301
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Johnson-Kerner BL, Roth L, Greene JP, Wichterle H, Sproule DM. Giant axonal neuropathy: An updated perspective on its pathology and pathogenesis. Muscle Nerve 2014; 50:467-76. [DOI: 10.1002/mus.24321] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/16/2014] [Indexed: 12/15/2022]
Affiliation(s)
- Bethany L. Johnson-Kerner
- Project A.L.S./Jenifer Estess Laboratory for Stem Cell Research; Center for Motor Neuron Biology and Disease, Columbia Stem Cell Initiative, Columbia University College of Physicians and Surgeons; New York New York USA
| | - Lisa Roth
- Project A.L.S./Jenifer Estess Laboratory for Stem Cell Research; Center for Motor Neuron Biology and Disease, Columbia Stem Cell Initiative, Columbia University College of Physicians and Surgeons; New York New York USA
| | - J. Palmer Greene
- Project A.L.S./Jenifer Estess Laboratory for Stem Cell Research; Center for Motor Neuron Biology and Disease, Columbia Stem Cell Initiative, Columbia University College of Physicians and Surgeons; New York New York USA
| | - Hynek Wichterle
- Project A.L.S./Jenifer Estess Laboratory for Stem Cell Research; Center for Motor Neuron Biology and Disease, Columbia Stem Cell Initiative, Columbia University College of Physicians and Surgeons; New York New York USA
| | - Douglas M. Sproule
- Division of Pediatric Neurosciences, Department of Neurology; SMA Clinical Research Center, Columbia University Medical Center; Harkness Pavilion, HP-519, 180 Fort Washington Avenue New York New York 10032-3791 USA
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302
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Skotte NH, Southwell AL, Østergaard ME, Carroll JB, Warby SC, Doty CN, Petoukhov E, Vaid K, Kordasiewicz H, Watt AT, Freier SM, Hung G, Seth PP, Bennett CF, Swayze EE, Hayden MR. Allele-specific suppression of mutant huntingtin using antisense oligonucleotides: providing a therapeutic option for all Huntington disease patients. PLoS One 2014; 9:e107434. [PMID: 25207939 PMCID: PMC4160241 DOI: 10.1371/journal.pone.0107434] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 08/11/2014] [Indexed: 01/10/2023] Open
Abstract
Huntington disease (HD) is an inherited, fatal neurodegenerative disorder caused by a CAG repeat expansion in the huntingtin gene. The mutant protein causes neuronal dysfunction and degeneration resulting in motor dysfunction, cognitive decline, and psychiatric disturbances. Currently, there is no disease altering treatment, and symptomatic therapy has limited benefit. The pathogenesis of HD is complicated and multiple pathways are compromised. Addressing the problem at its genetic root by suppressing mutant huntingtin expression is a promising therapeutic strategy for HD. We have developed and evaluated antisense oligonucleotides (ASOs) targeting single nucleotide polymorphisms that are significantly enriched on HD alleles (HD-SNPs). We describe our structure-activity relationship studies for ASO design and find that adjusting the SNP position within the gap, chemical modifications of the wings, and shortening the unmodified gap are critical for potent, specific, and well tolerated silencing of mutant huntingtin. Finally, we show that using two distinct ASO drugs targeting the two allelic variants of an HD-SNP could provide a therapeutic option for all persons with HD; allele-specifically for roughly half, and non-specifically for the remainder.
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Affiliation(s)
- Niels H. Skotte
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Amber L. Southwell
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Jeffrey B. Carroll
- Behavioral Neuroscience Program, Department of Psychology, Western Washington University, Bellingham, Washington, United States of America
| | - Simon C. Warby
- Center for Advanced Research in Sleep Medicine, Department of Psychiatry, University of Montréal, Montréal, Quebec, Canada
| | - Crystal N. Doty
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Eugenia Petoukhov
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Kuljeet Vaid
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Andrew T. Watt
- ISIS Pharmaceuticals, Carlsbad, California, United States of America
| | - Susan M. Freier
- ISIS Pharmaceuticals, Carlsbad, California, United States of America
| | - Gene Hung
- ISIS Pharmaceuticals, Carlsbad, California, United States of America
| | - Punit P. Seth
- ISIS Pharmaceuticals, Carlsbad, California, United States of America
| | - C. Frank Bennett
- ISIS Pharmaceuticals, Carlsbad, California, United States of America
| | - Eric E. Swayze
- ISIS Pharmaceuticals, Carlsbad, California, United States of America
| | - Michael R. Hayden
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
- * E-mail:
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303
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Naryshkin NA, Weetall M, Dakka A, Narasimhan J, Zhao X, Feng Z, Ling KKY, Karp GM, Qi H, Woll MG, Chen G, Zhang N, Gabbeta V, Vazirani P, Bhattacharyya A, Furia B, Risher N, Sheedy J, Kong R, Ma J, Turpoff A, Lee CS, Zhang X, Moon YC, Trifillis P, Welch EM, Colacino JM, Babiak J, Almstead NG, Peltz SW, Eng LA, Chen KS, Mull JL, Lynes MS, Rubin LL, Fontoura P, Santarelli L, Haehnke D, McCarthy KD, Schmucki R, Ebeling M, Sivaramakrishnan M, Ko CP, Paushkin SV, Ratni H, Gerlach I, Ghosh A, Metzger F. Motor neuron disease. SMN2 splicing modifiers improve motor function and longevity in mice with spinal muscular atrophy. Science 2014; 345:688-93. [PMID: 25104390 DOI: 10.1126/science.1250127] [Citation(s) in RCA: 359] [Impact Index Per Article: 35.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Spinal muscular atrophy (SMA) is a genetic disease caused by mutation or deletion of the survival of motor neuron 1 (SMN1) gene. A paralogous gene in humans, SMN2, produces low, insufficient levels of functional SMN protein due to alternative splicing that truncates the transcript. The decreased levels of SMN protein lead to progressive neuromuscular degeneration and high rates of mortality. Through chemical screening and optimization, we identified orally available small molecules that shift the balance of SMN2 splicing toward the production of full-length SMN2 messenger RNA with high selectivity. Administration of these compounds to Δ7 mice, a model of severe SMA, led to an increase in SMN protein levels, improvement of motor function, and protection of the neuromuscular circuit. These compounds also extended the life span of the mice. Selective SMN2 splicing modifiers may have therapeutic potential for patients with SMA.
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Affiliation(s)
| | - Marla Weetall
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Amal Dakka
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Jana Narasimhan
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Xin Zhao
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Zhihua Feng
- Section of Neurobiology, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Karen K Y Ling
- Section of Neurobiology, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Gary M Karp
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Hongyan Qi
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Matthew G Woll
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Guangming Chen
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Nanjing Zhang
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | | | - Priya Vazirani
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | | | - Bansri Furia
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Nicole Risher
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Josephine Sheedy
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Ronald Kong
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Jiyuan Ma
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Anthony Turpoff
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Chang-Sun Lee
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Xiaoyan Zhang
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Young-Choon Moon
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | | | - Ellen M Welch
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Joseph M Colacino
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - John Babiak
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Neil G Almstead
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Stuart W Peltz
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA.
| | - Loren A Eng
- SMA Foundation, 888 Seventh Avenue, Suite 400, New York, NY 10019, USA
| | - Karen S Chen
- SMA Foundation, 888 Seventh Avenue, Suite 400, New York, NY 10019, USA
| | - Jesse L Mull
- Department of Stem Cell and Regenerative Biology and the Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA
| | - Maureen S Lynes
- Department of Stem Cell and Regenerative Biology and the Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA
| | - Lee L Rubin
- Department of Stem Cell and Regenerative Biology and the Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA
| | - Paulo Fontoura
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Luca Santarelli
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Daniel Haehnke
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | | | - Roland Schmucki
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Martin Ebeling
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Manaswini Sivaramakrishnan
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Chien-Ping Ko
- Section of Neurobiology, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Sergey V Paushkin
- SMA Foundation, 888 Seventh Avenue, Suite 400, New York, NY 10019, USA
| | - Hasane Ratni
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Irene Gerlach
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Anirvan Ghosh
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Friedrich Metzger
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Grenzacherstrasse 124, 4070 Basel, Switzerland.
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304
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Dugovic B, Wagner M, Leumann CJ. Structure/affinity studies in the bicyclo-DNA series: Synthesis and properties of oligonucleotides containing bc(en)-T and iso-tricyclo-T nucleosides. Beilstein J Org Chem 2014; 10:1840-7. [PMID: 25161745 PMCID: PMC4142851 DOI: 10.3762/bjoc.10.194] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 07/22/2014] [Indexed: 12/11/2022] Open
Abstract
We present the synthesis of the two novel nucleosides iso-tc-T and bc(en)-T, belonging to the bicyclo-/tricyclo-DNA molecular platform. In both modifications the torsion around C6'-C7' within the carbocyclic ring is planarized by either the presence of a C6'-C7' double bond or a cyclopropane ring. Structural analysis of these two nucleosides by X-ray analysis reveals a clear preference of torsion angle γ for the gauche orientation with the furanose ring in a near perfect 2'-endo conformation. Both modifications were incorporated into oligodeoxynucleotides and their thermal melting behavior with DNA and RNA as complements was assessed. We found that the iso-tc-T modification was significantly more destabilizing in duplex formation compared to the bc(en)-T modification. In addition, duplexes with complementary RNA were less stable as compared to duplexes with DNA as complement. A structure/affinity analysis, including the already known bc-T and tc-T modifications, does not lead to a clear correlation of the orientation of torsion angle γ with DNA or RNA affinity. There is, however, some correlation between furanose conformation (N- or S-type) and affinity in the sense that a preference for a 3'-endo like conformation is associated with a preference for RNA as complement. As a general rule it appears that T m data of single modifications with nucleosides of the bicyclo-/tricyclo-DNA platform within deoxyoligonucleotides are not predictive for the stability of fully modified oligonucleotides.
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Affiliation(s)
- Branislav Dugovic
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - Michael Wagner
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - Christian J Leumann
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
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305
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Mulcahy PJ, Iremonger K, Karyka E, Herranz-Martín S, Shum KT, Tam JKV, Azzouz M. Gene therapy: a promising approach to treating spinal muscular atrophy. Hum Gene Ther 2014; 25:575-86. [PMID: 24845847 DOI: 10.1089/hum.2013.186] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a severe autosomal recessive disease caused by a genetic defect in the survival motor neuron 1 (SMN1) gene, which encodes SMN, a protein widely expressed in all eukaryotic cells. Depletion of the SMN protein causes muscle weakness and progressive loss of movement in SMA patients. The field of gene therapy has made major advances over the past decade, and gene delivery to the central nervous system (CNS) by in vivo or ex vivo techniques is a rapidly emerging field in neuroscience. Despite Parkinson's disease, Alzheimer's disease, and amyotrophic lateral sclerosis being among the most common neurodegenerative diseases in humans and attractive targets for treatment development, their multifactorial origin and complicated genetics make them less amenable to gene therapy. Monogenic disorders resulting from modifications in a single gene, such as SMA, prove more favorable and have been at the fore of this evolution of potential gene therapies, and results to date have been promising at least. With the estimated number of monogenic diseases standing in the thousands, elucidating a therapeutic target for one could have major implications for many more. Recent progress has brought about the commercialization of the first gene therapies for diseases, such as pancreatitis in the form of Glybera, with the potential for other monogenic disease therapies to follow suit. While much research has been carried out, there are many limiting factors that can halt or impede translation of therapies from the bench to the clinic. This review will look at both recent advances and encountered impediments in terms of SMA and endeavor to highlight the promising results that may be applicable to various associated diseases and also discuss the potential to overcome present limitations.
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Affiliation(s)
- Pádraig J Mulcahy
- 1 Department of Neuroscience, Sheffield Institute for Translational Neuroscience, University of Sheffield , Sheffield S10 2HQ, United Kingdom
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306
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Abstract
Over the recent decade oligonucleotides have become an important new class of molecules, allowing therapeutic intervention through targets previously thought 'undruggable'. One of the new avenues opened up by oligonucleotide-based drugs was specific gene upregulation, which, historically, has been difficult to achieve using small-molecule drugs. This article will focus on patents covering this important development in the oligonucleotide field and highlight the different mechanisms through which the oligonucleotide-mediated gene upregulation can work, including inhibition of activity of natural antisense transcripts, interaction with promoter binding sites of noncoding regulatory RNAs, blocking of regulatory and/or miRNA binding sites in 3' UTRs, blocking splice inhibitor/enhancer sites or blocking interactions with polycomb repressive complex 2. Understanding the particular mechanism through which an oligonucleotide drug exerts its effects is highly important in drug development, as it determines the design of the drug molecule.
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307
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Disterer P, Kryczka A, Liu Y, Badi YE, Wong JJ, Owen JS, Khoo B. Development of therapeutic splice-switching oligonucleotides. Hum Gene Ther 2014; 25:587-98. [PMID: 24826963 DOI: 10.1089/hum.2013.234] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Synthetic splice-switching oligonucleotides (SSOs) target nuclear pre-mRNA molecules to change exon splicing and generate an alternative protein isoform. Clinical trials with two competitive SSO drugs are underway to treat Duchenne muscular dystrophy (DMD). Beyond DMD, many additional therapeutic applications are possible, with some in phase 1 clinical trials or advanced preclinical evaluation. Here, we present an overview of the central factors involved in developing therapeutic SSOs for the treatment of diseases. The selection of susceptible pre-mRNA target sequences, as well as the design and chemical modification of SSOs to increase SSO stability and effectiveness, are key initial considerations. Identification of effective SSO target sequences is still largely empirical and published guidelines are not a universal guarantee for success. Specifically, exon-targeted SSOs, which are successful in modifying dystrophin splicing, can be ineffective for splice-switching in other contexts. Chemical modifications, importantly, are associated with certain characteristic toxicities, which need to be addressed as target diseases require chronic treatment with SSOs. Moreover, SSO delivery in adequate quantities to the nucleus of target cells without toxicity can prove difficult. Last, the means by which these SSOs are administered needs to be acceptable to the patient. Engineering an efficient therapeutic SSO, therefore, necessarily entails a compromise between desirable qualities and effectiveness. Here, we describe how the application of optimal solutions may differ from case to case.
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Affiliation(s)
- Petra Disterer
- 1 Institute for Liver and Digestive Health, Division of Medicine, University College London , London, NW3 2PF, United Kingdom
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308
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Hunter G, Roche SL, Somers E, Fuller HR, Gillingwater TH. The influence of storage parameters on measurement of survival motor neuron (SMN) protein levels: implications for pre-clinical studies and clinical trials for spinal muscular atrophy. Neuromuscul Disord 2014; 24:973-7. [PMID: 25047670 DOI: 10.1016/j.nmd.2014.05.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 05/22/2014] [Accepted: 05/30/2014] [Indexed: 12/18/2022]
Abstract
Spinal muscular atrophy (SMA) is caused by low levels of survival motor neuron (SMN) protein. A growing number of potential therapeutic strategies for SMA are entering pre-clinical and clinical testing, including gene therapy and antisense oligonucleotide-based approaches. For many such studies SMN protein levels are used as one major readout of treatment efficacy, often necessitating comparisons between samples obtained at different times and/or using different protocols. Whether differences in tissue sampling strategies or storage parameters have an influence on measurable SMN levels remains to be determined. We assessed murine SMN protein immunoreactivity over time and under differing tissue storage conditions. SMN protein levels, measured using sensitive quantitative fluorescent western blotting, declined rapidly over a period of several days following sample collection, especially when protein was extracted immediately and stored at -20°C. Storage of samples at lower temperatures (-80°C), and as intact tissue, led to significantly better preservation of SMN immunoreactivity. However, considerable deterioration in measurable SMN levels occurred, even under optimal storage conditions. These issues need to be taken into consideration when designing and interpreting pre-clinical and clinical SMA studies where SMN protein levels are being measured.
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Affiliation(s)
- Gillian Hunter
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK; Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Sarah L Roche
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK; Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Eilidh Somers
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK; Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Heidi R Fuller
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, UK
| | - Thomas H Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK; Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK; Institute for Science and Technology in Medicine, Keele University, Keele, UK.
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309
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Tawil R, van der Maarel SM, Tapscott SJ. Facioscapulohumeral dystrophy: the path to consensus on pathophysiology. Skelet Muscle 2014; 4:12. [PMID: 24940479 PMCID: PMC4060068 DOI: 10.1186/2044-5040-4-12] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 05/13/2014] [Indexed: 01/07/2023] Open
Abstract
Although the pathophysiology of facioscapulohumeral dystrophy (FSHD) has been controversial over the last decades, progress in recent years has led to a model that incorporates these decades of findings and is gaining general acceptance in the FSHD research community. Here we review how the contributions from many labs over many years led to an understanding of a fundamentally new mechanism of human disease. FSHD is caused by inefficient repeat-mediated epigenetic repression of the D4Z4 macrosatellite repeat array on chromosome 4, resulting in the variegated expression of the DUX4 retrogene, encoding a double-homeobox transcription factor, in skeletal muscle. Normally expressed in the testis and epigenetically repressed in somatic tissues, DUX4 expression in skeletal muscle induces expression of many germline, stem cell, and other genes that might account for the pathophysiology of FSHD. Although some disagreements regarding the details of mechanisms remain in the field, the coalescing agreement on a central model of pathophysiology represents a pivot-point in FSHD research, transitioning the field from discovery-oriented studies to translational studies aimed at developing therapies based on a sound model of disease pathophysiology.
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Affiliation(s)
- Rabi Tawil
- Department of Neurology, University of Rochester, Rochester, NY 14642, USA
- Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA
| | - Silvère M van der Maarel
- Department of Human Genetics, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
- Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA
| | - Stephen J Tapscott
- Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
- Department of Neurology, University of Washington, Seattle, WA 98105, USA
- Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA
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310
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311
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Rigo F, Chun SJ, Norris DA, Hung G, Lee S, Matson J, Fey RA, Gaus H, Hua Y, Grundy JS, Krainer AR, Henry SP, Bennett CF. Pharmacology of a central nervous system delivered 2'-O-methoxyethyl-modified survival of motor neuron splicing oligonucleotide in mice and nonhuman primates. J Pharmacol Exp Ther 2014; 350:46-55. [PMID: 24784568 DOI: 10.1124/jpet.113.212407] [Citation(s) in RCA: 206] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a debilitating neuromuscular disease caused by the loss of survival of motor neuron (SMN) protein. Previously, we demonstrated that ISIS 396443, an antisense oligonucleotide (ASO) targeted to the SMN2 pre-mRNA, is a potent inducer of SMN2 exon 7 inclusion and SMN protein expression, and improves function and survival of mild and severe SMA mouse models. Here, we demonstrate that ISIS 396443 is the most potent ASO in central nervous system (CNS) tissues of adult mice, compared with several other chemically modified ASOs. We evaluated methods of ISIS 396443 delivery to the CNS and characterized its pharmacokinetics and pharmacodynamics in rodents and nonhuman primates (NHPs). Intracerebroventricular bolus injection is a more efficient method of delivering ISIS 396443 to the CNS of rodents, compared with i.c.v. infusion. For both methods of delivery, the duration of ISIS 396443-mediated SMN2 splicing correction is long lasting, with maximal effects still observed 6 months after treatment discontinuation. Administration of ISIS 396443 to the CNS of NHPs by a single intrathecal bolus injection results in widespread distribution throughout the spinal cord. Based upon these preclinical studies, we have advanced ISIS 396443 into clinical development.
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Affiliation(s)
- Frank Rigo
- Isis Pharmaceuticals, Carlsbad, California (F.R., S.J.C., D.A.N., G.H., S.L., J.M., R.A.F., H.G., J.S.G., S.P.H., C.F.B.); and Cold Spring Harbor Laboratory, Cold Spring Harbor, New York (Y.H., A.R.K.)
| | - Seung J Chun
- Isis Pharmaceuticals, Carlsbad, California (F.R., S.J.C., D.A.N., G.H., S.L., J.M., R.A.F., H.G., J.S.G., S.P.H., C.F.B.); and Cold Spring Harbor Laboratory, Cold Spring Harbor, New York (Y.H., A.R.K.)
| | - Daniel A Norris
- Isis Pharmaceuticals, Carlsbad, California (F.R., S.J.C., D.A.N., G.H., S.L., J.M., R.A.F., H.G., J.S.G., S.P.H., C.F.B.); and Cold Spring Harbor Laboratory, Cold Spring Harbor, New York (Y.H., A.R.K.)
| | - Gene Hung
- Isis Pharmaceuticals, Carlsbad, California (F.R., S.J.C., D.A.N., G.H., S.L., J.M., R.A.F., H.G., J.S.G., S.P.H., C.F.B.); and Cold Spring Harbor Laboratory, Cold Spring Harbor, New York (Y.H., A.R.K.)
| | - Sam Lee
- Isis Pharmaceuticals, Carlsbad, California (F.R., S.J.C., D.A.N., G.H., S.L., J.M., R.A.F., H.G., J.S.G., S.P.H., C.F.B.); and Cold Spring Harbor Laboratory, Cold Spring Harbor, New York (Y.H., A.R.K.)
| | - John Matson
- Isis Pharmaceuticals, Carlsbad, California (F.R., S.J.C., D.A.N., G.H., S.L., J.M., R.A.F., H.G., J.S.G., S.P.H., C.F.B.); and Cold Spring Harbor Laboratory, Cold Spring Harbor, New York (Y.H., A.R.K.)
| | - Robert A Fey
- Isis Pharmaceuticals, Carlsbad, California (F.R., S.J.C., D.A.N., G.H., S.L., J.M., R.A.F., H.G., J.S.G., S.P.H., C.F.B.); and Cold Spring Harbor Laboratory, Cold Spring Harbor, New York (Y.H., A.R.K.)
| | - Hans Gaus
- Isis Pharmaceuticals, Carlsbad, California (F.R., S.J.C., D.A.N., G.H., S.L., J.M., R.A.F., H.G., J.S.G., S.P.H., C.F.B.); and Cold Spring Harbor Laboratory, Cold Spring Harbor, New York (Y.H., A.R.K.)
| | - Yimin Hua
- Isis Pharmaceuticals, Carlsbad, California (F.R., S.J.C., D.A.N., G.H., S.L., J.M., R.A.F., H.G., J.S.G., S.P.H., C.F.B.); and Cold Spring Harbor Laboratory, Cold Spring Harbor, New York (Y.H., A.R.K.)
| | - John S Grundy
- Isis Pharmaceuticals, Carlsbad, California (F.R., S.J.C., D.A.N., G.H., S.L., J.M., R.A.F., H.G., J.S.G., S.P.H., C.F.B.); and Cold Spring Harbor Laboratory, Cold Spring Harbor, New York (Y.H., A.R.K.)
| | - Adrian R Krainer
- Isis Pharmaceuticals, Carlsbad, California (F.R., S.J.C., D.A.N., G.H., S.L., J.M., R.A.F., H.G., J.S.G., S.P.H., C.F.B.); and Cold Spring Harbor Laboratory, Cold Spring Harbor, New York (Y.H., A.R.K.)
| | - Scott P Henry
- Isis Pharmaceuticals, Carlsbad, California (F.R., S.J.C., D.A.N., G.H., S.L., J.M., R.A.F., H.G., J.S.G., S.P.H., C.F.B.); and Cold Spring Harbor Laboratory, Cold Spring Harbor, New York (Y.H., A.R.K.)
| | - C Frank Bennett
- Isis Pharmaceuticals, Carlsbad, California (F.R., S.J.C., D.A.N., G.H., S.L., J.M., R.A.F., H.G., J.S.G., S.P.H., C.F.B.); and Cold Spring Harbor Laboratory, Cold Spring Harbor, New York (Y.H., A.R.K.)
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312
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Osman EY, Miller MR, Robbins KL, Lombardi AM, Atkinson AK, Brehm AJ, Lorson CL. Morpholino antisense oligonucleotides targeting intronic repressor Element1 improve phenotype in SMA mouse models. Hum Mol Genet 2014; 23:4832-45. [PMID: 24781211 DOI: 10.1093/hmg/ddu198] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disease caused by the loss of Survival Motor Neuron-1 (SMN1). In all SMA patients, a nearly identical copy gene called SMN2 is present, which produces low levels of functional protein owing to an alternative splicing event. To prevent exon-skipping, we have targeted an intronic repressor, Element1 (E1), located upstream of SMN2 exon 7 using Morpholino-based antisense oligonucleotides (E1(MO)-ASOs). A single intracerebroventricular injection in the relatively severe mouse model of SMA (SMNΔ7 mouse model) elicited a robust induction of SMN protein, and mean life span was extended from an average survival of 13 to 54 days following a single dose, consistent with large weight gains and a correction of the neuronal pathology. Additionally, E1(MO)-ASO treatment in an intermediate SMA mouse (SMN(RT) mouse model) significantly extended life span by ∼700% and weight gain was comparable with the unaffected animals. While a number of experimental therapeutics have targeted the ISS-N1 element of SMN2 pre-mRNA, the development of E1 ASOs provides a new molecular target for SMA therapeutics that dramatically extends survival in two important pre-clinical models of disease.
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Affiliation(s)
- Erkan Y Osman
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO 65211, USA, Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Madeline R Miller
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA, Genetics Area Program, Christopher S. Bond Life Sciences Center Room 403, University of Missouri, Columbia, MO 65211, USA and
| | - Kate L Robbins
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Abby M Lombardi
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Arleigh K Atkinson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Amanda J Brehm
- College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Christian L Lorson
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO 65211, USA, Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA, Genetics Area Program, Christopher S. Bond Life Sciences Center Room 403, University of Missouri, Columbia, MO 65211, USA and
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313
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Passini MA, Bu J, Richards AM, Treleaven CM, Sullivan JA, O'Riordan CR, Scaria A, Kells AP, Samaranch L, San Sebastian W, Federici T, Fiandaca MS, Boulis NM, Bankiewicz KS, Shihabuddin LS, Cheng SH. Translational fidelity of intrathecal delivery of self-complementary AAV9-survival motor neuron 1 for spinal muscular atrophy. Hum Gene Ther 2014; 25:619-30. [PMID: 24617515 DOI: 10.1089/hum.2014.011] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disease caused by mutations in survival motor neuron 1 (SMN1). Previously, we showed that central nervous system (CNS) delivery of an adeno-associated viral (AAV) vector encoding SMN1 produced significant improvements in survival in a mouse model of SMA. Here, we performed a dose-response study in SMA mice to determine the levels of SMN in the spinal cord necessary for efficacy, and measured the efficiency of motor neuron transduction in the spinal cord after intrathecal delivery in pigs and nonhuman primates (NHPs). CNS injections of 5e10, 1e10, and 1e9 genome copies (gc) of self-complementary AAV9 (scAAV9)-hSMN1 into SMA mice extended their survival from 17 to 153, 70, and 18 days, respectively. Spinal cords treated with 5e10, 1e10, and 1e9 gc showed that 70-170%, 30-100%, and 10-20% of wild-type levels of SMN were attained, respectively. Furthermore, detectable SMN expression in a minimum of 30% motor neurons correlated with efficacy. A comprehensive analysis showed that intrathecal delivery of 2.5e13 gc of scAAV9-GFP transduced 25-75% of the spinal cord motor neurons in NHPs. Thus, the extent of gene expression in motor neurons necessary to confer efficacy in SMA mice could be obtained in large-animal models, justifying the continual development of gene therapy for SMA.
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Affiliation(s)
- Marco A Passini
- 1 Rare Diseases Science, Genzyme, a Sanofi Company , Framingham, MA 01701
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314
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Oligonucleotide-based therapy for neurodegenerative diseases. Brain Res 2014; 1584:116-28. [PMID: 24727531 DOI: 10.1016/j.brainres.2014.04.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 04/04/2014] [Accepted: 04/05/2014] [Indexed: 12/12/2022]
Abstract
Molecular genetics insight into the pathogenesis of several neurodegenerative diseases, such as Alzheimer׳s disease, Parkinson׳s disease, Huntington׳s disease and amyotrophic lateral sclerosis, encourages direct interference with the activity of neurotoxic genes or the molecular activation of neuroprotective pathways. Oligonucleotide-based therapies are recently emerging as an efficient strategy for drug development and these can be employed as new treatments of neurodegenerative states. Here we review advances in this field in recent years which suggest an encouraging assessment that oligonucleotide technologies for targeting of RNAs will enable the development of new therapies and will contribute to preservation of brain integrity.
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315
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Robbins KL, Glascock JJ, Osman EY, Miller MR, Lorson CL. Defining the therapeutic window in a severe animal model of spinal muscular atrophy. Hum Mol Genet 2014; 23:4559-68. [PMID: 24722206 DOI: 10.1093/hmg/ddu169] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disease caused by the loss of a single gene, Survival Motor Neuron-1 (SMN1). Administration of a self-complementary Adeno-Associated Virus vector expressing full-length SMN cDNA (scAAV-SMN) has proven an effective means to rescue the SMA phenotype in SMA mice, either by intravenous (IV) or intracerebroventricular (ICV) administration at very early time points. We have recently shown that ICV delivery of scAAV9-SMN is more effective than a similar dose of vector administered via an IV injection, thereby providing an important mechanism to examine a timeline for rescuing the disease and determining the therapeutic window in a severe model of SMA. In this report, we utilized a relatively severe mouse model of SMA, SMNΔ7. Animals were injected with scAAV9-SMN vector via ICV injection on a single day, from P2 through P8. At each delivery point from P2 through P8, scAAV9-SMN decreased disease severity. A near complete rescue was obtained following P2 injection while a P8 injection produced a ∼ 40% extension in survival. Analysis of the underlying neuromuscular junction (NMJ) pathology revealed that late-stage delivery of the vector failed to provide protection from NMJ defects despite robust SMN expression in the central nervous system. While our study demonstrates that a maximal benefit is obtained when treatment is delivered during pre-symptomatic stages, significant therapeutic benefit can still be achieved after the onset of disease symptoms.
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Affiliation(s)
- Kate L Robbins
- Department of Veterinary Pathobiology, Christopher S. Bond Life Sciences Center
| | - Jacqueline J Glascock
- Department of Veterinary Pathobiology, Christopher S. Bond Life Sciences Center, Department of Molecular Microbiology and Immunology, University of Missouri School of Medicine and
| | - Erkan Y Osman
- Department of Veterinary Pathobiology, Christopher S. Bond Life Sciences Center, Department of Molecular Microbiology and Immunology, University of Missouri School of Medicine and
| | - Madeline R Miller
- Genetics Area Program, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Christian L Lorson
- Department of Veterinary Pathobiology, Christopher S. Bond Life Sciences Center, Department of Molecular Microbiology and Immunology, University of Missouri School of Medicine and
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316
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Seth PP, Swayze EE. Unnatural Nucleoside Analogs for Antisense Therapy. METHODS AND PRINCIPLES IN MEDICINAL CHEMISTRY 2014. [DOI: 10.1002/9783527676545.ch12] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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317
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Touznik A, Lee JJA, Yokota T. New developments in exon skipping and splice modulation therapies for neuromuscular diseases. Expert Opin Biol Ther 2014; 14:809-19. [PMID: 24620745 DOI: 10.1517/14712598.2014.896335] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
INTRODUCTION Antisense oligonucleotide (AON) therapy is a form of treatment for genetic or infectious diseases using small, synthetic DNA-like molecules called AONs. Recent advances in the development of AONs that show improved stability and increased sequence specificity have led to clinical trials for several neuromuscular diseases. Impressive preclinical and clinical data are published regarding the usage of AONs in exon-skipping and splice modulation strategies to increase dystrophin production in Duchenne muscular dystrophy (DMD) and survival of motor neuron (SMN) production in spinal muscular atrophy (SMA). AREAS COVERED In this review, we focus on the current progress and challenges of exon-skipping and splice modulation therapies. In addition, we discuss the recent failure of the Phase III clinical trials of exon 51 skipping (drisapersen) for DMD. EXPERT OPINION The main approach of AON therapy in DMD and SMA is to rescue ('knock up' or increase) target proteins through exon skipping or exon inclusion; conversely, most conventional antisense drugs are designed to knock down (inhibit) the target. Encouraging preclinical data using this 'knock up' approach are also reported to rescue dysferlinopathies, including limb-girdle muscular dystrophy type 2B, Miyoshi myopathy, distal myopathy with anterior tibial onset and Fukuyama congenital muscular dystrophy.
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Affiliation(s)
- Aleksander Touznik
- University of Alberta, Faculty of Medicine and Dentistry, Department of Medical Genetics , Edmonton, Alberta , Canada
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318
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Iyer CC, McGovern VL, Wise DO, Glass DJ, Burghes AHM. Deletion of atrophy enhancing genes fails to ameliorate the phenotype in a mouse model of spinal muscular atrophy. Neuromuscul Disord 2014; 24:436-44. [PMID: 24656734 DOI: 10.1016/j.nmd.2014.02.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 01/16/2014] [Accepted: 02/11/2014] [Indexed: 11/25/2022]
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive disease causing degeneration of lower motor neurons and muscle atrophy. One therapeutic avenue for SMA is targeting signaling pathways in muscle to ameliorate atrophy. Muscle Atrophy F-box, MAFbx, and Muscle RING Finger 1, MuRF1, are muscle-specific ubiquitin ligases upregulated in skeletal and cardiac muscle during atrophy. Homozygous knock-out of MAFbx or MuRF1 causes muscle sparing in adult mice subjected to atrophy by denervation. We wished to determine whether blockage of the major muscle atrophy pathways by deletion of MAFbx or MuRF1 in a mouse model of SMA would improve the phenotype. Deletion of MAFbx in the Δ7 SMA mouse model had no effect on the weight and the survival of the mice while deletion of MuRF1 was deleterious. MAFbx(-/-)-SMA mice showed a significant alteration in fiber size distribution tending towards larger fibers. In skeletal and cardiac tissue MAFbx and MuRF1 transcripts were upregulated whereas MuRF2 and MuRF3 levels were unchanged in Δ7 SMA mice. We conclude that deletion of the muscle ubiquitin ligases does not improve the phenotype of a Δ7 SMA mouse. Furthermore, it seems unlikely that the beneficial effect of HDAC inhibitors is mediated through inhibition of MAFbx and MuRF1.
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Affiliation(s)
- Chitra C Iyer
- Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Vicki L McGovern
- Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Dawnne O Wise
- Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH, USA
| | - David J Glass
- Novartis Institutes for Biomedical Research, Cambridge, MA, USA
| | - Arthur H M Burghes
- Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH, USA; Department of Neurology, The Ohio State University, Columbus, OH, USA; Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA.
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319
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Zanetta C, Riboldi G, Nizzardo M, Simone C, Faravelli I, Bresolin N, Comi GP, Corti S. Molecular, genetic and stem cell-mediated therapeutic strategies for spinal muscular atrophy (SMA). J Cell Mol Med 2014; 18:187-96. [PMID: 24400925 PMCID: PMC3930406 DOI: 10.1111/jcmm.12224] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Accepted: 12/03/2013] [Indexed: 12/13/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive motor neuron disease. It is the first genetic cause of infant mortality. It is caused by mutations in the survival motor neuron 1 (SMN1) gene, leading to the reduction of SMN protein. The most striking component is the loss of alpha motor neurons in the ventral horn of the spinal cord, resulting in progressive paralysis and eventually premature death. There is no current treatment other than supportive care, although the past decade has seen a striking advancement in understanding of both SMA genetics and molecular mechanisms. A variety of disease modifying interventions are rapidly bridging the translational gap from the laboratory to clinical trials. In this review, we would like to outline the most interesting therapeutic strategies that are currently developing, which are represented by molecular, gene and stem cell-mediated approaches for the treatment of SMA.
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Affiliation(s)
- Chiara Zanetta
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore PoliclinicoMilan, Italy
| | - Giulietta Riboldi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore PoliclinicoMilan, Italy
| | - Monica Nizzardo
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore PoliclinicoMilan, Italy
| | - Chiara Simone
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore PoliclinicoMilan, Italy
| | - Irene Faravelli
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore PoliclinicoMilan, Italy
| | - Nereo Bresolin
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore PoliclinicoMilan, Italy
| | - Giacomo P Comi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore PoliclinicoMilan, Italy
| | - Stefania Corti
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore PoliclinicoMilan, Italy
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320
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Sterne-Weiler T, Sanford JR. Exon identity crisis: disease-causing mutations that disrupt the splicing code. Genome Biol 2014; 15:201. [PMID: 24456648 PMCID: PMC4053859 DOI: 10.1186/gb4150] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Cis-acting RNA elements control the accurate expression of human multi-exon protein coding genes. Single nucleotide variants altering the fidelity of this regulatory code and, consequently, pre-mRNA splicing are expected to contribute to the etiology of numerous human diseases.
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321
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Abstract
Alternative splicing plays a prevalent role in generating functionally diversified proteomes from genomes with a more limited repertoire of protein-coding genes. Alternative splicing is frequently regulated with cell type or developmental specificity and in response to signaling pathways, and its mis-regulation can lead to disease. Co-regulated programs of alternative splicing involve interplay between a host of cis-acting transcript features and trans-acting RNA-binding proteins. Here, we review the current state of understanding of the logic and mechanism of regulated alternative splicing and indicate how this understanding can be exploited to manipulate splicing for therapeutic purposes.
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Affiliation(s)
- Miguel B Coelho
- Department of Biochemistry, University of Cambridge, Cambridge, UK
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322
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Taking a risk: a therapeutic focus on ataxin-2 in amyotrophic lateral sclerosis? Trends Mol Med 2014; 20:25-35. [DOI: 10.1016/j.molmed.2013.09.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 09/03/2013] [Accepted: 09/17/2013] [Indexed: 12/12/2022]
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323
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Anticancer gene transfer for cancer gene therapy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 818:255-80. [PMID: 25001541 DOI: 10.1007/978-1-4471-6458-6_13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Gene therapy vectors are among the treatments currently used to treat malignant tumors. Gene therapy vectors use a specific therapeutic transgene that causes death in cancer cells. In early attempts at gene therapy, therapeutic transgenes were driven by non-specific vectors which induced toxicity to normal cells in addition to the cancer cells. Recently, novel cancer specific viral vectors have been developed that target cancer cells leaving normal cells unharmed. Here we review such cancer specific gene therapy systems currently used in the treatment of cancer and discuss the major challenges and future directions in this field.
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324
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Investigation of a recombinant SMN protein delivery system to treat spinal muscular atrophy. Transl Neurosci 2014. [DOI: 10.2478/s13380-014-0201-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractSpinal muscular atrophy (SMA), the most common genetic cause of infant death, is a neurodegenerative disorder affecting motor neurons. SMA results from a loss in full-length survival of motor neuron (SMN) protein due to deletions/mutations in the SMN1 gene. In this study, we assessed the ability of cell-penetrating peptides (CPP) to deliver recombinant SMN protein to cultured neurons as a prelude for a potential therapeutic to treat SMA. Firstly, we confirmed that E. coli produced recombinant GFP protein fused to TAT (YGRKKRRQRRR; TAT-GFP) transduced rat cortical neurons in a concentration dependent manner. However, due to low yields of recombinant TATSMN protein obtainable from E. coli, we investigated the potential of a modified TAT (TATκ: YARKAARQARA) or R9 (RRRRRRRRR) peptide downstream of the fibronectin (FIB) secretory signal peptide to generate recombinant CPP-fused SMN protein. While U251 cells transduced with an adenoviral vector expressing CMV-FIB-TATκ-SMN secreted recombinant TATκ-SMN protein, we did not detect TATκ-SMN protein transduction of cortical neurons. Further, purified TATκ-SMN was unable to transduce SH-SY5Y cells, nor block apoptosis following LY294002 treatment of these cells. Our findings indicate that TATκ is not a suitable CPP to deliver SMN protein to neurons. Nonetheless, we have developed a novel method to generate full-length recombinant SMN protein using a mammalian expression system, which can be used to explore the application of other CPPs to deliver SMN protein as a treatment for SMA.
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325
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Porensky PN, Burghes AHM. Antisense oligonucleotides for the treatment of spinal muscular atrophy. Hum Gene Ther 2013; 24:489-98. [PMID: 23544870 DOI: 10.1089/hum.2012.225] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive disease affecting ∼1 in 10,000 live births. The most striking component is the loss of α-motor neurons in the ventral horn of the spinal cord, resulting in progressive paralysis and eventually premature death. There is no current treatment paradigm other than supportive care, though the past 15 years has seen a striking advancement in understanding of both SMA genetics and molecular mechanisms. A variety of disease-modifying interventions are rapidly bridging the translational gap from the laboratory to clinical trials, including the application of antisense oligonucleotide (ASO) therapy for the correction of aberrant RNA splicing characteristic of SMA. Survival motor neuron (SMN) is a ubiquitously expressed 38-kD protein. Humans have two genes that produce SMN, SMN1 and SMN2, the former of which is deleted or nonfunctional in the majority of patients with SMA. These two genes are nearly identical with one exception, a C to T transition (C6T) within exon 7 of SMN2. C6T disrupts a modulator of splicing, leading to the exclusion of exon 7 from ∼90% of the mRNA transcript. The resultant truncated Δ7SMN protein does not oligomerize efficiently and is rapidly degraded. SMA can therefore be considered a disease of too little SMN protein. A number of cis-acting splice modifiers have been identified in the region of exon 7, the steric block of which enhances the retention of the exon and a resultant full-length mRNA sequence. ASOs targeted to these splice motifs have shown impressive phenotype rescue in multiple SMA mouse models.
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Affiliation(s)
- Paul N Porensky
- Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH 43210, USA
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326
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Zanetta C, Nizzardo M, Simone C, Monguzzi E, Bresolin N, Comi GP, Corti S. Molecular therapeutic strategies for spinal muscular atrophies: current and future clinical trials. Clin Ther 2013; 36:128-40. [PMID: 24360800 DOI: 10.1016/j.clinthera.2013.11.006] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 10/28/2013] [Accepted: 11/22/2013] [Indexed: 11/17/2022]
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is an autosomal recessive motor neuron disease caused by mutations in the survival motor neuron gene (SMN1) and the leading genetic cause of infant mortality. Currently, there is no effective treatment other than supportive care. OBJECTIVE This article provides a general overview of the main aspects that need to be taken into account to design a more efficient clinical trial and to summarize the most promising molecular trials that are currently in development or are being planned for the treatment of SMA. METHODS A systematic review of the literature was performed, identifying key clinical trials involving novel molecular therapies in SMA. In addition, abstracts presented at the meetings of the Families of Spinal Muscular Atrophy were searched and the Families of Spinal Muscular Atrophy Web site was carefully analyzed. Finally, a selection of SMA clinical trials registered at clinical-trials.gov has been included in the article. RESULTS The past decade has seen a marked advancement in the understanding of both SMA genetics and molecular mechanisms. New molecules targeting SMN have shown promise in preclinical studies, and various clinical trials have started to test the drugs that were discovered through basic research. CONCLUSIONS Both preclinical and early clinical trial results involving novel molecular therapies suggest that the clinical care paradigm in SMA will soon change.
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Affiliation(s)
- Chiara Zanetta
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Monica Nizzardo
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Chiara Simone
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Erika Monguzzi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Nereo Bresolin
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Giacomo P Comi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Stefania Corti
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
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327
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Arnold WD, Burghes AHM. Spinal muscular atrophy: development and implementation of potential treatments. Ann Neurol 2013; 74:348-62. [PMID: 23939659 DOI: 10.1002/ana.23995] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 07/13/2013] [Accepted: 08/01/2013] [Indexed: 12/13/2022]
Abstract
In neurodegenerative disorders, effective treatments are urgently needed, along with methods to determine whether treatment worked. In this review, we discuss the rapid progress in the understanding of recessive proximal spinal muscular atrophy and how this is leading to exciting potential treatments of the disease. Spinal muscular atrophy is caused by loss of the survival motor neuron 1 (SMN1) gene and reduced levels of SMN protein. The critical downstream targets of SMN deficiency that result in motor neuron loss are not known. However, increasing SMN levels has a marked impact in mouse models, and these therapeutics are rapidly moving toward clinical trials. Promising preclinical therapies, the varying degree of impact on the mouse models, and potential measures of treatment effect are reviewed. One key issue discussed is the variable outcome of increasing SMN at different stages of disease progression.
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Affiliation(s)
- W David Arnold
- Neuromuscular Division, Department of Neurology, Wexner Medical Center, the Ohio State University, Columbus, OH; Department of Physical Medicine and Rehabilitation, Wexner Medical Center, the Ohio State University, Columbus, OH
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328
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Dual masking of specific negative splicing regulatory elements resulted in maximal exon 7 inclusion of SMN2 gene. Mol Ther 2013; 22:854-61. [PMID: 24317636 DOI: 10.1038/mt.2013.276] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 12/01/2013] [Indexed: 12/18/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a fatal autosomal recessive disease caused by survival motor neuron (SMN) protein insufficiency due to SMN1 mutations. Boosting SMN2 expression is a potential therapy for SMA. SMN2 has identical coding sequence as SMN1 except for a silent C-to-T transition at the 6th nucleotide of exon 7, converting a splicing enhancer to a silencer motif. Consequently, most SMN2 transcripts lack exon 7. More than ten putative splicing regulatory elements (SREs) were reported to regulate exon 7 splicing. To investigate the relative strength of each negative SRE in inhibiting exon 7 inclusion, antisense oligonucleotides (AONs) were used to mask each element, and the fold increase of full-length SMN transcripts containing exon 7 were compared. The most potent negative SREs are at intron 7 (in descending order): ISS-N1, 3' splice site of exon 8 (ex8 3'ss) and ISS+100. Dual-targeting AONs were subsequently used to mask two nonadjacent SREs simultaneously. Notably, masking of both ISS-N1 and ex8 3'ss induced the highest fold increase of full-length SMN transcripts and proteins. Therefore, efforts should be directed towards the two elements simultaneously for the development of optimal AONs for SMA therapy.
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Abstract
PURPOSE OF REVIEW Spinal muscular atrophy (SMA) is a pediatric neuromuscular condition characterized by progressive proximal muscle weakness. It is one of the most common genetic causes of infant mortality across different races and is caused by mutation of the survival of motor neuron 1 (SMN1) gene on chromosome 5q13. RECENT FINDINGS To date, there have been many therapeutics developments for SMA targeting various potential pathways such as increasing SMN gene expression, enhancing SMN2 exon 7 inclusion, neuroprotection, cell replacement, and gene therapy. SUMMARY Although SMA remains an incurable disease to date, recent advances in the field of basic and translational research have enhanced our understanding of the pathogenesis of the disease and opened new possibilities for therapeutic intervention. This article reviews and highlights past and current translational research on SMA therapeutics.
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Affiliation(s)
- Priyamvada Singh
- aDepartment of Neurology, Boston Children's Hospital and Harvard Medical School, Boston bSaint Vincent Hospital, Worcester, USA *Priyamvada Singh and Wendy K.M. Liew contributed equally to the writing of this article
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330
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Järver P, O'Donovan L, Gait MJ. A chemical view of oligonucleotides for exon skipping and related drug applications. Nucleic Acid Ther 2013; 24:37-47. [PMID: 24171481 DOI: 10.1089/nat.2013.0454] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Affiliation(s)
- Peter Järver
- Medical Research Council , Laboratory of Molecular Biology, Cambridge, United Kingdom
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331
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Abstract
Tau, a microtubule-associated protein, is implicated in the pathogenesis of Alzheimer's Disease (AD) in regard to both neurofibrillary tangle formation and neuronal network hyperexcitability. The genetic ablation of tau substantially reduces hyperexcitability in AD mouse lines, induced seizure models, and genetic in vivo models of epilepsy. These data demonstrate that tau is an important regulator of network excitability. However, developmental compensation in the genetic tau knock-out line may account for the protective effect against seizures. To test the efficacy of a tau reducing therapy for disorders with a detrimental hyperexcitability profile in adult animals, we identified antisense oligonucleotides that selectively decrease endogenous tau expression throughout the entire mouse CNS--brain and spinal cord tissue, interstitial fluid, and CSF--while having no effect on baseline motor or cognitive behavior. In two chemically induced seizure models, mice with reduced tau protein had less severe seizures than control mice. Total tau protein levels and seizure severity were highly correlated, such that those mice with the most severe seizures also had the highest levels of tau. Our results demonstrate that endogenous tau is integral for regulating neuronal hyperexcitability in adult animals and suggest that an antisense oligonucleotide reduction of tau could benefit those with epilepsy and perhaps other disorders associated with tau-mediated neuronal hyperexcitability.
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332
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Van Meerbeke JP, Gibbs RM, Plasterer HL, Miao W, Feng Z, Lin MY, Rucki AA, Wee CD, Xia B, Sharma S, Jacques V, Li DK, Pellizzoni L, Rusche JR, Ko CP, Sumner CJ. The DcpS inhibitor RG3039 improves motor function in SMA mice. Hum Mol Genet 2013; 22:4074-83. [PMID: 23727836 PMCID: PMC3781637 DOI: 10.1093/hmg/ddt257] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 05/07/2013] [Accepted: 05/28/2013] [Indexed: 11/14/2022] Open
Abstract
Spinal muscular atrophy (SMA) is caused by mutations of the survival motor neuron 1 (SMN1) gene, retention of the survival motor neuron 2 (SMN2) gene and insufficient expression of full-length survival motor neuron (SMN) protein. Quinazolines increase SMN2 promoter activity and inhibit the ribonucleic acid scavenger enzyme DcpS. The quinazoline derivative RG3039 has advanced to early phase clinical trials. In preparation for efficacy studies in SMA patients, we investigated the effects of RG3039 in severe SMA mice. Here, we show that RG3039 distributed to central nervous system tissues where it robustly inhibited DcpS enzyme activity, but minimally activated SMN expression or the assembly of small nuclear ribonucleoproteins. Nonetheless, treated SMA mice showed a dose-dependent increase in survival, weight and motor function. This was associated with improved motor neuron somal and neuromuscular junction synaptic innervation and function and increased muscle size. RG3039 also enhanced survival of conditional SMA mice in which SMN had been genetically restored to motor neurons. As this systemically delivered drug may have therapeutic benefits that extend beyond motor neurons, it could act additively with SMN-restoring therapies delivered directly to the central nervous system such as antisense oligonucleotides or gene therapy.
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Affiliation(s)
| | - Rebecca M. Gibbs
- Section of Neurobiology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | | | | | - Zhihua Feng
- Section of Neurobiology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Ming-Yi Lin
- Section of Neurobiology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | | | | | - Bing Xia
- Repligen Corporation, Watham, MA, USA
| | | | | | - Darrick K. Li
- Department of Pathology and Cell Biology and
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, USA
| | - Livio Pellizzoni
- Department of Pathology and Cell Biology and
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, USA
| | | | - Chien-Ping Ko
- Section of Neurobiology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Charlotte J. Sumner
- Department of Neurology and
- Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA
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333
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Tiziano FD, Melki J, Simard LR. Solving the puzzle of spinal muscular atrophy: what are the missing pieces? Am J Med Genet A 2013; 161A:2836-45. [PMID: 24124019 DOI: 10.1002/ajmg.a.36251] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Accepted: 08/30/2013] [Indexed: 12/13/2022]
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive, lower motor neuron disease. Clinical heterogeneity is pervasive: three infantile (type I-III) and one adult-onset (type IV) forms are recognized. Type I SMA is the most common genetic cause of death in infancy and accounts for about 50% of all patients with SMA. Most forms of SMA are caused by mutations of the survival motor neuron (SMN1) gene. A second gene that is 99% identical to SMN1 (SMN2) is located in the same region. The only functionally relevant difference between the two genes identified to date is a C → T transition in exon 7 of SMN2, which determines an alternative spliced isoform that predominantly excludes exon 7. Thus, SMN2 genes do not produce sufficient full length SMN protein to prevent the onset of the disease. Since the identification of the causative mutation, biomedical research of SMA has progressed by leaps and bounds: from clues on the function of SMN protein, to the development of different models of the disease, to the identification of potential treatments, some of which are currently in human trials. The aim of this review is to elucidate the current state of knowledge, emphasizing how close we are to the solution of the puzzle that is SMA, and, more importantly, to highlight the missing pieces of this puzzle. Filling in these gaps in our knowledge will likely accelerate the development and delivery of efficient treatments for SMA patients and be a prerequisite towards achieving our final goal, the cure of SMA.
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334
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Lunke S, El-Osta A. Applicability of histone deacetylase inhibition for the treatment of spinal muscular atrophy. Neurotherapeutics 2013; 10:677-87. [PMID: 23996601 PMCID: PMC3805858 DOI: 10.1007/s13311-013-0209-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Spinal muscular atrophy (SMA), a neurodegenerative disease with potentially devastating and even deadly effects on affected individuals, was first described in the late nineteenth century. Although the survival of motor neuron (SMN) gene was identified nearly 2 decades ago to be causative of the disease, neither an effective treatment nor a cure are currently available. Yet efforts are on-going to test a multitude of treatment strategies with the potential to alleviate disease symptoms in human and clinical trials. Among the most studied compounds for the treatment of SMA are histone deacetylase inhibitors. Several of these epigenetic modifiers have been shown to increase expression of the crucial SMN gene in vitro and in vivo, an effect linked to increased histone acetylation and remodeling of the chromatin landscape surrounding the SMN gene promoter. Here, we review the history and current state of use of histone deacetylase inhibitors in SMA, as well as the success of clinical trials investigating the clinical applicability of these epigenetic modifiers in SMA treatment.
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Affiliation(s)
- Sebastian Lunke
- />Epigenetics in Human Health and Disease Laboratory, Baker IDI Heart and Diabetes Institute, The Alfred Medical Research and Education Precinct, Melbourne, VIC 3004 Australia
- />Translational Genomics Laboratory, Centre for Translational Pathology, Department of Pathology, University of Melbourne, Melbourne, VIC 3010 Australia
| | - Assam El-Osta
- />Epigenetics in Human Health and Disease Laboratory, Baker IDI Heart and Diabetes Institute, The Alfred Medical Research and Education Precinct, Melbourne, VIC 3004 Australia
- />Epigenomics Profiling Facility, Baker IDI Heart and Diabetes Institute, The Alfred Medical Research and Education Precinct, Melbourne, VIC Australia
- />Department of Pathology, The University of Melbourne, Melbourne, VIC Australia
- />Faculty of Medicine, Monash University, Monash, VIC Australia
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335
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Sahashi K, Ling KKY, Hua Y, Wilkinson JE, Nomakuchi T, Rigo F, Hung G, Xu D, Jiang YP, Lin RZ, Ko CP, Bennett CF, Krainer AR. Pathological impact of SMN2 mis-splicing in adult SMA mice. EMBO Mol Med 2013; 5:1586-601. [PMID: 24014320 PMCID: PMC3799581 DOI: 10.1002/emmm.201302567] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 08/06/2013] [Accepted: 08/09/2013] [Indexed: 12/18/2022] Open
Abstract
Loss-of-function mutations in SMN1 cause spinal muscular atrophy (SMA), a leading genetic cause of infant mortality. The related SMN2 gene expresses suboptimal levels of functional SMN protein, due to a splicing defect. Many SMA patients reach adulthood, and there is also adult-onset (type IV) SMA. There is currently no animal model for adult-onset SMA, and the tissue-specific pathogenesis of post-developmental SMN deficiency remains elusive. Here, we use an antisense oligonucleotide (ASO) to exacerbate SMN2 mis-splicing. Intracerebroventricular ASO injection in adult SMN2-transgenic mice phenocopies key aspects of adult-onset SMA, including delayed-onset motor dysfunction and relevant histopathological features. SMN2 mis-splicing increases during late-stage disease, likely accelerating disease progression. Systemic ASO injection in adult mice causes peripheral SMN2 mis-splicing and affects prognosis, eliciting marked liver and heart pathologies, with decreased IGF1 levels. ASO dose–response and time-course studies suggest that only moderate SMN levels are required in the adult central nervous system, and treatment with a splicing-correcting ASO shows a broad therapeutic time window. We describe distinctive pathological features of adult-onset and early-onset SMA.
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336
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Seo J, Howell MD, Singh NN, Singh RN. Spinal muscular atrophy: an update on therapeutic progress. Biochim Biophys Acta Mol Basis Dis 2013; 1832:2180-90. [PMID: 23994186 DOI: 10.1016/j.bbadis.2013.08.005] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 07/27/2013] [Accepted: 08/14/2013] [Indexed: 12/24/2022]
Abstract
Humans have two nearly identical copies of survival motor neuron gene: SMN1 and SMN2. Deletion or mutation of SMN1 combined with the inability of SMN2 to compensate for the loss of SMN1 results in spinal muscular atrophy (SMA), a leading genetic cause of infant mortality. SMA affects 1 in ~6000 live births, a frequency much higher than in several genetic diseases. The major known defect of SMN2 is the predominant exon 7 skipping that leads to production of a truncated protein (SMNΔ7), which is unstable. Therefore, SMA has emerged as a model genetic disorder in which almost the entire disease population could be linked to the aberrant splicing of a single exon (i.e. SMN2 exon 7). Diverse treatment strategies aimed at improving the function of SMN2 have been envisioned. These strategies include, but are not limited to, manipulation of transcription, correction of aberrant splicing and stabilization of mRNA, SMN and SMNΔ7. This review summarizes up to date progress and promise of various in vivo studies reported for the treatment of SMA.
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Affiliation(s)
- Joonbae Seo
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA
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337
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Goulet BB, McFall ER, Wong CM, Kothary R, Parks RJ. Supraphysiological expression of survival motor neuron protein from an adenovirus vector does not adversely affect cell function. Biochem Cell Biol 2013; 91:252-64. [DOI: 10.1139/bcb-2012-0094] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Spinal muscular atrophy (SMA) is the most common inherited neurodegenerative disease that leads to infant mortality. It is caused by mutations in the survival motor neuron (SMN) protein resulting in death of alpha motor neurons. Increasing evidence suggests that several other tissues are also affected in SMA, including skeletal and cardiac muscle, liver, and pancreas, indicating that systemic delivery of therapeutics may be necessary for true disease correction. Due to the natural biodistribution of therapeutics, a level of SMN several-fold above physiological levels can be achieved in some tissues. In this study, we address whether supraphysiological levels of SMN adversely affects cell function. Infection of a variety of cell types with an adenovirus (Ad) vector encoding SMN leads to very high expression, but the resulting protein correctly localizes within the cell, and associates with normal cellular partners. Although SMN affects transcription of certain target genes and can alter the splicing pattern of others, we did not observe any difference in select target gene splicing or expression in cells overexpressing SMN. However, normal human fibroblasts treated with Ad-SMN showed a slight reduction in growth rate, suggesting that certain cell types may be differently impacted by high levels of SMN.
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Affiliation(s)
- Benoit B. Goulet
- Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON K1H 8L6, Canada
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Emily R. McFall
- Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON K1H 8L6, Canada
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Carmen M. Wong
- Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON K1H 8L6, Canada
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Rashmi Kothary
- Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON K1H 8L6, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Robin J. Parks
- Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON K1H 8L6, Canada
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
- Department of Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
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338
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Nurputra DK, Lai PS, Harahap NIF, Morikawa S, Yamamoto T, Nishimura N, Kubo Y, Takeuchi A, Saito T, Takeshima Y, Tohyama Y, Tay SKH, Low PS, Saito K, Nishio H. Spinal muscular atrophy: from gene discovery to clinical trials. Ann Hum Genet 2013; 77:435-63. [PMID: 23879295 DOI: 10.1111/ahg.12031] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 04/26/2013] [Indexed: 12/25/2022]
Abstract
Spinal muscular atrophy (SMA) is a common neuromuscular disorder with autosomal recessive inheritance, resulting in the degeneration of motor neurons. The incidence of the disease has been estimated at 1 in 6000-10,000 newborns with a carrier frequency of 1 in 40-60. SMA is caused by mutations of the SMN1 gene, located on chromosome 5q13. The gene product, survival motor neuron (SMN) plays critical roles in a variety of cellular activities. SMN2, a homologue of SMN1, is retained in all SMA patients and generates low levels of SMN, but does not compensate for the mutated SMN1. Genetic analysis demonstrates the presence of homozygous deletion of SMN1 in most patients, and allows screening of heterozygous carriers in affected families. Considering high incidence of carrier frequency in SMA, population-wide newborn and carrier screening has been proposed. Although no effective treatment is currently available, some treatment strategies have already been developed based on the molecular pathophysiology of this disease. Current treatment strategies can be classified into three major groups: SMN2-targeting, SMN1-introduction, and non-SMN targeting. Here, we provide a comprehensive and up-to-date review integrating advances in molecular pathophysiology and diagnostic testing with therapeutic developments for this disease including promising candidates from recent clinical trials.
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Affiliation(s)
- Dian K Nurputra
- Department of Community Medicine and Social Health Care, Kobe University Graduate School of Medicine, Kobe, Japan
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339
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Shababi M, Lorson CL, Rudnik-Schöneborn SS. Spinal muscular atrophy: a motor neuron disorder or a multi-organ disease? J Anat 2013; 224:15-28. [PMID: 23876144 DOI: 10.1111/joa.12083] [Citation(s) in RCA: 158] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2013] [Indexed: 12/13/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive disorder that is the leading genetic cause of infantile death. SMA is characterized by loss of motor neurons in the ventral horn of the spinal cord, leading to weakness and muscle atrophy. SMA occurs as a result of homozygous deletion or mutations in Survival Motor Neuron-1 (SMN1). Loss of SMN1 leads to a dramatic reduction in SMN protein, which is essential for motor neuron survival. SMA disease severity ranges from extremely severe to a relatively mild adult onset form of proximal muscle atrophy. Severe SMA patients typically die mostly within months or a few years as a consequence of respiratory insufficiency and bulbar paralysis. SMA is widely known as a motor neuron disease; however, there are numerous clinical reports indicating the involvement of additional peripheral organs contributing to the complete picture of the disease in severe cases. In this review, we have compiled clinical and experimental reports that demonstrate the association between the loss of SMN and peripheral organ deficiency and malfunction. Whether defective peripheral organs are a consequence of neuronal damage/muscle atrophy or a direct result of SMN loss will be discussed.
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Affiliation(s)
- Monir Shababi
- Department of Veterinary Pathobiology, Life Sciences Center, University of Missouri, Columbia, MO, USA; Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO, USA
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340
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Wang Z, Jeon HY, Rigo F, Bennett CF, Krainer AR. Manipulation of PK-M mutually exclusive alternative splicing by antisense oligonucleotides. Open Biol 2013; 2:120133. [PMID: 23155487 PMCID: PMC3498831 DOI: 10.1098/rsob.120133] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Accepted: 10/11/2012] [Indexed: 12/23/2022] Open
Abstract
Alternative splicing of the pyruvate kinase M gene involves a choice between mutually exclusive exons 9 and 10. Use of exon 10 to generate the M2 isoform is crucial for aerobic glycolysis (the Warburg effect) and tumour growth. We previously demonstrated that splicing enhancer elements that activate exon 10 are mainly found in exon 10 itself, and deleting or mutating these elements increases the inclusion of exon 9 in cancer cells. To systematically search for new enhancer elements in exon 10 and develop an effective pharmacological method to force a switch from PK-M2 to PK-M1, we carried out an antisense oligonucleotide (ASO) screen. We found potent ASOs that target a novel enhancer in exon 10 and strongly switch the splicing of endogenous PK-M transcripts to include exon 9. We further show that the ASO-mediated switch in alternative splicing leads to apoptosis in glioblastoma cell lines, and this is caused by the downregulation of PK-M2, and not by the upregulation of PK-M1. These data highlight the potential of ASO-mediated inhibition of PK-M2 splicing as therapy for cancer.
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Affiliation(s)
- Zhenxun Wang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724 , USA; Watson School of Biological Sciences, Cold Spring Harbor, NY 11724, USA
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341
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Abstract
Adequate therapies are lacking for Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, and other neurodegenerative diseases. The ability to use antisense oligonucleotides (ASOs) to target disease-associated genes by means of RNA may offer a potent approach for the treatment of these, and other, neurodegenerative disorders. In modifying the basic backbone chemistry, chemical groups, and target sequence, ASOs can act through numerous mechanisms to decrease or increase total protein levels, preferentially shift splicing patterns, and inhibit microRNAs, all at the level of the RNA molecule. Here, we discuss many of the more commonly used ASO chemistries, as well as the different mechanisms of action that can result from these specific chemical modifications. When applied to multiple neurodegenerative mouse models, ASOs that specifically target the detrimental transgenes have been shown to rescue disease associated phenotypes in vivo. These supporting mouse model data have moved the ASOs from the bench to the clinic, with two neuro-focused human clinical trials now underway and several more being proposed. Although still early in development, translating ASOs into human patients for neurodegeneration appears promising.
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Affiliation(s)
- Sarah L. DeVos
- Department of Neurology, Washington University in St. Louis School of Medicine, St. Louis, MO 63110 USA
| | - Timothy M. Miller
- Department of Neurology, Washington University in St. Louis School of Medicine, St. Louis, MO 63110 USA
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342
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Cherry JJ, Osman EY, Evans MC, Choi S, Xing X, Cuny GD, Glicksman MA, Lorson CL, Androphy EJ. Enhancement of SMN protein levels in a mouse model of spinal muscular atrophy using novel drug-like compounds. EMBO Mol Med 2013; 5:1103-18. [PMID: 23740718 PMCID: PMC3721476 DOI: 10.1002/emmm.201202305] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 03/27/2013] [Accepted: 04/02/2013] [Indexed: 12/22/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disease that causes progressive muscle weakness, which primarily targets proximal muscles. About 95% of SMA cases are caused by the loss of both copies of the SMN1 gene. SMN2 is a nearly identical copy of SMN1, which expresses much less functional SMN protein. SMN2 is unable to fully compensate for the loss of SMN1 in motor neurons but does provide an excellent target for therapeutic intervention. Increased expression of functional full-length SMN protein from the endogenous SMN2 gene should lessen disease severity. We have developed and implemented a new high-throughput screening assay to identify small molecules that increase the expression of full-length SMN from a SMN2 reporter gene. Here, we characterize two novel compounds that increased SMN protein levels in both reporter cells and SMA fibroblasts and show that one increases lifespan, motor function, and SMN protein levels in a severe mouse model of SMA.
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Affiliation(s)
- Jonathan J Cherry
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA
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343
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Gogliotti RG, Cardona H, Singh J, Bail S, Emery C, Kuntz N, Jorgensen M, Durens M, Xia B, Barlow C, Heier CR, Plasterer HL, Jacques V, Kiledjian M, Jarecki J, Rusche J, DiDonato CJ. The DcpS inhibitor RG3039 improves survival, function and motor unit pathologies in two SMA mouse models. Hum Mol Genet 2013; 22:4084-101. [PMID: 23736298 DOI: 10.1093/hmg/ddt258] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Spinal muscular atrophy (SMA) is caused by insufficient levels of the survival motor neuron (SMN) protein due to the functional loss of the SMN1 gene and the inability of its paralog, SMN2, to fully compensate due to reduced exon 7 splicing efficiency. Since SMA patients have at least one copy of SMN2, drug discovery campaigns have sought to identify SMN2 inducers. C5-substituted quinazolines increase SMN2 promoter activity in cell-based assays and a derivative, RG3039, has progressed to clinical testing. It is orally bioavailable, brain-penetrant and has been shown to be an inhibitor of the mRNA decapping enzyme, DcpS. Our pharmacological characterization of RG3039, reported here, demonstrates that RG3039 can extend survival and improve function in two SMA mouse models of varying disease severity (Taiwanese 5058 Hemi and 2B/- SMA mice), and positively impacts neuromuscular pathologies. In 2B/- SMA mice, RG3039 provided a >600% survival benefit (median 18 days to >112 days) when dosing began at P4, highlighting the importance of early intervention. We determined the minimum effective dose and the associated pharmacokinetic (PK) and exposure relationship of RG3039 and DcpS inhibition ex vivo. These data support the long PK half-life with extended pharmacodynamic outcome of RG3039 in 2B/- SMA mice. In motor neurons, RG3039 significantly increased both the average number of cells with gems and average number of gems per cell, which is used as an indirect measure of SMN levels. These studies contribute to dose selection and exposure estimates for the first studies with RG3039 in human subjects.
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344
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Abstract
Because pediatric intensive care units (PICUs) improve survival for a range of acute diseases, attention has turned toward ensuring the best possible functional outcomes after critical illness. The neurocritical care of children is of increasing interest. However, the pediatric population encompasses a heterogeneous set of neurologic conditions, with several possible models of how best to address them. This article reviews the special challenges faced by PICUs with regards to diseases, technologies, and skills and the progress that has been made in treatment, monitoring, and prognostication. Recent advances in translational research expected to modify the field in the near-term are described.
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Affiliation(s)
- Joshua Cappell
- Pediatric Critical Care Medicine, Department of Pediatrics, Morgan Stanley Children's Hospital, Columbia University Medical Center, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
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345
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DeVos SL, Miller TM. Direct intraventricular delivery of drugs to the rodent central nervous system. J Vis Exp 2013:e50326. [PMID: 23712122 PMCID: PMC3679837 DOI: 10.3791/50326] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Due to an inability to cross the blood brain barrier, certain drugs need to be directly delivered into the central nervous system (CNS). Our lab focuses specifically on antisense oligonucleotides (ASOs), though the techniques shown in the video here can also be used to deliver a plethora of other drugs to the CNS. Antisense oligonucleotides (ASOs) have the capability to knockdown sequence-specific targets 1 as well as shift isoform ratios of specific genes 2. To achieve widespread gene knockdown or splicing in the CNS of mice, the ASOs can be delivered into the brain using two separate routes of administration, both of which we demonstrate in the video. The first uses Alzet osmotic pumps, connected to a catheter that is surgically implanted into the lateral ventricle. This allows the ASOs to be continuously infused into the CNS for a designated period of time. The second involves a single bolus injection of a high concentration of ASO into the right lateral ventricle. Both methods use the mouse cerebral ventricular system to deliver the ASO to the entire brain and spinal cord, though depending on the needs of the study, one method may be preferred over the other.
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Affiliation(s)
- Sarah L DeVos
- Department of Neurology, Washington University in St. Louis School of Medicine, USA
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346
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Liew WKM, Kang PB. Recent developments in the treatment of Duchenne muscular dystrophy and spinal muscular atrophy. Ther Adv Neurol Disord 2013; 6:147-60. [PMID: 23634188 DOI: 10.1177/1756285612472386] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Pediatric neuromuscular disorders comprise a large variety of disorders that can be classified based on their neuroanatomical localization, patterns of weakness, and laboratory test results. Over the last decade, the field of translational research has been active with many ongoing clinical trials. This is particularly so in two common pediatric neuromuscular disorders: Duchenne muscular dystrophy and spinal muscular atrophy. Although no definitive therapy has yet been found, numerous active areas of research raise the potential for novel therapies in these two disorders, offering hope for improved quality of life and life expectancy for affected individuals.
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Affiliation(s)
- Wendy K M Liew
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, USA and Neurology service, Department of Paediatric Medicine, KK Women's and Children's Hospital, Singapore
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347
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Havens MA, Duelli DM, Hastings ML. Targeting RNA splicing for disease therapy. WILEY INTERDISCIPLINARY REVIEWS. RNA 2013; 4:247-66. [PMID: 23512601 PMCID: PMC3631270 DOI: 10.1002/wrna.1158] [Citation(s) in RCA: 128] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Splicing of pre-messenger RNA into mature messenger RNA is an essential step for the expression of most genes in higher eukaryotes. Defects in this process typically affect cellular function and can have pathological consequences. Many human genetic diseases are caused by mutations that cause splicing defects. Furthermore, a number of diseases are associated with splicing defects that are not attributed to overt mutations. Targeting splicing directly to correct disease-associated aberrant splicing is a logical approach to therapy. Splicing is a favorable intervention point for disease therapeutics, because it is an early step in gene expression and does not alter the genome. Significant advances have been made in the development of approaches to manipulate splicing for therapy. Splicing can be manipulated with a number of tools including antisense oligonucleotides, modified small nuclear RNAs (snRNAs), trans-splicing, and small molecule compounds, all of which have been used to increase specific alternatively spliced isoforms or to correct aberrant gene expression resulting from gene mutations that alter splicing. Here we describe clinically relevant splicing defects in disease states, the current tools used to target and alter splicing, specific mutations and diseases that are being targeted using splice-modulating approaches, and emerging therapeutics.
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Affiliation(s)
- Mallory A. Havens
- Department of Cell Biology and Anatomy, Chicago Medical School, Rosalind Franklin University of Medicine and Science. North Chicago, IL, 60064, USA. No conflicts of interest
| | - Dominik M. Duelli
- Department of Cellular and Molecular Pharmacology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, 60064, USA. No conflicts of interest
| | - Michelle L. Hastings
- Department of Cell Biology and Anatomy, Chicago Medical School, Rosalind Franklin University of Medicine and Science. North Chicago, IL, 60064, USA, Phone: 847-578-8517 Fax: 847-578-3253. No conflicts of interest
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348
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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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349
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Mitrpant C, Porensky P, Zhou H, Price L, Muntoni F, Fletcher S, Wilton SD, Burghes AHM. Improved antisense oligonucleotide design to suppress aberrant SMN2 gene transcript processing: towards a treatment for spinal muscular atrophy. PLoS One 2013; 8:e62114. [PMID: 23630626 PMCID: PMC3632594 DOI: 10.1371/journal.pone.0062114] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2012] [Accepted: 03/18/2013] [Indexed: 12/20/2022] Open
Abstract
Spinal muscular atrophy (SMA) is caused by loss of the Survival Motor Neuron 1 (SMN1) gene, resulting in reduced SMN protein. Humans possess the additional SMN2 gene (or genes) that does produce low level of full length SMN, but cannot adequately compensate for loss of SMN1 due to aberrant splicing. The majority of SMN2 gene transcripts lack exon 7 and the resultant SMNΔ7 mRNA is translated into an unstable and non-functional protein. Splice intervention therapies to promote exon 7 retention and increase amounts of full-length SMN2 transcript offer great potential as a treatment for SMA patients. Several splice silencing motifs in SMN2 have been identified as potential targets for antisense oligonucleotide mediated splice modification. A strong splice silencer is located downstream of exon 7 in SMN2 intron 7. Antisense oligonucleotides targeting this motif promoted SMN2 exon 7 retention in the mature SMN2 transcripts, with increased SMN expression detected in SMA fibroblasts. We report here systematic optimisation of phosphorodiamidate morpholino oligonucleotides (PMO) that promote exon 7 retention to levels that rescued the phenotype in a severe mouse model of SMA after intracerebroventricular delivery. Furthermore, the PMO gives the longest survival reported to date after a single dosing by ICV.
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MESH Headings
- Animals
- Base Sequence
- Cells, Cultured
- Genetic Therapy
- Humans
- Injections, Intraventricular
- Mice
- Mice, Transgenic
- Morpholinos/genetics
- Muscular Atrophy, Spinal/genetics
- Muscular Atrophy, Spinal/therapy
- Oligonucleotides, Antisense/genetics
- RNA Interference
- RNA Processing, Post-Transcriptional
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Survival of Motor Neuron 2 Protein/genetics
- Survival of Motor Neuron 2 Protein/metabolism
- Titrimetry
- Transcription, Genetic
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Affiliation(s)
- Chalermchai Mitrpant
- Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, QE II Medical Centre, Perth, Western Australia, Australia
- Department of Biochemistry, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
- * E-mail: (CM); (AHMB)
| | - Paul Porensky
- Department of Neurological Surgery, The Wexner Ohio State University Medical Center, Columbus, Ohio, United States of America
| | - Haiyan Zhou
- Dubowitz Neuromuscular Centre, Institute of Child Health and Great Ormond Street Hospital, London, United Kingdom
| | - Loren Price
- Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, QE II Medical Centre, Perth, Western Australia, Australia
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, Institute of Child Health and Great Ormond Street Hospital, London, United Kingdom
| | - Sue Fletcher
- Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, QE II Medical Centre, Perth, Western Australia, Australia
| | - Steve D. Wilton
- Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, QE II Medical Centre, Perth, Western Australia, Australia
| | - Arthur H. M. Burghes
- Department of Molecular and Cellular Biochemistry and Neurology, The Wexner Ohio State University Medical Center, Columbus, Ohio, United States of America
- * E-mail: (CM); (AHMB)
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Miller TM, Pestronk A, David W, Rothstein J, Simpson E, Appel SH, Andres PL, Mahoney K, Allred P, Alexander K, Ostrow LW, Schoenfeld D, Macklin EA, Norris DA, Manousakis G, Crisp M, Smith R, Bennett CF, Bishop KM, Cudkowicz ME. An antisense oligonucleotide against SOD1 delivered intrathecally for patients with SOD1 familial amyotrophic lateral sclerosis: a phase 1, randomised, first-in-man study. Lancet Neurol 2013; 12:435-42. [PMID: 23541756 DOI: 10.1016/s1474-4422(13)70061-9] [Citation(s) in RCA: 467] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND Mutations in SOD1 cause 13% of familial amyotrophic lateral sclerosis. In the SOD1 Gly93Ala rat model of amyotrophic lateral sclerosis, the antisense oligonucleotide ISIS 333611 delivered to CSF decreased SOD1 mRNA and protein concentrations in spinal cord tissue and prolonged survival. We aimed to assess the safety, tolerability, and pharmacokinetics of ISIS 333611 after intrathecal administration in patients with SOD1-related familial amyotrophic lateral sclerosis. METHODS In this randomised, placebo-controlled, phase 1 trial, we delivered ISIS 333611 by intrathecal infusion using an external pump over 11·5 h at increasing doses (0·15 mg, 0·50 mg, 1·50 mg, 3·00 mg) to four cohorts of eight patients with SOD1-positive amyotrophic lateral sclerosis (six patients assigned to ISIS 333611, two to placebo in each cohort). We did the randomisation with a web-based system, assigning patients in blocks of four. Patients and investigators were masked to treatment assignment. Participants were allowed to re-enrol in subsequent cohorts. Our primary objective was to assess the safety and tolerability of ISIS 333611. Assessments were done during infusion and over 28 days after infusion. This study was registered with Clinicaltrials.gov, number NCT01041222. FINDINGS Seven of eight (88%) patients in the placebo group versus 20 of 24 (83%) in the ISIS 333611 group had adverse events. The most common events were post-lumbar puncture syndrome (3/8 [38%] vs 8/24 [33%]), back pain (4/8 [50%] vs 4/24 [17%]), and nausea (0/8 [0%] vs 3/24 [13%]). We recorded no dose-limiting toxic effects or any safety or tolerability concerns related to ISIS 333611. No serious adverse events occurred in patients given ISIS 333611. Re-enrolment and re-treatment were also well tolerated. INTERPRETATION This trial is the first clinical study of intrathecal delivery of an antisense oligonucleotide. ISIS 333611 was well tolerated when administered as an intrathecal infusion. Antisense oligonucleotides delivered to the CNS might be a feasible treatment for neurological disorders. FUNDING The ALS Association, Muscular Dystrophy Association, Isis Pharmaceuticals.
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