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Syed Nasser N, Venugopal VK, Veenstra C, Johansson P, Rajan S, Mahajan K, Naik S, Masand R, Yadav P, Khanduri S, Singhal S, Bhargava R, Kabra U, Gupta S, Saggar K, Varaprasad B, Aggrawal K, Rao A, K S M, Dakhole A, Kelkar A, Benjamin G, Sodani V, Goyal P, Mahajan H. Age-stratified Assessment of Brain Volumetric Segmentation on the Indian Population Using Quantitative Magnetic Resonance Imaging. Clin Neuroradiol 2024; 34:541-551. [PMID: 38253891 DOI: 10.1007/s00062-023-01374-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 12/16/2023] [Indexed: 01/24/2024]
Abstract
BACKGROUND AND PURPOSE Automated methods for quantifying brain tissue volumes have gained clinical interest for their objective assessment of neurological diseases. This study aimed to establish reference curves for brain volumes and fractions in the Indian population using Synthetic MRI (SyMRI), a quantitative imaging technique providing multiple contrast-weighted images through fast postprocessing. METHODS The study included a cohort of 314 healthy individuals aged 15-65 years from multiple hospitals/centers across India. The SyMRI-quantified brain volumes and fractions, including brain parenchymal fraction (BPF), gray matter fraction (GMF), white matter fraction (WMF), and myelin. RESULTS Normative age-stratified quantification curves were created based on the obtained data. The results showed significant differences in brain volumes between the sexes, but not after normalization by intracranial volume. CONCLUSION The findings provide normative data for the Indian population and can be used for comparative analysis of brain structure values. Furthermore, our data indicate that the use of fractions rather than absolute volumes in normative curves, such as BPF, GMF, and WMF, can mitigate sex and population differences as they account for individual differences in head size or brain volume.
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Affiliation(s)
| | | | | | | | | | | | - Swati Naik
- Batra Hospital & Medical Research Centre, New Delhi, India
| | | | - Pratiksha Yadav
- Dr. D. Y. Patil Medical College, Hospital and Research Centre, Pune, India
| | | | | | | | | | | | - Kavita Saggar
- Dayanand Medical College & Hospital, Ludhiana, India
| | | | | | | | - Manoj K S
- Metro Scans and Laboratory, Thiruvananthapuram, India
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2
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Lin L, Chen Y, Dai Y, Yan Z, Zou M, Zhou Q, Qian L, Cui W, Liu M, Zhang H, Yang Z, Su S. Quantification of myelination in children with attention-deficit/hyperactivity disorder: a comparative assessment with synthetic MRI and DTI. Eur Child Adolesc Psychiatry 2024; 33:1935-1944. [PMID: 37712949 DOI: 10.1007/s00787-023-02297-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Accepted: 09/01/2023] [Indexed: 09/16/2023]
Abstract
Evaluation of myelin content is crucial for attention-deficit/hyperactivity disorder (ADHD). To estimate myelin content in ADHD based on synthetic MRI-based method and compare it with established diffusion tensor imaging (DTI) method. Fifth-nine ADHD and fifty typically developing (TD) children were recruited. Global and regional myelin content (myelin volume fraction [MVF] and myelin volume [MYV]) were assessed using SyMRI and compared with DTI metrics (fractional anisotropy and mean/radial/axial diffusivity). The relationship between significant MRI parameters and clinical variables were assessed in ADHD. No between-group differences of whole-brain myelin content were found. Compared to TDs, ADHD showed higher mean MVF in bilateral internal capsule, external capsule, corona radiata, and corpus callosum, as well as in left tapetum, left superior fronto-occipital fascicular, and right cingulum (all PFDR-corrected < 0.05). Increased MYV were found in similar regions. Abnormalities of DTI metrics were mainly in bilateral corticospinal tract. Besides, MVF in right retro lenticular part of internal capsule was negatively correlated with cancellation test scores (r = - 0.41, P = 0.002), and MYV in right posterior limb of internal capsule (r = 0.377, P = 0.040) and left superior corona radiata (r = 0.375, P = 0.041) were positively correlated with cancellation test scores in ADHD. Increased myelin content underscored the important pathway of frontostriatal tract, posterior thalamic radiation, and corpus callosum underlying ADHD, which reinforced the insights into myelin quantification and its potential role in pathophysiological mechanism and disease diagnosis. Prospectively registered trials number: ChiCTR2100048109; date: 2021-07.
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Affiliation(s)
- Liping Lin
- Department of Radiology, First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Yingqian Chen
- Department of Radiology, First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Yan Dai
- Department of Radiology, First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Zi Yan
- Department of Radiology, First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Mengsha Zou
- Department of Radiology, First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Qin Zhou
- Department of Radiology, First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Long Qian
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, China
| | - Wei Cui
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, China
| | - Meina Liu
- Department of Pediatric, First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Hongyu Zhang
- Department of Pediatric, First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Zhiyun Yang
- Department of Radiology, First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China.
| | - Shu Su
- Department of Radiology, First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China.
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3
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Peng HR, Zhang YK, Zhou JW. The Structure and Function of Glial Networks: Beyond the Neuronal Connections. Neurosci Bull 2023; 39:531-540. [PMID: 36481974 PMCID: PMC10043088 DOI: 10.1007/s12264-022-00992-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 10/27/2022] [Indexed: 12/13/2022] Open
Abstract
Glial cells, consisting of astrocytes, oligodendrocyte lineage cells, and microglia, account for >50% of the total number of cells in the mammalian brain. They play key roles in the modulation of various brain activities under physiological and pathological conditions. Although the typical morphological features and characteristic functions of these cells are well described, the organization of interconnections of the different glial cell populations and their impact on the healthy and diseased brain is not completely understood. Understanding these processes remains a profound challenge. Accumulating evidence suggests that glial cells can form highly complex interconnections with each other. The astroglial network has been well described. Oligodendrocytes and microglia may also contribute to the formation of glial networks under various circumstances. In this review, we discuss the structure and function of glial networks and their pathological relevance to central nervous system diseases. We also highlight opportunities for future research on the glial connectome.
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Affiliation(s)
- Hai-Rong Peng
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yu-Kai Zhang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jia-Wei Zhou
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China.
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100049, China.
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4
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Lee RX, Tang FR. Radiation-induced neuropathological changes in the oligodendrocyte lineage with relevant clinical manifestations and therapeutic strategies. Int J Radiat Biol 2022; 98:1519-1531. [PMID: 35311621 DOI: 10.1080/09553002.2022.2055804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE With technological advancements in radiation therapy for tumors of the central nervous system (CNS), high doses of ionizing radiation can be delivered to the tumors with improved accuracy. Despite the reduction of ionizing radiation-induced toxicity to surrounding tissues of the CNS, a wide array of side effects still occurs, particularly late-delayed changes. These alterations, such as white matter damages and neurocognitive impairments, are often debilitative and untreatable, significantly affecting the quality of life of these patients, especially children. Oligodendrocytes, a major class of glial cells, have been identified to be one of the targets of radiation toxicity and are recognized be involved in late-delayed radiation-induced neuropathological changes. These cells are responsible for forming the myelin sheaths that surround and insulate axons within the CNS. Here, the effects of ionizing radiation on the oligodendrocyte lineage as well as the common clinical manifestations resulting from radiation-induced damage to oligodendrocytes will be discussed. Potential prophylactic and therapeutic strategies against radiation-induced oligodendrocyte damage will also be considered. CONCLUSION Oligodendrocytes and oligodendrocyte progenitor cells (OPCs) are radiosensitive cells of the CNS. Here, general responses of these cells to radiation exposure have been outlined. However, several findings have not been consistent across various studies. For instance, cognitive decline in irradiated animals was observed to be accompanied by obvious demyelination or white matter changes in several studies but not in others. Hence, further studies have to be conducted to elucidate the level of contribution of the oligodendrocyte lineage to the development of late-delayed effects of radiation exposure, as well as to classify the dose and brain region-specific responses of the oligodendrocyte lineage to radiation. Several potential therapeutic approaches against late-delayed changes have been discussed, such as the transplantation of OPCs into irradiated regions and implementation of exercise. Many of these approaches show promising results. Further elucidation of the mechanisms involved in radiation-induced death of oligodendrocytes and OPCs would certainly aid in the development of novel protective and therapeutic strategies against the late-delayed effects of radiation.
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Affiliation(s)
- Rui Xue Lee
- Radiation Physiology Laboratory, Singapore Nuclear Research and Safety Initiative, National University of Singapore, Singapore, Singapore
| | - Feng Ru Tang
- Radiation Physiology Laboratory, Singapore Nuclear Research and Safety Initiative, National University of Singapore, Singapore, Singapore
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Yao K, Cao L, Ding H, Gao Y, Li T, Wang G, Zhang J. Increasing Aspartoacylase in the Central Amygdala: The Common Mechanism of Gastroprotective Effects of Monoamine-Based Antidepressants Against Stress. Front Pharmacol 2022; 13:823291. [PMID: 35281914 PMCID: PMC8914169 DOI: 10.3389/fphar.2022.823291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 01/19/2022] [Indexed: 11/17/2022] Open
Abstract
Monoamine-based antidepressants can prophylactically protect against stress-induced gastric ulcers. Although the central nucleus of amygdala (CeA) has been shown to modulate the severity of stress ulcers, little is known about the molecular mechanisms underlying the gastroprotective effect of this kind of drugs. Here, we first used proton magnetic resonance spectroscopy, a non-invasive tool, to explore the change of neurometabolites of the CeA of rats pretreated with the duloxetine of selective serotonin-norepinephrine reuptake inhibitors during 6 h of water-immersion restraint stress (WIRS). Duloxetine decreased N-acetyl-aspartate/creatine ratio (NAA/creatine) in CeA after WIRS, which was paralleled by the amelioration of gastric lesions. Meanwhile, the gastric ulcer index was negatively correlated with reduced NAA/creatine. Furthermore, the intra-CeA infusion of NAA aggravated WIRS-induced gastric mucosa damage, which suggested the crucial role of reduced NAA. Western blotting was performed to identify the specific enzymes responsible for the change of the contents of NAA at 0.5 h/3 h/6 h after WIRS, considering the preventative gastric protection of duloxetine. The NAA-catabolizing enzyme aspartoacylase (ASPA) was the only enzyme downregulated by 0.5 h WIRS and upregulated by duloxetine. Moreover, overexpressing ASPA in CeA alleviated stress ulcers. Additionally, all of the other three monoamine-based antidepressants, the fluoxetine of selective serotonin reuptake inhibitors, the amitriptyline of tricyclic agents, and the moclobemide of MAOs, increased ASPA expression in CeA. Together, these results indicate that increasing ASPA to hydrolyze NAA in CeA is a common mechanism of gastroprotective effects against stress exerted by monoamine-based antidepressants, and ASPA is a shared target more than monoamine regulation for this kind of drugs.
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Affiliation(s)
- Kaiyun Yao
- Department of Pharmacology, Beijing, China
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Linyu Cao
- Department of Pharmacology, Beijing, China
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hongwan Ding
- Department of Pharmacology, Beijing, China
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yinge Gao
- Department of Pharmacology, Beijing, China
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Tiegang Li
- Department of Pharmacology, Beijing, China
| | - Guibin Wang
- Department of Pharmacology, Beijing, China
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- *Correspondence: Guibin Wang, ; Jianjun Zhang,
| | - Jianjun Zhang
- Department of Pharmacology, Beijing, China
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- *Correspondence: Guibin Wang, ; Jianjun Zhang,
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6
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Murugappan SK, Hasan M, Lei Z, Iqbal Z, Ramkrishnan AS, Wong HY, Li Y. Trigeminal neuropathy causes hypomyelination in the anterior cingulate cortex, disrupts the synchrony of neural circuitry, and impairs decision-making in male rats. J Neurosci Res 2021; 99:2721-2742. [PMID: 34323312 PMCID: PMC8596863 DOI: 10.1002/jnr.24903] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 05/25/2021] [Accepted: 05/26/2021] [Indexed: 12/17/2022]
Abstract
Infraorbital nerve‐chronic constriction injury (ION‐CCI) has become the most popular chronic trigeminal neuropathic pain (TNP) injury animal model which causes prolonged mechanical allodynia. Accumulative evidence suggests that TNP interferes with cognitive functions, however the underlying mechanisms are not known. The aim of this study was to investigate decision‐making performance as well as synaptic and large‐scale neural synchronized alterations in the spinal trigeminal nucleus (SpV) circuitry and anterior cingulate cortex (ACC) neural circuitry in male rats with TNP. Rat gambling task showed that ION‐CCI led to decrease the proportion of good decision makers and increase the proportion of poor decision makers. Electrophysiological recordings showed long‐lasting synaptic potentiation of local field potential in the trigeminal ganglia‐SpV caudalis (SpVc) synapses in TNP rats. In this study, TNP led to disruption of ACC spike timing and basolateral amygdala (BLA) theta oscillation associated with suppressed synchronization of theta oscillation between the BLA and ACC, indicating reduced neuronal communications. Myelination is critical for information flow between brain regions, and myelin plasticity is an important feature for learning. Neural activity in the cortical regions impacts myelination by regulating oligodendrocyte (OL) proliferation, differentiation, and myelin formation. We characterized newly formed oligodendrocyte progenitor cells, and mature OLs are reduced in TNP and are associated with reduced myelin strength in the ACC region. The functional disturbances in the BLA‐ACC neural circuitry is pathologically associated with the myelin defects in the ACC region which may be relevant causes for the deficits in decision‐making in chronic TNP state.
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Affiliation(s)
- Suresh K Murugappan
- Department of Biomedical Sciences, College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong
| | - Mahadi Hasan
- Department of Biomedical Sciences, College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong.,Department of Neuroscience, College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong
| | - Zhuogui Lei
- Department of Biomedical Sciences, College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong.,Department of Neuroscience, College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong
| | - Zafar Iqbal
- Department of Biomedical Sciences, College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong.,Department of Neuroscience, College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong.,Centre for Regenerative Medicine and Health, Hong Kong Institute of Science & Innovation, Chinese Academy of Sciences, Hong Kong SAR, P.R. China
| | - Aruna S Ramkrishnan
- Department of Biomedical Sciences, College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong.,Department of Neuroscience, College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong
| | - Heung Y Wong
- Department of Biomedical Sciences, College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong.,Department of Neuroscience, College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong.,Centre for Regenerative Medicine and Health, Hong Kong Institute of Science & Innovation, Chinese Academy of Sciences, Hong Kong SAR, P.R. China
| | - Ying Li
- Department of Biomedical Sciences, College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong.,Department of Neuroscience, College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong.,Centre for Regenerative Medicine and Health, Hong Kong Institute of Science & Innovation, Chinese Academy of Sciences, Hong Kong SAR, P.R. China.,Centre for Biosystems, Neuroscience, and Nanotechnology, City University of Hong Kong, Kowloon, Hong Kong
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Wang M, Kleele T, Xiao Y, Plucinska G, Avramopoulos P, Engelhardt S, Schwab MH, Kneussel M, Czopka T, Sherman DL, Brophy PJ, Misgeld T, Brill MS. Completion of neuronal remodeling prompts myelination along developing motor axon branches. J Cell Biol 2021; 220:e201911114. [PMID: 33538762 PMCID: PMC7868780 DOI: 10.1083/jcb.201911114] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 11/20/2020] [Accepted: 01/04/2021] [Indexed: 12/20/2022] Open
Abstract
Neuronal remodeling and myelination are two fundamental processes during neurodevelopment. How they influence each other remains largely unknown, even though their coordinated execution is critical for circuit function and often disrupted in neuropsychiatric disorders. It is unclear whether myelination stabilizes axon branches during remodeling or whether ongoing remodeling delays myelination. By modulating synaptic transmission, cytoskeletal dynamics, and axonal transport in mouse motor axons, we show that local axon remodeling delays myelination onset and node formation. Conversely, glial differentiation does not determine the outcome of axon remodeling. Delayed myelination is not due to a limited supply of structural components of the axon-glial unit but rather is triggered by increased transport of signaling factors that initiate myelination, such as neuregulin. Further, transport of promyelinating signals is regulated via local cytoskeletal maturation related to activity-dependent competition. Our study reveals an axon branch-specific fine-tuning mechanism that locally coordinates axon remodeling and myelination.
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Affiliation(s)
- Mengzhe Wang
- Institute of Neuronal Cell Biology, Technische Universität München, Munich, Germany
| | - Tatjana Kleele
- Institute of Neuronal Cell Biology, Technische Universität München, Munich, Germany
| | - Yan Xiao
- Institute of Neuronal Cell Biology, Technische Universität München, Munich, Germany
| | - Gabriela Plucinska
- Institute of Neuronal Cell Biology, Technische Universität München, Munich, Germany
| | - Petros Avramopoulos
- Institute of Pharmacology and Toxicology, Technische Universität München, Munich, Germany
- German Center for Cardiovascular Research (DZHK), partner site Munich Heart Alliance, Munich, Germany
| | - Stefan Engelhardt
- Institute of Pharmacology and Toxicology, Technische Universität München, Munich, Germany
- German Center for Cardiovascular Research (DZHK), partner site Munich Heart Alliance, Munich, Germany
| | - Markus H. Schwab
- Department of Cellular Neurophysiology, Hannover Medical School, Hannover, Germany
| | - Matthias Kneussel
- University Medical Center Hamburg-Eppendorf, Center for Molecular Neurobiology (ZMNH), Institute for Molecular Neurogenetics, Hamburg, Germany
| | - Tim Czopka
- Institute of Neuronal Cell Biology, Technische Universität München, Munich, Germany
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
- Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
| | - Diane L. Sherman
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Peter J. Brophy
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Thomas Misgeld
- Institute of Neuronal Cell Biology, Technische Universität München, Munich, Germany
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
| | - Monika S. Brill
- Institute of Neuronal Cell Biology, Technische Universität München, Munich, Germany
- Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
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Tachibana Y, Hagiwara A, Hori M, Kershaw J, Nakazawa M, Omatsu T, Kishimoto R, Yokoyama K, Hattori N, Aoki S, Higashi T, Obata T. The Utility of a Convolutional Neural Network for Generating a Myelin Volume Index Map from Rapid Simultaneous Relaxometry Imaging. Magn Reson Med Sci 2020; 19:324-332. [PMID: 31902906 PMCID: PMC7809139 DOI: 10.2463/mrms.mp.2019-0075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Purpose: A current algorithm to obtain a synthetic myelin volume fraction map (SyMVF) from rapid simultaneous relaxometry imaging (RSRI) has a potential problem, that it does not incorporate information from surrounding pixels. The purpose of this study was to develop a method that utilizes a convolutional neural network (CNN) to overcome this problem. Methods: RSRI and magnetization transfer images from 20 healthy volunteers were included. A CNN was trained to reconstruct RSRI-related metric maps into a myelin volume-related index (generated myelin volume index: GenMVI) map using the MVI map calculated from magnetization transfer images (MTMVI) as reference. The SyMVF and GenMVI maps were statistically compared by testing how well they correlated with the MTMVI map. The correlations were evaluated based on: (i) averaged values obtained from 164 atlas-based ROIs, and (ii) pixel-based comparison for ROIs defined in four different tissue types (cortical and subcortical gray matter, white matter, and whole brain). Results: For atlas-based ROIs, the overall correlation with the MTMVI map was higher for the GenMVI map than for the SyMVF map. In the pixel-based comparison, correlation with the MTMVI map was stronger for the GenMVI map than for the SyMVF map, and the difference in the distribution for the volunteers was significant (Wilcoxon sign-rank test, P < 0.001) in all tissue types. Conclusion: The proposed method is useful, as it can incorporate more specific information about local tissue properties than the existing method. However, clinical validation is necessary.
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Affiliation(s)
- Yasuhiko Tachibana
- Applied MRI Research, Department of Molecular Imaging and Theranostics, National Institute of Radiological Sciences.,Department of Radiology, Juntendo University School of Medicine
| | - Akifumi Hagiwara
- Department of Radiology, Juntendo University School of Medicine.,Department of Radiology, Graduate School of Medicine, The University of Tokyo
| | - Masaaki Hori
- Department of Radiology, Juntendo University School of Medicine
| | - Jeff Kershaw
- Applied MRI Research, Department of Molecular Imaging and Theranostics, National Institute of Radiological Sciences
| | - Misaki Nakazawa
- Department of Radiology, Juntendo University School of Medicine
| | - Tokuhiko Omatsu
- Applied MRI Research, Department of Molecular Imaging and Theranostics, National Institute of Radiological Sciences
| | - Riwa Kishimoto
- Applied MRI Research, Department of Molecular Imaging and Theranostics, National Institute of Radiological Sciences
| | | | | | - Shigeki Aoki
- Department of Radiology, Juntendo University School of Medicine
| | - Tatsuya Higashi
- Department of Molecular Imaging and Theranostics, National Institute of Radiological Sciences
| | - Takayuki Obata
- Applied MRI Research, Department of Molecular Imaging and Theranostics, National Institute of Radiological Sciences.,Department of Molecular Imaging and Theranostics, National Institute of Radiological Sciences
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9
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Park SH, Lefebvre J. Synchronization and resilience in the Kuramoto white matter network model with adaptive state-dependent delays. JOURNAL OF MATHEMATICAL NEUROSCIENCE 2020; 10:16. [PMID: 32936367 PMCID: PMC7494726 DOI: 10.1186/s13408-020-00091-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 08/25/2020] [Indexed: 06/11/2023]
Abstract
White matter pathways form a complex network of myelinated axons that regulate signal transmission in the nervous system and play a key role in behaviour and cognition. Recent evidence reveals that white matter networks are adaptive and that myelin remodels itself in an activity-dependent way, during both developmental stages and later on through behaviour and learning. As a result, axonal conduction delays continuously adjust in order to regulate the timing of neural signals propagating between different brain areas. This delay plasticity mechanism has yet to be integrated in computational neural models, where conduction delays are oftentimes constant or simply ignored. As a first approach to adaptive white matter remodeling, we modified the canonical Kuramoto model by enabling all connections with adaptive, phase-dependent delays. We analyzed the equilibria and stability of this system, and applied our results to two-oscillator and large-dimensional networks. Our joint mathematical and numerical analysis demonstrates that plastic delays act as a stabilizing mechanism promoting the network's ability to maintain synchronous activity. Our work also shows that global synchronization is more resilient to perturbations and injury towards network architecture. Our results provide key insights about the analysis and potential significance of activity-dependent myelination in large-scale brain synchrony.
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Affiliation(s)
- Seong Hyun Park
- University of Toronto, St. George, 40 St. George St., M5S 2E4, Toronto, Canada.
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, M5T 2S8, Toronto, Canada.
| | - Jérémie Lefebvre
- University of Toronto, St. George, 40 St. George St., M5S 2E4, Toronto, Canada
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, M5T 2S8, Toronto, Canada
- University of Ottawa, Gendron Hall, 30 Marie Curie, K1N 6N5, Ottawa, Canada
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10
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Wilton DK, Stevens B. The contribution of glial cells to Huntington's disease pathogenesis. Neurobiol Dis 2020; 143:104963. [PMID: 32593752 DOI: 10.1016/j.nbd.2020.104963] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 05/07/2020] [Accepted: 06/10/2020] [Indexed: 12/20/2022] Open
Abstract
Glial cells play critical roles in the normal development and function of neural circuits, but in many neurodegenerative diseases, they become dysregulated and may contribute to the development of brain pathology. In Huntington's disease (HD), glial cells both lose normal functions and gain neuropathic phenotypes. In addition, cell-autonomous dysfunction elicited by mutant huntingtin (mHTT) expression in specific glial cell types is sufficient to induce both pathology and Huntington's disease-related impairments in motor and cognitive performance, suggesting that these cells may drive the development of certain aspects of Huntington's disease pathogenesis. In support of this imaging studies in pre-symptomatic HD patients and work on mouse models have suggested that glial cell dysfunction occurs at a very early stage of the disease, prior to the onset of motor and cognitive deficits. Furthermore, selectively ablating mHTT from specific glial cells or correcting for HD-induced changes in their transcriptional profile rescues some HD-related phenotypes, demonstrating the potential of targeting these cells for therapeutic intervention. Here we review emerging research focused on understanding the involvement of different glial cell types in specific aspects of HD pathogenesis. This work is providing new insight into how HD impacts biological functions of glial cells in the healthy brain as well as how HD induced dysfunction in these cells might change the way they integrate into biological circuits.
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Affiliation(s)
- Daniel K Wilton
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Beth Stevens
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Stanley Center, Broad Institute, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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11
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White matter injury and neurodevelopmental disabilities: A cross-disease (dis)connection. Prog Neurobiol 2020; 193:101845. [PMID: 32505757 DOI: 10.1016/j.pneurobio.2020.101845] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 05/19/2020] [Accepted: 06/01/2020] [Indexed: 12/13/2022]
Abstract
White matter (WM) injury, once known primarily in preterm newborns, is emerging in its non-focal (diffused), non-necrotic form as a critical component of subtle brain injuries in many early-life diseases like prematurity, intrauterine growth restriction, congenital heart defects, and hypoxic-ischemic encephalopathy. While advances in medical techniques have reduced the number of severe outcomes, the incidence of tardive impairments in complex cognitive functions or psychopathology remains high, with lifelong detrimental effects. The importance of WM in coordinating neuronal assemblies firing and neural groups synchronizing within multiple frequency bands through myelination, even mild alterations in WM structure, may interfere with the cognitive performance that increasing social and learning demands would exploit tardively during children growth. This phenomenon may contribute to explaining longitudinally the high incidence of late-appearing impairments that affect children with a history of perinatal insults. Furthermore, WM abnormalities have been highlighted in several neuropsychiatric disorders, such as autism and schizophrenia. In this review, we gather and organize evidence on how diffused WM injuries contribute to neurodevelopmental disorders through different perinatal diseases and insults. An insight into a possible common, cross-disease, mechanism, neuroimaging and monitoring, biomarkers, and neuroprotective strategies will also be presented.
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12
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Dietz AG, Goldman SA, Nedergaard M. Glial cells in schizophrenia: a unified hypothesis. Lancet Psychiatry 2020; 7:272-281. [PMID: 31704113 PMCID: PMC7267935 DOI: 10.1016/s2215-0366(19)30302-5] [Citation(s) in RCA: 121] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 07/23/2019] [Accepted: 07/24/2019] [Indexed: 12/11/2022]
Abstract
The cellular neurobiology of schizophrenia remains poorly understood. We discuss neuroimaging studies, pathological findings, and experimental work supporting the idea that glial cells might contribute to the development of schizophrenia. Experimental studies suggest that abnormalities in the differentiation competence of glial progenitor cells lead to failure in the morphological and functional maturation of oligodendrocytes and astrocytes. We propose that immune activation of microglial cells during development, superimposed upon genetic risk factors, could contribute to defective differentiation competence of glial progenitor cells. The resulting hypomyelination and disrupted white matter integrity might contribute to transmission desynchronisation and dysconnectivity, whereas the failure of astrocytic differentiation results in abnormal glial coverage and support of synapses. The delayed and deficient maturation of astrocytes might, in parallel, lead to disruption of glutamatergic, potassium, and neuromodulatory homoeostasis, resulting in dysregulated synaptic transmission. By highlighting a role for glial cells in schizophrenia, these studies potentially point to new mechanisms for disease modification.
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Affiliation(s)
- Andrea G Dietz
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Steven A Goldman
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, USA.
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, USA
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13
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Preservation of a remote fear memory requires new myelin formation. Nat Neurosci 2020; 23:487-499. [PMID: 32042175 DOI: 10.1038/s41593-019-0582-1] [Citation(s) in RCA: 195] [Impact Index Per Article: 48.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 12/20/2019] [Indexed: 12/18/2022]
Abstract
Experience-dependent myelination is hypothesized to shape neural circuit function and subsequent behavioral output. Using a contextual fear memory task in mice, we demonstrate that fear learning induces oligodendrocyte precursor cells to proliferate and differentiate into myelinating oligodendrocytes in the medial prefrontal cortex. Transgenic animals that cannot form new myelin exhibit deficient remote, but not recent, fear memory recall. Recording population calcium dynamics by fiber photometry, we observe that the neuronal response to conditioned context cues evolves over time in the medial prefrontal cortex, but not in animals that cannot form new myelin. Finally, we demonstrate that pharmacological induction of new myelin formation with clemastine fumarate improves remote memory recall and promotes fear generalization. Thus, bidirectional manipulation of myelin plasticity functionally affects behavior and neurophysiology, which suggests that neural activity during fear learning instructs the formation of new myelin, which in turn supports the consolidation and/or retrieval of remote fear memories.
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14
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Myelin Measurement Using Quantitative Magnetic Resonance Imaging: A Correlation Study Comparing Various Imaging Techniques in Patients with Multiple Sclerosis. Cells 2020; 9:cells9020393. [PMID: 32046340 PMCID: PMC7072333 DOI: 10.3390/cells9020393] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 01/28/2020] [Accepted: 02/06/2020] [Indexed: 12/13/2022] Open
Abstract
Evaluation of myelin by magnetic resonance imaging (MRI) is a difficult challenge, but holds promise in demyelinating diseases, such as multiple sclerosis (MS). Although multiple techniques have been developed, no gold standard has been established. This study aims to evaluate the correlation between synthetic MRI myelin volume fraction (SyMRIMVF) and myelin fraction estimated by other techniques, i.e., magnetization transfer saturation (MTsat), T1-weighted images divided by T2-weighted images (T1w/T2w), and radial diffusivity (RD) in patients with MS. We also compared the sensitivities of these techniques for detecting MS-related myelin damage. SyMRIMVF, MTsat, T1w/T2w, and RD were averaged on plaque, periplaque white matter, and normal-appearing white matter (NAWM). Pairwise correlation was calculated using Spearman’s correlation analysis. For all segmented regions, strong correlations were found between SyMRIMVF and T1w/T2w (Rho = 0.89), MTsat (Rho = 0.82), or RD (Rho = −0.75). For each technique, the average estimated myelin differed significantly among regions, but the percentage change of NAWM from both periplaque white matter and plaque were highest in SyMRIMVF. SyMRIMVF might be suitable for myelin evaluation in MS patients, with relevant results as compared to other well-studied techniques. Moreover, it presented better sensitivity for the detection of the difference between plaque or periplaque white matter and NAWM.
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15
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Wong M. The role of glia in epilepsy, intellectual disability, and other neurodevelopmental disorders in tuberous sclerosis complex. J Neurodev Disord 2019; 11:30. [PMID: 31838997 PMCID: PMC6913020 DOI: 10.1186/s11689-019-9289-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 11/11/2019] [Indexed: 01/12/2023] Open
Abstract
Background Tuberous sclerosis complex (TSC) is a genetic disorder characterized by severe neurological manifestations, including epilepsy, intellectual disability, autism, and a range of other behavioral and psychiatric symptoms, collectively referred to as TSC-associated neuropsychiatric disorders (TAND). Various tumors and hamartomas affecting different organs are the pathological hallmarks of the disease, especially cortical tubers of the brain, but specific cellular and molecular abnormalities, such as involving the mechanistic target of rapamycin (mTOR) pathway, have been identified that also cause or contribute to neurological manifestations of TSC independent of gross structural lesions. In particular, while neurons are immediate mediators of neurological symptoms, different types of glial cells have been increasingly recognized to play important roles in the phenotypes of TSC. Main body This review summarizes the literature supporting glial dysfunction from both mouse models and clinical studies of TSC. In particular, evidence for the role of astrocytes, microglia, and oligodendrocytes in the pathophysiology of epilepsy and TAND in TSC is analyzed. Therapeutic implications of targeting glia cells in developing novel treatments for the neurological manifestations of TSC are also considered. Conclusions Different types of glial cells have both cell autonomous effects and interactions with neurons and other cells that are involved in the pathophysiology of the neurological phenotype of TSC. Targeting glial-mediated mechanisms may represent a novel therapeutic approach for epilepsy and TAND in TSC patients.
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Affiliation(s)
- Michael Wong
- Department of Neurology and the Hope Center for Neurological Disorders, Washington University School of Medicine, 660 South Euclid Avenue, Box 8111, St. Louis, MO, 63110, USA.
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16
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Chen X, Wang F, Gan J, Zhang Z, Liang X, Li T, Huang N, Zhao X, Mei F, Xiao L. Myelin Deficits Caused by Olig2 Deficiency Lead to Cognitive Dysfunction and Increase Vulnerability to Social Withdrawal in Adult Mice. Neurosci Bull 2019; 36:419-426. [PMID: 31758330 DOI: 10.1007/s12264-019-00449-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 08/27/2019] [Indexed: 01/25/2023] Open
Abstract
Oligodendrocyte (OL) and myelin development are crucial for network integration and are associated with higher brain functions. Accumulating evidence has demonstrated structural and functional impairment of OLs and myelin in serious mental illnesses. However, whether these deficits contribute to the brain dysfunction or pathogenesis of such diseases still lacks direct evidence. In this study, we conditionally deleted Olig2 in oligodendroglial lineage cells (Olig2 cKO) and screened the behavioral changes in adult mice. We found that Olig2 ablation impaired myelin development, which further resulted in severe hypomyelination in the anterior cingulate cortex. Strikingly, Olig2 cKO mice exhibited an anxious phenotype, aberrant responses to stress, and cognitive deficits. Moreover, Olig2 cKO mice showed increased vulnerability to social avoidance under the mild stress of social isolation. Together, these results indicate that developmental deficits in OL and myelin lead to cognitive impairment and increase the risk of phenotypes reminiscent of mental illnesses.
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Affiliation(s)
- Xianjun Chen
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Army Medical University (Third Military Medical University), Chongqing, 400038, China.,Department of Psychiatry, Mental Diseases Prevention and Treatment Institute of The People's Liberation Army (PLA), 988 Hospital of Joint Logistic Support Force of PLA, Jiaozuo, 454003, China
| | - Fei Wang
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Army Medical University (Third Military Medical University), Chongqing, 400038, China
| | - Jingli Gan
- Department of Psychiatry, Mental Diseases Prevention and Treatment Institute of The People's Liberation Army (PLA), 988 Hospital of Joint Logistic Support Force of PLA, Jiaozuo, 454003, China
| | - Zhonghua Zhang
- Department of Psychiatry, Mental Diseases Prevention and Treatment Institute of The People's Liberation Army (PLA), 988 Hospital of Joint Logistic Support Force of PLA, Jiaozuo, 454003, China
| | - Xuejun Liang
- Department of Psychiatry, Mental Diseases Prevention and Treatment Institute of The People's Liberation Army (PLA), 988 Hospital of Joint Logistic Support Force of PLA, Jiaozuo, 454003, China
| | - Tao Li
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Army Medical University (Third Military Medical University), Chongqing, 400038, China
| | - Nanxin Huang
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Army Medical University (Third Military Medical University), Chongqing, 400038, China
| | - Xiaofeng Zhao
- Institute of Life Sciences, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China
| | - Feng Mei
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Army Medical University (Third Military Medical University), Chongqing, 400038, China
| | - Lan Xiao
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Army Medical University (Third Military Medical University), Chongqing, 400038, China.
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17
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Detrimental Impact of Energy Drink Compounds on Developing Oligodendrocytes and Neurons. Cells 2019; 8:cells8111381. [PMID: 31684159 PMCID: PMC6912672 DOI: 10.3390/cells8111381] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 10/30/2019] [Accepted: 10/31/2019] [Indexed: 12/12/2022] Open
Abstract
The consumption of energy drinks is continuously rising, particularly in children and adolescents. While risks for adverse health effects, like arrhythmia, have been described, effects on neural cells remain elusive. Considering that neurodevelopmental processes like myelination and neuronal network formation peak in childhood and adolescence we hypothesized that developing oligodendrocytes and neurons are particularly vulnerable to main energy drink components. Immature oligodendrocytes and hippocampal neurons were isolated from P0-P1 Wistar rats and were incubated with 0.3 mg/mL caffeine and 4 mg/mL taurine alone or in combination for 24 h. Analysis was performed immediately after treatment or after additional three days under differentiating conditions for oligodendrocytes and standard culture for neurons. Oligodendrocyte degeneration, proliferation, and differentiation were assessed via immunocytochemistry and immunoblotting. Neuronal integrity was investigated following immunocytochemistry by analysis of dendrite outgrowth and axonal morphology. Caffeine and taurine induced an increased degeneration and inhibited proliferation of immature oligodendrocytes accompanied by a decreased differentiation capacity. Moreover, dendritic branching and axonal integrity of hippocampal neurons were negatively affected by caffeine and taurine treatment. The negative impact of caffeine and taurine on developing oligodendrocytes and disturbed neuronal morphology indicates a high risk for disturbed neurodevelopment in children and adolescents by excessive energy drink consumption.
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18
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Stadelmann C, Timmler S, Barrantes-Freer A, Simons M. Myelin in the Central Nervous System: Structure, Function, and Pathology. Physiol Rev 2019; 99:1381-1431. [PMID: 31066630 DOI: 10.1152/physrev.00031.2018] [Citation(s) in RCA: 292] [Impact Index Per Article: 58.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Oligodendrocytes generate multiple layers of myelin membrane around axons of the central nervous system to enable fast and efficient nerve conduction. Until recently, saltatory nerve conduction was considered the only purpose of myelin, but it is now clear that myelin has more functions. In fact, myelinating oligodendrocytes are embedded in a vast network of interconnected glial and neuronal cells, and increasing evidence supports an active role of oligodendrocytes within this assembly, for example, by providing metabolic support to neurons, by regulating ion and water homeostasis, and by adapting to activity-dependent neuronal signals. The molecular complexity governing these interactions requires an in-depth molecular understanding of how oligodendrocytes and axons interact and how they generate, maintain, and remodel their myelin sheaths. This review deals with the biology of myelin, the expanded relationship of myelin with its underlying axons and the neighboring cells, and its disturbances in various diseases such as multiple sclerosis, acute disseminated encephalomyelitis, and neuromyelitis optica spectrum disorders. Furthermore, we will highlight how specific interactions between astrocytes, oligodendrocytes, and microglia contribute to demyelination in hereditary white matter pathologies.
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Affiliation(s)
- Christine Stadelmann
- Institute of Neuropathology, University Medical Center Göttingen , Göttingen , Germany ; Institute of Neuronal Cell Biology, Technical University Munich , Munich , Germany ; German Center for Neurodegenerative Diseases (DZNE), Munich , Germany ; Department of Neuropathology, University Medical Center Leipzig , Leipzig , Germany ; Munich Cluster of Systems Neurology (SyNergy), Munich , Germany ; and Max Planck Institute of Experimental Medicine, Göttingen , Germany
| | - Sebastian Timmler
- Institute of Neuropathology, University Medical Center Göttingen , Göttingen , Germany ; Institute of Neuronal Cell Biology, Technical University Munich , Munich , Germany ; German Center for Neurodegenerative Diseases (DZNE), Munich , Germany ; Department of Neuropathology, University Medical Center Leipzig , Leipzig , Germany ; Munich Cluster of Systems Neurology (SyNergy), Munich , Germany ; and Max Planck Institute of Experimental Medicine, Göttingen , Germany
| | - Alonso Barrantes-Freer
- Institute of Neuropathology, University Medical Center Göttingen , Göttingen , Germany ; Institute of Neuronal Cell Biology, Technical University Munich , Munich , Germany ; German Center for Neurodegenerative Diseases (DZNE), Munich , Germany ; Department of Neuropathology, University Medical Center Leipzig , Leipzig , Germany ; Munich Cluster of Systems Neurology (SyNergy), Munich , Germany ; and Max Planck Institute of Experimental Medicine, Göttingen , Germany
| | - Mikael Simons
- Institute of Neuropathology, University Medical Center Göttingen , Göttingen , Germany ; Institute of Neuronal Cell Biology, Technical University Munich , Munich , Germany ; German Center for Neurodegenerative Diseases (DZNE), Munich , Germany ; Department of Neuropathology, University Medical Center Leipzig , Leipzig , Germany ; Munich Cluster of Systems Neurology (SyNergy), Munich , Germany ; and Max Planck Institute of Experimental Medicine, Göttingen , Germany
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19
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Abstract
Structural plasticity in the myelinated infrastructure of the nervous system has come to light. Although an innate program of myelin development proceeds independent of nervous system activity, a second mode of myelination exists in which activity-dependent, plastic changes in myelin-forming cells influence myelin structure and neurological function. These complementary and possibly temporally overlapping activity-independent and activity-dependent modes of myelination crystallize in a model of experience-modulated myelin development and plasticity with broad implications for neurological function. In this article, I consider the contributions of myelin to neural circuit function, the dynamic influences of experience on myelin microstructure, and the role that plasticity of myelin may play in cognition.
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Affiliation(s)
- Michelle Monje
- Department of Neurology, Stanford University, Stanford, California 94305, USA;
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20
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Timmler S, Simons M. Grey matter myelination. Glia 2019; 67:2063-2070. [PMID: 30860619 DOI: 10.1002/glia.23614] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 02/21/2019] [Accepted: 02/25/2019] [Indexed: 11/11/2022]
Abstract
There is now increasing evidence that myelin is not only generated early in development, but also during adulthood possibly contributing to lifelong plasticity of the brain. In particular, human cortical areas responsible for the highest cognitive functions seem to require decades until they have reached their maximal amount of myelination. Currently, we know very little about the mechanisms and the functions of grey matter myelination. In this emerging field key questions await to be addressed: How long does myelination last in humans? How is grey matter myelination regulated? What is the function of myelin in the grey matter? Does grey matter myelination limit and/or promote neuronal plasticity? Finding answers to these questions will be important for our understanding of normal, but also abnormal cortex function in a number of neurological and psychiatric diseases.
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Affiliation(s)
- Sebastian Timmler
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany.,Institute of Neuronal Cell Biology, German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Mikael Simons
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany.,Institute of Neuronal Cell Biology, German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Munich Cluster of Systems Neurology (SyNergy), Munich, Germany.,Max Planck Institute of Experimental Medicine, Göttingen, Germany
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21
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Region- and Cell Type-Specific Facilitation of Synaptic Function at Destination Synapses Induced by Oligodendrocyte Depolarization. J Neurosci 2019; 39:4036-4050. [PMID: 30862665 DOI: 10.1523/jneurosci.1619-18.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 03/01/2019] [Accepted: 03/06/2019] [Indexed: 11/21/2022] Open
Abstract
The axonal conduction of action potentials affects the absolute time it takes to transmit nerve impulses as well as temporal summation at destination synapses. At the physiological level, oligodendrocyte depolarization facilitates axonal conduction along myelinated fibers in the hippocampus; however, the functional significance of this facilitation is largely unknown. In this study, we examined the physiology of the facilitation of axonal conduction by investigating the changes in synaptic responses at destination synapses using male and female mice in which channelrhodopsin-2 expression was restricted to oligodendrocytes. The subiculum, one of the projection areas of the examined axons at the alveus of the hippocampus, is divided into three regions (proximal, mid, and distal) and contains two types of principal neurons: regular firing and bursting pyramidal cells. We found a significant increase in excitatory synaptic responses following optogenetic oligodendrocyte depolarization in bursting neurons at two of the three regions, but not in regular firing neurons at any region. The long-term potentiation (LTP) induced by theta burst stimulation at the synapses showing a significant increase was also enhanced after oligodendrocyte depolarization. Conversely, the reduction of oligodendrocyte depolarization during theta burst stimulation, which was achieved by photostimulation of archaerhodopsin-T expressed selectively on oligodendrocytes, reduced the magnitude of LTP. These results show that oligodendrocyte depolarization contributes to the fine control of synaptic activity between the axons they myelinate and targets subicular cells in a region- and cell type-specific manner, and suggest that oligodendrocyte depolarization during conditioning of stimuli is involved in the induction of LTP.SIGNIFICANCE STATEMENT All activity in the nervous system depends on the propagation of action potentials. Changes in the axonal conduction of action potentials influence the timing of synaptic transmission and information processing in neural circuits. At the physiological level, oligodendrocyte depolarization facilitates axonal conduction along myelinated fibers. In this study, we investigated the functional significance of the facilitation of axonal conduction induced by physiological oligodendrocyte depolarization. Using optogenetics and electrophysiological recordings, we demonstrated that oligodendrocyte depolarization in mice expressing channelrhodopsin-2 on oligodendrocytes increased excitatory synaptic responses and enhanced the induction of long-term potentiation at destination synapses in a region- and cell type-specific manner. This facilitation may have a hitherto unappreciated influence on the transfer of information between regions in the nervous system.
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22
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Yamazaki Y. Oligodendrocyte Physiology Modulating Axonal Excitability and Nerve Conduction. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1190:123-144. [PMID: 31760642 DOI: 10.1007/978-981-32-9636-7_9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Oligodendrocytes enable saltatory conduction by forming a myelin sheath around axons, dramatically boosts action potential conduction velocity. In addition to this canonical function of oligodendrocytes, it is now known that oligodendrocytes can respond to neuronal activity and regulate axonal conduction. Importantly, white matter plasticity, including adaptive responses by oligodendrocytes, has been shown to be involved in learning and memory. In this chapter, the role of oligodendrocytes in axonal conduction and axonal excitability will be reviewed. Focus will be paid to the mechanisms through which oligodendrocytes, including perineuronal oligodendrocytes, facilitate and suppress axonal conduction.
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Affiliation(s)
- Yoshihiko Yamazaki
- Department of Physiology, Yamagata University School of Medicine, Yamagata, Japan.
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23
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Studying and modulating schizophrenia-associated dysfunctions of oligodendrocytes with patient-specific cell systems. NPJ SCHIZOPHRENIA 2018; 4:23. [PMID: 30451850 PMCID: PMC6242875 DOI: 10.1038/s41537-018-0066-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 10/30/2018] [Indexed: 02/07/2023]
Abstract
Postmortem studies in patients with schizophrenia (SCZ) have revealed deficits in myelination, abnormalities in myelin gene expression and altered numbers of oligodendrocytes in the brain. However, gaining mechanistic insight into oligodendrocyte (OL) dysfunction and its contribution to SCZ has been challenging because of technical hurdles. The advent of individual patient-derived human-induced pluripotent stem cells (hiPSCs), combined with the generation of in principle any neuronal and glial cell type, including OLs and oligodendrocyte precursor cells (OPCs), holds great potential for understanding the molecular basis of the aetiopathogenesis of genetically complex psychiatric diseases such as SCZ and could pave the way towards personalized medicine. The development of neuronal and glial co-culture systems now appears to enable the in vitro study of SCZ-relevant neurobiological endophenotypes, including OL dysfunction and myelination, with unprecedented construct validity. Nonetheless, the meaningful stratification of patients before the subsequent functional analyses of patient-derived cell systems still represents an important bottleneck. Here, to improve the predictive power of ex vivo disease modelling we propose using hiPSC technology to focus on representatives of patient subgroups stratified for genomic and/or phenomic features and neurobiological cell systems. Therefore, this review will outline the evidence for the involvement of OPCs/OLs in SCZ in the context of their proposed functions, including myelination and axon support, the implications for hiPSC-based cellular disease modelling and potential strategies for patient selection.
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24
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Hagiwara A, Hori M, Kamagata K, Warntjes M, Matsuyoshi D, Nakazawa M, Ueda R, Andica C, Koshino S, Maekawa T, Irie R, Takamura T, Kumamaru KK, Abe O, Aoki S. Myelin Measurement: Comparison Between Simultaneous Tissue Relaxometry, Magnetization Transfer Saturation Index, and T 1w/T 2w Ratio Methods. Sci Rep 2018; 8:10554. [PMID: 30002497 PMCID: PMC6043493 DOI: 10.1038/s41598-018-28852-6] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 07/02/2018] [Indexed: 01/06/2023] Open
Abstract
Magnetization transfer (MT) imaging has been widely used for estimating myelin content in the brain. Recently, two other approaches, namely simultaneous tissue relaxometry of R1 and R2 relaxation rates and proton density (SyMRI) and the ratio of T1-weighted to T2-weighted images (T1w/T2w ratio), were also proposed as methods for measuring myelin. SyMRI and MT imaging have been reported to correlate well with actual myelin by histology. However, for T1w/T2w ratio, such evidence is limited. In 20 healthy adults, we examined the correlation between these three methods, using MT saturation index (MTsat) for MT imaging. After calibration, white matter (WM) to gray matter (GM) contrast was the highest for SyMRI among these three metrics. Even though SyMRI and MTsat showed strong correlation in the WM (r = 0.72), only weak correlation was found between T1w/T2w and SyMRI (r = 0.45) or MTsat (r = 0.38) (correlation coefficients significantly different from each other, with p values < 0.001). In subcortical and cortical GM, these measurements showed moderate to strong correlations to each other (r = 0.54 to 0.78). In conclusion, the high correlation between SyMRI and MTsat indicates that both methods are similarly suited to measure myelin in the WM, whereas T1w/T2w ratio may be less optimal.
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Affiliation(s)
- Akifumi Hagiwara
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan.
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
| | - Masaaki Hori
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan
| | - Koji Kamagata
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan
| | - Marcel Warntjes
- SyntheticMR AB, Linköping, Sweden
- Center for Medical Imaging Science and Visualization (CMIV), Linköping, Sweden
| | - Daisuke Matsuyoshi
- Araya Inc., Tokyo, Japan
- Research Institute for Science and Engineering, Waseda University, Waseda, Japan
- Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Misaki Nakazawa
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan
| | - Ryo Ueda
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo, Japan
- Office of Radiation Technology, Keio University Hospital, Tokyo, Japan
| | - Christina Andica
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan
| | - Saori Koshino
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Tomoko Maekawa
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Ryusuke Irie
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Tomohiro Takamura
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan
| | | | - Osamu Abe
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Shigeki Aoki
- Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan
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25
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Janowska J, Sypecka J. Therapeutic Strategies for Leukodystrophic Disorders Resulting from Perinatal Asphyxia: Focus on Myelinating Oligodendrocytes. Mol Neurobiol 2018; 55:4388-4402. [PMID: 28660484 PMCID: PMC5884907 DOI: 10.1007/s12035-017-0647-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 06/07/2017] [Indexed: 12/12/2022]
Abstract
Perinatal asphyxia results from the action of different risk factors like complications during pregnancy, preterm delivery, or long and difficult labor. Nowadays, it is still the leading cause of neonatal brain injury known as hypoxic-ischemic encephalopathy (HIE) and resulting neurological disorders. A temporal limitation of oxygen, glucose, and trophic factors supply results in alteration of neural cell differentiation and functioning and/or leads to their death. Among the affected cells are oligodendrocytes, responsible for myelinating the central nervous system (CNS) and formation of white matter. Therefore, one of the major consequences of the experienced HIE is leukodystrophic diseases resulting from oligodendrocyte deficiency or malfunctioning. The therapeutic strategies applied after perinatal asphyxia are aimed at reducing brain damage and promoting the endogenous neuroreparative mechanisms. In this review, we focus on the biology of oligodendrocytes and discuss present clinical treatments in the context of their efficiency in preserving white matter structure and preventing cognitive and behavioral deficits after perinatal asphyxia.
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Affiliation(s)
- Justyna Janowska
- NeuroRepair Department, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego str., 02-106, Warsaw, Poland
| | - Joanna Sypecka
- NeuroRepair Department, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego str., 02-106, Warsaw, Poland.
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26
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Serdar M, Herz J, Kempe K, Winterhager E, Jastrow H, Heumann R, Felderhoff-Müser U, Bendix I. Protection of Oligodendrocytes Through Neuronal Overexpression of the Small GTPase Ras in Hyperoxia-Induced Neonatal Brain Injury. Front Neurol 2018; 9:175. [PMID: 29619004 PMCID: PMC5871665 DOI: 10.3389/fneur.2018.00175] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 03/06/2018] [Indexed: 12/29/2022] Open
Abstract
Prematurely born infants are highly susceptible to various environmental factors, such as inflammation, drug exposure, and also high environmental oxygen concentrations. Hyperoxia induces perinatal brain injury affecting white and gray matter development. It is well known that mitogen-activated protein kinase signaling is involved in cell survival, proliferation, and differentiation. Therefore, we aim to elucidate cell-specific responses of neuronal overexpression of the small GTPase Ras on hyperoxia-mediated brain injury. Six-day-old (P6) synRas mice (neuronal Ras overexpression under the synapsin promoter) or wild-type littermates were kept under hyperoxia (80% oxygen) or room air (21% oxygen) for 24 h. Apoptosis was analyzed by Western blot of cleaved Caspase-3 and neuronal and oligodendrocyte degeneration via immunohistochemistry. Short-term differentiation capacity of oligodendrocytes was assessed by quantification of myelin basic protein expression at P11. Long-lasting changes of hyperoxia-induced alteration of myelin structures were evaluated via transmission electron microscopy in young adult animals (P42). Western blot analysis of active Caspase-3 demonstrates a significant upregulation in wild-type littermates exposed to hyperoxia whereas synRas mice did not show any marked alteration of cleaved Caspase-3 protein levels. Immunohistochemistry revealed a protective effect of neuronal Ras overexpression on neuron and oligodendrocyte survival. Hyperoxia-induced hypomyelination in wild-type littermates was restored in synRas mice. These short-term protective effects through promotion of neuronal survival translated into long-lasting improvement of ultrastructural alterations of myelin sheaths in mice with neuronal overexpression of Ras compared with hyperoxic wild-type mice. Our data suggest that transgenic increase of neuronal Ras activity in the immature brain results in secondary protection of oligodendrocytes from hyperoxia-induced white matter brain injury.
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Affiliation(s)
- Meray Serdar
- Department of Pediatrics I, Neonatology, University Hospital, University Duisburg-Essen, Essen, Germany
| | - Josephine Herz
- Department of Pediatrics I, Neonatology, University Hospital, University Duisburg-Essen, Essen, Germany
| | - Karina Kempe
- Department of Pediatrics I, Neonatology, University Hospital, University Duisburg-Essen, Essen, Germany
| | - Elke Winterhager
- Imaging Center Essen, EM Unit, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Holger Jastrow
- Imaging Center Essen, EM Unit, University Hospital Essen, University Duisburg-Essen, Essen, Germany.,Institute of Anatomy, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Rolf Heumann
- Biochemistry II, Molecular Neurobiochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Ursula Felderhoff-Müser
- Department of Pediatrics I, Neonatology, University Hospital, University Duisburg-Essen, Essen, Germany
| | - Ivo Bendix
- Department of Pediatrics I, Neonatology, University Hospital, University Duisburg-Essen, Essen, Germany
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27
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Osso LA, Chan JR. Architecting the myelin landscape. Curr Opin Neurobiol 2017; 47:1-7. [PMID: 28709021 PMCID: PMC5732869 DOI: 10.1016/j.conb.2017.06.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Revised: 06/03/2017] [Accepted: 06/26/2017] [Indexed: 02/03/2023]
Abstract
Myelin increases the speed and efficiency of action potential propagation. Yet, not all axons are myelinated and some axons are discontinuously myelinated, prompting the question of how myelinating glia select axons for myelination. Whereas myelination by Schwann cells depends on axonal induction, oligodendrocytes can form myelin membrane in the absence of axons. However, oligodendrocytes alone cannot architect the complex myelination patterns of the central nervous system and recent advances have implicated axonal signaling in this process. This review considers how oligodendrocytes and their precursors could be influenced by inductive, attractive, permissive, repulsive, and preventative cues, and discusses recent evidence identifying synaptic activity and membrane-bound adhesion molecules as such cues directing axon selection.
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Affiliation(s)
- Lindsay A Osso
- UCSF Weill Neuroscience Graduate Program and Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Jonah R Chan
- UCSF Weill Neuroscience Graduate Program and Department of Neurology, University of California, San Francisco, San Francisco, CA, USA.
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28
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Dimou L, Simons M. Diversity of oligodendrocytes and their progenitors. Curr Opin Neurobiol 2017; 47:73-79. [PMID: 29078110 DOI: 10.1016/j.conb.2017.09.015] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 08/18/2017] [Accepted: 09/21/2017] [Indexed: 01/01/2023]
Abstract
The established function of oligodendrocytes and their progenitors is to drive the cellular events of myelination, a highly diversified process necessary to match the needs of various neuronal subtypes and networks. The morphological and molecular heterogeneity of oligodendrocytes and their progenitors point to functions beyond establishing saltatory nerve conduction. Here, we review the diversity in the oligodendroglial lineage as well as the classical and new functions identified for oligodendrocytes and their progenitors. Because oligodendroglia remain highly responsive to environmental changes, they likely contribute to various neurological and psychiatric diseases.
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Affiliation(s)
- Leda Dimou
- Molecular and Translational Neuroscience, Department of Neurology, Ulm University, 89081 Ulm, Germany; Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany.
| | - Mikael Simons
- Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany; Institute of Neuronal Cell Biology, Technical University Munich, 80805 Munich, Germany; German Center for Neurodegenerative Disease (DZNE), 81377 Munich, Germany; Max Planck Institute of Experimental Medicine, Cellular Neuroscience, 37075 Göttingen, Germany.
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29
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Birey F, Kokkosis AG, Aguirre A. Oligodendroglia-lineage cells in brain plasticity, homeostasis and psychiatric disorders. Curr Opin Neurobiol 2017; 47:93-103. [PMID: 29073529 DOI: 10.1016/j.conb.2017.09.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 09/20/2017] [Accepted: 09/25/2017] [Indexed: 12/11/2022]
Abstract
Adult oligodendrocyte progenitor cells are uniformly distributed in both gray and white matter, displaying robust proliferative and migratory potential during health and disease. Recently, developments in new experimental approaches have brought about several novel insights about NG2-glia and myelinating oligodendrocytes, indicating a diverse toolkit of functions in experience-dependent myelination and homeostasis in the adult CNS. In this review, we summarize some of the topical studies that highlight newly emerging findings implicating oligodendroglia-lineage cells in brain plasticity, homeostasis and pathophysiology of neuropsychiatric disorders.
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Affiliation(s)
- F Birey
- Stanford University, Department of Psychiatry and Behavioral Sciences, United States
| | - A G Kokkosis
- SUNY, Stony Brook, Department of Pharmacological Sciences, United States
| | - A Aguirre
- SUNY, Stony Brook, Department of Pharmacological Sciences, United States.
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30
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Gibson EM, Geraghty AC, Monje M. Bad wrap: Myelin and myelin plasticity in health and disease. Dev Neurobiol 2017; 78:123-135. [PMID: 28986960 DOI: 10.1002/dneu.22541] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 08/31/2017] [Accepted: 10/03/2017] [Indexed: 12/21/2022]
Abstract
Human central nervous system myelin development extends well into the fourth decade of life, and this protracted period underscores the potential for experience to modulate myelination. The concept of myelin plasticity implies adaptability in myelin structure and function in response to experiences during development and beyond. Mounting evidence supports this concept of neuronal activity-regulated changes in myelin-forming cells, including oligodendrocyte precursor cell proliferation, oligodendrogenesis and modulation of myelin microstructure. In healthy individuals, myelin plasticity in associative white matter structures of the brain is implicated in learning and motor function in both rodents and humans. Activity-dependent changes in myelin-forming cells may influence the function of neural networks that depend on the convergence of numerous neural signals on both a temporal and spatial scale. However, dysregulation of myelin plasticity can disadvantageously alter myelin microstructure and result in aberrant circuit function or contribute to pathological cell proliferation. Emerging roles for myelin plasticity in normal neurological function and in disease are discussed. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 123-135, 2018.
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Affiliation(s)
- Erin M Gibson
- Department of Neurology, Stanford University School of Medicine, Stanford, California, 94305
| | - Anna C Geraghty
- Department of Neurology, Stanford University School of Medicine, Stanford, California, 94305
| | - Michelle Monje
- Department of Neurology, Stanford University School of Medicine, Stanford, California, 94305
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31
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Kaller MS, Lazari A, Blanco-Duque C, Sampaio-Baptista C, Johansen-Berg H. Myelin plasticity and behaviour-connecting the dots. Curr Opin Neurobiol 2017; 47:86-92. [PMID: 29054040 PMCID: PMC5844949 DOI: 10.1016/j.conb.2017.09.014] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 08/29/2017] [Accepted: 09/21/2017] [Indexed: 12/31/2022]
Abstract
Changes in white matter and myelin are associated with learning during adulthood across species. The causal link between myelin plasticity and behaviour remains elusive. Preventing the differentiation of new OLs can impair learning within the first few hours. Myelin remodelling may occur through many different routes and mechanism. The functional arrangement of myelination along axons can be complex and diverse.
Myelin sheaths in the vertebrate nervous system enable faster impulse propagation, while myelinating glia provide vital support to axons. Once considered a static insulator, converging evidence now suggests that myelin in the central nervous system can be dynamically regulated by neuronal activity and continues to participate in nervous system plasticity beyond development. While the link between experience and myelination gains increased recognition, it is still unclear what role such adaptive myelination plays in facilitating and shaping behaviour. Additionally, fundamental mechanisms and principles underlying myelin remodelling remain poorly understood. In this review, we will discuss new insights into the link between myelin plasticity and behaviour, as well as mechanistic aspects of myelin remodelling that may help to elucidate this intriguing process.
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Affiliation(s)
- Malte Sebastian Kaller
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford OX1 2JD, United Kingdom.
| | - Alberto Lazari
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford OX1 2JD, United Kingdom
| | - Cristina Blanco-Duque
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford OX1 2JD, United Kingdom
| | - Cassandra Sampaio-Baptista
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford OX1 2JD, United Kingdom
| | - Heidi Johansen-Berg
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford OX1 2JD, United Kingdom
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32
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Subcellular electrical stimulation of neurons enhances the myelination of axons by oligodendrocytes. PLoS One 2017; 12:e0179642. [PMID: 28671962 PMCID: PMC5495216 DOI: 10.1371/journal.pone.0179642] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 06/01/2017] [Indexed: 11/30/2022] Open
Abstract
Myelin formation has been identified as a modulator of neural plasticity. New tools are required to investigate the mechanisms by which environmental inputs and neural activity regulate myelination patterns. In this study, we demonstrate a microfluidic compartmentalized culture system with integrated electrical stimulation capabilities that can induce neural activity by whole cell and focal stimulation. A set of electric field simulations was performed to confirm spatial restriction of the electrical input in the compartmentalized culture system. We further demonstrate that electrode localization is a key consideration for generating uniform the stimulation of neuron and oligodendrocytes within the compartments. Using three configurations of the electrodes we tested the effects of subcellular activation of neural activity on distal axon myelination with oligodendrocytes. We further investigated if oligodendrocytes have to be exposed to the electrical field to induce axon myelination. An isolated stimulation of cell bodies and proximal axons had the same effect as an isolated stimulation of distal axons co-cultured with oligodendrocytes, and the two modes had a non-different result than whole cell stimulation. Our platform enabled the demonstration that electrical stimulation enhances oligodendrocyte maturation and myelin formation independent of the input localization and oligodendrocyte exposure to the electrical field.
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33
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Yamazaki Y, Hozumi Y, Kaneko K, Fujii S. Modulatory Effects of Perineuronal Oligodendrocytes on Neuronal Activity in the Rat Hippocampus. Neurochem Res 2017; 43:27-40. [PMID: 28444636 DOI: 10.1007/s11064-017-2278-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 04/17/2017] [Accepted: 04/20/2017] [Indexed: 12/31/2022]
Abstract
Action potentials are fundamental to relaying information from region to region in the nervous system. Changes in action potential firing patterns in neural circuits influence how the brain processes information. In our previous study, we focused on interneuron/perineuronal astrocyte pairs in the hippocampal CA1 region and reported that direct depolarization of perineuronal astrocytes modulated the firing pattern of interneurons. In the current study, we investigated the morphological and electrophysiological properties of perineuronal oligodendrocytes, and examined their modulatory effects on interneuronal firing in the CA1 region. Perineuronal oligodendrocytes only had a few processes, which were crooked, intricately twisted, and twined around the soma and proximal region of the main processes of adjacent interneurons. Whole-cell current patterns of perineuronal oligodendrocytes were homogenous and the current-voltage relationship showed remarkable outward rectification. Although the K+ channel blockers, tetraethylammonium and 4-aminopyridine, clearly blocked outward currents, Ba2+ did not significantly alter whole-cell currents. Unlike perineuronal astrocytes, the depolarization of perineuronal oligodendrocytes had no effect on interneuronal firing; however, when the interneurons were firing at a higher frequency, the hyperpolarization of perineuronal oligodendrocytes suppressed their action potentials. The suppressive effects of perineuronal oligodendrocytes were inhibited in the presence of a low concentration of tetraethylammonium, which selectively blocked deep and fast afterhyperpolarization. These results suggest that perineuronal oligodendrocytes suppress interneuronal firing through their influence on K+ channels, which are responsible for deep and fast afterhyperpolarization.
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Affiliation(s)
- Yoshihiko Yamazaki
- Department of Physiology, Yamagata University School of Medicine, 2-2-2 Iida-Nishi, Yamagata, 990-9585, Japan.
| | - Yasukazu Hozumi
- Department of Anatomy & Cell Biology, Yamagata University School of Medicine, Yamagata, 990-9585, Japan.,Department of Cell Biology and Morphology, Akita University Graduate School of Medicine, Akita, 010-8543, Japan
| | - Kenya Kaneko
- Department of Physiology, Yamagata University School of Medicine, 2-2-2 Iida-Nishi, Yamagata, 990-9585, Japan
| | - Satoshi Fujii
- Department of Physiology, Yamagata University School of Medicine, 2-2-2 Iida-Nishi, Yamagata, 990-9585, Japan
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34
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Drommelschmidt K, Serdar M, Bendix I, Herz J, Bertling F, Prager S, Keller M, Ludwig AK, Duhan V, Radtke S, de Miroschedji K, Horn PA, van de Looij Y, Giebel B, Felderhoff-Müser U. Mesenchymal stem cell-derived extracellular vesicles ameliorate inflammation-induced preterm brain injury. Brain Behav Immun 2017; 60:220-232. [PMID: 27847282 DOI: 10.1016/j.bbi.2016.11.011] [Citation(s) in RCA: 203] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 11/04/2016] [Accepted: 11/12/2016] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVE Preterm brain injury is a major cause of disability in later life, and may result in motor, cognitive and behavioural impairment for which no treatment is currently available. The aetiology is considered as multifactorial, and one underlying key player is inflammation leading to white and grey matter injury. Extracellular vesicles secreted by mesenchymal stem/stromal cells (MSC-EVs) have shown therapeutic potential in regenerative medicine. Here, we investigated the effects of MSC-EV treatment on brain microstructure and maturation, inflammatory processes and long-time outcome in a rodent model of inflammation-induced brain injury. METHODS 3-Day-old Wistar rats (P3) were intraperitoneally injected with 0.25mg/kg lipopolysaccharide or saline and treated with two repetitive doses of 1×108 cell equivalents of MSC-EVs per kg bodyweight. Cellular degeneration and reactive gliosis at P5 and myelination at P11 were evaluated by immunohistochemistry and western blot. Long-term cognitive and motor function was assessed by behavioural testing. Diffusion tensor imaging at P125 evaluated long-term microstructural white matter alterations. RESULTS MSC-EV treatment significantly ameliorated inflammation-induced neuronal cellular degeneration reduced microgliosis and prevented reactive astrogliosis. Short-term myelination deficits and long-term microstructural abnormalities of the white matter were restored by MSC-EV administration. Morphological effects of MSC-EV treatment resulted in improved long-lasting cognitive functions INTERPRETATION: MSC-EVs ameliorate inflammation-induced cellular damage in a rat model of preterm brain injury. MSC-EVs may serve as a novel therapeutic option by prevention of neuronal cell death, restoration of white matter microstructure, reduction of gliosis and long-term functional improvement.
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Affiliation(s)
- Karla Drommelschmidt
- Department of Paediatrics I/Neonatology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Meray Serdar
- Department of Paediatrics I/Neonatology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Ivo Bendix
- Department of Paediatrics I/Neonatology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Josephine Herz
- Department of Paediatrics I/Neonatology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Frederik Bertling
- Department of Paediatrics I/Neonatology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Sebastian Prager
- Department of Paediatrics I/Neonatology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Matthias Keller
- Department of Paediatrics I/Neonatology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Anna-Kristin Ludwig
- Institute of Transfusion Medicine, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Vikas Duhan
- Institute of Immunology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Stefan Radtke
- Institute of Transfusion Medicine, University Hospital Essen, University of Duisburg-Essen, Essen, Germany; Clinical Research Division, Fred Hutchinson Cancer Research Centre, Seattle, WA 98109, USA
| | - Kyra de Miroschedji
- Institute of Transfusion Medicine, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Peter A Horn
- Institute of Transfusion Medicine, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Yohan van de Looij
- Division of Child Growth and Development, Department of Paediatrics, University of Geneva, Geneva, Switzerland; Laboratory of Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Bernd Giebel
- Institute of Transfusion Medicine, University Hospital Essen, University of Duisburg-Essen, Essen, Germany.
| | - Ursula Felderhoff-Müser
- Department of Paediatrics I/Neonatology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany.
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35
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Arshad M, Stanley JA, Raz N. Test-retest reliability and concurrent validity of in vivo myelin content indices: Myelin water fraction and calibrated T 1 w/T 2 w image ratio. Hum Brain Mapp 2016; 38:1780-1790. [PMID: 28009069 DOI: 10.1002/hbm.23481] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 11/06/2016] [Accepted: 11/21/2016] [Indexed: 11/09/2022] Open
Abstract
In an age-heterogeneous sample of healthy adults, we examined test-retest reliability (with and without participant repositioning) of two popular MRI methods of estimating myelin content: modeling the short spin-spin (T2 ) relaxation component of multi-echo imaging data and computing the ratio of T1 -weighted and T2 -weighted images (T1 w/T2 w). Taking the myelin water fraction (MWF) index of myelin content derived from the multi-component T2 relaxation data as a standard, we evaluate the concurrent and differential validity of T1 w/T2 w ratio images. The results revealed high reliability of MWF and T1 w/T2 w ratio. However, we found significant correlations of low to moderate magnitude between MWF and the T1 w/T2 w ratio in only two of six examined regions of the cerebral white matter. Notably, significant correlations of the same or greater magnitude were observed for T1 w/T2 w ratio and the intermediate T2 relaxation time constant, which is believed to reflect differences in the mobility of water between the intracellular and extracellular compartments. We conclude that although both methods are highly reliable and thus well-suited for longitudinal studies, T1 w/T2 w ratio has low criterion validity and may be not an optimal index of subcortical myelin content. Hum Brain Mapp 38:1780-1790, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Muzamil Arshad
- Department of Psychiatry and Behavioral Neuroscience, School of Medicine, Wayne State University, Detroit, Michigan.,Institute of Gerontology, Wayne State University, Detroit, Michigan
| | - Jeffrey A Stanley
- Department of Psychiatry and Behavioral Neuroscience, School of Medicine, Wayne State University, Detroit, Michigan
| | - Naftali Raz
- Institute of Gerontology, Wayne State University, Detroit, Michigan.,Department of Psychology, Wayne State University, Detroit, Michigan
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36
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Purger D, Gibson EM, Monje M. Myelin plasticity in the central nervous system. Neuropharmacology 2016; 110:563-573. [DOI: 10.1016/j.neuropharm.2015.08.001] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Revised: 07/20/2015] [Accepted: 08/01/2015] [Indexed: 12/31/2022]
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37
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Micheva KD, Wolman D, Mensh BD, Pax E, Buchanan J, Smith SJ, Bock DD. A large fraction of neocortical myelin ensheathes axons of local inhibitory neurons. eLife 2016; 5. [PMID: 27383052 PMCID: PMC4972537 DOI: 10.7554/elife.15784] [Citation(s) in RCA: 167] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 07/05/2016] [Indexed: 12/30/2022] Open
Abstract
Myelin is best known for its role in increasing the conduction velocity and metabolic efficiency of long-range excitatory axons. Accordingly, the myelin observed in neocortical gray matter is thought to mostly ensheath excitatory axons connecting to subcortical regions and distant cortical areas. Using independent analyses of light and electron microscopy data from mouse neocortex, we show that a surprisingly large fraction of cortical myelin (half the myelin in layer 2/3 and a quarter in layer 4) ensheathes axons of inhibitory neurons, specifically of parvalbumin-positive basket cells. This myelin differs significantly from that of excitatory axons in distribution and protein composition. Myelin on inhibitory axons is unlikely to meaningfully hasten the arrival of spikes at their pre-synaptic terminals, due to the patchy distribution and short path-lengths observed. Our results thus highlight the need for exploring alternative roles for myelin in neocortical circuits.
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Affiliation(s)
- Kristina D Micheva
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, United States
| | - Dylan Wolman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Brett D Mensh
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Elizabeth Pax
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - JoAnn Buchanan
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, United States
| | - Stephen J Smith
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, United States
| | - Davi D Bock
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
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38
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Chang KJ, Redmond SA, Chan JR. Remodeling myelination: implications for mechanisms of neural plasticity. Nat Neurosci 2016; 19:190-7. [PMID: 26814588 DOI: 10.1038/nn.4200] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Accepted: 10/12/2015] [Indexed: 02/08/2023]
Abstract
One of the most significant paradigm shifts in membrane remodeling is the emerging view that membrane transformation is not exclusively controlled by cytoskeletal rearrangement, but also by biophysical constraints, adhesive forces, membrane curvature and compaction. One of the most exquisite examples of membrane remodeling is myelination. The advent of myelin was instrumental in advancing the nervous system during vertebrate evolution. With more rapid and efficient communication between neurons, faster and more complex computations could be performed in a given time and space. Our knowledge of how myelin-forming oligodendrocytes select and wrap axons has been limited by insufficient spatial and temporal resolution. By virtue of recent technological advances, progress has clarified longstanding controversies in the field. Here we review insights into myelination, from target selection to axon wrapping and membrane compaction, and discuss how understanding these processes has unexpectedly opened new avenues of insight into myelination-centered mechanisms of neural plasticity.
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Affiliation(s)
- Kae-Jiun Chang
- Department of Neurology, University of California, San Francisco, California, USA
| | - Stephanie A Redmond
- Department of Neurology, University of California, San Francisco, California, USA.,Program in Neuroscience, University of California, San Francisco, California, USA
| | - Jonah R Chan
- Department of Neurology, University of California, San Francisco, California, USA.,Program in Neuroscience, University of California, San Francisco, California, USA
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Seidl AH, Rubel EW. Systematic and differential myelination of axon collaterals in the mammalian auditory brainstem. Glia 2016; 64:487-94. [PMID: 26556176 PMCID: PMC4752408 DOI: 10.1002/glia.22941] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 10/20/2015] [Indexed: 12/19/2022]
Abstract
A brainstem circuit for encoding the spatial location of sounds involves neurons in the cochlear nucleus that project to medial superior olivary (MSO) neurons on both sides of the brain via a single bifurcating axon. Neurons in MSO act as coincidence detectors, responding optimally when signals from the two ears arrive within a few microseconds. To achieve this, transmission of signals along the contralateral collateral must be faster than transmission of the same signals along the ipsilateral collateral. We demonstrate that this is achieved by differential regulation of myelination and axon caliber along the ipsilateral and contralateral branches of single axons; ipsilateral axon branches have shorter internode lengths and smaller caliber than contralateral branches. The myelination difference is established prior to the onset of hearing. We conclude that this differential myelination and axon caliber requires local interactions between axon collaterals and surrounding oligodendrocytes on the two sides of the brainstem.
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Affiliation(s)
- Armin H. Seidl
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, WA
- Department of Neurology, University of Washington, Seattle, WA
| | - Edwin W Rubel
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, WA
- Department of Otolaryngology – Head & Neck Surgery, University of Washington, Seattle, WA
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Serdar M, Herz J, Kempe K, Lumpe K, Reinboth BS, Sizonenko SV, Hou X, Herrmann R, Hadamitzky M, Heumann R, Hansen W, Sifringer M, van de Looij Y, Felderhoff-Müser U, Bendix I. Fingolimod protects against neonatal white matter damage and long-term cognitive deficits caused by hyperoxia. Brain Behav Immun 2016; 52:106-119. [PMID: 26456693 DOI: 10.1016/j.bbi.2015.10.004] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Revised: 09/26/2015] [Accepted: 10/03/2015] [Indexed: 11/29/2022] Open
Abstract
Cerebral white matter injury is a leading cause of adverse neurodevelopmental outcome in prematurely born infants involving cognitive deficits in later life. Despite increasing knowledge about the pathophysiology of perinatal brain injury, therapeutic options are limited. In the adult demyelinating disease multiple sclerosis the sphingosine-1-phosphate (S1P) receptor modulating substance fingolimod (FTY720) has beneficial effects. Herein, we evaluated the neuroprotective potential of FTY720 in a neonatal model of oxygen-toxicity, which is associated with hypomyelination and impaired neuro-cognitive outcome. A single dose of FTY720 (1mg/kg) at the onset of neonatal hyperoxia (24h 80% oxygen on postnatal day 6) resulted in improvement of neuro-cognitive development persisting into adulthood. This was associated with reduced microstructural white matter abnormalities 4 months after the insult. In search of the underlying mechanisms potential non-classical (i.e. lymphocyte-independent) pathways were analysed shortly after the insult, comprising modulation of oxidative stress and local inflammatory responses as well as myelination, oligodendrocyte degeneration and maturation. Treatment with FTY720 reduced hyperoxia-induced oxidative stress, microglia activation and associated pro-inflammatory cytokine expression. In vivo and in vitro analyses further revealed that oxygen-induced hypomyelination is restored to control levels, which was accompanied by reduced oligodendrocyte degeneration and enhanced maturation. Furthermore, hyperoxia-induced elevation of S1P receptor 1 (S1P1) protein expression on in vitro cultured oligodendrocyte precursor cells was reduced by activated FTY720 and protection from degeneration is abrogated after selective S1P1 blockade. Finally, FTY720s' classical mode of action (i.e. retention of immune cells within peripheral lymphoid organs) was analysed demonstrating that FTY720 diminished circulating lymphocyte counts independent from hyperoxia. Cerebral immune cell counts remained unchanged by hyperoxia and by FTY720 treatment. Taken together, these results suggest that beneficial effects of FTY720 in neonatal oxygen-induced brain injury may be rather attributed to its anti-oxidative and anti-inflammatory capacity acting in concert with a direct protection of developing oligodendrocytes than to a modulation of peripheral lymphocyte trafficking. Thus, FTY720 might be a potential new therapeutic option for the treatment of neonatal brain injury through reduction of white matter damage.
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Affiliation(s)
- Meray Serdar
- Department of Pediatrics 1 - Neonatology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Josephine Herz
- Department of Pediatrics 1 - Neonatology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Karina Kempe
- Department of Pediatrics 1 - Neonatology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Katharina Lumpe
- Department of Pediatrics 1 - Neonatology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Barbara S Reinboth
- Department of Pediatrics 1 - Neonatology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | | | - Xinlin Hou
- Department of Pediatrics 1 - Neonatology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Ralf Herrmann
- Department of Pediatrics 1 - Neonatology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Martin Hadamitzky
- Institute of Medical Psychology and Behavioral Immunobiology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Rolf Heumann
- Molecular Neurochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Wiebke Hansen
- Institute of Medical Microbiology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Marco Sifringer
- Department of Anesthesiology and Intensive Care Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Yohan van de Looij
- Department of Pediatrics, University of Geneva, Genève, Switzerland; Laboratory of Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Ursula Felderhoff-Müser
- Department of Pediatrics 1 - Neonatology, University Hospital Essen, University Duisburg-Essen, Essen, Germany.
| | - Ivo Bendix
- Department of Pediatrics 1 - Neonatology, University Hospital Essen, University Duisburg-Essen, Essen, Germany.
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41
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Pearson-Leary J, Osborne DM, McNay EC. Role of Glia in Stress-Induced Enhancement and Impairment of Memory. Front Integr Neurosci 2016; 9:63. [PMID: 26793072 PMCID: PMC4707238 DOI: 10.3389/fnint.2015.00063] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 12/05/2015] [Indexed: 12/20/2022] Open
Abstract
Both acute and chronic stress profoundly affect hippocampally-dependent learning and memory: moderate stress generally enhances, while chronic or extreme stress can impair, neural and cognitive processes. Within the brain, stress elevates both norepinephrine and glucocorticoids, and both affect several genomic and signaling cascades responsible for modulating memory strength. Memories formed at times of stress can be extremely strong, yet stress can also impair memory to the point of amnesia. Often overlooked in consideration of the impact of stress on cognitive processes, and specifically memory, is the important contribution of glia as a target for stress-induced changes. Astrocytes, microglia, and oligodendrocytes all have unique contributions to learning and memory. Furthermore, these three types of glia express receptors for both norepinephrine and glucocorticoids and are hence immediate targets of stress hormone actions. It is becoming increasingly clear that inflammatory cytokines and immunomodulatory molecules released by glia during stress may promote many of the behavioral effects of acute and chronic stress. In this review, the role of traditional genomic and rapid hormonal mechanisms working in concert with glia to affect stress-induced learning and memory will be emphasized.
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Affiliation(s)
- Jiah Pearson-Leary
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia Philadelphia, PA, USA
| | | | - Ewan C McNay
- Behavioral Neuroscience and Biology, University at Albany Albany, NY, USA
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von Bernhardi R, Eugenín-von Bernhardi J, Flores B, Eugenín León J. Glial Cells and Integrity of the Nervous System. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 949:1-24. [PMID: 27714682 DOI: 10.1007/978-3-319-40764-7_1] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Today, there is enormous progress in understanding the function of glial cells, including astroglia, oligodendroglia, Schwann cells, and microglia. Around 150 years ago, glia were viewed as a glue among neurons. During the course of the twentieth century, microglia were discovered and neuroscientists' views evolved toward considering glia only as auxiliary cells of neurons. However, over the last two to three decades, glial cells' importance has been reconsidered because of the evidence on their involvement in defining central nervous system architecture, brain metabolism, the survival of neurons, development and modulation of synaptic transmission, propagation of nerve impulses, and many other physiological functions. Furthermore, increasing evidence shows that glia are involved in the mechanisms of a broad spectrum of pathologies of the nervous system, including some psychiatric diseases, epilepsy, and neurodegenerative diseases to mention a few. It appears safe to say that no neurological disease can be understood without considering neuron-glia crosstalk. Thus, this book aims to show different roles played by glia in the healthy and diseased nervous system, highlighting some of their properties while considering that the various glial cell types are essential components not only for cell function and integration among neurons, but also for the emergence of important brain homeostasis.
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Affiliation(s)
- Rommy von Bernhardi
- Department of Neurology, School of Medicine, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile.
| | - Jaime Eugenín-von Bernhardi
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians-University, Pettenkoferstr.12, 80336, Munich, Germany.,Graduate School of Systemic Neuroscience, Ludwig-Maximilians-University, 82152, Planegg-Martinsried, Munich, Germany
| | - Betsi Flores
- Department of Neurology, School of Medicine, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Jaime Eugenín León
- Department of Biology, Faculty of Chemistry and Biology, USACH, Santiago, Chile
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Elsayed M, Magistretti PJ. A New Outlook on Mental Illnesses: Glial Involvement Beyond the Glue. Front Cell Neurosci 2015; 9:468. [PMID: 26733803 PMCID: PMC4679853 DOI: 10.3389/fncel.2015.00468] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 11/16/2015] [Indexed: 12/27/2022] Open
Abstract
Mental illnesses have long been perceived as the exclusive consequence of abnormalities in neuronal functioning. Until recently, the role of glial cells in the pathophysiology of mental diseases has largely been overlooked. However recently, multiple lines of evidence suggest more diverse and significant functions of glia with behavior-altering effects. The newly ascribed roles of astrocytes, oligodendrocytes and microglia have led to their examination in brain pathology and mental illnesses. Indeed, abnormalities in glial function, structure and density have been observed in postmortem brain studies of subjects diagnosed with mental illnesses. In this review, we discuss the newly identified functions of glia and highlight the findings of glial abnormalities in psychiatric disorders. We discuss these preclinical and clinical findings implicating the involvement of glial cells in mental illnesses with the perspective that these cells may represent a new target for treatment.
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Affiliation(s)
- Maha Elsayed
- Laboratory of Neuroenergetics and Cellular Dynamics, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne Lausanne, Switzerland
| | - Pierre J Magistretti
- Laboratory of Neuroenergetics and Cellular Dynamics, Brain Mind Institute, Ecole Polytechnique Fédérale de LausanneLausanne, Switzerland; Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and TechnologyThuwal, Saudi Arabia; Department of Psychiatry, Center for Psychiatric Neurosciences, University of LausanneLausanne, Switzerland
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Chen X, Zhang W, Li T, Guo Y, Tian Y, Wang F, Liu S, Shen HY, Feng Y, Xiao L. Impairment of Oligodendroglia Maturation Leads to Aberrantly Increased Cortical Glutamate and Anxiety-Like Behaviors in Juvenile Mice. Front Cell Neurosci 2015; 9:467. [PMID: 26696827 PMCID: PMC4678193 DOI: 10.3389/fncel.2015.00467] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 11/16/2015] [Indexed: 01/19/2023] Open
Abstract
Adolescence is the critical time for developing proper oligodendrocyte (OL)-neuron interaction and the peak of onset for many cognitive diseases, among which anxiety disorders display the highest prevalence. However, whether impairment of de novo OL development causes neuronal abnormalities and contributes to the early onset of anxiety phenotype in childhood still remains unexplored. In this study, we tested the hypothesis that defects in OL maturation manifests cortical neuron function and leads to anxiety-like behaviors in juvenile mice. We report here that conditional knockout of the Olig2 gene (Olig2 cKO) specifically in differentiating OLs in the mouse brain preferentially impaired OL maturation in the gray matter of cerebral cortex. Interestingly, localized proton magnetic resonance spectroscopy revealed that Olig2 cKO mice displayed abnormally elevated cortical glutamate levels. In addition, transmission electron microscopy demonstrated increased vesicle density in excitatory glutamatergic synapses in the cortex of the Olig2 cKO mice. Moreover, juvenile Olig2 cKO mice exhibited anxiety-like behaviors and impairment in behavioral inhibition. Taken together, our results suggest that impaired OL development affects glutamatergic neuron function in the cortex and causes anxiety-related behaviors in juvenile mice. These discoveries raise an intriguing possibility that OL defects may be a contributing mechanism for the onset of anxiety in childhood.
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Affiliation(s)
- Xianjun Chen
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University Chongqing, China
| | - Weiguo Zhang
- Department of Radiology, Institute of Surgery Research, Daping Hospital, Third Military Medical University Chongqing, China
| | - Tao Li
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University Chongqing, China
| | - Yu Guo
- Department of Radiology, Institute of Surgery Research, Daping Hospital, Third Military Medical University Chongqing, China
| | - Yanping Tian
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University Chongqing, China
| | - Fei Wang
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University Chongqing, China
| | - Shubao Liu
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University Chongqing, China
| | - Hai-Ying Shen
- Robert Stone Dow Neurobiology Laboratories, Legacy Research Institute, Portland OR, USA
| | - Yue Feng
- Department of Pharmacology, Emory University School of Medicine, Atlanta GA, USA
| | - Lan Xiao
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University Chongqing, China
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MyelStones: the executive roles of myelin basic protein in myelin assembly and destabilization in multiple sclerosis. Biochem J 2015; 472:17-32. [DOI: 10.1042/bj20150710] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The classic isoforms of myelin basic protein (MBP, 14–21.5 kDa) are essential to formation of the multilamellar myelin sheath of the mammalian central nervous system (CNS). The predominant 18.5-kDa isoform links together the cytosolic surfaces of oligodendrocytes, but additionally participates in cytoskeletal turnover and membrane extension, Fyn-mediated signalling pathways, sequestration of phosphoinositides and maintenance of calcium homoeostasis. All MBP isoforms are intrinsically disordered proteins (IDPs) that interact via molecular recognition fragments (MoRFs), which thereby undergo local disorder-to-order transitions. Their conformations and associations are modulated by environment and by a dynamic barcode of post-translational modifications, particularly phosphorylation by mitogen-activated and other protein kinases and deimination [a hallmark of demyelination in multiple sclerosis (MS)]. The MBPs are thus to myelin what basic histones are to chromatin. Originally thought to be merely structural proteins forming an inert spool, histones are now known to be dynamic entities involved in epigenetic regulation and diseases such as cancer. Analogously, the MBPs are not mere adhesives of compact myelin, but active participants in oligodendrocyte proliferation and in membrane process extension and stabilization during myelinogenesis. A central segment of these proteins is pivotal in membrane-anchoring and SH3 domain (Src homology 3) interaction. We discuss in the present review advances in our understanding of conformational conversions of this classic basic protein upon membrane association, including new thermodynamic analyses of transitions into different structural ensembles and how a shift in the pattern of its post-translational modifications is associated with the pathogenesis and potentially onset of demyelination in MS.
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46
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Mensch S, Baraban M, Almeida R, Czopka T, Ausborn J, El Manira A, Lyons DA. Synaptic vesicle release regulates myelin sheath number of individual oligodendrocytes in vivo. Nat Neurosci 2015; 18:628-30. [PMID: 25849985 PMCID: PMC4427868 DOI: 10.1038/nn.3991] [Citation(s) in RCA: 278] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 02/23/2015] [Indexed: 11/08/2022]
Abstract
The myelination of axons by oligodendrocytes markedly affects CNS function, but how this is regulated by neuronal activity in vivo is not known. We found that blocking synaptic vesicle release impaired CNS myelination by reducing the number of myelin sheaths made by individual oligodendrocytes during their short period of formation. We also found that stimulating neuronal activity increased myelin sheath formation by individual oligodendrocytes. These data indicate that neuronal activity regulates the myelinating capacity of single oligodendrocytes.
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Affiliation(s)
- Sigrid Mensch
- Centre for Neuroregeneration, Centre for Multiple Sclerosis Research, Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
| | - Marion Baraban
- Centre for Neuroregeneration, Centre for Multiple Sclerosis Research, Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
| | - Rafael Almeida
- Centre for Neuroregeneration, Centre for Multiple Sclerosis Research, Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
| | - Tim Czopka
- Centre for Neuroregeneration, Centre for Multiple Sclerosis Research, Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
| | - Jessica Ausborn
- Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
| | | | - David A Lyons
- Centre for Neuroregeneration, Centre for Multiple Sclerosis Research, Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
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Jebelli J, Su W, Hopkins S, Pocock J, Garden GA. Glia: guardians, gluttons, or guides for the maintenance of neuronal connectivity? Ann N Y Acad Sci 2015; 1351:1-10. [PMID: 25752338 DOI: 10.1111/nyas.12711] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 12/29/2014] [Accepted: 01/13/2015] [Indexed: 12/20/2022]
Abstract
An emerging aspect of neuronal-glial interactions is the connection glial cells have to synapses. Mounting research now suggests a far more intimate relationship than previously recognized. Moreover, the current evidence implicating synapse loss in neurodegenerative disease etiology is overwhelming, but the role of glia in the process of synaptic degeneration has only recently been considered in earnest. Each main class of glial cell, including astrocytes, oligodendrocytes, and microglia, performs crucial and multifaceted roles in the maintenance of synaptic function and excitability. As such, aging and/or neuronal stress from disease-related misfolded proteins may involve disruption of multiple non-cell-autonomous synaptic support systems that are mediated by neighboring glia. In addition, glial cell activation induced by injury, ischemia, or neurodegeneration is thought to greatly alter the behavior of glial cells toward neuronal synapses, suggesting that neuroinflammation potentially contributes to synapse loss primarily mediated by altered glial functions. This review discusses recent evidence highlighting novel roles for glial cells at neuronal synapses and in the maintenance of neuronal connectivity, focusing primarily on their implications for neurodegenerative disease research.
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Affiliation(s)
- Joseph Jebelli
- Department of Neurology, University of Washington, Seattle, Washington
| | - Wei Su
- Department of Neurology, University of Washington, Seattle, Washington
| | - Stephanie Hopkins
- Department of Neurology, University of Washington, Seattle, Washington
| | - Jennifer Pocock
- Department of Neuroinflammation, University College London Institute of Neurology, London, United Kingdom
| | - Gwenn A Garden
- Department of Neurology, University of Washington, Seattle, Washington
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