1
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Osso LA, Hughes EG. Dynamics of mature myelin. Nat Neurosci 2024; 27:1449-1461. [PMID: 38773349 DOI: 10.1038/s41593-024-01642-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 04/05/2024] [Indexed: 05/23/2024]
Abstract
Myelin, which is produced by oligodendrocytes, insulates axons to facilitate rapid and efficient action potential propagation in the central nervous system. Traditionally viewed as a stable structure, myelin is now known to undergo dynamic modulation throughout life. This Review examines these dynamics, focusing on two key aspects: (1) the turnover of myelin, involving not only the renewal of constituents but the continuous wholesale replacement of myelin membranes; and (2) the structural remodeling of pre-existing, mature myelin, a newly discovered form of neural plasticity that can be stimulated by external factors, including neuronal activity, behavioral experience and injury. We explore the mechanisms regulating these dynamics and speculate that myelin remodeling could be driven by an asymmetry in myelin turnover or reactivation of pathways involved in myelin formation. Finally, we outline how myelin remodeling could have profound impacts on neural function, serving as an integral component of behavioral adaptation.
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Affiliation(s)
- Lindsay A Osso
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Ethan G Hughes
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA.
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2
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van de Wetering R, Bibi R, Biggerstaff A, Hong S, Pengelly B, Prisinzano TE, La Flamme AC, Kivell BM. Nalfurafine promotes myelination in vitro and facilitates recovery from cuprizone + rapamycin-induced demyelination in mice. Glia 2024. [PMID: 38899723 DOI: 10.1002/glia.24583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 06/05/2024] [Accepted: 06/07/2024] [Indexed: 06/21/2024]
Abstract
The kappa opioid receptor has been identified as a promising therapeutic target for promoting remyelination. In the current study, we evaluated the ability of nalfurafine to promote oligodendrocyte progenitor cell (OPC) differentiation and myelination in vitro, and its efficacy in an extended, cuprizone-induced demyelination model. Primary mouse (C57BL/6J) OPC-containing cultures were treated with nalfurafine (0.6-200 nM), clemastine (0.01-100 μM), T3 (30 ng/mL), or vehicle for 5 days. Using immunocytochemistry and confocal microscopy, we found that nalfurafine treatment increased OPC differentiation, oligodendrocyte (OL) morphological complexity, and myelination of nanofibers in vitro. Adult male mice (C57BL/6J) were given a diet containing 0.2% cuprizone and administered rapamycin (10 mg/kg) once daily for 12 weeks followed by 6 weeks of treatment with nalfurafine (0.01 or 0.1 mg/kg), clemastine (10 mg/kg), or vehicle. We quantified the number of OLs using immunofluorescence, gross myelination using black gold staining, and myelin thickness using electron microscopy. Cuprizone + rapamycin treatment produced extensive demyelination and was accompanied by a loss of mature OLs, which was partially reversed by therapeutic administration of nalfurafine. We also assessed these mice for functional behavioral changes in open-field, horizontal bar, and mouse motor skill sequence tests (complex wheel running). Cuprizone + rapamycin treatment resulted in hyperlocomotion, poorer horizontal bar scores, and less distance traveled on the running wheels. Partial recovery was observed on both the horizontal bar and complex running wheel tests over time, which was facilitated by nalfurafine treatment. Taken together, these data highlight the potential of nalfurafine as a remyelination-promoting therapeutic.
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Affiliation(s)
- Ross van de Wetering
- School of Biological Sciences, Centre for Biodiscovery, Victoria University of Wellington, Wellington, New Zealand
| | - Rabia Bibi
- School of Biological Sciences, Centre for Biodiscovery, Victoria University of Wellington, Wellington, New Zealand
| | - Andy Biggerstaff
- School of Biological Sciences, Centre for Biodiscovery, Victoria University of Wellington, Wellington, New Zealand
| | - Sheein Hong
- School of Biological Sciences, Centre for Biodiscovery, Victoria University of Wellington, Wellington, New Zealand
| | - Bria Pengelly
- School of Biological Sciences, Centre for Biodiscovery, Victoria University of Wellington, Wellington, New Zealand
| | - Thomas E Prisinzano
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Anne C La Flamme
- School of Biological Sciences, Centre for Biodiscovery, Victoria University of Wellington, Wellington, New Zealand
- Malaghan Institute of Medical Research, Wellington, New Zealand
| | - Bronwyn M Kivell
- School of Biological Sciences, Centre for Biodiscovery, Victoria University of Wellington, Wellington, New Zealand
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3
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Prathapan V, Eipert P, Wigger N, Kipp M, Appali R, Schmitt O. Modeling and simulation for prediction of multiple sclerosis progression. Comput Biol Med 2024; 175:108416. [PMID: 38657465 DOI: 10.1016/j.compbiomed.2024.108416] [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: 12/07/2023] [Revised: 03/28/2024] [Accepted: 04/03/2024] [Indexed: 04/26/2024]
Abstract
In light of extensive work that has created a wide range of techniques for predicting the course of multiple sclerosis (MS) disease, this paper attempts to provide an overview of these approaches and put forth an alternative way to predict the disease progression. For this purpose, the existing methods for estimating and predicting the course of the disease have been categorized into clinical, radiological, biological, and computational or artificial intelligence-based markers. Weighing the weaknesses and strengths of these prognostic groups is a profound method that is yet in need and works directly at the level of diseased connectivity. Therefore, we propose using the computational models in combination with established connectomes as a predictive tool for MS disease trajectories. The fundamental conduction-based Hodgkin-Huxley model emerged as promising from examining these studies. The advantage of the Hodgkin-Huxley model is that certain properties of connectomes, such as neuronal connection weights, spatial distances, and adjustments of signal transmission rates, can be taken into account. It is precisely these properties that are particularly altered in MS and that have strong implications for processing, transmission, and interactions of neuronal signaling patterns. The Hodgkin-Huxley (HH) equations as a point-neuron model are used for signal propagation inside a small network. The objective is to change the conduction parameter of the neuron model, replicate the changes in myelin properties in MS and observe the dynamics of the signal propagation across the network. The model is initially validated for different lengths, conduction values, and connection weights through three nodal connections. Later, these individual factors are incorporated into a small network and simulated to mimic the condition of MS. The signal propagation pattern is observed after inducing changes in conduction parameters at certain nodes in the network and compared against a control model pattern obtained before the changes are applied to the network. The signal propagation pattern varies as expected by adapting to the input conditions. Similarly, when the model is applied to a connectome, the pattern changes could give an insight into disease progression. This approach has opened up a new path to explore the progression of the disease in MS. The work is in its preliminary state, but with a future vision to apply this method in a connectome, providing a better clinical tool.
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Affiliation(s)
- Vishnu Prathapan
- Medical School Hamburg University of Applied Sciences and Medical University, Am Kaiserkai 1, 20457, Hamburg, Germany.
| | - Peter Eipert
- Medical School Hamburg University of Applied Sciences and Medical University, Am Kaiserkai 1, 20457, Hamburg, Germany.
| | - Nicole Wigger
- Department of Anatomy, University of Rostock Gertrudenstr 9, 18057, Rostock, Germany.
| | - Markus Kipp
- Department of Anatomy, University of Rostock Gertrudenstr 9, 18057, Rostock, Germany.
| | - Revathi Appali
- Institute of General Electrical Engineering, University of Rostock, Albert-Einstein-Straße 2, 18059, Rostock, Germany; Department of Aging of Individuals and Society, Interdisciplinary Faculty, University of Rostock, Universitätsplatz 1, 18055, Rostock, Germany.
| | - Oliver Schmitt
- Medical School Hamburg University of Applied Sciences and Medical University, Am Kaiserkai 1, 20457, Hamburg, Germany; Department of Anatomy, University of Rostock Gertrudenstr 9, 18057, Rostock, Germany.
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4
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Mercier O, Quilichini PP, Magalon K, Gil F, Ghestem A, Richard F, Boudier T, Cayre M, Durbec P. Transient demyelination causes long-term cognitive impairment, myelin alteration and network synchrony defects. Glia 2024; 72:960-981. [PMID: 38363046 DOI: 10.1002/glia.24513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 01/26/2024] [Accepted: 02/05/2024] [Indexed: 02/17/2024]
Abstract
In the adult brain, activity-dependent myelin plasticity is required for proper learning and memory consolidation. Myelin loss, alteration, or even subtle structural modifications can therefore compromise the network activity, leading to functional impairment. In multiple sclerosis, spontaneous myelin repair process is possible, but it is heterogeneous among patients, sometimes leading to functional recovery, often more visible at the motor level than at the cognitive level. In cuprizone-treated mouse model, massive brain demyelination is followed by spontaneous and robust remyelination. However, reformed myelin, although functional, may not exhibit the same morphological characteristics as developmental myelin, which can have an impact on the activity of neural networks. In this context, we used the cuprizone-treated mouse model to analyze the structural, functional, and cognitive long-term effects of transient demyelination. Our results show that an episode of demyelination induces despite remyelination long-term cognitive impairment, such as deficits in spatial working memory, social memory, cognitive flexibility, and hyperactivity. These deficits were associated with a reduction in myelin content in the medial prefrontal cortex (mPFC) and hippocampus (HPC), as well as structural myelin modifications, suggesting that the remyelination process may be imperfect in these structures. In vivo electrophysiological recordings showed that the demyelination episode altered the synchronization of HPC-mPFC activity, which is crucial for memory processes. Altogether, our data indicate that the myelin repair process following transient demyelination does not allow the complete recovery of the initial myelin properties in cortical structures. These subtle modifications alter network features, leading to prolonged cognitive deficits in mice.
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Affiliation(s)
- Océane Mercier
- UMR7288 after IBDM, Aix Marseille Univ, CNRS, IBDM, Marseille, France
| | - Pascale P Quilichini
- U1106 after INS, Aix Marseille Univ, INSERM, INS, Inst Neurosci Syst, Marseille, France
| | - Karine Magalon
- UMR7288 after IBDM, Aix Marseille Univ, CNRS, IBDM, Marseille, France
| | - Florian Gil
- UMR7288 after IBDM, Aix Marseille Univ, CNRS, IBDM, Marseille, France
| | - Antoine Ghestem
- U1106 after INS, Aix Marseille Univ, INSERM, INS, Inst Neurosci Syst, Marseille, France
| | - Fabrice Richard
- UMR7288 after IBDM, Aix Marseille Univ, CNRS, IBDM, Marseille, France
| | - Thomas Boudier
- Aix Marseille Univ, Turing Centre for Living Systems, Marseille, France
| | - Myriam Cayre
- UMR7288 after IBDM, Aix Marseille Univ, CNRS, IBDM, Marseille, France
| | - Pascale Durbec
- UMR7288 after IBDM, Aix Marseille Univ, CNRS, IBDM, Marseille, France
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5
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Santos E, Huffman WC, Fields RD. Recovery of node of ranvier structure in optic nerve under visual deprivation. Neurosci Res 2024:S0168-0102(24)00050-6. [PMID: 38554941 DOI: 10.1016/j.neures.2024.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 03/01/2024] [Accepted: 03/27/2024] [Indexed: 04/02/2024]
Abstract
Neural activity can increase the length of nodes of Ranvier (NOR) and slow impulse transmission; however, little is known about the biologically and clinically important recovery process. Sensory deprivation promotes neural plasticity in many phenomena, raising the question of whether recovery of NOR morphology is influenced by sensory deprivation. The results show that NOR gap length recovery in mouse optic nerve was not affected significantly by binocular visual deprivation imposed by maintaining mice in 24 hr dark for 30 days compared to mice recovering under normal visual experience. The findings provide insight into the cellular mechanism of NOR plasticity.
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Affiliation(s)
- Erin Santos
- Nervous System Development and Plasticity Section, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH,USA
| | - William C Huffman
- Nervous System Development and Plasticity Section, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH,USA
| | - R Douglas Fields
- Nervous System Development and Plasticity Section, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH,USA.
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6
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Zhou YT, An DD, Xu YX, Zhou Y, Li QQ, Dai HB, Zhang XN, Wang Y, Lou M, Chen Z, Hu WW. Activation of glutamatergic neurons in the somatosensory cortex promotes remyelination in ischemic vascular dementia. FUNDAMENTAL RESEARCH 2024; 4:188-198. [PMID: 38933843 PMCID: PMC11197523 DOI: 10.1016/j.fmre.2022.08.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 07/28/2022] [Accepted: 08/03/2022] [Indexed: 11/29/2022] Open
Abstract
Chronic cerebral hypoperfusion can cause progressive demyelination as well as ischemic vascular dementia, however no effective treatments are available. Here, based on magnetic resonance imaging studies of patients with white matter damage, we found that this damage is associated with disorganized cortical structure. In a mouse model, optogenetic activation of glutamatergic neurons in the somatosensory cortex significantly promoted oligodendrocyte progenitor cell (OPC) proliferation, remyelination in the corpus callosum, and recovery of cognitive ability after cerebral hypoperfusion. The therapeutic effect of such stimulation was restricted to the upper layers of the cortex, but also spanned a wide time window after ischemia. Mechanistically, enhancement of glutamatergic neuron-OPC functional synaptic connections is required to achieve the protection effect of activating cortical glutamatergic neurons. Additionally, skin stroking, an easier method to translate into clinical practice, activated the somatosensory cortex, thereby promoting OPC proliferation, remyelination and cognitive recovery following cerebral hypoperfusion. In summary, we demonstrated that activating glutamatergic neurons in the somatosensory cortex promotes the proliferation of OPCs and remyelination to recover cognitive function after chronic cerebral hypoperfusion. It should be noted that this activation may provide new approaches for treating ischemic vascular dementia via the precise regulation of glutamatergic neuron-OPC circuits.
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Affiliation(s)
- Yi-Ting Zhou
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, College of Pharmaceutical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China
- Department of Pharmacy, Sir Run Run Shaw Hospital, Hangzhou 310012, China
| | - Da-Dao An
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, College of Pharmaceutical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou 310053, China
| | - Yi-Xin Xu
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, College of Pharmaceutical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Ying Zhou
- Department of Neurology, the Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou 310003, China
| | - Qing-Qing Li
- Department of Neurology, the Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou 310003, China
| | - Hai-Bin Dai
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, College of Pharmaceutical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Xiang-Nan Zhang
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, College of Pharmaceutical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Yi Wang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou 310053, China
| | - Min Lou
- Department of Neurology, the Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou 310003, China
| | - Zhong Chen
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, College of Pharmaceutical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou 310053, China
| | - Wei-Wei Hu
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, College of Pharmaceutical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China
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7
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Zhuang H, Li Q, Sun C, Xu D, Gan G, Zhang C, Chen C, Yuan Y, Liu L, Xiao Y, Yao X, Wang C, Kang X, Yang C, Zhao J, Chen W, Wang J, Li J, Luo C, Wang J, Jia X, Yu Z, Liu L. Voluntary wheel exercise ameliorates cognitive impairment, hippocampal neurodegeneration and microglial abnormalities preceded by demyelination in a male mouse model of noise-induced hearing loss. Brain Behav Immun 2023; 114:325-348. [PMID: 37683962 DOI: 10.1016/j.bbi.2023.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 08/23/2023] [Accepted: 09/05/2023] [Indexed: 09/10/2023] Open
Abstract
Acquired peripheral hearing loss (APHL) in midlife has been identified as the greatest modifiable risk factor for dementia; however, the pathophysiological neural mechanisms linking APHL with an increased risk of dementia remain to be elucidated. Here, in an adult male mouse model of noise-induced hearing loss (NIHL), one of the most common forms of APHL, we demonstrated accelerated age-related cognitive decline and hippocampal neurodegeneration during a 6-month follow-up period, accompanied by progressive hippocampal microglial aberrations preceded by immediate-onset transient elevation in serum glucocorticoids and delayed-onset sustained myelin disruption in the hippocampus. Pretreatment with the glucocorticoid receptor antagonist RU486 before stressful noise exposure partially mitigated the early activation of hippocampal microglia, which were present at 7 days post noise exposure (7DPN), but had no impact on later microglial aberrations, hippocampal neurodegeneration, or cognitive decline exhibited at 1 month post noise exposure (1MPN). One month of voluntary wheel exercise following noise exposure barely affected either the hearing threshold shift or hippocampal myelin changes but effectively countered cognitive impairment and the decline in hippocampal neurogenesis in NIHL mice at 1MPN, paralleled by the normalization of microglial morphology, which coincided with a reduction in microglial myelin inclusions and a restoration of microglial hypoxia-inducible factor-1α (HIF1α) expression. Our results indicated that accelerated cognitive deterioration and hippocampal neuroplastic decline following NIHL are most likely driven by the maladaptive response of hippocampal microglia to myelin damage secondary to hearing loss, and we also demonstrated the potential of voluntary physical exercise as a promising and cost-effective strategy to alleviate the detrimental impact of APHL on cognitive function and thus curtail the high and continuously increasing global burden of dementia. Furthermore, the findings of the present study highlight the contribution of myelin debris overload to microglial malfunction and identify the microglial HIF1α-related pathway as an attractive candidate for future comprehensive investigation to obtain a more definitive picture of the underlying mechanisms linking APHL and dementia.
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Affiliation(s)
- Hong Zhuang
- Department of Physiology, School of Medicine, Southeast University, Nanjing 210009, China
| | - Qian Li
- Department of Physiology, School of Medicine, Southeast University, Nanjing 210009, China
| | - Congli Sun
- Department of Physiology, School of Medicine, Southeast University, Nanjing 210009, China
| | - Dan Xu
- School of Public Health, Southeast University, Nanjing 210009, China
| | - Guangming Gan
- School of Medicine, Southeast University, Nanjing 210009, China
| | - Chenchen Zhang
- School of Medicine, Southeast University, Nanjing 210009, China
| | - Chen Chen
- School of Medicine, Southeast University, Nanjing 210009, China
| | - Yang Yuan
- Department of Endocrinology, Zhongda Hospital, Medical School, Southeast University, Nanjing 210009, China
| | - Linchen Liu
- Department of Rheumatology, Zhongda Hospital, School of Medicine, Southeast University, Nanjing 210009, China
| | - Yu Xiao
- Department of Physiology, School of Medicine, Southeast University, Nanjing 210009, China
| | - Xiuting Yao
- Department of Physiology, School of Medicine, Southeast University, Nanjing 210009, China
| | - Conghui Wang
- Department of Physiology, School of Medicine, Southeast University, Nanjing 210009, China
| | - Xiaoming Kang
- School of Life Science and Technology, Southeast University, Nanjing 210009, China
| | - Chenxi Yang
- Department of Physiology, School of Medicine, Southeast University, Nanjing 210009, China
| | - Jingyi Zhao
- School of Life Science and Technology, Southeast University, Nanjing 210009, China
| | - Wenhao Chen
- School of Medicine, Southeast University, Nanjing 210009, China
| | - Jiatang Wang
- School of Medicine, Southeast University, Nanjing 210009, China
| | - Jinyu Li
- School of Medicine, Southeast University, Nanjing 210009, China
| | - Caichen Luo
- School of Medicine, Southeast University, Nanjing 210009, China
| | - Jie Wang
- School of Medicine, Southeast University, Nanjing 210009, China
| | - Xirui Jia
- School of Life Science and Technology, Southeast University, Nanjing 210009, China
| | - Zhehao Yu
- Department of Physiology, School of Medicine, Southeast University, Nanjing 210009, China
| | - Lijie Liu
- Jiangsu Provincial Key Laboratory of Critical Care Medicine, Department of Physiology, School of Medicine, Southeast University, Nanjing 210009, China.
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8
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Caldwell M, Ayo-Jibunoh V, Mendoza JC, Brimblecombe KR, Reynolds LM, Zhu Jiang XY, Alarcon C, Fiore E, N Tomaio J, Phillips GR, Mingote S, Flores C, Casaccia P, Liu J, Cragg SJ, McCloskey DP, Yetnikoff L. Axo-glial interactions between midbrain dopamine neurons and oligodendrocyte lineage cells in the anterior corpus callosum. Brain Struct Funct 2023; 228:1993-2006. [PMID: 37668732 PMCID: PMC10516790 DOI: 10.1007/s00429-023-02695-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 08/09/2023] [Indexed: 09/06/2023]
Abstract
Oligodendrocyte progenitor cells (OPCs) receive synaptic innervation from glutamatergic and GABAergic axons and can be dynamically regulated by neural activity, resulting in activity-dependent changes in patterns of axon myelination. However, it remains unclear to what extent other types of neurons may innervate OPCs. Here, we provide evidence implicating midbrain dopamine neurons in the innervation of oligodendrocyte lineage cells in the anterior corpus callosum and nearby white matter tracts of male and female adult mice. Dopaminergic axon terminals were identified in the corpus callosum of DAT-Cre mice after injection of an eYFP reporter virus into the midbrain. Furthermore, fast-scan cyclic voltammetry revealed monoaminergic transients in the anterior corpus callosum, consistent with the anatomical findings. Using RNAscope, we further demonstrate that ~ 40% of Olig2 + /Pdfgra + cells and ~ 20% of Olig2 + /Pdgfra- cells in the anterior corpus callosum express Drd1 and Drd2 transcripts. These results suggest that oligodendrocyte lineage cells may respond to dopamine released from midbrain dopamine axons, which could affect myelination. Together, this work broadens our understanding of neuron-glia interactions with important implications for myelin plasticity by identifying midbrain dopamine axons as a potential regulator of corpus callosal oligodendrocyte lineage cells.
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Affiliation(s)
- Megan Caldwell
- CUNY Neuroscience Collaborative, The Graduate Center, City University of New York, 365 5Th Ave, New York, NY, 10016, USA
- Department of Psychology, College of Staten Island, City University of New York, 2800 Victory Boulevard, Staten Island, NY, 10314, USA
| | - Vanessa Ayo-Jibunoh
- Department of Psychology, College of Staten Island, City University of New York, 2800 Victory Boulevard, Staten Island, NY, 10314, USA
| | - Josue Criollo Mendoza
- Department of Biology, College of Staten Island, City University of New York, 2800 Victory Boulevard, Staten Island, NY, 10314, USA
| | - Katherine R Brimblecombe
- Centre for Integrative Neuroscience, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, UK
- Oxford Parkinson's Disease Centre, University of Oxford, Oxford, OX1 3PT, UK
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA
| | - Lauren M Reynolds
- Plasticité du Cerveau, CNRS UMR8249, École Supérieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Paris, France
| | - Xin Yan Zhu Jiang
- Department of Biology, College of Staten Island, City University of New York, 2800 Victory Boulevard, Staten Island, NY, 10314, USA
| | - Colin Alarcon
- Department of Psychology, College of Staten Island, City University of New York, 2800 Victory Boulevard, Staten Island, NY, 10314, USA
| | - Elizabeth Fiore
- Department of Psychology, College of Staten Island, City University of New York, 2800 Victory Boulevard, Staten Island, NY, 10314, USA
| | - Jacquelyn N Tomaio
- CUNY Neuroscience Collaborative, The Graduate Center, City University of New York, 365 5Th Ave, New York, NY, 10016, USA
- Neuroscience Initiative, Advanced Science Research Center, Graduate Center of The City University of New York, New York, NY, USA
| | - Greg R Phillips
- CUNY Neuroscience Collaborative, The Graduate Center, City University of New York, 365 5Th Ave, New York, NY, 10016, USA
- Department of Biology, College of Staten Island, City University of New York, 2800 Victory Boulevard, Staten Island, NY, 10314, USA
- Center for Developmental Neuroscience, College of Staten Island, City University of New York, 2800 Victory Boulevard, Staten Island, NY, 10314, USA
| | - Susana Mingote
- CUNY Neuroscience Collaborative, The Graduate Center, City University of New York, 365 5Th Ave, New York, NY, 10016, USA
- Neuroscience Initiative, Advanced Science Research Center, Graduate Center of The City University of New York, New York, NY, USA
| | - Cecilia Flores
- Department of Psychiatry and of Neurology and Neuroscience, McGill University, and Douglas Mental Health University Institute, Montreal, QC, Canada
| | - Patrizia Casaccia
- Neuroscience Initiative, Advanced Science Research Center, Graduate Center of The City University of New York, New York, NY, USA
- Department of Neuroscience and Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Jia Liu
- Neuroscience Initiative, Advanced Science Research Center, Graduate Center of The City University of New York, New York, NY, USA
| | - Stephanie J Cragg
- Centre for Integrative Neuroscience, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, UK
- Oxford Parkinson's Disease Centre, University of Oxford, Oxford, OX1 3PT, UK
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA
| | - Dan P McCloskey
- CUNY Neuroscience Collaborative, The Graduate Center, City University of New York, 365 5Th Ave, New York, NY, 10016, USA
- Department of Psychology, College of Staten Island, City University of New York, 2800 Victory Boulevard, Staten Island, NY, 10314, USA
| | - Leora Yetnikoff
- CUNY Neuroscience Collaborative, The Graduate Center, City University of New York, 365 5Th Ave, New York, NY, 10016, USA.
- Department of Psychology, College of Staten Island, City University of New York, 2800 Victory Boulevard, Staten Island, NY, 10314, USA.
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9
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Shimizu T, Nayar SG, Swire M, Jiang Y, Grist M, Kaller M, Sampaio Baptista C, Bannerman DM, Johansen-Berg H, Ogasawara K, Tohyama K, Li H, Richardson WD. Oligodendrocyte dynamics dictate cognitive performance outcomes of working memory training in mice. Nat Commun 2023; 14:6499. [PMID: 37838794 PMCID: PMC10576739 DOI: 10.1038/s41467-023-42293-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 10/04/2023] [Indexed: 10/16/2023] Open
Abstract
Previous work has shown that motor skill learning stimulates and requires generation of myelinating oligodendrocytes (OLs) from their precursor cells (OLPs) in the brains of adult mice. In the present study we ask whether OL production is also required for non-motor learning and cognition, using T-maze and radial-arm-maze tasks that tax spatial working memory. We find that maze training stimulates OLP proliferation and OL production in the medial prefrontal cortex (mPFC), anterior corpus callosum (genu), dorsal thalamus and hippocampal formation of adult male mice; myelin sheath formation is also stimulated in the genu. Genetic blockade of OL differentiation and neo-myelination in Myrf conditional-knockout mice strongly impairs training-induced improvements in maze performance. We find a strong positive correlation between the performance of individual wild type mice and the scale of OLP proliferation and OL generation during training, but not with the number or intensity of c-Fos+ neurons in their mPFC, underscoring the important role played by OL lineage cells in cognitive processing.
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Affiliation(s)
- Takahiro Shimizu
- Wolfson Institute for Biomedical Research, University College London, Gower Street, London, WC1E 6BT, UK
| | - Stuart G Nayar
- Wolfson Institute for Biomedical Research, University College London, Gower Street, London, WC1E 6BT, UK
| | - Matthew Swire
- Wolfson Institute for Biomedical Research, University College London, Gower Street, London, WC1E 6BT, UK
| | - Yi Jiang
- Wolfson Institute for Biomedical Research, University College London, Gower Street, London, WC1E 6BT, UK
| | - Matthew Grist
- Wolfson Institute for Biomedical Research, University College London, Gower Street, London, WC1E 6BT, UK
| | - Malte Kaller
- Wellcome Centre for Integrative Neuroimaging, Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, UK
| | - Cassandra Sampaio Baptista
- Wellcome Centre for Integrative Neuroimaging, Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, UK
- Institute of Neuroscience and Psychology, University of Glasgow, 62 Hillhead Street, G12 8QB, Glasgow, UK
| | - David M Bannerman
- Department of Experimental Psychology, University of Oxford, Oxford, OX1 3TA, UK
| | - Heidi Johansen-Berg
- Wellcome Centre for Integrative Neuroimaging, Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, UK
| | - Katsutoshi Ogasawara
- Technical Support Center for Life Science Research, Iwate Medical University, 1-1-1 Idaidori, Yahabacho, Shiwa-gun, Morioka, Iwate, 028-3694, Japan
| | - Koujiro Tohyama
- Department of Physiology, Iwate Medical University, 1-1-1 Idaidori, Yahabacho, Shiwa-gun, Morioka, Iwate, 028-3694, Japan
| | - Huiliang Li
- Wolfson Institute for Biomedical Research, University College London, Gower Street, London, WC1E 6BT, UK
| | - William D Richardson
- Wolfson Institute for Biomedical Research, University College London, Gower Street, London, WC1E 6BT, UK.
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10
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Moura D, Parvathaneni A, Sahagun A, Noguchi H, Garcia J, Brennan E, Brock R, Tilton I, Halladay L, Pleasure S, Cocas L. Neuronal Activity Changes the Number of Neurons That Are Synaptically Connected to OPCs. eNeuro 2023; 10:ENEURO.0126-23.2023. [PMID: 37813563 PMCID: PMC10598642 DOI: 10.1523/eneuro.0126-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 08/11/2023] [Accepted: 08/18/2023] [Indexed: 10/17/2023] Open
Abstract
The timing and specificity of oligodendrocyte myelination during development, as well as remyelination after injury or immune attack, remain poorly understood. Recent work has shown that oligodendrocyte progenitors receive synapses from neurons, providing a potential mechanism for neuronal-glial communication. In this study, we investigated the importance of these neuroglial connections in myelination during development and during neuronal plasticity in the mouse hippocampus. We used chemogenetic tools and viral monosynaptic circuit tracing to analyze these connections and to examine oligodendrocyte progenitor cells (OPCs) proliferation, myelination, synapse formation, and neuronal-glial connectivity in vivo after increasing or decreasing neuronal activity levels. We found that increasing neuronal activity led to greater OPC activation and proliferation. Modulation of neuronal activity also altered the organization of neuronal-glial connections: while it did not impact the total number of RabV-labeled neuronal inputs, or the number of RabV-labeled inhibitory neuronal (IN) inputs, it did alter the number of RabV-labeled excitatory neuron to OPC connections. Overall, our findings support the idea that neuronal activity plays a crucial role in regulating OPC proliferation and activation as well as the types of neuronal inputs to OPCs, indicating that neuronal activity is important for OPC circuit composition and function.
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Affiliation(s)
- Daniela Moura
- Biology Department, Neuroscience Program, Santa Clara University, Santa Clara, CA 95053
- Neurology Department, University of California, San Francisco, San Francisco, CA 94110
| | - Alekhya Parvathaneni
- Biology Department, Neuroscience Program, Santa Clara University, Santa Clara, CA 95053
| | - Atehsa Sahagun
- Biology Department, Neuroscience Program, Santa Clara University, Santa Clara, CA 95053
| | - Hirofumi Noguchi
- Neurology Department, University of California, San Francisco, San Francisco, CA 94110
| | - Jesse Garcia
- Neurology Department, University of California, San Francisco, San Francisco, CA 94110
| | - Emma Brennan
- Biology Department, Neuroscience Program, Santa Clara University, Santa Clara, CA 95053
| | - Robert Brock
- Biology Department, Neuroscience Program, Santa Clara University, Santa Clara, CA 95053
| | - Iris Tilton
- Biology Department, Neuroscience Program, Santa Clara University, Santa Clara, CA 95053
| | - Lindsay Halladay
- Biology Department, Neuroscience Program, Santa Clara University, Santa Clara, CA 95053
| | - Samuel Pleasure
- Neurology Department, University of California, San Francisco, San Francisco, CA 94110
| | - Laura Cocas
- Biology Department, Neuroscience Program, Santa Clara University, Santa Clara, CA 95053
- Neurology Department, University of California, San Francisco, San Francisco, CA 94110
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11
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Kondiles B, Murphy R, Widman A, Perlmutter S, Horner P. Cortical stimulation leads to shortened myelin sheaths and increased axonal branching in spared axons after cervical spinal cord injury. Glia 2023; 71:1947-1959. [PMID: 37096399 PMCID: PMC10649492 DOI: 10.1002/glia.24376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 03/28/2023] [Accepted: 04/02/2023] [Indexed: 04/26/2023]
Abstract
Neural activity and learning lead to myelin sheath plasticity in the intact central nervous system (CNS), but this plasticity has not been well-studied after CNS injury. In the context of spinal cord injury (SCI), demyelination occurs at the lesion site and natural remyelination of surviving axons can take months. To determine if neural activity modulates myelin and axon plasticity in the injured, adult CNS, we electrically stimulated the contralesional motor cortex at 10 Hz to drive neural activity in the corticospinal tract of rats with sub-chronic spinal contusion injuries. We quantified myelin and axonal characteristics by tracing corticospinal axons rostral to and at the lesion epicenter and identifying nodes of Ranvier by immunohistochemistry. Three weeks of daily stimulation induced very short myelin sheaths, axon branching, and thinner axons outside of the lesion zone, where remodeling has not previously been reported. Surprisingly, remodeling was particularly robust rostral to the injury which suggests that electrical stimulation can promote white matter plasticity even in areas not directly demyelinated by the contusion. Stimulation did not alter myelin or axons at the lesion site, which suggests that neuronal activity does not contribute to myelin remodeling near the injury in the sub-chronic period. These data are the first to demonstrate wide-scale remodeling of nodal and myelin structures of a mature, long-tract motor pathway in response to electrical stimulation. This finding suggests that neuromodulation promotes white matter plasticity in intact regions of pathways after injury and raises intriguing questions regarding the interplay between axonal and myelin plasticity.
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Affiliation(s)
- B.R. Kondiles
- Department of Physiology and Biophysics, University of Washington, 1705 NE Pacific St. Seattle, WA, 98105, USA
- Center for Neuroregeneration, Dept. of Neurosurgery, Houston Methodist Research Institute, 6670 Bertner, Houston, TX, 77030, USA
| | - R.L. Murphy
- Department of Physiology and Biophysics, University of Washington, 1705 NE Pacific St. Seattle, WA, 98105, USA
| | - A.J. Widman
- Department of Physiology and Biophysics, University of Washington, 1705 NE Pacific St. Seattle, WA, 98105, USA
| | - S.I. Perlmutter
- Department of Physiology and Biophysics, University of Washington, 1705 NE Pacific St. Seattle, WA, 98105, USA
| | - P.J. Horner
- Center for Neuroregeneration, Dept. of Neurosurgery, Houston Methodist Research Institute, 6670 Bertner, Houston, TX, 77030, USA
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12
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Balraj A, Clarkson-Paredes C, Miller RH. Loss of optic nerve oligodendrocytes during maturation alters retinal organization. Exp Eye Res 2023:109540. [PMID: 37364629 DOI: 10.1016/j.exer.2023.109540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 06/01/2023] [Accepted: 06/12/2023] [Indexed: 06/28/2023]
Abstract
The myelin sheath facilitates signal conduction along axons in white matter tracts, and when disrupted, can result in significant functional deficits. Demyelination, observed in diseases like multiple sclerosis and optic neuritis, are associated with neural degeneration, however the extent of this damage on upstream circuitry is not well understood. Here we use the MBP-iCP9 mouse model to induce selective oligodendrocyte ablation in the optic nerve at P14 via a chemical inducer of dimerization (CID), resulting in partial demyelination of retinal ganglion cell (RGC) axons with minimal inflammation after two weeks. Oligodendrocyte loss reduced axon diameter and altered compound action potential waveforms, blocking conduction in the slowest-conducting axon populations. Demyelination resulted in disruptions to the normal composition of the retina, including reduced density of RBPMS+, Brn3a+, and OFF-transient RGCs, thinning of the IPL, and reduced density of displaced amacrine cells. The INL and ONL were unaffected by oligodendrocyte loss, suggesting that demyelination-induced deficits in this model are specific to the IPL and GCL. These results show that a partial demyelination of a subpopulation of RGC axons disrupts optic nerve function and affects the organization of the retinal network. This study highlights the significance of myelination in maintaining upstream neural connectivity and provides support for targeting neuronal degeneration in treatments of demyelinating diseases.
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Affiliation(s)
- Annika Balraj
- Department of Anatomy and Cell Biology, The George Washington University, School of Medicine and Health Sciences, Washington, D.C., USA
| | - Cheryl Clarkson-Paredes
- Department of Anatomy and Cell Biology, The George Washington University, School of Medicine and Health Sciences, Washington, D.C., USA
| | - Robert H Miller
- Department of Anatomy and Cell Biology, The George Washington University, School of Medicine and Health Sciences, Washington, D.C., USA.
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13
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Masson MA, Nait-Oumesmar B. Emerging concepts in oligodendrocyte and myelin formation, inputs from the zebrafish model. Glia 2023; 71:1147-1163. [PMID: 36645033 DOI: 10.1002/glia.24336] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/20/2022] [Accepted: 12/29/2022] [Indexed: 01/17/2023]
Abstract
Oligodendrocytes (OLs) are the myelinating cells of the central nervous system (CNS), which are derived from OL precursor cells. Myelin insulates axons allowing the saltatory conduction of action potentials and also provides trophic and metabolic supports to axons. Interestingly, oligodendroglial cells have the capacity to sense neuronal activity, which regulates myelin sheath formation via the vesicular release of neurotransmitters. Neuronal activity-dependent regulation of myelination is mediated by specialized interaction between axons and oligodendroglia, involving both synaptic and extra-synaptic modes of communications. The zebrafish has provided key advantages for the study of the myelination process in the CNS. External development and transparent larval stages of this vertebrate specie combined with the existence of several transgenic reporter lines provided key advances in oligodendroglial cell biology, axo-glial interactions and CNS myelination. In this publication, we reviewed and discussed the most recent knowledge on OL development and myelin formation, with a focus on mechanisms regulating these fundamental biological processes in the zebrafish. Especially, we highlighted the critical function of axons and oligodendroglia modes of communications and calcium signaling in myelin sheath formation and growth. Finally, we reviewed the relevance of these knowledge's in demyelinating diseases and drug discovery of pharmacological compounds favoring myelin regeneration.
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Affiliation(s)
- Mary-Amélie Masson
- Sorbonne Université, Institut du Cerveau, Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Brahim Nait-Oumesmar
- Sorbonne Université, Institut du Cerveau, Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié-Salpêtrière, Paris, France
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14
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Jiang L, Li F, Chen Z, Zhu B, Yi C, Li Y, Zhang T, Peng Y, Si Y, Cao Z, Chen A, Yao D, Chen X, Xu P. Information transmission velocity-based dynamic hierarchical brain networks. Neuroimage 2023; 270:119997. [PMID: 36868393 DOI: 10.1016/j.neuroimage.2023.119997] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 02/09/2023] [Accepted: 02/27/2023] [Indexed: 03/05/2023] Open
Abstract
The brain functions as an accurate circuit that regulates information to be sequentially propagated and processed in a hierarchical manner. However, it is still unknown how the brain is hierarchically organized and how information is dynamically propagated during high-level cognition. In this study, we developed a new scheme for quantifying the information transmission velocity (ITV) by combining electroencephalogram (EEG) and diffusion tensor imaging (DTI), and then mapped the cortical ITV network (ITVN) to explore the information transmission mechanism of the human brain. The application in MRI-EEG data of P300 revealed bottom-up and top-down ITVN interactions subserving P300 generation, which was comprised of four hierarchical modules. Among these four modules, information exchange between visual- and attention-activated regions occurred at a high velocity, related cognitive processes could thus be efficiently accomplished due to the heavy myelination of these regions. Moreover, inter-individual variability in P300 was probed to be attributed to the difference in information transmission efficiency of the brain, which may provide new insight into the cognitive degenerations in clinical neurodegenerative disorders, such as Alzheimer's disease, from the transmission velocity perspective. Together, these findings confirm the capacity of ITV to effectively determine the efficiency of information propagation in the brain.
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Affiliation(s)
- Lin Jiang
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, No.2006, Xiyuan Ave, West Hi-Tech Zone, Chengdu, Sichuan 611731, China; School of Life Science and Technology, Center for Information in BioMedicine, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Fali Li
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, No.2006, Xiyuan Ave, West Hi-Tech Zone, Chengdu, Sichuan 611731, China; School of Life Science and Technology, Center for Information in BioMedicine, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Zhaojin Chen
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, No.2006, Xiyuan Ave, West Hi-Tech Zone, Chengdu, Sichuan 611731, China; School of Life Science and Technology, Center for Information in BioMedicine, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Bin Zhu
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, No.2006, Xiyuan Ave, West Hi-Tech Zone, Chengdu, Sichuan 611731, China; School of Life Science and Technology, Center for Information in BioMedicine, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Chanlin Yi
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, No.2006, Xiyuan Ave, West Hi-Tech Zone, Chengdu, Sichuan 611731, China; School of Life Science and Technology, Center for Information in BioMedicine, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Yuqin Li
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, No.2006, Xiyuan Ave, West Hi-Tech Zone, Chengdu, Sichuan 611731, China; School of Life Science and Technology, Center for Information in BioMedicine, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Tao Zhang
- School of science, Xihua University, Chengdu 610039, China
| | - Yueheng Peng
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, No.2006, Xiyuan Ave, West Hi-Tech Zone, Chengdu, Sichuan 611731, China; School of Life Science and Technology, Center for Information in BioMedicine, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Yajing Si
- School of Psychology, Xinxiang Medical University, Xinxiang 453003, China
| | - Zehong Cao
- STEM, University of South Australia, Adelaide, SA 5000, Australia
| | - Antao Chen
- Faculty of Psychology, Southwest University, Chongqing 400715, China
| | - Dezhong Yao
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, No.2006, Xiyuan Ave, West Hi-Tech Zone, Chengdu, Sichuan 611731, China; School of Life Science and Technology, Center for Information in BioMedicine, University of Electronic Science and Technology of China, Chengdu 611731, China; School of Electrical Engineering, Zhengzhou University, Zhengzhou 450001, China; Research Unit of NeuroInformation, Chinese Academy of Medical Sciences, Chengdu 2019RU035, China.
| | - Xun Chen
- Department of Neurosurgery, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230001, China; Department of Electronic Engineering and Information Science, University of Science and Technology of China, Hefei 230026, China.
| | - Peng Xu
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, No.2006, Xiyuan Ave, West Hi-Tech Zone, Chengdu, Sichuan 611731, China; School of Life Science and Technology, Center for Information in BioMedicine, University of Electronic Science and Technology of China, Chengdu 611731, China.
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15
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Early growth response 2 in the mPFC regulates mouse social and cooperative behaviors. Lab Anim (NY) 2023; 52:37-50. [PMID: 36646797 DOI: 10.1038/s41684-022-01090-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 11/14/2022] [Indexed: 01/18/2023]
Abstract
Adolescent social neglect impairs social performance, but the underlying molecular mechanisms remain unclear. Here we report that isolation rearing of juvenile mice caused cooperation defects that were rescued by immediate social reintroduction. We also identified the transcription factor early growth response 2 (Egr2) in the medial prefrontal cortex (mPFC) as a major target of social isolation and resocialization. Isolation rearing increased corticosteroid production, which reduced the expression of Egr2 in the mPFC, including in oligodendrocytes. Overexpressing Egr2 ubiquitously in the mPFC, but not specifically in neurons nor in oligodendroglia, protected mice from the isolation rearing-induced cooperation defect. In addition to synapse integrity, Egr2 also regulated the development of oligodendroglia, specifically the transition from undifferentiated oligodendrocyte precursor cells to premyelinating oligodendrocytes. In conclusion, this study reveals the importance of mPFC Egr2 in the cooperative behavior that is modulated by social experience, and its unexpected role in oligodendrocyte development.
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16
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Djannatian M, Radha S, Weikert U, Safaiyan S, Wrede C, Deichsel C, Kislinger G, Rhomberg A, Ruhwedel T, Campbell DS, van Ham T, Schmid B, Hegermann J, Möbius W, Schifferer M, Simons M. Myelination generates aberrant ultrastructure that is resolved by microglia. J Biophys Biochem Cytol 2023; 222:213804. [PMID: 36637807 PMCID: PMC9856851 DOI: 10.1083/jcb.202204010] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 10/18/2022] [Accepted: 12/21/2022] [Indexed: 01/14/2023] Open
Abstract
To enable rapid propagation of action potentials, axons are ensheathed by myelin, a multilayered insulating membrane formed by oligodendrocytes. Most of the myelin is generated early in development, resulting in the generation of long-lasting stable membrane structures. Here, we explored structural and dynamic changes in central nervous system myelin during development. To achieve this, we performed an ultrastructural analysis of mouse optic nerves by serial block face scanning electron microscopy (SBF-SEM) and confocal time-lapse imaging in the zebrafish spinal cord. We found that myelin undergoes extensive ultrastructural changes during early postnatal development. Myelin degeneration profiles were engulfed and phagocytosed by microglia using exposed phosphatidylserine as one "eat me" signal. In contrast, retractions of entire myelin sheaths occurred independently of microglia and involved uptake of myelin by the oligodendrocyte itself. Our findings show that the generation of myelin early in development is an inaccurate process associated with aberrant ultrastructural features that require substantial refinement.
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Affiliation(s)
- Minou Djannatian
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany,https://ror.org/043j0f473German Center for Neurodegenerative Diseases, Munich, Germany,Department of Neurology, Klinikum rechts der Isar, TUM School of Medicine, Technical University of Munich, Munich, Germany,Munich Cluster of Systems Neurology (SyNergy), Munich, Germany,Minou Djannatian:
| | - Swathi Radha
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany,https://ror.org/043j0f473German Center for Neurodegenerative Diseases, Munich, Germany
| | - Ulrich Weikert
- Max-Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Shima Safaiyan
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany,https://ror.org/043j0f473German Center for Neurodegenerative Diseases, Munich, Germany
| | - Christoph Wrede
- https://ror.org/00f2yqf98Institute of Functional and Applied Anatomy, Research Core Unit Electron Microscopy, Hannover Medical School, Hannover, Germany
| | - Cassandra Deichsel
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany,https://ror.org/043j0f473German Center for Neurodegenerative Diseases, Munich, Germany
| | - Georg Kislinger
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany,https://ror.org/043j0f473German Center for Neurodegenerative Diseases, Munich, Germany
| | - Agata Rhomberg
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany,https://ror.org/043j0f473German Center for Neurodegenerative Diseases, Munich, Germany
| | - Torben Ruhwedel
- Max-Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Douglas S. Campbell
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany,https://ror.org/043j0f473German Center for Neurodegenerative Diseases, Munich, Germany
| | - Tjakko van Ham
- https://ror.org/018906e22Department of Clinical Genetics, Erasmus University Medical Center, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Bettina Schmid
- https://ror.org/043j0f473German Center for Neurodegenerative Diseases, Munich, Germany
| | - Jan Hegermann
- https://ror.org/00f2yqf98Institute of Functional and Applied Anatomy, Research Core Unit Electron Microscopy, Hannover Medical School, Hannover, Germany
| | - Wiebke Möbius
- Max-Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Martina Schifferer
- https://ror.org/043j0f473German Center for Neurodegenerative Diseases, Munich, Germany,Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
| | - Mikael Simons
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany,https://ror.org/043j0f473German Center for Neurodegenerative Diseases, Munich, Germany,Munich Cluster of Systems Neurology (SyNergy), Munich, Germany,Institute for Stroke and Dementia Research, University Hospital of Munich, Ludwig Maximilian University of Munich, Munich, Germany,Correspondence to Mikael Simons:
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17
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Cristobal CD, Lee HK. Development of myelinating glia: An overview. Glia 2022; 70:2237-2259. [PMID: 35785432 PMCID: PMC9561084 DOI: 10.1002/glia.24238] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 06/24/2022] [Accepted: 06/24/2022] [Indexed: 01/07/2023]
Abstract
Myelin is essential to nervous system function, playing roles in saltatory conduction and trophic support. Oligodendrocytes (OLs) and Schwann cells (SCs) form myelin in the central and peripheral nervous systems respectively and follow different developmental paths. OLs are neural stem-cell derived and follow an intrinsic developmental program resulting in a largely irreversible differentiation state. During embryonic development, OL precursor cells (OPCs) are produced in distinct waves originating from different locations in the central nervous system, with a subset developing into myelinating OLs. OPCs remain evenly distributed throughout life, providing a population of responsive, multifunctional cells with the capacity to remyelinate after injury. SCs derive from the neural crest, are highly dependent on extrinsic signals, and have plastic differentiation states. SC precursors (SCPs) are produced in early embryonic nerve structures and differentiate into multipotent immature SCs (iSCs), which initiate radial sorting and differentiate into myelinating and non-myelinating SCs. Differentiated SCs retain the capacity to radically change phenotypes in response to external signals, including becoming repair SCs, which drive peripheral regeneration. While several transcription factors and myelin components are common between OLs and SCs, their differentiation mechanisms are highly distinct, owing to their unique lineages and their respective environments. In addition, both OLs and SCs respond to neuronal activity and regulate nervous system output in reciprocal manners, possibly through different pathways. Here, we outline their basic developmental programs, mechanisms regulating their differentiation, and recent advances in the field.
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Affiliation(s)
- Carlo D. Cristobal
- Integrative Program in Molecular and Biomedical SciencesBaylor College of MedicineHoustonTexasUSA,Jan and Dan Duncan Neurological Research InstituteTexas Children's HospitalHoustonTexasUSA
| | - Hyun Kyoung Lee
- Integrative Program in Molecular and Biomedical SciencesBaylor College of MedicineHoustonTexasUSA,Jan and Dan Duncan Neurological Research InstituteTexas Children's HospitalHoustonTexasUSA,Department of PediatricsBaylor College of MedicineHoustonTexasUSA,Department of NeuroscienceBaylor College of MedicineHoustonTexasUSA
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18
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Nicholson M, Wood RJ, Gonsalvez DG, Hannan AJ, Fletcher JL, Xiao J, Murray SS. Remodelling of myelinated axons and oligodendrocyte differentiation is stimulated by environmental enrichment in the young adult brain. Eur J Neurosci 2022; 56:6099-6114. [PMID: 36217300 PMCID: PMC10092722 DOI: 10.1111/ejn.15840] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 09/30/2022] [Accepted: 10/05/2022] [Indexed: 12/29/2022]
Abstract
Oligodendrocyte production and myelination continues lifelong in the central nervous system (CNS), and all stages of this process can be adaptively regulated by neuronal activity. While artificial exogenous stimulation of neuronal circuits greatly enhances oligodendrocyte progenitor cell (OPC) production and increases myelination during development, the extent to which physiological stimuli replicates this is unclear, particularly in the adult CNS when the rate of new myelin addition slows. Here, we used environmental enrichment (EE) to physiologically stimulate neuronal activity for 6 weeks in 9-week-old C57BL/six male and female mice and found no increase in compact myelin in the corpus callosum or somatosensory cortex. Instead, we observed a global increase in callosal axon diameter with thicker myelin sheaths, elongated paranodes and shortened nodes of Ranvier. These findings indicate that EE induced the dynamic structural remodelling of myelinated axons. Additionally, we observed a global increase in the differentiation of OPCs and pre-myelinating oligodendroglia in the corpus callosum and somatosensory cortex. Our findings of structural remodelling of myelinated axons in response to physiological neural stimuli during young adulthood provide important insights in understanding experience-dependent myelin plasticity throughout the lifespan and provide a platform to investigate axon-myelin interactions in a physiologically relevant context.
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Affiliation(s)
- Madeline Nicholson
- Department of Anatomy and Physiology, University of Melbourne, Parkville, Australia
| | - Rhiannon J Wood
- Department of Anatomy and Physiology, University of Melbourne, Parkville, Australia
| | - David G Gonsalvez
- Department of Anatomy and Physiology, University of Melbourne, Parkville, Australia.,Department of Anatomy and Developmental Biology, Monash University, Clayton, Australia
| | - Anthony J Hannan
- Department of Anatomy and Physiology, University of Melbourne, Parkville, Australia.,Florey Institute of Neuroscience and Mental Health, Parkville, Australia
| | - Jessica L Fletcher
- Department of Anatomy and Physiology, University of Melbourne, Parkville, Australia.,Menzies Institute of Medical Research, University of Tasmania, Hobart, Australia
| | - Junhua Xiao
- School of Health Sciences, Swinburne University of Technology, Hawthorn, Victoria, Australia.,School of Allied Health, La Trobe University, Bundoora, Victoria, Australia
| | - Simon S Murray
- Department of Anatomy and Physiology, University of Melbourne, Parkville, Australia.,Florey Institute of Neuroscience and Mental Health, Parkville, Australia
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19
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Dettman RW, Dizon MLV. How lung injury and therapeutic oxygen could alter white matter development. J Neurosci Res 2022; 100:2127-2137. [PMID: 33687103 PMCID: PMC8426430 DOI: 10.1002/jnr.24816] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 02/05/2021] [Accepted: 02/08/2021] [Indexed: 01/07/2023]
Abstract
Developmental brain injury describes a spectrum of neurological pathologies resulting from either antenatal or perinatal injury. This includes both cognitive and motor defects that affect patients for their entire lives. Developmental brain injury can be caused by a spectrum of conditions including stroke, perinatal hypoxia-ischemia, and intracranial hemorrhage. Additional risk factors have been identified including very low birth weight, mechanical ventilation, and oxygen (O2 ) supplementation. In fact, infants with bronchopulmonary dysplasia, an inflammatory disease associated with disrupted lung development, have been shown to have decreased cerebral white matter and decreased intracranial volumes. Thus, there appears to be a developmental link between the lung, O2 , and the brain that leads to proper myelination. Here, we will discuss what is currently known about the link between O2 and myelination and how scientists are exploring mechanisms through which supplemental O2 and/or lung injury can affect brain development. Consideration of a link between the diseased lung and developing brain will allow clinicians to fine tune their approaches in managing preterm lung disease in order to optimize brain health.
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Affiliation(s)
- Robert W. Dettman
- Perinatal Origins of Disease, Stanley Manne Children’s Research Institute, Chicago, IL 60611
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago IL, 60611
| | - Maria L. V. Dizon
- Perinatal Origins of Disease, Stanley Manne Children’s Research Institute, Chicago, IL 60611
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago IL, 60611
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20
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A macroscopic link between interhemispheric tract myelination and cortico-cortical interactions during action reprogramming. Nat Commun 2022; 13:4253. [PMID: 35869067 PMCID: PMC9307658 DOI: 10.1038/s41467-022-31687-5] [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: 03/15/2021] [Accepted: 06/16/2022] [Indexed: 11/15/2022] Open
Abstract
Myelination has been increasingly implicated in the function and dysfunction of the adult human brain. Although it is known that axon myelination shapes axon physiology in animal models, it is unclear whether a similar principle applies in the living human brain, and at the level of whole axon bundles in white matter tracts. Here, we hypothesised that in humans, cortico-cortical interactions between two brain areas may be shaped by the amount of myelin in the white matter tract connecting them. As a test bed for this hypothesis, we use a well-defined interhemispheric premotor-to-motor circuit. We combined TMS-derived physiological measures of cortico-cortical interactions during action reprogramming with multimodal myelin markers (MT, R1, R2* and FA), in a large cohort of healthy subjects. We found that physiological metrics of premotor-to-motor interaction are broadly associated with multiple myelin markers, suggesting interindividual differences in tract myelination may play a role in motor network physiology. Moreover, we also demonstrate that myelination metrics link indirectly to action switching by influencing local primary motor cortex dynamics. These findings suggest that myelination levels in white matter tracts may influence millisecond-level cortico-cortical interactions during tasks. They also unveil a link between the physiology of the motor network and the myelination of tracts connecting its components, and provide a putative mechanism mediating the relationship between brain myelination and human behaviour. Myelination is a key regulator of brain function. Here the authors use MR-based myelin measures to examine if cortico-cortical interactions, as assessed by paired pulse transcranial magnetic stimulation, are affected by variations in myelin in the human brain.
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21
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Lysko DE, Talbot WS. Unmyelinated sensory neurons use Neuregulin signals to promote myelination of interneurons in the CNS. Cell Rep 2022; 41:111669. [PMID: 36384112 PMCID: PMC9719401 DOI: 10.1016/j.celrep.2022.111669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 09/06/2022] [Accepted: 10/25/2022] [Indexed: 11/17/2022] Open
Abstract
The signaling mechanisms neurons use to modulate myelination of circuits in the central nervous system (CNS) are only partly understood. Through analysis of isoform-specific neuregulin1 (nrg1) mutants in zebrafish, we demonstrate that nrg1 type II is an important regulator of myelination of two classes of spinal cord interneurons. Surprisingly, nrg1 type II expression is prominent in unmyelinated Rohon-Beard sensory neurons, whereas myelination of neighboring interneurons is reduced in nrg1 type II mutants. Cell-type-specific loss-of-function studies indicate that nrg1 type II is required in Rohon-Beard neurons to signal to other neurons, not oligodendrocytes, to modulate spinal cord myelination. Together, our data support a model in which unmyelinated neurons express Nrg1 type II proteins to regulate myelination of neighboring neurons, a mode of action that may coordinate the functions of unmyelinated and myelinated neurons in the CNS.
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Affiliation(s)
- Daniel E Lysko
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA
| | - William S Talbot
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA.
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22
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Fekete CD, Nishiyama A. Presentation and integration of multiple signals that modulate oligodendrocyte lineage progression and myelination. Front Cell Neurosci 2022; 16:1041853. [PMID: 36451655 PMCID: PMC9701731 DOI: 10.3389/fncel.2022.1041853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 10/17/2022] [Indexed: 11/15/2022] Open
Abstract
Myelination is critical for fast saltatory conduction of action potentials. Recent studies have revealed that myelin is not a static structure as previously considered but continues to be made and remodeled throughout adulthood in tune with the network requirement. Synthesis of new myelin requires turning on the switch in oligodendrocytes (OL) to initiate the myelination program that includes synthesis and transport of macromolecules needed for myelin production as well as the metabolic and other cellular functions needed to support this process. A significant amount of information is available regarding the individual intrinsic and extrinsic signals that promote OL commitment, expansion, terminal differentiation, and myelination. However, it is less clear how these signals are made available to OL lineage cells when needed, and how multiple signals are integrated to generate the correct amount of myelin that is needed in a given neural network state. Here we review the pleiotropic effects of some of the extracellular signals that affect myelination and discuss the cellular processes used by the source cells that contribute to the variation in the temporal and spatial availability of the signals, and how the recipient OL lineage cells might integrate the multiple signals presented to them in a manner dialed to the strength of the input.
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23
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Effects of Visual Deprivation on Remodeling of Nodes of Ranvier in Optic Nerve. eNeuro 2022; 9:ENEURO.0194-22.2022. [PMID: 36302632 PMCID: PMC9651206 DOI: 10.1523/eneuro.0194-22.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 09/28/2022] [Accepted: 10/05/2022] [Indexed: 12/24/2022] Open
Abstract
Oligodendrocytes, the myelinating cells of the CNS, promote rapid action potential conduction along axons. Changes in the geometry of gaps between myelin segments, known as nodes of Ranvier, affect the conduction speed of neuronal impulses and can ultimately alter neural synchronization and circuit function. In contrast to synaptic plasticity, much less is known about how neural activity may affect node of Ranvier structure. Recently, perinodal astrocytes have been shown to remodel nodes of Ranvier by regulating thrombin proteolysis, but it is not known whether neural activity influences this process. To test this hypothesis, we used transgenic mice with astrocytic expression of a dominant-negative vesicle-associated membrane protein 2 ([gfap]dnVAMP2) to reduce exocytosis of thrombin inhibitors, modulating astrocytic regulation of paranodal loop attachment to induce nodal remodeling, under normal conditions and in adult mice maintained in darkness from postnatal day 40 (P40) to P70. This mechanism of nodal lengthening proceeded normally following binocular visual deprivation (BVD). The effect of BVD on nodal plasticity in animals with unimpaired astrocyte function has not been previously investigated. We find that when exocytosis from astrocytes was unimpaired, nodal gap length was not altered by BVD in adult mice. We conclude that if perinodal astrocytes participate in activity-dependent myelin remodeling through exocytosis, then, as with synaptic plasticity in the visual system, the process must be driven by alterations in neuronal firing other than those produced by BVD.
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24
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Osanai Y, Yamazaki R, Shinohara Y, Ohno N. Heterogeneity and regulation of oligodendrocyte morphology. Front Cell Dev Biol 2022; 10:1030486. [PMID: 36393856 PMCID: PMC9644283 DOI: 10.3389/fcell.2022.1030486] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 10/10/2022] [Indexed: 09/24/2023] Open
Abstract
Oligodendrocytes form multiple myelin sheaths in the central nervous system (CNS), which increase nerve conduction velocity and are necessary for basic and higher brain functions such as sensory function, motor control, and learning. Structures of the myelin sheath such as myelin internodal length and myelin thickness regulate nerve conduction. Various parts of the central nervous system exhibit different myelin structures and oligodendrocyte morphologies. Recent studies supported that oligodendrocytes are a heterogenous population of cells and myelin sheaths formed by some oligodendrocytes can be biased to particular groups of axons, and myelin structures are dynamically modulated in certain classes of neurons by specific experiences. Structures of oligodendrocyte/myelin are also affected in pathological conditions such as demyelinating and neuropsychiatric disorders. This review summarizes our understanding of heterogeneity and regulation of oligodendrocyte morphology concerning central nervous system regions, neuronal classes, experiences, diseases, and how oligodendrocytes are optimized to execute central nervous system functions.
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Affiliation(s)
- Yasuyuki Osanai
- Department of Anatomy, Division of Histology and Cell Biology, School of Medicine, Jichi Medical University, Shimotsuke, Japan
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, Australia
| | - Reiji Yamazaki
- Department of Anatomy, Division of Histology and Cell Biology, School of Medicine, Jichi Medical University, Shimotsuke, Japan
| | - Yoshiaki Shinohara
- Department of Anatomy, Division of Histology and Cell Biology, School of Medicine, Jichi Medical University, Shimotsuke, Japan
- Department of Anatomy and Cell Biology, Faculty of Medicine, University of Yamanashi, Chuo, Japan
| | - Nobuhiko Ohno
- Department of Anatomy, Division of Histology and Cell Biology, School of Medicine, Jichi Medical University, Shimotsuke, Japan
- Division of Ultrastructural Research, National Institute for Physiological Sciences, Okazaki, Japan
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25
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Pan Y, Monje M. Neuron-Glial Interactions in Health and Brain Cancer. Adv Biol (Weinh) 2022; 6:e2200122. [PMID: 35957525 PMCID: PMC9845196 DOI: 10.1002/adbi.202200122] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 06/21/2022] [Indexed: 01/28/2023]
Abstract
Brain tumors are devastating diseases of the central nervous system. Brain tumor pathogenesis depends on both tumor-intrinsic oncogenic programs and extrinsic microenvironmental factors, including neurons and glial cells. Glial cells (oligodendrocytes, astrocytes, and microglia) make up half of the cells in the brain, and interact with neurons to modulate neurodevelopment and plasticity. Many brain tumor cells exhibit transcriptomic profiles similar to macroglial cells (oligodendrocytes and astrocytes) and their progenitors, making them likely to subvert existing neuron-glial interactions to support tumor pathogenesis. For example, oligodendrocyte precursor cells, a putative glioma cell of origin, can form bona fide synapses with neurons. Such synapses are recently identified in gliomas and drive glioma pathophysiology, underscoring how brain tumor cells can take advantage of neuron-glial interactions to support cancer progression. In this review, it is briefly summarized how neurons and their activity normally interact with glial cells and glial progenitors, and it is discussed how brain tumor cells utilize neuron-glial interactions to support tumor initiation and progression. Unresolved questions on these topics and potential avenues to therapeutically target neuron-glia-cancer interactions in the brain are also pointed out.
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Affiliation(s)
- Yuan Pan
- Department of Symptom Research, University of Texas MD Anderson Cancer Center,co-corresponding: ;
| | - Michelle Monje
- Department of Neurology, Stanford University,Howard Hughes Medical Institute, Stanford University,co-corresponding: ;
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26
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A multifaceted gradient in human cerebellum of structural and functional development. Nat Neurosci 2022; 25:1129-1133. [PMID: 35982153 DOI: 10.1038/s41593-022-01136-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 07/11/2022] [Indexed: 11/08/2022]
Abstract
The organization of the basic tissue and functional properties of the cerebellum across development is unknown. Combining several large datasets, we demonstrate in the human cerebellum a static tissue gradient in adults that mirrors a similar growth-rate gradient across development. Quantitative tissue metrics corroborate unique densities of certain lipids and proteins among lobules, and cerebellar structural development closely follows cerebellar functional properties through childhood.
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27
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Osanai Y, Battulga B, Yamazaki R, Kouki T, Yatabe M, Mizukami H, Kobayashi K, Shinohara Y, Yoshimura Y, Ohno N. Dark Rearing in the Visual Critical Period Causes Structural Changes in Myelinated Axons in the Adult Mouse Visual Pathway. Neurochem Res 2022; 47:2815-2825. [PMID: 35933550 DOI: 10.1007/s11064-022-03689-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 06/14/2022] [Accepted: 07/12/2022] [Indexed: 12/20/2022]
Abstract
An appropriate sensory experience during the early developmental period is important for brain maturation. Dark rearing during the visual critical period delays the maturation of neuronal circuits in the visual cortex. Although the formation and structural plasticity of the myelin sheaths on retinal ganglion cell axons modulate the visual function, the effects of dark rearing during the visual critical period on the structure of the retinal ganglion cell axons and their myelin sheaths are still unclear. To address this question, mice were reared in a dark box during the visual critical period and then normally reared to adulthood. We found that myelin sheaths on the retinal ganglion cell axons of dark-reared mice were thicker than those of normally reared mice in both the optic chiasm and optic nerve. Furthermore, whole-mount immunostaining with fluorescent axonal labeling and tissue clearing revealed that the myelin internodal length in dark-reared mice was shorter than that in normally reared mice in both the optic chiasm and optic nerve. These findings demonstrate that dark rearing during the visual critical period affects the morphology of myelin sheaths, shortens and thickens myelin sheaths in the visual pathway, despite the mice being reared in normal light/dark conditions after the dark rearing.
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Affiliation(s)
- Yasuyuki Osanai
- Division of Histology and Cell Biology, Department of Anatomy, School of Medicine, Jichi Medical University, Shimotsuke, Japan. .,Australian Regenerative Medicine Institute, Monash University, 15 Innovation Walk, Clayton, VIC, 3800, Australia.
| | - Batpurev Battulga
- Division of Histology and Cell Biology, Department of Anatomy, School of Medicine, Jichi Medical University, Shimotsuke, Japan
| | - Reiji Yamazaki
- Division of Histology and Cell Biology, Department of Anatomy, School of Medicine, Jichi Medical University, Shimotsuke, Japan
| | - Tom Kouki
- Division of Histology and Cell Biology, Department of Anatomy, School of Medicine, Jichi Medical University, Shimotsuke, Japan
| | - Megumi Yatabe
- Division of Histology and Cell Biology, Department of Anatomy, School of Medicine, Jichi Medical University, Shimotsuke, Japan
| | - Hiroaki Mizukami
- Division of Genetic Therapeutics, Center for Molecular Medicine, Jichi Medical University, Shimotsuke, Japan
| | - Kenta Kobayashi
- Section of Viral Vector Development, National Institute for Physiological Sciences, Okazaki, Japan.,SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Japan
| | - Yoshiaki Shinohara
- Division of Histology and Cell Biology, Department of Anatomy, School of Medicine, Jichi Medical University, Shimotsuke, Japan
| | - Yumiko Yoshimura
- SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Japan.,Division of Visual Information Processing, National Institute for Physiological Sciences, Okazaki, 444-8585, Japan
| | - Nobuhiko Ohno
- Division of Histology and Cell Biology, Department of Anatomy, School of Medicine, Jichi Medical University, Shimotsuke, Japan. .,Division of Ultrastructural Research, National Institute for Physiological Sciences, Okazaki, Japan.
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28
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Pantazopoulos H, Hossain NM, Chelini G, Durning P, Barbas H, Zikopoulos B, Berretta S. Chondroitin Sulphate Proteoglycan Axonal Coats in the Human Mediodorsal Thalamic Nucleus. Front Integr Neurosci 2022; 16:934764. [PMID: 35875507 PMCID: PMC9298528 DOI: 10.3389/fnint.2022.934764] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 06/21/2022] [Indexed: 12/21/2022] Open
Abstract
Mounting evidence supports a key involvement of the chondroitin sulfate proteoglycans (CSPGs) NG2 and brevican (BCAN) in the regulation of axonal functions, including axon guidance, fasciculation, conductance, and myelination. Prior work suggested the possibility that these functions may, at least in part, be carried out by specialized CSPG structures surrounding axons, termed axonal coats. However, their existence remains controversial. We tested the hypothesis that NG2 and BCAN, known to be associated with oligodendrocyte precursor cells, form axonal coats enveloping myelinated axons in the human brain. In tissue blocks containing the mediodorsal thalamic nucleus (MD) from healthy donors (n = 5), we used dual immunofluorescence, confocal microscopy, and unbiased stereology to characterize BCAN and NG2 immunoreactive (IR) axonal coats and measure the percentage of myelinated axons associated with them. In a subset of donors (n = 3), we used electron microscopy to analyze the spatial relationship between axons and NG2- and BCAN-IR axonal coats within the human MD. Our results show that a substantial percentage (∼64%) of large and medium myelinated axons in the human MD are surrounded by NG2- and BCAN-IR axonal coats. Electron microscopy studies show NG2- and BCAN-IR axonal coats are interleaved with myelin sheets, with larger axons displaying greater association with axonal coats. These findings represent the first characterization of NG2 and BCAN axonal coats in the human brain. The large percentage of axons surrounded by CSPG coats, and the role of CSPGs in axonal guidance, fasciculation, conductance, and myelination suggest that these structures may contribute to several key axonal properties.
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Affiliation(s)
- Harry Pantazopoulos
- Department of Psychiatry and Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS, United States
| | | | - Gabriele Chelini
- Translational Neuroscience Laboratory, Mclean Hospital, Belmont, MA, United States
- Department of Psychiatry, Harvard Medical School, Boston, MA, United States
| | - Peter Durning
- Translational Neuroscience Laboratory, Mclean Hospital, Belmont, MA, United States
| | - Helen Barbas
- Department of Health Sciences, Boston University, Boston, MA, United States
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, United States
- Neural Systems Laboratory, Boston University, Boston, MA, United States
| | - Basilis Zikopoulos
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, United States
- Neural Systems Laboratory, Boston University, Boston, MA, United States
| | - Sabina Berretta
- Translational Neuroscience Laboratory, Mclean Hospital, Belmont, MA, United States
- Department of Psychiatry, Harvard Medical School, Boston, MA, United States
- Program in Neuroscience, Harvard Medical School, Boston, MA, United States
- *Correspondence: Sabina Berretta,
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29
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Fan Z, Liang L, Ma R, Xie R, Zhao Y, Zhang M, Guo B, Zeng T, He D, Zhao X, Zhang H. Maternal sevoflurane exposure disrupts oligodendrocyte myelination of the postnatal hippocampus and induces cognitive and motor impairments in offspring. Biochem Biophys Res Commun 2022; 614:175-182. [DOI: 10.1016/j.bbrc.2022.05.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 05/11/2022] [Indexed: 11/02/2022]
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30
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Narine M, Colognato H. Current Insights Into Oligodendrocyte Metabolism and Its Power to Sculpt the Myelin Landscape. Front Cell Neurosci 2022; 16:892968. [PMID: 35573837 PMCID: PMC9097137 DOI: 10.3389/fncel.2022.892968] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 04/06/2022] [Indexed: 12/20/2022] Open
Abstract
Once believed to be part of the nervenkitt or “nerve glue” network in the central nervous system (CNS), oligodendroglial cells now have established roles in key neurological functions such as myelination, neuroprotection, and motor learning. More recently, oligodendroglia has become the subject of intense investigations aimed at understanding the contributions of its energetics to CNS physiology and pathology. In this review, we discuss the current understanding of oligodendroglial metabolism in regulating key stages of oligodendroglial development and health, its role in providing energy to neighboring cells such as neurons, as well as how alterations in oligodendroglial bioenergetics contribute to disease states. Importantly, we highlight how certain inputs can regulate oligodendroglial metabolism, including extrinsic and intrinsic mediators of cellular signaling, pharmacological compounds, and even dietary interventions. Lastly, we discuss emerging studies aimed at discovering the therapeutic potential of targeting components within oligodendroglial bioenergetic pathways.
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Affiliation(s)
- Mohanlall Narine
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY, United States
- Department of Neurobiology, & Behavior, Stony Brook University, Stony Brook, NY, United States
| | - Holly Colognato
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY, United States
- *Correspondence: Holly Colognato
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31
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Balraj A, Clarkson-Paredes C, Pajoohesh-Ganji A, Kay MW, Mendelowitz D, Miller RH. Refinement of axonal conduction and myelination in the mouse optic nerve indicate an extended period of postnatal developmental plasticity. Dev Neurobiol 2022; 82:308-325. [PMID: 35403346 PMCID: PMC9128412 DOI: 10.1002/dneu.22875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 02/18/2022] [Accepted: 03/17/2022] [Indexed: 11/07/2022]
Abstract
Retinal ganglion cells generate a pattern of action potentials to communicate visual information from the retina to cortical areas. Myelin, an insulating sheath, wraps axonal segments to facilitate signal propagation and when deficient, can impair visual function. Optic nerve development and initial myelination has largely been considered complete by the fifth postnatal week. However, the relationship between the extent of myelination and axonal signaling in the maturing optic nerve is not well characterized. Here, we examine the relationship between axon conduction and elements of myelination using extracellular nerve recordings, immunohistochemistry, western blot analysis, scanning electron microscopy, and simulations of nerve responses. Comparing compound action potentials from mice aged 4-12 weeks revealed five functional distinct axonal populations, an increase in the number of functional axons, and shifts toward fast-conducting axon populations at 5 and 8 weeks postnatal. At these ages, our analysis revealed increased myelin thickness, lower g-ratios and changes in the 14 kDa MBP isoform, while the density of axons and nodes of Ranvier remained constant. At 5 postnatal weeks, axon diameter increased, while at 8 weeks, increased expression of a mature sodium ion channel subtype, Nav 1.6, was observed at nodes of Ranvier. A simulation model of nerve conduction suggests that ion channel subtype, axon diameter, and myelin thickness are more likely to be key regulators of nerve function than g-ratio. Such refinement of axonal function and myelin rearrangement identified an extended period of maturation in the normal optic nerve that may facilitate the development of visual signaling patterns. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Annika Balraj
- Department of Anatomy, The George Washington University School of Medicine and Health Sciences, Washington, District of Columbia, USA
| | - Cheryl Clarkson-Paredes
- Nanofabrication and Imaging Center, The George Washington University School of Medicine and Health Sciences, Washington, District of Columbia, USA
| | - Ahdeah Pajoohesh-Ganji
- Department of Anatomy, The George Washington University School of Medicine and Health Sciences, Washington, District of Columbia, USA
| | - Matthew W. Kay
- Department of Biomedical Engineering, The George Washington University, Washington, District of Columbia, USA
| | - David Mendelowitz
- Department of Pharmacology and Physiology, The George Washington University School of Medicine and Health Sciences, Washington, District of Columbia, USA
| | - Robert H. Miller
- Department of Anatomy, The George Washington University School of Medicine and Health Sciences, Washington, District of Columbia, USA
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32
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Chen JF, Wang F, Huang NX, Xiao L, Mei F. Oligodendrocytes and Myelin: Active players in Neurodegenerative brains? Dev Neurobiol 2022; 82:160-174. [PMID: 35081276 DOI: 10.1002/dneu.22867] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 11/10/2022]
Abstract
Oligodendrocytes (OLs) are a major type of glial cells in the central nervous system that generate multiple myelin sheaths to wrap axons. Myelin ensures fast and efficient propagation of action potentials along axons and supports neurons with nourishment. The decay of OLs and myelin has been implicated in age-related neurodegenerative diseases and these changes are generally considered as an inevitable result of neuron loss and axon degeneration. Noticeably, OLs and myelin undergo dynamic changes in healthy adult brains, that is, newly formed OLs are continuously added throughout life from the differentiation of oligodendrocyte precursor cells (OPCs) and the pre-existing myelin sheaths may undergo degeneration or remodeling. Increasing evidence has shown that changes in OLs and myelin are present in the early stages of neurodegenerative diseases, and even prior to significant neuronal loss and functional deficits. More importantly, oligodendroglia-specific manipulation, by either deletion of the disease gene or enhancement of myelin renewal, can alleviate functional impairments in neurodegenerative animal models. These findings underscore the possibility that OLs and myelin are not passively but actively involved in neurodegenerative diseases and may play an important role in modulating neuronal function and survival. In this review, we summarize recent work characterizing OL and myelin changes in both healthy and neurodegenerative brains and discuss the potential of targeting oligodendroglial cells in treating neurodegenerative diseases. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Jing-Fei Chen
- Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Department of Histology and Embryology, Third Military Medical University, Chongqing, 400038, China
| | - Fei Wang
- Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Department of Histology and Embryology, Third Military Medical University, Chongqing, 400038, China
| | - Nan-Xing Huang
- Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Department of Histology and Embryology, Third Military Medical University, Chongqing, 400038, China
| | - Lan Xiao
- Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Department of Histology and Embryology, Third Military Medical University, Chongqing, 400038, China
| | - Feng Mei
- Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Department of Histology and Embryology, Third Military Medical University, Chongqing, 400038, China
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33
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Wiingaard Uldall S, Lundell H, Baaré WFC, Roman Siebner H, Rostrup E, Carlsson J. White matter diffusivity and its correlations to state measures of psychopathology in male refugees with posttraumatic stress disorder. Neuroimage Clin 2021; 33:102929. [PMID: 34998125 PMCID: PMC8741622 DOI: 10.1016/j.nicl.2021.102929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 09/29/2021] [Accepted: 10/20/2021] [Indexed: 12/03/2022]
Abstract
Post-traumatic stress disorder (PTSD) is a heterogenous condition and the underlying neurobiology is still poorly understood. In this study, we tested the hypothesis that PTSD is associated with microstructural changes in white matter (WM) fibre tracts that connect regions involved in emotional processing, memory, attention, and language. Furthermore, we examined how different response patterns to individualized trauma-provoking stimuli related to underlying WM microstructure. Sixty-nine trauma-affected male refugees with PTSD (N = 38) or without PTSD (N = 31) underwent clinical assessments and diffusion-weighted magnetic resonance imaging (DWI) of the whole brain at 3 Tesla. Diffusion tensor metrics were computed from DWI data and used to characterize regional white-matter microstructure. An automated tract segmentation method was used to extract diffusion tensor metrics from subject-based reconstructions of tract segments (ROI), including uncinate fasciculus (UF), cingulum bundle (CB), superior longitudinal fasciculus (SLF) in three subdivisions (SLF I - III), and fibre bundles connecting orbito-frontal cortex to striatum (OF-ST). Outside the scanner we obtained measures of immediate (state) arousal, avoidance and dissociation symptoms assessed in response to auditory exposure to a personal traumatic memory. Using mean FA of the middle part of each ROI, mixed ANOVA revealed a significant interaction between group, ROI and hemisphere. Post-hoc comparisons showed that, relative to refugees without PTSD, refugees with PTSD had lower FA in right CB, left SLF-I, bilateral OF-ST and bilateral SLF-II. Mean FA scaled negatively with avoidance in right CB while mean FA in bilateral UF scaled positively with individual scores reflecting dissociation symptoms. The results support a pathophysiological model of PTSD that implicates limbic structures, prefrontal cortex and striatum. The results also emphasize the need to consider PTSD's multifaceted manifestations when searching for functional-structural relationships.
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Affiliation(s)
- Sigurd Wiingaard Uldall
- Competence Centre for Transcultural Psychiatry (CTP), Mental Health Centre, Ballerup, Denmark; Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark.
| | - Henrik Lundell
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark
| | - William F C Baaré
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark
| | - Hartwig Roman Siebner
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark; Department for Neurology, Copenhagen University Hospital Bispebjerg, Copenhagen, Denmark; Institute of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Egill Rostrup
- Center for Neuropsychiatric Schizophrenia Research and Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research, Mental Health Centre, Glostrup, Copenhagen University Hospital, Denmark
| | - Jessica Carlsson
- Competence Centre for Transcultural Psychiatry (CTP), Mental Health Centre, Ballerup, Denmark; Center for Neuropsychiatric Schizophrenia Research and Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research, Mental Health Centre, Glostrup, Copenhagen University Hospital, Denmark
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34
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Faw TD, Lakhani B, Schmalbrock P, Knopp MV, Lohse KR, Kramer JLK, Liu H, Nguyen HT, Phillips EG, Bratasz A, Fisher LC, Deibert RJ, Boyd LA, McTigue DM, Basso DM. Eccentric rehabilitation induces white matter plasticity and sensorimotor recovery in chronic spinal cord injury. Exp Neurol 2021; 346:113853. [PMID: 34464653 PMCID: PMC10084731 DOI: 10.1016/j.expneurol.2021.113853] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 08/04/2021] [Accepted: 08/26/2021] [Indexed: 12/12/2022]
Abstract
Experience-dependent white matter plasticity offers new potential for rehabilitation-induced recovery after neurotrauma. This first-in-human translational experiment combined myelin water imaging in humans and genetic fate-mapping of oligodendrocyte lineage cells in mice to investigate whether downhill locomotor rehabilitation that emphasizes eccentric muscle actions promotes white matter plasticity and recovery in chronic, incomplete spinal cord injury (SCI). In humans, of 20 individuals with SCI that enrolled, four passed the imaging screen and had myelin water imaging before and after a 12-week (3 times/week) downhill locomotor treadmill training program (SCI + DH). One individual was excluded for imaging artifacts. Uninjured control participants (n = 7) had two myelin water imaging sessions within the same day. Changes in myelin water fraction (MWF), a histopathologically-validated myelin biomarker, were analyzed in a priori motor learning and non-motor learning brain regions and the cervical spinal cord using statistical approaches appropriate for small sample sizes. PDGFRα-CreERT2:mT/mG mice, that express green fluorescent protein on oligodendrocyte precursor cells and subsequent newly-differentiated oligodendrocytes upon tamoxifen-induced recombination, were either naive (n = 6) or received a moderate (75 kilodyne), contusive SCI at T9 and were randomized to downhill training (n = 6) or unexercised groups (n = 6). We initiated recombination 29 days post-injury, seven days prior to downhill training. Mice underwent two weeks of daily downhill training on the same 10% decline grade used in humans. Between-group comparison of functional (motor and sensory) and histological (oligodendrogenesis, oligodendroglial/axon interaction, paranodal structure) outcomes occurred post-training. In humans with SCI, downhill training increased MWF in brain motor learning regions (postcentral, precuneus) and mixed motor and sensory tracts of the ventral cervical spinal cord compared to control participants (P < 0.05). In mice with thoracic SCI, downhill training induced oligodendrogenesis in cervical dorsal and lateral white matter, increased axon-oligodendroglial interactions, and normalized paranodal structure in dorsal column sensory tracts (P < 0.05). Downhill training improved sensorimotor recovery in mice by normalizing hip and knee motor control and reducing hyperalgesia, both of which were associated with new oligodendrocytes in the cervical dorsal columns (P < 0.05). Our findings indicate that eccentric-focused, downhill rehabilitation promotes white matter plasticity and improved function in chronic SCI, likely via oligodendrogenesis in nervous system regions activated by the training paradigm. Together, these data reveal an exciting role for eccentric training in white matter plasticity and sensorimotor recovery after SCI.
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Affiliation(s)
- Timothy D Faw
- Neuroscience Graduate Program, The Ohio State University, Columbus, OH 43210, USA; Center for Brain and Spinal Cord Repair, The Ohio State University, Columbus, OH 43210, USA; Department of Orthopaedic Surgery, Duke University, Durham, NC 27710, USA
| | - Bimal Lakhani
- Department of Physical Therapy, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Petra Schmalbrock
- Department of Radiology, The Ohio State University, Columbus, OH 43210, USA
| | - Michael V Knopp
- Department of Radiology, The Ohio State University, Columbus, OH 43210, USA
| | - Keith R Lohse
- Department of Health, Kinesiology, and Recreation, University of Utah, Salt Lake City, UT 84112, USA; Department of Physical Therapy and Athletic Training, University of Utah, Salt Lake City, UT 84108, USA
| | - John L K Kramer
- Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, BC V6T 1Z3, Canada; International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
| | - Hanwen Liu
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC V5Z 1M9, Canada; Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Huyen T Nguyen
- Department of Radiology, The Ohio State University, Columbus, OH 43210, USA
| | - Eileen G Phillips
- Center for Brain and Spinal Cord Repair, The Ohio State University, Columbus, OH 43210, USA; School of Health and Rehabilitation Sciences, The Ohio State University, Columbus, OH 43210, USA
| | - Anna Bratasz
- Small Animal Imaging Shared Resources, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Lesley C Fisher
- Center for Brain and Spinal Cord Repair, The Ohio State University, Columbus, OH 43210, USA; School of Health and Rehabilitation Sciences, The Ohio State University, Columbus, OH 43210, USA
| | - Rochelle J Deibert
- Center for Brain and Spinal Cord Repair, The Ohio State University, Columbus, OH 43210, USA; School of Health and Rehabilitation Sciences, The Ohio State University, Columbus, OH 43210, USA
| | - Lara A Boyd
- Department of Physical Therapy, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Dana M McTigue
- Neuroscience Graduate Program, The Ohio State University, Columbus, OH 43210, USA; Center for Brain and Spinal Cord Repair, The Ohio State University, Columbus, OH 43210, USA; Department of Neuroscience, The Ohio State University, Columbus, OH 43210, USA
| | - D Michele Basso
- Neuroscience Graduate Program, The Ohio State University, Columbus, OH 43210, USA; Center for Brain and Spinal Cord Repair, The Ohio State University, Columbus, OH 43210, USA; School of Health and Rehabilitation Sciences, The Ohio State University, Columbus, OH 43210, USA.
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35
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Heflin JK, Sun W. Novel Toolboxes for the Investigation of Activity-Dependent Myelination in the Central Nervous System. Front Cell Neurosci 2021; 15:769809. [PMID: 34795563 PMCID: PMC8592894 DOI: 10.3389/fncel.2021.769809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 10/06/2021] [Indexed: 11/13/2022] Open
Abstract
Myelination is essential for signal processing within neural networks. Emerging data suggest that neuronal activity positively instructs myelin development and myelin adaptation during adulthood. However, the underlying mechanisms controlling activity-dependent myelination have not been fully elucidated. Myelination is a multi-step process that involves the proliferation and differentiation of oligodendrocyte precursor cells followed by the initial contact and ensheathment of axons by mature oligodendrocytes. Conventional end-point studies rarely capture the dynamic interaction between neurons and oligodendrocyte lineage cells spanning such a long temporal window. Given that such interactions and downstream signaling cascades are likely to occur within fine cellular processes of oligodendrocytes and their precursor cells, overcoming spatial resolution limitations represents another technical hurdle in the field. In this mini-review, we discuss how advanced genetic, cutting-edge imaging, and electrophysiological approaches enable us to investigate neuron-oligodendrocyte lineage cell interaction and myelination with both temporal and spatial precision.
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Affiliation(s)
- Jack Kent Heflin
- Department of Neuroscience, Wexner Medical Center, The Ohio State University, Columbus, OH, United States
| | - Wenjing Sun
- Department of Neuroscience, Wexner Medical Center, The Ohio State University, Columbus, OH, United States
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36
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Experience-dependent myelination following stress is mediated by the neuropeptide dynorphin. Neuron 2021; 109:3619-3632.e5. [PMID: 34536353 DOI: 10.1016/j.neuron.2021.08.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 07/14/2021] [Accepted: 08/13/2021] [Indexed: 11/22/2022]
Abstract
Emerging evidence implicates experience-dependent myelination in learning and memory. However, the specific signals underlying this process remain unresolved. We demonstrate that the neuropeptide dynorphin, which is released from neurons upon high levels of activity, promotes experience-dependent myelination. Following forced swim stress, an experience that induces striatal dynorphin release, we observe increased striatal oligodendrocyte precursor cell (OPC) differentiation and myelination, which is abolished by deleting dynorphin or blocking its endogenous receptor, kappa opioid receptor (KOR). We find that dynorphin also promotes developmental OPC differentiation and myelination and demonstrate that this effect requires KOR expression specifically in OPCs. We characterize dynorphin-expressing neurons and use genetic sparse labeling to trace their axonal projections. Surprisingly, we find that they are unmyelinated normally and following forced swim stress. We propose a new model whereby experience-dependent and developmental myelination is mediated by unmyelinated, neuropeptide-expressing neurons that promote OPC differentiation for the myelination of neighboring axons.
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37
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Periods of synchronized myelin changes shape brain function and plasticity. Nat Neurosci 2021; 24:1508-1521. [PMID: 34711959 DOI: 10.1038/s41593-021-00917-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 07/30/2021] [Indexed: 12/11/2022]
Abstract
Myelin, a lipid membrane that wraps axons, enabling fast neurotransmission and metabolic support to axons, is conventionally thought of as a static structure that is set early in development. However, recent evidence indicates that in the central nervous system (CNS), myelination is a protracted and plastic process, ongoing throughout adulthood. Importantly, myelin is emerging as a potential modulator of neuronal networks, and evidence from human studies has highlighted myelin as a major player in shaping human behavior and learning. Here we review how myelin changes throughout life and with learning. We discuss potential mechanisms of myelination at different life stages, explore whether myelin plasticity provides the regenerative potential of the CNS white matter, and question whether changes in myelin may underlie neurological disorders.
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38
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Chorghay Z, MacFarquhar D, Li VJ, Aufmkolk S, Schohl A, Wiseman PW, Káradóttir RT, Ruthazer ES. Activity-dependent alteration of early myelin ensheathment in a developing sensory circuit. J Comp Neurol 2021; 530:871-885. [PMID: 34599848 DOI: 10.1002/cne.25253] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/26/2021] [Accepted: 09/28/2021] [Indexed: 12/23/2022]
Abstract
Myelination allows for the regulation of conduction velocity, affecting the precise timing of neuronal inputs important for the development and function of brain circuits. In turn, myelination may be altered by changes in experience, neuronal activity, and vesicular release, but the links between sensory experience, corresponding neuronal activity, and resulting alterations in myelination require further investigation. We thus studied the development of myelination in the Xenopus laevis tadpole, a classic model for studies of visual system development and function because it is translucent and visually responsive throughout the formation of its retinotectal system. We begin with a systematic characterization of the timecourse of early myelin ensheathment in the Xenopus retinotectal system using immunohistochemistry of myelin basic protein (MBP) along with third harmonic generation (THG) microscopy, a label-free structural imaging technique. Based on the mid-larval developmental progression of MBP expression in Xenopus, we identified an appropriate developmental window in which to assess the effects of early temporally patterned visual experience on myelin ensheathment. We used calcium imaging of axon terminals in vivo to characterize the responses of retinal ganglion cells over a range of stroboscopic stimulation frequencies. Strobe frequencies that reliably elicited robust versus dampened calcium responses were then presented to animals for 7 d, and differences in the amount of early myelin ensheathment at the optic chiasm were subsequently quantified. This study provides evidence that it is not just the presence but also to the specific temporal properties of sensory stimuli that are important for myelin plasticity.
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Affiliation(s)
- Zahraa Chorghay
- Montreal Neurological Institute-Hospital and Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
| | - David MacFarquhar
- Department of Chemistry, Otto Maass Building, McGill University, Montréal, QC, Canada.,Department of Physics, Otto Maass Building, McGill University, Montréal, QC, Canada
| | - Vanessa J Li
- Montreal Neurological Institute-Hospital and Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
| | - Sarah Aufmkolk
- Montreal Neurological Institute-Hospital and Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada.,Department of Chemistry, Otto Maass Building, McGill University, Montréal, QC, Canada.,Department of Physics, Otto Maass Building, McGill University, Montréal, QC, Canada
| | - Anne Schohl
- Montreal Neurological Institute-Hospital and Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
| | - Paul W Wiseman
- Department of Chemistry, Otto Maass Building, McGill University, Montréal, QC, Canada.,Department of Physics, Otto Maass Building, McGill University, Montréal, QC, Canada
| | - Ragnhildur Thóra Káradóttir
- Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute and Department of Veterinary Medicine, University of Cambridge, Cambridge, UK.,Department of Physiology, BioMedical Center, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | - Edward S Ruthazer
- Montreal Neurological Institute-Hospital and Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
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Chen L, Ren SY, Li RX, Liu K, Chen JF, Yang YJ, Deng YB, Wang HZ, Xiao L, Mei F, Wang F. Chronic Exposure to Hypoxia Inhibits Myelinogenesis and Causes Motor Coordination Deficits in Adult Mice. Neurosci Bull 2021; 37:1397-1411. [PMID: 34292513 PMCID: PMC8490606 DOI: 10.1007/s12264-021-00745-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 03/06/2021] [Indexed: 12/18/2022] Open
Abstract
Exposure to chronic hypoxia is considered to be a risk factor for deficits in brain function in adults, but the underlying mechanisms remain largely unknown. Since active myelinogenesis persists in the adult central nervous system, here we aimed to investigate the impact of chronic hypoxia on myelination and the related functional consequences in adult mice. Using a transgenic approach to label newly-generated myelin sheaths (NG2-CreERTM; Tau-mGFP), we found that myelinogenesis was highly active in most brain regions, such as the motor cortex and corpus callosum. After exposure to hypoxia (10% oxygen) 12 h per day for 4 weeks, myelinogenesis was largely inhibited in the 4-month old brain and the mice displayed motor coordination deficits revealed by the beam-walking test. To determine the relationship between the inhibited myelination and functional impairment, we induced oligodendroglia-specific deletion of the transcription factor Olig2 by tamoxifen (NG2-CreERTM; Tau-mGFP; Olig2 fl/fl) in adult mice to mimic the decreased myelinogenesis caused by hypoxia. The deletion of Olig2 inhibited myelinogenesis and consequently impaired motor coordination, suggesting that myelinogenesis is required for motor function in adult mice. To understand whether enhancing myelination could protect brain functions against hypoxia, we treated hypoxic mice with the myelination-enhancing drug-clemastine, which resulted in enhanced myelogenesis and improved motor coordination. Taken together, our data indicate that chronic hypoxia inhibits myelinogenesis and causes functional deficits in the brain and that enhancing myelinogenesis protects brain functions against hypoxia-related deficits.
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Affiliation(s)
- Lin Chen
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Third Military Medical University, Chongqing, 400038, China
| | - Shu-Yu Ren
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Third Military Medical University, Chongqing, 400038, China
| | - Rui-Xue Li
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Third Military Medical University, Chongqing, 400038, China
| | - Kun Liu
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Third Military Medical University, Chongqing, 400038, China
| | - Jing-Fei Chen
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Third Military Medical University, Chongqing, 400038, China
| | - Yu-Jian Yang
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Third Military Medical University, Chongqing, 400038, China
| | - Yong-Bin Deng
- Department of Neurosurgery, Chongqing Emergency Medical Center, Chongqing University, Chongqing, 400014, China
| | - Han-Zhi Wang
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Third Military Medical University, Chongqing, 400038, China
| | - Lan Xiao
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Third Military Medical University, Chongqing, 400038, China
| | - Feng Mei
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Third Military Medical University, Chongqing, 400038, China.
| | - Fei Wang
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Brain and Intelligence Research Key Laboratory of Chongqing Education Commission, Third Military Medical University, Chongqing, 400038, China.
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40
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Turan F, Yilmaz Ö, Schünemann L, Lindenberg TT, Kalanithy JC, Harder A, Ahmadi S, Duman T, MacDonald RB, Winter D, Liu C, Odermatt B. Effect of modulating glutamate signaling on myelinating oligodendrocytes and their development-A study in the zebrafish model. J Neurosci Res 2021; 99:2774-2792. [PMID: 34520578 DOI: 10.1002/jnr.24940] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 07/12/2021] [Accepted: 07/21/2021] [Indexed: 01/02/2023]
Abstract
Myelination is crucial for the development and maintenance of axonal integrity, especially fast axonal action potential conduction. There is increasing evidence that glutamate signaling and release through neuronal activity modulates the myelination process. In this study, we examine the effect of manipulating glutamate signaling on myelination of oligodendrocyte (OL) lineage cells and their development in zebrafish (zf). We use the "intensity-based glutamate-sensing fluorescent reporter" (iGluSnFR) in the zf model (both sexes) to address the hypothesis that glutamate is implicated in regulation of myelinating OLs. Our results show that glial iGluSnFR expression significantly reduces OL lineage cell number and the expression of myelin markers in larvae (zfl) and adult brains. The specific glutamate receptor agonist, L-AP4, rescues this iGluSnFR effect by significantly increasing the expression of the myelin-related genes, plp1b and mbpa, and enhances myelination in L-AP4-injected zfl compared to controls. Furthermore, we demonstrate that degrading glutamate using Glutamat-Pyruvate Transaminase (GPT) or the blockade of glutamate reuptake by L-trans-pyrrolidine-2,4-dicarboxylate (PDC) significantly decreases myelin-related genes and drastically declines myelination in brain ventricle-injected zfl. Moreover, we found that myelin-specific ClaudinK (CldnK) and 36K protein expression is significantly decreased in iGluSnFR-expressing zfl and adult brains compared to controls. Taken together, this study confirms that glutamate signaling is directly required for the preservation of myelinating OLs and for the myelination process itself. These findings further suggest that glutamate signaling may provide novel targets to therapeutically boost remyelination in several demyelinating diseases of the CNS.
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Affiliation(s)
- Funda Turan
- Medical Faculty, Institute of Neuroanatomy, University of Bonn, Bonn, Germany.,Faculty of Science, Biology Department, Ankara University, Ankara, Turkey
| | - Öznur Yilmaz
- Medical Faculty, Institute of Anatomy and Cell-Biology, University of Bonn, Bonn, Germany
| | - Lena Schünemann
- Medical Faculty, Institute of Anatomy and Cell-Biology, University of Bonn, Bonn, Germany
| | - Tobias T Lindenberg
- Medical Faculty, Institute of Neuroanatomy, University of Bonn, Bonn, Germany
| | - Jeshurun C Kalanithy
- Medical Faculty, Institute of Anatomy and Cell-Biology, University of Bonn, Bonn, Germany
| | - Alexander Harder
- Institute of Physical and Theoretical Chemistry, University of Bonn, Bonn, Germany
| | - Shiva Ahmadi
- Medical Faculty, Institute for Biochemistry and Molecular Biology (IBMB), University of Bonn, Bonn, Germany
| | - Türker Duman
- Faculty of Science, Biology Department, Ankara University, Ankara, Turkey
| | - Ryan B MacDonald
- Institute of Ophthalmology, University College London, London, UK
| | - Dominic Winter
- Medical Faculty, Institute for Biochemistry and Molecular Biology (IBMB), University of Bonn, Bonn, Germany
| | - Changsheng Liu
- Medical Faculty, Institute of Anatomy and Cell-Biology, University of Bonn, Bonn, Germany
| | - Benjamin Odermatt
- Medical Faculty, Institute of Neuroanatomy, University of Bonn, Bonn, Germany.,Medical Faculty, Institute of Anatomy and Cell-Biology, University of Bonn, Bonn, Germany
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41
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Almeida RG, Williamson JM, Madden ME, Early JJ, Voas MG, Talbot WS, Bianco IH, Lyons DA. Myelination induces axonal hotspots of synaptic vesicle fusion that promote sheath growth. Curr Biol 2021; 31:3743-3754.e5. [PMID: 34270947 PMCID: PMC8445327 DOI: 10.1016/j.cub.2021.06.036] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 05/17/2021] [Accepted: 06/11/2021] [Indexed: 02/08/2023]
Abstract
Myelination of axons by oligodendrocytes enables fast saltatory conduction. Oligodendrocytes are responsive to neuronal activity, which has been shown to induce changes to myelin sheaths, potentially to optimize conduction and neural circuit function. However, the cellular bases of activity-regulated myelination in vivo are unclear, partly due to the difficulty of analyzing individual myelinated axons over time. Activity-regulated myelination occurs in specific neuronal subtypes and can be mediated by synaptic vesicle fusion, but several questions remain: it is unclear whether vesicular fusion occurs stochastically along axons or in discrete hotspots during myelination and whether vesicular fusion regulates myelin targeting, formation, and/or growth. It is also unclear why some neurons, but not others, exhibit activity-regulated myelination. Here, we imaged synaptic vesicle fusion in individual neurons in living zebrafish and documented robust vesicular fusion along axons during myelination. Surprisingly, we found that axonal vesicular fusion increased upon and required myelination. We found that axonal vesicular fusion was enriched in hotspots, namely the heminodal non-myelinated domains into which sheaths grew. Blocking vesicular fusion reduced the stable formation and growth of myelin sheaths, and chemogenetically stimulating neuronal activity promoted sheath growth. Finally, we observed high levels of axonal vesicular fusion only in neuronal subtypes that exhibit activity-regulated myelination. Our results identify a novel "feedforward" mechanism whereby the process of myelination promotes the neuronal activity-regulated signal, vesicular fusion that, in turn, consolidates sheath growth along specific axons selected for myelination.
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Affiliation(s)
- Rafael G Almeida
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.
| | - Jill M Williamson
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Megan E Madden
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Jason J Early
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Matthew G Voas
- Department of Developmental Biology, Stanford University, Stanford, CA, USA; National Cancer Institute, Frederick, MD, USA
| | - William S Talbot
- Department of Developmental Biology, Stanford University, Stanford, CA, USA
| | - Isaac H Bianco
- Department of Neuroscience, Physiology and Pharmacology, UCL, London, UK
| | - David A Lyons
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.
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42
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Rupnik M, Baker D, Selwood DL. Oligodendrocytes, BK channels and remyelination. F1000Res 2021; 10:781. [PMID: 34909188 PMCID: PMC8596180 DOI: 10.12688/f1000research.53422.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/28/2021] [Indexed: 11/09/2023] Open
Abstract
Oligodendrocytes wrap multiple lamellae of their membrane, myelin, around axons of the central nervous system (CNS), to improve impulse conduction. Myelin synthesis is specialised and dynamic, responsive to local neuronal excitation. Subtle pathological insults are sufficient to cause significant neuronal metabolic impairment, so myelin preservation is necessary to safeguard neural networks. Multiple sclerosis (MS) is the most prevalent demyelinating disease of the CNS. In MS, inflammatory attacks against myelin, proposed to be autoimmune, cause myelin decay and oligodendrocyte loss, leaving neurons vulnerable. Current therapies target the prominent neuroinflammation but are mostly ineffective in protecting from neurodegeneration and the progressive neurological disability. People with MS have substantially higher levels of extracellular glutamate, the main excitatory neurotransmitter. This impairs cellular homeostasis to cause excitotoxic stress. Large conductance Ca2 +-activated K + channels (BK channels) could preserve myelin or allow its recovery by protecting cells from the resulting excessive excitability. This review evaluates the role of excitotoxic stress, myelination and BK channels in MS pathology, and explores the hypothesis that BK channel activation could be a therapeutic strategy to protect oligodendrocytes from excitotoxic stress in MS. This could reduce progression of neurological disability if used in parallel to immunomodulatory therapies.
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Affiliation(s)
- Maddalena Rupnik
- Wolfson Insitute for Biomedical Research, University College London, London, WC1E 6BT, UK
| | - David Baker
- Centre for Neuroscience and Trauma, Blizard Institute, Queen Mary University of London, London, WC1E 6BT, UK
| | - David L. Selwood
- Wolfson Insitute for Biomedical Research, University College London, London, WC1E 6BT, UK
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43
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Rupnik M, Baker D, Selwood DL. Oligodendrocytes, BK channels and the preservation of myelin. F1000Res 2021; 10:781. [PMID: 34909188 PMCID: PMC8596180 DOI: 10.12688/f1000research.53422.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/02/2021] [Indexed: 11/20/2022] Open
Abstract
Oligodendrocytes wrap multiple lamellae of their membrane, myelin, around axons of the central nervous system (CNS), to improve impulse conduction. Myelin synthesis is specialised and dynamic, responsive to local neuronal excitation. Subtle pathological insults are sufficient to cause significant neuronal metabolic impairment, so myelin preservation is necessary to safeguard neural networks. Multiple sclerosis (MS) is the most prevalent demyelinating disease of the CNS. In MS, inflammatory attacks against myelin, proposed to be autoimmune, cause myelin decay and oligodendrocyte loss, leaving neurons vulnerable. Current therapies target the prominent neuroinflammation but are mostly ineffective in protecting from neurodegeneration and the progressive neurological disability. People with MS have substantially higher levels of extracellular glutamate, the main excitatory neurotransmitter. This impairs cellular homeostasis to cause excitotoxic stress. Large conductance Ca2 +-activated K + channels (BK channels) could preserve myelin or allow its recovery by protecting cells from the resulting excessive excitability. This review evaluates the role of excitotoxic stress, myelination and BK channels in MS pathology, and explores the hypothesis that BK channel activation could be a therapeutic strategy to protect oligodendrocytes from excitotoxic stress in MS. This could reduce progression of neurological disability if used in parallel to immunomodulatory therapies.
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Affiliation(s)
- Maddalena Rupnik
- Wolfson Insitute for Biomedical Research, University College London, London, WC1E 6BT, UK
| | - David Baker
- Centre for Neuroscience and Trauma, Blizard Institute, Queen Mary University of London, London, WC1E 6BT, UK
| | - David L. Selwood
- Wolfson Insitute for Biomedical Research, University College London, London, WC1E 6BT, UK
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44
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Monje M, Káradóttir RT. The bright and the dark side of myelin plasticity: Neuron-glial interactions in health and disease. Semin Cell Dev Biol 2021; 116:10-15. [PMID: 33293232 PMCID: PMC8178421 DOI: 10.1016/j.semcdb.2020.11.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 11/24/2020] [Accepted: 11/26/2020] [Indexed: 12/16/2022]
Abstract
Neuron-glial interactions shape neural circuit establishment, refinement and function. One of the key neuron-glial interactions takes place between axons and oligodendroglial precursor cells. Interactions between neurons and oligodendrocyte precursor cells (OPCs) promote OPC proliferation, generation of new oligodendrocytes and myelination, shaping myelin development and ongoing adaptive myelin plasticity in the brain. Communication between neurons and OPCs can be broadly divided into paracrine and synaptic mechanisms. Following the Nobel mini-symposium "The Dark Side of the Brain" in late 2019 at the Karolinska Institutet, this mini-review will focus on the bright and dark sides of neuron-glial interactions and discuss paracrine and synaptic interactions between neurons and OPCs and their malignant counterparts.
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Affiliation(s)
- Michelle Monje
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA.
| | - Ragnhildur Thóra Káradóttir
- Wellcome - Medical Research Council Cambridge Stem Cell Institute & Department of Veterinary Medicine, University of Cambridge, Cambridge, UK; Department of Physiology, BioMedical Center, Faculty of Medicine, University of Iceland, Reykjavik, Iceland.
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45
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Simankova A, Bizen N, Saitoh S, Shibata S, Ohno N, Abe M, Sakimura K, Takebayashi H. Ddx20, DEAD box helicase 20, is essential for the differentiation of oligodendrocyte and maintenance of myelin gene expression. Glia 2021; 69:2559-2574. [PMID: 34231259 DOI: 10.1002/glia.24058] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 12/17/2022]
Abstract
Oligodendrocytes form myelin sheaths that surround axons, contributing to saltatory conduction and proper central nervous system (CNS) function. Oligodendrocyte progenitor cells (OPCs) are generated during the embryonic stage and differentiate into myelinating oligodendrocytes postnatally. Ddx20 is a multifunctional, DEAD-box helicase involved in multiple cellular processes, including transcription, splicing, microRNA biogenesis, and translation. Although defects in each of these processes result in abnormal oligodendrocyte differentiation and myelination, the involvement of Ddx20 in oligodendrocyte terminal differentiation remains unknown. To address this question, we used Mbp-Cre mice to generate Ddx20 conditional knockout (cKO) mice to allow for the deletion of Ddx20 from mature oligodendrocytes. Mbp-Cre;Ddx20 cKO mice demonstrated small body sizes, behavioral abnormalities, muscle weakness, and short lifespans, with mortality by the age of 2 months old. Histological analyses demonstrated significant reductions in the number of mature oligodendrocytes and drastic reductions in the expression levels of myelin-associated mRNAs, such as Mbp and Plp at postnatal day 42. The number of OPCs did not change. A thin myelin layer was observed for large-diameter axons in Ddx20 cKO mice, based on electron microscopic analysis. A bromodeoxyuridine (BrdU) labeling experiment demonstrated that terminal differentiation was perturbed from ages 2 weeks to 7 weeks in the CNS of Mbp-Cre;Ddx20 cKO mice. The activation of mitogen-activated protein (MAP) kinase, which promotes myelination, was downregulated in the Ddx20 cKO mice based on immunohistochemical detection. These results indicate that Ddx20 is an essential factor for terminal differentiation of oligodendrocytes and maintenance of myelin gene expression.
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Affiliation(s)
- Anna Simankova
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Norihisa Bizen
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Sei Saitoh
- Section of Electron Microscopy, Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Japan.,Department of Biomedical Molecular Sciences (Anatomy II), Fujita Health University School of Medicine, Toyoake, Japan
| | - Shinsuke Shibata
- Division of Microscopic Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Nobuhiko Ohno
- Department of Anatomy, Division of Histology and Cell Biology, School of Medicine, Jichi Medical University, Shimotsuke, Japan.,Division of Ultrastructural Research, National Institute for Physiological Sciences, Okazaki, Japan
| | - Manabu Abe
- Department of Animal Model Development, Brain Research Institute, Niigata University, Niigata, Japan
| | - Kenji Sakimura
- Department of Animal Model Development, Brain Research Institute, Niigata University, Niigata, Japan
| | - Hirohide Takebayashi
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan.,Center for Coordination of Research Facilities, Niigata University, Niigata, Japan
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46
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Guehl NJ, Ramos-Torres KM, Linnman C, Moon SH, Dhaynaut M, Wilks MQ, Han PK, Ma C, Neelamegam R, Zhou YP, Popko B, Correia JA, Reich DS, Fakhri GE, Herscovitch P, Normandin MD, Brugarolas P. Evaluation of the potassium channel tracer [ 18F]3F4AP in rhesus macaques. J Cereb Blood Flow Metab 2021; 41:1721-1733. [PMID: 33090071 PMCID: PMC8221756 DOI: 10.1177/0271678x20963404] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Demyelination causes slowed or failed neuronal conduction and is a driver of disability in multiple sclerosis and other neurological diseases. Currently, the gold standard for imaging demyelination is MRI, but despite its high spatial resolution and sensitivity to demyelinated lesions, it remains challenging to obtain specific and quantitative measures of molecular changes involved in demyelination. To understand the contribution of demyelination in different diseases and to assess the efficacy of myelin-repair therapies, it is critical to develop new in vivo imaging tools sensitive to changes induced by demyelination. Upon demyelination, axonal K+ channels, normally located underneath the myelin sheath, become exposed and increase in expression, causing impaired conduction. Here, we investigate the properties of the K+ channel PET tracer [18F]3F4AP in primates and its sensitivity to a focal brain injury that occurred three years prior to imaging. [18F]3F4AP exhibited favorable properties for brain imaging including high brain penetration, high metabolic stability, high plasma availability, high reproducibility, high specificity, and fast kinetics. [18F]3F4AP showed preferential binding in areas of low myelin content as well as in the previously injured area. Sensitivity of [18F]3F4AP for the focal brain injury was higher than [18F]FDG, [11C]PiB, and [11C]PBR28, and compared favorably to currently used MRI methods.
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Affiliation(s)
- Nicolas J Guehl
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Karla M Ramos-Torres
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Clas Linnman
- Spaulding Neuroimaging Lab, Spaulding Rehabilitation Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Sung-Hyun Moon
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Maeva Dhaynaut
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Moses Q Wilks
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Paul K Han
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Chao Ma
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Ramesh Neelamegam
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Yu-Peng Zhou
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Brian Popko
- Department of Neurology, Northwestern Feinberg School of Medicine, Chicago, IL, USA
| | - John A Correia
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Daniel S Reich
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Georges El Fakhri
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Peter Herscovitch
- Positron Emission Tomography Department, NIH Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Marc D Normandin
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Pedro Brugarolas
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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47
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Sancho L, Contreras M, Allen NJ. Glia as sculptors of synaptic plasticity. Neurosci Res 2021; 167:17-29. [PMID: 33316304 PMCID: PMC8513541 DOI: 10.1016/j.neures.2020.11.005] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 11/05/2020] [Accepted: 11/09/2020] [Indexed: 12/16/2022]
Abstract
Glial cells are non-neuronal cells in the nervous system that are crucial for proper brain development and function. Three major classes of glia in the central nervous system (CNS) include astrocytes, microglia and oligodendrocytes. These cells have dynamic morphological and functional properties and constantly surveil neural activity throughout life, sculpting synaptic plasticity. Astrocytes form part of the tripartite synapse with neurons and perform many homeostatic functions essential to proper synaptic function including clearing neurotransmitter and regulating ion balance; they can modify these properties, in addition to additional mechanisms such as gliotransmitter release, to influence short- and long-term plasticity. Microglia, the resident macrophage of the CNS, monitor synaptic activity and can eliminate synapses by phagocytosis or modify synapses by release of cytokines or neurotrophic factors. Oligodendrocytes regulate speed of action potential conduction and efficiency of information exchange through the formation of myelin, having important consequences for the plasticity of neural circuits. A deeper understanding of how glia modulate synaptic and circuit plasticity will further our understanding of the ongoing changes that take place throughout life in the dynamic environment of the CNS.
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Affiliation(s)
- Laura Sancho
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Minerva Contreras
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Nicola J Allen
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Rd, La Jolla, CA, 92037, USA.
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48
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Nemes-Baran AD, White DR, DeSilva TM. Fractalkine-Dependent Microglial Pruning of Viable Oligodendrocyte Progenitor Cells Regulates Myelination. Cell Rep 2021; 32:108047. [PMID: 32814050 PMCID: PMC7478853 DOI: 10.1016/j.celrep.2020.108047] [Citation(s) in RCA: 86] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/22/2020] [Accepted: 07/28/2020] [Indexed: 12/14/2022] Open
Abstract
Oligodendrogenesis occurs during early postnatal development, coincident with neurogenesis and synaptogenesis, raising the possibility that microglia-dependent pruning mechanisms that modulate neurons regulate myelin sheath formation. Here we show a population of ameboid microglia migrating from the ventricular zone into the corpus callosum during early postnatal development, termed “the fountain of microglia,” phagocytosing viable oligodendrocyte progenitor cells (OPCs) before onset of myelination. Fractalkine receptor-deficient mice exhibit a reduction in microglial engulfment of viable OPCs, increased numbers of oligodendrocytes, and reduced myelin thickness but no change in axon number. These data provide evidence that microglia phagocytose OPCs as a homeostatic mechanism for proper myelination. A hallmark of hypomyelinating developmental disorders such as periventricular leukomalacia and of adult demyelinating diseases such as multiple sclerosis is increased numbers of oligodendrocytes but failure to myelinate, suggesting that microglial pruning of OPCs may be impaired in pathological states and hinder myelination. Nemes-Baran et al. show that ameboid microglia engulf living oligodendrocyte progenitor cells (OPCs) during brain development. Fractalkine receptor-deficient microglia exhibit a reduction in engulfment of OPCs, resulting in a surplus of oligodendrocytes and impaired myelination. These data provide evidence that microglia phagocytose OPCs as a homeostatic mechanism required for normal myelination.
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Affiliation(s)
- Ashley D Nemes-Baran
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Donovan R White
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Tara M DeSilva
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA.
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49
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Hughes AN. Glial Cells Promote Myelin Formation and Elimination. Front Cell Dev Biol 2021; 9:661486. [PMID: 34046407 PMCID: PMC8144722 DOI: 10.3389/fcell.2021.661486] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 04/07/2021] [Indexed: 12/13/2022] Open
Abstract
Building a functional nervous system requires the coordinated actions of many glial cells. In the vertebrate central nervous system (CNS), oligodendrocytes myelinate neuronal axons to increase conduction velocity and provide trophic support. Myelination can be modified by local signaling at the axon-myelin interface, potentially adapting sheaths to support the metabolic needs and physiology of individual neurons. However, neurons and oligodendrocytes are not wholly responsible for crafting the myelination patterns seen in vivo. Other cell types of the CNS, including microglia and astrocytes, modify myelination. In this review, I cover the contributions of non-neuronal, non-oligodendroglial cells to the formation, maintenance, and pruning of myelin sheaths. I address ways that these cell types interact with the oligodendrocyte lineage throughout development to modify myelination. Additionally, I discuss mechanisms by which these cells may indirectly tune myelination by regulating neuronal activity. Understanding how glial-glial interactions regulate myelination is essential for understanding how the brain functions as a whole and for developing strategies to repair myelin in disease.
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Affiliation(s)
- Alexandria N. Hughes
- Section of Developmental Biology, Department of Pediatrics, University of Colorado, Aurora, Aurora, CO, United States
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50
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A morphological analysis of activity-dependent myelination and myelin injury in transitional oligodendrocytes. Sci Rep 2021; 11:9588. [PMID: 33953273 PMCID: PMC8099889 DOI: 10.1038/s41598-021-88887-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 04/07/2021] [Indexed: 12/13/2022] Open
Abstract
Neuronal activity is established as a driver of oligodendrocyte (OL) differentiation and myelination. The concept of activity-dependent myelin plasticity, and its role in cognition and disease, is gaining support. Methods capable of resolving changes in the morphology of individual myelinating OL would advance our understanding of myelin plasticity and injury, thus we adapted a labelling approach involving Semliki Forest Virus (SFV) vectors to resolve and quantify the 3-D structure of OL processes and internodes in cerebellar slice cultures. We first demonstrate the utility of the approach by studying changes in OL morphology after complement-mediated injury. SFV vectors injected into cerebellar white matter labelled transitional OL (TOL), whose characteristic mixture of myelinating and non-myelinating processes exhibited significant degeneration after complement injury. The method was also capable of resolving finer changes in morphology related to neuronal activity. Prolonged suppression of neuronal activity, which reduced myelination, selectively decreased the length of putative internodes, and the proportion of process branches that supported them, while leaving other features of process morphology unaltered. Overall this work provides novel information on the morphology of TOL, and their response to conditions that alter circuit function or induce demyelination.
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