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Govender D, Moloko L, Papathanasopoulos M, Tumba N, Owen G, Calvey T. Ibogaine administration following repeated morphine administration upregulates myelination markers 2', 3'-cyclic nucleotide 3'-phosphodiesterase (CNP) and myelin basic protein (MBP) mRNA and protein expression in the internal capsule of Sprague Dawley rats. Front Neurosci 2024; 18:1378841. [PMID: 39114487 PMCID: PMC11303312 DOI: 10.3389/fnins.2024.1378841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 07/10/2024] [Indexed: 08/10/2024] Open
Abstract
Ibogaine is a psychedelic alkaloid being investigated as a possible treatment for opioid use disorder. Ibogaine has a multi-receptor profile with affinities for mu and kappa opioid as well as NMDA receptors amongst others. Due to the sparsity of research into ibogaine's effects on white matter integrity and given the growing evidence that opioid use disorder is characterized by white matter pathology, we set out to investigate ibogaine's effects on two markers of myelination, 2', 3'-cyclic nucleotide 3'-phosphodiesterase (CNP) and myelin basic protein (MBP). Fifty Sprague Dawley rats were randomly assigned to five experimental groups of n = 10; (1) a saline control group received daily saline injections for 10 days, (2) a morphine control group received escalating morphine doses from 5 to 15 mg/kg over 10 days, (3) an ibogaine control group that received 10 days of saline followed by 50 mg/kg ibogaine hydrochloride, (4) a combination morphine and ibogaine group 1 that received the escalating morphine regime followed by 50 mg/kg ibogaine hydrochloride and (5) a second combination morphine and ibogaine group 2 which followed the same morphine and ibogaine regimen yet was terminated 72 h after administration compared to 24 h in the other groups. White matter from the internal capsule was dissected and qPCR and western blotting determined protein and gene expression of CNP and MBP. Morphine upregulated CNPase whereas ibogaine alone had no effect on CNP mRNA or protein expression. However, ibogaine administration following repeated morphine administration had an immediate effect by increasing CNP mRNA expression. This effect diminished after 72 h and resulted in a highly significant upregulation of CNPase protein at 72 h post administration. Ibogaine administration alone significantly upregulated protein expression yet downregulated MBP mRNA expression. Ibogaine administration following repeated morphine administration significantly upregulated MBP mRNA expression which increased at 72 h post administration resulting in a highly significant upregulation of MBP protein expression at 72 h post administration. These findings indicate that ibogaine is able to upregulate genes and proteins involved in the process of remyelination following opioid use and highlights an important mechanism of action of ibogaine's ability to treat substance use disorders.
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Affiliation(s)
- Demi Govender
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Leila Moloko
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Maria Papathanasopoulos
- HIV Pathogenesis Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Nancy Tumba
- HIV Pathogenesis Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Gavin Owen
- HIV Pathogenesis Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Tanya Calvey
- Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Neuroscience Institute, University of Cape Town, Cape Town, South Africa
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Boseley RE, Sylvain NJ, Peeling L, Kelly ME, Pushie MJ. A review of concepts and methods for FTIR imaging of biomarker changes in the post-stroke brain. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184287. [PMID: 38266967 DOI: 10.1016/j.bbamem.2024.184287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 01/11/2024] [Accepted: 01/12/2024] [Indexed: 01/26/2024]
Abstract
Stroke represents a core area of study in neurosciences and public health due to its global contribution toward mortality and disability. The intricate pathophysiology of stroke, including ischemic and hemorrhagic events, involves the interruption in oxygen and nutrient delivery to the brain. Disruption of these crucial processes in the central nervous system leads to metabolic dysregulation and cell death. Fourier transform infrared (FTIR) spectroscopy can simultaneously measure total protein and lipid content along with a number of key biomarkers within brain tissue that cannot be observed using conventional techniques. FTIR imaging provides the opportunity to visualize this information in tissue which has not been chemically treated prior to analysis, thus retaining the spatial distribution and in situ chemical information. Here we present a review of FTIR imaging methods for investigating the biomarker responses in the post-stroke brain.
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Affiliation(s)
- Rhiannon E Boseley
- Department of Surgery, University of Saskatchewan, Saskatoon, SK S7N 0W8, Canada
| | - Nicole J Sylvain
- Department of Surgery, University of Saskatchewan, Saskatoon, SK S7N 0W8, Canada
| | - Lissa Peeling
- Department of Surgery, University of Saskatchewan, Saskatoon, SK S7N 0W8, Canada
| | - Michael E Kelly
- Department of Surgery, University of Saskatchewan, Saskatoon, SK S7N 0W8, Canada
| | - M Jake Pushie
- Department of Surgery, University of Saskatchewan, Saskatoon, SK S7N 0W8, Canada.
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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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4
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Dustin E, Suarez-Pozos E, Stotesberry C, Qiu S, Palavicini JP, Han X, Dupree JL. Compromised Myelin and Axonal Molecular Organization Following Adult-Onset Sulfatide Depletion. Biomedicines 2023; 11:1431. [PMID: 37239102 PMCID: PMC10216104 DOI: 10.3390/biomedicines11051431] [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: 03/31/2023] [Revised: 04/30/2023] [Accepted: 05/05/2023] [Indexed: 05/28/2023] Open
Abstract
3-O-sulfogalactosylceramide, or sulfatide, is a prominent myelin glycosphingolipid reduced in the normal appearing white matter (NAWM) in Multiple Sclerosis (MS), indicating that sulfatide reduction precedes demyelination. Using a mouse model that is constitutively depleted of sulfatide, we previously demonstrated that sulfatide is essential during development for the establishment and maintenance of myelin and axonal integrity and for the stable tethering of certain myelin proteins in the sheath. Here, using an adult-onset depletion model of sulfatide, we employ a combination of ultrastructural, immunohistochemical and biochemical approaches to analyze the consequence of sulfatide depletion from the adult CNS. Our findings show a progressive loss of axonal protein domain organization, which is accompanied by axonal degeneration, with myelin sparing. Similar to our previous work, we also observe differential myelin protein anchoring stabilities that are both sulfatide dependent and independent. Most notably, stable anchoring of neurofascin155, a myelin paranodal protein that binds the axonal paranodal complex of contactin/Caspr1, requires sulfatide. Together, our findings show that adult-onset sulfatide depletion, independent of demyelination, is sufficient to trigger progressive axonal degeneration. Although the pathologic mechanism is unknown, we propose that sulfatide is required for maintaining myelin organization and subsequent myelin-axon interactions and disruptions in these interactions results in compromised axon structure and function.
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Affiliation(s)
- Elizabeth Dustin
- Research Service, Richmond Veterans Affairs Medical Center, Central Virginia Veterans Affairs Health Care System, Richmond, VA 23249, USA; (E.D.)
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond VA 23298, USA
| | - Edna Suarez-Pozos
- Research Service, Richmond Veterans Affairs Medical Center, Central Virginia Veterans Affairs Health Care System, Richmond, VA 23249, USA; (E.D.)
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond VA 23298, USA
| | - Camryn Stotesberry
- Department of Biology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Shulan Qiu
- Sam and Ann Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
- Division of Diabetes, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Juan Pablo Palavicini
- Sam and Ann Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
- Division of Diabetes, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Xianlin Han
- Sam and Ann Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
- Division of Diabetes, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Jeffrey L. Dupree
- Research Service, Richmond Veterans Affairs Medical Center, Central Virginia Veterans Affairs Health Care System, Richmond, VA 23249, USA; (E.D.)
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond VA 23298, USA
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Tanaka T, Ohno N, Osanai Y, Saitoh S, Thai TQ, Nishimura K, Shinjo T, Takemura S, Tatsumi K, Wanaka A. Large-scale electron microscopic volume imaging of interfascicular oligodendrocytes in the mouse corpus callosum. Glia 2021; 69:2488-2502. [PMID: 34165804 DOI: 10.1002/glia.24055] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 06/11/2021] [Accepted: 06/16/2021] [Indexed: 12/16/2022]
Abstract
Single oligodendrocytes produce myelin sheaths around multiple axons in the central nervous system. Interfascicular oligodendrocytes (IOs) facilitate nerve conduction, but their detailed morphologies remain largely unknown. In the present study, we three-dimensionally reconstructed IOs in the corpus callosum of adult mouse using serial block face scanning electron microscopy. The cell bodies of IOs were morphologically polarized and extended thick processes from the cytoplasm-rich part of the cell. Processes originating from the cell body of each IO can be classified into two types: one myelinates an axon without branching, while the other type branches and each branch myelinates a distinct axon. Myelin sheaths originating from a particular IO have biased thicknesses, wrapping axons of a limited range of diameters. Consistent with this finding, IOs transduced and visualized with a rabies viral vector expressing GFP showed statistically significant variation in their myelination patterns. We further reconstructed the sheath immediately adjacent to that derived from each of the analyzed IOs; the thicknesses of the pair of sheaths were significantly correlated despite emanating from different IOs. These results suggest that a single axon could regulate myelin sheath thicknesses, even if the sheaths are derived from distinct IOs. Collectively, our results indicate that the IOs have their own myelin profiles defined by myelin thickness and axonal diameter although axons may regulate thickness of myelin sheath.
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Affiliation(s)
- Tatsuhide Tanaka
- Department of Anatomy and Neuroscience, Nara Medical University, Kashihara, Japan
| | - Nobuhiko Ohno
- Department of Anatomy, Division of Histology and Cell Biology, Jichi Medical University, School of Medicine, Shimotsuke, Japan
| | - Yasuyuki Osanai
- Department of Anatomy, Division of Histology and Cell Biology, Jichi Medical University, School of Medicine, Shimotsuke, Japan.,Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Japan
| | - Sei Saitoh
- Section of Electron Microscopy, Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Japan.,Department of Anatomy II and Cell Biology, Fujita Health University School of Medicine, Toyoake, Japan
| | - Truc Quynh Thai
- Department of Anatomy, Division of Histology and Cell Biology, Jichi Medical University, School of Medicine, Shimotsuke, Japan
| | - Kazuya Nishimura
- Department of Anatomy and Neuroscience, Nara Medical University, Kashihara, Japan
| | - Takeaki Shinjo
- Department of Anatomy and Neuroscience, Nara Medical University, Kashihara, Japan
| | - Shoko Takemura
- Department of Anatomy and Neuroscience, Nara Medical University, Kashihara, Japan
| | - Kouko Tatsumi
- Department of Anatomy and Neuroscience, Nara Medical University, Kashihara, Japan
| | - Akio Wanaka
- Department of Anatomy and Neuroscience, Nara Medical University, Kashihara, Japan
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de la Fuente L, Arzalluz-Luque Á, Tardáguila M, Del Risco H, Martí C, Tarazona S, Salguero P, Scott R, Lerma A, Alastrue-Agudo A, Bonilla P, Newman JRB, Kosugi S, McIntyre LM, Moreno-Manzano V, Conesa A. tappAS: a comprehensive computational framework for the analysis of the functional impact of differential splicing. Genome Biol 2020; 21:119. [PMID: 32423416 PMCID: PMC7236505 DOI: 10.1186/s13059-020-02028-w] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 04/23/2020] [Indexed: 12/26/2022] Open
Abstract
Recent advances in long-read sequencing solve inaccuracies in alternative transcript identification of full-length transcripts in short-read RNA-Seq data, which encourages the development of methods for isoform-centered functional analysis. Here, we present tappAS, the first framework to enable a comprehensive Functional Iso-Transcriptomics (FIT) analysis, which is effective at revealing the functional impact of context-specific post-transcriptional regulation. tappAS uses isoform-resolved annotation of coding and non-coding functional domains, motifs, and sites, in combination with novel analysis methods to interrogate different aspects of the functional readout of transcript variants and isoform regulation. tappAS software and documentation are available at https://app.tappas.org.
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Affiliation(s)
- Lorena de la Fuente
- Genomics of Gene Expression Laboratory, Prince Felipe Research Center, Valencia, Spain
- Present Address: Bioinformatics Unit, IIS Fundación Jiménez Díaz, Madrid, Spain
| | - Ángeles Arzalluz-Luque
- Department of Statistics and Operational Research, Polytechnical University of Valencia, Valencia, Spain
| | - Manuel Tardáguila
- Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences, University of Florida, Gainesville, FL, USA
- Present Address: Human Genetics Department, Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK
| | - Héctor Del Risco
- Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences, University of Florida, Gainesville, FL, USA
| | - Cristina Martí
- Genomics of Gene Expression Laboratory, Prince Felipe Research Center, Valencia, Spain
| | - Sonia Tarazona
- Department of Statistics and Operational Research, Polytechnical University of Valencia, Valencia, Spain
| | - Pedro Salguero
- Genomics of Gene Expression Laboratory, Prince Felipe Research Center, Valencia, Spain
| | - Raymond Scott
- Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences, University of Florida, Gainesville, FL, USA
| | - Alberto Lerma
- Genomics of Gene Expression Laboratory, Prince Felipe Research Center, Valencia, Spain
| | - Ana Alastrue-Agudo
- Present Address: Human Genetics Department, Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK
| | - Pablo Bonilla
- Present Address: Human Genetics Department, Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK
| | - Jeremy R B Newman
- Genetics Institute, University of Florida, Gainesville, FL, USA
- Department of Pathology, University of Florida, Gainesville, FL, USA
| | - Shunichi Kosugi
- Genetics Institute, University of Florida, Gainesville, FL, USA
- Laboratory for Statistical and Translational Genetics, Center for Integrative Medical Sciences, RIKEN, Wako, Japan
| | - Lauren M McIntyre
- Genetics Institute, University of Florida, Gainesville, FL, USA
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, USA
| | | | - Ana Conesa
- Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences, University of Florida, Gainesville, FL, USA.
- Genetics Institute, University of Florida, Gainesville, FL, USA.
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de Jong CGHM, Gabius HJ, Baron W. The emerging role of galectins in (re)myelination and its potential for developing new approaches to treat multiple sclerosis. Cell Mol Life Sci 2020; 77:1289-1317. [PMID: 31628495 PMCID: PMC7113233 DOI: 10.1007/s00018-019-03327-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 09/27/2019] [Accepted: 09/30/2019] [Indexed: 12/12/2022]
Abstract
Multiple sclerosis (MS) is an inflammatory, demyelinating and neurodegenerative disease of the central nervous system with unknown etiology. Currently approved disease-modifying treatment modalities are immunomodulatory or immunosuppressive. While the applied drugs reduce the frequency and severity of the attacks, their efficacy to regenerate myelin membranes and to halt disease progression is limited. To achieve such therapeutic aims, understanding biological mechanisms of remyelination and identifying factors that interfere with remyelination in MS can give respective directions. Such a perspective is given by the emerging functional profile of galectins. They form a family of tissue lectins, which are potent effectors in processes as diverse as adhesion, apoptosis, immune mediator release or migration. This review focuses on endogenous and exogenous roles of galectins in glial cells such as oligodendrocytes, astrocytes and microglia in the context of de- and (re)myelination and its dysregulation in MS. Evidence is arising for a cooperation among family members so that timed expression and/or secretion of galectins-1, -3 and -4 result in modifying developmental myelination, (neuro)inflammatory processes, de- and remyelination. Dissecting the mechanisms that underlie the distinct activities of galectins and identifying galectins as target or tool to modulate remyelination have the potential to contribute to the development of novel therapeutic strategies for MS.
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Affiliation(s)
- Charlotte G H M de Jong
- Department of Biomedical Sciences of Cells & Systems, Section Molecular Neurobiology, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Hans-Joachim Gabius
- Institute of Physiological Chemistry, Faculty of Veterinary Medicine, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Wia Baron
- Department of Biomedical Sciences of Cells & Systems, Section Molecular Neurobiology, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands.
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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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The Role of Vesicle Trafficking and Release in Oligodendrocyte Biology. Neurochem Res 2019; 45:620-629. [PMID: 31782103 DOI: 10.1007/s11064-019-02913-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 11/11/2019] [Accepted: 11/16/2019] [Indexed: 12/11/2022]
Abstract
Oligodendrocytes are a subtype of glial cells found within the central nervous system (CNS), responsible for the formation and maintenance of specialized myelin membranes which wrap neuronal axons. The development of myelin requires tight coordination for the cell to deliver lipid and protein building blocks to specific myelin segments at the right time. Both internal and external cues control myelination, thus the reception of these signals also requires precise regulation. In late years, a growing body of evidence indicates that oligodendrocytes, like many other cell types, may use extracellular vesicles (EVs) as a medium for transferring information. The field of EV research has expanded rapidly over the past decade, with new contributions that suggest EVs might have direct involvement in communications with neurons and other glial cells to fine tune oligodendroglial function. This functional role of EVs might also be maladaptive, as it has likewise been implicated in the spreading of toxic molecules within the brain during disease. In this review we will discuss the field's current understanding of extracellular vesicle biology within oligodendrocytes, and their contribution to physiologic and pathologic conditions.
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Baba H, Ishibashi T. The Role of Sulfatides in Axon–Glia Interactions. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1190:165-179. [DOI: 10.1007/978-981-32-9636-7_11] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Varela-Echevarría A, Vargas-Barroso V, Lozano-Flores C, Larriva-Sahd J. Is There Evidence for Myelin Modeling by Astrocytes in the Normal Adult Brain? Front Neuroanat 2017; 11:75. [PMID: 28932188 PMCID: PMC5592641 DOI: 10.3389/fnana.2017.00075] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 08/15/2017] [Indexed: 11/13/2022] Open
Abstract
A set of astrocytic process associated with altered myelinated axons is described in the forebrain of normal adult rodents with confocal, electron microscopy, and 3D reconstructions. Each process consists of a protuberance that contains secretory organelles including numerous lysosomes which polarize and open next to disrupted myelinated axons. Because of the distinctive asymmetric organelle distribution and ubiquity throughout the forebrain neuropil, this enlargement is named paraxial process (PAP). The myelin envelope contiguous to the PAP displays focal disruption or disintegration. In routine electron microscopy clusters of large, confluent, lysosomes proved to be an effective landmark for PAP identification. In 3D assemblies lysosomes organize a series of interconnected saccules that open up to the plasmalemma next to the disrupted myelin envelope(s). Activity for acid hydrolases was visualized in lysosomes, and extracellularly at the PAP-myelin interface and/or between the glial and neuronal outer aspects. Organelles in astrocytic processes involved in digesting pyknotic cells and debris resemble those encountered in PAPs supporting a likewise lytic function of the later. Conversely, processes entangling tripartite synapses and glomeruli were devoid of lysosomes. Both oligodendrocytic and microglial processes were not associated with altered myelin envelopes. The possible roles of the PAP in myelin remodeling in the context of the oligodendrocyte-astrocyte interactions and in the astrocyte's secretory pathways are discussed.
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Affiliation(s)
- Alfredo Varela-Echevarría
- Department of Developmental Biology and Neurophysiology, Instituto de Neurobiología Universidad Nacional Autónoma de MéxicoQuerétaro, Mexico
| | - Víctor Vargas-Barroso
- Department of Developmental Biology and Neurophysiology, Instituto de Neurobiología Universidad Nacional Autónoma de MéxicoQuerétaro, Mexico
| | - Carlos Lozano-Flores
- Department of Developmental Biology and Neurophysiology, Instituto de Neurobiología Universidad Nacional Autónoma de MéxicoQuerétaro, Mexico
| | - Jorge Larriva-Sahd
- Department of Developmental Biology and Neurophysiology, Instituto de Neurobiología Universidad Nacional Autónoma de MéxicoQuerétaro, Mexico
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Mironova YA, Lenk GM, Lin JP, Lee SJ, Twiss JL, Vaccari I, Bolino A, Havton LA, Min SH, Abrams CS, Shrager P, Meisler MH, Giger RJ. PI(3,5)P2 biosynthesis regulates oligodendrocyte differentiation by intrinsic and extrinsic mechanisms. eLife 2016; 5. [PMID: 27008179 PMCID: PMC4889328 DOI: 10.7554/elife.13023] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 03/23/2016] [Indexed: 12/18/2022] Open
Abstract
Proper development of the CNS axon-glia unit requires bi-directional communication between axons and oligodendrocytes (OLs). We show that the signaling lipid phosphatidylinositol-3,5-bisphosphate [PI(3,5)P2] is required in neurons and in OLs for normal CNS myelination. In mice, mutations of Fig4, Pikfyve or Vac14, encoding key components of the PI(3,5)P2 biosynthetic complex, each lead to impaired OL maturation, severe CNS hypomyelination and delayed propagation of compound action potentials. Primary OLs deficient in Fig4 accumulate large LAMP1+ and Rab7+ vesicular structures and exhibit reduced membrane sheet expansion. PI(3,5)P2 deficiency leads to accumulation of myelin-associated glycoprotein (MAG) in LAMP1+perinuclear vesicles that fail to migrate to the nascent myelin sheet. Live-cell imaging of OLs after genetic or pharmacological inhibition of PI(3,5)P2 synthesis revealed impaired trafficking of plasma membrane-derived MAG through the endolysosomal system in primary cells and brain tissue. Collectively, our studies identify PI(3,5)P2 as a key regulator of myelin membrane trafficking and myelinogenesis. DOI:http://dx.doi.org/10.7554/eLife.13023.001 Neurons communicate with each other through long cable-like extensions called axons. An insulating sheath called myelin (or white matter) surrounds each axon, and allows electrical impulses to travel more quickly. Cells in the brain called oligodendrocytes produce myelin. If the myelin sheath is not properly formed during development, or is damaged by injury or disease, the consequences can include paralysis, impaired thought, and loss of vision. Oligodendrocytes have complex shapes, and each can generate myelin for as many as 50 axons. Oligodendrocytes produce the building blocks of myelin inside their cell bodies, by following instructions encoded by genes within the nucleus. However, the signals that regulate the trafficking of these components to the myelin sheath are poorly understood. Mironova et al. set out to determine whether signaling molecules called phosphoinositides help oligodendrocytes to mature and move myelin building blocks from the cell bodies to remote contact points with axons. Genetic techniques were used to manipulate an enzyme complex in mice that controls the production and turnover of a phosphoinositide called PI(3,5)P2. Mironova et al. found that reducing the levels of PI(3,5)P2 in oligodendrocytes caused the trafficking of certain myelin building blocks to stall. Key myelin components instead accumulated inside bubble-like structures near the oligodendrocyte’s cell body. This showed that PI(3,5)P2 in oligodendrocytes is essential for generating myelin. Further experiments then revealed that reducing PI(3,5)P2 in the neurons themselves indirectly prevented the oligodendrocytes from maturing. This suggests that PI(3,5)P2 also takes part in communication between axons and oligodendrocytes during development of the myelin sheath. A key next step will be to identify the regulatory mechanisms that control the production of PI(3,5)P2 in oligodendrocytes and neurons. Future studies could also explore what PI(3,5)P2 acts upon inside the axons, and which signaling molecules support the maturation of oligodendrocytes. Finally, it remains unclear whether PI(3,5)P2signaling is also required for stabilizing mature myelin, and for repairing myelin after injury in the adult brain. Further work could therefore address these questions as well. DOI:http://dx.doi.org/10.7554/eLife.13023.002
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Affiliation(s)
- Yevgeniya A Mironova
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, United States.,Cellular and Molecular Biology Graduate Program, University of Michigan School of Medicine, Ann Arbor, United States
| | - Guy M Lenk
- Department of Human Genetics, University of Michigan School of Medicine, Ann Arbor, United States
| | - Jing-Ping Lin
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, United States
| | - Seung Joon Lee
- Department of Biological Sciences, University of South Carolina, Columbia, United States
| | - Jeffery L Twiss
- Department of Biological Sciences, University of South Carolina, Columbia, United States
| | - Ilaria Vaccari
- Human Inherited Neuropathies Unit, INSPE-Institute for Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
| | - Alessandra Bolino
- Human Inherited Neuropathies Unit, INSPE-Institute for Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
| | - Leif A Havton
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, United States
| | - Sang H Min
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, United States
| | - Charles S Abrams
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, United States
| | - Peter Shrager
- Department of Neurobiology and Anatomy, University of Rochester Medical Center, Rochester, United States
| | - Miriam H Meisler
- Department of Human Genetics, University of Michigan School of Medicine, Ann Arbor, United States.,Department of Neurology, University of Michigan School of Medicine, Ann Arbor, United States
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, United States.,Department of Neurology, University of Michigan School of Medicine, Ann Arbor, United States
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13
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Jarjour AA, Boyd A, Dow LE, Holloway RK, Goebbels S, Humbert PO, Williams A, ffrench-Constant C. The polarity protein Scribble regulates myelination and remyelination in the central nervous system. PLoS Biol 2015; 13:e1002107. [PMID: 25807062 PMCID: PMC4373955 DOI: 10.1371/journal.pbio.1002107] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 02/12/2015] [Indexed: 01/05/2023] Open
Abstract
The development and regeneration of myelin by oligodendrocytes, the myelin-forming cells of the central nervous system (CNS), requires profound changes in cell shape that lead to myelin sheath initiation and formation. Here, we demonstrate a requirement for the basal polarity complex protein Scribble in CNS myelination and remyelination. Scribble is expressed throughout oligodendroglial development and is up-regulated in mature oligodendrocytes where it is localised to both developing and mature CNS myelin sheaths. Knockdown of Scribble expression in cultured oligodendroglia results in disrupted morphology and myelination initiation. When Scribble expression is conditionally eliminated in the myelinating glia of transgenic mice, myelin initiation in CNS is disrupted, both during development and following focal demyelination, and longitudinal extension of the myelin sheath is disrupted. At later stages of myelination, Scribble acts to negatively regulate myelin thickness whilst suppressing the extracellular signal-related kinase (ERK)/mitogen-activated protein kinase (MAP) kinase pathway, and localises to non-compact myelin flanking the node of Ranvier where it is required for paranodal axo-glial adhesion. These findings demonstrate an essential role for the evolutionarily-conserved regulators of intracellular polarity in myelination and remyelination. The polarity protein Scribble regulates the formation and properties of myelin sheaths in the central nervous system during development and after demyelinating injury. The formation of myelin, a fatty, multilayered structure that surrounds certain neuronal axons in the nervous system, is essential for the proper communication of electrical signals by neurons, acting both as an insulator and to promote metabolic support to the axon. Loss of myelin can have severe functional consequences and trigger serious diseases, such as multiple sclerosis. Bidirectional communication between the oligodendrocytes, the myelinating cells of the central nervous system, and the axon is essential for the proper formation and function of myelin membranes; however, the signals that control myelination by oligodendrocytes in the central nervous system are poorly understood. In this paper, we use a combination of cell culture and animal studies to demonstrate that the protein Scribble, which is known to be a highly evolutionarily conserved regulator of cell polarity, plays a role in controlling whether oligodendrocytes myelinate axons. We show that Scribble regulates the length and thickness of myelin sheaths formed, as well as the tight adhesion of oligodendroglial membranes to the axonal surface, which is required for the organization of the axon into specialized domains at the nodes of Ranvier (gaps formed between the myelin sheaths generated by different cells). In addition, we show that Scribble plays a key role in the repair of myelin sheaths in a mouse model of demyelinating disease. The discovery of novel regulators of myelination in the central nervous system may allow for the identification of novel therapeutic targets for the promotion of myelin repair in patients suffering from demyelinating diseases.
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Affiliation(s)
- Andrew A. Jarjour
- MRC Centre for Regenerative Medicine and MS Society/University of Edinburgh Centre for Translational Research, Scottish Centre for Regenerative Medicine, The University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
| | - Amanda Boyd
- MRC Centre for Regenerative Medicine and MS Society/University of Edinburgh Centre for Translational Research, Scottish Centre for Regenerative Medicine, The University of Edinburgh, Edinburgh, United Kingdom
| | - Lukas E. Dow
- Cell Cycle and Cancer Genetics Laboratory, Peter MacCallum Cancer Centre, St Andrews Place, East Melbourne, Australia
| | - Rebecca K. Holloway
- MRC Centre for Regenerative Medicine and MS Society/University of Edinburgh Centre for Translational Research, Scottish Centre for Regenerative Medicine, The University of Edinburgh, Edinburgh, United Kingdom
| | - Sandra Goebbels
- Max Planck Institute for Experimental Medicine, Göttingen, Germany
| | - Patrick O. Humbert
- Cell Cycle and Cancer Genetics Laboratory, Peter MacCallum Cancer Centre, St Andrews Place, East Melbourne, Australia
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia
- Department of Pathology, University of Melbourne, Parkville, Victoria, Australia
| | - Anna Williams
- MRC Centre for Regenerative Medicine and MS Society/University of Edinburgh Centre for Translational Research, Scottish Centre for Regenerative Medicine, The University of Edinburgh, Edinburgh, United Kingdom
| | - Charles ffrench-Constant
- MRC Centre for Regenerative Medicine and MS Society/University of Edinburgh Centre for Translational Research, Scottish Centre for Regenerative Medicine, The University of Edinburgh, Edinburgh, United Kingdom
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14
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Wong JH, Halliday GM, Kim WS. Exploring myelin dysfunction in multiple system atrophy. Exp Neurobiol 2014; 23:337-44. [PMID: 25548533 PMCID: PMC4276804 DOI: 10.5607/en.2014.23.4.337] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 10/15/2014] [Accepted: 10/15/2014] [Indexed: 11/19/2022] Open
Abstract
Multiple system atrophy (MSA) is a rare, yet fatal neurodegenerative disease that presents clinically with autonomic failure in combination with parkinsonism or cerebellar ataxia. MSA impacts on the autonomic nervous system affecting blood pressure, heart rate and bladder function, and the motor system affecting balance and muscle movement. The cause of MSA is unknown, no definitive risk factors have been identified, and there is no cure or effective treatment. The definitive pathology of MSA is the presence of α-synuclein aggregates in the brain and therefore MSA is classified as an α-synucleinopathy, together with Parkinson's disease and dementia with Lewy bodies. Although the molecular mechanisms of misfolding, fibrillation and aggregation of α-synuclein partly overlap with other α-synucleinopathies, the pathological pathway of MSA is unique in that the principal site for α-synuclein deposition is in the oligodendrocytes rather than the neurons. The sequence of pathological events of MSA is now recognized as abnormal protein redistributions in oligodendrocytes first, followed by myelin dysfunction and then neurodegeneration. Oligodendrocytes are responsible for the production and maintenance of myelin, the specialized lipid membrane that encases the axons of all neurons in the brain. Myelin is composed of lipids and two prominent proteins, myelin basic protein and proteolipid protein. In vitro studies suggest that aberration in protein distribution and lipid transport may lead to myelin dysfunction in MSA. The purpose of this perspective is to bring together available evidence to explore the potential role of α-synuclein, myelin protein dysfunction, lipid dyshomeostasis and ABCA8 in MSA pathogenesis.
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Affiliation(s)
- Joanna H Wong
- Neuroscience Research Australia, Sydney, NSW 2031, Australia. ; School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Glenda M Halliday
- Neuroscience Research Australia, Sydney, NSW 2031, Australia. ; School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Woojin Scott Kim
- Neuroscience Research Australia, Sydney, NSW 2031, Australia. ; School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia
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15
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The major myelin-resident protein PLP is transported to myelin membranes via a transcytotic mechanism: involvement of sulfatide. Mol Cell Biol 2014; 35:288-302. [PMID: 25368380 DOI: 10.1128/mcb.00848-14] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Myelin membranes are sheet-like extensions of oligodendrocytes that can be considered membrane domains distinct from the cell's plasma membrane. Consistent with the polarized nature of oligodendrocytes, we demonstrate that transcytotic transport of the major myelin-resident protein proteolipid protein (PLP) is a key element in the mechanism of myelin assembly. Upon biosynthesis, PLP traffics to myelin membranes via syntaxin 3-mediated docking at the apical-surface-like cell body plasma membrane, which is followed by subsequent internalization and transport to the basolateral-surface-like myelin sheet. Pulse-chase experiments, in conjunction with surface biotinylation and organelle fractionation, reveal that following biosynthesis, PLP is transported to the cell body surface in Triton X-100 (TX-100)-resistant microdomains. At the plasma membrane, PLP transiently resides within these microdomains and its lateral dissipation is followed by segregation into 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate (CHAPS)-resistant domains, internalization, and subsequent transport toward the myelin membrane. Sulfatide triggers PLP's reallocation from TX-100- into CHAPS-resistant membrane domains, while inhibition of sulfatide biosynthesis inhibits transcytotic PLP transport. Taking these findings together, we propose a model in which PLP transport to the myelin membrane proceeds via a transcytotic mechanism mediated by sulfatide and characterized by a conformational alteration and dynamic, i.e., transient, partitioning of PLP into distinct membrane microdomains involved in biosynthetic and transcytotic transport.
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16
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Lipids in the nervous system: from biochemistry and molecular biology to patho-physiology. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1851:51-60. [PMID: 25150974 DOI: 10.1016/j.bbalip.2014.08.011] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 08/08/2014] [Accepted: 08/12/2014] [Indexed: 12/16/2022]
Abstract
Lipids in the nervous system accomplish a great number of key functions, from synaptogenesis to impulse conduction, and more. Most of the lipids of the nervous system are localized in myelin sheaths. It has long been known that myelin structure and brain homeostasis rely on specific lipid-protein interactions and on specific cell-to-cell signaling. In more recent years, the growing advances in large-scale technologies and genetically modified animal models have provided valuable insights into the role of lipids in the nervous system. Key findings recently emerged in these areas are here summarized. In addition, we briefly discuss how this new knowledge can open novel approaches for the treatment of diseases associated with alteration of lipid metabolism/homeostasis in the nervous system. This article is part of a Special Issue entitled Linking transcription to physiology in lipidomics.
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17
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Ozgen H, Schrimpf W, Hendrix J, de Jonge JC, Lamb DC, Hoekstra D, Kahya N, Baron W. The lateral membrane organization and dynamics of myelin proteins PLP and MBP are dictated by distinct galactolipids and the extracellular matrix. PLoS One 2014; 9:e101834. [PMID: 25003183 PMCID: PMC4086962 DOI: 10.1371/journal.pone.0101834] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 06/12/2014] [Indexed: 01/03/2023] Open
Abstract
In the central nervous system, lipid-protein interactions are pivotal for myelin maintenance, as these interactions regulate protein transport to the myelin membrane as well as the molecular organization within the sheath. To improve our understanding of the fundamental properties of myelin, we focused here on the lateral membrane organization and dynamics of peripheral membrane protein 18.5-kDa myelin basic protein (MBP) and transmembrane protein proteolipid protein (PLP) as a function of the typical myelin lipids galactosylceramide (GalC), and sulfatide, and exogenous factors such as the extracellular matrix proteins laminin-2 and fibronectin, employing an oligodendrocyte cell line, selectively expressing the desired galactolipids. The dynamics of MBP were monitored by z-scan point fluorescence correlation spectroscopy (FCS) and raster image correlation spectroscopy (RICS), while PLP dynamics in living cells were investigated by circular scanning FCS. The data revealed that on an inert substrate the diffusion rate of 18.5-kDa MBP increased in GalC-expressing cells, while the diffusion coefficient of PLP was decreased in sulfatide-containing cells. Similarly, when cells were grown on myelination-promoting laminin-2, the lateral diffusion coefficient of PLP was decreased in sulfatide-containing cells. In contrast, PLP's diffusion rate increased substantially when these cells were grown on myelination-inhibiting fibronectin. Additional biochemical analyses revealed that the observed differences in lateral diffusion coefficients of both proteins can be explained by differences in their biophysical, i.e., galactolipid environment, specifically with regard to their association with lipid rafts. Given the persistence of pathological fibronectin aggregates in multiple sclerosis lesions, this fundamental insight into the nature and dynamics of lipid-protein interactions will be instrumental in developing myelin regenerative strategies.
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Affiliation(s)
- Hande Ozgen
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Waldemar Schrimpf
- Physical Chemistry, Department of Chemistry, Munich Center for Integrated Protein Science (CiPSM) and Center for Nanoscience (CeNS), Ludwig-Maximilians-Universität, Munich, Germany
| | - Jelle Hendrix
- Physical Chemistry, Department of Chemistry, Munich Center for Integrated Protein Science (CiPSM) and Center for Nanoscience (CeNS), Ludwig-Maximilians-Universität, Munich, Germany
| | - Jenny C. de Jonge
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Don C. Lamb
- Physical Chemistry, Department of Chemistry, Munich Center for Integrated Protein Science (CiPSM) and Center for Nanoscience (CeNS), Ludwig-Maximilians-Universität, Munich, Germany
| | - Dick Hoekstra
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Nicoletta Kahya
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- * E-mail: (NK) (WB)
| | - Wia Baron
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- * E-mail: (NK) (WB)
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18
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Tanaka M, Izawa T, Yamate J, Franklin RJM, Kuramoto T, Serikawa T, Kuwamura M. The VF rat with abnormal myelinogenesis has a mutation in Dopey1. Glia 2014; 62:1530-42. [PMID: 24863653 DOI: 10.1002/glia.22698] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 04/30/2014] [Accepted: 05/07/2014] [Indexed: 11/09/2022]
Abstract
The vacuole formation (VF) rat is an autosomal recessive myelin mutant characterized by generalized tremor, hypomyelination, and periaxonal vacuole formation of the central nervous system (CNS). Here, we report the most likely causative gene for neurological disease in the VF rat and pursue its roles in the development and maintenance of the CNS myelin. We identified a nonsense mutation in the dopey family member 1 (Dopey1) located on rat chromosome 8. Expression level of Dopey1 mRNA was decreased and DOPEY1 protein was undetectable both in the white and gray matter of the spinal cords in the VF rats. Double immunohistochemistry demonstrated that DOPEY1 was mainly expressed in neurons and oligodendrocytes in the wild-type rats, whereas no positive cells were detected in the VF rats. We also demonstrated a marked reduction in myelin components both at mRNA and protein levels during myelinogenesis in the VF rats. In addition, proteolipid protein and myelin-associated glycoprotein accumulated in oligodendrocyte cell body, suggesting that Dopey1 is likely to be involved in the traffic of myelin components. Our results highlighted the importance of Dopey1 for the development and maintenance of the CNS myelin.
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Affiliation(s)
- Miyuu Tanaka
- Laboratory of Veterinary Pathology, Osaka Prefecture University, Izumisano, Osaka, 598-8531, Japan
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19
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Baron W, Bijlard M, Nomden A, de Jonge JC, Teunissen CE, Hoekstra D. Sulfatide-mediated control of extracellular matrix-dependent oligodendrocyte maturation. Glia 2014; 62:927-42. [DOI: 10.1002/glia.22650] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 01/08/2014] [Accepted: 02/05/2014] [Indexed: 01/16/2023]
Affiliation(s)
- Wia Baron
- Department of Cell Biology; University of Groningen, University Medical Center Groningen; Groningen The Netherlands
| | - Marjolein Bijlard
- Department of Cell Biology; University of Groningen, University Medical Center Groningen; Groningen The Netherlands
| | - Anita Nomden
- Department of Cell Biology; University of Groningen, University Medical Center Groningen; Groningen The Netherlands
| | - Jenny C. de Jonge
- Department of Cell Biology; University of Groningen, University Medical Center Groningen; Groningen The Netherlands
| | - Charlotte E. Teunissen
- Neurochemistry Laboratory and Biobank; Department of Clinical Chemistry; Neuroscience Campus Amsterdam; VU University Medical Center Amsterdam; Amsterdam The Netherlands
| | - Dick Hoekstra
- Department of Cell Biology; University of Groningen, University Medical Center Groningen; Groningen The Netherlands
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20
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Mwansisya TE, Wang Z, Tao H, Zhang H, Hu A, Guo S, Liu Z. The diminished interhemispheric connectivity correlates with negative symptoms and cognitive impairment in first-episode schizophrenia. Schizophr Res 2013; 150:144-50. [PMID: 23920057 DOI: 10.1016/j.schres.2013.07.018] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2013] [Revised: 06/17/2013] [Accepted: 07/06/2013] [Indexed: 01/22/2023]
Abstract
BACKGROUND Previous studies imply that interhemispheric disconnectivity plays a more important role on information processing in schizophrenia. However, the role of the aberrant interhemispheric connection in the pathophysiology of this disorder remains unclear. Recently, resting-state functional Magnetic Resonance Imaging (fMRI) has reported to have potentials of mapping functional interactions between pairs of brain hemispheres. METHODS Resting-state whole-brain functional connectivity analyses were performed on 41 schizophrenia patients and 33 healthy controls. RESULTS The first-episode schizophrenia patients showed significant aberrant interhemispheric connection in the globus pallidus, medial frontal gyrus and inferior temporal gyrus. The correlation of Wechsler Adult Intelligence Scale scores with odds ratio of the aberrant interhemispheric connections revealed positive correlation in the pallidum (rho=0.335, p=.003) and medial frontal gyrus (rho=0.260, p=.025). The connection in the pallidum was also positively correlated with duration of illness (rho=-0.407, p=.009). Whereas, the aberrant interhemispheric connection in the inferior temporal gyrus was positively correlated with scores of Scale for the Assessment of Negative Symptoms (rho=0.393, p=.012). CONCLUSION The present study provides fMRI evidence for the aberrant interhemispheric resting-state functional connectivity within resting-state networks in first-episode schizophrenia patients. These aberrant interhemispheric connections, in particular the pallidum, due to its anatomical and functional connectivities, may be the primary disturbance for cognitive impairment, negative symptoms and chronicity of schizophrenia.
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Affiliation(s)
- Tumbwene E Mwansisya
- Mental Health Institute of the Second Xiangya Hospital, Key Laboratory of Psychiatry and Mental Health of Hunan Province, Central South University, Changsha, Hunan 410011, China; College of Health Sciences, University of Dodoma, P.O Box 395, Dodoma, Tanzania
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21
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Camacho A, Huang JK, Delint-Ramirez I, Yew Tan C, Fuller M, Lelliott CJ, Vidal-Puig A, Franklin RJM. Peroxisome proliferator-activated receptor gamma-coactivator-1 alpha coordinates sphingolipid metabolism, lipid raft composition and myelin protein synthesis. Eur J Neurosci 2013; 38:2672-83. [DOI: 10.1111/ejn.12281] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 05/14/2013] [Accepted: 05/16/2013] [Indexed: 01/19/2023]
Affiliation(s)
- Alberto Camacho
- Metabolic Research Laboratories; Institute of Metabolic Science; Addenbrooke's Treatment Centre; Addenbrooke's Hospital; University of Cambridge; Cambridge; UK
| | - Jeffrey K. Huang
- Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute and Department of Veterinary Medicine; Cambridge; UK
| | - Ilse Delint-Ramirez
- Department of Pharmacology; Faculty of Medicine; Autonomous University of Nuevo León; Monterrey; Mexico
| | - Chong Yew Tan
- Metabolic Research Laboratories; Institute of Metabolic Science; Addenbrooke's Treatment Centre; Addenbrooke's Hospital; University of Cambridge; Cambridge; UK
| | - Maria Fuller
- Department of Genetics and Molecular Pathology; SA Pathology; Adelaide; SA; Australia
| | | | - Antonio Vidal-Puig
- Metabolic Research Laboratories; Institute of Metabolic Science; Addenbrooke's Treatment Centre; Addenbrooke's Hospital; University of Cambridge; Cambridge; UK
| | - Robin J. M. Franklin
- Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute and Department of Veterinary Medicine; Cambridge; UK
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Harauz G, Boggs JM. Myelin management by the 18.5-kDa and 21.5-kDa classic myelin basic protein isoforms. J Neurochem 2013; 125:334-61. [PMID: 23398367 DOI: 10.1111/jnc.12195] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 02/05/2013] [Accepted: 02/05/2013] [Indexed: 12/15/2022]
Abstract
The classic myelin basic protein (MBP) splice isoforms range in nominal molecular mass from 14 to 21.5 kDa, and arise from the gene in the oligodendrocyte lineage (Golli) in maturing oligodendrocytes. The 18.5-kDa isoform that predominates in adult myelin adheres the cytosolic surfaces of oligodendrocyte membranes together, and forms a two-dimensional molecular sieve restricting protein diffusion into compact myelin. However, this protein has additional roles including cytoskeletal assembly and membrane extension, binding to SH3-domains, participation in Fyn-mediated signaling pathways, sequestration of phosphoinositides, and maintenance of calcium homeostasis. Of the diverse post-translational modifications of this isoform, phosphorylation is the most dynamic, and modulates 18.5-kDa MBP's protein-membrane and protein-protein interactions, indicative of a rich repertoire of functions. In developing and mature myelin, phosphorylation can result in microdomain or even nuclear targeting of the protein, supporting the conclusion that 18.5-kDa MBP has significant roles beyond membrane adhesion. The full-length, early-developmental 21.5-kDa splice isoform is predominantly karyophilic due to a non-traditional P-Y nuclear localization signal, with effects such as promotion of oligodendrocyte proliferation. We discuss in vitro and recent in vivo evidence for multifunctionality of these classic basic proteins of myelin, and argue for a systematic evaluation of the temporal and spatial distributions of these protein isoforms, and their modified variants, during oligodendrocyte differentiation.
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Affiliation(s)
- George Harauz
- Department of Molecular and Cellular Biology, Biophysics Interdepartmental Group and Collaborative Program in Neuroscience, University of Guelph, Guelph, Ontario, Canada.
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Masaki T. Polarization and myelination in myelinating glia. ISRN NEUROLOGY 2012; 2012:769412. [PMID: 23326681 PMCID: PMC3544266 DOI: 10.5402/2012/769412] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 11/13/2012] [Indexed: 01/13/2023]
Abstract
Myelinating glia, oligodendrocytes in central nervous system and Schwann cells in peripheral nervous system, form myelin sheath, a multilayered membrane system around axons enabling salutatory nerve impulse conduction and maintaining axonal integrity. Myelin sheath is a polarized structure localized in the axonal side and therefore is supposed to be formed based on the preceding polarization of myelinating glia. Thus, myelination process is closely associated with polarization of myelinating glia. However, cell polarization has been less extensively studied in myelinating glia than other cell types such as epithelial cells. The ultimate goal of this paper is to provide insights for the field of myelination research by applying the information obtained in polarity study in other cell types, especially epithelial cells, to cell polarization of myelinating glia. Thus, in this paper, the main aspects of cell polarization study in general are summarized. Then, they will be compared with polarization in oligodendrocytes. Finally, the achievements obtained in polarization study for epithelial cells, oligodendrocytes, and other types of cells will be translated into polarization/myelination process by Schwann cells. Then, based on this model, the perspectives in the study of Schwann cell polarization/myelination will be discussed.
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Affiliation(s)
- Toshihiro Masaki
- Department of Medical Science, Teikyo University of Science, 2-2-1 Senju-Sakuragi, Adachi-ku, Tokyo 120-0045, Japan
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Smith GST, Samborska B, Hawley SP, Klaiman JM, Gillis TE, Jones N, Boggs JM, Harauz G. Nucleus-localized 21.5-kDa myelin basic protein promotes oligodendrocyte proliferation and enhances neurite outgrowth in coculture, unlike the plasma membrane-associated 18.5-kDa isoform. J Neurosci Res 2012. [PMID: 23184356 DOI: 10.1002/jnr.23166] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The classic myelin basic protein (MBP) family of central nervous system (CNS) myelin arises from transcription start site 3 of the Golli (gene of oligodendrocyte lineage) complex and comprises splice isoforms ranging in nominal molecular mass from 14 kDa to (full-length) 21.5 kDa. We have determined here a number of distinct functional differences between the major 18.5-kDa and minor 21.5-kDa isoforms of classic MBP with respect to oligodendrocyte (OLG) proliferation. We have found that, in contrast to 18.5-kDa MBP, 21.5-kDa MBP increases proliferation of early developmental immortalized N19-OLGs by elevating the levels of phosphorylated ERK1/2 and Akt1 kinases and of ribosomal protein S6. Coculture of N2a neuronal cells with N19-OLGs transfected with the 21.5-kDa isoform (or conditioned medium from), but not the 18.5-kDa isoform, caused the N2a cells to have increased neurite outgrowth and process branching complexity. These roles were dependent on subcellular localization of 21.5-kDa MBP to the nucleus and on the exon II-encoded segment, suggesting that the nuclear localization of early minor isoforms of MBP may play a crucial role in regulating and/or initiating myelin and neuronal development in the mammalian CNS.
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Affiliation(s)
- Graham S T Smith
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
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25
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Bucci C, Bakke O, Progida C. Charcot-Marie-Tooth disease and intracellular traffic. Prog Neurobiol 2012; 99:191-225. [PMID: 22465036 PMCID: PMC3514635 DOI: 10.1016/j.pneurobio.2012.03.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2011] [Revised: 12/23/2011] [Accepted: 03/13/2012] [Indexed: 12/23/2022]
Abstract
Mutations of genes whose primary function is the regulation of membrane traffic are increasingly being identified as the underlying causes of various important human disorders. Intriguingly, mutations in ubiquitously expressed membrane traffic genes often lead to cell type- or organ-specific disorders. This is particularly true for neuronal diseases, identifying the nervous system as the most sensitive tissue to alterations of membrane traffic. Charcot-Marie-Tooth (CMT) disease is one of the most common inherited peripheral neuropathies. It is also known as hereditary motor and sensory neuropathy (HMSN), which comprises a group of disorders specifically affecting peripheral nerves. This peripheral neuropathy, highly heterogeneous both clinically and genetically, is characterized by a slowly progressive degeneration of the muscle of the foot, lower leg, hand and forearm, accompanied by sensory loss in the toes, fingers and limbs. More than 30 genes have been identified as targets of mutations that cause CMT neuropathy. A number of these genes encode proteins directly or indirectly involved in the regulation of intracellular traffic. Indeed, the list of genes linked to CMT disease includes genes important for vesicle formation, phosphoinositide metabolism, lysosomal degradation, mitochondrial fission and fusion, and also genes encoding endosomal and cytoskeletal proteins. This review focuses on the link between intracellular transport and CMT disease, highlighting the molecular mechanisms that underlie the different forms of this peripheral neuropathy and discussing the pathophysiological impact of membrane transport genetic defects as well as possible future ways to counteract these defects.
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Affiliation(s)
- Cecilia Bucci
- Department of Biological and Environmental Sciences and Technologies (DiSTeBA), University of Salento, Via Provinciale Monteroni, 73100 Lecce, Italy.
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26
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Horiuchi M, Maezawa I, Itoh A, Wakayama K, Jin LW, Itoh T, DeCarli C. Amyloid β1-42 oligomer inhibits myelin sheet formation in vitro. Neurobiol Aging 2012; 33:499-509. [PMID: 20594620 PMCID: PMC3013291 DOI: 10.1016/j.neurobiolaging.2010.05.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Revised: 04/30/2010] [Accepted: 05/09/2010] [Indexed: 01/26/2023]
Abstract
Accumulating evidence indicates that white matter degeneration contributes to the neural disconnections that underlie Alzheimer's disease pathophysiology. Although this white matter degeneration is partly attributable to axonopathy associated with neuronal degeneration, amyloid β (Aβ) protein-mediated damage to oligodendrocytes could be another mechanism. To test this hypothesis, we studied effects of soluble Aβ in oligomeric form on survival and differentiation of cells of the oligodendroglial lineage using highly purified oligodendroglial cultures from rats at different developmental stages. Aβ oligomer at 10 μM or higher reduced survival of mature oligodendrocytes, whereas oligodendroglial progenitor cells (OPCs) were relatively resistant to the Aβ oligomer-mediated cytotoxicity. Further study revealed that Aβ oligomer even at 1 μM accelerated 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) formazan exocytosis in mature oligodendrocytes, and, more significantly, inhibited myelin sheet formation after induction of in vitro differentiation of OPCs. These results imply a novel pathogenetic mechanism underlying Aβ oligomer-mediated white matter degeneration, which could impair myelin maintenance and remyelination by adult OPCs, resulting in accumulating damage to myelinating axons thereby contributing to neural disconnections.
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Affiliation(s)
- Makoto Horiuchi
- Department of Neurology, University of California Davis, School of Medicine, Sacramento, CA, United States
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children Northern California, Sacramento, CA, United States
| | - Izumi Maezawa
- M.I.N.D. Institute and Department of Pathology, Department of Internal Medicine, University of California Davis Cancer Center, University of California Davis, Sacramento, CA, United States
| | - Aki Itoh
- Department of Neurology, University of California Davis, School of Medicine, Sacramento, CA, United States
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children Northern California, Sacramento, CA, United States
| | - Kouji Wakayama
- Department of Neurology, University of California Davis, School of Medicine, Sacramento, CA, United States
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children Northern California, Sacramento, CA, United States
| | - Lee-Way Jin
- M.I.N.D. Institute and Department of Pathology, Department of Internal Medicine, University of California Davis Cancer Center, University of California Davis, Sacramento, CA, United States
| | - Takayuki Itoh
- Department of Neurology, University of California Davis, School of Medicine, Sacramento, CA, United States
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children Northern California, Sacramento, CA, United States
| | - Charles DeCarli
- Department of Neurology, University of California Davis, School of Medicine, Sacramento, CA, United States
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Smith GST, Homchaudhuri L, Boggs JM, Harauz G. Classic 18.5- and 21.5-kDa myelin basic protein isoforms associate with cytoskeletal and SH3-domain proteins in the immortalized N19-oligodendroglial cell line stimulated by phorbol ester and IGF-1. Neurochem Res 2012; 37:1277-95. [PMID: 22249765 DOI: 10.1007/s11064-011-0700-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Revised: 11/17/2011] [Accepted: 12/31/2011] [Indexed: 01/10/2023]
Abstract
The 18.5-kDa classic myelin basic protein (MBP) is an intrinsically disordered protein arising from the Golli (Genes of Oligodendrocyte Lineage) gene complex and is responsible for compaction of the myelin sheath in the central nervous system. This MBP splice isoform also has a plethora of post-translational modifications including phosphorylation, deimination, methylation, and deamidation, that reduce its overall net charge and alter its protein and lipid associations within oligodendrocytes (OLGs). It was originally thought that MBP was simply a structural component of myelin; however, additional investigations have demonstrated that MBP is multi-functional, having numerous protein-protein interactions with Ca²⁺-calmodulin, actin, tubulin, and proteins with SH3-domains, and it can tether these proteins to a lipid membrane in vitro. Here, we have examined cytoskeletal interactions of classic 18.5-kDa MBP, in vivo, using early developmental N19-OLGs transfected with fluorescently-tagged MBP, actin, tubulin, and zonula occludens 1 (ZO-1). We show that MBP redistributes to distinct 'membrane-ruffled' regions of the plasma membrane where it co-localizes with actin and tubulin, and with the SH3-domain-containing proteins cortactin and ZO-1, when stimulated with PMA, a potent activator of the protein kinase C pathway. Moreover, using phospho-specific antibody staining, we show an increase in phosphorylated Thr98 MBP (human sequence numbering) in membrane-ruffled OLGs. Previously, Thr98 phosphorylation of MBP has been shown to affect its conformation, interactions with other proteins, and tethering of other proteins to the membrane in vitro. Here, MBP and actin were also co-localized in new focal adhesion contacts induced by IGF-1 stimulation in cells grown on laminin-2. This study supports a role for classic MBP isoforms in cytoskeletal and other protein-protein interactions during membrane and cytoskeletal remodeling in OLGs.
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Affiliation(s)
- Graham S T Smith
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
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28
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Bello-Morales R, Pérez-Hernández M, Rejas MT, Matesanz F, Alcina A, López-Guerrero JA. Interaction of PLP with GFP-MAL2 in the human oligodendroglial cell line HOG. PLoS One 2011; 6:e19388. [PMID: 21573057 PMCID: PMC3090389 DOI: 10.1371/journal.pone.0019388] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 03/28/2011] [Indexed: 11/18/2022] Open
Abstract
The velocity of the nerve impulse conduction of vertebrates relies on the myelin sheath, an electrically insulating layer that surrounds axons in both the central and peripheral nervous systems, enabling saltatory conduction of the action potential. Oligodendrocytes are the myelin-producing glial cells in the central nervous system. A deeper understanding of the molecular basis of myelination and, specifically, of the transport of myelin proteins, will contribute to the search of the aetiology of many dysmyelinating and demyelinating diseases, including multiple sclerosis. Recent investigations suggest that proteolipid protein (PLP), the major myelin protein, could reach myelin sheath by an indirect transport pathway, that is, a transcytotic route via the plasma membrane of the cell body. If PLP transport relies on a transcytotic process, it is reasonable to consider that this myelin protein could be associated with MAL2, a raft protein essential for transcytosis. In this study, carried out with the human oligodendrocytic cell line HOG, we show that PLP colocalized with green fluorescent protein (GFP)-MAL2 after internalization from the plasma membrane. In addition, both immunoprecipitation and immunofluorescence assays, indicated the existence of an interaction between GFP-MAL2 and PLP. Finally, ultrastructural studies demonstrated colocalization of GFP-MAL2 and PLP in vesicles and tubulovesicular structures. Taken together, these results prove for the first time the interaction of PLP and MAL2 in oligodendrocytic cells, supporting the transcytotic model of PLP transport previously suggested.
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Affiliation(s)
- Raquel Bello-Morales
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid/Consejo Superior de Investigaciones Científicas, Cantoblanco, Madrid, Spain
| | - Marta Pérez-Hernández
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid/Consejo Superior de Investigaciones Científicas, Cantoblanco, Madrid, Spain
| | - María Teresa Rejas
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid/Consejo Superior de Investigaciones Científicas, Cantoblanco, Madrid, Spain
| | - Fuencisla Matesanz
- Instituto de Parasitología y Biomedicina “López-Neyra”, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Antonio Alcina
- Instituto de Parasitología y Biomedicina “López-Neyra”, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - José Antonio López-Guerrero
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid/Consejo Superior de Investigaciones Científicas, Cantoblanco, Madrid, Spain
- * E-mail:
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29
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Myelin Restoration: Progress and Prospects for Human Cell Replacement Therapies. Arch Immunol Ther Exp (Warsz) 2011; 59:179-93. [DOI: 10.1007/s00005-011-0120-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Accepted: 11/17/2010] [Indexed: 12/12/2022]
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30
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Smith GST, Paez PM, Spreuer V, Campagnoni CW, Boggs JM, Campagnoni AT, Harauz G. Classical 18.5-and 21.5-kDa isoforms of myelin basic protein inhibit calcium influx into oligodendroglial cells, in contrast to golli isoforms. J Neurosci Res 2011; 89:467-80. [PMID: 21312222 DOI: 10.1002/jnr.22570] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 11/02/2010] [Accepted: 11/04/2010] [Indexed: 11/10/2022]
Abstract
The myelin basic protein (MBP) family arises from different transcription start sites of the golli (gene of oligodendrocyte lineage) complex, with further variety generated by differential splicing. The "classical" MBP isoforms are peripheral membrane proteins that facilitate compaction of the mature myelin sheath but also have multiple protein interactions. The early developmental golli isoforms have previously been shown to promote process extension and enhance Ca(2+) influx into primary and immortalized oligodendrocyte cell lines. Here, we have performed similar studies with the classical 18.5- and 21.5-kDa isoforms of MBP. In contrast to golli proteins, overexpression of classical MBP isoforms significantly reduces Ca(2+) influx in the oligodendrocyte cell line N19 as well as in primary cultures of oligodendroglial progenitor cells. Pharmacological experiments demonstrate that this effect is mediated by voltage-operated Ca(2+) channels (VOCCs) and not by ligand-gated Ca(2+) channels or Ca(2+) release from intracellular stores. The pseudo-deiminated 18.5-kDa and the full-length 21.5-kDa isoforms do not reduce Ca(2+) influx as much as the unmodified 18.5-kDa isoform. However, more efficient membrane localization (of overexpressed, pseudo-deiminated 18.5-kDa and 21.5-kDa isoforms of classical MBP containing the 21-nt 3'-untranslated region transit signal) further reduces the Ca(2+) response after plasma membrane depolarization, suggesting that binding of classical MBP isoforms to the plasma membrane is important for modulation of Ca(2+) homeostasis. Furthermore, we have found that the mature 18.5-kDa isoform expressed in oligodendrocytes colocalizes with VOCCs, particularly at the leading edge of extending membrane processes. In summary, our findings suggest a key role for classical MBP proteins in regulating voltage-gated Ca(2+) channels at the plasma membrane of oligodendroglial cells and thus also in regulation of multiple developmental stages in this cell lineage.
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Affiliation(s)
- Graham S T Smith
- Department of Molecular and Cellular Biology, and Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario, Canada
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31
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Larson TA, Gordon TN, Lau HE, Parichy DM. Defective adult oligodendrocyte and Schwann cell development, pigment pattern, and craniofacial morphology in puma mutant zebrafish having an alpha tubulin mutation. Dev Biol 2010; 346:296-309. [PMID: 20692250 DOI: 10.1016/j.ydbio.2010.07.035] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Revised: 07/26/2010] [Accepted: 07/30/2010] [Indexed: 11/18/2022]
Abstract
The processes of myelination remain incompletely understood but are of profound biomedical importance owing to the several dysmyelinating and demyelinating disorders known in humans. Here, we analyze the zebrafish puma mutant, isolated originally for pigment pattern defects limited to the adult stage. We show that puma mutants also have late-arising defects in Schwann cells of the peripheral nervous system, locomotor abnormalities, and sex-biased defects in adult craniofacial morphology. Using methods of positional cloning, we identify a critical genetic interval harboring two alpha tubulin loci, and we identify a chemically induced missense mutation in one of these, tubulin alpha 8-like 3a (tuba8l3a). We demonstrate tuba8l3a expression in the central nervous system (CNS), leading us to search for defects in the development of oligodendrocytes, the myelinating cells of the CNS. We find gross reductions in CNS myelin and oligodendrocyte numbers in adult puma mutants, and these deficits are apparent already during the larval-to-adult transformation. By contrast, analyses of embryos and early larvae reveal a normal complement of oligodendrocytes that nevertheless fail to localize normal amounts of myelin basic protein (mbp) mRNA in cellular processes, and fail to organize these processes as in the wild-type. This study identifies the puma mutant as a valuable model for studying microtubule-dependent events of myelination, as well as strategies for remyelination in the adult.
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Affiliation(s)
- Tracy A Larson
- Department of Biology, Institute for Stem Cell and Regenerative Medicine, University of Washington, Box 351800, Seattle, WA 98195-1800, USA
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32
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Elevated phosphatidylinositol 3,4,5-trisphosphate in glia triggers cell-autonomous membrane wrapping and myelination. J Neurosci 2010; 30:8953-64. [PMID: 20592216 DOI: 10.1523/jneurosci.0219-10.2010] [Citation(s) in RCA: 253] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
In the developing nervous system, constitutive activation of the AKT/mTOR (mammalian target of rapamycin) pathway in myelinating glial cells is associated with hypermyelination of the brain, but is reportedly insufficient to drive myelination by Schwann cells. We have hypothesized that it requires additional mechanisms downstream of NRG1/ErbB signaling to trigger myelination in the peripheral nervous system. Here, we demonstrate that elevated levels of phosphatidylinositol 3,4,5-trisphosphate (PIP3) have developmental effects on both oligodendrocytes and Schwann cells. By generating conditional mouse mutants, we found that Pten-deficient Schwann cells are enhanced in number and can sort and myelinate axons with calibers well below 1 microm. Unexpectedly, mutant glial cells also spirally enwrap C-fiber axons within Remak bundles and even collagen fibrils, which lack any membrane surface. Importantly, PIP3-dependent hypermyelination of central axons, which is observed when targeting Pten in oligodendrocytes, can also be induced after tamoxifen-mediated Cre recombination in adult mice. We conclude that it requires distinct PIP3 effector mechanisms to trigger axonal wrapping. That myelin synthesis is not restricted to early development but can occur later in life is relevant to developmental disorders and myelin disease.
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Pals1 is a major regulator of the epithelial-like polarization and the extension of the myelin sheath in peripheral nerves. J Neurosci 2010; 30:4120-31. [PMID: 20237282 DOI: 10.1523/jneurosci.5185-09.2010] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Diameter, organization, and length of the myelin sheath are important determinants of the nerve conduction velocity, but the basic molecular mechanisms that control these parameters are only partially understood. Cell polarization is an essential feature of differentiated cells, and relies on a set of evolutionarily conserved cell polarity proteins. We investigated the molecular nature of myelin sheath polarization in connection with the functional role of the cell polarity protein pals1 (Protein Associated with Lin Seven 1) during peripheral nerve myelin sheath extension. We found that, in regard to epithelial polarity, the Schwann cell outer abaxonal domain represents a basolateral-like domain, while the inner adaxonal domain and Schmidt-Lanterman incisures form an apical-like domain. Silencing of pals1 in myelinating Schwann cells in vivo resulted in a severe reduction of myelin sheath thickness and length. Except for some infoldings, the structure of compact myelin was not fundamentally affected, but cells produced less myelin turns. In addition, pals1 is required for the normal polarized localization of the vesicular markers sec8 and syntaxin4, and for the distribution of E-cadherin and myelin proteins PMP22 and MAG at the plasma membrane. Our data show that the polarity protein pals1 plays an essential role in the radial and longitudinal extension of the myelin sheath, likely involving a functional role in membrane protein trafficking. We conclude that regulation of epithelial-like polarization is a critical determinant of myelin sheath structure and function.
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34
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Fumaric acid dialkyl esters deprive cultured rat oligodendroglial cells of glutathione and upregulate the expression of heme oxygenase 1. Neurosci Lett 2010; 475:56-60. [DOI: 10.1016/j.neulet.2010.03.048] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2010] [Revised: 03/10/2010] [Accepted: 03/18/2010] [Indexed: 11/17/2022]
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35
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Age- and brain region-specific effects of dietary vitamin K on myelin sulfatides. J Nutr Biochem 2010; 21:1083-8. [PMID: 20092997 DOI: 10.1016/j.jnutbio.2009.09.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Revised: 07/13/2009] [Accepted: 09/17/2009] [Indexed: 02/06/2023]
Abstract
Dysregulation of myelin sulfatides is a risk factor for cognitive decline with age. Vitamin K is present in high concentrations in the brain and has been implicated in the regulation of sulfatide metabolism. Our objective was to investigate the age-related interrelation between dietary vitamin K and sulfatides in myelin fractions isolated from the brain regions of Fischer 344 male rats fed one of two dietary forms of vitamin K: phylloquinone or its hydrogenated form, 2',3'-dihydrophylloquinone (dK), for 28 days. Both dietary forms of vitamin K were converted to menaquinone-4 (MK-4) in the brain. The efficiency of dietary dK conversion to MK-4 compared to dietary phylloquinone was lower in the striatum and cortex, and was similar to that in the hippocampus. There were significant positive correlations between sulfatides and MK-4 in the hippocampus (phylloquinone-supplemented diet, 12 and 24 months; dK-supplemented diet, 12 months) and cortex (phylloquinone-supplemented diet, 12 and 24 months). No significant correlations were observed in the striatum. Furthermore, sulfatides in the hippocampus were significantly positively correlated with MK-4 in serum. This is the first attempt to establish and characterize a novel animal model that exploits the inability of dietary dK to convert to brain MK-4 to study the dietary effects of vitamin K on brain sulfatide in brain regions controlling motor and cognitive functions. Our findings suggest that this animal model may be useful for investigation of the effect of the dietary vitamin K on sulfatide metabolism, myelin structure and behavior functions.
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36
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On the biogenesis of myelin membranes: sorting, trafficking and cell polarity. FEBS Lett 2009; 584:1760-70. [PMID: 19896485 DOI: 10.1016/j.febslet.2009.10.085] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Revised: 10/29/2009] [Accepted: 10/30/2009] [Indexed: 11/22/2022]
Abstract
In the central nervous system, a multilayered membrane layer known as the myelin sheath enwraps axons, and is required for optimal saltatory signal conductance. The sheath develops from membrane processes that extend from the plasma membrane of oligodendrocytes and displays a unique lipid and protein composition. Myelin biogenesis is carefully regulated, and multiple transport pathways involving a variety of endosomal compartments are involved. Here we briefly summarize how the major myelin proteins proteolipid protein and myelin basic protein reach the sheath, and highlight potential mechanisms involved, including the role of myelin specific lipids and cell polarity related transport pathways.
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37
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Bartzokis G. Alzheimer's disease as homeostatic responses to age-related myelin breakdown. Neurobiol Aging 2009; 32:1341-71. [PMID: 19775776 DOI: 10.1016/j.neurobiolaging.2009.08.007] [Citation(s) in RCA: 386] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2008] [Revised: 08/13/2009] [Accepted: 08/17/2009] [Indexed: 12/11/2022]
Abstract
The amyloid hypothesis (AH) of Alzheimer's disease (AD) posits that the fundamental cause of AD is the accumulation of the peptide amyloid beta (Aβ) in the brain. This hypothesis has been supported by observations that genetic defects in amyloid precursor protein (APP) and presenilin increase Aβ production and cause familial AD (FAD). The AH is widely accepted but does not account for important phenomena including recent failures of clinical trials to impact dementia in humans even after successfully reducing Aβ deposits. Herein, the AH is viewed from the broader overarching perspective of the myelin model of the human brain that focuses on functioning brain circuits and encompasses white matter and myelin in addition to neurons and synapses. The model proposes that the recently evolved and extensive myelination of the human brain underlies both our unique abilities and susceptibility to highly prevalent age-related neuropsychiatric disorders such as late onset AD (LOAD). It regards oligodendrocytes and the myelin they produce as being both critical for circuit function and uniquely vulnerable to damage. This perspective reframes key observations such as axonal transport disruptions, formation of axonal swellings/sphenoids and neuritic plaques, and proteinaceous deposits such as Aβ and tau as by-products of homeostatic myelin repair processes. It delineates empirically testable mechanisms of action for genes underlying FAD and LOAD and provides "upstream" treatment targets. Such interventions could potentially treat multiple degenerative brain disorders by mitigating the effects of aging and associated changes in iron, cholesterol, and free radicals on oligodendrocytes and their myelin.
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Affiliation(s)
- George Bartzokis
- Department of Psychiatry and Biobehavioral Sciences, The David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
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38
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Maier O, De Jonge J, Nomden A, Hoekstra D, Baron W. Lovastatin induces the formation of abnormal myelin-like membrane sheets in primary oligodendrocytes. Glia 2009; 57:402-13. [PMID: 18814266 DOI: 10.1002/glia.20769] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Statins, well-known inhibitors of cholesterol synthesis and protein isoprenylation, have been proposed as therapeutic drugs for multiple sclerosis (MS). As lovastatin and simvastatin, which are currently tested for their use in MS, can cross the blood-brain barrier, they may affect cellular processes in the central nervous system. This is especially relevant with respect to remyelination as a proposed additional treatment for MS, because cholesterol is a major component of myelin. Here, we show that primary oligodendrocytes, treated with lovastatin, form extensive membrane sheets, which contain galactosphingolipids. However, these membrane sheets are devoid of the major myelin proteins, myelin basic protein (MBP) and proteolipid protein (PLP). Reduced MBP protein expression was confirmed by SDS-PAGE and Western blotting, and in situ hybridization experiments revealed that lovastatin blocks MBP mRNA transport into oligodendrocyte processes. In contrast, PLP expression was only mildly affected by lovastatin. However, lovastatin treatment resulted in intracellular accumulation of PLP and prevented its translocation to the cell surface. Interestingly, another inhibitor of cholesterol synthesis (ro48-8071), which does not interfere with isoprenylation, had a similar effect on the localization of PLP, but it did not affect MBP expression and localization. These results suggest that lovastatin affects PLP transport predominantly by the inhibition of cholesterol synthesis, whereas reduced MBP expression is caused by impaired isoprenylation. Based on these results we recommend to carefully monitor the effect of statins on myelination prior to their use in demyelinating diseases.
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Affiliation(s)
- Olaf Maier
- Section of Membrane Cell Biology, Department of Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
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39
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Gudi V, Moharregh-Khiabani D, Skripuletz T, Koutsoudaki PN, Kotsiari A, Skuljec J, Trebst C, Stangel M. Regional differences between grey and white matter in cuprizone induced demyelination. Brain Res 2009; 1283:127-38. [PMID: 19524552 DOI: 10.1016/j.brainres.2009.06.005] [Citation(s) in RCA: 176] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Revised: 05/29/2009] [Accepted: 06/02/2009] [Indexed: 11/25/2022]
Abstract
Cuprizone feeding is a commonly used model to study experimental de- and remyelination, with the corpus callosum being the most frequently investigated white matter tract. We have previously shown that demyelination is also extensive in the cerebral cortex in the cuprizone model. In the current study, we have performed a detailed analysis of the dynamics of demyelination in the cortex in comparison to the corpus callosum. Prominent and almost complete demyelination in the corpus callosum was observed after 4.5-5 weeks of 0.2% cuprizone feeding, whereas complete cortical demyelination was only observed after 6 weeks of cuprizone feeding. Interestingly, remyelination in the corpus callosum occurred even before the termination of cuprizone administration. Accumulation of microglia in the corpus callosum started as early as week 3 reaching its maximum at week 4.5 and was still significantly elevated at week 6 of cuprizone treatment. Within the cortex only a few scattered activated microglial cells were found. Furthermore, the intensity of astrogliosis, accumulation of oligodendrocyte progenitor cells and nestin positive cells differed between the two areas investigated. The time course and dynamics of demyelination differ in the corpus callosum and in the cortex, suggesting different underlying pathomechanisms.
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Affiliation(s)
- Viktoria Gudi
- Department of Neurology, Hannover Medical School, Hannover, Germany
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40
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Feldmann A, Winterstein C, White R, Trotter J, Krämer-Albers EM. Comprehensive analysis of expression, subcellular localization, and cognate pairing of SNARE proteins in oligodendrocytes. J Neurosci Res 2009; 87:1760-72. [DOI: 10.1002/jnr.22020] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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41
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Current World Literature. Curr Opin Neurol 2009; 22:321-9. [DOI: 10.1097/wco.0b013e32832cf9cb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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42
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Epithelial cell–cell junctions and plasma membrane domains. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:820-31. [DOI: 10.1016/j.bbamem.2008.07.015] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Revised: 07/10/2008] [Accepted: 07/21/2008] [Indexed: 12/16/2022]
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43
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Etienne-Manneville S. Polarity proteins in glial cell functions. Curr Opin Neurobiol 2008; 18:488-94. [PMID: 18840525 DOI: 10.1016/j.conb.2008.09.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2008] [Revised: 09/18/2008] [Accepted: 09/24/2008] [Indexed: 12/31/2022]
Abstract
Glial cells, which include myelinating oligodendrocytes, Schwann cells and astrocytes, fulfil a large variety of functions that are critical for the development, functioning and regeneration of neurons. Some of these glial functions have been shown to require polarization of the intracellular machinery. Although the initial signals leading to glial cell polarization during development and in the adult are not completely elucidated, crucial molecules such as proteins of the extracellular matrix and their membrane receptors have been identified. A general picture of the intracellular signalling pathways controlling polarity in glial cells is also emerging and shows that highly conserved and ubiquitously expressed polarity proteins are involved.
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The ubiquitin-proteasome system in spongiform degenerative disorders. Biochim Biophys Acta Mol Basis Dis 2008; 1782:700-12. [PMID: 18790052 PMCID: PMC2612938 DOI: 10.1016/j.bbadis.2008.08.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Revised: 08/13/2008] [Accepted: 08/15/2008] [Indexed: 12/20/2022]
Abstract
Spongiform degeneration is characterized by vacuolation in nervous tissue accompanied by neuronal death and gliosis. Although spongiform degeneration is a hallmark of prion diseases, this pathology is also present in the brains of patients suffering from Alzheimer’s disease, diffuse Lewy body disease, human immunodeficiency virus (HIV) infection, and Canavan’s spongiform leukodystrophy. The shared outcome of spongiform degeneration in these diverse diseases suggests that common cellular mechanisms must underlie the processes of spongiform change and neurodegeneration in the central nervous system. Immunohistochemical analysis of brain tissues reveals increased ubiquitin immunoreactivity in and around areas of spongiform change, suggesting the involvement of ubiquitin–proteasome system dysfunction in the pathogenesis of spongiform neurodegeneration. The link between aberrant ubiquitination and spongiform neurodegeneration has been strengthened by the discovery that a null mutation in the E3 ubiquitin–protein ligase mahogunin ring finger-1 (Mgrn1) causes an autosomal recessively inherited form of spongiform neurodegeneration in animals. Recent studies have begun to suggest that abnormal ubiquitination may alter intracellular signaling and cell functions via proteasome-dependent and proteasome-independent mechanisms, leading to spongiform degeneration and neuronal cell death. Further elucidation of the pathogenic pathways involved in spongiform neurodegeneration should facilitate the development of novel rational therapies for treating prion diseases, HIV infection, and other spongiform degenerative disorders.
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