1
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Maqboul A, Elsadek B. Tumor microenvironment (Part I): Tissue integrity in a rat model of peripheral neural cancer. Heliyon 2024; 10:e33932. [PMID: 39050471 PMCID: PMC11268353 DOI: 10.1016/j.heliyon.2024.e33932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 06/27/2024] [Accepted: 07/01/2024] [Indexed: 07/27/2024] Open
Abstract
ICAM-1 (intercellular adhesion molecule 1) and MPZ (myelin protein zero) are thought to be a factor in the integrity of nerve tissues. In this report, we attempted to trace the expression of ICAM-1, responsible for cell-to-cell adhesion, and of MPZ, the main constituent of myelin sheath, in malignant tissues of the sciatic nerve (SN) in inbred male Copenhagen rats. AT-1 Cells (anaplastic tumor 1) were injected in the perineurial sheath, and tissues of the SNs were collected after 7, 14 and 21 days and compared to a sham-operated group of rats (n = 6 each). Tissues were sectioned and histologically examined, under light microscope, and stained for measuring the immunoreactivity of ICAM-1 and MPZ under laser scanning microscope. The cancer model was established, and the tumor growth was confirmed. ICAM-1 showed severe decreases, proportional to the growing anaplastic cells, as compared to the sham group. MPZ revealed, however, a distinct defensive pattern before substantially decreasing in a comparison with sham. These results support the notion that malignancies damage peripheral nerves and cause severe axonal injury and loss of neuronal integrity, and clearly define the role of ICAM-1 and MPZ in safeguarding the nerve tissues.
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Affiliation(s)
- Ahmad Maqboul
- Department of Anesthesiology and Operative Intensive Care Medicine, Charité–School of Medicine Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
- Department of Biochemistry and Molecular Biology, College of Pharmacy, Al-Azhar University, Asyût, Egypt
| | - Bakheet Elsadek
- Department of Biochemistry and Molecular Biology, College of Pharmacy, Al-Azhar University, Asyût, Egypt
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2
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Krokengen OC, Touma C, Mularski A, Sutinen A, Dunkel R, Ytterdal M, Raasakka A, Mertens HDT, Simonsen AC, Kursula P. The cytoplasmic tail of myelin protein zero induces morphological changes in lipid membranes. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184368. [PMID: 38971517 DOI: 10.1016/j.bbamem.2024.184368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 06/24/2024] [Accepted: 07/01/2024] [Indexed: 07/08/2024]
Abstract
The major myelin protein expressed by the peripheral nervous system Schwann cells is protein zero (P0), which represents 50% of the total protein content in myelin. This 30-kDa integral membrane protein consists of an immunoglobulin (Ig)-like domain, a transmembrane helix, and a 69-residue C-terminal cytoplasmic tail (P0ct). The basic residues in P0ct contribute to the tight packing of myelin lipid bilayers, and alterations in the tail affect how P0 functions as an adhesion molecule necessary for the stability of compact myelin. Several neurodegenerative neuropathies are related to P0, including the more common Charcot-Marie-Tooth disease (CMT) and Dejerine-Sottas syndrome (DSS) as well as rare cases of motor and sensory polyneuropathy. We found that high P0ct concentrations affected the membrane properties of bicelles and induced a lamellar-to-inverted hexagonal phase transition, which caused bicelles to fuse into long, protein-containing filament-like structures. These structures likely reflect the formation of semicrystalline lipid domains with potential relevance for myelination. Not only is P0ct important for stacking lipid membranes, but time-lapse fluorescence microscopy also shows that it might affect membrane properties during myelination. We further describe recombinant production and low-resolution structural characterization of full-length human P0. Our findings shed light on P0ct effects on membrane properties, and with the successful purification of full-length P0, we have new tools to study the role of P0 in myelin formation and maintenance in vitro.
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Affiliation(s)
- Oda C Krokengen
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Christine Touma
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Anna Mularski
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense, Denmark
| | - Aleksi Sutinen
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Ryan Dunkel
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Marie Ytterdal
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Arne Raasakka
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Haydyn D T Mertens
- European Molecular Biology Laboratory EMBL, Hamburg Site, c/o DESY, Hamburg, Germany
| | - Adam Cohen Simonsen
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense, Denmark
| | - Petri Kursula
- Department of Biomedicine, University of Bergen, Bergen, Norway; Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Oulu, Finland.
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3
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Schiavon CR, Shadel GS, Manor U. Impaired Mitochondrial Mobility in Charcot-Marie-Tooth Disease. Front Cell Dev Biol 2021; 9:624823. [PMID: 33598463 PMCID: PMC7882694 DOI: 10.3389/fcell.2021.624823] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 01/05/2021] [Indexed: 12/13/2022] Open
Abstract
Charcot-Marie-Tooth (CMT) disease is a progressive, peripheral neuropathy and the most commonly inherited neurological disorder. Clinical manifestations of CMT mutations are typically limited to peripheral neurons, the longest cells in the body. Currently, mutations in at least 80 different genes are associated with CMT and new mutations are regularly being discovered. A large portion of the proteins mutated in axonal CMT have documented roles in mitochondrial mobility, suggesting that organelle trafficking defects may be a common underlying disease mechanism. This review will focus on the potential role of altered mitochondrial mobility in the pathogenesis of axonal CMT, highlighting the conceptional challenges and potential experimental and therapeutic opportunities presented by this "impaired mobility" model of the disease.
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Affiliation(s)
- Cara R. Schiavon
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, United States
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, United States
| | - Gerald S. Shadel
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, United States
| | - Uri Manor
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, United States
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4
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Taniguchi T, Ando M, Okamoto Y, Yoshimura A, Higuchi Y, Hashiguchi A, Shiga K, Hayashida A, Hatano T, Ishiura H, Mitsui J, Hattori N, Mizuno T, Nakagawa M, Tsuji S, Takashima H. Genetic spectrum of Charcot-Marie-Tooth disease associated with myelin protein zero gene variants in Japan. Clin Genet 2020; 99:359-375. [PMID: 33179255 PMCID: PMC7898366 DOI: 10.1111/cge.13881] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 11/04/2020] [Accepted: 11/04/2020] [Indexed: 12/24/2022]
Abstract
We aimed to reveal the genetic features associated with MPZ variants in Japan. From April 2007 to August 2017, 64 patients with 23 reported MPZ variants and 21 patients with 17 novel MPZ variants were investigated retrospectively. Variation in MPZ variants and the pathogenicity of novel variants was examined according to the American College of Medical Genetics standards and guidelines. Age of onset, cranial nerve involvement, serum creatine kinase (CK), and cerebrospinal fluid (CSF) protein were also analyzed. We identified 64 CMT patients with reported MPZ variants. The common variants observed in Japan were different from those observed in other countries. We identified 11 novel pathogenic variants from 13 patients. Six novel MPZ variants in eight patients were classified as likely benign or uncertain significance. Cranial nerve involvement was confirmed in 20 patients. Of 30 patients in whom serum CK levels were evaluated, eight had elevated levels. Most of the patients had age of onset >20 years. In another subset of 30 patients, 18 had elevated CSF protein levels; four of these patients had spinal diseases and two had enlarged nerve root or cauda equina. Our results suggest genetic diversity across patients with MPZ variants.
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Affiliation(s)
- Takaki Taniguchi
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Masahiro Ando
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Yuji Okamoto
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.,Department of Physical Therapy, School of Health Sciences, Faculty of Medicine, Kagoshima University, Kagoshima, Japan
| | - Akiko Yoshimura
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Yujiro Higuchi
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Akihiro Hashiguchi
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Kensuke Shiga
- Department of Neurology, Matsushita Memorial Hospital, Osaka, Japan.,Department of Neurology, Kyoto prefectural University of Medicine, Kyoto, Japan
| | - Arisa Hayashida
- Department of Neurology, Juntendo University School of Medicine, Tokyo, Japan
| | - Taku Hatano
- Department of Neurology, Juntendo University School of Medicine, Tokyo, Japan
| | - Hiroyuki Ishiura
- Department of Molecular Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Jun Mitsui
- Department of Molecular Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Nobutaka Hattori
- Department of Neurology, Juntendo University School of Medicine, Tokyo, Japan
| | - Toshiki Mizuno
- Department of Neurology, Kyoto prefectural University of Medicine, Kyoto, Japan
| | - Masanori Nakagawa
- Department of Neurology, Kyoto prefectural University of Medicine, Kyoto, Japan.,North Medical Center, Kyoto prefectural University of Medicine, Kyoto, Japan
| | - Shoji Tsuji
- Department of Molecular Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,Institute of Medical Genomics, International University of Health and Welfare, Chiba, Japan
| | - Hiroshi Takashima
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
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5
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Sun SC, Ma D, Li MY, Zhang RX, Huang C, Huang HJ, Xie YZ, Wang ZJ, Liu J, Cai DC, Liu CX, Yang Q, Bao FX, Gong XL, Li JR, Hui Z, Wei XF, Zhong JM, Zhou WJ, Shang X, Zhang C, Liu XG, Tang BS, Xiong F, Xu XM. Mutations in C1orf194, encoding a calcium regulator, cause dominant Charcot-Marie-Tooth disease. Brain 2020; 142:2215-2229. [PMID: 31199454 DOI: 10.1093/brain/awz151] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 03/13/2019] [Accepted: 04/10/2019] [Indexed: 12/27/2022] Open
Abstract
Charcot-Marie-Tooth disease is a hereditary motor and sensory neuropathy exhibiting great clinical and genetic heterogeneity. Here, the identification of two heterozygous missense mutations in the C1orf194 gene at 1p21.2-p13.2 with Charcot-Marie-Tooth disease are reported. Specifically, the p.I122N mutation was the cause of an intermediate form of Charcot-Marie-Tooth disease, and the p.K28I missense mutation predominately led to the demyelinating form. Functional studies demonstrated that the p.K28I variant significantly reduced expression of the protein, but the p.I122N variant increased. In addition, the p.I122N mutant protein exhibited the aggregation in neuroblastoma cell lines and the patient's peroneal nerve. Either gain-of-function or partial loss-of-function mutations to C1ORF194 can specify different causal mechanisms responsible for Charcot-Marie-Tooth disease with a wide range of clinical severity. Moreover, a knock-in mouse model confirmed that the C1orf194 missense mutation p.I121N led to impairments in motor and neuromuscular functions, and aberrant myelination and axonal phenotypes. The loss of normal C1ORF194 protein altered intracellular Ca2+ homeostasis and upregulated Ca2+ handling regulatory proteins. These findings describe a novel protein with vital functions in peripheral nervous systems and broaden the causes of Charcot-Marie-Tooth disease, which open new avenues for the diagnosis and treatment of related neuropathies.
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Affiliation(s)
- Shun-Chang Sun
- Department of Clinical Laboratory, Ruijin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, P.R. China
| | - Di Ma
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, P.R. China
| | - Mei-Yi Li
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, P.R. China
| | - Ru-Xu Zhang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Cheng Huang
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, P.R. China
| | - Hua-Jie Huang
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, P.R. China
| | - Yong-Zhi Xie
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Zhong-Ju Wang
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, P.R. China
| | - Jun Liu
- Department of Neurology and Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, P.R. China
| | - De-Cheng Cai
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, P.R. China
| | - Cui-Xian Liu
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, P.R. China
| | - Qi Yang
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, P.R. China
| | - Fei-Xiang Bao
- Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, P.R. China
| | - Xiao-Li Gong
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, P.R. China
| | - Jie-Ru Li
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, P.R. China
| | - Zheng Hui
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou, P.R. China
| | - Xiao-Feng Wei
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, P.R. China
| | - Jian-Mei Zhong
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, P.R. China
| | - Wan-Jun Zhou
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, P.R. China
| | - Xuan Shang
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, P.R. China
| | - Cheng Zhang
- Department of Neurology, First Affiliated Hospital, Sun Yat-sen University, Guangzhou, P.R. China
| | - Xing-Guo Liu
- Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, P.R. China
| | - Bei-Sha Tang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Fu Xiong
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, P.R. China.,Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Guangzhou 510515, P.R. China.,Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Guangzhou, Guangdong Province, P.R.China
| | - Xiang-Min Xu
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, P.R. China.,Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Guangzhou 510515, P.R. China.,Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Guangzhou, Guangdong Province, P.R.China.,Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brian Science and Brain-Inspired Intelligence, Southern Medical University, Guangzhou 510515, P.R. China
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6
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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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7
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Neuropathy-related mutations alter the membrane binding properties of the human myelin protein P0 cytoplasmic tail. PLoS One 2019; 14:e0216833. [PMID: 31173589 PMCID: PMC6555526 DOI: 10.1371/journal.pone.0216833] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 04/29/2019] [Indexed: 01/19/2023] Open
Abstract
Schwann cells myelinate selected axons in the peripheral nervous system (PNS) and contribute to fast saltatory conduction via the formation of compact myelin, in which water is excluded from between tightly adhered lipid bilayers. Peripheral neuropathies, such as Charcot-Marie-Tooth disease (CMT) and Dejerine-Sottas syndrome (DSS), are incurable demyelinating conditions that result in pain, decrease in muscle mass, and functional impairment. Many Schwann cell proteins, which are directly involved in the stability of compact myelin or its development, are subject to mutations linked to these neuropathies. The most abundant PNS myelin protein is protein zero (P0); point mutations in this transmembrane protein cause CMT subtype 1B and DSS. P0 tethers apposing lipid bilayers together through its extracellular immunoglobulin-like domain. Additionally, P0 contains a cytoplasmic tail (P0ct), which is membrane-associated and contributes to the physical properties of the lipid membrane. Six CMT- and DSS-associated missense mutations have been reported in P0ct. We generated recombinant disease mutant variants of P0ct and characterized them using biophysical methods. Compared to wild-type P0ct, some mutants have negligible differences in function and folding, while others highlight functionally important amino acids within P0ct. For example, the D224Y variant of P0ct induced tight membrane multilayer stacking. Our results show a putative molecular basis for the hypermyelinating phenotype observed in patients with this particular mutation and provide overall information on the effects of disease-linked mutations in a flexible, membrane-binding protein segment. Using neutron reflectometry, we additionally show that P0ct embeds deep into a lipid bilayer, explaining the observed effects of P0ct on the physical properties of the membrane.
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8
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Salpietro V, Manole A, Efthymiou S, Houlden H. A Review of Copy Number Variants in Inherited Neuropathies. Curr Genomics 2018; 19:412-419. [PMID: 30258273 PMCID: PMC6128387 DOI: 10.2174/1389202919666180330153316] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 11/23/2016] [Accepted: 03/13/2018] [Indexed: 11/22/2022] Open
Abstract
The rapid development in the last 10-15 years of microarray technologies, such as oligonucleotide array Comparative Genomic Hybridization (CGH) and Single Nucleotide Polymorphisms (SNP) genotyping array, has improved the identification of fine chromosomal structural variants, ranging in length from kilobases (kb) to megabases (Mb), as an important cause of genetic differences among healthy individuals and also as disease-susceptibility and/or disease-causing factors. Structural genomic variations due to unbalanced chromosomal rearrangements are known as Copy-Number Variants (CNVs) and these include variably sized deletions, duplications, triplications and translocations. CNVs can significantly contribute to human diseases and rearrangements in several dosage-sensitive genes have been identified as an important causative mechanism in the molecular aetiology of Charcot-Marie-Tooth (CMT) disease and of several CMT-related disorders, a group of inherited neuropathies with a broad range of clinical phenotypes, inheritance patterns and causative genes. Duplications or deletions of the dosage-sensitive gene PMP22 mapped to chromosome 17p12 represent the most frequent causes of CMT type 1A and Hereditary Neuropathy with liability to Pressure Palsies (HNPP), respectively. Additionally, CNVs have been identified in patients with other CMT types (e.g., CMT1X, CMT1B, CMT4D) and different hereditary poly- (e.g., giant axonal neuropathy) and focal- (e.g., hereditary neuralgic amyotrophy) neuropathies, supporting the notion of hereditary peripheral nerve diseases as possible genomic disorders and making crucial the identification of fine chromosomal rearrangements in the molecular assessment of such patients. Notably, the application of advanced computational tools in the analysis of Next-Generation Sequencing (NGS) data has emerged in recent years as a powerful technique for identifying a genome-wide scale complex structural variants (e.g., as the ones resulted from balanced rearrangements) and also smaller pathogenic (intragenic) CNVs that often remain beyond the detection limit of most conventional genomic microarray analyses; in the context of inherited neuropathies where more than 70 disease-causing genes have been identified to date, NGS and particularly Whole-Genome Sequencing (WGS) hold the potential to reduce the number of genomic assays required per patient to reach a diagnosis, analyzing with a single test all the Single Nucleotide Variants (SNVs) and CNVs in the genes possibly implicated in this heterogeneous group of disorders.
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Affiliation(s)
- Vincenzo Salpietro
- Department of Molecular Neuroscience, Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Andreea Manole
- Department of Molecular Neuroscience, Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Stephanie Efthymiou
- Department of Molecular Neuroscience, Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Henry Houlden
- Department of Molecular Neuroscience, Institute of Neurology, University College London, London WC1N 3BG, UK
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9
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DHTKD1 Deficiency Causes Charcot-Marie-Tooth Disease in Mice. Mol Cell Biol 2018; 38:MCB.00085-18. [PMID: 29661920 DOI: 10.1128/mcb.00085-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 04/08/2018] [Indexed: 01/20/2023] Open
Abstract
DHTKD1, a part of 2-ketoadipic acid dehydrogenase complex, is involved in lysine and tryptophan catabolism. Mutations in DHTKD1 block the metabolic pathway and cause 2-aminoadipic and 2-oxoadipic aciduria (AMOXAD), an autosomal recessive inborn metabolic disorder. In addition, a nonsense mutation in DHTKD1 that we identified previously causes Charcot-Marie-Tooth disease (CMT) type 2Q, one of the most common inherited neurological disorders affecting the peripheral nerves in the musculature. However, the comprehensive molecular mechanism underlying CMT2Q remains elusive. Here, we show that Dhtkd1-/- mice mimic the major aspects of CMT2 phenotypes, characterized by progressive weakness and atrophy in the distal parts of limbs with motor and sensory dysfunctions, which are accompanied with decreased nerve conduction velocity. Moreover, DHTKD1 deficiency causes severe metabolic abnormalities and dramatically increased levels of 2-ketoadipic acid (2-KAA) and 2-aminoadipic acid (2-AAA) in urine. Further studies revealed that both 2-KAA and 2-AAA could stimulate insulin biosynthesis and secretion. Subsequently, elevated insulin regulates myelin protein zero (Mpz) transcription in Schwann cells via upregulating the expression of early growth response 2 (Egr2), leading to myelin structure damage and axonal degeneration. Finally, 2-AAA-fed mice do reproduce phenotypes similar to CMT2Q phenotypes. In conclusion, we have demonstrated that loss of DHTKD1 causes CMT2Q-like phenotypes through dysregulation of Mpz mRNA and protein zero (P0) which are closely associated with elevated DHTKD1 substrate and insulin levels. These findings further indicate an important role of metabolic disorders in addition to mitochondrial insufficiency in the pathogenesis of peripheral neuropathies.
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10
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Cutrupi AN, Brewer MH, Nicholson GA, Kennerson M. Structural variations causing inherited peripheral neuropathies: A paradigm for understanding genomic organization, chromatin interactions, and gene dysregulation. Mol Genet Genomic Med 2018; 6:422-433. [PMID: 29573232 PMCID: PMC6014456 DOI: 10.1002/mgg3.390] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 02/09/2018] [Accepted: 03/01/2018] [Indexed: 11/16/2022] Open
Abstract
Inherited peripheral neuropathies (IPNs) are a clinically and genetically heterogeneous group of diseases affecting the motor and sensory peripheral nerves. IPNs have benefited from gene discovery and genetic diagnosis using next-generation sequencing with over 80 causative genes available for testing. Despite this success, up to 50% of cases remain genetically unsolved. In the absence of protein coding mutations, noncoding DNA or structural variation (SV) mutations are a possible explanation. The most common IPN, Charcot-Marie-Tooth neuropathy type 1A (CMT1A), is caused by a 1.5 Mb duplication causing trisomy of the dosage sensitive gene PMP22. Using genome sequencing, we recently identified two large genomic rearrangements causing IPN subtypes X-linked CMT (CMTX3) and distal hereditary motor neuropathy (DHMN1), thereby expanding the spectrum of SV mutations causing IPN. Understanding how newly discovered SVs can cause IPN may serve as a useful paradigm to examine the role of topologically associated domains (TADs), chromatin interactions, and gene dysregulation in disease. This review will describe the growing role of SV in the pathogenesis of IPN and the importance of considering this type of mutation in Mendelian diseases where protein coding mutations cannot be identified.
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Affiliation(s)
- Anthony N. Cutrupi
- Northcott Neuroscience LaboratoryANZAC Research InstituteSydneyNSWAustralia
- Sydney Medical SchoolUniversity of SydneySydneyNSWAustralia
| | - Megan H. Brewer
- Northcott Neuroscience LaboratoryANZAC Research InstituteSydneyNSWAustralia
- Sydney Medical SchoolUniversity of SydneySydneyNSWAustralia
| | - Garth A. Nicholson
- Northcott Neuroscience LaboratoryANZAC Research InstituteSydneyNSWAustralia
- Sydney Medical SchoolUniversity of SydneySydneyNSWAustralia
- Molecular Medicine LaboratoryConcord HospitalSydneyNSWAustralia
| | - Marina L. Kennerson
- Northcott Neuroscience LaboratoryANZAC Research InstituteSydneyNSWAustralia
- Sydney Medical SchoolUniversity of SydneySydneyNSWAustralia
- Molecular Medicine LaboratoryConcord HospitalSydneyNSWAustralia
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11
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VerPlank JJS, Lokireddy S, Feltri ML, Goldberg AL, Wrabetz L. Impairment of protein degradation and proteasome function in hereditary neuropathies. Glia 2017; 66:379-395. [PMID: 29076578 DOI: 10.1002/glia.23251] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 09/10/2017] [Accepted: 10/09/2017] [Indexed: 01/02/2023]
Abstract
In several neurodegenerative diseases in which misfolded proteins accumulate there is impairment of the ubiquitin proteasome system (UPS). We tested if a similar disruption of proteostasis occurs in hereditary peripheral neuropathies. In sciatic nerves from mouse models of two human neuropathies, Myelin Protein Zero mutation (S63del) and increased copy number (P0 overexpression), polyubiquitinated proteins accumulated, and the overall rates of protein degradation were decreased. 26S proteasomes affinity-purified from sciatic nerves of S63del mice were defective in degradation of peptides and a ubiquitinated protein, unlike proteasomes from P0 overexpression, which appeared normal. Nevertheless, cellular levels of 26S proteasomes were increased in both, through the proteolytic-activation of the transcription factor Nrf1, as occurs in response to proteasome inhibitors. In S63del, increased amounts of the deubiquitinating enzymes USP14, UCH37, and USP5 were associated with proteasomes, the first time this has been reported in a human disease model. Inhibitors of USP14 increased the rate of protein degradation in S63del sciatic nerves and unexpectedly increased the phosphorylation of eIF2α by Perk. Thus, proteasome content, composition and activity are altered in these diseases and USP14 inhibitors have therapeutic potential in S63del neuropathy.
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Affiliation(s)
- Jordan J S VerPlank
- Hunter James Kelly Research Institute and Departments of, Biochemistry and Neurology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York.,Harvard Medical School, Boston, Massachusetts
| | | | - M Laura Feltri
- Hunter James Kelly Research Institute and Departments of, Biochemistry and Neurology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York
| | | | - Lawrence Wrabetz
- Hunter James Kelly Research Institute and Departments of, Biochemistry and Neurology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York
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12
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Brewer MH, Chaudhry R, Qi J, Kidambi A, Drew AP, Menezes MP, Ryan MM, Farrar MA, Mowat D, Subramanian GM, Young HK, Zuchner S, Reddel SW, Nicholson GA, Kennerson ML. Whole Genome Sequencing Identifies a 78 kb Insertion from Chromosome 8 as the Cause of Charcot-Marie-Tooth Neuropathy CMTX3. PLoS Genet 2016; 12:e1006177. [PMID: 27438001 PMCID: PMC4954712 DOI: 10.1371/journal.pgen.1006177] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 06/15/2016] [Indexed: 11/18/2022] Open
Abstract
With the advent of whole exome sequencing, cases where no pathogenic coding mutations can be found are increasingly being observed in many diseases. In two large, distantly-related families that mapped to the Charcot-Marie-Tooth neuropathy CMTX3 locus at chromosome Xq26.3-q27.3, all coding mutations were excluded. Using whole genome sequencing we found a large DNA interchromosomal insertion within the CMTX3 locus. The 78 kb insertion originates from chromosome 8q24.3, segregates fully with the disease in the two families, and is absent from the general population as well as 627 neurologically normal chromosomes from in-house controls. Large insertions into chromosome Xq27.1 are known to cause a range of diseases and this is the first neuropathy phenotype caused by an interchromosomal insertion at this locus. The CMTX3 insertion represents an understudied pathogenic structural variation mechanism for inherited peripheral neuropathies. Our finding highlights the importance of considering all structural variation types when studying unsolved inherited peripheral neuropathy cases with no pathogenic coding mutations.
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Affiliation(s)
- Megan H. Brewer
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord, New South Wales, Australia
- Sydney Medical School, University of Sydney, Camperdown, New South Wales, Australia
- * E-mail:
| | - Rabia Chaudhry
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord, New South Wales, Australia
- Sydney Medical School, University of Sydney, Camperdown, New South Wales, Australia
| | - Jessica Qi
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord, New South Wales, Australia
- Discipline of Pathology, University of Sydney, Camperdown, New South Wales, Australia
| | - Aditi Kidambi
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord, New South Wales, Australia
| | - Alexander P. Drew
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord, New South Wales, Australia
| | - Manoj P. Menezes
- The Institute for Neuroscience and Muscle Research, The Children’s Hospital at Westmead, Westmead, New South Wales, Australia
- T.Y. Nelson Department of Neurology and Neurosurgery, The Children’s Hospital at Westmead, Westmead, New South Wales, Australia
- Paediatrics and Child Health, University of Sydney, Camperdown, New South Wales, Australia
| | - Monique M. Ryan
- Department of Neurology, Royal Children’s Hospital, Parkville, Victoria, Australia
- Murdoch Childrens Research Institute, Parkville, Victoria, Australia
- Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia
| | - Michelle A. Farrar
- Department of Neurology, Sydney Children’s Hospital, Randwick, New South Wales, Australia
- School of Women’s and Children’s Health, UNSW Medicine, University of New South Wales, Kensington, New South Wales, Australia
| | - David Mowat
- School of Women’s and Children’s Health, UNSW Medicine, University of New South Wales, Kensington, New South Wales, Australia
- Department of Medical Genetics, Sydney Children’s Hospital, Randwick, New South Wales, Australia
| | - Gopinath M. Subramanian
- Department of Paediatrics, John Hunter Children’s Hospital, Newcastle, New South Wales, Australia
| | - Helen K. Young
- Department of Paediatrics, Royal North Shore Hospital, St Leonards, New South Wales, Australia
- Northern Clinical School, Sydney Medical School, University of Sydney, St Leonards, New South Wales, Australia
- Department of Neurogenetics, The Children’s Hospital at Westmead, Westmead, New South Wales, Australia
| | - Stephan Zuchner
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida, United States of America
- Dr. John T. Macdonald Department of Human Genetics, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Stephen W. Reddel
- Department of Neurology, Concord Repatriation General Hospital, Concord, New South Wales, Australia
| | - Garth A. Nicholson
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord, New South Wales, Australia
- Sydney Medical School, University of Sydney, Camperdown, New South Wales, Australia
- Molecular Medicine, Concord Repatriation General Hospital, Concord, New South Wales, Australia
| | - Marina L. Kennerson
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord, New South Wales, Australia
- Sydney Medical School, University of Sydney, Camperdown, New South Wales, Australia
- Molecular Medicine, Concord Repatriation General Hospital, Concord, New South Wales, Australia
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13
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Wang W, Wang C, Dawson DB, Thorland EC, Lundquist PA, Eckloff BW, Wu Y, Baheti S, Evans JM, Scherer SS, Dyck PJ, Klein CJ. Target-enrichment sequencing and copy number evaluation in inherited polyneuropathy. Neurology 2016; 86:1762-71. [PMID: 27164712 DOI: 10.1212/wnl.0000000000002659] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Accepted: 01/05/2016] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To assess the efficiency of target-enrichment next-generation sequencing (NGS) with copy number assessment in inherited neuropathy diagnosis. METHODS A 197 polyneuropathy gene panel was designed to assess for mutations in 93 patients with inherited or idiopathic neuropathy without known genetic cause. We applied our novel copy number variation algorithm on NGS data, and validated the identified copy number mutations using CytoScan (Affymetrix). Cost and efficacy of this targeted NGS approach was compared to earlier evaluations. RESULTS Average coverage depth was ∼760× (median = 600, 99.4% > 100×). Among 93 patients, 18 mutations were identified in 17 cases (18%), including 3 copy number mutations: 2 PMP22 duplications and 1 MPZ duplication. The 2 patients with PMP22 duplication presented with bulbar and respiratory involvement and had absent extremity nerve conductions, leading to axonal diagnosis. Average onset age of these 17 patients was 25 years (2-61 years), vs 45 years for those without genetic discovery. Among those with onset age less than 40 years, the diagnostic yield of targeted NGS approach is high (27%) and cost savings is significant (∼20%). However, the cost savings for patients with late onset age and without family history is not demonstrated. CONCLUSIONS Incorporating copy number analysis in target-enrichment NGS approach improved the efficiency of mutation discovery for chronic, inherited, progressive length-dependent polyneuropathy diagnosis. The new technology is facilitating a simplified genetic diagnostic algorithm utilizing targeted NGS, clinical phenotypes, age at onset, and family history to improve diagnosis efficiency. Our findings prompt a need for updating the current practice parameters and payer guidelines.
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Affiliation(s)
- Wei Wang
- From the Departments of Neurology, Peripheral Nerve Division (W.W., P.J.D., C.J.K.), Department of Health Science Research (C.W., S.B., J.M.E.), Laboratory Medicine and Pathology (D.B.D., E.C.T., P.A.L., Y.W., C.J.K.), Medical Genome Facility (B.W.E., Y.W.), and Medical Genetics (C.J.K., D.B.D.), Mayo Clinic, Rochester, MN; Department of Neurology (W.W.), China-Japan Friendship Hospital, Beijing, China; and Department of Neurology (S.S.S.), Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Chen Wang
- From the Departments of Neurology, Peripheral Nerve Division (W.W., P.J.D., C.J.K.), Department of Health Science Research (C.W., S.B., J.M.E.), Laboratory Medicine and Pathology (D.B.D., E.C.T., P.A.L., Y.W., C.J.K.), Medical Genome Facility (B.W.E., Y.W.), and Medical Genetics (C.J.K., D.B.D.), Mayo Clinic, Rochester, MN; Department of Neurology (W.W.), China-Japan Friendship Hospital, Beijing, China; and Department of Neurology (S.S.S.), Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - D Brian Dawson
- From the Departments of Neurology, Peripheral Nerve Division (W.W., P.J.D., C.J.K.), Department of Health Science Research (C.W., S.B., J.M.E.), Laboratory Medicine and Pathology (D.B.D., E.C.T., P.A.L., Y.W., C.J.K.), Medical Genome Facility (B.W.E., Y.W.), and Medical Genetics (C.J.K., D.B.D.), Mayo Clinic, Rochester, MN; Department of Neurology (W.W.), China-Japan Friendship Hospital, Beijing, China; and Department of Neurology (S.S.S.), Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Erik C Thorland
- From the Departments of Neurology, Peripheral Nerve Division (W.W., P.J.D., C.J.K.), Department of Health Science Research (C.W., S.B., J.M.E.), Laboratory Medicine and Pathology (D.B.D., E.C.T., P.A.L., Y.W., C.J.K.), Medical Genome Facility (B.W.E., Y.W.), and Medical Genetics (C.J.K., D.B.D.), Mayo Clinic, Rochester, MN; Department of Neurology (W.W.), China-Japan Friendship Hospital, Beijing, China; and Department of Neurology (S.S.S.), Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Patrick A Lundquist
- From the Departments of Neurology, Peripheral Nerve Division (W.W., P.J.D., C.J.K.), Department of Health Science Research (C.W., S.B., J.M.E.), Laboratory Medicine and Pathology (D.B.D., E.C.T., P.A.L., Y.W., C.J.K.), Medical Genome Facility (B.W.E., Y.W.), and Medical Genetics (C.J.K., D.B.D.), Mayo Clinic, Rochester, MN; Department of Neurology (W.W.), China-Japan Friendship Hospital, Beijing, China; and Department of Neurology (S.S.S.), Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Bruce W Eckloff
- From the Departments of Neurology, Peripheral Nerve Division (W.W., P.J.D., C.J.K.), Department of Health Science Research (C.W., S.B., J.M.E.), Laboratory Medicine and Pathology (D.B.D., E.C.T., P.A.L., Y.W., C.J.K.), Medical Genome Facility (B.W.E., Y.W.), and Medical Genetics (C.J.K., D.B.D.), Mayo Clinic, Rochester, MN; Department of Neurology (W.W.), China-Japan Friendship Hospital, Beijing, China; and Department of Neurology (S.S.S.), Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Yanhong Wu
- From the Departments of Neurology, Peripheral Nerve Division (W.W., P.J.D., C.J.K.), Department of Health Science Research (C.W., S.B., J.M.E.), Laboratory Medicine and Pathology (D.B.D., E.C.T., P.A.L., Y.W., C.J.K.), Medical Genome Facility (B.W.E., Y.W.), and Medical Genetics (C.J.K., D.B.D.), Mayo Clinic, Rochester, MN; Department of Neurology (W.W.), China-Japan Friendship Hospital, Beijing, China; and Department of Neurology (S.S.S.), Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Saurabh Baheti
- From the Departments of Neurology, Peripheral Nerve Division (W.W., P.J.D., C.J.K.), Department of Health Science Research (C.W., S.B., J.M.E.), Laboratory Medicine and Pathology (D.B.D., E.C.T., P.A.L., Y.W., C.J.K.), Medical Genome Facility (B.W.E., Y.W.), and Medical Genetics (C.J.K., D.B.D.), Mayo Clinic, Rochester, MN; Department of Neurology (W.W.), China-Japan Friendship Hospital, Beijing, China; and Department of Neurology (S.S.S.), Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Jared M Evans
- From the Departments of Neurology, Peripheral Nerve Division (W.W., P.J.D., C.J.K.), Department of Health Science Research (C.W., S.B., J.M.E.), Laboratory Medicine and Pathology (D.B.D., E.C.T., P.A.L., Y.W., C.J.K.), Medical Genome Facility (B.W.E., Y.W.), and Medical Genetics (C.J.K., D.B.D.), Mayo Clinic, Rochester, MN; Department of Neurology (W.W.), China-Japan Friendship Hospital, Beijing, China; and Department of Neurology (S.S.S.), Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Steven S Scherer
- From the Departments of Neurology, Peripheral Nerve Division (W.W., P.J.D., C.J.K.), Department of Health Science Research (C.W., S.B., J.M.E.), Laboratory Medicine and Pathology (D.B.D., E.C.T., P.A.L., Y.W., C.J.K.), Medical Genome Facility (B.W.E., Y.W.), and Medical Genetics (C.J.K., D.B.D.), Mayo Clinic, Rochester, MN; Department of Neurology (W.W.), China-Japan Friendship Hospital, Beijing, China; and Department of Neurology (S.S.S.), Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Peter J Dyck
- From the Departments of Neurology, Peripheral Nerve Division (W.W., P.J.D., C.J.K.), Department of Health Science Research (C.W., S.B., J.M.E.), Laboratory Medicine and Pathology (D.B.D., E.C.T., P.A.L., Y.W., C.J.K.), Medical Genome Facility (B.W.E., Y.W.), and Medical Genetics (C.J.K., D.B.D.), Mayo Clinic, Rochester, MN; Department of Neurology (W.W.), China-Japan Friendship Hospital, Beijing, China; and Department of Neurology (S.S.S.), Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Christopher J Klein
- From the Departments of Neurology, Peripheral Nerve Division (W.W., P.J.D., C.J.K.), Department of Health Science Research (C.W., S.B., J.M.E.), Laboratory Medicine and Pathology (D.B.D., E.C.T., P.A.L., Y.W., C.J.K.), Medical Genome Facility (B.W.E., Y.W.), and Medical Genetics (C.J.K., D.B.D.), Mayo Clinic, Rochester, MN; Department of Neurology (W.W.), China-Japan Friendship Hospital, Beijing, China; and Department of Neurology (S.S.S.), Perelman School of Medicine, University of Pennsylvania, Philadelphia.
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14
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The role of combined SNV and CNV burden in patients with distal symmetric polyneuropathy. Genet Med 2015; 18:443-51. [PMID: 26378787 DOI: 10.1038/gim.2015.124] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 07/27/2015] [Indexed: 01/10/2023] Open
Abstract
PURPOSE Charcot-Marie-Tooth (CMT) disease is a heterogeneous group of genetic disorders of the peripheral nervous system. Copy-number variants (CNVs) contribute significantly to CMT, as duplication of PMP22 underlies the majority of CMT1 cases. We hypothesized that CNVs and/or single-nucleotide variants (SNVs) might exist in patients with CMT with an unknown molecular genetic etiology. METHODS Two hundred patients with CMT, negative for both SNV mutations in several CMT genes and for CNVs involving PMP22, were screened for CNVs by high-resolution oligonucleotide array comparative genomic hybridization. Whole-exome sequencing was conducted on individuals with rare, potentially pathogenic CNVs. RESULTS Putatively causative CNVs were identified in five subjects (~2.5%); four of the five map to known neuropathy genes. Breakpoint sequencing revealed Alu-Alu-mediated junctions as a predominant contributor. Exome sequencing identified MFN2 SNVs in two of the individuals. CONCLUSION Neuropathy-associated CNV outside of the PMP22 locus is rare in CMT. Nevertheless, there is potential clinical utility in testing for CNVs and exome sequencing in CMT cases negative for the CMT1A duplication. These findings suggest that complex phenotypes including neuropathy can potentially be caused by a combination of SNVs and CNVs affecting more than one disease-associated locus and contributing to a mutational burden.Genet Med 18 5, 443-451.
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15
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Capponi S, Geroldi A, Pezzini I, Gulli R, Ciotti P, Ursino G, Lamp M, Reni L, Schenone A, Grandis M, Mandich P, Bellone E. Contribution of copy number variations in CMT1X: a retrospective study. Eur J Neurol 2015; 22:406-9. [PMID: 24724718 DOI: 10.1111/ene.12434] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 03/06/2014] [Indexed: 11/30/2022]
Abstract
BACKGROUND AND PURPOSE Charcot-Marie-Tooth disease type 1X (CMT1X) is an X-linked dominant hereditary motor-sensory peripheral neuropathy, which results from mutations in the Gap Junction B1 (GJB1) gene. In a few cases, gene deletions have been linked to the disease, but their relative contribution in the pathogenesis of CMT1X has not been assessed yet. Herein a retrospective study to establish the incidence of gene deletions is described. METHODS Copy number variation analysis was performed by multiplex ligation-dependent probe amplification, whilst the breakpoints were defined by Sanger sequencing. RESULTS A novel GJB1 deletion was identified in a family presenting with a classical CMT1X phenotype. The rearrangement includes the coding and the regulatory regions of GJB1. CONCLUSIONS GJB1 deletions appear to be a rare but not insignificant cause of CMT1X and are associated with a typical disease phenotype. Accordingly, patients negative for point mutations whose pedigree and clinical records strongly suggest the possibility of CMT1X should be tested for GJB1 copy number variations.
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Affiliation(s)
- S Capponi
- Section of Medical Genetics, Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health (DINOGMI), University of Genoa, Genoa, Italy
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16
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Copy number variations in a population-based study of Charcot-Marie-Tooth disease. BIOMED RESEARCH INTERNATIONAL 2015; 2015:960404. [PMID: 25648254 PMCID: PMC4306395 DOI: 10.1155/2015/960404] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 12/13/2014] [Indexed: 12/14/2022]
Abstract
Copy number variations (CNVs) are important in relation to diversity and evolution but can sometimes cause disease. The most common genetic cause of the inherited peripheral neuropathy Charcot-Marie-Tooth disease is the PMP22 duplication; otherwise, CNVs have been considered rare. We investigated CNVs in a population-based sample of Charcot-Marie-Tooth (CMT) families. The 81 CMT families had previously been screened for the PMP22 duplication and point mutations in 51 peripheral neuropathy genes, and a genetic cause was identified in 37 CMT families (46%). Index patients from the 44 CMT families with an unknown genetic diagnosis were analysed by whole-genome array comparative genomic hybridization to investigate the entire genome for larger CNVs and multiplex ligation-dependent probe amplification to detect smaller intragenomic CNVs in MFN2 and MPZ. One patient had the pathogenic PMP22 duplication not detected by previous methods. Three patients had potentially pathogenic CNVs in the CNTNAP2, LAMA2, or SEMA5A, that is, genes related to neuromuscular or neurodevelopmental disease. Genotype and phenotype correlation indicated likely pathogenicity for the LAMA2 CNV, whereas the CNTNAP2 and SEMA5A CNVs remained potentially pathogenic. Except the PMP22 duplication, disease causing CNVs are rare but may cause CMT in about 1% (95% CI 0–7%) of the Norwegian CMT families.
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17
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Yin X, Kiryu-Seo S, Kidd GJ, Feltri ML, Wrabetz L, Trapp BD. Proteolipid protein cannot replace P0 protein as the major structural protein of peripheral nervous system myelin. Glia 2014; 63:66-77. [PMID: 25066805 DOI: 10.1002/glia.22733] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 07/14/2014] [Indexed: 11/10/2022]
Abstract
The central nervous system (CNS) of terrestrial vertebrates underwent a prominent molecular change when proteolipid protein (PLP) replaced P0 protein as the most abundant protein of CNS myelin. However, PLP did not replace P0 in peripheral nervous system (PNS) myelin. To investigate the possible consequences of a PLP to P0 shift in PNS myelin, we engineered mice to express PLP instead of P0 in PNS myelin (PLP-PNS mice). PLP-PNS mice had severe neurological disabilities and died between 3 and 6 months of age. Schwann cells in sciatic nerves from PLP-PNS mice sorted axons into one-to-one relationships but failed to form myelin internodes. Mice with equal amounts of P0 and PLP had normal PNS myelination and lifespans similar to wild-type (WT) mice. When PLP was overexpressed with one copy of the P0 gene, sciatic nerves were hypomyelinated; mice displayed motor deficits, but had normal lifespans. These data support the hypothesis that while PLP can co-exist with P0 in PNS myelin, PLP cannot replace P0 as the major structural protein of PNS myelin.
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Affiliation(s)
- Xinghua Yin
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
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18
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Harel T, Lupski J. Charcot-Marie-Tooth disease and pathways to molecular based therapies. Clin Genet 2014; 86:422-31. [DOI: 10.1111/cge.12393] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 03/27/2014] [Accepted: 03/28/2014] [Indexed: 01/31/2023]
Affiliation(s)
- T. Harel
- Department of Molecular and Human Genetics; Baylor College of Medicine; Houston TX USA
| | - J.R. Lupski
- Department of Molecular and Human Genetics; Baylor College of Medicine; Houston TX USA
- Department of Pediatrics; Baylor College of Medicine; Houston TX USA
- Texas Children's Hospital; Houston TX USA
- Human Genome Sequencing Center; Baylor College of Medicine; Houston TX USA
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19
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Ishiura H, Takahashi Y, Hayashi T, Saito K, Furuya H, Watanabe M, Murata M, Suzuki M, Sugiura A, Sawai S, Shibuya K, Ueda N, Ichikawa Y, Kanazawa I, Goto J, Tsuji S. Molecular epidemiology and clinical spectrum of hereditary spastic paraplegia in the Japanese population based on comprehensive mutational analyses. J Hum Genet 2014; 59:163-72. [PMID: 24451228 DOI: 10.1038/jhg.2013.139] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 11/16/2013] [Accepted: 11/29/2013] [Indexed: 12/12/2022]
Abstract
Hereditary spastic paraplegia (HSP) is one of the most genetically heterogeneous neurodegenerative disorders characterized by progressive spasticity and pyramidal weakness of lower limbs. Because >30 causative genes have been identified, screening of multiple genes is required for establishing molecular diagnosis of individual patients with HSP. To elucidate molecular epidemiology of HSP in the Japanese population, we have conducted mutational analyses of 16 causative genes of HSP (L1CAM, PLP1, ATL1, SPAST, CYP7B1, NIPA1, SPG7, KIAA0196, KIF5A, HSPD1, BSCL2, SPG11, SPG20, SPG21, REEP1 and ZFYVE27) using resequencing microarrays, array-based comparative genomic hybridization and Sanger sequencing. The mutational analysis of 129 Japanese patients revealed 49 mutations in 46 patients, 32 of which were novel. Molecular diagnosis was accomplished for 67.3% (33/49) of autosomal dominant HSP patients. Even among sporadic HSP patients, mutations were identified in 11.1% (7/63) of them. The present study elucidated the molecular epidemiology of HSP in the Japanese population and further broadened the mutational and clinical spectra of HSP.
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Affiliation(s)
- Hiroyuki Ishiura
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yuji Takahashi
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Toshihiro Hayashi
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Kayoko Saito
- Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, Japan
| | - Hirokazu Furuya
- Department of Neurology, Neuro-Muscular Center, National Omuta Hospital, Fukuoka, Japan
| | - Mitsunori Watanabe
- Department of Neurology, Institute of Brain Science, Hirosaki University Graduate School of Medicine, Aomori, Japan
| | - Miho Murata
- Department of Neurology, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Mikiya Suzuki
- Department of Neurology, Higashisaitama Hospital, National Hospital Organization, Saitama, Japan
| | - Akira Sugiura
- Department of Neurology, Shizuoka Institute of Epilepsy and Neurological Disorders, Shizuoka, Japan
| | - Setsu Sawai
- 1] Department of Molecular Diagnosis, Graduate School of Medicine, Chiba University, Chiba, Japan [2] Division of Laboratory Medicine and Clinical Genetics, Chiba University Hospital, Chiba, Japan
| | - Kazumoto Shibuya
- Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Naohisa Ueda
- 1] Department of Neurology, Chigasaki Municipal Hospital, Kanagawa, Japan [2] Department of Neurology, Yokohama City University School of Medicine, Kanagawa, Japan
| | - Yaeko Ichikawa
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Ichiro Kanazawa
- Graduate School, International University of Health and Welfare, Tokyo, Japan
| | - Jun Goto
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Shoji Tsuji
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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Exonic duplication CNV of NDRG1 associated with autosomal-recessive HMSN-Lom/CMT4D. Genet Med 2013; 16:386-394. [PMID: 24136616 DOI: 10.1038/gim.2013.155] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 08/27/2013] [Indexed: 01/28/2023] Open
Abstract
PURPOSE Copy-number variations as a mutational mechanism contribute significantly to human disease. Approximately one-half of the patients with Charcot-Marie-Tooth (CMT) disease have a 1.4 Mb duplication copy-number variation as the cause of their neuropathy. However, non-CMT1A neuropathy patients rarely have causative copy-number variations, and to date, autosomal-recessive disease has not been associated with copy-number variation as a mutational mechanism. METHODS We performed Agilent 8 × 60 K array comparative genomic hybridization on DNA from 12 recessive Turkish families with CMT disease. Additional molecular studies were conducted to detect breakpoint junctions and to evaluate gene expression levels in a family in which we detected an intragenic duplication copy-number variation. RESULTS We detected an ~6.25 kb homozygous intragenic duplication in NDRG1, a gene known to be causative for recessive HMSNL/CMT4D, in three individuals from a Turkish family with CMT neuropathy. Further studies showed that this intragenic copy-number variation resulted in a homozygous duplication of exons 6-8 that caused decreased mRNA expression of NDRG1. CONCLUSION Exon-focused high-resolution array comparative genomic hybridization enables the detection of copy-number variation carrier states in recessive genes, particularly small copy-number variations encompassing or disrupting single genes. In families for whom a molecular diagnosis has not been elucidated by conventional clinical assays, an assessment for copy-number variations in known CMT genes might be considered.
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Speevak MD, Farrell SA. Charcot-Marie-Tooth 1B caused by expansion of a familial myelin protein zero (MPZ) gene duplication. Eur J Med Genet 2013; 56:566-9. [PMID: 23811036 DOI: 10.1016/j.ejmg.2013.06.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 06/03/2013] [Indexed: 10/26/2022]
Abstract
Charcot-Marie-Tooth (CMT) disease is a group of hereditary disorders affecting the motor and sensory nerves of the peripheral nervous system. CMT patterns of inheritance include dominant, recessive, and X-linked disorders. Charcot-Marie-Tooth disease, type 1B (CMT1B, OMIM 118200) is an autosomal dominant neuropathy caused by mutations in myelin protein zero (MPZ, OMIM 159440), a structural protein of peripheral myelin. Most causative MPZ mutations are missense sequence variants; however, recent clinical reports have described cases of CMT1B caused by increased dosage of the MPZ gene, with over-expression of the MPZ protein suspected to be causative of the disorder. We report an unusual case of early onset de novo CMT1B, caused by amplification of a familial, apparently benign, MPZ duplication.
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Affiliation(s)
- Marsha D Speevak
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada; Division of Genetics, Trillium Health Partners, Credit Valley Hospital, 2200 Eglinton Ave., West, Mississauga, Ontario, Canada L5M 2N1.
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CFTR-deficient pigs display peripheral nervous system defects at birth. Proc Natl Acad Sci U S A 2013; 110:3083-8. [PMID: 23382208 DOI: 10.1073/pnas.1222729110] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Peripheral nervous system abnormalities, including neuropathy, have been reported in people with cystic fibrosis. These abnormalities have largely been attributed to secondary manifestations of the disease. We tested the hypothesis that disruption of the cystic fibrosis transmembrane conductance regulator (CFTR) gene directly influences nervous system function by studying newborn CFTR(-/-) pigs. We discovered CFTR expression and activity in Schwann cells, and loss of CFTR caused ultrastructural myelin sheath abnormalities similar to those in known neuropathies. Consistent with neuropathic changes, we found increased transcripts for myelin protein zero, a gene that, when mutated, can cause axonal and/or demyelinating neuropathy. In addition, axon density was reduced and conduction velocities of the trigeminal and sciatic nerves were decreased. Moreover, in vivo auditory brainstem evoked potentials revealed delayed conduction of the vestibulocochlear nerve. Our data suggest that loss of CFTR directly alters Schwann cell function and that some nervous system defects in people with cystic fibrosis are likely primary.
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Azzedine H, Senderek J, Rivolta C, Chrast R. Molecular genetics of charcot-marie-tooth disease: from genes to genomes. Mol Syndromol 2012; 3:204-14. [PMID: 23293578 DOI: 10.1159/000343487] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Charcot-Marie-Tooth disease (CMT) is a heterogeneous group of disorders of the peripheral nervous system, mainly characterized by distal muscle weakness and atrophy leading to motor handicap. With an estimated prevalence of 1 in 2,500, this condition is one of the most commonly inherited neurological disorders. Mutations in more than 30 genes affecting glial and/or neuronal functions have been associated with different forms of CMT leading to a substantial improvement in diagnostics of the disease and in the understanding of implicated pathophysiological mechanisms. However, recent data from systematic genetic screening performed in large cohorts of CMT patients indicated that molecular diagnosis could be established only in ∼50-70% of them, suggesting that additional genes are involved in this disease. In addition to providing an overview of genetic and functional data concerning various CMT forms, this review focuses on recent data generated through the use of highly parallel genetic technologies (SNP chips, sequence capture and next-generation DNA sequencing) in CMT families, and the current and future impact of these technologies on gene discovery and diagnostics of CMTs.
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Affiliation(s)
- H Azzedine
- Department of Medical Genetics, University of Lausanne, Lausanne, Switzerland
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Azzedine H, Senderek J, Rivolta C, Chrast R. Molecular genetics of charcot-marie-tooth disease: from genes to genomes. Mol Syndromol 2012. [PMID: 23293578 DOI: 10.1159/000343487/msy-0003-0204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Charcot-Marie-Tooth disease (CMT) is a heterogeneous group of disorders of the peripheral nervous system, mainly characterized by distal muscle weakness and atrophy leading to motor handicap. With an estimated prevalence of 1 in 2,500, this condition is one of the most commonly inherited neurological disorders. Mutations in more than 30 genes affecting glial and/or neuronal functions have been associated with different forms of CMT leading to a substantial improvement in diagnostics of the disease and in the understanding of implicated pathophysiological mechanisms. However, recent data from systematic genetic screening performed in large cohorts of CMT patients indicated that molecular diagnosis could be established only in ∼50-70% of them, suggesting that additional genes are involved in this disease. In addition to providing an overview of genetic and functional data concerning various CMT forms, this review focuses on recent data generated through the use of highly parallel genetic technologies (SNP chips, sequence capture and next-generation DNA sequencing) in CMT families, and the current and future impact of these technologies on gene discovery and diagnostics of CMTs.
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Affiliation(s)
- H Azzedine
- Department of Medical Genetics, University of Lausanne, Lausanne, Switzerland
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Nadra K, Médard JJ, Quignodon L, Verheijen MHG, Desvergne B, Chrast R. Epineurial adipocytes are dispensable for Schwann cell myelination. J Neurochem 2012; 123:662-7. [PMID: 22849425 DOI: 10.1111/j.1471-4159.2012.07896.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 07/11/2012] [Accepted: 07/12/2012] [Indexed: 12/18/2022]
Abstract
Previous clinical observations and data from mouse models with defects in lipid metabolism suggested that epineurial adipocytes may play a role in peripheral nervous system myelination. We have used adipocyte-specific Lpin1 knockout mice to characterize the consequences of the presence of impaired epineurial adipocytes on the myelinating peripheral nerve. Our data revealed that the capacity of Schwann cells to establish myelin, and the functional properties of peripheral nerves, were not affected by compromised epineurial adipocytes in adipocyte-specific Lpin1 knockout mice. To evaluate the possibility that Lpin1-negative adipocytes are still able to support endoneurial Schwann cells, we also characterized sciatic nerves from mice carrying epiblast-specific deletion of peroxisome proliferator-activated receptor gamma, which develop general lipoatrophy. Interestingly, even the complete loss of adipocytes in the epineurium of peroxisome proliferator-activated receptor gamma knockout mice did not lead to detectable defects in Schwann cell myelination. However, probably as a consequence of their hyperglycemia, these mice have reduced nerve conduction velocity, thus mimicking the phenotype observed under diabetic condition. Together, our data indicate that while adipocytes, as regulators of lipid and glucose homeostasis, play a role in nerve function, their presence in epineurium is not essential for establishment or maintenance of proper myelin.
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Affiliation(s)
- Karim Nadra
- Department of Medical Genetics, University of Lausanne, Lausanne, Switzerland
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Neural and molecular features on Charcot-Marie-Tooth disease plasticity and therapy. Neural Plast 2012; 2012:171636. [PMID: 22745917 PMCID: PMC3382403 DOI: 10.1155/2012/171636] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 04/16/2012] [Indexed: 12/21/2022] Open
Abstract
In the peripheral nervous system disorders plasticity is related to changes on the axon and Schwann cell biology, and the synaptic formations and connections, which could be also a focus for therapeutic research. Charcot-Marie-Tooth disease (CMT) represents a large group of inherited peripheral neuropathies that involve mainly both motor and sensory nerves and induce muscular atrophy and weakness. Genetic analysis has identified several pathways and molecular mechanisms involving myelin structure and proper nerve myelination, transcriptional regulation, protein turnover, vesicle trafficking, axonal transport and mitochondrial dynamics. These pathogenic mechanisms affect the continuous signaling and dialogue between the Schwann cell and the axon, having as final result the loss of myelin and nerve maintenance; however, some late onset axonal CMT neuropathies are a consequence of Schwann cell specific changes not affecting myelin. Comprehension of molecular pathways involved in Schwann cell-axonal interactions is likely not only to increase the understanding of nerve biology but also to identify the molecular targets and cell pathways to design novel therapeutic approaches for inherited neuropathies but also for most common peripheral neuropathies. These approaches should improve the plasticity of the synaptic connections at the neuromuscular junction and regenerate cell viability based on improving myelin and axon interaction.
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Fledrich R, Stassart RM, Sereda MW. Murine therapeutic models for Charcot-Marie-Tooth (CMT) disease. Br Med Bull 2012; 102:89-113. [PMID: 22551516 DOI: 10.1093/bmb/lds010] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
INTRODUCTION OR BACKGROUND Charcot-Marie-Tooth (CMT) disease represents a broad group of inherited motor and sensory neuropathies which can originate from various genetic aberrations, e.g. mutations, deletions and duplications. SOURCES OF DATA We performed a literature review on murine animal models of CMT disease with regard to experimental therapeutic approaches. Hereby, we focussed on the demyelinating subforms of CMT (CMT1). PubMed items were CMT, animal model, demyelination and therapy. AREAS OF AGREEMENT Patients affected by CMT suffer from slowly progressive, distally pronounced muscle atrophy caused by an axonal loss. The disease severity is highly variable and impairments may result in wheelchair boundness. No therapy is available yet. AREAS OF CONTROVERSY Numerous rodent models for the various CMT subtypes are available today. The selection of the correct animal model for the specific CMT subtype provides an important prerequisite for the successful translation of experimental findings in patients. GROWING POINTS Despite more than 20 years of remarkable progress in CMT research, the disease is still left untreatable. There is a growing number of experimental therapeutic strategies that may be translated into future clinical trials in patients with CMT. AREAS TIMELY FOR DEVELOPING RESEARCH The slow disease progression and insensitive outcome measures hamper clinical therapy trials in CMT. Biomarkers may provide powerful tools to monitor therapeutic efficacy. Recently, we have shown that transcriptional profiling can be utilized to assess and predict the disease severity in a transgenic rat model and in affected humans.
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Affiliation(s)
- Robert Fledrich
- Research Group 'Molecular and Translational Neurology', Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
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