1
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Signoria I, van der Pol WL, Groen EJN. Innovating spinal muscular atrophy models in the therapeutic era. Dis Model Mech 2023; 16:dmm050352. [PMID: 37787662 PMCID: PMC10565113 DOI: 10.1242/dmm.050352] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a severe, monogenetic, neuromuscular disease. A thorough understanding of its genetic cause and the availability of robust models has led to the development and approval of three gene-targeting therapies. This is a unique and exciting development for the field of neuromuscular diseases, many of which remain untreatable. The development of therapies for SMA not only opens the door to future therapeutic possibilities for other genetic neuromuscular diseases, but also informs us about the limitations of such treatments. For example, treatment response varies widely and, for many patients, significant disability remains. Currently available SMA models best recapitulate the severe types of SMA, and these models are genetically and phenotypically more homogeneous than patients. Furthermore, treating patients is leading to a shift in phenotypes with increased variability in SMA clinical presentation. Therefore, there is a need to generate model systems that better reflect these developments. Here, we will first discuss current animal models of SMA and their limitations. Next, we will discuss the characteristics required to future-proof models to assist the field in the development of additional, novel therapies for SMA.
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Affiliation(s)
- Ilaria Signoria
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - W. Ludo van der Pol
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Ewout J. N. Groen
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
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2
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Arbab M, Matuszek Z, Kray KM, Du A, Newby GA, Blatnik AJ, Raguram A, Richter MF, Zhao KT, Levy JM, Shen MW, Arnold WD, Wang D, Xie J, Gao G, Burghes AHM, Liu DR. Base editing rescue of spinal muscular atrophy in cells and in mice. Science 2023; 380:eadg6518. [PMID: 36996170 PMCID: PMC10270003 DOI: 10.1126/science.adg6518] [Citation(s) in RCA: 54] [Impact Index Per Article: 54.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 03/21/2023] [Indexed: 04/01/2023]
Abstract
Spinal muscular atrophy (SMA), the leading genetic cause of infant mortality, arises from survival motor neuron (SMN) protein insufficiency resulting from SMN1 loss. Approved therapies circumvent endogenous SMN regulation and require repeated dosing or may wane. We describe genome editing of SMN2, an insufficient copy of SMN1 harboring a C6>T mutation, to permanently restore SMN protein levels and rescue SMA phenotypes. We used nucleases or base editors to modify five SMN2 regulatory regions. Base editing converted SMN2 T6>C, restoring SMN protein levels to wild type. Adeno-associated virus serotype 9-mediated base editor delivery in Δ7SMA mice yielded 87% average T6>C conversion, improved motor function, and extended average life span, which was enhanced by one-time base editor and nusinersen coadministration (111 versus 17 days untreated). These findings demonstrate the potential of a one-time base editing treatment for SMA.
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Affiliation(s)
- Mandana Arbab
- Department of Neurology, Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Boston, MA 02115, USA
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Zaneta Matuszek
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Kaitlyn M. Kray
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, 1060 Carmack Road, Columbus, OH 43210, USA
| | - Ailing Du
- Horae Gene Therapy Center, University of Massachusetts, Medical School, Worcester, MA 01605, USA
| | - Gregory A. Newby
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Anton J. Blatnik
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, 1060 Carmack Road, Columbus, OH 43210, USA
| | - Aditya Raguram
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Michelle F. Richter
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Kevin T. Zhao
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Jonathan M. Levy
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Max W. Shen
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
- Computational and Systems Biology Program, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - W. David Arnold
- Department of Neurology, The Ohio State University Wexner Medical Center, 1060 Carmack Road, Columbus, OH 43210, USA
- NextGen Precision Health, University of Missouri, Columbia, MO 65212, USA
| | - Dan Wang
- Horae Gene Therapy Center, University of Massachusetts, Medical School, Worcester, MA 01605, USA
- Horae Gene Therapy Center and RNA Therapeutics Institute, University of Massachusetts, Medical School, Worcester, MA 01605, USA
| | - Jun Xie
- Horae Gene Therapy Center, University of Massachusetts, Medical School, Worcester, MA 01605, USA
| | - Guangping Gao
- Horae Gene Therapy Center, University of Massachusetts, Medical School, Worcester, MA 01605, USA
- Microbiology and Physiological Systems, University of Massachusetts, Medical School, Worcester, MA 01605, USA
| | - Arthur H. M. Burghes
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, 1060 Carmack Road, Columbus, OH 43210, USA
| | - David R. Liu
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA
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3
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Shababi M, Smith CE, Ricardez Hernandez SM, Marquez J, Al Rawi Z, Villalón E, Farris KD, Garro-Kacher MO, Lorson CL. Defining the optimal dose and therapeutic window in SMA with respiratory distress type I model mice, FVB/NJ- Ighmpb2 nmd-2J. Mol Ther Methods Clin Dev 2021; 23:23-32. [PMID: 34553000 PMCID: PMC8426477 DOI: 10.1016/j.omtm.2021.07.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 07/30/2021] [Indexed: 11/23/2022]
Abstract
Spinal muscular atrophy with respiratory distress type 1 (SMARD1) is an autosomal recessive disorder that develops in infancy and arises from mutation of the immunoglobulin helicase μ-binding protein 2 (IGHMBP2) gene. Whereas IGHMBP2 is ubiquitously expressed, loss or reduction of function leads to alpha motor neuron loss and skeletal muscle atrophy. We previously developed a gene therapy strategy for SMARD1 using a single-stranded AAV9-IGHMBP2 vector and compared two different delivery methods in a validated SMARD1 mouse model. An important question in the field relates to the temporal requirements for this or any potential treatment. To examine the therapeutic window, we utilized our recently developed SMARD1 model, FVB/NJ-Ighmpb2 nmd-2J , to deliver AAV9-IGHMBP2 at four different time points starting at post-natal day 2 (P2) through P8. At each time point, significant improvements were observed in survival, weight gain, and motor function. Similarly, treatment improved important hallmarks of disease, including motor unit pathology. Whereas improvements were more pronounced in the early-treatment groups, even the later-treatment groups displayed significant phenotypic improvements. This work suggests that an effective gene therapy strategy could provide benefits to pre-symptomatic and early-symptomatic individuals, thereby expanding the potential therapeutic window for SMARD1.
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Affiliation(s)
- Monir Shababi
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Caley E. Smith
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | | | - Jose Marquez
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Zayd Al Rawi
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Eric Villalón
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - K. David Farris
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Mona O. Garro-Kacher
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Christian L. Lorson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
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4
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Behera B. Nusinersen, an exon 7 inclusion drug for spinal muscular atrophy: A minireview. World J Meta-Anal 2021; 9:277-285. [DOI: 10.13105/wjma.v9.i3.277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 05/20/2021] [Accepted: 06/17/2021] [Indexed: 02/06/2023] Open
Abstract
Spinal muscular atrophy is an autosomal recessive neuromuscular disease with incidence of 1 in 5000 to 10000 live births and is produced by homozygous deletion of exons 7 and 8 in the SMN1 gene. The SMN1 and SMN2 genes encode the survival motor neuron protein, a crucial protein for the preservation of motor neurons. Use of the newer drug, Nusinersen, from early infancy has shown improvement in clinical outcomes of spinal muscular atrophy patients.
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Affiliation(s)
- Bijaylaxmi Behera
- Department of Neonatology, Chaitanya Hospital, Chandigarh 160044, India
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5
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Deguise MO, Beauvais A, Schneider BL, Kothary R. Blood Flow to the Spleen is Altered in a Mouse Model of Spinal Muscular Atrophy. J Neuromuscul Dis 2021; 7:315-322. [PMID: 32333548 DOI: 10.3233/jnd-200493] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disorder affecting young children. While pre-clinical models of SMA show small spleens, the same is not true in humans. Here, we show by doppler ultrasonography decreased splenic blood flow in Smn2B/- mice. Further, AAV9-SMN gene therapy does not rescue the distal ear and tail necrosis nor the spleen size in these mice, suggesting that the latter may be linked to a cardiovascular defect. Absence of smaller spleens in human patients is likely due to differences in presentation of defects in SMA between pre-clinical mouse models and human patients, particularly the susceptibility to cardiovascular issues.
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Affiliation(s)
- Marc-Olivier Deguise
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada.,Centre for Neuromuscular Disease, University of Ottawa, Ottawa, Ontario, Canada
| | - Ariane Beauvais
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Bernard L Schneider
- Bertarelli Foundation Gene Therapy Platform, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1202 Geneva, Switzerland.,Brain Mind Institute, 27218 Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Rashmi Kothary
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada.,Centre for Neuromuscular Disease, University of Ottawa, Ottawa, Ontario, Canada.,Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, and Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
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6
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Abstract
Research and drug development concerning rare diseases are at the cutting edge of scientific technology. To date, over 7,000 rare diseases have been identified. Despite their individual rarity, 1 in 10 individuals worldwide is affected by a rare condition. For the majority of these diseases, there is no treatment, much less cure; therefore, there is an urgent need for new therapies to extend and improve quality of life for persons who suffer from them. Here we focus specifically on rare neuromuscular diseases. Currently, genetic medicines using short antisense oligonucleotides (ASO) or small interfering ribonucleic acids that target RNA transcripts are achieving spectacular success in treating these diseases. For Duchenne muscular dystrophy (DMD), the state-of-the-art is an exon skipping therapy using an antisense oligonucleotide, which is prototypical of advanced precision medicines. Very recently, golodirsen and viltolarsen, for treatment of DMD patients amenable to skipping exon 53, have been approved by regulatory agencies in the USA and Japan, respectively. Here, we review scientific and clinical progress in developing new oligonucleotide therapeutics for selected rare neuromuscular diseases, discussing their efficacy and limitations.
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Affiliation(s)
- Yoshitsugu Aoki
- Department of Molecular Therapy, National Institute of Neuroscience, National Centre of Neurology and Psychiatry, Kodaira-shi, Tokyo, Japan
| | - Matthew J.A. Wood
- Department of Paediatrics, University of Oxford, Oxford, UK
- Oxford Harrington Rare Disease Centre, University of Oxford, John Radcliffe Hospital, Oxford, UK
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7
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New and Developing Therapies in Spinal Muscular Atrophy: From Genotype to Phenotype to Treatment and Where Do We Stand? Int J Mol Sci 2020; 21:ijms21093297. [PMID: 32392694 PMCID: PMC7246502 DOI: 10.3390/ijms21093297] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 05/03/2020] [Accepted: 05/04/2020] [Indexed: 02/08/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a congenital neuromuscular disorder characterized by motor neuron loss, resulting in progressive weakness. SMA is notable in the health care community because it accounts for the most common cause of infant death resulting from a genetic defect. SMA is caused by low levels of the survival motor neuron protein (SMN) resulting from SMN1 gene mutations or deletions. However, patients always harbor various copies of SMN2, an almost identical but functionally deficient copy of the gene. A genotype–phenotype correlation suggests that SMN2 is a potent disease modifier for SMA, which also represents the primary target for potential therapies. Increasing comprehension of SMA pathophysiology, including the characterization of SMN1 and SMN2 genes and SMN protein functions, has led to the development of multiple therapeutic approaches. Until the end of 2016, no cure was available for SMA, and management consisted of supportive measures. Two breakthrough SMN-targeted treatments, either using antisense oligonucleotides (ASOs) or virus-mediated gene therapy, have recently been approved. These two novel therapeutics have a common objective: to increase the production of SMN protein in MNs and thereby improve motor function and survival. However, neither therapy currently provides a complete cure. Treating patients with SMA brings new responsibilities and unique dilemmas. As SMA is such a devastating disease, it is reasonable to assume that a unique therapeutic solution may not be sufficient. Current approaches under clinical investigation differ in administration routes, frequency of dosing, intrathecal versus systemic delivery, and mechanisms of action. Besides, emerging clinical trials evaluating the efficacy of either SMN-dependent or SMN-independent approaches are ongoing. This review aims to address the different knowledge gaps between genotype, phenotypes, and potential therapeutics.
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8
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Deguise MO, De Repentigny Y, Tierney A, Beauvais A, Michaud J, Chehade L, Thabet M, Paul B, Reilly A, Gagnon S, Renaud JM, Kothary R. Motor transmission defects with sex differences in a new mouse model of mild spinal muscular atrophy. EBioMedicine 2020; 55:102750. [PMID: 32339936 PMCID: PMC7184161 DOI: 10.1016/j.ebiom.2020.102750] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 02/25/2020] [Accepted: 03/19/2020] [Indexed: 12/31/2022] Open
Abstract
Background Mouse models of mild spinal muscular atrophy (SMA) have been extremely challenging to generate. This paucity of model systems has limited our understanding of pathophysiological events in milder forms of the disease and of the effect of SMN depletion during aging. Methods A mild mouse model of SMA, termed Smn2B/−;SMN2+/−, was generated by crossing Smn−/−;SMN2 and Smn2B/2B mice. This new model was characterized using behavioral testing, histology, western blot, muscle-nerve electrophysiology as well as ultrasonography to study classical SMA features and extra-neuronal involvement. Findings Smn2B/−;SMN2+/− mice have normal survival, mild but sustained motor weakness, denervation and neuronal/neuromuscular junction (NMJ) transmission defects, and neurogenic muscle atrophy that are more prominent in male mice. Increased centrally located nuclei, intrinsic contractile and relaxation muscle defects were also identified in both female and male mice, with some male predominance. There was an absence of extra-neuronal pathology. Interpretation The Smn2B/−;SMN2+/− mouse provides a model of mild SMA, displaying some hallmark features including reduced weight, sustained motor weakness, electrophysiological transmission deficit, NMJ defects, and muscle atrophy. Early and prominent increase central nucleation and intrinsic electrophysiological deficits demonstrate the potential role played by muscle in SMA disease. The use of this model will allow for the understanding of the most susceptible pathogenic molecular changes in motor neurons and muscles, investigation of the effects of SMN depletion in aging, sex differences and most importantly will provide guidance for the currently aging SMA patients treated with the recently approved genetic therapies. Funding : This work was supported by Cure SMA/Families of SMA Canada (grant numbers KOT-1819 and KOT-2021); Muscular Dystrophy Association (USA) (grant number 575466); and Canadian Institutes of Health Research (CIHR) (grant number PJT-156379).
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Affiliation(s)
- Marc-Olivier Deguise
- Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, Ontario K1H 8L6, Canada; Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada; Centre for Neuromuscular Disease, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
| | - Yves De Repentigny
- Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, Ontario K1H 8L6, Canada
| | - Alexandra Tierney
- Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, Ontario K1H 8L6, Canada
| | - Ariane Beauvais
- Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, Ontario K1H 8L6, Canada
| | - Jean Michaud
- Department of Pathology and Laboratory Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
| | - Lucia Chehade
- Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, Ontario K1H 8L6, Canada; Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada; Centre for Neuromuscular Disease, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
| | - Mohamed Thabet
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
| | - Brittany Paul
- Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, Ontario K1H 8L6, Canada; Centre for Neuromuscular Disease, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
| | - Aoife Reilly
- Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, Ontario K1H 8L6, Canada; Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada; Centre for Neuromuscular Disease, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
| | - Sabrina Gagnon
- Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, Ontario K1H 8L6, Canada
| | - Jean-Marc Renaud
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada; Centre for Neuromuscular Disease, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
| | - Rashmi Kothary
- Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, Ontario K1H 8L6, Canada; Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada; Centre for Neuromuscular Disease, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada; Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada; Department of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada.
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9
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Šoltić D, Shorrock HK, Allardyce H, Wilson EL, Holt I, Synowsky SA, Shirran SL, Parson SH, Gillingwater TH, Fuller HR. Lamin A/C dysregulation contributes to cardiac pathology in a mouse model of severe spinal muscular atrophy. Hum Mol Genet 2019; 28:3515-3527. [PMID: 31397869 PMCID: PMC6927462 DOI: 10.1093/hmg/ddz195] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 07/25/2019] [Accepted: 07/25/2019] [Indexed: 12/21/2022] Open
Abstract
Cardiac pathology is emerging as a prominent systemic feature of spinal muscular atrophy (SMA), but little is known about the underlying molecular pathways. Using quantitative proteomics analysis, we demonstrate widespread molecular defects in heart tissue from the Taiwanese mouse model of severe SMA. We identify increased levels of lamin A/C as a robust molecular phenotype in the heart of SMA mice and show that lamin A/C dysregulation is also apparent in SMA patient fibroblast cells and other tissues from SMA mice. Lamin A/C expression was regulated in vitro by knockdown of the E1 ubiquitination factor ubiquitin-like modifier activating enzyme 1, a key downstream mediator of SMN-dependent disease pathways, converging on β-catenin signaling. Increased levels of lamin A are known to increase the rigidity of nuclei, inevitably disrupting contractile activity in cardiomyocytes. The increased lamin A/C levels in the hearts of SMA mice therefore provide a likely mechanism explaining morphological and functional cardiac defects, leading to blood pooling. Therapeutic strategies directed at lamin A/C may therefore offer a new approach to target cardiac pathology in SMA.
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Affiliation(s)
- Darija Šoltić
- Institute for Science and Technology in Medicine, Keele University, Keele ST5 5BG, UK
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry SY10 7AG, UK
| | - Hannah K Shorrock
- Edinburgh Medical School: Biomedical Sciences
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Hazel Allardyce
- Institute of Education for Medical and Dental Science, College of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen AB24 3FX, UK
| | - Emma L Wilson
- Chester Medical School, University of Chester, Chester CH1 4BJ, UK
| | - Ian Holt
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry SY10 7AG, UK
| | - Silvia A Synowsky
- BSRC Mass Spectrometry and Proteomics Facility, University of St Andrews, St Andrews KY16 9ST, UK
| | - Sally L Shirran
- BSRC Mass Spectrometry and Proteomics Facility, University of St Andrews, St Andrews KY16 9ST, UK
| | - Simon H Parson
- Institute of Education for Medical and Dental Science, College of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen AB24 3FX, UK
| | - Thomas H Gillingwater
- Edinburgh Medical School: Biomedical Sciences
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Heidi R Fuller
- Institute for Science and Technology in Medicine, Keele University, Keele ST5 5BG, UK
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry SY10 7AG, UK
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10
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Abstract
Autosomal-recessive proximal spinal muscular atrophy (Werdnig-Hoffmann, Kugelberg-Welander) is caused by mutation of the SMN1 gene, and the clinical severity correlates with the number of copies of a nearly identical gene, SMN2. The SMN protein plays a critical role in spliceosome assembly and may have other cellular functions, such as mRNA transport. Cell culture and animal models have helped to define the disease mechanism and to identify targets for therapeutic intervention. The main focus for developing treatment has been to increase SMN levels, and accomplishing this with small molecules, oligonucleotides, and gene replacement has been quite. An oligonucleotide, nusinersen, was recently approved for treatment in patients, and confirmatory studies of other agents are now under way.
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Affiliation(s)
- Eveline S Arnold
- Neurogenetics Branch, National Institutes of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Kenneth H Fischbeck
- Neurogenetics Branch, National Institutes of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States.
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11
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Osman EY, Washington CW, Simon ME, Megiddo D, Greif H, Lorson CL. Analysis of Azithromycin Monohydrate as a Single or a Combinatorial Therapy in a Mouse Model of Severe Spinal Muscular Atrophy. J Neuromuscul Dis 2018; 4:237-249. [PMID: 28598854 DOI: 10.3233/jnd-170230] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is a neurodegenerative autosomal recessive disorder characterized by the loss of α-motor neurons. A variety of molecular pathways are being investigated to elevate SMN protein expression in SMA models and in the clinic. One of these approaches involves stabilizing the SMNΔ7 protein by inducing translational read-through. Previous studies have demonstrated that functionality and stability are partially restored to the otherwise unstable SMNΔ7 by the addition of non-specific C-terminal peptide sequences, or by inducing a similar molecular event through the use of read-through inducing compounds such as aminoglycosides. OBJECTIVE The objective was to determine the efficacy of the macrolide Azithromycin (AZM), an FDA approved read-through-inducing compound, in the well-established severe mouse model of SMA. METHODS Initially, dosing regimen following ICV administrations of AZM at different post-natal days and concentrations was determined by their impact on SMN levels in disease-relevant tissues. Selected dose was then tested for phenotypic parameters changes as compared to the appropriate controls and in conjugation to another therapy. RESULTS AZM increases SMN protein in disease relevant tissues, however, this did not translate into similar improvements in the SMA phenotype in a severe mouse model of SMA. Co-administration of AZM and a previously developed antisense oligonucleotide that increases SMN2 splicing, resulted in an improvement in the SMA phenotype beyond either AZM or ASO alone, including a highly significant extension in survival with improvement in body weight and movement. CONCLUSIONS It is important to explore various approaches for SMA therapeutics, hence compounds that specifically induce SMNΔ7 read-through, without having prohibitive toxicity, may provide an alternative platform for a combinatorial treatment. Here we established that AZM activity at a low dose can increase SMN protein in disease-relevant animal model and can impact disease severity.
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Affiliation(s)
- Erkan Y Osman
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA.,Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | - Charles W Washington
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA.,Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | - Madeline E Simon
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA.,Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | | | | | - Christian L Lorson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA.,Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
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12
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Nonclinical data supporting orphan medicinal product designations: lessons from rare neurological conditions. Drug Discov Today 2018; 23:26-48. [DOI: 10.1016/j.drudis.2017.09.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 09/01/2017] [Accepted: 09/27/2017] [Indexed: 12/14/2022]
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13
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Wijngaarde CA, Blank AC, Stam M, Wadman RI, van den Berg LH, van der Pol WL. Cardiac pathology in spinal muscular atrophy: a systematic review. Orphanet J Rare Dis 2017; 12:67. [PMID: 28399889 PMCID: PMC5387385 DOI: 10.1186/s13023-017-0613-5] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Accepted: 03/14/2017] [Indexed: 01/09/2023] Open
Abstract
Background Hereditary proximal spinal muscular atrophy (SMA) is a severe neuromuscular disease of childhood caused by homozygous loss of function of the survival motor neuron (SMN) 1 gene. The presence of a second, nearly identical SMN gene (SMN2) in the human genome ensures production of residual levels of the ubiquitously expressed SMN protein. Alpha-motor neurons in the ventral horns of the spinal cord are most vulnerable to reduced SMN concentrations but the development or function of other tissues may also be affected, and cardiovascular abnormalities have frequently been reported both in patients and SMA mouse models. Methods We systematically reviewed reported cardiac pathology in relation to SMN deficiency. To investigate the relevance of the possible association in more detail, we used clinical classification systems to characterize structural cardiac defects and arrhythmias. Conclusions Seventy-two studies with a total of 264 SMA patients with reported cardiac pathology were identified, along with 14 publications on SMA mouse models with abnormalities of the heart. Structural cardiac pathology, mainly septal defects and abnormalities of the cardiac outflow tract, was reported predominantly in the most severely affected patients (i.e. SMA type 1). Cardiac rhythm disorders were most frequently reported in patients with milder SMA types (e.g. SMA type 3). All included studies lacked control groups and a standardized approach for cardiac evaluation. The convergence to specific abnormalities of cardiac structure and function may indicate vulnerability of specific cell types or developmental processes relevant for cardiogenesis. Future studies would benefit from a controlled and standardized approach for cardiac evaluation in patients with SMA. Electronic supplementary material The online version of this article (doi:10.1186/s13023-017-0613-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- C A Wijngaarde
- Department of Neurology and Neurosurgery, F02.230, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Heidelberglaan 100, 3508 GA, Utrecht, The Netherlands.
| | - A C Blank
- Department of Pediatric Cardiology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - M Stam
- Department of Neurology and Neurosurgery, F02.230, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Heidelberglaan 100, 3508 GA, Utrecht, The Netherlands
| | - R I Wadman
- Department of Neurology and Neurosurgery, F02.230, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Heidelberglaan 100, 3508 GA, Utrecht, The Netherlands
| | - L H van den Berg
- Department of Neurology and Neurosurgery, F02.230, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Heidelberglaan 100, 3508 GA, Utrecht, The Netherlands
| | - W L van der Pol
- Department of Neurology and Neurosurgery, F02.230, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Heidelberglaan 100, 3508 GA, Utrecht, The Netherlands.
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14
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Calder AN, Androphy EJ, Hodgetts KJ. Small Molecules in Development for the Treatment of Spinal Muscular Atrophy. J Med Chem 2016; 59:10067-10083. [PMID: 27490705 PMCID: PMC5744254 DOI: 10.1021/acs.jmedchem.6b00670] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disease resulting from pathologically low levels of survival motor neuron (SMN) protein. The majority of mRNA from the SMN2 allele undergoes alternative splicing and excludes critical codons, causing an SMN protein deficiency. While there is currently no FDA-approved treatment for SMA, early therapeutic efforts have focused on testing repurposed drugs such as phenylbutyrate (2), valproic acid (3), riluzole (6), hydroxyurea (7), and albuterol (9), none of which has demonstrated clinical effectiveness. More recently, clinical trials have focused on novel small-molecule compounds identified from high-throughput screening and medicinal chemistry optimization such as olesoxime (11), CK-2127107, RG7800, LMI070, and RG3039 (17). In this paper, we review both repurposed drugs and small-molecule compounds discovered following medicinal chemistry optimization for the potential treatment of SMA.
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Affiliation(s)
- Alyssa N. Calder
- Laboratory for Drug Discovery in Neurodegeneration, Brigham & Women’s Hospital and Harvard Medical School, 65 Landsdowne Street, Cambridge, MA 02139, USA
| | - Elliot J. Androphy
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Kevin J. Hodgetts
- Laboratory for Drug Discovery in Neurodegeneration, Brigham & Women’s Hospital and Harvard Medical School, 65 Landsdowne Street, Cambridge, MA 02139, USA
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15
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Osman EY, Washington CW, Kaifer KA, Mazzasette C, Patitucci TN, Florea KM, Simon ME, Ko CP, Ebert AD, Lorson CL. Optimization of Morpholino Antisense Oligonucleotides Targeting the Intronic Repressor Element1 in Spinal Muscular Atrophy. Mol Ther 2016; 24:1592-601. [PMID: 27401142 DOI: 10.1038/mt.2016.145] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 07/04/2016] [Indexed: 12/13/2022] Open
Abstract
Loss of Survival Motor Neuron-1 (SMN1) causes Spinal Muscular Atrophy, a devastating neurodegenerative disease. SMN2 is a nearly identical copy gene; however SMN2 cannot prevent disease development in the absence of SMN1 since the majority of SMN2-derived transcripts are alternatively spliced, encoding a truncated, unstable protein lacking exon 7. Nevertheless, SMN2 retains the ability to produce low levels of functional protein. Previously we have described a splice-switching Morpholino antisense oligonucleotide (ASO) sequence that targets a potent intronic repressor, Element1 (E1), located upstream of SMN2 exon 7. In this study, we have assessed a novel panel of Morpholino ASOs with the goal of optimizing E1 ASO activity. Screening for efficacy in the SMNΔ7 mouse model, a single ASO variant was more active in vivo compared with the original E1(MO)-ASO. Sequence variant eleven (E1(MOv11)) consistently showed greater efficacy by increasing the lifespan of severe Spinal Muscular Atrophy mice after a single intracerebroventricular injection in the central nervous system, exhibited a strong dose-response across an order of magnitude, and demonstrated excellent target engagement by partially reversing the pathogenic SMN2 splicing event. We conclude that Morpholino modified ASOs are effective in modifying SMN2 splicing and have the potential for future Spinal Muscular Atrophy clinical applications.
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Affiliation(s)
- Erkan Y Osman
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA
| | - Charles W Washington
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA
| | - Kevin A Kaifer
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA.,Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, Missouri, USA
| | - Chiara Mazzasette
- Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
| | - Teresa N Patitucci
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Kyra M Florea
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA.,Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, Missouri, USA
| | - Madeline E Simon
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA.,Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, Missouri, USA
| | - Chien-Ping Ko
- Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
| | - Allison D Ebert
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Christian L Lorson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA.,Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, Missouri, USA
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16
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Chali F, Desseille C, Houdebine L, Benoit E, Rouquet T, Bariohay B, Lopes P, Branchu J, Della Gaspera B, Pariset C, Chanoine C, Charbonnier F, Biondi O. Long-term exercise-specific neuroprotection in spinal muscular atrophy-like mice. J Physiol 2016; 594:1931-52. [PMID: 26915343 DOI: 10.1113/jp271361] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 12/22/2015] [Indexed: 01/15/2023] Open
Abstract
KEY POINTS The real impact of physical exercise parameters, i.e. intensity, type of contraction and solicited energetic metabolism, on neuroprotection in the specific context of neurodegeneration remains poorly explored. In this study behavioural, biochemical and cellular analyses were conducted to compare the effects of two different long-term exercise protocols, high intensity swimming and low intensity running, on motor units of a type 3 spinal muscular atrophy (SMA)-like mouse model. Our data revealed a preferential SMA-induced death of intermediate and fast motor neurons which was limited by the swimming protocol only, suggesting a close relationship between neuron-specific protection and their activation levels by specific exercise. The exercise-induced neuroprotection was independent of SMN protein expression and associated with specific metabolic and behavioural adaptations with notably a swimming-induced reduction of muscle fatigability. Our results provide new insight into the motor units' adaptations to different physical exercise parameters and will contribute to the design of new active physiotherapy protocols for patient care. ABSTRACT Spinal muscular atrophy (SMA) is a group of autosomal recessive neurodegenerative diseases differing in their clinical outcome, characterized by the specific loss of spinal motor neurons, caused by insufficient level of expression of the protein survival of motor neuron (SMN). No cure is at present available for SMA. While physical exercise might represent a promising approach for alleviating SMA symptoms, the lack of data dealing with the effects of different exercise types on diseased motor units still precludes the use of active physiotherapy in SMA patients. In the present study, we have evaluated the efficiency of two long-term physical exercise paradigms, based on either high intensity swimming or low intensity running, in alleviating SMA symptoms in a mild type 3 SMA-like mouse model. We found that 10 months' physical training induced significant benefits in terms of resistance to muscle damage, energetic metabolism, muscle fatigue and motor behaviour. Both exercise types significantly enhanced motor neuron survival, independently of SMN expression, leading to the maintenance of neuromuscular junctions and skeletal muscle phenotypes, particularly in the soleus, plantaris and tibialis of trained mice. Most importantly, both exercises significantly improved neuromuscular excitability properties. Further, all these training-induced benefits were quantitatively and qualitatively related to the specific characteristics of each exercise, suggesting that the related neuroprotection is strongly dependent on the specific activation of some motor neuron subpopulations. Taken together, the present data show significant long-term exercise benefits in type 3 SMA-like mice providing important clues for designing rehabilitation programmes in patients.
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Affiliation(s)
- Farah Chali
- Université Paris Descartes and INSERM UMRS 1124, 45 rue des Saints-Pères, F-75270, Paris Cedex 06, France
| | - Céline Desseille
- Université Paris Descartes and INSERM UMRS 1124, 45 rue des Saints-Pères, F-75270, Paris Cedex 06, France
| | - Léo Houdebine
- Université Paris Descartes and INSERM UMRS 1124, 45 rue des Saints-Pères, F-75270, Paris Cedex 06, France
| | - Evelyne Benoit
- Institut des Neurosciences Paris-Saclay UMR 9197, CNRS, Bât 32-33, and Service d'Ingénierie Moléculaire des Protéines (DSV/iBiTec-S/SIMOPRO), CEA de Saclay, Bât. 152, 91190, Gif-sur-Yvette, France
| | - Thaïs Rouquet
- BIOMEOSTASIS, Nutritional behavior and metabolic disorders, FST St Jérôme, Service B52, Avenue Escadrille Normandie-Niemen, 13397, Marseille, France
| | - Bruno Bariohay
- BIOMEOSTASIS, Nutritional behavior and metabolic disorders, FST St Jérôme, Service B52, Avenue Escadrille Normandie-Niemen, 13397, Marseille, France
| | - Philippe Lopes
- Université Paris Descartes and INSERM UMRS 1124, 45 rue des Saints-Pères, F-75270, Paris Cedex 06, France.,Université d'Evry-val-d'Essonne, Bd F. Mitterrand, 91000, Evry, France
| | - Julien Branchu
- Université Paris Descartes and INSERM UMRS 1124, 45 rue des Saints-Pères, F-75270, Paris Cedex 06, France
| | - Bruno Della Gaspera
- Université Paris Descartes and INSERM UMRS 1124, 45 rue des Saints-Pères, F-75270, Paris Cedex 06, France
| | - Claude Pariset
- Université Paris Descartes and INSERM UMRS 1124, 45 rue des Saints-Pères, F-75270, Paris Cedex 06, France
| | - Christophe Chanoine
- Université Paris Descartes and INSERM UMRS 1124, 45 rue des Saints-Pères, F-75270, Paris Cedex 06, France
| | - Frédéric Charbonnier
- Université Paris Descartes and INSERM UMRS 1124, 45 rue des Saints-Pères, F-75270, Paris Cedex 06, France
| | - Olivier Biondi
- Université Paris Descartes and INSERM UMRS 1124, 45 rue des Saints-Pères, F-75270, Paris Cedex 06, France
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17
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Zhou H, Meng J, Marrosu E, Janghra N, Morgan J, Muntoni F. Repeated low doses of morpholino antisense oligomer: an intermediate mouse model of spinal muscular atrophy to explore the window of therapeutic response. Hum Mol Genet 2015; 24:6265-77. [PMID: 26264577 PMCID: PMC4614699 DOI: 10.1093/hmg/ddv329] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 07/20/2015] [Accepted: 08/06/2015] [Indexed: 11/14/2022] Open
Abstract
The human SMN2 transgenic mice are well-established models of spinal muscular atrophy (SMA). While the severe type I mouse model has a rapidly progressive condition mimicking type I SMA in humans, the mild type III mice do not faithfully recapitulate chronic SMA variants affecting children. A SMA mouse model that clinically mimics the features of type II and III SMA in human is therefore needed. In this study, we generated intermediately affected SMA mice by delivering low-dose morpholino oligomer (PMO25) into the existing severe SMA mice. We show that a single low-dose administration of PMO25 moderately extended the survival of severe type I SMA mice. The neuromuscular pathology is also modestly but significantly improved in these mice. A second administration of PMO25 at postnatal day 5 (PND5) demonstrated an additive effect on survival. Additional systemic administration of low-dose PMO25 at 2-week intervals suppressed the occurrence of distal necrosis beyond postnatal day 100, and induced more complete phenotypic rescue than a single bolus high-dose injection at PND0. Our study demonstrates that survival of motor neuron (SMN) is required early at a critical threshold to prevent symptoms and suggests that subsequent systemic administration of low-dose PMO25 in SMA mice can provide therapeutic benefit and phenotypic rescue, presumably via peripheral SMN restoration. Our work also provides additional insight into the time window of response to administration of antisense oligonucleotides to SMA mice with an intermediate phenotype. This information is crucial at a time when a number of therapeutic interventions are in clinical trials in SMA patients.
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Affiliation(s)
- Haiyan Zhou
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK
| | - Jinhong Meng
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK
| | - Elena Marrosu
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK
| | - Narinder Janghra
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK
| | - Jennifer Morgan
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK
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18
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Systemic, postsymptomatic antisense oligonucleotide rescues motor unit maturation delay in a new mouse model for type II/III spinal muscular atrophy. Proc Natl Acad Sci U S A 2015; 112:E5863-72. [PMID: 26460027 DOI: 10.1073/pnas.1509758112] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Clinical presentation of spinal muscular atrophy (SMA) ranges from a neonatal-onset, very severe disease to an adult-onset, milder form. SMA is caused by the mutation of the Survival Motor Neuron 1 (SMN1) gene, and prognosis inversely correlates with the number of copies of the SMN2 gene, a human-specific homolog of SMN1. Despite progress in identifying potential therapies for the treatment of SMA, many questions remain including how late after onset treatments can still be effective and what the target tissues should be. These questions can be addressed in part with preclinical animal models; however, modeling the array of SMA severities in the mouse, which lacks SMN2, has proven challenging. We created a new mouse model for the intermediate forms of SMA presenting with a delay in neuromuscular junction maturation and a decrease in the number of functional motor units, all relevant to the clinical presentation of the disease. Using this new model, in combination with clinical electrophysiology methods, we found that administering systemically SMN-restoring antisense oligonucleotides (ASOs) at the age of onset can extend survival and rescue the neurological phenotypes. Furthermore, these effects were also achieved by administration of the ASOs late after onset, independent of the restoration of SMN in the spinal cord. Thus, by adding to the limited repertoire of existing mouse models for type II/III SMA, we demonstrate that ASO therapy can be effective even when administered after onset of the neurological symptoms, in young adult mice, and without being delivered into the central nervous system.
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19
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Swiderski K, Lynch GS. Therapeutic potential of orphan drugs for the rare skeletal muscle diseases. Expert Opin Orphan Drugs 2015. [DOI: 10.1517/21678707.2015.1085858] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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20
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Cherry JJ, Kobayashi DT, Lynes MM, Naryshkin NN, Tiziano FD, Zaworski PG, Rubin LL, Jarecki J. Assays for the identification and prioritization of drug candidates for spinal muscular atrophy. Assay Drug Dev Technol 2015; 12:315-41. [PMID: 25147906 DOI: 10.1089/adt.2014.587] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive genetic disorder resulting in degeneration of α-motor neurons of the anterior horn and proximal muscle weakness. It is the leading cause of genetic mortality in children younger than 2 years. It affects ∼1 in 11,000 live births. In 95% of cases, SMA is caused by homozygous deletion of the SMN1 gene. In addition, all patients possess at least one copy of an almost identical gene called SMN2. A single point mutation in exon 7 of the SMN2 gene results in the production of low levels of full-length survival of motor neuron (SMN) protein at amounts insufficient to compensate for the loss of the SMN1 gene. Although no drug treatments are available for SMA, a number of drug discovery and development programs are ongoing, with several currently in clinical trials. This review describes the assays used to identify candidate drugs for SMA that modulate SMN2 gene expression by various means. Specifically, it discusses the use of high-throughput screening to identify candidate molecules from primary screens, as well as the technical aspects of a number of widely used secondary assays to assess SMN messenger ribonucleic acid (mRNA) and protein expression, localization, and function. Finally, it describes the process of iterative drug optimization utilized during preclinical SMA drug development to identify clinical candidates for testing in human clinical trials.
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21
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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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22
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SMN is required for the maintenance of embryonic stem cells and neuronal differentiation in mice. Brain Struct Funct 2014; 220:1539-53. [PMID: 24633826 DOI: 10.1007/s00429-014-0743-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 02/28/2014] [Indexed: 01/02/2023]
Abstract
Survival motor neuron (SMN) is the determining factor in spinal muscular atrophy, the most common genetic cause of childhood mortality. We have previously found that SMN regulates stem cell division, proliferation and differentiation in Drosophila. However, it is unknown whether a similar effect exists in vertebrates. Here, we show that SMN is enriched in highly proliferative embryonic stem cells (ESCs) in mice and reduction of SMN impairs the pluripotency of ESCs. Moreover, we find that SMN reduction activates ERK signaling and affects neuronal differentiation in vitro. Teratomas with reduced SMN grow more slowly and show weaker signals of neuronal differentiation than those with a normal level of SMN. Finally, we show that over-expression of SMN is protective for ESCs from retinoic acid-induced differentiation. Taken together, our results suggest that SMN plays a role in the maintenance of pluripotent ESCs and neuronal differentiation in mice.
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23
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Sleigh JN, Burgess RW, Gillingwater TH, Cader MZ. Morphological analysis of neuromuscular junction development and degeneration in rodent lumbrical muscles. J Neurosci Methods 2014; 227:159-65. [PMID: 24530702 DOI: 10.1016/j.jneumeth.2014.02.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 02/04/2014] [Accepted: 02/05/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND The neuromuscular junction (NMJ) is a specialised synapse formed between a lower motor neuron and a skeletal muscle fibre, and is an early pathological target in numerous nervous system disorders, including amyotrophic lateral sclerosis (ALS), Charcot-Marie-Tooth disease (CMT), and spinal muscular atrophy (SMA). Being able to accurately visualise and quantitatively characterise the NMJ in rodent models of neurological conditions, particularly during the early stages of disease, is thus of clear importance. NEW METHOD We present a method for dissection of rodent deep lumbrical muscles located in the hind-paw, and describe how to perform immunofluorescent morphological analysis of their NMJs. RESULTS These techniques allow the temporal assessment of a number of developmental and pathological NMJ phenotypes in lumbrical muscles. COMPARISON WITH EXISTING METHODS Small muscles, such as the distal hind-limb lumbrical muscles, possess a major advantage over larger muscles, such as gastrocnemius, in that they can be whole-mounted and the entire innervation pattern visualised. This reduces preparation time and ambiguity when evaluating important neuromuscular phenotypes. CONCLUSIONS Together, these methods will allow the reader to perform a detailed and accurate analysis of the neuromuscular system in rodent models of disease in order to identify pertinent features of neuropathology.
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Affiliation(s)
- James N Sleigh
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK; The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | | | - Thomas H Gillingwater
- Centre for Integrative Physiology & Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - M Zameel Cader
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK; The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK.
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24
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Boyer JG, Ferrier A, Kothary R. More than a bystander: the contributions of intrinsic skeletal muscle defects in motor neuron diseases. Front Physiol 2013; 4:356. [PMID: 24391590 PMCID: PMC3866803 DOI: 10.3389/fphys.2013.00356] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 11/20/2013] [Indexed: 12/13/2022] Open
Abstract
Spinal muscular atrophy (SMA), amyotrophic lateral sclerosis (ALS), and spinal-bulbar muscular atrophy (SBMA) are devastating diseases characterized by the degeneration of motor neurons. Although the molecular causes underlying these diseases differ, recent findings have highlighted the contribution of intrinsic skeletal muscle defects in motor neuron diseases. The use of cell culture and animal models has led to the important finding that muscle defects occur prior to and independently of motor neuron degeneration in motor neuron diseases. In SMA for instance, the muscle specific requirements of the SMA disease-causing gene have been demonstrated by a series of genetic rescue experiments in SMA models. Conditional ALS mouse models expressing a muscle specific mutant SOD1 gene develop atrophy and muscle degeneration in the absence of motor neuron pathology. Treating SBMA mice by over-expressing IGF-1 in a skeletal muscle-specific manner attenuates disease severity and improves motor neuron pathology. In the present review, we provide an in depth description of muscle intrinsic defects, and discuss how they impact muscle function in these diseases. Furthermore, we discuss muscle-specific therapeutic strategies used to treat animal models of SMA, ALS, and SBMA. The study of intrinsic skeletal muscle defects is crucial for the understanding of the pathophysiology of these diseases and will open new therapeutic options for the treatment of motor neuron diseases.
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Affiliation(s)
- Justin G Boyer
- Ottawa Hospital Research Institute, Regenerative Medicine Program Ottawa ON, Canada ; Department of Cellular and Molecular Medicine, University of Ottawa Ottawa, ON, Canada
| | - Andrew Ferrier
- Ottawa Hospital Research Institute, Regenerative Medicine Program Ottawa ON, Canada ; Department of Cellular and Molecular Medicine, University of Ottawa Ottawa, ON, Canada
| | - Rashmi Kothary
- Ottawa Hospital Research Institute, Regenerative Medicine Program Ottawa ON, Canada ; Department of Cellular and Molecular Medicine, University of Ottawa Ottawa, ON, Canada ; Department of Medicine, University of Ottawa Ottawa, ON, Canada
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Lutz CM, Osborne MA. Optimizing mouse models of neurodegenerative disorders: are therapeutics in sight? FUTURE NEUROLOGY 2013; 9:67-75. [PMID: 29479291 DOI: 10.2217/fnl.13.66] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The genomic and biologic conservation between mice and humans, along with our increasing ability to manipulate the mouse genome, places the mouse as a premier model for deciphering disease mechanisms and testing potential new therapies. Despite these advantages, mouse models of neurodegenerative disease are sometimes difficult to generate and can present challenges that must be carefully addressed when used for preclinical studies. For those models that do exist, the standardization and optimization of the models is a critical step in ensuring success in both basic research and preclinical use. This review looks back on the history of model development for neurodegenerative diseases and highlights the key strategies that have been learned in order to improve the design, development and use of mouse models in the study of neurodegenerative disease.
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Affiliation(s)
- Cathleen M Lutz
- The Jackson Laboratory, Genetic Resource Sciences, 600 Main Street, Bar Harbor, ME 04609, USA
| | - Melissa A Osborne
- The Jackson Laboratory, Genetic Resource Sciences, 600 Main Street, Bar Harbor, ME 04609, USA
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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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