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Gonçalves M, Santos JI, Coutinho MF, Matos L, Alves S. Development of Engineered-U1 snRNA Therapies: Current Status. Int J Mol Sci 2023; 24:14617. [PMID: 37834063 PMCID: PMC10572768 DOI: 10.3390/ijms241914617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 09/22/2023] [Accepted: 09/25/2023] [Indexed: 10/15/2023] Open
Abstract
Splicing of pre-mRNA is a crucial regulatory stage in the pathway of gene expression. The majority of human genes that encode proteins undergo alternative pre-mRNA splicing and mutations that affect splicing are more prevalent than previously thought. Targeting aberrant RNA(s) may thus provide an opportunity to correct faulty splicing and potentially treat numerous genetic disorders. To that purpose, the use of engineered U1 snRNA (either modified U1 snRNAs or exon-specific U1s-ExSpeU1s) has been applied as a potentially therapeutic strategy to correct splicing mutations, particularly those affecting the 5' splice-site (5'ss). Here we review and summarize a vast panoply of studies that used either modified U1 snRNAs or ExSpeU1s to mediate gene therapeutic correction of splicing defects underlying a considerable number of genetic diseases. We also focus on the pre-clinical validation of these therapeutic approaches both in vitro and in vivo, and summarize the main obstacles that need to be overcome to allow for their successful translation to clinic practice in the future.
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Affiliation(s)
- Mariana Gonçalves
- Research and Development Unit, Department of Human Genetics, National Institute of Health Doutor Ricardo Jorge, INSA I.P., Rua Alexandre Herculano, 321, 4000-055 Porto, Portugal; (M.G.); (J.I.S.); (M.F.C.); (L.M.)
- Center for the Study of Animal Science, Institute of Sciences, Technologies and Agro-Environment, CECA-ICETA, University of Porto, Praça Gomes Teixeira, Apartado 55142, 4051-401 Porto, Portugal
- Associate Laboratory for Animal and Veterinary Sciences, AL4AnimalS, Faculty of Veterinary Medicine, University of Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
- Centre for the Research and Technology of Agro-Environmental and Biological Sciences, CITAB, Inov4Agro, University of Trás-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal
| | - Juliana Inês Santos
- Research and Development Unit, Department of Human Genetics, National Institute of Health Doutor Ricardo Jorge, INSA I.P., Rua Alexandre Herculano, 321, 4000-055 Porto, Portugal; (M.G.); (J.I.S.); (M.F.C.); (L.M.)
- Center for the Study of Animal Science, Institute of Sciences, Technologies and Agro-Environment, CECA-ICETA, University of Porto, Praça Gomes Teixeira, Apartado 55142, 4051-401 Porto, Portugal
- Associate Laboratory for Animal and Veterinary Sciences, AL4AnimalS, Faculty of Veterinary Medicine, University of Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
- Biology Department, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal
| | - Maria Francisca Coutinho
- Research and Development Unit, Department of Human Genetics, National Institute of Health Doutor Ricardo Jorge, INSA I.P., Rua Alexandre Herculano, 321, 4000-055 Porto, Portugal; (M.G.); (J.I.S.); (M.F.C.); (L.M.)
- Center for the Study of Animal Science, Institute of Sciences, Technologies and Agro-Environment, CECA-ICETA, University of Porto, Praça Gomes Teixeira, Apartado 55142, 4051-401 Porto, Portugal
- Associate Laboratory for Animal and Veterinary Sciences, AL4AnimalS, Faculty of Veterinary Medicine, University of Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Liliana Matos
- Research and Development Unit, Department of Human Genetics, National Institute of Health Doutor Ricardo Jorge, INSA I.P., Rua Alexandre Herculano, 321, 4000-055 Porto, Portugal; (M.G.); (J.I.S.); (M.F.C.); (L.M.)
- Center for the Study of Animal Science, Institute of Sciences, Technologies and Agro-Environment, CECA-ICETA, University of Porto, Praça Gomes Teixeira, Apartado 55142, 4051-401 Porto, Portugal
- Associate Laboratory for Animal and Veterinary Sciences, AL4AnimalS, Faculty of Veterinary Medicine, University of Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Sandra Alves
- Research and Development Unit, Department of Human Genetics, National Institute of Health Doutor Ricardo Jorge, INSA I.P., Rua Alexandre Herculano, 321, 4000-055 Porto, Portugal; (M.G.); (J.I.S.); (M.F.C.); (L.M.)
- Center for the Study of Animal Science, Institute of Sciences, Technologies and Agro-Environment, CECA-ICETA, University of Porto, Praça Gomes Teixeira, Apartado 55142, 4051-401 Porto, Portugal
- Associate Laboratory for Animal and Veterinary Sciences, AL4AnimalS, Faculty of Veterinary Medicine, University of Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
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Covello G, Ibrahim GH, Bacchi N, Casarosa S, Denti MA. Exon Skipping Through Chimeric Antisense U1 snRNAs to Correct Retinitis Pigmentosa GTPase-Regulator ( RPGR) Splice Defect. Nucleic Acid Ther 2022; 32:333-349. [PMID: 35166581 PMCID: PMC9416563 DOI: 10.1089/nat.2021.0053] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Inherited retinal dystrophies are caused by mutations in more than 250 genes, each of them carrying several types of mutations that can lead to different clinical phenotypes. Mutations in Retinitis Pigmentosa GTPase-Regulator (RPGR) cause X-linked Retinitis pigmentosa (RP). A nucleotide substitution in intron 9 of RPGR causes the increase of an alternatively spliced isoform of the mature mRNA, bearing exon 9a (E9a). This introduces a stop codon, leading to truncation of the protein. Aiming at restoring impaired gene expression, we developed an antisense RNA-based therapeutic approach for the skipping of RPGR E9a. We designed a set of specific U1 antisense snRNAs (U1_asRNAs) and tested their efficacy in vitro, upon transient cotransfection with RPGR minigene reporter systems in HEK-293T, 661W, and PC-12 cell lines.
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Affiliation(s)
- Giuseppina Covello
- RNA Biology and Biotechnology Laboratory, Department of Cellular, Computational and Integrative Biology - CIBIO, University of Trento, Trento, Italy
| | - Gehan H Ibrahim
- Department of Medical Biochemistry, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Niccolò Bacchi
- RNA Biology and Biotechnology Laboratory, Department of Cellular, Computational and Integrative Biology - CIBIO, University of Trento, Trento, Italy
| | - Simona Casarosa
- Neural Development and Regeneration Laboratory, Department of Cellular, Computational and Integrative Biology - CIBIO, University of Trento, Trento, Italy.,Centre for Medical Science - CIS Med, University of Trento, Trento, Italy.,CNR Neuroscience Institute, Pisa, Italy
| | - Michela Alessandra Denti
- RNA Biology and Biotechnology Laboratory, Department of Cellular, Computational and Integrative Biology - CIBIO, University of Trento, Trento, Italy.,CNR Neuroscience Institute, Pisa, Italy
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Sengupta K, Mishra MK, Loro E, Spencer MJ, Pyle AD, Khurana TS. Genome Editing-Mediated Utrophin Upregulation in Duchenne Muscular Dystrophy Stem Cells. MOLECULAR THERAPY. NUCLEIC ACIDS 2020; 22:500-509. [PMID: 33230452 PMCID: PMC7554652 DOI: 10.1016/j.omtn.2020.08.031] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 08/25/2020] [Indexed: 12/26/2022]
Abstract
Utrophin upregulation is considered a promising therapeutic strategy for Duchenne muscular dystrophy (DMD). A number of microRNAs (miRNAs) post-transcriptionally regulate utrophin expression by binding their cognate sites in the 3′ UTR. Previously we have shown that miRNA: UTRN repression can be alleviated using miRNA let-7c site blocking oligonucleotides (SBOs) to achieve utrophin upregulation and functional improvement in mdx mice. Here, we used CRISPR/Cas9-mediated genome editing to delete five miRNA binding sites (miR-150, miR-296-5p, miR-133b, let-7c, miR-196b) clustered in a 500 bp inhibitory miRNA target region (IMTR) within the UTRN 3′ UTR, for achieving higher expression of endogenous utrophin. Deleting the UTRN IMTR in DMD patient-derived human induced pluripotent stem cells (DMD-hiPSCs) resulted in ca. 2-fold higher levels of utrophin protein. Differentiation of the UTRN edited DMD-hiPSCs (UTRNΔIMTR) by MyoD overexpression resulted in increased sarcolemmal α-sarcoglycan staining consistent with improved dystrophin glycoprotein complex (DGC) restoration. These results demonstrate that CRISPR/Cas9-based UTRN genome editing offers a novel utrophin upregulation therapeutic strategy applicable to all DMD patients, irrespective of the dystrophin mutation status.
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Affiliation(s)
- Kasturi Sengupta
- Department of Physiology and Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Manoj K Mishra
- Department of Physiology and Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Emanuele Loro
- Department of Physiology and Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Melissa J Spencer
- Molecular Biology Institute, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA 90095, USA.,Department of Neurology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - April D Pyle
- Molecular Biology Institute, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA 90095, USA.,Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Tejvir S Khurana
- Department of Physiology and Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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Coutinho MF, Matos L, Santos JI, Alves S. RNA Therapeutics: How Far Have We Gone? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1157:133-177. [PMID: 31342441 DOI: 10.1007/978-3-030-19966-1_7] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In recent years, the RNA molecule became one of the most promising targets for therapeutic intervention. Currently, a large number of RNA-based therapeutics are being investigated both at the basic research level and in late-stage clinical trials. Some of them are even already approved for treatment. RNA-based approaches can act at pre-mRNA level (by splicing modulation/correction using antisense oligonucleotides or U1snRNA vectors), at mRNA level (inhibiting gene expression by siRNAs and antisense oligonucleotides) or at DNA level (by editing mutated sequences through the use of CRISPR/Cas). Other RNA approaches include the delivery of in vitro transcribed (IVT) mRNA or the use of oligonucleotides aptamers. Here we review these approaches and their translation into clinics trying to give a brief overview also on the difficulties to its application as well as the research that is being done to overcome them.
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Affiliation(s)
- Maria Francisca Coutinho
- Department of Human Genetics, National Institute of Health Doutor Ricardo Jorge, Porto, Portugal
| | - Liliana Matos
- Department of Human Genetics, National Institute of Health Doutor Ricardo Jorge, Porto, Portugal
| | - Juliana Inês Santos
- Department of Human Genetics, National Institute of Health Doutor Ricardo Jorge, Porto, Portugal
| | - Sandra Alves
- Department of Human Genetics, National Institute of Health Doutor Ricardo Jorge, Porto, Portugal.
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5
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Shahnoor N, Siebers EM, Brown KJ, Lawlor MW. Pathological Issues in Dystrophinopathy in the Age of Genetic Therapies. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2018; 14:105-126. [PMID: 30148687 DOI: 10.1146/annurev-pathmechdis-012418-012945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Dystrophinopathy is a class of genetic skeletal muscle disease characterized by myofiber degeneration and regeneration due to insufficient levels or functioning of dystrophin. Pathological evaluation for dystrophinopathy includes the identification of dystrophic skeletal muscle pathology and the immunohistochemical evaluation of dystrophin epitopes, but biopsies have become rare in recent years. However, the evaluation of dystrophin expression in the research setting has become critically important due to recent advances in genetic therapies, including exon skipping and gene therapy. Given the number of these therapies under evaluation in patients, it is likely that the traditional methods of evaluating dystrophinopathy will need to evolve in the near future. This review discusses current muscle biopsy diagnostic practices in dystrophinopathy and further focuses on how these practices have evolved in the context of therapeutic interventions for dystrophinopathy.
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Affiliation(s)
- Nazima Shahnoor
- Department of Pathology and Laboratory Medicine, and Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA; , ,
| | - Emily M Siebers
- Department of Pathology and Laboratory Medicine, and Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA; , ,
| | - Kristy J Brown
- Solid Biosciences, Inc., Cambridge, Massachusetts 02139, USA;
| | - Michael W Lawlor
- Department of Pathology and Laboratory Medicine, and Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA; , ,
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Godfrey C, Desviat LR, Smedsrød B, Piétri-Rouxel F, Denti MA, Disterer P, Lorain S, Nogales-Gadea G, Sardone V, Anwar R, El Andaloussi S, Lehto T, Khoo B, Brolin C, van Roon-Mom WM, Goyenvalle A, Aartsma-Rus A, Arechavala-Gomeza V. Delivery is key: lessons learnt from developing splice-switching antisense therapies. EMBO Mol Med 2017; 9:545-557. [PMID: 28289078 PMCID: PMC5412803 DOI: 10.15252/emmm.201607199] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The use of splice‐switching antisense therapy is highly promising, with a wealth of pre‐clinical data and numerous clinical trials ongoing. Nevertheless, its potential to treat a variety of disorders has yet to be realized. The main obstacle impeding the clinical translation of this approach is the relatively poor delivery of antisense oligonucleotides to target tissues after systemic delivery. We are a group of researchers closely involved in the development of these therapies and would like to communicate our discussions concerning the validity of standard methodologies currently used in their pre‐clinical development, the gaps in current knowledge and the pertinent challenges facing the field. We therefore make recommendations in order to focus future research efforts and facilitate a wider application of therapeutic antisense oligonucleotides.
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Affiliation(s)
- Caroline Godfrey
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Lourdes R Desviat
- Centro de Biología Molecular Severo Ochoa UAM-CSIC, CIBERER, IdiPaz, Universidad Autónoma de Madrid, Madrid, Spain
| | - Bård Smedsrød
- Department of Medical Biology, University of Tromsø, Tromsø, Norway
| | | | - Michela A Denti
- Centre for Integrative Biology, University of Trento, Trento, Italy
| | - Petra Disterer
- Centre for Amyloidosis and Acute Phase Proteins, Division of Medicine, University College London, London, UK
| | - Stéphanie Lorain
- UPMC, INSERM, UMRS 974, CNRS FRE 3617, Institut de Myologie, Paris, France
| | - Gisela Nogales-Gadea
- Grup d'Investigació en Malalties Neuromusculars i Neuropediatriques, Institut d' Investigació en Ciències de la Salut Germans Trias i Pujol, Badalona Barcelona, Spain
| | - Valentina Sardone
- Dubowitz Neuromuscular Centre and Developmental Neuroscience Programme, Institute of Child Health, University College London, London, UK
| | - Rayan Anwar
- Drug Discovery Informatics Lab, Qasemi-Research Center, Al-Qasemi Academic College, Baka El-Garbiah, Israel.,Drug Discovery and Development Laboratory, Institute of Applied Research, Galilee Society, Shefa-Amr, Israel
| | - Samir El Andaloussi
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.,Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden
| | - Taavi Lehto
- Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden.,Institute of Technology, University of Tartu, Tartu, Estonia
| | - Bernard Khoo
- Centre for Neuroendocrinology, Division of Medicine, University College London, London, UK
| | - Camilla Brolin
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | | | - Aurélie Goyenvalle
- INSERM U1179, UFR des sciences de la santé, Université Versailles Saint Quentin, Montigny-le-Bretonneux, France
| | - Annemieke Aartsma-Rus
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
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7
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Therapeutic advances in musculoskeletal AAV targeting approaches. Curr Opin Pharmacol 2017; 34:56-63. [PMID: 28743034 DOI: 10.1016/j.coph.2017.07.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 06/24/2017] [Accepted: 07/07/2017] [Indexed: 12/11/2022]
Abstract
The use of recombinant adeno-associated viruses (rAAVs) is highly prevalent in musculoskeletal gene therapies due to their versatility, high transduction efficiency, natural tropism and vector genome persistence for years. As the largest organ in the body, treatment of skeletal muscle for widespread and sufficient therapeutic gene expression is highly challenging. In addition to disease-specific hurdles, vector genome loss, off-target gene transfer and immune responses to treatment can diminish the overall benefit of rAAV therapies. A variety of approaches have been developed to overcome these challenges and improve musculoskeletal targeting of rAAVs. This review focuses on recent advancements and remaining obstacles in creating optimal rAAV-based therapies for musculoskeletal application.
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Viral Vector-Mediated Antisense Therapy for Genetic Diseases. Genes (Basel) 2017; 8:genes8020051. [PMID: 28134780 PMCID: PMC5333040 DOI: 10.3390/genes8020051] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 01/04/2017] [Accepted: 01/17/2017] [Indexed: 01/16/2023] Open
Abstract
RNA plays complex roles in normal health and disease and is becoming an important target for therapeutic intervention; accordingly, therapeutic strategies that modulate RNA function have gained great interest over the past decade. Antisense oligonucleotides (AOs) are perhaps the most promising strategy to modulate RNA expression through a variety of post binding events such as gene silencing through degradative or non-degradative mechanisms, or splicing modulation which has recently demonstrated promising results. However, AO technology still faces issues like poor cellular-uptake, low efficacy in target tissues and relatively rapid clearance from the circulation which means repeated injections are essential to complete therapeutic efficacy. To overcome these limitations, viral vectors encoding small nuclear RNAs have been engineered to shuttle antisense sequences into cells, allowing appropriate subcellular localization with pre-mRNAs and permanent correction. In this review, we outline the different strategies for antisense therapy mediated by viral vectors and provide examples of each approach. We also address the advantages and limitations of viral vector use, with an emphasis on their clinical application.
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Double-target Antisense U1snRNAs Correct Mis-splicing Due to c.639+861C>T and c.639+919G>A GLA Deep Intronic Mutations. MOLECULAR THERAPY-NUCLEIC ACIDS 2016; 5:e380. [PMID: 27779620 PMCID: PMC5095687 DOI: 10.1038/mtna.2016.88] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 08/22/2016] [Indexed: 12/26/2022]
Abstract
Fabry disease is a rare X-linked lysosomal storage disorder caused by deficiency of the α-galactosidase A (α-Gal A) enzyme, which is encoded by the GLA gene. GLA transcription in humans produces a major mRNA encoding α-Gal A and a minor mRNA of unknown function, which retains a 57-nucleotide-long cryptic exon between exons 4 and 5, bearing a premature termination codon. NM_000169.2:c.639+861C>T and NM_000169.2:c.639+919G>A GLA deep intronic mutations have been described to cause Fabry disease by inducing overexpression of the alternatively spliced mRNA, along with a dramatic decrease in the major one. Here, we built a wild-type GLA minigene and two minigenes that carry mutations c.639+861C>T and c.639+919G>A. Once transfected into cells, the minigenes recapitulate the molecular patterns observed in patients, at the mRNA, protein, and enzymatic level. We constructed a set of specific double-target U1asRNAs to correct c.639+861C>T and c.639+919G>A GLA mutations. Efficacy of U1asRNAs in inducing the skipping of the cryptic exon was evaluated upon their transient co-transfection with the minigenes in COS-1 cells, by real-time polymerase chain reaction (PCR), western blot analysis, and α-Gal A enzyme assay. We identified a set of U1asRNAs that efficiently restored α-Gal A enzyme activity and the correct splicing pathways in reporter minigenes. We also identified a unique U1asRNA correcting both mutations as efficently as the mutation-specific U1asRNAs. Our study proves that an exon skipping-based approach recovering α-Gal A activity in the c.639+861C>T and c.639+919G>A GLA mutations is active.
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The lack of the Celf2a splicing factor converts a Duchenne genotype into a Becker phenotype. Nat Commun 2016; 7:10488. [PMID: 26796035 PMCID: PMC4736020 DOI: 10.1038/ncomms10488] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 12/18/2015] [Indexed: 01/18/2023] Open
Abstract
Substitutions, deletions and duplications in the dystrophin gene lead to either the severe Duchenne muscular dystrophy (DMD) or mild Becker muscular dystrophy depending on whether out-of-frame or in-frame transcripts are produced. We identified a DMD case (GSΔ44) where the correlation between genotype and phenotype is not respected, even if carrying a typical Duchenne mutation (exon 44 deletion) a Becker-like phenotype was observed. Here we report that in this patient, partial restoration of an in-frame transcript occurs by natural skipping of exon 45 and that this is due to the lack of Celf2a, a splicing factor that interacts with exon 45 in the dystrophin pre-mRNA. Several experiments are presented that demonstrate the central role of Celf2a in controlling exon 45 splicing; our data point to this factor as a potential target for the improvement of those DMD therapeutic treatments, which requires exon 45 skipping. Muscular Dystrophy can be caused by mutations in the dystrophin gene, causing the severe Duchenne form or the mild Becker form depending on if the transcript is in or out-of-frame. Here the authors identify a Duchenne-type mutation that gives a Becker-like phenotype due to skipping of exon 45.
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Echigoya Y, Aoki Y, Miskew B, Panesar D, Touznik A, Nagata T, Tanihata J, Nakamura A, Nagaraju K, Yokota T. Long-term efficacy of systemic multiexon skipping targeting dystrophin exons 45-55 with a cocktail of vivo-morpholinos in mdx52 mice. MOLECULAR THERAPY. NUCLEIC ACIDS 2015; 4:e225. [PMID: 25647512 PMCID: PMC4345310 DOI: 10.1038/mtna.2014.76] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 12/12/2014] [Indexed: 01/16/2023]
Abstract
Antisense-mediated exon skipping, which can restore the reading frame, is a most promising therapeutic approach for Duchenne muscular dystrophy. Remaining challenges include the limited applicability to patients and unclear function of truncated dystrophin proteins. Multiexon skipping targeting exons 45–55 at the mutation hotspot of the dystrophin gene could overcome both of these challenges. Previously, we described the feasibility of exons 45–55 skipping with a cocktail of Vivo-Morpholinos in vivo; however, the long-term efficacy and safety of Vivo-Morpholinos remains to be determined. In this study, we examined the efficacy and toxicity of exons 45–55 skipping by intravenous injections of 6 mg/kg 10-Vivo-Morpholino cocktail (0.6 mg/kg each vPMO) every 2 weeks for 18 weeks to dystrophic exon-52 knockout (mdx52) mice. Systemic skipping of the entire exons 45–55 region was induced, and the Western blot analysis exhibited the restoration of 5–27% of normal levels of dystrophin protein in skeletal muscles, accompanied by improvements in histopathology and muscle strength. No obvious immune response and renal and hepatic toxicity were detected at the end-point of the treatment. We demonstrate our new regimen with the 10-Vivo-Morpholino cocktail is effective and safe for long-term repeated systemic administration in the dystrophic mouse model.
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Affiliation(s)
- Yusuke Echigoya
- Department of Medical Genetics, School of Human Development, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Yoshitsugu Aoki
- 1] Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Japan [2] Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Bailey Miskew
- Department of Medical Genetics, School of Human Development, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Dharminder Panesar
- Department of Medical Genetics, School of Human Development, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Aleksander Touznik
- Department of Medical Genetics, School of Human Development, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Tetsuya Nagata
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Japan
| | - Jun Tanihata
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Japan
| | - Akinori Nakamura
- Department of Medicine (Neurology and Rheumatology), Shinshu University School of Medicine, Matsumoto, Japan
| | - Kanneboyina Nagaraju
- Center for Genetic Medicine Research, Children's National Medical Center, Washington DC, USA
| | - Toshifumi Yokota
- 1] Department of Medical Genetics, School of Human Development, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada [2] Muscular Dystrophy Canada Research Chair, Edmonton, Alberta, Canada
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Jarmin S, Kymalainen H, Popplewell L, Dickson G. New developments in the use of gene therapy to treat Duchenne muscular dystrophy. Expert Opin Biol Ther 2013; 14:209-30. [PMID: 24308293 DOI: 10.1517/14712598.2014.866087] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
INTRODUCTION Duchenne muscular dystrophy (DMD) is a lethal X-linked inherited disorder characterised by progressive muscle weakness, wasting and degeneration. Although the gene affected in DMD was identified over 25 years ago, there is still no effective treatment. AREAS COVERED Here we review some of the genetic-based strategies aimed at amelioration of the DMD phenotype. A number of Phase II/III clinical trials of antisense oligonucleotide-induced exon skipping for restoration of the open reading frame (ORF) of the DMD gene have recently been completed. The potential strategies for overcoming the hurdles that appear to prevent exon skipping becoming an effective treatment for DMD currently are discussed. EXPERT OPINION The applicability of exon skipping as a therapy to DMD is restricted and the development of alternative strategies that are more encompassing is needed. The rapid pre-clinical advances that are being made in the field of adeno-associated virus (AAV)-based delivery of micro-dystrophin would address this. The obstacles to be faced with gene replacement strategies would include the need for high viral titres, efficient muscle targeting and avoidance of immune response to vector and transgene. The new emerging field of gene editing could potentially provide permanent correction of the DMD gene and the feasibility of such an approach to DMD is discussed.
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Affiliation(s)
- Susan Jarmin
- Royal Holloway University of London , Egham, Surrey , UK
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Dick E, Kalra S, Anderson D, George V, Ritso M, Laval SH, Barresi R, Aartsma-Rus A, Lochmüller H, Denning C. Exon skipping and gene transfer restore dystrophin expression in human induced pluripotent stem cells-cardiomyocytes harboring DMD mutations. Stem Cells Dev 2013; 22:2714-24. [PMID: 23829870 DOI: 10.1089/scd.2013.0135] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
With an incidence of ∼1:3,500 to 5,000 in male children, Duchenne muscular dystrophy (DMD) is an X-linked disorder in which progressive muscle degeneration occurs and affected boys usually die in their twenties or thirties. Cardiac involvement occurs in 90% of patients and heart failure accounts for up to 40% of deaths. To enable new therapeutics such as gene therapy and exon skipping to be tested in human cardiomyocytes, we produced human induced pluripotent stem cells (hiPSC) from seven patients harboring mutations across the DMD gene. Mutations were retained during differentiation and analysis indicated the cardiomyocytes showed a dystrophic gene expression profile. Antisense oligonucleotide-mediated skipping of exon 51 restored dystrophin expression to ∼30% of normal levels in hiPSC-cardiomyocytes carrying exon 47-50 or 48-50 deletions. Alternatively, delivery of a dystrophin minigene to cardiomyocytes with a deletion in exon 35 or a point mutation in exon 70 allowed expression levels similar to those seen in healthy cells. This demonstrates that DMD hiPSC-cardiomyocytes provide a novel tool to evaluate whether new therapeutics can restore dystrophin expression in the heart.
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Affiliation(s)
- Emily Dick
- 1 Wolfson Centre for Stem Cells, Tissue Engineering and Modelling (STEM), Centre for Biomolecular Sciences, University of Nottingham , Nottingham, United Kingdom
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14
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Current Challenges and Future Directions in Recombinant AAV-Mediated Gene Therapy of Duchenne Muscular Dystrophy. Pharmaceuticals (Basel) 2013; 6:813-36. [PMID: 24276316 PMCID: PMC3816704 DOI: 10.3390/ph6070813] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 06/14/2013] [Accepted: 06/14/2013] [Indexed: 01/01/2023] Open
Abstract
Various characteristics of adeno-associated virus (AAV)-based vectors with long-term safe expression have made it an exciting transduction tool for clinical gene therapy of Duchenne muscular dystrophy (DMD). Although host immune reactions against the vector as well as transgene products were detected in some instances of the clinical studies, there have been promising observations. Methods of producing AAV vectors for considerable in vivo experimentation and clinical investigations have been developed and a number of studies with AAV vector-mediated muscle transduction were attempted. Notably, an intravenous limb perfusion transduction technique enables extensive transgene expression in the skeletal muscles without noticeable adverse events. Furthermore, cardiac transduction by the rAAV9-microdystrophin would be promising to prevent development of cardiac dysfunction. Recent achievements in transduction technology suggest that long-term transgene expression with therapeutic benefits in DMD treatment would be achieved by the rAAV-mediated transduction strategy with an adequate regimen to regulate host immune response.
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15
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Gedicke-Hornung C, Behrens-Gawlik V, Reischmann S, Geertz B, Stimpel D, Weinberger F, Schlossarek S, Précigout G, Braren I, Eschenhagen T, Mearini G, Lorain S, Voit T, Dreyfus PA, Garcia L, Carrier L. Rescue of cardiomyopathy through U7snRNA-mediated exon skipping in Mybpc3-targeted knock-in mice. EMBO Mol Med 2013; 5:1128-45. [PMID: 23716398 PMCID: PMC3721478 DOI: 10.1002/emmm.201202168] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Revised: 04/19/2013] [Accepted: 04/19/2013] [Indexed: 11/26/2022] Open
Abstract
Exon skipping mediated by antisense oligoribonucleotides (AON) is a promising therapeutic approach for genetic disorders, but has not yet been evaluated for cardiac diseases. We investigated the feasibility and efficacy of viral-mediated AON transfer in a Mybpc3-targeted knock-in (KI) mouse model of hypertrophic cardiomyopathy (HCM). KI mice carry a homozygous G>A transition in exon 6, which results in three different aberrant mRNAs. We identified an alternative variant (Var-4) deleted of exons 5–6 in wild-type and KI mice. To enhance its expression and suppress aberrant mRNAs we designed AON-5 and AON-6 that mask splicing enhancer motifs in exons 5 and 6. AONs were inserted into modified U7 small nuclear RNA and packaged in adeno-associated virus (AAV-U7-AON-5+6). Transduction of cardiac myocytes or systemic administration of AAV-U7-AON-5+6 increased Var-4 mRNA/protein levels and reduced aberrant mRNAs. Injection of newborn KI mice abolished cardiac dysfunction and prevented left ventricular hypertrophy. Although the therapeutic effect was transient and therefore requires optimization to be maintained over an extended period, this proof-of-concept study paves the way towards a causal therapy of HCM.
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Affiliation(s)
- Christina Gedicke-Hornung
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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16
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Douglas AGL, Wood MJA. Splicing therapy for neuromuscular disease. Mol Cell Neurosci 2013; 56:169-85. [PMID: 23631896 PMCID: PMC3793868 DOI: 10.1016/j.mcn.2013.04.005] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 04/19/2013] [Accepted: 04/22/2013] [Indexed: 12/25/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) and spinal muscular atrophy (SMA) are two of the most common inherited neuromuscular diseases in humans. Both conditions are fatal and no clinically available treatments are able to significantly alter disease course in either case. However, by manipulation of pre-mRNA splicing using antisense oligonucleotides, defective transcripts from the DMD gene and from the SMN2 gene in SMA can be modified to once again produce protein and restore function. A large number of in vitro and in vivo studies have validated the applicability of this approach and an increasing number of preliminary clinical trials have either been completed or are under way. Several different oligonucleotide chemistries can be used for this purpose and various strategies are being developed to facilitate increased delivery efficiency and prolonged therapeutic effect. As these novel therapeutic compounds start to enter the clinical arena, attention must also be drawn to the question of how best to facilitate the clinical development of such personalised genetic therapies and how best to implement their provision.
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Affiliation(s)
- Andrew G L Douglas
- Department of Physiology, Anatomy and Genetics, University of Oxford, UK
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17
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Benedetti S, Hoshiya H, Tedesco FS. Repair or replace? Exploiting novel gene and cell therapy strategies for muscular dystrophies. FEBS J 2013; 280:4263-80. [PMID: 23387802 DOI: 10.1111/febs.12178] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 01/24/2013] [Accepted: 01/28/2013] [Indexed: 12/22/2022]
Abstract
Muscular dystrophies are genetic disorders characterized by skeletal muscle wasting and weakness. Although there is no effective therapy, a number of experimental strategies have been developed over recent years and some of them are undergoing clinical investigation. In this review, we highlight recent developments and key challenges for strategies based upon gene replacement and gene/expression repair, including exon-skipping, vector-mediated gene therapy and cell therapy. Therapeutic strategies for different forms of muscular dystrophy are discussed, with an emphasis on Duchenne muscular dystrophy, given the severity and the relatively advanced status of clinical studies for this disease.
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Affiliation(s)
- Sara Benedetti
- Department of Cell and Developmental Biology, University College London, UK
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18
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Abstract
PURPOSE OF REVIEW Duchenne muscular dystrophy is a severe neuromuscular disorder for which there is currently no cure. Years of research have come to fruition during the past 18 months with publications on clinical trials for several gene therapy approaches for Duchenne muscular dystrophy. This review covers the present status of these approaches. RECENT FINDINGS The exon skipping approach is most advanced in the process of clinical application. Encouraging results have been obtained in two systemic clinical trials and further optimization has increased delivery to the heart in animal models. Limitations of the approach are the mutation-specificity and the anticipated requirement for lifelong treatment. Gene therapy by means of gene transfer holds the promise of more long-lasting effects. Results of a first, early-stage gene therapy trial, using viral vectors to deliver a minidystrophin gene, were reported. Animal studies suggest that it may be possible to overcome the main challenges currently facing gene therapy (immunogenicity of the vector and systemic body-wide delivery). SUMMARY Significant steps have been made in the development of gene therapy approaches for Duchenne muscular dystrophy. These approaches aim to slow down disease progression, requiring robust outcome measures to assess efficacy.
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Foster H, Popplewell L, Dickson G. Genetic therapeutic approaches for Duchenne muscular dystrophy. Hum Gene Ther 2012; 23:676-87. [PMID: 22647146 DOI: 10.1089/hum.2012.099] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Despite an expansive wealth of research following the discovery of the DMD gene 25 years ago, there is still no curative treatment for Duchenne muscular dystrophy. However, there are currently many promising lines of research, including cell-based therapies and pharmacological reagents to upregulate dystrophin via readthrough of nonsense mutations or by upregulation of the dystrophin homolog utrophin. Here we review genetic-based therapeutic strategies aimed at the amelioration of the DMD phenotype. These include the reintroduction of a copy of the DMD gene into an affected tissue by means of a viral vector; correction of the mutated DMD transcript by antisense oligonucleotide-induced exon skipping to restore the open reading frame; and direct modification of the DMD gene at a chromosomal level through genome editing. All these approaches are discussed in terms of the more recent advances, and the hurdles to be overcome if a comprehensive and effective treatment for DMD is to be found. These hurdles include the need to target all musculature of the body. Therefore any potential treatment would need to be administered systemically. In addition, any treatment needs to have a long-term effect, with the possibility of readministration, while avoiding any potentially detrimental immune response to the vector or transgene.
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Affiliation(s)
- Helen Foster
- School of Biological Sciences, Royal Holloway-University of London, Egham, Surrey TW20 0EX, United Kingdom
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20
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Hoogaars WMH, Mouisel E, Pasternack A, Hulmi JJ, Relizani K, Schuelke M, Schirwis E, Garcia L, Ritvos O, Ferry A, 't Hoen PA, Amthor H. Combined effect of AAV-U7-induced dystrophin exon skipping and soluble activin Type IIB receptor in mdx mice. Hum Gene Ther 2012; 23:1269-79. [PMID: 22894762 DOI: 10.1089/hum.2012.056] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Adeno-associated virus (AAV)-U7-mediated skipping of dystrophin-exon-23 restores dystrophin expression and muscle function in the mdx mouse model of Duchenne muscular dystrophy. Soluble activin receptor IIB (sActRIIB-Fc) inhibits signaling of myostatin and homologous molecules and increases muscle mass and function of wild-type and mdx mice. We hypothesized that combined treatment with AAV-U7 and sActRIIB-Fc may synergistically improve mdx muscle function. Bioactivity of sActRIIB-Fc on skeletal muscle was first demonstrated in wild-type mice. In mdx mice we show that AAV-U7-mediated dystrophin restoration improved specific muscle force and resistance to eccentric contractions when applied alone. Treatment of mdx mice with sActRIIB-Fc increased body weight, muscle mass and myofiber size, but had little effect on muscle function. Combined treatment stimulated muscle growth comparable to the effect of sActRIIB-Fc alone and dystrophin rescue was similar to AAV-U7 alone. Moreover, combined treatment improved maximal tetanic force and the resistance to eccentric contraction to similar extent as AAV-U7 alone. In conclusion, combination of dystrophin exon skipping with sActRIIB-Fc brings together benefits of each treatment; however, we failed to evidence a clear synergistic effect on mdx muscle function.
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Affiliation(s)
- Willem M H Hoogaars
- Leiden University Medical Center (LUMC), Department of Human Genetics, 2333 ZC Leiden, The Netherlands
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21
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Exon 45 skipping through U1-snRNA antisense molecules recovers the Dys-nNOS pathway and muscle differentiation in human DMD myoblasts. Mol Ther 2012; 20:2134-42. [PMID: 22968481 DOI: 10.1038/mt.2012.178] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Exon skipping has been demonstrated to be a successful strategy for the gene therapy of Duchenne muscular dystrophy (DMD): the rational being to convert severe Duchenne forms into milder Becker ones. Here, we show the selection of U1 snRNA-antisense constructs able to confer effective rescue of dystrophin synthesis in a Δ44 Duchenne genetic background, through skipping of exon 45; moreover, we demonstrate that the resulting dystrophin is able to recover timing of myogenic marker expression, to relocalize neuronal nitric oxide synthase (nNOS) and to rescue expression of miRNAs previously shown to be sensitive to the Dystrophin-nNOS-HDAC2 pathway. Becker mutations display different phenotypes, likely depending on whether the shorter protein is able to reconstitute the wide range of wild-type functions. Among them, efficient assembly of the dystrophin-associated protein complex (DAPC) and nNOS localization are important. Comparing different Becker deletions we demonstrate the correlation between the ability of the mutant dystrophin to relocalize nNOS and the expression levels of two miRNAs, miR-1 and miR29c, known to be involved in muscle homeostasis and to be controlled by the Dys-nNOS-HDAC2 pathway.
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22
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Bish LT, Sleeper MM, Forbes SC, Wang B, Reynolds C, Singletary GE, Trafny D, Morine KJ, Sanmiguel J, Cecchini S, Virag T, Vulin A, Beley C, Bogan J, Wilson JM, Vandenborne K, Kornegay JN, Walter GA, Kotin RM, Garcia L, Sweeney HL. Long-term restoration of cardiac dystrophin expression in golden retriever muscular dystrophy following rAAV6-mediated exon skipping. Mol Ther 2012; 20:580-9. [PMID: 22146342 PMCID: PMC3293605 DOI: 10.1038/mt.2011.264] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Accepted: 11/09/2011] [Indexed: 12/23/2022] Open
Abstract
Although restoration of dystrophin expression via exon skipping in both cardiac and skeletal muscle has been successfully demonstrated in the mdx mouse, restoration of cardiac dystrophin expression in large animal models of Duchenne muscular dystrophy (DMD) has proven to be a challenge. In large animals, investigators have focused on using intravenous injection of antisense oligonucleotides (AO) to mediate exon skipping. In this study, we sought to optimize restoration of cardiac dystrophin expression in the golden retriever muscular dystrophy (GRMD) model using percutaneous transendocardial delivery of recombinant AAV6 (rAAV6) to deliver a modified U7 small nuclear RNA (snRNA) carrying antisense sequence to target the exon splicing enhancers of exons 6 and 8 and correct the disrupted reading frame. We demonstrate restoration of cardiac dystrophin expression at 13 months confirmed by reverse transcription-PCR (RT-PCR) and immunoblot as well as membrane localization by immunohistochemistry. This was accompanied by improved cardiac function as assessed by cardiac magnetic resonance imaging (MRI). Percutaneous transendocardial delivery of rAAV6 expressing a modified U7 exon skipping construct is a safe, effective method for restoration of dystrophin expression and improvement of cardiac function in the GRMD canine and may be easily translatable to human DMD patients.
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Affiliation(s)
- Lawrence T Bish
- Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
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23
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Verhaart IEC, Heemskerk H, Karnaoukh TG, Kolfschoten IGM, Vroon A, van Ommen GJB, van Deutekom JCT, Aartsma-Rus A. Prednisolone treatment does not interfere with 2'-O-methyl phosphorothioate antisense-mediated exon skipping in Duchenne muscular dystrophy. Hum Gene Ther 2012; 23:262-73. [PMID: 22017442 DOI: 10.1089/hum.2011.127] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
In Duchenne muscular dystrophy (DMD), dystrophin deficiency leading to progressive muscular degeneration is caused by frame-shifting mutations in the DMD gene. Antisense oligonucleotides (AONs) aim to restore the reading frame by skipping of a specific exon(s), thereby allowing the production of a shorter, but semifunctional protein, as is found in the mostly more mildly affected patients with Becker muscular dystrophy. AONs are currently being investigated in phase 3 placebo-controlled clinical trials. Most of the participating patients are treated symptomatically with corticosteroids (mainly predniso[lo]ne) to stabilize the muscle fibers, which might affect the uptake and/or efficiency of AONs. Therefore the effect of prednisolone on 2'-O-methyl phosphorothioate AON efficacy in patient-derived cultured muscle cells and the mdx mouse model (after local and systemic AON treatment) was assessed in this study. Both in vitro and in vivo skip efficiency and biomarker expression were comparable between saline- and prednisolone-cotreated cells and mice. After systemic exon 23-specific AON (23AON) treatment for 8 weeks, dystrophin was detectable in all treated mice. Western blot analyses indicated slightly higher dystrophin levels in prednisolone-treated mice, which might be explained by better muscle condition and consequently more target dystrophin pre-mRNA. In addition, fibrotic and regeneration biomarkers were normalized to some extent in prednisolone- and/or 23AON-treated mice. Overall these results show that the use of prednisone forms no barrier to participation in clinical trials with AONs.
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Affiliation(s)
- Ingrid E C Verhaart
- Department of Human Genetics, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
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24
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Abstract
The extracellular matrix (ECM) provides a solid scaffold and signals to cells through ECM receptors. The cell-matrix interactions are crucial for normal biological processes and when disrupted they may lead to pathological processes. In particular, the biological importance of ECM-cell membrane-cytoskeleton interactions in skeletal muscle is accentuated by the number of inherited muscle diseases caused by mutations in proteins conferring these interactions. In this review we introduce laminins, collagens, dystroglycan, integrins, dystrophin and sarcoglycans. Mutations in corresponding genes cause various forms of muscular dystrophy. The muscle disorders are presented as well as advances toward the development of treatment.
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Affiliation(s)
- Virginie Carmignac
- Muscle Biology Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
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25
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Lu QL, Wu B. Systemic delivery of antisense oligomer in animal models and its implications for treating DMD. Methods Mol Biol 2012; 867:393-405. [PMID: 22454075 DOI: 10.1007/978-1-61779-767-5_25] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Antisense oligomer (AO)-mediated splicing modulation for treating DMD demands a systemic administration of AOs as pharmacological drugs to achieve effective prevention of disease progression and to improve quality and longevity of patient life. Three routes, namely, intravenous injection (IV), intraperitoneal injection (IP), and subcutaneous injections (SC), of systemic delivery of AOs have been examined in animal models, and two of them, IV and SC, are being applied in the ongoing clinical trials. The main barrier for systemic treatment with unmodified AO of both chemistries, 2'-O methyl Phosphorothioate RNA and phosphorodiamidate morpholino, is the high degree of variation in exon skipping efficiency both between body-wide muscles and within individual muscle seen in mouse models. AO therapy will likely critically depend on adequate dosing regimens to achieve therapeutic effect.
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Affiliation(s)
- Qi Long Lu
- McColl-Lockwood Laboratory for Muscular Dystrophy Research, Neuromuscular/ALS Center, Carolinas Medical Center, Charlotte, NC, USA.
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U1 snRNA as an effective vector for stable expression of antisense molecules and for the inhibition of the splicing reaction. Methods Mol Biol 2012; 867:239-57. [PMID: 22454066 DOI: 10.1007/978-1-61779-767-5_16] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
We report the use of the U1 snRNA as a vector for the stable expression of antisense molecules against the splice junctions of specific dystrophin exons. The single-stranded 5' terminus of U1 can be replaced by unrelated sequences as long as 50 nucleotides without affecting both the stability and the ability to assemble into snRNP particles. Effective exon skipping has been obtained for different dystrophin exons by antisense sequences against 5' and 3' splice sites alone or in combination with ESE sequences. The efficacy of these molecules has been studied both in in vitro systems and in animals. In both cases the chimeric molecules, delivered as part of lentiviral or AAV vectors (De Angelis et al. Proc Natl Acad Sci USA 99:9456-9461, 2002; Denti et al. Proc Natl Acad Sci USA 103: 3758-3763, 2006; Denti et al. Hum Gene Ther 17: 565-743, 2006; Denti et al. Hum Gene Ther 19: 601-608, 2008; Incitti et al. Mol Ther 18: 1675-1682, 2010), provided high skipping activity and efficient rescue of dystrophin synthesis. Moreover, the U1-antisense molecules, delivered to mice via systemic injection of recombinant AAV viruses, displayed body wide transduction, long-term expression, dystrophin rescue as well as morphological and functional benefit (Denti et al. Hum Gene Ther 19: 601-608, 2008). In this Chapter we report methods for producing U1-antisense expression cassettes in the backbone of lentiviral constructs and for testing their activity both in patients' derived myoblasts as well as in fibroblasts reprogrammed to muscle differentiation.
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27
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Abstract
Antisense-mediated exon skipping to restore the disrupted dystrophin reading frame is currently in clinical trials for Duchenne muscular dystrophy. This chapter describes the rationale of this approach and gives an overview of in vitro and in vivo experiments with antisense oligonucleotides and antisense genes. Finally, an overview of clinical trials is given and outstanding questions and hurdles are discussed.
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Affiliation(s)
- Annemieke Aartsma-Rus
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
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28
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Bish LT, Sleeper MM, Forbes SC, Morine KJ, Reynolds C, Singletary GE, Trafny D, Pham J, Bogan J, Kornegay JN, Vandenborne K, Walter GA, Sweeney HL. Long-term systemic myostatin inhibition via liver-targeted gene transfer in golden retriever muscular dystrophy. Hum Gene Ther 2011; 22:1499-509. [PMID: 21787232 DOI: 10.1089/hum.2011.102] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a lethal, X-linked recessive disease affecting 1 in 3,500 newborn boys for which there is no effective treatment or cure. One novel strategy that has therapeutic potential for DMD is inhibition of myostatin, a negative regulator of skeletal muscle mass that may also promote fibrosis. Therefore, our goal in this study was to evaluate systemic myostatin inhibition in the golden retriever model of DMD (GRMD). GRMD canines underwent liver-directed gene transfer of a self-complementary adeno-associated virus type 8 vector designed to express a secreted dominant-negative myostatin peptide (n = 4) and were compared with age-matched, untreated GRMD controls (n = 3). Dogs were followed with serial magnetic resonance imaging (MRI) for 13 months to assess cross-sectional area and volume of skeletal muscle, then euthanized so that tissue could be harvested for morphological and histological analysis. We found that systemic myostatin inhibition resulted in increased muscle mass in GRMD dogs as assessed by MRI and confirmed at tissue harvest. We also found that hypertrophy of type IIA fibers was largely responsible for the increased muscle mass and that reductions in serum creatine kinase and muscle fibrosis were associated with long-term myostatin inhibition in GRMD. This is the first report describing the effects of long-term, systemic myostatin inhibition in a large-animal model of DMD, and we believe that the simple and effective nature of our liver-directed gene-transfer strategy makes it an ideal candidate for evaluation as a novel therapeutic approach for DMD patients.
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Affiliation(s)
- Lawrence T Bish
- Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
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29
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van Putten M, Aartsma-Rus A. Opportunities and challenges for the development of antisense treatment in neuromuscular disorders. Expert Opin Biol Ther 2011; 11:1025-37. [PMID: 21510827 DOI: 10.1517/14712598.2011.579098] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
INTRODUCTION Neuromuscular disorders are diseases of the musculature and/or the nervous system, generally leading to loss of muscle function. They are a frequent cause of disability and treatment options are often only symptomatic. Interestingly, for a number of neuromuscular disorders the application of antisense oligonucleotides has therapeutic potential. AREAS COVERED The authors describe how this approach is exploited for different neuromuscular diseases, focusing on literature published in the past 10 years. For each disease the opportunities of this approach, the state of the art, and current challenges are described. EXPERT OPINION A lot of progress has been made in the development of antisense-mediated approaches during recent years and they may become clinically applicable in the near future.
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Affiliation(s)
- Maaike van Putten
- Leiden University Medical Center, Department of Human Genetics, The Netherlands
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30
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Current status of pharmaceutical and genetic therapeutic approaches to treat DMD. Mol Ther 2011; 19:830-40. [PMID: 21468001 DOI: 10.1038/mt.2011.59] [Citation(s) in RCA: 148] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a genetic disease affecting about one in every 3,500 boys. This X-linked pathology is due to the absence of dystrophin in muscle fibers. This lack of dystrophin leads to the progressive muscle degeneration that is often responsible for the death of the DMD patients during the third decade of their life. There are currently no curative treatments for this disease but different therapeutic approaches are being studied. Gene therapy consists of introducing a transgene coding for full-length or a truncated version of dystrophin complementary DNA (cDNA) in muscles, whereas pharmaceutical therapy includes the use of chemical/biochemical substances to restore dystrophin expression or alleviate the DMD phenotype. Over the past years, many potential drugs were explored. This led to several clinical trials for gentamicin and ataluren (PTC124) allowing stop codon read-through. An alternative approach is to induce the expression of an internally deleted, partially functional dystrophin protein through exon skipping. The vectors and the methods used in gene therapy have been continually improving in order to obtain greater encapsidation capacity and better transduction efficiency. The most promising experimental approaches using pharmaceutical and gene therapies are reviewed in this article.
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31
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Cacchiarelli D, Legnini I, Martone J, Cazzella V, D'Amico A, Bertini E, Bozzoni I. miRNAs as serum biomarkers for Duchenne muscular dystrophy. EMBO Mol Med 2011; 3:258-65. [PMID: 21425469 PMCID: PMC3112257 DOI: 10.1002/emmm.201100133] [Citation(s) in RCA: 210] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 02/18/2011] [Accepted: 02/21/2011] [Indexed: 11/18/2022] Open
Abstract
Dystrophin absence in Duchenne muscular dystrophy (DMD) causes severe muscle degeneration. We describe that, as consequence of fibre damage, specific muscle-miRNAs are released in to the bloodstream of DMD patients and their levels correlate with the severity of the disease. The same miRNAs are abundant also in the blood of mdx mice and recover to wild-type levels in animals ‘cured’ through exon skipping. Even though creatine kinase (CK) blood levels have been utilized as diagnostic markers of several neuromuscular diseases, including DMD, we demonstrate that they correlate less well with the disease severity. Although the analysis of a larger number of patients should allow to obtain more refined correlations with the different stages of disease progression, we propose that miR-1, miR-133, and miR-206 are new and valuable biomarkers for the diagnosis of DMD and possibly also for monitoring the outcomes of therapeutic interventions in humans. Despite many different DMD therapeutic approaches are now entering clinical trials, a unifying method for assessing the benefit of different treatments is still lacking.
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Affiliation(s)
- Davide Cacchiarelli
- Department of Biology and Biotechnology, Institute Pasteur Cenci-Bolognetti and IBPM, Sapienza University of Rome, Italy
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32
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Abstract
INTRODUCTION Antisense oligonucleotides (ASOs) are short synthetic single-stranded DNA sequences that bind to and induce the cleavage of homologous stretches of mRNA sequences. These result in targeted destruction of mRNA and correction of genetic aberrations. ASOs thus can act as drug molecules and potentially rectify many disease conditions. The broad range of applications reported in the literature highlights the advances in the field. AREAS COVERED This review covers different areas in which use of ASOs has been shown to have therapeutic effects. Some drugs in different stages of preclinical and clinical trials are discussed in detail. The problems faced and the strategies to surmount them are also described. The readers will gain an understanding of the recent developments in the field of ASOs with emphasis on their therapeutic applications. They will also become aware of the different strategies used for targeted delivery of ASOs and their stabilization, which may be useful for their work in this field, or in the area of nucleic acid therapeutics in general. EXPERT OPINION The design and application of ASOs for recognition of target mRNA sequences have become a fairly straightforward protocol. The main problem lies in designing ASOs which are stable in in vivo milieu. The delivery and bioavailability of the oligonucleotide to the site of action continue to be hurdles in the development of ASOs and therapeutic molecules.
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Affiliation(s)
- Ravinder Malik
- National Institute of Pharmaceutical Education and Research (NIPER), Department of Biotechnology , Sector 67, S.A.S. Nagar, Punjab 160 062 , India
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Cacchiarelli D, Incitti T, Martone J, Cesana M, Cazzella V, Santini T, Sthandier O, Bozzoni I. miR-31 modulates dystrophin expression: new implications for Duchenne muscular dystrophy therapy. EMBO Rep 2011; 12:136-41. [PMID: 21212803 DOI: 10.1038/embor.2010.208] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 11/12/2010] [Accepted: 11/22/2010] [Indexed: 11/09/2022] Open
Abstract
Duchenne muscular dystrophy (DMD)--which is caused by mutations in the dystrophin gene-is one of the most severe myopathies. Among therapeutic strategies, exon skipping allows the rescue of dystrophin synthesis through the production of a shorter but functional messenger RNA. Here, we report the identification of a microRNA--miR-31--that represses dystrophin expression by targeting its 3' untranslated region. In human DMD myoblasts treated with exon skipping, we demonstrate that miR-31 inhibition increases dystrophin rescue. These results indicate that interfering with miR-31 activity can provide an ameliorating strategy for those DMD therapies that are aimed at efficiently recovering dystrophin synthesis.
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Affiliation(s)
- Davide Cacchiarelli
- Department of Biology and Biotechnology C. Darwin, Institut Pasteur Cenci-Bolognetti and IBPM-Sapienza, University of Rome, Piazzele Aldo Moro 5, Rome 00185, Italy
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Aartsma-Rus A, den Dunnen JT, van Ommen GJB. New insights in gene-derived therapy: the example of Duchenne muscular dystrophy. Ann N Y Acad Sci 2010; 1214:199-212. [PMID: 21121926 DOI: 10.1111/j.1749-6632.2010.05836.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The two therapeutic approaches currently most advanced in clinical trials for Duchenne muscular dystrophy are antisense-mediated exon skipping and forced read-through of premature stop codons. Interestingly, these approaches target the gene product rather than the gene itself. This review will explain the rationale and current state of affairs of these approaches and will then discuss how these gene-derived therapies might also be applicable to other diseases.
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Affiliation(s)
- Annemieke Aartsma-Rus
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands.
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Lu QL, Yokota T, Takeda S, Garcia L, Muntoni F, Partridge T. The status of exon skipping as a therapeutic approach to duchenne muscular dystrophy. Mol Ther 2010; 19:9-15. [PMID: 20978473 DOI: 10.1038/mt.2010.219] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is associated with mutations in the dystrophin gene that disrupt the open reading frame whereas the milder Becker's form is associated with mutations which leave an in-frame mRNA transcript that can be translated into a protein that includes the N- and C- terminal functional domains. It has been shown that by excluding specific exons at, or adjacent to, frame-shifting mutations, open reading frame can be restored to an out-of-frame mRNA, leading to the production of a partially functional Becker-like dystrophin protein. Such targeted exclusion can be achieved by administration of oligonucleotides that are complementary to sequences that are crucial to normal splicing of the exon into the transcript. This principle has been validated in mouse and canine models of DMD with a number of variants of oligonucleotide analogue chemistries and by transduction with adeno-associated virus (AAV)-small nuclear RNA (snRNA) reagents encoding the antisense sequence. Two different oligonucleotide agents are now being investigated in human trials for splicing out of exon 51 with some early indications of success at the biochemical level.
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Affiliation(s)
- Qi-Long Lu
- McColl-Lockwood Laboratory for Muscular Dystrophy Research, Neuromuscular/ALS Center, Carolinas Medical Center, Charlotte, North Carolina, USA
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Cacchiarelli D, Martone J, Girardi E, Cesana M, Incitti T, Morlando M, Nicoletti C, Santini T, Sthandier O, Barberi L, Auricchio A, Musarò A, Bozzoni I. MicroRNAs involved in molecular circuitries relevant for the Duchenne muscular dystrophy pathogenesis are controlled by the dystrophin/nNOS pathway. Cell Metab 2010; 12:341-351. [PMID: 20727829 DOI: 10.1016/j.cmet.2010.07.008] [Citation(s) in RCA: 199] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Revised: 03/23/2010] [Accepted: 06/30/2010] [Indexed: 11/28/2022]
Abstract
In Duchenne muscular dystrophy (DMD) the absence of dystrophin at the sarcolemma delocalizes and downregulates nitric oxide synthase (nNOS); this alters S-nitrosylation of HDAC2 and its chromatin association. We show that the differential HDAC2 nitrosylation state in Duchenne versus wild-type conditions deregulates the expression of a specific subset of microRNA genes. Several circuitries controlled by the identified microRNAs, such as the one linking miR-1 to the G6PD enzyme and the redox state of cell, or miR-29 to extracellular proteins and the fibrotic process, explain some of the DMD pathogenetic traits. We also show that, at variance with other myomiRs, miR-206 escapes from the dystrophin-nNOS control being produced in activated satellite cells before dystrophin expression; in these cells, it contributes to muscle regeneration through repression of the satellite specific factor, Pax7. We conclude that the pathway activated by dystrophin/nNOS controls several important circuitries increasing the robustness of the muscle differentiation program.
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Affiliation(s)
- Davide Cacchiarelli
- Institute Pasteur Cenci-Bolognetti, Department of Genetics and Molecular Biology and IBPM, "SAPIENZA" University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Julie Martone
- Institute Pasteur Cenci-Bolognetti, Department of Genetics and Molecular Biology and IBPM, "SAPIENZA" University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Erika Girardi
- Institute Pasteur Cenci-Bolognetti, Department of Genetics and Molecular Biology and IBPM, "SAPIENZA" University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Marcella Cesana
- Institute Pasteur Cenci-Bolognetti, Department of Genetics and Molecular Biology and IBPM, "SAPIENZA" University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Tania Incitti
- Institute Pasteur Cenci-Bolognetti, Department of Genetics and Molecular Biology and IBPM, "SAPIENZA" University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Mariangela Morlando
- Institute Pasteur Cenci-Bolognetti, Department of Genetics and Molecular Biology and IBPM, "SAPIENZA" University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Carmine Nicoletti
- Department of Histology and Medical Embryology, Interuniversity Institute of Myology, "SAPIENZA" University of Rome, Via A. Scarpa, 14, 00161 Rome, Italy
| | - Tiziana Santini
- Institute Pasteur Cenci-Bolognetti, Department of Genetics and Molecular Biology and IBPM, "SAPIENZA" University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Olga Sthandier
- Institute Pasteur Cenci-Bolognetti, Department of Genetics and Molecular Biology and IBPM, "SAPIENZA" University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Laura Barberi
- Department of Histology and Medical Embryology, Interuniversity Institute of Myology, "SAPIENZA" University of Rome, Via A. Scarpa, 14, 00161 Rome, Italy
| | - Alberto Auricchio
- Telethon Institute of Genetics and Medicine, Via P. Castellino 111, 80131 Napoli, Italy
| | - Antonio Musarò
- Department of Histology and Medical Embryology, Interuniversity Institute of Myology, "SAPIENZA" University of Rome, Via A. Scarpa, 14, 00161 Rome, Italy
| | - Irene Bozzoni
- Institute Pasteur Cenci-Bolognetti, Department of Genetics and Molecular Biology and IBPM, "SAPIENZA" University of Rome, P.le A. Moro 5, 00185 Rome, Italy.
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Accurate quantification of dystrophin mRNA and exon skipping levels in duchenne muscular dystrophy. J Transl Med 2010; 90:1396-402. [PMID: 20458276 DOI: 10.1038/labinvest.2010.98] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Antisense oligonucleotide (AON)-mediated exon skipping aimed at restoring the reading frame is a promising therapeutic approach for Duchenne muscular dystrophy that is currently tested in clinical trials. Numerous AONs have been tested in (patient-derived) cultured muscle cells and the mdx mouse model. The main outcome to measure AON efficiency is usually the exon-skipping percentage, though different groups use different methods to assess these percentages. Here, we compare a series of techniques to quantify exon skipping levels in AON-treated mdx mouse muscle. We compared densitometry of RT-PCR products on ethidium bromide-stained agarose gels, primary and nested RT-PCR followed by bioanalyzer analysis and melting curve analysis. The digital array system (Fluidigm) allows absolute quantification of skipped vs non-skipped transcripts and was used as a reference. Digital array results show that 1 ng of mdx gastrocnemius muscle-derived mRNA contains approximately 1100 dystrophin transcripts and that 665 transcripts are sufficient to determine exon-skipping levels. Quantification using bioanalyzer or densitometric analysis of primary PCR products resulted in values close to those obtained with digital array. The use of the same technique allows comparison between different groups working on exon skipping in the mdx mouse model.
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Aulino P, Berardi E, Cardillo VM, Rizzuto E, Perniconi B, Ramina C, Padula F, Spugnini EP, Baldi A, Faiola F, Adamo S, Coletti D. Molecular, cellular and physiological characterization of the cancer cachexia-inducing C26 colon carcinoma in mouse. BMC Cancer 2010; 10:363. [PMID: 20615237 PMCID: PMC2912868 DOI: 10.1186/1471-2407-10-363] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Accepted: 07/08/2010] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND The majority of cancer patients experience dramatic weight loss, due to cachexia and consisting of skeletal muscle and fat tissue wasting. Cachexia is a negative prognostic factor, interferes with therapy and worsens the patients' quality of life by affecting muscle function. Mice bearing ectopically-implanted C26 colon carcinoma are widely used as an experimental model of cancer cachexia. As part of the search for novel clinical and basic research applications for this experimental model, we characterized novel cellular and molecular features of C26-bearing mice. METHODS A fragment of C26 tumor was subcutaneously grafted in isogenic BALB/c mice. The mass growth and proliferation rate of the tumor were analyzed. Histological and cytofluorometric analyses were used to assess cell death, ploidy and differentiation of the tumor cells. The main features of skeletal muscle atrophy, which were highlighted by immunohistochemical and electron microscopy analyses, correlated with biochemical alterations. Muscle force and resistance to fatigue were measured and analyzed as major functional deficits of the cachectic musculature. RESULTS We found that the C26 tumor, ectopically implanted in mice, is an undifferentiated carcinoma, which should be referred to as such and not as adenocarcinoma, a common misconception. The C26 tumor displays aneuploidy and histological features typical of transformed cells, incorporates BrdU and induces severe weight loss in the host, which is largely caused by muscle wasting. The latter appears to be due to proteasome-mediated protein degradation, which disrupts the sarcomeric structure and muscle fiber-extracellular matrix interactions. A pivotal functional deficit of cachectic muscle consists in increased fatigability, while the reported loss of tetanic force is not statistically significant following normalization for decreased muscle fiber size. CONCLUSIONS We conclude, on the basis of the definition of cachexia, that ectopically-implanted C26 carcinoma represents a well standardized experimental model for research on cancer cachexia. We wish to point out that scientists using the C26 model to study cancer and those using the same model to study cachexia may be unaware of each other's works because they use different keywords; we present strategies to eliminate this gap and discuss the benefits of such an exchange of knowledge.
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Affiliation(s)
- Paola Aulino
- Department of Histology and Medical Embryology, Sapienza University of Rome, Via Scarpa 16, 00161 Rome, Italy
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Exon skipping and duchenne muscular dystrophy therapy: selection of the most active U1 snRNA antisense able to induce dystrophin exon 51 skipping. Mol Ther 2010; 18:1675-82. [PMID: 20551908 DOI: 10.1038/mt.2010.123] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
One promising approach for the gene therapy of Duchenne muscular dystrophy (DMD) is exon skipping. When thinking of possible intervention on human, it is very crucial to identify the most appropriate antisense sequences able to provide the highest possible skipping efficiency. In this article, we compared the exon 51 skipping activity of 10 different antisense molecules, raised against splice junctions and/or exonic splicing enhancers (ESEs), expressed as part of the U1 small nuclear RNA (snRNA). The effectiveness of each construct was tested in human DMD myoblasts carrying the deletion of exons 48-50, which can be treated with skipping of exon 51. Our results show that the highest skipping activity and dystrophin rescue is achieved upon expression of a U1 snRNA-derived antisense molecule targeting exon 51 splice sites in combination with an internal exon sequence. The efficacy of this molecule was further proven on an exon 45-50 deletion background, utilizing patient's fibroblasts transdifferentiated into myoblasts. In this system, we showed that the selected antisense was able to produce 50% skipping of exon 51.
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40
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Spitali P, Heemskerk H, Vossen RHAM, Ferlini A, den Dunnen JT, 't Hoen PAC, Aartsma-Rus A. Accurate quantification of dystrophin mRNA and exon skipping levels in Duchenne Muscular Dystrophy. Lab Invest 2010. [DOI: 10.1038/labinvest.labinvest201098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Malerba A, Thorogood FC, Dickson G, Graham IR. Dosing regimen has a significant impact on the efficiency of morpholino oligomer-induced exon skipping in mdx mice. Hum Gene Ther 2009; 20:955-65. [PMID: 19469709 DOI: 10.1089/hum.2008.157] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a myodegenerative disorder caused primarily by mutations that create premature termination of dystrophin translation. The antisense oligonucleotide approach for skipping dystrophin exons allows restoration of the correct reading frame in the dystrophin transcript, thus producing a shorter protein. A similar approach in humans would result in the conversion of DMD to the milder Becker muscular dystrophy. It has been demonstrated previously that repeated intravascular injection of phosphorodiamidate morpholino oligomers (PMOs) in the mdx mouse induces more dystrophin expression than a single injection, but this approach is costly, and data demonstrating the safety of high doses of systemically injected PMO are unavailable. Furthermore, several publications have demonstrated the efficacy of peptide-conjugated PMOs, but the clinical applicability of such compounds is unclear at this stage. Here, we report that multiple intravascular injections of low doses of naked PMO show significantly more dystrophin-positive fibers in a variety of muscle groups, 8 weeks after administration compared with a single dose of the same total amount. After administration of a total of 200 mg of PMO per kilogram, histological features, such as the cross-sectional area, centronucleation index, and expression of the dystrophin-associated protein complex, showed significant improvement in mice treated by repeated injection. Furthermore, four administrations of just 5 mg/kg induced a significant amount of dystrophin expression. These results clearly demonstrate the key role of the optimization of dosing regimen for the systemic administration of PMO in patients, and support the clinical feasibility of this approach with naked PMO.
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Affiliation(s)
- Alberto Malerba
- School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey, United Kingdom
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42
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Abstract
Muscular dystrophies are individually rare genetic disorders that cause much chronic disability, affecting young children and adults. In the past 20 years, more than 30 genetic types of muscular dystrophy have been defined. During this time, precise diagnosis, genetic counselling, and medical management have improved. These advances in medical practice have occurred while definitive therapies based on an improved knowledge of disease pathogenesis are awaited. A wide range of therapeutic options have been tested in animal models, and some are being tested in clinical trials. Various therapeutic targets are being investigated, from personalised medicines targeting specific mutations and drugs targeting cellular pathways to gene-based and cell-based therapies.
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Affiliation(s)
- Kate Bushby
- Institute of Human Genetics, Newcastle University, Newcastle upon Tyne, UK.
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43
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Le Roy F, Charton K, Lorson CL, Richard I. RNA-targeting approaches for neuromuscular diseases. Trends Mol Med 2009; 15:580-91. [PMID: 19906562 DOI: 10.1016/j.molmed.2009.10.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2009] [Revised: 09/25/2009] [Accepted: 10/08/2009] [Indexed: 12/16/2022]
Abstract
Although most molecular therapy strategies for genetic diseases are based on gene replacement, interesting alternative approaches target RNA. These strategies rely on the modification of the mutated gene's expression in vivo by modulating pre-mRNA splicing, mRNA stability or mRNA translation. Here, we review recent progress using these RNA-based approaches in the field of muscle and muscle-related genetic diseases. Different molecular tools, including modified antisense oligonucleotides, pre-mRNA trans-splicing molecules, ribozymes or chemical compounds have been used successfully on patient cells or animal models of disease. These diverse strategies show tremendous therapeutic potential and several clinical trials have been initiated with Duchenne muscular dystrophy patients with promising results.
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Affiliation(s)
- Florence Le Roy
- Généthon, CNRS/UEVE UMR8587 LAMBE, 1, rue de l'Internationale, 91000 Evry, France
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Jearawiriyapaisarn N, Moulton HM, Sazani P, Kole R, Willis MS. Long-term improvement in mdx cardiomyopathy after therapy with peptide-conjugated morpholino oligomers. Cardiovasc Res 2009; 85:444-53. [PMID: 19815563 DOI: 10.1093/cvr/cvp335] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
AIMS The cardiomyopathy found in Duchenne muscular dystrophy (DMD) is responsible for death due to heart failure in approximately 30% of patients and additionally contributes to many DMD morbidities. Strategies to bypass DMD-causing mutations to allow an increase in body-wide dystrophin have proved promising, but increasing cardiac dystrophin continues to be challenging. The purpose of this study was to determine if therapeutic restoration of cardiac dystrophin improved the significant cardiac hypertrophy and diastolic dysfunction identified in X-linked muscular dystrophy (mdx) dystrophin-null mouse due to a truncation mutation over time after treatment. METHODS AND RESULTS Mice lacking dystrophin due to a truncation mutation (mdx) were given an arginine-rich, cell-penetrating, peptide-conjugated phosphorodiamidate morpholino oligomer (PPMO) that delivered a splice-switching oligonucleotide-mediated exon skipping therapy to restore dystrophin in mdx mice before the development of detectable cardiomyopathy. PPMO successfully restored cardiac dystrophin expression, preserved cardiac sarcolemma integrity, and prevented the development of cardiac pathology that develops in mdx-null mice over time. By echocardiography and Doppler analysis of the mitral valve, we identified that PPMO treatment of mdx mice prevented the cardiac hypertrophy and diastolic dysfunction identified in sham-treated, age-matched mdx mice, characteristic of DMD patients early in the disease process, in as little as 5-6 weeks after the initiation of treatment. Surprisingly, despite the short-term replacement of cardiac dystrophin (<1% present after 12 weeks by immunodetection), PPMO therapy also provided a durable cardiac improvement in cardiac hypertrophy and diastolic dysfunction for up to 7 months after the initiation of treatment. CONCLUSION These results demonstrate for the first time that PPMO-mediated exon skipping therapy early in the course of DMD may effectively prevent or slow down associated cardiac hypertrophy and diastolic dysfunction with significant long-term impact.
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Affiliation(s)
- Natee Jearawiriyapaisarn
- Department of Pharmacology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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Aartsma-Rus A, van Ommen GJB. Progress in therapeutic antisense applications for neuromuscular disorders. Eur J Hum Genet 2009; 18:146-53. [PMID: 19809477 DOI: 10.1038/ejhg.2009.160] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Neuromuscular disorders are a frequent cause of chronic disability in man. They often result from mutations in single genes and are thus, in principle, well suited for gene therapy. However, the tissues involved (muscle and the central nervous system) are post-mitotic, which poses a challenge for most viral vectors. In some cases, alternative approaches may use small molecules, for example, antisense oligonucleotides (AONs). These do not deliver a new gene, but rather modulate existing gene products or alter the utilization of pathways. For Duchenne muscular dystrophy, this approach is in early phase clinical trials, and for two other common neuromuscular disorders (spinal muscular atrophy and myotonic dystrophy), significant preclinical advances have recently been made.
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Affiliation(s)
- Annemieke Aartsma-Rus
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
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46
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Current world literature. Curr Opin Neurol 2009; 22:554-61. [PMID: 19755870 DOI: 10.1097/wco.0b013e3283313b14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Trollet C, Athanasopoulos T, Popplewell L, Malerba A, Dickson G. Gene therapy for muscular dystrophy: current progress and future prospects. Expert Opin Biol Ther 2009; 9:849-66. [DOI: 10.1517/14712590903029164] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Modulation of caspase activity regulates skeletal muscle regeneration and function in response to vasopressin and tumor necrosis factor. PLoS One 2009; 4:e5570. [PMID: 19440308 PMCID: PMC2680623 DOI: 10.1371/journal.pone.0005570] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2009] [Accepted: 04/20/2009] [Indexed: 11/19/2022] Open
Abstract
Muscle homeostasis involves de novo myogenesis, as observed in conditions of acute or chronic muscle damage. Tumor Necrosis Factor (TNF) triggers skeletal muscle wasting in several pathological conditions and inhibits muscle regeneration. We show that intramuscular treatment with the myogenic factor Arg8-vasopressin (AVP) enhanced skeletal muscle regeneration and rescued the inhibitory effects of TNF on muscle regeneration. The functional analysis of regenerating muscle performance following TNF or AVP treatments revealed that these factors exerted opposite effects on muscle function. Principal component analysis showed that TNF and AVP mainly affect muscle tetanic force and fatigue. Importantly, AVP counteracted the effects of TNF on muscle function when delivered in combination with the latter. Muscle regeneration is, at least in part, regulated by caspase activation, and AVP abrogated TNF-dependent caspase activation. The contrasting effects of AVP and TNF in vivo are recapitulated in myogenic cell cultures, which express both PW1, a caspase activator, and Hsp70, a caspase inhibitor. We identified PW1 as a potential Hsp70 partner by screening for proteins interacting with PW1. Hsp70 and PW1 co-immunoprecipitated and co-localized in muscle cells. In vivo Hsp70 protein level was upregulated by AVP, and Hsp70 overexpression counteracted the TNF block of muscle regeneration. Our results show that AVP counteracts the effects of TNF through cross-talk at the Hsp70 level. Therefore, muscle regeneration, both in the absence and in the presence of cytokines may be enhanced by increasing Hsp70 expression.
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Arnett ALH, Chamberlain JR, Chamberlain JS. Therapy for neuromuscular disorders. Curr Opin Genet Dev 2009; 19:290-7. [PMID: 19411172 DOI: 10.1016/j.gde.2009.03.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Revised: 03/17/2009] [Accepted: 03/20/2009] [Indexed: 12/21/2022]
Abstract
Research into therapeutic approaches for both recessive and dominant neuromuscular disorders has made great progress over the past few years. In the field of gene therapy, antisense-mediated exon skipping is being applied to bypass deleterious mutations in the dystrophin gene and restore dystrophin expression in animal models of muscular dystrophy. Approaches for the dominant genetic muscle diseases have turned toward elimination of the mutant gene product with anti-sense oligonucleotide therapy and RNA interference techniques. Refinements of adeno-associated viral vectors and strategies for their delivery are also leading towards future clinical trials. The discovery of new, multipotent cell lineages, some of which possess the ability to successfully engraft muscle following vascular delivery, presents exciting prospects for the field of stem cell therapy. These discoveries represent steady progress towards the development of effective therapies for a wide range of neuromuscular disorders.
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Affiliation(s)
- Andrea L H Arnett
- Medical Scientist Training Program, University of Washington, Seattle, WA 98195-7720, United States.
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50
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Puttini S, Lekka M, Dorchies OM, Saugy D, Incitti T, Ruegg UT, Bozzoni I, Kulik AJ, Mermod N. Gene-mediated restoration of normal myofiber elasticity in dystrophic muscles. Mol Ther 2008; 17:19-25. [PMID: 19002166 DOI: 10.1038/mt.2008.239] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Dystrophin mediates a physical link between the cytoskeleton of muscle fibers and the extracellular matrix, and its absence leads to muscle degeneration and dystrophy. In this article, we show that the lack of dystrophin affects the elasticity of individual fibers within muscle tissue explants, as probed using atomic force microscopy (AFM), providing a sensitive and quantitative description of the properties of normal and dystrophic myofibers. The rescue of dystrophin expression by exon skipping or by the ectopic expression of the utrophin analogue normalized the elasticity of dystrophic muscles, and these effects were commensurate to the functional recovery of whole muscle strength. However, a more homogeneous and widespread restoration of normal elasticity was obtained by the exon-skipping approach when comparing individual myofibers. AFM may thus provide a quantification of the functional benefit of gene therapies from live tissues coupled to single-cell resolution.
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Affiliation(s)
- Stefania Puttini
- Institute of Biotechnology, University of Lausanne, Lausanne, Switzerland
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