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Contreras C, Cádiz B, Schmachtenberg O. Determination of the Severity of Pulpitis by Immunohistological Analysis and Comparison with the Clinical Picture. J Endod 2022; 49:26-35. [DOI: 10.1016/j.joen.2022.10.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 09/23/2022] [Accepted: 10/31/2022] [Indexed: 11/09/2022]
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Reed CB, Feltri ML, Wilson ER. Peripheral glia diversity. J Anat 2022; 241:1219-1234. [PMID: 34131911 PMCID: PMC8671569 DOI: 10.1111/joa.13484] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 05/20/2021] [Accepted: 05/26/2021] [Indexed: 12/13/2022] Open
Abstract
Recent years have seen an evolving appreciation for the role of glial cells in the nervous system. As we move away from the typical neurocentric view of neuroscience, the complexity and variability of central nervous system glia is emerging, far beyond the three main subtypes: astrocytes, oligodendrocytes, and microglia. Yet the diversity of the glia found in the peripheral nervous system remains rarely discussed. In this review, we discuss the developmental origin, morphology, and function of the different populations of glia found in the peripheral nervous system, including: myelinating Schwann cells, Remak Schwann cells, repair Schwann cells, satellite glia, boundary cap-derived glia, perineurial glia, terminal Schwann cells, glia found in the skin, olfactory ensheathing cells, and enteric glia. The morphological and functional heterogeneity of glia found in the periphery reflects the diverse roles the nervous system performs throughout the body. Further, it highlights a complexity that should be appreciated and considered when it comes to a complete understanding of the peripheral nervous system in health and disease.
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Affiliation(s)
- Chelsey B Reed
- Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences State, University of New York at Buffalo, Buffalo, New York, USA
- Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - M Laura Feltri
- Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences State, University of New York at Buffalo, Buffalo, New York, USA
- Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Emma R Wilson
- Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences State, University of New York at Buffalo, Buffalo, New York, USA
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
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3
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Ostertag C, Klein D, Martini R. Presymptomatic macrophage targeting has a long-lasting therapeutic effect on treatment termination. Exp Neurol 2022; 357:114195. [PMID: 35931123 DOI: 10.1016/j.expneurol.2022.114195] [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: 04/29/2022] [Revised: 07/11/2022] [Accepted: 07/31/2022] [Indexed: 11/24/2022]
Abstract
Macrophage-mediated inflammation is a potent driver of disease progression in mouse models of Charcot-Marie-Tooth (CMT) 1 diseases. This leads to the possibility to consider these cells as therapeutic targets to dampen disease outcome in the so far non-treatable neuropathies. As a pharmacological proof-of-principle study, long-term targeting of nerve macrophages with the orally applied CSF-1 receptor specific kinase (c-FMS) inhibitor PLX5622 showed a substantial alleviation of the neuropathy in distinct CMT1 mouse models. However, regarding translational options, clinically relevant questions emerged regarding treatment onset, duration and termination. Corroborating previous data, we here show that in a model for CMT1B, peripheral neuropathy was substantially alleviated after early continuous PLX5622 treatment in CMT1B mice, leading to preserved motor function. However, late-onset treatment failed to mitigate histopathological and clinical features, despite a similar reduction in the number of macrophages. Surprisingly, in CMT1B mice, terminating early PLX5622 treatment at six months was still sufficient to preserve motor function at 12 months of age, suggesting a long-lasting, therapeutic effect of early macrophage depletion. This novel and unexpected finding may have important translational implications, since we here show that continuous macrophage targeting appears not to be necessary for disease alleviation, provided that the treatment starts within an early, critical time window.
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Affiliation(s)
- Charlotte Ostertag
- Department of Neurology, Developmental Neurobiology, University Hospital Würzburg, Würzburg, Germany
| | - Dennis Klein
- Department of Neurology, Developmental Neurobiology, University Hospital Würzburg, Würzburg, Germany.
| | - Rudolf Martini
- Department of Neurology, Developmental Neurobiology, University Hospital Würzburg, Würzburg, Germany.
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4
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Abstract
Demyelinating forms of Charcot-Marie-Tooth disease (CMT) are genetically and phenotypically heterogeneous and result from highly diverse biological mechanisms including gain of function (including dominant negative effects) and loss of function. While no definitive treatment is currently available, rapid advances in defining the pathomechanisms of demyelinating CMT have led to promising pre-clinical studies, as well as emerging clinical trials. Especially promising are the recently completed pre-clinical genetic therapy studies in PMP-22, GJB1, and SH3TC2-associated neuropathies, particularly given the success of similar approaches in humans with spinal muscular atrophy and transthyretin familial polyneuropathy. This article focuses on neuropathies related to mutations in PMP-22, MPZ, and GJB1, which together comprise the most common forms of demyelinating CMT, as well as on select rarer forms for which promising treatment targets have been identified. Clinical characteristics and pathomechanisms are reviewed in detail, with emphasis on therapeutically targetable biological pathways. Also discussed are the challenges facing the CMT research community in its efforts to advance the rapidly evolving biological insights to effective clinical trials. These considerations include the limitations of currently available animal models, the need for personalized medicine approaches/allele-specific interventions for select forms of demyelinating CMT, and the increasing demand for optimal clinical outcome assessments and objective biomarkers.
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Affiliation(s)
- Vera Fridman
- Department of Neurology, University of Colorado Anschutz Medical Campus, 12631 E 17th Avenue, Mailstop B185, Room 5113C, Aurora, CO, 80045, USA.
| | - Mario A Saporta
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
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5
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Stassart RM, Woodhoo A. Axo-glial interaction in the injured PNS. Dev Neurobiol 2020; 81:490-506. [PMID: 32628805 DOI: 10.1002/dneu.22771] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/28/2020] [Accepted: 06/12/2020] [Indexed: 12/11/2022]
Abstract
Axons share a close relationship with Schwann cells, their glial partners in peripheral nerves. An intricate axo-glia network of signals and bioactive molecules regulates the major aspects of nerve development and normal functioning of the peripheral nervous system. Disruptions to these complex axo-glial interactions can have serious neurological consequences, as typically seen in injured nerves. Recent studies in inherited neuropathies have demonstrated that damage to one of the partners in this symbiotic unit ultimately leads to impairment of the other partner, emphasizing the bidirectional influence of axon to glia and glia to axon signaling in these diseases. After physical trauma to nerves, dramatic alterations in the architecture and signaling environment of peripheral nerves take place. Here, axons and Schwann cells respond adaptively to these perturbations and change the nature of their reciprocal interactions, thereby driving the remodeling and regeneration of peripheral nerves. In this review, we focus on the nature and importance of axon-glia interactions in injured nerves, both for the reshaping and repair of nerves after trauma, and in driving pathology in inherited peripheral neuropathies.
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Affiliation(s)
- Ruth M Stassart
- Department of Neuropathology, University Clinic Leipzig, Leipzig, Germany
| | - Ashwin Woodhoo
- Nerve Disorders Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia, Spain.,IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
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6
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Sahley TL, Anderson DJ, Hammonds MD, Chandu K, Musiek FE. Evidence for a dynorphin-mediated inner ear immune/inflammatory response and glutamate-induced neural excitotoxicity: an updated analysis. J Neurophysiol 2019; 122:1421-1460. [DOI: 10.1152/jn.00595.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Acoustic overstimulation (AOS) is defined as the stressful overexposure to high-intensity sounds. AOS is a precipitating factor that leads to a glutamate (GLU)-induced Type I auditory neural excitotoxicity and an activation of an immune/inflammatory/oxidative stress response within the inner ear, often resulting in cochlear hearing loss. The dendrites of the Type I auditory neural neurons that innervate the inner hair cells (IHCs), and respond to the IHC release of the excitatory neurotransmitter GLU, are themselves directly innervated by the dynorphin (DYN)-bearing axon terminals of the descending brain stem lateral olivocochlear (LOC) system. DYNs are known to increase GLU availability, potentiate GLU excitotoxicity, and induce superoxide production. DYNs also increase the production of proinflammatory cytokines by modulating immune/inflammatory signal transduction pathways. Evidence is provided supporting the possibility that the GLU-mediated Type I auditory neural dendritic swelling, inflammation, excitotoxicity, and cochlear hearing loss that follow AOS may be part of a brain stem-activated, DYN-mediated cascade of inflammatory events subsequent to a LOC release of DYNs into the cochlea. In support of a DYN-mediated cascade of events are established investigations linking DYNs to the immune/inflammatory/excitotoxic response in other neural systems.
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Affiliation(s)
- Tony L. Sahley
- Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, Ohio
- School of Health Sciences, Cleveland State University, Cleveland, Ohio
| | - David J. Anderson
- Department of Chemistry, Cleveland State University, Cleveland, Ohio
| | | | - Karthik Chandu
- Department of Chemistry, Cleveland State University, Cleveland, Ohio
| | - Frank E. Musiek
- Department of Speech, Language, and Hearing Sciences, University of Arizona, Tucson, Arizona
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Mindos T, Dun XP, North K, Doddrell RDS, Schulz A, Edwards P, Russell J, Gray B, Roberts SL, Shivane A, Mortimer G, Pirie M, Zhang N, Pan D, Morrison H, Parkinson DB. Merlin controls the repair capacity of Schwann cells after injury by regulating Hippo/YAP activity. J Cell Biol 2017; 216:495-510. [PMID: 28137778 PMCID: PMC5294779 DOI: 10.1083/jcb.201606052] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 10/23/2016] [Accepted: 12/27/2016] [Indexed: 02/06/2023] Open
Abstract
Loss of the Merlin tumor suppressor and activation of the Hippo signaling pathway play major roles in the control of cell proliferation and tumorigenesis. We have identified completely novel roles for Merlin and the Hippo pathway effector Yes-associated protein (YAP) in the control of Schwann cell (SC) plasticity and peripheral nerve repair after injury. Injury to the peripheral nervous system (PNS) causes a dramatic shift in SC molecular phenotype and the generation of repair-competent SCs, which direct functional repair. We find that loss of Merlin in these cells causes a catastrophic failure of axonal regeneration and remyelination in the PNS. This effect is mediated by activation of YAP expression in Merlin-null SCs, and loss of YAP restores axonal regrowth and functional repair. This work identifies new mechanisms that control the regenerative potential of SCs and gives new insight into understanding the correct control of functional nerve repair in the PNS.
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Affiliation(s)
- Thomas Mindos
- Plymouth University Peninsula Schools of Medicine and Dentistry, Plymouth PL6 8BU, England, UK
| | - Xin-Peng Dun
- Plymouth University Peninsula Schools of Medicine and Dentistry, Plymouth PL6 8BU, England, UK
| | - Katherine North
- Plymouth University Peninsula Schools of Medicine and Dentistry, Plymouth PL6 8BU, England, UK
- University of Bath, Bath BA2 7AY, England, UK
| | - Robin D S Doddrell
- Plymouth University Peninsula Schools of Medicine and Dentistry, Plymouth PL6 8BU, England, UK
| | - Alexander Schulz
- Leibniz Institute for Age Research - Fritz Lipmann Institute Jena, D-07745 Jena, Germany
| | - Philip Edwards
- Department of Cellular and Anatomical Pathology, Derriford Hospital, Plymouth PL6 8DH, England, UK
| | - James Russell
- Plymouth University Peninsula Schools of Medicine and Dentistry, Plymouth PL6 8BU, England, UK
| | - Bethany Gray
- Plymouth University Peninsula Schools of Medicine and Dentistry, Plymouth PL6 8BU, England, UK
- University of Bath, Bath BA2 7AY, England, UK
| | - Sheridan L Roberts
- Plymouth University Peninsula Schools of Medicine and Dentistry, Plymouth PL6 8BU, England, UK
| | - Aditya Shivane
- Department of Cellular and Anatomical Pathology, Derriford Hospital, Plymouth PL6 8DH, England, UK
| | - Georgina Mortimer
- Plymouth University Peninsula Schools of Medicine and Dentistry, Plymouth PL6 8BU, England, UK
| | - Melissa Pirie
- Plymouth University Peninsula Schools of Medicine and Dentistry, Plymouth PL6 8BU, England, UK
| | - Nailing Zhang
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Duojia Pan
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Helen Morrison
- Leibniz Institute for Age Research - Fritz Lipmann Institute Jena, D-07745 Jena, Germany
| | - David B Parkinson
- Plymouth University Peninsula Schools of Medicine and Dentistry, Plymouth PL6 8BU, England, UK
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8
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Martini R, Willison H. Neuroinflammation in the peripheral nerve: Cause, modulator, or bystander in peripheral neuropathies? Glia 2016; 64:475-86. [PMID: 26250643 PMCID: PMC4832258 DOI: 10.1002/glia.22899] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 07/21/2015] [Accepted: 07/22/2015] [Indexed: 12/15/2022]
Abstract
The role of innate and adaptive inflammation as a primary driver or modifier of neuropathy in premorbidly normal nerves, and as a critical player in amplifying neuropathies of other known causes (e.g., genetic, metabolic) is incompletely understood and under-researched, despite unmet clinical need. Also, cellular and humoral components of the adaptive and innate immune system are substantial disease modifying agents in the context of neuropathies and, at least in some neuropathies, there is an identified tight interrelationship between both compartments of the immune system. Additionally, the quadruple relationship between Schwann cell, axon, macrophage, and endoneurial fibroblast, with their diverse membrane bound and soluble signalling systems, forms a distinct focus for investigation in nerve diseases with inflammation secondary to Schwann cell mutations and possibly others. Identification of key immunological effector pathways that amplify neuropathic features and associated clinical symptomatology including pain should lead to realistic and timely possibilities for translatable therapeutic interventions using existing immunomodulators, alongside the development of novel therapeutic targets.
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Affiliation(s)
- Rudolf Martini
- Department of NeurologyDevelopmental Neurobiology, University Hospital WürzburgWürzburgD‐97080Germany
| | - Hugh Willison
- Institute of Infection, Immunity and Inflammation College of Medical Veterinary and Life Sciences, Glasgow Biomedical Research Centre, University of GlasgowGlasgowG12 8TA
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9
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Klein D, Martini R. Myelin and macrophages in the PNS: An intimate relationship in trauma and disease. Brain Res 2015; 1641:130-138. [PMID: 26631844 DOI: 10.1016/j.brainres.2015.11.033] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 11/18/2015] [Accepted: 11/19/2015] [Indexed: 01/08/2023]
Abstract
Macrophages of the peripheral nervous system belong to the so-called tissue macrophages, with multiple functions during injury and disease. Their origin during ontogeny has not yet been completely resolved, but it is clear that upon injury and disease conditions, they are supplemented by hematopoietic derivatives. In the peripheral nervous system, the most abundantly investigated scenario in which resident and infiltrating macrophages are involved is the so-called "Wallerian degeneration", a complex degenerative process where macrophages exhibit mostly beneficial functions by phagocytosing myelin and axonal remnants. Of special interest is the implication of macrophages in inflammatory nerve diseases, like acute Guillain-Barré syndromes and its permanent variant, chronic inflammatory demyelinating polyneuropathy, where macrophages are supposed to be substantial (co-)mediators of the diseases. In inherited peripheral neuropathies nerve macrophages possess a clear disease-amplifying function. In the corresponding animal models, a coordinated interplay between mutant Schwann cells, macrophages, endoneurial fibroblasts and the target structure, myelin, emerged. Along this process, a newly discovered disease mechanism mediated by macrophages is the dedifferentiation of myelinating Schwann cells. As macrophages are amplifiers of the genetically-mediated, non-curable diseases, targeting the mechanisms of their activation might be a promising strategy to treat these disorders. This article is part of a Special Issue entitled SI: Myelin Evolution.
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Affiliation(s)
- Dennis Klein
- University Hospital Würzburg, Department of Neurology, Developmental Neurobiology, Josef-Schneider Str. 11, 97080 Würzburg, Germany
| | - Rudolf Martini
- University Hospital Würzburg, Department of Neurology, Developmental Neurobiology, Josef-Schneider Str. 11, 97080 Würzburg, Germany.
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10
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Patzig J, Kusch K, Fledrich R, Eichel MA, Lüders KA, Möbius W, Sereda MW, Nave KA, Martini R, Werner HB. Proteolipid protein modulates preservation of peripheral axons and premature death when myelin protein zero is lacking. Glia 2015; 64:155-74. [PMID: 26393339 DOI: 10.1002/glia.22922] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 09/04/2015] [Indexed: 12/23/2022]
Abstract
Protein zero (P0) is the major structural component of peripheral myelin. Lack of this adhesion protein from Schwann cells causes a severe dysmyelinating neuropathy with secondary axonal degeneration in humans with the neuropathy Dejerine-Sottas syndrome (DSS) and in the corresponding mouse model (P0(null)-mice). In the mammalian CNS, the tetraspan-membrane protein PLP is the major structural myelin constituent and required for the long-term preservation of myelinated axons, which fails in hereditary spastic paraplegia (SPG type-2) and the relevant mouse model (Plp(null)-mice). The Plp-gene is also expressed in Schwann cells but PLP is of very low abundance in normal peripheral myelin; its function has thus remained enigmatic. Here we show that the abundance of PLP but not of other tetraspan myelin proteins is strongly increased in compact peripheral myelin of P0(null)-mice. To determine the functional relevance of PLP expression in the absence of P0, we generated P0(null)*Plp(null)-double-mutant mice. Compared with either single-mutant, P0(null)*Plp(null)-mice display impaired nerve conduction, reduced motor functions, and premature death. At the morphological level, axonal segments were frequently non-myelinated but in a one-to-one relationship with a hypertrophic Schwann cell. Importantly, axonal numbers were reduced in the vital phrenic nerve of P0(null)*Plp(null)-mice. In the absence of P0, thus, PLP also contributes to myelination by Schwann cells and to the preservation of peripheral axons. These data provide a link between the Schwann cell-dependent support of peripheral axons and the oligodendrocyte-dependent support of central axons.
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Affiliation(s)
- Julia Patzig
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Kathrin Kusch
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Robert Fledrich
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Maria A Eichel
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Katja A Lüders
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Göttingen, Germany
| | - Michael W Sereda
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Department of Clinical Neurophysiology, University Medical Center, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Rudolf Martini
- Department of Neurology, Developmental Neurobiology, University Hospital, Würzburg, Germany
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
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Tzekova N, Heinen A, Bunk S, Hermann C, Hartung HP, Reipert B, Küry P. Immunoglobulins stimulate cultured Schwann cell maturation and promote their potential to induce axonal outgrowth. J Neuroinflammation 2015; 12:107. [PMID: 26022648 PMCID: PMC4450464 DOI: 10.1186/s12974-015-0331-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 05/20/2015] [Indexed: 02/06/2023] Open
Abstract
Background Schwann cells are the myelinating glial cells of the peripheral nervous system and exert important regenerative functions revealing them as central repair components of many peripheral nerve pathologies. Intravenous immunoglobulins (IVIG) are widely used to treat autoimmune and inflammatory diseases including immune-mediated neuropathies. Nevertheless, promotion of peripheral nerve regeneration is currently an unmet therapeutical goal. We therefore examined whether immunoglobulins affect glial cell homeostasis, differentiation, and Schwann cell dependent nerve regenerative processes. Methods The responses of different primary Schwann cell culture models to IVIG were investigated: immature or differentiation competent Schwann cells, myelinating neuron/glial cocultures, and dorsal root ganglion explants. Immature or differentiating Schwann cells were used to study cellular proliferation, morphology, and gene/protein expression. Myelination rates were determined using myelinating neuron/glia cocultures, whereas axonal outgrowth was assessed using non-myelinating dorsal root ganglion explants. Results We found that IVIG specifically bind to Schwann cells and detected CD64 Fc receptor expression on their surface. In response to IVIG binding, Schwann cells reduced proliferation rates and accelerated growth of cellular protrusions. Furthermore, we observed that IVIG treatment transiently boosts myelin gene expression and myelination-related signaling pathways of immature cells, whereas in differentiating Schwann cells, myelin expression is enhanced on a long-term scale. Importantly, myelin gene upregulation was not detected upon application of IgG1 control antibodies. In addition, we demonstrate for the first time that Schwann cells secrete interleukin-18 upon IVIG stimulation and that this cytokine instructs these cells to promote axonal growth. Conclusions We conclude that IVIG can positively influence the Schwann cell differentiation process and that it enhances their regenerative potential.
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Affiliation(s)
- Nevena Tzekova
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Moorenstrasse 5, 40225, Düsseldorf, Germany.
| | - André Heinen
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Moorenstrasse 5, 40225, Düsseldorf, Germany.
| | - Sebastian Bunk
- Department of Immunology, Baxter Innovations GmbH, Vienna, Austria.
| | - Corinna Hermann
- Medical Affairs EMEA, Baxter Innovations GmbH, Vienna, Austria.
| | - Hans-Peter Hartung
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Moorenstrasse 5, 40225, Düsseldorf, Germany.
| | - Birgit Reipert
- Department of Immunology, Baxter Innovations GmbH, Vienna, Austria.
| | - Patrick Küry
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Moorenstrasse 5, 40225, Düsseldorf, Germany.
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12
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Klein D, Groh J, Weishaupt A, Martini R. Endogenous antibodies contribute to macrophage-mediated demyelination in a mouse model for CMT1B. J Neuroinflammation 2015; 12:49. [PMID: 25879857 PMCID: PMC4364634 DOI: 10.1186/s12974-015-0267-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 02/17/2015] [Indexed: 01/02/2023] Open
Abstract
Background We could previously identify components of both the innate and the adaptive immune system as disease modifiers in the pathogenesis of models for Charcot-Marie-Tooth (CMT) neuropathies type 1B and 1X. As part of the adaptive immune system, here we investigated the role of antibodies in a model for CMT1B. Methods Antibodies were localized and characterized in peripheral nerves of the CMT1B model by immunohistochemistry and Western blot analysis. Experimental ablation of antibodies was performed by cross breeding the CMT1B models with mutants deficient in B-lymphocytes (JHD−/− mutants). Ameliorated demyelination by antibody deficiency was reverted by intravenous injection of mouse IgG fractions. Histopathological analysis was performed by immunocytochemistry and light and quantitative electron microscopy. Results We demonstrate that in peripheral nerves of a mouse model for CMT1B, endogenous antibodies strongly decorate endoneurial tubes of peripheral nerves. These antibodies comprise IgG and IgM subtypes and are preferentially, but not exclusively, associated with nerve fiber aspects nearby the nodes of Ranvier. In the absence of antibodies, the early demyelinating phenotype is substantially ameliorated. Reverting the neuropathy by reconstitution with murine IgG fractions identified accumulating antibodies as potentially pathogenic at this early stage of disease. Conclusions Our study demonstrates that in a mouse model for CMT1B, endogenous antibodies contribute to early macrophage-mediated demyelination and disease progression. Thus, both the innate and adaptive immune system are mutually interconnected in a genetic model for demyelination. Since in Wallerian degeneration antibodies have also been shown to be involved in myelin phagocytosis, our study supports our view that inherited demyelination and Wallerian degeneration share common mechanisms, which are detrimental when activated under nonlesion conditions.
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Affiliation(s)
- Dennis Klein
- Department of Neurology, Developmental Neurobiology, University Hospital Würzburg, Josef-Schneider-Str 11, D-97080, Würzburg, Germany.
| | - Janos Groh
- Department of Neurology, Developmental Neurobiology, University Hospital Würzburg, Josef-Schneider-Str 11, D-97080, Würzburg, Germany.
| | - Andreas Weishaupt
- Department of Neurology, Developmental Neurobiology, University Hospital Würzburg, Josef-Schneider-Str 11, D-97080, Würzburg, Germany.
| | - Rudolf Martini
- Department of Neurology, Developmental Neurobiology, University Hospital Würzburg, Josef-Schneider-Str 11, D-97080, Würzburg, Germany.
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Tzekova N, Heinen A, Küry P. Molecules involved in the crosstalk between immune- and peripheral nerve Schwann cells. J Clin Immunol 2014; 34 Suppl 1:S86-104. [PMID: 24740512 DOI: 10.1007/s10875-014-0015-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 03/19/2014] [Indexed: 12/13/2022]
Abstract
Schwann cells are the myelinating glial cells of the peripheral nervous system and establish myelin sheaths on large caliber axons in order to accelerate their electrical signal propagation. Apart from this well described function, these cells revealed to exhibit a high degree of differentiation plasticity as they were shown to re- and dedifferentiate upon injury and disease as well as to actively participate in regenerative- and inflammatory processes. This review focuses on the crosstalk between glial- and immune cells observed in many peripheral nerve pathologies and summarizes functional evidences of molecules, regulators and factors involved in this process. We summarize data on Schwann cell's role presenting antigens, on interactions with the complement system, on Schwann cell surface molecules/receptors and on secreted factors involved in immune cell interactions or para-/autocrine signaling events, thus strengthening the view for a broader (patho) physiological role of this cell lineage.
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Affiliation(s)
- Nevena Tzekova
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Moorenstrasse 5, D-40225, Düsseldorf, Germany
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14
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Martini R, Klein D, Groh J. Similarities between inherited demyelinating neuropathies and Wallerian degeneration: an old repair program may cause myelin and axon perturbation under nonlesion conditions. THE AMERICAN JOURNAL OF PATHOLOGY 2013; 183:655-60. [PMID: 23831295 DOI: 10.1016/j.ajpath.2013.06.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 06/04/2013] [Accepted: 06/05/2013] [Indexed: 01/09/2023]
Abstract
Wallerian degeneration (WD) and inherited demyelinating neuropathies of the Charcot-Marie-Tooth type 1 (CMT1) appear to represent completely distinct events. CMT1-like diseases are chronic disorders of peripheral nerves that are genetically caused and lead to secondary neurodegenerative events, resulting in usually non-treatable disabilities, whereas WD is an acute, usually transient, reaction on injuries, aiming to allow peripheral nerve regeneration. Despite these differences, there are some striking similarities regarding molecular characteristics of neural cells in the affected peripheral nerves. The most conspicuous similarities might comprise the inflammatory component in both situations, as identified in appropriate mouse models. However, although inflammation is a beneficial component in WD, leading to removal of regrowth-repellent myelin debris, inflammation in CMT1 mouse models causes damage of initially intact nerve fibers. We hypothesize that, in CMT1 models, molecular pathways are activated that are shared with an important repair program after peripheral nerve injury, but lead to neural perturbation when activated under nonlesion conditions, as is the case in CMT1. These novel insights into the pathogenesis of CMT1 might be instrumental for the development of new therapeutic options in humans.
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Affiliation(s)
- Rudolf Martini
- Section of Developmental Neurobiology, Department of Neurology, University of Würzburg, Würzburg, Germany.
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Ydens E, Lornet G, Smits V, Goethals S, Timmerman V, Janssens S. The neuroinflammatory role of Schwann cells in disease. Neurobiol Dis 2013; 55:95-103. [DOI: 10.1016/j.nbd.2013.03.005] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 03/08/2013] [Accepted: 03/13/2013] [Indexed: 12/27/2022] Open
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Groh J, Kühl TG, Ip CW, Nelvagal HR, Sri S, Duckett S, Mirza M, Langmann T, Cooper JD, Martini R. Immune cells perturb axons and impair neuronal survival in a mouse model of infantile neuronal ceroid lipofuscinosis. Brain 2013; 136:1083-101. [DOI: 10.1093/brain/awt020] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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Somandin C, Gerber D, Pereira JA, Horn M, Suter U. LITAF (SIMPLE) regulates Wallerian degeneration after injury but is not essential for peripheral nerve development and maintenance: implications for Charcot-Marie-Tooth disease. Glia 2012; 60:1518-28. [PMID: 22729949 DOI: 10.1002/glia.22371] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 05/23/2012] [Indexed: 01/05/2023]
Abstract
Missense mutations affecting the LITAF gene (also known as SIMPLE) lead to the dominantly inherited peripheral neuropathy Charcot-Marie-Tooth disease type 1C (CMT1C). In this study, we sought to determine the requirement of Litaf function in peripheral nerves, the only known affected tissue in CMT1C. We reasoned that this knowledge is a prerequisite for a thorough understanding of the underlying disease mechanism with regard to potential contributions by Litaf loss of function. In addition, we anticipated to obtain valuable information about the basic function of the Litaf protein in peripheral nerves. To address these issues, we generated mice without Litaf expression using gene disruption in embryonic stem cells and analyzed Litaf-deficient peripheral nerves during development, in maintenance, and after injury. Our results show that Litaf function is not absolutely required for peripheral nerve development and maintenance. In injured nerves, however, we found that lack of Litaf led to increased numbers of macrophages during Wallerian degeneration, accelerated myelin destruction, and the emergence of more axonal sprouts. Consistent with these data, the migration of Litaf-deficient macrophages was increased upon chemokine stimulation. We conclude that loss of Litaf function is unlikely to be a major contributor to CMT1C, but modulating effects of macrophages need to be considered in the etiology of the disease.
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Affiliation(s)
- Christian Somandin
- Department of Biology, Institute of Molecular Health Sciences, Cell Biology, Swiss Federal Institute of Technology, ETH Zurich, CH-8093 Zurich, Switzerland
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Groh J, Weis J, Zieger H, Stanley ER, Heuer H, Martini R. Colony-stimulating factor-1 mediates macrophage-related neural damage in a model for Charcot-Marie-Tooth disease type 1X. Brain 2012; 135:88-104. [PMID: 22094537 PMCID: PMC3267979 DOI: 10.1093/brain/awr283] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Revised: 08/19/2011] [Accepted: 08/26/2011] [Indexed: 12/22/2022] Open
Abstract
Previous studies in our laboratory have shown that in models for three distinct forms of the inherited and incurable nerve disorder, Charcot-Marie-Tooth neuropathy, low-grade inflammation implicating phagocytosing macrophages mediates demyelination and perturbation of axons. In the present study, we focus on colony-stimulating factor-1, a cytokine implicated in macrophage differentiation, activation and proliferation and fostering neural damage in a model for Charcot-Marie-Tooth neuropathy 1B. By crossbreeding a model for the X-linked form of Charcot-Marie-Tooth neuropathy with osteopetrotic mice, a spontaneous null mutant for colony-stimulating factor-1, we demonstrate a robust and persistent amelioration of demyelination and axon perturbation. Furthermore, functionally important domains of the peripheral nervous system, such as juxtaparanodes and presynaptic terminals, were preserved in the absence of colony-stimulating factor-1-dependent macrophage activation. As opposed to other Schwann cell-derived cytokines, colony-stimulating factor-1 is expressed by endoneurial fibroblasts, as revealed by in situ hybridization, immunocytochemistry and detection of β-galactosidase expression driven by the colony-stimulating factor-1 promoter. By both light and electron microscopic studies, we detected extended cell-cell contacts between the colony-stimulating factor-1-expressing fibroblasts and endoneurial macrophages as a putative prerequisite for the effective and constant activation of macrophages by fibroblasts in the chronically diseased nerve. Interestingly, in human biopsies from patients with Charcot-Marie-Tooth type 1, we also found frequent cell-cell contacts between macrophages and endoneurial fibroblasts and identified the latter as main source for colony-stimulating factor-1. Therefore, our study provides strong evidence for a similarly pathogenic role of colony-stimulating factor-1 in genetically mediated demyelination in mice and Charcot-Marie-Tooth type 1 disease in humans. Thus, colony-stimulating factor-1 or its cognate receptor are promising target molecules for treating the detrimental, low-grade inflammation of several inherited neuropathies in humans.
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Affiliation(s)
- Janos Groh
- Department of Neurology, Section of Developmental Neurobiology, University of Würzburg, Josef-Schneiderstr. 11, 97080 Würzburg, Germany
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Shin YK, Jang SY, Lee HK, Jung J, Suh DJ, Seo SY, Park HT. Pathological adaptive responses of Schwann cells to endoplasmic reticulum stress in bortezomib-induced peripheral neuropathy. Glia 2011; 58:1961-76. [PMID: 20830808 DOI: 10.1002/glia.21065] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Bortezomib, a proteasome inhibitor, has been considered as a promising anticancer drug in the treatment of recurrent multiple myeloma and some solid tumors. The bortezomib-induced peripheral neuropathy (BIPN) is a prominent cause of dose-limiting toxicities after bortezomib treatment. In this study, we found that BIPN in a mouse model is characterized by acute but transient endoplasmic reticulum (ER) damages to Schwann cells. These damaged Schwann cells exhibit abnormal outcomes from healing processes such as the myelination of Remak bundles. A morphometric analysis of polymyelinated Remak bundles revealed that the pathological myelination was not related to the axonal parameters that regulate the normal myelination process during development. In addition, demyelinating macrophages were focally infiltrated within endoneurium of the sciatic nerve. To identify the mechanism underlying these pathologies, we applied a gene microarray analysis to bortezomib-treated primary Schwann cells and verified the changes of several gene expression in bortezomib-treated sciatic nerves. The analysis showed that bortezomib-induced ER stress was accompanied by the activation of several protective molecular chaperones and the down-regulation of myelin gene expression. ER stress inducers such as thapsigargin and bredelfin A also suppressed the mRNA expression of myelin gene P0 at transcriptional levels. In addition, the expression of chemokines such as the macrophage chemoattractants Ccl3 and Cxcl2 was significantly increased in Schwann cells in response to bortezomib and ER stress inducers. Taken together, these observations suggest that the pathological adaptive responses of Schwann cells to bortezomib-induced ER stress may, in part, participate in the development of BIPN.
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Affiliation(s)
- Yoon Kyung Shin
- Department of Physiology, Medical Science Research Institute, College of Medicine, Dong-A University, Busan, South Korea
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Groh J, Heinl K, Kohl B, Wessig C, Greeske J, Fischer S, Martini R. Attenuation of MCP-1/CCL2 expression ameliorates neuropathy in a mouse model for Charcot-Marie-Tooth 1X. Hum Mol Genet 2010; 19:3530-43. [PMID: 20591826 DOI: 10.1093/hmg/ddq269] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The chemokine monocyte chemoattractant protein-1 (MCP-1/CCL2) has been previously shown to be an important mediator of macrophage-related neural damage in models of two distinct inherited neuropathies, Charcot-Marie-Tooth (CMT) 1A and 1B. In mice deficient in the gap junction protein connexin 32 (Cx32def), an established model for the X-chromosome-linked dominant form of CMT (CMT1X), we investigated the role of the chemokine in macrophage immigration and neural damage by crossbreeding the Cx32def mice with MCP-1 knockout mutants. In Cx32def mutants typically expressing increased levels of MCP-1, macrophage numbers were strongly elevated, caused by an MCP-1-mediated influx of haematogenous macrophages. Curiously, the complete genetic deletion of MCP-1 did not cause reduced macrophage numbers in the nerves due to compensatory proliferation of resident macrophages. In contrast, and as already seen in other CMT models, heterozygous deletion of MCP-1 led to reduced numbers of phagocytosing macrophages and an alleviation of demyelination. Whereas alleviated demyelination was transient, axonal damage was persistently improved and even robust axonal sprouting was detectable at 12 months. Other axon-related features were alleviated electrophysiological parameters, reduced muscle denervation and atrophy, and increased muscle strength. Similar to models for CMT1A and CMT1B, we identified MEK-ERK signalling as mediating MCP-1 expression in Cx32-deficient Schwann cells. Blocking this pathway by the inhibitor CI-1040 caused reduced MCP-1 expression, attenuation of macrophage increase and amelioration of myelin- and axon-related alterations. Thus, attenuation of MCP-1 upregulation by inhibiting ERK phosphorylation might be a promising approach to treat CMT1X and other so far untreatable inherited peripheral neuropathies in humans.
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Affiliation(s)
- Janos Groh
- Department of Neurology, University of Wuerzburg, Wuerzburg, Germany
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Oberländer M, Berghoff M. Effects of the CC chemokine receptor 2 in mice deficient for the myelin protein zero (P0). Mol Cell Neurosci 2010; 45:59-65. [PMID: 20553884 DOI: 10.1016/j.mcn.2010.05.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Revised: 04/26/2010] [Accepted: 05/19/2010] [Indexed: 12/24/2022] Open
Abstract
In myelin protein zero (P0)-deficient mice immune cells are critically involved in the pathogenesis of a primary genetic disease. Previously it has been shown that the chemokine CCL2 affects the functional properties of endoneurial macrophages in heterozygous P0 mice. The aim of the present study was to characterize the role of the CCL2-receptor CCR2 in the pathogenesis of the neuropathy in P0 deficient mice. In demyelinating nerves of heterozygous P0 mice (P0+/-) CCR2-deficiency did not affect the number of endoneurial macrophages; there was a trend towards a higher number of activated macrophages. CCR2-deficiency resulted in an increased nerve demyelination. In dysmyelinating nerves of homozygous P0 mice (P0-/-), CCR2-deficiency led to a significant decrease of endoneurial macrophages but did not affect axonal degeneration. There was no effect of CCR2 on T-lymphocytes in both disease models. Our data confirm a functional role of the CCR2 receptor in the examined models of hereditary neuropathies. In P0+/- mutants CCR2 decreases macrophage activation and is protective against demyelination, whereas in P0-/- mice it increases the accumulation of endoneurial macrophages.
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Affiliation(s)
- Martina Oberländer
- Department of Neurology, University of Münster, Albert-Schweitzer-Str. 33, 48149 Münster, Germany.
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Kohl B, Fischer S, Groh J, Wessig C, Martini R. MCP-1/CCL2 modifies axon properties in a PMP22-overexpressing mouse model for Charcot-Marie-tooth 1A neuropathy. THE AMERICAN JOURNAL OF PATHOLOGY 2010; 176:1390-9. [PMID: 20093502 DOI: 10.2353/ajpath.2010.090694] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Charcot-Marie-Tooth 1A (CMT1A) neuropathy, the most common inherited peripheral neuropathy, is primarily caused by a gene duplication for the peripheral myelin protein-22 (PMP22). In an accordant mouse model, we investigated the role of monocyte chemoattractant protein-1 (MCP-1/CCL2) as a regulator of nerve macrophages and neural damage including axonopathy and demyelination. By generating PMP22tg mice with reduced levels or lack of MCP-1/CCL2, we found that MCP-1/CCL2 is involved in the increase of macrophages in mutant nerves. PMP22tg mice with wild-type levels of MCP-1/CCL2 showed strong macrophage increase in the diseased nerves, whereas either 50% reduction or total absence of MCP-1/CCL2 led to a moderate or a strong reduction of nerve macrophages, respectively. Interestingly, MCP-1/CCL2 expression level and macrophage numbers were correlated with features indicative of axon damage, such as maldistribution of K+ channels, reduced compound muscle action potentials, and muscle weakness. Demyelinating features, however, were most highly reduced when MCP-1/CCL2 was diminished by 50%, whereas complete lack of MCP-1/CCL2 showed an intermediate demyelinating phenotype. We also identified the MEK1/2-ERK1/2-pathway as being involved in MCP-1/CCL2 expression in the Schwann cells of the CMT1A model. Our data show that, in a CMT1A model, MCP-1/CCL2 activates nerve macrophages, mediates both axon damage and demyelination, and may thus be a promising target for therapeutic approaches.
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Affiliation(s)
- Bianca Kohl
- Department of Neurology University of Wuerzburg, Josef Schneider Strasse 11, 97080 Wuerzburg, Germany
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Lack of evidence for a pathogenic role of T-lymphocytes in an animal model for Charcot-Marie-Tooth disease 1A. Neurobiol Dis 2010; 38:78-84. [PMID: 20064611 DOI: 10.1016/j.nbd.2010.01.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Revised: 12/23/2009] [Accepted: 01/03/2010] [Indexed: 11/21/2022] Open
Abstract
We have previously shown that in two distinct models for inherited neuropathies of the Charcot-Marie-Tooth (CMT) type, T-lymphocytes are critically involved in demyelination. In the present study, we tested whether T-lymphocytes have a similar pathogenetic impact in another CMT model, i.e., in mice overexpressing the peripheral myelin protein (PMP)-22, representing the most prevalent form CMT1A. By cross breeding the myelin mutant mice with mutants lacking mature T- and B-lymphocytes (RAG-1-deficient mice), the pathological alterations were not changed in comparison to PMP22 mutants with a normal immune system. Reciprocal enhancement of lymphocyte activation, by inactivation of the lymphocytic co-inhibitor programmed death-1, also did not alter pathological changes, as opposed to models with approved lymphocytic involvement. These findings strongly suggest that lymphocytes are not pathogenetically relevant in this model for CMT1A. We suggest that - in contrast to myelin phagocytosing macrophages - T-lymphocytes are not a promising target for treatment of CMT1A.
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Barbaria EM, Kohl B, Buhren BA, Hasenpusch-Theil K, Kruse F, Küry P, Martini R, Müller HW. The α-chemokine CXCL14 is up-regulated in the sciatic nerve of a mouse model of Charcot–Marie–Tooth disease type 1A and alters myelin gene expression in cultured Schwann cells. Neurobiol Dis 2009; 33:448-58. [DOI: 10.1016/j.nbd.2008.11.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2008] [Revised: 10/30/2008] [Accepted: 11/28/2008] [Indexed: 10/21/2022] Open
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Müller M, Wacker K, Getts D, Ringelstein EB, Kiefer R. Further evidence for a crucial role of resident endoneurial macrophages in peripheral nerve disorders: lessons from acrylamide-induced neuropathy. Glia 2008; 56:1005-16. [PMID: 18383339 DOI: 10.1002/glia.20674] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Endoneurial macrophages are crucially involved in the pathogenesis of neuropathies. Historically, the macrophage response in neuropathies is believed to be of hematogenous origin. However, recent studies could demonstrate an intrinsic generation of the early macrophage response by resident endoneurial macrophages after traumatic nerve injury and in a model of hereditary neuropathy. We hypothesized that the local macrophage response might suffice to generate an appropriate macrophage response in mild neuropathies, supplemented by infiltrating macrophages only in severe nerve pathology. To clarify this assumption, we investigated the macrophage response in acrylamide-induced neuropathy as a model of a slowly progressive neuropathy with a defined onset. We induced the neuropathy in bone marrow chimeric mice carrying green fluorescent protein transgenic bone marrow, allowing the differentiation of resident (GFP(-)) and invading hematogenous endoneurial (GFP(+)) macrophages. Quantification of GFP(-) and GFP(+) endoneurial macrophages in the sciatic nerve revealed an increase only of resident macrophages in proximal parts, whereas in distal parts a minor additional influx of hematogenous macrophages was observed. The immunohistochemical profile of GFP(-) and GFP(+) macrophages was similar but distal GFP(-) macrophages were differentially activated than their GFP(+) counterparts. Characterization of CCR2-deficient mice revealed a function for this chemokine system in attracting hematogenous macrophages but not in generating the intrinsic macrophage response. In conclusion, we provide evidence for a role of resident macrophages in acrylamide-induced neuropathy. Resident endoneurial macrophages intrinsically generate the macrophage response in this slowly progressive neuropathy, which only becomes supplemented by hematogenous macrophages in distal areas of more pronounced damage.
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Affiliation(s)
- Marcus Müller
- Department of Neurology, Universitätsklinikum Münster, Münster, Germany.
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Martini R, Fischer S, López-Vales R, David S. Interactions between Schwann cells and macrophages in injury and inherited demyelinating disease. Glia 2008; 56:1566-1577. [DOI: 10.1002/glia.20766] [Citation(s) in RCA: 234] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Kroner A, Schwab N, Ip CW, Sommer C, Wessig C, Wiendl H, Martini R. The co-inhibitory molecule PD-1 modulates disease severity in a model for an inherited, demyelinating neuropathy. Neurobiol Dis 2008; 33:96-103. [PMID: 18996482 DOI: 10.1016/j.nbd.2008.09.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Revised: 08/27/2008] [Accepted: 09/20/2008] [Indexed: 12/14/2022] Open
Abstract
We have previously shown that mice heterozygously deficient for P0 are characterized by a late onset myelin disorder implicating CD8+ T-lymphocytes and macrophages. We now investigated the impact of the co-inhibitory molecule "programmed death" (PD)-1 (CD279), a CD28-related receptor expressed on activated T- and B-lymphocytes on the pathogenic phenotype of CD8+ T-lymphocytes in the P0 myelin mutants. PD-1 deficiency in P0+/- mice leads to a stronger increase of CD8+ T-lymphocytes and a substantially aggravated histological phenotype in the PNS compared to P0+/- mice expressing PD-1. Correspondingly, functional down-stream features, such as electrophysiological parameters, walking coordination and mechano-sensation are more affected than in PD-1-expressing myelin mutants. Our study demonstrates that a monogenic nerve disorder can be substantially modified by immune-controlling mechanisms. Thus, understanding the implication of disease-modifiers in inherited demyelination could be of pivotal interest for limiting the detrimental impact of primarily genetically-mediated myelin disorders by fostering immuno-regulatory pathways.
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Affiliation(s)
- Antje Kroner
- Department of Neurology, University of Wuerzburg, Wuerzburg
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Fischer S, Weishaupt A, Troppmair J, Martini R. Increase of MCP-1 (CCL2) in myelin mutant Schwann cells is mediated by MEK-ERK signaling pathway. Glia 2008; 56:836-43. [DOI: 10.1002/glia.20657] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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