1
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Verbeeren J, Teixeira J, Garcia SMDA. The Muscleblind-like protein MBL-1 regulates microRNA expression in Caenorhabditis elegans through an evolutionarily conserved autoregulatory mechanism. PLoS Genet 2023; 19:e1011109. [PMID: 38134228 PMCID: PMC10773944 DOI: 10.1371/journal.pgen.1011109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 01/08/2024] [Accepted: 12/12/2023] [Indexed: 12/24/2023] Open
Abstract
The Muscleblind-like (MBNL) family is a highly conserved set of RNA-binding proteins (RBPs) that regulate RNA metabolism during the differentiation of various animal tissues. Functional insufficiency of MBNL affects muscle and central nervous system development, and contributes to the myotonic dystrophies (DM), a set of incurable multisystemic disorders. Studies on the regulation of MBNL genes are essential to provide insight into the gene regulatory networks controlled by MBNL proteins and to understand how dysregulation within these networks causes disease. In this study, we demonstrate the evolutionary conservation of an autoregulatory mechanism that governs the function of MBNL proteins by generating two distinct protein isoform types through alternative splicing. Our aim was to further our understanding of the regulatory principles that underlie this conserved feedback loop in a whole-organismal context, and to address the biological significance of the respective isoforms. Using an alternative splicing reporter, our studies show that, during development of the Caenorhabditis elegans central nervous system, the orthologous mbl-1 gene shifts production from long protein isoforms that localize to the nucleus to short isoforms that also localize to the cytoplasm. Using isoform-specific CRISPR/Cas9-generated strains, we showed that expression of short MBL-1 protein isoforms is required for healthy neuromuscular function and neurodevelopment, while expression of long MBL-1 protein isoforms is dispensable, emphasizing a key role for cytoplasmic functionalities of the MBL-1 protein. Furthermore, RNA-seq and lifespan analyses indicated that short MBL-1 isoforms are crucial regulators of miRNA expression and, in consequence, required for normal lifespan. In conclusion, this study provides support for the disruption of cytoplasmic RNA metabolism as a contributor in myotonic dystrophy and paves the way for further exploration of miRNA regulation through MBNL proteins during development and in disease models.
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Affiliation(s)
- Jens Verbeeren
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
| | - Joana Teixeira
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
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2
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Gazzola M, Martinat C. Unlocking the Complexity of Neuromuscular Diseases: Insights from Human Pluripotent Stem Cell-Derived Neuromuscular Junctions. Int J Mol Sci 2023; 24:15291. [PMID: 37894969 PMCID: PMC10607237 DOI: 10.3390/ijms242015291] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 09/26/2023] [Accepted: 10/16/2023] [Indexed: 10/29/2023] Open
Abstract
Over the past 20 years, the use of pluripotent stem cells to mimic the complexities of the human neuromuscular junction has received much attention. Deciphering the key mechanisms underlying the establishment and maturation of this complex synapse has been driven by the dual goals of addressing developmental questions and gaining insight into neuromuscular disorders. This review aims to summarise the evolution and sophistication of in vitro neuromuscular junction models developed from the first differentiation of human embryonic stem cells into motor neurons to recent neuromuscular organoids. We also discuss the potential offered by these models to decipher different neuromuscular diseases characterised by defects in the presynaptic compartment, the neuromuscular junction, and the postsynaptic compartment. Finally, we discuss the emerging field that considers the use of these techniques in drug screening assay and the challenges they will face in the future.
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Affiliation(s)
- Morgan Gazzola
- INSERM U861, Institute for Stem Cell Therapy and Exploration of Monogenic Diseases, 91100 Corbeil-Essonnes, France;
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3
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Wright SE, Todd PK. Native functions of short tandem repeats. eLife 2023; 12:e84043. [PMID: 36940239 PMCID: PMC10027321 DOI: 10.7554/elife.84043] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 03/08/2023] [Indexed: 03/21/2023] Open
Abstract
Over a third of the human genome is comprised of repetitive sequences, including more than a million short tandem repeats (STRs). While studies of the pathologic consequences of repeat expansions that cause syndromic human diseases are extensive, the potential native functions of STRs are often ignored. Here, we summarize a growing body of research into the normal biological functions for repetitive elements across the genome, with a particular focus on the roles of STRs in regulating gene expression. We propose reconceptualizing the pathogenic consequences of repeat expansions as aberrancies in normal gene regulation. From this altered viewpoint, we predict that future work will reveal broader roles for STRs in neuronal function and as risk alleles for more common human neurological diseases.
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Affiliation(s)
- Shannon E Wright
- Department of Neurology, University of Michigan–Ann ArborAnn ArborUnited States
- Neuroscience Graduate Program, University of Michigan–Ann ArborAnn ArborUnited States
- Department of Neuroscience, Picower InstituteCambridgeUnited States
| | - Peter K Todd
- Department of Neurology, University of Michigan–Ann ArborAnn ArborUnited States
- VA Ann Arbor Healthcare SystemAnn ArborUnited States
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4
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Souidi A, Nakamori M, Zmojdzian M, Jagla T, Renaud Y, Jagla K. Deregulations of miR-1 and its target Multiplexin promote dilated cardiomyopathy associated with myotonic dystrophy type 1. EMBO Rep 2023; 24:e56616. [PMID: 36852954 PMCID: PMC10074075 DOI: 10.15252/embr.202256616] [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: 12/06/2022] [Revised: 02/03/2023] [Accepted: 02/14/2023] [Indexed: 03/01/2023] Open
Abstract
Myotonic dystrophy type 1 (DM1) is the most common muscular dystrophy in adults. It is caused by the excessive expansion of noncoding CTG repeats, which when transcribed affects the functions of RNA-binding factors with adverse effects on alternative splicing, processing, and stability of a large set of muscular and cardiac transcripts. Among these effects, inefficient processing and down-regulation of muscle- and heart-specific miRNA, miR-1, have been reported in DM1 patients, but the impact of reduced miR-1 on DM1 pathogenesis has been unknown. Here, we use Drosophila DM1 models to explore the role of miR-1 in cardiac dysfunction in DM1. We show that miR-1 down-regulation in the heart leads to dilated cardiomyopathy (DCM), a DM1-associated phenotype. We combined in silico screening for miR-1 targets with transcriptional profiling of DM1 cardiac cells to identify miR-1 target genes with potential roles in DCM. We identify Multiplexin (Mp) as a new cardiac miR-1 target involved in DM1. Mp encodes a collagen protein involved in cardiac tube formation in Drosophila. Mp and its human ortholog Col15A1 are both highly enriched in cardiac cells of DCM-developing DM1 flies and in heart samples from DM1 patients with DCM, respectively. When overexpressed in the heart, Mp induces DCM, whereas its attenuation rescues the DCM phenotype of aged DM1 flies. Reduced levels of miR-1 and consecutive up-regulation of its target Mp/Col15A1 might be critical in DM1-associated DCM.
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Affiliation(s)
- Anissa Souidi
- iGReD Genetics Reproduction and Development Institute, Clermont Auvergne University, Clermont-Ferrand, France
| | - Masayuki Nakamori
- Department of Neurology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Monika Zmojdzian
- iGReD Genetics Reproduction and Development Institute, Clermont Auvergne University, Clermont-Ferrand, France
| | - Teresa Jagla
- iGReD Genetics Reproduction and Development Institute, Clermont Auvergne University, Clermont-Ferrand, France
| | - Yoan Renaud
- iGReD Genetics Reproduction and Development Institute, Clermont Auvergne University, Clermont-Ferrand, France
| | - Krzysztof Jagla
- iGReD Genetics Reproduction and Development Institute, Clermont Auvergne University, Clermont-Ferrand, France
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5
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Alam SR, Mahadevan MS, Periasamy A. Detecting RNA-Protein Interactions With EGFP-Cy3 FRET by Acceptor Photobleaching. Curr Protoc 2023; 3:e689. [PMID: 36821783 DOI: 10.1002/cpz1.689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Förster Resonance Energy Transfer (FRET) is a great tool for cell biologists to investigate molecular interactions in live specimens. FRET is a distance-dependent phenomenon which can detect molecular interactions at distances between 1-10 nm. Several FRET approaches are reported in the literature for live and fixed cells to study protein-protein interactions; this protocol provides details of acceptor photobleaching as a FRET method to study RNA-Protein interactions. Cy3-labeled RNA foci (FRET acceptors) are photobleached at the intra-cellular site of interest (the nuclei) and the intensity of the EGFP-tagged proteins (FRET donors) at that same site are measured pre- and post- photobleaching. In principle, FRET is detected if the intensity of EGFP increases after photobleaching of Cy3. This protocol describes necessary steps and appropriate controls to conduct FRET measurements by the acceptor photobleaching method. Successful applications of this protocol will provide data to support the conclusion that EGFP-labeled proteins directly interact with Cy3-labeled RNA at the site of photobleaching. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol: FRET in fixed cells Alternate Protocol: FRET in live cells.
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Affiliation(s)
- Shagufta Rehman Alam
- W. M. Keck Center for Cellular Imaging, University of Virginia, Charlottesville, Virginia
| | - Mani S Mahadevan
- Department of Pathology, University of Virginia, Charlottesville, Virginia
| | - Ammasi Periasamy
- W. M. Keck Center for Cellular Imaging, University of Virginia, Charlottesville, Virginia.,Departments of Biology and Biomedical Engineering, University of Virginia, Charlottesville, Virginia
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6
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Todorow V, Hintze S, Schoser B, Meinke P. Nuclear envelope transmembrane proteins involved in genome organization are misregulated in myotonic dystrophy type 1 muscle. Front Cell Dev Biol 2023; 10:1007331. [PMID: 36699009 PMCID: PMC9868253 DOI: 10.3389/fcell.2022.1007331] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 12/27/2022] [Indexed: 01/11/2023] Open
Abstract
Myotonic dystrophy type 1 is a multisystemic disorder with predominant muscle and neurological involvement. Despite a well described pathomechanism, which is primarily a global missplicing due to sequestration of RNA-binding proteins, there are still many unsolved questions. One such question is the disease etiology in the different affected tissues. We observed alterations at the nuclear envelope in primary muscle cell cultures before. This led us to reanalyze a published RNA-sequencing dataset of DM1 and control muscle biopsies regarding the misregulation of NE proteins. We could identify several muscle NE protein encoding genes to be misregulated depending on the severity of the muscle phenotype. Among these misregulated genes were NE transmembrane proteins (NETs) involved in nuclear-cytoskeletal coupling as well as genome organization. For selected genes, we could confirm that observed gene-misregulation led to protein expression changes. Furthermore, we investigated if genes known to be under expression-regulation by genome organization NETs were also misregulated in DM1 biopsies, which revealed that misregulation of two NETs alone is likely responsible for differential expression of about 10% of all genes being differentially expressed in DM1. Notably, the majority of NETs identified here to be misregulated in DM1 muscle are mutated in Emery-Dreifuss muscular dystrophy or clinical similar muscular dystrophies, suggesting a broader similarity on the molecular level for muscular dystrophies than anticipated. This shows not only the importance of muscle NETs in muscle health and disease, but also highlights the importance of the NE in DM1 disease progression.
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7
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Rosario R, Stewart HL, Choudhury NR, Michlewski G, Charlet‐Berguerand N, Anderson RA. Evidence for a fragile X messenger ribonucleoprotein 1 (FMR1) mRNA gain-of-function toxicity mechanism contributing to the pathogenesis of fragile X-associated premature ovarian insufficiency. FASEB J 2022; 36:e22612. [PMID: 36250920 PMCID: PMC9828574 DOI: 10.1096/fj.202200468rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 09/22/2022] [Accepted: 10/03/2022] [Indexed: 01/12/2023]
Abstract
Fragile X-associated premature ovarian insufficiency (FXPOI) is among a family of disorders caused by expansion of a CGG trinucleotide repeat sequence located in the 5' untranslated region (UTR) of the fragile X messenger ribonucleoprotein 1 (FMR1) gene on the X chromosome. Women with FXPOI have a depleted ovarian follicle population, resulting in amenorrhea, hypoestrogenism, and loss of fertility before the age of 40. FXPOI is caused by expansions of the CGG sequence to lengths between 55 and 200 repeats, known as a FMRI premutation, however the mechanism by which the premutation drives disease pathogenesis remains unclear. Two main hypotheses exist, which describe an mRNA toxic gain-of-function mechanism or a protein-based mechanism, where repeat-associated non-AUG (RAN) translation results in the production of an abnormal protein, called FMRpolyG. Here, we have developed an in vitro granulosa cell model of the FMR1 premutation by ectopically expressing CGG-repeat RNA and FMRpolyG protein. We show that expanded CGG-repeat RNA accumulated in intranuclear RNA structures, and these aggregates were able to cause significant granulosa cell death independent of FMRpolyG expression. Using an innovative RNA pulldown, mass spectrometry-based approach we have identified proteins that are specifically sequestered by CGG RNA aggregates in granulosa cells in vitro, and thus may be deregulated as consequence of this interaction. Furthermore, we have demonstrated reduced expression of three proteins identified via our RNA pulldown (FUS, PA2G4 and TRA2β) in ovarian follicles in a FMR1 premutation mouse model. Collectively, these data provide evidence for the contribution of an mRNA gain-of-function mechanism to FXPOI disease biology.
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Affiliation(s)
- Roseanne Rosario
- MRC Centre for Reproductive Health, Queen's Medical Research InstituteUniversity of EdinburghEdinburghUK,Biomedical SciencesUniversity of EdinburghEdinburghUK
| | - Hazel L. Stewart
- MRC Centre for Reproductive Health, Queen's Medical Research InstituteUniversity of EdinburghEdinburghUK
| | | | - Gracjan Michlewski
- Infection MedicineUniversity of EdinburghEdinburghUK,Zhejiang University‐University of Edinburgh InstituteZhejiang UniversityZhejiangP.R. China,Dioscuri Centre for RNA‐Protein Interactions in Human Health and DiseaseInternational Institute of Molecular and Cell Biology in WarsawWarsawPoland
| | - Nicholas Charlet‐Berguerand
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC)INSERM U 1258, CNRS UMR 7104, Université of StrasbourgIllkirchFrance
| | - Richard A. Anderson
- MRC Centre for Reproductive Health, Queen's Medical Research InstituteUniversity of EdinburghEdinburghUK
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8
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Baud A, Derbis M, Tutak K, Sobczak K. Partners in crime: Proteins implicated in
RNA
repeat expansion diseases. WIRES RNA 2022; 13:e1709. [PMID: 35229468 PMCID: PMC9539487 DOI: 10.1002/wrna.1709] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 12/07/2021] [Accepted: 12/08/2021] [Indexed: 11/06/2022]
Affiliation(s)
- Anna Baud
- Department of Gene Expression Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University Poznan Poland
| | - Magdalena Derbis
- Department of Gene Expression Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University Poznan Poland
| | - Katarzyna Tutak
- Department of Gene Expression Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University Poznan Poland
| | - Krzysztof Sobczak
- Department of Gene Expression Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University Poznan Poland
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9
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García-Puga M, Saenz-Antoñanzas A, Matheu A, López de Munain A. Targeting Myotonic Dystrophy Type 1 with Metformin. Int J Mol Sci 2022; 23:ijms23052901. [PMID: 35270043 PMCID: PMC8910924 DOI: 10.3390/ijms23052901] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/28/2022] [Accepted: 03/02/2022] [Indexed: 02/01/2023] Open
Abstract
Myotonic dystrophy type 1 (DM1) is a multisystemic disorder of genetic origin. Progressive muscular weakness, atrophy and myotonia are its most prominent neuromuscular features, while additional clinical manifestations in multiple organs are also common. Overall, DM1 features resemble accelerated aging. There is currently no cure or specific treatment for myotonic dystrophy patients. However, in recent years a great effort has been made to identify potential new therapeutic strategies for DM1 patients. Metformin is a biguanide antidiabetic drug, with potential to delay aging at cellular and organismal levels. In DM1, different studies revealed that metformin rescues multiple phenotypes of the disease. This review provides an overview of recent findings describing metformin as a novel therapy to combat DM1 and their link with aging.
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Affiliation(s)
- Mikel García-Puga
- Neuromuscular Diseases Group, Biodonostia Health Research Institute, 20014 San Sebastian, Spain;
- Cellular Oncology Group, Biodonostia Health Research Institute, 20014 San Sebastian, Spain;
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED-CIBER), Carlos III Institute, 28031 Madrid, Spain
| | - Ander Saenz-Antoñanzas
- Cellular Oncology Group, Biodonostia Health Research Institute, 20014 San Sebastian, Spain;
| | - Ander Matheu
- Cellular Oncology Group, Biodonostia Health Research Institute, 20014 San Sebastian, Spain;
- Basque Foundation for Science (IKERBASQUE), 48009 Bilbao, Spain
- Centro de Investigación Biomédica en Red Fragilidad y Envejecimiento Saludable (CIBERfes), Carlos III Institute, 28029 Madrid, Spain
- Correspondence: (A.M.); (A.L.d.M.); Tel.: +34-943-006-073 (A.M.); +34-943-006-294 (A.L.d.M.)
| | - Adolfo López de Munain
- Neuromuscular Diseases Group, Biodonostia Health Research Institute, 20014 San Sebastian, Spain;
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED-CIBER), Carlos III Institute, 28031 Madrid, Spain
- Neurology Department, Donostia University Hospital, OSAKIDETZA, 20014 San Sebastian, Spain
- Department of Neurosciences, Faculty of Medicine and Nursery, University of the Basque Country, 20014 San Sebastian, Spain
- Correspondence: (A.M.); (A.L.d.M.); Tel.: +34-943-006-073 (A.M.); +34-943-006-294 (A.L.d.M.)
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10
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Cerro-Herreros E, González-Martínez I, Moreno N, Espinosa-Espinosa J, Fernández-Costa JM, Colom-Rodrigo A, Overby SJ, Seoane-Miraz D, Poyatos-García J, Vilchez JJ, López de Munain A, Varela MA, Wood MJ, Pérez-Alonso M, Llamusí B, Artero R. Preclinical characterization of antagomiR-218 as a potential treatment for myotonic dystrophy. MOLECULAR THERAPY. NUCLEIC ACIDS 2021; 26:174-191. [PMID: 34513303 PMCID: PMC8413838 DOI: 10.1016/j.omtn.2021.07.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Accepted: 07/17/2021] [Indexed: 12/13/2022]
Abstract
Myotonic dystrophy type 1 (DM1) is a rare neuromuscular disease caused by expansion of unstable CTG repeats in a non-coding region of the DMPK gene. CUG expansions in mutant DMPK transcripts sequester MBNL1 proteins in ribonuclear foci. Depletion of this protein is a primary contributor to disease symptoms such as muscle weakness and atrophy and myotonia, yet upregulation of endogenous MBNL1 levels may compensate for this sequestration. Having previously demonstrated that antisense oligonucleotides against miR-218 boost MBNL1 expression and rescue phenotypes in disease models, here we provide preclinical characterization of an antagomiR-218 molecule using the HSALR mouse model and patient-derived myotubes. In HSALR, antagomiR-218 reached 40–60 pM 2 weeks after injection, rescued molecular and functional phenotypes in a dose- and time-dependent manner, and showed a good toxicity profile after a single subcutaneous administration. In muscle tissue, antagomiR rescued the normal subcellular distribution of Mbnl1 and did not alter the proportion of myonuclei containing CUG foci. In patient-derived cells, antagomiR-218 improved defective fusion and differentiation and rescued up to 34% of the gene expression alterations found in the transcriptome of patient cells. Importantly, miR-218 was found to be upregulated in DM1 muscle biopsies, pinpointing this microRNA (miRNA) as a relevant therapeutic target.
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Affiliation(s)
- Estefanía Cerro-Herreros
- University Research Institute for Biotechnology and Biomedicine (BIOTECMED), Universidad de Valencia, Dr. Moliner, 50, 46100 Burjasot, Valencia, Spain.,Incliva Biomedical Research Institute, Avenida Menéndez Pelayo 4 acc, 46010 Valencia, Spain
| | - Irene González-Martínez
- University Research Institute for Biotechnology and Biomedicine (BIOTECMED), Universidad de Valencia, Dr. Moliner, 50, 46100 Burjasot, Valencia, Spain.,Incliva Biomedical Research Institute, Avenida Menéndez Pelayo 4 acc, 46010 Valencia, Spain
| | - Nerea Moreno
- University Research Institute for Biotechnology and Biomedicine (BIOTECMED), Universidad de Valencia, Dr. Moliner, 50, 46100 Burjasot, Valencia, Spain.,Incliva Biomedical Research Institute, Avenida Menéndez Pelayo 4 acc, 46010 Valencia, Spain
| | - Jorge Espinosa-Espinosa
- University Research Institute for Biotechnology and Biomedicine (BIOTECMED), Universidad de Valencia, Dr. Moliner, 50, 46100 Burjasot, Valencia, Spain.,Incliva Biomedical Research Institute, Avenida Menéndez Pelayo 4 acc, 46010 Valencia, Spain
| | - Juan M Fernández-Costa
- University Research Institute for Biotechnology and Biomedicine (BIOTECMED), Universidad de Valencia, Dr. Moliner, 50, 46100 Burjasot, Valencia, Spain.,Incliva Biomedical Research Institute, Avenida Menéndez Pelayo 4 acc, 46010 Valencia, Spain
| | - Anna Colom-Rodrigo
- University Research Institute for Biotechnology and Biomedicine (BIOTECMED), Universidad de Valencia, Dr. Moliner, 50, 46100 Burjasot, Valencia, Spain.,Incliva Biomedical Research Institute, Avenida Menéndez Pelayo 4 acc, 46010 Valencia, Spain
| | - Sarah J Overby
- University Research Institute for Biotechnology and Biomedicine (BIOTECMED), Universidad de Valencia, Dr. Moliner, 50, 46100 Burjasot, Valencia, Spain.,Incliva Biomedical Research Institute, Avenida Menéndez Pelayo 4 acc, 46010 Valencia, Spain
| | - David Seoane-Miraz
- Department of Paediatrics, University of Oxford, John Radcliffe Hospital, Headley Way, OX3 9DU, Oxford, UK.,MDUK Oxford Neuromuscular Centre, University of Oxford, Oxford, UK
| | - Javier Poyatos-García
- The IISLAFE Health Research Institute, Avenida Fernando Abril Martorell, 106 Torre A 7 planta, 46026 Valencia, Spain.,Neuromuscular Reference Centre ERN EURO-NMD and Neuromuscular Pathology and Ataxia Research Group, Hospital La Fe Health Research Institute, Valencia, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Juan J Vilchez
- The IISLAFE Health Research Institute, Avenida Fernando Abril Martorell, 106 Torre A 7 planta, 46026 Valencia, Spain.,Neuromuscular Reference Centre ERN EURO-NMD and Neuromuscular Pathology and Ataxia Research Group, Hospital La Fe Health Research Institute, Valencia, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Adolfo López de Munain
- Biodonostia Health Research Institute, P° Dr. Beguiristain s/n, 20014 Donostia-San Sebastián, Spain.,Hospital Universitario Donostia-Osakidetza-Departamento de Neurociencias-Universidad del Pais Vasco-CIBERNED
| | - Miguel A Varela
- Department of Paediatrics, University of Oxford, John Radcliffe Hospital, Headley Way, OX3 9DU, Oxford, UK.,MDUK Oxford Neuromuscular Centre, University of Oxford, Oxford, UK
| | - Matthew J Wood
- Department of Paediatrics, University of Oxford, John Radcliffe Hospital, Headley Way, OX3 9DU, Oxford, UK.,MDUK Oxford Neuromuscular Centre, University of Oxford, Oxford, UK
| | - Manuel Pérez-Alonso
- University Research Institute for Biotechnology and Biomedicine (BIOTECMED), Universidad de Valencia, Dr. Moliner, 50, 46100 Burjasot, Valencia, Spain.,Incliva Biomedical Research Institute, Avenida Menéndez Pelayo 4 acc, 46010 Valencia, Spain
| | - Beatriz Llamusí
- University Research Institute for Biotechnology and Biomedicine (BIOTECMED), Universidad de Valencia, Dr. Moliner, 50, 46100 Burjasot, Valencia, Spain.,Incliva Biomedical Research Institute, Avenida Menéndez Pelayo 4 acc, 46010 Valencia, Spain
| | - Rubén Artero
- University Research Institute for Biotechnology and Biomedicine (BIOTECMED), Universidad de Valencia, Dr. Moliner, 50, 46100 Burjasot, Valencia, Spain.,Incliva Biomedical Research Institute, Avenida Menéndez Pelayo 4 acc, 46010 Valencia, Spain
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11
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Drosophila Heart as a Model for Cardiac Development and Diseases. Cells 2021; 10:cells10113078. [PMID: 34831301 PMCID: PMC8623483 DOI: 10.3390/cells10113078] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 11/04/2021] [Accepted: 11/05/2021] [Indexed: 01/26/2023] Open
Abstract
The Drosophila heart, also referred to as the dorsal vessel, pumps the insect blood, the hemolymph. The bilateral heart primordia develop from the most dorsally located mesodermal cells, migrate coordinately, and fuse to form the cardiac tube. Though much simpler, the fruit fly heart displays several developmental and functional similarities to the vertebrate heart and, as we discuss here, represents an attractive model system for dissecting mechanisms of cardiac aging and heart failure and identifying genes causing congenital heart diseases. Fast imaging technologies allow for the characterization of heartbeat parameters in the adult fly and there is growing evidence that cardiac dysfunction in human diseases could be reproduced and analyzed in Drosophila, as discussed here for heart defects associated with the myotonic dystrophy type 1. Overall, the power of genetics and unsuspected conservation of genes and pathways puts Drosophila at the heart of fundamental and applied cardiac research.
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12
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Verdile V, Guizzo G, Ferrante G, Paronetto MP. RNA Targeting in Inherited Neuromuscular Disorders: Novel Therapeutic Strategies to Counteract Mis-Splicing. Cells 2021; 10:cells10112850. [PMID: 34831073 PMCID: PMC8616048 DOI: 10.3390/cells10112850] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 10/08/2021] [Accepted: 10/18/2021] [Indexed: 01/14/2023] Open
Abstract
Neuromuscular disorders represent multifaceted abnormal conditions, with little or no cure, leading to patient deaths from complete muscle wasting and atrophy. Despite strong efforts in the past decades, development of effective treatments is still urgently needed. Advent of next-generation sequencing technologies has allowed identification of novel genes and mutations associated with neuromuscular pathologies, highlighting splicing defects as essential players. Deciphering the significance and relative contributions of defective RNA metabolism will be instrumental to address and counteract these malignancies. We review here recent progress on the role played by alternative splicing in ensuring functional neuromuscular junctions (NMJs), and its involvement in the pathogenesis of NMJ-related neuromuscular disorders, with particular emphasis on congenital myasthenic syndromes and muscular dystrophies. We will also discuss novel strategies based on oligonucleotides designed to bind their cognate sequences in the RNA or targeting intermediary of mRNA metabolism. These efforts resulted in several chemical classes of RNA molecules that have recently proven to be clinically effective, more potent and better tolerated than previous strategies.
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Affiliation(s)
- Veronica Verdile
- Laboratory of Molecular and Cellular Neurobiology, Fondazione Santa Lucia, CERC, 00143 Rome, Italy; (V.V.); (G.G.); (G.F.)
- Department of Movement, Human and Health Sciences, University of Rome Foro Italico, Piazza Lauro de Bosis 6, 00135 Rome, Italy
| | - Gloria Guizzo
- Laboratory of Molecular and Cellular Neurobiology, Fondazione Santa Lucia, CERC, 00143 Rome, Italy; (V.V.); (G.G.); (G.F.)
| | - Gabriele Ferrante
- Laboratory of Molecular and Cellular Neurobiology, Fondazione Santa Lucia, CERC, 00143 Rome, Italy; (V.V.); (G.G.); (G.F.)
| | - Maria Paola Paronetto
- Laboratory of Molecular and Cellular Neurobiology, Fondazione Santa Lucia, CERC, 00143 Rome, Italy; (V.V.); (G.G.); (G.F.)
- Department of Movement, Human and Health Sciences, University of Rome Foro Italico, Piazza Lauro de Bosis 6, 00135 Rome, Italy
- Correspondence:
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13
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Matilainen O, Ribeiro ARS, Verbeeren J, Cetinbas M, Sood H, Sadreyev RI, Garcia SMDA. Loss of muscleblind splicing factor shortens Caenorhabditis elegans lifespan by reducing the activity of p38 MAPK/PMK-1 and transcription factors ATF-7 and Nrf/SKN-1. Genetics 2021; 219:6325509. [PMID: 34849877 PMCID: PMC8633093 DOI: 10.1093/genetics/iyab114] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 07/03/2021] [Indexed: 12/13/2022] Open
Abstract
Muscleblind-like splicing regulators (MBNLs) are RNA-binding factors that have an important role in developmental processes. Dysfunction of these factors is a key contributor of different neuromuscular degenerative disorders, including Myotonic Dystrophy type 1 (DM1). Since DM1 is a multisystemic disease characterized by symptoms resembling accelerated aging, we asked which cellular processes do MBNLs regulate that make them necessary for normal lifespan. By utilizing the model organism Caenorhabditis elegans, we found that loss of MBL-1 (the sole ortholog of mammalian MBNLs), which is known to be required for normal lifespan, shortens lifespan by decreasing the activity of p38 MAPK/PMK-1 as well as the function of transcription factors ATF-7 and SKN-1. Furthermore, we show that mitochondrial stress caused by the knockdown of mitochondrial electron transport chain components promotes the longevity of mbl-1 mutants in a partially PMK-1-dependent manner. Together, the data establish a mechanism of how DM1-associated loss of muscleblind affects lifespan. Furthermore, this study suggests that mitochondrial stress could alleviate symptoms caused by the dysfunction of muscleblind splicing factor, creating a potential approach to investigate for therapy.
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Affiliation(s)
- Olli Matilainen
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki 00790, Finland
| | - Ana R S Ribeiro
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki 00790, Finland
| | - Jens Verbeeren
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki 00790, Finland
| | - Murat Cetinbas
- Department of Molecular Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Heini Sood
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki 00790, Finland
| | - Ruslan I Sadreyev
- Department of Molecular Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Susana M D A Garcia
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki 00790, Finland
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14
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Kao SY, Nikonova E, Chaabane S, Sabani A, Martitz A, Wittner A, Heemken J, Straub T, Spletter ML. A Candidate RNAi Screen Reveals Diverse RNA-Binding Protein Phenotypes in Drosophila Flight Muscle. Cells 2021; 10:2505. [PMID: 34685485 PMCID: PMC8534295 DOI: 10.3390/cells10102505] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 09/14/2021] [Accepted: 09/18/2021] [Indexed: 12/30/2022] Open
Abstract
The proper regulation of RNA processing is critical for muscle development and the fine-tuning of contractile ability among muscle fiber-types. RNA binding proteins (RBPs) regulate the diverse steps in RNA processing, including alternative splicing, which generates fiber-type specific isoforms of structural proteins that confer contractile sarcomeres with distinct biomechanical properties. Alternative splicing is disrupted in muscle diseases such as myotonic dystrophy and dilated cardiomyopathy and is altered after intense exercise as well as with aging. It is therefore important to understand splicing and RBP function, but currently, only a small fraction of the hundreds of annotated RBPs expressed in muscle have been characterized. Here, we demonstrate the utility of Drosophila as a genetic model system to investigate basic developmental mechanisms of RBP function in myogenesis. We find that RBPs exhibit dynamic temporal and fiber-type specific expression patterns in mRNA-Seq data and display muscle-specific phenotypes. We performed knockdown with 105 RNAi hairpins targeting 35 RBPs and report associated lethality, flight, myofiber and sarcomere defects, including flight muscle phenotypes for Doa, Rm62, mub, mbl, sbr, and clu. Knockdown phenotypes of spliceosome components, as highlighted by phenotypes for A-complex components SF1 and Hrb87F (hnRNPA1), revealed level- and temporal-dependent myofibril defects. We further show that splicing mediated by SF1 and Hrb87F is necessary for Z-disc stability and proper myofibril development, and strong knockdown of either gene results in impaired localization of kettin to the Z-disc. Our results expand the number of RBPs with a described phenotype in muscle and underscore the diversity in myofibril and transcriptomic phenotypes associated with splicing defects. Drosophila is thus a powerful model to gain disease-relevant insight into cellular and molecular phenotypes observed when expression levels of splicing factors, spliceosome components and splicing dynamics are altered.
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Affiliation(s)
- Shao-Yen Kao
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany; (S.-Y.K.); (E.N.); (S.C.); (A.W.); (J.H.)
| | - Elena Nikonova
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany; (S.-Y.K.); (E.N.); (S.C.); (A.W.); (J.H.)
| | - Sabrina Chaabane
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany; (S.-Y.K.); (E.N.); (S.C.); (A.W.); (J.H.)
| | - Albiona Sabani
- Department of Biology, University of Wisconsin at Madison, 1117 W. Johnson St., Madison, WI 53706, USA;
| | - Alexandra Martitz
- Molecular Nutrition Medicine, Else Kröner-Fresenius Center, Technical University of Munich, 85354 Freising, Germany;
| | - Anja Wittner
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany; (S.-Y.K.); (E.N.); (S.C.); (A.W.); (J.H.)
| | - Jakob Heemken
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany; (S.-Y.K.); (E.N.); (S.C.); (A.W.); (J.H.)
| | - Tobias Straub
- Biomedical Center, Bioinformatics Core Facility, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany;
| | - Maria L. Spletter
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany; (S.-Y.K.); (E.N.); (S.C.); (A.W.); (J.H.)
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15
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Rosario R, Anderson R. The molecular mechanisms that underlie fragile X-associated premature ovarian insufficiency: is it RNA or protein based? Mol Hum Reprod 2021; 26:727-737. [PMID: 32777047 PMCID: PMC7566375 DOI: 10.1093/molehr/gaaa057] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 08/03/2020] [Indexed: 01/30/2023] Open
Abstract
The FMR1 gene contains a polymorphic CGG trinucleotide sequence within its 5′ untranslated region. More than 200 CGG repeats (termed a full mutation) underlie the severe neurodevelopmental condition fragile X syndrome, while repeat lengths that range between 55 and 200 (termed a premutation) result in the conditions fragile X-associated tremor/ataxia syndrome and fragile X-associated premature ovarian insufficiency (FXPOI). Premutations in FMR1 are the most common monogenic cause of premature ovarian insufficiency and are routinely tested for clinically; however, the mechanisms that contribute to the pathology are still largely unclear. As studies in this field move towards unravelling the molecular mechanisms involved in FXPOI aetiology, we review the evidence surrounding the two main theories which describe an RNA toxic gain-of-function mechanism, resulting in the loss of function of RNA-binding proteins, or a protein-based mechanism, where repeat-associated non-AUG translation leads to the formation of an abnormal polyglycine containing protein, called FMRpolyG.
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Affiliation(s)
- Roseanne Rosario
- MRC Centre for Reproductive Health, Queens Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - Richard Anderson
- MRC Centre for Reproductive Health, Queens Medical Research Institute, University of Edinburgh, Edinburgh, UK
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16
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Todorow V, Hintze S, Kerr ARW, Hehr A, Schoser B, Meinke P. Transcriptome Analysis in a Primary Human Muscle Cell Differentiation Model for Myotonic Dystrophy Type 1. Int J Mol Sci 2021; 22:8607. [PMID: 34445314 PMCID: PMC8395314 DOI: 10.3390/ijms22168607] [Citation(s) in RCA: 7] [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: 06/28/2021] [Revised: 07/30/2021] [Accepted: 08/06/2021] [Indexed: 01/01/2023] Open
Abstract
Myotonic dystrophy type 1 (DM1) is caused by CTG-repeat expansions leading to a complex pathology with a multisystemic phenotype that primarily affects the muscles and brain. Despite a multitude of information, especially on the alternative splicing of several genes involved in the pathology, information about additional factors contributing to the disease development is still lacking. We performed RNAseq and gene expression analyses on proliferating primary human myoblasts and differentiated myotubes. GO-term analysis indicates that in myoblasts and myotubes, different molecular pathologies are involved in the development of the muscular phenotype. Gene set enrichment for splicing reveals the likelihood of whole, differentiation stage specific, splicing complexes that are misregulated in DM1. These data add complexity to the alternative splicing phenotype and we predict that it will be of high importance for therapeutic interventions to target not only mature muscle, but also satellite cells.
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Affiliation(s)
- Vanessa Todorow
- Department of Neurology, Friedrich-Baur-Institute, LMU Klinikum, Ludwig-Maximilians-University Munich, 80336 Munich, Germany
| | - Stefan Hintze
- Department of Neurology, Friedrich-Baur-Institute, LMU Klinikum, Ludwig-Maximilians-University Munich, 80336 Munich, Germany
| | - Alastair R W Kerr
- Cancer Biomarker Centre, CRUK Manchester Institute, University of Manchester, Manchester SK10 4TG, UK
| | - Andreas Hehr
- Centre for Human Genetics, 93047 Regensburg, Germany
| | - Benedikt Schoser
- Department of Neurology, Friedrich-Baur-Institute, LMU Klinikum, Ludwig-Maximilians-University Munich, 80336 Munich, Germany
| | - Peter Meinke
- Department of Neurology, Friedrich-Baur-Institute, LMU Klinikum, Ludwig-Maximilians-University Munich, 80336 Munich, Germany
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17
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Ketley A, Wojciechowska M, Ghidelli-Disse S, Bamborough P, Ghosh TK, Morato ML, Sedehizadeh S, Malik NA, Tang Z, Powalowska P, Tanner M, Billeter-Clark R, Trueman RC, Geiszler PC, Agostini A, Othman O, Bösche M, Bantscheff M, Rüdiger M, Mossakowska DE, Drewry DH, Zuercher WJ, Thornton CA, Drewes G, Uings I, Hayes CJ, Brook JD. CDK12 inhibition reduces abnormalities in cells from patients with myotonic dystrophy and in a mouse model. Sci Transl Med 2021; 12:12/541/eaaz2415. [PMID: 32350131 DOI: 10.1126/scitranslmed.aaz2415] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 09/16/2019] [Accepted: 02/25/2020] [Indexed: 12/17/2022]
Abstract
Myotonic dystrophy type 1 (DM1) is an RNA-based disease with no current treatment. It is caused by a transcribed CTG repeat expansion within the 3' untranslated region of the dystrophia myotonica protein kinase (DMPK) gene. Mutant repeat expansion transcripts remain in the nuclei of patients' cells, forming distinct microscopically detectable foci that contribute substantially to the pathophysiology of the condition. Here, we report small-molecule inhibitors that remove nuclear foci and have beneficial effects in the HSALR mouse model, reducing transgene expression, leading to improvements in myotonia, splicing, and centralized nuclei. Using chemoproteomics in combination with cell-based assays, we identify cyclin-dependent kinase 12 (CDK12) as a druggable target for this condition. CDK12 is a protein elevated in DM1 cell lines and patient muscle biopsies, and our results showed that its inhibition led to reduced expression of repeat expansion RNA. Some of the inhibitors identified in this study are currently the subject of clinical trials for other indications and provide valuable starting points for a drug development program in DM1.
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Affiliation(s)
- Ami Ketley
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Marzena Wojciechowska
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Sonja Ghidelli-Disse
- Cellzome GmbH, Molecular Discovery Research, GlaxoSmithKline, Meyerhofstrasse 1, 61997 Heidelberg, Germany
| | - Paul Bamborough
- Computational and Modelling Sciences, GlaxoSmithKline, Medicines Research Centre, Hertfordshire SG1 2NY, UK
| | - Tushar K Ghosh
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Marta Lopez Morato
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Saam Sedehizadeh
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Naveed Altaf Malik
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Zhenzhi Tang
- Department of Neurology, University of Rochester Medical Center, Rochester, NY 14642-0001, USA
| | - Paulina Powalowska
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK.,School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Matthew Tanner
- Department of Neurology, University of Rochester Medical Center, Rochester, NY 14642-0001, USA
| | - Rudolf Billeter-Clark
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Rebecca C Trueman
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Philippine C Geiszler
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Alessandra Agostini
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Othman Othman
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Markus Bösche
- Cellzome GmbH, Molecular Discovery Research, GlaxoSmithKline, Meyerhofstrasse 1, 61997 Heidelberg, Germany
| | - Marcus Bantscheff
- Cellzome GmbH, Molecular Discovery Research, GlaxoSmithKline, Meyerhofstrasse 1, 61997 Heidelberg, Germany
| | - Martin Rüdiger
- Screening Profiling and Mechanistic Biology, GlaxoSmithKline, Medicines Research Centre, Hertfordshire SG1 2NY, UK
| | - Danuta E Mossakowska
- Discovery Partnerships with Academia, GlaxoSmithKline, Medicines Research Centre, Hertfordshire SG1 2NY, UK.,Malopolska Centre of Biotechnology, Jagiellonian University, 30-348 Krakow, Poland
| | - David H Drewry
- Department of Chemical Biology, GlaxoSmithKline, Research Triangle Park, NC 27709-3398, USA
| | - William J Zuercher
- Department of Chemical Biology, GlaxoSmithKline, Research Triangle Park, NC 27709-3398, USA.,SGC Center for Chemical Biology, UNC, Eshelman School of Pharmacy, Chapel Hill, NC 27599, USA
| | - Charles A Thornton
- Department of Neurology, University of Rochester Medical Center, Rochester, NY 14642-0001, USA
| | - Gerard Drewes
- Cellzome GmbH, Molecular Discovery Research, GlaxoSmithKline, Meyerhofstrasse 1, 61997 Heidelberg, Germany
| | - Iain Uings
- Discovery Partnerships with Academia, GlaxoSmithKline, Medicines Research Centre, Hertfordshire SG1 2NY, UK
| | - Christopher J Hayes
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - J David Brook
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK.
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18
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Alexander MS, Hightower RM, Reid AL, Bennett AH, Iyer L, Slonim DK, Saha M, Kawahara G, Kunkel LM, Kopin AS, Gupta VA, Kang PB, Draper I. hnRNP L is essential for myogenic differentiation and modulates myotonic dystrophy pathologies. Muscle Nerve 2021; 63:928-940. [PMID: 33651408 DOI: 10.1002/mus.27216] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 02/25/2021] [Accepted: 02/28/2021] [Indexed: 12/12/2022]
Abstract
INTRODUCTION RNA-binding proteins (RBPs) play an important role in skeletal muscle development and disease by regulating RNA splicing. In myotonic dystrophy type 1 (DM1), the RBP MBNL1 (muscleblind-like) is sequestered by toxic CUG repeats, leading to missplicing of MBNL1 targets. Mounting evidence from the literature has implicated other factors in the pathogenesis of DM1. Herein we sought to evaluate the functional role of the splicing factor hnRNP L in normal and DM1 muscle cells. METHODS Co-immunoprecipitation assays using hnRNPL and MBNL1 expression constructs and splicing profiling in normal and DM1 muscle cell lines were performed. Zebrafish morpholinos targeting hnrpl and hnrnpl2 were injected into one-cell zebrafish for developmental and muscle analysis. In human myoblasts downregulation of hnRNP L was achieved with shRNAi. Ascochlorin administration to DM1 myoblasts was performed and expression of the CUG repeats, DM1 splicing biomarkers, and hnRNP L expression levels were evaluated. RESULTS Using DM1 patient myoblast cell lines we observed the formation of abnormal hnRNP L nuclear foci within and outside the expanded CUG repeats, suggesting a role for this factor in DM1 pathology. We showed that the antiviral and antitumorigenic isoprenoid compound ascochlorin increased MBNL1 and hnRNP L expression levels. Drug treatment of DM1 muscle cells with ascochlorin partially rescued missplicing of established early biomarkers of DM1 and improved the defective myotube formation displayed by DM1 muscle cells. DISCUSSION Together, these studies revealed that hnRNP L can modulate DM1 pathologies and is a potential therapeutic target.
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Affiliation(s)
- Matthew S Alexander
- Division of Neurology, Department of Pediatrics, University of Alabama at Birmingham and Children's of Alabama, Birmingham, Alabama, USA.,Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Civitan International Research Center, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Rylie M Hightower
- Division of Neurology, Department of Pediatrics, University of Alabama at Birmingham and Children's of Alabama, Birmingham, Alabama, USA.,Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Andrea L Reid
- Division of Neurology, Department of Pediatrics, University of Alabama at Birmingham and Children's of Alabama, Birmingham, Alabama, USA
| | - Alexis H Bennett
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Lakshmanan Iyer
- Department of Neuroscience, Tufts University, Boston, Massachusetts, USA
| | - Donna K Slonim
- Department of Computer Science, Tufts University, Medford, Massachusetts, USA
| | - Madhurima Saha
- Division of Pediatric Neurology, Department of Pediatrics, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Genri Kawahara
- Department of Pathophysiology, Tokyo Medical University, Tokyo, Japan
| | - Louis M Kunkel
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts, USA.,Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA.,Harvard Stem Cell Institute, Cambridge, Massachusetts, USA.,The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Alan S Kopin
- Department of Medicine, Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts, USA
| | - Vandana A Gupta
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Peter B Kang
- Division of Pediatric Neurology, Department of Pediatrics, University of Florida College of Medicine, Gainesville, Florida, USA.,Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, Gainesville, Florida, USA.,Department of Neurology, University of Florida College of Medicine, Gainesville, Florida, USA.,Genetics Institute and Myology Institute, University of Florida, Gainesville, Florida, USA.,Paul and Sheila Wellstone Muscular Dystrophy Center, University of Minnesota Medical School, Minneapolis, Minnesota, USA.,Neurology Department, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Isabelle Draper
- Department of Medicine, Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts, USA
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19
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Yokoyama S, Ohno Y, Egawa T, Ohashi K, Ito R, Ortuste Quiroga HP, Yamashita T, Goto K. MBNL1-Associated Mitochondrial Dysfunction and Apoptosis in C2C12 Myotubes and Mouse Skeletal Muscle. Int J Mol Sci 2020; 21:ijms21176376. [PMID: 32887414 PMCID: PMC7503908 DOI: 10.3390/ijms21176376] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/27/2020] [Accepted: 08/31/2020] [Indexed: 01/06/2023] Open
Abstract
We explored the interrelationship between a tissue-specific alternative splicing factor muscleblind-like 1 (MBNL1) and peroxisome proliferator-activated receptor-γ coactivator 1-α (PGC-1α), B-cell lymphoma 2 (Bcl-2) or Bcl-2-associated X protein (Bax) in C2C12 myotubes and mouse skeletal muscle to investigate a possible physiological role of MBNL1 in mitochondrial-associated apoptosis of skeletal muscle. Expression level of PGC-1α and mitochondrial membrane potential evaluated by the fluorescence ratio of JC-1 aggregate to monomer in C2C12 myotubes were suppressed by knockdown of MBNL1. Conversely, the ratio of Bax to Bcl-2 as well as the apoptotic index in C2C12 myotubes was increased by MBNL1 knockdown. In plantaris muscle, on the other hand, not only the minimum muscle fiber diameter but also the expression level of MBNL1 and PGC-1α in of 100-week-old mice were significantly lower than that of 10-week-old mice. Furthermore, the ratio of Bax to Bcl-2 in mouse plantaris muscle was increased by aging. These results suggest that MBNL1 may play a key role in aging-associated muscle atrophy accompanied with mitochondrial dysfunction and apoptosis via mediating PGC-1α expression in skeletal muscle.
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Affiliation(s)
- Shingo Yokoyama
- Laboratory of Physiology, School of Health Science, Toyohashi SOZO University, Toyohashi 440-8511, Japan; (S.Y.); (K.O.)
| | - Yoshitaka Ohno
- Faculty of Rehabilitation and Care, Seijoh University, Tokai 476-8588, Japan;
- Department of Physiology, Graduate School of Health Science, Toyohashi SOZO University, Toyohashi 440-8511, Japan; (T.E.); (R.I.); (H.P.O.Q.); (T.Y.)
| | - Tatsuro Egawa
- Department of Physiology, Graduate School of Health Science, Toyohashi SOZO University, Toyohashi 440-8511, Japan; (T.E.); (R.I.); (H.P.O.Q.); (T.Y.)
- Laboratory of Sports and Exercise Medicine, Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8511, Japan
| | - Kazuya Ohashi
- Laboratory of Physiology, School of Health Science, Toyohashi SOZO University, Toyohashi 440-8511, Japan; (S.Y.); (K.O.)
| | - Rika Ito
- Department of Physiology, Graduate School of Health Science, Toyohashi SOZO University, Toyohashi 440-8511, Japan; (T.E.); (R.I.); (H.P.O.Q.); (T.Y.)
| | - Huascar Pedro Ortuste Quiroga
- Department of Physiology, Graduate School of Health Science, Toyohashi SOZO University, Toyohashi 440-8511, Japan; (T.E.); (R.I.); (H.P.O.Q.); (T.Y.)
| | - Tomohiro Yamashita
- Department of Physiology, Graduate School of Health Science, Toyohashi SOZO University, Toyohashi 440-8511, Japan; (T.E.); (R.I.); (H.P.O.Q.); (T.Y.)
| | - Katsumasa Goto
- Laboratory of Physiology, School of Health Science, Toyohashi SOZO University, Toyohashi 440-8511, Japan; (S.Y.); (K.O.)
- Department of Physiology, Graduate School of Health Science, Toyohashi SOZO University, Toyohashi 440-8511, Japan; (T.E.); (R.I.); (H.P.O.Q.); (T.Y.)
- Correspondence:
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20
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Wansink DG, Gourdon G, van Engelen BGM, Schoser B. 248th ENMC International Workshop: Myotonic dystrophies: Molecular approaches for clinical purposes, framing a European molecular research network, Hoofddorp, the Netherlands, 11-13 October 2019. Neuromuscul Disord 2020; 30:521-531. [PMID: 32417002 DOI: 10.1016/j.nmd.2020.03.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 03/19/2020] [Indexed: 01/11/2023]
Affiliation(s)
- Derick G Wansink
- Radboud Institute for Molecular Life Sciences, Department of Cell Biology, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
| | - Geneviève Gourdon
- Inserm UMR 974, Sorbonne Université, Centre de Recherche en Myologie, Association Institut de Myologie, 75013 Paris, France
| | - Baziel G M van Engelen
- Donders Institute for Brain, Cognition and Behaviour, Department of Neurology, Radboud University Medical Center, 6525 GC Nijmegen, the Netherlands
| | - Benedikt Schoser
- Friedrich-Baur-Institute, Department of Neurology, Ludwig-Maximilians-University, Munich, Germany.
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21
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Abstract
PURPOSE OF REVIEW This article describes the clinical features, pathogenesis, prevalence, diagnosis, and management of myotonic dystrophy type 1 and myotonic dystrophy type 2. RECENT FINDINGS The prevalence of myotonic dystrophy type 1 is better understood than the prevalence of myotonic dystrophy type 2, and new evidence indicates that the risk of cancer is increased in patients with the myotonic dystrophies. In addition, descriptions of the clinical symptoms and relative risks of comorbidities such as cardiac arrhythmias associated with myotonic dystrophy type 1 have been improved. SUMMARY Myotonic dystrophy type 1 and myotonic dystrophy type 2 are both characterized by progressive muscle weakness, early-onset cataracts, and myotonia. However, both disorders have multisystem manifestations that require a comprehensive management plan. While no disease-modifying therapies have yet been identified, advances in therapeutic development have a promising future.
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22
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Abstract
Mutant DMPK transcripts containing expanded CUG repeats (CUGexp) are retained within the nucleus of myotonic dystrophy type 1 (DM1) cells as discrete foci. Nuclear CUGexp-RNA foci that sequester MBNL1 splicing factor represent a hallmark of this RNA dominant disease caused by the expression of expanded microsatellite repeats. Here we described fluorescent in situ hybridization (FISH) techniques to detect either RNA containing CUG expansion or DMPK transcripts in human DM1 or WT cells. In addition, we propose a combined FISH/immunofluorescence protocol to visualize the colocalization of MBNL1 with CUGexp-RNA foci in DM1 cells.
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Affiliation(s)
- Arnaud F Klein
- Centre de Recherche en Myologie, Sorbonne Univeristé, Paris, France
- Centre de Recherche en Myologie, Inserm, Paris, France
- Association Institut de Myologie, Paris, France
| | - Ludovic Arandel
- Centre de Recherche en Myologie, Sorbonne Univeristé, Paris, France
- Centre de Recherche en Myologie, Inserm, Paris, France
- Association Institut de Myologie, Paris, France
| | - Joelle Marie
- Centre de Recherche en Myologie, Sorbonne Univeristé, Paris, France
- Centre de Recherche en Myologie, Inserm, Paris, France
- Association Institut de Myologie, Paris, France
| | - Denis Furling
- Centre de Recherche en Myologie, Sorbonne Univeristé, Paris, France.
- Centre de Recherche en Myologie, Inserm, Paris, France.
- Association Institut de Myologie, Paris, France.
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23
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Dosage effect of multiple genes accounts for multisystem disorder of myotonic dystrophy type 1. Cell Res 2019; 30:133-145. [PMID: 31853004 PMCID: PMC7015062 DOI: 10.1038/s41422-019-0264-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 11/09/2019] [Indexed: 12/19/2022] Open
Abstract
Multisystem manifestations in myotonic dystrophy type 1 (DM1) may be due to dosage reduction in multiple genes induced by aberrant expansion of CTG repeats in DMPK, including DMPK, its neighboring genes (SIX5 or DMWD) and downstream MBNL1. However, direct evidence is lacking. Here, we develop a new strategy to generate mice carrying multigene heterozygous mutations to mimic dosage reduction in one step by injection of haploid embryonic stem cells with mutant Dmpk, Six5 and Mbnl1 into oocytes. The triple heterozygous mutant mice exhibit adult-onset DM1 phenotypes. With the additional mutation in Dmwd, the quadruple heterozygous mutant mice recapitulate many major manifestations in congenital DM1. Moreover, muscle stem cells in both models display reduced stemness, providing a unique model for screening small molecules for treatment of DM1. Our results suggest that the complex symptoms of DM1 result from the reduced dosage of multiple genes.
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24
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Martier R, Sogorb-Gonzalez M, Stricker-Shaver J, Hübener-Schmid J, Keskin S, Klima J, Toonen LJ, Juhas S, Juhasova J, Ellederova Z, Motlik J, Haas E, van Deventer S, Konstantinova P, Nguyen HP, Evers MM. Development of an AAV-Based MicroRNA Gene Therapy to Treat Machado-Joseph Disease. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2019; 15:343-358. [PMID: 31828177 PMCID: PMC6889651 DOI: 10.1016/j.omtm.2019.10.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 10/22/2019] [Indexed: 01/06/2023]
Abstract
Spinocerebellar ataxia type 3 (SCA3), or Machado-Joseph disease (MJD), is a progressive neurodegenerative disorder caused by a CAG expansion in the ATXN3 gene. The expanded CAG repeat is translated into a prolonged polyglutamine repeat in the ataxin-3 protein and accumulates within inclusions, acquiring toxic properties, which results in degeneration of the cerebellum and brain stem. In the current study, a non-allele-specific ATXN3 silencing approach was investigated using artificial microRNAs engineered to target various regions of the ATXN3 gene (miATXN3). The miATXN3 candidates were screened in vitro based on their silencing efficacy on a luciferase (Luc) reporter co-expressing ATXN3. The three best miATXN3 candidates were further tested for target engagement and potential off-target activity in induced pluripotent stem cells (iPSCs) differentiated into frontal brain-like neurons and in a SCA3 knockin mouse model. Besides a strong reduction of ATXN3 mRNA and protein, small RNA sequencing revealed efficient guide strand processing without passenger strands being produced. We used different methods to predict alteration of off-target genes upon AAV5-miATXN3 treatment and found no evidence for unwanted effects. Furthermore, we demonstrated in a large animal model, the minipig, that intrathecal delivery of AAV5 can transduce the main areas affected in SCA3 patients. These results proved a strong basis to move forward to investigate distribution, efficacy, and safety of AAV5-miATXN3 in large animals.
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Affiliation(s)
- Raygene Martier
- Department of Research & Development, uniQure Biopharma B.V., Amsterdam, the Netherlands.,Department of Gastroenterology and Hepatology, Leiden University Medical Center, Leiden, the Netherlands
| | - Marina Sogorb-Gonzalez
- Department of Research & Development, uniQure Biopharma B.V., Amsterdam, the Netherlands.,Department of Gastroenterology and Hepatology, Leiden University Medical Center, Leiden, the Netherlands
| | - Janice Stricker-Shaver
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, Germany
| | | | - Sonay Keskin
- Department of Research & Development, uniQure Biopharma B.V., Amsterdam, the Netherlands
| | - Jiri Klima
- Institute of Animal Physiology and Genetics, Libechov, Czech Republic
| | - Lodewijk J Toonen
- Department of Research & Development, uniQure Biopharma B.V., Amsterdam, the Netherlands
| | - Stefan Juhas
- Institute of Animal Physiology and Genetics, Libechov, Czech Republic
| | - Jana Juhasova
- Institute of Animal Physiology and Genetics, Libechov, Czech Republic
| | - Zdenka Ellederova
- Institute of Animal Physiology and Genetics, Libechov, Czech Republic
| | - Jan Motlik
- Institute of Animal Physiology and Genetics, Libechov, Czech Republic
| | - Eva Haas
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, Germany
| | - Sander van Deventer
- Department of Research & Development, uniQure Biopharma B.V., Amsterdam, the Netherlands.,Department of Gastroenterology and Hepatology, Leiden University Medical Center, Leiden, the Netherlands
| | - Pavlina Konstantinova
- Department of Research & Development, uniQure Biopharma B.V., Amsterdam, the Netherlands
| | - Huu Phuc Nguyen
- Department of Human Genetics, Medical Faculty, Ruhr University Bochum, Bochum, Germany
| | - Melvin M Evers
- Department of Research & Development, uniQure Biopharma B.V., Amsterdam, the Netherlands
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25
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Taylor K, Sznajder LJ, Cywoniuk P, Thomas JD, Swanson MS, Sobczak K. MBNL splicing activity depends on RNA binding site structural context. Nucleic Acids Res 2019; 46:9119-9133. [PMID: 29955876 PMCID: PMC6158504 DOI: 10.1093/nar/gky565] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 06/16/2018] [Indexed: 02/02/2023] Open
Abstract
Muscleblind-like (MBNL) proteins are conserved RNA-binding factors involved in alternative splicing (AS) regulation during development. While AS is controlled by distribution of MBNL paralogs and isoforms, the affinity of these proteins for specific RNA-binding regions and their location within transcripts, it is currently unclear how RNA structure impacts MBNL-mediated AS regulation. Here, we defined the RNA structural determinants affecting MBNL-dependent AS activity using both cellular and biochemical assays. While enhanced inclusion of MBNL-regulated alternative exons is controlled by the arrangement and number of MBNL binding sites within unstructured RNA, when these sites are embedded in a RNA hairpin MBNL binds preferentially to one side of stem region. Surprisingly, binding of MBNL proteins to RNA targets did not entirely correlate with AS efficiency. Moreover, comparison of MBNL proteins revealed structure-dependent competitive behavior between the paralogs. Our results showed that the structure of targeted RNAs is a prevalent component of the mechanism of alternative splicing regulation by MBNLs.
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Affiliation(s)
- Katarzyna Taylor
- Laboratory of Gene Therapy, Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
| | - Lukasz J Sznajder
- Center for NeuroGenetics and the Genetics Institute, Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, 2033 Mowry Road, Gainesville, FL 32610, USA
| | - Piotr Cywoniuk
- Laboratory of Gene Therapy, Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
| | - James D Thomas
- Center for NeuroGenetics and the Genetics Institute, Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, 2033 Mowry Road, Gainesville, FL 32610, USA.,Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Maurice S Swanson
- Center for NeuroGenetics and the Genetics Institute, Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, 2033 Mowry Road, Gainesville, FL 32610, USA
| | - Krzysztof Sobczak
- Laboratory of Gene Therapy, Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
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26
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Lo Scrudato M, Poulard K, Sourd C, Tomé S, Klein AF, Corre G, Huguet A, Furling D, Gourdon G, Buj-Bello A. Genome Editing of Expanded CTG Repeats within the Human DMPK Gene Reduces Nuclear RNA Foci in the Muscle of DM1 Mice. Mol Ther 2019; 27:1372-1388. [PMID: 31253581 PMCID: PMC6697452 DOI: 10.1016/j.ymthe.2019.05.021] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 05/22/2019] [Accepted: 05/29/2019] [Indexed: 12/21/2022] Open
Abstract
Myotonic dystrophy type 1 (DM1) is caused by a CTG repeat expansion located in the 3' UTR of the DMPK gene. Expanded DMPK transcripts aggregate into nuclear foci and alter the function of RNA-binding proteins, leading to defects in the alternative splicing of numerous pre-mRNAs. To date, there is no curative treatment for DM1. Here we investigated a gene-editing strategy using the CRISPR-Cas9 system from Staphylococcus aureus (Sa) to delete the CTG repeats in the human DMPK locus. Co-expression of SaCas9 and selected pairs of single-guide RNAs (sgRNAs) in cultured DM1 patient-derived muscle line cells carrying 2,600 CTG repeats resulted in targeted DNA deletion, ribonucleoprotein foci disappearance, and correction of splicing abnormalities in various transcripts. Furthermore, a single intramuscular injection of recombinant AAV vectors expressing CRISPR-SaCas9 components in the tibialis anterior muscle of DMSXL (myotonic dystrophy mouse line carrying the human DMPK gene with >1,000 CTG repeats) mice decreased the number of pathological RNA foci in myonuclei. These results establish the proof of concept that genome editing of a large trinucleotide expansion is feasible in muscle and may represent a useful strategy to be further developed for the treatment of myotonic dystrophy.
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Affiliation(s)
- Mirella Lo Scrudato
- Genethon, INSERM UMR_S951, Univ Evry, Université Paris Saclay, 91000 Evry, France
| | - Karine Poulard
- Genethon, INSERM UMR_S951, Univ Evry, Université Paris Saclay, 91000 Evry, France
| | - Célia Sourd
- Genethon, INSERM UMR_S951, Univ Evry, Université Paris Saclay, 91000 Evry, France
| | - Stéphanie Tomé
- INSERM UMR 1163, Institut Imagine, Université Paris Descartes-Sorbonne Paris Cité, 75015 Paris, France
| | - Arnaud F Klein
- INSERM, Association Institut de Myologie, Centre de Recherche en Myologie, Sorbonne Université, 75013 Paris, France
| | - Guillaume Corre
- Genethon, INSERM UMR_S951, Univ Evry, Université Paris Saclay, 91000 Evry, France
| | - Aline Huguet
- INSERM UMR 1163, Institut Imagine, Université Paris Descartes-Sorbonne Paris Cité, 75015 Paris, France
| | - Denis Furling
- INSERM, Association Institut de Myologie, Centre de Recherche en Myologie, Sorbonne Université, 75013 Paris, France
| | - Geneviève Gourdon
- INSERM UMR 1163, Institut Imagine, Université Paris Descartes-Sorbonne Paris Cité, 75015 Paris, France
| | - Ana Buj-Bello
- Genethon, INSERM UMR_S951, Univ Evry, Université Paris Saclay, 91000 Evry, France.
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27
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Hale MA, Richardson JI, Day RC, McConnell OL, Arboleda J, Wang ET, Berglund JA. An engineered RNA binding protein with improved splicing regulation. Nucleic Acids Res 2019; 46:3152-3168. [PMID: 29309648 PMCID: PMC5888374 DOI: 10.1093/nar/gkx1304] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 12/19/2017] [Indexed: 01/08/2023] Open
Abstract
The muscleblind-like (MBNL) family of proteins are key developmental regulators of alternative splicing. Sequestration of MBNL proteins by expanded CUG/CCUG repeat RNA transcripts is a major pathogenic mechanism in the neuromuscular disorder myotonic dystrophy (DM). MBNL1 contains four zinc finger (ZF) motifs that form two tandem RNA binding domains (ZF1-2 and ZF3-4) which each bind YGCY RNA motifs. In an effort to determine the differences in function between these domains, we designed and characterized synthetic MBNL proteins with duplicate ZF1-2 or ZF3-4 domains, referred to as MBNL-AA and MBNL-BB, respectively. Analysis of splicing regulation revealed that MBNL-AA had up to 5-fold increased splicing activity while MBNL-BB had 4-fold decreased activity compared to a MBNL protein with the canonical arrangement of zinc finger domains. RNA binding analysis revealed that the variations in splicing activity are due to differences in RNA binding specificities between the two ZF domains rather than binding affinity. Our findings indicate that ZF1-2 drives splicing regulation via recognition of YGCY RNA motifs while ZF3-4 acts as a general RNA binding domain. Our studies suggest that synthetic MBNL proteins with improved or altered splicing activity have the potential to be used as both tools for investigating splicing regulation and protein therapeutics for DM and other microsatellite diseases.
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Affiliation(s)
- Melissa A Hale
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL 32610, USA.,Center for NeuroGenetics, University of Florida, Gainesville, FL 32610, USA
| | - Jared I Richardson
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL 32610, USA.,Center for NeuroGenetics, University of Florida, Gainesville, FL 32610, USA
| | - Ryan C Day
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL 32610, USA.,Center for NeuroGenetics, University of Florida, Gainesville, FL 32610, USA
| | - Ona L McConnell
- Center for NeuroGenetics, University of Florida, Gainesville, FL 32610, USA.,Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL 32610, USA
| | - Juan Arboleda
- Center for NeuroGenetics, University of Florida, Gainesville, FL 32610, USA.,Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL 32610, USA
| | - Eric T Wang
- Center for NeuroGenetics, University of Florida, Gainesville, FL 32610, USA.,Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL 32610, USA
| | - J Andrew Berglund
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL 32610, USA.,Center for NeuroGenetics, University of Florida, Gainesville, FL 32610, USA
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28
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Hale MA, Johnson NE, Berglund JA. Repeat-associated RNA structure and aberrant splicing. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:194405. [PMID: 31323433 DOI: 10.1016/j.bbagrm.2019.07.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 07/11/2019] [Accepted: 07/12/2019] [Indexed: 12/13/2022]
Abstract
Over 30 hereditary disorders attributed to the expansion of microsatellite repeats have been identified. Despite variant nucleotide content, number of consecutive repeats, and different locations in the genome, many of these diseases have pathogenic RNA gain-of-function mechanisms. The repeat-containing RNAs can form structures in vitro predicted to contribute to the disease through assembly of intracellular RNA aggregates termed foci. The expanded repeat RNAs within these foci sequester RNA binding proteins (RBPs) with important roles in the regulation of RNA metabolism, most notably alternative splicing (AS). These deleterious interactions lead to downstream alterations in transcriptome-wide AS directly linked with disease symptoms. This review summarizes existing knowledge about the association between the repeat RNA structures and RBPs as well as the resulting aberrant AS patterns, specifically in the context of myotonic dystrophy. The connection between toxic, structured RNAs and dysregulation of AS in other repeat expansion diseases is also discussed. This article is part of a Special Issue entitled: RNA structure and splicing regulation edited by Francisco Baralle, Ravindra Singh and Stefan Stamm.
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Affiliation(s)
- Melissa A Hale
- Department of Neurology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Nicholas E Johnson
- Department of Neurology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - J Andrew Berglund
- The RNA Institute, Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, USA.
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29
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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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30
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Babačić H, Mehta A, Merkel O, Schoser B. CRISPR-cas gene-editing as plausible treatment of neuromuscular and nucleotide-repeat-expansion diseases: A systematic review. PLoS One 2019; 14:e0212198. [PMID: 30794581 PMCID: PMC6386526 DOI: 10.1371/journal.pone.0212198] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 01/29/2019] [Indexed: 12/26/2022] Open
Abstract
INTRODUCTION The system of clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated proteins (cas) is a new technology that allows easier manipulation of the genome. Its potential to edit genes opened a new door in treatment development for incurable neurological monogenic diseases (NMGDs). The aim of this systematic review was to summarise the findings on the current development of CRISPR-cas for therapeutic purposes in the most frequent NMGDs and provide critical assessment. METHODS AND DATA ACQUISITION We searched the MEDLINE and EMBASE databases, looking for original studies on the use of CRISPR-cas to edit pathogenic variants in models of the most frequent NMGDs, until end of 2017. We included all the studies that met the following criteria: 1. Peer-reviewed study report with explicitly described experimental designs; 2. In vitro, ex vivo, or in vivo study using human or other animal biological systems (including cells, tissues, organs, organisms); 3. focusing on CRISPR as the gene-editing method of choice; and 5. featured at least one NMGD. RESULTS We obtained 404 papers from MEDLINE and 513 from EMBASE. After removing the duplicates, we screened 490 papers by title and abstract and assessed them for eligibility. After reading 50 full-text papers, we finally selected 42 for the review. DISCUSSION Here we give a systematic summary on the preclinical development of CRISPR-cas for therapeutic purposes in NMGDs. Furthermore, we address the clinical interpretability of the findings, giving a comprehensive overview of the current state of the art. Duchenne's muscular dystrophy (DMD) paves the way forward, with 26 out of 42 studies reporting different strategies on DMD gene editing in different models of the disease. Most of the strategies aimed for permanent exon skipping by deletion with CRISPR-cas. Successful silencing of the mHTT gene with CRISPR-cas led to successful reversal of the neurotoxic effects in the striatum of mouse models of Huntington's disease. Many other strategies have been explored, including epigenetic regulation of gene expression, in cellular and animal models of: myotonic dystrophy, Fraxile X syndrome, ataxias, and other less frequent dystrophies. Still, before even considering the clinical application of CRISPR-cas, three major bottlenecks need to be addressed: efficacy, safety, and delivery of the systems. This requires a collaborative approach in the research community, while having ethical considerations in mind.
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Affiliation(s)
- Haris Babačić
- Friedrich Baur Institute, Department of Neurology, Ludwig-Maximilians-University of Munich, Munich, Germany
- * E-mail: (BS); (HB)
| | - Aditi Mehta
- Faculty of Pharmacy, Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Olivia Merkel
- Faculty of Pharmacy, Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Benedikt Schoser
- Friedrich Baur Institute, Department of Neurology, Ludwig-Maximilians-University of Munich, Munich, Germany
- * E-mail: (BS); (HB)
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31
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Vatsavayai SC, Nana AL, Yokoyama JS, Seeley WW. C9orf72-FTD/ALS pathogenesis: evidence from human neuropathological studies. Acta Neuropathol 2019; 137:1-26. [PMID: 30368547 DOI: 10.1007/s00401-018-1921-0] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 10/16/2018] [Accepted: 10/16/2018] [Indexed: 12/11/2022]
Abstract
What are the most important and treatable pathogenic mechanisms in C9orf72-FTD/ALS? Model-based efforts to address this question are forging ahead at a blistering pace, often with conflicting results. But what does the human neuropathological literature reveal? Here, we provide a critical review of the human studies to date, seeking to highlight key gaps or uncertainties in our knowledge. First, we engage the C9orf72-specific mechanisms, including C9orf72 haploinsufficiency, repeat RNA foci, and dipeptide repeat protein inclusions. We then turn to some of the most prominent C9orf72-associated features, such as TDP-43 loss-of-function, TDP-43 aggregation, and nuclear transport defects. Finally, we review potential disease-modifying epigenetic and genetic factors and the natural history of the disease across the lifespan. Throughout, we emphasize the importance of anatomical precision when studying how candidate mechanisms relate to neuronal, regional, and behavioral findings. We further highlight methodological approaches that may help address lingering knowledge gaps and uncertainties, as well as other logical next steps for the field. We conclude that anatomically oriented human neuropathological studies have a critical role to play in guiding this fast-moving field toward effective new therapies.
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Affiliation(s)
- Sarat C Vatsavayai
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, USA
| | - Alissa L Nana
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, USA
| | - Jennifer S Yokoyama
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, USA
| | - William W Seeley
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, USA.
- Department of Pathology, University of California, San Francisco, Box 1207, San Francisco, CA, 94143-1207, USA.
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32
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Myotonic Dystrophy: an RNA Toxic Gain of Function Tauopathy? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1184:207-216. [PMID: 32096040 DOI: 10.1007/978-981-32-9358-8_17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Myotonic dystrophies (DM) are rare inherited neuromuscular disorders linked to microsatellite unstable expansions in non-coding regions of ubiquitously expressed genes. The DMPK and ZNF9/CNBP genes which mutations are responsible for DM1 and DM2 respectively. DM are multisystemic disorders with brain affection and cognitive deficits. Brain lesions consisting of neurofibrillary tangles are often observed in DM1 and DM2 brain. Neurofibrillary tangles (NFT) made of aggregates of hyper and abnormally phosphorylated isoforms of Tau proteins are neuropathological lesions common to more than 20 neurological disorders globally referred to as Tauopathies. Although NFT are observed in DM1 and DM2 brain, the question of whether DM1 and DM2 are Tauopathies remains a matter of debate. In the present review, several pathophysiological processes including, missplicing, nucleocytoplasmic transport disruption, RAN translation which are common mechanisms implicated in neurodegenerative diseases will be described. Together, these processes including the missplicing of Tau are providing evidence that DM1 and DM2 are not solely muscular diseases but that their brain affection component share many similarities with Tauopathies and other neurodegenerative diseases. Understanding DM1 and DM2 pathophysiology is therefore valuable to more globally understand other neurodegenerative diseases such as Tauopathies but also frontotemporal lobar neurodegeneration and amyotrophic lateral sclerosis.
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33
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Souidi A, Zmojdzian M, Jagla K. Dissecting Pathogenetic Mechanisms and Therapeutic Strategies in Drosophila Models of Myotonic Dystrophy Type 1. Int J Mol Sci 2018; 19:E4104. [PMID: 30567354 PMCID: PMC6321436 DOI: 10.3390/ijms19124104] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Revised: 12/08/2018] [Accepted: 12/13/2018] [Indexed: 12/16/2022] Open
Abstract
Myotonic dystrophy type 1 (DM1), the most common cause of adult-onset muscular dystrophy, is autosomal dominant, multisystemic disease with characteristic symptoms including myotonia, heart defects, cataracts and testicular atrophy. DM1 disease is being successfully modelled in Drosophila allowing to identify and validate new pathogenic mechanisms and potential therapeutic strategies. Here we provide an overview of insights gained from fruit fly DM1 models, either: (i) fundamental with particular focus on newly identified gene deregulations and their link with DM1 symptoms; or (ii) applied via genetic modifiers and drug screens to identify promising therapeutic targets.
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Affiliation(s)
- Anissa Souidi
- GReD, INSERM U1103, CNRS, UMR6293, University of Clermont Auvergne, 28 Place Henri Dunant, 63000 Clermont-Ferrand, France.
| | - Monika Zmojdzian
- GReD, INSERM U1103, CNRS, UMR6293, University of Clermont Auvergne, 28 Place Henri Dunant, 63000 Clermont-Ferrand, France.
| | - Krzysztof Jagla
- GReD, INSERM U1103, CNRS, UMR6293, University of Clermont Auvergne, 28 Place Henri Dunant, 63000 Clermont-Ferrand, France.
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34
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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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Kalra S, Montanaro F, Denning C. Can Human Pluripotent Stem Cell-Derived Cardiomyocytes Advance Understanding of Muscular Dystrophies? J Neuromuscul Dis 2018; 3:309-332. [PMID: 27854224 PMCID: PMC5123622 DOI: 10.3233/jnd-150133] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Muscular dystrophies (MDs) are clinically and molecularly a highly heterogeneous group of single-gene disorders that primarily affect striated muscles. Cardiac disease is present in several MDs where it is an important contributor to morbidity and mortality. Careful monitoring of cardiac issues is necessary but current management of cardiac involvement does not effectively protect from disease progression and cardiac failure. There is a critical need to gain new knowledge on the diverse molecular underpinnings of cardiac disease in MDs in order to guide cardiac treatment development and assist in reaching a clearer consensus on cardiac disease management in the clinic. Animal models are available for the majority of MDs and have been invaluable tools in probing disease mechanisms and in pre-clinical screens. However, there are recognized genetic, physiological, and structural differences between human and animal hearts that impact disease progression, manifestation, and response to pharmacological interventions. Therefore, there is a need to develop parallel human systems to model cardiac disease in MDs. This review discusses the current status of cardiomyocytes (CMs) derived from human induced pluripotent stem cells (hiPSC) to model cardiac disease, with a focus on Duchenne muscular dystrophy (DMD) and myotonic dystrophy (DM1). We seek to provide a balanced view of opportunities and limitations offered by this system in elucidating disease mechanisms pertinent to human cardiac physiology and as a platform for treatment development or refinement.
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Affiliation(s)
- Spandan Kalra
- Department of Stem Cell Biology, Centre for Biomolecular Sciences, University of Nottingham, UK
| | - Federica Montanaro
- Dubowitz Neuromuscular Centre, Department of Molecular Neurosciences, University College London - Institute of Child Health, London, UK
| | - Chris Denning
- Department of Stem Cell Biology, Centre for Biomolecular Sciences, University of Nottingham, UK
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Nakka K, Ghigna C, Gabellini D, Dilworth FJ. Diversification of the muscle proteome through alternative splicing. Skelet Muscle 2018; 8:8. [PMID: 29510724 PMCID: PMC5840707 DOI: 10.1186/s13395-018-0152-3] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 02/15/2018] [Indexed: 12/16/2022] Open
Abstract
Background Skeletal muscles express a highly specialized proteome that allows the metabolism of energy sources to mediate myofiber contraction. This muscle-specific proteome is partially derived through the muscle-specific transcription of a subset of genes. Surprisingly, RNA sequencing technologies have also revealed a significant role for muscle-specific alternative splicing in generating protein isoforms that give specialized function to the muscle proteome. Main body In this review, we discuss the current knowledge with respect to the mechanisms that allow pre-mRNA transcripts to undergo muscle-specific alternative splicing while identifying some of the key trans-acting splicing factors essential to the process. The importance of specific splicing events to specialized muscle function is presented along with examples in which dysregulated splicing contributes to myopathies. Though there is now an appreciation that alternative splicing is a major contributor to proteome diversification, the emergence of improved “targeted” proteomic methodologies for detection of specific protein isoforms will soon allow us to better appreciate the extent to which alternative splicing modifies the activity of proteins (and their ability to interact with other proteins) in the skeletal muscle. In addition, we highlight a continued need to better explore the signaling pathways that contribute to the temporal control of trans-acting splicing factor activity to ensure specific protein isoforms are expressed in the proper cellular context. Conclusions An understanding of the signal-dependent and signal-independent events driving muscle-specific alternative splicing has the potential to provide us with novel therapeutic strategies to treat different myopathies. Electronic supplementary material The online version of this article (10.1186/s13395-018-0152-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kiran Nakka
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada
| | - Claudia Ghigna
- Istituto di Genetica Molecolare-Consiglio Nazionale delle Ricerche (IGM-CNR), Pavia, Italy
| | - Davide Gabellini
- Unit of Gene Expression and Muscular Dystrophy, Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, DIBIT2, 5A3-44, via Olgettina 58, 20132, Milan, Italy.
| | - F Jeffrey Dilworth
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada. .,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada. .,Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, 501 Smyth Rd, Mailbox 511, Ottawa, ON, K1H 8L6, Canada.
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Martí E. RNA toxicity induced by expanded CAG repeats in Huntington's disease. Brain Pathol 2018; 26:779-786. [PMID: 27529325 DOI: 10.1111/bpa.12427] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 06/09/2016] [Indexed: 02/03/2023] Open
Abstract
Huntington's disease (HD) belongs to the group of inherited polyglutamine (PolyQ) diseases caused by an expanded CAG repeat in the coding region of the Huntingtin (HTT) gene that results in an elongated polyQ stretch. Abnormal function and aggregation of the mutant protein has been typically delineated as the main molecular cause underlying disease development. However, the most recent advances have revealed novel pathogenic pathways directly dependent on an RNA toxic gain-of-function. Expanded CAG repeats within exon 1 of the HTT mRNA induce toxicity through mechanisms involving, at least in part, gene expression perturbations. This has important implications not only for basic and translational research in HD, but also for other types of diseases carrying the expanded CAG in other genes, which likely share pathogenic aspects. Here I will review the evidence and mechanisms underlying RNA toxicity in CAG repeat expansions, with particular focus on HD. These comprise abnormal subcellular localization of the transcripts containing the expanded CAG repeats; sequestration of several types of proteins by the expanded CAG repeat which results in defects of alternative splicing events and gene expression; and aberrant biogenesis and detrimental activity of small CAG repeated RNAs (sCAG) that produce altered gene silencing. Although these altered pathways have been detected in HD models, their contribution to disease development and progress requires further study.
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Affiliation(s)
- Eulàlia Martí
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Dr. Aiguader 88, Barcelona, 08003, Spain.,Universitat Pompeu Fabra (UPF), Barcelona, Spain.,Institut Hospital del Mar d'Investigacions Mediques (IMIM), Barcelona, 08003, Spain.,Centro de Investigacion Biomedica en Red (CIBERESP), Madrid, Spain
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Deregulation of RNA Metabolism in Microsatellite Expansion Diseases. ADVANCES IN NEUROBIOLOGY 2018; 20:213-238. [PMID: 29916021 DOI: 10.1007/978-3-319-89689-2_8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
RNA metabolism impacts different steps of mRNA life cycle including splicing, polyadenylation, nucleo-cytoplasmic export, translation, and decay. Growing evidence indicates that defects in any of these steps lead to devastating diseases in humans. This chapter reviews the various RNA metabolic mechanisms that are disrupted in Myotonic Dystrophy-a trinucleotide repeat expansion disease-due to dysregulation of RNA-Binding Proteins. We also compare Myotonic Dystrophy to other microsatellite expansion disorders and describe how some of these mechanisms commonly exert direct versus indirect effects toward disease pathologies.
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Rinaldi C, Wood MJA. Antisense oligonucleotides: the next frontier for treatment of neurological disorders. Nat Rev Neurol 2017; 14:9-21. [PMID: 29192260 DOI: 10.1038/nrneurol.2017.148] [Citation(s) in RCA: 482] [Impact Index Per Article: 68.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Antisense oligonucleotides (ASOs) were first discovered to influence RNA processing and modulate protein expression over two decades ago; however, progress translating these agents into the clinic has been hampered by inadequate target engagement, insufficient biological activity, and off-target toxic effects. Over the years, novel chemical modifications of ASOs have been employed to address these issues. These modifications, in combination with elucidation of the mechanism of action of ASOs and improved clinical trial design, have provided momentum for the translation of ASO-based strategies into therapies. Many neurological conditions lack an effective treatment; however, as research progressively disentangles the pathogenic mechanisms of these diseases, they provide an ideal platform to test ASO-based strategies. This steady progress reached a pinnacle in the past few years with approvals of ASOs for the treatment of spinal muscular atrophy and Duchenne muscular dystrophy, which represent landmarks in a field in which disease-modifying therapies were virtually non-existent. With the rapid development of improved next-generation ASOs toward clinical application, this technology now holds the potential to have a dramatic effect on the treatment of many neurological conditions in the near future.
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Affiliation(s)
- Carlo Rinaldi
- Department of Physiology, Anatomy and Genetics, University of Oxford, Le Gros Clark Building, South Parks Road, Oxford OX1 3QX, UK
| | - Matthew J A Wood
- Department of Physiology, Anatomy and Genetics, University of Oxford, Le Gros Clark Building, South Parks Road, Oxford OX1 3QX, UK
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Konieczny P, Stepniak-Konieczna E, Taylor K, Sznajder LJ, Sobczak K. Autoregulation of MBNL1 function by exon 1 exclusion from MBNL1 transcript. Nucleic Acids Res 2017; 45:1760-1775. [PMID: 27903900 PMCID: PMC5389549 DOI: 10.1093/nar/gkw1158] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Accepted: 11/07/2016] [Indexed: 01/14/2023] Open
Abstract
Muscleblind-like proteins (MBNLs) are regulators of RNA metabolism. During tissue differentiation the level of MBNLs increases, while their functional insufficiency plays a crucial role in myotonic dystrophy (DM). Deep sequencing of RNA molecules cross-linked to immunoprecipitated protein particles (CLIP-seq) revealed that MBNL1 binds to MBNL1 exon 1 (e1) encoding both the major part of 5΄UTR and an amino-terminal region of MBNL1 protein. We tested several hypotheses regarding the possible autoregulatory function of MBNL1 binding to its own transcript. Our data indicate that MBNLs induce skipping of e1 from precursor MBNL1 mRNA and that e1 exclusion may impact transcript association with polysomes and translation. Furthermore, e1-deficient protein isoform lacking the first two zinc fingers is highly unstable and its EGFP fusion protein has severely compromised splicing activity. We also show that MBNL1 can be transcribed from three different promoters and that the transcription initiation site determines the mode of e1 regulation. Taken together, we demonstrate that MBNL proteins control steady-state levels of MBNL1 through an interaction with e1 in its precursor mRNA. Insights from our study open a new avenue in therapies against DM based on manipulation of the transcription initiation site and e1 splicing of MBNL1 mRNA.
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Affiliation(s)
- Patryk Konieczny
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
| | - Ewa Stepniak-Konieczna
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
| | - Katarzyna Taylor
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
| | - Lukasz J Sznajder
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
| | - Krzysztof Sobczak
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
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Man L, Lekovich J, Rosenwaks Z, Gerhardt J. Fragile X-Associated Diminished Ovarian Reserve and Primary Ovarian Insufficiency from Molecular Mechanisms to Clinical Manifestations. Front Mol Neurosci 2017; 10:290. [PMID: 28955201 PMCID: PMC5600956 DOI: 10.3389/fnmol.2017.00290] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 08/28/2017] [Indexed: 12/12/2022] Open
Abstract
Fragile X syndrome (FXS), is caused by a loss-of-function mutation in the FMR1 gene located on the X-chromosome, which leads to the most common cause of inherited intellectual disability in males and the leading single-gene defect associated with autism. A full mutation (FM) is represented by more than 200 CGG repeats within the FMR1 gene, resulting in FXS. A FM is inherited from women carrying a FM or a premutation (PM; 55–200 CGG repeats) allele. PM is associated with phenotypes distinct from those associated with FM. Some manifestations of the PM are unique; fragile-X-associated tremor/ataxia syndrome (FXTAS), and fragile-X-associated primary ovarian insufficiency (FXPOI), while others tend to be non-specific such as intellectual disability. In addition, women carrying a PM may suffer from subfertility or infertility. There is a need to elucidate whether the impairment of ovarian function found in PM carriers arises during the primordial germ cell (PGC) development stage, or due to a rapidly diminishing oocyte pool throughout life or even both. Due to the possibility of expansion into a FM in the next generation, and other ramifications, carrying a PM can have an enormous impact on one’s life; therefore, preconception counseling for couples carrying the PM is of paramount importance. In this review, we will elaborate on the clinical manifestations in female PM carriers and propose the definition of fragile-X-associated diminished ovarian reserve (FXDOR), then we will review recent scientific findings regarding possible mechanisms leading to FXDOR and FXPOI. Lastly, we will discuss counseling, preventative measures and interventions available for women carrying a PM regarding different aspects of their reproductive life, fertility treatment, pregnancy, prenatal testing, contraception and fertility preservation options.
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Affiliation(s)
- Limor Man
- The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell MedicineNew York, NY, United States
| | - Jovana Lekovich
- The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell MedicineNew York, NY, United States
| | - Zev Rosenwaks
- The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell MedicineNew York, NY, United States
| | - Jeannine Gerhardt
- The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell MedicineNew York, NY, United States
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Chou CC, Chang PC, Wei YC, Lee KY. Optical Mapping Approaches on Muscleblind-Like Compound Knockout Mice for Understanding Mechanistic Insights Into Ventricular Arrhythmias in Myotonic Dystrophy. J Am Heart Assoc 2017; 6:JAHA.116.005191. [PMID: 28416514 PMCID: PMC5533016 DOI: 10.1161/jaha.116.005191] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Background Cardiac arrhythmias are common causes of death in patients with myotonic dystrophy (dystrophia myotonica [DM]). Evidence shows that atrial tachyarrhythmia is an independent risk factor for sudden death; however, the relationship is unclear. Methods and Results Control wild‐type (Mbnl1+/+; Mbnl2+/+) and DM mutant (Mbnl1−/−; Mbnl2+/−) mice were generated by crossing double heterozygous knockout (Mbnl1+/−; Mbnl2+/−) mice. In vivo electrophysiological study and optical mapping technique were performed to investigate mechanisms of ventricular tachyarrhythmias. Transmission electron microscopy scanning was performed for myocardium ultrastructural analysis. DM mutant mice were more vulnerable to anesthesia medications and program electrical pacing: 2 of 12 mice had sudden apnea and cardiac arrest during premedication of general anesthesia; 9 of the remaining 10 had atrial tachycardia and/or atrioventricular block, but none of the wild‐type mice had spontaneous arrhythmias; and 9 of 10 mice had pacing‐induced ventricular tachyarrhythmias, but only 1 of 14 of the wild‐type mice. Optical mapping studies revealed prolonged action potential duration, slower conduction velocity, and steeper conduction velocity restitution curves in the DM mutant mice than in the wild‐type group. Spatially discordant alternans was more easily inducible in DM mutant than wild‐type mice. Transmission electron microscopy showed disarranged myofibrils with enlarged vacuole‐occupying mitochondria in the DM mutant group. Conclusions This DM mutant mouse model presented with clinical myofibril ultrastructural abnormality and cardiac arrhythmias, including atrial tachyarrhythmias, atrioventricular block, and ventricular tachyarrhythmias. Optical mapping studies revealed prolonged action potential duration and slow conduction velocity in the DM mice, leading to vulnerability of spatially discordant alternans and ventricular arrhythmia induction to pacing.
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Affiliation(s)
- Chung-Chuan Chou
- Department of Cardiology, Chang Gung Memorial Hospital, Linkou, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Po-Cheng Chang
- Department of Cardiology, Chang Gung Memorial Hospital, Linkou, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yi-Chia Wei
- Department of Neurology, Chang Gung Memorial Hospital, Keelung, Taiwan
| | - Kuang-Yung Lee
- Department of Neurology, Chang Gung Memorial Hospital, Keelung, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
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Smith CA, Gutmann L. Myotonic Dystrophy Type 1 Management and Therapeutics. Curr Treat Options Neurol 2016; 18:52. [DOI: 10.1007/s11940-016-0434-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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44
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Sznajder ŁJ, Michalak M, Taylor K, Cywoniuk P, Kabza M, Wojtkowiak-Szlachcic A, Matłoka M, Konieczny P, Sobczak K. Mechanistic determinants of MBNL activity. Nucleic Acids Res 2016; 44:10326-10342. [PMID: 27733504 PMCID: PMC5137450 DOI: 10.1093/nar/gkw915] [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: 09/19/2016] [Accepted: 10/05/2016] [Indexed: 11/13/2022] Open
Abstract
Muscleblind-like (MBNL) proteins are critical RNA processing factors in development. MBNL activity is disrupted in the neuromuscular disease myotonic dystrophy type 1 (DM1), due to the instability of a non-coding microsatellite in the DMPK gene and the expression of CUG expansion (CUGexp) RNAs. Pathogenic interactions between MBNL and CUGexp RNA lead to the formation of nuclear complexes termed foci and prevent MBNL function in pre-mRNA processing. The existence of multiple MBNL genes, as well as multiple protein isoforms, raises the question of whether different MBNL proteins possess unique or redundant functions. To address this question, we coexpressed three MBNL paralogs in cells at equivalent levels and characterized both specific and redundant roles of these proteins in alternative splicing and RNA foci dynamics. When coexpressed in the same cells, MBNL1, MBNL2 and MBNL3 bind the same RNA motifs with different affinities. While MBNL1 demonstrated the highest splicing activity, MBNL3 showed the lowest. When forming RNA foci, MBNL1 is the most mobile paralog, while MBNL3 is rather static and the most densely packed on CUGexp RNA. Therefore, our results demonstrate that MBNL paralogs and gene-specific isoforms possess inherent functional differences, an outcome that could be enlisted to improve therapeutic strategies for DM1.
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Affiliation(s)
- Łukasz J Sznajder
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Michał Michalak
- Department of Molecular and Cellular Biology, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Katarzyna Taylor
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Piotr Cywoniuk
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Michał Kabza
- Department of Bioinformatics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Agnieszka Wojtkowiak-Szlachcic
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Magdalena Matłoka
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Patryk Konieczny
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Krzysztof Sobczak
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
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Identification of hepta-histidine as a candidate drug for Huntington's disease by in silico-in vitro- in vivo-integrated screens of chemical libraries. Sci Rep 2016; 6:33861. [PMID: 27653664 PMCID: PMC5032119 DOI: 10.1038/srep33861] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 09/02/2016] [Indexed: 12/13/2022] Open
Abstract
We identified drug seeds for treating Huntington’s disease (HD) by combining in vitro single molecule fluorescence spectroscopy, in silico molecular docking simulations, and in vivo fly and mouse HD models to screen for inhibitors of abnormal interactions between mutant Htt and physiological Ku70, an essential DNA damage repair protein in neurons whose function is known to be impaired by mutant Htt. From 19,468 and 3,010,321 chemicals in actual and virtual libraries, fifty-six chemicals were selected from combined in vitro-in silico screens; six of these were further confirmed to have an in vivo effect on lifespan in a fly HD model, and two chemicals exerted an in vivo effect on the lifespan, body weight and motor function in a mouse HD model. Two oligopeptides, hepta-histidine (7H) and Angiotensin III, rescued the morphological abnormalities of primary neurons differentiated from iPS cells of human HD patients. For these selected drug seeds, we proposed a possible common structure. Unexpectedly, the selected chemicals enhanced rather than inhibited Htt aggregation, as indicated by dynamic light scattering analysis. Taken together, these integrated screens revealed a new pathway for the molecular targeted therapy of HD.
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Kim YK, Yadava RS, Mandal M, Mahadevan K, Yu Q, Leitges M, Mahadevan MS. Disease Phenotypes in a Mouse Model of RNA Toxicity Are Independent of Protein Kinase Cα and Protein Kinase Cβ. PLoS One 2016; 11:e0163325. [PMID: 27657532 PMCID: PMC5033491 DOI: 10.1371/journal.pone.0163325] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 09/06/2016] [Indexed: 02/07/2023] Open
Abstract
Myotonic dystrophy type 1(DM1) is the prototype for diseases caused by RNA toxicity. RNAs from the mutant allele contain an expanded (CUG)n tract within the 3' untranslated region of the dystrophia myotonica protein kinase (DMPK) gene. The toxic RNAs affect the function of RNA binding proteins leading to sequestration of muscleblind-like (MBNL) proteins and increased levels of CELF1 (CUGBP, Elav-like family member 1). The mechanism for increased CELF1 is not very clear. One favored proposition is hyper-phosphorylation of CELF1 by Protein Kinase C alpha (PKCα) leading to increased CELF1 stability. However, most of the evidence supporting a role for PKC-α relies on pharmacological inhibition of PKC. To further investigate the role of PKCs in the pathogenesis of RNA toxicity, we generated transgenic mice with RNA toxicity that lacked both the PKCα and PKCβ isoforms. We find that these mice show similar disease progression as mice wildtype for the PKC isoforms. Additionally, the expression of CELF1 is also not affected by deficiency of PKCα and PKCβ in these RNA toxicity mice. These data suggest that disease phenotypes of these RNA toxicity mice are independent of PKCα and PKCβ.
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Affiliation(s)
- Yun K. Kim
- Department of Pathology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Ramesh S. Yadava
- Department of Pathology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Mahua Mandal
- Department of Pathology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Karunasai Mahadevan
- Department of Pathology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Qing Yu
- Department of Pathology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Michael Leitges
- The Biotechnology Centre of Oslo, University of Oslo, Oslo, Norway
| | - Mani S. Mahadevan
- Department of Pathology, University of Virginia, Charlottesville, Virginia, United States of America
- * E-mail:
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Luu LM, Nguyen L, Peng S, Lee J, Lee HY, Wong CH, Hergenrother PJ, Chan HYE, Zimmerman SC. A Potent Inhibitor of Protein Sequestration by Expanded Triplet (CUG) Repeats that Shows Phenotypic Improvements in a Drosophila Model of Myotonic Dystrophy. ChemMedChem 2016; 11:1428-35. [PMID: 27245480 DOI: 10.1002/cmdc.201600081] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 04/29/2016] [Indexed: 11/09/2022]
Abstract
Myotonic dystrophy is the most common form of adult-onset muscular dystrophy, originating in a CTG repeat expansion in the DMPK gene. The expanded CUG transcript sequesters MBNL1, a key regulator of alternative splicing, leading to the misregulation of numerous pre-mRNAs. We report an RNA-targeted agent as a possible lead compound for the treatment of myotonic dystrophy type 1 (DM1) that reveals both the promise and challenges for this type of small-molecule approach. The agent is a potent inhibitor of the MBNL1-rCUG complex with an inhibition constant (Ki ) of 25±8 nm, and is also relatively nontoxic to HeLa cells, able to dissolve nuclear foci, and correct the insulin receptor splicing defect in DM1 model cells. Moreover, treatment with this compound improves two separate disease phenotypes in a Drosophila model of DM1: adult external eye degeneration and larval crawling defect. However, the compound has a relatively low maximum tolerated dose in mice, and its cell uptake may be limited, providing insight into directions for future development.
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Affiliation(s)
- Long M Luu
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL, 61801, USA
| | - Lien Nguyen
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL, 61801, USA
| | - Shaohong Peng
- Laboratory of Drosophila Research and School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, P.R. China
| | - JuYeon Lee
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL, 61801, USA
| | - Hyang Yeon Lee
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL, 61801, USA
| | - Chun-Ho Wong
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL, 61801, USA
| | - Paul J Hergenrother
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL, 61801, USA
| | - H Y Edwin Chan
- Laboratory of Drosophila Research and School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, P.R. China.
| | - Steven C Zimmerman
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL, 61801, USA.
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48
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Bargiela A, Cerro-Herreros E, Fernandez-Costa JM, Vilchez JJ, Llamusi B, Artero R. Increased autophagy and apoptosis contribute to muscle atrophy in a myotonic dystrophy type 1 Drosophila model. Dis Model Mech 2016; 8:679-90. [PMID: 26092529 PMCID: PMC4486854 DOI: 10.1242/dmm.018127] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Muscle mass wasting is one of the most debilitating symptoms of myotonic dystrophy type 1 (DM1) disease, ultimately leading to immobility, respiratory defects, dysarthria, dysphagia and death in advanced stages of the disease. In order to study the molecular mechanisms leading to the degenerative loss of adult muscle tissue in DM1, we generated an inducible Drosophila model of expanded CTG trinucleotide repeat toxicity that resembles an adult-onset form of the disease. Heat-shock induced expression of 480 CUG repeats in adult flies resulted in a reduction in the area of the indirect flight muscles. In these model flies, reduction of muscle area was concomitant with increased apoptosis and autophagy. Inhibition of apoptosis or autophagy mediated by the overexpression of DIAP1, mTOR (also known as Tor) or muscleblind, or by RNA interference (RNAi)-mediated silencing of autophagy regulatory genes, achieved a rescue of the muscle-loss phenotype. In fact, mTOR overexpression rescued muscle size to a size comparable to that in control flies. These results were validated in skeletal muscle biopsies from DM1 patients in which we found downregulated autophagy and apoptosis repressor genes, and also in DM1 myoblasts where we found increased autophagy. These findings provide new insights into the signaling pathways involved in DM1 disease pathogenesis.
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Affiliation(s)
- Ariadna Bargiela
- Translational Genomics Group, Department of Genetics, University of Valencia, Burjassot 46100, Spain INCLIVA Health Research Institute, Valencia 46010, Spain
| | - Estefanía Cerro-Herreros
- Translational Genomics Group, Department of Genetics, University of Valencia, Burjassot 46100, Spain INCLIVA Health Research Institute, Valencia 46010, Spain
| | - Juan M Fernandez-Costa
- Translational Genomics Group, Department of Genetics, University of Valencia, Burjassot 46100, Spain
| | - Juan J Vilchez
- Neurology Section, Hospital Universitari La Fe, Valencia 46026, Spain Department of Internal Medicine, University of Valencia, Valencia 46010, Spain Centro de Investigaciones Biomedicas en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Institute Carlos III, Ministry of Economy and Competitiveness, Madrid 28049, Spain
| | | | - Ruben Artero
- Translational Genomics Group, Department of Genetics, University of Valencia, Burjassot 46100, Spain INCLIVA Health Research Institute, Valencia 46010, Spain
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49
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Gitler AD, Tsuiji H. There has been an awakening: Emerging mechanisms of C9orf72 mutations in FTD/ALS. Brain Res 2016; 1647:19-29. [PMID: 27059391 DOI: 10.1016/j.brainres.2016.04.004] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 03/30/2016] [Accepted: 04/03/2016] [Indexed: 12/13/2022]
Abstract
The discovery of C9orf72 mutations as the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) has awakened a surge of interest in deciphering how mutations in this mysterious gene cause disease and what can be done to stop it. C9orf72 harbors a hexanucleotide repeat, GGGGCC, in a non-coding region of the gene and a massive expansion of this repeat causes ALS, FTD, or both (FTD/ALS). Many questions lie ahead. What does this gene normally do? What is the consequence of an enormous GGGGCC repeat expansion on that gene's function? Could that hexanucleotide repeat expansion have additional pathological actions unrelated to C9orf72 function? There has been tremendous progress on all fronts in the quest to define how C9orf72 mutations cause disease. Many new experimental models have been constructed and unleashed in powerful genetic screens. Studies in mouse and human patient samples, including iPS-derived neurons, have provided unprecedented insights into pathogenic mechanisms. Three major hypotheses have emerged and are still being hotly debated in the field. These include (1) loss of function owing to decrease in the abundance of C9orf72 protein and its ability to carryout its still unknown cellular role; (2) RNA toxicity from bidirectionally transcribed sense (GGGGCC) and antisense (GGCCCC) transcripts that accumulate in RNA foci and might sequester critical RNA-binding proteins; (3) proteotoxicity from dipeptide repeat proteins produced by an unconventional form of translation from the expanded nucleotide repeats. Here we review the evidence in favor and against each of these three hypotheses. We also suggest additional experiments and considerations that we propose will help clarify which mechanism(s) are most important for driving disease and therefore most critical for considering during the development of therapeutic interventions. This article is part of a Special Issue entitled SI:RNA Metabolism in Disease.
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Affiliation(s)
- Aaron D Gitler
- Department of Genetics, Stanford University School of Medicine, 300 Pasteur Drive, M322 Alway Building, Stanford, CA 94305, USA.
| | - Hitomi Tsuiji
- Department of Biomedical Science, Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabedori, Mizuhoku, Nagoya, Aichi 467-8603, Japan.
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50
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Rzuczek SG, Southern MR, Disney MD. Studying a Drug-like, RNA-Focused Small Molecule Library Identifies Compounds That Inhibit RNA Toxicity in Myotonic Dystrophy. ACS Chem Biol 2015; 10:2706-15. [PMID: 26414664 DOI: 10.1021/acschembio.5b00430] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
There are many RNA targets in the transcriptome to which small molecule chemical probes and lead therapeutics are desired. However, identifying compounds that bind and modulate RNA function in cellulo is difficult. Although rational design approaches have been developed, they are still in their infancies and leave many RNAs "undruggable". In an effort to develop a small molecule library that is biased for binding RNA, we computationally identified "drug-like" compounds from screening collections that have favorable properties for binding RNA and for suitability as lead drugs. As proof-of-concept, this collection was screened for binding to and modulating the cellular dysfunction of the expanded repeating RNA (r(CUG)(exp)) that causes myotonic dystrophy type 1. Hit compounds bind the target in cellulo, as determined by the target identification approach Competitive Chemical Cross-Linking and Isolation by Pull-down (C-ChemCLIP), and selectively improve several disease-associated defects. The best compounds identified from our 320-member library are more potent in cellulo than compounds identified by high-throughput screening (HTS) campaigns against this RNA. Furthermore, the compound collection has a higher hit rate (9% compared to 0.01-3%), and the bioactive compounds identified are not charged; thus, RNA can be "drugged" with compounds that have favorable pharmacological properties. Finally, this RNA-focused small molecule library may serve as a useful starting point to identify lead "drug-like" chemical probes that affect the biological (dys)function of other RNA targets by direct target engagement.
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Affiliation(s)
- Suzanne G. Rzuczek
- Department
of Chemistry and ‡Translational Research Institute, The Scripps Research Institute, Scripps Florida, 130 Scripps Way #3A1, Jupiter, Florida 33458, United States
| | - Mark R. Southern
- Department
of Chemistry and ‡Translational Research Institute, The Scripps Research Institute, Scripps Florida, 130 Scripps Way #3A1, Jupiter, Florida 33458, United States
| | - Matthew D. Disney
- Department
of Chemistry and ‡Translational Research Institute, The Scripps Research Institute, Scripps Florida, 130 Scripps Way #3A1, Jupiter, Florida 33458, United States
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