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Abstract
Leukodystrophies are genetically determined disorders affecting the white matter of the central nervous system. The combination of MRI pattern recognition and next-generation sequencing for the definition of novel disease entities has recently demonstrated that many leukodystrophies are due to the primary involvement and/or mutations in genes selectively expressed by cell types other than the oligodendrocytes, the myelin-forming cells in the brain. This has led to a new definition of leukodystrophies as genetic white matter disorders resulting from the involvement of any white matter structural component. As a result, the research has shifted its main focus from oligodendrocytes to other types of neuroglia. Astrocytes are the housekeeping cells of the nervous system, responsible for maintaining homeostasis and normal brain physiology and to orchestrate repair upon injury. Several lines of evidence show that astrocytic interactions with the other white matter cellular constituents play a primary pathophysiologic role in many leukodystrophies. These are thus now classified as astrocytopathies. This chapter addresses how the crosstalk between astrocytes, other glial cells, axons and non-neural cells are essential for the integrity and maintenance of the white matter in health. It also addresses the current knowledge of the cellular pathomechanisms of astrocytic leukodystrophies, and specifically Alexander disease, vanishing white matter, megalencephalic leukoencephalopathy with subcortical cysts and Aicardi-Goutière Syndrome.
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Affiliation(s)
- M S Jorge
- Department of Pathology, Free University Medical Centre, Amsterdam, The Netherlands
| | - Marianna Bugiani
- Department of Pathology, Free University Medical Centre, Amsterdam, The Netherlands.
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Elorza-Vidal X, Gaitán-Peñas H, Estévez R. Chloride Channels in Astrocytes: Structure, Roles in Brain Homeostasis and Implications in Disease. Int J Mol Sci 2019; 20:ijms20051034. [PMID: 30818802 PMCID: PMC6429410 DOI: 10.3390/ijms20051034] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 02/15/2019] [Accepted: 02/17/2019] [Indexed: 12/29/2022] Open
Abstract
Astrocytes are the most abundant cell type in the CNS (central nervous system). They exert multiple functions during development and in the adult CNS that are essential for brain homeostasis. Both cation and anion channel activities have been identified in astrocytes and it is believed that they play key roles in astrocyte function. Whereas the proteins and the physiological roles assigned to cation channels are becoming very clear, the study of astrocytic chloride channels is in its early stages. In recent years, we have moved from the identification of chloride channel activities present in astrocyte primary culture to the identification of the proteins involved in these activities, the determination of their 3D structure and attempts to gain insights about their physiological role. Here, we review the recent findings related to the main chloride channels identified in astrocytes: the voltage-dependent ClC-2, the calcium-activated bestrophin, the volume-activated VRAC (volume-regulated anion channel) and the stress-activated Maxi-Cl−. We discuss key aspects of channel biophysics and structure with a focus on their role in glial physiology and human disease.
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Affiliation(s)
- Xabier Elorza-Vidal
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes Disease and Therapy Program IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, 08907 Barcelona, Spain.
- Centro de Investigación en red de enfermedades raras (CIBERER), ISCIII, 08907 Barcelona, Spain.
| | - Héctor Gaitán-Peñas
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes Disease and Therapy Program IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, 08907 Barcelona, Spain.
- Centro de Investigación en red de enfermedades raras (CIBERER), ISCIII, 08907 Barcelona, Spain.
| | - Raúl Estévez
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes Disease and Therapy Program IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, 08907 Barcelona, Spain.
- Centro de Investigación en red de enfermedades raras (CIBERER), ISCIII, 08907 Barcelona, Spain.
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Gilbert A, Vidal XE, Estevez R, Cohen-Salmon M, Boulay AC. Postnatal development of the astrocyte perivascular MLC1/GlialCAM complex defines a temporal window for the gliovascular unit maturation. Brain Struct Funct 2019; 224:1267-1278. [PMID: 30684007 DOI: 10.1007/s00429-019-01832-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 01/08/2019] [Indexed: 12/14/2022]
Abstract
Astrocytes, the most abundant glial cells of the central nervous system are morphologically complex. They display numerous processes interacting with synapses and blood vessels. At the vascular interface, astrocyte endfeet-terminated processes almost entirely cover the blood vessel surface and participate to the gliovascular unit where important vascular properties of the brain are set such as the blood-brain barrier (BBB) integrity. How specific morphological and functional interactions between astrocytes and the vascular compartment develop has not been fully investigated. Here, we elaborated an original experimental strategy to study the postnatal development of astrocyte perivascular endfeet. Using purified gliovascular units, we focused on the postnatal expression of MLC1 and GlialCAM, two transmembrane proteins forming a complex enriched at the junction between mature astrocyte perivascular endfeet. We showed that MLC1 and GlialCAM were enriched and assembled into mature complexes in astrocyte perivascular endfeet between postnatal days 10 and 15, after the formation of astrocyte perivascular Aquaporin 4 water channels. These events correlated with the increased expression of Claudin-5 and P-gP, two endothelial-specific BBB components. These results illustrate for the first time that astrocyte perivascular endfeet differentiation is a complex and progressive process which correlates with BBB maturation. Moreover, our results suggest that maturation of the astrocyte endfeet MLC1/GlialCAM complex between postnatal days 10 and 15 might be a key event in the gliovascular unit maturation.
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Affiliation(s)
- Alice Gilbert
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique CNRS, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale INSERM, U1050, 11 place Marcelin Berthelot Paris, Paris Cedex 05, 75005, France
- Paris Science Lettre Research University, Paris, 75005, France
| | - Xabier Elorza Vidal
- Unitat de Fisiología, Departament de Ciències Fisiològiques, IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Spain
- Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain
| | - Raul Estevez
- Unitat de Fisiología, Departament de Ciències Fisiològiques, IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Spain
- Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain
| | - Martine Cohen-Salmon
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique CNRS, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale INSERM, U1050, 11 place Marcelin Berthelot Paris, Paris Cedex 05, 75005, France.
- Paris Science Lettre Research University, Paris, 75005, France.
| | - Anne-Cécile Boulay
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique CNRS, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale INSERM, U1050, 11 place Marcelin Berthelot Paris, Paris Cedex 05, 75005, France
- Paris Science Lettre Research University, Paris, 75005, France
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Min R, van der Knaap MS. Genetic defects disrupting glial ion and water homeostasis in the brain. Brain Pathol 2019; 28:372-387. [PMID: 29740942 PMCID: PMC8028498 DOI: 10.1111/bpa.12602] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 03/02/2018] [Indexed: 12/23/2022] Open
Abstract
Electrical activity of neurons in the brain, caused by the movement of ions between intracellular and extracellular compartments, is the basis of all our thoughts and actions. Maintaining the correct ionic concentration gradients is therefore crucial for brain functioning. Ion fluxes are accompanied by the displacement of osmotically obliged water. Since even minor brain swelling leads to severe brain damage and even death, brain ion and water movement has to be tightly regulated. Glial cells, in particular astrocytes, play a key role in ion and water homeostasis. They are endowed with specific channels, pumps and carriers to regulate ion and water flow. Glial cells form a large panglial syncytium to aid the uptake and dispersal of ions and water, and make extensive contacts with brain fluid barriers for disposal of excess ions and water. Genetic defects in glial proteins involved in ion and water homeostasis disrupt brain functioning, thereby leading to neurological diseases. Since white matter edema is often a hallmark disease feature, many of these diseases are characterized as leukodystrophies. In this review we summarize our current understanding of inherited glial diseases characterized by disturbed brain ion and water homeostasis by integrating findings from MRI, genetics, neuropathology and animal models for disease. We discuss how mutations in different glial proteins lead to disease, and highlight the similarities and differences between these diseases. To come to effective therapies for this group of diseases, a better mechanistic understanding of how glial cells shape ion and water movement in the brain is crucial.
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Affiliation(s)
- Rogier Min
- Department of Child Neurology, Amsterdam Neuroscience, VU University Medical Center, Amsterdam, The Netherlands.,Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, The Netherlands
| | - Marjo S van der Knaap
- Department of Child Neurology, Amsterdam Neuroscience, VU University Medical Center, Amsterdam, The Netherlands.,Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, The Netherlands
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55
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Identification in Chinese patients with GLIALCAM mutations of megalencephalic leukoencephalopathy with subcortical cysts and brain pathological study on Glialcam knock-in mouse models. World J Pediatr 2019; 15:454-464. [PMID: 31372844 PMCID: PMC6785595 DOI: 10.1007/s12519-019-00284-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Accepted: 06/25/2019] [Indexed: 10/26/2022]
Abstract
BACKGROUND Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare neurological degenerative disorder caused by the mutations of MLC1 or GLIALCAM with autosomal recessive or autosomal dominant inheritance and a different prognosis, characterized by macrocephaly, delayed motor and cognitive development, and bilateral abnormal signals in cerebral white matter (WM) with or without cysts on magnetic resonance imaging (MRI). This study aimed to reveal the clinical and genetic features of MLC patients with GLIALCAM mutations and to explore the brain pathological characteristics and prognosis of mouse models with different modes of inheritance. METHODS Clinical information and peripheral venous blood were collected from six families. Genetic analysis was performed by Sanger sequencing of GLIALCAM. GlialcamArg92Trp/+ and GlialcamLys68Met/Thr132Asn mouse models were generated based on mutations from patients (c.274C>T(p.Arg92Trp) (c.203A>T(p.Lys68Met), and c.395C>A (p.Thr132Asn))). Brain pathologies of the mouse models at different time points were analyzed. RESULTS Six patients were clinically diagnosed with MLC. Of the six patients, five (Pt1-Pt5) presented with a heterozygous mutation in GLIALCAM (c.274C>T(p.Arg92Trp) or c.275G>C(p.Arg92Pro)) and were diagnosed with MLC2B; the remaining patient (Pt6) with two compound heterozygous mutations in GLIALCAM (c.203A>T (p.Lys68Met) and c.395C>A (p.Thr132Asn)) was diagnosed with MLC2A. The mutation c.275C>G (p.Arg92Pro) has not been reported before. Clinical manifestations of the patient with MLC2A (Pt6) progressed with regression, whereas the course of the five MLC2B patients remained stable or improved. The GlialcamArg92Trp/+ and GlialcamLys68Met/ Thr132Asn mouse models showed vacuolization in the anterior commissural WM at 1 month of age and vacuolization in the cerebellar WM at 3 and 6 months, respectively. At 9 months, the vacuolization of the GlialcamLys68Met/ Thr132Asn mouse model was heavier than that of the GlialcamArg92Trp/+ mouse model. Decreased expression of Glialcam in GlialcamArg92Trp/+ and GlialcamLys68Met/ Thr132Asn mice may contribute to the vacuolization. CONCLUSIONS Clinical and genetic characterization of patients with MLC and GLIALCAM mutations revealed a novel mutation, expanding the spectrum of GLIALCAM mutations. The first Glialcam mouse model with autosomal recessive inheritance and a new Glialcam mouse model with autosomal dominant inheritance were generated. The two mouse models with different modes of inheritance showed different degrees of brain pathological features, which were consistent with the patients' phenotype and further confirmed the pathogenicity of the corresponding mutations.
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56
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Elorza-Vidal X, Sirisi S, Gaitán-Peñas H, Pérez-Rius C, Alonso-Gardón M, Armand-Ugón M, Lanciotti A, Brignone MS, Prat E, Nunes V, Ambrosini E, Gasull X, Estévez R. GlialCAM/MLC1 modulates LRRC8/VRAC currents in an indirect manner: Implications for megalencephalic leukoencephalopathy. Neurobiol Dis 2018; 119:88-99. [DOI: 10.1016/j.nbd.2018.07.031] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 07/25/2018] [Accepted: 07/28/2018] [Indexed: 01/09/2023] Open
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Independent occurrence of de novo HSPD1 and HIP1 variants in brothers with different neurological disorders - leukodystrophy and autism. Hum Genome Var 2018; 5:18. [PMID: 30083362 PMCID: PMC6053359 DOI: 10.1038/s41439-018-0020-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Revised: 06/14/2018] [Accepted: 06/22/2018] [Indexed: 11/23/2022] Open
Abstract
Consecutive occurrence of de novo variants in the same family is an extremely rare phenomenon. Two siblings, a younger brother with hypomyelinating leukodystrophy and an elder brother with severe intellectual disability and autistic features, had independent de novo variants of HSPD1 c.139T > G (p.Leu47Val) and HIP1 c.1393G > A (p.Glu465Lys), respectively. These novel variants were predicted to be pathogenic. Both patients also had a known MECP2 variant, c.499C > T (p.Arg167Trp).
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59
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Jentsch TJ, Pusch M. CLC Chloride Channels and Transporters: Structure, Function, Physiology, and Disease. Physiol Rev 2018; 98:1493-1590. [DOI: 10.1152/physrev.00047.2017] [Citation(s) in RCA: 214] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
CLC anion transporters are found in all phyla and form a gene family of eight members in mammals. Two CLC proteins, each of which completely contains an ion translocation parthway, assemble to homo- or heteromeric dimers that sometimes require accessory β-subunits for function. CLC proteins come in two flavors: anion channels and anion/proton exchangers. Structures of these two CLC protein classes are surprisingly similar. Extensive structure-function analysis identified residues involved in ion permeation, anion-proton coupling and gating and led to attractive biophysical models. In mammals, ClC-1, -2, -Ka/-Kb are plasma membrane Cl−channels, whereas ClC-3 through ClC-7 are 2Cl−/H+-exchangers in endolysosomal membranes. Biological roles of CLCs were mostly studied in mammals, but also in plants and model organisms like yeast and Caenorhabditis elegans. CLC Cl−channels have roles in the control of electrical excitability, extra- and intracellular ion homeostasis, and transepithelial transport, whereas anion/proton exchangers influence vesicular ion composition and impinge on endocytosis and lysosomal function. The surprisingly diverse roles of CLCs are highlighted by human and mouse disorders elicited by mutations in their genes. These pathologies include neurodegeneration, leukodystrophy, mental retardation, deafness, blindness, myotonia, hyperaldosteronism, renal salt loss, proteinuria, kidney stones, male infertility, and osteopetrosis. In this review, emphasis is laid on biophysical structure-function analysis and on the cell biological and organismal roles of mammalian CLCs and their role in disease.
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Affiliation(s)
- Thomas J. Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany; and Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy
| | - Michael Pusch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany; and Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy
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60
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Rossi M, Anheim M, Durr A, Klein C, Koenig M, Synofzik M, Marras C, van de Warrenburg BP. The genetic nomenclature of recessive cerebellar ataxias. Mov Disord 2018; 33:1056-1076. [PMID: 29756227 DOI: 10.1002/mds.27415] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/15/2018] [Accepted: 03/25/2018] [Indexed: 12/17/2022] Open
Abstract
The recessive cerebellar ataxias are a large group of degenerative and metabolic disorders, the diagnostic management of which is difficult because of the enormous clinical and genetic heterogeneity. Because of several limitations, the current classification systems provide insufficient guidance for clinicians and researchers. Here, we propose a new nomenclature for the genetically confirmed recessive cerebellar ataxias according to the principles and criteria laid down by the International Parkinson and Movement Disorder Society Task Force on Classification and Nomenclature of Genetic Movement Disorders. We apply stringent criteria for considering an association between gene and phenotype to be established. The newly proposed list of recessively inherited cerebellar ataxias includes 62 disorders that were assigned an ATX prefix, followed by the gene name, because these typically present with ataxia as a predominant and/or consistent feature. An additional 30 disorders that often combine ataxia with a predominant or consistent other movement disorder received a double prefix (e.g., ATX/HSP). We also identified a group of 89 entities that usually present with complex nonataxia phenotypes, but may occasionally present with cerebellar ataxia. These are listed separately without the ATX prefix. This new, transparent and adaptable nomenclature of the recessive cerebellar ataxias will facilitate the clinical recognition of recessive ataxias, guide diagnostic testing in ataxia patients, and help in interpreting genetic findings. © 2018 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Malco Rossi
- Movement Disorders Section, Neuroscience Department, Raul Carrea Institute for Neurological Research, Buenos Aires, Argentina
| | - Mathieu Anheim
- Département de Neurologie, Hôpitaux Universitaires de Strasbourg, Hôpital de Hautepierre, Strasbourg, France.,Institut de Génétique et de Biologie Moléculaire et Cellulaire, INSERM-U964/CNRS-UMR7104/Université de Strasbourg, Illkirch, France.,Fédération de Médecine Translationnelle de Strasbourg, Université de Strasbourg, Strasbourg, France
| | - Alexandra Durr
- Brain and Spine Institute, Sorbonne Université, Inserm U1127, CNRS UMR 7225, Pitié-Salpêtrière University Hospital, Paris, France.,Department of Genetics, AP-HP, Pitié-Salpêtrière University Hospital, 7501, Paris, France
| | - Christine Klein
- Institute of Neurogenetics, University of Luebeck, Luebeck, Germany.,Department of Neurology, University Hospital Schleswig-Holstein, Campus Lübeck, Germany
| | - Michel Koenig
- Laboratoire de Génétique de Maladies Rares, EA7402, Institut Universitaire de Recherche Clinique, Université de Montpellier, CHU Montpellier, Montpellier, France
| | - Matthis Synofzik
- Department of Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,German Center for Neurodegenerative Diseases, Tübingen, Germany
| | - Connie Marras
- Toronto Western Hospital Morton, Gloria Shulman Movement Disorders Centre, and the Edmond J. Safra Program in Parkinson's Disease, University of Toronto, Toronto, Canada
| | - Bart P van de Warrenburg
- Department of Neurology, Donders Institute for Brain, Cognition & Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
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Stutterd CA, Lake NJ, Peters H, Lockhart PJ, Taft RJ, van der Knaap MS, Vanderver A, Thorburn DR, Simons C, Leventer RJ. Severe Leukoencephalopathy with Clinical Recovery Caused by Recessive BOLA3 Mutations. JIMD Rep 2018; 43:63-70. [PMID: 29654549 PMCID: PMC6323033 DOI: 10.1007/8904_2018_100] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 02/26/2018] [Accepted: 03/01/2018] [Indexed: 03/10/2023] Open
Abstract
AIM To identify the genetic aetiology of a distinct leukoencephalopathy causing acute neurological regression in infancy with apparently complete clinical recovery. METHODS We performed trio whole genome sequencing (WGS) to determine the genetic basis of the disorder. Mitochondrial function analysis in cultured patient fibroblasts was undertaken to confirm the pathogenicity of candidate variants. RESULTS The patient presented at 18 months with acute hemiplegia and cognitive regression without obvious trigger. This was followed by clinical recovery over 4 years. MRI at disease onset revealed bilateral T2 hyperintensity involving the periventricular and deep white matter and MR spectroscopy of frontal white matter demonstrated a lactate doublet. Lactate levels and mitochondrial respiratory chain enzyme activity in muscle, liver and fibroblasts were normal. Plasma glycine was elevated. The MRI abnormalities improved. WGS identified compound heterozygous variants in BOLA3: one previously reported (c.136C>T, p.Arg46*) and one novel variant (c.176G>A, p.Cys59Tyr). Analysis of cultured patient fibroblasts demonstrated deficient pyruvate dehydrogenase (PDH) activity and reduced quantity of protein subunits of mitochondrial complexes I and II, consistent with BOLA3 dysfunction. Previously reported cases of multiple mitochondrial dysfunctions syndrome 2 (MMDS2) with hyperglycinaemia caused by BOLA3 mutations have leukodystrophy with severe, progressive neurological and multisystem disease. CONCLUSIONS We report a novel phenotype for MMDS2 associated with apparently complete clinical recovery and partial resolution of MRI abnormalities. We have identified a novel disease-causing variant in BOLA3 validated by functional cellular studies. Our patient's clinical course broadens the phenotypic spectrum of MMDS2 and highlights the potential for some genetic leukoencephalopathies to spontaneously improve.
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Affiliation(s)
- C A Stutterd
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, Parkville, VIC, Australia.
- Department of Neurology, Royal Children's Hospital, Parkville, VIC, Australia.
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Parkville, VIC, Australia.
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia.
| | - N J Lake
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
- Mitochondrial Research Group, Murdoch Children's Research Institute, Parkville, VIC, Australia
| | - H Peters
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
- Department of Metabolic Medicine, Royal Children's Hospital, Parkville, VIC, Australia
- Metabolic Research Group, Murdoch Children's Research Institute, Parkville, VIC, Australia
| | - P J Lockhart
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, Parkville, VIC, Australia
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
| | - R J Taft
- Illumina Inc, San Diego, CA, USA
| | - M S van der Knaap
- Department of Child Neurology, VU University Medical Center, Amsterdam, The Netherlands
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam, The Netherlands
| | - A Vanderver
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - D R Thorburn
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Parkville, VIC, Australia
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
- Mitochondrial Research Group, Murdoch Children's Research Institute, Parkville, VIC, Australia
| | - C Simons
- Institute for Molecular Bioscience, University of Queensland, St Lucia, QLD, Australia
- Translational Bioinformatics Research Group, Murdoch Children's Research Institute, Parkville, VIC, Australia
| | - R J Leventer
- Department of Neurology, Royal Children's Hospital, Parkville, VIC, Australia
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
- Neuroscience Research Group, Murdoch Children's Research Institute, Parkville, VIC, Australia
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62
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Hamilton EMC, Tekturk P, Cialdella F, van Rappard DF, Wolf NI, Yalcinkaya C, Çetinçelik Ü, Rajaee A, Kariminejad A, Paprocka J, Yapici Z, Bošnjak VM, van der Knaap MS. Megalencephalic leukoencephalopathy with subcortical cysts: Characterization of disease variants. Neurology 2018; 90:e1395-e1403. [PMID: 29661901 PMCID: PMC5902784 DOI: 10.1212/wnl.0000000000005334] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 01/16/2018] [Indexed: 01/08/2023] Open
Abstract
Objective To provide an overview of clinical and MRI characteristics of the different variants of the leukodystrophy megalencephalic leukoencephalopathy with subcortical cysts (MLC) and identify possible differentiating features. Methods We performed an international multi-institutional, cross-sectional observational study of the clinical and MRI characteristics in patients with genetically confirmed MLC. Clinical information was obtained by questionnaires for physicians and retrospective chart review. Results We included 204 patients with classic MLC, 187 of whom had recessive mutations in MLC1 (MLC1 variant) and 17 in GLIALCAM (MLC2A variant) and 38 patients with remitting MLC caused by dominant GLIALCAM mutations (MLC2B variant). We observed a relatively wide variability in neurologic disability among patients with classic MLC. No clinical differences could be identified between patients with MLC1 and MLC2A. Patients with MLC2B invariably had a milder phenotype with preservation of motor function, while intellectual disability and autism were relatively frequent. Systematic MRI review revealed no MRI features that distinguish between MLC1 and MLC2A. Radiologic improvement was observed in all patients with MLC2B and also in 2 patients with MLC1. In MRIs obtained in the early disease stage, absence of signal abnormalities of the posterior limb of the internal capsule and cerebellar white matter and presence of only rarefied subcortical white matter instead of true subcortical cysts were suggestive of MLC2B. Conclusion Clinical and MRI features did not distinguish between classic MLC with MLC1 or GLIALCAM mutations. Absence of signal abnormalities of the internal capsule and cerebellar white matter are MRI findings that point to the remitting phenotype.
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Affiliation(s)
- Eline M C Hamilton
- From the Department of Child Neurology and Amsterdam Neuroscience (E.M.C.H., F.C., D.F.v.R., N.I.W., M.S.v.d.K.), VU University Medical Center, Amsterdam, the Netherlands; Division of Child Neurology, Department of Neurology, Istanbul Faculty of Medicine (P.T., Z.Y.), and Division of Child Neurology, Department of Neurology, Cerrahpasa Medical School (C.Y.), Istanbul University; clinical geneticist in private practice (Ü.Ç.), Merkez Mahallesi, İstanbul, Turkey; Kariminejad-Najmabadi Pathology & Genetics Center (A.R., A.K.), Tehran, Iran; Department of Pediatric Neurology (J.P.), School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland; Department of Neuropediatrics (V.M.B.), Children's Hospital Zagreb, School of Medicine, University of Zagreb, Croatia; and Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, the Netherlands
| | - Pinar Tekturk
- From the Department of Child Neurology and Amsterdam Neuroscience (E.M.C.H., F.C., D.F.v.R., N.I.W., M.S.v.d.K.), VU University Medical Center, Amsterdam, the Netherlands; Division of Child Neurology, Department of Neurology, Istanbul Faculty of Medicine (P.T., Z.Y.), and Division of Child Neurology, Department of Neurology, Cerrahpasa Medical School (C.Y.), Istanbul University; clinical geneticist in private practice (Ü.Ç.), Merkez Mahallesi, İstanbul, Turkey; Kariminejad-Najmabadi Pathology & Genetics Center (A.R., A.K.), Tehran, Iran; Department of Pediatric Neurology (J.P.), School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland; Department of Neuropediatrics (V.M.B.), Children's Hospital Zagreb, School of Medicine, University of Zagreb, Croatia; and Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, the Netherlands
| | - Fia Cialdella
- From the Department of Child Neurology and Amsterdam Neuroscience (E.M.C.H., F.C., D.F.v.R., N.I.W., M.S.v.d.K.), VU University Medical Center, Amsterdam, the Netherlands; Division of Child Neurology, Department of Neurology, Istanbul Faculty of Medicine (P.T., Z.Y.), and Division of Child Neurology, Department of Neurology, Cerrahpasa Medical School (C.Y.), Istanbul University; clinical geneticist in private practice (Ü.Ç.), Merkez Mahallesi, İstanbul, Turkey; Kariminejad-Najmabadi Pathology & Genetics Center (A.R., A.K.), Tehran, Iran; Department of Pediatric Neurology (J.P.), School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland; Department of Neuropediatrics (V.M.B.), Children's Hospital Zagreb, School of Medicine, University of Zagreb, Croatia; and Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, the Netherlands
| | - Diane F van Rappard
- From the Department of Child Neurology and Amsterdam Neuroscience (E.M.C.H., F.C., D.F.v.R., N.I.W., M.S.v.d.K.), VU University Medical Center, Amsterdam, the Netherlands; Division of Child Neurology, Department of Neurology, Istanbul Faculty of Medicine (P.T., Z.Y.), and Division of Child Neurology, Department of Neurology, Cerrahpasa Medical School (C.Y.), Istanbul University; clinical geneticist in private practice (Ü.Ç.), Merkez Mahallesi, İstanbul, Turkey; Kariminejad-Najmabadi Pathology & Genetics Center (A.R., A.K.), Tehran, Iran; Department of Pediatric Neurology (J.P.), School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland; Department of Neuropediatrics (V.M.B.), Children's Hospital Zagreb, School of Medicine, University of Zagreb, Croatia; and Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, the Netherlands
| | - Nicole I Wolf
- From the Department of Child Neurology and Amsterdam Neuroscience (E.M.C.H., F.C., D.F.v.R., N.I.W., M.S.v.d.K.), VU University Medical Center, Amsterdam, the Netherlands; Division of Child Neurology, Department of Neurology, Istanbul Faculty of Medicine (P.T., Z.Y.), and Division of Child Neurology, Department of Neurology, Cerrahpasa Medical School (C.Y.), Istanbul University; clinical geneticist in private practice (Ü.Ç.), Merkez Mahallesi, İstanbul, Turkey; Kariminejad-Najmabadi Pathology & Genetics Center (A.R., A.K.), Tehran, Iran; Department of Pediatric Neurology (J.P.), School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland; Department of Neuropediatrics (V.M.B.), Children's Hospital Zagreb, School of Medicine, University of Zagreb, Croatia; and Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, the Netherlands
| | - Cengiz Yalcinkaya
- From the Department of Child Neurology and Amsterdam Neuroscience (E.M.C.H., F.C., D.F.v.R., N.I.W., M.S.v.d.K.), VU University Medical Center, Amsterdam, the Netherlands; Division of Child Neurology, Department of Neurology, Istanbul Faculty of Medicine (P.T., Z.Y.), and Division of Child Neurology, Department of Neurology, Cerrahpasa Medical School (C.Y.), Istanbul University; clinical geneticist in private practice (Ü.Ç.), Merkez Mahallesi, İstanbul, Turkey; Kariminejad-Najmabadi Pathology & Genetics Center (A.R., A.K.), Tehran, Iran; Department of Pediatric Neurology (J.P.), School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland; Department of Neuropediatrics (V.M.B.), Children's Hospital Zagreb, School of Medicine, University of Zagreb, Croatia; and Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, the Netherlands
| | - Ümran Çetinçelik
- From the Department of Child Neurology and Amsterdam Neuroscience (E.M.C.H., F.C., D.F.v.R., N.I.W., M.S.v.d.K.), VU University Medical Center, Amsterdam, the Netherlands; Division of Child Neurology, Department of Neurology, Istanbul Faculty of Medicine (P.T., Z.Y.), and Division of Child Neurology, Department of Neurology, Cerrahpasa Medical School (C.Y.), Istanbul University; clinical geneticist in private practice (Ü.Ç.), Merkez Mahallesi, İstanbul, Turkey; Kariminejad-Najmabadi Pathology & Genetics Center (A.R., A.K.), Tehran, Iran; Department of Pediatric Neurology (J.P.), School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland; Department of Neuropediatrics (V.M.B.), Children's Hospital Zagreb, School of Medicine, University of Zagreb, Croatia; and Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, the Netherlands
| | - Ahmad Rajaee
- From the Department of Child Neurology and Amsterdam Neuroscience (E.M.C.H., F.C., D.F.v.R., N.I.W., M.S.v.d.K.), VU University Medical Center, Amsterdam, the Netherlands; Division of Child Neurology, Department of Neurology, Istanbul Faculty of Medicine (P.T., Z.Y.), and Division of Child Neurology, Department of Neurology, Cerrahpasa Medical School (C.Y.), Istanbul University; clinical geneticist in private practice (Ü.Ç.), Merkez Mahallesi, İstanbul, Turkey; Kariminejad-Najmabadi Pathology & Genetics Center (A.R., A.K.), Tehran, Iran; Department of Pediatric Neurology (J.P.), School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland; Department of Neuropediatrics (V.M.B.), Children's Hospital Zagreb, School of Medicine, University of Zagreb, Croatia; and Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, the Netherlands
| | - Ariana Kariminejad
- From the Department of Child Neurology and Amsterdam Neuroscience (E.M.C.H., F.C., D.F.v.R., N.I.W., M.S.v.d.K.), VU University Medical Center, Amsterdam, the Netherlands; Division of Child Neurology, Department of Neurology, Istanbul Faculty of Medicine (P.T., Z.Y.), and Division of Child Neurology, Department of Neurology, Cerrahpasa Medical School (C.Y.), Istanbul University; clinical geneticist in private practice (Ü.Ç.), Merkez Mahallesi, İstanbul, Turkey; Kariminejad-Najmabadi Pathology & Genetics Center (A.R., A.K.), Tehran, Iran; Department of Pediatric Neurology (J.P.), School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland; Department of Neuropediatrics (V.M.B.), Children's Hospital Zagreb, School of Medicine, University of Zagreb, Croatia; and Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, the Netherlands
| | - Justyna Paprocka
- From the Department of Child Neurology and Amsterdam Neuroscience (E.M.C.H., F.C., D.F.v.R., N.I.W., M.S.v.d.K.), VU University Medical Center, Amsterdam, the Netherlands; Division of Child Neurology, Department of Neurology, Istanbul Faculty of Medicine (P.T., Z.Y.), and Division of Child Neurology, Department of Neurology, Cerrahpasa Medical School (C.Y.), Istanbul University; clinical geneticist in private practice (Ü.Ç.), Merkez Mahallesi, İstanbul, Turkey; Kariminejad-Najmabadi Pathology & Genetics Center (A.R., A.K.), Tehran, Iran; Department of Pediatric Neurology (J.P.), School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland; Department of Neuropediatrics (V.M.B.), Children's Hospital Zagreb, School of Medicine, University of Zagreb, Croatia; and Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, the Netherlands
| | - Zuhal Yapici
- From the Department of Child Neurology and Amsterdam Neuroscience (E.M.C.H., F.C., D.F.v.R., N.I.W., M.S.v.d.K.), VU University Medical Center, Amsterdam, the Netherlands; Division of Child Neurology, Department of Neurology, Istanbul Faculty of Medicine (P.T., Z.Y.), and Division of Child Neurology, Department of Neurology, Cerrahpasa Medical School (C.Y.), Istanbul University; clinical geneticist in private practice (Ü.Ç.), Merkez Mahallesi, İstanbul, Turkey; Kariminejad-Najmabadi Pathology & Genetics Center (A.R., A.K.), Tehran, Iran; Department of Pediatric Neurology (J.P.), School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland; Department of Neuropediatrics (V.M.B.), Children's Hospital Zagreb, School of Medicine, University of Zagreb, Croatia; and Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, the Netherlands
| | - Vlatka Mejaški Bošnjak
- From the Department of Child Neurology and Amsterdam Neuroscience (E.M.C.H., F.C., D.F.v.R., N.I.W., M.S.v.d.K.), VU University Medical Center, Amsterdam, the Netherlands; Division of Child Neurology, Department of Neurology, Istanbul Faculty of Medicine (P.T., Z.Y.), and Division of Child Neurology, Department of Neurology, Cerrahpasa Medical School (C.Y.), Istanbul University; clinical geneticist in private practice (Ü.Ç.), Merkez Mahallesi, İstanbul, Turkey; Kariminejad-Najmabadi Pathology & Genetics Center (A.R., A.K.), Tehran, Iran; Department of Pediatric Neurology (J.P.), School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland; Department of Neuropediatrics (V.M.B.), Children's Hospital Zagreb, School of Medicine, University of Zagreb, Croatia; and Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, the Netherlands
| | - Marjo S van der Knaap
- From the Department of Child Neurology and Amsterdam Neuroscience (E.M.C.H., F.C., D.F.v.R., N.I.W., M.S.v.d.K.), VU University Medical Center, Amsterdam, the Netherlands; Division of Child Neurology, Department of Neurology, Istanbul Faculty of Medicine (P.T., Z.Y.), and Division of Child Neurology, Department of Neurology, Cerrahpasa Medical School (C.Y.), Istanbul University; clinical geneticist in private practice (Ü.Ç.), Merkez Mahallesi, İstanbul, Turkey; Kariminejad-Najmabadi Pathology & Genetics Center (A.R., A.K.), Tehran, Iran; Department of Pediatric Neurology (J.P.), School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland; Department of Neuropediatrics (V.M.B.), Children's Hospital Zagreb, School of Medicine, University of Zagreb, Croatia; and Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, the Netherlands.
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Dubey M, Brouwers E, Hamilton EM, Stiedl O, Bugiani M, Koch H, Kole MH, Boschert U, Wykes RC, Mansvelder HD, van der Knaap MS, Min R. Seizures and disturbed brain potassium dynamics in the leukodystrophy megalencephalic leukoencephalopathy with subcortical cysts. Ann Neurol 2018; 83:636-649. [PMID: 29466841 PMCID: PMC5900999 DOI: 10.1002/ana.25190] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 01/12/2018] [Accepted: 02/18/2018] [Indexed: 12/26/2022]
Abstract
OBJECTIVE Loss of function of the astrocyte-specific protein MLC1 leads to the childhood-onset leukodystrophy "megalencephalic leukoencephalopathy with subcortical cysts" (MLC). Studies on isolated cells show a role for MLC1 in astrocyte volume regulation and suggest that disturbed brain ion and water homeostasis is central to the disease. Excitability of neuronal networks is particularly sensitive to ion and water homeostasis. In line with this, reports of seizures and epilepsy in MLC patients exist. However, systematic assessment and mechanistic understanding of seizures in MLC are lacking. METHODS We analyzed an MLC patient inventory to study occurrence of seizures in MLC. We used two distinct genetic mouse models of MLC to further study epileptiform activity and seizure threshold through wireless extracellular field potential recordings. Whole-cell patch-clamp recordings and K+ -sensitive electrode recordings in mouse brain slices were used to explore the underlying mechanisms of epilepsy in MLC. RESULTS An early onset of seizures is common in MLC. Similarly, in MLC mice, we uncovered spontaneous epileptiform brain activity and a lowered threshold for induced seizures. At the cellular level, we found that although passive and active properties of individual pyramidal neurons are unchanged, extracellular K+ dynamics and neuronal network activity are abnormal in MLC mice. INTERPRETATION Disturbed astrocyte regulation of ion and water homeostasis in MLC causes hyperexcitability of neuronal networks and seizures. These findings suggest a role for defective astrocyte volume regulation in epilepsy. Ann Neurol 2018;83:636-649.
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Affiliation(s)
- Mohit Dubey
- Department of Child Neurology, Amsterdam NeuroscienceVU University Medical CenterAmsterdamThe Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam NeuroscienceVU UniversityAmsterdamThe Netherlands
- Present address:
Current address for Mohit Dubey: Department of Axonal SignalingNetherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and SciencesAmsterdamThe Netherlands
| | - Eelke Brouwers
- Department of Child Neurology, Amsterdam NeuroscienceVU University Medical CenterAmsterdamThe Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam NeuroscienceVU UniversityAmsterdamThe Netherlands
| | - Eline M.C. Hamilton
- Department of Child Neurology, Amsterdam NeuroscienceVU University Medical CenterAmsterdamThe Netherlands
| | - Oliver Stiedl
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Amsterdam NeuroscienceVU UniversityAmsterdamThe Netherlands
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam NeuroscienceVU UniversityAmsterdamThe Netherlands
| | - Marianna Bugiani
- Department of Child Neurology, Amsterdam NeuroscienceVU University Medical CenterAmsterdamThe Netherlands
- Department of PathologyVU University Medical CenterAmsterdamThe Netherlands
| | - Henner Koch
- Department of NeurologyUniversity of Tübingen, Hertie Institute for Clinical Brain ResearchTübingenGermany
| | - Maarten H.P. Kole
- Department of Axonal SignalingNetherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and SciencesAmsterdamThe Netherlands
- Cell Biology, Faculty of ScienceUtrecht UniversityUtrechtThe Netherlands
| | - Ursula Boschert
- Translational Innovation Platform Immunology/Neurology, EMD Serono Research & Development InstituteBillericaMA
| | - Robert C. Wykes
- Department of Clinical & Experimental Epilepsy, UCL Institute of NeurologyUniversity College LondonLondonUnited Kingdom
| | - Huibert D. Mansvelder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam NeuroscienceVU UniversityAmsterdamThe Netherlands
| | - Marjo S. van der Knaap
- Department of Child Neurology, Amsterdam NeuroscienceVU University Medical CenterAmsterdamThe Netherlands
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Amsterdam NeuroscienceVU UniversityAmsterdamThe Netherlands
| | - Rogier Min
- Department of Child Neurology, Amsterdam NeuroscienceVU University Medical CenterAmsterdamThe Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam NeuroscienceVU UniversityAmsterdamThe Netherlands
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64
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Abstract
The leukodystrophies are a group of inherited white matter disorders with a heterogeneous genetic background, considerable phenotypic variability and disease onset at all ages. This Review focuses on leukodystrophies with major prevalence or primary onset in adulthood. We summarize 20 leukodystrophies with adult presentations, providing information on the underlying genetic mutations and on biochemical assays that aid diagnosis, where available. Definitions, clinical characteristics, age of onset, MRI findings and treatment options are all described, providing a comprehensive overview of the current knowledge of the various adulthood leukodystrophies. We highlight the distinction between adult-onset leukodystrophies and other inherited disorders with white matter involvement, and we propose a diagnostic pathway for timely recognition of adulthood leukodystrophies in a routine clinical setting. In addition, we provide detailed clinical information on selected adult-onset leukodystrophies, including X-linked adrenoleukodystrophy, metachromatic leukodystrophy, cerebrotendinous xanthomatosis, hereditary diffuse leukoencephalopathy with axonal spheroids, autosomal dominant adult-onset demyelinating leukodystrophy, adult polyglucosan body disease, and leukoencephalopathy with vanishing white matter. Ultimately, this Review aims to provide helpful suggestions to identify treatable adulthood leukodystrophies at an early stage in the disease course.
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Affiliation(s)
- Wolfgang Köhler
- Department of Neurology, University Hospital Leipzig, Liebigstrasse 20, 04103 Leipzig, Germany
| | - Julian Curiel
- Division of Neurology, Children's Hospital of Philadelphia, Abramson Research Center, 3615 Civic Center Boulevard, Philadelphia, Pennsylvania 19104, USA
| | - Adeline Vanderver
- Division of Neurology, Children's Hospital of Philadelphia, Abramson Research Center, 3615 Civic Center Boulevard, Philadelphia, Pennsylvania 19104, USA
- Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Boulevard, Philadelphia, Pennsylvania 19104, USA
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Kurahashi H, Azuma Y, Masuda A, Okuno T, Nakahara E, Imamura T, Saitoh M, Mizuguchi M, Shimizu T, Ohno K, Okumura A. MYRF is associated with encephalopathy with reversible myelin vacuolization. Ann Neurol 2018; 83:98-106. [PMID: 29265453 DOI: 10.1002/ana.25125] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 12/14/2017] [Accepted: 12/15/2017] [Indexed: 01/04/2023]
Abstract
OBJECTIVE Reversible myelin vacuolization is associated with variable conditions including mild encephalitis/encephalopathy with a reversible splenial lesion (MERS), which is characterized by mildly impaired consciousness and transient splenial lesion. Familial and/or recurrent cases with a clinical diagnosis of MERS suggest the presence of genetic factors. METHODS We examined a family in which the proband presented with a history of recurrent encephalopathy with extensive but reversible cerebral myelin vacuolization and neurological symptoms similar to those of MERS spanning 3 generations. Whole-exome sequencing was performed in family members. RESULTS Eight rare nonsynonymous single-nucleotide variants shared by all patients were identified. By filtering genes expressed in the corpus callosum, we identified a heterozygous c.1208A>G predicting p.Gln403Arg in the highly conserved DNA-binding domain in the myelin regulatory factor (MYRF) gene. We subsequently screened the coding regions of MYRF by Sanger sequencing in our cohort comprised of 33 sporadic cases with MERS and 3 cases in another family with extensive myelin vacuolization, and identified the same heterozygous c.1208A>G in all affected members in the second family. Luciferase assay revealed that transcriptional activity of the N-terminal region of MYRF was significantly diminished by introducing the c.1208A>G variant. INTERPRETATION MYRF is a transcriptional regulator that is necessary for oligodendrocyte differentiation and myelin maintenance. Functional defects of MYRF are likely to be causally associated with encephalopathy with extensive myelin vacuolization. We propose the term "MYRF-related mild encephalopathy with reversible myelin vacuolization." Our findings provide a new perspective on the pathogenesis of myelin vacuolization. Ann Neurol 2018;83:98-106.
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Affiliation(s)
- Hirokazu Kurahashi
- Department of Pediatrics, Aichi Medical University, Nagakute, Aichi, Japan
| | - Yoshiteru Azuma
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.,Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, Tyne and Wear, United Kingdom
| | - Akio Masuda
- Division of Neurogenetics, Center for Neurological Disease and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Tatsuya Okuno
- Division of Neurogenetics, Center for Neurological Disease and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Eri Nakahara
- Department of Pediatrics, Juntendo University Faculty of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Takuji Imamura
- Department of Pediatrics, PL General Hospital, Tondabayashi, Osaka, Japan
| | - Makiko Saitoh
- Department of Developmental Medical Sciences, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Masashi Mizuguchi
- Department of Developmental Medical Sciences, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Toshiaki Shimizu
- Department of Pediatrics, Juntendo University Faculty of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Kinji Ohno
- Division of Neurogenetics, Center for Neurological Disease and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Akihisa Okumura
- Department of Pediatrics, Aichi Medical University, Nagakute, Aichi, Japan.,Department of Pediatrics, Juntendo University Faculty of Medicine, Bunkyo-ku, Tokyo, Japan
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66
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Estévez R, Elorza-Vidal X, Gaitán-Peñas H, Pérez-Rius C, Armand-Ugón M, Alonso-Gardón M, Xicoy-Espaulella E, Sirisi S, Arnedo T, Capdevila-Nortes X, López-Hernández T, Montolio M, Duarri A, Teijido O, Barrallo-Gimeno A, Palacín M, Nunes V. Megalencephalic leukoencephalopathy with subcortical cysts: A personal biochemical retrospective. Eur J Med Genet 2018; 61:50-60. [DOI: 10.1016/j.ejmg.2017.10.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 09/14/2017] [Accepted: 10/22/2017] [Indexed: 12/22/2022]
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Gaitán-Peñas H, Apaja PM, Arnedo T, Castellanos A, Elorza-Vidal X, Soto D, Gasull X, Lukacs GL, Estévez R. Leukoencephalopathy-causing CLCN2 mutations are associated with impaired Cl - channel function and trafficking. J Physiol 2017; 595:6993-7008. [PMID: 28905383 DOI: 10.1113/jp275087] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 09/11/2017] [Indexed: 01/30/2023] Open
Abstract
KEY POINTS Characterisation of most mutations found in CLCN2 in patients with CC2L leukodystrophy show that they cause a reduction in function of the chloride channel ClC-2. GlialCAM, a regulatory subunit of ClC-2 in glial cells and involved in the leukodystrophy megalencephalic leukoencephalopathy with subcortical cysts (MLC), increases the activity of a ClC-2 mutant by affecting ClC-2 gating and by stabilising the mutant at the plasma membrane. The stabilisation of ClC-2 at the plasma membrane by GlialCAM depends on its localisation at cell-cell junctions. The membrane protein MLC1, which is defective in MLC, also contributes to the stabilisation of ClC-2 at the plasma membrane, providing further support for the view that GlialCAM, MLC1 and ClC-2 form a protein complex in glial cells. ABSTRACT Mutations in CLCN2 have been recently identified in patients suffering from a type of leukoencephalopathy involving intramyelinic oedema. Here, we characterised most of these mutations that reduce the function of the chloride channel ClC-2 and impair its plasma membrane (PM) expression. Detailed biochemical and electrophysiological analyses of the Ala500Val mutation revealed that defective gating and increased cellular and PM turnover contributed to defective A500V-ClC-2 functional expression. Co-expression of the adhesion molecule GlialCAM, which forms a tertiary complex with ClC-2 and megalencephalic leukoencephalopathy with subcortical cysts 1 (MLC1), rescued the functional expression of the mutant by modifying its gating properties. GlialCAM also restored the PM levels of the channel by impeding its turnover at the PM. This rescue required ClC-2 localisation to cell-cell junctions, since a GlialCAM mutant with compromised junctional localisation failed to rescue the impaired stability of mutant ClC-2 at the PM. Wild-type, but not mutant, ClC-2 was also stabilised by MLC1 overexpression. We suggest that leukodystrophy-causing CLCN2 mutations reduce the functional expression of ClC-2, which is partly counteracted by GlialCAM/MLC1-mediated increase in the gating and stability of the channel.
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Affiliation(s)
- Héctor Gaitán-Peñas
- Unitat de Fisiología, Departament de Ciències Fisiològiques, IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Spain.,Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Spain
| | - Pirjo M Apaja
- Department of Physiology, McGill University, Montréal, Quebec, H3E 1Y6, Canada.,Research Group Focused on Protein Structure, McGill University, Montréal, Quebec, H3E 1Y6, Canada.,South Australian Health and Medical Research Institute, Nutrition and Metabolism Theme and EMBL Australia, 5000, Adelaide, Australia
| | - Tanit Arnedo
- Unitat de Fisiología, Departament de Ciències Fisiològiques, IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Spain.,Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Spain
| | - Aida Castellanos
- Neurophysiology Laboratory, Physiology Unit, Department of Biomedicine, Medical School, Institute of Neurosciences, IDIBAPS, University of Barcelona, Barcelona, Spain
| | - Xabier Elorza-Vidal
- Unitat de Fisiología, Departament de Ciències Fisiològiques, IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Spain.,Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Spain
| | - David Soto
- Neurophysiology Laboratory, Physiology Unit, Department of Biomedicine, Medical School, Institute of Neurosciences, IDIBAPS, University of Barcelona, Barcelona, Spain
| | - Xavier Gasull
- Neurophysiology Laboratory, Physiology Unit, Department of Biomedicine, Medical School, Institute of Neurosciences, IDIBAPS, University of Barcelona, Barcelona, Spain
| | - Gergely L Lukacs
- Department of Physiology, McGill University, Montréal, Quebec, H3E 1Y6, Canada.,Research Group Focused on Protein Structure, McGill University, Montréal, Quebec, H3E 1Y6, Canada
| | - Raúl Estévez
- Unitat de Fisiología, Departament de Ciències Fisiològiques, IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Spain.,Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Spain
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68
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van der Knaap MS, Bugiani M. Leukodystrophies: a proposed classification system based on pathological changes and pathogenetic mechanisms. Acta Neuropathol 2017; 134:351-382. [PMID: 28638987 PMCID: PMC5563342 DOI: 10.1007/s00401-017-1739-1] [Citation(s) in RCA: 222] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 06/06/2017] [Accepted: 06/06/2017] [Indexed: 12/29/2022]
Abstract
Leukodystrophies are genetically determined disorders characterized by the selective involvement of the central nervous system white matter. Onset may be at any age, from prenatal life to senescence. Many leukodystrophies are degenerative in nature, but some only impair white matter function. The clinical course is mostly progressive, but may also be static or even improving with time. Progressive leukodystrophies are often fatal, and no curative treatment is known. The last decade has witnessed a tremendous increase in the number of defined leukodystrophies also owing to a diagnostic approach combining magnetic resonance imaging pattern recognition and next generation sequencing. Knowledge on white matter physiology and pathology has also dramatically built up. This led to the recognition that only few leukodystrophies are due to mutations in myelin- or oligodendrocyte-specific genes, and many are rather caused by defects in other white matter structural components, including astrocytes, microglia, axons and blood vessels. We here propose a novel classification of leukodystrophies that takes into account the primary involvement of any white matter component. Categories in this classification are the myelin disorders due to a primary defect in oligodendrocytes or myelin (hypomyelinating and demyelinating leukodystrophies, leukodystrophies with myelin vacuolization); astrocytopathies; leuko-axonopathies; microgliopathies; and leuko-vasculopathies. Following this classification, we illustrate the neuropathology and disease mechanisms of some leukodystrophies taken as example for each category. Some leukodystrophies fall into more than one category. Given the complex molecular and cellular interplay underlying white matter pathology, recognition of the cellular pathology behind a disease becomes crucial in addressing possible treatment strategies.
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Affiliation(s)
- Marjo S van der Knaap
- Department of Pediatrics/Child Neurology, VU University Medical Centre, Amsterdam Neuroscience, Amsterdam, The Netherlands
- Department of Functional Genomics, Centre for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, The Netherlands
| | - Marianna Bugiani
- Department of Pediatrics/Child Neurology, VU University Medical Centre, Amsterdam Neuroscience, Amsterdam, The Netherlands.
- Department of Pathology, VU University Medical Centre, Amsterdam Neuroscience, Amsterdam, The Netherlands.
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69
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Verkhratsky A, Zorec R, Parpura V. Stratification of astrocytes in healthy and diseased brain. Brain Pathol 2017; 27:629-644. [PMID: 28805002 PMCID: PMC5599174 DOI: 10.1111/bpa.12537] [Citation(s) in RCA: 157] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 06/03/2017] [Accepted: 06/06/2017] [Indexed: 12/11/2022] Open
Abstract
Astrocytes, a subtype of glial cells, come in variety of forms and functions. However, overarching role of these cell is in the homeostasis of the brain, be that regulation of ions, neurotransmitters, metabolism or neuronal synaptic networks. Loss of homeostasis represents the underlying cause of all brain disorders. Thus, astrocytes are likely involved in most if not all of the brain pathologies. We tabulate astroglial homeostatic functions along with pathological condition that arise from dysfunction of these glial cells. Classification of astrocytes is presented with the emphasis on evolutionary trails, morphological appearance and numerical preponderance. We note that, even though astrocytes from a variety of mammalian species share some common features, human astrocytes appear to be the largest and most complex of all astrocytes studied thus far. It is then an imperative to develop humanized models to study the role of astrocytes in brain pathologies, which is perhaps most abundantly clear in the case of glioblastoma multiforme.
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Affiliation(s)
- Alexei Verkhratsky
- Division of Neuroscience & Experimental PsychologyThe University of ManchesterManchesterUnited Kingdom
- Achúcarro Basque Center for NeuroscienceIKERBASQUE, Basque Foundation for Science48011 BilbaoSpain
- Department of NeuroscienceUniversity of the Basque Country UPV/EHU and CIBERNED48940 LeioaSpain
| | - Robert Zorec
- Laboratory of Cell EngineeringCelica BIOMEDICAL, Tehnološki park 24, Ljubljana 1000SloveniaEurope
- Laboratory of Neuroendocrinology‐Molecular Cell PhysiologyInstitute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, Ljubljana 1000SloveniaEurope
| | - Vladimir Parpura
- Department of Neurobiology, Civitan International Research Center and Center for Glial Biology in Medicine, Evelyn F. McKnight Brain Institute, Atomic Force Microscopy & Nanotechnology Laboratories, 1719 6th Avenue South, CIRC 429University of Alabama at BirminghamBirminghamAL 35294‐0021
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70
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Dai CL, He WB, Du J, Tan YQ, Lu GX, Li W. A case of megalencephalic leukoencephalopathy with subcortical cysts type 1 was identified with a novel compound heterozygous alteration (c.135delC; c.423+2dupT) in China. Clin Case Rep 2017; 5:961-967. [PMID: 28588848 PMCID: PMC5458048 DOI: 10.1002/ccr3.986] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 03/14/2017] [Accepted: 03/19/2017] [Indexed: 11/08/2022] Open
Abstract
We report a compound heterozygous mutation (c.135delC; c.423+2dupT) of MLC1 gene in a Chinese patient underlying infantile macrocephaly and neurological deterioration in early childhood. Brain MRI revealed diffusion abnormality in swollen white matter and a subcortical cyst. The cDNA sequencing analysis for the c.423+2dupT variant revealed skipping of exon 5.
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Affiliation(s)
- Cong-Ling Dai
- Institute of Reproductive and Stem Cell Engineering Central South University Hunan 410008 China
| | - Wen-Bin He
- Institute of Reproductive and Stem Cell Engineering Central South University Hunan 410008 China.,Reproductive and Genetic Hospital of Citic-Xiangya Hunan 410008 China
| | - Juan Du
- Institute of Reproductive and Stem Cell Engineering Central South University Hunan 410008 China.,Reproductive and Genetic Hospital of Citic-Xiangya Hunan 410008 China
| | - Yue-Qiu Tan
- Institute of Reproductive and Stem Cell Engineering Central South University Hunan 410008 China.,Reproductive and Genetic Hospital of Citic-Xiangya Hunan 410008 China
| | - Guang-Xiu Lu
- Institute of Reproductive and Stem Cell Engineering Central South University Hunan 410008 China.,Reproductive and Genetic Hospital of Citic-Xiangya Hunan 410008 China.,National Engineering and Research Center of Human Stem Cells Changsha Hunan 410000 China
| | - Wen Li
- Institute of Reproductive and Stem Cell Engineering Central South University Hunan 410008 China.,Reproductive and Genetic Hospital of Citic-Xiangya Hunan 410008 China
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71
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Bugiani M, Dubey M, Breur M, Postma NL, Dekker MP, Ter Braak T, Boschert U, Abbink TEM, Mansvelder HD, Min R, van Weering JRT, van der Knaap MS. Megalencephalic leukoencephalopathy with cysts: the Glialcam-null mouse model. Ann Clin Transl Neurol 2017; 4:450-465. [PMID: 28695146 PMCID: PMC5497535 DOI: 10.1002/acn3.405] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 02/28/2017] [Accepted: 03/02/2017] [Indexed: 12/23/2022] Open
Abstract
Objective Megalencephalic leukoencephalopathy with cysts (MLC) is a genetic infantile‐onset disease characterized by macrocephaly and white matter edema due to loss of MLC1 function. Recessive mutations in either MLC1 or GLIALCAM cause the disease. MLC1 is involved in astrocytic volume regulation; GlialCAM ensures the correct membrane localization of MLC1. Their exact role in brain ion‐water homeostasis is only partly defined. We characterized Glialcam‐null mice for further studies. Methods We investigated the consequences of loss of GlialCAM in Glialcam‐null mice and compared GlialCAM developmental expression in mice and men. Results Glialcam‐null mice had early‐onset megalencephaly and increased brain water content. From 3 weeks, astrocytes were abnormal with swollen processes abutting blood vessels. Concomitantly, progressive white matter vacuolization developed due to intramyelinic edema. Glialcam‐null astrocytes showed abolished expression of MLC1, reduced expression of the chloride channel ClC‐2 and increased expression and redistribution of the water channel aquaporin4. Expression of other MLC1‐interacting proteins and the volume regulated anion channel LRRC8A was unchanged. In mice, GlialCAM expression increased until 3 weeks and then stabilized. In humans, GlialCAM expression was highest in the first 3 years to then decrease and stabilize from approximately 5 years. Interpretation Glialcam‐null mice replicate the early stages of the human disease with early‐onset intramyelinic edema. The earliest change is astrocytic swelling, further substantiating that a defect in astrocytic volume regulation is the primary cellular defect in MLC. GlialCAM expression affects expression of MLC1, ClC‐2 and aquaporin4, indicating that abnormal interplay between these proteins is a disease mechanism in megalencephalic leukoencephalopathy with cysts.
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Affiliation(s)
- Marianna Bugiani
- Department of Pediatrics/Child Neurology Amsterdam Neuroscience VU University Medical Center Amsterdam The Netherlands.,Department of Pathology Amsterdam Neuroscience VU University Medical Center Amsterdam The Netherlands
| | - Mohit Dubey
- Department of Pediatrics/Child Neurology Amsterdam Neuroscience VU University Medical Center Amsterdam The Netherlands.,Department of Integrative Neurophysiology Center for Neurogenomics and Cognitive Research Amsterdam Neuroscience VU University Amsterdam The Netherlands
| | - Marjolein Breur
- Department of Pediatrics/Child Neurology Amsterdam Neuroscience VU University Medical Center Amsterdam The Netherlands
| | - Nienke L Postma
- Department of Pediatrics/Child Neurology Amsterdam Neuroscience VU University Medical Center Amsterdam The Netherlands
| | - Marien P Dekker
- Department of Functional Genomics Center for Neurogenomics and Cognitive Research Amsterdam Neuroscience VU University Amsterdam The Netherlands
| | - Timo Ter Braak
- Department of Pediatrics/Child Neurology Amsterdam Neuroscience VU University Medical Center Amsterdam The Netherlands
| | - Ursula Boschert
- Translational Innovation Platform Immunology/Neurology EMD Serono Research & Development Institute Billerica 01821 Massachusetts
| | - Truus E M Abbink
- Department of Pediatrics/Child Neurology Amsterdam Neuroscience VU University Medical Center Amsterdam The Netherlands
| | - Huibert D Mansvelder
- Department of Integrative Neurophysiology Center for Neurogenomics and Cognitive Research Amsterdam Neuroscience VU University Amsterdam The Netherlands
| | - Rogier Min
- Department of Pediatrics/Child Neurology Amsterdam Neuroscience VU University Medical Center Amsterdam The Netherlands.,Department of Integrative Neurophysiology Center for Neurogenomics and Cognitive Research Amsterdam Neuroscience VU University Amsterdam The Netherlands
| | - Jan R T van Weering
- Department of Functional Genomics Center for Neurogenomics and Cognitive Research Amsterdam Neuroscience VU University Amsterdam The Netherlands
| | - Marjo S van der Knaap
- Department of Pediatrics/Child Neurology Amsterdam Neuroscience VU University Medical Center Amsterdam The Netherlands.,Department of Functional Genomics Center for Neurogenomics and Cognitive Research Amsterdam Neuroscience VU University Amsterdam The Netherlands
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Sudha D, Kohansal-Nodehi M, Kovuri P, Manda SS, Neriyanuri S, Gopal L, Bhende P, Chidambaram S, Arunachalam JP. Proteomic profiling of human intraschisis cavity fluid. Clin Proteomics 2017; 14:13. [PMID: 28450823 PMCID: PMC5404285 DOI: 10.1186/s12014-017-9148-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 04/07/2017] [Indexed: 12/24/2022] Open
Abstract
Background X-linked retinoschisis (XLRS) is a vitreoretinal degenerative disorder causing vision deterioration, due to structural defects in retina. The hallmark of this disease includes radial streaks arising from the fovea and splitting of inner retinal layers (schisis). Although these retinal changes are attributed to mutations in the retinoschisin gene, schisis is also observed in patients who do not carry mutations. In addition, the origin of intraschisis fluid, the triggering point of schisis formation and its progression are largely unknown still. So far, there is no report on the complete proteomic analysis of this fluid. Schisis fluid proteome could reflect biochemical changes in the disease condition, helping in better understanding and management of retinoschisis. Therefore it was of interest to investigate the intraschisis fluid proteome using high-resolution mass spectrometry. Methods Two male XLRS patients (aged 4 and 40 years) underwent clinical and genetic evaluation followed by surgical extraction of intraschisis fluids. The two fluid samples were resolved on a SDS-PAGE and the processed peptides were analyzed by Q-Exactive plus hybrid quadrupole-Orbitrap mass spectrometry. Functional annotation of the identified proteins was performed using Ingenuity pathway analysis software. Results Mass spectrometry analysis detected 770 nonredundant proteins in the intraschisis fluid. Retinol dehydrogenase 14 was found to be abundant in the schisis fluid. Gene ontology based analysis indicated that 19% of the intraschisis fluid proteins were localized to the extracellular matrix and 15% of the proteins were involved in signal transduction. Functional annotation identified three primary canonical pathways to be associated with the schisis fluid proteome viz., LXR/RXR activation, complement system and acute phase response signalling, which are involved in immune and inflammatory responses. Collectively, our results show that intraschisis fluid comprises specific inflammatory proteins which highly reflect the disease environment. Conclusion Based on our study, it is suggested that inflammation might play a key role in the pathogenesis of XLRS. To our knowledge, this is the first report describing the complete proteome of intraschisis fluid, which could serve as a template for future research and facilitate the development of therapeutic modalities for XLRS. Electronic supplementary material The online version of this article (doi:10.1186/s12014-017-9148-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Dhandayuthapani Sudha
- SN ONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Chennai, India.,School of Biotechnology, SASTRA University, Thanjavur, India
| | | | - Purnima Kovuri
- Department of Biochemistry and Molecular Biology, Pondicherry University, Puducherry, India
| | | | - Srividya Neriyanuri
- Elite School of Optometry, Unit of Medical Research Foundation, Chennai, India
| | - Lingam Gopal
- Shri Bhagwan Mahavir Vitreo-Retinal Services, Medical Research Foundation, Chennai, India
| | - Pramod Bhende
- Shri Bhagwan Mahavir Vitreo-Retinal Services, Medical Research Foundation, Chennai, India
| | | | - Jayamuruga Pandian Arunachalam
- SN ONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Chennai, India.,Central Inter-Disciplinary Research Facility (CIDRF), Sri Balaji Vidyapeeth Medical University, Mahatma Gandhi Medical College and Research Institute Campus, Puducherry, India
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73
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Sirisi S, Elorza-Vidal X, Arnedo T, Armand-Ugón M, Callejo G, Capdevila-Nortes X, López-Hernández T, Schulte U, Barrallo-Gimeno A, Nunes V, Gasull X, Estévez R. Depolarization causes the formation of a ternary complex between GlialCAM, MLC1 and ClC-2 in astrocytes: implications in megalencephalic leukoencephalopathy. Hum Mol Genet 2017; 26:2436-2450. [DOI: 10.1093/hmg/ddx134] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 03/29/2017] [Indexed: 01/06/2023] Open
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74
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Poroca DR, Pelis RM, Chappe VM. ClC Channels and Transporters: Structure, Physiological Functions, and Implications in Human Chloride Channelopathies. Front Pharmacol 2017; 8:151. [PMID: 28386229 PMCID: PMC5362633 DOI: 10.3389/fphar.2017.00151] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 03/09/2017] [Indexed: 02/04/2023] Open
Abstract
The discovery of ClC proteins at the beginning of the 1990s was important for the development of the Cl- transport research field. ClCs form a large family of proteins that mediate voltage-dependent transport of Cl- ions across cell membranes. They are expressed in both plasma and intracellular membranes of cells from almost all living organisms. ClC proteins form transmembrane dimers, in which each monomer displays independent ion conductance. Eukaryotic members also possess a large cytoplasmic domain containing two CBS domains, which are involved in transport modulation. ClC proteins function as either Cl- channels or Cl-/H+ exchangers, although all ClC proteins share the same basic architecture. ClC channels have two gating mechanisms: a relatively well-studied fast gating mechanism, and a slow gating mechanism, which is poorly defined. ClCs are involved in a wide range of physiological processes, including regulation of resting membrane potential in skeletal muscle, facilitation of transepithelial Cl- reabsorption in kidneys, and control of pH and Cl- concentration in intracellular compartments through coupled Cl-/H+ exchange mechanisms. Several inherited diseases result from C1C gene mutations, including myotonia congenita, Bartter's syndrome (types 3 and 4), Dent's disease, osteopetrosis, retinal degeneration, and lysosomal storage diseases. This review summarizes general features, known or suspected, of ClC structure, gating and physiological functions. We also discuss biophysical properties of mammalian ClCs that are directly involved in the pathophysiology of several human inherited disorders, or that induce interesting phenotypes in animal models.
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Affiliation(s)
- Diogo R Poroca
- Department of Physiology and Biophysics, Dalhousie University, Halifax NS, Canada
| | - Ryan M Pelis
- Department of Pharmacology, Dalhousie University, Halifax NS, Canada
| | - Valérie M Chappe
- Department of Physiology and Biophysics, Dalhousie University, Halifax NS, Canada
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75
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Wu M, Moh MC, Schwarz H. HepaCAM associates with connexin 43 and enhances its localization in cellular junctions. Sci Rep 2016; 6:36218. [PMID: 27819278 PMCID: PMC5098153 DOI: 10.1038/srep36218] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 10/12/2016] [Indexed: 12/30/2022] Open
Abstract
HepaCAM (GlialCAM) is frequently deleted in carcinomas, and reintroduction of hepaCAM into transformed cell lines reduces cellular growth and induces senescence. Mutations in HEPACAM give rise to the neurodegenerative disease megalencephalic leukoencephalopathy with subcortical cysts (MLC) since mutated hepaCAM prevents shuttling of MLC1 protein to astrocytic junctions in the plasma membrane. Here we identify that hepaCAM associates with connexin 43, a main component of gap junctions, and enhances connexin 43 localization to the plasma membrane at cellular junctions. HepaCAM also increases the levels of connexin 43, not by enhancing its transcription but by stabilizing connexin 43 protein. In the absence of hepaCAM, connexin 43 undergoes a faster degradation via the lysosomal pathway while proteasomal degradation seems not to be involved. Mutations in hepaCAM that cause MLC, or neutralization of hepaCAM by antibodies disrupt its association with connexin 43 at cellular junctions. By discovering the requirement of hepaCAM for localizing connexin 43, a well-established tumor suppressor, to cellular junctions and stabilizing it there, this study suggests a mechanism by which deletion of hepaCAM may support tumor progression.
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Affiliation(s)
- Meihui Wu
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597.,Immunology Programme, Life Sciences Institute, National University of Singapore, Singapore 117456
| | - Mei Chung Moh
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597.,Immunology Programme, Life Sciences Institute, National University of Singapore, Singapore 117456
| | - Herbert Schwarz
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597.,Immunology Programme, Life Sciences Institute, National University of Singapore, Singapore 117456
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Sugio S, Tohyama K, Oku S, Fujiyoshi K, Yoshimura T, Hikishima K, Yano R, Fukuda T, Nakamura M, Okano H, Watanabe M, Fukata M, Ikenaka K, Tanaka KF. Astrocyte-mediated infantile-onset leukoencephalopathy mouse model. Glia 2016; 65:150-168. [DOI: 10.1002/glia.23084] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 09/22/2016] [Accepted: 09/29/2016] [Indexed: 01/09/2023]
Affiliation(s)
- Shouta Sugio
- Division of Neurobiology and Bioinformatics; National Institute for Physiological Sciences; Okazaki 444-8787 Japan
- Department of Physiological Sciences, School of Life Science; SOKENDAI (The Graduate University for Advanced Studies); Okazaki 444-8787 Japan
| | - Koujiro Tohyama
- Department of Physiology School of Dentistry, The Center of EM and Bio-Imaging Research, Nano-Neuroanatomy; Iwate Medical University; Morioka 020-8505 Japan
| | - Shinichiro Oku
- Division of Membrane Physiology, National Institute for Physiological Sciences; Okazaki 444-8787 Japan
| | - Kanehiro Fujiyoshi
- Department of Orthopedic Surgery; Keio University School of Medicine; Tokyo 160-8582 Japan
- Department of Orthopedic Surgery; National Hospital Organization, Murayama Medical Center; Tokyo 208-0011 Japan
| | - Takeshi Yoshimura
- Division of Neurobiology and Bioinformatics; National Institute for Physiological Sciences; Okazaki 444-8787 Japan
- Department of Physiological Sciences, School of Life Science; SOKENDAI (The Graduate University for Advanced Studies); Okazaki 444-8787 Japan
| | - Keigo Hikishima
- Department of Physiology; Keio University School of Medicine; Tokyo 160-8582 Japan
- Central Institute for Experimental Animals; Kawasaki 210-0821 Japan
| | - Ryutaro Yano
- Department of Physiology; Keio University School of Medicine; Tokyo 160-8582 Japan
| | - Takahiro Fukuda
- Division of Neuropathology, Department of Pathology; The Jikei University School of Medicine; Tokyo 105-8461 Japan
| | - Masaya Nakamura
- Department of Orthopedic Surgery; Keio University School of Medicine; Tokyo 160-8582 Japan
| | - Hideyuki Okano
- Department of Physiology; Keio University School of Medicine; Tokyo 160-8582 Japan
| | - Masahiko Watanabe
- Department of Anatomy; Hokkaido University Graduate School of Medicine; Sapporo 060-8638 Japan
| | - Masaki Fukata
- Department of Physiological Sciences, School of Life Science; SOKENDAI (The Graduate University for Advanced Studies); Okazaki 444-8787 Japan
- Division of Membrane Physiology, National Institute for Physiological Sciences; Okazaki 444-8787 Japan
| | - Kazuhiro Ikenaka
- Division of Neurobiology and Bioinformatics; National Institute for Physiological Sciences; Okazaki 444-8787 Japan
- Department of Physiological Sciences, School of Life Science; SOKENDAI (The Graduate University for Advanced Studies); Okazaki 444-8787 Japan
| | - Kenji F. Tanaka
- Division of Neurobiology and Bioinformatics; National Institute for Physiological Sciences; Okazaki 444-8787 Japan
- Department of Neuropsychiatry; Keio University School of Medicine; Tokyo 160-8582 Japan
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Abdel-Salam GMH, Abdel-Hamid MS, Ismail SI, Hosny H, Omar T, Effat L, Aglan MS, Temtamy SA, Zaki MS. Megalencephalic leukoencephalopathy with cysts in twelve Egyptian patients: novel mutations in MLC1 and HEPACAM and a founder effect. Metab Brain Dis 2016; 31:1171-9. [PMID: 27389245 DOI: 10.1007/s11011-016-9861-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 06/19/2016] [Indexed: 11/25/2022]
Abstract
Two genes causing megalencephalic leukoencephalopathy with subcortical cysts (MLC) have been discovered so far. Here, we identified MLC1 and HEPACAM mutations in ten and two patients, respectively. The molecular results included an unreported inframe duplication mutation (c.929_930dupCTGCTG; p.L309dup) of MLC1 and a novel missense mutation c.293G>A (p.R98H) of HEPACAM. Further, the previously reported missense (c.278C>T; p.S93L) and the deletion/insertion (c.908_918delinsGCA; p.V303Gfs*96) were found in one and 8 patients (75 %), respectively. The 8 patients carrying the p.V303Gfs*96 shared a similar haplotype suggesting a founder effect. All mutations were in the homozygous state proving the autosomal recessive mode of inheritance. The core phenotype of macrocephaly, subcortical cysts and white matter appeared homogeneous although the patients differed in the onset, clinical course, disease severity and brain imaging findings. Our study expands the spectrum of mutations in MLC1 and HEPACAM and supports the genetic and clinical heterogeneity. Further, It confirms c.908_918delinsGCA (p.V303Gfs*96) as a founder mutation among Egyptian patients. This finding will contribute to provide targeted testing for this mutation in MLC patients in our population.
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Affiliation(s)
- Ghada M H Abdel-Salam
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Tahrir street, Dokki, Cairo, Egypt.
- Centre of Excellence for Human Genetics, National Research Centre, Cairo, Egypt.
| | - Mohamed S Abdel-Hamid
- Centre of Excellence for Human Genetics, National Research Centre, Cairo, Egypt
- Medical Molecular Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo, Egypt
| | - Samira I Ismail
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Tahrir street, Dokki, Cairo, Egypt
- Centre of Excellence for Human Genetics, National Research Centre, Cairo, Egypt
| | - Heba Hosny
- National Institute of Neuromotor system, Cairo, Egypt
| | - Tarek Omar
- Department of Pediatrics, Alexandria University, Alexandria, Egypt
| | - Laila Effat
- Centre of Excellence for Human Genetics, National Research Centre, Cairo, Egypt
- Medical Molecular Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo, Egypt
| | - Mona S Aglan
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Tahrir street, Dokki, Cairo, Egypt
- Centre of Excellence for Human Genetics, National Research Centre, Cairo, Egypt
| | - Samia A Temtamy
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Tahrir street, Dokki, Cairo, Egypt
- Centre of Excellence for Human Genetics, National Research Centre, Cairo, Egypt
| | - Maha S Zaki
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Tahrir street, Dokki, Cairo, Egypt
- Centre of Excellence for Human Genetics, National Research Centre, Cairo, Egypt
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Scholz C, Steinemann D, Mälzer M, Roy M, Arslan-Kirchner M, Illig T, Schmidtke J, Stuhrmann M. NCAM2 deletion in a boy with macrocephaly and autism: Cause, association or predisposition? Eur J Med Genet 2016; 59:493-8. [PMID: 27596683 DOI: 10.1016/j.ejmg.2016.08.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 08/10/2016] [Accepted: 08/15/2016] [Indexed: 12/28/2022]
Abstract
UNLABELLED We report on an 8-year-old boy with autism spectrum disorder (ASD), speech delay, behavioural problems, disturbed sleep and macrosomia including macrocephaly carrying a microdeletion that contains the entire NCAM2 gene and no other functional genes. Other family members with the microdeletion show a large skull circumference but do not exhibit any symptoms of autism spectrum disorder. Among many ASD-candidate genes, NCAM2 has been assumed to play a pivotal role in the development of ASD because of its function in the outgrowth and bundling of neurites. Our reported case raises the questions whether the NCAM2-deletion is the true cause of the ASD or only a risk factor and whether there might be any connection in NCAM2 with skull-size KEY WORDS autism spectrum disorder, macrocephaly, neural cell adhesion molecule 2 protein (NCAM2), array comparative genomic hybridization (microarray).
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Affiliation(s)
- Caroline Scholz
- Institute of Human Genetics, Hannover Medical School, Hannover, Germany.
| | - Doris Steinemann
- Institute of Human Genetics, Hannover Medical School, Hannover, Germany
| | - Madeleine Mälzer
- Institute of Human Genetics, Hannover Medical School, Hannover, Germany
| | - Mandy Roy
- Psychiatric Clinic, Hannover Medical School, Hannover, Germany
| | | | - Thomas Illig
- Institute of Human Genetics, Hannover Medical School, Hannover, Germany; Hannover Unified Biobank, Germany
| | - Jörg Schmidtke
- Institute of Human Genetics, Hannover Medical School, Hannover, Germany
| | - Manfred Stuhrmann
- Institute of Human Genetics, Hannover Medical School, Hannover, Germany
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Miyata M, Mandai K, Maruo T, Sato J, Shiotani H, Kaito A, Itoh Y, Wang S, Fujiwara T, Mizoguchi A, Takai Y, Rikitake Y. Localization of nectin-2δ at perivascular astrocytic endfoot processes and degeneration of astrocytes and neurons in nectin-2 knockout mouse brain. Brain Res 2016; 1649:90-101. [PMID: 27545667 DOI: 10.1016/j.brainres.2016.08.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Revised: 08/09/2016] [Accepted: 08/18/2016] [Indexed: 10/21/2022]
Abstract
Nectins are Ca2+-independent immunoglobulin-like cell-cell adhesion molecules. In the nervous system, among four members (nectin-1, -2, -3, and -4), nectin-1 and -3 are asymmetrically localized at puncta adherentia junctions formed between the mossy fiber terminals and the dendrites of CA3 pyramidal neurons in the mouse hippocampus and heterophilic trans-interactions between nectin-1 and nectin-3 are involved in the selective interaction of axons and dendrites of cultured neurons. By contrast, nectin-2, which has two splicing variants, nectin-2α and -2δ, has not been well characterized in the brain. We showed here that nectin-2α was expressed in both cultured mouse neurons and astrocytes whereas nectin-2δ was selectively expressed in the astrocytes. Nectin-2δ was localized at the adhesion sites between adjacent cultured astrocytes, but in the brain it was localized on the plasma membranes of astrocytic perivascular endfoot processes facing the basement membrane of blood vessels. Genetic ablation of nectin-2 caused degeneration of astrocytic perivascular endfoot processes and neurons in the cerebral cortex. These results uncovered for the first time the localization and critical functions of nectin-2 in the brain.
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Affiliation(s)
- Muneaki Miyata
- Division of Signal Transduction, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan; Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0047, Japan
| | - Kenji Mandai
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0047, Japan; CREST, Japan Science and Technology Agency, Kobe, Japan
| | - Tomohiko Maruo
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0047, Japan; CREST, Japan Science and Technology Agency, Kobe, Japan
| | - Junya Sato
- Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Hajime Shiotani
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0047, Japan; Department of Neurology, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Aika Kaito
- CREST, Japan Science and Technology Agency, Kobe, Japan; Department of Neural Regeneration and Cell Communication, Mie University Graduate School of Medicine, Tsu 514-8507, Japan
| | - Yu Itoh
- CREST, Japan Science and Technology Agency, Kobe, Japan; Department of Neural Regeneration and Cell Communication, Mie University Graduate School of Medicine, Tsu 514-8507, Japan
| | - Shujie Wang
- CREST, Japan Science and Technology Agency, Kobe, Japan; Department of Neural Regeneration and Cell Communication, Mie University Graduate School of Medicine, Tsu 514-8507, Japan
| | - Takeshi Fujiwara
- CREST, Japan Science and Technology Agency, Kobe, Japan; Department of Neural Regeneration and Cell Communication, Mie University Graduate School of Medicine, Tsu 514-8507, Japan
| | - Akira Mizoguchi
- CREST, Japan Science and Technology Agency, Kobe, Japan; Department of Neural Regeneration and Cell Communication, Mie University Graduate School of Medicine, Tsu 514-8507, Japan
| | - Yoshimi Takai
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0047, Japan; CREST, Japan Science and Technology Agency, Kobe, Japan.
| | - Yoshiyuki Rikitake
- Division of Signal Transduction, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan; CREST, Japan Science and Technology Agency, Kobe, Japan; Department of Medical Pharmaceutics, Kobe Pharmaceutical University, Kobe 658-8558, Japan.
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Cao B, Yan H, Guo M, Xie H, Wu Y, Gu Q, Xiao J, Shang J, Yang Y, Xiong H, Niu Z, Wu X, Jiang Y, Wang J. Ten Novel Mutations in Chinese Patients with Megalencephalic Leukoencephalopathy with Subcortical Cysts and a Long-Term Follow-Up Research. PLoS One 2016; 11:e0157258. [PMID: 27322623 PMCID: PMC4913951 DOI: 10.1371/journal.pone.0157258] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 05/26/2016] [Indexed: 11/21/2022] Open
Abstract
Objective Megalencephalic leukoencephalopathy with subcortical cysts (MLC, OMIM 604004) is a rare neurological deterioration disease. We aimed to clarify clinical and genetic features of Chinese MLC patients. Methods Clinical information and peripheral venous blood of 20 patients and their families were collected, Sanger-sequencing and Multiple Ligation-dependent Probe Amplification were performed to make genetic analysis. Splicing-site mutation was confirmed with RT-PCR. UPD was detected by haplotype analysis. Follow-up study was performed through telephone for 27 patients. Results Out of 20 patients, macrocephaly, classic MRI features, motor development delay and cognitive impairment were detected in 20(100%), 20(100%), 17(85%) and 4(20%) patients, respectively. 20(100%) were clinically diagnosed with MLC. 19(95%) were genetically diagnosed with 10 novel mutations in MLC1, MLC1 and GlialCAM mutations were identified in 15 and 4 patients, respectively. Deletion mutation from exon4 to exon9 and a homozygous point mutation due to maternal UPD of chromosome22 in MLC1 were found firstly. c.598-2A>C in MLC1 leads to the skip of exon8. c.772-1G>C in MLC1 accounting for 15.5%(9/58) alleles in Chinese patients might be a founder or a hot-spot mutation. Out of 27 patients in the follow-up study, head circumference was ranged from 56cm to 61cm in patients older than 5yeas old, with a median of 57cm. Motor development delay and cognitive impairment were detected in 22(81.5%) and 5(18.5%) patients, respectively. Motor and cognitive deterioration was found in 5 (18.5%) and 2 patients (7.4%), respectively. Improvements and MRI recovery were first found in Chinese patients. Rate of seizures (45.5%), transient motor retrogress (45.5%) and unconsciousness (13.6%) after head trauma was much higher than that after fever (18.2%, 9.1%, 0%, respectively). Significance It’s a clinical and genetic analysis and a follow-up study for largest sample of Chinese MLC patients, identifying 10 novel mutations, expanding mutation spectrums and discovering clinical features of Chinese MLC patients.
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Affiliation(s)
- Binbin Cao
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Huifang Yan
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Mangmang Guo
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
- Department of Pediatrics, Beijing Tian Tan Hospital, Capital Medical University Beijing 100050, China
| | - Han Xie
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Ye Wu
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Qiang Gu
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Jiangxi Xiao
- Department of Radiology, Peking University First Hospital, Beijing 100034, China
| | - Jing Shang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
- Department of Neurology, Shanxi Dayi Hospital, Taiyuan 030000, Shanxi Province, China
| | - Yanling Yang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Hui Xiong
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Zhengping Niu
- Department of Neurology, First Hospital of Shanxi Medical University, Taiyuan 030001, Shanxi Province, China
| | - Xiru Wu
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Yuwu Jiang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
- * E-mail: (YWJ); (JMW)
| | - Jingmin Wang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
- * E-mail: (YWJ); (JMW)
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Barrallo-Gimeno A, Gradogna A, Zanardi I, Pusch M, Estévez R. Regulatory-auxiliary subunits of CLC chloride channel-transport proteins. J Physiol 2016; 593:4111-27. [PMID: 25762128 DOI: 10.1113/jp270057] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 02/15/2015] [Indexed: 02/06/2023] Open
Abstract
The CLC family of chloride channels and transporters is composed by nine members, but only three of them, ClC-Ka/b, ClC-7 and ClC-2, have been found so far associated with auxiliary subunits. These CLC regulatory subunits are small proteins that present few common characteristics among them, both structurally and functionally, and their effects on the corresponding CLC protein are different. Barttin, a protein with two transmembrane domains, is essential for the membrane localization of ClC-K proteins and their activity in the kidney and inner ear. Ostm1 is a protein with a single transmembrane domain and a highly glycosylated N-terminus. Unlike the other two CLC auxiliary subunits, Ostm1 shows a reciprocal relationship with ClC-7 for their stability. The subcellular localization of Ostm1 depends on ClC-7 and not the other way around. ClC-2 is active on its own, but GlialCAM, a transmembrane cell adhesion molecule with two extracellular immunoglobulin (Ig)-like domains, regulates its subcellular localization and activity in glial cells. The common theme for these three proteins is their requirement for a proper homeostasis, since their malfunction leads to distinct diseases. We will review here their properties and their role in normal chloride physiology and the pathological consequences of their improper function.
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Affiliation(s)
- Alejandro Barrallo-Gimeno
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II, University of Barcelona, Barcelona, Spain.,U-750, Centro de investigación en red de enfermedades raras (CIBERER), ISCIII, Barcelona, Spain
| | | | - Ilaria Zanardi
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genoa, Italy
| | - Michael Pusch
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genoa, Italy
| | - Raúl Estévez
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II, University of Barcelona, Barcelona, Spain.,U-750, Centro de investigación en red de enfermedades raras (CIBERER), ISCIII, Barcelona, Spain
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Imbrici P, Liantonio A, Camerino GM, De Bellis M, Camerino C, Mele A, Giustino A, Pierno S, De Luca A, Tricarico D, Desaphy JF, Conte D. Therapeutic Approaches to Genetic Ion Channelopathies and Perspectives in Drug Discovery. Front Pharmacol 2016; 7:121. [PMID: 27242528 PMCID: PMC4861771 DOI: 10.3389/fphar.2016.00121] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Accepted: 04/25/2016] [Indexed: 12/21/2022] Open
Abstract
In the human genome more than 400 genes encode ion channels, which are transmembrane proteins mediating ion fluxes across membranes. Being expressed in all cell types, they are involved in almost all physiological processes, including sense perception, neurotransmission, muscle contraction, secretion, immune response, cell proliferation, and differentiation. Due to the widespread tissue distribution of ion channels and their physiological functions, mutations in genes encoding ion channel subunits, or their interacting proteins, are responsible for inherited ion channelopathies. These diseases can range from common to very rare disorders and their severity can be mild, disabling, or life-threatening. In spite of this, ion channels are the primary target of only about 5% of the marketed drugs suggesting their potential in drug discovery. The current review summarizes the therapeutic management of the principal ion channelopathies of central and peripheral nervous system, heart, kidney, bone, skeletal muscle and pancreas, resulting from mutations in calcium, sodium, potassium, and chloride ion channels. For most channelopathies the therapy is mainly empirical and symptomatic, often limited by lack of efficacy and tolerability for a significant number of patients. Other channelopathies can exploit ion channel targeted drugs, such as marketed sodium channel blockers. Developing new and more specific therapeutic approaches is therefore required. To this aim, a major advancement in the pharmacotherapy of channelopathies has been the discovery that ion channel mutations lead to change in biophysics that can in turn specifically modify the sensitivity to drugs: this opens the way to a pharmacogenetics strategy, allowing the development of a personalized therapy with increased efficacy and reduced side effects. In addition, the identification of disease modifiers in ion channelopathies appears an alternative strategy to discover novel druggable targets.
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Affiliation(s)
- Paola Imbrici
- Department of Pharmacy - Drug Sciences, University of Bari "Aldo Moro" Bari, Italy
| | - Antonella Liantonio
- Department of Pharmacy - Drug Sciences, University of Bari "Aldo Moro" Bari, Italy
| | - Giulia M Camerino
- Department of Pharmacy - Drug Sciences, University of Bari "Aldo Moro" Bari, Italy
| | - Michela De Bellis
- Department of Pharmacy - Drug Sciences, University of Bari "Aldo Moro" Bari, Italy
| | - Claudia Camerino
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari "Aldo Moro" Bari, Italy
| | - Antonietta Mele
- Department of Pharmacy - Drug Sciences, University of Bari "Aldo Moro" Bari, Italy
| | - Arcangela Giustino
- Department of Biomedical Sciences and Human Oncology, University of Bari "Aldo Moro" Bari, Italy
| | - Sabata Pierno
- Department of Pharmacy - Drug Sciences, University of Bari "Aldo Moro" Bari, Italy
| | - Annamaria De Luca
- Department of Pharmacy - Drug Sciences, University of Bari "Aldo Moro" Bari, Italy
| | - Domenico Tricarico
- Department of Pharmacy - Drug Sciences, University of Bari "Aldo Moro" Bari, Italy
| | - Jean-Francois Desaphy
- Department of Biomedical Sciences and Human Oncology, University of Bari "Aldo Moro" Bari, Italy
| | - Diana Conte
- Department of Pharmacy - Drug Sciences, University of Bari "Aldo Moro" Bari, Italy
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Abstract
Background Jacobsen syndrome (JBS) is a contiguous gene deletion syndrome involving 11q terminal deletion. Interstitial deletions at distal 11q are rare and their contributions to the clinical phenotype of JBS are unknown. Case presentation We presented the chromosome microarray (CMA) data and the clinical features of two individuals carrying a non-overlapping de novo deletion each at the 11q23.3-q24.2 region in an effort to analyze the correlation between region of deletion at 11q and phenotype. Both deletions are likely pathogenic for patient’s condition. The deletion at 11q23.3q24.1 is associated with short stature, relative microcephaly, failure to thrive, hypotonia and sleeping disorder. The deletion at 11q24.2 involves HEPACAM and our patient’s clinical presentation (relative macrocephaly, abnormal MRI, mild developmental delay and seizure) is not inconsistent with Megalencephalic leukoencephalopathy with subcortical cysts 2B. Conclusions Our finds support the notion that more than one critical region at 11q23.3-qter are responsible for the variable clinical presentation of JBS, thus JBS is a true contiguous gene deletion syndrome where multiple loci contributed to the clinical characteristics of JBS. Small interstitial deletions at 11q23.3-q24.2 and their associated unique features also suggest emerging novel genomic disorders. Electronic supplementary material The online version of this article (doi:10.1186/s13039-016-0247-7) contains supplementary material, which is available to authorized users.
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Lanciotti A, Brignone MS, Visentin S, De Nuccio C, Catacuzzeno L, Mallozzi C, Petrini S, Caramia M, Veroni C, Minnone G, Bernardo A, Franciolini F, Pessia M, Bertini E, Petrucci TC, Ambrosini E. Megalencephalic leukoencephalopathy with subcortical cysts protein-1 regulates epidermal growth factor receptor signaling in astrocytes. Hum Mol Genet 2016; 25:1543-58. [DOI: 10.1093/hmg/ddw032] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 02/03/2016] [Indexed: 01/13/2023] Open
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Heckel T, Schmucki R, Berrera M, Ringshandl S, Badi L, Steiner G, Ravon M, Küng E, Kuhn B, Kratochwil NA, Schmitt G, Kiialainen A, Nowaczyk C, Daff H, Khan AP, Lekolool I, Pelle R, Okoth E, Bishop R, Daubenberger C, Ebeling M, Certa U. Functional analysis and transcriptional output of the Göttingen minipig genome. BMC Genomics 2015; 16:932. [PMID: 26573612 PMCID: PMC4647470 DOI: 10.1186/s12864-015-2119-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 10/20/2015] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND In the past decade the Göttingen minipig has gained increasing recognition as animal model in pharmaceutical and safety research because it recapitulates many aspects of human physiology and metabolism. Genome-based comparison of drug targets together with quantitative tissue expression analysis allows rational prediction of pharmacology and cross-reactivity of human drugs in animal models thereby improving drug attrition which is an important challenge in the process of drug development. RESULTS Here we present a new chromosome level based version of the Göttingen minipig genome together with a comparative transcriptional analysis of tissues with pharmaceutical relevance as basis for translational research. We relied on mapping and assembly of WGS (whole-genome-shotgun sequencing) derived reads to the reference genome of the Duroc pig and predict 19,228 human orthologous protein-coding genes. Genome-based prediction of the sequence of human drug targets enables the prediction of drug cross-reactivity based on conservation of binding sites. We further support the finding that the genome of Sus scrofa contains about ten-times less pseudogenized genes compared to other vertebrates. Among the functional human orthologs of these minipig pseudogenes we found HEPN1, a putative tumor suppressor gene. The genomes of Sus scrofa, the Tibetan boar, the African Bushpig, and the Warthog show sequence conservation of all inactivating HEPN1 mutations suggesting disruption before the evolutionary split of these pig species. We identify 133 Sus scrofa specific, conserved long non-coding RNAs (lncRNAs) in the minipig genome and show that these transcripts are highly conserved in the African pigs and the Tibetan boar suggesting functional significance. Using a new minipig specific microarray we show high conservation of gene expression signatures in 13 tissues with biomedical relevance between humans and adult minipigs. We underline this relationship for minipig and human liver where we could demonstrate similar expression levels for most phase I drug-metabolizing enzymes. Higher expression levels and metabolic activities were found for FMO1, AKR/CRs and for phase II drug metabolizing enzymes in minipig as compared to human. The variability of gene expression in equivalent human and minipig tissues is considerably higher in minipig organs, which is important for study design in case a human target belongs to this variable category in the minipig. The first analysis of gene expression in multiple tissues during development from young to adult shows that the majority of transcriptional programs are concluded four weeks after birth. This finding is in line with the advanced state of human postnatal organ development at comparative age categories and further supports the minipig as model for pediatric drug safety studies. CONCLUSIONS Genome based assessment of sequence conservation combined with gene expression data in several tissues improves the translational value of the minipig for human drug development. The genome and gene expression data presented here are important resources for researchers using the minipig as model for biomedical research or commercial breeding. Potential impact of our data for comparative genomics, translational research, and experimental medicine are discussed.
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Affiliation(s)
- Tobias Heckel
- Roche Pharmaceutical Research and Early Development (pRED), Roche Innovation Center Basel, Grenzacherstrasse 124, 4070, Basel, Switzerland.
| | - Roland Schmucki
- Roche Pharmaceutical Research and Early Development (pRED), Roche Innovation Center Basel, Grenzacherstrasse 124, 4070, Basel, Switzerland.
| | - Marco Berrera
- Roche Pharmaceutical Research and Early Development (pRED), Roche Innovation Center Basel, Grenzacherstrasse 124, 4070, Basel, Switzerland.
| | - Stephan Ringshandl
- Roche Pharmaceutical Research and Early Development (pRED), Roche Innovation Center Basel, Grenzacherstrasse 124, 4070, Basel, Switzerland.
| | - Laura Badi
- Roche Pharmaceutical Research and Early Development (pRED), Roche Innovation Center Basel, Grenzacherstrasse 124, 4070, Basel, Switzerland.
| | - Guido Steiner
- Roche Pharmaceutical Research and Early Development (pRED), Roche Innovation Center Basel, Grenzacherstrasse 124, 4070, Basel, Switzerland.
| | - Morgane Ravon
- Roche Pharmaceutical Research and Early Development (pRED), Roche Innovation Center Basel, Grenzacherstrasse 124, 4070, Basel, Switzerland.
| | - Erich Küng
- Roche Pharmaceutical Research and Early Development (pRED), Roche Innovation Center Basel, Grenzacherstrasse 124, 4070, Basel, Switzerland.
| | - Bernd Kuhn
- Roche Pharmaceutical Research and Early Development (pRED), Roche Innovation Center Basel, Grenzacherstrasse 124, 4070, Basel, Switzerland.
| | - Nicole A Kratochwil
- Roche Pharmaceutical Research and Early Development (pRED), Roche Innovation Center Basel, Grenzacherstrasse 124, 4070, Basel, Switzerland.
| | - Georg Schmitt
- Roche Pharmaceutical Research and Early Development (pRED), Roche Innovation Center Basel, Grenzacherstrasse 124, 4070, Basel, Switzerland.
| | - Anna Kiialainen
- Roche Pharmaceutical Research and Early Development (pRED), Roche Innovation Center Basel, Grenzacherstrasse 124, 4070, Basel, Switzerland.
| | - Corinne Nowaczyk
- Roche Pharmaceutical Research and Early Development (pRED), Roche Innovation Center Basel, Grenzacherstrasse 124, 4070, Basel, Switzerland.
| | - Hamina Daff
- Roche Pharmaceutical Research and Early Development (pRED), Roche Innovation Center Basel, Grenzacherstrasse 124, 4070, Basel, Switzerland.
| | - Azinwi Phina Khan
- Roche Pharmaceutical Research and Early Development (pRED), Roche Innovation Center Basel, Grenzacherstrasse 124, 4070, Basel, Switzerland.
| | - Isaac Lekolool
- International Livestock Research Institute (ILRI), PO Box 30709, Nairobi, 00100, Kenya.
| | - Roger Pelle
- International Livestock Research Institute (ILRI), PO Box 30709, Nairobi, 00100, Kenya.
| | - Edward Okoth
- International Livestock Research Institute (ILRI), PO Box 30709, Nairobi, 00100, Kenya.
| | - Richard Bishop
- International Livestock Research Institute (ILRI), PO Box 30709, Nairobi, 00100, Kenya.
| | - Claudia Daubenberger
- Swiss Tropical and Public Health Institute (Swiss TPH), Socinstr. 57, CH 4002, Basel, Switzerland.
| | - Martin Ebeling
- Roche Pharmaceutical Research and Early Development (pRED), Roche Innovation Center Basel, Grenzacherstrasse 124, 4070, Basel, Switzerland.
| | - Ulrich Certa
- Roche Pharmaceutical Research and Early Development (pRED), Roche Innovation Center Basel, Grenzacherstrasse 124, 4070, Basel, Switzerland.
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Dash PK, Raj DH, Sahu H. Megalencephalic leucoencephalopathy with subcortical cysts: subcortical diffuse leucoencephalopathy associated with white matter cystic degeneration. BMJ Case Rep 2015; 2015:bcr-2015-211921. [PMID: 26392452 DOI: 10.1136/bcr-2015-211921] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Megalencephalic leucoencephalopathy with subcortical cysts (MLC) is a diffuse subcortical leucoencephalopathy with cystic white matter degeneration. Patients with MLC present with macrocephaly at the first year of life, and neurological abnormalities such as motor deterioration, ataxia, spasticity and cognitive defects progress later. MLC is caused by mutations in the gene MLC1, which encodes a novel protein, MLC1. There is no specific treatment for MLC. Management is based on physiotherapy procedures, psychomotor stimulation and treatment of seizures. We report a case of a 1-year-old boy with a normal birth and developmental history, presenting with progressive increase of head size; on further evaluation with CT and MRI of the brain, the child was diagnosed as MLC.
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Affiliation(s)
- Prafulla Kumar Dash
- Department of Radiodiagnosis, CMIIL-SCB Medical MRI Centre, Cuttack, Odisha, India
| | - Dinesh Harvey Raj
- Department of Radiodiagnosis, SCB Medical College, Cuttack, Odisha, India
| | - Hrushikesh Sahu
- Department of Radiodiagnosis, SCB Medical College, Cuttack, Odisha, India
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Jeworutzki E, Lagostena L, Elorza-Vidal X, López-Hernández T, Estévez R, Pusch M. GlialCAM, a CLC-2 Cl(-) channel subunit, activates the slow gate of CLC chloride channels. Biophys J 2015; 107:1105-1116. [PMID: 25185546 PMCID: PMC4156679 DOI: 10.1016/j.bpj.2014.07.040] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 07/18/2014] [Accepted: 07/25/2014] [Indexed: 01/17/2023] Open
Abstract
GlialCAM, a glial cell adhesion molecule mutated in megalencephalic leukoencephalopathy with subcortical cysts, targets the CLC-2 Cl(-) channel to cell contacts in glia and activates CLC-2 currents in vitro and in vivo. We found that GlialCAM clusters all CLC channels at cell contacts in vitro and thus studied GlialCAM interaction with CLC channels to investigate the mechanism of functional activation. GlialCAM slowed deactivation kinetics of CLC-Ka/barttin channels and increased CLC-0 currents opening the common gate and slowing its deactivation. No functional effect was seen for common gate deficient CLC-0 mutants. Similarly, GlialCAM targets the common gate deficient CLC-2 mutant E211V/H816A to cell contacts, without altering its function. Thus, GlialCAM is able to interact with all CLC channels tested, targeting them to cell junctions and activating them by stabilizing the open configuration of the common gate. These results are important to better understand the physiological role of GlialCAM/CLC-2 interaction.
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Affiliation(s)
- Elena Jeworutzki
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, 16149 Genoa, Italy; Departments of Anesthesia and Biomedizin, ZLF Lab 408, Universitätsspital Basel, Switzerland
| | - Laura Lagostena
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, 16149 Genoa, Italy
| | - Xabier Elorza-Vidal
- Physiology Section, Department of Physiological Sciences II, School of Medicine, Barcelona, Spain; U-750, Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Barcelona, Spain
| | - Tania López-Hernández
- Physiology Section, Department of Physiological Sciences II, School of Medicine, Barcelona, Spain; U-750, Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Barcelona, Spain; Department of Molecular Pharmacology and Cell Biology, FMP, Berlin, Germany
| | - Raúl Estévez
- Physiology Section, Department of Physiological Sciences II, School of Medicine, Barcelona, Spain; U-750, Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Barcelona, Spain
| | - Michael Pusch
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, 16149 Genoa, Italy.
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Leukoencephalopathy associated with 11q24 deletion involving the gene encoding hepatic and glial cell adhesion molecule in two patients. Eur J Med Genet 2015; 58:492-6. [DOI: 10.1016/j.ejmg.2015.06.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Accepted: 06/15/2015] [Indexed: 12/22/2022]
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Jentsch TJ. Discovery of CLC transport proteins: cloning, structure, function and pathophysiology. J Physiol 2015; 593:4091-109. [PMID: 25590607 DOI: 10.1113/jp270043] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 01/11/2015] [Indexed: 02/06/2023] Open
Abstract
After providing a personal description of the convoluted path leading 25 years ago to the molecular identification of the Torpedo Cl(-) channel ClC-0 and the discovery of the CLC gene family, I succinctly describe the general structural and functional features of these ion transporters before giving a short overview of mammalian CLCs. These can be categorized into plasma membrane Cl(-) channels and vesicular Cl(-) /H(+) -exchangers. They are involved in the regulation of membrane excitability, transepithelial transport, extracellular ion homeostasis, endocytosis and lysosomal function. Diseases caused by CLC dysfunction include myotonia, neurodegeneration, deafness, blindness, leukodystrophy, male infertility, renal salt loss, kidney stones and osteopetrosis, revealing a surprisingly broad spectrum of biological roles for chloride transport that was unsuspected when I set out to clone the first voltage-gated chloride channel.
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Affiliation(s)
- Thomas J Jentsch
- Leibniz-Institut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
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90
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Capdevila-Nortes X, Jeworutzki E, Elorza-Vidal X, Barrallo-Gimeno A, Pusch M, Estévez R. Structural determinants of interaction, trafficking and function in the ClC-2/MLC1 subunit GlialCAM involved in leukodystrophy. J Physiol 2015; 593:4165-80. [PMID: 26033718 DOI: 10.1113/jp270467] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 05/22/2015] [Indexed: 02/03/2023] Open
Abstract
KEY POINTS The extracellular domain of GlialCAM is necessary for its targeting to cell junctions, as well as for interactions with itself and MLC1 and ClC-2. The C-terminus of GlialCAM is not necessary for interaction but is required for targeting to cell junctions. The first three residues of the transmembrane segment of GlialCAM are required for GlialCAM-mediated ClC-2 activation. ABSTRACT Mutations in the genes encoding the astrocytic protein MLC1, the cell adhesion molecule GlialCAM or the Cl(-) channel ClC-2 underlie human leukodystrophies. GlialCAM binds to itself, to MLC1 and to ClC-2, and directs these proteins to cell-cell contacts. In addition, GlialCAM dramatically activates ClC-2 mediated currents. In the present study, we used mutagenesis studies combined with functional and biochemical analyses to determine which parts of GlialCAM are required to perform these cellular functions. We found that the extracellular domain of GlialCAM is necessary for cell junction targeting and for mediating interactions with itself or with MLC1 and ClC-2. The C-terminus is also necessary for proper targeting to cell-cell junctions but is not required for the biochemical interaction. Finally, we identified the first three amino acids of the transmembrane segment of GlialCAM as being essential for the activation of ClC-2 currents but not for targeting or biochemical interaction. Our results provide new mechanistic insights concerning the regulation of the cell biology and function of MLC1 and ClC-2 by GlialCAM.
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Affiliation(s)
- Xavier Capdevila-Nortes
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II, Universidad de Barcelona, Barcelona, Spain
| | - Elena Jeworutzki
- Istituto di Biofisica, CNR, Genoa, Italy.,Present address IfGH-Myocellular Electrophysiology, Department of Cardiovascular Medicine, University Hospital of Münster, Münster, Germany
| | - Xabier Elorza-Vidal
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II, Universidad de Barcelona, Barcelona, Spain.,U-750, Centro de investigación en red de enfermedades raras (CIBERER), ISCIII, Barcelona, Spain
| | - Alejandro Barrallo-Gimeno
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II, Universidad de Barcelona, Barcelona, Spain
| | | | - Raúl Estévez
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II, Universidad de Barcelona, Barcelona, Spain.,U-750, Centro de investigación en red de enfermedades raras (CIBERER), ISCIII, Barcelona, Spain
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91
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Abstract
Myelination of axons in the nervous system of vertebrates enables fast, saltatory impulse propagation, one of the best-understood concepts in neurophysiology. However, it took a long while to recognize the mechanistic complexity both of myelination by oligodendrocytes and Schwann cells and of their cellular interactions. In this review, we highlight recent advances in our understanding of myelin biogenesis, its lifelong plasticity, and the reciprocal interactions of myelinating glia with the axons they ensheath. In the central nervous system, myelination is also stimulated by axonal activity and astrocytes, whereas myelin clearance involves microglia/macrophages. Once myelinated, the long-term integrity of axons depends on glial supply of metabolites and neurotrophic factors. The relevance of this axoglial symbiosis is illustrated in normal brain aging and human myelin diseases, which can be studied in corresponding mouse models. Thus, myelinating cells serve a key role in preserving the connectivity and functions of a healthy nervous system.
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Affiliation(s)
- Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, D-37075 Göttingen, Germany; ,
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92
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Masuda T, Ueda M, Ueyama H, Shimada S, Ishizaki M, Imamura S, Yamamoto T, Ando Y. Megalencephalic leukoencephalopathy with subcortical cysts caused by compound heterozygous mutations in MLC1, in patients with and without subcortical cysts in the brain. J Neurol Sci 2015; 351:211-213. [PMID: 25796299 DOI: 10.1016/j.jns.2015.03.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 02/19/2015] [Accepted: 03/05/2015] [Indexed: 10/23/2022]
Affiliation(s)
- Teruaki Masuda
- Department of Neurology, National Hospital Organization, Kumamoto Saisyunsou Hospital, 2659 Suya, Koshi City, Kumamoto 861-1196, Japan; Department of Neurology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan
| | - Mitsuharu Ueda
- Department of Neurology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan.
| | - Hidetsugu Ueyama
- Department of Neurology, National Hospital Organization, Kumamoto Saisyunsou Hospital, 2659 Suya, Koshi City, Kumamoto 861-1196, Japan
| | - Shino Shimada
- Tokyo Women's Medical University Institute for Integrated Medical Sciences, 8-1 Kawata-cho, Shinjuku-ku, Tokyo, 162-8666, Japan
| | - Masatoshi Ishizaki
- Department of Neurology, National Hospital Organization, Kumamoto Saisyunsou Hospital, 2659 Suya, Koshi City, Kumamoto 861-1196, Japan
| | - Shigehiro Imamura
- Department of Neurology, National Hospital Organization, Kumamoto Saisyunsou Hospital, 2659 Suya, Koshi City, Kumamoto 861-1196, Japan
| | - Toshiyuki Yamamoto
- Tokyo Women's Medical University Institute for Integrated Medical Sciences, 8-1 Kawata-cho, Shinjuku-ku, Tokyo, 162-8666, Japan
| | - Yukio Ando
- Department of Neurology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan
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93
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Brignone MS, Lanciotti A, Camerini S, De Nuccio C, Petrucci TC, Visentin S, Ambrosini E. MLC1 protein: a likely link between leukodystrophies and brain channelopathies. Front Cell Neurosci 2015; 9:66. [PMID: 25883547 PMCID: PMC4381631 DOI: 10.3389/fncel.2015.00106] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 03/09/2015] [Indexed: 01/12/2023] Open
Abstract
Megalencephalic leukoencephalopathy with subcortical cysts (MLCs) disease is a rare inherited, autosomal recessive form of childhood-onset spongiform leukodystrophy characterized by macrocephaly, deterioration of motor functions, epileptic seizures and mental decline. Brain edema, subcortical fluid cysts, myelin and astrocyte vacuolation are the histopathological hallmarks of MLC. Mutations in either the MLC1 gene (>75% of patients) or the GlialCAM gene (<20% of patients) are responsible for the disease. Recently, the GlialCAM adhesion protein was found essential for the membrane expression and function of the chloride channel ClC-2 indicating MLC disease caused by mutation in GlialCAM as the first channelopathy among leukodystrophies. On the contrary, the function of MLC1 protein, which binds GlialCAM, its functional relationship with ClC-2 and the molecular mechanisms underlying MLC1 mutation-induced functional defects are not fully understood yet. The human MLC1 gene encodes a 377-amino acid membrane protein with eight predicted transmembrane domains which shows very low homology with voltage-dependent potassium (K+) channel subunits. The high expression of MLC1 in brain astrocytes contacting blood vessels and meninges and brain alterations observed in MLC patients have led to hypothesize a role for MLC1 in the regulation of ion and water homeostasis. Recent studies have shown that MLC1 establishes structural and/or functional interactions with several ion/water channels and transporters and ion channel accessory proteins, and that these interactions are affected by MLC1 mutations causing MLC. Here, we review data on MLC1 functional properties obtained in in vitro and in vivo models and discuss evidence linking the effects of MLC1 mutations to brain channelopathies.
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Affiliation(s)
- Maria S Brignone
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
| | - Angela Lanciotti
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
| | - Serena Camerini
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
| | - Chiara De Nuccio
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
| | - Tamara C Petrucci
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
| | - Sergio Visentin
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
| | - Elena Ambrosini
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
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94
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Shariati G, Hamid M, Saberi A, Andashti B, Galehdari H. Molecular prenatal diagnosis of megalencephalic leukoencephalopathy with subcortical cysts in a child from southwest of Iran. Clin Case Rep 2015; 3:114-7. [PMID: 25767710 PMCID: PMC4352366 DOI: 10.1002/ccr3.168] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 12/26/2013] [Accepted: 09/23/2014] [Indexed: 11/21/2022] Open
Abstract
Megalencephalic leukoencephalopathy (MLC) is a rare neurological disorder with an autosomal recessive pattern. Clinical diagnosis was based on macrocephaly, recurrent seizure, and magnetic resonance imaging (MRI). Here we report first finding of a novel homozygous single base deletion in the MLC1 gene in an affected Iranian child causing a premature stop codon (p.L150fs.160X).
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Affiliation(s)
| | - Mohammad Hamid
- Department of Biotechnology Pasteur Institute Tehran Iran
| | - Alihossein Saberi
- Department of Genetics Medical School of Ahvaz Jundishapur University Ahvaz Iran
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95
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Dubey M, Bugiani M, Ridder MC, Postma NL, Brouwers E, Polder E, Jacobs JG, Baayen JC, Klooster J, Kamermans M, Aardse R, de Kock CPJ, Dekker MP, van Weering JRT, Heine VM, Abbink TEM, Scheper GC, Boor I, Lodder JC, Mansvelder HD, van der Knaap MS. Mice with megalencephalic leukoencephalopathy with cysts: A developmental angle. Ann Neurol 2014; 77:114-31. [DOI: 10.1002/ana.24307] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 10/27/2014] [Accepted: 11/02/2014] [Indexed: 11/11/2022]
Affiliation(s)
- Mohit Dubey
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
- Department of Integrative Neurophysiology; Center for Neurogenomics and Cognitive Research, VU University
| | - Marianna Bugiani
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
- Department of Pathology; VU University Medical Center
| | - Margreet C. Ridder
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
| | - Nienke L. Postma
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
| | - Eelke Brouwers
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
- Department of Integrative Neurophysiology; Center for Neurogenomics and Cognitive Research, VU University
| | - Emiel Polder
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
| | - J. Gerbren Jacobs
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
- Department of Functional Genomics; Center for Neurogenomics and Cognitive Research, VU University
| | | | - Jan Klooster
- Department of Retinal Signal Processing; Netherlands Institute for Neuroscience-KNAW; Amsterdam Netherlands
| | - Maarten Kamermans
- Department of Retinal Signal Processing; Netherlands Institute for Neuroscience-KNAW; Amsterdam Netherlands
| | - Romy Aardse
- Department of Integrative Neurophysiology; Center for Neurogenomics and Cognitive Research, VU University
| | - Christiaan P. J. de Kock
- Department of Integrative Neurophysiology; Center for Neurogenomics and Cognitive Research, VU University
| | - Marien P. Dekker
- Department of Functional Genomics; Center for Neurogenomics and Cognitive Research, VU University
| | - Jan R. T. van Weering
- Department of Functional Genomics; Center for Neurogenomics and Cognitive Research, VU University
| | - Vivi M. Heine
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
- Department of Functional Genomics; Center for Neurogenomics and Cognitive Research, VU University
| | - Truus E. M. Abbink
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
| | - Gert C. Scheper
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
| | - Ilja Boor
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
| | - Johannes C. Lodder
- Department of Integrative Neurophysiology; Center for Neurogenomics and Cognitive Research, VU University
| | - Huibert D. Mansvelder
- Department of Integrative Neurophysiology; Center for Neurogenomics and Cognitive Research, VU University
| | - Marjo S. van der Knaap
- Department of Pediatrics/Child Neurology; Neuroscience Campus Amsterdam, VU University Medical Center
- Department of Functional Genomics; Center for Neurogenomics and Cognitive Research, VU University
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96
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Identification and characterization of the zebrafish ClC-2 chloride channel orthologs. Pflugers Arch 2014; 467:1769-81. [DOI: 10.1007/s00424-014-1614-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 09/09/2014] [Accepted: 09/09/2014] [Indexed: 12/31/2022]
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97
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Arnedo T, López-Hernández T, Jeworutzki E, Capdevila-Nortes X, Sirisi S, Pusch M, Estévez R. Functional Analyses of Mutations inHEPACAMCausing Megalencephalic Leukoencephalopathy. Hum Mutat 2014; 35:1175-8. [DOI: 10.1002/humu.22622] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 07/03/2014] [Indexed: 01/10/2023]
Affiliation(s)
- Tanit Arnedo
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II; University of Barcelona; Barcelona Spain
- U-750; Centro de Investigación en red de enfermedades raras (CIBERER), ISCIII; Barcelona Spain
| | - Tania López-Hernández
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II; University of Barcelona; Barcelona Spain
| | - Elena Jeworutzki
- Istituto di Biofisica; Consiglio Nazionale delle Ricerche; Genoa 16149 Italy
| | - Xavier Capdevila-Nortes
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II; University of Barcelona; Barcelona Spain
| | - Sònia Sirisi
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II; University of Barcelona; Barcelona Spain
| | - Michael Pusch
- Istituto di Biofisica; Consiglio Nazionale delle Ricerche; Genoa 16149 Italy
| | - Raúl Estévez
- Sección de Fisiología, Departamento de Ciencias Fisiológicas II; University of Barcelona; Barcelona Spain
- U-750; Centro de Investigación en red de enfermedades raras (CIBERER), ISCIII; Barcelona Spain
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98
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Brignone MS, Lanciotti A, Visentin S, De Nuccio C, Molinari P, Camerini S, Diociaiuti M, Petrini S, Minnone G, Crescenzi M, Laudiero LB, Bertini E, Petrucci TC, Ambrosini E. Megalencephalic leukoencephalopathy with subcortical cysts protein-1 modulates endosomal pH and protein trafficking in astrocytes: relevance to MLC disease pathogenesis. Neurobiol Dis 2014; 66:1-18. [PMID: 24561067 PMCID: PMC4003525 DOI: 10.1016/j.nbd.2014.02.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 01/20/2014] [Accepted: 02/10/2014] [Indexed: 11/28/2022] Open
Abstract
Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare leukodystrophy caused by mutations in the gene encoding MLC1, a membrane protein mainly expressed in astrocytes in the central nervous system. Although MLC1 function is unknown, evidence is emerging that it may regulate ion fluxes. Using biochemical and proteomic approaches to identify MLC1 interactors and elucidate MLC1 function we found that MLC1 interacts with the vacuolar ATPase (V-ATPase), the proton pump that regulates endosomal acidity. Because we previously showed that in intracellular organelles MLC1 directly binds Na, K-ATPase, which controls endosomal pH, we studied MLC1 endosomal localization and trafficking and MLC1 effects on endosomal acidity and function using human astrocytoma cells overexpressing wild-type (WT) MLC1 or MLC1 carrying pathological mutations. We found that WT MLC1 is abundantly expressed in early (EEA1(+), Rab5(+)) and recycling (Rab11(+)) endosomes and uses the latter compartment to traffic to the plasma membrane during hyposmotic stress. We also showed that WT MLC1 limits early endosomal acidification and influences protein trafficking in astrocytoma cells by stimulating protein recycling, as revealed by FITC-dextran measurement of endosomal pH and transferrin protein recycling assay, respectively. WT MLC1 also favors recycling to the plasma-membrane of the TRPV4 cation channel which cooperates with MLC1 to activate calcium influx in astrocytes during hyposmotic stress. Although MLC disease-causing mutations differentially affect MLC1 localization and trafficking, all the mutated proteins fail to influence endosomal pH and protein recycling. This study demonstrates that MLC1 modulates endosomal pH and protein trafficking suggesting that alteration of these processes contributes to MLC pathogenesis.
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Affiliation(s)
- Maria S Brignone
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Angela Lanciotti
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Sergio Visentin
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Chiara De Nuccio
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Paola Molinari
- Department of Pharmacology, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Serena Camerini
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Marco Diociaiuti
- Department of Technology and Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Stefania Petrini
- Unit of Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Pediatric Research Hospital, Piazza S. Onofrio 4, 00165 Rome, Italy.
| | - Gaetana Minnone
- Unit of Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Pediatric Research Hospital, Piazza S. Onofrio 4, 00165 Rome, Italy.
| | - Marco Crescenzi
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Luisa Bracci Laudiero
- Unit of Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Pediatric Research Hospital, Piazza S. Onofrio 4, 00165 Rome, Italy; Institute of Translational Pharmacology, CNR, Via del Fosso Cavaliere 100, 00133 Rome, Italy.
| | - Enrico Bertini
- Unit of Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Pediatric Research Hospital, Piazza S. Onofrio 4, 00165 Rome, Italy.
| | - Tamara C Petrucci
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Elena Ambrosini
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
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99
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Sirisi S, Folgueira M, López-Hernández T, Minieri L, Pérez-Rius C, Gaitán-Peñas H, Zang J, Martínez A, Capdevila-Nortes X, De La Villa P, Roy U, Alia A, Neuhauss S, Ferroni S, Nunes V, Estévez R, Barrallo-Gimeno A. Megalencephalic leukoencephalopathy with subcortical cysts protein 1 regulates glial surface localization of GLIALCAM from fish to humans. Hum Mol Genet 2014; 23:5069-86. [DOI: 10.1093/hmg/ddu231] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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100
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Yang E, Prabhu SP. Imaging manifestations of the leukodystrophies, inherited disorders of white matter. Radiol Clin North Am 2014; 52:279-319. [PMID: 24582341 DOI: 10.1016/j.rcl.2013.11.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The leukodystrophies are a diverse set of inherited white matter disorders and are uncommonly encountered by radiologists in everyday practice. As a result, it is challenging to recognize these disorders and to provide a useful differential for the referring physician. In this article, leukodystrophies are reviewed from the perspective of 4 imaging patterns: global myelination delay, periventricular/deep white matter predominant, subcortical white matter predominant, and mixed white/gray matter involvement patterns. Special emphasis is placed on pattern recognition and unusual combinations of findings that may suggest a specific diagnosis.
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Affiliation(s)
- Edward Yang
- Department of Radiology, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA.
| | - Sanjay P Prabhu
- Department of Radiology, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA
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