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Bekku Y, Zotter B, You C, Piehler J, Leonard WJ, Salzer JL. Glia trigger endocytic clearance of axonal proteins to promote rodent myelination. Dev Cell 2024; 59:627-644.e10. [PMID: 38309265 PMCID: PMC11089820 DOI: 10.1016/j.devcel.2024.01.008] [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: 03/05/2023] [Revised: 09/09/2023] [Accepted: 01/12/2024] [Indexed: 02/05/2024]
Abstract
Axons undergo striking changes in their content and distribution of cell adhesion molecules (CAMs) and ion channels during myelination that underlies the switch from continuous to saltatory conduction. These changes include the removal of a large cohort of uniformly distributed CAMs that mediate initial axon-Schwann cell interactions and their replacement by a subset of CAMs that mediate domain-specific interactions of myelinated fibers. Here, using rodent models, we examine the mechanisms and significance of this removal of axonal CAMs. We show that Schwann cells just prior to myelination locally activate clathrin-mediated endocytosis (CME) in axons, thereby driving clearance of a broad array of axonal CAMs. CAMs engineered to resist endocytosis are persistently expressed along the axon and delay both PNS and CNS myelination. Thus, glia non-autonomously activate CME in axons to downregulate axonal CAMs and presumptively axo-glial adhesion. This promotes the transition from ensheathment to myelination while simultaneously sculpting the formation of axonal domains.
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Affiliation(s)
- Yoko Bekku
- Neuroscience Institute, New York University Langone Medical Center, New York, NY 10016, USA.
| | - Brendan Zotter
- Neuroscience Institute, New York University Langone Medical Center, New York, NY 10016, USA
| | - Changjiang You
- Department of Biology/Chemistry and Center for Cellular Nanoanalytics, Osnabrück University, Barbarastr. 11, 49076 Osnabrück, Germany
| | - Jacob Piehler
- Department of Biology/Chemistry and Center for Cellular Nanoanalytics, Osnabrück University, Barbarastr. 11, 49076 Osnabrück, Germany
| | - Warren J Leonard
- Laboratory of Molecular Immunology and Immunology Center, National Heart, Lung, and Blood Institute, National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - James L Salzer
- Neuroscience Institute, New York University Langone Medical Center, New York, NY 10016, USA.
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2
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Klotz L, Antel J, Kuhlmann T. Inflammation in multiple sclerosis: consequences for remyelination and disease progression. Nat Rev Neurol 2023; 19:305-320. [PMID: 37059811 DOI: 10.1038/s41582-023-00801-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/15/2023] [Indexed: 04/16/2023]
Abstract
Despite the large number of immunomodulatory or immunosuppressive treatments available to treat relapsing-remitting multiple sclerosis (MS), treatment of the progressive phase of the disease has not yet been achieved. This lack of successful treatment approaches is caused by our poor understanding of the mechanisms driving disease progression. Emerging concepts suggest that a combination of persisting focal and diffuse inflammation within the CNS and a gradual failure of compensatory mechanisms, including remyelination, result in disease progression. Therefore, promotion of remyelination presents a promising intervention approach. However, despite our increasing knowledge regarding the cellular and molecular mechanisms regulating remyelination in animal models, therapeutic increases in remyelination remain an unmet need in MS, which suggests that mechanisms of remyelination and remyelination failure differ fundamentally between humans and demyelinating animal models. New and emerging technologies now allow us to investigate the cellular and molecular mechanisms underlying remyelination failure in human tissue samples in an unprecedented way. The aim of this Review is to summarize our current knowledge regarding mechanisms of remyelination and remyelination failure in MS and in animal models of the disease, identify open questions, challenge existing concepts, and discuss strategies to overcome the translational roadblock in the field of remyelination-promoting therapies.
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Affiliation(s)
- Luisa Klotz
- Department of Neurology with Institute of Translational Neurology, University Hospital Münster, Münster, Germany
| | - Jack Antel
- Neuroimmunology Unit, Montreal Neurological Institute, McGill University, Québec, Canada
| | - Tanja Kuhlmann
- Neuroimmunology Unit, Montreal Neurological Institute, McGill University, Québec, Canada.
- Institute of Neuropathology, University Hospital Münster, Münster, Germany.
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3
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Eve M, Gandawijaya J, Yang L, Oguro-Ando A. Neuronal Cell Adhesion Molecules May Mediate Neuroinflammation in Autism Spectrum Disorder. Front Psychiatry 2022; 13:842755. [PMID: 35492721 PMCID: PMC9051034 DOI: 10.3389/fpsyt.2022.842755] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 02/15/2022] [Indexed: 12/15/2022] Open
Abstract
Autism spectrum disorder (ASD) is a complex neurodevelopmental condition characterized by restrictive and repetitive behaviors, alongside deficits in social interaction and communication. The etiology of ASD is largely unknown but is strongly linked to genetic variants in neuronal cell adhesion molecules (CAMs), cell-surface proteins that have important roles in neurodevelopment. A combination of environmental and genetic factors are believed to contribute to ASD pathogenesis. Inflammation in ASD has been identified as one of these factors, demonstrated through the presence of proinflammatory cytokines, maternal immune activation, and activation of glial cells in ASD brains. Glial cells are the main source of cytokines within the brain and, therefore, their activity is vital in mediating inflammation in the central nervous system. However, it is unclear whether the aforementioned neuronal CAMs are involved in modulating neuroimmune signaling or glial behavior. This review aims to address the largely unexplored role that neuronal CAMs may play in mediating inflammatory cascades that underpin neuroinflammation in ASD, primarily focusing on the Notch, nuclear factor-κB (NF-κB), and mitogen-activated protein kinase (MAPK) cascades. We will also evaluate the available evidence on how neuronal CAMs may influence glial activity associated with inflammation. This is important when considering the impact of environmental factors and inflammatory responses on ASD development. In particular, neural CAM1 (NCAM1) can regulate NF-κB transcription in neurons, directly altering proinflammatory signaling. Additionally, NCAM1 and contactin-1 appear to mediate astrocyte and oligodendrocyte precursor proliferation which can alter the neuroimmune response. Importantly, although this review highlights the limited information available, there is evidence of a neuronal CAM regulatory role in inflammatory signaling. This warrants further investigation into the role other neuronal CAM family members may have in mediating inflammatory cascades and would advance our understanding of how neuroinflammation can contribute to ASD pathology.
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Affiliation(s)
- Madeline Eve
- University of Exeter Medical School, University of Exeter, Exeter, United Kingdom
| | - Josan Gandawijaya
- University of Exeter Medical School, University of Exeter, Exeter, United Kingdom
| | - Liming Yang
- University of Exeter Medical School, University of Exeter, Exeter, United Kingdom
| | - Asami Oguro-Ando
- University of Exeter Medical School, University of Exeter, Exeter, United Kingdom
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4
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Shaaban S, Zarrouk A, Vervandier-Fasseur D, S.Al-Faiyz Y, El-Sawy H, Althagafi I, Andreoletti P, Cherkaoui-Malki M. Cytoprotective organoselenium compounds for oligodendrocytes. ARAB J CHEM 2021. [DOI: 10.1016/j.arabjc.2021.103051] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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5
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Ma G, Liu C, Hashim J, Conley G, Morriss N, Meehan WP, Qiu J, Mannix R. Memantine Mitigates Oligodendrocyte Damage after Repetitive Mild Traumatic Brain Injury. Neuroscience 2019; 421:152-161. [DOI: 10.1016/j.neuroscience.2019.10.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 10/07/2019] [Accepted: 10/08/2019] [Indexed: 12/14/2022]
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6
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Teo RTY, Ferrari Bardile C, Tay YL, Yusof NABM, Kreidy CA, Tan LJ, Pouladi MA. Impaired Remyelination in a Mouse Model of Huntington Disease. Mol Neurobiol 2019; 56:6873-6882. [PMID: 30937636 DOI: 10.1007/s12035-019-1579-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 03/20/2019] [Indexed: 01/26/2023]
Abstract
White matter (WM) abnormalities are a well-established feature of Huntington disease (HD), although their nature is not fully understood. Here, we asked whether remyelination as a measure of WM plasticity is impaired in a model of HD. Using the cuprizone assay, we examined demyelination and remyelination responses in YAC128 HD mice. Treatment with 0.2% cuprizone (CPZ) for 6 weeks resulted in significant reduction in mature (GSTπ-positive) oligodendrocyte counts and FluoroMyelin staining in the corpus callosum, leading to similar demyelination states in YAC128 and wild-type (WT) mice. Six weeks following cessation of CPZ, we observed robust remyelination in WT mice as indicated by an increase in mature oligodendrocyte counts and FluoroMyelin staining. In contrast, YAC128 mice exhibited an impaired remyelination response. The increase in mature oligodendrocyte counts in YAC128 HD mice following CPZ cessation was lower than that of WT. Furthermore, there was no increase in FluoroMyelin staining compared to the demyelinated state in YAC128 mice. We confirmed these findings using electron microscopy where the CPZ-induced reduction in myelinated axons was reversed following CPZ cessation in WT but not YAC128 mice. Our findings demonstrate that remyelination is impaired in YAC128 mice and suggest that WM plasticity may be compromised in HD.
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Affiliation(s)
- Roy Tang Yi Teo
- Translational Laboratory in Genetic Medicine, Agency for Science, Technology and Research, Singapore (A*STAR), 8A Biomedical Grove, Immunos, Level 5, Singapore, 138648, Singapore
| | - Costanza Ferrari Bardile
- Translational Laboratory in Genetic Medicine, Agency for Science, Technology and Research, Singapore (A*STAR), 8A Biomedical Grove, Immunos, Level 5, Singapore, 138648, Singapore
| | - Yi Lin Tay
- Translational Laboratory in Genetic Medicine, Agency for Science, Technology and Research, Singapore (A*STAR), 8A Biomedical Grove, Immunos, Level 5, Singapore, 138648, Singapore
| | - Nur Amirah Binte Mohammad Yusof
- Translational Laboratory in Genetic Medicine, Agency for Science, Technology and Research, Singapore (A*STAR), 8A Biomedical Grove, Immunos, Level 5, Singapore, 138648, Singapore
| | - Charbel A Kreidy
- Translational Laboratory in Genetic Medicine, Agency for Science, Technology and Research, Singapore (A*STAR), 8A Biomedical Grove, Immunos, Level 5, Singapore, 138648, Singapore
| | - Liang Juin Tan
- Translational Laboratory in Genetic Medicine, Agency for Science, Technology and Research, Singapore (A*STAR), 8A Biomedical Grove, Immunos, Level 5, Singapore, 138648, Singapore
| | - Mahmoud A Pouladi
- Translational Laboratory in Genetic Medicine, Agency for Science, Technology and Research, Singapore (A*STAR), 8A Biomedical Grove, Immunos, Level 5, Singapore, 138648, Singapore.
- Department of Medicine, National University of Singapore, Singapore, 117597, Singapore.
- Department of Physiology, National University of Singapore, Singapore, 117597, Singapore.
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7
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Hiratsuka D, Furube E, Taguchi K, Tanaka M, Morita M, Miyata S. Remyelination in the medulla oblongata of adult mouse brain during experimental autoimmune encephalomyelitis. J Neuroimmunol 2018; 319:41-54. [DOI: 10.1016/j.jneuroim.2018.03.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 03/10/2018] [Accepted: 03/23/2018] [Indexed: 10/17/2022]
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8
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Cytoprotective and antioxidant properties of organic selenides for the myelin-forming cells, oligodendrocytes. Bioorg Chem 2018; 80:43-56. [PMID: 29864687 DOI: 10.1016/j.bioorg.2018.05.019] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 05/16/2018] [Accepted: 05/20/2018] [Indexed: 12/25/2022]
Abstract
Here a new series of twenty-one organoselenides, of potential protective activity, were synthesized and tested for their intrinsic cytotoxicity, anti-apoptotic and antioxidant capacities in oligodendrocytes. Most of the organoselenides were able to decrease the ROS levels, revealing antioxidant properties. Compounds 5b and 7b showed a high glutathione peroxidase (GPx)-like activities, which were 1.5 folds more active than ebselen. Remarkably, compound 5a diminished the formation of the oligodendrocytes SubG1 peak in a concentration-dependent manner, indicating its anti-apoptotic properties. Furthermore, based on the SwissADME web interface, we performed an in-silico structure-activity relationship to explore the drug-likeness of these organoselenides, predicting the pharmacokinetic parameters for compounds of interest that could cross the blood-brain barrier. Collectively, we present new organoselenide compounds with cytoprotective and antioxidant properties that can be considered as promising drug candidates for myelin diseases.
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9
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Farnsworth B, Peuckert C, Zimmermann B, Jazin E, Kettunen P, Emilsson LS. Gene Expression of Quaking in Sporadic Alzheimer's Disease Patients is Both Upregulated and Related to Expression Levels of Genes Involved in Amyloid Plaque and Neurofibrillary Tangle Formation. J Alzheimers Dis 2018; 53:209-19. [PMID: 27163826 PMCID: PMC4942724 DOI: 10.3233/jad-160160] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Quaking (QKI) is a gene exclusively expressed within glial cells. QKI has previously been implicated in various neurological disorders and diseases, including Alzheimer’s disease (AD), a condition for which increasing evidence suggests a central role of glia cells. The objective of the present study was to investigate the expression levels of QKI and three QKI isoforms (QKI5, QKI6, and QKI7) in AD. Genes that have previously been related to the ontogeny and progression of AD, specifically APP, PSEN1, PSEN2, and MAPT, were also investigated. A real-time PCR assay of 123 samples from human postmortem sporadic AD patients and control brains was performed. The expression values were analyzed with an analysis of covariance model and subsequent multiple regressions to explore the possibility of related expression values between QKI, QKI isoforms, and AD-related genes. Further, the sequences of AD-related genes were analyzed for the presence of QKI binding domains. QKI and all measured QKI isoforms were found to be significantly upregulated in AD samples, relative to control samples. However, APP, PSEN1, PSEN2, and MAPT were not found to be significantly different. QKI and QKI isoforms were found to be predictive for the variance of APP, PSEN1, PSEN2, and MAPT, and putative QKI binding sites suggests an interaction with QKI. Overall, these results implicate a possible role of QKI in AD, although the exact mechanism by which this occurs remains to be uncovered.
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Affiliation(s)
- Bryn Farnsworth
- Department of Evolution and Development, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Christiane Peuckert
- Department of Neuroscience, Uppsala Biomedical Centre, Uppsala University, Uppsala, Sweden
| | - Bettina Zimmermann
- Department of Evolution and Development, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Elena Jazin
- Department of Evolution and Development, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Petronella Kettunen
- Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Department of Neuropathology, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Lina Sors Emilsson
- Department of Evolution and Development, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
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10
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Tagliabue E, Pouvreau T, Eybrard S, Meyer F, Louilot A. Dopaminergic responses in the core part of the nucleus accumbens to subcutaneous MK801 administration are increased following postnatal transient blockade of the prefrontal cortex. Behav Brain Res 2017; 335:191-198. [PMID: 28823626 DOI: 10.1016/j.bbr.2017.08.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 08/07/2017] [Accepted: 08/12/2017] [Indexed: 12/24/2022]
Abstract
Schizophrenia is a complex and devastating neuropsychiatric disease thought to result from impaired connectivity between several integrative regions, stemming from developmental failures. In particular, the left prefrontal cortex of schizophrenia patients seems to be targeted by such early developmental disturbances. Data obtained over the last three decades support the hypothesis of a dopaminergic dysfunction in schizophrenia. Striatal dopaminergic dysregulation in schizophrenia may result from a dysconnection between the prefrontal cortex and the striatum (dorsal and ventral) involving glutamatergic N-methyl-d-aspartate (NMDA) receptors. In the context of animal modeling of the pathophysiology of schizophrenia, the present study was designed to investigate the effects of MK 801 (dizocilpine) on locomotor activity and dopaminergic responses in the left core part of the nucleus accumbens (ventral striatum) in adult rats following neonatal tetrodotoxin inactivation of the left prefrontal cortex (infralimbic/prelimbic region) at postnatal day 8. Dopaminergic variations were recorded in the nucleus accumbens by means of in vivo voltammetry in freely moving adult animals. Following MK 801 administration, and in comparison to control (PBS) animals, animals microinjected with tetrodotoxin display locomotor hyperactivity and increased extracellular dopamine levels in the core part of the nucleus accumbens. These findings suggest neonatal functional inactivation of the prefrontal cortex may lead to a dysregulation of dopamine release in the core part of the nucleus accumbens involving NMDA receptors. The results obtained may provide new insight into the involvement of NMDA receptors in the pathophysiology of schizophrenia and suggest that future studies should look carefully at the core of the nucleus accumbens.
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Affiliation(s)
- Emmanuelle Tagliabue
- University of Strasbourg, INSERM U 1114, Faculty of Medicine, FMTS, Strasbourg, France
| | - Tiphaine Pouvreau
- University of Strasbourg, INSERM U 1114, Faculty of Medicine, FMTS, Strasbourg, France
| | - Séverine Eybrard
- University of Strasbourg, INSERM U 1114, Faculty of Medicine, FMTS, Strasbourg, France
| | - Francisca Meyer
- Department of Molecular Animal Physiology, Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Alain Louilot
- University of Strasbourg, INSERM U 1114, Faculty of Medicine, FMTS, Strasbourg, France.
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11
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Rasmussen JM, Kruggel F, Gilmore JH, Styner M, Entringer S, Consing KNZ, Potkin SG, Wadhwa PD, Buss C. A novel maturation index based on neonatal diffusion tensor imaging reflects typical perinatal white matter development in humans. Int J Dev Neurosci 2016; 56:42-51. [PMID: 27988340 DOI: 10.1016/j.ijdevneu.2016.12.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 12/12/2016] [Accepted: 12/12/2016] [Indexed: 12/15/2022] Open
Abstract
Human birth presents an abrupt transition from intrauterine to extrauterine life. Here we introduce a novel Maturation Index (MI) that considers the relative importance of gestational age at birth and postnatal age at scan in a General Linear Model. The MI is then applied to Diffusion Tensor Imaging (DTI) in newborns for characterizing typical white matter development in neonates. DTI was performed cross-sectionally in 47 neonates (gestational age at birth=39.1±1.6 weeks [GA], postnatal age at scan=25.5±12.2days [SA]). Radial diffusivity (RD), axial diffusivity (AD) and fractional anisotropy (FA) along 27 white matter fiber tracts were considered. The MI was used to characterize inflection in maturation at the time of birth using GLM estimated rates of change before and after birth. It is proposed that the sign (positive versus negative) of MI reflects the period of greatest maturation rate. Two general patterns emerged from the MI analysis. First, RD and AD (but not FA) had positive MI on average across the whole brain (average MIAD=0.31±0.42, average MIRD=0.22±0.34). Second, significant regions of negative MI in RD and FA (but not AD) were observed in the inferior corticospinal regions, areas known to myelinate early. Observations using the proposed method are consistent with proposed models of the white matter maturation process in which pre-myelination is described by changes in AD and RD due to oligodendrocyte proliferation while true myelination is characterized by changes in RD and FA due to myelin formation.
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Affiliation(s)
- Jerod M Rasmussen
- Development, Health, and Disease Research Program, University of California, Irvine. Irvine, CA, United States; Department of Pediatrics, University of California, Irvine. Irvine, CA, United States; Department of Biomedical Engineering, University of California, Irvine. Irvine, CA, United States
| | - Frithjof Kruggel
- Department of Biomedical Engineering, University of California, Irvine. Irvine, CA, United States
| | - John H Gilmore
- Departments of Psychiatry and Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Martin Styner
- Departments of Psychiatry and Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Sonja Entringer
- Development, Health, and Disease Research Program, University of California, Irvine. Irvine, CA, United States; Charité University Medicine Berlin, Institute for Medical Psychology,
Luisenstraße 57, 10117 Berlin, Germany
| | - Kirsten N Z Consing
- Departments of Psychiatry and Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Steven G Potkin
- Department of Psychiatry and Human Behavior, University of California, Irvine. Irvine, CA, United States
| | - Pathik D Wadhwa
- Development, Health, and Disease Research Program, University of California, Irvine. Irvine, CA, United States; Department of Pediatrics, University of California, Irvine. Irvine, CA, United States; Department of Psychiatry and Human Behavior, University of California, Irvine. Irvine, CA, United States
| | - Claudia Buss
- Development, Health, and Disease Research Program, University of California, Irvine. Irvine, CA, United States; Department of Pediatrics, University of California, Irvine. Irvine, CA, United States; Charité University Medicine Berlin, Institute for Medical Psychology,
Luisenstraße 57, 10117 Berlin, Germany.
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12
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Mironova YA, Lenk GM, Lin JP, Lee SJ, Twiss JL, Vaccari I, Bolino A, Havton LA, Min SH, Abrams CS, Shrager P, Meisler MH, Giger RJ. PI(3,5)P2 biosynthesis regulates oligodendrocyte differentiation by intrinsic and extrinsic mechanisms. eLife 2016; 5. [PMID: 27008179 PMCID: PMC4889328 DOI: 10.7554/elife.13023] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 03/23/2016] [Indexed: 12/18/2022] Open
Abstract
Proper development of the CNS axon-glia unit requires bi-directional communication between axons and oligodendrocytes (OLs). We show that the signaling lipid phosphatidylinositol-3,5-bisphosphate [PI(3,5)P2] is required in neurons and in OLs for normal CNS myelination. In mice, mutations of Fig4, Pikfyve or Vac14, encoding key components of the PI(3,5)P2 biosynthetic complex, each lead to impaired OL maturation, severe CNS hypomyelination and delayed propagation of compound action potentials. Primary OLs deficient in Fig4 accumulate large LAMP1+ and Rab7+ vesicular structures and exhibit reduced membrane sheet expansion. PI(3,5)P2 deficiency leads to accumulation of myelin-associated glycoprotein (MAG) in LAMP1+perinuclear vesicles that fail to migrate to the nascent myelin sheet. Live-cell imaging of OLs after genetic or pharmacological inhibition of PI(3,5)P2 synthesis revealed impaired trafficking of plasma membrane-derived MAG through the endolysosomal system in primary cells and brain tissue. Collectively, our studies identify PI(3,5)P2 as a key regulator of myelin membrane trafficking and myelinogenesis. DOI:http://dx.doi.org/10.7554/eLife.13023.001 Neurons communicate with each other through long cable-like extensions called axons. An insulating sheath called myelin (or white matter) surrounds each axon, and allows electrical impulses to travel more quickly. Cells in the brain called oligodendrocytes produce myelin. If the myelin sheath is not properly formed during development, or is damaged by injury or disease, the consequences can include paralysis, impaired thought, and loss of vision. Oligodendrocytes have complex shapes, and each can generate myelin for as many as 50 axons. Oligodendrocytes produce the building blocks of myelin inside their cell bodies, by following instructions encoded by genes within the nucleus. However, the signals that regulate the trafficking of these components to the myelin sheath are poorly understood. Mironova et al. set out to determine whether signaling molecules called phosphoinositides help oligodendrocytes to mature and move myelin building blocks from the cell bodies to remote contact points with axons. Genetic techniques were used to manipulate an enzyme complex in mice that controls the production and turnover of a phosphoinositide called PI(3,5)P2. Mironova et al. found that reducing the levels of PI(3,5)P2 in oligodendrocytes caused the trafficking of certain myelin building blocks to stall. Key myelin components instead accumulated inside bubble-like structures near the oligodendrocyte’s cell body. This showed that PI(3,5)P2 in oligodendrocytes is essential for generating myelin. Further experiments then revealed that reducing PI(3,5)P2 in the neurons themselves indirectly prevented the oligodendrocytes from maturing. This suggests that PI(3,5)P2 also takes part in communication between axons and oligodendrocytes during development of the myelin sheath. A key next step will be to identify the regulatory mechanisms that control the production of PI(3,5)P2 in oligodendrocytes and neurons. Future studies could also explore what PI(3,5)P2 acts upon inside the axons, and which signaling molecules support the maturation of oligodendrocytes. Finally, it remains unclear whether PI(3,5)P2signaling is also required for stabilizing mature myelin, and for repairing myelin after injury in the adult brain. Further work could therefore address these questions as well. DOI:http://dx.doi.org/10.7554/eLife.13023.002
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Affiliation(s)
- Yevgeniya A Mironova
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, United States.,Cellular and Molecular Biology Graduate Program, University of Michigan School of Medicine, Ann Arbor, United States
| | - Guy M Lenk
- Department of Human Genetics, University of Michigan School of Medicine, Ann Arbor, United States
| | - Jing-Ping Lin
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, United States
| | - Seung Joon Lee
- Department of Biological Sciences, University of South Carolina, Columbia, United States
| | - Jeffery L Twiss
- Department of Biological Sciences, University of South Carolina, Columbia, United States
| | - Ilaria Vaccari
- Human Inherited Neuropathies Unit, INSPE-Institute for Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
| | - Alessandra Bolino
- Human Inherited Neuropathies Unit, INSPE-Institute for Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
| | - Leif A Havton
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, United States
| | - Sang H Min
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, United States
| | - Charles S Abrams
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, United States
| | - Peter Shrager
- Department of Neurobiology and Anatomy, University of Rochester Medical Center, Rochester, United States
| | - Miriam H Meisler
- Department of Human Genetics, University of Michigan School of Medicine, Ann Arbor, United States.,Department of Neurology, University of Michigan School of Medicine, Ann Arbor, United States
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, United States.,Department of Neurology, University of Michigan School of Medicine, Ann Arbor, United States
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13
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Kraus A, Michalak M. Endoplasmic reticulum quality control and dysmyelination. Biomol Concepts 2015; 2:261-74. [PMID: 25962034 DOI: 10.1515/bmc.2011.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Dysmyelination contributes to several human diseases including multiple sclerosis, Charcot-Marie-Tooth, leukodystrophies, and schizophrenia and can result in serious neurological disability. Properly formed, compacted myelin sheaths are required for appropriate nerve conduction velocities and the health and survival of neurons. Many different molecular mechanisms contribute to dysmyelination and many of these mechanisms originate at the level of the endoplasmic reticulum. The endoplasmic reticulum is a critical organelle for myelin biosynthesis and maintenance as the site of myelin protein folding quality control, Ca2+ homeostasis, cholesterol biosynthesis, and modulation of cellular stress. This review paper highlights the role of the endoplasmic reticulum and its resident molecules as an upstream and dynamic contributor to myelin and myelin pathologies.
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14
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Czepiel M, Leicher L, Becker K, Boddeke E, Copray S. Overexpression of polysialylated neural cell adhesion molecule improves the migration capacity of induced pluripotent stem cell-derived oligodendrocyte precursors. Stem Cells Transl Med 2014; 3:1100-9. [PMID: 25069776 DOI: 10.5966/sctm.2014-0041] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Cell replacement therapy aiming at the compensation of lost oligodendrocytes and restoration of myelination in acquired or congenital demyelination disorders has gained considerable interest since the discovery of induced pluripotent stem cells (iPSCs). Patient-derived iPSCs provide an inexhaustible source for transplantable autologous oligodendrocyte precursors (OPCs). The first transplantation studies in animal models for demyelination with iPSC-derived OPCs demonstrated their survival and remyelinating capacity, but also revealed their limited migration capacity. In the present study, we induced overexpression of the polysialylating enzyme sialyltransferase X (STX) in iPSC-derived OPCs to stimulate the production of polysialic acid-neuronal cell adhesion molecules (PSA-NCAMs), known to promote and facilitate the migration of OPCs. The STX-overexpressing iPSC-derived OPCs showed a normal differentiation and maturation pattern and were able to downregulate PSA-NCAMs when they became myelin-forming oligodendrocytes. After implantation in the demyelinated corpus callosum of cuprizone-fed mice, STX-expressing iPSC-derived OPCs demonstrated a significant increase in migration along the axons. Our findings suggest that the reach and efficacy of iPSC-derived OPC transplantation can be improved by stimulating the OPC migration potential via specific gene modulation.
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Affiliation(s)
- Marcin Czepiel
- Department of Neuroscience, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
| | - Lasse Leicher
- Department of Neuroscience, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
| | - Katja Becker
- Department of Neuroscience, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
| | - Erik Boddeke
- Department of Neuroscience, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
| | - Sjef Copray
- Department of Neuroscience, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
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15
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Oligodendrocyte loss during the disease course in a canine model of the lysosomal storage disease fucosidosis. J Neuropathol Exp Neurol 2014; 73:536-47. [PMID: 24806306 DOI: 10.1097/nen.0000000000000075] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Hypomyelination is a poorly understood feature of many neurodegenerative lysosomal storage diseases, including fucosidosis in children and animals. To gain insight into hypomyelination in fucosidosis, we investigated lysosomal storage, oligodendrocyte death, and axonal and neuron loss in CNS tissues of fucosidosis-affected dogs aged 3 weeks to 42 months using immunohistochemistry, electron microscopy, and gene expression assays. Vacuole accumulation in fucosidosis oligodendrocytes commenced by 5 weeks of age; all oligodendrocytes were affected by 16 weeks. Despite progressive vacuolation, mature oligodendrocyte loss by apoptosis (caspase-6 positive) in the corpus callosum and cerebellar white matter stabilized by 16 weeks, with no further subsequent loss. Axonal neurofilament loss progressed only in late disease, suggesting that disturbed axon-oligodendrocyte interactions are unlikely to be the primary cause of hypomyelination. A 67% decline in the number of Purkinje cell layer oligodendrocytes coincided with a 67% increase in the number of caspase-6-positive Purkinje cells at 16 weeks, suggesting that early oligodendrocyte loss contributes to Purkinje cell apoptosis. Fucosidosis hypomyelination appeared to follow normal spatiotemporal patterns of myelination, with greater loss of oligodendrocytes and larger downregulation of CNP, MAL, and PLP1 genes at 16 weeks in the cerebellum versus the frontal cortex. These studies suggest that survival of oligodendrocytes in fucosidosis is limited during active myelination, although the mechanisms remain unknown.
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16
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Shimizu S, Koyama Y, Hattori T, Tachibana T, Yoshimi T, Emoto H, Matsumoto Y, Miyata S, Katayama T, Ito A, Tohyama M. DBZ, a CNS-specific DISC1 binding protein, positively regulates oligodendrocyte differentiation. Glia 2014; 62:709-24. [PMID: 24481677 DOI: 10.1002/glia.22636] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Revised: 12/21/2013] [Accepted: 01/13/2014] [Indexed: 12/19/2022]
Abstract
Recent studies have shown changes in myelin genes and alterations in white matter structure in a wide range of psychiatric disorders. Here we report that DBZ, a central nervous system (CNS)-specific member of the DISC1 interactome, positively regulates the oligodendrocyte (OL) differentiation in vivo and in vitro. In mouse corpus callosum (CC), DBZ mRNA is expressed in OL lineage cells and expression of DBZ protein peaked before MBP expression. In the CC of DBZ-KO mice, we observed delayed myelination during the early postnatal period. Although the myelination delay was mostly recovered by adulthood, OLs with immature structural features were more abundant in adult DBZ-KO mice than in control mice. DBZ was also transiently upregulated during rat OL differentiation in vitro before myelin marker expression. DBZ knockdown by RNA interference resulted in a decreased expression of myelin-related markers and a low number of cells with mature characteristics, but with no effect on the proliferation of oligodendrocyte precursor cells. We also show that the expression levels of transcription factors having a negative-regulatory role in OL differentiation were upregulated when endogenous DBZ was knocked down. These results strongly indicate that OL differentiation in rodents is regulated by DBZ.
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Affiliation(s)
- Shoko Shimizu
- Department of Molecular Neuropsychiatry, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan; Division of Molecular Brain Science, Research Institute of Traditional Asian Medicine, Kinki University, Osaka-Sayama, Osaka, Japan
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17
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Franklin RJM, Gallo V. The translational biology of remyelination: past, present, and future. Glia 2014; 62:1905-15. [PMID: 24446279 DOI: 10.1002/glia.22622] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 11/07/2013] [Accepted: 12/10/2013] [Indexed: 01/01/2023]
Abstract
Amongst neurological diseases, multiple sclerosis (MS) presents an attractive target for regenerative medicine. This is because the primary pathology, the loss of myelin-forming oligodendrocytes, can be followed by a spontaneous and efficient regenerative process called remyelination. While cell transplantation approaches have been explored as a means of replacing lost oligodendrocytes, more recently therapeutic approaches that target the endogenous regenerative process have been favored. This is in large part due to our increasing understanding of (1) the cell types within the adult brain that are able to generate new oligodendrocytes, (2) the mechanisms and pathways by which this achieved, and (3) an emerging awareness of the reasons why remyelination efficiency eventually fails. Here we review some of these advances and also highlight areas where questions remain to be answered in both the biology and translational potential of this important regenerative process.
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Affiliation(s)
- Robin J M Franklin
- Wellcome Trust-MRC Cambridge Stem Cell Institute and Department of Veterinary Medicine, University of Cambridge, Cambridge, CB3 0ES, United Kingdom
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18
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Schulz F, Lutz D, Rusche N, Bastús NG, Stieben M, Höltig M, Grüner F, Weller H, Schachner M, Vossmeyer T, Loers G. Gold nanoparticles functionalized with a fragment of the neural cell adhesion molecule L1 stimulate L1-mediated functions. NANOSCALE 2013; 5:10605-10617. [PMID: 24056775 DOI: 10.1039/c3nr02707d] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The neural cell adhesion molecule L1 is involved in nervous system development and promotes regeneration in animal models of acute and chronic injury of the adult nervous system. To translate these conducive functions into therapeutic approaches, a 22-mer peptide that encompasses a minimal and functional L1 sequence of the third fibronectin type III domain of murine L1 was identified and conjugated to gold nanoparticles (AuNPs) to obtain constructs that interact homophilically with the extracellular domain of L1 and trigger the cognate beneficial L1-mediated functions. Covalent conjugation was achieved by reacting mixtures of two cysteine-terminated forms of this L1 peptide and thiolated poly(ethylene) glycol (PEG) ligands (~2.1 kDa) with citrate stabilized AuNPs of two different sizes (~14 and 40 nm in diameter). By varying the ratio of the L1 peptide-PEG mixtures, an optimized layer composition was achieved that resulted in the expected homophilic interaction of the AuNPs. These AuNPs were stable as tested over a time period of 30 days in artificial cerebrospinal fluid and interacted with the extracellular domain of L1 on neurons and Schwann cells, as could be shown by using cells from wild-type and L1-deficient mice. In vitro, the L1-derivatized particles promoted neurite outgrowth and survival of neurons from the central and peripheral nervous system and stimulated Schwann cell process formation and proliferation. These observations raise the hope that, in combination with other therapeutic approaches, L1 peptide-functionalized AuNPs may become a useful tool to ameliorate the deficits resulting from acute and chronic injuries of the mammalian nervous system.
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Affiliation(s)
- Florian Schulz
- Institut für Physikalische Chemie, Universität Hamburg, Grindelallee 117, 20146 Hamburg, Germany.
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19
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Ravasi M, Scuteri A, Pasini S, Bossi M, Menendez VR, Maggioni D, Tredici G. Undifferentiated MSCs are able to myelinate DRG neuron processes through p75. Exp Cell Res 2013; 319:2989-99. [DOI: 10.1016/j.yexcr.2013.08.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 08/02/2013] [Accepted: 08/14/2013] [Indexed: 12/13/2022]
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20
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Promoting return of function in multiple sclerosis: An integrated approach. Mult Scler Relat Disord 2013; 2:S2211-0348(13)00044-8. [PMID: 24363985 DOI: 10.1016/j.msard.2013.04.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Multiple sclerosis is a disease characterized by inflammatory demyelination, axonal degeneration and progressive brain atrophy. Most of the currently available disease modifying agents proved to be very effective in managing the relapse rate, however progressive neuronal damage continues to occur and leads to progressive accumulation of irreversible disability. For this reason, any therapeutic strategy aimed at restoration of function must take into account not only immunomodulation, but also axonal protection and new myelin formation. We further highlight the importance of an holistic approach, which considers the variability of therapeutic responsiveness as the result of the interplay between genetic differences and the epigenome, which is in turn affected by gender, age and differences in life style including diet, exercise, smoking and social interaction.
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21
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Neurotransmitter-triggered transfer of exosomes mediates oligodendrocyte-neuron communication. PLoS Biol 2013; 11:e1001604. [PMID: 23874151 PMCID: PMC3706306 DOI: 10.1371/journal.pbio.1001604] [Citation(s) in RCA: 605] [Impact Index Per Article: 55.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 05/29/2013] [Indexed: 11/23/2022] Open
Abstract
Neuronal activity provokes myelinating oligodendrocytes to release exosomes by stimulation of ionotropic glutamate receptors, and that once released, these vesicles are internalized by neurons conveying neuroprotection. Reciprocal interactions between neurons and oligodendrocytes are not only crucial for myelination, but also for long-term survival of axons. Degeneration of axons occurs in several human myelin diseases, however the molecular mechanisms of axon-glia communication maintaining axon integrity are poorly understood. Here, we describe the signal-mediated transfer of exosomes from oligodendrocytes to neurons. These endosome-derived vesicles are secreted by oligodendrocytes and carry specific protein and RNA cargo. We show that activity-dependent release of the neurotransmitter glutamate triggers oligodendroglial exosome secretion mediated by Ca2+ entry through oligodendroglial NMDA and AMPA receptors. In turn, neurons internalize the released exosomes by endocytosis. Injection of oligodendroglia-derived exosomes into the mouse brain results in functional retrieval of exosome cargo in neurons. Supply of cultured neurons with oligodendroglial exosomes improves neuronal viability under conditions of cell stress. These findings indicate that oligodendroglial exosomes participate in a novel mode of bidirectional neuron-glia communication contributing to neuronal integrity. Brain function largely depends on the communication between electrically excitable neurons and surrounding glial cells. Myelinating oligodendrocytes are a type of brain cell that insulate major neuronal processes (axons) and help to sustainably maintain axonal health, which is poorly understood in molecular terms. Several cell types release microvesicles termed exosomes that include genetic information (primarily RNA) and can act as vehicles transferring specific cargo to target cells. Here, we demonstrate that exosomes secreted by oligodendrocytes in response to neuronal signals enter neurons to make their cargo functionally available to the neuronal metabolism. We revealed in cultured cells that exosome release from oligodendrocytes is triggered by the neurotransmitter glutamate through activation of ionotropic glutamate receptors. We also show that glial exosomes are internalized by neurons via an endocytic pathway. By modifying oligodendroglial exosomes with a reporter enzyme, we could demonstrate that the exosome cargo is recovered by target neurons in culture as well as in vivo after injection of exosomes into the mouse brain. Neurons challenged with stressful growth conditions were protected when treated with oligodendroglial exosomes. The study introduces a new concept of reciprocal cell communication in the nervous system and identifies the signal-mediated transfer of exosomes from oligodendrocytes to neurons contributing to the preservation of axonal health.
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22
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Popescu BFG, Lucchinetti CF. Pathology of demyelinating diseases. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2013; 7:185-217. [PMID: 22313379 DOI: 10.1146/annurev-pathol-011811-132443] [Citation(s) in RCA: 260] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
There has been significant progress in our understanding of the pathology and pathogenesis of central nervous system inflammatory demyelinating diseases. Neuropathological studies have provided fundamental new insights into the pathogenesis of these disorders and have led to major advances in our understanding of multiple sclerosis (MS) heterogeneity, the substrate of irreversible progressive disability in MS, the relationship between inflammation and neurodegeneration in MS, the neuroimaging correlates of MS lesions, and the pathogenesis of other central nervous system inflammatory disorders, including neuromyelitis optica, acute disseminated encephalomyelitis, and Balo's concentric sclerosis. Herein, we review the pathological features of these central nervous system inflammatory demyelinating disorders and discuss neuropathological studies that have yielded novel insights into potential mechanisms involved in the formation of the demyelinated lesion.
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Affiliation(s)
- Bogdan F Gh Popescu
- Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7K 0M7, Canada.
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23
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Grade S, Bernardino L, Malva JO. Oligodendrogenesis from neural stem cells: perspectives for remyelinating strategies. Int J Dev Neurosci 2013; 31:692-700. [PMID: 23340483 DOI: 10.1016/j.ijdevneu.2013.01.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Revised: 01/04/2013] [Accepted: 01/07/2013] [Indexed: 01/19/2023] Open
Abstract
Mobilization of remyelinating cells spontaneously occurs in the adult brain. These cellular resources are specially active after demyelinating episodes in early phases of multiple sclerosis (MS). Indeed, oligodendrocyte precursor cells (OPCs) actively proliferate, migrate to and repopulate the lesioned areas. Ultimately, efficient remyelination is accomplished when new oligodendrocytes reinvest nude neuronal axons, restoring the normal properties of impulse conduction. As the disease progresses this fundamental process fails. Multiple causes seem to contribute to such transient decline, including the failure of OPCs to differentiate and enwrap the vulnerable neuronal axons. Regenerative medicine for MS has been mainly centered on the recruitment of endogenous self-repair mechanisms, or on transplantation approaches. The latter commonly involves grafting of neural precursor cells (NPCs) or neural stem cells (NSCs), with myelinogenic potential, in the injured areas. Both strategies require further understanding of the biology of oligodendrocyte differentiation and remyelination. Indeed, the success of transplantation largely depends on the pre-commitment of transplanted NPCs or NSCs into oligodendroglial cell type, while the endogenous differentiation of OPCs needs to be boosted in chronic stages of the disease. Thus, much effort has been focused on finding molecular targets that drive oligodendrocytes commitment and development. The present review explores several aspects of remyelination that must be considered in the design of a cell-based therapy for MS, and explores more deeply the challenge of fostering oligodendrogenesis. In this regard, we discuss herein a tool developed in our research group useful to search novel oligodendrogenic factors and to study oligodendrocyte differentiation in a time- and cost-saving manner.
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Affiliation(s)
- Sofia Grade
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal.
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24
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McDonald JW, Sadowsky CL, Stampas A. The changing field of rehabilitation: optimizing spontaneous regeneration and functional recovery. HANDBOOK OF CLINICAL NEUROLOGY 2012; 109:317-336. [PMID: 23098722 DOI: 10.1016/b978-0-444-52137-8.00020-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
For neurorehabilitation of patients with spinal cord injury (SCI), the traditional emphasis on social adaptation is being expanded to include strategies that promote plasticity and regeneration in the central nervous system. Such strategies are needed to optimize recovery of neurological function. For example, the known dependence of most cellular processes on physical activity has led to the novel concept that activity is important in neural repair. This hypothesis has given rise to activity-based restoration therapies (ABRT), which aim to optimize neural activity in the damaged spinal cord, particularly below the injury level. Here, we review the basic science and clinical evidence supporting the lifelong use of ABRT for recovery from spinal cord injury. We define and describe ABRT, and discuss its components, its clinical applications, its relationship to medical management of spinal cord injury, and the potential influences of medications on recovery. We also discuss the health benefits of ABRT under physiological and pathological conditions. We stress that lifelong ABRT is required to optimize return of function and to allow patients to benefit from any "cures" that will be discovered.
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Affiliation(s)
- John W McDonald
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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25
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Huang JK, Franklin RJM. Current status of myelin replacement therapies in multiple sclerosis. PROGRESS IN BRAIN RESEARCH 2012. [PMID: 23186717 DOI: 10.1016/b978-0-444-59544-7.00011-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Multiple sclerosis is an autoimmune disease of the human central nervous system characterized by immune-mediated myelin and axonal damage, and chronic axonal loss attributable to the absence of myelin sheaths. There are two aspects to the treatment of MS-first, the prevention of damage by suppressing the maladaptive immune system, and second, the long-term preservation of axons by the promotion of remyelination, a regenerative process in which new axons are restored to demyelinated axons. Medicine has made significant progress in the first of these in recent years-there is an increasing number of ever more effective disease-modifying immunomodulatory interventions. However, there are currently no widely used regenerative therapies in MS. Conceptually, there are two approaches to remyelination therapy-transplantation of myelinogenic cells and promotion of endogenous remyelination mediated by myelinogenic cells present within the diseased tissue. In this chapter, in addition to describing why remyelination therapies are important, we review both these approaches, outlining their current status and future developments.
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Affiliation(s)
- Jeffrey K Huang
- Wellcome Trust and MRC, Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK.
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26
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Fressinaud C, Berges R, Eyer J. Axon cytoskeleton proteins specifically modulate oligodendrocyte growth and differentiation in vitro. Neurochem Int 2012; 60:78-90. [DOI: 10.1016/j.neuint.2011.10.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 09/26/2011] [Accepted: 10/26/2011] [Indexed: 12/19/2022]
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27
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Becker D, McDonald JW. Approaches to repairing the damaged spinal cord: overview. HANDBOOK OF CLINICAL NEUROLOGY 2012; 109:445-61. [PMID: 23098730 DOI: 10.1016/b978-0-444-52137-8.00028-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Affecting young people during the most productive period of their lives, spinal cord injury (SCI) is a devastating problem for modern society. In the past, treating SCI seemed frustrating and hopeless because of the tremendous morbidity and mortality, life-shattering impact, and limited therapeutic options associated with the condition. Today, however, an understanding of the underlying pathophysiological mechanisms, the development of neuroprotective interventions, and progress toward regenerative interventions are increasing hope for functional restoration. In this chapter, we provide an overview of various repair strategies for the injured spinal cord. Special attention will be paid to strategies that promote spontaneous regeneration, including functional electrical stimulation, cell replacement, neuroprotection, and remyelination. The concept that limited rebuilding can provide a disproportionate improvement in quality of life is emphasized throughout. New surgical procedures, pharmacological treatments, and functional neuromuscular stimulation methods have evolved over the last decades and can improve functional outcomes after spinal cord injury; however, limiting secondary injury remains the primary goal. Tissue replacement strategies, including the use of embryonic stem cells, become an important tool and can restore function in animal models. Controlled clinical trials are now required to confirm these observations. The ultimate goal is to harness the body's own potential to replace lost central nervous system cells by activation of endogenous progenitor cell repair mechanisms.
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Affiliation(s)
- Daniel Becker
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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28
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Krämer-Albers EM, White R. From axon-glial signalling to myelination: the integrating role of oligodendroglial Fyn kinase. Cell Mol Life Sci 2011; 68:2003-12. [PMID: 21207100 PMCID: PMC11114493 DOI: 10.1007/s00018-010-0616-z] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Revised: 12/15/2010] [Accepted: 12/16/2010] [Indexed: 01/06/2023]
Abstract
Central nervous system myelination requires recognition and signalling processes between neuronal axons and oligodendrocytes. Complex cellular rearrangements occur in myelination-competent oligodendrocytes requiring spatio-temporal control mechanisms. Although the molecular repertoire is becoming increasingly transparent, the signalling mechanisms governing myelination initiation are only poorly understood. The non-receptor tyrosine kinase Fyn has been implicated in axon-glial signal transduction and in several cellular processes required for oligodendrocyte maturation and myelination. Here, we review oligodendroglial Fyn signalling and discuss the role of Fyn in axon-glia interaction mediating myelination.
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Affiliation(s)
- Eva-Maria Krämer-Albers
- Molecular Cell Biology, Department of Biology, Johannes Gutenberg University of Mainz, Bentzelweg 3, 55128 Mainz, Germany
| | - Robin White
- Institute of Physiology and Pathophysiology, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, 55128 Mainz, Germany
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29
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Guseva D, Zerwas M, Xiao MF, Jakovcevski I, Irintchev A, Schachner M. Adhesion molecule L1 overexpressed under the control of the neuronal Thy-1 promoter improves myelination after peripheral nerve injury in adult mice. Exp Neurol 2011; 229:339-52. [PMID: 21376041 DOI: 10.1016/j.expneurol.2011.02.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 02/21/2011] [Accepted: 02/24/2011] [Indexed: 01/11/2023]
Abstract
L1 is an adhesion molecule favorably influencing the functional and anatomical recoveries after central nervous system (CNS) injuries. Its roles in peripheral nervous system (PNS) regeneration are less well understood. Studies using knockout mice have surprisingly revealed that L1 has a negative impact on functional nerve regeneration by inhibiting Schwann cell proliferation. To further elucidate the roles of L1 in PNS regeneration, here we used a novel transgenic mouse overexpressing L1 in neurons, but not in PNS or CNS glial cells, under the control of a neuron-specific Thy-1 promoter. Without nerve injury, the transgene expression, as compared to wild-type mice, had no effect on femoral nerve function, numbers of quadriceps motoneurons and myelinated axons in the femoral nerve but resulted in slightly reduced myelination in the sensory saphenous nerve and increased neurofilament density in myelinated axons of the quadriceps motor nerve branch. After femoral nerve injury, L1 overexpression had no impact on the time course and degree of functional recovery. Unaffected were also numbers of regenerated quadriceps motoneurons, precision of muscle reinnervation, axon numbers and internodal lengths in the regenerated nerves. Despite the lack of functional effects, myelination in the motor and sensory femoral nerve branches was significantly improved and loss of perisomatic inhibitory terminals on motoneurons was attenuated in the transgenic mice. Our results indicate that L1 is a regulator of myelination in the injured PNS and warrant studies aiming to improve function in demyelinating PNS and CNS disorders using exogenous L1.
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Affiliation(s)
- Daria Guseva
- Zentrum für Molekulare Neurobiologie, University Hospital Hamburg-Eppendorf, Martinistrasse 52, D-20246 Hamburg, Germany
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30
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Harsan LA, Paul D, Schnell S, Kreher BW, Hennig J, Staiger JF, von Elverfeldt D. In vivo diffusion tensor magnetic resonance imaging and fiber tracking of the mouse brain. NMR IN BIOMEDICINE 2010; 23:884-96. [PMID: 20213629 DOI: 10.1002/nbm.1496] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Until very recently, the study of neural architecture using fixed tissue has been a major scientific focus of neurologists and neuroanatomists. A non-invasive detailed insight into the brain's axonal connectivity in vivo has only become possible since the development of diffusion tensor magnetic resonance imaging (DT-MRI). This unique approach of analyzing axonal projections in the living brain was used in the present study to describe major white matter fiber tracts of the mouse brain and also to identify for the first time non-invasively the rich connectivity between the amygdala and different target regions. To overcome the difficulties associated with high spatially and temporally resolved DT-MRI measurements a 4-shot diffusion weighted spin echo (SE) echo planar imaging (EPI) protocol was adapted to mouse brain imaging at 9.4T. Diffusion tensor was calculated from data sets acquired by using 30 diffusion gradient directions while keeping the acquisition time at 91 min. Two fiber tracking algorithms were employed. A deterministic approach (fiber assignment by continuous tracking - FACT algorithm) allowed us to identify and generate the 3D representations of various neural pathways. A probabilistic approach was further used for the generation of probability maps of connectivity with which it was possible to investigate - in a statistical sense - all possible connecting pathways between selected seed points. We show here applications to determine the connection probability between regions belonging to the visual or limbic systems. This method does not require a priori knowledge about the projections' trajectories and is shown to be efficient even if the investigated pathway is long or three-dimensionally complex. Additionally, high resolution images of rotational invariant parameters of the diffusion tensor, such as fractional anisotropy, volume ratio or main eigenvalues allowed quantitative comparisons in-between regions of interest (ROIs) and showed significant differences between various white matter regions.
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Affiliation(s)
- Laura-Adela Harsan
- Department of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Germany.
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31
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Abstract
The myelin sheath wraps large axons in both the CNS and the PNS, and is a key determinant of efficient axonal function and health. Myelin is targeted in a series of diseases, notably multiple sclerosis (MS). In MS, demyelination is associated with progressive axonal damage, which determines the level of patient disability. The few treatments that are available for combating myelin damage in MS and related disorders, which largely comprise anti-inflammatory drugs, only show limited efficacy in subsets of patients. More-effective treatment of myelin disorders will probably be accomplished by early intervention with combinatorial therapies that target inflammation and other processes-for example, signaling pathways that promote remyelination. Indeed, evidence suggests that such pathways might be impaired in pathology and, hence, contribute to the failure of remyelination in such diseases. In this article, we review the molecular basis of signaling pathways that regulate myelination in the CNS and PNS, with a focus on signals that affect differentiation of myelinating glia. We also discuss factors such as extracellular molecules that act as modulators of these pathways. Finally, we consider the few preclinical and clinical trials of agents that augment this signaling.
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Becker D, Gary DS, Rosenzweig ES, Grill WM, McDonald JW. Functional electrical stimulation helps replenish progenitor cells in the injured spinal cord of adult rats. Exp Neurol 2010; 222:211-8. [PMID: 20059998 DOI: 10.1016/j.expneurol.2009.12.029] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 12/19/2009] [Accepted: 12/29/2009] [Indexed: 12/21/2022]
Abstract
Functional electrical stimulation (FES) can restore control and offset atrophy to muscles after neurological injury. However, FES has not been considered as a method for enhancing CNS regeneration. This paper demonstrates that FES dramatically enhanced progenitor cell birth in the spinal cord of rats with a chronic spinal cord injury (SCI). A complete SCI at thoracic level 8/9 was performed on 12 rats. Three weeks later, a FES device to stimulate hindlimb movement was implanted into these rats. Twelve identically-injured rats received inactive FES implants. An additional control group of uninjured rats were also examined. Ten days after FES implantation, dividing cells were marked with bromodeoxyuridine (BrdU). The "cell birth" subgroup (half the animals in each group) was sacrificed immediately after completion of BrdU administration, and the "cell survival" subgroup was sacrificed 7 days later. In the injured "cell birth" subgroup, FES induced an 82-86% increase in cell birth in the lumbar spinal cord. In the injured "cell survival" subgroup, the increased lumbar newborn cell counts persisted. FES doubled the proportion of the newly-born cells which expressed nestin and other markers suggestive of tripotential progenitors. In uninjured rats, FES had no effect on cell birth/survival. This report suggests that controlled electrical activation of the CNS may enhance spontaneous regeneration after neurological injuries.
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Affiliation(s)
- Daniel Becker
- International Center, for Spinal Cord Injury, Hugo Moser Research Institute, Department of Neurology, Johns Hopkins School of Medicine and Kennedy Krieger Institute, Baltimore, MD 21205, USA
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Bruce CC, Zhao C, Franklin RJM. Remyelination - An effective means of neuroprotection. Horm Behav 2010; 57:56-62. [PMID: 19538961 DOI: 10.1016/j.yhbeh.2009.06.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Revised: 06/04/2009] [Accepted: 06/09/2009] [Indexed: 10/20/2022]
Abstract
Remyelination following central nervous system (CNS) demyelination restores rapid saltatory conduction of action potentials and contributes to the maintenance of axonal integrity. This robust regenerative phenomenon stands in contrast to the limited repair capacity that is characteristic of CNS neuronal injury. However, despite its efficiency in experimental models and some clinical diseases, remyelination failure becomes an increasingly pronounced feature of the pathology of chronic multiple sclerosis (MS) lesions. Chronic demyelination predisposes axons to atrophy, an irreversible event that is a major pathological correlate of progressive functional decline. This has created a compelling case for developing therapies that promote remyelination: evidence from experimental animal models suggests that hormones may have a beneficial role to play in this regard.
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Arda H, Oner A, Gumus K, Karakucuk S, Mirza E. The results of electrophysiological tests in unilateral extensive peripapillary myelinated nerve fibers: report of three cases. Doc Ophthalmol 2009; 119:225-8. [PMID: 19809844 DOI: 10.1007/s10633-009-9199-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2009] [Accepted: 09/21/2009] [Indexed: 11/26/2022]
Abstract
The purpose of this study is to describe clinical and electrophysiological findings of three patients with unilateral extensive peripapillary myelinated nerve fibers. Three patients with unilateral extensive peripapillary myelinated nerve fibers were examined. A complete ophthalmologic examination including uncorrected and best spectacle corrected visual acuities (UCVA, BSCVA) on Snellen charts, dilated fundoscopy, fundus fluorescein angiography (FFA), optical coherence tomography (OCT), perimetry and electrophysiological tests was performed. ERG results of both eyes were normal in all cases. FFA showed hypofluorescence at the myelinated nerve fibers (MNF) area in the affected eyes. We found a visual field defect resembling arcuat scotom at perimetry of the affected eyes. In OCT, there was hyper-reflectivity in reply to MNF. In all cases, pattern ERG results of the affected eyes showed decreased amplitudes and increased latencies of P50 and N95 waves. P100 amplitudes of PVER and FVER were decreased, and latencies were increased in all affected eyes. Extensive peripapillary myelinated nerve fibers may cause changes in PERG and VER.
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Affiliation(s)
- Hatice Arda
- Department of Ophthalmology, Erciyes University Medical Faculty, 38039, Kayseri, Turkey
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Guseva D, Angelov DN, Irintchev A, Schachner M. Ablation of adhesion molecule L1 in mice favours Schwann cell proliferation and functional recovery after peripheral nerve injury. ACTA ACUST UNITED AC 2009; 132:2180-95. [PMID: 19541848 DOI: 10.1093/brain/awp160] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The adhesion molecule L1 is one of the few adhesion molecules known to be beneficial for repair processes in the adult central nervous system of vertebrates by promoting axonal growth and neuronal survival. In the peripheral nervous system, L1 is up-regulated by myelination-competent Schwann cells and regenerating axons after nerve damage but its functional role has remained unknown. Here we tested the hypothesis that L1 is, as in the central nervous system, beneficial for nerve regeneration in the peripheral nervous system by performing combined functional and histological analyses of adult L1-deficient mice (L1y/-) and wild-type (L1y/+) littermates. Contrary to our hypothesis, quantitative video-based motion analysis revealed better locomotor recovery in L1y/- than in L1y/+ mice at 4-12 weeks after transection and surgical repair of the femoral nerve. Motoneuron regeneration in L1y/- mice was also enhanced as indicated by attenuated post-traumatic loss of motoneurons, enhanced precision of motor reinnervation, larger cell bodies of regenerated motoneurons and diminished loss of inhibitory synaptic input to motoneurons. In search of mechanisms underlying the observed effects, we analysed peripheral nerves at short time-periods (3-14 days) after transection and found that Schwann cell proliferation is strongly augmented in L1y/- versus L1y/+ mice. L1-deficient Schwann cells showed increased proliferation than wild-type Schwann cells, both in vivo and in vitro. These findings suggest a novel role for L1 in nerve regeneration. We propose that L1 negatively regulates Schwann cell proliferation after nerve damage, which in turn restricts functional recovery by limiting the trophic support for regenerating motoneurons.
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Affiliation(s)
- Daria Guseva
- Zentrum für Molekulare Neurobiologie, Universität Hamburg, Hamburg, Germany
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Abstract
In making a selection of cellular tools and animal models for generating screening assays in the search for new drugs, one needs to take into consideration the practicality of their use in the drug discovery process. Conducting high-throughput primary screens using libraries of small molecules, close to 1 million members in size, requires the generation of large numbers of cells which are easily acquired, reliably enriched, and reproducibly responsive to standard positive controls. These cells need to be similar in form and function to their counterparts in human disease. In vitro assays that can be mechanized by using robots can therefore save time and costs. In selecting in vivo models, consideration must be given to the species and strain of animal chosen, the appropriateness of the model to human disease, the extent of animal husbandry required during the in-life pharmacological assessment, the technical aspects of generating the model and harvesting the tissues for analyses, the cost of research tools in terms of time and money (demyelinating and remyelinating agents, amount of compound to be generated), and the length of time required for drug testing in the model. A consideration of the translational aspects of the in vivo model compared to those used in the clinic is also important. These themes will be developed with examples for drug discovery in the field of CNS demyelination and repair, specifically as it pertains to multiple sclerosis.
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Oligodendrocyte differentiation and implantation: new insights for remyelinating cell therapy. Curr Opin Neurol 2008; 21:607-14. [PMID: 18769257 DOI: 10.1097/wco.0b013e32830f1e50] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
PURPOSE OF REVIEW Recent research on oligodendrocyte development has yielded new insights on the involvement of morphogens and differentiation factors in oligodendrogenesis. This knowledge has improved strategies to control neural stem cell-derived oligodendrocyte differentiation and functional maturation in vitro. In this review, we highlight the current knowledge on oligodendrocyte differentiation and discuss the novel possibilities of neural stem cell-derived oligodendrocytes for graft-based remyelination therapy, for example, for multiple sclerosis. RECENT FINDINGS Detailed insight into the cellular and molecular processes of embryonic and adult oligodendrogenesis has extended considerably in the past 2 years. Application of extrinsic factors and manipulation of intrinsic factors in neural stem cells have yielded convincing oligodendrocyte differentiation strategies. In addition, the recent groundbreaking developments regarding induced pluripotent stem cells generated from easily accessible somatic cells seem to offer an almost inexhaustible source for transplantable, autologous neural stem cells. Moreover, new approaches to optimize the implantation site for oligodendrocyte survival and functionality have improved the feasibility of stem cell-based oligodendrocyte replacement therapy. SUMMARY Loss of myelin in demyelinating diseases is only partly restored by endogenous oligodendrocyte precursor cells. Application of optimally functional, neural stem cell-derived oligodendrocyte precursors at the lesion site has become a realistic therapeutic approach to promote the remyelination process.
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Abstract
Oligodendrocytes and Schwann cells are highly specialized glial cells that wrap axons with a multilayered myelin membrane for rapid impulse conduction. Investigators have recently identified axonal signals that recruit myelin-forming Schwann cells from an alternate fate of simple axonal engulfment. This is the evolutionary oldest form of axon-glia interaction, and its function is unknown. Recent observations suggest that oligodendrocytes and Schwann cells not only myelinate axons but also maintain their long-term functional integrity. Mutations in the mouse reveal that axonal support by oligodendrocytes is independent of myelin assembly. The underlying mechanisms are still poorly understood; we do know that to maintain axonal integrity, mammalian myelin-forming cells require the expression of some glia-specific proteins, including CNP, PLP, and MAG, as well as intact peroxisomes, none of which is necessary for myelin assembly. Loss of glial support causes progressive axon degeneration and possibly local inflammation, both of which are likely to contribute to a variety of neuronal diseases in the central and peripheral nervous systems.
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Affiliation(s)
- Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, D-37075 Göttingen, Germany.
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Kulbatski I, Mothe AJ, Parr AM, Kim H, Kang CE, Bozkurt G, Tator CH. Glial precursor cell transplantation therapy for neurotrauma and multiple sclerosis. ACTA ACUST UNITED AC 2008; 43:123-76. [PMID: 18706353 DOI: 10.1016/j.proghi.2008.04.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2008] [Accepted: 04/07/2008] [Indexed: 12/18/2022]
Abstract
Traumatic injury to the brain or spinal cord and multiple sclerosis (MS) share a common pathophysiology with regard to axonal demyelination. Despite advances in central nervous system (CNS) repair in experimental animal models, adequate functional recovery has yet to be achieved in patients in response to any of the current strategies. Functional recovery is dependent, in large part, upon remyelination of spared or regenerating axons. The mammalian CNS maintains an endogenous reservoir of glial precursor cells (GPCs), capable of generating new oligodendrocytes and astrocytes. These GPCs are upregulated following traumatic or demyelinating lesions, followed by their differentiation into oligodendrocytes. However, this innate response does not adequately promote remyelination. As a result, researchers have been focusing their efforts on harvesting, culturing, characterizing, and transplanting GPCs into injured regions of the adult mammalian CNS in a variety of animal models of CNS trauma or demyelinating disease. The technical and logistic considerations for transplanting GPCs are extensive and crucial for optimizing and maintaining cell survival before and after transplantation, promoting myelination, and tracking the fate of transplanted cells. This is especially true in trials of GPC transplantation in combination with other strategies such as neutralization of inhibitors to axonal regeneration or remyelination. Overall, such studies improve our understanding and approach to developing clinically relevant therapies for axonal remyelination following traumatic brain injury (TBI) or spinal cord injury (SCI) and demyelinating diseases such as MS.
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Affiliation(s)
- Iris Kulbatski
- Krembil Neuroscience Centre, Toronto Western Research Institute, 399 Bathurst Street, McLaughlin Pavilion #12-423, Toronto, Ontario, Canada M5T-2S8.
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White R, Gonsior C, Krämer-Albers EM, Stöhr N, Hüttelmaier S, Trotter J. Activation of oligodendroglial Fyn kinase enhances translation of mRNAs transported in hnRNP A2-dependent RNA granules. ACTA ACUST UNITED AC 2008; 181:579-86. [PMID: 18490510 PMCID: PMC2386098 DOI: 10.1083/jcb.200706164] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Central nervous system myelination requires the synthesis of large amounts of myelin basic protein (MBP) at the axon–glia contact site. MBP messenger RNA (mRNA) is transported in RNA granules to oligodendroglial processes in a translationally silenced state. This process is regulated by the trans-acting factor heterogeneous nuclear ribonucleoprotein (hnRNP) A2 binding to the cis-acting A2 response element (A2RE). Release of this repression of MBP mRNA translation is thus essential for myelination. Mice deficient in the Src family tyrosine kinase Fyn are hypomyelinated and contain reduced levels of MBP. Here, we identify hnRNP A2 as a target of activated Fyn in oligodendrocytes. We show that active Fyn phosphorylates hnRNP A2 and stimulates translation of an MBP A2RE–containing reporter construct. Neuronal adhesion molecule L1 binding to oligodendrocytes results in Fyn activation, which leads to an increase in hnRNP A2 phosphorylation. These results suggest that Fyn kinase activation results in the localized translation of MBP mRNA at sites of axon–glia contact and myelin deposition.
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Affiliation(s)
- Robin White
- Molecular Cell Biology, Department of Biology, Johannes Gutenberg University of Mainz, 55128 Mainz, Germany
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41
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Vincze A, Mázló M, Seress L, Komoly S, Ábrahám H. A correlative light and electron microscopic study of postnatal myelination in the murine corpus callosum. Int J Dev Neurosci 2008; 26:575-84. [DOI: 10.1016/j.ijdevneu.2008.05.003] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2008] [Revised: 04/28/2008] [Accepted: 05/03/2008] [Indexed: 11/15/2022] Open
Affiliation(s)
- András Vincze
- Central Electron Microscopic Laboratory, Faculty of MedicineUniversity of PécsPécsHungary
| | - Mária Mázló
- Central Electron Microscopic Laboratory, Faculty of MedicineUniversity of PécsPécsHungary
| | - László Seress
- Central Electron Microscopic Laboratory, Faculty of MedicineUniversity of PécsPécsHungary
| | - Sámuel Komoly
- Department of Neurology, Faculty of MedicineUniversity of PécsPécsHungary
| | - Hajnalka Ábrahám
- Central Electron Microscopic Laboratory, Faculty of MedicineUniversity of PécsPécsHungary
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42
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Dubois-Dalcq M, Williams A, Stadelmann C, Stankoff B, Zalc B, Lubetzki C. From fish to man: understanding endogenous remyelination in central nervous system demyelinating diseases. Brain 2008; 131:1686-700. [PMID: 18474520 PMCID: PMC2516372 DOI: 10.1093/brain/awn076] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In the central nervous system (CNS) of man, evolutionary pressure has preserved some capability for remyelination while axonal regeneration is very limited. In contrast, two efficient programmes of regeneration exist in the adult fish CNS, neurite regrowth and remyelination. The rapidity of CNS remyelination is critical since it not only restores fast conduction of nerve impulses but also maintains axon integrity. If myelin repair fails, axons degenerate, leading to increased disability. In the human CNS demyelinating disease multiple sclerosis (MS), remyelination often takes place in the midst of inflammation. Here, we discuss recent studies that address the innate repair capabilities of the axon-glia unit from fish to man. We propose that expansion of this research field will help find ways to maintain or enhance spontaneous remyelination in man.
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Affiliation(s)
- Monique Dubois-Dalcq
- National Institute of Neurological Disorders and Stroke, Porter Neuroscience Research Center, Bethesda, MD 20892-3706, USA.
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Kippert A, Trajkovic K, Fitzner D, Opitz L, Simons M. Identification of Tmem10/Opalin as a novel marker for oligodendrocytes using gene expression profiling. BMC Neurosci 2008; 9:40. [PMID: 18439243 PMCID: PMC2396630 DOI: 10.1186/1471-2202-9-40] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2007] [Accepted: 04/25/2008] [Indexed: 01/06/2023] Open
Abstract
Background During the development of the central nervous system, oligodendrocytes generate large amounts of myelin, a multilayered insulating membrane that ensheathes axons, thereby allowing the fast conduction of the action potential and maintaining axonal integrity. Differentiation of oligodendrocytes to myelin-forming cells requires the downregulation of RhoA GTPase activity. Results To gain insights into the molecular mechanisms of oligodendrocyte differentiation, we performed microarray expression profiling of the oligodendroglial cell line, Oli-neu, treated with the Rho kinase (ROCK) inhibitor, Y-27632 or with conditioned neuronal medium. This resulted in the identification of the transmembrane protein 10 (Tmem10/Opalin), a novel type I transmembrane protein enriched in differentiating oligodendrocytes. In primary cultures, Tmem10 was abundantly expressed in O4-positive oligodendrocytes, but not in oligodendroglial precursor cells, astrocytes, microglia or neurons. In mature oligodendrocytes Tmem10 was enriched in the rims and processes of the cells and was only found to a lesser extent in the membrane sheets. Conclusion Together, our results demonstrate that Tmem10 is a novel marker for in vitro generated oligodendrocytes.
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Affiliation(s)
- Angelika Kippert
- Centre for Biochemistry and Molecular Cell Biology, University of Göttingen Humboldtallee 23, Göttingen, Germany.
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Taveggia C, Thaker P, Petrylak A, Caporaso GL, Toews A, Falls DL, Einheber S, Salzer JL. Type III neuregulin-1 promotes oligodendrocyte myelination. Glia 2008; 56:284-93. [PMID: 18080294 DOI: 10.1002/glia.20612] [Citation(s) in RCA: 152] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The axonal signals that regulate oligodendrocyte myelination during development of the central nervous system (CNS) have not been established. In this study, we have examined the regulation of oligodendrocyte myelination by the type III isoform of neuregulin-1 (NRG1), a neuronal signal essential for Schwann cell differentiation and myelination. In contrast to Schwann cells, primary oligodendrocytes differentiate normally when cocultured with dorsal root ganglia (DRG) neurons deficient in type III NRG1. However, they myelinate type III NRG1-deficient neurites poorly in comparison to wild type cultures. Type III NRG1 is not sufficient to drive oligodendrocyte myelination as sympathetic neurons are not myelinated even with lentiviral-mediated expression of NRG1. Mice haploinsufficient for type III NRG1 are hypomyelinated in the brain, as evidenced by reduced amounts of myelin proteins and lipids and thinner myelin sheaths. In contrast, the optic nerve and spinal cord of heterozygotes are myelinated normally. Together, these results implicate type III NRG1 as a significant determinant of the extent of myelination in the brain and demonstrate important regional differences in the control of CNS myelination. They also indicate that oligodendrocyte myelination, but not differentiation, is promoted by axonal NRG1, underscoring important differences in the control of myelination in the CNS and peripheral nervous system (PNS).
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Affiliation(s)
- Carla Taveggia
- Department of Cell Biology, New York University School of Medicine, New York, New York, USA
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45
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Tarabishy AB, Alexandrou TJ, Traboulsi EI. Syndrome of myelinated retinal nerve fibers, myopia, and amblyopia: a review. Surv Ophthalmol 2008; 52:588-96. [PMID: 18029268 DOI: 10.1016/j.survophthal.2007.08.016] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Myelinated retinal nerve fibers are developmental anomalies that are present in approximately 1% of all eyes. They may be associated with ipsilateral high myopia and amblyopia, and also may occur in association with various ocular and systemic abnormalities. Lesions may be congenital or acquired, static or dynamic, and can regress in the setting of several described conditions. The pathogenesis is thought to be due to the presence of ectopic oligodendrocyte-like cells in the retina as a result of a development or acquired insult. Visual acuity is typically poor to begin with, and the improvement of visual function in patients undergoing occlusion therapy has been, in general, limited. We discuss a series of 11 patients seen at the Cole Eye Institute with the condition of myelinated retinal nerve fibers, myopia, and amblyopia and describe the clinical characteristics. Three patients also had optic nerve dysplasia and a discussion of the literature related to this association was also performed.
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Affiliation(s)
- Ahmad B Tarabishy
- Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio, USA
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Pellissier F, Gerber A, Bauer C, Ballivet M, Ossipow V. The adhesion molecule Necl-3/SynCAM-2 localizes to myelinated axons, binds to oligodendrocytes and promotes cell adhesion. BMC Neurosci 2007; 8:90. [PMID: 17967169 PMCID: PMC2176061 DOI: 10.1186/1471-2202-8-90] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2007] [Accepted: 10/29/2007] [Indexed: 01/15/2023] Open
Abstract
Background Cell adhesion molecules are plasma membrane proteins specialized in cell-cell recognition and adhesion. Two related adhesion molecules, Necl-1 and Necl-2/SynCAM, were recently described and shown to fulfill important functions in the central nervous system. The purpose of the work was to investigate the distribution, and the properties of Necl-3/SynCAM-2, a previously uncharacterized member of the Necl family with which it shares a conserved modular organization and extensive sequence homology. Results We show that Necl-3/SynCAM-2 is a plasma membrane protein that accumulates in several tissues, including those of the central and peripheral nervous system. There, Necl-3/SynCAM-2 is expressed in ependymal cells and in myelinated axons, and sits at the interface between the axon shaft and the myelin sheath. Several independent assays demonstrate that Necl-3/SynCAM-2 functionally and selectively interacts with oligodendrocytes. We finally prove that Necl-3/SynCAM-2 is a bona fide adhesion molecule that engages in homo- and heterophilic interactions with the other Necl family members, leading to cell aggregation. Conclusion Collectively, our manuscripts and the works on Necl-1 and SynCAM/Necl-2 reveal a complex set of interactions engaged in by the Necl proteins in the nervous system. Our work also support the notion that the family of Necl proteins fulfils key adhesion and recognition functions in the nervous system, in particular between different cell types.
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Affiliation(s)
- François Pellissier
- Department of Biochemistry, University of Geneva, 30 Quai Ernest Ansermet, Sciences II, 1211 Geneva 4, Switzerland.
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47
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Melli G, Höke A. Canadian Association of Neurosciences review: regulation of myelination by trophic factors and neuron-glial signaling. Can J Neurol Sci 2007; 34:288-95. [PMID: 17803025 DOI: 10.1017/s0317167100006703] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Myelination in the nervous system is a tightly regulated process that is mediated by both soluble and non-soluble factors acting on axons and glial cells. This process is bi-directional and involves a variety of neurotrophic and gliotrophic factors acting in paracrine and autocrine manners. Neuron-derived trophic factors play an important role in the control of early proliferation and differentiation of myelinating glial cells. At later stages of development, same molecules may play a different role and act as inducers of myelination rather than cell survival signals for myelinating glial cells. In return, myelinating glial cells provide trophic support for axons and protect them from injury. Chronic demyelination leads to secondary axonal degeneration that is responsible for long-term disability in primary demyelinating diseases such as multiple sclerosis and inherited demyelinating peripheral neuropathies. A better understanding of the molecular mechanisms controlling myelination may yield novel therapeutic targets for demyelinating nervous system disorders.
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Affiliation(s)
- Giorgia Melli
- Neuromuscular Diseases Unit (GM), IRCSS Foundation Neurological Institute Carlo Besta, via Celoria. II11 20133 - Milan, Italy
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Roth TM, Ramamurthy P, Ebisu F, Lisak RP, Bealmear BM, Barald KF. A mouse embryonic stem cell model of Schwann cell differentiation for studies of the role of neurofibromatosis type 1 in Schwann cell development and tumor formation. Glia 2007; 55:1123-33. [PMID: 17597122 DOI: 10.1002/glia.20534] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The neurofibromatosis Type 1 (NF1) gene functions as a tumor suppressor gene. One known function of neurofibromin, the NF1 protein product, is to accelerate the slow intrinsic GTPase activity of Ras to increase the production of inactive rasGDP, with wide-ranging effects on p21ras pathways. Loss of neurofibromin in the autosomal dominant disorder NF1 is associated with tumors of the peripheral nervous system, particularly neurofibromas, benign lesions in which the major affected cell type is the Schwann cell (SC). NF1 is the most common cancer predisposition syndrome affecting the nervous system. We have developed an in vitro system for differentiating mouse embryonic stem cells (mESC) that are NF1 wild type (+/+), heterozygous (+/-), or null (-/-) into SC-like cells to study the role of NF1 in SC development and tumor formation. These mES-generated SC-like cells, regardless of their NF1 status, express SC markers correlated with their stage of maturation, including myelin proteins. They also support and preferentially direct neurite outgrowth from primary neurons. NF1 null and heterozygous SC-like cells proliferate at an accelerated rate compared to NF1 wild type; this growth advantage can be reverted to wild type levels using an inhibitor of MAP kinase kinase (Mek). The mESC of all NF1 types can also be differentiated into neuron-like cells. This novel model system provides an ideal paradigm for studies of the role of NF1 in cell growth and differentiation of the different cell types affected by NF1 in cells with differing levels of neurofibromin that are neither transformed nor malignant.
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Affiliation(s)
- Therese M Roth
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, USA
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49
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Baron-Van Evercooren A, Lachapelle F, Nait-Oumesmar B, Pham-Dinh D. [Promoting myelin repair in disorders such as multiple sclerosis and some types of leukodystrophy: current studies]. Rev Neurol (Paris) 2007; 163:523-31. [PMID: 17571021 DOI: 10.1016/s0035-3787(07)90459-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Several ways of promoting myelin repair in myelin disorders such as multiple sclerosis and certain types of leukodystrophies are currently being investigated. Numerous studies suggest that it is possible to repair the central nervous system (CNS) by cell transplantation or by enhancing endogenous remyelination. Investigations in animal models indicate that cell therapy results in robust anatomical and functional recovery of acute myelin lesions. These models are also used to explore and validate the role of candidate molecules to stimulate endogenous remyelination by activating the myelin competent population or providing neuroprotection. However, in view of the heterogeneity of the lesion environment in MS, it seems more likely that cell therapy alone will not be able to contribute efficiently to the repair of the lesion. Further developments should indicate whether combining multiple approaches will be more powerful to achieve global myelin repair in the CNS than applying these strategies alone.
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Witte AV, Brummelte S, Teuchert-Noodt G. Developmental pattern changes of prefrontal efferents in the juvenile gerbil (Meriones unguiculatus). J Neural Transm (Vienna) 2007; 114:1377-93. [PMID: 17557126 DOI: 10.1007/s00702-007-0761-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2007] [Accepted: 05/02/2007] [Indexed: 10/23/2022]
Abstract
Previous findings of our group showed that early traumatisation leads to a dysfunctional organisation of prefrontocortical efferents in adulthood. To identify vulnerable time windows during maturation, we labelled either layer III- or layer V/VI-pyramidal cells with biocytin in the prefrontal cortex of gerbils (Meriones unguiculatus) from the age of postnatal day (PD) 15 up to adulthood (PD 90). The density of passing fibres and axonal terminals in distinct cortical columns in specific prefrontal projection areas was assessed by digital image analysis. Following layer III injections, fibre densities reached adult values between adolescence (PD 60) and adulthood (PD 90). However, layer V/VI-fibre densities decreased after eye-opening (PD 15), followed by an increase to adult values after weaning (PD 30). These findings are the first to describe dynamic structural changes even beyond adolescence of functionally diverse prefrontal output systems. External interventions might exert adverse influences on the establishment of integrated prefrontal networks especially during the early phase of re-arranging.
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Affiliation(s)
- A V Witte
- Department of Neuroanatomy, Faculty of Biology, University of Bielefeld, Bielefeld, Germany.
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