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Feng Z, Liang P, Li Q, Nie Y, Zhang Y. Association between NKX2-5 rs29784 and infantile hypertrophic pyloric stenosis in Chinese Han population. Int J Clin Exp Med 2015; 8:2905-2910. [PMID: 25932253 PMCID: PMC4402900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 01/28/2015] [Indexed: 06/04/2023]
Abstract
PURPOSE The aim of this study was to evaluate the association of three single nucleotide polymorphisms (SNPs, rs11712066 and rs573872 near MBNL1, rs29784 near NKX2-5) with infantile hypertrophic pyloric stenosis (IHPS) in Chinese Han population. METHODS A total of 47 family trios consisting of infants with IHPS and their healthy biological parents were recruited for this study. Genotypes were determined using direct sequencing. Transmission disequilibrium test (TDT) was performed for family-based association analysis. RESULTS Genotypic distributions of three SNPs in both groups (patients and proband's parents) were in conformity with Hardy-Weinberg equilibrium (P > 0.05). There were significant preferential transmission of A allele of rs29784 from the parents to affected offspring (TDT: x(2) = 5.444, P = 0.0196). However, other two polymorphism loci (rs11712066 and rs573872) were not significant susceptibility loci for IHPS in Chinese Han population. CONCLUSIONS We found that there was a significant association between rs29784 and IHPS.
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Affiliation(s)
- Zhiqiang Feng
- Department of Gastroenterology, Guangzhou First People’s Hospital, Guangzhou Medical University, Guangzhou Digestive Disease CenterGuangzhou, China
- Guangzhou Key Laboratory of Digestive Disease, Guangzhou First People’s Hospital, Guangzhou Medical UniversityGuangzhou, China
| | - Peizhi Liang
- Department of Gastroenterology, Guangzhou First People’s Hospital, Guangzhou Medical University, Guangzhou Digestive Disease CenterGuangzhou, China
- Guangzhou Key Laboratory of Digestive Disease, Guangzhou First People’s Hospital, Guangzhou Medical UniversityGuangzhou, China
| | - Qingning Li
- Department of Gastroenterology, Guangzhou First People’s Hospital, Guangzhou Medical University, Guangzhou Digestive Disease CenterGuangzhou, China
- Guangzhou Key Laboratory of Digestive Disease, Guangzhou First People’s Hospital, Guangzhou Medical UniversityGuangzhou, China
| | - Yuqiang Nie
- Department of Gastroenterology, Guangzhou First People’s Hospital, Guangzhou Medical University, Guangzhou Digestive Disease CenterGuangzhou, China
- Guangzhou Key Laboratory of Digestive Disease, Guangzhou First People’s Hospital, Guangzhou Medical UniversityGuangzhou, China
| | - Youxiang Zhang
- Department of Pediatrics, Guangzhou First People’s Hospital, Guangzhou Medical UniversityGuangzhou, China
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52
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Antonacci S, Forand D, Wolf M, Tyus C, Barney J, Kellogg L, Simon MA, Kerr G, Wells KL, Younes S, Mortimer NT, Olesnicky EC, Killian DJ. Conserved RNA-binding proteins required for dendrite morphogenesis in Caenorhabditis elegans sensory neurons. G3 (BETHESDA, MD.) 2015; 5:639-53. [PMID: 25673135 PMCID: PMC4390579 DOI: 10.1534/g3.115.017327] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 02/09/2015] [Indexed: 01/22/2023]
Abstract
The regulation of dendritic branching is critical for sensory reception, cell-cell communication within the nervous system, learning, memory, and behavior. Defects in dendrite morphology are associated with several neurologic disorders; thus, an understanding of the molecular mechanisms that govern dendrite morphogenesis is important. Recent investigations of dendrite morphogenesis have highlighted the importance of gene regulation at the posttranscriptional level. Because RNA-binding proteins mediate many posttranscriptional mechanisms, we decided to investigate the extent to which conserved RNA-binding proteins contribute to dendrite morphogenesis across phyla. Here we identify a core set of RNA-binding proteins that are important for dendrite morphogenesis in the PVD multidendritic sensory neuron in Caenorhabditis elegans. Homologs of each of these genes were previously identified as important in the Drosophila melanogaster dendritic arborization sensory neurons. Our results suggest that RNA processing, mRNA localization, mRNA stability, and translational control are all important mechanisms that contribute to dendrite morphogenesis, and we present a conserved set of RNA-binding proteins that regulate these processes in diverse animal species. Furthermore, homologs of these genes are expressed in the human brain, suggesting that these RNA-binding proteins are candidate regulators of dendrite development in humans.
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Affiliation(s)
- Simona Antonacci
- Department of Molecular Biology, Colorado College, Colorado Springs, Colorado 80903
| | - Daniel Forand
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, Colorado 80918
| | - Margaret Wolf
- Department of Molecular Biology, Colorado College, Colorado Springs, Colorado 80903
| | - Courtney Tyus
- Department of Molecular Biology, Colorado College, Colorado Springs, Colorado 80903
| | - Julia Barney
- Department of Molecular Biology, Colorado College, Colorado Springs, Colorado 80903
| | - Leah Kellogg
- Department of Molecular Biology, Colorado College, Colorado Springs, Colorado 80903
| | - Margo A Simon
- Department of Molecular Biology, Colorado College, Colorado Springs, Colorado 80903
| | - Genevieve Kerr
- Department of Molecular Biology, Colorado College, Colorado Springs, Colorado 80903
| | - Kristen L Wells
- Department of Molecular Biology, Colorado College, Colorado Springs, Colorado 80903
| | - Serena Younes
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, Colorado 80918
| | - Nathan T Mortimer
- Department of Biological Sciences, University of Denver, Denver, Colorado 80208
| | - Eugenia C Olesnicky
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, Colorado 80918
| | - Darrell J Killian
- Department of Molecular Biology, Colorado College, Colorado Springs, Colorado 80903
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53
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Chau A, Kalsotra A. Developmental insights into the pathology of and therapeutic strategies for DM1: Back to the basics. Dev Dyn 2015; 244:377-90. [PMID: 25504326 DOI: 10.1002/dvdy.24240] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 11/25/2014] [Accepted: 11/27/2014] [Indexed: 12/25/2022] Open
Abstract
Myotonic Dystrophy type 1 (DM1), the most prevalent adult onset muscular dystrophy, is a trinucleotide repeat expansion disease caused by CTG expansion in the 3'-UTR of DMPK gene. This expansion results in the expression of toxic gain-of-function RNA that forms ribonuclear foci and disrupts normal activities of RNA-binding proteins belonging to the MBNL and CELF families. Changes in alternative splicing, translation, localization, and mRNA stability due to sequestration of MBNL proteins and up-regulation of CELF1 are key to DM1 pathology. However, recent discoveries indicate that pathogenic mechanisms of DM1 involves many other factors as well, including repeat associated translation, activation of PKC-dependent signaling pathway, aberrant polyadenylation, and microRNA deregulation. Expression of the toxic repeat RNA culminates in the developmental remodeling of the transcriptome, which produces fetal isoforms of proteins that are unable to fulfill the physiological requirements of adult tissues. This review will describe advances in the understanding of DM1 pathogenesis as well as current therapeutic developments for DM1.
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Affiliation(s)
- Anthony Chau
- Department of Biochemistry, University of Illinois, Urbana-Champaign, Illinois; Department of Medical Biochemistry, University of Illinois, Urbana-Champaign, Illinois; Institute of Genomic Biology, University of Illinois, Urbana-Champaign, Illinois
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54
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Rigo F, Seth PP, Bennett CF. Antisense oligonucleotide-based therapies for diseases caused by pre-mRNA processing defects. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 825:303-52. [PMID: 25201110 DOI: 10.1007/978-1-4939-1221-6_9] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Before a messenger RNA (mRNA) is translated into a protein in the cytoplasm, its pre-mRNA precursor is extensively processed through capping, splicing and polyadenylation in the nucleus. Defects in the processing of pre-mRNAs due to mutations in RNA sequences often cause disease. Traditional small molecules or protein-based therapeutics are not well suited for correcting processing defects by targeting RNA. However, antisense oligonucleotides (ASOs) designed to bind RNA by Watson-Crick base pairing can target most RNA transcripts and have emerged as the ideal therapeutic agents for diseases that are caused by pre-mRNA processing defects. Here we review the diverse ASO-based mechanisms that can be exploited to modulate the expression of RNA. We also discuss how advancements in medicinal chemistry and a deeper understanding of the pharmacokinetic and toxicological properties of ASOs have enabled their use as therapeutic agents. We end by describing how ASOs have been used successfully to treat various pre-mRNA processing diseases in animal models.
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Affiliation(s)
- Frank Rigo
- Isis Pharmaceuticals, 2855 Gazelle Court, Carlsbad, CA, USA,
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55
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Kearse MG, Todd PK. Repeat-associated non-AUG translation and its impact in neurodegenerative disease. Neurotherapeutics 2014; 11:721-31. [PMID: 25005000 PMCID: PMC4391382 DOI: 10.1007/s13311-014-0292-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Nucleotide repeat expansions underlie numerous human neurological disorders. Repeats can trigger toxicity through multiple pathogenic mechanisms, including RNA gain-of-function, protein gain-of-function, and protein loss-of-function pathways. Traditionally, inference of the underlying pathogenic mechanism derives from the repeat location, with dominantly inherited repeats within transcribed noncoding sequences eliciting toxicity predominantly as RNA via sequestration of specific RNA binding proteins. However, recent findings question this assumption and suggest that repeats outside of annotated open reading frames may also trigger toxicity through a novel form of protein translational initiation known as repeat-associated non-AUG (RAN) translation. To date, RAN translation has been implicated in 4 nucleotide repeat expansion disorders: spinocerebellar ataxia type 8; myotonic dystrophy type 1 with CTG•CAG repeats; C9orf72 amyotrophic lateral sclerosis/frontotemporal dementia with GGGGCC•GGCCCC repeats; and fragile X-associated tremor/ataxia syndrome with CGG repeats. RAN translation contributes to hallmark pathological characteristics in these disorders by producing homopolymeric or dipeptide repeat proteins. Here, we review what is known about RAN translation, with an emphasis on how differences in both repeat sequence and context may confer different requirements for unconventional initiation. We then discuss how this new mechanism of translational initiation might function in normal physiology and lay out a roadmap for addressing the numerous questions that remain.
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Affiliation(s)
- Michael G. Kearse
- />Department of Neurology, University of Michigan Medical School, 4005 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200 USA
| | - Peter K. Todd
- />Department of Neurology, University of Michigan Medical School, 4005 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200 USA
- />Veterans Affairs Medical Center, Ann Arbor, MI 48105 USA
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RBFOX1 cooperates with MBNL1 to control splicing in muscle, including events altered in myotonic dystrophy type 1. PLoS One 2014; 9:e107324. [PMID: 25211016 PMCID: PMC4161394 DOI: 10.1371/journal.pone.0107324] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 08/12/2014] [Indexed: 12/22/2022] Open
Abstract
With the goal of identifying splicing alterations in myotonic dystrophy 1 (DM1) tissues that may yield insights into targets or mechanisms, we have surveyed mis-splicing events in three systems using a RT-PCR screening and validation platform. First, a transgenic mouse model expressing CUG-repeats identified splicing alterations shared with other mouse models of DM1. Second, using cell cultures from human embryonic muscle, we noted that DM1-associated splicing alterations were significantly enriched in cytoskeleton (e.g. SORBS1, TACC2, TTN, ACTN1 and DMD) and channel (e.g. KCND3 and TRPM4) genes. Third, of the splicing alterations occurring in adult DM1 tissues, one produced a dominant negative variant of the splicing regulator RBFOX1. Notably, half of the splicing events controlled by MBNL1 were co-regulated by RBFOX1, and several events in this category were mis-spliced in DM1 tissues. Our results suggest that reduced RBFOX1 activity in DM1 tissues may amplify several of the splicing alterations caused by the deficiency in MBNL1.
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57
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Konieczny P, Stepniak-Konieczna E, Sobczak K. MBNL proteins and their target RNAs, interaction and splicing regulation. Nucleic Acids Res 2014; 42:10873-87. [PMID: 25183524 PMCID: PMC4176163 DOI: 10.1093/nar/gku767] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Muscleblind-like (MBNL) proteins are key regulators of precursor and mature mRNA metabolism in mammals. Based on published and novel data, we explore models of tissue-specific MBNL interaction with RNA. We portray MBNL domains critical for RNA binding and splicing regulation, and the structure of MBNL's normal and pathogenic RNA targets, particularly in the context of myotonic dystrophy (DM), in which expanded CUG or CCUG repeat transcripts sequester several nuclear proteins including MBNLs. We also review the properties of MBNL/RNA complex, including recent data obtained from UV cross-linking and immunoprecipitation (CLIP-Seq), and discuss how this interaction shapes normal MBNL-dependent alternative splicing regulation. Finally, we review how this acquired knowledge about the pathogenic RNA structure and nature of MBNL sequestration can be translated into the design of therapeutic strategies against DM.
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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
| | - 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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58
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Garcia SMDA, Tabach Y, Lourenço GF, Armakola M, Ruvkun G. Identification of genes in toxicity pathways of trinucleotide-repeat RNA in C. elegans. Nat Struct Mol Biol 2014; 21:712-20. [PMID: 25038802 PMCID: PMC4125460 DOI: 10.1038/nsmb.2858] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 06/18/2014] [Indexed: 01/15/2023]
Abstract
Myotonic dystrophy disorders are caused by expanded CUG repeats in non-coding regions. To reveal mechanisms of CUG repeat pathogenesis we used C. elegans expressing CUG repeats to identify gene inactivations that modulate CUG repeat toxicity. We identified 15 conserved genes that function as suppressors or enhancers of CUG repeat-induced toxicity and modulate formation of nuclear RNA foci by CUG repeats. These genes regulated CUG repeat-induced toxicity through distinct mechanisms including RNA export and RNA clearance, suggesting that CUG repeat toxicity is mediated by multiple pathways. A subset is shared with other degenerative disorders. The nonsense-mediated mRNA decay (NMD) pathway plays a conserved role regulating CUG repeat RNA transcript levels and toxicity, and NMD recognition of toxic RNAs depends on 3′UTR GC nucleotide content. Our studies suggest a broader surveillance role for NMD where variations in this pathway influence multiple degenerative diseases.
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Affiliation(s)
- Susana M D A Garcia
- 1] Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, USA. [2] Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Yuval Tabach
- 1] Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, USA. [2] Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Guinevere F Lourenço
- 1] Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, USA. [2] Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA. [3]
| | - Maria Armakola
- 1] Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, USA. [2] Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Gary Ruvkun
- 1] Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, USA. [2] Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
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59
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Sareen D, O'Rourke JG, Meera P, Muhammad AKMG, Grant S, Simpkinson M, Bell S, Carmona S, Ornelas L, Sahabian A, Gendron T, Petrucelli L, Baughn M, Ravits J, Harms MB, Rigo F, Bennett CF, Otis TS, Svendsen CN, Baloh RH. Targeting RNA foci in iPSC-derived motor neurons from ALS patients with a C9ORF72 repeat expansion. Sci Transl Med 2014; 5:208ra149. [PMID: 24154603 DOI: 10.1126/scitranslmed.3007529] [Citation(s) in RCA: 514] [Impact Index Per Article: 51.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a severe neurodegenerative condition characterized by loss of motor neurons in the brain and spinal cord. Expansions of a hexanucleotide repeat (GGGGCC) in the noncoding region of the C9ORF72 gene are the most common cause of the familial form of ALS (C9-ALS), as well as frontotemporal lobar degeneration and other neurological diseases. How the repeat expansion causes disease remains unclear, with both loss of function (haploinsufficiency) and gain of function (either toxic RNA or protein products) proposed. We report a cellular model of C9-ALS with motor neurons differentiated from induced pluripotent stem cells (iPSCs) derived from ALS patients carrying the C9ORF72 repeat expansion. No significant loss of C9ORF72 expression was observed, and knockdown of the transcript was not toxic to cultured human motor neurons. Transcription of the repeat was increased, leading to accumulation of GGGGCC repeat-containing RNA foci selectively in C9-ALS iPSC-derived motor neurons. Repeat-containing RNA foci colocalized with hnRNPA1 and Pur-α, suggesting that they may be able to alter RNA metabolism. C9-ALS motor neurons showed altered expression of genes involved in membrane excitability including DPP6, and demonstrated a diminished capacity to fire continuous spikes upon depolarization compared to control motor neurons. Antisense oligonucleotides targeting the C9ORF72 transcript suppressed RNA foci formation and reversed gene expression alterations in C9-ALS motor neurons. These data show that patient-derived motor neurons can be used to delineate pathogenic events in ALS.
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Affiliation(s)
- Dhruv Sareen
- Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA
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60
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Meola G, Cardani R. Myotonic dystrophies: An update on clinical aspects, genetic, pathology, and molecular pathomechanisms. Biochim Biophys Acta Mol Basis Dis 2014; 1852:594-606. [PMID: 24882752 DOI: 10.1016/j.bbadis.2014.05.019] [Citation(s) in RCA: 213] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 05/19/2014] [Accepted: 05/20/2014] [Indexed: 01/18/2023]
Abstract
Myotonic dystrophy (DM) is the most common adult muscular dystrophy, characterized by autosomal dominant progressive myopathy, myotonia and multiorgan involvement. To date two distinct forms caused by similar mutations have been identified. Myotonic dystrophy type 1 (DM1, Steinert's disease) is caused by a (CTG)n expansion in DMPK, while myotonic dystrophy type 2 (DM2) is caused by a (CCTG)n expansion in ZNF9/CNBP. When transcribed into CUG/CCUG-containing RNA, mutant transcripts aggregate as nuclear foci that sequester RNA-binding proteins, resulting in spliceopathy of downstream effector genes. However, it is now clear that additional pathogenic mechanism like changes in gene expression, protein translation and micro-RNA metabolism may also contribute to disease pathology. Despite clinical and genetic similarities, DM1 and DM2 are distinct disorders requiring different diagnostic and management strategies. This review is an update on the recent advances in the understanding of the molecular mechanisms behind myotonic dystrophies. This article is part of a Special Issue entitled: Neuromuscular Diseases: Pathology and Molecular Pathogenesis.
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Affiliation(s)
- Giovanni Meola
- Department of Neurology, IRCCS Policlinico San Donato, University of Milan, San Donato Milanese, Milan, Italy; Laboratory of Muscle Histopathology and Molecular Biology, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy.
| | - Rosanna Cardani
- Laboratory of Muscle Histopathology and Molecular Biology, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy.
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61
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Santoro M, Piacentini R, Masciullo M, Bianchi MLE, Modoni A, Podda MV, Ricci E, Silvestri G, Grassi C. Alternative splicing alterations of Ca2+handling genes are associated with Ca2+signal dysregulation in myotonic dystrophy type 1 (DM1) and type 2 (DM2) myotubes. Neuropathol Appl Neurobiol 2014; 40:464-76. [DOI: 10.1111/nan.12076] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 07/24/2013] [Indexed: 11/29/2022]
Affiliation(s)
| | | | - Marcella Masciullo
- Department of Geriatrics, Neuroscience and Orthopedics; Center of Neuromuscular Disorders; Università Cattolica; Rome Italy
- IRCCS San Raffaele Pisana; Rome Italy
| | - Maria Laura Ester Bianchi
- Department of Geriatrics, Neuroscience and Orthopedics; Center of Neuromuscular Disorders; Università Cattolica; Rome Italy
| | - Anna Modoni
- Department of Geriatrics, Neuroscience and Orthopedics; Center of Neuromuscular Disorders; Università Cattolica; Rome Italy
| | | | - Enzo Ricci
- Department of Geriatrics, Neuroscience and Orthopedics; Center of Neuromuscular Disorders; Università Cattolica; Rome Italy
| | - Gabriella Silvestri
- Department of Geriatrics, Neuroscience and Orthopedics; Center of Neuromuscular Disorders; Università Cattolica; Rome Italy
| | - Claudio Grassi
- Institute of Human Physiology; Università Cattolica; Rome Italy
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62
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Genome wide identification of aberrant alternative splicing events in myotonic dystrophy type 2. PLoS One 2014; 9:e93983. [PMID: 24722564 PMCID: PMC3983107 DOI: 10.1371/journal.pone.0093983] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 03/10/2014] [Indexed: 02/01/2023] Open
Abstract
Myotonic dystrophy type 2 (DM2) is a genetic, autosomal dominant disease due to expansion of tetraplet (CCTG) repetitions in the first intron of the ZNF9/CNBP gene. DM2 is a multisystemic disorder affecting the skeletal muscle, the heart, the eye and the endocrine system. According to the proposed pathological mechanism, the expanded tetraplets have an RNA toxic effect, disrupting the splicing of many mRNAs. Thus, the identification of aberrantly spliced transcripts is instrumental for our understanding of the molecular mechanisms underpinning the disease. The aim of this study was the identification of new aberrant alternative splicing events in DM2 patients. By genome wide analysis of 10 DM2 patients and 10 controls (CTR), we identified 273 alternative spliced exons in 218 genes. While many aberrant splicing events were already identified in the past, most were new. A subset of these events was validated by qPCR assays in 19 DM2 and 15 CTR subjects. To gain insight into the molecular pathways involving the identified aberrantly spliced genes, we performed a bioinformatics analysis with Ingenuity system. This analysis indicated a deregulation of development, cell survival, metabolism, calcium signaling and contractility. In conclusion, our genome wide analysis provided a database of aberrant splicing events in the skeletal muscle of DM2 patients. The affected genes are involved in numerous pathways and networks important for muscle physio-pathology, suggesting that the identified variants may contribute to DM2 pathogenesis.
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63
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Bargiela A, Llamusi B, Cerro-Herreros E, Artero R. Two enhancers control transcription of Drosophila muscleblind in the embryonic somatic musculature and in the central nervous system. PLoS One 2014; 9:e93125. [PMID: 24667536 PMCID: PMC3965525 DOI: 10.1371/journal.pone.0093125] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 03/01/2014] [Indexed: 12/19/2022] Open
Abstract
The phylogenetically conserved family of Muscleblind proteins are RNA-binding factors involved in a variety of gene expression processes including alternative splicing regulation, RNA stability and subcellular localization, and miRNA biogenesis, which typically contribute to cell-type specific differentiation. In humans, sequestration of Muscleblind-like proteins MBNL1 and MBNL2 has been implicated in degenerative disorders, particularly expansion diseases such as myotonic dystrophy type 1 and 2. Drosophila muscleblind was previously shown to be expressed in embryonic somatic and visceral muscle subtypes, and in the central nervous system, and to depend on Mef2 for transcriptional activation. Genomic approaches have pointed out candidate gene promoters and tissue-specific enhancers, but experimental confirmation of their regulatory roles was lacking. In our study, luciferase reporter assays in S2 cells confirmed that regions P1 (515 bp) and P2 (573 bp), involving the beginning of exon 1 and exon 2, respectively, were able to initiate RNA transcription. Similarly, transgenic Drosophila embryos carrying enhancer reporter constructs supported the existence of two regulatory regions which control embryonic expression of muscleblind in the central nerve cord (NE, neural enhancer; 830 bp) and somatic (skeletal) musculature (ME, muscle enhancer; 3.3 kb). Both NE and ME were able to boost expression from the Hsp70 heterologous promoter. In S2 cell assays most of the ME enhancer activation could be further narrowed down to a 1200 bp subregion (ME.3), which contains predicted binding sites for the Mef2 transcription factor. The present study constitutes the first characterization of muscleblind enhancers and will contribute to a deeper understanding of the transcriptional regulation of the gene.
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Affiliation(s)
- Ariadna Bargiela
- Translational Genomics Group, Department of Genetics, University of Valencia, Valencia, Spain
- INCLIVA Health Research Institute, Valencia, Spain
| | - Beatriz Llamusi
- Translational Genomics Group, Department of Genetics, University of Valencia, Valencia, Spain
- INCLIVA Health Research Institute, Valencia, Spain
| | - Estefanía Cerro-Herreros
- Translational Genomics Group, Department of Genetics, University of Valencia, Valencia, Spain
- INCLIVA Health Research Institute, Valencia, Spain
| | - Ruben Artero
- Translational Genomics Group, Department of Genetics, University of Valencia, Valencia, Spain
- INCLIVA Health Research Institute, Valencia, Spain
- * E-mail:
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64
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Giudice J, Cooper TA. RNA-binding proteins in heart development. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 825:389-429. [PMID: 25201112 DOI: 10.1007/978-1-4939-1221-6_11] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
RNA-binding proteins (RBPs) are key players of posttranscriptional regulation occurring during normal tissue development. All tissues examined thus far have revealed the importance of RBPs in the regulation of complex networks involved in organ morphogenesis, maturation, and function. They are responsible for controlling tissue-specific gene expression by regulating alternative splicing, mRNA stability, translation, and poly-adenylation. The heart is the first organ form during embryonic development and is also the first to acquire functionality. Numerous remodeling processes take place during late cardiac development since fetal heart first adapts to birth and then undergoes a transition to adult functionality. This physiological remodeling involves transcriptional and posttranscriptional networks that are regulated by RBPs. Disruption of the normal regulatory networks has been shown to cause cardiomyopathy in humans and animal models. Here we review the complexity of late heart development and the current information regarding how RBPs control aspects of postnatal heart development. We also review how activities of RBPs are modulated adding complexity to the regulation of developmental networks.
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Affiliation(s)
- Jimena Giudice
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, 77030, USA,
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65
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Edge C, Gooding C, Smith CWJ. Dissecting domains necessary for activation and repression of splicing by Muscleblind-like protein 1. BMC Mol Biol 2013; 14:29. [PMID: 24373687 PMCID: PMC3880588 DOI: 10.1186/1471-2199-14-29] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 12/16/2013] [Indexed: 01/06/2023] Open
Abstract
Background Alternative splicing contributes to the diversity of the proteome, and provides the cell with an important additional layer of regulation of gene expression. Among the many RNA binding proteins that regulate alternative splicing pathways are the Muscleblind-like (MBNL) proteins. MBNL proteins bind YGCY motifs in RNA via four CCCH zinc fingers arranged in two tandem arrays, and play a crucial role in the transition from embryonic to adult muscle splicing patterns, deregulation of which leads to Myotonic Dystrophy. Like many other RNA binding proteins, MBNL proteins can act as both activators or repressors of different splicing events. Results We used targeted point mutations to interfere with the RNA binding of MBNL1 zinc fingers individually and in combination. The effects of the mutations were tested in assays for splicing repression and activation, including overexpression, complementation of siRNA-mediated knockdown, and artificial tethering using MS2 coat protein. Mutations were tested in the context of both full length MBNL1 as well as a series of truncation mutants. Individual mutations within full length MBNL1 had little effect, but mutations in ZF1 and 2 combined were more detrimental than those in ZF 3 and 4, upon splicing activation, repression and RNA binding. Activation and repression both required linker sequences between ZF2 and 3, but activation was more sensitive to loss of linker sequences. Conclusions Our results highlight the importance of RNA binding by MBNL ZF domains 1 and 2 for splicing regulatory activity, even when the protein is artificially recruited to its regulatory location on target RNAs. However, RNA binding is not sufficient for activity; additional regions between ZF 2 and 3 are also essential. Activation and repression show differential sensitivity to truncation of this linker region, suggesting interactions with different sets of cofactors for the two types of activity.
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Affiliation(s)
| | | | - Christopher W J Smith
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK.
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Bachinski LL, Baggerly KA, Neubauer VL, Nixon TJ, Raheem O, Sirito M, Unruh AK, Zhang J, Nagarajan L, Timchenko LT, Bassez G, Eymard B, Gamez J, Ashizawa T, Mendell JR, Udd B, Krahe R. Most expression and splicing changes in myotonic dystrophy type 1 and type 2 skeletal muscle are shared with other muscular dystrophies. Neuromuscul Disord 2013; 24:227-40. [PMID: 24332166 DOI: 10.1016/j.nmd.2013.11.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 10/30/2013] [Accepted: 11/07/2013] [Indexed: 12/20/2022]
Abstract
The prevailing pathomechanistic paradigm for myotonic dystrophy (DM) is that aberrant expression of embryonic/fetal mRNA/protein isoforms accounts for most aspects of the pleiotropic phenotype. To identify aberrant isoforms in skeletal muscle of DM1 and DM2 patients, we performed exon-array profiling and RT-PCR validation on the largest DM sample set to date, including Duchenne, Becker and tibial muscular dystrophy (NMD) patients as disease controls, and non-disease controls. Strikingly, most expression and splicing changes in DM patients were shared with NMD controls. Comparison between DM and NMD identified almost no significant differences. We conclude that DM1 and DM2 are essentially identical for dysregulation of gene expression, and DM expression changes represent a subset of broader spectrum dystrophic changes. We found no evidence for qualitative splicing differences between DM1 and DM2. While some DM-specific splicing differences exist, most of the DM splicing differences were also seen in NMD controls. SSBP3 exon 6 missplicing was observed in all diseased muscle and led to reduced protein. We conclude there is no widespread DM-specific spliceopathy in skeletal muscle and suggest that missplicing in DM (and NMD) may not be the driving mechanism for the muscle pathology, since the same pathways show expression changes unrelated to splicing.
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Affiliation(s)
- Linda L Bachinski
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Keith A Baggerly
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Valerie L Neubauer
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Tamara J Nixon
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Olayinka Raheem
- Department of Neurology, Tampere University Hospital and Medical School, Tampere, Finland
| | - Mario Sirito
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Anna K Unruh
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jiexin Zhang
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Lalitha Nagarajan
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Lubov T Timchenko
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Guillaume Bassez
- Neuromuscular Reference Center, Henri Mondor University Hospital, INSERM U955, East-Paris University, Créteil, France
| | - Bruno Eymard
- Reference Center for Neuromuscular Diseases, Institute of Myology, Pitié-Salpêtrière Hospital, Paris, France
| | - Josep Gamez
- Neuromuscular Disorders Clinic, Neurology Department, Hospital General Vall d'Hebron, Barcelona, Spain
| | - Tetsuo Ashizawa
- Department of Neurology, McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Jerry R Mendell
- Division of Child Neurology, Nationwide Childrens Hospital, Ohio State University College of Medicine, Columbus, OH, USA
| | - Bjarne Udd
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA; Folkhälsan Institute of Genetics and Department of Medical Genetics, University of Helsinki, Finland; Department of Neurology, Vasa Central Hospital, Finland
| | - Ralf Krahe
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX, USA; Graduate Programs in Human & Molecular Genetics, University of Texas at Houston Graduate School in Biomedical Sciences, Houston, TX, USA; Graduate Programs in Genes & Development, University of Texas at Houston Graduate School in Biomedical Sciences, Houston, TX, USA.
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Gadalla SM, Pfeiffer RM, Kristinsson SY, Björkholm M, Hilbert JE, Moxley RT, Landgren O, Greene MH. Quantifying cancer absolute risk and cancer mortality in the presence of competing events after a myotonic dystrophy diagnosis. PLoS One 2013; 8:e79851. [PMID: 24236163 PMCID: PMC3827449 DOI: 10.1371/journal.pone.0079851] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 09/25/2013] [Indexed: 12/02/2022] Open
Abstract
Recent studies show that patients with myotonic dystrophy (DM) have an increased risk of specific malignancies, but estimates of absolute cancer risk accounting for competing events are lacking. Using the Swedish Patient Registry, we identified 1,081 patients with an inpatient and/or outpatient diagnosis of DM between 1987 and 2007. Date and cause of death and date of cancer diagnosis were extracted from the Swedish Cause of Death and Cancer Registries. We calculated non-parametric estimates of absolute cancer risk and cancer mortality accounting for the high non-cancer competing mortality associated with DM. Absolute cancer risk after DM diagnosis was 1.6% (95% CI=0.4-4%), 5% (95% CI=3-9%) and 9% (95% CI=6-13%) at ages 40, 50 and 60 years, respectively. Females had a higher absolute risk of all cancers combined than males: 9% (95% CI=4-14), and 13% (95% CI=9-20) vs. 2% (95%CI= 0.7-6) and 4% (95%CI=2-8) by ages 50 and 60 years, respectively) and developed cancer at younger ages (median age =51 years, range=22-74 vs. 57, range=43-84, respectively, p=0.02). Cancer deaths accounted for 10% of all deaths, with an absolute cancer mortality risk of 2% (95%CI=1-4.5%), 4% (95%CI=2-6%), and 6% (95%CI=4-9%) by ages 50, 60, and 70 years, respectively. No gender difference in cancer-specific mortality was observed (p=0.6). In conclusion, cancer significantly contributes to morbidity and mortality in DM patients, even after accounting for high competing DM mortality from non-neoplastic causes. It is important to apply population-appropriate, validated cancer screening strategies in DM patients.
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Affiliation(s)
- Shahinaz M. Gadalla
- Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ruth M. Pfeiffer
- Biostatistics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Sigurdur Y. Kristinsson
- Department of Medicine, Division of Hematology, Karolinska University Hospital Solna and Karolinska Institutet, Stockholm, Sweden
- Faculty of Medicine, University of Iceland and Department of Hematology, Landspitali National University Hospital, Reykjavik, Iceland
| | - Magnus Björkholm
- Department of Medicine, Division of Hematology, Karolinska University Hospital Solna and Karolinska Institutet, Stockholm, Sweden
| | - James E. Hilbert
- Department of Neurology, Neuromuscular Disease Center, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Richard T. Moxley
- Department of Neurology, Neuromuscular Disease Center, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Ola Landgren
- Metabolism Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Mark H. Greene
- Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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Peric S, Stojanovic VR, Nikolic A, Kacar A, Basta I, Pavlovic S, Lavrnic D. Peripheral neuropathy in patients with myotonic dystrophy type 1. Neurol Res 2013; 35:331-5. [DOI: 10.1179/1743132812y.0000000144] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Affiliation(s)
- Stojan Peric
- Neurology ClinicClinical Center of Serbia, School of Medicine, University of Belgrade, Belgrade, Serbia
| | | | - Ana Nikolic
- Neurology ClinicClinical Center of Serbia, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Aleksandra Kacar
- Neurology ClinicClinical Center of Serbia, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Ivana Basta
- Neurology ClinicClinical Center of Serbia, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Sanja Pavlovic
- Neurology ClinicClinical Center of Serbia, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Dragana Lavrnic
- Neurology ClinicClinical Center of Serbia, School of Medicine, University of Belgrade, Belgrade, Serbia
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Vihola A, Sirito M, Bachinski LL, Raheem O, Screen M, Suominen T, Krahe R, Udd B. Altered expression and splicing of Ca(2+) metabolism genes in myotonic dystrophies DM1 and DM2. Neuropathol Appl Neurobiol 2013; 39:390-405. [PMID: 22758909 DOI: 10.1111/j.1365-2990.2012.01289.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
AIMS Myotonic dystrophy types 1 and 2 (DM1 and DM2) are multisystem disorders caused by similar repeat expansion mutations, with similar yet distinct clinical features. Aberrant splicing of multiple effector genes, as well as dysregulation of transcription and translation, has been suggested to underlie different aspects of the complex phenotypes in DM1 and DM2. Ca(2+) plays a central role in both muscle contraction and control of gene expression, and recent expression profiling studies have indicated major perturbations of the Ca(2+) signalling pathways in DM. Here we have further investigated the expression of genes and proteins involved in Ca(2+) metabolism in DM patients, including Ca(2+) channels and Ca(2+) binding proteins. METHODS We used patient muscle biopsies to analyse mRNA expression and splicing of genes by microarray expression profiling and RT-PCR. We studied protein expression by immunohistochemistry and immunoblotting. RESULTS Most of the genes studied showed mRNA up-regulation in expression profiling. When analysed by immunohistochemistry the Ca(2+) release channel ryanodine receptor was reduced in DM1 and DM2, as was calsequestrin 2, a sarcoplasmic reticulum lumen Ca(2+) storage protein. Abnormal splicing of ATP2A1 was more pronounced in DM2 than DM1. CONCLUSIONS We observed abnormal mRNA and protein expression in DM affecting several proteins involved in Ca(2+) metabolism, with some differences between DM1 and DM2. Our protein expression studies are suggestive of a post-transcriptional defect(s) in the myotonic dystrophies.
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Affiliation(s)
- A Vihola
- Folkhälsan Institute of Genetics and Department of Medical Genetics, Haartman Institute, University of Helsinki, Helsinki, Finland.
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Targeted degradation of sense and antisense C9orf72 RNA foci as therapy for ALS and frontotemporal degeneration. Proc Natl Acad Sci U S A 2013; 110:E4530-9. [PMID: 24170860 DOI: 10.1073/pnas.1318835110] [Citation(s) in RCA: 438] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Expanded hexanucleotide repeats in the chromosome 9 open reading frame 72 (C9orf72) gene are the most common genetic cause of ALS and frontotemporal degeneration (FTD). Here, we identify nuclear RNA foci containing the hexanucleotide expansion (GGGGCC) in patient cells, including white blood cells, fibroblasts, glia, and multiple neuronal cell types (spinal motor, cortical, hippocampal, and cerebellar neurons). RNA foci are not present in sporadic ALS, familial ALS/FTD caused by other mutations (SOD1, TDP-43, or tau), Parkinson disease, or nonneurological controls. Antisense oligonucleotides (ASOs) are identified that reduce GGGGCC-containing nuclear foci without altering overall C9orf72 RNA levels. By contrast, siRNAs fail to reduce nuclear RNA foci despite marked reduction in overall C9orf72 RNAs. Sustained ASO-mediated lowering of C9orf72 RNAs throughout the CNS of mice is demonstrated to be well tolerated, producing no behavioral or pathological features characteristic of ALS/FTD and only limited RNA expression alterations. Genome-wide RNA profiling identifies an RNA signature in fibroblasts from patients with C9orf72 expansion. ASOs targeting sense strand repeat-containing RNAs do not correct this signature, a failure that may be explained, at least in part, by discovery of abundant RNA foci with C9orf72 repeats transcribed in the antisense (GGCCCC) direction, which are not affected by sense strand-targeting ASOs. Taken together, these findings support a therapeutic approach by ASO administration to reduce hexanucleotide repeat-containing RNAs and raise the potential importance of targeting expanded RNAs transcribed in both directions.
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Donnelly CJ, Zhang PW, Pham JT, Heusler AR, Mistry NA, Vidensky S, Daley EL, Poth EM, Hoover B, Fines DM, Maragakis N, Tienari PJ, Petrucelli L, Traynor BJ, Wang J, Rigo F, Bennett CF, Blackshaw S, Sattler R, Rothstein JD. RNA toxicity from the ALS/FTD C9ORF72 expansion is mitigated by antisense intervention. Neuron 2013; 80:415-28. [PMID: 24139042 PMCID: PMC4098943 DOI: 10.1016/j.neuron.2013.10.015] [Citation(s) in RCA: 691] [Impact Index Per Article: 62.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/02/2013] [Indexed: 12/11/2022]
Abstract
A hexanucleotide GGGGCC repeat expansion in the noncoding region of the C9ORF72 gene is the most common genetic abnormality in familial and sporadic amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The function of the C9ORF72 protein is unknown, as is the mechanism by which the repeat expansion could cause disease. Induced pluripotent stem cell (iPSC)-differentiated neurons from C9ORF72 ALS patients revealed disease-specific (1) intranuclear GGGGCCexp RNA foci, (2) dysregulated gene expression, (3) sequestration of GGGGCCexp RNA binding protein ADARB2, and (4) susceptibility to excitotoxicity. These pathological and pathogenic characteristics were confirmed in ALS brain and were mitigated with antisense oligonucleotide (ASO) therapeutics to the C9ORF72 transcript or repeat expansion despite the presence of repeat-associated non-ATG translation (RAN) products. These data indicate a toxic RNA gain-of-function mechanism as a cause of C9ORF72 ALS and provide candidate antisense therapeutics and candidate human pharmacodynamic markers for therapy.
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Affiliation(s)
- Christopher J. Donnelly
- Department of Neurology, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
- Brain Science Institute, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
| | - Ping-Wu Zhang
- Department of Neurology, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
- Brain Science Institute, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
| | - Jacqueline T. Pham
- Department of Cellular and Molecular Medicine, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
| | - Aaron R. Heusler
- Department of Biochemistry and Molecular Biology, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
| | - Nipun A. Mistry
- Department of Neurology, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
- Brain Science Institute, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
| | - Svetlana Vidensky
- Department of Neurology, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
- Brain Science Institute, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
| | - Elizabeth L. Daley
- Department of Neurology, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
- Brain Science Institute, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
| | - Erin M. Poth
- Department of Neuroscience, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
| | - Benjamin Hoover
- Department of Neurology, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
- Brain Science Institute, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
| | - Daniel M. Fines
- Department of Neurology, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
- Brain Science Institute, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
| | - Nicholas Maragakis
- Department of Neurology, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
| | - Pentti J. Tienari
- Biomedicum, Research Programs Unit, Molecular Neurology, University of Helsinki; Helsinki University Central Hospital, Department of Neurology, Haartmaninkatu 8, FIN-00290 Helsinki, Finland
| | - Leonard Petrucelli
- Department of Molecular Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224, USA
| | - Bryan J. Traynor
- Department of Neurology, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
- Laboratory of Neurogenetics, National Institute on Aging, National Institute of Health, 35 Convent Drive, Room 1A-1000, Bethesda, MD 20892, USA
| | - Jiou Wang
- Department of Neuroscience, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
- Department of Biochemistry and Molecular Biology, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
| | - Frank Rigo
- Isis Pharmaceuticals, 2855 Gazelle Court, Carlsbad, CA 92010, USA
| | - C. Frank Bennett
- Isis Pharmaceuticals, 2855 Gazelle Court, Carlsbad, CA 92010, USA
| | - Seth Blackshaw
- Department of Neuroscience, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
| | - Rita Sattler
- Department of Neurology, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
- Brain Science Institute, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
| | - Jeffrey D. Rothstein
- Department of Neurology, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
- Department of Neuroscience, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
- Department of Cellular and Molecular Medicine, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
- Brain Science Institute, Johns Hopkins University, 855 N Wolfe Street, Rangos 2–270, Baltimore, MD 21205, USA
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Lee KY, Li M, Manchanda M, Batra R, Charizanis K, Mohan A, Warren SA, Chamberlain CM, Finn D, Hong H, Ashraf H, Kasahara H, Ranum LPW, Swanson MS. Compound loss of muscleblind-like function in myotonic dystrophy. EMBO Mol Med 2013; 5:1887-900. [PMID: 24293317 PMCID: PMC3914532 DOI: 10.1002/emmm.201303275] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 08/30/2013] [Accepted: 09/06/2013] [Indexed: 02/04/2023] Open
Abstract
Myotonic dystrophy (DM) is a multi-systemic disease that impacts cardiac and skeletal muscle as well as the central nervous system (CNS). DM is unusual because it is an RNA-mediated disorder due to the expression of toxic microsatellite expansion RNAs that alter the activities of RNA processing factors, including the muscleblind-like (MBNL) proteins. While these mutant RNAs inhibit MBNL1 splicing activity in heart and skeletal muscles, Mbnl1 knockout mice fail to recapitulate the full-range of DM symptoms in these tissues. Here, we generate mouse Mbnl compound knockouts to test the hypothesis that Mbnl2 functionally compensates for Mbnl1 loss. Although Mbnl1−/−; Mbnl2−/− double knockouts (DKOs) are embryonic lethal, Mbnl1−/−; Mbnl2+/− mice are viable but develop cardinal features of DM muscle disease including reduced lifespan, heart conduction block, severe myotonia and progressive skeletal muscle weakness. Mbnl2 protein levels are elevated in Mbnl1−/− knockouts where Mbnl2 targets Mbnl1-regulated exons. These findings support the hypothesis that compound loss of MBNL function is a critical event in DM pathogenesis and provide novel mouse models to investigate additional pathways disrupted in this RNA-mediated disease.
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Affiliation(s)
- Kuang-Yung Lee
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL, USA; Department of Neurology, Chang Gung Memorial Hospital, Keelung, Taiwan
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Todd PK, Ackall FY, Hur J, Sharma K, Paulson HL, Dowling JJ. Transcriptional changes and developmental abnormalities in a zebrafish model of myotonic dystrophy type 1. Dis Model Mech 2013; 7:143-55. [PMID: 24092878 PMCID: PMC3882056 DOI: 10.1242/dmm.012427] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Myotonic dystrophy type I (DM1) is a multi-system, autosomal dominant disorder caused by expansion of a CTG repeat sequence in the 3′UTR of the DMPK gene. The size of the repeat sequence correlates with age at onset and disease severity, with large repeats leading to congenital forms of DM1 associated with hypotonia and intellectual disability. In models of adult DM1, expanded CUG repeats lead to an RNA toxic gain of function, mediated at least in part by sequestering specific RNA splicing proteins, most notably muscleblind-related (MBNL) proteins. However, the impact of CUG RNA repeat expression on early developmental processes is not well understood. To better understand early developmental processes in DM1, we utilized the zebrafish, Danio rerio, as a model system. Direct injection of (CUG)91 repeat-containing mRNA into single-cell embryos induces toxicity in the nervous system and muscle during early development. These effects manifest as abnormal morphology, behavioral abnormalities and broad transcriptional changes, as shown by cDNA microarray analysis. Co-injection of zebrafish mbnl2 RNA suppresses (CUG)91 RNA toxicity and reverses the associated behavioral and transcriptional abnormalities. Taken together, these findings suggest that early expression of exogenously transcribed CUG repeat RNA can disrupt normal muscle and nervous system development and provides a new model for DM1 research that is amenable to small-molecule therapeutic development.
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Affiliation(s)
- Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
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MBNL142 and MBNL143 gene isoforms, overexpressed in DM1-patient muscle, encode for nuclear proteins interacting with Src family kinases. Cell Death Dis 2013; 4:e770. [PMID: 23949219 PMCID: PMC3763452 DOI: 10.1038/cddis.2013.291] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 05/19/2013] [Accepted: 05/23/2013] [Indexed: 12/20/2022]
Abstract
Myotonic dystrophy type-1 (DM1) is the most prevalent form of muscular dystrophy in adults. This disorder is an RNA-dominant disease, caused by expansion of a CTG repeat in the DMPK gene that leads to a misregulation in the alternative splicing of pre-mRNAs. The longer muscleblind-like-1 (MBNL1) transcripts containing exon 5 and the respective protein isoforms (MBNL142-43) were found to be overexpressed in DM1 muscle and localized exclusively in the nuclei. In vitro assays showed that MBNL142-43 bind the Src-homology 3 domain of Src family kinases (SFKs) via their proline-rich motifs, enhancing the SFK activity. Notably, this association was also confirmed in DM1 muscle and myotubes. The recovery, mediated by an siRNA target to Ex5-MBNL142-43, succeeded in reducing the nuclear localization of both Lyn and MBNL142-43 proteins and in decreasing the level of tyrosine phosphorylated proteins. Our results suggest an additional molecular mechanism in the DM1 pathogenesis, based on an altered phosphotyrosine signalling pathway.
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Gauthier M, Marteyn A, Denis JA, Cailleret M, Giraud-Triboult K, Aubert S, Lecuyer C, Marie J, Furling D, Vernet R, Yanguas C, Baldeschi C, Pietu G, Peschanski M, Martinat C. A defective Krab-domain zinc-finger transcription factor contributes to altered myogenesis in myotonic dystrophy type 1. Hum Mol Genet 2013; 22:5188-98. [PMID: 23922231 DOI: 10.1093/hmg/ddt373] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Myotonic dystrophy type 1 (DM1) is an RNA-mediated disorder caused by a non-coding CTG repeat expansion that, in particular, provokes functional alteration of CUG-binding proteins. As a consequence, several genes with misregulated alternative splicing have been linked to clinical symptoms. In our search for additional molecular mechanisms that would trigger functional defects in DM1, we took advantage of mutant gene-carrying human embryonic stem cell lines to identify differentially expressed genes. Among the different genes found to be misregulated by DM1 mutation, one strongly downregulated gene encodes a transcription factor, ZNF37A. In this paper, we show that this defect in expression, which derives from a loss of RNA stability, is controlled by the RNA-binding protein, CUGBP1, and is associated with impaired myogenesis-a functional defect reminiscent of that observed in DM1. Loss of the ZNF37A protein results in changes in the expression of the subunit α1 of the receptor for the interleukin 13. This suggests that the pathological molecular mechanisms linking ZNF37A and myogenesis may involve the signaling pathway that is known to promote myoblast recruitment during development and regeneration.
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Stojanovic VR, Peric S, Paunic T, Pavlovic S, Cvitan E, Basta I, Peric M, Milicev M, Lavrnic D. Cardiologic predictors of sudden death in patients with myotonic dystrophy type 1. J Clin Neurosci 2013; 20:1002-6. [DOI: 10.1016/j.jocn.2012.09.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2012] [Revised: 09/19/2012] [Accepted: 09/29/2012] [Indexed: 11/16/2022]
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Molecular mechanisms of muscle atrophy in myotonic dystrophies. Int J Biochem Cell Biol 2013; 45:2280-7. [PMID: 23796888 DOI: 10.1016/j.biocel.2013.06.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 06/11/2013] [Accepted: 06/12/2013] [Indexed: 02/01/2023]
Abstract
Myotonic dystrophy type 1 (DM1) and myotonic dystrophy type 2 (DM2) are multisystemic diseases that primarily affect skeletal muscle, causing myotonia, muscle atrophy, and muscle weakness. DM1 and DM2 pathologies are caused by expansion of CTG and CCTG repeats in non-coding regions of the genes encoding myotonic dystrophy protein kinase (DMPK) and zinc finger protein 9 (ZNF9) respectively. These expansions cause DM pathologies through accumulation of mutant RNAs that alter RNA metabolism in patients' tissues by targeting RNA-binding proteins such as CUG-binding protein 1 (CUGBP1) and Muscle blind-like protein 1 (MBNL1). Despite overwhelming evidence showing the critical role of RNA-binding proteins in DM1 and DM2 pathologies, the downstream pathways by which these RNA-binding proteins cause muscle wasting and muscle weakness are not well understood. This review discusses the molecular pathways by which DM1 and DM2 mutations might cause muscle atrophy and describes progress toward the development of therapeutic interventions for muscle wasting and weakness in DM1 and DM2. This article is part of a Directed Issue entitled: Molecular basis of muscle wasting.
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78
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Poulos MG, Batra R, Li M, Yuan Y, Zhang C, Darnell RB, Swanson MS. Progressive impairment of muscle regeneration in muscleblind-like 3 isoform knockout mice. Hum Mol Genet 2013; 22:3547-58. [PMID: 23660517 DOI: 10.1093/hmg/ddt209] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The muscleblind-like (MBNL) genes encode alternative splicing factors that are essential for the postnatal development of multiple tissues, and the inhibition of MBNL activity by toxic C(C)UG repeat RNAs is a major pathogenic feature of the neuromuscular disease myotonic dystrophy. While MBNL1 controls fetal-to-adult splicing transitions in muscle and MBNL2 serves a similar role in the brain, the function of MBNL3 in vivo is unknown. Here, we report that mouse Mbnl3, which encodes protein isoforms that differ in the number of tandem zinc-finger RNA-binding motifs and subcellular localization, is expressed primarily during embryonic development but also transiently during injury-induced adult skeletal muscle regeneration. Mbnl3 expression is required for normal C2C12 myogenic differentiation and high-throughput sequencing combined with cross-linking/immunoprecipitation analysis indicates that Mbnl3 binds preferentially to the 3' untranslated regions of genes implicated in cell growth and proliferation. In addition, Mbnl3ΔE2 isoform knockout mice, which fail to express the major Mbnl3 nuclear isoform, show age-dependent delays in injury-induced muscle regeneration and impaired muscle function. These results suggest that Mbnl3 inhibition by toxic RNA expression may be a contributing factor to the progressive skeletal muscle weakness and wasting characteristic of myotonic dystrophy.
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Affiliation(s)
- Michael G Poulos
- Department of Molecular Genetics and Microbiology, Genetics Institute and the Center for NeuroGenetics, University of Florida, College of Medicine, Gainesville, FL 32610, USA
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79
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de Haro M, Al-Ramahi I, Jones KR, Holth JK, Timchenko LT, Botas J. Smaug/SAMD4A restores translational activity of CUGBP1 and suppresses CUG-induced myopathy. PLoS Genet 2013; 9:e1003445. [PMID: 23637619 PMCID: PMC3630084 DOI: 10.1371/journal.pgen.1003445] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 02/27/2013] [Indexed: 11/18/2022] Open
Abstract
We report the identification and characterization of a previously unknown suppressor of myopathy caused by expansion of CUG repeats, the mutation that triggers Myotonic Dystrophy Type 1 (DM1). We screened a collection of genes encoding RNA-binding proteins as candidates to modify DM1 pathogenesis using a well established Drosophila model of the disease. The screen revealed smaug as a powerful modulator of CUG-induced toxicity. Increasing smaug levels prevents muscle wasting and restores muscle function, while reducing its function exacerbates CUG-induced phenotypes. Using human myoblasts, we show physical interactions between human Smaug (SMAUG1/SMAD4A) and CUGBP1. Increased levels of SMAUG1 correct the abnormally high nuclear accumulation of CUGBP1 in myoblasts from DM1 patients. In addition, augmenting SMAUG1 levels leads to a reduction of inactive CUGBP1-eIF2α translational complexes and to a correction of translation of MRG15, a downstream target of CUGBP1. Therefore, Smaug suppresses CUG-mediated muscle wasting at least in part via restoration of translational activity of CUGBP1.
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Affiliation(s)
- Maria de Haro
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas, United States of America
| | - Ismael Al-Ramahi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas, United States of America
| | - Karlie R. Jones
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Jerrah K. Holth
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Lubov T. Timchenko
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Juan Botas
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas, United States of America
- * E-mail:
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80
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Sicot G, Gomes-Pereira M. RNA toxicity in human disease and animal models: from the uncovering of a new mechanism to the development of promising therapies. Biochim Biophys Acta Mol Basis Dis 2013; 1832:1390-409. [PMID: 23500957 DOI: 10.1016/j.bbadis.2013.03.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 03/01/2013] [Accepted: 03/04/2013] [Indexed: 01/06/2023]
Abstract
Mutant ribonucleic acid (RNA) molecules can be toxic to the cell, causing human disease through trans-acting dominant mechanisms. RNA toxicity was first described in myotonic dystrophy type 1, a multisystemic disorder caused by the abnormal expansion of a non-coding trinucleotide repeat sequence. The development of multiple and complementary animal models of disease has greatly contributed to clarifying the complex disease pathways mediated by toxic RNA molecules. RNA toxicity is not limited to myotonic dystrophy and spreads to an increasing number of human conditions, which share some unifying pathogenic events mediated by toxic RNA accumulation and disruption of RNA-binding proteins. The remarkable progress in the dissection of disease pathobiology resulted in the rational design of molecular therapies, which have been successfully tested in animal models. Toxic RNA diseases, and in particular myotonic dystrophy, clearly illustrate the critical contribution of animal models of disease in translational research: from gene mutation to disease mechanisms, and ultimately to therapy development. This article is part of a Special Issue entitled: Animal Models of Disease.
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81
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Mohamed S, Pruna L, Kaminsky P. [Increasing risk of tumors in myotonic dystrophy type 1]. Presse Med 2013; 42:e281-4. [PMID: 23477718 DOI: 10.1016/j.lpm.2013.01.052] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 01/02/2013] [Accepted: 01/16/2013] [Indexed: 10/27/2022] Open
Abstract
OBJECTIVE Myotonic dystrophy type 1 (DM1) is characterized by an unstable expansion of a CTG repeat resulting in altered mRNA biogenesis. Benign or malignant tumours are increasingly reported. The aim of the study was to evaluate the risk of tumor in a cohort of patients DM1. METHOD We retrospectively reviewed the medical records of every DM1 patient admitted in our neuromuscular center. Diagnoses of cancer and age at diagnosis were noted. The relative risk of a selected cancer was calculated using the data of the cancer registry obtained from the French "Institut de Veille Sanitaire". RESULTS A total of 109 French DM1 patients, aged 44.1±13.0 years, were studied, and 14 malignant tumours were observed, with a significant relative risk (RR) of thymoma, of gynaecologic cancers, of lung cancers. CONCLUSION While this cohort is small, our findings nevertheless suggest an increased risk of particular cancers in DM1. The toxic effects of mutant RNA may possibly affect oncogene expression or growth factor signalling pathways in cells. Clinical practice should include cancer screening and prevention of risk factors in DM1 patients.
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Affiliation(s)
- Shirine Mohamed
- Hôpitaux de Brabois, centre de référence des maladies neuromusculaires, centre hospitalier universitaire de Nancy, service de médecine interne orientée vers les maladies orphelines et systémiques, pôle des spécialités médicale, bâtiment Philippe-Canton, rue du Morvan, 54500 Vandoeuvre, France
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82
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Crum-Bailey JM, Dennison DH, Weiner WJ, Hawley JS. The neurology and corresponding genetics of fragile X disorders: insights into the genetics of neurodegeneration. FUTURE NEUROLOGY 2013. [DOI: 10.2217/fnl.12.92] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
There have been significant advances in understanding how the fragile X gene (FMR1) can lead to distinct neurological syndromes. Clinical features of two disorders – fragile X syndrome and fragile X-associated tremor ataxia syndrome (FXTAS) – are highlighted in this article. These two disorders – one a neurodevelopmental disorder, the other a neurodegenerative disorder – are caused by a single expanded CGG repeat sequence within the FMR1 gene. Minor differences in repeat length result in the markedly different phenotypes. Understanding the action of FMR1 in FXTAS and fragile X syndrome has yielded significant insights into the genetics of neurodegeneration. Moreover, the genetic model in FXTAS is similar to several other neurologic genetic disorders, suggesting there are common pathways shared by many phenotypically diverse progressive neurodegenerative disorders. Finally, it is possible that targeted therapies for disorders such as FXTAS may also be effective in other neurodegenerative disorders that share similar mechanisms of pathogenesis.
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Affiliation(s)
- Jennifer M Crum-Bailey
- Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Department of Neurology, Bethesda, MD 20889, USA
| | - David H Dennison
- Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Department of Neurology, Bethesda, MD 20889, USA
| | - William J Weiner
- University of Maryland School of Medicine, Department of Neurology, 110 S Paca Street 3-S-124, Baltimore MD 21201, USA
| | - Jason S Hawley
- Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Department of Neurology, Bethesda, MD 20889, USA.
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83
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Hernández-Hernández O, Guiraud-Dogan C, Sicot G, Huguet A, Luilier S, Steidl E, Saenger S, Marciniak E, Obriot H, Chevarin C, Nicole A, Revillod L, Charizanis K, Lee KY, Suzuki Y, Kimura T, Matsuura T, Cisneros B, Swanson MS, Trovero F, Buisson B, Bizot JC, Hamon M, Humez S, Bassez G, Metzger F, Buée L, Munnich A, Sergeant N, Gourdon G, Gomes-Pereira M. Myotonic dystrophy CTG expansion affects synaptic vesicle proteins, neurotransmission and mouse behaviour. Brain 2013; 136:957-70. [PMID: 23404338 DOI: 10.1093/brain/aws367] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Myotonic dystrophy type 1 is a complex multisystemic inherited disorder, which displays multiple debilitating neurological manifestations. Despite recent progress in the understanding of the molecular pathogenesis of myotonic dystrophy type 1 in skeletal muscle and heart, the pathways affected in the central nervous system are largely unknown. To address this question, we studied the only transgenic mouse line expressing CTG trinucleotide repeats in the central nervous system. These mice recreate molecular features of RNA toxicity, such as RNA foci accumulation and missplicing. They exhibit relevant behavioural and cognitive phenotypes, deficits in short-term synaptic plasticity, as well as changes in neurochemical levels. In the search for disease intermediates affected by disease mutation, a global proteomics approach revealed RAB3A upregulation and synapsin I hyperphosphorylation in the central nervous system of transgenic mice, transfected cells and post-mortem brains of patients with myotonic dystrophy type 1. These protein defects were associated with electrophysiological and behavioural deficits in mice and altered spontaneous neurosecretion in cell culture. Taking advantage of a relevant transgenic mouse of a complex human disease, we found a novel connection between physiological phenotypes and synaptic protein dysregulation, indicative of synaptic dysfunction in myotonic dystrophy type 1 brain pathology.
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Affiliation(s)
- Oscar Hernández-Hernández
- Inserm U781, Université Paris Descartes Sorbonne Paris Cité, Institut Imagine, Hôpital Necker-Enfants Malades, 75015 Paris, France.
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84
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Vlasova-St Louis I, Dickson AM, Bohjanen PR, Wilusz CJ. CELFish ways to modulate mRNA decay. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1829:695-707. [PMID: 23328451 DOI: 10.1016/j.bbagrm.2013.01.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 01/03/2013] [Accepted: 01/05/2013] [Indexed: 12/14/2022]
Abstract
The CELF family of RNA-binding proteins regulates many steps of mRNA metabolism. Although their best characterized function is in pre-mRNA splice site choice, CELF family members are also powerful modulators of mRNA decay. In this review we focus on the different modes of regulation that CELF proteins employ to mediate mRNA decay by binding to GU-rich elements. After starting with an overview of the importance of CELF proteins during development and disease pathogenesis, we then review the mRNA networks and cellular pathways these proteins regulate and the mechanisms by which they influence mRNA decay. Finally, we discuss how CELF protein activity is modulated during development and in response to cellular signals. We conclude by highlighting the priorities for new experiments in this field. This article is part of a Special Issue entitled: RNA Decay mechanisms.
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85
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Leger AJ, Mosquea LM, Clayton NP, Wu IH, Weeden T, Nelson CA, Phillips L, Roberts E, Piepenhagen PA, Cheng SH, Wentworth BM. Systemic delivery of a Peptide-linked morpholino oligonucleotide neutralizes mutant RNA toxicity in a mouse model of myotonic dystrophy. Nucleic Acid Ther 2013; 23:109-17. [PMID: 23308382 DOI: 10.1089/nat.2012.0404] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Expansions of CUG trinucleotide sequences in RNA transcripts provide the basis for toxic RNA gain-of-function that leads to detrimental changes in RNA metabolism. A CTG repeat element normally resides in the 3' untranslated region of the dystrophia myotonica-protein kinase (DMPK) gene, but when expanded it is the genetic lesion of myotonic dystrophy type 1 (DM1), a hereditary neuromuscular disease. The pathogenic DMPK transcript containing the CUG expansion is retained in ribonuclear foci as part of a complex with RNA-binding proteins such as muscleblind-like 1 (MBNL1), resulting in aberrant splicing of numerous RNA transcripts and consequent physiological abnormalities including myotonia. Herein, we demonstrate molecular and physiological amelioration of the toxic effects of mutant RNA in the HSA(LR) mouse model of DM1 by systemic administration of peptide-linked morpholino (PPMO) antisense oligonucleotides bearing a CAG repeat sequence. Intravenous administration of PPMO conjugates to HSA(LR) mice led to redistribution of Mbnl1 protein in myonuclei and corrections in abnormal RNA splicing. Additionally, myotonia was completely eliminated in PPMO-treated HSA(LR) mice. These studies provide proof of concept that neutralization of RNA toxicity by systemic delivery of antisense oligonucleotides that target the CUG repeat is an effective therapeutic approach for treating the skeletal muscle aspects of DM1 pathology.
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86
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Sobczak K, Wheeler TM, Wang W, Thornton CA. RNA interference targeting CUG repeats in a mouse model of myotonic dystrophy. Mol Ther 2012. [PMID: 23183533 DOI: 10.1038/mt.2012.222] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Myotonic dystrophy type 1 (DM1) is an RNA dominant disease caused by expression of DM protein kinase (DMPK) transcripts that contain an expanded CUG repeat (CUG(exp)). The toxic mRNA localizes to nuclear foci and sequesters proteins involved in the regulation of alternative splicing, such as, muscleblind-like 1 (MBNL1). Here, we used synthetic short interfering RNAs (siRNAs) to target CUG repeats and test the concept that inhibiting the expression of CUG(exp) RNA can mitigate features of DM1 in transgenic mice. Intramuscular injection and electroporation of siRNA resulted in ~70-80% downregulation of CUG(exp) transcripts. A limited survey of endogenous mouse transcripts that contain nonexpanded CUG or CAG repeats showed that most were not affected, though Txlnb containing (CUG)(9) was significantly reduced. By this strategy, the number and intensity of CUG(exp) nuclear foci were reduced and splicing of MBNL1-dependent exons was improved. These data suggest that the expanded CUG repeats are a potential target for allele-selective RNA interference.
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Affiliation(s)
- Krzysztof Sobczak
- Department of Neurology, University of Rochester Medical Center, Rochester, New York 14642, USA.
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87
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Llamusi B, Bargiela A, Fernandez-Costa JM, Garcia-Lopez A, Klima R, Feiguin F, Artero R. Muscleblind, BSF and TBPH are mislocalized in the muscle sarcomere of a Drosophila myotonic dystrophy model. Dis Model Mech 2012; 6:184-96. [PMID: 23118342 PMCID: PMC3529350 DOI: 10.1242/dmm.009563] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Myotonic dystrophy type 1 (DM1) is a genetic disease caused by the pathological expansion of a CTG trinucleotide repeat in the 3′ UTR of the DMPK gene. In the DMPK transcripts, the CUG expansions sequester RNA-binding proteins into nuclear foci, including transcription factors and alternative splicing regulators such as MBNL1. MBNL1 sequestration has been associated with key features of DM1. However, the basis behind a number of molecular and histological alterations in DM1 remain unclear. To help identify new pathogenic components of the disease, we carried out a genetic screen using a Drosophila model of DM1 that expresses 480 interrupted CTG repeats, i(CTG)480, and a collection of 1215 transgenic RNA interference (RNAi) fly lines. Of the 34 modifiers identified, two RNA-binding proteins, TBPH (homolog of human TAR DNA-binding protein 43 or TDP-43) and BSF (Bicoid stability factor; homolog of human LRPPRC), were of particular interest. These factors modified i(CTG)480 phenotypes in the fly eye and wing, and TBPH silencing also suppressed CTG-induced defects in the flight muscles. In Drosophila flight muscle, TBPH, BSF and the fly ortholog of MBNL1, Muscleblind (Mbl), were detected in sarcomeric bands. Expression of i(CTG)480 resulted in changes in the sarcomeric patterns of these proteins, which could be restored by coexpression with human MBNL1. Epistasis studies showed that Mbl silencing was sufficient to induce a subcellular redistribution of TBPH and BSF proteins in the muscle, which mimicked the effect of i(CTG)480 expression. These results provide the first description of TBPH and BSF as targets of Mbl-mediated CTG toxicity, and they suggest an important role of these proteins in DM1 muscle pathology.
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Affiliation(s)
- Beatriz Llamusi
- Translational Genomics Group, Department of Genetics, University of Valencia, Doctor Moliner 50, 46100 Burjasot, Valencia, Spain
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88
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Wang ET, Cody NAL, Jog S, Biancolella M, Wang TT, Treacy DJ, Luo S, Schroth GP, Housman DE, Reddy S, Lécuyer E, Burge CB. Transcriptome-wide regulation of pre-mRNA splicing and mRNA localization by muscleblind proteins. Cell 2012; 150:710-24. [PMID: 22901804 DOI: 10.1016/j.cell.2012.06.041] [Citation(s) in RCA: 365] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Revised: 04/30/2012] [Accepted: 06/20/2012] [Indexed: 11/17/2022]
Abstract
The muscleblind-like (Mbnl) family of RNA-binding proteins plays important roles in muscle and eye development and in myotonic dystrophy (DM), in which expanded CUG or CCUG repeats functionally deplete Mbnl proteins. We identified transcriptome-wide functional and biophysical targets of Mbnl proteins in brain, heart, muscle, and myoblasts by using RNA-seq and CLIP-seq approaches. This analysis identified several hundred splicing events whose regulation depended on Mbnl function in a pattern indicating functional interchangeability between Mbnl1 and Mbnl2. A nucleotide resolution RNA map associated repression or activation of exon splicing with Mbnl binding near either 3' splice site or near the downstream 5' splice site, respectively. Transcriptomic analysis of subcellular compartments uncovered a global role for Mbnls in regulating localization of mRNAs in both mouse and Drosophila cells, and Mbnl-dependent translation and protein secretion were observed for a subset of mRNAs with Mbnl-dependent localization. These findings hold several new implications for DM pathogenesis.
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Affiliation(s)
- Eric T Wang
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
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89
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Charizanis K, Lee KY, Batra R, Goodwin M, Zhang C, Yuan Y, Shiue L, Cline M, Scotti MM, Xia G, Kumar A, Ashizawa T, Clark HB, Kimura T, Takahashi MP, Fujimura H, Jinnai K, Yoshikawa H, Gomes-Pereira M, Gourdon G, Sakai N, Nishino S, Foster TC, Ares M, Darnell RB, Swanson MS. Muscleblind-like 2-mediated alternative splicing in the developing brain and dysregulation in myotonic dystrophy. Neuron 2012; 75:437-50. [PMID: 22884328 DOI: 10.1016/j.neuron.2012.05.029] [Citation(s) in RCA: 247] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2012] [Indexed: 02/06/2023]
Abstract
The RNA-mediated disease model for myotonic dystrophy (DM) proposes that microsatellite C(C)TG expansions express toxic RNAs that disrupt splicing regulation by altering MBNL1 and CELF1 activities. While this model explains DM manifestations in muscle, less is known about the effects of C(C)UG expression on the brain. Here, we report that Mbnl2 knockout mice develop several DM-associated central nervous system (CNS) features including abnormal REM sleep propensity and deficits in spatial memory. Mbnl2 is prominently expressed in the hippocampus and Mbnl2 knockouts show a decrease in NMDA receptor (NMDAR) synaptic transmission and impaired hippocampal synaptic plasticity. While Mbnl2 loss did not significantly alter target transcript levels in the hippocampus, misregulated splicing of hundreds of exons was detected using splicing microarrays, RNA-seq, and HITS-CLIP. Importantly, the majority of the Mbnl2-regulated exons examined were similarly misregulated in DM. We propose that major pathological features of the DM brain result from disruption of the MBNL2-mediated developmental splicing program.
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Affiliation(s)
- Konstantinos Charizanis
- Department of Molecular Genetics and Microbiology and the Center for NeuroGenetics, University of Florida, College of Medicine, Gainesville, FL 32610, USA
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90
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Udd B, Krahe R. The myotonic dystrophies: molecular, clinical, and therapeutic challenges. Lancet Neurol 2012; 11:891-905. [DOI: 10.1016/s1474-4422(12)70204-1] [Citation(s) in RCA: 335] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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91
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Wheeler TM, Leger AJ, Pandey SK, MacLeod AR, Nakamori M, Cheng SH, Wentworth BM, Bennett CF, Thornton CA. Targeting nuclear RNA for in vivo correction of myotonic dystrophy. Nature 2012; 488:111-5. [PMID: 22859208 PMCID: PMC4221572 DOI: 10.1038/nature11362] [Citation(s) in RCA: 367] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Accepted: 06/29/2012] [Indexed: 02/07/2023]
Abstract
Antisense oligonucleotides (ASOs) hold promise for gene-specific knockdown in diseases that involve RNA or protein gain-of-function. In the hereditary degenerative disease myotonic dystrophy type 1 (DM1), transcripts from the mutant allele contain an expanded CUG repeat1–3 and are retained in the nucleus4, 5. The mutant RNA exerts a toxic gain-of-function6, making it an appropriate target for therapeutic ASOs. However, despite improvements in ASO chemistry and design, systemic use of ASOs is limited because uptake in many tissues, including skeletal and cardiac muscle, is not sufficient to silence target mRNAs7, 8. Here we show that nuclear-retained transcripts containing expanded CUG (CUGexp) repeats are extraordinarily sensitive to antisense silencing. In a transgenic mouse model of DM1, systemic administration of ASOs caused a rapid knockdown of CUGexp RNA in skeletal muscle, correcting the physiological, histopathologic, and transcriptomic features of the disease. The effect was sustained for up to one year after treatment was discontinued. Systemically administered ASOs were also effective for muscle knockdown of Malat-1, a long noncoding RNA (lncRNA) that is retained in the nucleus9. These results provide a general strategy to correct RNA gain-of-function and modulate the expression of expanded repeats, lncRNAs, and other transcripts with prolonged nuclear residence.
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Affiliation(s)
- Thurman M Wheeler
- Department of Neurology, University of Rochester, 601 Elmwood Avenue, Rochester, New York 14642, USA
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92
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Combinatorial mutagenesis of MBNL1 zinc fingers elucidates distinct classes of regulatory events. Mol Cell Biol 2012; 32:4155-67. [PMID: 22890842 DOI: 10.1128/mcb.00274-12] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The RNA binding protein and alternative splicing factor Muscleblind-like 1 (MBNL1) has been a topic of intense study due to its role in myotonic dystrophy (DM) pathogenesis. MBNL1 contains four zinc finger (ZF) RNA binding domains arranged in two pairs. Through combinatorial mutagenesis of the ZF domains, we demonstrate that the pairs of ZFs have differential affinity for RNA and subsequently differential splicing activities. We evaluated splicing and binding activity for six MBNL1-mediated splicing events and found that the splicing activity profiles for the ZF mutants vary among transcripts. Clustering analysis of splicing profiles revealed that two distinct classes of MBNL1 pre-mRNA substrates exist. For some of the RNA transcripts tested, binding and splicing activity of the ZF mutants correlated. However, for some transcripts it appears that MBNL1 exerts robust splicing activity in the absence of RNA binding. We demonstrate that functionally distinct classes of MBNL1-mediated splicing events exist as defined by requirements for ZF-RNA interactions.
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93
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Lukáš Z, Falk M, Feit J, Souček O, Falková I, Štefančíková L, Janoušová E, Fajkusová L, Zaorálková J, Hrabálková R. Sequestration of MBNL1 in tissues of patients with myotonic dystrophy type 2. Neuromuscul Disord 2012; 22:604-16. [DOI: 10.1016/j.nmd.2012.03.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Revised: 03/02/2012] [Accepted: 03/06/2012] [Indexed: 12/20/2022]
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94
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Abstract
Myotonic Dystrophy Type-2 (DM2) is an autosomal dominant disease caused by the expansion of a CCTG tetraplet repeat. It is a multisystemic disorder, affecting skeletal muscles, the heart, the eye, the central nervous system and the endocrine system. Since microRNA (miRNA) expression is disrupted in Myotonic Dystrophy Type-1 and many other myopathies, miRNAs deregulation was studied in skeletal muscle biopsies of 13 DM2 patients and 13 controls. Eleven miRNAs were deregulated: 9 displayed higher levels compared to controls (miR-34a-5p, miR-34b-3p, miR-34c-5p, miR-146b-5p, miR-208a, miR-221-3p and miR-381), while 4 were decreased (miR-125b-5p, miR-193a-3p, miR-193b-3p and miR-378a-3p). To explore the relevance of DM2 miRNA deregulation, the predicted interactions between miRNA and mRNA were investigated. Global gene expression was analyzed in DM2 and controls and bioinformatic analysis identified more than 1,000 miRNA/mRNA interactions. Pathway and function analysis highlighted the involvement of the miRNA-deregulated mRNAs in multiple aspects of DM2 pathophysiology. In conclusion, the observed miRNA dysregulations may contribute to DM2 pathogenetic mechanisms.
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95
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Franc DT, Muetzel RL, Robinson PR, Rodriguez CP, Dalton JC, Naughton CE, Mueller BA, Wozniak JR, Lim KO, Day JW. Cerebral and muscle MRI abnormalities in myotonic dystrophy. Neuromuscul Disord 2012; 22:483-91. [PMID: 22290140 PMCID: PMC3350604 DOI: 10.1016/j.nmd.2012.01.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2011] [Revised: 01/02/2012] [Accepted: 01/04/2012] [Indexed: 01/18/2023]
Abstract
Pathophysiological mechanisms underlying the clinically devastating CNS features of myotonic dystrophy (DM) remain more enigmatic and controversial than do the muscle abnormalities of this common form of muscular dystrophy. To better define CNS and cranial muscle changes in DM, we used quantitative volumetric and diffusion tensor MRI methods to measure cerebral and masticatory muscle differences between controls (n=5) and adults with either congenital (n=5) or adult onset (n=5) myotonic dystrophy type 1 and myotonic dystrophy type 2 (n=5). Muscle volumes were diminished in DM1 and strongly correlated with reduced white matter integrity and gray matter volume. Moreover, correlation of reduced fractional anisotropy (white matter integrity) and gray matter volume in both DM1 and DM2 suggests that these abnormalities may share a common underlying pathophysiological mechanism. Further quantitative temporal and spatial characterization of these features will help delineate developmental and progressive neurological components of DM, and help determine the causative molecular and cellular mechanisms.
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Affiliation(s)
| | | | | | | | - Joline C. Dalton
- University of Minnesota, Department of Genetics, Cell Biology and Development
| | - Cameron E. Naughton
- University of Minnesota, Department of Genetics, Cell Biology and Development
| | | | | | | | - John W. Day
- University of Minnesota, Department of Genetics, Cell Biology and Development
- University of Minnesota, Department of Neurology
- University of Minnesota, Department of Pediatrics
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96
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Kaminsky P, Pruna L. [A genetic systemic disease: clinical description of type 1 myotonic dystrophy in adults]. Rev Med Interne 2012; 33:514-8. [PMID: 22572587 DOI: 10.1016/j.revmed.2012.03.355] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 03/31/2012] [Indexed: 01/06/2023]
Abstract
Type 1 myotonic dystrophy is an autosomal dominant inherited disorder related to the expansion of a trinucleotide (CTG) repeat in the exon 15 in the 3'-untranslated region of the myotonic dystrophy protein kinase (DMPK) gene. Mutant transcripts containing an expanded CUG repeat are retained in nuclear foci and cause numerous dysfunctions by interfering with biogenesis of other mRNAs. Prominent clinical features are progressive muscular weakness and myotonia, which affect skeletal muscles but also white muscles leading to digestive, urinary and obstetrical disorders. Functional prognosis correlates with motor handicap and vital prognosis is linked to cardiac rhythm disturbances and conduction defects due to progressive subendocardial fibrosis, and to complex respiratory dysfunctions, which associate restrictive lung disease, involvement of the central inspiratory pathway, and sleep apnea. Other clinical features are lens opacity, glucose intolerance, metabolic syndrome, several endocrine disorders (gonadal deficiency, hyperparathydoidism), or immunoglobulin deficiency due to immunoglobulin G hypercatabolism. Life expectancy is reduced in myotonic dystrophy, and death is mainly caused by respiratory complications, but also by cardiac arrhythmias. Moreover, an abnormal incidence of tumors has been reported. Therefore, myotonic dystrophy does not only concern neurologists but a multidisciplinary approach is necessary, including at least pneumologist, cardiologist, and physiotherapist. General internists should also be implicated, not only in the initial diagnosis step, but also in the diagnosis of complications and their treatments.
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Affiliation(s)
- P Kaminsky
- Service de médecine interne orientée vers les maladies orphelines et systémiques, pôle des spécialités médicales, centre de référence des maladies neuromusculaires de Nancy, centre hospitalier universitaire de Nancy, hôpitaux de Brabois, rue du Morvan, 54511 Vandœuvre cedex, France
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97
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Four parameters increase the sensitivity and specificity of the exon array analysis and disclose 25 novel aberrantly spliced exons in myotonic dystrophy. J Hum Genet 2012; 57:368-74. [PMID: 22513715 DOI: 10.1038/jhg.2012.37] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Myotonic dystrophy type 1 (DM1) is an RNA gain-of-function disorder in which abnormally expanded CTG repeats of DMPK sequestrate a splicing trans-factor MBNL1 and upregulate another splicing trans-factor CUGBP1. To identify a diverse array of aberrantly spliced genes, we performed the exon array analysis of DM1 muscles. We analyzed 72 exons by RT-PCR and found that 27 were aberrantly spliced, whereas 45 were not. Among these, 25 were novel and especially splicing aberrations of LDB3 exon 4 and TTN exon 45 were unique to DM1. Retrospective analysis revealed that four parameters efficiently detect aberrantly spliced exons: (i) the signal intensity is high; (ii) the ratio of probe sets with reliable signal intensities (that is, detection above background P-value=0.000) is high within a gene; (iii) the splice index (SI) is high; and (iv) SI is deviated from SIs of the other exons that can be estimated by calculating the deviation value (DV). Application of the four parameters gave rise to a sensitivity of 77.8% and a specificity of 95.6% in our data set. We propose that calculation of DV, which is unique to our analysis, is of particular importance in analyzing the exon array data.
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98
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Rinaldi F, Terracciano C, Pisani V, Massa R, Loro E, Vergani L, Di Girolamo S, Angelini C, Gourdon G, Novelli G, Botta A. Aberrant splicing and expression of the non muscle myosin heavy-chain gene MYH14 in DM1 muscle tissues. Neurobiol Dis 2012; 45:264-71. [DOI: 10.1016/j.nbd.2011.08.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 07/25/2011] [Accepted: 08/03/2011] [Indexed: 10/17/2022] Open
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99
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Tang ZZ, Yarotskyy V, Wei L, Sobczak K, Nakamori M, Eichinger K, Moxley RT, Dirksen RT, Thornton CA. Muscle weakness in myotonic dystrophy associated with misregulated splicing and altered gating of Ca(V)1.1 calcium channel. Hum Mol Genet 2011; 21:1312-24. [PMID: 22140091 DOI: 10.1093/hmg/ddr568] [Citation(s) in RCA: 123] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Myotonic dystrophy type 1 and type 2 (DM1 and DM2) are genetic diseases in which mutant transcripts containing expanded CUG or CCUG repeats cause cellular dysfunction by altering the processing or metabolism of specific mRNAs and miRNAs. The toxic effects of mutant RNA are mediated partly through effects on proteins that regulate alternative splicing. Here we show that alternative splicing of exon 29 (E29) of Ca(V)1.1, a calcium channel that controls skeletal muscle excitation-contraction coupling, is markedly repressed in DM1 and DM2. The extent of E29 skipping correlated with severity of weakness in tibialis anterior muscle of DM1 patients. Two splicing factors previously implicated in DM1, MBNL1 and CUGBP1, participated in the regulation of E29 splicing. In muscle fibers of wild-type mice, the Ca(V)1.1 channel conductance and voltage sensitivity were increased by splice-shifting oligonucleotides that induce E29 skipping. In contrast to human DM1, expression of CUG-expanded RNA caused only a modest increase in E29 skipping in mice. However, forced skipping of E29 in these mice, to levels approaching those observed in human DM1, aggravated the muscle pathology as evidenced by increased central nucleation. Together, these results indicate that DM-associated splicing defects alter Ca(V)1.1 function, with potential for exacerbation of myopathy.
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Affiliation(s)
- Zhen Zhi Tang
- Department of Neurology, University of Rochester Medical Center, Rochester, NY 14642, USA
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100
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Sewry CA, Quinlivan RCM, Squier W, Morris GE, Holt I. A rapid immunohistochemical test to distinguish congenital myotonic dystrophy from X-linked myotubular myopathy. Neuromuscul Disord 2011; 22:225-30. [PMID: 22113158 DOI: 10.1016/j.nmd.2011.10.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 09/05/2011] [Accepted: 10/05/2011] [Indexed: 12/11/2022]
Abstract
Severe forms of myotubular myopathy (MTM) and congenital myotonic dystrophy type 1 (CDM), both present as floppy infants with hypotonia, respiratory failure and bulbar insufficiency. Muscle biopsy is often performed as part of the diagnostic process, but these two disorders share very similar histopathological features. It is well documented that CDM muscle has nuclear foci that contain muscleblind-like 1 (MBNL1) protein. In muscle biopsies from eight neonates showing central nuclei, MBNL1 immunolocalisation identified discrete, intensely stained foci in three cases that were subsequently confirmed as CDM by DNA analysis. In the five remaining non-CDM patients and two controls, MBNL1 staining was heterogeneous in nuclei, not as foci. MBNL1 staining patterns in CDM were easily distinguishable from MTM. We suggest that in cases of hypotonia with suspected CDM or MTM, when biopsy has been taken, sections should additionally be stained for MBNL1 to provide a rapid indication of a CDM diagnosis.
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Affiliation(s)
- Caroline A Sewry
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital NHS Foundation Trust, Oswestry, Shropshire SY10 7AG, UK
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