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Thompson CH, Potet F, Abramova TV, DeKeyser JM, Ghabra NF, Vanoye CG, Millichap JJ, George AL. Epilepsy-associated SCN2A (NaV1.2) variants exhibit diverse and complex functional properties. J Gen Physiol 2023; 155:e202313375. [PMID: 37578743 PMCID: PMC10424433 DOI: 10.1085/jgp.202313375] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 06/29/2023] [Accepted: 07/25/2023] [Indexed: 08/15/2023] Open
Abstract
Pathogenic variants in voltage-gated sodium (NaV) channel genes including SCN2A, encoding NaV1.2, are discovered frequently in neurodevelopmental disorders with or without epilepsy. SCN2A is also a high-confidence risk gene for autism spectrum disorder (ASD) and nonsyndromic intellectual disability (ID). Previous work to determine the functional consequences of SCN2A variants yielded a paradigm in which predominantly gain-of-function variants cause neonatal-onset epilepsy, whereas loss-of-function variants are associated with ASD and ID. However, this framework was derived from a limited number of studies conducted under heterogeneous experimental conditions, whereas most disease-associated SCN2A variants have not been functionally annotated. We determined the functional properties of SCN2A variants using automated patch-clamp recording to demonstrate the validity of this method and to examine whether a binary classification of variant dysfunction is evident in a larger cohort studied under uniform conditions. We studied 28 disease-associated variants and 4 common variants using two alternatively spliced isoforms of NaV1.2 expressed in HEK293T cells. Automated patch-clamp recording provided a valid high throughput method to ascertain detailed functional properties of NaV1.2 variants with concordant findings for variants that were previously studied using manual patch clamp. Many epilepsy-associated variants in our study exhibited complex patterns of gain- and loss-of-functions that are difficult to classify by a simple binary scheme. The higher throughput achievable with automated patch clamp enables study of variants with greater standardization of recording conditions, freedom from operator bias, and enhanced experimental rigor. This approach offers an enhanced ability to discern relationships between channel dysfunction and neurodevelopmental disorders.
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Affiliation(s)
- Christopher H. Thompson
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Franck Potet
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Tatiana V. Abramova
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Jean-Marc DeKeyser
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Nora F. Ghabra
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Carlos G. Vanoye
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - John J. Millichap
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Alfred L. George
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
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2
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Thompson CH, Potet F, Abramova TV, DeKeyser JM, Ghabra NF, Vanoye CG, Millichap J, George AL. Epilepsy-associated SCN2A (Na V 1.2) Variants Exhibit Diverse and Complex Functional Properties. bioRxiv 2023:2023.02.23.529757. [PMID: 36865317 PMCID: PMC9980081 DOI: 10.1101/2023.02.23.529757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Abstract
Pathogenic variants in neuronal voltage-gated sodium (Na V ) channel genes including SCN2A , which encodes Na V 1.2, are frequently discovered in neurodevelopmental disorders with and without epilepsy. SCN2A is also a high confidence risk gene for autism spectrum disorder (ASD) and nonsyndromic intellectual disability (ID). Previous work to determine the functional consequences of SCN2A variants yielded a paradigm in which predominantly gain-of-function (GoF) variants cause epilepsy whereas loss-of-function (LoF) variants are associated with ASD and ID. However, this framework is based on a limited number of functional studies conducted under heterogenous experimental conditions whereas most disease-associated SCN2A variants have not been functionally annotated. We determined the functional properties of more than 30 SCN2A variants using automated patch clamp recording to assess the analytical validity of this approach and to examine whether a binary classification of variant dysfunction is evident in a larger cohort studied under uniform conditions. We studied 28 disease-associated variants and 4 common population variants using two distinct alternatively spliced forms of Na V 1.2 that were heterologously expressed in HEK293T cells. Multiple biophysical parameters were assessed on 5,858 individual cells. We found that automated patch clamp recording provided a valid high throughput method to ascertain detailed functional properties of Na V 1.2 variants with concordant findings for a subset of variants that were previously studied using manual patch clamp. Additionally, many epilepsy-associated variants in our study exhibited complex patterns of gain- and loss-of-function properties that are difficult to classify overall by a simple binary scheme. The higher throughput achievable with automated patch clamp enables study of a larger number of variants, greater standardization of recording conditions, freedom from operator bias, and enhanced experimental rigor valuable for accurate assessment of Na V channel variant dysfunction. Together, this approach will enhance our ability to discern relationships between variant channel dysfunction and neurodevelopmental disorders.
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Affiliation(s)
- Christopher H Thompson
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 USA
| | - Franck Potet
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 USA
| | - Tatiana V Abramova
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 USA
| | - Jean-Marc DeKeyser
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 USA
| | - Nora F Ghabra
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 USA
| | - Carlos G Vanoye
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 USA
| | - John Millichap
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 USA
| | - Alfred L George
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 USA
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3
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Fetterman KA, Blancard M, Jouni M, Potet F, Webster GG, George AL, Burridge PW. Abstract P2105: Precision Medicine In Pediatric Calmodulinopathy. Circ Res 2022. [DOI: 10.1161/res.131.suppl_1.p2105] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Calmodulinopathy is a life-threatening cardiac arrhythmia syndrome resulting from a single heterozygous mutation in any of the three calmodulin (CaM) genes. Most (68%) persons with a pathogenic CaM variant will experience a major arrhythmic event such as aborted cardiac arrest or sudden cardiac death by the age of five years. Calmodulinopathies result in heterogenous clinical features with one of the predominant clinical phenotypes being long QT syndrome (CaM-LQTS). Despite current treatments, 56% of calmodulinopathy patients experience breakthrough cardiac events, underscoring the need for improved therapeutics. A current barrier to effective treatment is our incomplete understanding of how calmodulin genetic variants contribute to pathological phenotypes. Human induced pluripotent stem cells (hiPSCs) can be differentiated into cardiomyocytes (hiPSC-CMs) while maintaining the patient’s genetic background. Application of hiPSC-CMs in the context of this disease allows us to better understand patient-specific heterogeneity at the cellular level. We have established a CaM-LQTS hiPSC-CM model using hiPSCs generated from five persons with a pathogenic CaM variant who present with CaM-LQTS. We hypothesize that we can model a CaM-LQTS phenotype using patient-specific hiPSC-CMs, identify clinically appropriate drugs that correct it, and determine underlying mechanisms that drive this phenotype. We have determined the cellular CaM-LQTS phenotype of each patient line using blinded electrophysiological, contractility, and calcium imaging studies and have identified FDA-approved drugs that alleviate these phenotypes. We are also performing experiments, with a focus on calcium cycling dysregulation, to identify underlying mechanisms that drive the cellular CaM-LQTS phenotype. In conclusion, these studies will provide a patient-specific methodology to identify necessary clinical treatments for CaM-LQTS and elucidate the drivers of this rare and severe disease.
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4
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Pournamdari A, Wang J, Nguyen TP, George A, Potet F. NOVEL SCN5A MUTATION ASSOCIATED WITH LETHAL DRUG RESISTANT LONG QT SYNDROME. J Am Coll Cardiol 2022. [DOI: 10.1016/s0735-1097(22)03512-4] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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5
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Barc J, Tadros R, Glinge C, Chiang DY, Jouni M, Simonet F, Jurgens SJ, Baudic M, Nicastro M, Potet F, Offerhaus JA, Walsh R, Choi SH, Verkerk AO, Mizusawa Y, Anys S, Minois D, Arnaud M, Duchateau J, Wijeyeratne YD, Muir A, Papadakis M, Castelletti S, Torchio M, Ortuño CG, Lacunza J, Giachino DF, Cerrato N, Martins RP, Campuzano O, Van Dooren S, Thollet A, Kyndt F, Mazzanti A, Clémenty N, Bisson A, Corveleyn A, Stallmeyer B, Dittmann S, Saenen J, Noël A, Honarbakhsh S, Rudic B, Marzak H, Rowe MK, Federspiel C, Le Page S, Placide L, Milhem A, Barajas-Martinez H, Beckmann BM, Krapels IP, Steinfurt J, Winkel BG, Jabbari R, Shoemaker MB, Boukens BJ, Škorić-Milosavljević D, Bikker H, Manevy FC, Lichtner P, Ribasés M, Meitinger T, Müller-Nurasyid M, Veldink JH, van den Berg LH, Van Damme P, Cusi D, Lanzani C, Rigade S, Charpentier E, Baron E, Bonnaud S, Lecointe S, Donnart A, Le Marec H, Chatel S, Karakachoff M, Bézieau S, London B, Tfelt-Hansen J, Roden D, Odening KE, Cerrone M, Chinitz LA, Volders PG, van de Berg MP, Laurent G, Faivre L, Antzelevitch C, Kääb S, Arnaout AA, Dupuis JM, Pasquie JL, Billon O, Roberts JD, Jesel L, Borggrefe M, Lambiase PD, Mansourati J, Loeys B, Leenhardt A, Guicheney P, Maury P, Schulze-Bahr E, Robyns T, Breckpot J, Babuty D, Priori SG, Napolitano C, de Asmundis C, Brugada P, Brugada R, Arbelo E, Brugada J, Mabo P, Behar N, Giustetto C, Molina MS, Gimeno JR, Hasdemir C, Schwartz PJ, Crotti L, McKeown PP, Sharma S, Behr ER, Haissaguerre M, Sacher F, Rooryck C, Tan HL, Remme CA, Postema PG, Delmar M, Ellinor PT, Lubitz SA, Gourraud JB, Tanck MW, George AL, MacRae CA, Burridge PW, Dina C, Probst V, Wilde AA, Schott JJ, Redon R, Bezzina CR. Genome-wide association analyses identify new Brugada syndrome risk loci and highlight a new mechanism of sodium channel regulation in disease susceptibility. Nat Genet 2022; 54:232-239. [PMID: 35210625 DOI: 10.1038/s41588-021-01007-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 12/13/2021] [Indexed: 12/19/2022]
Abstract
Brugada syndrome (BrS) is a cardiac arrhythmia disorder associated with sudden death in young adults. With the exception of SCN5A, encoding the cardiac sodium channel NaV1.5, susceptibility genes remain largely unknown. Here we performed a genome-wide association meta-analysis comprising 2,820 unrelated cases with BrS and 10,001 controls, and identified 21 association signals at 12 loci (10 new). Single nucleotide polymorphism (SNP)-heritability estimates indicate a strong polygenic influence. Polygenic risk score analyses based on the 21 susceptibility variants demonstrate varying cumulative contribution of common risk alleles among different patient subgroups, as well as genetic associations with cardiac electrical traits and disorders in the general population. The predominance of cardiac transcription factor loci indicates that transcriptional regulation is a key feature of BrS pathogenesis. Furthermore, functional studies conducted on MAPRE2, encoding the microtubule plus-end binding protein EB2, point to microtubule-related trafficking effects on NaV1.5 expression as a new underlying molecular mechanism. Taken together, these findings broaden our understanding of the genetic architecture of BrS and provide new insights into its molecular underpinnings.
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Affiliation(s)
- Julien Barc
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France. .,European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart, .
| | - Rafik Tadros
- Department of Clinical and Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Department of Medicine, Cardiovascular Genetics Center, Montreal Heart Institute and Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Charlotte Glinge
- Department of Clinical and Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,The Department of Cardiology, The Heart Centre, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - David Y Chiang
- Medicine, Cardiovascular Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - Mariam Jouni
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Floriane Simonet
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France
| | - Sean J Jurgens
- The Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Manon Baudic
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France
| | - Michele Nicastro
- Department of Clinical and Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Franck Potet
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Joost A Offerhaus
- Department of Clinical and Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Roddy Walsh
- Department of Clinical and Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | | | - Arie O Verkerk
- Department of Clinical and Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Department of Medical Biology, University of Amsterdam, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Yuka Mizusawa
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart.,Department of Clinical and Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Soraya Anys
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France
| | - Damien Minois
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France
| | - Marine Arnaud
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France
| | - Josselin Duchateau
- IHU Liryc, Electrophysiology and Heart Modeling Institute, fondation Bordeaux Université, Pessac-Bordeaux, France.,Université Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France.,INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France.,Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), Pessac, France
| | - Yanushi D Wijeyeratne
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart.,Molecular and Clinical Sciences Research Institute, St. George's, University of London, London, UK.,Cardiology Clinical Academic Group, St. George's University Hospitals' NHS Foundation Trust, London, UK
| | - Alison Muir
- Cardiology, Belfast Health and Social Care Trust and Queen's University Belfast, Belfast, UK
| | - Michael Papadakis
- Molecular and Clinical Sciences Research Institute, St. George's, University of London, London, UK.,Cardiology Clinical Academic Group, St. George's University Hospitals' NHS Foundation Trust, London, UK
| | - Silvia Castelletti
- Center for Cardiac Arrhythmias of Genetic Origin, Istituto Auxologico Italiano IRCCS, Milan, Italy
| | - Margherita Torchio
- Laboratory of Cardiovascular Genetics, Istituto Auxologico Italiano IRCCS, Cusano Milanino, Italy
| | - Cristina Gil Ortuño
- Cardiogenetic, Unidad de Cardiopatías Familiares, Instituto Murciano de Investigación Biosanitaria, Universidad de Murcia, Murcia, Spain
| | - Javier Lacunza
- Cardiology, Unidad de Cardiopatías Familiares, Hospital Universitario Virgen de la Arrixaca, Universidad de Murcia, Murcia, Spain
| | - Daniela F Giachino
- Clinical and Biological Sciences, Medical Genetics, University of Torino, Orbassano, Italy.,Medical Genetics, San Luigi Gonzaga University Hospital, Orbassano, Italy
| | - Natascia Cerrato
- Medical Sciences, Cardiology, University of Torino, Torino, Italy
| | - Raphaël P Martins
- Cardiologie et Maladies vasculaires, Université Rennes1 - CHU Rennes, Rennes, France
| | - Oscar Campuzano
- Cardiovascular Genetics Center, University of Girona-IDIBGI, Girona, Spain.,Medical Science Department, University of Girona, Girona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain.,Biochemistry and Molecular Genetics Department, Hospital Clinic, University of Barcelona-IDIBAPS, Barcelona, Spain
| | - Sonia Van Dooren
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart.,Centre for Medical Genetics, research group Reproduction and Genetics, research cluster Reproduction, Genetics and Regenerative Medicine, Vrije Universiteit Brussel (VUB), Universitair Ziekenhuis Brussel (UZ Brussel), Brussels, Belgium
| | - Aurélie Thollet
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France
| | - Florence Kyndt
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France
| | - Andrea Mazzanti
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart.,Molecular Cardiology, ICS Maugeri, IRCCS and Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | | | | | - Anniek Corveleyn
- Department of Human Genetics, Catholic University Leuven, Leuven, Belgium
| | - Birgit Stallmeyer
- University Hospital Münster, Institute for Genetics of Heart Diseases (IfGH), Münster, Germany
| | - Sven Dittmann
- University Hospital Münster, Institute for Genetics of Heart Diseases (IfGH), Münster, Germany
| | - Johan Saenen
- Cardiology, Electrophysiology - Cardiogenetics, University of Antwerp/Antwerp University Hospital, Edegem, Belgium
| | - Antoine Noël
- Department of Cardiology, University Hospital of Brest, Brest, France
| | | | - Boris Rudic
- Department 1st of Medicine, Cardiology, University Medical Center Mannheim, Mannheim, Germany.,German Center for Cardiovascular Research (DZHK), Mannheim, Germany
| | - Halim Marzak
- Department of Cardiology, University Hospital of Strasbourg, Strasbourg, France
| | - Matthew K Rowe
- Medicine, Cardiology, Western University, London, Ontario, Canada
| | - Claire Federspiel
- Department of Cardiovascular Medicine, Vendée Hospital, Service de Cardiologie, La Roche sur Yon, France
| | | | - Leslie Placide
- Department of Cardiology, CHU Montpellier, Montpellier, France
| | - Antoine Milhem
- Department of Cardiology, CH La Rochelle, La Rochelle, France
| | | | - Britt-Maria Beckmann
- Department of Medicine I, University Hospital, LMU Munich, Munich, Germany.,University Hospital of the Johann Wolfgang Goethe University Frankfurt, Institute of Legal Medicine, Frankfurt, Germany
| | - Ingrid P Krapels
- Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Johannes Steinfurt
- Department of Cardiology and Angiology I, Heart Center, University Freiburg, Freiburg, Germany
| | - Bo Gregers Winkel
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart.,The Department of Cardiology, The Heart Centre, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Reza Jabbari
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart.,The Department of Cardiology, The Heart Centre, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Moore B Shoemaker
- Medicine, Cardiology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Bas J Boukens
- Department of Medical Biology, University of Amsterdam, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Doris Škorić-Milosavljević
- Department of Clinical and Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Hennie Bikker
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart.,Genome Diagnostics Laboratory, Clinical Genetics, Amsterdam UMC, Amsterdam, The Netherlands
| | - Federico C Manevy
- Department of Clinical and Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Peter Lichtner
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Marta Ribasés
- Psychiatric Genetics Unit, Institute Vall d'Hebron Research (VHIR), Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Thomas Meitinger
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Martina Müller-Nurasyid
- Institute of Genetic Epidemiology, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany.,IBE, LMU Munich, Munich, Germany.,Institute of Medical Biostatistics, Epidemiology and Informatics (IMBEI), University Medical Center, Johannes Gutenberg University, Mainz, Germany.,Department of Internal Medicine I (Cardiology), Hospital of the Ludwig-Maximilians-University (LMU) Munich, Munich, Germany
| | | | - Jan H Veldink
- Department of Neurology, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Leonard H van den Berg
- Department of Neurology, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Philip Van Damme
- Neurology Department University Hospital Leuven, Neuroscience Department KU Leuven, Center for Brain & Disease Research VIB, Leuven, Belgium
| | - Daniele Cusi
- Scientific Unit, Bio4Dreams - Business Nursery for Life Sciences, Milan, Italy
| | - Chiara Lanzani
- Nephrology, Genomics of Renal Diseases and Hypertension Unit, Università Vita Salute San Raffaele, Milan, Italy
| | - Sidwell Rigade
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France
| | - Eric Charpentier
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France.,Université de Nantes, CHU Nantes, Inserm, CNRS, SFR Santé, Inserm UMS 016, CNRS UMS 3556, Nantes, France
| | - Estelle Baron
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France
| | - Stéphanie Bonnaud
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France.,Université de Nantes, CHU Nantes, Inserm, CNRS, SFR Santé, Inserm UMS 016, CNRS UMS 3556, Nantes, France
| | - Simon Lecointe
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France
| | - Audrey Donnart
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France.,Université de Nantes, CHU Nantes, Inserm, CNRS, SFR Santé, Inserm UMS 016, CNRS UMS 3556, Nantes, France
| | - Hervé Le Marec
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France
| | - Stéphanie Chatel
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France
| | - Matilde Karakachoff
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France
| | - Stéphane Bézieau
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France
| | - Barry London
- Department of Internal Medicine, Division of Cardiovascular Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Jacob Tfelt-Hansen
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart.,The Department of Cardiology, The Heart Centre, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,Department of Forensic Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Dan Roden
- Medicine, Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA.,Medicine, Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA.,Medicine, Biomedical Informatics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Katja E Odening
- Department of Cardiology and Angiology I, Heart Center, University Freiburg, Freiburg, Germany.,Department of Cardiology, Translational Cardiology, University Hospital Bern, Bern, Switzerland
| | - Marina Cerrone
- Medicine, Leon H. Charney Division of Cardiology, Heart Rhythm Center and Cardiovascular Genetics Program, New York University School of Medicine, New York, NY, USA
| | - Larry A Chinitz
- Medicine, Leon H. Charney Division of Cardiology, Heart Rhythm Center and Cardiovascular Genetics Program, New York University School of Medicine, New York, NY, USA
| | - Paul G Volders
- Department of Cardiology, CARIM, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Maarten P van de Berg
- Department of Cardiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Gabriel Laurent
- Cardiology Department, ImVia lab team IFTIM, University Hospital Dijon, Dijon, France
| | | | | | - Stefan Kääb
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart.,Department of Medicine I, University Hospital, LMU Munich, Munich, Germany.,German Center for Cardiovascular Research (DZHK), Partnersite Munich, Munich, Germany
| | | | | | - Jean-Luc Pasquie
- Department of Cardiology, CNRS UMR9214 - Inserm U1046 - PHYMEDEXP, Université de Montpellier et CHU Montpellier, Montpellier, France
| | - Olivier Billon
- Department of Cardiovascular Medicine, Vendée Hospital, Service de Cardiologie, La Roche sur Yon, France
| | - Jason D Roberts
- Medicine, Cardiology, Western University, London, Ontario, Canada
| | - Laurence Jesel
- Department of Cardiology, University Hospital of Strasbourg, Strasbourg, France.,INSERM 1260 - Regenerative Nanomedecine, University of Strasbourg, Strasbourg, France
| | - Martin Borggrefe
- Department 1st of Medicine, Cardiology, University Medical Center Mannheim, Mannheim, Germany.,German Center for Cardiovascular Research (DZHK), Mannheim, Germany
| | - Pier D Lambiase
- Cardiology, Medicine, Barts Heart Centre, London, UK.,Institute of Cardiovasculr Science, UCL, Population Health, UCL, London, UK
| | | | - Bart Loeys
- Center for Medical Genetics, Cardiogenetics, University of Antwerp/Antwerp University Hospital, Edegem, Belgium
| | - Antoine Leenhardt
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart.,Department of Cardiology, Hopital Bichat, Paris, France
| | - Pascale Guicheney
- Sorbonne Université, Paris, France.,UMR_S1166, Faculté de médecine, Sorbonne Université, INSERM, Paris, France
| | - Philippe Maury
- Service de cardiologie, Hôpital Rangueil, CHU de Toulouse, Toulouse, France
| | - Eric Schulze-Bahr
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart.,University Hospital Münster, Institute for Genetics of Heart Diseases (IfGH), Münster, Germany
| | - Tomas Robyns
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart.,Cardiovascular Diseases, University Hospitals Leuven, Leuven, Belgium.,Cardiovascular Sciences, University of Leuven, Leuven, Belgium
| | - Jeroen Breckpot
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart.,Department of Human Genetics, Catholic University Leuven, Leuven, Belgium
| | | | - Silvia G Priori
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart.,Molecular Cardiology, ICS Maugeri, IRCCS and Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Carlo Napolitano
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart.,Molecular Cardiology, ICS Maugeri, IRCCS and Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | | | - Carlo de Asmundis
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart.,Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain.,Heart Rhythm Management Center, Postgraduate Program in Cardiac Electrophysiology and Pacing Universitair Ziekenhuis, Brussel-Vrije Universiteit Brussel, ERN Heart Guard Center, Brussels, Belgium.,IDIBAPS, Institut d'Investigació August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Pedro Brugada
- Heart Rhythm Management Center, UZ Brussel-VUB, Brussels, Belgium
| | - Ramon Brugada
- Hospital Trueta, CiberCV, University of Girona, IDIBGI, Girona, Spain, Barcelona, Spain
| | - Elena Arbelo
- Arrhythmia Section, Cardiology Department, Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
| | - Josep Brugada
- Cardiovascular Institute, Hospital Clinic, University of Barcelona, Barcelona, Spain
| | - Philippe Mabo
- Cardiologie et Maladies vasculaires, Université Rennes1 - CHU Rennes, Rennes, France
| | - Nathalie Behar
- Cardiologie et Maladies vasculaires, Université Rennes1 - CHU Rennes, Rennes, France
| | - Carla Giustetto
- Medical Sciences, Cardiology, University of Torino, Torino, Italy
| | - Maria Sabater Molina
- Cardiogenetic, Unidad de Cardiopatías Familiares, Instituto Murciano de Investigación Biosanitaria, Universidad de Murcia, Murcia, Spain
| | - Juan R Gimeno
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart.,Cardiology, Unidad de Cardiopatías Familiares, Hospital Universitario Virgen de la Arrixaca, Universidad de Murcia, Murcia, Spain
| | - Can Hasdemir
- Department of Cardiology, Ege University School of Medicine, Bornova, Turkey
| | - Peter J Schwartz
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart.,Center for Cardiac Arrhythmias of Genetic Origin, Istituto Auxologico Italiano IRCCS, Milan, Italy.,Laboratory of Cardiovascular Genetics, Istituto Auxologico Italiano IRCCS, Cusano Milanino, Italy
| | - Lia Crotti
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart.,Center for Cardiac Arrhythmias of Genetic Origin, Istituto Auxologico Italiano IRCCS, Milan, Italy.,Laboratory of Cardiovascular Genetics, Istituto Auxologico Italiano IRCCS, Cusano Milanino, Italy.,Department of Cardiovascular, Neural and Metabolic Sciences, San Luca Hospital, Istituto Auxologico Italiano IRCCS, Milan, Italy.,Department of Medicine and Surgery, University of Milano-Bicocca, Milan, Italy
| | - Pascal P McKeown
- Cardiology, Belfast Health and Social Care Trust and Queen's University Belfast, Belfast, UK
| | - Sanjay Sharma
- Molecular and Clinical Sciences Research Institute, St. George's, University of London, London, UK.,Cardiology Clinical Academic Group, St. George's University Hospitals' NHS Foundation Trust, London, UK
| | - Elijah R Behr
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart.,Molecular and Clinical Sciences Research Institute, St. George's, University of London, London, UK.,Cardiology Clinical Academic Group, St. George's University Hospitals' NHS Foundation Trust, London, UK
| | - Michel Haissaguerre
- IHU Liryc, Electrophysiology and Heart Modeling Institute, fondation Bordeaux Université, Pessac-Bordeaux, France.,Université Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France.,INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France.,Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), Pessac, France
| | - Frédéric Sacher
- IHU Liryc, Electrophysiology and Heart Modeling Institute, fondation Bordeaux Université, Pessac-Bordeaux, France.,Université Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France.,INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France.,Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), Pessac, France
| | - Caroline Rooryck
- CHU Bordeaux, Service de Génétique Médicale, Bordeaux, France.,Université de Bordeaux, Maladies Rares: Génétique et Métabolisme (MRGM), INSERM U1211, Bordeaux, France
| | - Hanno L Tan
- Department of Clinical and Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Netherlands Heart Institute, Utrecht, The Netherlands
| | - Carol A Remme
- Department of Clinical and Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Pieter G Postema
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart.,Department of Clinical and Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Mario Delmar
- Medicine, Cardiology, New York University School of Medicine, New York, NY, USA
| | - Patrick T Ellinor
- Cardiac Arrhythmia Service and Cardiovascular Research Center, Massachusetts General Hospital and Cardiovascular Disease Initiative, The Broad Institute of MIT and Harvard, Boston, MA, USA
| | - Steven A Lubitz
- Cardiac Arrhythmia Service and Cardiovascular Research Center, Massachusetts General Hospital and Cardiovascular Disease Initiative, The Broad Institute of MIT and Harvard, Boston, MA, USA
| | - Jean-Baptiste Gourraud
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France.,European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart
| | - Michael W Tanck
- Clinical Epidemiology, Biostatistics and Bioinformatics, Clinical Methods and Public Health, Amsterdam Public Health, Amsterdam, The Netherlands
| | - Alfred L George
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.,Center for Pharmacogenomics, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Calum A MacRae
- Medicine, Cardiovascular Medicine, Genetics and Network Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Paul W Burridge
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.,Center for Pharmacogenomics, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Christian Dina
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France
| | - Vincent Probst
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France.,European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart
| | - Arthur A Wilde
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart.,Department of Clinical and Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Jean-Jacques Schott
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France.,European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart
| | - Richard Redon
- Université de Nantes, CHU Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France.,European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart
| | - Connie R Bezzina
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart, . .,Department of Clinical and Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.
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6
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Webster G, Puckelwartz MJ, Pesce LL, Dellefave-Castillo LM, Vanoye CG, Potet F, Page P, Kearns SD, Pottinger T, White S, Arunkumar P, Olson R, Kofman A, Ibrahim N, Ing A, Brew C, Yap KL, Kadri S, George AL, McNally EM. Genomic Autopsy of Sudden Deaths in Young Individuals. JAMA Cardiol 2021; 6:1247-1256. [PMID: 34379075 DOI: 10.1001/jamacardio.2021.2789] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Importance Postmortem genetic testing of young individuals with sudden death has previously identified pathogenic gene variants. However, prior studies primarily considered highly penetrant monogenic variants, often without detailed decedent and family clinical information. Objective To assess genotype and phenotype risk in a diverse cohort of young decedents with sudden death and their families. Design, Setting, and Participants Pathological and whole-genome sequence analysis was conducted in a cohort referred from a national network of medical examiners. Cases were accrued prospectively from May 2015 to March 2019 across 24 US states. Analysis began September 2016 and ended November 2020. Exposures Evaluation of autopsy and clinical data integrated with whole-genome sequence data and family member evaluation. Results A total of 103 decedents (mean [SD] age at death, 23.7 [11.9] years; age range, 1-44 years), their surviving family members, and 140 sex- and genetic ancestry-matched controls were analyzed. Among 103 decedents, autopsy and clinical data review categorized 36 decedents with postmortem diagnoses, 23 decedents with findings of uncertain significance, and 44 with sudden unexplained death. Pathogenic/likely pathogenic (P/LP) genetic variants in arrhythmia or cardiomyopathy genes were identified in 13 decedents (12.6%). A multivariable analysis including decedent phenotype, ancestry, and sex demonstrated that younger decedents had a higher burden of P/LP variants and select variants of uncertain significance (effect size, -1.64; P = .001). These select, curated variants of uncertain significance in cardiac genes were more common in decedents than controls (83 of 103 decedents [86%] vs 100 of 140 controls [71%]; P = .005), and decedents harbored more rare cardiac variants than controls (2.3 variants per individual vs 1.8 in controls; P = .006). Genetic testing of 31 parent-decedent trios and 14 parent-decedent dyads revealed 8 transmitted P/LP variants and 1 de novo P/LP variant. Incomplete penetrance was present in 6 of 8 parents who transmitted a P/LP variant. Conclusions and Relevance Whole-genome sequencing effectively identified P/LP variants in cases of sudden death in young individuals, implicating both arrhythmia and cardiomyopathy genes. Genomic analyses and familial phenotype association suggest potentially additive, oligogenic risk mechanisms for sudden death in this cohort.
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Affiliation(s)
- Gregory Webster
- Division of Cardiology, Department of Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois.,Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Megan J Puckelwartz
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois.,Center for Genetic Medicine, Bluhm Cardiovascular Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Lorenzo L Pesce
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois.,Center for Genetic Medicine, Bluhm Cardiovascular Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Lisa M Dellefave-Castillo
- Center for Genetic Medicine, Bluhm Cardiovascular Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Carlos G Vanoye
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Franck Potet
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Patrick Page
- Center for Genetic Medicine, Bluhm Cardiovascular Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Samuel D Kearns
- Center for Genetic Medicine, Bluhm Cardiovascular Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Tess Pottinger
- Center for Genetic Medicine, Bluhm Cardiovascular Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Steven White
- Cook County Medical Examiner's Office, Chicago, Illinois
| | | | - Rachael Olson
- Division of Cardiology, Department of Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois
| | - Amber Kofman
- Division of Cardiology, Department of Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois
| | - Nora Ibrahim
- Center for Genetic Medicine, Bluhm Cardiovascular Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Alexander Ing
- Northwestern University Feinberg School of Medicine, Chicago, Illinois.,Department of Pathology, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois
| | - Casey Brew
- Northwestern University Feinberg School of Medicine, Chicago, Illinois.,Department of Pathology, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois
| | - Kai Lee Yap
- Northwestern University Feinberg School of Medicine, Chicago, Illinois.,Department of Pathology, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois
| | - Sabah Kadri
- Northwestern University Feinberg School of Medicine, Chicago, Illinois.,Department of Pathology, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois
| | - Alfred L George
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Elizabeth M McNally
- Center for Genetic Medicine, Bluhm Cardiovascular Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois.,Section Editor, JAMA Cardiology
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7
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Marchal GA, Jouni M, Chiang DY, Pérez-Hernández M, Podliesna S, Yu N, Casini S, Potet F, Veerman CC, Klerk M, Lodder EM, Mengarelli I, Guan K, Vanoye CG, Rothenberg E, Charpentier F, Redon R, George AL, Verkerk AO, Bezzina CR, MacRae CA, Burridge PW, Delmar M, Galjart N, Portero V, Remme CA. Targeting the Microtubule EB1-CLASP2 Complex Modulates Na V1.5 at Intercalated Discs. Circ Res 2021; 129:349-365. [PMID: 34092082 PMCID: PMC8298292 DOI: 10.1161/circresaha.120.318643] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Gerard A Marchal
- Department of Experimental Cardiology, Amsterdam UMC - location AMC, The Netherlands (G.A.M., S.P., S.C., C.C.V., E.M.L., I.M., A.O.V., C.R.B., V.P., C.A.R.)
| | - Mariam Jouni
- Department of Pharmacology, University Feinberg School of Medicine, Chicago, IL (M.J., F.P., C.G.V., A.L.G., P.W.B.)
| | - David Y Chiang
- Brigham and Women's Hospital and Harvard Medical School, Boston, MA (D.Y.C., C.A.M.)
| | | | - Svitlana Podliesna
- Department of Experimental Cardiology, Amsterdam UMC - location AMC, The Netherlands (G.A.M., S.P., S.C., C.C.V., E.M.L., I.M., A.O.V., C.R.B., V.P., C.A.R.)
| | - Nuo Yu
- Department of Cell Biology, Erasmus Medical Centre Rotterdam, The Netherlands (N.Y., N.G.)
| | - Simona Casini
- Department of Experimental Cardiology, Amsterdam UMC - location AMC, The Netherlands (G.A.M., S.P., S.C., C.C.V., E.M.L., I.M., A.O.V., C.R.B., V.P., C.A.R.)
| | - Franck Potet
- Department of Pharmacology, University Feinberg School of Medicine, Chicago, IL (M.J., F.P., C.G.V., A.L.G., P.W.B.)
| | - Christiaan C Veerman
- Department of Experimental Cardiology, Amsterdam UMC - location AMC, The Netherlands (G.A.M., S.P., S.C., C.C.V., E.M.L., I.M., A.O.V., C.R.B., V.P., C.A.R.)
| | - Mischa Klerk
- Department of Medical Biology, Amsterdam UMC - location AMC, The Netherlands (M.K., A.O.V.)
| | - Elisabeth M Lodder
- Department of Experimental Cardiology, Amsterdam UMC - location AMC, The Netherlands (G.A.M., S.P., S.C., C.C.V., E.M.L., I.M., A.O.V., C.R.B., V.P., C.A.R.)
| | - Isabella Mengarelli
- Department of Experimental Cardiology, Amsterdam UMC - location AMC, The Netherlands (G.A.M., S.P., S.C., C.C.V., E.M.L., I.M., A.O.V., C.R.B., V.P., C.A.R.)
| | - Kaomei Guan
- Institute of Pharmacology and Toxicology, Technische Universität Dresden, Germany (K.G.)
| | - Carlos G Vanoye
- Department of Pharmacology, University Feinberg School of Medicine, Chicago, IL (M.J., F.P., C.G.V., A.L.G., P.W.B.)
| | - Eli Rothenberg
- Department of Biochemistry and Pharmacology (E.R.), NYU School of Medicine
| | - Flavien Charpentier
- Université de Nantes, CNRS, INSERM, l'institut du Thorax, Nantes, France (F.C., R.R., V.P.)
| | - Richard Redon
- Université de Nantes, CNRS, INSERM, l'institut du Thorax, Nantes, France (F.C., R.R., V.P.)
| | - Alfred L George
- Department of Pharmacology, University Feinberg School of Medicine, Chicago, IL (M.J., F.P., C.G.V., A.L.G., P.W.B.)
| | - Arie O Verkerk
- Department of Experimental Cardiology, Amsterdam UMC - location AMC, The Netherlands (G.A.M., S.P., S.C., C.C.V., E.M.L., I.M., A.O.V., C.R.B., V.P., C.A.R.)
- Department of Medical Biology, Amsterdam UMC - location AMC, The Netherlands (M.K., A.O.V.)
| | - Connie R Bezzina
- Department of Experimental Cardiology, Amsterdam UMC - location AMC, The Netherlands (G.A.M., S.P., S.C., C.C.V., E.M.L., I.M., A.O.V., C.R.B., V.P., C.A.R.)
| | - Calum A MacRae
- Brigham and Women's Hospital and Harvard Medical School, Boston, MA (D.Y.C., C.A.M.)
| | - Paul W Burridge
- Department of Pharmacology, University Feinberg School of Medicine, Chicago, IL (M.J., F.P., C.G.V., A.L.G., P.W.B.)
| | - Mario Delmar
- Division of Cardiology (M.P.-H., M.D.), NYU School of Medicine
| | - Niels Galjart
- Department of Cell Biology, Erasmus Medical Centre Rotterdam, The Netherlands (N.Y., N.G.)
| | - Vincent Portero
- Department of Experimental Cardiology, Amsterdam UMC - location AMC, The Netherlands (G.A.M., S.P., S.C., C.C.V., E.M.L., I.M., A.O.V., C.R.B., V.P., C.A.R.)
- Université de Nantes, CNRS, INSERM, l'institut du Thorax, Nantes, France (F.C., R.R., V.P.)
| | - Carol Ann Remme
- Department of Experimental Cardiology, Amsterdam UMC - location AMC, The Netherlands (G.A.M., S.P., S.C., C.C.V., E.M.L., I.M., A.O.V., C.R.B., V.P., C.A.R.)
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8
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Potet F, Egecioglu DE, Burridge PW, George AL. GS-967 and Eleclazine Block Sodium Channels in Human Induced Pluripotent Stem Cell–Derived Cardiomyocytes. Mol Pharmacol 2020; 98:540-547. [DOI: 10.1124/molpharm.120.000048] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 08/24/2020] [Indexed: 11/22/2022] Open
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9
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McKeithan WL, Feyen DAM, Bruyneel AAN, Okolotowicz KJ, Ryan DA, Sampson KJ, Potet F, Savchenko A, Gómez-Galeno J, Vu M, Serrano R, George AL, Kass RS, Cashman JR, Mercola M. Reengineering an Antiarrhythmic Drug Using Patient hiPSC Cardiomyocytes to Improve Therapeutic Potential and Reduce Toxicity. Cell Stem Cell 2020; 27:813-821.e6. [PMID: 32931730 DOI: 10.1016/j.stem.2020.08.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [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: 04/25/2020] [Revised: 06/27/2020] [Accepted: 08/05/2020] [Indexed: 01/05/2023]
Abstract
Modeling cardiac disorders with human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes is a new paradigm for preclinical testing of candidate therapeutics. However, disease-relevant physiological assays can be complex, and the use of hiPSC-cardiomyocyte models of congenital disease phenotypes for guiding large-scale screening and medicinal chemistry have not been shown. We report chemical refinement of the antiarrhythmic drug mexiletine via high-throughput screening of hiPSC-CMs derived from patients with the cardiac rhythm disorder long QT syndrome 3 (LQT3) carrying SCN5A sodium channel variants. Using iterative cycles of medicinal chemistry synthesis and testing, we identified drug analogs with increased potency and selectivity for inhibiting late sodium current across a panel of 7 LQT3 sodium channel variants and suppressing arrhythmic activity across multiple genetic and pharmacological hiPSC-CM models of LQT3 with diverse backgrounds. These mexiletine analogs can be exploited as mechanistic probes and for clinical development.
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Affiliation(s)
- Wesley L McKeithan
- Cardiovascular Institute and Department of Medicine, Stanford University, Stanford, CA 94305, USA; Graduate School of Biomedical Sciences, Sanford Burnham Prebys Medical Discovery Institute, San Diego, CA 92037, USA
| | - Dries A M Feyen
- Cardiovascular Institute and Department of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Arne A N Bruyneel
- Cardiovascular Institute and Department of Medicine, Stanford University, Stanford, CA 94305, USA
| | | | - Daniel A Ryan
- Human BioMolecular Research Institute, San Diego, CA 92121, USA
| | - Kevin J Sampson
- Department of Pharmacology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Franck Potet
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Alex Savchenko
- Cardiovascular Institute and Department of Medicine, Stanford University, Stanford, CA 94305, USA
| | | | - Michelle Vu
- Cardiovascular Institute and Department of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Ricardo Serrano
- Cardiovascular Institute and Department of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Alfred L George
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Robert S Kass
- Department of Pharmacology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - John R Cashman
- Human BioMolecular Research Institute, San Diego, CA 92121, USA
| | - Mark Mercola
- Cardiovascular Institute and Department of Medicine, Stanford University, Stanford, CA 94305, USA; Graduate School of Biomedical Sciences, Sanford Burnham Prebys Medical Discovery Institute, San Diego, CA 92037, USA.
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10
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Bogdanovic E, Potet F, Marszalec W, Iyer H, Galiano R, Hong SJ, Leung KP, Wasserstrom JA, George AL, Mustoe TA. The sodium channel Na X : Possible player in excitation-contraction coupling. IUBMB Life 2020; 72:601-606. [PMID: 32027092 DOI: 10.1002/iub.2247] [Citation(s) in RCA: 3] [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] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 01/18/2020] [Indexed: 11/10/2022]
Abstract
The sodium channel NaX (encoded by the SCN7A gene) was originally identified in the heart and skeletal muscle and is structurally similar to the other voltage-gated sodium channels but does not appear to be voltage gated. Although NaX is expressed at high levels in cardiac and skeletal muscle, little information exists on the function of NaX in these tissues. Transcriptional profiling of ion channels in the heart in a subset of patients with Brugada syndrome revealed an inverse relationship between the expression of NaX and NaV 1.5 suggesting that, in cardiac myocytes, the expression of these channels may be linked. We propose that NaX plays a role in excitation-contraction coupling based on our experimental observations. Here we show that in cardiac myocytes, NaX is expressed in a striated pattern on the sarcolemma in regions corresponding to the sarcomeric M-line. Knocking down NaX expression decreased NaV 1.5 mRNA and protein and reduced the inward sodium current (INa+ ) following cell depolarization. When the expression of NaV 1.5 was knocked down, ~85% of the INa+ was reduced consistent with the observations that NaV 1.5 is the main voltage-gated sodium channel in cardiac muscle and that NaX likely does not directly participate in mediating the INa+ following depolarization. Silencing NaV 1.5 expression led to significant upregulation of NaX mRNA. Similar to NaV 1.5, NaX protein levels were rapidly downregulated when the intracellular [Ca2+ ] was increased either by CaCl2 or caffeine. These data suggest that a relationship exists between NaX and NaV 1.5 and that NaX may play a role in excitation-contraction coupling.
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Affiliation(s)
- Elena Bogdanovic
- Department of Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Franck Potet
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - William Marszalec
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Hari Iyer
- Department of Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Robert Galiano
- Department of Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Seok J Hong
- Department of Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Kai P Leung
- Department of Dental and Maxillofacial Trauma, Institute of Surgical Research, Texas
| | | | - Alfred L George
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Thomas A Mustoe
- Department of Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
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11
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Vanoye CG, Desai RR, Fabre KL, Gallagher SL, Potet F, DeKeyser JM, Macaya D, Meiler J, Sanders CR, George AL. High-Throughput Functional Evaluation of KCNQ1 Decrypts Variants of Unknown Significance. Circ Genom Precis Med 2019; 11:e002345. [PMID: 30571187 DOI: 10.1161/circgen.118.002345] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND The explosive growth in known human gene variation presents enormous challenges to current approaches for variant classification that have implications for diagnosis and treatment of many genetic diseases. For disorders caused by mutations in cardiac ion channels as in congenital arrhythmia syndromes, in vitro electrophysiological evidence has high value in discriminating pathogenic from benign variants, but these data are often lacking because assays are cost, time, and labor intensive. METHODS We implemented a strategy for performing high-throughput functional evaluations of ion channel variants that repurposed an automated electrophysiological recording platform developed previously for drug discovery. RESULTS We demonstrated the success of this approach by evaluating 78 variants in KCNQ1, a major gene involved in genetic disorders of cardiac arrhythmia susceptibility. We benchmarked our results with traditional electrophysiological approaches and observed a high level of concordance. This strategy also enabled studies of dominant-negative behavior of variants exhibiting severe loss-of-function. Overall, our results provided functional data useful for reclassifying >65% of the studied KCNQ1 variants. CONCLUSIONS Our results illustrate an efficient and high-throughput paradigm linking genotype to function for a human cardiac ion channel that will enable data-driven classification of large numbers of variants and create new opportunities for precision medicine.
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Affiliation(s)
- Carlos G Vanoye
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (C.G.V., R.R.D., K.L.F., S.L.G., F.P., J.-M.D., A.L.G.)
| | - Reshma R Desai
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (C.G.V., R.R.D., K.L.F., S.L.G., F.P., J.-M.D., A.L.G.)
| | - Katarina L Fabre
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (C.G.V., R.R.D., K.L.F., S.L.G., F.P., J.-M.D., A.L.G.)
| | - Shannon L Gallagher
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (C.G.V., R.R.D., K.L.F., S.L.G., F.P., J.-M.D., A.L.G.)
| | - Franck Potet
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (C.G.V., R.R.D., K.L.F., S.L.G., F.P., J.-M.D., A.L.G.)
| | - Jean-Marc DeKeyser
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (C.G.V., R.R.D., K.L.F., S.L.G., F.P., J.-M.D., A.L.G.)
| | | | - Jens Meiler
- Department of Chemistry, Vanderbilt University School of Medicine, Nashville, TN (J.M.).,the Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, TN (J.M.,C.R.S.)
| | - Charles R Sanders
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN (C.R.S.).,the Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, TN (J.M.,C.R.S.)
| | - Alfred L George
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (C.G.V., R.R.D., K.L.F., S.L.G., F.P., J.-M.D., A.L.G.)
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Wren LM, Jiménez-Jáimez J, Al-Ghamdi S, Al-Aama JY, Bdeir A, Al-Hassnan ZN, Kuan JL, Foo RY, Potet F, Johnson CN, Aziz MC, Carvill GL, Kaski JP, Crotti L, Perin F, Monserrat L, Burridge PW, Schwartz PJ, Chazin WJ, Bhuiyan ZA, George AL. Genetic Mosaicism in Calmodulinopathy. Circ Genom Precis Med 2019; 12:375-385. [PMID: 31454269 DOI: 10.1161/circgen.119.002581] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
BACKGROUND CaM (calmodulin) mutations are associated with congenital arrhythmia susceptibility (calmodulinopathy) and are most often de novo. In this report, we sought to broaden the genotype-phenotype spectrum of calmodulinopathies with 2 novel calmodulin mutations and to investigate mosaicism in 2 affected families. METHODS CaM mutations were identified in 4 independent cases by DNA sequencing. Biochemical and electrophysiological studies were performed to determine functional consequences of each mutation. RESULTS Genetic studies identified 2 novel CaM variants (CALM3-E141K in 2 cases; CALM1-E141V) and one previously reported CaM pathogenic variant (CALM3-D130G) among 4 probands with shared clinical features of prolonged QTc interval (range 505-725 ms) and documented ventricular arrhythmia. A fatal outcome occurred for 2 of the cases. The parents of all probands were asymptomatic with normal QTc duration. However, 2 of the families had multiple affected offspring or multiple occurrences of intrauterine fetal demise. The mother from the family with recurrent intrauterine fetal demise exhibited the CALM3-E141K mutant allele in 25% of next-generation sequencing reads indicating somatic mosaicism, whereas CALM3-D130G was present in 6% of captured molecules of the paternal DNA sample, also indicating mosaicism. Two novel mutations (E141K and E141V) impaired Ca2+ binding affinity to the C-domain of CaM. Human-induced pluripotent stem cell-derived cardiomyocytes overexpressing mutant or wild-type CaM showed that both mutants impaired Ca2+-dependent inactivation of L-type Ca2+ channels and prolonged action potential duration. CONCLUSIONS We report 2 families with somatic mosaicism associated with arrhythmogenic calmodulinopathy, and demonstrate dysregulation of L-type Ca2+ channels by 2 novel CaM mutations affecting the same residue. Parental mosaicism should be suspected in families with unexplained fetal arrhythmia or fetal demise combined with a documented CaM mutation.
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Affiliation(s)
- Lisa M Wren
- From the Department of Pharmacology (L.M.W., F.P., P.W.B., A.L.G.), Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Juan Jiménez-Jáimez
- Cardiology Department (J.J.-J.), Virgen de las Nieves Hospital, Granada, Spain
| | - Saleh Al-Ghamdi
- Cardiac Sciences Department, Section of Pediatric Cardiology, King Abdulaziz Cardiac Center, Ministry of National Guard Health Affairs, Riyadh (S.A.-G.)
| | - Jumana Y Al-Aama
- Department of Genetic Medicine, Faculty of Medicine (J.Y.A.-A.), King Abdulaziz University, Jeddah.,Princess Al Jawhara Albrahim Center of Excellence in Research of Hereditary Disorders (J.Y.A.-A., A.B.), King Abdulaziz University, Jeddah
| | - Amnah Bdeir
- Princess Al Jawhara Albrahim Center of Excellence in Research of Hereditary Disorders (J.Y.A.-A., A.B.), King Abdulaziz University, Jeddah
| | - Zuhair N Al-Hassnan
- The Cardiovascular Genetics Program, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia (Z.N.A.-H.)
| | - Jyn L Kuan
- Department of Cardiology, National University Heart Center and Cardiovascular Research Institute, National University of Singapore (J.L.K., R.Y.F.)
| | - Roger Y Foo
- Department of Cardiology, National University Heart Center and Cardiovascular Research Institute, National University of Singapore (J.L.K., R.Y.F.)
| | - Franck Potet
- From the Department of Pharmacology (L.M.W., F.P., P.W.B., A.L.G.), Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Christopher N Johnson
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University, Nashville, TN (C.N.J., W.J.C.)
| | - Miriam C Aziz
- Department of Neurology (M.C.A., G.L.C.), Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Gemma L Carvill
- Department of Neurology (M.C.A., G.L.C.), Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Juan-Pablo Kaski
- Institute of Cardiovascular Science, University College London, United Kingdom (J.-P.K.)
| | - Lia Crotti
- Department of Medicine and Surgery, University of Milano-Bicocca (L.C.).,IRCCS Istituto Auxologico Italiano, Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Milan, Italy (L.C., P.J.S.).,Cardiology Department, Health in Code SL, A Coruña, Spain (L.M.)
| | - Francesca Perin
- Pediatric Cardiology Division (F.P.), Virgen de las Nieves Hospital, Granada, Spain
| | | | - Paul W Burridge
- From the Department of Pharmacology (L.M.W., F.P., P.W.B., A.L.G.), Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Peter J Schwartz
- IRCCS Istituto Auxologico Italiano, Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Milan, Italy (L.C., P.J.S.)
| | - Walter J Chazin
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University, Nashville, TN (C.N.J., W.J.C.)
| | - Zahurul A Bhuiyan
- Unité de Recherche Cardiogénétique, Service de Médecine Génétique, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland (Z.A.B.)
| | - Alfred L George
- From the Department of Pharmacology (L.M.W., F.P., P.W.B., A.L.G.), Northwestern University Feinberg School of Medicine, Chicago, IL
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13
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Johnson CN, Pattanayek R, Potet F, Rebbeck RT, Blackwell DJ, Nikolaienko R, Sequeira V, Le Meur R, Radwański PB, Davis JP, Zima AV, Cornea RL, Damo SM, Györke S, George AL, Knollmann BC. The CaMKII inhibitor KN93-calmodulin interaction and implications for calmodulin tuning of Na V1.5 and RyR2 function. Cell Calcium 2019; 82:102063. [PMID: 31401388 DOI: 10.1016/j.ceca.2019.102063] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [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: 04/27/2019] [Revised: 07/15/2019] [Accepted: 07/26/2019] [Indexed: 02/06/2023]
Abstract
Here we report the structure of the widely utilized calmodulin (CaM)-dependent protein kinase II (CaMKII) inhibitor KN93 bound to the Ca2+-sensing protein CaM. KN93 is widely believed to inhibit CaMKII by binding to the kinase. The CaM-KN93 interaction is significant as it can interfere with the interaction between CaM and it's physiological targets, thereby raising the possibility of ascribing modified protein function to CaMKII phosphorylation while concealing a CaM-protein interaction. NMR spectroscopy, stopped-flow kinetic measurements, and x-ray crystallography were used to characterize the structure and biophysical properties of the CaM-KN93 interaction. We then investigated the functional properties of the cardiac Na+ channel (NaV1.5) and ryanodine receptor (RyR2). We find that KN93 disrupts a high affinity CaM-NaV1.5 interaction and alters channel function independent of CaMKII. Moreover, KN93 increases RyR2 Ca2+ release in cardiomyocytes independent of CaMKII. Therefore, when interpreting KN93 data, targets other than CaMKII need to be considered.
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Affiliation(s)
- Christopher N Johnson
- Center for Arrhythmia Research and Therapeutics, Vanderbilt University Medical Center, Nashville, TN 37240, USA; Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
| | - Rekha Pattanayek
- Department of Life and Physical Sciences, Fisk University, Nashville, TN 37208, USA
| | - Franck Potet
- Department of Pharmacology Feinberg School of Medicine, Northwestern University, Chicago IL, 60611, USA
| | - Robyn T Rebbeck
- Department of Biochemistry, Molecular Biology and Biophysics University of Minnesota, Minneapolis, MN 55455, USA
| | - Daniel J Blackwell
- Center for Arrhythmia Research and Therapeutics, Vanderbilt University Medical Center, Nashville, TN 37240, USA
| | - Roman Nikolaienko
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University, Maywood IL, 60153, USA
| | - Vasco Sequeira
- Department of Translational Science Universitätsklinikum, Würzburg, Germany
| | - Remy Le Meur
- Department of Biochemistry, Vanderbilt University, Nashville TN 37204, USA
| | - Przemysław B Radwański
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Jonathan P Davis
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Aleksey V Zima
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University, Maywood IL, 60153, USA
| | - Razvan L Cornea
- Department of Biochemistry, Molecular Biology and Biophysics University of Minnesota, Minneapolis, MN 55455, USA
| | - Steven M Damo
- Department of Life and Physical Sciences, Fisk University, Nashville, TN 37208, USA
| | - Sandor Györke
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Alfred L George
- Department of Pharmacology Feinberg School of Medicine, Northwestern University, Chicago IL, 60611, USA
| | - Björn C Knollmann
- Center for Arrhythmia Research and Therapeutics, Vanderbilt University Medical Center, Nashville, TN 37240, USA
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14
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Johnson CN, Potet F, Thompson MK, Kroncke BM, Glazer AM, Voehler MW, Knollmann BC, George AL, Chazin WJ. A Mechanism of Calmodulin Modulation of the Human Cardiac Sodium Channel. Structure 2018; 26:683-694.e3. [PMID: 29606593 DOI: 10.1016/j.str.2018.03.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [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: 11/03/2017] [Revised: 01/26/2018] [Accepted: 03/08/2018] [Indexed: 12/26/2022]
Abstract
The function of the human cardiac sodium channel (NaV1.5) is modulated by the Ca2+ sensor calmodulin (CaM), but the underlying mechanism(s) are controversial and poorly defined. CaM has been reported to bind in a Ca2+-dependent manner to two sites in the intracellular loop that is critical for inactivation of NaV1.5 (inactivation gate [IG]). The affinity of CaM for the complete IG was significantly stronger than that of fragments that lacked both complete binding sites. Structural analysis by nuclear magnetic resonance, crystallographic, and scattering approaches revealed that CaM simultaneously engages both IG sites using an extended configuration. Patch-clamp recordings for wild-type and mutant channels with an impaired CaM-IG interaction revealed CaM binding to the IG promotes recovery from inactivation while impeding the kinetics of inactivation. Models of full-length NaV1.5 suggest that CaM binding to the IG directly modulates channel function by destabilizing the inactivated state, which would promote resetting of the IG after channels close.
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Affiliation(s)
- Christopher N Johnson
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN 37240, USA; Department of Biochemistry, Vanderbilt University, Nashville, TN 37205, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA; Center for Arrhythmia Research and Therapeutics, Vanderbilt University, Nashville, TN 37240, USA.
| | - Franck Potet
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago IL 60611, USA
| | - Matthew K Thompson
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37205, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Brett M Kroncke
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN 37240, USA; Center for Arrhythmia Research and Therapeutics, Vanderbilt University, Nashville, TN 37240, USA
| | - Andrew M Glazer
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN 37240, USA; Center for Arrhythmia Research and Therapeutics, Vanderbilt University, Nashville, TN 37240, USA
| | - Markus W Voehler
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Bjorn C Knollmann
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN 37240, USA; Center for Arrhythmia Research and Therapeutics, Vanderbilt University, Nashville, TN 37240, USA
| | - Alfred L George
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago IL 60611, USA
| | - Walter J Chazin
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37205, USA; Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA.
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15
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Potet F, Vanoye CG, George AL. Use-Dependent Block of Human Cardiac Sodium Channels by GS967. Mol Pharmacol 2016; 90:52-60. [PMID: 27136942 DOI: 10.1124/mol.116.103358] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 04/29/2016] [Indexed: 01/22/2023] Open
Abstract
GS-458967, 6-(4-(Trifluoromethoxy)phenyl)-3-(trifluoromethyl)-[1,2,4]triazolo[4,3-a]pyridine (GS967) is a recently described, novel, sodium channel inhibitor exhibiting potent antiarrhythmic effects in various in vitro and in vivo models. The antiarrhythmic mechanism has been attributed to preferential suppression of late sodium current. However, there has been no reported systematic investigation of the effects of this compound on isolated sodium channels. Here, we examined the effects of GS967 on peak (INaP) and late (INaL) sodium current recorded from cells that heterologously expressed human cardiac voltage-gated sodium channel, the principle cardiac sodium channel. As previously described, we observed that GS967 exerted tonic block of INaL (63%) to a significantly greater extent than INaP (19%). However, GS967 also caused a reduction of INaP in a frequency-dependent manner, consistent with use-dependent block (UDB). GS967 evoked more potent UDB of INaP (IC50 = 0.07 µM) than ranolazine (16 µM) and lidocaine (17 µM). Use-dependent block was best explained by a significant slowing of recovery from fast and slow inactivation with a significant enhancement of slow inactivation in the presence of GS967. Furthermore, GS967 was found to exert these same effects on a prototypical long QT syndrome mutation (delKPQ). An engineered mutation at an interaction site for local anesthetic agents (F1760A) partially attenuated the effect of GS967 on UDB, but had no effect on tonic INaL block. We conclude that GS967 is a preferential inhibitor of INaL, but it also exerts previously unreported strong effects on slow inactivation and recovery from inactivation, resulting in substantial UDB that is not entirely dependent on a known interaction site for local anesthetic agents.
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Affiliation(s)
- Franck Potet
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - Carlos G Vanoye
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - Alfred L George
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois
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16
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Potet F, George AL. Use-Dependent Block of Human Cardiac Sodium Channels by GS967. Biophys J 2016. [DOI: 10.1016/j.bpj.2015.11.2402] [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: 11/24/2022] Open
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Potet F, Beckermann TM, Kunic JD, George AL. Intracellular calcium attenuates late current conducted by mutant human cardiac sodium channels. Circ Arrhythm Electrophysiol 2015; 8:933-41. [PMID: 26022185 DOI: 10.1161/circep.115.002760] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [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: 01/09/2014] [Accepted: 05/07/2015] [Indexed: 12/30/2022]
Abstract
BACKGROUND Mutations of the cardiac voltage-gated sodium channel (SCN5A gene encoding voltage-gated sodium channel [NaV1.5]) cause congenital long-QT syndrome type 3 (LQT3). Most NaV1.5 mutations associated with LQT3 promote a mode of sodium channel gating in which some channels fail to inactivate, contributing to increased late sodium current (INaL), which is directly responsible for delayed repolarization and prolongation of the QT interval. LQT3 patients have highest risk of arrhythmia during sleep or during periods of slow heart rate. During exercise (high heart rate), there is elevated steady-state intracellular free calcium (Ca(2+)) concentration. We hypothesized that higher levels of intracellular Ca(2+) may lower arrhythmia risk in LQT3 subjects through effects on INaL. METHODS AND RESULTS We tested this idea by examining the effects of varying intracellular Ca(2+) concentrations on the level of INaL in cells expressing a typical LQT3 mutation, delKPQ, and another SCN5A mutation, R225P. We found that elevated intracellular Ca(2+) concentration significantly reduced INaL conducted by mutant channels but not wild-type channels. This attenuation of INaL in delKPQ expressing cells by Ca(2+) was not affected by the CaM kinase II inhibitor KN-93 but was partially attenuated by truncating the C-terminus of the channel. CONCLUSIONS We conclude that intracellular Ca(2+) contributes to the regulation of INaL conducted by NaV1.5 mutants and propose that, during excitation-contraction coupling, elevated intracellular Ca(2+) suppresses mutant channel INaL and protects cells from delayed repolarization. These findings offer a plausible explanation for the lower arrhythmia risk in LQT3 subjects during fast heart rates.
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Affiliation(s)
- Franck Potet
- From the Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (F.P., A.L.G.); and Department of Medicine (F.P., J.D.K., A.L.G.) and Department of Pharmacology (T.M.B., A.L.G.), Vanderbilt University, Nashville, TN.
| | - Thomas M Beckermann
- From the Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (F.P., A.L.G.); and Department of Medicine (F.P., J.D.K., A.L.G.) and Department of Pharmacology (T.M.B., A.L.G.), Vanderbilt University, Nashville, TN
| | - Jennifer D Kunic
- From the Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (F.P., A.L.G.); and Department of Medicine (F.P., J.D.K., A.L.G.) and Department of Pharmacology (T.M.B., A.L.G.), Vanderbilt University, Nashville, TN
| | - Alfred L George
- From the Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (F.P., A.L.G.); and Department of Medicine (F.P., J.D.K., A.L.G.) and Department of Pharmacology (T.M.B., A.L.G.), Vanderbilt University, Nashville, TN
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Tanwar V, Bylund JB, Hu J, Yan J, Walthall JM, Mukherjee A, Heaton WH, Wang WD, Potet F, Rai M, Kupershmidt S, Knapik EW, Hatzopoulos AK. Gremlin 2 promotes differentiation of embryonic stem cells to atrial fate by activation of the JNK signaling pathway. Stem Cells 2015; 32:1774-88. [PMID: 24648383 DOI: 10.1002/stem.1703] [Citation(s) in RCA: 40] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 02/17/2014] [Accepted: 02/23/2014] [Indexed: 01/23/2023]
Abstract
The bone morphogenetic protein antagonist Gremlin 2 (Grem2) is required for atrial differentiation and establishment of cardiac rhythm during embryonic development. A human Grem2 variant has been associated with familial atrial fibrillation, suggesting that abnormal Grem2 activity causes arrhythmias. However, it is not known how Grem2 integrates into signaling pathways to direct atrial cardiomyocyte differentiation. Here, we demonstrate that Grem2 expression is induced concurrently with the emergence of cardiovascular progenitor cells during differentiation of mouse embryonic stem cells (ESCs). Grem2 exposure enhances the cardiogenic potential of ESCs by 20-120-fold, preferentially inducing genes expressed in atrial myocytes such as Myl7, Nppa, and Sarcolipin. We show that Grem2 acts upstream to upregulate proatrial transcription factors CoupTFII and Hey1 and downregulate atrial fate repressors Irx4 and Hey2. The molecular phenotype of Grem2-induced atrial cardiomyocytes was further supported by induction of ion channels encoded by Kcnj3, Kcnj5, and Cacna1d genes and establishment of atrial-like action potentials shown by electrophysiological recordings. We show that promotion of atrial-like cardiomyocytes is specific to the Gremlin subfamily of BMP antagonists. Grem2 proatrial differentiation activity is conveyed by noncanonical BMP signaling through phosphorylation of JNK and can be reversed by specific JNK inhibitors, but not by dorsomorphin, an inhibitor of canonical BMP signaling. Taken together, our data provide novel mechanistic insights into atrial cardiomyocyte differentiation from pluripotent stem cells and will assist the development of future approaches to study and treat arrhythmias.
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Affiliation(s)
- Vineeta Tanwar
- Department of Medicine, Division of Cardiovascular Medicine, Nashville, Tennessee, USA
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Potet F, Stepanovic S, Kupershmidt S, George AL. Nav1.5 C-Terminal Domains Influence Calcium Regulation of Fast Inactivation Separately from Calmodulin Interaction. Biophys J 2015. [DOI: 10.1016/j.bpj.2014.11.3150] [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: 10/24/2022] Open
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20
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Beckermann TM, McLeod K, Murday V, Potet F, George AL. Novel SCN5A mutation in amiodarone-responsive multifocal ventricular ectopy-associated cardiomyopathy. Heart Rhythm 2014; 11:1446-53. [PMID: 24815523 DOI: 10.1016/j.hrthm.2014.04.042] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [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: 12/31/2013] [Indexed: 12/19/2022]
Abstract
BACKGROUND Mutations in SCN5A, which encodes the cardiac sodium channel NaV1.5, typically cause ventricular arrhythmia or conduction slowing. Recently, SCN5A mutations have been associated with heart failure combined with variable atrial and ventricular arrhythmia. OBJECTIVE The purpose of this study was to determine the clinical, genetic, and functional features of an amiodarone-responsive multifocal ventricular ectopy-related cardiomyopathy associated with a novel mutation in a NaV1.5 voltage sensor domain. METHODS A novel, de novo SCN5A mutation (NaV1.5-R225P) was identified in a boy with prenatal arrhythmia and impaired cardiac contractility followed by postnatal multifocal ventricular ectopy suppressible by amiodarone. We investigated the functional consequences of NaV1.5-R225P expressed heterologously in tsA201 cells. RESULTS Mutant channels exhibited significant abnormalities in both activation and inactivation leading to large, hyperpolarized window and ramp currents that predict aberrant sodium influx at potentials near the cardiomyocyte resting membrane potential. Mutant channels also exhibited significantly increased persistent (late) sodium current. This profile of channel dysfunction shares features with other SCN5A voltage sensor mutations associated with cardiomyopathy and overlapped that of congenital long QT syndrome. Amiodarone stabilized fast inactivation, suppressed persistent sodium current, and caused frequency-dependent inhibition of channel availability. CONCLUSION We determined the functional consequences and pharmacologic responses of a novel SCN5A mutation associated with an arrhythmia-associated cardiomyopathy. Comparisons with other cardiomyopathy-associated NaV1.5 voltage sensor mutations revealed a pattern of abnormal voltage dependence of activation as a shared biophysical mechanism of the syndrome.
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Affiliation(s)
| | - Karen McLeod
- Royal Hospital for Sick Children, Yorkhill, Glasgow, Scotland, United Kingdom
| | - Victoria Murday
- Royal Hospital for Sick Children, Yorkhill, Glasgow, Scotland, United Kingdom
| | - Franck Potet
- Division of Genetic Medicine, Department of Medicine, Vanderbilt University, Nashville, Tennessee
| | - Alfred L George
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee; Division of Genetic Medicine, Department of Medicine, Vanderbilt University, Nashville, Tennessee.
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Potet F, Beckermann TM, Kunic JD, George AL. Intracellular Calcium Attenuates Persistent Current Conducted by Mutant Human Cardiac Sodium Channels in Long-QT Syndrome. Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.274] [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: 10/23/2022] Open
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Potet F, Lorinc AN, Chaigne S, Hopkins CR, Venkataraman R, Stepanovic SZ, Lewis LM, Days E, Sidorov VY, Engers DW, Zou B, Afshartous D, George AL, Campbell CM, Balser JR, Li M, Baudenbacher FJ, Lindsley CW, Weaver CD, Kupershmidt S. Identification and characterization of a compound that protects cardiac tissue from human Ether-à-go-go-related gene (hERG)-related drug-induced arrhythmias. J Biol Chem 2012; 287:39613-25. [PMID: 23033485 DOI: 10.1074/jbc.m112.380162] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human Ether-à-go-go-related gene (hERG)-encoded K(+) current, I(Kr) is essential for cardiac repolarization but is also a source of cardiotoxicity because unintended hERG inhibition by diverse pharmaceuticals can cause arrhythmias and sudden cardiac death. We hypothesized that a small molecule that diminishes I(Kr) block by a known hERG antagonist would constitute a first step toward preventing hERG-related arrhythmias and facilitating drug discovery. Using a high-throughput assay, we screened a library of compounds for agents that increase the IC(70) of dofetilide, a well characterized hERG blocker. One compound, VU0405601, with the desired activity was further characterized. In isolated, Langendorff-perfused rabbit hearts, optical mapping revealed that dofetilide-induced arrhythmias were reduced after pretreatment with VU0405601. Patch clamp analysis in stable hERG-HEK cells showed effects on current amplitude, inactivation, and deactivation. VU0405601 increased the IC(50) of dofetilide from 38.7 to 76.3 nM. VU0405601 mitigates the effects of hERG blockers from the extracellular aspect primarily by reducing inactivation, whereas most clinically relevant hERG inhibitors act at an inner pore site. Structure-activity relationships surrounding VU0405601 identified a 3-pyridiyl and a naphthyridine ring system as key structural components important for preventing hERG inhibition by multiple inhibitors. These findings indicate that small molecules can be designed to reduce the sensitivity of hERG to inhibitors.
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Affiliation(s)
- Franck Potet
- Department of Anesthesiology, Vanderbilt University, Nashville, Tennessee 37232, USA
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Potet F, Lorinc A, Hopkins C, Venkataraman R, Chaigne S, Stepanovic S, Lindsley C, Baudenbacher F, Kupershmidt S. Characterization of a Compound that Reduces Sensitivity to HERG Inhibitors and Prevents hERG-Related, Drug-Induced Arrhythmias in Isolated Rabbit Hearts. Biophys J 2012. [DOI: 10.1016/j.bpj.2011.11.101] [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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Potet F, Sebastien C, Corey H, Michelle L, Darren E, Beiyan Z, Jeffrey BR, Min L, Craig L, David W, Sabina K. Identification and Biophysical Characterization of a Compound that Protects HERG from Block by a Proarrhythmic Agent. Biophys J 2011. [DOI: 10.1016/j.bpj.2010.12.2533] [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: 10/18/2022] Open
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Stepanovic SZ, Potet F, Chagot B, Chazin W, Kupershmidt S. Mapping Residues that Influence Fast Inactivation Within Ca-Sensing Domains in the Nav1.5 C-Terminus. Biophys J 2011. [DOI: 10.1016/j.bpj.2010.12.2505] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Abstract
Aims-To establish the prevalence of c-Ki-ras gene mutations in codons 12 and 13 in 28 surgically resected Barrett's adenocarcinomas and 18 associated preneoplastic lesions in Barrett's oesophagus.Methods-Mutations were detected using the polymerase chain reaction followed by restriction fragment length polymorphism analysis. Human colon carcinoma cell lines with well characterised mutations in codons 12 and 13 were used as positive controls and to test the sensitivity of the method.Results-c-Ki-ras gene mutations were not detected in any of the 28 specimens of Barrett's adenocarcinoma or in the 18 specimens of Barrett's oesophagus (nine non-dysplastic cases, three cases with low and six with high grade dysplasia).Conclusions-These results suggest that the c-Ki-ras gene is not involved in the development of cancer in Barrett's oesophagus.
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Affiliation(s)
- C Lagorce
- Unité INSERM 410, Faculté Xavier Bichat, Paris, France
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Terris B, Fléjou JF, Dubois S, Ruszniewski P, Scoazec JY, Belghiti J, Potet F, Bernades P, Mignon M, Hénin D. Increased expression of CD44v6 in endocrine pancreatic tumours but not in midgut carcinoid tumours. Mol Pathol 2010; 49:M203-8. [PMID: 16696075 PMCID: PMC408059 DOI: 10.1136/mp.49.4.m203] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Aims/background-To analyse the different isoforms of CD44 in various types of endocrine pancreatic and gut carcinoid tumours and to investigate the relation between their expression and tumour dissemination. This study was prompted by the recent observation that inappropriate splicing of the CD44 gene was correlated with tumour progression and metastasis formation in a number of human cancers.Methods-Expression of CD44 isoforms was studied in 38 endocrine pancreatic tumours and gut neuroendocrine tumours using antibodies directed against products of exons v3, v4-v5, v6, v7-v8 as well as against the standard CD44 molecule (CD44H). CD44 gene expression was also analysed by reverse transcription PCR (RT-PCR) in nine endocrine and seven carcinoid tumours.Results-All gastrinomas except one (nine of 10) and about half of the other endocrine pancreatic tumours (seven of 15) expressed CD44v6. Most (10/11) midgut carcinoid tumours were CD44v6 negative, with no detectable immunostaining. CD44v3, CD44v4-v5 and CD44v7-v8 were not expressed in any of these tumours. CD44 mRNA analysis illustrated a complex splice pattern and expression of large CD44 isoforms in CD44v6 positive endocrine tumours, whereas the standard form only was detected in midgut carcinoid tumours. No correlation between CD44 variant expression and tumour metastasis was observed.Conclusions-CD44 variants encoding exon v6 are preferentially expressed both in gastrinomas and in most pancreatic endocrine tumours. In contrast to other tumours, the expression of CD44v6 in pancreatic neuroendocrine tumours does not seem to be correlated with tumour dissemination.
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Affiliation(s)
- B Terris
- Services d'Anatomie Pathologique, Hôpital Beaujon, Clichy, France
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Stepanovic SZ, Potet F, Petersen CI, Smith JA, Meiler J, Balser JR, Kupershmidt S. The evolutionarily conserved residue A653 plays a key role in HERG channel closing. J Physiol 2009; 587:2555-66. [PMID: 19406877 DOI: 10.1113/jphysiol.2008.166694] [Citation(s) in RCA: 9] [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: 12/16/2022] Open
Abstract
Human ether-a-go-go-related gene (HERG) encodes the rapid, outwardly rectifying K(+) current I(Kr) that is critical for repolarization of the cardiac action potential. Congenital HERG mutations or unintended pharmaceutical block of I(Kr) can lead to life-threatening arrhythmias. Here, we assess the functional role of the alanine at position 653 (HERG-A653) that is highly conserved among evolutionarily divergent K(+) channels. HERG-A653 is close to the 'glycine hinge' implicated in K(+) channel opening, and is flanked by tyrosine 652 and phenylalanine 656, which contribute to the drug binding site. We substituted an array of seven (I, C, S, G, Y, V and T) amino acids at position 653 and expressed individual variants in heterologous systems to assess changes in gating and drug binding. Substitution of A653 resulted in negative shifts of the V(1/2) of activation ranging from -23.6 (A653S) to -62.5 (A653V) compared to -11.2 mV for wild-type (WT). Deactivation was also drastically altered: channels with A653I/C substitutions exhibited delayed deactivation in response to test potentials above the activation threshold, while A653S/G/Y/V/T failed to deactivate under those conditions and required hyperpolarization and prolonged holding potentials at -130 mV. While A653S/G/T/Y variants showed decreased sensitivity to the I(Kr) inhibitor dofetilide, these changes could not be correlated with defects in channel closure. Homology modelling suggests that in the closed state, A653 forms tight contacts with several residues from the neighbouring subunit in the tetramer, playing a key role in S6 helix packing at the narrowest part of the vestibule. Our study suggests that A653 plays an important functional role in the outwardly rectifying gating behaviour of HERG, supporting channel closure at membrane potentials negative to the channel activation threshold.
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Affiliation(s)
- Svetlana Z Stepanovic
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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Chagot B, Potet F, Balser JR, Chazin WJ. Solution NMR structure of the C-terminal EF-hand domain of human cardiac sodium channel NaV1.5. J Biol Chem 2009; 284:6436-45. [PMID: 19074138 PMCID: PMC2649110 DOI: 10.1074/jbc.m807747200] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Revised: 12/05/2008] [Indexed: 12/20/2022] Open
Abstract
The voltage-gated sodium channel NaV1.5 is responsible for the initial upstroke of the action potential in cardiac tissue. Levels of intracellular calcium modulate inactivation gating of NaV1.5, in part through a C-terminal EF-hand calcium binding domain. The significance of this structure is underscored by the fact that mutations within this domain are associated with specific cardiac arrhythmia syndromes. In an effort to elucidate the molecular basis for calcium regulation of channel function, we have determined the solution structure of the C-terminal EF-hand domain using multidimensional heteronuclear NMR. The structure confirms the existence of the four-helix bundle common to EF-hand domain proteins. However, the location of this domain is shifted with respect to that predicted on the basis of a consensus 12-residue EF-hand calcium binding loop in the sequence. This finding is consistent with the weak calcium affinity reported for the isolated EF-hand domain; high affinity binding is observed only in a construct with an additional 60 residues C-terminal to the EF-hand domain, including the IQ motif that is central to the calcium regulatory apparatus. The binding of an IQ motif peptide to the EF-hand domain was characterized by isothermal titration calorimetry and nuclear magnetic resonance spectroscopy. The peptide binds between helices I and IV in the EF-hand domain, similar to the binding of target peptides to other EF-hand calcium-binding proteins. These results suggest a molecular basis for the coupling of the intrinsic (EF-hand domain) and extrinsic (calmodulin) components of the calcium-sensing apparatus of NaV1.5.
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Affiliation(s)
- Benjamin Chagot
- Department of Anesthesiology, Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232-8725, USA
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Potet F, Chagot B, Anghelescu M, Viswanathan PC, Stepanovic SZ, Kupershmidt S, Chazin WJ, Balser JR. Functional Interactions between Distinct Sodium Channel Cytoplasmic Domains through the Action of Calmodulin. J Biol Chem 2009; 284:8846-54. [PMID: 19171938 DOI: 10.1074/jbc.m806871200] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Sodium channels are fundamental signaling molecules in excitable cells, and are molecular targets for local anesthetic agents and intracellular free Ca(2+) ([Ca(2+)](i)). Two regions of Na(V)1.5 have been identified previously as [Ca(2+)](i)-sensitive modulators of channel inactivation. These include a C-terminal IQ motif that binds calmodulin (CaM) in different modes depending on Ca(2+) levels, and an immediately adjacent C-terminal EF-hand domain that directly binds Ca(2+). Here we show that a mutation of the IQ domain (A1924T; Brugada Syndrome) that reduces CaM binding stabilizes Na(V)1.5 inactivation, similarly and more extensively than even reducing [Ca(2+)](i). Because the DIII-DIV linker is an essential structure in Na(V)1.5 inactivation, we evaluated this domain for a potential CaM binding interaction. We identified a novel CaM binding site within the linker, validated its interaction with CaM by NMR spectroscopy, and revealed its micromolar affinity by isothermal titration calorimetry. Mutation of three consecutive hydrophobic residues (Phe(1520)-Ile(1521)-Phe(1522)) to alanines in this CaM-binding domain recapitulated the electrophysiology phenotype observed with mutation of the C-terminal IQ domain: Na(V)1.5 inactivation was stabilized; moreover, mutations of either CaM-binding domain abolish the well described stabilization of inactivation by lidocaine. The direct physical interaction of CaM with the C-terminal IQ domain and the DIII-DIV linker, combined with the similarity in phenotypes when CaM-binding sites in either domain are mutated, suggests these cytoplasmic structures could be functionally coupled through the action of CaM. These findings have bearing upon Na(+) channel function in genetically altered channels and under pathophysiologic conditions where [Ca(2+)](i) impacts cardiac conduction.
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Affiliation(s)
- Franck Potet
- Departments of Anesthesiology, Pharmacology, Medicine, Biochemistry, and Chemistry and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232, USA.
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Potet F, Petersen CI, Boutaud O, Shuai W, Stepanovic SZ, Balser JR, Kupershmidt S. Genetic screening in C. elegans identifies rho-GTPase activating protein 6 as novel HERG regulator. J Mol Cell Cardiol 2008; 46:257-67. [PMID: 19038263 DOI: 10.1016/j.yjmcc.2008.10.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2008] [Revised: 09/17/2008] [Accepted: 10/10/2008] [Indexed: 10/21/2022]
Abstract
The human ether-a-go-go related gene (HERG) constitutes the pore forming subunit of I(Kr), a K(+) current involved in repolarization of the cardiac action potential. While mutations in HERG predispose patients to cardiac arrhythmias (Long QT syndrome; LQTS), altered function of HERG regulators are undoubtedly LQTS risk factors. We have combined RNA interference with behavioral screening in Caenorhabditis elegans to detect genes that influence function of the HERG homolog, UNC-103. One such gene encodes the worm ortholog of the rho-GTPase activating protein 6 (ARHGAP6). In addition to its GAP function, ARHGAP6 induces cytoskeletal rearrangements and activates phospholipase C (PLC). Here we show that I(Kr) recorded in cells co-expressing HERG and ARHGAP6 was decreased by 43% compared to HERG alone. Biochemical measurements of cell-surface associated HERG revealed that ARHGAP6 reduced membrane expression of HERG by 35%, which correlates well with the reduction in current. In an atrial myocyte cell line, suppression of endogenous ARHGAP6 by virally transduced shRNA led to a 53% enhancement of I(Kr). ARHGAP6 effects were maintained when we introduced a dominant negative rho-GTPase, or ARHGAP6 devoid of rhoGAP function, indicating ARHGAP6 regulation of HERG is independent of rho activation. However, ARHGAP6 lost effectiveness when PLC was inhibited. We further determined that ARHGAP6 effects are mediated by a consensus SH3 binding domain within the C-terminus of HERG, although stable ARHGAP6-HERG complexes were not observed. These data link a rhoGAP-activated PLC pathway to HERG membrane expression and implicate this family of proteins as candidate genes in disorders involving HERG.
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Affiliation(s)
- Franck Potet
- Department of Anesthesiology, Vanderbilt University, Nashville, TN 37232, USA
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Chevalier P, Bellocq C, Millat G, Piqueras E, Potet F, Schott JJ, Baró I, Lemarec H, Barhanin J, Rousson R, Rodriguez-Lafrasse C. Torsades de pointes complicating atrioventricular block: Evidence for a genetic predisposition. Heart Rhythm 2007; 4:170-4. [PMID: 17275752 DOI: 10.1016/j.hrthm.2006.10.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2006] [Accepted: 10/03/2006] [Indexed: 11/26/2022]
Abstract
BACKGROUND The prevalence of genetic risk factors has not been systematically evaluated in the setting of complete atriventricular (AV) block complicated by long QT syndrome (LQTS). OBJECTIVE This study was performed to determine to what extent acquired LQTS in the context of AV block has a genetic substrate. METHODS Among 420 recipients of pacemakers implanted over a 3-year period, we identified retrospectively 29 patients with complete AV block and a QT interval >600 ms in duration. A second study group included 22 randomly selected patients who had AV block and a QT interval <600 ms. Normal controls were 100 consecutive individuals without medical history. Genetic studies screening for HERG, KCNQ1 KCNE1, KCNE2, and SCN5A mutations were performed. RESULTS We identified four mutations on genes encoding potassium channels in five patients with AV block and acquired LQTS. These mutations were not found among patients with AV block and a QT interval <600 ms in duration or in healthy volunteers. Functional expression of three HERG mutations (R328C, R696C, and R1047L) had a dominant negative effect on wild-type I(Kr). One KCNE2 mutation (R77W) identified in a patient treated with flecainide did not alter I(Kr). CONCLUSIONS This study showed that complete AV block complicated by LQTS was associated with HERG mutations in 17% of cases. Further studies are needed to identify factors, genetic or environmental, which may be implicated in bradycardia-related abnormalities of ventricular repolarization.
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Gouas L, Bellocq C, Berthet M, Potet F, Demolombe S, Forhan A, Lescasse R, Simon F, Balkau B, Denjoy I, Hainque B, Baró I, Guicheney P. New KCNQ1 mutations leading to haploinsufficiency in a general population; Defective trafficking of a KvLQT1 mutant. Cardiovasc Res 2004; 63:60-8. [PMID: 15194462 DOI: 10.1016/j.cardiores.2004.02.011] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2003] [Revised: 02/06/2004] [Accepted: 02/18/2004] [Indexed: 10/26/2022] Open
Abstract
OBJECTIVE KCNQ1 mutations lead to the long QT syndrome (LQTS), characterized by a prolonged QT interval, syncopes and sudden death. However, some mutations are associated with non-penetrant phenotype (no symptoms, QTc normal or borderline). The objective of this study was to determine whether KCNQ1 variants are associated with borderline QTc prolongation in a general population and to evaluate the frequency of carriers. METHODS We selected 2008 unrelated and untreated healthy individuals from a non-patient population. The KCNQ1 gene was screened by denaturing high-performance liquid chromatography (dHPLC) in 50 men and 50 women presenting the longest QTc intervals (403 to 443 ms). RESULTS We identified a nonsense mutation, Y148X, and an in-frame deletion of the serine residue 276 (DeltaS276), in S2 and S5 transmembrane domains, respectively. DeltaS276 KvLQT1 channels expressed in COS-7 cells failed to conduct any K+ current in the homozygous state. Besides, a slight reduction in channel activity was observed when coexpressed with WT KvLQT1 and IsK. Confocal microscopy performed on transfected COS-7 cells revealed that DeltaS276 KvLQT1 was retained in the endoplasmic reticulum, whereas WT KvLQT1 was localized in the cell membrane. The two mutation carriers presented borderline QTc interval prolongation at slow heart rate but a 24-h ECG recording revealed a marked QTc prolongation at higher heart rate for the Y148X carrier. CONCLUSIONS In this population, two subjects with borderline QTc prolongations (438 and 443 ms) were carriers of KCNQ1 mutations leading to haploinsufficiency and are potentially at risk of developing drug-induced arrhythmia. The study provides the first demonstration of a defective cell surface localization of a KvLQT1 mutant missing one amino acid in a transmembrane domain.
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Affiliation(s)
- Laetitia Gouas
- INSERM U582, Institut de Myologie, IFR no. 14, Groupe Hospitalier Pitié-Salpêtrière, 75651 Paris Cedex 13, France
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Probst V, Kyndt F, Potet F, Trochu JN, Mialet G, Demolombe S, Schott JJ, Baró I, Escande D, Le Marec H. Haploinsufficiency in combination with aging causes SCN5A-linked hereditary Lenègre disease. J Am Coll Cardiol 2003; 41:643-52. [PMID: 12598077 DOI: 10.1016/s0735-1097(02)02864-4] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES The goal of this study was to investigate the genotype-to-phenotype relationship between SCN5A gene mutation and progressive cardiac conduction defect in order to gain insights into the pathophysiologic mechanisms of the disease. BACKGROUND Progressive cardiac conduction defect is a frequent disease commonly attributed to degeneration and fibrosis of the His bundle and its branches. In a French family, we have identified a splicing mutation in the SCN5A gene leading to hereditary progressive cardiac conduction defect. METHODS We have extended the size of the pedigree and phenotyped and genotyped all family members, and also investigated in vitro the functional consequences of the mutation. RESULTS Among 65 potentially affected members, 25 individuals were carriers of the IVS.22+2 T-->C SCN5A mutation. In relation to aging, gene carriers exhibit various types of conduction defects. P-wave, PR, and QRS duration increased progressively with age in gene carriers and in noncarriers. Whatever the age, conduction parameters were longer in gene carriers. The widening in the QRS complex with aging was more pronounced in gene carriers older than 40 years. Functional studies show that the IVS.22+2 T-->C SCN5A mutation lead to exon 22 skipping and to a complete loss of function of the affected allele, but to a normal trafficking of the mutated gene product. CONCLUSIONS Our findings demonstrate that hereditary Lenègre disease is caused by a haploinsufficiency mechanism, which in combination with aging leads to progressive alteration in conduction velocity.
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Affiliation(s)
- Vincent Probst
- Cardiology Department, Hôpital G&R Laennec, Nantes, France
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Potet F, Mabo P, Le Coq G, Probst V, Schott JJ, Airaud F, Guihard G, Daubert JC, Escande D, Le Marec H. Novel brugada SCN5A mutation leading to ST segment elevation in the inferior or the right precordial leads. J Cardiovasc Electrophysiol 2003; 14:200-3. [PMID: 12693506 DOI: 10.1046/j.1540-8167.2003.02382.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mutations in the SCN5A gene can lead to the Brugada syndrome, a genetically inherited form of idiopathic ventricular fibrillation that has a characteristic ECG phenotype usually restricted to precordial leads V1-V3. We identified a novel G752R SCN5A missense mutation leading to various degrees of the Brugada ECG phenotype in members of a French family. In the proband, the G752R mutation produced ST segment elevation and prominent J wave in leads II, III, and aVF. In four other relatives, ST segment elevation in the right precordial but not in the inferior leads was observed either spontaneously or under flecainide challenge. Recombinant G752R mutant exhibited a markedly reduced Na+ current amplitude and a voltage shift in both activation and inactivation curves. The mutant was found in all affected but not in nonaffected family members. One additional gene-carrier had an almost normal ECG (silent gene-carrier). We provide genetic demonstration that Brugada ECG anomalies related to a unique SCN5A mutation can be observed either in the inferior or the right precordial leads.
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Affiliation(s)
- Franck Potet
- Institut National de la Santé et de la Recherche Médicale (INSERM) U533, Faculté de Médecine, the Cardiology Department, Hôpital G&R Laennec, Nantes, France
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Murray A, Potet F, Bellocq C, Baró I, Reardon W, Hughes HE, Jeffery S. Mutation in KCNQ1 that has both recessive and dominant characteristics. J Med Genet 2002; 39:681-5. [PMID: 12205113 PMCID: PMC1735237 DOI: 10.1136/jmg.39.9.681] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Kyndt F, Probst V, Potet F, Demolombe S, Chevallier JC, Baro I, Moisan JP, Boisseau P, Schott JJ, Escande D, Le Marec H. Novel SCN5A mutation leading either to isolated cardiac conduction defect or Brugada syndrome in a large French family. Circulation 2001; 104:3081-6. [PMID: 11748104 DOI: 10.1161/hc5001.100834] [Citation(s) in RCA: 264] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND The SCN5A gene encoding the human cardiac sodium channel alpha subunit plays a key role in cardiac electrophysiology. Mutations in SCN5A lead to a large spectrum of phenotypes, including long-QT syndrome, Brugada syndrome, and isolated progressive cardiac conduction defect (Lenègre disease). METHODS AND RESULTS In the present study, we report the identification of a novel single SCN5A missense mutation causing either Brugada syndrome or an isolated cardiac conduction defect in the same family. A G-to-T mutation at position 4372 was identified by direct sequencing and was predicted to change a glycine for an arginine (G1406R) between the DIII-S5 and DIII-S6 domain of the sodium channel protein. Among 45 family members, 13 were carrying the G1406R SCN5A mutation. Four individuals from 2 family collateral branches showed typical Brugada phenotypes, including ST-segment elevation in the right precordial leads and right bundle branch block. One symptomatic patient with the Brugada phenotype required implantation of a cardioverter-defibrillator. Seven individuals from 3 other family collateral branches had isolated cardiac conduction defects but no Brugada phenotype. Three flecainide test were negative. One patient with an isolated cardiac conduction defect had an episode of syncope and required pacemaker implantation. An expression study of the G1406R-mutated SCN5A showed no detectable Na(+) current but normal protein trafficking. CONCLUSIONS We conclude that the same mutation in the SCN5A gene can lead either to Brugada syndrome or to an isolated cardiac conduction defect. Our findings suggest that modifier gene(s) may influence the phenotypic consequences of a SCN5A mutation.
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Affiliation(s)
- F Kyndt
- Laboratoire de Physiopathologie et de Pharmacologie Cellulaires et Moléculaires, INSERM U533, Paris, France
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Potet F, Bouyssou T, Escande D, Baró I. Gastrointestinal prokinetic drugs have different affinity for the human cardiac human ether-à-gogo K(+) channel. J Pharmacol Exp Ther 2001; 299:1007-12. [PMID: 11714889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023] Open
Abstract
Agonists of the serotonin 5-hydroxytryptamine 4 (5-HT4) receptor are widely used to activate motility in the gastrointestinal tract. Among these, cisapride was recently withdrawn from the U.S. market because of its proarrhythmic effects. Cisapride is a potent blocker of human ether-à-gogo (HERG) K(+) channels and prolongs the cardiac action potential in a reverse use dependence manner. We compared the effects of four different 5-HT4 receptor agonists (cisapride, prucalopride, renzapride and mosapride) on cloned HERG channels with the objective to evaluate and compare their proarrhythmic potential. K(+) currents from HERG-transfected COS-7 cells were recorded under physiological conditions using the whole cell configuration of the patch-clamp technique. Short (500 ms) depolarizing prepulses were used and following deactivating HERG currents were measured. Cisapride inhibited the HERG channels in a concentration-dependent manner with an IC(50) of 2.4 10(-7) M. The IC(50) value for prucalopride to block HERG (5.7 10(-6) M) was 20-fold higher than that of cisapride. Renzapride was slightly more potent than prucalopride (IC(50) = 1.8 10(-6) M). Mosapride produced no significant effects on the recombinant HERG current. The voltage dependence of HERG block was also investigated. The block mediated by cisapride or renzapride was voltage-dependent whereas that produced by prucalopride was not. We conclude that the rank order of potency of 5-HT4 agonists to block HERG is cisapride > renzapride > prucalopride > mosapride. We also conclude that 5-HT4 agonists devoid of side effects on the HERG current such as mosapride can be found as a safe alternative to cisapride.
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Affiliation(s)
- F Potet
- Institut National de la Sante et de la Recherche Medicale U533 Laboratoire de Physiopathologie et de Pharmacologie Cellulaires et Moléculaires, Hôpital Hôtel-Dieu, Nantes, France
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39
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Chevalier P, Rodriguez C, Bontemps L, Miquel M, Kirkorian G, Rousson R, Potet F, Schott JJ, Baró I, Touboul P. Non-invasive testing of acquired long QT syndrome: evidence for multiple arrhythmogenic substrates. Cardiovasc Res 2001; 50:386-98. [PMID: 11334843 DOI: 10.1016/s0008-6363(01)00263-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Although well-defined clinically and electrocardiographically, Acquired Long QT Syndrome (LQTS) remains elusive from a pathophysiologic point of view. An increasingly accepted hypothesis is that it represents an attenuated form of Congenital Long QT Syndrome. To test this hypothesis further, we investigated patients with Acquired LQTS, using various investigations that are known to give information in patients with Congenital LQTS. METHODS All the investigations were performed in patients with a history of Acquired Long QT Syndrome, defined by marked transient QT lengthening (QT>600 ms) and/or torsades de pointes. Measurement of the QT interval dispersion, the interlead difference for the QT interval on a 12-lead ECG, was performed in 18 patients and compared with 18 controls, matched for age and sex. To assess sympathetic myocardial innervation, I-123 Meta-iodobenzylguanidine (I-123-MIBG) scintigraphy was performed in 12 patients, together with Thallium scintigraphy, to rule out abnormal myocardial perfusion. Time-frequency analysis of a high-resolution ECG using a wavelet technique, was made for nine patients and compared with 38 healthy controls. Finally, genetic studies were performed prospectively in 16 consecutive patients, to look for HERG, KCNE1, KCNE2 and KCNQ1 mutations. The functional profile of a mutated HERG protein was performed using the patch-clamp technique. RESULTS Compared with the control group, a significant increase in QT dispersion was observed in the patients with a history of Acquired LQTS (55+/-15 vs. 33+/-9 ms, P<0.001). In another group of patients with Acquired LQTS, 123 I-MIBG tomoscintigraphy demonstrated a decrease in the sympathetic myocardial innervation. Time--frequency analysis using wavelet transform, demonstrated an abnormal frequency content within the QRS complexes, in the patients with Acquired LQTS, similar to that found in Congenital LQTS patients. Molecular screening in 16 consecutive patients, identified one patient with a missense mutation on HERG, one of the LQTS genes. Expression of the mutated HERG protein led to altered K(+) channel function. CONCLUSION Our results suggest that Acquired and Congenital Long QT Syndromes have some common features. They allow the mechanism of the clinical heterogeneity, found in both syndromes, to be understood. Further multi-facet approaches are needed to decipher the complex interplay between the main determinants of these arrhythmogenic diseases.
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Affiliation(s)
- P Chevalier
- Département de Cardiologie et de Soins Intensifs, Hôpital Louis Pradel, Lyon, France
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40
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Abstract
In cardiac myocytes, the slow component of the delayed rectifier K(+) current (I(Ks)) is regulated by cAMP. Elevated cAMP increases I(Ks) amplitude, slows its deactivation kinetics, and shifts its activation curve. At the molecular level, I(Ks) channels are composed of KvLQT1/IsK complexes. In a variety of mammalian heterologous expression systems maintained at physiological temperature, we explored cAMP regulation of recombinant KvLQT1/IsK complexes. In these systems, KvLQT1/IsK complexes were totally insensitive to cAMP regulation. cAMP regulation was not restored by coexpression with the dominant negative isoform of KvLQT1 or with the cystic fibrosis transmembrane regulator. In contrast, coexpression of the neuronal A kinase anchoring protein (AKAP)79, a fragment of a cardiac AKAP (mAKAP), or cardiac AKAP15/18 restored cAMP regulation of KvLQT1/IsK complexes inasmuch as cAMP stimulation increased the I(Ks) amplitude, increased its deactivation time constant, and negatively shifted its activation curve. However, in cells expressing an AKAP, the effects of cAMP stimulation on the I(Ks) amplitude remained modest compared with those previously reported in cardiac myocytes. The effects of cAMP stimulation were fully prevented by including the Ht31 peptide (a global disruptor of protein kinase A anchoring) in the intracellular medium. We concluded that cAMP regulation of I(Ks) requires protein kinase A anchoring by AKAPs, which therefore participate with the channel protein complex underlying I(Ks).
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Affiliation(s)
- F Potet
- Laboratoire de Physiopathologie et de Pharmacologie Cellulaires et Moléculaires, Hôpital Hôtel-Dieu, Institut National de la Santé et de la Recherche Médicale, 44093 Nantes Cedex, France
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41
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Charton-Bain MC, Terris B, Dauge MC, Marche C, Walker F, Bouchaud O, Xerri L, Potet F. Reduced number of Langerhans cells in oesophageal mucosa from AIDS patients. Histopathology 1999; 34:399-404. [PMID: 10231413 DOI: 10.1046/j.1365-2559.1999.00653.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS The oesophageal mucosa is a frequent target of opportunistic infections in human immunodeficiency virus (HIV) infection. Langerhans cells (LC) are known as a target and reservoir of HIV in the skin. The aim of this study was to characterize oesophageal LC in HIV-infected patients. METHODS AND RESULTS Thirty oesophageal biopsies were obtained from 29 patients (median age 35.5), all in stage IV of the HIV Center of Disease Control Classification. We performed histological assessment of the oesophageal mucosa and immunohistochemical detection of oesophageal LC using an anti-CD1a antibody, followed by morphometric analysis. Biopsies from 17 noninfected patients were studied using the same procedure. LC in oesophageal mucosa of the HIV positive patients showed a significantly and dramatically decreased number (LC(N) median = 5.85/mm2) and surface/epithelial surface (LC (S) ratio = 0.09) when compared with HIV-negative controls (LC(N) median = 29.7/mm2, LC(S) ratio = 1.83) with P = 0.003 for LC(N) and P < 0.0001 for LC(S). CONCLUSION These data suggest that oesophageal LC are, like their epidermal counterparts, a preferential target for HIV infection. Their alterations may provide a clue to the pathogenesis of the decreased local oesophageal immunity and to the occurrence of opportunistic infections.
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Affiliation(s)
- M C Charton-Bain
- Service d'Anatomie Pathologique, Groupe Hospitalier Bichat-Claude Bernard, Paris, France
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42
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Sobhani I, Brousse N, Vissuzaine C, Mcintyre E, Marmuse JP, Kahn MF, Potet F, Mignon M. A diffuse T lymphocytic gastrointestinal mucosal infiltration associated with Sjögren's syndrome resulting in a watery diarrhea syndrome and responsive to immunosuppressive therapy. Am J Gastroenterol 1998; 93:2584-6. [PMID: 9860433 DOI: 10.1111/j.1572-0241.1998.00724.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We report the case of a 45-yr-old white man, investigated for chronic diarrhea, malabsorption and weight loss associated with sicca syndrome. Endoscopic and x-ray examinations showed normal macroscopic mucosa in gastrointestinal tract (GIT). Immunohistochemistry showed diffuse polyclonal T cell lymphocytes infiltrating either epithelium and lamina propria in GIT. There was no villous atrophy in the jejunum and ileum. Corticosteroids, azathioprine, and cyclosporine failed to improve symptoms. Monthly intravenous cyclophosphamide administered over 1 yr, stopped the diarrhea and weight loss. The patient is free of symptoms up to a 5-yr follow-up.
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Affiliation(s)
- I Sobhani
- Department of Gastroenterology, Bichat Claude Bernard Hospital, Paris, France
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43
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Abstract
AIMS To describe ticlopidine related microscopic colitis and to assess the occurrence of apoptosis in the colon epithelium. METHODS A series of colorectal biopsy samples from nine patients with ticlopidine related chronic diarrhoea were analysed. Biopsies were also taken from five of these patients between two and four months after ticlopidine withdrawal. The number of apoptotic cells in the crypts/mm2 (apoptotic index) was calculated using in situ labelling by terminal deoxyribonucleotidyl transferase (TdT) mediated dUTP-biotin nick end labelling (TUNEL). All specimens were matched to normal colorectal specimens from a control group of comparable age and sex distribution. RESULTS Histological examination of the colon biopsy specimens taken from all nine patients with ticlopidine related chronic diarrhoea showed characteristic features of microscopic colitis. The histology returned to normal when ticlopidine was withdrawn. Apoptotic cells were rarely found in controls, and the mean apoptotic index was 0.53. The apoptotic index was significantly higher (16.53) in ticlopidine related colitis, but decreased dramatically to control value when ticlopidine was withdrawn. CONCLUSION Microscopic colitis can be induced by ticlopidine and is accompanied by an increase in epithelial apoptosis. Hence, increased apoptosis might be related to drug injury or might be part of microscopic colitis.
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Affiliation(s)
- D Berrebi
- Service d'Anatomie, Hôpital Bichat, Paris, France
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44
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Cuillerier E, Coffin B, Potet F, Dapoigny M, Flourie B, Coffin JC, Benyahia B, Bitoun A, Messing B, Rambaud JC. [Paraneoplastic intestinal pseudo-obstruction revealing small cell lung carcinoma: "the anti-Hu syndrome"]. Gastroenterol Clin Biol 1998; 22:346-8. [PMID: 9762221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
A 67-year-old woman was admitted for intestinal pseudoobstruction associated with peripheral sensitive neuropathy. Jejunal biopsies performed during laparotomy, showed axonal degeneration and lympho-plasmocytic infiltration in myenteric plexus. High titer of seric anti-Hu antibodies suggested a paraneoplastic syndrome. Thoracic CT scan showed mediastinal lymph nodes. Their histological examination confirmed the diagnosis of metastatic small-cell lung carcinoma. Her condition gradually deteriorated despite supportive parenteral nutrition, chemotherapy, steroids and intravenous immunoglobulins. She died 12 months after the onset of symptoms.
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Affiliation(s)
- E Cuillerier
- Service de Gastroentérologie, Hôpital Saint-Lazare, Paris
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45
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Darai E, Walker-Combrouze F, Fauconnier A, Madelenat P, Potet F, Scoazec JY. Analysis of CD44 expression in serous and mucinous borderline tumours of the ovary: comparison with cystadenomas and overt carcinomas. Histopathology 1998; 32:151-9. [PMID: 9543672 DOI: 10.1046/j.1365-2559.1998.00347.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
AIMS To determine the diagnostic and prognostic value of the immunohistochemical analysis of CD44 variants in benign borderline and malignant tumours of the ovary. METHODS AND RESULTS The reactivity of tumour cells with three monoclonal antibodies, respectively, directed to all CD44 variants, CD44-v3 isoform and CD44-v6 isoform, was assessed by using an indirect immunoperoxidase technique applied to formalin-fixed, paraffin-embedded samples of 36 cases of borderline, as compared to 20 cases of benign tumours and 20 cases of carcinomas. CD44 variants were detected in 97% of borderline tumours, as compared to 60% of benign tumours and 100% of carcinomas. CD44-v3 was detected in 25% of borderline tumours, as compared to 0% of benign tumours (P = 0.003) and 55% of carcinomas (P = 0.065). The expression of CD44-v6 was detected in 28% of borderline tumours, as compared to 20% of benign tumours and 30% of carcinomas. In borderline tumours, as in carcinomas, CD44-v6, but not CD44-v3, expression was correlated with an increased proliferative index and with a higher incidence of p53 expression. CONCLUSION Borderline tumours of the ovary present frequent quantitative and qualitative alterations in the pattern of expression of CD44 proteins. However, these alterations are unlikely to represent useful diagnostic or prognostic markers.
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Affiliation(s)
- E Darai
- Service de Gynécologie-Obstétrique, Hôpital Bichat-Claude Bernard, Paris, France
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46
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Berrebi D, Banerjee A, Paris R, Potet F, Aigrain Y, Emilie D, Cezard JP, Hugot JP, Navarro J, Peuchmaur M. In situ Rantes and interferon-gamma gene expression in pediatric small bowel Crohn's disease. J Pediatr Gastroenterol Nutr 1997; 25:371-6. [PMID: 9327364 DOI: 10.1097/00005176-199710000-00001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Rantes (regulated upon activation, normal T cell expressed and secreted) is a chemotactic cytokine for memory T lymphocytes, monocytes, and eosinophils. The cytokine interferon-gamma (IFN-gamma) plays a key in the immune response. Their distributions and possible roles in the selective accumulation of inflammatory cells in Crohn's disease (CD) were examined by determining the expression of Rantes and IFN-gamma genes in patients with CD using in situ hybridization (ISH) on frozen and paraffin-embedded tissue sections. METHODS Intestinal and mesenteric lymph node samples from 9 children who had undergone ileal resection for CD were examined for the presence of epithelioid-giant cell granulomas (EGCG) and Rantes and IFN-gamma messenger RNA (mRNA). Normal pediatric intestine (n = 5) and lymph nodes (n = 2) served as controls. RESULTS Many cells in all CD specimens in the epithelial compartment, lamina propria, and the EGCG gave positive signal with the Rantes antisense probe. Labelled cells were identified on paraffin sections as lymphocytes, macrophages, and epithelioid cells. There were Rantes-positive cells in the control intestinal tissues, but many Rantes-positive cells in control lymph nodes that showed follicular hyperplasia. IFN-gamma-positive cells were present in all CD ileal and lymph node specimens, predominantly in close contact with EGCC. No positive signal was obtained with the Rantes and IFN-gamma sense control probes. CONCLUSIONS These findings suggest that Rantes and IFN-gamma contribute to the selective accumulation of macrophages and memory T helper lymphocytes inside the granulomas and inflammatory infiltrates that are characteristic of CD.
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Affiliation(s)
- D Berrebi
- Service d'Anatomie, Hôpital Robert Debré, Paris, France
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47
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Daraï E, Scoazec JY, Walker-Combrouze F, Mlika-Cabanne N, Feldmann G, Madelenat P, Potet F. Expression of cadherins in benign, borderline, and malignant ovarian epithelial tumors: a clinicopathologic study of 60 cases. Hum Pathol 1997; 28:922-8. [PMID: 9269828 DOI: 10.1016/s0046-8177(97)90007-1] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We have analyzed the expression of E- and N-cadherins in benign, borderline, and maligant ovarian tumors, and we have correlated the pattern of cadherin expression with the standard clinicopathological parameters. An immunohistochemical technique has been applied to formalin-fixed, paraffin-embedded samples of 20 benign cystic tumors, 20 borderline tumors, and 20 cancers. Expression of E- and N-cadherins immunostaining were compared with the histological type, degree of histological differentiation, International Federation of Gynecology and Obstetrics (FIGO) stage, presence of ascites, occurrence of recurrence, and survival. E-cadherin was homogeneosuly expressed in benign tumors but was heterogeneously expressed or undetectable in most borderline and malignant tumors. In contrast, N-cadherin was detected in most benign and borderline tumors but was absent or heterogeneous in most carcinomas. The difference of expression of E-cadherin and N-cadherin between the three groups of ovarian tumors was statistically significant (respectively, P = .03 and P < .001). In ovarian carcinoma, patients with negative E-cadherin staining present a significantly shorter survival. No correlation was found between cadherin expression and clinicopathological parameters in borderline tumors. Our results suggest that alterations in E-cadherin and N-cadherin expressions are differentially involved in ovarian carcinogenesis and may have diagnostic and prognostic values.
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Affiliation(s)
- E Daraï
- Service de Gynécologie, Hôpital Bichat-Claude-Bernard, Paris, France
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48
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Couvelard A, Schweizer-Lapeyre L, Carle JP, Marsault S, Le Blaye O, Marche C, Potet F. [Hyperplastic polyps arising in islands of gastric mucosa in the duodenum]. Ann Pathol 1997; 17:203-5. [PMID: 9296581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Hyperplastic polyps originating from islands of gastric mucosa can be observed in the duodenum. We report 3 cases of duodenal hyperplastic polyps on antral or fully developed fundic mucosa. They macroscopically presented as small confluent polyps or as large villous polyps. Their microscopic features were the same as those observed in hyperplastic gastric polyps. This type of polyp must be added to the list of tumor like lesions of the duodenum that may endoscopically present as polyps.
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Affiliation(s)
- A Couvelard
- Service d'Anatomie Pathologique, Hôpital Bichat-Claude Bernard, Paris
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49
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Darai E, Majidi-Ahi A, Walker-Combrouze F, Benifla JL, Madelenat P, Potet F. Unique uterine metastasis restricted to a leiomyoma. EUR J GYNAECOL ONCOL 1997; 18:111-2. [PMID: 9105858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- E Darai
- Department of Gynecology and Obstetrics, University Hospital Bichat, Paris, France
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50
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Cymes K, Potet F, Dauge-Geffroy MC, Fléjou JF, Rampal A, Klein O, Rampal P, Goldfain D, Rotenberg A. [Are lymphocytic and collagenous colitis two forms of a single disease? Arguments taken from a biopsy quantitative study]. Ann Pathol 1996; 16:430-4. [PMID: 9090931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Collagenous colitis and lymphocytic colitis are defined by a clinicopathologic syndrome with chronic watery diarrhea, microscopic lesions of colonic biopsies, and normal barium enema and colonoscopy. A histopathological study was performed on multiple colorectal biopsies to compare 12 cases of collagenous colitis (defined by a subepithelial collagen thicker than 10 microns) and 7 cases of lymphocytic colitis (defined by a number of intraepithelial lymphocytes more than 20 per 100 epithelial cells at least in one biopsied site). The study included a semiquantitative analysis of inflammatory infiltrate in the lamina propria, crypts distortion and epithelial detachment. The number of intraepithelial lymphocytes per 100 epithelial cells was determined in surface epithelium and crypts. The subepithelial collagen thickening was studied by computerised morphometry. The intraepithelial lymphocytes, villous atrophy and thickness of the subepithelial collagen were also determined in gastric and duodenal biopsies. In collagenous colitis, the subepithelial collagenous thickness ranged from 10 to 40 microns in the colon (median 20.99 microns). In 4 cases of collagenous colitis, no thickening of the collagen plate was seen in the rectum. We found constant epithelial detachment and mucosal distortion. In lymphocytic colitis, the thickness of the subepithelial collagen ranged from 6 to 10 microns in 4 cases and was less than 6 microns in 3 cases (median 6.24 microns). The median number of intraepithelial lymphocytes in surface epithelium was 22.35 (range 18.2 to 40) in lymphocytic colitis versus 12.22 (range 4.6 to 24.4) in collagenous colitis. In conclusion, we observed an overlap of both the collagenous plate thickness and the number of intraepithelial lymphocytes in collagenous colitis and lymphocytic colitis. This result favours a unified histogenesis for these two entities.
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Affiliation(s)
- K Cymes
- Services d'Anatomie Pathologique, Hôpital Bichat, Clichy
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