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Signoria I, van der Pol WL, Groen EJN. Innovating spinal muscular atrophy models in the therapeutic era. Dis Model Mech 2023; 16:dmm050352. [PMID: 37787662 PMCID: PMC10565113 DOI: 10.1242/dmm.050352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a severe, monogenetic, neuromuscular disease. A thorough understanding of its genetic cause and the availability of robust models has led to the development and approval of three gene-targeting therapies. This is a unique and exciting development for the field of neuromuscular diseases, many of which remain untreatable. The development of therapies for SMA not only opens the door to future therapeutic possibilities for other genetic neuromuscular diseases, but also informs us about the limitations of such treatments. For example, treatment response varies widely and, for many patients, significant disability remains. Currently available SMA models best recapitulate the severe types of SMA, and these models are genetically and phenotypically more homogeneous than patients. Furthermore, treating patients is leading to a shift in phenotypes with increased variability in SMA clinical presentation. Therefore, there is a need to generate model systems that better reflect these developments. Here, we will first discuss current animal models of SMA and their limitations. Next, we will discuss the characteristics required to future-proof models to assist the field in the development of additional, novel therapies for SMA.
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Affiliation(s)
- Ilaria Signoria
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - W. Ludo van der Pol
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Ewout J. N. Groen
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
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2
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Sansa A, Miralles MP, Beltran M, Celma-Nos F, Calderó J, Garcera A, Soler RM. ERK MAPK signaling pathway inhibition as a potential target to prevent autophagy alterations in Spinal Muscular Atrophy motoneurons. Cell Death Discov 2023; 9:113. [PMID: 37019880 PMCID: PMC10076363 DOI: 10.1038/s41420-023-01409-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 03/21/2023] [Accepted: 03/22/2023] [Indexed: 04/07/2023] Open
Abstract
Spinal Muscular Atrophy (SMA) is a severe genetic neuromuscular disorder that occurs in childhood and is caused by misexpression of the survival motor neuron (SMN) protein. SMN reduction induces spinal cord motoneuron (MN) degeneration, which leads to progressive muscular atrophy and weakness. The link between SMN deficiency and the molecular mechanisms altered in SMA cells remains unclear. Autophagy, deregulation of intracellular survival pathways and ERK hyperphosphorylation may contribute to SMN-reduced MNs collapse, offering a useful strategy to develop new therapies to prevent neurodegeneration in SMA. Using SMA MN in vitro models, the effect of pharmacological inhibition of PI3K/Akt and ERK MAPK pathways on SMN and autophagy markers modulation was studied by western blot analysis and RT-qPCR. Experiments involved primary cultures of mouse SMA spinal cord MNs and differentiated SMA human MNs derived from induced pluripotent stem cells (iPSCs). Inhibition of the PI3K/Akt and the ERK MAPK pathways reduced SMN protein and mRNA levels. Importantly, mTOR phosphorylation, p62, and LC3-II autophagy markers protein level were decreased after ERK MAPK pharmacological inhibition. Furthermore, the intracellular calcium chelator BAPTA prevented ERK hyperphosphorylation in SMA cells. Our results propose a link between intracellular calcium, signaling pathways, and autophagy in SMA MNs, suggesting that ERK hyperphosphorylation may contribute to autophagy deregulation in SMN-reduced MNs.
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Affiliation(s)
- Alba Sansa
- Neuronal Signaling Unit, Experimental Medicine Department, Universitat de Lleida-IRBLleida, Rovira Roure, 80, 25198, Lleida, Spain
| | - Maria P Miralles
- Neuronal Signaling Unit, Experimental Medicine Department, Universitat de Lleida-IRBLleida, Rovira Roure, 80, 25198, Lleida, Spain
| | - Maria Beltran
- Neuronal Signaling Unit, Experimental Medicine Department, Universitat de Lleida-IRBLleida, Rovira Roure, 80, 25198, Lleida, Spain
| | - Ferran Celma-Nos
- Neuronal Signaling Unit, Experimental Medicine Department, Universitat de Lleida-IRBLleida, Rovira Roure, 80, 25198, Lleida, Spain
| | - Jordi Calderó
- Patologia Neuromuscular Experimental, Experimental Medicine Department, Universitat de Lleida-IRBLleida, Rovira Roure, 80, 25198, Lleida, Spain
| | - Ana Garcera
- Neuronal Signaling Unit, Experimental Medicine Department, Universitat de Lleida-IRBLleida, Rovira Roure, 80, 25198, Lleida, Spain
| | - Rosa M Soler
- Neuronal Signaling Unit, Experimental Medicine Department, Universitat de Lleida-IRBLleida, Rovira Roure, 80, 25198, Lleida, Spain.
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3
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Faravelli I, Riboldi GM, Rinchetti P, Lotti F. The SMN Complex at the Crossroad between RNA Metabolism and Neurodegeneration. Int J Mol Sci 2023; 24:2247. [PMID: 36768569 PMCID: PMC9917330 DOI: 10.3390/ijms24032247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 01/17/2023] [Accepted: 01/20/2023] [Indexed: 01/24/2023] Open
Abstract
In the cell, RNA exists and functions in a complex with RNA binding proteins (RBPs) that regulate each step of the RNA life cycle from transcription to degradation. Central to this regulation is the role of several molecular chaperones that ensure the correct interactions between RNA and proteins, while aiding the biogenesis of large RNA-protein complexes (ribonucleoproteins or RNPs). Accurate formation of RNPs is fundamentally important to cellular development and function, and its impairment often leads to disease. The survival motor neuron (SMN) protein exemplifies this biological paradigm. SMN is part of a multi-protein complex essential for the biogenesis of various RNPs that function in RNA metabolism. Mutations leading to SMN deficiency cause the neurodegenerative disease spinal muscular atrophy (SMA). A fundamental question in SMA biology is how selective motor system dysfunction results from reduced levels of the ubiquitously expressed SMN protein. Recent clarification of the central role of the SMN complex in RNA metabolism and a thorough characterization of animal models of SMA have significantly advanced our knowledge of the molecular basis of the disease. Here we review the expanding role of SMN in the regulation of gene expression through its multiple functions in RNP biogenesis. We discuss developments in our understanding of SMN activity as a molecular chaperone of RNPs and how disruption of SMN-dependent RNA pathways can contribute to the SMA phenotype.
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Affiliation(s)
- Irene Faravelli
- Department of Stem Cell & Regenerative Biology, Harvard University, Cambridge, MA 02138, USA
- Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology, and Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Giulietta M. Riboldi
- Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology, and Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
- The Marlene and Paolo Fresco Institute for Parkinson’s and Movement Disorders, NYU Langone Health, New York, NY 10017, USA
| | - Paola Rinchetti
- Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology, and Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Francesco Lotti
- Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology, and Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
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4
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Miralles MP, Sansa A, Beltran M, Soler RM, Garcera A. Survival motor neuron protein and neurite degeneration are regulated by Gemin3 in spinal muscular atrophy motoneurons. Front Cell Neurosci 2022; 16:1054270. [PMID: 36619669 PMCID: PMC9813745 DOI: 10.3389/fncel.2022.1054270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 12/06/2022] [Indexed: 12/24/2022] Open
Abstract
Spinal Muscular Atrophy (SMA) is a genetic neuromuscular disorder caused by reduction of the ubiquitously expressed protein Survival Motor Neuron (SMN). Low levels of SMN impact on spinal cord motoneurons (MNs) causing their degeneration and progressive muscle weakness and atrophy. To study the molecular mechanisms leading to cell loss in SMN-reduced MNs, we analyzed the NF-κB intracellular pathway in SMA models. NF-κB pathway activation is required for survival and regulates SMN levels in cultured MNs. Here we describe that NF-κB members, inhibitor of kappa B kinase beta (IKKβ), and RelA, were reduced in SMA mouse and human MNs. In addition, we observed that Gemin3 protein level was decreased in SMA MNs, but not in non-neuronal SMA cells. Gemin3 is a core member of the SMN complex responsible for small nuclear ribonucleoprotein biogenesis, and it regulates NF-κB activation through the mitogen-activated protein kinase TAK1. Our experiments showed that Gemin3 knockdown reduced SMN, IKKβ, and RelA protein levels, and caused significant neurite degeneration. Overexpression of SMN increased Gemin3 protein in SMA MNs, but did not prevent neurite degeneration in Gemin3 knockdown cells. These data indicated that Gemin3 reduction may contribute to cell degeneration in SMA MNs.
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5
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Adami R, Bottai D. NSC Physiological Features in Spinal Muscular Atrophy: SMN Deficiency Effects on Neurogenesis. Int J Mol Sci 2022; 23:ijms232315209. [PMID: 36499528 PMCID: PMC9736802 DOI: 10.3390/ijms232315209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 11/20/2022] [Accepted: 11/30/2022] [Indexed: 12/08/2022] Open
Abstract
While the U.S. Food and Drug Administration and the European Medicines Evaluation Agency have recently approved new drugs to treat spinal muscular atrophy 1 (SMA1) in young patients, they are mostly ineffective in older patients since many motor neurons have already been lost. Therefore, understanding nervous system (NS) physiology in SMA patients is essential. Consequently, studying neural stem cells (NSCs) from SMA patients is of significant interest in searching for new treatment targets that will enable researchers to identify new pharmacological approaches. However, studying NSCs in these patients is challenging since their isolation damages the NS, making it impossible with living patients. Nevertheless, it is possible to study NSCs from animal models or create them by differentiating induced pluripotent stem cells obtained from SMA patient peripheral tissues. On the other hand, therapeutic interventions such as NSCs transplantation could ameliorate SMA condition. This review summarizes current knowledge on the physiological properties of NSCs from animals and human cellular models with an SMA background converging on the molecular and neuronal circuit formation alterations of SMA fetuses and is not focused on the treatment of SMA. By understanding how SMA alters NSC physiology, we can identify new and promising interventions that could help support affected patients.
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Grice SJ, Liu JL. Motor defects in a Drosophila model for spinal muscular atrophy result from SMN depletion during early neurogenesis. PLoS Genet 2022; 18:e1010325. [PMID: 35877682 PMCID: PMC9352204 DOI: 10.1371/journal.pgen.1010325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 08/04/2022] [Accepted: 07/05/2022] [Indexed: 11/18/2022] Open
Abstract
Spinal muscular atrophy (SMA) is the most common autosomal recessive neurodegenerative disease, and is characterised by spinal motor neuron loss, impaired motor function and, often, premature death. Mutations and deletions in the widely expressed survival motor neuron 1 (SMN1) gene cause SMA; however, the mechanisms underlying the selectivity of motor neuron degeneration are not well understood. Although SMA is degenerative in nature, SMN function during embryonic and early postnatal development appears to be essential for motor neuron survival in animal models and humans. Notwithstanding, how developmental defects contribute to the subversion of postnatal and adult motor function remains elusive. Here, in a Drosophila SMA model, we show that neurodevelopmental defects precede gross locomotor dysfunction in larvae. Furthermore, to specifically address the relevance of SMN during neurogenesis and in neurogenic cell types, we show that SMN knockdown using neuroblast-specific and pan-neuronal drivers, but not differentiated neuron or glial cell drivers, impairs adult motor function. Using targeted knockdown, we further restricted SMN manipulation in neuroblasts to a defined time window. Our aim was to express specifically in the neuronal progenitor cell types that have not formed synapses, and thus a time that precedes neuromuscular junction formation and maturation. By restoring SMN levels in these distinct neuronal population, we partially rescue the larval locomotor defects of Smn mutants. Finally, combinatorial SMN knockdown in immature and mature neurons synergistically enhances the locomotor and survival phenotypes. Our in-vivo study is the first to directly rescue the motor defects of an SMA model by expressing Smn in an identifiable population of Drosophila neuroblasts and developing neurons, highlighting that neuronal sensitivity to SMN loss may arise before synapse establishment and nerve cell maturation. Spinal muscular atrophy (SMA) is the most common genetic cause of infant mortality and leads to the degeneration of the nerves that control muscle function. Loss-of-function mutations in the widely expressed survival motor neuron 1 (SMN1) gene cause SMA, but how low levels of SMN protein cause the neuronal dysfunction is not known. Although SMA is a disease of nerve degeneration, SMN function during nerve cell development may be important, particularly in severe forms of SMA. Nevertheless, how the defects during development and throughout early life contribute to the disease is not well understood. We have previously demonstrated that SMN protein becomes enriched in neuroblasts, which are the cells that divide to produce neurons. In the present study, motor defects observed in our fly model for SMA could be rescued by restoring SMN in neuroblasts alone. In addition, we show that knocking down SMN in healthy flies within the same cell type causes impaired motor function. The present study shows that the manipulation of SMN in a developmentally important cell type can cause motor defects, indicating that a period of abnormal neurodevelopment may contribute to SMA.
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Affiliation(s)
- Stuart J. Grice
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
- * E-mail: (SJG); , (J-LL)
| | - Ji-Long Liu
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
- School of Life Science and Technology, Shanghai, Tech University, Shanghai, China
- * E-mail: (SJG); , (J-LL)
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7
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Chang WF, Lin TY, Peng M, Chang CC, Xu J, Hsieh-Li HM, Liu JL, Sung LY. SMN Enhances Pluripotent Genes Expression and Facilitates Cell Reprogramming. Stem Cells Dev 2022; 31:696-705. [PMID: 35848514 DOI: 10.1089/scd.2022.0091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Survival motor neuron (SMN) plays important roles in snRNPs assembly and mRNA splicing. Deficiency of SMN causes spinal muscular atrophy (SMA), a leading genetic disease of childhood mortality. Previous studies have shown that SMN regulates stem cell self-renewal and pluripotency in Drosophila and in mouse, and is abundantly expressed in mouse embryonic stem cells (ESCs). However, whether SMN is required for the establishment of pluripotency is unclear. Herein, we show that SMN is gradually upregulated in pre-implantation mouse embryos and cultured cells undergoing cell reprogramming. Ectopic expression of SMN increased the cell reprogramming efficiency, whereas knockdown of SMN impeded iPSC colony formation. iPSCs could be derived from SMA model mice, but certain impairment in differentiation capacity may present. The ectopic overexpression of SMN in iPSCs can upregulate the expression levels of some pluripotent genes and restore the neuronal differentiation capacity of SMA-iPSCs. Taken together, our findings not only demonstrate the functional relevance of SMN and the establishment of cell pluripotency, but also propose its potential application in facilitating iPSC derivation.
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Affiliation(s)
- Wei-Fang Chang
- National Taiwan University, 33561, Institute of Biotechnology, Taipei, Taiwan;
| | - Tzu-Ying Lin
- National Taiwan University, 33561, Institute of Biotechnology, Taipei, Taiwan;
| | - Min Peng
- National Taiwan University, 33561, Institute of Biotechnology, Taipei, Taiwan;
| | - Chia-Chun Chang
- National Taiwan University, 33561, Institute of Biotechnology, Taipei, Taiwan;
| | - Jie Xu
- University of Michigan Medical Center, 166144, Ann Arbor, Michigan, United States;
| | - Hsiu Mei Hsieh-Li
- National Taiwan Normal University, 34879, Department of Life Science, Taipei, Taiwan;
| | - Ji-Long Liu
- ShanghaiTech University, 387433, Shanghai, China;
| | - Li-Ying Sung
- National Taiwan University, 33561, Institute of Biotechnology, Taipei, Taiwan, 10617;
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8
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Muinos-Bühl A, Rombo R, Janzen E, Ling KK, Hupperich K, Rigo F, Bennett CF, Wirth B. Combinatorial ASO-mediated therapy with low dose SMN and the protective modifier Chp1 is not sufficient to ameliorate SMA pathology hallmarks. Neurobiol Dis 2022; 171:105795. [PMID: 35724821 DOI: 10.1016/j.nbd.2022.105795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 05/17/2022] [Accepted: 06/14/2022] [Indexed: 10/18/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a devastating genetically inherited neuromuscular disorder characterized by the progressive loss of motor neurons in the spinal cord, leading to muscle atrophy and weakness. Although SMA is caused by homozygous mutations in SMN1, the disease severity is mainly determined by the copy number of SMN2, an almost identical gene that produces ~10% correctly spliced SMN transcripts. Recently, three FDA- and EMA-approved therapies that either increase correctly spliced SMN2 transcripts (nusinersen and risdiplam) or replace SMN1 (onasemnogen abeparvovec-xioi) have revolutionized the clinical outcome in SMA patients. However, for severely affected SMA individuals carrying only two SMN2 copies even a presymptomatic therapy might be insufficient to fully counteract disease development. Therefore, SMN-independent compounds supporting SMN-dependent therapies represent a promising therapeutic approach. Recently, we have shown a significant amelioration of SMA disease hallmarks in a severely affected SMA mouse carrying a mutant Chp1 allele when combined with low-dose of SMN antisense oligonucleotide (ASO) treatment. CHP1 is a direct interacting partner of PLS3, a strong protective modifier of SMA. Both proteins ameliorate impaired endocytosis in SMA and significantly restore pathological hallmarks in mice. Here, we aimed to pharmacologically reduce CHP1 levels in an ASO-based combinatorial therapy targeting SMN and Chp1. Chp1 modulation is a major challenge since its genetic reduction to ~50% has shown to ameliorate SMA pathology, while the downregulation below that level causes cerebellar ataxia. Efficacy and tolerability studies determined that a single injection of 30 μg Chp1-ASO4 in the CNS is a safe dosage that significantly reduced CHP1 levels to ~50% at postnatal day (PND)14. Unfortunately, neither electrophysiological predictors such as compound muscle action potential (CMAP) or motor unit number estimation (MUNE) nor histological hallmarks of SMA in neuromuscular junction (NMJ), spinal cord or muscle were ameliorated in SMA mice treated with Chp1-ASO4 compared to CTRL-ASO at PND21. Surprisingly, CHP1 levels were almost at control level 4-weeks post injection, indicating a rather short-term effect of the ASO. Therefore, we re-administrated Chp1-ASO4 by i.c.v. bolus injection at PND28. However, no significant improvement of SMA hallmarks were seen at 2 month-of-age either. In conclusion, in contrast to the protective effect of genetically-induced Chp1 reduction on SMA, combinatorial therapy with Chp1- and SMN-ASOs failed to significantly ameliorate the SMA pathology. Chp1-ASOs compared to SMN-ASO proved to have rather short-term effect and even reinjection had no significant impact on SMA progression, suggesting that further optimization of the ASO may be required to fully explore the combination.
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Affiliation(s)
- A Muinos-Bühl
- Institute of Human Genetics, 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.
| | - R Rombo
- Institute of Human Genetics, 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.
| | - E Janzen
- Institute of Human Genetics, 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
| | - K K Ling
- Ionis Pharmaceuticals, Carlsbad, CA 92008, USA.
| | - K Hupperich
- Institute of Human Genetics, 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
| | - F Rigo
- Ionis Pharmaceuticals, Carlsbad, CA 92008, USA.
| | - C F Bennett
- Ionis Pharmaceuticals, Carlsbad, CA 92008, USA.
| | - B Wirth
- Institute of Human Genetics, 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, 50931 Cologne, Germany.
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9
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Allison RL, Welby E, Khayrullina G, Burnett BG, Ebert AD. Viral mediated knockdown of GATA6 in SMA iPSC-derived astrocytes prevents motor neuron loss and microglial activation. Glia 2022; 70:989-1004. [PMID: 35088910 PMCID: PMC9303278 DOI: 10.1002/glia.24153] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Revised: 01/18/2022] [Accepted: 01/18/2022] [Indexed: 12/22/2022]
Abstract
Spinal muscular atrophy (SMA), a pediatric genetic disorder, is characterized by the profound loss of spinal cord motor neurons and subsequent muscle atrophy and death. Although the mechanisms underlying motor neuron loss are not entirely clear, data from our work and others support the idea that glial cells contribute to disease pathology. GATA6, a transcription factor that we have previously shown to be upregulated in SMA astrocytes, is negatively regulated by SMN (survival motor neuron) and can increase the expression of inflammatory regulator NFκB. In this study, we identified upregulated GATA6 as a contributor to increased activation, pro-inflammatory ligand production, and neurotoxicity in spinal-cord patterned astrocytes differentiated from SMA patient induced pluripotent stem cells. Reducing GATA6 expression in SMA astrocytes via lentiviral infection ameliorated these effects to healthy control levels. Additionally, we found that SMA astrocytes contribute to SMA microglial phagocytosis, which was again decreased by lentiviral-mediated knockdown of GATA6. Together these data identify a role of GATA6 in SMA astrocyte pathology and further highlight glia as important targets of therapeutic intervention in SMA.
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Affiliation(s)
- Reilly L Allison
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Emily Welby
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Guzal Khayrullina
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University, Bethesda, Maryland, USA
| | - Barrington G Burnett
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University, Bethesda, Maryland, USA
| | - Allison D Ebert
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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10
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Varderidou-Minasian S, Verheijen BM, Harschnitz O, Kling S, Karst H, van der Pol WL, Pasterkamp RJ, Altelaar M. Spinal Muscular Atrophy Patient iPSC-Derived Motor Neurons Display Altered Proteomes at Early Stages of Differentiation. ACS OMEGA 2021; 6:35375-35388. [PMID: 34984269 PMCID: PMC8717385 DOI: 10.1021/acsomega.1c04688] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 11/24/2021] [Indexed: 05/08/2023]
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disorder characterized by loss of motor neurons (MN) in the spinal cord leading to progressive muscle atrophy and weakness. SMA is caused by mutations in the survival motor neuron 1 (SMN1) gene, resulting in reduced levels of survival motor neuron (SMN) protein. The mechanisms that link SMN deficiency to selective motor neuron dysfunction in SMA remain largely unknown. We present here, for the first time, a comprehensive quantitative TMT-10plex proteomics analysis that covers the development of induced pluripotent stem cell-derived MNs from both healthy individuals and SMA patients. We show that the proteomes of SMA samples segregate from controls already at early stages of neuronal differentiation. The altered proteomic signature in SMA MNs is associated with mRNA splicing, ribonucleoprotein biogenesis, organelle organization, cellular biogenesis, and metabolic processes. We highlight several known SMN-binding partners and evaluate their expression changes during MN differentiation. In addition, we compared our study to human and mouse in vivo proteomic studies revealing distinct and similar signatures. Altogether, our work provides a comprehensive resource of molecular events during early stages of MN differentiation, containing potentially therapeutically interesting protein expression profiles for SMA.
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Affiliation(s)
- Suzy Varderidou-Minasian
- Biomolecular
Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular
Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Padualaan 8, 3584
CH Utrecht, The Netherlands
- Netherlands
Proteomics Center, Padualaan
8, 3584 CH Utrecht, The Netherlands
| | - Bert M. Verheijen
- Department
of Translational Neuroscience, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CG Utrecht, The Netherlands
- Department
of Neurology and Neurosurgery, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Oliver Harschnitz
- Department
of Translational Neuroscience, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CG Utrecht, The Netherlands
- Department
of Neurology and Neurosurgery, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Sandra Kling
- Department
of Translational Neuroscience, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CG Utrecht, The Netherlands
- Department
of Neurology and Neurosurgery, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Henk Karst
- Department
of Translational Neuroscience, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CG Utrecht, The Netherlands
| | - W. Ludo van der Pol
- Department
of Neurology and Neurosurgery, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - R. Jeroen Pasterkamp
- Department
of Translational Neuroscience, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CG Utrecht, The Netherlands
| | - Maarten Altelaar
- Biomolecular
Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular
Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Padualaan 8, 3584
CH Utrecht, The Netherlands
- Netherlands
Proteomics Center, Padualaan
8, 3584 CH Utrecht, The Netherlands
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11
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Genetic architecture of motor neuron diseases. J Neurol Sci 2021; 434:120099. [PMID: 34965490 DOI: 10.1016/j.jns.2021.120099] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 11/26/2021] [Accepted: 12/14/2021] [Indexed: 12/18/2022]
Abstract
Motor neuron diseases (MNDs) are rare and frequently fatal neurological disorders in which motor neurons within the brainstem and spinal cord regions slowly die. MNDs are primarily caused by genetic mutations, and > 100 different mutant genes in humans have been discovered thus far. Given the fact that many more MND-related genes have yet to be discovered, the growing body of genetic evidence has offered new insights into the diverse cellular and molecular mechanisms involved in the aetiology and pathogenesis of MNDs. This search may aid in the selection of potential candidate genes for future investigation and, eventually, may open the door to novel interventions to slow down disease progression. In this review paper, we have summarized detailed existing research findings of different MNDs, such as amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA), spinal bulbar muscle atrophy (SBMA) and hereditary spastic paraplegia (HSP) in relation to their complex genetic architecture.
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12
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Hensel N, Brickwedde H, Tsaknakis K, Grages A, Braunschweig L, Lüders KA, Lorenz HM, Lippross S, Walter LM, Tavassol F, Lienenklaus S, Neunaber C, Claus P, Hell AK. Altered bone development with impaired cartilage formation precedes neuromuscular symptoms in spinal muscular atrophy. Hum Mol Genet 2021; 29:2662-2673. [PMID: 32644125 DOI: 10.1093/hmg/ddaa145] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 07/06/2020] [Accepted: 07/06/2020] [Indexed: 01/04/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a fatal neurodegenerative disease of newborns and children caused by mutations or deletions of the survival of motoneuron gene 1 resulting in low levels of the SMN protein. While neuromuscular degeneration is the cardinal symptom of the disease, the reduction of the ubiquitously expressed SMN additionally elicits non-motoneuron symptoms. Impaired bone development is a key feature of SMA, but it is yet unknown whether this is an indirect functional consequence of muscle weakness or caused by bone-intrinsic mechanisms. Therefore, we radiologically examined SMA patients in a prospective, non-randomized cohort study characterizing bone size and bone mineral density (BMD) and performed equivalent measurements in pre-symptomatic SMA mice. BMD as well as lumbar vertebral body size were significantly reduced in SMA patients. This growth defect but not BMD reduction was confirmed in SMA mice by μCT before the onset of neuromuscular symptoms indicating that it is at least partially independent of neuromuscular degeneration. Interestingly, the number of chondroblasts in the hypertrophic zone of the growth plate was significantly reduced. This was underlined by RNAseq and expression data from developing SMA mice vertebral bodies, which revealed molecular changes related to cell division and cartilage remodeling. Together, these findings suggest a bone intrinsic defect in SMA. This phenotype may not be rescued by novel drugs that enhance SMN levels in the central nervous system only.
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Affiliation(s)
- Niko Hensel
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany.,Center for Systems Neurosciences (ZSN), Hannover, Germany
| | - Hermann Brickwedde
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany
| | - Konstantinos Tsaknakis
- Pediatric Orthopedics, Department of Trauma, Orthopedic and Plastic Surgery, University Medical Center Goettingen, Goettingen, Germany
| | - Antonia Grages
- Pediatric Orthopedics, Department of Trauma, Orthopedic and Plastic Surgery, University Medical Center Goettingen, Goettingen, Germany
| | - Lena Braunschweig
- Pediatric Orthopedics, Department of Trauma, Orthopedic and Plastic Surgery, University Medical Center Goettingen, Goettingen, Germany
| | - Katja A Lüders
- Pediatric Orthopedics, Department of Trauma, Orthopedic and Plastic Surgery, University Medical Center Goettingen, Goettingen, Germany
| | - Heiko M Lorenz
- Pediatric Orthopedics, Department of Trauma, Orthopedic and Plastic Surgery, University Medical Center Goettingen, Goettingen, Germany
| | - Sebastian Lippross
- Pediatric Orthopedics, Department of Trauma, Orthopedic and Plastic Surgery, University Medical Center Goettingen, Goettingen, Germany
| | - Lisa M Walter
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany.,Center for Systems Neurosciences (ZSN), Hannover, Germany
| | - Frank Tavassol
- Department of Oral and Maxillofacial Surgery, Hannover Medical School, Hannover, Germany
| | - Stefan Lienenklaus
- Institute for Laboratory Animal Science and Central Animal Facility, Hannover Medical School, Hannover, Germany
| | | | - Peter Claus
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany.,Center for Systems Neurosciences (ZSN), Hannover, Germany
| | - Anna K Hell
- Pediatric Orthopedics, Department of Trauma, Orthopedic and Plastic Surgery, University Medical Center Goettingen, Goettingen, Germany
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13
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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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14
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Villarroel-Campos D, Schiavo G, Sleigh JN. Dissection, in vivo imaging and analysis of the mouse epitrochleoanconeus muscle. J Anat 2021; 241:1108-1119. [PMID: 34121181 PMCID: PMC9558155 DOI: 10.1111/joa.13478] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 05/07/2021] [Accepted: 05/18/2021] [Indexed: 12/25/2022] Open
Abstract
Analysis of rodent muscles affords an opportunity to glean key insights into neuromuscular development and the detrimental impact of disease‐causing genetic mutations. Muscles of the distal leg, for instance the gastrocnemius and tibialis anterior, are commonly used in such studies with mice and rats. However, thin and flat muscles, which can be dissected, processed and imaged without major disruption to muscle fibres and nerve‐muscle contacts, are more suitable for accurate and detailed analyses of the peripheral motor nervous system. One such wholemount muscle is the predominantly fast twitch epitrochleoanconeus (ETA), which is located in the upper forelimb, innervated by the radial nerve, and contains relatively large and uniformly flat neuromuscular junctions (NMJs). To facilitate incorporation of the ETA into the experimental toolkit of the neuromuscular disease field, here, we describe a simple method for its rapid isolation (<5 min), supported by high‐resolution videos and step‐by‐step images. Furthermore, we outline how the ETA can be imaged in live, anaesthetised mice, to enable examination of dynamic cellular processes occurring at the NMJ and within intramuscular axons, including transport of organelles, such as mitochondria and signalling endosomes. Finally, we present reference data on wild‐type ETA fibre‐type composition in young adult, male C57BL6/J mice. Comparative neuroanatomical studies of different muscles in rodent models of disease can generate critical insights into pathogenesis and pathology; dissection of the wholemount ETA provides the possibility to diversify the repertoire of muscles analysed for this endeavour.
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Affiliation(s)
- David Villarroel-Campos
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Giampietro Schiavo
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK.,UK Dementia Research Institute, University College London, London, UK
| | - James N Sleigh
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK.,UK Dementia Research Institute, University College London, London, UK
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15
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Fulceri F, Biagioni F, Limanaqi F, Busceti CL, Ryskalin L, Lenzi P, Fornai F. Ultrastructural characterization of peripheral denervation in a mouse model of Type III spinal muscular atrophy. J Neural Transm (Vienna) 2021; 128:771-791. [PMID: 33999256 PMCID: PMC8205903 DOI: 10.1007/s00702-021-02353-9] [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: 02/11/2021] [Accepted: 05/10/2021] [Indexed: 01/02/2023]
Abstract
Spinal muscular atrophy (SMA) is a heritable, autosomal recessive neuromuscular disorder characterized by a loss of the survival of motor neurons (SMN) protein, which leads to degeneration of lower motor neurons, and muscle atrophy. Despite SMA being nosographically classified as a motor neuron disease, recent advances indicate that peripheral alterations at the level of the neuromuscular junction (NMJ), involving the muscle, and axons of the sensory-motor system, occur early, and may even precede motor neuron loss. In the present study, we used a mouse model of slow progressive (type III) SMA, whereby the absence of the mouse SMN protein is compensated by the expression of two human genes (heterozygous SMN1A2G, and SMN2). This leads to late disease onset and prolonged survival, which allows for dissecting slow degenerative steps operating early in SMA pathogenesis. In this purely morphological study carried out at transmission electron microscopy, we extend the examination of motor neurons and proximal axons towards peripheral components, including distal axons, muscle fibers, and also muscle spindles. We document remarkable ultrastructural alterations being consistent with early peripheral denervation in SMA, which may shift the ultimate anatomical target in neuromuscular disease from the spinal cord towards the muscle. This concerns mostly mitochondrial alterations within distal axons and muscle, which are quantified here through ultrastructural morphometry. The present study is expected to provide a deeper knowledge of early pathogenic mechanisms in SMA.
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Affiliation(s)
- Federica Fulceri
- Department of Clinical and Experimental Medicine, University of Pisa, Via Roma 55, 56126, Pisa, Italy
| | | | - Fiona Limanaqi
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 55, 56126, Pisa, Italy
| | - Carla L Busceti
- I.R.C.C.S. Neuromed, Via Atinense 18, 86077, Pozzilli, IS, Italy
| | - Larisa Ryskalin
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 55, 56126, Pisa, Italy
| | - Paola Lenzi
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 55, 56126, Pisa, Italy
| | - Francesco Fornai
- I.R.C.C.S. Neuromed, Via Atinense 18, 86077, Pozzilli, IS, Italy. .,Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 55, 56126, Pisa, Italy.
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16
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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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17
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Rietz A, Hodgetts KJ, Lusic H, Quist KM, Osman EY, Lorson CL, Androphy EJ. Short-duration splice promoting compound enables a tunable mouse model of spinal muscular atrophy. Life Sci Alliance 2020; 4:4/1/e202000889. [PMID: 33234679 PMCID: PMC7723287 DOI: 10.26508/lsa.202000889] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 11/06/2020] [Accepted: 11/09/2020] [Indexed: 11/24/2022] Open
Abstract
We describe drug treatment paradigms that allow investigation of cellular and molecular pathogenesis at different stages of spinal muscular atrophy in a mouse model. Spinal muscular atrophy (SMA) is a motor neuron disease and the leading genetic cause of infant mortality. SMA results from insufficient survival motor neuron (SMN) protein due to alternative splicing. Antisense oligonucleotides, gene therapy and splicing modifiers recently received FDA approval. Although severe SMA transgenic mouse models have been beneficial for testing therapeutic efficacy, models mimicking milder cases that manifest post-infancy have proven challenging to develop. We established a titratable model of mild and moderate SMA using the splicing compound NVS-SM2. Administration for 30 d prevented development of the SMA phenotype in severe SMA mice, which typically show rapid weakness and succumb by postnatal day 11. Furthermore, administration at day eight resulted in phenotypic recovery. Remarkably, acute dosing limited to the first 3 d of life significantly enhanced survival in two severe SMA mice models, easing the burden on neonates and demonstrating the compound as suitable for evaluation of follow-on therapies without potential drug–drug interactions. This pharmacologically tunable SMA model represents a useful tool to investigate cellular and molecular pathogenesis at different stages of disease.
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Affiliation(s)
- Anne Rietz
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Kevin J Hodgetts
- Laboratory for Drug Discovery in Neurodegeneration, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA, USA
| | - Hrvoje Lusic
- Laboratory for Drug Discovery in Neurodegeneration, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA, USA
| | - Kevin M Quist
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Erkan Y Osman
- Department of Veterinary Pathobiology, Bond Life Sciences Center, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA
| | - Christian L Lorson
- Department of Veterinary Pathobiology, Bond Life Sciences Center, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA
| | - Elliot J Androphy
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA
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18
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Kim JK, Jha NN, Feng Z, Faleiro MR, Chiriboga CA, Wei-Lapierre L, Dirksen RT, Ko CP, Monani UR. Muscle-specific SMN reduction reveals motor neuron-independent disease in spinal muscular atrophy models. J Clin Invest 2020; 130:1271-1287. [PMID: 32039917 DOI: 10.1172/jci131989] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 11/26/2019] [Indexed: 12/12/2022] Open
Abstract
Paucity of the survival motor neuron (SMN) protein triggers the oft-fatal infantile-onset motor neuron disorder, spinal muscular atrophy (SMA). Augmenting the protein is one means of treating SMA and recently led to FDA approval of an intrathecally delivered SMN-enhancing oligonucleotide currently in use. Notwithstanding the advent of this and other therapies for SMA, it is unclear whether the paralysis associated with the disease derives solely from dysfunctional motor neurons that may be efficiently targeted by restricted delivery of SMN-enhancing agents to the nervous system, or stems from broader defects of the motor unit, arguing for systemic SMN repletion. We investigated the disease-contributing effects of low SMN in one relevant peripheral organ - skeletal muscle - by selectively depleting the protein in only this tissue. We found that muscle deprived of SMN was profoundly damaged. Although a disease phenotype was not immediately obvious, persistent low levels of the protein eventually resulted in muscle fiber defects, neuromuscular junction abnormalities, compromised motor performance, and premature death. Importantly, restoring SMN after the onset of muscle pathology reversed disease. Our results provide the most compelling evidence yet for a direct contributing role of muscle in SMA and argue that an optimal therapy for the disease must be designed to treat this aspect of the dysfunctional motor unit.
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Affiliation(s)
- Jeong-Ki Kim
- Department of Pathology and Cell Biology and.,Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, New York, USA
| | - Narendra N Jha
- Department of Pathology and Cell Biology and.,Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, New York, USA
| | - Zhihua Feng
- Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
| | - Michelle R Faleiro
- Department of Pathology and Cell Biology and.,Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, New York, USA
| | - Claudia A Chiriboga
- Department of Neurology and.,Department of Pediatrics, Columbia University Medical Center, New York, New York, USA
| | - Lan Wei-Lapierre
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York, USA
| | - Robert T Dirksen
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York, USA
| | - Chien-Ping Ko
- Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
| | - Umrao R Monani
- Department of Pathology and Cell Biology and.,Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, New York, USA.,Department of Neurology and
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19
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Lauria F, Bernabò P, Tebaldi T, Groen EJN, Perenthaler E, Maniscalco F, Rossi A, Donzel D, Clamer M, Marchioretto M, Omersa N, Orri J, Dalla Serra M, Anderluh G, Quattrone A, Inga A, Gillingwater TH, Viero G. SMN-primed ribosomes modulate the translation of transcripts related to spinal muscular atrophy. Nat Cell Biol 2020; 22:1239-1251. [PMID: 32958857 PMCID: PMC7610479 DOI: 10.1038/s41556-020-00577-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 08/13/2020] [Indexed: 12/20/2022]
Abstract
The contribution of ribosome heterogeneity and ribosome-associated proteins to the molecular control of proteomes in health and disease remains unclear. Here, we demonstrate that survival motor neuron (SMN) protein-the loss of which causes the neuromuscular disease spinal muscular atrophy (SMA)-binds to ribosomes and that this interaction is tissue-dependent. SMN-primed ribosomes are preferentially positioned within the first five codons of a set of mRNAs that are enriched for translational enhancer sequences in the 5' untranslated region (UTR) and rare codons at the beginning of their coding sequence. These SMN-specific mRNAs are associated with neurogenesis, lipid metabolism, ubiquitination, chromatin regulation and translation. Loss of SMN induces ribosome depletion, especially at the beginning of the coding sequence of SMN-specific mRNAs, leading to impairment of proteins that are involved in motor neuron function and stability, including acetylcholinesterase. Thus, SMN plays a crucial role in the regulation of ribosome fluxes along mRNAs encoding proteins that are relevant to SMA pathogenesis.
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Affiliation(s)
- Fabio Lauria
- Institute of Biophysics, CNR Unit at Trento, Trento, Italy
| | - Paola Bernabò
- Institute of Biophysics, CNR Unit at Trento, Trento, Italy
| | - Toma Tebaldi
- Department CIBIO, University of Trento, Trento, Italy
- Yale Comprehensive Cancer Center, Yale University School of Medicine, New Haven, CT, USA
| | - Ewout Joan Nicolaas Groen
- Edinburgh Medical School, Biomedical Sciences & Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, Utrecht, the Netherlands
| | - Elena Perenthaler
- Institute of Biophysics, CNR Unit at Trento, Trento, Italy
- Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Federica Maniscalco
- Institute of Biophysics, CNR Unit at Trento, Trento, Italy
- Department CIBIO, University of Trento, Trento, Italy
| | | | - Deborah Donzel
- Institute of Biophysics, CNR Unit at Trento, Trento, Italy
| | | | | | - Neža Omersa
- National Institute of Chemistry, Ljubljana, Slovenia
| | - Julia Orri
- Institute of Biophysics, CNR Unit at Trento, Trento, Italy
- La Fundació Jesuïtes Educació, Barcelona, Spain
| | | | | | | | - Alberto Inga
- Department CIBIO, University of Trento, Trento, Italy
| | - Thomas Henry Gillingwater
- Edinburgh Medical School, Biomedical Sciences & Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
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20
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Nelvagal HR, Hurtado ML, Eaton SL, Kline RA, Lamont DJ, Sands MS, Wishart TM, Cooper JD. Comparative proteomic profiling reveals mechanisms for early spinal cord vulnerability in CLN1 disease. Sci Rep 2020; 10:15157. [PMID: 32938982 PMCID: PMC7495486 DOI: 10.1038/s41598-020-72075-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 08/26/2020] [Indexed: 01/11/2023] Open
Abstract
CLN1 disease is a fatal inherited neurodegenerative lysosomal storage disease of early childhood, caused by mutations in the CLN1 gene, which encodes the enzyme Palmitoyl protein thioesterase-1 (PPT-1). We recently found significant spinal pathology in Ppt1-deficient (Ppt1−/−) mice and human CLN1 disease that contributes to clinical outcome and precedes the onset of brain pathology. Here, we quantified this spinal pathology at 3 and 7 months of age revealing significant and progressive glial activation and vulnerability of spinal interneurons. Tandem mass tagged proteomic analysis of the spinal cord of Ppt1−/−and control mice at these timepoints revealed a significant neuroimmune response and changes in mitochondrial function, cell-signalling pathways and developmental processes. Comparing proteomic changes in the spinal cord and cortex at 3 months revealed many similarly affected processes, except the inflammatory response. These proteomic and pathological data from this largely unexplored region of the CNS may help explain the limited success of previous brain-directed therapies. These data also fundamentally change our understanding of the progressive, site-specific nature of CLN1 disease pathogenesis, and highlight the importance of the neuroimmune response. This should greatly impact our approach to the timing and targeting of future therapeutic trials for this and similar disorders.
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Affiliation(s)
- Hemanth R Nelvagal
- Division of Genetics and Genomic Medicine, Department of Pediatrics, Washington University in St Louis, School of Medicine, 660 S Euclid Ave, St Louis, MO, 63110, USA.,Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Maica Llavero Hurtado
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Samantha L Eaton
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Rachel A Kline
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Douglas J Lamont
- FingerPrints Proteomics Facility, College of Life Sciences, University of Dundee, Dundee, UK
| | - Mark S Sands
- Department of Genetics, Washington University in St Louis, School of Medicine, 660 S Euclid Ave, St Louis, MO, 63110, USA.,Department of Medicine, Washington University in St Louis, School of Medicine, 660 S Euclid Ave, St Louis, MO, 63110, USA
| | - Thomas M Wishart
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK
| | - Jonathan D Cooper
- Division of Genetics and Genomic Medicine, Department of Pediatrics, Washington University in St Louis, School of Medicine, 660 S Euclid Ave, St Louis, MO, 63110, USA. .,Department of Genetics, Washington University in St Louis, School of Medicine, 660 S Euclid Ave, St Louis, MO, 63110, USA. .,Department of Neurology, Washington University in St Louis, School of Medicine, 660 S Euclid Ave, St Louis, MO, 63110, USA. .,Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.
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21
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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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22
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Hensel N, Kubinski S, Claus P. The Need for SMN-Independent Treatments of Spinal Muscular Atrophy (SMA) to Complement SMN-Enhancing Drugs. Front Neurol 2020; 11:45. [PMID: 32117013 PMCID: PMC7009174 DOI: 10.3389/fneur.2020.00045] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 01/13/2020] [Indexed: 12/25/2022] Open
Abstract
Spinal Muscular Atrophy (SMA) is monogenic motoneuron disease caused by low levels of the Survival of Motoneuron protein (SMN). Recently, two different drugs were approved for the treatment of the disease. The antisense oligonucleotide Nusinersen/Spinraza® and the gene replacement therapy Onasemnogene Abeparvovec/Zolgensma® both enhance SMN levels. These treatments result in impressive benefits for the patients. However, there is a significant number of non-responders and an intervention delay has a strong negative impact on the efficacy. Obviously, later stages of motoneuron degeneration cannot be reversed by SMN-restoration. Therefore, complementary, SMN-independent strategies are needed which are able to address such SMN-irreversible degenerative processes. Those are defined as pathological alterations which are not reversed by SMN-restoration for a given dose and intervention delay. It is crucial to tailor SMN-independent approaches to the novel clinical situation with SMN-restoring treatments. On the molecular level, such SMN-irreversible changes become manifest in altered signaling modules as described by molecular systems biology. Based on our current knowledge about altered signaling, we introduce a network approach for an informed decision for the most potent SMN-independent treatment targets. Finally, we present recommendations for the identification of novel treatments which can be combined with SMN-restoring drugs.
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Affiliation(s)
- Niko Hensel
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany.,Center of Systems Neuroscience (ZSN), Hannover, Germany
| | - Sabrina Kubinski
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany.,Center of Systems Neuroscience (ZSN), Hannover, Germany
| | - Peter Claus
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany.,Center of Systems Neuroscience (ZSN), Hannover, Germany
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23
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Wirth B, Karakaya M, Kye MJ, Mendoza-Ferreira N. Twenty-Five Years of Spinal Muscular Atrophy Research: From Phenotype to Genotype to Therapy, and What Comes Next. Annu Rev Genomics Hum Genet 2020; 21:231-261. [PMID: 32004094 DOI: 10.1146/annurev-genom-102319-103602] [Citation(s) in RCA: 122] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Twenty-five years ago, the underlying genetic cause for one of the most common and devastating inherited diseases in humans, spinal muscular atrophy (SMA), was identified. Homozygous deletions or, rarely, subtle mutations of SMN1 cause SMA, and the copy number of the nearly identical copy gene SMN2 inversely correlates with disease severity. SMA has become a paradigm and a prime example of a monogenic neurological disorder that can be efficiently ameliorated or nearly cured by novel therapeutic strategies, such as antisense oligonucleotide or gene replacement therapy. These therapies enable infants to survive who might otherwise have died before the age of two and allow individuals who have never been able to sit or walk to do both. The major milestones on the road to these therapies were to understand the genetic cause and splice regulation of SMN genes, the disease's phenotype-genotype variability, the function of the protein and the main affected cellular pathways and tissues, the disease's pathophysiology through research on animal models, the windows of opportunity for efficient treatment, and how and when to treat patients most effectively.This review aims to bridge our knowledge from phenotype to genotype to therapy, not only highlighting the significant advances so far but also speculating about the future of SMA screening and treatment.
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Affiliation(s)
- Brunhilde Wirth
- Institute of Human Genetics, Center for Molecular Medicine Cologne and Center for Rare Diseases, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany;
| | - Mert Karakaya
- Institute of Human Genetics, Center for Molecular Medicine Cologne and Center for Rare Diseases, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany;
| | - Min Jeong Kye
- Institute of Human Genetics, Center for Molecular Medicine Cologne and Center for Rare Diseases, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany;
| | - Natalia Mendoza-Ferreira
- Institute of Human Genetics, Center for Molecular Medicine Cologne and Center for Rare Diseases, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany;
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24
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Morelli KH, Hatton CL, Harper SQ, Burgess RW. Gene therapies for axonal neuropathies: Available strategies, successes to date, and what to target next. Brain Res 2020; 1732:146683. [PMID: 32001243 DOI: 10.1016/j.brainres.2020.146683] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 01/23/2020] [Accepted: 01/24/2020] [Indexed: 12/20/2022]
Abstract
Nearly one-hundred loci in the human genome have been associated with different forms of Charcot-Marie-Tooth disease (CMT) and related inherited neuropathies. Despite this wealth of gene targets, treatment options are still extremely limited, and clear "druggable" pathways are not obvious for many of these mutations. However, recent advances in gene therapies are beginning to circumvent this challenge. Each type of CMT is a monogenic disorder, and the cellular targets are usually well-defined and typically include peripheral neurons or Schwann cells. In addition, the genetic mechanism is often also clear, with loss-of-function mutations requiring restoration of gene expression, and gain-of-function or dominant-negative mutations requiring silencing of the mutant allele. These factors combine to make CMT a good target for developing genetic therapies. Here we will review the state of relatively established gene therapy approaches, including viral vector-mediated gene replacement and antisense oligonucleotides for exon skipping, altering splicing, and gene knockdown. We will also describe earlier stage approaches for allele-specific knockdown and CRIPSR/Cas9 gene editing. We will next describe how these various approaches have been deployed in clinical and preclinical studies. Finally, we will evaluate various forms of CMT as candidates for gene therapy based on the current understanding of their genetics, cellular/tissue targets, validated animal models, and availability of patient populations and natural history data.
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Affiliation(s)
- Kathryn H Morelli
- The Jackson Laboratory, Bar Harbor, ME 04609, USA; The Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME 04469, USA
| | | | - Scott Q Harper
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA; Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Robert W Burgess
- The Jackson Laboratory, Bar Harbor, ME 04609, USA; The Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME 04469, USA.
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25
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Dangouloff T, Servais L. Clinical Evidence Supporting Early Treatment Of Patients With Spinal Muscular Atrophy: Current Perspectives. Ther Clin Risk Manag 2019; 15:1153-1161. [PMID: 31632042 PMCID: PMC6778729 DOI: 10.2147/tcrm.s172291] [Citation(s) in RCA: 127] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Accepted: 09/08/2019] [Indexed: 01/16/2023] Open
Abstract
Recent advances in the treatment of spinal muscular atrophy (SMA) have dramatically altered prognosis. Rather than a rapidly lethal disease, SMA type 1, the most severe form with the earliest onset of SMA, has become a disease in which long-term event-free survival with the acquisition of important motor milestones is likely. Prognosis for patients with SMA type 2 has shifted from slow and progressive deterioration to long-term stability. Nevertheless, there is a large heterogeneity in terms of clinical response to currently available treatments, ranging from absence of response to impressive improvement. The only factor identified that is predictive of treatment success is the age of the patient at the initiation of treatment, which is closely related to disease duration. The aim of this paper is to review available evidence that support early intervention using currently available treatment approaches.
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Affiliation(s)
- Tamara Dangouloff
- Division of Child Neurology, Centre de Références des Maladies Neuromusculaires, Department of Pediatrics, University Hospital Liège & University of Liège, Liège, Belgium
| | - Laurent Servais
- Division of Child Neurology, Centre de Références des Maladies Neuromusculaires, Department of Pediatrics, University Hospital Liège & University of Liège, Liège, Belgium
- MDUK Neuromuscular Center, Department of Paediatrics, University of Oxford, Oxford, UK
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26
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Quinlan KA, Reedich EJ, Arnold WD, Puritz AC, Cavarsan CF, Heckman CJ, DiDonato CJ. Hyperexcitability precedes motoneuron loss in the Smn2B/- mouse model of spinal muscular atrophy. J Neurophysiol 2019; 122:1297-1311. [PMID: 31365319 DOI: 10.1152/jn.00652.2018] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Spinal motoneuron dysfunction and loss are pathological hallmarks of the neuromuscular disease spinal muscular atrophy (SMA). Changes in motoneuron physiological function precede cell death, but how these alterations vary with disease severity and motoneuron maturational state is unknown. To address this question, we assessed the electrophysiology and morphology of spinal motoneurons of presymptomatic Smn2B/- mice older than 1 wk of age and tracked the timing of motor unit loss in this model using motor unit number estimation (MUNE). In contrast to other commonly used SMA mouse models, Smn2B/- mice exhibit more typical postnatal development until postnatal day (P)11 or 12 and have longer survival (~3 wk of age). We demonstrate that Smn2B/- motoneuron hyperexcitability, marked by hyperpolarization of the threshold voltage for action potential firing, was present at P9-10 and preceded the loss of motor units. Using MUNE studies, we determined that motor unit loss in this mouse model occurred 2 wk after birth. Smn2B/- motoneurons were also larger in size, which may reflect compensatory changes taking place during postnatal development. This work suggests that motoneuron hyperexcitability, marked by a reduced threshold for action potential firing, is a pathological change preceding motoneuron loss that is common to multiple models of severe SMA with different motoneuron maturational states. Our results indicate voltage-gated sodium channel activity may be altered in the disease process.NEW & NOTEWORTHY Changes in spinal motoneuron physiologic function precede cell death in spinal muscular atrophy (SMA), but how they vary with maturational state and disease severity remains unknown. This study characterized motoneuron and neuromuscular electrophysiology from the Smn2B/- model of SMA. Motoneurons were hyperexcitable at postnatal day (P)9-10, and specific electrophysiological changes in Smn2B/- motoneurons preceded functional motor unit loss at P14, as determined by motor unit number estimation studies.
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Affiliation(s)
- K A Quinlan
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island.,George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, Rhode Island.,Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - E J Reedich
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois.,Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois.,Human Molecular Genetics Program, Stanley Manne Children's Research Institute at Ann & Robert H. Lurie Children's Hospital, Chicago, Illinois
| | - W D Arnold
- Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, Ohio.,Department of Physical Medicine and Rehabilitation, The Ohio State University Wexner Medical Center, Columbus, Ohio.,Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, Ohio.,Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | - A C Puritz
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - C F Cavarsan
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island.,George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, Rhode Island
| | - C J Heckman
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois.,Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, Illinois.,Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - C J DiDonato
- Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois.,Human Molecular Genetics Program, Stanley Manne Children's Research Institute at Ann & Robert H. Lurie Children's Hospital, Chicago, Illinois
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27
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Slater CR. 'Fragmentation' of NMJs: a sign of degeneration or regeneration? A long journey with many junctions. Neuroscience 2019; 439:28-40. [PMID: 31129203 DOI: 10.1016/j.neuroscience.2019.05.017] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/07/2019] [Accepted: 05/07/2019] [Indexed: 12/13/2022]
Abstract
Mammalian neuromuscular junctions (NMJs) often consist of curved bands of synaptic contact, about 3-6 μm wide, which resemble pretzels. This contrasts with the NMJs of most animal species which consist of a cluster of separate synaptic spots, each of which is also about 3-6 μm across. In a number of situations, including a variety of disease states as well as normal ageing, mammalian NMJs acquire a more 'fragmented' appearance that resembles somewhat that of other species. This 'fragmentation' of the NMJ has sometimes been interpreted as a 'disintegration' or 'degeneration', with the suggestion that it might be associated with impaired neuromuscular transmission. An alternative view is that NMJ fragmentation is the outcome of a normal process by which the NMJ is maintained in an effective state. In this highly personal commentary, I cite a number of examples of this and point out that although the 'pretzel' form arises during normal development as a result of the sculpting of an immature synaptic 'plaque', in virtually all situations where new synaptic contact is established in adult mammals this occurs by the addition of new synaptic 'spots' rather than by the extension, or neoformation, of 'pretzels'. Further, where appropriate studies have been performed, no evidence of a correlation between the degree of fragmentation and the efficacy of transmission has emerged. It may therefore be more appropriate to consider NMJ 'fragmentation' as a form of regeneration, rather than of degeneration. This article is part of a Special Issue entitled: Honoring Ricardo Miledi - outstanding neuroscientist of XX-XXI centuries.
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Affiliation(s)
- Clarke R Slater
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK.
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28
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Groen EJN, Perenthaler E, Courtney NL, Jordan CY, Shorrock HK, van der Hoorn D, Huang YT, Murray LM, Viero G, Gillingwater TH. Temporal and tissue-specific variability of SMN protein levels in mouse models of spinal muscular atrophy. Hum Mol Genet 2019; 27:2851-2862. [PMID: 29790918 PMCID: PMC6077828 DOI: 10.1093/hmg/ddy195] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 05/14/2018] [Indexed: 02/02/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a progressive motor neuron disease caused by deleterious variants in SMN1 that lead to a marked decrease in survival motor neuron (SMN) protein expression. Humans have a second SMN gene (SMN2) that is almost identical to SMN1. However, due to alternative splicing the majority of SMN2 messenger ribonucleic acid (mRNA) is translated into a truncated, unstable protein that is quickly degraded. Because the presence of SMN2 provides a unique opportunity for therapy development in SMA patients, the mechanisms that regulate SMN2 splicing and mRNA expression have been elucidated in great detail. In contrast, how much SMN protein is produced at different developmental time points and in different tissues remains under-characterized. In this study, we addressed this issue by determining SMN protein expression levels at three developmental time points across six different mouse tissues and in two distinct mouse models of SMA (‘severe’ Taiwanese and ‘intermediate’ Smn2B/− mice). We found that, in healthy control mice, SMN protein expression was significantly influenced by both age and tissue type. When comparing mouse models of SMA, we found that, despite being transcribed from genetically different alleles, control SMN levels were relatively similar. In contrast, the degree of SMN depletion between tissues in SMA varied substantially over time and between the two models. These findings offer an explanation for the differential vulnerability of tissues and organs observed in SMA and further our understanding of the systemic and temporal requirements for SMN with direct relevance for developing effective therapies for SMA.
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Affiliation(s)
- Ewout J N Groen
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Elena Perenthaler
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Natalie L Courtney
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Crispin Y Jordan
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences
| | - Hannah K Shorrock
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Dinja van der Hoorn
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Yu-Ting Huang
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Lyndsay M Murray
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Gabriella Viero
- Institute of Biophysics, CNR Unit at Trento, 38123 Povo, Trento, Italy
| | - Thomas H Gillingwater
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH8 9XD, UK
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29
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Notch Signaling Mediates Astrocyte Abnormality in Spinal Muscular Atrophy Model Systems. Sci Rep 2019; 9:3701. [PMID: 30842449 PMCID: PMC6403369 DOI: 10.1038/s41598-019-39788-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 12/04/2018] [Indexed: 01/05/2023] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder characterized by the degeneration of spinal motor neurons and muscle atrophy. The disease is mainly caused by low level of the survival motor neuron (SMN) protein, which is coded by two genes, namely SMN1 and SMN2, but leads to selective spinal motor neuron degeneration when SMN1 gene is deleted or mutated. Previous reports have shown that SMN-protein-deficient astrocytes are abnormally abundant in the spinal cords of SMA model mice. However, the mechanism of the SMN- deficient astrocyte abnormality remains unclear. The purpose of this study is to identify the cellular signaling pathways associated with the SMN-deficient astrocyte abnormality and propose a candidate therapy tool that modulates signaling. In the present study, we found that the astrocyte density was increased around the central canal of the spinal cord in a mouse SMA model and we identified the dysregulation of Notch signaling which is a known mechanism that regulates astrocyte differentiation and proliferation, in the spinal cord in both early and late stages of SMA pathogenesis. Moreover, pharmacological inhibition of Notch signaling improved the motor functional deficits in SMA model mice. These findings indicate that dysregulated Notch signaling may be an underlying cause of SMA pathology.
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30
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Chaytow H, Huang YT, Gillingwater TH, Faller KME. The role of survival motor neuron protein (SMN) in protein homeostasis. Cell Mol Life Sci 2018; 75:3877-3894. [PMID: 29872871 PMCID: PMC6182345 DOI: 10.1007/s00018-018-2849-1] [Citation(s) in RCA: 111] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 05/30/2018] [Accepted: 05/31/2018] [Indexed: 12/11/2022]
Abstract
Ever since loss of survival motor neuron (SMN) protein was identified as the direct cause of the childhood inherited neurodegenerative disorder spinal muscular atrophy, significant efforts have been made to reveal the molecular functions of this ubiquitously expressed protein. Resulting research demonstrated that SMN plays important roles in multiple fundamental cellular homeostatic pathways, including a well-characterised role in the assembly of the spliceosome and biogenesis of ribonucleoproteins. More recent studies have shown that SMN is also involved in other housekeeping processes, including mRNA trafficking and local translation, cytoskeletal dynamics, endocytosis and autophagy. Moreover, SMN has been shown to influence mitochondria and bioenergetic pathways as well as regulate function of the ubiquitin-proteasome system. In this review, we summarise these diverse functions of SMN, confirming its key role in maintenance of the homeostatic environment of the cell.
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Affiliation(s)
- Helena Chaytow
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Yu-Ting Huang
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Thomas H Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK.
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK.
| | - Kiterie M E Faller
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
- Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK
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31
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Evaluation of potential effects of Plastin 3 overexpression and low-dose SMN-antisense oligonucleotides on putative biomarkers in spinal muscular atrophy mice. PLoS One 2018; 13:e0203398. [PMID: 30188931 PMCID: PMC6126849 DOI: 10.1371/journal.pone.0203398] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 08/20/2018] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVES Spinal muscular atrophy (SMA) is a devastating motor neuron disorder caused by homozygous loss of the survival motor neuron 1 (SMN1) gene and insufficient functional SMN protein produced by the SMN2 copy gene. Additional genetic protective modifiers such as Plastin 3 (PLS3) can counteract SMA pathology despite insufficient SMN protein. Recently, Spinraza, an SMN antisense oligonucleotide (ASO) that restores full-length SMN2 transcripts, has been FDA- and EMA-approved for SMA therapy. Hence, the availability of biomarkers allowing a reliable monitoring of disease and therapy progression would be of great importance. Our objectives were (i) to analyse the feasibility of SMN and of six SMA biomarkers identified by the BforSMA study in the Taiwanese SMA mouse model, (ii) to analyse the effect of PLS3 overexpression on these biomarkers, and (iii) to assess the impact of low-dose SMN-ASO therapy on the level of SMN and the six biomarkers. METHODS At P10 and P21, the level of SMN and six putative biomarkers were compared among SMA, heterozygous and wild type mice, with or without PLS3 overexpression, and with or without presymptomatic low-dose SMN-ASO subcutaneous injection. SMN levels were measured in whole blood by ECL immunoassay and of six SMA putative biomarkers, namely Cartilage Oligomeric Matrix Protein (COMP), Dipeptidyl Peptidase 4 (DPP4), Tetranectin (C-type Lectin Family 3 Member B, CLEC3B), Osteopontin (Secreted Phosphoprotein 1, SPP1), Vitronectin (VTN) and Fetuin A (Alpha 2-HS Glycoprotein, AHSG) in plasma. RESULTS SMN levels were significantly discernible between SMA, heterozygous and wild type mice. However, no significant differences were measured upon low-dose SMN-ASO treatment compared to untreated animals. Of the six biomarkers, only COMP and DPP4 showed high and SPP1 moderate correlation with the SMA phenotype. PLS3 overexpression neither influenced the SMN level nor the six biomarkers, supporting the hypothesis that PLS3 acts as an independent protective modifier.
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32
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Cerveró C, Blasco A, Tarabal O, Casanovas A, Piedrafita L, Navarro X, Esquerda JE, Calderó J. Glial Activation and Central Synapse Loss, but Not Motoneuron Degeneration, Are Prevented by the Sigma-1 Receptor Agonist PRE-084 in the Smn2B/- Mouse Model of Spinal Muscular Atrophy. J Neuropathol Exp Neurol 2018; 77:577-597. [PMID: 29767748 DOI: 10.1093/jnen/nly033] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Spinal muscular atrophy (SMA) is characterized by the loss of α-motoneurons (MNs) with concomitant muscle denervation. MN excitability and vulnerability to disease are particularly regulated by cholinergic synaptic afferents (C-boutons), in which Sigma-1 receptor (Sig1R) is concentrated. Alterations in Sig1R have been associated with MN degeneration. Here, we investigated whether a chronic treatment with the Sig1R agonist PRE-084 was able to exert beneficial effects on SMA. We used a model of intermediate SMA, the Smn2B/- mouse, in which we performed a detailed characterization of the histopathological changes that occur throughout the disease. We report that Smn2B/- mice exhibited qualitative differences in major alterations found in mouse models of severe SMA: Smn2B/- animals showed more prominent MN degeneration, early motor axon alterations, marked changes in sensory neurons, and later MN deafferentation that correlated with conspicuous reactive gliosis and altered neuroinflammatory M1/M2 microglial balance. PRE-084 attenuated reactive gliosis, mitigated M1/M2 imbalance, and prevented MN deafferentation in Smn2B/- mice. These effects were also observed in a severe SMA model, the SMNΔ7 mouse. However, the prevention of gliosis and MN deafferentation promoted by PRE-084 were not accompanied by any improvements in clinical outcome or other major pathological changes found in SMA mice.
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Affiliation(s)
- Clàudia Cerveró
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Lleida, Catalonia, Spain
| | - Alba Blasco
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Lleida, Catalonia, Spain
| | - Olga Tarabal
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Lleida, Catalonia, Spain
| | - Anna Casanovas
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Lleida, Catalonia, Spain
| | - Lídia Piedrafita
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Lleida, Catalonia, Spain
| | - Xavier Navarro
- Group of Neuroplasticity and Regeneration, Institute of Neurosciences and Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona and CIBERNED, Bellaterra, Catalonia, Spain
| | - Josep E Esquerda
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Lleida, Catalonia, Spain
| | - Jordi Calderó
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Lleida, Catalonia, Spain
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33
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Bernabò P, Tebaldi T, Groen EJN, Lane FM, Perenthaler E, Mattedi F, Newbery HJ, Zhou H, Zuccotti P, Potrich V, Shorrock HK, Muntoni F, Quattrone A, Gillingwater TH, Viero G. In Vivo Translatome Profiling in Spinal Muscular Atrophy Reveals a Role for SMN Protein in Ribosome Biology. Cell Rep 2018; 21:953-965. [PMID: 29069603 PMCID: PMC5668566 DOI: 10.1016/j.celrep.2017.10.010] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 07/22/2017] [Accepted: 10/02/2017] [Indexed: 12/13/2022] Open
Abstract
Genetic alterations impacting ubiquitously expressed proteins involved in RNA metabolism often result in neurodegenerative conditions, with increasing evidence suggesting that translation defects can contribute to disease. Spinal muscular atrophy (SMA) is a neuromuscular disease caused by low levels of SMN protein, whose role in pathogenesis remains unclear. Here, we identified in vivo and in vitro translation defects that are cell autonomous and SMN dependent. By determining in parallel the in vivo transcriptome and translatome in SMA mice, we observed a robust decrease in translation efficiency arising during early stages of disease. We provide a catalogue of RNAs with altered translation efficiency, identifying ribosome biology and translation as central processes affected by SMN depletion. This was further supported by a decrease in the number of ribosomes in SMA motor neurons in vivo. Overall, our findings suggest ribosome biology as an important, yet largely overlooked, factor in motor neuron degeneration. Polysomal profiling reveals translation defects in SMA mice Translation defects are SMN dependent and cell autonomous Translation efficiency alterations highlight defects in ribosome biology The number of axonal ribosomes is decreased in SMA in vivo
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Affiliation(s)
- Paola Bernabò
- Institute of Biophysics, CNR Unit at Trento, Via Sommarive 18, 38123 Povo (Trento), Italy
| | - Toma Tebaldi
- Centre for Integrative Biology, University of Trento, Via Sommarive 9, 38123 Povo (Trento), Italy
| | - Ewout J N Groen
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Hugh Robson Building, 15 George Square, EH8 9XD Edinburgh, UK; Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Hugh Robson Building, 15 George Square, EH8 9XD Edinburgh, UK
| | - Fiona M Lane
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Hugh Robson Building, 15 George Square, EH8 9XD Edinburgh, UK; Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Hugh Robson Building, 15 George Square, EH8 9XD Edinburgh, UK
| | - Elena Perenthaler
- Institute of Biophysics, CNR Unit at Trento, Via Sommarive 18, 38123 Povo (Trento), Italy
| | - Francesca Mattedi
- Institute of Biophysics, CNR Unit at Trento, Via Sommarive 18, 38123 Povo (Trento), Italy
| | - Helen J Newbery
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Hugh Robson Building, 15 George Square, EH8 9XD Edinburgh, UK; Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Hugh Robson Building, 15 George Square, EH8 9XD Edinburgh, UK
| | - Haiyan Zhou
- Dubowitz Neuromuscular Centre, Great Ormond Street Institute of Child Health, University College London 30, Guilford Street, WC1N 1EH London, UK
| | - Paola Zuccotti
- Centre for Integrative Biology, University of Trento, Via Sommarive 9, 38123 Povo (Trento), Italy
| | - Valentina Potrich
- Centre for Integrative Biology, University of Trento, Via Sommarive 9, 38123 Povo (Trento), Italy
| | - Hannah K Shorrock
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Hugh Robson Building, 15 George Square, EH8 9XD Edinburgh, UK; Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Hugh Robson Building, 15 George Square, EH8 9XD Edinburgh, UK
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, Great Ormond Street Institute of Child Health, University College London 30, Guilford Street, WC1N 1EH London, UK
| | - Alessandro Quattrone
- Centre for Integrative Biology, University of Trento, Via Sommarive 9, 38123 Povo (Trento), Italy.
| | - Thomas H Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Hugh Robson Building, 15 George Square, EH8 9XD Edinburgh, UK; Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Hugh Robson Building, 15 George Square, EH8 9XD Edinburgh, UK.
| | - Gabriella Viero
- Institute of Biophysics, CNR Unit at Trento, Via Sommarive 18, 38123 Povo (Trento), Italy.
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34
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Thompson LW, Morrison KD, Shirran SL, Groen EJN, Gillingwater TH, Botting CH, Sleeman JE. Neurochondrin interacts with the SMN protein suggesting a novel mechanism for spinal muscular atrophy pathology. J Cell Sci 2018; 131:jcs.211482. [PMID: 29507115 PMCID: PMC5963842 DOI: 10.1242/jcs.211482] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 02/16/2018] [Indexed: 12/15/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an inherited neurodegenerative condition caused by a reduction in the amount of functional survival motor neuron (SMN) protein. SMN has been implicated in transport of mRNA in neural cells for local translation. We previously identified microtubule-dependent mobile vesicles rich in SMN and SNRPB, a member of the Sm family of small nuclear ribonucleoprotein (snRNP)-associated proteins, in neural cells. By comparing the interactomes of SNRPB and SNRPN, a neural-specific Sm protein, we now show that the essential neural protein neurochondrin (NCDN) interacts with Sm proteins and SMN in the context of mobile vesicles in neurites. NCDN has roles in protein localisation in neural cells and in maintenance of cell polarity. NCDN is required for the correct localisation of SMN, suggesting they may both be required for formation and transport of trafficking vesicles. NCDN may have potential as a therapeutic target for SMA together with, or in place of the targeting of SMN expression. This article has an associated First Person interview with the first author of the paper. Highlighted Article: The essential neural protein neurochondrin interacts with the spinal muscular atrophy (SMA) protein SMN in cell lines and in mice. This might be relevant to the molecular pathology of SMA.
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Affiliation(s)
- Luke W Thompson
- School of Biology, University of St Andrews, BSRC Complex, North Haugh St Andrews, KY16 9ST, UK
| | - Kim D Morrison
- School of Biology, University of St Andrews, BSRC Complex, North Haugh St Andrews, KY16 9ST, UK
| | - Sally L Shirran
- School of Biology, University of St Andrews, BSRC Complex, North Haugh St Andrews, KY16 9ST, UK
| | - Ewout J N Groen
- Edinburgh Medical School, Biomedical Sciences and Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Thomas H Gillingwater
- Edinburgh Medical School, Biomedical Sciences and Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Catherine H Botting
- School of Biology, University of St Andrews, BSRC Complex, North Haugh St Andrews, KY16 9ST, UK
| | - Judith E Sleeman
- School of Biology, University of St Andrews, BSRC Complex, North Haugh St Andrews, KY16 9ST, UK
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35
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Piras A, Schiaffino L, Boido M, Valsecchi V, Guglielmotto M, De Amicis E, Puyal J, Garcera A, Tamagno E, Soler RM, Vercelli A. Inhibition of autophagy delays motoneuron degeneration and extends lifespan in a mouse model of spinal muscular atrophy. Cell Death Dis 2017; 8:3223. [PMID: 29259166 PMCID: PMC5870600 DOI: 10.1038/s41419-017-0086-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Revised: 09/12/2017] [Accepted: 10/05/2017] [Indexed: 12/26/2022]
Abstract
Spinal muscular atrophy (SMA) is a recessive autosomal neuromuscular disease, due to homozygous mutations or deletions in the telomeric survival motoneuron gene 1 (SMN1). SMA is characterized by motor impairment, muscle atrophy, and premature death following motor neuron (MN) degeneration. Emerging evidence suggests that dysregulation of autophagy contributes to MN degeneration. We here investigated the role of autophagy in the SMNdelta7 mouse model of SMA II (intermediate form of the disease) which leads to motor impairment by postnatal day 5 (P5) and to death by P13. We first showed by immunoblots that Beclin 1 and LC3-II expression levels increased in the lumbar spinal cord of the SMA pups. Electron microscopy and immunofluorescence studies confirmed that autophagic markers were enhanced in the ventral horn of SMA pups. To clarify the role of autophagy, we administered intracerebroventricularly (at P3) either an autophagy inhibitor (3-methyladenine, 3-MA), or an autophagy inducer (rapamycin) in SMA pups. Motor behavior was assessed daily with different tests: tail suspension, righting reflex, and hindlimb suspension tests. 3-MA significantly improved motor performance, extended the lifespan, and delayed MN death in lumbar spinal cord (10372.36 ± 2716 MNs) compared to control-group (5148.38 ± 94 MNs). Inhibition of autophagy by 3-MA suppressed autophagosome formation, reduced the apoptotic activation (cleaved caspase-3 and Bcl2) and the appearance of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive neurons, underlining that apoptosis and autophagy pathways are intricately intertwined. Therefore, autophagy is likely involved in MN death in SMA II, suggesting that it might represent a promising target for delaying the progression of SMA in humans as well.
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Affiliation(s)
- Antonio Piras
- Department of Neuroscience, University of Torino, Torino, Italy. .,Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Torino, Torino, Italy. .,Karolinska Institutet, Dept NVS, Center for Alzheimer Research, Division for Neurogeriatrics, 141 57, Huddinge, Sweden.
| | - Lorenzo Schiaffino
- Department of Neuroscience, University of Torino, Torino, Italy.,Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Torino, Torino, Italy
| | - Marina Boido
- Department of Neuroscience, University of Torino, Torino, Italy.,Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Torino, Torino, Italy
| | - Valeria Valsecchi
- Department of Neuroscience, University of Torino, Torino, Italy.,Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Torino, Torino, Italy
| | - Michela Guglielmotto
- Department of Neuroscience, University of Torino, Torino, Italy.,Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Torino, Torino, Italy
| | - Elena De Amicis
- Department of Neuroscience, University of Torino, Torino, Italy.,Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Torino, Torino, Italy
| | - Julien Puyal
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Ana Garcera
- Unitat de Senyalització Neuronal, Dep. Medicina Experimental, Universitat de Lleida-IRBLLEIDA, Rovira Roure 80, 25198, Lleida, Spain
| | - Elena Tamagno
- Department of Neuroscience, University of Torino, Torino, Italy.,Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Torino, Torino, Italy
| | - Rosa M Soler
- Unitat de Senyalització Neuronal, Dep. Medicina Experimental, Universitat de Lleida-IRBLLEIDA, Rovira Roure 80, 25198, Lleida, Spain
| | - Alessandro Vercelli
- Department of Neuroscience, University of Torino, Torino, Italy.,Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Torino, Torino, Italy
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36
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Tosolini AP, Sleigh JN. Motor Neuron Gene Therapy: Lessons from Spinal Muscular Atrophy for Amyotrophic Lateral Sclerosis. Front Mol Neurosci 2017; 10:405. [PMID: 29270111 PMCID: PMC5725447 DOI: 10.3389/fnmol.2017.00405] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 11/21/2017] [Indexed: 12/11/2022] Open
Abstract
Spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS) are severe nervous system diseases characterized by the degeneration of lower motor neurons. They share a number of additional pathological, cellular, and genetic parallels suggesting that mechanistic and clinical insights into one disorder may have value for the other. While there are currently no clinical ALS gene therapies, the splice-switching antisense oligonucleotide, nusinersen, was recently approved for SMA. This milestone was achieved through extensive pre-clinical research and patient trials, which together have spawned fundamental insights into motor neuron gene therapy. We have thus tried to distil key information garnered from SMA research, in the hope that it may stimulate a more directed approach to ALS gene therapy. Not only must the type of therapeutic (e.g., antisense oligonucleotide vs. viral vector) be sensibly selected, but considerable thought must be applied to the where, which, what, and when in order to enhance treatment benefit: to where (cell types and tissues) must the drug be delivered and how can this be best achieved? Which perturbed pathways must be corrected and can they be concurrently targeted? What dosing regime and concentration should be used? When should medication be administered? These questions are intuitive, but central to identifying and optimizing a successful gene therapy. Providing definitive solutions to these quandaries will be difficult, but clear thinking about therapeutic testing is necessary if we are to have the best chance of developing viable ALS gene therapies and improving upon early generation SMA treatments.
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Affiliation(s)
- Andrew P Tosolini
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
| | - James N Sleigh
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
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37
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Kim JK, Caine C, Awano T, Herbst R, Monani UR. Motor neuronal repletion of the NMJ organizer, Agrin, modulates the severity of the spinal muscular atrophy disease phenotype in model mice. Hum Mol Genet 2017; 26:2377-2385. [PMID: 28379354 DOI: 10.1093/hmg/ddx124] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 03/23/2017] [Indexed: 11/14/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a common and often fatal neuromuscular disorder caused by low levels of the Survival Motor Neuron (SMN) protein. Amongst the earliest detectable consequences of SMN deficiency are profound defects of the neuromuscular junctions (NMJs). In model mice these synapses appear disorganized, fail to mature and are characterized by poorly arborized nerve terminals. Given one role of the SMN protein in orchestrating the assembly of spliceosomal snRNP particles and subsequently regulating the alternative splicing of pre-mRNAs, a plausible link between SMN function and the distal neuromuscular SMA phenotype is an incorrectly spliced transcript or transcripts involved in establishing or maintaining NMJ structure. In this study, we explore the effects of one such transcript-Z+Agrin-known to be a critical organizer of the NMJ. We confirm that low SMN protein reduces motor neuronal levels of Z+Agrin. Repletion of this isoform of Agrin in the motor neurons of SMA model mice increases muscle fiber size, enhances the post-synaptic NMJ area, reduces the abnormal accumulation of intermediate filaments in nerve terminals of the neuromuscular synapse and improves the innervation of muscles. While these effects are independent of changes in SMN levels or increases in motor neuron numbers they nevertheless have a significant effect on the overall disease phenotype, enhancing mean survival in severely affected SMA model mice by ∼40%. We conclude that Agrin is an important target of the SMN protein and that mitigating NMJ defects may be one strategy in treating human spinal muscular atrophy.
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Affiliation(s)
- Jeong-Ki Kim
- Department of Pathology and Cell Biology.,Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, NY 10032, USA
| | - Charlotte Caine
- Department of Pathology and Cell Biology.,Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, NY 10032, USA
| | - Tomoyuki Awano
- Department of Pathology and Cell Biology.,Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, NY 10032, USA
| | - Ruth Herbst
- Center for Brain Research.,Institute of Immunology, Medical University of Vienna, 1090 Vienna
| | - Umrao R Monani
- Department of Pathology and Cell Biology.,Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, NY 10032, USA.,Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA
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38
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Neuropilin 1 sequestration by neuropathogenic mutant glycyl-tRNA synthetase is permissive to vascular homeostasis. Sci Rep 2017; 7:9216. [PMID: 28835631 PMCID: PMC5569042 DOI: 10.1038/s41598-017-10005-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 07/27/2017] [Indexed: 12/11/2022] Open
Abstract
The mechanism by which dominantly inherited mutations in the housekeeping gene GARS, which encodes glycyl-tRNA synthetase (GlyRS), mediate selective peripheral nerve toxicity resulting in Charcot-Marie-Tooth disease type 2D (CMT2D) is still largely unresolved. The transmembrane receptor protein neuropilin 1 (Nrp1) was recently identified as an aberrant extracellular binding partner of mutant GlyRS. Formation of the Nrp1/mutant GlyRS complex antagonises Nrp1 interaction with one of its main natural ligands, vascular endothelial growth factor-A (VEGF-A), contributing to neurodegeneration. However, reduced extracellular binding of VEGF-A to Nrp1 is known to disrupt post-natal blood vessel development and growth. We therefore analysed the vascular system at early and late symptomatic time points in CMT2D mouse muscles, retina, and sciatic nerve, as well as in embryonic hindbrain. Mutant tissues show no difference in blood vessel diameter, density/growth, and branching from embryonic development to three months, spanning the duration over which numerous sensory and neuromuscular phenotypes manifest. Our findings indicate that mutant GlyRS-mediated disruption of Nrp1/VEGF-A signalling is permissive to maturation and maintenance of the vasculature in CMT2D mice.
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39
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Howell MD, Ottesen EW, Singh NN, Anderson RL, Seo J, Sivanesan S, Whitley EM, Singh RN. TIA1 is a gender-specific disease modifier of a mild mouse model of spinal muscular atrophy. Sci Rep 2017; 7:7183. [PMID: 28775379 PMCID: PMC5543135 DOI: 10.1038/s41598-017-07468-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 06/26/2017] [Indexed: 02/08/2023] Open
Abstract
Spinal muscular atrophy (SMA) is caused by deletions or mutations of Survival Motor Neuron 1 (SMN1) gene. The nearly identical SMN2 cannot compensate for SMN1 loss due to exon 7 skipping. The allele C (C +/+) mouse recapitulates a mild SMA-like phenotype and offers an ideal system to monitor the role of disease-modifying factors over a long time. T-cell-restricted intracellular antigen 1 (TIA1) regulates SMN exon 7 splicing. TIA1 is reported to be downregulated in obese patients, although it is not known if the effect is gender-specific. We show that female Tia1-knockout (Tia1 -/-) mice gain significant body weight (BW) during early postnatal development. We next examined the effect of Tia1 deletion in novel C +/+/Tia1 -/- mice. Underscoring the opposing effects of Tia1 deletion and low SMN level on BW gain, both C +/+ and C +/+/Tia1 -/- females showed similar BW gain trajectory at all time points during our study. We observed early tail necrosis in C +/+/Tia1 -/- females but not in males. We show enhanced impairment of male reproductive organ development and exacerbation of the C +/+/Tia1 -/- testis transcriptome. Our findings implicate a protein factor as a gender-specific modifier of a mild mouse model of SMA.
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Affiliation(s)
- Matthew D Howell
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, 50011, USA
| | - Eric W Ottesen
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, 50011, USA
| | - Natalia N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, 50011, USA
| | - Rachel L Anderson
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, 50011, USA
| | - Joonbae Seo
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, 50011, USA
- Division of Endocrinology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | | | - Elizabeth M Whitley
- Department of Veterinary Pathology, Iowa State University, Ames, IA, 50011-1250, USA
- Pathogenesis, LLC, Gainesville, Florida, 32614, USA
| | - Ravindra N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, 50011, USA.
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40
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Hosseinibarkooie S, Schneider S, Wirth B. Advances in understanding the role of disease-associated proteins in spinal muscular atrophy. Expert Rev Proteomics 2017. [PMID: 28635376 DOI: 10.1080/14789450.2017.1345631] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
INTRODUCTION Spinal muscular atrophy (SMA) is a neurodegenerative disorder characterized by alpha motor neuron loss in the spinal cord due to reduced survival motor neuron (SMN) protein level. While the genetic basis of SMA is well described, the specific molecular pathway underlying SMA is still not fully understood. Areas covered: This review discusses the recent advancements in understanding the molecular pathways in SMA using different omics approaches and genetic modifiers identified in both vertebrate and invertebrate systems. The findings that are summarized in this article were deduced from original articles and reviews with a particular focus on the latest advancements in the field. Expert commentary: The identification of genetic modifiers such as PLS3 and NCALD in humans or of SMA modulators such as Elavl4 (HuD), Copa, Uba1, Mapk10 (Jnk3), Nrxn2 and Tmem41b (Stasimon) in various SMA animal models improved our knowledge of impaired cellular pathways in SMA. Inspiration from modifier genes and their functions in motor neuron and neuromuscular junctions may open a new avenue for future SMA combinatorial therapies.
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Affiliation(s)
- Seyyedmohsen Hosseinibarkooie
- a Institute of Human Genetics , University of Cologne , Cologne , Germany.,b Center for Molecular Medicine Cologne , University of Cologne , Cologne , Germany.,c Institute for Genetics , University of Cologne , Cologne , Germany
| | - Svenja Schneider
- a Institute of Human Genetics , University of Cologne , Cologne , Germany.,b Center for Molecular Medicine Cologne , University of Cologne , Cologne , Germany.,c Institute for Genetics , University of Cologne , Cologne , Germany
| | - Brunhilde Wirth
- a Institute of Human Genetics , University of Cologne , Cologne , Germany.,b Center for Molecular Medicine Cologne , University of Cologne , Cologne , Germany.,c Institute for Genetics , University of Cologne , Cologne , Germany.,d Center for Rare Diseases Cologne , University Hospital of Cologne, University of Cologne , Cologne , Germany
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41
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Christie-Brown V, Mitchell J, Talbot K. The SMA Trust: the role of a disease-focused research charity in developing treatments for SMA. Gene Ther 2017; 24:544-546. [PMID: 28561814 DOI: 10.1038/gt.2017.47] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 05/09/2017] [Accepted: 05/10/2017] [Indexed: 02/04/2023]
Abstract
SMA is a rare hereditary neuromuscular disease that causes weakness and muscle wasting as a result of the loss of spinal motor neurons. In its most severe form, SMA is the commonest genetic cause of death in infants, and children with less severe forms of SMA face the prospect of lifelong disability from progressive muscle wasting, loss of mobility and limb weakness. The initial discovery of the defective gene has been followed by major advances in our understanding of the genetic, cellular and molecular basis of SMA, providing the foundation for a range of approaches to treatment, including gene therapy, antisense oligonucleotide treatments and more traditional drug-based approaches to slow or halt disease progression. The approval by the US Food and Drug Administration (FDA) of Spinraza (nusinersen), the first targeted treatment for spinal muscular atrophy (SMA), is a historic moment. Disease-focused research charities, such as The SMA Trust (UK), continue to have a crucial role in promoting the development of additional treatments for SMA, both by funding translational research and by promoting links between researchers, people living with SMA and other stakeholders, including pharmaceutical companies and healthcare providers.
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42
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Rietz A, Li H, Quist KM, Cherry JJ, Lorson CL, Burnett BG, Kern NL, Calder AN, Fritsche M, Lusic H, Boaler PJ, Choi S, Xing X, Glicksman MA, Cuny GD, Androphy EJ, Hodgetts KJ. Discovery of a Small Molecule Probe That Post-Translationally Stabilizes the Survival Motor Neuron Protein for the Treatment of Spinal Muscular Atrophy. J Med Chem 2017; 60:4594-4610. [PMID: 28481536 DOI: 10.1021/acs.jmedchem.6b01885] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Spinal muscular atrophy (SMA) is the leading genetic cause of infant death. We previously developed a high-throughput assay that employs an SMN2-luciferase reporter allowing identification of compounds that act transcriptionally, enhance exon recognition, or stabilize the SMN protein. We describe optimization and characterization of an analog suitable for in vivo testing. Initially, we identified analog 4m that had good in vitro properties but low plasma and brain exposure in a mouse PK experiment due to short plasma stability; this was overcome by reversing the amide bond and changing the heterocycle. Thiazole 27 showed excellent in vitro properties and a promising mouse PK profile, making it suitable for in vivo testing. This series post-translationally stabilizes the SMN protein, unrelated to global proteasome or autophagy inhibition, revealing a novel therapeutic mechanism that should complement other modalities for treatment of SMA.
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Affiliation(s)
- Anne Rietz
- Department of Dermatology, Indiana University School of Medicine , Indianapolis, Indiana 46202, United States
| | - Hongxia Li
- Department of Dermatology, Indiana University School of Medicine , Indianapolis, Indiana 46202, United States
| | - Kevin M Quist
- Department of Dermatology, Indiana University School of Medicine , Indianapolis, Indiana 46202, United States
| | - Jonathan J Cherry
- Department of Dermatology, Indiana University School of Medicine , Indianapolis, Indiana 46202, United States
| | - Christian L Lorson
- Department of Veterinary Pathobiology, Bond Life Sciences Center, University of Missouri , Columbia, Missouri 65201, United States
| | - Barrington G Burnett
- Department of Anatomy, Physiology and Genetics, F. Edward Hebert School of Medicine, Uniformed Services University of the Health Sciences , Bethesda, Maryland 20814, United States
| | - Nicholas L Kern
- Laboratory for Drug Discovery in Neurodegeneration, Brigham & Women's Hospital and Harvard Medical School , 65 Landsdowne Street, Cambridge, Massachusetts 02139, United States
| | - Alyssa N Calder
- Laboratory for Drug Discovery in Neurodegeneration, Brigham & Women's Hospital and Harvard Medical School , 65 Landsdowne Street, Cambridge, Massachusetts 02139, United States
| | - Melanie Fritsche
- Laboratory for Drug Discovery in Neurodegeneration, Brigham & Women's Hospital and Harvard Medical School , 65 Landsdowne Street, Cambridge, Massachusetts 02139, United States
| | - Hrvoje Lusic
- Laboratory for Drug Discovery in Neurodegeneration, Brigham & Women's Hospital and Harvard Medical School , 65 Landsdowne Street, Cambridge, Massachusetts 02139, United States
| | - Patrick J Boaler
- Laboratory for Drug Discovery in Neurodegeneration, Brigham & Women's Hospital and Harvard Medical School , 65 Landsdowne Street, Cambridge, Massachusetts 02139, United States
| | - Sungwoon Choi
- Laboratory for Drug Discovery in Neurodegeneration, Brigham & Women's Hospital and Harvard Medical School , 65 Landsdowne Street, Cambridge, Massachusetts 02139, United States
| | - Xuechao Xing
- Laboratory for Drug Discovery in Neurodegeneration, Brigham & Women's Hospital and Harvard Medical School , 65 Landsdowne Street, Cambridge, Massachusetts 02139, United States
| | - Marcie A Glicksman
- Laboratory for Drug Discovery in Neurodegeneration, Brigham & Women's Hospital and Harvard Medical School , 65 Landsdowne Street, Cambridge, Massachusetts 02139, United States
| | - Gregory D Cuny
- Laboratory for Drug Discovery in Neurodegeneration, Brigham & Women's Hospital and Harvard Medical School , 65 Landsdowne Street, Cambridge, Massachusetts 02139, United States
| | - Elliot J Androphy
- Department of Dermatology, Indiana University School of Medicine , Indianapolis, Indiana 46202, United States
| | - Kevin J Hodgetts
- Laboratory for Drug Discovery in Neurodegeneration, Brigham & Women's Hospital and Harvard Medical School , 65 Landsdowne Street, Cambridge, Massachusetts 02139, United States
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Shabanpoor F, Hammond SM, Abendroth F, Hazell G, Wood MJA, Gait MJ. Identification of a Peptide for Systemic Brain Delivery of a Morpholino Oligonucleotide in Mouse Models of Spinal Muscular Atrophy. Nucleic Acid Ther 2017; 27:130-143. [PMID: 28118087 PMCID: PMC5467147 DOI: 10.1089/nat.2016.0652] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Splice-switching antisense oligonucleotides are emerging treatments for neuromuscular diseases, with several splice-switching oligonucleotides (SSOs) currently undergoing clinical trials such as for Duchenne muscular dystrophy (DMD) and spinal muscular atrophy (SMA). However, the development of systemically delivered antisense therapeutics has been hampered by poor tissue penetration and cellular uptake, including crossing of the blood–brain barrier (BBB) to reach targets in the central nervous system (CNS). For SMA application, we have investigated the ability of various BBB-crossing peptides for CNS delivery of a splice-switching phosphorodiamidate morpholino oligonucleotide (PMO) targeting survival motor neuron 2 (SMN2) exon 7 inclusion. We identified a branched derivative of the well-known ApoE (141–150) peptide, which as a PMO conjugate was capable of exon inclusion in the CNS following systemic administration, leading to an increase in the level of full-length SMN2 transcript. Treatment of newborn SMA mice with this peptide-PMO (P-PMO) conjugate resulted in a significant increase in the average lifespan and gains in weight, muscle strength, and righting reflexes. Systemic treatment of adult SMA mice with this newly identified P-PMO also resulted in small but significant increases in the levels of SMN2 pre-messenger RNA (mRNA) exon inclusion in the CNS and peripheral tissues. This work provides proof of principle for the ability to select new peptide paradigms to enhance CNS delivery and activity of a PMO SSO through use of a peptide-based delivery platform for the treatment of SMA potentially extending to other neuromuscular and neurodegenerative diseases.
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Affiliation(s)
- Fazel Shabanpoor
- 1 Medical Research Council, Laboratory of Molecular Biology , Cambridge, United Kingdom
| | - Suzan M Hammond
- 2 Department of Physiology, Anatomy, and Genetics, University of Oxford , Oxford, United Kingdom
| | - Frank Abendroth
- 1 Medical Research Council, Laboratory of Molecular Biology , Cambridge, United Kingdom
| | - Gareth Hazell
- 2 Department of Physiology, Anatomy, and Genetics, University of Oxford , Oxford, United Kingdom
| | - Matthew J A Wood
- 2 Department of Physiology, Anatomy, and Genetics, University of Oxford , Oxford, United Kingdom
| | - Michael J Gait
- 1 Medical Research Council, Laboratory of Molecular Biology , Cambridge, United Kingdom
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Hosseinibarkooie S, Peters M, Torres-Benito L, Rastetter R, Hupperich K, Hoffmann A, Mendoza-Ferreira N, Kaczmarek A, Janzen E, Milbradt J, Lamkemeyer T, Rigo F, Bennett C, Guschlbauer C, Büschges A, Hammerschmidt M, Riessland M, Kye M, Clemen C, Wirth B. The Power of Human Protective Modifiers: PLS3 and CORO1C Unravel Impaired Endocytosis in Spinal Muscular Atrophy and Rescue SMA Phenotype. Am J Hum Genet 2016; 99:647-665. [PMID: 27499521 DOI: 10.1016/j.ajhg.2016.07.014] [Citation(s) in RCA: 127] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 07/14/2016] [Indexed: 12/13/2022] Open
Abstract
Homozygous loss of SMN1 causes spinal muscular atrophy (SMA), the most common and devastating childhood genetic motor-neuron disease. The copy gene SMN2 produces only ∼10% functional SMN protein, insufficient to counteract development of SMA. In contrast, the human genetic modifier plastin 3 (PLS3), an actin-binding and -bundling protein, fully protects against SMA in SMN1-deleted individuals carrying 3-4 SMN2 copies. Here, we demonstrate that the combinatorial effect of suboptimal SMN antisense oligonucleotide treatment and PLS3 overexpression-a situation resembling the human condition in asymptomatic SMN1-deleted individuals-rescues survival (from 14 to >250 days) and motoric abilities in a severe SMA mouse model. Because PLS3 knockout in yeast impairs endocytosis, we hypothesized that disturbed endocytosis might be a key cellular mechanism underlying impaired neurotransmission and neuromuscular junction maintenance in SMA. Indeed, SMN deficit dramatically reduced endocytosis, which was restored to normal levels by PLS3 overexpression. Upon low-frequency electro-stimulation, endocytotic FM1-43 (SynaptoGreen) uptake in the presynaptic terminal of neuromuscular junctions was restored to control levels in SMA-PLS3 mice. Moreover, proteomics and biochemical analysis revealed CORO1C, another F-actin binding protein, whose direct binding to PLS3 is dependent on calcium. Similar to PLS3 overexpression, CORO1C overexpression restored fluid-phase endocytosis in SMN-knockdown cells by elevating F-actin amounts and rescued the axonal truncation and branching phenotype in Smn-depleted zebrafish. Our findings emphasize the power of genetic modifiers to unravel the cellular pathomechanisms underlying SMA and the power of combinatorial therapy based on splice correction of SMN2 and endocytosis improvement to efficiently treat SMA.
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Tseng YT, Chen CS, Jong YJ, Chang FR, Lo YC. Loganin possesses neuroprotective properties, restores SMN protein and activates protein synthesis positive regulator Akt/mTOR in experimental models of spinal muscular atrophy. Pharmacol Res 2016; 111:58-75. [DOI: 10.1016/j.phrs.2016.05.023] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 05/03/2016] [Accepted: 05/04/2016] [Indexed: 12/21/2022]
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46
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Groen EJN, Gillingwater TH. UBA1: At the Crossroads of Ubiquitin Homeostasis and Neurodegeneration. Trends Mol Med 2016; 21:622-632. [PMID: 26432019 PMCID: PMC4596250 DOI: 10.1016/j.molmed.2015.08.003] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 08/06/2015] [Accepted: 08/10/2015] [Indexed: 12/14/2022]
Abstract
Neurodegenerative diseases are a leading cause of disability and early death. A common feature of these conditions is disruption of protein homeostasis. Ubiquitin-like modifier activating enzyme 1 (UBA1), the E1 ubiquitin-activating enzyme, sits at the apex of the ubiquitin cascade and represents an important regulator of cellular protein homeostasis. Critical contributions of UBA1-dependent pathways to the regulation of homeostasis and degeneration in the nervous system are emerging, including specific disruption of UBA1 in spinal muscular atrophy (SMA) and Huntington's disease (HD). In this review we discuss recent findings that put UBA1 at the centre of cellular homeostasis and neurodegeneration, highlighting the potential for UBA1 to act as a promising therapeutic target for a range of neurodegenerative diseases.
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Affiliation(s)
- Ewout J N Groen
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK; Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK
| | - Thomas H Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK; Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK.
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Somers E, Lees RD, Hoban K, Sleigh JN, Zhou H, Muntoni F, Talbot K, Gillingwater TH, Parson SH. Vascular Defects and Spinal Cord Hypoxia in Spinal Muscular Atrophy. Ann Neurol 2016; 79:217-30. [PMID: 26506088 DOI: 10.1002/ana.24549] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 09/11/2015] [Accepted: 10/18/2015] [Indexed: 01/22/2023]
Abstract
OBJECTIVE Spinal muscular atrophy (SMA) is a major inherited cause of infant death worldwide. It results from mutations in a single, ubiquitously expressed gene (SMN1), with loss of lower motor neurons being the primary pathological signature. Systemic defects have also been reported in SMA patients and animal models. We investigated whether defects associated with the vasculature contribute to motor neuron pathology in SMA. METHODS Development and integrity of the capillary bed was examined in skeletal muscle and spinal cord of SMA mice, and muscle biopsies from SMA patients and controls, using quantitative morphometric approaches on immunohistochemically labeled tissue. Pimonidazole hydrochloride-based assays were used to identify functional hypoxia. RESULTS The capillary bed in muscle and spinal cord was normal in presymptomatic SMA mice (postnatal day 1), but failed to match subsequent postnatal development in control littermates. At mid- and late-symptomatic time points, the extent of the vascular architecture observed in two distinct mouse models of SMA was ∼50% of that observed in control animals. Skeletal muscle biopsies from human patients confirmed the presence of developmentally similar, significant vascular depletion in severe SMA. Hypovascularity in SMA mouse spinal cord was accompanied by significant functional hypoxia and defects in the blood-spinal cord barrier. INTERPRETATION Our results indicate that vascular defects are a major feature of severe forms of SMA, present in both mouse models and patients, resulting in functional hypoxia of motor neurons. Thus, abnormal vascular development and resulting hypoxia may contribute to the pathogenesis of SMA.
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Affiliation(s)
- Eilidh Somers
- Center for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.,Euan MacDonald Center for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Robert D Lees
- Center for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Katie Hoban
- Center for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - James N Sleigh
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Haiyan Zhou
- Dubowitz Neuromuscular Center, Institute of Child Health, University College London, London, United Kingdom
| | - Francesco Muntoni
- Dubowitz Neuromuscular Center, Institute of Child Health, University College London, London, United Kingdom
| | - Kevin Talbot
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Thomas H Gillingwater
- Center for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.,Euan MacDonald Center for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Simon H Parson
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom.,Euan MacDonald Center for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
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Fuller HR, Mandefro B, Shirran SL, Gross AR, Kaus AS, Botting CH, Morris GE, Sareen D. Spinal Muscular Atrophy Patient iPSC-Derived Motor Neurons Have Reduced Expression of Proteins Important in Neuronal Development. Front Cell Neurosci 2016; 9:506. [PMID: 26793058 PMCID: PMC4707261 DOI: 10.3389/fncel.2015.00506] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 12/15/2015] [Indexed: 11/15/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an inherited neuromuscular disease primarily characterized by degeneration of spinal motor neurons, and caused by reduced levels of the SMN protein. Previous studies to understand the proteomic consequences of reduced SMN have mostly utilized patient fibroblasts and animal models. We have derived human motor neurons from type I SMA and healthy controls by creating their induced pluripotent stem cells (iPSCs). Quantitative mass spectrometry of these cells revealed increased expression of 63 proteins in control motor neurons compared to respective fibroblasts, whereas 30 proteins were increased in SMA motor neurons vs. their fibroblasts. Notably, UBA1 was significantly decreased in SMA motor neurons, supporting evidence for ubiquitin pathway defects. Subcellular distribution of UBA1 was predominantly cytoplasmic in SMA motor neurons in contrast to nuclear in control motor neurons; suggestive of neurodevelopmental abnormalities. Many of the proteins that were decreased in SMA motor neurons, including beta III-tubulin and UCHL1, were associated with neurodevelopment and differentiation. These neuron-specific consequences of SMN depletion were not evident in fibroblasts, highlighting the importance of iPSC technology. The proteomic profiles identified here provide a useful resource to explore the molecular consequences of reduced SMN in motor neurons, and for the identification of novel biomarker and therapeutic targets for SMA.
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Affiliation(s)
- Heidi R Fuller
- Wolfson Centre for Inherited Neuromuscular Disease, The Robert Jones and Agnes Hunt Orthopaedic HospitalOswestry, UK; Institute for Science and Technology in Medicine, Keele UniversityStaffordshire, UK
| | - Berhan Mandefro
- Board of Governors-Regenerative Medicine Institute, Cedars-Sinai Medical CenterLos Angeles, CA, USA; iPSC Core, The David and Janet Polak Foundation Stem Cell Core LaboratoryLos Angeles, CA, USA
| | - Sally L Shirran
- BSRC Mass Spectrometry and Proteomics Facility, University of St Andrews Fife, UK
| | - Andrew R Gross
- Board of Governors-Regenerative Medicine Institute, Cedars-Sinai Medical Center Los Angeles, CA, USA
| | - Anjoscha S Kaus
- Board of Governors-Regenerative Medicine Institute, Cedars-Sinai Medical Center Los Angeles, CA, USA
| | - Catherine H Botting
- BSRC Mass Spectrometry and Proteomics Facility, University of St Andrews Fife, UK
| | - Glenn E Morris
- Wolfson Centre for Inherited Neuromuscular Disease, The Robert Jones and Agnes Hunt Orthopaedic HospitalOswestry, UK; Institute for Science and Technology in Medicine, Keele UniversityStaffordshire, UK
| | - Dhruv Sareen
- Board of Governors-Regenerative Medicine Institute, Cedars-Sinai Medical CenterLos Angeles, CA, USA; iPSC Core, The David and Janet Polak Foundation Stem Cell Core LaboratoryLos Angeles, CA, USA; Department of Biomedical Sciences, Cedars-Sinai Medical CenterLos Angeles, CA, USA
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Neuroplasticity and Repair in Rodent Neurotoxic Models of Spinal Motoneuron Disease. Neural Plast 2016; 2016:2769735. [PMID: 26862439 PMCID: PMC4735933 DOI: 10.1155/2016/2769735] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 07/12/2015] [Accepted: 08/19/2015] [Indexed: 12/14/2022] Open
Abstract
Retrogradely transported toxins are widely used to set up protocols for selective lesioning of the nervous system. These methods could be collectively named "molecular neurosurgery" because they are able to destroy specific types of neurons by using targeted neurotoxins. Lectins such as ricin, volkensin, or modeccin and neuropeptide- or antibody-conjugated saporin represent the most effective toxins used for neuronal lesioning. Some of these specific neurotoxins could be used to induce selective depletion of spinal motoneurons. In this review, we extensively describe two rodent models of motoneuron degeneration induced by volkensin or cholera toxin-B saporin. In particular, we focus on the possible experimental use of these models to mimic neurodegenerative diseases, to dissect the molecular mechanisms of neuroplastic changes underlying the spontaneous functional recovery after motoneuron death, and finally to test different strategies of neural repair. The potential clinical applications of these approaches are also discussed.
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50
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Cerveró C, Montull N, Tarabal O, Piedrafita L, Esquerda JE, Calderó J. Chronic Treatment with the AMPK Agonist AICAR Prevents Skeletal Muscle Pathology but Fails to Improve Clinical Outcome in a Mouse Model of Severe Spinal Muscular Atrophy. Neurotherapeutics 2016; 13:198-216. [PMID: 26582176 PMCID: PMC4720671 DOI: 10.1007/s13311-015-0399-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a genetic neuromuscular disorder characterized by spinal and brainstem motor neuron (MN) loss and skeletal muscle paralysis. Currently, there is no effective treatment other than supportive care to ameliorate the quality of life of patients with SMA. Some studies have reported that physical exercise, by improving muscle strength and motor function, is potentially beneficial in SMA. The adenosine monophosphate-activated protein kinase agonist 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) has been reported to be an exercise mimetic agent that is able to regulate muscle metabolism and increase endurance both at rest and during exercise. Chronic AICAR administration has been shown to ameliorate the dystrophic muscle phenotype and motor behavior in the mdx mouse, a model of Duchenne muscular dystrophy. Here, we investigated whether chronic AICAR treatment was able to elicit beneficial effects on motor abilities and neuromuscular histopathology in a mouse model of severe SMA (the SMNΔ7 mouse). We report that AICAR improved skeletal muscle atrophy and structural changes found in neuromuscular junctions of SMNΔ7 animals. However, although AICAR prevented the loss of glutamatergic excitatory synapses on MNs, this compound was not able to mitigate MN loss or the microglial and astroglial reaction occurring in the spinal cord of diseased mice. Moreover, no improvement in survival or motor performance was seen in SMNΔ7 animals treated with AICAR. The beneficial effects of AICAR in SMA found in our study are SMN-independent, as no changes in the expression of this protein were seen in the spinal cord and skeletal muscle of diseased animals treated with this compound.
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Affiliation(s)
- Clàudia Cerveró
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Av. Rovira Roure 80, 25198, Lleida, Catalonia, Spain
| | - Neus Montull
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Av. Rovira Roure 80, 25198, Lleida, Catalonia, Spain
| | - Olga Tarabal
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Av. Rovira Roure 80, 25198, Lleida, Catalonia, Spain
| | - Lídia Piedrafita
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Av. Rovira Roure 80, 25198, Lleida, Catalonia, Spain
| | - Josep E Esquerda
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Av. Rovira Roure 80, 25198, Lleida, Catalonia, Spain
| | - Jordi Calderó
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLLEIDA), Av. Rovira Roure 80, 25198, Lleida, Catalonia, Spain.
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