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Gemignani F, Percesepe A, Gualandi F, Allegri I, Bellanova MF, Nuredini A, Saccani E, Ambrosini E, Barili V, Uliana V. Charcot-Marie-Tooth Disease with Myelin Protein Zero Mutation Presenting as Painful, Predominant Small-Fiber Neuropathy. Int J Mol Sci 2024; 25:1654. [PMID: 38338934 PMCID: PMC10855578 DOI: 10.3390/ijms25031654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 01/16/2024] [Accepted: 01/20/2024] [Indexed: 02/12/2024] Open
Abstract
Charcot-Marie-Tooth disease (CMT) rarely presents with painful symptoms, which mainly occur in association with myelin protein zero (MPZ) gene mutations. We aimed to further characterize the features of painful neuropathic phenotypes in MPZ-related CMT. We report on a 58-year-old woman with a longstanding history of intermittent migrant pain and dysesthesias. Examination showed minimal clinical signs of neuropathy along with mild changes upon electroneurographic examination, consistent with an intermediate pattern, and small-fiber loss upon skin biopsy. Genetic testing identified the heterozygous variant p.Trp101Ter in MPZ. We identified another 20 CMT patients in the literature who presented with neuropathic pain as a main feature in association with MPZ mutations, mostly in the extracellular MPZ domain; the majority of these patients showed late onset (14/20), with motor-nerve-conduction velocities predominantly in the intermediate range (12/20). It is hypothesized that some MPZ mutations could manifest with, or predispose to, neuropathic pain. However, the mechanisms linking MPZ mutations and pain-generating nerve changes are unclear, as are the possible role of modifier factors. This peculiar CMT presentation may be diagnostically misleading, as it is suggestive of an acquired pain syndrome rather than of an inherited neuropathy.
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Affiliation(s)
- Franco Gemignani
- European Diagnostic Center, Polyclinic Dalla Rosa Prati, 43126 Parma, Italy
| | - Antonio Percesepe
- Medical Genetics Unit, Department of Medicine and Surgery, University of Parma, 43126 Parma, Italy
- Medical Genetics Unit, University Hospital of Parma, 43126 Parma, Italy
| | - Francesca Gualandi
- Medical Genetics Unit, Department of Mother and Child, Sant’Anna University Hospital of Ferrara, 44121 Ferrara, Italy
| | - Isabella Allegri
- Neurology Unit, Department of Specialized Medicine, University Hospital of Parma, 43126 Parma, Italy
| | - Maria Federica Bellanova
- Laboratory of Neuromuscular Histopathology, Department of Medicine and Surgery, University of Parma, 43126 Parma, Italy
| | - Andi Nuredini
- Neurology Unit, Department of Medicine and Surgery, University of Parma, 43126 Parma, Italy
| | - Elena Saccani
- Neurology Unit, Department of Specialized Medicine, University Hospital of Parma, 43126 Parma, Italy
| | - Enrico Ambrosini
- Medical Genetics Unit, University Hospital of Parma, 43126 Parma, Italy
| | - Valeria Barili
- Medical Genetics Unit, Department of Medicine and Surgery, University of Parma, 43126 Parma, Italy
| | - Vera Uliana
- Medical Genetics Unit, University Hospital of Parma, 43126 Parma, Italy
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Bremer J, Meinhardt A, Katona I, Senderek J, Kämmerer‐Gassler EK, Roos A, Ferbert A, Schröder JM, Nikolin S, Nolte K, Sellhaus B, Popzhelyazkova K, Tacke F, Schara‐Schmidt U, Neuen‐Jacob E, de Groote CC, de Jonghe P, Timmerman V, Baets J, Weis J. Myelin protein zero mutation-related hereditary neuropathies: Neuropathological insight from a new nerve biopsy cohort. Brain Pathol 2024; 34:e13200. [PMID: 37581289 PMCID: PMC10711263 DOI: 10.1111/bpa.13200] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 07/19/2023] [Indexed: 08/16/2023] Open
Abstract
Myelin protein zero (MPZ/P0) is a major structural protein of peripheral nerve myelin. Disease-associated variants in the MPZ gene cause a wide phenotypic spectrum of inherited peripheral neuropathies. Previous nerve biopsy studies showed evidence for subtype-specific morphological features. Here, we aimed at enhancing the understanding of these subtype-specific features and pathophysiological aspects of MPZ neuropathies. We examined archival material from two Central European centers and systematically determined genetic, clinical, and neuropathological features of 21 patients with MPZ mutations compared to 16 controls. Cases were grouped based on nerve conduction data into congenital hypomyelinating neuropathy (CHN; n = 2), demyelinating Charcot-Marie-Tooth (CMT type 1; n = 11), intermediate (CMTi; n = 3), and axonal CMT (type 2; n = 5). Six cases had combined muscle and nerve biopsies and one underwent autopsy. We detected four MPZ gene variants not previously described in patients with neuropathy. Light and electron microscopy of nerve biopsies confirmed fewer myelinated fibers, more onion bulbs and reduced regeneration in demyelinating CMT1 compared to CMT2/CMTi. In addition, we observed significantly more denervated Schwann cells, more collagen pockets, fewer unmyelinated axons per Schwann cell unit and a higher density of Schwann cell nuclei in CMT1 compared to CMT2/CMTi. CHN was characterized by basal lamina onion bulb formation, a further increase in Schwann cell density and hypomyelination. Most late onset axonal neuropathy patients showed microangiopathy. In the autopsy case, we observed prominent neuromatous hyperinnervation of the spinal meninges. In four of the six muscle biopsies, we found marked structural mitochondrial abnormalities. These results show that MPZ alterations not only affect myelinated nerve fibers, leading to either primarily demyelinating or axonal changes, but also affect non-myelinated nerve fibers. The autopsy case offers insight into spinal nerve root pathology in MPZ neuropathy. Finally, our data suggest a peculiar association of MPZ mutations with mitochondrial alterations in muscle.
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Affiliation(s)
- Juliane Bremer
- Institute of NeuropathologyRWTH Aachen University HospitalAachenGermany
| | - Axel Meinhardt
- Institute of NeuropathologyRWTH Aachen University HospitalAachenGermany
| | - Istvan Katona
- Institute of NeuropathologyRWTH Aachen University HospitalAachenGermany
| | - Jan Senderek
- Friedrich Baur Institute at the Department of NeurologyUniversity Hospital, LMU MunichMunichGermany
| | | | - Andreas Roos
- Institute of NeuropathologyRWTH Aachen University HospitalAachenGermany
- Department of NeuropaediatricsUniversity of EssenEssenGermany
| | | | | | - Stefan Nikolin
- Institute of NeuropathologyRWTH Aachen University HospitalAachenGermany
| | - Kay Nolte
- Institute of NeuropathologyRWTH Aachen University HospitalAachenGermany
| | - Bernd Sellhaus
- Institute of NeuropathologyRWTH Aachen University HospitalAachenGermany
| | | | - Frank Tacke
- Department of Hepatology and Gastroenterology, Charité—Universitätsmedizin BerlinCampus Virchow‐Klinikum (CVK) and Campus Charité Mitte (CCM)BerlinGermany
| | | | - Eva Neuen‐Jacob
- Department of NeuropathologyUniversity Hospital, Heinrich‐Heine University DüsseldorfDüsseldorfGermany
| | - Chantal Ceuterick de Groote
- Laboratory of Neuromuscular Pathology, Institute Born‐Bunge, and Translational Neurosciences, Faculty of MedicineUniversity of AntwerpBelgium
| | - Peter de Jonghe
- Laboratory of Neuromuscular Pathology, Institute Born‐Bunge, and Translational Neurosciences, Faculty of MedicineUniversity of AntwerpBelgium
- Department of NeurologyUniversity Hospital AntwerpAntwerpBelgium
| | - Vincent Timmerman
- Laboratory of Neuromuscular Pathology, Institute Born‐Bunge, and Translational Neurosciences, Faculty of MedicineUniversity of AntwerpBelgium
- Peripheral Neuropathy Research Group, Department of Biomedical SciencesUniversity of AntwerpAntwerpBelgium
| | - Jonathan Baets
- Laboratory of Neuromuscular Pathology, Institute Born‐Bunge, and Translational Neurosciences, Faculty of MedicineUniversity of AntwerpBelgium
- Department of NeurologyUniversity Hospital AntwerpAntwerpBelgium
| | - Joachim Weis
- Institute of NeuropathologyRWTH Aachen University HospitalAachenGermany
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Cook S, Hooser BN, Williams DC, Kortz G, Aleman M, Minor K, Koziol J, Friedenberg SG, Cullen JN, Shelton GD, Ekenstedt KJ. Canine models of Charcot-Marie-Tooth: MTMR2, MPZ, and SH3TC2 variants in golden retrievers with congenital hypomyelinating polyneuropathy. Neuromuscul Disord 2023; 33:677-691. [PMID: 37400349 PMCID: PMC10530471 DOI: 10.1016/j.nmd.2023.06.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 06/06/2023] [Accepted: 06/19/2023] [Indexed: 07/05/2023]
Abstract
Congenital hypomyelinating polyneuropathy (HPN) restricted to the peripheral nervous system was reported in 1989 in two Golden Retriever (GR) littermates. Recently, four additional cases of congenital HPN in young, unrelated GRs were diagnosed via neurological examination, electrodiagnostic evaluation, and peripheral nerve pathology. Whole-genome sequencing was performed on all four GRs, and variants from each dog were compared to variants found across >1,000 other dogs, all presumably unaffected with HPN. Likely causative variants were identified for each HPN-affected GR. Two cases shared a homozygous splice donor site variant in MTMR2, with a stop codon introduced within six codons following the inclusion of the intron. One case had a heterozygous MPZ isoleucine to threonine substitution. The last case had a homozygous SH3TC2 nonsense variant predicted to truncate approximately one-half of the protein. Haplotype analysis using 524 GR established the novelty of the identified variants. Each variant occurs within genes that are associated with the human Charcot-Marie-Tooth (CMT) group of heterogeneous diseases, affecting the peripheral nervous system. Testing a large GR population (n = >200) did not identify any dogs with these variants. Although these variants are rare within the general GR population, breeders should be cautious to avoid propagating these alleles.
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Affiliation(s)
- Shawna Cook
- Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA.
| | - Blair N Hooser
- Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA
| | - D Colette Williams
- The William R. Pritchard Veterinary Medical Teaching Hospital, University of California, Davis, Davis, CA, USA
| | - Gregg Kortz
- VCA Sacramento Veterinary Referral Center, Sacramento CA, USA
| | - Monica Aleman
- The William R. Pritchard Veterinary Medical Teaching Hospital, University of California, Davis, Davis, CA, USA
| | - Katie Minor
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN, USA
| | - Jennifer Koziol
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX, USA
| | - Steven G Friedenberg
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN, USA
| | - Jonah N Cullen
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN, USA
| | - G Diane Shelton
- Department of Pathology, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Kari J Ekenstedt
- Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA
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Fridman V, Sillau S, Bockhorst J, Smith K, Moroni I, Pagliano E, Pisciotta C, Piscosquito G, Laurá M, Muntoni F, Bacon C, Feely S, Grider T, Gutmann L, Shy R, Wilcox J, Herrmann DN, Li J, Ramchandren S, Sumner CJ, Lloyd TE, Day J, Siskind CE, Yum SW, Sadjadi R, Finkel RS, Scherer SS, Pareyson D, Reilly MM, Shy ME. Disease Progression in Charcot-Marie-Tooth Disease Related to MPZ Mutations: A Longitudinal Study. Ann Neurol 2023; 93:563-576. [PMID: 36203352 PMCID: PMC9977145 DOI: 10.1002/ana.26518] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 08/29/2022] [Accepted: 09/23/2022] [Indexed: 11/11/2022]
Abstract
OBJECTIVE The paucity of longitudinal natural history studies in MPZ neuropathy remains a barrier to clinical trials. We have completed a longitudinal natural history study in patients with MPZ neuropathies across 13 sites of the Inherited Neuropathies Consortium. METHODS Change in Charcot-Marie-Tooth Examination Score (CMTES) and Rasch modified CMTES (CMTES-R) were evaluated using longitudinal regression over a 5-year period in subjects with MPZ neuropathy. Data from 139 patients with MPZ neuropathy were examined. RESULTS The average baseline CMTES and CMTES-R were 10.84 (standard deviation [SD] = 6.0, range = 0-28) and 14.60 (SD = 7.56, range = 0-32), respectively. A mixed regression model showed significant change in CMTES at years 2-5 (mean change from baseline of 0.87 points at 2 years, p = 0.008). Subgroup analysis revealed greater change in CMTES at 2 years in subjects with axonal as compared to demyelinating neuropathy (mean change of 1.30 points [p = 0.016] vs 0.06 points [p = 0.889]). Patients with a moderate baseline neuropathy severity also showed more notable change, by estimate, than those with mild or severe neuropathy (mean 2-year change of 1.14 for baseline CMTES 8-14 [p = 0.025] vs -0.03 for baseline CMTES 0-7 [p = 0.958] and 0.25 for baseline CMTES ≥ 15 [p = 0.6897]). The progression in patients harboring specific MPZ mutations was highly variable. INTERPRETATION CMTES is sensitive to change over time in adult patients with axonal but not demyelinating forms of MPZ neuropathy. Change in CMTES was greatest in patients with moderate baseline disease severity. These findings will inform future clinical trials of MPZ neuropathies. ANN NEUROL 2023;93:563-576.
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Affiliation(s)
- Vera Fridman
- Department of Neurology, University of Colorado Denver, Aurora, Colorado, USA
| | - Stefan Sillau
- Department of Neurology, University of Colorado Denver, Aurora, Colorado, USA
| | - Jacob Bockhorst
- Department of Neurology, University of Colorado Denver, Aurora, Colorado, USA
| | - Kaitlin Smith
- Department of Neurology, University of Colorado Denver, Aurora, Colorado, USA
| | - Isabella Moroni
- Department of Child Neurology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Emanuela Pagliano
- Department of Child Neurology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Chiara Pisciotta
- Department of Clinical Neurosciences, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Guiseppe Piscosquito
- Department of Clinical Neurosciences, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
- Istituti Clinici Scientifici Maugeri, Neurorehabilitation Unit, Scientific Institute of Telese Terme (BN), Italy
| | - Matilde Laurá
- Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health & Great Ormond Street Hospital, London, UK
| | - Chelsea Bacon
- Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| | - Shawna Feely
- Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
- Department of Neurology, Wayne State University, Detroit, Michigan, USA
| | - Tiffany Grider
- Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| | - Laurie Gutmann
- Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| | - Rosemary Shy
- Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
- Department of Neurology, Wayne State University, Detroit, Michigan, USA
| | - Janel Wilcox
- Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| | - David N. Herrmann
- Department of Neurology, University of Rochester, Rochester, New York, USA
| | - Jun Li
- Department of Neurology, Wayne State University, Detroit, Michigan, USA
- Department of Neurology, Vanderbilt University, Nashville, Tennessee, USA
| | - Sindhu Ramchandren
- Department of Neurology, Wayne State University, Detroit, Michigan, USA
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
- PRA Health Sciences, Raleigh, North Carolina, USA
| | - Charlotte J. Sumner
- Departments of Neurology and Neuroscience, John Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Thomas E. Lloyd
- Departments of Neurology and Neuroscience, John Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - John Day
- Department of Neurology, Stanford University, Stanford, California, USA
| | - Carly E. Siskind
- Department of Neurology, Stanford University, Stanford, California, USA
| | - Sabrina W. Yum
- Department of Neurology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Neurology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Reza Sadjadi
- Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Richard S. Finkel
- Department of Neurology, Nemours Children’s Hospital, Orlando, Florida, USA
| | - Steven S. Scherer
- Department of Neurology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Davide Pareyson
- Department of Clinical Neurosciences, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Mary M Reilly
- Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Michael E. Shy
- Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
- Department of Neurology, Wayne State University, Detroit, Michigan, USA
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A new mouse model of Charcot-Marie-Tooth 2J neuropathy replicates human axonopathy and suggest alteration in axo-glia communication. PLoS Genet 2022; 18:e1010477. [DOI: 10.1371/journal.pgen.1010477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 11/29/2022] [Accepted: 10/13/2022] [Indexed: 11/10/2022] Open
Abstract
Myelin is essential for rapid nerve impulse propagation and axon protection. Accordingly, defects in myelination or myelin maintenance lead to secondary axonal damage and subsequent degeneration. Studies utilizing genetic (CNPase-, MAG-, and PLP-null mice) and naturally occurring neuropathy models suggest that myelinating glia also support axons independently from myelin. Myelin protein zero (MPZ or P0), which is expressed only by Schwann cells, is critical for myelin formation and maintenance in the peripheral nervous system. Many mutations in MPZ are associated with demyelinating neuropathies (Charcot-Marie-Tooth disease type 1B [CMT1B]). Surprisingly, the substitution of threonine by methionine at position 124 of P0 (P0T124M) causes axonal neuropathy (CMT2J) with little to no myelin damage. This disease provides an excellent paradigm to understand how myelinating glia support axons independently from myelin. To study this, we generated targeted knock-in MpzT124M mutant mice, a genetically authentic model of T124M-CMT2J neuropathy. Similar to patients, these mice develop axonopathy between 2 and 12 months of age, characterized by impaired motor performance, normal nerve conduction velocities but reduced compound motor action potential amplitudes, and axonal damage with only minor compact myelin modifications. Mechanistically, we detected metabolic changes that could lead to axonal degeneration, and prominent alterations in non-compact myelin domains such as paranodes, Schmidt-Lanterman incisures, and gap junctions, implicated in Schwann cell-axon communication and axonal metabolic support. Finally, we document perturbed mitochondrial size and distribution along MpzT124M axons suggesting altered axonal transport. Our data suggest that Schwann cells in P0T124M mutant mice cannot provide axons with sufficient trophic support, leading to reduced ATP biosynthesis and axonopathy. In conclusion, the MpzT124M mouse model faithfully reproduces the human neuropathy and represents a unique tool for identifying the molecular basis for glial support of axons.
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Veneri FA, Prada V, Mastrangelo R, Ferri C, Nobbio L, Passalacqua M, Milanesi M, Bianchi F, Del Carro U, Vallat JM, Duong P, Svaren J, Schenone A, Grandis M, D’Antonio M. A novel mouse model of CMT1B identifies hyperglycosylation as a new pathogenetic mechanism. Hum Mol Genet 2022; 31:4255-4274. [PMID: 35908287 PMCID: PMC9759335 DOI: 10.1093/hmg/ddac170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 07/19/2022] [Accepted: 07/20/2022] [Indexed: 01/21/2023] Open
Abstract
Mutations in the Myelin Protein Zero gene (MPZ), encoding P0, the major structural glycoprotein of peripheral nerve myelin, are the cause of Charcot-Marie-Tooth (CMT) type 1B neuropathy, and most P0 mutations appear to act through gain-of-function mechanisms. Here, we investigated how misglycosylation, a pathomechanism encompassing several genetic disorders, may affect P0 function. Using in vitro assays, we showed that gain of glycosylation is more damaging for P0 trafficking and functionality as compared with a loss of glycosylation. Hence, we generated, via CRISPR/Cas9, a mouse model carrying the MPZD61N mutation, predicted to generate a new N-glycosylation site in P0. In humans, MPZD61N causes a severe early-onset form of CMT1B, suggesting that hyperglycosylation may interfere with myelin formation, leading to pathology. We show here that MPZD61N/+ mice develop a tremor as early as P15 which worsens with age and correlates with a significant motor impairment, reduced muscular strength and substantial alterations in neurophysiology. The pathological analysis confirmed a dysmyelinating phenotype characterized by diffuse hypomyelination and focal hypermyelination. We find that the mutant P0D61N does not cause significant endoplasmic reticulum stress, a common pathomechanism in CMT1B, but is properly trafficked to myelin where it causes myelin uncompaction. Finally, we show that myelinating dorsal root ganglia cultures from MPZD61N mice replicate some of the abnormalities seen in vivo, suggesting that they may represent a valuable tool to investigate therapeutic approaches. Collectively, our data indicate that the MPZD61N/+ mouse represents an authentic model of severe CMT1B affirming gain-of-glycosylation in P0 as a novel pathomechanism of disease.
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Affiliation(s)
- Francesca A Veneri
- Biology of Myelin Unit, Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, 20132 Milan, Italy,Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genova, IRCCS AOU San Martino-IST, 16132 Genova, Italy
| | - Valeria Prada
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genova, IRCCS AOU San Martino-IST, 16132 Genova, Italy
| | - Rosa Mastrangelo
- Biology of Myelin Unit, Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, 20132 Milan, Italy
| | - Cinzia Ferri
- Biology of Myelin Unit, Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, 20132 Milan, Italy
| | - Lucilla Nobbio
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genova, IRCCS AOU San Martino-IST, 16132 Genova, Italy
| | - Mario Passalacqua
- Department of Experimental Medicine, University of Genova, 16132 Genova, Italy
| | - Maria Milanesi
- Experimental Oncology and Immunology, Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy
| | - Francesca Bianchi
- Movement Disorders Unit, Division of Neuroscience, IRCCS Ospedale San Raffaele, 20132 Milan, Italy
| | - Ubaldo Del Carro
- Movement Disorders Unit, Division of Neuroscience, IRCCS Ospedale San Raffaele, 20132 Milan, Italy
| | - Jean-Michel Vallat
- Department and Laboratory of Neurology, National Reference Center for ‘Rare Peripheral Neuropathies’, University Hospital of Limoges (CHU Limoges), Dupuytren Hospital, 87000 Limoges, France
| | - Phu Duong
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin–Madison, Madison, WI 53706, USA
| | - John Svaren
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin–Madison, Madison, WI 53706, USA
| | - Angelo Schenone
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genova, IRCCS AOU San Martino-IST, 16132 Genova, Italy,Department of Neurology, IRCCS Ospedale Policlinico San Martino, 16132 Genova, Italy
| | - Marina Grandis
- To whom correspondence should be addressed at: Department of Neurology, IRCCS Ospedale Policlinico San Martino, Largo Daneo 3, 16132 Genova, Italy. Tel: +39 010 3537562; (M.G.); San Raffaele Scientific Institute, DIBIT, via Olgettina 58, 20132 Milan, Italy. Tel: +39 02 26435307; (M.D.)
| | - Maurizio D’Antonio
- To whom correspondence should be addressed at: Department of Neurology, IRCCS Ospedale Policlinico San Martino, Largo Daneo 3, 16132 Genova, Italy. Tel: +39 010 3537562; (M.G.); San Raffaele Scientific Institute, DIBIT, via Olgettina 58, 20132 Milan, Italy. Tel: +39 02 26435307; (M.D.)
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7
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Bai Y, Treins C, Volpi VG, Scapin C, Ferri C, Mastrangelo R, Touvier T, Florio F, Bianchi F, Del Carro U, Baas FF, Wang D, Miniou P, Guedat P, Shy ME, D'Antonio M. Treatment with IFB-088 Improves Neuropathy in CMT1A and CMT1B Mice. Mol Neurobiol 2022; 59:4159-4178. [PMID: 35501630 PMCID: PMC9167212 DOI: 10.1007/s12035-022-02838-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 04/09/2022] [Indexed: 11/24/2022]
Abstract
Charcot-Marie-Tooth disease type 1A (CMT1A), caused by duplication of the peripheral myelin protein 22 (PMP22) gene, and CMT1B, caused by mutations in myelin protein zero (MPZ) gene, are the two most common forms of demyelinating CMT (CMT1), and no treatments are available for either. Prior studies of the MpzSer63del mouse model of CMT1B have demonstrated that protein misfolding, endoplasmic reticulum (ER) retention and activation of the unfolded protein response (UPR) contributed to the neuropathy. Heterozygous patients with an arginine to cysteine mutation in MPZ (MPZR98C) develop a severe infantile form of CMT1B which is modelled by MpzR98C/ + mice that also show ER stress and an activated UPR. C3-PMP22 mice are considered to effectively model CMT1A. Altered proteostasis, ER stress and activation of the UPR have been demonstrated in mice carrying Pmp22 mutations. To determine whether enabling the ER stress/UPR and readjusting protein homeostasis would effectively treat these models of CMT1B and CMT1A, we administered Sephin1/IFB-088/icerguestat, a UPR modulator which showed efficacy in the MpzS63del model of CMT1B, to heterozygous MpzR98C and C3-PMP22 mice. Mice were analysed by behavioural, neurophysiological, morphological and biochemical measures. Both MpzR98C/ + and C3-PMP22 mice improved in motor function and neurophysiology. Myelination, as demonstrated by g-ratios and myelin thickness, improved in CMT1B and CMT1A mice and markers of UPR activation returned towards wild-type values. Taken together, our results demonstrate the capability of IFB-088 to treat a second mouse model of CMT1B and a mouse model of CMT1A, the most common form of CMT. Given the recent benefits of IFB-088 treatment in amyotrophic lateral sclerosis and multiple sclerosis animal models, these data demonstrate its potential in managing UPR and ER stress for multiple mutations in CMT1 as well as in other neurodegenerative diseases.
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Affiliation(s)
- Yunhong Bai
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | | | - Vera G Volpi
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute DIBIT, 20132, Milan, Italy
| | - Cristina Scapin
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute DIBIT, 20132, Milan, Italy
| | - Cinzia Ferri
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute DIBIT, 20132, Milan, Italy
| | - Rosa Mastrangelo
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute DIBIT, 20132, Milan, Italy
| | - Thierry Touvier
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute DIBIT, 20132, Milan, Italy
| | - Francesca Florio
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute DIBIT, 20132, Milan, Italy
| | - Francesca Bianchi
- Division of Neuroscience, San Raffaele Scientific Institute DIBIT, 20132, Milan, Italy
| | - Ubaldo Del Carro
- Division of Neuroscience, San Raffaele Scientific Institute DIBIT, 20132, Milan, Italy
| | - Frank F Baas
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - David Wang
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | | | | | - Michael E Shy
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Maurizio D'Antonio
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute DIBIT, 20132, Milan, Italy.
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8
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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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9
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Animal Models as a Tool to Design Therapeutical Strategies for CMT-like Hereditary Neuropathies. Brain Sci 2021; 11:brainsci11091237. [PMID: 34573256 PMCID: PMC8465478 DOI: 10.3390/brainsci11091237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 09/05/2021] [Accepted: 09/07/2021] [Indexed: 02/07/2023] Open
Abstract
Since ancient times, animal models have provided fundamental information in medical knowledge. This also applies for discoveries in the field of inherited peripheral neuropathies (IPNs), where they have been instrumental for our understanding of nerve development, pathogenesis of neuropathy, molecules and pathways involved and to design potential therapies. In this review, we briefly describe how animal models have been used in ancient medicine until the use of rodents as the prevalent model in present times. We then travel along different examples of how rodents have been used to improve our understanding of IPNs. We do not intend to describe all discoveries and animal models developed for IPNs, but just to touch on a few arbitrary and paradigmatic examples, taken from our direct experience or from literature. The idea is to show how strategies have been developed to finally arrive to possible treatments for IPNs.
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10
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Subréville M, Bonello-Palot N, Yahiaoui D, Beloribi-Djefaflia S, Fernandes S, Stojkovic T, Cassereau J, Péréon Y, Echaniz-Laguna A, Violleau MH, Soulages A, Louis SL, Masingue M, Magot A, Delmont E, Sacconi S, Adams D, Labeyrie C, Genestet S, Noury JB, Chanson JB, Lévy N, Juntas-Morales R, Tard C, Sole G, Attarian S. Genotype-phenotype correlation in French patients with myelin protein zero gene-related inherited neuropathy. Eur J Neurol 2021; 28:2913-2921. [PMID: 34060176 DOI: 10.1111/ene.14948] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 04/23/2021] [Accepted: 05/19/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND AND PURPOSE Preparations for clinical trials of unfolded protein response (UPR) inhibitors (such as Sephin1) that target the upregulated UPR in patients with Charcot-Marie-Tooth disease (CMT) carrying MPZ mutations are currently underway. The inclusion criteria for these trials are still being formulated. Our objective was to characterize the relation between genotypes and phenotypes in patients with CMT caused by MPZ mutations, and to refine the inclusion criteria for future trials. METHODS Clinical and neurophysiological data of CMT patients with MPZ mutations were retrospectively collected at 11 French reference centers. RESULTS Forty-four mutations in MPZ were identified in 91 patients from 61 families. There was considerable heterogeneity. The same mutation was found to cause either axonal or demyelinating neuropathy. Three groups were identified according to the age at disease onset. CMT Examination Score (CMTES) tended to be higher in the early (≤22 years) and adult (23-47 years) onset groups (mean CMTESv2 = 10.4 and 10.0, respectively) than in the late onset group (>47 years, mean CMTESv2 = 8.6, p = 0.47). There was a significant positive correlation between CMTESv2 and the age of patients in Groups I (p = 0.027) and II (p = 0.023), indicating that clinical severity progressed with age in these patients. CONCLUSIONS To optimize the selection of CMT patients carrying MPZ mutations for the upcoming trials, inclusion criteria should take into account the pathophysiology of the disease (upregulated UPR). Recruited patients should have a mild to moderate disease severity and a disease onset at between 18 and 50 years, as these patients exhibit significant disease progression over time.
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Affiliation(s)
- Marie Subréville
- Reference Center for Neuromuscular Disorders and ALS, APHM, CHU La Timone, Marseille, France
| | | | - Douniazed Yahiaoui
- Reference Center for Neuromuscular Disorders and ALS, APHM, CHU La Timone, Marseille, France
| | | | - Sara Fernandes
- CEReSS-Health Service Research and Quality of Life Center, Aix-Marseille University, Marseille, France
| | - Tanya Stojkovic
- Reference Center for Neuromuscular Diseases North/East/Ile de France, Hôpital Pitié-Salpêtrière, AP-HP, Paris, France
| | - Julien Cassereau
- Reference Center for Neuromuscular Disorders AOC and National Reference Center for Neurogenetic Diseases, Angers University Hospital, Angers, France
| | - Yann Péréon
- Department of Clinical Neurophysiology, Reference Center for NMD, CHU Nantes, Nantes, France
| | - Andoni Echaniz-Laguna
- Department of Neurology, APHP, CHU de Bicêtre, Le Kremlin-Bicêtre, France.,French National Reference Center for Rare Neuropathies, Le Kremlin-Bicêtre, France.,Inserm U1195 and Paris-Sud University, Le Kremlin-Bicêtre, France
| | | | - Antoine Soulages
- Reference Center for Neuromuscular Disorders AOC, CHU de Bordeaux, Bordeaux, France
| | - Sarah Léonard Louis
- Reference Center for Neuromuscular Diseases North/East/Ile de France, Hôpital Pitié-Salpêtrière, AP-HP, Paris, France
| | - Marion Masingue
- Reference Center for Neuromuscular Diseases North/East/Ile de France, Hôpital Pitié-Salpêtrière, AP-HP, Paris, France
| | - Armelle Magot
- Department of Clinical Neurophysiology, Reference Center for NMD, CHU Nantes, Nantes, France
| | - Emilien Delmont
- Reference Center for Neuromuscular Disorders and ALS, APHM, CHU La Timone, Marseille, France
| | - Sabrina Sacconi
- Peripheral Nervous System Service, Muscle et SLA, Centre Hospitalier Universitaire de Nice, Université Côte d'Azur, Nice, France
| | - David Adams
- Department of Neurology, APHP, CHU de Bicêtre, Le Kremlin-Bicêtre, France
| | - Céline Labeyrie
- Department of Neurology, APHP, CHU de Bicêtre, Le Kremlin-Bicêtre, France
| | | | | | - Jean-Baptiste Chanson
- Department of Neurology, Hôpital de Hautepierre, CHU de Strasbourg, Strasbourg, France
| | - Nicolas Lévy
- Marseille Medical Genetics, Aix-Marseille University-Inserm UMR 1251, Marseille, France
| | - Raul Juntas-Morales
- Reference Center for Neuromuscular Disorders AOC, Department of Neurology, CHU Montpellier, Montpellier, France
| | - Céline Tard
- Inserm U1171, Department of Neurology, Reference Center for Neuromuscular Diseases North/East/Ile de France, CHU Lille, Lille University, Lille, France
| | - Guilhem Sole
- Reference Center for Neuromuscular Disorders AOC, CHU de Bordeaux, Bordeaux, France
| | - Shahram Attarian
- Reference Center for Neuromuscular Disorders and ALS, APHM, CHU La Timone, Marseille, France.,Marseille Medical Genetics, Aix-Marseille University-Inserm UMR 1251, Marseille, France
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11
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Howard P, Feely SME, Grider T, Bacha A, Scarlato M, Fazio R, Quattrini A, Shy ME, Previtali SC. Loss of function MPZ mutation causes milder CMT1B neuropathy. J Peripher Nerv Syst 2021; 26:177-183. [PMID: 33960567 DOI: 10.1111/jns.12452] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 04/29/2021] [Accepted: 05/01/2021] [Indexed: 02/06/2023]
Abstract
Mutations in Myelin Protein Zero (MPZ) cause CMT1B, the second leading cause of CMT1. Many of the >200 mutations cause neuropathy through a toxic gain of function by the mutant protein such as ER retention, activation of the Unfolded Protein Response (UPR) or disruption of myelin compaction. While there is extensive literature on the loss of function consequences of MPZ in heterozygous Mpz +/- null mice, there is little known of the consequences of MPZ haploinsufficiency in humans. We identified six patients from different families with p.Tyr68Ter or p.Asp104fs heterozygous mutations of MPZ that are predicted to cause a premature termination and nonsense mediated decay of the mutant allele. Five patients were evaluated in Milan and one in Iowa City; all should be haploinsufficient for MPZ. Patients were evaluated clinically and by electrophysiology. Sensory ataxia dominated the clinical presentation with only mild weakness present in five of the six patients. Symptoms presented in adulthood in all patients and only one individual had a CMTNSv2 >5. Deep tendon reflexes were absent in all patients. Patients with likely MPZ loss of function due to mutations that cause haplodeficiency in MPZ have a mild, predominantly large fiber sensory neuropathy that serves as a human equivalent to the neuropathy observed in heterozygous Mpz null mice. Successful therapeutic approaches in treating Mpz deficient mice may be candidates for trials in these and similar patients.
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Affiliation(s)
- Paige Howard
- Roy and Lucille Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | | | - Tiffany Grider
- University of Iowa Healthcare Neurology, Iowa City, Iowa, USA
| | - Alexa Bacha
- Roy and Lucille Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Marina Scarlato
- Institute of Experimental Neurology (InSpe) and Division of Neuroscience, IRCCS Ospedale San Raffaele, Milano, Italy
| | - Raffaella Fazio
- Institute of Experimental Neurology (InSpe) and Division of Neuroscience, IRCCS Ospedale San Raffaele, Milano, Italy
| | - Angelo Quattrini
- Institute of Experimental Neurology (InSpe) and Division of Neuroscience, IRCCS Ospedale San Raffaele, Milano, Italy
| | - Michael E Shy
- Roy and Lucille Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Stefano C Previtali
- Institute of Experimental Neurology (InSpe) and Division of Neuroscience, IRCCS Ospedale San Raffaele, Milano, Italy
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12
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How Does Protein Zero Assemble Compact Myelin? Cells 2020; 9:cells9081832. [PMID: 32759708 PMCID: PMC7465998 DOI: 10.3390/cells9081832] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 07/21/2020] [Accepted: 07/30/2020] [Indexed: 02/06/2023] Open
Abstract
Myelin protein zero (P0), a type I transmembrane protein, is the most abundant protein in peripheral nervous system (PNS) myelin—the lipid-rich, periodic structure of membrane pairs that concentrically encloses long axonal segments. Schwann cells, the myelinating glia of the PNS, express P0 throughout their development until the formation of mature myelin. In the intramyelinic compartment, the immunoglobulin-like domain of P0 bridges apposing membranes via homophilic adhesion, forming, as revealed by electron microscopy, the electron-dense, double “intraperiod line” that is split by a narrow, electron-lucent space corresponding to the extracellular space between membrane pairs. The C-terminal tail of P0 adheres apposing membranes together in the narrow cytoplasmic compartment of compact myelin, much like myelin basic protein (MBP). In mouse models, the absence of P0, unlike that of MBP or P2, severely disturbs myelination. Therefore, P0 is the executive molecule of PNS myelin maturation. How and when P0 is trafficked and modified to enable myelin compaction, and how mutations that give rise to incurable peripheral neuropathies alter the function of P0, are currently open questions. The potential mechanisms of P0 function in myelination are discussed, providing a foundation for the understanding of mature myelin development and how it derails in peripheral neuropathies.
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13
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Mutation update for myelin protein zero-related neuropathies and the increasing role of variants causing a late-onset phenotype. J Neurol 2019; 266:2629-2645. [DOI: 10.1007/s00415-019-09453-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 06/21/2019] [Accepted: 06/26/2019] [Indexed: 01/18/2023]
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14
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Chang EH, Mo WM, Doo HM, Lee JS, Park HT, Choi BO, Hong YB. Aminosalicylic acid reduces ER stress and Schwann cell death induced by MPZ mutations. Int J Mol Med 2019; 44:125-134. [PMID: 31059078 PMCID: PMC6559330 DOI: 10.3892/ijmm.2019.4178] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 04/25/2019] [Indexed: 12/26/2022] Open
Abstract
Mutations in myelin protein zero (MPZ) cause inherited peripheral neuropathies, including Charcot‑Marie‑Tooth disease (CMT) and Dejerine‑Sottas neuropathy. Mutant MPZ proteins have previously been reported to cause CMT via enhanced endoplasmic reticulum (ER) stress and Schwann cell (SC) death, although the pathological mechanisms have not yet been elucidated. In this study, we generated an in vitro model of rat SCs expressing mutant MPZ (MPZ V169fs or R98C) proteins and validated the increase in cell death and ER stress induced by the overexpression of the MPZ mutants. Using this model, we examined the efficacy of 3 different aminosalicylic acids (ASAs; 4‑ASA, sodium 4‑ASA and 5‑ASA) in alleviating pathological phenotypes. FACS analysis indicated that the number of apoptotic rat SCs, RT4 cells, induced by mutant MPZ overexpression was significantly reduced following treatment with each ASA. In particular, treatment with 4‑ASA reduced the levels of ER stress markers in RT4 cells induced by V169fs MPZ mutant overexpression and relieved the retention of V169fs mutant proteins in the ER. Additionally, the level of an apoptotic signal mediator (p‑JNK) was only decreased in the RT4 cells expressing R98C MPZ mutant protein following treatment with 4‑ASA. Although 4‑ASA is known as a free radical scavenger, treatment with 4‑ASA in the in vitro model did not moderate the level of reactive oxygen species, which was elevated by the expression of mutant MPZ proteins. On the whole, the findings of this study indicate that treatment with 4‑ASA reduced the ER stress and SC death caused by 2 different MPZ mutants and suggest that ASA may be a potential therapeutic agent for CMT.
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Affiliation(s)
- Eun Hyuk Chang
- Samsung Biomedical Research Institute, Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., Seoul 06351, Republic of Korea
| | - Won Min Mo
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Republic of Korea
| | - Hyun Myung Doo
- Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul 03063, Republic of Korea
| | - Ji-Su Lee
- Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul 03063, Republic of Korea
| | - Hwan Tae Park
- Department of Physiology, College of Medicine, Dong‑A University, Busan 49201, Republic of Korea
| | - Byung-Ok Choi
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Republic of Korea
| | - Young Bin Hong
- Department of Biochemistry, College of Medicine, Dong‑A University, Busan 49201, Republic of Korea
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15
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Murakami T, Sunada Y. Schwann Cell and the Pathogenesis of Charcot–Marie–Tooth Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1190:301-321. [DOI: 10.1007/978-981-32-9636-7_19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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16
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Yu T, Liang L, Zhao X, Yin Y. Structural and biochemical studies of the extracellular domain of Myelin protein zero-like protein 1. Biochem Biophys Res Commun 2018; 506:883-890. [PMID: 30392906 DOI: 10.1016/j.bbrc.2018.10.161] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 10/26/2018] [Indexed: 01/17/2023]
Abstract
Myelin protein zero-like protein 1 (MPZL1) is a member of the immunoglobulin superfamily, and is also a receptor of concanavalin A (ConA). MPZL1 is upregulated in hepatocellular carcinoma (HCC) and accelerates migration of HCC cells. However, function of MPZL1 as a receptor of ConA and its role in HCC development are largely unknown. To elucidate the functional basis, we have determined the crystal structure of the extracellular domain of MPZL1 at 2.7 Å resolution. Overall, it folds like a typical immunoglobulin variable-like domain that is much like MPZ. Unexpectedly, we found Asn50 is a unique glycosylation site and the glycosylation mediates its interaction with ConA. Furthermore, we also found that MPZL1 exists as a homodimer in the crystal, in which hydrogen bonds between Ser86 and Val145 play an important role. Our results demonstrate that glycosylation of Asn50 is essential for its function as a receptor of ConA. We propose that dimerization of MPZL1 participates in control of its signal transmission in cell adhesion.
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Affiliation(s)
- Tianshu Yu
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Ling Liang
- Department of Biophysics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China; Institute of Systems Biomedicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Xuyang Zhao
- Institute of Systems Biomedicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Yuxin Yin
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China; Institute of Systems Biomedicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China; Department of Pathology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China.
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17
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Bai Y, Wu X, Brennan KM, Wang DS, D'Antonio M, Moran J, Svaren J, Shy ME. Myelin protein zero mutations and the unfolded protein response in Charcot Marie Tooth disease type 1B. Ann Clin Transl Neurol 2018; 5:445-455. [PMID: 29687021 PMCID: PMC5899917 DOI: 10.1002/acn3.543] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 01/24/2018] [Accepted: 01/29/2018] [Indexed: 12/13/2022] Open
Abstract
Objective To determine the prevalence of MPZ mutations that cause Charcot Marie Tooth neuropathy type 1B (CMT1B) and activate the unfolded protein Response (UPR). Background CMT1B is caused by >200 heterozygous mutations in MPZ, the major protein in peripheral nerve myelin. Mutations Ser63del MPZ and Arg98Cys MPZ cause the mutant protein to be retained in the ER and activate the generally adaptive UPR. Treatments that modulate UPR activation have improved cellular and rodent models of CMT1B raising the possibility that other MPZ mutations that activate the UPR would also respond favorably to similar treatment. The prevalence of MPZ mutations that activate the UPR is unknown. Methods We developed a dual luciferase reporter assay of Xbp1 splicing using stably transfected RT4 Schwann cells to assay the ability of cDNA constructs bearing 46 distinct MPZ mutations to activate the UPR. Constructs also carried an HA tag to permit detection of ER retention of mutant proteins. UPR activation and ER retention were correlated with clinical phenotypes. Results Eighteen mutations demonstrated ER retention and UPR activation to a similar degree as Ser63del and Arg98Cys MPZ. Thirty‐five of the mutations activated the UPR > 1.5 fold compared to that of wild‐type MPZ. Correlation was high between firefly and Nano‐luciferase reporters and between both reporters and ER localization. UPR activity did not correlate with clinical onset or severity. Conclusion Many CMT1B causing mutations activate the UPR and may be susceptible to therapeutic efforts to facilitate UPR function.
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Affiliation(s)
- Yunhong Bai
- Department of Neurology, Neuromuscular and Neurogenetics Divisions University of Iowa Hospitals and Clinics Iowa City Iowa
| | - Xingyao Wu
- Department of Neurology, Neuromuscular and Neurogenetics Divisions University of Iowa Hospitals and Clinics Iowa City Iowa
| | - Kathryn M Brennan
- Department of Neurology, Neuromuscular and Neurogenetics Divisions University of Iowa Hospitals and Clinics Iowa City Iowa
| | - David S Wang
- Department of Neurology, Neuromuscular and Neurogenetics Divisions University of Iowa Hospitals and Clinics Iowa City Iowa
| | - Maurizio D'Antonio
- Biology of Myelin Unit San Raffaele Scientific Institute DIBIT Milano Italy
| | - John Moran
- Waisman Center University of Wisconsin Madison Wisconsin.,Department of Comparative Biosciences University of Wisconsin Madison Wisconsin
| | - John Svaren
- Waisman Center University of Wisconsin Madison Wisconsin.,Department of Comparative Biosciences University of Wisconsin Madison Wisconsin
| | - Michael E Shy
- Department of Neurology, Neuromuscular and Neurogenetics Divisions University of Iowa Hospitals and Clinics Iowa City Iowa
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18
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Volpi VG, Touvier T, D'Antonio M. Endoplasmic Reticulum Protein Quality Control Failure in Myelin Disorders. Front Mol Neurosci 2017; 9:162. [PMID: 28101003 PMCID: PMC5209374 DOI: 10.3389/fnmol.2016.00162] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 12/16/2016] [Indexed: 12/24/2022] Open
Abstract
Reaching the correct three-dimensional structure is crucial for the proper function of a protein. The endoplasmic reticulum (ER) is the organelle where secreted and transmembrane proteins are synthesized and folded. To guarantee high fidelity of protein synthesis and maturation in the ER, cells have evolved ER-protein quality control (ERQC) systems, which assist protein folding and promptly degrade aberrant gene products. Only correctly folded proteins that pass ERQC checkpoints are allowed to exit the ER and reach their final destination. Misfolded glycoproteins are detected and targeted for degradation by the proteasome in a process known as endoplasmic reticulum-associated degradation (ERAD). The excess of unstructured proteins in the ER triggers an adaptive signal transduction pathway, called unfolded protein response (UPR), which in turn potentiates ERQC activities in order to reduce the levels of aberrant molecules. When the situation cannot be restored, the UPR drives cells to apoptosis. Myelin-forming cells of the central and peripheral nervous system (oligodendrocytes and Schwann cells) synthesize a large amount of myelin proteins and lipids and therefore are particularly susceptible to ERQC failure. Indeed, deficits in ERQC and activation of ER stress/UPR have been implicated in several myelin disorders, such as Pelizaeus-Merzbacher and Krabbe leucodystrophies, vanishing white matter disease and Charcot-Marie-Tooth neuropathies. Here we discuss recent evidence underlying the importance of proper ERQC functions in genetic disorders of myelinating glia.
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Affiliation(s)
- Vera G Volpi
- Biology of Myelin Unit, Division of Genetics and Cell Biology, San Raffaele Scientific Institute, DIBIT Milan, Italy
| | - Thierry Touvier
- Biology of Myelin Unit, Division of Genetics and Cell Biology, San Raffaele Scientific Institute, DIBIT Milan, Italy
| | - Maurizio D'Antonio
- Biology of Myelin Unit, Division of Genetics and Cell Biology, San Raffaele Scientific Institute, DIBIT Milan, Italy
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19
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Yang Y, Liang M, Shi Y. Retracted Article: Self-association of L-periaxin occurs via its acidic domain and NLS2/NLS3, and affects its trafficking in RSC96 cells. RSC Adv 2017. [DOI: 10.1039/c7ra06853k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Periaxin (PRX) protein was first identified in myelinating Schwann cells through the screening of cytoskeleton-associated proteins in peripheral nerve myelination.
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Affiliation(s)
- Yenan Yang
- Institute of Biotechnology
- Key Laboratory of Chemical Biology
- Molecular Engineering of Ministry of Education
- Shanxi University
- Taiyuan 030006
| | - Min Liang
- Institute of Biotechnology
- Key Laboratory of Chemical Biology
- Molecular Engineering of Ministry of Education
- Shanxi University
- Taiyuan 030006
| | - Yawei Shi
- Institute of Biotechnology
- Key Laboratory of Chemical Biology
- Molecular Engineering of Ministry of Education
- Shanxi University
- Taiyuan 030006
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20
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La Padula V, Staszewski O, Nestel S, Busch H, Boerries M, Roussa E, Prinz M, Krieglstein K. HSPB3 protein is expressed in motoneurons and induces their survival after lesion-induced degeneration. Exp Neurol 2016; 286:40-49. [PMID: 27567740 DOI: 10.1016/j.expneurol.2016.08.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 07/08/2016] [Accepted: 08/23/2016] [Indexed: 02/06/2023]
Abstract
The human small heat shock proteins (HSPBs) form a family of molecular chaperones comprising ten members (HSPB1-HSPB10), whose functions span from protein quality control to cytoskeletal dynamics and cell death control. Mutations in HSPBs can lead to human disease and particularly point mutations in HSPB1 and HSPB8 are known to lead to peripheral neuropathies. Recently, a missense mutation (R7S) in yet another member of this family, HSPB3, was found to cause an axonal motor neuropathy (distal hereditary motor neuropathy type 2C, dHMN2C). Until now, HSPB3 protein localization and function in motoneurons (MNs) have not yet been characterized. Therefore, we studied the endogenous HSPB3 protein distribution in the spinal cords of chicken and mouse embryos and in the postnatal nervous system (central and peripheral) of chicken, mouse and human. We further investigated the impact of wild-type and mutated HSPB3 on MN cell death via overexpressing these genes in ovo in an avian model of MN degeneration, the limb-bud removal. Altogether, our findings represent a first step for a better understanding of the cellular and molecular mechanisms leading to dHMN2C.
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Affiliation(s)
- Veronica La Padula
- Institute of Anatomy and Cell Biology, Department of Molecular Embryology, Albertstraße 17, 79104 Freiburg, Germany.
| | - Ori Staszewski
- Institute of Neuropathology, Neurozentrum, Breisacherstraße 64, 79106 Freiburg, Germany.
| | - Sigrun Nestel
- Institute of Anatomy and Cell Biology, Department of Neuroanatomy, Albertstraße 17, 79104 Freiburg, Germany
| | - Hauke Busch
- Systems Biology of the Cellular Microenvironment Group, Institute of Molecular Medicine and Cell Research, University of Freiburg, Germany; German Cancer Consortium (DKTK), Freiburg, Germany; German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Melanie Boerries
- Systems Biology of the Cellular Microenvironment Group, Institute of Molecular Medicine and Cell Research, University of Freiburg, Germany; German Cancer Consortium (DKTK), Freiburg, Germany; German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Eleni Roussa
- Institute of Anatomy and Cell Biology, Department of Molecular Embryology, Albertstraße 17, 79104 Freiburg, Germany; Institute of Anatomy and Cell Biology, Department of Neuroanatomy, Albertstraße 17, 79104 Freiburg, Germany.
| | - Marco Prinz
- Institute of Neuropathology, Neurozentrum, Breisacherstraße 64, 79106 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, Germany.
| | - Kerstin Krieglstein
- Institute of Anatomy and Cell Biology, Department of Molecular Embryology, Albertstraße 17, 79104 Freiburg, Germany.
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21
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Corrado L, Magri S, Bagarotti A, Carecchio M, Piscosquito G, Pareyson D, Varrasi C, Vecchio D, Zonta A, Cantello R, Taroni F, D'Alfonso S. A novel synonymous mutation in the MPZ gene causing an aberrant splicing pattern and Charcot-Marie-Tooth disease type 1b. Neuromuscul Disord 2016; 26:516-20. [PMID: 27344971 DOI: 10.1016/j.nmd.2016.05.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 03/16/2016] [Accepted: 05/19/2016] [Indexed: 10/21/2022]
Abstract
Charcot-Marie-Tooth disease (CMT) is an inherited peripheral neuropathy with a heterogeneous genetic background. Here, we describe two CMT1B families with a mild sensory-motor neuropathy and a novel synonymous variant (c.309G > T, p.G103G) in exon 3 of the MPZ gene. Next generation sequencing analysis on a 94 CMT gene panel showed no mutations in other disease genes. In vitro splicing assay and mRNA expression analysis indicated that the c.309T variant enhances a cryptic donor splice site at position c.304 resulting in the markedly increased expression of the r.304_448del alternative transcript in patients' cells. This transcript is predicted to encode a truncated P0 protein (p.V102Cfs11*) lacking the transmembrane domain, thus suggesting a possible haploinsufficiency mechanism for this mutation. This is the third reported synonymous MPZ variant associated with CMT1 and affecting splicing. These data confirm the functional impact of synonymous variants on MPZ splicing and their possible role as disease-causing mutations rather than silent polymorphisms.
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Affiliation(s)
- L Corrado
- Human Genetics Laboratory, Department of Health Sciences, Amedeo Avogadro University, Via Solaroli 17, 28100 Novara, Italy; Interdisciplinary Research Center of Autoimmune Diseases (IRCAD), Amedeo Avogadro University, Novara, Italy.
| | - S Magri
- Unit of Genetics of Neurodegenerative and Metabolic Disease, Fondazione IRCCS Istituto Neurologico Carlo Besta, via Celoria 11, 20133 Milano, Italy
| | - A Bagarotti
- Human Genetics Laboratory, Department of Health Sciences, Amedeo Avogadro University, Via Solaroli 17, 28100 Novara, Italy
| | - M Carecchio
- Department of Neurology, Amedeo Avogadro University, Corso Mazzini 18, 28100 Novara, Italy
| | - G Piscosquito
- Unit of Clinic of Central and Peripheral Degenerative Neuropathies, Department of Clinical Neurosciences, Fondazione IRCCS Istituto Neurologico Carlo Besta, via Celoria 11, 20133 Milano, Italy
| | - D Pareyson
- Unit of Clinic of Central and Peripheral Degenerative Neuropathies, Department of Clinical Neurosciences, Fondazione IRCCS Istituto Neurologico Carlo Besta, via Celoria 11, 20133 Milano, Italy
| | - C Varrasi
- Department of Neurology, Amedeo Avogadro University, Corso Mazzini 18, 28100 Novara, Italy
| | - D Vecchio
- Department of Neurology, Amedeo Avogadro University, Corso Mazzini 18, 28100 Novara, Italy
| | - A Zonta
- Human Genetics Laboratory, Department of Health Sciences, Amedeo Avogadro University, Via Solaroli 17, 28100 Novara, Italy
| | - R Cantello
- Department of Neurology, Amedeo Avogadro University, Corso Mazzini 18, 28100 Novara, Italy
| | - F Taroni
- Unit of Genetics of Neurodegenerative and Metabolic Disease, Fondazione IRCCS Istituto Neurologico Carlo Besta, via Celoria 11, 20133 Milano, Italy
| | - S D'Alfonso
- Human Genetics Laboratory, Department of Health Sciences, Amedeo Avogadro University, Via Solaroli 17, 28100 Novara, Italy; Interdisciplinary Research Center of Autoimmune Diseases (IRCAD), Amedeo Avogadro University, Novara, Italy
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22
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Yang Y, Shi Y. L-periaxin interacts with S-periaxin through its PDZ domain. Neurosci Lett 2015; 609:23-9. [PMID: 26467811 DOI: 10.1016/j.neulet.2015.10.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 09/03/2015] [Accepted: 10/06/2015] [Indexed: 01/31/2023]
Abstract
Periaxin was first identified as a protein in myelinating Schwann cells through a screen of novel cytoskeleton-associated proteins in peripheral nerve myelination. The periaxin gene encodes two isoforms, namely, L- and S-periaxin, which are 1461 and 147 residues in size, respectively. Several loss-of-function mutations linked to autosomal recessive Dejerine-Sottas neuropathy and demyelinating Charcot-Marie-Tooth disease in periaxin have been described. In this study, the colocolization of L- and S-periaxin in the cytoplasm of RSC96 cells was found by immunofluorescence assays. The interaction between these two isoforms was confirmed by co-immunoprecipitation, fluorescence complementation experiment, and GST pull-down assay. Results also showed that the two periaxin isoforms interacted in the cytoplasm through the PDZ domain, and their interaction prevented the homodimerization of L-periaxin. S-periaxin may regulate the function of L-periaxin in Schwann cells.
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Affiliation(s)
- Yenan Yang
- Institute of Biotechnology, Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Shanxi University, Taiyuan 030006, PR China.
| | - Yawei Shi
- Institute of Biotechnology, Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Shanxi University, Taiyuan 030006, PR China.
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23
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Agrahari A, George Priya Doss C. Impact of I30T and I30M substitution in MPZ gene associated with Dejerine–Sottas syndrome type B (DSSB): A molecular modeling and dynamics. J Theor Biol 2015; 382:23-33. [DOI: 10.1016/j.jtbi.2015.06.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 05/21/2015] [Accepted: 06/10/2015] [Indexed: 11/28/2022]
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24
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Lupo V, Pascual-Pascual SI, Sancho P, Calpena E, Gutiérrez-Molina M, Mateo-Martínez G, Espinós C, Arriola-Pereda G. Complexity of the Hereditary Motor and Sensory Neuropathies: Clinical and Cellular Characterization of the MPZ p.D90E Mutation. J Child Neurol 2015; 30:1544-8. [PMID: 25694466 DOI: 10.1177/0883073815571049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 11/06/2014] [Indexed: 11/15/2022]
Abstract
Early-onset hereditary motor and sensory neuropathies are rare diseases representing a broad clinical and genetic spectrum. Without a notable familial history, the clinical diagnosis is complicated because acquired causes of peripheral neuropathy, such as inflammatory neuropathies, neuropathies with toxic causes, and nutritional deficiencies, must be considered. We examined the clinical, electrophysiological, and pathologic manifestations of a boy with an initial diagnosis of chronic inflammatory demyelinating polyneuropathy. The progression of the disease despite treatment led to a suspicion of hereditary motor and sensory neuropathy. Genetic testing revealed the presence of the MPZ p.D90E mutation in heterozygosis. To clarify the pathogenicity of this mutation and achieve a conclusive diagnosis, we investigated the MPZ p.D90E mutation through in silico and cellular approaches. This study broadens the clinical phenotype of hereditary motor and sensory neuropathy due to MPZ mutation and emphasises the difficulty of achieving an accurate genetic diagnosis in a sporadic patient to provide an appropriate pharmacologic treatment.
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Affiliation(s)
- Vincenzo Lupo
- Centro de Investigación Príncipe Felipe (CIPF), CIPF associated unit to the IBV-CSIC, Valencia, Spain Centro de Investigación Biomédica en Red de Enfermedades Raras, CIBERER, Valencia, Spain
| | | | - Paula Sancho
- Centro de Investigación Príncipe Felipe (CIPF), CIPF associated unit to the IBV-CSIC, Valencia, Spain Centro de Investigación Biomédica en Red de Enfermedades Raras, CIBERER, Valencia, Spain
| | - Eduardo Calpena
- Centro de Investigación Príncipe Felipe (CIPF), CIPF associated unit to the IBV-CSIC, Valencia, Spain Centro de Investigación Biomédica en Red de Enfermedades Raras, CIBERER, Valencia, Spain
| | | | | | - Carmen Espinós
- Centro de Investigación Príncipe Felipe (CIPF), CIPF associated unit to the IBV-CSIC, Valencia, Spain Centro de Investigación Biomédica en Red de Enfermedades Raras, CIBERER, Valencia, Spain Genetics Department, University of Valencia, Valencia, Spain
| | - Gema Arriola-Pereda
- Neuropediatrics Department, Hospital Universitario de Guadalajara, Guadalajara, Spain
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25
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Sanmaneechai O, Feely S, Scherer SS, Herrmann DN, Burns J, Muntoni F, Li J, Siskind CE, Day JW, Laura M, Sumner CJ, Lloyd TE, Ramchandren S, Shy RR, Grider T, Bacon C, Finkel RS, Yum SW, Moroni I, Piscosquito G, Pareyson D, Reilly MM, Shy ME. Genotype-phenotype characteristics and baseline natural history of heritable neuropathies caused by mutations in the MPZ gene. Brain 2015; 138:3180-92. [PMID: 26310628 DOI: 10.1093/brain/awv241] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Accepted: 06/30/2015] [Indexed: 11/14/2022] Open
Abstract
We aimed to characterize genotype-phenotype correlations and establish baseline clinical data for peripheral neuropathies caused by mutations in the myelin protein zero (MPZ) gene. MPZ mutations are the second leading cause of Charcot-Marie-Tooth disease type 1. Recent research makes clinical trials for patients with MPZ mutations a realistic possibility. However, the clinical severity varies with different mutations and natural history data on progression is sparse. We present cross-sectional data to begin to define the phenotypic spectrum and clinical baseline of patients with these mutations. A cohort of patients with MPZ gene mutations was identified in 13 centres of the Inherited Neuropathies Consortium - Rare Disease Clinical Research Consortium (INC-RDCRC) between 2009 and 2012 and at Wayne State University between 1996 and 2009. Patient phenotypes were quantified by the Charcot-Marie-Tooth disease neuropathy score version 1 or 2 and the Charcot-Marie-Tooth disease paediatric scale outcome instruments. Genetic testing was performed in all patients and/or in first- or second-degree relatives to document mutation in MPZ gene indicating diagnosis of Charcot-Marie-Tooth disease type 1B. There were 103 patients from 71 families with 47 different MPZ mutations with a mean age of 40 years (range 3-84 years). Patients and mutations were separated into infantile, childhood and adult-onset groups. The infantile onset group had higher Charcot-Marie-Tooth disease neuropathy score version 1 or 2 and slower nerve conductions than the other groups, and severity increased with age. Twenty-three patients had no family history of Charcot-Marie-Tooth disease. Sixty-one patients wore foot/ankle orthoses, 19 required walking assistance or support, and 10 required wheelchairs. There was hearing loss in 21 and scoliosis in 17. Forty-two patients did not begin walking until after 15 months of age. Half of the infantile onset patients then required ambulation aids or wheelchairs for ambulation. Our results demonstrate that virtually all MPZ mutations are associated with specific phenotypes. Early onset (infantile and childhood) phenotypes likely represent developmentally impaired myelination, whereas the adult-onset phenotype reflects axonal degeneration without antecedent demyelination. Data from this cohort of patients will provide the baseline data necessary for clinical trials of patients with Charcot-Marie-Tooth disease caused by MPZ gene mutations.
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Affiliation(s)
- Oranee Sanmaneechai
- 1 Department of Neurology, University of Iowa Hospitals and Clinics, Iowa, IA, USA 2 Division of Neurology, Department of Pediatrics, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Shawna Feely
- 1 Department of Neurology, University of Iowa Hospitals and Clinics, Iowa, IA, USA
| | - Steven S Scherer
- 3 The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - David N Herrmann
- 4 Department of Neurology, University of Rochester Medical Center, Rochester, NY, USA
| | - Joshua Burns
- 5 Arthritis and Musculoskeletal Research Group, University of Sydney / Paediatric Gait Analysis Service of NSW, Children's Hospital at Westmead, Sydney / Neuromuscular Research Group, Murdoch Childrens Research Institute, Melbourne, Australia
| | - Francesco Muntoni
- 6 University College London Institute of Child Health and Great Ormond Street Hospital, London, UK
| | - Jun Li
- 7 Department of Neurology, Vanderbilt University, Nashville, TN, USA
| | - Carly E Siskind
- 8 Department of Neurology, Stanford University, Stanford, CA, USA
| | - John W Day
- 8 Department of Neurology, Stanford University, Stanford, CA, USA
| | - Matilde Laura
- 9 MRC Centre for Neuromuscular Diseases, University College London Institute of Neurology, London, UK
| | - Charlotte J Sumner
- 10 Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Thomas E Lloyd
- 10 Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - Rosemary R Shy
- 1 Department of Neurology, University of Iowa Hospitals and Clinics, Iowa, IA, USA
| | - Tiffany Grider
- 1 Department of Neurology, University of Iowa Hospitals and Clinics, Iowa, IA, USA
| | - Chelsea Bacon
- 1 Department of Neurology, University of Iowa Hospitals and Clinics, Iowa, IA, USA
| | | | - Sabrina W Yum
- 3 The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA 13 Neuromuscular Program, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Isabella Moroni
- 14 Departments of Child Neurology, IRCCS Foundation, Carlo Besta Neurological Institute, Milan, Italy
| | - Giuseppe Piscosquito
- 15 Departments of Clinical Neurosciences, IRCCS Foundation, Carlo Besta Neurological Institute, Milan, Italy
| | - Davide Pareyson
- 15 Departments of Clinical Neurosciences, IRCCS Foundation, Carlo Besta Neurological Institute, Milan, Italy
| | - Mary M Reilly
- 9 MRC Centre for Neuromuscular Diseases, University College London Institute of Neurology, London, UK
| | - Michael E Shy
- 1 Department of Neurology, University of Iowa Hospitals and Clinics, Iowa, IA, USA
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26
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Demyelinating CMT–what’s known, what’s new and what’s in store? Neurosci Lett 2015; 596:14-26. [DOI: 10.1016/j.neulet.2015.01.059] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 01/23/2015] [Indexed: 02/06/2023]
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27
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Brennan KM, Shy ME. New and emerging treatments of Charcot–Marie–Tooth disease. Expert Opin Orphan Drugs 2015. [DOI: 10.1517/21678707.2015.1009037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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28
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Prada V, Capponi S, Ursino G, Alberti A, Callegari I, Passalacqua M, Marotta R, Mandich P, Bellone E, Schenone A, Grandis M. Sural nerve biopsy and functional studies support the pathogenic role of a novelMPZmutation. Neuropathology 2014; 35:254-9. [DOI: 10.1111/neup.12179] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 09/30/2014] [Indexed: 01/01/2023]
Affiliation(s)
- Valeria Prada
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal Child Health; Section of Neurology; University of Genova; Genova Italy
| | - Simona Capponi
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal Child Health; Section of Medical Genetics; University of Genova; Genova Italy
| | - Giulia Ursino
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal Child Health; Section of Neurology; University of Genova; Genova Italy
| | - Antonia Alberti
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal Child Health; Section of Neurology; University of Genova; Genova Italy
| | - Ilaria Callegari
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal Child Health; Section of Neurology; University of Genova; Genova Italy
| | - Mario Passalacqua
- Department of Experimental Medicine; Section of Biochemistry; University of Genova; Genova Italy
| | - Roberto Marotta
- Nanochemistry Department; Istituto Italiano di Tecnologia (IIT); Electron Microscopy Facility; Genova Italy
| | - Paola Mandich
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal Child Health; Section of Medical Genetics; University of Genova; Genova Italy
| | - Emilia Bellone
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal Child Health; Section of Medical Genetics; University of Genova; Genova Italy
| | - Angelo Schenone
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal Child Health; Section of Neurology; University of Genova; Genova Italy
| | - Marina Grandis
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal Child Health; Section of Neurology; University of Genova; Genova Italy
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29
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Sedzik J, Jastrzebski JP, Grandis M. Glycans of myelin proteins. J Neurosci Res 2014; 93:1-18. [PMID: 25213400 DOI: 10.1002/jnr.23462] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2014] [Revised: 06/19/2014] [Accepted: 07/07/2014] [Indexed: 01/04/2023]
Abstract
Human P0 is the main myelin glycoprotein of the peripheral nervous system. It can bind six different glycans, all linked to Asn(93) , the unique glycosylation site. Other myelin glycoproteins, also with a single glycosylation site (PMP22 at Asn(36) , MOG at Asn(31) ), bind only one glycan. The MAG has 10 glycosylation sites; the glycoprotein OMgp has 11 glycosylation sites. Aside from P0, no comprehensive data are available on other myelin glycoproteins. Here we review and analyze all published data on the physicochemical structure of the glycans linked to P0, PMP22, MOG, and MAG. Most data concern bovine P0, whose glycan moieties have an MW ranging from 1,294.56 Da (GP3) to 2,279.94 Da (GP5). The pI of glycosylated P0 protein varies from pH 9.32 to 9.46. The most charged glycan is MS2 containing three sulfate groups and one glucuronic acid; whereas the least charged one is the BA2 residue. All glycans contain one fucose and one galactose. The most mannose rich are the glycans MS2 and GP4, each of them has four mannoses; OPPE1 contains five N-acetylglucosamines and one sulfated glucuronic acid; GP4 contains one sialic acid. Furthermore, human P0 variants causing both gain and loss of glycosylation have been described and cause peripheral neuropathies with variable clinical severity. In particular, the substitution T(95) →M is a very common in Europe and is associated with a late-onset axonal neuropathy. Although peripheral myelin is made up largely of glycoproteins, mutations altering glycosylation have been described only in P0. This attractive avenue of research requires further study.
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Affiliation(s)
- Jan Sedzik
- Royal Institute of Technology, Department of Chemical Engineering, Protein Crystallization Facility, Stockholm, Sweden; National Institute of Physiological Sciences, Department of Neuroscience and Bioinformatics, Okazaki, Japan
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30
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Leoyklang P, Suphapeetiporn K, Srichomthong C, Tongkobpetch S, Fietze S, Dorward H, Cullinane AR, Gahl WA, Huizing M, Shotelersuk V. Disorders with similar clinical phenotypes reveal underlying genetic interaction: SATB2 acts as an activator of the UPF3B gene. Hum Genet 2013; 132:1383-93. [PMID: 23925499 DOI: 10.1007/s00439-013-1345-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 07/24/2013] [Indexed: 01/01/2023]
Abstract
Two syndromic cognitive impairment disorders have very similar craniofacial dysmorphisms. One is caused by mutations of SATB2, a transcription regulator and the other by heterozygous mutations leading to premature stop codons in UPF3B, encoding a member of the nonsense-mediated mRNA decay complex. Here we demonstrate that the products of these two causative genes function in the same pathway. We show that the SATB2 nonsense mutation in our patient leads to a truncated protein that localizes to the nucleus, forms a dimer with wild-type SATB2 and interferes with its normal activity. This suggests that the SATB2 nonsense mutation has a dominant negative effect. The patient's leukocytes had significantly decreased UPF3B mRNA compared to controls. This effect was replicated both in vitro, where siRNA knockdown of SATB2 in HEK293 cells resulted in decreased UPF3B expression, and in vivo, where embryonic tissue of Satb2 knockout mice showed significantly decreased Upf3b expression. Furthermore, chromatin immunoprecipitation demonstrates that SATB2 binds to the UPF3B promoter, and a luciferase reporter assay confirmed that SATB2 expression significantly activates gene transcription using the UPF3B promoter. These findings indicate that SATB2 activates UPF3B expression through binding to its promoter. This study emphasizes the value of recognizing disorders with similar clinical phenotypes to explore underlying mechanisms of genetic interaction.
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Affiliation(s)
- Petcharat Leoyklang
- Biomedical Science Program, Faculty of Graduate School, Chulalongkorn University, Bangkok, Thailand
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31
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Bai Y, Patzko A, Shy ME. Unfolded protein response, treatment and CMT1B. Rare Dis 2013; 1:e24049. [PMID: 25002989 PMCID: PMC3915562 DOI: 10.4161/rdis.24049] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 02/19/2013] [Indexed: 01/17/2023] Open
Abstract
CMT1B is the second most frequent autosomal dominant inherited neuropathy and is caused by assorted mutations of the myelin protein zero (MPZ) gene. MPZ mutations cause neuropathy gain of function mechanisms that are largely independent MPZs normal role of mediating myelin compaction. Whether there are only a few or multiple pathogenic mechanisms that cause CMT1B is unknown. Arg98Cys and Ser63Del MPZ are two CMT1B causing mutations that have been shown to cause neuropathy in mice at least in part by activating the unfolded protein response (UPR). We have recently treated Arg98Cys mice with derivatives of curcumin that improved the neuropathy and reduced UPR activation.1 Future studies will address whether manipulating the UPR will be a common or rare strategy for treating CMT1B or other forms of inherited neuropathies.
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Affiliation(s)
- Yunhong Bai
- Department of Neurology; Carver College of Medicine; University of Iowa; Iowa City, IA USA
| | - Agnes Patzko
- Department of Neurology; Carver College of Medicine; University of Iowa; Iowa City, IA USA
| | - Michael E Shy
- Department of Neurology; Carver College of Medicine; University of Iowa; Iowa City, IA USA
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32
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Pareyson D, Marchesi C, Salsano E. Dominant Charcot-Marie-Tooth syndrome and cognate disorders. HANDBOOK OF CLINICAL NEUROLOGY 2013; 115:817-845. [PMID: 23931817 DOI: 10.1016/b978-0-444-52902-2.00047-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Charcot-Marie-Tooth neuropathy (CMT) is a group of genetically heterogeneous disorders sharing a similar phenotype, characterized by wasting and weakness mainly involving the distal muscles of lower and upper limbs, variably associated with distal sensory loss and skeletal deformities. This chapter deals with dominantly transmitted CMT and related disorders, namely hereditary neuropathy with liability to pressure palsies (HNPP) and hereditary neuralgic amyotrophy (HNA). During the last 20 years, several genes have been uncovered associated with CMT and our understanding of the underlying molecular mechanisms has greatly improved. Consequently, a precise genetic diagnosis is now possible in the majority of cases, thus allowing proper genetic counseling. Although, unfortunately, treatment is still unavailable for all types of CMT, several cellular and animal models have been developed and some compounds have proved effective in these models. The first trials with ascorbic acid in CMT type 1A have been completed and, although negative, are providing relevant information on disease course and on how to prepare for future trials.
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Affiliation(s)
- Davide Pareyson
- Clinics of Central and Peripheral Degenerative Neuropathies Unit, Department of Clinical Neurosciences, IRCCS Foundation, C. Besta Neurological Institute, Milan, Italy.
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33
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Crone C, Krarup C. Neurophysiological approach to disorders of peripheral nerve. HANDBOOK OF CLINICAL NEUROLOGY 2013; 115:81-114. [PMID: 23931776 DOI: 10.1016/b978-0-444-52902-2.00006-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Disorders of the peripheral nerve system (PNS) are heterogeneous and may involve motor fibers, sensory fibers, small myelinated and unmyelinated fibers and autonomic nerve fibers, with variable anatomical distribution (single nerves, several different nerves, symmetrical affection of all nerves, plexus, or root lesions). Furthermore pathological processes may result in either demyelination, axonal degeneration or both. In order to reach an exact diagnosis of any neuropathy electrophysiological studies are crucial to obtain information about these variables. Conventional electrophysiological methods including nerve conduction studies and electromyography used in the study of patients suspected of having a neuropathy and the significance of the findings are discussed in detail and more novel and experimental methods are mentioned. Diagnostic considerations are based on a flow chart classifying neuropathies into eight categories based on mode of onset, distribution, and electrophysiological findings, and the electrophysiological characteristics in each type of neuropathy are discussed.
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Affiliation(s)
- Clarissa Crone
- Department of Clinical Neurophysiology, Rigshospitalet and University of Copenhagen, Copenhagen, Denmark
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34
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Patzkó Á, Bai Y, Saporta MA, Katona I, Wu X, Vizzuso D, Feltri ML, Wang S, Dillon LM, Kamholz J, Kirschner D, Sarkar FH, Wrabetz L, Shy ME. Curcumin derivatives promote Schwann cell differentiation and improve neuropathy in R98C CMT1B mice. Brain 2012; 135:3551-66. [PMID: 23250879 PMCID: PMC3577101 DOI: 10.1093/brain/aws299] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Revised: 09/25/2012] [Accepted: 09/30/2012] [Indexed: 11/12/2022] Open
Abstract
Charcot-Marie-Tooth disease type 1B is caused by mutations in myelin protein zero. R98C mice, an authentic model of early onset Charcot-Marie-Tooth disease type 1B, develop neuropathy in part because the misfolded mutant myelin protein zero is retained in the endoplasmic reticulum where it activates the unfolded protein response. Because oral curcumin, a component of the spice turmeric, has been shown to relieve endoplasmic reticulum stress and decrease the activation of the unfolded protein response, we treated R98C mutant mice with daily gastric lavage of curcumin or curcumin derivatives starting at 4 days of age and analysed them for clinical disability, electrophysiological parameters and peripheral nerve morphology. Heterozygous R98C mice treated with curcumin dissolved in sesame oil or phosphatidylcholine curcumin performed as well as wild-type littermates on a rotarod test and had increased numbers of large-diameter axons in their sciatic nerves. Treatment with the latter two compounds also increased compound muscle action potential amplitudes and the innervation of neuromuscular junctions in both heterozygous and homozygous R98C animals, but it did not improve nerve conduction velocity, myelin thickness, G-ratios or myelin period. The expression of c-Jun and suppressed cAMP-inducible POU (SCIP)-transcription factors that inhibit myelination when overexpressed-was also decreased by treatment. Consistent with its role in reducing endoplasmic reticulum stress, treatment with curcumin dissolved in sesame oil or phosphatidylcholine curcumin was associated with decreased X-box binding protein (XBP1) splicing. Taken together, these data demonstrate that treatment with curcumin dissolved in sesame oil or phosphatidylcholine curcumin improves the peripheral neuropathy of R98C mice by alleviating endoplasmic reticulum stress, by reducing the activation of unfolded protein response and by promoting Schwann cell differentiation.
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Affiliation(s)
- Ágnes Patzkó
- 1 Department of Neurology, Wayne State University, Detroit, MI 48201, USA
| | - Yunhong Bai
- 1 Department of Neurology, Wayne State University, Detroit, MI 48201, USA
- 2 Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Mario A. Saporta
- 1 Department of Neurology, Wayne State University, Detroit, MI 48201, USA
| | - István Katona
- 1 Department of Neurology, Wayne State University, Detroit, MI 48201, USA
| | - XingYao Wu
- 1 Department of Neurology, Wayne State University, Detroit, MI 48201, USA
- 2 Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Domenica Vizzuso
- 3 Hunter James Kelly Institute, School of Medicine and Biomedical Sciences, Dept of Neurology and Biochemistry, State University of New York at Buffalo, Buffalo, NY 14203, USA
- 4 Division of Genetics and Cell biology, San Raffaele Scientific Institute, DIBIT, Milano 20132, Italy
| | - M. Laura Feltri
- 3 Hunter James Kelly Institute, School of Medicine and Biomedical Sciences, Dept of Neurology and Biochemistry, State University of New York at Buffalo, Buffalo, NY 14203, USA
- 4 Division of Genetics and Cell biology, San Raffaele Scientific Institute, DIBIT, Milano 20132, Italy
| | - Suola Wang
- 1 Department of Neurology, Wayne State University, Detroit, MI 48201, USA
- 2 Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Lisa M. Dillon
- 1 Department of Neurology, Wayne State University, Detroit, MI 48201, USA
| | - John Kamholz
- 1 Department of Neurology, Wayne State University, Detroit, MI 48201, USA
| | - Daniel Kirschner
- 5 Department of Biology, Boston College, Chestnut Hill, MA 02467-3804, USA
| | - Fazlul H. Sarkar
- 6 Department of Pathology, Wayne State University, Detroit, MI 48201, USA
| | - Lawrence Wrabetz
- 3 Hunter James Kelly Institute, School of Medicine and Biomedical Sciences, Dept of Neurology and Biochemistry, State University of New York at Buffalo, Buffalo, NY 14203, USA
- 4 Division of Genetics and Cell biology, San Raffaele Scientific Institute, DIBIT, Milano 20132, Italy
| | - Michael E. Shy
- 1 Department of Neurology, Wayne State University, Detroit, MI 48201, USA
- 2 Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- 7 Centre for Molecular Medicine and Genetics, Wayne State University, Detroit, MI 48201, USA
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Abstract
The prenatal and infantile neuropathies are an uncommon and complex group of conditions, most of which are genetic. Despite advances in diagnostic techniques, approximately half of children presenting in infancy remain without a specific diagnosis. This review focuses on inherited demyelinating neuropathies presenting in the first year of life. We clarify the nomenclature used in these disorders, review the clinical features of demyelinating forms of Charcot-Marie-Tooth disease with early onset, and discuss the demyelinating infantile neuropathies associated with central nervous system involvement. Useful clinical, neurophysiologic, and neuropathologic features in the diagnostic work-up of these conditions are also presented.
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Affiliation(s)
- Eppie M Yiu
- Children's Neuroscience Centre, Royal Children's Hospital, Flemington Road, Parkville, Victoria, Australia
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Ramirez JD, Barnes PRJ, Mills KR, Bennett DLH. Intermediate Charcot-Marie-Tooth disease due to a novel Trp101Stop myelin protein zero mutation associated with debilitating neuropathic pain. Pain 2012; 153:1763-1768. [PMID: 22704856 PMCID: PMC3399778 DOI: 10.1016/j.pain.2012.05.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 05/11/2012] [Accepted: 05/14/2012] [Indexed: 11/03/2022]
Abstract
We report an English kindred affected across 4 generations with a hereditary neuropathy associated with debilitating neuropathic pain as the main clinical feature. The principal finding on clinical examination was sensory loss, and there was variable motor dysfunction. Electrophysiological studies revealed mild features of demyelination with median conduction velocity in the intermediate range. There was an autosomal-dominant pattern of inheritance, and genetic testing revealed a novel heterozygous Trp101X mutation in exon 3 coding for a portion of the extracellular domain of myelin protein zero. This is predicted to lead to premature termination of translation. Myelin protein zero is a key structural component of compact myelin, and over 100 mutations in this protein have been reported, which can give rise to neuropathies with either axonal, demyelinating, or intermediate features encompassing a wide range of severity. Chronic pain is an increasingly recognised sequela of certain hereditary neuropathies and may be musculoskeletal or neuropathic in origin. In this kindred, the neuropathy was relatively mild in severity, however, neuropathic pain was an important and disabling outcome.
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Affiliation(s)
- Juan D Ramirez
- Wolfson Centre for Age-Related Diseases, King's College London, London, UK Medical Director's Office, Western Sussex Hospitals, Worthing, UK Department of Clinical Neurosciences, King's College, London, UK
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Saporta MAC, Shy BR, Patzko A, Bai Y, Pennuto M, Ferri C, Tinelli E, Saveri P, Kirschner D, Crowther M, Southwood C, Wu X, Gow A, Feltri ML, Wrabetz L, Shy ME. MpzR98C arrests Schwann cell development in a mouse model of early-onset Charcot-Marie-Tooth disease type 1B. ACTA ACUST UNITED AC 2012; 135:2032-47. [PMID: 22689911 DOI: 10.1093/brain/aws140] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mutations in myelin protein zero (MPZ) cause Charcot-Marie-Tooth disease type 1B. Many dominant MPZ mutations, including R98C, present as infantile onset dysmyelinating neuropathies. We have generated an R98C 'knock-in' mouse model of Charcot-Marie-Tooth type 1B, where a mutation encoding R98C was targeted to the mouse Mpz gene. Both heterozygous (R98C/+) and homozygous (R98C/R98C) mice develop weakness, abnormal nerve conduction velocities and morphologically abnormal myelin; R98C/R98C mice are more severely affected. MpzR98C is retained in the endoplasmic reticulum of Schwann cells and provokes a transitory, canonical unfolded protein response. Ablation of Chop, a mediator of the protein kinase RNA-like endoplasmic reticulum kinase unfolded protein response pathway restores compound muscle action potential amplitudes of R98C/+ mice but does not alter the reduced conduction velocities, reduced axonal diameters or clinical behaviour of these animals. R98C/R98C Schwann cells are developmentally arrested in the promyelinating stage, whereas development is delayed in R98C/+ mice. The proportion of cells expressing c-Jun, an inhibitor of myelination, is elevated in mutant nerves, whereas the proportion of cells expressing the promyelinating transcription factor Krox-20 is decreased, particularly in R98C/R98C mice. Our results provide a potential link between the accumulation of MpzR98C in the endoplasmic reticulum and a developmental delay in myelination. These mice provide a model by which we can begin to understand the early onset dysmyelination seen in patients with R98C and similar mutations.
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Affiliation(s)
- Mario A C Saporta
- Department of Neurology, Wayne State University, Detroit, MI 48201, USA
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Prada V, Passalacqua M, Bono M, Luzzi P, Scazzola S, Nobbio LA, Capponi S, Bellone E, Mandich P, Mancardi G, Shy M, Schenone A, Grandis M. Gain of glycosylation: a new pathomechanism of myelin protein zero mutations. Ann Neurol 2012; 71:427-31. [PMID: 22451207 DOI: 10.1002/ana.22695] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We report the first case of a missense mutation in MPZ causing a gain of glycosylation in myelin protein zero, the main protein of peripheral nervous system myelin. The patient was affected by a severe demyelinating neuropathy caused by a missense mutation, D32N, that created a new glycosylation sequence. We confirmed that the mutant protein is hyperglycosylated, is partially retained into the Golgi apparatus in vitro, and disrupts intercellular adhesion. By sequential experiments, we demonstrated that hyperglycosylation is the main mechanism of this mutation. Gain of glycosylation is a new mechanism in Charcot-Marie-Tooth type 1B.
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Affiliation(s)
- Valeria Prada
- Department of Neurosciences, Ophthalmology, and Genetics, University of Genoa, Genoa, Italy
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Maeda MH, Mitsui J, Soong BW, Takahashi Y, Ishiura H, Hayashi S, Shirota Y, Ichikawa Y, Matsumoto H, Arai M, Okamoto T, Miyama S, Shimizu J, Inazawa J, Goto J, Tsuji S. Increased gene dosage of myelin protein zero causes Charcot-Marie-Tooth disease. Ann Neurol 2012; 71:84-92. [PMID: 22275255 DOI: 10.1002/ana.22658] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE On the basis of the hypothesis that copy number mutations of the genes encoding myelin compact proteins are responsible for myelin disorders in humans, we have explored the possibility of copy number mutations in patients with Charcot-Marie-Tooth disease (CMT) whose responsible genes remain undefined. METHODS A family with 6 affected members in 3 consecutive generations, presenting with motor and sensory demyelinating polyneuropathy, was investigated. Characteristic clinical features in this pedigree include Adie pupils and substantial intrafamilial variability in the age at onset, electrophysiological findings, and clinical severity. Nucleotide sequence analyses of PMP22, MPZ, or GJB1 and gene dosage study of PMP22 did not reveal causative mutations. Hence, we applied a custom-designed array for comparative genomic hybridization (CGH) analysis to conduct a comprehensive screening of copy number mutations involving any of the known causative genes for CMT other than PMP22. RESULTS The array CGH analyses revealed increased gene dosage involving the whole MPZ, and the flanking genes of SDHC and C1orf192. The gene dosage is estimated to be 5 copies. This mutation showed complete cosegregation with the disease phenotype in this pedigree. INTERPRETATION The increased gene dosage of MPZ and increased expression level of MPZ mRNA emphasize the important role of the dosage of the MPZ protein in the functional integrity of peripheral nerve myelin in humans, and provide a new insight into the pathogenic mechanisms underlying CMT.
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Affiliation(s)
- Meiko Hashimoto Maeda
- Department of Neurology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
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Clinical and cellular characterization of two novel MPZ mutations, p.I135M and p.Q187PfsX63. Clin Neurol Neurosurg 2012; 114:124-9. [DOI: 10.1016/j.clineuro.2011.09.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 08/19/2011] [Accepted: 09/27/2011] [Indexed: 11/17/2022]
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Abstract
BACKGROUND Charcot-Marie-Tooth disease (CMT) is the most common inherited disorder of the peripheral nervous system. The frequency of different CMT genotypes has been estimated in clinic populations, but prevalence data from the general population is lacking. Point mutations in the mitofusin 2 (MFN2) gene has been identified exclusively in Charcot-Marie-Tooth disease type 2 (CMT2), and in a single family with intermediate CMT. MFN2 point mutations are probably the most common cause of CMT2. The CMT phenotype caused by mutation in the myelin protein zero (MPZ) gene varies considerably, from early onset and severe forms to late onset and milder forms. The mechanism is not well understood. The myelin protein zero (P(0) ) mediates adhesion in the spiral wraps of the Schwann cell's myelin sheath. X-linked Charcot-Marie Tooth disease (CMTX) is caused by mutations in the connexin32 (cx32) gene that encodes a polypeptide which is arranged in hexameric array and form gap junctions. AIMS Estimate prevalence of CMT. Estimate frequency of Peripheral Myelin Protein 22 (PMP22) duplication and point mutations, insertions and deletions in Cx32, Early growth response 2 (EGR2), MFN2, MPZ, PMP22 and Small integral membrane protein of lysosome/late endosome (SIMPLE) genes. Description of novel mutations in Cx32, MFN2 and MPZ. Description of de novo mutations in MFN2. MATERIAL AND METHODS Our population based genetic epidemiological survey included persons with CMT residing in eastern Akershus County, Norway. The participants were interviewed and examined by one geneticist/neurologist, and classified clinically, neurophysiologically and genetically. Two-hundred and thirty-two consecutive unselected and unrelated CMT families with available DNA from all regions in Norway were included in the MFN2 study. We screened for point mutations in the MFN2 gene. We describe four novel mutations, two in the connexin32 gene and two in the MPZ gene. RESULTS A total of 245 affected from 116 CMT families from the general population of eastern Akershus county were included in the genetic epidemiological survey. In the general population 1 per 1214 persons (95% CI 1062-1366) has CMT. Charcot-Marie-Tooth disease type 1 (CMT1), CMT2 and intermediate CMT were found in 48.2%, 49.4% and 2.4% of the families, respectively. A mutation in the investigated genes was found in 27.2% of the CMT families and in 28.6% of the affected. The prevalence of the PMP22 duplication and mutations in the Cx32, MPZ and MFN2 genes was found in 13.6%, 6.2%, 1.2%, 6.2% of the families, and in 19.6%, 4.8%, 1.1%, 3.2% of the affected, respectively. None of the families had point mutations, insertions or deletions in the EGR2, PMP22 or SIMPLE genes. Four known and three novel mitofusin 2 (MFN2) point mutations in 8 unrelated Norwegian CMT families were identified. The novel point mutations were not found in 100 healthy controls. This corresponds to 3.4% (8/232) of CMT families having point mutations in MFN2. The phenotypes were compatible with CMT1 in two families, CMT2 in four families, intermediate CMT in one family and distal hereditary motor neuronopathy (dHMN) in one family. A point mutation in the MFN2 gene was found in 2.3% of CMT1, 5.5% of CMT2, 12.5% of intermediate CMT and 6.7% of dHMN families. Two novel missense mutations in the MPZ gene were identified. Family 1 had a c.368G>A (Gly123Asp) transition while family 2 and 3 had a c.103G>A (Asp35Asn) transition. The affected in family 1 had early onset and severe symptoms compatible with Dejerine-Sottas syndrome (DSS), while affected in family 2 and 3 had late onset, milder symptoms and axonal neuropathy compatible with CMT2. Two novel connexin32 mutations that cause early onset X-linked CMT were identified. Family 1 had a deletion c.225delG (R75fsX83) which causes a frameshift and premature stop codon at position 247 while family 2 had a c.536G>A (Cys179Tyr) transition which causes a change of the highly conserved cysteine residue, i.e. disruption of at least one of three disulfide bridges. The mean age at onset was in the first decade and the nerve conduction velocities were in the intermediate range. DISCUSSION Charcot-Marie-Tooth disease is the most common inherited neuropathy. At present 47 hereditary neuropathy genes are known, and an examination of all known genes would probably only identify mutations in approximately 50% of those with CMT. Thus, it is likely that at least 30-50 CMT genes are yet to be identified. The identified known and novel point mutations in the MFN2 gene expand the clinical spectrum from CMT2 and intermediate CMT to also include possibly CMT1 and the dHMN phenotypes. Thus, genetic analyses of the MFN2 gene should not be restricted to persons with CMT2. The phenotypic variation caused by different missense mutations in the MPZ gene is likely caused by different conformational changes of the MPZ protein which affects the functional tetramers. Severe changes of the MPZ protein cause dysfunctional tetramers and predominantly uncompacted myelin, i.e. the severe phenotypes congenital hypomyelinating neuropathy and DSS, while milder changes cause the phenotypes CMT1 and CMT2. The two novel mutations in the connexin32 gene are more severe than the majority of previously described mutations possibly due to the severe structural change of the gap junction they encode. CONCLUSION Charcot-Marie-Tooth disease is the most common inherited disorder of the peripheral nervous system with an estimated prevalence of 1 in 1214. CMT1 and CMT2 are equally frequent in the general population. The prevalence of PMP22 duplication and of mutations in Cx32, MPZ and MFN2 is 19.6%, 4.8%, 1.1% and 3.2%, respectively. The ratio of probable de novo mutations in CMT families was estimated to be 22.7%. Genotype- phenotype correlations for seven novel mutations in the genes Cx32 (2), MFN2 (3) and MPZ (2) are described. Two novel phenotypes were ascribed to the MFN2 gene, however further studies are needed to confirm that MFN2 mutations can cause CMT1 and dHMN.
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Affiliation(s)
- G J Braathen
- Head and Neck Research Group, Research Centre, Akershus University Hospital, Lørenskog, Norway.
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42
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Sevilla T, Lupo V, Sivera R, Marco-Marín C, Martínez-Rubio D, Rivas E, Hernández A, Palau F, Espinós C. Congenital hypomyelinating neuropathy due to a novel MPZ mutation. J Peripher Nerv Syst 2011; 16:347-52. [DOI: 10.1111/j.1529-8027.2011.00369.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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43
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Jung J, Coe H, Michalak M. Specialization of endoplasmic reticulum chaperones for the folding and function of myelin glycoproteins P0 and PMP22. FASEB J 2011; 25:3929-37. [DOI: 10.1096/fj.11-184911] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Joanna Jung
- Department of BiochemistryUniversity of Alberta Edmonton Alberta Canada
| | - Helen Coe
- Department of BiochemistryUniversity of Alberta Edmonton Alberta Canada
- Department of PediatricsUniversity of Alberta Edmonton Alberta Canada
| | - Marek Michalak
- Department of BiochemistryUniversity of Alberta Edmonton Alberta Canada
- Department of PediatricsUniversity of Alberta Edmonton Alberta Canada
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Taioli F, Cabrini I, Cavallaro T, Simonati A, Testi S, Fabrizi GM. Déjerine-Sottas syndrome with a silent nucleotide change of myelin protein zero gene. J Peripher Nerv Syst 2011; 16:59-64. [DOI: 10.1111/j.1529-8027.2011.00319.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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45
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46
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Novel MPZ mutations and congenital hypomyelinating neuropathy. Neuromuscul Disord 2011; 20:725-9. [PMID: 20621479 DOI: 10.1016/j.nmd.2010.06.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Revised: 06/01/2010] [Accepted: 06/15/2010] [Indexed: 01/09/2023]
Abstract
We report two new MPZ mutations causing congenital hypomyelinating neuropathies; c.368_382delGCACGTTCACTTGTG (in-frame deletion of five amino acids) and c.392A>G, Asn131Ser. Each child had clinical and electrodiagnostic features consistent with an inherited neuropathy, confirmed by sural nerve biopsy. The cases illustrate the clinically heterogeneity that exists even within early-onset forms of this disease. They also lend additional support to the emerging clinical and laboratory evidence that impaired intracellular protein trafficking may represent the cause of some congenital hypomyelinating neuropathies.
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47
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Piazza S, Baldinotti F, Fogli A, Conidi ME, Michelucci A, Ienco EC, Mancuso M, Simi P, Siciliano G. A new truncating MPZ mutation associated with a very mild CMT1 B phenotype. Neuromuscul Disord 2010; 20:817-9. [DOI: 10.1016/j.nmd.2010.08.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Revised: 07/21/2010] [Accepted: 08/17/2010] [Indexed: 12/25/2022]
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48
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Lei L, Han D, Gong S, Zheng J, Xu J. Mpz gene suppression by shRNA increases Schwann cell apoptosis in vitro. Neurol Sci 2010; 31:603-8. [PMID: 20552241 DOI: 10.1007/s10072-010-0341-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2009] [Accepted: 05/22/2010] [Indexed: 11/29/2022]
Abstract
We investigated the effects of short hairpin RNA (shRNA) on myelin protein zero (MPZ) gene expression in Schwann cells (SCs) in vitro and determined the effects of the MPZ gene suppression on the survival of SCs. The MPZ-specific shRNA was introduced into a lentiviral vector for expression under the U6 promoter, and the viral vector-based shRNAs were used to infect cultured SCs. The efficiency of MPZ knockdown was analyzed by real time-PCR (RT-PCR) and western blotting. Flow cytometric analysis and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) were used to determine the cell cycle and the amount of apoptosis of SCs. We found that MPZ shRNAs significantly inhibited the expression of the MPZ gene and induced SC apoptosis in vitro. These results provided interesting experimental evidence for understanding the mechanism of demyelinating neuropathies caused by MPZ gene malfunction.
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Affiliation(s)
- Li Lei
- Department of Otolaryngology, Affiliated Beijing Tongren Hospital, Capital Medical University, 1 Dongjiaominxiang, Dongcheng District, Beijing, 100730, People's Republic of China
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49
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Lee YC, Lin KP, Chang MH, Liao YC, Tsai CP, Liao KK, Soong BW. Cellular characterization of MPZ mutations presenting with diverse clinical phenotypes. J Neurol 2010; 257:1661-8. [PMID: 20461396 DOI: 10.1007/s00415-010-5590-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Revised: 04/05/2010] [Accepted: 04/30/2010] [Indexed: 11/25/2022]
Abstract
Mutations in MPZ, which encodes myelin protein zero (P(0)), may lead to different subtypes of Charcot-Marie-Tooth disease (CMT). The aim of this study was to characterize the cellular manifestations of various MPZ mutations associated with CMT1, Dejerine-Sottas syndrome (DSS) and CMT2, and to correlate their cellular and clinical phenotypes. Nine P(0) mutants associated with CMT1 (P(0)S63F, R98H, R277S, and S233fs), DSS (P(0) I30T and R98C), and CMT2 (P(0)S44F, D75V, and T124M), were investigated. Wild-type and mutant P(0) fused with fluorescent proteins were expressed in vitro to monitor their intracellular localization. An adhesiveness assay was used to evaluate the adhesiveness of the transfected cells. Protein localization and cell adhesiveness of each mutant protein were compared and correlated with their clinical phenotypes. Three different intracellular localization patterns of the mutant P(0) were observed. Wild-type P(0), P(0)I30T, S44F, S63F, D75V, T124M, and R227S were mostly localized on the cell membrane, P(0)R98H, and R98C were found in the endoplasmic reticulum (ER) or Golgi apparatus, and P(0)S233fs formed aggregates within the ER. Cells expressing mutant P(0), as compared with those expressing wild-type P(0), demonstrated variable degrees of reduction in the cell adhesiveness. The molecular patho-mechanisms of MPZ mutations are likely very complex and the clinical phenotype must be influenced by many genetic or environmental factors. This complexity may contribute to the highly variable clinical manifestations resulting from different MPZ mutations.
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Affiliation(s)
- Yi-Chung Lee
- Department of Neurology, National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC
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50
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Braathen GJ, Sand JC, Russell MB. Two novel missense mutations in the myelin protein zero gene causes Charcot-Marie-Tooth type 2 and Déjérine-Sottas syndrome. BMC Res Notes 2010; 3:99. [PMID: 20385006 PMCID: PMC2861067 DOI: 10.1186/1756-0500-3-99] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Accepted: 04/12/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The Charcot-Marie-Tooth (CMT) phenotype caused by mutation in the myelin protein zero (MPZ) gene varies considerably, from early onset and severe forms to late onset and milder forms. The mechanism is not well understood. The myelin protein zero (P0) mediates adhesion in the spiral wraps of the Schwann cell's myelin sheath. The crystalline structure of the extracellular domain of the myelin protein zero (P0ex) is known, while the transmembrane and intracellular structure is unknown. FINDINGS One novel missense mutation caused a milder late onset CMT type 2, while the second missense mutation caused a severe early onset phenotype compatible with Déjérine-Sottas syndrome. CONCLUSIONS The phenotypic variation caused by different missense mutations in the MPZ gene is likely caused by different conformational changes of the MPZ protein which affects the functional tetramers. Severe changes of the MPZ protein cause dysfunctional tetramers and predominantly uncompacted myelin, i.e. the severe phenotypes congenital hypomyelinating neuropathy and Déjérine-Sottas syndrome, while milder changes cause the phenotypes CMT type 1 and 2.
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Affiliation(s)
- Geir J Braathen
- Faculty Division Akershus University Hospital, University of Oslo, 1474 Nordbyhagen, Oslo, Norway.
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