1
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Marshall-Phelps KLH, Almeida RG. Axonal neurotransmitter release in the regulation of myelination. Biosci Rep 2024; 44:BSR20231616. [PMID: 39230890 PMCID: PMC11427734 DOI: 10.1042/bsr20231616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Revised: 08/30/2024] [Accepted: 09/04/2024] [Indexed: 09/05/2024] Open
Abstract
Myelination of axons is a key determinant of fast action potential propagation, axonal health and circuit function. Previously considered a static structure, it is now clear that myelin is dynamically regulated in response to neuronal activity in the central nervous system (CNS). However, how activity-dependent signals are conveyed to oligodendrocytes remains unclear. Here, we review the potential mechanisms by which neurons could communicate changing activity levels to myelin, with a focus on the accumulating body of evidence to support activity-dependent vesicular signalling directly onto myelin sheaths. We discuss recent in vivo findings of activity-dependent fusion of neurotransmitter vesicles from non-synaptic axonal sites, and how modulation of this vesicular fusion regulates the stability and growth of myelin sheaths. We also consider the potential mechanisms by which myelin could sense and respond to axon-derived signals to initiate remodelling, and the relevance of these adaptations for circuit function. We propose that axonal vesicular signalling represents an important and underappreciated mode of communication by which neurons can transmit activity-regulated signals to myelinating oligodendrocytes and, potentially, more broadly to other cell types in the CNS.
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Affiliation(s)
- Katy L H Marshall-Phelps
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, U.K
- MS Society Edinburgh Centre for MS Research, University of Edinburgh, Edinburgh, U.K
| | - Rafael G Almeida
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, U.K
- MS Society Edinburgh Centre for MS Research, University of Edinburgh, Edinburgh, U.K
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2
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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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3
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Mi X, Chen ABY, Duarte D, Carey E, Taylor CR, Braaker PN, Bright M, Almeida RG, Lim JX, Ruetten VMS, Zheng W, Wang M, Reitman ME, Wang Y, Poskanzer KE, Lyons DA, Nimmerjahn A, Ahrens MB, Yu G. Fast, Accurate, and Versatile Data Analysis Platform for the Quantification of Molecular Spatiotemporal Signals. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.02.592259. [PMID: 38766026 PMCID: PMC11100599 DOI: 10.1101/2024.05.02.592259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Optical recording of intricate molecular dynamics is becoming an indispensable technique for biological studies, accelerated by the development of new or improved biosensors and microscopy technology. This creates major computational challenges to extract and quantify biologically meaningful spatiotemporal patterns embedded within complex and rich data sources, many of which cannot be captured with existing methods. Here, we introduce Activity Quantification and Analysis (AQuA2), a fast, accurate, and versatile data analysis platform built upon advanced machine learning techniques. It decomposes complex live imaging-based datasets into elementary signaling events, allowing accurate and unbiased quantification of molecular activities and identification of consensus functional units. We demonstrate applications across a wide range of biosensors, cell types, organs, animal models, and imaging modalities. As exemplar findings, we show how AQuA2 identified drug-dependent interactions between neurons and astroglia, and distinct sensorimotor signal propagation patterns in the mouse spinal cord.
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Affiliation(s)
- Xuelong Mi
- Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Arlington, VA 22203, USA
- These authors contributed equally
| | - Alex Bo-Yuan Chen
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
- Graduate Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA
- These authors contributed equally
| | - Daniela Duarte
- Waitt Advanced Biophotonics Center, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Erin Carey
- Waitt Advanced Biophotonics Center, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Charlotte R. Taylor
- Department of Biochemistry & Biophysics, University of California, San Francisco, CA, USA
- Neuroscience Graduate Program, University of California, San Francisco, CA, USA
| | - Philipp N. Braaker
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh BioQuarter, Edinburgh EH16 4SB, UK
| | - Mark Bright
- Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Arlington, VA 22203, USA
| | - Rafael G. Almeida
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh BioQuarter, Edinburgh EH16 4SB, UK
| | - Jing-Xuan Lim
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Virginia M. S. Ruetten
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
- Gatsby Computational Neuroscience Unit, UCL, London W1T 4JG, USA
| | - Wei Zheng
- Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Arlington, VA 22203, USA
| | - Mengfan Wang
- Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Arlington, VA 22203, USA
| | - Michael E. Reitman
- Department of Biochemistry & Biophysics, University of California, San Francisco, CA, USA
- Neuroscience Graduate Program, University of California, San Francisco, CA, USA
| | - Yizhi Wang
- Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Arlington, VA 22203, USA
| | - Kira E. Poskanzer
- Department of Biochemistry & Biophysics, University of California, San Francisco, CA, USA
- Neuroscience Graduate Program, University of California, San Francisco, CA, USA
- Kavli Institute for Fundamental Neuroscience, San Francisco, CA, USA
| | - David A. Lyons
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh BioQuarter, Edinburgh EH16 4SB, UK
| | - Axel Nimmerjahn
- Waitt Advanced Biophotonics Center, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Misha B. Ahrens
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Guoqiang Yu
- Department of Automation, Tsinghua University, Beijing 100084, China
- IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing 100084, China
- Lead contact
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4
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Gronseth JR, Nelson HN, Johnson TL, Mallon TA, Martell MR, Pfaffenbach KA, Duxbury BB, Henke JT, Treichel AJ, Hines JH. Synaptic vesicle release regulates pre-myelinating oligodendrocyte-axon interactions in a neuron subtype-specific manner. Front Cell Neurosci 2024; 18:1386352. [PMID: 38841202 PMCID: PMC11150666 DOI: 10.3389/fncel.2024.1386352] [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: 02/15/2024] [Accepted: 05/02/2024] [Indexed: 06/07/2024] Open
Abstract
Oligodendrocyte-lineage cells are central nervous system (CNS) glia that perform multiple functions including the selective myelination of some but not all axons. During myelination, synaptic vesicle release from axons promotes sheath stabilization and growth on a subset of neuron subtypes. In comparison, it is unknown if pre-myelinating oligodendrocyte process extensions selectively interact with specific neural circuits or axon subtypes, and whether the formation and stabilization of these neuron-glia interactions involves synaptic vesicle release. In this study, we used fluorescent reporters in the larval zebrafish model to track pre-myelinating oligodendrocyte process extensions interacting with spinal axons utilizing in vivo imaging. Monitoring motile oligodendrocyte processes and their interactions with individually labeled axons revealed that synaptic vesicle release regulates the behavior of subsets of process extensions. Specifically, blocking synaptic vesicle release decreased the longevity of oligodendrocyte process extensions interacting with reticulospinal axons. Furthermore, blocking synaptic vesicle release increased the frequency that new interactions formed and retracted. In contrast, tracking the movements of all process extensions of singly-labeled oligodendrocytes revealed that synaptic vesicle release does not regulate overall process motility or exploratory behavior. Blocking synaptic vesicle release influenced the density of oligodendrocyte process extensions interacting with reticulospinal and serotonergic axons, but not commissural interneuron or dopaminergic axons. Taken together, these data indicate that alterations to synaptic vesicle release cause changes to oligodendrocyte-axon interactions that are neuron subtype specific.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Jacob H. Hines
- Biology Department, Winona State University, Winona, MN, United States
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5
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Looser ZJ, Faik Z, Ravotto L, Zanker HS, Jung RB, Werner HB, Ruhwedel T, Möbius W, Bergles DE, Barros LF, Nave KA, Weber B, Saab AS. Oligodendrocyte-axon metabolic coupling is mediated by extracellular K + and maintains axonal health. Nat Neurosci 2024; 27:433-448. [PMID: 38267524 PMCID: PMC10917689 DOI: 10.1038/s41593-023-01558-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 12/13/2023] [Indexed: 01/26/2024]
Abstract
The integrity of myelinated axons relies on homeostatic support from oligodendrocytes (OLs). To determine how OLs detect axonal spiking and how rapid axon-OL metabolic coupling is regulated in the white matter, we studied activity-dependent calcium (Ca2+) and metabolite fluxes in the mouse optic nerve. We show that fast axonal spiking triggers Ca2+ signaling and glycolysis in OLs. OLs detect axonal activity through increases in extracellular potassium (K+) concentrations and activation of Kir4.1 channels, thereby regulating metabolite supply to axons. Both pharmacological inhibition and OL-specific inactivation of Kir4.1 reduce the activity-induced axonal lactate surge. Mice lacking oligodendroglial Kir4.1 exhibit lower resting lactate levels and altered glucose metabolism in axons. These early deficits in axonal energy metabolism are associated with late-onset axonopathy. Our findings reveal that OLs detect fast axonal spiking through K+ signaling, making acute metabolic coupling possible and adjusting the axon-OL metabolic unit to promote axonal health.
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Affiliation(s)
- Zoe J Looser
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Zainab Faik
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Luca Ravotto
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Henri S Zanker
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Ramona B Jung
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Torben Ruhwedel
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Dwight E Bergles
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA
| | - L Felipe Barros
- Centro de Estudios Científicos (CECs), Valdivia, Chile
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Valdivia, Chile
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Aiman S Saab
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland.
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland.
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6
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Li J, Miramontes TG, Czopka T, Monk KR. Synaptic input and Ca 2+ activity in zebrafish oligodendrocyte precursor cells contribute to myelin sheath formation. Nat Neurosci 2024; 27:219-231. [PMID: 38216650 DOI: 10.1038/s41593-023-01553-8] [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: 03/25/2022] [Accepted: 12/13/2023] [Indexed: 01/14/2024]
Abstract
In the nervous system, only one type of neuron-glial synapse is known to exist: that between neurons and oligodendrocyte precursor cells (OPCs), yet their composition, assembly, downstream signaling and in vivo functions remain largely unclear. Here, we address these questions using in vivo microscopy in zebrafish spinal cord and identify postsynaptic molecules PSD-95 and gephyrin in OPCs. The puncta containing these molecules in OPCs increase during early development and decrease upon OPC differentiation. These puncta are highly dynamic and frequently assemble at 'hotspots'. Gephyrin hotspots and synapse-associated Ca2+ activity in OPCs predict where a subset of myelin sheaths forms in differentiated oligodendrocytes. Further analyses reveal that spontaneous synaptic release is integral to OPC Ca2+ activity, while evoked synaptic release contributes only in early development. Finally, disruption of the synaptic genes dlg4a/dlg4b, gphnb and nlgn3b impairs OPC differentiation and myelination. Together, we propose that neuron-OPC synapses are dynamically assembled and can predetermine myelination patterns through Ca2+ signaling.
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Affiliation(s)
- Jiaxing Li
- Vollum Institute, Oregon Health & Science University, Portland, OR, USA.
| | | | - Tim Czopka
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Kelly R Monk
- Vollum Institute, Oregon Health & Science University, Portland, OR, USA.
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7
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Iyer M, Kantarci H, Cooper MH, Ambiel N, Novak SW, Andrade LR, Lam M, Jones G, Münch AE, Yu X, Khakh BS, Manor U, Zuchero JB. Oligodendrocyte calcium signaling promotes actin-dependent myelin sheath extension. Nat Commun 2024; 15:265. [PMID: 38177161 PMCID: PMC10767123 DOI: 10.1038/s41467-023-44238-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 12/05/2023] [Indexed: 01/06/2024] Open
Abstract
Myelin is essential for rapid nerve signaling and is increasingly found to play important roles in learning and in diverse diseases of the CNS. Morphological parameters of myelin such as sheath length are thought to precisely tune conduction velocity, but the mechanisms controlling sheath morphology are poorly understood. Local calcium signaling has been observed in nascent myelin sheaths and can be modulated by neuronal activity. However, the role of calcium signaling in sheath formation remains incompletely understood. Here, we use genetic tools to attenuate oligodendrocyte calcium signaling during myelination in the developing mouse CNS. Surprisingly, genetic calcium attenuation does not grossly affect the number of myelinated axons or myelin thickness. Instead, calcium attenuation causes myelination defects resulting in shorter, dysmorphic sheaths. Mechanistically, calcium attenuation reduces actin filaments in oligodendrocytes, and an intact actin cytoskeleton is necessary and sufficient to achieve accurate myelin morphology. Together, our work reveals a cellular mechanism required for accurate CNS myelin formation and may provide mechanistic insight into how oligodendrocytes respond to neuronal activity to sculpt and refine myelin sheaths.
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Affiliation(s)
- Manasi Iyer
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Husniye Kantarci
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Madeline H Cooper
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Nicholas Ambiel
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Sammy Weiser Novak
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Leonardo R Andrade
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Mable Lam
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Graham Jones
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Alexandra E Münch
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Xinzhu Yu
- Department of Molecular and Integrative Physiology, Beckman Institute, University of Illinois at Urbana-, Champaign, IL, USA
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Baljit S Khakh
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Uri Manor
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, USA
- Department of Cell and Developmental Biology, University of California, San Diego, San Diego, CA, USA
| | - J Bradley Zuchero
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA.
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8
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Moura D, Parvathaneni A, Sahagun A, Noguchi H, Garcia J, Brennan E, Brock R, Tilton I, Halladay L, Pleasure S, Cocas L. Neuronal Activity Changes the Number of Neurons That Are Synaptically Connected to OPCs. eNeuro 2023; 10:ENEURO.0126-23.2023. [PMID: 37813563 PMCID: PMC10598642 DOI: 10.1523/eneuro.0126-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 08/11/2023] [Accepted: 08/18/2023] [Indexed: 10/17/2023] Open
Abstract
The timing and specificity of oligodendrocyte myelination during development, as well as remyelination after injury or immune attack, remain poorly understood. Recent work has shown that oligodendrocyte progenitors receive synapses from neurons, providing a potential mechanism for neuronal-glial communication. In this study, we investigated the importance of these neuroglial connections in myelination during development and during neuronal plasticity in the mouse hippocampus. We used chemogenetic tools and viral monosynaptic circuit tracing to analyze these connections and to examine oligodendrocyte progenitor cells (OPCs) proliferation, myelination, synapse formation, and neuronal-glial connectivity in vivo after increasing or decreasing neuronal activity levels. We found that increasing neuronal activity led to greater OPC activation and proliferation. Modulation of neuronal activity also altered the organization of neuronal-glial connections: while it did not impact the total number of RabV-labeled neuronal inputs, or the number of RabV-labeled inhibitory neuronal (IN) inputs, it did alter the number of RabV-labeled excitatory neuron to OPC connections. Overall, our findings support the idea that neuronal activity plays a crucial role in regulating OPC proliferation and activation as well as the types of neuronal inputs to OPCs, indicating that neuronal activity is important for OPC circuit composition and function.
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Affiliation(s)
- Daniela Moura
- Biology Department, Neuroscience Program, Santa Clara University, Santa Clara, CA 95053
- Neurology Department, University of California, San Francisco, San Francisco, CA 94110
| | - Alekhya Parvathaneni
- Biology Department, Neuroscience Program, Santa Clara University, Santa Clara, CA 95053
| | - Atehsa Sahagun
- Biology Department, Neuroscience Program, Santa Clara University, Santa Clara, CA 95053
| | - Hirofumi Noguchi
- Neurology Department, University of California, San Francisco, San Francisco, CA 94110
| | - Jesse Garcia
- Neurology Department, University of California, San Francisco, San Francisco, CA 94110
| | - Emma Brennan
- Biology Department, Neuroscience Program, Santa Clara University, Santa Clara, CA 95053
| | - Robert Brock
- Biology Department, Neuroscience Program, Santa Clara University, Santa Clara, CA 95053
| | - Iris Tilton
- Biology Department, Neuroscience Program, Santa Clara University, Santa Clara, CA 95053
| | - Lindsay Halladay
- Biology Department, Neuroscience Program, Santa Clara University, Santa Clara, CA 95053
| | - Samuel Pleasure
- Neurology Department, University of California, San Francisco, San Francisco, CA 94110
| | - Laura Cocas
- Biology Department, Neuroscience Program, Santa Clara University, Santa Clara, CA 95053
- Neurology Department, University of California, San Francisco, San Francisco, CA 94110
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9
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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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10
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Iyer M, Kantarci H, Ambiel N, Novak SW, Andrade LR, Lam M, Münch AE, Yu X, Khakh BS, Manor U, Zuchero JB. Oligodendrocyte calcium signaling sculpts myelin sheath morphology. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.11.536299. [PMID: 37090556 PMCID: PMC10120717 DOI: 10.1101/2023.04.11.536299] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Myelin is essential for rapid nerve signaling and is increasingly found to play important roles in learning and in diverse diseases of the CNS. Morphological parameters of myelin such as sheath length and thickness are regulated by neuronal activity and can precisely tune conduction velocity, but the mechanisms controlling sheath morphology are poorly understood. Local calcium signaling has been observed in nascent myelin sheaths and can be modulated by neuronal activity. However, the role of calcium signaling in sheath formation and remodeling is unknown. Here, we used genetic tools to attenuate oligodendrocyte calcium signaling during active myelination in the developing mouse CNS. Surprisingly, we found that genetic calcium attenuation did not grossly affect the number of myelinated axons or myelin thickness. Instead, calcium attenuation caused striking myelination defects resulting in shorter, dysmorphic sheaths. Mechanistically, calcium attenuation reduced actin filaments in oligodendrocytes, and an intact actin cytoskeleton was necessary and sufficient to achieve accurate myelin morphology. Together, our work reveals a novel cellular mechanism required for accurate CNS myelin formation and provides mechanistic insight into how oligodendrocytes may respond to neuronal activity to sculpt myelin sheaths throughout the nervous system.
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11
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Kole K, Voesenek BJB, Brinia ME, Petersen N, Kole MHP. Parvalbumin basket cell myelination accumulates axonal mitochondria to internodes. Nat Commun 2022; 13:7598. [PMID: 36494349 PMCID: PMC9734141 DOI: 10.1038/s41467-022-35350-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Accepted: 11/30/2022] [Indexed: 12/13/2022] Open
Abstract
Parvalbumin-expressing (PV+) basket cells are fast-spiking inhibitory interneurons that exert critical control over local circuit activity and oscillations. PV+ axons are often myelinated, but the electrical and metabolic roles of interneuron myelination remain poorly understood. Here, we developed viral constructs allowing cell type-specific investigation of mitochondria with genetically encoded fluorescent probes. Single-cell reconstructions revealed that mitochondria selectively cluster to myelinated segments of PV+ basket cells, confirmed by analyses of a high-resolution electron microscopy dataset. In contrast to the increased mitochondrial densities in excitatory axons cuprizone-induced demyelination abolished mitochondrial clustering in PV+ axons. Furthermore, with genetic deletion of myelin basic protein the mitochondrial clustering was still observed at internodes wrapped by noncompacted myelin, indicating that compaction is dispensable. Finally, two-photon imaging of action potential-evoked calcium (Ca2+) responses showed that interneuron myelination attenuates both the cytosolic and mitochondrial Ca2+ transients. These findings suggest that oligodendrocyte ensheathment of PV+ axons assembles mitochondria to branch selectively fine-tune metabolic demands.
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Affiliation(s)
- Koen Kole
- grid.418101.d0000 0001 2153 6865Axonal Signaling Group, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, the Netherlands
| | - Bas J. B. Voesenek
- grid.418101.d0000 0001 2153 6865Axonal Signaling Group, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, the Netherlands
| | - Maria E. Brinia
- grid.418101.d0000 0001 2153 6865Axonal Signaling Group, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, the Netherlands ,grid.5216.00000 0001 2155 0800Medical School, National Kapodistrian University of Athens, Athens, 11527 Greece
| | - Naomi Petersen
- grid.418101.d0000 0001 2153 6865Axonal Signaling Group, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, the Netherlands
| | - Maarten H. P. Kole
- grid.418101.d0000 0001 2153 6865Axonal Signaling Group, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, the Netherlands ,grid.5477.10000000120346234Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
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12
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Nicholson M, Wood RJ, Gonsalvez DG, Hannan AJ, Fletcher JL, Xiao J, Murray SS. Remodelling of myelinated axons and oligodendrocyte differentiation is stimulated by environmental enrichment in the young adult brain. Eur J Neurosci 2022; 56:6099-6114. [PMID: 36217300 PMCID: PMC10092722 DOI: 10.1111/ejn.15840] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 09/30/2022] [Accepted: 10/05/2022] [Indexed: 12/29/2022]
Abstract
Oligodendrocyte production and myelination continues lifelong in the central nervous system (CNS), and all stages of this process can be adaptively regulated by neuronal activity. While artificial exogenous stimulation of neuronal circuits greatly enhances oligodendrocyte progenitor cell (OPC) production and increases myelination during development, the extent to which physiological stimuli replicates this is unclear, particularly in the adult CNS when the rate of new myelin addition slows. Here, we used environmental enrichment (EE) to physiologically stimulate neuronal activity for 6 weeks in 9-week-old C57BL/six male and female mice and found no increase in compact myelin in the corpus callosum or somatosensory cortex. Instead, we observed a global increase in callosal axon diameter with thicker myelin sheaths, elongated paranodes and shortened nodes of Ranvier. These findings indicate that EE induced the dynamic structural remodelling of myelinated axons. Additionally, we observed a global increase in the differentiation of OPCs and pre-myelinating oligodendroglia in the corpus callosum and somatosensory cortex. Our findings of structural remodelling of myelinated axons in response to physiological neural stimuli during young adulthood provide important insights in understanding experience-dependent myelin plasticity throughout the lifespan and provide a platform to investigate axon-myelin interactions in a physiologically relevant context.
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Affiliation(s)
- Madeline Nicholson
- Department of Anatomy and Physiology, University of Melbourne, Parkville, Australia
| | - Rhiannon J Wood
- Department of Anatomy and Physiology, University of Melbourne, Parkville, Australia
| | - David G Gonsalvez
- Department of Anatomy and Physiology, University of Melbourne, Parkville, Australia.,Department of Anatomy and Developmental Biology, Monash University, Clayton, Australia
| | - Anthony J Hannan
- Department of Anatomy and Physiology, University of Melbourne, Parkville, Australia.,Florey Institute of Neuroscience and Mental Health, Parkville, Australia
| | - Jessica L Fletcher
- Department of Anatomy and Physiology, University of Melbourne, Parkville, Australia.,Menzies Institute of Medical Research, University of Tasmania, Hobart, Australia
| | - Junhua Xiao
- School of Health Sciences, Swinburne University of Technology, Hawthorn, Victoria, Australia.,School of Allied Health, La Trobe University, Bundoora, Victoria, Australia
| | - Simon S Murray
- Department of Anatomy and Physiology, University of Melbourne, Parkville, Australia.,Florey Institute of Neuroscience and Mental Health, Parkville, Australia
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13
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Lysko DE, Talbot WS. Unmyelinated sensory neurons use Neuregulin signals to promote myelination of interneurons in the CNS. Cell Rep 2022; 41:111669. [PMID: 36384112 PMCID: PMC9719401 DOI: 10.1016/j.celrep.2022.111669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 09/06/2022] [Accepted: 10/25/2022] [Indexed: 11/17/2022] Open
Abstract
The signaling mechanisms neurons use to modulate myelination of circuits in the central nervous system (CNS) are only partly understood. Through analysis of isoform-specific neuregulin1 (nrg1) mutants in zebrafish, we demonstrate that nrg1 type II is an important regulator of myelination of two classes of spinal cord interneurons. Surprisingly, nrg1 type II expression is prominent in unmyelinated Rohon-Beard sensory neurons, whereas myelination of neighboring interneurons is reduced in nrg1 type II mutants. Cell-type-specific loss-of-function studies indicate that nrg1 type II is required in Rohon-Beard neurons to signal to other neurons, not oligodendrocytes, to modulate spinal cord myelination. Together, our data support a model in which unmyelinated neurons express Nrg1 type II proteins to regulate myelination of neighboring neurons, a mode of action that may coordinate the functions of unmyelinated and myelinated neurons in the CNS.
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Affiliation(s)
- Daniel E Lysko
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA
| | - William S Talbot
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA.
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14
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Wong HTC, Drerup CM. Using fluorescent indicators for in vivo quantification of spontaneous or evoked motor neuron presynaptic activity in transgenic zebrafish. STAR Protoc 2022; 3:101766. [PMID: 36240058 PMCID: PMC9568885 DOI: 10.1016/j.xpro.2022.101766] [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: 07/01/2022] [Revised: 08/22/2022] [Accepted: 09/20/2022] [Indexed: 11/07/2022] Open
Abstract
In this protocol, we describe steps that utilize the optical clarity of the zebrafish larvae and the stereotyped motor neuron axon structure in the trunk to measure spontaneous or evoked motor neuron axon activity. This activity is detected with transgenic fluorescent indicators introduced into the larvae by zygotic injection. Fluorescent indicator intensity changes in the small neuromuscular junctions are quantified to measure the presynaptic calcium activity and consequent synaptic vesicle release. For complete details on the use and execution of this protocol, please refer to Mandal et al. (2020).
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Affiliation(s)
- Hiu-tung Candy Wong
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA,Corresponding author
| | - Catherine M. Drerup
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA,Corresponding author
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15
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Lam M, Takeo K, Almeida RG, Cooper MH, Wu K, Iyer M, Kantarci H, Zuchero JB. CNS myelination requires VAMP2/3-mediated membrane expansion in oligodendrocytes. Nat Commun 2022; 13:5583. [PMID: 36151203 PMCID: PMC9508103 DOI: 10.1038/s41467-022-33200-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 09/07/2022] [Indexed: 11/08/2022] Open
Abstract
Myelin is required for rapid nerve signaling and is emerging as a key driver of CNS plasticity and disease. How myelin is built and remodeled remains a fundamental question of neurobiology. Central to myelination is the ability of oligodendrocytes to add vast amounts of new cell membrane, expanding their surface areas by many thousand-fold. However, how oligodendrocytes add new membrane to build or remodel myelin is not fully understood. Here, we show that CNS myelin membrane addition requires exocytosis mediated by the vesicular SNARE proteins VAMP2/3. Genetic inactivation of VAMP2/3 in myelinating oligodendrocytes caused severe hypomyelination and premature death without overt loss of oligodendrocytes. Through live imaging, we discovered that VAMP2/3-mediated exocytosis drives membrane expansion within myelin sheaths to initiate wrapping and power sheath elongation. In conjunction with membrane expansion, mass spectrometry of oligodendrocyte surface proteins revealed that VAMP2/3 incorporates axon-myelin adhesion proteins that are collectively required to form nodes of Ranvier. Together, our results demonstrate that VAMP2/3-mediated membrane expansion in oligodendrocytes is indispensable for myelin formation, uncovering a cellular pathway that could sculpt myelination patterns in response to activity-dependent signals or be therapeutically targeted to promote regeneration in disease.
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Affiliation(s)
- Mable Lam
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Koji Takeo
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
- Pharmaceutical Research Laboratories, Toray Industries, Inc., Kamakura, Kanagawa, Japan
| | - Rafael G Almeida
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Madeline H Cooper
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Kathryn Wu
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Manasi Iyer
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Husniye Kantarci
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - J Bradley Zuchero
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA.
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16
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Pan Y, Monje M. Neuron-Glial Interactions in Health and Brain Cancer. Adv Biol (Weinh) 2022; 6:e2200122. [PMID: 35957525 PMCID: PMC9845196 DOI: 10.1002/adbi.202200122] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 06/21/2022] [Indexed: 01/28/2023]
Abstract
Brain tumors are devastating diseases of the central nervous system. Brain tumor pathogenesis depends on both tumor-intrinsic oncogenic programs and extrinsic microenvironmental factors, including neurons and glial cells. Glial cells (oligodendrocytes, astrocytes, and microglia) make up half of the cells in the brain, and interact with neurons to modulate neurodevelopment and plasticity. Many brain tumor cells exhibit transcriptomic profiles similar to macroglial cells (oligodendrocytes and astrocytes) and their progenitors, making them likely to subvert existing neuron-glial interactions to support tumor pathogenesis. For example, oligodendrocyte precursor cells, a putative glioma cell of origin, can form bona fide synapses with neurons. Such synapses are recently identified in gliomas and drive glioma pathophysiology, underscoring how brain tumor cells can take advantage of neuron-glial interactions to support cancer progression. In this review, it is briefly summarized how neurons and their activity normally interact with glial cells and glial progenitors, and it is discussed how brain tumor cells utilize neuron-glial interactions to support tumor initiation and progression. Unresolved questions on these topics and potential avenues to therapeutically target neuron-glia-cancer interactions in the brain are also pointed out.
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Affiliation(s)
- Yuan Pan
- Department of Symptom Research, University of Texas MD Anderson Cancer Center,co-corresponding: ;
| | - Michelle Monje
- Department of Neurology, Stanford University,Howard Hughes Medical Institute, Stanford University,co-corresponding: ;
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17
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Wiltbank AT, Steinson ER, Criswell SJ, Piller M, Kucenas S. Cd59 and inflammation regulate Schwann cell development. eLife 2022; 11:e76640. [PMID: 35748863 PMCID: PMC9232220 DOI: 10.7554/elife.76640] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 06/01/2022] [Indexed: 11/13/2022] Open
Abstract
Efficient neurotransmission is essential for organism survival and is enhanced by myelination. However, the genes that regulate myelin and myelinating glial cell development have not been fully characterized. Data from our lab and others demonstrates that cd59, which encodes for a small GPI-anchored glycoprotein, is highly expressed in developing zebrafish, rodent, and human oligodendrocytes (OLs) and Schwann cells (SCs), and that patients with CD59 dysfunction develop neurological dysfunction during early childhood. Yet, the function of Cd59 in the developing nervous system is currently undefined. In this study, we demonstrate that cd59 is expressed in a subset of developing SCs. Using cd59 mutant zebrafish, we show that developing SCs proliferate excessively and nerves may have reduced myelin volume, altered myelin ultrastructure, and perturbed node of Ranvier assembly. Finally, we demonstrate that complement activity is elevated in cd59 mutants and that inhibiting inflammation restores SC proliferation, myelin volume, and nodes of Ranvier to wildtype levels. Together, this work identifies Cd59 and developmental inflammation as key players in myelinating glial cell development, highlighting the collaboration between glia and the innate immune system to ensure normal neural development.
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Affiliation(s)
- Ashtyn T Wiltbank
- Neuroscience Graduate Program, University of VirginiaCharlottesvilleUnited States
- Program in Fundamental Neuroscience, University of VirginiaCharlottesvilleUnited States
| | - Emma R Steinson
- Department of Biology, University of VirginiaCharlottesvilleUnited States
| | - Stacey J Criswell
- Department of Cell Biology, University of VirginiaCharlottesvilleUnited States
| | - Melanie Piller
- Department of Biology, University of VirginiaCharlottesvilleUnited States
| | - Sarah Kucenas
- Neuroscience Graduate Program, University of VirginiaCharlottesvilleUnited States
- Program in Fundamental Neuroscience, University of VirginiaCharlottesvilleUnited States
- Department of Biology, University of VirginiaCharlottesvilleUnited States
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18
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Khan S. Endoplasmic Reticulum in Metaplasticity: From Information Processing to Synaptic Proteostasis. Mol Neurobiol 2022; 59:5630-5655. [PMID: 35739409 DOI: 10.1007/s12035-022-02916-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 06/05/2022] [Indexed: 11/29/2022]
Abstract
The ER (endoplasmic reticulum) is a Ca2+ reservoir and the unique protein-synthesizing machinery which is distributed throughout the neuron and composed of multiple different structural domains. One such domain is called EMC (endoplasmic reticulum membrane protein complex), pleiotropic nature in cellular functions. The ER/EMC position inside the neurons unmasks its contribution to synaptic plasticity via regulating various cellular processes from protein synthesis to Ca2+ signaling. Since presynaptic Ca2+ channels and postsynaptic ionotropic receptors are organized into the nanodomains, thus ER can be a crucial player in establishing TMNCs (transsynaptic molecular nanocolumns) to shape efficient neural communications. This review hypothesized that ER is not only involved in stress-mediated neurodegeneration but also axon regrowth, remyelination, neurotransmitter switching, information processing, and regulation of pre- and post-synaptic functions. Thus ER might not only be a protein-synthesizing and quality control machinery but also orchestrates plasticity of plasticity (metaplasticity) within the neuron to execute higher-order brain functions and neural repair.
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Affiliation(s)
- Shumsuzzaman Khan
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, USA.
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19
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Fessel J. Reversing Alzheimer's disease dementia with clemastine, fingolimod, or rolipram, plus anti-amyloid therapy. ALZHEIMER'S & DEMENTIA (NEW YORK, N. Y.) 2022; 8:e12242. [PMID: 35128031 PMCID: PMC8804619 DOI: 10.1002/trc2.12242] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 11/09/2021] [Accepted: 12/13/2021] [Indexed: 12/17/2022]
Abstract
A few anti-amyloid trials offer a slight possibility of preventing progression of cognitive loss, but none has reversed the process. A possible reason is that amyloid may be necessary but insufficient in the pathogenesis of AD, and other causal factors may need addressing in addition to amyloid. It is argued here that drugs addressing myelination and synaptogenesis are the optimum partners for anti-amyloid drugs, since there is much evidence that early in the process that leads to AD, both neural circuits and synaptic activity are dysfunctional. Evidence to support this argument is presented. Evidence is also presented that clemastine, fingolimod, and rolipram, benefit both myelination and synaptogenesis. It is suggested that a regimen that includes one of them plus an anti-amyloid drug, could reverse AD.
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Affiliation(s)
- Jeffrey Fessel
- Professor of Clinical Medicine, Emeritus, Department of MedicineUniversity of California, San FranciscoSan FranciscoCaliforniaUSA
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20
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Chen JF, Wang F, Huang NX, Xiao L, Mei F. Oligodendrocytes and Myelin: Active players in Neurodegenerative brains? Dev Neurobiol 2022; 82:160-174. [PMID: 35081276 DOI: 10.1002/dneu.22867] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 11/10/2022]
Abstract
Oligodendrocytes (OLs) are a major type of glial cells in the central nervous system that generate multiple myelin sheaths to wrap axons. Myelin ensures fast and efficient propagation of action potentials along axons and supports neurons with nourishment. The decay of OLs and myelin has been implicated in age-related neurodegenerative diseases and these changes are generally considered as an inevitable result of neuron loss and axon degeneration. Noticeably, OLs and myelin undergo dynamic changes in healthy adult brains, that is, newly formed OLs are continuously added throughout life from the differentiation of oligodendrocyte precursor cells (OPCs) and the pre-existing myelin sheaths may undergo degeneration or remodeling. Increasing evidence has shown that changes in OLs and myelin are present in the early stages of neurodegenerative diseases, and even prior to significant neuronal loss and functional deficits. More importantly, oligodendroglia-specific manipulation, by either deletion of the disease gene or enhancement of myelin renewal, can alleviate functional impairments in neurodegenerative animal models. These findings underscore the possibility that OLs and myelin are not passively but actively involved in neurodegenerative diseases and may play an important role in modulating neuronal function and survival. In this review, we summarize recent work characterizing OL and myelin changes in both healthy and neurodegenerative brains and discuss the potential of targeting oligodendroglial cells in treating neurodegenerative diseases. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Jing-Fei Chen
- Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Department of Histology and Embryology, Third Military Medical University, Chongqing, 400038, China
| | - Fei Wang
- Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Department of Histology and Embryology, Third Military Medical University, Chongqing, 400038, China
| | - Nan-Xing Huang
- Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Department of Histology and Embryology, Third Military Medical University, Chongqing, 400038, China
| | - Lan Xiao
- Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Department of Histology and Embryology, Third Military Medical University, Chongqing, 400038, China
| | - Feng Mei
- Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Department of Histology and Embryology, Third Military Medical University, Chongqing, 400038, China
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21
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Moura DMS, Brennan EJ, Brock R, Cocas LA. Neuron to Oligodendrocyte Precursor Cell Synapses: Protagonists in Oligodendrocyte Development and Myelination, and Targets for Therapeutics. Front Neurosci 2022; 15:779125. [PMID: 35115904 PMCID: PMC8804499 DOI: 10.3389/fnins.2021.779125] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 12/17/2021] [Indexed: 12/17/2022] Open
Abstract
The development of neuronal circuitry required for cognition, complex motor behaviors, and sensory integration requires myelination. The role of glial cells such as astrocytes and microglia in shaping synapses and circuits have been covered in other reviews in this journal and elsewhere. This review summarizes the role of another glial cell type, oligodendrocytes, in shaping synapse formation, neuronal circuit development, and myelination in both normal development and in demyelinating disease. Oligodendrocytes ensheath and insulate neuronal axons with myelin, and this facilitates fast conduction of electrical nerve impulses via saltatory conduction. Oligodendrocytes also proliferate during postnatal development, and defects in their maturation have been linked to abnormal myelination. Myelination also regulates the timing of activity in neural circuits and is important for maintaining the health of axons and providing nutritional support. Recent studies have shown that dysfunction in oligodendrocyte development and in myelination can contribute to defects in neuronal synapse formation and circuit development. We discuss glutamatergic and GABAergic receptors and voltage gated ion channel expression and function in oligodendrocyte development and myelination. We explain the role of excitatory and inhibitory neurotransmission on oligodendrocyte proliferation, migration, differentiation, and myelination. We then focus on how our understanding of the synaptic connectivity between neurons and OPCs can inform future therapeutics in demyelinating disease, and discuss gaps in the literature that would inform new therapies for remyelination.
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Affiliation(s)
- Daniela M. S. Moura
- Department of Biology, Santa Clara University, Santa Clara, CA, United States
| | - Emma J. Brennan
- Department of Biology, Santa Clara University, Santa Clara, CA, United States
| | - Robert Brock
- Department of Biology, Santa Clara University, Santa Clara, CA, United States
| | - Laura A. Cocas
- Department of Biology, Santa Clara University, Santa Clara, CA, United States
- Department of Neurology, University of California, San Francisco, San Francisco, CA, United States
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22
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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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23
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Motavaf M, Piao X. Oligodendrocyte Development and Implication in Perinatal White Matter Injury. Front Cell Neurosci 2021; 15:764486. [PMID: 34803612 PMCID: PMC8599582 DOI: 10.3389/fncel.2021.764486] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 10/11/2021] [Indexed: 12/12/2022] Open
Abstract
Perinatal white matter injury (WMI) is the most common brain injury in premature infants and can lead to life-long neurological deficits such as cerebral palsy. Preterm birth is typically accompanied by inflammation and hypoxic-ischemic events. Such perinatal insults negatively impact maturation of oligodendrocytes (OLs) and cause myelination failure. At present, no treatment options are clinically available to prevent or cure WMI. Given that arrested OL maturation plays a central role in the etiology of perinatal WMI, an increased interest has emerged regarding the functional restoration of these cells as potential therapeutic strategy. Cell transplantation and promoting endogenous oligodendrocyte function are two potential options to address this major unmet need. In this review, we highlight the underlying pathophysiology of WMI with a specific focus on OL biology and their implication for the development of new therapeutic targets.
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Affiliation(s)
- Mahsa Motavaf
- Functional Neurosurgery Research Center, Shohada Tajrish Comprehensive Neurosurgical Center of Excellence, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Xianhua Piao
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, United States.,Newborn Brain Research Institute, University of California, San Francisco, San Francisco, CA, United States.,Weill Institute for Neuroscience, University of California, San Francisco, San Francisco, CA, United States.,Division of Neonatology, Department of Pediatrics, University of California, San Francisco, San Francisco, CA, United States
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24
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Heflin JK, Sun W. Novel Toolboxes for the Investigation of Activity-Dependent Myelination in the Central Nervous System. Front Cell Neurosci 2021; 15:769809. [PMID: 34795563 PMCID: PMC8592894 DOI: 10.3389/fncel.2021.769809] [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: 09/02/2021] [Accepted: 10/06/2021] [Indexed: 11/13/2022] Open
Abstract
Myelination is essential for signal processing within neural networks. Emerging data suggest that neuronal activity positively instructs myelin development and myelin adaptation during adulthood. However, the underlying mechanisms controlling activity-dependent myelination have not been fully elucidated. Myelination is a multi-step process that involves the proliferation and differentiation of oligodendrocyte precursor cells followed by the initial contact and ensheathment of axons by mature oligodendrocytes. Conventional end-point studies rarely capture the dynamic interaction between neurons and oligodendrocyte lineage cells spanning such a long temporal window. Given that such interactions and downstream signaling cascades are likely to occur within fine cellular processes of oligodendrocytes and their precursor cells, overcoming spatial resolution limitations represents another technical hurdle in the field. In this mini-review, we discuss how advanced genetic, cutting-edge imaging, and electrophysiological approaches enable us to investigate neuron-oligodendrocyte lineage cell interaction and myelination with both temporal and spatial precision.
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Affiliation(s)
- Jack Kent Heflin
- Department of Neuroscience, Wexner Medical Center, The Ohio State University, Columbus, OH, United States
| | - Wenjing Sun
- Department of Neuroscience, Wexner Medical Center, The Ohio State University, Columbus, OH, United States
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25
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Promoting growth through fusion. Nat Rev Neurosci 2021; 22:519. [PMID: 34331039 DOI: 10.1038/s41583-021-00510-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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