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Moldovan M, Pisciotta C, Pareyson D, Krarup C. Myelin protein zero gene dose dependent axonal ion-channel dysfunction in a family with Charcot-Marie-Tooth disease. Clin Neurophysiol 2020; 131:2440-2451. [PMID: 32829291 DOI: 10.1016/j.clinph.2020.06.034] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 05/29/2020] [Accepted: 06/28/2020] [Indexed: 11/28/2022]
Abstract
OBJECTIVE The myelin impairment in demyelinating Charcot-Marie-Tooth (CMT) disease leads to various degrees of axonal degeneration, the ultimate cause of disability. We aimed to assess the pathophysiological changes in axonal function related to the neuropathy severity in hypo-/demyelinating CMT patients associated with myelin protein zero gene (MPZ) deficiency. METHODS We investigated four family members (two parents and two sons) harboring a frameshift mutation (c.306delA, p.Asp104ThrfsTer14) in the MPZ gene, predicted to result in a nonfunctional P0, by conventional conduction studies and multiple measures of motor axon excitability. In addition to the conventional excitability studies of the median nerve at the wrist, we tested the spinal accessory nerves. Control measures were obtained from 14 healthy volunteers. RESULTS The heterozygous parents (aged 56 and 63) had a mild CMT1B whereas their two homozygous sons (aged 31 and 39 years) had a severe Dejerine-Sottas disease phenotype. The spinal accessory nerve excitability could be measured in all patients. The sons showed reduced deviations during depolarizing threshold electrotonus and other depolarizing features which were not apparent in the accessory and median nerve studies of the parents. Mathematical modeling indicated impairment in voltage-gated sodium channels. This interpretation was supported by comparative modeling of excitability measurements in MPZ deficient mice. CONCLUSION Our data suggest that axonal depolarization in the context of abnormal voltage-gated sodium channels precedes axonal degeneration in severely hypo-/demyelinating CMT as previously reported in the mouse models. SIGNIFICANCE Measures of the accessory nerve excitability could provide pathophysiological markers of neurotoxicity in severe demyelinating neuropathies.
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Affiliation(s)
- Mihai Moldovan
- Department of Neuroscience, University of Copenhagen, Denmark; Department of Clinical Neurophysiology, Rigshospitalet, Copenhagen, Denmark
| | - Chiara Pisciotta
- Unit of Rare Neurodegenerative and Neurometabolic Diseases, Department of Clinical Neurosciences, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Davide Pareyson
- Unit of Rare Neurodegenerative and Neurometabolic Diseases, Department of Clinical Neurosciences, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Christian Krarup
- Department of Neuroscience, University of Copenhagen, Denmark; Department of Clinical Neurophysiology, Rigshospitalet, Copenhagen, Denmark.
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Stassart RM, Möbius W, Nave KA, Edgar JM. The Axon-Myelin Unit in Development and Degenerative Disease. Front Neurosci 2018; 12:467. [PMID: 30050403 PMCID: PMC6050401 DOI: 10.3389/fnins.2018.00467] [Citation(s) in RCA: 131] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 06/19/2018] [Indexed: 12/15/2022] Open
Abstract
Axons are electrically excitable, cable-like neuronal processes that relay information between neurons within the nervous system and between neurons and peripheral target tissues. In the central and peripheral nervous systems, most axons over a critical diameter are enwrapped by myelin, which reduces internodal membrane capacitance and facilitates rapid conduction of electrical impulses. The spirally wrapped myelin sheath, which is an evolutionary specialisation of vertebrates, is produced by oligodendrocytes and Schwann cells; in most mammals myelination occurs during postnatal development and after axons have established connection with their targets. Myelin covers the vast majority of the axonal surface, influencing the axon's physical shape, the localisation of molecules on its membrane and the composition of the extracellular fluid (in the periaxonal space) that immerses it. Moreover, myelinating cells play a fundamental role in axonal support, at least in part by providing metabolic substrates to the underlying axon to fuel its energy requirements. The unique architecture of the myelinated axon, which is crucial to its function as a conduit over long distances, renders it particularly susceptible to injury and confers specific survival and maintenance requirements. In this review we will describe the normal morphology, ultrastructure and function of myelinated axons, and discuss how these change following disease, injury or experimental perturbation, with a particular focus on the role the myelinating cell plays in shaping and supporting the axon.
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Affiliation(s)
- Ruth M. Stassart
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
- Department of Neuropathology, University Medical Center Leipzig, Leipzig, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
| | - Julia M. Edgar
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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Cashman CR, Hoke A. Deficiency of adaptive immunity does not interfere with Wallerian degeneration. PLoS One 2017; 12:e0177070. [PMID: 28475650 PMCID: PMC5419593 DOI: 10.1371/journal.pone.0177070] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 04/22/2017] [Indexed: 11/19/2022] Open
Abstract
Following injury, distal axons undergo the process of Wallerian degeneration, and then cell debris is cleared to create a permissive environment for axon regeneration. The innate and adaptive immune systems are believed to be critical for facilitating the clearance of myelin and axonal debris during this process. However, immunodeficient animal models are regularly used in transplantation studies investigating cell therapies to modulate the degenerative/regenerative response. Given the importance of the immune system in preparing a permissive environment for regeneration by clearing debris, animals lacking, in part or in full, a functional immune system may have an impaired ability to regenerate due to poor myelin clearance, and may, thus, be poor hosts to study modulators of regeneration and degeneration. To study this hypothesis, three different mouse models with impaired adaptive immunity were compared to wild type animals in their ability to degenerate axons and clear myelin debris one week following sciatic nerve transection. Immunofluorescent staining for axons and quantitation of axon density with nerve histomorphometry of the distal stump showed no consistent discrepancy between immunodeficient and wild type animals, suggesting axons tended to degenerate equally between the two groups. Debris clearance was assessed by macrophage density and relative myelin basic protein expression within the denervated nerve stump, and no consistent impairment of debris clearance was found. These data suggested deficiency of the adaptive immune system does not have a substantial effect on axon degeneration one week following axonal injury.
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Affiliation(s)
- Christopher R. Cashman
- MSTP/MD-PhD Program, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
- Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
| | - Ahmet Hoke
- Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
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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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Samsam M, Ahangari R, Naser SA. Pathophysiology of autism spectrum disorders: Revisiting gastrointestinal involvement and immune imbalance. World J Gastroenterol 2014; 20:9942-9951. [PMID: 25110424 PMCID: PMC4123375 DOI: 10.3748/wjg.v20.i29.9942] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 05/22/2014] [Accepted: 06/13/2014] [Indexed: 02/06/2023] Open
Abstract
Autism spectrum disorders (ASD) comprise a group of neurodevelopmental abnormalities that begin in early childhood and are characterized by impairment of social communication and behavioral problems including restricted interests and repetitive behaviors. Several genes have been implicated in the pathogenesis of ASD, most of them are involved in neuronal synaptogenesis. A number of environmental factors and associated conditions such as gastrointestinal (GI) abnormalities and immune imbalance have been linked to the pathophysiology of ASD. According to the March 2012 report released by United States Centers for Disease Control and Prevention, the prevalence of ASD has sharply increased during the recent years and one out of 88 children suffers now from ASD symptoms. Although there is a strong genetic base for the disease, several associated factors could have a direct link to the pathogenesis of ASD or act as modifiers of the genes thus aggravating the initial problem. Many children suffering from ASD have GI problems such as abdominal pain, chronic diarrhea, constipation, vomiting, gastroesophageal reflux, and intestinal infections. A number of studies focusing on the intestinal mucosa, its permeability, abnormal gut development, leaky gut, and other GI problem raised many questions but studies were somehow inconclusive and an expert panel of American Academy of Pediatrics has strongly recommended further investigation in these areas. GI tract has a direct connection with the immune system and an imbalanced immune response is usually seen in ASD children. Maternal infection or autoimmune diseases have been suspected. Activation of the immune system during early development may have deleterious effect on various organs including the nervous system. In this review we revisited briefly the GI and immune system abnormalities and neuropeptide imbalance and their role in the pathophysiology of ASD and discussed some future research directions.
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Krieger F, Elflein N, Saenger S, Wirthgen E, Rak K, Frantz S, Hoeflich A, Toyka KV, Metzger F, Jablonka S. Polyethylene glycol-coupled IGF1 delays motor function defects in a mouse model of spinal muscular atrophy with respiratory distress type 1. Brain 2014; 137:1374-93. [DOI: 10.1093/brain/awu059] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Abstract
The peripheral nervous system (PNS) comprises the cranial nerves, the spinal nerves with their roots and rami, dorsal root ganglia neurons, the peripheral nerves, and peripheral components of the autonomic nervous system. Cell-mediated or antibody-mediated immune attack on the PNS results in distinct clinical syndromes, which are classified based on the tempo of illness, PNS component(s) involved, and the culprit antigen(s) identified. Insights into the pathogenesis of autoimmune neuropathy have been provided by ex vivo immunologic studies, biopsy materials, electrophysiologic studies, and experimental models. This review article summarizes earlier seminal observations and highlights the recent progress in our understanding of immunopathogenesis of autoimmune neuropathies based on data from animal models.
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Affiliation(s)
- Betty Soliven
- Address correspondence and reprint requests to Dr. Betty Soliven, Room S225, Department of Neurology MC2030, University of Chicago, 5841 S. Maryland Avenue, Chicago, IL 60637 or
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Bouhy D, Timmerman V. Animal models and therapeutic prospects for Charcot-Marie-Tooth disease. Ann Neurol 2013; 74:391-6. [PMID: 23913540 DOI: 10.1002/ana.23987] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 07/04/2013] [Accepted: 07/29/2013] [Indexed: 12/14/2022]
Abstract
Charcot-Marie-Tooth (CMT) neuropathies are inherited neuromuscular disorders caused by a length-dependent neurodegeneration of peripheral nerves. More than 900 mutations in 60 different genes are causative of the neuropathy. Despite significant progress in therapeutic strategies, the disease remains incurable. The increasing number of genes linked to the disease, and their considerable clinical and genetic heterogeneity render the development of these strategies particularly challenging. In this context, cellular and animals models provide powerful tools. Efficient motor and sensory tests have been developed to assess the behavioral phenotype in transgenic animal models (rodent and fly). When these models reproduce a phenotype comparable to CMT, they allow therapeutic approaches and the discovery of modifiers and biomarkers. In this review, we describe the most convincing transgenic rodent and fly models of CMT and how they can lead to clinical trial. We also discuss the challenges that the research, the clinic, and the pharmaceutical industry will face in developing efficient and accessible treatment for CMT patients.
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Affiliation(s)
- Delphine Bouhy
- Peripheral Neuropathy Group, Department of Molecular Genetics, Flanders Interuniversity Institute for Biotechnology, Institute Born Bunge, University of Antwerp, Antwerp, Belgium
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Bouhy D, Timmerman V. Modèles animaux dans la maladie de Charcot-Marie-Tooth et applications de la compréhension de la maladie chez l’homme. Rev Neurol (Paris) 2013; 169:971-7. [DOI: 10.1016/j.neurol.2013.07.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 07/25/2013] [Accepted: 07/26/2013] [Indexed: 11/26/2022]
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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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Fledrich R, Stassart RM, Sereda MW. Murine therapeutic models for Charcot-Marie-Tooth (CMT) disease. Br Med Bull 2012; 102:89-113. [PMID: 22551516 DOI: 10.1093/bmb/lds010] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
INTRODUCTION OR BACKGROUND Charcot-Marie-Tooth (CMT) disease represents a broad group of inherited motor and sensory neuropathies which can originate from various genetic aberrations, e.g. mutations, deletions and duplications. SOURCES OF DATA We performed a literature review on murine animal models of CMT disease with regard to experimental therapeutic approaches. Hereby, we focussed on the demyelinating subforms of CMT (CMT1). PubMed items were CMT, animal model, demyelination and therapy. AREAS OF AGREEMENT Patients affected by CMT suffer from slowly progressive, distally pronounced muscle atrophy caused by an axonal loss. The disease severity is highly variable and impairments may result in wheelchair boundness. No therapy is available yet. AREAS OF CONTROVERSY Numerous rodent models for the various CMT subtypes are available today. The selection of the correct animal model for the specific CMT subtype provides an important prerequisite for the successful translation of experimental findings in patients. GROWING POINTS Despite more than 20 years of remarkable progress in CMT research, the disease is still left untreatable. There is a growing number of experimental therapeutic strategies that may be translated into future clinical trials in patients with CMT. AREAS TIMELY FOR DEVELOPING RESEARCH The slow disease progression and insensitive outcome measures hamper clinical therapy trials in CMT. Biomarkers may provide powerful tools to monitor therapeutic efficacy. Recently, we have shown that transcriptional profiling can be utilized to assess and predict the disease severity in a transgenic rat model and in affected humans.
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Affiliation(s)
- Robert Fledrich
- Research Group 'Molecular and Translational Neurology', Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
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Vasculitis-like neuropathy in amyotrophic lateral sclerosis unresponsive to treatment. Acta Neuropathol 2011; 122:343-52. [PMID: 21626035 DOI: 10.1007/s00401-011-0837-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 05/08/2011] [Accepted: 05/13/2011] [Indexed: 10/18/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disease with variable involvement of other systems. A pathogenetic role of immune-mediated mechanisms has been suggested. We retrospectively analyzed sural nerve pathology and the clinical course in 18 patients with ALS. These patients had undergone sural nerve biopsy because of clinical or neurophysiological signs indicating sensory involvement (ALS+). Eleven of the 18 ALS+ patients had inflammatory cell infiltrates (ALS(vasc)) resembling infiltrates seen in patients with vasculitic neuropathy. Data were compared with the 7 patients without vasculitic infiltrates (ALS(nonvasc)) and with those of 16 patients with isolated peripheral nerve vasculitis (NP(vasc)). Biopsy specimens were processed with standard histological stains and with immunohistochemistry for a panel of inflammatory markers, with the hypothesis that the composition of infiltrates should differ between ALS(vasc) and NP(vasc). Immunoreactive cells were quantified in a blinded manner. Unlike patients with NP(vasc), those with ALS(vasc) had only minor neurophysiological abnormalities in the sural nerve and, except for the infiltrates, almost normal nerve morphology on semithin sections. The difference in epineurial T cell count was significant between ALS(vasc) and ALS(nonvasc) (p = 0.031). Surprisingly, the cellular composition of epineurial infiltrates in sural nerve biopsies was indistinguishable between ALS(vasc) and NP(vasc) despite a significant difference in fiber pathology (p < 0.0001). Standard immunosuppressive treatment did not prevent clinical progression of the motor neuron disease in any of the patients with ALS(vasc). ALS(vasc) appears as a neuropathological subtype in ALS+ suggesting immune-mediated disease components but without response to standard immunosuppressive treatment.
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Müller M, Leonhard C, Krauthausen M, Wacker K, Kiefer R. On the longevity of resident endoneurial macrophages in the peripheral nervous system: a study of physiological macrophage turnover in bone marrow chimeric mice. J Peripher Nerv Syst 2010; 15:357-65. [DOI: 10.1111/j.1529-8027.2010.00295.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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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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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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Kroner A, Ip CW, Thalhammer J, Nave KA, Martini R. Ectopic T-cell specificity and absence of perforin and granzyme B alleviate neural damage in oligodendrocyte mutant mice. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 176:549-55. [PMID: 20042681 DOI: 10.2353/ajpath.2010.090722] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In transgenic mice overexpressing the major myelin protein of the central nervous system, proteolipid protein, CD8+ T-lymphocytes mediate the primarily genetically caused myelin and axon damage. In the present study, we investigated the cellular and molecular mechanisms underlying this immune-related neural injury. At first, we investigated whether T-cell receptors (TCRs) are involved in these processes. For this purpose, we transferred bone marrow from mutants carrying TCRs with an ectopic specificity to ovalbumin into myelin mutant mice that also lacked normal intrinsic T-cells. T-lymphocytes with ovalbumin-specific TCRs entered the mutant central nervous system to a similar extent as T-lymphocytes from wild-type mice. However, as revealed by histology, electron microscopy and axon- and myelin-related immunocytochemistry, these T-cells did not cause neural damage in the myelin mutants, reflecting the need for specific antigen recognition by cytotoxic CD8+ T-cells. By chimerization with bone marrow from perforin- or granzyme B (Gzmb)-deficient mice, we demonstrated that absence of these cytotoxic molecules resulted in reduced neural damage in myelin mutant mice. Our study strongly suggests that pathogenetically relevant immune reactions in proteolipid protein-overexpressing mice are TCR-dependent and mediated by the classical components of CD8+ T-cell cytotoxicity, perforin, and Gzmb. These findings have high relevance with regard to our understanding of the pathogenesis of disorders primarily caused by genetically mediated oligodendropathy.
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Affiliation(s)
- Antje Kroner
- Department of Neurology, Section of Developmental Neurobiology, University of Wuerzburg, Josef-Schneider Str. 11, D-97080 Wuerzburg, Germany
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Meyer zu Hörste G, Heidenreich H, Mausberg AK, Lehmann HC, ten Asbroek ALMA, Saavedra JT, Baas F, Hartung HP, Wiendl H, Kieseier BC. Mouse Schwann cells activate MHC class I and II restricted T-cell responses, but require external peptide processing for MHC class II presentation. Neurobiol Dis 2009; 37:483-90. [PMID: 19914379 DOI: 10.1016/j.nbd.2009.11.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Revised: 11/04/2009] [Accepted: 11/06/2009] [Indexed: 11/30/2022] Open
Abstract
Schwann cells are the myelinating glia cells of the peripheral nervous system (PNS). In inflammatory neuropathies like the Guillain-Barré syndrome (GBS) Schwann cells become target of an autoimmune response, but may also modulate local inflammation. Here, we tested the functional relevance of Schwann cell derived MHC expression in an in vitro coculture system. Mouse Schwann cells activated proliferation of ovalbumin specific CD8+ T cells when ovalbumin protein or MHC class I restricted ovalbumin peptide (Ova(257-264) SIINFEKL) was added and after transfection with an ovalbumin coding vector. Schwann cells activated proliferation of ovalbumin specific CD4+ T cells in the presence of MHC class II restricted ovalbumin peptide (Ova(323-339) ISQAVHAAHAEINEAGR). CD4+ T-cell proliferation was not activated by ovalbumin protein or transfection with an ovalbumin coding vector. This indicates that Schwann cells express functionally active MHC class I and II molecules. In this study, however, Schwann cells lacked the ability to process exogenous antigen or cross-present endogenous antigen into the MHC class II presentation pathway. Thus, antigen presentation may be a pathological function of Schwann cells exacerbating nerve damage in inflammatory neuropathies.
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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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Ip CW, Kroner A, Kohl B, Wessig C, Martini R. Tacrolimus (FK506) causes disease aggravation in models for inherited peripheral myelinopathies. Neurobiol Dis 2008; 33:207-12. [PMID: 19028581 DOI: 10.1016/j.nbd.2008.10.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2008] [Revised: 10/07/2008] [Accepted: 10/13/2008] [Indexed: 01/10/2023] Open
Abstract
Mice hetero- or homozygously deficient for myelin protein zero (P0+/-, P0-/- mice) are models for distinct forms of inherited de- or dysmyelinating neuropathies, respectively. P0+/- mice show a demyelinating neuropathy with a pathogenetic implication of CD8+ T-lymphocytes and macrophages, while P0-/- mice show dysmyelination with axonal loss. It was, therefore, of interest to treat both mutants with FK506 (Tacrolimus), an agent with immunosuppressive and neuroprotective properties. Treatment of P0+/- mice led to an aggravation of demyelination, without affecting nervous CD8+ T-lymphocytes, but reducing splenic CD4+ cells. Treatment of P0-/- mice resulted in a substantial increase of the dysmyelination-related axon loss. Treatment of wildtype mice did not cause pathological changes in peripheral nerves. Our study shows that FK506 may not be suitable for the treatment of the human nerve disorders. Furthermore, when used as an immunosuppressant, the drug may generate detrimental neurological side effects in patients with an additional hereditary neuropathy.
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Affiliation(s)
- Chi Wang Ip
- Department of Neurology, Developmental Neurobiology, University of Wuerzburg, Josef-Schneider-Str. 11, D-97080 Wuerzburg, Germany
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20
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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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21
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Meyer zu Hörste G, Hu W, Hartung HP, Lehmann HC, Kieseier BC. The immunocompetence of Schwann cells. Muscle Nerve 2007; 37:3-13. [PMID: 17823955 DOI: 10.1002/mus.20893] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Schwann cells are the myelinating glial cells of the peripheral nervous system that support and ensheath axons with myelin to enable rapid saltatory signal propagation in the axon. Immunocompetence, however, has only recently been recognized as an important feature of Schwann cells. An autoimmune response against components of the peripheral nervous system triggers disabling inflammatory neuropathies in patients and corresponding animal models. The immune system participates in nerve damage and disease manifestation even in non-inflammatory hereditary neuropathies. A growing body of evidence suggests that Schwann cells may modulate local immune responses by recognizing and presenting antigens and may also influence and terminate nerve inflammation by secreting cytokines. This review summarizes current knowledge on the interaction of Schwann cells with the immune system, which is involved in diseases of the peripheral nervous system.
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Affiliation(s)
- Gerd Meyer zu Hörste
- Department of Neurology, Heinrich-Heine-University, Moorenstrasse 5, 40225 Düsseldorf, Germany
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Ey B, Kobsar I, Blazyca H, Kroner A, Martini R. Visualization of degenerating axons in a dysmyelinating mouse mutant with axonal loss. Mol Cell Neurosci 2007; 35:153-60. [PMID: 17383197 DOI: 10.1016/j.mcn.2007.02.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Accepted: 02/13/2007] [Indexed: 01/27/2023] Open
Abstract
Mice homozygously deficient for the myelin component P0 show loss of axons in peripheral nerves. In order to investigate the morphological characteristics of degenerating axons, we crossbred the myelin mutants with a transgenic mouse line expressing yellow fluorescent protein (YFP) in a small proportion of neurons. Peripheral nerves of the double mutants were prepared into small fiber bundles and investigated by fluorescence microscopy. We could identify the tips of degenerating axon as bulb-like structures. Additionally, by electron microscopy, these structures were characterized as axoplasmic extensions containing numerous membraneous compartments. By immunoelectron microscopy, the degenerating end bulbs were in contact with ensheathing Schwann cells that contained YFP-immunoreactivity possibly reflecting phagocytosis of axon material by these cells. Immunohistochemistry using antibodies against macrophages revealed that YFP-positive bulbs, but also other axonal swellings, were often associated with macrophages supporting our previous findings that myelin-related axonal loss is partially mediated by these cells.
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Affiliation(s)
- Birgit Ey
- Department of Neurology, Developmental Neurobiology, University of Wuerzburg, Josef-Schneiderstr. 11, D-97080 Wuerzburg, Germany
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23
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Abstract
PURPOSE OF REVIEW The aim of this review is to describe the local immune circuitry in the peripheral nervous system and its dialogue with systemic immunity under pathological conditions. Specifically, interactions of the immune system with cellular and extracellular components within peripheral nerve and immune functions of tissue-resident endoneurial macrophages and Schwann cells will be discussed. RECENT FINDINGS New insights into the elements involved in the pathogenesis of immune-mediated disorders of the peripheral nervous system provide a better understanding of the complex interplay of these cellular and molecular components in the immunology of the peripheral nervous system. SUMMARY The application of innovative and cutting-edge technologies to the study of immunoinflammatory disorders of the peripheral nervous system provides a better understanding of underlying principles of the organization of the immune network present in the peripheral nerve and its dialogue with the systemic immune system. This may foster the development of specific and highly effective therapies for immune-mediated disorders of the peripheral nerve.
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Affiliation(s)
- Bernd C Kieseier
- Department of Neurology, Heinrich-Heine-University, Düsseldorf, Germany
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Abstract
PURPOSE OF REVIEW Mutations in a number of genes have been associated with inherited neuropathies (Charcot-Marie-Tooth or CMT disease). This review highlights how animal models of demyelinating CMT have improved our understanding of disease mechanisms. Transgenic CMT models also allow therapies to be developed in a preclinical setting. RECENT FINDINGS Rodent models for the most common subtypes of human CMT disease are now available, and two mouse mutants modeling the rare CMT4B subform have lately extended this repertoire. In a peripheral myelin protein 22 kDa (Pmp22) transgenic rat model of CMT1A, administration of a progesterone receptor antagonist reduced Pmp22 overexpression, axon loss and clinical impairments. Dietary ascorbic acid prevented dysmyelination and premature death in a Pmp22 transgenic mouse line. Neurotrophin-3 promoted small fiber remyelination in CMT1A xenografts and sensory functions in CMT1A patients. Gene expression profiling in rodent models of CMT may identify further therapeutical targets. While original classifications distinguish the demyelinating and axonal forms of CMT, recent findings emphasize that axon loss is a common feature, possibly caused by Schwann cell defects rather than demyelination per se. This supports our model that myelination and long-term axonal support are distinct functions of all myelinating glial cells. SUMMARY Animal models have opened up new perspectives on the pathomechanisms and possible treatment strategies of inherited neuropathies.
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Limaye A, Koya V, Samsam M, Daniell H. Receptor-mediated oral delivery of a bioencapsulated green fluorescent protein expressed in transgenic chloroplasts into the mouse circulatory system. FASEB J 2006; 20:959-61. [PMID: 16603603 PMCID: PMC3481851 DOI: 10.1096/fj.05-5134fje] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Oral delivery of biopharmaceutical proteins expressed in plant cells should reduce their cost of production, purification, processing, cold storage, transportation, and delivery. However, poor intestinal absorption of intact proteins is a major challenge. To overcome this limitation, we investigate here the concept of receptor-mediated oral delivery of chloroplast-expressed foreign proteins. Therefore, the transmucosal carrier cholera toxin B-subunit and green fluorescent protein (CTB-GFP), separated by a furin cleavage site, was expressed via the tobacco chloroplast genome. Polymerase chain reaction (PCR) and Southern blot analyses confirmed site-specific transgene integration and homoplasmy. Immunoblot analysis and ELISA confirmed expression of monomeric and pentameric forms of CTB-GFP, up to 21.3% of total soluble proteins. An in vitro furin cleavage assay confirmed integrity of the engineered furin cleavage site, and a GM1 binding assay confirmed the functionality of CTB-GFP pentamers. Following oral administration of CTB-GFP expressing leaf material to mice, GFP was observed in the mice intestinal mucosa, liver, and spleen in fluorescence and immunohistochemical studies, while CTB remained in the intestinal cell. This report of receptor-mediated oral delivery of a foreign protein into the circulatory system opens the door for low-cost production and delivery of human therapeutic proteins.
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Affiliation(s)
| | | | - Mohtashem Samsam
- Department of Molecular Biology and Microbiology, University of Central Florida, Biomolecular Science, Orlando, Florida, USA
| | - Henry Daniell
- Department of Molecular Biology and Microbiology, University of Central Florida, Biomolecular Science, Orlando, Florida, USA
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Wang Ip C, Kroner A, Fischer S, Berghoff M, Kobsar I, Mäurer M, Martini R. Role of immune cells in animal models for inherited peripheral neuropathies. Neuromolecular Med 2006; 8:175-90. [PMID: 16775375 DOI: 10.1385/nmm:8:1-2:175] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2005] [Revised: 11/10/2005] [Accepted: 11/15/2005] [Indexed: 12/20/2022]
Abstract
Mice expressing half of the normal dose of protein zero (P0+/- mice) or completely deficient gap-junction protein connexin 32 -/- mice mimic demyelinating forms of inherited neuropathies, such as Charcot-Marie-Tooth (CMT) neuropathies type 1B and CMT type 1X, respectively. In both models, an almost normal myelin formation is observed during the first months of life, followed by a slowly progressing demyelinating neuropathy. In both models, there is a substantial increase of CD8+ T-lymphocytes and macrophages within the demyelinating nerves. Recently, this has also been observed in mice mildly overexpressing human peripheral myelin protein 22 kD mimicking the most common form of CMT, CMT type 1A. In all demyelinating models, the macrophages show close contacts with intact myelin sheaths or demyelinated axons, suggesting an active role of these cells in myelin degeneration. Additionally, fibroblast-like cells contact macrophages, suggesting a functional role of fibroblast-like cells in macrophage activation. By cross-breeding P0+/- and gap-junction protein connexin 32-/- mice with immunodeficient recombination activating gene-1-deficient mutants, a substantial alleviation of the demyelinating phenotype was observed. Similarly, cross-breeding of P0+/- mice with mutants with a defect in macrophage activation led to an alleviated phenotype as well. These findings demonstrate that the immune system is involved in the pathogenesis of demyelinating neuropathies. In contrast, in P0-/- mice, which display a compromised myelin compaction and axonal loss from onset, immune cells appear to have a neuroprotective effect because cross-breeding with recombination activating gene-1 mutants leads to an aggravation of axonopathic changes. In the present review, we discuss the influence of the immune system on inherited de- and dysmyelination regarding disease mechanisms and possible clinical implications.
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Affiliation(s)
- Chi Wang Ip
- Department of Neurology, Developmental Neurobiology, University of Wuerzburg, Josef-Schneider-Str. 11, D-97080 Wuerzburg, Germany
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Köller H, Schroeter M, Kieseier BC, Hartung HP. Chronic inflammatory demyelinating polyneuropathy – update on pathogenesis, diagnostic criteria and therapy. Curr Opin Neurol 2005; 18:273-8. [PMID: 15891411 DOI: 10.1097/01.wco.0000169744.14288.d1] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW Chronic inflammatory demyelinating polyneuropathy (CIDP) is a treatable but possibly underdiagnosed disorder of the peripheral nerve. This review covers the growing literature of the past years that deals with the pathogenesis, diagnostic criteria and treatment of CIDP. RECENT FINDINGS The recent development of a biphasic animal model of experimental autoimmune neuritis may provide further insights into the pathogenesis of inflammatory demyelination of the peripheral nerve, such as in CIDP, and may allow the development of further innovative therapeutic strategies. In patients, the contribution of immune processes to the dysfunction in hereditary polyneuropathies and the association of hereditary neuropathy and CIDP has been described. Commonly used therapies remain corticosteroids, intravenous immunoglobulin and plasmapheresis; however, newer immunosuppressant approaches using mycophenolate mofetil or cyclosporin A, or immunomodulating therapies using monoclonal antibodies or interferons are presently under investigation. SUMMARY The growing body of knowledge on the pathogenesis of CIDP and further diagnostic differentiation of subforms may help to develop more-effective therapies for CIDP in the next few years.
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Affiliation(s)
- Hubertus Köller
- Department of Neurology, Heinrich-Heine-University, Düsseldorf, Germany
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Kobsar I, Hasenpusch-Theil K, Wessig C, Müller HW, Martini R. Evidence for macrophage-mediated myelin disruption in an animal model for Charcot-Marie-Tooth neuropathy type 1A. J Neurosci Res 2005; 81:857-64. [PMID: 16041800 DOI: 10.1002/jnr.20601] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Charcot-Marie-Tooth neuropathy type 1A (CMT 1 A) is the most common inherited neuropathy in humans and is mostly caused by a 1.5-Mb tandem duplication of chromosome 17 comprising the gene for the peripheral myelin protein 22-kDa (PMP 22). Although there are numerous studies on the functional role of PMP 22, the mechanisms of myelin degeneration under PMP 22-overexpression conditions have not yet been fully understood. We have shown previously that in mouse mutants hetero- or homozygously deficient for two other myelin components, P0 and C x 32, respectively, immune cells contribute to the demyelinating neuropathy. To test this possibility for PMP 22 overexpression, we investigated a putative mouse model for CMT 1 A, i.e., the mouse strain C 6 1 mildly overexpressing human PMP 22 in peripheral nerves. Electron microscopic and electrophysiologic investigations revealed that this mouse strain develops pathologic features similar to those found in CMT 1 A patients. A novel finding, however, was the upregulation of CD8- and F4/80-positive lymphocytes and macrophages, respectively, in peripheral nerves. The observation that macrophages enter endoneurial tubes of the mutants and obviously phagocytose morphologically normal myelin strongly suggests that the myelin degeneration is mediated at least partially by these phagocytic cells. By gene array technology and quantitative RT-PCR of peripheral nerve homogenates from PMP 22 mutants, monocyte chemoattractant protein-1 (MCP-1; cc l2) could be identified as a putative factor to attract or activate macrophages that attack myelin sheaths in this model of CMT 1 A.
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Affiliation(s)
- Igor Kobsar
- Developmental Neurobiology, Department of Neurology, University of Würzburg, Würzburg, Germany
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