1
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Osso LA, Hughes EG. Dynamics of mature myelin. Nat Neurosci 2024; 27:1449-1461. [PMID: 38773349 DOI: 10.1038/s41593-024-01642-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 04/05/2024] [Indexed: 05/23/2024]
Abstract
Myelin, which is produced by oligodendrocytes, insulates axons to facilitate rapid and efficient action potential propagation in the central nervous system. Traditionally viewed as a stable structure, myelin is now known to undergo dynamic modulation throughout life. This Review examines these dynamics, focusing on two key aspects: (1) the turnover of myelin, involving not only the renewal of constituents but the continuous wholesale replacement of myelin membranes; and (2) the structural remodeling of pre-existing, mature myelin, a newly discovered form of neural plasticity that can be stimulated by external factors, including neuronal activity, behavioral experience and injury. We explore the mechanisms regulating these dynamics and speculate that myelin remodeling could be driven by an asymmetry in myelin turnover or reactivation of pathways involved in myelin formation. Finally, we outline how myelin remodeling could have profound impacts on neural function, serving as an integral component of behavioral adaptation.
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Affiliation(s)
- Lindsay A Osso
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Ethan G Hughes
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA.
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2
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Leenders F, Koole L, Slaets H, Tiane A, Hove DVD, Vanmierlo T. Navigating oligodendrocyte precursor cell aging in brain health. Mech Ageing Dev 2024; 220:111959. [PMID: 38950628 DOI: 10.1016/j.mad.2024.111959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Revised: 06/17/2024] [Accepted: 06/24/2024] [Indexed: 07/03/2024]
Abstract
Oligodendrocyte precursor cells (OPCs) comprise 5-8 % of the adult glial cell population and stand out as the most proliferative cell type in the central nervous system (CNS). OPCs are responsible for generating oligodendrocytes (OLs), the myelinating cells of the CNS. However, OPC functions decline as we age, resulting in impaired differentiation and inadequate remyelination. This review explores the cellular and molecular changes associated with OPC aging, and their impact on OPC differentiation and functionality. Furthermore, it examines the impact of OPC aging within the context of multiple sclerosis and Alzheimer's disease, both neurodegenerative conditions wherein aged OPCs exacerbate disease progression by impeding remyelination. Moreover, various pharmacological interventions targeting pathways related to senescence and differentiation are discussed as potential strategies to rejuvenate aged OPCs. Enhancing our understanding of OPC aging mechanisms holds promise for developing new therapies to improve remyelination and repair in age-related neurodegenerative disorders.
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Affiliation(s)
- Freddy Leenders
- Department Psychiatry and Neuropsychology, Division Translational Neuroscience, Mental Health and Neuroscience Research Institute, Maastricht University, Maastricht, the Netherlands; Department of Neuroscience, Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium
| | - Lisa Koole
- Department Psychiatry and Neuropsychology, Division Translational Neuroscience, Mental Health and Neuroscience Research Institute, Maastricht University, Maastricht, the Netherlands; Department of Neuroscience, Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium
| | - Helena Slaets
- University MS Centre (UMSC) Hasselt, Pelt, Belgium; Neuro-Immune Connections and Repair Lab, Department of Immunology and Infection, Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
| | - Assia Tiane
- Department Psychiatry and Neuropsychology, Division Translational Neuroscience, Mental Health and Neuroscience Research Institute, Maastricht University, Maastricht, the Netherlands; Department of Neuroscience, Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium; University MS Centre (UMSC) Hasselt, Pelt, Belgium
| | - Daniel van den Hove
- Department Psychiatry and Neuropsychology, Division Translational Neuroscience, Mental Health and Neuroscience Research Institute, Maastricht University, Maastricht, the Netherlands
| | - Tim Vanmierlo
- Department Psychiatry and Neuropsychology, Division Translational Neuroscience, Mental Health and Neuroscience Research Institute, Maastricht University, Maastricht, the Netherlands; Department of Neuroscience, Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium; University MS Centre (UMSC) Hasselt, Pelt, Belgium.
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3
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Craig GA, Ryan L, Thapar J, McNamara NB, Hoffmann A, Page D, Rose J, Cox SR, Miron VE. Reflective imaging of myelin integrity in the human and mouse central nervous systems. Front Cell Neurosci 2024; 18:1408182. [PMID: 39049821 PMCID: PMC11266064 DOI: 10.3389/fncel.2024.1408182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Accepted: 06/13/2024] [Indexed: 07/27/2024] Open
Abstract
The structural integrity of myelin sheaths in the central nervous system (CNS) is crucial for the maintenance of its function. Electron microscopy (EM) is the gold standard for visualizing individual myelin sheaths. However, the tissue processing involved can induce artifacts such as shearing of myelin, which can be difficult to distinguish from true myelin abnormalities. Spectral confocal reflectance (SCoRe) microscopy is an imaging technique that leverages the differential refractive indices of compacted CNS myelin in comparison to surrounding parenchyma to detect individual compact myelin internodes with reflected light, positioning SCoRe as a possible complementary method to EM to assess myelin integrity. Whether SCoRe is sensitive enough to detect losses in myelin compaction when myelin quantity is otherwise unaffected has not yet been directly tested. Here, we assess the capacity of SCoRe to detect differences in myelin compaction in two mouse models that exhibit a loss of myelin compaction without demyelination: microglia-deficient mice (Csf1r-FIRE Δ/Δ) and wild-type mice fed with the CSF1R inhibitor PLX5622. In addition, we compare the ability to detect compact myelin sheaths using SCoRe in fixed-frozen versus paraffin-embedded mouse tissue. Finally, we show that SCoRe can successfully detect individual sheaths in aged human paraffin-embedded samples of deep white matter regions. As such, we find SCoRe to be an attractive technique to investigate myelin integrity, with sufficient sensitivity to detect myelin ultrastructural abnormalities and the ability to perform equally well in tissue preserved using different methods.
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Affiliation(s)
- Georgina A. Craig
- Keenan Research Centre for Biomedical Science, St. Michael’s Hospital, Unity Health Toronto, Toronto, ON, Canada
- United Kingdom Dementia Research Institute, The University of Edinburgh, Edinburgh, United Kingdom
| | - Lucy Ryan
- United Kingdom Dementia Research Institute, The University of Edinburgh, Edinburgh, United Kingdom
| | - Jessica Thapar
- Department of Immunology, The University of Toronto, Toronto, ON, Canada
| | - Niamh B. McNamara
- United Kingdom Dementia Research Institute, The University of Edinburgh, Edinburgh, United Kingdom
| | - Alana Hoffmann
- Keenan Research Centre for Biomedical Science, St. Michael’s Hospital, Unity Health Toronto, Toronto, ON, Canada
- United Kingdom Dementia Research Institute, The University of Edinburgh, Edinburgh, United Kingdom
| | - Danielle Page
- Lothian Birth Cohorts, The University of Edinburgh, Edinburgh, United Kingdom
| | - Jamie Rose
- United Kingdom Dementia Research Institute, The University of Edinburgh, Edinburgh, United Kingdom
| | - Simon R. Cox
- Lothian Birth Cohorts, The University of Edinburgh, Edinburgh, United Kingdom
| | - Veronique E. Miron
- Keenan Research Centre for Biomedical Science, St. Michael’s Hospital, Unity Health Toronto, Toronto, ON, Canada
- United Kingdom Dementia Research Institute, The University of Edinburgh, Edinburgh, United Kingdom
- Department of Immunology, The University of Toronto, Toronto, ON, Canada
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4
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Masson MA, Nait-Oumesmar B. Emerging concepts in oligodendrocyte and myelin formation, inputs from the zebrafish model. Glia 2023; 71:1147-1163. [PMID: 36645033 DOI: 10.1002/glia.24336] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/20/2022] [Accepted: 12/29/2022] [Indexed: 01/17/2023]
Abstract
Oligodendrocytes (OLs) are the myelinating cells of the central nervous system (CNS), which are derived from OL precursor cells. Myelin insulates axons allowing the saltatory conduction of action potentials and also provides trophic and metabolic supports to axons. Interestingly, oligodendroglial cells have the capacity to sense neuronal activity, which regulates myelin sheath formation via the vesicular release of neurotransmitters. Neuronal activity-dependent regulation of myelination is mediated by specialized interaction between axons and oligodendroglia, involving both synaptic and extra-synaptic modes of communications. The zebrafish has provided key advantages for the study of the myelination process in the CNS. External development and transparent larval stages of this vertebrate specie combined with the existence of several transgenic reporter lines provided key advances in oligodendroglial cell biology, axo-glial interactions and CNS myelination. In this publication, we reviewed and discussed the most recent knowledge on OL development and myelin formation, with a focus on mechanisms regulating these fundamental biological processes in the zebrafish. Especially, we highlighted the critical function of axons and oligodendroglia modes of communications and calcium signaling in myelin sheath formation and growth. Finally, we reviewed the relevance of these knowledge's in demyelinating diseases and drug discovery of pharmacological compounds favoring myelin regeneration.
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Affiliation(s)
- Mary-Amélie Masson
- Sorbonne Université, Institut du Cerveau, Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Brahim Nait-Oumesmar
- Sorbonne Université, Institut du Cerveau, Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié-Salpêtrière, Paris, France
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5
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Chapman TW, Olveda GE, Bame X, Pereira E, Hill RA. Oligodendrocyte death initiates synchronous remyelination to restore cortical myelin patterns in mice. Nat Neurosci 2023; 26:555-569. [PMID: 36928635 PMCID: PMC10208560 DOI: 10.1038/s41593-023-01271-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 02/09/2023] [Indexed: 03/18/2023]
Abstract
Myelin degeneration occurs in neurodegenerative diseases and aging. In these conditions, resident oligodendrocyte progenitor cells (OPCs) differentiate into oligodendrocytes that carry out myelin repair. To investigate the cellular dynamics underlying these events, we developed a noninflammatory demyelination model that combines intravital two-photon imaging with a single-cell ablation technique called two-photon apoptotic targeted ablation (2Phatal). Oligodendrocyte 2Phatal in both sexes results in a myelin degeneration cascade that triggers rapid forms of synchronous remyelination on defined axons. This remyelination is driven by oligodendrocytes differentiated from a subset of morphologically distinct, highly branched OPCs. Moreover, remyelination efficiency depends on the initial myelin patterns, as well as the age of the organism. In summary, using 2Phatal, we show a form of rapid synchronous remyelination, mediated by a distinct subset of OPCs, capable of restoring the original myelin patterning in adulthood but not aging.
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Affiliation(s)
- Timothy W Chapman
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA
| | - Genaro E Olveda
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA
| | - Xhoela Bame
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA
| | - Elizabeth Pereira
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA
| | - Robert A Hill
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA.
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6
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Djannatian M, Radha S, Weikert U, Safaiyan S, Wrede C, Deichsel C, Kislinger G, Rhomberg A, Ruhwedel T, Campbell DS, van Ham T, Schmid B, Hegermann J, Möbius W, Schifferer M, Simons M. Myelination generates aberrant ultrastructure that is resolved by microglia. J Biophys Biochem Cytol 2023; 222:213804. [PMID: 36637807 PMCID: PMC9856851 DOI: 10.1083/jcb.202204010] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 10/18/2022] [Accepted: 12/21/2022] [Indexed: 01/14/2023] Open
Abstract
To enable rapid propagation of action potentials, axons are ensheathed by myelin, a multilayered insulating membrane formed by oligodendrocytes. Most of the myelin is generated early in development, resulting in the generation of long-lasting stable membrane structures. Here, we explored structural and dynamic changes in central nervous system myelin during development. To achieve this, we performed an ultrastructural analysis of mouse optic nerves by serial block face scanning electron microscopy (SBF-SEM) and confocal time-lapse imaging in the zebrafish spinal cord. We found that myelin undergoes extensive ultrastructural changes during early postnatal development. Myelin degeneration profiles were engulfed and phagocytosed by microglia using exposed phosphatidylserine as one "eat me" signal. In contrast, retractions of entire myelin sheaths occurred independently of microglia and involved uptake of myelin by the oligodendrocyte itself. Our findings show that the generation of myelin early in development is an inaccurate process associated with aberrant ultrastructural features that require substantial refinement.
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Affiliation(s)
- Minou Djannatian
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany,https://ror.org/043j0f473German Center for Neurodegenerative Diseases, Munich, Germany,Department of Neurology, Klinikum rechts der Isar, TUM School of Medicine, Technical University of Munich, Munich, Germany,Munich Cluster of Systems Neurology (SyNergy), Munich, Germany,Minou Djannatian:
| | - Swathi Radha
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany,https://ror.org/043j0f473German Center for Neurodegenerative Diseases, Munich, Germany
| | - Ulrich Weikert
- Max-Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Shima Safaiyan
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany,https://ror.org/043j0f473German Center for Neurodegenerative Diseases, Munich, Germany
| | - Christoph Wrede
- https://ror.org/00f2yqf98Institute of Functional and Applied Anatomy, Research Core Unit Electron Microscopy, Hannover Medical School, Hannover, Germany
| | - Cassandra Deichsel
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany,https://ror.org/043j0f473German Center for Neurodegenerative Diseases, Munich, Germany
| | - Georg Kislinger
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany,https://ror.org/043j0f473German Center for Neurodegenerative Diseases, Munich, Germany
| | - Agata Rhomberg
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany,https://ror.org/043j0f473German Center for Neurodegenerative Diseases, Munich, Germany
| | - Torben Ruhwedel
- Max-Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Douglas S. Campbell
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany,https://ror.org/043j0f473German Center for Neurodegenerative Diseases, Munich, Germany
| | - Tjakko van Ham
- https://ror.org/018906e22Department of Clinical Genetics, Erasmus University Medical Center, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Bettina Schmid
- https://ror.org/043j0f473German Center for Neurodegenerative Diseases, Munich, Germany
| | - Jan Hegermann
- https://ror.org/00f2yqf98Institute of Functional and Applied Anatomy, Research Core Unit Electron Microscopy, Hannover Medical School, Hannover, Germany
| | - Wiebke Möbius
- Max-Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Martina Schifferer
- https://ror.org/043j0f473German Center for Neurodegenerative Diseases, Munich, Germany,Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
| | - Mikael Simons
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany,https://ror.org/043j0f473German Center for Neurodegenerative Diseases, Munich, Germany,Munich Cluster of Systems Neurology (SyNergy), Munich, Germany,Institute for Stroke and Dementia Research, University Hospital of Munich, Ludwig Maximilian University of Munich, Munich, Germany,Correspondence to Mikael Simons:
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7
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Talidou A, Frankland PW, Mabbott D, Lefebvre J. Homeostatic coordination and up-regulation of neural activity by activity-dependent myelination. NATURE COMPUTATIONAL SCIENCE 2022; 2:665-676. [PMID: 38177260 DOI: 10.1038/s43588-022-00315-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 08/10/2022] [Indexed: 01/06/2024]
Abstract
Activity-dependent myelination (ADM) is a fundamental dimension of brain plasticity through which myelin changes as a function of neural activity. Mediated by structural changes in glia, ADM notably regulates axonal conduction velocity. Yet, it remains unclear how neural activity impacts myelination to orchestrate the timing of neural signalling, and how ADM shapes neural activity. We developed a model of spiking neurons enhanced with neuron-oligodendrocyte feedback and examined the relationship between ADM and neural activity. We found that ADM implements a homeostatic gain control mechanism that enhances neural firing rates and correlations through the temporal coordination of action potentials as axon lengths increase. Stimuli engage ADM plasticity to trigger bidirectional and reversible changes in conduction delays, as may occur during learning. Furthermore, ADM was found to enhance information transmission under various types of time-varying stimuli. These results highlight the role of ADM in shaping neural activity and communication.
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Affiliation(s)
- Afroditi Talidou
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada.
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.
| | - Paul W Frankland
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada
| | - Donald Mabbott
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada
| | - Jérémie Lefebvre
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Physics, University of Ottawa, Ottawa, Ontario, Canada
- Department of Mathematics, University of Toronto, Toronto, Ontario, Canada
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8
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Bacmeister CM, Huang R, Osso LA, Thornton MA, Conant L, Chavez AR, Poleg-Polsky A, Hughes EG. Motor learning drives dynamic patterns of intermittent myelination on learning-activated axons. Nat Neurosci 2022; 25:1300-1313. [PMID: 36180791 PMCID: PMC9651929 DOI: 10.1038/s41593-022-01169-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 08/18/2022] [Indexed: 01/10/2023]
Abstract
Myelin plasticity occurs when newly formed and pre-existing oligodendrocytes remodel existing patterns of myelination. Myelin remodeling occurs in response to changes in neuronal activity and is required for learning and memory. However, the link between behavior-induced neuronal activity and circuit-specific changes in myelination remains unclear. Using longitudinal in vivo two-photon imaging and targeted labeling of learning-activated neurons in mice, we explore how the pattern of intermittent myelination is altered on individual cortical axons during learning of a dexterous reach task. We show that behavior-induced myelin plasticity is targeted to learning-activated axons and occurs in a staged response across cortical layers in the mouse primary motor cortex. During learning, myelin sheaths retract, which results in lengthening of nodes of Ranvier. Following motor learning, addition of newly formed myelin sheaths increases the number of continuous stretches of myelination. Computational modeling suggests that motor learning-induced myelin plasticity initially slows and subsequently increases axonal conduction speed. Finally, we show that both the magnitude and timing of nodal and myelin dynamics correlate with improvement of behavioral performance during motor learning. Thus, learning-induced and circuit-specific myelination changes may contribute to information encoding in neural circuits during motor learning.
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Affiliation(s)
- Clara M Bacmeister
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
- Neuroscience IDP Program, Stanford University School of Medicine, Stanford, CA, USA
| | - Rongchen Huang
- Department of Neurosurgery, University of Colorado School of Medicine, Aurora, CO, USA
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Lindsay A Osso
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Michael A Thornton
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Lauren Conant
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Anthony R Chavez
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Alon Poleg-Polsky
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Ethan G Hughes
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA.
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9
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Auer F, Schoppik D. The Larval Zebrafish Vestibular System Is a Promising Model to Understand the Role of Myelin in Neural Circuits. Front Neurosci 2022; 16:904765. [PMID: 35600621 PMCID: PMC9122096 DOI: 10.3389/fnins.2022.904765] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 04/11/2022] [Indexed: 12/27/2022] Open
Abstract
Myelin is classically known for its role in facilitating nerve conduction. However, recent work casts myelin as a key player in both proper neuronal circuit development and function. With this expanding role comes a demand for new approaches to characterize and perturb myelin in the context of tractable neural circuits as they mature. Here we argue that the simplicity, strong conservation, and clinical relevance of the vestibular system offer a way forward. Further, the tractability of the larval zebrafish affords a uniquely powerful means to test open hypotheses of myelin's role in normal development and disordered vestibular circuits. We end by identifying key open questions in myelin neurobiology that the zebrafish vestibular system is particularly well-suited to address.
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Affiliation(s)
| | - David Schoppik
- Departments of Otolaryngology, Neuroscience & Physiology, Neuroscience Institute, New York University Grossman School of Medicine, New York, NY, United States
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10
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Xiao Y, Petrucco L, Hoodless LJ, Portugues R, Czopka T. Oligodendrocyte precursor cells sculpt the visual system by regulating axonal remodeling. Nat Neurosci 2022; 25:280-284. [PMID: 35241802 PMCID: PMC8904260 DOI: 10.1038/s41593-022-01023-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 01/25/2022] [Indexed: 12/29/2022]
Abstract
Many oligodendrocyte precursor cells (OPCs) do not differentiate to form myelin, suggesting additional roles of this cell population. The zebrafish optic tectum contains OPCs in regions devoid of myelin. Elimination of these OPCs impaired precise control of retinal ganglion cell axon arbor size during formation and maturation of retinotectal connectivity and degraded functional processing of visual stimuli. Therefore, OPCs fine-tune neural circuits independently of their canonical role to make myelin.
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Affiliation(s)
- Yan Xiao
- Institute of Neuronal Cell Biology, Technical University of Munich, Munich, Germany
| | - Luigi Petrucco
- Max Planck Institute of Neurobiology, Sensorimotor Control Research Group, Martinsried, Germany
- Institute of Neuroscience, Technical University of Munich, Munich, Germany
| | - Laura J Hoodless
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Ruben Portugues
- Max Planck Institute of Neurobiology, Sensorimotor Control Research Group, Martinsried, Germany
- Institute of Neuroscience, Technical University of Munich, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Tim Czopka
- Institute of Neuronal Cell Biology, Technical University of Munich, Munich, Germany.
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK.
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.
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11
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Vagionitis S, Auer F, Xiao Y, Almeida RG, Lyons DA, Czopka T. Clusters of neuronal neurofascin prefigure the position of a subset of nodes of Ranvier along individual central nervous system axons in vivo. Cell Rep 2022; 38:110366. [PMID: 35172135 PMCID: PMC8864464 DOI: 10.1016/j.celrep.2022.110366] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 07/08/2021] [Accepted: 01/20/2022] [Indexed: 12/23/2022] Open
Abstract
The spacing of nodes of Ranvier crucially affects conduction properties along myelinated axons. It is assumed that node position is primarily driven by growing myelin sheaths. Here, we reveal an additional mechanism of node positioning that is driven by the axon. Through longitudinal live imaging of node formation dynamics in the zebrafish central nervous system, we show that stable clusters of the cell adhesion molecule neurofascin a can accumulate at specific sites along axons prior to myelination. While some of these clusters are pushed into future node position by extending myelin sheaths, others are not and thus prefigure the position of where a mature node forms. Animals that lack full-length neurofascin a show increased internodal distances and less regular nodal spacing along single axons. Together, our data reveal the existence of an axonal mechanism to position nodes of Ranvier that does not depend on regulation by myelin sheath growth. Stable clusters of neuronal neurofascin can form along axons prior to myelination Some clusters are pushed in place by developing myelin sheaths Other clusters restrict sheath growth and thus prefigure node position Animals lacking axonal neurofascin have longer and less regular internodal spacing
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Affiliation(s)
- Stavros Vagionitis
- Institute of Neuronal Cell Biology, Technical University of Munich, 80802 Munich, Germany
| | - Franziska Auer
- Institute of Neuronal Cell Biology, Technical University of Munich, 80802 Munich, Germany
| | - Yan Xiao
- Institute of Neuronal Cell Biology, Technical University of Munich, 80802 Munich, Germany
| | - Rafael G Almeida
- Centre for Discovery Brain Sciences, University of Edinburgh, EH16 4SB Edinburgh, UK
| | - David A Lyons
- Centre for Discovery Brain Sciences, University of Edinburgh, EH16 4SB Edinburgh, UK
| | - Tim Czopka
- Institute of Neuronal Cell Biology, Technical University of Munich, 80802 Munich, Germany; Munich Cluster of Systems Neurology (SyNergy), 81377 Munich, Germany; Centre for Clinical Brain Sciences, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, EH16 4SB Edinburgh, UK.
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12
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New oligodendrocytes exhibit more abundant and accurate myelin regeneration than those that survive demyelination. Nat Neurosci 2022; 25:415-420. [PMID: 35165460 PMCID: PMC7612594 DOI: 10.1038/s41593-021-01009-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 12/22/2021] [Indexed: 12/27/2022]
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13
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The oligodendrocyte-enriched orphan G protein-coupled receptor Gpr62 is dispensable for central nervous system myelination. Neural Dev 2021; 16:6. [PMID: 34844642 PMCID: PMC8630896 DOI: 10.1186/s13064-021-00156-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 11/15/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Myelination is a highly regulated process in the vertebrate central nervous system (CNS) whereby oligodendrocytes wrap axons with multiple layers of insulating myelin in order to allow rapid electrical conduction. Establishing the proper pattern of myelin in neural circuits requires communicative axo-glial interactions, however, the molecular interactions that occur between oligodendrocytes and axons during developmental myelination and myelin maintenance remain to be fully elucidated. Our previous work identified G protein-coupled receptor 62 (Gpr62), an uncharacterized orphan g-protein coupled receptor, as being selectively expressed by mature oligodendrocytes within the CNS, suggesting a potential role in myelination or axoglial interactions. However, no studies to date have assessed the functional requirement for Gpr62 in oligodendrocyte development or CNS myelination. METHODS To address this, we generated a knockout mouse strain lacking the Gpr62 gene. We assessed CNS myelination during both postnatal development and adulthood using immunohistochemistry, electron microscopy and western blot. In addition, we utilized AAV-mediated expression of a tagged Gpr62 in oligodendrocytes to determine the subcellular localization of the protein in vivo. RESULTS We find that virally expressed Gpr62 protein is selectively expressed on the adaxonal myelin layer, suggestive of a potential role for Gpr62 in axo-myelinic signaling. Nevertheless, Gpr62 knockout mice display normal oligodendrocyte numbers and apparently normal myelination within the CNS during both postnatal development and adulthood. CONCLUSIONS We conclude that in spite of being well-placed to mediate neuronal-oligodendrocyte communications, Gpr62 is overall dispensable for CNS myelination.
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14
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Neely SA, Lyons DA. Insights Into Central Nervous System Glial Cell Formation and Function From Zebrafish. Front Cell Dev Biol 2021; 9:754606. [PMID: 34912801 PMCID: PMC8666443 DOI: 10.3389/fcell.2021.754606] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/05/2021] [Indexed: 12/23/2022] Open
Abstract
The term glia describes a heterogenous collection of distinct cell types that make up a large proportion of our nervous system. Although once considered the glue of the nervous system, the study of glial cells has evolved significantly in recent years, with a large body of literature now highlighting their complex and diverse roles in development and throughout life. This progress is due, in part, to advances in animal models in which the molecular and cellular mechanisms of glial cell development and function as well as neuron-glial cell interactions can be directly studied in vivo in real time, in intact neural circuits. In this review we highlight the instrumental role that zebrafish have played as a vertebrate model system for the study of glial cells, and discuss how the experimental advantages of the zebrafish lend themselves to investigate glial cell interactions and diversity. We focus in particular on recent studies that have provided insight into the formation and function of the major glial cell types in the central nervous system in zebrafish.
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Affiliation(s)
- Sarah A. Neely
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - David A. Lyons
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
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15
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Kang M, Yao Y. Laminin regulates oligodendrocyte development and myelination. Glia 2021; 70:414-429. [PMID: 34773273 DOI: 10.1002/glia.24117] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 10/26/2021] [Accepted: 10/29/2021] [Indexed: 11/08/2022]
Abstract
Oligodendrocytes are the cells that myelinate axons and provide trophic support to neurons in the CNS. Their dysfunction has been associated with a group of disorders known as demyelinating diseases, such as multiple sclerosis. Oligodendrocytes are derived from oligodendrocyte precursor cells, which differentiate into premyelinating oligodendrocytes and eventually mature oligodendrocytes. The development and function of oligodendrocytes are tightly regulated by a variety of molecules, including laminin, a major protein of the extracellular matrix. Accumulating evidence suggests that laminin actively regulates every aspect of oligodendrocyte biology, including survival, migration, proliferation, differentiation, and myelination. How can laminin exert such diverse functions in oligodendrocytes? It is speculated that the distinct laminin isoforms, laminin receptors, and/or key signaling molecules expressed in oligodendrocytes at different developmental stages are the reasons. Understanding molecular targets and signaling pathways unique to each aspect of oligodendrocyte biology will enable more accurate manipulation of oligodendrocyte development and function, which may have implications in the therapies of demyelinating diseases. Here in this review, we first introduce oligodendrocyte biology, followed by the expression of laminin and laminin receptors in oligodendrocytes and other CNS cells. Next, the functions of laminin in oligodendrocyte biology, including survival, migration, proliferation, differentiation, and myelination, are discussed in detail. Last, key questions and challenges in the field are discussed. By providing a comprehensive review on laminin's roles in OL lineage cells, we hope to stimulate novel hypotheses and encourage new research in the field.
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Affiliation(s)
- Minkyung Kang
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Yao Yao
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
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16
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Madden ME, Suminaite D, Ortiz E, Early JJ, Koudelka S, Livesey MR, Bianco IH, Granato M, Lyons DA. CNS Hypomyelination Disrupts Axonal Conduction and Behavior in Larval Zebrafish. J Neurosci 2021; 41:9099-9111. [PMID: 34544838 PMCID: PMC8570833 DOI: 10.1523/jneurosci.0842-21.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 08/11/2021] [Accepted: 08/16/2021] [Indexed: 11/21/2022] Open
Abstract
Myelination is essential for central nervous system (CNS) formation, health and function. As a model organism, larval zebrafish have been extensively employed to investigate the molecular and cellular basis of CNS myelination, because of their genetic tractability and suitability for non-invasive live cell imaging. However, it has not been assessed to what extent CNS myelination affects neural circuit function in zebrafish larvae, prohibiting the integration of molecular and cellular analyses of myelination with concomitant network maturation. To test whether larval zebrafish might serve as a suitable platform with which to study the effects of CNS myelination and its dysregulation on circuit function, we generated zebrafish myelin regulatory factor (myrf) mutants with CNS-specific hypomyelination and investigated how this affected their axonal conduction properties and behavior. We found that myrf mutant larvae exhibited increased latency to perform startle responses following defined acoustic stimuli. Furthermore, we found that hypomyelinated animals often selected an impaired response to acoustic stimuli, exhibiting a bias toward reorientation behavior instead of the stimulus-appropriate startle response. To begin to study how myelination affected the underlying circuitry, we established electrophysiological protocols to assess various conduction properties along single axons. We found that the hypomyelinated myrf mutants exhibited reduced action potential conduction velocity and an impaired ability to sustain high-frequency action potential firing. This study indicates that larval zebrafish can be used to bridge molecular and cellular investigation of CNS myelination with multiscale assessment of neural circuit function.SIGNIFICANCE STATEMENT Myelination of CNS axons is essential for their health and function, and it is now clear that myelination is a dynamic life-long process subject to modulation by neuronal activity. However, it remains unclear precisely how changes to myelination affects animal behavior and underlying action potential conduction along axons in intact neural circuits. In recent years, zebrafish have been employed to study cellular and molecular mechanisms of myelination, because of their relatively simple, optically transparent, experimentally tractable vertebrate nervous system. Here we find that changes to myelination alter the behavior of young zebrafish and action potential conduction along individual axons, providing a platform to integrate molecular, cellular, and circuit level analyses of myelination using this model.
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Affiliation(s)
- M E Madden
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, United Kingdom
| | - D Suminaite
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, United Kingdom
| | - E Ortiz
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - J J Early
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, United Kingdom
| | - S Koudelka
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, United Kingdom
| | - M R Livesey
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, United Kingdom
- Sheffield Institute for Translational Neuroscience, Department of Neuroscience, The University of Sheffield, Sheffield S10 2HQ, United Kingdom
| | - I H Bianco
- Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom
| | - M Granato
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - D A Lyons
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, United Kingdom
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17
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Periods of synchronized myelin changes shape brain function and plasticity. Nat Neurosci 2021; 24:1508-1521. [PMID: 34711959 DOI: 10.1038/s41593-021-00917-2] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 07/30/2021] [Indexed: 12/11/2022]
Abstract
Myelin, a lipid membrane that wraps axons, enabling fast neurotransmission and metabolic support to axons, is conventionally thought of as a static structure that is set early in development. However, recent evidence indicates that in the central nervous system (CNS), myelination is a protracted and plastic process, ongoing throughout adulthood. Importantly, myelin is emerging as a potential modulator of neuronal networks, and evidence from human studies has highlighted myelin as a major player in shaping human behavior and learning. Here we review how myelin changes throughout life and with learning. We discuss potential mechanisms of myelination at different life stages, explore whether myelin plasticity provides the regenerative potential of the CNS white matter, and question whether changes in myelin may underlie neurological disorders.
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18
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Ali MF, Latimer AJ, Wang Y, Hogenmiller L, Fontenas L, Isabella AJ, Moens CB, Yu G, Kucenas S. Met is required for oligodendrocyte progenitor cell migration in Danio rerio. G3 (BETHESDA, MD.) 2021; 11:jkab265. [PMID: 34568921 PMCID: PMC8473979 DOI: 10.1093/g3journal/jkab265] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 07/22/2021] [Indexed: 11/13/2022]
Abstract
During vertebrate central nervous system development, most oligodendrocyte progenitor cells (OPCs) are specified in the ventral spinal cord and must migrate throughout the neural tube until they become evenly distributed, occupying non-overlapping domains. While this process of developmental OPC migration is well characterized, the nature of the molecular mediators that govern it remain largely unknown. Here, using zebrafish as a model, we demonstrate that Met signaling is required for initial developmental migration of OPCs, and, using cell-specific knock-down of Met signaling, show that Met acts cell-autonomously in OPCs. Taken together, these findings demonstrate in vivo, the role of Met signaling in OPC migration and provide new insight into how OPC migration is regulated during development.
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Affiliation(s)
- Maria F Ali
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Andrew J Latimer
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Yinxue Wang
- Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Arlington, VA 22203, USA
| | - Leah Hogenmiller
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Laura Fontenas
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Adam J Isabella
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Cecilia B Moens
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Guoqiang Yu
- Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Arlington, VA 22203, USA
| | - Sarah Kucenas
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
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19
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Sams E. Oligodendrocytes in the aging brain. Neuronal Signal 2021; 5:NS20210008. [PMID: 34290887 PMCID: PMC8264650 DOI: 10.1042/ns20210008] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 05/25/2021] [Accepted: 05/26/2021] [Indexed: 12/22/2022] Open
Abstract
More than half of the human brain volume is made up of white matter: regions where axons are coated in myelin, which primarily functions to increase the conduction speed of axon potentials. White matter volume significantly decreases with age, correlating with cognitive decline. Much research in the field of non-pathological brain aging mechanisms has taken a neuron-centric approach, with relatively little attention paid to other neural cells. This review discusses white matter changes, with focus on oligodendrocyte lineage cells and their ability to produce and maintain myelin to support normal brain homoeostasis. Improved understanding of intrinsic cellular changes, general senescence mechanisms, intercellular interactions and alterations in extracellular environment which occur with aging and impact oligodendrocyte cells is paramount. This may lead to strategies to support oligodendrocytes in aging, for example by supporting myelin synthesis, protecting against oxidative stress and promoting the rejuvenation of the intrinsic regenerative potential of progenitor cells. Ultimately, this will enable the protection of white matter integrity thus protecting cognitive function into the later years of life.
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Affiliation(s)
- Eleanor Catherine Sams
- Blizard Institute, Barts and The London School of Medicine and Dentistry Centre for Neuroscience, Surgery and Trauma, Blizard Institute, 4 Newark Street, Whitechapel E1 2AT, London
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20
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Franklin RJM, Frisén J, Lyons DA. Revisiting remyelination: Towards a consensus on the regeneration of CNS myelin. Semin Cell Dev Biol 2021; 116:3-9. [PMID: 33082115 DOI: 10.1016/j.semcdb.2020.09.009] [Citation(s) in RCA: 77] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 09/18/2020] [Accepted: 09/22/2020] [Indexed: 12/16/2022]
Abstract
The biology of CNS remyelination has attracted considerable interest in recent years because of its translational potential to yield regenerative therapies for the treatment of chronic and progressive demyelinating diseases such as multiple sclerosis (MS). Critical to devising myelin regenerative therapies is a detailed understanding of how remyelination occurs. The accepted dogma, based on animal studies, has been that the myelin sheaths of remyelination are made by oligodendrocytes newly generated from adult oligodendrocyte progenitor cells in a classical regenerative process of progenitor migration, proliferation and differentiation. However, recent human and a growing number of animal studies have revealed a second mode of remyelination in which mature oligodendrocytes surviving within an area of demyelination are able to regenerate new myelin sheaths. This discovery, while opening up new opportunities for therapeutic remyelination, has also raised the question of whether there are fundamental differences in myelin regeneration between humans and some of the species in which experimental remyelination studies are conducted. Here we review how this second mode of remyelination can be integrated into a wider and revised framework for understanding remyelination in which apparent species differences can be reconciled but that also raises important questions for future research.
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Affiliation(s)
- Robin J M Franklin
- Wellcome-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, United Kingdom.
| | - Jonas Frisén
- Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden.
| | - David A Lyons
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom.
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21
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Pease-Raissi SE, Chan JR. Building a (w)rapport between neurons and oligodendroglia: Reciprocal interactions underlying adaptive myelination. Neuron 2021; 109:1258-1273. [PMID: 33621477 PMCID: PMC8068592 DOI: 10.1016/j.neuron.2021.02.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/12/2021] [Accepted: 01/29/2021] [Indexed: 12/27/2022]
Abstract
Myelin, multilayered lipid-rich membrane extensions formed by oligodendrocytes around neuronal axons, is essential for fast and efficient action potential propagation in the central nervous system. Initially thought to be a static and immutable process, myelination is now appreciated to be a dynamic process capable of responding to and modulating neuronal function throughout life. While the importance of this type of plasticity, called adaptive myelination, is now well accepted, we are only beginning to understand the underlying cellular and molecular mechanisms by which neurons communicate experience-driven circuit activation to oligodendroglia and precisely how changes in oligodendrocytes and their myelin refine neuronal function. Here, we review recent findings addressing this reciprocal relationship in which neurons alter oligodendroglial form and oligodendrocytes conversely modulate neuronal function.
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Affiliation(s)
- Sarah E Pease-Raissi
- Weill Institute for Neuroscience, Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA.
| | - Jonah R Chan
- Weill Institute for Neuroscience, Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA.
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22
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Nonaka M, Taylor WW, Bukalo O, Tucker LB, Fu AH, Kim Y, McCabe JT, Holmes A. Behavioral and Myelin-Related Abnormalities after Blast-Induced Mild Traumatic Brain Injury in Mice. J Neurotrauma 2021; 38:1551-1571. [PMID: 33605175 DOI: 10.1089/neu.2020.7254] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In civilian and military settings, mild traumatic brain injury (mTBI) is a common consequence of impacts to the head, sudden blows to the body, and exposure to high-energy atmospheric shockwaves from blast. In some cases, mTBI from blast exposure results in long-term emotional and cognitive deficits and an elevated risk for certain neuropsychiatric diseases. Here, we tested the effects of mTBI on various forms of auditory-cued fear learning and other measures of cognition in male C57BL/6J mice after single or repeated blast exposure (blast TBI; bTBI). bTBI produced an abnormality in the temporal organization of cue-induced freezing behavior in a conditioned trace fear test. Spatial working memory, evaluated by the Y-maze task performance, was also deleteriously affected by bTBI. Reverse-transcription quantitative real-time polymerase chain reaction (RT-qPCR) analysis for glial markers indicated an alteration in the expression of myelin-related genes in the hippocampus and corpus callosum 1-8 weeks after bTBI. Immunohistochemical and ultrastructural analyses detected bTBI-related myelin and axonal damage in the hippocampus and corpus callosum. Together, these data suggest a possible link between blast-induced mTBI, myelin/axonal injury, and cognitive dysfunction.
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Affiliation(s)
- Mio Nonaka
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health (NIH), Rockville, Maryland, USA
| | - William W Taylor
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health (NIH), Rockville, Maryland, USA
| | - Olena Bukalo
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health (NIH), Rockville, Maryland, USA
| | - Laura B Tucker
- Department of Anatomy, Physiology and Genetics, Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,Preclinical Studies Core, Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Amanda H Fu
- Department of Anatomy, Physiology and Genetics, Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,Preclinical Studies Core, Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Yeonho Kim
- Department of Anatomy, Physiology and Genetics, Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,Preclinical Studies Core, Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Joseph T McCabe
- Department of Anatomy, Physiology and Genetics, Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,Preclinical Studies Core, Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Andrew Holmes
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health (NIH), Rockville, Maryland, USA
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23
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Wang M, Kleele T, Xiao Y, Plucinska G, Avramopoulos P, Engelhardt S, Schwab MH, Kneussel M, Czopka T, Sherman DL, Brophy PJ, Misgeld T, Brill MS. Completion of neuronal remodeling prompts myelination along developing motor axon branches. J Cell Biol 2021; 220:e201911114. [PMID: 33538762 PMCID: PMC7868780 DOI: 10.1083/jcb.201911114] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 11/20/2020] [Accepted: 01/04/2021] [Indexed: 12/20/2022] Open
Abstract
Neuronal remodeling and myelination are two fundamental processes during neurodevelopment. How they influence each other remains largely unknown, even though their coordinated execution is critical for circuit function and often disrupted in neuropsychiatric disorders. It is unclear whether myelination stabilizes axon branches during remodeling or whether ongoing remodeling delays myelination. By modulating synaptic transmission, cytoskeletal dynamics, and axonal transport in mouse motor axons, we show that local axon remodeling delays myelination onset and node formation. Conversely, glial differentiation does not determine the outcome of axon remodeling. Delayed myelination is not due to a limited supply of structural components of the axon-glial unit but rather is triggered by increased transport of signaling factors that initiate myelination, such as neuregulin. Further, transport of promyelinating signals is regulated via local cytoskeletal maturation related to activity-dependent competition. Our study reveals an axon branch-specific fine-tuning mechanism that locally coordinates axon remodeling and myelination.
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Affiliation(s)
- Mengzhe Wang
- Institute of Neuronal Cell Biology, Technische Universität München, Munich, Germany
| | - Tatjana Kleele
- Institute of Neuronal Cell Biology, Technische Universität München, Munich, Germany
| | - Yan Xiao
- Institute of Neuronal Cell Biology, Technische Universität München, Munich, Germany
| | - Gabriela Plucinska
- Institute of Neuronal Cell Biology, Technische Universität München, Munich, Germany
| | - Petros Avramopoulos
- Institute of Pharmacology and Toxicology, Technische Universität München, Munich, Germany
- German Center for Cardiovascular Research (DZHK), partner site Munich Heart Alliance, Munich, Germany
| | - Stefan Engelhardt
- Institute of Pharmacology and Toxicology, Technische Universität München, Munich, Germany
- German Center for Cardiovascular Research (DZHK), partner site Munich Heart Alliance, Munich, Germany
| | - Markus H. Schwab
- Department of Cellular Neurophysiology, Hannover Medical School, Hannover, Germany
| | - Matthias Kneussel
- University Medical Center Hamburg-Eppendorf, Center for Molecular Neurobiology (ZMNH), Institute for Molecular Neurogenetics, Hamburg, Germany
| | - Tim Czopka
- Institute of Neuronal Cell Biology, Technische Universität München, Munich, Germany
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
- Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
| | - Diane L. Sherman
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Peter J. Brophy
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Thomas Misgeld
- Institute of Neuronal Cell Biology, Technische Universität München, Munich, Germany
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
| | - Monika S. Brill
- Institute of Neuronal Cell Biology, Technische Universität München, Munich, Germany
- Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
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24
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Mazuir E, Fricker D, Sol-Foulon N. Neuron-Oligodendrocyte Communication in Myelination of Cortical GABAergic Cells. Life (Basel) 2021; 11:216. [PMID: 33803153 PMCID: PMC7999565 DOI: 10.3390/life11030216] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/01/2021] [Accepted: 03/04/2021] [Indexed: 11/17/2022] Open
Abstract
Axonal myelination by oligodendrocytes increases the speed and reliability of action potential propagation, and so plays a pivotal role in cortical information processing. The extent and profile of myelination vary between different cortical layers and groups of neurons. Two subtypes of cortical GABAergic neurons are myelinated: fast-spiking parvalbumin-expressing cells and somatostatin-containing cells. The expression of pre-nodes on the axon of these inhibitory cells before myelination illuminates communication between oligodendrocytes and neurons. We explore the consequences of myelination for action potential propagation, for patterns of neuronal connectivity and for the expression of behavioral plasticity.
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Affiliation(s)
- Elisa Mazuir
- Inserm, CNRS, Paris Brain Institute, ICM, Sorbonne University, Pitié-Salpêtrière Hospital, F-75013 Paris, France
| | - Desdemona Fricker
- CNRS UMR 8002, Integrative Neuroscience and Cognition Center, Université de Paris, F-75006 Paris, France
| | - Nathalie Sol-Foulon
- Inserm, CNRS, Paris Brain Institute, ICM, Sorbonne University, Pitié-Salpêtrière Hospital, F-75013 Paris, France
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25
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Yang SM, Michel K, Jokhi V, Nedivi E, Arlotta P. Neuron class-specific responses govern adaptive myelin remodeling in the neocortex. Science 2021; 370:370/6523/eabd2109. [PMID: 33335032 DOI: 10.1126/science.abd2109] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 10/26/2020] [Indexed: 12/23/2022]
Abstract
Myelin plasticity is critical for neurological function, including learning and memory. However, it is unknown whether this plasticity reflects uniform changes across all neuronal subtypes, or whether myelin dynamics vary between neuronal classes to enable fine-tuning of adaptive circuit responses. We performed in vivo two-photon imaging of myelin sheaths along single axons of excitatory callosal neurons and inhibitory parvalbumin-expressing interneurons in adult mouse visual cortex. We found that both neuron types show homeostatic myelin remodeling under normal vision. However, monocular deprivation results in adaptive myelin remodeling only in parvalbumin-expressing interneurons. An initial increase in elongation of myelin segments is followed by contraction of a separate cohort of segments. This data indicates that distinct classes of neurons individualize remodeling of their myelination profiles to diversify circuit tuning in response to sensory experience.
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Affiliation(s)
- Sung Min Yang
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA
| | - Katrin Michel
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Vahbiz Jokhi
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA
| | - Elly Nedivi
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. .,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Paola Arlotta
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA. .,Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
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26
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Cullen CL, Pepper RE, Clutterbuck MT, Pitman KA, Oorschot V, Auderset L, Tang AD, Ramm G, Emery B, Rodger J, Jolivet RB, Young KM. Periaxonal and nodal plasticities modulate action potential conduction in the adult mouse brain. Cell Rep 2021; 34:108641. [PMID: 33472075 DOI: 10.1016/j.celrep.2020.108641] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 11/18/2020] [Accepted: 12/21/2020] [Indexed: 12/25/2022] Open
Abstract
Central nervous system myelination increases action potential conduction velocity. However, it is unclear how myelination is coordinated to ensure the temporally precise arrival of action potentials and facilitate information processing within cortical and associative circuits. Here, we show that myelin sheaths, supported by mature oligodendrocytes, remain plastic in the adult mouse brain and undergo subtle structural modifications to influence action potential conduction velocity. Repetitive transcranial magnetic stimulation and spatial learning, two stimuli that modify neuronal activity, alter the length of the nodes of Ranvier and the size of the periaxonal space within active brain regions. This change in the axon-glial configuration is independent of oligodendrogenesis and robustly alters action potential conduction velocity. Because aptitude in the spatial learning task was found to correlate with action potential conduction velocity in the fimbria-fornix pathway, modifying the axon-glial configuration may be a mechanism that facilitates learning in the adult mouse brain.
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Affiliation(s)
- Carlie L Cullen
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS 7000, Australia
| | - Renee E Pepper
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS 7000, Australia
| | | | - Kimberley A Pitman
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS 7000, Australia
| | - Viola Oorschot
- Ramaciotti Centre for Cryo-Electron Microscopy, Monash University, Melbourne, VIC 3800, Australia
| | - Loic Auderset
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS 7000, Australia
| | - Alexander D Tang
- Experimental and Regenerative Neuroscience, School of Biological Sciences, University of Western Australia, Perth, WA 6009, Australia
| | - Georg Ramm
- Ramaciotti Centre for Cryo-Electron Microscopy, Monash University, Melbourne, VIC 3800, Australia
| | - Ben Emery
- Jungers Center for Neurosciences Research, Department of Neurology, Oregon Health and Science University, Portland, OR 97239-3098, USA
| | - Jennifer Rodger
- Experimental and Regenerative Neuroscience, School of Biological Sciences, University of Western Australia, Perth, WA 6009, Australia; Perron Institute for Neurological and Translational Research, Perth, WA 6009, Australia
| | - Renaud B Jolivet
- Département de Physique Nucléaire et Corpusculaire, University of Geneva, 1211 Geneva 4, Switzerland
| | - Kaylene M Young
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS 7000, Australia.
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27
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Cunha MI, Su M, Cantuti-Castelvetri L, Müller SA, Schifferer M, Djannatian M, Alexopoulos I, van der Meer F, Winkler A, van Ham TJ, Schmid B, Lichtenthaler SF, Stadelmann C, Simons M. Pro-inflammatory activation following demyelination is required for myelin clearance and oligodendrogenesis. J Exp Med 2020; 217:133824. [PMID: 32078678 PMCID: PMC7201919 DOI: 10.1084/jem.20191390] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 11/22/2019] [Accepted: 01/17/2020] [Indexed: 12/19/2022] Open
Abstract
Remyelination requires innate immune system function, but how exactly microglia and macrophages clear myelin debris after injury and tailor a specific regenerative response is unclear. Here, we asked whether pro-inflammatory microglial/macrophage activation is required for this process. We established a novel toxin-based spinal cord model of de- and remyelination in zebrafish and showed that pro-inflammatory NF-κB–dependent activation in phagocytes occurs rapidly after myelin injury. We found that the pro-inflammatory response depends on myeloid differentiation primary response 88 (MyD88). MyD88-deficient mice and zebrafish were not only impaired in the degradation of myelin debris, but also in initiating the generation of new oligodendrocytes for myelin repair. We identified reduced generation of TNF-α in lesions of MyD88-deficient animals, a pro-inflammatory molecule that was able to induce the generation of new premyelinating oligodendrocytes. Our study shows that pro-inflammatory phagocytic signaling is required for myelin debris degradation, for inflammation resolution, and for initiating the generation of new oligodendrocytes.
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Affiliation(s)
- Maria Inês Cunha
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany.,German Center for Neurodegenerative Diseases, Munich, Germany.,Graduate Program in Areas of Basic and Applied Biology, Abel Salazar Biomedical Sciences Institute, University of Porto, Porto, Portugal
| | - Minhui Su
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany.,German Center for Neurodegenerative Diseases, Munich, Germany
| | - Ludovico Cantuti-Castelvetri
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany.,German Center for Neurodegenerative Diseases, Munich, Germany
| | | | - Martina Schifferer
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany.,German Center for Neurodegenerative Diseases, Munich, Germany
| | - Minou Djannatian
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany.,German Center for Neurodegenerative Diseases, Munich, Germany
| | - Ioannis Alexopoulos
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany.,German Center for Neurodegenerative Diseases, Munich, Germany
| | - Franziska van der Meer
- Department of Neuropathology, University of Göttingen Medical Center, Göttingen, Germany
| | - Anne Winkler
- Department of Neuropathology, University of Göttingen Medical Center, Göttingen, Germany
| | - Tjakko J van Ham
- Department of Clinical Genetics, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Bettina Schmid
- German Center for Neurodegenerative Diseases, Munich, Germany
| | - Stefan F Lichtenthaler
- German Center for Neurodegenerative Diseases, Munich, Germany.,Munich Cluster of Systems Neurology (SyNergy), Munich, Germany.,Neuroproteomics, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Christine Stadelmann
- Department of Neuropathology, University of Göttingen Medical Center, Göttingen, Germany
| | - Mikael Simons
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany.,German Center for Neurodegenerative Diseases, Munich, Germany.,Munich Cluster of Systems Neurology (SyNergy), Munich, Germany.,Max Planck Institute of Experimental Medicine, Göttingen, Germany
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28
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Tsata V, Kroehne V, Wehner D, Rost F, Lange C, Hoppe C, Kurth T, Reinhardt S, Petzold A, Dahl A, Loeffler M, Reimer MM, Brand M. Reactive oligodendrocyte progenitor cells (re-)myelinate the regenerating zebrafish spinal cord. Development 2020; 147:dev193946. [PMID: 33158923 DOI: 10.1242/dev.193946] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 10/28/2020] [Indexed: 12/11/2022]
Abstract
Spinal cord injury (SCI) results in loss of neurons, oligodendrocytes and myelin sheaths, all of which are not efficiently restored. The scarcity of oligodendrocytes in the lesion site impairs re-myelination of spared fibres, which leaves axons denuded, impedes signal transduction and contributes to permanent functional deficits. In contrast to mammals, zebrafish can functionally regenerate the spinal cord. Yet, little is known about oligodendroglial lineage biology and re-myelination capacity after SCI in a regeneration-permissive context. Here, we report that, in adult zebrafish, SCI results in axonal, oligodendrocyte and myelin sheath loss. We find that OPCs, the oligodendrocyte progenitor cells, survive the injury, enter a reactive state, proliferate and differentiate into oligodendrocytes. Concomitantly, the oligodendrocyte population is re-established to pre-injury levels within 2 weeks. Transcriptional profiling revealed that reactive OPCs upregulate the expression of several myelination-related genes. Interestingly, global reduction of axonal tracts and partial re-myelination, relative to pre-injury levels, persist at later stages of regeneration, yet are sufficient for functional recovery. Taken together, these findings imply that, in the zebrafish spinal cord, OPCs replace lost oligodendrocytes and, thus, re-establish myelination during regeneration.
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Affiliation(s)
- Vasiliki Tsata
- Center for Regenerative Therapies Dresden TU Dresden (CRTD) and Cluster of Excellence, Physics of Life (PoL), TU Dresden, Dresden 01307, Germany
| | - Volker Kroehne
- Center for Regenerative Therapies Dresden TU Dresden (CRTD) and Cluster of Excellence, Physics of Life (PoL), TU Dresden, Dresden 01307, Germany
| | - Daniel Wehner
- Center for Regenerative Therapies Dresden TU Dresden (CRTD) and Cluster of Excellence, Physics of Life (PoL), TU Dresden, Dresden 01307, Germany
- Max Planck Institute for the Science of Light, Erlangen 91058, Germany
- Max-Planck-Zentrum für Physik und Medizin, Erlangen 91058, Germany
| | - Fabian Rost
- Center for Regenerative Therapies Dresden TU Dresden (CRTD) and Cluster of Excellence, Physics of Life (PoL), TU Dresden, Dresden 01307, Germany
- Center for Information Services and High Performance Computing, TU Dresden, Dresden 01062, Germany
| | - Christian Lange
- Center for Regenerative Therapies Dresden TU Dresden (CRTD) and Cluster of Excellence, Physics of Life (PoL), TU Dresden, Dresden 01307, Germany
| | - Cornelia Hoppe
- Center for Regenerative Therapies Dresden TU Dresden (CRTD) and Cluster of Excellence, Physics of Life (PoL), TU Dresden, Dresden 01307, Germany
| | - Thomas Kurth
- Center for Molecular and Cellular Bioengineering (CMCB), TU Dresden, Technology Platform, Dresden 01307, Germany
| | - Susanne Reinhardt
- Dresden Genome Center c/o Center for Regenerative Therapies TU Dresden (CRTD), TU Dresden, Dresden 01307, Germany
| | - Andreas Petzold
- Dresden Genome Center c/o Center for Regenerative Therapies TU Dresden (CRTD), TU Dresden, Dresden 01307, Germany
| | - Andreas Dahl
- Dresden Genome Center c/o Center for Regenerative Therapies TU Dresden (CRTD), TU Dresden, Dresden 01307, Germany
| | - Markus Loeffler
- Center for Advancing Electronics Dresden (cfaed)/Dresden Center for Nanoanalysis (DCN), TU Dresden, Dresden 01062, Germany
| | - Michell M Reimer
- Center for Regenerative Therapies Dresden TU Dresden (CRTD) and Cluster of Excellence, Physics of Life (PoL), TU Dresden, Dresden 01307, Germany
| | - Michael Brand
- Center for Regenerative Therapies Dresden TU Dresden (CRTD) and Cluster of Excellence, Physics of Life (PoL), TU Dresden, Dresden 01307, Germany
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29
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Abstract
The nodes of Ranvier have clustered Na+ and K+ channels necessary for rapid and efficient axonal action potential conduction. However, detailed mechanisms of channel clustering have only recently been identified: they include two independent axon-glia interactions that converge on distinct axonal cytoskeletons. Here, we discuss how glial cell adhesion molecules and the extracellular matrix molecules that bind them assemble combinations of ankyrins, spectrins and other cytoskeletal scaffolding proteins, which cluster ion channels. We present a detailed molecular model, incorporating these overlapping mechanisms, to explain how the nodes of Ranvier are assembled in both the peripheral and central nervous systems.
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30
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Snaidero N, Schifferer M, Mezydlo A, Zalc B, Kerschensteiner M, Misgeld T. Myelin replacement triggered by single-cell demyelination in mouse cortex. Nat Commun 2020; 11:4901. [PMID: 32994410 PMCID: PMC7525521 DOI: 10.1038/s41467-020-18632-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 09/02/2020] [Indexed: 12/14/2022] Open
Abstract
Myelin, rather than being a static insulator of axons, is emerging as an active participant in circuit plasticity. This requires precise regulation of oligodendrocyte numbers and myelination patterns. Here, by devising a laser ablation approach of single oligodendrocytes, followed by in vivo imaging and correlated ultrastructural reconstructions, we report that in mouse cortex demyelination as subtle as the loss of a single oligodendrocyte can trigger robust cell replacement and remyelination timed by myelin breakdown. This results in reliable reestablishment of the original myelin pattern along continuously myelinated axons, while in parallel, patchy isolated internodes emerge on previously unmyelinated axons. Therefore, in mammalian cortex, internodes along partially myelinated cortical axons are typically not reestablished, suggesting that the cues that guide patchy myelination are not preserved through cycles of de- and remyelination. In contrast, myelin sheaths forming continuous patterns show remarkable homeostatic resilience and remyelinate with single axon precision.
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Affiliation(s)
- Nicolas Snaidero
- Institute of Neuronal Cell Biology, Technische Universität München, 80802, Munich, Germany.
- German Center for Neurodegenerative Diseases (DZNE), 81377, Munich, Germany.
- Institute of Clinical Neuroimmunology, University Hospital, Ludwig-Maximilians Universität München, 81377, Munich, Germany.
- Biomedical Center (BMC), Faculty of Medicine, Ludwig-Maximilians Universität München, 82152, Martinsried, Germany.
| | - Martina Schifferer
- German Center for Neurodegenerative Diseases (DZNE), 81377, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Aleksandra Mezydlo
- Institute of Clinical Neuroimmunology, University Hospital, Ludwig-Maximilians Universität München, 81377, Munich, Germany
- Biomedical Center (BMC), Faculty of Medicine, Ludwig-Maximilians Universität München, 82152, Martinsried, Germany
| | - Bernard Zalc
- Inserm, CNRS, Institut du Cerveau, Pitié-Salpêtrière Hospital, Sorbonne Université, 75013, Paris, France
| | - Martin Kerschensteiner
- Institute of Clinical Neuroimmunology, University Hospital, Ludwig-Maximilians Universität München, 81377, Munich, Germany
- Biomedical Center (BMC), Faculty of Medicine, Ludwig-Maximilians Universität München, 82152, Martinsried, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Thomas Misgeld
- Institute of Neuronal Cell Biology, Technische Universität München, 80802, Munich, Germany
- German Center for Neurodegenerative Diseases (DZNE), 81377, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
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31
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Nelson HN, Treichel AJ, Eggum EN, Martell MR, Kaiser AJ, Trudel AG, Gronseth JR, Maas ST, Bergen S, Hines JH. Individual neuronal subtypes control initial myelin sheath growth and stabilization. Neural Dev 2020; 15:12. [PMID: 32988384 PMCID: PMC7523326 DOI: 10.1186/s13064-020-00149-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 09/17/2020] [Indexed: 01/21/2023] Open
Abstract
Background In the developing central nervous system, pre-myelinating oligodendrocytes sample candidate nerve axons by extending and retracting process extensions. Some contacts stabilize, leading to the initiation of axon wrapping, nascent myelin sheath formation, concentric wrapping and sheath elongation, and sheath stabilization or pruning by oligodendrocytes. Although axonal signals influence the overall process of myelination, the precise oligodendrocyte behaviors that require signaling from axons are not completely understood. In this study, we investigated whether oligodendrocyte behaviors during the early events of myelination are mediated by an oligodendrocyte-intrinsic myelination program or are over-ridden by axonal factors. Methods To address this, we utilized in vivo time-lapse imaging in embryonic and larval zebrafish spinal cord during the initial hours and days of axon wrapping and myelination. Transgenic reporter lines marked individual axon subtypes or oligodendrocyte membranes. Results In the larval zebrafish spinal cord, individual axon subtypes supported distinct nascent sheath growth rates and stabilization frequencies. Oligodendrocytes ensheathed individual axon subtypes at different rates during a two-day period after initial axon wrapping. When descending reticulospinal axons were ablated, local spinal axons supported a constant ensheathment rate despite the increased ratio of oligodendrocytes to target axons. Conclusion We conclude that properties of individual axon subtypes instruct oligodendrocyte behaviors during initial stages of myelination by differentially controlling nascent sheath growth and stabilization.
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Affiliation(s)
| | | | - Erin N Eggum
- Biology Department, Winona State University, Winona, MN, USA
| | | | - Amanda J Kaiser
- Biology Department, Winona State University, Winona, MN, USA
| | - Allie G Trudel
- Biology Department, Winona State University, Winona, MN, USA
| | | | - Samantha T Maas
- Biology Department, Winona State University, Winona, MN, USA
| | - Silas Bergen
- Biology Department, Winona State University, Winona, MN, USA
| | - Jacob H Hines
- Biology Department, Winona State University, Winona, MN, USA.
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32
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Lubetzki C, Sol-Foulon N, Desmazières A. Nodes of Ranvier during development and repair in the CNS. Nat Rev Neurol 2020; 16:426-439. [DOI: 10.1038/s41582-020-0375-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2020] [Indexed: 01/01/2023]
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33
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Werkman IL, Lentferink DH, Baron W. Macroglial diversity: white and grey areas and relevance to remyelination. Cell Mol Life Sci 2020; 78:143-171. [PMID: 32648004 PMCID: PMC7867526 DOI: 10.1007/s00018-020-03586-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 06/20/2020] [Accepted: 06/23/2020] [Indexed: 02/06/2023]
Abstract
Macroglia, comprising astrocytes and oligodendroglial lineage cells, have long been regarded as uniform cell types of the central nervous system (CNS). Although regional morphological differences between these cell types were initially described after their identification a century ago, these differences were largely ignored. Recently, accumulating evidence suggests that macroglial cells form distinct populations throughout the CNS, based on both functional and morphological features. Moreover, with the use of refined techniques including single-cell and single-nucleus RNA sequencing, additional evidence is emerging for regional macroglial heterogeneity at the transcriptional level. In parallel, several studies revealed the existence of regional differences in remyelination capacity between CNS grey and white matter areas, both in experimental models for successful remyelination as well as in the chronic demyelinating disease multiple sclerosis (MS). In this review, we provide an overview of the diversity in oligodendroglial lineage cells and astrocytes from the grey and white matter, as well as their interplay in health and upon demyelination and successful remyelination. In addition, we discuss the implications of regional macroglial diversity for remyelination in light of its failure in MS. Since the etiology of MS remains unknown and only disease-modifying treatments altering the immune response are available for MS, the elucidation of macroglial diversity in grey and white matter and its putative contribution to the observed difference in remyelination efficiency between these regions may open therapeutic avenues aimed at enhancing endogenous remyelination in either area.
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Affiliation(s)
- Inge L Werkman
- Department of Biomedical Sciences of Cells and Systems, Section Molecular Neurobiology, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV, Groningen, the Netherlands
- Department of Biology, University of Virginia, Charlottesville, VA, 22904, USA
| | - Dennis H Lentferink
- Department of Biomedical Sciences of Cells and Systems, Section Molecular Neurobiology, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV, Groningen, the Netherlands
| | - Wia Baron
- Department of Biomedical Sciences of Cells and Systems, Section Molecular Neurobiology, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV, Groningen, the Netherlands.
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34
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Activity-dependent myelination: A glial mechanism of oscillatory self-organization in large-scale brain networks. Proc Natl Acad Sci U S A 2020; 117:13227-13237. [PMID: 32482855 DOI: 10.1073/pnas.1916646117] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Communication and oscillatory synchrony between distributed neural populations are believed to play a key role in multiple cognitive and neural functions. These interactions are mediated by long-range myelinated axonal fiber bundles, collectively termed as white matter. While traditionally considered to be static after development, white matter properties have been shown to change in an activity-dependent way through learning and behavior-a phenomenon known as white matter plasticity. In the central nervous system, this plasticity stems from oligodendroglia, which form myelin sheaths to regulate the conduction of nerve impulses across the brain, hence critically impacting neural communication. We here shift the focus from neural to glial contribution to brain synchronization and examine the impact of adaptive, activity-dependent changes in conduction velocity on the large-scale phase synchronization of neural oscillators. Using a network model based on primate large-scale white matter neuroanatomy, our computational and mathematical results show that such plasticity endows white matter with self-organizing properties, where conduction delay statistics are autonomously adjusted to ensure efficient neural communication. Our analysis shows that this mechanism stabilizes oscillatory neural activity across a wide range of connectivity gain and frequency bands, making phase-locked states more resilient to damage as reflected by diffuse decreases in connectivity. Critically, our work suggests that adaptive myelination may be a mechanism that enables brain networks with a means of temporal self-organization, resilience, and homeostasis.
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35
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Orthmann-Murphy J, Call CL, Molina-Castro GC, Hsieh YC, Rasband MN, Calabresi PA, Bergles DE. Remyelination alters the pattern of myelin in the cerebral cortex. eLife 2020; 9:e56621. [PMID: 32459173 PMCID: PMC7292648 DOI: 10.7554/elife.56621] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 05/22/2020] [Indexed: 11/25/2022] Open
Abstract
Destruction of oligodendrocytes and myelin sheaths in cortical gray matter profoundly alters neural activity and is associated with cognitive disability in multiple sclerosis (MS). Myelin can be restored by regenerating oligodendrocytes from resident progenitors; however, it is not known whether regeneration restores the complex myelination patterns in cortical circuits. Here, we performed time lapse in vivo two photon imaging in somatosensory cortex of adult mice to define the kinetics and specificity of myelin regeneration after acute oligodendrocyte ablation. These longitudinal studies revealed that the pattern of myelination in cortex changed dramatically after regeneration, as new oligodendrocytes were formed in different locations and new sheaths were often established along axon segments previously lacking myelin. Despite the dramatic increase in axonal territory available, oligodendrogenesis was persistently impaired in deeper cortical layers that experienced higher gliosis. Repeated reorganization of myelin patterns in MS may alter circuit function and contribute to cognitive decline.
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Affiliation(s)
- Jennifer Orthmann-Murphy
- The Solomon Snyder Department of Neuroscience, Johns Hopkins UniversityBaltimoreUnited States
- Department of Neurology, Perelman School of Medicine, University of PennsylvaniaPhiladelphiaUnited States
| | - Cody L Call
- The Solomon Snyder Department of Neuroscience, Johns Hopkins UniversityBaltimoreUnited States
| | - Gian C Molina-Castro
- The Solomon Snyder Department of Neuroscience, Johns Hopkins UniversityBaltimoreUnited States
| | - Yu Chen Hsieh
- The Solomon Snyder Department of Neuroscience, Johns Hopkins UniversityBaltimoreUnited States
| | - Matthew N Rasband
- Department of Neuroscience, Baylor College of Medicine, One Baylor PlazaHoustonUnited States
| | - Peter A Calabresi
- Department of Neurology Johns Hopkins UniversityBaltimoreUnited States
| | - Dwight E Bergles
- The Solomon Snyder Department of Neuroscience, Johns Hopkins UniversityBaltimoreUnited States
- Johns Hopkins University Kavli Neuroscience Discovery InstituteBaltimoreUnited States
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36
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Sousa SC, Sousa MM. The cytoskeleton as a modulator of tension driven axon elongation. Dev Neurobiol 2020; 81:300-309. [PMID: 32302060 DOI: 10.1002/dneu.22747] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 02/11/2020] [Accepted: 04/09/2020] [Indexed: 02/07/2023]
Abstract
Throughout development, neurons are capable of integrating external and internal signals leading to the morphological changes required for neuronal polarization and axon growth. The first phase of axon elongation occurs during neuronal polarization. At this stage, membrane remodeling and cytoskeleton dynamics are crucial for the growth cone to advance and guide axon elongation. When a target is recognized, the growth cone collapses to form the presynaptic terminal. Once a synapse is established, the growth of the organism results in an increased distance between the neuronal cell bodies and their targets. In this second phase of axon elongation, growth cone-independent molecular mechanisms and cytoskeleton changes must occur to enable axon growth to accompany the increase in body size. While the field has mainly focused on growth-cone mediated axon elongation during development, tension driven axon growth remains largely unexplored. In this review, we will discuss in a critical perspective the current knowledge on the mechanisms guiding axon growth following synaptogenesis, with a particular focus on the putative role played by the axonal cytoskeleton.
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Affiliation(s)
- Sara C Sousa
- Nerve Regeneration group, Instituto de Biologia Molecular e Celular - IBMC and i3S, Instituto de Inovação e Investigação em Saúde, University of Porto, Porto, Portugal.,Doctoral Program in Molecular and Cell Biology, Instituto de Ciências Biomédicas Abel Salazar-ICBAS, University of Porto, Porto, Portugal
| | - Mónica M Sousa
- Nerve Regeneration group, Instituto de Biologia Molecular e Celular - IBMC and i3S, Instituto de Inovação e Investigação em Saúde, University of Porto, Porto, Portugal
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37
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Neurotoxicity of nanoparticles entering the brain via sensory nerve-to-brain pathways: injuries and mechanisms. Arch Toxicol 2020; 94:1479-1495. [DOI: 10.1007/s00204-020-02701-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 03/05/2020] [Indexed: 12/15/2022]
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38
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Functionally distinct subgroups of oligodendrocyte precursor cells integrate neural activity and execute myelin formation. Nat Neurosci 2020; 23:363-374. [PMID: 32066987 PMCID: PMC7292734 DOI: 10.1038/s41593-019-0581-2] [Citation(s) in RCA: 115] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 12/20/2019] [Indexed: 01/06/2023]
Abstract
Recent reports have revealed oligodendrocyte precursor cell (OPC)
heterogeneity. It remains unclear if such heterogeneity reflects different
subtypes of cells with distinct functions, or rather transiently acquired states
of cells with the same function. By integrating lineage formation of individual
OPC clones, single-cell transcriptomics, calcium imaging and neural activity
manipulation, we show that OPCs in the zebrafish spinal cord can be divided into
two functionally distinct groups. One subgroup forms elaborate networks of
processes and exhibits a high degree of calcium signalling, but infrequently
differentiates, despite contact with permissive axons. Instead, these OPCs
divide in an activity and calcium dependent manner to produce another subgroup
with higher process motility and less calcium signaling, which readily
differentiates. Our data show that OPC subgroups are functionally diverse in
responding to neurons and reveal that activity regulates proliferation of a
subset of OPCs that is distinct from the cells that generate differentiated
oligodendrocytes.
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39
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Mostajo-Radji MA, Schmitz MT, Montoya ST, Pollen AA. Reverse engineering human brain evolution using organoid models. Brain Res 2020; 1729:146582. [PMID: 31809699 PMCID: PMC7058376 DOI: 10.1016/j.brainres.2019.146582] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 11/25/2019] [Accepted: 11/29/2019] [Indexed: 02/06/2023]
Abstract
Primate brains vary dramatically in size and organization, but the genetic and developmental basis for these differences has been difficult to study due to lack of experimental models. Pluripotent stem cells and brain organoids provide a potential opportunity for comparative and functional studies of evolutionary differences, particularly during the early stages of neurogenesis. However, many challenges remain, including isolating stem cell lines from additional great ape individuals and species to capture the breadth of ape genetic diversity, improving the reproducibility of organoid models to study evolved differences in cell composition and combining multiple brain regions to capture connectivity relationships. Here, we describe strategies for identifying evolved developmental differences between humans and non-human primates and for isolating the underlying cellular and genetic mechanisms using comparative analyses, chimeric organoid culture, and genome engineering. In particular, we focus on how organoid models could ultimately be applied beyond studies of progenitor cell evolution to decode the origin of recent changes in cellular organization, connectivity patterns, myelination, synaptic development, and physiology that have been implicated in human cognition.
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Affiliation(s)
- Mohammed A Mostajo-Radji
- Department of Neurology, University of California San Francisco, San Francisco, CA 94143, USA; The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California San Francisco, San Francisco, CA 94143, USA
| | - Matthew T Schmitz
- Department of Neurology, University of California San Francisco, San Francisco, CA 94143, USA; The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California San Francisco, San Francisco, CA 94143, USA
| | - Sebastian Torres Montoya
- Health Co-creation Laboratory, Medellin General Hospital, Medellin, Antioquia, Colombia; Baskin School of Engineering, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - Alex A Pollen
- Department of Neurology, University of California San Francisco, San Francisco, CA 94143, USA; The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California San Francisco, San Francisco, CA 94143, USA.
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40
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Tian W, Czopka T, López-Schier H. Systemic loss of Sarm1 protects Schwann cells from chemotoxicity by delaying axon degeneration. Commun Biol 2020; 3:49. [PMID: 32001778 PMCID: PMC6992705 DOI: 10.1038/s42003-020-0776-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 01/09/2020] [Indexed: 12/11/2022] Open
Abstract
Protecting the nervous system from chronic effects of physical and chemical stress is a pressing clinical challenge. The obligate pro-degenerative protein Sarm1 is essential for Wallerian axon degeneration. Thus, blocking Sarm1 function is emerging as a promising neuroprotective strategy with therapeutic relevance. Yet, the conditions that will most benefit from inhibiting Sarm1 remain undefined. Here we combine genome engineering, pharmacology and high-resolution intravital videmicroscopy in zebrafish to show that genetic elimination of Sarm1 increases Schwann-cell resistance to toxicity by diverse chemotherapeutic agents after axonal injury. Synthetic degradation of Sarm1-deficient axons reversed this effect, suggesting that glioprotection is a non-autonomous effect of delayed axon degeneration. Moreover, loss of Sarm1 does not affect macrophage recruitment to nerve-wound microenvironment, injury resolution, or neural-circuit repair. These findings anticipate that interventions aimed at inhibiting Sarm1 can counter heightened glial vulnerability to chemical stressors and may be an effective strategy to reduce chronic consequences of neurotrauma.
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Affiliation(s)
- Weili Tian
- Sensory Biology & Organogenesis, Helmholtz Zentrum Munich, Munich, Germany
| | - Tim Czopka
- Institute of Neuronal Cell Biology, Technical University of Munich, Munich, Germany
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41
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Chapman TW, Hill RA. Myelin plasticity in adulthood and aging. Neurosci Lett 2019; 715:134645. [PMID: 31765728 DOI: 10.1016/j.neulet.2019.134645] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 11/06/2019] [Accepted: 11/21/2019] [Indexed: 12/31/2022]
Abstract
The central nervous system maintains the potential for molecular and cellular plasticity throughout life. This flexibility underlies fundamental features of neural circuitry including the brain's ability to sense, store, and properly adapt to everchanging external stimuli on time scales from seconds to years. Evidence for most forms of plasticity are centered around changes in neuronal structure and synaptic strength, however recent data suggests that myelinating oligodendrocytes exhibit certain forms of plasticity in the adult. This plasticity ranges from the generation of entirely new myelinating cells to more subtle changes in myelin sheath length, thickness, and distribution along axons. The extent to which these changes dynamically modify axonal function and neural circuitry and whether they are directly related to mechanisms of learning and memory remains an open question. Here we describe different forms of myelin plasticity, highlight some recent evidence for changes in myelination throughout life, and discuss how defects in these forms of plasticity could be associated with cognitive decline in aging.
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Affiliation(s)
- Timothy W Chapman
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA
| | - Robert A Hill
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA.
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42
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Klingseisen A, Ristoiu AM, Kegel L, Sherman DL, Rubio-Brotons M, Almeida RG, Koudelka S, Benito-Kwiecinski SK, Poole RJ, Brophy PJ, Lyons DA. Oligodendrocyte Neurofascin Independently Regulates Both Myelin Targeting and Sheath Growth in the CNS. Dev Cell 2019; 51:730-744.e6. [PMID: 31761670 PMCID: PMC6912162 DOI: 10.1016/j.devcel.2019.10.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 09/10/2019] [Accepted: 10/17/2019] [Indexed: 01/06/2023]
Abstract
Selection of the correct targets for myelination and regulation of myelin sheath growth are essential for central nervous system (CNS) formation and function. Through a genetic screen in zebrafish and complementary analyses in mice, we find that loss of oligodendrocyte Neurofascin leads to mistargeting of myelin to cell bodies, without affecting targeting to axons. In addition, loss of Neurofascin reduces CNS myelination by impairing myelin sheath growth. Time-lapse imaging reveals that the distinct myelinating processes of individual oligodendrocytes can engage in target selection and sheath growth at the same time and that Neurofascin concomitantly regulates targeting and growth. Disruption to Caspr, the neuronal binding partner of oligodendrocyte Neurofascin, also impairs myelin sheath growth, likely reflecting its association in an adhesion complex at the axon-glial interface with Neurofascin. Caspr does not, however, affect myelin targeting, further indicating that Neurofascin independently regulates distinct aspects of CNS myelination by individual oligodendrocytes in vivo. Single oligodendrocytes coordinate myelin targeting and growth at the same time Oligodendrocyte Neurofascin prevents myelination of cell bodies Oligodendrocyte Neurofascin promotes myelin sheath growth The neuronal binding partner of Neurofascin, Caspr, promotes myelin sheath growth
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Affiliation(s)
- Anna Klingseisen
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Ana-Maria Ristoiu
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Linde Kegel
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Diane L Sherman
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Maria Rubio-Brotons
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Rafael G Almeida
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Sigrid Koudelka
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | | | - Richard J Poole
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Peter J Brophy
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - David A Lyons
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK.
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43
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Stedehouder J, Brizee D, Slotman JA, Pascual-Garcia M, Leyrer ML, Bouwen BL, Dirven CM, Gao Z, Berson DM, Houtsmuller AB, Kushner SA. Local axonal morphology guides the topography of interneuron myelination in mouse and human neocortex. eLife 2019; 8:48615. [PMID: 31742557 PMCID: PMC6927753 DOI: 10.7554/elife.48615] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 11/18/2019] [Indexed: 12/30/2022] Open
Abstract
GABAergic fast-spiking parvalbumin-positive (PV) interneurons are frequently myelinated in the cerebral cortex. However, the factors governing the topography of cortical interneuron myelination remain incompletely understood. Here, we report that segmental myelination along neocortical interneuron axons is strongly predicted by the joint combination of interbranch distance and local axon caliber. Enlargement of PV+ interneurons increased axonal myelination, while reduced cell size led to decreased myelination. Next, we considered regular-spiking SOM+ cells, which normally have relatively shorter interbranch distances and thinner axon diameters than PV+ cells, and are rarely myelinated. Consistent with the importance of axonal morphology for guiding interneuron myelination, enlargement of SOM+ cell size dramatically increased the frequency of myelinated axonal segments. Lastly, we confirm that these findings also extend to human neocortex by quantifying interneuron axonal myelination from ex vivo surgical tissue. Together, these findings establish a predictive model of neocortical GABAergic interneuron myelination determined by local axonal morphology.
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Affiliation(s)
- Jeffrey Stedehouder
- Department of Psychiatry, Erasmus MC University Medical Center, Rotterdam, Netherlands
| | - Demi Brizee
- Department of Psychiatry, Erasmus MC University Medical Center, Rotterdam, Netherlands
| | - Johan A Slotman
- Erasmus Optical Imaging Center, Department of Pathology, Erasmus MC University Medical Center, Rotterdam, Netherlands
| | - Maria Pascual-Garcia
- Department of Psychiatry, Erasmus MC University Medical Center, Rotterdam, Netherlands
| | - Megan L Leyrer
- Department of Neuroscience, Brown University, Providence, United States
| | - Bibi Lj Bouwen
- Department of Neuroscience, Erasmus MC University Medical Center, Rotterdam, Netherlands.,Department of Neurosurgery, Erasmus MC University Medical Center, Rotterdam, Netherlands
| | - Clemens Mf Dirven
- Department of Neurosurgery, Erasmus MC University Medical Center, Rotterdam, Netherlands
| | - Zhenyu Gao
- Department of Neuroscience, Erasmus MC University Medical Center, Rotterdam, Netherlands
| | - David M Berson
- Department of Neuroscience, Brown University, Providence, United States
| | - Adriaan B Houtsmuller
- Erasmus Optical Imaging Center, Department of Pathology, Erasmus MC University Medical Center, Rotterdam, Netherlands
| | - Steven A Kushner
- Department of Psychiatry, Erasmus MC University Medical Center, Rotterdam, Netherlands
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Suminaite D, Lyons DA, Livesey MR. Myelinated axon physiology and regulation of neural circuit function. Glia 2019; 67:2050-2062. [PMID: 31233642 PMCID: PMC6772175 DOI: 10.1002/glia.23665] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 05/28/2019] [Accepted: 06/06/2019] [Indexed: 12/15/2022]
Abstract
The study of structural and functional plasticity in the central nervous system (CNS) to date has focused primarily on that of neurons and synapses. However, more recent studies implicate glial cells as key regulators of neural circuit function. Among these, the myelinating glia of the CNS, oligodendrocytes, have been shown to be responsive to extrinsic signals including neuronal activity, and in turn, tune neurophysiological function. Due to the fact that myelin fundamentally alters the conduction properties of axons, much attention has focused on how dynamic regulation of myelination might represent a form of functional plasticity. Here, we highlight recent research that indicates that it is not only myelin, but essentially all the function-regulating components of the myelinated axon that are responsive to neuronal activity. For example, the axon initial segment, nodes of Ranvier, heminodes, axonal termini, and the morphology of the axon itself all exhibit the potential to respond to neuronal activity, and in so doing might underpin specific functional outputs. We also highlight emerging evidence that the myelin sheath itself has a rich physiology capable of influencing axonal physiology. We suggest that to fully understand nervous system plasticity we need to consider the fact that myelinated axon is an integrated functional unit and adaptations that influence the entire functional unit are likely to underpin modifications to neural circuit function.
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Affiliation(s)
| | - David A. Lyons
- Centre for Discovery Brain SciencesUniversity of EdinburghEdinburghUK
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Stadelmann C, Timmler S, Barrantes-Freer A, Simons M. Myelin in the Central Nervous System: Structure, Function, and Pathology. Physiol Rev 2019; 99:1381-1431. [PMID: 31066630 DOI: 10.1152/physrev.00031.2018] [Citation(s) in RCA: 292] [Impact Index Per Article: 58.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Oligodendrocytes generate multiple layers of myelin membrane around axons of the central nervous system to enable fast and efficient nerve conduction. Until recently, saltatory nerve conduction was considered the only purpose of myelin, but it is now clear that myelin has more functions. In fact, myelinating oligodendrocytes are embedded in a vast network of interconnected glial and neuronal cells, and increasing evidence supports an active role of oligodendrocytes within this assembly, for example, by providing metabolic support to neurons, by regulating ion and water homeostasis, and by adapting to activity-dependent neuronal signals. The molecular complexity governing these interactions requires an in-depth molecular understanding of how oligodendrocytes and axons interact and how they generate, maintain, and remodel their myelin sheaths. This review deals with the biology of myelin, the expanded relationship of myelin with its underlying axons and the neighboring cells, and its disturbances in various diseases such as multiple sclerosis, acute disseminated encephalomyelitis, and neuromyelitis optica spectrum disorders. Furthermore, we will highlight how specific interactions between astrocytes, oligodendrocytes, and microglia contribute to demyelination in hereditary white matter pathologies.
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Affiliation(s)
- Christine Stadelmann
- Institute of Neuropathology, University Medical Center Göttingen , Göttingen , Germany ; Institute of Neuronal Cell Biology, Technical University Munich , Munich , Germany ; German Center for Neurodegenerative Diseases (DZNE), Munich , Germany ; Department of Neuropathology, University Medical Center Leipzig , Leipzig , Germany ; Munich Cluster of Systems Neurology (SyNergy), Munich , Germany ; and Max Planck Institute of Experimental Medicine, Göttingen , Germany
| | - Sebastian Timmler
- Institute of Neuropathology, University Medical Center Göttingen , Göttingen , Germany ; Institute of Neuronal Cell Biology, Technical University Munich , Munich , Germany ; German Center for Neurodegenerative Diseases (DZNE), Munich , Germany ; Department of Neuropathology, University Medical Center Leipzig , Leipzig , Germany ; Munich Cluster of Systems Neurology (SyNergy), Munich , Germany ; and Max Planck Institute of Experimental Medicine, Göttingen , Germany
| | - Alonso Barrantes-Freer
- Institute of Neuropathology, University Medical Center Göttingen , Göttingen , Germany ; Institute of Neuronal Cell Biology, Technical University Munich , Munich , Germany ; German Center for Neurodegenerative Diseases (DZNE), Munich , Germany ; Department of Neuropathology, University Medical Center Leipzig , Leipzig , Germany ; Munich Cluster of Systems Neurology (SyNergy), Munich , Germany ; and Max Planck Institute of Experimental Medicine, Göttingen , Germany
| | - Mikael Simons
- Institute of Neuropathology, University Medical Center Göttingen , Göttingen , Germany ; Institute of Neuronal Cell Biology, Technical University Munich , Munich , Germany ; German Center for Neurodegenerative Diseases (DZNE), Munich , Germany ; Department of Neuropathology, University Medical Center Leipzig , Leipzig , Germany ; Munich Cluster of Systems Neurology (SyNergy), Munich , Germany ; and Max Planck Institute of Experimental Medicine, Göttingen , Germany
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Abstract
Microtubules are critical for the extension of oligodendrocyte processes and myelin deposition, yet our knowledge of their microtubule biogenesis is limited. In this issue of Cell, Fu et al. (2019) identify an oligodendrocyte-enriched microtubule regulator that promotes microtubule growth from Golgi outposts and controls myelin sheath elongation, linking microtubule cytoarchitecture and myelination in the CNS.
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Affiliation(s)
- Antonina Roll-Mecak
- Cell Biology and Biophysics Unit, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, USA; Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, NIH, Bethesda, MD, USA.
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47
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Hughes AN, Appel B. Oligodendrocytes express synaptic proteins that modulate myelin sheath formation. Nat Commun 2019; 10:4125. [PMID: 31511515 PMCID: PMC6739339 DOI: 10.1038/s41467-019-12059-y] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 08/14/2019] [Indexed: 02/03/2023] Open
Abstract
Vesicular release from neurons promotes myelin sheath growth on axons. Oligodendrocytes express proteins that allow dendrites to respond to vesicular release at synapses, suggesting that axon-myelin contacts use similar communication mechanisms as synapses to form myelin sheaths. To test this, we used fusion proteins to track synaptic vesicle localization and membrane fusion in zebrafish during developmental myelination and investigated expression and localization of PSD95, a dendritic post-synaptic protein, within oligodendrocytes. Synaptic vesicles accumulate and exocytose at ensheathment sites with variable patterning and most sheaths localize PSD95 with patterning similar to exocytosis site location. Disruption of candidate PDZ-binding transsynaptic adhesion proteins in oligodendrocytes cause variable effects on sheath length and number. One candidate, Cadm1b, localizes to myelin sheaths where both PDZ binding and extracellular adhesion to axons mediate sheath growth. Our work raises the possibility that axon-glial communication contributes to myelin plasticity, providing new targets for mechanistic unraveling of developmental myelination.
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Affiliation(s)
- Alexandria N Hughes
- University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Bruce Appel
- University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, 80045, USA.
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49
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Isaacs BR, Trutti AC, Pelzer E, Tittgemeyer M, Temel Y, Forstmann BU, Keuken MC. Cortico-basal white matter alterations occurring in Parkinson's disease. PLoS One 2019; 14:e0214343. [PMID: 31425517 PMCID: PMC6699705 DOI: 10.1371/journal.pone.0214343] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 07/17/2019] [Indexed: 01/01/2023] Open
Abstract
Magnetic resonance imaging studies typically use standard anatomical atlases for identification and analyses of (patho-)physiological effects on specific brain areas; these atlases often fail to incorporate neuroanatomical alterations that may occur with both age and disease. The present study utilizes Parkinson's disease and age-specific anatomical atlases of the subthalamic nucleus for diffusion tractography, assessing tracts that run between the subthalamic nucleus and a-priori defined cortical areas known to be affected by Parkinson's disease. The results show that the strength of white matter fiber tracts appear to remain structurally unaffected by disease. Contrary to that, Fractional Anisotropy values were shown to decrease in Parkinson's disease patients for connections between the subthalamic nucleus and the pars opercularis of the inferior frontal gyrus, anterior cingulate cortex, the dorsolateral prefrontal cortex and the pre-supplementary motor, collectively involved in preparatory motor control, decision making and task monitoring. While the biological underpinnings of fractional anisotropy alterations remain elusive, they may nonetheless be used as an index of Parkinson's disease. Moreover, we find that failing to account for structural changes occurring in the subthalamic nucleus with age and disease reduce the accuracy and influence the results of tractography, highlighting the importance of using appropriate atlases for tractography.
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Affiliation(s)
- Bethany. R. Isaacs
- Integrative Model-based Cognitive Neuroscience research unit, University of Amsterdam, Amsterdam, the Netherlands
- Department of Neurosurgery, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Anne. C. Trutti
- Integrative Model-based Cognitive Neuroscience research unit, University of Amsterdam, Amsterdam, the Netherlands
- Cognitive Psychology, University of Leiden, Leiden, the Netherlands
| | - Esther Pelzer
- Translational Neurocircuitry, Max Planck Institute for Metabolism Research, Cologne, Germany
- Department of Neurology, University Clinics, Cologne, Germany
| | - Marc Tittgemeyer
- Translational Neurocircuitry, Max Planck Institute for Metabolism Research, Cologne, Germany
- Department of Neurology, University Clinics, Cologne, Germany
| | - Yasin Temel
- Department of Neurosurgery, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Birte. U. Forstmann
- Integrative Model-based Cognitive Neuroscience research unit, University of Amsterdam, Amsterdam, the Netherlands
| | - Max. C. Keuken
- Integrative Model-based Cognitive Neuroscience research unit, University of Amsterdam, Amsterdam, the Netherlands
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50
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Abstract
Live imaging studies in mice show that adult-born oligodendrocytes and myelin are remarkably stable. Neural activity enhances oligodendrocyte integration, arguing that internode addition rather than alteration represents the mechanism for any experience-dependent cortical myelination changes that might underpin learning.
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Affiliation(s)
- Matthew Swire
- MRC Centre for Regenerative Medicine, University of Edinburgh, Little France Drive, Edinburgh EH16 4UU, UK.
| | - Charles Ffrench-Constant
- MRC Centre for Regenerative Medicine, University of Edinburgh, Little France Drive, Edinburgh EH16 4UU, UK.
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