNA repeats exhibit attributes that distinguish them from other genetic variants, including the fact that they are more liable to mutation; this enables them to mediate genetic plasticity. The expansion of tandem repeats, particularly of short tandem repeats, can cause a range of disorders (including Huntington disease, various ataxias, motor neuron disease, frontotemporal dementia, fragile X syndrome and other neurological disorders), and emerging data suggest that tandem repeat polymorphisms (TRPs) can also regulate gene expression in healthy individuals. TRPs in human genomes may also contribute to the missing heritability of polygenic disorders. A better understanding of tandem repeats and their associated repeatome, as well as their capacity for genetic plasticity via both germline and somatic mutations, is needed to transform our understanding of the role of TRPs in health and disease.
Collapse
Affiliation(s)
- Anthony J Hannan
- Florey Institute of Neuroscience and Mental Health, University of Melbourne.,Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Victoria, Australia
| |
Collapse
|
98
|
CUG initiation and frameshifting enable production of dipeptide repeat proteins from ALS/FTD C9ORF72 transcripts. Nat Commun 2018; 9:152. [PMID: 29323119 PMCID: PMC5764992 DOI: 10.1038/s41467-017-02643-5] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 12/14/2017] [Indexed: 12/12/2022] Open
Abstract
Expansion of G4C2 repeats in the C9ORF72 gene is the most prevalent inherited form of amyotrophic lateral sclerosis and frontotemporal dementia. Expanded transcripts undergo repeat-associated non-AUG (RAN) translation producing dipeptide repeat proteins from all reading frames. We determined cis-factors and trans-factors influencing translation of the human C9ORF72 transcripts. G4C2 translation operates through a 5′–3′ cap-dependent scanning mechanism, requiring a CUG codon located upstream of the repeats and an initiator Met-tRNAMeti. Production of poly-GA, poly-GP, and poly-GR proteins from the three frames is influenced by mutation of the same CUG start codon supporting a frameshifting mechanism. RAN translation is also regulated by an upstream open reading frame (uORF) present in mis-spliced C9ORF72 transcripts. Inhibitors of the pre-initiation ribosomal complex and RNA antisense oligonucleotides selectively targeting the 5′-flanking G4C2 sequence block ribosomal scanning and prevent translation. Finally, we identified an unexpected affinity of expanded transcripts for the ribosomal subunits independently from translation. Repeat-associated non-AUG (RAN) translation contributes to the pathogenic mechanism of several microsatellite expansion diseases. Here the authors delineate the different steps involved in recruiting the ribosome to initiate G4C2 RAN translation to produce poly-Glycine Alanine, poly-Glycine Proline, and poly-Glycine Arginine repeats.
Collapse
|
99
|
Cheng W, Wang S, Mestre AA, Fu C, Makarem A, Xian F, Hayes LR, Lopez-Gonzalez R, Drenner K, Jiang J, Cleveland DW, Sun S. C9ORF72 GGGGCC repeat-associated non-AUG translation is upregulated by stress through eIF2α phosphorylation. Nat Commun 2018; 9:51. [PMID: 29302060 PMCID: PMC5754368 DOI: 10.1038/s41467-017-02495-z] [Citation(s) in RCA: 148] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 12/01/2017] [Indexed: 01/04/2023] Open
Abstract
Hexanucleotide repeat expansion in C9ORF72 is the most frequent cause of both amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Here we demonstrate that the repeat-associated non-AUG (RAN) translation of (GGGGCC) n -containing RNAs into poly-dipeptides can initiate in vivo without a 5'-cap. The primary RNA substrate for RAN translation of C9ORF72 sense repeats is shown to be the spliced first intron, following its excision from the initial pre-mRNA and transport to the cytoplasm. Cap-independent RAN translation is shown to be upregulated by various stress stimuli through phosphorylation of the α subunit of eukaryotic initiation factor-2 (eIF2α), the core event of an integrated stress response (ISR). Compounds inhibiting phospho-eIF2α-signaling pathways are shown to suppress RAN translation. Since the poly-dipeptides can themselves induce stress, these findings support a feedforward loop with initial repeat-mediated toxicity enhancing RAN translation and subsequent production of additional poly-dipeptides through ISR, thereby promoting progressive disease.
Collapse
Affiliation(s)
- Weiwei Cheng
- Department of Pathology and Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Shaopeng Wang
- Department of Pathology and Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Alexander A Mestre
- Department of Pathology and Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Chenglai Fu
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Andres Makarem
- Department of Pathology and Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Fengfan Xian
- Department of Pathology and Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Lindsey R Hayes
- Brain Science Institute and Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Rodrigo Lopez-Gonzalez
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Kevin Drenner
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, 92093, USA
| | - Jie Jiang
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, 92093, USA
| | - Don W Cleveland
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, 92093, USA
| | - Shuying Sun
- Department of Pathology and Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
| |
Collapse
|
100
|
Abstract
Ribonucleic acid (RNA) homeostasis is dynamically modulated in response to changing physiological conditions. Tight regulation of RNA abundance through both transcription and degradation determines the amount, timing, and location of protein translation. This balance is of particular importance in neurons, which are among the most metabolically active and morphologically complex cells in the body. As a result, any disruptions in RNA degradation can have dramatic consequences for neuronal health. In this chapter, we will first discuss mechanisms of RNA stabilization and decay. We will then explore how the disruption of these pathways can lead to neurodegenerative disease.
Collapse
|