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Luo S, Wu F, Fang Q, Hu Y, Zhang H, Yuan S, Yang C, Shi Y, Luo Y. Antidepressant effect of teriflunomide via oligodendrocyte protection in a mouse model. Heliyon 2024; 10:e29481. [PMID: 38655332 PMCID: PMC11036017 DOI: 10.1016/j.heliyon.2024.e29481] [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] [Academic Contribution Register] [Received: 12/21/2023] [Revised: 04/05/2024] [Accepted: 04/08/2024] [Indexed: 04/26/2024] Open
Abstract
Addressing the treatment of depression is crucial; nevertheless, the etiology and pathogenesis remain unelucidated. Therefore, this study investigated the effects of teriflunomide (TF) on corticosterone (CORT)-induced depression-like behaviors in mice. Notably, TF administration resulted in a substantial amelioration of anxiety and depression-like behaviors observed in CORT-treated mice. This was evidenced by behavioral assessments conducted via the sucrose preference test (SPT), open-field test (OFT), novelty-suppressed feeding test (NSFT), forced swimming test (FST), and tail suspension test (TST). The administration of CORT inflicts damage upon oligodendrocytes and neurons within the hippocampus. Our findings indicate that TF offers significant protective effects on oligodendrocytes, mitigating apoptosis both invivo and invitro. Additionally, TF was found to counteract the CORT-induced neuronal loss and synaptic damage, as demonstrated by an increase in Nissl-positive cells across hippocampal regions CA1, CA3, and the dentate gyrus (DG) alongside elevated levels of synapse-related proteins including PSD-95 and synaptophysin. Additionally, TF treatment facilitated a reduction in the levels of apoptosis-related proteins while simultaneously augmenting the levels of Bcl2. Our findings indicate that TF administration effectively mitigates CORT-induced depression-like behaviors and reverses damage to oligodendrocytes and neurons in the hippocampus, suggesting TF as a promising candidate for depression.
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Affiliation(s)
- Shuting Luo
- School of Medicine, Hunan Normal University, Changsha, 410081, China
| | - Feilong Wu
- School of Medicine, Hunan Normal University, Changsha, 410081, China
| | - Qian Fang
- School of Medicine, Hunan Normal University, Changsha, 410081, China
| | - Yue Hu
- School of Medicine, Hunan Normal University, Changsha, 410081, China
| | - Huihui Zhang
- School of Medicine, Hunan Normal University, Changsha, 410081, China
| | - Shishan Yuan
- School of Medicine, Hunan Normal University, Changsha, 410081, China
| | - Chang Yang
- School of Medicine, Hunan Normal University, Changsha, 410081, China
| | - Yan Shi
- School of Medicine, Hunan Normal University, Changsha, 410081, China
| | - Yixiao Luo
- School of Medicine, Hunan Normal University, Changsha, 410081, China
- Hunan Province People's Hospital, The First-Affiliated Hospital of Hunan Normal University, Changsha, China
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2
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Perrier S, Gauquelin L, Bernard G. Inherited white matter disorders: Hypomyelination (myelin disorders). HANDBOOK OF CLINICAL NEUROLOGY 2024; 204:197-223. [PMID: 39322379 DOI: 10.1016/b978-0-323-99209-1.00014-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Academic Contribution Register] [Indexed: 09/27/2024]
Abstract
Hypomyelinating leukodystrophies are a subset of genetic white matter diseases characterized by insufficient myelin deposition during development. MRI patterns are used to identify hypomyelinating disorders, and genetic testing is used to determine the causal genes implicated in individual disease forms. Clinical course can range from severe, with patients manifesting neurologic symptoms in infancy or early childhood, to mild, with onset in adolescence or adulthood. This chapter discusses the most common hypomyelinating leukodystrophies, including X-linked Pelizaeus-Merzbacher disease and other PLP1-related disorders, autosomal recessive Pelizaeus-Merzbacher-like disease, and POLR3-related leukodystrophy. PLP1-related disorders are caused by hemizygous pathogenic variants in the proteolipid protein 1 (PLP1) gene, and encompass classic Pelizaeus-Merzbacher disease, the severe connatal form, PLP1-null syndrome, spastic paraplegia type 2, and hypomyelination of early myelinating structures. Pelizaeus-Merzbacher-like disease presents a similar clinical picture to Pelizaeus-Merzbacher disease, however, it is caused by biallelic pathogenic variants in the GJC2 gene, which encodes for the gap junction protein Connexin-47. POLR3-related leukodystrophy, or 4H leukodystrophy (hypomyelination, hypodontia, and hypogonadotropic hypogonadism), is caused by biallelic pathogenic variants in genes encoding specific subunits of the transcription enzyme RNA polymerase III. In this chapter, the clinical features, disease pathophysiology and genetics, imaging patterns, as well as supportive and future therapies are discussed for each disorder.
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Affiliation(s)
- Stefanie Perrier
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada; Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC, Canada
| | - Laurence Gauquelin
- Division of Pediatric Neurology, Department of Pediatrics, CHUL et Centre Mère-Enfant Soleil du CHU de Québec-Université Laval, Québec, QC, Canada
| | - Geneviève Bernard
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada; Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC, Canada; Departments of Pediatrics and Human Genetics, McGill University, Montréal, QC, Canada.
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3
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Gharesouran J, Hosseinzadeh H, Naghiloo A, Ghafouri-Fard S, Hussen BM, Taheri M, Rezazadeh M, Samadian M. Complete Loss of Myelin protein zero (MPZ) in a patient with a late onset Charcot-Marie-Tooth (CMT). Metab Brain Dis 2023; 38:1963-1970. [PMID: 36952089 DOI: 10.1007/s11011-023-01201-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Academic Contribution Register] [Received: 03/09/2022] [Accepted: 03/10/2023] [Indexed: 03/24/2023]
Abstract
Charcot-Marie-Tooth (CMT) comprises a group of hereditary neuropathies with clinical, epidemiological, and molecular heterogeneity in which variants in more than 80 different genes have been reported. One of the important genes which cause 5% of all CMT cases is Myelin protein zero (P0, MPZ). Variants in this gene have been reported in association with different forms of CMT including classical CMT1, severe DSS (CMT3B), DI-CMT, CMT2I and CMT2J with autosomal dominant (AD) inheritance. To our knowledge, MPZ variants have not been described in autosomal recessive (AR) form of CMT in previous studies. Moreover, its complete deletion has not been reported in human. Here, we described clinical characteristics of a patient with CMT symptoms who demonstrated manifestations of the disease late in his life. We performed exome sequencing for identifying CMT subtype and its associated gene, and follow that co-segregation analysis has been done to characterize inheritance pattern of the disorder. Through using exome sequencing, we identified a novel 4074 bp homozygote deletion which encompasses all 6 exons of the MPZ gene in this patient. After identifying the alteration, variant confirmation and co-segregation analysis have been performed by using specific primers. Our result revealed that the patient's parents were heterozygous for the alteration and they did not show any symptoms of CMT. Although most MPZ variants have been described with early onset CMT with AD pattern of inheritance, the reported patient in our study had late onset form and his parents did not show any symptoms. Considering substantial role of MPZ protein in the biogenesis of peripheral nervous system (PNS) myelin, we proposed that there should be another protein in PNS that compensates for lack of MPZ protein. Taken together, our finding is the first report of MPZ association with AR form of CMT with late onset features. Moreover, our results propose the presence of another protein in PNS myelin biogenesis and its assembly. However, functional studies alongside with other molecular studies are needed to confirm our results and identify the proposed protein.
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Affiliation(s)
- Jalal Gharesouran
- Department of Medical Genetics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Hassan Hosseinzadeh
- Department of Medical Genetics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Ali Naghiloo
- Department of Orthopedic Surgery, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Soudeh Ghafouri-Fard
- Department of Medical Genetics, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Bashdar Mahmud Hussen
- Department of Pharmacognosy, College of Pharmacy, Hawler Medical University, Erbil, Iraq
| | - Mohammad Taheri
- Urology and Nephrology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
- Institute of Human Genetics, Jena University Hospital, Jena, Germany.
| | - Maryam Rezazadeh
- Department of Medical Genetics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
| | - Mohammad Samadian
- Skull Base Research Center, Loghman Hakim Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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4
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Martens AK, Erwig M, Patzig J, Fledrich R, Füchtbauer EM, Werner HB. Targeted inactivation of the Septin2 and Septin9 genes in myelinating Schwann cells of mice. Cytoskeleton (Hoboken) 2023; 80:290-302. [PMID: 36378242 DOI: 10.1002/cm.21736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 09/08/2022] [Revised: 11/03/2022] [Accepted: 11/11/2022] [Indexed: 11/16/2022]
Abstract
The formation of axon-enwrapping myelin sheaths by oligodendrocytes in the central nervous system involves the assembly of a scaffolding septin filament comprised of the subunits SEPTIN2, SEPTIN4, SEPTIN7 and SEPTIN8. Conversely, in the peripheral nervous system (PNS), myelin is synthesized by a different cell type termed Schwann cells, and it remained unknown if septins also assemble as a multimer in PNS myelin. According to prior proteome analysis, PNS myelin comprises the subunits SEPTIN2, SEPTIN7, SEPTIN8, SEPTIN9, and SEPTIN11, which localize to the paranodal and abaxonal myelin subcompartments. Here, we use the Cre/loxP-system to delete the Septin9-gene specifically in Schwann cells, causing a markedly reduced abundance of SEPTIN9 in sciatic nerves, implying that Schwann cells are the main cell type expressing SEPTIN9 in the nerve. However, Septin9-deficiency in Schwann cells did not affect the abundance or localization of other septin subunits. In contrast, when deleting the Septin2-gene in Schwann cells the abundance of all relevant septin subunits was markedly reduced, including SEPTIN9. Notably, we did not find evidence that deleting Septin2 or Septin9 in Schwann cells impairs myelin biogenesis, nerve conduction velocity or motor/sensory capabilities, at least at the assessed timepoints. Our data thus show that SEPTIN2 but not SEPTIN9 is required for the formation or stabilization of a septin multimer in PNS myelin in vivo; however, its functional relevance remains to be established.
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Affiliation(s)
- Ann-Kristin Martens
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Michelle Erwig
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Julia Patzig
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Robert Fledrich
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | | | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
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5
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Mani A, Salinas I. The knowns and many unknowns of CNS immunity in teleost fish. FISH & SHELLFISH IMMUNOLOGY 2022; 131:431-440. [PMID: 36241002 DOI: 10.1016/j.fsi.2022.10.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Academic Contribution Register] [Received: 09/17/2022] [Revised: 10/04/2022] [Accepted: 10/07/2022] [Indexed: 06/16/2023]
Abstract
Many disease agents infect the central nervous system (CNS) of teleost fish causing severe losses for the fish farming sector. Yet, neurotropic fish pathogens remain poorly documented and immune responses in the teleost CNS essentially unknown. Previously thought to be devoid of an immune system, the mammalian CNS is now recognized to be protected from infection by diverse immune cells that mostly reside in the meningeal lymphatic system. Here we review the current body of work pertaining immune responses in the teleost CNS to infection. We identify important knowledge gaps with regards to CNS immunity in fish and make recommendations for rigorous experimentation and reporting in manuscripts so that fish immunologists can advance this burgeoning field.
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Affiliation(s)
- Amir Mani
- Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Irene Salinas
- Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA.
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6
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Ramasamy R, Hardy CC, Crocker SJ, Smith PP. Cuprizone-mediated demyelination reversibly degrades voiding behavior in mice while sparing brainstem reflex. J Neurosci Res 2022; 100:1707-1720. [PMID: 35596557 DOI: 10.1002/jnr.25065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 02/02/2022] [Revised: 03/30/2022] [Accepted: 04/22/2022] [Indexed: 11/12/2022]
Abstract
Multiple sclerosis (MS) is a chronic, progressively debilitating demyelinating disease of the central nervous system (CNS). Nearly 80% of MS patients experience lower urinary tract dysfunction early in their diagnosis. This significantly affects the quality of life, and in latter stages of disease is a leading cause of hospitalization. Previously, animal models have shown that inflammatory demyelination in the CNS causes profound bladder dysfunction, but the confounding influence of systemic inflammation limits the potential interpretation of the contribution of CNS demyelination to bladder dysfunction. Since the micturition circuit has myelinated neuronal connections in the cortex, brainstem, and spinal cord, we examined alterations in bladder function in the cuprizone model characterized by demyelinating lesions in the cortex and corpus callosum that are independent of T-cell-mediated autoimmunity. Herein, we report that a 4-week dietary cuprizone treatment in C57Bl/6J mice induced alterations in voiding behavior with increased micturition frequency and reduced volume voided, similar to human MS bladder dysfunction. Subsequently, recovery from cuprizone treatment restored normal bladder function. Demyelination and remyelination were confirmed by Luxol Fast Blue staining of the corpus callosum. Additionally, we also determined that an 8-week cuprizone treatment, resulting in chronic demyelination lacking spontaneous remyelination potential, is associated with an exacerbated voiding phenotype. Interestingly, while cuprizone-induced CNS demyelination severely affected conscious (cortical) urinary behavior, the brainstem and spinal cord reflex remained unchanged, as confirmed by urethane-anesthetized cystometry. This is the first study to show that cortical demyelination independent of inflammation can negatively impact urinary function.
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Affiliation(s)
- Ramalakshmi Ramasamy
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, Connecticut, USA.,UConn Center on Aging, University of Connecticut School of Medicine, Farmington, Connecticut, USA
| | - Cara C Hardy
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, Connecticut, USA.,UConn Center on Aging, University of Connecticut School of Medicine, Farmington, Connecticut, USA
| | - Stephen J Crocker
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, Connecticut, USA.,UConn Center on Aging, University of Connecticut School of Medicine, Farmington, Connecticut, USA
| | - Phillip P Smith
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, Connecticut, USA.,UConn Center on Aging, University of Connecticut School of Medicine, Farmington, Connecticut, USA.,Department of Surgery, University of Connecticut School of Medicine, Farmington, Connecticut, USA
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7
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A near-infrared AIE fluorescent probe for myelin imaging: From sciatic nerve to the optically cleared brain tissue in 3D. Proc Natl Acad Sci U S A 2021; 118:2106143118. [PMID: 34740969 PMCID: PMC8609329 DOI: 10.1073/pnas.2106143118] [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] [Academic Contribution Register] [Accepted: 09/23/2021] [Indexed: 12/25/2022] Open
Abstract
The high spatial resolution of three-dimensional (3D) fluorescence imaging of myelinated fibers will greatly facilitate the understanding of 3D neural networks and the pathophysiology of demyelinating diseases. However, existing myelin probes are far from satisfactory because of their low–signal-to-background ratio and poor tissue permeability. We herein developed a near-infrared aggregation-induced emission-active probe, PM-ML, for high-performance myelin imaging. PM-ML could specifically image myelinated fibers in teased sciatic nerves and mouse brain tissues with high contrast, good photostability, and deep penetration depth. PM-ML staining is compatible with several tissue-clearing methods. Its application in assessing myelination for neuropathological studies was also demonstrated using a multiple sclerosis mouse model. Myelin, the structure that surrounds and insulates neuronal axons, is an important component of the central nervous system. The visualization of the myelinated fibers in brain tissues can largely facilitate the diagnosis of myelin-related diseases and understand how the brain functions. However, the most widely used fluorescent probes for myelin visualization, such as Vybrant DiD and FluoroMyelin, have strong background staining, low-staining contrast, and low brightness. These drawbacks may originate from their self-quenching properties and greatly limit their applications in three-dimensional (3D) imaging and myelin tracing. Chemical probes for the fluorescence imaging of myelin in 3D, especially in optically cleared tissue, are highly desirable but rarely reported. We herein developed a near-infrared aggregation-induced emission (AIE)-active probe, PM-ML, for high-performance myelin imaging. PM-ML is plasma membrane targeting with good photostability. It could specifically label myelinated fibers in teased sciatic nerves and mouse brain tissues with a high–signal-to-background ratio. PM-ML could be used for 3D visualization of myelin sheaths, myelinated fibers, and fascicles with high-penetration depth. The staining is compatible with different brain tissue–clearing methods, such as ClearT and ClearT2. The utility of PM-ML staining in demyelinating disease studies was demonstrated using the mouse model of multiple sclerosis. Together, this work provides an important tool for high-quality myelin visualization across scales, which may greatly contribute to the study of myelin-related diseases.
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8
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Siems SB, Jahn O, Hoodless LJ, Jung RB, Hesse D, Möbius W, Czopka T, Werner HB. Proteome Profile of Myelin in the Zebrafish Brain. Front Cell Dev Biol 2021; 9:640169. [PMID: 33898427 PMCID: PMC8060510 DOI: 10.3389/fcell.2021.640169] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 12/10/2020] [Accepted: 03/05/2021] [Indexed: 12/14/2022] Open
Abstract
The velocity of nerve conduction along vertebrate axons depends on their ensheathment with myelin. Myelin membranes comprise specialized proteins well characterized in mice. Much less is known about the protein composition of myelin in non-mammalian species. Here, we assess the proteome of myelin biochemically purified from the brains of adult zebrafish (Danio rerio), considering its increasing popularity as model organism for myelin biology. Combining gel-based and gel-free proteomic approaches, we identified > 1,000 proteins in purified zebrafish myelin, including all known constituents. By mass spectrometric quantification, the predominant Ig-CAM myelin protein zero (MPZ/P0), myelin basic protein (MBP), and the short-chain dehydrogenase 36K constitute 12%, 8%, and 6% of the total myelin protein, respectively. Comparison with previously established mRNA-abundance profiles shows that expression of many myelin-related transcripts coincides with the maturation of zebrafish oligodendrocytes. Zebrafish myelin comprises several proteins that are not present in mice, including 36K, CLDNK, and ZWI. However, a surprisingly large number of ortholog proteins is present in myelin of both species, indicating partial evolutionary preservation of its constituents. Yet, the relative abundance of CNS myelin proteins can differ markedly as exemplified by the complement inhibitor CD59 that constitutes 5% of the total zebrafish myelin protein but is a low-abundant myelin component in mice. Using novel transgenic reporter constructs and cryo-immuno electron microscopy, we confirm the incorporation of CD59 into myelin sheaths. These data provide the first proteome resource of zebrafish CNS myelin and demonstrate both similarities and heterogeneity of myelin composition between teleost fish and rodents.
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Affiliation(s)
- Sophie B Siems
- Department of Neurogenetics, Max Planck Institute for Experimental Medicine, Göttingen, Germany
| | - Olaf Jahn
- Proteomics Group, Max Planck Institute for Experimental Medicine, Göttingen, Germany
| | - Laura J Hoodless
- Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| | - Ramona B Jung
- Department of Neurogenetics, Max Planck Institute for Experimental Medicine, Göttingen, Germany
| | - Dörte Hesse
- Proteomics Group, Max Planck Institute for Experimental Medicine, Göttingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute for Experimental Medicine, Göttingen, Germany.,Electron Microscopy Core Unit, Max Planck Institute for Experimental Medicine, Göttingen, Germany
| | - Tim Czopka
- Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute for Experimental Medicine, Göttingen, Germany
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9
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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: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution 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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10
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Abstract
Myelination of axons provides the structural basis for rapid saltatory impulse propagation along vertebrate fiber tracts, a well-established neurophysiological concept. However, myelinating oligodendrocytes and Schwann cells serve additional functions in neuronal energy metabolism that are remarkably similar to those of axon-ensheathing glial cells in unmyelinated invertebrates. Here we discuss myelin evolution and physiological glial functions, beginning with the role of ensheathing glia in preventing ephaptic coupling, axoglial metabolic support, and eliminating oxidative radicals. In both vertebrates and invertebrates, axoglial interactions are bidirectional, serving to regulate cell fate, nerve conduction, and behavioral performance. One key step in the evolution of compact myelin in the vertebrate lineage was the emergence of the open reading frame for myelin basic protein within another gene. Several other proteins were neofunctionalized as myelin constituents and help maintain a healthy nervous system. Myelination in vertebrates became a major prerequisite of inhabiting new ecological niches.
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Affiliation(s)
- Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, D-37075 Göttingen, Germany; ,
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, D-37075 Göttingen, Germany; ,
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11
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Bruggeman GF, Haitsma IK, Dirven CMF, Volovici V. Traumatic axonal injury (TAI): definitions, pathophysiology and imaging-a narrative review. Acta Neurochir (Wien) 2021; 163:31-44. [PMID: 33006648 PMCID: PMC7778615 DOI: 10.1007/s00701-020-04594-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 07/15/2020] [Accepted: 09/22/2020] [Indexed: 01/01/2023]
Abstract
Introduction Traumatic axonal injury (TAI) is a condition defined as multiple, scattered, small hemorrhagic, and/or non-hemorrhagic lesions, alongside brain swelling, in a more confined white matter distribution on imaging studies, together with impaired axoplasmic transport, axonal swelling, and disconnection after traumatic brain injury (TBI). Ever since its description in the 1980s and the grading system by Adams et al., our understanding of the processes behind this entity has increased. Methods We performed a scoping systematic, narrative review by interrogating Ovid MEDLINE, Embase, and Google Scholar on the pathophysiology, biomarkers, and diagnostic tools of TAI patients until July 2020. Results We underline the misuse of the Adams classification on MRI without proper validation studies, and highlight the hiatus in the scientific literature and areas needing more research. In the past, the theory behind the pathophysiology relied on the inertial force exerted on the brain matter after severe TBI inducing a primary axotomy. This theory has now been partially abandoned in favor of a more refined theory involving biochemical processes such as protein cleavage and DNA breakdown, ultimately leading to an inflammation cascade and cell apoptosis, a process now described as secondary axotomy. Conclusion The difference in TAI definitions makes the comparison of studies that report outcomes, treatments, and prognostic factors a daunting task. An even more difficult task is isolating the outcomes of isolated TAI from the outcomes of severe TBI in general. Targeted bench-to-bedside studies are required in order to uncover further pathways involved in the pathophysiology of TAI and, ideally, new treatments.
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Affiliation(s)
- Gavin F Bruggeman
- Department of Neurosurgery, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Iain K Haitsma
- Department of Neurosurgery, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Clemens M F Dirven
- Department of Neurosurgery, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Victor Volovici
- Department of Neurosurgery, Erasmus MC University Medical Center, Rotterdam, The Netherlands.
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12
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Chen CZ, Neumann B, Förster S, Franklin RJM. Schwann cell remyelination of the central nervous system: why does it happen and what are the benefits? Open Biol 2021; 11:200352. [PMID: 33497588 PMCID: PMC7881176 DOI: 10.1098/rsob.200352] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 10/29/2020] [Accepted: 01/07/2021] [Indexed: 12/18/2022] Open
Abstract
Myelin sheaths, by supporting axonal integrity and allowing rapid saltatory impulse conduction, are of fundamental importance for neuronal function. In response to demyelinating injuries in the central nervous system (CNS), oligodendrocyte progenitor cells (OPCs) migrate to the lesion area, proliferate and differentiate into new oligodendrocytes that make new myelin sheaths. This process is termed remyelination. Under specific conditions, demyelinated axons in the CNS can also be remyelinated by Schwann cells (SCs), the myelinating cell of the peripheral nervous system. OPCs can be a major source of these CNS-resident SCs-a surprising finding given the distinct embryonic origins, and physiological compartmentalization of the peripheral and central nervous system. Although the mechanisms and cues governing OPC-to-SC differentiation remain largely undiscovered, it might nevertheless be an attractive target for promoting endogenous remyelination. This article will (i) review current knowledge on the origins of SCs in the CNS, with a particular focus on OPC to SC differentiation, (ii) discuss the necessary criteria for SC myelination in the CNS and (iii) highlight the potential of using SCs for myelin regeneration in the CNS.
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Affiliation(s)
| | | | | | - Robin J. M. Franklin
- Wellcome-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0AH, UK
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13
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Roth LM, Zidane B, Festa L, Putatunda R, Romer M, Monnerie H, Jordan-Sciutto KL, Grinspan JB. Differential effects of integrase strand transfer inhibitors, elvitegravir and raltegravir, on oligodendrocyte maturation: A role for the integrated stress response. Glia 2020; 69:362-376. [PMID: 32894619 DOI: 10.1002/glia.23902] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 03/05/2020] [Revised: 08/12/2020] [Accepted: 08/13/2020] [Indexed: 12/15/2022]
Abstract
Regardless of adherence to combined antiretroviral therapy, white matter and myelin pathologies persist in patients with HIV-associated neurocognitive disorders, a spectrum of cognitive, motor, and behavioral impairments. We hypothesized that antiretroviral therapy alters the maturation of oligodendrocytes which synthesize myelin. We tested whether specific frontline integrase strand transfer inhibitors would alter oligodendrocyte differentiation and myelination. To model the effect of antiretrovirals on oligodendrocytes, we stimulated primary rat oligodendrocyte precursor cells to differentiate into mature oligodendrocytes in vitro in the presence of therapeutically relevant concentrations of elvitegravir or raltegravir and then assessed differentiation with lineage specific markers. To examine the effect of antiretrovirals on myelination, we treated mice with the demyelinating compound cuprizone, for 5 weeks. This was followed by 3 weeks of recovery in absence of cuprizone, during which time some mice received a daily intrajugular injection of elvitegravir. Brains were harvested, sectioned and processed by immunohistochemistry to examine oligodendrocyte maturation and myelination. Elvitegravir inhibited oligodendrocyte differentiation in vitro in a concentration-dependent manner, while raltegravir had no effect. Following cuprizone demyelination, administration of elvitegravir to adult mice reduced remyelination compared with control animals. Elvitegravir treatment activated the integrated stress response in oligodendrocytes in vitro, an effect which was completely blocked by pretreatment with the integrated stress response inhibitor Trans-ISRIB, preventing elvitegravir-mediated inhibition of oligodendrocyte maturation. These studies demonstrate that elvitegravir impairs oligodendrocyte maturation and remyelination and that the integrated stress response mediates this effect and may be a possible therapeutic target.
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Affiliation(s)
- Lindsay M Roth
- Department of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Bassam Zidane
- Department of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Lindsay Festa
- Department of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Raj Putatunda
- Department of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Micah Romer
- Department of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Hubert Monnerie
- Department of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Kelly L Jordan-Sciutto
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Judith B Grinspan
- Department of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
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14
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Raasakka A, Kursula P. How Does Protein Zero Assemble Compact Myelin? Cells 2020; 9:E1832. [PMID: 32759708 PMCID: PMC7465998 DOI: 10.3390/cells9081832] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 05/11/2020] [Revised: 07/21/2020] [Accepted: 07/30/2020] [Indexed: 02/06/2023] Open
Abstract
Myelin protein zero (P0), a type I transmembrane protein, is the most abundant protein in peripheral nervous system (PNS) myelin-the lipid-rich, periodic structure of membrane pairs that concentrically encloses long axonal segments. Schwann cells, the myelinating glia of the PNS, express P0 throughout their development until the formation of mature myelin. In the intramyelinic compartment, the immunoglobulin-like domain of P0 bridges apposing membranes via homophilic adhesion, forming, as revealed by electron microscopy, the electron-dense, double "intraperiod line" that is split by a narrow, electron-lucent space corresponding to the extracellular space between membrane pairs. The C-terminal tail of P0 adheres apposing membranes together in the narrow cytoplasmic compartment of compact myelin, much like myelin basic protein (MBP). In mouse models, the absence of P0, unlike that of MBP or P2, severely disturbs myelination. Therefore, P0 is the executive molecule of PNS myelin maturation. How and when P0 is trafficked and modified to enable myelin compaction, and how mutations that give rise to incurable peripheral neuropathies alter the function of P0, are currently open questions. The potential mechanisms of P0 function in myelination are discussed, providing a foundation for the understanding of mature myelin development and how it derails in peripheral neuropathies.
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Affiliation(s)
- Arne Raasakka
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, NO-5009 Bergen, Norway;
| | - Petri Kursula
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, NO-5009 Bergen, Norway;
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Aapistie 7A, FI-90220 Oulu, Finland
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15
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Steyer AM, Ruhwedel T, Nardis C, Werner HB, Nave KA, Möbius W. Pathology of myelinated axons in the PLP-deficient mouse model of spastic paraplegia type 2 revealed by volume imaging using focused ion beam-scanning electron microscopy. J Struct Biol 2020; 210:107492. [PMID: 32156581 PMCID: PMC7196930 DOI: 10.1016/j.jsb.2020.107492] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 09/06/2019] [Revised: 02/28/2020] [Accepted: 03/06/2020] [Indexed: 11/26/2022]
Abstract
Advances in electron microscopy including improved imaging techniques and state-of-the-art detectors facilitate imaging of larger tissue volumes with electron microscopic resolution. In combination with genetic tools for the generation of mouse mutants this allows assessing the three-dimensional (3D) characteristics of pathological features in disease models. Here we revisited the axonal pathology in the central nervous system of a mouse model of spastic paraplegia type 2, the Plp-/Y mouse. Although PLP is a bona fide myelin protein, the major hallmark of the disease in both SPG2 patients and mouse models are axonal swellings comprising accumulations of numerous organelles including mitochondria, gradually leading to irreversible axonal loss. To assess the number and morphology of axonal mitochondria and the overall myelin preservation we evaluated two sample preparation techniques, chemical fixation or high-pressure freezing and freeze substitution, with respect to the objective of 3D visualization. Both methods allowed visualizing distribution and morphological details of axonal mitochondria. In Plp-/Y mice the number of mitochondria is 2-fold increased along the entire axonal length. Mitochondria are also found in the excessive organelle accumulations within axonal swellings. In addition, organelle accumulations were detected within the myelin sheath and the inner tongue. We find that 3D electron microscopy is required for a comprehensive understanding of the size, content and frequency of axonal swellings, the hallmarks of axonal pathology.
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Affiliation(s)
- Anna M Steyer
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany; Electron Microscopy Core Unit, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany; Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Torben Ruhwedel
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany; Electron Microscopy Core Unit, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Christos Nardis
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany; Electron Microscopy Core Unit, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany; Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany; Electron Microscopy Core Unit, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany; Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany.
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16
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Raasakka A, Kursula P. Flexible Players within the Sheaths: The Intrinsically Disordered Proteins of Myelin in Health and Disease. Cells 2020; 9:cells9020470. [PMID: 32085570 PMCID: PMC7072810 DOI: 10.3390/cells9020470] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 01/30/2020] [Revised: 02/16/2020] [Accepted: 02/16/2020] [Indexed: 02/07/2023] Open
Abstract
Myelin ensheathes selected axonal segments within the nervous system, resulting primarily in nerve impulse acceleration, as well as mechanical and trophic support for neurons. In the central and peripheral nervous systems, various proteins that contribute to the formation and stability of myelin are present, which also harbor pathophysiological roles in myelin disease. Many myelin proteins have common attributes, including small size, hydrophobic segments, multifunctionality, longevity, and regions of intrinsic disorder. With recent advances in protein biophysical characterization and bioinformatics, it has become evident that intrinsically disordered proteins (IDPs) are abundant in myelin, and their flexible nature enables multifunctionality. Here, we review known myelin IDPs, their conservation, molecular characteristics and functions, and their disease relevance, along with open questions and speculations. We place emphasis on classifying the molecular details of IDPs in myelin, and we correlate these with their various functions, including susceptibility to post-translational modifications, function in protein–protein and protein–membrane interactions, as well as their role as extended entropic chains. We discuss how myelin pathology can relate to IDPs and which molecular factors are potentially involved.
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Affiliation(s)
- Arne Raasakka
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, NO-5009 Bergen, Norway;
| | - Petri Kursula
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, NO-5009 Bergen, Norway;
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Aapistie 7A, FI-90220 Oulu, Finland
- Correspondence:
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17
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Sabharwal V, Koushika SP. Crowd Control: Effects of Physical Crowding on Cargo Movement in Healthy and Diseased Neurons. Front Cell Neurosci 2019; 13:470. [PMID: 31708745 PMCID: PMC6823667 DOI: 10.3389/fncel.2019.00470] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 06/16/2019] [Accepted: 10/02/2019] [Indexed: 01/22/2023] Open
Abstract
High concentration of cytoskeletal filaments, organelles, and proteins along with the space constraints due to the axon's narrow geometry lead inevitably to intracellular physical crowding along the axon of a neuron. Local cargo movement is essential for maintaining steady cargo transport in the axon, and this may be impeded by physical crowding. Molecular motors that mediate active transport share movement mechanisms that allow them to bypass physical crowding present on microtubule tracks. Many neurodegenerative diseases, irrespective of how they are initiated, show increased physical crowding owing to the greater number of stalled organelles and structural changes associated with the cytoskeleton. Increased physical crowding may be a significant factor in slowing cargo transport to synapses, contributing to disease progression and culminating in the dying back of the neuronal process. This review explores the idea that physical crowding can impede cargo movement along the neuronal process. We examine the sources of physical crowding and strategies used by molecular motors that might enable cargo to circumvent physically crowded locations. Finally, we describe sub-cellular changes in neurodegenerative diseases that may alter physical crowding and discuss the implications of such changes on cargo movement.
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Affiliation(s)
| | - Sandhya P. Koushika
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
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18
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de Faria O, Gonsalvez DG, Nicholson M, Xiao J. Activity-dependent central nervous system myelination throughout life. J Neurochem 2019; 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] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution 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.
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Affiliation(s)
- Omar de Faria
- Wellcome Trust MRC Stem Cell Institute & Department of Veterinary MedicineUniversity of CambridgeCambridgeUK
| | - David G. Gonsalvez
- Department of Anatomy and NeuroscienceFaculty of MedicineDentistry and Health SciencesUniversity of MelbourneParkvilleVictoriaAustralia
| | - Madeline Nicholson
- Department of Anatomy and NeuroscienceFaculty of MedicineDentistry and Health SciencesUniversity of MelbourneParkvilleVictoriaAustralia
| | - Junhua Xiao
- Department of Anatomy and NeuroscienceFaculty of MedicineDentistry and Health SciencesUniversity of MelbourneParkvilleVictoriaAustralia
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19
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Ohno N, Ikenaka K. Axonal and neuronal degeneration in myelin diseases. Neurosci Res 2019; 139:48-57. [DOI: 10.1016/j.neures.2018.08.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 07/18/2018] [Revised: 08/22/2018] [Accepted: 08/29/2018] [Indexed: 12/14/2022]
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20
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Lüders KA, Nessler S, Kusch K, Patzig J, Jung RB, Möbius W, Nave KA, Werner HB. Maintenance of high proteolipid protein level in adult central nervous system myelin is required to preserve the integrity of myelin and axons. Glia 2019; 67:634-649. [PMID: 30637801 DOI: 10.1002/glia.23549] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 07/10/2018] [Revised: 09/24/2018] [Accepted: 10/01/2018] [Indexed: 12/20/2022]
Abstract
Proteolipid protein (PLP) is the most abundant integral membrane protein in central nervous system (CNS) myelin. Expression of the Plp-gene in oligodendrocytes is not essential for the biosynthesis of myelin membranes but required to prevent axonal pathology. This raises the question whether the exceptionally high level of PLP in myelin is required later in life, or whether high-level PLP expression becomes dispensable once myelin has been assembled. Both models require a better understanding of the turnover of PLP in myelin in vivo. Thus, we generated and characterized a novel line of tamoxifen-inducible Plp-mutant mice that allowed us to determine the rate of PLP turnover after developmental myelination has been completed, and to assess the possible impact of gradually decreasing amounts of PLP for myelin and axonal integrity. We found that 6 months after targeting the Plp-gene the abundance of PLP in CNS myelin was about halved, probably reflecting that myelin is slowly turned over in the adult brain. Importantly, this reduction by 50% was sufficient to cause the entire spectrum of neuropathological changes previously associated with the developmental lack of PLP, including myelin outfoldings, lamellae splittings, and axonal spheroids. In comparison to axonopathy and gliosis, the infiltration of cytotoxic T-cells was temporally delayed, suggesting a corresponding chronology also in the genetic disorders of PLP-deficiency. High-level abundance of PLP in myelin throughout adult life emerges as a requirement for the preservation of white matter integrity.
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Affiliation(s)
- Katja A Lüders
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Göttingen Graduate School for Neurosciences, Biophysics and Molecular Biosciences, Göttingen, Germany
| | - Stefan Nessler
- Institute of Neuropathology, University Medical Center Göttingen, Göttingen, Germany
| | - Kathrin Kusch
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Julia Patzig
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Ramona B Jung
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Göttingen, Germany
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
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21
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Sui Y, Nguyen HB, Thai TQ, Ikenaka K, Ohno N. Mitochondrial Dynamics in Physiology and Pathology of Myelinated Axons. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1190:145-163. [PMID: 31760643 DOI: 10.1007/978-981-32-9636-7_10] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Academic Contribution Register] [Indexed: 12/15/2022]
Abstract
Mitochondria play essential roles in neurons and abnormal functions of mitochondria have been implicated in neurological disorders including myelin diseases. Since mitochondrial functions are regulated and maintained by their dynamic behavior involving localization, transport, and fusion/fission, modulation of mitochondrial dynamics would be involved in physiology and pathology of myelinated axons. In fact, the integration of multimodal imaging in vivo and in vitro revealed that mitochondrial localization and transport are differentially regulated in nodal and internodal regions in response to the changes of metabolic demand in myelinated axons. In addition, the mitochondrial behavior in axons is modulated as adaptive responses to demyelination irrespective of the cause of myelin loss, and the behavioral modulation is partly through interactions with cytoskeletons and closely associated with the pathophysiology of demyelinating diseases. Furthermore, the behavior and functions of axonal mitochondria are modulated in congenital myelin disorders involving impaired interactions between axons and myelin-forming cells, and, together with the inflammatory environment, implicated in axonal degeneration and disease phenotypes. Further studies on the regulatory mechanisms of the mitochondrial dynamics in myelinated axons would provide deeper insights into axo-glial interactions mediated through myelin ensheathment, and effective manipulations of the dynamics may lead to novel therapeutic strategies protecting axonal and neuronal functions and survival in primary diseases of myelin.
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Affiliation(s)
- Yang Sui
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Aichi, Japan.,Departments of Anatomy and Structural Biology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo, Yamanashi, Japan
| | - Huy Bang Nguyen
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Aichi, Japan.,Departments of Anatomy and Structural Biology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo, Yamanashi, Japan
| | - Truc Quynh Thai
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Aichi, Japan.,Departments of Anatomy and Structural Biology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo, Yamanashi, Japan
| | - Kazuhiro Ikenaka
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
| | - Nobuhiko Ohno
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Aichi, Japan. .,Department of Anatomy, Division of Histology and Cell Biology, Jichi Medical University, School of Medicine, Shimotsuke, Japan.
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22
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Fletcher JL, Murray SS, Xiao J. Brain-Derived Neurotrophic Factor in Central Nervous System Myelination: A New Mechanism to Promote Myelin Plasticity and Repair. Int J Mol Sci 2018; 19:ijms19124131. [PMID: 30572673 PMCID: PMC6321406 DOI: 10.3390/ijms19124131] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 11/30/2018] [Revised: 12/18/2018] [Accepted: 12/18/2018] [Indexed: 12/27/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF) plays vitally important roles in neural development and plasticity in both health and disease. Recent studies using mutant mice to selectively manipulate BDNF signalling in desired cell types, in combination with animal models of demyelinating disease, have demonstrated that BDNF not only potentiates normal central nervous system myelination in development but enhances recovery after myelin injury. However, the precise mechanisms by which BDNF enhances myelination in development and repair are unclear. Here, we review some of the recent progress made in understanding the influence BDNF exerts upon the myelinating process during development and after injury, and discuss the cellular and molecular mechanisms underlying its effects. In doing so, we raise new questions for future research.
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Affiliation(s)
- Jessica L Fletcher
- Department of Anatomy and Neuroscience, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, 3010, VIC, Australia.
| | - Simon S Murray
- Department of Anatomy and Neuroscience, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, 3010, VIC, Australia.
| | - Junhua Xiao
- Department of Anatomy and Neuroscience, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, 3010, VIC, Australia.
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23
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Caprariello AV, Stys PK. Turned Inside Out: Will Myelin-Protective Therapies Become the Next-Generation Anti-Inflammatories? DNA Cell Biol 2018; 38:219-222. [PMID: 30461299 DOI: 10.1089/dna.2018.4496] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 01/13/2023] Open
Abstract
The earliest and most proximal triggers of inflammatory demyelination in multiple sclerosis (MS) remain an open question. In this DNACB review we address experimental and clinical evidence consistent with subtle perturbations of the axo-myelinic compartment of central nervous system white matter as initiation sites of secondary autoimmune demyelination in MS. Strengthened by experimental evidence that by inhibiting myelinopathy one can prevent inflammatory demyelination, myelin-protective therapies may represent a new class of anti-inflammatory medications for combating myelin autoimmunity.
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Affiliation(s)
- Andrew V Caprariello
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
| | - Peter K Stys
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
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24
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Torvund-Jensen J, Steengaard J, Askebjerg LB, Kjaer-Sorensen K, Laursen LS. The 3'UTRs of Myelin Basic Protein mRNAs Regulate Transport, Local Translation and Sensitivity to Neuronal Activity in Zebrafish. Front Mol Neurosci 2018; 11:185. [PMID: 29946237 PMCID: PMC6006989 DOI: 10.3389/fnmol.2018.00185] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 02/08/2018] [Accepted: 05/14/2018] [Indexed: 02/04/2023] Open
Abstract
Formation of functional myelin sheaths within the central nervous system depends on expression of myelin basic protein (MBP). Following process extension and wrapping around axonal segments, this highly basic protein is required for compaction of the multi-layered membrane sheath produced by oligodendrocytes. MBP is hypothesized to be targeted to the membrane sheath by mRNA transport and local translation, which ensures that its expression is temporally and spatially restricted. The mechanistic details of how this might be regulated are still largely unknown, in particular because a model system that allows this process to be studied in vivo is lacking. We here show that the expression of the zebrafish MBP orthologs, mbpa and mbpb, is developmentally regulated, and that expression of specific mbpa isoforms is restricted to the peripheral nervous system. By analysis of transgenic zebrafish, which express a fluorescent reporter protein specifically in myelinating oligodendrocytes, we demonstrate that both mbpa and mbpb include a 3’UTR sequence, by which mRNA transport and translation is regulated in vivo. Further functional analysis suggests that: (1) the 3’UTRs delay the onset of protein expression; and that (2) several regulatory elements contribute to targeting of the mbp mRNA to the myelin sheath. Finally, we show that a pharmacological compound known to enhance neuronal activity stimulates the translation of Mbp in zebrafish in a 3’UTR-dependent manner. A similar effect was obtained following stimulation with a TrkB receptor agonist, and cell-based assays further confirmed that the receptor ligand, BDNF, in combination with other signals reversed the inhibitory effect of the 3’UTR on translation.
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Affiliation(s)
- Julie Torvund-Jensen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Jes Steengaard
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | | | | | - Lisbeth S Laursen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
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25
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Xu B, Zhang Y, Zhan S, Wang X, Zhang H, Meng X, Ge W. Proteomic Profiling of Brain and Testis Reveals the Diverse Changes in Ribosomal Proteins in fmr1 Knockout Mice. Neuroscience 2017; 371:469-483. [PMID: 29292077 DOI: 10.1016/j.neuroscience.2017.12.023] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 06/07/2017] [Revised: 12/15/2017] [Accepted: 12/18/2017] [Indexed: 01/01/2023]
Abstract
Fragile X syndrome (FXS), the leading cause of inherited forms of mental retardation and autism, is caused by the transcriptional silencing of fmr1 encoding the fragile X mental retardation protein (FMRP). FMRP is an RNA-binding protein that is a widely expressed, but primarily in the brain and testis, and associated approximately 4% of transcripts. Macro-orchidism is a common symptom associated with FXS both in humans and mice. Thus, we analyze the pooled samples of cerebral cortex, hippocampus and testis from both the fmr1-KO and wild-type mice by a LC-MS/MS proteomic study. Among the identified proteins, most of those showing significant changes in expression were up- or downregulated in the absence of FMRP. Proteins (FMRP, RPS8, RPL23a and ATPIF1, RPL6, GAP43, MTCH2 and MPZ in brain, and FMRP, CAH3, AKR1B7 and C9 in testis) identified by MS/MS were also verified by Western blotting. The Gene Ontology and WikiPathways analysis revealed that the differentially expressed proteins were clustered in the polyribosome and RNA-binding protein categories in both cerebral cortex and hippocampus, but not in testis. Although this study was limited by the little number of samples, our results provide detailed insights into the ribosomal protein profiles of cerebral cortex, hippocampus and testis in the absence of FMRP. Our studies also provide a better understanding of protein profile changes and the underlying dysregulated pathways arising from fmr1 silencing in FXS.
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Affiliation(s)
- Benhong Xu
- Affiliated Hospital of Hebei University, No. 212, Yu Hua East Road, Nan Shi District, Baoding, Hebei 071000, China; State Key Laboratory of Medical Molecular Biology & Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, No. 5 Dongdansantiao, Dongcheng District, Beijing 100005, China; Key Laboratory of Modern Toxicology of Shenzhen, Institute of Toxicology, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China
| | - Yusheng Zhang
- State Key Laboratory of Medical Molecular Biology & Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, No. 5 Dongdansantiao, Dongcheng District, Beijing 100005, China
| | - Shaohua Zhan
- State Key Laboratory of Medical Molecular Biology & Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, No. 5 Dongdansantiao, Dongcheng District, Beijing 100005, China
| | - Xia Wang
- State Key Laboratory of Medical Molecular Biology & Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, No. 5 Dongdansantiao, Dongcheng District, Beijing 100005, China
| | - Haisong Zhang
- Affiliated Hospital of Hebei University, No. 212, Yu Hua East Road, Nan Shi District, Baoding, Hebei 071000, China
| | - Xianbin Meng
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Wei Ge
- Affiliated Hospital of Hebei University, No. 212, Yu Hua East Road, Nan Shi District, Baoding, Hebei 071000, China; State Key Laboratory of Medical Molecular Biology & Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, No. 5 Dongdansantiao, Dongcheng District, Beijing 100005, China.
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26
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Yin X, Kidd GJ, Ohno N, Perkins GA, Ellisman MH, Bastian C, Brunet S, Baltan S, Trapp BD. Proteolipid protein-deficient myelin promotes axonal mitochondrial dysfunction via altered metabolic coupling. J Cell Biol 2017; 215:531-542. [PMID: 27872255 PMCID: PMC5119941 DOI: 10.1083/jcb.201607099] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 07/25/2016] [Revised: 09/01/2016] [Accepted: 10/25/2016] [Indexed: 12/12/2022] Open
Abstract
The authors show that central nervous system myelin lacking proteolipid protein (PLP) induces mitochondrial dysfunction, including altered motility, degeneration, and ectopic smooth endoplasmic reticulum interactions, leading to axonal structural defects and degeneration. Mutated PLP occurs in hereditary spastic paraplegia, and these cellular effects provide potential insight into the pathology of the disease. Hereditary spastic paraplegia (HSP) is a neurological syndrome characterized by degeneration of central nervous system (CNS) axons. Mutated HSP proteins include myelin proteolipid protein (PLP) and axon-enriched proteins involved in mitochondrial function, smooth endoplasmic reticulum (SER) structure, and microtubule (MT) stability/function. We characterized axonal mitochondria, SER, and MTs in rodent optic nerves where PLP is replaced by the peripheral nerve myelin protein, P0 (P0-CNS mice). Mitochondrial pathology and degeneration were prominent in juxtaparanodal axoplasm at 1 mo of age. In wild-type (WT) optic nerve axons, 25% of mitochondria–SER associations occurred on extensions of the mitochondrial outer membrane. Mitochondria–SER associations were reduced by 86% in 1-mo-old P0-CNS juxtaparanodal axoplasm. 1-mo-old P0-CNS optic nerves were more sensitive to oxygen-glucose deprivation and contained less adenosine triphosphate (ATP) than WT nerves. MT pathology and paranodal axonal ovoids were prominent at 6 mo. These data support juxtaparanodal mitochondrial degeneration, reduced mitochondria–SER associations, and reduced ATP production as causes of axonal ovoid formation and axonal degeneration.
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Affiliation(s)
- Xinghua Yin
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Grahame J Kidd
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Nobuhiko Ohno
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Guy A Perkins
- National Center for Microscopy and Imaging Research, University of California, San Diego, La Jolla, CA 92093
| | - Mark H Ellisman
- National Center for Microscopy and Imaging Research, University of California, San Diego, La Jolla, CA 92093
| | - Chinthasagar Bastian
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Sylvain Brunet
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Selva Baltan
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Bruce D Trapp
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
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27
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Yoshimura T, Hayashi A, Handa-Narumi M, Yagi H, Ohno N, Koike T, Yamaguchi Y, Uchimura K, Kadomatsu K, Sedzik J, Kitamura K, Kato K, Trapp BD, Baba H, Ikenaka K. GlcNAc6ST-1 regulates sulfation of N-glycans and myelination in the peripheral nervous system. Sci Rep 2017; 7:42257. [PMID: 28186137 PMCID: PMC5301494 DOI: 10.1038/srep42257] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 09/30/2016] [Accepted: 01/05/2017] [Indexed: 01/09/2023] Open
Abstract
Highly specialized glial cells wrap axons with a multilayered myelin membrane in vertebrates. Myelin serves essential roles in the functioning of the nervous system. Axonal degeneration is the major cause of permanent neurological disability in primary myelin diseases. Many glycoproteins have been identified in myelin, and a lack of one myelin glycoprotein results in abnormal myelin structures in many cases. However, the roles of glycans on myelin glycoproteins remain poorly understood. Here, we report that sulfated N-glycans are involved in peripheral nervous system (PNS) myelination. PNS myelin glycoproteins contain highly abundant sulfated N-glycans. Major sulfated N-glycans were identified in both porcine and mouse PNS myelin, demonstrating that the 6-O-sulfation of N-acetylglucosamine (GlcNAc-6-O-sulfation) is highly conserved in PNS myelin between these species. P0 protein, the most abundant glycoprotein in PNS myelin and mutations in which at the glycosylation site cause Charcot-Marie-Tooth neuropathy, has abundant GlcNAc-6-O-sulfated N-glycans. Mice deficient in N-acetylglucosamine-6-O-sulfotransferase-1 (GlcNAc6ST-1) failed to synthesize sulfated N-glycans and exhibited abnormal myelination and axonal degeneration in the PNS. Taken together, this study demonstrates that GlcNAc6ST-1 modulates PNS myelination and myelinated axonal survival through the GlcNAc-6-O-sulfation of N-glycans on glycoproteins. These findings may provide novel insights into the pathogenesis of peripheral neuropathy.
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Affiliation(s)
- Takeshi Yoshimura
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
- Department of Physiological Sciences, School of Life Sciences, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan
| | - Akiko Hayashi
- Department of Molecular Neurobiology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Mai Handa-Narumi
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
- Department of Physiological Sciences, School of Life Sciences, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan
| | - Hirokazu Yagi
- Department of Structural Biology and Biomolecular Engineering, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Aichi 467-8603, Japan
| | - Nobuhiko Ohno
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
- Department of Physiological Sciences, School of Life Sciences, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan
| | - Takako Koike
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
| | - Yoshihide Yamaguchi
- Department of Molecular Neurobiology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Kenji Uchimura
- Department of Biochemistry, Graduate School of Medicine, Nagoya University, Nagoya, Aichi 466-8550, Japan
| | - Kenji Kadomatsu
- Department of Biochemistry, Graduate School of Medicine, Nagoya University, Nagoya, Aichi 466-8550, Japan
| | - Jan Sedzik
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
- Department of Chemical Engineering and Technology, Protein Crystallization Facility, Royal Institute of Technology, KTH, Stockholm 10044, Sweden
| | - Kunio Kitamura
- Faculty of Health and Medical Care, Saitama Medical University, Hidaka, Saitama 350-1241, Japan
| | - Koichi Kato
- Department of Structural Biology and Biomolecular Engineering, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Aichi 467-8603, Japan
- Institute for Molecular Science and Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
| | - Bruce D. Trapp
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Hiroko Baba
- Department of Molecular Neurobiology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Kazuhiro Ikenaka
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
- Department of Physiological Sciences, School of Life Sciences, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan
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28
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Maggipinto MJ, Ford J, Le KH, Tutolo JW, Furusho M, Wizeman JW, Bansal R, Barbarese E. Conditional knockout of TOG results in CNS hypomyelination. Glia 2017; 65:489-501. [PMID: 28063167 DOI: 10.1002/glia.23106] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 07/26/2016] [Revised: 10/29/2016] [Accepted: 11/30/2016] [Indexed: 12/12/2022]
Abstract
The tumor overexpressed gene (TOG) protein is present in RNA granules that transport myelin basic protein (MBP) mRNA in oligodendrocyte processes to the myelin compartment. Its role was investigated by conditionally knocking it out (KO) in myelinating glia in vivo. TOG KO mice have severe motor deficits that are already apparent at the time of weaning. This phenotype correlates with a paucity of myelin in several CNS regions, the most severe being in the spinal cord. In the TOG KO optic nerve <30% of axons are myelinated. The number of oligodendrocytes in the corpus callosum, cerebellum, and cervical spinal cord is normal. In the absence of TOG, the most patent biochemical change is a large reduction in MBP content, yet normal amounts of MBP transcripts are found in the brain of affected animals. MBP transcripts are largely confined to the cell body of the oligodendrocytes in the TOG KO in contrast to the situation in wild type mice where they are found in the processes of the oligodendrocytes and in the myelin compartment. These findings indicate that MBP gene expression involves a post-transcriptional TOG-dependent step. TOG may be necessary for MBP mRNA assembly into translation permissive granules, and/or for transport to preferred sites of translation. GLIA 2017;65:489-501.
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Affiliation(s)
- Michael J Maggipinto
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, Connecticut
| | - Joshay Ford
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, Connecticut
| | - Kristine H Le
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, Connecticut
| | - Jessica W Tutolo
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, Connecticut
| | - Miki Furusho
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, Connecticut
| | - John W Wizeman
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, Connecticut
| | - Rashmi Bansal
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, Connecticut
| | - Elisa Barbarese
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, Connecticut
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29
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Abstract
The mechanisms by which axonal degeneration occurs, even in the presence of apparently normal myelin sheaths, remain unknown. In this issue, Yin et al. (2016. J. Cell Biol. https://doi.org/10.1083/jcb.201607099) study mutant mice in which proteolipid protein is replaced by the peripheral myelin protein P0 and describe a number of early axonal abnormalities, which together suggest that aberrant mitochondrial energy metabolism precedes axonal degeneration.
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Affiliation(s)
- Bogdan Beirowski
- Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14203
| | - Elisabetta Babetto
- Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14203
| | - Lawrence Wrabetz
- Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14203
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30
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Abou-Abbass H, Bahmad H, Abou-El-Hassan H, Zhu R, Zhou S, Dong X, Hamade E, Mallah K, Zebian A, Ramadan N, Mondello S, Fares J, Comair Y, Atweh S, Darwish H, Zibara K, Mechref Y, Kobeissy F. Deciphering glycomics and neuroproteomic alterations in experimental traumatic brain injury: Comparative analysis of aspirin and clopidogrel treatment. Electrophoresis 2016; 37:1562-76. [PMID: 27249377 PMCID: PMC4963819 DOI: 10.1002/elps.201500583] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 12/24/2015] [Revised: 02/09/2016] [Accepted: 02/11/2016] [Indexed: 12/16/2022]
Abstract
As populations age, the number of patients sustaining traumatic brain injury (TBI) and concomitantly receiving preinjury antiplatelet therapy such as aspirin (ASA) and clopidogrel (CLOP) is rising. These drugs have been linked with unfavorable clinical outcomes following TBI, where the exact mechanism(s) involved are still unknown. In this novel work, we aimed to identify and compare the altered proteome profile imposed by ASA and CLOP when administered alone or in combination, prior to experimental TBI. Furthermore, we assessed differential glycosylation PTM patterns following experimental controlled cortical impact model of TBI, ASA, CLOP, and ASA + CLOP. Ipsilateral cortical brain tissues were harvested 48 h postinjury and were analyzed using an advanced neuroproteomics LC-MS/MS platform to assess proteomic and glycoproteins alterations. Of interest, differential proteins pertaining to each group (22 in TBI, 41 in TBI + ASA, 44 in TBI + CLOP, and 34 in TBI + ASA + CLOP) were revealed. Advanced bioinformatics/systems biology and clustering analyses were performed to evaluate biological networks and protein interaction maps illustrating molecular pathways involved in the experimental conditions. Results have indicated that proteins involved in neuroprotective cellular pathways were upregulated in the ASA and CLOP groups when given separately. However, ASA + CLOP administration revealed enrichment in biological pathways relevant to inflammation and proinjury mechanisms. Moreover, results showed differential upregulation of glycoproteins levels in the sialylated N-glycans PTMs that can be implicated in pathological changes. Omics data obtained have provided molecular insights of the underlying mechanisms that can be translated into clinical bedside settings.
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Affiliation(s)
- Hussein Abou-Abbass
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
- Faculty of Medicine, Beirut Arab University, Beirut, Lebanon
| | - Hisham Bahmad
- Faculty of Medicine, Beirut Arab University, Beirut, Lebanon
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | | | - Rui Zhu
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, USA
| | - Shiyue Zhou
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, USA
| | - Xue Dong
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, USA
| | - Eva Hamade
- ER045—Laboratory of Stem Cells, DSST, Lebanese University, Beirut, Lebanon
- Department of Biology, Faculty of Sciences-I, Lebanese University, Beirut, Lebanon
| | - Khalil Mallah
- ER045—Laboratory of Stem Cells, DSST, Lebanese University, Beirut, Lebanon
- Department of Biology, Faculty of Sciences-I, Lebanese University, Beirut, Lebanon
| | - Abir Zebian
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Naify Ramadan
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | | | - Jawad Fares
- Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Youssef Comair
- Department of Surgery, Division of Neurosurgery, Lebanese American University, Beirut, Lebanon
| | - Samir Atweh
- Department of Neurology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Hala Darwish
- Faculty of Medicine-School of Nursing, American University of Beirut, New York, NY, USA
| | - Kazem Zibara
- ER045—Laboratory of Stem Cells, DSST, Lebanese University, Beirut, Lebanon
- Department of Biology, Faculty of Sciences-I, Lebanese University, Beirut, Lebanon
| | - Yehia Mechref
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, USA
| | - Firas Kobeissy
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
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31
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Möbius W, Nave KA, Werner HB. Electron microscopy of myelin: Structure preservation by high-pressure freezing. Brain Res 2016; 1641:92-100. [PMID: 26920467 DOI: 10.1016/j.brainres.2016.02.027] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 02/09/2016] [Accepted: 02/16/2016] [Indexed: 10/24/2022]
Abstract
Electron microscopic visualization of nervous tissue morphology is crucial when aiming to understand the biogenesis and structure of myelin in healthy and pathological conditions. However, accurate interpretation of electron micrographs requires excellent tissue preservation. In this short review we discuss the recent utilization of tissue fixation by high-pressure freezing and freeze-substitution, which now supplements aldehyde fixation in the preparation of samples for electron microscopy of myelin. Cryofixation has proven well suited to yield both, improved contrast and excellent preservation of structural detail of the axon/myelin-unit in healthy and mutant mice and can also be applied to other model organisms, including aquatic species. This article is part of a Special Issue entitled SI: Myelin Evolution.
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Affiliation(s)
- Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany; Center for Nanoscale Microscopy and Molecular Physiology of the Brain, 37075 Göttingen, Germany.
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany.
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany.
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32
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Abstract
Myelin is probably one of the most fascinating and innovative biological acquisition: a glia plasma membrane tightly wrapped around an axon and insulating it. Chondrichthyans (cartilaginous fishes) form a large group of vertebrates, and they are among oldest extant jawed vertebrate lineage. It has been known from studies 150 years ago, that they are positioned at the root of the successful appearance of compact myelin and main adhesive proteins in vertebrates. More importantly, the ultrastructure of their compact myelin is indistinguishable from the one observed in tetrapods and the first true myelin basic protein (MBP) and myelin protein zero (MPZ) seem to have originated on cartilaginous fish or their ancestors, the placoderms. Thus, the study of their myelin formation would bring new insights in vertebrate׳s myelin evolution. Chondrichthyans central nervous system (CNS) myelin composition is also very similar to peripheral nervous system (PNS) myelin composition. And while they lack true proteolipid protein (PLP) like tetrapods, they express a DM-like protein in their myelin. This article is part of a Special Issue entitled SI: Myelin Evolution.
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Affiliation(s)
- Maria Elena de Bellard
- California State University Northridge, Biology Department, MC 8303, 18111 Nordhoff Street, Northridge, CA 91330, USA.
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33
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Wei W, Wang Y, Dong J, Wang Y, Min H, Song B, Shan Z, Teng W, Xi Q, Chen J. Hypothyroxinemia induced by maternal mild iodine deficiency impairs hippocampal myelinated growth in lactational rats. ENVIRONMENTAL TOXICOLOGY 2015; 30:1264-1274. [PMID: 24753110 DOI: 10.1002/tox.21997] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Academic Contribution Register] [Received: 10/31/2013] [Revised: 04/01/2014] [Accepted: 04/04/2014] [Indexed: 06/03/2023]
Abstract
Hypothyroxinemia induced by maternal mild iodine deficiency causes neurological deficits and impairments of brain function in offspring. Hypothyroxinemia is prevalent in developing and developed countries alike. However, the mechanism underlying these deficits remains less well known. Given that the myelin plays an important role in learning and memory function, we hypothesize that hippocampal myelinated growth may be impaired in rat offspring exposed to hypothyroxinemia induced by maternal mild iodine deficiency. To test this hypothesis, the female Wistar rats were used and four experimental groups were prepared: (1) control; (2) maternal mild iodine deficiency diet inducing hypothyroxinemia; (3) hypothyroidism induced by maternal severe iodine deficiency diet; (4) hypothyroidism induced by maternal methimazole water. The rats were fed the diet from 3 months before pregnancy to the end of lactation. Our results showed that the physiological changes occuring in the hippocampal myelin were altered in the mild iodine deficiency group as indicated by the results of immunofluorescence of myelin basic proteins on postnatal day 14 and postnatal day 21. Moreover, hypothyroxinemia reduced the expressions of oligodendrocyte lineage transcription factor 2 and myelin-related proteins in the treatments on postnatal day 14 and postnatal day 21. Our data suggested that hypothyroxinemia induced by maternal mild iodine deficiency may impair myelinated growth of the offspring.
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Affiliation(s)
- Wei Wei
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, People's Republic of China
- Department of Endocrinology and Metabolism and Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Hospital of China Medical University, Shenyang, People's Republic of China
| | - Yi Wang
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, People's Republic of China
- Department of Endocrinology and Metabolism and Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Hospital of China Medical University, Shenyang, People's Republic of China
| | - Jing Dong
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, People's Republic of China
- Department of Endocrinology and Metabolism and Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Hospital of China Medical University, Shenyang, People's Republic of China
| | - Yuan Wang
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, People's Republic of China
| | - Hui Min
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, People's Republic of China
| | - Binbin Song
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, People's Republic of China
| | - Zhongyan Shan
- Department of Endocrinology and Metabolism and Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Hospital of China Medical University, Shenyang, People's Republic of China
| | - Weiping Teng
- Department of Endocrinology and Metabolism and Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Hospital of China Medical University, Shenyang, People's Republic of China
| | - Qi Xi
- Department of Physiology, the University of Tennessee Health Science Center, Memphis, Tennessee, 38163, USA
| | - Jie Chen
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, People's Republic of China
- Department of Endocrinology and Metabolism and Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Hospital of China Medical University, Shenyang, People's Republic of China
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34
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Patzig J, Kusch K, Fledrich R, Eichel MA, Lüders KA, Möbius W, Sereda MW, Nave KA, Martini R, Werner HB. Proteolipid protein modulates preservation of peripheral axons and premature death when myelin protein zero is lacking. Glia 2015; 64:155-74. [PMID: 26393339 DOI: 10.1002/glia.22922] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 07/23/2015] [Accepted: 09/04/2015] [Indexed: 12/23/2022]
Abstract
Protein zero (P0) is the major structural component of peripheral myelin. Lack of this adhesion protein from Schwann cells causes a severe dysmyelinating neuropathy with secondary axonal degeneration in humans with the neuropathy Dejerine-Sottas syndrome (DSS) and in the corresponding mouse model (P0(null)-mice). In the mammalian CNS, the tetraspan-membrane protein PLP is the major structural myelin constituent and required for the long-term preservation of myelinated axons, which fails in hereditary spastic paraplegia (SPG type-2) and the relevant mouse model (Plp(null)-mice). The Plp-gene is also expressed in Schwann cells but PLP is of very low abundance in normal peripheral myelin; its function has thus remained enigmatic. Here we show that the abundance of PLP but not of other tetraspan myelin proteins is strongly increased in compact peripheral myelin of P0(null)-mice. To determine the functional relevance of PLP expression in the absence of P0, we generated P0(null)*Plp(null)-double-mutant mice. Compared with either single-mutant, P0(null)*Plp(null)-mice display impaired nerve conduction, reduced motor functions, and premature death. At the morphological level, axonal segments were frequently non-myelinated but in a one-to-one relationship with a hypertrophic Schwann cell. Importantly, axonal numbers were reduced in the vital phrenic nerve of P0(null)*Plp(null)-mice. In the absence of P0, thus, PLP also contributes to myelination by Schwann cells and to the preservation of peripheral axons. These data provide a link between the Schwann cell-dependent support of peripheral axons and the oligodendrocyte-dependent support of central axons.
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Affiliation(s)
- Julia Patzig
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Kathrin Kusch
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Robert Fledrich
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Maria A Eichel
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Katja A Lüders
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Göttingen, Germany
| | - Michael W Sereda
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Department of Clinical Neurophysiology, University Medical Center, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Rudolf Martini
- Department of Neurology, Developmental Neurobiology, University Hospital, Würzburg, Germany
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
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35
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Luoma AM, Kuo F, Cakici O, Crowther MN, Denninger AR, Avila RL, Brites P, Kirschner DA. Plasmalogen phospholipids protect internodal myelin from oxidative damage. Free Radic Biol Med 2015; 84:296-310. [PMID: 25801291 DOI: 10.1016/j.freeradbiomed.2015.03.012] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Academic Contribution Register] [Received: 07/18/2014] [Revised: 02/25/2015] [Accepted: 03/12/2015] [Indexed: 12/16/2022]
Abstract
Reactive oxygen species (ROS) are implicated in a range of degenerative conditions, including aging, neurodegenerative diseases, and neurological disorders. Myelin is a lipid-rich multilamellar sheath that facilitates rapid nerve conduction in vertebrates. Given the high energetic demands and low antioxidant capacity of the cells that elaborate the sheaths, myelin is considered intrinsically vulnerable to oxidative damage, raising the question whether additional mechanisms prevent structural damage. We characterized the structural and biochemical basis of ROS-mediated myelin damage in murine tissues from both central nervous system (CNS) and peripheral nervous system (PNS). To determine whether ROS can cause structural damage to the internodal myelin, whole sciatic and optic nerves were incubated ex vivo with a hydroxyl radical-generating system consisting of copper (Cu), hydrogen peroxide (HP), and ortho-phenanthroline (OP). Quantitative assessment of unfixed tissue by X-ray diffraction revealed irreversible compaction of myelin membrane stacking in both sciatic and optic nerves. Incubation in the presence of the hydroxyl radical scavenger sodium formate prevented this damage, implicating hydroxyl radical species. Myelin membranes are particularly enriched in plasmalogens, a class of ether-linked phospholipids proposed to have antioxidant properties. Myelin in sciatic nerve from plasmalogen-deficient (Pex7 knockout) mice was significantly more vulnerable to Cu/OP/HP-mediated ROS-induced compaction than myelin from WT mice. Our results directly support the role of plasmalogens as endogenous antioxidants providing a defense that protects ROS-vulnerable myelin.
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Affiliation(s)
- Adrienne M Luoma
- Biology Department, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA 02467-3811, USA
| | - Fonghsu Kuo
- Biology Department, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA 02467-3811, USA
| | - Ozgur Cakici
- Biology Department, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA 02467-3811, USA
| | - Michelle N Crowther
- Biology Department, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA 02467-3811, USA
| | - Andrew R Denninger
- Biology Department, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA 02467-3811, USA
| | - Robin L Avila
- Biology Department, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA 02467-3811, USA
| | - Pedro Brites
- Nerve Regeneration Group, Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Daniel A Kirschner
- Biology Department, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA 02467-3811, USA.
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Abstract
Myelination of axons in the nervous system of vertebrates enables fast, saltatory impulse propagation, one of the best-understood concepts in neurophysiology. However, it took a long while to recognize the mechanistic complexity both of myelination by oligodendrocytes and Schwann cells and of their cellular interactions. In this review, we highlight recent advances in our understanding of myelin biogenesis, its lifelong plasticity, and the reciprocal interactions of myelinating glia with the axons they ensheath. In the central nervous system, myelination is also stimulated by axonal activity and astrocytes, whereas myelin clearance involves microglia/macrophages. Once myelinated, the long-term integrity of axons depends on glial supply of metabolites and neurotrophic factors. The relevance of this axoglial symbiosis is illustrated in normal brain aging and human myelin diseases, which can be studied in corresponding mouse models. Thus, myelinating cells serve a key role in preserving the connectivity and functions of a healthy nervous system.
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Affiliation(s)
- Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, D-37075 Göttingen, Germany; ,
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37
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Heinecke KA, Luoma A, d'Azzo A, Kirschner DA, Seyfried TN. Myelin abnormalities in the optic and sciatic nerves in mice with GM1-gangliosidosis. ASN Neuro 2015; 7:7/1/1759091415568913. [PMID: 25694553 PMCID: PMC4342369 DOI: 10.1177/1759091415568913] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 01/28/2023] Open
Abstract
GM1-gangliosidosis is a glycosphingolipid lysosomal storage disease involving accumulation of GM1 and its asialo form (GA1) primarily in the brain. Thin-layer chromatography and X-ray diffraction were used to analyze the lipid content/composition and the myelin structure of the optic and sciatic nerves from 7- and 10-month old β-galactosidase (β-gal) +/? and β-gal −/− mice, a model of GM1gangliosidosis. Optic nerve weight was lower in the β-gal −/− mice than in unaffected β-gal +/? mice, but no difference was seen in sciatic nerve weight. The levels of GM1 and GA1 were significantly increased in both the optic nerve and sciatic nerve of the β-gal −/− mice. The content of myelin-enriched cerebrosides, sulfatides, and plasmalogen ethanolamines was significantly lower in optic nerve of β-gal −/− mice than in β-gal +/? mice; however, cholesteryl esters were enriched in the β-gal −/− mice. No major abnormalities in these lipids were detected in the sciatic nerve of the β-gal −/− mice. The abnormalities in GM1 and myelin lipids in optic nerve of β-gal −/− mice correlated with a reduction in the relative amount of myelin and periodicity in fresh nerve. By contrast, the relative amount of myelin and periodicity in the sciatic nerves from control and β-gal −/− mice were indistinguishable, suggesting minimal pathological involvement in sciatic nerve. Our results indicate that the greater neurochemical pathology observed in the optic nerve than in the sciatic nerve of β-gal −/− mice is likely due to the greater glycolipid storage in optic nerve.
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Affiliation(s)
| | - Adrienne Luoma
- Department of Biology, Boston College, Chestnut Hill, MA, USA Department of Biochemistry and Molecular Biology, Committee on Immunology, University of Chicago, IL, USA
| | - Alessandra d'Azzo
- Department of Genetics, St. Jude Children's Research Hospital, Memphis, TN, USA
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38
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DeLuca GC, Yates RL, Beale H, Morrow SA. Cognitive impairment in multiple sclerosis: clinical, radiologic and pathologic insights. Brain Pathol 2015; 25:79-98. [PMID: 25521179 PMCID: PMC8029470 DOI: 10.1111/bpa.12220] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 10/15/2014] [Accepted: 10/15/2014] [Indexed: 01/18/2023] Open
Abstract
Cognitive impairment is a common and debilitating feature of multiple sclerosis (MS) that has only recent gained considerable attention. Clinical neuropsychological studies have made apparent the multifaceted nature of cognitive troubles often encountered in MS and continue to broaden our understanding of its complexity. Radiographic studies have started to decipher the neuroanatomic substrate of MS-related cognitive impairment and have shed light onto its pathogenesis. Where radiographic studies have been limited by inadequate resolution or non-specificity, pathological studies have come to the fore. This review aims to provide an overview of the nature of cognitive impairment typically seen in MS and to explore the literature on imaging and pathological studies relevant to its evolution. In particular, the relative contributions of gray (i.e., cerebral cortex, hippocampus, thalamus and basal ganglia) and white matter to MS-related cognitive impairment will be discussed and the importance of interconnectivity between structures highlighted. The pressing need for longitudinal studies combining standardized neuropsychometric, paraclinical and radiographic outcomes obtained during life with post-mortem tissue analysis after death is presented.
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Affiliation(s)
- Gabriele C. DeLuca
- Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
| | - Richard L. Yates
- Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
| | - Harry Beale
- Oxford Medical SchoolUniversity of OxfordOxfordUK
| | - Sarah A. Morrow
- Department of Clinical Neurological SciencesThe University of Western OntarioLondonCanada
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Torii T, Miyamoto Y, Yamauchi J, Tanoue A. Pelizaeus-Merzbacher disease: cellular pathogenesis and pharmacologic therapy. Pediatr Int 2014; 56:659-66. [PMID: 25040584 DOI: 10.1111/ped.12450] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Academic Contribution Register] [Received: 02/13/2014] [Revised: 06/30/2014] [Accepted: 07/07/2014] [Indexed: 01/18/2023]
Abstract
Pelizaeus-Merzbacher disease (PMD) is a rare leukodystrophy that causes severe dysmyelination in the central nervous system in infancy and early childhood. Many previous studies showed that various proteolipid protein 1 (plp1) mutations, including duplications, point mutations, and deletions, lead to oligodendrocyte dysfunction in patients with PMD. PMD onset and clinical severity range widely, depending on the type of plp1 mutation. Patients with PMD exhibit a delayed mental and physical development phenotype, but specific pharmacological therapy and clinical treatment for PMD are not yet well established. This review describes PMD pathology and establishment of new clinical treatment for PMD. These findings support the development of a new therapy for PMD and these treatments may improve the quality of life in patients with PMD.
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Affiliation(s)
- Tomohiro Torii
- Department of Pharmacology, National Research Institute for Child Health and Development, Tokyo, Japan
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Yin X, Kiryu-Seo S, Kidd GJ, Feltri ML, Wrabetz L, Trapp BD. Proteolipid protein cannot replace P0 protein as the major structural protein of peripheral nervous system myelin. Glia 2014; 63:66-77. [PMID: 25066805 DOI: 10.1002/glia.22733] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 04/23/2014] [Accepted: 07/14/2014] [Indexed: 11/10/2022]
Abstract
The central nervous system (CNS) of terrestrial vertebrates underwent a prominent molecular change when proteolipid protein (PLP) replaced P0 protein as the most abundant protein of CNS myelin. However, PLP did not replace P0 in peripheral nervous system (PNS) myelin. To investigate the possible consequences of a PLP to P0 shift in PNS myelin, we engineered mice to express PLP instead of P0 in PNS myelin (PLP-PNS mice). PLP-PNS mice had severe neurological disabilities and died between 3 and 6 months of age. Schwann cells in sciatic nerves from PLP-PNS mice sorted axons into one-to-one relationships but failed to form myelin internodes. Mice with equal amounts of P0 and PLP had normal PNS myelination and lifespans similar to wild-type (WT) mice. When PLP was overexpressed with one copy of the P0 gene, sciatic nerves were hypomyelinated; mice displayed motor deficits, but had normal lifespans. These data support the hypothesis that while PLP can co-exist with P0 in PNS myelin, PLP cannot replace P0 as the major structural protein of PNS myelin.
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Affiliation(s)
- Xinghua Yin
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
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Mitochondrial immobilization mediated by syntaphilin facilitates survival of demyelinated axons. Proc Natl Acad Sci U S A 2014; 111:9953-8. [PMID: 24958879 DOI: 10.1073/pnas.1401155111] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 12/25/2022] Open
Abstract
Axonal degeneration is a primary cause of permanent neurological disability in individuals with the CNS demyelinating disease multiple sclerosis. Dysfunction of axonal mitochondria and imbalanced energy demand and supply are implicated in degeneration of chronically demyelinated axons. The purpose of this study was to define the roles of mitochondrial volume and distribution in axonal degeneration following acute CNS demyelination. We show that the axonal mitochondrial volume increase following acute demyelination of WT CNS axons does not occur in demyelinated axons deficient in syntaphilin, an axonal molecule that immobilizes stationary mitochondria to microtubules. These findings were supported by time-lapse imaging of WT and syntaphilin-deficient axons in vitro. When demyelinated, axons deficient in syntaphilin degenerate at a significantly greater rate than WT axons, and this degeneration can be rescued by reducing axonal electrical activity with the Na(+) channel blocker flecainide. These results support the concept that syntaphilin-mediated immobilization of mitochondria to microtubules is required for the volume increase of axonal mitochondria following acute demyelination and protects against axonal degeneration in the CNS.
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42
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Sirisi S, Folgueira M, López-Hernández T, Minieri L, Pérez-Rius C, Gaitán-Peñas H, Zang J, Martínez A, Capdevila-Nortes X, De La Villa P, Roy U, Alia A, Neuhauss S, Ferroni S, Nunes V, Estévez R, Barrallo-Gimeno A. Megalencephalic leukoencephalopathy with subcortical cysts protein 1 regulates glial surface localization of GLIALCAM from fish to humans. Hum Mol Genet 2014; 23:5069-86. [DOI: 10.1093/hmg/ddu231] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 11/12/2022] Open
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43
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Petit B, Giraudet F, Béchon C, Bardin L, Avan P, Boespflug-Tanguy O, Bégou M. Mice with a deletion of the major central myelin protein exhibit hypersensitivity to noxious thermal stimuli: involvement of central sensitization. Neurobiol Dis 2014; 65:55-68. [DOI: 10.1016/j.nbd.2014.01.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 05/17/2013] [Revised: 12/10/2013] [Accepted: 01/04/2014] [Indexed: 01/10/2023] Open
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Involvement of ER stress in dysmyelination of Pelizaeus-Merzbacher Disease with PLP1 missense mutations shown by iPSC-derived oligodendrocytes. Stem Cell Reports 2014; 2:648-61. [PMID: 24936452 PMCID: PMC4050482 DOI: 10.1016/j.stemcr.2014.03.007] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 10/08/2013] [Revised: 03/20/2014] [Accepted: 03/20/2014] [Indexed: 01/22/2023] Open
Abstract
Pelizaeus-Merzbacher disease (PMD) is a form of X-linked leukodystrophy caused by mutations in the proteolipid protein 1 (PLP1) gene. Although PLP1 proteins with missense mutations have been shown to accumulate in the rough endoplasmic reticulum (ER) in disease model animals and cell lines transfected with mutant PLP1 genes, the exact pathogenetic mechanism of PMD has not previously been clarified. In this study, we established induced pluripotent stem cells (iPSCs) from two PMD patients carrying missense mutation and differentiated them into oligodendrocytes in vitro. In the PMD iPSC-derived oligodendrocytes, mislocalization of mutant PLP1 proteins to the ER and an association between increased susceptibility to ER stress and increased numbers of apoptotic oligodendrocytes were observed. Moreover, electron microscopic analysis demonstrated drastically reduced myelin formation accompanied by abnormal ER morphology. Thus, this study demonstrates the involvement of ER stress in pathogenic dysmyelination in the oligodendrocytes of PMD patients with the PLP1 missense mutation.
Modeling Pelizaeus-Merzbacher disease (PMD) using iPSC-derived oligodendrocytes Increased ER stress involved in the apoptosis of PMD iPSC-derived oligodendrocytes Abnormal myelin structures and ER morphologies in PMD iPSC-derived oligodendrocytes Models for the pathophysiology of dysmyelinating disorders
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Boulanger JJ, Messier C. From precursors to myelinating oligodendrocytes: contribution of intrinsic and extrinsic factors to white matter plasticity in the adult brain. Neuroscience 2014; 269:343-66. [PMID: 24721734 DOI: 10.1016/j.neuroscience.2014.03.063] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 11/21/2013] [Revised: 03/28/2014] [Accepted: 03/28/2014] [Indexed: 12/21/2022]
Abstract
Oligodendrocyte precursor cells (OPC) are glial cells that metamorphose into myelinating oligodendrocytes during embryogenesis and early stages of post-natal life. OPCs continue to divide throughout adulthood and some eventually differentiate into oligodendrocytes in response to demyelinating lesions. There is growing evidence that OPCs are also involved in activity-driven de novo myelination of previously unmyelinated axons and myelin remodeling in adulthood. In this review, we summarize the interwoven factors and cascades that promote the activation, recruitment and differentiation of OPCs into myelinating oligodendrocytes in the adult brain based mostly on results found in the study of demyelinating diseases. The goal of the review was to draw a complete picture of the transformation of OPCs into mature oligodendrocytes to facilitate the study of this transformation in both the normal and diseased adult brain.
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Affiliation(s)
| | - C Messier
- School of Psychology, University of Ottawa, Canada.
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46
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Criste G, Trapp B, Dutta R. Axonal loss in multiple sclerosis: causes and mechanisms. HANDBOOK OF CLINICAL NEUROLOGY 2014; 122:101-13. [PMID: 24507515 DOI: 10.1016/b978-0-444-52001-2.00005-4] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Academic Contribution Register] [Indexed: 12/14/2022]
Abstract
Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system and the leading cause of non-traumatic neurologic disability in young adults in the United States and Europe. The disease course is variable and starts with reversible episodes of neurologic disability which transforms into continuous and irreversible neurologic decline. It is well established that loss of axons and neurons is the major cause of the progressive neurologic decline that most MS patients endure. Current hypotheses support primary inflammatory demyelination as the underlying cause of axonal loss during earlier stages in MS. The transition to progressive disease course is thought to occur when a threshold of neuronal and axonal loss is reached and the compensatory capacity of the central nervous system is surpassed. Available immunomodulatory therapies are of little benefit to MS after entering this irreversible phase of the disease. Elucidation of mechanisms that are responsible for axonal loss is therefore essential for the development of therapies directed to stop neurologic decline in MS patients. The current chapter reviews existing data on mechanisms of axonal pathology in MS.
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Affiliation(s)
- Gerson Criste
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Bruce Trapp
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA.
| | - Ranjan Dutta
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
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Beirowski B. Concepts for regulation of axon integrity by enwrapping glia. Front Cell Neurosci 2013; 7:256. [PMID: 24391540 PMCID: PMC3867696 DOI: 10.3389/fncel.2013.00256] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 09/16/2013] [Accepted: 11/25/2013] [Indexed: 12/16/2022] Open
Abstract
Long axons and their enwrapping glia (EG; Schwann cells (SCs) and oligodendrocytes (OLGs)) form a unique compound structure that serves as conduit for transport of electric and chemical information in the nervous system. The peculiar cytoarchitecture over an enormous length as well as its substantial energetic requirements make this conduit particularly susceptible to detrimental alterations. Degeneration of long axons independent of neuronal cell bodies is observed comparatively early in a range of neurodegenerative conditions as a consequence of abnormalities in SCs and OLGs . This leads to the most relevant disease symptoms and highlights the critical role that these glia have for axon integrity, but the underlying mechanisms remain elusive. The quest to understand why and how axons degenerate is now a crucial frontier in disease-oriented research. This challenge is most likely to lead to significant progress if the inextricable link between axons and their flanking glia in pathological situations is recognized. In this review I compile recent advances in our understanding of the molecular programs governing axon degeneration, and mechanisms of EG’s non-cell autonomous impact on axon-integrity. A particular focus is placed on emerging evidence suggesting that EG nurture long axons by virtue of their intimate association, release of trophic substances, and neurometabolic coupling. The correction of defects in these functions has the potential to stabilize axons in a variety of neuronal diseases in the peripheral nervous system and central nervous system (PNS and CNS).
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Affiliation(s)
- Bogdan Beirowski
- Department of Genetics, Washington University School of Medicine Saint Louis, MO, USA
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de Monasterio-Schrader P, Patzig J, Möbius W, Barrette B, Wagner TL, Kusch K, Edgar JM, Brophy PJ, Werner HB. Uncoupling of neuroinflammation from axonal degeneration in mice lacking the myelin protein tetraspanin-2. Glia 2013; 61:1832-47. [DOI: 10.1002/glia.22561] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 05/28/2013] [Revised: 07/12/2013] [Accepted: 07/16/2013] [Indexed: 12/11/2022]
Affiliation(s)
| | - Julia Patzig
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen Germany
| | - Wiebke Möbius
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB); Göttingen Germany
| | - Benoit Barrette
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen Germany
| | - Tadzio L. Wagner
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen Germany
| | - Kathrin Kusch
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen Germany
| | - Julia M. Edgar
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen Germany
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow; Bearsden Road, Glasgow G61 1QH United Kingdom
| | - Peter J. Brophy
- Centre for Neuroregeneration; University of Edinburgh; United Kingdom
| | - Hauke B. Werner
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen Germany
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49
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Autophagy promotes oligodendrocyte survival and function following dysmyelination in a long-lived myelin mutant. J Neurosci 2013; 33:8088-100. [PMID: 23637198 DOI: 10.1523/jneurosci.0233-13.2013] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 11/21/2022] Open
Abstract
The Long-Evans shaker (les) rat has a mutation in myelin basic protein that results in severe CNS dysmyelination and subsequent demyelination during development. During this time, les oligodendrocytes accumulate cytoplasmic vesicles, including lysosomes and membrane-bound organelles. However, the mechanism and functional relevance behind these oligodendrocyte abnormalities in les have not been investigated. Using high-magnification electron microscopy, we identified the accumulations in les oligodendrocytes as early and late autophagosomes. Additionally, immunohistochemistry and Western blots showed an increase in autophagy markers in les. However, autophagy did not precede the death of les oligodendrocytes. Instead, upregulating autophagy promoted membrane extensions in les oligodendrocytes in vitro. Furthermore, upregulating autophagy in les rats via intermittent fasting increased the proportion of myelinated axons as well as myelin sheath thickness in les and control rats. Overall, this study provides insight into the abnormalities described in les as well as identifying a novel mechanism that promotes the survival and function of oligodendrocytes.
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50
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Wieser GL, Gerwig UC, Adamcio B, Barrette B, Nave KA, Ehrenreich H, Goebbels S. Neuroinflammation in white matter tracts of Cnp1 mutant mice amplified by a minor brain injury. Glia 2013; 61:869-80. [PMID: 23483656 DOI: 10.1002/glia.22480] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 07/12/2012] [Accepted: 01/16/2013] [Indexed: 11/12/2022]
Abstract
Oligodendrocytes make myelin for rapid impulse propagation and contribute to the long-term survival of myelinated axons. The mechanisms by which oligodendroglial dysfunction(s) contribute to slowly progressive neurodegeneration are not well understood. Here, we demonstrate in Cnp1 mutant mice that secondary axonal degeneration in the subcortical white matter is associated with an age-dependent activation of both, innate and adaptive immune responses, including an expansion of infiltrating CD8+ T cells. While the detrimental role of lymphocytes in inherited myelin diseases is known, the role of activated microglia for the hypothetical cycle of inflammation/degeneration is unclear. We used a mild standardized cryolesion of the right parietal cortex to activate microglia at the vulnerable age of mouse puberty (postnatal day (P) 28). When applied to Cnp1 mutant mice, analyzed more than 3 months later, minor brain injury had acted as a "second hit" and significantly enhanced astrogliosis, microgliosis and axon degeneration, but not T cell infiltration. Interestingly, exacerbated neuropathological changes were also reflected by specific deterioration of working memory on top of an essentially normal basic behavior. We propose a model in which oligodendroglial dysfunctions can trigger a vicious cycle of neurodegeneration and low-grade inflammation that is amplified by nonspecific activators of the innate immune system. This interaction of genetic and environmental factors may be relevant for neuropsychiatric diseases associated with secondary neuroinflammation.
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Affiliation(s)
- Georg L Wieser
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, D-37075, Göttingen, Germany
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