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Grassi S, Cabitta L, Prioni S, Mauri L, Ciampa MG, Yokoyama N, Iwabuchi K, Zorina Y, Prinetti A. Identification of the Lipid Antigens Recognized by rHIgM22, a Remyelination-Promoting Antibody. Neurochem Res 2023; 48:1783-1797. [PMID: 36695984 DOI: 10.1007/s11064-023-03859-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 11/22/2022] [Accepted: 01/09/2023] [Indexed: 01/26/2023]
Abstract
Failure of the immune system to discriminate myelin components from foreign antigens plays a critical role in the pathophysiology of multiple sclerosis. In fact, the appearance of anti-myelin autoantibodies, targeting both proteins and glycolipids, is often responsible for functional alterations in myelin-producing cells in this disease. Nevertheless, some of these antibodies were reported to be beneficial for remyelination. Recombinant human IgM22 (rHIgM22) binds to myelin and to the surface of O4-positive oligodendrocytes, and promotes remyelination in mouse models of chronic demyelination. Interestingly, the identity of the antigen recognized by this antibody remains to be elucidated. The preferential binding of rHIgM22 to sulfatide-positive cells or tissues suggests that sulfatide might be part of the antigen pattern recognized by the antibody, however, cell populations lacking sulfatide expression are also responsive to rHIgM22. Thus, we assessed the binding of rHIgM22 in vitro to purified lipids and lipid extracts from various sources to identify the antigen(s) recognized by this antibody. Our results show that rHIgM22 is indeed able to bind both sulfatide and its deacylated form, whereas no significant binding for other myelin sphingolipids has been detected. Remarkably, binding of rHIgM22 to sulfatide in lipid monolayers can be positively or negatively regulated by the presence of other lipids. Moreover, rHIgM22 also binds to phosphatidylinositol, phosphatidylserine and phosphatidic acid, suggesting that not only sulfatide, but also other membrane lipids might play a role in the binding of rHIgM22 to oligodendrocytes and to other cell types not expressing sulfatide.
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Affiliation(s)
- Sara Grassi
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Via Fratelli Cervi 93, Segrate, 20090, Milan, Italy.
| | - Livia Cabitta
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Via Fratelli Cervi 93, Segrate, 20090, Milan, Italy
| | - Simona Prioni
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Via Fratelli Cervi 93, Segrate, 20090, Milan, Italy
| | - Laura Mauri
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Via Fratelli Cervi 93, Segrate, 20090, Milan, Italy
| | - Maria Grazia Ciampa
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Via Fratelli Cervi 93, Segrate, 20090, Milan, Italy
| | - Noriko Yokoyama
- Institute for Environmental and Gender Specific Medicine, Graduate School of Medicine, Juntendo University, Urayasu, Chiba, Japan
| | - Kazuhisa Iwabuchi
- Institute for Environmental and Gender Specific Medicine, Graduate School of Medicine, Juntendo University, Urayasu, Chiba, Japan
| | | | - Alessandro Prinetti
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Via Fratelli Cervi 93, Segrate, 20090, Milan, Italy
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Zhu J, Guo X, Ran N, Liang J, Liu F, Liu J, Wang R, Jiang L, Yang D, Liu M. Leukoencephalopathy hypomyelination with brainstem and spinal cord involvement and leg spasticity caused by DARS1 mutations. Front Genet 2023; 13:1009230. [PMID: 36712860 PMCID: PMC9878823 DOI: 10.3389/fgene.2022.1009230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 11/15/2022] [Indexed: 01/13/2023] Open
Abstract
Hypomyelination with brainstem and spinal cord involvement and leg spasticity (HBSL), caused by aspartyl-tRNA synthetase (DARS1) gene mutations, is extremely rare, with only a few cases reported worldwide; thus, reports on HBSL treatment are few. In this review, we summarized the clinical manifestations, imaging features, treatment methods, and gene mutations responsible for HBSL based on relevant studies and cases.
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Affiliation(s)
- Jingyi Zhu
- Neurology Department, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Xiaomin Guo
- Neurology Department, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Ningjing Ran
- Neurology Department, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Jingtao Liang
- Neurology Department, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Fuyou Liu
- Neurology Department, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Junyan Liu
- School of Clinical Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Rongyu Wang
- School of Clinical Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Lianyan Jiang
- School of Clinical Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Dongdong Yang
- Neurology Department, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China,*Correspondence: Meijun Liu, ; Dongdong Yang,
| | - Meijun Liu
- Neurology Department, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China,*Correspondence: Meijun Liu, ; Dongdong Yang,
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Grassi S, Mauri L, Prioni S, Cabitta L, Sonnino S, Prinetti A, Giussani P. Sphingosine 1-Phosphate Receptors and Metabolic Enzymes as Druggable Targets for Brain Diseases. Front Pharmacol 2019; 10:807. [PMID: 31427962 PMCID: PMC6689979 DOI: 10.3389/fphar.2019.00807] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 06/21/2019] [Indexed: 12/12/2022] Open
Abstract
The central nervous system is characterized by a high content of sphingolipids and by a high diversity in terms of different structures. Stage- and cell-specific sphingolipid metabolism and expression are crucial for brain development and maintenance toward adult age. On the other hand, deep dysregulation of sphingolipid metabolism, leading to altered sphingolipid pattern, is associated with the majority of neurological and neurodegenerative diseases, even those totally lacking a common etiological background. Thus, sphingolipid metabolism has always been regarded as a promising pharmacological target for the treatment of brain disorders. However, any therapeutic hypothesis applied to complex amphipathic sphingolipids, components of cellular membranes, has so far failed probably because of the high regional complexity and specificity of the different biological roles of these structures. Simpler sphingosine-based lipids, including ceramide and sphingosine 1-phosphate, are important regulators of brain homeostasis, and, thanks to the relative simplicity of their metabolic network, they seem a feasible druggable target for the treatment of brain diseases. The enzymes involved in the control of the levels of bioactive sphingoids, as well as the receptors engaged by these molecules, have increasingly allured pharmacologists and clinicians, and eventually fingolimod, a functional antagonist of sphingosine 1-phosphate receptors with immunomodulatory properties, was approved for the therapy of relapsing-remitting multiple sclerosis. Considering the importance of neuroinflammation in many other brain diseases, we would expect an extension of the use of such analogs for the treatment of other ailments in the future. Nevertheless, many aspects other than neuroinflammation are regulated by bioactive sphingoids in healthy brain and dysregulated in brain disease. In this review, we are addressing the multifaceted possibility to address the metabolism and biology of bioactive sphingosine 1-phosphate as novel targets for the development of therapeutic paradigms and the discovery of new drugs.
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Affiliation(s)
- Sara Grassi
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Laura Mauri
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Simona Prioni
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Livia Cabitta
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Sandro Sonnino
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Alessandro Prinetti
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Paola Giussani
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
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4
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Fereidan-Esfahani M, Nayfeh T, Warrington A, Howe CL, Rodriguez M. IgM Natural Autoantibodies in Physiology and the Treatment of Disease. Methods Mol Biol 2019; 1904:53-81. [PMID: 30539466 DOI: 10.1007/978-1-4939-8958-4_3] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Antibodies are vital components of the adaptive immune system for the recognition and response to foreign antigens. However, some antibodies recognize self-antigens in healthy individuals. These autoreactive antibodies may modulate innate immune functions. IgM natural autoantibodies (IgM-NAAs) are a class of primarily polyreactive immunoglobulins encoded by germline V-gene segments which exhibit low affinity but broad specificity to both foreign and self-antigens. Historically, these autoantibodies were closely associated with autoimmune disease. Nevertheless, not all human autoantibodies are pathogenic and compelling evidence indicates that IgM-NAAs may exert a spectrum of effects from injurious to protective depending upon cellular and molecular context. In this chapter, we review the current state of knowledge regarding the potential physiological and therapeutic roles of IgM-NAAs in different disease conditions such as atherosclerosis, cancer, and autoimmune disease. We also describe the discovery of two reparative IgM-NAAs by our laboratory and delineate their proposed mechanisms of action in central nervous system (CNS) disease.
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Affiliation(s)
| | - Tarek Nayfeh
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | | | - Charles L Howe
- Department of Neurology, Mayo Clinic, Rochester, MN, USA.
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5
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Human Remyelination Promoting Antibody Stimulates Astrocytes Proliferation Through Modulation of the Sphingolipid Rheostat in Primary Rat Mixed Glial Cultures. Neurochem Res 2018; 44:1460-1474. [PMID: 30569280 DOI: 10.1007/s11064-018-2701-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 11/22/2018] [Accepted: 12/12/2018] [Indexed: 01/17/2023]
Abstract
Remyelination promoting human IgMs effectively increase the number of myelinated axons in animal models of multiple sclerosis. Hence, they ultimately stimulate myelin production by oligodendrocytes (OLs); however, their exact mechanism of action remains to be elucidated, and in particular, it remains unclear whether they are directly targeting OLs, or their action is mediated by effects on other cell types. We assessed the effect of remyelination promoting antibody rHIgM22 on the proliferative response and on the ceramide/sphingosine 1-phosphate rheostat in mixed glial cell cultures (MGCs). rHIgM22 treatment caused a time-dependent increase in PDGFαR protein in MGCs. Forty-eight hours of treatment with rHIgM22 induced a dose-dependent proliferative response (evaluated as total cell number and as EdU(+) cell number) in MGCs. When the proliferation response of MGCs to rHIgM22 was analyzed as a function of the cell types, the most significant proliferative response was associated with GLAST(+) cells, i.e., astrocytes. In many cell types, the balance between different sphingolipid mediators (the "sphingolipid rheostat"), in particular ceramide and sphingosine 1-phosphate, is critical in determining the cell fate. rHIgM22 treatment in MGCs induced a moderate but significant inhibition of total acidic sphingomyelinase activity (measured in vitro on cell lysates), the main enzyme responsible for the stimulus-mediated production of ceramide, when treatment was performed in serum containing medium, but no significant differences were observed when antibody treatment was performed in the absence of serum. Moreover, rHIgM22 treatment, either in the presence or in absence of serum, had no effects on ceramide levels. On the other hand, rHIgM22 treatment for 24 h induced increased production and release of sphingosine 1-phosphate in the extracellular milieu of MGC. Release of sphingosine 1-phosphate upon rHIgM22 treatment was strongly reduced by a selective inhibitor of PDGFαR. Increased sphingosine 1-phosphate production does not seem to be mediated by regulation of the biosynthetic enzymes, sphingosine kinase 1 and 2, since protein levels of these enzymes and phosphorylation of sphingosine kinase 1 were unchanged upon rHIgM22 treatment. Instead, we observed a significant reduction in the levels of sphingosine 1-phosphate lyase 1, one of the key catabolic enzymes. Remarkably, rHIgM22 treatment under the same experimental conditions did not induce changes in the production and/or release of sphingosine 1-phosphate in pure astrocyte cultures. Taken together, these data suggest that rHIgM22 indirectly influences the proliferation of astrocytes in MGCs, by affecting the ceramide/sphingosine 1-phosphate balance. The specific cell population directly targeted by rHIgM22 remains to be identified, however our study unveils another aspect of the complexity of rHIgM22-induced remyelinating effect.
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Human IgM antibody rHIgM22 promotes phagocytic clearance of myelin debris by microglia. Sci Rep 2018; 8:9392. [PMID: 29925848 PMCID: PMC6010437 DOI: 10.1038/s41598-018-27559-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 06/01/2018] [Indexed: 12/12/2022] Open
Abstract
In multiple sclerosis (MS), demyelinated CNS lesions fail to sufficiently remyelinate, despite the presence of oligodendrocyte precursor cells (OPCs) capable of differentiating into mature oligodendrocytes. MS lesions contain damaged myelin debris that can inhibit OPC maturation and hinder repair. rHIgM22 is an experimental human recombinant IgM antibody that promotes remyelination in animal models and is being examined in patients with MS. rHIgM22 binds to CNS myelin and partially rescues OPC process outgrowth on myelin. Since rHIgM22 does not affect OPC process outgrowth in vitro on permissive substrate, we examined the possibility that it acts by enhancing phagocytic clearance of myelin debris by microglia. In this study, we tested if rHIgM22 binding could tag myelin for microglial phagocytosis. A mouse microglial cell line and primary rat microglia were treated with myelin and rHIgM22 and assayed for myelin phagocytosis. We found that: 1) rHIgM22 stimulates myelin phagocytosis in a dose-dependent manner; 2) rHIgM22-mediated myelin phagocytosis requires actin polymerization; and 3) rHIgM22-stimulation of myelin phagocytosis requires activity of rHIgM22 Fc domain and activation of Complement Receptor 3. Since myelin inhibits OPC differentiation, stimulation of phagocytic clearance of damaged myelin may be an important means by which rHIgM22 promotes remyelination.
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Perwein MK, Smestad JA, Warrington AE, Heider RM, Kaczor MW, Maher LJ, Wootla B, Kunbaz A, Rodriguez M. A comparison of human natural monoclonal antibodies and aptamer conjugates for promotion of CNS remyelination: where are we now and what comes next? Expert Opin Biol Ther 2018; 18:545-560. [PMID: 29460650 DOI: 10.1080/14712598.2018.1441284] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
INTRODUCTION Multiple sclerosis (MS) is a chronic and progressive inflammatory demyelinating disease of the human central nervous system (CNS) and is the most common disabling neurological condition in young adults, resulting in severe neurological defects. No curative or long-term progression-inhibiting therapy has yet been developed. However, recent investigation has revealed potential strategies that do not merely modulate potentially pathogenic autoimmune responses, but stimulate remyelination within CNS lesions. AREAS COVERED We discuss the history and development of natural human IgM-isotype immunoglobulins (HIgMs) and recently-identified aptamer-conjugates that have been shown to enhance endogenous myelin repair in animal models of demyelination by acting on myelin-producing oligodendrocytes (OLs) or oligodendrocyte progenitor cells (OPCs) within CNS lesions. We also discuss future development aims and applications for these important novel technologies. EXPERT OPINION Aptamer conjugate Myaptavin-3064 and recombinant human IgM-isotype antibody rHIgM22 regenerate CNS myelin, thereby reducing axonal degeneration and offering the potential of recovery from MS relapses, reversal of disability and prevention of disease progression. Advancement of these technologies into the clinic for MS treatment is therefore a top priority. It remains unclear to what extent the therapeutic modalities of remyelinating antibodies and aptamers may synergize with other currently-approved therapies to yield enhanced therapeutic effects.
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Affiliation(s)
- Maria K Perwein
- a Department of Neurology , Mayo Clinic College of Medicine and Science , Rochester , MN , USA
| | - John A Smestad
- b Medical Scientist Training Program , Mayo Clinic College of Medicine and Science , Rochester , MN , USA.,c Department of Biochemistry and Molecular Biology , Mayo Clinic College of Medicine and Science , Rochester , MN , USA
| | - Arthur E Warrington
- a Department of Neurology , Mayo Clinic College of Medicine and Science , Rochester , MN , USA
| | - Robin M Heider
- c Department of Biochemistry and Molecular Biology , Mayo Clinic College of Medicine and Science , Rochester , MN , USA
| | - Mark W Kaczor
- a Department of Neurology , Mayo Clinic College of Medicine and Science , Rochester , MN , USA
| | - Louis J Maher
- c Department of Biochemistry and Molecular Biology , Mayo Clinic College of Medicine and Science , Rochester , MN , USA
| | - Bharath Wootla
- a Department of Neurology , Mayo Clinic College of Medicine and Science , Rochester , MN , USA
| | - Ahmad Kunbaz
- a Department of Neurology , Mayo Clinic College of Medicine and Science , Rochester , MN , USA
| | - Moses Rodriguez
- a Department of Neurology , Mayo Clinic College of Medicine and Science , Rochester , MN , USA.,d Department of Immunology , Mayo Clinic College of Medicine and Science , Rochester , MN , USA
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8
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Kunbaz A, Warrington AE, Perwein MK, Fereidan-Esfahani M, Rodriguez M. A natural human monoclonal antibody protects from axonal injury in different CNS degenerative disease models. FUTURE NEUROLOGY 2018. [DOI: 10.2217/fnl-2017-0027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Axon regeneration after CNS injury is incomplete. This is partially due to the presence of multiple growth inhibitory molecules within myelin that prevent axonal extension. These inhibitors include myelin-associated glycoprotein, Nogo and oligodendrocyte myelin glycoprotein. A natural human recombinant antibody, rHIgM12, was identified by its ability to promote neurite outgrowth in vitro. rHIgM12 overrides the neurite outgrowth inhibition of myelin by binding with high affinity to neuronal PSA-NCAM and gangliosides. This neurite outgrowth is accompanied by increased α-tubulin tyrosination and decreased acetylation which occurs after treatment with rHIgM12. rHIgM12 is efficacious in murine models of human multiple sclerosis and amyotrophic lateral sclerosis, improving axon survival and neurologic function. rHIgM12 has great promise as a therapeutic molecule in a number of CNS disorders characterized by neuronal loss and axonal transection including multiple sclerosis. This review will focus on rHIgM12 discovery, effects in preclinical models and potential applications as a therapeutic reagent for CNS disease.
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Affiliation(s)
- Ahmad Kunbaz
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
| | | | - Maria K Perwein
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
| | | | - Moses Rodriguez
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
- Department of Immunology, Mayo Clinic, Rochester, MN 55905, USA
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Timing of Future Remyelination Therapies and Their Potential to Stop Multiple Sclerosis Progression. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 958:161-170. [PMID: 28093713 DOI: 10.1007/978-3-319-47861-6_10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Prior to the onset of demyelination in multiple sclerosis (MS), early oligodendrocyte injury, axonal degeneration and astroglial scarring occur. The irreversible progressive phase of MS begins when the axonal loss threshold is reached. Progressive disease onset has the highest impact on a poor prognosis in MS. Conversion to progressive disease is essentially an age-dependent process independent of disease duration and initial disease course. Although prevention of relapses has been the primary approach in the disease management, incomplete recovery from even the first relapse correlates with the long-term neurodegenerative phenotype of progressive MS onset. Therefore, the provider should review each patient's potential for relapse-related disability and start DMDs with the goal of preventing relapses. Existing immunomodulatory medications used to prevent MS relapses do not prevent long-term disability, which requires agents focused on remyelination and axonal repair. If applied immediately after a relapse rather than during the progressive phase of MS, remyelination-stimulating strategies may result in full recovery and prevention of long-term neurodegeneration and progressive disease course.
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Mullin AP, Cui C, Wang Y, Wang J, Troy E, Caggiano AO, Parry TJ, Colburn RW, Pavlopoulos E. rHIgM22 enhances remyelination in the brain of the cuprizone mouse model of demyelination. Neurobiol Dis 2017; 105:142-155. [DOI: 10.1016/j.nbd.2017.05.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Revised: 05/04/2017] [Accepted: 05/29/2017] [Indexed: 02/02/2023] Open
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Lemus HN, Warrington AE, Denic A, Wootla B, Rodriguez M. Treatment with a recombinant human IgM that recognizes PSA-NCAM preserves brain pathology in MOG-induced experimental autoimmune encephalomyelitis. Hum Antibodies 2017; 25:121-129. [PMID: 28269761 DOI: 10.3233/hab-170313] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A single peripheral dose of CNS-binding IgMs promote remyelination and preserve axons in a number of animal models of neurologic disease. A myelin-binding recombinant human IgM (rHIgM22) is presently in a safety trial in MS patients following an acute MS exacerbation. rHIgM22 (directed against oligodendrocytes) or rHIgM12 (directed against neurons) were administered to mice with MOG-induced experimental autoimmune encephalomyelitis (EAE) with study endpoints: clinical deficits and brain and spinal cord pathology. IgMs were administered at a therapeutic dose of 100 μ g intra peritoneal at the time of immunization (day -1, 0, +$1), disease onset (15 days) or peak of the disease (28 days). Disease course was not worsened by either human IgM regardless of the time of treatment. Of note, the human IgM that recognizes a carbohydrate epitope on gangliosides and NCAM, rHIgM12, reduced brain pathology when given at time of immunization or at onset of disease, but did not reduce clinical deficits or spinal cord disease burden. Hence, treatment with rHIgM12 resulted in marked reduction in meningeal inflammation. Data consistent with the hypothesis that in the EAE model this molecule has an immune-modulatory effect. Treatment with an anti-CD4 blocking IgG prevented both clinical course and CNS pathology. This pre-clinical study further supports the safety of therapeutic CNS-binding human IgMs in the presence of autoimmunity and clearly differentiates them from IgGs directed against MOG or aquaporin-4 that worsen neurologic disease.
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MESH Headings
- Animals
- Brain/drug effects
- Brain/immunology
- Brain/pathology
- Cognitive Dysfunction/chemically induced
- Cognitive Dysfunction/drug therapy
- Cognitive Dysfunction/immunology
- Cognitive Dysfunction/pathology
- Demyelinating Diseases/chemically induced
- Demyelinating Diseases/drug therapy
- Demyelinating Diseases/immunology
- Demyelinating Diseases/pathology
- Drug Administration Schedule
- Encephalomyelitis, Autoimmune, Experimental/chemically induced
- Encephalomyelitis, Autoimmune, Experimental/drug therapy
- Encephalomyelitis, Autoimmune, Experimental/immunology
- Encephalomyelitis, Autoimmune, Experimental/pathology
- Female
- Freund's Adjuvant/administration & dosage
- Humans
- Immunoglobulin M/pharmacology
- Immunologic Factors/pharmacology
- Injections, Intraperitoneal
- Mice
- Mice, Inbred C57BL
- Myelin Sheath/drug effects
- Myelin Sheath/immunology
- Myelin Sheath/pathology
- Myelin-Oligodendrocyte Glycoprotein/administration & dosage
- Neural Cell Adhesion Molecule L1/immunology
- Neural Cell Adhesion Molecule L1/metabolism
- Neurons/drug effects
- Neurons/immunology
- Neurons/pathology
- Neuroprotective Agents/pharmacology
- Oligodendroglia/drug effects
- Oligodendroglia/immunology
- Oligodendroglia/pathology
- Peptide Fragments/administration & dosage
- Protein Binding
- Recombinant Proteins/pharmacology
- Sialic Acids/immunology
- Sialic Acids/metabolism
- Spinal Cord/drug effects
- Spinal Cord/immunology
- Spinal Cord/pathology
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Affiliation(s)
| | | | | | - Bharath Wootla
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
| | - Moses Rodriguez
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
- Department of Immunology, Mayo Clinic, Rochester, MN 55905, USA
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12
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Kumar N, Rodriguez M. Scleromyxedema in a patient with multiple sclerosis and monoclonal gammopathy on interferon beta-1a. Mult Scler 2016; 10:85-6. [PMID: 14760958 DOI: 10.1191/1352458504ms987cr] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Background: Animal studies have shown that some human monoclonal antibodies promote myelin repair in models of demyelinating disease. Scleromyxedema is a dermatologic disorder associated with a monoclonal gammopathy and neurologic manifestations. The reason for occurrence of cutaneous reactio ns in interferon treated patients is unknown. Case description: A 37-year-o ld woman was started on weekly interferon beta-1a (IFN beta-1a) following a diagnosis of multiple sclerosis (MS). A fter having been on interferon therapy for three years, she developed skin lesions secondary to scleromyxedema. Her IFN beta-1a was discontinued and intravenous immunoglobulin therapy was started for her scleromyxedema. A t a six-month follow up, her skin lesions improved and there was no recurrence of neurologic symptoms. Conclusions: This is the first report of occurrence of scleromyxedema in a patient with MS. While this could be a chance association, it does raise the question if her neurologic manifestations could be secondary to scleromyxedema. Further research into the mechanism of IFN related cutaneo us side effects is needed. Evidence regarding the remyelinating nature of human monoclonal antibodies raises interest in the potential therapeutic role these antibodies may have.
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Affiliation(s)
- Neeraj Kumar
- Department of Neurology, Mayo Medical and Graduate Schools, Rochester, MN 55905, USA.
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13
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Dasari H, Wootla B, Warrington AE, Rodriguez M. Concomitant Use of Neuroprotective Drugs in Neuro Rehabilitation of Multiple Sclerosis. ACTA ACUST UNITED AC 2016; 4. [PMID: 27595123 PMCID: PMC5006625 DOI: 10.4172/2329-9096.1000348] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We provide an overview of rehabilitation in neurological diseases. A large amount of literature available on neurorehabilitation is based from the rehabilitative work on stroke and spinal cord injuries. After a brief description of rehabilitation, the potential application of neurorehabilitation in neurodegenerative diseases specifically multiple sclerosis (MS) is summarized. Since MS causes a wide variety of symptoms, the rehabilitation in MS patients may benefit from an interdisciplinary approach that encloses physiotherapy, cognitive rehabilitation, psychological therapy, occupational therapy, and other methods to improve fatigue. Neurorehabilitation helps patients to reach and maintain their optimal physical, psychological and intellectual, levels but it does not reverse long-term disabilities that arise from neurological disorders. This calls for the need of better neuroregenerative and neuroprotective treatment strategies in addition to neurorehabilitation. We discuss neuroprotective drugs aimed at preventing axonal, neuronal, myelin and oligodendrocyte damage and cell death that are approved and others that are currently in clinical trials, with an emphasis on human derived natural antibodies with remyleination potential. Our investigative group developed recombinant natural human IgM antibodies against oligodendrocytes and neurons with a potential for CNS repair and remyleination. One such recombinant antibody, rHIgM22 completed a phase 1 clinical trial with no toxicity and with an objective of promoting remyleination in multiple sclerosis. Inclusion of these drugs as a multifaceted approach may further enhance the efficacy of neurorehabilitation in neuroinflammatory and neurodegenerative disorders.
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Affiliation(s)
- Harika Dasari
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA; Mayo Clinic Center for Multiple Sclerosis and Autoimmune Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Bharath Wootla
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA; Mayo Clinic Center for Multiple Sclerosis and Autoimmune Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Arthur E Warrington
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA; Mayo Clinic Center for Multiple Sclerosis and Autoimmune Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Moses Rodriguez
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA; Mayo Clinic Center for Multiple Sclerosis and Autoimmune Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA; Department of Immunology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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14
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Olsen JA, Akirav EM. Remyelination in multiple sclerosis: Cellular mechanisms and novel therapeutic approaches. J Neurosci Res 2014; 93:687-96. [DOI: 10.1002/jnr.23493] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 09/05/2014] [Accepted: 09/11/2014] [Indexed: 12/20/2022]
Affiliation(s)
- John A. Olsen
- Research Institute, Islet Biology; Winthrop-University Hospital; Mineola New York
| | - Eitan M. Akirav
- Research Institute, Islet Biology; Winthrop-University Hospital; Mineola New York
- Stony Brook University School of Medicine; Stony Brook New York
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15
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Watzlawik JO, Wootla B, Painter MM, Warrington AE, Rodriguez M. Cellular targets and mechanistic strategies of remyelination-promoting IgMs as part of the naturally occurring autoantibody repertoire. Expert Rev Neurother 2014; 13:1017-29. [PMID: 24053345 DOI: 10.1586/14737175.2013.835601] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Immunoglobulins with germline sequences occur in invertebrates and vertebrates and are named naturally occurring autoantibodies (NAbs). NAbs may target foreign antigens, self- or altered self-components and are part of the normal immunoglobulin repertoire. Accumulating evidence indicates that naturally occurring antibodies can act as systemic surveillance molecules, which tag, damaged or stressed cells, invading pathogens and toxic cellular debris for elimination by the immune system. In addition to acting as detecting molecules, certain types of NAbs actively signal in different cell types with a broad range of responses from induction of apoptosis in cancer cells to stimulation of remyelination in glial cells. This review emphasizes functions and characteristics of NAbs with focus on remyelination-promoting mouse and human antibodies. Human remyelination-promoting NAbs are potential therapeutics to combat a wide spectrum of disease processes including demyelinating diseases like multiple sclerosis. We will highlight the identified glycosphingolipid (SL) antigens of polyreactive remyelination-promoting antibodies and their proposed mechanism(s) of action. The nature of the identified antigens suggests a lipid raft-based mechanism for remyelination-promoting antibodies with SLs as most essential raft components. However, accumulating evidence also suggests involvement of other antigens in stimulation of remyelination, which will be discussed in the text.
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Affiliation(s)
- Jens O Watzlawik
- Departments of Neurology and Immunology, Mayo Clinic, College of Medicine, 200 First Street, S.W., Rochester, MN 55905, USA
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16
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Wittenberg NJ, Wootla B, Jordan LR, Denic A, Warrington AE, Oh SH, Rodriguez M. Applications of SPR for the characterization of molecules important in the pathogenesis and treatment of neurodegenerative diseases. Expert Rev Neurother 2014; 14:449-63. [PMID: 24625008 PMCID: PMC3989105 DOI: 10.1586/14737175.2014.896199] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Characterization of binding kinetics and affinity between a potential drug and its receptor are key steps in the development of new drugs. Among the techniques available to determine binding affinities, surface plasmon resonance has emerged as the gold standard because it can measure binding and dissociation rates in real-time in a label-free fashion. Surface plasmon resonance is now finding applications in the characterization of molecules for treatment of neurodegenerative diseases, characterization of molecules associated with pathogenesis of neurodegenerative diseases and detection of neurodegenerative disease biomarkers. In addition it has been used in the characterization of a new class of natural autoantibodies that have therapeutic potential in a number of neurologic diseases. In this review we will introduce surface plasmon resonance and describe some applications of the technique that pertain to neurodegenerative disorders and their treatment.
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Affiliation(s)
- Nathan J. Wittenberg
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN USA
| | - Bharath Wootla
- Department of Neurology, Mayo Clinic College of Medicine, Rochester, MN USA
| | - Luke R. Jordan
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN USA
| | - Aleksandar Denic
- Department of Neurology, Mayo Clinic College of Medicine, Rochester, MN USA
| | | | - Sang-Hyun Oh
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN USA
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN USA
| | - Moses Rodriguez
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN USA
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN USA
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17
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Role of galactosylceramide and sulfatide in oligodendrocytes and CNS myelin: formation of a glycosynapse. ADVANCES IN NEUROBIOLOGY 2014; 9:263-91. [PMID: 25151383 DOI: 10.1007/978-1-4939-1154-7_12] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The two major glycosphingolipids of myelin, galactosylceramide (GalC) and sulfatide (SGC), interact with each other by trans carbohydrate-carbohydrate interactions in vitro. They face each other in the apposed extracellular surfaces of the multilayered myelin sheath produced by oligodendrocytes and could also contact each other between apposed oligodendrocyte processes. Multivalent galactose and sulfated galactose, in the form of GalC/SGC-containing liposomes or silica nanoparticles conjugated to galactose and galactose-3-sulfate, interact with GalC and SGC in the membrane sheets of oligodendrocytes in culture. This interaction causes transmembrane signaling, loss of the cytoskeleton and clustering of membrane domains, similar to the effects of cross-linking by anti-GalC and anti-SGC antibodies. These effects suggest that GalC and SGC could participate in glycosynapses, similar to neural synapses or the immunological synapse, between GSL-enriched membrane domains in apposed oligodendrocyte membranes or extracellular surfaces of mature myelin. Formation of such glycosynapses in vivo would be important for myelination and/or oligodendrocyte/myelin function.
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18
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Myelin recovery in multiple sclerosis: the challenge of remyelination. Brain Sci 2013; 3:1282-324. [PMID: 24961530 PMCID: PMC4061877 DOI: 10.3390/brainsci3031282] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 08/12/2013] [Accepted: 08/12/2013] [Indexed: 12/26/2022] Open
Abstract
Multiple sclerosis (MS) is the most common demyelinating and an autoimmune disease of the central nervous system characterized by immune-mediated myelin and axonal damage, and chronic axonal loss attributable to the absence of myelin sheaths. T cell subsets (Th1, Th2, Th17, CD8+, NKT, CD4+CD25+ T regulatory cells) and B cells are involved in this disorder, thus new MS therapies seek damage prevention by resetting multiple components of the immune system. The currently approved therapies are immunoregulatory and reduce the number and rate of lesion formation but are only partially effective. This review summarizes current understanding of the processes at issue: myelination, demyelination and remyelination—with emphasis upon myelin composition/architecture and oligodendrocyte maturation and differentiation. The translational options target oligodendrocyte protection and myelin repair in animal models and assess their relevance in human. Remyelination may be enhanced by signals that promote myelin formation and repair. The crucial question of why remyelination fails is approached is several ways by examining the role in remyelination of available MS medications and avenues being actively pursued to promote remyelination including: (i) cytokine-based immune-intervention (targeting calpain inhibition), (ii) antigen-based immunomodulation (targeting glycolipid-reactive iNKT cells and sphingoid mediated inflammation) and (iii) recombinant monoclonal antibodies-induced remyelination.
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Wootla B, Watzlawik JO, Denic A, Rodriguez M. The road to remyelination in demyelinating diseases: current status and prospects for clinical treatment. Expert Rev Clin Immunol 2013; 9:535-49. [PMID: 23730884 DOI: 10.1586/eci.13.37] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Within CNS disorders, demyelinating diseases are among the most devastating and cost intensive due to long-term disabilities affecting relatively young patients. Multiple sclerosis, a chronic inflammatory demyelinating disease in which the persistent inhibitory microenvironment of the resident oligodendrocyte precursor cells abrogates regeneration of myelin sheaths, is the most prominent disease in the spectrum of demyelinating diseases. The essential goal is to stimulate creation of new myelin sheaths on the demyelinated axons, leading to restoration of saltatory conduction and resolving functional deficits. The past few decades witnessed significant efforts to understand the cellular interactions at the lesion site with studies suggesting efficient remyelination as a prerequisite for functional repair. Despite its proven efficacy in experimental models, immunosuppression has not had profound clinical consequences in multiple sclerosis, which argued for a paradigm shift in the design of therapeutics aiming to achieve remyelination. For example, targeting oligodendrocytes themselves may drive remyelination in the CNS. This group and others have demonstrated that natural autoreactive antibodies directed at oligodendrocyte progenitors participate in remyelination. Accordingly, the authors developed a recombinant autoreactive natural human IgM antibody with therapeutic potential for remyelination.
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Affiliation(s)
- Bharath Wootla
- Department of Neurology, Mayo Clinic, 200 1st Street SW, Rochester, MN 55905, USA.
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20
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Mecha M, Carrillo-Salinas FJ, Mestre L, Feliú A, Guaza C. Viral models of multiple sclerosis: neurodegeneration and demyelination in mice infected with Theiler's virus. Prog Neurobiol 2013; 101-102:46-64. [PMID: 23201558 PMCID: PMC7117056 DOI: 10.1016/j.pneurobio.2012.11.003] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 10/30/2012] [Accepted: 11/12/2012] [Indexed: 11/02/2022]
Abstract
Multiple sclerosis (MS) is a complex inflammatory disease of unknown etiology that affects the central nervous system (CNS) white matter, and for which no effective cure exists. Indeed, whether the primary event in MS pathology affects myelin or axons of the CNS remains unclear. Animal models are necessary to identify the immunopathological mechanisms involved in MS and to develop novel therapeutic and reparative approaches. Specifically, viral models of chronic demyelination and axonal damage have been used to study the contribution of viruses in human MS, and they have led to important breakthroughs in our understanding of MS pathology. The Theiler's murine encephalomyelitis virus (TMEV) model is one of the most commonly used MS models, although other viral models are also used, including neurotropic strains of mouse hepatitis virus (MHV) that induce chronic inflammatory demyelination with similar histological features to those observed in MS. This review will discuss the immunopathological mechanisms involved in TMEV-induced demyelinating disease (TMEV-IDD). The TMEV model reproduces a chronic progressive disease due to the persistence of the virus for the entire lifespan in susceptible mice. The evolution and significance of the axonal damage and neuroinflammation, the importance of epitope spread from viral to myelin epitopes, the presence of abortive remyelination and the existence of a brain pathology in addition to the classical spinal cord demyelination, are some of the findings that will be discussed in the context of this TMEV-IDD model. Despite their limitations, viral models remain an important tool to study the etiology of MS, and to understand the clinical and pathological variability associated with this disease.
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Key Words
- ab, antibody
- ag, antigen
- apc, antigen presenting cell
- bbb, blood–brain barrier
- cns, central nervous system
- cox-2, cyclooxygenase-2
- ctl, cytotoxic t lymphocytes
- dpi, days post-infection
- da, daniels strain of theiler's virus
- eae, experimental autoimmune encephalomyelitis
- galc, galactocerebroside
- mbp, myelin basic protein
- mnc, mononuclear cells
- mhc, major histocompatibility complex
- mhv, mouse hepatitis virus
- mog, myelin oligodendrocyte glycoprotein
- ms, multiple sclerosis
- naa, n-acetylaspartate
- no, nitric oxide
- pcr, polymerase chain reaction
- plp, myelin proteolipid protein
- pprs, pattern recognition receptors
- sfv, semliki forest virus
- sv, sindbis virus
- tmev, theiler's murine encephalomyelitis virus
- tmev-idd, theiler's murine encephalomyelitis virus-induced demyelinating disease
- tregs, regulatory t cells
- theiler's virus
- multiple sclerosis
- demyelination
- axonal damage
- neuroinflammation
- spinal cord pathology
- brain pathology
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Affiliation(s)
| | | | | | | | - Carmen Guaza
- Neuroimmunology Group, Functional and System Neurobiology Department, Instituto Cajal, Consejo Superior de Investigaciones Científicas, Avda Dr Arce 37, 28002 Madrid, Spain
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21
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Watzlawik JO, Warrington AE, Rodriguez M. PDGF is required for remyelination-promoting IgM stimulation of oligodendrocyte progenitor cell proliferation. PLoS One 2013; 8:e55149. [PMID: 23383310 PMCID: PMC3562326 DOI: 10.1371/journal.pone.0055149] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 12/27/2012] [Indexed: 12/13/2022] Open
Abstract
Background Promotion of remyelination is a major goal in treating demyelinating diseases such as multiple sclerosis (MS). The recombinant human monoclonal IgM, rHIgM22, targets myelin and oligodendrocytes (OLs) and promotes remyelination in animal models of MS. It is unclear whether rHIgM22-mediated stimulation of lesion repair is due to promotion of oligodendrocyte progenitor cell (OPC) proliferation and survival, OPC differentiation into myelinating OLs or protection of mature OLs. It is also unknown whether astrocytes or microglia play a functional role in IgM-mediated lesion repair. Methods We assessed the effect of rHIgM22 on cell proliferation in mixed CNS glial and OPC cultures by tritiated-thymidine uptake and by double-label immunocytochemistry using the proliferation marker, Ki-67. Antibody-mediated signaling events, OPC differentiation and OPC survival were investigated and quantified by Western blots. Results rHIgM22 stimulates OPC proliferation in mixed glial cultures but not in purified OPCs. There is no proliferative response in astrocytes or microglia. rHIgM22 activates PDGFαR in OPCs in mixed glial cultures. Blocking PDGFR-kinase inhibits rHIgM22-mediated OPC proliferation in mixed glia. We confirm in isolated OPCs that rHIgM22-mediated anti-apoptotic signaling and inhibition of OPC differentiation requires PDGF and FGF-2. We observed no IgM-mediated effect in mature OLs in the absence of PDGF and FGF-2. Conclusion Stimulation of OPC proliferation by rHIgM22 depends on co-stimulatory astrocytic and/or microglial factors. We demonstrate that rHIgM22-mediated activation of PDGFαR is required for stimulation of OPC proliferation. We propose that rHIgM22 lowers the PDGF threshold required for OPC proliferation and protection, which can result in remyelination of CNS lesions.
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Affiliation(s)
- Jens O. Watzlawik
- Departments of Neurology and Immunology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Arthur E. Warrington
- Departments of Neurology and Immunology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Moses Rodriguez
- Departments of Neurology and Immunology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
- * E-mail:
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22
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Warrington AE, Van Keulen V, Pease LR, Rodriguez M. Naturally occurring antibodies as therapeutics for neurologic disease: can human monoclonal IgMs replace the limited resource IVIG? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 750:44-55. [PMID: 22903665 DOI: 10.1007/978-1-4614-3461-0_4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Naturally occurring autoantibodies (NAbs) are common in normal humans. The majority of NAbs are IgMs, but a small proportion are IgGs. Therefore a certain portion of pooled whole human IgG (IVIG) can be considered NAbs. While the applications of IVIG to modulate human disease have increased dramatically, the use of IgMs as drugs has lagged. In fact, much of the contaminating IgM component of IVIG is disposed of as waste. However, a number of model studies, including those targeting Alzheimer and multiple sclerosis (MS) suggest that IgMs may better modulate disease at much lower doses than IVIG. Our own studies in a model of MS show that polyclonal human IgM promotes better remyelination than IVIG and that monoclonal IgMs promote greater remyelination than monoclonal IgGs containing identical variable region sequences. We propose that this difference is due to the ability of IgM to cross link cell surface antigens better than IgGs and induce signals in nervous system cells. Monoclonal antibodies (mAbs) that promote remyelination induce a transient Ca(2+) influx in myelin forming cells, whereas IgGs with identical variable sequences do not. MAbs that promote remyelination were identified in human serum and in EBV-immortalized human B-cell lines obtained from normal adults, fetal cord blood, and rheumatoid arthritis and MS patients. Therefore therapeutic mAbs are present and common in normal circulation. All therapeutic mAbs were IgMs and bound to nervous system cells, however, the tissue binding patterns suggest that binding any one of multiple antigens induces repair. An expression vector was constructed that can manufacture gram quantities of recombinant monoclonal human IgM. Therefore the technology exists to determine whether human monoclonal NAbs can modulate human disease. IVIG can modulate neurologic disease, but using IVIG to treat these chronic diseases is unsustainable. A long-term solution is to identify the functional component of IVIG and test whether a recombinant human monoclonal can replicate its efficacy.
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Affiliation(s)
- Arthur E Warrington
- Department of Neurology and Immunology, Mayo Clinic, Rochester, Minnesota, USA.
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23
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Mokhtarian F, Safavi F, Sarafraz-Yazdi E. Immunization with a peptide of Semliki Forest virus promotes remyelination in experimental autoimmune encephalomyelitis. Brain Res 2012; 1488:92-103. [PMID: 23031637 DOI: 10.1016/j.brainres.2012.09.038] [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: 06/18/2012] [Revised: 09/19/2012] [Accepted: 09/23/2012] [Indexed: 12/21/2022]
Abstract
Remyelination is one of the elusive topics in treatment of multiple sclerosis (MS). Our previous studies have shown that Semliki Forest virus (SFV)-infected δ-knock-out (KO) mice did not exhibit the extensive remyelination, seen in wild type (WT) B6 mice, after viral clearance and demyelination. The Remyelination in SFV-infected WT mice started on day 15 and was completed by day 35 post-infection (pi), whereas the KO mice remained partially demyelinated through day 42 pi. Treatment with E2 peptide2 in incomplete Freund's adjuvant (IFA), resulted in higher antibody production and earlier remyelination in SFV-infected KO (day 28 pi), than WT mice. This finding suggested that anti-E2 peptide2 antibody could play a part in remyelination. In the current study, the effect of E2 peptide2 treatment was evaluated in the experimental autoimmune encephalomyelitis (EAE) model. Mice with established EAE were treated with E2 peptide2 in IFA to develop antibody. Treated EAE mice made significantly higher anti-E2 peptide2 antibody than untreated EAE group. Average clinical disease scores were significantly lower in peptide treated compared to untreated EAE mice. Furthermore, histopathological and immunohistochemical studies demonstrated increased remyelinating areas and higher number of activated oligodendrocytes and astrocytes, in treated compared to untreated EAE groups. Moreover, the anti-E2 peptide2 antibody showed higher binding to the myelinated areas of treated than untreated EAE mice. We conclude that treatment with, or antibody to, SFV E2 peptide2 triggers some mechanism that promotes remyelination.
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MESH Headings
- Animals
- Antibodies, Viral/immunology
- Astrocytes/immunology
- Astrocytes/pathology
- Disease Models, Animal
- Encephalomyelitis, Autoimmune, Experimental/immunology
- Encephalomyelitis, Autoimmune, Experimental/pathology
- Encephalomyelitis, Autoimmune, Experimental/therapy
- Female
- Immunization
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Multiple Sclerosis/immunology
- Multiple Sclerosis/pathology
- Multiple Sclerosis/therapy
- Myelin Sheath/immunology
- Myelin Sheath/pathology
- Myelin-Oligodendrocyte Glycoprotein/immunology
- Nerve Regeneration/drug effects
- Nerve Regeneration/immunology
- Oligodendroglia/immunology
- Oligodendroglia/pathology
- Peptides/immunology
- Peptides/pharmacology
- Semliki forest virus/immunology
- Spinal Cord/immunology
- Spinal Cord/pathology
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Affiliation(s)
- Foroozan Mokhtarian
- Department of Cell Biology, SUNY Downstate, USA; Department of Neurology, SUNY Stony Brook, USA.
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24
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Wittenberg NJ, Im H, Xu X, Wootla B, Watzlawik J, Warrington AE, Rodriguez M, Oh SH. High-affinity binding of remyelinating natural autoantibodies to myelin-mimicking lipid bilayers revealed by nanohole surface plasmon resonance. Anal Chem 2012; 84:6031-9. [PMID: 22762372 PMCID: PMC3417152 DOI: 10.1021/ac300819a] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Multiple sclerosis is a progressive neurological disorder that results in the degradation of myelin sheaths that insulate axons in the central nervous system. Therefore promotion of myelin repair is a major thrust of multiple sclerosis treatment research. Two mouse monoclonal natural autoantibodies, O1 and O4, promote myelin repair in several mouse models of multiple sclerosis. Natural autoantibodies are generally polyreactive and predominantly of the IgM isotype. The prevailing paradigm is that because they are polyreactive, these antibodies bind antigens with low affinities. Despite their wide use in neuroscience and glial cell research, however, the affinities and kinetic constants of O1 and O4 antibodies have not been measured to date. In this work, we developed a membrane biosensing platform based on surface plasmon resonance in gold nanohole arrays with a series of surface modification techniques to form myelin-mimicking lipid bilayer membranes to measure both the association and dissociation rate constants for O1 and O4 antibodies binding to their myelin lipid antigens. The ratio of rate constants shows that O1 and O4 bind to galactocerebroside and sulfated galactocerebroside, respectively, with unusually small apparent dissociation constants (K(D) ≈ 0.9 nM) for natural autoantibodies. This is approximately one to 2 orders of magnitude lower than typically observed for the highest affinity natural autoantibodies. We propose that the unusually high affinity of O1 and O4 to their targets in myelin contributes to the mechanism by which they signal oligodendrocytes and induce central nervous system repair.
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Affiliation(s)
- Nathan J. Wittenberg
- Laboratory of Nanostructures and Biosensing, Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455 USA
| | - Hyungsoon Im
- Laboratory of Nanostructures and Biosensing, Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455 USA
| | - Xiaohua Xu
- Departments of Neurology, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
| | - Bharath Wootla
- Departments of Neurology, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
| | - Jens Watzlawik
- Departments of Neurology, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
- Immunology, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
| | - Arthur E. Warrington
- Departments of Neurology, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
| | - Moses Rodriguez
- Departments of Neurology, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
- Immunology, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
| | - Sang-Hyun Oh
- Laboratory of Nanostructures and Biosensing, Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455 USA
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25
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Nastasijevic B, Wright BR, Smestad J, Warrington AE, Rodriguez M, Maher LJ. Remyelination induced by a DNA aptamer in a mouse model of multiple sclerosis. PLoS One 2012; 7:e39595. [PMID: 22761835 PMCID: PMC3384608 DOI: 10.1371/journal.pone.0039595] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 05/28/2012] [Indexed: 11/18/2022] Open
Abstract
Multiple sclerosis (MS) is a debilitating inflammatory disease of the central nervous system (CNS) characterized by local destruction of the insulating myelin surrounding neuronal axons. With more than 200 million MS patients worldwide, the absence of treatments that prevent progression or induce repair poses a major challenge. Anti-inflammatory therapies have met with limited success only in preventing relapses. Previous screening of human serum samples revealed natural IgM antibodies that bind oligodendrocytes and promote both cell signaling and remyelination of CNS lesions in an MS model involving chronic infection of susceptible mice by Theiler's encephalomyelitis virus and in the lysolecithin model of focal demyelination. This intriguing result raises the possibility that molecules with binding specificity for oligodendrocytes or myelin components may promote therapeutic remyelination in MS. Because of the size and complexity of IgM antibodies, it is of interest to identify smaller myelin-specific molecules with the ability to promote remyelination in vivo. Here we show that a 40-nucleotide single-stranded DNA aptamer selected for affinity to murine myelin shows this property. This aptamer binds multiple myelin components in vitro. Peritoneal injection of this aptamer results in distribution to CNS tissues and promotes remyelination of CNS lesions in mice infected by Theiler's virus. Interestingly, the selected DNA aptamer contains guanosine-rich sequences predicted to induce folding involving guanosine quartet structures. Relative to monoclonal antibodies, DNA aptamers are small, stable, and non-immunogenic, suggesting new possibilities for MS treatment.
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Affiliation(s)
- Branislav Nastasijevic
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Brent R. Wright
- Departments of Neurology and Immunology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - John Smestad
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Arthur E. Warrington
- Departments of Neurology and Immunology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Moses Rodriguez
- Departments of Neurology and Immunology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
- * E-mail: (LJM); (MR)
| | - L. James Maher
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
- * E-mail: (LJM); (MR)
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26
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Smith GS, De Avila M, Paez PM, Spreuer V, Wills MK, Jones N, Boggs JM, Harauz G. Proline substitutions and threonine pseudophosphorylation of the SH3 ligand of 18.5-kDa myelin basic protein decrease its affinity for the Fyn-SH3 domain and alter process development and protein localization in oligodendrocytes. J Neurosci Res 2012; 90:28-47. [PMID: 21887699 PMCID: PMC3527418 DOI: 10.1002/jnr.22733] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Revised: 06/02/2011] [Accepted: 06/06/2011] [Indexed: 12/28/2022]
Abstract
The developmentally regulated myelin basic proteins (MBPs), which arise from the golli (gene of oligodendrocyte lineage) complex, are highly positively charged, intrinsically disordered, multifunctional proteins having several alternatively spliced isoforms and posttranslational modifications, and they play key roles in myelin compaction. The classic 18.5-kDa MBP isoform has a proline-rich region comprising amino acids 92-99 (murine sequence -T(92)PRTPPPS(99)-) that contains a minimal SH3 ligand domain. We have previously shown that 18.5-kDa MBP binds to several SH3 domains, including that of Fyn, a member of the Src family of tyrosine kinases involved in a number of signaling pathways during CNS development. To determine the physiological role of this binding as well as the role of phosphorylation of Thr92 and Thr95, in the current study we have produced several MBP variants specifically targeting phosphorylation sites and key structural regions of MBP's SH3 ligand domain. Using isothermal titration calorimetry, we have demonstrated that, compared with the wild-type protein, these variants have lower affinity for the SH3 domain of Fyn. Moreover, overexpression of N-terminal-tagged GFP versions in immortalized oligodendroglial N19 and N20.1 cell cultures results in aberrant elongation of membrane processes and increased branching complexity and inhibits the ability of MBP to decrease Ca(2+) influx. Phosphorylation of Thr92 can also cause MBP to traffic to the nucleus, where it may participate in additional protein-protein interactions. Coexpression of MBP with a constitutively active form of Fyn kinase resulted in membrane process elaboration, a phenomenon that was abolished by point amino acid substitutions in MBP's SH3 ligand domain. These results suggest that MBP's SH3 ligand domain plays a key role in intracellular protein interactions in vivo and may be required for proper membrane elaboration of developing oligodendrocytes and, further, that phosphorylation of Thr92 and Thr95 can regulate this function.
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Affiliation(s)
- Graham S.T. Smith
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Miguel De Avila
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Pablo M. Paez
- Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California
| | - Vilma Spreuer
- Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California
| | - Melanie K.B. Wills
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Nina Jones
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Joan M. Boggs
- Molecular Structure and Function, Hospital for Sick Children, and Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - George Harauz
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
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Evidence for the role of B cells and immunoglobulins in the pathogenesis of multiple sclerosis. Neurol Res Int 2011; 2011:780712. [PMID: 21961063 PMCID: PMC3179868 DOI: 10.1155/2011/780712] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Accepted: 07/27/2011] [Indexed: 01/06/2023] Open
Abstract
The pathogenesis of multiple sclerosis (MS) remains elusive. Recent reports advocate greater involvement of B cells and immunoglobulins in the initiation and propagation of MS lesions at different stages of their ontogeny. The key role of B cells and immunoglobulins in pathogenesis was initially identified by studies in which patients whose fulminant attacks of demyelination did not respond to steroids experienced remarkable functional improvement following plasma exchange. The positive response to Rituximab in Phase II clinical trials of relapsing-remitting MS confirms the role of B cells. The critical question is how B cells contribute to MS. In this paper, we discuss both the deleterious and the beneficial roles of B cells and immunoglobulins in MS lesions. We provide alternative hypotheses to explain both damaging and protective antibody responses.
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Xu X, Warrington AE, Wright BR, Bieber AJ, Van Keulen V, Pease LR, Rodriguez M. A human IgM signals axon outgrowth: coupling lipid raft to microtubules. J Neurochem 2011; 119:100-12. [PMID: 21824142 DOI: 10.1111/j.1471-4159.2011.07416.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Mouse and human IgMs support neurite extension from primary cerebellar granule neurons. In this study using primary hippocampal and cortical neurons, we demonstrate that a recombinant human IgM, rHIgM12, promotes axon outgrowth by coupling membrane domains (lipid rafts) to microtubules. rHIgM12 binds to the surface of neuron and induces clustering of cholesterol and ganglioside GM1. After cell binding and membrane fractionation, rHIgM12 gets segregated into two pools, one associated with lipid raft fractions and the other with the detergent-insoluble cytoskeleton-containing pellet. Membrane-bound rHIgM12 co-localized with microtubules and co-immuno precipitated with β3-tubulin. rHIgM12-membrane interaction also enhanced the tyrosination of α-tubulin indicating a stabilization of new neurites. When presented as a substrate, rHIgM12 induced axon outgrowth from primary neurons. We now demonstrate that a recombinant human mAb can induce signals in neurons that regulate membrane lipids and microtubule dynamics required for axon extension. We propose that the pentameric structure of the IgM is critical to cross-link membrane lipids and proteins resulting in signaling cascades.
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Affiliation(s)
- Xiaohua Xu
- Department of Neurology, Mayo Clinic and Foundation, Rochester, MN 55905, USA
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29
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Abstract
Demyelinating disorders of the central nervous system are among the most crippling neurological diseases affecting patients at various stages of life. In the most prominent demyelinating disease, multiple sclerosis, the regeneration of myelin sheaths often fails due to a default of the resident stem/precursor cells (oligodendrocyte precursor cells) to differentiate into mature myelin forming cells. Significant advances have been made in our understanding of the molecular and cellular processes involved in remyelination. Furthermore, important insight has been gained from studies investigating the interaction of stem/precursor cells with the distinct environment of demyelinating lesions. These suggest that successful regeneration depends on a signalling environment conducive to remyelination, which is provided in the context of acute inflammation. However, multiple sclerosis lesions also contain factors that inhibit the differentiation of oligodendrocyte precursor cells into myelinating oligodendrocytes. The pattern by which remyelination inducers and inhibitors are expressed in multiple sclerosis lesions may determine a window of opportunity during which oligodendrocyte precursor cells can successfully differentiate. As the first molecules aiming at promoting remyelination are about to enter clinical trials, this review critically evaluates recent advances in our understanding of the biology of oligodendrocyte precursor cells and of the stage-dependent molecular pathology of multiple sclerosis lesions relevant to the regeneration of myelin sheaths. We propose a model that may help to provide cues for how remyelination can be therapeutically enhanced in clinical disease.
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Affiliation(s)
- Mark R Kotter
- Department of Clinical Neurosciences, MRC Centre for Stem Cells and Regenerative Medicine, University of Cambridge, Addenbrooke's Hospital, Box 167, Hills Road, Cambridge CB22QQ, UK.
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Safavi F, Feliberti JP, Raine CS, Mokhtarian F. Role of γδ T cells in antibody production and recovery from SFV demyelinating disease. J Neuroimmunol 2011; 235:18-26. [PMID: 21612829 DOI: 10.1016/j.jneuroim.2011.02.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 02/03/2011] [Accepted: 02/28/2011] [Indexed: 01/03/2023]
Abstract
Semliki Forest Virus (SFV) encephalomyelitis has been used to study the pathogenesis of virus-induced demyelination and serves as a model for multiple sclerosis. SFV-infection of mice invariably leads to clinical weakness accompanied by CNS inflammation, viral clearance and primary demyelination by day 21 postinfection (pi), followed by recovery and remyelination by day 35 pi. We have applied this model to the examination of the effects of γδ T cells in antibody production and the pathogenesis of demyelinating lesions. SFV-infection of γδ T cell KO mice resulted in more severe clinical signs than in wild type (WT) B6 mice. SFV-infected WT and γδ KO mice both cleared virus by day 10 pi and inflammation was comparable. Demyelination also appeared to be similar in both groups except that KO mice did not exhibit extensive remyelination which was seen in WT mice by day 21. SFV-infected WT mice showed widespread remyelination by day 35 pi, whereas KO mice still displayed some demyelination through day 42 pi. Both WT and KO mice developed serum antibodies to SFV. However, the reactivity of WT sera with the SFV epitope, E2 T(h) peptide₂, was significantly higher than in KO sera. Immunization with E2 T(h) peptide₂ resulted in elevated antibody production to this peptide (p<0.05) and earlier remyelination (day 28 pi) in KO mice. Thus, our study has shown for the first time that immunization of SFV-infected γδ T cell KO mice with a viral peptide, E2 T(h) peptide₂ led to enhanced recovery and repair of the CNS.
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Affiliation(s)
- Farinaz Safavi
- Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, NY, USA
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31
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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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Smith GST, Paez PM, Spreuer V, Campagnoni CW, Boggs JM, Campagnoni AT, Harauz G. Classical 18.5-and 21.5-kDa isoforms of myelin basic protein inhibit calcium influx into oligodendroglial cells, in contrast to golli isoforms. J Neurosci Res 2011; 89:467-80. [PMID: 21312222 DOI: 10.1002/jnr.22570] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 11/02/2010] [Accepted: 11/04/2010] [Indexed: 11/10/2022]
Abstract
The myelin basic protein (MBP) family arises from different transcription start sites of the golli (gene of oligodendrocyte lineage) complex, with further variety generated by differential splicing. The "classical" MBP isoforms are peripheral membrane proteins that facilitate compaction of the mature myelin sheath but also have multiple protein interactions. The early developmental golli isoforms have previously been shown to promote process extension and enhance Ca(2+) influx into primary and immortalized oligodendrocyte cell lines. Here, we have performed similar studies with the classical 18.5- and 21.5-kDa isoforms of MBP. In contrast to golli proteins, overexpression of classical MBP isoforms significantly reduces Ca(2+) influx in the oligodendrocyte cell line N19 as well as in primary cultures of oligodendroglial progenitor cells. Pharmacological experiments demonstrate that this effect is mediated by voltage-operated Ca(2+) channels (VOCCs) and not by ligand-gated Ca(2+) channels or Ca(2+) release from intracellular stores. The pseudo-deiminated 18.5-kDa and the full-length 21.5-kDa isoforms do not reduce Ca(2+) influx as much as the unmodified 18.5-kDa isoform. However, more efficient membrane localization (of overexpressed, pseudo-deiminated 18.5-kDa and 21.5-kDa isoforms of classical MBP containing the 21-nt 3'-untranslated region transit signal) further reduces the Ca(2+) response after plasma membrane depolarization, suggesting that binding of classical MBP isoforms to the plasma membrane is important for modulation of Ca(2+) homeostasis. Furthermore, we have found that the mature 18.5-kDa isoform expressed in oligodendrocytes colocalizes with VOCCs, particularly at the leading edge of extending membrane processes. In summary, our findings suggest a key role for classical MBP proteins in regulating voltage-gated Ca(2+) channels at the plasma membrane of oligodendroglial cells and thus also in regulation of multiple developmental stages in this cell lineage.
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Affiliation(s)
- Graham S T Smith
- Department of Molecular and Cellular Biology, and Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario, Canada
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Abstract
INTRODUCTION Natural autoantibodies are part of the normal human immunoglobulin repertoire. These antibodies react to self-antigens, are usually polyreactive with relatively low affinity, and typically are of the IgM isotype. Natural IgMs in mice that stimulated remyelination in central nervous system (CNS) demyelinating disease all shared the characteristics of binding to the surface of live oligodendrocytes and myelinated tracts in living slices of CNS tissue. METHODS A screen for human IgMs with similar character resulted in two human natural antibodies, which when injected peripherally into animal models of demyelination induced remyelination. A recombinant human IgM (rHIgM22) that also promoted remyelination in vivo was constructed. RESULTS Very small doses of this IgM are required for the promotion of remyelination (EC50 is 460 ng per 20-g mouse). It is clear that after peripheral delivery, rHIgM22 enters the CNS and accumulates in CNS lesions. rHIgM22 was tracked in living mice using ferritin-labeled antihuman mu chain antibodies visualized by magnetic resonance imaging and traditional immunocytochemistry. Although the exact antigen recognized by rHIgM22 is not known, all mouse IgMs that promote remyelination bind to myelin membrane lipids, suggesting the antigen for rHIgM22 is similar. CONCLUSIONS We propose that the IgMs bind to CNS cells and reorganize the membrane, initiating a signal that results in oligodendrocyte proliferation and/or protection with an end result of increased myelin. Recombinant natural human antibodies are potentially important therapeutic molecules that may modulate a wide spectrum of human disease.
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Multiple kinase pathways regulate voltage-dependent Ca2+ influx and migration in oligodendrocyte precursor cells. J Neurosci 2010; 30:6422-33. [PMID: 20445068 DOI: 10.1523/jneurosci.5086-09.2010] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
It is becoming increasingly clear that voltage-operated Ca(2+) channels (VOCCs) play a fundamental role in the development of oligodendrocyte progenitor cells (OPCs). Because direct phosphorylation by different kinases is one of the most important mechanisms involved in VOCC modulation, the aim of this study was to evaluate the participation of serine-threonine kinases and tyrosine kinases (TKs) on Ca(2+) influx mediated by VOCCs in OPCs. Calcium imaging revealed that OPCs exhibited Ca(2+) influx after plasma membrane depolarization via L-type VOCCs. Furthermore, VOCC-mediated Ca(2+) influx declined with OPC differentiation, indicating that VOCCs are developmentally regulated in OPCs. PKC activation significantly increased VOCC activity in OPCs, whereas PKA activation produced the opposite effect. The results also indicated that OPC morphological changes induced by PKC activation were partially mediated by VOCCs. Our data clearly suggest that TKs exert an activating influence on VOCC function in OPCs. Furthermore, using the PDGF response as a model to probe the role of TK receptors (TKr) on OPC Ca(2+) uptake, we found that TKr activation potentiated Ca(2+) influx after membrane depolarization. Interestingly, this TKr modulation of VOCCs appeared to be essential for the PDGF enhancement of OPC migration rate, because cell motility was completely blocked by TKr antagonists, as well as VOCC inhibitors, in migration assays. The present study strongly demonstrates that PKC and TKrs enhance Ca(2+) influx induced by depolarization in OPCs, whereas PKA has an inhibitory effect. These kinases modulate voltage-operated Ca(2+) uptake in OPCs and participate in the modulation of process extension and migration.
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Luebke-Wheeler JL, Nedredal G, Yee L, Amiot BP, Nyberg SL. E-cadherin protects primary hepatocyte spheroids from cell death by a caspase-independent mechanism. Cell Transplant 2010; 18:1281-7. [PMID: 20003757 DOI: 10.3727/096368909x474258] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Cultivation of primary hepatocytes as spheroids creates an efficient three-dimensional model system for hepatic studies in vitro and as a cell source for a spheroid reservoir bioartificial liver. The mechanism of spheroid formation is poorly understood, as is an explanation for why normal, anchorage-dependent hepatocytes remain viable and do not undergo detachment-induced apoptosis, known as anoikis, when placed in suspension spheroid culture. The purpose of this study was to investigate the role of E-cadherin, a calcium-dependent cell adhesion molecule, in the formation and maintenance of hepatocyte spheroids. Hepatocyte spheroids were formed by a novel rocker technique and cultured in suspension for up to 24 h. The dependence of spheroid formation on E-cadherin and calcium was established using an E-cadherin blocking antibody and a calcium chelator. We found that inhibiting E-cadherin prevented cell-cell attachment and spheroid formation, and, surprisingly, E-cadherin inhibition led to hepatocyte death through a caspase-independent mechanism. In conclusion, E-cadherin is required for hepatocyte spheroid formation and may be responsible for protecting hepatocytes from a novel form of caspase-independent cell death.
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Watzlawik J, Warrington AE, Rodriguez M. Importance of oligodendrocyte protection, BBB breakdown and inflammation for remyelination. Expert Rev Neurother 2010; 10:441-57. [PMID: 20187865 DOI: 10.1586/ern.10.13] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the CNS. A better understanding of why remyelination fails in MS is necessary to improve remyelination strategies. Remyelination is mediated by oligodendrocyte precursor cells (OPCs), which are widely distributed throughout the adult CNS. However, it is still unclear whether OPCs detectable in MS lesions survive the inflammatory response but are unable to myelinate or whether OPC and oligodendrocyte death is primarily responsible for remyelination failure and detectable OPCs enter demyelinated areas from adjacent tissue as the lesion evolves. Remyelination strategies should, therefore, focus on stimulation of differentiation or prevention of apoptosis, as well as establishment of a supportive environment for OPC-mediated remyelination, which may be especially important in chronically demyelinated lesions.
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Affiliation(s)
- Jens Watzlawik
- Departments of Neurology and Immunology, Mayo Clinic College of Medicine, 200 First Street, SW, Rochester, MN 55905, USA
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Wright BR, Warrington AE, Edberg DD, Edberg DE, Rodriguez M. Cellular mechanisms of central nervous system repair by natural autoreactive monoclonal antibodies. ACTA ACUST UNITED AC 2010; 66:1456-9. [PMID: 20008649 DOI: 10.1001/archneurol.2009.262] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Natural autoreactive monoclonal IgM antibodies have demonstrated potential as therapeutic agents for central nervous system (CNS) disease. These antibodies bind surface antigens on specific CNS cells, activating intracellular repair-promoting signals. IgM antibodies that bind to surface antigens on oligodendrocytes enhanced remyelination in animal models of multiple sclerosis. IgM antibodies that bind to neurons stimulate neurite outgrowth and prevent neuron apoptosis. The neuron-binding IgM antibodies may have utility in CNS axon- or neuron-damaging diseases, such as amyotrophic lateral sclerosis, stroke, spinal cord injury, or secondary progressive multiple sclerosis. Recombinant remyelination-promoting IgM antibodies have been generated for formal toxicology studies and, after Food and Drug Administration approval, a phase 1 clinical trial. Natural autoreactive monoclonal antibodies directed against CNS cells represent novel therapeutic molecules to induce repair of the nervous system.
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Affiliation(s)
- Brent R Wright
- Department of Neurology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
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Podbielska M, Hogan EL. Molecular and immunogenic features of myelin lipids: incitants or modulators of multiple sclerosis? Mult Scler 2009; 15:1011-29. [PMID: 19692432 DOI: 10.1177/1352458509106708] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Myelin lipids have long been thought to play intriguing roles in the pathogenesis of multiple sclerosis (MS). This review summarizes current understanding of the molecular basis of MS with emphasis on the: (i.) physico-chemical properties, organization and accessibility of the lipids and their distribution within the myelin multilayer; (ii.) characterization of myelin lipid structures, and structure-function relationships relevant to MS mechanisms, and; (iii.) immunogenic and other features of lipids in MS including molecular mimicry, lipid enzyme genetic knockouts, glycolipid-reactive NKT cells, and monoclonal antibody-induced remyelination. New findings associate anti-lipid antibodies with pathophysiological biomarkers and suggest clinical utility. The structure of CD1d-lipid complexed with the lipophilic invariant T cell receptor (iTCR) may be crucial to understanding MS pathogenesis, and design of lipid antigen-specific therapeutics. Novel immuno-modulatory tools for treatment of autoimmune diseases including MS in which there is both constraint of inflammation and stimulation of remyelination are now emerging.
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Affiliation(s)
- M Podbielska
- Department of Neurology, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, Georgia, USA
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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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Rodriguez M, Warrington AE, Pease LR. Invited article: human natural autoantibodies in the treatment of neurologic disease. Neurology 2009; 72:1269-76. [PMID: 19349608 DOI: 10.1212/01.wnl.0000345662.05861.e4] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Naturally occurring autoantibodies are molecules that are part of the normal immunoglobulin repertoire. This review focuses on three distinct groups of human monoclonal antibodies (mAb). These are human natural autoantibodies that, when injected into an animal model of human disease, stimulate remyelination in CNS demyelinating diseases, protect neurons and extend neuronal processes in CNS axonal disorders, and activate immune dendritic cells to produce cytotoxic T cells to clear metastatic tumors. Natural autoantibodies react to self antigens and are of relatively low affinity. They are derived from germline immunoglobulin genes and are usually polyreactive. Our experiments demonstrated CNS entry by autoradiography of labeled mAb and by MRI. Remyelinating mAb rHIgM22 clusters beta-integrin and mouse mAb O4 recognizes sulfatide. Neuronal outgrowth mAbs sHIgM42 and sHIgM12 appear to target carbohydrates on the surface of neurons. The mAb sHIgM12 (B7-DC-Xab) also is promising as therapeutic against metastatic tumors. It functions by binding and cross-linking the antigen B7-DC on dendritic cells, inducing tumor-specific cytotoxic T cells. All these mAbs activate a transient increase in intracellular calcium, signal via NFkappab, and prevent apoptosis. The mAbs engage downstream signaling events that induce the primary function of the cell (that is, remyelination for oligodendrocytes, axonal preservation and neurite extension for neurons, or antigen presentation for dendritic cells). Natural human auto mAbs are a potentially important therapeutic technique in combating a wide spectrum of disease processes.
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Affiliation(s)
- Moses Rodriguez
- Department of Immunology and Neurology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
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42
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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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Abstract
Remyelination involves reinvesting demyelinated axons with new myelin sheaths. In stark contrast to the situation that follows loss of neurons or axonal damage, remyelination in the CNS can be a highly effective regenerative process. It is mediated by a population of precursor cells called oligodendrocyte precursor cells (OPCs), which are widely distributed throughout the adult CNS. However, despite its efficiency in experimental models and in some clinical diseases, remyelination is often inadequate in demyelinating diseases such as multiple sclerosis (MS), the most common demyelinating disease and a cause of neurological disability in young adults. The failure of remyelination has profound consequences for the health of axons, the progressive and irreversible loss of which accounts for the progressive nature of these diseases. The mechanisms of remyelination therefore provide critical clues for regeneration biologists that help them to determine why remyelination fails in MS and in other demyelinating diseases and how it might be enhanced therapeutically.
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Abstract
Neurodegeneration develops in association with inflammation and demyelination in multiple sclerosis. Available data suggest that the progressive neuroaxonal loss begins in the earliest stages of the disease and underlies the accumulation of clinical disability. The loss of neurons and their processes is driven by a complex molecular mechanism involving cellular and humoral immune histotoxicity, demyelination, reduced neurotrophic support, metabolic impairment, and altered intracellular processes. Here we survey available data concerning the role of autoreactive immunoglobulins in neurotoxicity. A better understanding of molecular pathways leading to immune-mediated neurodegeneration may have key importance in the successful treatment of the disease.
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Remyelination-promoting human IgMs: developing a therapeutic reagent for demyelinating disease. Curr Top Microbiol Immunol 2008; 318:213-39. [PMID: 18219820 PMCID: PMC7120407 DOI: 10.1007/978-3-540-73677-6_9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Promoting remyelination following injury to the central nervous system (CNS) promises to be an effective neuroprotective strategy to limit the loss of surviving axons and prevent disability. Studies confirm that multiple sclerosis (MS) and spinal cord injury lesions contain myelinating cells and their progenitors. Recruiting these endogenous cells to remyelinate may be of therapeutic value. This review addresses the use of antibodies reactive to CNS antigens to promote remyelination. Antibody-induced remyelination in a virus-mediated model of chronic spinal cord injury was initially observed in response to treatment with CNS reactive antisera. Monoclonal mouse and human IgMs, which bind to the surface of oligodendrocytes and myelin, were later identified that were functionally equivalent to antisera. A recombinant form of a human remyelination-promoting IgM (rHIgM22) targets areas of CNS injury and promotes maximal remyelination within 5 weeks after a single low dose (25 microg/kg). The IgM isoform of this reparative antibody is required for in vivo function. We hypothesize that the IgM clusters membrane domains and associated signaling molecules on the surface of target cells. Current therapies for MS are designed to modulate inflammation. In contrast, remyelination promoting IgMs are the first potential therapeutic molecules designed to induce tissue repair by acting within the CNS at sites of damage on the cells responsible for myelin synthesis.
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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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Warrington AE, Bieber AJ, Ciric B, Pease LR, Van Keulen V, Rodriguez M. A recombinant human IgM promotes myelin repair after a single, very low dose. J Neurosci Res 2007; 85:967-76. [PMID: 17304578 DOI: 10.1002/jnr.21217] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A recombinant human monoclonal IgM, rHIgM22, promotes the synthesis of new myelin when used to treat several animal models of demyelination. rHIgM22 binds to myelin and the surface of oligodendrocytes and accumulates at central nervous system lesions in vivo. The minimal dose of monoclonal IgM required to promote remyelination has a direct bearing on the proposed mechanism of action. A dose ranging study using rHIgM22 was performed in mice with chronic virus-induced demyelination, a model of chronic progressive multiple sclerosis. The lowest tested dose of rHIgM22 effective at promoting spinal cord remyelination was a single 500-ng intraperitoneal bolus injection. A time course study of spinal cord repair performed in chronically demyelinated mice revealed that remyelination plateaued by 5 weeks following treatment with rHIgM22. Two doses of rHIgM22 spaced 5 weeks apart did not increase the extent of remyelination over a single dose. The half-life of rHIgM22 in the mouse systemic circulation was determined to be 15 hr; the human IgM serum concentration was close to zero by 48 hr following antibody administration. We propose that the specificity of rHIgM22 for myelin on living tissue targets the antibody to demyelinated lesions, initiating a long-term reparative effect on the central nervous system.
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Affiliation(s)
- Arthur E Warrington
- Department of Neurology, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA.
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Musse AA, Harauz G. Molecular "negativity" may underlie multiple sclerosis: role of the myelin basic protein family in the pathogenesis of MS. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2007; 79:149-72. [PMID: 17531841 DOI: 10.1016/s0074-7742(07)79007-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Myelin basic protein (MBP) binds to negatively charged lipids on the cytosolic surface of oligodendrocyte membranes and is responsible for adhesion of these surfaces in the multilayered myelin sheath. The pattern of extensive posttranslational modifications of MBP is dynamic during normal central nervous system development and during myelin degeneration in multiple sclerosis (MS), affecting its interactions with the myelin membranes and other proteins. In particular, the degree of deimination (or citrullination) of MBP is correlated with the severity of MS, and may represent a primary defect that precedes neurodegeneration due to autoimmune attack. That MBP deimination also affects topological accessibility of an otherwise partially buried immunodominant epitope of the protein indicates that this modification may play a major role in the autoimmune pathogenesis of the disease. In this chapter, we describe the structural and functional consequences of MBP deimination in healthy and diseased myelin.
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Affiliation(s)
- Abdiwahab A Musse
- Department of Molecular and Cellular Biology, Biophysics Interdepartmental Group, University of Guelph, Ontario N1G 2W1, Canada
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Abstract
The function of oligodendrocytes is to myelinate CNS axons. Oligodendrocytes and the axons they myelinate are functional units, and neurotransmitters released by axons can influence all stages of oligodendrocyte development via calcium dependent mechanisms. Some of the clearest functional evidence is for adenosine, ATP, and glutamate, which are released by electrically active axons and regulate the migration and proliferation of oligodendrocyte progenitor cells and their differentiation into myelinating oligodendrocytes. Glutamate and ATP, released by both axons and astrocytes, continue to mediate Ca(2+) signaling in mature oligodendrocytes, acting via AMPA and NMDA glutamate receptors, and heterogeneous P2X and P2Y purinoceptors. Physiological signalling between axons, astrocytes, and oligodendrocytes is likely to play an important role in myelin maintenance throughout life. Significantly, ATP- and glutamate-mediated Ca(2+) signaling are also major components of oligodendrocyte and myelin damage in numerous pathologies, most notably ischemia, injury, periventricular leukomalacia, and multiple sclerosis. In addition, NG2-expressing glia (synantocytes) in the adult CNS are highly reactive cells that respond rapidly to any CNS insult by a characteristic gliosis, and are able to regenerate oligodendrocytes and possibly neurons. Glutamate and ATP released by neurons and astrocytes evoke Ca(2+) signaling in NG2-glia (synantocytes), and it is proposed these regulate their differentiation capacity and response to injury. In summary, clear roles have been demonstrated for neurotransmitter-mediated Ca(2+) signaling in oligodendrocyte development and pathology. A key issue for future studies is to determine the physiological roles of neurotransmitters in mature oligodendrocytes and NG2-glia (synantocytes).
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Affiliation(s)
- Arthur M Butt
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, United Kingdom
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Jacobs EC, Pribyl TM, Feng JM, Kampf K, Spreur V, Campagnoni C, Colwell CS, Reyes SD, Martin M, Handley V, Hiltner TD, Readhead C, Jacobs RE, Messing A, Fisher RS, Campagnoni AT. Region-specific myelin pathology in mice lacking the golli products of the myelin basic protein gene. J Neurosci 2005; 25:7004-13. [PMID: 16049176 PMCID: PMC6724835 DOI: 10.1523/jneurosci.0288-05.2005] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2005] [Revised: 06/07/2005] [Accepted: 06/09/2005] [Indexed: 01/07/2023] 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. In this study, targeted ablation of the golli-MBPs, but not the classic MBPs, resulted in a distinct phenotype unlike that of knock-outs (KOs) of the classic MBPs or other myelin proteins. Although the golli KO animals did not display an overt dysmyelinating phenotype, they did exhibit delayed and/or hypomyelination in selected areas of the brain, such as the visual cortex and the optic nerve, as determined by Northern and Western blots and immunohistochemical analysis with myelin protein markers. Hypomyelination in some areas, such as the visual cortex, persisted into adulthood. Ultrastructural analysis of the KOs confirmed both the delay and hypomyelination and revealed abnormalities in myelin structure and in some oligodendrocytes. Abnormal visual-evoked potentials indicated that the hypomyelination in the visual cortex had functional consequences in the golli KO brain. Evidence that the abnormal myelination in these animals was a consequence of intrinsic problems with the oligodendrocyte was indicated by an impaired ability of oligodendrocytes to form myelin sheets in culture and by the presence of abnormal Ca2+ transients in purified cortical oligodendrocytes studied in vitro. The Ca2+ results reported in this study complement previous results implicating golli proteins in modulating intracellular signaling in T-cells. Together, all these findings suggest a role for golli proteins in oligodendrocyte differentiation, migration, and/or myelin elaboration in the brain.
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Affiliation(s)
- Erin C Jacobs
- Neuropsychiatric Institute, University of California Los Angeles School of Medicine, Los Angeles, California 90024, USA
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