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Moissoglu K, Wang T, Gasparski AN, Stueland M, Paine EL, Jenkins L, Mili S. A KIF1C-CNBP motor-adaptor complex for trafficking mRNAs to cell protrusions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.26.600878. [PMID: 38979199 PMCID: PMC11230373 DOI: 10.1101/2024.06.26.600878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
mRNA localization to subcellular compartments is a widely used mechanism that functionally contributes to numerous processes. mRNA targeting can be achieved upon recognition of RNA cargo by molecular motors. However, our molecular understanding of how this is accomplished is limited, especially in higher organisms. We focus on a pathway that targets mRNAs to peripheral protrusions of mammalian cells and is important for cell migration. Trafficking occurs through active transport on microtubules, mediated by the KIF1C kinesin. Here, we identify the RNA-binding protein CNBP, as a factor required for mRNA localization to protrusions. CNBP binds directly to GA-rich sequences in the 3'UTR of protrusion targeted mRNAs. CNBP also interacts with KIF1C and is required for KIF1C recruitment to mRNAs and for their trafficking on microtubules to the periphery. This work provides a molecular mechanism for KIF1C recruitment to mRNA cargo and reveals a motor-adaptor complex for mRNA transport to cell protrusions.
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2
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Marzullo M, Coni S, De Simone A, Canettieri G, Ciapponi L. Modeling Myotonic Dystrophy Type 2 Using Drosophila melanogaster. Int J Mol Sci 2023; 24:14182. [PMID: 37762484 PMCID: PMC10532015 DOI: 10.3390/ijms241814182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 09/04/2023] [Accepted: 09/13/2023] [Indexed: 09/29/2023] Open
Abstract
Myotonic dystrophy 2 (DM2) is a genetic multi-systemic disease primarily affecting skeletal muscle. It is caused by CCTGn expansion in intron 1 of the CNBP gene, which encodes a zinc finger protein. DM2 disease has been successfully modeled in Drosophila melanogaster, allowing the identification and validation of new pathogenic mechanisms and potential therapeutic strategies. Here, we describe the principal tools used in Drosophila to study and dissect molecular pathways related to muscular dystrophies and summarize the main findings in DM2 pathogenesis based on DM2 Drosophila models. We also illustrate how Drosophila may be successfully used to generate a tractable animal model to identify novel genes able to affect and/or modify the pathogenic pathway and to discover new potential drugs.
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Affiliation(s)
- Marta Marzullo
- Department of Biology and Biotechnologies “C. Darwin”, Sapienza University of Rome, 00185 Rome, Italy; (M.M.)
| | - Sonia Coni
- Department of Molecular Medicine, Sapienza University of Rome, 00161 Rome, Italy
| | - Assia De Simone
- Department of Biology and Biotechnologies “C. Darwin”, Sapienza University of Rome, 00185 Rome, Italy; (M.M.)
| | - Gianluca Canettieri
- Department of Molecular Medicine, Sapienza University of Rome, 00161 Rome, Italy
- Istituto Pasteur Italia, Fondazione Cenci Bolognetti, 00161 Rome, Italy
| | - Laura Ciapponi
- Department of Biology and Biotechnologies “C. Darwin”, Sapienza University of Rome, 00185 Rome, Italy; (M.M.)
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3
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Development of Therapeutic Approaches for Myotonic Dystrophies Type 1 and Type 2. Int J Mol Sci 2022; 23:ijms231810491. [PMID: 36142405 PMCID: PMC9499601 DOI: 10.3390/ijms231810491] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 09/06/2022] [Accepted: 09/07/2022] [Indexed: 11/17/2022] Open
Abstract
Myotonic Dystrophies type 1 (DM1) and type 2 (DM2) are complex multisystem diseases without disease-based therapies. These disorders are caused by the expansions of unstable CTG (DM1) and CCTG (DM2) repeats outside of the coding regions of the disease genes: DMPK in DM1 and CNBP in DM2. Multiple clinical and molecular studies provided a consensus for DM1 pathogenesis, showing that the molecular pathophysiology of DM1 is associated with the toxicity of RNA CUG repeats, which cause multiple disturbances in RNA metabolism in patients' cells. As a result, splicing, translation, RNA stability and transcription of multiple genes are misregulated in DM1 cells. While mutant CCUG repeats are the main cause of DM2, additional factors might play a role in DM2 pathogenesis. This review describes current progress in the translation of mechanistic knowledge in DM1 and DM2 to clinical trials, with a focus on the development of disease-specific therapies for patients with adult forms of DM1 and congenital DM1 (CDM1).
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4
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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.
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5
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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: 1.0] [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.
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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
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6
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Armas P, Coux G, Weiner AMJ, Calcaterra NB. What's new about CNBP? Divergent functions and activities for a conserved nucleic acid binding protein. Biochim Biophys Acta Gen Subj 2021; 1865:129996. [PMID: 34474118 DOI: 10.1016/j.bbagen.2021.129996] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 08/26/2021] [Indexed: 12/21/2022]
Abstract
BACKGROUND Cellular nucleic acid binding protein (CNBP) is a conserved single-stranded nucleic acid binding protein present in most eukaryotes, but not in plants. Expansions in the CNBP gene cause myotonic dystrophy type 2. Initially reported as a transcriptional regulator, CNBP was then also identified acting as a translational regulator. SCOPE OF REVIEW The focus of this review was to link the CNBP structural features and newly reported biochemical activities with the recently described biological functions, in the context of its pathological significance. MAJOR CONCLUSIONS Several post-translational modifications affect CNBP subcellular localization and activity. CNBP participates in the transcriptional and translational regulation of a wide range of genes by remodeling single-stranded nucleic acid secondary structures and/or by modulating the activity of trans-acting factors. CNBP is required for proper neural crest and heart development, and plays a role in cell proliferation control. Besides, CNBP has been linked with neurodegenerative, inflammatory, and congenital diseases, as well as with tumor processes. GENERAL SIGNIFICANCE This review provides an insight into the growing functions of CNBP in cell biology. A unique and robust mechanistic or biochemical connection among these roles has yet not been elucidated. However, the ability of CNBP to dynamically integrate signaling pathways and to act as nucleic acid chaperone may explain most of the roles and functions identified so far.
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Affiliation(s)
- Pablo Armas
- Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONIeCET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Esmeralda y Ocampo 531, S2002LRK Rosario, Argentina
| | - Gabriela Coux
- Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONIeCET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Esmeralda y Ocampo 531, S2002LRK Rosario, Argentina
| | - Andrea M J Weiner
- Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONIeCET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Esmeralda y Ocampo 531, S2002LRK Rosario, Argentina
| | - Nora B Calcaterra
- Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONIeCET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Esmeralda y Ocampo 531, S2002LRK Rosario, Argentina.
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7
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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: 3] [Impact Index Per Article: 1.0] [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.
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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
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8
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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: 9] [Impact Index Per Article: 2.3] [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.
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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;
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9
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Braems E, Swinnen B, Van Den Bosch L. C9orf72 loss-of-function: a trivial, stand-alone or additive mechanism in C9 ALS/FTD? Acta Neuropathol 2020; 140:625-643. [PMID: 32876811 PMCID: PMC7547039 DOI: 10.1007/s00401-020-02214-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 07/28/2020] [Accepted: 08/13/2020] [Indexed: 12/11/2022]
Abstract
A repeat expansion in C9orf72 is responsible for the characteristic neurodegeneration in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) in a still unresolved manner. Proposed mechanisms involve gain-of-functions, comprising RNA and protein toxicity, and loss-of-function of the C9orf72 gene. Their exact contribution is still inconclusive and reports regarding loss-of-function are rather inconsistent. Here, we review the function of the C9orf72 protein and its relevance in disease. We explore the potential link between reduced C9orf72 levels and disease phenotypes in postmortem, in vitro, and in vivo models. Moreover, the significance of loss-of-function in other non-coding repeat expansion diseases is used to clarify its contribution in C9orf72 ALS/FTD. In conclusion, with evidence pointing to a multiple-hit model, loss-of-function on itself seems to be insufficient to cause neurodegeneration in C9orf72 ALS/FTD.
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Affiliation(s)
- Elke Braems
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven-University of Leuven, 3000, Leuven, Belgium
- Laboratory of Neurobiology, Experimental Neurology, Center for Brain and Disease Research, VIB, Campus Gasthuisberg, O&N4, Herestraat 49, PB 602, 3000, Leuven, Belgium
| | - Bart Swinnen
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven-University of Leuven, 3000, Leuven, Belgium
- Laboratory of Neurobiology, Experimental Neurology, Center for Brain and Disease Research, VIB, Campus Gasthuisberg, O&N4, Herestraat 49, PB 602, 3000, Leuven, Belgium
- Department of Neurology, University Hospitals Leuven, 3000, Leuven, Belgium
| | - Ludo Van Den Bosch
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven-University of Leuven, 3000, Leuven, Belgium.
- Laboratory of Neurobiology, Experimental Neurology, Center for Brain and Disease Research, VIB, Campus Gasthuisberg, O&N4, Herestraat 49, PB 602, 3000, Leuven, Belgium.
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10
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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: 40] [Impact Index Per Article: 10.0] [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.
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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.
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11
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Stepniak-Konieczna E, Konieczny P, Cywoniuk P, Dluzewska J, Sobczak K. AON-induced splice-switching and DMPK pre-mRNA degradation as potential therapeutic approaches for Myotonic Dystrophy type 1. Nucleic Acids Res 2020; 48:2531-2543. [PMID: 31965181 PMCID: PMC7049696 DOI: 10.1093/nar/gkaa007] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 12/28/2019] [Accepted: 01/03/2020] [Indexed: 01/04/2023] Open
Abstract
Expansion of an unstable CTG repeat in the 3′UTR of the DMPK gene causes Myotonic Dystrophy type 1 (DM1). CUG-expanded DMPK transcripts (CUGexp) sequester Muscleblind-like (MBNL) alternative splicing regulators in ribonuclear inclusions (foci), leading to abnormalities in RNA processing and splicing. To alleviate the burden of CUGexp, we tested therapeutic approach utilizing antisense oligonucleotides (AONs)-mediated DMPK splice-switching and degradation of mutated pre-mRNA. Experimental design involved: (i) skipping of selected constitutive exons to induce frameshifting and decay of toxic mRNAs by an RNA surveillance mechanism, and (ii) exclusion of the alternative exon 15 (e15) carrying CUGexp from DMPK mRNA. While first strategy failed to stimulate DMPK mRNA decay, exclusion of e15 enhanced DMPK nuclear export but triggered accumulation of potentially harmful spliced out pre-mRNA fragment containing CUGexp. Neutralization of this fragment with antisense gapmers complementary to intronic sequences preceding e15 failed to diminish DM1-specific spliceopathy due to AONs’ chemistry-related toxicity. However, intronic gapmers alone reduced the level of DMPK mRNA and mitigated DM1-related cellular phenotypes including spliceopathy and nuclear foci. Thus, a combination of the correct chemistry and experimental approach should be carefully considered to design a safe AON-based therapeutic strategy for DM1.
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Affiliation(s)
- Ewa Stepniak-Konieczna
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University in Poznan, Uniwersytetu Poznanskiego 6, 61-614 Poznan, Poland
| | - Patryk Konieczny
- Institute of Human Biology and Evolution, Faculty of Biology, Adam Mickiewicz University in Poznan, Uniwersytetu Poznanskiego 6, 61-614 Poznan, Poland
| | - Piotr Cywoniuk
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University in Poznan, Uniwersytetu Poznanskiego 6, 61-614 Poznan, Poland
| | - Julia Dluzewska
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University in Poznan, Uniwersytetu Poznanskiego 6, 61-614 Poznan, Poland
| | - Krzysztof Sobczak
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University in Poznan, Uniwersytetu Poznanskiego 6, 61-614 Poznan, Poland
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12
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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: 10.4] [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.
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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
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13
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Chen Y, Sharma S, Assis PA, Jiang Z, Elling R, Olive AJ, Hang S, Bernier J, Huh JR, Sassetti CM, Knipe DM, Gazzinelli RT, Fitzgerald KA. CNBP controls IL-12 gene transcription and Th1 immunity. J Exp Med 2018; 215:3136-3150. [PMID: 30442645 PMCID: PMC6279399 DOI: 10.1084/jem.20181031] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 09/05/2018] [Accepted: 10/23/2018] [Indexed: 12/22/2022] Open
Abstract
These studies reveal a previously unrecognized role for Cnbp as a novel transcriptional regulator engaged downstream of innate immune receptors controlling the c-Rel–IL-12–Th1 axis, which has important implications for both host defense and inflammatory disease. An inducible program of inflammatory gene expression is a hallmark of antimicrobial defenses. Recently, cellular nucleic acid–binding protein (CNBP) was identified as a regulator of nuclear factor-kappaB (NF-κB)–dependent proinflammatory cytokine gene expression. Here, we generated mice lacking CNBP and found that CNBP regulates a very restricted gene signature that includes IL-12β. CNBP resides in the cytosol of macrophages and translocates to the nucleus in response to diverse microbial pathogens and pathogen-derived products. Cnbp-deficient macrophages induced canonical NF-κB/Rel signaling normally but were impaired in their ability to control the activation of c-Rel, a key driver of IL-12β gene transcription. The nuclear translocation and DNA-binding activity of c-Rel required CNBP. Lastly, Cnbp-deficient mice were more susceptible to acute toxoplasmosis associated with reduced production of IL-12β, as well as a reduced T helper type 1 (Th1) cell IFN-γ response essential to controlling parasite replication. Collectively, these findings identify CNBP as important regulator of c-Rel–dependent IL-12β gene transcription and Th1 immunity.
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Affiliation(s)
- Yongzhi Chen
- Program in Innate Immunity, Department of Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Shruti Sharma
- Program in Innate Immunity, Department of Medicine, University of Massachusetts Medical School, Worcester, MA.,Department of Immunology, Tufts University School of Medicine, Boston, MA
| | - Patricia A Assis
- Program in Innate Immunity, Department of Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Zhaozhao Jiang
- Program in Innate Immunity, Department of Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Roland Elling
- Program in Innate Immunity, Department of Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Andrew J Olive
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA
| | - Saiyu Hang
- Division of Immunology, Department of Microbiology and Immunology, Harvard Medical School, Boston, MA
| | - Jennifer Bernier
- Program in Innate Immunity, Department of Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Jun R Huh
- Division of Immunology, Department of Microbiology and Immunology, Harvard Medical School, Boston, MA
| | - Christopher M Sassetti
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA
| | - David M Knipe
- Department of Microbiology and Immunology, Harvard Medical School, Boston, MA
| | - Ricardo T Gazzinelli
- Program in Innate Immunity, Department of Medicine, University of Massachusetts Medical School, Worcester, MA.,Departamento de Bioquímica e Imunologia, Universidade Federal of Minas Gerais, Belo Horizonte, Brazil.,Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Brazil
| | - Katherine A Fitzgerald
- Program in Innate Immunity, Department of Medicine, University of Massachusetts Medical School, Worcester, MA .,Centre for Molecular Inflammation Research, Department of Cancer Research and Molecular Medicine, Trondheim, Norway
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14
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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.
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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.
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15
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Reduction of Cellular Nucleic Acid Binding Protein Encoded by a Myotonic Dystrophy Type 2 Gene Causes Muscle Atrophy. Mol Cell Biol 2018; 38:MCB.00649-17. [PMID: 29735719 DOI: 10.1128/mcb.00649-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 04/26/2018] [Indexed: 12/17/2022] Open
Abstract
Myotonic dystrophy type 2 (DM2) is a neuromuscular disease caused by an expansion of intronic CCTG repeats in the CNBP gene, which encodes a protein regulating translation and transcription. To better understand the role of cellular nucleic acid binding protein (CNBP) in DM2 pathology, we examined skeletal muscle in a new model of Cnbp knockout (KO) mice. This study showed that a loss of Cnbp disturbs myofibrillar sarcomeric organization at birth. Surviving homozygous Cnbp KO mice develop muscle atrophy at a young age. The skeletal muscle phenotype in heterozygous Cnbp KO mice was milder, but they developed severe muscle wasting at an advanced age. Several proteins that control global translation and muscle contraction are altered in muscle of Cnbp KO mice. A search for CNBP binding proteins showed that CNBP interacts with the α subunit of the dystroglycan complex, a core component of the multimeric dystrophin-glycoprotein complex, which regulates membrane stability. Whereas CNBP is reduced in cytoplasm of DM2 human fibers, it is a predominantly membrane protein in DM2 fibers, and its interaction with α-dystroglycan is increased in DM2. These findings suggest that alterations of CNBP in DM2 might cause muscle atrophy via CNBP-mediated translation and via protein-protein interactions affecting myofiber membrane function.
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16
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Sulek A, Lusakowska A, Krysa W, Rajkiewicz M, Kaminska A, Nojszewska M, Kostera-Pruszczyk A, Zdzienicka E, Kubalska J, Rakowicz M, Szirkowiec W, Kwiecinski H, Zaremba J. WITHDRAWN: Evidence for a relatively high proportion of DM2 mutations in a large group of Polish patients. Neurol Neurochir Pol 2018:S0028-3843(18)30152-X. [PMID: 29880430 DOI: 10.1016/j.pjnns.2018.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 04/12/2018] [Indexed: 11/24/2022]
Abstract
The Publisher regrets that this article is an accidental duplication of an article that has already been published, 10.1016/j.pjnns.2018.02.008. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.
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Affiliation(s)
- Anna Sulek
- Department of Genetics, Institute of Psychiatry and Neurology, Warsaw, Poland.
| | | | - Wioletta Krysa
- Department of Genetics, Institute of Psychiatry and Neurology, Warsaw, Poland
| | - Marta Rajkiewicz
- Department of Genetics, Institute of Psychiatry and Neurology, Warsaw, Poland
| | - Anna Kaminska
- Department of Neurology, Medical University, Warsaw, Poland
| | | | | | - Elzbieta Zdzienicka
- Department of Genetics, Institute of Psychiatry and Neurology, Warsaw, Poland
| | - Jolanta Kubalska
- Department of Genetics, Institute of Psychiatry and Neurology, Warsaw, Poland
| | - Maria Rakowicz
- Department of Clinical Neurophysiology, Institute of Psychiatry and Neurology, Warsaw, Poland
| | | | | | - Jacek Zaremba
- Department of Genetics, Institute of Psychiatry and Neurology, Warsaw, Poland
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17
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Baltaci AK, Yuce K, Mogulkoc R. Zinc Metabolism and Metallothioneins. Biol Trace Elem Res 2018; 183:22-31. [PMID: 28812260 DOI: 10.1007/s12011-017-1119-7] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 08/02/2017] [Indexed: 12/20/2022]
Abstract
Among the trace elements, zinc is one of the most used elements in biological systems. Zinc is found in the structure of more than 2700 enzymes, including hydrolases, transferases, oxyreductases, ligases, isomerases, and lyases. Not surprisingly, it is present in almost all body cells. Preserving the stability and integrity of biological membranes and ion channels, zinc is also an intracellular regulator and provides structural support to proteins during molecular interactions. It acts as a structural element in nucleic acids or other gene-regulating proteins. Metallothioneins, the low molecular weight protein family rich in cysteine groups, are involved significantly in numerous physiological and pathological processes including particularly oxidative stress. A critical role of metallothioneins (MT) is to bind zinc with high affinity and to serve as an intracellular zinc reservoir. By releasing free intracellular zinc when needed, MTs mediate the unique physiological roles of zinc. MT expression is induced by zinc elevation, and thus, zinc homeostasis is maintained. That MT mediates the effects of zinc, besides having strong radical scavenging effects, points to the critical part it plays in oxidative stress. The present review aims to give information on metallothioneins, which have critical importance in the metabolism and molecular pathways of zinc.
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Affiliation(s)
| | - Kemal Yuce
- Department of Physiology, Medical Faculty, Selcuk University, Konya, Turkey
| | - Rasim Mogulkoc
- Department of Physiology, Medical Faculty, Selcuk University, Konya, Turkey
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18
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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: 13.7] [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.
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19
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Sulek A, Lusakowska A, Krysa W, Rajkiewicz M, Kaminska A, Nojszewska M, Kostera-Pruszczyk A, Zdzienicka E, Kubalska J, Rakowicz M, Szirkowiec W, Kwiecinski H, Zaremba J. Evidence for a relatively high proportion of DM2 mutations in a large group of Polish patients. Neurol Neurochir Pol 2018; 52:736-742. [PMID: 29588063 DOI: 10.1016/j.pjnns.2018.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 02/16/2018] [Accepted: 02/26/2018] [Indexed: 11/16/2022]
Abstract
INTRODUCTION Myotonic dystrophies (DMs) type 1 (DM1) and type 2 (DM2) are autosomal dominant, multisystem disorders, considered the most common dystrophies in adults. DM1 and DM2 are caused by dynamic mutations in the DMPK and CNBP genes, respectively. METHODS Molecular analyses were performed by PCR and the modified RP-PCR in patients, in their at-risk relatives and prenatal cases. RESULTS The analysis of Polish controls revealed the range of 5-31 CTG repeats for DM1 and 110-228 bp alleles for DM2. Among 318 confirmed probands - 196 (62%) were DM1 and 122 (38%) - DM2. Within DM1families, 10 subjects carried a low expanded CTG tract (< 100 repeats), which resulted in a full mutation in subsequent generations. Two related individuals had unstable alleles-188 bp and 196 bp without common interruptions. CONCLUSION The relative frequencies of DM1/DM2 among Polish patients were 68% and 32%, respectively, with a relatively high proportion of DM2 mutations (1.6:1).
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Affiliation(s)
- Anna Sulek
- Department of Genetics, Institute of Psychiatry and Neurology, Warsaw, Poland.
| | - Anna Lusakowska
- Department of Neurology, Medical University of Warsaw, Warsaw, Poland
| | - Wioletta Krysa
- Department of Genetics, Institute of Psychiatry and Neurology, Warsaw, Poland
| | - Marta Rajkiewicz
- Department of Genetics, Institute of Psychiatry and Neurology, Warsaw, Poland
| | - Anna Kaminska
- Department of Neurology, Medical University of Warsaw, Warsaw, Poland
| | - Monika Nojszewska
- Department of Neurology, Medical University of Warsaw, Warsaw, Poland
| | | | - Elzbieta Zdzienicka
- Department of Genetics, Institute of Psychiatry and Neurology, Warsaw, Poland
| | - Jolanta Kubalska
- Department of Genetics, Institute of Psychiatry and Neurology, Warsaw, Poland
| | - Maria Rakowicz
- Department of Clinical Neurophysiology, Institute of Psychiatry and Neurology, Warsaw, Poland
| | | | - Hubert Kwiecinski
- Department of Neurology, Medical University of Warsaw, Warsaw, Poland
| | - Jacek Zaremba
- Department of Genetics, Institute of Psychiatry and Neurology, Warsaw, Poland
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20
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Thomas JD, Oliveira R, Sznajder ŁJ, Swanson MS. Myotonic Dystrophy and Developmental Regulation of RNA Processing. Compr Physiol 2018; 8:509-553. [PMID: 29687899 PMCID: PMC11323716 DOI: 10.1002/cphy.c170002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Myotonic dystrophy (DM) is a multisystemic disorder caused by microsatellite expansion mutations in two unrelated genes leading to similar, yet distinct, diseases. DM disease presentation is highly variable and distinguished by differences in age-of-onset and symptom severity. In the most severe form, DM presents with congenital onset and profound developmental defects. At the molecular level, DM pathogenesis is characterized by a toxic RNA gain-of-function mechanism that involves the transcription of noncoding microsatellite expansions. These mutant RNAs disrupt key cellular pathways, including RNA processing, localization, and translation. In DM, these toxic RNA effects are predominantly mediated through the modulation of the muscleblind-like and CUGBP and ETR-3-like factor families of RNA binding proteins (RBPs). Dysfunction of these RBPs results in widespread RNA processing defects culminating in the expression of developmentally inappropriate protein isoforms in adult tissues. The tissue that is the focus of this review, skeletal muscle, is particularly sensitive to mutant RNA-responsive perturbations, as patients display a variety of developmental, structural, and functional defects in muscle. Here, we provide a comprehensive overview of DM1 and DM2 clinical presentation and pathology as well as the underlying cellular and molecular defects associated with DM disease onset and progression. Additionally, fundamental aspects of skeletal muscle development altered in DM are highlighted together with ongoing and potential therapeutic avenues to treat this muscular dystrophy. © 2018 American Physiological Society. Compr Physiol 8:509-553, 2018.
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Affiliation(s)
- James D. Thomas
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, Florida, USA
| | - Ruan Oliveira
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, Florida, USA
| | - Łukasz J. Sznajder
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, Florida, USA
| | - Maurice S. Swanson
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, Florida, USA
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21
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Santoro M, Fontana L, Maiorca F, Centofanti F, Massa R, Silvestri G, Novelli G, Botta A. Expanded [CCTG]n repetitions are not associated with abnormal methylation at the CNBP locus in myotonic dystrophy type 2 (DM2) patients. Biochim Biophys Acta Mol Basis Dis 2018; 1864:917-924. [DOI: 10.1016/j.bbadis.2017.12.037] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 12/21/2017] [Accepted: 12/28/2017] [Indexed: 01/10/2023]
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22
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Expanded CCUG repeat RNA expression in Drosophila heart and muscle trigger Myotonic Dystrophy type 1-like phenotypes and activate autophagocytosis genes. Sci Rep 2017; 7:2843. [PMID: 28588248 PMCID: PMC5460254 DOI: 10.1038/s41598-017-02829-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 04/19/2017] [Indexed: 12/12/2022] Open
Abstract
Myotonic dystrophies (DM1–2) are neuromuscular genetic disorders caused by the pathological expansion of untranslated microsatellites. DM1 and DM2, are caused by expanded CTG repeats in the 3′UTR of the DMPK gene and CCTG repeats in the first intron of the CNBP gene, respectively. Mutant RNAs containing expanded repeats are retained in the cell nucleus, where they sequester nuclear factors and cause alterations in RNA metabolism. However, for unknown reasons, DM1 is more severe than DM2. To study the differences and similarities in the pathogenesis of DM1 and DM2, we generated model flies by expressing pure expanded CUG ([250]×) or CCUG ([1100]×) repeats, respectively, and compared them with control flies expressing either 20 repeat units or GFP. We observed surprisingly severe muscle reduction and cardiac dysfunction in CCUG-expressing model flies. The muscle and cardiac tissue of both DM1 and DM2 model flies showed DM1-like phenotypes including overexpression of autophagy-related genes, RNA mis-splicing and repeat RNA aggregation in ribonuclear foci along with the Muscleblind protein. These data reveal, for the first time, that expanded non-coding CCUG repeat-RNA has similar in vivo toxicity potential as expanded CUG RNA in muscle and heart tissues and suggests that specific, as yet unknown factors, quench CCUG-repeat toxicity in DM2 patients.
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23
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Thornton CA, Wang E, Carrell EM. Myotonic dystrophy: approach to therapy. Curr Opin Genet Dev 2017; 44:135-140. [PMID: 28376341 PMCID: PMC5447481 DOI: 10.1016/j.gde.2017.03.007] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 02/25/2017] [Accepted: 03/13/2017] [Indexed: 01/16/2023]
Abstract
Myotonic dystrophy (DM) is a dominantly-inherited genetic disorder affecting skeletal muscle, heart, brain, and other organs. DM type 1 is caused by expansion of a CTG triplet repeat in DMPK, whereas DM type 2 is caused by expansion of a CCTG tetramer repeat in CNBP. In both cases the DM mutations lead to expression of dominant-acting RNAs. Studies of RNA toxicity have now revealed novel mechanisms and new therapeutic targets. Preclinical data have suggested that RNA dominance is responsive to therapeutic intervention and that DM therapy can be approached at several different levels. Here we review recent efforts to alleviate RNA toxicity in DM.
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Affiliation(s)
- Charles A Thornton
- Department of Neurology, University of Rochester, Rochester 14642, NY, United States.
| | - Eric Wang
- Department of Molecular Genetics & Microbiology, Center for NeuroGenetics, University of Florida, Gainesville, FL, United States
| | - Ellie M Carrell
- Department of Neurology, University of Rochester, Rochester 14642, NY, United States
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24
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Biomolecular diagnosis of myotonic dystrophy type 2: a challenging approach. J Neurol 2017; 264:1705-1714. [PMID: 28550479 DOI: 10.1007/s00415-017-8504-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 05/02/2017] [Indexed: 01/23/2023]
Abstract
Myotonic dystrophy type 1 (DM1) and type 2 (DM2) are the most common adult form of muscular dystrophy, characterized by autosomal dominant progressive myopathy, myotonia, and multiorgan involvement. The onset and symptoms of the myotonic dystrophies are diverse, complicating their diagnoses and limiting a comprehensive approach to their clinical care. Diagnostic delay in DM2 is due not only to the heterogeneous phenotype and the aspecific onset but also to the unfamiliarity with the disorder by most clinicians. Moreover, the DM2 diagnostic odyssey is complicated by the difficulties to develop an accurate, robust, and cost-effective method for a routine molecular assay. The aim of this review is to underline by challenging approach the diagnostic limits and pitfalls that could results in failure to recognize the presence of DM2 disease. Understanding and preventing delays in DM2 diagnosis may facilitate family planning, improve symptom management in the short term, and facilitate more specific treatment in the long term.
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Schmacht L, Traber J, Grieben U, Utz W, Dieringer MA, Kellman P, Blaszczyk E, von Knobelsdorff-Brenkenhoff F, Spuler S, Schulz-Menger J. Cardiac Involvement in Myotonic Dystrophy Type 2 Patients With Preserved Ejection Fraction: Detection by Cardiovascular Magnetic Resonance. Circ Cardiovasc Imaging 2017; 9:CIRCIMAGING.115.004615. [PMID: 27363857 DOI: 10.1161/circimaging.115.004615] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 05/24/2016] [Indexed: 12/27/2022]
Abstract
BACKGROUND Myotonic dystrophy type 2 (DM2) is a genetic disorder characterized by skeletal muscle symptoms, metabolic changes, and cardiac involvement. Histopathologic alterations of the skeletal muscle include fibrosis and fatty infiltration. The aim of this study was to investigate whether subclinical cardiac involvement in DM2 is already detectable in preserved left ventricular function by cardiovascular magnetic resonance. METHODS AND RESULTS Twenty-seven patients (mean age, 54±10 years; 20 females) with a genetically confirmed diagnosis of DM2 were compared with 17 healthy age- and sex-matched controls using a 1.5 T magnetic resonance imaging. For myocardial tissue differentiation, T1 and T2 mapping, fat/water-separated imaging, focal fibrosis imaging (late gadolinium enhancement [LGE]), and (1)H magnetic resonance spectroscopy were performed. Extracellular volume fraction was calculated. Conduction abnormalities were diagnosed based on Groh criteria. LGE located subepicardial basal inferolateral was detectable in 22% of the patients. Extracellular volume was increased in this region and in the adjacent medial inferolateral segment (P=0.03 compared with healthy controls). In 21% of patients with DM2, fat deposits were detectable (all women). The control group showed no abnormalities. Myocardial triglycerides were not different in LGE-positive and LGE-negative subjects (P=0.47). Six patients had indicators for conduction disease (60% of LGE-positive patients and 12.5% of LGE-negative patients). CONCLUSIONS In DM2, subclinical myocardial injury was already detectable in preserved left ventricular ejection fraction. Extracellular volume was also increased in regions with no focal fibrosis. Myocardial fibrosis was related to conduction abnormalities.
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Affiliation(s)
- Luisa Schmacht
- From the Working Group on Cardiovascular Magnetic Resonance, Experimental, and Clinical Research Center, a joint cooperation between the Charité University Medicine Berlin and the Max-Delbrueck Center for Molecular Medicine, and HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Germany (L.S., J.T., W.U., M.A.D., E.B., F.v.K.-B., J.S.-M.); DZHK (German Center for Cardiovascular Research), partner site Berlin, Germany (L.S., F.v.K.-B, J.S.-M.); Muscle Research Unit, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine, Berlin, Germany (U.G., S.S.); and Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD (P.K.)
| | - Julius Traber
- From the Working Group on Cardiovascular Magnetic Resonance, Experimental, and Clinical Research Center, a joint cooperation between the Charité University Medicine Berlin and the Max-Delbrueck Center for Molecular Medicine, and HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Germany (L.S., J.T., W.U., M.A.D., E.B., F.v.K.-B., J.S.-M.); DZHK (German Center for Cardiovascular Research), partner site Berlin, Germany (L.S., F.v.K.-B, J.S.-M.); Muscle Research Unit, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine, Berlin, Germany (U.G., S.S.); and Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD (P.K.)
| | - Ulrike Grieben
- From the Working Group on Cardiovascular Magnetic Resonance, Experimental, and Clinical Research Center, a joint cooperation between the Charité University Medicine Berlin and the Max-Delbrueck Center for Molecular Medicine, and HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Germany (L.S., J.T., W.U., M.A.D., E.B., F.v.K.-B., J.S.-M.); DZHK (German Center for Cardiovascular Research), partner site Berlin, Germany (L.S., F.v.K.-B, J.S.-M.); Muscle Research Unit, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine, Berlin, Germany (U.G., S.S.); and Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD (P.K.)
| | - Wolfgang Utz
- From the Working Group on Cardiovascular Magnetic Resonance, Experimental, and Clinical Research Center, a joint cooperation between the Charité University Medicine Berlin and the Max-Delbrueck Center for Molecular Medicine, and HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Germany (L.S., J.T., W.U., M.A.D., E.B., F.v.K.-B., J.S.-M.); DZHK (German Center for Cardiovascular Research), partner site Berlin, Germany (L.S., F.v.K.-B, J.S.-M.); Muscle Research Unit, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine, Berlin, Germany (U.G., S.S.); and Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD (P.K.)
| | - Matthias A Dieringer
- From the Working Group on Cardiovascular Magnetic Resonance, Experimental, and Clinical Research Center, a joint cooperation between the Charité University Medicine Berlin and the Max-Delbrueck Center for Molecular Medicine, and HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Germany (L.S., J.T., W.U., M.A.D., E.B., F.v.K.-B., J.S.-M.); DZHK (German Center for Cardiovascular Research), partner site Berlin, Germany (L.S., F.v.K.-B, J.S.-M.); Muscle Research Unit, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine, Berlin, Germany (U.G., S.S.); and Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD (P.K.)
| | - Peter Kellman
- From the Working Group on Cardiovascular Magnetic Resonance, Experimental, and Clinical Research Center, a joint cooperation between the Charité University Medicine Berlin and the Max-Delbrueck Center for Molecular Medicine, and HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Germany (L.S., J.T., W.U., M.A.D., E.B., F.v.K.-B., J.S.-M.); DZHK (German Center for Cardiovascular Research), partner site Berlin, Germany (L.S., F.v.K.-B, J.S.-M.); Muscle Research Unit, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine, Berlin, Germany (U.G., S.S.); and Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD (P.K.)
| | - Edyta Blaszczyk
- From the Working Group on Cardiovascular Magnetic Resonance, Experimental, and Clinical Research Center, a joint cooperation between the Charité University Medicine Berlin and the Max-Delbrueck Center for Molecular Medicine, and HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Germany (L.S., J.T., W.U., M.A.D., E.B., F.v.K.-B., J.S.-M.); DZHK (German Center for Cardiovascular Research), partner site Berlin, Germany (L.S., F.v.K.-B, J.S.-M.); Muscle Research Unit, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine, Berlin, Germany (U.G., S.S.); and Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD (P.K.)
| | - Florian von Knobelsdorff-Brenkenhoff
- From the Working Group on Cardiovascular Magnetic Resonance, Experimental, and Clinical Research Center, a joint cooperation between the Charité University Medicine Berlin and the Max-Delbrueck Center for Molecular Medicine, and HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Germany (L.S., J.T., W.U., M.A.D., E.B., F.v.K.-B., J.S.-M.); DZHK (German Center for Cardiovascular Research), partner site Berlin, Germany (L.S., F.v.K.-B, J.S.-M.); Muscle Research Unit, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine, Berlin, Germany (U.G., S.S.); and Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD (P.K.)
| | - Simone Spuler
- From the Working Group on Cardiovascular Magnetic Resonance, Experimental, and Clinical Research Center, a joint cooperation between the Charité University Medicine Berlin and the Max-Delbrueck Center for Molecular Medicine, and HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Germany (L.S., J.T., W.U., M.A.D., E.B., F.v.K.-B., J.S.-M.); DZHK (German Center for Cardiovascular Research), partner site Berlin, Germany (L.S., F.v.K.-B, J.S.-M.); Muscle Research Unit, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine, Berlin, Germany (U.G., S.S.); and Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD (P.K.)
| | - Jeanette Schulz-Menger
- From the Working Group on Cardiovascular Magnetic Resonance, Experimental, and Clinical Research Center, a joint cooperation between the Charité University Medicine Berlin and the Max-Delbrueck Center for Molecular Medicine, and HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Germany (L.S., J.T., W.U., M.A.D., E.B., F.v.K.-B., J.S.-M.); DZHK (German Center for Cardiovascular Research), partner site Berlin, Germany (L.S., F.v.K.-B, J.S.-M.); Muscle Research Unit, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine, Berlin, Germany (U.G., S.S.); and Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD (P.K.).
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Meola G, Cardani R. Myotonic dystrophy type 2 and modifier genes: an update on clinical and pathomolecular aspects. Neurol Sci 2017; 38:535-546. [PMID: 28078562 DOI: 10.1007/s10072-016-2805-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Accepted: 12/22/2016] [Indexed: 12/20/2022]
Abstract
Myotonic dystrophy (DM) is the most common adult muscular dystrophy, characterized by autosomal dominant progressive myopathy, myotonia, and multiorgan involvement. To date, two distinct forms caused by similar mutations in two different genes have been identified: myotonic dystrophy type 1 (DM1) and myotonic dystrophy type 2 (DM2). Aberrant transcription and mRNA processing of multiple genes due to RNA-mediated toxic gain-of function has been suggested to cause the complex phenotype in DM1 and DM2. However, despite clinical and genetic similarities, DM1 and DM2 may be considered as distinct disorders. This review is an update on the latest findings specific to DM2, including explanations for the differences in clinical manifestations and pathophysiology between the two forms of myotonic dystrophies.
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Affiliation(s)
- Giovanni Meola
- Department of Biomedical Sciences for Health, University of Milan, IRCCS Policlinico San Donato, Piazza E. Malan, 1, San Donato Mil., 20097, Milan, Italy. .,Department of Neurology, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy.
| | - Rosanna Cardani
- Laboratory of Muscle Histopathology and Molecular Biology, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy
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Massalska D, Zimowski JG, Bijok J, Kucińska-Chahwan A, Łusakowska A, Jakiel G, Roszkowski T. Prenatal diagnosis of congenital myopathies and muscular dystrophies. Clin Genet 2016; 90:199-210. [PMID: 27197572 DOI: 10.1111/cge.12801] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 05/05/2016] [Accepted: 05/08/2016] [Indexed: 12/14/2022]
Abstract
Congenital myopathies and muscular dystrophies constitute a genetically and phenotypically heterogeneous group of rare inherited diseases characterized by muscle weakness and atrophy, motor delay and respiratory insufficiency. To date, curative care is not available for these diseases, which may severely affect both life-span and quality of life. We discuss prenatal diagnosis and genetic counseling for families at risk, as well as diagnostic possibilities in sporadic cases.
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Affiliation(s)
- D Massalska
- Department of Obstetrics and Gynecology, Centre of Postgraduate Medical Education, Warsaw, Poland
| | - J G Zimowski
- Department of Genetics, Institute of Psychiatry and Neurology, Warsaw, Poland
| | - J Bijok
- Department of Obstetrics and Gynecology, Centre of Postgraduate Medical Education, Warsaw, Poland
| | - A Kucińska-Chahwan
- Department of Obstetrics and Gynecology, Centre of Postgraduate Medical Education, Warsaw, Poland
| | - A Łusakowska
- Department of Neurology, Medical University of Warsaw, Poland
| | - G Jakiel
- Department of Obstetrics and Gynecology, Centre of Postgraduate Medical Education, Warsaw, Poland
| | - T Roszkowski
- Department of Obstetrics and Gynecology, Centre of Postgraduate Medical Education, Warsaw, Poland
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Costales MG, Rzuczek SG, Disney MD. Comparison of small molecules and oligonucleotides that target a toxic, non-coding RNA. Bioorg Med Chem Lett 2016; 26:2605-9. [PMID: 27117425 DOI: 10.1016/j.bmcl.2016.04.025] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 04/09/2016] [Accepted: 04/11/2016] [Indexed: 11/29/2022]
Abstract
Potential RNA targets for chemical probes and therapeutic modalities are pervasive in the transcriptome. Oligonucleotide-based therapeutics are commonly used to target RNA sequence. Small molecules are emerging as a modality to target RNA structures selectively, but their development is still in its infancy. In this work, we compare the activity of oligonucleotides and several classes of small molecules that target the non-coding r(CCUG) repeat expansion (r(CCUG)(exp)) that causes myotonic dystrophy type 2 (DM2), an incurable disease that is the second-most common cause of adult onset muscular dystrophy. Small molecule types investigated include monomers, dimers, and multivalent compounds synthesized on-site by using RNA-templated click chemistry. Oligonucleotides investigated include phosphorothioates that cleave their target and vivo-morpholinos that modulate target RNA activity via binding. We show that compounds assembled on-site that recognize structure have the highest potencies amongst small molecules and are similar in potency to a vivo-morpholino modified oligonucleotide that targets sequence. These studies are likely to impact the design of therapeutic modalities targeting other repeats expansions that cause fragile X syndrome and amyotrophic lateral sclerosis, for example.
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Affiliation(s)
- Matthew G Costales
- Departments of Chemistry & Neuroscience, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, United States
| | - Suzanne G Rzuczek
- Departments of Chemistry & Neuroscience, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, United States
| | - Matthew D Disney
- Departments of Chemistry & Neuroscience, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, United States.
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Niblock M, Smith BN, Lee YB, Sardone V, Topp S, Troakes C, Al-Sarraj S, Leblond CS, Dion PA, Rouleau GA, Shaw CE, Gallo JM. Retention of hexanucleotide repeat-containing intron in C9orf72 mRNA: implications for the pathogenesis of ALS/FTD. Acta Neuropathol Commun 2016; 4:18. [PMID: 26916632 PMCID: PMC4766718 DOI: 10.1186/s40478-016-0289-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 02/15/2016] [Indexed: 12/12/2022] Open
Abstract
INTRODUCTION The most common forms of amyotrophic lateral sclerosis and frontotemporal dementia are caused by a large GGGGCC repeat expansion in the first intron of the C9orf72 gene. The repeat-containing intron should be degraded after being spliced out, however GGGGCC repeat-containing RNA species either accumulate in nuclear foci or are exported to the cytoplasm where they are translated into potentially toxic dipeptide repeat proteins by repeat-associated non-AUG-initiated (RAN) translation. RESULTS In order to determine the mechanisms of repeat-containing intron misprocessing, we have analyzed C9orf72 transcripts in lymphoblasts from C9orf72 expansion carriers (n = 15) and control individuals (n = 15). We have identified polyadenylated C9orf72 RNA species retaining the repeat-containing intron and in which downstream exons are spliced correctly resulting in a C9orf72 mRNA with an enlarged 5'-UTR containing the GGGGCC repeats. Intron-retaining transcripts are produced from both wild-type and mutant alleles. Intron-retaining C9orf72 transcripts were also detected in brain with a 2.7 fold increase measured in the frontal cortex from heterozygous expansion carriers (n = 11) compared to controls (n = 10). The level of intron-retaining transcripts was increased 5.9 fold in a case homozygous for the expansion. We also show that a large proportion of intron 1-retaining C9orf72 transcripts accumulate in the nucleus. CONCLUSIONS Retention of the repeat-containing intron in mature C9orf72 mRNA can potentially explain nuclear foci formation as well as nuclear export of GGGGCC repeat RNA and suggests that the misprocessing of C9orf72 transcripts initiates the pathogenic process caused by C9orf72 hexanucleotide repeat expansions as well as provides the basis for novel therapeutic strategies.
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Meola G, Cardani R. Myotonic Dystrophy Type 2: An Update on Clinical Aspects, Genetic and Pathomolecular Mechanism. J Neuromuscul Dis 2015; 2:S59-S71. [PMID: 27858759 PMCID: PMC5240594 DOI: 10.3233/jnd-150088] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Myotonic dystrophy (DM) is the most common adult muscular dystrophy, characterized by autosomal dominant progressive myopathy, myotonia and multiorgan involvement. To date two distinct forms caused by similar mutations have been identified. Myotonic dystrophy type 1 (DM1, Steinert's disease) is caused by a (CTG)n expansion in DMPK, while myotonic dystrophy type 2 (DM2) is caused by a (CCTG)n expansion in CNBP. Despite clinical and genetic similarities, DM1 and DM2 are distinct disorders. The pathogenesis of DM is explained by a common RNA gain-of-function mechanism in which the CUG and CCUG repeats alter cellular function, including alternative splicing of various genes. However additional pathogenic mechanism like changes in gene expression, modifier genes, protein translation and micro-RNA metabolism may also contribute to disease pathology and to clarify the phenotypic differences between these two types of myotonic dystrophies.This review is an update on the latest findings specific to DM2, including explanations for the differences in clinical manifestations and pathophysiology between the two forms of myotonic dystrophies.
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Affiliation(s)
- Giovanni Meola
- Department of Biomedical Sciences for Health, IRCCS Policlinico San Donato, University of Milan, San Donato Milanese, Milan, Italy
- Laboratory of Muscle Histopathology and Molecular Biology, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy
| | - Rosanna Cardani
- Laboratory of Muscle Histopathology and Molecular Biology, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy
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Mateos-Aierdi AJ, Goicoechea M, Aiastui A, Fernández-Torrón R, Garcia-Puga M, Matheu A, López de Munain A. Muscle wasting in myotonic dystrophies: a model of premature aging. Front Aging Neurosci 2015. [PMID: 26217220 PMCID: PMC4496580 DOI: 10.3389/fnagi.2015.00125] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Myotonic dystrophy type 1 (DM1 or Steinert’s disease) and type 2 (DM2) are multisystem disorders of genetic origin. Progressive muscular weakness, atrophy and myotonia are the most prominent neuromuscular features of these diseases, while other clinical manifestations such as cardiomyopathy, insulin resistance and cataracts are also common. From a clinical perspective, most DM symptoms are interpreted as a result of an accelerated aging (cataracts, muscular weakness and atrophy, cognitive decline, metabolic dysfunction, etc.), including an increased risk of developing tumors. From this point of view, DM1 could be described as a progeroid syndrome since a notable age-dependent dysfunction of all systems occurs. The underlying molecular disorder in DM1 consists of the existence of a pathological (CTG) triplet expansion in the 3′ untranslated region (UTR) of the Dystrophia Myotonica Protein Kinase (DMPK) gene, whereas (CCTG)n repeats in the first intron of the Cellular Nucleic acid Binding Protein/Zinc Finger Protein 9(CNBP/ZNF9) gene cause DM2. The expansions are transcribed into (CUG)n and (CCUG)n-containing RNA, respectively, which form secondary structures and sequester RNA-binding proteins, such as the splicing factor muscleblind-like protein (MBNL), forming nuclear aggregates known as foci. Other splicing factors, such as CUGBP, are also disrupted, leading to a spliceopathy of a large number of downstream genes linked to the clinical features of these diseases. Skeletal muscle regeneration relies on muscle progenitor cells, known as satellite cells, which are activated after muscle damage, and which proliferate and differentiate to muscle cells, thus regenerating the damaged tissue. Satellite cell dysfunction seems to be a common feature of both age-dependent muscle degeneration (sarcopenia) and muscle wasting in DM and other muscle degenerative diseases. This review aims to describe the cellular, molecular and macrostructural processes involved in the muscular degeneration seen in DM patients, highlighting the similarities found with muscle aging.
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Affiliation(s)
- Alba Judith Mateos-Aierdi
- Neuroscience Area, Biodonostia Health Research Institute San Sebastián, Spain ; CIBERNED, Instituto Carlos III, Ministerio de Economía y Competitividad Madrid, Spain
| | - Maria Goicoechea
- Neuroscience Area, Biodonostia Health Research Institute San Sebastián, Spain ; CIBERNED, Instituto Carlos III, Ministerio de Economía y Competitividad Madrid, Spain
| | - Ana Aiastui
- CIBERNED, Instituto Carlos III, Ministerio de Economía y Competitividad Madrid, Spain ; Cell Culture Platform, Biodonostia Health Research Institute, San Sebastián Spain
| | - Roberto Fernández-Torrón
- Neuroscience Area, Biodonostia Health Research Institute San Sebastián, Spain ; CIBERNED, Instituto Carlos III, Ministerio de Economía y Competitividad Madrid, Spain ; Department of Neurology, Hospital Universitario Donostia, San Sebastián Spain
| | - Mikel Garcia-Puga
- Oncology Area, Biodonostia Health Research Institute San Sebastián, Spain
| | - Ander Matheu
- Oncology Area, Biodonostia Health Research Institute San Sebastián, Spain
| | - Adolfo López de Munain
- Neuroscience Area, Biodonostia Health Research Institute San Sebastián, Spain ; CIBERNED, Instituto Carlos III, Ministerio de Economía y Competitividad Madrid, Spain ; Department of Neurology, Hospital Universitario Donostia, San Sebastián Spain ; Department of Neuroscience, Universidad del País Vasco UPV-EHU San Sebastián, Spain
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Abstract
Myotonic dystrophy (dystrophia myotonica, DM) is one of the most common lethal monogenic disorders in populations of European descent. DM type 1 was first described over a century ago. More recently, a second form of the disease, DM type 2 was recognized, which results from repeat expansion in a different gene. Both disorders have autosomal dominant inheritance and multisystem features, including myotonic myopathy, cataract, and cardiac conduction disease. This article reviews the clinical presentation and pathophysiology of DM and discusses current management and future potential for developing targeted therapies.
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Affiliation(s)
- Charles A Thornton
- Department of Neurology, Center for Neural Development and Disease, Center for RNA Biology, University of Rochester Medical Center, Box 645, 601 Elmwood Avenue, Rochester, NY 14642, USA.
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Cardani R, Giagnacovo M, Rossi G, Renna LV, Bugiardini E, Pizzamiglio C, Botta A, Meola G. Progression of muscle histopathology but not of spliceopathy in myotonic dystrophy type 2. Neuromuscul Disord 2014; 24:1042-53. [PMID: 25139674 DOI: 10.1016/j.nmd.2014.06.435] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 06/07/2014] [Accepted: 06/17/2014] [Indexed: 12/25/2022]
Abstract
Myotonic dystrophy type 2 (DM2) is an autosomal dominant progressive disease involving skeletal and cardiac muscle and brain. It is caused by a tetranucleotide repeat within the first intron of the CNBP gene that leads to an alteration of the alternative splicing of several genes. To understand the molecular mechanisms that play a role in DM2 progression, the evolution of skeletal muscle histopathology and biomolecular findings in successive biopsies have been studied. Biceps brachii biopsies from 5 DM2 patients who underwent two successive biopsies at different years of age have been used. Muscle histopathology has been assessed on sections immunostained with fast or slow myosin. FISH in combination with MBNL1-immunofluorescence has been performed to evaluate ribonuclear inclusion and MBNL1 foci dimensions in myonuclei. Gene and protein expression and alteration of alternative splicing of several genes have been evaluated over time. All DM2 patients examined show a worsening of muscle histopathology and an increase of foci dimensions over time. The progressive worsening of myotonia in DM2 patients may be due to the decrease of CLCN1 mRNA observed in all patients examined. However, a worsening of alternative splicing alterations has not been evidenced over time. The data obtained in this study confirm that DM2 is a slow progression disease since histological and biomolecular alterations observed in skeletal muscle are minimal even after 10-year interval. The data indicate that muscle morphological alterations evolve more rapidly over time than the molecular changes thus indicating that muscle biopsy is a more sensitive tool than biomolecular markers to assess disease progression at muscle level.
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Affiliation(s)
- Rosanna Cardani
- Laboratory of Muscle Histopathology and Molecular Biology, IRCCS Policlinico San Donato, Milan, Italy
| | - Marzia Giagnacovo
- Department of Biology and Biotechnologies, University of Pavia, Pavia, Italy
| | - Giulia Rossi
- Department of Biomedicine and Prevention, Tor Vergata University of Rome, Rome, Italy
| | - Laura V Renna
- Department of Biosciences, University of Milan, Milan, Italy
| | - Enrico Bugiardini
- Department of Neurology, University of Milan, IRCCS-Policlinico San Donato, Milan, Italy
| | - Chiara Pizzamiglio
- Department of Neurology, University of Milan, IRCCS-Policlinico San Donato, Milan, Italy
| | - Annalisa Botta
- Department of Biomedicine and Prevention, Tor Vergata University of Rome, Rome, Italy
| | - Giovanni Meola
- Laboratory of Muscle Histopathology and Molecular Biology, IRCCS Policlinico San Donato, Milan, Italy; Department of Neurology, University of Milan, IRCCS-Policlinico San Donato, Milan, Italy.
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Nguyen L, Lee J, Wong CH, Zimmerman SC. Small molecules that target the toxic RNA in myotonic dystrophy type 2. ChemMedChem 2014; 9:2455-62. [PMID: 24938413 DOI: 10.1002/cmdc.201402095] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Indexed: 12/19/2022]
Abstract
Myotonic dystrophy type 2 (DM2) is caused by an expansion of CCTG repeats in the zinc-finger protein gene (ZNF9). Transcribed CCUG repeats sequester muscleblind-like protein 1 (MBNL1), an important alternative splicing regulator, preventing its normal function, leading to the disease phenotype. We describe a series of ligands that disrupt the MBNL1-r(CCUG)n interaction as potential lead agents for developing DM2 therapeutics. A previously reported triaminopyrimidine-acridine conjugate was a moderate inhibitor in vitro, however it proved to be poorly water-soluble and not cell-permeable. To improve its therapeutic potential, the new set of ligands maintained the key triaminopyrimidine recognition unit but replaced the acridine intercalator with a bisamidinium groove binder. The optimized ligands exhibit low micromolar inhibition potency to MBNL1-r(CCUG)8. Importantly, the ligands are the first to show the ability to disrupt the MBNL1-r(CCUG)n foci in DM2 model cell culture and exhibit low cytotoxicity.
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Affiliation(s)
- Lien Nguyen
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL 61801 (USA)
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Screen M, Jonson PH, Raheem O, Palmio J, Laaksonen R, Lehtimäki T, Sirito M, Krahe R, Hackman P, Udd B. Abnormal splicing of NEDD4 in myotonic dystrophy type 2: possible link to statin adverse reactions. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:2322-32. [PMID: 24907641 DOI: 10.1016/j.ajpath.2014.04.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 03/19/2014] [Accepted: 04/08/2014] [Indexed: 11/17/2022]
Abstract
Myotonic dystrophy type 2 (DM2) is a multisystemic disorder caused by a (CCTG)n repeat expansion in intron 1 of CNBP. Transcription of the repeats causes a toxic RNA gain of function involving their accumulation in ribonuclear foci. This leads to sequestration of splicing factors and alters pre-mRNA splicing in a range of downstream effector genes, which is thought to contribute to the diverse DM2 clinical features. Hyperlipidemia is frequent in DM2 patients, but the treatment is problematic because of an increased risk of statin-induced adverse reactions. Hypothesizing that shared pathways lead to the increased risk, we compared the skeletal muscle expression profiles of DM2 patients and controls with patients with hyperlipidemia on statin therapy. Neural precursor cell expressed, developmentally downregulated-4 (NEDD4), an ubiquitin ligase, was one of the dysregulated genes identified in DM2 patients and patients with statin-treated hyperlipidemia. In DM2 muscle, NEDD4 mRNA was abnormally spliced, leading to aberrant NEDD4 proteins. NEDD4 was down-regulated in persons taking statins, and simvastatin treatment of C2C12 cells suppressed NEDD4 transcription. Phosphatase and tensin homologue (PTEN), an established NEDD4 target, was increased and accumulated in highly atrophic DM2 muscle fibers. PTEN ubiquitination was reduced in DM2 myofibers, suggesting that the NEDD4-PTEN pathway is dysregulated in DM2 skeletal muscle. Thus, this pathway may contribute to the increased risk of statin-adverse reactions in patients with DM2.
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Affiliation(s)
- Mark Screen
- Folkhälsan Institute of Genetics and Department of Medical Genetics, Haartman Institute, University of Helsinki, Helsinki, Finland
| | - Per Harald Jonson
- Folkhälsan Institute of Genetics and Department of Medical Genetics, Haartman Institute, University of Helsinki, Helsinki, Finland
| | - Olayinka Raheem
- Neuromuscular Research Centre, Department of Neurology, University Hospital and University of Tampere, Tampere, Finland
| | - Johanna Palmio
- Neuromuscular Research Centre, Department of Neurology, University Hospital and University of Tampere, Tampere, Finland
| | - Reijo Laaksonen
- Department of Clinical Chemistry, Fimlab Laboratories, and School of Medicine, University of Tampere, Tampere, Finland
| | - Terho Lehtimäki
- Department of Clinical Chemistry, Fimlab Laboratories, and School of Medicine, University of Tampere, Tampere, Finland
| | - Mario Sirito
- Department of Genetics, the University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Ralf Krahe
- Department of Genetics, the University of Texas MD Anderson Cancer Center, Houston, Texas; Human & Molecular Genetics, Graduate School of Biomedical Sciences, University of Texas at Houston, Houston, Texas; Genes & Development Programs, Graduate School of Biomedical Sciences, University of Texas at Houston, Houston, Texas
| | - Peter Hackman
- Folkhälsan Institute of Genetics and Department of Medical Genetics, Haartman Institute, University of Helsinki, Helsinki, Finland
| | - Bjarne Udd
- Folkhälsan Institute of Genetics and Department of Medical Genetics, Haartman Institute, University of Helsinki, Helsinki, Finland; Neuromuscular Research Centre, Department of Neurology, University Hospital and University of Tampere, Tampere, Finland; Department of Neurology, Vaasa Central Hospital, Vaasa, Finland.
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Meola G, Cardani R. Myotonic dystrophies: An update on clinical aspects, genetic, pathology, and molecular pathomechanisms. Biochim Biophys Acta Mol Basis Dis 2014; 1852:594-606. [PMID: 24882752 DOI: 10.1016/j.bbadis.2014.05.019] [Citation(s) in RCA: 213] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 05/19/2014] [Accepted: 05/20/2014] [Indexed: 01/18/2023]
Abstract
Myotonic dystrophy (DM) is the most common adult muscular dystrophy, characterized by autosomal dominant progressive myopathy, myotonia and multiorgan involvement. To date two distinct forms caused by similar mutations have been identified. Myotonic dystrophy type 1 (DM1, Steinert's disease) is caused by a (CTG)n expansion in DMPK, while myotonic dystrophy type 2 (DM2) is caused by a (CCTG)n expansion in ZNF9/CNBP. When transcribed into CUG/CCUG-containing RNA, mutant transcripts aggregate as nuclear foci that sequester RNA-binding proteins, resulting in spliceopathy of downstream effector genes. However, it is now clear that additional pathogenic mechanism like changes in gene expression, protein translation and micro-RNA metabolism may also contribute to disease pathology. Despite clinical and genetic similarities, DM1 and DM2 are distinct disorders requiring different diagnostic and management strategies. This review is an update on the recent advances in the understanding of the molecular mechanisms behind myotonic dystrophies. This article is part of a Special Issue entitled: Neuromuscular Diseases: Pathology and Molecular Pathogenesis.
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Affiliation(s)
- Giovanni Meola
- Department of Neurology, IRCCS Policlinico San Donato, University of Milan, San Donato Milanese, Milan, Italy; Laboratory of Muscle Histopathology and Molecular Biology, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy.
| | - Rosanna Cardani
- Laboratory of Muscle Histopathology and Molecular Biology, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy.
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Gene expression profiling in tibial muscular dystrophy reveals unfolded protein response and altered autophagy. PLoS One 2014; 9:e90819. [PMID: 24618559 PMCID: PMC3949689 DOI: 10.1371/journal.pone.0090819] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 02/04/2014] [Indexed: 11/19/2022] Open
Abstract
Tibial muscular dystrophy (TMD) is a late onset, autosomal dominant distal myopathy that results from mutations in the two last domains of titin. The cascade of molecular events leading from the causative Titin mutations to the preterm death of muscle cells in TMD is largely unknown. In this study we examined the mRNA and protein changes associated with the myopathology of TMD. To identify these components we performed gene expression profiling using muscle biopsies from TMD patients and healthy controls. The profiling results were confirmed through quantitative real-time PCR and protein level analysis. One of the pathways identified was activation of endoplasmic reticulum (ER) stress response. ER stress activates the unfolded protein response (UPR) pathway. UPR activation was supported by elevation of the marker genes HSPA5, ERN1 and the UPR specific XBP1 splice form. However, UPR activation appears to be insufficient to correct the protein abnormalities causing its activation because degenerative TMD muscle fibres show an increase in ubiquitinated protein inclusions. Abnormalities of VCP-associated degradation pathways are also suggested by the presence of proteolytic VCP fragments in western blotting, and VCP's accumulation within rimmed vacuoles in TMD muscle fibres together with p62 and LC3B positive autophagosomes. Thus, pathways controlling turnover and degradation, including autophagy, are distorted and lead to degeneration and loss of muscle fibres.
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Goodwin M, Swanson MS. RNA-binding protein misregulation in microsatellite expansion disorders. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 825:353-88. [PMID: 25201111 PMCID: PMC4483269 DOI: 10.1007/978-1-4939-1221-6_10] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
RNA-binding proteins (RBPs) play pivotal roles in multiple cellular pathways from transcription to RNA turnover by interacting with RNA sequence and/or structural elements to form distinct RNA-protein complexes. Since these complexes are required for the normal regulation of gene expression, mutations that alter RBP functions may result in a cascade of deleterious events that lead to severe disease. Here, we focus on a group of hereditary disorders, the microsatellite expansion diseases, which alter RBP activities and result in abnormal neurological and neuromuscular phenotypes. While many of these diseases are classified as adult-onset disorders, mounting evidence indicates that disruption of normal RNA-protein interaction networks during embryogenesis modifies developmental pathways, which ultimately leads to disease manifestations later in life. Efforts to understand the molecular basis of these disorders has already uncovered novel pathogenic mechanisms, including RNA toxicity and repeat-associated non-ATG (RAN) translation, and current studies suggest that additional surprising insights into cellular regulatory pathways will emerge in the future.
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Affiliation(s)
- Marianne Goodwin
- Department of Molecular Genetics and Microbiology, University of Florida, College of Medicine, Cancer Genetics Research Complex, 2033 Mowry Road, Gainesville, FL, 32610-3610, USA
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Cardani R, Bugiardini E, Renna LV, Rossi G, Colombo G, Valaperta R, Novelli G, Botta A, Meola G. Overexpression of CUGBP1 in skeletal muscle from adult classic myotonic dystrophy type 1 but not from myotonic dystrophy type 2. PLoS One 2013; 8:e83777. [PMID: 24376746 PMCID: PMC3869793 DOI: 10.1371/journal.pone.0083777] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 11/11/2013] [Indexed: 12/22/2022] Open
Abstract
Myotonic dystrophy type 1 (DM1) and type 2 (DM2) are progressive multisystemic disorders caused by similar mutations at two different genetic loci. The common key feature of DM pathogenesis is nuclear accumulation of mutant RNA which causes aberrant alternative splicing of specific pre-mRNAs by altering the functions of two RNA binding proteins, MBNL1 and CUGBP1. However, DM1 and DM2 show disease-specific features that make them clearly separate diseases suggesting that other cellular and molecular pathways may be involved. In this study we have analysed the histopathological, and biomolecular features of skeletal muscle biopsies from DM1 and DM2 patients in relation to presenting phenotypes to better define the molecular pathogenesis. Particularly, the expression of CUGBP1 protein has been examined to clarify if this factor may act as modifier of disease-specific manifestations in DM. The results indicate that the splicing and muscle pathological alterations observed are related to the clinical phenotype both in DM1 and in DM2 and that CUGBP1 seems to play a role in classic DM1 but not in DM2. In conclusion, our results indicate that multisystemic disease spectrum of DM pathologies may not be explained only by spliceopathy thus confirming that the molecular pathomechanism of DM is more complex than that actually suggested.
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Affiliation(s)
- Rosanna Cardani
- Laboratory of Muscle Histopathology and Molecular Biology, IRCCS-Policlinico San Donato, Milan, Italy
| | - Enrico Bugiardini
- Department of Neurology, University of Milan, IRCCS-Policlinico San Donato, Milan, Italy
| | - Laura V. Renna
- Department of Biosciences, University of Milan, Milan, Italy
| | - Giulia Rossi
- Department of Biomedicine and Prevention, Tor Vergata University of Rome, Rome, Italy
| | | | - Rea Valaperta
- Research Laboratories - Molecular Biology, IRCCS-Policlinico San Donato, Milan, Italy
| | | | - Annalisa Botta
- Department of Biomedicine and Prevention, Tor Vergata University of Rome, Rome, Italy
| | - Giovanni Meola
- Laboratory of Muscle Histopathology and Molecular Biology, IRCCS-Policlinico San Donato, Milan, Italy
- Department of Neurology, University of Milan, IRCCS-Policlinico San Donato, Milan, Italy
- * E-mail:
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MEOLA GIOVANNI. Clinical aspects, molecular pathomechanisms and management of myotonic dystrophies. ACTA MYOLOGICA : MYOPATHIES AND CARDIOMYOPATHIES : OFFICIAL JOURNAL OF THE MEDITERRANEAN SOCIETY OF MYOLOGY 2013; 32:154-65. [PMID: 24803843 PMCID: PMC4006279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Myotonic dystrophy (DM) is the most common adult muscular dystrophy, characterized by autosomal dominant progressive myopathy, myotonia and multiorgan involvement. To date two distinct forms caused by similar mutations have been identified. Myotonic dystrophy type 1 (DM1, Steinert's disease) was described more than 100 years ago and is caused by a (CTG)n expansion in DMPK, while myotonic dystrophy type 2 (DM2) was identified only 18 years ago and is caused by a (CCTG)n expansion in ZNF9/CNBP. When transcribed into CUG/CCUG-containing RNA, mutant transcripts aggregate as nuclear foci that sequester RNA-binding proteins, resulting in spliceopathy of downstream effector genes. Despite clinical and genetic similarities, DM1 and DM2 are distinct disorders requiring different diagnostic and management strategies. DM1 may present in four different forms: congenital, early childhood, adult onset and late-onset oligosymptomatic DM1. Congenital DM1 is the most severe form of DM characterized by extreme muscle weakness and mental retardation. In DM2 the clinical phenotype is extremely variable and there are no distinct clinical subgroups. Congenital and childhood-onset forms are not present in DM2 and, in contrast to DM1, myotonia may be absent even on EMG. Due to the lack of awareness of the disease among clinicians, DM2 remains largely underdiagnosed. The delay in receiving the correct diagnosis after onset of first symptoms is very long in DM: on average more than 5 years for DM1 and more than 14 years for DM2 patients. The long delay in the diagnosis of DM causes unnecessary problems for the patients to manage their lives and anguish with uncertainty of prognosis and treatment.
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Affiliation(s)
- GIOVANNI MEOLA
- Address for correspondence: Giovanni Meola, Department of Neurology University of Milan - IRCCS Policlinico San Donato, via Morandi 30, 20097 San Donato Milanese (MI), Italy. E-mail:
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Bachinski LL, Baggerly KA, Neubauer VL, Nixon TJ, Raheem O, Sirito M, Unruh AK, Zhang J, Nagarajan L, Timchenko LT, Bassez G, Eymard B, Gamez J, Ashizawa T, Mendell JR, Udd B, Krahe R. Most expression and splicing changes in myotonic dystrophy type 1 and type 2 skeletal muscle are shared with other muscular dystrophies. Neuromuscul Disord 2013; 24:227-40. [PMID: 24332166 DOI: 10.1016/j.nmd.2013.11.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 10/30/2013] [Accepted: 11/07/2013] [Indexed: 12/20/2022]
Abstract
The prevailing pathomechanistic paradigm for myotonic dystrophy (DM) is that aberrant expression of embryonic/fetal mRNA/protein isoforms accounts for most aspects of the pleiotropic phenotype. To identify aberrant isoforms in skeletal muscle of DM1 and DM2 patients, we performed exon-array profiling and RT-PCR validation on the largest DM sample set to date, including Duchenne, Becker and tibial muscular dystrophy (NMD) patients as disease controls, and non-disease controls. Strikingly, most expression and splicing changes in DM patients were shared with NMD controls. Comparison between DM and NMD identified almost no significant differences. We conclude that DM1 and DM2 are essentially identical for dysregulation of gene expression, and DM expression changes represent a subset of broader spectrum dystrophic changes. We found no evidence for qualitative splicing differences between DM1 and DM2. While some DM-specific splicing differences exist, most of the DM splicing differences were also seen in NMD controls. SSBP3 exon 6 missplicing was observed in all diseased muscle and led to reduced protein. We conclude there is no widespread DM-specific spliceopathy in skeletal muscle and suggest that missplicing in DM (and NMD) may not be the driving mechanism for the muscle pathology, since the same pathways show expression changes unrelated to splicing.
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Affiliation(s)
- Linda L Bachinski
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Keith A Baggerly
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Valerie L Neubauer
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Tamara J Nixon
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Olayinka Raheem
- Department of Neurology, Tampere University Hospital and Medical School, Tampere, Finland
| | - Mario Sirito
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Anna K Unruh
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jiexin Zhang
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Lalitha Nagarajan
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Lubov T Timchenko
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Guillaume Bassez
- Neuromuscular Reference Center, Henri Mondor University Hospital, INSERM U955, East-Paris University, Créteil, France
| | - Bruno Eymard
- Reference Center for Neuromuscular Diseases, Institute of Myology, Pitié-Salpêtrière Hospital, Paris, France
| | - Josep Gamez
- Neuromuscular Disorders Clinic, Neurology Department, Hospital General Vall d'Hebron, Barcelona, Spain
| | - Tetsuo Ashizawa
- Department of Neurology, McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Jerry R Mendell
- Division of Child Neurology, Nationwide Childrens Hospital, Ohio State University College of Medicine, Columbus, OH, USA
| | - Bjarne Udd
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA; Folkhälsan Institute of Genetics and Department of Medical Genetics, University of Helsinki, Finland; Department of Neurology, Vasa Central Hospital, Finland
| | - Ralf Krahe
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX, USA; Graduate Programs in Human & Molecular Genetics, University of Texas at Houston Graduate School in Biomedical Sciences, Houston, TX, USA; Graduate Programs in Genes & Development, University of Texas at Houston Graduate School in Biomedical Sciences, Houston, TX, USA.
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Vihola A, Sirito M, Bachinski LL, Raheem O, Screen M, Suominen T, Krahe R, Udd B. Altered expression and splicing of Ca(2+) metabolism genes in myotonic dystrophies DM1 and DM2. Neuropathol Appl Neurobiol 2013; 39:390-405. [PMID: 22758909 DOI: 10.1111/j.1365-2990.2012.01289.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
AIMS Myotonic dystrophy types 1 and 2 (DM1 and DM2) are multisystem disorders caused by similar repeat expansion mutations, with similar yet distinct clinical features. Aberrant splicing of multiple effector genes, as well as dysregulation of transcription and translation, has been suggested to underlie different aspects of the complex phenotypes in DM1 and DM2. Ca(2+) plays a central role in both muscle contraction and control of gene expression, and recent expression profiling studies have indicated major perturbations of the Ca(2+) signalling pathways in DM. Here we have further investigated the expression of genes and proteins involved in Ca(2+) metabolism in DM patients, including Ca(2+) channels and Ca(2+) binding proteins. METHODS We used patient muscle biopsies to analyse mRNA expression and splicing of genes by microarray expression profiling and RT-PCR. We studied protein expression by immunohistochemistry and immunoblotting. RESULTS Most of the genes studied showed mRNA up-regulation in expression profiling. When analysed by immunohistochemistry the Ca(2+) release channel ryanodine receptor was reduced in DM1 and DM2, as was calsequestrin 2, a sarcoplasmic reticulum lumen Ca(2+) storage protein. Abnormal splicing of ATP2A1 was more pronounced in DM2 than DM1. CONCLUSIONS We observed abnormal mRNA and protein expression in DM affecting several proteins involved in Ca(2+) metabolism, with some differences between DM1 and DM2. Our protein expression studies are suggestive of a post-transcriptional defect(s) in the myotonic dystrophies.
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Affiliation(s)
- A Vihola
- Folkhälsan Institute of Genetics and Department of Medical Genetics, Haartman Institute, University of Helsinki, Helsinki, Finland.
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Gauthier M, Marteyn A, Denis JA, Cailleret M, Giraud-Triboult K, Aubert S, Lecuyer C, Marie J, Furling D, Vernet R, Yanguas C, Baldeschi C, Pietu G, Peschanski M, Martinat C. A defective Krab-domain zinc-finger transcription factor contributes to altered myogenesis in myotonic dystrophy type 1. Hum Mol Genet 2013; 22:5188-98. [PMID: 23922231 DOI: 10.1093/hmg/ddt373] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Myotonic dystrophy type 1 (DM1) is an RNA-mediated disorder caused by a non-coding CTG repeat expansion that, in particular, provokes functional alteration of CUG-binding proteins. As a consequence, several genes with misregulated alternative splicing have been linked to clinical symptoms. In our search for additional molecular mechanisms that would trigger functional defects in DM1, we took advantage of mutant gene-carrying human embryonic stem cell lines to identify differentially expressed genes. Among the different genes found to be misregulated by DM1 mutation, one strongly downregulated gene encodes a transcription factor, ZNF37A. In this paper, we show that this defect in expression, which derives from a loss of RNA stability, is controlled by the RNA-binding protein, CUGBP1, and is associated with impaired myogenesis-a functional defect reminiscent of that observed in DM1. Loss of the ZNF37A protein results in changes in the expression of the subunit α1 of the receptor for the interleukin 13. This suggests that the pathological molecular mechanisms linking ZNF37A and myogenesis may involve the signaling pathway that is known to promote myoblast recruitment during development and regeneration.
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Molecular mechanisms of muscle atrophy in myotonic dystrophies. Int J Biochem Cell Biol 2013; 45:2280-7. [PMID: 23796888 DOI: 10.1016/j.biocel.2013.06.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 06/11/2013] [Accepted: 06/12/2013] [Indexed: 02/01/2023]
Abstract
Myotonic dystrophy type 1 (DM1) and myotonic dystrophy type 2 (DM2) are multisystemic diseases that primarily affect skeletal muscle, causing myotonia, muscle atrophy, and muscle weakness. DM1 and DM2 pathologies are caused by expansion of CTG and CCTG repeats in non-coding regions of the genes encoding myotonic dystrophy protein kinase (DMPK) and zinc finger protein 9 (ZNF9) respectively. These expansions cause DM pathologies through accumulation of mutant RNAs that alter RNA metabolism in patients' tissues by targeting RNA-binding proteins such as CUG-binding protein 1 (CUGBP1) and Muscle blind-like protein 1 (MBNL1). Despite overwhelming evidence showing the critical role of RNA-binding proteins in DM1 and DM2 pathologies, the downstream pathways by which these RNA-binding proteins cause muscle wasting and muscle weakness are not well understood. This review discusses the molecular pathways by which DM1 and DM2 mutations might cause muscle atrophy and describes progress toward the development of therapeutic interventions for muscle wasting and weakness in DM1 and DM2. This article is part of a Directed Issue entitled: Molecular basis of muscle wasting.
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Sicot G, Gomes-Pereira M. RNA toxicity in human disease and animal models: from the uncovering of a new mechanism to the development of promising therapies. Biochim Biophys Acta Mol Basis Dis 2013; 1832:1390-409. [PMID: 23500957 DOI: 10.1016/j.bbadis.2013.03.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 03/01/2013] [Accepted: 03/04/2013] [Indexed: 01/06/2023]
Abstract
Mutant ribonucleic acid (RNA) molecules can be toxic to the cell, causing human disease through trans-acting dominant mechanisms. RNA toxicity was first described in myotonic dystrophy type 1, a multisystemic disorder caused by the abnormal expansion of a non-coding trinucleotide repeat sequence. The development of multiple and complementary animal models of disease has greatly contributed to clarifying the complex disease pathways mediated by toxic RNA molecules. RNA toxicity is not limited to myotonic dystrophy and spreads to an increasing number of human conditions, which share some unifying pathogenic events mediated by toxic RNA accumulation and disruption of RNA-binding proteins. The remarkable progress in the dissection of disease pathobiology resulted in the rational design of molecular therapies, which have been successfully tested in animal models. Toxic RNA diseases, and in particular myotonic dystrophy, clearly illustrate the critical contribution of animal models of disease in translational research: from gene mutation to disease mechanisms, and ultimately to therapy development. This article is part of a Special Issue entitled: Animal Models of Disease.
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Rojas M, Farr GW, Fernandez CF, Lauden L, McCormack JC, Wolin SL. Yeast Gis2 and its human ortholog CNBP are novel components of stress-induced RNP granules. PLoS One 2012; 7:e52824. [PMID: 23285195 PMCID: PMC3528734 DOI: 10.1371/journal.pone.0052824] [Citation(s) in RCA: 24] [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: 06/11/2012] [Accepted: 11/23/2012] [Indexed: 11/19/2022] Open
Abstract
Although a CCTG expansion in the gene encoding the zinc knuckle protein CNBP causes a common form of muscular dystrophy, the function of both human CNBP and its putative budding yeast ortholog Gis2 remain poorly understood. Here we report the protein interactions of Gis2 and the subcellular locations of both Gis2 and CNBP. We found that Gis2 exhibits RNA-dependent interactions with two proteins involved in mRNA recognition, the poly(A) binding protein and the translation initiation factor eIF4G. We show that Gis2 is a component of two large RNA-protein granules, processing bodies and stress granules, which contain translationally repressed mRNAs. Consistent with a functional ortholog, CNBP also associates with the poly(A) binding protein and accumulates in stress granules during arsenite treatment of human cells. These results implicate both Gis2 and CNBP in mRNA handling during stress.
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Affiliation(s)
- Marta Rojas
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - George W. Farr
- Department of Genetics and Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Cesar F. Fernandez
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Laura Lauden
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - John C. McCormack
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Sandra L. Wolin
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, United States of America
- * E-mail:
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Udd B, Krahe R. The myotonic dystrophies: molecular, clinical, and therapeutic challenges. Lancet Neurol 2012; 11:891-905. [DOI: 10.1016/s1474-4422(12)70204-1] [Citation(s) in RCA: 335] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Lukáš Z, Falk M, Feit J, Souček O, Falková I, Štefančíková L, Janoušová E, Fajkusová L, Zaorálková J, Hrabálková R. Sequestration of MBNL1 in tissues of patients with myotonic dystrophy type 2. Neuromuscul Disord 2012; 22:604-16. [DOI: 10.1016/j.nmd.2012.03.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Revised: 03/02/2012] [Accepted: 03/06/2012] [Indexed: 12/20/2022]
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Abstract
Over the past 20 years, nucleotide repeat expansion disorders have informed our broader understanding of neurodevelopmental and neurodegenerative disease. This is especially true with regard to the contributions of epigenetic mechanisms to neurologic disease pathogenesis. In this review, the authors describe a few of the myriad ways in which epigenetic processes underlie aspects of repeat expansion disorder pathophysiology and discuss how therapies targeted at epigenetic modulation hold promise for many of these disorders.
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Affiliation(s)
- Fang He
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109, USA
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Rhodes JD, Lott MC, Russell SL, Moulton V, Sanderson J, Wormstone IM, Broadway DC. Activation of the innate immune response and interferon signalling in myotonic dystrophy type 1 and type 2 cataracts. Hum Mol Genet 2011; 21:852-62. [DOI: 10.1093/hmg/ddr515] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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