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Rhymes ER, Simkin RL, Qu J, Villarroel-Campos D, Surana S, Tong Y, Shapiro R, Burgess RW, Yang XL, Schiavo G, Sleigh JN. Boosting BDNF in muscle rescues impaired axonal transport in a mouse model of DI-CMTC peripheral neuropathy. Neurobiol Dis 2024; 195:106501. [PMID: 38583640 DOI: 10.1016/j.nbd.2024.106501] [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] [Received: 03/12/2024] [Revised: 04/04/2024] [Accepted: 04/04/2024] [Indexed: 04/09/2024] Open
Abstract
Charcot-Marie-Tooth disease (CMT) is a genetic peripheral neuropathy caused by mutations in many functionally diverse genes. The aminoacyl-tRNA synthetase (ARS) enzymes, which transfer amino acids to partner tRNAs for protein synthesis, represent the largest protein family genetically linked to CMT aetiology, suggesting pathomechanistic commonalities. Dominant intermediate CMT type C (DI-CMTC) is caused by YARS1 mutations driving a toxic gain-of-function in the encoded tyrosyl-tRNA synthetase (TyrRS), which is mediated by exposure of consensus neomorphic surfaces through conformational changes of the mutant protein. In this study, we first showed that human DI-CMTC-causing TyrRSE196K mis-interacts with the extracellular domain of the BDNF receptor TrkB, an aberrant association we have previously characterised for several mutant glycyl-tRNA synthetases linked to CMT type 2D (CMT2D). We then performed temporal neuromuscular assessments of YarsE196K mice modelling DI-CMT. We determined that YarsE196K homozygotes display a selective, age-dependent impairment in in vivo axonal transport of neurotrophin-containing signalling endosomes, phenocopying CMT2D mice. This impairment is replicated by injection of recombinant TyrRSE196K, but not TyrRSWT, into muscles of wild-type mice. Augmenting BDNF in DI-CMTC muscles, through injection of recombinant protein or muscle-specific gene therapy, resulted in complete axonal transport correction. Therefore, this work identifies a non-cell autonomous pathomechanism common to ARS-related neuropathies, and highlights the potential of boosting BDNF levels in muscles as a therapeutic strategy.
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Affiliation(s)
- Elena R Rhymes
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Rebecca L Simkin
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Ji Qu
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - David Villarroel-Campos
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK; UK Dementia Research Institute at University College London, London WC1N 3BG, UK
| | - Sunaina Surana
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK; UK Dementia Research Institute at University College London, London WC1N 3BG, UK
| | - Yao Tong
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Ryan Shapiro
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | | | - Xiang-Lei Yang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Giampietro Schiavo
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK; UK Dementia Research Institute at University College London, London WC1N 3BG, UK
| | - James N Sleigh
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK; UK Dementia Research Institute at University College London, London WC1N 3BG, UK.
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Rhymes ER, Simkin RL, Qu J, Villarroel-Campos D, Surana S, Tong Y, Shapiro R, Burgess RW, Yang XL, Schiavo G, Sleigh JN. Boosting BDNF in muscle rescues impaired axonal transport in a mouse model of DI-CMTC peripheral neuropathy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.04.09.536152. [PMID: 38559020 PMCID: PMC10979848 DOI: 10.1101/2023.04.09.536152] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Charcot-Marie-Tooth disease (CMT) is a genetic peripheral neuropathy caused by mutations in many functionally diverse genes. The aminoacyl-tRNA synthetase (ARS) enzymes, which transfer amino acids to partner tRNAs for protein synthesis, represent the largest protein family genetically linked to CMT aetiology, suggesting pathomechanistic commonalities. Dominant intermediate CMT type C (DI-CMTC) is caused by YARS1 mutations driving a toxic gain-of-function in the encoded tyrosyl-tRNA synthetase (TyrRS), which is mediated by exposure of consensus neomorphic surfaces through conformational changes of the mutant protein. In this study, we first showed that human DI-CMTC-causing TyrRSE196K mis-interacts with the extracellular domain of the BDNF receptor TrkB, an aberrant association we have previously characterised for several mutant glycyl-tRNA synthetases linked to CMT type 2D (CMT2D). We then performed temporal neuromuscular assessments of YarsE196K mice modelling DI-CMT. We determined that YarsE196K homozygotes display a selective, age-dependent impairment in in vivo axonal transport of neurotrophin-containing signalling endosomes, phenocopying CMT2D mice. This impairment is replicated by injection of recombinant TyrRSE196K, but not TyrRSWT, into muscles of wild-type mice. Augmenting BDNF in DI-CMTC muscles, through injection of recombinant protein or muscle-specific gene therapy, resulted in complete axonal transport correction. Therefore, this work identifies a non-cell autonomous pathomechanism common to ARS-related neuropathies, and highlights the potential of boosting BDNF levels in muscles as a therapeutic strategy.
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Affiliation(s)
- Elena R. Rhymes
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Rebecca L. Simkin
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Ji Qu
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - David Villarroel-Campos
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
- UK Dementia Research Institute at University College London, London WC1N 3BG, UK
| | - Sunaina Surana
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
- UK Dementia Research Institute at University College London, London WC1N 3BG, UK
| | - Yao Tong
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Ryan Shapiro
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | | | - Xiang-Lei Yang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Giampietro Schiavo
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
- UK Dementia Research Institute at University College London, London WC1N 3BG, UK
| | - James N. Sleigh
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
- UK Dementia Research Institute at University College London, London WC1N 3BG, UK
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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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Martinez JL, Piciw JG, Crockett M, Sorci IA, Makwana N, Sirois CL, Giffin-Rao Y, Bhattacharyya A. Transcriptional consequences of trisomy 21 on neural induction. Front Cell Neurosci 2024; 18:1341141. [PMID: 38357436 PMCID: PMC10865501 DOI: 10.3389/fncel.2024.1341141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Accepted: 01/08/2024] [Indexed: 02/16/2024] Open
Abstract
Introduction Down syndrome, caused by trisomy 21, is a complex developmental disorder associated with intellectual disability and reduced growth of multiple organs. Structural pathologies are present at birth, reflecting embryonic origins. A fundamental unanswered question is how an extra copy of human chromosome 21 contributes to organ-specific pathologies that characterize individuals with Down syndrome, and, relevant to the hallmark intellectual disability in Down syndrome, how trisomy 21 affects neural development. We tested the hypothesis that trisomy 21 exerts effects on human neural development as early as neural induction. Methods Bulk RNA sequencing was performed on isogenic trisomy 21 and euploid human induced pluripotent stem cells (iPSCs) at successive stages of neural induction: embryoid bodies at Day 6, early neuroectoderm at Day 10, and differentiated neuroectoderm at Day 17. Results Gene expression analysis revealed over 1,300 differentially expressed genes in trisomy 21 cells along the differentiation pathway compared to euploid controls. Less than 5% of the gene expression changes included upregulated chromosome 21 encoded genes at every timepoint. Genes involved in specific growth factor signaling pathways (WNT and Notch), metabolism (including oxidative stress), and extracellular matrix were altered in trisomy 21 cells. Further analysis uncovered heterochronic expression of genes. Conclusion Trisomy 21 impacts discrete developmental pathways at the earliest stages of neural development. The results suggest that metabolic dysfunction arises early in embryogenesis in trisomy 21 and may affect development and function more broadly.
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Affiliation(s)
- José L. Martinez
- Waisman Center, University of Wisconsin-Madison, Madison, WI, United States
- Cellular and Molecular Biology Graduate Program, University of Wisconsin-Madison, Madison, WI, United States
| | - Jennifer G. Piciw
- Waisman Center, University of Wisconsin-Madison, Madison, WI, United States
- Cellular and Molecular Biology Graduate Program, University of Wisconsin-Madison, Madison, WI, United States
- Medical Scientist Training Program, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
| | - Madeline Crockett
- Waisman Center, University of Wisconsin-Madison, Madison, WI, United States
| | - Isabella A. Sorci
- Waisman Center, University of Wisconsin-Madison, Madison, WI, United States
| | - Nikunj Makwana
- Waisman Center, University of Wisconsin-Madison, Madison, WI, United States
| | - Carissa L. Sirois
- Waisman Center, University of Wisconsin-Madison, Madison, WI, United States
| | | | - Anita Bhattacharyya
- Waisman Center, University of Wisconsin-Madison, Madison, WI, United States
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
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Lee Y, Yeo IS, Kim N, Lee DK, Kim KT, Yoon J, Yi J, Hong YB, Choi BO, Kosodo Y, Kim D, Park J, Song MR. Transcriptional control of motor pool formation and motor circuit connectivity by the LIM-HD protein Isl2. eLife 2023; 12:e84596. [PMID: 37869988 PMCID: PMC10637776 DOI: 10.7554/elife.84596] [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] [Received: 10/31/2022] [Accepted: 10/11/2023] [Indexed: 10/24/2023] Open
Abstract
The fidelity of motor control requires the precise positional arrangement of motor pools and the establishment of synaptic connections between them. During neural development in the spinal cord, motor nerves project to specific target muscles and receive proprioceptive input from these muscles via the sensorimotor circuit. LIM-homeodomain transcription factors are known to play a crucial role in successively restricting specific motor neuronal fates. However, their exact contribution to limb-based motor pools and locomotor circuits has not been fully understood. To address this, we conducted an investigation into the role of Isl2, a LIM-homeodomain transcription factor, in motor pool organization. We found that deletion of Isl2 led to the dispersion of motor pools, primarily affecting the median motor column (MMC) and lateral motor column (LMC) populations. Additionally, hindlimb motor pools lacked Etv4 expression, and we observed reduced terminal axon branching and disorganized neuromuscular junctions in Isl2-deficient mice. Furthermore, we performed transcriptomic analysis on the spinal cords of Isl2-deficient mice and identified a variety of downregulated genes associated with motor neuron (MN) differentiation, axon development, and synapse organization in hindlimb motor pools. As a consequence of these disruptions, sensorimotor connectivity and hindlimb locomotion were impaired in Isl2-deficient mice. Taken together, our findings highlight the critical role of Isl2 in organizing motor pool position and sensorimotor circuits in hindlimb motor pools. This research provides valuable insights into the molecular mechanisms governing motor control and its potential implications for understanding motor-related disorders in humans.
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Affiliation(s)
- Yunjeong Lee
- School of Life Sciences, Gwangju Institute of Science and Technology, Oryong-dong, Buk-guGwangjuRepublic of Korea
| | - In Seo Yeo
- School of Life Sciences, Gwangju Institute of Science and Technology, Oryong-dong, Buk-guGwangjuRepublic of Korea
| | - Namhee Kim
- Fermentation Regulation Technology Research Group, World Institute of KimchiGwangjuRepublic of Korea
| | - Dong-Keun Lee
- School of Life Sciences, Gwangju Institute of Science and Technology, Oryong-dong, Buk-guGwangjuRepublic of Korea
| | - Kyung-Tai Kim
- Jeonbuk Department of Inhalation Research, Korea Institute of ToxicologyJeongeup-siRepublic of Korea
| | - Jiyoung Yoon
- School of Life Sciences, Gwangju Institute of Science and Technology, Oryong-dong, Buk-guGwangjuRepublic of Korea
| | - Jawoon Yi
- School of Life Sciences, Gwangju Institute of Science and Technology, Oryong-dong, Buk-guGwangjuRepublic of Korea
| | - Young Bin Hong
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of MedicineSeoulRepublic of Korea
- Department of Biochemistry, College of Medicine, Dong-A UniversityBusanRepublic of Korea
| | - Byung-Ok Choi
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of MedicineSeoulRepublic of Korea
| | - Yoichi Kosodo
- Korea Brain Research InstituteDaeguRepublic of Korea
| | - Daesoo Kim
- Department of Brain and Cognitive Sciences, Korea Advanced Institute of Science and Technology (KAIST)DaejeonRepublic of Korea
| | - Jihwan Park
- School of Life Sciences, Gwangju Institute of Science and Technology, Oryong-dong, Buk-guGwangjuRepublic of Korea
| | - Mi-Ryoung Song
- School of Life Sciences, Gwangju Institute of Science and Technology, Oryong-dong, Buk-guGwangjuRepublic of Korea
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Sleigh JN, Villarroel-Campos D, Surana S, Wickenden T, Tong Y, Simkin RL, Vargas JNS, Rhymes ER, Tosolini AP, West SJ, Zhang Q, Yang XL, Schiavo G. Boosting peripheral BDNF rescues impaired in vivo axonal transport in CMT2D mice. JCI Insight 2023; 8:e157191. [PMID: 36928301 PMCID: PMC10243821 DOI: 10.1172/jci.insight.157191] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 03/15/2023] [Indexed: 03/18/2023] Open
Abstract
Gain-of-function mutations in the housekeeping gene GARS1, which lead to the expression of toxic versions of glycyl-tRNA synthetase (GlyRS), cause the selective motor and sensory pathology characterizing Charcot-Marie-Tooth disease (CMT). Aberrant interactions between GlyRS mutants and different proteins, including neurotrophin receptor tropomyosin receptor kinase receptor B (TrkB), underlie CMT type 2D (CMT2D); however, our pathomechanistic understanding of this untreatable peripheral neuropathy remains incomplete. Through intravital imaging of the sciatic nerve, we show that CMT2D mice displayed early and persistent disturbances in axonal transport of neurotrophin-containing signaling endosomes in vivo. We discovered that brain-derived neurotrophic factor (BDNF)/TrkB impairments correlated with transport disruption and overall CMT2D neuropathology and that inhibition of this pathway at the nerve-muscle interface perturbed endosome transport in wild-type axons. Accordingly, supplementation of muscles with BDNF, but not other neurotrophins, completely restored physiological axonal transport in neuropathic mice. Together, these findings suggest that selectively targeting muscles with BDNF-boosting therapies could represent a viable therapeutic strategy for CMT2D.
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Affiliation(s)
- James N. Sleigh
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
- UK Dementia Research Institute, University College London (UCL), London, United Kingdom
| | - David Villarroel-Campos
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
| | - Sunaina Surana
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
- UK Dementia Research Institute, University College London (UCL), London, United Kingdom
| | - Tahmina Wickenden
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
| | - Yao Tong
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Rebecca L. Simkin
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
| | - Jose Norberto S. Vargas
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
| | - Elena R. Rhymes
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
| | - Andrew P. Tosolini
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
| | | | - Qian Zhang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Xiang-Lei Yang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Giampietro Schiavo
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
- UK Dementia Research Institute, University College London (UCL), London, United Kingdom
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Faravelli I, Riboldi GM, Rinchetti P, Lotti F. The SMN Complex at the Crossroad between RNA Metabolism and Neurodegeneration. Int J Mol Sci 2023; 24:2247. [PMID: 36768569 PMCID: PMC9917330 DOI: 10.3390/ijms24032247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 01/17/2023] [Accepted: 01/20/2023] [Indexed: 01/24/2023] Open
Abstract
In the cell, RNA exists and functions in a complex with RNA binding proteins (RBPs) that regulate each step of the RNA life cycle from transcription to degradation. Central to this regulation is the role of several molecular chaperones that ensure the correct interactions between RNA and proteins, while aiding the biogenesis of large RNA-protein complexes (ribonucleoproteins or RNPs). Accurate formation of RNPs is fundamentally important to cellular development and function, and its impairment often leads to disease. The survival motor neuron (SMN) protein exemplifies this biological paradigm. SMN is part of a multi-protein complex essential for the biogenesis of various RNPs that function in RNA metabolism. Mutations leading to SMN deficiency cause the neurodegenerative disease spinal muscular atrophy (SMA). A fundamental question in SMA biology is how selective motor system dysfunction results from reduced levels of the ubiquitously expressed SMN protein. Recent clarification of the central role of the SMN complex in RNA metabolism and a thorough characterization of animal models of SMA have significantly advanced our knowledge of the molecular basis of the disease. Here we review the expanding role of SMN in the regulation of gene expression through its multiple functions in RNP biogenesis. We discuss developments in our understanding of SMN activity as a molecular chaperone of RNPs and how disruption of SMN-dependent RNA pathways can contribute to the SMA phenotype.
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Affiliation(s)
- Irene Faravelli
- Department of Stem Cell & Regenerative Biology, Harvard University, Cambridge, MA 02138, USA
- Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology, and Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Giulietta M. Riboldi
- Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology, and Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
- The Marlene and Paolo Fresco Institute for Parkinson’s and Movement Disorders, NYU Langone Health, New York, NY 10017, USA
| | - Paola Rinchetti
- Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology, and Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Francesco Lotti
- Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology, and Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
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8
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Singh J, Patten SA. Modeling neuromuscular diseases in zebrafish. Front Mol Neurosci 2022; 15:1054573. [PMID: 36583079 PMCID: PMC9794147 DOI: 10.3389/fnmol.2022.1054573] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 11/21/2022] [Indexed: 12/15/2022] Open
Abstract
Neuromuscular diseases are a diverse group of conditions that affect the motor system and present some overlapping as well as distinct clinical manifestations. Although individually rare, the combined prevalence of NMDs is similar to Parkinson's. Over the past decade, new genetic mutations have been discovered through whole exome/genome sequencing, but the pathogenesis of most NMDs remains largely unexplored. Little information on the molecular mechanism governing the progression and development of NMDs accounts for the continual failure of therapies in clinical trials. Different aspects of the diseases are typically investigated using different models from cells to animals. Zebrafish emerges as an excellent model for studying genetics and pathogenesis and for developing therapeutic interventions for most NMDs. In this review, we describe the generation of different zebrafish genetic models mimicking NMDs and how they are used for drug discovery and therapy development.
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Affiliation(s)
- Jaskaran Singh
- INRS – Centre Armand Frappier Santé Biotechnologie, Laval, QC, Canada
| | - Shunmoogum A. Patten
- INRS – Centre Armand Frappier Santé Biotechnologie, Laval, QC, Canada,Departement de Neurosciences, Université de Montréal, Montréal, QC, Canada,Centre d'Excellence en Recherche sur les Maladies Orphelines – Fondation Courtois (CERMO-FC), Université du Québec à Montréal (UQAM), Montréal, QC, Canada,*Correspondence: Shunmoogum A. Patten,
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9
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Oprişoreanu AM. Perspective on automated in vivo drug screening using the chodl mutant zebrafish line. Neural Regen Res 2022; 17:2437-2438. [PMID: 35535889 PMCID: PMC9120713 DOI: 10.4103/1673-5374.335795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/31/2021] [Accepted: 09/08/2021] [Indexed: 11/04/2022] Open
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10
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Jia L, Li F, Wei C, Zhu M, Qu Q, Qin W, Tang Y, Shen L, Wang Y, Shen L, Li H, Peng D, Tan L, Luo B, Guo Q, Tang M, Du Y, Zhang J, Zhang J, Lyu J, Li Y, Zhou A, Wang F, Chu C, Song H, Wu L, Zuo X, Han Y, Liang J, Wang Q, Jin H, Wang W, Lü Y, Li F, Zhou Y, Zhang W, Liao Z, Qiu Q, Li Y, Kong C, Li Y, Jiao H, Lu J, Jia J. Prediction of Alzheimer's disease using multi-variants from a Chinese genome-wide association study. Brain 2021; 144:924-937. [PMID: 33188687 PMCID: PMC8041344 DOI: 10.1093/brain/awaa364] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 07/30/2020] [Accepted: 08/14/2020] [Indexed: 12/28/2022] Open
Abstract
Previous genome-wide association studies have identified dozens of susceptibility loci for sporadic Alzheimer’s disease, but few of these loci have been validated in longitudinal cohorts. Establishing predictive models of Alzheimer’s disease based on these novel variants is clinically important for verifying whether they have pathological functions and provide a useful tool for screening of disease risk. In the current study, we performed a two-stage genome-wide association study of 3913 patients with Alzheimer’s disease and 7593 controls and identified four novel variants (rs3777215, rs6859823, rs234434, and rs2255835; Pcombined = 3.07 × 10−19, 2.49 × 10−23, 1.35 × 10−67, and 4.81 × 10−9, respectively) as well as nine variants in the apolipoprotein E region with genome-wide significance (P < 5.0 × 10−8). Literature mining suggested that these novel single nucleotide polymorphisms are related to amyloid precursor protein transport and metabolism, antioxidation, and neurogenesis. Based on their possible roles in the development of Alzheimer’s disease, we used different combinations of these variants and the apolipoprotein E status and successively built 11 predictive models. The predictive models include relatively few single nucleotide polymorphisms useful for clinical practice, in which the maximum number was 13 and the minimum was only four. These predictive models were all significant and their peak of area under the curve reached 0.73 both in the first and second stages. Finally, these models were validated using a separate longitudinal cohort of 5474 individuals. The results showed that individuals carrying risk variants included in the models had a shorter latency and higher incidence of Alzheimer’s disease, suggesting that our models can predict Alzheimer’s disease onset in a population with genetic susceptibility. The effectiveness of the models for predicting Alzheimer’s disease onset confirmed the contributions of these identified variants to disease pathogenesis. In conclusion, this is the first study to validate genome-wide association study-based predictive models for evaluating the risk of Alzheimer’s disease onset in a large Chinese population. The clinical application of these models will be beneficial for individuals harbouring these risk variants, and particularly for young individuals seeking genetic consultation.
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Affiliation(s)
- Longfei Jia
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, China
| | - Fangyu Li
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, China
| | - Cuibai Wei
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, China
| | - Min Zhu
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, China
| | - Qiumin Qu
- Department of Neurology, The First Affiliated Hospital of Xi'an Jiaotong University, Shaanxi, China
| | - Wei Qin
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, China
| | - Yi Tang
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, China
| | - Luxi Shen
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, China
| | - Yanjiang Wang
- Department of Neurology and Center for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Lu Shen
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Honglei Li
- Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Zhejiang, China
| | - Dantao Peng
- Department of Neurology, China-Japan Friendship Hospital, Beijing, China
| | - Lan Tan
- Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Shandong, China
| | - Benyan Luo
- Department of Neurology, The First Affiliated Hospital, Zhejiang University, Zhejiang, China
| | - Qihao Guo
- Department of Gerontology, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Muni Tang
- Department of Geriatrics, Guangzhou Huiai Hospital, Affiliated Hospital of Guangzhou Medical College, Guangzhou, China
| | - Yifeng Du
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong University, Shandong, China
| | - Jiewen Zhang
- Department of Neurology, Henan Provincial People's Hospital, Zhengzhou University People's Hospital, Henan, China
| | - Junjian Zhang
- Department of Neurology, Zhongnan Hospital, Wuhan University, Hubei, China
| | - Jihui Lyu
- Center for Cognitive Disorders, Beijing Geriatric Hospital, Beijing, China
| | - Ying Li
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, China
| | - Aihong Zhou
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, China
| | - Fen Wang
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, China
| | - Changbiao Chu
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, China
| | - Haiqing Song
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, China
| | - Liyong Wu
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, China
| | - Xiumei Zuo
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, China
| | - Yue Han
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, China
| | - Junhua Liang
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, China
| | - Qi Wang
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, China
| | - Hongmei Jin
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, China
| | - Wei Wang
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, China
| | - Yang Lü
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Fang Li
- Department of Geriatric, Fuxing Hospital, Capital Medical University, Beijing, China
| | - Yuying Zhou
- Department of Neurology, Tianjin Huanhu Hospital, Tianjin, China
| | - Wei Zhang
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,Center for Cognitive Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Zhengluan Liao
- Department of Psychiatry, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang, China
| | - Qiongqiong Qiu
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, China
| | - Yan Li
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, China
| | - Chaojun Kong
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, China
| | - Yan Li
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, China
| | - Haishan Jiao
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, China
| | - Jie Lu
- Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, China.,Department of Nuclear Medicine, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Jianping Jia
- Innovation Center for Neurological Disorders and Department of Neurology, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, Beijing, China.,Beijing Key Laboratory of Geriatric Cognitive Disorders, Beijing, China.,Clinical Center for Neurodegenerative Disease and Memory Impairment, Capital Medical University, Beijing, China.,Center of Alzheimer's Disease, Beijing Institute for Brain Disorders, Beijing, China
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11
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Spinal muscular atrophy: From approved therapies to future therapeutic targets for personalized medicine. CELL REPORTS MEDICINE 2021; 2:100346. [PMID: 34337562 PMCID: PMC8324491 DOI: 10.1016/j.xcrm.2021.100346] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Spinal muscular atrophy (SMA) is a devastating childhood motor neuron disease that, in the most severe cases and when left untreated, leads to death within the first two years of life. Recent therapeutic advances have given hope to families and patients by compensating for the deficiency in survival motor neuron (SMN) protein via gene therapy or other genetic manipulation. However, it is now apparent that none of these therapies will cure SMA alone. In this review, we discuss the three currently licensed therapies for SMA, briefly highlighting their respective advantages and disadvantages, before considering alternative approaches to increasing SMN protein levels. We then explore recent preclinical research that is identifying and targeting dysregulated pathways secondary to, or independent of, SMN deficiency that may provide adjunctive opportunities for SMA. These additional therapies are likely to be key for the development of treatments that are effective across the lifespan of SMA patients. Three licensed SMA therapies increase SMN levels, but are not a cure Other strategies to increase SMN levels are still under development Alternatives target the correction of dysregulated pathways following SMN loss Ultimately, a range of therapies may allow for a tailored treatment
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12
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Van Alstyne M, Tattoli I, Delestree N, Recinos Y, Workman E, Shihabuddin LS, Zhang C, Mentis GZ, Pellizzoni L. Gain of toxic function by long-term AAV9-mediated SMN overexpression in the sensorimotor circuit. Nat Neurosci 2021; 24:930-940. [PMID: 33795885 PMCID: PMC8254787 DOI: 10.1038/s41593-021-00827-3] [Citation(s) in RCA: 92] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 02/24/2021] [Indexed: 02/01/2023]
Abstract
The neurodegenerative disease spinal muscular atrophy (SMA) is caused by deficiency in the survival motor neuron (SMN) protein. Currently approved SMA treatments aim to restore SMN, but the potential for SMN expression beyond physiological levels is a unique feature of adeno-associated virus serotype 9 (AAV9)-SMN gene therapy. Here, we show that long-term AAV9-mediated SMN overexpression in mouse models induces dose-dependent, late-onset motor dysfunction associated with loss of proprioceptive synapses and neurodegeneration. Mechanistically, aggregation of overexpressed SMN in the cytoplasm of motor circuit neurons sequesters components of small nuclear ribonucleoproteins, leading to splicing dysregulation and widespread transcriptome abnormalities with prominent signatures of neuroinflammation and the innate immune response. Thus, long-term SMN overexpression interferes with RNA regulation and triggers SMA-like pathogenic events through toxic gain-of-function mechanisms. These unanticipated, SMN-dependent and neuron-specific liabilities warrant caution on the long-term safety of treating individuals with SMA with AAV9-SMN and the risks of uncontrolled protein expression by gene therapy.
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Affiliation(s)
- Meaghan Van Alstyne
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, 10032,Department of Pathology and Cell Biology, Columbia University, New York, NY, 10032,Department of Neurology, Columbia University, New York, NY, 10032
| | - Ivan Tattoli
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, 10032,Department of Pathology and Cell Biology, Columbia University, New York, NY, 10032
| | - Nicolas Delestree
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, 10032,Department of Pathology and Cell Biology, Columbia University, New York, NY, 10032,Department of Neurology, Columbia University, New York, NY, 10032
| | - Yocelyn Recinos
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, 10032,Department of Systems Biology, Columbia University, New York, NY 10032,Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032
| | - Eileen Workman
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, 10032,Department of Pathology and Cell Biology, Columbia University, New York, NY, 10032
| | | | - Chaolin Zhang
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, 10032,Department of Systems Biology, Columbia University, New York, NY 10032,Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032
| | - George Z. Mentis
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, 10032,Department of Pathology and Cell Biology, Columbia University, New York, NY, 10032,Department of Neurology, Columbia University, New York, NY, 10032
| | - Livio Pellizzoni
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, 10032,Department of Pathology and Cell Biology, Columbia University, New York, NY, 10032,Department of Neurology, Columbia University, New York, NY, 10032,Address correspondence to: Livio Pellizzoni, Center for Motor Neuron Biology and Disease, Department of Pathology and Cell Biology, Columbia University, 630 West 168TH Street, New York, NY, 10032. Phone: +1 212-305-3046;
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13
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Oprişoreanu AM, Smith HL, Krix S, Chaytow H, Carragher NO, Gillingwater TH, Becker CG, Becker T. Automated in vivo drug screen in zebrafish identifies synapse-stabilising drugs with relevance to spinal muscular atrophy. Dis Model Mech 2021; 14:259422. [PMID: 33973627 PMCID: PMC8106959 DOI: 10.1242/dmm.047761] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Accepted: 03/10/2021] [Indexed: 12/14/2022] Open
Abstract
Synapses are particularly vulnerable in many neurodegenerative diseases and often the first to degenerate, for example in the motor neuron disease spinal muscular atrophy (SMA). Compounds that can counteract synaptic destabilisation are rare. Here, we describe an automated screening paradigm in zebrafish for small-molecule compounds that stabilize the neuromuscular synapse in vivo. We make use of a mutant for the axonal C-type lectin chondrolectin (chodl), one of the main genes dysregulated in SMA. In chodl-/- mutants, neuromuscular synapses that are formed at the first synaptic site by growing axons are not fully mature, causing axons to stall, thereby impeding further axon growth beyond that synaptic site. This makes axon length a convenient read-out for synapse stability. We screened 982 small-molecule compounds in chodl chodl-/- mutants and found four that strongly rescued motor axon length. Aberrant presynaptic neuromuscular synapse morphology was also corrected. The most-effective compound, the adenosine uptake inhibitor drug dipyridamole, also rescued axon growth defects in the UBA1-dependent zebrafish model of SMA. Hence, we describe an automated screening pipeline that can detect compounds with relevance to SMA. This versatile platform can be used for drug and genetic screens, with wider relevance to synapse formation and stabilisation.
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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
| | - Hannah L Smith
- Centre for Discovery Brain Sciences, University of Edinburgh, The Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB
| | - Sophia Krix
- Centre for Discovery Brain Sciences, University of Edinburgh, The Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB
| | - Helena Chaytow
- Centre for Discovery Brain Sciences, University of Edinburgh, The Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, EH16 4SB Edinburgh, UK
| | - Neil O Carragher
- Cancer Research UK Edinburgh Centre, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, EH4 2XR Edinburgh, UK
| | - Thomas H Gillingwater
- Centre for Discovery Brain Sciences, University of Edinburgh, The Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, EH16 4SB Edinburgh, UK
| | - Catherina G Becker
- Centre for Discovery Brain Sciences, University of Edinburgh, The Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, EH16 4SB Edinburgh, UK
| | - Thomas Becker
- Centre for Discovery Brain Sciences, University of Edinburgh, The Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB
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14
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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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15
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Nusinersen ameliorates motor function and prevents motoneuron Cajal body disassembly and abnormal poly(A) RNA distribution in a SMA mouse model. Sci Rep 2020; 10:10738. [PMID: 32612161 PMCID: PMC7330045 DOI: 10.1038/s41598-020-67569-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 06/08/2020] [Indexed: 11/09/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a devastating autosomal recessive neuromuscular disease characterized by degeneration of spinal cord alpha motor neurons (αMNs). SMA is caused by the homozygous deletion or mutation of the survival motor neuron 1 (SMN1) gene, resulting in reduced expression of SMN protein, which leads to αMN degeneration and muscle atrophy. The majority of transcripts of a second gene (SMN2) generate an alternative spliced isoform that lacks exon 7 and produces a truncated nonfunctional form of SMN. A major function of SMN is the biogenesis of spliceosomal snRNPs, which are essential components of the pre-mRNA splicing machinery, the spliceosome. In recent years, new potential therapies have been developed to increase SMN levels, including treatment with antisense oligonucleotides (ASOs). The ASO-nusinersen (Spinraza) promotes the inclusion of exon 7 in SMN2 transcripts and notably enhances the production of full-length SMN in mouse models of SMA. In this work, we used the intracerebroventricular injection of nusinersen in the SMN∆7 mouse model of SMA to evaluate the effects of this ASO on the behavior of Cajal bodies (CBs), nuclear structures involved in spliceosomal snRNP biogenesis, and the cellular distribution of polyadenylated mRNAs in αMNs. The administration of nusinersen at postnatal day (P) 1 normalized SMN expression in the spinal cord but not in skeletal muscle, rescued the growth curve and improved motor behavior at P12 (late symptomatic stage). Importantly, this ASO recovered the number of canonical CBs in MNs, significantly reduced the abnormal accumulation of polyadenylated RNAs in nuclear granules, and normalized the expression of the pre-mRNAs encoding chondrolectin and choline acetyltransferase, two key factors for αMN homeostasis. We propose that the splicing modulatory function of nusinersen in SMA αMN is mediated by the rescue of CB biogenesis, resulting in enhanced polyadenylated pre-mRNA transcription and splicing and nuclear export of mature mRNAs for translation. Our results support that the selective restoration of SMN expression in the spinal cord has a beneficial impact not only on αMNs but also on skeletal myofibers. However, the rescue of SMN expression in muscle appears to be necessary for the complete recovery of motor function.
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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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Gao X, Xu J, Chen H, Xue D, Pan W, Zhou C, Ma YC, Ma L. Defective Expression of Mitochondrial, Vacuolar H +-ATPase and Histone Genes in a C. elegans Model of SMA. Front Genet 2019; 10:410. [PMID: 31130987 PMCID: PMC6509145 DOI: 10.3389/fgene.2019.00410] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Accepted: 04/15/2019] [Indexed: 12/16/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a severe motor neuron degenerative disease caused by loss-of-function mutations in the survival motor neuron gene SMN1. It is widely posited that defective gene expression underlies SMA. However, the identities of these affected genes remain to be elucidated. By analyzing the transcriptome of a Caenorhabditis elegans SMA model at the pre-symptomatic stage, we found that the expression of numerous nuclear encoded mitochondrial genes and vacuolar H+-ATPase genes was significantly down-regulated, while that of histone genes was significantly up-regulated. We previously showed that the uaf-1 gene, encoding key splicing factor U2AF large subunit, could affect the behavior and lifespan of smn-1 mutants. Here, we found that smn-1 and uaf-1 interact to affect the recognition of 3′ and 5′ splice sites in a gene-specific manner. Altogether, our results suggest a functional interaction between smn-1 and uaf-1 in affecting RNA splicing and a potential effect of smn-1 on the expression of mitochondrial and histone genes.
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Affiliation(s)
- Xiaoyang Gao
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Jing Xu
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Hao Chen
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Dingwu Xue
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Wenju Pan
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Chuanman Zhou
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Yongchao C Ma
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, United States
| | - Long Ma
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China.,Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, China.,Hunan Key Laboratory of Animal Models for Human Diseases, School of Life Sciences, Central South University, Changsha, China
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18
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Custer SK, Astroski JW, Li HX, Androphy EJ. Interaction between alpha-COP and SMN ameliorates disease phenotype in a mouse model of spinal muscular atrophy. Biochem Biophys Res Commun 2019; 514:530-537. [PMID: 31060774 DOI: 10.1016/j.bbrc.2019.04.176] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 04/26/2019] [Indexed: 11/25/2022]
Abstract
We report that expression of the α-COP protein rescues disease phenotype in a severe mouse model of Spinal Muscular Atrophy (SMA). Lentiviral particles expressing α-COP were injected directly into the testes of genetically pure mouse strain of interest resulting in infection of the spermatagonial stem cells. α-COP was stably expressed in brain, skeletal muscle, and spinal cord without altering SMN protein levels. SMA mice transgenic for α-COP live significantly longer than their non-transgenic littermates, and showed increased body mass and normal muscle morphology at postnatal day 15. We previously reported that binding between SMN and α-COP is required for restoration of neurite outgrowth in cells lacking SMN, and we report similar finding here. Lentiviral-mediated transgenic expression of SMN where the dilysine domain in exon 2b was mutated was not able to rescue the SMA phenotype despite robust expression of the mutant SMN protein in brain, muscle and spinal cord. These results demonstrate that α-COP is a validated modifier of SMA disease phenotype in a mammalian, vertebrate model and is a potential target for development of future SMN-independent therapeutic interventions.
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Affiliation(s)
- Sara K Custer
- Indiana University School of Medicine, Dermatology, Indianapolis, IN, USA.
| | - Jacob W Astroski
- Indiana University School of Medicine, Dermatology, Indianapolis, IN, USA
| | - Hong Xia Li
- Indiana University School of Medicine, Dermatology, Indianapolis, IN, USA
| | - Elliot J Androphy
- Indiana University School of Medicine, Dermatology, Indianapolis, IN, USA
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19
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Manuel M, Zytnicki D. Molecular and electrophysiological properties of mouse motoneuron and motor unit subtypes. CURRENT OPINION IN PHYSIOLOGY 2018; 8:23-29. [PMID: 32551406 DOI: 10.1016/j.cophys.2018.11.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The field of motoneuron and motor unit physiology in mammals has deeply evolved the last decade thanks to the parallel development of mouse genetics and transcriptomic analysis and of in vivo mouse preparations that allow intracellular electrophysiological recordings of motoneurons. We review the efforts made to investigate the electrophysiological properties of the different functional subtypes of mouse motoneurons, to decipher the mosaic of molecular markers specifically expressed in each subtype, and to elucidate which of those factors drive the identity of motoneurons.
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Affiliation(s)
- Marin Manuel
- Center for Neurophysics, Physiology and Pathology, Paris Descartes University, CNRS UMR 8119, Paris, France
| | - Daniel Zytnicki
- Center for Neurophysics, Physiology and Pathology, Paris Descartes University, CNRS UMR 8119, Paris, France
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20
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Chaytow H, Huang YT, Gillingwater TH, Faller KME. The role of survival motor neuron protein (SMN) in protein homeostasis. Cell Mol Life Sci 2018; 75:3877-3894. [PMID: 29872871 PMCID: PMC6182345 DOI: 10.1007/s00018-018-2849-1] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 05/30/2018] [Accepted: 05/31/2018] [Indexed: 12/11/2022]
Abstract
Ever since loss of survival motor neuron (SMN) protein was identified as the direct cause of the childhood inherited neurodegenerative disorder spinal muscular atrophy, significant efforts have been made to reveal the molecular functions of this ubiquitously expressed protein. Resulting research demonstrated that SMN plays important roles in multiple fundamental cellular homeostatic pathways, including a well-characterised role in the assembly of the spliceosome and biogenesis of ribonucleoproteins. More recent studies have shown that SMN is also involved in other housekeeping processes, including mRNA trafficking and local translation, cytoskeletal dynamics, endocytosis and autophagy. Moreover, SMN has been shown to influence mitochondria and bioenergetic pathways as well as regulate function of the ubiquitin-proteasome system. In this review, we summarise these diverse functions of SMN, confirming its key role in maintenance of the homeostatic environment of the cell.
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Affiliation(s)
- Helena Chaytow
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Yu-Ting Huang
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Thomas H Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK.
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK.
| | - Kiterie M E Faller
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
- Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK
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21
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Beattie CE, Kolb SJ. Spinal muscular atrophy: Selective motor neuron loss and global defect in the assembly of ribonucleoproteins. Brain Res 2018; 1693:92-97. [DOI: 10.1016/j.brainres.2018.02.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 02/10/2018] [Accepted: 02/15/2018] [Indexed: 12/13/2022]
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22
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Maretina MA, Zheleznyakova GY, Lanko KM, Egorova AA, Baranov VS, Kiselev AV. Molecular Factors Involved in Spinal Muscular Atrophy Pathways as Possible Disease-modifying Candidates. Curr Genomics 2018; 19:339-355. [PMID: 30065610 PMCID: PMC6030859 DOI: 10.2174/1389202919666180101154916] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 12/15/2017] [Accepted: 12/18/2017] [Indexed: 01/07/2023] Open
Abstract
Spinal Muscular Atrophy (SMA) is a neuromuscular disorder caused by mutations in the SMN1 gene. Being a monogenic disease, it is characterized by high clinical heterogeneity. Variations in penetrance and severity of symptoms, as well as clinical discrepancies between affected family members can result from modifier genes influence on disease manifestation. SMN2 gene copy number is known to be the main phenotype modifier and there is growing evidence of additional factors contributing to SMA severity. Potential modifiers of spinal muscular atrophy can be found among the wide variety of different factors, such as multiple proteins interacting with SMN or promoting motor neuron survival, epigenetic modifications, transcriptional or splicing factors influencing SMN2 expression. Study of these factors enables to reveal mechanisms underlying SMA pathology and can have pronounced clinical application.
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Affiliation(s)
- Marianna A. Maretina
- D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya line, 3, Saint Petersburg199034, Russia
- Saint Petersburg State University, Universitetskaya emb. 7/9, 199034Saint Petersburg, Russia
| | - Galina Y. Zheleznyakova
- Department of Clinical Neuroscience, Karolinska Institutet, Karolinska Universitetssjukhuset, 171 76 Stockholm, Sweden
| | - Kristina M. Lanko
- Saint Petersburg State Institute of Technology, Moskovsky prospect, 26, Saint Petersburg190013, Russia
| | - Anna A. Egorova
- D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya line, 3, Saint Petersburg199034, Russia
| | - Vladislav S. Baranov
- D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya line, 3, Saint Petersburg199034, Russia
- Saint Petersburg State University, Universitetskaya emb. 7/9, 199034Saint Petersburg, Russia
| | - Anton V. Kiselev
- D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya line, 3, Saint Petersburg199034, Russia
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23
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Narcís JO, Tapia O, Tarabal O, Piedrafita L, Calderó J, Berciano MT, Lafarga M. Accumulation of poly(A) RNA in nuclear granules enriched in Sam68 in motor neurons from the SMNΔ7 mouse model of SMA. Sci Rep 2018; 8:9646. [PMID: 29941967 PMCID: PMC6018117 DOI: 10.1038/s41598-018-27821-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 06/11/2018] [Indexed: 01/07/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a severe motor neuron (MN) disease caused by the deletion or mutation of the survival motor neuron 1 (SMN1) gene, which results in reduced levels of the SMN protein and the selective degeneration of lower MNs. The best-known function of SMN is the biogenesis of spliceosomal snRNPs, the major components of the pre-mRNA splicing machinery. Therefore, SMN deficiency in SMA leads to widespread splicing abnormalities. We used the SMN∆7 mouse model of SMA to investigate the cellular reorganization of polyadenylated mRNAs associated with the splicing dysfunction in MNs. We demonstrate that SMN deficiency induced the abnormal nuclear accumulation in euchromatin domains of poly(A) RNA granules (PARGs) enriched in the splicing regulator Sam68. However, these granules lacked other RNA-binding proteins, such as TDP43, PABPN1, hnRNPA12B, REF and Y14, which are essential for mRNA processing and nuclear export. These effects were accompanied by changes in the alternative splicing of the Sam68-dependent Bcl-x and Nrnx1 genes, as well as changes in the relative accumulation of the intron-containing Chat, Chodl, Myh9 and Myh14 mRNAs, which are all important for MN functions. PARG-containing MNs were observed at presymptomatic SMA stage, increasing their number during the symptomatic stage. Moreover, the massive accumulations of poly(A) RNA granules in MNs was accompanied by the cytoplasmic depletion of polyadenylated mRNAs for their translation. We suggest that the SMN-dependent abnormal accumulation of polyadenylated mRNAs and Sam68 in PARGs reflects a severe dysfunction of both mRNA processing and translation, which could contribute to SMA pathogenesis.
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Affiliation(s)
- J Oriol Narcís
- Department of Anatomy and Cell Biology and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)", University of Cantabria-IDIVAL, Santander, Spain
| | - Olga Tapia
- Department of Anatomy and Cell Biology and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)", University of Cantabria-IDIVAL, Santander, Spain
| | - Olga Tarabal
- Department of Experimental Medicine, School of Medicine, University of Lleida and "Institut de Recerca Biomèdica de Lleida" (IRBLLEIDA), Lleida, Spain
| | - Lídia Piedrafita
- Department of Experimental Medicine, School of Medicine, University of Lleida and "Institut de Recerca Biomèdica de Lleida" (IRBLLEIDA), Lleida, Spain
| | - Jordi Calderó
- Department of Experimental Medicine, School of Medicine, University of Lleida and "Institut de Recerca Biomèdica de Lleida" (IRBLLEIDA), Lleida, Spain
| | - Maria T Berciano
- Department of Anatomy and Cell Biology and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)", University of Cantabria-IDIVAL, Santander, Spain.,Department of Molecular Biology and CIBERNED, University of Cantabria-IDIVAL, Santander, Spain
| | - Miguel Lafarga
- Department of Anatomy and Cell Biology and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)", University of Cantabria-IDIVAL, Santander, Spain.
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24
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Pletto D, Capra S, Finardi A, Colciaghi F, Nobili P, Battaglia GS, Locatelli D, Cagnoli C. Axon outgrowth and neuronal differentiation defects after a-SMN and FL-SMN silencing in primary hippocampal cultures. PLoS One 2018; 13:e0199105. [PMID: 29902268 PMCID: PMC6001960 DOI: 10.1371/journal.pone.0199105] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 05/31/2018] [Indexed: 12/30/2022] Open
Abstract
Spinal Muscular Atrophy (SMA) is a severe autosomal recessive disease characterized by selective motor neuron degeneration, caused by disruptions of the Survival of Motor Neuron 1 (Smn1) gene. The main product of SMN1 is the full-length SMN protein (FL-SMN), that plays an established role in mRNA splicing. FL-SMN is also involved in neurite outgrowth and axonal transport. A shorter SMN isoform, axonal-SMN or a-SMN, displays a more specific axonal localization and has remarkable axonogenic properties in NSC-34. Introduction of known SMA mutations into the a-SMN transcript leads to impairment of axon growth and morphological defects similar to those observed in SMA patients and animal models. Although there is increasing evidence for the relevance of SMN axonal functions in SMA pathogenesis, the specific contributions of FL-SMN and a-SMN are not known yet. This work aimed to analyze the differential roles of FL-SMN and a-SMN in axon outgrowth and in neuronal homeostasis during differentiation of neurons into a mature phenotype. We employed primary cultures of hippocampal neurons as a well-defined model of polarization and differentiation. By analyzing subcellular localization, we showed that a-SMN is preferentially localized in the growing axonal compartment. By specifically silencing FL-SMN or a-SMN proteins, we demonstrated that both proteins play a role in axon growth, as their selective down-regulation reduces axon length without affecting dendritic arborization. a-SMN silencing, and in minor extent FL-SMN silencing, resulted in the growth of multi-neuritic neurons, impaired in the differentiation process of selecting a single axon out of multiple neurites. In these neurons, neurites often display mixed axonal and dendritic markers and abnormal distribution of the axonal initial segment protein Ankirin G, suggesting loss of neuronal polarity. Our results indicate that a-SMN and FL-SMN are needed for neuronal polarization and organization of axonal and dendritic compartments, processes that are fundamental for neuronal function and survival.
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Affiliation(s)
- Daniela Pletto
- Molecular Neuroanatomy and Pathogenesis Unit, Neurology VII—Clinical and Experimental Epileptology Unit, Foundation IRCCS Neurological Institute “C. Besta”, Milano, Italy
| | - Silvia Capra
- Molecular Neuroanatomy and Pathogenesis Unit, Neurology VII—Clinical and Experimental Epileptology Unit, Foundation IRCCS Neurological Institute “C. Besta”, Milano, Italy
| | - Adele Finardi
- Molecular Neuroanatomy and Pathogenesis Unit, Neurology VII—Clinical and Experimental Epileptology Unit, Foundation IRCCS Neurological Institute “C. Besta”, Milano, Italy
| | - Francesca Colciaghi
- Molecular Neuroanatomy and Pathogenesis Unit, Neurology VII—Clinical and Experimental Epileptology Unit, Foundation IRCCS Neurological Institute “C. Besta”, Milano, Italy
| | - Paola Nobili
- Molecular Neuroanatomy and Pathogenesis Unit, Neurology VII—Clinical and Experimental Epileptology Unit, Foundation IRCCS Neurological Institute “C. Besta”, Milano, Italy
| | - Giorgio Stefano Battaglia
- Molecular Neuroanatomy and Pathogenesis Unit, Neurology VII—Clinical and Experimental Epileptology Unit, Foundation IRCCS Neurological Institute “C. Besta”, Milano, Italy
| | - Denise Locatelli
- Molecular Neuroanatomy and Pathogenesis Unit, Neurology VII—Clinical and Experimental Epileptology Unit, Foundation IRCCS Neurological Institute “C. Besta”, Milano, Italy
| | - Cinzia Cagnoli
- Molecular Neuroanatomy and Pathogenesis Unit, Neurology VII—Clinical and Experimental Epileptology Unit, Foundation IRCCS Neurological Institute “C. Besta”, Milano, Italy
- * E-mail:
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25
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Bowerman M, Becker CG, Yáñez-Muñoz RJ, Ning K, Wood MJA, Gillingwater TH, Talbot K. Therapeutic strategies for spinal muscular atrophy: SMN and beyond. Dis Model Mech 2018; 10:943-954. [PMID: 28768735 PMCID: PMC5560066 DOI: 10.1242/dmm.030148] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a devastating neuromuscular disorder characterized by loss of motor neurons and muscle atrophy, generally presenting in childhood. SMA is caused by low levels of the survival motor neuron protein (SMN) due to inactivating mutations in the encoding gene SMN1. A second duplicated gene, SMN2, produces very little but sufficient functional protein for survival. Therapeutic strategies to increase SMN are in clinical trials, and the first SMN2-directed antisense oligonucleotide (ASO) therapy has recently been licensed. However, several factors suggest that complementary strategies may be needed for the long-term maintenance of neuromuscular and other functions in SMA patients. Pre-clinical SMA models demonstrate that the requirement for SMN protein is highest when the structural connections of the neuromuscular system are being established, from late fetal life throughout infancy. Augmenting SMN may not address the slow neurodegenerative process underlying progressive functional decline beyond childhood in less severe types of SMA. Furthermore, individuals receiving SMN-based treatments may be vulnerable to delayed symptoms if rescue of the neuromuscular system is incomplete. Finally, a large number of older patients living with SMA do not fulfill the present criteria for inclusion in gene therapy and ASO clinical trials, and may not benefit from SMN-inducing treatments. Therefore, a comprehensive whole-lifespan approach to SMA therapy is required that includes both SMN-dependent and SMN-independent strategies that treat the CNS and periphery. Here, we review the range of non-SMN pathways implicated in SMA pathophysiology and discuss how various model systems can serve as valuable tools for SMA drug discovery. Summary: Translational research for spinal muscular atrophy (SMA) should address the development of non-CNS and survival motor neuron (SMN)-independent therapeutic approaches to complement and enhance the benefits of CNS-directed and SMN-dependent therapies.
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Affiliation(s)
- Melissa Bowerman
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | - Catherina G Becker
- Euan MacDonald Centre for Motor Neurone Disease Research and Centre for Neuroregeneration, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Rafael J Yáñez-Muñoz
- AGCTlab.org, Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway, University of London, Egham Hill, Egham, Surrey TW20 0EX, UK
| | - Ke Ning
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield S10 2HQ, UK
| | - Matthew J A Wood
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | - Thomas H Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research and Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Kevin Talbot
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
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26
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Reznikov LR, Meyerholz DK, Abou Alaiwa M, Kuan SP, Liao YSJ, Bormann NL, Bair TB, Price M, Stoltz DA, Welsh MJ. The vagal ganglia transcriptome identifies candidate therapeutics for airway hyperreactivity. Am J Physiol Lung Cell Mol Physiol 2018; 315:L133-L148. [PMID: 29631359 PMCID: PMC6139658 DOI: 10.1152/ajplung.00557.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Mainstay therapeutics are ineffective in some people with asthma, suggesting a need for additional agents. In the current study, we used vagal ganglia transcriptome profiling and connectivity mapping to identify compounds beneficial for alleviating airway hyperreactivity (AHR). As a comparison, we also used previously published transcriptome data from sensitized mouse lungs and human asthmatic endobronchial biopsies. All transcriptomes revealed agents beneficial for mitigating AHR; however, only the vagal ganglia transcriptome identified agents used clinically to treat asthma (flunisolide, isoetarine). We also tested one compound identified by vagal ganglia transcriptome profiling that had not previously been linked to asthma and found that it had bronchodilator effects in both mouse and pig airways. These data suggest that transcriptome profiling of the vagal ganglia might be a novel strategy to identify potential asthma therapeutics.
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Affiliation(s)
- Leah R Reznikov
- Department of Physiological Sciences, University of Florida , Gainesville, Florida
| | | | - Mahmoud Abou Alaiwa
- Department of Internal Medicine, University of Iowa , Iowa City, Iowa.,Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa
| | - Shin-Ping Kuan
- Department of Physiological Sciences, University of Florida , Gainesville, Florida
| | - Yan-Shin J Liao
- Department of Physiological Sciences, University of Florida , Gainesville, Florida
| | | | - Thomas B Bair
- Iowa Institute of Human Genetics, University of Iowa , Iowa City, Iowa
| | - Margaret Price
- Department of Internal Medicine, University of Iowa , Iowa City, Iowa.,Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa
| | - David A Stoltz
- Department of Internal Medicine, University of Iowa , Iowa City, Iowa.,Molecular Physiology and Biophysics, University of Iowa , Iowa City, Iowa.,Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa.,Department of Biomedical Engineering, College of Engineering, University of Iowa , Iowa City, Iowa
| | - Michael J Welsh
- Department of Internal Medicine, University of Iowa , Iowa City, Iowa.,Molecular Physiology and Biophysics, University of Iowa , Iowa City, Iowa.,Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City, Iowa.,Howard Hughes Medical Institute, University of Iowa , Iowa City, Iowa
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27
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Martínez-Silva MDL, Imhoff-Manuel RD, Sharma A, Heckman CJ, Shneider NA, Roselli F, Zytnicki D, Manuel M. Hypoexcitability precedes denervation in the large fast-contracting motor units in two unrelated mouse models of ALS. eLife 2018; 7:30955. [PMID: 29580378 PMCID: PMC5922970 DOI: 10.7554/elife.30955] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 03/14/2018] [Indexed: 12/17/2022] Open
Abstract
Hyperexcitability has been suggested to contribute to motoneuron degeneration in amyotrophic lateral sclerosis (ALS). If this is so, and given that the physiological type of a motor unit determines the relative susceptibility of its motoneuron in ALS, then one would expect the most vulnerable motoneurons to display the strongest hyperexcitability prior to their degeneration, whereas the less vulnerable should display a moderate hyperexcitability, if any. We tested this hypothesis in vivo in two unrelated ALS mouse models by correlating the electrical properties of motoneurons with their physiological types, identified based on their motor unit contractile properties. We found that, far from being hyperexcitable, the most vulnerable motoneurons become unable to fire repetitively despite the fact that their neuromuscular junctions were still functional. Disease markers confirm that this loss of function is an early sign of degeneration. Our results indicate that intrinsic hyperexcitability is unlikely to be the cause of motoneuron degeneration. Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease, is a fatal disorder of the nervous system. Early symptoms include muscle weakness, unsteadiness and slurred speech. These symptoms arise because the neurons that control muscles – the motoneurons – lose their ability to make the muscles contract. Eventually, the muscles become paralyzed, with more and more muscles affected over time. Most patients die within a few years of diagnosis when the disease destroys the muscles that control breathing. Muscles are made up of muscle fibers. Each motoneuron controls a bundle of muscle fibers, and the motoneuron and its muscle fibers together make up a motor unit. A single muscle contains hundreds of motor units. These consist of several different types, which differ in how many muscle fibers they contain, how fast those muscle fibers can contract, and how fatigable the muscle fibers are. In ALS, motoneurons become detached from their muscle fibers, causing motor units to break down. But what triggers this process? One long-standing idea is that motoneurons begin to respond excessively to commands from the brain and spinal cord. In other words, they become hyperexcitable, which ultimately leads to their death. But some more recent studies of ALS suggest the opposite, namely that motoneurons become less active, or hypoexcitable. To distinguish between these possibilities, Martinez-Silva et al. took advantage of the fact that different types of motor unit break down at different rates in ALS. Large motor units containing fast-contracting muscle fibers break down before smaller motor units. By measuring the activity of motor units in two mouse models of ALS, Martinez-Silva et al. showed that large motoneurons are hypoexcitable. In other words, the motoneurons that are most vulnerable to ALS respond too little to commands from the nervous system, rather than too much. Studies of specific proteins inside the cells confirmed that hypoexcitable motoneurons are further along in the disease process than other motoneurons. Hypoexcitability is thus a key player in the ALS disease process. Developing drugs to target this hypoexcitability may be a promising strategy for the future of this condition.
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Affiliation(s)
| | - Rebecca D Imhoff-Manuel
- Centre de Neurophysique, Physiologie et Pathologie, CNRS, Université Paris Descartes, Paris, France
| | - Aarti Sharma
- Center for Motor Neuron Biology and Disease, Department of Neurology, Columbia University, New York, United States
| | - C J Heckman
- Department of Physiology, Northwestern University, Feinberg School of Medicine, Chicago, United States.,Department of Physical Medicine and Rehabilitation, Northwestern University, Feinberg School of Medicine, Chicago, United States.,Department of Physical Therapy and Human Movement Science, Northwestern University, Feinberg School of Medicine, Chicago, United States
| | - Neil A Shneider
- Center for Motor Neuron Biology and Disease, Department of Neurology, Columbia University, New York, United States
| | | | - Daniel Zytnicki
- Centre de Neurophysique, Physiologie et Pathologie, CNRS, Université Paris Descartes, Paris, France
| | - Marin Manuel
- Centre de Neurophysique, Physiologie et Pathologie, CNRS, Université Paris Descartes, Paris, France.,Department of Physiology, Northwestern University, Feinberg School of Medicine, Chicago, United States
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28
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Grice SJ, Sleigh JN, Zameel Cader M. Plexin-Semaphorin Signaling Modifies Neuromuscular Defects in a Drosophila Model of Peripheral Neuropathy. Front Mol Neurosci 2018. [PMID: 29520219 PMCID: PMC5827687 DOI: 10.3389/fnmol.2018.00055] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Dominant mutations in GARS, encoding the ubiquitous enzyme glycyl-tRNA synthetase (GlyRS), cause peripheral nerve degeneration and Charcot-Marie-Tooth disease type 2D (CMT2D). This genetic disorder exemplifies a recurring paradigm in neurodegeneration, in which mutations in essential genes cause selective degeneration of the nervous system. Recent evidence suggests that the mechanism underlying CMT2D involves extracellular neomorphic binding of mutant GlyRS to neuronally-expressed proteins. Consistent with this, our previous studies indicate a non-cell autonomous mechanism, whereby mutant GlyRS is secreted and interacts with the neuromuscular junction (NMJ). In this Drosophila model for CMT2D, we have previously shown that mutant gars expression decreases viability and larval motor function, and causes a concurrent build-up of mutant GlyRS at the larval neuromuscular presynapse. Here, we report additional phenotypes that closely mimic the axonal branching defects of Drosophila plexin transmembrane receptor mutants, implying interference of plexin signaling in gars mutants. Individual dosage reduction of two Drosophila Plexins, plexin A (plexA) and B (plexB) enhances and represses the viability and larval motor defects caused by mutant GlyRS, respectively. However, we find plexB levels, but not plexA levels, modify mutant GlyRS association with the presynaptic membrane. Furthermore, increasing availability of the plexB ligand, Semaphorin-2a (Sema2a), alleviates the pathology and the build-up of mutant GlyRS, suggesting competition for plexB binding may be occurring between these two ligands. This toxic gain-of-function and subversion of neurodevelopmental processes indicate that signaling pathways governing axonal guidance could be integral to neuropathology and may underlie the non-cell autonomous CMT2D mechanism.
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Affiliation(s)
- Stuart J Grice
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - James N Sleigh
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
| | - M Zameel Cader
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.,MRC Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
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Small-molecule flunarizine increases SMN protein in nuclear Cajal bodies and motor function in a mouse model of spinal muscular atrophy. Sci Rep 2018; 8:2075. [PMID: 29391529 PMCID: PMC5794986 DOI: 10.1038/s41598-018-20219-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 01/16/2018] [Indexed: 02/07/2023] Open
Abstract
The hereditary neurodegenerative disorder spinal muscular atrophy (SMA) is characterized by the loss of spinal cord motor neurons and skeletal muscle atrophy. SMA is caused by mutations of the survival motor neuron (SMN) gene leading to a decrease in SMN protein levels. The SMN deficiency alters nuclear body formation and whether it can contribute to the disease remains unclear. Here we screen a series of small-molecules on SMA patient fibroblasts and identify flunarizine that accumulates SMN into Cajal bodies, the nuclear bodies important for the spliceosomal small nuclear RNA (snRNA)-ribonucleoprotein biogenesis. Using histochemistry, real-time RT-PCR and behavioural analyses in a mouse model of SMA, we show that along with the accumulation of SMN into Cajal bodies of spinal cord motor neurons, flunarizine treatment modulates the relative abundance of specific spliceosomal snRNAs in a tissue-dependent manner and can improve the synaptic connections and survival of spinal cord motor neurons. The treatment also protects skeletal muscles from cell death and atrophy, raises the neuromuscular junction maturation and prolongs life span by as much as 40 percent (p < 0.001). Our findings provide a functional link between flunarizine and SMA pathology, highlighting the potential benefits of flunarizine in a novel therapeutic perspective against neurodegenerative diseases.
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30
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Tosolini AP, Sleigh JN. Motor Neuron Gene Therapy: Lessons from Spinal Muscular Atrophy for Amyotrophic Lateral Sclerosis. Front Mol Neurosci 2017; 10:405. [PMID: 29270111 PMCID: PMC5725447 DOI: 10.3389/fnmol.2017.00405] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 11/21/2017] [Indexed: 12/11/2022] Open
Abstract
Spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS) are severe nervous system diseases characterized by the degeneration of lower motor neurons. They share a number of additional pathological, cellular, and genetic parallels suggesting that mechanistic and clinical insights into one disorder may have value for the other. While there are currently no clinical ALS gene therapies, the splice-switching antisense oligonucleotide, nusinersen, was recently approved for SMA. This milestone was achieved through extensive pre-clinical research and patient trials, which together have spawned fundamental insights into motor neuron gene therapy. We have thus tried to distil key information garnered from SMA research, in the hope that it may stimulate a more directed approach to ALS gene therapy. Not only must the type of therapeutic (e.g., antisense oligonucleotide vs. viral vector) be sensibly selected, but considerable thought must be applied to the where, which, what, and when in order to enhance treatment benefit: to where (cell types and tissues) must the drug be delivered and how can this be best achieved? Which perturbed pathways must be corrected and can they be concurrently targeted? What dosing regime and concentration should be used? When should medication be administered? These questions are intuitive, but central to identifying and optimizing a successful gene therapy. Providing definitive solutions to these quandaries will be difficult, but clear thinking about therapeutic testing is necessary if we are to have the best chance of developing viable ALS gene therapies and improving upon early generation SMA treatments.
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Affiliation(s)
- Andrew P Tosolini
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
| | - James N Sleigh
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
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31
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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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32
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Bertelli L, Nardo GD, Cazzato S, Ricci G, Pession A. Free-Aspire: A new device for the management of airways clearance in patient with ineffective cough. Pediatr Rep 2017; 9:7270. [PMID: 29081932 PMCID: PMC5643880 DOI: 10.4081/pr.2017.7270] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2017] [Revised: 07/17/2017] [Accepted: 07/17/2017] [Indexed: 11/23/2022] Open
Abstract
A 3-year-old girl with Spinal Muscular Atrophy type I presented with a right pneumonia. On physical examination pulmonary auscultation revealed an asymmetry of breath sounds between the 2 hemithoraces, owing to decreased breath sounds in the right hemithorax. Blood tests were normal. The initial working diagnosis was a suspected area of mucus accumulation. A treatment with Free Aspire was started. Within a few days, the girl was discharged with a normal physical examination and X-ray study result. Spinal Muscular Atrophy is a rare neuromuscular disorder characterized by loss of motor neurons and progressive muscle wasting. Cough in these patients result ineffective. Free-Aspire is an electromedical machine for removing bronchoalveolar secretions. The case show that Free Aspire in patients with ineffective cough and impaired removal of secretions is a safe and effective device for the removal of bronchial secretions and could be an another help in the management of airway clearance.
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Affiliation(s)
- Luca Bertelli
- Department of Pediatrics, University of Bologna, S. Orsola-Malpighi Hospital
| | | | - Salvatore Cazzato
- Department of Mother and Child Health, Salesi Children's Hospital, Ancona, Italy
| | - Giampaolo Ricci
- Department of Pediatrics, University of Bologna, S. Orsola-Malpighi Hospital
| | - Andrea Pession
- Department of Pediatrics, University of Bologna, S. Orsola-Malpighi Hospital
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33
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Neuropilin 1 sequestration by neuropathogenic mutant glycyl-tRNA synthetase is permissive to vascular homeostasis. Sci Rep 2017; 7:9216. [PMID: 28835631 PMCID: PMC5569042 DOI: 10.1038/s41598-017-10005-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 07/27/2017] [Indexed: 12/11/2022] Open
Abstract
The mechanism by which dominantly inherited mutations in the housekeeping gene GARS, which encodes glycyl-tRNA synthetase (GlyRS), mediate selective peripheral nerve toxicity resulting in Charcot-Marie-Tooth disease type 2D (CMT2D) is still largely unresolved. The transmembrane receptor protein neuropilin 1 (Nrp1) was recently identified as an aberrant extracellular binding partner of mutant GlyRS. Formation of the Nrp1/mutant GlyRS complex antagonises Nrp1 interaction with one of its main natural ligands, vascular endothelial growth factor-A (VEGF-A), contributing to neurodegeneration. However, reduced extracellular binding of VEGF-A to Nrp1 is known to disrupt post-natal blood vessel development and growth. We therefore analysed the vascular system at early and late symptomatic time points in CMT2D mouse muscles, retina, and sciatic nerve, as well as in embryonic hindbrain. Mutant tissues show no difference in blood vessel diameter, density/growth, and branching from embryonic development to three months, spanning the duration over which numerous sensory and neuromuscular phenotypes manifest. Our findings indicate that mutant GlyRS-mediated disruption of Nrp1/VEGF-A signalling is permissive to maturation and maintenance of the vasculature in CMT2D mice.
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34
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Lanfranco M, Vassallo N, Cauchi RJ. Spinal Muscular Atrophy: From Defective Chaperoning of snRNP Assembly to Neuromuscular Dysfunction. Front Mol Biosci 2017. [PMID: 28642865 PMCID: PMC5463183 DOI: 10.3389/fmolb.2017.00041] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Spinal Muscular Atrophy (SMA) is a neuromuscular disorder that results from decreased levels of the survival motor neuron (SMN) protein. SMN is part of a multiprotein complex that also includes Gemins 2–8 and Unrip. The SMN-Gemins complex cooperates with the protein arginine methyltransferase 5 (PRMT5) complex, whose constituents include WD45, PRMT5 and pICln. Both complexes function as molecular chaperones, interacting with and assisting in the assembly of an Sm protein core onto small nuclear RNAs (snRNAs) to generate small nuclear ribonucleoproteins (snRNPs), which are the operating components of the spliceosome. Molecular and structural studies have refined our knowledge of the key events taking place within the crowded environment of cells and the numerous precautions undertaken to ensure the faithful assembly of snRNPs. Nonetheless, it remains unclear whether a loss of chaperoning in snRNP assembly, considered as a “housekeeping” activity, is responsible for the selective neuromuscular phenotype in SMA. This review thus shines light on in vivo studies that point toward disturbances in snRNP assembly and the consequential transcriptome abnormalities as the primary drivers of the progressive neuromuscular degeneration underpinning the disease. Disruption of U1 snRNP or snRNP assembly factors other than SMN induces phenotypes that mirror aspects of SMN deficiency, and splicing defects, described in numerous SMA models, can lead to a DNA damage and stress response that compromises the survival of the motor system. Restoring the correct chaperoning of snRNP assembly is therefore predicted to enhance the benefit of SMA therapeutic modalities based on augmenting SMN expression.
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Affiliation(s)
- Maia Lanfranco
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of MaltaMsida, Malta.,Center for Molecular Medicine and Biobanking, University of MaltaMsida, Malta.,Institut de Génétique Moléculaire de Montpellier, Center National de la Recherche Scientifique-UMR 5535, Université de MontpellierMontpellier, France
| | - Neville Vassallo
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of MaltaMsida, Malta.,Center for Molecular Medicine and Biobanking, University of MaltaMsida, Malta
| | - Ruben J Cauchi
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of MaltaMsida, Malta.,Center for Molecular Medicine and Biobanking, University of MaltaMsida, Malta
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35
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Christie-Brown V, Mitchell J, Talbot K. The SMA Trust: the role of a disease-focused research charity in developing treatments for SMA. Gene Ther 2017; 24:544-546. [PMID: 28561814 DOI: 10.1038/gt.2017.47] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 05/09/2017] [Accepted: 05/10/2017] [Indexed: 02/04/2023]
Abstract
SMA is a rare hereditary neuromuscular disease that causes weakness and muscle wasting as a result of the loss of spinal motor neurons. In its most severe form, SMA is the commonest genetic cause of death in infants, and children with less severe forms of SMA face the prospect of lifelong disability from progressive muscle wasting, loss of mobility and limb weakness. The initial discovery of the defective gene has been followed by major advances in our understanding of the genetic, cellular and molecular basis of SMA, providing the foundation for a range of approaches to treatment, including gene therapy, antisense oligonucleotide treatments and more traditional drug-based approaches to slow or halt disease progression. The approval by the US Food and Drug Administration (FDA) of Spinraza (nusinersen), the first targeted treatment for spinal muscular atrophy (SMA), is a historic moment. Disease-focused research charities, such as The SMA Trust (UK), continue to have a crucial role in promoting the development of additional treatments for SMA, both by funding translational research and by promoting links between researchers, people living with SMA and other stakeholders, including pharmaceutical companies and healthcare providers.
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36
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Functional interaction between FUS and SMN underlies SMA-like splicing changes in wild-type hFUS mice. Sci Rep 2017; 7:2033. [PMID: 28515487 PMCID: PMC5435706 DOI: 10.1038/s41598-017-02195-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 04/06/2017] [Indexed: 12/18/2022] Open
Abstract
Several of the identified genetic factors in Amyotrophic Lateral Sclerosis (ALS) point to dysfunction in RNA processing as a major pathogenic mechanism. However, whether a precise RNA pathway is particularly affected remains unknown. Evidence suggests that FUS, that is mutated in familial ALS, and SMN, the causative factor in Spinal Muscular Atrophy (SMA), cooperate to the same molecular pathway, i.e. regulation of alternative splicing, and that disturbances in SMN-regulated functions, either caused by depletion of SMN protein (as in the case of SMA) or by pathogenic interactions between FUS and SMN (as in the case of ALS) might be a common theme in both diseases. In this work, we followed these leads and tested their pathogenic relevance in vivo. FUS-associated ALS recapitulates, in transgenic mice, crucial molecular features that characterise mouse models of SMA, including defects in snRNPs distribution and in the alternative splicing of genes important for motor neurons. Notably, altering SMN levels by haploinsufficiency or overexpression does not impact the phenotypes of mouse or Drosophila models of FUS-mediated toxicity. Overall, these findings suggest that FUS and SMN functionally interact and that FUS may act downstream of SMN-regulated snRNP assembly in the regulation of alternative splicing and gene expression.
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37
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Boyd PJ, Tu WY, Shorrock HK, Groen EJN, Carter RN, Powis RA, Thomson SR, Thomson D, Graham LC, Motyl AAL, Wishart TM, Highley JR, Morton NM, Becker T, Becker CG, Heath PR, Gillingwater TH. Bioenergetic status modulates motor neuron vulnerability and pathogenesis in a zebrafish model of spinal muscular atrophy. PLoS Genet 2017; 13:e1006744. [PMID: 28426667 PMCID: PMC5417717 DOI: 10.1371/journal.pgen.1006744] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 05/04/2017] [Accepted: 04/05/2017] [Indexed: 11/18/2022] Open
Abstract
Degeneration and loss of lower motor neurons is the major pathological hallmark of spinal muscular atrophy (SMA), resulting from low levels of ubiquitously-expressed survival motor neuron (SMN) protein. One remarkable, yet unresolved, feature of SMA is that not all motor neurons are equally affected, with some populations displaying a robust resistance to the disease. Here, we demonstrate that selective vulnerability of distinct motor neuron pools arises from fundamental modifications to their basal molecular profiles. Comparative gene expression profiling of motor neurons innervating the extensor digitorum longus (disease-resistant), gastrocnemius (intermediate vulnerability), and tibialis anterior (vulnerable) muscles in mice revealed that disease susceptibility correlates strongly with a modified bioenergetic profile. Targeting of identified bioenergetic pathways by enhancing mitochondrial biogenesis rescued motor axon defects in SMA zebrafish. Moreover, targeting of a single bioenergetic protein, phosphoglycerate kinase 1 (Pgk1), was found to modulate motor neuron vulnerability in vivo. Knockdown of pgk1 alone was sufficient to partially mimic the SMA phenotype in wild-type zebrafish. Conversely, Pgk1 overexpression, or treatment with terazosin (an FDA-approved small molecule that binds and activates Pgk1), rescued motor axon phenotypes in SMA zebrafish. We conclude that global bioenergetics pathways can be therapeutically manipulated to ameliorate SMA motor neuron phenotypes in vivo.
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Affiliation(s)
- Penelope J. Boyd
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Integrative Physiology, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Wen-Yo Tu
- Sheffield Institute for Translation Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Hannah K. Shorrock
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Integrative Physiology, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Ewout J. N. Groen
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Integrative Physiology, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Roderick N. Carter
- University/British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Queens Medical Research Institute, Edinburgh, United Kingdom
| | - Rachael A. Powis
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Integrative Physiology, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Sophie R. Thomson
- Centre for Integrative Physiology, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Derek Thomson
- Centre for Integrative Physiology, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Laura C. Graham
- Division of Neurobiology, Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Anna A. L. Motyl
- Centre for Integrative Physiology, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Thomas M. Wishart
- Division of Neurobiology, Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - J. Robin Highley
- Sheffield Institute for Translation Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Nicholas M. Morton
- University/British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Queens Medical Research Institute, Edinburgh, United Kingdom
| | - Thomas Becker
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Neuroregeneration, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Catherina G. Becker
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Neuroregeneration, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Paul R. Heath
- Sheffield Institute for Translation Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Thomas H. Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Integrative Physiology, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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38
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Sleigh JN, Dawes JM, West SJ, Wei N, Spaulding EL, Gómez-Martín A, Zhang Q, Burgess RW, Cader MZ, Talbot K, Yang XL, Bennett DL, Schiavo G. Trk receptor signaling and sensory neuron fate are perturbed in human neuropathy caused by Gars mutations. Proc Natl Acad Sci U S A 2017; 114:E3324-E3333. [PMID: 28351971 PMCID: PMC5402433 DOI: 10.1073/pnas.1614557114] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Charcot-Marie-Tooth disease type 2D (CMT2D) is a peripheral nerve disorder caused by dominant, toxic, gain-of-function mutations in the widely expressed, housekeeping gene, GARS The mechanisms underlying selective nerve pathology in CMT2D remain unresolved, as does the cause of the mild-to-moderate sensory involvement that distinguishes CMT2D from the allelic disorder distal spinal muscular atrophy type V. To elucidate the mechanism responsible for the underlying afferent nerve pathology, we examined the sensory nervous system of CMT2D mice. We show that the equilibrium between functional subtypes of sensory neuron in dorsal root ganglia is distorted by Gars mutations, leading to sensory defects in peripheral tissues and correlating with overall disease severity. CMT2D mice display changes in sensory behavior concordant with the afferent imbalance, which is present at birth and nonprogressive, indicating that sensory neuron identity is prenatally perturbed and that a critical developmental insult is key to the afferent pathology. Through in vitro experiments, mutant, but not wild-type, GlyRS was shown to aberrantly interact with the Trk receptors and cause misactivation of Trk signaling, which is essential for sensory neuron differentiation and development. Together, this work suggests that both neurodevelopmental and neurodegenerative mechanisms contribute to CMT2D pathogenesis, and thus has profound implications for the timing of future therapeutic treatments.
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Affiliation(s)
- James N Sleigh
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London WC1N 3BG, United Kingdom;
| | - John M Dawes
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom
| | - Steven J West
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom
| | - Na Wei
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037
| | - Emily L Spaulding
- The Jackson Laboratory, Bar Harbor, ME 04609
- Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME 04469
| | - Adriana Gómez-Martín
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London WC1N 3BG, United Kingdom
| | - Qian Zhang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037
| | - Robert W Burgess
- The Jackson Laboratory, Bar Harbor, ME 04609
- Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME 04469
| | - M Zameel Cader
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom
| | - Kevin Talbot
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom
| | - Xiang-Lei Yang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037
| | - David L Bennett
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom
| | - Giampietro Schiavo
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London WC1N 3BG, United Kingdom;
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39
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Tu WY, Simpson JE, Highley JR, Heath PR. Spinal muscular atrophy: Factors that modulate motor neurone vulnerability. Neurobiol Dis 2017; 102:11-20. [PMID: 28161391 DOI: 10.1016/j.nbd.2017.01.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 01/10/2017] [Accepted: 01/31/2017] [Indexed: 01/07/2023] Open
Abstract
Spinal muscular atrophy (SMA), a leading genetic cause of infant death, is a neurodegenerative disease characterised by the selective loss of particular groups of motor neurones in the anterior horn of the spinal cord with concomitant muscle weakness. To date, no effective treatment is available, however, there are ongoing clinical trials are in place which promise much for the future. However, there remains an ongoing problem in trying to link a single gene loss to motor neurone degeneration. Fortunately, given successful disease models that have been established and intensive studies on SMN functions in the past ten years, we are fast approaching the stage of identifying the underlying mechanisms of SMA pathogenesis Here we discuss potential disease modifying factors on motor neurone vulnerability, in the belief that these factors give insight into the pathological mechanisms of SMA and therefore possible therapeutic targets.
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Affiliation(s)
- Wen-Yo Tu
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Julie E Simpson
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - J Robin Highley
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Paul R Heath
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK.
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40
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Huang Z, Zhang N, Li W, Cao J, Zhang L, Chen Y. Expression of CHODL in hepatocellular carcinoma affects invasion and migration of liver cancer cells. Oncol Lett 2016; 13:715-721. [PMID: 28356950 PMCID: PMC5351393 DOI: 10.3892/ol.2016.5466] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 09/30/2016] [Indexed: 01/15/2023] Open
Abstract
Hepatocellular carcinoma (HCC) is the third leading cause of cancer-associated death. Due to rapid progression and metastasis, the long-term survival remains poor for most patients. Thus, it is important to discover and develop novel preventive strategies and therapeutic approaches for HCC. Recent data show that chondrolectin (CHODL) is commonly overexpressed in the majority of lung cancers, indicating a possible correlation between CHODL and metastasis of lung cancer cells. Our investigation shows that the expression of CHODL is significantly decreased in HCC clinical samples and in HCC cell lines. Overexpression of CHODL in SMMC7721 cells with a lentiviral vector increased SMMC7721 cell migration and invasion. Our findings establish for the first time an association between human CHODL and HCC metastasis.
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Affiliation(s)
- Zejian Huang
- Department of Hepatobiliary and Pancreatic Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China
| | - Ning Zhang
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong 510000, P.R. China
| | - Wenda Li
- Department of Hepatobiliary and Pancreatic Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China
| | - Jun Cao
- Department of Hepatobiliary and Pancreatic Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China
| | - Lei Zhang
- Department of Hepatobiliary and Pancreatic Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China
| | - Yajin Chen
- Department of Hepatobiliary and Pancreatic Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China
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41
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Doktor TK, Hua Y, Andersen HS, Brøner S, Liu YH, Wieckowska A, Dembic M, Bruun GH, Krainer AR, Andresen BS. RNA-sequencing of a mouse-model of spinal muscular atrophy reveals tissue-wide changes in splicing of U12-dependent introns. Nucleic Acids Res 2016; 45:395-416. [PMID: 27557711 PMCID: PMC5224493 DOI: 10.1093/nar/gkw731] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 08/09/2016] [Accepted: 08/10/2016] [Indexed: 11/21/2022] Open
Abstract
Spinal Muscular Atrophy (SMA) is a neuromuscular disorder caused by insufficient levels of the Survival of Motor Neuron (SMN) protein. SMN is expressed ubiquitously and functions in RNA processing pathways that include trafficking of mRNA and assembly of snRNP complexes. Importantly, SMA severity is correlated with decreased snRNP assembly activity. In particular, the minor spliceosomal snRNPs are affected, and some U12-dependent introns have been reported to be aberrantly spliced in patient cells and animal models. SMA is characterized by loss of motor neurons, but the underlying mechanism is largely unknown. It is likely that aberrant splicing of genes expressed in motor neurons is involved in SMA pathogenesis, but increasing evidence indicates that pathologies also exist in other tissues. We present here a comprehensive RNA-seq study that covers multiple tissues in an SMA mouse model. We show elevated U12-intron retention in all examined tissues from SMA mice, and that U12-dependent intron retention is induced upon siRNA knock-down of SMN in HeLa cells. Furthermore, we show that retention of U12-dependent introns is mitigated by ASO treatment of SMA mice and that many transcriptional changes are reversed. Finally, we report on missplicing of several Ca2+ channel genes that may explain disrupted Ca2+ homeostasis in SMA and activation of Cdk5.
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Affiliation(s)
- Thomas Koed Doktor
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark.,The Villum Center for Bioanalytical Sciences, University of Southern Denmark, 5230 Odense, Denmark
| | - Yimin Hua
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Henriette Skovgaard Andersen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark.,The Villum Center for Bioanalytical Sciences, University of Southern Denmark, 5230 Odense, Denmark
| | - Sabrina Brøner
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark.,The Villum Center for Bioanalytical Sciences, University of Southern Denmark, 5230 Odense, Denmark
| | - Ying Hsiu Liu
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Anna Wieckowska
- Department of Gamete and Embryo Biology, Division of Reproductive Biology, Institute of Animal Reproduction and Food Research of Polish Academy of Sciences, 10-243 Olsztyn, Poland
| | - Maja Dembic
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark.,The Villum Center for Bioanalytical Sciences, University of Southern Denmark, 5230 Odense, Denmark
| | - Gitte Hoffmann Bruun
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark.,The Villum Center for Bioanalytical Sciences, University of Southern Denmark, 5230 Odense, Denmark
| | - Adrian R Krainer
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Brage Storstein Andresen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark .,The Villum Center for Bioanalytical Sciences, University of Southern Denmark, 5230 Odense, Denmark
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42
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Wertz MH, Winden K, Neveu P, Ng SY, Ercan E, Sahin M. Cell-type-specific miR-431 dysregulation in a motor neuron model of spinal muscular atrophy. Hum Mol Genet 2016; 25:2168-2181. [PMID: 27005422 DOI: 10.1093/hmg/ddw084] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 03/11/2016] [Indexed: 12/17/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal-recessive pediatric neurodegenerative disease characterized by selective loss of spinal motor neurons. It is caused by mutation in the survival of motor neuron 1, SMN1, gene and leads to loss of function of the full-length SMN protein. microRNAs (miRNAs) are small RNAs that are involved in post-transcriptional regulation of gene expression. Prior studies have implicated miRNAs in the pathogenesis of motor neuron disease. We hypothesized that motor neuron-specific miRNA expression changes are involved in their selective vulnerability in SMA. Therefore, we sought to determine the effect of SMN loss on miRNAs and their target mRNAs in spinal motor neurons. We used microarray and RNAseq to profile both miRNA and mRNA expression in primary spinal motor neuron cultures after acute SMN knockdown. By integrating the miRNA:mRNA profiles, a number of dysregulated miRNAs were identified with enrichment in differentially expressed putative mRNA targets. miR-431 expression was highly increased, and a number of its putative mRNA targets were significantly downregulated in motor neurons after SMN loss. Further, we found that miR-431 regulates motor neuron neurite length by targeting several molecules previously identified to play a role in motor neuron axon outgrowth, including chondrolectin. Together, our findings indicate that cell-type-specific dysregulation of miR-431 plays a role in the SMA motor neuron phenotype.
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Affiliation(s)
- Mary H Wertz
- Department of Neurology, The F. M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Kellen Winden
- Department of Neurology, The F. M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Pierre Neveu
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Shi-Yan Ng
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA Neurotherapeutics Laboratory, Institute of Molecular and Cell Biology, A*STAR, Singapore 138673, Singapore
| | - Ebru Ercan
- Department of Neurology, The F. M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Mustafa Sahin
- Department of Neurology, The F. M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
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43
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Zhao X, Feng Z, Ling KKY, Mollin A, Sheedy J, Yeh S, Petruska J, Narasimhan J, Dakka A, Welch EM, Karp G, Chen KS, Metzger F, Ratni H, Lotti F, Tisdale S, Naryshkin NA, Pellizzoni L, Paushkin S, Ko CP, Weetall M. Pharmacokinetics, pharmacodynamics, and efficacy of a small-molecule SMN2 splicing modifier in mouse models of spinal muscular atrophy. Hum Mol Genet 2016; 25:1885-1899. [PMID: 26931466 PMCID: PMC5062580 DOI: 10.1093/hmg/ddw062] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 02/22/2016] [Indexed: 12/26/2022] Open
Abstract
Spinal muscular atrophy (SMA) is caused by the loss or mutation of both copies of the survival motor neuron 1 (SMN1) gene. The related SMN2 gene is retained, but due to alternative splicing of exon 7, produces insufficient levels of the SMN protein. Here, we systematically characterize the pharmacokinetic and pharmacodynamics properties of the SMN splicing modifier SMN-C1. SMN-C1 is a low-molecular weight compound that promotes the inclusion of exon 7 and increases production of SMN protein in human cells and in two transgenic mouse models of SMA. Furthermore, increases in SMN protein levels in peripheral blood mononuclear cells and skin correlate with those in the central nervous system (CNS), indicating that a change of these levels in blood or skin can be used as a non-invasive surrogate to monitor increases of SMN protein levels in the CNS. Consistent with restored SMN function, SMN-C1 treatment increases the levels of spliceosomal and U7 small-nuclear RNAs and corrects RNA processing defects induced by SMN deficiency in the spinal cord of SMNΔ7 SMA mice. A 100% or greater increase in SMN protein in the CNS of SMNΔ7 SMA mice robustly improves the phenotype. Importantly, a ∼50% increase in SMN leads to long-term survival, but the SMA phenotype is only partially corrected, indicating that certain SMA disease manifestations may respond to treatment at lower doses. Overall, we provide important insights for the translation of pre-clinical data to the clinic and further therapeutic development of this series of molecules for SMA treatment.
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Affiliation(s)
- Xin Zhao
- PTC Therapeutics, Inc., South Plainfield, NJ 07080, USA
| | - Zhihua Feng
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Karen K Y Ling
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Anna Mollin
- PTC Therapeutics, Inc., South Plainfield, NJ 07080, USA
| | | | - Shirley Yeh
- PTC Therapeutics, Inc., South Plainfield, NJ 07080, USA
| | | | | | - Amal Dakka
- PTC Therapeutics, Inc., South Plainfield, NJ 07080, USA
| | - Ellen M Welch
- PTC Therapeutics, Inc., South Plainfield, NJ 07080, USA
| | - Gary Karp
- PTC Therapeutics, Inc., South Plainfield, NJ 07080, USA
| | - Karen S Chen
- SMA Foundation, 888 Seventh Avenue, Suite 400, New York, NY 10019, USA
| | - Friedrich Metzger
- F. Hoffmann-La Roche, Pharmaceutical Research and Early Development, Roche Innovation Center Basel, Grenzacherstrasse 124, Basel 4070, Switzerland
| | - Hasane Ratni
- F. Hoffmann-La Roche, Pharmaceutical Research and Early Development, Roche Innovation Center Basel, Grenzacherstrasse 124, Basel 4070, Switzerland
| | - Francesco Lotti
- Department of Pathology and Cell Biology, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA and
| | - Sarah Tisdale
- Department of Pathology and Cell Biology, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA and
| | | | - Livio Pellizzoni
- Department of Pathology and Cell Biology, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA and
| | - Sergey Paushkin
- SMA Foundation, 888 Seventh Avenue, Suite 400, New York, NY 10019, USA
| | - Chien-Ping Ko
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA,
| | - Marla Weetall
- PTC Therapeutics, Inc., South Plainfield, NJ 07080, USA,
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44
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Sleigh JN, Weir GA, Schiavo G. A simple, step-by-step dissection protocol for the rapid isolation of mouse dorsal root ganglia. BMC Res Notes 2016; 9:82. [PMID: 26864470 PMCID: PMC4750296 DOI: 10.1186/s13104-016-1915-8] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 02/03/2016] [Indexed: 11/25/2022] Open
Abstract
Background The cell bodies of sensory neurons, which transmit information from the external environment to the spinal cord, can be found at all levels of the spinal column in paired structures called dorsal root ganglia (DRG). Rodent DRG neurons have long been studied in the laboratory to improve understanding of sensory nerve development and function, and have been instrumental in determining mechanisms underlying pain and neurodegeneration in disorders of the peripheral nervous system. Here, we describe a simple, step-by-step protocol for the swift isolation of mouse DRG, which can be enzymatically dissociated to produce fully differentiated primary neuronal cultures, or processed for downstream analyses, such as immunohistochemistry or RNA profiling. Findings After dissecting out the spinal column, from the base of the skull to the level of the femurs, it can be cut down the mid-line and the spinal cord and meninges removed, before extracting the DRG and detaching unwanted axons. This protocol allows the easy and rapid isolation of DRG with minimal practice and dissection experience. The process is both faster and less technically challenging than extracting the ganglia from the in situ column after performing a dorsal laminectomy. Conclusions This approach reduces the time required to collect DRG, thereby improving efficiency, permitting less opportunity for tissue deterioration, and, ultimately, increasing the chances of generating healthy primary DRG cultures or high quality, reproducible experiments using DRG tissue.
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Affiliation(s)
- James N Sleigh
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, WC1 N 3BG, UK.
| | - Greg A Weir
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, UK.
| | - Giampietro Schiavo
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, WC1 N 3BG, UK.
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45
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Somers E, Lees RD, Hoban K, Sleigh JN, Zhou H, Muntoni F, Talbot K, Gillingwater TH, Parson SH. Vascular Defects and Spinal Cord Hypoxia in Spinal Muscular Atrophy. Ann Neurol 2016; 79:217-30. [PMID: 26506088 DOI: 10.1002/ana.24549] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 09/11/2015] [Accepted: 10/18/2015] [Indexed: 01/22/2023]
Abstract
OBJECTIVE Spinal muscular atrophy (SMA) is a major inherited cause of infant death worldwide. It results from mutations in a single, ubiquitously expressed gene (SMN1), with loss of lower motor neurons being the primary pathological signature. Systemic defects have also been reported in SMA patients and animal models. We investigated whether defects associated with the vasculature contribute to motor neuron pathology in SMA. METHODS Development and integrity of the capillary bed was examined in skeletal muscle and spinal cord of SMA mice, and muscle biopsies from SMA patients and controls, using quantitative morphometric approaches on immunohistochemically labeled tissue. Pimonidazole hydrochloride-based assays were used to identify functional hypoxia. RESULTS The capillary bed in muscle and spinal cord was normal in presymptomatic SMA mice (postnatal day 1), but failed to match subsequent postnatal development in control littermates. At mid- and late-symptomatic time points, the extent of the vascular architecture observed in two distinct mouse models of SMA was ∼50% of that observed in control animals. Skeletal muscle biopsies from human patients confirmed the presence of developmentally similar, significant vascular depletion in severe SMA. Hypovascularity in SMA mouse spinal cord was accompanied by significant functional hypoxia and defects in the blood-spinal cord barrier. INTERPRETATION Our results indicate that vascular defects are a major feature of severe forms of SMA, present in both mouse models and patients, resulting in functional hypoxia of motor neurons. Thus, abnormal vascular development and resulting hypoxia may contribute to the pathogenesis of SMA.
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Affiliation(s)
- Eilidh Somers
- Center for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.,Euan MacDonald Center for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Robert D Lees
- Center for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Katie Hoban
- Center for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - James N Sleigh
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Haiyan Zhou
- Dubowitz Neuromuscular Center, Institute of Child Health, University College London, London, United Kingdom
| | - Francesco Muntoni
- Dubowitz Neuromuscular Center, Institute of Child Health, University College London, London, United Kingdom
| | - Kevin Talbot
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Thomas H Gillingwater
- Center for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.,Euan MacDonald Center for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Simon H Parson
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom.,Euan MacDonald Center for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
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46
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Gao X, Teng Y, Luo J, Huang L, Li M, Zhang Z, Ma YC, Ma L. The survival motor neuron gene smn-1 interacts with the U2AF large subunit gene uaf-1 to regulate Caenorhabditis elegans lifespan and motor functions. RNA Biol 2015; 11:1148-60. [PMID: 25483032 DOI: 10.4161/rna.36100] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Spinal muscular atrophy (SMA), the most frequent human congenital motor neuron degenerative disease, is caused by loss-of-function mutations in the highly conserved survival motor neuron gene SMN1. Mutations in SMN could affect several molecular processes, among which aberrant pre-mRNA splicing caused by defective snRNP biogenesis is hypothesized as a major cause of SMA. To date little is known about the interactions of SMN with other splicing factor genes and how SMN affects splicing in vivo. The nematode Caenorhabditis elegans carries a single ortholog of SMN, smn-1, and has been used as a model for studying the molecular functions of SMN. We analyzed RNA splicing of reporter genes in an smn-1 deletion mutant and found that smn-1 is required for efficient splicing at weak 3' splice sites. Genetic studies indicate that the defective lifespan and motor functions of the smn-1 deletion mutants could be significantly improved by mutations of the splicing factor U2AF large subunit gene uaf-1. In smn-1 mutants we detected a reduced expression of U1 and U5 snRNAs and an increased expression of U2, U4 and U6 snRNAs. Our study verifies an essential role of smn-1 for RNA splicing in vivo, identifies the uaf-1 gene as a potential genetic modifier of smn-1 mutants, and suggests that SMN-1 has multifaceted effects on the expression of spliceosomal snRNAs.
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Affiliation(s)
- Xiaoyang Gao
- a State Key Laboratory of Medical Genetics; School of Life Sciences ; Central South University ; Changsha , Hunan , China
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47
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Ramanoudjame L, Rocancourt C, Lainé J, Klein A, Joassard L, Gartioux C, Fleury M, Lyphout L, Kabashi E, Ciura S, Cousin X, Allamand V. Two novel COLVI long chains in zebrafish that are essential for muscle development. Hum Mol Genet 2015; 24:6624-39. [PMID: 26362255 DOI: 10.1093/hmg/ddv368] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 09/04/2015] [Indexed: 12/25/2022] Open
Abstract
Collagen VI (COLVI), a protein ubiquitously expressed in connective tissues, is crucial for structural integrity, cellular adhesion, migration and survival. Six different genes are recognized in mammalians, encoding six COLVI-chains that assemble as two 'short' (α1, α2) and one 'long' chain (theoretically any one of α3-6). In humans, defects in the most widely expressed heterotrimer (α123), due to mutations in the COL6A1-3 genes, cause a heterogeneous group of neuromuscular disorders, collectively termed COLVI-related muscle disorders. Little is known about the function(s) of the recently described α4-6 chains and no mutations have been detected yet. In this study, we characterized two novel COLVI long chains in zebrafish that are most homologous to the mammalian α4 chain; therefore, we named the corresponding genes col6a4a and col6a4b. These orthologues represent ancestors of the mammalian Col6a4-6 genes. By in situ hybridization and RT-qPCR, we unveiled a distinctive expression kinetics for col6a4b, compared with the other col6a genes. Using morpholino antisense oligonucleotides targeting col6a4a, col6a4b and col6a2, we modelled partial and complete COLVI deficiency, respectively. All morphant embryos presented altered muscle structure and impaired motility. While apoptosis was not drastically increased, autophagy induction was defective in all morphants. Furthermore, motoneuron axon growth was abnormal in these morphants. Importantly, some phenotypical differences emerged between col6a4a and col6a4b morphants, suggesting only partial functional redundancy. Overall, our results further confirm the importance of COLVI in zebrafish muscle development and may provide important clues for potential human phenotypes associated with deficiency of the recently described COLVI-chains.
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Affiliation(s)
- Laetitia Ramanoudjame
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, Paris F-75013, France, Institut de Myologie, Paris F-75013, France
| | | | - Jeanne Lainé
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, Paris F-75013, France, Institut de Myologie, Paris F-75013, France, Département de Physiologie, Sorbonne Universités UPMC Paris 06, Site Pitié-Salpêtrière, Paris F-75013, France
| | - Arnaud Klein
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, Paris F-75013, France, Institut de Myologie, Paris F-75013, France
| | | | - Corine Gartioux
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, Paris F-75013, France, Institut de Myologie, Paris F-75013, France
| | - Marjory Fleury
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, Paris F-75013, France, Institut de Myologie, Paris F-75013, France
| | - Laura Lyphout
- Fish Ecophysiology Group, Ifremer, L'Houmeau F-17137, France
| | - Edor Kabashi
- Sorbonne Universités Paris VI, UMR CNRS 1127 UPMC, INSERM U 1127, CNRS UMR 7225, Institut du Cerveau et de la Moelle épinière-ICM, Paris, France and
| | - Sorana Ciura
- Sorbonne Universités Paris VI, UMR CNRS 1127 UPMC, INSERM U 1127, CNRS UMR 7225, Institut du Cerveau et de la Moelle épinière-ICM, Paris, France and
| | - Xavier Cousin
- Fish Ecophysiology Group, Ifremer, L'Houmeau F-17137, France, INRA LPGP, Campus de Beaulieu, Rennes F-35042, France
| | - Valérie Allamand
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, Paris F-75013, France, Institut de Myologie, Paris F-75013, France,
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48
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Abstract
Motor neuron diseases are neurological disorders characterized primarily by the degeneration of spinal motor neurons, skeletal muscle atrophy, and debilitating and often fatal motor dysfunction. Spinal muscular atrophy (SMA) is an autosomal-recessive motor neuron disease of high incidence and severity and the most common genetic cause of infant mortality. SMA is caused by homozygous mutations in the survival motor neuron 1 (SMN1) gene and retention of at least one copy of the hypomorphic gene paralog SMN2. Early studies established a loss-of-function disease mechanism involving ubiquitous SMN deficiency and suggested SMN upregulation as a possible therapeutic approach. In recent years, greater knowledge of the central role of SMN in RNA processing combined with deep characterization of animal models of SMA has significantly advanced our understanding of the cellular and molecular basis of the disease. SMA is emerging as an RNA disease not limited to motor neurons, but one that involves dysfunction of motor circuits that comprise multiple neuronal subpopulations and possibly other cell types. Advances in SMA research have also led to the development of several potential therapeutics shown to be effective in animal models of SMA that are now in clinical trials. These agents offer unprecedented promise for the treatment of this still incurable neurodegenerative disease.
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49
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Grice SJ, Sleigh JN, Motley WW, Liu JL, Burgess RW, Talbot K, Cader MZ. Dominant, toxic gain-of-function mutations in gars lead to non-cell autonomous neuropathology. Hum Mol Genet 2015; 24:4397-406. [PMID: 25972375 PMCID: PMC4492401 DOI: 10.1093/hmg/ddv176] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 05/06/2015] [Indexed: 12/15/2022] Open
Abstract
Charcot-Marie-Tooth (CMT) neuropathies are collectively the most common hereditary neurological condition and a major health burden for society. Dominant mutations in the gene GARS, encoding the ubiquitous enzyme, glycyl-tRNA synthetase (GlyRS), cause peripheral nerve degeneration and lead to CMT disease type 2D. This genetic disorder exemplifies a recurring motif in neurodegeneration, whereby mutations in essential, widely expressed genes have selective deleterious consequences for the nervous system. Here, using novel Drosophila models, we show a potential solution to this phenomenon. Ubiquitous expression of mutant GlyRS leads to motor deficits, progressive neuromuscular junction (NMJ) denervation and pre-synaptic build-up of mutant GlyRS. Intriguingly, neuronal toxicity is, at least in part, non-cell autonomous, as expression of mutant GlyRS in mesoderm or muscle alone results in similar pathology. This mutant GlyRS toxic gain-of-function, which is WHEP domain-dependent, coincides with abnormal NMJ assembly, leading to synaptic degeneration, and, ultimately, reduced viability. Our findings suggest that mutant GlyRS gains access to ectopic sub-compartments of the motor neuron, providing a possible explanation for the selective neuropathology caused by mutations in a widely expressed gene.
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Affiliation(s)
- Stuart J Grice
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3PT, UK
| | - James N Sleigh
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK, The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - William W Motley
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA and
| | - Ji-Long Liu
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3PT, UK
| | | | - Kevin Talbot
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - M Zameel Cader
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK, The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK,
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50
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Henriques A, Kastner S, Chatzikonstantinou E, Pitzer C, Plaas C, Kirsch F, Wafzig O, Krüger C, Spoelgen R, Gonzalez De Aguilar JL, Gretz N, Schneider A. Gene expression changes in spinal motoneurons of the SOD1(G93A) transgenic model for ALS after treatment with G-CSF. Front Cell Neurosci 2015; 8:464. [PMID: 25653590 PMCID: PMC4299451 DOI: 10.3389/fncel.2014.00464] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 12/20/2014] [Indexed: 12/12/2022] Open
Abstract
Background: Amyotrophic lateral sclerosis (ALS) is an incurable fatal motoneuron disease with a lifetime risk of approximately 1:400. It is characterized by progressive weakness, muscle wasting, and death ensuing 3–5 years after diagnosis. Granulocyte-colony stimulating factor (G-CSF) is a drug candidate for ALS, with evidence for efficacy from animal studies and interesting data from pilot clinical trials. To gain insight into the disease mechanisms and mode of action of G-CSF, we performed gene expression profiling on isolated lumbar motoneurons from SOD1G93A mice, the most frequently studied animal model for ALS, with and without G-CSF treatment. Results: Motoneurons from SOD1G93A mice present a distinct gene expression profile in comparison to controls already at an early disease stage (11 weeks of age), when treatment was initiated. The degree of deregulation increases at a time where motor symptoms are obvious (15 weeks of age). Upon G-CSF treatment, transcriptomic deregulations of SOD1G93A motoneurons were notably restored. Discriminant analysis revealed that SOD1 mice treated with G-CSF has a transcriptom close to presymptomatic SOD1 mice or wild type mice. Some interesting genes modulated by G-CSF treatment relate to neuromuscular function such as CCR4-NOT or Prss12. Conclusions: Our data suggest that G-CSF is able to re-adjust gene expression in symptomatic SOD1G93A motoneurons. This provides further arguments for G-CSF as a promising drug candidate for ALS.
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Affiliation(s)
- Alexandre Henriques
- INSERM, U1118, Mécanismes Centraux et Péripheriques de la Neurodégénérescence Strasbourg, France ; UMRS1118, Fédération de Médecine Translationnelle de Strasbourg Université de Strasbourg, France
| | | | | | | | | | | | | | | | | | - Jose-Luis Gonzalez De Aguilar
- INSERM, U1118, Mécanismes Centraux et Péripheriques de la Neurodégénérescence Strasbourg, France ; UMRS1118, Fédération de Médecine Translationnelle de Strasbourg Université de Strasbourg, France
| | - Norbert Gretz
- Medical Research Center, Medical Faculty Mannheim, University of Heidelberg Mannheim, Germany
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