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Liu J, Guo ZN, Yan XL, Yang Y, Huang S. Brain Pathogenesis and Potential Therapeutic Strategies in Myotonic Dystrophy Type 1. Front Aging Neurosci 2021; 13:755392. [PMID: 34867280 PMCID: PMC8634727 DOI: 10.3389/fnagi.2021.755392] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 10/20/2021] [Indexed: 12/17/2022] Open
Abstract
Myotonic dystrophy type 1 (DM1) is the most common muscular dystrophy that affects multiple systems including the muscle and heart. The mutant CTG expansion at the 3′-UTR of the DMPK gene causes the expression of toxic RNA that aggregate as nuclear foci. The foci then interfere with RNA-binding proteins, affecting hundreds of mis-spliced effector genes, leading to aberrant alternative splicing and loss of effector gene product functions, ultimately resulting in systemic disorders. In recent years, increasing clinical, imaging, and pathological evidence have indicated that DM1, though to a lesser extent, could also be recognized as true brain diseases, with more and more researchers dedicating to develop novel therapeutic tools dealing with it. In this review, we summarize the current advances in the pathogenesis and pathology of central nervous system (CNS) deficits in DM1, intervention measures currently being investigated are also highlighted, aiming to promote novel and cutting-edge therapeutic investigations.
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Affiliation(s)
- Jie Liu
- Department of Neurology, Stroke Center & Clinical Trial and Research Center for Stroke, The First Hospital of Jilin University, Changchun, China
- China National Comprehensive Stroke Center, Changchun, China
- Jilin Provincial Key Laboratory of Cerebrovascular Disease, Changchun, China
| | - Zhen-Ni Guo
- Department of Neurology, Stroke Center & Clinical Trial and Research Center for Stroke, The First Hospital of Jilin University, Changchun, China
- China National Comprehensive Stroke Center, Changchun, China
- Jilin Provincial Key Laboratory of Cerebrovascular Disease, Changchun, China
| | - Xiu-Li Yan
- Department of Neurology, Stroke Center & Clinical Trial and Research Center for Stroke, The First Hospital of Jilin University, Changchun, China
| | - Yi Yang
- Department of Neurology, Stroke Center & Clinical Trial and Research Center for Stroke, The First Hospital of Jilin University, Changchun, China
- China National Comprehensive Stroke Center, Changchun, China
- Jilin Provincial Key Laboratory of Cerebrovascular Disease, Changchun, China
| | - Shuo Huang
- Department of Neurology, Stroke Center & Clinical Trial and Research Center for Stroke, The First Hospital of Jilin University, Changchun, China
- China National Comprehensive Stroke Center, Changchun, China
- Jilin Provincial Key Laboratory of Cerebrovascular Disease, Changchun, China
- *Correspondence: Shuo Huang,
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2
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Hinman MN, Richardson JI, Sockol RA, Aronson ED, Stednitz SJ, Murray KN, Berglund JA, Guillemin K. Zebrafish mbnl mutants model physical and molecular phenotypes of myotonic dystrophy. Dis Model Mech 2021; 14:dmm045773. [PMID: 34125183 PMCID: PMC8246264 DOI: 10.1242/dmm.045773] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 05/04/2021] [Indexed: 12/12/2022] Open
Abstract
The muscleblind RNA-binding proteins (MBNL1, MBNL2 and MBNL3) are highly conserved across vertebrates and are important regulators of RNA alternative splicing. Loss of MBNL protein function through sequestration by CUG or CCUG RNA repeats is largely responsible for the phenotypes of the human genetic disorder myotonic dystrophy (DM). We generated the first stable zebrafish (Danio rerio) models of DM-associated MBNL loss of function through mutation of the three zebrafish mbnl genes. In contrast to mouse models, zebrafish double and triple homozygous mbnl mutants were viable to adulthood. Zebrafish mbnl mutants displayed disease-relevant physical phenotypes including decreased body size and impaired movement. They also exhibited widespread alternative splicing changes, including the misregulation of many DM-relevant exons. Physical and molecular phenotypes were more severe in compound mbnl mutants than in single mbnl mutants, suggesting partially redundant functions of Mbnl proteins. The high fecundity and larval optical transparency of this complete series of zebrafish mbnl mutants will make them useful for studying DM-related phenotypes and how individual Mbnl proteins contribute to them, and for testing potential therapeutics. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Melissa N. Hinman
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
| | - Jared I. Richardson
- RNA Institute, State University of New York at Albany, Albany, NY 12222, USA
- Department of Biochemistry and Molecular Biology, Center for NeuroGenetics, University of Florida, Gainesville, FL 32611, USA
| | - Rose A. Sockol
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
| | - Eliza D. Aronson
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
| | - Sarah J. Stednitz
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | - Katrina N. Murray
- Zebrafish International Resource Center, University of Oregon, Eugene, OR 97403, USA
| | - J. Andrew Berglund
- RNA Institute, State University of New York at Albany, Albany, NY 12222, USA
- Department of Biochemistry and Molecular Biology, Center for NeuroGenetics, University of Florida, Gainesville, FL 32611, USA
| | - Karen Guillemin
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
- Humans and the Microbiome Program, CIFAR, Toronto, ON M5G 1M1, Canada
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3
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Fernández-Garibay X, Ortega MA, Cerro-Herreros E, Comelles J, Martínez E, Artero R, Fernández-Costa JM, Ramón-Azcón J. Bioengineered in vitro3D model of myotonic dystrophy type 1 human skeletal muscle. Biofabrication 2021; 13. [PMID: 33836519 DOI: 10.1088/1758-5090/abf6ae] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 04/09/2021] [Indexed: 02/06/2023]
Abstract
Myotonic dystrophy type 1 (DM1) is the most common hereditary myopathy in the adult population. The disease is characterized by progressive skeletal muscle degeneration that produces severe disability. At present, there is still no effective treatment for DM1 patients, but the breakthroughs in understanding the molecular pathogenic mechanisms in DM1 have allowed the testing of new therapeutic strategies. Animal models andin vitrotwo-dimensional cell cultures have been essential for these advances. However, serious concerns exist regarding how faithfully these models reproduce the biological complexity of the disease. Biofabrication tools can be applied to engineer human three-dimensional (3D) culture systems that complement current preclinical research models. Here, we describe the development of the firstin vitro3D model of DM1 human skeletal muscle. Transdifferentiated myoblasts from patient-derived fibroblasts were encapsulated in micromolded gelatin methacryloyl-carboxymethyl cellulose methacrylate hydrogels through photomold patterning on functionalized glass coverslips. These hydrogels present a microstructured topography that promotes myoblasts alignment and differentiation resulting in highly aligned myotubes from both healthy and DM1 cells in a long-lasting cell culture. The DM1 3D microtissues recapitulate the molecular alterations detected in patient biopsies. Importantly, fusion index analyses demonstrate that 3D micropatterning significantly improved DM1 cell differentiation into multinucleated myotubes compared to standard cell cultures. Moreover, the characterization of the 3D cultures of DM1 myotubes detects phenotypes as the reduced thickness of myotubes that can be used for drug testing. Finally, we evaluated the therapeutic effect of antagomiR-23b administration on bioengineered DM1 skeletal muscle microtissues. AntagomiR-23b treatment rescues both molecular DM1 hallmarks and structural phenotype, restoring myotube diameter to healthy control sizes. Overall, these new microtissues represent an improvement over conventional cell culture models and can be used as biomimetic platforms to establish preclinical studies for myotonic dystrophy.
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Affiliation(s)
- Xiomara Fernández-Garibay
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), c/Baldiri Reixac 10-12, E08028 Barcelona, Spain
| | - María A Ortega
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), c/Baldiri Reixac 10-12, E08028 Barcelona, Spain
| | - Estefanía Cerro-Herreros
- University Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Dr Moliner 50, E46100 Burjassot, Valencia, Spain.,Translational Genomics Group, Incliva Health Research Institute, Dr Moliner 50, E46100 Burjassot, Valencia, Spain.,Joint Unit Incliva- CIPF, Dr Moliner 50, E46100 Burjassot, Valencia, Spain
| | - Jordi Comelles
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), c/Baldiri Reixac 10-12, E08028 Barcelona, Spain.,Department of Electronics and Biomedical Engineering, University of Barcelona (UB), c/Martí i Franquès 1-11, E08028 Barcelona, Spain
| | - Elena Martínez
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), c/Baldiri Reixac 10-12, E08028 Barcelona, Spain.,Department of Electronics and Biomedical Engineering, University of Barcelona (UB), c/Martí i Franquès 1-11, E08028 Barcelona, Spain.,Centro de Investigación Biomédica en Red (CIBER), Av. Monforte de Lemos 3-5, Pabellón 11, Planta 0, E28029 Madrid, Spain
| | - Rubén Artero
- University Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Dr Moliner 50, E46100 Burjassot, Valencia, Spain.,Translational Genomics Group, Incliva Health Research Institute, Dr Moliner 50, E46100 Burjassot, Valencia, Spain.,Joint Unit Incliva- CIPF, Dr Moliner 50, E46100 Burjassot, Valencia, Spain
| | - Juan M Fernández-Costa
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), c/Baldiri Reixac 10-12, E08028 Barcelona, Spain
| | - Javier Ramón-Azcón
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), c/Baldiri Reixac 10-12, E08028 Barcelona, Spain.,Institució Catalana de Reserca I Estudis Avançats (ICREA), Passeig de Lluís Companys, 23, E08010 Barcelona, Spain
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4
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Azotla-Vilchis CN, Sanchez-Celis D, Agonizantes-Juárez LE, Suárez-Sánchez R, Hernández-Hernández JM, Peña J, Vázquez-Santillán K, Leyva-García N, Ortega A, Maldonado V, Rangel C, Magaña JJ, Cisneros B, Hernández-Hernández O. Transcriptome Analysis Reveals Altered Inflammatory Pathway in an Inducible Glial Cell Model of Myotonic Dystrophy Type 1. Biomolecules 2021; 11:biom11020159. [PMID: 33530452 PMCID: PMC7910866 DOI: 10.3390/biom11020159] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/22/2021] [Accepted: 01/22/2021] [Indexed: 12/12/2022] Open
Abstract
Myotonic dystrophy type 1 (DM1), the most frequent inherited muscular dystrophy in adults, is caused by the CTG repeat expansion in the 3′UTR of the DMPK gene. Mutant DMPK RNA accumulates in nuclear foci altering diverse cellular functions including alternative splicing regulation. DM1 is a multisystemic condition, with debilitating central nervous system alterations. Although a defective neuroglia communication has been described as a contributor of the brain pathology in DM1, the specific cellular and molecular events potentially affected in glia cells have not been totally recognized. Thus, to study the effects of DM1 mutation on glial physiology, in this work, we have established an inducible DM1 model derived from the MIO-M1 cell line expressing 648 CUG repeats. This new model recreated the molecular hallmarks of DM1 elicited by a toxic RNA gain-of-function mechanism: accumulation of RNA foci colocalized with MBNL proteins and dysregulation of alternative splicing. By applying a microarray whole-transcriptome approach, we identified several gene changes associated with DM1 mutation in MIO-M1 cells, including the immune mediators CXCL10, CCL5, CXCL8, TNFAIP3, and TNFRSF9, as well as the microRNAs miR-222, miR-448, among others, as potential regulators. A gene ontology enrichment analyses revealed that inflammation and immune response emerged as major cellular deregulated processes in the MIO-M1 DM1 cells. Our findings indicate the involvement of an altered immune response in glia cells, opening new windows for the study of glia as potential contributor of the CNS symptoms in DM1.
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Affiliation(s)
- Cuauhtli N. Azotla-Vilchis
- Laboratory of Genomic Medicine, Department of Genetics, Instituto Nacional de Rehabilitación, Luis Guillermo Ibarra Ibarra, Mexico City 14389, Mexico; (C.N.A.-V.); (D.S.-C.); (L.E.A.-J.); (R.S.-S.); (N.L.-G.); (J.J.M.)
- Department of Genetics and Molecular Biology, Centro de Investigación y de Estudios Avanzados, CINVESTAV-IPN, Mexico City 07360, Mexico; (J.M.H.-H.); (B.C.)
| | - Daniel Sanchez-Celis
- Laboratory of Genomic Medicine, Department of Genetics, Instituto Nacional de Rehabilitación, Luis Guillermo Ibarra Ibarra, Mexico City 14389, Mexico; (C.N.A.-V.); (D.S.-C.); (L.E.A.-J.); (R.S.-S.); (N.L.-G.); (J.J.M.)
- Department of Genetics and Molecular Biology, Centro de Investigación y de Estudios Avanzados, CINVESTAV-IPN, Mexico City 07360, Mexico; (J.M.H.-H.); (B.C.)
| | - Luis E. Agonizantes-Juárez
- Laboratory of Genomic Medicine, Department of Genetics, Instituto Nacional de Rehabilitación, Luis Guillermo Ibarra Ibarra, Mexico City 14389, Mexico; (C.N.A.-V.); (D.S.-C.); (L.E.A.-J.); (R.S.-S.); (N.L.-G.); (J.J.M.)
- Escuela Nacional de Ciencias Biologicas-Instituto Politécnico Nacional, Mexico City 11340, Mexico
| | - Rocío Suárez-Sánchez
- Laboratory of Genomic Medicine, Department of Genetics, Instituto Nacional de Rehabilitación, Luis Guillermo Ibarra Ibarra, Mexico City 14389, Mexico; (C.N.A.-V.); (D.S.-C.); (L.E.A.-J.); (R.S.-S.); (N.L.-G.); (J.J.M.)
| | - J. Manuel Hernández-Hernández
- Department of Genetics and Molecular Biology, Centro de Investigación y de Estudios Avanzados, CINVESTAV-IPN, Mexico City 07360, Mexico; (J.M.H.-H.); (B.C.)
| | - Jorge Peña
- Computational and Integrative Genomics Laboratory, Instituto Nacional de Medicina Genómica, Mexico City 14610, Mexico; (J.P.); (C.R.)
- Institute of Mathematical Sciences, Claremont Graduate University, Claremont, CA 91711, USA
| | - Karla Vázquez-Santillán
- Epigenetics Laboratory, Instituto Nacional de Medicina Genomica, Mexico City 14610, Mexico; (K.V.-S.); (V.M.)
| | - Norberto Leyva-García
- Laboratory of Genomic Medicine, Department of Genetics, Instituto Nacional de Rehabilitación, Luis Guillermo Ibarra Ibarra, Mexico City 14389, Mexico; (C.N.A.-V.); (D.S.-C.); (L.E.A.-J.); (R.S.-S.); (N.L.-G.); (J.J.M.)
| | - Arturo Ortega
- Department of Toxicology, Centro de Investigación y de Estudios Avanzados, CINVESTAV-IPN, Mexico City 07360, Mexico;
| | - Vilma Maldonado
- Epigenetics Laboratory, Instituto Nacional de Medicina Genomica, Mexico City 14610, Mexico; (K.V.-S.); (V.M.)
| | - Claudia Rangel
- Computational and Integrative Genomics Laboratory, Instituto Nacional de Medicina Genómica, Mexico City 14610, Mexico; (J.P.); (C.R.)
| | - Jonathan J. Magaña
- Laboratory of Genomic Medicine, Department of Genetics, Instituto Nacional de Rehabilitación, Luis Guillermo Ibarra Ibarra, Mexico City 14389, Mexico; (C.N.A.-V.); (D.S.-C.); (L.E.A.-J.); (R.S.-S.); (N.L.-G.); (J.J.M.)
- School of Engineering and Sciences, Department of Bioengineering, Tecnológico de Monterrey-Campus, Mexico City 14380, Mexico
| | - Bulmaro Cisneros
- Department of Genetics and Molecular Biology, Centro de Investigación y de Estudios Avanzados, CINVESTAV-IPN, Mexico City 07360, Mexico; (J.M.H.-H.); (B.C.)
| | - Oscar Hernández-Hernández
- Laboratory of Genomic Medicine, Department of Genetics, Instituto Nacional de Rehabilitación, Luis Guillermo Ibarra Ibarra, Mexico City 14389, Mexico; (C.N.A.-V.); (D.S.-C.); (L.E.A.-J.); (R.S.-S.); (N.L.-G.); (J.J.M.)
- Correspondence: or ; Tel.: +52-55-5999-1000 (ext. 14710)
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5
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Antisense Transcription across Nucleotide Repeat Expansions in Neurodegenerative and Neuromuscular Diseases: Progress and Mysteries. Genes (Basel) 2020; 11:genes11121418. [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] [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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6
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Nikonova E, Kao SY, Ravichandran K, Wittner A, Spletter ML. Conserved functions of RNA-binding proteins in muscle. Int J Biochem Cell Biol 2019; 110:29-49. [PMID: 30818081 DOI: 10.1016/j.biocel.2019.02.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Revised: 02/21/2019] [Accepted: 02/23/2019] [Indexed: 12/13/2022]
Abstract
Animals require different types of muscle for survival, for example for circulation, motility, reproduction and digestion. Much emphasis in the muscle field has been placed on understanding how transcriptional regulation generates diverse types of muscle during development. Recent work indicates that alternative splicing and RNA regulation are as critical to muscle development, and altered function of RNA-binding proteins causes muscle disease. Although hundreds of genes predicted to bind RNA are expressed in muscles, many fewer have been functionally characterized. We present a cross-species view summarizing what is known about RNA-binding protein function in muscle, from worms and flies to zebrafish, mice and humans. In particular, we focus on alternative splicing regulated by the CELF, MBNL and RBFOX families of proteins. We discuss the systemic nature of diseases associated with loss of RNA-binding proteins in muscle, focusing on mis-regulation of CELF and MBNL in myotonic dystrophy. These examples illustrate the conservation of RNA-binding protein function and the marked utility of genetic model systems in understanding mechanisms of RNA regulation.
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Affiliation(s)
- Elena Nikonova
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-University München, Großhaderner Str. 9, 82152, Martinsried-Planegg, Germany
| | - Shao-Yen Kao
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-University München, Großhaderner Str. 9, 82152, Martinsried-Planegg, Germany
| | - Keshika Ravichandran
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-University München, Großhaderner Str. 9, 82152, Martinsried-Planegg, Germany
| | - Anja Wittner
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-University München, Großhaderner Str. 9, 82152, Martinsried-Planegg, Germany
| | - Maria L Spletter
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-University München, Großhaderner Str. 9, 82152, Martinsried-Planegg, Germany; Center for Integrated Protein Science Munich (CIPSM) at the Department of Chemistry, Ludwig-Maximilians-Universität München, Munich, Germany.
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7
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Glineburg MR, Todd PK, Charlet-Berguerand N, Sellier C. Repeat-associated non-AUG (RAN) translation and other molecular mechanisms in Fragile X Tremor Ataxia Syndrome. Brain Res 2018; 1693:43-54. [PMID: 29453961 PMCID: PMC6010627 DOI: 10.1016/j.brainres.2018.02.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 01/31/2018] [Accepted: 02/02/2018] [Indexed: 11/11/2022]
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset inherited neurodegenerative disorder characterized by progressive intention tremor, gait ataxia and dementia associated with mild brain atrophy. The cause of FXTAS is a premutation expansion, of 55 to 200 CGG repeats localized within the 5'UTR of FMR1. These repeats are transcribed in the sense and antisense directions into mutants RNAs, which have increased expression in FXTAS. Furthermore, CGG sense and CCG antisense expanded repeats are translated into novel proteins despite their localization in putatively non-coding regions of the transcript. Here we focus on two proposed disease mechanisms for FXTAS: 1) RNA gain-of-function, whereby the mutant RNAs bind specific proteins and preclude their normal functions, and 2) repeat-associated non-AUG (RAN) translation, whereby translation through the CGG or CCG repeats leads to the production of toxic homopolypeptides, which in turn interfere with a variety of cellular functions. Here, we analyze the data generated to date on both of these potential molecular mechanisms and lay out a path forward for determining which factors drive FXTAS pathogenicity.
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Affiliation(s)
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA; Veteran's Affairs Medical Center, Ann Arbor, MI 48105, USA
| | - Nicolas Charlet-Berguerand
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France
| | - Chantal Sellier
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France.
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8
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Braz SO, Acquaire J, Gourdon G, Gomes-Pereira M. Of Mice and Men: Advances in the Understanding of Neuromuscular Aspects of Myotonic Dystrophy. Front Neurol 2018; 9:519. [PMID: 30050493 PMCID: PMC6050950 DOI: 10.3389/fneur.2018.00519] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Accepted: 06/12/2018] [Indexed: 12/26/2022] Open
Abstract
Intensive effort has been directed toward the modeling of myotonic dystrophy (DM) in mice, in order to reproduce human disease and to provide useful tools to investigate molecular and cellular pathogenesis and test efficient therapies. Mouse models have contributed to dissect the multifaceted impact of the DM mutation in various tissues, cell types and in a pleiotropy of pathways, through the expression of toxic RNA transcripts. Changes in alternative splicing, transcription, translation, intracellular RNA localization, polyadenylation, miRNA metabolism and phosphorylation of disease intermediates have been described in different tissues. Some of these events have been directly associated with specific disease symptoms in the skeletal muscle and heart of mice, offering the molecular explanation for individual disease phenotypes. In the central nervous system (CNS), however, the situation is more complex. We still do not know how the molecular abnormalities described translate into CNS dysfunction, nor do we know if the correction of individual molecular events will provide significant therapeutic benefits. The variability in model design and phenotypes described so far requires a thorough and critical analysis. In this review we discuss the recent contributions of mouse models to the understanding of neuromuscular aspects of disease, therapy development, and we provide a reflective assessment of our current limitations and pressing questions that remain unanswered.
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Affiliation(s)
- Sandra O Braz
- Laboratory CTGDM, INSERM UMR1163, Paris, France.,Institut Imagine, Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Julien Acquaire
- Laboratory CTGDM, INSERM UMR1163, Paris, France.,Institut Imagine, Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Geneviève Gourdon
- Laboratory CTGDM, INSERM UMR1163, Paris, France.,Institut Imagine, Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Mário Gomes-Pereira
- Laboratory CTGDM, INSERM UMR1163, Paris, France.,Institut Imagine, Université Paris Descartes-Sorbonne Paris Cité, Paris, France
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9
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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 DOI: 10.1002/cphy.c170002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [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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10
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Imbriano C, Molinari S. Alternative Splicing of Transcription Factors Genes in Muscle Physiology and Pathology. Genes (Basel) 2018; 9:genes9020107. [PMID: 29463057 PMCID: PMC5852603 DOI: 10.3390/genes9020107] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 02/10/2018] [Accepted: 02/13/2018] [Indexed: 12/13/2022] Open
Abstract
Skeletal muscle formation is a multi-step process that is governed by complex networks of transcription factors. The regulation of their functions is in turn multifaceted, including several mechanisms, among them alternative splicing (AS) plays a primary role. On the other hand, altered AS has a role in the pathogenesis of numerous muscular pathologies. Despite these premises, the causal role played by the altered splicing pattern of transcripts encoding myogenic transcription factors in neuromuscular diseases has been neglected so far. In this review, we systematically investigate what has been described about the AS patterns of transcription factors both in the physiology of the skeletal muscle formation process and in neuromuscular diseases, in the hope that this may be useful in re-evaluating the potential role of altered splicing of transcription factors in such diseases.
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Affiliation(s)
- Carol Imbriano
- University of Modena and Reggio Emilia, Department of Life Sciences, Modena, Italy.
| | - Susanna Molinari
- University of Modena and Reggio Emilia, Department of Life Sciences, Modena, Italy.
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11
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Gourdon G, Meola G. Myotonic Dystrophies: State of the Art of New Therapeutic Developments for the CNS. Front Cell Neurosci 2017; 11:101. [PMID: 28473756 PMCID: PMC5397409 DOI: 10.3389/fncel.2017.00101] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 03/27/2017] [Indexed: 12/12/2022] Open
Abstract
Myotonic dystrophies are multisystemic diseases characterized not only by muscle and heart dysfunction but also by CNS alteration. They are now recognized as brain diseases affecting newborns and children for myotonic dystrophy type 1 and adults for both myotonic dystrophy type 1 and type 2. In the past two decades, much progress has been made in understanding the mechanisms underlying the DM symptoms allowing development of new molecular therapeutic tools with the ultimate aim of curing the disease. This review describes the state of the art for the characterization of CNS related symptoms, the development of molecular strategies to target the CNS as well as the available tools for screening and testing new possible treatments.
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Affiliation(s)
- Genevieve Gourdon
- Institut National de la Santé et de la Recherche Médicale UMR1163Paris, France.,Laboratory CTGDM, Institut Imagine, Université Paris Descartes-Sorbonne Paris CitéParis, France
| | - Giovanni Meola
- Department of Biomedical Sciences for Health, Policlinico San Donato (IRCCS), University of MilanMilan, Italy
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12
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13
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Loesch DZ, Annesley SJ, Trost N, Bui MQ, Lay ST, Storey E, De Piazza SW, Sanislav O, Francione LM, Hammersley EM, Tassone F, Francis D, Fisher PR. Novel Blood Biomarkers Are Associated with White Matter Lesions in Fragile X- Associated Tremor/Ataxia Syndrome. NEURODEGENER DIS 2016; 17:22-30. [PMID: 27602566 PMCID: PMC10964908 DOI: 10.1159/000446803] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 05/13/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The need for accessible cellular biomarkers of neurodegeneration in carriers of the fragile X mental retardation 1 (FMR1) premutation (PM) alleles. OBJECTIVE To assess the mitochondrial status and respiration in blood lymphoblasts from PM carriers manifesting the fragile X-associated tremor/ataxia syndrome (FXTAS) and non-FXTAS carriers, and their relationship with the brain white matter lesions. METHODS Oxygen consumption rates (OCR) and ATP synthesis using a Seahorse XFe24 Extracellular Flux Analyser, and steady-state parameters of mitochondrial function were assessed in cultured lymphoblasts from 16 PM males (including 11 FXTAS patients) and 9 matched controls. The regional white matter hyperintensity (WMH) scores were obtained from MRI. RESULTS Mitochondrial respiratory activity was significantly elevated in lymphoblasts from PM carriers compared with controls, with a 2- to 3-fold increase in basal and maximum OCR attributable to complex I activity, and ATP synthesis, accompanied by unaltered mitochondrial mass and membrane potential. The changes, which were more advanced in FXTAS patients, were significantly associated with the WMH scores in the supratentorial regions. CONCLUSION The dramatic increase in mitochondrial activity in lymphoblasts from PM carriers may represent either the early stages of disease (specific alterations in short-lived blood cells) or an activation of the lymphocytes under pathological situations. These changes may provide early, convenient blood biomarkers of clinical involvements.
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Affiliation(s)
- Danuta Z. Loesch
- Department of Psychology and Counselling, School of Psychology and Public Health, Melbourne, Vic., Australia
| | - Sarah J. Annesley
- Discipline of Microbiology, Department of Physiology Anatomy and Microbiology, School of Life Sciences, College of Science Health and Engineering, La Trobe University, Melbourne, Vic., Australia
| | - Nicholas Trost
- Medical Imaging Department, St Vincent's Hospital, Melbourne, Vic., Australia
| | - Minh Q. Bui
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Vic., Australia
| | - Sui T. Lay
- Discipline of Microbiology, Department of Physiology Anatomy and Microbiology, School of Life Sciences, College of Science Health and Engineering, La Trobe University, Melbourne, Vic., Australia
| | - Elsdon Storey
- Department of Medicine (Neuroscience), Monash University (Alfred Hospital Campus), Melbourne, Vic., Australia
| | - Shawn W. De Piazza
- Discipline of Microbiology, Department of Physiology Anatomy and Microbiology, School of Life Sciences, College of Science Health and Engineering, La Trobe University, Melbourne, Vic., Australia
| | - Oana Sanislav
- Discipline of Microbiology, Department of Physiology Anatomy and Microbiology, School of Life Sciences, College of Science Health and Engineering, La Trobe University, Melbourne, Vic., Australia
| | - Lisa M. Francione
- Discipline of Microbiology, Department of Physiology Anatomy and Microbiology, School of Life Sciences, College of Science Health and Engineering, La Trobe University, Melbourne, Vic., Australia
| | - Eleanor M. Hammersley
- Department of Psychology and Counselling, School of Psychology and Public Health, Melbourne, Vic., Australia
| | | | - David Francis
- Cytomolecular Diagnostic Research, Victorian Clinical Genetic Services, Murdoch Institute, Royal Children's Hospital, Melbourne, Vic., Australia
| | - Paul R. Fisher
- Discipline of Microbiology, Department of Physiology Anatomy and Microbiology, School of Life Sciences, College of Science Health and Engineering, La Trobe University, Melbourne, Vic., Australia
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Abstract
Genomic DNA methylation functions to repress gene expression by interfering with transcription factor binding and/or recruiting repressive chromatin machinery. Recent data support contribution of regulated DNA methylation to embryonic pluripotency, development, and tissue differentiation; this important epigenetic mark is chemically stable yet enzymatically reversible-and heritable through the germline. Importantly, all the major components involved in dynamic DNA methylation are conserved in zebrafish, including the factors that "write, read, and erase" this mark. Therefore, the zebrafish has become an excellent model for studying most biological processes associated with DNA methylation in mammals. Here we briefly review the zebrafish model for studying DNA methylation and describe a series of methods for performing genome-wide DNA methylation analysis. We address and provide methods for methylated DNA immunoprecipitation followed by sequencing (MeDIP-Seq), bisulfite sequencing (BS-Seq), and reduced representation bisulfite sequencing (RRBS-Seq).
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Affiliation(s)
- P J Murphy
- University of Utah School of Medicine, Salt Lake City, UT, United States
| | - B R Cairns
- University of Utah School of Medicine, Salt Lake City, UT, United States
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15
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Gudde AEEG, González-Barriga A, van den Broek WJAA, Wieringa B, Wansink DG. A low absolute number of expanded transcripts is involved in myotonic dystrophy type 1 manifestation in muscle. Hum Mol Genet 2016; 25:1648-62. [PMID: 26908607 PMCID: PMC4805313 DOI: 10.1093/hmg/ddw042] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 02/09/2016] [Indexed: 12/15/2022] Open
Abstract
Muscular manifestation of myotonic dystrophy type 1 (DM1), a common inheritable degenerative multisystem disorder, is mainly caused by expression of RNA from a (CTG·CAG)n-expanded DM1 locus. Here, we report on comparative profiling of expression of normal and expanded endogenous or transgenic transcripts in skeletal muscle cells and biopsies from DM1 mouse models and patients in order to help us in understanding the role of this RNA-mediated toxicity. In tissue of HSALR mice, the most intensely used ‘muscle-only’ model in the DM1 field, RNA from the α-actin (CTG)250 transgene was at least 1000-fold more abundant than that from the Dmpk gene, or the DMPK gene in humans. Conversely, the DMPK transgene in another line, DM500/DMSXL mice, was expressed ∼10-fold lower than the endogenous gene. Temporal regulation of expanded RNA expression differed between models. Onset of expression occurred remarkably late in HSALR myoblasts during in vitro myogenesis whereas Dmpk or DMPK (trans)genes were expressed throughout proliferation and differentiation phases. Importantly, quantification of absolute transcript numbers revealed that normal and expanded Dmpk/DMPK transcripts in mouse models and DM1 patients are low-abundance RNA species. Northern blotting, reverse transcriptase–quantitative polymerase chain reaction, RNA-sequencing and fluorescent in situ hybridization analyses showed that they occur at an absolute number between one and a few dozen molecules per cell. Our findings refine the current RNA dominance theory for DM1 pathophysiology, as anomalous factor binding to expanded transcripts and formation of soluble or insoluble ribonucleoprotein aggregates must be nucleated by only few expanded DMPK transcripts and therefore be a small numbers game.
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Affiliation(s)
- Anke E E G Gudde
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands
| | - Anchel González-Barriga
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands
| | - Walther J A A van den Broek
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands
| | - Bé Wieringa
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands
| | - Derick G Wansink
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands
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16
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Michel L, Huguet-Lachon A, Gourdon G. Sense and Antisense DMPK RNA Foci Accumulate in DM1 Tissues during Development. PLoS One 2015; 10:e0137620. [PMID: 26339785 PMCID: PMC4560382 DOI: 10.1371/journal.pone.0137620] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Accepted: 08/20/2015] [Indexed: 01/22/2023] Open
Abstract
Myotonic dystrophy type 1 (DM1) is caused by an unstable expanded CTG repeat located within the DMPK gene 3’UTR. The nature, severity and age at onset of DM1 symptoms are very variable in patients. Different forms of the disease are described, among which the congenital form (CDM) is the most severe. Molecular mechanisms of DM1 are well characterized for the adult form and involve accumulation of mutant DMPK RNA forming foci in the nucleus. These RNA foci sequester proteins from the MBNL family and deregulate CELF proteins. These proteins are involved in many cellular mechanisms such as alternative splicing, transcriptional, translational and post-translational regulation miRNA regulation as well as mRNA polyadenylation and localization. All these mechanisms can be impaired in DM1 because of the deregulation of CELF and MBNL functions. The mechanisms involved in CDM are not clearly described. In order to get insight into the mechanisms underlying CDM, we investigated if expanded RNA nuclear foci, one of the molecular hallmarks of DM1, could be detected in human DM1 fetal tissues, as well as in embryonic and neonatal tissues from transgenic mice carrying the human DMPK gene with an expanded CTG repeat. We observed very abundant RNA foci formed by sense DMPK RNA and, to a lesser extent, antisense DMPK RNA foci. Sense DMPK RNA foci clearly co-localized with MBNL1 and MBNL2 proteins. In addition, we studied DMPK sense and antisense expression during development in the transgenic mice. We found that DMPK sense and antisense transcripts are expressed from embryonic and fetal stages in heart, muscle and brain and are regulated during development. These results suggest that mechanisms underlying DM1 and CDM involved common players including toxic expanded RNA forming numerous nuclear foci at early stages during development.
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MESH Headings
- Alternative Splicing
- Animals
- Animals, Newborn
- Brain/metabolism
- Brain/pathology
- CCAAT-Enhancer-Binding Protein-delta/genetics
- CCAAT-Enhancer-Binding Protein-delta/metabolism
- Cell Nucleus/genetics
- Cell Nucleus/metabolism
- Disease Models, Animal
- Embryo, Mammalian
- Gene Expression Regulation, Developmental
- Humans
- Mice
- Mice, Transgenic
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Myocardium/metabolism
- Myocardium/pathology
- Myotonic Dystrophy/genetics
- Myotonic Dystrophy/metabolism
- Myotonic Dystrophy/pathology
- Myotonin-Protein Kinase/genetics
- Myotonin-Protein Kinase/metabolism
- RNA, Antisense/genetics
- RNA, Antisense/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA-Binding Proteins/genetics
- RNA-Binding Proteins/metabolism
- Signal Transduction
- Trinucleotide Repeat Expansion
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Affiliation(s)
- Lise Michel
- Inserm UMR 1163, Paris, France
- Paris Descartes—Sorbonne Paris Cité University, Imagine Institute, Paris, France
| | - Aline Huguet-Lachon
- Inserm UMR 1163, Paris, France
- Paris Descartes—Sorbonne Paris Cité University, Imagine Institute, Paris, France
| | - Geneviève Gourdon
- Inserm UMR 1163, Paris, France
- Paris Descartes—Sorbonne Paris Cité University, Imagine Institute, Paris, France
- * E-mail:
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17
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Plantié E, Migocka-Patrzałek M, Daczewska M, Jagla K. Model organisms in the fight against muscular dystrophy: lessons from drosophila and Zebrafish. Molecules 2015; 20:6237-53. [PMID: 25859781 PMCID: PMC6272363 DOI: 10.3390/molecules20046237] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 03/31/2015] [Accepted: 04/01/2015] [Indexed: 01/01/2023] Open
Abstract
Muscular dystrophies (MD) are a heterogeneous group of genetic disorders that cause muscle weakness, abnormal contractions and muscle wasting, often leading to premature death. More than 30 types of MD have been described so far; those most thoroughly studied are Duchenne muscular dystrophy (DMD), myotonic dystrophy type 1 (DM1) and congenital MDs. Structurally, physiologically and biochemically, MDs affect different types of muscles and cause individual symptoms such that genetic and molecular pathways underlying their pathogenesis thus remain poorly understood. To improve our knowledge of how MD-caused muscle defects arise and to find efficacious therapeutic treatments, different animal models have been generated and applied. Among these, simple non-mammalian Drosophila and zebrafish models have proved most useful. This review discusses how zebrafish and Drosophila MD have helped to identify genetic determinants of MDs and design innovative therapeutic strategies with a special focus on DMD, DM1 and congenital MDs.
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Affiliation(s)
- Emilie Plantié
- GReD (Genetics, Reproduction and Development laboratory), INSERM U1103, CNRS UMR6293, University of Clermont-Ferrand, 28 place Henri-Dunant, 63000 Clermont-Ferrand, France; E-Mail:
| | - Marta Migocka-Patrzałek
- Department of Animal Developmental Biology, Institute of Experimental Biology, University of Wroclaw, 21 Sienkiewicza Street, 50-335 Wroclaw, Poland; E-Mails: (M.M.-P.); (M.D.)
| | - Małgorzata Daczewska
- Department of Animal Developmental Biology, Institute of Experimental Biology, University of Wroclaw, 21 Sienkiewicza Street, 50-335 Wroclaw, Poland; E-Mails: (M.M.-P.); (M.D.)
| | - Krzysztof Jagla
- GReD (Genetics, Reproduction and Development laboratory), INSERM U1103, CNRS UMR6293, University of Clermont-Ferrand, 28 place Henri-Dunant, 63000 Clermont-Ferrand, France; E-Mail:
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18
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Hagerman PJ, Hagerman RJ. Fragile X-associated tremor/ataxia syndrome. Ann N Y Acad Sci 2015; 1338:58-70. [PMID: 25622649 PMCID: PMC4363162 DOI: 10.1111/nyas.12693] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 12/04/2014] [Accepted: 12/18/2014] [Indexed: 12/20/2022]
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder that affects some but not all carriers of small, noncoding CGG-repeat expansions (55-200 repeats; premutation) within the fragile X gene (FMR1). Principal features of FXTAS include intention tremor, cerebellar ataxia, Parkinsonism, memory and executive function deficits, autonomic dysfunction, brain atrophy with white matter disease, and cognitive decline. Although FXTAS was originally considered to be confined to the premutation range, rare individuals with a gray zone (45-54 repeats) or an unmethylated full mutation (>200 repeats) allele have now been described, the constant feature of the disorder remaining the requirement for FMR1 expression, in contradistinction to the gene silencing mechanism of fragile X syndrome. Although transcriptional activity is required for FXTAS pathogenesis, the specific trigger(s) for FXTAS pathogenesis remains elusive, highlighting the need for more research in this area. This need is underscored by recent neuroimaging findings of changes in the central nervous system that consistently appear well before the onset of clinical symptoms, thus creating an opportunity to delay or prevent the appearance of FXTAS.
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Affiliation(s)
- Paul J Hagerman
- Department of Biochemistry and Molecular Medicine, University of California , Davis , School of Medicine, Davis, California; The MIND Institute, University of California , Davis , Health System, Sacramento, California
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19
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deLorimier E, Coonrod LA, Copperman J, Taber A, Reister EE, Sharma K, Todd PK, Guenza MG, Berglund JA. Modifications to toxic CUG RNAs induce structural stability, rescue mis-splicing in a myotonic dystrophy cell model and reduce toxicity in a myotonic dystrophy zebrafish model. Nucleic Acids Res 2014; 42:12768-78. [PMID: 25303993 PMCID: PMC4227782 DOI: 10.1093/nar/gku941] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
CUG repeat expansions in the 3′ UTR of dystrophia myotonica protein kinase (DMPK) cause myotonic dystrophy type 1 (DM1). As RNA, these repeats elicit toxicity by sequestering splicing proteins, such as MBNL1, into protein–RNA aggregates. Structural studies demonstrate that CUG repeats can form A-form helices, suggesting that repeat secondary structure could be important in pathogenicity. To evaluate this hypothesis, we utilized structure-stabilizing RNA modifications pseudouridine (Ψ) and 2′-O-methylation to determine if stabilization of CUG helical conformations affected toxicity. CUG repeats modified with Ψ or 2′-O-methyl groups exhibited enhanced structural stability and reduced affinity for MBNL1. Molecular dynamics and X-ray crystallography suggest a potential water-bridging mechanism for Ψ-mediated CUG repeat stabilization. Ψ modification of CUG repeats rescued mis-splicing in a DM1 cell model and prevented CUG repeat toxicity in zebrafish embryos. This study indicates that the structure of toxic RNAs has a significant role in controlling the onset of neuromuscular diseases.
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Affiliation(s)
- Elaine deLorimier
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
| | - Leslie A Coonrod
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
| | - Jeremy Copperman
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
| | - Alex Taber
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
| | - Emily E Reister
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
| | - Kush Sharma
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
| | - Marina G Guenza
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
| | - J Andrew Berglund
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
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20
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Ketley A, Chen CZ, Li X, Arya S, Robinson TE, Granados-Riveron J, Udosen I, Morris GE, Holt I, Furling D, Chaouch S, Haworth B, Southall N, Shinn P, Zheng W, Austin CP, Hayes CJ, Brook JD. High-content screening identifies small molecules that remove nuclear foci, affect MBNL distribution and CELF1 protein levels via a PKC-independent pathway in myotonic dystrophy cell lines. Hum Mol Genet 2013; 23:1551-62. [PMID: 24179176 PMCID: PMC3929092 DOI: 10.1093/hmg/ddt542] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Myotonic dystrophy (DM) is a multi-system neuromuscular disorder for which there is no treatment. We have developed a medium throughput phenotypic assay, based on the identification of nuclear foci in DM patient cell lines using in situ hybridization and high-content imaging to screen for potentially useful therapeutic compounds. A series of further assays based on molecular features of DM have also been employed. Two compounds that reduce and/or remove nuclear foci have been identified, Ro 31-8220 and chromomycin A3. Ro 31-8220 is a PKC inhibitor, previously shown to affect the hyperphosphorylation of CELF1 and ameliorate the cardiac phenotype in a DM1 mouse model. We show that the same compound eliminates nuclear foci, reduces MBNL1 protein in the nucleus, affects ATP2A1 alternative splicing and reduces steady-state levels of CELF1 protein. We demonstrate that this effect is independent of PKC activity and conclude that this compound may be acting on alternative kinase targets within DM pathophysiology. Understanding the activity profile for this compound is key for the development of targeted therapeutics in the treatment of DM.
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Affiliation(s)
- Ami Ketley
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
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