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R-Ras1 and R-Ras2 Expression in Anatomical Regions and Cell Types of the Central Nervous System. Int J Mol Sci 2022; 23:ijms23020978. [PMID: 35055164 PMCID: PMC8781598 DOI: 10.3390/ijms23020978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 01/10/2022] [Indexed: 11/20/2022] Open
Abstract
Since the optic nerve is one of the most myelinated tracts in the central nervous system (CNS), many myelin diseases affect the visual system. In this sense, our laboratory has recently reported that the GTPases R-Ras1 and R-Ras2 are essential for oligodendrocyte survival and maturation. Hypomyelination produced by the absence of one or both proteins triggers axonal degeneration and loss of visual and motor function. However, little is known about R-Ras specificity and other possible roles that they could play in the CNS. In this work, we describe how a lack of R-Ras1 and/or R-Ras2 could not be compensated by increased expression of the closely related R-Ras3 or classical Ras. We further studied R-Ras1 and R-Ras2 expression within different CNS anatomical regions, finding that both were more abundant in less-myelinated regions, suggesting their expression in non-oligodendroglial cells. Finally, using confocal immunostaining colocalization, we report for the first time that R-Ras2 is specifically expressed in neurons. Neither microglia nor astrocytes expressed R-Ras1 or R-Ras2. These results open a new avenue for the study of neuronal R-Ras2’s contribution to the process of myelination.
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Alcover-Sanchez B, Garcia-Martin G, Escudero-Ramirez J, Gonzalez-Riano C, Lorenzo P, Gimenez-Cassina A, Formentini L, de la Villa-Polo P, Pereira MP, Wandosell F, Cubelos B. Absence of R-Ras1 and R-Ras2 causes mitochondrial alterations that trigger axonal degeneration in a hypomyelinating disease model. Glia 2020; 69:619-637. [PMID: 33010069 DOI: 10.1002/glia.23917] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 08/18/2020] [Accepted: 09/21/2020] [Indexed: 12/11/2022]
Abstract
Fast synaptic transmission in vertebrates is critically dependent on myelin for insulation and metabolic support. Myelin is produced by oligodendrocytes (OLs) that maintain multilayered membrane compartments that wrap around axonal fibers. Alterations in myelination can therefore lead to severe pathologies such as multiple sclerosis. Given that hypomyelination disorders have complex etiologies, reproducing clinical symptoms of myelin diseases from a neurological perspective in animal models has been difficult. We recently reported that R-Ras1-/- and/or R-Ras2-/- mice, which lack GTPases essential for OL survival and differentiation processes, present different degrees of hypomyelination in the central nervous system with a compounded hypomyelination in double knockout (DKO) mice. Here, we discovered that the loss of R-Ras1 and/or R-Ras2 function is associated with aberrant myelinated axons with increased numbers of mitochondria, and a disrupted mitochondrial respiration that leads to increased reactive oxygen species levels. Consequently, aberrant myelinated axons are thinner with cytoskeletal phosphorylation patterns typical of axonal degeneration processes, characteristic of myelin diseases. Although we observed different levels of hypomyelination in a single mutant mouse, the combined loss of function in DKO mice lead to a compromised axonal integrity, triggering the loss of visual function. Our findings demonstrate that the loss of R-Ras function reproduces several characteristics of hypomyelinating diseases, and we therefore propose that R-Ras1-/- and R-Ras2-/- neurological models are valuable approaches for the study of these myelin pathologies.
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Affiliation(s)
- Berta Alcover-Sanchez
- Departamento de Biología Molecular and Centro Biología Molecular "Severo Ochoa", Universidad Autónoma de Madrid - Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Gonzalo Garcia-Martin
- Departamento de Biología Molecular and Centro Biología Molecular "Severo Ochoa", Universidad Autónoma de Madrid - Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Juan Escudero-Ramirez
- Departamento de Biología Molecular and Centro Biología Molecular "Severo Ochoa", Universidad Autónoma de Madrid - Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Carolina Gonzalez-Riano
- CEMBIO (Centre for Metabolomics and Bioanalysis), Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Madrid, Spain
| | - Paz Lorenzo
- CEMBIO (Centre for Metabolomics and Bioanalysis), Facultad de Farmacia, Universidad San Pablo-CEU, CEU Universities, Madrid, Spain
| | - Alfredo Gimenez-Cassina
- Departamento de Biología Molecular and Centro Biología Molecular "Severo Ochoa", Universidad Autónoma de Madrid - Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Laura Formentini
- Departamento de Biología Molecular and Centro Biología Molecular "Severo Ochoa", Universidad Autónoma de Madrid - Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Pedro de la Villa-Polo
- Departamento de Biología de Sistemas, Universidad de Alcalá, Madrid, Spain.,Grupo de Neurofisiología Visual, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - Marta P Pereira
- Departamento de Biología Molecular and Centro Biología Molecular "Severo Ochoa", Universidad Autónoma de Madrid - Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Francisco Wandosell
- Departamento de Biología Molecular and Centro Biología Molecular "Severo Ochoa", Universidad Autónoma de Madrid - Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Beatriz Cubelos
- Departamento de Biología Molecular and Centro Biología Molecular "Severo Ochoa", Universidad Autónoma de Madrid - Consejo Superior de Investigaciones Científicas, Madrid, Spain
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3
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Vanderver A, Bernard G, Helman G, Sherbini O, Boeck R, Cohn J, Collins A, Demarest S, Dobbins K, Emrick L, Fraser JL, Masser-Frye D, Hayward J, Karmarkar S, Keller S, Mirrop S, Mitchell W, Pathak S, Sherr E, van Haren K, Waters E, Wilson JL, Zhorne L, Schiffmann R, van der Knaap MS, Pizzino A, Dubbs H, Shults J, Simons C, Taft RJ. Randomized Clinical Trial of First-Line Genome Sequencing in Pediatric White Matter Disorders. Ann Neurol 2020; 88:264-273. [PMID: 32342562 DOI: 10.1002/ana.25757] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 04/19/2020] [Accepted: 04/20/2020] [Indexed: 01/26/2023]
Abstract
OBJECTIVE Genome sequencing (GS) is promising for unsolved leukodystrophies, but its efficacy has not been prospectively studied. METHODS A prospective time-delayed crossover design trial of GS to assess the efficacy of GS as a first-line diagnostic tool for genetic white matter disorders took place between December 1, 2015 and September 27, 2017. Patients were randomized to receive GS immediately with concurrent standard of care (SoC) testing, or to receive SoC testing for 4 months followed by GS. RESULTS Thirty-four individuals were assessed at interim review. The genetic origin of 2 patient's leukoencephalopathy was resolved before randomization. Nine patients were stratified to the immediate intervention group and 23 patients to the delayed-GS arm. The efficacy of GS was significant relative to SoC in the immediate (5/9 [56%] vs 0/9 [0%]; Wild-Seber, p < 0.005) and delayed (control) arms (14/23 [61%] vs 5/23 [22%]; Wild-Seber, p < 0.005). The time to diagnosis was significantly shorter in the immediate-GS group (log-rank test, p = 0.04). The overall diagnostic efficacy of combined GS and SoC approaches was 26 of 34 (76.5%, 95% confidence interval = 58.8-89.3%) in <4 months, greater than historical norms of <50% over 5 years. Owing to loss of clinical equipoise, the trial design was altered to a single-arm observational study. INTERPRETATION In this study, first-line GS provided earlier and greater diagnostic efficacy in white matter disorders. We provide an evidence-based diagnostic testing algorithm to enable appropriate clinical GS utilization in this population. ANN NEUROL 2020;88:264-273.
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Affiliation(s)
- Adeline Vanderver
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Geneviève Bernard
- Departments of Neurology and Neurosurgery, Pediatrics, and Human Genetics, McGill University, Montreal, Quebec, Canada.,Department of Specialized Medicine, Division of Medical Genetics, Montreal Children's Hospital and McGill University Health Centre, Montreal, Quebec, Canada.,Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Guy Helman
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland, Australia.,Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Omar Sherbini
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Ryan Boeck
- Child Neurology Consultants of Austin, Austin, Texas, USA.,University of Texas at Austin Dell Medical School, Austin, Texas, USA
| | - Jeffrey Cohn
- Family Medicine, Broadlands Family Practice at Ashburn, Ashburn, Virginia, USA
| | - Abigail Collins
- Department of Neurology, Anschutz Medical Campus, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Scott Demarest
- Department of Neurology, Anschutz Medical Campus, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Katherine Dobbins
- Walter Reed National Military Medical Center, Bethesda, Maryland, USA
| | - Lisa Emrick
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Jamie L Fraser
- Division of Genetics and Metabolism, Rare Disease Institute, Children's National Hospital, Washington, District of Columbia, USA.,George Washington University, Washington, District of Columbia, USA
| | | | - Jean Hayward
- Department of Pediatrics, Kaiser Oakland, Oakland, California, USA
| | - Swati Karmarkar
- Department of Neurology, Le Bonheur Children's Hospital, Memphis, Tennessee, USA.,Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Stephanie Keller
- Division of Neurology, Department of Pediatrics, Emory University, Atlanta, Georgia, USA
| | | | - Wendy Mitchell
- Division of Neurology, Children's Hospital of Los Angeles, Los Angeles, California, USA.,Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Sheel Pathak
- Clinical Neurology, Washington University Clinical Associates, St Louis, Missouri, USA.,Department of Neurology, Washington University School of Medicine, St Louis, Missouri, USA
| | - Elliott Sherr
- Department of Neurology, University of California, San Francisco School of Medicine, San Francisco, California, USA
| | - Keith van Haren
- Department of Neurology, Stanford University Medical Center, Stanford, California, USA
| | - Erica Waters
- Pediatric Associates of Stockton, Stockton, California, USA
| | - Jenny L Wilson
- Division of Pediatric Neurology, Oregon Health & Science University School of Medicine, Portland, Oregon, USA
| | - Leah Zhorne
- Stead Family Department of Pediatrics, Carver College of Medicine, University of Iowa Health Care, Iowa City, Iowa, USA
| | - Raphael Schiffmann
- Institute of Metabolic Disease, Baylor Scott & White Research Institute, Dallas, Texas, USA
| | - Marjo S van der Knaap
- Department of Child Neurology, VU University Medical Center, Amsterdam, the Netherlands.,Department of Functional Genomics, Amsterdam Neuroscience, VU University, Amsterdam, the Netherlands
| | - Amy Pizzino
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Holly Dubbs
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Justine Shults
- Department of Biostatistics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Cas Simons
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland, Australia.,Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia
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4
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Sarret C. Leukodystrophies and genetic leukoencephalopathies in children. Rev Neurol (Paris) 2020; 176:10-19. [DOI: 10.1016/j.neurol.2019.04.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 04/15/2019] [Accepted: 04/16/2019] [Indexed: 12/11/2022]
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Abstract
To study cellular and molecular mechanisms of demyelination and remyelination in vivo, we developed a transgenic zebrafish line, Tg(mbp:mCherry-NTR), in which expression of the bacterial enzyme nitroreductase (NTR) is driven under the myelin basic protein promoter (mbp) and thus is expressed in myelinating glia. When NTR-expressing larvae are treated with the prodrug metronidazole, the reaction between NTR and Mtz results in a toxic metabolite which selectively kills NTR-expressing cells. Using the Tg(mbp:mCherry-NTR) line, we can ablate two-thirds of oligodendrocytes following a 2-day MTZ treatment. Demyelination is evident seven days later, and remyelination is observed 16 days after Mtz treatment. The Tg(mbp:mCherry-NTR) model can be used to image cell behavior during, and to test how genetic manipulations or chemical compounds regulate, demyelination and remyelination. In this chapter, we describe the methods we used to characterize the oligodendrocyte loss, demyelination and remyelination in the Tg(mbp:mCherry-NTR) model.
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6
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Early JJ, Cole KL, Williamson JM, Swire M, Kamadurai H, Muskavitch M, Lyons DA. An automated high-resolution in vivo screen in zebrafish to identify chemical regulators of myelination. eLife 2018; 7:35136. [PMID: 29979149 PMCID: PMC6056238 DOI: 10.7554/elife.35136] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 07/05/2018] [Indexed: 12/23/2022] Open
Abstract
Myelinating oligodendrocytes are essential for central nervous system (CNS) formation and function. Their disruption is implicated in numerous neurodevelopmental, neuropsychiatric and neurodegenerative disorders. However, recent studies have indicated that oligodendrocytes may be tractable for treatment of disease. In recent years, zebrafish have become well established for the study of myelinating oligodendrocyte biology and drug discovery in vivo. Here, by automating the delivery of zebrafish larvae to a spinning disk confocal microscope, we were able to automate high-resolution imaging of myelinating oligodendrocytes in vivo. From there, we developed an image analysis pipeline that facilitated a screen of compounds with epigenetic and post-translational targets for their effects on regulating myelinating oligodendrocyte number. This screen identified novel compounds that strongly promote myelinating oligodendrocyte formation in vivo. Our imaging platform and analysis pipeline is flexible and can be employed for high-resolution imaging-based screens of broad interest using zebrafish.
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Affiliation(s)
- Jason J Early
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom.,United Kingdom Zebrafish screening facility, University of Edinburgh, Edinburgh, United Kingdom
| | - Katy Lh Cole
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Jill M Williamson
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Matthew Swire
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom.,MRC Centre for Regenerative Medicine, Edinburgh, United Kingdom
| | | | | | - David A Lyons
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom.,United Kingdom Zebrafish screening facility, University of Edinburgh, Edinburgh, United Kingdom
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7
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R-Ras1 and R-Ras2 Are Essential for Oligodendrocyte Differentiation and Survival for Correct Myelination in the Central Nervous System. J Neurosci 2018; 38:5096-5110. [PMID: 29720552 DOI: 10.1523/jneurosci.3364-17.2018] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 03/14/2018] [Accepted: 04/10/2018] [Indexed: 12/21/2022] Open
Abstract
Rapid and effective neural transmission of information requires correct axonal myelination. Modifications in myelination alter axonal capacity to transmit electric impulses and enable pathological conditions. In the CNS, oligodendrocytes (OLs) myelinate axons, a complex process involving various cellular interactions. However, we know little about the mechanisms that orchestrate correct myelination. Here, we demonstrate that OLs express R-Ras1 and R-Ras2. Using female and male mutant mice to delete these proteins, we found that activation of the PI3K/Akt and Erk1/2-MAPK pathways was weaker in mice lacking one or both of these GTPases, suggesting that both proteins coordinate the activity of these two pathways. Loss of R-Ras1 and/or R-Ras2 diminishes the number of OLs in major myelinated CNS tracts and increases the proportion of immature OLs. In R-Ras1-/- and R-Ras2-/--null mice, OLs show aberrant morphologies and fail to differentiate correctly into myelin-forming phenotypes. The smaller OL population and abnormal OL maturation induce severe hypomyelination, with shorter nodes of Ranvier in R-Ras1-/- and/or R-Ras2-/- mice. These defects explain the slower conduction velocity of myelinated axons that we observed in the absence of R-Ras1 and R-Ras2. Together, these results suggest that R-Ras1 and R-Ras2 are upstream elements that regulate the survival and differentiation of progenitors into OLs through the PI3K/Akt and Erk1/2-MAPK pathways for proper myelination.SIGNIFICANCE STATEMENT In this study, we show that R-Ras1 and R-Ras2 play essential roles in regulating myelination in vivo and control fundamental aspects of oligodendrocyte (OL) survival and differentiation through synergistic activation of PI3K/Akt and Erk1/2-MAPK signaling. Mice lacking R-Ras1 and/or R-Ras2 show a diminished OL population with a higher proportion of immature OLs, explaining the observed hypomyelination in main CNS tracts. In vivo electrophysiology recordings demonstrate a slower conduction velocity of nerve impulses in the absence of R-Ras1 and R-Ras2. Therefore, R-Ras1 and R-Ras2 are essential for proper axonal myelination and accurate neural transmission.
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8
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Hou X, Zhang R, Wang J, Li Y, Li F, Zhang Y, Zheng X, Shen Y, Wang Y, Zhou L. CLC-2 is a positive modulator of oligodendrocyte precursor cell differentiation and myelination. Mol Med Rep 2018; 17:4515-4523. [PMID: 29344669 PMCID: PMC5802228 DOI: 10.3892/mmr.2018.8439] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 12/18/2017] [Indexed: 01/20/2023] Open
Abstract
Oligodendrocytes (OLs) are myelin-forming cells that are present within the central nervous system. Impaired oligodendrocyte precursor cell (OPC) differentiation into mature OLs is a major cause of demyelination diseases. Therefore, identifying the underlying molecular mechanisms of OPC differentiation is crucial to understand the processes of myelination and demyelination. It has been acknowledged that various extrinsic and intrinsic factors are involved in the control of OPC differentiation; however, the function of ion channels, particularly the voltage-gated chloride channel (CLC), in OPC differentiation and myelination are not fully understood. The present study demonstrated that CLC-2 may be a positive modulator of OPC differentiation and myelination. Western blotting results revealed that CLC-2 was expressed in both OPCs and OLs. Furthermore, CLC-2 currents (ICLC-2) were recorded in both types of cells. The inhibition of ICLC-2 by GaTx2, a blocker of CLC-2, was demonstrated to be higher in OPCs compared with OLs, indicating that CLC-2 may serve a role in OL differentiation. The results of western blotting and immunofluorescence staining also demonstrated that the expression levels of myelin basic protein were reduced following GaTx2 treatment, indicating that the differentiation of OPCs into OLs was inhibited following CLC-2 inhibition. In addition, following western blot analysis, it was also demonstrated that the protein expression of the myelin proteins yin yang 1, myelin regulatory factor, Smad-interacting protein 1 and sex-determining region Y-box 10 were regulated by CLC-2 inhibition. Taken together, the results of the present study indicate that CLC-2 may be a positive regulator of OPC differentiation and able to contribute to myelin formation and repair in myelin-associated diseases by controlling the number and open state of CLC-2 channels.
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Affiliation(s)
- Xiaolin Hou
- Department of Neurology, General Hospital of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Rui Zhang
- Ningxia Key Laboratory of Cerebrocranial Diseases, Basic Medical School of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Junyan Wang
- Ningxia Key Laboratory of Cerebrocranial Diseases, Basic Medical School of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Yunhong Li
- Ningxia Key Laboratory of Cerebrocranial Diseases, Basic Medical School of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Fan Li
- Ningxia Key Laboratory of Cerebrocranial Diseases, Basic Medical School of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Yan Zhang
- Ningxia Key Laboratory of Cerebrocranial Diseases, Basic Medical School of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Xiaomin Zheng
- Ningxia Key Laboratory of Cerebrocranial Diseases, Basic Medical School of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Ying Shen
- Department of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
| | - Yin Wang
- Ningxia Key Laboratory of Cerebrocranial Diseases, Basic Medical School of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Liang Zhou
- Department of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
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9
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Ruiz M, Bégou M, Launay N, Ranea-Robles P, Bianchi P, López-Erauskin J, Morató L, Guilera C, Petit B, Vaurs-Barriere C, Guéret-Gonthier C, Bonnet-Dupeyron MN, Fourcade S, Auwerx J, Boespflug-Tanguy O, Pujol A. Oxidative stress and mitochondrial dynamics malfunction are linked in Pelizaeus-Merzbacher disease. Brain Pathol 2017; 28:611-630. [PMID: 29027761 PMCID: PMC8028267 DOI: 10.1111/bpa.12571] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 10/06/2017] [Accepted: 10/10/2017] [Indexed: 12/23/2022] Open
Abstract
Pelizaeus‐Merzbacher disease (PMD) is a fatal hypomyelinating disorder characterized by early impairment of motor development, nystagmus, choreoathetotic movements, ataxia and progressive spasticity. PMD is caused by variations in the proteolipid protein gene PLP1, which encodes the two major myelin proteins of the central nervous system, PLP and its spliced isoform DM20, in oligodendrocytes. Large duplications including the entire PLP1 gene are the most frequent causative mutation leading to the classical form of PMD. The Plp1 overexpressing mouse model (PLP‐tg66/66) develops a phenotype very similar to human PMD, with early and severe motor dysfunction and a dramatic decrease in lifespan. The sequence of cellular events that cause neurodegeneration and ultimately death is poorly understood. In this work, we analyzed patient‐derived fibroblasts and spinal cords of the PLP‐tg66/66 mouse model, and identified redox imbalance, with altered antioxidant defense and oxidative damage to several enzymes involved in ATP production, such as glycolytic enzymes, creatine kinase and mitochondrial proteins from the Krebs cycle and oxidative phosphorylation. We also evidenced malfunction of the mitochondria compartment with increased ROS production and depolarization in PMD patient's fibroblasts, which was prevented by the antioxidant N‐acetyl‐cysteine. Finally, we uncovered an impairment of mitochondrial dynamics in patient's fibroblasts which may help explain the ultrastructural abnormalities of mitochondria morphology detected in spinal cords from PLP‐tg66/66 mice. Altogether, these results underscore the link between redox and metabolic homeostasis in myelin diseases, provide insight into the pathophysiology of PMD, and may bear implications for tailored pharmacological intervention.
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Affiliation(s)
- Montserrat Ruiz
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), 08908 L'Hospitalet de Llobregat, Barcelona, Spain.,Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Spain
| | - Mélina Bégou
- Inserm, UMR 1107, NEURO-DOL, F-63001 Clermont-Ferrand, France.,Université Clermont Auvergne, NEURO-DOL, BP 10448, F-63000 Clermont-Ferrand, France
| | - Nathalie Launay
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), 08908 L'Hospitalet de Llobregat, Barcelona, Spain.,Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Spain
| | - Pablo Ranea-Robles
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), 08908 L'Hospitalet de Llobregat, Barcelona, Spain.,Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Spain
| | - Patrizia Bianchi
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), 08908 L'Hospitalet de Llobregat, Barcelona, Spain.,Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Spain
| | - Jone López-Erauskin
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), 08908 L'Hospitalet de Llobregat, Barcelona, Spain.,Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Spain
| | - Laia Morató
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), 08908 L'Hospitalet de Llobregat, Barcelona, Spain.,Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Spain
| | - Cristina Guilera
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), 08908 L'Hospitalet de Llobregat, Barcelona, Spain.,Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Spain
| | - Bérengère Petit
- Université Clermont Auvergne, GReD, BP 10448, F-63000 Clermont-Ferrand, France
| | | | | | | | - Stéphane Fourcade
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), 08908 L'Hospitalet de Llobregat, Barcelona, Spain.,Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Spain
| | - Johan Auwerx
- Laboratory for Integrative and Systems Physiology, École Polytechnique Fédérale de Lausanne, Station 15, CH-1015 Lausanne, Switzerland
| | - Odile Boespflug-Tanguy
- Assistance Publique des Hopitaux de Paris (APHP), Reference Center for Rare Diseases "Leukodystrophies," Child Neurology and Metabolic Disorders Department, Robert Debré University Hospital, Paris, France.,Inserm, Paris Diderot University UMR 1141, DHU PROTECT, Sorbonne Paris-Cite, Robert Debré University Hospital, Paris, France
| | - Aurora Pujol
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), 08908 L'Hospitalet de Llobregat, Barcelona, Spain.,Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Spain.,Institute of Neuropathology, University of Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.,Catalan Institution of Research and Advanced Studies (ICREA), Barcelona, Spain
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10
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Multipotency and therapeutic potential of NG2 cells. Biochem Pharmacol 2017; 141:42-55. [DOI: 10.1016/j.bcp.2017.05.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 05/12/2017] [Indexed: 12/20/2022]
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11
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Cole KLH, Early JJ, Lyons DA. Drug discovery for remyelination and treatment of MS. Glia 2017; 65:1565-1589. [PMID: 28618073 DOI: 10.1002/glia.23166] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/20/2017] [Accepted: 04/24/2017] [Indexed: 12/19/2022]
Abstract
Glia constitute the majority of the cells in our nervous system, yet there are currently no drugs that target glia for the treatment of disease. Given ongoing discoveries of the many roles of glia in numerous diseases of the nervous system, this is likely to change in years to come. Here we focus on the possibility that targeting the oligodendrocyte lineage to promote regeneration of myelin (remyelination) represents a therapeutic strategy for the treatment of the demyelinating disease multiple sclerosis, MS. We discuss how hypothesis driven studies have identified multiple targets and pathways that can be manipulated to promote remyelination in vivo, and how this work has led to the first ever remyelination clinical trials. We also highlight how recent chemical discovery screens have identified a host of small molecule compounds that promote oligodendrocyte differentiation in vitro. Some of these compounds have also been shown to promote myelin regeneration in vivo, with one already being trialled in humans. Promoting oligodendrocyte differentiation and remyelination represents just one potential strategy for the treatment of MS. The pathology of MS is complex, and its complete amelioration may require targeting multiple biological processes in parallel. Therefore, we present an overview of new technologies and models for phenotypic analyses and screening that can be exploited to study complex cell-cell interactions in in vitro and in vivo systems. Such technological platforms will provide insight into fundamental mechanisms and increase capacities for drug-discovery of relevance to glia and currently intractable disorders of the CNS.
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Affiliation(s)
- Katy L H Cole
- Centre for Neuroregeneration, MS Society Centre for Translational Research, Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, United Kingdom
| | - Jason J Early
- Centre for Neuroregeneration, MS Society Centre for Translational Research, Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, United Kingdom
| | - David A Lyons
- Centre for Neuroregeneration, MS Society Centre for Translational Research, Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, United Kingdom
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Zada D, Tovin A, Lerer-Goldshtein T, Appelbaum L. Pharmacological treatment and BBB-targeted genetic therapy for MCT8-dependent hypomyelination in zebrafish. Dis Model Mech 2016; 9:1339-1348. [PMID: 27664134 PMCID: PMC5117236 DOI: 10.1242/dmm.027227] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 09/19/2016] [Indexed: 12/31/2022] Open
Abstract
Hypomyelination is a key symptom of Allan-Herndon-Dudley syndrome (AHDS), a psychomotor retardation associated with mutations in the thyroid-hormone (TH) transporter MCT8 (monocarboxylate transporter 8). AHDS is characterized by severe intellectual deficiency, neuromuscular impairment and brain hypothyroidism. In order to understand the mechanism for TH-dependent hypomyelination, we developed an mct8 mutant (mct8-/-) zebrafish model. The quantification of genetic markers for oligodendrocyte progenitor cells (OPCs) and mature oligodendrocytes revealed reduced differentiation of OPCs into oligodendrocytes in mct8-/- larvae and adults. Live imaging of single glial cells showed that the number of oligodendrocytes and the length of their extensions are reduced, and the number of peripheral Schwann cells is increased, in mct8-/- larvae compared with wild type. Pharmacological analysis showed that TH analogs and clemastine partially rescued the hypomyelination in the CNS of mct8-/- larvae. Intriguingly, triiodothyronine (T3) treatment rescued hypomyelination in mct8-/- embryos before the maturation of the blood-brain barrier (BBB), but did not affect hypomyelination in older larvae. Thus, we expressed Mct8-tagRFP in the endothelial cells of the vascular system and showed that even relatively weak mosaic expression completely rescued hypomyelination in mct8-/- larvae. These results suggest potential pharmacological treatments and BBB-targeted gene therapy that can enhance myelination in AHDS and possibly in other TH-dependent brain disorders.
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Affiliation(s)
- David Zada
- The Faculty of Life Sciences and the Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Adi Tovin
- The Faculty of Life Sciences and the Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Tali Lerer-Goldshtein
- The Faculty of Life Sciences and the Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Lior Appelbaum
- The Faculty of Life Sciences and the Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan 5290002, Israel
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Sarret C, Lemaire JJ, Tonduti D, Sontheimer A, Coste J, Pereira B, Feschet F, Roche B, Boespflug-Tanguy O. Time-course of myelination and atrophy on cerebral imaging in 35 patients with PLP1-related disorders. Dev Med Child Neurol 2016; 58:706-13. [PMID: 26786043 DOI: 10.1111/dmcn.13025] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/08/2015] [Indexed: 11/27/2022]
Abstract
AIM Brain magnetic resonance imaging (MRI) motor development score (MDS) correlations were used to analyze the natural time-course of hypomyelinating PLP1-related disorders (Pelizaeus-Merzbacher disease [PMD] and spastic paraplegia type 2). METHOD Thirty-five male patients (ranging from 0.7-43.5y at the first MRI) with PLP1-related disorder were prospectively followed over 7 years. Patients were classified according to best motor function acquired before 5 years (MDS) into five categories (from PMD0 without motor acquisition to PMD4 with autonomous walking). We determined myelination and atrophy scores and measured corpus callosum area, volume of cerebellum, white matter and grey matter on 63 MRI. RESULTS Age-adjusted multivariate analysis revealed that patients with PMD0-1 had higher-severity atrophy scores and smaller corpus callosum area than did patients with PMD2 and PMD3-4. Myelination score increased until 12 years. There was evidence that the mean myelination differed in frontal white matter, arcuate fibres, and internal capsules among the groups. Most patients showed worsening atrophy (brain, cerebellum, corpus callosum), whereas grey matter and white matter proportions did not change. INTERPRETATION Brain atrophy and myelination of anterior cerebral regions appear to be pertinent biomarkers of motor development. The time-course of inter- and intra-individual cerebral white matter and grey matter atrophy suggests that both oligodendrocytes and neurons are involved in the physiopathology of PLP1-related disorders.
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Affiliation(s)
- Catherine Sarret
- Image-Guided Clinical Neuroscience and Connectomics (IGCNC), Clermont University, University of Auvergne, Clermont-Ferrand, France.,Department of Paediatrics, Clermont-Ferrand University Hospital, Clermont-Ferrand, France
| | - Jean-Jacques Lemaire
- Image-Guided Clinical Neuroscience and Connectomics (IGCNC), Clermont University, University of Auvergne, Clermont-Ferrand, France.,Department of Neurosurgery, Clermont-Ferrand University Hospital, Clermont-Ferrand, France
| | - Davide Tonduti
- Inserm U1141 Paris Diderot Sorbonne University-Paris Cité, DHU PROTECT, Robert Debré Hospital, Paris, France.,Department of Child Neurology, Neurological Institute C. Besta Foundation IRCCS, Milan, Italy
| | - Anna Sontheimer
- Image-Guided Clinical Neuroscience and Connectomics (IGCNC), Clermont University, University of Auvergne, Clermont-Ferrand, France
| | - Jerome Coste
- Image-Guided Clinical Neuroscience and Connectomics (IGCNC), Clermont University, University of Auvergne, Clermont-Ferrand, France
| | - Bruno Pereira
- Image-Guided Clinical Neuroscience and Connectomics (IGCNC), Clermont University, University of Auvergne, Clermont-Ferrand, France.,Biostatistics Unit (DRCI), Clermont-Ferrand University Hospital, Clermont-Ferrand, France
| | - Fabien Feschet
- Image-Guided Clinical Neuroscience and Connectomics (IGCNC), Clermont University, University of Auvergne, Clermont-Ferrand, France
| | - Basile Roche
- Image-Guided Clinical Neuroscience and Connectomics (IGCNC), Clermont University, University of Auvergne, Clermont-Ferrand, France
| | - Odile Boespflug-Tanguy
- Inserm U1141 Paris Diderot Sorbonne University-Paris Cité, DHU PROTECT, Robert Debré Hospital, Paris, France.,Department of Child Neurology and Metabolic Diseases, Leukodystrophies Reference Centre, Robert Debré Hospital, Paris, France
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Darquy S, Moutel G, Lapointe AS, D'Audiffret D, Champagnat J, Guerroui S, Vendeville ML, Boespflug-Tanguy O, Duchange N. Patient/family views on data sharing in rare diseases: study in the European LeukoTreat project. Eur J Hum Genet 2016; 24:338-43. [PMID: 26081642 PMCID: PMC4755367 DOI: 10.1038/ejhg.2015.115] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 04/08/2015] [Accepted: 04/27/2015] [Indexed: 11/08/2022] Open
Abstract
The purpose of this study was to explore patient and family views on the sharing of their medical data in the context of compiling a European leukodystrophies database. A survey questionnaire was delivered with help from referral centers and the European Leukodystrophies Association, and the questionnaires returned were both quantitatively and qualitatively analyzed. This study found that patients/families were strongly in favor of participating. Patients/families hold great hope and trust in the development of this type of research. They have a strong need for information and transparency on database governance, the conditions framing access to data, all research conducted, partnerships with the pharmaceutical industry, and they also need access to results. Our findings bring ethics-driven arguments for a process combining initial broad consent with ongoing information. On both, we propose key item-deliverables to database participants.
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Affiliation(s)
- Sylviane Darquy
- Ethique médicale - EA 4569 – Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, Paris, France
| | - Grégoire Moutel
- Assistance Publique–Hôpitaux de Paris, HEGP-Hôpital Corentin Celton, Unité de Médecine Sociale, Issy-les-Moulineaux, France
| | - Anne-Sophie Lapointe
- Ethique médicale - EA 4569 – Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, Paris, France
| | - Diane D'Audiffret
- Ethique médicale - EA 4569 – Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, Paris, France
| | - Julie Champagnat
- Ethique médicale - EA 4569 – Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, Paris, France
| | - Samia Guerroui
- Clermont Université, Université d'Auvergne, Faculté de médecine, Clermont-Ferrand, France
| | - Marie-Louise Vendeville
- Assistance Publique–Hôpitaux de Paris, Hôpital Robert Debré, Centre de Reference maladies rares « leucodystrophies », Service de Neuropédiatrie et Maladies Métaboliques, Paris, France
| | - Odile Boespflug-Tanguy
- Assistance Publique–Hôpitaux de Paris, Hôpital Robert Debré, Centre de Reference maladies rares « leucodystrophies », Service de Neuropédiatrie et Maladies Métaboliques, Paris, France
- Université Paris Diderot- Sorbonne Paris Cité, DHU Protect, INSERM U 1141, Hôpital Robert Debré, Paris, France
| | - Nathalie Duchange
- Ethique médicale - EA 4569 – Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, Paris, France
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15
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Ferreira MC, Dorboz I, Rodriguez D, Boespflug Tanguy O. Screening for GFAP rearrangements in a cohort of Alexander disease and undetermined leukoencephalopathy patients. Eur J Med Genet 2015. [DOI: 10.1016/j.ejmg.2015.07.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Ethical management in the constitution of a European database for leukodystrophies rare diseases. Eur J Paediatr Neurol 2014; 18:597-603. [PMID: 24786336 DOI: 10.1016/j.ejpn.2014.04.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 02/17/2014] [Accepted: 04/04/2014] [Indexed: 11/24/2022]
Abstract
BACKGROUND The EU LeukoTreat program aims to connect, enlarge and improve existing national databases for leukodystrophies (LDs) and other genetic diseases affecting the white matter of the brain. Ethical issues have been placed high on the agenda by pairing the participating LD expert research teams with experts in medical ethics and LD patient families and associations. The overarching goal is to apply core ethics principles to specific project needs and ensure patient rights and protection in research addressing the context of these rare diseases. AIM This paper looks at how ethical issues were identified and handled at project management level when setting up an ethics committee. METHODS Through a work performed as a co-construction between health professionals, ethics experts, and patient representatives, we expose the major ethical issues identified. RESULTS The committee acts as the forum for tackling specific issues tied to data sharing and patient participation: the thin line between care and research, the need for a charter establishing the commitments binding health professionals and the information items to be delivered. Ongoing feedback on the database, including delivering global results in a broad-audience format, emerged as a key recommendation. Information should be available to all patients in the partner countries developing the database and should be scaled to different patient profiles. CONCLUSION This work led to a number of recommendations for ensuring transparency and optimizing the partnership between scientists and patients.
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17
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GSK3β promotes the differentiation of oligodendrocyte precursor cells via β-catenin-mediated transcriptional regulation. Mol Neurobiol 2014; 50:507-19. [PMID: 24691545 DOI: 10.1007/s12035-014-8678-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 03/11/2014] [Indexed: 12/24/2022]
Abstract
Oligodendrocytes are generated by the differentiation and maturation of oligodendrocyte precursor cells (OPCs). The failure of OPC differentiation is a major cause of demyelinating diseases; thus, identifying the molecular mechanisms that affect OPC differentiation is critical for understanding the myelination process and repairing after demyelination. Although prevailing evidence shows that OPC differentiation is a highly coordinated process controlled by multiple extrinsic and intrinsic factors, such as growth factors, axon signals, and transcription factors, the intracellular signaling in OPC differentiation is still unclear. Here, we showed that glycogen synthase kinase 3β (GSK3β) is an essential positive modulator of OPC differentiation. Both pharmacologic inhibition and knockdown of GSK3β remarkably suppressed OPC differentiation. Terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling assays and Ki67 staining showed that the effect of GSK3β on OPC differentiation was not via cell death. Conversely, activated GSK3β was sufficient to promote OPC differentiation. Our results also demonstrated that the transcription of myelin genes was regulated by GSK3β inhibition, accompanying accumulated nuclear β-catenin, and reduced the expression of transcriptional factors that are relevant to the expression of myelin genes. Taken together, our study identified GSK3β as a profound positive regulator of OPC differentiation, suggesting that GSK3β may contribute to the inefficient regeneration of oligodendrocytes and myelin repair after demyelination.
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18
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Capri Y, Friesema EC, Kersseboom S, Touraine R, Monnier A, Eymard-Pierre E, Des Portes V, De Michele G, Brady AF, Boespflug-Tanguy O, Visser TJ, Vaurs-Barriere C. Relevance of Different Cellular Models in Determining the Effects of Mutations on SLC16A2/MCT8 Thyroid Hormone Transporter Function and Genotype-Phenotype Correlation. Hum Mutat 2013; 34:1018-25. [DOI: 10.1002/humu.22331] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 03/25/2013] [Indexed: 11/06/2022]
Affiliation(s)
- Yline Capri
- INSERM; UMR 1103, CNRS 6293, GReD, Medical school; Clermont-Ferrand France
- APHP; Genetic Department; Robert Debré University Hospital; Paris France
- Université Paris Diderot; Sorbonne Paris Cité, Robert Debré University Hospital; Paris France
| | - Edith C.H. Friesema
- Department of Internal Medicine; Erasmus University Medical Center; Rotterdam The Netherlands
| | - Simone Kersseboom
- Department of Internal Medicine; Erasmus University Medical Center; Rotterdam The Netherlands
| | - Renaud Touraine
- Department of Clinical Chromosomal and Molecular Genetics; CHU St Etienne France
| | - Aurélie Monnier
- INSERM; UMR 1103, CNRS 6293, GReD, Medical school; Clermont-Ferrand France
- Medical Cytogenetic; Clermont-Ferrand University Hospital; Clermont-Ferrand France
| | - Eléonore Eymard-Pierre
- INSERM; UMR 1103, CNRS 6293, GReD, Medical school; Clermont-Ferrand France
- Medical Cytogenetic; Clermont-Ferrand University Hospital; Clermont-Ferrand France
| | - Vincent Des Portes
- Reference Center for Rare Intellectual Disabilities; Neuro-Paediatric Department, Debrousse Hospital; Lyon France
| | - Giusseppe De Michele
- Dipartimento di Scienze Neurologiche; Università di Napoli Federico II; Napoli Italy
| | - Angela F. Brady
- North West Thames Regional Genetics Service, Kennedy-Galton Centre; Northwick Park Hospital; Harrow United-Kingdom
| | - Odile Boespflug-Tanguy
- Université Paris Diderot; Sorbonne Paris Cité, Robert Debré University Hospital; Paris France
- APHP; Reference Center for Rare diseases “Leukodystrophies”, Pediatric Neurology and Metabolic Disorders Department, Robert Debré University Hospital; Paris France
- INSERM U676; Hôpital Robert Debré; Paris France
| | - Theo J. Visser
- Department of Internal Medicine; Erasmus University Medical Center; Rotterdam The Netherlands
| | - Catherine Vaurs-Barriere
- INSERM; UMR 1103, CNRS 6293, GReD, Medical school; Clermont-Ferrand France
- Auvergne University; Medical School; Clermont-Ferrand France
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Abstract
Astrocytes are the predominant glial cell population in the central nervous system (CNS). Once considered only passive scaffolding elements, astrocytes are now recognised as cells playing essential roles in CNS development and function. They control extracellular water and ion homeostasis, provide substrates for energy metabolism, and regulate neurogenesis, myelination and synaptic transmission. Due to these multiple activities astrocytes have been implicated in almost all brain pathologies, contributing to various aspects of disease initiation, progression and resolution. Evidence is emerging that astrocyte dysfunction can be the direct cause of neurodegeneration, as shown in Alexander's disease where myelin degeneration is caused by mutations in the gene encoding the astrocyte-specific cytoskeleton protein glial fibrillary acidic protein. Recent studies point to a primary role for astrocytes in the pathogenesis of other genetic leukodystrophies such as megalencephalic leukoencephalopathy with subcortical cysts and vanishing white matter disease. The aim of this review is to summarize current knowledge of the pathophysiological role of astrocytes focusing on their contribution to the development of the above mentioned leukodystrophies and on new perspectives for the treatment of neurological disorders.
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20
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Building biocompatible hydrogels for tissue engineering of the brain and spinal cord. J Funct Biomater 2012; 3:839-63. [PMID: 24955749 PMCID: PMC4030922 DOI: 10.3390/jfb3040839] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 10/24/2012] [Indexed: 01/07/2023] Open
Abstract
Tissue engineering strategies employing biomaterials have made great progress in the last few decades. However, the tissues of the brain and spinal cord pose unique challenges due to a separate immune system and their nature as soft tissue. Because of this, neural tissue engineering for the brain and spinal cord may require re-establishing biocompatibility and functionality of biomaterials that have previously been successful for tissue engineering in the body. The goal of this review is to briefly describe the distinctive properties of the central nervous system, specifically the neuroimmune response, and to describe the factors which contribute to building polymer hydrogels compatible with this tissue. These factors include polymer chemistry, polymerization and degradation, and the physical and mechanical properties of the hydrogel. By understanding the necessities in making hydrogels biocompatible with tissue of the brain and spinal cord, tissue engineers can then functionalize these materials for repairing and replacing tissue in the central nervous system.
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de Monasterio-Schrader P, Jahn O, Tenzer S, Wichert SP, Patzig J, Werner HB. Systematic approaches to central nervous system myelin. Cell Mol Life Sci 2012; 69:2879-94. [PMID: 22441408 PMCID: PMC11114939 DOI: 10.1007/s00018-012-0958-9] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Accepted: 03/05/2012] [Indexed: 12/11/2022]
Abstract
Rapid signal propagation along vertebrate axons is facilitated by their insulation with myelin, a plasma membrane specialization of glial cells. The recent application of 'omics' approaches to the myelinating cells of the central nervous system, oligodendrocytes, revealed their mRNA signatures, enhanced our understanding of how myelination is regulated, and established that the protein composition of myelin is much more complex than previously thought. This review provides a meta-analysis of the > 1,200 proteins thus far identified by mass spectrometry in biochemically purified central nervous system myelin. Contaminating proteins are surprisingly infrequent according to bioinformatic prediction of subcellular localization and comparison with the transcriptional profile of oligodendrocytes. The integration of datasets also allowed the subcategorization of the myelin proteome into functional groups comprising genes that are coregulated during oligodendroglial differentiation. An unexpectedly large number of myelin-related genes cause-when mutated in humans-hereditary diseases affecting the physiology of the white matter. Systematic approaches to oligodendrocytes and myelin thus provide valuable resources for the molecular dissection of developmental myelination, glia-axonal interactions, leukodystrophies, and demyelinating diseases.
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Affiliation(s)
| | - Olaf Jahn
- Proteomics Group, Max Planck Institute of Experimental Medicine, Göttingen, Germany
- DFG Research Center for Molecular Physiology of the Brain, Göttingen, Germany
| | - Stefan Tenzer
- Institute of Immunology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Sven P. Wichert
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
| | - Julia Patzig
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
| | - Hauke B. Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
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Fogli A, Merle C, Roussel V, Schiffmann R, Ughetto S, Theisen M, Boespflug-Tanguy O. CSF N-glycan profiles to investigate biomarkers in brain developmental disorders: application to leukodystrophies related to eIF2B mutations. PLoS One 2012; 7:e42688. [PMID: 22952606 PMCID: PMC3430715 DOI: 10.1371/journal.pone.0042688] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Accepted: 07/10/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Primary or secondary abnormalities of glycosylation have been reported in various brain diseases. Decreased asialotransferrin to sialotransferrin ratio in cerebrospinal fluid (CSF) is a diagnostic marker of leukodystrophies related to mutations of genes encoding translation initiation factor, EIF2B. We investigated the CSF glycome of eIF2B-mutated patients and age-matched normal individuals in order to further characterize the glycosylation defect for possible use as a biomarker. METHODOLOGY/PRINCIPAL FINDINGS We conducted a differential N-glycan analysis using MALDI-TOF/MS of permethylated N-glycans in CSF and plasma of controls and eIF2B-mutated patients. We found in control CSF that tri-antennary/bisecting and high mannose structures were highly represented in samples obtained between 1 to 5 years of age, whereas fucosylated, sialylated structures were predominant at later age. In CSF, but not in plasma, of eIF2B-mutated patient samples, we found increased relative intensity of bi-antennary structures and decreased tri-antennary/bisecting structures in N-glycan profiles. Four of these structures appeared to be biomarker candidates of glycomic profiles of eIF2B-related disorders. CONCLUSION Our results suggest a dynamic development of normal CSF N-glycan profiles from high mannose type structures to complex sialylated structures that could be correlated with postnatal brain maturation. CSF N-glycome analysis shows relevant quantitative changes associated with eIF2B related disorders. This approach could be applied to other neurological disorders involving developmental gliogenesis/synaptogenesis abnormalities.
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Affiliation(s)
- Anne Fogli
- Laboratoire GReD UMR INSERM U931 CNRS 6247, Faculté de Médecine, Clermont-Ferrand, France.
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Huyghe A, Horzinski L, Hénaut A, Gaillard M, Bertini E, Schiffmann R, Rodriguez D, Dantal Y, Boespflug-Tanguy O, Fogli A. Developmental splicing deregulation in leukodystrophies related to EIF2B mutations. PLoS One 2012; 7:e38264. [PMID: 22737209 PMCID: PMC3380860 DOI: 10.1371/journal.pone.0038264] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Accepted: 05/03/2012] [Indexed: 11/19/2022] Open
Abstract
Leukodystrophies (LD) are rare inherited disorders that primarily affect the white matter (WM) of the central nervous system. The large heterogeneity of LD results from the diversity of the genetically determined defects that interfere with glial cells functions. Astrocytes have been identified as the primary target of LD with cystic myelin breakdown including those related to mutations in the ubiquitous translation initiation factor eIF2B. EIF2B is involved in global protein synthesis and its regulation under normal and stress conditions. Little is known about how eIF2B mutations have a major effect on WM. We performed a transcriptomic analysis using fibroblasts of 10 eIF2B-mutated patients with a severe phenotype and 10 age matched patients with other types of LD in comparison to control fibroblasts. ANOVA was used to identify genes that were statistically significantly differentially expressed at basal state and after ER-stress. The pattern of differentially expressed genes between basal state and ER-stress did not differ significantly among each of the three conditions. However, 70 genes were specifically differentially expressed in eIF2B-mutated fibroblasts whatever the stress conditions tested compared to controls, 96% being under-expressed. Most of these genes were involved in mRNA regulation and mitochondrial metabolism. The 13 most representative genes, including genes belonging to the Heterogeneous Nuclear Ribonucleoprotein (HNRNP) family, described as regulators of splicing events and stability of mRNA, were dysregulated during the development of eIF2B-mutated brains. HNRNPH1, F and C mRNA were over-expressed in foetus but under-expressed in children and adult brains. The abnormal regulation of HNRNP expression in the brain of eIF2B-mutated patients was concomitant with splicing dysregulation of the main genes involved in glial maturation such as PLP1 for oligodendrocytes and GFAP in astrocytes. These findings demonstrate a developmental deregulation of splicing events in glial cells that is related to abnormal production of HNRNP, in eIF2B-mutated brains.
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Affiliation(s)
- Aurélia Huyghe
- Génétique, Reproduction et Développement (GReD) Faculté de Médecine, Clermont-Ferrand, France
- Université de Clermont, UFR Médecine, Clermont-Ferrand, France
| | - Laetitia Horzinski
- Génétique, Reproduction et Développement (GReD) Faculté de Médecine, Clermont-Ferrand, France
- Université de Clermont, UFR Médecine, Clermont-Ferrand, France
| | - Alain Hénaut
- Systématique, Adaptation, Evolution, CNRS - Université Pierre et Marie Curie, Paris, France
| | - Marina Gaillard
- Génétique, Reproduction et Développement (GReD) Faculté de Médecine, Clermont-Ferrand, France
- Université de Clermont, UFR Médecine, Clermont-Ferrand, France
| | - Enrico Bertini
- Division of Neuromuscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Department of Neuroscience, Bambino Gesu’Hospital Instituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rome, Italy
| | - Raphael Schiffmann
- Institute of Metabolic Disease, Baylor Research Institute, Dallas, Texas, United States of America
| | - Diana Rodriguez
- Assistance Publique-Hôpitaux de Paris, Hôpital Armand Trousseau, Service de Neuropédiatrie, Paris, France
- INSERM U676, Hopital Robert Debré, Paris, France
- Université Pierre et Marie Curie, Paris, France
| | - Yann Dantal
- Soluscience, Faculté de Médecine, Clermont-Ferrand, France
| | - Odile Boespflug-Tanguy
- Génétique, Reproduction et Développement (GReD) Faculté de Médecine, Clermont-Ferrand, France
- INSERM U676, Hopital Robert Debré, Paris, France
- Assistance Publique-Hôpitaux de Paris, Hôpital Robert Debré, Service de Neuropédiatrie et Maladies Métaboliques, Paris, France
- Université Paris Diderot, Sorbonne Cité, Paris, France
| | - Anne Fogli
- Génétique, Reproduction et Développement (GReD) Faculté de Médecine, Clermont-Ferrand, France
- Université de Clermont, UFR Médecine, Clermont-Ferrand, France
- Centre Hospitalier Universitaire de Clermont-Ferrand, Service de Biochimie Médicale et Biologie Moléculaire, Clermont-Ferrand, France
- * E-mail:
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Wang E, Cambi F. MicroRNA expression in mouse oligodendrocytes and regulation of proteolipid protein gene expression. J Neurosci Res 2012; 90:1701-12. [PMID: 22504928 DOI: 10.1002/jnr.23055] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 02/19/2012] [Accepted: 02/20/2012] [Indexed: 12/22/2022]
Abstract
Overexpression of the major myelin proteolipid protein (PLP) is detrimental to brain development and function and is the most common cause of Pelizaeus-Merzbacher disease. microRNA (miRNA), small, noncoding RNAs, have been shown to play critical roles in oligodendrocyte lineage. In this study, we sought to investigate whether miRNAs control PLP abundance. To identify candidate miRNAs involved in this regulation, we have examined differentiation-induced changes in the expression of miRNAs in the oligodendroglial cell line Oli-neu and in enhanced green fluorescent protein positive oligodendrocytes ex vivo. We have identified 145 miRNAs that are expressed in oligodendrocyte cell lineage progression. Dicer1 expression decreases in differentiated oligodendrocytes, and knock down of Dicer1 results in changes in miRNAs similar to those associated with differentiation. To identify miRNAs that control the PLP expression, we have selected miRNAs whose expression is lower in differentiated vs. undifferentiated Oli-neu cells and that have one or more binding site(s) in the PLP 3'-untranslated region (3'UTR). The PLP 3'UTR fused to the luciferase gene reduces the activity of the reporter, suggesting that it negatively regulates message stability or translation. Such suppression is relieved by knock down of miR-20a. Overexpression of miR-20a decreases expression of the endogenous PLP in primary oligodendrocytes and of the reporter gene. Deletion or mutation of the putative binding site for miR-20a in the PLP 3'UTR abrogated such effects. Our data indicate that miRNA expression is regulated by Dicer1 levels in differentiated oligodendrocytes and that miR-20a, a component of the cluster that controls oligodendrocyte cell number, regulates PLP gene expression through its 3'UTR.
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Affiliation(s)
- Erming Wang
- Department of Neurology, University of Kentucky, Lexington, Kentucky, USA.
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Combes P, Planche V, Eymard-Pierre E, Sarret C, Rodriguez D, Boespflug-Tanguy O, Vaurs-Barriere C. Relevance of SOX17 variants for hypomyelinating leukodystrophies and congenital anomalies of the kidney and urinary tract (CAKUT). Ann Hum Genet 2012; 76:261-7. [PMID: 22348788 DOI: 10.1111/j.1469-1809.2011.00702.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The SRY-BOX17 gene (SOX17) encodes a transcription factor playing a key role in different developmental processes including endoderm formation, cardiac myogenesis, kidney/urinary development and differentiation of oligodendrocytes, the brain myelinating cells. In a candidate gene approach, we analyzed the SOX17 gene in hypomyelinating leukodystrophies (HL) characterized by a permanent deficit in the amount of central nervous system myelin. Five genes are involved in the aetiology of HL but 40% of HL remains without known genetic origin (UHL). New sequence variations in SOX17 were identified but all correspond to nonpathogenic variants, suggesting that SOX17 is not involved in UHL phenotype. In one patient, we identified the c.775T>A (p.Tyr259Asn) variation already reported as causative of congenital kidney and urinary tract abnormalities (CAKUT). Nevertheless, since our patient did not present such a phenotype, we propose that this variant may alternatively represent an "at-risk" allele for CAKUT rather than a causative allele. This observation strengthens the idea that caution must be taken when linking genetic variation to disease, especially in discrete phenotypes such as CAKUT.
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Affiliation(s)
- Patricia Combes
- INSERM, UMR, CNRS, GReD, Medical School, Clermont-Ferrand, France
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26
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Castelvetri LC, Givogri MI, Zhu H, Smith B, Lopez-Rosas A, Qiu X, van Breemen R, Bongarzone E. Axonopathy is a compounding factor in the pathogenesis of Krabbe disease. Acta Neuropathol 2011; 122:35-48. [PMID: 21373782 PMCID: PMC3690521 DOI: 10.1007/s00401-011-0814-2] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Revised: 02/12/2011] [Accepted: 02/24/2011] [Indexed: 10/18/2022]
Abstract
Loss-of-function of the lysosomal enzyme galactosyl-ceramidase causes the accumulation of the lipid raft-associated sphingolipid psychosine, the disruption of postnatal myelination, neurodegeneration and early death in most cases of infantile Krabbe disease. This work presents a first study towards understanding the progression of axonal defects in this disease using the Twitcher mutant mouse. Axonal swellings were detected in axons within the mutant spinal cord as early as 1 week after birth. As the disease progressed, more axonopathic profiles were found in other regions of the nervous system, including peripheral nerves and various brain areas. Isolated mutant neurons recapitulated axonal and neuronal defects in the absence of mutant myelinating glia, suggesting an autonomous neuronal defect. Psychosine was sufficient to induce axonal defects and cell death in cultures of acutely isolated neurons. Interestingly, axonopathy in young Twitcher mice occurred in the absence of demyelination and of neuronal apoptosis. Neuronal damage occurred at later stages, when mutant mice were moribund and demyelinated. Altogether, these findings suggest a progressive dying-back neuronal dysfunction in Twitcher mutants.
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Affiliation(s)
- Ludovico Cantuti Castelvetri
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois, Chicago. 808 South Wood Street. MC512. Chicago, IL. 60612
| | - Maria Irene Givogri
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois, Chicago. 808 South Wood Street. MC512. Chicago, IL. 60612
| | - Hongling Zhu
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois, Chicago. 808 South Wood Street. MC512. Chicago, IL. 60612
| | - Benjamin Smith
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois, Chicago. 808 South Wood Street. MC512. Chicago, IL. 60612
| | - Aurora Lopez-Rosas
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois, Chicago. 808 South Wood Street. MC512. Chicago, IL. 60612
| | - Xi Qiu
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois, Chicago, 833 South Wood Street. MC 874
| | - Richard van Breemen
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois, Chicago, 833 South Wood Street. MC 874
| | - Ernesto Bongarzone
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois, Chicago. 808 South Wood Street. MC512. Chicago, IL. 60612
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Abstract
Leukodystrophies (LDs) refer to a group on inherited diseases in which molecular abnormalities of glial cells are responsible for exclusive or predominant defects in myelin formation and/or maintenance within the central and, sometimes, the peripheral nervous system. For three of them [X-linked adrenoleukodystrophy (X-ALD), metachromatic (MLD) and globoid cell LDs], a gene therapy strategy aiming at transferring the disease gene into autologous hematopoietic stem cells (HSCs) using lentiviral vectors has been developed and has already entered into the clinics for X-ALD and MLD. Long-term follow-up has shown that HSCs gene therapy can arrest the devastating progression of X-ALD. Brain gene therapy relying upon intracerebral injections of adeno-associated vectors is also envisaged for MLD. The development of new gene therapy viral vectors allowing targeting of the disease gene into oligodendrocytes or astrocytes should soon benefit other forms of LDs.
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Affiliation(s)
- Alessandra Biffi
- San Raffaele Telethon Institute for Gene Therapy (HSR-TIGET), Division of Regenerative Medicine, Stem Cells and Gene Therapy, San Raffaele Scientific Institute, Milan, Italy
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Neurodegenerative disorder related to AIMP1/p43 mutation is not a PMLD. Am J Hum Genet 2011; 88:392-3; author reply 393-5. [PMID: 21397067 DOI: 10.1016/j.ajhg.2010.12.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 12/21/2010] [Accepted: 12/21/2010] [Indexed: 11/23/2022] Open
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Abstract
The myelin sheath is an essential component of the vertebrate nervous system, and its disruption causes numerous diseases, including multiple sclerosis (MS), and neurodegeneration. Although we understand a great deal about the early development of the glial cells that make myelin (Schwann cells in the peripheral nervous system and oligodendrocytes in the central nervous system), we know much less about the cellular and molecular mechanisms that regulate the later stages of differentiation that orchestrate myelin formation. Over the past decade, the zebrafish has been employed as a model with which to dissect the development of myelinated axons. Forward genetic screens have revealed new genes essential for myelination, as well as new roles for genes previously implicated in myelinated axon formation in other systems. High-resolution in vivo imaging in zebrafish has also begun to illuminate novel cell behaviors during myelinating glial cell development. Here we review the contribution of zebrafish research to our understanding of myelinated axon formation to date. We also describe and discuss many of the methodologies used in these studies and preview future endeavors that will ensure that the zebrafish remains at the cutting edge of this important area of research.
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Affiliation(s)
- Tim Czopka
- Centre for Neuroregeneration, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, UK
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Elevated phosphatidylinositol 3,4,5-trisphosphate in glia triggers cell-autonomous membrane wrapping and myelination. J Neurosci 2010; 30:8953-64. [PMID: 20592216 DOI: 10.1523/jneurosci.0219-10.2010] [Citation(s) in RCA: 253] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
In the developing nervous system, constitutive activation of the AKT/mTOR (mammalian target of rapamycin) pathway in myelinating glial cells is associated with hypermyelination of the brain, but is reportedly insufficient to drive myelination by Schwann cells. We have hypothesized that it requires additional mechanisms downstream of NRG1/ErbB signaling to trigger myelination in the peripheral nervous system. Here, we demonstrate that elevated levels of phosphatidylinositol 3,4,5-trisphosphate (PIP3) have developmental effects on both oligodendrocytes and Schwann cells. By generating conditional mouse mutants, we found that Pten-deficient Schwann cells are enhanced in number and can sort and myelinate axons with calibers well below 1 microm. Unexpectedly, mutant glial cells also spirally enwrap C-fiber axons within Remak bundles and even collagen fibrils, which lack any membrane surface. Importantly, PIP3-dependent hypermyelination of central axons, which is observed when targeting Pten in oligodendrocytes, can also be induced after tamoxifen-mediated Cre recombination in adult mice. We conclude that it requires distinct PIP3 effector mechanisms to trigger axonal wrapping. That myelin synthesis is not restricted to early development but can occur later in life is relevant to developmental disorders and myelin disease.
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Werner HB, Jahn O. Myelin matters: proteomic insights into white matter disorders. Expert Rev Proteomics 2010; 7:159-64. [PMID: 20377380 DOI: 10.1586/epr.09.105] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Sarret C, Combes P, Micheau P, Gelot A, Boespflug-Tanguy O, Vaurs-Barriere C. Novel neuronal proteolipid protein isoforms encoded by the human myelin proteolipid protein 1 gene. Neuroscience 2009; 166:522-38. [PMID: 20036320 DOI: 10.1016/j.neuroscience.2009.12.047] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 12/17/2009] [Accepted: 12/17/2009] [Indexed: 01/21/2023]
Abstract
The human myelin proteolipid protein 1 gene (hPLP1), which encodes the major structural myelin proteins of the central nervous system (CNS), is classically described as expressed in the oligodendrocytes, the CNS myelinating cells. We identified two new exons in the intron 1 of the hPLP1 gene that lead to the expression of additional mRNA and protein isoforms mainly expressed in neurons instead of oligodendrocytes. Those novel neuronal PLP isoforms are detected as soon as human fetal development and their concomitant expression is specific of the human species. As classical PLP proteins, the novel protein isoforms seem to be addressed to the plasma membrane. These results suggest for the first time that PLP may have functions in humans not only in oligodendrocytes but also in neurons and could be implicated in axono-glial communication. Moreover, this neuronal expression of the hPLP1 gene might explain the neuronal dysfunctions in patients carrying hPLP1 gene mutations.
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Affiliation(s)
- C Sarret
- Faculté de Médecine, Institut National de la Santé et de la Recherche Médicale, U931, GReD CNRS 6247, 63000 Clermont-Ferrand, France
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Labauge P, Horzinski L, Ayrignac X, Blanc P, Vukusic S, Rodriguez D, Mauguiere F, Peter L, Goizet C, Bouhour F, Denier C, Confavreux C, Obadia M, Blanc F, de Sèze J, Fogli A, Boespflug-Tanguy O. Natural history of adult-onset eIF2B-related disorders: a multi-centric survey of 16 cases. Brain 2009; 132:2161-9. [PMID: 19625339 DOI: 10.1093/brain/awp171] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Mutations in one of the five eukaryotic initiation factor 2B genes (EIF2B1-5) were first described in childhood ataxia with cerebral hypomyelination--vanishing white matter syndrome. The syndrome is characterized by (i) cerebellar and pyramidal signs in children aged 2-5 years; (ii) extensive cavitating leucoencephalopathy; and (iii) episodes of rapid deterioration following stress. Since then a broad clinical spectrum from congenital to adult-onset forms has been reported, leading to the concept of eIF2B-related disorders. Our aim was to describe clinical and brain magnetic resonance imaging characteristics, genetic findings and natural history of patients with adult-onset eIF2B-related disorders (after age 16). The inclusion criteria were based on the presence of eIF2B mutations and a disease onset after the age of 16 years. One patient with an asymptomatic diagnosis (age 16 years) was also included. Clinical and magnetic resonance findings were retrospectively recorded in all patients. All patients were examined to assess clinical evolution, using functional, pyramidal, cerebellar and cognitive scales. This multi-centric study included 16 patients from 14 families. A sex ratio imbalance was noted (male/female = 3/13). The mean age of onset was 31.1 years (range 16-62). Initial symptoms were neurologic (n = 11), psychiatric (n = 2) and ovarian failure (n = 2). Onset of the symptoms was linked to a precipitating factor in 13% of cases that included minor head trauma and delivery. During follow-up (mean: 11.2 years, range 2-22 years) 12.5% of the patients died. Of the 14 survivors, 62% showed a decline in their cognitive functions, and 79% were severely handicapped or bedridden. One case remained asymptomatic. Stress worsened clinical symptoms in 38% of the patients. Magnetic resonance imaging findings consist of constant cerebral atrophy, extensive cystic leucoencephalopathy (81%), corpus callosum (69%) and cerebellar (38%) T2-weighted hyperintensities. All families except one showed mutations in the EIF2B5 gene. The recurrent p.Arg113His-eIF2Bepsilon mutation was found in 79% of the 14 eIF2B-mutated families, mainly at a homozygous state. The family with a mutation in EIF2B2 had the relatively prevalent p.Glu213Gly mutation. eIF2B-related disorder is probably underestimated as an adult-onset inherited leucoencephalopathy. In this late-onset form, presentation ranges from neurologic symptoms to psychiatric manifestations or primary ovarian failure. Cerebral atrophy is constant, whereas the typical vanishing of the white matter can be absent. Functional and/or cognitive prognosis remains severe. Molecular diagnosis is facilitated for these forms by the screening of the two recurrent p.Arg113His-eIF2Bepsilon and p.Glu213Gly-eIF2Bbeta mutations, positive in 86% of cases.
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Affiliation(s)
- Pierre Labauge
- CHU Nîmes, Service de neurologie, Hôpital Caremeau, place du Professeur-Debré, 30029 Nîmes cedex 4, France.
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Myelin proteomics: molecular anatomy of an insulating sheath. Mol Neurobiol 2009; 40:55-72. [PMID: 19452287 PMCID: PMC2758371 DOI: 10.1007/s12035-009-8071-2] [Citation(s) in RCA: 218] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2009] [Accepted: 04/14/2009] [Indexed: 12/12/2022]
Abstract
Fast-transmitting vertebrate axons are electrically insulated with multiple layers of nonconductive plasma membrane of glial cell origin, termed myelin. The myelin membrane is dominated by lipids, and its protein composition has historically been viewed to be of very low complexity. In this review, we discuss an updated reference compendium of 342 proteins associated with central nervous system myelin that represents a valuable resource for analyzing myelin biogenesis and white matter homeostasis. Cataloging the myelin proteome has been made possible by technical advances in the separation and mass spectrometric detection of proteins, also referred to as proteomics. This led to the identification of a large number of novel myelin-associated proteins, many of which represent low abundant components involved in catalytic activities, the cytoskeleton, vesicular trafficking, or cell adhesion. By mass spectrometry-based quantification, proteolipid protein and myelin basic protein constitute 17% and 8% of total myelin protein, respectively, suggesting that their abundance was previously overestimated. As the biochemical profile of myelin-associated proteins is highly reproducible, differential proteome analyses can be applied to material isolated from patients or animal models of myelin-related diseases such as multiple sclerosis and leukodystrophies.
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Vaurs-Barrière C, Deville M, Sarret C, Giraud G, Des Portes V, Prats-Viñas JM, De Michele G, Dan B, Brady AF, Boespflug-Tanguy O, Touraine R. Pelizaeus-Merzbacher-Like disease presentation of MCT8 mutated male subjects. Ann Neurol 2009; 65:114-8. [DOI: 10.1002/ana.21579] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
Remyelination involves reinvesting demyelinated axons with new myelin sheaths. In stark contrast to the situation that follows loss of neurons or axonal damage, remyelination in the CNS can be a highly effective regenerative process. It is mediated by a population of precursor cells called oligodendrocyte precursor cells (OPCs), which are widely distributed throughout the adult CNS. However, despite its efficiency in experimental models and in some clinical diseases, remyelination is often inadequate in demyelinating diseases such as multiple sclerosis (MS), the most common demyelinating disease and a cause of neurological disability in young adults. The failure of remyelination has profound consequences for the health of axons, the progressive and irreversible loss of which accounts for the progressive nature of these diseases. The mechanisms of remyelination therefore provide critical clues for regeneration biologists that help them to determine why remyelination fails in MS and in other demyelinating diseases and how it might be enhanced therapeutically.
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