1
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Capponi S, Stöffler N, Penney EB, Grütz K, Nizamuddin S, Vermunt MW, Castelijns B, Fernandez-Cerado C, Legarda GP, Velasco-Andrada MS, Muñoz EL, Ang MA, Diesta CCE, Creyghton MP, Klein C, Bragg DC, De Rijk P, Timmers HTM. Dissection of TAF1 neuronal splicing and implications for neurodegeneration in X-linked dystonia-parkinsonism. Brain Commun 2021; 3:fcab253. [PMID: 34746789 PMCID: PMC8567410 DOI: 10.1093/braincomms/fcab253] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 08/16/2021] [Accepted: 08/19/2021] [Indexed: 11/29/2022] Open
Abstract
X-linked dystonia-parkinsonism (XDP) is a monogenic neurodegenerative disorder of the basal ganglia, which presents as a combination of hyperkinetic movements and parkinsonian features. The underlying genetic mechanism involves the insertion of a SINE-VNTR-Alu retrotransposon within the TAF1 gene. Interestingly, alterations of TAF1 have been involved in multiple neurological diseases. In XDP, the SINE-VNTR-Alu insertion in TAF1 has been proposed to result in alternative splicing defects, including the decreased incorporation of a neuron-specific microexon annotated as 34′. This mechanism has become controversial as recent studies failed to provide support. In order to resolve this conundrum, we examined the alternative splicing patterns of TAF1 mRNAs in XDP and control brains. The impact of the disease-associated SINE-VNTR-Alu on alternative splicing of microexon 34′ was further investigated in cellular assays. Subsequently, microexon 34′ incorporation was explored by RT-PCR and Nanopore long-read sequencing of TAF1 mRNAs from XDP and control brains tissues. Using cell-based splicing assays, we demonstrate that presence of the disease-associated SINE-VNTR-Alu does not affect the inclusion of microexon 34′. In addition, we show that (1) microexon 34′-containing TAF1 mRNAs are detected at similar levels in XDP as in controls and that (2) the architecture of TAF1 transcripts is remarkably similar between XDP and controls brains. These results indicate that microexon 34′ incorporation into TAF1 mRNA is not affected in XDP brains. Our findings shift the current paradigm of XDP by discounting alternative splicing of TAF1 microexon 34′ as the molecular basis for this disease.
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Affiliation(s)
- Simona Capponi
- German Cancer Consortium (DKTK), Partner Site Freiburg, German Cancer Research Center (DKFZ), Department of Urology, Medical Center-University of Freiburg, 79106 Freiburg, Germany
| | - Nadja Stöffler
- German Cancer Consortium (DKTK), Partner Site Freiburg, German Cancer Research Center (DKFZ), Department of Urology, Medical Center-University of Freiburg, 79106 Freiburg, Germany
| | - Ellen B Penney
- The Collaborative Center for X-Linked Dystonia Parkinsonism (CCXDP), Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129, USA
| | - Karen Grütz
- Institute of Neurogenetics, University of Lübeck, Lübeck 23538, Germany
| | - Sheikh Nizamuddin
- German Cancer Consortium (DKTK), Partner Site Freiburg, German Cancer Research Center (DKFZ), Department of Urology, Medical Center-University of Freiburg, 79106 Freiburg, Germany
| | - Marit W Vermunt
- Erasmus University Medical Center, Department of Developmental Biology, Rotterdam 3015 GD, The Netherlands
| | - Bas Castelijns
- Erasmus University Medical Center, Department of Developmental Biology, Rotterdam 3015 GD, The Netherlands
| | | | - G Paul Legarda
- Sunshine Care Foundation, Roxas City, 5800 Capiz, Philippines
| | | | - Edwin L Muñoz
- Department of Pathology, College of Medicine, University of the Philippines, 1000 Manila, Philippines
| | - Mark A Ang
- Department of Pathology, College of Medicine, University of the Philippines, 1000 Manila, Philippines
| | - Cid Czarina E Diesta
- Department of Neurosciences, Makati Medical Center, 1229 Makati City, Philippines
| | - Menno P Creyghton
- Erasmus University Medical Center, Department of Developmental Biology, Rotterdam 3015 GD, The Netherlands
| | - Christine Klein
- Institute of Neurogenetics and Department of Neurology, University of Lübeck, 23538 Lübeck, Germany
| | - D Cristopher Bragg
- The Collaborative Center for X-Linked Dystonia Parkinsonism (CCXDP), Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129, USA
| | - Peter De Rijk
- Neuromics Support Facility, VIB Center for Molecular Neurology, VIB - University of Antwerp, B-2610 Antwerp, Belgium
| | - H T Marc Timmers
- German Cancer Consortium (DKTK), Partner Site Freiburg, German Cancer Research Center (DKFZ), Department of Urology, Medical Center-University of Freiburg, 79106 Freiburg, Germany
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2
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Cheng H, Capponi S, Wakeling E, Marchi E, Li Q, Zhao M, Weng C, Piatek SG, Ahlfors H, Kleyner R, Rope A, Lumaka A, Lukusa P, Devriendt K, Vermeesch J, Posey JE, Palmer EE, Murray L, Leon E, Diaz J, Worgan L, Mallawaarachchi A, Vogt J, de Munnik SA, Dreyer L, Baynam G, Ewans L, Stark Z, Lunke S, Gonçalves AR, Soares G, Oliveira J, Fassi E, Willing M, Waugh JL, Faivre L, Riviere JB, Moutton S, Mohammed S, Payne K, Walsh L, Begtrup A, Sacoto MJG, Douglas G, Alexander N, Buckley MF, Mark PR, Adès LC, Sandaradura SA, Lupski JR, Roscioli T, Agrawal PB, Kline AD, Wang K, Timmers HTM, Lyon GJ. Missense variants in TAF1 and developmental phenotypes: challenges of determining pathogenicity. Hum Mutat 2019; 41:10.1002/humu.23936. [PMID: 31646703 PMCID: PMC7187541 DOI: 10.1002/humu.23936] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 10/16/2019] [Indexed: 12/26/2022]
Abstract
We recently described a new neurodevelopmental syndrome (TAF1/MRXS33 intellectual disability syndrome) (MIM# 300966) caused by pathogenic variants involving the X-linked gene TAF1, which participates in RNA polymerase II transcription. The initial study reported eleven families, and the syndrome was defined as presenting early in life with hypotonia, facial dysmorphia, and developmental delay that evolved into intellectual disability (ID) and/or autism spectrum disorder (ASD). We have now identified an additional 27 families through a genotype-first approach. Familial segregation analysis, clinical phenotyping, and bioinformatics were capitalized on to assess potential variant pathogenicity, and molecular modelling was performed for those variants falling within structurally characterized domains of TAF1. A novel phenotypic clustering approach was also applied, in which the phenotypes of affected individuals were classified using 51 standardized Human Phenotype Ontology (HPO) terms. Phenotypes associated with TAF1 variants show considerable pleiotropy and clinical variability, but prominent among previously unreported effects were brain morphological abnormalities, seizures, hearing loss, and heart malformations. Our allelic series broadens the phenotypic spectrum of TAF1/MRXS33 intellectual disability syndrome and the range of TAF1 molecular defects in humans. It also illustrates the challenges for determining the pathogenicity of inherited missense variants, particularly for genes mapping to chromosome X. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Hanyin Cheng
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Simona Capponi
- German Cancer Consortium (DKTK), Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Department of Urology, Medical Faculty-University of Freiburg, Freiburg, Germany
| | - Emma Wakeling
- North West Thames Regional Genetics Service, London North West University Healthcare NHS Trust, Harrow, UK
| | - Elaine Marchi
- Institute for Basic Research in Developmental Disabilities (IBR), Staten Island, New York
| | - Quan Li
- Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Mengge Zhao
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Chunhua Weng
- Department of Biomedical Informatics, Columbia University Medical Center, New York, New York
| | - Stefan G. Piatek
- North East Thames Regional Genetics Laboratory, Great Ormond Street Hospital, London, UK
| | - Helena Ahlfors
- North East Thames Regional Genetics Laboratory, Great Ormond Street Hospital, London, UK
| | - Robert Kleyner
- Stanley Institute for Cognitive Genomics, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York
| | - Alan Rope
- Kaiser Permanente Center for Health Research, Portland, Oregon
- Genome Medical, South San Francisco, California
| | - Aimé Lumaka
- Department of Biomedical and Preclinical Sciences, GIGA-R, Laboratory of Human Genetics, University of Liège, Liège, Belgium
- Institut National de Recherche Biomédicale, Kinshasa, DR Congo
- Centre for Human Genetics, Faculty of Medicine, University of Kinshasa, Kinshasa, DR Congo
| | - Prosper Lukusa
- Institut National de Recherche Biomédicale, Kinshasa, DR Congo
- Centre for Human Genetics, Faculty of Medicine, University of Kinshasa, Kinshasa, DR Congo
- Centre for Human Genetics, University Hospital, University of Leuven, Leuven, Belgium
| | - Koenraad Devriendt
- Centre for Human Genetics, University Hospital, University of Leuven, Leuven, Belgium
| | - Joris Vermeesch
- Centre for Human Genetics, University Hospital, University of Leuven, Leuven, Belgium
| | - Jennifer E. Posey
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Elizabeth E. Palmer
- Genetics of Learning Disability Service, Newcastle, New South Wales, Australia
- School of Women’s and Children’s Health, University of New South Wales, Randwick, New South Wales, Australia
| | - Lucinda Murray
- Genetics of Learning Disability Service, Newcastle, New South Wales, Australia
| | - Eyby Leon
- Rare Disease Institute, Children’s National Health System, Washington, District of Columbia
| | - Jullianne Diaz
- Rare Disease Institute, Children’s National Health System, Washington, District of Columbia
| | - Lisa Worgan
- Department of Clinical Genetics, Liverpool Hospital, Sydney, New South Wales, Australia
| | - Amali Mallawaarachchi
- Department of Clinical Genetics, Liverpool Hospital, Sydney, New South Wales, Australia
| | - Julie Vogt
- West Midlands Regional Clinical Genetics Service and Birmingham Health Partners, Birmingham Women’s and Children’s Hospitals NHS Foundation Trust, Birmingham, UK
| | - Sonja A. de Munnik
- Department of Human Genetics, Institute for Genetic and Metabolic Disease, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Lauren Dreyer
- Genetic Services of Western Australia, Undiagnosed Diseases Program, Perth, Western Australia, Australia
| | - Gareth Baynam
- Genetic Services of Western Australia, Undiagnosed Diseases Program, Perth, Western Australia, Australia
- Western Australian Register of Developmental Anomalies, Perth, Western Australia, Australia
- Institute for Immunology and Infectious Diseases, Murdoch University, Perth, Western Australia, Australia
- Telethon Kids Institute, Perth, Western Australia, Australia
- Division of Paediatrics, School of Medicine, University of Western Australia, Perth, Western Australia, Australia
| | - Lisa Ewans
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | - Zornitza Stark
- Victorian Clinical Genetics Services, Murdoch Children’s Research Institute, Melbourne, Victoria, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
- Australian Genomics Health Alliance, Melbourne, Victoria, Australia
| | - Sebastian Lunke
- Victorian Clinical Genetics Services, Murdoch Children’s Research Institute, Melbourne, Victoria, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
- Australian Genomics Health Alliance, Melbourne, Victoria, Australia
| | - Ana R. Gonçalves
- Center for Medical Genetics Dr. Jacinto de Magalhāes, Hospital and University Center of Porto, Porto, Portugal
| | - Gabriela Soares
- Center for Medical Genetics Dr. Jacinto de Magalhāes, Hospital and University Center of Porto, Porto, Portugal
| | - Jorge Oliveira
- Center for Medical Genetics Dr. Jacinto de Magalhāes, Hospital and University Center of Porto, Porto, Portugal
- unIGENe, and Center for Predictive and Preventive Genetics (CGPP), Institute for Molecular and Cell Biology (IBMC), Institute of Health Research and Innovation (i3S), University of Porto, Porto, Portugal
| | - Emily Fassi
- Department of Pediatrics, Division of Genetics and Genomic Medicine, Washington University School of Medicine, St. Louis, Michigan
| | - Marcia Willing
- Department of Pediatrics, Division of Genetics and Genomic Medicine, Washington University School of Medicine, St. Louis, Michigan
| | - Jeff L. Waugh
- Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
- Department of Pediatrics, Division of Pediatric Neurology, University of Texas Southwestern, Dallas, Texas
| | - Laurence Faivre
- INSERM U1231, LNC UMR1231 GAD, Burgundy University, Dijon, France
| | | | - Sebastien Moutton
- INSERM U1231, LNC UMR1231 GAD, Burgundy University, Dijon, France
- Department of Medical Genetics, Reference Center for Developmental Anomalies, Bordeaux University Hospital, Bordeaux, France
| | | | - Katelyn Payne
- Department of Neurology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Laurence Walsh
- Department of Neurology, Indiana University School of Medicine, Indianapolis, Indiana
| | | | | | | | | | - Michael F. Buckley
- New South Wales Health Pathology Genomic Laboratory, Prince of Wales Hospital, Randwick, New South Wales, Australia
| | - Paul R. Mark
- Spectrum Health Division of Medical and Molecular Genetics, Grand Rapids, Michigan
| | - Lesley C. Adès
- Department of Paediatrics and Child Health, University of Sydney, Sydney, New South Wales, Australia
- Department of Genetics, The Children’s Hospital at Westmead, Sydney, New South Wales, Australia
| | - Sarah A. Sandaradura
- Department of Paediatrics and Child Health, University of Sydney, Sydney, New South Wales, Australia
- Department of Genetics, The Children’s Hospital at Westmead, Sydney, New South Wales, Australia
| | - James R. Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas
- Department of Pediatrics, Texas Children’s Hospital, Houston, Texas
| | - Tony Roscioli
- New South Wales Health Pathology Genomic Laboratory, Prince of Wales Hospital, Randwick, New South Wales, Australia
- Centre for Clinical Genetics, Sydney Children’s Hospital, Randwick, New South Wales, Australia
- Neuroscience Research Australia, University of New South Wales, Sydney, New South Wales, Australia
| | - Pankaj B. Agrawal
- Divisions of Newborn Medicine and Genetics and Genomics, Manton Center for Orphan Disease Research, Boston Children’s Hospital, Harvard Medical School, Boston, Maryland
| | - Antonie D. Kline
- Harvey Institute for Human Genetics, Greater Baltimore Medical Center, Baltimore, Maryland
| | | | - Kai Wang
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania
| | - H. T. Marc Timmers
- German Cancer Consortium (DKTK), Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Department of Urology, Medical Faculty-University of Freiburg, Freiburg, Germany
| | - Gholson J. Lyon
- Institute for Basic Research in Developmental Disabilities (IBR), Staten Island, New York
- Stanley Institute for Cognitive Genomics, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York
- The Graduate Center, The City University of New York, New York, New York
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3
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Capponi S, Stöffler N, Irimia M, Van Schaik FMA, Ondik MM, Biniossek ML, Lehmann L, Mitschke J, Vermunt MW, Creyghton MP, Graybiel AM, Reinheckel T, Schilling O, Blencowe BJ, Crittenden JR, Timmers HTM. Neuronal-specific microexon splicing of TAF1 mRNA is directly regulated by SRRM4/nSR100. RNA Biol 2019; 17:62-74. [PMID: 31559909 PMCID: PMC6948980 DOI: 10.1080/15476286.2019.1667214] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Neuronal microexons represent the most highly conserved class of alternative splicing events and their timed expression shapes neuronal biology, including neuronal commitment and differentiation. The six-nt microexon 34ʹ is included in the neuronal form of TAF1 mRNA, which encodes the largest subunit of the basal transcription factor TFIID. In this study, we investigate the tissue distribution of TAF1-34ʹ mRNA and protein and the mechanism responsible for its neuronal-specific splicing. Using isoform-specific RNA probes and antibodies, we observe that canonical TAF1 and TAF1-34ʹ have different distributions in the brain, which distinguish proliferating from post-mitotic neurons. Knockdown and ectopic expression experiments demonstrate that the neuronal-specific splicing factor SRRM4/nSR100 promotes the inclusion of microexon 34ʹ into TAF1 mRNA, through the recognition of UGC sequences in the poly-pyrimidine tract upstream of the regulated microexon. These results show that SRRM4 regulates temporal and spatial expression of alternative TAF1 mRNAs to generate a neuronal-specific TFIID complex.
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Affiliation(s)
- Simona Capponi
- German Cancer Consortium (DKTK) partner site Freiburg, German Cancer Research Center (DKFZ) and Department of Urology, Medical Center-University of Freiburg, Freiburg, Germany
| | - Nadja Stöffler
- German Cancer Consortium (DKTK) partner site Freiburg, German Cancer Research Center (DKFZ) and Department of Urology, Medical Center-University of Freiburg, Freiburg, Germany
| | - Manuel Irimia
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation, The Barcelona Institute for Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Frederik M A Van Schaik
- Molecular Cancer Research and Stem Cells, Regenerative Medicine Center and Center for Molecular Medicine, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Mercedes M Ondik
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Martin L Biniossek
- Institute of Molecular Medicine and Cell Research, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Lisa Lehmann
- Institute of Molecular Medicine and Cell Research, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Julia Mitschke
- Institute of Molecular Medicine and Cell Research, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Marit W Vermunt
- Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, The Netherlands
| | - Menno P Creyghton
- Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, The Netherlands
| | - Ann M Graybiel
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Thomas Reinheckel
- Institute of Molecular Medicine and Cell Research, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,German Cancer Research Center (DKFZ), Heidelberg, and German Cancer Consortium (DKTK) partner site Freiburg, Germany
| | - Oliver Schilling
- Institute of Surgical Pathology, Faculty of Medicine-University of Freiburg, Freiburg, Germany
| | - Benjamin J Blencowe
- Donnelly Centre and Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Jill R Crittenden
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - H Th Marc Timmers
- German Cancer Consortium (DKTK) partner site Freiburg, German Cancer Research Center (DKFZ) and Department of Urology, Medical Center-University of Freiburg, Freiburg, Germany
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4
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Orlova A, Mayaffre H, Krämer S, Dupont M, Capponi S, Laflorencie N, Paduan-Filho A, Horvatić M. Detection of a Disorder-Induced Bose-Einstein Condensate in a Quantum Spin Material at High Magnetic Fields. Phys Rev Lett 2018; 121:177202. [PMID: 30411922 DOI: 10.1103/physrevlett.121.177202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Indexed: 06/08/2023]
Abstract
The coupled spin-1 chains material NiCl_{2}-4SC(NH_{2})_{2} (DTN) doped with Br impurities is expected to be a perfect candidate for observing many-body localization at high magnetic field: the so-called "Bose glass," a zero-temperature bosonic fluid, compressible, gapless, incoherent, and short-range correlated. Using nuclear magnetic resonance, we critically address the stability of the Bose glass in doped DTN, and find that it hosts a novel disorder-induced ordered state of matter, where many-body physics leads to an unexpected resurgence of quantum coherence emerging from localized impurity states. An experimental phase diagram of this new "order-from-disorder" phase, established from nuclear magnetic resonance T_{1}^{-1} relaxation rate data in the 13±1% Br-doped DTN, is found to be in excellent agreement with the theoretical prediction from large-scale quantum Monte Carlo simulations.
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Affiliation(s)
- A Orlova
- Laboratoire National des Champs Magnétiques Intenses, LNCMI-CNRS (UPR3228), EMFL, UGA, UPS, and INSA, Boîte Postale 166, 38042, Grenoble Cedex 9, France
| | - H Mayaffre
- Laboratoire National des Champs Magnétiques Intenses, LNCMI-CNRS (UPR3228), EMFL, UGA, UPS, and INSA, Boîte Postale 166, 38042, Grenoble Cedex 9, France
| | - S Krämer
- Laboratoire National des Champs Magnétiques Intenses, LNCMI-CNRS (UPR3228), EMFL, UGA, UPS, and INSA, Boîte Postale 166, 38042, Grenoble Cedex 9, France
| | - M Dupont
- Laboratoire de Physique Théorique, IRSAMC, Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - S Capponi
- Laboratoire de Physique Théorique, IRSAMC, Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - N Laflorencie
- Laboratoire de Physique Théorique, IRSAMC, Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - A Paduan-Filho
- Instituto de Física, Universidade de São Paulo, 05315-970 São Paulo, Brazil
| | - M Horvatić
- Laboratoire National des Champs Magnétiques Intenses, LNCMI-CNRS (UPR3228), EMFL, UGA, UPS, and INSA, Boîte Postale 166, 38042, Grenoble Cedex 9, France
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Parmeggiani A, Boiani F, Capponi S, Duca M, Angotti M, Pignataro V, Sacrato L, Spinardi L, Vara G, Maltoni L, Cecconi I, Pastore Trossello M, Franzoni E. Neuropsychological profile in Italian children with neurofibromatosis type 1 (NF1) and their relationships with neuroradiological data: Preliminary results. Eur J Paediatr Neurol 2018; 22:822-830. [PMID: 29802023 DOI: 10.1016/j.ejpn.2018.04.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 04/04/2018] [Accepted: 04/29/2018] [Indexed: 11/28/2022]
Abstract
BACKGROUND Neurofibromatosis type 1 is a genetic disorder associated with cognitive deficits, learning disabilities and behavioral problems. These domains appear to have a still controversial debated association with local areas of T2-hyperintensities on MRI images, called unidentified bright objects (UBOs). METHODS A cohort of 36 children (aged 7-11 years) included consecutively, underwent neuropsychological and behavioral assessment to determine their cognitive and neuropsychological profile, and the frequency of specific learning disabilities. MRI examination was used to determine the impact of UBOs' presence, number, and location on the cognitive, neuropsychological and behavioral profile, and also the presence of optic glioma. RESULTS The mean full intelligence quotient was 104.6; only one child had mild intellectual disability. Forty one percent of children had a diagnosis of specific learning disabilities and reading was mainly involved. Twenty per cent had attention problems. All children had normal scores in visuo-motor and visuo-perceptual tests. UBOs were present in 94.0% of the MRI examinations. Two children had optic glioma. Children with UBOs in a specific location and children with UBOs elsewhere were statistically compared, no one of the location seemed to have an impact on general cognition measured with full intelligence quotient. The thalamus was associated with problems in calculation and striatum with behavioral problems. An inverse relationship between the number of UBOs and the full intelligence quotient was present, but without a statistical significance. CONCLUSIONS In this study, the specific location of UBOs did not seem to influence the general cognitive profile and also the relationship between their number and the full intelligence quotient was not significant; these results are still controversial in literature. Finally, the presence of UBOs in the thalamus and striatum may represent a neuroradiological pattern that influences performances in calculation and behavior respectively in children with Neurofibromatosis type 1.
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Affiliation(s)
- A Parmeggiani
- Child Neurology and Psychiatry Unit, Azienda Ospedaliero Universitaria, Policlinico S. Orsola-Malpighi, Bologna, Italy; Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Italy.
| | - F Boiani
- Child Neurology and Psychiatry Unit, Azienda Ospedaliero Universitaria, Policlinico S. Orsola-Malpighi, Bologna, Italy
| | - S Capponi
- Child Neurology and Psychiatry Unit, Azienda Ospedaliero Universitaria, Policlinico S. Orsola-Malpighi, Bologna, Italy
| | - M Duca
- Child Neurology and Psychiatry Unit, Azienda Ospedaliero Universitaria, Policlinico S. Orsola-Malpighi, Bologna, Italy
| | - M Angotti
- Child Neurology and Psychiatry Unit, Azienda Ospedaliero Universitaria, Policlinico S. Orsola-Malpighi, Bologna, Italy
| | - V Pignataro
- Child Neurology and Psychiatry Unit, Azienda Ospedaliero Universitaria, Policlinico S. Orsola-Malpighi, Bologna, Italy
| | - L Sacrato
- Child Neurology and Psychiatry Unit, Azienda Ospedaliero Universitaria, Policlinico S. Orsola-Malpighi, Bologna, Italy
| | - L Spinardi
- Neuroradiology Unit, Azienda Ospedaliero Universitaria, Policlinico S. Orsola-Malpighi, Bologna, Italy
| | - G Vara
- Neuroradiology Unit, Azienda Ospedaliero Universitaria, Policlinico S. Orsola-Malpighi, Bologna, Italy
| | - L Maltoni
- Child Neurology and Psychiatry Unit, Azienda Ospedaliero Universitaria, Policlinico S. Orsola-Malpighi, Bologna, Italy
| | - I Cecconi
- Child Neurology and Psychiatry Unit, Azienda Ospedaliero Universitaria, Policlinico S. Orsola-Malpighi, Bologna, Italy
| | - M Pastore Trossello
- Neuroradiology Unit, Azienda Ospedaliero Universitaria, Policlinico S. Orsola-Malpighi, Bologna, Italy
| | - E Franzoni
- Child Neurology and Psychiatry Unit, Azienda Ospedaliero Universitaria, Policlinico S. Orsola-Malpighi, Bologna, Italy; Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Italy
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6
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Echaniz-Laguna A, Geuens T, Petiot P, Péréon Y, Adriaenssens E, Haidar M, Capponi S, Maisonobe T, Fournier E, Dubourg O, Degos B, Salachas F, Lenglet T, Eymard B, Delmont E, Pouget J, Juntas Morales R, Goizet C, Latour P, Timmerman V, Stojkovic T. Axonal Neuropathies due to Mutations in Small Heat Shock Proteins: Clinical, Genetic, and Functional Insights into Novel Mutations. Hum Mutat 2017; 38:556-568. [PMID: 28144995 DOI: 10.1002/humu.23189] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 01/29/2017] [Indexed: 12/12/2022]
Abstract
In this study, we describe the phenotypic spectrum of distal hereditary motor neuropathy caused by mutations in the small heat shock proteins HSPB1 and HSPB8 and investigate the functional consequences of newly discovered variants. Among 510 unrelated patients with distal motor neuropathy, we identified mutations in HSPB1 (28 index patients/510; 5.5%) and HSPB8 (four index patients/510; 0.8%) genes. Patients have slowly progressive distal (100%) and proximal (13%) weakness in lower limbs (100%), mild lower limbs sensory involvement (31%), foot deformities (73%), progressive distal upper limb weakness (29%), mildly raised serum creatine kinase levels (100%), and central nervous system involvement (9%). We identified 12 HSPB1 and four HSPB8 mutations, including five and three not previously reported. Transmission was either dominant (78%), recessive (3%), or de novo (19%). Three missense mutations in HSPB1 (Pro7Ser, Gly53Asp, and Gln128Arg) cause hyperphosphorylation of neurofilaments, whereas the C-terminal mutant Ser187Leu triggers protein aggregation. Two frameshift mutations (Leu58fs and Ala61fs) create a premature stop codon leading to proteasomal degradation. Two mutations in HSPB8 (Lys141Met/Asn) exhibited increased binding to Bag3. We demonstrate that HSPB1 and HSPB8 mutations are a major cause of inherited motor axonal neuropathy. Mutations lead to diverse functional outcomes further demonstrating the pleotropic character of small heat shock proteins.
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Affiliation(s)
- Andoni Echaniz-Laguna
- Department of Neurology, Neuromuscular Disease Centre (CERNEST), Strasbourg University Hospital, Strasbourg, France
| | - Thomas Geuens
- Peripheral Neuropathy Group, VIB Department of Molecular Genetics and Institute Born Bunge, University of Antwerp, Antwerpen, Belgium
| | - Philippe Petiot
- Neuromuscular Disease Centre, Lyon University Hospital, Lyon, France
| | - Yann Péréon
- Neuromuscular Disease Centre, Nantes University Hospital, Nantes, France
| | - Elias Adriaenssens
- Peripheral Neuropathy Group, VIB Department of Molecular Genetics and Institute Born Bunge, University of Antwerp, Antwerpen, Belgium
| | - Mansour Haidar
- Peripheral Neuropathy Group, VIB Department of Molecular Genetics and Institute Born Bunge, University of Antwerp, Antwerpen, Belgium
| | - Simona Capponi
- Peripheral Neuropathy Group, VIB Department of Molecular Genetics and Institute Born Bunge, University of Antwerp, Antwerpen, Belgium
| | - Thierry Maisonobe
- Neuromuscular Disease Centre, Hôpital de la Pitié-Salpétrière, APHP, Paris, France
| | - Emmanuel Fournier
- Neuromuscular Disease Centre, Hôpital de la Pitié-Salpétrière, APHP, Paris, France
| | - Odile Dubourg
- Neuromuscular Disease Centre, Hôpital de la Pitié-Salpétrière, APHP, Paris, France
| | - Bertrand Degos
- APHP, Department of Neurology, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - François Salachas
- APHP, Department of Neurology, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Timothée Lenglet
- Neuromuscular Disease Centre, Hôpital de la Pitié-Salpétrière, APHP, Paris, France
| | - Bruno Eymard
- Neuromuscular Disease Centre, Hôpital de la Pitié-Salpétrière, APHP, Paris, France
| | - Emilien Delmont
- Neuromuscular Disease Centre, Nice University Hospital, Nice, France
| | - Jean Pouget
- Neuromuscular Disease Centre, Marseille University Hospital, APHM, Marseille, France
| | - Raul Juntas Morales
- Neuromuscular Disease Centre, Montpellier University Hospital, Montpellier, France
| | - Cyril Goizet
- Department of Genetics, Bordeaux University Hospital, Bordeaux, France
| | - Philippe Latour
- Biology and Pathology Department, Lyon University Hospital, Bron, France
| | - Vincent Timmerman
- Peripheral Neuropathy Group, VIB Department of Molecular Genetics and Institute Born Bunge, University of Antwerp, Antwerpen, Belgium
| | - Tanya Stojkovic
- Neuromuscular Disease Centre, Hôpital de la Pitié-Salpétrière, APHP, Paris, France
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Tufano M, Cappuccio G, Terrone G, Manganelli F, Pisciotta C, Geroldi A, Capponi S, Del Giudice E. Early onset Charcot-Marie-Tooth neuropathy type 2A and severe developmental delay: expanding the clinical phenotype of MFN2-related neuropathy. J Peripher Nerv Syst 2016; 20:415-8. [PMID: 26307494 DOI: 10.1111/jns.12148] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Revised: 08/20/2015] [Accepted: 08/21/2015] [Indexed: 11/29/2022]
Abstract
Charcot-Marie-Tooth (CMT) syndromes are a group of clinically heterogeneous disorders of the peripheral nervous system. Mutations of mitofusin 2 (MFN2) have been recognized to be associated with CMT type 2A (CMT2A). CMT2A is primarily an axonal disorder resulting in motor and sensory neuropathy. We report a male child with psychomotor delay, dysmorphic features, and weakness of lower limbs associated with electrophysiological features of severe, sensory-motor, axonal neuropathy. The patient was diagnosed with early onset CMT2A and severe psychomotor retardation associated with c.310C>T mutation (p.R104W) in MFN2 gene. CMT2A should be considered in patients with both axonal sensory-motor neuropathy and developmental delay.
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Affiliation(s)
- Maria Tufano
- Metabolic and Neuromuscular Unit, Meyer Hospital, Florence, Italy
| | - Gerarda Cappuccio
- Department of Translational Medical Sciences, Section of Pediatrics, University Federico II of Naples, Naples, Italy
| | - Gaetano Terrone
- Department of Translational Medical Sciences, Section of Pediatrics, University Federico II of Naples, Naples, Italy
| | - Fiore Manganelli
- Department of Neurological Sciences, University Federico II of Naples, Naples, Italy
| | - Chiara Pisciotta
- Department of Neurological Sciences, University Federico II of Naples, Naples, Italy
| | - Alessandro Geroldi
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal Child Science, Section of Medical Genetics, University of Genoa, Genoa, Italy
| | - Simona Capponi
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal Child Science, Section of Medical Genetics, University of Genoa, Genoa, Italy
| | - Ennio Del Giudice
- Department of Translational Medical Sciences, Section of Pediatrics, University Federico II of Naples, Naples, Italy
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Capponi S, Geuens T, Geroldi A, Origone P, Verdiani S, Cichero E, Adriaenssens E, De Winter V, Bandettini di Poggio M, Barberis M, Chiò A, Fossa P, Mandich P, Bellone E, Timmerman V. Molecular Chaperones in the Pathogenesis of Amyotrophic Lateral Sclerosis: The Role of HSPB1. Hum Mutat 2016; 37:1202-1208. [PMID: 27492805 PMCID: PMC5108433 DOI: 10.1002/humu.23062] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 07/21/2016] [Accepted: 07/22/2016] [Indexed: 11/16/2022]
Abstract
Genetic discoveries in amyotrophic lateral sclerosis (ALS) have a significant impact on deciphering molecular mechanisms of motor neuron degeneration but, despite recent advances, the etiology of most sporadic cases remains elusive. Several cellular mechanisms contribute to the motor neuron degeneration in ALS, including RNA metabolism, cellular interactions between neurons and nonneuronal cells, and seeding of misfolded protein with prion‐like propagation. In this scenario, the importance of protein turnover and degradation in motor neuron homeostasis gained increased recognition. In this study, we evaluated the role of the candidate gene HSPB1, a molecular chaperone involved in several proteome‐maintenance functions. In a cohort of 247 unrelated Italian ALS patients, we identified two variants (c.570G>C, p.Gln190His and c.610dupG, p.Ala204Glyfs*6). Functional characterization of the p.Ala204Glyfs*6 demonstrated that the mutant protein alters HSPB1 dynamic equilibrium, sequestering the wild‐type protein in a stable dimer and resulting in a loss of chaperone‐like activity. Our results underline the relevance of identifying rare but pathogenic variations in sporadic neurodegenerative diseases, suggesting a possible correlation between specific pathomechanisms linked to HSPB1 mutations and the associated neurological phenotype. Our study provides additional lines of evidence to support the involvement of HSPB1 in the pathogenesis of sporadic ALS.
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Affiliation(s)
- Simona Capponi
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health, Section of Medical Genetics, University of Genoa, Genoa, Italy.,VIB Department of Molecular Genetics, Peripheral Neuropathy Group, Born Bunge Foundation, University of Antwerp, Antwerp, Belgium
| | - Thomas Geuens
- VIB Department of Molecular Genetics, Peripheral Neuropathy Group, Born Bunge Foundation, University of Antwerp, Antwerp, Belgium
| | - Alessandro Geroldi
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health, Section of Medical Genetics, University of Genoa, Genoa, Italy
| | - Paola Origone
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health, Section of Medical Genetics, University of Genoa, Genoa, Italy.,COU Medical Genetics, IRCCS AOU San Martino IST-Istituto Nazionale per la Ricerca sul Cancro, Genoa, Italy
| | | | - Elena Cichero
- Section of Medicinal Chemistry, Department of Pharmacy, School of Medical and Pharmaceutical Sciences, University of Genoa, Genoa, Italy
| | - Elias Adriaenssens
- VIB Department of Molecular Genetics, Peripheral Neuropathy Group, Born Bunge Foundation, University of Antwerp, Antwerp, Belgium
| | - Vicky De Winter
- VIB Department of Molecular Genetics, Peripheral Neuropathy Group, Born Bunge Foundation, University of Antwerp, Antwerp, Belgium
| | - Monica Bandettini di Poggio
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, IRCCS AOU San Martino-IST Istituto Nazionale per la Ricerca sul Cancro, University of Genova, Genoa, Italy
| | - Marco Barberis
- Rita Levi Montalcini Department of Neuroscience, University of Turin, Turin, Italy.,Laboratory of Molecular Genetics, Azienda Ospedaliero Universitaria Città della Salute e della Scienza di Torino, Turin, Italy
| | - Adriano Chiò
- Rita Levi Montalcini Department of Neuroscience, University of Turin, Turin, Italy.,Azienda Ospedaliero Universitaria Città della Salute e della Scienza, Turin, Italy
| | - Paola Fossa
- Section of Medicinal Chemistry, Department of Pharmacy, School of Medical and Pharmaceutical Sciences, University of Genoa, Genoa, Italy
| | - Paola Mandich
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health, Section of Medical Genetics, University of Genoa, Genoa, Italy.,COU Medical Genetics, IRCCS AOU San Martino IST-Istituto Nazionale per la Ricerca sul Cancro, Genoa, Italy
| | - Emilia Bellone
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health, Section of Medical Genetics, University of Genoa, Genoa, Italy.,COU Medical Genetics, IRCCS AOU San Martino IST-Istituto Nazionale per la Ricerca sul Cancro, Genoa, Italy
| | - Vincent Timmerman
- VIB Department of Molecular Genetics, Peripheral Neuropathy Group, Born Bunge Foundation, University of Antwerp, Antwerp, Belgium.
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Rotella C, Kilpatrick JI, Capponi S, Holmgren M, Bezanilla F, Perozo E, Jarvis SP. High Resolution Imaging Atomic Force Microscope Study of Interactions at the Membrane-Fluid Interface. Biophys J 2016. [DOI: 10.1016/j.bpj.2015.11.3103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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10
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Pezzini I, Geroldi A, Capponi S, Gulli R, Schenone A, Grandis M, Doria-Lamba L, La Piana C, Cremonte M, Pisciotta C, Nolano M, Manganelli F, Santoro L, Mandich P, Bellone E. GDAP1 mutations in Italian axonal Charcot–Marie–Tooth patients: Phenotypic features and clinical course. Neuromuscul Disord 2016; 26:26-32. [DOI: 10.1016/j.nmd.2015.09.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 09/02/2015] [Accepted: 09/07/2015] [Indexed: 10/23/2022]
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11
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Yoshida M, Kobayashi H, Yamauchi I, Takigawa M, Capponi S, Poilblanc D, Mila F, Kudo K, Koike Y, Kobayashi N. Real space imaging of spin polarons in Zn-doped SrCu(2)(BO(3))(2). Phys Rev Lett 2015; 114:056402. [PMID: 25699459 DOI: 10.1103/physrevlett.114.056402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Indexed: 06/04/2023]
Abstract
We report on the real space profile of spin polarons in the quasi-two-dimensional frustrated dimer spin system SrCu(2)(BO(3))(2) doped with 0.16% of Zn. The (11)B nuclear magnetic resonance spectrum exhibits 15 additional boron sites near nonmagnetic Zn impurities. With the help of exact diagonalizations of finite clusters, we have deduced from the boron spectrum, the distribution of local magnetizations at the Cu sites with fine spatial resolution, providing direct evidence for an extended spin polaron. The results are confronted with those of other experiments performed on doped and undoped samples of SrCu(2)(BO(3))(2).
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Affiliation(s)
- M Yoshida
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - H Kobayashi
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - I Yamauchi
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - M Takigawa
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - S Capponi
- Laboratoire de Physique Théorique, Université de Toulouse and CNRS, UPS (IRSAMC), F-31062 Toulouse, France
| | - D Poilblanc
- Laboratoire de Physique Théorique, Université de Toulouse and CNRS, UPS (IRSAMC), F-31062 Toulouse, France
| | - F Mila
- Institut de Théorie des Phénomènes Physiques, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - K Kudo
- Department of Physics, Okayama University, Okayama 700-8530, Japan
| | - Y Koike
- Department of Applied Physics, Tohoku University, Sendai 980-8579, Japan
| | - N Kobayashi
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
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12
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Capponi S, Geroldi A, Pezzini I, Gulli R, Ciotti P, Ursino G, Lamp M, Reni L, Schenone A, Grandis M, Mandich P, Bellone E. Contribution of copy number variations in CMT1X: a retrospective study. Eur J Neurol 2015; 22:406-9. [PMID: 24724718 DOI: 10.1111/ene.12434] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 03/06/2014] [Indexed: 11/30/2022]
Abstract
BACKGROUND AND PURPOSE Charcot-Marie-Tooth disease type 1X (CMT1X) is an X-linked dominant hereditary motor-sensory peripheral neuropathy, which results from mutations in the Gap Junction B1 (GJB1) gene. In a few cases, gene deletions have been linked to the disease, but their relative contribution in the pathogenesis of CMT1X has not been assessed yet. Herein a retrospective study to establish the incidence of gene deletions is described. METHODS Copy number variation analysis was performed by multiplex ligation-dependent probe amplification, whilst the breakpoints were defined by Sanger sequencing. RESULTS A novel GJB1 deletion was identified in a family presenting with a classical CMT1X phenotype. The rearrangement includes the coding and the regulatory regions of GJB1. CONCLUSIONS GJB1 deletions appear to be a rare but not insignificant cause of CMT1X and are associated with a typical disease phenotype. Accordingly, patients negative for point mutations whose pedigree and clinical records strongly suggest the possibility of CMT1X should be tested for GJB1 copy number variations.
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Affiliation(s)
- S Capponi
- Section of Medical Genetics, Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health (DINOGMI), University of Genoa, Genoa, Italy
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13
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Manganelli F, Tozza S, Pisciotta C, Bellone E, Iodice R, Nolano M, Geroldi A, Capponi S, Mandich P, Santoro L. Charcot-Marie-Tooth disease: frequency of genetic subtypes in a Southern Italy population. J Peripher Nerv Syst 2014; 19:292-8. [PMID: 25429913 DOI: 10.1111/jns.12092] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 07/09/2014] [Accepted: 09/05/2014] [Indexed: 01/18/2023]
Abstract
The objective of this study is to assess the genetic distribution of Charcot-Marie-Tooth (CMT) disease in Campania, a region of Southern Italy. We analyzed a cohort of 197 index cases and reported the type and frequency of mutations for the whole CMT population and for each electrophysiological group (CMT1, CMT2, and hereditary neuropathy with susceptibility to pressure palsies [HNPP]) and for familial and isolated CMT cases. Genetic diagnosis was achieved in 148 patients (75.1%) with a higher success rate in HNPP and CMT1 than CMT2. Only four genes (PMP22, GJB1, MPZ, and GDAP1) accounted for 92% of all genetically confirmed CMT cases. In CMT1, PMP22 duplication was the most common mutation while the second gene in order of frequency was MPZ in familial and SH3TC2 in isolated cases. In CMT2, GJB1 was the most frequent mutated gene and GJB1 with GDAP1 accounted for almost 3/4 of genetically defined CMT2 patients. The first gene in order of frequency was GJB1 in familial and GDAP1 in isolated cases. In HNPP, the majority of patients harbored the PMP22 gene deletion. The novelty of our data is the relatively high frequency of SH3TC2 and GDAP1 mutations in demyelinating and axonal forms, respectively. These epidemiological data can help in panel design for our patients' population.
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Affiliation(s)
- Fiore Manganelli
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University Federico II of Naples, Naples, Italy
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Prada V, Capponi S, Ursino G, Alberti A, Callegari I, Passalacqua M, Marotta R, Mandich P, Bellone E, Schenone A, Grandis M. Sural nerve biopsy and functional studies support the pathogenic role of a novelMPZmutation. Neuropathology 2014; 35:254-9. [DOI: 10.1111/neup.12179] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 09/30/2014] [Indexed: 01/01/2023]
Affiliation(s)
- Valeria Prada
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal Child Health; Section of Neurology; University of Genova; Genova Italy
| | - Simona Capponi
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal Child Health; Section of Medical Genetics; University of Genova; Genova Italy
| | - Giulia Ursino
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal Child Health; Section of Neurology; University of Genova; Genova Italy
| | - Antonia Alberti
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal Child Health; Section of Neurology; University of Genova; Genova Italy
| | - Ilaria Callegari
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal Child Health; Section of Neurology; University of Genova; Genova Italy
| | - Mario Passalacqua
- Department of Experimental Medicine; Section of Biochemistry; University of Genova; Genova Italy
| | - Roberto Marotta
- Nanochemistry Department; Istituto Italiano di Tecnologia (IIT); Electron Microscopy Facility; Genova Italy
| | - Paola Mandich
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal Child Health; Section of Medical Genetics; University of Genova; Genova Italy
| | - Emilia Bellone
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal Child Health; Section of Medical Genetics; University of Genova; Genova Italy
| | - Angelo Schenone
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal Child Health; Section of Neurology; University of Genova; Genova Italy
| | - Marina Grandis
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal Child Health; Section of Neurology; University of Genova; Genova Italy
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16
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Palmieri D, Capponi S, Geroldi A, Mura M, Mandich P, Palombo D. TNFα induces the expression of genes associated with endothelial dysfunction through p38MAPK-mediated down-regulation of miR-149. Biochem Biophys Res Commun 2014; 443:246-51. [DOI: 10.1016/j.bbrc.2013.11.092] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 11/23/2013] [Indexed: 10/26/2022]
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Napolitano S, Capponi S, Vanroy B. Glassy dynamics of soft matter under 1D confinement: how irreversible adsorption affects molecular packing, mobility gradients and orientational polarization in thin films. Eur Phys J E Soft Matter 2013; 36:61. [PMID: 23797356 DOI: 10.1140/epje/i2013-13061-8] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 05/14/2013] [Accepted: 05/17/2013] [Indexed: 06/02/2023]
Abstract
The structural dynamics of polymers and simple liquids confined at the nanometer scale has been intensively investigated in the last two decades in order to test the validity of theories on the glass transition predicting a characteristic length scale of a few nanometers. Although this goal has not yet been reached, the anomalous behavior displayed by some systems--e.g. thin films of polystyrene exhibit reductions of Tg exceeding 70 K and a tremendous increase in the elastic modulus--has attracted a broad community of researchers, and provided astonishing advancement of both theoretical and experimental soft matter physics. 1D confinement is achieved in thin films, which are commonly treated as systems at thermodynamic equilibrium where free surfaces and solid interfaces introduce monotonous mobility gradients, extending for several molecular sizes. Limiting the discussion to finite-size and interfacial effects implies that film thickness and surface interactions should be sufficient to univocally determine the deviation from bulk behavior. On the contrary, such an oversimplified picture, although intuitive, cannot explain phenomena like the enhancement of segmental mobility in proximity of an adsorbing interface, or the presence of long-lasting metastable states in the liquid state. Based on our recent work, we propose a new picture on the dynamics of soft matter confined in ultrathin films, focusing on non-equilibrium and on the impact of irreversibly chain adsorption on the structural relaxation. We describe the enhancement of dynamics in terms of the excess in interfacial free volume, originating from packing frustration in the adsorbed layer (Guiselin brush) at t(*) ≪ 1, where t(*) is the ratio between the annealing time and the time scale of adsorption. Prolonged annealing at times exceeding the reptation time (usually t(*) ≫ 1 induces densification, and thus reduces the deviation from bulk behavior. In this Colloquium, after reviewing the experimental approaches permitting to investigate the structural relaxation of films with one, two or no free surfaces by means of dielectric spectroscopy, we propose several methods to determine gradients of mobility in thin films, and then discuss on the unexploited potential of analyses based on the time, temperature and thickness dependence of the orientational polarization via the dielectric strength.
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Affiliation(s)
- Simone Napolitano
- Laboratory of Polymer and Soft Matter Dynamics, Faculté des Sciences, Université Libre de Bruxelles, Boulevard du Triomphe, Bâtiment NO, 1050, Bruxelles, Belgium.
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Manganelli F, Pisciotta C, Nolano M, Capponi S, Geroldi A, Topa A, Bellone E, Suls A, Mandich P, Santoro L. A novel autosomal dominant GDAP1 mutation in an Italian CMT2 family. J Peripher Nerv Syst 2012; 17:351-5. [DOI: 10.1111/j.1529-8027.2012.00414.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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19
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Prada V, Passalacqua M, Bono M, Luzzi P, Scazzola S, Nobbio LA, Capponi S, Bellone E, Mandich P, Mancardi G, Shy M, Schenone A, Grandis M. Gain of glycosylation: a new pathomechanism of myelin protein zero mutations. Ann Neurol 2012; 71:427-31. [PMID: 22451207 DOI: 10.1002/ana.22695] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We report the first case of a missense mutation in MPZ causing a gain of glycosylation in myelin protein zero, the main protein of peripheral nervous system myelin. The patient was affected by a severe demyelinating neuropathy caused by a missense mutation, D32N, that created a new glycosylation sequence. We confirmed that the mutant protein is hyperglycosylated, is partially retained into the Golgi apparatus in vitro, and disrupts intercellular adhesion. By sequential experiments, we demonstrated that hyperglycosylation is the main mechanism of this mutation. Gain of glycosylation is a new mechanism in Charcot-Marie-Tooth type 1B.
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Affiliation(s)
- Valeria Prada
- Department of Neurosciences, Ophthalmology, and Genetics, University of Genoa, Genoa, Italy
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Capponi S, Geroldi A, Fossa P, Grandis M, Ciotti P, Gulli R, Schenone A, Mandich P, Bellone E. HSPB1 and HSPB8 in inherited neuropathies: study of an Italian cohort of dHMN and CMT2 patients. J Peripher Nerv Syst 2012; 16:287-94. [PMID: 22176143 DOI: 10.1111/j.1529-8027.2011.00361.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Mutations in the small heat-shock protein 27 kDa protein 1 (HSPB1) and 22 kDa protein 8 (HSPB8) genes were associated with distal hereditary motor neuropathy (dHMN) and with the axonal form of Charcot-Marie-Tooth disease type 2 (CMT2). Here we report the clinical and molecular evaluation of an Italian dHMN and CMT2 cohort to establish HSPB1 and HSPB8 mutation occurrence and associated clinical features. One hundred and sixty-seven patients with dHMN or CMT2 were studied. HSPB1 and HSPB8 exons 1 and 3 molecular analysis was carried out through DHPLC and direct sequencing of each variant chromatogram. HSPB8 exon 2 was analyzed by direct sequencing. Four mutations in five unrelated dHMN patients and four mutations in four unrelated CMT2 cases were found in HSPB1. The p.Arg136Leu mutation was found in two patients with different phenotypes. Electroneurographical follow-up study in a dHMN patient revealed that sensory impairment occurred with disease progression. The HSPB1 mutation frequency was 8% in dHMN and 4% in CMT2 patients. The significant HSPB1 mutation frequency in both phenotypes indicates its relevance in the pathogenesis of these neuropathies. Recent literature data suggest a continuum between dHMN and CMT2. We confirm this finding in our cohort, proposing a definite relationship between these disorders.
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Affiliation(s)
- Simona Capponi
- Department of Neuroscience, Ophthalmology and Genetics-Section of Medical Genetics, University of Genoa, Genoa, Italy
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Capponi S, Arbe A, Cerveny S, Busselez R, Frick B, Embs JP, Colmenero J. Quasielastic neutron scattering study of hydrogen motions in an aqueous poly(vinyl methyl ether) solution. J Chem Phys 2011; 134:204906. [PMID: 21639476 DOI: 10.1063/1.3592560] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present a quasielastic neutron scattering (QENS) investigation of the component dynamics in an aqueous Poly(vinyl methyl ether) (PVME) solution (30% water content in weight). In the glassy state, an important shift in the Boson peak of PVME is found upon hydration. At higher temperatures, the diffusive-like motions of the components take place with very different characteristic times, revealing a strong dynamic asymmetry that increases with decreasing T. For both components, we observe stretching of the scattering functions with respect to those in the bulk and non-Gaussian behavior in the whole momentum transfer range investigated. To explain these observations we invoke a distribution of mobilities for both components, probably originated from structural heterogeneities. The diffusive-like motion of PVME in solution takes place faster and apparently in a more continuous way than in bulk. We find that the T-dependence of the characteristic relaxation time of water changes at T ≲ 225 K, near the temperature where a crossover from a low temperature Arrhenius to a high temperature cooperative behavior has been observed by broadband dielectric spectroscopy (BDS) [S. Cerveny, J. Colmenero and A. Alegría, Macromolecules, 38, 7056 (2005)]. This observation might be a signature of the onset of confined dynamics of water due to the freezing of the PVME dynamics, that has been selectively followed by these QENS experiments. On the other hand, revisiting the BDS results on this system we could identify an additional "fast" process that can be attributed to water motions coupled with PVME local relaxations that could strongly affect the QENS results. Both kinds of interpretations, confinement effects due to the increasing dynamic asymmetry and influence of localized motions, could provide alternative scenarios to the invoked "strong-to-fragile" transition.
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Affiliation(s)
- S Capponi
- Donostia International Physics Center, Paseo Manuel de Lardizabal 4, 20018 San Sebastián, Spain.
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Račko D, Capponi S, Alvarez F, Colmenero J. The free volume of poly(vinyl methylether) as computed in a wide temperature range and at length scales up to the nanoregion. J Chem Phys 2011; 134:044512. [PMID: 21280753 DOI: 10.1063/1.3525380] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In the present work, we focus on the free volume evaluations from different points of view, including the aspect of probe sizes, temperature, and cavity threshold. The free volume structure is analyzed on structures of poly(vinyl methylether) prepared by fully atomistic molecular dynamics. At first, the temperature behavior of an overall free volume and a free volume separated into individual cavities is shown. The origin of large free volume cavities is explained. A complex view on the cavity number is provided, while a complicated behavior previously observed is now explained. The number of large cavities remained almost constant with the temperature. Oppositely, the number of small cavities related to the atomic packing changes with temperature in a distinct way for glassy and supercooled regions. The cavity number maxima determine a percolation threshold according to percolation theory. The change in polymer properties with temperature can be related to a percolation of the free volume according to the free volume theory, when proper probe radii ∼0.8 Å are used for its observation. A construction of probabilistic distribution of free volume sizes is suggested. The free volume distributions reported here are bimodal. The bimodal character is explained by two different packings--atomic and segmental--forming a prepeak and a main peak on the distribution. Further attention is dedicated to comparisons of the computed free volume sizes and the ortho-positronium (o-Ps) lifetimes. The prepeak of the free volume distribution is probably unseen by o-Ps because of a cavity threshold limit. The effect of the shape factor on the computed o-Ps lifetimes is tested. The quasicavities obtained by redistributing the free volume maintain the ratio of the main dimensions with temperature. Finally, novel data on the cavity environment are provided, while it is suggested how these can be useful with the recent developments in the positron annihilation methods. The coordination number of large cavities with the polymer segments is around 1, as predicted in the free volume theory. Similarly to the percolation and the cavity number, the coordination number exhibits a change when explored by a suitable probe radius ∼0.8 Å. The insightful visualizations showed properties of interest investigated within the actual work.
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Affiliation(s)
- Dušan Račko
- Donostia International Physics Center, Paseo de Manuel Lardizabal 4, 20018 Donostia-San Sebastián, Spain.
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Capponi S, Arbe A, Alvarez F, Colmenero J, Frick B, Embs JP. Atomic motions in poly(vinyl methyl ether): A combined study by quasielastic neutron scattering and molecular dynamics simulations in the light of the mode coupling theory. J Chem Phys 2009; 131:204901. [DOI: 10.1063/1.3258857] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Mandich P, Fossa P, Capponi S, Geroldi A, Acquaviva M, Gulli R, Ciotti P, Manganelli F, Grandis M, Bellone E. Clinical features and molecular modelling of novel MPZ mutations in demyelinating and axonal neuropathies. Eur J Hum Genet 2009; 17:1129-34. [PMID: 19293842 DOI: 10.1038/ejhg.2009.37] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Mutations in the myelin protein zero (MPZ) gene have been associated with different Charcot-Marie-Tooth disease (CMT) phenotypes, including classical demyelinating CMT1B and the axonal form of the disease (CMT2). The MPZ role in the pathogenesis of both demyelinating and axonal inherited neuropathies was evaluated in the Italian population by screening a cohort of 214 patients with CMT1 or CMT2. A MPZ mutation frequency of 7.9% in demyelinating cases and of 4.8% in axonal cases was observed. In the total cohort (264 patients), including those with mutations in other genes, a mutation frequency of 5.8% (7/121) in demyelinating cases and 4.2% (6/143) in axonal cases was found. Three novel MPZ mutations, two missense (p.Ser111Cys, p.Thr124Ala) and one frameshift (p.Tyr145fs) were found, and a molecular modelling approach was used to test the effects of these mutations on the protein structure. Electrostatic distribution changes within the protein, caused by the amino acid substitution, fit in with phenotypes presented by patients herein described. Our findings suggest that the clinical features associated with MPZ mutations depend partly on the nature of amino acid change and that molecular modelling may provide useful support, based on effects on secondary and tertiary protein structure, to predict the phenotype associated with MPZ mutations.
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Affiliation(s)
- Paola Mandich
- Department of Neuroscience, Ophthalmology and Genetics, University of Genoa, Genoa, Italy.
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Rüegg C, Kiefer K, Thielemann B, McMorrow DF, Zapf V, Normand B, Zvonarev MB, Bouillot P, Kollath C, Giamarchi T, Capponi S, Poilblanc D, Biner D, Krämer KW. Thermodynamics of the spin Luttinger liquid in a model ladder material. Phys Rev Lett 2008; 101:247202. [PMID: 19113659 DOI: 10.1103/physrevlett.101.247202] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Revised: 10/24/2008] [Indexed: 05/27/2023]
Abstract
The phase diagram in temperature and magnetic field of the metal-organic, two-leg, spin-ladder compound (C5H12N)2CuBr4 is studied by measurements of the specific heat and the magnetocaloric effect. We demonstrate the presence of an extended spin Luttinger-liquid phase between two field-induced quantum critical points and over a broad range of temperature. Based on an ideal spin-ladder Hamiltonian, comprehensive numerical modeling of the ladder specific heat yields excellent quantitative agreement with the experimental data across the entire phase diagram.
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Affiliation(s)
- Ch Rüegg
- London Centre for Nanotechnology, University College London, London WC1E 6BT, United Kingdom
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Abendschein A, Capponi S. Effective theory of magnetization plateaux in the Shastry-Sutherland lattice. Phys Rev Lett 2008; 101:227201. [PMID: 19113516 DOI: 10.1103/physrevlett.101.227201] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Indexed: 05/27/2023]
Abstract
We use the nonperturbative Contractor-Renormalization method (CORE) in order to derive an effective model for triplet excitations on the Shastry-Sutherland lattice. For strong enough magnetic fields, various magnetization plateaux are observed, e.g., at 1/8, 1/4, 1/3 of the saturation, as found experimentally in a related compound. Moreover, other stable plateaux are found at 1/9, 1/6, or 2/9. We give a critical review of previous works and try to resolve some apparent inconsistencies between various theoretical approaches.
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Affiliation(s)
- A Abendschein
- Laboratoire de Physique Théorique, Université de Toulouse, UPS, IRSAMC, F-31062 Toulouse, France
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Ostaci RV, Damiron D, Capponi S, Vignaud G, Léger L, Grohens Y, Drockenmuller E. Polymer brushes grafted to "passivated" silicon substrates using click chemistry. Langmuir 2008; 24:2732-2739. [PMID: 18247640 DOI: 10.1021/la703086x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We present herein a versatile method for grafting polymer brushes to passivated silicon surfaces based on the Cu(I)-catalyzed Huisgen 1,3-dipolar cycloaddition (click chemistry) of omega-azido polymers and alkynyl-functionalized silicon substrates. First, the "passivation" of the silicon substrates toward polymer adsorption was performed by the deposition of an alkyne functionalized self-assembled monolayer (SAM). Then, three tailor-made omega-azido linear brush precursors, i.e., PEG-N3, PMMA-N3, and PS-N3 (Mn approximately 20,000 g/mol), were grafted to alkyne-functionalized SAMs via click chemistry in tetrahydrofuran. The SAM, PEG, PMMA, and PS layers were characterized by ellipsometry, scanning probe microscopy, and water contact angle measurements. Results have shown that the grafting process follows the scaling laws developed for polymer brushes, with a significant dependence over the weight fraction of polymer in the grafting solution and the grafting time. The chemical nature of the brushes has only a weak influence on the click chemistry grafting reaction and morphologies observed, yielding polymer brushes with thickness of ca. 6 nm and grafting densities of ca. 0.2 chains/nm2. The examples developed herein have shown that this highly versatile and tunable approach can be extended to the grafting of a wide range of polymer (pseudo-) brushes to silicon substrates without changing the tethering strategy.
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Affiliation(s)
- Roxana-Viorela Ostaci
- Université Claude Bernard Lyon 1, Laboratoire des Matériaux Polymères et Biomatériaux (IMP/LMPB, UMR CNRS 5223), 15 Boulevard Latarjet, 69622 Villeurbanne Cedex, France
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Cornicchi E, Capponi S, Marconi M, Onori G, Paciaroni A. Thermal fluctuations of DNA enclosed by glycerol–water glassy matrices: an elastic neutron scattering investigation. Eur Biophys J 2008; 37:583-90. [DOI: 10.1007/s00249-008-0268-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2007] [Revised: 12/28/2007] [Accepted: 01/08/2008] [Indexed: 11/25/2022]
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Brünger C, Assaad FF, Capponi S, Alet F, Aristov DN, Kiselev MN. Spin gap and string order parameter in the ferromagnetic spiral staircase heisenberg ladder: a quantum Monte Carlo study. Phys Rev Lett 2008; 100:017202. [PMID: 18232811 DOI: 10.1103/physrevlett.100.017202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Indexed: 05/25/2023]
Abstract
We consider a spin-1/2 ladder with a ferromagnetic rung coupling J perpendicular and inequivalent chains. This model is obtained by a twist (theta) deformation of the ladder and interpolates between the isotropic ladder (theta=0) and the SU(2) ferromagnetic Kondo necklace model (theta = pi). We show that the ground state in the (theta, J perpendicular) plane has a finite string order parameter characterizing the Haldane phase. Twisting the chain introduces a new energy scale, which we interpret in terms of a Suhl-Nakamura interaction. As a consequence we observe a crossover in the scaling of the spin gap at weak coupling from delta/J parallel proportional, variant J perpendicular/J parallel for theta < theta c approximately 8 pi/9 to delta/J parallel proportional, variant (J perpendicular/J parallel)2 for theta > theta c. Those results are obtained on the basis of large scale quantum Monte Carlo calculations.
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Affiliation(s)
- C Brünger
- Institut für Theoretische Physik, Universität Würzburg, D-97074 Würzburg, Germany
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Roux G, White SR, Capponi S, Poilblanc D. Zeeman effect in superconducting two-leg ladders: irrational magnetization plateaus and exceeding the Pauli limit. Phys Rev Lett 2006; 97:087207. [PMID: 17026332 DOI: 10.1103/physrevlett.97.087207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2005] [Indexed: 05/12/2023]
Abstract
The effect of a parallel magnetic field on superconducting two-leg ladders is investigated numerically. The magnetization curve displays an irrational plateau at a magnetization equal to the hole density. Remarkably, its stability is fundamentally connected to the existence of a well-known magnetic resonant mode. Once the zero-field spin gap is suppressed by the field, pairs acquire a finite momentum characteristic of a Fulde-Ferrell-Larkin-Ovchinnikov phase. In addition, Sz = 0 triplet superconducting correlations coexist with singlet ones above the irrational plateau. This provides a simple mechanism in which the Pauli limit is exceeded as suggested by recent experiments.
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Affiliation(s)
- G Roux
- Laboratoire de Physique Théorique, UMR5152 Université Paul Sabatier, 31062 Toulouse, France.
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Abstract
Using a newly developed hybrid Monte Carlo algorithm for the nearest-neighbor (nn) t-J model, we show that antiholons identified in the supersymmetric inverse squared (IS) t-J model are clearly visible in the electron-addition spectrum of the nn t-J model at J=2t and also for J=0.5t, a value of experimental relevance.
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Affiliation(s)
- C Lavalle
- Institut für Theoretische Physik III, Universität Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart, Germany
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Capponi S, Poilblanc D, Mila F. Confinement and transverse conductivity in coupled Luttinger liquids. Phys Rev B Condens Matter 1996; 54:17547-17556. [PMID: 9985878 DOI: 10.1103/physrevb.54.17547] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Poilblanc D, Endres H, Mila F, Zacher MG, Capponi S, Hanke W. One-particle interchain hopping in coupled Hubbard chains. Phys Rev B Condens Matter 1996; 54:10261-10264. [PMID: 9984798 DOI: 10.1103/physrevb.54.10261] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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