101
|
de Faria O, Gonsalvez DG, Nicholson M, Xiao J. Activity-dependent central nervous system myelination throughout life. J Neurochem 2018; 148:447-461. [PMID: 30225984 PMCID: PMC6587454 DOI: 10.1111/jnc.14592] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 09/07/2018] [Indexed: 01/03/2023]
Abstract
Myelin, the multilayered membrane surrounding many axons in the nervous system, increases the speed by which electrical signals travel along axons and facilitates neuronal communication between distant regions of the nervous system. However, how neuronal signals influence the myelinating process in the CNS is still largely unclear. Recent studies have significantly advanced this understanding, identifying important roles for neuronal activity in controlling oligodendrocyte development and their capacity of producing myelin in both developing and mature CNS. Here, we review these recent advances, and discuss potential mechanisms underpinning activity-dependent myelination and how remyelination may be stimulated via manipulating axonal activity, raising new questions for future research.
Collapse
Affiliation(s)
- Omar de Faria
- Wellcome Trust MRC Stem Cell Institute & Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - David G Gonsalvez
- Department of Anatomy and Neuroscience, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Madeline Nicholson
- Department of Anatomy and Neuroscience, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Junhua Xiao
- Department of Anatomy and Neuroscience, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria, Australia
| |
Collapse
|
102
|
Cornillot M, Giacco V, Hamilton NB. The role of TRP channels in white matter function and ischaemia. Neurosci Lett 2018; 690:202-209. [PMID: 30366011 DOI: 10.1016/j.neulet.2018.10.042] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 10/09/2018] [Accepted: 10/18/2018] [Indexed: 01/15/2023]
Abstract
Transient receptor potential (TRP) proteins are a large family of tetrameric non-selective cation channels that are widely expressed in the grey and white matter of the CNS, and are increasingly considered as potential therapeutic targets in brain disorders. Here we briefly review the evidence for TRP channel expression in glial cells and their possible role in both glial cell physiology and stroke. Despite their contribution to important functions, our understanding of the roles of TRP channels in glia is still in its infancy. The evidence reviewed here indicates that further investigation is needed to determine whether TRP channel inhibition can decrease damage or increase repair in stroke and other diseases affecting the white matter.
Collapse
Affiliation(s)
- Marion Cornillot
- Wolfson Centre for Age Related Disease, King's College London, Guy's Campus, London, SE1 1UL, United Kingdom
| | - Vincenzo Giacco
- Wolfson Centre for Age Related Disease, King's College London, Guy's Campus, London, SE1 1UL, United Kingdom
| | - Nicola B Hamilton
- Wolfson Centre for Age Related Disease, King's College London, Guy's Campus, London, SE1 1UL, United Kingdom.
| |
Collapse
|
103
|
Almeida RG. The Rules of Attraction in Central Nervous System Myelination. Front Cell Neurosci 2018; 12:367. [PMID: 30374292 PMCID: PMC6196289 DOI: 10.3389/fncel.2018.00367] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 09/27/2018] [Indexed: 12/12/2022] Open
Abstract
The wrapping of myelin around axons is crucial for the development and function of the central nervous system (CNS) of vertebrates, greatly regulating the conduction of action potentials. Oligodendrocytes, the myelinating glia of the CNS, have an intrinsic tendency to wrap myelin around any permissive structure in vitro, but in vivo, myelin is targeted with remarkable specificity only to certain axons. Despite the importance of myelination, the mechanisms by which oligodendrocytes navigate a complex milieu that includes many types of cells and their cellular projections and select only certain axons for myelination remains incompletely understood. In this Mini-review, I highlight recent studies that shed light on the molecular and cellular rules governing CNS myelin targeting.
Collapse
Affiliation(s)
- Rafael Góis Almeida
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| |
Collapse
|
104
|
Length of myelin internodes of individual oligodendrocytes is controlled by microenvironment influenced by normal and input‐deprived axonal activities in sensory deprived mouse models. Glia 2018; 66:2514-2525. [DOI: 10.1002/glia.23502] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 06/09/2018] [Accepted: 07/02/2018] [Indexed: 12/20/2022]
|
105
|
Stassart RM, Möbius W, Nave KA, Edgar JM. The Axon-Myelin Unit in Development and Degenerative Disease. Front Neurosci 2018; 12:467. [PMID: 30050403 PMCID: PMC6050401 DOI: 10.3389/fnins.2018.00467] [Citation(s) in RCA: 131] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 06/19/2018] [Indexed: 12/15/2022] Open
Abstract
Axons are electrically excitable, cable-like neuronal processes that relay information between neurons within the nervous system and between neurons and peripheral target tissues. In the central and peripheral nervous systems, most axons over a critical diameter are enwrapped by myelin, which reduces internodal membrane capacitance and facilitates rapid conduction of electrical impulses. The spirally wrapped myelin sheath, which is an evolutionary specialisation of vertebrates, is produced by oligodendrocytes and Schwann cells; in most mammals myelination occurs during postnatal development and after axons have established connection with their targets. Myelin covers the vast majority of the axonal surface, influencing the axon's physical shape, the localisation of molecules on its membrane and the composition of the extracellular fluid (in the periaxonal space) that immerses it. Moreover, myelinating cells play a fundamental role in axonal support, at least in part by providing metabolic substrates to the underlying axon to fuel its energy requirements. The unique architecture of the myelinated axon, which is crucial to its function as a conduit over long distances, renders it particularly susceptible to injury and confers specific survival and maintenance requirements. In this review we will describe the normal morphology, ultrastructure and function of myelinated axons, and discuss how these change following disease, injury or experimental perturbation, with a particular focus on the role the myelinating cell plays in shaping and supporting the axon.
Collapse
Affiliation(s)
- Ruth M. Stassart
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
- Department of Neuropathology, University Medical Center Leipzig, Leipzig, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
| | - Julia M. Edgar
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| |
Collapse
|
106
|
Abu-Rub M, Miller RH. Emerging Cellular and Molecular Strategies for Enhancing Central Nervous System (CNS) Remyelination. Brain Sci 2018; 8:brainsci8060111. [PMID: 29914096 PMCID: PMC6024921 DOI: 10.3390/brainsci8060111] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 06/12/2018] [Accepted: 06/13/2018] [Indexed: 02/06/2023] Open
Abstract
Myelination is critical for the normal functioning of the central nervous system (CNS) in vertebrates. Conditions in which the development of myelin is perturbed result in severely compromised individuals often with shorter lifespans, while loss of myelin in the adult results in a variety of functional deficits. Although some form of spontaneous remyelination often takes place, the repair process as a whole often fails. Several lines of evidence suggest it is feasible to develop strategies that enhance the capacity of the CNS to undergo remyelination and potentially reverse functional deficits. Such strategies include cellular therapies using either neural or mesenchymal stem cells as well as molecular regulators of oligodendrocyte development and differentiation. Given the prevalence of demyelinating diseases and their effects on the quality of life for affected individuals it is imperative that effective therapies are developed. Here we discuss some of the new approaches to CNS myelin repair that hold promise for reducing the burden of diseases characterized by myelin loss.
Collapse
Affiliation(s)
- Mohammad Abu-Rub
- Department of Neurology, George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA.
| | - Robert H Miller
- Department of Anatomy and Regenerative Biology, George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA.
| |
Collapse
|
107
|
Li T, Wang L, Ma T, Wang S, Niu J, Li H, Xiao L. Dynamic Calcium Release From Endoplasmic Reticulum Mediated by Ryanodine Receptor 3 Is Crucial for Oligodendroglial Differentiation. Front Mol Neurosci 2018; 11:162. [PMID: 29867353 PMCID: PMC5968115 DOI: 10.3389/fnmol.2018.00162] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 04/30/2018] [Indexed: 12/15/2022] Open
Abstract
Increased intracellular Ca2+ in oligodendrocyte progenitor cells (OPCs) is important to initiate their differentiation, but the intracellular Ca2+ channel involved in this process remains unclear. As a Ca2+-induced Ca2+ release (CICR) channel that mediates endoplasmic reticulum (ER) Ca2+ release, the role of ryanodine receptors (RyRs) in oligodendroglial development is unexplored. In the present study, we observed that among the three mammalian isoforms, oligodendroglial lineage cells selectively expressed RyR3. Strong RyR3-positive signal was distributed all over the cytoplasm and processes in OPCs and/or immature OLs (imOLs), whereas it gradually decreased and was located mainly around the perinuclear region in mature oligodendrocytes (OLs). In addition, RyR3-mediated intracellular Ca2+ waves following caffeine stimulation were correlated with the expression pattern of RyR3, in which high flat Ca2+ fluctuations and oscillatory Ca2+ waves were more frequently recorded in OPCs and/or imOLs than in OLs. Through further functional exploration, we demonstrated that pretreatment with the RyR antagonist ryanodine could neutralize the increase in intracellular Ca2+ induced by OPC differentiation and reduce the number of mature OLs. Moreover, gene-level knockdown of RyR3 by lentivirus in OPCs resulted in inhibition of OPC differentiation. Taken together, our results provide new insight into the crucial role of RyR3-mediated ER Ca2+ release in the regulation of OPC differentiation and/or myelination.
Collapse
Affiliation(s)
- Tao Li
- Chongqing Key Laboratory of Neurobiology, Department of Histology and Embryology, Third Military Medical University, Chongqing, China
| | - Lingyun Wang
- Chongqing Key Laboratory of Neurobiology, Department of Histology and Embryology, Third Military Medical University, Chongqing, China
| | - Teng Ma
- Chongqing Key Laboratory of Neurobiology, Department of Histology and Embryology, Third Military Medical University, Chongqing, China
| | - Shouyu Wang
- Chongqing Key Laboratory of Neurobiology, Department of Histology and Embryology, Third Military Medical University, Chongqing, China
| | - Jianqin Niu
- Chongqing Key Laboratory of Neurobiology, Department of Histology and Embryology, Third Military Medical University, Chongqing, China
| | - Hongli Li
- Chongqing Key Laboratory of Neurobiology, Department of Histology and Embryology, Third Military Medical University, Chongqing, China
| | - Lan Xiao
- Chongqing Key Laboratory of Neurobiology, Department of Histology and Embryology, Third Military Medical University, Chongqing, China
| |
Collapse
|
108
|
Correale J, Ysrraelit MC, Benarroch EE. Metabolic coupling of axons and glial cells. Neurology 2018; 90:737-744. [DOI: 10.1212/wnl.0000000000005339] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
109
|
Regulation of Central Nervous System Myelination in Higher Brain Functions. Neural Plast 2018; 2018:6436453. [PMID: 29692804 PMCID: PMC5859868 DOI: 10.1155/2018/6436453] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 01/03/2018] [Indexed: 12/04/2022] Open
Abstract
The hippocampus and the prefrontal cortex are interconnected brain regions, playing central roles in higher brain functions, including learning and memory, planning complex cognitive behavior, and moderating social behavior. The axons in these regions continue to be myelinated into adulthood in humans, which coincides with maturation of personality and decision-making. Myelin consists of dense layers of lipid membranes wrapping around the axons to provide electrical insulation and trophic support and can profoundly affect neural circuit computation. Recent studies have revealed that long-lasting changes of myelination can be induced in these brain regions by experience, such as social isolation, stress, and alcohol abuse, as well as by neurological and psychiatric abnormalities. However, the mechanism and function of these changes remain poorly understood. Myelin regulation represents a new form of neural plasticity. Some progress has been made to provide new mechanistic insights into activity-independent and activity-dependent regulations of myelination in different experimental systems. More extensive investigations are needed in this important but underexplored research field, in order to shed light on how higher brain functions and myelination interplay in the hippocampus and prefrontal cortex.
Collapse
|
110
|
Auer F, Vagionitis S, Czopka T. Evidence for Myelin Sheath Remodeling in the CNS Revealed by In Vivo Imaging. Curr Biol 2018; 28:549-559.e3. [PMID: 29429620 DOI: 10.1016/j.cub.2018.01.017] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 01/04/2018] [Accepted: 01/08/2018] [Indexed: 11/28/2022]
Abstract
The length of myelin sheaths affects conduction speed along axons and information propagation. It has recently become clear that myelin may be adaptively modified to modulate circuit function, implying that length remodeling of myelin sheaths should occur. However, direct evidence for such events is lacking. We have investigated how myelination patterns are formed, maintained, and remodeled using long-term imaging and myelin ablation in zebrafish. We demonstrate that length differences between myelin sheaths are established by rapid and variable growth within 3 days after their formation, independently of their time of formation, and even along discontinuously myelinated axons. Afterward, sheaths continue extending at similar rates to compensate for overall animal growth. In consequence, once axon myelination patterns are established, they are maintained over long periods of time. We tested whether mature myelin sheaths can remodel by removing individual sheaths from single axons by targeted ablation. Remarkably, extensive changes in sheath length and number occurred, which frequently restored the original myelination pattern. Our results show that axons can control myelin growth and remodeling, and we provide evidence for a homeostatic control of axon myelination patterns by maintenance and remodeling of myelin sheath length, with implications for circuit development, function, and repair.
Collapse
Affiliation(s)
- Franziska Auer
- Institute of Neuronal Cell Biology, Technical University of Munich, Biedersteiner Strasse 29, 80802 Munich, Germany; Graduate School of Systemic Neurosciences (GSN), Ludwig-Maximilian University of Munich, Großhaderner Strasse 2, 82152 Planegg-Martinsried, Germany
| | - Stavros Vagionitis
- Institute of Neuronal Cell Biology, Technical University of Munich, Biedersteiner Strasse 29, 80802 Munich, Germany
| | - Tim Czopka
- Institute of Neuronal Cell Biology, Technical University of Munich, Biedersteiner Strasse 29, 80802 Munich, Germany; Munich Cluster of Systems Neurology (SyNergy), Feodor-Lynen Strasse 17, 81377 Munich, Germany; Graduate School of Systemic Neurosciences (GSN), Ludwig-Maximilian University of Munich, Großhaderner Strasse 2, 82152 Planegg-Martinsried, Germany.
| |
Collapse
|
111
|
Baraban M, Koudelka S, Lyons DA. Ca 2+ activity signatures of myelin sheath formation and growth in vivo. Nat Neurosci 2018; 21:19-23. [PMID: 29230058 PMCID: PMC5742537 DOI: 10.1038/s41593-017-0040-x] [Citation(s) in RCA: 123] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Accepted: 11/05/2017] [Indexed: 12/19/2022]
Abstract
During myelination, individual oligodendrocytes initially over-produce short myelin sheaths, which are either retracted or stabilized. By live-imaging oligodendrocyte Ca2+ activity in vivo, we find that high-amplitude, long-duration Ca2+ transients in sheaths prefigure retractions, mediated by calpain. Following stabilization, myelin sheaths grow along axons, and we find that higher-frequency Ca2+ transient activity in sheaths precedes faster elongation. Our data implicate local Ca2+ signaling in regulating distinct stages of myelination.
Collapse
Affiliation(s)
- Marion Baraban
- Centre for Neuroregeneration, Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.
| | - Sigrid Koudelka
- Centre for Neuroregeneration, Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - David A Lyons
- Centre for Neuroregeneration, Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.
| |
Collapse
|