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Zhang Q, Jiu Y. The regulation of host cytoskeleton during SARS-CoV-2 infection in the nervous system. BRAIN SCIENCE ADVANCES 2023. [DOI: 10.26599/bsa.2023.9050004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023] Open
Abstract
The global economy and public health are currently under enormous pressure since the outbreak of COVID-19. Apart from respiratory discomfort, a subpopulation of COVID-19 patients exhibits neurological symptoms such as headache, myalgia, and loss of smell. Some have even shown encephalitis and necrotizing hemorrhagic encephalopathy. The cytoskeleton of nerve cells changes drastically in these pathologies, indicating that the cytoskeleton and its related proteins are closely related to the pathogenesis of nervous system diseases. In this review, we present the up-to-date association between host cytoskeleton and coronavirus infection in the context of the nervous system. We systematically summarize cytoskeleton-related pathogen-host interactions in both the peripheral and central nervous systems, hoping to contribute to the development of clinical treatment in COVID-19 patients.
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Affiliation(s)
- Qian Zhang
- Unit of Cell Biology and Imaging Study of Pathogen Host Interaction, The Center for Microbes, Development and Health, CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yaming Jiu
- Unit of Cell Biology and Imaging Study of Pathogen Host Interaction, The Center for Microbes, Development and Health, CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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2
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Protocadherin 15 suppresses oligodendrocyte progenitor cell proliferation and promotes motility through distinct signalling pathways. Commun Biol 2022; 5:511. [PMID: 35637313 PMCID: PMC9151716 DOI: 10.1038/s42003-022-03470-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 05/10/2022] [Indexed: 12/15/2022] Open
Abstract
Oligodendrocyte progenitor cells (OPCs) express protocadherin 15 (Pcdh15), a member of the cadherin superfamily of transmembrane proteins. Little is known about the function of Pcdh15 in the central nervous system (CNS), however, Pcdh15 expression can predict glioma aggression and promote the separation of embryonic human OPCs immediately following a cell division. Herein, we show that Pcdh15 knockdown significantly increases extracellular signal-related kinase (ERK) phosphorylation and activation to enhance OPC proliferation in vitro. Furthermore, Pcdh15 knockdown elevates Cdc42-Arp2/3 signalling and impairs actin kinetics, reducing the frequency of lamellipodial extrusion and slowing filopodial withdrawal. Pcdh15 knockdown also reduces the number of processes supported by each OPC and new process generation. Our data indicate that Pcdh15 is a critical regulator of OPC proliferation and process motility, behaviours that characterise the function of these cells in the healthy CNS, and provide mechanistic insight into the role that Pcdh15 might play in glioma progression. Protocadherin 15 promotes lamellipodial and filopodial dynamics in oligodendrocyte progenitor cells by regulating Cdc42-Arp2/3 activity, but also suppresses ERK1/2 phosphorylation to reduce proliferation.
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3
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Carvalho E, Morais M, Ferreira H, Silva M, Guimarães S, Pêgo A. A paradigm shift: Bioengineering meets mechanobiology towards overcoming remyelination failure. Biomaterials 2022; 283:121427. [DOI: 10.1016/j.biomaterials.2022.121427] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 01/31/2022] [Accepted: 02/17/2022] [Indexed: 12/14/2022]
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4
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Lai WF, Wong WT. Roles of the actin cytoskeleton in aging and age-associated diseases. Ageing Res Rev 2020; 58:101021. [PMID: 31968269 DOI: 10.1016/j.arr.2020.101021] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 01/06/2020] [Accepted: 01/17/2020] [Indexed: 12/12/2022]
Abstract
The integrity of the cytoskeleton is essential to diverse cellular processes such as phagocytosis and intracellular trafficking. Disruption of the organization and dynamics of the actin cytoskeleton leads to age-associated symptoms and diseases, ranging from cancer to neurodegeneration. In addition, changes in the integrity of the actin cytoskeleton disrupt the functioning of not only somatic and stem cells but also gametes, resulting in aberrant embryonic development. Strategies to preserve the integrity and dynamics of the cytoskeleton are, therefore, potentially therapeutic to age-related disorders. The objective of this article is to revisit the current understanding of the roles played by the actin cytoskeleton in aging, and to review the opportunities and challenges for the transition of basic research into intervention development. It is hoped that, with the snapshot of evidence regarding changes in actin dynamics with advanced age, insights into future research directions can be attained.
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Affiliation(s)
- Wing-Fu Lai
- School of Pharmaceutical Sciences, Shenzhen University, PR China; School of Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen, PR China; Department of Applied Biology and Chemical Technology, Hong Kong Polytechnic University, Hong Kong Special Administrative Region, PR China.
| | - Wing-Tak Wong
- Department of Applied Biology and Chemical Technology, Hong Kong Polytechnic University, Hong Kong Special Administrative Region, PR China
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5
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Thomason EJ, Escalante M, Osterhout DJ, Fuss B. The oligodendrocyte growth cone and its actin cytoskeleton: A fundamental element for progenitor cell migration and CNS myelination. Glia 2019; 68:1329-1346. [PMID: 31696982 DOI: 10.1002/glia.23735] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 09/26/2019] [Accepted: 10/01/2019] [Indexed: 01/06/2023]
Abstract
Cells of the oligodendrocyte (OLG) lineage engage in highly motile behaviors that are crucial for effective central nervous system (CNS) myelination. These behaviors include the guided migration of OLG progenitor cells (OPCs), the surveying of local environments by cellular processes extending from differentiating and pre-myelinating OLGs, and during the process of active myelin wrapping, the forward movement of the leading edge of the myelin sheath's inner tongue along the axon. Almost all of these motile behaviors are driven by actin cytoskeletal dynamics initiated within a lamellipodial structure that is located at the tip of cellular OLG/OPC processes and is structurally as well as functionally similar to the neuronal growth cone. Accordingly, coordinated stoichiometries of actin filament (F-actin) assembly and disassembly at these OLG/OPC growth cones have been implicated in directing process outgrowth and guidance, and the initiation of myelination. Nonetheless, the functional importance of the OLG/OPC growth cone still remains to be fully understood, and, as a unique aspect of actin cytoskeletal dynamics, F-actin depolymerization and disassembly start to predominate at the transition from myelination initiation to myelin wrapping. This review provides an overview of the current knowledge about OLG/OPC growth cones, and it proposes a model in which actin cytoskeletal dynamics in OLG/OPC growth cones are a main driver for morphological transformations and motile behaviors. Remarkably, these activities, at least at the later stages of OLG maturation, may be regulated independently from the transcriptional gene expression changes typically associated with CNS myelination.
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Affiliation(s)
- Elizabeth J Thomason
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, Virginia
| | - Miguel Escalante
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, Virginia.,Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - Donna J Osterhout
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York
| | - Babette Fuss
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, Virginia
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6
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Seixas AI, Azevedo MM, Paes de Faria J, Fernandes D, Mendes Pinto I, Relvas JB. Evolvability of the actin cytoskeleton in oligodendrocytes during central nervous system development and aging. Cell Mol Life Sci 2019; 76:1-11. [PMID: 30302529 PMCID: PMC11105620 DOI: 10.1007/s00018-018-2915-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 08/24/2018] [Accepted: 09/04/2018] [Indexed: 01/23/2023]
Abstract
The organization of actin filaments into a wide range of subcellular structures is a defining feature of cell shape and dynamics, important for tissue development and homeostasis. Nervous system function requires morphological and functional plasticity of neurons and glial cells, which is largely determined by the dynamic reorganization of the actin cytoskeleton in response to intrinsic and extracellular signals. Oligodendrocytes are specialized glia that extend multiple actin-based protrusions to form the multilayered myelin membrane that spirally wraps around axons, increasing conduction speed and promoting long-term axonal integrity. Myelination is a remarkable biological paradigm in development, and maintenance of myelin is essential for a healthy adult nervous system. In this review, we discuss how structure and dynamics of the actin cytoskeleton is a defining feature of myelinating oligodendrocytes' biology and function. We also review "old and new" concepts to reflect on the potential role of the cytoskeleton in balancing life and death of myelin membranes and oligodendrocytes in the aging central nervous system.
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Affiliation(s)
- Ana Isabel Seixas
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal.
- IBMC - Instituto de Biologia Molecular e Celular, Porto, Portugal.
| | - Maria Manuela Azevedo
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal
- IBMC - Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Joana Paes de Faria
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal
- IBMC - Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Diogo Fernandes
- Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- International Iberian Nanotechnology Laboratory - INL, Braga, Portugal
| | - Inês Mendes Pinto
- International Iberian Nanotechnology Laboratory - INL, Braga, Portugal
| | - João Bettencourt Relvas
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal
- IBMC - Instituto de Biologia Molecular e Celular, Porto, Portugal
- The Discoveries Centre for Regeneration and Precision Medicine, Porto Campus, Porto, Portugal
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Azevedo MM, Domingues HS, Cordelières FP, Sampaio P, Seixas AI, Relvas JB. Jmy regulates oligodendrocyte differentiation via modulation of actin cytoskeleton dynamics. Glia 2018; 66:1826-1844. [DOI: 10.1002/glia.23342] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 03/26/2018] [Accepted: 04/05/2018] [Indexed: 12/11/2022]
Affiliation(s)
- Maria M. Azevedo
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto; Porto Portugal
- IBMC - Instituto de Biologia Molecular e Celular; Porto Portugal
| | - Helena S. Domingues
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto; Porto Portugal
- IBMC - Instituto de Biologia Molecular e Celular; Porto Portugal
| | - Fabrice P. Cordelières
- Bordeaux Imaging Centre, UMS 3420 CNRS, CNRS-INSERM, University of Bordeaux; Bordeaux France
| | - Paula Sampaio
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto; Porto Portugal
- IBMC - Instituto de Biologia Molecular e Celular; Porto Portugal
| | - Ana I. Seixas
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto; Porto Portugal
- IBMC - Instituto de Biologia Molecular e Celular; Porto Portugal
| | - João B. Relvas
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto; Porto Portugal
- IBMC - Instituto de Biologia Molecular e Celular; Porto Portugal
- The Discoveries Centre for Regeneration and Precision Medicine, Porto campus; Porto Portugal
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Collar occupancy: A new quantitative imaging tool for morphometric analysis of oligodendrocytes. J Neurosci Methods 2017; 294:122-135. [PMID: 29174019 DOI: 10.1016/j.jneumeth.2017.11.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 11/17/2017] [Accepted: 11/19/2017] [Indexed: 12/14/2022]
Abstract
BACKGROUND Oligodendrocytes (OL) are the myelinating cells of the central nervous system. OL differentiation from oligodendrocyte progenitor cells (OPC) is accompanied by characteristic stereotypical morphological changes. Quantitative imaging of those morphological alterations during OPC differentiation is commonly used for characterization of new molecules in cell differentiation and myelination and screening of new pro-myelinating drugs. Current available imaging analysis methods imply a non-automated morphology assessment, which is time-consuming and prone to user subjective evaluation. NEW METHOD Here, we describe an automated high-throughput quantitative image analysis method entitled collar occupancy that allows morphometric ranking of different stages of in vitro OL differentiation in a high-content analysis format. Collar occupancy is based on the determination of the percentage of area occupied by OPC/OL cytoplasmic protrusions within a defined region that contains the protrusion network, the collar. RESULTS We observed that more differentiated cells have higher collar occupancy and, therefore, this parameter correlates with the degree of OL differentiation. COMPARISON WITH EXISTING METHODS In comparison with the method of manual categorization, we found the collar occupancy to be more robust and unbiased. Moreover, when coupled with myelin basic protein (MBP) staining to quantify the percentage of myelinating cells, we were able to evaluate the role of new molecules in OL differentiation and myelination, such as Dusp19 and Kank2. CONCLUSIONS Altogether, we have successfully developed an automated and quantitative method to morphologically characterize OL differentiation in vitro that can be used in multiple studies of OL biology.
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On Myelinated Axon Plasticity and Neuronal Circuit Formation and Function. J Neurosci 2017; 37:10023-10034. [PMID: 29046438 DOI: 10.1523/jneurosci.3185-16.2017] [Citation(s) in RCA: 128] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Revised: 08/31/2017] [Indexed: 12/28/2022] Open
Abstract
Studies of activity-driven nervous system plasticity have primarily focused on the gray matter. However, MRI-based imaging studies have shown that white matter, primarily composed of myelinated axons, can also be dynamically regulated by activity of the healthy brain. Myelination in the CNS is an ongoing process that starts around birth and continues throughout life. Myelin in the CNS is generated by oligodendrocytes and recent evidence has shown that many aspects of oligodendrocyte development and myelination can be modulated by extrinsic signals including neuronal activity. Because modulation of myelin can, in turn, affect several aspects of conduction, the concept has emerged that activity-regulated myelination represents an important form of nervous system plasticity. Here we review our increasing understanding of how neuronal activity regulates oligodendrocytes and myelinated axons in vivo, with a focus on the timing of relevant processes. We highlight the observations that neuronal activity can rapidly tune axonal diameter, promote re-entry of oligodendrocyte progenitor cells into the cell cycle, or drive their direct differentiation into oligodendrocytes. We suggest that activity-regulated myelin formation and remodeling that significantly change axonal conduction properties are most likely to occur over timescales of days to weeks. Finally, we propose that precise fine-tuning of conduction along already-myelinated axons may also be mediated by alterations to the axon itself. We conclude that future studies need to analyze activity-driven adaptations to both axons and their myelin sheaths to fully understand how myelinated axon plasticity contributes to neuronal circuit formation and function.
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10
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Domingues HS, Cruz A, Chan JR, Relvas JB, Rubinstein B, Pinto IM. Mechanical plasticity during oligodendrocyte differentiation and myelination. Glia 2017; 66:5-14. [PMID: 28940651 DOI: 10.1002/glia.23206] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 07/31/2017] [Accepted: 08/01/2017] [Indexed: 12/14/2022]
Abstract
In the central nervous system, oligodendrocyte precursor cells are exclusive in their potential to differentiate into myelinating oligodendrocytes. Oligodendrocyte precursor cells migrate within the parenchyma and extend cell membrane protrusions that ultimately evolve into myelinating sheaths able to wrap neuronal axons and significantly increase their electrical conductivity. The subcellular force generating mechanisms driving morphological and functional transformations during oligodendrocyte differentiation and myelination remain elusive. In this review, we highlight the mechanical processes governing oligodendrocyte plasticity in a dynamic interaction with the extracellular matrix.
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Affiliation(s)
| | - Andrea Cruz
- International Iberian Nanotechnology Laboratory - INL, Braga, Portugal
| | - Jonah R Chan
- Department of Neurology, University of California, San Francisco, United States of America
| | - João B Relvas
- Instituto de Biologia Molecular e Celular - IBMC, Universidade do Porto, Porto, Portugal.,Instituto de Investigação e Inovação em Saúde - I3S, Universidade do Porto, Porto, Portugal
| | - Boris Rubinstein
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Inês Mendes Pinto
- International Iberian Nanotechnology Laboratory - INL, Braga, Portugal
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11
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Almeida R, Lyons D. Oligodendrocyte Development in the Absence of Their Target Axons In Vivo. PLoS One 2016; 11:e0164432. [PMID: 27716830 PMCID: PMC5055324 DOI: 10.1371/journal.pone.0164432] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 09/26/2016] [Indexed: 11/19/2022] Open
Abstract
Oligodendrocytes form myelin around axons of the central nervous system, enabling saltatory conduction. Recent work has established that axons can regulate certain aspects of oligodendrocyte development and myelination, yet remarkably oligodendrocytes in culture retain the ability to differentiate in the absence of axons and elaborate myelin sheaths around synthetic axon-like substrates. It remains unclear the extent to which the life-course of oligodendrocytes requires the presence of, or signals derived from axons in vivo. In particular, it is unclear whether the specific axons fated for myelination regulate the oligodendrocyte population in a living organism, and if so, which precise steps of oligodendrocyte-cell lineage progression are regulated by target axons. Here, we use live-imaging of zebrafish larvae carrying transgenic reporters that label oligodendrocyte-lineage cells to investigate which aspects of oligodendrocyte development, from specification to differentiation, are affected when we manipulate the target axonal environment. To drastically reduce the number of axons targeted for myelination, we use a previously identified kinesin-binding protein (kbp) mutant, in which the first myelinated axons in the spinal cord, reticulospinal axons, do not fully grow in length, creating a region in the posterior spinal cord where most initial targets for myelination are absent. We find that a 73% reduction of reticulospinal axon surface in the posterior spinal cord of kbp mutants results in a 27% reduction in the number of oligodendrocytes. By time-lapse analysis of transgenic OPC reporters, we find that the reduction in oligodendrocyte number is explained by a reduction in OPC proliferation and survival. Interestingly, OPC specification and migration are unaltered in the near absence of normal axonal targets. Finally, we find that timely differentiation of OPCs into oligodendrocytes does not depend at all on the presence of target axons. Together, our data illustrate the power of zebrafish for studying the entire life-course of the oligodendrocyte lineage in vivo in an altered axonal environment.
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Affiliation(s)
- Rafael Almeida
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom
- MS Society Centre for Translational Research, University of Edinburgh, Edinburgh, United Kingdom
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail: (RA); (DL)
| | - David Lyons
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom
- MS Society Centre for Translational Research, University of Edinburgh, Edinburgh, United Kingdom
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail: (RA); (DL)
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Yang ML, Shin J, Kearns CA, Langworthy MM, Snell H, Walker MB, Appel B. CNS myelination requires cytoplasmic dynein function. Dev Dyn 2015; 244:134-45. [PMID: 25488883 DOI: 10.1002/dvdy.24238] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 11/26/2014] [Accepted: 12/03/2014] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Cytoplasmic dynein provides the main motor force for minus-end-directed transport of cargo on microtubules. Within the vertebrate central nervous system (CNS), proliferation, neuronal migration, and retrograde axon transport are among the cellular functions known to require dynein. Accordingly, mutations of DYNC1H1, which encodes the heavy chain subunit of cytoplasmic dynein, have been linked to developmental brain malformations and axonal pathologies. Oligodendrocytes, the myelinating glial cell type of the CNS, migrate from their origins to their target axons and subsequently extend multiple long processes that ensheath axons with specialized insulating membrane. These processes are filled with microtubules, which facilitate molecular transport of myelin components. However, whether oligodendrocytes require cytoplasmic dynein to ensheath axons with myelin is not known. RESULTS We identified a mutation of zebrafish dync1h1 in a forward genetic screen that caused a deficit of oligodendrocytes. Using in vivo imaging and gene expression analyses, we additionally found evidence that dync1h1 promotes axon ensheathment and myelin gene expression. CONCLUSIONS In addition to its well known roles in axon transport and neuronal migration, cytoplasmic dynein contributes to neural development by promoting myelination.
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Abstract
CNS myelination and the maturation of the myelinating cells of the CNS, namely oligodendrocytes, are thought to be regulated by molecular mechanisms controlling the actin cytoskeleton. However, the exact nature of these mechanisms is currently only poorly understood. Here we assessed the role of calcium/calmodulin-dependent kinase type II (CaMKII), in particular CaMKIIβ, in oligodendrocyte maturation and CNS myelination. Using in vitro culture studies, our data demonstrate that CaMKIIβ is critical for the proper morphological maturation of differentiating oligodendrocytes, an aspect of oligodendrocyte maturation that is mediated to a large extent by changes in the cellular cytoskeleton. Furthermore, our data provide evidence for an actin-cytoskeleton-stabilizing role of CaMKIIβ in differentiating oligodendrocytes. Using Camk2b knock-out and Camk2b(A303R) mutant mice, our data revealed an in vivo functional role of CaMKIIβ in regulating myelin thickness that may be mediated by a non-kinase-catalytic activity. Our data point toward a critical role of CaMKIIβ in regulating oligodendrocyte maturation and CNS myelination via an actin-cytoskeleton-regulatory mechanism.
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Wang H, Rusielewicz T, Tewari A, Leitman EM, Einheber S, Melendez-Vasquez CV. Myosin II is a negative regulator of oligodendrocyte morphological differentiation. J Neurosci Res 2012; 90:1547-56. [PMID: 22437915 DOI: 10.1002/jnr.23036] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 12/20/2011] [Accepted: 12/28/2011] [Indexed: 02/01/2023]
Abstract
During their development as myelinating cells, oligodendrocyte progenitors (OPC) undergo dramatic changes in the organization of their cytoskeleton. These changes involve an increase in cell branching and in lamella extension, which is important for the ability of oligodendrocytes to myelinate multiple axons in the CNS. We have previously shown that the levels of the actin-associated motor protein nonmuscle myosin II (NMII) decrease as oligodendrocyte differentiate and that inhibition of NMII activity increases branching and myelination, suggesting that NMII is a negative regulator of oligodendrocyte differentiation. In agreement with this interpretation, we have found that overexpression of NMII prevents oligodendrocyte branching and differentiation and that OPC maturation is accelerated in NMII knockout mice as shown by a significant increase in the percentage of mature MBP(+) cells. Although several pathways have been implicated in oligodendrocyte morphogenesis, their specific contribution to the regulation of NMII activity has not been directly examined. We tested the hypothesis that the activity of NMII in OPC is controlled by Fyn kinase via downregulation of RhoA-ROCK-NMII phosphorylation. We found that treatment with PP2 or knockdown of Fyn using siRNA prevents the decrease in myosin phosphorylation normally observed during OPC differentiation and that the inhibition of branching induced by overexpression of constitutively active RhoA can be reversed by treatment with Y27632 or blebbistatin. Taken together, our results demonstrate that Fyn kinase downregulates NMII activity, thus promoting oligodendrocyte morphological differentiation.
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Affiliation(s)
- Haibo Wang
- Department of Biological Sciences, Hunter College, City University of New York, New York, New York 10065, USA
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15
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Lack of adrenomedullin affects growth and differentiation of adult neural stem/progenitor cells. Cell Tissue Res 2010; 340:1-11. [PMID: 20182890 DOI: 10.1007/s00441-010-0934-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Accepted: 01/20/2010] [Indexed: 10/19/2022]
Abstract
Adrenomedullin (AM) is a peptide hormone involved in the modulation of cellular growth, migration, apoptosis, and angiogenesis. These characteristics suggest that AM is involved in the control of neural stem/progenitor cell (NSPC) biology. To explore this hypothesis, we have obtained NSPC from the olfactory bulb of adult wild-type animals and brain conditional knockouts for adm, the gene that produces AM. Knockout NSPC contain higher levels of hyperpolymerized tubulin and more abundant filopodia than adm-containing cells, resulting in a different morphology in culture, whereas the size of the knockout neurospheres is smaller than that of the wild-types. Proliferation studies have demonstrated that adm-null NSPC incorporate less 5'-bromodeoxyuridine (BrdU) than their wild-type counterparts. In contrast, BrdU studies in the olfactory bulb of adult animals show more labeled cells in adm-null mice that in wild-types, suggesting that a compensatory mechanism exists that guarantees the sufficient production of neural cells in this organ. In NSPC differentiation tests, lack of adm results in significantly lower proportions of neurons and astrocytes and higher proportions of oligodendrocytes. The oligodendrocytes produced from adm-null neurospheres present an immature phenotype with fewer and shorter processes than adm-containing oligodendrocytes. Thus, AM is an important factor in regulating the proliferation and differentiation of adult NSPC and might be used to modulate stem cell renewal and fate in protocols destined to produce neural cells for regenerative therapies.
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16
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Haber M, Vautrin S, Fry EJ, Murai KK. Subtype-specific oligodendrocyte dynamics in organotypic culture. Glia 2009; 57:1000-13. [DOI: 10.1002/glia.20824] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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17
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Gordon D, Kidd GJ, Smith R. Antisense suppression of tau in cultured rat oligodendrocytes inhibits process formation. J Neurosci Res 2009; 86:2591-601. [PMID: 18500753 DOI: 10.1002/jnr.21719] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The microtubule-associated protein tau is integral to neuronal process development and has a role in the pathogenesis of several neurodegenerative conditions. We examined possible roles for tau in cultured oligodendrocyte process formation by using antisense oligonucleotide treatment. Inhibition of tau synthesis with single oligonucleotides resulted in decreased tau protein levels and significantly shorter cellular processes. Simultaneous use of two nonoverlapping oligonucleotides caused a major reduction in tau levels and severely inhibited process outgrowth. The timing of oligonucleotide addition to oligodendrocyte cultures was important, with addition of antisense at the time of plating into culture having the most significant effect on morphology through reduction of tau expression.
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Affiliation(s)
- David Gordon
- Department of Biochemistry and Molecular Biology, The University of Queensland, Brisbane, Queensland, Australia.
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18
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Wang H, Tewari A, Einheber S, Salzer JL, Melendez-Vasquez CV. Myosin II has distinct functions in PNS and CNS myelin sheath formation. ACTA ACUST UNITED AC 2008; 182:1171-84. [PMID: 18794332 PMCID: PMC2542477 DOI: 10.1083/jcb.200802091] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The myelin sheath forms by the spiral wrapping of a glial membrane around the axon. The mechanisms responsible for this process are unknown but are likely to involve coordinated changes in the glial cell cytoskeleton. We have found that inhibition of myosin II, a key regulator of actin cytoskeleton dynamics, has remarkably opposite effects on myelin formation by Schwann cells (SC) and oligodendrocytes (OL). Myosin II is necessary for initial interactions between SC and axons, and its inhibition or down-regulation impairs their ability to segregate axons and elongate along them, preventing the formation of a 1:1 relationship, which is critical for peripheral nervous system myelination. In contrast, OL branching, differentiation, and myelin formation are potentiated by inhibition of myosin II. Thus, by controlling the spatial and localized activation of actin polymerization, myosin II regulates SC polarization and OL branching, and by extension their ability to form myelin. Our data indicate that the mechanisms regulating myelination in the peripheral and central nervous systems are distinct.
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Affiliation(s)
- Haibo Wang
- Department of Biological Sciences, Hunter College, City University of New York, New York, NY 10065, USA
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Nogaroli L, Yuelling LM, Dennis J, Gorse K, Payne SG, Fuss B. Lysophosphatidic acid can support the formation of membranous structures and an increase in MBP mRNA levels in differentiating oligodendrocytes. Neurochem Res 2008; 34:182-93. [PMID: 18594965 DOI: 10.1007/s11064-008-9772-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Accepted: 06/03/2008] [Indexed: 11/29/2022]
Abstract
During development, differentiating oligodendrocytes progress in distinct maturation steps from premyelinating to myelinating cells. Such maturing oligodendrocytes express both the receptors mediating signaling via extracellular lysophosphatidic acid (LPA) and the major enzyme generating extracellular LPA, namely phosphodiesterase-Ialpha/autotaxin (PD-Ialpha/ATX). However, the biological role of extracellular LPA during the maturation of differentiating oligodendrocytes is currently unclear. Here, we demonstrate that application of exogenous LPA induced an increase in the area occupied by the oligodendrocytes' process network, but only when PD-Ialpha/ATX expression was down-regulated. This increase in network area was caused primarily by the formation of membranous structures. In addition, LPA increased the number of cells positive for myelin basic protein (MBP). This effect was associated by an increase in the mRNA levels coding for MBP but not myelin oligodendrocyte glycoprotein (MOG). Taken together, these data suggest that LPA may play a crucial role in regulating the later stages of oligodendrocyte maturation.
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Affiliation(s)
- Luciana Nogaroli
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, PO Box 980709, Richmond, VA 23298, USA
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20
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Dennis J, White MA, Forrest AD, Yuelling LM, Nogaroli L, Afshari FS, Fox MA, Fuss B. Phosphodiesterase-Ialpha/autotaxin's MORFO domain regulates oligodendroglial process network formation and focal adhesion organization. Mol Cell Neurosci 2007; 37:412-24. [PMID: 18164210 DOI: 10.1016/j.mcn.2007.10.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Revised: 10/23/2007] [Accepted: 10/30/2007] [Indexed: 10/22/2022] Open
Abstract
Development of a complex process network by maturing oligodendrocytes is a critical but currently poorly characterized step toward myelination. Here, we demonstrate that the matricellular oligodendrocyte-derived protein phosphodiesterase-Ialpha/autotaxin (PD-Ialpha/ATX) and especially its MORFO domain are able to promote this developmental step. In particular, the single EF hand-like motif located within PD-Ialpha/ATX's MORFO domain was found to stimulate the outgrowth of higher order branches but not process elongation. This motif was also observed to be critical for the stimulatory effect of PD-Ialpha/ATX's MORFO domain on the reorganization of focal adhesions located at the leading edge of oligodendroglial protrusions. Collectively, our data suggest that PD-Ialpha/ATX promotes oligodendroglial process network formation and expansion via the cooperative action of multiple functional sites located within the MORFO domain and more specifically, a novel signaling pathway mediated by the single EF hand-like motif and regulating the correlated events of process outgrowth and focal adhesion organization.
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Affiliation(s)
- Jameel Dennis
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA
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21
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Abstract
A product of myosin Va mutations, Griscelli's syndrome type 1 (GS1) is characterized by several neurologic deficits including quadraparesis, mental retardation, and seizures. Although multiple studies have not clearly established a cause for the neurologic deficits linked with GS1, a few reports suggest that GS1 is associated with abnormal myelination, which could cause the neurologic deficits seen with GS1. In this report, we investigate whether myosin Va is critical to oligodendrocyte morphology and to myelination in vivo. We found that myosin Va-null mice exhibit significantly impaired myelination of the brain, optic nerve, and spinal cord. Oligodendrocytes express myosin Va and loss of myosin Va function resulted in significantly smaller lamellas and decreased process number, length, and branching of oligodendrocytes. Loss of myosin Va function also blocked distal localization of vesicle-associated membrane protein 2 (VAMP2), which is known to associate with myosin Va. When VAMP2 function was disrupted, oligodendrocytes exhibited similar morphologic deficits to what is seen with functional ablation of myosin Va. Our findings establish a role for both myosin Va and VAMP2 in oligodendrocyte function as it relates to myelination.
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Nielsen JA, Maric D, Lau P, Barker JL, Hudson LD. Identification of a novel oligodendrocyte cell adhesion protein using gene expression profiling. J Neurosci 2006; 26:9881-91. [PMID: 17005852 PMCID: PMC1613258 DOI: 10.1523/jneurosci.2246-06.2006] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Oligodendrocytes undergo extensive changes as they differentiate from progenitors into myelinating cells. To better understand the molecular mechanisms underlying this transformation, we performed a comparative analysis using gene expression profiling of A2B5+ oligodendrocyte progenitors and O4+ oligodendrocytes. Cells were sort-purified ex vivo from postnatal rat brain using flow cytometry. Using Affymetrix microarrays, 1707 transcripts were identified with a more than twofold increase in expression in O4+ oligodendrocytes. Many genes required for oligodendrocyte differentiation were upregulated in O4+ oligodendrocytes, including numerous genes encoding myelin proteins. Transcriptional changes included genes required for cell adhesion, actin cytoskeleton regulation, and fatty acid and cholesterol biosynthesis. At the O4+ stage, there was an increase in expression of a novel proline-rich transmembrane protein (Prmp). Localized to the plasma membrane, Prmp displays adhesive properties that may be important for linking the extracellular matrix to the actin cytoskeleton. Together, our results highlight the usefulness of this discovery-driven experimental strategy to identify genes relevant to oligodendrocyte differentiation and myelination.
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Affiliation(s)
| | - Dragan Maric
- Laboratory of Neurophysiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892
| | | | - Jeffery L. Barker
- Laboratory of Neurophysiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892
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Kirby BB, Takada N, Latimer AJ, Shin J, Carney TJ, Kelsh RN, Appel B. In vivo time-lapse imaging shows dynamic oligodendrocyte progenitor behavior during zebrafish development. Nat Neurosci 2006; 9:1506-11. [PMID: 17099706 DOI: 10.1038/nn1803] [Citation(s) in RCA: 298] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2006] [Accepted: 10/24/2006] [Indexed: 01/31/2023]
Abstract
Myelinating oligodendrocytes arise from migratory and proliferative oligodendrocyte progenitor cells (OPCs). Complete myelination requires that oligodendrocytes be uniformly distributed and form numerous, periodically spaced membrane sheaths along the entire length of target axons. Mechanisms that determine spacing of oligodendrocytes and their myelinating processes are not known. Using in vivo time-lapse confocal microscopy, we show that zebrafish OPCs continuously extend and retract numerous filopodium-like processes as they migrate and settle into their final positions. Process remodeling and migration paths are highly variable and seem to be influenced by contact with neighboring OPCs. After laser ablation of oligodendrocyte-lineage cells, nearby OPCs divide more frequently, orient processes toward the ablated cells and migrate to fill the unoccupied space. Thus, process activity before axon wrapping might serve as a surveillance mechanism by which OPCs determine the presence or absence of nearby oligodendrocyte-lineage cells, facilitating uniform spacing of oligodendrocytes and complete myelination.
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Affiliation(s)
- Brandon B Kirby
- Department of Biological Sciences, Vanderbilt University, 465 21st Avenue South, Nashville, Tennessee 37232, USA
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Fox MA, Afshari FS, Alexander JK, Colello RJ, Fuss B. Growth conelike sensorimotor structures are characteristic features of postmigratory, premyelinating oligodendrocytes. Glia 2006; 53:563-6. [PMID: 16355369 DOI: 10.1002/glia.20293] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
During development, postmigratory, premyelinating oligodendrocytes extend processes that navigate through the central nervous system (CNS) environment, where they recognize a number of extracellular cues, including axonal segments to be myelinated. Ultimately this recognition event leads to the formation of the CNS myelin sheath. However, the morphological structures and molecular mechanisms that control such oligodendroglial pathfinding are poorly understood. Here we show that postmigratory, premyelinating oligodendrocyte processes possess at their distal tips expansions that ultrastructurally resemble growth cones of postmigratory neurons and that we will refer to as OLG-growth cones. OLG-growth cones are highly motile and capable of mediating process outgrowth, retraction, and branching. In addition, they express regulators of cytoskeletal organization, GAP43 and cofilin, that are known to mediate neuronal growth cone navigation. In a choice situation, processes of postmigratory, premyelinating oligodendrocytes and their OLG-growth cones have the ability to selectively avoid a nonpermissive substrate, that is, collagen IV. Thus, our findings provide, for the first time, a detailed characterization of sensorimotor structures present at the tips of postmigratory, premyelinating oligodendrocyte processes. Furthermore, the data presented here suggest that, although the cellular mechanisms involved in growth cone steering may be similar for postmigratory neuronal and oligodendroglial cells, extracellular cues may be interpreted in a cell-type-specific fashion.
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Affiliation(s)
- Michael A Fox
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298, USA
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25
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Vasenkova I, Luginbuhl D, Chiba A. Gliopodia extend the range of direct glia-neuron communication during the CNS development in Drosophila. Mol Cell Neurosci 2005; 31:123-30. [PMID: 16298140 DOI: 10.1016/j.mcn.2005.10.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2005] [Revised: 09/16/2005] [Accepted: 10/04/2005] [Indexed: 11/20/2022] Open
Abstract
Midline glia are a source of cues for neuronal navigation and differentiation in the Drosophila CNS. Despite their importance, how glia and neurons communicate during the development is not fully understood. Here, we examined dynamic morphology of midline glia and assessed their direct cellular interactions with neurons within the embryonic CNS. Midline glia extend filopodia-like "gliopodia" from the onset of axogenesis through the near completion of embryonic neural development. The most abundant and stable within the commissures, gliopodia frequently contact neurites extending from the neuropil on either side of the midline. Misexpression of Rac1N17 in midline glia not only reduces the number of gliopodia but also shifts the position of neuropils towards the midline. Midline-secreted signaling protein Slit accumulates along the surface of gliopodia. Mutant analysis supports the idea that gliopodia contribute to its presentation on neuronal surfaces at both the commissures and neuropils. We propose that gliopodia extend the range of direct glia-neuron communication during CNS development.
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Affiliation(s)
- Irina Vasenkova
- Department of Cell and Developmental Biology, University of Illinois, 601 South Goodwin Avenue, Urbana, IL 61801, USA
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26
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Terada N, Kidd GJ, Kinter M, Bjartmar C, Moran-Jones K, Trapp BD. Beta IV tubulin is selectively expressed by oligodendrocytes in the central nervous system. Glia 2005; 50:212-22. [PMID: 15712210 DOI: 10.1002/glia.20175] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Oligodendrocyte differentiation and myelination involve dramatic changes in cell signaling pathways, gene expression patterns, cell shape, and cytoskeletal organization. In a pilot study investigating CNS angiogenesis, oligodendrocytes were intensely labeled by antisera directed against the C-terminal of Tie-2, a 140-kDa transmembrane receptor for angiopoietin. Immunoprecipitation of rat brain proteins with Tie-2 C-terminal antisera, however, produced a single spot of approximately 55-kDa pI approximately 5 by two-dimensional (2D) electrophoresis, which was identified as beta-tubulin by mass spectrometry. Isotype-specific antibodies for beta(IV) tubulin selectively labeled oligodendrocytes. First detected in premyelinating oligodendrocytes, beta(IV) tubulin was abundant in myelinating oligodendrocyte perinuclear cytoplasm and processes extending to and along developing myelin internodes. Beta(IV) tubulin-positive MTs were diffusely distributed in oligodendrocyte perinuclear cytoplasm and not organized around the centrosome. Beta(IV) tubulin may play a role in establishing the oligodendrocyte MT network, which is essential for the transport of myelin proteins, lipids, and RNA during myelination.
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Affiliation(s)
- Nobuo Terada
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
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27
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Melendez-Vasquez CV, Einheber S, Salzer JL. Rho kinase regulates schwann cell myelination and formation of associated axonal domains. J Neurosci 2004; 24:3953-63. [PMID: 15102911 PMCID: PMC6729425 DOI: 10.1523/jneurosci.4920-03.2004] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The myelin sheath forms by the spiral wrapping of a glial membrane around an axon. The mechanisms involved are poorly understood but are likely to involve coordinated changes in the glial cell cytoskeleton. Because of its key role as a regulator of the cytoskeleton, we investigated the role of Rho kinase (ROCK), a major downstream effector of Rho, in Schwann cell morphology, differentiation, and myelination. Pharmacologic inhibition of ROCK activity results in loss of microvilli and stress fibers in Schwann cell cultures and strikingly aberrant myelination in Schwann cell-neuron cocultures; there was no effect on Schwann cell proliferation or differentiation. Treated Schwann cells branch aberrantly and form multiple, small, independent myelin segments along the length of axons, each with associated nodes and paranodes. This organization partially resembles myelin formed by oligodendrocytes rather than the single long myelin sheath characteristic of Schwann cells. ROCK regulates myosin light chain phosphorylation, which is robustly, but transiently, activated at the onset of myelination. These results support a key role of Rho through its effector ROCK in coordinating the movement of the glial membrane around the axon at the onset of myelination via regulation of myosin phosphorylation and actomyosin assembly. They also indicate that the molecular machinery that promotes the wrapping of the glial membrane sheath around the axon is distributed along the entire length of the internode.
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Affiliation(s)
- Carmen V Melendez-Vasquez
- Department of Cell Biology, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, New York 10016, USA.
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28
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Song J, Carson JH, Barbarese E, Li FY, Duncan ID. RNA transport in oligodendrocytes from the taiep mutant rat. Mol Cell Neurosci 2003; 24:926-38. [PMID: 14697659 DOI: 10.1016/s1044-7431(03)00254-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The results presented here identify a new RNA trafficking phenotype in taiep oligodendrocytes that increases the frequency of reversals and restricts the extent of transport of RNA containing the A2RE transport signal from MBP mRNA. The taiep rat is a myelin mutant characterized by excessive accumulation of microtubules in oligodendrocytes and myelin deficiency in the central nervous system. The taiep RNA trafficking is developmentally correlated with the microtubule accumulation in oligodendrocytes and can be partially suppressed by reducing microtubule density with nocodazole or inhibiting dynein activity by coinjecting anti-dynein antibodies. These results suggest that RNA trafficking in taiep oligodendrocytes is inhibited by enhanced dynein activity that neutralizes or lessens the normal overriding power of the plus-end directed motor kinesin. Altered orientation of microtubules in oligodendrocyte fine processes and a physical barrier created by densely packed microtubules may also contribute to the inhibition of RNA trafficking in taiep oligodendrocytes.
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Affiliation(s)
- Jonathan Song
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706, USA.
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29
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Rumsby M, Afsari F, Stark M, Hughson E. Microfilament and microtubule organization and dynamics in process extension by central glia-4 oligodendrocytes: evidence for a microtubule organizing center. Glia 2003; 42:118-29. [PMID: 12655596 DOI: 10.1002/glia.10211] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Microfilaments in freshly adhering CG-4 cells and differentiated CG-4 oligodendrocytes are concentrated at the tips and edges of rapidly forming processes while microtubules are concentrated in new processes and extend from a concentrated spot of alpha-tubulin staining in the cell body to the cell periphery. In motile bipolar CG-4 cells, microfilaments are heavily concentrated at the flattened end of one process and along the rim of processes and the cell body: microtubules are concentrated along main processes and splay out into process tips and the cell body. In differentiated CG-4 oligodendrocytes, microfilaments are concentrated at the many process tips, in filopodia and in fine processes, but are not obvious in main processes where separate bundles of microtubules, which diverge at process branch points, are concentrated. gamma-tubulin, involved in microtubule nucleation, is concentrated at a small discrete area in the cell body, indicative of a microtubule organizing center. Polymerization of both actin and tubulin is required for initial process elaboration. Depolymerization of microtubules, but not of microfilaments, causes complete retraction of bipolar CG-4 cell processes. This process retraction does not occur if microfilaments are depolymerized first, indicating that process extension/retraction in motile bipolar CG-4 cells may occur by a balance of motor protein-driven forces as suggested for growth cone motility. Cytoskeleton organization in CG-4 cells is very similar to that reported for oligodendrocytes. CG-4 cells are thus a useful model for investigating the signals and mechanisms regulating oligodendrocyte process dynamics.
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Affiliation(s)
- Martin Rumsby
- Department of Biology, University of York, York, UK.
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30
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Abstract
Intracellular trafficking of membranes plays an essential role in the biogenesis and maintenance of myelin. The requisite proteins and lipids are transported from their sites of synthesis to myelin via vesicles. Vesicle transport is tightly coordinated with synthesis of lipids and proteins. To maintain the structural and functional organization of oligodendrocytes it is essential synchronize the various pathways of vesicle transport and to coordinate vesicle transport with reorganization of cytoskeleton. The systems that regulate the targeting of protein to myelin by vesicle transport are now being described. Here we review the current knowledge of these systems including those involved in (a) protein folding, (b) protein sorting and formation of carrier vesicles, (c) vesicle transport along elements of the cytoskeleton, and (d) vesicle targeting/fusion.
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Affiliation(s)
- J N Larocca
- Department of Neurology/Neuroscience, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
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Thomas MG, Santa Coloma TA, Correale J, Boccacci GL. Myosin light chain kinase inhibitors induce retraction of mature oligodendrocyte processes. Neurochem Res 2002; 27:1305-12. [PMID: 12512936 DOI: 10.1023/a:1021615530960] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Mature oligodendrocytes emit numerous myelinating processes. Force generating molecules are required for process outgrowth and spreading. We have analyzed the effect of the myosin II light chain kinase inhibitors ML-7 and ML-9 in cultured oligodendrocytes. Both drugs affect oligodendrocyte cell shape, provoking a retraction of high order processes. Our results suggest that the adhesion of the myelinating processes to the substrate depends on MLC phosphorylation, thus likely implicating myosin IIA.
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Affiliation(s)
- María G Thomas
- IIB Fundación Campomar, IIB FCEyN, University of Buenos Aires and IIBBA-CONICET, Buenos Aires, Argentina
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32
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Rodriguez-Gabin AG, Cammer M, Almazan G, Charron M, Larocca JN. Role of rRAB22b, an oligodendrocyte protein, in regulation of transport of vesicles from trans Golgi to endocytic compartments. J Neurosci Res 2001; 66:1149-60. [PMID: 11746448 DOI: 10.1002/jnr.1253] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Intracellular membrane trafficking plays an essential role in the biogenesis and maintenance of myelin. Members of the Rab protein family are important components of the systems that regulate intracellular vesicle transport. We examine the function of rRab22b, a novel rat Rab protein cloned from an oligodendrocyte cDNA library, by visualizing and identifying in living Hela cells the organelles that contain rRab22b. Our results show that rRab22b is present in the trans Golgi/TGN and endocytic compartments. Trafficking of membranes from trans Golgi to endocytic compartments takes place via small tubulo vesicular organelles containing rRab22b. The formation of vesicles in the trans Golgi also appears to be regulated by rRab22b. Additionally, our results suggest that rRab22b controls the transport of vesicles from the trans Golgi to endocytic compartments that localize in oligodendrocyte processes. That rRab22b is involved in the transport of certain proteins from trans Golgi to myelin is suggested by the evidence that certain proteins being targeted to the plasma membrane are first transported from trans Golgi to endocytic compartments.
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Affiliation(s)
- A G Rodriguez-Gabin
- Department of Neurology/Neuroscience, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY 10461, USA
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Song J, Goetz BD, Baas PW, Duncan ID. Cytoskeletal reorganization during the formation of oligodendrocyte processes and branches. Mol Cell Neurosci 2001; 17:624-36. [PMID: 11312599 DOI: 10.1006/mcne.2001.0974] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
During oligodendrocyte development, signals relevant to process formation must be transduced into appropriate changes in cytoskeletal organization. We have explored how microtubules and microfilaments interact during the outgrowth and branching of oligodendrocyte processes in culture. We observed that microfilaments are enriched in the peripheral region beneath the plasma membrane and constitute the major cytoskeletal element at the leading edge of the process, which is also enriched in the B-isoform of the non-muscle myosin II heavy chain. Microtubules form a dense bundle within the process and splay before extending into the leading edge and branches, following tracks laid by microfilaments. Pharmacologic disruption of microfilaments and microtubules compromised normal process outgrowth and branching. However, microtubules rapidly reinvaded most processes after removal of both antimicrotubule and antimicrofilament drugs, but the reinvasion was severely compromised if the antimicrofilament drug was retained. These results are consistent with the hypothesis that microfilaments guide the local reorganization of microtubules for the elongation of oligodendrocyte processes and the formation of new branches.
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Affiliation(s)
- J Song
- Department of Medical Science, University of Wisconsin, Madison 53706, USA
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Ingraham CA, Rising LJ. NBN defined medium supports the development of O4+/O1- immunopanned pro-oligodendroglia. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2000; 125:1-8. [PMID: 11154755 DOI: 10.1016/s0165-3806(00)00122-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Maintenance of immunopanned cells in culture medium in the absence of serum or pre-conditioning by other neural cell types such as astrocytes can be problematic. Here we report the novel use of a chemically defined medium, which we refer to as NBN since it contains N-2 supplement, B-27 supplement, and N-acetyl-L-cysteine, for maintaining O4+/O1- immunopanned pro-oligodendroglia. Since we had previously characterized O4+/O1- immunopanned pro-oligodendroglia in astrocyte-conditioned basal defined medium (BDM; [24]), we compared their proliferation and differentiation in NBN medium or in NBN medium containing 40% NBN medium pre-conditioned by astrocytes. At 4 DIC in NBN, 23% of O4+ cells were BrdU+ while in conditioned NBN medium, 91% of O4+ cells were BrdU+. At 7 DIC in either medium, less than 25% of O4+ cells were BrdU+. O4+/O1- immunopanned pro-oligodendroglia cultured in NBN medium developed extensive processes and membranous expansions characteristic of mature oligodendroglia. At 4 DIC in NBN medium, approximately 100% of cells were O4+, 80% were O1+, and 54% were MBP+. By contrast, at 4 DIC in conditioned NBN, 87% of cells were O4+, 12% were O1+, and 2% were MBP+. At 7 DIC, there were no differences in the percentages of cells that expressed O4, O1, or MBP in either NBN or conditioned NBN. These results indicate that NBN defined medium supports the development of O4+/O1- immunopanned pro-oligodendroglia, and promotes more rapid maturation than conditioned NBN. The ability to maintain cells of the oligodendroglial lineage immunopanned at specific developmental stages in NBN defined medium should facilitate studies designed to identify effects of growth factors or toxins on oligodendroglia.
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Affiliation(s)
- C A Ingraham
- Center for Neuropharmacology and Neuroscience, Albany Medical College, 47 New Scotland Avenue, Albany, New York, NY 12208, USA.
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Schmidt C, Ohlemeyer C, Kettenmann H, Reutter W, Horstkorte R. Incorporation of N-propanoylneuraminic acid leads to calcium oscillations in oligodendrocytes upon the application of GABA. FEBS Lett 2000; 478:276-80. [PMID: 10930582 DOI: 10.1016/s0014-5793(00)01868-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Sialylation of glycoproteins and glycolipids plays an important role during development, regeneration and pathogenesis. It has been shown that unnatural sialylation within glial cell cultures can have distinct effects on their proliferation and antigenic profiles. These cultures metabolize N-propanoylmannosamine (N-propanoylneuraminic acid precursor=P-NAP), a synthetic non-physiological precursor of neuraminic acid, resulting in the expression of N-propanoylneuraminic acid in glycoconjugates of their cell membranes [Schmidt, C., Stehling, P., Schnitzer, J., Reutter, W. and Horstkorte, R. (1998) J. Biol. Chem. 273, 19146-19152]. To determine whether these biochemically engineered sialic acids influence calcium concentrations in cells of the oligodendrocyte lineage, mixed glial cultures of oligodendrocytes growing on top of an astrocyte monolayer were exposed to glutamate, histamine, adrenaline, gamma-aminobutyric acid (GABA), high potassium (high K(+)) and ATP. Calcium responses in P-NAP-treated oligodendrocytes were determined by confocal microscopy with the calcium indicator fluo-3 AM, and compared with control cultures. We showed that P-NAP differentially modulated the calcium responses of individual oligodendrocytes when GABA was applied. GABA induced calcium oscillations with up to four spikes per min in 60% of oligodendrocytes when treated with P-NAP.
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Affiliation(s)
- C Schmidt
- Max Delbrück Centrum für Molekulare Medizin, Berlin-Buch, Germany.
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Anderson ES, Bjartmar C, Eriksson C, Westermark G, Hildebrand C. Developing chicken oligodendrocytes express the type IV oligodendrocyte marker T4-O in situ, but not in vitro. Neurosci Lett 2000; 284:21-4. [PMID: 10771152 DOI: 10.1016/s0304-3940(00)00989-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Accumulating data suggest that the oligodendrocyte population includes morphological and biochemical subtypes. We recently reported that a polyclonal antiserum against an unknown antigen, the T4-O molecule, labels a subpopulation of chicken oligodendrocytes, obviously representing the type IV variety of Del Rio Hortega. The present study examines the developmental expression of the T4-O molecule in situ and in vitro. The results show that T4-O immunoreactive cells first appear at E15 in the ventral funiculus. But, oligodendrocytes cultured in vitro with or without neurones do not develop a T4-O immunoreactivity. We conclude that oligodendrocytes in the spinal cord of chicken embryos first express the T4-O molecule some time after onset of myelination, and that the T4-O immunoreactive phenotype does not develop in vitro.
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Affiliation(s)
- E S Anderson
- Department of Biomedicine and Surgery, Division of Cell Biology, Faculty of Health Sciences, University of Linköping, SE-581 85, Linköping, Sweden.
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Canoll PD, Kraemer R, Teng KK, Marchionni MA, Salzer JL. GGF/neuregulin induces a phenotypic reversion of oligodendrocytes. Mol Cell Neurosci 1999; 13:79-94. [PMID: 10192767 DOI: 10.1006/mcne.1998.0733] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
We have previously shown that glial growth factor (GGF), a member of the neuregulin (NRG) family of growth factors, is a mitogen and survival factor for oligodendrocyte progenitors in cell culture and blocks their differentiation at the pro-oligodendrocyte stage (P. D. Canoll et al., 1996, Neuron 17, 229-243). We now show that GGF is able to induce differentiated oligodendrocytes to undergo a phenotypic reversion characterized by loss of MBP expression, reexpression of the intermediate filament protein nestin, reorganization of the actin cytoskeleton, and a dramatic reduction in the number of processes per cell. TUNEL analysis demonstrates that GGF is not cytotoxic for mature oligodendrocytes, but rather enhances their survival. GGF also induces the rapid activation of the PI 3-kinase and MAP kinase signaling pathways. These results further support a role for the NRGs in promoting the proliferation and survival of and inhibiting the differentiation of cells in the oligodendrocyte lineage and demonstrate that oligodendrocytes that differentiate in culture retain a substantial degree of phenotypic plasticity.
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Affiliation(s)
- P D Canoll
- Department of Pharmacology, New York University Medical School, 550 First Avenue, New York, New York 10016, USA
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Abstract
The oligodendrocyte is the glial cell responsible for the formation and maintenance of CNS myelin. Because the development of neuronal morphology is known to depend on the presence of highly organized microtubule arrays, it may be hypothesized that the properties of microtubules influence the form and function of oligodendrocytes. The goals of the present study were to define the physical attributes of microtubules in oligodendrocytes maintained in vitro. The results of electron and confocal microscopy indicate that microtubules are present throughout the cell bodies and large and small processes of oligodendrocytes and are rarely associated with discrete microtubule-organizing centers. A modified "hooking" protocol demonstrated that the polarity orientation of microtubules is uniformly plus-end distal in small oligodendrocyte processes, compared with a nonuniform, predominantly plus-end distal orientation in large processes. Oligodendrocytes were exposed to the microtubule-depolymerizing drug nocodazole to examine microtubule stability in these cells. The results suggest that oligodendrocyte microtubules can be resolved into at least three distinct microtubule populations that differ in their kinetics of depolymerization in the presence of nocodazole. These findings suggest that the properties of the oligodendrocyte microtubule array reflect the functions of the different regions of this highly specialized cell.
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41
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Bambrick LL, de Grip A, Seenivasan V, Krueger BK, Yarowsky PJ. Expression of glial antigens in mouse astrocytes: species differences and regulation in vitro. J Neurosci Res 1996; 46:305-15. [PMID: 8933369 DOI: 10.1002/(sici)1097-4547(19961101)46:3<305::aid-jnr3>3.0.co;2-o] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Expression of developmentally regulated antigens was used to characterize glial cells in cultures from embryonic mouse cerebral cortex. Over 90% of the cells had a flat morphology, and about 50% of these flat cells also expressed the ganglioside GD3. Up to 40% of all the GD3 expressing cells also expressed A2B5 antigen. Flat cells expressing either glial fibrillary acidic protein (GFAP), or GD3 or both were present at all times in vitro. These three populations of flat cells could not be further distinguished on the basis of NG2 or fibronectin expression, or with respect to their responses to the mitogens FGF-2, PDGF, or EGF. The glial cultures also contain a small number (approximately 5%) of process bearing cells with the morphological and immunocytochemical characteristics of oligodendrocyte precursors. The expression of GD3 by flat cells changed with time in culture as the fraction of flat cells expressing only GD3 declined and the fraction of cells expressing GFAP (with or without GD3) increased. The data are consistent with those flat cells expressing only GD3 being astrocyte precursors. Furthermore, between 1 and 3 weeks in vitro GD3/GFAP cells lose GD3 while retaining GFAP. Cells expressing only GFAP could be induced to express GD3 and A2B5 by treatment with FGF-2. The widespread and regulated expression of GD3 and A2B5 by murine glia is different from the restricted pattern of expression previously reported for these antigens in rat brain cell cultures. These results demonstrate that expression of GD3 and A2B5 by murine astrocytes depends on both culture age and extracellular signals and that these gangliosides are not markers for cell lineage in the mouse.
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Affiliation(s)
- L L Bambrick
- Department of Physiology, University of Maryland School of Medicine, Baltimore 21201, USA
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42
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LoPresti P, Szuchet S, Papasozomenos SC, Zinkowski RP, Binder LI. Functional implications for the microtubule-associated protein tau: localization in oligodendrocytes. Proc Natl Acad Sci U S A 1995; 92:10369-73. [PMID: 7479786 PMCID: PMC40798 DOI: 10.1073/pnas.92.22.10369] [Citation(s) in RCA: 285] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
We present evidence that the microtubule-associated protein tau is present in oligodendrocytes (OLGs), the central nervous system cells that make myelin. By showing that tau is distributed in a pattern similar to that of myelin basic protein, our results suggest a possible involvement of tau in some aspect of myelination. Tau protein has been identified in OLGs in situ and in vitro. In interfascicular OLGs, tau localization, revealed by monoclonal antibody Tau-5, was confined to the cell somata. However, in cultured ovine OLGs with an exuberant network of processes, tau was detected in cell somata, cellular processes, and membrane expansions at the tips of these processes. Moreover, in such cultures, tau appeared localized adjacent to or coincident with myelin basic protein in membrane expansions along and at the ends of the cellular processes. The presence of tau mRNA was documented using fluorescence in situ hybridization. The distribution of the tau mRNA was similar to that of the tau protein. Western blot analysis of cultured OLGs showed the presence of many tau isoforms. Together, these results demonstrate that tau is a genuine oligodendrocyte protein and pave the way for determining its functional role in these cells.
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Affiliation(s)
- P LoPresti
- Molecular Geriatrics Corporation, Lake Bluff, IL 60044, USA
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43
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Xie D, Schultz RL, Whitter EF. The oligodendroglial reaction to brain stab wounds: an immunohistochemical study. JOURNAL OF NEUROCYTOLOGY 1995; 24:435-48. [PMID: 7595660 DOI: 10.1007/bf01181605] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Myelin/oligodendrocyte specific protein was compared to glial fibrillary acidic protein and 2'3'-cyclic nucleotide 3'-phosphodiesterase expression in normal rat brains and following stab wounds to the cerebral cortex, corpus callosum and hippocampus. Animals with stab wounds were allowed to recover for 5, 15, 28, 45 and 70 days post-operation before fixation by perfusion. Sections were reacted with antibodies against myelin/oligodendrocyte specific protein, glial fibrillary acidic protein and 2'3'-cyclic nucleotide 3'-phosphodiesterase, and observed by light and electron microscopy. Normal cerebral cortex had very few myelin/oligodendrocyte specific protein-positive and 2'3'-cyclic nucleotide 3'-phosphodiesterase-positive cells, but some glial fibrillary acidic protein-positive cells. The myelinated fibres of the corpus callosum were heavily stained for myelin/oligodendrocyte specific protein but unstained by glial fibrillary acidic protein or 2'3'-cyclic nucleotide 3'-phosphodiesterase antibodies. Some immunopositive cells were present in the corpus callosum and hippocampus with all three antibodies. After stab wound myelin/oligodendrocyte specific protein-positive reactive cells had more and longer processes and stained more intensely than equivalent cells in normal brain. These cells were distributed along the wound track, including within the cerebral cortex. The numbers of these cells increased until 28 days post-operation and then decreased so that very few were found at 70 days post-operation except in the corpus callosum. Where demyelination occurred myelin/oligodendrocyte specific protein-staining was lost. Staining for 2'3-cyclic nucleotide 3'-phosphodiesterase revealed a similar pattern. Glial fibrillary acidic protein-positive reactive cells, which were also more robust than the normal cells, were more widely distributed. They increased in number throughout the time periods studied and gliosis was evident on the contralateral side. The glial fibrillary acidic protein-positive astrocytes were also different from the myelin/oligodendrocyte specific protein-positive and 2'3'-cyclic nucleotide 3'-phosphodiesterase-positive oligodendrocytes in terms of cell shape. With electron microscopy myelin/oligodendrocyte specific protein-positive cells showed features typical of immature oligodendrocytes. We conclude that the injury caused a numerical increase in oligodendrocytes and that myelin/oligodendrocyte specific protein is a good marker for the oligodendroglial response and demyelination in pathological conditions.
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Affiliation(s)
- D Xie
- Department of Pathology and Human Anatomy, School of Medicine, Loma Linda University, CA 92350, USA
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Ainger K, Avossa D, Morgan F, Hill SJ, Barry C, Barbarese E, Carson JH. Transport and localization of exogenous myelin basic protein mRNA microinjected into oligodendrocytes. J Cell Biol 1993; 123:431-41. [PMID: 7691830 PMCID: PMC2119827 DOI: 10.1083/jcb.123.2.431] [Citation(s) in RCA: 392] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
We have studied transport and localization of MBP mRNA in oligodendrocytes in culture by microinjecting labeled mRNA into living cells and analyzing the intracellular distribution of the injected RNA by confocal microscopy. Injected mRNA initially appears dispersed in the perikaryon. Within minutes, the RNA forms granules which, in the case of MBP mRNA, are transported down the processes to the periphery of the cell where the distribution again becomes dispersed. In situ hybridization shows that endogenous MBP mRNA in oligodendrocytes also appears as granules in the perikaryon and processes and dispersed in the peripheral membranes. The granules are not released by extraction with non-ionic detergent, indicating that they are associated with the cytoskeletal matrix. Three dimensional visualization indicates that MBP mRNA granules are often aligned in tracks along microtubules traversing the cytoplasm and processes. Several distinct patterns of granule movement are observed. Granules in the processes undergo sustained directional movement with a velocity of approximately 0.2 micron/s. Granules at branch points undergo oscillatory motion with a mean displacement of 0.1 micron/s. Granules in the periphery of the cell circulate randomly with a mean displacement of approximately 1 micron/s. The results are discussed in terms of a multi-step pathway for transport and localization of MBP mRNA in oligodendrocytes. This work represents the first characterization of intracellular movement of mRNA in living cells, and the first description of the role of RNA granules in transport and localization of mRNA in cells.
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Affiliation(s)
- K Ainger
- Department of Biochemistry, University of Connecticut Health Center, Farmington 06030
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Vignais L, Nait Oumesmar B, Mellouk F, Gout O, Labourdette G, Baron-Van Evercooren A, Gumpel M. Transplantation of oligodendrocyte precursors in the adult demyelinated spinal cord: migration and remyelination. Int J Dev Neurosci 1993; 11:603-12. [PMID: 8116473 DOI: 10.1016/0736-5748(93)90049-j] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
A demyelinating lesion induced by an injection of lysolecithin into the spinal cord can be partly repaired by oligodendrocyte precursors transplanted at a distance of 6-8 mm from the lesion. Using a non-toxic fluorescent dye (Hoechst 33342) as a cell marker, we demonstrate that transplanted oligodendrocyte precursors from different origins (periventricular zone fragments from newborn mouse and cultured rat oligodendrocyte progenitor cells) can migrate along specific pathways (i.e. white matter fasciculi, ependymal wall, meninges and blood vessels). These cells can be attracted when passing at the vicinity of the lesion as well as differentiate and remyelinate axons with the lesion. Myelin repair thus appears to be the result of distinct successive events: migration, specific attraction, differentiation and myelination. This can occur in both shiverer and normal adult hosts.
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Affiliation(s)
- L Vignais
- INSERM U-134, Hôpital de la Salpêtrière, Paris, France
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46
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Ludwin SK, Szuchet S. Myelination by mature ovine oligodendrocytes in vivo and in vitro: evidence that different steps in the myelination process are independently controlled. Glia 1993; 8:219-31. [PMID: 8406679 DOI: 10.1002/glia.440080402] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The ability of isolated mature post-myelination ovine oligodendrocytes to myelinate was investigated in tissue culture and in vivo. In culture, although the cells adhered preferentially to rat dorsal root ganglia (DRG) axons, sent out processes that encircled and wrapped them, proliferated, and synthesised myelin proteins (MBP), no myelination was found. This failure to find myelination occurred despite the fact that the oligodendrocytes both in the present experiments and in previous studies elaborated membranous structures that have been shown chemically and structurally to be similar to normal central nervous system myelin. These findings contrasted with those seen when neonatal rodent glial cells were added to similar DRG neuron cultures, in which myelination readily occurred. When the same adult ovine oligodendrocytes were transplanted into the brains of Shiverer mice, normal compact myelin was formed, proving that the cells were capable of myelination and suggesting that cross-species incompatibility was probably not a major factor in the lack of myelination in vitro. It is possible that the failure of ovine oligodendrocytes to myelinate DRG axons is due either to the relatively low number of supporting glial cells, such as astrocytes or microglia which may be necessary for satisfactory myelination, or that some other factor in the microenvironment is lacking; in any event, these results point to the complexity of oligodendrocyte-axon interactions. It is clear that each of the events, from adherence to proliferation to wrapping and the myelin compaction may be under the control of a different signal and may operate through a distinct mechanism, even though each process is dependent on the other. The results also point to the potential usefulness of this model system for deciphering such signals and mechanisms.
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Affiliation(s)
- S K Ludwin
- Department of Pathology, University of Western Ontario, London, Canada
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47
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Fawcett JW, Fersht N, Housden L, Schachner M, Pesheva P. Axonal growth on astrocytes is not inhibited by oligodendrocytes. J Cell Sci 1992; 103 ( Pt 2):571-9. [PMID: 1478956 DOI: 10.1242/jcs.103.2.571] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Axon growth in vitro may be inhibited by contact with oligodendrocytes, but most axons grow readily on the surface of astrocyte monolayers. Since both cell types are in close contact with one another in the damaged nervous system, we have examined the growth of axons on cultures which contain both astrocytes and oligodendrocytes. Cultures derived from neonatal rat forebrain develop with a monolayer of large flat astrocytes attached to the culture dish, and with many smaller cells of the oligodendrocyte lineage on their surface. Dorsal root ganglia placed on these cultures grow axons readily, the overall extent of growth being unaffected by the presence or absence of oligodendrocytes, many of which express galactocerebroside and the inhibitory molecule janusin. A previous set of experiments had shown that growth of these axons is inhibited by oligodendrocytes by themselves. Scanning electron microscopy coupled with silver-intensified immunostaining reveals that the axons grow on the surface of the astrocytic layer, underneath the oligodendrocytes, and are therefore in contact with both cell types as they grow. The presence of astrocytes therefore alters the results of axonal contact with oligodendrocytes.
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Affiliation(s)
- J W Fawcett
- Physiological Laboratory, Cambridge, England
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48
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Barbarese E. Spatial distribution of myelin basic protein mRNA and polypeptide in quaking oligodendrocytes in culture. J Neurosci Res 1991; 29:271-81. [PMID: 1717701 DOI: 10.1002/jnr.490290302] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In the CNS, myelin is formed from the expansion of oligodendrocyte processes. In order to study myelin assembly in the hypomyelinating mutant mouse quaking (qk), cultures of oligodendrocytes were established from affected and control animals. The cytoarchitecture of the oligodendrocytes was analyzed by performing morphometric measurements after immunostaining with antitubulin. The results indicate that the gross morphology of the processes is similar in control and mutant cells. The localization of the message for the myelin structural component, myelin basic protein (MBP), was examined by in situ hybridization. In control oligodendrocytes, 80% of MBP mRNA is found in the processes. In contrast, only 23% of MBP mRNA is localized to these structures in the mutant; the majority of MBP mRNA remains in the cell body. The mutant cells are capable of distributing mRNAs to the periphery as shown by the presence of tubulin mRNA in their processes. MBP polypeptide was visualized by immunofluorescence and found in the perikaryon, processes and membranous expansions of the control cells. In the mutant, it is largely confined to the perikaryon, reflecting the distribution of the mRNA. These results suggest that the localization of MBP polypeptide is achieved by restricting the distribution of its mRNA, and that MBP assembly into the myelin membrane occurs in the processes. This step appears to be blocked in qk oligodendrocytes in culture.
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Affiliation(s)
- E Barbarese
- Department of Neurology, University of Connecticut Health Center, Farmington 06032
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49
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Pearce-Kelling S, Mitchell WJ, Summers BA, Appel MJ. Virulent and attenuated canine distemper virus infects multiple dog brain cell types in vitro. Glia 1991; 4:408-16. [PMID: 1834561 PMCID: PMC7165944 DOI: 10.1002/glia.440040409] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Canine Distemper Virus (CDV) produces an encephalitis in dogs that varies with viral strain. We have studied the cell tropisms of two virulent strains (CDV-SH and CDV A75-17) and an attenuated strain, Rockborn (CDV-RO), in cultured canine brain cells. Infected cell types were identified by double immunofluorescent labeling of specific cell markers and viral antigens. All viral strains studied produced infection in astrocytes, fibroblasts, and macrophages. Neurons were not infected by CDV A75-17 but were rapidly infected by CDV-SH and CDV-RO. Multipolar oligodendrocytes were very rarely infected by any of the virus strains. In contrast, a morphologically distinct subset of bipolar oligodendrocytes were commonly infected by CDV-SH and CDV-RO. The kinetics of infection in the astrocytes, oligodendrocytes, neurons, and macrophages varied between strains. Both CDV-SH and CDV-RO rapidly infected bipolar oligodendrocytes, astrocytes, neurons, and macrophages by 14 days post infection while infection by CDV A75-17 was delayed until after 28-35 days post infection. The differences in the growth kinetics and cell tropisms for some brain cells, exhibited by the three viral strains examined in this in vitro study, may relate to the different CNS symptoms that these strains produce in vivo.
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Affiliation(s)
- S Pearce-Kelling
- Department of Pathology, New York State College of Veterinary Medicine, Cornell University, Ithaca 14853
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50
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Smith TG, Behar TN, Lange GD, Marks WB, Sheriff WH. A fractal analysis of cultured rat optic nerve glial growth and differentiation. Neuroscience 1991; 41:159-66. [PMID: 2057059 DOI: 10.1016/0306-4522(91)90206-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Fractal dimension can be used as a quantitative measure of morphological complexity. Separate, enriched populations of oligodendrocytes or type 2 astrocytes derived from neonatal rat optic nerves were allowed to differentiate in vitro. Fractal dimensions of differentiating glial cells were measured over time. The fractal dimension correlated with perceived complexity and increased in value as the glial cells matured. Analysis of the changes in fractal dimension with time revealed unique rates of growth and differentiation for each glial phenotype.
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Affiliation(s)
- T G Smith
- Laboratory of Neurophysiology, NINDS, National Institutes of Health, Bethesda, MD 20892
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