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Xie Q, Chen X, Ma H, Zhu Y, Ma Y, Jalinous L, Cox GF, Weaver F, Yang J, Kennedy Z, Gruntman A, Du A, Su Q, He R, Tai PW, Gao G, Xie J. Improved gene therapy for spinal muscular atrophy in mice using codon-optimized hSMN1 transgene and hSMN1 gene-derived promotor. EMBO Mol Med 2024; 16:945-965. [PMID: 38413838 PMCID: PMC11018631 DOI: 10.1038/s44321-024-00037-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/31/2024] [Accepted: 02/01/2024] [Indexed: 02/29/2024] Open
Abstract
Physiological regulation of transgene expression is a major challenge in gene therapy. Onasemnogene abeparvovec (Zolgensma®) is an approved adeno-associated virus (AAV) vector gene therapy for infants with spinal muscular atrophy (SMA), however, adverse events have been observed in both animals and patients following treatment. The construct contains a native human survival motor neuron 1 (hSMN1) transgene driven by a strong, cytomegalovirus enhancer/chicken β-actin (CMVen/CB) promoter providing high, ubiquitous tissue expression of SMN. We developed a second-generation AAV9 gene therapy expressing a codon-optimized hSMN1 transgene driven by a promoter derived from the native hSMN1 gene. This vector restored SMN expression close to physiological levels in the central nervous system and major systemic organs of a severe SMA mouse model. In a head-to-head comparison between the second-generation vector and a benchmark vector, identical in design to onasemnogene abeparvovec, the 2nd-generation vector showed better safety and improved efficacy in SMA mouse model.
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Affiliation(s)
- Qing Xie
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, MA, USA
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, USA
| | - Xiupeng Chen
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, MA, USA
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, USA
| | - Hong Ma
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, MA, USA
- Viral Vector Core, UMass Chan Medical School, Worcester, MA, USA
| | | | - Yijie Ma
- CANbridge Pharmaceuticals, Burlington, MA, USA
| | | | | | | | - Jun Yang
- CANbridge Pharmaceuticals, Burlington, MA, USA
| | | | - Alisha Gruntman
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, MA, USA
- Pediatrics, UMass Chan Medical School, Worcester, MA, USA
| | - Ailing Du
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, MA, USA
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, USA
| | - Qin Su
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, MA, USA
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, USA
- Viral Vector Core, UMass Chan Medical School, Worcester, MA, USA
| | - Ran He
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, MA, USA
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, USA
- Viral Vector Core, UMass Chan Medical School, Worcester, MA, USA
| | - Phillip Wl Tai
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, MA, USA
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, USA
- Li Weibo Institute for Rare Diseases Research, UMass Chan Medical School, Worcester, MA, USA
| | - Guangping Gao
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, MA, USA.
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, USA.
- Li Weibo Institute for Rare Diseases Research, UMass Chan Medical School, Worcester, MA, USA.
| | - Jun Xie
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, MA, USA.
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, USA.
- Viral Vector Core, UMass Chan Medical School, Worcester, MA, USA.
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Lapp HS, Freigang M, Hagenacker T, Weiler M, Wurster CD, Günther R. Biomarkers in 5q-associated spinal muscular atrophy-a narrative review. J Neurol 2023; 270:4157-4178. [PMID: 37289324 PMCID: PMC10421827 DOI: 10.1007/s00415-023-11787-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 05/15/2023] [Accepted: 05/16/2023] [Indexed: 06/09/2023]
Abstract
5q-associated spinal muscular atrophy (SMA) is a rare genetic disease caused by mutations in the SMN1 gene, resulting in a loss of functional SMN protein and consecutive degeneration of motor neurons in the ventral horn. The disease is clinically characterized by proximal paralysis and secondary skeletal muscle atrophy. New disease-modifying drugs driving SMN gene expression have been developed in the past decade and have revolutionized SMA treatment. The rise of treatment options led to a concomitant need of biomarkers for therapeutic guidance and an improved disease monitoring. Intensive efforts have been undertaken to develop suitable markers, and numerous candidate biomarkers for diagnostic, prognostic, and predictive values have been identified. The most promising markers include appliance-based measures such as electrophysiological and imaging-based indices as well as molecular markers including SMN-related proteins and markers of neurodegeneration and skeletal muscle integrity. However, none of the proposed biomarkers have been validated for the clinical routine yet. In this narrative review, we discuss the most promising candidate biomarkers for SMA and expand the discussion by addressing the largely unfolded potential of muscle integrity markers, especially in the context of upcoming muscle-targeting therapies. While the discussed candidate biomarkers hold potential as either diagnostic (e.g., SMN-related biomarkers), prognostic (e.g., markers of neurodegeneration, imaging-based markers), predictive (e.g., electrophysiological markers) or response markers (e.g., muscle integrity markers), no single measure seems to be suitable to cover all biomarker categories. Hence, a combination of different biomarkers and clinical assessments appears to be the most expedient solution at the time.
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Affiliation(s)
- H S Lapp
- Department of Neurology, University Hospital Carl Gustav Carus at TU Dresden, Fetscherstraße 74, 01307, Dresden, Germany
| | - M Freigang
- Department of Neurology, University Hospital Carl Gustav Carus at TU Dresden, Fetscherstraße 74, 01307, Dresden, Germany
| | - T Hagenacker
- Department of Neurology and Center for Translational Neuro- and Behavioral Science (C-TNBS), University Medicine Essen, Essen, Germany
| | - M Weiler
- Department of Neurology, Heidelberg University Hospital, Heidelberg, Germany
| | - C D Wurster
- Department of Neurology, University Hospital Ulm, Ulm, Germany
- German Center for Neurodegenerative Diseases (DZNE) Ulm, Ulm, Germany
| | - René Günther
- Department of Neurology, University Hospital Carl Gustav Carus at TU Dresden, Fetscherstraße 74, 01307, Dresden, Germany.
- German Center for Neurodegenerative Diseases (DZNE) Dresden, Dresden, Germany.
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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: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Lumpkin CJ, Harris AW, Connell AJ, Kirk RW, Whiting JA, Saieva L, Pellizzoni L, Burghes AHM, Butchbach MER. Evaluation of the orally bioavailable 4-phenylbutyrate-tethered trichostatin A analogue AR42 in models of spinal muscular atrophy. Sci Rep 2023; 13:10374. [PMID: 37365234 PMCID: PMC10293174 DOI: 10.1038/s41598-023-37496-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 06/22/2023] [Indexed: 06/28/2023] Open
Abstract
Proximal spinal muscular atrophy (SMA) is a leading genetic cause for infant death in the world and results from the selective loss of motor neurons in the spinal cord. SMA is a consequence of low levels of SMN protein and small molecules that can increase SMN expression are of considerable interest as potential therapeutics. Previous studies have shown that both 4-phenylbutyrate (4PBA) and trichostatin A (TSA) increase SMN expression in dermal fibroblasts derived from SMA patients. AR42 is a 4PBA-tethered TSA derivative that is a very potent histone deacetylase inhibitor. SMA patient fibroblasts were treated with either AR42, AR19 (a related analogue), 4PBA, TSA or vehicle for 5 days and then immunostained for SMN localization. AR42 as well as 4PBA and TSA increased the number of SMN-positive nuclear gems in a dose-dependent manner while AR19 did not show marked changes in gem numbers. While gem number was increased in AR42-treated SMA fibroblasts, there were no significant changes in FL-SMN mRNA or SMN protein. The neuroprotective effect of this compound was then assessed in SMNΔ7 SMA (SMN2+/+;SMNΔ7+/+;mSmn-/-) mice. Oral administration of AR42 prior to disease onset increased the average lifespan of SMNΔ7 SMA mice by ~ 27% (20.1 ± 1.6 days for AR42-treated mice vs. 15.8 ± 0.4 days for vehicle-treated mice). AR42 treatment also improved motor function in these mice. AR42 treatment inhibited histone deacetylase (HDAC) activity in treated spinal cord although it did not affect SMN protein expression in these mice. AKT and GSK3β phosphorylation were both significantly increased in SMNΔ7 SMA mouse spinal cords. In conclusion, presymptomatic administration of the HDAC inhibitor AR42 ameliorates the disease phenotype in SMNΔ7 SMA mice in a SMN-independent manner possibly by increasing AKT neuroprotective signaling.
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Affiliation(s)
- Casey J Lumpkin
- Division of Neurology, Nemours Children's Hospital Delaware, 4462 E400 DuPont Experimental Station, 200 Powder Mill Road, Wilmington, DE, 19803, USA
- Department of Biological Sciences, University of Delaware, Newark, DE, USA
| | - Ashlee W Harris
- Division of Neurology, Nemours Children's Hospital Delaware, 4462 E400 DuPont Experimental Station, 200 Powder Mill Road, Wilmington, DE, 19803, USA
| | - Andrew J Connell
- Division of Neurology, Nemours Children's Hospital Delaware, 4462 E400 DuPont Experimental Station, 200 Powder Mill Road, Wilmington, DE, 19803, USA
| | - Ryan W Kirk
- Division of Neurology, Nemours Children's Hospital Delaware, 4462 E400 DuPont Experimental Station, 200 Powder Mill Road, Wilmington, DE, 19803, USA
| | - Joshua A Whiting
- Division of Neurology, Nemours Children's Hospital Delaware, 4462 E400 DuPont Experimental Station, 200 Powder Mill Road, Wilmington, DE, 19803, USA
| | - Luciano Saieva
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Livio Pellizzoni
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
- Department of Neurology, Columbia University, New York, NY, USA
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, USA
| | - Arthur H M Burghes
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
- Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Matthew E R Butchbach
- Division of Neurology, Nemours Children's Hospital Delaware, 4462 E400 DuPont Experimental Station, 200 Powder Mill Road, Wilmington, DE, 19803, USA.
- Department of Biological Sciences, University of Delaware, Newark, DE, USA.
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
- Department of Pediatrics, Thomas Jefferson University, Philadelphia, PA, USA.
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Brown SJ, Kline RA, Synowsky SA, Shirran SL, Holt I, Sillence KA, Claus P, Wirth B, Wishart TM, Fuller HR. The Proteome Signatures of Fibroblasts from Patients with Severe, Intermediate and Mild Spinal Muscular Atrophy Show Limited Overlap. Cells 2022; 11:cells11172624. [PMID: 36078032 PMCID: PMC9454632 DOI: 10.3390/cells11172624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 08/17/2022] [Accepted: 08/18/2022] [Indexed: 12/04/2022] Open
Abstract
Most research to characterise the molecular consequences of spinal muscular atrophy (SMA) has focused on SMA I. Here, proteomic profiling of skin fibroblasts from severe (SMA I), intermediate (SMA II), and mild (SMA III) patients, alongside age-matched controls, was conducted using SWATH mass spectrometry analysis. Differentially expressed proteomic profiles showed limited overlap across each SMA type, and variability was greatest within SMA II fibroblasts, which was not explained by SMN2 copy number. Despite limited proteomic overlap, enriched canonical pathways common to two of three SMA severities with at least one differentially expressed protein from the third included mTOR signalling, regulation of eIF2 and eIF4 signalling, and protein ubiquitination. Network expression clustering analysis identified protein profiles that may discriminate or correlate with SMA severity. From these clusters, the differential expression of PYGB (SMA I), RAB3B (SMA II), and IMP1 and STAT1 (SMA III) was verified by Western blot. All SMA fibroblasts were transfected with an SMN-enhanced construct, but only RAB3B expression in SMA II fibroblasts demonstrated an SMN-dependent response. The diverse proteomic profiles and pathways identified here pave the way for studies to determine their utility as biomarkers for patient stratification or monitoring treatment efficacy and for the identification of severity-specific treatments.
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Affiliation(s)
- Sharon J. Brown
- School of Pharmacy and Bioengineering (PhaB), Keele University, Keele ST5 5BG, UK
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry SY10 7AG, UK
| | - Rachel A. Kline
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian EH25 9RG, UK
- Euan MacDonald Centre, University of Edinburgh, Edinburgh EH16 4SB, 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
| | - Ian Holt
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry SY10 7AG, UK
| | | | - Peter Claus
- SMATHERIA gGmbH—Non-Profit Biomedical Research Institute, 30625 Hannover, Germany
| | - Brunhilde Wirth
- Institute of Human Genetics, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
- Center for Rare Diseases, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany
- Institute for Genetics, University of Cologne, 50931 Cologne, Germany
| | - Thomas M. Wishart
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian EH25 9RG, UK
- Euan MacDonald Centre, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Heidi R. Fuller
- School of Pharmacy and Bioengineering (PhaB), Keele University, Keele ST5 5BG, UK
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry SY10 7AG, UK
- Correspondence: ; Tel.: +44-(0)1-782-734546
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Buettner JM, Sime Longang JK, Gerstner F, Apel KS, Blanco-Redondo B, Sowoidnich L, Janzen E, Langenhan T, Wirth B, Simon CM. Central synaptopathy is the most conserved feature of motor circuit pathology across spinal muscular atrophy mouse models. iScience 2021; 24:103376. [PMID: 34825141 PMCID: PMC8605199 DOI: 10.1016/j.isci.2021.103376] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 10/12/2021] [Accepted: 10/26/2021] [Indexed: 11/04/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disease caused by reduced survival motor neuron (SMN) protein. Recently, SMN dysfunction has been linked to individual aspects of motor circuit pathology in a severe SMA mouse model. To determine whether these disease mechanisms are conserved, we directly compared the motor circuit pathology of three SMA mouse models. The severe SMNΔ7 model exhibits vast motor circuit defects, including degeneration of motor neurons, spinal excitatory synapses, and neuromuscular junctions (NMJs). In contrast, the Taiwanese model shows very mild motor neuron pathology, but early central synaptic loss. In the intermediate Smn2B/- model, strong pathology of central excitatory synapses and NMJs precedes the late onset of p53-dependent motor neuron death. These pathological events correlate with SMN-dependent splicing dysregulation of specific mRNAs. Our study provides a knowledge base for properly tailoring future studies and identifies central excitatory synaptopathy as a key feature of motor circuit pathology in SMA. Comparison of detailed motor circuit pathology across three SMA mouse models Motor circuit pathology correlates with dysregulation of specific mRNAs Motor neuron death in severe and intermediate SMA models is p53-dependent Central excitatory synaptopathy is the most conserved feature of SMA pathology
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Affiliation(s)
- Jannik M Buettner
- Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig 04103, Germany
| | | | - Florian Gerstner
- Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig 04103, Germany
| | - Katharina S Apel
- Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig 04103, Germany
| | - Beatriz Blanco-Redondo
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig 04103, Germany
| | - Leonie Sowoidnich
- Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig 04103, Germany
| | - Eva Janzen
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Tobias Langenhan
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig 04103, Germany
| | - Brunhilde Wirth
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany.,Center for Rare Diseases Cologne, University Hospital of Cologne, Cologne, Germany
| | - Christian M Simon
- Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig 04103, Germany
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Allardyce H, Kuhn D, Hernandez-Gerez E, Hensel N, Huang YT, Faller K, Gillingwater TH, Quondamatteo F, Claus P, Parson SH. Renal pathology in a mouse model of severe Spinal Muscular Atrophy is associated with downregulation of Glial Cell-Line Derived Neurotrophic Factor (GDNF). Hum Mol Genet 2021; 29:2365-2378. [PMID: 32588893 DOI: 10.1093/hmg/ddaa126] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 06/11/2020] [Accepted: 06/12/2020] [Indexed: 12/16/2022] Open
Abstract
Spinal muscular atrophy (SMA) occurs as a result of cell-ubiquitous depletion of the essential survival motor neuron (SMN) protein. Characteristic disease pathology is driven by a particular vulnerability of the ventral motor neurons of the spinal cord to decreased SMN. Perhaps not surprisingly, many other organ systems are also impacted by SMN depletion. The normal kidney expresses very high levels of SMN protein, equivalent to those found in the nervous system and liver, and levels are dramatically lowered by ~90-95% in mouse models of SMA. Taken together, these data suggest that renal pathology may be present in SMA. We have addressed this using an established mouse model of severe SMA. Nephron number, as assessed by gold standard stereological techniques, was significantly reduced. In addition, morphological assessment showed decreased renal vasculature, particularly of the glomerular capillary knot, dysregulation of nephrin and collagen IV, and ultrastructural changes in the trilaminar filtration layers of the nephron. To explore the molecular drivers underpinning this process, we correlated these findings with quantitative PCR measurements and protein analyses of glial cell-line-derived neurotrophic factor, a crucial factor in ureteric bud branching and subsequent nephron development. Glial cell-line-derived neurotrophic factor levels were significantly reduced at early stages of disease in SMA mice. Collectively, these findings reveal significant renal pathology in a mouse model of severe SMA, further reinforcing the need to develop and administer systemic therapies for this neuromuscular disease.
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Affiliation(s)
- Hazel Allardyce
- Institute of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen AB25 2ZD, UK.,Euan Macdonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Daniela Kuhn
- Hannover Medical School, Institute of Neuroanatomy and Cell Biology, Hannover 30625, Germany
| | - Elena Hernandez-Gerez
- Institute of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen AB25 2ZD, UK.,Euan Macdonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Niko Hensel
- Hannover Medical School, Institute of Neuroanatomy and Cell Biology, Hannover 30625, Germany.,Center for Systems Neuroscience (ZSN) Hannover, University of Veterinary Medicine Hannover, Hannover 30559, Germany
| | - Yu-Ting Huang
- Euan Macdonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH16 4SB, UK.,Edinburgh Medical School: Biomedical Sciences, College of Medicine & Veterinary Medicine, University of Edinburgh, Edinburgh EH8 9AG, UK
| | - Kiterie Faller
- Euan Macdonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH16 4SB, UK.,Edinburgh Medical School: Biomedical Sciences, College of Medicine & Veterinary Medicine, University of Edinburgh, Edinburgh EH8 9AG, UK
| | - Thomas H Gillingwater
- Euan Macdonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH16 4SB, UK.,Edinburgh Medical School: Biomedical Sciences, College of Medicine & Veterinary Medicine, University of Edinburgh, Edinburgh EH8 9AG, UK
| | - Fabio Quondamatteo
- Anatomy Facility, School of Life Sciences, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK
| | - Peter Claus
- Hannover Medical School, Institute of Neuroanatomy and Cell Biology, Hannover 30625, Germany.,Center for Systems Neuroscience (ZSN) Hannover, University of Veterinary Medicine Hannover, Hannover 30559, Germany
| | - Simon H Parson
- Institute of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen AB25 2ZD, UK.,Euan Macdonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH16 4SB, UK
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Deguise MO, Chehade L, Kothary R. Metabolic Dysfunction in Spinal Muscular Atrophy. Int J Mol Sci 2021; 22:5913. [PMID: 34072857 DOI: 10.3390/ijms22115913] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 05/25/2021] [Accepted: 05/29/2021] [Indexed: 12/11/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive genetic disorder leading to paralysis, muscle atrophy, and death. Significant advances in antisense oligonucleotide treatment and gene therapy have made it possible for SMA patients to benefit from improvements in many aspects of the once devastating natural history of the disease. How the depletion of survival motor neuron (SMN) protein, the product of the gene implicated in the disease, leads to the consequent pathogenic changes remains unresolved. Over the past few years, evidence toward a potential contribution of gastrointestinal, metabolic, and endocrine defects to disease phenotype has surfaced. These findings ranged from disrupted body composition, gastrointestinal tract, fatty acid, glucose, amino acid, and hormonal regulation. Together, these changes could have a meaningful clinical impact on disease traits. However, it is currently unclear whether these findings are secondary to widespread denervation or unique to the SMA phenotype. This review provides an in-depth account of metabolism-related research available to date, with a discussion of unique features compared to other motor neuron and related disorders.
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Ojala KS, Reedich EJ, DiDonato CJ, Meriney SD. In Search of a Cure: The Development of Therapeutics to Alter the Progression of Spinal Muscular Atrophy. Brain Sci 2021; 11:194. [PMID: 33562482 DOI: 10.3390/brainsci11020194] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/29/2021] [Accepted: 02/01/2021] [Indexed: 12/19/2022] Open
Abstract
Until the recent development of disease-modifying therapeutics, spinal muscular atrophy (SMA) was considered a devastating neuromuscular disease with a poor prognosis for most affected individuals. Symptoms generally present during early childhood and manifest as muscle weakness and progressive paralysis, severely compromising the affected individual’s quality of life, independence, and lifespan. SMA is most commonly caused by the inheritance of homozygously deleted SMN1 alleles with retention of one or more copies of a paralog gene, SMN2, which inversely correlates with disease severity. The recent advent and use of genetically targeted therapies have transformed SMA into a prototype for monogenic disease treatment in the era of genetic medicine. Many SMA-affected individuals receiving these therapies achieve traditionally unobtainable motor milestones and survival rates as medicines drastically alter the natural progression of this disease. This review discusses historical SMA progression and underlying disease mechanisms, highlights advances made in therapeutic research, clinical trials, and FDA-approved medicines, and discusses possible second-generation and complementary medicines as well as optimal temporal intervention windows in order to optimize motor function and improve quality of life for all SMA-affected individuals.
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Singh NN, Hoffman S, Reddi PP, Singh RN. Spinal muscular atrophy: Broad disease spectrum and sex-specific phenotypes. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166063. [PMID: 33412266 DOI: 10.1016/j.bbadis.2020.166063] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/14/2020] [Accepted: 12/21/2020] [Indexed: 12/17/2022]
Abstract
Spinal muscular atrophy (SMA) is one of the major genetic disorders associated with infant mortality. More than 90% of cases of SMA result from deletions of or mutations in the Survival Motor Neuron 1 (SMN1) gene. SMN2, a nearly identical copy of SMN1, does not compensate for the loss of SMN1 due to predominant skipping of exon 7. The spectrum of SMA is broad, ranging from prenatal death to infant mortality to survival into adulthood. All tissues, including brain, spinal cord, bone, skeletal muscle, heart, lung, liver, pancreas, gastrointestinal tract, kidney, spleen, ovary and testis, are directly and/or indirectly affected in SMA. Accumulating evidence on impaired mitochondrial biogenesis and defects in X chromosome-linked modifying factors, coupled with the sexual dimorphic nature of many tissues, point to sex-specific vulnerabilities in SMA. Here we review the role of sex in the pathogenesis of SMA.
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Li YJ, Chen TH, Wu YZ, Tseng YH. Metabolic and Nutritional Issues Associated with Spinal Muscular Atrophy. Nutrients 2020; 12:nu12123842. [PMID: 33339220 PMCID: PMC7766651 DOI: 10.3390/nu12123842] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/02/2020] [Accepted: 12/15/2020] [Indexed: 12/12/2022] Open
Abstract
Spinal muscular atrophy (SMA), the main genetic cause of infant death, is a neurodegenerative disease characterized by the selective loss of motor neurons in the anterior horn of the spinal cord, accompanied by muscle wasting. Pathomechanically, SMA is caused by low levels of the survival motor neuron protein (SMN) resulting from the loss of the SMN1 gene. However, emerging research extends the pathogenic effect of SMN deficiency beyond motor neurons. A variety of metabolic abnormalities, especially altered fatty acid metabolism and impaired glucose tolerance, has been described in isolated cases of SMA; therefore, the impact of SMN deficiency in metabolic abnormalities has been speculated. Although the life expectancy of these patients has increased due to novel disease-modifying therapies and standardization of care, understanding of the involvement of metabolism and nutrition in SMA is still limited. Optimal nutrition support and metabolic monitoring are essential for patients with SMA, and a comprehensive nutritional assessment can guide personalized nutritional therapy for this vulnerable population. It has recently been suggested that metabolomics studies before and after the onset of SMA in patients can provide valuable information about the direct or indirect effects of SMN deficiency on metabolic abnormalities. Furthermore, identifying and quantifying the specific metabolites in SMA patients may serve as an authentic biomarker or therapeutic target for SMA. Here, we review the main epidemiological and mechanistic findings that link metabolic changes to SMA and further discuss the principles of metabolomics as a novel approach to seek biomarkers and therapeutic insights in SMA.
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Affiliation(s)
- Yang-Jean Li
- Department of Pediatrics, Kaohsiung Municipal United Hospital, Kaohsiung 80455, Taiwan;
| | - Tai-Heng Chen
- Department of Pediatrics, Division of Pediatric Emergency, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; (Y.-Z.W.); (Y.-H.T.)
- School of Post-Baccalaureate Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Correspondence: ; Tel.: +886-7-312-1101; Fax: +886-7-321-2062
| | - Yan-Zhang Wu
- Department of Pediatrics, Division of Pediatric Emergency, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; (Y.-Z.W.); (Y.-H.T.)
| | - Yung-Hao Tseng
- Department of Pediatrics, Division of Pediatric Emergency, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; (Y.-Z.W.); (Y.-H.T.)
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Singh NN, Ottesen EW, Singh RN. A survey of transcripts generated by spinal muscular atrophy genes. Biochim Biophys Acta Gene Regul Mech 2020; 1863:194562. [PMID: 32387331 PMCID: PMC7302838 DOI: 10.1016/j.bbagrm.2020.194562] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 04/01/2020] [Accepted: 04/13/2020] [Indexed: 02/07/2023]
Abstract
Human Survival Motor Neuron (SMN) genes code for SMN, an essential multifunctional protein. Complete loss of SMN is embryonic lethal, while low levels of SMN lead to spinal muscular atrophy (SMA), a major genetic disease of children and infants. Reduced levels of SMN are associated with the abnormal development of heart, lung, muscle, gastro-intestinal system and testis. The SMN loci have been shown to generate a vast repertoire of transcripts, including linear, back- and trans-spliced RNAs as well as antisense long noncoding RNAs. However, functions of the majority of these transcripts remain unknown. Here we review the nature of RNAs generated from the SMN loci and discuss their potential functions in cellular metabolism.
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Affiliation(s)
- Natalia N Singh
- Department of Biomedical Science, Iowa State University, Ames, IA, 50011, United States of America
| | - Eric W Ottesen
- Department of Biomedical Science, Iowa State University, Ames, IA, 50011, United States of America
| | - Ravindra N Singh
- Department of Biomedical Science, Iowa State University, Ames, IA, 50011, United States of America.
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Chen TH. 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. [PMID: 32392694 PMCID: PMC7246502 DOI: 10.3390/ijms21093297] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [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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Wadman RI, van der Pol WL, Bosboom WMJ, Asselman F, van den Berg LH, Iannaccone ST, Vrancken AFJE. Drug treatment for spinal muscular atrophy types II and III. Cochrane Database Syst Rev 2020; 1:CD006282. [PMID: 32006461 PMCID: PMC6995983 DOI: 10.1002/14651858.cd006282.pub5] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is caused by a homozygous deletion of the survival motor neuron 1 (SMN1) gene on chromosome 5, or a heterozygous deletion in combination with a (point) mutation in the second SMN1 allele. This results in degeneration of anterior horn cells, which leads to progressive muscle weakness. Children with SMA type II do not develop the ability to walk without support and have a shortened life expectancy, whereas children with SMA type III develop the ability to walk and have a normal life expectancy. This is an update of a review first published in 2009 and previously updated in 2011. OBJECTIVES To evaluate if drug treatment is able to slow or arrest the disease progression of SMA types II and III, and to assess if such therapy can be given safely. SEARCH METHODS We searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, and ISI Web of Science conference proceedings in October 2018. In October 2018, we also searched two trials registries to identify unpublished trials. SELECTION CRITERIA We sought all randomised or quasi-randomised trials that examined the efficacy of drug treatment for SMA types II and III. Participants had to fulfil the clinical criteria and have a homozygous deletion or hemizygous deletion in combination with a point mutation in the second allele of the SMN1 gene (5q11.2-13.2) confirmed by genetic analysis. The primary outcome measure was change in disability score within one year after the onset of treatment. Secondary outcome measures within one year after the onset of treatment were change in muscle strength, ability to stand or walk, change in quality of life, time from the start of treatment until death or full-time ventilation and adverse events attributable to treatment during the trial period. Treatment strategies involving SMN1-replacement with viral vectors are out of the scope of this review, but a summary is given in Appendix 1. Drug treatment for SMA type I is the topic of a separate Cochrane Review. DATA COLLECTION AND ANALYSIS We followed standard Cochrane methodology. MAIN RESULTS The review authors found 10 randomised, placebo-controlled trials of treatments for SMA types II and III for inclusion in this review, with 717 participants. We added four of the trials at this update. The trials investigated creatine (55 participants), gabapentin (84 participants), hydroxyurea (57 participants), nusinersen (126 participants), olesoxime (165 participants), phenylbutyrate (107 participants), somatotropin (20 participants), thyrotropin-releasing hormone (TRH) (nine participants), valproic acid (33 participants), and combination therapy with valproic acid and acetyl-L-carnitine (ALC) (61 participants). Treatment duration was from three to 24 months. None of the studies investigated the same treatment and none was completely free of bias. All studies had adequate blinding, sequence generation and reporting of primary outcomes. Based on moderate-certainty evidence, intrathecal nusinersen improved motor function (disability) in children with SMA type II, with a 3.7-point improvement in the nusinersen group on the Hammersmith Functional Motor Scale Expanded (HFMSE; range of possible scores 0 to 66), compared to a 1.9-point decline on the HFMSE in the sham procedure group (P < 0.01; n = 126). On all motor function scales used, higher scores indicate better function. Based on moderate-certainty evidence from two studies, the following interventions had no clinically important effect on motor function scores in SMA types II or III (or both) in comparison to placebo: creatine (median change 1 higher, 95% confidence interval (CI) -1 to 2; on the Gross Motor Function Measure (GMFM), scale 0 to 264; n = 40); and combination therapy with valproic acid and carnitine (mean difference (MD) 0.64, 95% CI -1.1 to 2.38; on the Modified Hammersmith Functional Motor Scale (MHFMS), scale 0 to 40; n = 61). Based on low-certainty evidence from other single studies, the following interventions had no clinically important effect on motor function scores in SMA types II or III (or both) in comparison to placebo: gabapentin (median change 0 in the gabapentin group and -2 in the placebo group on the SMA Functional Rating Scale (SMAFRS), scale 0 to 50; n = 66); hydroxyurea (MD -1.88, 95% CI -3.89 to 0.13 on the GMFM, scale 0 to 264; n = 57), phenylbutyrate (MD -0.13, 95% CI -0.84 to 0.58 on the Hammersmith Functional Motor Scale (HFMS) scale 0 to 40; n = 90) and monotherapy of valproic acid (MD 0.06, 95% CI -1.32 to 1.44 on SMAFRS, scale 0 to 50; n = 31). Very low-certainty evidence suggested that the following interventions had little or no effect on motor function: olesoxime (MD 2, 95% -0.25 to 4.25 on the Motor Function Measure (MFM) D1 + D2, scale 0 to 75; n = 160) and somatotropin (median change at 3 months 0.25 higher, 95% CI -1 to 2.5 on the HFMSE, scale 0 to 66; n = 19). One small TRH trial did not report effects on motor function and the certainty of evidence for other outcomes from this trial were low or very low. Results of nine completed trials investigating 4-aminopyridine, acetyl-L-carnitine, CK-2127107, hydroxyurea, pyridostigmine, riluzole, RO6885247/RG7800, salbutamol and valproic acid were awaited and not available for analysis at the time of writing. Various trials and studies investigating treatment strategies other than nusinersen (e.g. SMN2-augmentation by small molecules), are currently ongoing. AUTHORS' CONCLUSIONS Nusinersen improves motor function in SMA type II, based on moderate-certainty evidence. Creatine, gabapentin, hydroxyurea, phenylbutyrate, valproic acid and the combination of valproic acid and ALC probably have no clinically important effect on motor function in SMA types II or III (or both) based on low-certainty evidence, and olesoxime and somatropin may also have little to no clinically important effect but evidence was of very low-certainty. One trial of TRH did not measure motor function.
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Affiliation(s)
- Renske I Wadman
- University Medical Center Utrecht, Brain Center Rudolf MagnusDepartment of NeurologyHeidelberglaan 100UtrechtNetherlands3584 CX
| | - W Ludo van der Pol
- University Medical Center Utrecht, Brain Center Rudolf MagnusDepartment of NeurologyHeidelberglaan 100UtrechtNetherlands3584 CX
| | - Wendy MJ Bosboom
- Onze Lieve Vrouwe Gasthuis locatie WestDepartment of NeurologyAmsterdamNetherlands
| | - Fay‐Lynn Asselman
- University Medical Center Utrecht, Brain Center Rudolf MagnusDepartment of NeurologyHeidelberglaan 100UtrechtNetherlands3584 CX
| | - Leonard H van den Berg
- University Medical Center Utrecht, Brain Center Rudolf MagnusDepartment of NeurologyHeidelberglaan 100UtrechtNetherlands3584 CX
| | - Susan T Iannaccone
- University of Texas Southwestern Medical CenterDepartment of Pediatrics5323 Harry Hines BoulevardDallasTexasUSA75390
| | - Alexander FJE Vrancken
- University Medical Center Utrecht, Brain Center Rudolf MagnusDepartment of NeurologyHeidelberglaan 100UtrechtNetherlands3584 CX
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Abstract
BACKGROUND Spinal muscular atrophy (SMA) is caused by a homozygous deletion of the survival motor neuron 1 (SMN1) gene on chromosome 5, or a heterozygous deletion in combination with a point mutation in the second SMN1 allele. This results in degeneration of anterior horn cells, which leads to progressive muscle weakness. By definition, children with SMA type I are never able to sit without support and usually die or become ventilator dependent before the age of two years. There have until very recently been no drug treatments to influence the course of SMA. We undertook this updated review to evaluate new evidence on emerging treatments for SMA type I. The review was first published in 2009 and previously updated in 2011. OBJECTIVES To assess the efficacy and safety of any drug therapy designed to slow or arrest progression of spinal muscular atrophy (SMA) type I. SEARCH METHODS We searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, and ISI Web of Science conference proceedings in October 2018. We also searched two trials registries to identify unpublished trials (October 2018). SELECTION CRITERIA We sought all randomised controlled trials (RCTs) or quasi-RCTs that examined the efficacy of drug treatment for SMA type I. Included participants had to fulfil clinical criteria and have a genetically confirmed deletion or mutation of the SMN1 gene (5q11.2-13.2). The primary outcome measure was age at death or full-time ventilation. Secondary outcome measures were acquisition of motor milestones, i.e. head control, rolling, sitting or standing, motor milestone response on disability scores within one year after the onset of treatment, and adverse events and serious adverse events attributable to treatment during the trial period. Treatment strategies involving SMN1 gene replacement with viral vectors are out of the scope of this review. DATA COLLECTION AND ANALYSIS We followed standard Cochrane methodology. MAIN RESULTS We identified two RCTs: one trial of intrathecal nusinersen in comparison to a sham (control) procedure in 121 randomised infants with SMA type I, which was newly included at this update, and one small trial comparing riluzole treatment to placebo in 10 children with SMA type I. The RCT of intrathecally-injected nusinersen was stopped early for efficacy (based on a predefined Hammersmith Infant Neurological Examination-Section 2 (HINE-2) response). At the interim analyses after 183 days of treatment, 41% (21/51) of nusinersen-treated infants showed a predefined improvement on HINE-2, compared to 0% (0/27) of participants in the control group. This trial was largely at low risk of bias. Final analyses (ranging from 6 months to 13 months of treatment), showed that fewer participants died or required full-time ventilation (defined as more than 16 hours daily for 21 days or more) in the nusinersen-treated group than the control group (hazard ratio (HR) 0.53, 95% confidence interval (CI) 0.32 to 0.89; N = 121; a 47% lower risk; moderate-certainty evidence). A proportion of infants in the nusinersen group and none of 37 infants in the control group achieved motor milestones: 37/73 nusinersen-treated infants (51%) achieved a motor milestone response on HINE-2 (risk ratio (RR) 38.51, 95% CI 2.43 to 610.14; N = 110; moderate-certainty evidence); 16/73 achieved head control (RR 16.95, 95% CI 1.04 to 274.84; moderate-certainty evidence); 6/73 achieved independent sitting (RR 6.68, 95% CI 0.39 to 115.38; moderate-certainty evidence); 7/73 achieved rolling over (RR 7.70, 95% CI 0.45 to 131.29); and 1/73 achieved standing (RR 1.54, 95% CI 0.06 to 36.92; moderate-certainty evidence). Seventy-one per cent of nusinersen-treated infants versus 3% of infants in the control group were responders on the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND) measure of motor disability (RR 26.36, 95% CI 3.79 to 183.18; N = 110; moderate-certainty evidence). Adverse events and serious adverse events occurred in the majority of infants but were no more frequent in the nusinersen-treated group than the control group (RR 0.99, 95% CI 0.92 to 1.05 and RR 0.70, 95% CI 0.55 to 0.89, respectively; N = 121; moderate-certainty evidence). In the riluzole trial, three of seven children treated with riluzole were still alive at the ages of 30, 48, and 64 months, whereas all three children in the placebo group died. None of the children in the riluzole or placebo group developed the ability to sit, which was the only milestone reported. There were no adverse effects. The certainty of the evidence for all measured outcomes from this study was very low, because the study was too small to detect or rule out an effect, and had serious limitations, including baseline differences. This trial was stopped prematurely because the pharmaceutical company withdrew funding. Various trials and studies investigating treatment strategies other than nusinersen, such as SMN2 augmentation by small molecules, are ongoing. AUTHORS' CONCLUSIONS Based on the very limited evidence currently available regarding drug treatments for SMA type 1, intrathecal nusinersen probably prolongs ventilation-free and overall survival in infants with SMA type I. It is also probable that a greater proportion of infants treated with nusinersen than with a sham procedure achieve motor milestones and can be classed as responders to treatment on clinical assessments (HINE-2 and CHOP INTEND). The proportion of children experiencing adverse events and serious adverse events on nusinersen is no higher with nusinersen treatment than with a sham procedure, based on evidence of moderate certainty. It is uncertain whether riluzole has any effect in patients with SMA type I, based on the limited available evidence. Future trials could provide more high-certainty, longer-term evidence to confirm this result, or focus on comparing new treatments to nusinersen or evaluate them as an add-on therapy to nusinersen.
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Affiliation(s)
- Renske I Wadman
- University Medical Center Utrecht, Brain Center Rudolf MagnusDepartment of NeurologyHeidelberglaan 100UtrechtNetherlands3584 CX
| | - W Ludo van der Pol
- University Medical Center Utrecht, Brain Center Rudolf MagnusDepartment of NeurologyHeidelberglaan 100UtrechtNetherlands3584 CX
| | - Wendy MJ Bosboom
- Onze Lieve Vrouwe Gasthuis locatie WestDepartment of NeurologyAmsterdamNetherlands
| | - Fay‐Lynn Asselman
- University Medical Center Utrecht, Brain Center Rudolf MagnusDepartment of NeurologyHeidelberglaan 100UtrechtNetherlands3584 CX
| | - Leonard H van den Berg
- University Medical Center Utrecht, Brain Center Rudolf MagnusDepartment of NeurologyHeidelberglaan 100UtrechtNetherlands3584 CX
| | - Susan T Iannaccone
- University of Texas Southwestern Medical CenterDepartment of Pediatrics5323 Harry Hines BoulevardDallasTexasUSA75390
| | - Alexander FJE Vrancken
- University Medical Center Utrecht, Brain Center Rudolf MagnusDepartment of NeurologyHeidelberglaan 100UtrechtNetherlands3584 CX
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Janzen E, Mendoza-Ferreira N, Hosseinibarkooie S, Schneider S, Hupperich K, Tschanz T, Grysko V, Riessland M, Hammerschmidt M, Rigo F, Bennett CF, Kye MJ, Torres-Benito L, Wirth B. CHP1 reduction ameliorates spinal muscular atrophy pathology by restoring calcineurin activity and endocytosis. Brain 2019; 141:2343-2361. [PMID: 29961886 PMCID: PMC6061875 DOI: 10.1093/brain/awy167] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Accepted: 04/26/2018] [Indexed: 12/12/2022] Open
Abstract
Autosomal recessive spinal muscular atrophy (SMA), the leading genetic cause of infant lethality, is caused by homozygous loss of the survival motor neuron 1 (SMN1) gene. SMA disease severity inversely correlates with the number of SMN2 copies, which in contrast to SMN1, mainly produce aberrantly spliced transcripts. Recently, the first SMA therapy based on antisense oligonucleotides correcting SMN2 splicing, namely SPINRAZATM, has been approved. Nevertheless, in type I SMA-affected individuals—representing 60% of SMA patients—the elevated SMN level may still be insufficient to restore motor neuron function lifelong. Plastin 3 (PLS3) and neurocalcin delta (NCALD) are two SMN-independent protective modifiers identified in humans and proved to be effective across various SMA animal models. Both PLS3 overexpression and NCALD downregulation protect against SMA by restoring impaired endocytosis; however, the exact mechanism of this protection is largely unknown. Here, we identified calcineurin-like EF-hand protein 1 (CHP1) as a novel PLS3 interacting protein using a yeast-two-hybrid screen. Co-immunoprecipitation and pull-down assays confirmed a direct interaction between CHP1 and PLS3. Although CHP1 is ubiquitously present, it is particularly abundant in the central nervous system and at SMA-relevant sites including motor neuron growth cones and neuromuscular junctions. Strikingly, we found elevated CHP1 levels in SMA mice. Congruently, CHP1 downregulation restored impaired axonal growth in Smn-depleted NSC34 motor neuron-like cells, SMA zebrafish and primary murine SMA motor neurons. Most importantly, subcutaneous injection of low-dose SMN antisense oligonucleotide in pre-symptomatic mice doubled the survival rate of severely-affected SMA mice, while additional CHP1 reduction by genetic modification prolonged survival further by 1.6-fold. Moreover, CHP1 reduction further ameliorated SMA disease hallmarks including electrophysiological defects, smaller neuromuscular junction size, impaired maturity of neuromuscular junctions and smaller muscle fibre size compared to low-dose SMN antisense oligonucleotide alone. In NSC34 cells, Chp1 knockdown tripled macropinocytosis whereas clathrin-mediated endocytosis remained unaffected. Importantly, Chp1 knockdown restored macropinocytosis in Smn-depleted cells by elevating calcineurin phosphatase activity. CHP1 is an inhibitor of calcineurin, which collectively dephosphorylates proteins involved in endocytosis, and is therefore crucial in synaptic vesicle endocytosis. Indeed, we found marked hyperphosphorylation of dynamin 1 in SMA motor neurons, which was restored to control level by the heterozygous Chp1 mutant allele. Taken together, we show that CHP1 is a novel SMA modifier that directly interacts with PLS3, and that CHP1 reduction ameliorates SMA pathology by counteracting impaired endocytosis. Most importantly, we demonstrate that CHP1 reduction is a promising SMN-independent therapeutic target for a combinatorial SMA therapy.
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Affiliation(s)
- Eva Janzen
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Natalia Mendoza-Ferreira
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Seyyedmohsen Hosseinibarkooie
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Svenja Schneider
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Kristina Hupperich
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Theresa Tschanz
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Vanessa Grysko
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Markus Riessland
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany.,Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, USA
| | - Matthias Hammerschmidt
- Institute for Zoology, Developmental Biology, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | | | | | - Min Jeong Kye
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Laura Torres-Benito
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Brunhilde Wirth
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany.,Center for Rare Diseases Cologne, University Hospital of Cologne, Cologne, Germany
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Wan B, Feng P, Guan Z, Sheng L, Liu Z, Hua Y. A severe mouse model of spinal muscular atrophy develops early systemic inflammation. Hum Mol Genet 2019; 27:4061-4076. [PMID: 30137324 DOI: 10.1093/hmg/ddy300] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 08/14/2018] [Indexed: 01/17/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a fatal genetic disease, mainly affecting children. A number of recent studies show, aside from lower motor neuron degeneration and atrophy of skeletal muscles, widespread defects present in the central nervous system (CNS) and peripheral non-neuronal cell types of SMA patients and mouse models, particularly of severe forms. However, molecular mechanisms underlying the multi-organ manifestations of SMA were hardly understood. Here, using histology, flow cytometry and gene expression analysis in both messenger RNA and protein levels in various tissues, we found that a severe SMA mouse model develops systemic inflammation in early symptomatic stages. SMA mice had an enhanced intestinal permeability, resulting in microbial invasion into the circulatory system. Expression of proinflammatory cytokines was increased in all tissues and the acute phase response in the liver was activated. Systemic inflammation further mobilized glucocorticoid signaling and in turn led to dysregulation of a large set of genes, including robust upregulation of FAM107A in the spinal cord, increased expression of which has been implicated in neurodegeneration. Moreover, we show that lipopolysaccharide challenge markedly suppressed survival of motor neuron 2 exon 7 splicing in all examined peripheral and CNS tissues, resulting in global survival of motor neuron level reduction. Therefore, we identified a novel pathological mechanism in a severe SMA mouse model, which affects phenotypic severity through multiple paths and should contribute to progression of broad neuronal and non-neuronal defects.
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Affiliation(s)
- Bo Wan
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, Hospital of Soochow University, Suzhou, Jiangsu, China.,Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, China
| | - Pengchao Feng
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, Hospital of Soochow University, Suzhou, Jiangsu, China.,Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, China
| | - Zeyuan Guan
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, Hospital of Soochow University, Suzhou, Jiangsu, China.,Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, China
| | - Lei Sheng
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, Hospital of Soochow University, Suzhou, Jiangsu, China.,Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, China
| | - Zhiyong Liu
- School for Radiological and Interdisciplinary Sciences (RAD-X), Soochow University, Suzhou, Jiangsu, China.,Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, Jiangsu, China
| | - Yimin Hua
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, Hospital of Soochow University, Suzhou, Jiangsu, China.,Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, China
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18
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Lipnick SL, Agniel DM, Aggarwal R, Makhortova NR, Finlayson SG, Brocato A, Palmer N, Darras BT, Kohane I, Rubin LL. Systemic nature of spinal muscular atrophy revealed by studying insurance claims. PLoS One 2019; 14:e0213680. [PMID: 30870495 PMCID: PMC6417721 DOI: 10.1371/journal.pone.0213680] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 02/26/2019] [Indexed: 12/27/2022] Open
Abstract
Objective We investigated the presence of non-neuromuscular phenotypes in patients affected by Spinal Muscular Atrophy (SMA), a disorder caused by a mutation in the Survival of Motor Neuron (SMN) gene, and whether these phenotypes may be clinically detectable prior to clinical signs of neuromuscular degeneration and therefore independent of muscle weakness. Methods We utilized a de-identified database of insurance claims to explore the health of 1,038 SMA patients compared to controls. Two analyses were performed: (1) claims from the entire insurance coverage window; and (2) for SMA patients, claims prior to diagnosis of any neuromuscular disease or evidence of major neuromuscular degeneration to increase the chance that phenotypes could be attributed directly to reduced SMN levels. Logistic regression was used to determine whether phenotypes were diagnosed at significantly different rates between SMA patients and controls and to obtain covariate-adjusted odds ratios. Results Results from the entire coverage window revealed a broad spectrum of phenotypes that are differentially diagnosed in SMA subjects compared to controls. Moreover, data from SMA patients prior to their first clinical signs of neuromuscular degeneration revealed numerous non-neuromuscular phenotypes including defects within the cardiovascular, gastrointestinal, metabolic, reproductive, and skeletal systems. Furthermore, our data provide evidence of a potential ordering of disease progression beginning with these non-neuromuscular phenotypes. Conclusions Our data point to a direct relationship between early, detectable non-neuromuscular symptoms and SMN deficiency. Our findings are particularly important for evaluating the efficacy of SMN-increasing therapies for SMA, comparing the effectiveness of local versus systemically delivered therapeutics, and determining the optimal therapeutic treatment window prior to irreversible neuromuscular damage.
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Affiliation(s)
- Scott L. Lipnick
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts, United States of America
- Department of Biomedical Informatics, Harvard Medical School, Boston, Massachusetts, United States of America
- Center for Assessment Technology & Continuous Health (CATCH), Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Denis M. Agniel
- Department of Biomedical Informatics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Rahul Aggarwal
- Department of Biomedical Informatics, Harvard Medical School, Boston, Massachusetts, United States of America
- Center for Assessment Technology & Continuous Health (CATCH), Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Nina R. Makhortova
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts, United States of America
- Boston Children’s Hospital, Boston, Massachusetts, United States of America
| | - Samuel G. Finlayson
- Department of Biomedical Informatics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Alexandra Brocato
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Nathan Palmer
- Department of Biomedical Informatics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Basil T. Darras
- Boston Children’s Hospital, Boston, Massachusetts, United States of America
| | - Isaac Kohane
- Department of Biomedical Informatics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Lee L. Rubin
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts, United States of America
- Harvard Stem Cell Institute, Cambridge, Massachusetts, United States of America
- * E-mail:
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19
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Sheng L, Wan B, Feng P, Sun J, Rigo F, Bennett CF, Akerman M, Krainer AR, Hua Y. Downregulation of Survivin contributes to cell-cycle arrest during postnatal cardiac development in a severe spinal muscular atrophy mouse model. Hum Mol Genet 2019; 27:486-498. [PMID: 29220503 DOI: 10.1093/hmg/ddx418] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 11/28/2017] [Indexed: 11/13/2022] Open
Abstract
Spinal muscular atrophy (SMA) is the leading genetic cause of infant mortality, characterized by progressive degeneration of spinal-cord motor neurons, leading to atrophy of skeletal muscles. However, accumulating evidence indicates that it is a multi-system disorder, particularly in its severe forms. Several studies delineated structural and functional cardiac abnormalities in SMA patients and mouse models, yet the abnormalities have been primarily attributed to autonomic dysfunction. Here, we show in a severe mouse model that its cardiomyocytes undergo G0/G1 cell-cycle arrest and enhanced apoptosis during postnatal development. Microarray and real-time RT-PCR analyses revealed that a set of genes associated with cell cycle and apoptosis were dysregulated in newborn pups. Of particular interest, the Birc5 gene, which encodes Survivin, an essential protein for heart development, was down-regulated even on pre-symptomatic postnatal day 0. Interestingly, cultured cardiomyocytes depleted of SMN recapitulated the gene expression changes including downregulation of Survivin and abnormal cell-cycle progression; and overexpression of Survivin rescued the cell-cycle defect. Finally, increasing SMN in SMA mice with a therapeutic antisense oligonucleotide improved heart pathology and recovered expression of deregulated genes. Collectively, our data demonstrate that the cardiac malfunction of the severe SMA mouse model is mainly a cell-autonomous defect, caused by widespread gene deregulation in heart tissue, particularly of Birc5, resulting in developmental abnormalities through cell-cycle arrest and apoptosis.
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Affiliation(s)
- Lei Sheng
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, China.,Institute of Neuroscience, Soochow University, Suzhou, Jiangsu 215123, China
| | - Bo Wan
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, China.,Institute of Neuroscience, Soochow University, Suzhou, Jiangsu 215123, China
| | - Pengchao Feng
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, China.,Institute of Neuroscience, Soochow University, Suzhou, Jiangsu 215123, China
| | - Junjie Sun
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, China.,Institute of Neuroscience, Soochow University, Suzhou, Jiangsu 215123, China
| | - Frank Rigo
- Ionis Pharmaceuticals, Carlsbad, CA 92010, USA
| | | | - Martin Akerman
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, NY 11724, USA.,Envisagenics, Inc., New York, NY 10017, USA
| | - Adrian R Krainer
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, NY 11724, USA
| | - Yimin Hua
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, China.,Institute of Neuroscience, Soochow University, Suzhou, Jiangsu 215123, China
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20
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Walter LM, Koch CE, Betts CA, Ahlskog N, Meijboom KE, van Westering TLE, Hazell G, Bhomra A, Claus P, Oster H, Wood MJA, Bowerman M. Light modulation ameliorates expression of circadian genes and disease progression in spinal muscular atrophy mice. Hum Mol Genet 2018; 27:3582-3597. [PMID: 29982483 PMCID: PMC6168969 DOI: 10.1093/hmg/ddy249] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 05/31/2018] [Accepted: 06/29/2018] [Indexed: 12/21/2022] Open
Abstract
Physiology and behaviour are critically dependent on circadian regulation via a core set of clock genes, dysregulation of which leads to metabolic and sleep disturbances. Metabolic and sleep perturbations occur in spinal muscular atrophy (SMA), a neuromuscular disorder caused by loss of the survival motor neuron (SMN) protein and characterized by motor neuron loss and muscle atrophy. We therefore investigated the expression of circadian rhythm genes in various metabolic tissues and spinal cord of the Taiwanese Smn-/-;SMN2 SMA animal model. We demonstrate a dysregulated expression of the core clock genes (clock, ARNTL/Bmal1, Cry1/2, Per1/2) and clock output genes (Nr1d1 and Dbp) in SMA tissues during disease progression. We also uncover an age- and tissue-dependent diurnal expression of the Smn gene. Importantly, we observe molecular and phenotypic corrections in SMA mice following direct light modulation. Our study identifies a key relationship between an SMA pathology and peripheral core clock gene dysregulation, highlights the influence of SMN on peripheral circadian regulation and metabolism and has significant implications for the development of peripheral therapeutic approaches and clinical care management of SMA patients.
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Affiliation(s)
- Lisa M Walter
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany
| | | | - Corinne A Betts
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Nina Ahlskog
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Katharina E Meijboom
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | | | - Gareth Hazell
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Amarjit Bhomra
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Peter Claus
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany
| | - Henrik Oster
- Institute of Neurobiology, University of Lübeck, Lübeck, Germany
| | - Matthew J A Wood
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Melissa Bowerman
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
- Current affiliations: School of Medicine, Keele University, Staffordshire, UK
- Institute for Science and Technology in Medicine, Stoke-on-Trent, UK
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, UK
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21
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Maxwell GK, Szunyogova E, Shorrock HK, Gillingwater TH, Parson SH. Developmental and degenerative cardiac defects in the Taiwanese mouse model of severe spinal muscular atrophy. J Anat 2018; 232:965-978. [PMID: 29473159 PMCID: PMC5978979 DOI: 10.1111/joa.12793] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/17/2018] [Indexed: 12/31/2022] Open
Abstract
Spinal muscular atrophy (SMA), an autosomal recessive disease caused by a decrease in levels of the survival motor neuron (SMN) protein, is the most common genetic cause of infant mortality. Although neuromuscular pathology is the most severe feature of SMA, other organs and tissues, including the heart, are also known to be affected in both patients and animal models. Here, we provide new insights into changes occurring in the heart, predominantly at pre- and early symptomatic ages, in the Taiwanese mouse model of severe SMA. Thinning of the interventricular septum and dilation of the ventricles occurred at pre- and early symptomatic ages. However, the left ventricular wall was significantly thinner in SMA mice from birth, occurring prior to any overt neuromuscular symptoms. Alterations in collagen IV protein from birth indicated changes to the basement membrane and contributed to the abnormal arrangement of cardiomyocytes in SMA hearts. This raises the possibility that developmental defects, occurring prenatally, may contribute to cardiac pathology in SMA. In addition, cardiomyocytes in SMA hearts exhibited oxidative stress at pre-symptomatic ages and increased apoptosis during early symptomatic stages of disease. Heart microvasculature was similarly decreased at an early symptomatic age, likely contributing to the oxidative stress and apoptosis phenotypes observed. Finally, an increased incidence of blood retention in SMA hearts post-fixation suggests the likelihood of functional defects, resulting in blood pooling. These pathologies mirror dilated cardiomyopathy, with clear consequences for heart function that would likely contribute to potential heart failure. Our findings add significant additional experimental evidence in support of the requirement to develop systemic therapies for SMA capable of treating non-neuromuscular pathologies.
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Affiliation(s)
| | - Eva Szunyogova
- Institute for Medical ScienceUniversity of AberdeenAberdeenUK
- Euan MacDonald Centre for Motor Neurone Disease ResearchUniversity of EdinburghEdinburghUK
| | - Hannah K. Shorrock
- Euan MacDonald Centre for Motor Neurone Disease ResearchUniversity of EdinburghEdinburghUK
- Edinburgh Medical School: Biomedical SciencesUniversity of EdinburghEdinburghUK
| | - Thomas H. Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease ResearchUniversity of EdinburghEdinburghUK
- Edinburgh Medical School: Biomedical SciencesUniversity of EdinburghEdinburghUK
| | - Simon H. Parson
- Institute for Medical ScienceUniversity of AberdeenAberdeenUK
- Euan MacDonald Centre for Motor Neurone Disease ResearchUniversity of EdinburghEdinburghUK
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22
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Wood MJA, Talbot K, Bowerman M. Spinal muscular atrophy: antisense oligonucleotide therapy opens the door to an integrated therapeutic landscape. Hum Mol Genet 2018; 26:R151-R159. [PMID: 28977438 DOI: 10.1093/hmg/ddx215] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 06/02/2017] [Indexed: 01/03/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a devastating neuromuscular disorder characterized by loss of spinal cord motor neurons, muscle atrophy and infantile death or severe disability. It is caused by severe reduction of the ubiquitously expressed survival motor neuron (SMN) protein, owing to loss of the SMN1 gene. This would be completely incompatible with survival without the presence of a quasi-identical duplicated gene, SMN2, specific to humans. SMN2 harbours a silent point mutation that favours the production of transcripts lacking exon 7 and a rapidly degraded non-functional SMNΔ7 protein, but from which functional full length SMN protein is produced at very low levels (∼10%). Since the seminal discovery of the SMA-causing gene in 1995, research has focused on the development of various SMN replacement strategies culminating, in December 2016, in the approval of the first precise molecularly targeted therapy for SMA (nusinersen), and a pivotal proof of principle that therapeutic antisense oligonucleotide (ASO) treatment can effectively target the central nervous system (CNS) to treat neurological and neuromuscular disease. Nusinersen is a steric block ASO that binds the SMN2 messenger RNA and promotes exon 7 inclusion and thus increases full length SMN expression. Here, we consider the implications of this therapeutic landmark for SMA therapeutics and discuss how future developments will need to address the challenges of delivering ASO therapies to the CNS, with appropriate efficiency and activity, and how SMN-based therapy should be used in combination with complementary strategies to provide an integrated approach to treat CNS and peripheral pathologies in SMA.
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Affiliation(s)
- Matthew J A Wood
- Department of Physiology, Anatomy and Genetics, University of Oxford OX1 3QX, Oxford, UK
| | - Kevin Talbot
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, UK
| | - Melissa Bowerman
- Department of Physiology, Anatomy and Genetics, University of Oxford OX1 3QX, Oxford, UK
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23
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Wang Y, Wan GH, Wu YM, Wang HS, Wang HF, Zhang G, Lu LL, Li ZQ, Chan KY, Zhou Y, Cai SH, Qi YF, Du J. AP-1 confers resistance to anti-cancer therapy by activating XIAP. Oncotarget 2018; 9:14124-37. [PMID: 29581832 DOI: 10.18632/oncotarget.23897] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 10/30/2017] [Indexed: 02/06/2023] Open
Abstract
The underlying cause of treatment failure in many cancer patients is intrinsic and acquired resistance to chemotherapy. Recently, histone deacetylase (HDAC) inhibitors have developed into a promising cancer treatment. However, resistance mechanism induced by HDAC inhibitors remains largely unknown. Here we report that a HDAC inhibitor, JNJ-2648158 induced transcription of XIAP by activating AP-1 expression, which conferring resistance to chemotherapeutics. Our results showed that high expression of c-Fos caused by HDAC inhibitor promoted AP-1 formation during acquired resistance towards chemo-drugs, indicating an extremely poor clinical outcome in breast cancers and liver cancers. Our study reveals a novel regulatory mechanism towards chemo-drug resistance, and suggests that XIAP may serve as a potential therapeutic target in those chemo-resistant cancer cells.
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24
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Singh NN, Howell MD, Androphy EJ, Singh RN. How the discovery of ISS-N1 led to the first medical therapy for spinal muscular atrophy. Gene Ther 2017; 24:520-526. [PMID: 28485722 DOI: 10.1038/gt.2017.34] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Revised: 04/14/2017] [Accepted: 04/26/2017] [Indexed: 12/14/2022]
Abstract
Spinal muscular atrophy (SMA), a prominent genetic disease of infant mortality, is caused by low levels of survival motor neuron (SMN) protein owing to deletions or mutations of the SMN1 gene. SMN2, a nearly identical copy of SMN1 present in humans, cannot compensate for the loss of SMN1 because of predominant skipping of exon 7 during pre-mRNA splicing. With the recent US Food and Drug Administration approval of nusinersen (Spinraza), the potential for correction of SMN2 exon 7 splicing as an SMA therapy has been affirmed. Nusinersen is an antisense oligonucleotide that targets intronic splicing silencer N1 (ISS-N1) discovered in 2004 at the University of Massachusetts Medical School. ISS-N1 has emerged as the model target for testing the therapeutic efficacy of antisense oligonucleotides using different chemistries as well as different mouse models of SMA. Here, we provide a historical account of events that led to the discovery of ISS-N1 and describe the impact of independent validations that raised the profile of ISS-N1 as one of the most potent antisense targets for the treatment of a genetic disease. Recent approval of nusinersen provides a much-needed boost for antisense technology that is just beginning to realize its potential. Beyond treating SMA, the ISS-N1 target offers myriad potentials for perfecting various aspects of the nucleic-acid-based technology for the amelioration of the countless number of pathological conditions.
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Affiliation(s)
- N N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA, USA
| | - M D Howell
- Department of Biomedical Sciences, Iowa State University, Ames, IA, USA
| | - E J Androphy
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - R N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA, USA
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25
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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: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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26
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Robin V, Griffith G, Carter JPL, Leumann CJ, Garcia L, Goyenvalle A. Efficient SMN Rescue following Subcutaneous Tricyclo-DNA Antisense Oligonucleotide Treatment. Mol Ther Nucleic Acids 2017. [PMID: 28624227 PMCID: PMC5415958 DOI: 10.1016/j.omtn.2017.02.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Spinal muscular atrophy (SMA) is a recessive disease caused by mutations in the SMN1 gene, which encodes the protein survival motor neuron (SMN), whose absence dramatically affects the survival of motor neurons. In humans, the severity of the disease is lessened by the presence of a gene copy, SMN2. SMN2 differs from SMN1 by a C-to-T transition in exon 7, which modifies pre-mRNA splicing and prevents successful SMN synthesis. Splice-switching approaches using antisense oligonucleotides (AONs) have already been shown to correct this SMN2 gene transition, providing a therapeutic avenue for SMA. However, AON administration to the CNS presents additional hurdles. In this study, we show that systemic delivery of tricyclo-DNA (tcDNA) AONs in a type III SMA mouse augments retention of exon 7 in SMN2 mRNA both in peripheral organs and the CNS. Mild type III SMA mice were selected as opposed to the severe type I model in order to test tcDNA efficacy and their ability to enter the CNS after maturation of the blood brain barrier (BBB). Furthermore, subcutaneous treatment significantly improved the necrosis phenotype and respiratory function. In summary, our data support that tcDNA oligomers effectively cross the blood-brain barrier and offer a promising systemic alternative for treating SMA.
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Affiliation(s)
- Valérie Robin
- Université Versailles Saint Quentin, INSERM U1179, 78180 Montigny-le-Bretonneux, France.
| | - Graziella Griffith
- Université Versailles Saint Quentin, INSERM U1179, 78180 Montigny-le-Bretonneux, France
| | - John-Paul L Carter
- Université Versailles Saint Quentin, INSERM U1179, 78180 Montigny-le-Bretonneux, France
| | - Christian J Leumann
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
| | - Luis Garcia
- Université Versailles Saint Quentin, INSERM U1179, 78180 Montigny-le-Bretonneux, France
| | - Aurélie Goyenvalle
- Université Versailles Saint Quentin, INSERM U1179, 78180 Montigny-le-Bretonneux, France.
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27
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Singh RN, Howell MD, Ottesen EW, Singh NN. Diverse role of survival motor neuron protein. Biochim Biophys Acta Gene Regul Mech 2017; 1860:299-315. [PMID: 28095296 PMCID: PMC5325804 DOI: 10.1016/j.bbagrm.2016.12.008] [Citation(s) in RCA: 178] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 12/23/2016] [Accepted: 12/30/2016] [Indexed: 02/07/2023]
Abstract
The multifunctional Survival Motor Neuron (SMN) protein is required for the survival of all organisms of the animal kingdom. SMN impacts various aspects of RNA metabolism through the formation and/or interaction with ribonucleoprotein (RNP) complexes. SMN regulates biogenesis of small nuclear RNPs, small nucleolar RNPs, small Cajal body-associated RNPs, signal recognition particles and telomerase. SMN also plays an important role in DNA repair, transcription, pre-mRNA splicing, histone mRNA processing, translation, selenoprotein synthesis, macromolecular trafficking, stress granule formation, cell signaling and cytoskeleton maintenance. The tissue-specific requirement of SMN is dictated by the variety and the abundance of its interacting partners. Reduced expression of SMN causes spinal muscular atrophy (SMA), a leading genetic cause of infant mortality. SMA displays a broad spectrum ranging from embryonic lethality to an adult onset. Aberrant expression and/or localization of SMN has also been associated with male infertility, inclusion body myositis, amyotrophic lateral sclerosis and osteoarthritis. This review provides a summary of various SMN functions with implications to a better understanding of SMA and other pathological conditions.
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Affiliation(s)
- Ravindra N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States.
| | - Matthew D Howell
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States
| | - Eric W Ottesen
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States
| | - Natalia N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States
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28
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Thomson AK, Somers E, Powis RA, Shorrock HK, Murphy K, Swoboda KJ, Gillingwater TH, Parson SH. Survival of motor neurone protein is required for normal postnatal development of the spleen. J Anat 2016; 230:337-346. [PMID: 27726134 DOI: 10.1111/joa.12546] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/16/2016] [Indexed: 01/09/2023] Open
Abstract
Spinal muscular atrophy (SMA), traditionally described as a predominantly childhood form of motor neurone disease, is the leading genetic cause of infant mortality. Although motor neurones are undoubtedly the primary affected cell type, the severe infantile form of SMA (Type I SMA) is now widely recognised to represent a multisystem disorder where a variety of organs and systems in the body are also affected. Here, we report that the spleen is disproportionately small in the 'Taiwanese' murine model of severe SMA (Smn-/- ;SMN2tg/0 ), correlated to low levels of cell proliferation and increased cell death. Spleen lacks its distinctive red appearance and presents with a degenerated capsule and a disorganised fibrotic architecture. Histologically distinct white pulp failed to form and this was reflected in an almost complete absence of B lymphocytes necessary for normal immune function. In addition, megakaryoctyes persisted in the red pulp. However, the vascular density remained unchanged in SMA spleen. Assessment of the spleen in SMA patients with the infantile form of the disease indicated a range of pathologies. We conclude that development of the spleen fails to occur normally in SMA mouse models and human patients. Thus, further analysis of immune function is likely to be required to fully understand the full extent of systemic disease pathology in SMA.
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Affiliation(s)
- Alison K Thomson
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland.,Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh, Scotland
| | - Eilidh Somers
- Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh, Scotland.,Centre for Integrative Physiology, University of Edinburgh, Edinburgh, Scotland
| | - Rachael A Powis
- Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh, Scotland.,Centre for Integrative Physiology, University of Edinburgh, Edinburgh, Scotland
| | - Hannah K Shorrock
- Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh, Scotland.,Centre for Integrative Physiology, University of Edinburgh, Edinburgh, Scotland
| | - Kelley Murphy
- Department of Biology, Morgan State University, Baltimore, MD, USA
| | - Kathryn J Swoboda
- Department of Neurology, Center for Human Genetics Research, Massachusetts General Hospital, Boston, MA, USA
| | - Thomas H Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh, Scotland.,Centre for Integrative Physiology, University of Edinburgh, Edinburgh, Scotland
| | - Simon H Parson
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland.,Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh, Scotland
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29
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Szunyogova E, Zhou H, Maxwell GK, Powis RA, Francesco M, Gillingwater TH, Parson SH. Survival Motor Neuron (SMN) protein is required for normal mouse liver development. Sci Rep 2016; 6:34635. [PMID: 27698380 PMCID: PMC5048144 DOI: 10.1038/srep34635] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 09/12/2016] [Indexed: 01/15/2023] Open
Abstract
Spinal Muscular Atrophy (SMA) is caused by mutation or deletion of the survival motor neuron 1 (SMN1) gene. Decreased levels of, cell-ubiquitous, SMN protein is associated with a range of systemic pathologies reported in severe patients. Despite high levels of SMN protein in normal liver, there is no comprehensive study of liver pathology in SMA. We describe failed liver development in response to reduced SMN levels, in a mouse model of severe SMA. The SMA liver is dark red, small and has: iron deposition; immature sinusoids congested with blood; persistent erythropoietic elements and increased immature red blood cells; increased and persistent megakaryocytes which release high levels of platelets found as clot-like accumulations in the heart. Myelopoiesis in contrast, was unaffected. Further analysis revealed significant molecular changes in SMA liver, consistent with the morphological findings. Antisense treatment from birth with PMO25, increased lifespan and ameliorated all morphological defects in liver by postnatal day 21. Defects in the liver are evident at birth, prior to motor system pathology, and impair essential liver function in SMA. Liver is a key recipient of SMA therapies, and systemically delivered antisense treatment, completely rescued liver pathology. Liver therefore, represents an important therapeutic target in SMA.
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Affiliation(s)
- Eva Szunyogova
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
- Euan MacDonald Center for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Haiyan Zhou
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, London, United Kingdom
| | - Gillian K. Maxwell
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Rachael A. Powis
- Euan MacDonald Center for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Center for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Muntoni Francesco
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, London, United Kingdom
| | - Thomas H. Gillingwater
- Euan MacDonald Center for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Center for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Simon H. Parson
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
- Euan MacDonald Center for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
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30
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Dimitriadi M, Derdowski A, Kalloo G, Maginnis MS, O'Hern P, Bliska B, Sorkaç A, Nguyen KCQ, Cook SJ, Poulogiannis G, Atwood WJ, Hall DH, Hart AC. Decreased function of survival motor neuron protein impairs endocytic pathways. Proc Natl Acad Sci U S A 2016; 113:E4377-86. [PMID: 27402754 PMCID: PMC4968725 DOI: 10.1073/pnas.1600015113] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Spinal muscular atrophy (SMA) is caused by depletion of the ubiquitously expressed survival motor neuron (SMN) protein, with 1 in 40 Caucasians being heterozygous for a disease allele. SMN is critical for the assembly of numerous ribonucleoprotein complexes, yet it is still unclear how reduced SMN levels affect motor neuron function. Here, we examined the impact of SMN depletion in Caenorhabditis elegans and found that decreased function of the SMN ortholog SMN-1 perturbed endocytic pathways at motor neuron synapses and in other tissues. Diminished SMN-1 levels caused defects in C. elegans neuromuscular function, and smn-1 genetic interactions were consistent with an endocytic defect. Changes were observed in synaptic endocytic proteins when SMN-1 levels decreased. At the ultrastructural level, defects were observed in endosomal compartments, including significantly fewer docked synaptic vesicles. Finally, endocytosis-dependent infection by JC polyomavirus (JCPyV) was reduced in human cells with decreased SMN levels. Collectively, these results demonstrate for the first time, to our knowledge, that SMN depletion causes defects in endosomal trafficking that impair synaptic function, even in the absence of motor neuron cell death.
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Affiliation(s)
- Maria Dimitriadi
- Department of Neuroscience, Brown University, Providence, RI 02912; Department of Biological and Environmental Sciences, University of Hertfordshire, Hatfield AL10 9AB, United Kingdom
| | - Aaron Derdowski
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912
| | - Geetika Kalloo
- Department of Neuroscience, Brown University, Providence, RI 02912
| | - Melissa S Maginnis
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912; Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME 04469
| | - Patrick O'Hern
- Department of Neuroscience, Brown University, Providence, RI 02912
| | - Bryn Bliska
- Department of Neuroscience, Brown University, Providence, RI 02912
| | - Altar Sorkaç
- Department of Neuroscience, Brown University, Providence, RI 02912
| | - Ken C Q Nguyen
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Steven J Cook
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461
| | - George Poulogiannis
- Chester Beatty Labs, The Institute of Cancer Research, London SW3 6JB, United Kingdom
| | - Walter J Atwood
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912
| | - David H Hall
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Anne C Hart
- Department of Neuroscience, Brown University, Providence, RI 02912;
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31
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Hunter G, Powis RA, Jones RA, Groen EJN, Shorrock HK, Lane FM, Zheng Y, Sherman DL, Brophy PJ, Gillingwater TH. Restoration of SMN in Schwann cells reverses myelination defects and improves neuromuscular function in spinal muscular atrophy. Hum Mol Genet 2016; 25:2853-2861. [PMID: 27170316 PMCID: PMC5181642 DOI: 10.1093/hmg/ddw141] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 04/27/2016] [Accepted: 04/29/2016] [Indexed: 12/19/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disease caused by low levels of SMN protein, primarily affecting lower motor neurons. Recent evidence from SMA and related conditions suggests that glial cells can influence disease severity. Here, we investigated the role of glial cells in the peripheral nervous system by creating SMA mice selectively overexpressing SMN in myelinating Schwann cells (Smn−/−;SMN2tg/0;SMN1SC). Restoration of SMN protein levels restricted solely to Schwann cells reversed myelination defects, significantly improved neuromuscular function and ameliorated neuromuscular junction pathology in SMA mice. However, restoration of SMN in Schwann cells had no impact on motor neuron soma loss from the spinal cord or ongoing systemic and peripheral pathology. This study provides evidence for a defined, intrinsic contribution of glial cells to SMA disease pathogenesis and suggests that therapies designed to include Schwann cells in their target tissues are likely to be required in order to rescue myelination defects and associated disease symptoms.
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Affiliation(s)
- Gillian Hunter
- Department of Life Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK,
- 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 and
| | - Rachael A Powis
- 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 and
| | - Ross A Jones
- 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 and
| | - Ewout J N Groen
- 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 and
| | - Hannah K Shorrock
- 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 and
| | - Fiona M Lane
- 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 and
| | - Yinan Zheng
- 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 and
| | - Diane L Sherman
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Peter J Brophy
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh, EH16 4SB, 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 and
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32
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Sintusek P, Catapano F, Angkathunkayul N, Marrosu E, Parson SH, Morgan JE, Muntoni F, Zhou H. Histopathological Defects in Intestine in Severe Spinal Muscular Atrophy Mice Are Improved by Systemic Antisense Oligonucleotide Treatment. PLoS One 2016; 11:e0155032. [PMID: 27163330 PMCID: PMC4862622 DOI: 10.1371/journal.pone.0155032] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 04/22/2016] [Indexed: 12/28/2022] Open
Abstract
Gastrointestinal (GI) defects, including gastroesophageal reflux, constipation and delayed gastric emptying, are common in patients with spinal muscular atrophy (SMA). Similar GI dysmotility has been identified in mouse models with survival of motor neuron (SMN) protein deficiency. We previously described vascular defects in skeletal muscle and spinal cord of SMA mice and we hypothesized that similar defects could be involved in the GI pathology observed in these mice. We therefore investigated the gross anatomical structure, enteric vasculature and neurons in the small intestine in a severe mouse model of SMA. We also assessed the therapeutic response of GI histopathology to systemic administration of morpholino antisense oligonucleotide (AON) designed to increase SMN protein expression. Significant anatomical and histopathological abnormalities, with striking reduction of vascular density, overabundance of enteric neurons and increased macrophage infiltration, were detected in the small intestine in SMA mice. After systemic AON treatment in neonatal mice, all the abnormalities observed were significantly restored to near-normal levels. We conclude that the observed GI histopathological phenotypes and functional defects observed in these SMA mice are strongly linked to SMN deficiency which can be rescued by systemic administration of AON. This study on the histopathological changes in the gastrointestinal system in severe SMA mice provides further indication of the complex role that SMN plays in multiple tissues and suggests that at least in SMA mice restoration of SMN production in peripheral tissues is essential for optimal outcome.
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MESH Headings
- Animals
- Animals, Newborn
- Disease Models, Animal
- Gene Expression
- Genetic Therapy/methods
- Heterozygote
- Homozygote
- Humans
- Injections, Subcutaneous
- Intestine, Small/blood supply
- Intestine, Small/drug effects
- Intestine, Small/innervation
- Intestine, Small/pathology
- Macrophages/drug effects
- Macrophages/metabolism
- Macrophages/pathology
- Mice
- Mice, Transgenic
- Morpholinos/administration & dosage
- Motor Neurons/drug effects
- Motor Neurons/metabolism
- Motor Neurons/pathology
- Muscular Atrophy, Spinal/genetics
- Muscular Atrophy, Spinal/metabolism
- Muscular Atrophy, Spinal/pathology
- Muscular Atrophy, Spinal/therapy
- Oligonucleotides, Antisense/administration & dosage
- Phenotype
- Spinal Cord/blood supply
- Spinal Cord/drug effects
- Spinal Cord/pathology
- Survival of Motor Neuron 1 Protein/agonists
- Survival of Motor Neuron 1 Protein/genetics
- Survival of Motor Neuron 1 Protein/metabolism
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Affiliation(s)
- Palittiya Sintusek
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, London, United Kingdom
- Division of Gastroenterology and Hepatology, Department of Pediatrics, Faculty of Medicine, King Chulalongkorn Memorial Hospital, Chulalongkorn University, Bangkok, Thailand
| | - Francesco Catapano
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, London, United Kingdom
| | - Napat Angkathunkayul
- Department of Pathology, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Elena Marrosu
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, London, United Kingdom
| | - Simon H. Parson
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
- Euan MacDonald Center for Motor Neuron Disease Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Jennifer E. Morgan
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, London, United Kingdom
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, London, United Kingdom
- * E-mail: (HZ); (FM)
| | - Haiyan Zhou
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, London, United Kingdom
- * E-mail: (HZ); (FM)
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33
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Lin TL, Chen TH, Hsu YY, Cheng YH, Juang BT, Jong YJ. Selective Neuromuscular Denervation in Taiwanese Severe SMA Mouse Can Be Reversed by Morpholino Antisense Oligonucleotides. PLoS One 2016; 11:e0154723. [PMID: 27124114 PMCID: PMC4849667 DOI: 10.1371/journal.pone.0154723] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 04/18/2016] [Indexed: 11/27/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive motor neuron disease caused by deficiency of the survival of motor neuron (SMN) protein, which leads to synaptic defects and spinal motor neuron death. Neuromuscular junction (NMJ) abnormalities have been found to be involved in SMA pathogenesis in the SMNΔ7 SMA mouse model. However, whether similar NMJ pathological findings present in another commonly used mouse model, the Taiwanese SMA mouse, has not been fully investigated. To examine the NMJs of the Taiwanese severe SMA mouse model (Smn-/-; SMN2tg/0), which is characterized by severe phenotype and death before postnatal day (P) 9, we investigated 25 axial and appendicular muscles from P1 to P9. We labelled the muscles with anti-neurofilament and anti-synaptophysin antibodies for nerve terminals and α-bungarotoxin for acetylcholine receptors (AChRs). We found that severe NMJ denervation (<50% fully innervated endplates) selectively occurred in the flexor digitorum brevis 2 and 3 (FDB-2/3) muscles from P5, and an increased percentage of fully denervated endplates correlated with SMA progression. Furthermore, synaptophysin signals were absent at the endplate compared to control littermate mice, suggesting that vesicle transport might only be affected at the end stage. Subsequently, we treated the Taiwanese severe SMA mice with morpholino (MO) antisense oligonucleotides (80 μg/g) via subcutaneous injection at P0. We found that MO significantly reversed the NMJ denervation in FDB-2/3 muscles and extended the survival of Taiwanese severe SMA mice. We conclude that early NMJ denervation in the FDB-2/3 muscles of Taiwanese severe SMA mice can be reversed by MO treatment. The FDB-2/3 muscles of Taiwanese severe SMA mice provide a very sensitive platform for assessing the effectiveness of drug treatments in SMA preclinical studies.
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Affiliation(s)
- Te-Lin Lin
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Tai-Heng Chen
- Division of Pediatric Emergency, Department of Emergency, Kaohsiung Medical University and Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Ya-Yun Hsu
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Yu-Hua Cheng
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Bi-Tzen Juang
- Department of Biological Science and Technology, College of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan
| | - Yuh-Jyh Jong
- Department of Biological Science and Technology, College of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan
- Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Institute of Molecular Medicine and Bioengineering, College of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan
- Departments of Pediatrics and Laboratory Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- * E-mail: ;
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34
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Ottesen EW, Howell MD, Singh NN, Seo J, Whitley EM, Singh RN. Severe impairment of male reproductive organ development in a low SMN expressing mouse model of spinal muscular atrophy. Sci Rep 2016; 6:20193. [PMID: 26830971 PMCID: PMC4735745 DOI: 10.1038/srep20193] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 12/23/2015] [Indexed: 12/21/2022] Open
Abstract
Spinal muscular atrophy (SMA) is caused by low levels of survival motor neuron (SMN), a multifunctional protein essential for higher eukaryotes. While SMN is one of the most scrutinized proteins associated with neurodegeneration, its gender-specific role in vertebrates remains unknown. We utilized a mild SMA model (C/C model) to examine the impact of low SMN on growth and development of mammalian sex organs. We show impaired testis development, degenerated seminiferous tubules, reduced sperm count and low fertility in C/C males, but no overt sex organ phenotype in C/C females. Underscoring an increased requirement for SMN expression, wild type testis showed extremely high levels of SMN protein compared to other tissues. Our results revealed severe perturbations in pathways critical to C/C male reproductive organ development and function, including steroid biosynthesis, apoptosis, and spermatogenesis. Consistent with enhanced apoptosis in seminiferous tubules of C/C testes, we recorded a drastic increase in cells with DNA fragmentation. SMN was expressed at high levels in adult C/C testis due to an adult-specific splicing switch, but could not compensate for low levels during early testicular development. Our findings uncover novel hallmarks of SMA disease progression and link SMN to general male infertility.
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Affiliation(s)
- Eric W Ottesen
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa 50011, USA
| | - Matthew D Howell
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa 50011, USA
| | - Natalia N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa 50011, USA
| | - Joonbae Seo
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa 50011, USA
| | - Elizabeth M Whitley
- Department of Veterinary Pathology, Iowa State University, Ames, Iowa 50011, USA
| | - Ravindra N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa 50011, USA
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35
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Cerveró C, Montull N, Tarabal O, Piedrafita L, Esquerda JE, Calderó J. Chronic Treatment with the AMPK Agonist AICAR Prevents Skeletal Muscle Pathology but Fails to Improve Clinical Outcome in a Mouse Model of Severe Spinal Muscular Atrophy. Neurotherapeutics 2016; 13:198-216. [PMID: 26582176 PMCID: PMC4720671 DOI: 10.1007/s13311-015-0399-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a genetic neuromuscular disorder characterized by spinal and brainstem motor neuron (MN) loss and skeletal muscle paralysis. Currently, there is no effective treatment other than supportive care to ameliorate the quality of life of patients with SMA. Some studies have reported that physical exercise, by improving muscle strength and motor function, is potentially beneficial in SMA. The adenosine monophosphate-activated protein kinase agonist 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) has been reported to be an exercise mimetic agent that is able to regulate muscle metabolism and increase endurance both at rest and during exercise. Chronic AICAR administration has been shown to ameliorate the dystrophic muscle phenotype and motor behavior in the mdx mouse, a model of Duchenne muscular dystrophy. Here, we investigated whether chronic AICAR treatment was able to elicit beneficial effects on motor abilities and neuromuscular histopathology in a mouse model of severe SMA (the SMNΔ7 mouse). We report that AICAR improved skeletal muscle atrophy and structural changes found in neuromuscular junctions of SMNΔ7 animals. However, although AICAR prevented the loss of glutamatergic excitatory synapses on MNs, this compound was not able to mitigate MN loss or the microglial and astroglial reaction occurring in the spinal cord of diseased mice. Moreover, no improvement in survival or motor performance was seen in SMNΔ7 animals treated with AICAR. The beneficial effects of AICAR in SMA found in our study are SMN-independent, as no changes in the expression of this protein were seen in the spinal cord and skeletal muscle of diseased animals treated with this compound.
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Affiliation(s)
- Clàudia Cerveró
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Av. Rovira Roure 80, 25198, Lleida, Catalonia, Spain
| | - Neus Montull
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Av. Rovira Roure 80, 25198, Lleida, Catalonia, Spain
| | - Olga Tarabal
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Av. Rovira Roure 80, 25198, Lleida, Catalonia, Spain
| | - Lídia Piedrafita
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Av. Rovira Roure 80, 25198, Lleida, Catalonia, Spain
| | - Josep E Esquerda
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Av. Rovira Roure 80, 25198, Lleida, Catalonia, Spain
| | - Jordi Calderó
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Av. Rovira Roure 80, 25198, Lleida, Catalonia, Spain.
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36
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Van Gronigen Caesar G, Dale JM, Osman EY, Garcia ML, Lorson CL, Schulz LC. Placental development in a mouse model of spinal muscular atrophy. Biochem Biophys Res Commun 2015; 470:82-87. [PMID: 26748185 DOI: 10.1016/j.bbrc.2015.12.120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 12/22/2015] [Indexed: 01/30/2023]
Abstract
Spinal Muscular Atrophy (SMA) is an autosomal recessive disorder, leading to fatal loss of motor neurons. It is caused by loss of function of the SMN gene, which is expressed throughout the body, and there is increasing evidence of dysfunction in non-neuronal tissues. Birthweight is one of most powerful prognostic factors for infants born with SMA, and intrauterine growth restriction is common. In the SMNΔ7 mouse model of SMA, pups with the disease lived 25% longer when their mothers were fed a higher fat, "breeder" diet. The placenta is responsible for transport of nutrients from mother to fetus, and is a major determinant of fetal growth. Thus, the present study tested the hypothesis that placental development is impaired in SMNΔ7 conceptuses. Detailed morphological characterization revealed no defects in SMNΔ7 placental development, and expression of key transcription factors regulating mouse placental development was unaffected. The intrauterine growth restriction observed in SMA infants likely does not result from impaired placental development.
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Affiliation(s)
- Gerialisa Van Gronigen Caesar
- Division of Biological Sciences, University of Missouri, Columbia, MO, USA; Department of Obstetrics, Gynecology and Women's Health, University of Missouri, Columbia, MO, USA
| | - Jeffrey M Dale
- Division of Biological Sciences, University of Missouri, Columbia, MO, USA; Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | - Erkan Y Osman
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, USA; Department of Veterinary Pathobiology, University of Missouri, Columbia, MO, USA
| | - Michael L Garcia
- Division of Biological Sciences, University of Missouri, Columbia, MO, USA; Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | - Christian L Lorson
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, USA; Department of Veterinary Pathobiology, University of Missouri, Columbia, MO, USA; Department of Molecular Microbiology and Immunology, University of Missouri, Columbia, MO, USA
| | - Laura C Schulz
- Division of Biological Sciences, University of Missouri, Columbia, MO, USA; Department of Obstetrics, Gynecology and Women's Health, University of Missouri, Columbia, MO, USA.
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37
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McGovern VL, Iyer CC, Arnold WD, Gombash SE, Zaworski PG, Blatnik AJ, Foust KD, Burghes AHM. SMN expression is required in motor neurons to rescue electrophysiological deficits in the SMNΔ7 mouse model of SMA. Hum Mol Genet 2015; 24:5524-41. [PMID: 26206889 PMCID: PMC4572068 DOI: 10.1093/hmg/ddv283] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 06/10/2015] [Accepted: 07/13/2015] [Indexed: 12/23/2022] Open
Abstract
Proximal spinal muscular atrophy (SMA) is the most frequent cause of hereditary infant mortality. SMA is an autosomal recessive neuromuscular disorder that results from the loss of the Survival Motor Neuron 1 (SMN1) gene and retention of the SMN2 gene. The SMN2 gene produces an insufficient amount of full-length SMN protein that results in loss of motor neurons in the spinal cord and subsequent muscle paralysis. Previously we have shown that overexpression of human SMN in neurons in the SMA mouse ameliorates the SMA phenotype while overexpression of human SMN in skeletal muscle had no effect. Using Cre recombinase, here we show that either deletion or replacement of Smn in motor neurons (ChAT-Cre) significantly alters the functional output of the motor unit as measured with compound muscle action potential and motor unit number estimation. However ChAT-Cre alone did not alter the survival of SMA mice by replacement and did not appreciably affect survival when used to deplete SMN. However replacement of Smn in both neurons and glia in addition to the motor neuron (Nestin-Cre and ChAT-Cre) resulted in the greatest improvement in survival of the mouse and in some instances complete rescue was achieved. These findings demonstrate that high expression of SMN in the motor neuron is both necessary and sufficient for proper function of the motor unit. Furthermore, in the mouse high expression of SMN in neurons and glia, in addition to motor neurons, has a major impact on survival.
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Affiliation(s)
- Vicki L McGovern
- Department of Molecular and Cellular Biochemistry, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Chitra C Iyer
- Department of Molecular and Cellular Biochemistry, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - W David Arnold
- Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA Department of Physical Medicine and Rehabilitation, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA and
| | - Sara E Gombash
- Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA and
| | | | - Anton J Blatnik
- Department of Molecular and Cellular Biochemistry, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Kevin D Foust
- Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA and
| | - Arthur H M Burghes
- Department of Molecular and Cellular Biochemistry, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
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38
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Genabai NK, Ahmad S, Zhang Z, Jiang X, Gabaldon CA, Gangwani L. Genetic inhibition of JNK3 ameliorates spinal muscular atrophy. Hum Mol Genet 2015; 24:6986-7004. [PMID: 26423457 DOI: 10.1093/hmg/ddv401] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 09/21/2015] [Indexed: 01/04/2023] Open
Abstract
Mutation of the Survival Motor Neuron 1 (SMN1) gene causes spinal muscular atrophy (SMA), an autosomal recessive neurodegenerative disorder that occurs in early childhood. Degeneration of spinal motor neurons caused by SMN deficiency results in progressive muscle atrophy and death in SMA. The molecular mechanism underlying neurodegeneration in SMA is unknown. No treatment is available to prevent neurodegeneration and reduce the burden of illness in SMA. We report that the c-Jun NH2-terminal kinase (JNK) signaling pathway mediates neurodegeneration in SMA. The neuron-specific isoform JNK3 is required for neuron degeneration caused by SMN deficiency. JNK3 deficiency reduces degeneration of cultured neurons caused by low levels of SMN. Genetic inhibition of JNK pathway in vivo by Jnk3 knockout results in amelioration of SMA phenotype. JNK3 deficiency prevents the loss of spinal cord motor neurons, reduces muscle degeneration, improves muscle fiber thickness and muscle growth, improves motor function and overall growth and increases lifespan of mice with SMA that shows a systemic rescue of phenotype by a SMN-independent mechanism. JNK3 represents a potential (non-SMN) therapeutic target for the treatment of SMA.
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Affiliation(s)
- Naresh K Genabai
- Center of Emphasis in Neurosciences and Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, TX 79905, USA
| | - Saif Ahmad
- Center of Emphasis in Neurosciences and Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, TX 79905, USA
| | - Zhanying Zhang
- Center of Emphasis in Neurosciences and Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, TX 79905, USA
| | - Xiaoting Jiang
- Center of Emphasis in Neurosciences and Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, TX 79905, USA
| | - Cynthia A Gabaldon
- Center of Emphasis in Neurosciences and Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, TX 79905, USA
| | - Laxman Gangwani
- Center of Emphasis in Neurosciences and Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, TX 79905, USA
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39
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Singh NN, Lee BM, DiDonato CJ, Singh RN. Mechanistic principles of antisense targets for the treatment of spinal muscular atrophy. Future Med Chem 2015; 7:1793-808. [PMID: 26381381 DOI: 10.4155/fmc.15.101] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a major neurodegenerative disorder of children and infants. SMA is primarily caused by low levels of SMN protein owing to deletions or mutations of the SMN1 gene. SMN2, a nearly identical copy of SMN1, fails to compensate for the loss of the production of the functional SMN protein due to predominant skipping of exon 7. Several compounds, including antisense oligonucleotides (ASOs) that elevate SMN protein from SMN2 hold the promise for treatment. An ASO-based drug currently under Phase III clinical trial employs intronic splicing silencer N1 (ISS-N1) as its target. Cumulative studies on ISS-N1 reveal a wealth of information with significance to the overall therapeutic development for SMA. Here, the authors summarize the mechanistic principles behind various antisense targets currently available for SMA therapy.
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40
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Rigo F, Seth PP, Bennett CF. Antisense oligonucleotide-based therapies for diseases caused by pre-mRNA processing defects. Adv Exp Med Biol 2014; 825:303-52. [PMID: 25201110 DOI: 10.1007/978-1-4939-1221-6_9] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Before a messenger RNA (mRNA) is translated into a protein in the cytoplasm, its pre-mRNA precursor is extensively processed through capping, splicing and polyadenylation in the nucleus. Defects in the processing of pre-mRNAs due to mutations in RNA sequences often cause disease. Traditional small molecules or protein-based therapeutics are not well suited for correcting processing defects by targeting RNA. However, antisense oligonucleotides (ASOs) designed to bind RNA by Watson-Crick base pairing can target most RNA transcripts and have emerged as the ideal therapeutic agents for diseases that are caused by pre-mRNA processing defects. Here we review the diverse ASO-based mechanisms that can be exploited to modulate the expression of RNA. We also discuss how advancements in medicinal chemistry and a deeper understanding of the pharmacokinetic and toxicological properties of ASOs have enabled their use as therapeutic agents. We end by describing how ASOs have been used successfully to treat various pre-mRNA processing diseases in animal models.
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Affiliation(s)
- Frank Rigo
- Isis Pharmaceuticals, 2855 Gazelle Court, Carlsbad, CA, USA,
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41
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Abstract
Rare neuromuscular diseases encompass many diverse and debilitating musculoskeletal disorders, ranging from ultra-orphan conditions that affect only a few families, to the so-called ‘common’ orphan diseases like Duchenne muscular dystrophy (DMD) and spinal muscular atrophy (SMA), which affect several thousand individuals worldwide. Increasingly, pharmaceutical and biotechnology companies, in an effort to improve productivity and rebuild dwindling pipelines, are shifting their business models away from the formerly popular ‘blockbuster’ strategy, with rare diseases being an area of increased focus in recent years. As a consequence of this paradigm shift, coupled with high-profile campaigns by not-for-profit organisations and patient advocacy groups, rare neuromuscular diseases are attracting considerable attention as new therapeutic areas for improved drug therapy. Much pioneering work has taken place to elucidate the underlying pathological mechanisms of many rare neuromuscular diseases. This, in conjunction with the availability of new screening technologies, has inspired the development of several truly innovative therapeutic strategies aimed at correcting the underlying pathology. A survey of medicinal chemistry approaches and the resulting clinical progress for new therapeutic agents targeting this devastating class of degenerative diseases is presented, using DMD and SMA as examples. Complementary strategies using small-molecule drugs and biological agents are included.
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Affiliation(s)
- Graham M. Wynne
- Chemistry Research Laboratory, University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
| | - Angela J. Russell
- Chemistry Research Laboratory, University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
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42
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Wishart TM, Mutsaers CA, Riessland M, Reimer MM, Hunter G, Hannam ML, Eaton SL, Fuller HR, Roche SL, Somers E, Morse R, Young PJ, Lamont DJ, Hammerschmidt M, Joshi A, Hohenstein P, Morris GE, Parson SH, Skehel PA, Becker T, Robinson IM, Becker CG, Wirth B, Gillingwater TH. Dysregulation of ubiquitin homeostasis and β-catenin signaling promote spinal muscular atrophy. J Clin Invest 2014; 124:1821-34. [PMID: 24590288 PMCID: PMC3973095 DOI: 10.1172/jci71318] [Citation(s) in RCA: 141] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 12/20/2013] [Indexed: 01/09/2023] Open
Abstract
The autosomal recessive neurodegenerative disease spinal muscular atrophy (SMA) results from low levels of survival motor neuron (SMN) protein; however, it is unclear how reduced SMN promotes SMA development. Here, we determined that ubiquitin-dependent pathways regulate neuromuscular pathology in SMA. Using mouse models of SMA, we observed widespread perturbations in ubiquitin homeostasis, including reduced levels of ubiquitin-like modifier activating enzyme 1 (UBA1). SMN physically interacted with UBA1 in neurons, and disruption of Uba1 mRNA splicing was observed in the spinal cords of SMA mice exhibiting disease symptoms. Pharmacological or genetic suppression of UBA1 was sufficient to recapitulate an SMA-like neuromuscular pathology in zebrafish, suggesting that UBA1 directly contributes to disease pathogenesis. Dysregulation of UBA1 and subsequent ubiquitination pathways led to β-catenin accumulation, and pharmacological inhibition of β-catenin robustly ameliorated neuromuscular pathology in zebrafish, Drosophila, and mouse models of SMA. UBA1-associated disruption of β-catenin was restricted to the neuromuscular system in SMA mice; therefore, pharmacological inhibition of β-catenin in these animals failed to prevent systemic pathology in peripheral tissues and organs, indicating fundamental molecular differences between neuromuscular and systemic SMA pathology. Our data indicate that SMA-associated reduction of UBA1 contributes to neuromuscular pathogenesis through disruption of ubiquitin homeostasis and subsequent β-catenin signaling, highlighting ubiquitin homeostasis and β-catenin as potential therapeutic targets for SMA.
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Affiliation(s)
- Thomas M. Wishart
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom.
Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom.
Peninsula College of Medicine and Dentistry (Universities of Exeter and Plymouth), John Bull Building, Research Way, Tamar Science Park, Plymouth, United Kingdom.
Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom, and Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom.
Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, United Kingdom.
Fingerprints Proteomics Facility, Dundee University, Dundee, United Kingdom.
Institute of Developmental Biology, University of Cologne, Cologne, Germany.
Division of Developmental Biology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Medical Sciences, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Chantal A. Mutsaers
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom.
Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom.
Peninsula College of Medicine and Dentistry (Universities of Exeter and Plymouth), John Bull Building, Research Way, Tamar Science Park, Plymouth, United Kingdom.
Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom, and Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom.
Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, United Kingdom.
Fingerprints Proteomics Facility, Dundee University, Dundee, United Kingdom.
Institute of Developmental Biology, University of Cologne, Cologne, Germany.
Division of Developmental Biology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Medical Sciences, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Markus Riessland
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom.
Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom.
Peninsula College of Medicine and Dentistry (Universities of Exeter and Plymouth), John Bull Building, Research Way, Tamar Science Park, Plymouth, United Kingdom.
Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom, and Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom.
Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, United Kingdom.
Fingerprints Proteomics Facility, Dundee University, Dundee, United Kingdom.
Institute of Developmental Biology, University of Cologne, Cologne, Germany.
Division of Developmental Biology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Medical Sciences, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Michell M. Reimer
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom.
Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom.
Peninsula College of Medicine and Dentistry (Universities of Exeter and Plymouth), John Bull Building, Research Way, Tamar Science Park, Plymouth, United Kingdom.
Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom, and Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom.
Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, United Kingdom.
Fingerprints Proteomics Facility, Dundee University, Dundee, United Kingdom.
Institute of Developmental Biology, University of Cologne, Cologne, Germany.
Division of Developmental Biology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Medical Sciences, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Gillian Hunter
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom.
Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom.
Peninsula College of Medicine and Dentistry (Universities of Exeter and Plymouth), John Bull Building, Research Way, Tamar Science Park, Plymouth, United Kingdom.
Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom, and Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom.
Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, United Kingdom.
Fingerprints Proteomics Facility, Dundee University, Dundee, United Kingdom.
Institute of Developmental Biology, University of Cologne, Cologne, Germany.
Division of Developmental Biology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Medical Sciences, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Marie L. Hannam
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom.
Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom.
Peninsula College of Medicine and Dentistry (Universities of Exeter and Plymouth), John Bull Building, Research Way, Tamar Science Park, Plymouth, United Kingdom.
Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom, and Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom.
Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, United Kingdom.
Fingerprints Proteomics Facility, Dundee University, Dundee, United Kingdom.
Institute of Developmental Biology, University of Cologne, Cologne, Germany.
Division of Developmental Biology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Medical Sciences, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Samantha L. Eaton
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom.
Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom.
Peninsula College of Medicine and Dentistry (Universities of Exeter and Plymouth), John Bull Building, Research Way, Tamar Science Park, Plymouth, United Kingdom.
Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom, and Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom.
Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, United Kingdom.
Fingerprints Proteomics Facility, Dundee University, Dundee, United Kingdom.
Institute of Developmental Biology, University of Cologne, Cologne, Germany.
Division of Developmental Biology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Medical Sciences, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Heidi R. Fuller
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom.
Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom.
Peninsula College of Medicine and Dentistry (Universities of Exeter and Plymouth), John Bull Building, Research Way, Tamar Science Park, Plymouth, United Kingdom.
Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom, and Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom.
Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, United Kingdom.
Fingerprints Proteomics Facility, Dundee University, Dundee, United Kingdom.
Institute of Developmental Biology, University of Cologne, Cologne, Germany.
Division of Developmental Biology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Medical Sciences, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Sarah L. Roche
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom.
Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom.
Peninsula College of Medicine and Dentistry (Universities of Exeter and Plymouth), John Bull Building, Research Way, Tamar Science Park, Plymouth, United Kingdom.
Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom, and Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom.
Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, United Kingdom.
Fingerprints Proteomics Facility, Dundee University, Dundee, United Kingdom.
Institute of Developmental Biology, University of Cologne, Cologne, Germany.
Division of Developmental Biology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Medical Sciences, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Eilidh Somers
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom.
Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom.
Peninsula College of Medicine and Dentistry (Universities of Exeter and Plymouth), John Bull Building, Research Way, Tamar Science Park, Plymouth, United Kingdom.
Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom, and Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom.
Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, United Kingdom.
Fingerprints Proteomics Facility, Dundee University, Dundee, United Kingdom.
Institute of Developmental Biology, University of Cologne, Cologne, Germany.
Division of Developmental Biology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Medical Sciences, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Robert Morse
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom.
Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom.
Peninsula College of Medicine and Dentistry (Universities of Exeter and Plymouth), John Bull Building, Research Way, Tamar Science Park, Plymouth, United Kingdom.
Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom, and Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom.
Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, United Kingdom.
Fingerprints Proteomics Facility, Dundee University, Dundee, United Kingdom.
Institute of Developmental Biology, University of Cologne, Cologne, Germany.
Division of Developmental Biology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Medical Sciences, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Philip J. Young
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom.
Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom.
Peninsula College of Medicine and Dentistry (Universities of Exeter and Plymouth), John Bull Building, Research Way, Tamar Science Park, Plymouth, United Kingdom.
Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom, and Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom.
Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, United Kingdom.
Fingerprints Proteomics Facility, Dundee University, Dundee, United Kingdom.
Institute of Developmental Biology, University of Cologne, Cologne, Germany.
Division of Developmental Biology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Medical Sciences, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Douglas J. Lamont
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom.
Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom.
Peninsula College of Medicine and Dentistry (Universities of Exeter and Plymouth), John Bull Building, Research Way, Tamar Science Park, Plymouth, United Kingdom.
Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom, and Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom.
Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, United Kingdom.
Fingerprints Proteomics Facility, Dundee University, Dundee, United Kingdom.
Institute of Developmental Biology, University of Cologne, Cologne, Germany.
Division of Developmental Biology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Medical Sciences, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Matthias Hammerschmidt
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom.
Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom.
Peninsula College of Medicine and Dentistry (Universities of Exeter and Plymouth), John Bull Building, Research Way, Tamar Science Park, Plymouth, United Kingdom.
Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom, and Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom.
Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, United Kingdom.
Fingerprints Proteomics Facility, Dundee University, Dundee, United Kingdom.
Institute of Developmental Biology, University of Cologne, Cologne, Germany.
Division of Developmental Biology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Medical Sciences, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Anagha Joshi
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom.
Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom.
Peninsula College of Medicine and Dentistry (Universities of Exeter and Plymouth), John Bull Building, Research Way, Tamar Science Park, Plymouth, United Kingdom.
Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom, and Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom.
Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, United Kingdom.
Fingerprints Proteomics Facility, Dundee University, Dundee, United Kingdom.
Institute of Developmental Biology, University of Cologne, Cologne, Germany.
Division of Developmental Biology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Medical Sciences, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Peter Hohenstein
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom.
Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom.
Peninsula College of Medicine and Dentistry (Universities of Exeter and Plymouth), John Bull Building, Research Way, Tamar Science Park, Plymouth, United Kingdom.
Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom, and Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom.
Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, United Kingdom.
Fingerprints Proteomics Facility, Dundee University, Dundee, United Kingdom.
Institute of Developmental Biology, University of Cologne, Cologne, Germany.
Division of Developmental Biology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Medical Sciences, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Glenn E. Morris
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom.
Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom.
Peninsula College of Medicine and Dentistry (Universities of Exeter and Plymouth), John Bull Building, Research Way, Tamar Science Park, Plymouth, United Kingdom.
Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom, and Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom.
Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, United Kingdom.
Fingerprints Proteomics Facility, Dundee University, Dundee, United Kingdom.
Institute of Developmental Biology, University of Cologne, Cologne, Germany.
Division of Developmental Biology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Medical Sciences, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Simon H. Parson
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom.
Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom.
Peninsula College of Medicine and Dentistry (Universities of Exeter and Plymouth), John Bull Building, Research Way, Tamar Science Park, Plymouth, United Kingdom.
Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom, and Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom.
Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, United Kingdom.
Fingerprints Proteomics Facility, Dundee University, Dundee, United Kingdom.
Institute of Developmental Biology, University of Cologne, Cologne, Germany.
Division of Developmental Biology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Medical Sciences, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Paul A. Skehel
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom.
Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom.
Peninsula College of Medicine and Dentistry (Universities of Exeter and Plymouth), John Bull Building, Research Way, Tamar Science Park, Plymouth, United Kingdom.
Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom, and Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom.
Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, United Kingdom.
Fingerprints Proteomics Facility, Dundee University, Dundee, United Kingdom.
Institute of Developmental Biology, University of Cologne, Cologne, Germany.
Division of Developmental Biology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Medical Sciences, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Thomas Becker
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom.
Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom.
Peninsula College of Medicine and Dentistry (Universities of Exeter and Plymouth), John Bull Building, Research Way, Tamar Science Park, Plymouth, United Kingdom.
Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom, and Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom.
Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, United Kingdom.
Fingerprints Proteomics Facility, Dundee University, Dundee, United Kingdom.
Institute of Developmental Biology, University of Cologne, Cologne, Germany.
Division of Developmental Biology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Medical Sciences, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Iain M. Robinson
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom.
Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom.
Peninsula College of Medicine and Dentistry (Universities of Exeter and Plymouth), John Bull Building, Research Way, Tamar Science Park, Plymouth, United Kingdom.
Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom, and Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom.
Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, United Kingdom.
Fingerprints Proteomics Facility, Dundee University, Dundee, United Kingdom.
Institute of Developmental Biology, University of Cologne, Cologne, Germany.
Division of Developmental Biology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Medical Sciences, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Catherina G. Becker
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom.
Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom.
Peninsula College of Medicine and Dentistry (Universities of Exeter and Plymouth), John Bull Building, Research Way, Tamar Science Park, Plymouth, United Kingdom.
Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom, and Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom.
Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, United Kingdom.
Fingerprints Proteomics Facility, Dundee University, Dundee, United Kingdom.
Institute of Developmental Biology, University of Cologne, Cologne, Germany.
Division of Developmental Biology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Medical Sciences, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Brunhilde Wirth
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom.
Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom.
Peninsula College of Medicine and Dentistry (Universities of Exeter and Plymouth), John Bull Building, Research Way, Tamar Science Park, Plymouth, United Kingdom.
Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom, and Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom.
Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, United Kingdom.
Fingerprints Proteomics Facility, Dundee University, Dundee, United Kingdom.
Institute of Developmental Biology, University of Cologne, Cologne, Germany.
Division of Developmental Biology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Medical Sciences, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Thomas H. Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom.
Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Human Genetics, Institute for Genetics and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom.
Peninsula College of Medicine and Dentistry (Universities of Exeter and Plymouth), John Bull Building, Research Way, Tamar Science Park, Plymouth, United Kingdom.
Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom, and Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom.
Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, United Kingdom.
Fingerprints Proteomics Facility, Dundee University, Dundee, United Kingdom.
Institute of Developmental Biology, University of Cologne, Cologne, Germany.
Division of Developmental Biology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom.
Institute of Medical Sciences, School of Medicine and Dentistry, University of Aberdeen, Aberdeen, United Kingdom
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Paez-Colasante X, Seaberg B, Martinez TL, Kong L, Sumner CJ, Rimer M. Improvement of neuromuscular synaptic phenotypes without enhanced survival and motor function in severe spinal muscular atrophy mice selectively rescued in motor neurons. PLoS One 2013; 8:e75866. [PMID: 24086650 PMCID: PMC3781079 DOI: 10.1371/journal.pone.0075866] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 08/16/2013] [Indexed: 11/26/2022] Open
Abstract
In the inherited childhood neuromuscular disease spinal muscular atrophy (SMA), lower motor neuron death and severe muscle weakness result from the reduction of the ubiquitously expressed protein survival of motor neuron (SMN). Although SMA mice recapitulate many features of the human disease, it has remained unclear if their short lifespan and motor weakness are primarily due to cell-autonomous defects in motor neurons. Using Hb9Cre as a driver, we selectively raised SMN expression in motor neurons in conditional SMAΔ7 mice. Unlike a previous study that used choline acetyltransferase (ChATCre+) as a driver on the same mice, and another report that used Hb9Cre as a driver on a different line of conditional SMA mice, we found no improvement in survival, weight, motor behavior and presynaptic neurofilament accumulation. However, like in ChATCre+ mice, we detected rescue of endplate size and mitigation of neuromuscular junction (NMJ) denervation status. The rescue of endplate size occurred in the absence of an increase in myofiber size, suggesting endplate size is determined by the motor neuron in these animals. Real time-PCR showed that the expression of spinal cord SMN transcript was sharply reduced in Hb9Cre+ SMA mice relative to ChATCre+ SMA mice. This suggests that our lack of overall phenotypic improvement is most likely due to an unexpectedly poor recombination efficiency driven by Hb9Cre. Nonetheless, the low levels of SMN were sufficient to rescue two NMJ structural parameters indicating that these motor neuron cell autonomous phenotypes are very sensitive to changes in motoneuronal SMN levels. Our results directly suggest that even those therapeutic interventions with very modest effects in raising SMN in motor neurons may provide mitigation of neuromuscular phenotypes in SMA patients.
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Affiliation(s)
- Ximena Paez-Colasante
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M Health Science Center, Bryan, Texas, United States of America
- Texas A&M Institute for Neuroscience, Bryan, Texas, United States of America
| | - Bonnie Seaberg
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M Health Science Center, Bryan, Texas, United States of America
| | - Tara L. Martinez
- Department of Neurology, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Lingling Kong
- Department of Neurology, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Charlotte J. Sumner
- Department of Neurology, Johns Hopkins University, Baltimore, Maryland, United States of America
- Department of Neuroscience, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Mendell Rimer
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M Health Science Center, Bryan, Texas, United States of America
- Texas A&M Institute for Neuroscience, Bryan, Texas, United States of America
- * E-mail:
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Yang X, Shen H, Gao X, Zheng X, Qin R, Zhou J. Predominant expression of exon 7 skipped SMN mRNAs in lung based on analysis of transcriptome sequencing datasets. Neurol Sci 2014; 35:391-6. [DOI: 10.1007/s10072-013-1524-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 08/07/2013] [Indexed: 10/26/2022]
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Hamilton G, Gillingwater TH. Spinal muscular atrophy: going beyond the motor neuron. Trends Mol Med 2013; 19:40-50. [DOI: 10.1016/j.molmed.2012.11.002] [Citation(s) in RCA: 262] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Revised: 10/23/2012] [Accepted: 11/02/2012] [Indexed: 12/16/2022]
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