1
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Bagheri H, Friedman H, Hadwen A, Jarweh C, Cooper E, Oprea L, Guerrier C, Khadra A, Collin A, Cohen-Adad J, Young A, Victoriano GM, Swire M, Jarjour A, Bechler ME, Pryce RS, Chaurand P, Cougnaud L, Vuckovic D, Wilion E, Greene O, Nishiyama A, Benmamar-Badel A, Owens T, Grouza V, Tuznik M, Liu H, Rudko DA, Zhang J, Siminovitch KA, Peterson AC. Myelin basic protein mRNA levels affect myelin sheath dimensions, architecture, plasticity, and density of resident glial cells. Glia 2024; 72:1893-1914. [PMID: 39023138 DOI: 10.1002/glia.24589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2024] [Revised: 05/29/2024] [Accepted: 06/23/2024] [Indexed: 07/20/2024]
Abstract
Myelin Basic Protein (MBP) is essential for both elaboration and maintenance of CNS myelin, and its reduced accumulation results in hypomyelination. How different Mbp mRNA levels affect myelin dimensions across the lifespan and how resident glial cells may respond to such changes are unknown. Here, to investigate these questions, we used enhancer-edited mouse lines that accumulate Mbp mRNA levels ranging from 8% to 160% of wild type. In young mice, reduced Mbp mRNA levels resulted in corresponding decreases in Mbp protein accumulation and myelin sheath thickness, confirming the previously demonstrated rate-limiting role of Mbp transcription in the control of initial myelin synthesis. However, despite maintaining lower line specific Mbp mRNA levels into old age, both MBP protein levels and myelin thickness improved or fully normalized at rates defined by the relative Mbp mRNA level. Sheath length, in contrast, was affected only when mRNA levels were very low, demonstrating that sheath thickness and length are not equally coupled to Mbp mRNA level. Striking abnormalities in sheath structure also emerged with reduced mRNA levels. Unexpectedly, an increase in the density of all glial cell types arose in response to reduced Mbp mRNA levels. This investigation extends understanding of the role MBP plays in myelin sheath elaboration, architecture, and plasticity across the mouse lifespan and illuminates a novel axis of glial cell crosstalk.
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Affiliation(s)
- Hooman Bagheri
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - Hana Friedman
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - Amanda Hadwen
- Department of Physiology, McGill University, Montreal, Quebec, Canada
| | - Celia Jarweh
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Ellis Cooper
- Department of Physiology, McGill University, Montreal, Quebec, Canada
| | - Lawrence Oprea
- Integrated Program in Neuroscience, McGill University, Montréal, Quebec, Canada
| | | | - Anmar Khadra
- Integrated Program in Neuroscience, McGill University, Montréal, Quebec, Canada
| | - Armand Collin
- Institute of Biomedical Engineering, Ecole Polytechnique de Montreal, Montreal, Quebec, Canada
| | - Julien Cohen-Adad
- Institute of Biomedical Engineering, Ecole Polytechnique de Montreal, Montreal, Quebec, Canada
| | - Amanda Young
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Gerardo Mendez Victoriano
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Matthew Swire
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Andrew Jarjour
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Marie E Bechler
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Rachel S Pryce
- Department of Chemistry, Université de Montréal, Montreal, Quebec, Canada
| | - Pierre Chaurand
- Department of Chemistry, Université de Montréal, Montreal, Quebec, Canada
| | - Lise Cougnaud
- Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec, Canada
| | - Dajana Vuckovic
- Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec, Canada
| | - Elliott Wilion
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Owen Greene
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Akiko Nishiyama
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
- Institute for Systems Genomics, University of Connecticut, Storrs, Connecticut, USA
- The Connecticut Institute for Brain and Cognitive Sciences, University of Connecticut, Storrs, Connecticut, USA
| | - Anouk Benmamar-Badel
- Department of Neurobiology Research, Institute for Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Trevor Owens
- Department of Neurobiology Research, Institute for Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Vladimir Grouza
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - Marius Tuznik
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - Hanwen Liu
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - David A Rudko
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
- Department of Biomedical Engineering, McGill University, Montreal, Quebec, Canada
| | - Jinyi Zhang
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
- Mount Sinai Hospital, Lunenfeld-Tanenbaum and Toronto General Hospital Research Institutes, Toronto, Ontario, Canada
| | - Katherine A Siminovitch
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
- Mount Sinai Hospital, Lunenfeld-Tanenbaum and Toronto General Hospital Research Institutes, Toronto, Ontario, Canada
| | - Alan C Peterson
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
- Gerald Bronfman Department of Oncology, McGill University, Quebec, Canada
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2
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Miyazaki H, Nishioka S, Yamanaka T, Abe M, Imamura Y, Miyasaka T, Kakuda N, Oohashi T, Shimogori T, Yamakawa K, Ikawa M, Nukina N. Generation and characterization of cerebellar granule neurons specific knockout mice of Golli-MBP. Transgenic Res 2024; 33:99-117. [PMID: 38684589 PMCID: PMC11176102 DOI: 10.1007/s11248-024-00382-0] [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: 11/30/2023] [Accepted: 04/02/2024] [Indexed: 05/02/2024]
Abstract
Golli-myelin basic proteins, encoded by the myelin basic protein gene, are widely expressed in neurons and oligodendrocytes in the central nervous system. Further, prior research has shown that Golli-myelin basic protein is necessary for myelination and neuronal maturation during central nervous system development. In this study, we established Golli-myelin basic protein-floxed mice to elucidate the cell-type-specific effects of Golli-myelin basic protein knockout through the generation of conditional knockout mice (Golli-myelin basic proteinsfl/fl; E3CreN), in which Golli-myelin basic proteins were specifically deleted in cerebellar granule neurons, where Golli-myelin basic proteins are expressed abundantly in wild-type mice. To investigate the role of Golli-myelin basic proteins in cerebellar granule neurons, we further performed histopathological analyses of these mice, with results indicating no morphological changes or degeneration of the major cellular components of the cerebellum. Furthermore, behavioral analysis showed that Golli-myelin basic proteinsfl/fl; E3CreN mice were healthy and did not display any abnormal behavior. These results suggest that the loss of Golli-myelin basic proteins in cerebellar granule neurons does not lead to cerebellar perturbations or behavioral abnormalities. This mouse model could therefore be employed to analyze the effect of Golli-myelin basic protein deletion in specific cell types of the central nervous system, such as other neuronal cells and oligodendrocytes, or in lymphocytes of the immune system.
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Grants
- 16K07005 Grants-in-Aid from the Ministry of Education, Culture, Sports, Science, and Technology (MEXT) of Japan
- 16H06276 Grants-in-Aid from the Ministry of Education, Culture, Sports, Science, and Technology (MEXT) of Japan
- 17H01564 Grants-in-Aid from the Ministry of Education, Culture, Sports, Science, and Technology (MEXT) of Japan
- 20ek0109310h0003 AMED
- The Center for Baby Science, Doshisha University
- Takeda Science Foundation
- Ichiro Kanehara Foundation for the Promotion of Medical Sciences and Medical Care
- Okayama University
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Affiliation(s)
- Haruko Miyazaki
- Laboratory of Structural Neuropathology, Graduate School of Brain Science, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe-shi, Kyoto, 610-0394, Japan.
- Department of Molecular Biology and Biochemistry, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan.
| | - Saki Nishioka
- Department of Experimental Genome Research, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Tomoyuki Yamanaka
- Laboratory of Structural Neuropathology, Graduate School of Brain Science, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe-shi, Kyoto, 610-0394, Japan
- Department of Neuroscience of Disease, Brain Research Institute, Niigata University, 1-757 Asahimachidori, Chuo-ku, Niigata, 951-8585, Japan
| | - Manabu Abe
- Department of Animal Model Development, Brain Research Institute, Niigata University, 1-757 Asahimachidori, Chuo-ku, Niigata, 951-8585, Japan
| | - Yukio Imamura
- Laboratory of Structural Neuropathology, Graduate School of Brain Science, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe-shi, Kyoto, 610-0394, Japan
| | - Tomohiro Miyasaka
- Faculty of Life and Medical Sciences, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe-shi, Kyoto, 610-0394, Japan
| | - Nobuto Kakuda
- Faculty of Life and Medical Sciences, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe-shi, Kyoto, 610-0394, Japan
| | - Toshitaka Oohashi
- Department of Molecular Biology and Biochemistry, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan
| | - Tomomi Shimogori
- Laboratory for Molecular Mechanisms of Brain Development, RIKEN Center for Brain Science, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198, Japan
| | - Kazuhiro Yamakawa
- Laboratory for Neurogenetics, RIKEN Center for Brain Science, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198, Japan
- Department of Neurodevelopmental Disorder Genetics, Institute of Brain Sciences, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, 467-8601, Japan
| | - Masahito Ikawa
- Department of Experimental Genome Research, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Nobuyuki Nukina
- Laboratory of Structural Neuropathology, Graduate School of Brain Science, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe-shi, Kyoto, 610-0394, Japan.
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3
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Ghosh T, Almeida RG, Zhao C, Mannioui A, Martin E, Fleet A, Chen CZ, Assinck P, Ellams S, Gonzalez GA, Graham SC, Rowitch DH, Stott K, Adams I, Zalc B, Goldman N, Lyons DA, Franklin RJM. A retroviral link to vertebrate myelination through retrotransposon-RNA-mediated control of myelin gene expression. Cell 2024; 187:814-830.e23. [PMID: 38364788 DOI: 10.1016/j.cell.2024.01.011] [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: 12/12/2022] [Revised: 10/12/2023] [Accepted: 01/07/2024] [Indexed: 02/18/2024]
Abstract
Myelin, the insulating sheath that surrounds neuronal axons, is produced by oligodendrocytes in the central nervous system (CNS). This evolutionary innovation, which first appears in jawed vertebrates, enabled rapid transmission of nerve impulses, more complex brains, and greater morphological diversity. Here, we report that RNA-level expression of RNLTR12-int, a retrotransposon of retroviral origin, is essential for myelination. We show that RNLTR12-int-encoded RNA binds to the transcription factor SOX10 to regulate transcription of myelin basic protein (Mbp, the major constituent of myelin) in rodents. RNLTR12-int-like sequences (which we name RetroMyelin) are found in all jawed vertebrates, and we further demonstrate their function in regulating myelination in two different vertebrate classes (zebrafish and frogs). Our study therefore suggests that retroviral endogenization played a prominent role in the emergence of vertebrate myelin.
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Affiliation(s)
- Tanay Ghosh
- Altos Labs-Cambridge Institute of Science, Cambridge CB21 6GP, UK; Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge CB2 0AW, UK; Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AW, UK.
| | - Rafael G Almeida
- Centre for Discovery Brain Sciences, MS society Edinburgh Centre for MS Research, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Chao Zhao
- Altos Labs-Cambridge Institute of Science, Cambridge CB21 6GP, UK; Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge CB2 0AW, UK; Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AW, UK
| | - Abdelkrim Mannioui
- Sorbonne Université, Institut de Biologie Paris-Seine (IBPS), Aquatic Facility, 75005 Paris, France
| | - Elodie Martin
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, 75013 Paris, France
| | - Alex Fleet
- Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge CB2 0AW, UK; Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AW, UK
| | - Civia Z Chen
- Altos Labs-Cambridge Institute of Science, Cambridge CB21 6GP, UK; Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge CB2 0AW, UK; Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AW, UK
| | - Peggy Assinck
- Altos Labs-Cambridge Institute of Science, Cambridge CB21 6GP, UK; Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge CB2 0AW, UK; Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AW, UK
| | - Sophie Ellams
- Altos Labs-Cambridge Institute of Science, Cambridge CB21 6GP, UK
| | - Ginez A Gonzalez
- Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge CB2 0AW, UK; Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AW, UK
| | - Stephen C Graham
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - David H Rowitch
- Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge CB2 0AW, UK; Department of Paediatrics, University of Cambridge, Cambridge, UK
| | - Katherine Stott
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
| | - Ian Adams
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Bernard Zalc
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, 75013 Paris, France
| | - Nick Goldman
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome, Genome Campus, Hinxton, Cambridge CB10 1SD, UK
| | - David A Lyons
- Centre for Discovery Brain Sciences, MS society Edinburgh Centre for MS Research, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Robin J M Franklin
- Altos Labs-Cambridge Institute of Science, Cambridge CB21 6GP, UK; Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge CB2 0AW, UK; Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AW, UK.
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4
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Abstract
Myelination of axons provides the structural basis for rapid saltatory impulse propagation along vertebrate fiber tracts, a well-established neurophysiological concept. However, myelinating oligodendrocytes and Schwann cells serve additional functions in neuronal energy metabolism that are remarkably similar to those of axon-ensheathing glial cells in unmyelinated invertebrates. Here we discuss myelin evolution and physiological glial functions, beginning with the role of ensheathing glia in preventing ephaptic coupling, axoglial metabolic support, and eliminating oxidative radicals. In both vertebrates and invertebrates, axoglial interactions are bidirectional, serving to regulate cell fate, nerve conduction, and behavioral performance. One key step in the evolution of compact myelin in the vertebrate lineage was the emergence of the open reading frame for myelin basic protein within another gene. Several other proteins were neofunctionalized as myelin constituents and help maintain a healthy nervous system. Myelination in vertebrates became a major prerequisite of inhabiting new ecological niches.
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Affiliation(s)
- Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, D-37075 Göttingen, Germany; ,
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, D-37075 Göttingen, Germany; ,
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5
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Yuan Z, Chen P, Zhang T, Shen B, Chen L. Agenesis and Hypomyelination of Corpus Callosum in Mice Lacking Nsun5, an RNA Methyltransferase. Cells 2019; 8:cells8060552. [PMID: 31174389 PMCID: PMC6627898 DOI: 10.3390/cells8060552] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 06/03/2019] [Accepted: 06/04/2019] [Indexed: 11/16/2022] Open
Abstract
Williams-Beuren syndrome (WBS) is caused by microdeletions of 28 genes and is characterized by cognitive disorder and hypotrophic corpus callosum (CC). Nsun5 gene, which encodes cytosine-5 RNA methyltransferase, is located in the deletion loci of WBS. We have reported that single-gene knockout of Nsun5 (Nsun5-KO) in mice impairs spatial cognition. Herein, we report that postnatal day (PND) 60 Nsun5-KO mice showed the volumetric reduction of CC with a decline in the number of myelinated axons and loose myelin sheath. Nsun5 was highly expressed in callosal oligodendrocyte precursor cells (OPCs) and oligodendrocytes (OLs) from PND7 to PND28. The numbers of OPCs and OLs in CC of PND7-28 Nsun5-KO mice were significantly reduced compared to wild-type littermates. Immunohistochemistry and Western blot analyses of myelin basic protein (MBP) showed the hypomyelination in the CC of PND28 Nsun5-KO mice. The Nsun5 deletion suppressed the proliferation of OPCs but did not affect transition of radial glial cells into OPCs or cell cycle exit of OPCs. The protein levels, rather than transcriptional levels, of CDK1, CDK2 and Cdc42 in the CC of PND7 and PND14 Nsun5-KO mice were reduced. These findings point to the involvement of Nsun5 deletion in agenesis of CC observed in WBS.
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Affiliation(s)
- Zihao Yuan
- State Key Laboratory of Reproductive Medicine, Department of Physiology, Nanjing Medical University, Nanjing 211166, China.
- Department of Physiology, Nanjing Medical University, Nanjing 211166, China.
| | - Peipei Chen
- State Key Laboratory of Reproductive Medicine, Department of Physiology, Nanjing Medical University, Nanjing 211166, China.
- Department of Physiology, Nanjing Medical University, Nanjing 211166, China.
| | - Tingting Zhang
- State Key Laboratory of Reproductive Medicine, Department of Physiology, Nanjing Medical University, Nanjing 211166, China.
- Department of Physiology, Nanjing Medical University, Nanjing 211166, China.
| | - Bin Shen
- State Key Laboratory of Reproductive Medicine, Department of Physiology, Nanjing Medical University, Nanjing 211166, China.
| | - Ling Chen
- State Key Laboratory of Reproductive Medicine, Department of Physiology, Nanjing Medical University, Nanjing 211166, China.
- Department of Physiology, Nanjing Medical University, Nanjing 211166, China.
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6
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Conditional Deletion of the L-Type Calcium Channel Cav1.2 in Oligodendrocyte Progenitor Cells Affects Postnatal Myelination in Mice. J Neurosci 2017; 36:10853-10869. [PMID: 27798140 DOI: 10.1523/jneurosci.1770-16.2016] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 09/03/2016] [Indexed: 12/12/2022] Open
Abstract
To determine whether L-type voltage-operated Ca2+ channels (L-VOCCs) are required for oligodendrocyte progenitor cell (OPC) development, we generated an inducible conditional knock-out mouse in which the L-VOCC isoform Cav1.2 was postnatally deleted in NG2-positive OPCs. A significant hypomyelination was found in the brains of the Cav1.2 conditional knock-out (Cav1.2KO) mice specifically when the Cav1.2 deletion was induced in OPCs during the first 2 postnatal weeks. A decrease in myelin proteins expression was visible in several brain structures, including the corpus callosum, cortex, and striatum, and the corpus callosum of Cav1.2KO animals showed an important decrease in the percentage of myelinated axons and a substantial increase in the mean g-ratio of myelinated axons. The reduced myelination was accompanied by an important decline in the number of myelinating oligodendrocytes and in the rate of OPC proliferation. Furthermore, using a triple transgenic mouse in which all of the Cav1.2KO OPCs were tracked by a Cre reporter, we found that Cav1.2KO OPCs produce less mature oligodendrocytes than control cells. Finally, live-cell imaging in early postnatal brain slices revealed that the migration and proliferation of subventricular zone OPCs is decreased in the Cav1.2KO mice. These results indicate that the L-VOCC isoform Cav1.2 modulates oligodendrocyte development and suggest that Ca2+ influx mediated by L-VOCCs in OPCs is necessary for normal myelination. SIGNIFICANCE STATEMENT Overall, it is clear that cells in the oligodendrocyte lineage exhibit remarkable plasticity with regard to the expression of Ca2+ channels and that perturbation of Ca2+ homeostasis likely plays an important role in the pathogenesis underlying demyelinating diseases. To determine whether voltage-gated Ca2+ entry is involved in oligodendrocyte maturation and myelination, we used a conditional knock-out mouse for voltage-operated Ca2+ channels in oligodendrocyte progenitor cells. Our results indicate that voltage-operated Ca2+ channels can modulate oligodendrocyte development in the postnatal brain and suggest that voltage-gated Ca2+ influx in oligodendroglial cells is critical for normal myelination. These findings could lead to novel approaches to intervene in neurodegenerative diseases in which myelin is lost or damaged.
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7
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Gene expression alterations related to mania and psychosis in peripheral blood of patients with a first episode of psychosis. Transl Psychiatry 2016; 6:e908. [PMID: 27701407 PMCID: PMC5315542 DOI: 10.1038/tp.2016.159] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 06/23/2016] [Accepted: 07/12/2016] [Indexed: 01/11/2023] Open
Abstract
Psychotic disorders affect ~3% of the general population and are among the most severe forms of mental diseases. In early stages of psychosis, clinical aspects may be difficult to distinguish from one another. Undifferentiated psychopathology at the first-episode of psychosis (FEP) highlights the need for biomarkers that can improve and refine differential diagnosis. We investigated gene expression differences between patients with FEP-schizophrenia spectrum (SCZ; N=53) or FEP-Mania (BD; N=16) and healthy controls (N=73). We also verified whether gene expression was correlated to severity of psychotic, manic, depressive symptoms and/or functional impairment. All participants were antipsychotic-naive. After the psychiatric interview, blood samples were collected and the expression of 12 psychotic-disorder-related genes was evaluated by quantitative PCR. AKT1 and DICER1 expression levels were higher in BD patients compared with that in SCZ patients and healthy controls, suggesting that expression of these genes is associated more specifically to manic features. Furthermore, MBP and NDEL1 expression levels were higher in SCZ and BD patients than in healthy controls, indicating that these genes are psychosis related (independent of diagnosis). No correlation was found between gene expression and severity of symptoms or functional impairment. Our findings suggest that genes related to neurodevelopment are altered in psychotic disorders, and some might support the differential diagnosis between schizophrenia and bipolar disorder, with a potential impact on the treatment of these disorders.
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8
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Ouyang S, Han G, Wu X, Jiang Z, Feng JM. Accelerated progression of Hodgkin's-like lymphomas in golli deficient SJL mice. Cell Immunol 2016; 302:41-49. [PMID: 26877250 DOI: 10.1016/j.cellimm.2016.01.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 01/25/2016] [Accepted: 01/28/2016] [Indexed: 11/16/2022]
Abstract
Spontaneously occurring lymphomas in SJL mice have many pathological features similar to Hodgkin's lymphoma in humans. The malignant growth of the tumor cells is dependent on the support of host FoxP3(+)CD4(+) regulatory T cells (Tregs). In this study, we report that the ablation of golli protein, a negative regulator of CRAC (calcium release activated calcium) channel, in SJL mice results in an accelerated progression of Hodgkin's-like lymphoma which is accompanied by a facilitated conversion of FoxP3(+) Treg cells. Our results suggest that golli protein might affect the progression of Hodgkin's-like lymphomas through regulating the induction of Treg cells.
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Affiliation(s)
- Suidong Ouyang
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Guangming Han
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Xiaochu Wu
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Zhengfan Jiang
- The Education Ministry Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China
| | - Ji-Ming Feng
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA.
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9
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Ota VK, Noto C, Santoro ML, Spindola LM, Gouvea ES, Carvalho CM, Santos CM, Xavier G, Higuchi CH, Yonamine C, Moretti PN, Abílio VC, Hayashi MAF, Brietzke E, Gadelha A, Cordeiro Q, Bressan RA, Belangero SI. Increased expression of NDEL1 and MBP genes in the peripheral blood of antipsychotic-naïve patients with first-episode psychosis. Eur Neuropsychopharmacol 2015; 25:2416-25. [PMID: 26476704 DOI: 10.1016/j.euroneuro.2015.09.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 08/12/2015] [Accepted: 09/24/2015] [Indexed: 01/22/2023]
Abstract
Schizophrenia is a multifactorial neurodevelopmental disorder with high heritability. First-episode psychosis (FEP) is a critical period for determining the disease prognosis and is especially helpful for identifying potential biomarkers associated with the onset and progression of the disorder. We investigated the mRNA expression of 12 schizophrenia-related genes in the blood of antipsychotic-naïve FEP patients (N=73) and healthy controls (N=73). To evaluate the influences of antipsychotic treatment and progression of the disorder, we compared the gene expression within patients before and after two months of treatment with risperidone (N=64). We observed a significantly increased myelin basic protein (MBP) and nuclear distribution protein nudE-like 1 (NDEL1) mRNA levels in FEP patients compared with controls. Comparing FEP before and after risperidone treatment, no significant differences were identified; however; a trend of relatively low NDEL1 expression was observed after risperidone treatment. Animals chronically treated with saline or risperidone exhibited no significant change in Ndel1 expression levels in the blood or the prefrontal cortex (PFC), suggesting that the trend of low NDEL1 expression observed in FEP patients after treatment is likely due to factors other than risperidone treatment (i.e., disease progression). In addition to the recognized association with schizophrenia, MBP and NDEL1 gene products also play an essential role in the functions that are deregulated in schizophrenia, such as neurodevelopment. Our data strengthen the importance of these biological processes in psychotic disorders, indicating that these changes can be detected peripherally and potentially represent putative novel blood biomarkers of susceptibility and disorder progression.
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Affiliation(s)
- Vanessa Kiyomi Ota
- Genetics Division of Department of Morphology and Genetics of Universidade Federal de Sao Paulo (UNIFESP), Brazil; LiNC - Interdisciplinary Laboratory of Clinical Neurosciences of UNIFESP, Brazil; Department of Psychiatry of UNIFESP, Brazil
| | - Cristiano Noto
- LiNC - Interdisciplinary Laboratory of Clinical Neurosciences of UNIFESP, Brazil; Department of Psychiatry of UNIFESP, Brazil; Department of Psychiatry of Irmandade da Santa Casa de Misericórdia de São Paulo (ISCMSP), Brazil
| | - Marcos Leite Santoro
- Genetics Division of Department of Morphology and Genetics of Universidade Federal de Sao Paulo (UNIFESP), Brazil; LiNC - Interdisciplinary Laboratory of Clinical Neurosciences of UNIFESP, Brazil
| | - Leticia Maria Spindola
- Genetics Division of Department of Morphology and Genetics of Universidade Federal de Sao Paulo (UNIFESP), Brazil; LiNC - Interdisciplinary Laboratory of Clinical Neurosciences of UNIFESP, Brazil; Department of Psychiatry of UNIFESP, Brazil
| | - Eduardo Sauerbronn Gouvea
- Department of Psychiatry of UNIFESP, Brazil; Department of Psychiatry of Irmandade da Santa Casa de Misericórdia de São Paulo (ISCMSP), Brazil
| | - Carolina Muniz Carvalho
- Genetics Division of Department of Morphology and Genetics of Universidade Federal de Sao Paulo (UNIFESP), Brazil; LiNC - Interdisciplinary Laboratory of Clinical Neurosciences of UNIFESP, Brazil
| | - Camila Maurício Santos
- LiNC - Interdisciplinary Laboratory of Clinical Neurosciences of UNIFESP, Brazil; Department of Psychiatry of UNIFESP, Brazil
| | - Gabriela Xavier
- Genetics Division of Department of Morphology and Genetics of Universidade Federal de Sao Paulo (UNIFESP), Brazil; LiNC - Interdisciplinary Laboratory of Clinical Neurosciences of UNIFESP, Brazil
| | - Cinthia Hiroko Higuchi
- LiNC - Interdisciplinary Laboratory of Clinical Neurosciences of UNIFESP, Brazil; Department of Psychiatry of UNIFESP, Brazil
| | - Camila Yonamine
- LiNC - Interdisciplinary Laboratory of Clinical Neurosciences of UNIFESP, Brazil; Department of Pharmacology of UNIFESP, Brazil
| | - Patricia Natalia Moretti
- Genetics Division of Department of Morphology and Genetics of Universidade Federal de Sao Paulo (UNIFESP), Brazil; LiNC - Interdisciplinary Laboratory of Clinical Neurosciences of UNIFESP, Brazil; Department of Psychiatry of UNIFESP, Brazil
| | - Vanessa Costhek Abílio
- LiNC - Interdisciplinary Laboratory of Clinical Neurosciences of UNIFESP, Brazil; Department of Psychiatry of UNIFESP, Brazil; Department of Pharmacology of UNIFESP, Brazil
| | - Mirian Akemi F Hayashi
- LiNC - Interdisciplinary Laboratory of Clinical Neurosciences of UNIFESP, Brazil; Department of Pharmacology of UNIFESP, Brazil
| | - Elisa Brietzke
- LiNC - Interdisciplinary Laboratory of Clinical Neurosciences of UNIFESP, Brazil; Department of Psychiatry of UNIFESP, Brazil
| | - Ary Gadelha
- LiNC - Interdisciplinary Laboratory of Clinical Neurosciences of UNIFESP, Brazil; Department of Psychiatry of UNIFESP, Brazil
| | - Quirino Cordeiro
- Department of Psychiatry of UNIFESP, Brazil; Department of Psychiatry of Irmandade da Santa Casa de Misericórdia de São Paulo (ISCMSP), Brazil
| | - Rodrigo Affonseca Bressan
- LiNC - Interdisciplinary Laboratory of Clinical Neurosciences of UNIFESP, Brazil; Department of Psychiatry of UNIFESP, Brazil
| | - Sintia Iole Belangero
- Genetics Division of Department of Morphology and Genetics of Universidade Federal de Sao Paulo (UNIFESP), Brazil; LiNC - Interdisciplinary Laboratory of Clinical Neurosciences of UNIFESP, Brazil; Department of Psychiatry of UNIFESP, Brazil.
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Cheli VT, Santiago González DA, Spreuer V, Handley V, Campagnoni AT, Paez PM. Golli Myelin Basic Proteins Modulate Voltage-Operated Ca(++) Influx and Development in Cortical and Hippocampal Neurons. Mol Neurobiol 2015; 53:5749-71. [PMID: 26497031 DOI: 10.1007/s12035-015-9499-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 10/19/2015] [Indexed: 12/14/2022]
Abstract
The golli proteins, products of the myelin basic protein gene, are widely expressed in oligodendrocyte progenitor cells and neurons during the postnatal development of the brain. While golli appears to be important for oligodendrocyte migration and differentiation, its function in neuronal development is completely unknown. We have found that golli proteins function as new and novel modulators of voltage-operated Ca(++) channels (VOCCs) in neurons. In vitro, golli knock-out (KO) neurons exhibit decreased Ca(++) influx after plasma membrane depolarization and a substantial maturational delay. Increased expression of golli proteins enhances L-type Ca(++) entry and processes outgrowth in cortical neurons, and pharmacological activation of L-type Ca(++) channels stimulates maturation and prevents cell death in golli-KO neurons. In situ, Ca(++) influx mediated by L-type VOCCs was significantly decreased in cortical and hippocampal neurons of the golli-KO brain. These Ca(++) alterations affect cortical and hippocampal development and the proliferation and survival of neural progenitor cells during the postnatal development of the golli-KO brain. The CA1/3 sections and the dentate gyrus of the hippocampus were reduced in the golli-KO mice as well as the density of dendrites in the somatosensory cortex. Furthermore, the golli-KO mice display abnormal behavior including deficits in episodic memory and reduced anxiety. Because of the expression of the golli proteins within neurons in learning and memory centers of the brain, this work has profound implication in neurodegenerative diseases and neurological disorders.
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Affiliation(s)
- V T Cheli
- Hunter James Kelly Research Institute, Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, SUNY, University at Buffalo, NYS Center of Excellence, 701 Ellicott St., Buffalo, NY, 14203, USA
| | - D A Santiago González
- Hunter James Kelly Research Institute, Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, SUNY, University at Buffalo, NYS Center of Excellence, 701 Ellicott St., Buffalo, NY, 14203, USA
| | - V Spreuer
- Hunter James Kelly Research Institute, Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, SUNY, University at Buffalo, NYS Center of Excellence, 701 Ellicott St., Buffalo, NY, 14203, USA
| | - V Handley
- Semel Institute for Neuroscience and Human Behavior, Intellectual and Developmental Disabilities Research Center, David Geffen School of Medicine, UCLA, Neuroscience Research Building, 635 Charles Young Drive, Los Angeles, CA, 90095, USA
| | - A T Campagnoni
- Semel Institute for Neuroscience and Human Behavior, Intellectual and Developmental Disabilities Research Center, David Geffen School of Medicine, UCLA, Neuroscience Research Building, 635 Charles Young Drive, Los Angeles, CA, 90095, USA
| | - P M Paez
- Hunter James Kelly Research Institute, Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, SUNY, University at Buffalo, NYS Center of Excellence, 701 Ellicott St., Buffalo, NY, 14203, USA.
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11
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Siu CR, Balsor JL, Jones DG, Murphy KM. Classic and Golli Myelin Basic Protein have distinct developmental trajectories in human visual cortex. Front Neurosci 2015; 9:138. [PMID: 25964736 PMCID: PMC4408849 DOI: 10.3389/fnins.2015.00138] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 04/02/2015] [Indexed: 01/03/2023] Open
Abstract
Traditionally, myelin is viewed as insulation around axons, however, more recent studies have shown it also plays an important role in plasticity, axonal metabolism, and neuroimmune signaling. Myelin is a complex multi-protein structure composed of hundreds of proteins, with Myelin Basic Protein (MBP) being the most studied. MBP has two families: Classic-MBP that is necessary for activity driven compaction of myelin around axons, and Golli-MBP that is found in neurons, oligodendrocytes, and T-cells. Furthermore, Golli-MBP has been called a “molecular link” between the nervous and immune systems. In visual cortex specifically, myelin proteins interact with immune processes to affect experience-dependent plasticity. We studied myelin in human visual cortex using Western blotting to quantify Classic- and Golli-MBP expression in post-mortem tissue samples ranging in age from 20 days to 80 years. We found that Classic- and Golli-MBP have different patterns of change across the lifespan. Classic-MBP gradually increases to 42 years and then declines into aging. Golli-MBP has early developmental changes that are coincident with milestones in visual system sensitive period, and gradually increases into aging. There are three stages in the balance between Classic- and Golli-MBP expression, with Golli-MBP dominating early, then shifting to Classic-MBP, and back to Golli-MBP in aging. Also Golli-MBP has a wave of high inter-individual variability during childhood. These results about cortical MBP expression are timely because they compliment recent advances in MRI techniques that produce high resolution maps of cortical myelin in normal and diseased brain. In addition, the unique pattern of Golli-MBP expression across the lifespan suggests that it supports high levels of neuroimmune interaction in cortical development and in aging.
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Affiliation(s)
- Caitlin R Siu
- McMaster Integrative Neuroscience Discovery and Study Program, McMaster University Hamilton, ON, Canada
| | - Justin L Balsor
- McMaster Integrative Neuroscience Discovery and Study Program, McMaster University Hamilton, ON, Canada
| | | | - Kathryn M Murphy
- McMaster Integrative Neuroscience Discovery and Study Program, McMaster University Hamilton, ON, Canada ; Psychology, Neuroscience and Behaviour, McMaster University Hamilton, ON, Canada
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12
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Nallar SC, Kalvakolanu DV. Interferons, signal transduction pathways, and the central nervous system. J Interferon Cytokine Res 2015; 34:559-76. [PMID: 25084173 DOI: 10.1089/jir.2014.0021] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The interferon (IFN) family of cytokines participates in the development of innate and acquired immune defenses against various pathogens and pathogenic stimuli. Discovered originally as a proteinaceous substance secreted from virus-infected cells that afforded immunity to neighboring cells from virus infection, these cytokines are now implicated in various human pathologies, including control of tumor development, cell differentiation, and autoimmunity. It is now believed that the IFN system (IFN genes and the genes induced by them, and the factors that regulate these processes) is a generalized alarm of cellular stress, including DNA damage. IFNs exert both beneficial and deleterious effects on the central nervous system (CNS). Our knowledge of the IFN-regulated processes in the CNS is far from being clear. In this article, we reviewed the current understanding of IFN signal transduction pathways and gene products that might have potential relevance to diseases of the CNS.
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Affiliation(s)
- Shreeram C Nallar
- Department of Microbiology & Immunology, Program in Oncology, Greenebaum Cancer Center, University of Maryland School of Medicine , Baltimore, Maryland
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13
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Transcriptional upregulation of myelin components in spontaneous myelin basic protein-deficient mice. Brain Res 2015; 1606:125-32. [PMID: 25708149 DOI: 10.1016/j.brainres.2015.02.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/10/2015] [Accepted: 02/12/2015] [Indexed: 11/21/2022]
Abstract
Myelin is essential for efficient signal transduction in the nervous system comprising of multiple proteins. The intricacies of the regulation of the formation of myelin, and its components, are not fully understood. Here, we describe the characterization of a novel myelin basic protein (Mbp) mutant mouse, mbp(jive), which spontaneously occurred in our mouse colony. These mice displayed the onset of a shaking gait before 3 weeks of age and seizure onset before 2 months of age. Due to a progressive increase of seizure intensity, mbp(jive) mice experienced premature lethality at around 3 months of age. Mbp mRNA transcript or protein was undetectable and, accordingly, genetic analysis demonstrated a homozygous loss of exons 3 to 6 of Mbp. Peripheral nerve conductance was mostly unimpaired. Additionally, we observed grave structural changes in white matter predominant structures were detected by T1, T2 and diffusion weighted magnetic resonance imaging. We additionally observed that Mbp-deficiency results in an upregulation of Qkl, Mag and Cnp, suggestive of a regulatory feedback mechanism whereby compensatory increases in Qkl have downstream effects on Mag and Cnp. Further research will clarify the role and specifications of this myelin feedback loop, as well as determine its potential role in therapeutic strategies for demyelinating disorders.
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14
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Jaramillo-Tatis S, Bamm VV, Vassall KA, Harauz G. Over-expression in E. coli and purification of functional full-length murine small C-terminal domain phosphatase (SCP1, or Golli-interacting protein). Protein Expr Purif 2014; 101:106-14. [PMID: 24925644 DOI: 10.1016/j.pep.2014.05.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 05/26/2014] [Accepted: 05/31/2014] [Indexed: 01/13/2023]
Abstract
During myelination in the central nervous system, proteins arising from the gene in the oligodendrocyte lineage (golli) participate in diverse events in signal transduction and gene regulation. One of the interacting partners of the Golli-isoform BG21 was discovered by yeast-2-hybrid means and was denoted the Golli-interacting-protein (GIP). In subsequent in vitro studies of recombinant murine GIP, it was not possible to produce a full-length version of recombinant murine rmGIP in functional form under native conditions, primarily because of solubility issues, necessitating the study of a hexahistidine-tagged, truncated form ΔN-rmGIP. This protein is an acidic phosphatase belonging to the family of RNA-polymerase-2, small-subunit, C-terminal phosphatases (SCP1), and studies of the human ortholog hSCP1 have also been performed on truncated forms. Here, a new SUMO-expression and purification protocol has been developed for the preparation of a functional, full-length mSCP1/GIP (our nomenclature henceforth), with no additional purification tags. Both full-length mSCP1/GIP and the truncated murine form (now denoted ΔN-rmSCP1/GIP) had similar melting temperatures, indicating that the integrity of the catalytic core per se was minimally affected by the N-terminus. Characterization of mSCP1/GIP activity with the artificial substrate p-NPP (p-nitrophenylphosphate) yielded kinetic parameters comparable to those of ΔN-rmSCP1/GIP and the truncated human ortholog ΔN-hSCP1. Similarly, mSCP1/GIP dephosphorylated a more natural CTD-peptide substrate (but not protein kinase C-phosphorylated BG21) with comparable kinetics to ΔN-hSCP1. The successful production of an active, full-length mSCP1/GIP will enable future evaluation of the functional role of its N-terminus in protein-protein interactions (e.g., BG21) that regulate its phosphatase activity.
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Affiliation(s)
- Sergio Jaramillo-Tatis
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada
| | - Vladimir V Bamm
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada
| | - Kenrick A Vassall
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada
| | - George Harauz
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada.
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15
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Werner HB. Do we have to reconsider the evolutionary emergence of myelin? Front Cell Neurosci 2013; 7:217. [PMID: 24298238 PMCID: PMC3828561 DOI: 10.3389/fncel.2013.00217] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 10/29/2013] [Indexed: 02/02/2023] Open
Affiliation(s)
- Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine Göttingen, Germany
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16
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Nawaz S, Schweitzer J, Jahn O, Werner HB. Molecular evolution of myelin basic protein, an abundant structural myelin component. Glia 2013; 61:1364-77. [DOI: 10.1002/glia.22520] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Schanila Nawaz
- Max Planck Institute of Experimental Medicine; Göttingen; Germany
| | - Jörn Schweitzer
- Developmental Biology; Institute of Biology 1; University of Freiburg; Germany
| | - Olaf Jahn
- Max Planck Institute of Experimental Medicine; Göttingen; Germany
| | - Hauke B. Werner
- Max Planck Institute of Experimental Medicine; Göttingen; Germany
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17
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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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18
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Padhi BK, Pelletier G. Perturbation of myelin basic protein (Mbp) splice variant expression in developing rat cerebellum following perinatal exposure to methylmercury. Toxicol Lett 2012; 213:374-80. [PMID: 22835759 DOI: 10.1016/j.toxlet.2012.07.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 07/12/2012] [Accepted: 07/14/2012] [Indexed: 01/01/2023]
Abstract
Myelin sheaths surrounding axons are essential for saltatory conduction of nerve impulse in the central nervous system. A major protein constituent of myelin sheaths is produced by the myelin basic protein (Mbp) gene, whose expression in oligodendrocytes is conserved across vertebrates. In rat, five Mbp splice variants resulting from alternative splicing of exons 2, 5 and/or 6 are characterized. We developed a PCR-based strategy to quantify individual Mbp splice variants and characterized a sixth Mbp splice variant lacking only exon 5. This newly identified splice variant is predominantly expressed in developing rat brain and has orthologs in mouse and human. Many neurotoxic chemicals can perturb myelination and Mbp gene expression. Regulation of Mbp gene expression at the post-transcriptional level was assessed following perinatal exposure to neurotoxic methylmercury (2 mg/kg b.w./day). Similar reductions in total and individual Mbp splice variant mRNA levels suggest that methylmercury-induced perturbation in Mbp gene expression occurred as a consequence of decreased oligodendrocyte cell population in absence of a significant impact on its post-transcriptional regulation.
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Affiliation(s)
- Bhaja K Padhi
- Hazard Identification Division, HECSB, Health Canada, Tunney's Pasture, Ottawa, ON, K1A 0L2, Canada
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19
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Paez PM, Cheli VT, Ghiani CA, Spreuer V, Handley VW, Campagnoni AT. Golli myelin basic proteins stimulate oligodendrocyte progenitor cell proliferation and differentiation in remyelinating adult mouse brain. Glia 2012; 60:1078-93. [PMID: 22447683 DOI: 10.1002/glia.22336] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Accepted: 03/09/2012] [Indexed: 02/06/2023]
Abstract
Golli myelin basic proteins are necessary for normal myelination, acting via voltage and store-dependent Ca(2+) entry at multiple steps during oligodendrocyte progenitor cell (OPC) development. To date nothing is known regarding the role of golli proteins in demyelination or remyelination events. Here the effects of golli ablation and overexpression in myelin loss and recovery were examined using the cuprizone (CPZ) model of demyelination/remyelination. We found severe demyelination in the corpus callosum (CC) of golli-overexpressing mice (JOE) during the CPZ treatment, which was accompanied by an increased number of reactive astrocytes and activation of microglia/macrophages. During demyelination of JOE brains, a significant increase in the number of proliferating OPCs was found in the CC as well as in the subventricular zone, and our data indicate that these progenitors matured and fully remyelinated the CC of JOE animals after CPZ withdrawal. In contrast, in the absence of golli (golli-KO mice) delayed myelin loss associated with a smaller immune response, and a lower number of OPCs was found in these mice during the CPZ treatment. Furthermore, incomplete remyelination was observed after CPZ removal in large areas of the CC of golli-KO mice, reflecting irregular recovery of the oligodendrocyte population and subsequent myelin sheath formation. Our findings demonstrate that golli proteins sensitize mature oligodendrocytes to CPZ-induced demyelination, while at the same time stimulate the proliferation/recruitment of OPCs during demyelination, resulting in accelerated remyelination.
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Affiliation(s)
- Pablo M Paez
- Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-7332, USA.
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20
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Abstract
Multiple sclerosis is believed to be mediated by T cells specific for myelin antigens that circulate harmlessly in the periphery of healthy individuals until they are erroneously activated by an environmental stimulus. Upon activation, the T cells enter the central nervous system and orchestrate an immune response against myelin. To understand the initial steps in the pathogenesis of multiple sclerosis, it is important to identify the mechanisms that maintain T-cell tolerance to myelin antigens and to understand how some myelin-specific T cells escape tolerance and what conditions lead to their activation. Central tolerance strongly shapes the peripheral repertoire of myelin-specific T cells, as most myelin-specific T cells are eliminated by clonal deletion in the thymus. Self-reactive T cells that escape central tolerance are generally capable only of low-avidity interactions with antigen-presenting cells. Despite the low avidity of these interactions, peripheral tolerance mechanisms are required to prevent spontaneous autoimmunity. Multiple peripheral tolerance mechanisms for myelin-specific T cells have been identified, the most important of which appears to be regulatory T cells. While most studies have focused on CD4(+) myelin-specific T cells, interesting differences in tolerance mechanisms and the conditions that abrogate these mechanisms have recently been described for CD8(+) myelin-specific T cells.
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Affiliation(s)
- Joan M Goverman
- Department of Immunology, University of Washington, Seattle, WA 98195, USA.
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21
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Fulton DL, Denarier E, Friedman HC, Wasserman WW, Peterson AC. Towards resolving the transcription factor network controlling myelin gene expression. Nucleic Acids Res 2011; 39:7974-91. [PMID: 21729871 PMCID: PMC3185407 DOI: 10.1093/nar/gkr326] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
In the central nervous system (CNS), myelin is produced from spirally-wrapped oligodendrocyte plasma membrane and, as exemplified by the debilitating effects of inherited or acquired myelin abnormalities in diseases such as multiple sclerosis, it plays a critical role in nervous system function. Myelin sheath production coincides with rapid up-regulation of numerous genes. The complexity of their subsequent expression patterns, along with recently recognized heterogeneity within the oligodendrocyte lineage, suggest that the regulatory networks controlling such genes drive multiple context-specific transcriptional programs. Conferring this nuanced level of control likely involves a large repertoire of interacting transcription factors (TFs). Here, we combined novel strategies of computational sequence analyses with in vivo functional analysis to establish a TF network model of coordinate myelin-associated gene transcription. Notably, the network model captures regulatory DNA elements and TFs known to regulate oligodendrocyte myelin gene transcription and/or oligodendrocyte development, thereby validating our approach. Further, it links to numerous TFs with previously unsuspected roles in CNS myelination and suggests collaborative relationships amongst both known and novel TFs, thus providing deeper insight into the myelin gene transcriptional network.
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Affiliation(s)
- Debra L Fulton
- Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, V5Z 4H4, Canada
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22
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Paez PM, Fulton D, Spreuer V, Handley V, Campagnoni AT. Modulation of canonical transient receptor potential channel 1 in the proliferation of oligodendrocyte precursor cells by the golli products of the myelin basic protein gene. J Neurosci 2011; 31:3625-37. [PMID: 21389218 PMCID: PMC3076512 DOI: 10.1523/jneurosci.4424-10.2011] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Revised: 11/22/2010] [Accepted: 01/03/2011] [Indexed: 12/18/2022] Open
Abstract
Golli proteins, products of the myelin basic protein gene, function as a new type of modulator of intracellular Ca(2+) levels in oligodendrocyte progenitor cells (OPCs). Because of this, they affect a number of Ca(2+)-dependent functions, such as OPC migration and process extension. To examine further the Ca(2+) channels regulated by golli, we studied the store-operated Ca(2+) channels (SOCCs) in OPCs and acute brain slice preparations from golli knock-out and golli-overexpressing mice. Our results showed that pharmacologically induced Ca(2+) release from intracellular stores evoked a significant extracellular Ca(2+) entry after store depletion in OPCs. They also indicated that, under these pharmacological conditions, golli promoted activation of Ca(2+) influx by SOCCs in cultured OPCs as well as in tissue slices. The canonical transient receptor potential family of Ca(2+) channels (TRPCs) has been postulated to be SOCC subunits in oligodendrocytes. Using a small interfering RNA knockdown approach, we provided direct evidence that TRPC1 is involved in store-operated Ca(2+) influx in OPCs and that it is modulated by golli. Furthermore, our data indicated that golli is probably associated with TRPC1 at OPC processes. Additionally, we found that TRPC1 expression is essential for the effects of golli on OPC proliferation. In summary, our data indicate a key role for golli proteins in the regulation of TRPC-mediated Ca(2+) influx, a finding that has profound consequences for the regulation of multiple biological processes in OPCs. More important, we have shown that extracellular Ca(2+) uptake through TRPC1 is an essential component in the mechanism of OPC proliferation.
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Affiliation(s)
- Pablo M Paez
- Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California at Los Angeles, California 90095-7332, USA.
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Fulton D, Paez PM, Fisher R, Handley V, Colwell CS, Campagnoni AT. Regulation of L-type Ca++ currents and process morphology in white matter oligodendrocyte precursor cells by golli-myelin proteins. Glia 2011; 58:1292-303. [PMID: 20607717 DOI: 10.1002/glia.21008] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The golli myelin basic proteins are expressed in oligodendroglial precursor cells (OPCs) where they play a role in regulating Ca(2+) homeostasis. During depolarization, they influence process outgrowth and migration through their action on voltage-operated Ca(2+) channels (VOCCs). To identify ion channels that are modulated by golli, we examined the electrophysiological properties of VOCCs in OPCs in the white matter of golli knock-out and control mice. OPCs exhibited two distinct Ca(2+) channels, which were distinguished by their voltage dependence and pharmacological profiles and which exhibited many of the hallmarks of LVA/T-type and HVA/L-type Ca(2+) channels. The density of high-voltage-activated (HVA) currents was reduced in OPCs recorded in golli-KO tissue, while low-voltage-activated (LVA) currents remained unaltered in these cells. These data indicate that golli exerts an exclusive influence on L-type Ca(2+) channels in OPCs. Oligodendrocytes (OLs) also displayed LVA and HVA currents, although the density of these currents was much reduced at this developmental stage. These currents were not altered in golli-KO OLs showing the influence of golli on L-type Ca(2+) channels is restricted to a specific time-window during the course of oligodendroglial development. The actions of golli on OPC L-type Ca(2+) channels were accompanied by changes in process morphology, including a reduction in process complexity and the appearance of enlarged varicosities that decorated these cellular processes. These data on L-type Ca(2+) channels and process development provide in situ evidence for the influence of golli on VOCCs, and offer an explanation for the hypomyelination observed in the brains of golli-KO mice.
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Affiliation(s)
- Daniel Fulton
- Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine at UCLA, University of California, Los Angeles, California, 90095, USA
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Nanba R, Fujita N, Nagata S. Structure and expression of myelin basic protein gene products in Xenopus laevis. Gene 2010; 459:32-8. [PMID: 20353813 DOI: 10.1016/j.gene.2010.03.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Revised: 03/13/2010] [Accepted: 03/18/2010] [Indexed: 01/06/2023]
Abstract
To study roles of the myelin basic protein (mbp) gene products in nervous system development, cDNA cloning and expression analyses were performed in Xenopus laevis. We cloned cDNAs for XMBP.1 and XMBP.2 encoded by xmbp.1 and xmbp.2 genes, respectively. We also identified xmbp.1 gene transcripts encoding three XGolli (X.laevis gene of the oligodendrocyte lineage) proteins, XBG21.1, XJ37.1, and XTP8.1, which are homologues of mouse BG21, J37, and TP8, respectively. In reverse transcription-polymerase chain reaction (RT-PCR) analyses, the XMBP, XJ37, and XTP8 mRNAs were expressed in brain, ovaries, testes, and/or thymus in frogs and in larvae after hatching. In contrast, the XBG21 mRNA was found fairly ubiquitously in adult tissues, unfertilized eggs and embryos throughout the developmental stages examined. Western blot analyses using three different monoclonal antibodies (mAbs) showed that the central and peripheral myelin contained 20kDa and18.5 kDa XMBP variants. In addition, XMBP was found in thymus by Western blotting and in thymocyte cytoplasm immunocytochemically. However, the XGolli protein, most provably XBG21, was detectable only in testes. The results indicate that the structure of xmbp gene products seems highly conserved among amphibians and mammals, although their expression patterns and thus physiological roles may partially differ. This is the first report that systematically describes the mbp gene products in nonmammalian vertebrates.
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Affiliation(s)
- Reiko Nanba
- Department of Chemical and Biological Sciences, Faculty of Science, Japan Women's University, Mejirodai 2-8-1, Bunkyoku, Tokyo 112-8681, Japan
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The multiple roles of myelin protein genes during the development of the oligodendrocyte. ASN Neuro 2010; 2:e00027. [PMID: 20017732 PMCID: PMC2814326 DOI: 10.1042/an20090051] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Revised: 12/14/2009] [Accepted: 12/17/2009] [Indexed: 11/22/2022] Open
Abstract
It has become clear that the products of several of the earliest identified myelin protein genes perform functions that extend beyond the myelin sheath. Interestingly, these myelin proteins, which comprise proteolipid protein, 2′,3′-cyclic nucleotide 3′-phosphodiesterase and the classic and golli MBPs (myelin basic proteins), play important roles during different stages of oligodendroglial development. These non-myelin-related functions are varied and include roles in the regulation of process outgrowth, migration, RNA transport, oligodendrocyte survival and ion channel modulation. However, despite the wide variety of cellular functions performed by the different myelin genes, the route by which they achieve these many functions seems to converge upon a common mechanism involving Ca2+ regulation, cytoskeletal rearrangements and signal transduction. In the present review, the newly emerging functions of these myelin proteins will be described, and these will then be discussed in the context of their contribution to oligodendroglial development.
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Shiryaev SA, Remacle AG, Savinov AY, Chernov AV, Cieplak P, Radichev IA, Williams R, Shiryaeva TN, Gawlik K, Postnova TI, Ratnikov BI, Eroshkin AM, Motamedchaboki K, Smith JW, Strongin AY. Inflammatory proprotein convertase-matrix metalloproteinase proteolytic pathway in antigen-presenting cells as a step to autoimmune multiple sclerosis. J Biol Chem 2009; 284:30615-26. [PMID: 19726693 PMCID: PMC2781616 DOI: 10.1074/jbc.m109.041244] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Revised: 08/25/2009] [Indexed: 11/06/2022] Open
Abstract
Multiple sclerosis (MS) is a disease of the central nervous system with autoimmune etiology. Susceptibility to MS is linked to viral and bacterial infections. Matrix metalloproteinases (MMPs) play a significant role in the fragmentation of myelin basic protein (MBP) and demyelination. The splice variants of the single MBP gene are expressed in the oligodendrocytes of the central nervous system (classic MBP) and in the immune cells (Golli-MBPs). Our data suggest that persistent inflammation caused by environmental risk factors is a step to MS. We have discovered biochemical evidence suggesting the presence of the inflammatory proteolytic pathway leading to MS. The pathway involves the self-activated furin and PC2 proprotein convertases and membrane type-6 MMP (MT6-MMP/MMP-25) that is activated by furin/PC2. These events are followed by MMP-25 proteolysis of the Golli-MBP isoforms in the immune system cells and stimulation of the specific autoimmune T cell clones. It is likely that the passage of these autoimmune T cell clones through the disrupted blood-brain barrier to the brain and the recognition of neuronal, classic MBP causes inflammation leading to the further up-regulation of the activity of the multiple individual MMPs, the massive cleavage of MBP in the brain, demyelination, and MS. In addition to the cleavage of Golli-MBPs, MMP-25 proteolysis readily inactivates crystallin alphaB that is a suppressor of MS. These data suggest that MMP-25 plays an important role in MS pathology and that MMP-25, especially because of its restricted cell/tissue expression pattern and cell surface/lipid raft localization, is a promising drug target in MS.
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Affiliation(s)
- Sergey A. Shiryaev
- From the Burnham Institute for Medical Research, La Jolla, California 92037
| | - Albert G. Remacle
- From the Burnham Institute for Medical Research, La Jolla, California 92037
| | - Alexei Y. Savinov
- From the Burnham Institute for Medical Research, La Jolla, California 92037
| | - Andrei V. Chernov
- From the Burnham Institute for Medical Research, La Jolla, California 92037
| | - Piotr Cieplak
- From the Burnham Institute for Medical Research, La Jolla, California 92037
| | - Ilian A. Radichev
- From the Burnham Institute for Medical Research, La Jolla, California 92037
| | - Roy Williams
- From the Burnham Institute for Medical Research, La Jolla, California 92037
| | | | - Katarzyna Gawlik
- From the Burnham Institute for Medical Research, La Jolla, California 92037
| | | | - Boris I. Ratnikov
- From the Burnham Institute for Medical Research, La Jolla, California 92037
| | - Alexei M. Eroshkin
- From the Burnham Institute for Medical Research, La Jolla, California 92037
| | | | - Jeffrey W. Smith
- From the Burnham Institute for Medical Research, La Jolla, California 92037
| | - Alex Y. Strongin
- From the Burnham Institute for Medical Research, La Jolla, California 92037
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Targeted overexpression of a golli-myelin basic protein isoform to oligodendrocytes results in aberrant oligodendrocyte maturation and myelination. ASN Neuro 2009; 1:AN20090029. [PMID: 19715557 PMCID: PMC2785512 DOI: 10.1042/an20090029] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Recently, several in vitro studies have shown that the golli–myelin basic proteins regulate Ca2+ homoeostasis in OPCs (oligodendrocyte precursor cells) and immature OLs (oligodendrocytes), and that a number of the functions of these cells are affected by cellular levels of the golli proteins. To determine the influence of golli in vivo on OL development and myelination, a transgenic mouse was generated in which the golli isoform J37 was overexpressed specifically within OLs and OPCs. The mouse, called JOE (J37-overexpressing), is severely hypomyelinated between birth and postnatal day 50. During this time, it exhibits severe intention tremors that gradually abate at later ages. After postnatal day 50, ultrastructural studies and Northern and Western blot analyses indicate that myelin accumulates in the brain, but never reaches normal levels. Several factors appear to underlie the extensive hypomyelination. In vitro and in vivo experiments indicate that golli overexpression causes a significant delay in OL maturation, with accumulation of significantly greater numbers of pre-myelinating OLs that fail to myelinate axons during the normal myelinating period. Immunohistochemical studies with cell death and myelin markers indicate that JOE OLs undergo a heightened and extended period of cell death and are unable to effectively myelinate until 2 months after birth. The results indicate that increased levels of golli in OPC/OLs delays myelination, causing significant cell death of OLs particularly in white matter tracts. The results provide in vivo evidence for a significant role of the golli proteins in the regulation of maturation of OLs and normal myelination.
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Association between golli-MBP and schizophrenia in the Jewish Ashkenazi population: are regulatory regions involved? Int J Neuropsychopharmacol 2009; 12:885-94. [PMID: 19154657 DOI: 10.1017/s1461145708009887] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Multiple studies have reported oligodendrocyte and myelin abnormalities, as well as dysregulation of their related genes, in brains of schizophrenia patients. One of these genes is the myelin-basic-protein (MBP) gene, which encodes two families of proteins: classic-MBPs and golli-MBPs. While the classic-MBPs are predominantly located in the myelin sheaths of the nervous system, the golli proteins are more widely expressed and are found in both the immune and the nervous systems. In the present study we performed a case-control association analysis of golli-MBP in two separate Jewish Ashkenazi cohorts (cohort I: 120 patients, 236 controls; cohort II: 379 patients, 380 controls). In addition we performed an expression analysis of golli-MBP mRNA in post-mortem dorsolateral prefrontal cortex samples of schizophrenia patients, and matched controls. In the first cohort we observed association between six (out of 26 genotyped) single nucleotide polymorphisms (SNPs) and the disease (p<0.05). Of these, three are from one linkage disequilibrium (LD) block which contains a CTCF binding region. Haplotype analysis revealed significant 'risk'/'protective' haplotypes (strongest p=0.005, each) for schizophrenia. The three SNPs (rs12458282, rs2008323, rs721286) were then genotyped in the second cohort. The combined results showed strong effects, both in the single marker and in haplotype analyses (strongest OR 1.77, p=0.0005; OR 1.61, p=0.00001, respectively). Sequencing the CTCF binding region revealed three SNPs in complete LD with the associated haplotypes, located in close proximity to the CTCF binding site. Expression analysis found no significant differences in golli-MBP mRNA levels. These findings suggest that golli-MBP is a possible susceptibility gene for schizophrenia.
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Golli myelin basic proteins regulate oligodendroglial progenitor cell migration through voltage-gated Ca2+ influx. J Neurosci 2009; 29:6663-76. [PMID: 19458236 DOI: 10.1523/jneurosci.5806-08.2009] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Migration of oligodendrocyte progenitor cells (OPCs) from proliferative zones to their final location in the brain is an essential step in nervous system development. Golli proteins, products of the myelin basic protein gene, can modulate voltage-gated Ca(2+) uptake in OPCs during process extension and retraction. Given the importance of process extension/retraction on movement, the consequences of golli expression on OPC migration were examined in vivo and in vitro using time-lapse imaging of isolated OPCs and acute brain slice preparations from golli KO and golli J37 overexpressing mice (JOE). The results indicated that golli stimulated migration, and this enhanced motility was associated with increases in the activity of voltage operated Ca(2+) channels (VOCCs). Activation of VOCCs by high K(+) resulted in a significant increase in the migration speed of JOE OPCs versus control cells and golli-mediated modulation of OPC migration disappeared in the presence of VOCC antagonists. During migration, OPCs generated Ca(2+) oscillations that were dependent on voltage-calcium influx and both the amplitude and frequency of these Ca(2+) transients correlated positively with the rate of cell movement under a variety of pharmacological treatments. The Ca(2+) transient amplitude and the rate of cell movement were significantly lower in KO cells and significantly higher in JOE cells suggesting that the presence of golli promotes OPC migration by increasing the size of voltage-mediated Ca(2+) oscillations. These data define a new molecule that regulates Ca(2+) homeostasis in OPCs, and are the first to demonstrate that voltage-gated Ca(2+) channels can regulate an OPC function, such as migration.
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Regulation of store-operated and voltage-operated Ca2+ channels in the proliferation and death of oligodendrocyte precursor cells by golli proteins. ASN Neuro 2009; 1:AN20090003. [PMID: 19570024 PMCID: PMC2695580 DOI: 10.1042/an20090003] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
OPCs (oligodendrocyte precursor cells) express golli proteins which, through regulation of Ca2+ influx, appear to be important in OPC process extension/retraction and migration. The aim of the present study was to examine further the role of golli in regulating OPC development. The effects of golli ablation and overexpression were examined in primary cultures of OPCs prepared from golli-KO (knockout) and JOE (golli J37-overexpressing) mice. In OPCs lacking golli, or overexpressing golli, differentiation induced by growth factor withdrawal was impaired. Proliferation analysis in the presence of PDGF (platelet-derived growth factor), revealed that golli enhanced the mitogen-stimulated proliferation of OPCs through activation of SOCCs (store-operated Ca2+ channels). PDGF treatment induced a biphasic increase in OPC intracellular Ca2+, and golli specifically increased Ca2+ influx during the second SOCC-dependent phase that followed the initial release of Ca2+ from intracellular stores. This store-operated Ca2+ uptake appeared to be essential for cell division, since specific SOCC antagonists completely blocked the effects of PDGF and golli on OPC proliferation. Additionally, in OPCs overexpressing golli, increased cell death was observed after mitogen withdrawal. This phenomenon could be prevented by exposure to VOCC (voltage-operated Ca2+ channel) blockers, indicating that the effect of golli on cell death involved increased Ca2+ influx through VOCCs. The results showed a clear effect of golli on OPC development and support a role for golli in modulating multiple Ca2+-regulatory events through VOCCs and SOCCs. Our results also suggest that PDGF engagement of its receptor resulting in OPC proliferation proceeds through activation of SOCCs.
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Matrix metalloproteinase proteolysis of the myelin basic protein isoforms is a source of immunogenic peptides in autoimmune multiple sclerosis. PLoS One 2009; 4:e4952. [PMID: 19300513 PMCID: PMC2654159 DOI: 10.1371/journal.pone.0004952] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Accepted: 02/18/2009] [Indexed: 01/09/2023] Open
Abstract
Background Matrix metalloproteinases (MMPs) play a significant role in the fragmentation of myelin basic protein (MBP) and demyelination leading to autoimmune multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE). The classic MBP isoforms are predominantly expressed in the oligodendrocytes of the CNS. The splice variants of the single MBP gene (Golli-MBP BG21 and J37) are widely expressed in the neurons and also in the immune cells. The relative contribution of the individual MMPs to the MBP cleavage is not known. Methodology/Principal Findings To elucidate which MMP plays the primary role in cleaving MBP, we determined the efficiency of MMP-2, MMP-8, MMP-9, MMP-10, MMP-12, MT1-MMP, MT2-MMP, MT3-MMP, MT4-MMP, MT5-MMP and MT6-MMP in the cleavage of the MBP, BG21 and J37 isoforms in the in vitro cleavage reactions followed by mass-spectroscopy analysis of the cleavage fragments. As a result, we identified the MMP cleavage sites and the sequence of the resulting fragments. We determined that MBP, BG21 and J37 are highly sensitive to redundant MMP proteolysis. MT6-MMP (initially called leukolysin), however, was superior over all of the other MMPs in cleaving the MBP isoforms. Using the mixed lymphocyte culture assay, we demonstrated that MT6-MMP proteolysis of the MBP isoforms readily generated, with a near quantitative yield, the immunogenic N-terminal 1–15 MBP peptide. This peptide selectively stimulated the proliferation of the PGPR7.5 T cell clone isolated from mice with EAE and specific for the 1–15 MBP fragment presented in the MHC H-2U context. Conclusions/Significance In sum, our biochemical observations led us to hypothesize that MT6-MMP, which is activated by furin and associated with the lipid rafts, plays an important role in MS pathology and that MT6-MMP is a novel and promising drug target in MS especially when compared with other individual MMPs.
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Perchellet A, Brabb T, Goverman JM. Crosspresentation by nonhematopoietic and direct presentation by hematopoietic cells induce central tolerance to myelin basic protein. Proc Natl Acad Sci U S A 2008; 105:14040-5. [PMID: 18772374 PMCID: PMC2544575 DOI: 10.1073/pnas.0804970105] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2008] [Indexed: 01/20/2023] Open
Abstract
Central tolerance plays a critical role in eliminating self-reactive T cells specific for peripheral antigens. Here we show that central tolerance of MHC class I-restricted T cells specific for classic myelin basic protein (MBP), a component of the myelin sheath, is mediated by both bone marrow (BM)-derived and nonBM-derived cells. Unexpectedly, BM-derived cells induce tolerance directly by using classic MBP that they synthesize, whereas nonBM-derived cells mediate tolerance by crosspresenting classic MBP acquired from an exogenous source. Thus, tolerance to tissue-specific antigens can involve multiple cell types and mechanisms in the thymus, which may account for the limited spectrum of autoimmune syndromes observed when expression of tissue-specific antigens is impaired only in thymic epithelial cells.
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Affiliation(s)
| | - Thea Brabb
- Comparative Medicine, University of Washington, Seattle, WA 98195
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Mellström B, Savignac M, Gomez-Villafuertes R, Naranjo JR. Ca2+-Operated Transcriptional Networks: Molecular Mechanisms and In Vivo Models. Physiol Rev 2008; 88:421-49. [DOI: 10.1152/physrev.00041.2005] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Calcium is the most universal signal used by living organisms to convey information to many different cellular processes. In this review we present well-known and recently identified proteins that sense and decode the calcium signal and are key elements in the nucleus to regulate the activity of various transcriptional networks. When possible, the review also presents in vivo models in which the genes encoding these calcium sensors-transducers have been modified, to emphasize the critical role of these Ca2+-operated mechanisms in many physiological functions.
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Polverini E, Rangaraj G, Libich DS, Boggs JM, Harauz G. Binding of the proline-rich segment of myelin basic protein to SH3 domains: spectroscopic, microarray, and modeling studies of ligand conformation and effects of posttranslational modifications. Biochemistry 2007; 47:267-82. [PMID: 18067320 DOI: 10.1021/bi701336n] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Myelin basic protein (MBP) is a multifunctional protein involved in maintaining the stability and integrity of the myelin sheath by a variety of interactions with membranes and with cytoskeletal and other proteins. A central segment of MBP is highly conserved in mammals and consists of a membrane surface-associated amphipathic alpha-helix, immediately followed by a proline-rich segment that we hypothesize is an SH3 ligand. We show by circular dichroic spectroscopy that this proline-rich segment forms a polyproline type II helix in vitro under physiological conditions and that phosphorylation at a constituent threonyl residue has a stabilizing effect on its conformation. Using SH3 domain microarrays, we observe that the unmodified recombinant murine 18.5 kDa MBP isoform (rmC1 component) binds the following SH3 domains: Yes1 > PSD95 > cortactin = PexD = Abl = Fyn = c-Src = Itk in order of decreasing affinity. A quasi-deiminated form of the protein (rmC8) binds the SH3 domains Yes1 > Fyn > cortactin = c-Src > PexD = Abl. Phosphorylation of rmC1 at 1-2 threonines within the proline-rich segment by mitogen-activated protein kinase in vitro has no effect on the binding specificity to the SH3 domains on the array. An SH3 domain of chicken Fyn is also demonstrated to bind to lipid membrane-associated C1, phosphorylated C1, and rmC8. Molecular docking simulations of the interaction of the putative SH3 ligand of classic MBP with the human Fyn SH3 domain indicate that the strength of the interaction is of the same order of magnitude as with calmodulin and that the molecular recognition and association is mediated by some weak CH...pi interactions between the ligand prolyl residues and the aromatic ones of the SH3 binding site. One such interaction is well-conserved and involves the stacking of an MBP-peptide prolyl and an SH3 domain tryptophanyl residue, as in most other SH3-ligand complexes. Lysyl and arginyl residues in the peptide canonically interact via salt bridges and cation-pi interactions with negatively charged and aromatic residues in the SH3 domain binding site. Posttranslational modifications (phosphorylation or methylation) of the ligand cause noticeable shifts in the conformation of the flexible peptide and its side chains but do not predict any major inhibition of the binding beyond somewhat less favorable interactions for peptides with phosphorylated seryl or threonyl residues.
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Affiliation(s)
- Eugenia Polverini
- Dipartimento di Fisica and CNISM, Università di Parma, V. le Usberti, 7/A, 43100 Parma, Italy
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Paez PM, Spreuer V, Handley V, Feng JM, Campagnoni C, Campagnoni AT. Increased expression of golli myelin basic proteins enhances calcium influx into oligodendroglial cells. J Neurosci 2007; 27:12690-9. [PMID: 18003849 PMCID: PMC6673339 DOI: 10.1523/jneurosci.2381-07.2007] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2007] [Revised: 09/28/2007] [Accepted: 10/01/2007] [Indexed: 11/21/2022] Open
Abstract
The myelin basic protein (MBP) gene encodes two families of proteins: the classic MBP constituents of myelin and the golli-MBPs, the function of which is less well understood. Previous work suggests that golli proteins may play a role in Ca2+ homeostasis in oligodendrocytes (OLs) and in T-cells. Overexpression of golli in OL cell lines induces elaboration of sheets and processes. Live imaging of these cells revealed a rapid retraction of the processes and sheets after depolarization with high K+. This phenomenon was associated with a significant increase in [Ca2+]int without changes in cell viability. The results indicated that golli produced its effect through Ca2+ influx, rather than Ca2+ release from intracellular stores. Furthermore, a specific [Ca2+]int chelator (BAPTA) or Cd2+, a specific blocker of voltage-operated Ca2+ channels, abolished the ability of golli to promote process extension in a dose-dependent manner. Analysis of the golli protein identified a myristoylation site at the C terminus of the golli domain, which was essential for the action of golli on Ca2+ influx, suggesting that binding of golli to the plasma membrane is important for modulating Ca2+ homeostasis. High-resolution spatiotemporal analysis along N19 processes revealed higher-amplitude local Ca2+ influx in regions with elevated levels of golli. These findings suggest a key role for golli proteins in regulating voltage-gated Ca2+ channels in OLs during process remodeling. Our observations are consistent with the hypothesis that golli proteins, as a part of a protein complex, modulate Ca2+ influx at the plasma membrane and along OL processes.
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Affiliation(s)
- Pablo M. Paez
- Semel Institute for Neuroscience and Human Behavior, University of California at Los Angeles Geffen Medical School, Los Angeles, California 90095
| | - Vilma Spreuer
- Semel Institute for Neuroscience and Human Behavior, University of California at Los Angeles Geffen Medical School, Los Angeles, California 90095
| | - Vance Handley
- Semel Institute for Neuroscience and Human Behavior, University of California at Los Angeles Geffen Medical School, Los Angeles, California 90095
| | - Ji-Ming Feng
- Semel Institute for Neuroscience and Human Behavior, University of California at Los Angeles Geffen Medical School, Los Angeles, California 90095
| | - Celia Campagnoni
- Semel Institute for Neuroscience and Human Behavior, University of California at Los Angeles Geffen Medical School, Los Angeles, California 90095
| | - Anthony T. Campagnoni
- Semel Institute for Neuroscience and Human Behavior, University of California at Los Angeles Geffen Medical School, Los Angeles, California 90095
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Ahmed MAM, Bamm VV, Harauz G, Ladizhansky V. The BG21 isoform of Golli myelin basic protein is intrinsically disordered with a highly flexible amino-terminal domain. Biochemistry 2007; 46:9700-12. [PMID: 17676872 DOI: 10.1021/bi700632x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The genes of the oligodendrocyte lineage (Golli) encode a family of developmentally regulated isoforms of myelin basic protein. The "classic" MBP isoforms arise from transcription start site 3, whereas Golli-specific isoforms arise from transcription start site 1, and comprise both Golli-specific and classic MBP sequences. The Golli isoform BG21 has been suggested to play roles in myelination and T cell activation pathways. It is an intrinsically disordered protein, thereby presenting a large effective surface area for interaction with other proteins such as Golli-interacting protein. We have used multidimensional heteronuclear NMR spectroscopy to achieve sequence-specific resonance assignments of the recombinant murine BG21 in physiologically relevant buffer, to analyze its secondary structure using chemical shift indexing (CSI), and to investigate its backbone dynamics using 15N spin relaxation measurements. We have assigned 184 out of 199 residues unambiguously. The CSI analysis revealed little ordered secondary structure under these conditions, with only some small fragments having a slight tendency toward alpha-helicity, which may represent putative recognition motifs. The 15N relaxation and NOE measurements confirmed the general behavior of the protein as an extended polypeptide chain, with the N-terminal Golli-specific portion (residues S5-T69) being exceptionally flexible, even in comparison to other intrinsically disordered proteins that have been studied this way. The high degree of flexibility of this N-terminal region may be to provide additional plasticity, or conformational adaptability, in protein-protein interactions. Another highly mobile segment, A126-S127-G128-G129, may function as a hinge.
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Affiliation(s)
- Mumdooh A M Ahmed
- Department of Physics and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada
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Bamm VV, Ahmed MAM, Ladizhansky V, Harauz G. Purification and spectroscopic characterization of the recombinant BG21 isoform of murine golli myelin basic protein. J Neurosci Res 2007; 85:272-84. [PMID: 17131428 DOI: 10.1002/jnr.21129] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A recombinant form of the murine Golli-myelin basic protein (MBP) isoform BG21 (rmBG21) has been expressed in E. coli, and isolated to 96% purity via metal chelation chromatography. Characteristic yields were 6-8 mg protein per liter of culture in either minimal M9 or standard Luria-Bertani media. Circular dichroism spectroscopy showed that rmBG21 had a large proportion of random coil in aqueous solution, but gained alpha-helix in the presence of monosialoganglioside G(M1) and PI(4)P, as well as in the membrane-mimetic solvent trifluoroethanol. Bioinformatics analyses of the amino acid sequence of rmBG21 predicted an N-terminal calmodulin (CaM)-binding site. It was determined by fluorescence spectroscopy and dynamic light scattering that rmBG21 and CaM interacted weakly in a 1:1 ratio in a Ca(2+)-dependent manner. Solution NMR spectra of uniformly [(13)C(15)N]-labeled protein in aqueous buffer were consistent with it being an extended protein; spectral quality was independent of temperature. Thus, like "classic" MBP and the Golli-MBP isoform J37, rmBG21 is intrinsically disordered, implying multi functionality, and that its conformation depends on its environment and bound ligands.
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Affiliation(s)
- Vladimir V Bamm
- Department of Molecular and Cellular Biology, University of Guelph, Ontario, Canada
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Kaga Y, Shoemaker WJ, Furusho M, Bryant M, Rosenbluth J, Pfeiffer SE, Oh L, Rasband M, Lappe-Siefke C, Yu K, Ornitz DM, Nave KA, Bansal R. Mice with conditional inactivation of fibroblast growth factor receptor-2 signaling in oligodendrocytes have normal myelin but display dramatic hyperactivity when combined with Cnp1 inactivation. J Neurosci 2006; 26:12339-50. [PMID: 17122059 PMCID: PMC6675428 DOI: 10.1523/jneurosci.3573-06.2006] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Fibroblast growth factor receptors (Fgfr) comprise a widely expressed family of developmental regulators implicated in oligodendrocyte (OL) maturation of the CNS. Fgfr2 is expressed by OLs in myelinated fiber tracks. In vitro, Fgfr2 is highly upregulated during OL terminal differentiation, and its activation leads to enhanced growth of OL processes and the formation of myelin-like membranes. To investigate the in vivo function of Fgfr2 signaling by myelinating glial cells, we inactivated the floxed Fgfr2 gene in mice that coexpress Cre recombinase (cre) as a knock-in gene into the OL-specific 2',3'-cyclic nucleotide phosphodiesterase (Cnp1) locus. Surprisingly, no obvious defects were detected in brain development of these conditional mutants, including the number of OLs, the onset and extent of myelination, the ultrastructure of myelin, and the expression level of myelin proteins. However, unexpectedly, a subset of these conditional Fgfr2 knock-out mice that are homozygous for cre and therefore are also Cnp1 null, displayed a dramatic hyperactive behavior starting at approximately 2 weeks of age. This hyperactivity was abolished by treatment with dopamine receptor antagonists or catecholamine biosynthesis inhibitors, suggesting that the symptoms involve a dysregulation of the dopaminergic system. Although the molecular mechanisms are presently unknown, this novel mouse model of hyperactivity demonstrates the potential involvement of OLs in neuropsychiatric disorders, as well as the nonpredictable role of genetic interactions in the behavioral phenotype of mice.
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MESH Headings
- 2',3'-Cyclic-Nucleotide Phosphodiesterases/deficiency
- 2',3'-Cyclic-Nucleotide Phosphodiesterases/metabolism
- 2',3'-Cyclic-Nucleotide Phosphodiesterases/physiology
- Animals
- Animals, Newborn
- Behavior, Animal
- Blotting, Western/methods
- Brain/cytology
- Cell Differentiation/genetics
- Dopamine Antagonists/pharmacology
- Dose-Response Relationship, Drug
- Fibroblast Growth Factor 2/deficiency
- Fibroblast Growth Factor 2/physiology
- Green Fluorescent Proteins/biosynthesis
- Green Fluorescent Proteins/genetics
- Hyperkinesis/genetics
- Hyperkinesis/physiopathology
- Immunohistochemistry/methods
- In Situ Hybridization/methods
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Microscopy, Electron, Transmission/methods
- Motor Activity/drug effects
- Motor Activity/physiology
- Myelin Basic Protein/metabolism
- Myelin Sheath/metabolism
- Myelin Sheath/ultrastructure
- Oligodendroglia/metabolism
- Oligodendroglia/ultrastructure
- Tyrosine 3-Monooxygenase/metabolism
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Affiliation(s)
- Y Kaga
- Department of Neuroscience, University of Connecticut Medical School, Farmington, Connecticut 06030, USA
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DeBruin LS, Haines JD, Bienzle D, Harauz G. Partitioning of myelin basic protein into membrane microdomains in a spontaneously demyelinating mouse model for multiple sclerosisThis paper is one of a selection of papers published in this Special Issue, entitled CSBMCB — Membrane Proteins in Health and Disease. Biochem Cell Biol 2006; 84:993-1005. [PMID: 17215885 DOI: 10.1139/o06-180] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
We have characterized the lipid rafts in myelin from a spontaneously demyelinating mouse line (ND4), and from control mice (CD1 background), as a function of age and severity of disease. Myelin was isolated from the brains of CD1 and ND4 mice at various ages, and cold lysed with 1.5% CHAPS (3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulphonate). The lysate was separated by low-speed centrifugation into supernatant and pellet fractions, which were characterized by Western blotting for myelin basic protein (MBP) isoforms and their post-translationally modified variants. We found that, with maturation and with disease progression, there was a specific redistribution of the 14–21.5 kDa MBP isoforms (classic exon-II-containing vs exon-II-lacking) and phosphorylated forms into the supernatant and pellet. Further fractionation of the supernatant to yield detergent-resistant membranes (DRMs), representing coalesced lipid rafts, showed these to be highly enriched in exon-II-lacking MBP isoforms, and deficient in methylated MBP variants, in mice of both genotypes. The DRMs from the ND4 mice appeared to be enriched in MBP phosphorylated by MAP kinase at Thr95 (murine 18.5 kDa numbering). These studies indicate that different splice isoforms and post-translationally modified charge variants of MBP are targeted to different microdomains in the myelin membrane, implying multifunctionality of this protein family in myelin maintenance.
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Affiliation(s)
- Lillian S DeBruin
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
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Delarasse C, Della Gaspera B, Lu CW, Lachapelle F, Gelot A, Rodriguez D, Dautigny A, Genain C, Pham-Dinh D. Complex alternative splicing of the myelin oligodendrocyte glycoprotein gene is unique to human and non-human primates. J Neurochem 2006; 98:1707-17. [PMID: 16903876 DOI: 10.1111/j.1471-4159.2006.04053.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Myelin/oligodendrocyte glycoprotein (MOG) is a minor integral membrane protein specific to CNS myelin, encoded by a gene located in the major histocompatibility complex. MOG is an highly encephalitogenic autoantigen and a target for autoaggressive immune responses in CNS inflammatory demyelinating diseases. We performed transcriptomic analyses for a gene expressed only in mammalian CNS, myelin oligodendrocyte glycoprotein (MOG). Complex splicing patterns were exclusively found in primates and not in mice, unlike patterns found for other myelin protein genes. In addition to those shared with rodents, these multiple MOG isoforms likely support functions unique to the primate order, in particular maintenance of myelin structure, intracellular signaling, and modulation of CNS autoimmunity via exposure of specific MOG determinants. Developmentally, in human brain the splice variants of MOG appear at a late stage compared to the major isoform, coincidental with myelination and myelin maturation, unlike other myelin proteins. These findings are discussed within the framework of a biological basis for phenotype diversity in recent mammalian evolution and for the notoriously variable clinical expression of diseases such as multiple sclerosis.
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Feng JM, Hu YK, Xie LH, Colwell CS, Shao XM, Sun XP, Chen B, Tang H, Campagnoni AT. Golli protein negatively regulates store depletion-induced calcium influx in T cells. Immunity 2006; 24:717-727. [PMID: 16782028 DOI: 10.1016/j.immuni.2006.04.007] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2005] [Revised: 02/24/2006] [Accepted: 04/05/2006] [Indexed: 11/28/2022]
Abstract
Calcium influx is crucial for T cell activation and differentiation. The detailed regulation of this process remains unclear. We report here that golli protein, an alternatively spliced product of the myelin basic protein gene, plays a critical role in regulating calcium influx in T cells. Golli-deficient T cells were hyperproliferative and showed enhanced calcium entry upon T cell receptor stimulation. We further found that golli regulates calcium influx in T cells through the inhibition of the store depletion-induced calcium influx. Mutation of the myristoylation site on golli disrupted its association with the plasma membrane and reversed its inhibitory action on Ca2+ influx, indicating that membrane association of golli was essential for its inhibitory action. These results indicate that golli functions in a unique way to regulate T cell activation through a mechanism involving the modulation of the calcium homeostasis.
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Affiliation(s)
- Ji-Ming Feng
- Semel Institute of Neuroscience and Human Behavior, UCLA Geffen School of Medicine, 635 Charles Young Drive, Los Angeles, California 90095.
| | - Yanhong K Hu
- Semel Institute of Neuroscience and Human Behavior, UCLA Geffen School of Medicine, 635 Charles Young Drive, Los Angeles, California 90095
| | - Lai-Hua Xie
- Department of Cardiology, UCLA Geffen School of Medicine, 635 Charles Young Drive, Los Angeles, California 90095
| | - Christopher S Colwell
- Semel Institute of Neuroscience and Human Behavior, UCLA Geffen School of Medicine, 635 Charles Young Drive, Los Angeles, California 90095
| | - Xuesi M Shao
- Department of Neurobiology, UCLA Geffen School of Medicine, 635 Charles Young Drive, Los Angeles, California 90095
| | - Xiao-Ping Sun
- Department of Physiology, UCLA Geffen School of Medicine, 635 Charles Young Drive, Los Angeles, California 90095
| | - Boming Chen
- Department of Physiology, UCLA Geffen School of Medicine, 635 Charles Young Drive, Los Angeles, California 90095
| | - Hezhen Tang
- Semel Institute of Neuroscience and Human Behavior, UCLA Geffen School of Medicine, 635 Charles Young Drive, Los Angeles, California 90095
| | - Anthony T Campagnoni
- Semel Institute of Neuroscience and Human Behavior, UCLA Geffen School of Medicine, 635 Charles Young Drive, Los Angeles, California 90095.
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