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Riboni-Verri G, Chen BS, McMurran CE, Halliwell GJ, Brown JWL, Coles AJ, Cunniffe NG. Visual outcome measures in clinical trials of remyelinating drugs. BMJ Neurol Open 2024; 6:e000560. [PMID: 38389586 PMCID: PMC10882304 DOI: 10.1136/bmjno-2023-000560] [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: 10/16/2023] [Accepted: 01/15/2024] [Indexed: 02/24/2024] Open
Abstract
One of the most promising approaches to delay, prevent or reverse disability progression in multiple sclerosis (MS) is to enhance endogenous remyelination and limit axonal degeneration. In clinical trials of remyelinating drugs, there is a need for reliable, sensitive and clinically relevant outcome measures. The visual pathway, which is frequently affected by MS, provides a unique model system to evaluate remyelination of acute and chronic MS lesions in vivo and non-invasively. In this review, we discuss the different measures that have been used and scrutinise visual outcome measure selection in current and future remyelination trials.
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Affiliation(s)
- Gioia Riboni-Verri
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
- Cambridge Clinical Vision Laboratory, University of Cambridge, Cambridge, UK
| | - Benson S Chen
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
- Cambridge Clinical Vision Laboratory, University of Cambridge, Cambridge, UK
| | - Christopher E McMurran
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
- Cambridge Clinical Vision Laboratory, University of Cambridge, Cambridge, UK
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - Gregory J Halliwell
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - J William L Brown
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
- Clinical Outcomes Research Unit (CORe), University of Melbourne, Melborune, Melborune, Australia
| | - Alasdair J Coles
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
- Cambridge Clinical Vision Laboratory, University of Cambridge, Cambridge, UK
| | - Nick G Cunniffe
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
- Cambridge Clinical Vision Laboratory, University of Cambridge, Cambridge, UK
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2
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Zahaf A, Kassoussi A, Hutteau-Hamel T, Mellouk A, Marie C, Zoupi L, Tsouki F, Mattern C, Bobé P, Schumacher M, Williams A, Parras C, Traiffort E. Androgens show sex-dependent differences in myelination in immune and non-immune murine models of CNS demyelination. Nat Commun 2023; 14:1592. [PMID: 36949062 PMCID: PMC10033728 DOI: 10.1038/s41467-023-36846-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 02/20/2023] [Indexed: 03/24/2023] Open
Abstract
Neuroprotective, anti-inflammatory, and remyelinating properties of androgens are well-characterized in demyelinated male mice and men suffering from multiple sclerosis. However, androgen effects mediated by the androgen receptor (AR), have been only poorly studied in females who make low androgen levels. Here, we show a predominant microglial AR expression in demyelinated lesions from female mice and women with multiple sclerosis, but virtually undetectable AR expression in lesions from male animals and men with multiple sclerosis. In female mice, androgens and estrogens act in a synergistic way while androgens drive microglia response towards regeneration. Transcriptomic comparisons of demyelinated mouse spinal cords indicate that, regardless of the sex, androgens up-regulate genes related to neuronal function integrity and myelin production. Depending on the sex, androgens down-regulate genes related to the immune system in females and lipid catabolism in males. Thus, androgens are required for proper myelin regeneration in females and therapeutic approaches of demyelinating diseases need to consider male-female differences.
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Affiliation(s)
- Amina Zahaf
- U1195 Inserm, Paris-Saclay University, Kremlin-Bicêtre, France
| | | | | | - Amine Mellouk
- UMR996 Inserm, Paris-Saclay University, Clamart, France
| | | | - Lida Zoupi
- Centre for Regenerative Medicine, Institute for Regeneration and Repair, The University of Edinburgh, Edinburgh BioQuarter, Edinburgh, UK
| | - Foteini Tsouki
- Centre for Regenerative Medicine, Institute for Regeneration and Repair, The University of Edinburgh, Edinburgh BioQuarter, Edinburgh, UK
| | | | - Pierre Bobé
- UMR996 Inserm, Paris-Saclay University, Clamart, France
| | | | - Anna Williams
- Centre for Regenerative Medicine, Institute for Regeneration and Repair, The University of Edinburgh, Edinburgh BioQuarter, Edinburgh, UK
| | - Carlos Parras
- Paris Brain Institute, Sorbonne University, Paris, France
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3
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Liu Y, Wong TTW, Shi J, He Y, Nie L, Wang LV. Label-free differential imaging of cellular components in mouse brain tissue by wide-band photoacoustic microscopy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.27.530195. [PMID: 36909457 PMCID: PMC10002654 DOI: 10.1101/2023.02.27.530195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/05/2023]
Abstract
Mapping diverse cellular components with high spatial resolution is important to interrogate biological systems and study disease pathogenesis. Conventional optical imaging techniques for mapping biomolecular profiles with differential staining and labeling methods are cumbersome. Different types of cellular components exhibit distinctive characteristic absorption spectra across a wide wavelength range. By virtue of this property, a lab-made wide-band optical-resolution photoacoustic microscopy (wbOR-PAM) system, which covers wavelengths from the ultraviolet and visible to the shortwave infrared regions, was designed and developed to capture multiple cellular components in 300-μm-thick brain slices at nine different wavelengths without repetitive staining and complicated processing. This wbOR-PAM system provides abundant spectral information. A reflective objective lens with an infinite conjugate design was applied to focus laser beams with different wavelengths, avoiding chromatic aberration. The molecular components of complex brain slices were probed without labeling. The findings of the present study demonstrated a distinctive absorption of phospholipids, a major component of the cell membrane, brain, and nervous system, at 1690 nm and revealed their precise distribution with microscopic resolution in a mouse brain, for the first time. This novel imaging modality provides a new opportunity to investigate important biomolecular components without either labeling or lengthy specimen processing, thus, laying the groundwork for revealing cellular mechanisms involved in disease pathogenesis.
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Affiliation(s)
- Yajing Liu
- Department of Ultrasound in Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Zhejiang University, Hangzhou, 310009, Zhejiang, China
- Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Terence T W Wong
- Translational and Advanced Bioimaging Laboratory, Department of Chemical and Biological Engineering, Hong Kong University of Science and Technology, Hong Kong, China
| | - Junhui Shi
- Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Yun He
- Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Liming Nie
- Medical Research Institute, Guangdong Provincial People’s Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510080, China
| | - Lihong V. Wang
- Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
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4
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Talidou A, Frankland PW, Mabbott D, Lefebvre J. Homeostatic coordination and up-regulation of neural activity by activity-dependent myelination. NATURE COMPUTATIONAL SCIENCE 2022; 2:665-676. [PMID: 38177260 DOI: 10.1038/s43588-022-00315-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 08/10/2022] [Indexed: 01/06/2024]
Abstract
Activity-dependent myelination (ADM) is a fundamental dimension of brain plasticity through which myelin changes as a function of neural activity. Mediated by structural changes in glia, ADM notably regulates axonal conduction velocity. Yet, it remains unclear how neural activity impacts myelination to orchestrate the timing of neural signalling, and how ADM shapes neural activity. We developed a model of spiking neurons enhanced with neuron-oligodendrocyte feedback and examined the relationship between ADM and neural activity. We found that ADM implements a homeostatic gain control mechanism that enhances neural firing rates and correlations through the temporal coordination of action potentials as axon lengths increase. Stimuli engage ADM plasticity to trigger bidirectional and reversible changes in conduction delays, as may occur during learning. Furthermore, ADM was found to enhance information transmission under various types of time-varying stimuli. These results highlight the role of ADM in shaping neural activity and communication.
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Affiliation(s)
- Afroditi Talidou
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada.
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.
| | - Paul W Frankland
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada
| | - Donald Mabbott
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada
| | - Jérémie Lefebvre
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Physics, University of Ottawa, Ottawa, Ontario, Canada
- Department of Mathematics, University of Toronto, Toronto, Ontario, Canada
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5
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Neely SA, Lyons DA. Insights Into Central Nervous System Glial Cell Formation and Function From Zebrafish. Front Cell Dev Biol 2021; 9:754606. [PMID: 34912801 PMCID: PMC8666443 DOI: 10.3389/fcell.2021.754606] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/05/2021] [Indexed: 12/23/2022] Open
Abstract
The term glia describes a heterogenous collection of distinct cell types that make up a large proportion of our nervous system. Although once considered the glue of the nervous system, the study of glial cells has evolved significantly in recent years, with a large body of literature now highlighting their complex and diverse roles in development and throughout life. This progress is due, in part, to advances in animal models in which the molecular and cellular mechanisms of glial cell development and function as well as neuron-glial cell interactions can be directly studied in vivo in real time, in intact neural circuits. In this review we highlight the instrumental role that zebrafish have played as a vertebrate model system for the study of glial cells, and discuss how the experimental advantages of the zebrafish lend themselves to investigate glial cell interactions and diversity. We focus in particular on recent studies that have provided insight into the formation and function of the major glial cell types in the central nervous system in zebrafish.
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Affiliation(s)
- Sarah A. Neely
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - David A. Lyons
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
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6
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Jankowska E, Hammar I. The plasticity of nerve fibers: the prolonged effects of polarization of afferent fibers. J Neurophysiol 2021; 126:1568-1591. [PMID: 34525323 DOI: 10.1152/jn.00718.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The review surveys various aspects of the plasticity of nerve fibers, in particular the prolonged increase in their excitability evoked by polarization, focusing on a long-lasting increase in the excitability of myelinated afferent fibers traversing the dorsal columns of the spinal cord. We review the evidence that increased axonal excitability 1) follows epidurally applied direct current (DC) as well as relatively short (5 or 10 ms) current pulses and synaptically evoked intrinsic field potentials; 2) critically depends on the polarization of branching regions of afferent fibers at the sites where they bifurcate and give off axon collaterals entering the spinal gray matter in conjunction with actions of extrasynaptic GABAA membrane receptors; and 3) shares the feature of being activity-independent with the short-lasting effects of polarization of peripheral nerve fibers. A comparison between the polarization evoked sustained increase in the excitability of dorsal column fibers and spinal motoneurons (plateau potentials) indicates the possibility that they are mediated by partly similar membrane channels (including noninactivating type L Cav++ 1.3 but not Na+ channels) and partly different mechanisms. We finally consider under which conditions transspinally applied DC (tsDCS) might reproduce the effects of epidural polarization on dorsal column fibers and the possible advantages of increased excitability of afferent fibers for the rehabilitation of motor and sensory functions after spinal cord injuries.NEW & NOTEWORTHY This review supplements previous reviews of properties of nerve fibers by surveying recent experimental evidence for their long-term plasticity. It also extends recent descriptions of spinal effects of DC by reviewing effects of polarization of afferent nerve fibers within the dorsal columns, the mechanisms most likely underlying the long-lasting increase in their excitability and possible clinical implications.
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Affiliation(s)
- Elzbieta Jankowska
- Department of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Ingela Hammar
- Department of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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7
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Nishiyama A, Shimizu T, Sherafat A, Richardson WD. Life-long oligodendrocyte development and plasticity. Semin Cell Dev Biol 2021; 116:25-37. [PMID: 33741250 PMCID: PMC8292179 DOI: 10.1016/j.semcdb.2021.02.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 02/16/2021] [Accepted: 02/17/2021] [Indexed: 12/25/2022]
Abstract
Oligodendrocyte precursor cells (OPCs) originate in localized germinal zones in the embryonic neural tube, then migrate and proliferate to populate the entire central nervous system, both white and gray matter. They divide and generate myelinating oligodendrocytes (OLs) throughout postnatal and adult life. OPCs express NG2 and platelet-derived growth factor receptor alpha subunit (PDGFRα), two functionally important cell surface proteins, which are also widely used as markers for OPCs. The proliferation of OPCs, their terminal differentiation into OLs, survival of new OLs, and myelin synthesis are orchestrated by signals in the local microenvironment. We discuss advances in our mechanistic understanding of paracrine effects, including those mediated through PDGFRα and neuronal activity-dependent signals such as those mediated through AMPA receptors in OL survival and myelination. Finally, we review recent studies supporting the role of new OL production and “adaptive myelination” in specific behaviours and cognitive processes contributing to learning and long-term memory formation. Our article is not intended to be comprehensive but reflects the authors’ past and present interests.
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Affiliation(s)
- Akiko Nishiyama
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT 06269-3156, USA.
| | - Takahiro Shimizu
- Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, UK
| | - Amin Sherafat
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT 06269-3156, USA
| | - William D Richardson
- Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, UK.
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8
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Cunniffe N, Coles A. Promoting remyelination in multiple sclerosis. J Neurol 2021; 268:30-44. [PMID: 31190170 PMCID: PMC7815564 DOI: 10.1007/s00415-019-09421-x] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 06/03/2019] [Accepted: 06/05/2019] [Indexed: 02/07/2023]
Abstract
The greatest unmet need in multiple sclerosis (MS) are treatments that delay, prevent or reverse progression. One of the most tractable strategies to achieve this is to therapeutically enhance endogenous remyelination; doing so restores nerve conduction and prevents neurodegeneration. The biology of remyelination-centred on the activation, migration, proliferation and differentiation of oligodendrocyte progenitors-has been increasingly clearly defined and druggable targets have now been identified in preclinical work leading to early phase clinical trials. With some phase 2 studies reporting efficacy, the prospect of licensed remyelinating treatments in MS looks increasingly likely. However, there remain many unanswered questions and recent research has revealed a further dimension of complexity to this process that has refined our view of the barriers to remyelination in humans. In this review, we describe the process of remyelination, why this fails in MS, and the latest research that has given new insights into this process. We also discuss the translation of this research into clinical trials, highlighting the treatments that have been tested to date, and the different methods of detecting remyelination in people.
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Affiliation(s)
- Nick Cunniffe
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
| | - Alasdair Coles
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
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9
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Nelson HN, Treichel AJ, Eggum EN, Martell MR, Kaiser AJ, Trudel AG, Gronseth JR, Maas ST, Bergen S, Hines JH. Individual neuronal subtypes control initial myelin sheath growth and stabilization. Neural Dev 2020; 15:12. [PMID: 32988384 PMCID: PMC7523326 DOI: 10.1186/s13064-020-00149-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 09/17/2020] [Indexed: 01/21/2023] Open
Abstract
Background In the developing central nervous system, pre-myelinating oligodendrocytes sample candidate nerve axons by extending and retracting process extensions. Some contacts stabilize, leading to the initiation of axon wrapping, nascent myelin sheath formation, concentric wrapping and sheath elongation, and sheath stabilization or pruning by oligodendrocytes. Although axonal signals influence the overall process of myelination, the precise oligodendrocyte behaviors that require signaling from axons are not completely understood. In this study, we investigated whether oligodendrocyte behaviors during the early events of myelination are mediated by an oligodendrocyte-intrinsic myelination program or are over-ridden by axonal factors. Methods To address this, we utilized in vivo time-lapse imaging in embryonic and larval zebrafish spinal cord during the initial hours and days of axon wrapping and myelination. Transgenic reporter lines marked individual axon subtypes or oligodendrocyte membranes. Results In the larval zebrafish spinal cord, individual axon subtypes supported distinct nascent sheath growth rates and stabilization frequencies. Oligodendrocytes ensheathed individual axon subtypes at different rates during a two-day period after initial axon wrapping. When descending reticulospinal axons were ablated, local spinal axons supported a constant ensheathment rate despite the increased ratio of oligodendrocytes to target axons. Conclusion We conclude that properties of individual axon subtypes instruct oligodendrocyte behaviors during initial stages of myelination by differentially controlling nascent sheath growth and stabilization.
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Affiliation(s)
| | | | - Erin N Eggum
- Biology Department, Winona State University, Winona, MN, USA
| | | | - Amanda J Kaiser
- Biology Department, Winona State University, Winona, MN, USA
| | - Allie G Trudel
- Biology Department, Winona State University, Winona, MN, USA
| | | | - Samantha T Maas
- Biology Department, Winona State University, Winona, MN, USA
| | - Silas Bergen
- Biology Department, Winona State University, Winona, MN, USA
| | - Jacob H Hines
- Biology Department, Winona State University, Winona, MN, USA.
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10
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Egbu E. Bilateral Peripapillary Retinal Nerve Fiber Layer Myelination in a 26-Year-Old Man. Cureus 2020; 12:e9960. [PMID: 32983664 PMCID: PMC7510502 DOI: 10.7759/cureus.9960] [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] [Indexed: 11/23/2022] Open
Abstract
Myelination is an uncommon condition that rarely causes visual impairment. We report a case of a young man with bilateral peripapillary nerve fiber layer myelination and visual impairment. The patient's complaints, clinical history, and systemic review were noted. Visual acuity test, objective and subjective refraction, ocular motility, fundus examination, optical coherence tomography, and low vision test, were performed. We compared our findings with published articles. We suggest that optic neuropathy was the cause of visual impairment in the patient.
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11
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Yazdankhah M, Shang P, Ghosh S, Hose S, Liu H, Weiss J, Fitting CS, Bhutto IA, Zigler JS, Qian J, Sahel JA, Sinha D, Stepicheva NA. Role of glia in optic nerve. Prog Retin Eye Res 2020; 81:100886. [PMID: 32771538 DOI: 10.1016/j.preteyeres.2020.100886] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 07/09/2020] [Accepted: 07/20/2020] [Indexed: 12/13/2022]
Abstract
Glial cells are critically important for maintenance of neuronal activity in the central nervous system (CNS), including the optic nerve (ON). However, the ON has several unique characteristics, such as an extremely high myelination level of retinal ganglion cell (RGC) axons throughout the length of the nerve (with virtually all fibers myelinated by 7 months of age in humans), lack of synapses and very narrow geometry. Moreover, the optic nerve head (ONH) - a region where the RGC axons exit the eye - represents an interesting area that is morphologically distinct in different species. In many cases of multiple sclerosis (demyelinating disease of the CNS) vision problems are the first manifestation of the disease, suggesting that RGCs and/or glia in the ON are more sensitive to pathological conditions than cells in other parts of the CNS. Here, we summarize current knowledge on glial organization and function in the ON, focusing on glial support of RGCs. We cover both well-established concepts on the important role of glial cells in ON health and new findings, including novel insights into mechanisms of remyelination, microglia/NG2 cell-cell interaction, astrocyte reactivity and the regulation of reactive astrogliosis by mitochondrial fragmentation in microglia.
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Affiliation(s)
- Meysam Yazdankhah
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Peng Shang
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Sayan Ghosh
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Stacey Hose
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Haitao Liu
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Joseph Weiss
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Christopher S Fitting
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Imran A Bhutto
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - J Samuel Zigler
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jiang Qian
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - José-Alain Sahel
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Institut de la Vision, INSERM, CNRS, Sorbonne Université, F-75012, Paris, France
| | - Debasish Sinha
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Nadezda A Stepicheva
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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12
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Activity-dependent myelination: A glial mechanism of oscillatory self-organization in large-scale brain networks. Proc Natl Acad Sci U S A 2020; 117:13227-13237. [PMID: 32482855 DOI: 10.1073/pnas.1916646117] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Communication and oscillatory synchrony between distributed neural populations are believed to play a key role in multiple cognitive and neural functions. These interactions are mediated by long-range myelinated axonal fiber bundles, collectively termed as white matter. While traditionally considered to be static after development, white matter properties have been shown to change in an activity-dependent way through learning and behavior-a phenomenon known as white matter plasticity. In the central nervous system, this plasticity stems from oligodendroglia, which form myelin sheaths to regulate the conduction of nerve impulses across the brain, hence critically impacting neural communication. We here shift the focus from neural to glial contribution to brain synchronization and examine the impact of adaptive, activity-dependent changes in conduction velocity on the large-scale phase synchronization of neural oscillators. Using a network model based on primate large-scale white matter neuroanatomy, our computational and mathematical results show that such plasticity endows white matter with self-organizing properties, where conduction delay statistics are autonomously adjusted to ensure efficient neural communication. Our analysis shows that this mechanism stabilizes oscillatory neural activity across a wide range of connectivity gain and frequency bands, making phase-locked states more resilient to damage as reflected by diffuse decreases in connectivity. Critically, our work suggests that adaptive myelination may be a mechanism that enables brain networks with a means of temporal self-organization, resilience, and homeostasis.
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13
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Abstract
Cells of the oligodendrocyte lineage express a wide range of Ca2+ channels and receptors that regulate oligodendrocyte progenitor cell (OPC) and oligodendrocyte formation and function. Here we define those key channels and receptors that regulate Ca2+ signaling and OPC development and myelination. We then discuss how the regulation of intracellular Ca2+ in turn affects OPC and oligodendrocyte biology in the healthy nervous system and under pathological conditions. Activation of Ca2+ channels and receptors in OPCs and oligodendrocytes by neurotransmitters converges on regulating intracellular Ca2+, making Ca2+ signaling a central candidate mediator of activity-driven myelination. Indeed, recent evidence indicates that localized changes in Ca2+ in oligodendrocytes can regulate the formation and remodeling of myelin sheaths and perhaps additional functions of oligodendrocytes and OPCs. Thus, decoding how OPCs and myelinating oligodendrocytes integrate and process Ca2+ signals will be important to fully understand central nervous system formation, health, and function.
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Affiliation(s)
- Pablo M Paez
- Department of Pharmacology and Toxicology and Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences, The State University of New York, University at Buffalo, Buffalo, New York 14203, USA;
| | - David A Lyons
- Centre for Discovery Brain Sciences, Centre for Multiple Sclerosis Research, and Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH16 4SB, United Kingdom;
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14
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Initiation of CNS Myelination in the Optic Nerve Is Dependent on Axon Caliber. Cell Rep 2019; 25:544-550.e3. [PMID: 30332636 PMCID: PMC6258034 DOI: 10.1016/j.celrep.2018.09.052] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 07/19/2018] [Accepted: 09/13/2018] [Indexed: 11/20/2022] Open
Abstract
Emerging evidence suggests that neuronal signaling is important for oligodendrocyte myelination; however, the necessity of
this signaling during development is unclear. By eliminating dynamic neuronal signaling along the developing optic nerve, we find
that oligodendrocyte differentiation is not dependent on neuronal signaling and that the initiation of myelination is dependent on
a permissive substrate, namely supra-threshold axon caliber. Furthermore, we show that loss of dynamic neuronal signaling results
in hypermyelination of axons. We propose that oligodendrocyte differentiation is regulated by non-neuronal factors during optic
nerve development, whereas myelination is sensitive to the biophysical properties of axonal diameter. Mayoral et al. show that elimination of neuronal signaling via enucleation of the developing optic nerve of
Wlds mice results in normal oligodendrocyte differentiation but disrupted myelination. Myelination is rescued
when axons are enlarged prior to enucleation, showing that supra-threshold axon caliber, but not neuronal signaling, is necessary
for myelination.
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15
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Klingseisen A, Ristoiu AM, Kegel L, Sherman DL, Rubio-Brotons M, Almeida RG, Koudelka S, Benito-Kwiecinski SK, Poole RJ, Brophy PJ, Lyons DA. Oligodendrocyte Neurofascin Independently Regulates Both Myelin Targeting and Sheath Growth in the CNS. Dev Cell 2019; 51:730-744.e6. [PMID: 31761670 PMCID: PMC6912162 DOI: 10.1016/j.devcel.2019.10.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 09/10/2019] [Accepted: 10/17/2019] [Indexed: 01/06/2023]
Abstract
Selection of the correct targets for myelination and regulation of myelin sheath growth are essential for central nervous system (CNS) formation and function. Through a genetic screen in zebrafish and complementary analyses in mice, we find that loss of oligodendrocyte Neurofascin leads to mistargeting of myelin to cell bodies, without affecting targeting to axons. In addition, loss of Neurofascin reduces CNS myelination by impairing myelin sheath growth. Time-lapse imaging reveals that the distinct myelinating processes of individual oligodendrocytes can engage in target selection and sheath growth at the same time and that Neurofascin concomitantly regulates targeting and growth. Disruption to Caspr, the neuronal binding partner of oligodendrocyte Neurofascin, also impairs myelin sheath growth, likely reflecting its association in an adhesion complex at the axon-glial interface with Neurofascin. Caspr does not, however, affect myelin targeting, further indicating that Neurofascin independently regulates distinct aspects of CNS myelination by individual oligodendrocytes in vivo. Single oligodendrocytes coordinate myelin targeting and growth at the same time Oligodendrocyte Neurofascin prevents myelination of cell bodies Oligodendrocyte Neurofascin promotes myelin sheath growth The neuronal binding partner of Neurofascin, Caspr, promotes myelin sheath growth
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Affiliation(s)
- Anna Klingseisen
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Ana-Maria Ristoiu
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Linde Kegel
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Diane L Sherman
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Maria Rubio-Brotons
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Rafael G Almeida
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Sigrid Koudelka
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | | | - Richard J Poole
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Peter J Brophy
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - David A Lyons
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK.
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16
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Suminaite D, Lyons DA, Livesey MR. Myelinated axon physiology and regulation of neural circuit function. Glia 2019; 67:2050-2062. [PMID: 31233642 PMCID: PMC6772175 DOI: 10.1002/glia.23665] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 05/28/2019] [Accepted: 06/06/2019] [Indexed: 12/15/2022]
Abstract
The study of structural and functional plasticity in the central nervous system (CNS) to date has focused primarily on that of neurons and synapses. However, more recent studies implicate glial cells as key regulators of neural circuit function. Among these, the myelinating glia of the CNS, oligodendrocytes, have been shown to be responsive to extrinsic signals including neuronal activity, and in turn, tune neurophysiological function. Due to the fact that myelin fundamentally alters the conduction properties of axons, much attention has focused on how dynamic regulation of myelination might represent a form of functional plasticity. Here, we highlight recent research that indicates that it is not only myelin, but essentially all the function-regulating components of the myelinated axon that are responsive to neuronal activity. For example, the axon initial segment, nodes of Ranvier, heminodes, axonal termini, and the morphology of the axon itself all exhibit the potential to respond to neuronal activity, and in so doing might underpin specific functional outputs. We also highlight emerging evidence that the myelin sheath itself has a rich physiology capable of influencing axonal physiology. We suggest that to fully understand nervous system plasticity we need to consider the fact that myelinated axon is an integrated functional unit and adaptations that influence the entire functional unit are likely to underpin modifications to neural circuit function.
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Affiliation(s)
| | - David A. Lyons
- Centre for Discovery Brain SciencesUniversity of EdinburghEdinburghUK
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17
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Cyfip1 haploinsufficient rats show white matter changes, myelin thinning, abnormal oligodendrocytes and behavioural inflexibility. Nat Commun 2019; 10:3455. [PMID: 31371763 PMCID: PMC6671959 DOI: 10.1038/s41467-019-11119-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 06/20/2019] [Indexed: 11/30/2022] Open
Abstract
The biological basis of the increased risk for psychiatric disorders seen in 15q11.2 copy number deletion is unknown. Previous work has shown disturbances in white matter tracts in human carriers of the deletion. Here, in a novel rat model, we recapitulated low dosage of the candidate risk gene CYFIP1 present within the 15q11.2 interval. Using diffusion tensor imaging, we first showed extensive white matter changes in Cyfip1 mutant rats, which were most pronounced in the corpus callosum and external capsule. Transmission electron microscopy showed that these changes were associated with thinning of the myelin sheath in the corpus callosum. Myelin thinning was independent of changes in axon number or diameter but was associated with effects on mature oligodendrocytes, including aberrant intracellular distribution of myelin basic protein. Finally, we demonstrated effects on cognitive phenotypes sensitive to both disruptions in myelin and callosal circuitry. People with a genetic deletion of the 15q11.2 locus are at increased risk for psychiatric disorders and white matter disturbances, but the gene(s) responsible are unclear. Here, the authors show that low dosage of CYFIP1, present in the human 15q11.2 region, alters white matter structure and cognition in rats.
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18
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Dimas P, Montani L, Pereira JA, Moreno D, Trötzmüller M, Gerber J, Semenkovich CF, Köfeler HC, Suter U. CNS myelination and remyelination depend on fatty acid synthesis by oligodendrocytes. eLife 2019; 8:44702. [PMID: 31063129 PMCID: PMC6504237 DOI: 10.7554/elife.44702] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Accepted: 04/27/2019] [Indexed: 12/26/2022] Open
Abstract
Oligodendrocytes (OLs) support neurons and signal transmission in the central nervous system (CNS) by enwrapping axons with myelin, a lipid-rich membrane structure. We addressed the significance of fatty acid (FA) synthesis in OLs by depleting FA synthase (FASN) from OL progenitor cells (OPCs) in transgenic mice. While we detected no effects in proliferation and differentiation along the postnatal OL lineage, we found that FASN is essential for accurate myelination, including myelin growth. Increasing dietary lipid intake could partially compensate for the FASN deficiency. Furthermore, FASN contributes to correct myelin lipid composition and stability of myelinated axons. Moreover, we depleted FASN specifically in adult OPCs to examine its relevance for remyelination. Applying lysolecithin-induced focal demyelinating spinal cord lesions, we found that FA synthesis is essential to sustain adult OPC-derived OLs and efficient remyelination. We conclude that FA synthesis in OLs plays key roles in CNS myelination and remyelination.
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Affiliation(s)
- Penelope Dimas
- Institute of Molecular Health Sciences, Swiss Federal Institute of Technology, ETH Zürich, Zürich, Switzerland
| | - Laura Montani
- Institute of Molecular Health Sciences, Swiss Federal Institute of Technology, ETH Zürich, Zürich, Switzerland
| | - Jorge A Pereira
- Institute of Molecular Health Sciences, Swiss Federal Institute of Technology, ETH Zürich, Zürich, Switzerland
| | - Daniel Moreno
- Institute of Molecular Health Sciences, Swiss Federal Institute of Technology, ETH Zürich, Zürich, Switzerland
| | | | - Joanne Gerber
- Institute of Molecular Health Sciences, Swiss Federal Institute of Technology, ETH Zürich, Zürich, Switzerland
| | - Clay F Semenkovich
- Division of Endocrinology, Metabolism and Lipid Research, Washington University Medical School, St. Louis, United States
| | - Harald C Köfeler
- Center for Medical Research, Medical University of Graz, Graz, Austria
| | - Ueli Suter
- Institute of Molecular Health Sciences, Swiss Federal Institute of Technology, ETH Zürich, Zürich, Switzerland
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19
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Zakaria M, Ferent J, Hristovska I, Laouarem Y, Zahaf A, Kassoussi A, Mayeur ME, Pascual O, Charron F, Traiffort E. The Shh receptor Boc is important for myelin formation and repair. Development 2019; 146:146/9/dev172502. [PMID: 31048318 DOI: 10.1242/dev.172502] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Accepted: 03/28/2019] [Indexed: 12/25/2022]
Abstract
Myelination leads to the formation of myelin sheaths surrounding neuronal axons and is crucial for function, plasticity and repair of the central nervous system (CNS). It relies on the interaction of the axons and the oligodendrocytes: the glial cells producing CNS myelin. Here, we have investigated the role of a crucial component of the Sonic hedgehog (Shh) signalling pathway, the co-receptor Boc, in developmental and repairing myelination. During development, Boc mutant mice display a transient decrease in oligodendroglial cell density together with delayed myelination. Despite recovery of oligodendroglial cells at later stages, adult mutants still exhibit a lower production of myelin basic protein correlated with a significant decrease in the calibre of callosal axons and a reduced amount of the neurofilament NF-M. During myelin repair, the altered OPC differentiation observed in the mutant is reminiscent of the phenotype observed after blockade of Shh signalling. In addition, Boc mutant microglia/macrophages unexpectedly exhibit the apparent inability to transition from a highly to a faintly ramified morphology in vivo Altogether, these results identify Boc as an important component of myelin formation and repair.
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Affiliation(s)
- Mary Zakaria
- INSERM-University Paris-Sud/Paris-Saclay; Diseases and Hormones of the Nervous System, U1195, 80 rue du Général Leclerc, F-94276, Le Kremlin-Bicêtre, France
| | - Julien Ferent
- IRCM, Molecular Biology of Neural Development, 110 Pine Avenue West, Montreal, Quebec H2W 1R7, Canada; Department of Medicine, University of Montreal, Montreal, Quebec, Canada; McGill University, Montreal, Quebec, Canada
| | - Ines Hristovska
- Institut NeuroMyoGène CNRS UMR 5310-INSERM U1217-Université Claude Bernard Lyon 1, Faculté de Médecine et de Pharmacie 69008 Lyon, France
| | - Yousra Laouarem
- INSERM-University Paris-Sud/Paris-Saclay; Diseases and Hormones of the Nervous System, U1195, 80 rue du Général Leclerc, F-94276, Le Kremlin-Bicêtre, France
| | - Amina Zahaf
- INSERM-University Paris-Sud/Paris-Saclay; Diseases and Hormones of the Nervous System, U1195, 80 rue du Général Leclerc, F-94276, Le Kremlin-Bicêtre, France
| | - Abdelmoumen Kassoussi
- INSERM-University Paris-Sud/Paris-Saclay; Diseases and Hormones of the Nervous System, U1195, 80 rue du Général Leclerc, F-94276, Le Kremlin-Bicêtre, France
| | - Marie-Eve Mayeur
- Institut NeuroMyoGène CNRS UMR 5310-INSERM U1217-Université Claude Bernard Lyon 1, Faculté de Médecine et de Pharmacie 69008 Lyon, France
| | - Olivier Pascual
- Institut NeuroMyoGène CNRS UMR 5310-INSERM U1217-Université Claude Bernard Lyon 1, Faculté de Médecine et de Pharmacie 69008 Lyon, France
| | - Frederic Charron
- IRCM, Molecular Biology of Neural Development, 110 Pine Avenue West, Montreal, Quebec H2W 1R7, Canada; Department of Medicine, University of Montreal, Montreal, Quebec, Canada; McGill University, Montreal, Quebec, Canada
| | - Elisabeth Traiffort
- INSERM-University Paris-Sud/Paris-Saclay; Diseases and Hormones of the Nervous System, U1195, 80 rue du Général Leclerc, F-94276, Le Kremlin-Bicêtre, France
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20
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Carbofuran hampers oligodendrocytes development leading to impaired myelination in the hippocampus of rat brain. Neurotoxicology 2019; 70:161-179. [DOI: 10.1016/j.neuro.2018.11.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 11/14/2018] [Accepted: 11/20/2018] [Indexed: 11/21/2022]
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21
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Sun LO, Mulinyawe SB, Collins HY, Ibrahim A, Li Q, Simon DJ, Tessier-Lavigne M, Barres BA. Spatiotemporal Control of CNS Myelination by Oligodendrocyte Programmed Cell Death through the TFEB-PUMA Axis. Cell 2018; 175:1811-1826.e21. [PMID: 30503207 PMCID: PMC6295215 DOI: 10.1016/j.cell.2018.10.044] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Revised: 08/01/2018] [Accepted: 10/19/2018] [Indexed: 12/16/2022]
Abstract
Nervous system function depends on proper myelination for insulation and critical trophic support for axons. Myelination is tightly regulated spatially and temporally, but how it is controlled molecularly remains largely unknown. Here, we identified key molecular mechanisms governing the regional and temporal specificity of CNS myelination. We show that transcription factor EB (TFEB) is highly expressed by differentiating oligodendrocytes and that its loss causes precocious and ectopic myelination in many parts of the murine brain. TFEB functions cell-autonomously through PUMA induction and Bax-Bak activation to promote programmed cell death of a subset of premyelinating oligodendrocytes, allowing selective elimination of oligodendrocytes in normally unmyelinated brain regions. This pathway is conserved across diverse brain areas and is critical for myelination timing. Our findings define an oligodendrocyte-intrinsic mechanism underlying the spatiotemporal specificity of CNS myelination, shedding light on how myelinating glia sculpt the nervous system during development.
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Affiliation(s)
- Lu O Sun
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Sara B Mulinyawe
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Hannah Y Collins
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Adiljan Ibrahim
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Qingyun Li
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - David J Simon
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | | | - Ben A Barres
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
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22
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Almeida RG. The Rules of Attraction in Central Nervous System Myelination. Front Cell Neurosci 2018; 12:367. [PMID: 30374292 PMCID: PMC6196289 DOI: 10.3389/fncel.2018.00367] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 09/27/2018] [Indexed: 12/12/2022] Open
Abstract
The wrapping of myelin around axons is crucial for the development and function of the central nervous system (CNS) of vertebrates, greatly regulating the conduction of action potentials. Oligodendrocytes, the myelinating glia of the CNS, have an intrinsic tendency to wrap myelin around any permissive structure in vitro, but in vivo, myelin is targeted with remarkable specificity only to certain axons. Despite the importance of myelination, the mechanisms by which oligodendrocytes navigate a complex milieu that includes many types of cells and their cellular projections and select only certain axons for myelination remains incompletely understood. In this Mini-review, I highlight recent studies that shed light on the molecular and cellular rules governing CNS myelin targeting.
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Affiliation(s)
- Rafael Góis Almeida
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, United Kingdom
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23
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Tan Z, Kang T, Zhang X, Tong Y, Chen S. Nerve growth factor prevents arsenic-induced toxicity in PC12 cells through the AKT/GSK-3β/NFAT pathway. J Cell Physiol 2018; 234:4726-4738. [PMID: 30256405 DOI: 10.1002/jcp.27255] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 07/25/2018] [Indexed: 12/13/2022]
Abstract
The potential risk of arsenic-related neurodegeneration has been a growing concern. Arsenic exposure has been reported to disrupt neurite growth and neuron body integrity in vitro; however, its underlying mechanism remains unclear. Previously, we showed that arsenic sulfide (AS) exerted cytotoxicity in gastric and colon cancer cells through regulating nuclear factor of the activated T cells (NFAT) pathway. The NFAT pathway regulates axon path finding and neural development. Using neural crest cell line PC12 cells as a model, here we show that AS caused mitochondrial membrane potential collapse, reactive oxygen species production, and cytochrome c release, leading to mitochondria-mediated apoptosis via the AKT/GSK-3β/NFAT pathway. Increased glycogen synthase kinase-3 beta (GSK-3β) activation leads to the inactivation of NFAT and its antiapoptotic effects. Through inhibiting GSK-3β activity, both nerve growth factor (NGF) and Tideglusib, a GSK-3β inhibitor partially rescued the PC12 cells from the AS-induced cytotoxicity and restored the expression of NFATc3. In addition, overexpression of NFATc3 stimulated neurite outgrowth and potentiated the effect of NGF on promoting the neurite outgrowth. Collectively, our results show that NFATc3 serves as the downstream target of NGF and plays a key role in preventing AS-induced neurotoxicity through regulating the AKT/GSK-3β/NFAT pathway in PC12 cells.
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Affiliation(s)
- Zhen Tan
- Department of Oncology, Xin Hua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Ting Kang
- Department of Oncology, Xin Hua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Xiuli Zhang
- Department of Oncology, Xin Hua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yingying Tong
- Department of Oncology, Xin Hua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Siyu Chen
- Department of Oncology, Xin Hua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
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24
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Marin MA, Carmichael ST. Stroke in CNS white matter: Models and mechanisms. Neurosci Lett 2018; 684:193-199. [PMID: 30098384 DOI: 10.1016/j.neulet.2018.07.039] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 07/03/2018] [Accepted: 07/30/2018] [Indexed: 12/14/2022]
Abstract
White matter stroke (WMS) is a debilitating disorder, which is characterized by the formation of ischemic lesions along subcortical white matter tracts of the central nervous system. Initial infarction during the early stages of the disease is often asymptomatic and is thus considered a form of silent stroke. However, over time lesions accumulate, resulting in severe cognitive and motor decline of which there are no known therapies. Functional imaging and post mortem analysis of patients demonstrates a loss of oligodendrocytes and the subsequent damage of myelin as a primary hallmark of WMS lesions. Though the adult mammalian brain maintains the capacity to regenerate adult oligodendrocytes, this process is blocked in the infarcted white matter thereby preventing remyelination. Recent evidence suggests that activation of neural circuits via motor training or direct stimulation drives oligodendrogenesis and de novo myelin synthesis, opening a potential avenue for therapy in WMS.
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Affiliation(s)
- Miguel Alejandro Marin
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, 9009, United States.
| | - S Thomas Carmichael
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, 9009, United States.
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25
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Almeida RG, Pan S, Cole KLH, Williamson JM, Early JJ, Czopka T, Klingseisen A, Chan JR, Lyons DA. Myelination of Neuronal Cell Bodies when Myelin Supply Exceeds Axonal Demand. Curr Biol 2018; 28:1296-1305.e5. [PMID: 29628374 PMCID: PMC5912901 DOI: 10.1016/j.cub.2018.02.068] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 02/02/2018] [Accepted: 02/23/2018] [Indexed: 01/10/2023]
Abstract
The correct targeting of myelin is essential for nervous system formation and function. Oligodendrocytes in the CNS myelinate some axons, but not others, and do not myelinate structures including cell bodies and dendrites [1]. Recent studies indicate that extrinsic signals, such as neuronal activity [2, 3] and cell adhesion molecules [4], can bias myelination toward some axons and away from cell bodies and dendrites, indicating that, in vivo, neuronal and axonal cues regulate myelin targeting. In vitro, however, oligodendrocytes have an intrinsic propensity to myelinate [5, 6, 7] and can promiscuously wrap inert synthetic structures resembling neuronal processes [8, 9] or cell bodies [4]. A current therapeutic goal for the treatment of demyelinating diseases is to greatly promote oligodendrogenesis [10, 11, 12, 13]; thus, it is important to test how accurately extrinsic signals regulate the oligodendrocyte’s intrinsic program of myelination in vivo. Here, we test the hypothesis that neurons regulate myelination with sufficient stringency to always ensure correct targeting. Surprisingly, however, we find that myelin targeting in vivo is not very stringent and that mistargeting occurs readily when oligodendrocyte and myelin supply exceed axonal demand. We find that myelin is mistargeted to neuronal cell bodies in zebrafish mutants with fewer axons and independently in drug-treated zebrafish with increased oligodendrogenesis. Additionally, by increasing myelin production of oligodendrocytes in zebrafish and mice, we find that excess myelin is also inappropriately targeted to cell bodies. Our results suggest that balancing oligodendrocyte-intrinsic programs of myelin supply with axonal demand is essential for correct myelin targeting in vivo and highlight potential liabilities of strongly promoting oligodendrogenesis. Balance between axons and myelin production regulates its targeting in vivo Excess myelin is mistargeted to cell bodies Low, but not zero, level of mistargeting during normal development Potential implications for myelin-promoting therapies
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Affiliation(s)
- Rafael G Almeida
- Centre for Discovery Brain Sciences, University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Simon Pan
- Department of Neurology and Program in Neuroscience, University of California, San Francisco, 675 Nelson Rising Lane, San Francisco, CA 94143, USA
| | - Katy L H Cole
- Centre for Discovery Brain Sciences, University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Jill M Williamson
- Centre for Discovery Brain Sciences, University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Jason J Early
- Centre for Discovery Brain Sciences, University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Tim Czopka
- Centre for Discovery Brain Sciences, University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK; Institute of Neuronal Cell Biology, Technical University of Munich, Biedersteiner Strasse 29, 80802 Munich, Germany; Munich Cluster of Systems Neurology (SyNergy), Feodor-Lynen Strasse 17, 81377 Munich, Germany
| | - Anna Klingseisen
- Centre for Discovery Brain Sciences, University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Jonah R Chan
- Department of Neurology and Program in Neuroscience, University of California, San Francisco, 675 Nelson Rising Lane, San Francisco, CA 94143, USA
| | - David A Lyons
- Centre for Discovery Brain Sciences, University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK.
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