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Dysfunctional mitochondria accumulate in a skeletal muscle knockout model of Smn1, the causal gene of spinal muscular atrophy. Cell Death Dis 2023; 14:162. [PMID: 36849544 PMCID: PMC9971247 DOI: 10.1038/s41419-023-05573-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 01/07/2023] [Accepted: 01/09/2023] [Indexed: 03/01/2023]
Abstract
The approved gene therapies for spinal muscular atrophy (SMA), caused by loss of survival motor neuron 1 (SMN1), greatly ameliorate SMA natural history but are not curative. These therapies primarily target motor neurons, but SMN1 loss has detrimental effects beyond motor neurons and especially in muscle. Here we show that SMN loss in mouse skeletal muscle leads to accumulation of dysfunctional mitochondria. Expression profiling of single myofibers from a muscle specific Smn1 knockout mouse model revealed down-regulation of mitochondrial and lysosomal genes. Albeit levels of proteins that mark mitochondria for mitophagy were increased, morphologically deranged mitochondria with impaired complex I and IV activity and respiration and that produced excess reactive oxygen species accumulated in Smn1 knockout muscles, because of the lysosomal dysfunction highlighted by the transcriptional profiling. Amniotic fluid stem cells transplantation that corrects the SMN knockout mouse myopathic phenotype restored mitochondrial morphology and expression of mitochondrial genes. Thus, targeting muscle mitochondrial dysfunction in SMA may complement the current gene therapy.
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2
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Zilio E, Piano V, Wirth B. Mitochondrial Dysfunction in Spinal Muscular Atrophy. Int J Mol Sci 2022; 23:10878. [PMID: 36142791 PMCID: PMC9503857 DOI: 10.3390/ijms231810878] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 09/14/2022] [Indexed: 11/16/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a devastating neuromuscular disorder caused by recessive mutations in the SMN1 gene, globally affecting ~8-14 newborns per 100,000. The severity of the disease depends on the residual levels of functional survival of motor neuron protein, SMN. SMN is a ubiquitously expressed RNA binding protein involved in a plethora of cellular processes. In this review, we discuss the effects of SMN loss on mitochondrial functions in the neuronal and muscular systems that are the most affected in patients with spinal muscular atrophy. Our aim is to highlight how mitochondrial defects may contribute to disease progression and how restoring mitochondrial functionality may be a promising approach to develop new therapies. We also collected from previous studies a list of transcripts encoding mitochondrial proteins affected in various SMA models. Moreover, we speculate that in adulthood, when motor neurons require only very low SMN levels, the natural deterioration of mitochondria associated with aging may be a crucial triggering factor for adult spinal muscular atrophy, and this requires particular attention for therapeutic strategies.
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Affiliation(s)
- Eleonora Zilio
- Institute of Human Genetics, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
| | - Valentina Piano
- Institute of Human Genetics, 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, 50674 Cologne, Germany
- Center for Rare Diseases, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
| | - Brunhilde Wirth
- Institute of Human Genetics, 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, 50674 Cologne, Germany
- Center for Rare Diseases, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
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3
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Detering NT, Zambon A, Hensel N, Kothary R, Swoboda K, Gillingwater TH, Baranello G. 264th ENMC International Workshop: Multi-system involvement in spinal muscular atrophy Hoofddorp, the Netherlands, November 19th - 21st 2021. Neuromuscul Disord 2022; 32:697-705. [PMID: 35794048 DOI: 10.1016/j.nmd.2022.06.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Accepted: 06/16/2022] [Indexed: 11/24/2022]
Affiliation(s)
- Nora Tula Detering
- SMATHERIA gGmbH - Non-Profit Biomedical Research Institute, 30625, Hannover, Germany; Center for Systems Neuroscience (ZSN), 30559, Hannover, Germany
| | - Alberto Zambon
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health, NIHR Great Ormond Street Hospital Biomedical Research Centre & Great Ormond Street Hospital, London, UK; Neuromuscular Repair Unit, Institute of Experimental Neurology (InSpe), Division of Neuroscience, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Niko Hensel
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada, K1H 8L6
| | - Rashmi Kothary
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada, K1H 8L6; Department of Cellular and Molecular Medicine, Faculty of Medicine, and Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada, K1H 8M5
| | - Kathryn Swoboda
- Department of Neurology, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Thomas H Gillingwater
- Edinburgh Medical School: Biomedical Sciences, College of Medicine & Veterinary Medicine, University of Edinburgh, Edinburgh, UK, EH8 9AG
| | - Giovanni Baranello
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health, NIHR Great Ormond Street Hospital Biomedical Research Centre & Great Ormond Street Hospital, London, UK.
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4
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Meijboom KE, Sutton ER, McCallion E, McFall E, Anthony D, Edwards B, Kubinski S, Tapken I, Bünermann I, Hazell G, Ahlskog N, Claus P, Davies KE, Kothary R, Wood MJA, Bowerman M. Dysregulation of Tweak and Fn14 in skeletal muscle of spinal muscular atrophy mice. Skelet Muscle 2022; 12:18. [PMID: 35902978 PMCID: PMC9331072 DOI: 10.1186/s13395-022-00301-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 07/10/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is a childhood neuromuscular disorder caused by depletion of the survival motor neuron (SMN) protein. SMA is characterized by the selective death of spinal cord motor neurons, leading to progressive muscle wasting. Loss of skeletal muscle in SMA is a combination of denervation-induced muscle atrophy and intrinsic muscle pathologies. Elucidation of the pathways involved is essential to identify the key molecules that contribute to and sustain muscle pathology. The tumor necrosis factor-like weak inducer of apoptosis (TWEAK)/TNF receptor superfamily member fibroblast growth factor-inducible 14 (Fn14) pathway has been shown to play a critical role in the regulation of denervation-induced muscle atrophy as well as muscle proliferation, differentiation, and metabolism in adults. However, it is not clear whether this pathway would be important in highly dynamic and developing muscle. METHODS We thus investigated the potential role of the TWEAK/Fn14 pathway in SMA muscle pathology, using the severe Taiwanese Smn-/-; SMN2 and the less severe Smn2B/- SMA mice, which undergo a progressive neuromuscular decline in the first three post-natal weeks. We also used experimental models of denervation and muscle injury in pre-weaned wild-type (WT) animals and siRNA-mediated knockdown in C2C12 muscle cells to conduct additional mechanistic investigations. RESULTS Here, we report significantly dysregulated expression of Tweak, Fn14, and previously proposed downstream effectors during disease progression in skeletal muscle of the two SMA mouse models. In addition, siRNA-mediated Smn knockdown in C2C12 myoblasts suggests a genetic interaction between Smn and the TWEAK/Fn14 pathway. Further analyses of SMA, Tweak-/-, and Fn14-/- mice revealed dysregulated myopathy, myogenesis, and glucose metabolism pathways as a common skeletal muscle feature, providing further evidence in support of a relationship between the TWEAK/Fn14 pathway and Smn. Finally, administration of the TWEAK/Fn14 agonist Fc-TWEAK improved disease phenotypes in the two SMA mouse models. CONCLUSIONS Our study provides mechanistic insights into potential molecular players that contribute to muscle pathology in SMA and into likely differential responses of the TWEAK/Fn14 pathway in developing muscle.
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Affiliation(s)
- Katharina E Meijboom
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.,Gene Therapy Center, UMass Medical School, Worcester, USA
| | - Emma R Sutton
- School of Medicine, Keele University, Staffordshire, UK
| | - Eve McCallion
- School of Medicine, Keele University, Staffordshire, UK
| | - Emily McFall
- Regenerative Medicine Program and Department of Cellular and Molecular Medicine, Ottawa Hospital Research Institute and University of Ottawa, Ottawa, Canada
| | - Daniel Anthony
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Benjamin Edwards
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Sabrina Kubinski
- Center for Systems Neuroscience and Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany
| | - Ines Tapken
- Center for Systems Neuroscience and Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany.,SMATHERIA - Non-Profit Biomedical Research Institute, Hannover, Germany
| | - Ines Bünermann
- SMATHERIA - Non-Profit Biomedical Research Institute, Hannover, Germany
| | - Gareth Hazell
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Nina Ahlskog
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.,Department of Paediatrics, University of Oxford, Oxford, UK
| | - Peter Claus
- Center for Systems Neuroscience and Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany.,SMATHERIA - Non-Profit Biomedical Research Institute, Hannover, Germany
| | - Kay E Davies
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Rashmi Kothary
- Regenerative Medicine Program and Department of Cellular and Molecular Medicine, Ottawa Hospital Research Institute and University of Ottawa, Ottawa, Canada
| | - Matthew J A Wood
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.,Department of Paediatrics, University of Oxford, Oxford, UK
| | - Melissa Bowerman
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK. .,School of Medicine, Keele University, Staffordshire, UK. .,Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, UK.
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5
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Trimethylguanosine synthase 1 is a novel regulator of pancreatic beta-cell mass and function. J Biol Chem 2022; 298:101592. [PMID: 35041827 PMCID: PMC8861161 DOI: 10.1016/j.jbc.2022.101592] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 01/06/2022] [Accepted: 01/08/2022] [Indexed: 01/23/2023] Open
Abstract
Type 2 diabetes is a metabolic disorder associated with abnormal glucose homeostasis and is characterized by intrinsic defects in β-cell function and mass. Trimethylguanosine synthase 1 (TGS1) is an evolutionarily conserved enzyme that methylates small nuclear and nucleolar RNAs and that is involved in pre-mRNA splicing, transcription, and ribosome production. However, the role of TGS1 in β-cells and glucose homeostasis had not been explored. Here, we show that TGS1 is upregulated by insulin and upregulated in islets of Langerhans from mice exposed to a high-fat diet and in human β-cells from type 2 diabetes donors. Using mice with conditional (βTGS1KO) and inducible (MIP-CreERT-TGS1KO) TGS1 deletion, we determined that TGS1 regulates β-cell mass and function. Using unbiased approaches, we identified a link between TGS1 and endoplasmic reticulum stress and cell cycle arrest, as well as and how TGS1 regulates β-cell apoptosis. We also found that deletion of TGS1 results in an increase in the unfolded protein response by increasing XBP-1, ATF-4, and the phosphorylation of eIF2α, in addition to promoting several changes in cell cycle inhibitors and activators such as p27 and Cyclin D2. This study establishes TGS1 as a key player regulating β-cell mass and function. We propose that these observations can be used as a stepping-stone for the design of novel strategies focused on TGS1 as a therapeutic target for the treatment of diabetes.
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6
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Nutritional, Gastrointestinal and Endo-Metabolic Challenges in the Management of Children with Spinal Muscular Atrophy Type 1. Nutrients 2021; 13:nu13072400. [PMID: 34371910 PMCID: PMC8308588 DOI: 10.3390/nu13072400] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/08/2021] [Accepted: 07/10/2021] [Indexed: 12/18/2022] Open
Abstract
The management of patients with spinal muscular atrophy type 1 (SMA1) is constantly evolving. In just a few decades, the medical approach has switched from an exclusively palliative therapy to a targeted therapy, transforming the natural history of the disease, improving survival time and quality of life and creating new challenges and goals. Many nutritional problems, gastrointestinal disorders and metabolic and endocrine alterations are commonly identified in patients affected by SMA1 during childhood and adolescence. For this reason, a proper pediatric multidisciplinary approach is then required in the clinical care of these patients, with a specific focus on the prevention of most common complications. The purpose of this narrative review is to provide the clinician with a practical and usable tool about SMA1 patients care, through a comprehensive insight into the nutritional, gastroenterological, metabolic and endocrine management of SMA1. Considering the possible horizons opened thanks to new therapeutic frontiers, a nutritional and endo-metabolic surveillance is a crucial element to be considered for a proper clinical care of these patients.
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7
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Meijboom KE, Volpato V, Monzón-Sandoval J, Hoolachan JM, Hammond SM, Abendroth F, de Jong OG, Hazell G, Ahlskog N, Wood MJ, Webber C, Bowerman M. Combining multiomics and drug perturbation profiles to identify muscle-specific treatments for spinal muscular atrophy. JCI Insight 2021; 6:e149446. [PMID: 34236053 PMCID: PMC8410072 DOI: 10.1172/jci.insight.149446] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 05/17/2021] [Indexed: 12/13/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disorder caused by loss of survival motor neuron (SMN) protein. While SMN restoration therapies are beneficial, they are not a cure. We aimed to identify potentially novel treatments to alleviate muscle pathology combining transcriptomics, proteomics, and perturbational data sets. This revealed potential drug candidates for repurposing in SMA. One of the candidates, harmine, was further investigated in cell and animal models, improving multiple disease phenotypes, including lifespan, weight, and key molecular networks in skeletal muscle. Our work highlights the potential of multiple and parallel data-driven approaches for the development of potentially novel treatments for use in combination with SMN restoration therapies.
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Affiliation(s)
- Katharina E Meijboom
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.,Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Viola Volpato
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.,UK Dementia Research Institute, Cardiff University, Cardiff, United Kingdom
| | - Jimena Monzón-Sandoval
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.,UK Dementia Research Institute, Cardiff University, Cardiff, United Kingdom
| | | | - Suzan M Hammond
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.,Department of Paediatrics, John Radcliffe Hospital and.,MDUK Oxford Neuromuscular Centre, University of Oxford, United Kingdom
| | - Frank Abendroth
- Medical Research Council, Laboratory of Molecular Biology, Cambridge, United Kingdom.,Institute of Chemistry, Philipps-University of Marburg, Marburg, Germany
| | - Olivier G de Jong
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.,Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Gareth Hazell
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Nina Ahlskog
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.,Department of Paediatrics, John Radcliffe Hospital and
| | - Matthew Ja Wood
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.,Department of Paediatrics, John Radcliffe Hospital and.,MDUK Oxford Neuromuscular Centre, University of Oxford, United Kingdom
| | - Caleb Webber
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.,UK Dementia Research Institute, Cardiff University, Cardiff, United Kingdom
| | - Melissa Bowerman
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.,School of Medicine, Keele University, Staffordshire, United Kingdom.,Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom
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8
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Becker LL, Weiss C, Günther R, Hermann A, Theophil M, Hübner A, Smitka M, von der Hagen M, Kaindl AM. Evaluation of Metabolic Effects of Nusinersen in Patients with Spinal Muscular Atrophy. JOURNAL OF PEDIATRIC NEUROLOGY 2021. [DOI: 10.1055/s-0041-1731395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
AbstractNusinersen is the first disease-modifying therapy for spinal muscular atrophy (SMA), but there are few data on potential long-term endocrinological and metabolic systemic effects of this novel treatment as well as metabolic alterations in SMA itself. In this retrospective and multicentric study, we analyzed anthropometric, endocrinological, and motor function data of 81 pediatric and adult patients with SMA1 to 3 undergoing treatment with nusinersen. In 39 patients (51%), we observed a slight increase in body mass index (BMI) centiles under treatment with nusinersen, especially in patients with SMA2 and in pediatric patients between 3.1 and 12 years. A correlation to the SMN2 copy number or motor function was not found. Additionally, length centiles decreased significantly under treatment. The results of longitudinal endocrinological assessments were interpreted as not clinically significant in most patients; in three patients, the signs of an altered glucose metabolism were present. Our study indicates a putative effect of treatment with nusinersen on BMI, which might be due to a conjoint effect of weight gain and reduction of height velocity, without evidence of correlation to increased muscle function. Further studies need to address specific effects of targeted therapies such as nusinersen or onasemnogene abeparvovec on body composition including fat and muscle mass.
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Affiliation(s)
- Lena-Luise Becker
- Department of Pediatric Neurology, Charité–Universitätsmedizin, Berlin, Germany
- Center for Chronically Sick Children, Charité–Universitätsmedizin, Berlin, Germany
- Institute for Cell Biology and Neurobiology, Charité–Universitätsmedizin Berlin, Berlin, Germany
| | - Claudia Weiss
- Center for Chronically Sick Children, Charité–Universitätsmedizin, Berlin, Germany
| | - René Günther
- Department of Neurology, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Dresden, Germany
| | - Andreas Hermann
- Department of Neurology, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
- Department of Neurology, Translational Neurodegeneration Section, University Medical Center Rostock, Albrecht-Kossel, University of Rostock, Rostock, Germany
- German Center for Neurodegenerative Diseases (DZNE) Rostock, Rostock, Germany
| | - Manuela Theophil
- Department of Pediatric Neurology, DRK Kliniken Berlin Westend, Berlin, Germany
| | - Angela Hübner
- Department of Pediatrics, Technische Universität Dresden, Medizinische Fakultät Carl Gustav Carus, Dresden, Germany
| | - Martin Smitka
- Department of Pediatric Neurology, Technische Universität Dresden, Medizinische Fakultät Carl Gustav Carus, Dresden, Germany
| | - Maja von der Hagen
- Department of Pediatric Neurology, Technische Universität Dresden, Medizinische Fakultät Carl Gustav Carus, Dresden, Germany
| | - Angela M. Kaindl
- Department of Pediatric Neurology, Charité–Universitätsmedizin, Berlin, Germany
- Center for Chronically Sick Children, Charité–Universitätsmedizin, Berlin, Germany
- Institute for Cell Biology and Neurobiology, Charité–Universitätsmedizin Berlin, Berlin, Germany
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9
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Metabolic Dysfunction in Spinal Muscular Atrophy. Int J Mol Sci 2021; 22:ijms22115913. [PMID: 34072857 PMCID: PMC8198411 DOI: 10.3390/ijms22115913] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [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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10
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James R, Chaytow H, Ledahawsky LM, Gillingwater TH. Revisiting the role of mitochondria in spinal muscular atrophy. Cell Mol Life Sci 2021; 78:4785-4804. [PMID: 33821292 PMCID: PMC8195803 DOI: 10.1007/s00018-021-03819-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/22/2021] [Accepted: 03/23/2021] [Indexed: 02/07/2023]
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive motor neuron disease of variable clinical severity that is caused by mutations in the survival motor neuron 1 (SMN1) gene. Despite its name, SMN is a ubiquitous protein that functions within and outside the nervous system and has multiple cellular roles in transcription, translation, and proteostatic mechanisms. Encouragingly, several SMN-directed therapies have recently reached the clinic, albeit this has highlighted the increasing need to develop combinatorial therapies for SMA to achieve full clinical efficacy. As a subcellular site of dysfunction in SMA, mitochondria represents a relevant target for a combinatorial therapy. Accordingly, we will discuss our current understanding of mitochondrial dysfunction in SMA, highlighting mitochondrial-based pathways that offer further mechanistic insights into the involvement of mitochondria in SMA. This may ultimately facilitate translational development of targeted mitochondrial therapies for SMA. Due to clinical and mechanistic overlaps, such strategies may also benefit other motor neuron diseases and related neurodegenerative disorders.
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Affiliation(s)
- Rachel James
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Helena Chaytow
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Leire M Ledahawsky
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Thomas H Gillingwater
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK.
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK.
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11
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Glucose and lipid metabolism disorders in children and adolescents with spinal muscular atrophy types 2 and 3. Neuromuscul Disord 2021; 31:291-299. [PMID: 33685840 DOI: 10.1016/j.nmd.2021.02.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 01/20/2021] [Accepted: 02/01/2021] [Indexed: 12/25/2022]
Abstract
We aimed to estimate the prevalence of glucose and lipid metabolism disorders in children and adolescents with spinal muscular atrophy (SMA) types 2 and 3. A cross-sectional study was conducted. Medical history, anthropometric measurements, pubertal status, blood chemistry (glucose and insulin levels, lipid profile, aminotransferases, and hemoglobin A1c [HbA1c]), and liver ultrasound were obtained in all patients. Oral glucose tolerance test was performed in those with body mass index (BMI) >25th percentile or glucose or HbA1c levels in the prediabetic range. A total of 37 patients with SMA (22 type 2, 15 type 3) with a median age of 8.5 years (range 2-18.9 years) were included. Eleven patients (29.7%) met the criteria for prediabetes, but none had overt type 2 diabetes. Dyslipidemia was detected in 11 patients (29.7%), and 4 (10.8%) had hepatic steatosis on ultrasound. Sixteen patients (43.2%) had at least one abnormal finding (prediabetes, dyslipidemia, or hepatic steatosis); all but one were non-ambulatory and 12 (75%) had BMI ≥85th percentile. One young child developed fasting hypoglycemia. Our results suggest that non-ambulatory overweight/obese SMA patients are particularly prone to abnormalities in glucose and lipid metabolism. Young underweight patients might develop fasting hypoglycemia.
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12
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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] [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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13
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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] [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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14
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Ando S, Suzuki S, Okubo S, Ohuchi K, Takahashi K, Nakamura S, Shimazawa M, Fuji K, Hara H. Discovery of a CNS penetrant small molecule SMN2 splicing modulator with improved tolerability for spinal muscular atrophy. Sci Rep 2020; 10:17472. [PMID: 33060681 PMCID: PMC7562719 DOI: 10.1038/s41598-020-74346-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 09/28/2020] [Indexed: 01/08/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a motor neuron disease, typically resulting from loss-of-function mutations in the survival motor neuron 1 (SMN1) gene. Nusinersen/SPINRAZA, a splice-switching oligonucleotide that modulates SMN2 (a paralog of SMN1) splicing and consequently increases SMN protein levels, has a therapeutic effect for SMA. Previously reported small-molecule SMN2 splicing modulators such as risdiplam/EVRYSDI and its analog SMN-C3 modulate not only the splicing of SMN2 but also that of secondary splice targets, including forkhead box protein M1 (FOXM1). Through screening SMA patient-derived fibroblasts, a novel small molecule, designated TEC-1, was identified that selectively modulates SMN2 splicing over three secondary splice targets. TEC-1 did not strongly affect the splicing of FOXM1, and unlike risdiplam, did not induce micronucleus formation. In addition, TEC-1 showed higher selectively on galactosylceramidase and huntingtin gene expression compared to previously reported compounds (e.g., SMN-C3) due to off-target effects on cryptic exon inclusion and nonsense-mediated mRNA decay. Moreover, TEC-1 significantly ameliorated the disease phenotype in an SMA murine model in vivo. Thus, TEC-1 may have promising therapeutic potential for SMA, and our study demonstrates the feasibility of RNA-targeting small-molecule drug development with an improved tolerability profile.
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Affiliation(s)
- Shiori Ando
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu, 501-1196, Japan
| | | | | | - Kazuki Ohuchi
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu, 501-1196, Japan
| | - Kei Takahashi
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu, 501-1196, Japan
| | - Shinsuke Nakamura
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu, 501-1196, Japan
| | - Masamitsu Shimazawa
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu, 501-1196, Japan
| | - Koji Fuji
- Reborna Biosciences Inc., Kanagawa, 251-0012, Japan
| | - Hideaki Hara
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu, 501-1196, Japan.
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15
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Besse A, Astord S, Marais T, Roda M, Giroux B, Lejeune FX, Relaix F, Smeriglio P, Barkats M, Biferi MG. AAV9-Mediated Expression of SMN Restricted to Neurons Does Not Rescue the Spinal Muscular Atrophy Phenotype in Mice. Mol Ther 2020; 28:1887-1901. [PMID: 32470325 PMCID: PMC7403319 DOI: 10.1016/j.ymthe.2020.05.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 03/30/2020] [Accepted: 05/12/2020] [Indexed: 01/13/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disease mainly caused by mutations or deletions in the survival of motor neuron 1 (SMN1) gene and characterized by the degeneration of motor neurons and progressive muscle weakness. A viable therapeutic approach for SMA patients is a gene replacement strategy that restores functional SMN expression using adeno-associated virus serotype 9 (AAV9) vectors. Currently, systemic or intra-cerebrospinal fluid (CSF) delivery of AAV9-SMN is being explored in clinical trials. In this study, we show that the postnatal delivery of an AAV9 that expresses SMN under the control of the neuron-specific promoter synapsin selectively targets neurons without inducing re-expression in the peripheral organs of SMA mice. However, this approach is less efficient in restoring the survival and neuromuscular functions of SMA mice than the systemic or intra-CSF delivery of an AAV9 in which SMN is placed under the control of a ubiquitous promoter. This study suggests that further efforts are needed to understand the extent to which SMN is required in neurons and peripheral organs for a successful therapeutic effect.
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Affiliation(s)
- Aurore Besse
- Sorbonne Université, INSERM, Institute of Myology, Centre of Research in Myology, 75013 Paris, France
| | - Stephanie Astord
- Sorbonne Université, INSERM, Institute of Myology, Centre of Research in Myology, 75013 Paris, France
| | - Thibaut Marais
- Sorbonne Université, INSERM, Institute of Myology, Centre of Research in Myology, 75013 Paris, France
| | - Marianne Roda
- Sorbonne Université, INSERM, Institute of Myology, Centre of Research in Myology, 75013 Paris, France
| | - Benoit Giroux
- Sorbonne Université, INSERM, Institute of Myology, Centre of Research in Myology, 75013 Paris, France
| | - François-Xavier Lejeune
- Institut du Cerveau et de la Moelle épinière (ICM), Bioinformatics and Biostatistics Core Facility (iCONICS), Sorbonne Université, INSERM U1127, CNRS UMR 7225, GH Pitié-Salpêtrière, 75013 Paris, France
| | - Frederic Relaix
- Université Paris Est Créteil, INSERM, EnvA, AP-HP, 94000 Créteil, France
| | - Piera Smeriglio
- Sorbonne Université, INSERM, Institute of Myology, Centre of Research in Myology, 75013 Paris, France
| | - Martine Barkats
- Sorbonne Université, INSERM, Institute of Myology, Centre of Research in Myology, 75013 Paris, France
| | - Maria Grazia Biferi
- Sorbonne Université, INSERM, Institute of Myology, Centre of Research in Myology, 75013 Paris, France.
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16
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Houdebine L, D'Amico D, Bastin J, Chali F, Desseille C, Rumeau V, Soukkari J, Oudot C, Rouquet T, Bariohay B, Roux J, Sapaly D, Weill L, Lopes P, Djouadi F, Bezier C, Charbonnier F, Biondi O. Low-Intensity Running and High-Intensity Swimming Exercises Differentially Improve Energy Metabolism in Mice With Mild Spinal Muscular Atrophy. Front Physiol 2019; 10:1258. [PMID: 31632295 PMCID: PMC6781613 DOI: 10.3389/fphys.2019.01258] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Accepted: 09/17/2019] [Indexed: 12/13/2022] Open
Abstract
Spinal Muscular Atrophy (SMA), an autosomal recessive neurodegenerative disease characterized by the loss of spinal-cord motor-neurons, is caused by mutations on Survival-of-Motor Neuron (SMN)-1 gene. The expression of SMN2, a SMN1 gene copy, partially compensates for SMN1 disruption due to exon-7 excision in 90% of transcripts subsequently explaining the strong clinical heterogeneity. Several alterations in energy metabolism, like glucose intolerance and hyperlipidemia, have been reported in SMA at both systemic and cellular level, prompting questions about the potential role of energy homeostasis and/or production involvement in disease progression. In this context, we have recently reported the tolerance of mild SMA-like mice (SmnΔ7/Δ7; huSMN2+/+) to 10 months of low-intensity running or high-intensity swimming exercise programs, respectively involving aerobic and a mix aerobic/anaerobic muscular metabolic pathways. Here, we investigated whether those exercise-induced benefits were associated with an improvement in metabolic status in mild SMA-like mice. We showed that untrained SMA-like mice exhibited a dysregulation of lipid metabolism with an enhancement of lipogenesis and adipocyte deposits when compared to control mice. Moreover, they displayed a high oxygen consumption and energy expenditure through β-oxidation increase yet for the same levels of spontaneous activity. Interestingly, both exercises significantly improved lipid metabolism and glucose homeostasis in SMA-like mice, and enhanced oxygen consumption efficiency with the maintenance of a high oxygen consumption for higher levels of spontaneous activity. Surprisingly, more significant effects were obtained with the high-intensity swimming protocol with the maintenance of high lipid oxidation. Finally, when combining electron microscopy, respiratory chain complexes expression and enzymatic activity measurements in muscle mitochondria, we found that (1) a muscle-specific decreased in enzymatic activity of respiratory chain I, II, and IV complexes for equal amount of mitochondria and complexes expression and (2) a significant decline in mitochondrial maximal oxygen consumption, were reduced by both exercise programs. Most of the beneficial effects were obtained with the high-intensity swimming protocol. Taking together, our data support the hypothesis that active physical exercise, including high-intensity protocols, induces metabolic adaptations at both systemic and cellular levels, providing further evidence for its use in association with SMN-overexpressing therapies, in the long-term care of SMA patients.
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Affiliation(s)
- Léo Houdebine
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
| | - Domenico D'Amico
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
| | - Jean Bastin
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
| | - Farah Chali
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
| | - Céline Desseille
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
| | - Valentin Rumeau
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
| | - Judy Soukkari
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
| | - Carole Oudot
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
| | - Thaïs Rouquet
- Biomeostasis CRO, Nutritional Behavior and Metabolic Disorders, La Penne-sur-Huveaune, France
| | - Bruno Bariohay
- Biomeostasis CRO, Nutritional Behavior and Metabolic Disorders, La Penne-sur-Huveaune, France
| | - Julien Roux
- Biomeostasis CRO, Nutritional Behavior and Metabolic Disorders, La Penne-sur-Huveaune, France
| | - Delphine Sapaly
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
| | - Laure Weill
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
| | - Philippe Lopes
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France.,UFR STAPS, Université d'Evry Val-d'Essonne, Evry, France
| | - Fatima Djouadi
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
| | - Cynthia Bezier
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France.,Biophytis, Sorbonne Université, Paris, France
| | - Frédéric Charbonnier
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
| | - Olivier Biondi
- UMR-S1124, INSERM, Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, Paris, France
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17
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Deguise M, Baranello G, Mastella C, Beauvais A, Michaud J, Leone A, De Amicis R, Battezzati A, Dunham C, Selby K, Warman Chardon J, McMillan HJ, Huang Y, Courtney NL, Mole AJ, Kubinski S, Claus P, Murray LM, Bowerman M, Gillingwater TH, Bertoli S, Parson SH, Kothary R. Abnormal fatty acid metabolism is a core component of spinal muscular atrophy. Ann Clin Transl Neurol 2019; 6:1519-1532. [PMID: 31402618 PMCID: PMC6689695 DOI: 10.1002/acn3.50855] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 07/09/2019] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE Spinal muscular atrophy (SMA) is an inherited neuromuscular disorder leading to paralysis and subsequent death in young children. Initially considered a motor neuron disease, extra-neuronal involvement is increasingly recognized. The primary goal of this study was to investigate alterations in lipid metabolism in SMA patients and mouse models of the disease. METHODS We analyzed clinical data collected from a large cohort of pediatric SMA type I-III patients as well as SMA type I liver necropsy data. In parallel, we performed histology, lipid analysis, and transcript profiling in mouse models of SMA. RESULTS We identify an increased susceptibility to developing dyslipidemia in a cohort of 72 SMA patients and liver steatosis in pathological samples. Similarly, fatty acid metabolic abnormalities were present in all SMA mouse models studied. Specifically, Smn2B/- mice displayed elevated hepatic triglycerides and dyslipidemia, resembling non-alcoholic fatty liver disease (NAFLD). Interestingly, this phenotype appeared prior to denervation. INTERPRETATION This work highlights metabolic abnormalities as an important feature of SMA, suggesting implementation of nutritional and screening guidelines in patients, as such defects are likely to increase metabolic distress and cardiovascular risk. This study emphasizes the need for a systemic therapeutic approach to ensure maximal benefits for all SMA patients throughout their life.
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Affiliation(s)
- Marc‐Olivier Deguise
- Regenerative Medicine ProgramOttawa Hospital Research InstituteOttawaOntarioCanada
- Department of Cellular and Molecular MedicineUniversity of OttawaOttawaOntarioCanada
- Centre for Neuromuscular DiseaseUniversity of OttawaOttawaOntarioCanadaK1H 8M5
| | - Giovanni Baranello
- UO Neurologia dello SviluppoFondazione IRCCS Istituto Neurologico Carlo BestaMilanItaly
- The Dubowitz Neuromuscular CentreNIHR BRC University College London Great Ormond Street Institute of Child Health & Great Ormond Street HospitalLondonUnited Kingdom
| | - Chiara Mastella
- SAPRE‐UONPIA, Fondazione IRCCS Cà' Granda Ospedale Maggiore PoliclinicoMilanItaly
| | - Ariane Beauvais
- Regenerative Medicine ProgramOttawa Hospital Research InstituteOttawaOntarioCanada
| | - Jean Michaud
- Department of Pathology and Laboratory Medicine, Faculty of MedicineUniversity of OttawaOttawaOntarioCanada
| | - Alessandro Leone
- International Center for the Assessment of Nutritional Status (ICANS), Department of Food, Environmental and Nutritional Sciences (DeFENS)University of MilanMilanItaly
| | - Ramona De Amicis
- International Center for the Assessment of Nutritional Status (ICANS), Department of Food, Environmental and Nutritional Sciences (DeFENS)University of MilanMilanItaly
| | - Alberto Battezzati
- International Center for the Assessment of Nutritional Status (ICANS), Department of Food, Environmental and Nutritional Sciences (DeFENS)University of MilanMilanItaly
| | - Christopher Dunham
- Division of Anatomic PathologyChildren's and Women's Health Centre of B.CVancouverBritish ColumbiaCanada
| | - Kathryn Selby
- Division of Neurology, Department of PediatricsBC Children's HospitalVancouverBritish ColumbiaCanada
| | - Jodi Warman Chardon
- Department of Cellular and Molecular MedicineUniversity of OttawaOttawaOntarioCanada
- Centre for Neuromuscular DiseaseUniversity of OttawaOttawaOntarioCanadaK1H 8M5
- Neuroscience Program, Ottawa Hospital Research InstituteOttawaOntarioCanada
- Department of PediatricsChildren's Hospital of Eastern OntarioOttawaOntarioCanada
- Department of MedicineUniversity of OttawaOttawaOntarioCanada
| | - Hugh J. McMillan
- Children's Hospital of Eastern Ontario Research InstituteUniversity of OttawaOttawaOntarioCanada
| | - Yu‐Ting Huang
- Euan MacDonald Centre for Motor Neurone Disease ResearchUniversity of EdinburghEdinburghUnited Kingdom
- College of Medicine & Veterinary MedicineUniversity of EdinburghEdinburghUnited Kingdom
| | - Natalie L. Courtney
- Euan MacDonald Centre for Motor Neurone Disease ResearchUniversity of EdinburghEdinburghUnited Kingdom
- College of Medicine & Veterinary MedicineUniversity of EdinburghEdinburghUnited Kingdom
- Centre for Discovery Brain ScienceUniversity of EdinburghEdinburghUnited Kingdom
| | - Alannah J. Mole
- Euan MacDonald Centre for Motor Neurone Disease ResearchUniversity of EdinburghEdinburghUnited Kingdom
- College of Medicine & Veterinary MedicineUniversity of EdinburghEdinburghUnited Kingdom
- Centre for Discovery Brain ScienceUniversity of EdinburghEdinburghUnited Kingdom
| | - Sabrina Kubinski
- Institute of Neuroanatomy and Cell BiologyHannover Medical SchoolHannoverGermany
- Center of Systems NeuroscienceHannoverGermany
| | - Peter Claus
- Institute of Neuroanatomy and Cell BiologyHannover Medical SchoolHannoverGermany
- Center of Systems NeuroscienceHannoverGermany
| | - Lyndsay M. Murray
- Euan MacDonald Centre for Motor Neurone Disease ResearchUniversity of EdinburghEdinburghUnited Kingdom
- College of Medicine & Veterinary MedicineUniversity of EdinburghEdinburghUnited Kingdom
- Centre for Discovery Brain ScienceUniversity of EdinburghEdinburghUnited Kingdom
| | - Melissa Bowerman
- School of MedicineKeele UniversityStaffordshireUnited Kingdom
- Institute for Science and Technology in MedicineStoke‐on‐TrentUnited Kingdom
- Wolfson Centre for Inherited Neuromuscular DiseaseRJAH Orthopaedic HospitalOswestryUnited Kingdom
| | - Thomas H. Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease ResearchUniversity of EdinburghEdinburghUnited Kingdom
- College of Medicine & Veterinary MedicineUniversity of EdinburghEdinburghUnited Kingdom
| | - Simona Bertoli
- International Center for the Assessment of Nutritional Status (ICANS), Department of Food, Environmental and Nutritional Sciences (DeFENS)University of MilanMilanItaly
| | - Simon H. Parson
- Euan MacDonald Centre for Motor Neurone Disease ResearchUniversity of EdinburghEdinburghUnited Kingdom
- Institute of Medical SciencesUniversity of AberdeenAberdeenUnited Kingdom
| | - Rashmi Kothary
- Regenerative Medicine ProgramOttawa Hospital Research InstituteOttawaOntarioCanada
- Department of Cellular and Molecular MedicineUniversity of OttawaOttawaOntarioCanada
- Centre for Neuromuscular DiseaseUniversity of OttawaOttawaOntarioCanadaK1H 8M5
- Department of MedicineUniversity of OttawaOttawaOntarioCanada
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18
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Qian X, Du Y, Jiang G, Lin F, Yao L. Survival Motor Neuron (SMN) Protein Insufficiency Exacerbates Renal Ischemia/Reperfusion Injury. Front Physiol 2019; 10:559. [PMID: 31139093 PMCID: PMC6527877 DOI: 10.3389/fphys.2019.00559] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 04/24/2019] [Indexed: 12/14/2022] Open
Abstract
The survival of motor neuron (SMN) protein is ubiquitously involved in spliceosome assembly and ribonucleoprotein biogenesis. SMN protein is expressed in kidney and can affect cell death processes. However, the role of SMN in acute kidney injury (AKI) is largely unknown. In the current study, we found that the expression of SMN in the kidney was significantly reduced in both clinical ischemic AKI and a mouse model of renal ischemia-reperfusion injury (IRI). We then used SMN heterozygous knockout (SMN+/-) mice and found that the declines in renal function, tubular injury, and tubular cell apoptosis after experimental IRI were significantly more severe in SMN+/- mice than those in their wild-type littermates. Concomitantly, the canonical transcription factor nuclear factor-κb (NFκb) signaling was enhanced in ischemic SMN+/- mice. In vitro, cobalt dichloride (CoCl2) treatment reduced SMN expression in proximal tubular epithelial cells. In addition, CoCl2-induced apoptosis and activation of NFκb signaling pathway were enhanced by transient transfection of a small-interfering RNA (siRNA) against SMN while attenuated by transient transfection of a full-length SMN plasmid. Taken together, this study for the first time supported the protective role of SMN in ischemic AKI.
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Affiliation(s)
- Xiaoqian Qian
- Renal Division, Department of Internal Medicine, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Centre for Rare Disease, Shanghai, China
| | - Yichao Du
- Sichuan Provincial Academician (Expert) Workstation, The Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Gengru Jiang
- Renal Division, Department of Internal Medicine, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Centre for Rare Disease, Shanghai, China
| | - Fujun Lin
- Renal Division, Department of Internal Medicine, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Centre for Rare Disease, Shanghai, China
| | - Lei Yao
- Sichuan Provincial Academician (Expert) Workstation, The Affiliated Hospital of Southwest Medical University, Luzhou, China
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19
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Sturm S, Günther A, Jaber B, Jordan P, Al Kotbi N, Parkar N, Cleary Y, Frances N, Bergauer T, Heinig K, Kletzl H, Marquet A, Ratni H, Poirier A, Müller L, Czech C, Khwaja O. A phase 1 healthy male volunteer single escalating dose study of the pharmacokinetics and pharmacodynamics of risdiplam (RG7916, RO7034067), a SMN2 splicing modifier. Br J Clin Pharmacol 2018; 85:181-193. [PMID: 30302786 DOI: 10.1111/bcp.13786] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 08/29/2018] [Accepted: 09/09/2018] [Indexed: 12/22/2022] Open
Abstract
AIMS Risdiplam (RG7916, RO7034067) is an orally administered, centrally and peripherally distributed, survival of motor neuron 2 (SMN2) mRNA splicing modifier for the treatment of spinal muscular atrophy (SMA). The objectives of this entry-into-human study were to assess the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics of risdiplam, and the effect of the strong CYP3A inhibitor itraconazole on the PK of risdiplam in healthy male volunteers. METHODS Part 1 had a randomized, double-blind, adaptive design with 25 subjects receiving single ascending oral doses of risdiplam (ranging from 0.6-18.0 mg, n = 18) or placebo (n = 7). A Bayesian framework was applied to estimate risdiplam's effect on SMN2 mRNA. The effect of multiple doses of itraconazole on the PK of risdiplam was also assessed using a two-period cross-over design (n = 8). RESULTS Risdiplam in the fasted or fed state was well tolerated. Risdiplam exhibited linear PK over the dose range with a multi-phasic decline with a mean terminal half-life of 40-69 h. Food had no relevant effect, and itraconazole had only a minor effect on plasma PK indicating a low fraction of risdiplam metabolized by CYP3A. The highest tested dose of 18.0 mg risdiplam led to approximately 41% (95% confidence interval 27-55%) of the estimated maximum increase in SMN2 mRNA. CONCLUSIONS Risdiplam was well tolerated and proof of mechanism was demonstrated by the intended shift in SMN2 splicing towards full-length SMN2 mRNA. Based on these data, Phase 2/3 studies of risdiplam in patients with SMA are now ongoing.
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20
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Using Systems Biology and Mathematical Modeling Approaches in the Discovery of Therapeutic Targets for Spinal Muscular Atrophy. ADVANCES IN NEUROBIOLOGY 2018. [PMID: 30334226 DOI: 10.1007/978-3-319-94593-4_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
Systems biology uses a combination of experimental and mathematical approaches to investigate the complex and dynamic interactions with a given system or biological process. Systems biology integrates genetics, signal transduction, biochemistry and cell biology with mathematical modeling. It can be used to identify novel pathways implicated in diseases as well as to understand the mechanisms by which a specific gene is regulated. This review describes the development of mathematical models for the regulation of an endogenous modifier gene, SMN2, in spinal muscular atrophy-an early-onset motor neuron disease that is a leading genetic cause of infant mortality worldwide-by cAMP signaling. These mathematical models not only can aid in understanding how SMN2 expression is regulated but they can also be used to examine the best ways to manipulate cAMP signaling to maximally increase SMN2 expression. These models will lead to the development of therapeutic strategies for treating SMA. This systems biology approach can also be applied to other neurological diseases, particularly those in which a disease-causing gene or a modifier gene has been identified.
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21
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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: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [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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22
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Jha NN, Kim JK, Monani UR. Motor neuron biology and disease: A current perspective on infantile-onset spinal muscular atrophy. FUTURE NEUROLOGY 2018; 13:161-172. [PMID: 31396020 DOI: 10.2217/fnl-2018-0008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Infantile-onset spinal muscular atrophy (SMA) is a prototypical disease in which to investigate selective neurodegenerative phenotypes. Caused by low levels of the ubiquitously expressed Survival Motor Neuron (SMN) protein, the disease mainly targets the spinal motor neurons. This selective phenotype remains largely unexplained, but has not hindered the development of SMN repletion as a means to a treatment. Here we chronicle recent advances in the area of SMA biology. We provide a brief background to the disease, highlight major advances that have shaped our current understanding of SMA, trace efforts to treat the condition, discuss the outcome of two promising new therapies and conclude by considering contemporary as well as new challenges stemming from recent successes within the field.
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Affiliation(s)
- Narendra N Jha
- Department of Pathology & Cell Biology, 630 W. 168 St., Columbia University Medical Center, New York, NY 10032.,Center for Motor Neuron Biology & Disease, 630 W. 168 St., Columbia University Medical Center, New York, NY 10032
| | - Jeong-Ki Kim
- Department of Pathology & Cell Biology, 630 W. 168 St., Columbia University Medical Center, New York, NY 10032.,Center for Motor Neuron Biology & Disease, 630 W. 168 St., Columbia University Medical Center, New York, NY 10032
| | - Umrao R Monani
- Department of Pathology & Cell Biology, 630 W. 168 St., Columbia University Medical Center, New York, NY 10032.,Department of Neurology, 630 W. 168 St., Columbia University Medical Center, New York, NY 10032.,Center for Motor Neuron Biology & Disease, 630 W. 168 St., Columbia University Medical Center, New York, NY 10032
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23
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Faber I, Martinez ARM, de Rezende TJR, Martins CR, Martins MP, Lourenço CM, Marques W, Montecchiani C, Orlacchio A, Pedroso JL, Barsottini OGP, Lopes-Cendes Í, França MC. SPG11 mutations cause widespread white matter and basal ganglia abnormalities, but restricted cortical damage. Neuroimage Clin 2018; 19:848-857. [PMID: 29946510 PMCID: PMC6008284 DOI: 10.1016/j.nicl.2018.05.031] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Revised: 05/20/2018] [Accepted: 05/22/2018] [Indexed: 12/12/2022]
Abstract
SPG11 mutations are the major cause of autosomal recessive Hereditary Spastic Paraplegia. The disease has a wide phenotypic variability indicating many regions of the nervous system besides the corticospinal tract are affected. Despite this, anatomical and phenotypic characterization is restricted. In the present study, we investigate the anatomical abnormalities related to SPG11 mutations and how they relate to clinical and cognitive measures. Moreover, we aim to depict how the disease course influences the regions affected, unraveling different susceptibility of specific neuronal populations. We performed clinical and paraclinical studies encompassing neuropsychological, neuroimaging, and neurophysiological tools in a cohort of twenty-five patients and age matched controls. We assessed cortical thickness (FreeSurfer software), deep grey matter volumes (T1-MultiAtlas tool), white matter microstructural damage (DTI-MultiAtlas) and spinal cord morphometry (Spineseg software) on a 3 T MRI scan. Mean age and disease duration were 29 and 13.2 years respectively. Sixty-four percent of the patients were wheelchair bound while 84% were demented. We were able to unfold a diffuse pattern of white matter integrity loss as well as basal ganglia and spinal cord atrophy. Such findings contrasted with a restricted pattern of cortical thinning (motor, limbic and parietal cortices). Electromyography revealed motor neuronopathy affecting 96% of the probands. Correlations with disease duration pointed towards a progressive degeneration of multiple grey matter structures and spinal cord, but not of the white matter. SPG11-related hereditary spastic paraplegia is characterized by selective neuronal vulnerability, in which a precocious and widespread white matter involvement is later followed by a restricted but clearly progressive grey matter degeneration.
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Key Words
- ACE-R, Addenbrooke's Cognitive Examination Revised
- ALS, amyotrophic lateral sclerosis
- CA, cord area
- CE, cord eccentricity
- CMAP, compound muscle action potential
- CST, corticospinal tract
- Complicated hereditary spastic paraplegia
- DTI, diffusion tensor imaging
- FA, fractional anisotropy
- GM, grey matter
- Grey matter
- HSP, hereditary spastic paraplegia
- LH, left hemisphere
- MD, mean diffusivity
- MOCA, Montreal cognitive assessment
- Motor neuron disorder
- NPI, neuropsychiatric inventory
- PNP, sensory-motor polyneuropathy
- PNS, peripheral nervous system
- RH, right hemisphere
- ROI, region of interest
- SC, spinal cord
- SNAP, sensory nerve action potential
- SPG11
- SPRS, Spastic Paraplegia Rating Scale
- STS, cortex adjacent to the superior temporal sulcus
- Spinal cord
- Thinning of the corpus callosum
- WES, whole exome sequencing
- WM, white matter
- White matter
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Affiliation(s)
- Ingrid Faber
- Department of Neurology, University of Campinas (UNICAMP), Campinas, Brazil
| | | | | | | | | | | | - Wilson Marques
- Department of Neurology, University of São Paulo (USP-RP), Ribeirão Preto, Brazil
| | - Celeste Montecchiani
- Laboratorio di Neurogenetica, Centro Europeo di Ricerca sul Cervello (CERC) - Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Santa Lucia, Rome, Italy
| | - Antonio Orlacchio
- Laboratorio di Neurogenetica, Centro Europeo di Ricerca sul Cervello (CERC) - Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Santa Lucia, Rome, Italy; Dipartimento di Scienze Chirurgiche e Biomediche, Università di Perugia, Perugia, Italy
| | - Jose Luiz Pedroso
- Department of Neurology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
| | | | - Íscia Lopes-Cendes
- Department of Medical Genetics, University of Campinas (UNICAMP), Campinas, Brazil
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24
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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] [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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25
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Walter LM, Deguise MO, Meijboom KE, Betts CA, Ahlskog N, van Westering TLE, Hazell G, McFall E, Kordala A, Hammond SM, Abendroth F, Murray LM, Shorrock HK, Prosdocimo DA, Haldar SM, Jain MK, Gillingwater TH, Claus P, Kothary R, Wood MJA, Bowerman M. Interventions Targeting Glucocorticoid-Krüppel-like Factor 15-Branched-Chain Amino Acid Signaling Improve Disease Phenotypes in Spinal Muscular Atrophy Mice. EBioMedicine 2018; 31:226-242. [PMID: 29735415 PMCID: PMC6013932 DOI: 10.1016/j.ebiom.2018.04.024] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Revised: 04/15/2018] [Accepted: 04/26/2018] [Indexed: 01/01/2023] Open
Abstract
The circadian glucocorticoid-Krüppel-like factor 15-branched-chain amino acid (GC-KLF15-BCAA) signaling pathway is a key regulatory axis in muscle, whose imbalance has wide-reaching effects on metabolic homeostasis. Spinal muscular atrophy (SMA) is a neuromuscular disorder also characterized by intrinsic muscle pathologies, metabolic abnormalities and disrupted sleep patterns, which can influence or be influenced by circadian regulatory networks that control behavioral and metabolic rhythms. We therefore set out to investigate the contribution of the GC-KLF15-BCAA pathway in SMA pathophysiology of Taiwanese Smn−/−;SMN2 and Smn2B/− mouse models. We thus uncover substantial dysregulation of GC-KLF15-BCAA diurnal rhythmicity in serum, skeletal muscle and metabolic tissues of SMA mice. Importantly, modulating the components of the GC-KLF15-BCAA pathway via pharmacological (prednisolone), genetic (muscle-specific Klf15 overexpression) and dietary (BCAA supplementation) interventions significantly improves disease phenotypes in SMA mice. Our study highlights the GC-KLF15-BCAA pathway as a contributor to SMA pathogenesis and provides several treatment avenues to alleviate peripheral manifestations of the disease. The therapeutic potential of targeting metabolic perturbations by diet and commercially available drugs could have a broader implementation across other neuromuscular and metabolic disorders characterized by altered GC-KLF15-BCAA signaling. SMA is a neuromuscular disease characterized by motoneuron loss, muscle abnormalities and metabolic perturbations. The regulatory GC-KLF15-BCAA pathway is dysregulated in serum and skeletal muscle of SMA mice during disease progression. Modulating GC-KLF15-BCAA signaling by pharmacological, dietary and genetic interventions improves phenotype of SMA mice.
Spinal muscular atrophy (SMA) is a devastating and debilitating childhood genetic disease. Although nerve cells are mainly affected, muscle is also severely impacted. The normal communication between the glucocorticoid (GC) hormone, the protein KLF15 and the dietary branched-chain amino acids (BCAAs) maintains muscle and whole-body health. In this study, we identified an abnormal activity of GC-KLF15- BCAA in blood and muscle of SMA mice. Importantly, targeting GC-KLF15-BCAA activity with an existing drug or a specific diet improved disease progression in SMA mice. Our research uncovers GCs, KLF15 and BCAAs as therapeutic targets to ameliorate SMA muscle and whole-body health.
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Affiliation(s)
- Lisa M Walter
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany; Center of Systems Neuroscience, Hannover, Germany
| | - Marc-Olivier Deguise
- Ottawa Hospital Research Institute, Regenerative Medicine Program, Ottawa, ON, Canada; Department of Medicine and Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Katharina E Meijboom
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Corinne A Betts
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Nina Ahlskog
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Tirsa L E van Westering
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Gareth Hazell
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Emily McFall
- Ottawa Hospital Research Institute, Regenerative Medicine Program, Ottawa, ON, Canada; Department of Medicine and Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Anna Kordala
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Suzan M Hammond
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Frank Abendroth
- Medical Research Council, Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Lyndsay M Murray
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom; Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Hannah K Shorrock
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom; Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Domenick A Prosdocimo
- Case Cardiovascular Research Institute, Case Western Reserve University School of Medicine, University Hospitals Case Medical Center, Cleveland, OH, USA
| | - Saptarsi M Haldar
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA, USA; Department of Medicine, Division of Cardiology University of California, San Francisco, CA, USA
| | - Mukesh K Jain
- Case Cardiovascular Research Institute, Case Western Reserve University School of Medicine, University Hospitals Case Medical Center, Cleveland, OH, USA
| | - Thomas H Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom; Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Peter Claus
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany; Center of Systems Neuroscience, Hannover, Germany
| | - Rashmi Kothary
- Ottawa Hospital Research Institute, Regenerative Medicine Program, Ottawa, ON, Canada; Department of Medicine and Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Matthew J A Wood
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Melissa Bowerman
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.
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26
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Bowerman M, Becker CG, Yáñez-Muñoz RJ, Ning K, Wood MJA, Gillingwater TH, Talbot K. Therapeutic strategies for spinal muscular atrophy: SMN and beyond. Dis Model Mech 2018; 10:943-954. [PMID: 28768735 PMCID: PMC5560066 DOI: 10.1242/dmm.030148] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a devastating neuromuscular disorder characterized by loss of motor neurons and muscle atrophy, generally presenting in childhood. SMA is caused by low levels of the survival motor neuron protein (SMN) due to inactivating mutations in the encoding gene SMN1. A second duplicated gene, SMN2, produces very little but sufficient functional protein for survival. Therapeutic strategies to increase SMN are in clinical trials, and the first SMN2-directed antisense oligonucleotide (ASO) therapy has recently been licensed. However, several factors suggest that complementary strategies may be needed for the long-term maintenance of neuromuscular and other functions in SMA patients. Pre-clinical SMA models demonstrate that the requirement for SMN protein is highest when the structural connections of the neuromuscular system are being established, from late fetal life throughout infancy. Augmenting SMN may not address the slow neurodegenerative process underlying progressive functional decline beyond childhood in less severe types of SMA. Furthermore, individuals receiving SMN-based treatments may be vulnerable to delayed symptoms if rescue of the neuromuscular system is incomplete. Finally, a large number of older patients living with SMA do not fulfill the present criteria for inclusion in gene therapy and ASO clinical trials, and may not benefit from SMN-inducing treatments. Therefore, a comprehensive whole-lifespan approach to SMA therapy is required that includes both SMN-dependent and SMN-independent strategies that treat the CNS and periphery. Here, we review the range of non-SMN pathways implicated in SMA pathophysiology and discuss how various model systems can serve as valuable tools for SMA drug discovery. Summary: Translational research for spinal muscular atrophy (SMA) should address the development of non-CNS and survival motor neuron (SMN)-independent therapeutic approaches to complement and enhance the benefits of CNS-directed and SMN-dependent therapies.
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Affiliation(s)
- Melissa Bowerman
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | - Catherina G Becker
- Euan MacDonald Centre for Motor Neurone Disease Research and Centre for Neuroregeneration, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Rafael J Yáñez-Muñoz
- AGCTlab.org, Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway, University of London, Egham Hill, Egham, Surrey TW20 0EX, UK
| | - Ke Ning
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield S10 2HQ, UK
| | - Matthew J A Wood
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | - Thomas H Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research and Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Kevin Talbot
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
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27
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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: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [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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28
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Alternative mRNA Splicing in the Pathogenesis of Obesity. Int J Mol Sci 2018; 19:ijms19020632. [PMID: 29473878 PMCID: PMC5855854 DOI: 10.3390/ijms19020632] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 02/21/2018] [Accepted: 02/21/2018] [Indexed: 12/22/2022] Open
Abstract
Alternative mRNA splicing is an important mechanism in expansion of proteome diversity by production of multiple protein isoforms. However, emerging evidence indicates that only a limited number of annotated protein isoforms by alternative splicing are detected, and the coding sequence of alternative splice variants usually is only slightly different from that of the canonical sequence. Nevertheless, mis-splicing is associated with a large array of human diseases. Previous reviews mainly focused on hereditary and somatic mutations in cis-acting RNA sequence elements and trans-acting splicing factors. The importance of environmental perturbations contributed to mis-splicing is not assessed. As significant changes in exon skipping and splicing factors expression levels are observed with diet-induced obesity, this review focuses on several well-known alternatively spliced metabolic factors and discusses recent advances in the regulation of the expressions of splice variants under the pathophysiological conditions of obesity. The potential of targeting the alternative mRNA mis-splicing for obesity-associated diseases therapies will also be discussed.
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29
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Abstract
PURPOSE OF REVIEW Spinal muscular atrophy (SMA) is an inherited childhood neurodegenerative disorder caused by ubiquitous deficiency of the survival motor neuron (SMN) protein - the hallmarks of which are the selective loss of motor neurons and skeletal muscle atrophy. Here, we highlight recent progress in the understanding of SMA pathology and in the development of therapeutic approaches for its treatment. RECENT FINDINGS Phenotypic characterization of mouse models of the disease, combined with analysis of SMN restoration or depletion in a spatially and temporally controlled manner, has yielded key insights into the normal requirement of SMN and SMA pathophysiology. Increasing evidence indicates a higher demand for SMN during neuromuscular development and extends the pathogenic effects of SMN deficiency beyond motor neurons to include additional cells both within and outside the nervous system. These findings have been paralleled by preclinical development of powerful approaches for increasing SMN expression through gene therapy or splicing modulation that are now in human trials. SUMMARY Along with the availability of SMN-upregulating drugs, identification of the specific cell types in which SMN deficiency induces the disease and delineation of the window of opportunity for effective treatment are key advances in the ongoing path to SMA therapy.
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30
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Singh RN, Singh NN. Mechanism of Splicing Regulation of Spinal Muscular Atrophy Genes. ADVANCES IN NEUROBIOLOGY 2018; 20:31-61. [PMID: 29916015 DOI: 10.1007/978-3-319-89689-2_2] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Spinal muscular atrophy (SMA) is one of the major genetic disorders associated with infant mortality. More than 90% cases of SMA result from deletions or mutations of 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. However, correction of SMN2 exon 7 splicing has proven to confer therapeutic benefits in SMA patients. The only approved drug for SMA is an antisense oligonucleotide (Spinraza™/Nusinersen), which corrects SMN2 exon 7 splicing by blocking intronic splicing silencer N1 (ISS-N1) located immediately downstream of exon 7. ISS-N1 is a complex regulatory element encompassing overlapping negative motifs and sequestering a cryptic splice site. More than 40 protein factors have been implicated in the regulation of SMN exon 7 splicing. There is evidence to support that multiple exons of SMN are alternatively spliced during oxidative stress, which is associated with a growing number of pathological conditions. Here, we provide the most up to date account of the mechanism of splicing regulation of the SMN genes.
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Affiliation(s)
- Ravindra N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA, USA.
| | - Natalia N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA, USA
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31
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Bowerman M, Murray LM, Scamps F, Schneider BL, Kothary R, Raoul C. Pathogenic commonalities between spinal muscular atrophy and amyotrophic lateral sclerosis: Converging roads to therapeutic development. Eur J Med Genet 2017; 61:685-698. [PMID: 29313812 DOI: 10.1016/j.ejmg.2017.12.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 10/04/2017] [Accepted: 12/03/2017] [Indexed: 12/12/2022]
Abstract
Spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS) are the two most common motoneuron disorders, which share typical pathological hallmarks while remaining genetically distinct. Indeed, SMA is caused by deletions or mutations in the survival motor neuron 1 (SMN1) gene whilst ALS, albeit being mostly sporadic, can also be caused by mutations within genes, including superoxide dismutase 1 (SOD1), Fused in Sarcoma (FUS), TAR DNA-binding protein 43 (TDP-43) and chromosome 9 open reading frame 72 (C9ORF72). However, it has come to light that these two diseases may be more interlinked than previously thought. Indeed, it has recently been found that FUS directly interacts with an Smn-containing complex, mutant SOD1 perturbs Smn localization, Smn depletion aggravates disease progression of ALS mice, overexpression of SMN in ALS mice significantly improves their phenotype and lifespan, and duplications of SMN1 have been linked to sporadic ALS. Beyond genetic interactions, accumulating evidence further suggests that both diseases share common pathological identities such as intrinsic muscle defects, neuroinflammation, immune organ dysfunction, metabolic perturbations, defects in neuron excitability and selective motoneuron vulnerability. Identifying common molecular effectors that mediate shared pathologies in SMA and ALS would allow for the development of therapeutic strategies and targeted gene therapies that could potentially alleviate symptoms and be equally beneficial in both disorders. In the present review, we will examine our current knowledge of pathogenic commonalities between SMA and ALS, and discuss how furthering this understanding can lead to the establishment of novel therapeutic approaches with wide-reaching impact on multiple motoneuron diseases.
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Affiliation(s)
- Melissa Bowerman
- School of Medicine, Keele University, Staffordshire, United Kingdom; Institute for Science and Technology in Medicine, Stoke-on-Trent, United Kingdom; Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom
| | - Lyndsay M Murray
- Euan McDonald Centre for Motor Neuron Disease Research and Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Frédérique Scamps
- The Institute for Neurosciences of Montpellier, Inserm UMR1051, Univ Montpellier, Saint Eloi Hospital, Montpellier, France
| | - Bernard L Schneider
- Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Rashmi Kothary
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Canada; Departments of Medicine and Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
| | - Cédric Raoul
- The Institute for Neurosciences of Montpellier, Inserm UMR1051, Univ Montpellier, Saint Eloi Hospital, Montpellier, France.
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Mercuri E, Finkel RS, Muntoni F, Wirth B, Montes J, Main M, Mazzone ES, Vitale M, Snyder B, Quijano-Roy S, Bertini E, Davis RH, Meyer OH, Simonds AK, Schroth MK, Graham RJ, Kirschner J, Iannaccone ST, Crawford TO, Woods S, Qian Y, Sejersen T. Diagnosis and management of spinal muscular atrophy: Part 1: Recommendations for diagnosis, rehabilitation, orthopedic and nutritional care. Neuromuscul Disord 2017; 28:103-115. [PMID: 29290580 DOI: 10.1016/j.nmd.2017.11.005] [Citation(s) in RCA: 540] [Impact Index Per Article: 77.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Revised: 11/06/2017] [Accepted: 11/13/2017] [Indexed: 01/02/2023]
Abstract
Spinal muscular atrophy (SMA) is a severe neuromuscular disorder due to a defect in the survival motor neuron 1 (SMN1) gene. Its incidence is approximately 1 in 11,000 live births. In 2007, an International Conference on the Standard of Care for SMA published a consensus statement on SMA standard of care that has been widely used throughout the world. Here we report a two-part update of the topics covered in the previous recommendations. In part 1 we present the methods used to achieve these recommendations, and an update on diagnosis, rehabilitation, orthopedic and spinal management; and nutritional, swallowing and gastrointestinal management. Pulmonary management, acute care, other organ involvement, ethical issues, medications, and the impact of new treatments for SMA are discussed in part 2.
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Affiliation(s)
- Eugenio Mercuri
- Paediatric Neurology Unit, Catholic University, Rome, Italy; Centro Clinico Nemo, Policlinico Gemelli, Rome, Italy.
| | - Richard S Finkel
- Nemours Children's Hospital, University of Central Florida College of Medicine, Orlando, FL, USA
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health & Great Ormond Street Hospital, London, UK
| | - Brunhilde Wirth
- Institute of Human Genetics, Center for Molecular Medicine, Center for Rare Diseases and Institute for Genetics, University of Cologne, Germany
| | - Jacqueline Montes
- Departments of Rehabilitation and Regenerative Medicine and Neurology, Columbia University Medical Center, New York, NY, USA
| | - Marion Main
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health & Great Ormond Street Hospital, London, UK
| | - Elena S Mazzone
- Paediatric Neurology Unit, Catholic University, Rome, Italy; Centro Clinico Nemo, Policlinico Gemelli, Rome, Italy
| | - Michael Vitale
- Department of Orthopaedic Surgery, Columbia University Medical Center, New York, NY, USA
| | - Brian Snyder
- Department of Orthopaedic Surgery, Children's Hospital, Harvard Medical School, Boston, USA
| | - Susana Quijano-Roy
- Assistance Publique des Hôpitaux de Paris (AP-HP), Unit of Neuromuscular Disorders, Department of Pediatric Intensive Care, Neurology and Rehabilitation, Hôpital Raymond Poincaré, Garches, France; Hôpitaux Universitaires Paris-Ile-de-France Ouest, INSERM U 1179, University of Versailles Saint-Quentin-en-Yvelines (UVSQ), Paris, France
| | - Enrico Bertini
- Unit of Neuromuscular & Neurodegenerative Disorders, Dept of Neurosciences & Neurorehabilitation, Bambino Gesù Children's Research Hospital, Rome, Italy
| | | | - Oscar H Meyer
- Division of Pulmonology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Anita K Simonds
- NIHR Respiratory Biomedical Research Unit, Royal Brompton & Harefield NHS Foundation Trust, London, UK
| | - Mary K Schroth
- Division of Pediatric Pulmonary, Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, American Family Children's Hospital, Madison, WI, USA
| | - Robert J Graham
- Division of Critical Care, Dept of Anesthesiology, Perioperative & Pain Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Janbernd Kirschner
- Department of Neuropediatrics and Muscle Disorders, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Susan T Iannaccone
- Departments of Pediatrics and Neurology and Neurotherapeutics, Division of Pediatric Neurology, University of Texas Southwestern Medical Center and Children's Medical Center Dallas, USA
| | - Thomas O Crawford
- Department of Neurology, Johns Hopkins University, Baltimore, MD, USA
| | - Simon Woods
- Policy Ethics and Life Sciences Research Centre, Newcastle University, Newcastle, UK
| | | | - Thomas Sejersen
- Department of Women's and Children's Health, Paediatric Neurology, Karolinska Institute, Stockholm, Sweden
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O'Meara RW, Cummings SE, De Repentigny Y, McFall E, Michalski JP, Deguise MO, Gibeault S, Kothary R. Oligodendrocyte development and CNS myelination are unaffected in a mouse model of severe spinal muscular atrophy. Hum Mol Genet 2017; 26:282-292. [PMID: 28069797 DOI: 10.1093/hmg/ddw385] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 11/04/2016] [Indexed: 11/12/2022] Open
Abstract
The childhood neurodegenerative disease spinal muscular atrophy (SMA) is caused by loss-of-function mutations or deletions in the Survival Motor Neuron 1 (SMN1) gene resulting in insufficient levels of survival motor neuron (SMN) protein. Classically considered a motor neuron disease, increasing evidence now supports SMA as a multi-system disorder with phenotypes discovered in cortical neuron, astrocyte, and Schwann cell function within the nervous system. In this study, we sought to determine whether Smn was critical for oligodendrocyte (OL) development and central nervous system myelination. A mouse model of severe SMA was used to assess OL growth, migration, differentiation and myelination. All aspects of OL development and function studied were unaffected by Smn depletion. The tremendous impact of Smn depletion on a wide variety of other cell types renders the OL response unique. Further investigation of the OLs derived from SMA models may reveal disease modifiers or a compensatory mechanism allowing these cells to flourish despite the reduced levels of this multifunctional protein.
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Affiliation(s)
- Ryan W O'Meara
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada.,University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
| | - Sarah E Cummings
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada.,University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
| | - Yves De Repentigny
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
| | - Emily McFall
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
| | - John-Paul Michalski
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada.,University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
| | - Marc-Olivier Deguise
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada.,University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
| | - Sabrina Gibeault
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
| | - Rashmi Kothary
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada.,University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada.,Department of Medicine, University of Ottawa, Ottawa, ON, Canada
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34
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Deguise MO, De Repentigny Y, McFall E, Auclair N, Sad S, Kothary R. Immune dysregulation may contribute to disease pathogenesis in spinal muscular atrophy mice. Hum Mol Genet 2017; 26:801-819. [PMID: 28108555 PMCID: PMC5409095 DOI: 10.1093/hmg/ddw434] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 12/16/2016] [Indexed: 01/21/2023] Open
Abstract
Spinal muscular atrophy (SMA) has long been solely considered a neurodegenerative disorder. However, recent work has highlighted defects in many other cell types that could contribute to disease aetiology. Interestingly, the immune system has never been extensively studied in SMA. Defects in lymphoid organs could exacerbate disease progression by neuroinflammation or immunodeficiency. Smn depletion led to severe alterations in the thymus and spleen of two different mouse models of SMA. The spleen from Smn depleted mice was dramatically smaller at a very young age and its histological architecture was marked by mislocalization of immune cells in the Smn2B/- model mice. In comparison, the thymus was relatively spared in gross morphology but showed many histological alterations including cortex thinning in both mouse models at symptomatic ages. Thymocyte development was also impaired as evidenced by abnormal population frequencies in the Smn2B/- thymus. Cytokine profiling revealed major changes in different tissues of both mouse models. Consistent with our observations, we found that survival motor neuron (Smn) protein levels were relatively high in lymphoid organs compared to skeletal muscle and spinal cord during postnatal development in wild type mice. Genetic introduction of one copy of the human SMN2 transgene was enough to rescue splenic and thymic defects in Smn2B/- mice. Thus, Smn is required for the normal development of lymphoid organs, and altered immune function may contribute to SMA disease pathogenesis.
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Affiliation(s)
- Marc-Olivier Deguise
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada K1H 8L6.,Department of Cellular and Molecular Medicine.,Centre for Neuromuscular Disease, University of Ottawa
| | - Yves De Repentigny
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada K1H 8L6.,Centre for Neuromuscular Disease, University of Ottawa
| | - Emily McFall
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada K1H 8L6.,Centre for Neuromuscular Disease, University of Ottawa
| | - Nicole Auclair
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada K1H 8L6.,Faculty of Science, University of Ottawa, Ottawa, Ontario, Canada, K1N 9B4
| | - Subash Sad
- Department of Biochemistry, Microbiology, and Immunology
| | - Rashmi Kothary
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada K1H 8L6.,Department of Cellular and Molecular Medicine.,Centre for Neuromuscular Disease, University of Ottawa.,Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada K1H 8M5
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35
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Khairallah MT, Astroski J, Custer SK, Androphy EJ, Franklin CL, Lorson CL. SMN deficiency negatively impacts red pulp macrophages and spleen development in mouse models of spinal muscular atrophy. Hum Mol Genet 2017; 26:932-941. [PMID: 28062667 DOI: 10.1093/hmg/ddx008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 01/03/2017] [Indexed: 12/31/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a progressive neurodegenerative disease that is the leading genetic cause of infantile death. It is caused by a severe deficiency of the ubiquitously expressed Survival Motor Neuron (SMN) protein. SMA is characterized by α-lower motor neuron loss and muscle atrophy, however, there is a growing list of tissues impacted by a SMN deficiency beyond motor neurons. The non-neuronal defects are observed in the most severe Type I SMA patients and most of the widely used SMA mouse models, however, as effective therapeutics are developed, it is unclear whether additional symptoms will be uncovered in longer lived patients. Recently, the immune system and inflammation has been identified as a contributor to neurodegenerative diseases such as ALS. To determine whether the immune system is comprised in SMA, we analyzed the spleen and immunological components in SMA mice. In this report, we identify: a significant reduction in spleen size in multiple SMA mouse models and a pathological reduction in red pulp and extramedullary hematopoiesis. Additionally, red pulp macrophages, a discrete subset of yolk sac-derived macrophages, were found to be altered in SMA spleens even in pre-symptomatic post-natal day 2 animals. These cells, which are involved in iron metabolism and the phagocytosis of erythrocytes and blood-borne pathogens are significantly reduced prior to the development of the neurodegenerative hallmarks of SMA, implying a differential role of SMN in myeloid cell ontogeny. Collectively, these results demonstrate that SMN deficiency impacts spleen development and suggests a potential role for immunological development in SMA.
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Affiliation(s)
- Marie-Therese Khairallah
- Molecular Pathogeneses and Therapeutics Program.,Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | - Jacob Astroski
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Sarah K Custer
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Elliot J Androphy
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA
| | | | - Christian L Lorson
- Molecular Pathogeneses and Therapeutics Program.,Bond Life Sciences Center, University of Missouri, Columbia, MO, USA.,Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA
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36
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Systemic peptide-mediated oligonucleotide therapy improves long-term survival in spinal muscular atrophy. Proc Natl Acad Sci U S A 2016; 113:10962-7. [PMID: 27621445 DOI: 10.1073/pnas.1605731113] [Citation(s) in RCA: 143] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The development of antisense oligonucleotide therapy is an important advance in the identification of corrective therapy for neuromuscular diseases, such as spinal muscular atrophy (SMA). Because of difficulties of delivering single-stranded oligonucleotides to the CNS, current approaches have been restricted to using invasive intrathecal single-stranded oligonucleotide delivery. Here, we report an advanced peptide-oligonucleotide, Pip6a-morpholino phosphorodiamidate oligomer (PMO), which demonstrates potent efficacy in both the CNS and peripheral tissues in severe SMA mice following systemic administration. SMA results from reduced levels of the ubiquitously expressed survival motor neuron (SMN) protein because of loss-of-function mutations in the SMN1 gene. Therapeutic splice-switching oligonucleotides (SSOs) modulate exon 7 splicing of the nearly identical SMN2 gene to generate functional SMN protein. Pip6a-PMO yields SMN expression at high efficiency in peripheral and CNS tissues, resulting in profound phenotypic correction at doses an order-of-magnitude lower than required by standard naked SSOs. Survival is dramatically extended from 12 d to a mean of 456 d, with improvement in neuromuscular junction morphology, down-regulation of transcripts related to programmed cell death in the spinal cord, and normalization of circulating insulin-like growth factor 1. The potent systemic efficacy of Pip6a-PMO, targeting both peripheral as well as CNS tissues, demonstrates the high clinical potential of peptide-PMO therapy for SMA.
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37
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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: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [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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38
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Burns JK, Kothary R, Parks RJ. Opening the window: The case for carrier and perinatal screening for spinal muscular atrophy. Neuromuscul Disord 2016; 26:551-9. [PMID: 27460292 DOI: 10.1016/j.nmd.2016.06.459] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 06/20/2016] [Accepted: 06/21/2016] [Indexed: 11/26/2022]
Abstract
Spinal muscular atrophy (SMA) is the most common genetically inherited neurodegenerative disease that leads to infant mortality worldwide. SMA is caused by genetic deletion or mutation in the survival of motor neuron 1 (SMN1) gene, which results in a deficiency in SMN protein. For reasons that are still unclear, SMN protein deficiency predominantly affects α-motor neurons, resulting in their degeneration and subsequent paralysis of limb and trunk muscles, progressing to death in severe cases. Emerging evidence suggests that SMN protein deficiency also affects the heart, autonomic nervous system, skeletal muscle, liver, pancreas and perhaps many other organs. Currently, there is no cure for SMA. Patient treatment includes respiratory care, physiotherapy, and nutritional management, which can somewhat ameliorate disease symptoms and increase life span. Fortunately, several novel therapies have advanced to human clinical trials. However, data from studies in animal models of SMA indicate that the greatest therapeutic benefit is achieved through initiating treatment as early as possible, before widespread loss of motor neurons has occurred. In this review, we discuss the merit of carrier and perinatal patient screening for SMA considering the efficacy of emerging therapeutics and the physical, emotional and financial burden of the disease on affected families and society.
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Affiliation(s)
- Joseph K Burns
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Canada; Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Canada; University of Ottawa Centre for Neuromuscular Disease, Ottawa, Canada
| | - Rashmi Kothary
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Canada; University of Ottawa Centre for Neuromuscular Disease, Ottawa, Canada; Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada; Department of Medicine, University of Ottawa, Ottawa, Canada
| | - Robin J Parks
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Canada; Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Canada; University of Ottawa Centre for Neuromuscular Disease, Ottawa, Canada; Department of Medicine, University of Ottawa, Ottawa, Canada.
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39
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Simone C, Ramirez A, Bucchia M, Rinchetti P, Rideout H, Papadimitriou D, Re DB, Corti S. Is spinal muscular atrophy a disease of the motor neurons only: pathogenesis and therapeutic implications? Cell Mol Life Sci 2016; 73:1003-20. [PMID: 26681261 PMCID: PMC4756905 DOI: 10.1007/s00018-015-2106-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 11/30/2015] [Accepted: 12/01/2015] [Indexed: 01/16/2023]
Abstract
Spinal muscular atrophy (SMA) is a genetic neurological disease that causes infant mortality; no effective therapies are currently available. SMA is due to homozygous mutations and/or deletions in the survival motor neuron 1 gene and subsequent reduction of the SMN protein, leading to the death of motor neurons. However, there is increasing evidence that in addition to motor neurons, other cell types are contributing to SMA pathology. In this review, we will discuss the involvement of non-motor neuronal cells, located both inside and outside the central nervous system, in disease onset and progression. Even if SMN restoration in motor neurons is needed, it has been shown that optimal phenotypic amelioration in animal models of SMA requires a more widespread SMN correction. It has been demonstrated that non-motor neuronal cells are also involved in disease pathogenesis and could have important therapeutic implications. For these reasons it will be crucial to take this evidence into account for the clinical translation of the novel therapeutic approaches.
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Affiliation(s)
- Chiara Simone
- Neuroscience Section, Neurology Unit, Department of Pathophysiology and Transplantation (DEPT), Dino Ferrari Centre, University of Milan, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy
| | - Agnese Ramirez
- Neuroscience Section, Neurology Unit, Department of Pathophysiology and Transplantation (DEPT), Dino Ferrari Centre, University of Milan, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy
| | - Monica Bucchia
- Neuroscience Section, Neurology Unit, Department of Pathophysiology and Transplantation (DEPT), Dino Ferrari Centre, University of Milan, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy
| | - Paola Rinchetti
- Neuroscience Section, Neurology Unit, Department of Pathophysiology and Transplantation (DEPT), Dino Ferrari Centre, University of Milan, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy
| | - Hardy Rideout
- Division of Basic Neurosciences, Biomedical Research Foundation of the Academy of Athens (BRFAA), Soranou Efesiou 4, 115 27, Athens, Greece
| | - Dimitra Papadimitriou
- Division of Basic Neurosciences, Biomedical Research Foundation of the Academy of Athens (BRFAA), Soranou Efesiou 4, 115 27, Athens, Greece
| | - Diane B Re
- Department of Environmental Health Sciences, Columbia University, New York, NY, 10032, USA
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, 10032, USA
| | - Stefania Corti
- Neuroscience Section, Neurology Unit, Department of Pathophysiology and Transplantation (DEPT), Dino Ferrari Centre, University of Milan, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy.
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40
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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] [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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41
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Davis RH, Miller EA, Zhang RZ, Swoboda KJ. Responses to Fasting and Glucose Loading in a Cohort of Well Children with Spinal Muscular Atrophy Type II. J Pediatr 2015; 167:1362-8.e1. [PMID: 26454573 PMCID: PMC7599085 DOI: 10.1016/j.jpeds.2015.09.023] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 07/27/2015] [Accepted: 09/03/2015] [Indexed: 12/30/2022]
Abstract
OBJECTIVE To examine the impact of fasting and glucose tolerance on selected metabolic variables in children with spinal muscular atrophy (SMA) type II in a well state, secondary to reports of glucose regulation abnormalities in SMA. STUDY DESIGN In this prospective pilot study, 6 children aged 7-11 years with SMA type II participated in an oral glucose tolerance test and a supervised medical fast during 2 overnight visits at the University of Utah. At baseline, a dual-energy x-ray absorptiometry scan was performed to determine body composition. Laboratory test results were obtained at baseline and in response to the respective interventions. Data analysis was descriptive. Prefasting and postfasting data were evaluated using the Wilcoxon signed-rank test. RESULTS Based on the dual-energy x-ray absorptiometry scan, all 6 children were variably obese at baseline. All 6 exhibited hyperinsulinemia, and 3 of 6 met formal American Diabetes Association criteria for impaired glucose tolerance. According to homeostatic insulin resistance calculations, 5 of the 6 participants were insulin-resistant. All 6 participants tolerated a monitored fast for 20 hours without hypoglycemia (blood glucose <54 mg/dL). Free fatty acid levels increased significantly from prefasting to postfasting, whereas levels of several plasma amino acids decreased significantly during fasting. CONCLUSION Children with SMA type II defined as obese using objective variables are at increased risk for impaired glucose tolerance regardless of whether or not they visually appear obese. Further studies are needed to determine the prevalence of impaired glucose tolerance and tolerance for fasting within the broader heterogeneous SMA population and to develop appropriate guidelines for intervention.
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Affiliation(s)
- Rebecca Hurst Davis
- Originally affiliated with University of Utah, Department of Neurology Pediatric Motor Disorders Research Program and Division of Nutrition; University of Utah, Division of Nutrition, 30 North 1900 East SOM 3R149, Salt Lake City, UT 84132, Phone: 801-585-1499, Fax: 801-587-9346, Currently affiliated with Intermountain Healthcare, Salt Lake City, UT
| | - Elizabeth A. Miller
- Originally affiliated with University of Utah, Department of Neurology Pediatric Motor Disorders Research Program, Salt Lake City, UT, Currently affiliated with Shriner’s Children’s Hospital, Salt Lake City, UT
| | - Ren Zhe Zhang
- Originally affiliated with University of Utah, Department of Neurology Pediatric Motor Disorders Research Program, Salt Lake City, UT., Currently affiliated with Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA
| | - Kathryn J. Swoboda
- Center for Human Genetics Research, Department of Neurology, Massachusetts General Hospital, 185 Cambridge, Simches 5-238, Boston, MA 02114
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Gombash SE, Cowley CJ, Fitzgerald JA, Iyer CC, Fried D, McGovern VL, Williams KC, Burghes AHM, Christofi FL, Gulbransen BD, Foust KD. SMN deficiency disrupts gastrointestinal and enteric nervous system function in mice. Hum Mol Genet 2015; 24:3847-60. [PMID: 25859009 DOI: 10.1093/hmg/ddv127] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 04/07/2015] [Indexed: 12/19/2022] Open
Abstract
The 2007 Consensus Statement for Standard of Care in Spinal Muscular Atrophy (SMA) notes that patients suffer from gastroesophageal reflux, constipation and delayed gastric emptying. We used two mouse models of SMA to determine whether functional GI complications are a direct consequence of or are secondary to survival motor neuron (Smn) deficiency. Our results show that despite normal activity levels and food and water intake, Smn deficiency caused constipation, delayed gastric emptying, slow intestinal transit and reduced colonic motility without gross anatomical or histopathological abnormalities. These changes indicate alterations to the intrinsic neural control of gut functions mediated by the enteric nervous system (ENS). Indeed, Smn deficiency led to disrupted ENS signaling to the smooth muscle of the colon but did not cause enteric neuron loss. High-frequency electrical field stimulation (EFS) of distal colon segments produced up to a 10-fold greater contractile response in Smn deficient tissues. EFS responses were not corrected by the addition of a neuronal nitric oxide synthase inhibitor indicating that the increased contractility was due to hyperexcitability and not disinhibition of the circuitry. The GI symptoms observed in mice are similar to those reported in SMA patients. Together these data suggest that ENS cells are susceptible to Smn deficiency and may underlie the patient GI symptoms.
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Affiliation(s)
| | | | | | - Chitra C Iyer
- Department of Molecular & Cellular Biochemistry, Wexner Medical Center and
| | - David Fried
- Department of Physiology, Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA and
| | - Vicki L McGovern
- Department of Molecular & Cellular Biochemistry, Wexner Medical Center and
| | - Kent C Williams
- Division of Pediatric Gastroenterology, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Arthur H M Burghes
- Department of Molecular & Cellular Biochemistry, Wexner Medical Center and
| | - Fedias L Christofi
- Department of Anesthesiology, The Ohio State University, Columbus, OH 43210, USA
| | - Brian D Gulbransen
- Department of Physiology, Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA and
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Arnold WD, Kassar D, Kissel JT. Spinal muscular atrophy: diagnosis and management in a new therapeutic era. Muscle Nerve 2014; 51:157-67. [PMID: 25346245 DOI: 10.1002/mus.24497] [Citation(s) in RCA: 203] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/20/2014] [Indexed: 12/13/2022]
Abstract
Spinal muscular atrophy (SMA) describes a group of disorders associated with spinal motor neuron loss. In this review we provide an update regarding the most common form of SMA, proximal or 5q-SMA, and discuss the contemporary approach to diagnosis and treatment. Electromyography and muscle biopsy features of denervation were once the basis for diagnosis, but molecular testing for homozygous deletion or mutation of the SMN1 gene allows efficient and specific diagnosis. In combination with loss of SMN1, patients retain variable numbers of copies of a second similar gene, SMN2, which produces reduced levels of the survival motor neuron (SMN) protein that are insufficient for normal motor neuron function. Despite the fact that understanding of how ubiquitous reduction of SMN protein leads to motor neuron loss remains incomplete, several promising therapeutics are now being tested in early-phase clinical trials.
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Affiliation(s)
- W David Arnold
- Division of Neuromuscular Disorders, Department of Neurology, Wexner Medical Center, The Ohio State University, 395 West 12th Avenue, Columbus, Ohio, 43210, USA; Department of Physical Medicine and Rehabilitation, Wexner Medical Center, The Ohio State University, Columbus, Ohio, USA
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Coque E, Raoul C, Bowerman M. ROCK inhibition as a therapy for spinal muscular atrophy: understanding the repercussions on multiple cellular targets. Front Neurosci 2014; 8:271. [PMID: 25221469 PMCID: PMC4148024 DOI: 10.3389/fnins.2014.00271] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 08/11/2014] [Indexed: 12/28/2022] Open
Abstract
Spinal muscular atrophy (SMA) is the most common genetic disease causing infant death, due to an extended loss of motoneurons. This neuromuscular disorder results from deletions and/or mutations within the Survival Motor Neuron 1 (SMN1) gene, leading to a pathological decreased expression of functional full-length SMN protein. Emerging studies suggest that the small GTPase RhoA and its major downstream effector Rho kinase (ROCK), which both play an instrumental role in cytoskeleton organization, contribute to the pathology of motoneuron diseases. Indeed, an enhanced activation of RhoA and ROCK has been reported in the spinal cord of an SMA mouse model. Moreover, the treatment of SMA mice with ROCK inhibitors leads to an increased lifespan as well as improved skeletal muscle and neuromuscular junction pathology, without preventing motoneuron degeneration. Although motoneurons are the primary target in SMA, an increasing number of reports show that other cell types inside and outside the central nervous system contribute to SMA pathogenesis. As administration of ROCK inhibitors to SMA mice was systemic, the improvement in survival and phenotype could therefore be attributed to specific effects on motoneurons and/or on other non-neuronal cell types. In the present review, we will present the various roles of the RhoA/ROCK pathway in several SMA cellular targets including neurons, myoblasts, glial cells, cardiomyocytes and pancreatic cells as well as discuss how ROCK inhibition may ameliorate their health and function. It is most likely a concerted influence of ROCK modulation on all these cell types that ultimately lead to the observed benefits of pharmacological ROCK inhibition in SMA mice.
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Affiliation(s)
- Emmanuelle Coque
- The Institute for Neurosciences of Montpellier, Saint Eloi Hospital, Institut National de la Santé et de la Recherche Médicale UMR1051 Montpellier, France ; Université de Montpellier 1 and 2 Montpellier, France
| | - Cédric Raoul
- The Institute for Neurosciences of Montpellier, Saint Eloi Hospital, Institut National de la Santé et de la Recherche Médicale UMR1051 Montpellier, France ; Université de Montpellier 1 and 2 Montpellier, France
| | - Mélissa Bowerman
- The Institute for Neurosciences of Montpellier, Saint Eloi Hospital, Institut National de la Santé et de la Recherche Médicale UMR1051 Montpellier, France ; Université de Montpellier 1 and 2 Montpellier, France
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