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Larson AA, Baker PR, Milev MP, Press CA, Sokol RJ, Cox MO, Lekostaj JK, Stence AA, Bossler AD, Mueller JM, Prematilake K, Tadjo TF, Williams CA, Sacher M, Moore SA. TRAPPC11 and GOSR2 mutations associate with hypoglycosylation of α-dystroglycan and muscular dystrophy. Skelet Muscle 2018; 8:17. [PMID: 29855340 PMCID: PMC5984345 DOI: 10.1186/s13395-018-0163-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 05/16/2018] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Transport protein particle (TRAPP) is a supramolecular protein complex that functions in localizing proteins to the Golgi compartment. The TRAPPC11 subunit has been implicated in muscle disease by virtue of homozygous and compound heterozygous deleterious mutations being identified in individuals with limb girdle muscular dystrophy and congenital muscular dystrophy. It remains unclear how this protein leads to muscle disease. Furthermore, a role for this protein, or any other membrane trafficking protein, in the etiology of the dystroglycanopathy group of muscular dystrophies has yet to be found. Here, using a multidisciplinary approach including genetics, immunofluorescence, western blotting, and live cell analysis, we implicate both TRAPPC11 and another membrane trafficking protein, GOSR2, in α-dystroglycan hypoglycosylation. CASE PRESENTATION Subject 1 presented with severe epileptic episodes and subsequent developmental deterioration. Upon clinical evaluation she was found to have brain, eye, and liver abnormalities. Her serum aminotransferases and creatine kinase were abnormally high. Subjects 2 and 3 are siblings from a family unrelated to subject 1. Both siblings displayed hypotonia, muscle weakness, low muscle bulk, and elevated creatine kinase levels. Subject 3 also developed a seizure disorder. Muscle biopsies from subjects 1 and 3 were severely dystrophic with abnormal immunofluorescence and western blotting indicative of α-dystroglycan hypoglycosylation. Compound heterozygous mutations in TRAPPC11 were identified in subject 1: c.851A>C and c.965+5G>T. Cellular biological analyses on fibroblasts confirmed abnormal membrane trafficking. Subject 3 was found to have compound heterozygous mutations in GOSR2: c.430G>T and c.2T>G. Cellular biological analyses on fibroblasts from subject 3 using two different model cargo proteins did not reveal defects in protein transport. No mutations were found in any of the genes currently known to cause dystroglycanopathy in either individual. CONCLUSION Recessive mutations in TRAPPC11 and GOSR2 are associated with congenital muscular dystrophy and hypoglycosylation of α-dystroglycan. This is the first report linking membrane trafficking proteins to dystroglycanopathy and suggests that these genes should be considered in the diagnostic evaluation of patients with congenital muscular dystrophy and dystroglycanopathy.
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Affiliation(s)
- Austin A. Larson
- Department of Pediatrics, University of Colorado School of Medicine and Children’s Hospital Colorado, Aurora, CO USA
| | - Peter R. Baker
- Department of Pediatrics, University of Colorado School of Medicine and Children’s Hospital Colorado, Aurora, CO USA
| | | | - Craig A. Press
- Department of Pediatrics, University of Colorado School of Medicine and Children’s Hospital Colorado, Aurora, CO USA
| | - Ronald J. Sokol
- Department of Pediatrics, University of Colorado School of Medicine and Children’s Hospital Colorado, Aurora, CO USA
| | - Mary O. Cox
- Department of Pathology Carver College of Medicine, The University of Iowa, Iowa City, IA USA
| | - Jacqueline K. Lekostaj
- Department of Pathology Carver College of Medicine, The University of Iowa, Iowa City, IA USA
| | - Aaron A. Stence
- Department of Pathology Carver College of Medicine, The University of Iowa, Iowa City, IA USA
| | - Aaron D. Bossler
- Department of Pathology Carver College of Medicine, The University of Iowa, Iowa City, IA USA
| | - Jennifer M. Mueller
- Division of Genetics and Metabolism, University of Florida College of Medicine, Gainesville, FL USA
| | | | | | - Charles A. Williams
- Division of Genetics and Metabolism, University of Florida College of Medicine, Gainesville, FL USA
| | - Michael Sacher
- Department of Biology, Concordia University, Montreal, Canada
- Department of Anatomy and Cell Biology, McGill University, Montreal, Canada
| | - Steven A. Moore
- Department of Pathology Carver College of Medicine, The University of Iowa, Iowa City, IA USA
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Genetics and mechanisms leading to human cortical malformations. Semin Cell Dev Biol 2018; 76:33-75. [DOI: 10.1016/j.semcdb.2017.09.031] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 09/21/2017] [Accepted: 09/21/2017] [Indexed: 02/06/2023]
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Kanagawa M, Toda T. Ribitol-phosphate—a newly identified posttranslational glycosylation unit in mammals: structure, modification enzymes and relationship to human diseases. J Biochem 2018; 163:359-369. [DOI: 10.1093/jb/mvy020] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 01/23/2018] [Indexed: 01/05/2023] Open
Affiliation(s)
- Motoi Kanagawa
- Division of Molecular Brain Science, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
| | - Tatsushi Toda
- Division of Molecular Brain Science, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
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Blaeser A, Awano H, Lu P, Lu QL. Distinct expression of functionally glycosylated alpha-dystroglycan in muscle and non-muscle tissues of FKRP mutant mice. PLoS One 2018; 13:e0191016. [PMID: 29320543 PMCID: PMC5761899 DOI: 10.1371/journal.pone.0191016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 12/27/2017] [Indexed: 01/06/2023] Open
Abstract
The glycosylation of alpha-dystroglycan (α-DG) is crucial in maintaining muscle cell membrane integrity. Dystroglycanopathies are identified by the loss of this glycosylation leading to a breakdown of muscle cell membrane integrity and eventual degeneration. However, a small portion of fibers expressing functionally glycosylated α-DG (F-α-DG) (revertant fibers, RF) have been identified. These fibers are generally small in size, centrally nucleated and linked to regenerating fibers. Examination of different muscles have shown various levels of RFs but it is unclear the extent of which they are present. Here we do a body-wide examination of muscles from the FKRP-P448L mutant mouse for the prevalence of RFs. We have identified great variation in the distribution of RF in different muscles and tissues. Triceps shows a large increase in RFs and together with centrally nucleated fibers whereas the pectoralis shows a reduction in revertant but increase in centrally nucleated fibers from 6 weeks to 6 months of age. We have also identified that the sciatic nerve with near normal levels of F-α-DG in the P448Lneo- mouse with reduced levels in the P448Lneo+ and absent in LARGEmyd. The salivary gland of LARGEmyd mice expresses high levels of F-α-DG. Interestingly the same glands in the P448Lneo-and to a lesser degree in P448Lneo+ also maintain considerable amount of F-α-DG, indicating the non-proliferating epithelial cells have a molecular setting permitting glycosylation.
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Affiliation(s)
- Anthony Blaeser
- McColl-Lockwood Laboratory for Muscular Dystrophy Research, Carolinas HealthCare System, Charlotte, North Carolina, United States of America
- * E-mail: (QL); (AB)
| | - Hiroyuki Awano
- McColl-Lockwood Laboratory for Muscular Dystrophy Research, Carolinas HealthCare System, Charlotte, North Carolina, United States of America
| | - Pei Lu
- McColl-Lockwood Laboratory for Muscular Dystrophy Research, Carolinas HealthCare System, Charlotte, North Carolina, United States of America
| | - Qi-Long Lu
- McColl-Lockwood Laboratory for Muscular Dystrophy Research, Carolinas HealthCare System, Charlotte, North Carolina, United States of America
- * E-mail: (QL); (AB)
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55
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Goffinet AM. The evolution of cortical development: the synapsid-diapsid divergence. Development 2017; 144:4061-4077. [PMID: 29138289 DOI: 10.1242/dev.153908] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The cerebral cortex covers the rostral part of the brain and, in higher mammals and particularly humans, plays a key role in cognition and consciousness. It is populated with neuronal cell bodies distributed in radially organized layers. Understanding the common and lineage-specific molecular mechanisms that orchestrate cortical development and evolution are key issues in neurobiology. During evolution, the cortex appeared in stem amniotes and evolved divergently in two main branches of the phylogenetic tree: the synapsids (which led to present day mammals) and the diapsids (reptiles and birds). Comparative studies in organisms that belong to those two branches have identified some common principles of cortical development and organization that are possibly inherited from stem amniotes and regulated by similar molecular mechanisms. These comparisons have also highlighted certain essential features of mammalian cortices that are absent or different in diapsids and that probably evolved after the synapsid-diapsid divergence. Chief among these is the size and multi-laminar organization of the mammalian cortex, and the propensity to increase its area by folding. Here, I review recent data on cortical neurogenesis, neuronal migration and cortical layer formation and folding in this evolutionary perspective, and highlight important unanswered questions for future investigation.
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Affiliation(s)
- Andre M Goffinet
- University of Louvain, Avenue Mounier, 73 Box B1.73.16, B1200 Brussels, Belgium
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56
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Abstract
INTRODUCTION Fukuyama congenital muscular dystrophy (FCMD), caused by fukutin mutations, is the most common form of Japanese CMD. We followed a Japanese CMD sibship without fukutin mutation, and herein identified new FKRP mutations causing MDC1C rarely reported in Oriental countries. PATIENTS Two affected siblings, individuals 1 (I-1, male) and 2 (I-2, female), were born uneventfully to unaffected, non-consanguineous parents. Severe hypotonia was soon apparent and serum CK levels were elevated: I-1: 1025 IU/L (normal range <130 IU/L) and I-2: 5350 IU/L. I-1 had neither shown head control, nor said any words until he died of pneumonia at the age of 23months. I-2 learned to sit at 4years and 10months and spoke sentences at 6years and 5months. She had received respiratory support since 9years of age and died at 22years. Both showed a low-density area in the cerebral white matter on CT. MRI of I-2 revealed diffuse hyperintensity in the cerebral white matter on T2-WI, polymicrogyria over the frontal and parietal lobes, and disorganized folia and cysts in the cerebellum. METHODS AND RESULTS Next generation and Sanger sequencing were performed for I-2. Heterozygous FKRP mutations were identified in exon 4: c.1167_1168delGC, p.Gly391Leufs∗72 and c.501_502GT>CC, p.Arg167Ser, p.Cys168Arg. DISCUSSION Recently, fukutin and FKRP were identified as sequentially acting ribitol 5-phosphate transferases involved in the post-translational modification of α-dystroglycan. This may explain the clinical similarities between the two disorders.
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57
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Van Ry PM, Fontelonga TM, Barraza-Flores P, Sarathy A, Nunes AM, Burkin DJ. ECM-Related Myopathies and Muscular Dystrophies: Pros and Cons of Protein Therapies. Compr Physiol 2017; 7:1519-1536. [PMID: 28915335 DOI: 10.1002/cphy.c150033] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Extracellular matrix (ECM) myopathies and muscular dystrophies are a group of genetic diseases caused by mutations in genes encoding proteins that provide critical links between muscle cells and the extracellular matrix. These include structural proteins of the ECM, muscle cell receptors, enzymes, and intracellular proteins. Loss of adhesion within the myomatrix results in progressive muscle weakness. For many ECM muscular dystrophies, symptoms can occur any time after birth and often result in reduced life expectancy. There are no cures for the ECM-related muscular dystrophies and treatment options are limited to palliative care. Several therapeutic approaches have been explored to treat muscular dystrophies including gene therapy, gene editing, exon skipping, embryonic, and adult stem cell therapy, targeting genetic modifiers, modulating inflammatory responses, or preventing muscle degeneration. Recently, protein therapies that replace components of the defective myomatrix or enhance muscle and/or extracellular matrix integrity and function have been explored. Preclinical studies for many of these biologics have been promising in animal models of these muscle diseases. This review aims to summarize the ECM muscular dystrophies for which protein therapies are being developed and discuss the exciting potential and possible limitations of this approach for treating this family of devastating genetic muscle diseases. © 2017 American Physiological Society. Compr Physiol 7:1519-1536, 2017.
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Affiliation(s)
- Pam M Van Ry
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Tatiana M Fontelonga
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Pamela Barraza-Flores
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Apurva Sarathy
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Andreia M Nunes
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada, USA.,Departamento de Biologia Animal, Centro de Ecologia, Evolucao e Alteracoes Ambientais, Faculdade de Ciencias, Universidade de Lisboa, Lisbon, Portugal
| | - Dean J Burkin
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada, USA
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58
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Manya H, Endo T. Glycosylation with ribitol-phosphate in mammals: New insights into the O-mannosyl glycan. Biochim Biophys Acta Gen Subj 2017; 1861:2462-2472. [PMID: 28711406 DOI: 10.1016/j.bbagen.2017.06.024] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 06/23/2017] [Accepted: 06/26/2017] [Indexed: 01/03/2023]
Abstract
BACKGROUND O-mannosyl glycans have been found in a limited number of glycoproteins of the brain, nerves, and skeletal muscles, particularly in α-dystroglycan (α-DG). Defects in O-mannosyl glycan on α-DG are the primary cause of a group of congenital muscular dystrophies, which are collectively termed α-dystroglycanopathy. Recent studies have revealed various O-mannosyl glycan structures, which can be classified as core M1, core M2, and core M3 glycans. Although many dystroglycanopathy genes are involved in core M3 processing, the structure and biosynthesis of core M3 glycan remains only partially understood. SCOPE OF REVIEW This review presents recent findings about the structure, biosynthesis, and pathology of O-mannosyl glycans. MAJOR CONCLUSIONS Recent studies have revealed that the entire structure of core M3 glycan, including ribitol-5-phosphate, is a novel structure in mammals; its unique biosynthetic pathway has been elucidated by the identification of new causative genes for α-dystroglycanopathies and their functions. GENERAL SIGNIFICANCE O-mannosyl glycan has a novel, unique structure that is important for the maintenance of brain and muscle functions. These findings have opened up a new field in glycoscience. These studies will further contribute to the understanding of the pathomechanism of α-dystroglycanopathy and the development of glycotherapeutics. This article is part of a Special Issue entitled Neuro-glycoscience, edited by Kenji Kadomatsu and Hiroshi Kitagawa.
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Affiliation(s)
- Hiroshi Manya
- Molecular Glycobiology, Research Team for Mechanism of Aging, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Itabashi-ku, Tokyo 173-0015, Japan.
| | - Tamao Endo
- Molecular Glycobiology, Research Team for Mechanism of Aging, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Itabashi-ku, Tokyo 173-0015, Japan.
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59
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Bhat HF, Mir SS, Dar KB, Bhat ZF, Shah RA, Ganai NA. ABC of multifaceted dystrophin glycoprotein complex (DGC). J Cell Physiol 2017; 233:5142-5159. [DOI: 10.1002/jcp.25982] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 05/01/2017] [Indexed: 01/16/2023]
Affiliation(s)
- Hina F. Bhat
- Division of BiotechnologySher‐e‐Kashmir University of Agricultural Sciences and Technology of Kashmir SKUAST‐KShuhama, SrinagarJammu and KashmirIndia
| | - Saima S. Mir
- Department of BiotechnologyUniversity of KashmirHazratbal, SrinagarJammu and KashmirIndia
| | - Khalid B. Dar
- Department of BiochemistryUniversity of KashmirHazratbal, SrinagarJammu and KashmirIndia
| | - Zuhaib F. Bhat
- Division of Livestock Products and TechnologySher‐e‐Kashmir University of Agricultural Sciences and Technology of Jammu (SKUAST‐J), R.S. PoraJammuJammu and KashmirIndia
| | - Riaz A. Shah
- Division of BiotechnologySher‐e‐Kashmir University of Agricultural Sciences and Technology of Kashmir SKUAST‐KShuhama, SrinagarJammu and KashmirIndia
| | - Nazir A. Ganai
- Division of BiotechnologySher‐e‐Kashmir University of Agricultural Sciences and Technology of Kashmir SKUAST‐KShuhama, SrinagarJammu and KashmirIndia
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60
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Larsen ISB, Narimatsu Y, Joshi HJ, Yang Z, Harrison OJ, Brasch J, Shapiro L, Honig B, Vakhrushev SY, Clausen H, Halim A. Mammalian O-mannosylation of cadherins and plexins is independent of protein O-mannosyltransferases 1 and 2. J Biol Chem 2017; 292:11586-11598. [PMID: 28512129 DOI: 10.1074/jbc.m117.794487] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Indexed: 11/06/2022] Open
Abstract
Protein O-mannosylation is found in yeast and metazoans, and a family of conserved orthologous protein O-mannosyltransferases is believed to initiate this important post-translational modification. We recently discovered that the cadherin superfamily carries O-linked mannose (O-Man) glycans at highly conserved residues in specific extracellular cadherin domains, and it was suggested that the function of E-cadherin was dependent on the O-Man glycans. Deficiencies in enzymes catalyzing O-Man biosynthesis, including the two human protein O-mannosyltransferases, POMT1 and POMT2, underlie a subgroup of congenital muscular dystrophies designated α-dystroglycanopathies, because deficient O-Man glycosylation of α-dystroglycan disrupts laminin interaction with α-dystroglycan and the extracellular matrix. To explore the functions of O-Man glycans on cadherins and protocadherins, we used a combinatorial gene-editing strategy in multiple cell lines to evaluate the role of the two POMTs initiating O-Man glycosylation and the major enzyme elongating O-Man glycans, the protein O-mannose β-1,2-N-acetylglucosaminyltransferase, POMGnT1. Surprisingly, O-mannosylation of cadherins and protocadherins does not require POMT1 and/or POMT2 in contrast to α-dystroglycan, and moreover, the O-Man glycans on cadherins are not elongated. Thus, the classical and evolutionarily conserved POMT O-mannosylation pathway is essentially dedicated to α-dystroglycan and a few other proteins, whereas a novel O-mannosylation process in mammalian cells is predicted to serve the large cadherin superfamily and other proteins.
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Affiliation(s)
- Ida Signe Bohse Larsen
- From the Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark, and
| | - Yoshiki Narimatsu
- From the Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark, and
| | - Hiren Jitendra Joshi
- From the Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark, and
| | - Zhang Yang
- From the Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark, and
| | | | - Julia Brasch
- the Department of Biochemistry and Molecular Biophysics
| | - Lawrence Shapiro
- the Department of Biochemistry and Molecular Biophysics.,Zuckerman Mind Brain Behavior Institute, Department of Systems Biology, and
| | - Barry Honig
- the Department of Biochemistry and Molecular Biophysics.,Zuckerman Mind Brain Behavior Institute, Department of Systems Biology, and.,Howard Hughes Medical Institute Columbia University, New York, New York 10032
| | - Sergey Y Vakhrushev
- From the Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark, and
| | - Henrik Clausen
- From the Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark, and
| | - Adnan Halim
- From the Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark, and
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61
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Reactivity of anti-HNK-1 antibodies to branched O- mannose glycans associated with demyelination. Biochem Biophys Res Commun 2017; 487:450-456. [DOI: 10.1016/j.bbrc.2017.04.085] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 04/16/2017] [Indexed: 11/21/2022]
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Booler HS, Pagalday-Vergara V, Williams JL, Hopkinson M, Brown SC. Evidence of early defects in Cajal-Retzius cell localization during brain development in a mouse model of dystroglycanopathy. Neuropathol Appl Neurobiol 2017; 43:330-345. [PMID: 28039900 DOI: 10.1111/nan.12376] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 08/10/2016] [Accepted: 12/31/2016] [Indexed: 01/21/2023]
Abstract
AIMS The secondary dystroglycanopathies represent a heterogeneous group of congenital muscular dystrophies characterized by the defective glycosylation of alpha dystroglycan. These disorders are associated with mutations in at least 17 genes, including Fukutin-related protein (FKRP). At the severe end of the clinical spectrum there is substantial brain involvement, and cobblestone lissencephaly is highly suggestive of these disorders. The precise pathogenesis of this phenotype has, however, remained unclear with most attention focused on the disruption to the radial glial scaffold. Here, we set out to investigate whether lesions are apparent prior to the differentiation of the radial glia. METHODS A detailed investigation of the structural brain defects from embryonic day 10.5 (E10.5) up until the time of birth (P0) was undertaken in the Fkrp-deficient mice (FKRPKD ). Reelin, and downstream PI3K/Akt signalling pathways were analysed using Western blot. RESULTS We show that early basement membrane defects and neuroglial ectopia precede radial glial cell differentiation. Furthermore, we identify mislocalization of Cajal-Retzius cells which nonetheless is not associated with any apparent disruption to the reelin, and downstream PI3K/Akt signalling pathways. CONCLUSIONS These observations identify Cajal-Retzius cell mislocalization as an early event during the development of cortical defects thereby identifying an earlier onset and more complex pathogenesis than originally reported for the secondary dystroglycanopathies. Overall this study provides new insight into central nervous system involvement in this group of diseases.
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Affiliation(s)
- H S Booler
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - V Pagalday-Vergara
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - J L Williams
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - M Hopkinson
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - S C Brown
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK
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63
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Hu P, Wu S, Yuan L, Lin Q, Zheng W, Xia H, Xu H, Guan L, Deng H. Compound heterozygous POMT1 mutations in a Chinese family with autosomal recessive muscular dystrophy-dystroglycanopathy C1. J Cell Mol Med 2017; 21:1388-1393. [PMID: 28157257 PMCID: PMC5487925 DOI: 10.1111/jcmm.13068] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 11/24/2016] [Indexed: 11/29/2022] Open
Abstract
Muscular dystrophy-dystroglycanopathy (MDDG) is a genetically and clinically heterogeneous group of muscular disorders, characterized by congenital muscular dystrophy or later-onset limb-girdle muscular dystrophy accompanied by brain and ocular abnormalities, resulting from aberrant alpha-dystroglycan glycosylation. Exome sequencing and Sanger sequencing were performed on a six-generation consanguineous Han Chinese family, members of which had autosomal recessive MDDG. Compound heterozygous mutations, c.1338+1G>A (p.H415Kfs*3) and c.1457G>C (p.W486S, rs746849558), in the protein O-mannosyltransferase 1 gene (POMT1), were identified as the genetic cause. Patients that exhibited milder MDDG manifested as later-onset progressive proximal pelvic, shoulder girdle and limb muscle weakness, joint contractures, mental retardation and elevated creatine kinase, without structural brain or ocular abnormalities, were further genetically diagnosed as MDDGC1. The POMT1 gene splice-site mutation (c.1338+1G>A) which leads to exon 13 skipping and results in a truncated protein may contribute to a severe phenotype, while the allelic missense mutation (p.W486S) may reduce MDDG severity. These findings may expand phenotype and mutation spectrum of the POMT1 gene. Clinical diagnosis supplemented with molecular screening may result in more accurate diagnoses of, prognoses for, and improved genetic counselling for this disease.
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Affiliation(s)
- Pengzhi Hu
- Center for Experimental Medicine and Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Song Wu
- Department of Orthopedics, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Lamei Yuan
- Center for Experimental Medicine and Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, China
| | | | - Wen Zheng
- Center for Experimental Medicine and Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Hong Xia
- Center for Experimental Medicine and Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Hongbo Xu
- Center for Experimental Medicine and Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, China
| | | | - Hao Deng
- Center for Experimental Medicine and Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, China
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64
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Keramaris E, Lu PJ, Tucker J, Lu QL. Expression of glycosylated α-dystroglycan in newborn skeletal and cardiac muscles of fukutin related protein (FKRP) mutant mice. Muscle Nerve 2016; 55:582-590. [DOI: 10.1002/mus.25378] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 08/05/2016] [Accepted: 08/10/2016] [Indexed: 12/27/2022]
Affiliation(s)
- Elizabeth Keramaris
- McColl-Lockwood Laboratory for Muscular Dystrophy Research; Cannon Research Center, Carolinas Medical Center; 1542 Garden Terrace Charlotte North Carolina 28203 USA
| | - Pei J. Lu
- McColl-Lockwood Laboratory for Muscular Dystrophy Research; Cannon Research Center, Carolinas Medical Center; 1542 Garden Terrace Charlotte North Carolina 28203 USA
| | - Jason Tucker
- McColl-Lockwood Laboratory for Muscular Dystrophy Research; Cannon Research Center, Carolinas Medical Center; 1542 Garden Terrace Charlotte North Carolina 28203 USA
| | - Qi L. Lu
- McColl-Lockwood Laboratory for Muscular Dystrophy Research; Cannon Research Center, Carolinas Medical Center; 1542 Garden Terrace Charlotte North Carolina 28203 USA
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Postnatal Gene Therapy Improves Spatial Learning Despite the Presence of Neuronal Ectopia in a Model of Neuronal Migration Disorder. Genes (Basel) 2016; 7:genes7120105. [PMID: 27916859 PMCID: PMC5192481 DOI: 10.3390/genes7120105] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 11/17/2016] [Accepted: 11/19/2016] [Indexed: 11/25/2022] Open
Abstract
Patients with type II lissencephaly, a neuronal migration disorder with ectopic neurons, suffer from severe mental retardation, including learning deficits. There is no effective therapy to prevent or correct the formation of neuronal ectopia, which is presumed to cause cognitive deficits. We hypothesized that learning deficits were not solely caused by neuronal ectopia and that postnatal gene therapy could improve learning without correcting the neuronal ectopia formed during fetal development. To test this hypothesis, we evaluated spatial learning of cerebral cortex-specific protein O-mannosyltransferase 2 (POMT2, an enzyme required for O-mannosyl glycosylation) knockout mice and compared to the knockout mice that were injected with an adeno-associated viral vector (AAV) encoding POMT2 into the postnatal brains with Barnes maze. The data showed that the knockout mice exhibited reduced glycosylation in the cerebral cortex, reduced dendritic spine density on CA1 neurons, and increased latency to the target hole in the Barnes maze, indicating learning deficits. Postnatal gene therapy restored functional glycosylation, rescued dendritic spine defects, and improved performance on the Barnes maze by the knockout mice even though neuronal ectopia was not corrected. These results indicate that postnatal gene therapy improves spatial learning despite the presence of neuronal ectopia.
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66
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Bouchet-Séraphin C, Chelbi-Viallon M, Vuillaumier-Barrot S, Seta N. [Genes of alpha-dystroglycanopathies in 2016]. Med Sci (Paris) 2016; 32 Hors série n°2:40-45. [PMID: 27869076 DOI: 10.1051/medsci/201632s210] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Céline Bouchet-Séraphin
- AP-HP, Hôpital Bichat Claude Bernard, Service de Biochimie, 75018 Paris, France - AP-HP, Hôpital Bichat Claude Bernard, Département de Génétique, 75018 Paris, France
| | | | - S Vuillaumier-Barrot
- AP-HP, Hôpital Bichat Claude Bernard, Service de Biochimie, 75018 Paris, France - AP-HP, Hôpital Bichat Claude Bernard, Département de Génétique, 75018 Paris, France - Inserm U733, Faculté Bichat, 75018 Paris, France
| | - N Seta
- AP-HP, Hôpital Bichat Claude Bernard, Service de Biochimie, 75018 Paris, France - Université Paris Descartes, 75006 Paris, France
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67
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Protein O-Mannosylation in the Murine Brain: Occurrence of Mono-O-Mannosyl Glycans and Identification of New Substrates. PLoS One 2016; 11:e0166119. [PMID: 27812179 PMCID: PMC5094735 DOI: 10.1371/journal.pone.0166119] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 10/24/2016] [Indexed: 12/25/2022] Open
Abstract
Protein O-mannosylation is a post-translational modification essential for correct development of mammals. In humans, deficient O-mannosylation results in severe congenital muscular dystrophies often associated with impaired brain and eye development. Although various O-mannosylated proteins have been identified in the recent years, the distribution of O-mannosyl glycans in the mammalian brain and target proteins are still not well defined. In the present study, rabbit monoclonal antibodies directed against the O-mannosylated peptide YAT(α1-Man)AV were generated. Detailed characterization of clone RKU-1-3-5 revealed that this monoclonal antibody recognizes O-linked mannose also in different peptide and protein contexts. Using this tool, we observed that mono-O-mannosyl glycans occur ubiquitously throughout the murine brain but are especially enriched at inhibitory GABAergic neurons and at the perineural nets. Using a mass spectrometry-based approach, we further identified glycoproteins from the murine brain that bear single O-mannose residues. Among the candidates identified are members of the cadherin and plexin superfamilies and the perineural net protein neurocan. In addition, we identified neurexin 3, a cell adhesion protein involved in synaptic plasticity, and inter-alpha-trypsin inhibitor 5, a protease inhibitor important in stabilizing the extracellular matrix, as new O-mannosylated glycoproteins.
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68
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Gautam J, Zhang X, Yao Y. The role of pericytic laminin in blood brain barrier integrity maintenance. Sci Rep 2016; 6:36450. [PMID: 27808256 PMCID: PMC5093438 DOI: 10.1038/srep36450] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 10/14/2016] [Indexed: 11/09/2022] Open
Abstract
Laminin, a major component of the basement membrane, plays an important role in blood brain barrier regulation. At the neurovascular unit, brain endothelial cells, astrocytes, and pericytes synthesize and deposit different laminin isoforms into the basement membrane. It has been shown that laminin α4 (endothelial laminin) regulates vascular integrity at embryonic/neonatal stage, while astrocytic laminin maintains vascular integrity in adulthood. Here, we investigate the function of pericyte-derived laminin in vascular integrity. Using a conditional knockout mouse line, we report that loss of pericytic laminin leads to hydrocephalus and BBB breakdown in a small percentage (10.7%) of the mutants. Interestingly, BBB disruption always goes hand-in-hand with hydrocephalus in these mutants, and neither symptom is observed in the rest 89.3% of the mutants. Further mechanistic studies show that reduced tight junction proteins, diminished AQP4 expression, and decreased pericyte coverage are responsible for the BBB disruption. Together, these data suggest that pericyte-derived laminin is involved in the maintenance of BBB integrity and regulation of ventricular size/development.
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Affiliation(s)
- Jyoti Gautam
- College of Pharmacy, University of Minnesota, 1110 Kirby Drive, Duluth, MN, 55812, USA
| | - Xuanming Zhang
- College of Pharmacy, University of Minnesota, 1110 Kirby Drive, Duluth, MN, 55812, USA
| | - Yao Yao
- College of Pharmacy, University of Minnesota, 1110 Kirby Drive, Duluth, MN, 55812, USA
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69
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Glycan Engineering for Cell and Developmental Biology. Cell Chem Biol 2016; 23:108-121. [PMID: 26933739 DOI: 10.1016/j.chembiol.2015.12.007] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 12/12/2015] [Accepted: 12/12/2015] [Indexed: 02/04/2023]
Abstract
Cell-surface glycans are a diverse class of macromolecules that participate in many key biological processes, including cell-cell communication, development, and disease progression. Thus, the ability to modulate the structures of glycans on cell surfaces provides a powerful means not only to understand fundamental processes but also to direct activity and elicit desired cellular responses. Here, we describe methods to sculpt glycans on cell surfaces and highlight recent successes in which artificially engineered glycans have been employed to control biological outcomes such as the immune response and stem cell fate.
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Astrea G, Battini R, Lenzi S, Frosini S, Bonetti S, Moretti E, Perazza S, Santorelli FM, Pecini C. Learning disabilities in neuromuscular disorders: a springboard for adult life. ACTA MYOLOGICA : MYOPATHIES AND CARDIOMYOPATHIES : OFFICIAL JOURNAL OF THE MEDITERRANEAN SOCIETY OF MYOLOGY 2016; 35:90-95. [PMID: 28344438 PMCID: PMC5343745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Although the presence of cognitive deficits in Duchenne muscular dystrophy or myotonic dystrophy DM1 is well established in view of brain-specific expression of affected muscle proteins, in other neuromuscular disorders, such as congenital myopathies and limb-girdle muscular dystrophies, cognitive profiles are poorly defined. Also, there are limited characterization of the cognitive profile of children with congenital muscular dystrophies, notwithstanding the presence of cerebral abnormality in some forms, and in spinal muscular atrophies, with the exception of distal spinal muscular atrophy (such as the DYN1CH1- associated form). Starting from the Duchenne muscular dystrophy, which may be considered a kind of paradigm for the co-occurrence of learning disabilities in the contest of a progressive muscular involvement, the findings of neuropsychological (or cognitive) dysfunctions in several forms of neuromuscular diseases will be examined and reviewed.
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Affiliation(s)
- Guja Astrea
- Departmet of Developmental Neuroscience, IRCCS Fondazione Stella Maris, Pisa;,Address for correspondence: Guja Astrea, IRCCS Stella Maris, via dei giacinti 2, 56128 Calambrone (PI). E-mail:
| | - Roberta Battini
- Departmet of Developmental Neuroscience, IRCCS Fondazione Stella Maris, Pisa
| | - Sara Lenzi
- Departmet of Developmental Neuroscience, IRCCS Fondazione Stella Maris, Pisa
| | - Silvia Frosini
- Departmet of Developmental Neuroscience, IRCCS Fondazione Stella Maris, Pisa
| | - Silvia Bonetti
- Departmet of Developmental Neuroscience, IRCCS Fondazione Stella Maris, Pisa
| | - Elena Moretti
- Departmet of Developmental Neuroscience, IRCCS Fondazione Stella Maris, Pisa
| | - Silvia Perazza
- Departmet of Developmental Neuroscience, IRCCS Fondazione Stella Maris, Pisa
| | | | - Chiara Pecini
- Departmet of Developmental Neuroscience, IRCCS Fondazione Stella Maris, Pisa
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Izquierdo-Lahuerta A, de Luis O, Gómez-Esquer F, Cruces J, Coloma A. Gallus gallus orthologous to human alpha-dystroglycanopathies candidate genes: Gene expression and characterization during chicken embryogenesis. Biochem Biophys Res Commun 2016; 478:1043-8. [PMID: 27553274 DOI: 10.1016/j.bbrc.2016.08.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 08/04/2016] [Indexed: 10/21/2022]
Abstract
Alpha-dystroglycanopathies are a heterogenic group of human rare diseases that have in common defects of α-dystroglycan O-glycosylation. These congenital disorders share common features as muscular dystrophy, malformations on central nervous system and more rarely altered ocular development, as well as mutations on a set of candidate genes involved on those syndromes. Severity of the syndromes is variable, appearing Walker-Warburg as the most severe where mutations at protein O-mannosyl transferases POMT1 and POMT2 genes are frequently described. When studying the lack of MmPomt1 in mouse embryonic development, as a murine model of Walker-Warburg syndrome, MmPomt1 null phenotype was lethal because Reitchert's membrane fails during embryonic development. Here, we report gene expression from Gallus gallus orthologous genes to human candidates on alpha-dystroglycanopathies POMT1, POMT2, POMGnT1, FKTN, FKRP and LARGE, making special emphasis in expression and localization of GgPomt1. Results obtained by quantitative RT-PCR, western-blot and immunochemistry revealed close gene expression patterns among human and chicken at key tissues affected during development when suffering an alpha-dystroglycanopathy, leading us to stand chicken as a useful animal model for molecular characterization of glycosyltransferases involved in the O-glycosylation of α-Dystroglycan and its role in embryonic development.
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Affiliation(s)
- Adriana Izquierdo-Lahuerta
- Departamento de Ciencias Básicas de la Salud, Área de Bioquímica, y Biología Molecular, Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, Avda. de Atenas s/n. 28922, Alcorcón, Madrid, Spain.
| | - Oscar de Luis
- Departamento de Ciencias Básicas de la Salud, Área de Bioquímica, y Biología Molecular, Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, Avda. de Atenas s/n. 28922, Alcorcón, Madrid, Spain
| | - Francisco Gómez-Esquer
- Departamento de Ciencias Básicas de la Salud, Area de Anatomía Humana y Embriología, Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, Avda. de Atenas s/n, 28922, Alcorcón, Madrid, Spain
| | - Jesús Cruces
- Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Madrid, C/ Arzobispo Morcillo 4, 28029, Madrid, Spain
| | - Antonio Coloma
- Departamento de Ciencias Básicas de la Salud, Área de Bioquímica, y Biología Molecular, Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, Avda. de Atenas s/n. 28922, Alcorcón, Madrid, Spain
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72
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Falsaperla R, Praticò AD, Ruggieri M, Parano E, Rizzo R, Corsello G, Vitaliti G, Pavone P. Congenital muscular dystrophy: from muscle to brain. Ital J Pediatr 2016; 42:78. [PMID: 27576556 PMCID: PMC5006267 DOI: 10.1186/s13052-016-0289-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 08/16/2016] [Indexed: 12/11/2022] Open
Abstract
Congenital muscular dystrophies (CMDs) are a wide group of muscular disorders that manifest with very early onset of muscular weakness, sometime associated to severe brain involvement.The histologic pattern of muscle anomalies is typical of dystrophic lesions but quite variable depending on the different stages and on the severity of the disorder.Recent classification of CMDs have been reported most of which based on the combination of clinical, biochemical, molecular and genetic findings, but genotype/phenotype correlation are in constant progression due to more diffuse utilization of the molecular analysis.In this article, the Authors report on CMDs belonging to the group of dystroglycanopathies and in particular on the most severe forms represented by the Fukuyama CMD, Muscle-Eye-Brain disease and Walker Walburg syndrome.Clinical diagnosis of infantile hypotonia is particularly difficult considering the different etiologic factors causing the lesions, the difficulty in localizing the involved CNS area (central vs. peripheral) and the limited role of the diagnostic procedures at this early age.The diagnostic evaluation is not easy mainly in differentiating the various types of CMDs, and represents a challenge for the neonatologists and pediatricians. Suggestions are reported on the way to reach a correct diagnosis with the appropriate use of the diagnostic means.
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Affiliation(s)
- Raffaele Falsaperla
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico-Vittorio Emanuele”, Catania, Italy
| | - Andrea D. Praticò
- Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Sciences, University of Catania, Catania, Italy
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Martino Ruggieri
- Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Sciences, University of Catania, Catania, Italy
| | - Enrico Parano
- National Research Council—Section of Catania, Catania, Italy
| | - Renata Rizzo
- Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Sciences, University of Catania, Catania, Italy
| | - Giovanni Corsello
- Department of Maternal and Child Health, University of Palermo, Palermo, Italy
| | - Giovanna Vitaliti
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico-Vittorio Emanuele”, Catania, Italy
| | - Piero Pavone
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico-Vittorio Emanuele”, Catania, Italy
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73
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Lucchese G, Kanduc D. Zika virus and autoimmunity: From microcephaly to Guillain-Barré syndrome, and beyond. Autoimmun Rev 2016; 15:801-8. [DOI: 10.1016/j.autrev.2016.03.020] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 03/18/2016] [Indexed: 10/22/2022]
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74
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Protein O-mannosylation in the early secretory pathway. Curr Opin Cell Biol 2016; 41:100-8. [DOI: 10.1016/j.ceb.2016.04.010] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 04/19/2016] [Accepted: 04/25/2016] [Indexed: 12/30/2022]
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75
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Transgenic Rescue of the LARGEmyd Mouse: A LARGE Therapeutic Window? PLoS One 2016; 11:e0159853. [PMID: 27467128 PMCID: PMC4965172 DOI: 10.1371/journal.pone.0159853] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 07/08/2016] [Indexed: 12/02/2022] Open
Abstract
LARGE is a glycosyltransferase involved in glycosylation of α-dystroglycan (α-DG). Absence of this protein in the LARGEmyd mouse results in α-DG hypoglycosylation, and is associated with central nervous system abnormalities and progressive muscular dystrophy. Up-regulation of LARGE has previously been proposed as a therapy for the secondary dystroglycanopathies: overexpression in cells compensates for defects in multiple dystroglycanopathy genes. Counterintuitively, LARGE overexpression in an FKRP-deficient mouse exacerbates pathology, suggesting that modulation of α-DG glycosylation requires further investigation. Here we demonstrate that transgenic expression of human LARGE (LARGE-LV5) in the LARGEmyd mouse restores α-DG glycosylation (with marked hyperglycosylation in muscle) and that this corrects both the muscle pathology and brain architecture. By quantitative analyses of LARGE transcripts we also here show that levels of transgenic and endogenous LARGE in the brains of transgenic animals are comparable, but that the transgene is markedly overexpressed in heart and particularly skeletal muscle (20–100 fold over endogenous). Our data suggest LARGE overexpression may only be deleterious under a forced regenerative context, such as that resulting from a reduction in FKRP: in the absence of such a defect we show that systemic expression of LARGE can indeed act therapeutically, and that even dramatic LARGE overexpression is well-tolerated in heart and skeletal muscle. Moreover, correction of LARGEmyd brain pathology with only moderate, near-physiological LARGE expression suggests a generous therapeutic window.
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76
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Inamori KI, Beedle AM, de Bernabé DBV, Wright ME, Campbell KP. LARGE2-dependent glycosylation confers laminin-binding ability on proteoglycans. Glycobiology 2016; 26:1284-1296. [PMID: 27496765 PMCID: PMC5137251 DOI: 10.1093/glycob/cww075] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 07/08/2016] [Accepted: 07/18/2016] [Indexed: 01/16/2023] Open
Abstract
Both LARGE1 (formerly LARGE) and its paralog LARGE2 are bifunctional glycosyltransferases with xylosy- and glucuronyltransferase activities, and are capable of synthesizing polymers composed of a repeating disaccharide [-3Xylα1,3GlcAβ1-]. Post-translational modification of the O-mannosyl glycan of α-dystroglycan (α-DG) with the polysaccharide is essential for it to act as a receptor for ligands in the extracellular matrix (ECM), and both LARGE paralogs contribute to the modification in vivo. LARGE1 and LARGE2 have different tissue distribution profiles and enzymatic properties; however, the functional difference of the homologs remains to be determined, and α-DG is the only known substrate for the modification by LARGE1 or LARGE2. Here we show that LARGE2 can modify proteoglycans (PGs) with the laminin-binding glycan. We found that overexpression of LARGE2, but not LARGE1, mediates the functional modification on the surface of DG-/-, Pomt1-/- and Fktn-/- embryonic stem cells. We identified a heparan sulfate-PG glypican-4 as a substrate for the LARGE2-dependent modification by affinity purification and subsequent mass spectrometric analysis. Furthermore, we showed that LARGE2 could modify several additional PGs with the laminin-binding glycan, most likely within the glycosaminoglycan (GAG)-protein linkage region. Our results indicate that LARGE2 can modify PGs with the GAG-like polysaccharide composed of xylose and glucuronic acid to confer laminin binding. Thus, LARGE2 may play a differential role in stabilizing the basement membrane and modifying its functions by augmenting the interactions between laminin globular domain-containing ECM proteins and PGs.
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Affiliation(s)
- Kei-Ichiro Inamori
- Department of Molecular Physiology and Biophysics, Howard Hughes Medical Institute, and.,Department of Neurology, Howard Hughes Medical Institute, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242-1101, USA.,Division of Glycopathology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Miyagi 981-8558, Japan
| | - Aaron M Beedle
- Department of Molecular Physiology and Biophysics, Howard Hughes Medical Institute, and.,Department of Neurology, Howard Hughes Medical Institute, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242-1101, USA.,Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA 30602
| | - Daniel Beltrán-Valero de Bernabé
- Department of Molecular Physiology and Biophysics, Howard Hughes Medical Institute, and.,Department of Neurology, Howard Hughes Medical Institute, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242-1101, USA
| | - Michael E Wright
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA 30602.,Department of Molecular Physiology and Biophysics, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242-1101, USA
| | - Kevin P Campbell
- Department of Molecular Physiology and Biophysics, Howard Hughes Medical Institute, and .,Department of Neurology, Howard Hughes Medical Institute, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242-1101, USA
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77
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Bausewein D, Engel J, Jank T, Schoedl M, Strahl S. Functional Similarities between the Protein O-Mannosyltransferases Pmt4 from Bakers' Yeast and Human POMT1. J Biol Chem 2016; 291:18006-15. [PMID: 27358400 PMCID: PMC5016187 DOI: 10.1074/jbc.m116.739128] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Indexed: 11/21/2022] Open
Abstract
Protein O-mannosylation is an essential post-translational modification. It is initiated in the endoplasmic reticulum by a family of protein O-mannosyltransferases that are conserved from yeast (PMTs) to human (POMTs). The degree of functional conservation between yeast and human protein O-mannosyltransferases is uncharacterized. In bakers' yeast, the main in vivo activities are due to heteromeric Pmt1-Pmt2 and homomeric Pmt4 complexes. Here we describe an enzymatic assay that allowed us to monitor Pmt4 activity in vitro. We demonstrate that detergent requirements and acceptor substrates of yeast Pmt4 are different from Pmt1-Pmt2, but resemble that of human POMTs. Furthermore, we mimicked two POMT1 amino acid exchanges (G76R and V428D) that result in severe congenital muscular dystrophies in humans, in yeast Pmt4 (I112R and I435D). In vivo and in vitro analyses showed that general features such as protein stability of the Pmt4 variants were not significantly affected, however, the mutants proved largely enzymatically inactive. Our results demonstrate functional and biochemical similarities between POMT1 and its orthologue from bakers' yeast Pmt4.
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Affiliation(s)
- Daniela Bausewein
- From the Centre for Organismal Studies, Cell Chemistry, Heidelberg University, 69120 Heidelberg, Germany
| | - Jakob Engel
- From the Centre for Organismal Studies, Cell Chemistry, Heidelberg University, 69120 Heidelberg, Germany
| | - Thomas Jank
- From the Centre for Organismal Studies, Cell Chemistry, Heidelberg University, 69120 Heidelberg, Germany
| | - Maria Schoedl
- From the Centre for Organismal Studies, Cell Chemistry, Heidelberg University, 69120 Heidelberg, Germany
| | - Sabine Strahl
- From the Centre for Organismal Studies, Cell Chemistry, Heidelberg University, 69120 Heidelberg, Germany
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78
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Expression pattern in retinal photoreceptors of POMGnT1, a protein involved in muscle-eye-brain disease. Mol Vis 2016; 22:658-73. [PMID: 27375352 PMCID: PMC4911909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Accepted: 06/14/2016] [Indexed: 11/01/2022] Open
Abstract
PURPOSE The POMGNT1 gene, encoding protein O-linked-mannose β-1,2-N-acetylglucosaminyltransferase 1, is associated with muscle-eye-brain disease (MEB) and other dystroglycanopathies. This gene's lack of function or expression causes hypoglycosylation of α-dystroglycan (α-DG) in the muscle and the central nervous system, including the brain and the retina. The ocular symptoms of patients with MEB include retinal degeneration and detachment, glaucoma, and abnormal electroretinogram. Nevertheless, the POMGnT1 expression pattern in the healthy mammalian retina has not yet been investigated. In this work, we address the expression of the POMGNT1 gene in the healthy retina of a variety of mammals and characterize the distribution pattern of this gene in the adult mouse retina and the 661W photoreceptor cell line. METHODS Using reverse transcription (RT)-PCR and immunoblotting, we studied POMGNT1 expression at the mRNA and protein levels in various mammalian species, from rodents to humans. Immunofluorescence confocal microscopy analyses were performed to characterize the distribution profile of its protein product in mouse retinal sections and in 661W cultured cells. The intranuclear distribution of POMT1 and POMT2, the two enzymes preceding POMGnT1 in the α-DG O-mannosyl glycosylation pathway, was also analyzed. RESULTS POMGNT1 mRNA and its encoded protein were expressed in the neural retina of all mammals studied. POMGnT1 was located in the cytoplasmic fraction in the mouse retina and concentrated in the myoid portion of the photoreceptor inner segments, where the protein colocalized with GM130, a Golgi complex marker. The presence of POMGnT1 in the Golgi complex was also evident in 661W cells. However, and in contrast to retinal tissue, POMGnT1 additionally accumulated in the nucleus of the 661W photoreceptors. Colocalization was found within this organelle between POMGnT1 and POMT1/2, the latter associated with euchromatic regions of the nucleus. CONCLUSIONS Our results indicate that POMGnT1 participates not only in the synthesis of O-mannosyl glycans added to α-DG in the Golgi complex but also in the glycosylation of other yet-to-be-identified proteins in the nucleus of mouse photoreceptors.
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Glucocorticoid Steroid and Alendronate Treatment Alleviates Dystrophic Phenotype with Enhanced Functional Glycosylation of α-Dystroglycan in Mouse Model of Limb-Girdle Muscular Dystrophy with FKRPP448L Mutation. THE AMERICAN JOURNAL OF PATHOLOGY 2016; 186:1635-48. [DOI: 10.1016/j.ajpath.2016.02.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 02/02/2016] [Accepted: 02/19/2016] [Indexed: 12/13/2022]
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80
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Analysis of phenotype, enzyme activity and genotype of Chinese patients with POMT1 mutation. J Hum Genet 2016; 61:753-9. [PMID: 27193224 DOI: 10.1038/jhg.2016.42] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Revised: 03/04/2016] [Accepted: 03/30/2016] [Indexed: 01/20/2023]
Abstract
Protein O-mannosyltransferase 1 (POMT1) is a glycosyltransferase involved in α-dystroglycan glycosylation. POMT1 mutations cause a wide spectrum of clinical conditions from Walker-Warburg syndrome (WWS), which involves muscle, eye and brain abnormalities, to mild forms of limb-girdle muscular dystrophy with mental retardation. We aimed to elucidate the impact of different POMT1 mutations on the clinical phenotype. We report five Chinese patients with POMT1 mutations: one had a typical clinical manifestation of WWS, and the other four were diagnosed with congenital muscular dystrophy with mental retardation of varying severity. We analyzed the influence of the POMT1 mutations on POMT activity by assaying the patients' muscles and cultured skin fibroblasts. We demonstrated different levels of decreased POMT activity that correlated highly with decreased α-dystroglycan glycosylation. Our results suggest that POMT activity is inversely proportional to clinical severity, and demonstrate that skin fibroblasts can be used for differential diagnosis of patients with α-dystroglycanopathies. We have provided clinical, histological, enzymatic and genetic evidence of POMT1 involvement in five unrelated Chinese patients.
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81
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Gerin I, Ury B, Breloy I, Bouchet-Seraphin C, Bolsée J, Halbout M, Graff J, Vertommen D, Muccioli GG, Seta N, Cuisset JM, Dabaj I, Quijano-Roy S, Grahn A, Van Schaftingen E, Bommer GT. ISPD produces CDP-ribitol used by FKTN and FKRP to transfer ribitol phosphate onto α-dystroglycan. Nat Commun 2016; 7:11534. [PMID: 27194101 PMCID: PMC4873967 DOI: 10.1038/ncomms11534] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 04/06/2016] [Indexed: 01/27/2023] Open
Abstract
Mutations in genes required for the glycosylation of α-dystroglycan lead to muscle and brain diseases known as dystroglycanopathies. However, the precise structure and biogenesis of the assembled glycan are not completely understood. Here we report that three enzymes mutated in dystroglycanopathies can collaborate to attach ribitol phosphate onto α-dystroglycan. Specifically, we demonstrate that isoprenoid synthase domain-containing protein (ISPD) synthesizes CDP-ribitol, present in muscle, and that both recombinant fukutin (FKTN) and fukutin-related protein (FKRP) can transfer a ribitol phosphate group from CDP-ribitol to α-dystroglycan. We also show that ISPD and FKTN are essential for the incorporation of ribitol into α-dystroglycan in HEK293 cells. Glycosylation of α-dystroglycan in fibroblasts from patients with hypomorphic ISPD mutations is reduced. We observe that in some cases glycosylation can be partially restored by addition of ribitol to the culture medium, suggesting that dietary supplementation with ribitol should be evaluated as a therapy for patients with ISPD mutations.
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Affiliation(s)
- Isabelle Gerin
- WELBIO and de Duve Institute, Biological Chemistry, Université Catholique de Louvain, B-1200 Brussels, Belgium
| | - Benoît Ury
- WELBIO and de Duve Institute, Biological Chemistry, Université Catholique de Louvain, B-1200 Brussels, Belgium
| | - Isabelle Breloy
- Institute for Biochemistry II, Medical Faculty, University of Cologne, D-50931 Cologne, Germany
| | - Céline Bouchet-Seraphin
- AP-HP, Hôpital Bichat-Claude Bernard, Laboratoire de Biochimie Métabolique et Cellulaire, F-75018 Paris, France
| | - Jennifer Bolsée
- WELBIO and de Duve Institute, Biological Chemistry, Université Catholique de Louvain, B-1200 Brussels, Belgium
| | - Mathias Halbout
- WELBIO and de Duve Institute, Biological Chemistry, Université Catholique de Louvain, B-1200 Brussels, Belgium
| | - Julie Graff
- WELBIO and de Duve Institute, Biological Chemistry, Université Catholique de Louvain, B-1200 Brussels, Belgium
| | - Didier Vertommen
- WELBIO and de Duve Institute, Biological Chemistry, Université Catholique de Louvain, B-1200 Brussels, Belgium
| | - Giulio G Muccioli
- Louvain Drug Research Institute, Université Catholique de Louvain, B-1200 Brussels, Belgium
| | - Nathalie Seta
- AP-HP, Hôpital Bichat-Claude Bernard, Laboratoire de Biochimie Métabolique et Cellulaire, F-75018 Paris, France
| | - Jean-Marie Cuisset
- Hôpital Roger-Salengro, Service de neuropédiatrie, Centre de Référence des Maladies Neuromusculaires, CHRU, F-59000 Lille, France
| | - Ivana Dabaj
- AP-HP, Hôpital R Poincaré, Service de pédiatrie, F-92380 Garches, France
| | - Susana Quijano-Roy
- AP-HP, Hôpital R Poincaré, Service de pédiatrie, F-92380 Garches, France.,Centre de Référence des Maladies Neuromusculaires, F-92380 Garches, France.,Université de Versailles-St Quentin, U1179 UVSQ - INSERM, F-78180 Montigny, France
| | - Ammi Grahn
- WELBIO and de Duve Institute, Biological Chemistry, Université Catholique de Louvain, B-1200 Brussels, Belgium
| | - Emile Van Schaftingen
- WELBIO and de Duve Institute, Biological Chemistry, Université Catholique de Louvain, B-1200 Brussels, Belgium
| | - Guido T Bommer
- WELBIO and de Duve Institute, Biological Chemistry, Université Catholique de Louvain, B-1200 Brussels, Belgium
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82
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Fernández V, Llinares-Benadero C, Borrell V. Cerebral cortex expansion and folding: what have we learned? EMBO J 2016; 35:1021-44. [PMID: 27056680 PMCID: PMC4868950 DOI: 10.15252/embj.201593701] [Citation(s) in RCA: 222] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 02/23/2016] [Accepted: 03/17/2016] [Indexed: 01/22/2023] Open
Abstract
One of the most prominent features of the human brain is the fabulous size of the cerebral cortex and its intricate folding. Cortical folding takes place during embryonic development and is important to optimize the functional organization and wiring of the brain, as well as to allow fitting a large cortex in a limited cranial volume. Pathological alterations in size or folding of the human cortex lead to severe intellectual disability and intractable epilepsy. Hence, cortical expansion and folding are viewed as key processes in mammalian brain development and evolution, ultimately leading to increased intellectual performance and, eventually, to the emergence of human cognition. Here, we provide an overview and discuss some of the most significant advances in our understanding of cortical expansion and folding over the last decades. These include discoveries in multiple and diverse disciplines, from cellular and molecular mechanisms regulating cortical development and neurogenesis, genetic mechanisms defining the patterns of cortical folds, the biomechanics of cortical growth and buckling, lessons from human disease, and how genetic evolution steered cortical size and folding during mammalian evolution.
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Affiliation(s)
- Virginia Fernández
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas & Universidad Miguel Hernández, Sant Joan d'Alacant, Spain
| | - Cristina Llinares-Benadero
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas & Universidad Miguel Hernández, Sant Joan d'Alacant, Spain
| | - Víctor Borrell
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas & Universidad Miguel Hernández, Sant Joan d'Alacant, Spain
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83
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Abstract
Studies of syndromic hydrocephalus have led to the identification of >100 causative genes. Even though this work has illuminated numerous pathways associated with hydrocephalus, it has also highlighted the fact that the genetics underlying this phenotype are more complex than anticipated originally. Mendelian forms of hydrocephalus account for a small fraction of the genetic burden, with clear evidence of background-dependent effects of alleles on penetrance and expressivity of driver mutations in key developmental and homeostatic pathways. Here, we synthesize the currently implicated genes and inheritance paradigms underlying hydrocephalus, grouping causal loci into functional modules that affect discrete, albeit partially overlapping, cellular processes. These in turn have the potential to both inform pathomechanism and assist in the rational molecular classification of a clinically heterogeneous phenotype. Finally, we discuss conceptual methods that can lead to enhanced gene identification and dissection of disease basis, knowledge that will potentially form a foundation for the design of future therapeutics.
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Affiliation(s)
- Maria Kousi
- Center for Human Disease Modeling, Duke University School of Medicine, Durham, North Carolina 27701;
| | - Nicholas Katsanis
- Center for Human Disease Modeling, Duke University School of Medicine, Durham, North Carolina 27701;
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84
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Praissman JL, Willer T, Sheikh MO, Toi A, Chitayat D, Lin YY, Lee H, Stalnaker SH, Wang S, Prabhakar PK, Nelson SF, Stemple DL, Moore SA, Moremen KW, Campbell KP, Wells L. The functional O-mannose glycan on α-dystroglycan contains a phospho-ribitol primed for matriglycan addition. eLife 2016; 5. [PMID: 27130732 PMCID: PMC4924997 DOI: 10.7554/elife.14473] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 04/28/2016] [Indexed: 12/24/2022] Open
Abstract
Multiple glycosyltransferases are essential for the proper modification of alpha-dystroglycan, as mutations in the encoding genes cause congenital/limb-girdle muscular dystrophies. Here we elucidate further the structure of an O-mannose-initiated glycan on alpha-dystroglycan that is required to generate its extracellular matrix-binding polysaccharide. This functional glycan contains a novel ribitol structure that links a phosphotrisaccharide to xylose. ISPD is a CDP-ribitol (ribose) pyrophosphorylase that generates the reduced sugar nucleotide for the insertion of ribitol in a phosphodiester linkage to the glycoprotein. TMEM5 is a UDP-xylosyl transferase that elaborates the structure. We demonstrate in a zebrafish model as well as in a human patient that defects in TMEM5 result in muscular dystrophy in combination with abnormal brain development. Thus, we propose a novel structure—a ribitol in a phosphodiester linkage—for the moiety on which TMEM5, B4GAT1, and LARGE act to generate the functional receptor for ECM proteins having LG domains. DOI:http://dx.doi.org/10.7554/eLife.14473.001
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Affiliation(s)
- Jeremy L Praissman
- Complex Carbohydrate Research Center, University of Georgia, Athens, United States
| | - Tobias Willer
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, United States.,Howard Hughes Medical Institute, University of Iowa, Iowa City, United States.,Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, United States.,Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, United States
| | - M Osman Sheikh
- Complex Carbohydrate Research Center, University of Georgia, Athens, United States
| | - Ants Toi
- Department of Medical Imaging, Mount Sinai Hospital, Toronto, Canada
| | - David Chitayat
- Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, University of Toronto, Toronto, Canada.,The Prenatal Diagnosis and Medical Genetics Program, Mount Sinai Hospital, Toronto, Canada.,Department of Obstetrics and Gynecology, University of Toronto, Toronto, Canada
| | - Yung-Yao Lin
- Blizard Institute, London, United Kingdom.,Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom.,Wellcome Trust Genome Campus, Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Hane Lee
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, United States.,David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States.,Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, United States
| | | | - Shuo Wang
- Complex Carbohydrate Research Center, University of Georgia, Athens, United States
| | | | - Stanley F Nelson
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, United States.,David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States.,Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Derek L Stemple
- Wellcome Trust Genome Campus, Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Steven A Moore
- Department of Pathology, Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Kelley W Moremen
- Complex Carbohydrate Research Center, University of Georgia, Athens, United States.,Department of Biochemistry and Molecular Biology, University of Georgia, Athens, United States
| | - Kevin P Campbell
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, United States.,Howard Hughes Medical Institute, University of Iowa, Iowa City, United States.,Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, United States.,Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Lance Wells
- Complex Carbohydrate Research Center, University of Georgia, Athens, United States.,Department of Biochemistry and Molecular Biology, University of Georgia, Athens, United States
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85
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A New Mouse Model of Limb-Girdle Muscular Dystrophy Type 2I Homozygous for the Common L276I Mutation Mimicking the Mild Phenotype in Humans. J Neuropathol Exp Neurol 2016; 74:1137-46. [PMID: 26574668 DOI: 10.1097/nen.0000000000000260] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Limb-girdle muscular dystrophy type 2I (LGMD2I) is caused by mutations in the Fukutin-related protein (FKRP) gene, leading to inadequate glycosylation of α-dystroglycan, an important protein linking the extracellular matrix to the cytoskeleton. We created a mouse model of the common FKRP L276I mutation and a hemizygous FKRP L276I knockout model. We studied histopathology and protein expression in the models at different ages and found that homozygous FKRP L276I mice developed a mild progressive myopathy with increased muscle regeneration and fibrosis starting from 1 year of age. This was likely caused by progressive loss of α-dystroglycan-specific glycosylation, which was decreased by 78% at 20 months. The homozygous FKRP knockout was embryonic lethal, but the hemizygous L276I model resembled the homozygous FKRP L276I model at comparable ages. These models emphasize the importance of FKRP in maintaining proper glycosylation of α-dystroglycan. The mild progression in the homozygous FKRP L276I model resembles that in patients with LGMD2I who are homozygous for the L276I mutation. This animal model could, therefore, be relevant for understanding the pathophysiology of and developing a treatment strategy for the human disorder.
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86
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Kim J, Hopkinson M, Kavishwar M, Fernandez-Fuente M, Brown SC. Prenatal muscle development in a mouse model for the secondary dystroglycanopathies. Skelet Muscle 2016; 6:3. [PMID: 26900448 PMCID: PMC4759920 DOI: 10.1186/s13395-016-0073-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 01/05/2016] [Indexed: 12/17/2022] Open
Abstract
Background The defective glycosylation of α-dystroglycan is associated with a group of muscular dystrophies that are collectively referred to as the secondary dystroglycanopathies. Mutations in the gene encoding fukutin-related protein (FKRP) are one of the most common causes of secondary dystroglycanopathy in the UK and are associated with a wide spectrum of disease. Whilst central nervous system involvement has a prenatal onset, no studies have addressed prenatal muscle development in any of the mouse models for this group of diseases. In view of the pivotal role of α-dystroglycan in early basement membrane formation, we sought to determine if the muscle formation was altered in a mouse model of FKRP-related dystrophy. Results Mice with a knock-down in FKRP (FKRPKD) showed a marked reduction in α-dystroglycan glycosylation and reduction in laminin binding by embryonic day 15.5 (E15.5), relative to wild type controls. In addition, the total number of Pax7+ progenitor cells in the FKRPKD tibialis anterior at E15.5 was significantly reduced, and myotube cluster/myofibre size showed a significant reduction in size. Moreover, myoblasts isolated from the limb muscle of these mice at E15.5 showed a marked reduction in their ability to form myotubes in vitro. Conclusions These data identify an early reduction of laminin α2, reduction of myogenicity and depletion of Pax7+ progenitor cells which would be expected to compromise subsequent postnatal muscle growth and its ability to regenerate postnatally. These findings are of significance to the development of future therapies in this group of devastating conditions.
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Affiliation(s)
- Jihee Kim
- Department of Comparative Biomedical Sciences, Royal Veterinary College, University of London, London, UK
| | - Mark Hopkinson
- Department of Comparative Biomedical Sciences, Royal Veterinary College, University of London, London, UK
| | - Manoli Kavishwar
- Department of Comparative Biomedical Sciences, Royal Veterinary College, University of London, London, UK
| | - Marta Fernandez-Fuente
- Department of Comparative Biomedical Sciences, Royal Veterinary College, University of London, London, UK
| | - Susan Carol Brown
- Department of Comparative Biomedical Sciences, Royal Veterinary College, University of London, London, UK
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87
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Saunier M, Bönnemann CG, Durbeej M, Allamand V. 212th ENMC International Workshop: Animal models of congenital muscular dystrophies, Naarden, The Netherlands, 29-31 May 2015. Neuromuscul Disord 2016; 26:252-9. [PMID: 26948708 DOI: 10.1016/j.nmd.2016.02.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 02/08/2016] [Accepted: 02/09/2016] [Indexed: 12/18/2022]
Affiliation(s)
- M Saunier
- UPMC Univ Paris 06, Inserm UMRS974, CNRS FRE3617, Center for Research in Myology, Institut de Myologie, GH Pitié-Salpêtrière, Sorbonne Universités, F-75013 Paris, France
| | - C G Bönnemann
- National Institutes of Health, Neuromuscular and Neurogenetic Disorders of Childhood Section, Bethesda, MD, USA
| | - M Durbeej
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - V Allamand
- UPMC Univ Paris 06, Inserm UMRS974, CNRS FRE3617, Center for Research in Myology, Institut de Myologie, GH Pitié-Salpêtrière, Sorbonne Universités, F-75013 Paris, France.
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88
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Neubert P, Halim A, Zauser M, Essig A, Joshi HJ, Zatorska E, Larsen ISB, Loibl M, Castells-Ballester J, Aebi M, Clausen H, Strahl S. Mapping the O-Mannose Glycoproteome in Saccharomyces cerevisiae. Mol Cell Proteomics 2016; 15:1323-37. [PMID: 26764011 PMCID: PMC4824858 DOI: 10.1074/mcp.m115.057505] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Indexed: 11/17/2022] Open
Abstract
O-Mannosylation is a vital protein modification conserved from fungi to humans. Yeast is a perfect model to study this post-translational modification, because in contrast to mammals O-mannosylation is the only type of O-glycosylation. In an essential step toward the full understanding of protein O-mannosylation we mapped the O-mannose glycoproteome in baker's yeast. Taking advantage of an O-glycan elongation deficient yeast strain to simplify sample complexity, we identified over 500 O-glycoproteins from all subcellular compartments for which over 2300 O-mannosylation sites were mapped by electron-transfer dissociation (ETD)-based MS/MS. In this study, we focus on the 293 O-glycoproteins (over 1900 glycosylation sites identified by ETD-MS/MS) that enter the secretory pathway and are targets of ER-localized protein O-mannosyltransferases. We find that O-mannosylation is not only a prominent modification of cell wall and plasma membrane proteins, but also of a large number of proteins from the secretory pathway with crucial functions in protein glycosylation, folding, quality control, and trafficking. The analysis of glycosylation sites revealed that O-mannosylation is favored in unstructured regions and β-strands. Furthermore, O-mannosylation is impeded in the proximity of N-glycosylation sites suggesting the interplay of these types of post-translational modifications. The detailed knowledge of the target proteins and their O-mannosylation sites opens for discovery of new roles of this essential modification in eukaryotes, and for a first glance on the evolution of different types of O-glycosylation from yeast to mammals.
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Affiliation(s)
- Patrick Neubert
- From the ‡Centre for Organismal Studies (COS), Department of Cell Chemistry, Heidelberg University, Im Neuenheimer Feld 360, D-69120 Heidelberg, Germany
| | - Adnan Halim
- §Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
| | - Martin Zauser
- From the ‡Centre for Organismal Studies (COS), Department of Cell Chemistry, Heidelberg University, Im Neuenheimer Feld 360, D-69120 Heidelberg, Germany
| | - Andreas Essig
- ¶Institute of Microbiology, Department of Biology, Swiss Federal Institute of Technology, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Hiren J Joshi
- §Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
| | - Ewa Zatorska
- From the ‡Centre for Organismal Studies (COS), Department of Cell Chemistry, Heidelberg University, Im Neuenheimer Feld 360, D-69120 Heidelberg, Germany
| | - Ida Signe Bohse Larsen
- §Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
| | - Martin Loibl
- From the ‡Centre for Organismal Studies (COS), Department of Cell Chemistry, Heidelberg University, Im Neuenheimer Feld 360, D-69120 Heidelberg, Germany
| | - Joan Castells-Ballester
- From the ‡Centre for Organismal Studies (COS), Department of Cell Chemistry, Heidelberg University, Im Neuenheimer Feld 360, D-69120 Heidelberg, Germany
| | - Markus Aebi
- ¶Institute of Microbiology, Department of Biology, Swiss Federal Institute of Technology, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Henrik Clausen
- §Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
| | - Sabine Strahl
- From the ‡Centre for Organismal Studies (COS), Department of Cell Chemistry, Heidelberg University, Im Neuenheimer Feld 360, D-69120 Heidelberg, Germany;
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89
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Ragni E, Lommel M, Moro M, Crosti M, Lavazza C, Parazzi V, Saredi S, Strahl S, Lazzari L. Protein O-mannosylation is crucial for human mesencyhmal stem cells fate. Cell Mol Life Sci 2016; 73:445-58. [PMID: 26245304 PMCID: PMC11108538 DOI: 10.1007/s00018-015-2007-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 07/27/2015] [Accepted: 07/29/2015] [Indexed: 10/23/2022]
Abstract
Human mesenchymal stem cells (MSC) are promising cell types in the field of regenerative medicine. Although many pathways have been dissected in the effort to better understand and characterize MSC potential, the impact of protein N- or O-glycosylation has been neglected. Deficient protein O-mannosylation is a pathomechanism underlying severe congenital muscular dystrophies (CMD) that start to develop at the embryonic developmental stage and progress in the adult, often in tissues where MSC exert their function. Here we show that O-mannosylation genes, many of which are putative or verified glycosyltransferases (GTs), are expressed in a similar pattern in MSC from adipose tissue, bone marrow, and umbilical cord blood and that their expression levels are retained constant during mesengenic differentiation. Inhibition of the first players of the enzymatic cascade, POMT1/2, resulted in complete abolishment of chondrogenesis and alterations of adipogenic and osteogenic potential together with a lethal effect during myogenic induction. Since to date, no therapy for CMD is available, we explored the possibility of using MSC extracellular vesicles (EVs) as molecular source of functional GTs mRNA. All MSC secrete POMT1 mRNA-containing EVs that are able to efficiently fuse with myoblasts which are among the most affected cells by CMD. Intriguingly, in a pomt1 patient myoblast line EVs were able to partially revert O-mannosylation deficiency and contribute to a morphology recovery. Altogether, these results emphasize the crucial role of protein O-mannosylation in stem cell fate and properties and open the possibility of using MSC vesicles as a novel therapeutic approach to CMD.
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Affiliation(s)
- E Ragni
- Cell Factory, Unit of Cell Therapy and Cryobiology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - M Lommel
- Centre for Organismal Studies, Cell Chemistry and Center for Molecular Biology, University of Heidelberg, 69120, Heidelberg, Germany
| | - M Moro
- Istituto Nazionale Genetica Molecolare "Romeo ed Enrica Invernizzi" (INGM), Milan, Italy
| | - M Crosti
- Istituto Nazionale Genetica Molecolare "Romeo ed Enrica Invernizzi" (INGM), Milan, Italy
| | - C Lavazza
- Cell Factory, Unit of Cell Therapy and Cryobiology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - V Parazzi
- Cell Factory, Unit of Cell Therapy and Cryobiology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - S Saredi
- Division of Neuromuscular Diseases and Neuroimmunology, Fondazione IRCCS Istituto Neurologico C. Besta, Milan, Italy
| | - S Strahl
- Centre for Organismal Studies, Cell Chemistry and Center for Molecular Biology, University of Heidelberg, 69120, Heidelberg, Germany
| | - L Lazzari
- Cell Factory, Unit of Cell Therapy and Cryobiology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
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90
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Krag TO, Vissing J. A New Mouse Model of Limb-Girdle Muscular Dystrophy Type 2I Homozygous for the Common L276I Mutation Mimicking the Mild Phenotype in Humans. J Neuropathol Exp Neurol 2015. [DOI: 10.1093/jnen/74.12.1137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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91
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Small molecules enhance functional O-mannosylation of Alpha-dystroglycan. Bioorg Med Chem 2015; 23:7661-70. [PMID: 26652968 DOI: 10.1016/j.bmc.2015.11.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 10/30/2015] [Accepted: 11/12/2015] [Indexed: 12/23/2022]
Abstract
Alpha-dystroglycan (α-DG), a highly glycosylated receptor for extracellular matrix proteins, plays a critical role in many biological processes. Hypoglycosylation of α-DG results in various types of muscular dystrophies and is also highly associated with progression of majority of cancers. Currently, there are no effective treatments for those devastating diseases. Enhancing functional O-mannosyl glycans (FOG) of α-DG on the cell surfaces is a potential approach to address this unmet challenge. Based on the hypothesis that the cells can up-regulate FOG of α-DG in response to certain chemical stimuli, we developed a cell-based high-throughput screening (HTS) platform for searching chemical enhancers of FOG of α-DG from a large chemical library with 364,168 compounds. Sequential validation of the hits from a primary screening campaign and chemical works led to identification of a cluster of compounds that positively modulate FOG of α-DG on various cell surfaces including patient-derived myoblasts. These compounds enhance FOG of α-DG by almost ten folds, which provide us powerful tools for O-mannosylation studies and potential starting points for the development of drug to treat dystroglycanopathy.
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92
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Booler HS, Williams JL, Hopkinson M, Brown SC. Degree of Cajal-Retzius Cell Mislocalization Correlates with the Severity of Structural Brain Defects in Mouse Models of Dystroglycanopathy. Brain Pathol 2015; 26:465-78. [PMID: 26306834 DOI: 10.1111/bpa.12306] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 08/23/2015] [Indexed: 12/19/2022] Open
Abstract
The secondary dystroglycanopathies are characterized by the hypoglycosylation of alpha dystroglycan, and are associated with mutations in at least 18 genes that act on the glycosylation of this cell surface receptor rather than the Dag1 gene itself. At the severe end of the disease spectrum, there are substantial structural brain defects, the most striking of which is often cobblestone lissencephaly. The aim of this study was to determine the gene-specific aspects of the dystroglycanopathy brain phenotype through a detailed investigation of the structural brain defects present at birth in three mouse models of dystroglycanopathy-the FKRP(KD) , which has an 80% reduction in Fkrp transcript levels; the Pomgnt1null , which carries a deletion of exons 7-16 of the Pomgnt1 gene; and the Large(myd) mouse, which carries a deletion of exons 5-7 of the Large gene. We show a rostrocaudal and mediolateral gradient in the severity of brain lesions in FKRP(KD) , and to a lesser extent Pomgnt1null mice. Furthermore, the mislocalization of Cajal-Retzius cells is correlated with the gradient of these lesions and the severity of the brain phenotype in these models. Overall these observations implicate gene-specific differences in the pathogenesis of brain lesions in this group of disorders.
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Affiliation(s)
- Helen S Booler
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - Josie L Williams
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - Mark Hopkinson
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - Susan C Brown
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK
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93
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Magri F, Colombo I, Del Bo R, Previtali S, Brusa R, Ciscato P, Scarlato M, Ronchi D, D'Angelo MG, Corti S, Moggio M, Bresolin N, Comi GP. ISPD mutations account for a small proportion of Italian Limb Girdle Muscular Dystrophy cases. BMC Neurol 2015; 15:172. [PMID: 26404900 PMCID: PMC4582941 DOI: 10.1186/s12883-015-0428-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 09/14/2015] [Indexed: 12/16/2022] Open
Abstract
Background Limb Girdle Muscular Dystrophy (LGMD), caused by defective α-dystroglycan (α-DG) glycosylation, was recently associated with mutations in Isoprenoid synthase domain-containing (ISPD) and GDP-mannose pyrophosphorylase B (GMPPB) genes. The frequency of ISPD and GMPPB gene mutations in the LGMD population is unknown. Methods We investigated the contributions of ISPD and GMPPB genes in a cohort of 174 Italian patients with LGMD, including 140 independent probands. Forty-one patients (39 probands) from this cohort had not been genetically diagnosed. The contributions of ISPD and GMPPB were estimated by sequential α-DG immunohistochemistry (IHC) and mutation screening in patients with documented α-DG defect, or by direct DNA sequencing of both genes when muscle tissue was unavailable. Results We performed α-DG IHC in 27/39 undiagnosed probands: 24 subjects had normal α-DG expression, two had a partial deficiency, and one exhibited a complete absence of signal. Direct sequencing of ISPD and GMPPB revealed two heterozygous ISPD mutations in the individual who lacked α-DG IHC signal: c.836-5 T > G (which led to the deletion of exon 6 and the production of an out-of-frame transcript) and c.676 T > C (p.Tyr226His). This patient presented with sural hypertrophy and tip-toed walking at 5 years, developed moderate proximal weakness, and was fully ambulant at 42 years. The remaining 12/39 probands did not exhibit pathogenic sequence variation in either gene. Conclusion ISPD mutations are a rare cause of LGMD in the Italian population, accounting for less than 1 % of the entire cohort studied (FKRP mutations represent 10 %), while GMPPB mutations are notably absent in this patient sample. These data suggest that the genetic heterogeneity of LGMD with and without α-DG defects is greater than previously realized. Electronic supplementary material The online version of this article (doi:10.1186/s12883-015-0428-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Francesca Magri
- Dino Ferrari Centre, Department of Neurological Sciences, University of Milan, I.R.C.C.S. Foundation Cà Granda, Ospedale Maggiore Policlinico, via F. Sforza 35, 20122, Milan, Italy.
| | - Irene Colombo
- Neuromuscular and Rare Disease Unit, Department of Neuroscience, Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, University of Milan, via F. Sforza 35, 20132, Milan, Italy.
| | - Roberto Del Bo
- Dino Ferrari Centre, Department of Neurological Sciences, University of Milan, I.R.C.C.S. Foundation Cà Granda, Ospedale Maggiore Policlinico, via F. Sforza 35, 20122, Milan, Italy.
| | - Stefano Previtali
- Inspe, Division of Neuroscience, San Raffaele, Via Olgettina 60, Milan, Italy.
| | - Roberta Brusa
- Dino Ferrari Centre, Department of Neurological Sciences, University of Milan, I.R.C.C.S. Foundation Cà Granda, Ospedale Maggiore Policlinico, via F. Sforza 35, 20122, Milan, Italy.
| | - Patrizia Ciscato
- Neuromuscular and Rare Disease Unit, Department of Neuroscience, Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, University of Milan, via F. Sforza 35, 20132, Milan, Italy.
| | - Marina Scarlato
- Inspe, Division of Neuroscience, San Raffaele, Via Olgettina 60, Milan, Italy.
| | - Dario Ronchi
- Dino Ferrari Centre, Department of Neurological Sciences, University of Milan, I.R.C.C.S. Foundation Cà Granda, Ospedale Maggiore Policlinico, via F. Sforza 35, 20122, Milan, Italy.
| | | | - Stefania Corti
- Dino Ferrari Centre, Department of Neurological Sciences, University of Milan, I.R.C.C.S. Foundation Cà Granda, Ospedale Maggiore Policlinico, via F. Sforza 35, 20122, Milan, Italy.
| | - Maurizio Moggio
- Neuromuscular and Rare Disease Unit, Department of Neuroscience, Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, University of Milan, via F. Sforza 35, 20132, Milan, Italy.
| | - Nereo Bresolin
- Dino Ferrari Centre, Department of Neurological Sciences, University of Milan, I.R.C.C.S. Foundation Cà Granda, Ospedale Maggiore Policlinico, via F. Sforza 35, 20122, Milan, Italy.
| | - Giacomo Pietro Comi
- Dino Ferrari Centre, Department of Neurological Sciences, University of Milan, I.R.C.C.S. Foundation Cà Granda, Ospedale Maggiore Policlinico, via F. Sforza 35, 20122, Milan, Italy.
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94
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Imamura M, Nakamura A, Mannen H, Takeda S. Characterization of WWP1 protein expression in skeletal muscle of muscular dystrophy chickens. J Biochem 2015; 159:171-9. [PMID: 26314333 DOI: 10.1093/jb/mvv084] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2015] [Accepted: 07/27/2015] [Indexed: 11/14/2022] Open
Abstract
A missense mutation in the gene encoding WWP1 was identified as the most promising candidate responsible for chicken muscular dystrophy (MD) by genetic linkage analysis. WWP1 is a HECT-type E3 ubiquitin protein ligase composed of 922 amino acids, which contains 4 tandem WW domains that interact with the proline-rich peptide motifs of target proteins. The missense mutation changes arginine 441 that is located in the centre of the WW domains into glutamine (R441Q), which potentially affects the function of the WWP1 protein. Here, we show that WWP1 is detected as ∼130-kDa protein that localizes to various structures, such as the plasma membrane (sarcolemma), sarcoplasmic reticulum, mitochondria and nucleus, in normal chicken skeletal muscle. However, in MD chickens, the mutant WWP1 protein was markedly degraded and was absent in the sarcolemma. These changes were also observed in the muscles of chickens in early pre-pathological states. Moreover, in vitro expression analysis showed significant degradation of mutant, but not wild-type WWP1, specifically in myogenic cells. Altogether, our data revealed that the R441Q missense mutation in the WWP1 protein causes degradation and loss of the sarcolemmal localization of WWP1, which may play a role in the pathogenesis of chicken MD.
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Affiliation(s)
- Michihiro Imamura
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1 Ogawahigashi-cho, Kodaira, Tokyo 187-8502, Japan;
| | - Akinori Nakamura
- Intractable Disease Care Center, Shinshu University Hospital, 3-1-1 Asahi, Matsumoto 390-8621, Japan; and
| | - Hideyuki Mannen
- Department of Animal Science, Graduate School of Agricultural Science, Kobe University, Nada, Kobe 657-8501, Japan
| | - Shin'ichi Takeda
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1 Ogawahigashi-cho, Kodaira, Tokyo 187-8502, Japan
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95
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Kim H, Thak EJ, Lee DJ, Agaphonov MO, Kang HA. Hansenula polymorpha Pmt4p Plays Critical Roles in O-Mannosylation of Surface Membrane Proteins and Participates in Heteromeric Complex Formation. PLoS One 2015; 10:e0129914. [PMID: 26134523 PMCID: PMC4489896 DOI: 10.1371/journal.pone.0129914] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 05/14/2015] [Indexed: 01/09/2023] Open
Abstract
O-mannosylation, the addition of mannose to serine and threonine residues of secretory proteins, is a highly conserved post-translational modification found in organisms ranging from bacteria to humans. Here, we report the functional and molecular characterization of the HpPMT4 gene encoding a protein O-mannosyltransferase in the thermotolerant methylotrophic yeast Hansenula polymorpha, an emerging host for the production of therapeutic recombinant proteins. Compared to the deletion of HpPMT1, deletion of another major PMT gene, HpPMT4, resulted in more increased sensitivity to the antibiotic hygromycin B, caffeine, and osmotic stresses, but did not affect the thermotolerance of H. polymorpha. Notably, the deletion of HpPMT4 generated severe defects in glycosylation of the surface sensor proteins HpWsc1p and HpMid2p, with marginal effects on secreted glycoproteins such as chitinase and HpYps1p lacking a GPI anchor. However, despite the severely impaired mannosylation of surface sensor proteins in the Hppmt4∆ mutant, the phosphorylation of HpMpk1p and HpHog1p still showed a high increase upon treatment with cell wall disturbing agents or high concentrations of salts. The conditional Hppmt1pmt4∆ double mutant strains displayed severely impaired growth, enlarged cell size, and aberrant cell separation, implying that the loss of HpPMT4 function might be lethal to cells in the absence of HpPmt1p. Moreover, the HpPmt4 protein was found to form not only a homomeric complex but also a heteromeric complex with either HpPmt1p or HpPmt2p. Altogether, our results support the function of HpPmt4p as a key player in O-mannosylation of cell surface proteins and its participation in the formation of heterodimers with other PMT members, besides homodimer formation, in H. polymorpha.
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Affiliation(s)
- Hyunah Kim
- Department of Life Science, Chung-Ang University, Seoul 156–756, Korea
| | - Eun Jung Thak
- Department of Life Science, Chung-Ang University, Seoul 156–756, Korea
| | - Dong-Jik Lee
- Department of Life Science, Chung-Ang University, Seoul 156–756, Korea
| | - Michael O. Agaphonov
- A.N. Bach Institute of Biochemistry of the Russian Academy of Sciences, Moscow, Russia
| | - Hyun Ah Kang
- Department of Life Science, Chung-Ang University, Seoul 156–756, Korea
- * E-mail:
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96
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Restoration of Functional Glycosylation of α-Dystroglycan in FKRP Mutant Mice Is Associated with Muscle Regeneration. THE AMERICAN JOURNAL OF PATHOLOGY 2015; 185:2025-37. [DOI: 10.1016/j.ajpath.2015.03.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 03/19/2015] [Accepted: 03/23/2015] [Indexed: 11/19/2022]
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97
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Yoshida-Moriguchi T, Campbell KP. Matriglycan: a novel polysaccharide that links dystroglycan to the basement membrane. Glycobiology 2015; 25:702-13. [PMID: 25882296 PMCID: PMC4453867 DOI: 10.1093/glycob/cwv021] [Citation(s) in RCA: 154] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 04/08/2015] [Indexed: 01/01/2023] Open
Abstract
Associations between cells and the basement membrane are critical for a variety of biological events including cell proliferation, cell migration, cell differentiation and the maintenance of tissue integrity. Dystroglycan is a highly glycosylated basement membrane receptor, and is involved in physiological processes that maintain integrity of the skeletal muscle, as well as development and function of the central nervous system. Aberrant O-glycosylation of the α subunit of this protein, and a concomitant loss of dystroglycan's ability to function as a receptor for extracellular matrix (ECM) ligands that bear laminin globular (LG) domains, occurs in several congenital/limb-girdle muscular dystrophies (also referred to as dystroglycanopathies). Recent genetic studies revealed that mutations in DAG1 (which encodes dystroglycan) and at least 17 other genes disrupt the ECM receptor function of dystroglycan and cause disease. Here, we summarize recent advances in our understanding of the enzymatic functions of two of these disease genes: the like-glycosyltransferase (LARGE) and protein O-mannose kinase (POMK, previously referred to as SGK196). In addition, we discuss the structure of the glycan that directly binds the ECM ligands and the mechanisms by which this functional motif is linked to dystroglycan. In light of the fact that dystroglycan functions as a matrix receptor and the polysaccharide synthesized by LARGE is the binding motif for matrix proteins, we propose to name this novel polysaccharide structure matriglycan.
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Affiliation(s)
- Takako Yoshida-Moriguchi
- Howard Hughes Medical Institute, Department of Molecular Physiology and Biophysics, Department of Neurology, Department of Internal Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, 4283 Carver Biomedical Research Building, 285 Newton Road, Iowa City, IA 52242-1101, USA
| | - Kevin P Campbell
- Howard Hughes Medical Institute, Department of Molecular Physiology and Biophysics, Department of Neurology, Department of Internal Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, 4283 Carver Biomedical Research Building, 285 Newton Road, Iowa City, IA 52242-1101, USA
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98
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Congenital disorders of glycosylation: a concise chart of glycocalyx dysfunction. Trends Biochem Sci 2015; 40:377-84. [PMID: 25840516 DOI: 10.1016/j.tibs.2015.03.002] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 01/26/2015] [Accepted: 03/04/2015] [Indexed: 12/28/2022]
Abstract
Glycosylation is a ubiquitous modification of lipids and proteins. Despite the essential contribution of glycoconjugates to the viability of all living organisms, diseases of glycosylation in humans have only been identified over the past few decades. The recent development of next-generation DNA sequencing techniques has accelerated the pace of discovery of novel glycosylation defects. The description of multiple mutations across glycosylation pathways not only revealed tremendous diversity in functional impairments, but also pointed to phenotypic similarities, emphasizing the interconnected flow of substrates underlying glycan assembly. The current list of 100 known glycosylation disorders provides an overview of the significance of glycosylation in human development and physiology.
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99
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Awano H, Blaeser A, Wu B, Lu P, Keramaris-Vrantsis E, Lu Q. Dystroglycanopathy muscles lacking functional glycosylation of alpha-dystroglycan retain regeneration capacity. Neuromuscul Disord 2015; 25:474-84. [PMID: 25937147 DOI: 10.1016/j.nmd.2015.03.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 02/03/2015] [Accepted: 03/11/2015] [Indexed: 12/27/2022]
Abstract
In dystroglycanopathies, lack of glycosylated alpha-dystroglycan (α-DG) alters membrane fragility leading to fiber damage and repetitive cycles of muscle degeneration and regeneration. However the effect of the glycosylation of α-DG on muscle regeneration is not clearly understood. In this study, we examined the regenerative capacity of dystrophic muscles in vivo in FKRP mutant and LARGE(myd) mice with little and complete lack of functionally glycosylated α-DG (F-α-DG) respectively. The number of regenerating fibers expressing embryonic myosin heavy chain (eMyHC) in the diseased muscles up to the age of 10 months is higher than or at similar levels to wild type muscle after notexin and polyethyleminine insults. The process of fiber maturation is not significantly affected by the lack of F-α-DG assessed by size distribution. The earlier appearance of a larger number of regenerating fibers after injury is consistent with the observation that the populations of myogenic satellite cells are increased and being readily activated in the dystroglycanopathy muscles. F-α-DG is expressed at trace amounts in undifferentiated myoblasts, but increases in differentiated myotubes in vitro. We therefore conclude that muscle regeneration is not impaired in the early stage of the dystroglycanopathies, and F-α-DG does not play a significant role in myogenic cell proliferation and fiber formation and maturation.
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Affiliation(s)
- Hiroyuki Awano
- McColl-Lockwood Laboratory for Muscular Dystrophy Research, Cannon Research Center, Carolinas Medical Center, 1000 Blythe Blvd, Charlotte, NC 28203, USA
| | - Anthony Blaeser
- McColl-Lockwood Laboratory for Muscular Dystrophy Research, Cannon Research Center, Carolinas Medical Center, 1000 Blythe Blvd, Charlotte, NC 28203, USA
| | - Bo Wu
- McColl-Lockwood Laboratory for Muscular Dystrophy Research, Cannon Research Center, Carolinas Medical Center, 1000 Blythe Blvd, Charlotte, NC 28203, USA
| | - Pei Lu
- McColl-Lockwood Laboratory for Muscular Dystrophy Research, Cannon Research Center, Carolinas Medical Center, 1000 Blythe Blvd, Charlotte, NC 28203, USA
| | - Elizabeth Keramaris-Vrantsis
- McColl-Lockwood Laboratory for Muscular Dystrophy Research, Cannon Research Center, Carolinas Medical Center, 1000 Blythe Blvd, Charlotte, NC 28203, USA
| | - Qi Lu
- McColl-Lockwood Laboratory for Muscular Dystrophy Research, Cannon Research Center, Carolinas Medical Center, 1000 Blythe Blvd, Charlotte, NC 28203, USA.
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100
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Dwyer CA, Katoh T, Tiemeyer M, Matthews RT. Neurons and glia modify receptor protein-tyrosine phosphatase ζ (RPTPζ)/phosphacan with cell-specific O-mannosyl glycans in the developing brain. J Biol Chem 2015; 290:10256-73. [PMID: 25737452 DOI: 10.1074/jbc.m114.614099] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Indexed: 01/06/2023] Open
Abstract
Protein O-mannosylation is a glycan modification that is required for normal nervous system development and function. Mutations in genes involved in protein O-mannosyl glycosylation give rise to a group of neurodevelopmental disorders known as congenital muscular dystrophies (CMDs) with associated CNS abnormalities. Our previous work demonstrated that receptor protein-tyrosine phosphatase ζ (RPTPζ)/phosphacan is hypoglycosylated in a mouse model of one of these CMDs, known as muscle-eye-brain disease, a disorder that is caused by loss of an enzyme (protein O-mannose β-1,2-N-acetylglucosaminyltransferase 1) that modifies O-mannosyl glycans. In addition, monoclonal antibodies Cat-315 and 3F8 were demonstrated to detect O-mannosyl glycan modifications on RPTPζ/phosphacan. Here, we show that O-mannosyl glycan epitopes recognized by these antibodies define biochemically distinct glycoforms of RPTPζ/phosphacan and that these glycoforms differentially decorate the surface of distinct populations of neural cells. To provide a further structural basis for immunochemically based glycoform differences, we characterized the O-linked glycan heterogeneity of RPTPζ/phosphacan in the early postnatal mouse brain by multidimensional mass spectrometry. Structural characterization of the O-linked glycans released from purified RPTPζ/phosphacan demonstrated that this protein is a significant substrate for protein O-mannosylation and led to the identification of several novel O-mannose-linked glycan structures, including sulfo-N-acetyllactosamine containing modifications. Taken together, our results suggest that specific glycan modifications may tailor the function of this protein to the unique needs of specific cells. Furthermore, their absence in CMDs suggests that hypoglycosylation of RPTPζ/phosphacan may have different functional consequences in neurons and glia.
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Affiliation(s)
- Chrissa A Dwyer
- From the Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, New York 13210 and
| | - Toshihiko Katoh
- the Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602
| | - Michael Tiemeyer
- the Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602
| | - Russell T Matthews
- From the Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, New York 13210 and
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