1
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Gao R, Song SJ, Tian MY, Wang LB, Zhang Y, Li X. Myelin debris phagocytosis in demyelinating disease. Glia 2024. [PMID: 39073200 DOI: 10.1002/glia.24602] [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: 12/26/2023] [Revised: 07/16/2024] [Accepted: 07/18/2024] [Indexed: 07/30/2024]
Abstract
Demyelinating diseases are often caused by a variety of triggers, including immune responses, viral infections, malnutrition, hypoxia, or genetic factors, all of which result in the loss of myelin in the nervous system. The accumulation of myelin debris at the lesion site leads to neuroinflammation and inhibits remyelination; therefore, it is crucial to promptly remove the myelin debris. Initially, Fc and complement receptors on cellular surfaces were the primary clearance receptors responsible for removing myelin debris. However, subsequent studies have unveiled the involvement of additional receptors, including Mac-2, TAM receptors, and the low-density lipoprotein receptor-related protein 1, in facilitating the removal process. In addition to microglia and macrophages, which serve as the primary effector cells in the disease phase, a variety of other cell types such as astrocytes, Schwann cells, and vascular endothelial cells have been demonstrated to engage in the phagocytosis of myelin debris. Furthermore, we have concluded that oligodendrocyte precursor cells, as myelination precursor cells, also exhibit this phagocytic capability. Moreover, our research group has innovatively identified the low-density lipoprotein receptor as a potential phagocytic receptor for myelin debris. In this article, we discuss the functional processes of various phagocytes in demyelinating diseases. We also highlight the alterations in signaling pathways triggered by phagocytosis, and provide a comprehensive overview of the various phagocytic receptors involved. Such insights are invaluable for pinpointing potential therapeutic strategies for the treatment of demyelinating diseases by targeting phagocytosis.
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Affiliation(s)
- Rui Gao
- The Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi, China
| | - Sheng-Jiao Song
- The Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi, China
| | - Meng-Yuan Tian
- The Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi, China
| | - Li-Bin Wang
- Neurosurgery Department, Huazhong University of Science and Technology Union Shenzhen Hospital/Shenzhen Nanshan Hospital, Shenzhen, Guangdong, China
| | - Yuan Zhang
- The Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi, China
| | - Xing Li
- The Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi, China
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2
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Kawade N, Yamanaka K. Novel insights into brain lipid metabolism in Alzheimer's disease: Oligodendrocytes and white matter abnormalities. FEBS Open Bio 2024; 14:194-216. [PMID: 37330425 PMCID: PMC10839347 DOI: 10.1002/2211-5463.13661] [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: 05/10/2023] [Revised: 06/07/2023] [Accepted: 06/14/2023] [Indexed: 06/19/2023] Open
Abstract
Alzheimer's disease (AD) is the most common cause of dementia. A genome-wide association study has shown that several AD risk genes are involved in lipid metabolism. Additionally, epidemiological studies have indicated that the levels of several lipid species are altered in the AD brain. Therefore, lipid metabolism is likely changed in the AD brain, and these alterations might be associated with an exacerbation of AD pathology. Oligodendrocytes are glial cells that produce the myelin sheath, which is a lipid-rich insulator. Dysfunctions of the myelin sheath have been linked to white matter abnormalities observed in the AD brain. Here, we review the lipid composition and metabolism in the brain and myelin and the association between lipidic alterations and AD pathology. We also present the abnormalities in oligodendrocyte lineage cells and white matter observed in AD. Additionally, we discuss metabolic disorders, including obesity, as AD risk factors and the effects of obesity and dietary intake of lipids on the brain.
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Affiliation(s)
- Noe Kawade
- Department of Neuroscience and Pathobiology, Research Institute of Environmental MedicineNagoya UniversityJapan
- Department of Neuroscience and Pathobiology, Nagoya University Graduate School of MedicineNagoya UniversityJapan
| | - Koji Yamanaka
- Department of Neuroscience and Pathobiology, Research Institute of Environmental MedicineNagoya UniversityJapan
- Department of Neuroscience and Pathobiology, Nagoya University Graduate School of MedicineNagoya UniversityJapan
- Institute for Glyco‐core Research (iGCORE)Nagoya UniversityJapan
- Center for One Medicine Innovative Translational Research (COMIT)Nagoya UniversityJapan
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3
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Kozlenkov A, Vadukapuram R, Zhou P, Fam P, Wegner M, Dracheva S. Novel method of isolating nuclei of human oligodendrocyte precursor cells reveals substantial developmental changes in gene expression and H3K27ac histone modification. Glia 2024; 72:69-89. [PMID: 37712493 PMCID: PMC10697634 DOI: 10.1002/glia.24462] [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: 09/18/2022] [Revised: 08/01/2023] [Accepted: 08/09/2023] [Indexed: 09/16/2023]
Abstract
Oligodendrocyte precursor cells (OPCs) generate differentiated mature oligodendrocytes (MOs) during development. In adult brain, OPCs replenish MOs in adaptive plasticity, neurodegenerative disorders, and after trauma. The ability of OPCs to differentiate to MOs decreases with age and is compromised in disease. Here we explored the cell specific and age-dependent differences in gene expression and H3K27ac histone mark in these two cell types. H3K27ac is indicative of active promoters and enhancers. We developed a novel flow-cytometry-based approach to isolate OPC and MO nuclei from human postmortem brain and profiled gene expression and H3K27ac in adult and infant OPCs and MOs genome-wide. In adult brain, we detected extensive H3K27ac differences between the two cell types with high concordance between gene expression and epigenetic changes. Notably, the expression of genes that distinguish MOs from OPCs appears to be under a strong regulatory control by the H3K27ac modification in MOs but not in OPCs. Comparison of gene expression and H3K27ac between infants and adults uncovered numerous developmental changes in each cell type, which were linked to several biological processes, including cell proliferation and glutamate signaling. A striking example was a subset of histone genes that were highly active in infant samples but fully lost activity in adult brain. Our findings demonstrate a considerable rearrangement of the H3K27ac landscape that occurs during the differentiation of OPCs to MOs and during postnatal development of these cell types, which aligned with changes in gene expression. The uncovered regulatory changes justify further in-depth epigenetic studies of OPCs and MOs in development and disease.
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Affiliation(s)
- Alexey Kozlenkov
- James J. Peters VA Medical Center, Bronx, NY, USA
- Friedman Brain Institute and Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Ramu Vadukapuram
- James J. Peters VA Medical Center, Bronx, NY, USA
- Friedman Brain Institute and Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Ping Zhou
- James J. Peters VA Medical Center, Bronx, NY, USA
- Friedman Brain Institute and Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Peter Fam
- James J. Peters VA Medical Center, Bronx, NY, USA
| | - Michael Wegner
- Institut für Biochemie, Emil-Fischer-Zentrum, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Stella Dracheva
- James J. Peters VA Medical Center, Bronx, NY, USA
- Friedman Brain Institute and Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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4
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Gould R, Brady S. Identifying mRNAs Residing in Myelinating Oligodendrocyte Processes as a Basis for Understanding Internode Autonomy. Life (Basel) 2023; 13:945. [PMID: 37109474 PMCID: PMC10142070 DOI: 10.3390/life13040945] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 03/28/2023] [Accepted: 03/31/2023] [Indexed: 04/07/2023] Open
Abstract
In elaborating and maintaining myelin sheaths on multiple axons/segments, oligodendrocytes distribute translation of some proteins, including myelin basic protein (MBP), to sites of myelin sheath assembly, or MSAS. As mRNAs located at these sites are selectively trapped in myelin vesicles during tissue homogenization, we performed a screen to identify some of these mRNAs. To confirm locations, we used real-time quantitative polymerase chain reaction (RT-qPCR), to measure mRNA levels in myelin (M) and 'non-myelin' pellet (P) fractions, and found that five (LPAR1, TRP53INP2, TRAK2, TPPP, and SH3GL3) of thirteen mRNAs were highly enriched in myelin (M/P), suggesting residences in MSAS. Because expression by other cell-types will increase p-values, some MSAS mRNAs might be missed. To identify non-oligodendrocyte expression, we turned to several on-line resources. Although neurons express TRP53INP2, TRAK2 and TPPP mRNAs, these expressions did not invalidate recognitions as MSAS mRNAs. However, neuronal expression likely prevented recognition of KIF1A and MAPK8IP1 mRNAs as MSAS residents and ependymal cell expression likely prevented APOD mRNA assignment to MSAS. Complementary in situ hybridization (ISH) is recommended to confirm residences of mRNAs in MSAS. As both proteins and lipids are synthesized in MSAS, understanding myelination should not only include efforts to identify proteins synthesized in MSAS, but also the lipids.
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Affiliation(s)
- Robert Gould
- Whitman Research Center, Marine Biology Laboratory, Woods Hole, MA 02543, USA
| | - Scott Brady
- Departments of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612, USA;
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5
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Graciani AL, Gutierre MU, Coppi AA, Arida RM, Gutierre RC. MYELIN, AGING, AND PHYSICAL EXERCISE. Neurobiol Aging 2023; 127:70-81. [PMID: 37116408 DOI: 10.1016/j.neurobiolaging.2023.03.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/22/2023] [Accepted: 03/24/2023] [Indexed: 04/03/2023]
Abstract
Myelin sheath is a structure in neurons fabricated by oligodendrocytes and Schwann cells responsible for increasing the efficiency of neural synapsis, impulse transmission, and providing metabolic support to the axon. They present morpho-functional changes during health aging as deformities of the sheath and its fragmentation, causing an increased load on microglial phagocytosis, with Alzheimer's disease aggravating. Physical exercise has been studied as a possible protective agent for the nervous system, offering benefits to neuroplasticity. In this regard, studies in animal models for Alzheimer's and depression reported the efficiency of physical exercise in protecting against myelin degeneration. A reduction of myelin damage during aging has also been observed in healthy humans. Physical activity promotes oligodendrocyte proliferation and myelin preservation during old age, although some controversies remain. In this review, we will address how effective physical exercise can be as a protective agent of the myelin sheath against the effects of aging in physiological and pathological conditions.
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6
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Barnes-Vélez JA, Aksoy Yasar FB, Hu J. Myelin lipid metabolism and its role in myelination and myelin maintenance. Innovation (N Y) 2023; 4:100360. [PMID: 36588745 PMCID: PMC9800635 DOI: 10.1016/j.xinn.2022.100360] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 12/03/2022] [Indexed: 12/12/2022] Open
Abstract
Myelin is a specialized cell membrane indispensable for rapid nerve conduction. The high abundance of membrane lipids is one of myelin's salient features that contribute to its unique role as an insulator that electrically isolates nerve fibers across their myelinated surface. The most abundant lipids in myelin include cholesterol, glycosphingolipids, and plasmalogens, each playing critical roles in myelin development as well as function. This review serves to summarize the role of lipid metabolism in myelination and myelin maintenance, as well as the molecular determinants of myelin lipid homeostasis, with an emphasis on findings from genetic models. In addition, the implications of myelin lipid dysmetabolism in human diseases are highlighted in the context of hereditary leukodystrophies and neuropathies as well as acquired disorders such as Alzheimer's disease.
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Affiliation(s)
- Joseph A. Barnes-Vélez
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77054-1901, USA
- MD Anderson Cancer Center UTHealth Graduate School of Biomedical Science, Houston, TX 77225-0334, USA
- University of Puerto Rico Medical Sciences Campus, School of Medicine, San Juan, PR 00936-5067, USA
| | - Fatma Betul Aksoy Yasar
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77054-1901, USA
- MD Anderson Cancer Center UTHealth Graduate School of Biomedical Science, Houston, TX 77225-0334, USA
| | - Jian Hu
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77054-1901, USA
- MD Anderson Cancer Center UTHealth Graduate School of Biomedical Science, Houston, TX 77225-0334, USA
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7
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Błażewicz A, Grabrucker AM. Metal Profiles in Autism Spectrum Disorders: A Crosstalk between Toxic and Essential Metals. Int J Mol Sci 2022; 24:ijms24010308. [PMID: 36613749 PMCID: PMC9820494 DOI: 10.3390/ijms24010308] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/15/2022] [Accepted: 12/21/2022] [Indexed: 12/28/2022] Open
Abstract
Since hundreds of years ago, metals have been recognized as impacting our body's physiology. As a result, they have been studied as a potential cure for many ailments as well as a cause of acute or chronic poisoning. However, the link between aberrant metal levels and neuropsychiatric illnesses such as schizophrenia and neurodevelopmental disorders, such as autism spectrum disorders (ASDs), is a relatively new finding, despite some evident ASD-related consequences of shortage or excess of specific metals. In this review, we will summarize past and current results explaining the pathomechanisms of toxic metals at the cellular and molecular levels that are still not fully understood. While toxic metals may interfere with dozens of physiological processes concurrently, we will focus on ASD-relevant activity such as inflammation/immune activation, mitochondrial malfunction, increased oxidative stress, impairment of axonal myelination, and synapse formation and function. In particular, we will highlight the competition with essential metals that may explain why both the presence of certain toxic metals and the absence of certain essential metals have emerged as risk factors for ASD. Although often investigated separately, through the agonistic and antagonistic effects of metals, a common metal imbalance may result in relation to ASD.
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Affiliation(s)
- Anna Błażewicz
- Department of Pathobiochemistry and Interdisciplinary Applications of Ion Chromatography, Medical University of Lublin, 20-093 Lublin, Poland
| | - Andreas M. Grabrucker
- Department of Biological Sciences, University of Limerick, V94 T9PX Limerick, Ireland
- Bernal Institute, University of Limerick, V94 T9PX Limerick, Ireland
- Health Research Institute (HRI), University of Limerick, V94 T9PX Limerick, Ireland
- Correspondence: ; Tel.: +353-61-237756
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8
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Meschkat M, Steyer AM, Weil MT, Kusch K, Jahn O, Piepkorn L, Agüi-Gonzalez P, Phan NTN, Ruhwedel T, Sadowski B, Rizzoli SO, Werner HB, Ehrenreich H, Nave KA, Möbius W. White matter integrity in mice requires continuous myelin synthesis at the inner tongue. Nat Commun 2022; 13:1163. [PMID: 35246535 PMCID: PMC8897471 DOI: 10.1038/s41467-022-28720-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 01/24/2022] [Indexed: 12/18/2022] Open
Abstract
Myelin, the electrically insulating sheath on axons, undergoes dynamic changes over time. However, it is composed of proteins with long lifetimes. This raises the question how such a stable structure is renewed. Here, we study the integrity of myelinated tracts after experimentally preventing the formation of new myelin in the CNS of adult mice, using an inducible Mbp null allele. Oligodendrocytes survive recombination, continue to express myelin genes, but they fail to maintain compacted myelin sheaths. Using 3D electron microscopy and mass spectrometry imaging we visualize myelin-like membranes failing to incorporate adaxonally, most prominently at juxta-paranodes. Myelinoid body formation indicates degradation of existing myelin at the abaxonal side and the inner tongue of the sheath. Thinning of compact myelin and shortening of internodes result in the loss of about 50% of myelin and axonal pathology within 20 weeks post recombination. In summary, our data suggest that functional axon-myelin units require the continuous incorporation of new myelin membranes. Myelin is formed of proteins of long half-lives. The mechanisms of renewal of such a stable structure are unclear. Here, the authors show that myelin integrity requires continuous myelin synthesis at the inner tongue, contributing to the maintenance of a functional axon-myelin unit.
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Affiliation(s)
- Martin Meschkat
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Electron Microscopy Core Unit, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Göttingen Graduate Center for Neurosciences, Biophysics, and Molecular Biosciences (GGNB), Göttingen, Germany.,DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany.,Abberior Instruments GmbH, Göttingen, Germany
| | - Anna M Steyer
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Electron Microscopy Core Unit, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany.,Imaging Centre, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Marie-Theres Weil
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Electron Microscopy Core Unit, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Kathrin Kusch
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Olaf Jahn
- DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany.,Proteomics Group, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Translational Neuroproteomics Group, Department of Psychiatry and Psychotherapy, University Medical Center Göttingen, Göttingen, Germany
| | - Lars Piepkorn
- Proteomics Group, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Translational Neuroproteomics Group, Department of Psychiatry and Psychotherapy, University Medical Center Göttingen, Göttingen, Germany
| | - Paola Agüi-Gonzalez
- Department of Neuro- and Sensory Physiology, University Medical Center Göttingen, Center for Biostructural Imaging of Neurodegeneration, Göttingen, Germany
| | - Nhu Thi Ngoc Phan
- Department of Neuro- and Sensory Physiology, University Medical Center Göttingen, Center for Biostructural Imaging of Neurodegeneration, Göttingen, Germany.,Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Torben Ruhwedel
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Electron Microscopy Core Unit, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Boguslawa Sadowski
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Electron Microscopy Core Unit, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Silvio O Rizzoli
- DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany.,Department of Neuro- and Sensory Physiology, University Medical Center Göttingen, Center for Biostructural Imaging of Neurodegeneration, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Hannelore Ehrenreich
- DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany.,Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany. .,Electron Microscopy Core Unit, Max Planck Institute of Experimental Medicine, Göttingen, Germany. .,DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany. .,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany.
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9
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Wu X, Ya J, Zhou D, Ding Y, Ji X, Meng R. Pathogeneses and Imaging Features of Cerebral White Matter Lesions of Vascular Origins. Aging Dis 2021; 12:2031-2051. [PMID: 34881084 PMCID: PMC8612616 DOI: 10.14336/ad.2021.0414] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 04/14/2021] [Indexed: 01/10/2023] Open
Abstract
White matter lesion (WML), also known as white matter hyperintensities or leukoaraiosis, was first termed in 1986 to describe the hyperintense signals on T2-weighted imaging (T2WI) and fluid-attenuated inversion recovery (FLAIR) maps. Over the past decades, a growing body of pathophysiological findings regarding WMLs have been discovered and discussed. Currently, the generally accepted WML pathogeneses mainly include hypoxia-ischemia, endothelial dysfunction, blood-brain barrier disruption, and infiltration of inflammatory mediators or cytokines. However, none of them can explain the whole dynamics of WML formation. Herein, we primarily focus on the pathogeneses and neuroimaging features of vascular WMLs. To achieve this goal, we searched papers with any type published in PubMed from 1950 to 2020 and cross-referenced the keywords including “leukoencephalopathy”, “leukoaraiosis”, “white matter hyperintensity”, “white matter lesion”, “pathogenesis”, “pathology”, “pathophysiology”, and “neuroimaging”. Moreover, references of the selected articles were browsed and searched for additional pertinent articles. We believe this work will supply the robust references for clinicians to further understand the different WML patterns of varying vascular etiologies and thus make customized treatment.
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Affiliation(s)
- Xiaoqin Wu
- 1Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.,2Advanced Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China.,3Department of China-America Institute of Neuroscience, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Jingyuan Ya
- 1Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.,2Advanced Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China.,3Department of China-America Institute of Neuroscience, Xuanwu Hospital, Capital Medical University, Beijing, China.,4Division of Clinical Neuroscience, Queen's Medical Center School of Medicine, the University of Nottingham, Nottingham NG7 2UH, UK
| | - Da Zhou
- 1Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.,2Advanced Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China.,3Department of China-America Institute of Neuroscience, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yuchuan Ding
- 3Department of China-America Institute of Neuroscience, Xuanwu Hospital, Capital Medical University, Beijing, China.,5Department of Neurosurgery, Wayne State University School of Medicine, Detroit, Michigan 48201, USA
| | - Xunming Ji
- 1Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.,2Advanced Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China.,3Department of China-America Institute of Neuroscience, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Ran Meng
- 1Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.,2Advanced Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China.,3Department of China-America Institute of Neuroscience, Xuanwu Hospital, Capital Medical University, Beijing, China
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10
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Hoffmann M, Haselberger D, Hofmann T, Müller L, Janson K, Meister A, Das M, Vargas C, Keller S, Kastritis PL, Schmidt C, Hinderberger D. Nanoscale Model System for the Human Myelin Sheath. Biomacromolecules 2021; 22:3901-3912. [PMID: 34324309 DOI: 10.1021/acs.biomac.1c00714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Neurodegenerative disorders are among the most common diseases in modern society. However, the molecular bases of diseases such as multiple sclerosis or Charcot-Marie-Tooth disease remain far from being fully understood. Research in this field is limited by the complex nature of native myelin and by difficulties in obtaining good in vitro model systems of myelin. Here, we introduce an easy-to-use model system of the myelin sheath that can be used to study myelin proteins in a native-like yet well-controlled environment. To this end, we present myelin-mimicking nanodiscs prepared through one of the amphiphilic copolymers styrene/maleic acid (SMA), diisobutylene/maleic acid (DIBMA), and styrene/maleimide sulfobetaine (SMA-SB). These nanodiscs were tested for their lipid composition using chromatographic (HPLC) and mass spectrometric (MS) methods and, utilizing spin probes within the nanodisc, their comparability with liposomes was studied. In addition, their binding behavior with bovine myelin basic protein (MBP) was scrutinized to ensure that the nanodiscs represent a suitable model system of myelin. Our results suggest that both SMA and SMA-SB are able to solubilize the myelin-like (cytoplasmic) liposomes without preferences for specific lipid headgroups or fatty acyl chains. In nanodiscs of both SMA and SMA-SB (called SMA(-SB)-lipid particles, short SMALPs or SMA-SBLPs, respectively), the polymers restrict the lipids' motion in the hydrophobic center of the bilayer. The headgroups of the lipids, however, are sterically less hindered in nanodiscs when compared with liposomes. Myelin-like SMALPs are able to bind bovine MBP, which can stack the lipid bilayers like in native myelin, showing the usability of these simple, well-controlled systems in further studies of protein-lipid interactions of native myelin.
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Affiliation(s)
- Matthias Hoffmann
- Interdisciplinary Research Center HALOmem, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany.,Institute of Chemistry, Martin Luther University (MLU) Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - David Haselberger
- Interdisciplinary Research Center HALOmem, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany.,Institute of Chemistry, Martin Luther University (MLU) Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - Tommy Hofmann
- Interdisciplinary Research Center HALOmem, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany.,Institute of Biochemistry and Biotechnology, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany
| | - Lisa Müller
- Institute of Pharmacy, Martin Luther University (MLU) Halle-Wittenberg, Wolfgang-Langenbeck-Straße 4, 06120 Halle (Saale), Germany
| | - Kevin Janson
- Interdisciplinary Research Center HALOmem, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany.,Institute of Biochemistry and Biotechnology, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany
| | - Annette Meister
- Interdisciplinary Research Center HALOmem, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany.,Institute of Biochemistry and Biotechnology, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany
| | - Manabendra Das
- Molecular Biophysics, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Straße 13, 67663 Kaiserslautern, Germany
| | - Carolyn Vargas
- Molecular Biophysics, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Straße 13, 67663 Kaiserslautern, Germany.,Biophysics, Institute of Molecular Biosciences (IMB), NAWI Graz, University of Graz, Humboldtstraße 50/III, 8010 Graz, Austria.,Field of Excellence BioHealth, University of Graz, 8010 Graz, Austria.,BioTechMed-Graz, 8010 Graz, Austria
| | - Sandro Keller
- Molecular Biophysics, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Straße 13, 67663 Kaiserslautern, Germany.,Biophysics, Institute of Molecular Biosciences (IMB), NAWI Graz, University of Graz, Humboldtstraße 50/III, 8010 Graz, Austria.,Field of Excellence BioHealth, University of Graz, 8010 Graz, Austria.,BioTechMed-Graz, 8010 Graz, Austria
| | - Panagiotis L Kastritis
- Interdisciplinary Research Center HALOmem, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany.,Institute of Biochemistry and Biotechnology, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany
| | - Carla Schmidt
- Interdisciplinary Research Center HALOmem, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany.,Institute of Biochemistry and Biotechnology, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany
| | - Dariush Hinderberger
- Interdisciplinary Research Center HALOmem, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany.,Institute of Chemistry, Martin Luther University (MLU) Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
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11
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Tripathi M, Sreedharan Thankarajan AR, Tripathi M, Garg A, Ramanujam B, Snigdha, Bal C. F-18 Fluorodeoxyglucose Positron Emission Tomography Metabolic Phenotype in Myelin Oligodendrocyte Glycoprotein Antibody-Positive Autoimmune Epilepsy. Indian J Nucl Med 2021; 36:88-89. [PMID: 34040310 PMCID: PMC8130699 DOI: 10.4103/ijnm.ijnm_167_20] [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: 07/23/2020] [Revised: 08/20/2020] [Accepted: 09/11/2020] [Indexed: 11/10/2022] Open
Abstract
We describe the metabolic phenotype on F-18 fluorodeoxyglucose positron emission tomography (PET) in a 13-year-old female with myelin oligodendrocyte glycoprotein (MOG) antibody–positive encephalitis. Unilateral hemispheric hypometabolism on PET may be the metabolic phenotype of autoimmune epilepsy associated with MOG antibody.
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Affiliation(s)
- Madhavi Tripathi
- Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India
| | | | - Manjari Tripathi
- Department of Neurology, Cardiothoracic and Neurosciences Centre, All India Institute of Medical Sciences, New Delhi, India
| | - Ajay Garg
- Department of Neuroradiology, Cardiothoracic and Neurosciences Centre, All India Institute of Medical Sciences, New Delhi, India
| | - Bhargavi Ramanujam
- Department of Neurology, Cardiothoracic and Neurosciences Centre, All India Institute of Medical Sciences, New Delhi, India
| | - Snigdha
- Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India
| | - Chandrasekhar Bal
- Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India
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12
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Rajani RM, Dupré N, Domenga-Denier V, Van Niel G, Heiligenstein X, Joutel A. Characterisation of early ultrastructural changes in the cerebral white matter of CADASIL small vessel disease using high-pressure freezing/freeze-substitution. Neuropathol Appl Neurobiol 2021; 47:694-704. [PMID: 33483954 DOI: 10.1111/nan.12697] [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: 10/30/2020] [Revised: 01/08/2021] [Accepted: 01/15/2021] [Indexed: 11/29/2022]
Abstract
AIMS The objective of this study was to elucidate the early white matter changes in CADASIL small vessel disease. METHODS We used high-pressure freezing and freeze substitution (HPF/FS) in combination with high-resolution electron microscopy (EM), immunohistochemistry and confocal microscopy of brain specimens from control and CADASIL (TgNotch3R169C ) mice aged 4-15 months to study white matter lesions in the corpus callosum. RESULTS We first optimised the HPF/FS protocol in which samples were chemically prefixed, frozen in a sample carrier filled with 20% polyvinylpyrrolidone and freeze-substituted in a cocktail of tannic acid, osmium tetroxide and uranyl acetate dissolved in acetone. EM analysis showed that CADASIL mice exhibit significant splitting of myelin layers and enlargement of the inner tongue of small calibre axons from the age of 6 months, then vesiculation of the inner tongue and myelin sheath thinning at 15 months of age. Immunohistochemistry revealed an increased number of oligodendrocyte precursor cells, although only in older mice, but no reduction in the number of mature oligodendrocytes at any age. The number of Iba1 positive microglial cells was increased in older but not in younger CADASIL mice, but the number of activated microglial cells (Iba1 and CD68 positive) was unchanged at any age. CONCLUSION We conclude that early WM lesions in CADASIL affect first and foremost the myelin sheath and the inner tongue, suggestive of a primary myelin injury. We propose that those defects are consistent with a hypoxic/ischaemic mechanism.
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Affiliation(s)
- Rikesh M Rajani
- Institute of Psychiatry and Neurosciences of Paris, Inserm U1266, Université de Paris, Paris, France
| | - Nicolas Dupré
- Institute of Psychiatry and Neurosciences of Paris, Inserm U1266, Université de Paris, Paris, France
| | - Valérie Domenga-Denier
- Institute of Psychiatry and Neurosciences of Paris, Inserm U1266, Université de Paris, Paris, France
| | - Guillaume Van Niel
- Institute of Psychiatry and Neurosciences of Paris, Inserm U1266, Université de Paris, Paris, France.,GHU Paris Psychiatrie et Neurosciences, Hôpital Sainte Anne, Paris, France
| | | | - Anne Joutel
- Institute of Psychiatry and Neurosciences of Paris, Inserm U1266, Université de Paris, Paris, France.,GHU Paris Psychiatrie et Neurosciences, Hôpital Sainte Anne, Paris, France.,Department of Pharmacology, College of Medicine, University of Vermont, Burlington, VT, USA
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13
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Membrane stiffness and myelin basic protein binding strength as molecular origin of multiple sclerosis. Sci Rep 2020; 10:16691. [PMID: 33028889 PMCID: PMC7542173 DOI: 10.1038/s41598-020-73671-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 09/21/2020] [Indexed: 01/08/2023] Open
Abstract
Myelin basic protein (MBP) and its interaction with lipids of the myelin sheath plays an important part in the pathology of multiple sclerosis (MS). Previous studies observed that changes in the myelin lipid composition lead to instabilities and enhanced local curvature of MBP-lipid multilayer structures. We investigated the molecular origin of the instability and found that the diseased lipid membrane has a 25% lower bending rigidity, thus destabilizing smooth \documentclass[12pt]{minimal}
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\begin{document}$$>1\,$$\end{document}>1µm curvature radius structures such as in giant unilamellar vesicles. MBP-mediated assembling of lipid bilayers proceeds in two steps, with a slow second step occurring over many days where native lipid membranes assemble into well-defined multilayer structures, whereas diseased lipid membranes form folded assemblies with high local curvature. For both native and diseased lipid mixtures we find that MBP forms dense liquid phases on top of the lipid membranes mediating attractive membrane interactions. Furthermore, we observe MBP to insert into its bilayer leaflet side in case of the diseased lipid mixture, whereas there is no insertion for the native mixture. Insertion increases the local membrane curvature, and could be caused by a decrease of the sphingomyelin content of the diseased lipid mixture. These findings can help to open a pathway to remyelination strategies.
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14
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Yoo SW, Agarwal A, Smith MD, Khuder SS, Baxi EG, Thomas AG, Rojas C, Moniruzzaman M, Slusher BS, Bergles DE, Calabresi PA, Haughey NJ. Inhibition of neutral sphingomyelinase 2 promotes remyelination. SCIENCE ADVANCES 2020; 6:6/40/eaba5210. [PMID: 33008902 PMCID: PMC7852391 DOI: 10.1126/sciadv.aba5210] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Accepted: 08/20/2020] [Indexed: 05/05/2023]
Abstract
Myelination requires a highly organized synthesis of multiple lipid species that regulate myelin curvature and compaction. For reasons that are not understood, central nervous system remyelinated axons often have thin myelin sheaths with a disorganized structure susceptible to secondary demyelination. We found that expression of the sphingomyelin hydrolase neutral sphingomyelinase 2 (nSMase2) during the differentiation of oligodendrocyte progenitor cells (OPCs) to myelinating oligodendrocytes changes their response to inflammatory cytokines. OPCs do not express nSMase2 and exhibit a protective/regenerative response to tumor necrosis factor-α and interleukin-1β. Oligodendrocytes express nSMase2 and exhibit a stress response to cytokine challenge that includes an overproduction of ceramide, a sphingolipid that forms negative curvatures in membranes. Pharmacological inhibition or genetic deletion of nSMase2 in myelinating oligodendrocytes normalized the ceramide content of remyelinated fibers and increased thickness and compaction. These results suggest that inhibition of nSMase2 could improve the quality of myelin and stabilize structure.
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Affiliation(s)
- Seung-Wan Yoo
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Amit Agarwal
- The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Matthew D Smith
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Saja S Khuder
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Emily G Baxi
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Ajit G Thomas
- The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Camilo Rojas
- Department of Comparative Medicine and Pathobiology, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Mohammed Moniruzzaman
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Barbara S Slusher
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Department of Comparative Medicine and Pathobiology, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Department of Psychiatry, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Dwight E Bergles
- The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Johns Hopkins University Kavli Neuroscience Discovery Institute, Baltimore, MD 21287, USA
| | - Peter A Calabresi
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Norman J Haughey
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
- Department of Psychiatry, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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15
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Abstract
Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system. We review the two core MS features, myelin instability, fragmentation, and remyelination failure, and dominance of pathogenic CD4+ Th17 cells over protective CD4+ Treg cells. To better understand myelin pathology, we describe myelin biosynthesis, structure, and function, then highlight stearoyl-CoA desaturase (SCD) in nervonic acid biosynthesis and nervonic acid's contribution to myelin stability. Noting that vitamin D deficiency decreases SCD in the periphery, we propose it also decreases SCD in oligodendrocytes, disrupting the nervonic acid supply and causing myelin instability and fragmentation. To better understand the distorted Th17/Treg cell balance, we summarize Th17 cell contributions to MS pathogenesis, then highlight how 1,25-dihydroxyvitamin D3 signaling from microglia to CD4+ T cells restores Treg cell dominance. This signaling rapidly increases flux through the methionine cycle, removing homocysteine, replenishing S-adenosyl-methionine, and improving epigenetic marking. Noting that DNA hypomethylation and inappropriate DRB1*1501 expression were observed in MS patient CD4+ T cells, we propose that vitamin D deficiency thwarts epigenetic downregulation of DRB1*1501 and Th17 cell signature genes, and upregulation of Treg cell signature genes, causing dysregulation within the CD4+ T cell compartment. We explain how obesity reduces vitamin D status, and how estrogen and vitamin D collaborate to promote Treg cell dominance in females. Finally, we discuss the implications of this new knowledge concerning myelin and the Th17/Treg cell balance, and advocate for efforts to address the global epidemics of obesity and vitamin D deficiency in the expectation of reducing the impact of MS.
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Affiliation(s)
- Colleen E. Hayes
- Department of Biochemistry, College of Agricultural and Life Sciences, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706, USA
| | - James M. Ntambi
- Department of Biochemistry, College of Agricultural and Life Sciences, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706, USA
- Department of Nutritional Sciences, University of Wisconsin-Madison, 1415 Linden Drive, Madison, WI 53706, USA
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16
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Poitelon Y, Kopec AM, Belin S. Myelin Fat Facts: An Overview of Lipids and Fatty Acid Metabolism. Cells 2020; 9:cells9040812. [PMID: 32230947 PMCID: PMC7226731 DOI: 10.3390/cells9040812] [Citation(s) in RCA: 156] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 03/24/2020] [Accepted: 03/25/2020] [Indexed: 12/11/2022] Open
Abstract
Myelin is critical for the proper function of the nervous system and one of the most complex cell–cell interactions of the body. Myelination allows for the rapid conduction of action potentials along axonal fibers and provides physical and trophic support to neurons. Myelin contains a high content of lipids, and the formation of the myelin sheath requires high levels of fatty acid and lipid synthesis, together with uptake of extracellular fatty acids. Recent studies have further advanced our understanding of the metabolism and functions of myelin fatty acids and lipids. In this review, we present an overview of the basic biology of myelin lipids and recent insights on the regulation of fatty acid metabolism and functions in myelinating cells. In addition, this review may serve to provide a foundation for future research characterizing the role of fatty acids and lipids in myelin biology and metabolic disorders affecting the central and peripheral nervous system.
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17
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Hoch-Kraft P, Trotter J, Gonsior C. Missing in Action: Dysfunctional RNA Metabolism in Oligodendroglial Cells as a Contributor to Neurodegenerative Diseases? Neurochem Res 2019; 45:566-579. [PMID: 30843138 DOI: 10.1007/s11064-019-02763-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 02/22/2019] [Accepted: 02/23/2019] [Indexed: 12/14/2022]
Abstract
The formation of myelin around axons by oligodendrocytes (OL) poses an enormous synthetic and energy challenge for the glial cell. Local translation of transcripts, including the mRNA for the essential myelin protein Myelin Basic Protein (MBP) at the site of myelin deposition has been recognised as an efficient mechanism to assure proper myelin sheath assembly. Oligodendroglial precursor cells (OPCs) form synapses with neurons and may localise many additional mRNAs in a similar fashion to synapses between neurons. In some diseases in which demyelination occurs, an abundance of OPCs is present but there is a failure to efficiently remyelinate and to synthesise MBP. This compromises axonal survival and function. OPCs are especially sensitive to cellular stress as occurring in neurodegenerative diseases, which can impinge on their ability to translate mRNAs into protein. Stress causes the build up of cytoplasmic stress granules (SG) in which many RNAs are sequestered and translationally stalled until the stress ceases. Chronic stress in particular could convert this initially protective reaction of the cell into damage, as persistence of SG may lead to pathological aggregate formation or long-term translation block of SG-associated RNAs. The recent recognition that many neurodegenerative diseases often exhibit an early white matter pathology with a proliferation of surviving OPCs, renders a study of the stress-associated processes in oligodendrocytes and OPCs especially relevant. Here, we discuss a potential dysfunction of RNA regulation in myelin diseases such as Multiple Sclerosis (MS) and Vanishing white matter disease (VWM) and potential contributions of OL dysfunction to neurodegenerative diseases such as Amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD) and Fragile X syndrome (FXS).
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Affiliation(s)
- Peter Hoch-Kraft
- Cellular Neurobiology, Institute for Developmental Biology and Neurobiology, Johannes Gutenberg-University of Mainz, Anselm-Franz-von-Bentzelweg 3, 55128, Mainz, Germany
| | - Jacqueline Trotter
- Cellular Neurobiology, Institute for Developmental Biology and Neurobiology, Johannes Gutenberg-University of Mainz, Anselm-Franz-von-Bentzelweg 3, 55128, Mainz, Germany
| | - Constantin Gonsior
- Cellular Neurobiology, Institute for Developmental Biology and Neurobiology, Johannes Gutenberg-University of Mainz, Anselm-Franz-von-Bentzelweg 3, 55128, Mainz, Germany.
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18
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Truong PH, Ciccotosto GD, Merson TD, Spoerri L, Chuei MJ, Ayers M, Xing YL, Emery B, Cappai R. Amyloid precursor protein and amyloid precursor-like protein 2 have distinct roles in modulating myelination, demyelination, and remyelination of axons. Glia 2018; 67:525-538. [DOI: 10.1002/glia.23561] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 10/18/2018] [Accepted: 10/19/2018] [Indexed: 12/14/2022]
Affiliation(s)
- Phan H. Truong
- Department of Pathology; The University of Melbourne; Melbourne Victoria Australia
- The Bio21 Molecular Science and Biotechnology Institute; The University of Melbourne; Melbourne Victoria Australia
- Department of Pharmacology and Therapeutics; The University of Melbourne; Melbourne Victoria Australia
| | - Giuseppe D. Ciccotosto
- Department of Pathology; The University of Melbourne; Melbourne Victoria Australia
- The Bio21 Molecular Science and Biotechnology Institute; The University of Melbourne; Melbourne Victoria Australia
- Department of Pharmacology and Therapeutics; The University of Melbourne; Melbourne Victoria Australia
| | - Tobias D. Merson
- The Florey Institute of Neuroscience and Mental Health; The University of Melbourne; Melbourne Victoria Australia
| | - Loredana Spoerri
- Department of Pathology; The University of Melbourne; Melbourne Victoria Australia
- The Bio21 Molecular Science and Biotechnology Institute; The University of Melbourne; Melbourne Victoria Australia
| | - Mun Joo Chuei
- Department of Pathology; The University of Melbourne; Melbourne Victoria Australia
- The Bio21 Molecular Science and Biotechnology Institute; The University of Melbourne; Melbourne Victoria Australia
| | - Margaret Ayers
- Department of Pathology; The University of Melbourne; Melbourne Victoria Australia
| | - Yao Lulu Xing
- The Florey Institute of Neuroscience and Mental Health; The University of Melbourne; Melbourne Victoria Australia
| | - Ben Emery
- The Florey Institute of Neuroscience and Mental Health; The University of Melbourne; Melbourne Victoria Australia
- Department of Anatomy and Neuroscience; The University of Melbourne; Melbourne Victoria Australia
| | - Roberto Cappai
- Department of Pathology; The University of Melbourne; Melbourne Victoria Australia
- The Bio21 Molecular Science and Biotechnology Institute; The University of Melbourne; Melbourne Victoria Australia
- Department of Pharmacology and Therapeutics; The University of Melbourne; Melbourne Victoria Australia
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19
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Gilloteaux J, Subramanian K, Solomon N, Nicaise C. The leptin receptor mutation of the obese Zucker rat causes sciatic nerve demyelination with a centripetal pattern defect. Ultrastruct Pathol 2018; 42:377-408. [PMID: 30339059 DOI: 10.1080/01913123.2018.1522405] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Young male Zucker rats with a leptin receptor mutation are obese, have a non-insulin-dependent diabetes mellitus (NIDDM), and other endocrinopathies. Tibial branches of the sciatic nerve reveal a progressive demyelination that progresses out of the Schwann cells (SCs) where electron-contrast deposits are accumulated while the minor lines or intermembranous SC contacts display exaggerated spacings. Cajal bands contain diversely contrasted vesicles adjacent to the abaxonal myelin layer with blemishes; they appear dispatched centripetally out of many narrow electron densities, regularly spaced around the myelin annulus. These anomalies widen and yield into sectors across the stacked myelin layers. Throughout the worse degradations, the adaxonal membrane remains along the axonal neuroplasm. This peripheral neuropathy with irresponsive leptin cannot modulate hypothalamic-pituitary-adrenal axis and SC neurosteroids, thus exacerbates NIDDM condition. Additionally, the ultrastructure of the progressive myelin alterations may have unraveled a peculiar, centripetal mode of trafficking maintenance of the peripheral nervous system myelin, while some adhesive glycoproteins remain between myelin layers, somewhat hindering the axon mutilation. Heading title: Peripheral neuropathy and myelin.
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Affiliation(s)
- Jacques Gilloteaux
- a Department of Anatomical Sciences , St George's University School of Medicine, K.B. Taylor Global Scholar's Program at Northumbria University , Newcastle upon Tyne , UK.,b Unité de Recherche en Physiologie Moléculaire (URPhyM), Laboratoire de Neurodégénérescence et Régénération, Département de Médecine , Université de Namur , Namur , Belgium
| | - Kritika Subramanian
- a Department of Anatomical Sciences , St George's University School of Medicine, K.B. Taylor Global Scholar's Program at Northumbria University , Newcastle upon Tyne , UK.,c Department of Clinical and Epidemiological Virology , Rega Institute of Medical Research, Katholiele Universiteit Leuven , Leuven , Belgium
| | - Nadia Solomon
- a Department of Anatomical Sciences , St George's University School of Medicine, K.B. Taylor Global Scholar's Program at Northumbria University , Newcastle upon Tyne , UK
| | - Charles Nicaise
- b Unité de Recherche en Physiologie Moléculaire (URPhyM), Laboratoire de Neurodégénérescence et Régénération, Département de Médecine , Université de Namur , Namur , Belgium
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20
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Pathological transitions in myelin membranes driven by environmental and multiple sclerosis conditions. Proc Natl Acad Sci U S A 2018; 115:11156-11161. [PMID: 30322944 PMCID: PMC6217380 DOI: 10.1073/pnas.1804275115] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
In demyelination diseases, such as multiple sclerosis, the structure of the axons’ protective sheaths is disrupted. Due to the proximity of cytoplasmic myelin membrane to structural phase transition, minor alterations in the local environmental conditions can have devastating results. Using small-angle X-ray scattering and cryogenic transmission electron microscopy, we show that drastic structural reorganization and instabilities of myelin membrane are linked to specific environmental conditions and molecular composition in healthy and diseased states. These instabilities involve phase transition from the healthy lamellar membranes to pathological inverted hexagonal phase. These results highlight that local environmental conditions are critical for myelin function and should be considered as alternative routes for early pathology and as a means to avoid the initiation of demyelination. Multiple sclerosis (MS) is an autoimmune disease, leading to the destruction of the myelin sheaths, the protective layers surrounding the axons. The etiology of the disease is unknown, although there are several postulated environmental factors that may contribute to it. Recently, myelin damage was correlated to structural phase transition from a healthy stack of lamellas to a diseased inverted hexagonal phase as a result of the altered lipid stoichiometry and low myelin basic protein (MBP) content. In this work, we show that environmental conditions, such as buffer salinity and temperature, induce the same pathological phase transition as in the case of the lipid composition in the absence of MBP. These phase transitions have different transition points, which depend on the lipid’s compositions, and are ion specific. In extreme environmental conditions, we find an additional dense lamellar phase and that the native lipid composition results in similar pathology as the diseased composition. These findings demonstrate that several local environmental changes can trigger pathological structural changes. We postulate that these structural modifications result in myelin membrane vulnerability to the immune system attacks and thus can help explain MS etiology.
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21
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Ferrer I. Oligodendrogliopathy in neurodegenerative diseases with abnormal protein aggregates: The forgotten partner. Prog Neurobiol 2018; 169:24-54. [DOI: 10.1016/j.pneurobio.2018.07.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 07/24/2018] [Accepted: 07/27/2018] [Indexed: 12/31/2022]
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22
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Janowska J, Sypecka J. Therapeutic Strategies for Leukodystrophic Disorders Resulting from Perinatal Asphyxia: Focus on Myelinating Oligodendrocytes. Mol Neurobiol 2018; 55:4388-4402. [PMID: 28660484 PMCID: PMC5884907 DOI: 10.1007/s12035-017-0647-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 06/07/2017] [Indexed: 12/12/2022]
Abstract
Perinatal asphyxia results from the action of different risk factors like complications during pregnancy, preterm delivery, or long and difficult labor. Nowadays, it is still the leading cause of neonatal brain injury known as hypoxic-ischemic encephalopathy (HIE) and resulting neurological disorders. A temporal limitation of oxygen, glucose, and trophic factors supply results in alteration of neural cell differentiation and functioning and/or leads to their death. Among the affected cells are oligodendrocytes, responsible for myelinating the central nervous system (CNS) and formation of white matter. Therefore, one of the major consequences of the experienced HIE is leukodystrophic diseases resulting from oligodendrocyte deficiency or malfunctioning. The therapeutic strategies applied after perinatal asphyxia are aimed at reducing brain damage and promoting the endogenous neuroreparative mechanisms. In this review, we focus on the biology of oligodendrocytes and discuss present clinical treatments in the context of their efficiency in preserving white matter structure and preventing cognitive and behavioral deficits after perinatal asphyxia.
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Affiliation(s)
- Justyna Janowska
- NeuroRepair Department, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego str., 02-106, Warsaw, Poland
| | - Joanna Sypecka
- NeuroRepair Department, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego str., 02-106, Warsaw, Poland.
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23
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Janowska J, Ziemka-Nalecz M, Sypecka J. The Differentiation of Rat Oligodendroglial Cells Is Highly Influenced by the Oxygen Tension: In Vitro Model Mimicking Physiologically Normoxic Conditions. Int J Mol Sci 2018; 19:ijms19020331. [PMID: 29364139 PMCID: PMC5855553 DOI: 10.3390/ijms19020331] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 01/15/2018] [Accepted: 01/18/2018] [Indexed: 12/22/2022] Open
Abstract
Oligodendrocyte progenitor cells (OPCs) constitute one of the main populations of dividing cells in the central nervous system (CNS). Physiologically, OPCs give rise to mature, myelinating oligodendrocytes and confer trophic support to their neighboring cells within the nervous tissue. OPCs are known to be extremely sensitive to the influence of exogenous clues which might affect their crucial biological processes, like survival, proliferation, differentiation, and the ability to generate a myelin membrane. Alterations in their differentiation influencing their final potential for myelinogenesis are usually the leading cause of CNS dys- and demyelination, contributing to the development of leukodystrophic disorders. The evaluation of the mechanisms that cause oligodendrocytes to malfunction requires detailed studies based on designed in vitro models. Since OPCs readily respond to changes in local homeostasis, it is crucial to establish restricted culture conditions to eliminate the potential stimuli that might influence oligodendrocyte biology. Additionally, the in vitro settings should mimic the physiological conditions to enable the obtained results to be translated to future preclinical studies. Therefore, the aim of our study was to investigate OPC differentiation in physiological normoxia (5% O2) and a restricted in vitro microenvironment. To evaluate the impact of the combined microenvironmental clues derived from other components of the nervous tissue, which are also influenced by the local oxygen concentration, the process of generating OPCs was additionally analyzed in organotypic hippocampal slices. The obtained results show that OPC differentiation, although significantly slowed down, proceeded correctly through its typical stages in the physiologically relevant conditions created in vitro. The established settings were also conducive to efficient cell proliferation, exerting also a neuroprotective effect by promoting the proliferation of neurons. In conclusion, the performed studies show how oxygen tension influences OPC proliferation, differentiation, and their ability to express myelin components, and should be taken into consideration while planning preclinical studies, e.g., to examine neurotoxic compounds or to test neuroprotective strategies.
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Affiliation(s)
- Justyna Janowska
- NeuroRepair Department, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego Street, 02-106 Warsaw, Poland.
| | - Malgorzata Ziemka-Nalecz
- NeuroRepair Department, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego Street, 02-106 Warsaw, Poland.
| | - Joanna Sypecka
- NeuroRepair Department, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego Street, 02-106 Warsaw, Poland.
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Hoch-Kraft P, White R, Tenzer S, Krämer-Albers EM, Trotter J, Gonsior C. Dual role of the RNA helicase DDX5 in post-transcriptional regulation of Myelin Basic Protein in oligodendrocytes. J Cell Sci 2018; 131:jcs.204750. [DOI: 10.1242/jcs.204750] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 03/28/2018] [Indexed: 01/11/2023] Open
Abstract
In the central nervous system, oligodendroglial expression of Myelin Basic Protein (MBP) is crucial for the assembly and structure of the myelin sheath. MBP synthesis is tightly regulated in space and time, particularly on the post-transcriptional level. We have identified the DEAD-box RNA helicase DDX5 (alias p68) in a complex with Mbp mRNA in oligodendroglial cells. Expression of DDX5 is highest in progenitor cells and immature oligodendrocytes, where it localizes to heterogeneous populations of cytoplasmic ribonucleoprotein (RNP) complexes associated with Mbp mRNA in the cell body and processes. Manipulation of DDX5 protein amounts inversely affects levels of MBP protein. We present evidence that DDX5 is involved in post-transcriptional regulation of MBP protein synthesis, with implications for oligodendroglial development. In addition, DDX5 knockdown results in an increased abundance of MBP exon 2-positive isoforms in immature oligodendrocytes, most likely by regulating alternative splicing of Mbp. Our findings contribute to the understanding of the complex nature of MBP post-transcriptional control in immature oligodendrocytes where DDX5 appears to affect the abundance of MBP proteins via distinct but converging mechanisms.
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Affiliation(s)
- Peter Hoch-Kraft
- Molecular Cell Biology, Institute for Developmental Biology and Neurobiology, Johannes Gutenberg-University of Mainz, Anselm-Franz-von-Bentzelweg 3, 55128 Mainz, Germany
| | - Robin White
- Molecular Cell Biology, Institute for Developmental Biology and Neurobiology, Johannes Gutenberg-University of Mainz, Anselm-Franz-von-Bentzelweg 3, 55128 Mainz, Germany
- Institute of Physiology and Pathophysiology, University Medical Center of the Johannes Gutenberg-University, Duesbergweg 6, 55128 Mainz, Germany
| | - Stefan Tenzer
- Institute for Immunology, University Medical Center Mainz, Langenbeckstr. 1, 55131 Mainz, Germany
| | - Eva-Maria Krämer-Albers
- Molecular Cell Biology, Institute for Developmental Biology and Neurobiology, Johannes Gutenberg-University of Mainz, Anselm-Franz-von-Bentzelweg 3, 55128 Mainz, Germany
| | - Jacqueline Trotter
- Molecular Cell Biology, Institute for Developmental Biology and Neurobiology, Johannes Gutenberg-University of Mainz, Anselm-Franz-von-Bentzelweg 3, 55128 Mainz, Germany
| | - Constantin Gonsior
- Molecular Cell Biology, Institute for Developmental Biology and Neurobiology, Johannes Gutenberg-University of Mainz, Anselm-Franz-von-Bentzelweg 3, 55128 Mainz, Germany
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25
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García-Mateo N, Pascua-Maestro R, Pérez-Castellanos A, Lillo C, Sanchez D, Ganfornina MD. Myelin extracellular leaflet compaction requires apolipoprotein D membrane management to optimize lysosomal-dependent recycling and glycocalyx removal. Glia 2017; 66:670-687. [PMID: 29222871 DOI: 10.1002/glia.23274] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 11/09/2017] [Accepted: 11/17/2017] [Indexed: 11/07/2022]
Abstract
To compact the extracellular sides of myelin, an important transition must take place: from membrane sliding, while building the wraps, to membrane adhesion and water exclusion. Removal of the negatively charged glycocalyx becomes the limiting factor in such transition. What is required to initiate this membrane-zipping process? Knocking-out the Lipocalin Apolipoprotein D (ApoD), essential for lysosomal functional integrity in glial cells, results in a specific defect in myelin extracellular leaflet compaction in peripheral and central nervous system, which results in reduced conduction velocity and suboptimal behavioral outputs: motor learning is compromised. Myelination initiation, growth, intracellular leaflet compaction, myelin thickness or internodal length remain unaltered. Lack of ApoD specifically modifies Plp and P0 protein expression, but not Mbp or Mag. Late in myelin maturation period, ApoD affects lipogenic and growth-related, but not stress-responsive, signaling pathways. Without ApoD, the sialylated glycocalyx is maintained and ganglioside content remains high. In peripheral nervous system, Neu3 membrane sialidase and lysosomal Neu1 are coordinately expressed with ApoD in subsets of Schwann cells. ApoD-KO myelin becomes depleted of Neu3 and enriched in Fyn, a kinase with pivotal roles in transducing axon-derived signals into myelin properties. In the absence of ApoD, partial permeabilization of lysosomes alters Neu1 location as well. Exogenous ApoD rescues ApoD-KO hypersialylated glycocalyx in astrocytes, demonstrating that ApoD is necessary and sufficient to control glycocalyx composition in glial cells. By ensuring lysosomal functional integrity and adequate subcellular location of effector and regulatory proteins, ApoD guarantees the glycolipid recycling and glycocalyx removal required to complete myelin compaction.
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Affiliation(s)
- Nadia García-Mateo
- Instituto de Biología y Genética Molecular-Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid-CSIC, Valladolid, Spain
| | - Raquel Pascua-Maestro
- Instituto de Biología y Genética Molecular-Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid-CSIC, Valladolid, Spain
| | - Alberto Pérez-Castellanos
- Instituto de Biología y Genética Molecular-Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid-CSIC, Valladolid, Spain
| | - Concepción Lillo
- Instituto de Neurociencias de Castilla y León, IBSAL, Universidad de Salamanca, Salamanca, Spain
| | - Diego Sanchez
- Instituto de Biología y Genética Molecular-Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid-CSIC, Valladolid, Spain
| | - Maria D Ganfornina
- Instituto de Biología y Genética Molecular-Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid-CSIC, Valladolid, Spain
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26
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Sarbu N, Shih RY, Jones RV, Horkayne-Szakaly I, Oleaga L, Smirniotopoulos JG. White Matter Diseases with Radiologic-Pathologic Correlation. Radiographics 2017; 36:1426-47. [PMID: 27618323 DOI: 10.1148/rg.2016160031] [Citation(s) in RCA: 114] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
White matter diseases include a wide spectrum of disorders that have in common impairment of normal myelination, either by secondary destruction of previously myelinated structures (demyelinating processes) or by primary abnormalities of myelin formation (dysmyelinating processes). The pathogenesis of many white matter diseases remains poorly understood. Demyelinating disorders are the object of this review and will be further divided into autoimmune, infectious, vascular, and toxic-metabolic processes. Autoimmune processes include multiple sclerosis and related diseases: tumefactive demyelinating lesions, Balo concentric sclerosis, Marburg and Schilder variants, neuromyelitis optica (Devic disease), acute disseminated encephalomyelitis, and acute hemorrhagic leukoencephalopathy (Hurst disease). Infectious processes include Lyme disease (neuroborreliosis), progressive multifocal leukoencephalopathy, and human immunodeficiency virus (HIV) encephalopathy. Vascular processes include different types of small-vessel disease: arteriolosclerosis, cerebral amyloid angiopathy, cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), primary angiitis of the central nervous system, Susac syndrome, and neurolupus. Toxic-metabolic processes include osmotic myelinolysis, methotrexate leukoencephalopathy, and posterior reversible encephalopathy syndrome. The imaging spectrum can vary widely from small multifocal white matter lesions to confluent or extensive white matter involvement. Understanding the pathologic substrate is fundamental for understanding the radiologic manifestations, and a systematic approach to the radiologic findings, in correlation with clinical and laboratory data, is crucial for narrowing the differential diagnosis. (©)RSNA, 2016.
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Affiliation(s)
- Nicolae Sarbu
- From the Department of Radiology, Hospital Clínic Barcelona, Barcelona, Spain (N.S., L.O.); and American Institute for Radiologic Pathology, Silver Spring, Md (R.Y.S., R.V.J., I.H.S., J.G.S.)
| | - Robert Y Shih
- From the Department of Radiology, Hospital Clínic Barcelona, Barcelona, Spain (N.S., L.O.); and American Institute for Radiologic Pathology, Silver Spring, Md (R.Y.S., R.V.J., I.H.S., J.G.S.)
| | - Robert V Jones
- From the Department of Radiology, Hospital Clínic Barcelona, Barcelona, Spain (N.S., L.O.); and American Institute for Radiologic Pathology, Silver Spring, Md (R.Y.S., R.V.J., I.H.S., J.G.S.)
| | - Iren Horkayne-Szakaly
- From the Department of Radiology, Hospital Clínic Barcelona, Barcelona, Spain (N.S., L.O.); and American Institute for Radiologic Pathology, Silver Spring, Md (R.Y.S., R.V.J., I.H.S., J.G.S.)
| | - Laura Oleaga
- From the Department of Radiology, Hospital Clínic Barcelona, Barcelona, Spain (N.S., L.O.); and American Institute for Radiologic Pathology, Silver Spring, Md (R.Y.S., R.V.J., I.H.S., J.G.S.)
| | - James G Smirniotopoulos
- From the Department of Radiology, Hospital Clínic Barcelona, Barcelona, Spain (N.S., L.O.); and American Institute for Radiologic Pathology, Silver Spring, Md (R.Y.S., R.V.J., I.H.S., J.G.S.)
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27
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Mittendorf KF, Marinko JT, Hampton CM, Ke Z, Hadziselimovic A, Schlebach JP, Law CL, Li J, Wright ER, Sanders CR, Ohi MD. Peripheral myelin protein 22 alters membrane architecture. SCIENCE ADVANCES 2017; 3:e1700220. [PMID: 28695207 PMCID: PMC5498104 DOI: 10.1126/sciadv.1700220] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 05/19/2017] [Indexed: 05/10/2023]
Abstract
Peripheral myelin protein 22 (PMP22) is highly expressed in myelinating Schwann cells of the peripheral nervous system. PMP22 genetic alterations cause the most common forms of Charcot-Marie-Tooth disease (CMTD), which is characterized by severe dysmyelination in the peripheral nerves. However, the functions of PMP22 in Schwann cell membranes remain unclear. We demonstrate that reconstitution of purified PMP22 into lipid vesicles results in the formation of compressed and cylindrically wrapped protein-lipid vesicles that share common organizational traits with compact myelin of peripheral nerves in vivo. The formation of these myelin-like assemblies depends on the lipid-to-PMP22 ratio, as well as on the PMP22 extracellular loops. Formation of the myelin-like assemblies is disrupted by a CMTD-causing mutation. This study provides both a biochemical assay for PMP22 function and evidence that PMP22 directly contributes to membrane organization in compact myelin.
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Affiliation(s)
- Kathleen F. Mittendorf
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37240, USA
| | - Justin T. Marinko
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37240, USA
| | - Cheri M. Hampton
- Division of Infectious Disease, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Zunlong Ke
- Division of Infectious Disease, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA
- School of Biology, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Arina Hadziselimovic
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37240, USA
| | - Jonathan P. Schlebach
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37240, USA
| | - Cheryl L. Law
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37240, USA
| | - Jun Li
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Elizabeth R. Wright
- Division of Infectious Disease, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Charles R. Sanders
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37240, USA
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Corresponding author. (M.D.O.); (C.R.S.)
| | - Melanie D. Ohi
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37240, USA
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA
- Corresponding author. (M.D.O.); (C.R.S.)
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28
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Bessonov K, Vassall KA, Harauz G. Docking and molecular dynamics simulations of the Fyn-SH3 domain with free and phospholipid bilayer-associated 18.5-kDa myelin basic protein (MBP)-Insights into a noncanonical and fuzzy interaction. Proteins 2017; 85:1336-1350. [PMID: 28380689 DOI: 10.1002/prot.25295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 03/03/2017] [Accepted: 03/27/2017] [Indexed: 01/06/2023]
Abstract
The molecular details of the association between the human Fyn-SH3 domain, and the fragment of 18.5-kDa myelin basic protein (MBP) spanning residues S38-S107 (denoted as xα2-peptide, murine sequence numbering), were studied in silico via docking and molecular dynamics over 50-ns trajectories. The results show that interaction between the two proteins is energetically favorable and heavily dependent on the MBP proline-rich region (P93-P98) in both aqueous and membrane environments. In aqueous conditions, the xα2-peptide/Fyn-SH3 complex adopts a "sandwich""-like structure. In the membrane context, the xα2-peptide interacts with the Fyn-SH3 domain via the proline-rich region and the β-sheets of Fyn-SH3, with the latter wrapping around the proline-rich region in a form of a clip. Moreover, the simulations corroborate prior experimental evidence of the importance of upstream segments beyond the canonical SH3-ligand. This study thus provides a more-detailed glimpse into the context-dependent interaction dynamics and importance of the β-sheets in Fyn-SH3 and proline-rich region of MBP. Proteins 2017; 85:1336-1350. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Kyrylo Bessonov
- Systems and Modeling Unit, Montefiore Institute, Université de Liège, Quartier Polytech 1, Allée de la Découverte 10, Liège, 4000, Belgium
| | - Kenrick A Vassall
- Department of Molecular and Cellular Biology, Biophysics Interdepartmental Group, and Collaborative Program in Neuroscience, University of Guelph, 50 Stone Road East, Guelph, Ontario, N1G 2W1, Canada
| | - George Harauz
- Department of Molecular and Cellular Biology, Biophysics Interdepartmental Group, and Collaborative Program in Neuroscience, University of Guelph, 50 Stone Road East, Guelph, Ontario, N1G 2W1, Canada
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29
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Abstract
Alzheimer's disease (AD) is a chronic neurodegenerative disorder and the most common cause of dementia among the elderly population. The good correlation between the density and neocortical spread of neurofibrillary tangles (NFTs) and the severity of cognitive impairment offers an opportunity to use a noninvasive imaging technique such as positron emission tomography (PET) for early diagnosis and staging of the disease. PET imaging of NFTs holds promise not only as a diagnostic tool but also because it may enable the development of disease-modifying therapeutics for AD. In this review, we focus on the structural diversity of tau PET tracers, the challenges related to identifying high-affinity and highly selective NFT ligands, and recent progress in the clinical development of tau PET radioligands.
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Affiliation(s)
- Hartmuth C Kolb
- Janssen Research and Development, Neuroscience Biomarkers, San Diego, California 92121
| | - José Ignacio Andrés
- Janssen Research and Development, Discovery Sciences, Janssen-Cilag S.A., 45007 Toledo, Spain
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30
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Pathogenesis of white matter changes in cerebral small vessel diseases: beyond vessel-intrinsic mechanisms. Clin Sci (Lond) 2017; 131:635-651. [DOI: 10.1042/cs20160380] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2016] [Revised: 01/04/2017] [Accepted: 01/16/2017] [Indexed: 01/08/2023]
Abstract
Cerebral small vessel diseases (SVDs) are a leading cause of age and hypertension-related stroke and dementia. The salient features of SVDs visible on conventional brain magnetic resonance images include white matter hyperintensities (WMHs) on T2-weighted images, small infarcts, macrohemorrhages, dilated perivascular spaces, microbleeds and brain atrophy. Among these, WMHs are the most common and often the earliest brain tissue changes. Moreover, over the past two decades, large population- and patient-based studies have established the clinical importance of WMHs, notably with respect to cognitive and motor disturbances. Here, we seek to provide a new and critical look at the pathogenesis of SVD-associated white matter (WM) changes. We first review our current knowledge of WM biology in the healthy brain, and then consider the main clinical and pathological features of WM changes in SVDs. The most widely held view is that SVD-associated WM lesions are caused by chronic hypoperfusion, impaired cerebrovascular reactivity (CVR) or blood–brain barrier (BBB) leakage. Here, we assess the arguments for and against each of these mechanisms based on population, patient and experimental model studies, and further discuss other potential mechanisms. Specifically, building on two recent seminal studies that have uncovered an anatomical and functional relationship between oligodendrocyte progenitor cells and blood vessels, we elaborate on how small vessel changes might compromise myelin remodelling and cause WM degeneration. Finally, we propose new directions for future studies on this hot research topic.
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31
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Shaharabani R, Ram-On M, Avinery R, Aharoni R, Arnon R, Talmon Y, Beck R. Structural Transition in Myelin Membrane as Initiator of Multiple Sclerosis. J Am Chem Soc 2016; 138:12159-65. [DOI: 10.1021/jacs.6b04826] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Rona Shaharabani
- Raymond & Beverly Sackler School of Chemistry, Tel Aviv University, Tel Aviv 6997801, Israel
- Tel
Aviv University Center for Nanoscience and Nanotechnology, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Maor Ram-On
- Department
of Chemical Engineering and the Russell Berrie Nanotechnology Institute
(RBNI), Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Ram Avinery
- Tel
Aviv University Center for Nanoscience and Nanotechnology, Tel Aviv University, Tel Aviv 6997801, Israel
- Raymond & Beverly Sackler School of Physics & Astronomy, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Rina Aharoni
- Department
of Immunology, The Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Ruth Arnon
- Department
of Immunology, The Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Yeshayahu Talmon
- Department
of Chemical Engineering and the Russell Berrie Nanotechnology Institute
(RBNI), Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Roy Beck
- Tel
Aviv University Center for Nanoscience and Nanotechnology, Tel Aviv University, Tel Aviv 6997801, Israel
- Raymond & Beverly Sackler School of Physics & Astronomy, Tel Aviv University, Tel Aviv 6997801, Israel
- Sagol School
of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
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32
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Schäfer I, Müller C, Luhmann HJ, White R. MOBP levels are regulated by Fyn kinase and affect the morphological differentiation of oligodendrocytes. J Cell Sci 2016; 129:930-42. [PMID: 26801084 DOI: 10.1242/jcs.172148] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 01/20/2016] [Indexed: 01/24/2023] Open
Abstract
Oligodendrocytes are the myelinating glial cells of the central nervous system (CNS). Myelin is formed by extensive wrapping of oligodendroglial processes around axonal segments, which ultimately allows a rapid saltatory conduction of action potentials within the CNS and sustains neuronal health. The non-receptor tyrosine kinase Fyn is an important signaling molecule in oligodendrocytes. It controls the morphological differentiation of oligodendrocytes and is an integrator of axon-glial signaling cascades leading to localized synthesis of myelin basic protein (MBP), which is essential for myelin formation. The abundant myelin-associated oligodendrocytic basic protein (MOBP) resembles MBP in several aspects and has also been reported to be localized as mRNA and translated in the peripheral myelin compartment. The signals initiating local MOBP synthesis are so far unknown and the cellular function of MOBP remains elusive. Here, we show, by several approaches in cultured primary oligodendrocytes, that MOBP synthesis is stimulated by Fyn activity. Moreover, we reveal a new function for MOBP in oligodendroglial morphological differentiation.
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Affiliation(s)
- Isabelle Schäfer
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, Mainz 55128, Germany
| | - Christina Müller
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, Mainz 55128, Germany
| | - Heiko J Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, Mainz 55128, Germany
| | - Robin White
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, Mainz 55128, Germany
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33
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MyelStones: the executive roles of myelin basic protein in myelin assembly and destabilization in multiple sclerosis. Biochem J 2015; 472:17-32. [DOI: 10.1042/bj20150710] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The classic isoforms of myelin basic protein (MBP, 14–21.5 kDa) are essential to formation of the multilamellar myelin sheath of the mammalian central nervous system (CNS). The predominant 18.5-kDa isoform links together the cytosolic surfaces of oligodendrocytes, but additionally participates in cytoskeletal turnover and membrane extension, Fyn-mediated signalling pathways, sequestration of phosphoinositides and maintenance of calcium homoeostasis. All MBP isoforms are intrinsically disordered proteins (IDPs) that interact via molecular recognition fragments (MoRFs), which thereby undergo local disorder-to-order transitions. Their conformations and associations are modulated by environment and by a dynamic barcode of post-translational modifications, particularly phosphorylation by mitogen-activated and other protein kinases and deimination [a hallmark of demyelination in multiple sclerosis (MS)]. The MBPs are thus to myelin what basic histones are to chromatin. Originally thought to be merely structural proteins forming an inert spool, histones are now known to be dynamic entities involved in epigenetic regulation and diseases such as cancer. Analogously, the MBPs are not mere adhesives of compact myelin, but active participants in oligodendrocyte proliferation and in membrane process extension and stabilization during myelinogenesis. A central segment of these proteins is pivotal in membrane-anchoring and SH3 domain (Src homology 3) interaction. We discuss in the present review advances in our understanding of conformational conversions of this classic basic protein upon membrane association, including new thermodynamic analyses of transitions into different structural ensembles and how a shift in the pattern of its post-translational modifications is associated with the pathogenesis and potentially onset of demyelination in MS.
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34
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Michalski JP, Kothary R. Oligodendrocytes in a Nutshell. Front Cell Neurosci 2015; 9:340. [PMID: 26388730 PMCID: PMC4556025 DOI: 10.3389/fncel.2015.00340] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 08/17/2015] [Indexed: 01/06/2023] Open
Abstract
Oligodendrocytes are the myelinating cells of the central nervous system (CNS). While the phrase is oft repeated and holds true, the last few years have borne witness to radical change in our understanding of this unique cell type. Once considered static glue, oligodendrocytes are now seen as plastic and adaptive, capable of reacting to a changing CNS. This review is intended as a primer and guide, exploring how the past 5 years have fundamentally altered our appreciation of oligodendrocyte development and CNS myelination.
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Affiliation(s)
- John-Paul Michalski
- Ottawa Hospital Research Institute , Ottawa, ON , Canada ; Department of Cellular and Molecular Medicine, University of Ottawa , Ottawa, ON , Canada
| | - Rashmi Kothary
- Ottawa Hospital Research Institute , Ottawa, ON , Canada ; Department of Cellular and Molecular Medicine, University of Ottawa , Ottawa, ON , Canada ; Department of Medicine, University of Ottawa , Ottawa, ON , Canada ; Centre for Neuromuscular Disease, University of Ottawa , Ottawa, ON , Canada
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35
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Müller C, Schäfer I, Luhmann HJ, White R. Oligodendroglial Argonaute protein Ago2 associates with molecules of the Mbp mRNA localization machinery and is a downstream target of Fyn kinase. Front Cell Neurosci 2015; 9:328. [PMID: 26379499 PMCID: PMC4548153 DOI: 10.3389/fncel.2015.00328] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 08/10/2015] [Indexed: 01/10/2023] Open
Abstract
Oligodendrocytes myelinate neuronal axons in the central nervous system (CNS) facilitating rapid transmission of action potentials by saltatory conduction. Myelin basic protein (MBP) is an essential component of myelin and its absence results in severe hypomyelination in the CNS of rodents. Mbp mRNA is not translated immediately after exit from the nucleus in the cytoplasm, but is transported to the plasma membrane in RNA transport granules in a translationally silenced state. We have previously identified the small non-coding RNA 715 (sncRNA715) as an inhibitor of Mbp translation associated with RNA granules. Argonaute (Ago) proteins and small RNAs form the minimal core of the RNA induced silencing complex and together recognize target mRNAs to be translationally inhibited or degraded. Recently, tyrosine phosphorylation of Ago2 was reported to be a regulator of small RNA binding. The oligodendroglial non-receptor tyrosine kinase Fyn is activated by neuronal signals and stimulates the translation of Mbp mRNA at the axon-glial contact site. Here we analyzed the expression of Ago proteins in oligodendrocytes, if they associate with Mbp mRNA transport granules and are tyrosine phosphorylated by Fyn. We show that all Ago proteins (Ago1-4) are expressed by oligodendrocytes and that Ago2 colocalizes with hnRNP A2 in granular cytoplasmic structures. Ago2 associates with hnRNP A2, Mbp mRNA, sncRNA715 and Fyn kinase and is tyrosine phosphorylated in response to Fyn activity. Our findings suggest an involvement of Ago2 in the translational regulation of Mbp. The identification of Ago proteins as Fyn targets will foster further research to understand in more molecular detail how Fyn activity regulates Mbp translation.
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Affiliation(s)
| | | | | | - Robin White
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, MainzGermany
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Abstract
Myelinated nerve fibers have evolved to enable fast and efficient transduction of electrical signals in the nervous system. To act as an electric insulator, the myelin sheath is formed as a multilamellar membrane structure by the spiral wrapping and subsequent compaction of the oligodendroglial plasma membrane around central nervous system (CNS) axons. Current evidence indicates that the myelin sheath is more than an inert insulating membrane structure. Oligodendrocytes are metabolically active and functionally connected to the subjacent axon via cytoplasmic-rich myelinic channels for movement of macromolecules to and from the internodal periaxonal space under the myelin sheath. This review summarizes our current understanding of how myelin is generated and also the role of oligodendrocytes in supporting the long-term integrity of myelinated axons.
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Affiliation(s)
- Mikael Simons
- Cellular Neuroscience, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany Department of Neurology, University of Göttingen, 37075 Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
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Hovhannisyan A, Benkner B, Biesemeier A, Schraermeyer U, Kukley M, Münch TA. Effects of the jimpy mutation on mouse retinal structure and function. J Comp Neurol 2015; 523:2788-806. [PMID: 26011242 DOI: 10.1002/cne.23818] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 10/30/2014] [Accepted: 05/19/2015] [Indexed: 12/15/2022]
Abstract
The Jimpy mutant mouse has a point mutation in the proteolipid protein gene (plp1). The resulting misfolding of the protein leads to oligodendrocyte death, myelin destruction, and failure to produce adequately myelinated axons in the central nervous system (CNS). It is not known how the absence of normal myelination during development influences neural function. We characterized the Jimpy mouse retina to find out whether lack of myelination in the optic nerve during development has an effect on normal functioning and morphology of the retina. Optokinetic reflex measurements showed that Jimpy mice had, in general, a functional visual system. Both PLP1 antibody staining and reverse transcriptase-polymerase chain reaction for plp1 mRNA showed that plp1 is not expressed in the wild-type retina. However, in the optic nerve, plp1 is normally expressed, and consequently, in Jimpy mutant mice, myelination of axons in the optic nerve was mostly absent. Nevertheless, neither axon count nor axon ultrastructure in the optic nerve was affected. Physiological recordings of ganglion cell activity using microelectrode arrays revealed a decrease of stimulus-evoked activity at mesopic light levels. Morphological analysis of the retina did not show any significant differences in the gross morphology, such as thickness of retinal layers or cell number in the inner and outer nuclear layer. The cell bodies in the inner nuclear layer, however, were larger in the peripheral retina of Jimpy mutant mice. Antibody labeling against cell type-specific markers showed that the number of rod bipolar and horizontal cells was increased in Jimpy mice. In conclusion, whereas the Jimpy mutation has dramatic effects on the myelination of retinal ganglion cell axons, it has moderate effects on retinal morphology and function.
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Affiliation(s)
- Anahit Hovhannisyan
- Retinal Circuits and Optogenetics, Center for Integrative Neuroscience, University of Tübingen, 72076, Tübingen, Germany.,Neuron Glia Interactions, Center for Integrative Neuroscience, University of Tübingen, 72076, Tübingen, Germany
| | - Boris Benkner
- Retinal Circuits and Optogenetics, Center for Integrative Neuroscience, University of Tübingen, 72076, Tübingen, Germany
| | - Antje Biesemeier
- Section of Experimental Vitreoretinal Surgery, Center for Ophthalmology, 72076, Tübingen, Germany
| | - Ulrich Schraermeyer
- Section of Experimental Vitreoretinal Surgery, Center for Ophthalmology, 72076, Tübingen, Germany
| | - Maria Kukley
- Neuron Glia Interactions, Center for Integrative Neuroscience, University of Tübingen, 72076, Tübingen, Germany
| | - Thomas A Münch
- Retinal Circuits and Optogenetics, Center for Integrative Neuroscience, University of Tübingen, 72076, Tübingen, Germany
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Vassall KA, Jenkins AD, Bamm VV, Harauz G. Thermodynamic Analysis of the Disorder-to-α-Helical Transition of 18.5-kDa Myelin Basic Protein Reveals an Equilibrium Intermediate Representing the Most Compact Conformation. J Mol Biol 2015; 427:1977-92. [DOI: 10.1016/j.jmb.2015.03.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 03/11/2015] [Accepted: 03/17/2015] [Indexed: 10/23/2022]
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Zienowicz A, Bamm VV, Vassall KA, Harauz G. Myelin basic protein is a glial microtubule-associated protein – Characterization of binding domains, kinetics of polymerization, and regulation by phosphorylation and a lipidic environment. Biochem Biophys Res Commun 2015; 461:136-41. [DOI: 10.1016/j.bbrc.2015.03.181] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 03/31/2015] [Indexed: 12/12/2022]
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Abstract
The myelin sheath is a plasma membrane extension that is laid down in regularly spaced segments along axons of the nervous system. This process involves extensive changes in oligodendrocyte cell shape and membrane architecture. In this Cell Science at a Glance article and accompanying poster, we provide a model of how myelin of the central nervous system is wrapped around axons to form a tightly compacted, multilayered membrane structure. This model may not only explain how myelin is generated during brain development, but could also help us to understand myelin remodeling in adult life, which might serve as a form of plasticity for the fine-tuning of neuronal networks.
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Affiliation(s)
- Nicolas Snaidero
- Max Planck Institute of Experimental Medicine, Cellular Neuroscience, Hermann-Rein-Strasse. 3, 37075, Göttingen, Germany Department of Neurology, University of Göttingen, Robert-Koch-Strasse. 40, 37075, Göttingen, Germany
| | - Mikael Simons
- Max Planck Institute of Experimental Medicine, Cellular Neuroscience, Hermann-Rein-Strasse. 3, 37075, Göttingen, Germany Department of Neurology, University of Göttingen, Robert-Koch-Strasse. 40, 37075, Göttingen, Germany
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Ariza M, Kolb HC, Moechars D, Rombouts F, Andrés JI. Tau Positron Emission Tomography (PET) Imaging: Past, Present, and Future. J Med Chem 2015; 58:4365-82. [DOI: 10.1021/jm5017544] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Manuela Ariza
- Neuroscience Medicinal Chemistry, Janssen Research and Development, a Division of Janssen Pharmaceutica NV, Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - Hartmuth C. Kolb
- Neuroscience Biomarkers, Janssen Research and Development, 3210 Merryfield Row, San Diego, California 92121, United States
| | - Dieder Moechars
- Neuroscience Discovery Biology, Janssen Research and Development, a Division of Janssen Pharmaceutica NV, Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - Frederik Rombouts
- Neuroscience Medicinal Chemistry, Janssen Research and Development, a Division of Janssen Pharmaceutica NV, Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - José Ignacio Andrés
- Discovery Sciences, Janssen Research and Development, a Division of Janssen-Cilag, Jarama 75, 45007 Toledo, Spain
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Jang SY, Shin YK, Park SY, Park JY, Rha SH, Kim JK, Lee HJ, Park HT. Autophagy is involved in the reduction of myelinating Schwann cell cytoplasm during myelin maturation of the peripheral nerve. PLoS One 2015; 10:e0116624. [PMID: 25581066 PMCID: PMC4291222 DOI: 10.1371/journal.pone.0116624] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 12/11/2014] [Indexed: 12/21/2022] Open
Abstract
Peripheral nerve myelination involves dynamic changes in Schwann cell morphology and membrane structure. Recent studies have demonstrated that autophagy regulates organelle biogenesis and plasma membrane dynamics. In the present study, we investigated the role of autophagy in the development and differentiation of myelinating Schwann cells during sciatic nerve myelination. Electron microscopy and biochemical assays have shown that Schwann cells remove excess cytoplasmic organelles during myelination through macroautophagy. Inhibition of autophagy via Schwann cell-specific removal of ATG7, an essential molecule for macroautophagy, using a conditional knockout strategy, resulted in abnormally enlarged abaxonal cytoplasm in myelinating Schwann cells that contained a large number of ribosomes and an atypically expanded endoplasmic reticulum. Small fiber hypermyelination and minor anomalous peripheral nerve functions are observed in this mutant. Rapamycin-induced suppression of mTOR activity during the early postnatal period enhanced not only autophagy but also developmental reduction of myelinating Schwann cells cytoplasm in vivo. Together, our findings suggest that autophagy is a regulatory mechanism of Schwann cells structural plasticity during myelination.
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Affiliation(s)
- So Young Jang
- Department of Physiology, Mitochondria Hub Regulation Center, Busan, Korea
| | - Yoon Kyung Shin
- Department of Physiology, Mitochondria Hub Regulation Center, Busan, Korea
| | - So Young Park
- Department of Pharmacology, Mitochondria Hub Regulation Center, Busan, Korea
| | - Joo Youn Park
- Department of Physiology, Mitochondria Hub Regulation Center, Busan, Korea
| | - Seo-Hee Rha
- Department of Pathology, College of Medicine, Dong-A University, Busan, Korea
| | - Jong Kuk Kim
- Department of Neurology, College of Medicine, Dong-A University, Busan, Korea
| | - Hye Jeong Lee
- Department of Pharmacology, Mitochondria Hub Regulation Center, Busan, Korea
| | - Hwan Tae Park
- Department of Physiology, Mitochondria Hub Regulation Center, Busan, Korea
- * E-mail:
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Schmitt S, Castelvetri LC, Simons M. Metabolism and functions of lipids in myelin. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1851:999-1005. [PMID: 25542507 DOI: 10.1016/j.bbalip.2014.12.016] [Citation(s) in RCA: 164] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 12/08/2014] [Accepted: 12/16/2014] [Indexed: 12/16/2022]
Abstract
Rapid conduction of nerve impulses requires coating of axons by myelin sheaths, which are lipid-rich and multilamellar membrane stacks. The lipid composition of myelin varies significantly from other biological membranes. Studies in mutant mice targeting various lipid biosynthesis pathways have shown that myelinating glia have a remarkable capacity to compensate the lack of individual lipids. However, compensation fails when it comes to maintaining long-term stability of myelin. Here, we summarize how lipids function in myelin biogenesis, axon-glia communication and in supporting long-term maintenance of myelin. We postulate that change in myelin lipid composition might be relevant for our understanding of aging and demyelinating diseases. This article is part of a Special Issue titled Brain Lipids.
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Affiliation(s)
- Sebastian Schmitt
- Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Str. 3, Göttingen, Germany; Department of Neurology, Robert-Koch-Str. 40, University of Göttingen, Göttingen, Germany
| | - Ludovici Cantuti Castelvetri
- Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Str. 3, Göttingen, Germany; Department of Neurology, Robert-Koch-Str. 40, University of Göttingen, Göttingen, Germany
| | - Mikael Simons
- Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Str. 3, Göttingen, Germany; Department of Neurology, Robert-Koch-Str. 40, University of Göttingen, Göttingen, Germany.
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The proline-rich region of 18.5 kDa myelin basic protein binds to the SH3-domain of Fyn tyrosine kinase with the aid of an upstream segment to form a dynamic complex in vitro. Biosci Rep 2014; 34:e00157. [PMID: 25343306 PMCID: PMC4266924 DOI: 10.1042/bsr20140149] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The intrinsically disordered 18.5 kDa classic isoform of MBP (myelin basic protein) interacts with Fyn kinase during oligodendrocyte development and myelination. It does so primarily via a central proline-rich SH3 (Src homology 3) ligand (T92–R104, murine 18.5 kDa MBP sequence numbering) that is part of a molecular switch due to its high degree of conservation and modification by MAP (mitogen-activated protein) and other kinases, especially at residues T92 and T95. Here, we show using co-transfection experiments of an early developmental oligodendroglial cell line (N19) that an MBP segment upstream of the primary ligand is involved in MBP–Fyn–SH3 association in cellula. Using solution NMR spectroscopy in vitro, we define this segment to comprise MBP residues (T62–L68), and demonstrate further that residues (V83–P93) are the predominant SH3-target, assessed by the degree of chemical shift change upon titration. We show by chemical shift index analysis that there is no formation of local poly-proline type II structure in the proline-rich segment upon binding, and by NOE (nuclear Overhauser effect) and relaxation measurements that MBP remains dynamic even while complexed with Fyn–SH3. The association is a new example first of a non-canonical SH3-domain interaction and second of a fuzzy MBP complex. MBP interacts with Fyn kinase during oligodendrocyte development and myelination. We show that there is no binding-induced PPII formation in the primary ligand segment, and that a region upstream is required for in vitro interaction.
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Boggs JM, Homchaudhuri L, Ranagaraj G, Liu Y, Smith GST, Harauz G. Interaction of myelin basic protein with cytoskeletal and signaling proteins in cultured primary oligodendrocytes and N19 oligodendroglial cells. BMC Res Notes 2014; 7:387. [PMID: 24956930 PMCID: PMC4078013 DOI: 10.1186/1756-0500-7-387] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 06/18/2014] [Indexed: 12/13/2022] Open
Abstract
Background The classic myelin basic protein (MBP) isoforms are intrinsically-disordered proteins of 14–21.5 kDa in size arising from the Golli (Gene in the Oligodendrocyte Lineage) gene complex, and are responsible for formation of the multilayered myelin sheath in the central nervous system. The predominant membrane-associated isoform of MBP is not simply a structural component of compact myelin but is highly post-translationally modified and multi-functional, having interactions with numerous proteins such as Ca2+-calmodulin, and with actin, tubulin, and proteins with SH3-domains, which it can tether to a lipid membrane in vitro. It co-localizes with such proteins in primary oligodendrocytes (OLGs) and in early developmental N19-OLGs transfected with fluorescently-tagged MBP. Results To provide further evidence for MBP associations with these proteins in vivo, we show here that MBP isoforms are co-immunoprecipitated from detergent extracts of primary OLGs together with actin, tubulin, zonula occludens 1 (ZO-1), cortactin, and Fyn kinase. We also carry out live-cell imaging of N19-OLGs co-transfected with fluorescent MBP and actin, and show that when actin filaments re-assemble after recovery from cytochalasin D treatment, MBP and actin are rapidly enriched and co-localized at certain sites at the plasma membrane and in newly-formed membrane ruffles. The MBP and actin distributions change similarly with time, suggesting a specific and dynamic association. Conclusions These results provide more direct evidence for association of the predominant 18.5-kDa MBP isoform with these proteins in primary OLGs and in live cells than previously could be inferred from co-localization observations. This study supports further a role for classic MBP isoforms in protein-protein interactions during membrane and cytoskeletal extension and remodeling in OLGs.
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Affiliation(s)
- Joan M Boggs
- Molecular Structure and Function Program, Research Institute, Hospital for Sick Children, 686 Bay St, Toronto, ON M5G 0A4, Canada.
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