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Koike H, Furukawa S, Mouri N, Fukami Y, Iijima M, Katsuno M. Dosage effects of PMP22 on nonmyelinating Schwann cells in hereditary neuropathy with liability to pressure palsies. Neuromuscul Disord 2022; 32:503-511. [DOI: 10.1016/j.nmd.2022.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 04/01/2022] [Accepted: 04/05/2022] [Indexed: 11/28/2022]
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Moss KR, Bopp TS, Johnson AE, Höke A. New evidence for secondary axonal degeneration in demyelinating neuropathies. Neurosci Lett 2021; 744:135595. [PMID: 33359733 PMCID: PMC7852893 DOI: 10.1016/j.neulet.2020.135595] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 10/31/2020] [Accepted: 12/19/2020] [Indexed: 12/28/2022]
Abstract
Development of peripheral nervous system (PNS) myelin involves a coordinated series of events between growing axons and the Schwann cell (SC) progenitors that will eventually ensheath them. Myelin sheaths have evolved out of necessity to maintain rapid impulse propagation while accounting for body space constraints. However, myelinating SCs perform additional critical functions that are required to preserve axonal integrity including mitigating energy consumption by establishing the nodal architecture, regulating axon caliber by organizing axonal cytoskeleton networks, providing trophic and potentially metabolic support, possibly supplying genetic translation materials and protecting axons from toxic insults. The intermediate steps between the loss of these functions and the initiation of axon degeneration are unknown but the importance of these processes provides insightful clues. Prevalent demyelinating diseases of the PNS include the inherited neuropathies Charcot-Marie-Tooth Disease, Type 1 (CMT1) and Hereditary Neuropathy with Liability to Pressure Palsies (HNPP) and the inflammatory diseases Acute Inflammatory Demyelinating Polyneuropathy (AIDP) and Chronic Inflammatory Demyelinating Polyneuropathy (CIDP). Secondary axon degeneration is a common feature of demyelinating neuropathies and this process is often correlated with clinical deficits and long-lasting disability in patients. There is abundant electrophysiological and histological evidence for secondary axon degeneration in patients and rodent models of PNS demyelinating diseases. Fully understanding the involvement of secondary axon degeneration in these diseases is essential for expanding our knowledge of disease pathogenesis and prognosis, which will be essential for developing novel therapeutic strategies.
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Affiliation(s)
- Kathryn R Moss
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Taylor S Bopp
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Anna E Johnson
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Ahmet Höke
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD, United States.
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Jouaud M, Mathis S, Richard L, Lia AS, Magy L, Vallat JM. Rodent models with expression of PMP22: Relevance to dysmyelinating CMT and HNPP. J Neurol Sci 2019; 398:79-90. [PMID: 30685714 DOI: 10.1016/j.jns.2019.01.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 12/26/2018] [Accepted: 01/16/2019] [Indexed: 02/02/2023]
Abstract
BACKGROUND Charcot-Marie-Tooth diseases (CMT) are due to abnormalities of many genes, the most frequent being linked to PMP22 (Peripheral Myelin Protein 22). In the past, only spontaneous genetic anomalies occurring in mouse mutants such as Trembler (Tr) mice were available; more recently, several rodent models have been generated for exploration of the pathophysiological mechanisms underlying these neuropathies. METHODS Based on the personal experience of our team, we describe here the pathological hallmarks of most of these animal models and compare them to the pathological features observed in some CMT patient nerves (CMT types 1A and E; hereditary neuropathy with liability to pressure palsies, HNPP). RESULTS We describe clinical data and detailed pathological analysis mainly by electron microscopy of the sciatic nerves of these animal models conducted in our laboratory; lesions of PMP22 deficient animals (KO and mutated PMP22) and PMP22 overexpressed models are described and compared to ultrastructural anomalies of nerve biopsies from CMT patients due to PMP22 gene anomalies. It is of note that while there are some similarities, there are also significant differences between the lesions in animal models and human cases. Such observations highlight the complex roles played by PMP22 in nerve development. CONCLUSION It should be borne in mind that we require additional correlations between animal models of hereditary neuropathies and CMT patients to rationalize the development of efficient drugs.
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Affiliation(s)
- Maxime Jouaud
- Equipe d'accueil 6309, Maintenance myélinique et Neuropathies périphériques, University of Limoges, 2 rue du Docteur Raymond Marcland, 87000 Limoges, France
| | - Stéphane Mathis
- Department of Neurology, Nerve-Muscle Unit, CHU Bordeaux (Pellegrin University Hospital), place Amélie Raba-Léon, 33000 Bordeaux, France; National Reference Center 'maladies neuromusculaires du Grand Sud-ouest', CHU Bordeaux (Pellegrin University Hospital), place Amélie Raba-Léon, 33000 Bordeaux, France
| | - Laurence Richard
- Department of Neurology, CHU Limoges, Dupuytren University Hospital, 2 avenue Martin Luther King, 87042 Limoges, France; National Reference Center for 'Rare Peripheral Neuropathies', CHU Limoges, Dupuytren University Hospital, 2 avenue Martin Luther King, 87042 Limoges, France
| | - Anne-Sophie Lia
- Equipe d'accueil 6309, Maintenance myélinique et Neuropathies périphériques, University of Limoges, 2 rue du Docteur Raymond Marcland, 87000 Limoges, France; Department of Biochemistry and Molecular Genetics, CHU Limoges, Dupuytren University Hospital, 2 avenue Martin Luther King, 87042 Limoges, France
| | - Laurent Magy
- Department of Neurology, CHU Limoges, Dupuytren University Hospital, 2 avenue Martin Luther King, 87042 Limoges, France; National Reference Center for 'Rare Peripheral Neuropathies', CHU Limoges, Dupuytren University Hospital, 2 avenue Martin Luther King, 87042 Limoges, France
| | - Jean-Michel Vallat
- Department of Neurology, CHU Limoges, Dupuytren University Hospital, 2 avenue Martin Luther King, 87042 Limoges, France; National Reference Center for 'Rare Peripheral Neuropathies', CHU Limoges, Dupuytren University Hospital, 2 avenue Martin Luther King, 87042 Limoges, France.
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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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Fehmi J, Scherer SS, Willison HJ, Rinaldi S. Nodes, paranodes and neuropathies. J Neurol Neurosurg Psychiatry 2018; 89:61-71. [PMID: 28819062 DOI: 10.1136/jnnp-2016-315480] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 06/28/2017] [Accepted: 06/29/2017] [Indexed: 12/13/2022]
Abstract
This review summarises recent evidence supporting the involvement of the specialised nodal and perinodal domains (the paranode and juxtaparanode) of myelinated axons in the pathology of acquired, inflammatory, peripheral neuropathies.The identification of new target antigens in the inflammatory neuropathies heralds a revolution in diagnosis, and has already begun to inform increasingly targeted and individualised therapies. Rapid progress in our basic understanding of the highly specialised nodal regions of peripheral nerves serves to strengthen the links between their unique microstructural identities, functions and pathologies. In this context, the detection of autoantibodies directed against nodal and perinodal targets is likely to be of increasing clinical importance. Antiganglioside antibodies have long been used in clinical practice as diagnostic serum biomarkers, and associate with specific clinical variants but not to the common forms of either acute or chronic demyelinating autoimmune neuropathy. It is now apparent that antibodies directed against several region-specific cell adhesion molecules, including neurofascin, contactin and contactin-associated protein, can be linked to phenotypically distinct peripheral neuropathies. Importantly, the immunological characteristics of these antibodies facilitate the prediction of treatment responsiveness.
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Affiliation(s)
- Janev Fehmi
- Department of Neurology, Southmead Hospital, Bristol, UK
| | - Steven S Scherer
- Department of Neurology, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Hugh J Willison
- Department of Neuroimmunology, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Simon Rinaldi
- Department of Clinical Neurosciences, West Wing, John Radcliffe Hospital, Oxford, UK
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Chaverneff F, Mierzwa A, Weinstock M, Ketcham M, Lang EJ, Rosenbluth J. Dysmyelination with preservation of transverse bands in a long-lived allele of the quaking mouse. J Comp Neurol 2014; 523:197-208. [PMID: 25185516 DOI: 10.1002/cne.23670] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 08/28/2014] [Accepted: 09/02/2014] [Indexed: 11/05/2022]
Abstract
The new mutant mouse shaking (shk) differs from other "myelin mutants" in having a more stable neurological impairment and a much longer lifespan. We have shown that transverse bands (TBs), the component of the paranodal junction (PNJ) that attaches the myelin sheath to the axon, are present in the shk central nervous system (CNS), in contrast to more severely affected mutants, in which TBs are absent or rare. We have proposed that TBs are the major determinant underlying shk neurological stability and longevity. Here we report that TBs are abundant not only in the shk CNS but also in its peripheral nervous system (PNS), which, as in other "myelin mutants", is not as severely dysmyelinated as the CNS but does display structural abnormalities likely to affect impulse propagation. In particular, myelin sheaths are thinner than normal, and some axonal segments lack myelin sheaths entirely. In addition, we establish that the shk mutation, previously localized to chromosome 17, is a quaking (qk) allele consisting of a 105-nucleotide insertion in the qk regulatory region that decreases qk transcription but does not extend to the Parkin and Parkin coregulated genes, which are affected in the qk allele. We conclude that: 1) dysmyelination is less severe in the shk PNS than in the CNS, but TBs, which are present in both locations, stabilize the PNJs and prevent the progressive neurological deficits seen in mutants lacking TBs; and 2) the insertional mutation in shk mice is sufficient to produce the characteristic neurological phenotype without involvement of the Parkin and Parkin coregulated genes.
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Affiliation(s)
- Florence Chaverneff
- Department of Neuroscience & Physiology, New York University School of Medicine, New York, New York, 10016
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