1
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Gonzalez D, Vásquez-Doorman C, Luna A, Allende ML. Modeling Spinal Muscular Atrophy in Zebrafish: Current Advances and Future Perspectives. Int J Mol Sci 2024; 25:1962. [PMID: 38396640 PMCID: PMC10888324 DOI: 10.3390/ijms25041962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 12/20/2023] [Accepted: 12/29/2023] [Indexed: 02/25/2024] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disease characterized by degeneration of lower motor neurons (LMNs), causing muscle weakness, atrophy, and paralysis. SMA is caused by mutations in the Survival Motor Neuron 1 (SMN1) gene and can be classified into four subgroups, depending on its severity. Even though the genetic component of SMA is well known, the precise mechanisms underlying its pathophysiology remain elusive. Thus far, there are three FDA-approved drugs for treating SMA. While these treatments have shown promising results, their costs are extremely high and unaffordable for most patients. Thus, more efforts are needed in order to identify novel therapeutic targets. In this context, zebrafish (Danio rerio) stands out as an ideal animal model for investigating neurodegenerative diseases like SMA. Its well-defined motor neuron circuits and straightforward neuromuscular structure offer distinct advantages. The zebrafish's suitability arises from its low-cost genetic manipulation and optical transparency exhibited during larval stages, which facilitates in vivo microscopy. This review explores advancements in SMA research over the past two decades, beginning with the creation of the first zebrafish model. Our review focuses on the findings using different SMA zebrafish models generated to date, including potential therapeutic targets such as U snRNPs, Etv5b, PLS3, CORO1C, Pgrn, Cpg15, Uba1, Necdin, and Pgk1, among others. Lastly, we conclude our review by emphasizing the future perspectives in the field, namely exploiting zebrafish capacity for high-throughput screening. Zebrafish, with its unique attributes, proves to be an ideal model for studying motor neuron diseases and unraveling the complexity of neuromuscular defects.
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Affiliation(s)
- David Gonzalez
- Millennium Institute Center for Genome Regulation, Facultad de Ciencias, Universidad de Chile, Santiago 7800003, RM, Chile
- Departamento de Ciencias Químicas y Biológicas, Facultad de Ciencias de la Salud, Universidad Bernardo O'Higgins, Santiago 8370854, RM, Chile
| | - Constanza Vásquez-Doorman
- Millennium Institute Center for Genome Regulation, Facultad de Ciencias, Universidad de Chile, Santiago 7800003, RM, Chile
- Departamento de Ciencias Químicas y Biológicas, Facultad de Ciencias de la Salud, Universidad Bernardo O'Higgins, Santiago 8370854, RM, Chile
| | - Adolfo Luna
- Departamento de Ciencias Químicas y Biológicas, Facultad de Ciencias de la Salud, Universidad Bernardo O'Higgins, Santiago 8370854, RM, Chile
| | - Miguel L Allende
- Millennium Institute Center for Genome Regulation, Facultad de Ciencias, Universidad de Chile, Santiago 7800003, RM, Chile
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2
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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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3
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Nikolaou N, Gordon PM, Hamid F, Taylor R, Lloyd-Jones J, Makeyev EV, Houart C. Cytoplasmic pool of U1 spliceosome protein SNRNP70 shapes the axonal transcriptome and regulates motor connectivity. Curr Biol 2022; 32:5099-5115.e8. [PMID: 36384140 DOI: 10.1016/j.cub.2022.10.048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 09/09/2022] [Accepted: 10/21/2022] [Indexed: 11/17/2022]
Abstract
Regulation of pre-mRNA splicing and polyadenylation plays a profound role in neurons by diversifying the proteome and modulating gene expression in response to physiological cues. Although most of the pre-mRNA processing is thought to occur in the nucleus, numerous splicing regulators are also found in neurites. Here, we show that U1-70K/SNRNP70, a component of the major spliceosome, localizes in RNA-associated granules in zebrafish axons. We identify the extra-nuclear SNRNP70 as an important regulator of motor axonal growth, nerve-dependent acetylcholine receptor (AChR) clustering, and neuromuscular synaptogenesis. This cytoplasmic pool has a protective role for a limited number of transcripts regulating their abundance and trafficking inside axons. Moreover, non-nuclear SNRNP70 regulates splice variants of transcripts such as agrin, thereby controlling synapse formation. Our results point to an unexpected, yet essential, function of non-nuclear SNRNP70 in axonal development, indicating a role of spliceosome proteins in cytoplasmic RNA metabolism during neuronal connectivity.
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Affiliation(s)
- Nikolas Nikolaou
- Centre for Developmental Neurobiology MRC CNDD, IoPPN, Guy's Campus, King's College London, London SE1 1UL, UK; Department of Life Sciences, University of Bath, Bath BA2 7AY, UK.
| | - Patricia M Gordon
- Centre for Developmental Neurobiology MRC CNDD, IoPPN, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Fursham Hamid
- Centre for Developmental Neurobiology MRC CNDD, IoPPN, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Richard Taylor
- Centre for Developmental Neurobiology MRC CNDD, IoPPN, Guy's Campus, King's College London, London SE1 1UL, UK
| | | | - Eugene V Makeyev
- Centre for Developmental Neurobiology MRC CNDD, IoPPN, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Corinne Houart
- Centre for Developmental Neurobiology MRC CNDD, IoPPN, Guy's Campus, King's College London, London SE1 1UL, UK.
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4
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Lescouzères L, Bordignon B, Bomont P. Development of a high-throughput tailored imaging method in zebrafish to understand and treat neuromuscular diseases. Front Mol Neurosci 2022; 15:956582. [PMID: 36204134 PMCID: PMC9530744 DOI: 10.3389/fnmol.2022.956582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 08/16/2022] [Indexed: 11/13/2022] Open
Abstract
The zebrafish (Danio rerio) is a vertebrate species offering multitude of advantages for the study of conserved biological systems in human and has considerably enriched our knowledge in developmental biology and physiology. Being equally important in medical research, the zebrafish has become a critical tool in the fields of diagnosis, gene discovery, disease modeling, and pharmacology-based therapy. Studies on the zebrafish neuromuscular system allowed for deciphering key molecular pathways in this tissue, and established it as a model of choice to study numerous motor neurons, neuromuscular junctions, and muscle diseases. Starting with the similarities of the zebrafish neuromuscular system with the human system, we review disease models associated with the neuromuscular system to focus on current methodologies employed to study them and outline their caveats. In particular, we put in perspective the necessity to develop standardized and high-resolution methodologies that are necessary to deepen our understanding of not only fundamental signaling pathways in a healthy tissue but also the changes leading to disease phenotype outbreaks, and offer templates for high-content screening strategies. While the development of high-throughput methodologies is underway for motility assays, there is no automated approach to quantify the key molecular cues of the neuromuscular junction. Here, we provide a novel high-throughput imaging methodology in the zebrafish that is standardized, highly resolutive, quantitative, and fit for drug screening. By providing a proof of concept for its robustness in identifying novel molecular players and therapeutic drugs in giant axonal neuropathy (GAN) disease, we foresee that this new tool could be useful for both fundamental and biomedical research.
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Affiliation(s)
- Léa Lescouzères
- ERC Team, Institut NeuroMyoGéne-PGNM, Inserm U1315, CNRS UMR 5261, Claude Bernard University Lyon 1, Lyon, France
| | - Benoît Bordignon
- Montpellier Ressources Imagerie, BioCampus, CNRS, INSERM, University of Montpellier, Montpellier, France
| | - Pascale Bomont
- ERC Team, Institut NeuroMyoGéne-PGNM, Inserm U1315, CNRS UMR 5261, Claude Bernard University Lyon 1, Lyon, France
- *Correspondence: Pascale Bomont,
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5
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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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6
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Casey MA, Hill JT, Hoshijima K, Bryan CD, Gribble SL, Brown JT, Chien CB, Yost HJ, Kwan KM. Shutdown corner, a large deletion mutant isolated from a haploid mutagenesis screen in zebrafish. G3 (BETHESDA, MD.) 2022; 12:jkab442. [PMID: 35079792 PMCID: PMC9210284 DOI: 10.1093/g3journal/jkab442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 12/15/2021] [Indexed: 11/13/2022]
Abstract
Morphogenesis, the formation of three-dimensional organ structures, requires precise coupling of genetic regulation and complex cell behaviors. The genetic networks governing many morphogenetic systems, including that of the embryonic eye, are poorly understood. In zebrafish, several forward genetic screens have sought to identify factors regulating eye development. These screens often look for eye defects at stages after the optic cup is formed and when retinal neurogenesis is under way. This approach can make it difficult to identify mutants specific for morphogenesis, as opposed to neurogenesis. To this end, we carried out a forward genetic, small-scale haploid mutagenesis screen in zebrafish (Danio rerio) to identify factors that govern optic cup morphogenesis. We screened ∼100 genomes and isolated shutdown corner (sco), a mutant that exhibits multiple tissue defects and harbors a ∼10-Mb deletion that encompasses 89 annotated genes. Using a combination of live imaging and antibody staining, we found cell proliferation, cell death, and tissue patterning defects in the sco optic cup. We also observed other phenotypes, including paralysis, neuromuscular defects, and ocular vasculature defects. To date, the largest deletion mutants reported in zebrafish are engineered using CRISPR-Cas9 and are less than 300 kb. Because of the number of genes within the deletion interval, shutdown corner [Df(Chr05:sco)z207] could be a useful resource to the zebrafish community, as it may be helpful for gene mapping, understanding genetic interactions, or studying many genes lost in the mutant.
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Affiliation(s)
- Macaulie A Casey
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Jonathon T Hill
- Department of Cell Biology and Physiology, Brigham Young University, Provo, UT 84602, USA
| | - Kazuyuki Hoshijima
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Chase D Bryan
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL 32611, USA
| | - Suzanna L Gribble
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - J Thomas Brown
- Department of Biomedical Informatics, Vanderbilt University, Nashville, TN 37203, USA
| | - Chi-Bin Chien
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84112, USA
| | - H Joseph Yost
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84112, USA
| | - Kristen M Kwan
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
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7
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Butchbach MER. Genomic Variability in the Survival Motor Neuron Genes ( SMN1 and SMN2): Implications for Spinal Muscular Atrophy Phenotype and Therapeutics Development. Int J Mol Sci 2021; 22:ijms22157896. [PMID: 34360669 PMCID: PMC8348669 DOI: 10.3390/ijms22157896] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 07/14/2021] [Accepted: 07/21/2021] [Indexed: 02/07/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a leading genetic cause of infant death worldwide that is characterized by loss of spinal motor neurons leading to muscle weakness and atrophy. SMA results from the loss of survival motor neuron 1 (SMN1) gene but retention of its paralog SMN2. The copy numbers of SMN1 and SMN2 are variable within the human population with SMN2 copy number inversely correlating with SMA severity. Current therapeutic options for SMA focus on increasing SMN2 expression and alternative splicing so as to increase the amount of SMN protein. Recent work has demonstrated that not all SMN2, or SMN1, genes are equivalent and there is a high degree of genomic heterogeneity with respect to the SMN genes. Because SMA is now an actionable disease with SMN2 being the primary target, it is imperative to have a comprehensive understanding of this genomic heterogeneity with respect to hybrid SMN1–SMN2 genes generated by gene conversion events as well as partial deletions of the SMN genes. This review will describe this genetic heterogeneity in SMA and its impact on disease phenotype as well as therapeutic efficacy.
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Affiliation(s)
- Matthew E. R. Butchbach
- Center for Applied Clinical Genomics, Nemours Children’s Health Delaware, Wilmington, DE 19803, USA;
- Center for Pediatric Research, Nemours Children’s Health Delaware, Wilmington, DE 19803, USA
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
- Department of Pediatrics, Thomas Jefferson University, Philadelphia, PA 19107, USA
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8
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Tay SH, Ellieyana EN, Le Y, Sarusie MV, Grimm C, Ohmer J, Mathuru A, Fischer U, Winkler C. A novel zebrafish model for intermediate type spinal muscular atrophy demonstrates importance of Smn for maintenance of mature motor neurons. Hum Mol Genet 2021; 30:2488-2502. [PMID: 34302176 DOI: 10.1093/hmg/ddab212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 07/09/2021] [Accepted: 07/19/2021] [Indexed: 11/13/2022] Open
Abstract
A deficiency in Survival Motor Neuron (SMN) protein results in motor neuron loss in spinal muscular atrophy (SMA) patients. Human SMN is encoded by SMN1 and SMN2 that differ by a single C6T transition in a splice regulatory region of exon 7. In SMN2, exon 7 is skipped leading to an unstable protein, which cannot compensate for SMN1 loss in SMA patients. The disease severity of human SMA (Types 1 to 4) depends on the levels of SMN protein, with intermediate levels leading to delayed disease onset and extended life expectancy in Type 2 patients. We used homology directed repair (HDR) to generate a zebrafish mutant with intermediate Smn levels, to mimic intermediate, hSMN2 dependent forms of SMA. In the obtained smnA6Tind27 mutant zebrafish, Smn protein formed oligomers but protein levels dropped significantly at juvenile stages. Motor neurons and neuromuscular junctions (NMJ) also formed normally initially but motor neuron loss and locomotor deficiencies became evident at 21 days. Subsequent muscle wasting and early adult lethality also phenocopied intermediate forms of human SMA. Together, our findings are consistent with the interpretation that Smn is required for neuromuscular maintenance, and establish the smnA6Tind27 zebrafish mutant as a novel model for intermediate types of SMA. As this mutant allows studying the effect of late Smn loss on motor neurons, neuromuscular junctions, and muscle at advanced stages of the disease, it will be a valuable resource for testing new drugs targeted towards treating intermediate forms of SMA.
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Affiliation(s)
- Shermaine Huiping Tay
- Department of Biological Sciences and Centre for Bioimaging Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Erna Nur Ellieyana
- Department of Biological Sciences and Centre for Bioimaging Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Yao Le
- Department of Biological Sciences and Centre for Bioimaging Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Menachem Viktor Sarusie
- Department of Biological Sciences and Centre for Bioimaging Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Clemens Grimm
- Department of Biochemistry, Biocenter, University of Wuerzburg, 97074 Wuerzburg, Germany
| | - Jürgen Ohmer
- Department of Biochemistry, Biocenter, University of Wuerzburg, 97074 Wuerzburg, Germany
| | - Ajay Mathuru
- Yale-NUS College, 12 College Avenue West, Singapore 138527, Singapore.,Institute of Molecular and Cell Biology, Singapore 138673, Singapore.,Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Utz Fischer
- Department of Biochemistry, Biocenter, University of Wuerzburg, 97074 Wuerzburg, Germany
| | - Christoph Winkler
- Department of Biological Sciences and Centre for Bioimaging Sciences, National University of Singapore, Singapore 117543, Singapore
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9
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Li X, Gao Y, Tian F, Du R, Yuan Y, Li P, Liu F, Wang C. miR-31 promotes neural stem cell proliferation and restores motor function after spinal cord injury. Exp Biol Med (Maywood) 2021; 246:1274-1286. [PMID: 33715531 PMCID: PMC8371310 DOI: 10.1177/1535370221997071] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 02/01/2021] [Indexed: 01/17/2023] Open
Abstract
This study aims to examine whether miR-31 promotes endogenous NSC proliferation and be used for spinal cord injury management. In the present study, the morpholino knockdown of miR-31 induced abnormal neuronal apoptosis in zebrafish, resulting in impaired development of the tail. miR-31 agomir transfection in NSCs increased Nestin expression and decreased ChAT and GFAP expression levels. miR-31 induced the proliferation of mouse NSCs by upregulating the Notch signaling pathway, and more NSCs entered G1; Notch was inhibited by miR-31 inactivation. Injection of a miR-31 agomir into mouse models of spinal cord injury could effectively restore motor functions after spinal cord injury, which was achieved by promoting the proliferation of endogenous NSCs. After the injection of a miR-31 agomir in spinal cord injury mice, the expression of Nestin and GFAP increased, while GFAP expression decreased. In conclusion, the zebrafish experiments prove that a lack of miR-31 will block nervous system development. In spinal cord injury mouse models, miR-31 overexpression might promote spinal cord injury repair.
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Affiliation(s)
- Xiao Li
- Laboratory Animal Research Center of Shanxi Medical University, Shanxi Key Laboratory of Animal and Animal Model of Human Diseases, Taiyuan 030001, China
| | - Yuantao Gao
- Queen Mary School, Nanchang University, Nanchang 330000, China
| | - Feng Tian
- Laboratory Animal Research Center of Shanxi Medical University, Shanxi Key Laboratory of Animal and Animal Model of Human Diseases, Taiyuan 030001, China
| | - Ruochen Du
- Laboratory Animal Research Center of Shanxi Medical University, Shanxi Key Laboratory of Animal and Animal Model of Human Diseases, Taiyuan 030001, China
| | - Yitong Yuan
- Laboratory Animal Research Center of Shanxi Medical University, Shanxi Key Laboratory of Animal and Animal Model of Human Diseases, Taiyuan 030001, China
| | - Pengfei Li
- Laboratory Animal Research Center of Shanxi Medical University, Shanxi Key Laboratory of Animal and Animal Model of Human Diseases, Taiyuan 030001, China
| | - Fang Liu
- Laboratory Animal Research Center of Shanxi Medical University, Shanxi Key Laboratory of Animal and Animal Model of Human Diseases, Taiyuan 030001, China
| | - Chunfang Wang
- Laboratory Animal Research Center of Shanxi Medical University, Shanxi Key Laboratory of Animal and Animal Model of Human Diseases, Taiyuan 030001, China
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10
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Koh A, Tao S, Jing Goh Y, Chaganty V, See K, Purushothaman K, Orbán L, Mathuru AS, Wohland T, Winkler C. A Neurexin2aa deficiency results in axon pathfinding defects and increased anxiety in zebrafish. Hum Mol Genet 2020; 29:3765-3780. [PMID: 33276371 DOI: 10.1093/hmg/ddaa260] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 11/04/2020] [Accepted: 11/30/2020] [Indexed: 12/17/2022] Open
Abstract
Neurexins are presynaptic transmembrane proteins that control synapse activity and are risk factors for autism spectrum disorder. Zebrafish, a popular model for behavioral studies, has six neurexin genes, but their functions in embryogenesis and behavior remain largely unknown. We have previously reported that nrxn2a is aberrantly spliced and specifically dysregulated in motor neurons (MNs) in models of spinal muscular atrophy. In this study, we generated nrxn2aa-/- mutants by CRISPR/Cas9 to understand nrxn2aa function at the zebrafish neuromuscular junction (NMJ) and to determine the effects of its deficiency on adult behavior. Homozygous mutant embryos derived from heterozygous parents did not show obvious defects in axon outgrowth or synaptogenesis of MNs. In contrast, maternal-zygotic (MZ) nrxn2aa-/- mutants displayed extensively branched axons and defective MNs, suggesting a cell-autonomous role for maternally provided nrxn2aa in MN development. Analysis of the NMJs revealed enlarged choice points in MNs of mutant larvae and reduced co-localization of pre- and post-synaptic terminals, indicating impaired synapse formation. Severe early NMJ defects partially recovered in late embryos when mutant transcripts became strongly upregulated. Ultimately, however, the induced defects resulted in muscular atrophy symptoms in adult MZ mutants. Zygotic homozygous mutants developed normally but displayed increased anxiety at adult stages. Together, our data demonstrate an essential role for maternal nrxn2aa in NMJ synapse establishment, while zygotic nrxn2aa expression appears dispensable for synapse maintenance. The viable nrxn2aa-/- mutant furthermore serves as a novel model to study how an increase in anxiety-like behaviors impacts other deficits.
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Affiliation(s)
- Angela Koh
- Department of Biological Sciences and Centre for Bioimaging Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Shijie Tao
- Department of Biological Sciences and Centre for Bioimaging Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Yun Jing Goh
- Department of Biological Sciences and Centre for Bioimaging Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Vindhya Chaganty
- Department of Biological Sciences and Centre for Bioimaging Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Kelvin See
- Department of Biological Sciences and Centre for Bioimaging Sciences, National University of Singapore, Singapore 117543, Singapore
| | | | - László Orbán
- Reproductive Genomics Group, Temasek Life Sciences Laboratory, Singapore 117604, Singapore
| | - Ajay S Mathuru
- Yale-NUS College, Singapore 138527, Singapore.,Institute of Molecular and Cell Biology, Singapore 138673, Singapore
| | - Thorsten Wohland
- Department of Biological Sciences and Centre for Bioimaging Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Christoph Winkler
- Department of Biological Sciences and Centre for Bioimaging Sciences, National University of Singapore, Singapore 117543, Singapore
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11
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Menduti G, Rasà DM, Stanga S, Boido M. Drug Screening and Drug Repositioning as Promising Therapeutic Approaches for Spinal Muscular Atrophy Treatment. Front Pharmacol 2020; 11:592234. [PMID: 33281605 PMCID: PMC7689316 DOI: 10.3389/fphar.2020.592234] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 09/29/2020] [Indexed: 12/12/2022] Open
Abstract
Spinal muscular atrophy (SMA) is the most common genetic disease affecting infants and young adults. Due to mutation/deletion of the survival motor neuron (SMN) gene, SMA is characterized by the SMN protein lack, resulting in motor neuron impairment, skeletal muscle atrophy and premature death. Even if the genetic causes of SMA are well known, many aspects of its pathogenesis remain unclear and only three drugs have been recently approved by the Food and Drug Administration (Nusinersen-Spinraza; Onasemnogene abeparvovec or AVXS-101-Zolgensma; Risdiplam-Evrysdi): although assuring remarkable results, the therapies show some important limits including high costs, still unknown long-term effects, side effects and disregarding of SMN-independent targets. Therefore, the research of new therapeutic strategies is still a hot topic in the SMA field and many efforts are spent in drug discovery. In this review, we describe two promising strategies to select effective molecules: drug screening (DS) and drug repositioning (DR). By using compounds libraries of chemical/natural compounds and/or Food and Drug Administration-approved substances, DS aims at identifying new potentially effective compounds, whereas DR at testing drugs originally designed for the treatment of other pathologies. The drastic reduction in risks, costs and time expenditure assured by these strategies make them particularly interesting, especially for those diseases for which the canonical drug discovery process would be long and expensive. Interestingly, among the identified molecules by DS/DR in the context of SMA, besides the modulators of SMN2 transcription, we highlighted a convergence of some targeted molecular cascades contributing to SMA pathology, including cell death related-pathways, mitochondria and cytoskeleton dynamics, neurotransmitter and hormone modulation.
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Affiliation(s)
| | | | | | - Marina Boido
- Department of Neuroscience Rita Levi Montalcini, Neuroscience Institute Cavalieri Ottolenghi, University of Turin, Turin, Italy
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12
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Oprişoreanu AM, Smith HL, Arya S, Webster R, Zhong Z, Eaton-Hart C, Wehner D, Cardozo MJ, Becker T, Talbot K, Becker CG. Interaction of Axonal Chondrolectin with Collagen XIXa1 Is Necessary for Precise Neuromuscular Junction Formation. Cell Rep 2020; 29:1082-1098.e10. [PMID: 31665626 DOI: 10.1016/j.celrep.2019.09.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 08/13/2019] [Accepted: 09/12/2019] [Indexed: 01/05/2023] Open
Abstract
Chondrolectin (Chodl) is needed for motor axon extension in zebrafish and is dysregulated in mouse models of spinal muscular atrophy (SMA). However, the mechanistic basis of Chodl function is not known. Here, we use Chodl-deficient zebrafish and mouse mutants to show that the absence of Chodl leads to anatomical and functional defects of the neuromuscular synapse. In zebrafish, the growth of an identified motor axon beyond an "en passant" synapse and later axon branching from synaptic points are impaired, leading to functional deficits. Mechanistically, motor-neuron-autonomous Chodl function depends on its intracellular domain and on binding muscle-derived collagen XIXa1 by its extracellular C-type lectin domain. Our data support evolutionarily conserved roles of Chodl in synaptogenesis and provide evidence for a "synapse-first" scenario of motor axon growth in zebrafish.
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Affiliation(s)
- Ana-Maria Oprişoreanu
- Centre for Discovery Brain Sciences, University of Edinburgh, The Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Hannah L Smith
- Centre for Discovery Brain Sciences, University of Edinburgh, The Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Sukrat Arya
- Nuffield Department of Clinical Neurosciences, West Wing, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, UK
| | - Richard Webster
- Nuffield Department of Clinical Neurosciences, West Wing, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, UK
| | - Zhen Zhong
- Centre for Discovery Brain Sciences, University of Edinburgh, The Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Charlotte Eaton-Hart
- Nuffield Department of Clinical Neurosciences, West Wing, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, UK
| | - Daniel Wehner
- Centre for Discovery Brain Sciences, University of Edinburgh, The Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Marcos J Cardozo
- Centre for Discovery Brain Sciences, University of Edinburgh, The Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Thomas Becker
- Centre for Discovery Brain Sciences, University of Edinburgh, The Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB, UK; Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK.
| | - Kevin Talbot
- Nuffield Department of Clinical Neurosciences, West Wing, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, UK.
| | - Catherina G Becker
- Centre for Discovery Brain Sciences, University of Edinburgh, The Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB, UK; Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK.
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13
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Stout KA, Dunn AR, Hoffman C, Miller GW. The Synaptic Vesicle Glycoprotein 2: Structure, Function, and Disease Relevance. ACS Chem Neurosci 2019; 10:3927-3938. [PMID: 31394034 DOI: 10.1021/acschemneuro.9b00351] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The synaptic vesicle glycoprotein 2 (SV2) family is comprised of three paralogues: SV2A, SV2B, and SV2C. In vertebrates, SV2s are 12-transmembrane proteins present on every secretory vesicle, including synaptic vesicles, and are critical to neurotransmission. Structural and functional studies suggest that SV2 proteins may play several roles to promote proper vesicular function. Among these roles are their potential to stabilize the transmitter content of vesicles, to maintain and orient the releasable pool of vesicles, and to regulate vesicular calcium sensitivity to ensure efficient, coordinated release of the transmitter. The SV2 family is highly relevant to human health in a number of ways. First, SV2A plays a role in neuronal excitability and as such is the specific target for the antiepileptic drug levetiracetam. SV2 proteins also act as the target by which potent neurotoxins, particularly botulinum, gain access to neurons and exert their toxicity. Both SV2B and SV2C are increasingly implicated in diseases such as Alzheimer's disease and Parkinson's disease. Interestingly, despite decades of intensive research, their exact function remains elusive. Thus, SV2 proteins are intriguing in their potentially diverse roles within the presynaptic terminal, and several recent developments have enhanced our understanding and appreciation of the protein family. Here, we review the structure and function of SV2 proteins as well as their relevance to disease and therapeutic development.
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Affiliation(s)
- Kristen A Stout
- Department of Physiology , Northwestern University, Feinberg School of Medicine , Chicago , Illinois , United States
| | - Amy R Dunn
- The Jackson Laboratory , Bar Harbor , Maine , United States
| | - Carlie Hoffman
- Department of Environmental Health, Rollins School of Public Health , Emory University , Atlanta , Georgia , United States
| | - Gary W Miller
- Department of Environmental Health Sciences, Mailman School of Public Health , Columbia University , New York , New York , United States
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14
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Modulation of Agrin and RhoA Pathways Ameliorates Movement Defects and Synapse Morphology in MYO9A-Depleted Zebrafish. Cells 2019; 8:cells8080848. [PMID: 31394789 PMCID: PMC6721702 DOI: 10.3390/cells8080848] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 07/24/2019] [Accepted: 08/02/2019] [Indexed: 12/14/2022] Open
Abstract
Congenital myasthenic syndromes (CMS) are a group of rare, inherited disorders characterised by impaired function of the neuromuscular junction (NMJ). This is due to defects in one of the many proteins associated with the NMJ. In three patients with CMS, missense mutations in a gene encoding an unconventional myosin protein, MYO9A, were identified as likely causing their disorder. Preliminary studies revealed a potential involvement of the RhoA/ROCK pathway and of a key NMJ protein, agrin, in the pathophysiology of MYO9A-depletion. In this study, a CRISPR/Cas9 approach was used to generate genetic mutants of MYO9A zebrafish orthologues, myo9aa/ab, to expand and refine the morphological analysis of the NMJ. Injection of NT1654, a synthetic agrin fragment compound, improved NMJ structure and zebrafish movement in the absence of Myo9aa/ab. In addition, treatment of zebrafish with fasudil, a ROCK inhibitor, also provided improvements to the morphology of NMJs in early development, as well as rescuing movement defects, but not to the same extent as NT1654 and not at later time points. Therefore, this study highlights a role for MYO9A at the NMJ, the first unconventional myosin motor protein associated with a neuromuscular disease, and provides a potential mechanism of action of MYO9A-pathophysiology.
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15
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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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16
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Osman EY, Bolding MR, Villalón E, Kaifer KA, Lorson ZC, Tisdale S, Hao Y, Conant GC, Pires JC, Pellizzoni L, Lorson CL. Functional characterization of SMN evolution in mouse models of SMA. Sci Rep 2019; 9:9472. [PMID: 31263170 PMCID: PMC6603021 DOI: 10.1038/s41598-019-45822-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 06/11/2019] [Indexed: 12/13/2022] Open
Abstract
Spinal Muscular Atrophy (SMA) is a monogenic neurodegenerative disorder and the leading genetic cause of infantile mortality. While several functions have been ascribed to the SMN (survival motor neuron) protein, their specific contribution to the disease has yet to be fully elucidated. We hypothesized that some, but not all, SMN homologues would rescue the SMA phenotype in mouse models, thereby identifying disease-relevant domains. Using AAV9 to deliver Smn homologs to SMA mice, we identified a conservation threshold that marks the boundary at which homologs can rescue the SMA phenotype. Smn from Danio rerio and Xenopus laevis significantly prevent disease, whereas Smn from Drosophila melanogaster, Caenorhabditis elegans, and Schizosaccharomyces pombe was significantly less efficacious. This phenotypic rescue correlated with correction of RNA processing defects induced by SMN deficiency and neuromuscular junction pathology. Based upon the sequence conservation in the rescuing homologs, a minimal SMN construct was designed consisting of exons 2, 3, and 6, which showed a partial rescue of the SMA phenotype. While a significant extension in survival was observed, the absence of a complete rescue suggests that while the core conserved region is essential, additional sequences contribute to the overall ability of the SMN protein to rescue disease pathology.
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Affiliation(s)
- Erkan Y Osman
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, 65211, USA.,Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA
| | - Madeline R Bolding
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, 65211, USA.,Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA
| | - Eric Villalón
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, 65211, USA.,Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA
| | - Kevin A Kaifer
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, 65211, USA.,Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA
| | - Zachary C Lorson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, 65211, USA.,Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA
| | - Sarah Tisdale
- Center for Motor Neuron Biology and Disease, Department of Pathology and Cell Biology, Columbia University, New York, NY, 10032, USA
| | - Yue Hao
- Bioinformatics Research Center, North Carolina State University, Raleigh, NC, 27695, USA
| | - Gavin C Conant
- Bioinformatics Research Center, North Carolina State University, Raleigh, NC, 27695, USA.,Division of Animal Sciences, University of Missouri, Columbia, MO, 65211, USA.,Division of Biological Sciences, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA
| | - J Chris Pires
- Department of Biological Sciences, Program in Genetics, North Carolina State University, Raleigh, NC, 27695, USA
| | - Livio Pellizzoni
- Center for Motor Neuron Biology and Disease, Department of Pathology and Cell Biology, Columbia University, New York, NY, 10032, USA
| | - Christian L Lorson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, 65211, USA. .,Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA.
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17
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Guided genetic screen to identify genes essential in the regeneration of hair cells and other tissues. NPJ Regen Med 2018; 3:11. [PMID: 29872546 PMCID: PMC5986822 DOI: 10.1038/s41536-018-0050-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 04/18/2018] [Accepted: 05/08/2018] [Indexed: 02/06/2023] Open
Abstract
Regenerative medicine holds great promise for both degenerative diseases and traumatic tissue injury which represent significant challenges to the health care system. Hearing loss, which affects hundreds of millions of people worldwide, is caused primarily by a permanent loss of the mechanosensory receptors of the inner ear known as hair cells. This failure to regenerate hair cells after loss is limited to mammals, while all other non-mammalian vertebrates tested were able to completely regenerate these mechanosensory receptors after injury. To understand the mechanism of hair cell regeneration and its association with regeneration of other tissues, we performed a guided mutagenesis screen using zebrafish lateral line hair cells as a screening platform to identify genes that are essential for hair cell regeneration, and further investigated how genes essential for hair cell regeneration were involved in the regeneration of other tissues. We created genetic mutations either by retroviral insertion or CRISPR/Cas9 approaches, and developed a high-throughput screening pipeline for analyzing hair cell development and regeneration. We screened 254 gene mutations and identified 7 genes specifically affecting hair cell regeneration. These hair cell regeneration genes fell into distinct and somewhat surprising functional categories. By examining the regeneration of caudal fin and liver, we found these hair cell regeneration genes often also affected other types of tissue regeneration. Therefore, our results demonstrate guided screening is an effective approach to discover regeneration candidates, and hair cell regeneration is associated with other tissue regeneration. A study on zebrafish has genetically screened 254 genes and identified 7 genes implicated in the development and regeneration of hair cells and other tissues. Humans and other mammals cannot regrow hair cells—inner-ear sensory receptors that enable hearing—whereas non-mammalian vertebrates, including zebrafish, can regrow these following injury. Researchers from the United States, led by the National Institutes of Health’s Shawn Burgess, screened adult zebrafish for genes active during the regeneration of inner-ear epithelium. The researchers then produced zebrafish without these genes to study their functions. The studies tested 254 genes known to respond during regeneration, and identified seven specifically impacting regeneration. Most of these seven genes also functioned in liver and fin tissue regeneration. Understanding the mechanisms of these genes may enable future research into regenerative therapies in humans.
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18
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Bermedo-García F, Ojeda J, Méndez-Olivos EE, Marcellini S, Larraín J, Henríquez JP. The neuromuscular junction of Xenopus tadpoles: Revisiting a classical model of early synaptogenesis and regeneration. Mech Dev 2018; 154:91-97. [PMID: 29807117 DOI: 10.1016/j.mod.2018.05.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 05/22/2018] [Accepted: 05/23/2018] [Indexed: 11/17/2022]
Abstract
The frog neuromuscular junction (NMJ) has been extensively used as a model system to dissect the mechanisms involved in synapse formation, maturation, maintenance, regeneration, and function. Early NMJ synaptogenesis relies on a combination of cell-autonomous and interdependent pre/postsynaptic communication processes. Due to their transparency, comparatively easy manipulation, and remarkable regenerative abilities, frog tadpoles constitute an excellent model to study NMJ formation and regeneration. Here, we aimed to contribute new aspects on the characterization of the ontogeny of NMJ formation in Xenopus embryos and to explore the morphological changes occurring at the NMJ after spinal cord injury. Following analyses of X. tropicalis tadpoles during development we found that the early pathfinding of rostral motor axons is likely helped by previously formed postsynaptic specializations, whereas NMJ formation in recently differentiated ventral muscles in caudal segments seems to rely on presynaptic inputs. After spinal cord injury of X. laevis tadpoles our results suggest that rostral motor axon projections help caudal NMJ re-innervation before spinal cord connectivity is repaired.
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Affiliation(s)
- Francisca Bermedo-García
- Neuromuscular Studies Laboratory (NeSt Lab), Center for Advanced Microscopy, Faculty of Biological Sciences, Department of Cell Biology, Universidad de Concepción, Concepción, Chile
| | - Jorge Ojeda
- Neuromuscular Studies Laboratory (NeSt Lab), Center for Advanced Microscopy, Faculty of Biological Sciences, Department of Cell Biology, Universidad de Concepción, Concepción, Chile
| | - Emilio E Méndez-Olivos
- Center for Aging and Regeneration, Faculty of Biological Sciences, P. Universidad Católica de Chile, Avenida Libertador Bernardo O'Higgins 340, Santiago, Chile
| | - Sylvain Marcellini
- Laboratory of Development and Evolution (LADE), Department of Cell Biology, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile
| | - Juan Larraín
- Center for Aging and Regeneration, Faculty of Biological Sciences, P. Universidad Católica de Chile, Avenida Libertador Bernardo O'Higgins 340, Santiago, Chile
| | - Juan Pablo Henríquez
- Neuromuscular Studies Laboratory (NeSt Lab), Center for Advanced Microscopy, Faculty of Biological Sciences, Department of Cell Biology, Universidad de Concepción, Concepción, Chile.
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19
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Zebrafish Models of Rare Hereditary Pediatric Diseases. Diseases 2018; 6:diseases6020043. [PMID: 29789451 PMCID: PMC6023479 DOI: 10.3390/diseases6020043] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 05/17/2018] [Accepted: 05/19/2018] [Indexed: 12/12/2022] Open
Abstract
Recent advances in sequencing technologies have made it significantly easier to find the genetic roots of rare hereditary pediatric diseases. These novel methods are not panaceas, however, and they often give ambiguous results, highlighting multiple possible causative mutations in affected patients. Furthermore, even when the mapping results are unambiguous, the affected gene might be of unknown function. In these cases, understanding how a particular genotype can result in a phenotype also needs carefully designed experimental work. Model organism genetics can offer a straightforward experimental setup for hypothesis testing. Containing orthologs for over 80% of the genes involved in human diseases, zebrafish (Danio rerio) has emerged as one of the top disease models over the past decade. A plethora of genetic tools makes it easy to create mutations in almost any gene of the zebrafish genome and these mutant strains can be used in high-throughput preclinical screens for active molecules. As this small vertebrate species offers several other advantages as well, its popularity in biomedical research is bound to increase, with “aquarium to bedside” drug development pipelines taking a more prevalent role in the near future.
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20
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Tejero R, Lopez-Manzaneda M, Arumugam S, Tabares L. Synaptotagmin-2, and -1, linked to neurotransmission impairment and vulnerability in Spinal Muscular Atrophy. Hum Mol Genet 2018; 25:4703-4716. [PMID: 28173138 DOI: 10.1093/hmg/ddw297] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 08/22/2016] [Accepted: 08/23/2016] [Indexed: 01/19/2023] Open
Abstract
Spinal muscular atrophy (SMA) is the most frequent genetic cause of infant mortality. The disease is characterized by progressive muscle weakness and paralysis of axial and proximal limb muscles. It is caused by homozygous loss or mutation of the SMN1 gene, which codes for the Survival Motor Neuron (SMN) protein. In mouse models of the disease, neurotransmitter release is greatly impaired, but the molecular mechanisms of the synaptic dysfunction and the basis of the selective muscle vulnerability are unknown. In the present study, we investigated these open questions by comparing the molecular and functional properties of nerve terminals in severely and mildly affected muscles in the SMNΔ7 mouse model. We discovered that synaptotagmin-1 (Syt1) was developmentally downregulated in nerve terminals of highly affected muscles but not in low vulnerable muscles. Additionally, the expression levels of synaptotagmin-2 (Syt2), and its interacting protein, synaptic vesicle protein 2 (SV2) B, were reduced in proportion to the degree of muscle vulnerability while other synaptic proteins, such as syntaxin-1B (Stx1B) and synaptotagmin-7 (Syt7), were not affected. Consistently with the extremely low levels of both Syt-isoforms, and SV2B, in most affected neuromuscular synapses, the functional analysis of neurotransmission revealed highly reduced evoked release, altered short-term plasticity, low release probability, and inability to modulate normally the number of functional release sites. Together, we propose that the strong reduction of Syt2 and SV2B are key factors of the functional synaptic alteration and that the physiological downregulation of Syt1 plays a determinant role in muscle vulnerability in SMA.
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Affiliation(s)
- Rocío Tejero
- Department of Medical Physiology and Biophysics, School of Medicine, University of Seville, Avda. Sánchez Pizjuán, 4. 41009 Seville, Spain
| | - Mario Lopez-Manzaneda
- Department of Medical Physiology and Biophysics, School of Medicine, University of Seville, Avda. Sánchez Pizjuán, 4. 41009 Seville, Spain
| | - Saravanan Arumugam
- Department of Medical Physiology and Biophysics, School of Medicine, University of Seville, Avda. Sánchez Pizjuán, 4. 41009 Seville, Spain
| | - Lucía Tabares
- Department of Medical Physiology and Biophysics, School of Medicine, University of Seville, Avda. Sánchez Pizjuán, 4. 41009 Seville, Spain
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21
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HuD and the Survival Motor Neuron Protein Interact in Motoneurons and Are Essential for Motoneuron Development, Function, and mRNA Regulation. J Neurosci 2017; 37:11559-11571. [PMID: 29061699 DOI: 10.1523/jneurosci.1528-17.2017] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 09/09/2017] [Indexed: 01/17/2023] Open
Abstract
Motoneurons establish a critical link between the CNS and muscles. If motoneurons do not develop correctly, they cannot form the required connections, resulting in movement defects or paralysis. Compromised development can also lead to degeneration because the motoneuron is not set up to function properly. Little is known, however, regarding the mechanisms that control vertebrate motoneuron development, particularly the later stages of axon branch and dendrite formation. The motoneuron disease spinal muscular atrophy (SMA) is caused by low levels of the survival motor neuron (SMN) protein leading to defects in vertebrate motoneuron development and synapse formation. Here we show using zebrafish as a model system that SMN interacts with the RNA binding protein (RBP) HuD in motoneurons in vivo during formation of axonal branches and dendrites. To determine the function of HuD in motoneurons, we generated zebrafish HuD mutants and found that they exhibited decreased motor axon branches, dramatically fewer dendrites, and movement defects. These same phenotypes are present in animals expressing low levels of SMN, indicating that both proteins function in motoneuron development. HuD binds and transports mRNAs and one of its target mRNAs, Gap43, is involved in axonal outgrowth. We found that Gap43 was decreased in both HuD and SMN mutants. Importantly, transgenic expression of HuD in motoneurons of SMN mutants rescued the motoneuron defects, the movement defects, and Gap43 mRNA levels. These data support that the interaction between SMN and HuD is critical for motoneuron development and point to a role for RBPs in SMA.SIGNIFICANCE STATEMENT In zebrafish models of the motoneuron disease spinal muscular atrophy (SMA), motor axons fail to form the normal extent of axonal branches and dendrites leading to decreased motor function. SMA is caused by low levels of the survival motor neuron (SMN) protein. We show in motoneurons in vivo that SMN interacts with the RNA binding protein, HuD. Novel mutants reveal that HuD is also necessary for motor axonal branch and dendrite formation. Data also revealed that both SMN and HuD affect levels of an mRNA involved in axonal growth. Moreover, expressing HuD in SMN-deficient motoneurons can rescue the motoneuron development and motor defects caused by low levels of SMN. These data support that SMN:HuD complexes are essential for normal motoneuron development and indicate that mRNA handling is a critical component of SMA.
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22
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Dominguez CE, Cunningham D, Chandler DS. SMN regulation in SMA and in response to stress: new paradigms and therapeutic possibilities. Hum Genet 2017; 136:1173-1191. [PMID: 28852871 DOI: 10.1007/s00439-017-1835-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Accepted: 08/07/2017] [Indexed: 12/12/2022]
Abstract
Low levels of the survival of motor neuron (SMN) protein cause the neurodegenerative disease spinal muscular atrophy (SMA). SMA is a pediatric disease characterized by spinal motor neuron degeneration. SMA exhibits several levels of severity ranging from early antenatal fatality to only mild muscular weakness, and disease prognosis is related directly to the amount of functional SMN protein that a patient is able to express. Current therapies are being developed to increase the production of functional SMN protein; however, understanding the effect that natural stresses have on the production and function of SMN is of critical importance to ensuring that these therapies will have the greatest possible effect for patients. Research has shown that SMN, both on the mRNA and protein level, is highly affected by cellular stress. In this review we will summarize the research that highlights the roles of SMN in the disease process and the response of SMN to various environmental stresses.
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Affiliation(s)
- Catherine E Dominguez
- Molecular, Cellular and Developmental Biology Graduate Program and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA
| | - David Cunningham
- Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA
| | - Dawn S Chandler
- Molecular, Cellular and Developmental Biology Graduate Program and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA. .,Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA. .,Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.
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23
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Li W. How do SMA-linked mutations of SMN1 lead to structural/functional deficiency of the SMA protein? PLoS One 2017; 12:e0178519. [PMID: 28570645 PMCID: PMC5453535 DOI: 10.1371/journal.pone.0178519] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 05/15/2017] [Indexed: 11/19/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease with dysfunctional α-motor neurons in the anterior horn of the spinal cord. SMA is caused by loss (∼95% of SMA cases) or mutation (∼5% of SMA cases) of the survival motor neuron 1 gene SMN1. As the product of SMN1, SMN is a component of the SMN complex, and is also involved in the biosynthesis of the small nuclear ribonucleoproteins (snRNPs), which play critical roles in pre-mRNA splicing in the pathogenesis of SMA. To investigate how SMA-linked mutations of SMN1 lead to structural/functional deficiency of SMN, a set of computational analysis of SMN-related structures were conducted and are described in this article. Of extraordinary interest, the structural analysis highlights three SMN residues (Asp44, Glu134 and Gln136) with SMA-linked missense mutations, which cause disruptions of electrostatic interactions for Asp44, Glu134 and Gln136, and result in three functionally deficient SMA-linked SMN mutants, Asp44Val, Glu134Lys and Gln136Glu. From the computational analysis, it is also possible that SMN’s Lys45 and Asp36 act as two electrostatic clips at the SMN-Gemin2 complex structure interface.
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Affiliation(s)
- Wei Li
- Medical College, Shantou University, Shantou City, Guangdong Province, China
- * E-mail:
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24
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Singh RN, Howell MD, Ottesen EW, Singh NN. Diverse role of survival motor neuron protein. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2017; 1860:299-315. [PMID: 28095296 PMCID: PMC5325804 DOI: 10.1016/j.bbagrm.2016.12.008] [Citation(s) in RCA: 178] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 12/23/2016] [Accepted: 12/30/2016] [Indexed: 02/07/2023]
Abstract
The multifunctional Survival Motor Neuron (SMN) protein is required for the survival of all organisms of the animal kingdom. SMN impacts various aspects of RNA metabolism through the formation and/or interaction with ribonucleoprotein (RNP) complexes. SMN regulates biogenesis of small nuclear RNPs, small nucleolar RNPs, small Cajal body-associated RNPs, signal recognition particles and telomerase. SMN also plays an important role in DNA repair, transcription, pre-mRNA splicing, histone mRNA processing, translation, selenoprotein synthesis, macromolecular trafficking, stress granule formation, cell signaling and cytoskeleton maintenance. The tissue-specific requirement of SMN is dictated by the variety and the abundance of its interacting partners. Reduced expression of SMN causes spinal muscular atrophy (SMA), a leading genetic cause of infant mortality. SMA displays a broad spectrum ranging from embryonic lethality to an adult onset. Aberrant expression and/or localization of SMN has also been associated with male infertility, inclusion body myositis, amyotrophic lateral sclerosis and osteoarthritis. This review provides a summary of various SMN functions with implications to a better understanding of SMA and other pathological conditions.
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Affiliation(s)
- Ravindra N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States.
| | - Matthew D Howell
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States
| | - Eric W Ottesen
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States
| | - Natalia N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States
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25
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Holloway MP, DeNardo BD, Phornphutkul C, Nguyen K, Davis C, Jackson C, Richendrfer H, Creton R, Altura RA. An asymptomatic mutation complicating severe chemotherapy-induced peripheral neuropathy (CIPN): a case for personalised medicine and a zebrafish model of CIPN. NPJ Genom Med 2016; 1:16016. [PMID: 29263815 PMCID: PMC5685301 DOI: 10.1038/npjgenmed.2016.16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 04/20/2016] [Accepted: 04/22/2016] [Indexed: 12/13/2022] Open
Abstract
Targeted next-generation sequencing (NGS) identified a novel loss of function mutation in GARS, a gene linked to Charcot-Marie-Tooth disease (CMT), in a paediatric acute lymphoblastic leukaemia patient with severe chemotherapy-induced peripheral neuropathy (CIPN) due to vincristine. The patient was clinically asymptomatic, and lacked a family history of neuropathy. The effect of the mutation was modelled in a zebrafish knockdown system that recapitulated the symptoms of the patient both prior to and after treatment with vincristine. Confocal microscopy of pre- and post-synaptic markers revealed that the GARS knockdown results in changes to peripheral motor neurons, acetylcholine receptors and their co-localisation in neuromuscular junctions (NMJs), whereas a sensitive and reproducible stimulus-response assay demonstrated that the changes correlating with the GARS mutation in themselves fail to produce peripheral neuropathy symptoms. However, with vincristine treatment the GARS knockdown exacerbates decreased stimulus response and NMJ lesions. We propose that there is substantial benefit in the use of a targeted NGS screen of cancer patients who are to be treated with microtubule targeting agents for deleterious mutations in CMT linked genes, and for the screening in zebrafish of reagents that might inhibit CIPN.
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Affiliation(s)
- Michael P Holloway
- Department of Pediatrics, Division of Pediatric Hematology-Oncology, Hasbro Children’s Hospital and The Warren Alpert Medical School at Brown University, Providence, RI, USA
| | - Bradley D DeNardo
- Department of Pediatrics, Division of Pediatric Hematology-Oncology, Hasbro Children’s Hospital and The Warren Alpert Medical School at Brown University, Providence, RI, USA
| | - Chanika Phornphutkul
- Department of Pediatrics, Division of Pediatric Endocrinology and Metabolism, Rhode Island Hospital and Brown University, Providence, RI, USA
| | - Kevin Nguyen
- Department of Pediatrics, Division of Pediatric Hematology-Oncology, Hasbro Children’s Hospital and The Warren Alpert Medical School at Brown University, Providence, RI, USA
| | - Colby Davis
- Department of Pediatrics, Division of Pediatric Hematology-Oncology, Hasbro Children’s Hospital and The Warren Alpert Medical School at Brown University, Providence, RI, USA
| | - Cynthia Jackson
- Departments of Pathology and Clinical Molecular Biology, Rhode Island Hospital and Brown University School of Medicine, Providence, RI, USA
| | - Holly Richendrfer
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, USA
| | - Robbert Creton
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, USA
| | - Rachel A Altura
- Department of Pediatrics, Division of Pediatric Hematology-Oncology, Hasbro Children’s Hospital and The Warren Alpert Medical School at Brown University, Providence, RI, USA
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26
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Gallotta I, Mazzarella N, Donato A, Esposito A, Chaplin JC, Castro S, Zampi G, Battaglia GS, Hilliard MA, Bazzicalupo P, Di Schiavi E. Neuron-specific knock-down of SMN1 causes neuron degeneration and death through an apoptotic mechanism. Hum Mol Genet 2016; 25:2564-2577. [PMID: 27260405 PMCID: PMC5181630 DOI: 10.1093/hmg/ddw119] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 04/12/2016] [Accepted: 04/13/2016] [Indexed: 12/31/2022] Open
Abstract
Spinal muscular atrophy is a devastating disease that is characterized by degeneration and death of a specific subclass of motor neurons in the anterior horn of the spinal cord. Although the gene responsible, survival motor neuron 1 (SMN1), was identified 20 years ago, it has proven difficult to investigate its effects in vivo. Consequently, a number of key questions regarding the molecular and cellular functions of this molecule have remained unanswered. We developed a Caenorhabditis elegans model of smn-1 loss-of-function using a neuron-specific RNA interference strategy to knock-down smn-1 selectively in a subclass of motor neurons. The transgenic animals presented a cell-autonomous, age-dependent degeneration of motor neurons detected as locomotory defects and the disappearance of presynaptic and cytoplasmic fluorescent markers in targeted neurons. This degeneration led to neuronal death as revealed by positive reactivity to genetic and chemical cell-death markers. We show that genes of the classical apoptosis pathway are involved in the smn-1-mediated neuronal death, and that this phenotype can be rescued by the expression of human SMN1, indicating a functional conservation between the two orthologs. Finally, we determined that Plastin3/plst-1 genetically interacts with smn-1 to prevent degeneration, and that treatment with valproic acid is able to rescue the degenerative phenotype. These results provide novel insights into the cellular and molecular mechanisms that lead to the loss of motor neurons when SMN1 function is reduced.
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Affiliation(s)
- Ivan Gallotta
- Institute of Genetics and Biophysics (IGB) "Adriano Buzzati-Traverso", Consiglio Nazionale delle Ricerche (CNR), Via P. Castellino 111, 80131 Napoli, Italy.,Institute of Bioscience and Bioresources (IBBR), Consiglio Nazionale delle Ricerche (CNR), Via P. Castellino 111, 80131 Napoli, Italy
| | - Nadia Mazzarella
- Institute of Genetics and Biophysics (IGB) "Adriano Buzzati-Traverso", Consiglio Nazionale delle Ricerche (CNR), Via P. Castellino 111, 80131 Napoli, Italy.,Institute of Bioscience and Bioresources (IBBR), Consiglio Nazionale delle Ricerche (CNR), Via P. Castellino 111, 80131 Napoli, Italy
| | - Alessandra Donato
- Institute of Genetics and Biophysics (IGB) "Adriano Buzzati-Traverso", Consiglio Nazionale delle Ricerche (CNR), Via P. Castellino 111, 80131 Napoli, Italy.,Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute (QBI), The University of Queensland, Brisbane, QLD 4072, Australia
| | - Alessandro Esposito
- Institute of Genetics and Biophysics (IGB) "Adriano Buzzati-Traverso", Consiglio Nazionale delle Ricerche (CNR), Via P. Castellino 111, 80131 Napoli, Italy
| | - Justin C Chaplin
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute (QBI), The University of Queensland, Brisbane, QLD 4072, Australia
| | - Silvana Castro
- Institute of Genetics and Biophysics (IGB) "Adriano Buzzati-Traverso", Consiglio Nazionale delle Ricerche (CNR), Via P. Castellino 111, 80131 Napoli, Italy
| | - Giuseppina Zampi
- Institute of Genetics and Biophysics (IGB) "Adriano Buzzati-Traverso", Consiglio Nazionale delle Ricerche (CNR), Via P. Castellino 111, 80131 Napoli, Italy.,Institute of Bioscience and Bioresources (IBBR), Consiglio Nazionale delle Ricerche (CNR), Via P. Castellino 111, 80131 Napoli, Italy
| | | | - Massimo A Hilliard
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute (QBI), The University of Queensland, Brisbane, QLD 4072, Australia
| | - Paolo Bazzicalupo
- Institute of Genetics and Biophysics (IGB) "Adriano Buzzati-Traverso", Consiglio Nazionale delle Ricerche (CNR), Via P. Castellino 111, 80131 Napoli, Italy.,Institute of Bioscience and Bioresources (IBBR), Consiglio Nazionale delle Ricerche (CNR), Via P. Castellino 111, 80131 Napoli, Italy
| | - Elia Di Schiavi
- Institute of Genetics and Biophysics (IGB) "Adriano Buzzati-Traverso", Consiglio Nazionale delle Ricerche (CNR), Via P. Castellino 111, 80131 Napoli, Italy .,Institute of Bioscience and Bioresources (IBBR), Consiglio Nazionale delle Ricerche (CNR), Via P. Castellino 111, 80131 Napoli, Italy
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27
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Donlin-Asp PG, Bassell GJ, Rossoll W. A role for the survival of motor neuron protein in mRNP assembly and transport. Curr Opin Neurobiol 2016; 39:53-61. [PMID: 27131421 DOI: 10.1016/j.conb.2016.04.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 03/27/2016] [Accepted: 04/13/2016] [Indexed: 02/08/2023]
Abstract
Localization and local translation of mRNA plays a key role in neuronal development and function. While studies in various systems have provided insights into molecular mechanisms of mRNA transport and local protein synthesis, the factors that control the assembly of mRNAs and mRNA binding proteins into messenger ribonucleoprotein (mRNP) transport granules remain largely unknown. In this review we will discuss how insights on a motor neuron disease, spinal muscular atrophy (SMA), is advancing our understanding of regulated assembly of transport competent mRNPs and how defects in their assembly and delivery may contribute to the degeneration of motor neurons observed in SMA and other neurological disorders.
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Affiliation(s)
- Paul G Donlin-Asp
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Gary J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA; Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA.
| | - Wilfried Rossoll
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA.
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28
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Seytanoglu A, Alsomali NI, Valori CF, McGown A, Kim HR, Ning K, Ramesh T, Sharrack B, Wood JD, Azzouz M. Deficiency in the mRNA export mediator Gle1 impairs Schwann cell development in the zebrafish embryo. Neuroscience 2016; 322:287-97. [PMID: 26921650 DOI: 10.1016/j.neuroscience.2016.02.039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 02/17/2016] [Accepted: 02/17/2016] [Indexed: 12/12/2022]
Abstract
GLE1 mutations cause lethal congenital contracture syndrome 1 (LCCS1), a severe autosomal recessive fetal motor neuron disease, and more recently have been associated with amyotrophic lateral sclerosis (ALS). The gene encodes a highly conserved protein with an essential role in mRNA export. The mechanism linking Gle1 function to motor neuron degeneration in humans has not been elucidated, but increasing evidence implicates abnormal RNA processing as a key event in the pathogenesis of several motor neuron diseases. Homozygous gle1(-/-) mutant zebrafish display various aspects of LCCS, showing severe developmental abnormalities including motor neuron arborization defects and embryonic lethality. A previous gene expression study on spinal cord from LCCS fetuses indicated that oligodendrocyte dysfunction may be an important factor in LCCS. We therefore set out to investigate the development of myelinating glia in gle1(-/-) mutant zebrafish embryos. While expression of myelin basic protein (mbp) in hindbrain oligodendrocytes appeared relatively normal, our studies revealed a prominent defect in Schwann cell precursor proliferation and differentiation in the posterior lateral line nerve. Other genes mutated in LCCS have important roles in Schwann cell development, thereby suggesting that Schwann cell deficits may be a common factor in LCCS pathogenesis. These findings illustrate the potential importance of glial cells such as myelinating Schwann cells in motor neuron diseases linked to RNA processing defects.
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Affiliation(s)
- A Seytanoglu
- The Sheffield Institute for Translational Neuroscience, Department of Neuroscience, University of Sheffield, 385A Glossop Road, Sheffield S10 2HQ, UK
| | - N I Alsomali
- The Sheffield Institute for Translational Neuroscience, Department of Neuroscience, University of Sheffield, 385A Glossop Road, Sheffield S10 2HQ, UK
| | - C F Valori
- The Sheffield Institute for Translational Neuroscience, Department of Neuroscience, University of Sheffield, 385A Glossop Road, Sheffield S10 2HQ, UK
| | - A McGown
- The Sheffield Institute for Translational Neuroscience, Department of Neuroscience, University of Sheffield, 385A Glossop Road, Sheffield S10 2HQ, UK
| | - H R Kim
- Bateson Centre, Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - K Ning
- The Sheffield Institute for Translational Neuroscience, Department of Neuroscience, University of Sheffield, 385A Glossop Road, Sheffield S10 2HQ, UK
| | - T Ramesh
- The Sheffield Institute for Translational Neuroscience, Department of Neuroscience, University of Sheffield, 385A Glossop Road, Sheffield S10 2HQ, UK
| | - B Sharrack
- The Sheffield Institute for Translational Neuroscience, Department of Neuroscience, University of Sheffield, 385A Glossop Road, Sheffield S10 2HQ, UK; Department of Neurology, Royal Hallamshire Hospital, Sheffield Teaching Hospitals Foundation Trust, Glossop Road, Sheffield S10 2JF, UK
| | - J D Wood
- The Sheffield Institute for Translational Neuroscience, Department of Neuroscience, University of Sheffield, 385A Glossop Road, Sheffield S10 2HQ, UK; Bateson Centre, Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - M Azzouz
- The Sheffield Institute for Translational Neuroscience, Department of Neuroscience, University of Sheffield, 385A Glossop Road, Sheffield S10 2HQ, UK; Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia.
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29
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Laird AS, Mackovski N, Rinkwitz S, Becker TS, Giacomotto J. Tissue-specific models of spinal muscular atrophy confirm a critical role of SMN in motor neurons from embryonic to adult stages. Hum Mol Genet 2016; 25:1728-38. [PMID: 26908606 DOI: 10.1093/hmg/ddw044] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 02/15/2016] [Indexed: 11/14/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive disease linked to survival motor neuron (SMN) protein deficiency. While SMN protein is expressed ubiquitously, its deficiency triggers tissue-specific hallmarks, including motor neuron death and muscle atrophy, leading to impaired motor functions and premature death. Here, using stable miR-mediated knockdown technology in zebrafish, we developed the first vertebrate system allowing transgenic spatio-temporal control of the smn1 gene. Using this new model it is now possible to investigate normal and pathogenic SMN function(s) in specific cell types, independently or in synergy with other cell populations. We took advantage of this new system to first test the effect of motor neuron or muscle-specific smn1 silencing. Anti-smn1 miRNA expression in motor neurons, but not in muscles, reproduced SMA hallmarks, including abnormal motor neuron development, poor motor function and premature death. Interestingly, smn1 knockdown in motor neurons also induced severe late-onset phenotypes including scoliosis-like body deformities, weight loss, muscle atrophy and, seen for the first time in zebrafish, reduction in the number of motor neurons, indicating motor neuron degeneration. Taken together, we have developed a new transgenic system allowing spatio-temporal control of smn1 expression in zebrafish, and using this model, we have demonstrated that smn1 silencing in motor neurons alone is sufficient to reproduce SMA hallmarks in zebrafish. It is noteworthy that this research is going beyond SMA as this versatile gene-silencing transgenic system can be used to knockdown any genes of interest, filling the gap in the zebrafish genetic toolbox and opening new avenues to study gene functions in this organism.
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Affiliation(s)
- Angela S Laird
- ANZAC Research Institute, Concord Repatriation Hospital, University of Sydney, Sydney, New South Wales, Australia, Department of Biomedical Sciences, Faculty of Medicine & Health Sciences, Macquarie University, Sydney, Australia
| | - Nikolce Mackovski
- ANZAC Research Institute, Concord Repatriation Hospital, University of Sydney, Sydney, New South Wales, Australia
| | - Silke Rinkwitz
- Brain and Mind Research Institute, Sydney Medical School, University of Sydney, Camperdown, New South Wales 2050, Australia and
| | - Thomas S Becker
- Brain and Mind Research Institute, Sydney Medical School, University of Sydney, Camperdown, New South Wales 2050, Australia and
| | - Jean Giacomotto
- Brain and Mind Research Institute, Sydney Medical School, University of Sydney, Camperdown, New South Wales 2050, Australia and Queensland Brain Institute, The University of Queensland, Building #79, St Lucia, Queensland 4072, Australia
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30
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Qiu W, Zhao Y, Yang M, Farajzadeh M, Pan C, Wayne NL. Actions of Bisphenol A and Bisphenol S on the Reproductive Neuroendocrine System During Early Development in Zebrafish. Endocrinology 2016; 157:636-47. [PMID: 26653335 DOI: 10.1210/en.2015-1785] [Citation(s) in RCA: 136] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Bisphenol A (BPA) is a well-known environmental, endocrine-disrupting chemical, and bisphenol S (BPS) has been considered a safer alternative for BPA-free products. The present study aims to evaluate the impact of BPA and BPS on the reproductive neuroendocrine system during zebrafish embryonic and larval development and to explore potential mechanisms of action associated with estrogen receptor (ER), thyroid hormone receptor (THR), and enzyme aromatase (AROM) pathways. Environmentally relevant, low levels of BPA exposure during development led to advanced hatching time, increased numbers of GnRH3 neurons in both terminal nerve and hypothalamus, increased expression of reproduction-related genes (kiss1, kiss1r, gnrh3, lhβ, fshβ, and erα), and a marker for synaptic transmission (sv2). Low levels of BPS exposure led to similar effects: increased numbers of hypothalamic GnRH3 neurons and increased expression of kiss1, gnrh3, and erα. Antagonists of ER, THRs, and AROM blocked many of the effects of BPA and BPS on reproduction-related gene expression, providing evidence that those three pathways mediate the actions of BPA and BPS on the reproductive neuroendocrine system. This study demonstrates that alternatives to BPA used in the manufacture of BPA-free products are not necessarily safer. Furthermore, this is the first study to describe the impact of low-level BPA and BPS exposure on the Kiss/Kiss receptor system during development. It is also the first report of multiple cellular pathways (ERα, THRs, and AROM) mediating the effects of BPA and BPS during embryonic development in any species.
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Affiliation(s)
- Wenhui Qiu
- School of Environmental and Chemical Engineering (W.Q., M.Y., C.P.), Shanghai University, Shanghai 200444, China; and Department of Physiology (W.Q., Y.Z., M.F., N.L.W.), David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California 90095
| | - Yali Zhao
- School of Environmental and Chemical Engineering (W.Q., M.Y., C.P.), Shanghai University, Shanghai 200444, China; and Department of Physiology (W.Q., Y.Z., M.F., N.L.W.), David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California 90095
| | - Ming Yang
- School of Environmental and Chemical Engineering (W.Q., M.Y., C.P.), Shanghai University, Shanghai 200444, China; and Department of Physiology (W.Q., Y.Z., M.F., N.L.W.), David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California 90095
| | - Matthew Farajzadeh
- School of Environmental and Chemical Engineering (W.Q., M.Y., C.P.), Shanghai University, Shanghai 200444, China; and Department of Physiology (W.Q., Y.Z., M.F., N.L.W.), David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California 90095
| | - Chenyuan Pan
- School of Environmental and Chemical Engineering (W.Q., M.Y., C.P.), Shanghai University, Shanghai 200444, China; and Department of Physiology (W.Q., Y.Z., M.F., N.L.W.), David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California 90095
| | - Nancy L Wayne
- School of Environmental and Chemical Engineering (W.Q., M.Y., C.P.), Shanghai University, Shanghai 200444, China; and Department of Physiology (W.Q., Y.Z., M.F., N.L.W.), David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California 90095
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31
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Stil A, Drapeau P. Neuronal labeling patterns in the spinal cord of adult transgenic Zebrafish. Dev Neurobiol 2015; 76:642-60. [PMID: 26408263 DOI: 10.1002/dneu.22350] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 09/13/2015] [Accepted: 09/14/2015] [Indexed: 01/20/2023]
Abstract
We describe neuronal patterns in the spinal cord of adult zebrafish. We studied the distribution of cells and processes in the three spinal regions reported in the literature: the 8th vertebra used as a transection injury site, the 15th vertebra mainly used for motor cell recordings and also for crush injury, and the 24th vertebra used to record motor nerve activity. We used well-known transgenic lines in which expression of green fluorescent protein (GFP) is driven by promoters to hb9 and isl1 in motoneurons, alx/chx10 and evx1 interneurons, ngn1 in sensory neurons and olig2 in oligodendrocytes, as well as antibodies for neurons (HuC/D, NF and SV2) and glia (GFAP). In isl1:GFP fish, GFP-positive processes are retained in the upper part of ventral horns and two subsets of cell bodies are observed. The pattern of the transgene in hb9:GFP adults is more diffuse and fibers are present broadly through the adult spinal cord. In alx/chx10 and evx1 lines we respectively observed two and three different GFP-positive populations. Finally, the ngn1:GFP transgene identifies dorsal root ganglion and some cells in dorsal horns. Interestingly some GFP positive fibers in ngn1:GFP fish are located around Mauthner axons and their density seems to be related to a rostrocaudal gradient. Many other cell types have been described in embryos and need to be studied in adults. Our findings provide a reference for further studies on spinal cytoarchitecture. Combined with physiological, histological and pathological/traumatic approaches, these studies will help clarify the operation of spinal locomotor circuits of adult zebrafish.
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Affiliation(s)
- Aurélie Stil
- Hospital Research Centre (CRCHUM) and Department of Neurosciences, Université de Montréal, Montréal, Quebec, Canada, H2X 0A9
| | - Pierre Drapeau
- Hospital Research Centre (CRCHUM) and Department of Neurosciences, Université de Montréal, Montréal, Quebec, Canada, H2X 0A9
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32
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Giacomotto J, Rinkwitz S, Becker TS. Effective heritable gene knockdown in zebrafish using synthetic microRNAs. Nat Commun 2015; 6:7378. [PMID: 26051838 PMCID: PMC4468906 DOI: 10.1038/ncomms8378] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 05/01/2015] [Indexed: 12/22/2022] Open
Abstract
Although zebrafish is used to model human diseases through mutational and morpholino-based knockdown approaches, there are currently no robust transgenic knockdown tools. Here we investigate the knockdown efficiency of three synthetic miRNA-expressing backbones and show that these constructs can downregulate a sensor transgene with different degrees of potency. Using this approach, we reproduce spinal muscular atrophy (SMA) in zebrafish by targeting the smn1 gene. We also generate different transgenic lines, with severity and age of onset correlated to the level of smn1 inhibition, recapitulating for the first time the different forms of SMA in zebrafish. These lines are proof-of-concept that miRNA-based approaches can be used to generate potent heritable gene knockdown in zebrafish. Zebrafish is a model system for which for no reliable heritable gene silencing method is available. Here the authors provide a system for heritable miRNA-mediated knockdown and demonstrate tunable silencing of the smn1 gene that recapitulate different forms of spinal muscular atrophy.
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Affiliation(s)
- Jean Giacomotto
- Brain and Mind Research Institute, Sydney Medical School, University of Sydney, Camperdown, New South Wales 2050, Australia
| | - Silke Rinkwitz
- Brain and Mind Research Institute, Sydney Medical School, University of Sydney, Camperdown, New South Wales 2050, Australia.,Department of Physiology, Sydney Medical School, University of Sydney, Camperdown, New South Wales 2050, Australia
| | - Thomas S Becker
- Brain and Mind Research Institute, Sydney Medical School, University of Sydney, Camperdown, New South Wales 2050, Australia.,Department of Physiology, Sydney Medical School, University of Sydney, Camperdown, New South Wales 2050, Australia
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33
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Faller KME, Gutierrez-Quintana R, Mohammed A, Rahim AA, Tuxworth RI, Wager K, Bond M. The neuronal ceroid lipofuscinoses: Opportunities from model systems. Biochim Biophys Acta Mol Basis Dis 2015; 1852:2267-78. [PMID: 25937302 DOI: 10.1016/j.bbadis.2015.04.022] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 04/13/2015] [Accepted: 04/22/2015] [Indexed: 12/16/2022]
Abstract
The neuronal ceroid lipofuscinoses are a group of severe and progressive neurodegenerative disorders, generally with childhood onset. Despite the fact that these diseases remain fatal, significant breakthroughs have been made in our understanding of the genetics that underpin these conditions. This understanding has allowed the development of a broad range of models to study disease processes, and to develop new therapeutic approaches. Such models have contributed significantly to our knowledge of these conditions. In this review we will focus on the advantages of each individual model, describe some of the contributions the models have made to our understanding of the broader disease biology and highlight new techniques and approaches relevant to the study and potential treatment of the neuronal ceroid lipofuscinoses. This article is part of a Special Issue entitled: "Current Research on the Neuronal Ceroid Lipofuscinoses (Batten Disease)".
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Affiliation(s)
- Kiterie M E Faller
- School of Veterinary Medicine, College of Veterinary, Medical and Life Sciences, Bearsden Road, Glasgow G61 1QH, UK
| | - Rodrigo Gutierrez-Quintana
- School of Veterinary Medicine, College of Veterinary, Medical and Life Sciences, Bearsden Road, Glasgow G61 1QH, UK
| | - Alamin Mohammed
- College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Ahad A Rahim
- UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, UK
| | - Richard I Tuxworth
- College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Kim Wager
- Cardiff School of Biosciences, Cardiff University, The Sir Martin Evans Building, Museum Avenue, Cardiff CF10 3AX, UK
| | - Michael Bond
- MRC Laboratory for Molecular Cell Biology, University College of London, Gower Street, London WC1E 6BT, UK.
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Edens BM, Ajroud-Driss S, Ma L, Ma YC. Molecular mechanisms and animal models of spinal muscular atrophy. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1852:685-92. [PMID: 25088406 DOI: 10.1016/j.bbadis.2014.07.024] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 07/21/2014] [Accepted: 07/23/2014] [Indexed: 12/27/2022]
Abstract
Spinal muscular atrophy (SMA), the leading genetic cause of infant mortality, is characterized by the degeneration of spinal motor neurons and muscle atrophy. Although the genetic cause of SMA has been mapped to the Survival Motor Neuron1 (SMN1) gene, mechanisms underlying selective motor neuron degeneration in SMA remain largely unknown. Here we review the latest developments and our current understanding of the molecular mechanisms underlying SMA pathogenesis, focusing on the animal model systems that have been developed, as well as new diagnostic and treatment strategies that have been identified using these model systems. This article is part of a special issue entitled: Neuromuscular Diseases: Pathology and Molecular Pathogenesis.
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Affiliation(s)
- Brittany M Edens
- Departments of Pediatrics, Neurology and Physiology, Northwestern University Feinberg School of Medicine, Lurie Children's Hospital of Chicago Research Center, IL 60611, Chicago
| | | | - Long Ma
- State Key Laboratory of Medical Genetics, Central South University, Changsha, Hunan 410078, China
| | - Yong-Chao Ma
- Departments of Pediatrics, Neurology and Physiology, Northwestern University Feinberg School of Medicine, Lurie Children's Hospital of Chicago Research Center, IL 60611, Chicago.
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Lattante S, de Calbiac H, Le Ber I, Brice A, Ciura S, Kabashi E. Sqstm1 knock-down causes a locomotor phenotype ameliorated by rapamycin in a zebrafish model of ALS/FTLD. Hum Mol Genet 2014; 24:1682-90. [PMID: 25410659 DOI: 10.1093/hmg/ddu580] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Mutations in SQSTM1, encoding for the protein SQSTM1/p62, have been recently reported in 1-3.5% of patients with amyotrophic lateral sclerosis and frontotemporal lobar degeneration (ALS/FTLD). Inclusions positive for SQSTM1/p62 have been detected in patients with neurodegenerative disorders, including ALS/FTLD. In order to investigate the pathogenic mechanisms induced by SQSTM1 mutations in ALS/FTLD, we developed a zebrafish model. Knock-down of the sqstm1 zebrafish ortholog, as well as impairment of its splicing, led to a specific phenotype, consisting of behavioral and axonal anomalies. Here, we report swimming deficits associated with shorter motor neuronal axons that could be rescued by the overexpression of wild-type human SQSTM1. Interestingly, no rescue of the loss-of-function phenotype was observed when overexpressing human SQSTM1 constructs carrying ALS/FTLD-related mutations. Consistent with its role in autophagy regulation, we found increased mTOR levels upon knock-down of sqstm1. Furthermore, treatment of zebrafish embryos with rapamycin, a known inhibitor of the mTOR pathway, yielded an amelioration of the locomotor phenotype in the sqstm1 knock-down model. Our results suggest that loss-of-function of SQSTM1 causes phenotypic features characterized by locomotor deficits and motor neuron axonal defects that are associated with a misregulation of autophagic processes.
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Affiliation(s)
- Serena Lattante
- Sorbonne Université, UPMC Univ Paris 06, UM 75, ICM; Inserm, U 1127, ICM; Cnrs, UMR 7225, ICM; ICM, Paris, F-75013 Paris, France
| | - Hortense de Calbiac
- Sorbonne Université, UPMC Univ Paris 06, UM 75, ICM; Inserm, U 1127, ICM; Cnrs, UMR 7225, ICM; ICM, Paris, F-75013 Paris, France
| | - Isabelle Le Ber
- Sorbonne Université, UPMC Univ Paris 06, UM 75, ICM; Inserm, U 1127, ICM; Cnrs, UMR 7225, ICM; ICM, Paris, F-75013 Paris, France, AP-HP, Hôpital de la Salpêtrière, Centre de Référence Démences Rares, F-75013, Paris, France
| | - Alexis Brice
- Sorbonne Université, UPMC Univ Paris 06, UM 75, ICM; Inserm, U 1127, ICM; Cnrs, UMR 7225, ICM; ICM, Paris, F-75013 Paris, France, AP-HP, Hôpital de la Salpêtrière, Département de Génétique et Cytogénétique, F-75013, Paris, France
| | - Sorana Ciura
- Sorbonne Université, UPMC Univ Paris 06, UM 75, ICM; Inserm, U 1127, ICM; Cnrs, UMR 7225, ICM; ICM, Paris, F-75013 Paris, France,
| | - Edor Kabashi
- Sorbonne Université, UPMC Univ Paris 06, UM 75, ICM; Inserm, U 1127, ICM; Cnrs, UMR 7225, ICM; ICM, Paris, F-75013 Paris, France,
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PTEN depletion decreases disease severity and modestly prolongs survival in a mouse model of spinal muscular atrophy. Mol Ther 2014; 23:270-7. [PMID: 25369768 PMCID: PMC4445616 DOI: 10.1038/mt.2014.209] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 10/21/2014] [Indexed: 12/13/2022] Open
Abstract
Spinal muscular atrophy (SMA) is the second most common genetic cause of death in childhood. However, no effective treatment is available to halt disease progression. SMA is caused by mutations in the survival motor neuron 1 (SMN1) gene. We previously reported that PTEN depletion leads to an increase in survival of SMN-deficient motor neurons. Here, we aimed to establish the impact of PTEN modulation in an SMA mouse model in vivo. Initial experiments using intramuscular delivery of adeno-associated vector serotype 6 (AAV6) expressing shRNA against PTEN in an established mouse model of severe SMA (SMNΔ7) demonstrated the ability to ameliorate the severity of neuromuscular junction pathology. Subsequently, we developed self-complementary AAV9 expressing siPTEN (scAAV9-siPTEN) to allow evaluation of the effect of systemic suppression of PTEN on the disease course of SMA in vivo. Treatment with a single injection of scAAV9-siPTEN at postnatal day 1 resulted in a modest threefold extension of the lifespan of SMNΔ7 mice, increasing mean survival to 30 days, compared to 10 days in untreated mice. Our data revealed that systemic PTEN depletion is an important disease modifier in SMNΔ7 mice, and therapies aimed at lowering PTEN expression may therefore offer a potential therapeutic strategy for SMA.
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Hao LT, Duy PQ, Jontes JD, Beattie CE. Motoneuron development influences dorsal root ganglia survival and Schwann cell development in a vertebrate model of spinal muscular atrophy. Hum Mol Genet 2014; 24:346-60. [PMID: 25180019 DOI: 10.1093/hmg/ddu447] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Low levels of the survival motor neuron protein (SMN) cause the disease spinal muscular atrophy. A primary characteristic of this disease is motoneuron dysfunction and paralysis. Understanding why motoneurons are affected by low levels of SMN will lend insight into this disease and to motoneuron biology in general. Motoneurons in zebrafish smn mutants develop abnormally; however, it is unclear where Smn is needed for motoneuron development since it is a ubiquitously expressed protein. We have addressed this issue by expressing human SMN in motoneurons in zebrafish maternal-zygotic (mz) smn mutants. First, we demonstrate that SMN is present in axons, but only during the period of robust motor axon outgrowth. We also conclusively demonstrate that SMN acts cell autonomously in motoneurons for proper motoneuron development. This includes the formation of both axonal and dendritic branches. Analysis of the peripheral nervous system revealed that Schwann cells and dorsal root ganglia (DRG) neurons developed abnormally in mz-smn mutants. Schwann cells did not wrap axons tightly and had expanded nodes of Ranvier. The majority of DRG neurons had abnormally short peripheral axons and later many of them failed to divide and died. Expressing SMN just in motoneurons rescued both of these cell types showing that their failure to develop was secondary to the developmental defects in motoneurons. Driving SMN just in motoneurons did not increase survival of the animal, suggesting that SMN is needed for motoneuron development and motor circuitry, but that SMN in other cells types factors into survival.
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Affiliation(s)
- Le Thi Hao
- Department of Neuroscience, The Ohio State University College of Medicine, 190 Rightmire Hall, 1060 Carmack Rd, Columbus, OH 43210, USA
| | - Phan Q Duy
- Department of Neuroscience, The Ohio State University College of Medicine, 190 Rightmire Hall, 1060 Carmack Rd, Columbus, OH 43210, USA
| | - James D Jontes
- Department of Neuroscience, The Ohio State University College of Medicine, 190 Rightmire Hall, 1060 Carmack Rd, Columbus, OH 43210, USA
| | - Christine E Beattie
- Department of Neuroscience, The Ohio State University College of Medicine, 190 Rightmire Hall, 1060 Carmack Rd, Columbus, OH 43210, USA
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Zhao Y, Lin MCA, Mock A, Yang M, Wayne NL. Kisspeptins modulate the biology of multiple populations of gonadotropin-releasing hormone neurons during embryogenesis and adulthood in zebrafish (Danio rerio). PLoS One 2014; 9:e104330. [PMID: 25093675 PMCID: PMC4122407 DOI: 10.1371/journal.pone.0104330] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 07/12/2014] [Indexed: 11/19/2022] Open
Abstract
Kisspeptin1 (product of the Kiss1 gene) is the key neuropeptide that gates puberty and maintains fertility by regulating the gonadotropin-releasing hormone (GnRH) neuronal system in mammals. Inactivating mutations in Kiss1 and the kisspeptin receptor (GPR54/Kiss1r) are associated with pubertal failure and infertility. Kiss2, a paralogous gene for kiss1, has been recently identified in several vertebrates including zebrafish. Using our transgenic zebrafish model system in which the GnRH3 promoter drives expression of emerald green fluorescent protein, we investigated the effects of kisspeptins on development of the GnRH neuronal system during embryogenesis and on electrical activity during adulthood. Quantitative PCR showed detectable levels of kiss1 and kiss2 mRNA by 1 day post fertilization, increasing throughout embryonic and larval development. Early treatment with Kiss1 or Kiss2 showed that both kisspeptins stimulated proliferation of trigeminal GnRH3 neurons located in the peripheral nervous system. However, only Kiss1, but not Kiss2, stimulated proliferation of terminal nerve and hypothalamic populations of GnRH3 neurons in the central nervous system. Immunohistochemical analysis of synaptic vesicle protein 2 suggested that Kiss1, but not Kiss2, increased synaptic contacts on the cell body and along the terminal nerve-GnRH3 neuronal processes during embryogenesis. In intact brain of adult zebrafish, whole-cell patch clamp recordings of GnRH3 neurons from the preoptic area and hypothalamus revealed opposite effects of Kiss1 and Kiss2 on spontaneous action potential firing frequency and membrane potential. Kiss1 increased spike frequency and depolarized membrane potential, whereas Kiss2 suppressed spike frequency and hyperpolarized membrane potential. We conclude that in zebrafish, Kiss1 is the primary stimulator of GnRH3 neuronal development in the embryo and an activator of stimulating hypophysiotropic neuron activities in the adult, while Kiss2 plays an additional role in stimulating embryonic development of the trigeminal neuronal population, but is an RFamide that inhibits electrical activity of hypophysiotropic GnRH3 neurons in the adult.
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Affiliation(s)
- Yali Zhao
- Department of Physiology, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, United States of America
| | - Meng-Chin A. Lin
- Department of Physiology, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, United States of America
| | - Allan Mock
- Department of Physiology, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, United States of America
| | - Ming Yang
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai, China
| | - Nancy L. Wayne
- Department of Physiology, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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Schaffer AE, Eggens VRC, Caglayan AO, Reuter MS, Scott E, Coufal NG, Silhavy JL, Xue Y, Kayserili H, Yasuno K, Rosti RO, Abdellateef M, Caglar C, Kasher PR, Cazemier JL, Weterman MA, Cantagrel V, Cai N, Zweier C, Altunoglu U, Satkin NB, Aktar F, Tuysuz B, Yalcinkaya C, Caksen H, Bilguvar K, Fu XD, Trotta CR, Gabriel S, Reis A, Gunel M, Baas F, Gleeson JG. CLP1 founder mutation links tRNA splicing and maturation to cerebellar development and neurodegeneration. Cell 2014; 157:651-63. [PMID: 24766810 DOI: 10.1016/j.cell.2014.03.049] [Citation(s) in RCA: 194] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 01/07/2014] [Accepted: 03/21/2014] [Indexed: 12/20/2022]
Abstract
Neurodegenerative diseases can occur so early as to affect neurodevelopment. From a cohort of more than 2,000 consanguineous families with childhood neurological disease, we identified a founder mutation in four independent pedigrees in cleavage and polyadenylation factor I subunit 1 (CLP1). CLP1 is a multifunctional kinase implicated in tRNA, mRNA, and siRNA maturation. Kinase activity of the CLP1 mutant protein was defective, and the tRNA endonuclease complex (TSEN) was destabilized, resulting in impaired pre-tRNA cleavage. Germline clp1 null zebrafish showed cerebellar neurodegeneration that was rescued by wild-type, but not mutant, human CLP1 expression. Patient-derived induced neurons displayed both depletion of mature tRNAs and accumulation of unspliced pre-tRNAs. Transfection of partially processed tRNA fragments into patient cells exacerbated an oxidative stress-induced reduction in cell survival. Our data link tRNA maturation to neuronal development and neurodegeneration through defective CLP1 function in humans.
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Affiliation(s)
- Ashleigh E Schaffer
- Neurogenetics Laboratory, Howard Hughes Medical Institute, Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Veerle R C Eggens
- Department of Genome Analysis, Academic Medical Center, Meibergdreef 9,1105AZ Amsterdam, the Netherlands
| | - Ahmet Okay Caglayan
- Yale Program on Neurogenetics, Departments of Neurosurgery, Neurobiology, and Genetics, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Miriam S Reuter
- Institute of Human Genetics, Universität Erlangen-Nürnberg, Schwabachanlage 10, Erlangen 91054, Germany
| | - Eric Scott
- Neurogenetics Laboratory, Howard Hughes Medical Institute, Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Nicole G Coufal
- Neurogenetics Laboratory, Howard Hughes Medical Institute, Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jennifer L Silhavy
- Neurogenetics Laboratory, Howard Hughes Medical Institute, Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yuanchao Xue
- Cellular Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Hulya Kayserili
- Medical Genetics Department, Istanbul Medical Faculty, Istanbul University, Millet Caddesi, 34093 Fatih/Istanbul, Turkey
| | - Katsuhito Yasuno
- Yale Program on Neurogenetics, Departments of Neurosurgery, Neurobiology, and Genetics, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Rasim Ozgur Rosti
- Neurogenetics Laboratory, Howard Hughes Medical Institute, Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Mostafa Abdellateef
- Neurogenetics Laboratory, Howard Hughes Medical Institute, Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Caner Caglar
- Yale Program on Neurogenetics, Departments of Neurosurgery, Neurobiology, and Genetics, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Paul R Kasher
- Department of Genome Analysis, Academic Medical Center, Meibergdreef 9,1105AZ Amsterdam, the Netherlands
| | - J Leonie Cazemier
- Department of Genome Analysis, Academic Medical Center, Meibergdreef 9,1105AZ Amsterdam, the Netherlands
| | - Marian A Weterman
- Department of Genome Analysis, Academic Medical Center, Meibergdreef 9,1105AZ Amsterdam, the Netherlands
| | - Vincent Cantagrel
- Neurogenetics Laboratory, Howard Hughes Medical Institute, Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA; Institut IMAGINE, INSERM U1163, Faculté Paris-Descartes, 75015 Paris, France
| | - Na Cai
- Neurogenetics Laboratory, Howard Hughes Medical Institute, Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Christiane Zweier
- Institute of Human Genetics, Universität Erlangen-Nürnberg, Schwabachanlage 10, Erlangen 91054, Germany
| | - Umut Altunoglu
- Medical Genetics Department, Istanbul Medical Faculty, Istanbul University, Millet Caddesi, 34093 Fatih/Istanbul, Turkey
| | - N Bilge Satkin
- Medical Genetics Department, Istanbul Medical Faculty, Istanbul University, Millet Caddesi, 34093 Fatih/Istanbul, Turkey
| | - Fesih Aktar
- Department of Pediatrics, Diyarbakir State Hospital, 21100 Diyarbakir, Turkey
| | - Beyhan Tuysuz
- Department of Pediatric Genetics, Cerrahpaşa Medical School, Istanbul University, 34098 Istanbul, Turkey
| | - Cengiz Yalcinkaya
- Department of Neurology, Division of Child Neurology, Cerrahpaşa Medical School, Istanbul University, 34098 Istanbul, Turkey
| | - Huseyin Caksen
- Department of Pediatrics, Meram Medical School, Necmettin Erbakan University, 42080 Konya, Turkey
| | - Kaya Bilguvar
- Yale Program on Neurogenetics, Departments of Neurosurgery, Neurobiology, and Genetics, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Xiang-Dong Fu
- Cellular Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | | | - Stacey Gabriel
- Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - André Reis
- Institute of Human Genetics, Universität Erlangen-Nürnberg, Schwabachanlage 10, Erlangen 91054, Germany
| | - Murat Gunel
- Yale Program on Neurogenetics, Departments of Neurosurgery, Neurobiology, and Genetics, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Frank Baas
- Department of Genome Analysis, Academic Medical Center, Meibergdreef 9,1105AZ Amsterdam, the Netherlands
| | - Joseph G Gleeson
- Neurogenetics Laboratory, Howard Hughes Medical Institute, Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA.
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Patten SA, Armstrong GAB, Lissouba A, Kabashi E, Parker JA, Drapeau P. Fishing for causes and cures of motor neuron disorders. Dis Model Mech 2014; 7:799-809. [PMID: 24973750 PMCID: PMC4073270 DOI: 10.1242/dmm.015719] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Motor neuron disorders (MNDs) are a clinically heterogeneous group of neurological diseases characterized by progressive degeneration of motor neurons, and share some common pathological pathways. Despite remarkable advances in our understanding of these diseases, no curative treatment for MNDs exists. To better understand the pathogenesis of MNDs and to help develop new treatments, the establishment of animal models that can be studied efficiently and thoroughly is paramount. The zebrafish (Danio rerio) is increasingly becoming a valuable model for studying human diseases and in screening for potential therapeutics. In this Review, we highlight recent progress in using zebrafish to study the pathology of the most common MNDs: spinal muscular atrophy (SMA), amyotrophic lateral sclerosis (ALS) and hereditary spastic paraplegia (HSP). These studies indicate the power of zebrafish as a model to study the consequences of disease-related genes, because zebrafish homologues of human genes have conserved functions with respect to the aetiology of MNDs. Zebrafish also complement other animal models for the study of pathological mechanisms of MNDs and are particularly advantageous for the screening of compounds with therapeutic potential. We present an overview of their potential usefulness in MND drug discovery, which is just beginning and holds much promise for future therapeutic development.
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Affiliation(s)
- Shunmoogum A Patten
- Department of Neuroscience, FRQS Groupe de Recherche sur le Système Nerveux Central and CRCHUM, University of Montréal, Montréal, QC H3A 2B4, Canada
| | - Gary A B Armstrong
- Department of Neuroscience, FRQS Groupe de Recherche sur le Système Nerveux Central and CRCHUM, University of Montréal, Montréal, QC H3A 2B4, Canada
| | - Alexandra Lissouba
- Department of Neuroscience, FRQS Groupe de Recherche sur le Système Nerveux Central and CRCHUM, University of Montréal, Montréal, QC H3A 2B4, Canada
| | - Edor Kabashi
- Institut du Cerveau et de la Moelle Épinière, Centre de Recherche, CHU Pitié-Salpétrière, 75013 Paris, France
| | - J Alex Parker
- Department of Neuroscience, FRQS Groupe de Recherche sur le Système Nerveux Central and CRCHUM, University of Montréal, Montréal, QC H3A 2B4, Canada
| | - Pierre Drapeau
- Department of Neuroscience, FRQS Groupe de Recherche sur le Système Nerveux Central and CRCHUM, University of Montréal, Montréal, QC H3A 2B4, Canada.
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Kang PB, Gooch CL, McDermott MP, Darras BT, Finkel RS, Yang ML, Sproule DM, Chung WK, Kaufmann P, de Vivo DC. The motor neuron response to SMN1 deficiency in spinal muscular atrophy. Muscle Nerve 2014; 49:636-44. [PMID: 23893312 DOI: 10.1002/mus.23967] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 07/09/2013] [Accepted: 07/12/2013] [Indexed: 12/23/2022]
Abstract
INTRODUCTION The purpose of this study was to measure and analyze motor unit number estimation (MUNE) values longitudinally in spinal muscular atrophy (SMA). METHODS Sixty-two children with SMA types 2 and 3 were observed prospectively for up to 42 months. Longitudinal electrophysiological data were collected, including compound motor action potential (CMAP), single motor unit action potential (SMUP), and MUNE. RESULTS Significant motor neuron loss and compensatory collateral reinnervation were noted at baseline. Over time, there was a significant mean increase in MUNE (4.92 units/year, P = 0.009), a mean decrease in SMUP amplitude (-6.32 μV/year, P = 0.10), and stable CMAP amplitude. CONCLUSIONS The unexpected longitudinal results differ from findings in amyotrophic lateral sclerosis studies, perhaps indicating that compensatory processes in SMA involve new motor unit development. A better understanding of the mechanisms of motor unit decline and compensation in SMA is important for assessing novel therapeutic strategies and for providing key insights into disease pathophysiology.
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Affiliation(s)
- Peter B Kang
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, Massachusetts, 02115, USA
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Babin PJ, Goizet C, Raldúa D. Zebrafish models of human motor neuron diseases: advantages and limitations. Prog Neurobiol 2014; 118:36-58. [PMID: 24705136 DOI: 10.1016/j.pneurobio.2014.03.001] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 03/11/2014] [Accepted: 03/14/2014] [Indexed: 01/08/2023]
Abstract
Motor neuron diseases (MNDs) are an etiologically heterogeneous group of disorders of neurodegenerative origin, which result in degeneration of lower (LMNs) and/or upper motor neurons (UMNs). Neurodegenerative MNDs include pure hereditary spastic paraplegia (HSP), which involves specific degeneration of UMNs, leading to progressive spasticity of the lower limbs. In contrast, spinal muscular atrophy (SMA) involves the specific degeneration of LMNs, with symmetrical muscle weakness and atrophy. Amyotrophic lateral sclerosis (ALS), the most common adult-onset MND, is characterized by the degeneration of both UMNs and LMNs, leading to progressive muscle weakness, atrophy, and spasticity. A review of the comparative neuroanatomy of the human and zebrafish motor systems showed that, while the zebrafish was a homologous model for LMN disorders, such as SMA, it was only partially relevant in the case of UMN disorders, due to the absence of corticospinal and rubrospinal tracts in its central nervous system. Even considering the limitation of this model to fully reproduce the human UMN disorders, zebrafish offer an excellent alternative vertebrate model for the molecular and genetic dissection of MND mechanisms. Its advantages include the conservation of genome and physiological processes and applicable in vivo tools, including easy imaging, loss or gain of function methods, behavioral tests to examine changes in motor activity, and the ease of simultaneous chemical/drug testing on large numbers of animals. This facilitates the assessment of the environmental origin of MNDs, alone or in combination with genetic traits and putative modifier genes. Positive hits obtained by phenotype-based small-molecule screening using zebrafish may potentially be effective drugs for treatment of human MNDs.
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Affiliation(s)
- Patrick J Babin
- Univ. Bordeaux, Maladies Rares: Génétique et Métabolisme (MRGM), EA 4576, Talence, France.
| | - Cyril Goizet
- Univ. Bordeaux, Maladies Rares: Génétique et Métabolisme (MRGM), EA 4576, Talence, France; CHU Bordeaux, Hôpital Pellegrin, Service de Génétique Médicale, Bordeaux, France
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Abstract
PURPOSE OF REVIEW Spinal muscular atrophy (SMA) is a pediatric neuromuscular condition characterized by progressive proximal muscle weakness. It is one of the most common genetic causes of infant mortality across different races and is caused by mutation of the survival of motor neuron 1 (SMN1) gene on chromosome 5q13. RECENT FINDINGS To date, there have been many therapeutics developments for SMA targeting various potential pathways such as increasing SMN gene expression, enhancing SMN2 exon 7 inclusion, neuroprotection, cell replacement, and gene therapy. SUMMARY Although SMA remains an incurable disease to date, recent advances in the field of basic and translational research have enhanced our understanding of the pathogenesis of the disease and opened new possibilities for therapeutic intervention. This article reviews and highlights past and current translational research on SMA therapeutics.
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Affiliation(s)
- Priyamvada Singh
- aDepartment of Neurology, Boston Children's Hospital and Harvard Medical School, Boston bSaint Vincent Hospital, Worcester, USA *Priyamvada Singh and Wendy K.M. Liew contributed equally to the writing of this article
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Lyon AN, Pineda RH, Hao LT, Kudryashova E, Kudryashov DS, Beattie CE. Calcium binding is essential for plastin 3 function in Smn-deficient motoneurons. Hum Mol Genet 2013; 23:1990-2004. [PMID: 24271012 DOI: 10.1093/hmg/ddt595] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The actin-binding and bundling protein, plastin 3 (PLS3), was identified as a protective modifier of spinal muscular atrophy (SMA) in some patient populations and as a disease modifier in animal models of SMA. How it functions in this process, however, is not known. Because PLS3 is an actin-binding/bundling protein, we hypothesized it would likely act via modification of the actin cytoskeleton in axons and neuromuscular junctions to protect motoneurons in SMA. To test this, we examined the ability of other known actin cytoskeleton organizing proteins to modify motor axon outgrowth phenotypes in an smn morphant zebrafish model of SMA. While PLS3 can fully compensate for low levels of smn, cofilin 1, profilin 2 and α-actinin 1 did not affect smn morphant motor axon outgrowth. To determine how PLS3 functions in SMA, we generated deletion constructs of conserved PLS3 structural domains. The EF hands were essential for PLS3 rescue of smn morphant phenotypes, and mutation of the Ca(2+)-binding residues within the EF hands resulted in a complete loss of PLS3 rescue. These results indicate that Ca(2+) regulation is essential for the function of PLS3 in motor axons. Remarkably, PLS3 mutants lacking both actin-binding domains were still able to rescue motor axons in smn morphants, although not as well as full-length PLS3. Therefore, PLS3 function in this process may have an actin-independent component.
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Affiliation(s)
- Alison N Lyon
- Department of Neuroscience, The Ohio State University, 132 Rightmire Hall, 1060 Carmack Rd, Columbus, OH 43210, USA and
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Da Costa MMJ, Allen CE, Higginbottom A, Ramesh T, Shaw PJ, McDermott CJ. A new zebrafish model produced by TILLING of SOD1-related amyotrophic lateral sclerosis replicates key features of the disease and represents a tool for in vivo therapeutic screening. Dis Model Mech 2013; 7:73-81. [PMID: 24092880 PMCID: PMC3882050 DOI: 10.1242/dmm.012013] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Mutations in the superoxide dismutase gene (SOD1) are one cause of familial amyotrophic lateral sclerosis [ALS; also known as motor neuron disease (MND)] in humans. ALS is a relentlessly progressive neurodegenerative disease and, to date, there are no neuroprotective therapies with significant impact on the disease course. Current transgenic murine models of the disease, which overexpress mutant SOD1, have so far been ineffective in the identification of new therapies beneficial in the human disease. Because the human and the zebrafish (Danio rerio) SOD1 protein share 76% identity, TILLING ('targeting induced local lesions in genomes') was carried out in collaboration with the Sanger Institute in order to identify mutations in the zebrafish sod1 gene. A T70I mutant zebrafish line was characterised using oxidative stress assays, neuromuscular junction (NMJ) analysis and motor function studies. The T70I sod1 zebrafish model offers the advantage over current murine models of expressing the mutant Sod1 protein at a physiological level, as occurs in humans with ALS. The T70I sod1 zebrafish demonstrates key features of ALS: an early NMJ phenotype, susceptibility to oxidative stress and an adult-onset motor neuron disease phenotype. We have demonstrated that the susceptibility of T70I sod1 embryos to oxidative stress can be used in a drug screening assay, to identify compounds that merit further investigation as potential therapies for ALS.
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Affiliation(s)
- Marc M J Da Costa
- Sheffield Institute for Translational Neuroscience, The University of Sheffield, Sheffield S10 2HQ, UK
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Gassman A, Hao LT, Bhoite L, Bradford CL, Chien CB, Beattie CE, Manfredi JP. Small molecule suppressors of Drosophila kinesin deficiency rescue motor axon development in a zebrafish model of spinal muscular atrophy. PLoS One 2013; 8:e74325. [PMID: 24023935 PMCID: PMC3762770 DOI: 10.1371/journal.pone.0074325] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 07/31/2013] [Indexed: 12/15/2022] Open
Abstract
Proximal spinal muscular atrophy (SMA) is the most common inherited motor neuropathy and the leading hereditary cause of infant mortality. Currently there is no effective treatment for the disease, reflecting a need for pharmacologic interventions that restore performance of dysfunctional motor neurons or suppress the consequences of their dysfunction. In a series of assays relevant to motor neuron biology, we explored the activities of a collection of tetrahydroindoles that were reported to alter the metabolism of amyloid precursor protein (APP). In Drosophila larvae the compounds suppressed aberrant larval locomotion due to mutations in the Khc and Klc genes, which respectively encode the heavy and light chains of kinesin-1. A representative compound of this class also suppressed the appearance of axonal swellings (alternatively termed axonal spheroids or neuritic beads) in the segmental nerves of the kinesin-deficient Drosophila larvae. Given the importance of kinesin-dependent transport for extension and maintenance of axons and their growth cones, three members of the class were tested for neurotrophic effects on isolated rat spinal motor neurons. Each compound stimulated neurite outgrowth. In addition, consistent with SMA being an axonopathy of motor neurons, the three axonotrophic compounds rescued motor axon development in a zebrafish model of SMA. The results introduce a collection of small molecules as pharmacologic suppressors of SMA-associated phenotypes and nominate specific members of the collection for development as candidate SMA therapeutics. More generally, the results reinforce the perception of SMA as an axonopathy and suggest novel approaches to treating the disease.
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Affiliation(s)
- Andrew Gassman
- Sera Prognostics, Inc., Salt Lake City, Utah, United States of America
| | - Le T. Hao
- Department of Neuroscience, The Ohio State University, Columbus, Ohio, United States of America
| | - Leena Bhoite
- Technology Commercialization Office, University of Utah, Salt Lake City, Utah, United States of America
| | - Chad L. Bradford
- Sera Prognostics, Inc., Salt Lake City, Utah, United States of America
| | - Chi-Bin Chien
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah, United States of America
| | - Christine E. Beattie
- Department of Neuroscience, The Ohio State University, Columbus, Ohio, United States of America
| | - John P. Manfredi
- Sfida BioLogic, Inc., Salt Lake City, Utah, United States of America
- * E-mail:
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Chapman AL, Bennett EJ, Ramesh TM, De Vos KJ, Grierson AJ. Axonal Transport Defects in a Mitofusin 2 Loss of Function Model of Charcot-Marie-Tooth Disease in Zebrafish. PLoS One 2013; 8:e67276. [PMID: 23840650 PMCID: PMC3694133 DOI: 10.1371/journal.pone.0067276] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 05/16/2013] [Indexed: 02/06/2023] Open
Abstract
Charcot-Marie-Tooth disease (CMT) represents a group of neurodegenerative disorders typically characterised by demyelination (CMT1) or distal axon degeneration (CMT2) of motor and sensory neurons. The majority of CMT2 cases are caused by mutations in mitofusin 2 (MFN2); an essential gene encoding a protein responsible for fusion of the mitochondrial outer membrane. The mechanism of action of MFN2 mutations is still not fully resolved. To investigate a role for loss of Mfn2 function in disease we investigated an ENU-induced nonsense mutation in zebrafish MFN2 and characterised the phenotype of these fish at the whole organism, pathological, and subcellular level. We show that unlike mice, loss of MFN2 function in zebrafish leads to an adult onset, progressive phenotype with predominant symptoms of motor dysfunction similar to CMT2. Mutant zebrafish show progressive loss of swimming associated with alterations at the neuro-muscular junction. At the cellular level, we provide direct evidence that mitochondrial transport along axons is perturbed in Mfn2 mutant zebrafish, suggesting that this is a key mechanism of disease in CMT. The progressive phenotype and pathology suggest that zebrafish will be useful for further investigating the disease mechanism and potential treatment of axonal forms of CMT. Our findings support the idea that MFN2 mutation status should be investigated in patients presenting with early-onset recessively inherited axonal CMT.
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Affiliation(s)
- Anna L. Chapman
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Ellen J. Bennett
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Tennore M. Ramesh
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Kurt J. De Vos
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Andrew J. Grierson
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
- Medical Research Council Centre for Developmental and Biomedical Genetics, University of Sheffield, Sheffield, United Kingdom
- * E-mail:
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Huttner IG, Trivedi G, Jacoby A, Mann SA, Vandenberg JI, Fatkin D. A transgenic zebrafish model of a human cardiac sodium channel mutation exhibits bradycardia, conduction-system abnormalities and early death. J Mol Cell Cardiol 2013; 61:123-32. [PMID: 23791817 DOI: 10.1016/j.yjmcc.2013.06.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 06/05/2013] [Accepted: 06/11/2013] [Indexed: 12/11/2022]
Abstract
The recent exponential increase in human genetic studies due to the advances of next generation sequencing has generated unprecedented numbers of new gene variants. Determining which of these are causative of human disease is a major challenge. In-vitro studies and murine models have been used to study inherited cardiac arrhythmias but have several limitations. Zebrafish models provide an attractive alternative for modeling human heart disease due to similarities in cardiac electrophysiology and contraction, together with ease of genetic manipulation, external development and optical transparency. Although zebrafish cardiac mutants and morphants have been widely used to study loss and knockdown of zebrafish gene function, the phenotypic effects of human dominant-negative gene mutations expressed in transgenic zebrafish have not been evaluated. The aim of this study was to generate and characterize a transgenic zebrafish arrhythmia model harboring the pathogenic human cardiac sodium channel mutation SCN5A-D1275N, that has been robustly associated with a range of cardiac phenotypes, including conduction disease, sinus node dysfunction, atrial and ventricular arrhythmias, and dilated cardiomyopathy in humans and in mice. Stable transgenic fish with cardiac expression of human SCN5A were generated using Tol2-mediated transgenesis and cardiac phenotypes were analyzed using video microscopy and ECG. Here we show that transgenic zebrafish expressing the SCN5A-D1275N mutation, but not wild-type SCN5A, exhibit bradycardia, conduction-system abnormalities and premature death. We furthermore show that SCN5A-WT, and to a lesser degree SCN5A-D1275N, are able to compensate the loss of endogenous zebrafish cardiac sodium channels, indicating that the basic pathways, through which SCN5A acts, are conserved in teleosts. This proof-of-principle study suggests that zebrafish may be highly useful in vivo models to differentiate functional from benign human genetic variants in cardiac ion channel genes in a time- and cost-efficient manner. This article is part of a Special Issue entitled "Na(+) Regulation in Cardiac Myocytes".
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Affiliation(s)
- Inken G Huttner
- Molecular Cardiology Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia
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50
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Armstrong GAB, Drapeau P. Loss and gain of FUS function impair neuromuscular synaptic transmission in a genetic model of ALS. Hum Mol Genet 2013; 22:4282-92. [PMID: 23771027 DOI: 10.1093/hmg/ddt278] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) presents clinically in adulthood and is characterized by the loss of motoneurons in the spinal cord and cerebral cortex. Animal models of the disease suggest that significant neuronal abnormalities exist during preclinical stages of the disease. Mutations in the gene fused in sarcoma (FUS) are associated with ALS and cause impairment in motor function in animal models. However, the mechanism of neuromuscular dysfunction underlying pathophysiological deficits causing impairment in locomotor function resulting from mutant FUS expression is unknown. To characterize the cellular pathophysiological defect, we expressed the wild-type human gene (wtFUS) or the ALS-associated mutation R521H (mutFUS) gene in zebrafish larvae and characterized their motor (swimming) activity and function of their neuromuscular junctions (NMJs). Additionally, we tested knockdown of zebrafish fus with an antisense morpholino oligonucleotide (fus AMO). Expression of either mutFUS or knockdown of fus resulted in impaired motor activity and reduced NMJ synaptic fidelity with reduced quantal transmission. Primary motoneurons expressing mutFUS were found to be more excitable. These impairments in neuronal function could be partially restored in fus AMO larvae also expressing wtFUS (fus AMO+wtFUS) but not mutFUS (fus AMO+mutFUS). These results show that both a loss and gain of FUS function result in defective presynaptic function at the NMJ.
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Affiliation(s)
- Gary A B Armstrong
- Department of Pathology and Cell Biology and Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, QC, Canada H3C 3J7
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