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Bartek V, Szabó I, Harmath Á, Rudas G, Steiner T, Fintha A, Ács N, Beke A. Prenatal and Postnatal Diagnosis and Genetic Background of Corpus Callosum Malformations and Neonatal Follow-Up. CHILDREN (BASEL, SWITZERLAND) 2024; 11:797. [PMID: 39062246 PMCID: PMC11274835 DOI: 10.3390/children11070797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 06/24/2024] [Accepted: 06/27/2024] [Indexed: 07/28/2024]
Abstract
INTRODUCTION The corpus callosum is one of the five main cerebral commissures. It is key to combining sensory and motor functions. Its structure can be pathological (dysgenesis) or completely absent (agenesis). The corpus callosum dys- or agenesis is a rare disease (1:4000 live births), but it can have serious mental effects. METHODS In our study, we processed the data of 64 pregnant women. They attended a prenatal diagnostic center and genetic counseling from 2005 to 2019 at the Department of Obstetrics and Gynecology at Semmelweis University. RESULTS The pregnancies had the following outcomes: 52 ended in delivery, 1 in spontaneous abortion, and 11 in termination of pregnancy (TOP) cases (n = 64). The average time of detection with imaging tests was 25.24 gestational weeks. In 16 cases, prenatal magnetic resonance imaging (MRI) was performed. If the abnormality was detected before the 20th week, a genetic test was performed on an amniotic fluid sample obtained from a genetic amniocentesis. Karyotyping and cytogenetic tests were performed in 15 of the investigated cases. Karyotyping gave normal results in three cases (46,XX or XY). In one of these cases, postnatally chromosomal microarray (CMA) was later performed, which confirmed Aicardi syndrome (3q21.3-21.1 microdeletion). In one case, postnatally, the test found Wiedemann-Rautenstrauch syndrome. In other cases, it found X ring, Di George syndrome, 46,XY,del(13q)(q13q22) and 46,XX,del(5p)(p13) (Cri-du-chat syndrome). Edwards syndrome was diagnosed in six cases, and Patau syndrome in one case. CONCLUSIONS We found that corpus callosum abnormalities are often linked to chromosomal problems. We recommend that a cytogenetic test be performed in all cases to rule out inherited diseases. Also, the long-term outcome does not just depend on the disease's severity and the associated other conditions, and hence proper follow-up and early development are also key. For this reason, close teamwork between neonatology, developmental neurology, and pediatric surgery is vital.
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Affiliation(s)
- Virág Bartek
- Department of Obstetrics and Gynecology, Semmelweis University, 1085 Budapest, Hungary; (V.B.); (I.S.); (Á.H.); (T.S.); (N.Á.)
| | - István Szabó
- Department of Obstetrics and Gynecology, Semmelweis University, 1085 Budapest, Hungary; (V.B.); (I.S.); (Á.H.); (T.S.); (N.Á.)
| | - Ágnes Harmath
- Department of Obstetrics and Gynecology, Semmelweis University, 1085 Budapest, Hungary; (V.B.); (I.S.); (Á.H.); (T.S.); (N.Á.)
| | - Gábor Rudas
- Heim Pál National Pediatric Institute, 1089 Budapest, Hungary;
| | - Tidhar Steiner
- Department of Obstetrics and Gynecology, Semmelweis University, 1085 Budapest, Hungary; (V.B.); (I.S.); (Á.H.); (T.S.); (N.Á.)
| | - Attila Fintha
- Department of Pathology and Experimental Cancer Research, Semmelweis University, 1085 Budapest, Hungary;
| | - Nándor Ács
- Department of Obstetrics and Gynecology, Semmelweis University, 1085 Budapest, Hungary; (V.B.); (I.S.); (Á.H.); (T.S.); (N.Á.)
| | - Artúr Beke
- Department of Obstetrics and Gynecology, Semmelweis University, 1085 Budapest, Hungary; (V.B.); (I.S.); (Á.H.); (T.S.); (N.Á.)
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Tan RL, Sciandra F, Hübner W, Bozzi M, Reimann J, Schoch S, Brancaccio A, Blaess S. The missense mutation C667F in murine β-dystroglycan causes embryonic lethality, myopathy and blood-brain barrier destabilization. Dis Model Mech 2024; 17:dmm050594. [PMID: 38616731 PMCID: PMC11212641 DOI: 10.1242/dmm.050594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 04/08/2024] [Indexed: 04/16/2024] Open
Abstract
Dystroglycan (DG) is an extracellular matrix receptor consisting of an α- and a β-DG subunit encoded by the DAG1 gene. The homozygous mutation (c.2006G>T, p.Cys669Phe) in β-DG causes muscle-eye-brain disease with multicystic leukodystrophy in humans. In a mouse model of this primary dystroglycanopathy, approximately two-thirds of homozygous embryos fail to develop to term. Mutant mice that are born undergo a normal postnatal development but show a late-onset myopathy with partially penetrant histopathological changes and an impaired performance on an activity wheel. Their brains and eyes are structurally normal, but the localization of mutant β-DG is altered in the glial perivascular end-feet, resulting in a perturbed protein composition of the blood-brain and blood-retina barrier. In addition, α- and β-DG protein levels are significantly reduced in muscle and brain of mutant mice. Owing to the partially penetrant developmental phenotype of the C669F β-DG mice, they represent a novel and highly valuable mouse model with which to study the molecular effects of β-DG functional alterations both during embryogenesis and in mature muscle, brain and eye, and to gain insight into the pathogenesis of primary dystroglycanopathies.
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Affiliation(s)
- Rui Lois Tan
- Neurodevelopmental Genetics, Institute of Reconstructive Neurobiology, Medical Faculty, University of Bonn, 53127 Bonn, Germany
| | - Francesca Sciandra
- Institute of Chemical Sciences and Technologies ‘Giulio Natta’ (SCITEC)-CNR, 00168 Rome, Italy
| | - Wolfgang Hübner
- Biomolecular Photonics, Faculty of Physics, Bielefeld University, 33615 Bielefeld, Germany
| | - Manuela Bozzi
- Institute of Chemical Sciences and Technologies ‘Giulio Natta’ (SCITEC)-CNR, 00168 Rome, Italy
- Dipartimento di Scienze Biotecnologiche di Base, Cliniche Intensivologiche e Perioperatorie. Sezione di Biochimica. Università Cattolica del Sacro Cuore di Roma, 00168 Rome, Italy
| | - Jens Reimann
- Department of Neurology, Neuromuscular Diseases Section, University Hospital Bonn, 53127 Bonn, Germany
| | - Susanne Schoch
- Synaptic Neuroscience Team, Institute of Neuropathology, Medical Faculty, University of Bonn, 53127 Bonn, Germany
| | - Andrea Brancaccio
- Institute of Chemical Sciences and Technologies ‘Giulio Natta’ (SCITEC)-CNR, 00168 Rome, Italy
- School of Biochemistry, University Walk, University of Bristol, Bristol BS8 1TD, UK
| | - Sandra Blaess
- Neurodevelopmental Genetics, Institute of Reconstructive Neurobiology, Medical Faculty, University of Bonn, 53127 Bonn, Germany
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Sciandra F, Desiderio C, Vincenzoni F, Viscuso S, Bozzi M, Hübner W, Jimenez-Gutierrez GE, Cisneros B, Brancaccio A. Analysis of the GFP-labelled β-dystroglycan interactome in HEK-293 transfected cells reveals novel intracellular networks. Biochem Biophys Res Commun 2024; 703:149656. [PMID: 38364681 DOI: 10.1016/j.bbrc.2024.149656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 01/19/2024] [Accepted: 02/06/2024] [Indexed: 02/18/2024]
Abstract
Dystroglycan (DG) is a cell adhesion complex that is widely expressed in tissues. It is composed by two subunits, α-DG, a highly glycosylated protein that interacts with several extracellular matrix proteins, and transmembrane β-DG whose, cytodomain binds to the actin cytoskeleton. Glycosylation of α-DG is crucial for functioning as a receptor for its multiple extracellular binding partners. Perturbation of α-DG glycosylation is the central event in the pathogenesis of severe pathologies such as muscular dystrophy and cancer. β-DG acts as a scaffold for several cytoskeletal and nuclear proteins and very little is known about the fine regulation of some of these intracellular interactions and how they are perturbed in diseases. To start filling this gap by identifying uncharacterized intracellular networks preferentially associated with β-DG, HEK-293 cells were transiently transfected with a plasmid carrying the β-DG subunit with GFP fused at its C-terminus. With this strategy, we aimed at forcing β-DG to occupy multiple intracellular locations instead of sitting tightly at its canonical plasma membrane milieu, where it is commonly found in association with α-DG. Immunoprecipitation by anti-GFP antibodies followed by shotgun proteomic analysis led to the identification of an interactome formed by 313 exclusive protein matches for β-DG binding. A series of already known β-DG interactors have been found, including ezrin and emerin, whilst significant new matches, which include potential novel β-DG interactors and their related networks, were identified in diverse subcellular compartments, such as cytoskeleton, endoplasmic reticulum/Golgi, mitochondria, nuclear membrane and the nucleus itself. Of particular interest amongst the novel identified matches, Lamina-Associated Polypeptide-1B (LAP1B), an inner nuclear membrane protein, whose mutations are known to cause nuclear envelopathies characterized by muscular dystrophy, was found to interact with β-DG in HEK-293 cells. This evidence was confirmed by immunoprecipitation, Western blotting and immunofluorescence experiments. We also found by immunofluorescence experiments that LAP1B looses its nuclear envelope localization in C2C12 DG-knock-out cells, suggesting that LAP1B requires β-DG for a proper nuclear localization. These results expand the role of β-DG as a nuclear scaffolding protein and provide novel evidence of a possible link between dystroglycanopathies and nuclear envelopathies displaying with muscular dystrophy.
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Affiliation(s)
- Francesca Sciandra
- Istituto di Scienze e Tecnologie Chimiche "Giulio Natta"- SCITEC (CNR), Largo F. Vito, 00168, Roma, Italy
| | - Claudia Desiderio
- Istituto di Scienze e Tecnologie Chimiche "Giulio Natta"- SCITEC (CNR), Largo F. Vito, 00168, Roma, Italy
| | - Federica Vincenzoni
- Dipartimento di Scienze biotecnologiche di base, cliniche intensivologiche e perioperatorie, Sezione di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168, Roma, Italy; Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma, Italy
| | - Simona Viscuso
- Dipartimento di Scienze biotecnologiche di base, cliniche intensivologiche e perioperatorie, Sezione di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168, Roma, Italy
| | - Manuela Bozzi
- Istituto di Scienze e Tecnologie Chimiche "Giulio Natta"- SCITEC (CNR), Largo F. Vito, 00168, Roma, Italy; Dipartimento di Scienze biotecnologiche di base, cliniche intensivologiche e perioperatorie, Sezione di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168, Roma, Italy
| | - Wolfgang Hübner
- Biomolecular Photonics, University of Bielefeld, 33615, Bielefeld, Germany
| | | | - Bulmaro Cisneros
- Departamento de Genética y Biología Molecular, CINVESTAV Zacatenco IPN, Ciudad de México, 07360, Mexico
| | - Andrea Brancaccio
- Istituto di Scienze e Tecnologie Chimiche "Giulio Natta"- SCITEC (CNR), Largo F. Vito, 00168, Roma, Italy; School of Biochemistry, University of Bristol, BS8 1TD, UK.
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Traverso M, Baratto S, Iacomino M, Di Duca M, Panicucci C, Casalini S, Grandis M, Falace A, Torella A, Picillo E, Onore ME, Politano L, Nigro V, Innes AM, Barresi R, Bruno C, Zara F, Fiorillo C, Scala M. DAG1 haploinsufficiency is associated with sporadic and familial isolated or pauci-symptomatic hyperCKemia. Eur J Hum Genet 2024; 32:342-349. [PMID: 38177406 PMCID: PMC10923780 DOI: 10.1038/s41431-023-01516-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 10/31/2023] [Accepted: 11/27/2023] [Indexed: 01/06/2024] Open
Abstract
DAG1 encodes for dystroglycan, a key component of the dystrophin-glycoprotein complex (DGC) with a pivotal role in skeletal muscle function and maintenance. Biallelic loss-of-function DAG1 variants cause severe muscular dystrophy and muscle-eye-brain disease. A possible contribution of DAG1 deficiency to milder muscular phenotypes has been suggested. We investigated the genetic background of twelve subjects with persistent mild-to-severe hyperCKemia to dissect the role of DAG1 in this condition. Genetic testing was performed through exome sequencing (ES) or custom NGS panels including various genes involved in a spectrum of muscular disorders. Histopathological and Western blot analyses were performed on muscle biopsy samples obtained from three patients. We identified seven novel heterozygous truncating variants in DAG1 segregating with isolated or pauci-symptomatic hyperCKemia in all families. The variants were rare and predicted to lead to nonsense-mediated mRNA decay or the formation of a truncated transcript. In four cases, DAG1 variants were inherited from similarly affected parents. Histopathological analysis revealed a decreased expression of dystroglycan subunits and Western blot confirmed a significantly reduced expression of beta-dystroglycan in muscle samples. This study supports the pathogenic role of DAG1 haploinsufficiency in isolated or pauci-symptomatic hyperCKemia, with implications for clinical management and genetic counseling.
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Affiliation(s)
- Monica Traverso
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Serena Baratto
- Centre of Translational and Experimental Myology, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Michele Iacomino
- Medical Genetics Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Marco Di Duca
- Medical Genetics Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Chiara Panicucci
- Centre of Translational and Experimental Myology, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Sara Casalini
- Centre of Translational and Experimental Myology, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | | | - Antonio Falace
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Annalaura Torella
- Department of Precision Medicine, University "Luigi Vanvitelli", Naples, Italy
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
| | - Esther Picillo
- Department of Precision Medicine, University "Luigi Vanvitelli", Naples, Italy
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
| | - Maria Elena Onore
- Department of Precision Medicine, University "Luigi Vanvitelli", Naples, Italy
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
| | - Luisa Politano
- Department of Precision Medicine, University "Luigi Vanvitelli", Naples, Italy
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
| | - Vincenzo Nigro
- Department of Precision Medicine, University "Luigi Vanvitelli", Naples, Italy
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
| | - A Micheil Innes
- Department of Medical Genetics and Pediatrics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | | | - Claudio Bruno
- Centre of Translational and Experimental Myology, IRCCS Istituto Giannina Gaslini, Genoa, Italy
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | - Federico Zara
- Medical Genetics Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy.
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy.
| | - Chiara Fiorillo
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy.
- Child Neuropsychiatry Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy.
| | - Marcello Scala
- Medical Genetics Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy.
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy.
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Hang J, Wang J, Lu M, Xue Y, Qiao J, Tao L. Protein O-mannosylation across kingdoms and related diseases: From glycobiology to glycopathology. Biomed Pharmacother 2022; 148:112685. [PMID: 35149389 DOI: 10.1016/j.biopha.2022.112685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 01/29/2022] [Accepted: 02/01/2022] [Indexed: 11/18/2022] Open
Abstract
The post-translational glycosylation of proteins by O-linked α-mannose is conserved from bacteria to humans. Due to advances in high-throughput mass spectrometry-based approaches, a variety of glycoproteins are identified to be O-mannosylated. Various proteins with O-mannosylation are involved in biological processes, providing essential necessity for proper growth and development. In this review, we summarize the process and regulation of O-mannosylation. The multi-step O-mannosylation procedures are quite dynamic and complex, especially when considering the structural and functional inspection of the involved enzymes. The widely studied O-mannosylated proteins in human include α-Dystroglycan (α-DG), cadherins, protocadherins, and plexin, and their aberrant O-mannosylation are associated with many diseases. In addition, O-mannosylation also contributes to diverse functions in lower eukaryotes and prokaryotes. Finally, we present the relationship between O-mannosylation and gut microbiota (GM), and elucidate that O-mannosylation in microbiome is of great importance in the dynamic balance of GM. Our study provides an overview of the processes of O-mannosylation in mammalian cells and other organisms, and also associated regulated enzymes and biological functions, which could contribute to the understanding of newly discovered O-mannosylated glycoproteins.
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Affiliation(s)
- Jing Hang
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing 100191, China; National Clinical Research Center for Obstetrics and Gynecology (Peking University Third Hospital), Beijing 100191, China; Key Laboratory of Assisted Reproduction (Peking University), Ministry of Education, Beijing 100191, China; Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology, Beijing 100191, China
| | - Jinpeng Wang
- Department of Orthopedics, First Hospital of China Medical University, Shenyang 110001, China
| | - Minzhen Lu
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing 100191, China; National Clinical Research Center for Obstetrics and Gynecology (Peking University Third Hospital), Beijing 100191, China; Key Laboratory of Assisted Reproduction (Peking University), Ministry of Education, Beijing 100191, China; Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology, Beijing 100191, China
| | - Yuchuan Xue
- The First Department of Clinical Medicine, China Medical University, Shenyang 110001, China
| | - Jie Qiao
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing 100191, China; National Clinical Research Center for Obstetrics and Gynecology (Peking University Third Hospital), Beijing 100191, China; Key Laboratory of Assisted Reproduction (Peking University), Ministry of Education, Beijing 100191, China; Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology, Beijing 100191, China.
| | - Lin Tao
- Department of Orthopedics, First Hospital of China Medical University, Shenyang 110001, China.
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Fan L, Miura S, Shimojo T, Sugino H, Fujioka R, Shibata H. A novel 1-bp deletion variant in DAG1 in Japanese familial asymptomatic hyper-CK-emia. Hum Genome Var 2022; 9:4. [PMID: 35082294 PMCID: PMC8791931 DOI: 10.1038/s41439-022-00182-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 12/27/2021] [Accepted: 01/05/2022] [Indexed: 01/11/2023] Open
Abstract
Asymptomatic hyper-CK-emia (ASCK) is characterized by persistent elevation of creatine kinase (CK) in serum without any neurological symptoms. We ascertained a two-generation family of ASCK patients without clear neurological abnormalities except for the high levels of serum CK (810.5 ± 522.4 U/L). We identified a novel 1-bp deletion variant in the DAG1 gene shared by the patients in the family (NM_001177639: exon 3: c.930delC:p.R311Gfs*70). The variant causes premature termination of translation at codon 477, resulting in a protein product completely devoid of the essential DAG1 domain. Since ASCK has been associated with DAG1 in only one case carrying compound heterozygous missense variants, our new finding of a novel 1-bp deletion revealed the previously unknown dominant effect of DAG1 on ASCK.
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Affiliation(s)
- Luoming Fan
- grid.177174.30000 0001 2242 4849Division of Genomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Shiroh Miura
- grid.255464.40000 0001 1011 3808Department of Neurology and Geriatric Medicine, Ehime University Graduate School of Medicine, Ehime, Japan
| | - Tomofumi Shimojo
- grid.177174.30000 0001 2242 4849Division of Genomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | | | - Ryuta Fujioka
- grid.443342.60000 0001 0664 6230Department of Food and Nutrition, Beppu University Junior College, Oita, Japan
| | - Hiroki Shibata
- grid.177174.30000 0001 2242 4849Division of Genomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
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Cuttler K, Hassan M, Carr J, Cloete R, Bardien S. Emerging evidence implicating a role for neurexins in neurodegenerative and neuropsychiatric disorders. Open Biol 2021; 11:210091. [PMID: 34610269 PMCID: PMC8492176 DOI: 10.1098/rsob.210091] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Synaptopathies are brain disorders characterized by dysfunctional synapses, which are specialized junctions between neurons that are essential for the transmission of information. Synaptic dysfunction can occur due to mutations that alter the structure and function of synaptic components or abnormal expression levels of a synaptic protein. One class of synaptic proteins that are essential to their biology are cell adhesion proteins that connect the pre- and post-synaptic compartments. Neurexins are one type of synaptic cell adhesion molecule that have, recently, gained more pathological interest. Variants in both neurexins and their common binding partners, neuroligins, have been associated with several neuropsychiatric disorders. In this review, we summarize some of the key physiological functions of the neurexin protein family and the protein networks they are involved in. Furthermore, examination of published literature has implicated neurexins in both neuropsychiatric and neurodegenerative disorders. There is a clear link between neurexins and neuropsychiatric disorders, such as autism spectrum disorder and schizophrenia. However, multiple expression studies have also shown changes in neurexin expression in several neurodegenerative disorders, including Alzheimer's disease and Parkinson's disease. Therefore, this review highlights the potential importance of neurexins in brain disorders and the importance of doing more targeted studies on these genes and proteins.
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Affiliation(s)
- Katelyn Cuttler
- Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, Stellenbosch University, Cape Town, South Africa
| | - Maryam Hassan
- South African Medical Research Council Bioinformatics Unit, South African National Bioinformatics Institute, University of the Western Cape, Cape Town, South Africa
| | - Jonathan Carr
- Division of Neurology, Department of Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa,South African Medical Research Council/Stellenbosch University Genomics of Brain Disorders Research Unit, Cape Town, South Africa
| | - Ruben Cloete
- South African Medical Research Council Bioinformatics Unit, South African National Bioinformatics Institute, University of the Western Cape, Cape Town, South Africa
| | - Soraya Bardien
- Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, Stellenbosch University, Cape Town, South Africa,South African Medical Research Council/Stellenbosch University Genomics of Brain Disorders Research Unit, Cape Town, South Africa
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McGrath MJ, Eramo MJ, Gurung R, Sriratana A, Gehrig SM, Lynch GS, Lourdes SR, Koentgen F, Feeney SJ, Lazarou M, McLean CA, Mitchell CA. Defective lysosome reformation during autophagy causes skeletal muscle disease. J Clin Invest 2021; 131:135124. [PMID: 33119550 PMCID: PMC7773396 DOI: 10.1172/jci135124] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 09/23/2020] [Indexed: 12/17/2022] Open
Abstract
The regulation of autophagy-dependent lysosome homeostasis in vivo is unclear. We showed that the inositol polyphosphate 5-phosphatase INPP5K regulates autophagic lysosome reformation (ALR), a lysosome recycling pathway, in muscle. INPP5K hydrolyzes phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2] to phosphatidylinositol 4-phosphate [PI(4)P], and INPP5K mutations cause muscular dystrophy by unknown mechanisms. We report that loss of INPP5K in muscle caused severe disease, autophagy inhibition, and lysosome depletion. Reduced PI(4,5)P2 turnover on autolysosomes in Inpp5k–/– muscle suppressed autophagy and lysosome repopulation via ALR inhibition. Defective ALR in Inpp5k–/– myoblasts was characterized by enlarged autolysosomes and the persistence of hyperextended reformation tubules, structures that participate in membrane recycling to form lysosomes. Reduced disengagement of the PI(4,5)P2 effector clathrin was observed on reformation tubules, which we propose interfered with ALR completion. Inhibition of PI(4,5)P2 synthesis or expression of WT INPP5K but not INPP5K disease mutants in INPP5K-depleted myoblasts restored lysosomal homeostasis. Therefore, bidirectional interconversion of PI(4)P/PI(4,5)P2 on autolysosomes was integral to lysosome replenishment and autophagy function in muscle. Activation of TFEB-dependent de novo lysosome biogenesis did not compensate for loss of ALR in Inpp5k–/– muscle, revealing a dependence on this lysosome recycling pathway. Therefore, in muscle, ALR is indispensable for lysosome homeostasis during autophagy and when defective is associated with muscular dystrophy.
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Affiliation(s)
- Meagan J McGrath
- Cancer Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Melbourne, Victoria, Australia
| | - Matthew J Eramo
- Cancer Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Melbourne, Victoria, Australia
| | - Rajendra Gurung
- Cancer Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Melbourne, Victoria, Australia
| | - Absorn Sriratana
- Cancer Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Melbourne, Victoria, Australia
| | - Stefan M Gehrig
- Centre for Muscle Research, Department of Physiology, School of Biomedical Sciences, The University of Melbourne, Melbourne, Victoria, Australia
| | - Gordon S Lynch
- Centre for Muscle Research, Department of Physiology, School of Biomedical Sciences, The University of Melbourne, Melbourne, Victoria, Australia
| | - Sonia Raveena Lourdes
- Cancer Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Melbourne, Victoria, Australia
| | - Frank Koentgen
- Ozgene Pty Ltd, Bentley, Perth, Western Australia, Australia
| | - Sandra J Feeney
- Cancer Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Melbourne, Victoria, Australia
| | - Michael Lazarou
- Neuroscience Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Melbourne, Victoria, Australia
| | - Catriona A McLean
- Department of Anatomical Pathology, Alfred Hospital, Prahran, Melbourne, Victoria, Australia
| | - Christina A Mitchell
- Cancer Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Melbourne, Victoria, Australia
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Yang JY, Halmo SM, Praissman J, Chapla D, Singh D, Wells L, Moremen KW, Lanzilotta WN. Crystal structures of β-1,4-N-acetylglucosaminyltransferase 2: structural basis for inherited muscular dystrophies. Acta Crystallogr D Struct Biol 2021; 77:486-495. [PMID: 33825709 PMCID: PMC8025878 DOI: 10.1107/s2059798321001261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 02/02/2021] [Indexed: 11/11/2022] Open
Abstract
The canonical O-mannosylation pathway in humans is essential for the functional glycosylation of α-dystroglycan. Disruption of this post-translational modification pathway leads to congenital muscular dystrophies. The first committed step in the construction of a functional matriglycan structure involves the post-translational modification of α-dystroglycan. This is essential for binding extracellular matrix proteins and arenaviruses, and is catalyzed by β-1,4-N-acetylglucosaminyltransferase 2 (POMGNT2). While another glycosyl transferase, β-1,4-N-acetylglucosaminyltransferase 1 (POMGNT1), has been shown to be promiscuous in extending O-mannosylated sites, POMGNT2 has been shown to display significant primary amino-acid selectivity near the site of O-mannosylation. Moreover, several single point mutations in POMGNT2 have been identified in patients with assorted dystroglycanopathies such as Walker-Warburg syndrome and limb girdle muscular dystrophy. To gain insight into POMGNT2 function in humans, the enzyme was expressed as a soluble, secreted fusion protein by transient infection of HEK293 suspension cultures. Here, crystal structures of POMGNT2 (amino-acid residues 25-580) with and without UDP bound are reported. Consistent with a novel fold and a unique domain organization, no molecular-replacement model was available and phases were obtained through crystallization of a selenomethionine variant of the enzyme in the same space group. Tetragonal (space group P4212; unit-cell parameters a = b = 129.8, c = 81.6 Å, α = γ = β = 90°) crystals with UDP bound diffracted to 1.98 Å resolution and contained a single monomer in the asymmetric unit. Orthorhombic (space group P212121; unit-cell parameters a = 142.3, b = 153.9, c = 187.4 Å, α = γ = β = 90°) crystals were also obtained; they diffracted to 2.57 Å resolution and contained four monomers with differential glycosylation patterns and conformations. These structures provide the first rational basis for an explanation of the loss-of-function mutations and offer significant insights into the mechanics of this important human enzyme.
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Affiliation(s)
- Jeong Yeh Yang
- The Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Stephanie M. Halmo
- The Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Jeremy Praissman
- The Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Digantkumar Chapla
- The Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Danish Singh
- The Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Lance Wells
- The Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Kelley W. Moremen
- The Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - William N. Lanzilotta
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
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10
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Ferent J, Zaidi D, Francis F. Extracellular Control of Radial Glia Proliferation and Scaffolding During Cortical Development and Pathology. Front Cell Dev Biol 2020; 8:578341. [PMID: 33178693 PMCID: PMC7596222 DOI: 10.3389/fcell.2020.578341] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 09/08/2020] [Indexed: 01/14/2023] Open
Abstract
During the development of the cortex, newly generated neurons migrate long-distances in the expanding tissue to reach their final positions. Pyramidal neurons are produced from dorsal progenitors, e.g., radial glia (RGs) in the ventricular zone, and then migrate along RG processes basally toward the cortex. These neurons are hence dependent upon RG extensions to support their migration from apical to basal regions. Several studies have investigated how intracellular determinants are required for RG polarity and subsequent formation and maintenance of their processes. Fewer studies have identified the influence of the extracellular environment on this architecture. This review will focus on extracellular factors which influence RG morphology and pyramidal neuronal migration during normal development and their perturbations in pathology. During cortical development, RGs are present in different strategic positions: apical RGs (aRGs) have their cell bodies located in the ventricular zone with an apical process contacting the ventricle, while they also have a basal process extending radially to reach the pial surface of the cortex. This particular conformation allows aRGs to be exposed to long range and short range signaling cues, whereas basal RGs (bRGs, also known as outer RGs, oRGs) have their cell bodies located throughout the cortical wall, limiting their access to ventricular factors. Long range signals impacting aRGs include secreted molecules present in the embryonic cerebrospinal fluid (e.g., Neuregulin, EGF, FGF, Wnt, BMP). Secreted molecules also contribute to the extracellular matrix (fibronectin, laminin, reelin). Classical short range factors include cell to cell signaling, adhesion molecules and mechano-transduction mechanisms (e.g., TAG1, Notch, cadherins, mechanical tension). Changes in one or several of these components influencing the RG extracellular environment can disrupt the development or maintenance of RG architecture on which neuronal migration relies, leading to a range of cortical malformations. First, we will detail the known long range signaling cues impacting RG. Then, we will review how short range cell contacts are also important to instruct the RG framework. Understanding how RG processes are structured by their environment to maintain and support radial migration is a critical part of the investigation of neurodevelopmental disorders.
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Affiliation(s)
- Julien Ferent
- Inserm, U 1270, Paris, France.,Sorbonne University, UMR-S 1270, IFM, Paris, France.,Institut du Fer á Moulin, Paris, France
| | - Donia Zaidi
- Inserm, U 1270, Paris, France.,Sorbonne University, UMR-S 1270, IFM, Paris, France.,Institut du Fer á Moulin, Paris, France
| | - Fiona Francis
- Inserm, U 1270, Paris, France.,Sorbonne University, UMR-S 1270, IFM, Paris, France.,Institut du Fer á Moulin, Paris, France
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11
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Furukawa T, Ueno A, Omori Y. Molecular mechanisms underlying selective synapse formation of vertebrate retinal photoreceptor cells. Cell Mol Life Sci 2020; 77:1251-1266. [PMID: 31586239 PMCID: PMC11105113 DOI: 10.1007/s00018-019-03324-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 09/21/2019] [Accepted: 09/25/2019] [Indexed: 11/29/2022]
Abstract
In vertebrate central nervous systems (CNSs), highly diverse neurons are selectively connected via synapses, which are essential for building an intricate neural network. The vertebrate retina is part of the CNS and is comprised of a distinct laminar organization, which serves as a good model system to study developmental synapse formation mechanisms. In the retina outer plexiform layer, rods and cones, two types of photoreceptor cells, elaborate selective synaptic contacts with ON- and/or OFF-bipolar cell terminals as well as with horizontal cell terminals. In the mouse retina, three photoreceptor subtypes and at least 15 bipolar subtypes exist. Previous and recent studies have significantly progressed our understanding of how selective synapse formation, between specific subtypes of photoreceptor and bipolar cells, is designed at the molecular level. In the ON pathway, photoreceptor-derived secreted and transmembrane proteins directly interact in trans with the GRM6 (mGluR6) complex, which is localized to ON-bipolar cell dendritic terminals, leading to selective synapse formation. Here, we review our current understanding of the key factors and mechanisms underlying selective synapse formation of photoreceptor cells with bipolar and horizontal cells in the retina. In addition, we describe how defects/mutations of the molecules involved in photoreceptor synapse formation are associated with human retinal diseases and visual disorders.
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Affiliation(s)
- Takahisa Furukawa
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Akiko Ueno
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yoshihiro Omori
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
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12
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Amin M, Elsayed L, Ahmed AE. Clinical and Genetic Characteristics of Leukodystrophies in Africa. J Neurosci Rural Pract 2019; 8:S89-S93. [PMID: 28936078 PMCID: PMC5602269 DOI: 10.4103/jnrp.jnrp_511_16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Recent understanding of the genetic basis of neurological disorders in Africa has grown rapidly in the last two decades. Africa harbors the largest genetic repertoire in the world which gives unique opportunity to discover novel variant, genes, and molecular pathways associated with various neurological diseases. Despite that, large-scale genomic and exome studies are severely lacking especially for neglected diseases such as leukodystrophies. This review aims to shed light on the currently developed research in leukodystrophies in Africa. We reviewed all research articles related to “Leukodystrophy in Africa” published in Medline/PubMed and Google Scholar databases up to date. We found very few studies in leukodystrophy from Africa, especially from the Sub-Saharan regions. Metachromatic leukodystrophy was the most studied type of leukodystrophy. Published studies from North Africa (Tunisia, Morocco, and Egypt) were very limited in either sample size (case studies or single/few family studies) or molecular methods (targeted sequencing or polymerase chain reaction-restriction fragment length polymorphisms). More studies (GWAS or large family studies) with advanced techniques such as exome or whole genome sequencing are needed to unveil the genetic basis of leukodystrophy in Africa. Unmasking novel genes and molecular pathways of leukodystrophies invariably lead to better detection and treatment for both Africans and worldwide populations.
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Affiliation(s)
- Mutaz Amin
- Department of Biochemistry, Faculty of Medicine, University of Khartoum, Khartoum, Sudan
| | - Liena Elsayed
- Department of Biochemistry, Faculty of Medicine, University of Khartoum, Khartoum, Sudan
| | - Ammar Eltahir Ahmed
- Department of Physiology, Faculty of Medicine, University of Khartoum, Khartoum, Sudan
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13
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Brancaccio A. A molecular overview of the primary dystroglycanopathies. J Cell Mol Med 2019; 23:3058-3062. [PMID: 30838779 PMCID: PMC6484290 DOI: 10.1111/jcmm.14218] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 01/22/2019] [Accepted: 01/23/2019] [Indexed: 01/17/2023] Open
Abstract
Dystroglycan is a major non-integrin adhesion complex that connects the cytoskeleton to the surrounding basement membranes, thus providing stability to skeletal muscle. In Vertebrates, hypoglycosylation of α-dystroglycan has been strongly linked to muscular dystrophy phenotypes, some of which also show variable degrees of cognitive impairments, collectively termed dystroglycanopathies. Only a small number of mutations in the dystroglycan gene, leading to the so called primary dystroglycanopathies, has been described so far, as opposed to the ever-growing number of identified secondary or tertiary dystroglycanopathies (caused by genetic abnormalities in glycosyltransferases or in enzymes involved in the synthesis of the carbohydrate building blocks). The few mutations found within the autonomous N-terminal domain of α-dystroglycan seem to destabilise it to different degrees, without influencing the overall folding and targeting of the dystroglycan complex. On the contrary other mutations, some located at the α/β interface of the dystroglycan complex, seem to be able to interfere with its maturation, thus compromising its stability and eventually leading to the intracellular engulfment and/or partial or even total degradation of the dystroglycan uncleaved precursor.
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Affiliation(s)
- Andrea Brancaccio
- School of Biochemistry, University of Bristol, Bristol, UK.,Istituto di Chimica del Riconoscimento Molecolare - CNR c/o Università Cattolica del Sacro Cuore, Roma, Italy
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14
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Nickolls AR, Bönnemann CG. The roles of dystroglycan in the nervous system: insights from animal models of muscular dystrophy. Dis Model Mech 2018; 11:11/12/dmm035931. [PMID: 30578246 PMCID: PMC6307911 DOI: 10.1242/dmm.035931] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Dystroglycan is a cell membrane protein that binds to the extracellular matrix in a variety of mammalian tissues. The α-subunit of dystroglycan (αDG) is heavily glycosylated, including a special O-mannosyl glycoepitope, relying upon this unique glycosylation to bind its matrix ligands. A distinct group of muscular dystrophies results from specific hypoglycosylation of αDG, and they are frequently associated with central nervous system involvement, ranging from profound brain malformation to intellectual disability without evident morphological defects. There is an expanding literature addressing the function of αDG in the nervous system, with recent reports demonstrating important roles in brain development and in the maintenance of neuronal synapses. Much of these data are derived from an increasingly rich array of experimental animal models. This Review aims to synthesize the information from such diverse models, formulating an up-to-date understanding about the various functions of αDG in neurons and glia of the central and peripheral nervous systems. Where possible, we integrate these data with our knowledge of the human disorders to promote translation from basic mechanistic findings to clinical therapies that take the neural phenotypes into account. Summary: Dystroglycan is a ubiquitous matrix receptor linked to brain and muscle disease. Unraveling the functions of this protein will inform basic and translational research on neural development and muscular dystrophies.
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Affiliation(s)
- Alec R Nickolls
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.,Department of Neuroscience, Brown University, Providence, RI 02912, USA
| | - Carsten G Bönnemann
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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15
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Dai Y, Liang S, Dong X, Zhao Y, Ren H, Guan Y, Yin H, Li C, Chen L, Cui L, Banerjee S. Whole exome sequencing identified a novel DAG1 mutation in a patient with rare, mild and late age of onset muscular dystrophy-dystroglycanopathy. J Cell Mol Med 2018; 23:811-818. [PMID: 30450679 PMCID: PMC6349151 DOI: 10.1111/jcmm.13979] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 10/02/2018] [Indexed: 11/27/2022] Open
Abstract
Muscular dystrophy‐dystroglycanopathy (limb‐girdle), type C, 9 (MDDGC9) is the rarest type of autosomal recessive muscular dystrophies. MDDGC9 is manifested with an early onset in childhood. Patients with MDDGC9 usually identified with defective glycosylation of DAG1, hence it is known as “dystroglycanopathies”. Here, we report a Chinese pedigree presented with mild MDDGC9. The proband is a 64 years old Chinese man. In this family, both the proband and proband's younger brother have been suffering from mild and late onset MDDGC9. Muscle biopsy showed that the left deltoid muscle with an advanced stage of dystrophic change. Immunohistochemistry staining of dystrophin, α‐sarcoglycan, β‐sarcoglycan and dysferlin are normal. Molecular genetic analysis of the proband has been done with whole exome sequencing. A homozygous novel missense mutation (c.2326C>T; p.R776C) in the exon 3 of the DAG1 gene has been identified in the proband. Sanger sequencing revealed that this missense mutation is co‐segregated well among the affected and unaffected (carrier) family members. This mutation is not detected in 200 normal healthy control individuals. This novel homozygous missense mutation (c.2326C>T) causes substitution of arginine by cystine at the position of 776 (p.R776C) which is evolutionarily highly conserved. Immunoblotting studies revealed that a significant reduction of α‐dystroglycan expression in the muscle tissue. The novelty of our study is that it is a first report of DAG1 associated muscular dystrophy‐dystroglycanopathy (limb‐girdle), type C, 9 (MDDGC9) with mild and late age of onset. In Chinese population this is the first report of DAG1 associated MDDGC9.
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Affiliation(s)
- Yi Dai
- Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
| | - Shengran Liang
- School of Life Science and Biopharmaceuticals, Guangdong Pharmaceutical University, Guangzhou, China
| | - Xue Dong
- Department of Cell Biology, Tianjin Medical University, Tianjin, China
| | - Yanhuan Zhao
- Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
| | - Haitao Ren
- Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
| | - Yuzhou Guan
- Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
| | - Haifang Yin
- Department of Cell Biology, Tianjin Medical University, Tianjin, China
| | - Chen Li
- Department of Cell Biology and Medical Genetics, School of Medicine, Zhejiang University, Hangzhou, China
| | - Lin Chen
- Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
| | - Liying Cui
- Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China.,Neurosciences Center, Chinese Academy of Medical Sciences, Beijing, China
| | - Santasree Banerjee
- Department of Cell Biology and Medical Genetics, School of Medicine, Zhejiang University, Hangzhou, China
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16
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Detection of variants in dystroglycanopathy-associated genes through the application of targeted whole-exome sequencing analysis to a large cohort of patients with unexplained limb-girdle muscle weakness. Skelet Muscle 2018; 8:23. [PMID: 30060766 PMCID: PMC6066920 DOI: 10.1186/s13395-018-0170-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 07/13/2018] [Indexed: 12/16/2022] Open
Abstract
Background Dystroglycanopathies are a clinically and genetically heterogeneous group of disorders that are typically characterised by limb-girdle muscle weakness. Mutations in 18 different genes have been associated with dystroglycanopathies, the encoded proteins of which typically modulate the binding of α-dystroglycan to extracellular matrix ligands by altering its glycosylation. This results in a disruption of the structural integrity of the myocyte, ultimately leading to muscle degeneration. Methods Deep phenotypic information was gathered using the PhenoTips online software for 1001 patients with unexplained limb-girdle muscle weakness from 43 different centres across 21 European and Middle Eastern countries. Whole-exome sequencing with at least 250 ng DNA was completed using an Illumina exome capture and a 38 Mb baited target. Genes known to be associated with dystroglycanopathies were analysed for disease-causing variants. Results Suspected pathogenic variants were detected in DPM3, ISPD, POMT1 and FKTN in one patient each, in POMK in two patients, in GMPPB in three patients, in FKRP in eight patients and in POMT2 in ten patients. This indicated a frequency of 2.7% for the disease group within the cohort of 1001 patients with unexplained limb-girdle muscle weakness. The phenotypes of the 27 patients were highly variable, yet with a fundamental presentation of proximal muscle weakness and elevated serum creatine kinase. Conclusions Overall, we have identified 27 patients with suspected pathogenic variants in dystroglycanopathy-associated genes. We present evidence for the genetic and phenotypic diversity of the dystroglycanopathies as a disease group, while also highlighting the advantage of incorporating next-generation sequencing into the diagnostic pathway of rare diseases. Electronic supplementary material The online version of this article (10.1186/s13395-018-0170-1) contains supplementary material, which is available to authorized users.
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17
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Sarkozy A, Torelli S, Mein R, Henderson M, Phadke R, Feng L, Sewry C, Ala P, Yau M, Bertoli M, Willis T, Hammans S, Manzur A, Sframeli M, Norwood F, Rakowicz W, Radunovic A, Vaidya SS, Parton M, Walker M, Marino S, Offiah C, Farrugia ME, Mamutse G, Marini-Bettolo C, Wraige E, Beeson D, Lochmüller H, Straub V, Bushby K, Barresi R, Muntoni F. Mobility shift of beta-dystroglycan as a marker of GMPPB gene-related muscular dystrophy. J Neurol Neurosurg Psychiatry 2018; 89:762-768. [PMID: 29437916 DOI: 10.1136/jnnp-2017-316956] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 12/20/2017] [Accepted: 01/03/2018] [Indexed: 12/13/2022]
Abstract
BACKGROUND Defects in glycosylation of alpha-dystroglycan (α-DG) cause autosomal-recessive disorders with wide clinical and genetic heterogeneity, with phenotypes ranging from congenital muscular dystrophies to milder limb girdle muscular dystrophies. Patients show variable reduction of immunoreactivity to antibodies specific for glycoepitopes of α-DG on a muscle biopsy. Recessive mutations in 18 genes, including guanosine diphosphate mannose pyrophosphorylase B (GMPPB), have been reported to date. With no specific clinical and pathological handles, diagnosis requires parallel or sequential analysis of all known genes. METHODS We describe clinical, genetic and biochemical findings of 21 patients with GMPPB-associated dystroglycanopathy. RESULTS We report eight novel mutations and further expand current knowledge on clinical and muscle MRI features of this condition. In addition, we report a consistent shift in the mobility of beta-dystroglycan (β-DG) on Western blot analysis of all patients analysed by this mean. This was only observed in patients with GMPPB in our large dystroglycanopathy cohort. We further demonstrate that this mobility shift in patients with GMPPB was due to abnormal N-linked glycosylation of β-DG. CONCLUSIONS Our data demonstrate that a change in β-DG electrophoretic mobility in patients with dystroglycanopathy is a distinctive marker of the molecular defect in GMPPB.
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Affiliation(s)
- Anna Sarkozy
- Dubowitz Neuromuscular Centre, MRC Centre for Neuromuscular Diseases, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Silvia Torelli
- Dubowitz Neuromuscular Centre, MRC Centre for Neuromuscular Diseases, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Rachael Mein
- DNA Laboratory, Viapath, Guy's Hospital, London, UK
| | - Matt Henderson
- Rare Diseases Advisory Group Service for Neuromuscular Diseases, Muscle Immunoanalysis Unit, Dental Hospital, Newcastle upon Tyne, UK
| | - Rahul Phadke
- Dubowitz Neuromuscular Centre, MRC Centre for Neuromuscular Diseases, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Lucy Feng
- Dubowitz Neuromuscular Centre, MRC Centre for Neuromuscular Diseases, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Caroline Sewry
- Dubowitz Neuromuscular Centre, MRC Centre for Neuromuscular Diseases, UCL Great Ormond Street Institute of Child Health, London, UK.,The Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, UK
| | - Pierpaolo Ala
- Dubowitz Neuromuscular Centre, MRC Centre for Neuromuscular Diseases, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Michael Yau
- DNA Laboratory, Viapath, Guy's Hospital, London, UK
| | - Marta Bertoli
- The John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases Institute of Genetic Medicine, University of Newcastle, Newcastle upon Tyne, UK.,Northern Genetics Service, Newcastle upon Tyne NHS Trust, Newcastle upon Tyne, UK
| | - Tracey Willis
- The Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, UK
| | - Simon Hammans
- Wessex Neurological Centre, University Hospital of Southampton, Southampton, UK
| | - Adnan Manzur
- Dubowitz Neuromuscular Centre, MRC Centre for Neuromuscular Diseases, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Maria Sframeli
- Dubowitz Neuromuscular Centre, MRC Centre for Neuromuscular Diseases, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Fiona Norwood
- Department of Neurology, King's College Hospital, London, UK
| | - Wojtek Rakowicz
- Department of Neurology, Hampshire Hospitals NHS Foundation Trust, Royal Hampshire County Hospital, Winchester, UK
| | | | | | - Matt Parton
- MRC Centre for Neuromuscular Diseases, Institute of Neurology, University College London, London, UK
| | - Mark Walker
- Department of Cellular Pathology, Southampton University Hospitals, Southampton, UK
| | - Silvia Marino
- Queen Mary University of London, Barts and the London School of Medicine and Dentistry, London, UK
| | - Curtis Offiah
- Department of Radiology, Royal London Hospital, London, UK
| | - Maria Elena Farrugia
- Department of Neurology, Institute of Neurological Sciences, Southern General Hospital, Glasgow, UK
| | - Godwin Mamutse
- Department of Neurology, Norfolk and Norwich University Hospital, Norwich, UK
| | - Chiara Marini-Bettolo
- The John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases Institute of Genetic Medicine, University of Newcastle, Newcastle upon Tyne, UK
| | - Elizabeth Wraige
- Department of Paediatric Neurology, Neuromuscular Service, Evelina Children's Hospital, St Thomas' Hospital, London, UK
| | - David Beeson
- Neuromuscular Disorders Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, Oxford, UK
| | - Hanns Lochmüller
- The John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases Institute of Genetic Medicine, University of Newcastle, Newcastle upon Tyne, UK
| | - Volker Straub
- The John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases Institute of Genetic Medicine, University of Newcastle, Newcastle upon Tyne, UK
| | - Kate Bushby
- The John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases Institute of Genetic Medicine, University of Newcastle, Newcastle upon Tyne, UK
| | - Rita Barresi
- Rare Diseases Advisory Group Service for Neuromuscular Diseases, Muscle Immunoanalysis Unit, Dental Hospital, Newcastle upon Tyne, UK.,The John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases Institute of Genetic Medicine, University of Newcastle, Newcastle upon Tyne, UK
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, MRC Centre for Neuromuscular Diseases, UCL Great Ormond Street Institute of Child Health, London, UK
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18
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Leibovitz Z, Mandel H, Falik-Zaccai TC, Ben Harouch S, Savitzki D, Krajden-Haratz K, Gindes L, Tamarkin M, Lev D, Dobyns WB, Lerman-Sagie T. Walker-Warburg syndrome and tectocerebellar dysraphia: A novel association caused by a homozygous DAG1 mutation. Eur J Paediatr Neurol 2018; 22:525-531. [PMID: 29337005 DOI: 10.1016/j.ejpn.2017.12.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 11/25/2017] [Accepted: 12/18/2017] [Indexed: 01/09/2023]
Abstract
OBJECTIVES To elaborate the imaging phenotype associated with a homozygous c.743C > del frameshift mutation in DAG1 leading to complete absence of both α- and β-dystroglycan previously reported in a consanguineous Israeli-Arab family. METHODS We analyzed prenatal and postnatal imaging data of patients from a consanguineous Israeli-Arab kindred harboring the DAG1 mutation. RESULTS The imaging studies (fetal ultrasound, CT scan and postnatal MRI) demonstrated: flat cortex (abnormally thick with irregular pebbled cortical-white matter border on MRI), hydrocephalus, scattered small periventricular heterotopia and subependymal hemorrhages and calcifications, z-shaped brainstem, and in addition an occipital encephalocele, vermian agenesis, and an elongated and thick tectum (tectocerebellar dysraphia). CONCLUSIONS The novel association of cobblestone malformation with tectocerebellar dysraphia as part of WWS is characteristic of the homozygous c.743C > del frameshift mutation in the DAG1 gene.
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Affiliation(s)
- Zvi Leibovitz
- Obstetrics-Gynecology Ultrasound Unit, Bnai-Zion Medical Center and Rappoport Faculty of Medicine, The Technion, Haifa, Israel; Fetal Neurology Clinic, Obstetrics-Gynecology Ultrasound Unit, Department of Obstetrics and Gynecology, Wolfson Medical Center, Holon and Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
| | - Hanna Mandel
- Institute of Human Genetics and Metabolic Disorders, Western Galilee Medical Center, Naharia and Faculty of Medicine in the Galilee, Bar Ilan University, Safed, Israel
| | - Tzipora C Falik-Zaccai
- Institute of Human Genetics and Metabolic Disorders, Western Galilee Medical Center, Naharia and Faculty of Medicine in the Galilee, Bar Ilan University, Safed, Israel
| | - Shani Ben Harouch
- Institute of Human Genetics and Metabolic Disorders, Western Galilee Medical Center, Naharia and Faculty of Medicine in the Galilee, Bar Ilan University, Safed, Israel
| | - David Savitzki
- Pediatric Neurology and Development Unit, Western Galilee Medical Center, Naharia and Faculty of Medicine in the Galilee, Bar Ilan University, Safed, Israel
| | - Karina Krajden-Haratz
- Fetal Neurology Clinic, Obstetrics-Gynecology Ultrasound Unit, Department of Obstetrics and Gynecology, Wolfson Medical Center, Holon and Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Liat Gindes
- Fetal Neurology Clinic, Obstetrics-Gynecology Ultrasound Unit, Department of Obstetrics and Gynecology, Wolfson Medical Center, Holon and Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Mordechai Tamarkin
- Fetal Neurology Clinic, Obstetrics-Gynecology Ultrasound Unit, Department of Obstetrics and Gynecology, Wolfson Medical Center, Holon and Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Dorit Lev
- Fetal Neurology Clinic, Obstetrics-Gynecology Ultrasound Unit, Department of Obstetrics and Gynecology, Wolfson Medical Center, Holon and Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel; The Rina Mor Institute of Medical Genetics, Wolfson Medical Center, Holon and Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - William B Dobyns
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Tally Lerman-Sagie
- Fetal Neurology Clinic, Obstetrics-Gynecology Ultrasound Unit, Department of Obstetrics and Gynecology, Wolfson Medical Center, Holon and Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel; Pediatric Neurology Unit, Wolfson Medical Center, Holon and Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
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19
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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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Adle-Biassette H, Golden JA, Harding B. Developmental and perinatal brain diseases. HANDBOOK OF CLINICAL NEUROLOGY 2018; 145:51-78. [PMID: 28987191 DOI: 10.1016/b978-0-12-802395-2.00006-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
This chapter briefly describes the normal development of the nervous system, the neuropathology and pathophysiology of acquired and secondary disorders affecting the embryo, fetus, and child. They include CNS manifestations of chromosomal change; forebrain patterning defects; disorders of the brain size; cell migration and specification disorders; cerebellum, hindbrain and spinal patterning defects; hydrocephalus; secondary malformations and destructive pathologies; vascular malformations; arachnoid cysts and infectious diseases. The distinction between malformations and disruptions is important for pathogenesis and genetic counseling.
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Affiliation(s)
- Homa Adle-Biassette
- Department of Pathology, Lariboisière Hospital, APHP and Paris Diderot University, Sorbonne Paris Cité, Paris, France.
| | - Jeffery A Golden
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Brian Harding
- Department of Pathology/Neuropathology, Children's Hospital of Philadelphia, Philadelphia, PA, United States
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Maroofian R, Riemersma M, Jae LT, Zhianabed N, Willemsen MH, Wissink-Lindhout WM, Willemsen MA, de Brouwer APM, Mehrjardi MYV, Ashrafi MR, Kusters B, Kleefstra T, Jamshidi Y, Nasseri M, Pfundt R, Brummelkamp TR, Abbaszadegan MR, Lefeber DJ, van Bokhoven H. B3GALNT2 mutations associated with non-syndromic autosomal recessive intellectual disability reveal a lack of genotype-phenotype associations in the muscular dystrophy-dystroglycanopathies. Genome Med 2017; 9:118. [PMID: 29273094 PMCID: PMC5740572 DOI: 10.1186/s13073-017-0505-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Accepted: 12/05/2017] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND The phenotypic severity of congenital muscular dystrophy-dystroglycanopathy (MDDG) syndromes associated with aberrant glycosylation of α-dystroglycan ranges from the severe Walker-Warburg syndrome or muscle-eye-brain disease to mild, late-onset, isolated limb-girdle muscular dystrophy without neural involvement. However, muscular dystrophy is invariably found across the spectrum of MDDG patients. METHODS Using linkage mapping and whole-exome sequencing in two families with an unexplained neurodevelopmental disorder, we have identified homozygous and compound heterozygous mutations in B3GALNT2. RESULTS The first family comprises two brothers of Dutch non-consanguineous parents presenting with mild ID and behavioral problems. Immunohistochemical analysis of muscle biopsy revealed no significant aberrations, in line with the absence of a muscular phenotype in the affected siblings. The second family includes five affected individuals from an Iranian consanguineous kindred with mild-to-moderate intellectual disability (ID) and epilepsy without any notable neuroimaging, muscle, or eye abnormalities. Complementation assays of the compound heterozygous mutations identified in the two brothers had a comparable effect on the O-glycosylation of α-dystroglycan as previously reported mutations that are associated with severe muscular phenotypes. CONCLUSIONS In conclusion, we show that mutations in B3GALNT2 can give rise to a novel MDDG syndrome presentation, characterized by ID associated variably with seizure, but without any apparent muscular involvement. Importantly, B3GALNT2 activity does not fully correlate with the severity of the phenotype as assessed by the complementation assay.
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Affiliation(s)
- Reza Maroofian
- Genetics and Molecular Cell Sciences Research Centre, St George's University of London, Cranmer Terrace, London, SW17 0RE, UK
| | - Moniek Riemersma
- Department of Neurology, Radboud university medical center, Geert Grooteplein 10, 6525 GA, Nijmegen, The Netherlands
- Department of Laboratory Medicine, Radboud university medical center, Geert Grooteplein 10, 6525 GA, Nijmegen, The Netherlands
- Department of Human Genetics 855, Donders Institute for Brain, Cognition and Behaviour, Radboud university medical center, Geert Grooteplein 10, 6525 GA, Nijmegen, The Netherlands
| | - Lucas T Jae
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Straße 25, 81377, Munich, Germany
| | | | - Marjolein H Willemsen
- Department of Human Genetics 855, Donders Institute for Brain, Cognition and Behaviour, Radboud university medical center, Geert Grooteplein 10, 6525 GA, Nijmegen, The Netherlands
| | - Willemijn M Wissink-Lindhout
- Department of Human Genetics 855, Donders Institute for Brain, Cognition and Behaviour, Radboud university medical center, Geert Grooteplein 10, 6525 GA, Nijmegen, The Netherlands
| | - Michèl A Willemsen
- Department of Neurology, Radboud university medical center, Geert Grooteplein 10, 6525 GA, Nijmegen, The Netherlands
| | - Arjan P M de Brouwer
- Department of Human Genetics 855, Donders Institute for Brain, Cognition and Behaviour, Radboud university medical center, Geert Grooteplein 10, 6525 GA, Nijmegen, The Netherlands
| | | | - Mahmoud Reza Ashrafi
- Department of Child Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Benno Kusters
- Department of Pathology, Radboud university medical center, Geert Grooteplein 10, 6525 GA, Nijmegen, The Netherlands
- Department of Pathology, Maastricht University Medical Centre, 6229 HX, Maastricht, The Netherlands
| | - Tjitske Kleefstra
- Department of Human Genetics 855, Donders Institute for Brain, Cognition and Behaviour, Radboud university medical center, Geert Grooteplein 10, 6525 GA, Nijmegen, The Netherlands
| | - Yalda Jamshidi
- Genetics and Molecular Cell Sciences Research Centre, St George's University of London, Cranmer Terrace, London, SW17 0RE, UK
| | - Mojila Nasseri
- Pardis Clinical and Genetics Laboratory, Mashhad, Iran
- Medical Genetics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Rolph Pfundt
- Department of Human Genetics 855, Donders Institute for Brain, Cognition and Behaviour, Radboud university medical center, Geert Grooteplein 10, 6525 GA, Nijmegen, The Netherlands
| | - Thijn R Brummelkamp
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Straße 25, 81377, Munich, Germany
| | - Mohammad Reza Abbaszadegan
- Pardis Clinical and Genetics Laboratory, Mashhad, Iran
- Division of Human Genetics, Immunology Research Center, Avicenna Research Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Dirk J Lefeber
- Department of Neurology, Radboud university medical center, Geert Grooteplein 10, 6525 GA, Nijmegen, The Netherlands
- Department of Laboratory Medicine, Radboud university medical center, Geert Grooteplein 10, 6525 GA, Nijmegen, The Netherlands
| | - Hans van Bokhoven
- Department of Human Genetics 855, Donders Institute for Brain, Cognition and Behaviour, Radboud university medical center, Geert Grooteplein 10, 6525 GA, Nijmegen, The Netherlands.
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22
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Signorino G, Covaceuszach S, Bozzi M, Hübner W, Mönkemöller V, Konarev PV, Cassetta A, Brancaccio A, Sciandra F. A dystroglycan mutation (p.Cys667Phe) associated to muscle-eye-brain disease with multicystic leucodystrophy results in ER-retention of the mutant protein. Hum Mutat 2017; 39:266-280. [PMID: 29134705 DOI: 10.1002/humu.23370] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 10/13/2017] [Accepted: 11/06/2017] [Indexed: 01/11/2023]
Abstract
Dystroglycan (DG) is a cell adhesion complex composed by two subunits, the highly glycosylated α-DG and the transmembrane β-DG. In skeletal muscle, DG is involved in dystroglycanopathies, a group of heterogeneous muscular dystrophies characterized by a reduced glycosylation of α-DG. The genes mutated in secondary dystroglycanopathies are involved in the synthesis of O-mannosyl glycans and in the O-mannosylation pathway of α-DG. Mutations in the DG gene (DAG1), causing primary dystroglycanopathies, destabilize the α-DG core protein influencing its binding to modifying enzymes. Recently, a homozygous mutation (p.Cys699Phe) hitting the β-DG ectodomain has been identified in a patient affected by muscle-eye-brain disease with multicystic leucodystrophy, suggesting that other mechanisms than hypoglycosylation of α-DG could be implicated in dystroglycanopathies. Herein, we have characterized the DG murine mutant counterpart by transfection in cellular systems and high-resolution microscopy. We observed that the mutation alters the DG processing leading to retention of its uncleaved precursor in the endoplasmic reticulum. Accordingly, small-angle X-ray scattering data, corroborated by biochemical and biophysical experiments, revealed that the mutation provokes an alteration in the β-DG ectodomain overall folding, resulting in disulfide-associated oligomerization. Our data provide the first evidence of a novel intracellular mechanism, featuring an anomalous endoplasmic reticulum-retention, underlying dystroglycanopathy.
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Affiliation(s)
- Giulia Signorino
- Istituto di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Roma, Italy
| | | | - Manuela Bozzi
- Istituto di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Roma, Italy.,Istituto di Chimica del Riconoscimento Molecolare - CNR c/o Istituto di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Roma, Italy
| | - Wolfgang Hübner
- Biomolecular Photonics, University of Bielefeld, Bielefeld, Germany
| | | | - Petr V Konarev
- A.V. Shubnikov Institute of Crystallography of Federal Scientific Research Centre "Crystallography and Photonics" of Russian Academy of Sciences, Leninsky prospect 59, Moscow, Russia
| | - Alberto Cassetta
- Istituto di Cristallografia - CNR, Trieste Outstation, Trieste, Italy
| | - Andrea Brancaccio
- Istituto di Chimica del Riconoscimento Molecolare - CNR c/o Istituto di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Roma, Italy.,School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Francesca Sciandra
- Istituto di Chimica del Riconoscimento Molecolare - CNR c/o Istituto di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Roma, Italy
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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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24
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Sheikh MO, Halmo SM, Wells L. Recent advancements in understanding mammalian O-mannosylation. Glycobiology 2017; 27:806-819. [PMID: 28810660 PMCID: PMC6082599 DOI: 10.1093/glycob/cwx062] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 06/25/2017] [Accepted: 06/28/2017] [Indexed: 02/07/2023] Open
Abstract
The post-translational glycosylation of select proteins by O-linked mannose (O-mannose or O-man) is a conserved modification from yeast to humans and has been shown to be necessary for proper development and growth. The most well studied O-mannosylated mammalian protein is α-dystroglycan (α-DG). Hypoglycosylation of α-DG results in varying severities of congenital muscular dystrophies, cancer progression and metastasis, and inhibited entry and infection of certain arenaviruses. Defects in the gene products responsible for post-translational modification of α-DG, primarily glycosyltransferases, are the basis for these diseases. The multitude of clinical phenotypes resulting from defective O-mannosylation highlights the biomedical significance of this unique modification. Elucidation of the various O-mannose biosynthetic pathways is imperative to understanding a broad range of human diseases and for the development of novel therapeutics. In this review, we will focus on recent discoveries delineating the various enzymes, structures and functions associated with O-mannose-initiated glycoproteins. Additionally, we discuss current gaps in our knowledge of mammalian O-mannosylation, discuss the evolution of this pathway, and illustrate the utility and limitations of model systems to study functions of O-mannosylation.
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Affiliation(s)
- M Osman Sheikh
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
| | - Stephanie M Halmo
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
- Department of Biochemistry and Molecular Biology, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
| | - Lance Wells
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
- Department of Biochemistry and Molecular Biology, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
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25
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Fukai Y, Ohsawa Y, Ohtsubo H, Nishimatsu SI, Hagiwara H, Noda M, Sasaoka T, Murakami T, Sunada Y. Cleavage of β-dystroglycan occurs in sarcoglycan-deficient skeletal muscle without MMP-2 and MMP-9. Biochem Biophys Res Commun 2017; 492:199-205. [PMID: 28821434 DOI: 10.1016/j.bbrc.2017.08.048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 08/13/2017] [Indexed: 10/19/2022]
Abstract
BACKGROUND The dystroglycan complex consists of two subunits: extracellular α-dystroglycan and membrane-spanning β-dystroglycan, which provide a tight link between the extracellular matrix and the intracellular cytoskeleton. Previous studies showed that 43 kDa β-dystroglycan is proteolytically cleaved into the 30 kDa fragment by matrix metalloproteinases (MMPs) in various non-muscle tissues, whereas it is protected from cleavage in muscles by the sarcoglycan complex which resides close to the dystroglycan complex. It is noteworthy that cleaved β-dystroglycan is detected in muscles from patients with sarcoglycanopathy, sarcoglycan-deficient muscular dystrophy. In vitro assays using protease inhibitors suggest that both MMP-2 and MMP-9 contribute to the cleavage of β-dystroglycan. However, this has remained uninvestigated in vivo. METHODS We generated triple-knockout (TKO) mice targeting MMP-2, MMP-9 and γ-sarcoglycan to examine the status of β-dystroglycan cleavage in the absence of the candidate matrix metalloproteinases in sarcoglycan-deficient muscles. RESULTS Unexpectedly, β-dystroglycan was cleaved in muscles from TKO mice. Muscle pathology was not ameliorated but worsened in TKO mice compared with γ-sarcoglycan single-knockout mice. The gene expression of MMP-14 was up-regulated in TKO mice as well as in γ-sarcoglycan knockout mice. In vitro assay showed MMP-14 is capable to cleave β-dystroglycan. CONCLUSIONS Double-targeting of MMP-2 and MMP-9 cannot prevent cleavage of β-dystroglycan in sarcoglycanopathy. Thus, matrix metalloproteinases contributing to β-dystroglycan cleavage are redundant, and MMP-14 could participate in the pathogenesis of sarcoglycanopathy.
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Affiliation(s)
- Yuta Fukai
- Department of Neurology, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192, Japan
| | - Yutaka Ohsawa
- Department of Neurology, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192, Japan
| | - Hideaki Ohtsubo
- Department of Neurology, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192, Japan
| | - Shin-Ichiro Nishimatsu
- Department of Natural Science, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192, Japan
| | - Hiroki Hagiwara
- Department of Medical Science, Teikyo University of Science, 2-2-1 Senjusakuragi, Adachi-ku, Tokyo 120-0045, Japan
| | - Makoto Noda
- Department of Molecular Oncology, Kyoto University Graduate School of Medicine, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Toshikuni Sasaoka
- National Institute for Basic Biology, Okazaki 444-8585, Japan; Department of Laboratory Animal Science, Kitasato University School of Medicine, Sagamihara 252-0374, Japan; Department of Comparative and Experimental Medicine, Center for Bioresource-based Researches, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Tatsufumi Murakami
- Department of Neurology, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192, Japan
| | - Yoshihide Sunada
- Department of Neurology, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192, Japan.
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Covaceuszach S, Bozzi M, Bigotti MG, Sciandra F, Konarev PV, Brancaccio A, Cassetta A. Structural flexibility of human α-dystroglycan. FEBS Open Bio 2017; 7:1064-1077. [PMID: 28781947 PMCID: PMC5537065 DOI: 10.1002/2211-5463.12259] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 06/09/2017] [Indexed: 01/13/2023] Open
Abstract
Dystroglycan (DG), composed of α and β subunits, belongs to the dystrophin-associated glycoprotein complex. α-DG is an extracellular matrix protein that undergoes a complex post-translational glycosylation process. The bifunctional glycosyltransferase like-acetylglucosaminyltransferase (LARGE) plays a crucial role in the maturation of α-DG, enabling its binding to laminin. We have already structurally analyzed the N-terminal region of murine α-DG (α-DG-Nt) and of a pathological single point mutant that may affect recognition of LARGE, although the structural features of the potential interaction between LARGE and DG remain elusive. We now report on the crystal structure of the wild-type human α-DG-Nt that has allowed us to assess the reliability of our murine crystallographic structure as a α-DG-Nt general model. Moreover, we address for the first time both structures in solution. Interestingly, small-angle X-ray scattering (SAXS) reveals the existence of two main protein conformations ensembles. The predominant species is reminiscent of the crystal structure, while the less populated one assumes a more extended fold. A comparative analysis of the human and murine α-DG-Nt solution structures reveals that the two proteins share a common interdomain flexibility and population distribution of the two conformers. This is confirmed by the very similar stability displayed by the two orthologs as assessed by biochemical and biophysical experiments. These results highlight the need to take into account the molecular plasticity of α-DG-Nt in solution, as it can play an important role in the functional interactions with other binding partners.
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Affiliation(s)
| | - Manuela Bozzi
- Istituto di Biochimica e Biochimica ClinicaUniversità Cattolica del Sacro CuoreRomaItaly
- Istituto di Chimica del Riconoscimento MolecolareCNR c/o Università Cattolica del Sacro CuoreRomaItaly
| | | | - Francesca Sciandra
- Istituto di Chimica del Riconoscimento MolecolareCNR c/o Università Cattolica del Sacro CuoreRomaItaly
| | - Petr Valeryevich Konarev
- Shubnikov Institute of Crystallography of Federal Scientific Research Centre“Crystallography and Photonics” of Russian Academy of SciencesMoscowRussia
- National Research Centre “Kurchatov Institute”MoscowRussia
| | - Andrea Brancaccio
- Istituto di Chimica del Riconoscimento MolecolareCNR c/o Università Cattolica del Sacro CuoreRomaItaly
- School of BiochemistryUniversity of BristolUK
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Structural divergence of essential triad ribbon synapse proteins among placental mammals - Implications for preclinical trials in photoreceptor transplantation therapy. Exp Eye Res 2017; 159:156-167. [PMID: 28322827 DOI: 10.1016/j.exer.2017.03.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 01/24/2017] [Accepted: 03/17/2017] [Indexed: 11/22/2022]
Abstract
As photoreceptor transplantation rapidly moves closer to the clinic, verifying graft efficacy in animal models may have unforeseen xenogeneic barriers. Although photoreceptor transplants have most convincingly exhibited functional synaptogenesis in conspecific studies, such evidence (while ruling out false-positives due to: viral graft labeling, fusion/cytosolic transfer, or neuroprotection) has not yet been shown for discordant xenografts. From this, a fundamental question should be raised: is useful xenosynaptogenesis likely between human photoreceptors and mouse retina? The triad ribbon synapse (TRS) that would normally form is unique and contains trans-synaptic proteins essential to its formation and function. Thus, could interspecific structural divergence be present that may inhibit this trans-synaptic bridge in discordant xenografts? In an effort to address this question computationally, we compared eight recently confirmed (including subcellular location) TRS specific (or predominantly expressed at the TRS) proteins among placental mammals (1-to-1 orthologs) using HyPhy selection analysis (a predictive measure of structural divergence) and by using Phyre2 tertiary structural modeling. Here, selection analysis revealed strong positive (diversifying) selection acting on a particularly important TRS protein: pikachurin. This positive selection was localized to its second Laminin-G (LG)-like domain and on its N-terminal domain - a putative region of trans-synaptic interaction. Localization of structural divergence to the N-terminus of each putative post-translational cleavage (PTC) product may suggest neofunctionalization from ancestral uncleaved pikachurin - this would be consistent with a recent counter-paradigm report of pikachurin cleavage predominating at the TRS. From this, we suggest a dual role after cleavage where the N-terminal fragment can still mediate the trans-synaptic bridge, while the C-terminal fragment may act as a diffusible trophic or "homing" factor for bipolar cell dendrite migration. Tertiary structural models mirrored the conformational divergence predicted by selection analysis. With human and mouse pikachurin (as well as other TRS proteins) likely to diverge considerably in structure among placental mammals - alongside known inter-mammalian variation in TRS phenotype and protein repertoire, high levels of diversifying selection acting on genes involving sensation, considerable timespans allowing for genetic drift that can create xenogeneic epistasis, and uncertainty surrounding the extent of xenosynaptogenesis in PPC transplant studies to date - use of distantly related hosts to test human photoreceptor graft therapeutic efficacy should be considered with caution.
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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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Role of dystroglycan in limiting contraction-induced injury to the sarcomeric cytoskeleton of mature skeletal muscle. Proc Natl Acad Sci U S A 2016; 113:10992-7. [PMID: 27625424 DOI: 10.1073/pnas.1605265113] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Dystroglycan (DG) is a highly expressed extracellular matrix receptor that is linked to the cytoskeleton in skeletal muscle. DG is critical for the function of skeletal muscle, and muscle with primary defects in the expression and/or function of DG throughout development has many pathological features and a severe muscular dystrophy phenotype. In addition, reduction in DG at the sarcolemma is a common feature in muscle biopsies from patients with various types of muscular dystrophy. However, the consequence of disrupting DG in mature muscle is not known. Here, we investigated muscles of transgenic mice several months after genetic knockdown of DG at maturity. In our study, an increase in susceptibility to contraction-induced injury was the first pathological feature observed after the levels of DG at the sarcolemma were reduced. The contraction-induced injury was not accompanied by increased necrosis, excitation-contraction uncoupling, or fragility of the sarcolemma. Rather, disruption of the sarcomeric cytoskeleton was evident as reduced passive tension and decreased titin immunostaining. These results reveal a role for DG in maintaining the stability of the sarcomeric cytoskeleton during contraction and provide mechanistic insight into the cause of the reduction in strength that occurs in muscular dystrophy after lengthening contractions.
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Mechanistic aspects of the formation of α-dystroglycan and therapeutic research for the treatment of α-dystroglycanopathy: A review. Mol Aspects Med 2016; 51:115-24. [PMID: 27421908 DOI: 10.1016/j.mam.2016.07.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Revised: 07/07/2016] [Accepted: 07/08/2016] [Indexed: 02/08/2023]
Abstract
α-Dystroglycanopathy, an autosomal recessive disease, is associated with the development of a variety of diseases, including muscular dystrophy. In humans, α-dystroglycanopathy includes various types of congenital muscular dystrophy such as Fukuyama type congenital muscular dystrophy (FCMD), muscle eye brain disease (MEB), and the Walker Warburg syndrome (WWS), and types of limb girdle muscular dystrophy 2I (LGMD2I). α-Dystroglycanopathy share a common etiology, since it is invariably caused by gene mutations that are associated with the O-mannose glycosylation pathway of α-dystroglycan (α-DG). α-DG is a central member of the dystrophin glycoprotein complex (DGC) family in peripheral membranes, and the proper glycosylation of α-DG is essential for it to bind to extracellular matrix proteins, such as laminin, to cell components. The disruption of this ligand-binding is thought to result in damage to cell membrane integration, leading to the development of muscular dystrophy. Clinical manifestations of α-dystroglycanopathy frequently include mild to severe alterations in the central nervous system and optical manifestations in addition to muscular dystrophy. Eighteen causative genes for α-dystroglycanopathy have been identified to date, and it is likely that more will be reported in the near future. These findings have stimulated extensive and energetic investigations in this research field, and novel glycosylation pathways have been implicated in the process. At the same time, the use of gene therapy, antisense therapy, and enzymatic supplementation have been evaluated as therapeutic possibilities for some types of α-dystroglycanopathy. Here we review the molecular and clinical findings associated with α-dystroglycanopathy and the development of therapeutic approaches, by comparing the approaches with the development of Duchenne muscular dystrophy.
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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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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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Human ISPD Is a Cytidyltransferase Required for Dystroglycan O-Mannosylation. ACTA ACUST UNITED AC 2015; 22:1643-52. [DOI: 10.1016/j.chembiol.2015.10.014] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 09/24/2015] [Accepted: 10/13/2015] [Indexed: 01/03/2023]
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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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Adams JC, Brancaccio A. The evolution of the dystroglycan complex, a major mediator of muscle integrity. Biol Open 2015; 4:1163-79. [PMID: 26319583 PMCID: PMC4582122 DOI: 10.1242/bio.012468] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Basement membrane (BM) extracellular matrices are crucial for the coordination of different tissue layers. A matrix adhesion receptor that is important for BM function and stability in many mammalian tissues is the dystroglycan (DG) complex. This comprises the non-covalently-associated extracellular α-DG, that interacts with laminin in the BM, and the transmembrane β-DG, that interacts principally with dystrophin to connect to the actin cytoskeleton. Mutations in dystrophin, DG, or several enzymes that glycosylate α-DG underlie severe forms of human muscular dystrophy. Nonwithstanding the pathophysiological importance of the DG complex and its fundamental interest as a non-integrin system of cell-ECM adhesion, the evolution of DG and its interacting proteins is not understood. We analysed the phylogenetic distribution of DG, its proximal binding partners and key processing enzymes in extant metazoan and relevant outgroups. We identify that DG originated after the divergence of ctenophores from porifera and eumetazoa. The C-terminal half of the DG core protein is highly-conserved, yet the N-terminal region, that includes the laminin-binding region, has undergone major lineage-specific divergences. Phylogenetic analysis based on the C-terminal IG2_MAT_NU region identified three distinct clades corresponding to deuterostomes, arthropods, and mollusks/early-diverging metazoans. Whereas the glycosyltransferases that modify α-DG are also present in choanoflagellates, the DG-binding proteins dystrophin and laminin originated at the base of the metazoa, and DG-associated sarcoglycan is restricted to cnidarians and bilaterians. These findings implicate extensive functional diversification of DG within invertebrate lineages and identify the laminin-DG-dystrophin axis as a conserved adhesion system that evolved subsequent to integrin-ECM adhesion, likely to enhance the functional complexity of cell-BM interactions in early metazoans.
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Affiliation(s)
- Josephine C Adams
- School of Biochemistry, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Andrea Brancaccio
- Istituto di Chimica del Riconoscimento Molecolare, CNR, Istituto di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, Roma 00168, Italy
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Genetic Engineering of Dystroglycan in Animal Models of Muscular Dystrophy. BIOMED RESEARCH INTERNATIONAL 2015; 2015:635792. [PMID: 26380289 PMCID: PMC4561298 DOI: 10.1155/2015/635792] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 03/11/2015] [Indexed: 01/24/2023]
Abstract
In skeletal muscle, dystroglycan (DG) is the central component of the dystrophin-glycoprotein complex (DGC), a multimeric protein complex that ensures a strong mechanical link between the extracellular matrix and the cytoskeleton. Several muscular dystrophies arise from mutations hitting most of the components of the DGC. Mutations within the DG gene (DAG1) have been recently associated with two forms of muscular dystrophy, one displaying a milder and one a more severe phenotype. This review focuses specifically on the animal (murine and others) model systems that have been developed with the aim of directly engineering DAG1 in order to study the DG function in skeletal muscle as well as in other tissues. In the last years, conditional animal models overcoming the embryonic lethality of the DG knock-out in mouse have been generated and helped clarifying the crucial role of DG in skeletal muscle, while an increasing number of studies on knock-in mice are aimed at understanding the contribution of single amino acids to the stability of DG and to the possible development of muscular dystrophy.
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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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Cabrera-Serrano M, Ghaoui R, Ravenscroft G, Johnsen RD, Davis MR, Corbett A, Reddel S, Sue CM, Liang C, Waddell LB, Kaur S, Lek M, North KN, MacArthur DG, Lamont PJ, Clarke NF, Laing NG. Expanding the phenotype of GMPPB mutations. ACTA ACUST UNITED AC 2015; 138:836-44. [PMID: 25681410 DOI: 10.1093/brain/awv013] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Dystroglycanopathies are a heterogeneous group of diseases with a broad phenotypic spectrum ranging from severe disorders with congenital muscle weakness, eye and brain structural abnormalities and intellectual delay to adult-onset limb-girdle muscular dystrophies without mental retardation. Most frequently the disease onset is congenital or during childhood. The exception is FKRP mutations, in which adult onset is a common presentation. Here we report eight patients from five non-consanguineous families where next generation sequencing identified mutations in the GMPPB gene. Six patients presented as an adult or adolescent-onset limb-girdle muscular dystrophy, one presented with isolated episodes of rhabdomyolysis, and one as a congenital muscular dystrophy. This report expands the phenotypic spectrum of GMPPB mutations to include limb-girdle muscular dystrophies with adult onset with or without intellectual disability, or isolated rhabdomyolysis.
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Affiliation(s)
- Macarena Cabrera-Serrano
- 1 Centre for Medical Research, University of Western Australia, Harry Perkins Institute of Medical Research, Perth, WA, Australia 2 Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | - Roula Ghaoui
- 3 Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, NSW 2145, Australia 4 Discipline of Paediatrics and Child Health, University of Sydney, Sydney, NSW 2006, Australia 5 Department of Neurology, Royal North Shore Hospital, Sydney, Australia
| | - Gianina Ravenscroft
- 1 Centre for Medical Research, University of Western Australia, Harry Perkins Institute of Medical Research, Perth, WA, Australia
| | - Russell D Johnsen
- 6 Centre for Comparative Genomics, Murdoch University, Perth, Australia
| | - Mark R Davis
- 7 Department of Diagnostic Genomics, Pathwest Laboratory Medicine WA. Perth, WA, Australia
| | - Alastair Corbett
- 8 Department of Neurology, Concord Repatriation Hospital, and Sydney Medical School, Sydney, Australia
| | - Stephen Reddel
- 8 Department of Neurology, Concord Repatriation Hospital, and Sydney Medical School, Sydney, Australia
| | - Carolyn M Sue
- 5 Department of Neurology, Royal North Shore Hospital, Sydney, Australia
| | - Christina Liang
- 5 Department of Neurology, Royal North Shore Hospital, Sydney, Australia
| | - Leigh B Waddell
- 3 Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, NSW 2145, Australia 4 Discipline of Paediatrics and Child Health, University of Sydney, Sydney, NSW 2006, Australia
| | - Simranpreet Kaur
- 3 Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, NSW 2145, Australia
| | - Monkol Lek
- 3 Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, NSW 2145, Australia 4 Discipline of Paediatrics and Child Health, University of Sydney, Sydney, NSW 2006, Australia 9 Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA 10 Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Kathryn N North
- 3 Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, NSW 2145, Australia 11 Murdoch Children's Research Institute, The Royal Children's Hospital, Parkville, Victoria, Australia 12 Department of Paediatrics, University of Melbourne, Victoria, Australia
| | - Daniel G MacArthur
- 9 Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA 10 Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Phillipa J Lamont
- 13 Neurogenetic Unit, Department of Neurology, Royal Perth Hospital, Perth, WA, Australia
| | - Nigel F Clarke
- 3 Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, NSW 2145, Australia 4 Discipline of Paediatrics and Child Health, University of Sydney, Sydney, NSW 2006, Australia
| | - Nigel G Laing
- 1 Centre for Medical Research, University of Western Australia, Harry Perkins Institute of Medical Research, Perth, WA, Australia
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Pirolli D, Sciandra F, Bozzi M, Giardina B, Brancaccio A, De Rosa MC. Insights from molecular dynamics simulations: structural basis for the V567D mutation-induced instability of zebrafish alpha-dystroglycan and comparison with the murine model. PLoS One 2014; 9:e103866. [PMID: 25078606 PMCID: PMC4117597 DOI: 10.1371/journal.pone.0103866] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 07/03/2014] [Indexed: 11/19/2022] Open
Abstract
A missense amino acid mutation of valine to aspartic acid in 567 position of alpha-dystroglycan (DG), identified in dag1-mutated zebrafish, results in a reduced transcription and a complete absence of the protein. Lacking experimental structural data for zebrafish DG domains, the detailed mechanism for the observed mutation-induced destabilization of the DG complex and membrane damage, remained unclear. With the aim to contribute to a better clarification of the structure-function relationships featuring the DG complex, three-dimensional structural models of wild-type and mutant (V567D) C-terminal domain of alpha-DG from zebrafish were constructed by a template-based modelling approach. We then ran extensive molecular dynamics (MD) simulations to reveal the structural and dynamic properties of the C-terminal domain and to evaluate the effect of the single mutation on alpha-DG stability. A comparative study has been also carried out on our previously generated model of murine alpha-DG C-terminal domain including the I591D mutation, which is topologically equivalent to the V567D mutation found in zebrafish. Trajectories from MD simulations were analyzed in detail, revealing extensive structural disorder involving multiple beta-strands in the mutated variant of the zebrafish protein whereas local effects have been detected in the murine protein. A biochemical analysis of the murine alpha-DG mutant I591D confirmed a pronounced instability of the protein. Taken together, the computational and biochemical analysis suggest that the V567D/I591D mutation, belonging to the G beta-strand, plays a key role in inducing a destabilization of the alpha-DG C-terminal Ig-like domain that could possibly affect and propagate to the entire DG complex. The structural features herein identified may be of crucial help to understand the molecular basis of primary dystroglycanopathies.
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Affiliation(s)
- Davide Pirolli
- Istituto di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Francesca Sciandra
- Istituto di Chimica del Riconoscimento Molecolare (ICRM) - CNR c/o Università Cattolica del Sacro Cuore, Rome, Italy
| | - Manuela Bozzi
- Istituto di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Bruno Giardina
- Istituto di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Rome, Italy
- Istituto di Chimica del Riconoscimento Molecolare (ICRM) - CNR c/o Università Cattolica del Sacro Cuore, Rome, Italy
| | - Andrea Brancaccio
- Istituto di Chimica del Riconoscimento Molecolare (ICRM) - CNR c/o Università Cattolica del Sacro Cuore, Rome, Italy
| | - Maria Cristina De Rosa
- Istituto di Chimica del Riconoscimento Molecolare (ICRM) - CNR c/o Università Cattolica del Sacro Cuore, Rome, Italy
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Fortunato MJ, Ball CE, Hollinger K, Patel NB, Modi JN, Rajasekaran V, Nonneman DJ, Ross JW, Kennedy EJ, Selsby JT, Beedle AM. Development of rabbit monoclonal antibodies for detection of alpha-dystroglycan in normal and dystrophic tissue. PLoS One 2014; 9:e97567. [PMID: 24824861 PMCID: PMC4019581 DOI: 10.1371/journal.pone.0097567] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 04/21/2014] [Indexed: 12/22/2022] Open
Abstract
Alpha-dystroglycan requires a rare O-mannose glycan modification to form its binding epitope for extracellular matrix proteins such as laminin. This functional glycan is disrupted in a cohort of muscular dystrophies, the secondary dystroglycanopathies, and is abnormal in some metastatic cancers. The most commonly used reagent for detection of alpha-dystroglycan is mouse monoclonal antibody IIH6, but it requires the functional O-mannose structure for recognition. Therefore, the ability to detect alpha-dystroglycan protein in disease states where it lacks the full O-mannose glycan has been limited. To overcome this hurdle, rabbit monoclonal antibodies against the alpha-dystroglycan C-terminus were generated. The new antibodies, named 5–2, 29–5, and 45–3, detect alpha-dystroglycan from mouse, rat and pig skeletal muscle by Western blot and immunofluorescence. In a mouse model of fukutin-deficient dystroglycanopathy, all antibodies detected low molecular weight alpha-dystroglycan in disease samples demonstrating a loss of functional glycosylation. Alternately, in a porcine model of Becker muscular dystrophy, relative abundance of alpha-dystroglycan was decreased, consistent with a reduction in expression of the dystrophin-glycoprotein complex in affected muscle. Therefore, these new rabbit monoclonal antibodies are suitable reagents for alpha-dystroglycan core protein detection and will enhance dystroglycan-related studies.
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Affiliation(s)
- Marisa J. Fortunato
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia, United States of America
| | - Charlotte E. Ball
- Center for Undergraduate Research, University of Georgia, Athens, Georgia, United States of America
| | - Katrin Hollinger
- Department of Animal Science, Iowa State University, Ames, Iowa, United States of America
| | - Niraj B. Patel
- Center for Undergraduate Research, University of Georgia, Athens, Georgia, United States of America
| | - Jill N. Modi
- Center for Undergraduate Research, University of Georgia, Athens, Georgia, United States of America
| | - Vedika Rajasekaran
- Center for Undergraduate Research, University of Georgia, Athens, Georgia, United States of America
| | - Dan J. Nonneman
- United States Department of Agriculture Agricultural Research Service, United States Meat Animal Research Center, Clay Center, Nebraska, United States of America
| | - Jason W. Ross
- Department of Animal Science, Iowa State University, Ames, Iowa, United States of America
| | - Eileen J. Kennedy
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia, United States of America
| | - Joshua T. Selsby
- Department of Animal Science, Iowa State University, Ames, Iowa, United States of America
| | - Aaron M. Beedle
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
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von Renesse A, Petkova MV, Lützkendorf S, Heinemeyer J, Gill E, Hübner C, von Moers A, Stenzel W, Schuelke M. POMK mutation in a family with congenital muscular dystrophy with merosin deficiency, hypomyelination, mild hearing deficit and intellectual disability. J Med Genet 2014; 51:275-82. [PMID: 24556084 DOI: 10.1136/jmedgenet-2013-102236] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND Congenital muscular dystrophies (CMD) with hypoglycosylation of α-dystroglycan are clinically and genetically heterogeneous disorders that are often associated with brain malformations and eye defects. Presently, 16 proteins are known whose dysfunction impedes glycosylation of α-dystroglycan and leads to secondary dystroglycanopathy. OBJECTIVE To identify the cause of CMD with secondary merosin deficiency, hypomyelination and intellectual disability in two siblings from a consanguineous family. METHODS Autozygosity mapping followed by whole exome sequencing and immunochemistry were used to discover and verify a new genetic defect in two siblings with CMD. RESULTS We identified a homozygous missense mutation (c.325C>T, p.Q109*) in protein O-mannosyl kinase (POMK) that encodes a glycosylation-specific kinase (SGK196) required for function of the dystroglycan complex. The protein was absent from skeletal muscle and skin fibroblasts of the patients. In patient muscle, β-dystroglycan was normally expressed at the sarcolemma, while α-dystroglycan failed to do so. Further, we detected co-localisation of POMK with desmin at the costameres in healthy muscle, and a substantial loss of desmin from the patient muscle. CONCLUSIONS Homozygous truncating mutations in POMK lead to CMD with secondary merosin deficiency, hypomyelination and intellectual disability. Loss of desmin suggests that failure of proper α-dystroglycan glycosylation impedes the binding to extracellular matrix proteins and also affects the cytoskeleton.
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Affiliation(s)
- Anja von Renesse
- Department of Neuropediatrics, Charité-Universitätsmedizin Berlin, Berlin, Germany
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Abstract
Advances in genetic tools and sequencing technology in the past few years have vastly expanded our understanding of the genetics of neurodevelopmental disorders. Recent high-throughput sequencing analyses of structural brain malformations, cognitive and neuropsychiatric disorders, and localized cortical dysplasias have uncovered a diverse genetic landscape beyond classic Mendelian patterns of inheritance. The underlying genetic causes of neurodevelopmental disorders implicate numerous cell biological pathways critical for normal brain development.
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Affiliation(s)
- Wen F Hu
- Division of Genetics and Genomics, Department of Medicine; Manton Center for Orphan Disease Research; and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts 02115; , ,
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