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Thümmler K, Wrzos C, Franz J, McElroy D, Cole JJ, Hayden L, Arseni D, Schwarz F, Junker A, Edgar JM, Kügler S, Neef A, Wolf F, Stadelmann C, Linington C. Fibroblast growth factor 9 (FGF9)-mediated neurodegeneration: Implications for progressive multiple sclerosis? Neuropathol Appl Neurobiol 2023; 49:e12935. [PMID: 37705188 DOI: 10.1111/nan.12935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 08/22/2023] [Accepted: 09/10/2023] [Indexed: 09/15/2023]
Abstract
AIMS Fibroblast growth factor (FGF) signalling is dysregulated in multiple sclerosis (MS) and other neurological and psychiatric conditions, but there is little or no consensus as to how individual FGF family members contribute to disease pathogenesis. Lesion development in MS is associated with increased expression of FGF1, FGF2 and FGF9, all of which modulate remyelination in a variety of experimental settings. However, FGF9 is also selectively upregulated in major depressive disorder (MDD), prompting us to speculate it may also have a direct effect on neuronal function and survival. METHODS Transcriptional profiling of myelinating cultures treated with FGF1, FGF2 or FGF9 was performed, and the effects of FGF9 on cortical neurons investigated using a combination of transcriptional, electrophysiological and immunofluorescence microscopic techniques. The in vivo effects of FGF9 were explored by stereotactic injection of adeno-associated viral (AAV) vectors encoding either FGF9 or EGFP into the rat motor cortex. RESULTS Transcriptional profiling of myelinating cultures after FGF9 treatment revealed a distinct neuronal response with a pronounced downregulation of gene networks associated with axonal transport and synaptic function. In cortical neuronal cultures, FGF9 also rapidly downregulated expression of genes associated with synaptic function. This was associated with a complete block in the development of photo-inducible spiking activity, as demonstrated using multi-electrode recordings of channel rhodopsin-transfected rat cortical neurons in vitro and, ultimately, neuronal cell death. Overexpression of FGF9 in vivo resulted in rapid loss of neurons and subsequent development of chronic grey matter lesions with neuroaxonal reduction and ensuing myelin loss. CONCLUSIONS These observations identify overexpression of FGF9 as a mechanism by which neuroaxonal pathology could develop independently of immune-mediated demyelination in MS. We suggest targeting neuronal FGF9-dependent pathways may provide a novel strategy to slow if not halt neuroaxonal atrophy and loss in MS, MDD and potentially other neurodegenerative diseases.
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Affiliation(s)
- Katja Thümmler
- School of Infection and Immunity, University of Glasgow, Glasgow, UK
| | - Claudia Wrzos
- Institute for Neuropathology, University Medical Center Göttingen, Göttingen, Germany
| | - Jonas Franz
- Institute for Neuropathology, University Medical Center Göttingen, Göttingen, Germany
- Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany
- Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Göttingen Campus Institute for Dynamics of Biological Networks, University of Göttingen, Göttingen, Germany
| | - Daniel McElroy
- School of Infection and Immunity, University of Glasgow, Glasgow, UK
| | - John J Cole
- School of Infection and Immunity, University of Glasgow, Glasgow, UK
| | - Lorna Hayden
- School of Infection and Immunity, University of Glasgow, Glasgow, UK
| | - Diana Arseni
- School of Infection and Immunity, University of Glasgow, Glasgow, UK
| | - Friedrich Schwarz
- Institute for Neuropathology, University Medical Center Göttingen, Göttingen, Germany
| | - Andreas Junker
- Institute for Neuropathology, University Medical Center Göttingen, Göttingen, Germany
- Department of Neuropathology, University Hospital Essen, Essen, Germany
| | - Julia M Edgar
- School of Infection and Immunity, University of Glasgow, Glasgow, UK
| | - Sebastian Kügler
- Institute for Neurology, University Medical Center Göttingen, Göttingen, Germany
- Center Nanoscale Microscopy and Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Andreas Neef
- Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany
- Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Göttingen Campus Institute for Dynamics of Biological Networks, University of Göttingen, Göttingen, Germany
- Center for Biostructural Imaging of Neurodegeneration, Göttingen, Germany
| | - Fred Wolf
- Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany
- Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Göttingen Campus Institute for Dynamics of Biological Networks, University of Göttingen, Göttingen, Germany
- Center for Biostructural Imaging of Neurodegeneration, Göttingen, Germany
- Cluster of Excellence Multiscale Bioimaging: From Molecular Machines to Network of Excitable Cells (MBExC), University of Goettingen, Göttingen, Germany
| | - Christine Stadelmann
- Institute for Neuropathology, University Medical Center Göttingen, Göttingen, Germany
- Cluster of Excellence Multiscale Bioimaging: From Molecular Machines to Network of Excitable Cells (MBExC), University of Goettingen, Göttingen, Germany
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2
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Schäffner E, Bosch-Queralt M, Edgar JM, Lehning M, Strauß J, Fleischer N, Kungl T, Wieghofer P, Berghoff SA, Reinert T, Krueger M, Morawski M, Möbius W, Barrantes-Freer A, Stieler J, Sun T, Saher G, Schwab MH, Wrede C, Frosch M, Prinz M, Reich DS, Flügel A, Stadelmann C, Fledrich R, Nave KA, Stassart RM. Myelin insulation as a risk factor for axonal degeneration in autoimmune demyelinating disease. Nat Neurosci 2023; 26:1218-1228. [PMID: 37386131 PMCID: PMC10322724 DOI: 10.1038/s41593-023-01366-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 05/17/2023] [Indexed: 07/01/2023]
Abstract
Axonal degeneration determines the clinical outcome of multiple sclerosis and is thought to result from exposure of denuded axons to immune-mediated damage. Therefore, myelin is widely considered to be a protective structure for axons in multiple sclerosis. Myelinated axons also depend on oligodendrocytes, which provide metabolic and structural support to the axonal compartment. Given that axonal pathology in multiple sclerosis is already visible at early disease stages, before overt demyelination, we reasoned that autoimmune inflammation may disrupt oligodendroglial support mechanisms and hence primarily affect axons insulated by myelin. Here, we studied axonal pathology as a function of myelination in human multiple sclerosis and mouse models of autoimmune encephalomyelitis with genetically altered myelination. We demonstrate that myelin ensheathment itself becomes detrimental for axonal survival and increases the risk of axons degenerating in an autoimmune environment. This challenges the view of myelin as a solely protective structure and suggests that axonal dependence on oligodendroglial support can become fatal when myelin is under inflammatory attack.
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Affiliation(s)
- Erik Schäffner
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Paul Flechsig Institute of Neuropathology, University Clinic Leipzig, Leipzig, Germany
| | - Mar Bosch-Queralt
- Paul Flechsig Institute of Neuropathology, University Clinic Leipzig, Leipzig, Germany
| | - Julia M Edgar
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Maria Lehning
- Paul Flechsig Institute of Neuropathology, University Clinic Leipzig, Leipzig, Germany
| | - Judith Strauß
- Institute of Neuroimmunology and Multiple Sclerosis Research, University Medical Center Göttingen, Göttingen, Germany
| | - Niko Fleischer
- Paul Flechsig Institute of Neuropathology, University Clinic Leipzig, Leipzig, Germany
| | - Theresa Kungl
- Institute of Anatomy, Leipzig University, Leipzig, Germany
| | - Peter Wieghofer
- Institute of Anatomy, Leipzig University, Leipzig, Germany
- Cellular Neuroanatomy, Institute of Theoretical Medicine, Medical Faculty, University of Augsburg, Augsburg, Germany
| | - Stefan A Berghoff
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Tilo Reinert
- Paul Flechsig Institute of Neuropathology, University Clinic Leipzig, Leipzig, Germany
- Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Martin Krueger
- Institute of Anatomy, Leipzig University, Leipzig, Germany
| | - Markus Morawski
- Paul Flechsig Institute of Brain Research, Leipzig University, Leipzig, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | | | - Jens Stieler
- Paul Flechsig Institute of Brain Research, Leipzig University, Leipzig, Germany
| | - Ting Sun
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Gesine Saher
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Markus H Schwab
- Paul Flechsig Institute of Neuropathology, University Clinic Leipzig, Leipzig, Germany
| | - Christoph Wrede
- Institute of Functional and Applied Anatomy, Research Core Unit Electron Microscopy, Hannover Medical School, Hannover, Germany
| | - Maximilian Frosch
- Institute of Neuropathology, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Marco Prinz
- Institute of Neuropathology, Medical Faculty, University of Freiburg, Freiburg, Germany
- Centre for NeuroModulation (NeuroModBasics), University of Freiburg, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Daniel S Reich
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Alexander Flügel
- Institute of Neuroimmunology and Multiple Sclerosis Research, University Medical Center Göttingen, Göttingen, Germany
| | - Christine Stadelmann
- Institute of Neuropathology, University Medical Center Göttingen, Göttingen, Germany
| | - Robert Fledrich
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
- Institute of Anatomy, Leipzig University, Leipzig, Germany.
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
| | - Ruth M Stassart
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
- Paul Flechsig Institute of Neuropathology, University Clinic Leipzig, Leipzig, Germany.
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Gamble A, Suessmilch M, Bonestroo A, Merits A, Graham GJ, Cavanagh J, Edgar JM, Pingen M. Establishing Mixed Neuronal and Glial Cell Cultures from Embryonic Mouse Brains to Study Infection and Innate Immunity. J Vis Exp 2023. [PMID: 37458443 DOI: 10.3791/65331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023] Open
Abstract
Models of the central nervous system (CNS) must recapitulate the complex network of interconnected cells found in vivo. The CNS consists primarily of neurons, astrocytes, oligodendrocytes, and microglia. Due to increasing efforts to replace and reduce animal use, a variety of in vitro cell culture systems have been developed to explore innate cell properties, which allow the development of therapeutics for CNS infections and pathologies. Whilst certain research questions can be addressed by human-based cell culture systems, such as (induced) pluripotent stem cells, working with human cells has its own limitations with regard to availability, costs, and ethics. Here, we describe a unique protocol for isolating and culturing cells from embryonic mouse brains. The resulting mixed neural cell cultures mimic several cell populations and interactions found in the brain in vivo. Compared to current equivalent methods, this protocol more closely mimics the characteristics of the brain and also garners more cells, thus allowing for more experimental conditions to be investigated from one pregnant mouse. Further, the protocol is relatively easy and highly reproducible. These cultures have been optimized for use at various scales, including 96-well based high throughput screens, 24-well microscopy analysis, and 6-well cultures for flow cytometry and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis. This culture method is a powerful tool to investigate infection and immunity within the context of some of the complexity of the CNS with the convenience of in vitro methods.
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Affiliation(s)
| | | | | | - Andres Merits
- Faculty of Science and Technology, Institute of Technology, University of Tartu
| | | | | | - Julia M Edgar
- School of Infection and Immunity, University of Glasgow
| | - Marieke Pingen
- School of Infection and Immunity, University of Glasgow;
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4
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Steyer AM, Buscham TJ, Lorenz C, Hümmert S, Eichel‐Vogel MA, Schadt LC, Edgar JM, Köster S, Möbius W, Nave K, Werner HB. Cover Image, Volume 71, Issue 3. Glia 2023. [DOI: 10.1002/glia.24198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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5
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Steyer AM, Buscham TJ, Lorenz C, Hümmert S, Eichel-Vogel MA, Schadt LC, Edgar JM, Köster S, Möbius W, Nave KA, Werner HB. Focused ion beam-scanning electron microscopy links pathological myelin outfoldings to axonal changes in mice lacking Plp1 or Mag. Glia 2023; 71:509-523. [PMID: 36354016 DOI: 10.1002/glia.24290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 10/10/2022] [Accepted: 10/17/2022] [Indexed: 11/11/2022]
Abstract
Healthy myelin sheaths consist of multiple compacted membrane layers closely encasing the underlying axon. The ultrastructure of CNS myelin requires specialized structural myelin proteins, including the transmembrane-tetraspan proteolipid protein (PLP) and the Ig-CAM myelin-associated glycoprotein (MAG). To better understand their functional relevance, we asked to what extent the axon/myelin-units display similar morphological changes if PLP or MAG are lacking. We thus used focused ion beam-scanning electron microscopy (FIB-SEM) to re-investigate axon/myelin-units side-by-side in Plp- and Mag-null mutant mice. By three-dimensional reconstruction and morphometric analyses, pathological myelin outfoldings extend up to 10 μm longitudinally along myelinated axons in both models. More than half of all assessed outfoldings emerge from internodal myelin. Unexpectedly, three-dimensional reconstructions demonstrated that both models displayed complex axonal pathology underneath the myelin outfoldings, including axonal sprouting. Axonal anastomosing was additionally observed in Plp-null mutant mice. Importantly, normal-appearing axon/myelin-units displayed significantly increased axonal diameters in both models according to quantitative assessment of electron micrographs. These results imply that healthy CNS myelin sheaths facilitate normal axonal diameters and shape, a function that is impaired when structural myelin proteins PLP or MAG are lacking.
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Affiliation(s)
- Anna M Steyer
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Electron Microscopy-City Campus, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Tobias J Buscham
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Charlotta Lorenz
- Institute for X-Ray Physics, University of Göttingen, Göttingen, Germany
| | - Sophie Hümmert
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Maria A Eichel-Vogel
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Leonie C Schadt
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Julia M Edgar
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Sarah Köster
- Institute for X-Ray Physics, University of Göttingen, Göttingen, Germany.,Cluster of Excellence 'Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells' (MBExC), University of Göttingen, Göttingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Electron Microscopy-City Campus, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Cluster of Excellence 'Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells' (MBExC), University of Göttingen, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
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6
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de Almeida MMA, Watson AES, Bibi S, Dittmann NL, Goodkey K, Sharafodinzadeh P, Galleguillos D, Nakhaei-Nejad M, Kosaraju J, Steinberg N, Wang BS, Footz T, Giuliani F, Wang J, Sipione S, Edgar JM, Voronova A. Fractalkine enhances oligodendrocyte regeneration and remyelination in a demyelination mouse model. Stem Cell Reports 2023; 18:519-533. [PMID: 36608690 PMCID: PMC9968989 DOI: 10.1016/j.stemcr.2022.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 12/06/2022] [Accepted: 12/07/2022] [Indexed: 01/07/2023] Open
Abstract
Demyelinating disorders of the central nervous system (CNS) occur when myelin and oligodendrocytes are damaged or lost. Remyelination and regeneration of oligodendrocytes can be achieved from endogenous oligodendrocyte precursor cells (OPCs) that reside in the adult CNS tissue. Using a cuprizone mouse model of demyelination, we show that infusion of fractalkine (CX3CL1) into the demyelinated murine brain increases de novo oligodendrocyte formation and enhances remyelination in the corpus callosum and cortical gray matter. This is achieved by increased OPC proliferation in the cortical gray matter as well as OPC differentiation and attenuation of microglia/macrophage activation both in corpus callosum and cortical gray matter. Finally, we show that activated OPCs and microglia/macrophages express fractalkine receptor CX3CR1 in vivo, and that in OPC-microglia co-cultures fractalkine increases in vitro oligodendrocyte differentiation by modulating both OPC and microglia biology. Our results demonstrate a novel pro-regenerative role of fractalkine in a demyelinating mouse model.
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Affiliation(s)
- Monique M A de Almeida
- Department of Medical Genetics, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada; Neuroscience and Mental Health Institute, Faculty of Medicine & Dentistry, Edmonton, AB T6G 2E1, Canada
| | - Adrianne E S Watson
- Department of Medical Genetics, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada; Women and Children's Health Research Institute, University of Alberta, 5-083 Edmonton Clinic Health Academy, 11405 87 Avenue NW, Edmonton, AB T6G 1C9, Canada
| | - Sana Bibi
- Department of Medical Genetics, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Nicole L Dittmann
- Department of Medical Genetics, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada; Neuroscience and Mental Health Institute, Faculty of Medicine & Dentistry, Edmonton, AB T6G 2E1, Canada
| | - Kara Goodkey
- Department of Medical Genetics, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada; Women and Children's Health Research Institute, University of Alberta, 5-083 Edmonton Clinic Health Academy, 11405 87 Avenue NW, Edmonton, AB T6G 1C9, Canada
| | - Pedram Sharafodinzadeh
- Department of Medical Genetics, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Danny Galleguillos
- Neuroscience and Mental Health Institute, Faculty of Medicine & Dentistry, Edmonton, AB T6G 2E1, Canada; Department of Pharmacology, Faculty of Medicine & Dentistry, Edmonton, AB T6G 2H7, Canada
| | - Maryam Nakhaei-Nejad
- Department of Medicine, Faculty of Medicine & Dentistry, Edmonton, AB T6G 2H7, Canada
| | - Jayasankar Kosaraju
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada
| | - Noam Steinberg
- Neuroscience and Mental Health Institute, Faculty of Medicine & Dentistry, Edmonton, AB T6G 2E1, Canada; Department of Pharmacology, Faculty of Medicine & Dentistry, Edmonton, AB T6G 2H7, Canada
| | - Beatrix S Wang
- Department of Medical Genetics, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada; Women and Children's Health Research Institute, University of Alberta, 5-083 Edmonton Clinic Health Academy, 11405 87 Avenue NW, Edmonton, AB T6G 1C9, Canada
| | - Tim Footz
- Department of Medical Genetics, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Fabrizio Giuliani
- Department of Medicine, Faculty of Medicine & Dentistry, Edmonton, AB T6G 2H7, Canada; Multiple Sclerosis Centre and Department of Cell Biology, Faculty of Medicine & Dentistry, Edmonton, AB T6G 2H7, Canada
| | - Jing Wang
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada; Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa Brain and Mind Research Institute, Ottawa, ON K1H 8M5, Canada
| | - Simonetta Sipione
- Neuroscience and Mental Health Institute, Faculty of Medicine & Dentistry, Edmonton, AB T6G 2E1, Canada; Department of Pharmacology, Faculty of Medicine & Dentistry, Edmonton, AB T6G 2H7, Canada
| | - Julia M Edgar
- School of Infection and Immunity, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK
| | - Anastassia Voronova
- Department of Medical Genetics, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada; Women and Children's Health Research Institute, University of Alberta, 5-083 Edmonton Clinic Health Academy, 11405 87 Avenue NW, Edmonton, AB T6G 1C9, Canada; Neuroscience and Mental Health Institute, Faculty of Medicine & Dentistry, Edmonton, AB T6G 2E1, Canada; Department of Cell Biology, Faculty of Medicine & Dentistry, Edmonton, AB T6G 2H7, Canada; Multiple Sclerosis Centre and Department of Cell Biology, Faculty of Medicine & Dentistry, Edmonton, AB T6G 2H7, Canada.
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7
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Baldacchino K, Peveler WJ, Lemgruber L, Smith RS, Scharler C, Hayden L, Komarek L, Lindsay SL, Barnett SC, Edgar JM, Linington C, Thümmler K. Myelinated axons are the primary target of hemin-mediated oxidative damage in a model of the central nervous system. Exp Neurol 2022; 354:114113. [PMID: 35569511 DOI: 10.1016/j.expneurol.2022.114113] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 04/29/2022] [Accepted: 05/08/2022] [Indexed: 12/01/2022]
Abstract
Iron released from oligodendrocytes during demyelination or derived from haemoglobin breakdown products is believed to amplify oxidative tissue injury in multiple sclerosis (MS). However, the pathophysiological significance of iron-containing haemoglobin breakdown products themselves is rarely considered in the context of MS and their cellular specificity and mode of action remain unclear. Using myelinating cell cultures, we now report the cytotoxic potential of hemin (ferriprotoporphyrin IX chloride), a major degradation product of haemoglobin, is 25-fold greater than equimolar concentrations of free iron in myelinating cultures; a model that reproduces the complex multicellular environment of the CNS. At low micro molar concentrations (3.3 - 10 μM) we observed hemin preferentially binds to myelin and axons to initiate a complex detrimental response that results in targeted demyelination and axonal loss but spares neuronal cell bodies, astrocytes and the majority of oligodendroglia. Demyelination and axonal loss in this context are executed by a combination of mechanisms that include iron-dependent peroxidation by reactive oxygen species (ROS) and ferroptosis. These effects are microglial-independent, do not require any initiating inflammatory insult and represent a direct effect that compromises the structural integrity of myelinated axons in the CNS. Our data identify hemin-mediated demyelination and axonal loss as a novel mechanism by which intracerebral degradation of haemoglobin may contribute to lesion development in MS.
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Affiliation(s)
- Karl Baldacchino
- Institute of Infection, Immunity and Inflammation, University of Glasgow, G12 8TA Glasgow, United Kingdom
| | - William J Peveler
- WestCHEM, School of Chemistry, University of Glasgow, Joseph Black Building, G12 8QQ Glasgow, UK
| | - Leandro Lemgruber
- Glasgow Imaging Facility, Institute of Infection, Immunity and Inflammation, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK
| | - Rebecca Sherrard Smith
- Institute of Infection, Immunity and Inflammation, University of Glasgow, G12 8TA Glasgow, United Kingdom
| | - Cornelia Scharler
- Institute of Experimental and Clinical Cell Therapy, Paracelsus Medical University, Salzburg, Austria
| | - Lorna Hayden
- Institute of Infection, Immunity and Inflammation, University of Glasgow, G12 8TA Glasgow, United Kingdom
| | - Lina Komarek
- Institute of Infection, Immunity and Inflammation, University of Glasgow, G12 8TA Glasgow, United Kingdom
| | - Susan L Lindsay
- Institute of Infection, Immunity and Inflammation, University of Glasgow, G12 8TA Glasgow, United Kingdom
| | - Susan C Barnett
- Institute of Infection, Immunity and Inflammation, University of Glasgow, G12 8TA Glasgow, United Kingdom
| | - Julia M Edgar
- Institute of Infection, Immunity and Inflammation, University of Glasgow, G12 8TA Glasgow, United Kingdom
| | - Christopher Linington
- Institute of Infection, Immunity and Inflammation, University of Glasgow, G12 8TA Glasgow, United Kingdom
| | - Katja Thümmler
- Institute of Infection, Immunity and Inflammation, University of Glasgow, G12 8TA Glasgow, United Kingdom.
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8
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Crawford CL, Antoniou C, Komarek L, Schultz V, Donald CL, Montague P, Barnett SC, Linington C, Willison HJ, Kohl A, Coleman MP, Edgar JM. SARM1 Depletion Slows Axon Degeneration in a CNS Model of Neurotropic Viral Infection. Front Mol Neurosci 2022; 15:860410. [PMID: 35493328 PMCID: PMC9043327 DOI: 10.3389/fnmol.2022.860410] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 02/18/2022] [Indexed: 01/30/2023] Open
Abstract
Zika virus (ZIKV) is a neurotropic flavivirus recently linked to congenital ZIKV syndrome in children and encephalitis and Guillain-Barré syndrome in adults. Neurotropic viruses often use axons to traffic to neuronal or glial cell somas where they either remain latent or replicate and proceed to infect new cells. Consequently, it has been suggested that axon degeneration could represent an evolutionarily conserved mechanism to limit viral spread. Whilst it is not known if ZIKV transits in axons, we previously reported that ZIKV infection of glial cells in a murine spinal cord-derived cell culture model of the CNS is associated with a profound loss of neuronal cell processes. This, despite that postmitotic neurons are relatively refractory to infection and death. Here, we tested the hypothesis that ZIKV-associated degeneration of neuronal processes is dependent on activation of Sterile alpha and armadillo motif-containing protein 1 (SARM1), an NADase that acts as a central executioner in a conserved axon degeneration pathway. To test this, we infected wild type and Sarm1 homozygous or heterozygous null cell cultures with ZIKV and examined NAD+ levels as well as the survival of neurons and their processes. Unexpectedly, ZIKV infection led to a rapid SARM1-independent reduction in NAD+. Nonetheless, the subsequent profound loss of neuronal cell processes was SARM1-dependent and was preceded by early changes in the appearance of β-tubulin III staining. Together, these data identify a role for SARM1 in the pathogenesis of ZIKV infection, which may reflect SARM1's conserved prodegenerative function, independent of its NADase activity.
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Affiliation(s)
- Colin L. Crawford
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | | | - Lina Komarek
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Verena Schultz
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Claire L. Donald
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Paul Montague
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Susan C. Barnett
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Christopher Linington
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Hugh J. Willison
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Alain Kohl
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Michael P. Coleman
- John van Geest Centre for Brain Repair, Cambridge, United Kingdom
- Michael P. Coleman
| | - Julia M. Edgar
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
- *Correspondence: Julia M. Edgar
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9
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Edgar JM, McGowan E, Chapple KJ, Möbius W, Lemgruber L, Insall RH, Nave K, Boullerne A. Río-Hortega's drawings revisited with fluorescent protein defines a cytoplasm-filled channel system of CNS myelin. J Anat 2021; 239:1241-1255. [PMID: 34713444 PMCID: PMC8602028 DOI: 10.1111/joa.13577] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 10/10/2021] [Accepted: 10/11/2021] [Indexed: 01/13/2023] Open
Abstract
A century ago this year, Pío del Río-Hortega (1921) coined the term 'oligodendroglia' for the 'interfascicular glia' with very few processes, launching an extensive discovery effort on his new cell type. One hundred years later, we review his original contributions to our understanding of the system of cytoplasmic channels within myelin in the context of what we observe today using light and electron microscopy of genetically encoded fluorescent reporters and immunostaining. We use the term myelinic channel system to describe the cytoplasm-delimited spaces associated with myelin; being the paranodal loops, inner and outer tongues, cytoplasm-filled spaces through compact myelin and further complex motifs associated to the sheath. Using a central nervous system myelinating cell culture model that contains all major neural cell types and produces compact myelin, we find that td-tomato fluorescent protein delineates the myelinic channel system in a manner reminiscent of the drawings of adult white matter by Río-Hortega, despite that he questioned whether some cytoplasmic figures he observed represented artefact. Together, these data lead us to propose a slightly revised model of the 'unrolled' sheath. Further, we show that the myelinic channel system, while relatively stable, can undergo subtle dynamic shape changes over days. Importantly, we capture an under-appreciated complexity of the myelinic channel system in mature myelin sheaths.
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Affiliation(s)
- Julia M. Edgar
- Axo‐Glial GroupInstitute of Infection, Immunity and InflammationCollege of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
- Department of NeurogeneticsMax Planck Institute of Experimental MedicineGöttingenGermany
| | - Eleanor McGowan
- Axo‐Glial GroupInstitute of Infection, Immunity and InflammationCollege of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
| | - Katie J. Chapple
- Axo‐Glial GroupInstitute of Infection, Immunity and InflammationCollege of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
| | - Wiebke Möbius
- Department of NeurogeneticsMax Planck Institute of Experimental MedicineGöttingenGermany
- Electron Microscopy Core UnitMax Planck Institute of Experimental MedicineGöttingenGermany
| | - Leandro Lemgruber
- Glasgow Imaging FacilityInstitute of Infection, Immunity and InflammationCollege of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
| | | | - Klaus‐Armin Nave
- Department of NeurogeneticsMax Planck Institute of Experimental MedicineGöttingenGermany
| | - Anne Boullerne
- Department of AnesthesiologyUniversity of Illinois at ChicagoChicagoIllinoisUSA
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10
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Berghoff SA, Spieth L, Sun T, Hosang L, Depp C, Sasmita AO, Vasileva MH, Scholz P, Zhao Y, Krueger-Burg D, Wichert S, Brown ER, Michail K, Nave KA, Bonn S, Odoardi F, Rossner M, Ischebeck T, Edgar JM, Saher G. Neuronal cholesterol synthesis is essential for repair of chronically demyelinated lesions in mice. Cell Rep 2021; 37:109889. [PMID: 34706227 DOI: 10.1016/j.celrep.2021.109889] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 08/12/2021] [Accepted: 10/05/2021] [Indexed: 11/15/2022] Open
Abstract
Astrocyte-derived cholesterol supports brain cells under physiological conditions. However, in demyelinating lesions, astrocytes downregulate cholesterol synthesis, and the cholesterol that is essential for remyelination has to originate from other cellular sources. Here, we show that repair following acute versus chronic demyelination involves distinct processes. In particular, in chronic myelin disease, when recycling of lipids is often defective, de novo neuronal cholesterol synthesis is critical for regeneration. By gene expression profiling, genetic loss-of-function experiments, and comprehensive phenotyping, we provide evidence that neurons increase cholesterol synthesis in chronic myelin disease models and in patients with multiple sclerosis (MS). In mouse models, neuronal cholesterol facilitates remyelination specifically by triggering oligodendrocyte precursor cell proliferation. Our data contribute to the understanding of disease progression and have implications for therapeutic strategies in patients with MS.
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Affiliation(s)
- Stefan A Berghoff
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.
| | - Lena Spieth
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Ting Sun
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany; Institute for Medical Systems Biology, Center for Molecular Neurobiology Hamburg, Hamburg, Germany
| | - Leon Hosang
- Institute for Neuroimmunology and Multiple Sclerosis Research, University Medical Center Göttingen, Göttingen, Germany
| | - Constanze Depp
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Andrew O Sasmita
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Martina H Vasileva
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Patricia Scholz
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences and Göttingen Center for Molecular Biosciences (GZMB), University of Göttingen, Göttingen, Germany
| | - Yu Zhao
- Institute for Medical Systems Biology, Center for Molecular Neurobiology Hamburg, Hamburg, Germany
| | - Dilja Krueger-Burg
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Sven Wichert
- Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, Munich, Germany
| | - Euan R Brown
- School of Engineering and Physical Sciences, Institute of Biological Chemistry, Biophysics and Bioengineering, James Naysmith Building, Heriot Watt University, Edinburgh, UK
| | - Kyriakos Michail
- School of Engineering and Physical Sciences, Institute of Biological Chemistry, Biophysics and Bioengineering, James Naysmith Building, Heriot Watt University, Edinburgh, UK
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Stefan Bonn
- Institute for Medical Systems Biology, Center for Molecular Neurobiology Hamburg, Hamburg, Germany
| | - Francesca Odoardi
- Institute for Neuroimmunology and Multiple Sclerosis Research, University Medical Center Göttingen, Göttingen, Germany
| | - Moritz Rossner
- Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, Munich, Germany
| | - Till Ischebeck
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences and Göttingen Center for Molecular Biosciences (GZMB), University of Göttingen, Göttingen, Germany; Service Unit for Metabolomics and Lipidomics, Göttingen Center for Molecular Biosciences (GZMB), University of Göttingen, Göttingen, Germany
| | - Julia M Edgar
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany; Axo-glial Group, Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Gesine Saher
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.
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11
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Schultz V, Barrie JA, Donald CL, Crawford CL, Mullin M, Anderson TJ, Solomon T, Barnett SC, Linington C, Kohl A, Willison HJ, Edgar JM. Oligodendrocytes are susceptible to Zika virus infection in a mouse model of perinatal exposure: Implications for CNS complications. Glia 2021; 69:2023-2036. [PMID: 33942402 PMCID: PMC9216243 DOI: 10.1002/glia.24010] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 04/05/2021] [Accepted: 04/08/2021] [Indexed: 12/22/2022]
Abstract
Some children with proven intrauterine Zika virus (ZIKV) infection who were born asymptomatic subsequently manifested neurodevelopmental delays, pointing to impairment of development perinatally and postnatally. To model this, we infected postnatal day (P) 5-6 (equivalent to the perinatal period in humans) susceptible mice with a mammalian cell-propagated ZIKV clinical isolate from the Brazilian outbreak in 2015. All infected mice appeared normal up to 4 days post-intraperitoneal inoculation (dpi), but rapidly developed severe clinical signs at 5-6 dpi. All nervous tissue examined at 5/6 dpi appeared grossly normal. However, anti-ZIKV positive cells were observed in the optic nerve, brain, and spinal cord; predominantly in white matter. Co-labeling with cell type specific markers demonstrated oligodendrocytes and astrocytes support productive infection. Rarely, ZIKV positive neurons were observed. In spinal cord white matter, which we examined in detail, apoptotic cells were evident; the density of oligodendrocytes was significantly reduced; and there was localized microglial reactivity including expression of the NLRP3 inflammasome. Together, our observations demonstrate that a clinically relevant ZIKV isolate can directly impact oligodendrocytes. As primary oligodendrocyte cell death can lead later to secondary autoimmune demyelination, our observations may help explain neurodevelopmental delays in infants appearing asymptomatic at birth and commend lifetime surveillance.
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Affiliation(s)
- Verena Schultz
- College of Medical, Veterinary, and Life Sciences, Institute of Infection, Immunity and Inflammation, Glasgow, UK
| | - Jennifer A Barrie
- College of Medical, Veterinary, and Life Sciences, Institute of Infection, Immunity and Inflammation, Glasgow, UK
| | - Claire L Donald
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
| | - Colin L Crawford
- College of Medical, Veterinary, and Life Sciences, Institute of Infection, Immunity and Inflammation, Glasgow, UK
| | - Margaret Mullin
- College of Medical, Veterinary, and Life Sciences, Institute of Infection, Immunity and Inflammation, Glasgow, UK
| | - Thomas J Anderson
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, Glasgow
| | - Tom Solomon
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Susan C Barnett
- College of Medical, Veterinary, and Life Sciences, Institute of Infection, Immunity and Inflammation, Glasgow, UK
| | - Christopher Linington
- College of Medical, Veterinary, and Life Sciences, Institute of Infection, Immunity and Inflammation, Glasgow, UK
| | - Alain Kohl
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
| | - Hugh J Willison
- College of Medical, Veterinary, and Life Sciences, Institute of Infection, Immunity and Inflammation, Glasgow, UK
| | - Julia M Edgar
- College of Medical, Veterinary, and Life Sciences, Institute of Infection, Immunity and Inflammation, Glasgow, UK
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12
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Berghoff SA, Spieth L, Sun T, Hosang L, Schlaphoff L, Depp C, Düking T, Winchenbach J, Neuber J, Ewers D, Scholz P, van der Meer F, Cantuti-Castelvetri L, Sasmita AO, Meschkat M, Ruhwedel T, Möbius W, Sankowski R, Prinz M, Huitinga I, Sereda MW, Odoardi F, Ischebeck T, Simons M, Stadelmann-Nessler C, Edgar JM, Nave KA, Saher G. Microglia facilitate repair of demyelinated lesions via post-squalene sterol synthesis. Nat Neurosci 2021; 24:47-60. [PMID: 33349711 PMCID: PMC7116742 DOI: 10.1038/s41593-020-00757-6] [Citation(s) in RCA: 113] [Impact Index Per Article: 37.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 11/12/2020] [Indexed: 01/23/2023]
Abstract
The repair of inflamed, demyelinated lesions as in multiple sclerosis (MS) necessitates the clearance of cholesterol-rich myelin debris by microglia/macrophages and the switch from a pro-inflammatory to an anti-inflammatory lesion environment. Subsequently, oligodendrocytes increase cholesterol levels as a prerequisite for synthesizing new myelin membranes. We hypothesized that lesion resolution is regulated by the fate of cholesterol from damaged myelin and oligodendroglial sterol synthesis. By integrating gene expression profiling, genetics and comprehensive phenotyping, we found that, paradoxically, sterol synthesis in myelin-phagocytosing microglia/macrophages determines the repair of acutely demyelinated lesions. Rather than producing cholesterol, microglia/macrophages synthesized desmosterol, the immediate cholesterol precursor. Desmosterol activated liver X receptor (LXR) signaling to resolve inflammation, creating a permissive environment for oligodendrocyte differentiation. Moreover, LXR target gene products facilitated the efflux of lipid and cholesterol from lipid-laden microglia/macrophages to support remyelination by oligodendrocytes. Consequently, pharmacological stimulation of sterol synthesis boosted the repair of demyelinated lesions, suggesting novel therapeutic strategies for myelin repair in MS.
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Affiliation(s)
- Stefan A Berghoff
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Lena Spieth
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Ting Sun
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
- Institute for Medical Systems Biology, Center for Molecular Neurobiology Hamburg, Hamburg, Germany
| | - Leon Hosang
- Institute for Neuroimmunology and Multiple Sclerosis Research, University Medical Center Göttingen, Göttingen, Germany
| | - Lennart Schlaphoff
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Constanze Depp
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Tim Düking
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Jan Winchenbach
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Jonathan Neuber
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - David Ewers
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
- Department of Clinical Neurophysiology, University Medical Centre Göttingen, Göttingen, Germany
- Department of Neurology, University Medical Centre, Göttingen, Germany
| | - Patricia Scholz
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences and Göttingen Center for Molecular Biosciences (GZMB), University of Göttingen, Göttingen, Germany
| | | | - Ludovico Cantuti-Castelvetri
- Institute of Neuronal Cell Biology, Technical University Munich, German Center for Neurodegenerative Diseases, Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
| | - Andrew O Sasmita
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Martin Meschkat
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Torben Ruhwedel
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Roman Sankowski
- Institute of Neuropathology, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Marco Prinz
- Institute of Neuropathology, Medical Faculty, University of Freiburg, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
- Center for Basics in NeuroModulation (NeuroModul Basics), Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Inge Huitinga
- Neuroimmunology Research Group, Netherlands Institute for Neuroscience, an institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, the Netherlands
| | - Michael W Sereda
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
- Department of Clinical Neurophysiology, University Medical Centre Göttingen, Göttingen, Germany
- Department of Neurology, University Medical Centre, Göttingen, Germany
| | - Francesca Odoardi
- Institute for Neuroimmunology and Multiple Sclerosis Research, University Medical Center Göttingen, Göttingen, Germany
| | - Till Ischebeck
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences and Göttingen Center for Molecular Biosciences (GZMB), University of Göttingen, Göttingen, Germany
- Service Unit for Metabolomics and Lipidomics, Göttingen Center for Molecular Biosciences (GZMB), University of Göttingen, Göttingen, Germany
| | - Mikael Simons
- Institute of Neuronal Cell Biology, Technical University Munich, German Center for Neurodegenerative Diseases, Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
| | | | - Julia M Edgar
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
- Applied Neurobiology Group, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.
| | - Gesine Saher
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.
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13
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Gruenenfelder FI, McLaughlin M, Griffiths IR, Garbern J, Thomson G, Kuzman P, Barrie JA, McCulloch ML, Penderis J, Stassart R, Nave KA, Edgar JM. Neural stem cells restore myelin in a demyelinating model of Pelizaeus-Merzbacher disease. Brain 2020; 143:1383-1399. [PMID: 32419025 PMCID: PMC7462093 DOI: 10.1093/brain/awaa080] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 01/20/2020] [Accepted: 02/05/2020] [Indexed: 12/13/2022] Open
Abstract
Pelizaeus-Merzbacher disease is a fatal X-linked leukodystrophy caused by mutations in the PLP1 gene, which is expressed in the CNS by oligodendrocytes. Disease onset, symptoms and mortality span a broad spectrum depending on the nature of the mutation and thus the degree of CNS hypomyelination. In the absence of an effective treatment, direct cell transplantation into the CNS to restore myelin has been tested in animal models of severe forms of the disease with failure of developmental myelination, and more recently, in severely affected patients with early disease onset due to point mutations in the PLP1 gene, and absence of myelin by MRI. In patients with a PLP1 duplication mutation, the most common cause of Pelizaeus-Merzbacher disease, the pathology is poorly defined because of a paucity of autopsy material. To address this, we examined two elderly patients with duplication of PLP1 in whom the overall syndrome, including end-stage pathology, indicated a complex disease involving dysmyelination, demyelination and axonal degeneration. Using the corresponding Plp1 transgenic mouse model, we then tested the capacity of transplanted neural stem cells to restore myelin in the context of PLP overexpression. Although developmental myelination and axonal coverage by endogenous oligodendrocytes was extensive, as assessed using electron microscopy (n = 3 at each of four end points) and immunostaining (n = 3 at each of four end points), wild-type neural precursors, transplanted into the brains of the newborn mutants, were able to effectively compete and replace the defective myelin (n = 2 at each of four end points). These data demonstrate the potential of neural stem cell therapies to restore normal myelination and protect axons in patients with PLP1 gene duplication mutation and further, provide proof of principle for the benefits of stem cell transplantation for other fatal leukodystrophies with 'normal' developmental myelination.
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Affiliation(s)
- Fredrik I Gruenenfelder
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Mark McLaughlin
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Ian R Griffiths
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - James Garbern
- Department of Neurology and Center for Molecular Medicine and Genetics, Wayne State University, Detroit, MI 48201, USA
| | - Gemma Thomson
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Peter Kuzman
- Department of Neuropathology, University Clinic Leipzig, D-04103 Leipzig, Germany
| | - Jennifer A Barrie
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK.,Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, G12 8TA, UK
| | - Maj-Lis McCulloch
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Jacques Penderis
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Ruth Stassart
- Department of Neuropathology, University Clinic Leipzig, D-04103 Leipzig, Germany
| | - Klaus-Armin Nave
- Max Planck Institute for Experimental Medicine, D-37075 Goettingen, Germany
| | - Julia M Edgar
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK.,Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, G12 8TA, UK.,Max Planck Institute for Experimental Medicine, D-37075 Goettingen, Germany
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14
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Hayden L, Semenoff T, Schultz V, Merz SF, Chapple KJ, Rodriguez M, Warrington AE, Shi X, McKimmie CS, Edgar JM, Thümmler K, Linington C, Pingen M. Lipid-specific IgMs induce antiviral responses in the CNS: implications for progressive multifocal leukoencephalopathy in multiple sclerosis. Acta Neuropathol Commun 2020; 8:135. [PMID: 32792006 PMCID: PMC7427287 DOI: 10.1186/s40478-020-01011-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 08/01/2020] [Indexed: 01/07/2023] Open
Abstract
Progressive multi-focal leukoencephalopathy (PML) is a potentially fatal encephalitis caused by JC polyomavirus (JCV). PML principally affects people with a compromised immune system, such as patients with multiple sclerosis (MS) receiving treatment with natalizumab. However, intrathecal synthesis of lipid-reactive IgM in MS patients is associated with a markedly lower incidence of natalizumab-associated PML compared to those without this antibody repertoire. Here we demonstrate that a subset of lipid-reactive human and murine IgMs induce a functional anti-viral response that inhibits replication of encephalitic Alpha and Orthobunyaviruses in multi-cellular central nervous system cultures. These lipid-specific IgMs trigger microglia to produce IFN-β in a cGAS-STING-dependent manner, which induces an IFN-α/β-receptor 1-dependent antiviral response in glia and neurons. These data identify lipid-reactive IgM as a mediator of anti-viral activity in the nervous system and provide a rational explanation why intrathecal synthesis of lipid-reactive IgM correlates with a reduced incidence of iatrogenic PML in MS.
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15
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Wilder-Smith A, Preet R, Brickley EB, Ximenes RADA, Miranda-Filho DDB, Turchi Martelli CM, Araújo TVBD, Montarroyos UR, Moreira ME, Turchi MD, Solomon T, Jacobs BC, Villamizar CP, Osorio L, de Filipps AMB, Neyts J, Kaptein S, Huits R, Ariën KK, Willison HJ, Edgar JM, Barnett SC, Peeling R, Boeras D, Guzman MG, de Silva AM, Falconar AK, Romero-Vivas C, Gaunt MW, Sette A, Weiskopf D, Lambrechts L, Dolk H, Morris JK, Orioli IM, O'Reilly KM, Yakob L, Rocklöv J, Soares C, Ferreira MLB, Franca RFDO, Precioso AR, Logan J, Lang T, Jamieson N, Massad E. ZikaPLAN: addressing the knowledge gaps and working towards a research preparedness network in the Americas. Glob Health Action 2020; 12:1666566. [PMID: 31640505 PMCID: PMC6818126 DOI: 10.1080/16549716.2019.1666566] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Zika Preparedness Latin American Network (ZikaPLAN) is a research consortium funded by the European Commission to address the research gaps in combating Zika and to establish a sustainable network with research capacity building in the Americas. Here we present a report on ZikaPLAN`s mid-term achievements since its initiation in October 2016 to June 2019, illustrating the research objectives of the 15 work packages ranging from virology, diagnostics, entomology and vector control, modelling to clinical cohort studies in pregnant women and neonates, as well as studies on the neurological complications of Zika infections in adolescents and adults. For example, the Neuroviruses Emerging in the Americas Study (NEAS) has set up more than 10 clinical sites in Colombia. Through the Butantan Phase 3 dengue vaccine trial, we have access to samples of 17,000 subjects in 14 different geographic locations in Brazil. To address the lack of access to clinical samples for diagnostic evaluation, ZikaPLAN set up a network of quality sites with access to well-characterized clinical specimens and capacity for independent evaluations. The International Committee for Congenital Anomaly Surveillance Tools was formed with global representation from regional networks conducting birth defects surveillance. We have collated a comprehensive inventory of resources and tools for birth defects surveillance, and developed an App for low resource regions facilitating the coding and description of all major externally visible congenital anomalies including congenital Zika syndrome. Research Capacity Network (REDe) is a shared and open resource centre where researchers and health workers can access tools, resources and support, enabling better and more research in the region. Addressing the gap in research capacity in LMICs is pivotal in ensuring broad-based systems to be prepared for the next outbreak. Our shared and open research space through REDe will be used to maximize the transfer of research into practice by summarizing the research output and by hosting the tools, resources, guidance and recommendations generated by these studies. Leveraging on the research from this consortium, we are working towards a research preparedness network.
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Affiliation(s)
| | - Raman Preet
- Department of Epidemiology and Global Health, Umeå University , Umeå , Sweden
| | | | - Ricardo Arraes de Alencar Ximenes
- Departamento de Medicina Tropical, Universidade Federal de Pernambuco , Recife , Brasil.,Departamento de Medicina Interna, Universidade de Pernambuco , Recife , Brasil
| | | | | | | | | | | | - Marília Dalva Turchi
- Instituto de Patologia Tropical e Saúde Publica, Universidade Federal de Goiás , Goiânia , Brasil
| | - Tom Solomon
- Institute of Infection and Global Health, The University of Liverpool , Liverpool , UK
| | - Bart C Jacobs
- Departments of Neurology and Immunology, Erasmus Universitair Medisch Centrum Rotterdam , The Netherlands
| | | | | | | | - Johan Neyts
- Department of Microbiology, Immunology and Transplantation, KU Leuven, Rega Institute of Medical Research , Leuven , Belgium
| | - Suzanne Kaptein
- Department of Microbiology, Immunology and Transplantation, KU Leuven, Rega Institute of Medical Research , Leuven , Belgium
| | - Ralph Huits
- Institute of Tropical Medicine , Antwerp , Belgium
| | | | - Hugh J Willison
- Institute of Infection, Immunity & Inflammation, University of Glasgow , Glasgow , UK
| | - Julia M Edgar
- Institute of Infection, Immunity & Inflammation, University of Glasgow , Glasgow , UK
| | - Susan C Barnett
- Institute of Infection, Immunity & Inflammation, University of Glasgow , Glasgow , UK
| | | | - Debi Boeras
- London School of Hygiene & Tropical Medicine , London , UK
| | | | - Aravinda M de Silva
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill , NC , USA
| | - Andrew K Falconar
- London School of Hygiene & Tropical Medicine , London , UK.,Departmento del Medicina, Fundacion Universidad del Norte , Barranquilla , Colombia
| | - Claudia Romero-Vivas
- Departmento del Medicina, Fundacion Universidad del Norte , Barranquilla , Colombia
| | | | - Alessandro Sette
- Division of Vaccine Discovery, La Jolla Institute for Allergy and Immunology , La Jolla , CA , USA.,Department of Medicine, University of California San Diego , La Jolla , CA , USA
| | - Daniela Weiskopf
- Division of Vaccine Discovery, La Jolla Institute for Allergy and Immunology , La Jolla , CA , USA
| | - Louis Lambrechts
- Insect-Virus Interactions Unit, Institut Pasteur, UMR2000, CNRS , Paris , France
| | - Helen Dolk
- Maternal Fetal and Infant Research Centre, Institute of Nursing and Health Research, Ulster University , Newtownabbey , UK
| | - Joan K Morris
- Population Health Research Institute, St George's, University of London , London , UK
| | - Ieda M Orioli
- Associação Técnico-Científica Estudo Colaborativo Latino Americano de Malformações Congênitas (ECLAMC) no Departmento de Genética, Instituto de Biologia, Universidade Federal do Rio de Janeiro , Rio de Janeiro , Brazil
| | | | - Laith Yakob
- London School of Hygiene & Tropical Medicine , London , UK
| | - Joacim Rocklöv
- Department of Epidemiology and Global Health, Umeå University , Umeå , Sweden
| | - Cristiane Soares
- Hospital Federal dos Servidores do Estado , Rio de Janeiro , Brazil
| | | | | | - Alexander R Precioso
- Instituto Butantan , Brazil.,Pediatrics Department, Medical School of University of Sao Paulo , Sao Paulo , Brazil
| | - James Logan
- London School of Hygiene & Tropical Medicine , London , UK
| | - Trudie Lang
- The Global Health Network, Masters and Scholars of the University of Oxford , Oxford , UK
| | - Nina Jamieson
- The Global Health Network, Masters and Scholars of the University of Oxford , Oxford , UK
| | - Eduardo Massad
- Fundacao de Apoio a Universidade de Sao Paulo , Sao Paulo , Brazil.,School of Applied Mathematics, Fundacao Getulio Vargas , Rio de Janeiro , Brazil
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16
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Hulme H, Meikle LM, Strittmatter N, van der Hooft JJJ, Swales J, Bragg RA, Villar VH, Ormsby MJ, Barnes S, Brown SL, Dexter A, Kamat MT, Komen JC, Walker D, Milling S, Osterweil EK, MacDonald AS, Schofield CJ, Tardito S, Bunch J, Douce G, Edgar JM, Edrada-Ebel R, Goodwin RJA, Burchmore R, Wall DM. Microbiome-derived carnitine mimics as previously unknown mediators of gut-brain axis communication. Sci Adv 2020; 6:eaax6328. [PMID: 32195337 PMCID: PMC7065903 DOI: 10.1126/sciadv.aax6328] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 12/13/2019] [Indexed: 05/06/2023]
Abstract
Alterations to the gut microbiome are associated with various neurological diseases, yet evidence of causality and identity of microbiome-derived compounds that mediate gut-brain axis interaction remain elusive. Here, we identify two previously unknown bacterial metabolites 3-methyl-4-(trimethylammonio)butanoate and 4-(trimethylammonio)pentanoate, structural analogs of carnitine that are present in both gut and brain of specific pathogen-free mice but absent in germ-free mice. We demonstrate that these compounds are produced by anaerobic commensal bacteria from the family Lachnospiraceae (Clostridiales) family, colocalize with carnitine in brain white matter, and inhibit carnitine-mediated fatty acid oxidation in a murine cell culture model of central nervous system white matter. This is the first description of direct molecular inter-kingdom exchange between gut prokaryotes and mammalian brain cells, leading to inhibition of brain cell function.
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Affiliation(s)
- Heather Hulme
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Lynsey M. Meikle
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Nicole Strittmatter
- Imaging and data Analytics, Clinical Pharmacology and Safety Sciences, R&D, AstraZeneca, Cambridge CB4 0WG, UK
| | | | - John Swales
- Imaging and data Analytics, Clinical Pharmacology and Safety Sciences, R&D, AstraZeneca, Cambridge CB4 0WG, UK
| | - Ryan A. Bragg
- Pharmaceutical Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge CB4 0WG, UK
| | - Victor H. Villar
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
| | - Michael J. Ormsby
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Stephanie Barnes
- Centre for Discovery Brain Sciences, Simons Initiative for the Developing Brain, and The Patrick Wild Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Sheila L. Brown
- Lydia Becker Institute of Immunology and Inflammation, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester M13 9NT, UK
| | - Alex Dexter
- National Physical Laboratory, Teddington, Middlesex TW11 0LW, UK
| | - Maya T. Kamat
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Jasper C. Komen
- Oncology Safety, Clinical Pharmacology and Safety Sciences, R&D, AstraZeneca, Cambridge CB4 0WG, UK
| | - Daniel Walker
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Simon Milling
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Emily K. Osterweil
- Centre for Discovery Brain Sciences, Simons Initiative for the Developing Brain, and The Patrick Wild Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Andrew S. MacDonald
- Lydia Becker Institute of Immunology and Inflammation, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester M13 9NT, UK
| | - Chris J. Schofield
- Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, UK
| | - Saverio Tardito
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
- Institute of Cancer Sciences, University of Glasgow, Glasgow G61 1QH, UK
| | - Josephine Bunch
- National Physical Laboratory, Teddington, Middlesex TW11 0LW, UK
- Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Sir Alexander Fleming Building, South Kensington Campus, London SW7 2AZ, UK
| | - Gillian Douce
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Julia M. Edgar
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
- Department of Neurogenetics, Max Planck Institute for Experimental Medicine, Hermann-Rein-Strasse 3, D-37075 Goettingen, Germany
| | - RuAngelie Edrada-Ebel
- Natural Products Metabolomics Group, Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, UK
| | - Richard J. A. Goodwin
- Imaging and data Analytics, Clinical Pharmacology and Safety Sciences, R&D, AstraZeneca, Cambridge CB4 0WG, UK
| | - Richard Burchmore
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Daniel M. Wall
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
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17
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Abstract
Transmission electron microscopy of central nervous system white matter has provided unparalleled access to the ultrastructural features of axons, their myelin sheaths, and the major cells of white matter; namely, oligodendrocytes, oligodendrocyte precursors, astrocytes, and microglia. In particular, it has been invaluable in elucidating pathological changes in axons and myelin following experimentally induced injury or genetic alteration, in animal models. While also of value in the examination of human white matter, the tissue is rarely fixed adequately for the types of detailed analyses that can be performed on well-preserved samples from animal models, perfusion fixed at the time of death. In this chapter we describe methods for obtaining, processing, and visualizing white matter samples using transmission electron microscopy of perfusion fixed tissue and for unbiased morphometry of white matter, with particular emphasis on axon and myelin pathology. Several advanced electron microscopy techniques are now available, but this method remains the most expedient and accessible for routine ultrastructural examination and morphometry.
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Affiliation(s)
- Julia M Edgar
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.
- Department of Neurogenetics, Max Planck Institute for Experimental Medicine, Goettingen, Germany.
| | - Rebecca Sherrard Smith
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Ian D Duncan
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA
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18
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Thümmler K, Rom E, Zeis T, Lindner M, Brunner S, Cole JJ, Arseni D, Mücklisch S, Edgar JM, Schaeren-Wiemers N, Yayon A, Linington C. Polarizing receptor activation dissociates fibroblast growth factor 2 mediated inhibition of myelination from its neuroprotective potential. Acta Neuropathol Commun 2019; 7:212. [PMID: 31856924 PMCID: PMC6923900 DOI: 10.1186/s40478-019-0864-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 12/03/2019] [Indexed: 02/07/2023] Open
Abstract
Fibroblast growth factor (FGF) signaling contributes to failure of remyelination in multiple sclerosis, but targeting this therapeutically is complicated by its functional pleiotropy. We now identify FGF2 as a factor up-regulated by astrocytes in active inflammatory lesions that disrupts myelination via FGF receptor 2 (FGFR2) mediated activation of Wingless (Wnt) signaling; pharmacological inhibition of Wnt being sufficient to abrogate inhibition of myelination by FGF2 in tissue culture. Using a novel FGFR1-selective agonist (F2 V2) generated by deleting the N-terminal 26 amino acids of FGF2 we demonstrate polarizing signal transduction to favor FGFR1 abrogates FGF mediated inhibition of myelination but retains its ability to induce expression of pro-myelinating and immunomodulatory factors that include Cd93, Lif, Il11, Hbegf, Cxcl1 and Timp1. Our data provide new insights into the mechanistic basis of remyelination failure in MS and identify selective activation of FGFR1 as a novel strategy to induce a neuroprotective signaling environment in multiple sclerosis and other neurological diseases.
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19
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Abstract
Regulatory T cells (Tregs) are important for limiting inflammation-dependent damage in neural tissue. However, Tregs have also been shown to inhibit neural repair associated with type 2 (anti-inflammatory/wound healing) immune responses. Recently, it was demonstrated that Sirtuins, a family of proteins that contribute to the control of cellular responses to metabolic stimuli, influence the functions of Tregs. Specifically, SIRT4 was found to suppress the anti-neuroinflammatory activity of Tregs infiltrating the spinal cord following injury; when SIRT4 expression was genetically suppressed, Tregs made more anti-inflammatory factors, IL-10, FoxP3, and transforming growth factor beta (TGFβ). Thus, understanding how the SIRT4-Treg pathway can be manipulated could provide useful avenues to control both pathogenic and neuroprotective immune responses.
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Affiliation(s)
- Simon Milling
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK
| | - Julia M Edgar
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK
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20
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Bijland S, Thomson G, Euston M, Michail K, Thümmler K, Mücklisch S, Crawford CL, Barnett SC, McLaughlin M, Anderson TJ, Linington C, Brown ER, Kalkman ER, Edgar JM. An in vitro model for studying CNS white matter: functional properties and experimental approaches. F1000Res 2019; 8:117. [PMID: 31069065 PMCID: PMC6489523 DOI: 10.12688/f1000research.16802.1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/15/2019] [Indexed: 12/23/2022] Open
Abstract
The normal development and maintenance of CNS white matter, and its responses to disease and injury, are defined by synergies between axons, oligodendrocytes, astrocytes and microglia, and further influenced by peripheral components such as the gut microbiome and the endocrine and immune systems. Consequently, mechanistic insights, therapeutic approaches and safety tests rely ultimately on in vivo models and clinical trials. However, in vitro models that replicate the cellular complexity of the CNS can inform these approaches, reducing costs and minimising the use of human material or experimental animals; in line with the principles of the 3Rs. Using electrophysiology, pharmacology, time-lapse imaging, and immunological assays, we demonstrate that murine spinal cord-derived myelinating cell cultures recapitulate spinal-like electrical activity and innate CNS immune functions, including responses to disease-relevant myelin debris and pathogen associated molecular patterns (PAMPs). Further, we show they are (i) amenable to siRNA making them suitable for testing gene-silencing strategies; (ii) can be established on microelectrode arrays (MEAs) for electrophysiological studies; and (iii) are compatible with multi-well microplate formats for semi-high throughput screens, maximising information output whilst further reducing animal use. We provide protocols for each of these. Together, these advances increase the utility of this in vitro tool for studying normal and pathological development and function of white matter, and for screening therapeutic molecules or gene targets for diseases such as multiple sclerosis, motor neuron disease or spinal cord injury, whilst avoiding in vivo approaches on experimental animals.
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Affiliation(s)
- Silvia Bijland
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Gemma Thomson
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Matthew Euston
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Kyriakos Michail
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, Edinburgh, EH14 4AS, UK
| | - Katja Thümmler
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Steve Mücklisch
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Colin L Crawford
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Susan C Barnett
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Mark McLaughlin
- School of Veterinary Medicine, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G61 1QH, UK
| | - T James Anderson
- School of Veterinary Medicine, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G61 1QH, UK
| | - Christopher Linington
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Euan R Brown
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, Edinburgh, EH14 4AS, UK
| | - Eric R Kalkman
- Institute of Cancer Sciences, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G61 1QH, UK
| | - Julia M Edgar
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
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21
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Abstract
Axons are electrically excitable, cable-like neuronal processes that relay information between neurons within the nervous system and between neurons and peripheral target tissues. In the central and peripheral nervous systems, most axons over a critical diameter are enwrapped by myelin, which reduces internodal membrane capacitance and facilitates rapid conduction of electrical impulses. The spirally wrapped myelin sheath, which is an evolutionary specialisation of vertebrates, is produced by oligodendrocytes and Schwann cells; in most mammals myelination occurs during postnatal development and after axons have established connection with their targets. Myelin covers the vast majority of the axonal surface, influencing the axon's physical shape, the localisation of molecules on its membrane and the composition of the extracellular fluid (in the periaxonal space) that immerses it. Moreover, myelinating cells play a fundamental role in axonal support, at least in part by providing metabolic substrates to the underlying axon to fuel its energy requirements. The unique architecture of the myelinated axon, which is crucial to its function as a conduit over long distances, renders it particularly susceptible to injury and confers specific survival and maintenance requirements. In this review we will describe the normal morphology, ultrastructure and function of myelinated axons, and discuss how these change following disease, injury or experimental perturbation, with a particular focus on the role the myelinating cell plays in shaping and supporting the axon.
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Affiliation(s)
- Ruth M. Stassart
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
- Department of Neuropathology, University Medical Center Leipzig, Leipzig, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
| | - Julia M. Edgar
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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22
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Bahey NG, Gadalla KKE, McGonigal R, Bailey MES, Edgar JM, Cobb SR. Reduced axonal diameter of peripheral nerve fibers in a mouse model of Rett syndrome. Neuroscience 2017; 358:261-268. [PMID: 28687309 DOI: 10.1016/j.neuroscience.2017.06.061] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 06/27/2017] [Accepted: 06/28/2017] [Indexed: 12/29/2022]
Abstract
Rett syndrome (RTT) is a neurological disorder characterized by motor and cognitive impairment, autonomic dysfunction and a loss of purposeful hand skills. In the majority of cases, typical RTT is caused by de novo mutations in the X-linked gene, MECP2. Alterations in the structure and function of neurons within the central nervous system of RTT patients and Mecp2-null mouse models are well established. In contrast, few studies have investigated the effects of MeCP2-deficiency on peripheral nerves. In this study, we conducted detailed morphometric as well as functional analysis of the sciatic nerves of symptomatic adult female Mecp2+/- mice. We observed a significant reduction in the mean diameter of myelinated nerve fibers in Mecp2+/- mice. In myelinated fibers, mitochondrial densities per unit area of axoplasm were significantly altered in Mecp2+/- mice. However, conduction properties of the sciatic nerve of Mecp2 knockout mice were not different from control. These subtle changes in myelinated peripheral nerve fibers in heterozygous Mecp2 knockout mice could potentially explain some RTT phenotypes.
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Affiliation(s)
- Noha G Bahey
- Institute of Neuroscience and Psychology, University of Glasgow, United Kingdom; Histology Department, Faculty of Medicine, Tanta University, Egypt
| | - Kamal K E Gadalla
- Institute of Neuroscience and Psychology, University of Glasgow, United Kingdom; Pharmacology Department, Faculty of Medicine, Tanta University, Egypt
| | - Rhona McGonigal
- Institute of Infection, Immunity and Inflammation College of Medical, Veterinary and Life Sciences, University of Glasgow, United Kingdom
| | - Mark E S Bailey
- School of Life Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, United Kingdom
| | - Julia M Edgar
- Institute of Infection, Immunity and Inflammation College of Medical, Veterinary and Life Sciences, University of Glasgow, United Kingdom
| | - Stuart R Cobb
- Institute of Neuroscience and Psychology, University of Glasgow, United Kingdom.
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23
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Cumberworth SL, Barrie JA, Cunningham ME, de Figueiredo DPG, Schultz V, Wilder-Smith AJ, Brennan B, Pena LJ, Freitas de Oliveira França R, Linington C, Barnett SC, Willison HJ, Kohl A, Edgar JM. Zika virus tropism and interactions in myelinating neural cell cultures: CNS cells and myelin are preferentially affected. Acta Neuropathol Commun 2017; 5:50. [PMID: 28645311 PMCID: PMC5481922 DOI: 10.1186/s40478-017-0450-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 06/02/2017] [Indexed: 12/02/2022] Open
Abstract
The recent global outbreak of Zika virus (ZIKV) infection has been linked to severe neurological disorders affecting the peripheral and central nervous systems (PNS and CNS, respectively). The pathobiology underlying these diverse clinical phenotypes are the subject of intense research; however, even the principal neural cell types vulnerable to productive Zika infection remain poorly characterised. Here we used CNS and PNS myelinating cultures from wild type and Ifnar1 knockout mice to examine neuronal and glial tropism and short-term consequences of direct infection with a Brazilian variant of ZIKV. Cell cultures were infected pre- or post-myelination for various intervals, then stained with cell-type and ZIKV-specific antibodies. In bypassing systemic immunity using ex vivo culture, and the type I interferon response in Ifnar1 deficient cells, we were able to evaluate the intrinsic infectivity of neural cells. Through systematic quantification of ZIKV infected cells in myelinating cultures, we found that ZIKV infection is enhanced in the absence of the type I interferon responses and that CNS cells are considerably more susceptible to infection than PNS cells. In particular, we demonstrate that CNS axons and myelinating oligodendrocytes are especially vulnerable to injury. These results have implications for understanding the pathobiology of neurological symptoms associated with ZIKV infection. Furthermore, we provide a quantifiable ex vivo infection model that can be used for fundamental and therapeutic studies on viral neuroinvasion and its consequences.
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Affiliation(s)
| | - Jennifer A Barrie
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, G12 8TA, Glasgow, Scotland, UK
| | - Madeleine E Cunningham
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, G12 8TA, Glasgow, Scotland, UK
| | - Daniely Paulino Gomes de Figueiredo
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, G12 8TA, Glasgow, Scotland, UK
| | - Verena Schultz
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, G12 8TA, Glasgow, Scotland, UK
| | - Adrian J Wilder-Smith
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, G12 8TA, Glasgow, Scotland, UK
| | - Benjamin Brennan
- MRC-University of Glasgow Centre for Virus Research, G61 1QH, Glasgow, Scotland, UK
| | - Lindomar J Pena
- Oswaldo Cruz Foundation/Aggeu Magalhães Institute, Department of Virology, UFPE Campus-Cidade Universitária, Recife/PE, Brazil
| | | | - Christopher Linington
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, G12 8TA, Glasgow, Scotland, UK
| | - Susan C Barnett
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, G12 8TA, Glasgow, Scotland, UK
| | - Hugh J Willison
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, G12 8TA, Glasgow, Scotland, UK
| | - Alain Kohl
- MRC-University of Glasgow Centre for Virus Research, G61 1QH, Glasgow, Scotland, UK.
| | - Julia M Edgar
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, G12 8TA, Glasgow, Scotland, UK.
- Department of Neurogenetics, Max Planck Institute for Experimental Medicine, Hermann-Rein-Strasse 3, 37075, Goettingen, Germany.
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24
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Berghoff SA, Gerndt N, Winchenbach J, Stumpf SK, Hosang L, Odoardi F, Ruhwedel T, Böhler C, Barrette B, Stassart R, Liebetanz D, Dibaj P, Möbius W, Edgar JM, Saher G. Dietary cholesterol promotes repair of demyelinated lesions in the adult brain. Nat Commun 2017; 8:14241. [PMID: 28117328 PMCID: PMC5286209 DOI: 10.1038/ncomms14241] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 12/12/2016] [Indexed: 12/15/2022] Open
Abstract
Multiple Sclerosis (MS) is an inflammatory demyelinating disorder in which remyelination failure contributes to persistent disability. Cholesterol is rate-limiting for myelin biogenesis in the developing CNS; however, whether cholesterol insufficiency contributes to remyelination failure in MS, is unclear. Here, we show the relationship between cholesterol, myelination and neurological parameters in mouse models of demyelination and remyelination. In the cuprizone model, acute disease reduces serum cholesterol levels that can be restored by dietary cholesterol. Concomitant with blood-brain barrier impairment, supplemented cholesterol directly supports oligodendrocyte precursor proliferation and differentiation, and restores the balance of growth factors, creating a permissive environment for repair. This leads to attenuated axon damage, enhanced remyelination and improved motor learning. Remarkably, in experimental autoimmune encephalomyelitis, cholesterol supplementation does not exacerbate disease expression. These findings emphasize the safety of dietary cholesterol in inflammatory diseases and point to a previously unrecognized role of cholesterol in promoting repair after demyelinating episodes. Cholesterol is important for axonal myelination during development. Here the authors show that cholesterol levels are reduced in a cuprizone mouse model of multiple sclerosis and that dietary cholesterol supplementation enhances remyelination and recovery.
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Affiliation(s)
- Stefan A Berghoff
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
| | - Nina Gerndt
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
| | - Jan Winchenbach
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
| | - Sina K Stumpf
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
| | - Leon Hosang
- Institute of Neuroimmunology and Institute for Multiple Sclerosis Research, University Medical Centre Göttingen, Waldweg 33, 37073 Göttingen, Germany
| | - Francesca Odoardi
- Institute of Neuroimmunology and Institute for Multiple Sclerosis Research, University Medical Centre Göttingen, Waldweg 33, 37073 Göttingen, Germany
| | - Torben Ruhwedel
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
| | - Carolin Böhler
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
| | - Benoit Barrette
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
| | - Ruth Stassart
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Hermann-Rein-Str. 3, 37075 Göttingen, Germany.,Department of Neuropathology, University Medical Center, Georg-August-University, Robert Koch Str. 40, 37075 Göttingen, Germany
| | - David Liebetanz
- Department of Clinical Neurophysiology, Georg-August University, Robert Koch Str. 40, 37075 Göttingen, Germany
| | - Payam Dibaj
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Hermann-Rein-Str. 3, 37075 Göttingen, Germany.,Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Wilhelmsplatz 1, 37073 Göttingen, Germany
| | - Julia M Edgar
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Hermann-Rein-Str. 3, 37075 Göttingen, Germany.,Applied Neurobiology Group, Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow G12-8TA, UK
| | - Gesine Saher
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
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25
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Abstract
In the central nervous system (CNS), myelin is formed by oligodendrocytes that are derived from precursor cells, known as oligodendrocyte precursor cells (OPCs). Successive stages of OPC interactions with the axons can be visualized in vitro and ex vivo using mixed neural cell cultures and pieces of intact spinal cord, respectively. OPCs and their differentiation can be imaged using cell-type-specific markers or green fluorescent protein (GFP) tags. This protocol describes methodology for generating these two systems for time-lapse imaging of dynamic cell interactions using fluorescent and 2-photon microscopy.
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Affiliation(s)
- Kalliopi Ioannidou
- Clinical Tumor Biology & Immunotherapy Group, Ludwig Centre for Cancer Research, Department of Oncology, University Hospital of Lausanne, Lausanne, Switzerland.,These authors contributed equally to this work
| | - Julia M Edgar
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom.,These authors contributed equally to this work
| | - Susan C Barnett
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
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26
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Lindner M, Thümmler K, Arthur A, Brunner S, Elliott C, McElroy D, Mohan H, Williams A, Edgar JM, Schuh C, Stadelmann C, Barnett SC, Lassmann H, Mücklisch S, Mudaliar M, Schaeren-Wiemers N, Meinl E, Linington C. Fibroblast growth factor signalling in multiple sclerosis: inhibition of myelination and induction of pro-inflammatory environment by FGF9. Brain 2015; 138:1875-93. [PMID: 25907862 PMCID: PMC7185739 DOI: 10.1093/brain/awv102] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 02/14/2015] [Indexed: 12/18/2022] Open
Abstract
Remyelination failure plays an important role in the pathophysiology of multiple sclerosis, but the underlying cellular and molecular mechanisms remain poorly understood. We now report actively demyelinating lesions in patients with multiple sclerosis are associated with increased glial expression of fibroblast growth factor 9 (FGF9), which we demonstrate inhibits myelination and remyelination in vitro. This inhibitory activity is associated with the appearance of multi-branched ‘pre-myelinating’ MBP+/PLP+ oligodendrocytes that interact with axons but fail to assemble myelin sheaths; an oligodendrocyte phenotype described previously in chronically demyelinated multiple sclerosis lesions. This inhibitory activity is not due to a direct effect of FGF9 on cells of the oligodendrocyte lineage but is mediated by factors secreted by astrocytes. Transcriptional profiling and functional validation studies demonstrate that these include effects dependent on increased expression of tissue inhibitor of metalloproteinase-sensitive proteases, enzymes more commonly associated with extracellular matrix remodelling. Further, we found that FGF9 induces expression of Ccl2 and Ccl7, two pro-inflammatory chemokines that contribute to recruitment of microglia and macrophages into multiple sclerosis lesions. These data indicate glial expression of FGF9 can initiate a complex astrocyte-dependent response that contributes to two distinct pathogenic pathways involved in the development of multiple sclerosis lesions. Namely, induction of a pro-inflammatory environment and failure of remyelination; a combination of effects predicted to exacerbate axonal injury and loss in patients.
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Affiliation(s)
- Maren Lindner
- 1 Institute of Infection, Immunity and Inflammation, University of Glasgow, UK
| | - Katja Thümmler
- 1 Institute of Infection, Immunity and Inflammation, University of Glasgow, UK
| | - Ariel Arthur
- 1 Institute of Infection, Immunity and Inflammation, University of Glasgow, UK
| | - Sarah Brunner
- 2 Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Christina Elliott
- 1 Institute of Infection, Immunity and Inflammation, University of Glasgow, UK
| | - Daniel McElroy
- 1 Institute of Infection, Immunity and Inflammation, University of Glasgow, UK
| | - Hema Mohan
- 3 Institute of Clinical Neuroimmunology, Ludwig-Maximilians-Universität, Munich, Germany
| | - Anna Williams
- 4 MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, UK
| | - Julia M Edgar
- 1 Institute of Infection, Immunity and Inflammation, University of Glasgow, UK
| | - Cornelia Schuh
- 5 Centre for Brain Research, Medical University of Vienna, Vienna, Austria
| | | | - Susan C Barnett
- 1 Institute of Infection, Immunity and Inflammation, University of Glasgow, UK
| | - Hans Lassmann
- 5 Centre for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Steve Mücklisch
- 7 Department of Computer Science, Chemnitz University of Technology, Chemnitz, Germany
| | - Manikhandan Mudaliar
- 8 Glasgow Polyomics, College of Medical, Veterinary and Life Science, University of Glasgow, UK
| | - Nicole Schaeren-Wiemers
- 2 Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Edgar Meinl
- 3 Institute of Clinical Neuroimmunology, Ludwig-Maximilians-Universität, Munich, Germany
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27
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Barrette B, Nave KA, Edgar JM. Molecular triggers of neuroinflammation in mouse models of demyelinating diseases. Biol Chem 2014; 394:1571-81. [PMID: 23959664 DOI: 10.1515/hsz-2013-0219] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 08/15/2013] [Indexed: 12/20/2022]
Abstract
Myelinating cells wrap axons with multi-layered myelin sheaths for rapid impulse propagation. Dysfunctions of oligodendrocytes or Schwann cells are often associated with neuroinflammation, as observed in animal models of leukodystrophies and peripheral neuropathies, respectively. The neuroinflammatory response modulates the pathological changes, including demyelination and axonal injury, but also remyelination and repair. Here we discuss different immune mechanisms as well as factors released or exposed by myelinating glia in disease conditions. The spectrum of inflammatory mediators varies with different myelin disorders and has a major impact on the beneficial or detrimental role of immune cells in keeping nervous system integrity.
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28
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Ioannidou K, Anderson KI, Strachan D, Edgar JM, Barnett SC. Astroglial-axonal interactions during early stages of myelination in mixed cultures using in vitro and ex vivo imaging techniques. BMC Neurosci 2014; 15:59. [PMID: 24886503 PMCID: PMC4024314 DOI: 10.1186/1471-2202-15-59] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 04/24/2014] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND [corrected] Myelination is a very complex process that requires the cross talk between various neural cell types. Previously, using cytosolic or membrane associated GFP tagged neurospheres, we followed the interaction of oligodendrocytes with axons using time-lapse imaging in vitro and ex vivo and demonstrated dynamic changes in cell morphology. In this study we focus on GFP tagged astrocytes differentiated from neurospheres and their interactions with axons. RESULTS We show the close interaction of astrocyte processes with axons and with oligodendrocytes in mixed mouse spinal cord cultures with formation of membrane blebs as previously seen for oligodendrocytes in the same cultures. When GFP-tagged neurospheres were transplanted into the spinal cord of the dysmyelinated shiverer mouse, confirmation of dynamic changes in cell morphology was provided and a prevalence for astrocyte differentiation compared with oligodendroglial differentiation around the injection site. Furthermore, we were able to image GFP tagged neural cells in vivo after transplantation and the cells exhibited similar membrane changes as cells visualised in vitro and ex vivo. CONCLUSION These data show that astrocytes exhibit dynamic cell process movement and changes in their membrane topography as they interact with axons and oligodendrocytes during the process of myelination, with the first demonstration of bleb formation in astrocytes.
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Affiliation(s)
| | | | | | - Julia M Edgar
- Institute of Infection, Immunity and inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Sir Graeme Davies Building, 120 University Place, Glasgow G12 8TA, UK.
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29
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Yao D, McGonigal R, Barrie JA, Cappell J, Cunningham ME, Meehan GR, Fewou SN, Edgar JM, Rowan E, Ohmi Y, Furukawa K, Furukawa K, Brophy PJ, Willison HJ. Neuronal expression of GalNAc transferase is sufficient to prevent the age-related neurodegenerative phenotype of complex ganglioside-deficient mice. J Neurosci 2014; 34:880-91. [PMID: 24431446 PMCID: PMC3891965 DOI: 10.1523/jneurosci.3996-13.2014] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 11/15/2013] [Accepted: 11/23/2013] [Indexed: 11/21/2022] Open
Abstract
Gangliosides are widely expressed sialylated glycosphingolipids with multifunctional properties in different cell types and organs. In the nervous system, they are highly enriched in both glial and neuronal membranes. Mice lacking complex gangliosides attributable to targeted ablation of the B4galnt1 gene that encodes β-1,4-N-acetylegalactosaminyltransferase 1 (GalNAc-transferase; GalNAcT(-/-)) develop normally before exhibiting an age-dependent neurodegenerative phenotype characterized by marked behavioral abnormalities, central and peripheral axonal degeneration, reduced myelin volume, and loss of axo-glial junction integrity. The cell biological substrates underlying this neurodegeneration and the relative contribution of either glial or neuronal gangliosides to the process are unknown. To address this, we generated neuron-specific and glial-specific GalNAcT rescue mice crossed on the global GalNAcT(-/-) background [GalNAcT(-/-)-Tg(neuronal) and GalNAcT(-/-)-Tg(glial)] and analyzed their behavioral, morphological, and electrophysiological phenotype. Complex gangliosides, as assessed by thin-layer chromatography, mass spectrometry, GalNAcT enzyme activity, and anti-ganglioside antibody (AgAb) immunohistology, were restored in both neuronal and glial GalNAcT rescue mice. Behaviorally, GalNAcT(-/-)-Tg(neuronal) retained a normal "wild-type" (WT) phenotype throughout life, whereas GalNAcT(-/-)-Tg(glial) resembled GalNAcT(-/-) mice, exhibiting progressive tremor, weakness, and ataxia with aging. Quantitative electron microscopy demonstrated that GalNAcT(-/-) and GalNAcT(-/-)-Tg(glial) nerves had significantly increased rates of axon degeneration and reduced myelin volume, whereas GalNAcT(-/-)-Tg(neuronal) and WT appeared normal. The increased invasion of the paranode with juxtaparanodal Kv1.1, characteristically seen in GalNAcT(-/-) and attributed to a breakdown of the axo-glial junction, was normalized in GalNAcT(-/-)-Tg(neuronal) but remained present in GalNAcT(-/-)-Tg(glial) mice. These results indicate that neuronal rather than glial gangliosides are critical to the age-related maintenance of nervous system integrity.
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Affiliation(s)
- Denggao Yao
- Institute of Infection, Immunity, and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, United Kingdom
| | - Rhona McGonigal
- Institute of Infection, Immunity, and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, United Kingdom
| | - Jennifer A. Barrie
- Institute of Infection, Immunity, and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, United Kingdom
| | - Joanna Cappell
- Institute of Infection, Immunity, and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, United Kingdom
| | - Madeleine E. Cunningham
- Institute of Infection, Immunity, and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, United Kingdom
| | - Gavin R. Meehan
- Institute of Infection, Immunity, and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, United Kingdom
| | - Simon N. Fewou
- Institute of Infection, Immunity, and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, United Kingdom
| | - Julia M. Edgar
- Institute of Infection, Immunity, and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, United Kingdom
| | - Edward Rowan
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0NR, United Kingdom
| | - Yuhsuke Ohmi
- Department of Biochemistry II, Nagoya University School of Medicine, Nagoya 466-0065, Japan, and
| | - Keiko Furukawa
- Department of Biochemistry II, Nagoya University School of Medicine, Nagoya 466-0065, Japan, and
| | - Koichi Furukawa
- Department of Biochemistry II, Nagoya University School of Medicine, Nagoya 466-0065, Japan, and
| | - Peter J. Brophy
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh EH16 4SB, United Kingdom
| | - Hugh J. Willison
- Institute of Infection, Immunity, and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, United Kingdom
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de Monasterio-Schrader P, Patzig J, Möbius W, Barrette B, Wagner TL, Kusch K, Edgar JM, Brophy PJ, Werner HB. Uncoupling of neuroinflammation from axonal degeneration in mice lacking the myelin protein tetraspanin-2. Glia 2013; 61:1832-47. [DOI: 10.1002/glia.22561] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 07/12/2013] [Accepted: 07/16/2013] [Indexed: 12/11/2022]
Affiliation(s)
| | - Julia Patzig
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen Germany
| | - Wiebke Möbius
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB); Göttingen Germany
| | - Benoit Barrette
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen Germany
| | - Tadzio L. Wagner
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen Germany
| | - Kathrin Kusch
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen Germany
| | - Julia M. Edgar
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen Germany
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow; Bearsden Road, Glasgow G61 1QH United Kingdom
| | - Peter J. Brophy
- Centre for Neuroregeneration; University of Edinburgh; United Kingdom
| | - Hauke B. Werner
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen Germany
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31
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Kolaric KV, Thomson G, Edgar JM, Brown AM. Focal axonal swellings and associated ultrastructural changes attenuate conduction velocity in central nervous system axons: a computer modeling study. Physiol Rep 2013; 1:e00059. [PMID: 24303138 PMCID: PMC3835014 DOI: 10.1002/phy2.59] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 07/22/2013] [Accepted: 07/25/2013] [Indexed: 12/11/2022] Open
Abstract
The constancy of action potential conduction in the central nervous system (CNS) relies on uniform axon diameter coupled with fidelity of the overlying myelin providing high-resistance, low capacitance insulation. Whereas the effects of demyelination on conduction have been extensively studied/modeled, equivalent studies on the repercussions for conduction of axon swelling, a common early pathological feature of (potentially reversible) axonal injury, are lacking. The recent description of experimentally acquired morphological and electrical properties of small CNS axons and oligodendrocytes prompted us to incorporate these data into a computer model, with the aim of simulating the effects of focal axon swelling on action potential conduction. A single swelling on an otherwise intact axon, as occurs in optic nerve axons of Cnp1 null mice caused a small decrease in conduction velocity. The presence of single swellings on multiple contiguous internodal regions (INR), as likely occurs in advanced disease, caused qualitatively similar results, except the dimensions of the swellings required to produce equivalent attenuation of conduction were significantly decreased. Our simulations of the consequences of metabolic insult to axons, namely, the appearance of multiple swollen regions, accompanied by perturbation of overlying myelin and increased axolemmal permeability, contained within a single INR, revealed that conduction block occurred when the dimensions of the simulated swellings were within the limits of those measured experimentally, suggesting that multiple swellings on a single axon could contribute to axonal dysfunction, and that increased axolemmal permeability is the decisive factor that promotes conduction block.
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Affiliation(s)
- Katarina V Kolaric
- School of Biomedical Sciences, Queens Medical Centre, University of Nottingham Nottingham, NG7 2UH, U.K
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32
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Ip CW, Kroner A, Groh J, Huber M, Klein D, Spahn I, Diem R, Williams SK, Nave KA, Edgar JM, Martini R. Neuroinflammation by cytotoxic T-lymphocytes impairs retrograde axonal transport in an oligodendrocyte mutant mouse. PLoS One 2012; 7:e42554. [PMID: 22905147 PMCID: PMC3414455 DOI: 10.1371/journal.pone.0042554] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 07/10/2012] [Indexed: 02/03/2023] Open
Abstract
Mice overexpressing proteolipid protein (PLP) develop a leukodystrophy-like disease involving cytotoxic, CD8+ T-lymphocytes. Here we show that these cytotoxic T-lymphocytes perturb retrograde axonal transport. Using fluorogold stereotactically injected into the colliculus superior, we found that PLP overexpression in oligodendrocytes led to significantly reduced retrograde axonal transport in retina ganglion cell axons. We also observed an accumulation of mitochondria in the juxtaparanodal axonal swellings, indicative for a disturbed axonal transport. PLP overexpression in the absence of T-lymphocytes rescued retrograde axonal transport defects and abolished axonal swellings. Bone marrow transfer from wildtype mice, but not from perforin- or granzyme B-deficient mutants, into lymphocyte-deficient PLP mutant mice led again to impaired axonal transport and the formation of axonal swellings, which are predominantly located at the juxtaparanodal region. This demonstrates that the adaptive immune system, including cytotoxic T-lymphocytes which release perforin and granzyme B, are necessary to perturb axonal integrity in the PLP-transgenic disease model. Based on our observations, so far not attended molecular and cellular players belonging to the immune system should be considered to understand pathogenesis in inherited myelin disorders with progressive axonal damage.
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Affiliation(s)
- Chi Wang Ip
- Department of Neurology, Section of Developmental Neurobiology, University of Würzburg, Würzburg, Germany
| | - Antje Kroner
- Department of Neurology, Section of Developmental Neurobiology, University of Würzburg, Würzburg, Germany
| | - Janos Groh
- Department of Neurology, Section of Developmental Neurobiology, University of Würzburg, Würzburg, Germany
| | - Marianne Huber
- Department of Neurology, Section of Developmental Neurobiology, University of Würzburg, Würzburg, Germany
| | - Dennis Klein
- Department of Neurology, Section of Developmental Neurobiology, University of Würzburg, Würzburg, Germany
| | - Irene Spahn
- Department of Neurology, Section of Developmental Neurobiology, University of Würzburg, Würzburg, Germany
| | - Ricarda Diem
- Department of Neuro-oncology, University Hospital, Heidelberg, Germany
| | - Sarah K. Williams
- Department of Neuro-oncology, University Hospital, Heidelberg, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Goettingen, Germany
| | - Julia M. Edgar
- Applied Neurobiology Group, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Rudolf Martini
- Department of Neurology, Section of Developmental Neurobiology, University of Würzburg, Würzburg, Germany
- * E-mail:
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Ioannidou K, Anderson KI, Strachan D, Edgar JM, Barnett SC. Time-lapse imaging of the dynamics of CNS glial-axonal interactions in vitro and ex vivo. PLoS One 2012; 7:e30775. [PMID: 22303455 PMCID: PMC3267745 DOI: 10.1371/journal.pone.0030775] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Accepted: 12/26/2011] [Indexed: 12/03/2022] Open
Abstract
Background Myelination is an exquisite and dynamic example of heterologous cell-cell interaction, which consists of the concentric wrapping of multiple layers of oligodendrocyte membrane around neuronal axons. Understanding the mechanism by which oligodendrocytes ensheath axons may bring us closer to designing strategies to promote remyelination in demyelinating diseases. The main aim of this study was to follow glial-axonal interactions over time both in vitro and ex vivo to visualize the various stages of myelination. Methodology/Principal Findings We took two approaches to follow myelination over time: i) time-lapse imaging of mixed CNS myelinating cultures generated from mouse spinal cord to which exogenous GFP-labelled murine cells were added, and ii) ex vivo imaging of the spinal cord of shiverer (Mbp mutant) mice, transplanted with GFP-labelled murine neurospheres. We demonstrate that oligodendrocyte-axonal interactions are dynamic events with continuous retraction and extension of oligodendroglial processes. Using cytoplasmic and membrane-GFP labelled cells to examine different components of the myelin-like sheath, we provide evidence from time-lapse fluorescence microscopy and confocal microscopy that the oligodendrocytes' cytoplasm-filled processes initially spiral around the axon in a corkscrew-like manner. This is followed subsequently by focal expansion of the corkscrew process to form short cuffs, which then extend longitudinally along the axons. We predict from this model that these spiral cuffs must extend over each other first before extending to form internodes of myelin. Conclusion These experiments show the feasibility of visualizing the dynamics of glial-axonal interaction during myelination over time. Moreover, these approaches complement each other with the in vitro approach allowing visualization of an entire internodal length of myelin and the ex vivo approach validating the in vitro data.
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Affiliation(s)
- Kalliopi Ioannidou
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Kurt I. Anderson
- Institute of Cancer Sciences, The Beatson Institute for Cancer Research, Glasgow, United Kingdom
| | - David Strachan
- Institute of Cancer Sciences, The Beatson Institute for Cancer Research, Glasgow, United Kingdom
| | - Julia M. Edgar
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Susan C. Barnett
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
- * E-mail:
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Ruest T, Holmes WM, Barrie JA, Griffiths IR, Anderson TJ, Dewar D, Edgar JM. High-resolution diffusion tensor imaging of fixed brain in a mouse model of Pelizaeus-Merzbacher disease: comparison with quantitative measures of white matter pathology. NMR Biomed 2011; 24:1369-1379. [PMID: 22223367 DOI: 10.1002/nbm.1700] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 01/25/2011] [Accepted: 01/27/2011] [Indexed: 05/31/2023]
Abstract
Diffusion tensor imaging (DTI) is a powerful technique for the noninvasive assessment of the central nervous system. To facilitate the application of this technique to in vivo studies, we characterised a mouse model of the leukodystrophy, Pelizaeus-Merzbacher disease (PMD), comparing high-resolution ex vivo DTI findings with quantitative histological analysis of selected areas of the brain. The mice used in this study (Plp1-transgenic) carry transgenic copies of the Plp1 gene and are models for PMD as a result of gene duplication. Plp1 transgenic mice display a mild ataxia and experience frequent seizures around the time at which they were imaged. Axial (λ(1) ) and radial (RD) diffusivities and fractional anisotropy (FA) data were analysed using an exploratory whole-brain voxel-based method, a voxel-based approach using tract-based spatial statistics (TBSS), and by application of conventional region of interest (ROI) analyses to selected white matter tracts. Raw t value maps and TBSS analyses indicated widespread changes throughout the brain of Plp1-transgenic mice compared with the wild-type. ROI analyses of the corpus callosum, anterior commissure and hippocampal fimbria showed that FA was reduced significantly, whereas λ(1) and RD were increased significantly, in Plp1-transgenic mice compared with the wild-type. The DTI data derived from ROI analyses were subsequently compared with histological measures taken in the same regions. These revealed an almost complete absence of myelin, preservation of axons, marked astrocytosis and increased or unchanged cell densities. These data contribute to our growing understanding of the basis of anisotropic water diffusion in the normal and diseased nervous system.
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Affiliation(s)
- Torsten Ruest
- Institute of Neuroscience and Psychology and Glasgow Experimental Magnetic Resonance Imaging Centre, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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Karim SA, Barrie JA, McCulloch MC, Montague P, Edgar JM, Iden DL, Anderson TJ, Nave KA, Griffiths IR, McLaughlin M. PLP/DM20 expression and turnover in a transgenic mouse model of Pelizaeus-Merzbacher disease. Glia 2011; 58:1727-38. [PMID: 20629189 DOI: 10.1002/glia.21043] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The most common cause of Pelizaeus-Merzbacher (PMD) is due to duplication of the PLP1 gene but it is unclear how increased gene dosage affects PLP turnover and causes dysmyelination. We have studied the dynamics of PLP/DM20 in a transgenic mouse model of PMD with increased gene dosage of the proteolipid protein gene (Plp1). The turnover of PLP/DM20 were investigated using an ex-vivo brain slice system and cultured oligodendrocytes. Homozygous mice have reduced PLP translation, markedly enhanced PLP degradation, and markedly reduced incorporation of PLP into myelin. Proteasome inhibition (MG132) prevented the enhanced degradation. Numerous autophagic vesicles are present in homozygous transgenic mice that may influence protein dynamics. Surprisingly, promoting autophagy with rapamycin decreases the degradation of nascent PLP suggesting autophagic vacuoles serve as a cellular storage compartment. We suggest that there are multiple subcellular fates of PLP/DM20 when overexpressed: the vast majority being degraded by the proteasome, a proportion sequestered into autophagic vacuoles, probably fused with endolysosomes, and only a small proportion entering the myelin sheath, where its association with lipid rafts is perturbed. Transgenic oligodendrocytes have fewer membrane sheets and this phenotype is improved with siRNA-mediated knockdown of PLP expression that promotes the formation of MBP+ myelin-like sheets. This finding suggests that RNAi technology is in principle applicable to improve CNS myelination when compromised by PLP/DM20 overexpression.
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Affiliation(s)
- Saadia A Karim
- The Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow, G61 1BD, Scotland
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Gruenenfelder FI, Thomson G, Penderis J, Edgar JM. Axon-glial interaction in the CNS: what we have learned from mouse models of Pelizaeus-Merzbacher disease. J Anat 2011; 219:33-43. [PMID: 21401588 DOI: 10.1111/j.1469-7580.2011.01363.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
In the central nervous system (CNS) the majority of axons are surrounded by a myelin sheath, which is produced by oligodendrocytes. Myelin is a lipid-rich insulating material that facilitates the rapid conduction of electrical impulses along the myelinated nerve fibre. Proteolipid protein and its isoform DM20 constitute the most abundant protein component of CNS myelin. Mutations in the PLP1 gene encoding these myelin proteins cause Pelizaeus-Merzbacher disease and the related allelic disorder, spastic paraplegia type 2. Animal models of these diseases, particularly models lacking or overexpressing Plp1, have shed light on the interplay between axons and oligodendrocytes, and how one component influences the other.
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Affiliation(s)
- Fredrik I Gruenenfelder
- Applied Neurobiology Group, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Scotland, UK
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Edgar JM, McCulloch MC, Montague P, Brown AM, Thilemann S, Pratola L, Gruenenfelder FI, Griffiths IR, Nave KA. Demyelination and axonal preservation in a transgenic mouse model of Pelizaeus-Merzbacher disease. EMBO Mol Med 2010; 2:42-50. [PMID: 20091761 PMCID: PMC3377270 DOI: 10.1002/emmm.200900057] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
It is widely thought that demyelination contributes to the degeneration of axons and, in combination with acute inflammatory injury, is responsible for progressive axonal loss and persistent clinical disability in inflammatory demyelinating disease. In this study we sought to characterize the relationship between demyelination, inflammation and axonal transport changes using a Plp1-transgenic mouse model of Pelizaeus-Merzbacher disease. In the optic pathway of this non-immune mediated model of demyelination, myelin loss progresses from the optic nerve head towards the brain, over a period of months. Axonal transport is functionally perturbed at sites associated with local inflammation and ‘damaged’ myelin. Surprisingly, where demyelination is complete, naked axons appear well preserved despite a significant reduction of axonal transport. Our results suggest that neuroinflammation and/or oligodendrocyte dysfunction are more deleterious for axonal health than demyelination per se, at least in the short term.
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Affiliation(s)
- Julia M Edgar
- Institute of Comparative Medicine, University of Glasgow, Scotland, UK.
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Edgar JM, McLaughlin M, Werner HB, McCulloch MC, Barrie JA, Brown A, Faichney AB, Snaidero N, Nave KA, Griffiths IR. Early ultrastructural defects of axons and axon-glia junctions in mice lacking expression of Cnp1. Glia 2010; 57:1815-24. [PMID: 19459211 DOI: 10.1002/glia.20893] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Most axons in the central nervous system (CNS) are surrounded by a multilayered myelin sheath that promotes fast, saltatory conduction of electrical impulses. By insulating the axon, myelin also shields the axoplasm from the extracellular milieu. In the CNS, oligodendrocytes provide support for the long-term maintenance of myelinated axons, independent of the myelin sheath. Here, we use electron microscopy and morphometric analyses to examine the evolution of axonal and oligodendroglial changes in mice deficient in 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP) and in mice deficient in both CNP and proteolipid protein (PLP/DM20). We show that CNP is necessary for the formation of a normal inner tongue process of oligodendrocytes that myelinate small diameter axons. We also show that axonal degeneration in Cnp1 null mice is present very early in postnatal life. Importantly, compact myelin formed by transplanted Cnp1 null oligodendrocytes induces the same degenerative changes in shiverer axons that normally are dysmyelinated but structurally intact. Mice deficient in both CNP and PLP develop a more severe axonal phenotype than either single mutant, indicating that the two oligodendroglial proteins serve distinct functions in supporting the myelinated axon. These observations support a model in which the trophic functions of oligodendrocytes serve to offset the physical shielding of axons by myelin membranes.
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Affiliation(s)
- Julia M Edgar
- Applied Neurobiology Group, Institute of Comparative Medicine, University of Glasgow, Bearsden, Glasgow, Scotland, United Kingdom
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Wang E, Dimova N, Sperle K, Huang Z, Lock L, McCulloch MC, Edgar JM, Hobson GM, Cambi F. Deletion of a splicing enhancer disrupts PLP1/DM20 ratio and myelin stability. Exp Neurol 2008; 214:322-30. [DOI: 10.1016/j.expneurol.2008.09.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2008] [Revised: 08/21/2008] [Accepted: 09/02/2008] [Indexed: 11/30/2022]
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Edgar JM, McCulloch MC, Thomson CE, Griffiths IR. Distribution of mitochondria along small-diameter myelinated central nervous system axons. J Neurosci Res 2008; 86:2250-7. [PMID: 18381760 DOI: 10.1002/jnr.21672] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Small-diameter myelinated CNS axons are preferentially affected in multiple sclerosis (MS) and in the hereditary spastic paraplegias (HSP), in which the distal axon degenerates. Mitochondrial dysfunction has been implicated in the pathogenesis of these and other disorders involving axonal degeneration. The aim of this study was to determine whether the frequency of axonal mitochondria changes along the length of small-diameter fibers and whether there is a preferential localization to the region of the node of Ranvier. We find that mitochondrial numbers do not change along the length of a myelinated small-diameter fiber, and, in contrast to the peripheral nervous system, there is no tendency for mitochondrial numbers to increase at the node.
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Affiliation(s)
- Julia M Edgar
- Applied Neurobiology Group, Institute of Comparative Medicine, University of Glasgow, Bearsden, Glasgow, Scotland.
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Abstract
We showed previously that Theiler's virus, a neurotropic non-enveloped picornavirus of mouse, traffics from the axon of infected neurons into the surrounding myelin. When this traffic is interrupted, as in the shiverer mouse which bears a mutation in the myelin basic protein gene, the virus is unable to persist in the central nervous system. In the present work, we used the Wld(s) mutant mouse, a strain in which axonal degeneration is considerably slowed down, to show that axon to myelin traffic takes place in the absence of axon degeneration. Our results suggest the existence of a mechanism of transfer of axonal cytoplasm into the myelin which Theiler's virus might exploit to ensure its persistence.
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Affiliation(s)
- Jean-Pierre Roussarie
- Department of Virology, URA3015 Centre National de la Recherche Scientifique (CNRS), Institut Pasteur, Paris, France
| | - Claude Ruffié
- Department of Virology, URA3015 Centre National de la Recherche Scientifique (CNRS), Institut Pasteur, Paris, France
| | - Julia M. Edgar
- Applied Neurobiology Group, Institute of Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Ian Griffiths
- Applied Neurobiology Group, Institute of Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Michel Brahic
- Department of Virology, URA3015 Centre National de la Recherche Scientifique (CNRS), Institut Pasteur, Paris, France
- * To whom correspondence should be addressed. E-mail:
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Karim SA, Barrie JA, McCulloch MC, Montague P, Edgar JM, Kirkham D, Anderson TJ, Nave KA, Griffiths IR, McLaughlin M. PLP overexpression perturbs myelin protein composition and myelination in a mouse model of Pelizaeus-Merzbacher disease. Glia 2007; 55:341-51. [PMID: 17133418 DOI: 10.1002/glia.20465] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Duplication of PLP1, an X-linked gene encoding the major myelin membrane protein of the human CNS, is the most frequent cause of Pelizaeus-Merzbacher disease (PMD). Transgenic mice with extra copies of the wild type Plp1 gene, a valid model of PMD, also develop a dysmyelinating phenotype dependant on gene dosage. In this study we have examined the effect of increasing Plp1 gene dosage on levels of PLP/DM20 and on other representative myelin proteins. In cultured oligodendrocytes and early myelinating oligodendrocytes in vivo, increased gene dosage leads to elevated levels of PLP/DM20 in the cell body. During myelination, small increases in Plp1 gene dosage (mice hemizygous for the transgene) elevate the level of PLP/DM20 in oligodendrocyte soma but cause only minimal and transient effects on the protein composition and structure of myelin suggesting that cells can regulate the incorporation of proteins into myelin. However, larger increases in dosage (mice homozygous for the transgene) are not well tolerated, leading to hypomyelination and alteration in the cellular distribution of PLP/DM20. A disproportionate amount of PLP/DM20 is retained in the cell soma, probably in autophagic vacuoles and lysosomes whereas the level in myelin is reduced. Increased Plp1 gene dosage affects other myelin proteins, particularly MBP, which is transitorily reduced in hemizygous mice but consistently and markedly lower in homozygotes in both myelin and naïve or early myelinating oligodendrocytes. Whether the reduced MBP is implicated in the pathogenesis of dysmyelination is yet to be established.
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Affiliation(s)
- Saadia A Karim
- Applied Neurobiology Group, Institute of Comparative Medicine, University of Glasgow, Bearsden, Glasgow, Scotland
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McLaughlin M, Karim SA, Montague P, Barrie JA, Kirkham D, Griffiths IR, Edgar JM. Genetic background influences UPR but not PLP processing in the rumpshaker model of PMD/SPG2. Neurochem Res 2006; 32:167-76. [PMID: 16944321 DOI: 10.1007/s11064-006-9122-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/19/2006] [Indexed: 10/24/2022]
Abstract
Mutations of the proteolipid protein gene (PLP1) cause Pelizaeus-Merzbacher disease (PMD) and Spastic paraplegia type 2 (SPG2). The rumpshaker mutation is associated with mild forms of PMD or SPG2 in man and the identical mutation occurs in mice, the phenotype depending on genetic background. The mild phenotype in C3H mice becomes a lethal disease when expressed on the C57BL/6 background. rumpshaker PLP is synthesised at a similar rate to wild type but is rapidly degraded by the proteasome. We show that the rates of synthesis, degradation and myelin incorporation of PLP/DM20 are similar in mutants on both backgrounds and therefore differences in PLP processing are unlikely to be the basis of the phenotypic variation. An unfolded protein response (UPR) is activated in rumpshaker. Whereas activation of CHOP correlates with phenotypic severity, we find no difference in the response of BiP and X-box protein1 (Xbp1) between the two strains.
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Affiliation(s)
- M McLaughlin
- Applied Neurobiology Group, Division of Cell Sciences, Institute of Comparative Medicine, University of Glasgow, Bearsden, Glasgow, G61 1QH, Scotland
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McLaughlin M, Barrie JA, Karim S, Montague P, Edgar JM, Kirkham D, Thomson CE, Griffiths IR. Processing of PLP in a model of Pelizaeus-Merzbacher disease/SPG2 due to the rumpshaker mutation. Glia 2006; 53:715-22. [PMID: 16506223 DOI: 10.1002/glia.20325] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The rumpshaker mutation of the X-linked myelin proteolipid protein (PLP1) gene causes spastic paraplegia type 2 or a mild form of Pelizaeus-Merzbacher disease in man. The identical mutation occurs spontaneously in mice. Both human and murine diseases are associated with dysmyelination. Using the mouse model, we show that the low steady state levels of PLP result from accelerated proteasomal degradation rather than decreased synthesis. The T(1/2) for degradation of rumpshaker PLP is 11 h compared with 23 h for wild type. A minority of newly synthesized PLP is incorporated into myelin in the correct orientation but at a reduced rate compared with wild type. However, inhibition of proteasomal degradation does not increase the level of PLP incorporated into myelin. As Plp null mice do not have a similar myelin deficiency, it is unlikely that the reduced PLP levels are the main cause of the dysmyelination. Rumpshaker oligodendrocytes also have a reduced level of other myelin proteins, such as MBP, although the mechanisms are not yet defined but are likely to operate at a translational or post-translational level.
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Affiliation(s)
- Mark McLaughlin
- Applied Neurobiology Group, Institute of Comparative Medicine, University of Glasgow, Bearsden Glasgow G61 1QH, Scotland
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Thomson CE, Hunter AM, Griffiths IR, Edgar JM, McCulloch MC. Murine spinal cord explants: A model for evaluating axonal growth and myelination in vitro. J Neurosci Res 2006; 84:1703-15. [PMID: 17075918 DOI: 10.1002/jnr.21084] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In vitro models of myelinating central nervous system axons have mainly been of two types, organotypic or dissociated. In organotypic cultures, the tissue fragment is thick and usually requires sectioning (physically or optically) before visual examination. In dissociated cultures, tissue is dispersed across the culture surface, making it difficult to measure the extent of myelinated fiber growth. We aimed to develop a method of culturing myelinated CNS fibers in defined medium that could be 1) studied by standard immunofluorescence microscopy (i.e., monolayer type culture), 2) used to measure axonal growth, and 3) used to evaluate the effect of substrate and media components on axonal growth and myelination. We used 120-micro m slices of embryonic murine spinal cord as a focal source of CNS tissue from which myelinated axons could extend in a virtual monolayer. Explants were cultured on both poly-L-lysine and astrocytes. The latter were used because they are the scaffold on which axonal growth and myelination occurs during normal development. Outgrowth from the explant and myelination of axons was poor on poly-L-lysine but was promoted by an astrocyte bed layer. The best myelin formation occurred in defined media based on DMEM using N2 mix; it was not promoted by Sato mix or Neurobasal medium with B27 supplement. Neuronal survival was poor in serum-containing medium. This tissue culture model should facilitate the study of factors involved in promoting outgrowth of CNS axons and their myelination. As such it is relevant to studies on myelination and spinal cord repair.
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Affiliation(s)
- Christine E Thomson
- Applied Neurobiology Group, Institute of Comparative Medicine, Division of Cell Sciences, University of Glasgow Veterinary School, Glasgow, Scotland, UK.
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Fowler JH, Edgar JM, Pringle A, McLaughlin M, McCulloch J, Griffiths IR, Garbern JY, Nave KA, Dewar D. α-Amino-3-hydroxy-5-methylisoxazole-4-propionic acid-mediated excitotoxic axonal damage is attenuated in the absence of myelin proteolipid protein. J Neurosci Res 2006; 84:68-77. [PMID: 16625661 DOI: 10.1002/jnr.20859] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
In vivo and in vitro studies have shown that alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)-receptor-mediated excitotoxicity causes cytoskeletal damage to axons. AMPA/kainate receptors are present on oligodendrocytes and myelin, but currently there is no evidence to suggest that axon cylinders contain AMPA receptors. Proteolipid protein (PLP) and DM20 are integral membrane proteins expressed by CNS oligodendrocytes and located in compact myelin. Humans and mice lacking normal PLP/DM20 develop axonal swellings and degeneration, suggesting that local interactions between axons and the oligodendrocyte/myelin unit are important for the normal functioning of axons and that PLP/DM20 is involved in this process. To determine whether perturbed glial-axonal interaction affects AMPA-receptor-mediated axonal damage, AMPA (1.5 nmol) was injected into the caudate nucleus of anesthetized Plp knockout and wild-type male mice (n = 13). Twenty-four hours later, axonal damage was detected by using neurofilament 200 (NF 200) immunohistochemistry and neuronal damage detected via histology. AMPA-induced axonal damage, assessed with NF 200 immunohistochemistry, was significantly reduced in Plp knockout mice compared with wild-type mice (P = 0.015). There was no significant difference in the levels of neuronal perikaryal damage between the Plp knockout and wild-type mice. In addition, there was no significant difference in the levels of glutamate receptor subunits GluR1-4 or KA2 in Plp knockout compared with wild-type littermates. The present study suggests that PLP-mediated interactions among oligodendrocytes, myelin, and axons may be involved in AMPA-mediated axonal damage.
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Affiliation(s)
- J H Fowler
- Division of Clinical Neuroscience, University of Glasgow, Wellcome Surgical Institute, Glasgow G61 1QH, United Kingdom.
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Montague P, McCallion AS, Barrie JE, Edgar JM, McLaughlin M, Davies RW, Griffiths IR. Characterization of the murine splice variantMobp155: Developmental CNS expression pattern and subcellular localization of epitope-tagged protein. Glia 2005; 50:80-5. [PMID: 15625715 DOI: 10.1002/glia.20155] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Members of the myelin-associated oligodendrocytic basic protein (MOBP) family constitute the third most abundant protein in CNS myelin. Although MOBP localizes to the major dense line (MDL) of CNS myelin, the function of the individual isoforms is unknown. Alternative splicing of pre-Mobp mRNA gives rise to six characterized splice variants in both the mouse and the rat. These splice variants share a common N-terminal encoded in Mobp exon 3 comprising 68 amino acids. The predicted protein isoforms differ in their C-termini. Sequence analysis of intron 3 revealed the presence of a putative initiation codon followed by an open reading frame (ORF) encoding 53 amino acids that extends in frame into Mobp exon 4 yielding a predicted MOBP isoform comprising 155 amino acids, designated MOBP155. This newly characterized isoform possessing a novel N-terminus shares a common C-terminus with MOBP170. Mobp170 message is detectable at low abundance throughout myelinogenesis. In contrast, the novel splice variant encoding MOBP155 is expressed at modest levels late in CNS development, coincident with the expression of the abundant splice variant, Mobp81A. Immunostaining of Cos7 cells transiently expressing an epitope-tagged MOBP155 suggested that most of the product was translocated to mitochondria. Although Mobp155 and Mobp170 encode a common predicted C-terminus they have different expression profiles and their products are targeted to mitochondria and the nucleus, respectively, in transiently transfected Cos7 cells.
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Affiliation(s)
- Paul Montague
- Applied Neurobiology Group, Institute of Comparative Medicine, University of Glasgow Veterinary School, Glasgow, Scotland, United Kingdom
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Abstract
The myelin-forming cells, oligodendrocytes and Schwann cells, extend processes that spirally wrap axons and provide the insulation that allows rapid saltatory conduction. Recent data suggest a further role for the myelin-forming cells in axonal support and maintenance. This Mini-Review summarises some of the data that support this view and highlights the molecules involved.
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Affiliation(s)
- J M Edgar
- Applied Neurobiology Group, Institute of Comparative Medicine, University of Glasgow, Bearsden, Glasgow, Scotland.
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Edgar JM, McLaughlin M, Yool D, Zhang SC, Fowler JH, Montague P, Barrie JA, McCulloch MC, Duncan ID, Garbern J, Nave KA, Griffiths IR. Oligodendroglial modulation of fast axonal transport in a mouse model of hereditary spastic paraplegia. ACTA ACUST UNITED AC 2004; 166:121-31. [PMID: 15226307 PMCID: PMC2172145 DOI: 10.1083/jcb.200312012] [Citation(s) in RCA: 230] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Oligodendrocytes are critical for the development of the plasma membrane and cytoskeleton of the axon. In this paper, we show that fast axonal transport is also dependent on the oligodendrocyte. Using a mouse model of hereditary spastic paraplegia type 2 due to a null mutation of the myelin Plp gene, we find a progressive impairment in fast retrograde and anterograde transport. Increased levels of retrograde motor protein subunits are associated with accumulation of membranous organelles distal to nodal complexes. Using cell transplantation, we show categorically that the axonal phenotype is related to the presence of the overlying Plp null myelin. Our data demonstrate a novel role for oligodendrocytes in the local regulation of axonal function and have implications for the axonal loss associated with secondary progressive multiple sclerosis.
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Affiliation(s)
- Julia M Edgar
- Applied Neurobiology Group, Institute of Comparative Medicine, University of Glasgow, Scotland, UK
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Edgar JM, McLaughlin M, Barrie JA, McCulloch MC, Garbern J, Griffiths IR. Age-related axonal and myelin changes in the rumpshaker mutation of the Plp gene. Acta Neuropathol 2004; 107:331-5. [PMID: 14745569 DOI: 10.1007/s00401-003-0808-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2003] [Revised: 11/24/2003] [Accepted: 11/24/2003] [Indexed: 10/26/2022]
Abstract
The PLP1/Plp gene encodes proteolipid protein (PLP) and DM20, the major central nervous system myelin proteins. Mutations in the PLP1/ Plp gene cause dysmyelinating disorders in man and animals. The rumpshaker mutation was first identified in mice and later linked to a family diagnosed with neurological deficits akin to spastic paraplegia. The dysmyelination in the young rumpshaker mouse is well characterised. Here we report evidence for an age-related increase in myelin due mainly to the myelination of small axons, many large axons remain dysmyelinated. Levels of PLP/DM20 and myelin basic protein are considerably greater in myelin fractions from older compared with younger mutants. Myelin in sheaths of larger axons remains poorly compacted and may account for levels of 2',3'-cyclic nucleotide 3'-phosphodiesterase and myelin-associated glycoprotein being elevated over wild type in older mutant mice. A late-onset distal degeneration of the axons of the longest spinal tract, the fasciculus gracilis, is also noted. This is the first report of Wallerian-type degeneration in mice with spontaneous mutations of the Plp gene.
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Affiliation(s)
- J M Edgar
- Applied Neurobiology Group, Department of Veterinary Clinical Studies, Institute of Comparative Medicine, University of Glasgow, Bearsden, G61 1QH, Glasgow, Scotland
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