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Zaytseva AK, Kulichik OE, Kostareva AA, Zhorov BS. Biophysical mechanisms of myocardium sodium channelopathies. Pflugers Arch 2024; 476:735-753. [PMID: 38424322 DOI: 10.1007/s00424-024-02930-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 02/15/2024] [Accepted: 02/16/2024] [Indexed: 03/02/2024]
Abstract
Genetic variants of gene SCN5A encoding the alpha-subunit of cardiac voltage-gated sodium channel Nav1.5 are associated with various diseases, including long QT syndrome (LQT3), Brugada syndrome (BrS1), and progressive cardiac conduction disease (PCCD). In the last decades, the great progress in understanding molecular and biophysical mechanisms of these diseases has been achieved. The LQT3 syndrome is associated with gain-of-function of sodium channels Nav1.5 due to impaired inactivation, enhanced activation, accelerated recovery from inactivation or the late current appearance. In contrast, BrS1 and PCCD are associated with the Nav1.5 loss-of-function, which in electrophysiological experiments can be manifested as reduced current density, enhanced fast or slow inactivation, impaired activation, or decelerated recovery from inactivation. Genetic variants associated with congenital arrhythmias can also disturb interactions of the Nav1.5 channel with different proteins or drugs and cause unexpected reactions to drug administration. Furthermore, mutations can affect post-translational modifications of the channels and their sensitivity to pH and temperature. Here we briefly review the current knowledge on biophysical mechanisms of LQT3, BrS1 and PCCD. We focus on limitations of studies that use heterologous expression systems and induced pluripotent stem cells (iPSC) derived cardiac myocytes and summarize our understanding of genotype-phenotype relations of SCN5A mutations.
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Affiliation(s)
- Anastasia K Zaytseva
- Almazov National Medical Research Centre, St. Petersburg, Russia.
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia.
| | - Olga E Kulichik
- Almazov National Medical Research Centre, St. Petersburg, Russia
| | | | - Boris S Zhorov
- Almazov National Medical Research Centre, St. Petersburg, Russia
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
- McMaster University, Hamilton, Canada
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Liang J, Luo S, Huang B. Case Report: SCN5A mutations in three young patients with sick sinus syndrome. Front Cardiovasc Med 2023; 10:1294197. [PMID: 38107266 PMCID: PMC10722160 DOI: 10.3389/fcvm.2023.1294197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 11/17/2023] [Indexed: 12/19/2023] Open
Abstract
Background Sick Sinus Syndrome (SSS) is generally regarded as a degenerative disease with aging; however, genetic mutations have been confirmed to be associated with SSS. Among them, mutations in SCN5A are common in patients with SSS. We report three young SSS patients with SCN5A mutations at different sites that have not been previously reported in Asian patients. Case presentation The three patients were all young females who presented with symptoms of severe bradycardia and paroxysmal atrial flutter, for which two patients received ablation therapy. However, after ablation, Holter monitoring indicated a significant long cardiac arrest; therefore, the patients received pacemaker implantation. The three patients had familial SSS, and genetic testing was performed. Mutations were found in SCN5A at different sites in the three families. All three patients received pacemaker implantation, resulting in the symptoms of severe bradycardia disappearing. Conclusion SCN5A heterozygous mutations are common among patients clinically affected by SSS. Their causative role is confirmed by our data and by the co-occurrence of genetic arrhythmias among our patients. Genetic testing for SSS cannot be performed as a single gene panel because of feasible literature results, but in presence of familial and personal history of SSS in association with arrhythmias can provide clinically useful information.
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Affiliation(s)
| | - Suxin Luo
- Department of Cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Bi Huang
- Department of Cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
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Hu X, Kong J, Niu T, Chen L, Yang J. Single coronary artery presenting dilated cardiomyopathy and hyperlipidemia with the SCN5A and APOA5 gene mutation: A case report and review of the literature. Front Cardiovasc Med 2023; 10:1113886. [PMID: 37288251 PMCID: PMC10242075 DOI: 10.3389/fcvm.2023.1113886] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 03/23/2023] [Indexed: 06/09/2023] Open
Abstract
We present a 55-year-old man with chest tightness and dyspnoea after activity lasting for 2 months who was diagnosed with single coronary artery (SCA) and presented with dilated cardiomyopathy (DCM) with the c.1858C > T mutation in the SCN5A gene. The computed tomography coronary angiogram (CTCA) showed congenital absence of the right coronary artery (RCA), and the right heart was nourished by the left coronary artery branch with no apparent stenosis. Transthoracic echocardiography (TTE) revealed enlargement of the left heart and cardiomyopathy. Cardiac magnetic resonance imaging (CMR) revealed DCM. Genetic testing showed that the c.1858C > T variant of the SCN5A gene could lead to Brugada syndrome and DCM. SCA is a rare congenital anomaly of the coronary anatomy, and this case reported as SCA accompanied by DCM is even rarer. We present a rare case of a 55-year-old man with DCM with the c.1858C > T (p. Arg620Cys)/c.1008G > A (p.(Pro336=) variant of the SCN5A gene, congenital absence of RCA, and c.990_993delAACA (p. Asp332Valfs*5) variant of the APOA5 gene. To our knowledge, this is the first report of DCM combined with the SCN5A gene mutation in SCA after searching the PubMed, CNKI and Wanfang databases.
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Affiliation(s)
- Xiaoxia Hu
- Department of Cardiology, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Jing Kong
- Department of Cardiology, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Tingting Niu
- Department of Medical Technology, Jinan Vocational College of Nursing, Jinan, Shandong, China
| | - Liang Chen
- Department of Emergency Medicine, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Jingjing Yang
- Department of Emergency Medicine, Qilu Hospital of Shandong University, Jinan, Shandong, China
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Bersell KR, Yang T, Mosley JD, Glazer AM, Hale AT, Kryshtal DO, Kim K, Steimle JD, Brown JD, Salem JE, Campbell CC, Hong CC, Wells QS, Johnson AN, Short L, Blair MA, Behr ER, Petropoulou E, Jamshidi Y, Benson MD, Keyes MJ, Ngo D, Vasan RS, Yang Q, Gerszten RE, Shaffer C, Parikh S, Sheng Q, Kannankeril PJ, Moskowitz IP, York JD, Wang TJ, Knollmann BC, Roden DM. Transcriptional Dysregulation Underlies Both Monogenic Arrhythmia Syndrome and Common Modifiers of Cardiac Repolarization. Circulation 2023; 147:824-840. [PMID: 36524479 PMCID: PMC9992308 DOI: 10.1161/circulationaha.122.062193] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 11/03/2022] [Indexed: 12/23/2022]
Abstract
BACKGROUND Brugada syndrome (BrS) is an inherited arrhythmia syndrome caused by loss-of-function variants in the cardiac sodium channel gene SCN5A (sodium voltage-gated channel alpha subunit 5) in ≈20% of subjects. We identified a family with 4 individuals diagnosed with BrS harboring the rare G145R missense variant in the cardiac transcription factor TBX5 (T-box transcription factor 5) and no SCN5A variant. METHODS We generated induced pluripotent stem cells (iPSCs) from 2 members of a family carrying TBX5-G145R and diagnosed with Brugada syndrome. After differentiation to iPSC-derived cardiomyocytes (iPSC-CMs), electrophysiologic characteristics were assessed by voltage- and current-clamp experiments (n=9 to 21 cells per group) and transcriptional differences by RNA sequencing (n=3 samples per group), and compared with iPSC-CMs in which G145R was corrected by CRISPR/Cas9 approaches. The role of platelet-derived growth factor (PDGF)/phosphoinositide 3-kinase (PI3K) pathway was elucidated by small molecule perturbation. The rate-corrected QT (QTc) interval association with serum PDGF was tested in the Framingham Heart Study cohort (n=1893 individuals). RESULTS TBX5-G145R reduced transcriptional activity and caused multiple electrophysiologic abnormalities, including decreased peak and enhanced "late" cardiac sodium current (INa), which were entirely corrected by editing G145R to wild-type. Transcriptional profiling and functional assays in genome-unedited and -edited iPSC-CMs showed direct SCN5A down-regulation caused decreased peak INa, and that reduced PDGF receptor (PDGFRA [platelet-derived growth factor receptor α]) expression and blunted signal transduction to PI3K was implicated in enhanced late INa. Tbx5 regulation of the PDGF axis increased arrhythmia risk due to disruption of PDGF signaling and was conserved in murine model systems. PDGF receptor blockade markedly prolonged normal iPSC-CM action potentials and plasma levels of PDGF in the Framingham Heart Study were inversely correlated with the QTc interval (P<0.001). CONCLUSIONS These results not only establish decreased SCN5A transcription by the TBX5 variant as a cause of BrS, but also reveal a new general transcriptional mechanism of arrhythmogenesis of enhanced late sodium current caused by reduced PDGF receptor-mediated PI3K signaling.
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Affiliation(s)
- Kevin R Bersell
- Departments of Pharmacology (K.R.B., A.M.G., D.O.K., K.K., J-E.S., C.C.C., Q.S.W., S.P., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | - Tao Yang
- Medicine (T.Y., J.D.M., J.D.B., J-E.S., Q.S.W., L.S., M.A.B., C.S., T.J.W., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | - Jonathan D Mosley
- Departments of Pharmacology (K.R.B., A.M.G., D.O.K., K.K., J-E.S., C.C.C., Q.S.W., S.P., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | - Andrew M Glazer
- Departments of Pharmacology (K.R.B., A.M.G., D.O.K., K.K., J-E.S., C.C.C., Q.S.W., S.P., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | - Andrew T Hale
- Biochemistry (A.T.H., J.D.Y.), Vanderbilt University, Nashville, TN
| | - Dmytro O Kryshtal
- Departments of Pharmacology (K.R.B., A.M.G., D.O.K., K.K., J-E.S., C.C.C., Q.S.W., S.P., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | - Kyungsoo Kim
- Departments of Pharmacology (K.R.B., A.M.G., D.O.K., K.K., J-E.S., C.C.C., Q.S.W., S.P., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | - Jeffrey D Steimle
- Departments of Pediatrics, Pathology, and Human Genetics, University of Chicago, IL (J.D.S., I.P.M.)
| | - Jonathan D Brown
- Medicine (T.Y., J.D.M., J.D.B., J-E.S., Q.S.W., L.S., M.A.B., C.S., T.J.W., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | - Joe-Elie Salem
- Departments of Pharmacology (K.R.B., A.M.G., D.O.K., K.K., J-E.S., C.C.C., Q.S.W., S.P., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
- Medicine (T.Y., J.D.M., J.D.B., J-E.S., Q.S.W., L.S., M.A.B., C.S., T.J.W., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
- Assistance Publique - Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Department of Pharmacology, CIC-1901, Sorbonne University, Paris, France (J-E.S.)
- Sorbonne Universités, UPMC Univ Paris 06, Faculty of Medicine, France (J-E.S.)
| | - Courtney C Campbell
- Departments of Pharmacology (K.R.B., A.M.G., D.O.K., K.K., J-E.S., C.C.C., Q.S.W., S.P., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | - Charles C Hong
- Department of Medicine, University of Maryland School of Medicine, Baltimore (C.C.H.)
| | - Quinn S Wells
- Departments of Pharmacology (K.R.B., A.M.G., D.O.K., K.K., J-E.S., C.C.C., Q.S.W., S.P., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
- Medicine (T.Y., J.D.M., J.D.B., J-E.S., Q.S.W., L.S., M.A.B., C.S., T.J.W., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
- Biomedical Informatics (Q.S.W., D.M.R.), Vanderbilt University, Nashville, TN
| | - Amanda N Johnson
- Molecular Physiology and Biophysics (A.N.J.), Vanderbilt University, Nashville, TN
| | - Laura Short
- Medicine (T.Y., J.D.M., J.D.B., J-E.S., Q.S.W., L.S., M.A.B., C.S., T.J.W., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | - Marcia A Blair
- Medicine (T.Y., J.D.M., J.D.B., J-E.S., Q.S.W., L.S., M.A.B., C.S., T.J.W., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | | | - Evmorfia Petropoulou
- Cardiology Clinical Academic Group, Molecular and Clinical Sciences Institute, St George's, University of London and St George's University Hospitals National Health Service Foundation Trust, London, UK (E.P., Y.J.)
| | - Yalda Jamshidi
- Cardiology Clinical Academic Group, Molecular and Clinical Sciences Institute, St George's, University of London and St George's University Hospitals National Health Service Foundation Trust, London, UK (E.P., Y.J.)
| | - Mark D Benson
- Cardiovascular Research Center (E.J.B., M.D.B., M.J.K., R.E.G.), Beth Israel Deaconess Hospital, Boston, MA
- Division of Cardiovascular Medicine, Brigham and Women's Hospital, Boston, MA (M.D.B.)
| | - Michelle J Keyes
- Cardiovascular Research Center (E.J.B., M.D.B., M.J.K., R.E.G.), Beth Israel Deaconess Hospital, Boston, MA
| | - Debby Ngo
- Division of Pulmonary and Cardiovascular Medicine (D.N., R.E.G.), Beth Israel Deaconess Hospital, Boston, MA
| | | | - Qiong Yang
- Boston University School of Medicine, MA (R.S.V., Q.Y.)
| | - Robert E Gerszten
- Cardiovascular Research Center (E.J.B., M.D.B., M.J.K., R.E.G.), Beth Israel Deaconess Hospital, Boston, MA
- Division of Pulmonary and Cardiovascular Medicine (D.N., R.E.G.), Beth Israel Deaconess Hospital, Boston, MA
| | - Christian Shaffer
- Medicine (T.Y., J.D.M., J.D.B., J-E.S., Q.S.W., L.S., M.A.B., C.S., T.J.W., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | - Shan Parikh
- Departments of Pharmacology (K.R.B., A.M.G., D.O.K., K.K., J-E.S., C.C.C., Q.S.W., S.P., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | | | | | - Ivan P Moskowitz
- Departments of Pediatrics, Pathology, and Human Genetics, University of Chicago, IL (J.D.S., I.P.M.)
| | - John D York
- Biochemistry (A.T.H., J.D.Y.), Vanderbilt University, Nashville, TN
| | - Thomas J Wang
- Medicine (T.Y., J.D.M., J.D.B., J-E.S., Q.S.W., L.S., M.A.B., C.S., T.J.W., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | - Bjorn C Knollmann
- Departments of Pharmacology (K.R.B., A.M.G., D.O.K., K.K., J-E.S., C.C.C., Q.S.W., S.P., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
- Medicine (T.Y., J.D.M., J.D.B., J-E.S., Q.S.W., L.S., M.A.B., C.S., T.J.W., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | - Dan M Roden
- Departments of Pharmacology (K.R.B., A.M.G., D.O.K., K.K., J-E.S., C.C.C., Q.S.W., S.P., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
- Medicine (T.Y., J.D.M., J.D.B., J-E.S., Q.S.W., L.S., M.A.B., C.S., T.J.W., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
- Biomedical Informatics (Q.S.W., D.M.R.), Vanderbilt University, Nashville, TN
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Ottolia M, John S, Hazan A, Goldhaber JI. The Cardiac Na + -Ca 2+ Exchanger: From Structure to Function. Compr Physiol 2021; 12:2681-2717. [PMID: 34964124 DOI: 10.1002/cphy.c200031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Ca2+ homeostasis is essential for cell function and survival. As such, the cytosolic Ca2+ concentration is tightly controlled by a wide number of specialized Ca2+ handling proteins. One among them is the Na+ -Ca2+ exchanger (NCX), a ubiquitous plasma membrane transporter that exploits the electrochemical gradient of Na+ to drive Ca2+ out of the cell, against its concentration gradient. In this critical role, this secondary transporter guides vital physiological processes such as Ca2+ homeostasis, muscle contraction, bone formation, and memory to name a few. Herein, we review the progress made in recent years about the structure of the mammalian NCX and how it relates to function. Particular emphasis will be given to the mammalian cardiac isoform, NCX1.1, due to the extensive studies conducted on this protein. Given the degree of conservation among the eukaryotic exchangers, the information highlighted herein will provide a foundation for our understanding of this transporter family. We will discuss gene structure, alternative splicing, topology, regulatory mechanisms, and NCX's functional role on cardiac physiology. Throughout this article, we will attempt to highlight important milestones in the field and controversial topics where future studies are required. © 2021 American Physiological Society. Compr Physiol 12:1-37, 2021.
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Affiliation(s)
- Michela Ottolia
- Department of Anesthesiology and Perioperative Medicine, Division of Molecular Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Scott John
- Department of Medicine (Cardiology), UCLA, Los Angeles, California, USA
| | - Adina Hazan
- Smidt Heart Institute, Cedars Sinai Medical Center, Los Angeles, California, USA
| | - Joshua I Goldhaber
- Smidt Heart Institute, Cedars Sinai Medical Center, Los Angeles, California, USA
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Chen L, He Y, Wang X, Ge J, Li H. Ventricular voltage-gated ion channels: Detection, characteristics, mechanisms, and drug safety evaluation. Clin Transl Med 2021; 11:e530. [PMID: 34709746 PMCID: PMC8516344 DOI: 10.1002/ctm2.530] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 07/23/2021] [Accepted: 07/26/2021] [Indexed: 02/06/2023] Open
Abstract
Cardiac voltage-gated ion channels (VGICs) play critical roles in mediating cardiac electrophysiological signals, such as action potentials, to maintain normal heart excitability and contraction. Inherited or acquired alterations in the structure, expression, or function of VGICs, as well as VGIC-related side effects of pharmaceutical drug delivery can result in abnormal cellular electrophysiological processes that induce life-threatening cardiac arrhythmias or even sudden cardiac death. Hence, to reduce possible heart-related risks, VGICs must be acknowledged as important targets in drug discovery and safety studies related to cardiac disease. In this review, we first summarize the development and application of electrophysiological techniques that are employed in cardiac VGIC studies alone or in combination with other techniques such as cryoelectron microscopy, optical imaging and optogenetics. Subsequently, we describe the characteristics, structure, mechanisms, and functions of various well-studied VGICs in ventricular myocytes and analyze their roles in and contributions to both physiological cardiac excitability and inherited cardiac diseases. Finally, we address the implications of the structure and function of ventricular VGICs for drug safety evaluation. In summary, multidisciplinary studies on VGICs help researchers discover potential targets of VGICs and novel VGICs in heart, enrich their knowledge of the properties and functions, determine the operation mechanisms of pathological VGICs, and introduce groundbreaking trends in drug therapy strategies, and drug safety evaluation.
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Affiliation(s)
- Lulan Chen
- Department of Cardiology, Shanghai Institute of Cardiovascular DiseasesShanghai Xuhui District Central Hospital & Zhongshan‐xuhui Hospital, Zhongshan Hospital, Fudan UniversityShanghaiChina
| | - Yue He
- Department of CardiologyShanghai Xuhui District Central Hospital & Zhongshan‐xuhui HospitalShanghaiChina
| | - Xiangdong Wang
- Institute of Clinical Science, Zhongshan HospitalFudan UniversityShanghaiChina
| | - Junbo Ge
- Department of Cardiology, Shanghai Institute of Cardiovascular DiseasesShanghai Xuhui District Central Hospital & Zhongshan‐xuhui Hospital, Zhongshan Hospital, Fudan UniversityShanghaiChina
| | - Hua Li
- Department of Cardiology, Shanghai Institute of Cardiovascular DiseasesShanghai Xuhui District Central Hospital & Zhongshan‐xuhui Hospital, Zhongshan Hospital, Fudan UniversityShanghaiChina
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7
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Kamga MVK, Reppel M, Hescheler J, Nguemo F. Modeling genetic cardiac channelopathies using induced pluripotent stem cells - Status quo from an electrophysiological perspective. Biochem Pharmacol 2021; 192:114746. [PMID: 34461117 DOI: 10.1016/j.bcp.2021.114746] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/24/2021] [Accepted: 08/24/2021] [Indexed: 12/15/2022]
Abstract
Long QT syndrome (LQTS), Brugada syndrome (BrS), and catecholaminergic polymorphic ventricular tachycardia (CPVT) are genetic diseases of the heart caused by mutations in specific cardiac ion channels and are characterized by paroxysmal arrhythmias, which can deteriorate into ventricular fibrillation. In LQTS3 and BrS different mutations in the SCN5A gene lead to a gain-or a loss-of-function of the voltage-gated sodium channel Nav1.5, respectively. Although sharing the same gene mutation, these syndromes are characterized by different clinical manifestations and functional perturbations and in some cases even present an overlapping clinical phenotype. Several studies have shown that Na+ current abnormalities in LQTS3 and BrS can also cause Ca2+-signaling aberrancies in cardiomyocytes (CMs). Abnormal Ca2+ homeostasis is also the main feature of CPVT which is mostly caused by heterozygous mutations in the RyR2 gene. Large numbers of disease-causing mutations were identified in RyR2 and SCN5A but it is not clear how different variants in the SCN5A gene produce different clinical syndromes and if in CPVT Ca2+ abnormalities and drug sensitivities vary depending on the mutation site in the RyR2. These questions can now be addressed by using patient-specific in vitro models of these diseases based on induced pluripotent stem cells (iPSCs). In this review, we summarize different insights gained from these models with a focus on electrophysiological perturbations caused by different ion channel mutations and discuss how will this knowledge help develop better stratification and more efficient personalized therapies for these patients.
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Affiliation(s)
- Michelle Vanessa Kapchoup Kamga
- Center for Physiology and Pathophysiology, Institute for Neurophysiology, Medical Faculty, University of Cologne, 50931 Cologne, Germany
| | - Michael Reppel
- Center for Physiology and Pathophysiology, Institute for Neurophysiology, Medical Faculty, University of Cologne, 50931 Cologne, Germany; Praxis für Kardiologie und Angiologie, Landsberg am Lech, Germany
| | - Jürgen Hescheler
- Center for Physiology and Pathophysiology, Institute for Neurophysiology, Medical Faculty, University of Cologne, 50931 Cologne, Germany
| | - Filomain Nguemo
- Center for Physiology and Pathophysiology, Institute for Neurophysiology, Medical Faculty, University of Cologne, 50931 Cologne, Germany.
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Doisne N, Grauso M, Mougenot N, Clergue M, Souil C, Coulombe A, Guicheney P, Neyroud N. In vivo Dominant-Negative Effect of an SCN5A Brugada Syndrome Variant. Front Physiol 2021; 12:661413. [PMID: 34122134 PMCID: PMC8195286 DOI: 10.3389/fphys.2021.661413] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 04/21/2021] [Indexed: 12/23/2022] Open
Abstract
Loss-of-function mutations in the cardiac Na+ channel α-subunit Nav1.5, encoded by SCN5A, cause Brugada syndrome (BrS), a hereditary disease characterized by sudden cardiac death due to ventricular fibrillation. We previously evidenced in vitro the dominant-negative effect of the BrS Nav1.5-R104W variant, inducing retention of wild-type (WT) channels and leading to a drastic reduction of the resulting Na+ current (INa). To explore this dominant-negative effect in vivo, we created a murine model using adeno-associated viruses (AAVs).
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Affiliation(s)
- Nicolas Doisne
- INSERM, UMR_S 1166 ICAN, Paris, France.,UMR_S 1166, Faculté de Médecine Pitié-Salpêtrière, Sorbonne Université, Paris, France
| | - Marta Grauso
- INSERM, UMR_S 1166 ICAN, Paris, France.,UMR_S 1166, Faculté de Médecine Pitié-Salpêtrière, Sorbonne Université, Paris, France
| | - Nathalie Mougenot
- INSERM, UMR_S 1166 ICAN, Paris, France.,UMR_S 1166, Faculté de Médecine Pitié-Salpêtrière, Sorbonne Université, Paris, France.,UMS_28, Sorbonne Université, Paris, France
| | - Michel Clergue
- INSERM, UMR_S 1166 ICAN, Paris, France.,UMR_S 1166, Faculté de Médecine Pitié-Salpêtrière, Sorbonne Université, Paris, France
| | - Charlotte Souil
- INSERM, UMR_S 1166 ICAN, Paris, France.,UMR_S 1166, Faculté de Médecine Pitié-Salpêtrière, Sorbonne Université, Paris, France
| | - Alain Coulombe
- INSERM, UMR_S 1166 ICAN, Paris, France.,UMR_S 1166, Faculté de Médecine Pitié-Salpêtrière, Sorbonne Université, Paris, France
| | - Pascale Guicheney
- INSERM, UMR_S 1166 ICAN, Paris, France.,UMR_S 1166, Faculté de Médecine Pitié-Salpêtrière, Sorbonne Université, Paris, France
| | - Nathalie Neyroud
- INSERM, UMR_S 1166 ICAN, Paris, France.,UMR_S 1166, Faculté de Médecine Pitié-Salpêtrière, Sorbonne Université, Paris, France
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Zheng Y, Wan X, Yang D, Ramirez-Navarro A, Liu H, Fu JD, Deschênes I. A Heart Failure-Associated SCN5A Splice Variant Leads to a Reduction in Sodium Current Through Coupled-Gating With the Wild-Type Channel. Front Physiol 2021; 12:661429. [PMID: 33828490 PMCID: PMC8019726 DOI: 10.3389/fphys.2021.661429] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 03/01/2021] [Indexed: 12/14/2022] Open
Abstract
Nav1.5, encoded by the gene SCN5A, is the predominant voltage-gated sodium channel expressed in the heart. It initiates the cardiac action potential and thus is crucial for normal heart rhythm and function. Dysfunctions in Nav1.5 have been involved in multiple congenital or acquired cardiac pathological conditions such as Brugada syndrome (BrS), Long QT Syndrome Type 3, and heart failure (HF), all of which can lead to sudden cardiac death (SCD) - one of the leading causes of death worldwide. Our lab has previously reported that Nav1.5 forms dimer channels with coupled gating. We also found that Nav1.5 BrS mutants can exert a dominant-negative (DN) effect and impair the function of wildtype (WT) channels through coupled-gating with the WT. It was previously reported that reduction in cardiac sodium currents (INa), observed in HF, could be due to the increased expression of an SCN5A splice variant - E28D, which results in a truncated sodium channel (Nav1.5-G1642X). In this study, we hypothesized that this SCN5A splice variant leads to INa reduction in HF through biophysical coupling with the WT. We showed that Nav1.5-G1642X is a non-functional channel but can interact with the WT, resulting in a DN effect on the WT channel. We found that both WT and the truncated channel Nav1.5-G1642X traffic at the cell surface, suggesting biophysical coupling. Indeed, we found that the DN effect can be abolished by difopein, an inhibitor of the biophysical coupling. Interestingly, the sodium channel polymorphism H558R, which has beneficial effect in HF patients, could also block the DN effect. In summary, the HF-associated splice variant Nav1.5-G1642X suppresses sodium currents in heart failure patients through a mechanism involving coupled-gating with the wildtype sodium channel.
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Affiliation(s)
- Yang Zheng
- Department of Physiology and Cell Biology, Frick Center for Heart Failure and Arrhythmias, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
| | - Xiaoping Wan
- Department of Physiology and Cell Biology, Frick Center for Heart Failure and Arrhythmias, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Dandan Yang
- Department of Physiology and Cell Biology, Frick Center for Heart Failure and Arrhythmias, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Angelina Ramirez-Navarro
- Department of Physiology and Cell Biology, Frick Center for Heart Failure and Arrhythmias, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Haiyan Liu
- Department of Physiology and Cell Biology, Frick Center for Heart Failure and Arrhythmias, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Ji-Dong Fu
- Department of Physiology and Cell Biology, Frick Center for Heart Failure and Arrhythmias, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Isabelle Deschênes
- Department of Physiology and Cell Biology, Frick Center for Heart Failure and Arrhythmias, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
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10
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Wang Z, Vermij SH, Sottas V, Shestak A, Ross-Kaschitza D, Zaklyazminskaya EV, Hudmon A, Pitt GS, Rougier JS, Abriel H. Calmodulin binds to the N-terminal domain of the cardiac sodium channel Na v1.5. Channels (Austin) 2020; 14:268-286. [PMID: 32815768 PMCID: PMC7515574 DOI: 10.1080/19336950.2020.1805999] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The cardiac voltage-gated sodium channel Nav1.5 conducts the rapid inward sodium current crucial for cardiomyocyte excitability. Loss-of-function mutations in its gene SCN5A are linked to cardiac arrhythmias such as Brugada Syndrome (BrS). Several BrS-associated mutations in the Nav1.5 N-terminal domain (NTD) exert a dominant-negative effect (DNE) on wild-type channel function, for which mechanisms remain poorly understood. We aim to contribute to the understanding of BrS pathophysiology by characterizing three mutations in the Nav1.5 NTD: Y87C-here newly identified-, R104W, and R121W. In addition, we hypothesize that the calcium sensor protein calmodulin is a new NTD binding partner. Recordings of whole-cell sodium currents in TsA-201 cells expressing WT and variant Nav1.5 showed that Y87C and R104W but not R121W exert a DNE on WT channels. Biotinylation assays revealed reduction in fully glycosylated Nav1.5 at the cell surface and in whole-cell lysates. Localization of Nav1.5 WT channel with the ER did not change in the presence of variants, as shown by transfected and stained rat neonatal cardiomyocytes. We demonstrated that calmodulin binds the Nav1.5 NTD using in silico modeling, SPOTS, pull-down, and proximity ligation assays. Calmodulin binding to the R121W variant and to a Nav1.5 construct missing residues 80-105, a predicted calmodulin-binding site, is impaired. In conclusion, we describe the new natural BrS Nav1.5 variant Y87C and present first evidence that calmodulin binds to the Nav1.5 NTD, which seems to be a determinant for the DNE.
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Affiliation(s)
- Zizun Wang
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
| | - Sarah H. Vermij
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
| | - Valentin Sottas
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
- Department of Molecular and Cellular Genetics, Lonza BioPharma Ltd, Visp, Switzerland
| | - Anna Shestak
- Ibex, Petrovskiy Russian Scientific Center of Surgery, Moscow, Russia
| | | | | | - Andy Hudmon
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana, USA
| | - Geoffrey S. Pitt
- Cardiovascular Research Institute, Weill Cornell Medical College, New York, USA
| | | | - Hugues Abriel
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
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11
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Pearman CM, Denham NC, Mills RW, Ding WY, Modi SS, Hall MCS, Todd DM, Mahida S. Relationship between sodium channel function and clinical phenotype in SCN5A variants associated with Brugada syndrome. Hum Mutat 2020; 41:2195-2204. [PMID: 33131149 PMCID: PMC7756571 DOI: 10.1002/humu.24128] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 09/23/2020] [Accepted: 10/09/2020] [Indexed: 12/19/2022]
Abstract
The identification of a pathogenic SCN5A variant confers an increased risk of conduction defects and ventricular arrhythmias (VA) in Brugada syndrome (BrS). However, specific aspects of sodium channel function that influence clinical phenotype have not been defined. A systematic literature search identified SCN5A variants associated with BrS. Sodium current (INa) functional parameters (peak current, decay, steady‐state activation and inactivation, and recovery from inactivation) and clinical features (conduction abnormalities [CA], spontaneous VA or family history of sudden cardiac death [SCD], and spontaneous BrS electrocardiogram [ECG]) were extracted. A total of 561 SCN5A variants associated with BrS were identified, for which data on channel function and clinical phenotype were available in 142. In the primary analysis, no relationship was found between any aspect of channel function and CA, VA/SCD, or spontaneous BrS ECG pattern. Sensitivity analyses including only variants graded pathogenic or likely pathogenic suggested that reduction in peak current and positive shift in steady‐state activation were weakly associated with CA and VA/SCD, although sensitivity and specificity remained low. The relationship between in vitro assessment of channel function and BrS clinical phenotype is weak. The assessment of channel function does not enhance risk stratification. Caution is needed when extrapolating functional testing to the likelihood of variant pathogenicity.
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Affiliation(s)
- Charles M Pearman
- Department of Cardiac Electrophysiology and Inherited Cardiac Conditions, Liverpool Heart and Chest Hospital, Liverpool, UK.,Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Manchester Academic Health Science Centre, Core Technology Facility, University of Manchester, Manchester, UK
| | - Nathan C Denham
- Department of Cardiac Electrophysiology and Inherited Cardiac Conditions, Liverpool Heart and Chest Hospital, Liverpool, UK.,Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Manchester Academic Health Science Centre, Core Technology Facility, University of Manchester, Manchester, UK
| | - Robert W Mills
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, Massachusetts, USA
| | - Wern Y Ding
- Department of Cardiac Electrophysiology and Inherited Cardiac Conditions, Liverpool Heart and Chest Hospital, Liverpool, UK.,Liverpool Centre for Cardiovascular Science, Faculty of Life Sciences, University of Liverpool, Liverpool, UK
| | - Simon S Modi
- Department of Cardiac Electrophysiology and Inherited Cardiac Conditions, Liverpool Heart and Chest Hospital, Liverpool, UK
| | - Mark C S Hall
- Department of Cardiac Electrophysiology and Inherited Cardiac Conditions, Liverpool Heart and Chest Hospital, Liverpool, UK
| | - Derick M Todd
- Department of Cardiac Electrophysiology and Inherited Cardiac Conditions, Liverpool Heart and Chest Hospital, Liverpool, UK
| | - Saagar Mahida
- Department of Cardiac Electrophysiology and Inherited Cardiac Conditions, Liverpool Heart and Chest Hospital, Liverpool, UK.,Liverpool Centre for Cardiovascular Science, Faculty of Life Sciences, University of Liverpool, Liverpool, UK
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12
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Srettabunjong S, Eakkunnathum D, Thongnoppakhun W, Sripichai O. Association between SCN5A and sudden unexplained nocturnal death syndrome in Thai decedents: a case–control study. EGYPTIAN JOURNAL OF FORENSIC SCIENCES 2019. [DOI: 10.1186/s41935-019-0145-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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13
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Nof E, Vysochek L, Meisel E, Burashnikov E, Antzelevitch C, Clatot J, Beinart R, Luria D, Glikson M, Oz S. Mutations in Na V1.5 Reveal Calcium-Calmodulin Regulation of Sodium Channel. Front Physiol 2019; 10:700. [PMID: 31231243 PMCID: PMC6560087 DOI: 10.3389/fphys.2019.00700] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 05/20/2019] [Indexed: 12/02/2022] Open
Abstract
Mutations in the SCN5A gene, encoding the cardiac voltage-gated sodium channel NaV1.5, are associated with inherited cardiac arrhythmia and conduction disease. Ca2+-dependent mechanisms and the involvement of β-subunit (NaVβ) in NaV1.5 regulation are not fully understood. A patient with severe sinus-bradycardia and cardiac conduction-disease was genetically evaluated and compound heterozygosity in the SCN5A gene was found. Mutations were identified in the cytoplasmic DIII-IV linker (K1493del) and the C-terminus (A1924T) of NaV1.5, both are putative CaM-binding domains. These mutants were functionally studied in human embryonic kidney (HEK) cells and HL-1 cells using whole-cell patch clamp technique. Calmodulin (CaM) interaction and cell-surface expression of heterologously expressed NaV1.5 mutants were studied by pull-down and biotinylation assays. The mutation K1493del rendered NaV1.5 non-conductive. NaV1.5K1493del altered the gating properties of co-expressed functional NaV1.5, in a Ca2+ and NaVβ1-dependent manner. NaV1.5A1924T impaired NaVβ1-dependent gating regulation. Ca2+-dependent CaM-interaction with NaV1.5 was blunted in NaV1.5K1493del. Electrical charge substitution at position 1493 did not affect CaM-interaction and channel functionality. Arrhythmia and conduction-disease -associated mutations revealed Ca2+-dependent gating regulation of NaV1.5 channels. Our results highlight the role of NaV1.5 DIII-IV linker in the CaM-binding complex and channel function, and suggest that the Ca2+-sensing machinery of NaV1.5 involves NaVβ1.
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Affiliation(s)
- Eyal Nof
- Heart Center, Sheba Medical Center, Ramat Gan, Israel.,Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | | | - Eshcar Meisel
- Heart Center, Sheba Medical Center, Ramat Gan, Israel.,Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Elena Burashnikov
- Lankenau Institute for Medical Research, Wynnewood, PA, United States
| | - Charles Antzelevitch
- Lankenau Institute for Medical Research, Wynnewood, PA, United States.,Lankenau Heart Institute, Wynnewood, PA, United States.,Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, United States
| | - Jerome Clatot
- Lankenau Institute for Medical Research, Wynnewood, PA, United States
| | - Roy Beinart
- Heart Center, Sheba Medical Center, Ramat Gan, Israel.,Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - David Luria
- Heart Center, Sheba Medical Center, Ramat Gan, Israel
| | - Michael Glikson
- Heart Center, Sheba Medical Center, Ramat Gan, Israel.,Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Shimrit Oz
- Heart Center, Sheba Medical Center, Ramat Gan, Israel
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14
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Clatot J, Zheng Y, Girardeau A, Liu H, Laurita KR, Marionneau C, Deschênes I. Mutant voltage-gated Na + channels can exert a dominant negative effect through coupled gating. Am J Physiol Heart Circ Physiol 2018; 315:H1250-H1257. [PMID: 30118344 PMCID: PMC6297814 DOI: 10.1152/ajpheart.00721.2017] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 07/13/2018] [Accepted: 08/08/2018] [Indexed: 11/22/2022]
Abstract
Mutations in voltage-gated Na+ channels have been linked to several channelopathies leading to a wide variety of diseases including cardiac arrhythmias, epilepsy, and myotonia. We have previously demonstrated that voltage-gated Na+ channel (Nav)1.5 trafficking-deficient mutant channels could lead to a dominant negative effect by impairing trafficking of the wild-type (WT) channel. We also reported that voltage-gated Na+ channels associate as dimers with coupled gating properties. Here, we hypothesized that the dominant negative effect of mutant Na+ channels could also occur through coupled gating. This was tested using cell surface biotinylation and single channel recordings to measure the gating probability and coupled gating of the dimers. As previously reported, coexpression of Nav1.5-L325R with WT channels led to a dominant negative effect, as reflected by a 75% reduction in current density. Surprisingly, cell surface biotinylation showed that Nav1.5-L325R mutant is capable of trafficking, with 40% of Nav1.5-L325R reaching the cell surface when expressed alone. Importantly, even though a dominant negative effect on the Na+ current is observed when WT and Nav1.5-L325R are expressed together, the total Nav channel cell surface expression was not significantly altered compared with WT channels alone. Thus, the trafficking deficiency could not explain the 75% decrease in inward Na+ current. Interestingly, single channel recordings showed that Nav1.5-L325R exerted a dominant negative effect on the WT channel at the gating level. Both coupled gating and gating probability of WT:L325R dimers were drastically impaired. We conclude that dominant negative suppression exerted by Nav1.5 mutants can also be caused by impairing the WT gating probability, a mechanism resulting from the dimerization and coupled gating of voltage-gated Na+ channel α-subunits. NEW & NOTEWORTHY The presence of dominant negative mutations in the Na+ channel gene leading to Brugada syndrome was supported by our recent findings that Na+ channel α-subunits form dimers. Up until now, the dominant negative effect was thought to be caused by the interaction of the wild-type Na+ channel with trafficking-deficient mutant channels. However, the present study demonstrates that coupled gating of voltage-gated Na+ channels can also be responsible for the dominant negative effect leading to arrhythmias.
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Affiliation(s)
- Jérôme Clatot
- Heart and Vascular Research Center, Department of Medicine, MetroHealth Campus, Case Western Reserve University , Cleveland, Ohio
| | - Yang Zheng
- Heart and Vascular Research Center, Department of Medicine, MetroHealth Campus, Case Western Reserve University , Cleveland, Ohio
| | - Aurore Girardeau
- L'Institut du Thorax, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Université de Nantes, Nantes , France
| | - Haiyan Liu
- Heart and Vascular Research Center, Department of Medicine, MetroHealth Campus, Case Western Reserve University , Cleveland, Ohio
| | - Kenneth R Laurita
- Heart and Vascular Research Center, Department of Medicine, MetroHealth Campus, Case Western Reserve University , Cleveland, Ohio
| | - Céline Marionneau
- L'Institut du Thorax, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Université de Nantes, Nantes , France
| | - Isabelle Deschênes
- Heart and Vascular Research Center, Department of Medicine, MetroHealth Campus, Case Western Reserve University , Cleveland, Ohio
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15
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Denham NC, Pearman CM, Ding WY, Waktare J, Gupta D, Snowdon R, Hall M, Cooper R, Modi S, Todd D, Mahida S. Systematic re-evaluation of SCN5A variants associated with Brugada syndrome. J Cardiovasc Electrophysiol 2018; 30:118-127. [PMID: 30203441 DOI: 10.1111/jce.13740] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 09/01/2018] [Accepted: 09/07/2018] [Indexed: 12/19/2022]
Abstract
BACKGROUND A large number of SCN5A variants have been reported to underlie Brugada syndrome (BrS). However, the evidence supporting individual variants is highly heterogeneous. OBJECTIVE We systematically re-evaluated all SCN5A variants reported in BrS using the 2015 American college of medical genetics and genomics and the association for molecular pathology (ACMG-AMP) guidelines. METHODS A PubMed/Embase search was performed to identify all reported SCN5A variants in BrS. Standardized bioinformatic re-analysis (SIFT, PolyPhen, Mutation Taster, Mutation assessor, FATHMM, GERP, PhyloP, and SiPhy) and re-evaluation of frequency in the gnomAD database were performed. Fourteen ACMG-AMP rules were deemed applicable for SCN5A variant analysis. RESULTS Four hundred and eighty unique SCN5A variants were identified, the majority of which 425 (88%) were coding variants. One hundred and fifty-six of 425 (37%) variants were classified as pathogenic/likely pathogenic. Two hundred and fifty-eight (60%) were classified as variants of uncertain significance, while a further 11 (3%) were classified as benign/likely benign. When considering the subset of variants that were considered "null" variants separately, 95% fulfilled criteria for pathogenicity/likely pathogenicity. In contrast, only 17% of missense variants fulfilled criteria for pathogenicity/likely pathogenicity. Importantly, however, only 25% of missense variants had available functional data, which was a major score driver for pathogenic classification. CONCLUSION Based on contemporary ACMG-AMP guidelines, only a minority of SCN5A variants implicated in BrS fulfill the criteria for pathogenicity or likely pathogenicity.
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Affiliation(s)
- Nathan C Denham
- Department of Cardiac Electrophysiology, Liverpool Heart and Chest Hospital, Liverpool, UK.,Department of Inherited Cardiac Diseases, Liverpool Heart and Chest Hospital, Liverpool, UK.,Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, UK
| | - Charles M Pearman
- Department of Cardiac Electrophysiology, Liverpool Heart and Chest Hospital, Liverpool, UK.,Department of Inherited Cardiac Diseases, Liverpool Heart and Chest Hospital, Liverpool, UK.,Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, UK
| | - Wern Yew Ding
- Department of Cardiac Electrophysiology, Liverpool Heart and Chest Hospital, Liverpool, UK
| | - Johan Waktare
- Department of Cardiac Electrophysiology, Liverpool Heart and Chest Hospital, Liverpool, UK
| | - Dhiraj Gupta
- Department of Cardiac Electrophysiology, Liverpool Heart and Chest Hospital, Liverpool, UK
| | - Richard Snowdon
- Department of Cardiac Electrophysiology, Liverpool Heart and Chest Hospital, Liverpool, UK.,Department of Inherited Cardiac Diseases, Liverpool Heart and Chest Hospital, Liverpool, UK
| | - Mark Hall
- Department of Cardiac Electrophysiology, Liverpool Heart and Chest Hospital, Liverpool, UK
| | - Robert Cooper
- Department of Inherited Cardiac Diseases, Liverpool Heart and Chest Hospital, Liverpool, UK
| | - Simon Modi
- Department of Cardiac Electrophysiology, Liverpool Heart and Chest Hospital, Liverpool, UK.,Department of Inherited Cardiac Diseases, Liverpool Heart and Chest Hospital, Liverpool, UK
| | - Derick Todd
- Department of Cardiac Electrophysiology, Liverpool Heart and Chest Hospital, Liverpool, UK.,Department of Inherited Cardiac Diseases, Liverpool Heart and Chest Hospital, Liverpool, UK
| | - Saagar Mahida
- Department of Cardiac Electrophysiology, Liverpool Heart and Chest Hospital, Liverpool, UK.,Department of Inherited Cardiac Diseases, Liverpool Heart and Chest Hospital, Liverpool, UK
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16
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Pérez-Hernández M, Matamoros M, Alfayate S, Nieto-Marín P, Utrilla RG, Tinaquero D, de Andrés R, Crespo T, Ponce-Balbuena D, Willis BC, Jiménez-Vazquez EN, Guerrero-Serna G, da Rocha AM, Campbell K, Herron TJ, Díez-Guerra FJ, Tamargo J, Jalife J, Caballero R, Delpón E. Brugada syndrome trafficking-defective Nav1.5 channels can trap cardiac Kir2.1/2.2 channels. JCI Insight 2018; 3:96291. [PMID: 30232268 DOI: 10.1172/jci.insight.96291] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 08/03/2018] [Indexed: 12/28/2022] Open
Abstract
Cardiac Nav1.5 and Kir2.1-2.3 channels generate Na (INa) and inward rectifier K (IK1) currents, respectively. The functional INa and IK1 interplay is reinforced by the positive and reciprocal modulation between Nav15 and Kir2.1/2.2 channels to strengthen the control of ventricular excitability. Loss-of-function mutations in the SCN5A gene, which encodes Nav1.5 channels, underlie several inherited arrhythmogenic syndromes, including Brugada syndrome (BrS). We investigated whether the presence of BrS-associated mutations alters IK1 density concomitantly with INa density. Results obtained using mouse models of SCN5A haploinsufficiency, and the overexpression of native and mutated Nav1.5 channels in expression systems - rat ventricular cardiomyocytes and human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) - demonstrated that endoplasmic reticulum (ER) trafficking-defective Nav1.5 channels significantly decreased IK1, since they did not positively modulate Kir2.1/2.2 channels. Moreover, Golgi trafficking-defective Nav1.5 mutants produced a dominant negative effect on Kir2.1/2.2 and thus an additional IK1 reduction. Moreover, ER trafficking-defective Nav1.5 channels can be partially rescued by Kir2.1/2.2 channels through an unconventional secretory route that involves Golgi reassembly stacking proteins (GRASPs). Therefore, cardiac excitability would be greatly affected in subjects harboring Nav1.5 mutations with Golgi trafficking defects, since these mutants can concomitantly trap Kir2.1/2.2 channels, thus unexpectedly decreasing IK1 in addition to INa.
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Affiliation(s)
- Marta Pérez-Hernández
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, and CIBER of Cardiovascular Diseases, Madrid, Spain
| | - Marcos Matamoros
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, and CIBER of Cardiovascular Diseases, Madrid, Spain
| | - Silvia Alfayate
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, and CIBER of Cardiovascular Diseases, Madrid, Spain
| | - Paloma Nieto-Marín
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, and CIBER of Cardiovascular Diseases, Madrid, Spain
| | - Raquel G Utrilla
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, and CIBER of Cardiovascular Diseases, Madrid, Spain
| | - David Tinaquero
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, and CIBER of Cardiovascular Diseases, Madrid, Spain
| | - Raquel de Andrés
- Departamento de Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (UAM-CSIC), Universidad Autónoma de Madrid, Madrid, Spain
| | - Teresa Crespo
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, and CIBER of Cardiovascular Diseases, Madrid, Spain
| | - Daniela Ponce-Balbuena
- Departments of Internal Medicine and Molecular and Integrative Physiology, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, USA
| | - B Cicero Willis
- Departments of Internal Medicine and Molecular and Integrative Physiology, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, USA
| | - Eric N Jiménez-Vazquez
- Departments of Internal Medicine and Molecular and Integrative Physiology, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, USA
| | - Guadalupe Guerrero-Serna
- Departments of Internal Medicine and Molecular and Integrative Physiology, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, USA
| | - Andre M da Rocha
- Departments of Internal Medicine and Molecular and Integrative Physiology, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, USA
| | - Katherine Campbell
- Departments of Internal Medicine and Molecular and Integrative Physiology, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, USA
| | - Todd J Herron
- Departments of Internal Medicine and Molecular and Integrative Physiology, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, USA
| | - F Javier Díez-Guerra
- Departamento de Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (UAM-CSIC), Universidad Autónoma de Madrid, Madrid, Spain
| | - Juan Tamargo
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, and CIBER of Cardiovascular Diseases, Madrid, Spain
| | - José Jalife
- Departments of Internal Medicine and Molecular and Integrative Physiology, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, USA.,Fundación Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Ricardo Caballero
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, and CIBER of Cardiovascular Diseases, Madrid, Spain
| | - Eva Delpón
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, and CIBER of Cardiovascular Diseases, Madrid, Spain
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17
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Veeraraghavan R, Hoeker GS, Alvarez-Laviada A, Hoagland D, Wan X, King DR, Sanchez-Alonso J, Chen C, Jourdan J, Isom LL, Deschenes I, Smyth JW, Gorelik J, Poelzing S, Gourdie RG. The adhesion function of the sodium channel beta subunit (β1) contributes to cardiac action potential propagation. eLife 2018; 7:37610. [PMID: 30106376 PMCID: PMC6122953 DOI: 10.7554/elife.37610] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 08/06/2018] [Indexed: 12/22/2022] Open
Abstract
Computational modeling indicates that cardiac conduction may involve ephaptic coupling – intercellular communication involving electrochemical signaling across narrow extracellular clefts between cardiomyocytes. We hypothesized that β1(SCN1B) –mediated adhesion scaffolds trans-activating NaV1.5 (SCN5A) channels within narrow (<30 nm) perinexal clefts adjacent to gap junctions (GJs), facilitating ephaptic coupling. Super-resolution imaging indicated preferential β1 localization at the perinexus, where it co-locates with NaV1.5. Smart patch clamp (SPC) indicated greater sodium current density (INa) at perinexi, relative to non-junctional sites. A novel, rationally designed peptide, βadp1, potently and selectively inhibited β1-mediated adhesion, in electric cell-substrate impedance sensing studies. βadp1 significantly widened perinexi in guinea pig ventricles, and selectively reduced perinexal INa, but not whole cell INa, in myocyte monolayers. In optical mapping studies, βadp1 precipitated arrhythmogenic conduction slowing. In summary, β1-mediated adhesion at the perinexus facilitates action potential propagation between cardiomyocytes, and may represent a novel target for anti-arrhythmic therapies.
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Affiliation(s)
- Rengasayee Veeraraghavan
- Virginia Tech Carilion Research Institute, Virginia Polytechnic University, Roanoke, United States.,School of Medicine, Virginia Polytechnic University, Roanoke, United States
| | - Gregory S Hoeker
- Virginia Tech Carilion Research Institute, Virginia Polytechnic University, Roanoke, United States.,School of Medicine, Virginia Polytechnic University, Roanoke, United States
| | | | - Daniel Hoagland
- Virginia Tech Carilion Research Institute, Virginia Polytechnic University, Roanoke, United States.,School of Medicine, Virginia Polytechnic University, Roanoke, United States
| | - Xiaoping Wan
- Heart and Vascular Research Center, MetroHealth Medical Center, Department of Medicine, Case Western Reserve University, Cleveland, United States
| | - D Ryan King
- Virginia Tech Carilion Research Institute, Virginia Polytechnic University, Roanoke, United States.,School of Medicine, Virginia Polytechnic University, Roanoke, United States.,Graduate Program in Translational Biology, Medicine and Health, Virginia Tech, Virginia, United States
| | - Jose Sanchez-Alonso
- Department of Myocardial Function, Imperial College London, London, United Kingdom
| | - Chunling Chen
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, United States
| | - Jane Jourdan
- Virginia Tech Carilion Research Institute, Virginia Polytechnic University, Roanoke, United States.,School of Medicine, Virginia Polytechnic University, Roanoke, United States
| | - Lori L Isom
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, United States
| | - Isabelle Deschenes
- Heart and Vascular Research Center, MetroHealth Medical Center, Department of Medicine, Case Western Reserve University, Cleveland, United States.,Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Unites States
| | - James W Smyth
- Virginia Tech Carilion Research Institute, Virginia Polytechnic University, Roanoke, United States.,School of Medicine, Virginia Polytechnic University, Roanoke, United States.,Department of Biological Sciences, College of Science, Blacksburg, United States
| | - Julia Gorelik
- Department of Myocardial Function, Imperial College London, London, United Kingdom
| | - Steven Poelzing
- Virginia Tech Carilion Research Institute, Virginia Polytechnic University, Roanoke, United States.,School of Medicine, Virginia Polytechnic University, Roanoke, United States.,Department of Biomedical Engineering and Mechanics, Virginia Polytechnic University, Blacksburg, United States
| | - Robert G Gourdie
- Virginia Tech Carilion Research Institute, Virginia Polytechnic University, Roanoke, United States.,School of Medicine, Virginia Polytechnic University, Roanoke, United States.,Department of Biomedical Engineering and Mechanics, Virginia Polytechnic University, Blacksburg, United States
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18
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Scumaci D, Oliva A, Concolino A, Curcio A, Fiumara CV, Tammè L, Campuzano O, Pascali VL, Coll M, Iglesias A, Berne P, Casu G, Olivo E, Ausania F, Ricci P, Indolfi C, Brugada J, Brugada R, Cuda G. Integration of "Omics" Strategies for Biomarkers Discovery and for the Elucidation of Molecular Mechanisms Underlying Brugada Syndrome. Proteomics Clin Appl 2018; 12:e1800065. [PMID: 29956481 DOI: 10.1002/prca.201800065] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 05/26/2018] [Indexed: 12/31/2022]
Abstract
PURPOSE The Brugada syndrome (BrS) is a severe inherited cardiac disorder. Given the high genetic and phenotypic heterogeneity of this disease, three different "omics" approaches are integrated in a synergic way to elucidate the molecular mechanisms underlying the pathophysiology of BrS as well as for identifying reliable diagnostic/prognostic markers. EXPERIMENTAL DESIGN The profiling of plasma Proteome and MiRNome is perfomed in a cohort of Brugada patients that were preliminary subjected to genomic analysis to assess a peculiar gene mutation profile. RESULTS The integrated analysis of "omics" data unveiled a cooperative activity of mutated genes, deregulated miRNAs and proteins in orchestrating transcriptional and post-translational events that are critical determining factors for the development of the Brugada pattern. CONCLUSIONS AND CLINICAL RELEVANCE This study provides the basis to shed light on the specific molecular fingerprints underlying BrS development and to gain further insights on the pathogenesis of this life-threatening cardiac disease.
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Affiliation(s)
- Domenica Scumaci
- Laboratory of Proteomics, Research Center of Advanced Biochemistry and Molecular Biology, Department of Experimental and Clinical Medicine, Magna Graecia University of Catanzaro, 88100, Catanzaro, Italy
| | - Antonio Oliva
- Fondazione Policlinico A. Gemelli IRCCS, Roma, Università Cattolica del Sacro Cuore, Large Francesco Vito 1, 00168, Rome, Italy
| | - Antonio Concolino
- Laboratory of Proteomics, Research Center of Advanced Biochemistry and Molecular Biology, Department of Experimental and Clinical Medicine, Magna Graecia University of Catanzaro, 88100, Catanzaro, Italy
| | - Antonio Curcio
- Division of Cardiology, Department of Medical and Surgical Science, University "Magna Graecia" of Catanzaro, 88100, Catanzaro, Italy
| | - Claudia Vincenza Fiumara
- Laboratory of Proteomics, Research Center of Advanced Biochemistry and Molecular Biology, Department of Experimental and Clinical Medicine, Magna Graecia University of Catanzaro, 88100, Catanzaro, Italy
| | - Laura Tammè
- Laboratory of Proteomics, Research Center of Advanced Biochemistry and Molecular Biology, Department of Experimental and Clinical Medicine, Magna Graecia University of Catanzaro, 88100, Catanzaro, Italy
| | - Oscar Campuzano
- Cardiovascular Genetics Center, Gencardio Institut d'Investigacions Biomèdiques de Girona,, 17290, Girona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV) 17007, Girona, Spain.,Department of Medical Sciences, School of Medicine, University of Girona, 17004, Girona, Spain
| | - Vincenzo L Pascali
- Fondazione Policlinico A. Gemelli IRCCS, Roma, Università Cattolica del Sacro Cuore, Large Francesco Vito 1, 00168, Rome, Italy
| | - Monica Coll
- Cardiovascular Genetics Center, Gencardio Institut d'Investigacions Biomèdiques de Girona,, 17290, Girona, Spain
| | - Anna Iglesias
- Cardiovascular Genetics Center, Gencardio Institut d'Investigacions Biomèdiques de Girona,, 17290, Girona, Spain
| | - Paola Berne
- Unità Operativa Complessa di Cardiologia Ospedale "San Francesco", 08100, Nuoro, Italy
| | - Gavino Casu
- Unità Operativa Complessa di Cardiologia Ospedale "San Francesco", 08100, Nuoro, Italy
| | - Erika Olivo
- Laboratory of Proteomics, Research Center of Advanced Biochemistry and Molecular Biology, Department of Experimental and Clinical Medicine, Magna Graecia University of Catanzaro, 88100, Catanzaro, Italy
| | - Francesco Ausania
- Fondazione Policlinico A. Gemelli, IRCCS, Università Cattolica del Sacro Cuore, Roma
| | - Pietrantonio Ricci
- Department of Medical Sciences, School of Medicine, University of Girona, 17004, Girona, Spain.,Institute of Legal Medicine, University "Magna Graecia" of Catanzaro, 88100, Catanzaro, Italy
| | - Ciro Indolfi
- Division of Cardiology, Department of Medical and Surgical Science, University "Magna Graecia" of Catanzaro, 88100, Catanzaro, Italy
| | - Josep Brugada
- Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV) 17007, Girona, Spain.,Arrhythmia's Unit, Hospital Clinic, 08036, Barcelona, Spain
| | - Ramon Brugada
- Cardiovascular Genetics Center, Gencardio Institut d'Investigacions Biomèdiques de Girona,, 17290, Girona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV) 17007, Girona, Spain.,Department of Medical Sciences, School of Medicine, University of Girona, 17004, Girona, Spain.,Cardiology Service, Hospital Josep Trueta, 17007, Girona, Spain
| | - Giovanni Cuda
- Laboratory of Proteomics, Research Center of Advanced Biochemistry and Molecular Biology, Department of Experimental and Clinical Medicine, Magna Graecia University of Catanzaro, 88100, Catanzaro, Italy
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19
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Liu J, Bayer JD, Aschar-Sobbi R, Wauchop M, Spears D, Gollob M, Vigmond EJ, Tsushima R, Backx PH, Chauhan VS. Complex interactions in a novel SCN5A compound mutation associated with long QT and Brugada syndrome: Implications for Na+ channel blocking pharmacotherapy for de novo conduction disease. PLoS One 2018; 13:e0197273. [PMID: 29791480 PMCID: PMC5965851 DOI: 10.1371/journal.pone.0197273] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 04/30/2018] [Indexed: 11/29/2022] Open
Abstract
Background The SCN5A mutation, P1332L, is linked to a malignant form of congenital long QT syndrome, type 3 (LQT3), and affected patients are highly responsive to the Na+ channel blocking drug, mexiletine. In contrast, A647D is an atypical SCN5A mutation causing Brugada syndrome. An asymptomatic male with both P1332L and A647D presented with varying P wave/QRS aberrancy and mild QTc prolongation which did not shorten measurably with mexiletine. Objective We characterized the biophysical properties of P1332L, A647D and wild-type (WT) Na+ channels as well as their combinations in order to understand our proband’s phenotype and to guide mexilitine therapy. Methods Na+ channel biophysics and mexilitine-binding kinetics were assessed using heterologous expression studies in CHO-K1 cells and human ventricular myocyte modeling. Results Compared to WT, P1332L channels displayed a hyperpolarizing shift in inactivation, slower inactivation and prominent late Na+ currents (INa). While A647D had no effect on the biophysical properties of INa, it reduced peak and late INa density when co-expressed with either WT or P1332L. Additionally, while P1332L channels had greater sensitivity to block by mexiletine compared to WT, this was reduced in the presence of A647D. Modelling studies revealed that mixing P1332L with A647D channels, action potential durations were shortened compared to P1332L, while peak INa was reduced compared to either A647D coexpressing with WT or WT alone. Conclusions While A647D mitigates the lethal LQT3 phenotype seen with P1332L, it also reduces mexilitine sensitivity and decreases INa density. These results explain our proband’s mild repolarization abnormality and prominent conduction defect in the atria and ventricles, but also suggest that expression of P1332L with A647D yields a novel disease phenotype for which mexiletine pharmacotherapy is no longer suitable.
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Affiliation(s)
- Jie Liu
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Jason D. Bayer
- Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University Foundation, Pessac, France
- University of Bordeaux, IMB, UMR 5251, Talance, France
| | | | - Marianne Wauchop
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Danna Spears
- Peter Munk Cardiac Center, Division of Cardiology, University Health Network, Toronto, Ontario, Canada
| | - Michael Gollob
- Peter Munk Cardiac Center, Division of Cardiology, University Health Network, Toronto, Ontario, Canada
| | - Edward J. Vigmond
- Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University Foundation, Pessac, France
- University of Bordeaux, IMB, UMR 5251, Talance, France
| | - Robert Tsushima
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Peter H. Backx
- Department of Biology, York University, Toronto, Ontario, Canada
- Peter Munk Cardiac Center, Division of Cardiology, University Health Network, Toronto, Ontario, Canada
- * E-mail: (PB); (VC)
| | - Vijay S. Chauhan
- Peter Munk Cardiac Center, Division of Cardiology, University Health Network, Toronto, Ontario, Canada
- * E-mail: (PB); (VC)
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20
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Selga E, Sendfeld F, Martinez-Moreno R, Medine CN, Tura-Ceide O, Wilmut SI, Pérez GJ, Scornik FS, Brugada R, Mills NL. Sodium channel current loss of function in induced pluripotent stem cell-derived cardiomyocytes from a Brugada syndrome patient. J Mol Cell Cardiol 2018; 114:10-19. [PMID: 29024690 PMCID: PMC5807028 DOI: 10.1016/j.yjmcc.2017.10.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 09/15/2017] [Accepted: 10/04/2017] [Indexed: 12/24/2022]
Abstract
Brugada syndrome predisposes to sudden death due to disruption of normal cardiac ion channel function, yet our understanding of the underlying cellular mechanisms is incomplete. Commonly used heterologous expression models lack many characteristics of native cardiomyocytes and, in particular, the individual genetic background of a patient. Patient-specific induced pluripotent stem (iPS) cell-derived cardiomyocytes (iPS-CM) may uncover cellular phenotypical characteristics not observed in heterologous models. Our objective was to determine the properties of the sodium current in iPS-CM with a mutation in SCN5A associated with Brugada syndrome. Dermal fibroblasts from a Brugada syndrome patient with a mutation in SCN5A (c.1100G>A, leading to Nav1.5_p.R367H) were reprogrammed to iPS cells. Clones were characterized and differentiated to form beating clusters and sheets. Patient and control iPS-CM were structurally indistinguishable. Sodium current properties of patient and control iPS-CM were compared. These results were contrasted with those obtained in tsA201 cells heterologously expressing sodium channels with the same mutation. Patient-derived iPS-CM showed a 33.1-45.5% reduction in INa density, a shift in both activation and inactivation voltage-dependence curves, and faster recovery from inactivation. Co-expression of wild-type and mutant channels in tsA201 cells did not compromise channel trafficking to the membrane, but resulted in a reduction of 49.8% in sodium current density without affecting any other parameters. Cardiomyocytes derived from iPS cells from a Brugada syndrome patient with a mutation in SCN5A recapitulate the loss of function of sodium channel current associated with this syndrome; including pro-arrhythmic changes in channel function not detected using conventional heterologous expression systems.
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Affiliation(s)
- Elisabet Selga
- Cardiovascular Genetics Centre, Department of Medical Sciences, University of Girona, Girona, Spain; Institut d'Investigació Biomèdica de Girona (IDIBGI), Girona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Spain
| | - Franziska Sendfeld
- Scottish Centre for Regenerative Medicine, University of Edinburgh, United Kingdom; BHF/University Centre for Cardiovascular Sciences, University of Edinburgh, United Kingdom
| | - Rebecca Martinez-Moreno
- Cardiovascular Genetics Centre, Department of Medical Sciences, University of Girona, Girona, Spain; Institut d'Investigació Biomèdica de Girona (IDIBGI), Girona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Spain
| | - Claire N Medine
- Scottish Centre for Regenerative Medicine, University of Edinburgh, United Kingdom; BHF/University Centre for Cardiovascular Sciences, University of Edinburgh, United Kingdom
| | - Olga Tura-Ceide
- Department of Pulmonary Medicine, Hospital Clinic-Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias, University of Barcelona, Spain
| | - Sir Ian Wilmut
- Scottish Centre for Regenerative Medicine, University of Edinburgh, United Kingdom
| | - Guillermo J Pérez
- Cardiovascular Genetics Centre, Department of Medical Sciences, University of Girona, Girona, Spain; Institut d'Investigació Biomèdica de Girona (IDIBGI), Girona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Spain
| | - Fabiana S Scornik
- Cardiovascular Genetics Centre, Department of Medical Sciences, University of Girona, Girona, Spain; Institut d'Investigació Biomèdica de Girona (IDIBGI), Girona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Spain
| | - Ramon Brugada
- Cardiovascular Genetics Centre, Department of Medical Sciences, University of Girona, Girona, Spain; Institut d'Investigació Biomèdica de Girona (IDIBGI), Girona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Spain; Hospital Josep Trueta, Girona, Spain
| | - Nicholas L Mills
- BHF/University Centre for Cardiovascular Sciences, University of Edinburgh, United Kingdom.
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21
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Abstract
Fast opening and closing of voltage-gated sodium channels are crucial for proper propagation of the action potential through excitable tissues. Unlike potassium channels, sodium channel α-subunits are believed to form functional monomers. Yet, an increasing body of literature shows inconsistency with the traditional idea of a single α-subunit functioning as a monomer. Here we demonstrate that sodium channel α-subunits not only physically interact with each other but they actually assemble, function and gate as a dimer. We identify the region involved in the dimerization and demonstrate that 14-3-3 protein mediates the coupled gating. Importantly we show conservation of this mechanism among mammalian sodium channels. Our study not only shifts conventional paradigms in regard to sodium channel assembly, structure, and function but importantly this discovery of the mechanism involved in channel dimerization and biophysical coupling could open the door to new approaches and targets to treat and/or prevent sodium channelopathies. Voltage-gated sodium channels are expressed in excitable tissues and mutations have been linked to cardiac arrhythmias and channelopathies. Here the authors show that the sodium channel α-subunits interact to form a dimer and gate as dimer and that this functional dimerisation is conserved.
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22
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Jenewein T, Beckmann BM, Rose S, Osterhues HH, Schmidt U, Wolpert C, Miny P, Marschall C, Alders M, Bezzina CR, Wilde AAM, Kääb S, Kauferstein S. Genotype-phenotype dilemma in a case of sudden cardiac death with the E1053K mutation and a deletion in the SCN5A gene. Forensic Sci Int 2017; 275:187-194. [PMID: 28391114 DOI: 10.1016/j.forsciint.2017.02.038] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 01/13/2017] [Accepted: 02/23/2017] [Indexed: 12/19/2022]
Abstract
Mutations in the cardiac sodium channel gene SCN5A may result in various arrhythmia syndromes such as long QT syndrome type 3 (LQTS), Brugada syndrome (BrS), sick sinus syndrome (SSS), cardiac conduction diseases (CCD) and possibly dilated cardiomyopathy (DCM). In most of these inherited cardiac arrhythmia syndromes the phenotypical expression may range from asymptomatic phenotypes to sudden cardiac death (SCD). A 16-year-old female died during sleep. Autopsy did not reveal any explanation for her death and a genetic analysis was performed. A variant in the SCN5A gene (E1053K) that was previously described as disease causing was detected. Family members are carriers of the same E1053K variant, some even in a homozygous state, but surprisingly did not exhibit any pathological cardiac phenotype. Due to the lack of genotype-phenotype correlation further genetic studies were performed. A novel deletion in the promoter region of SCN5A was identified in the sudden death victim but was absent in other family members. These findings demonstrate the difficulties in interpreting the results of a family-based genetic screening and underline the phenotypic variability of SCN5A mutations.
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Affiliation(s)
- T Jenewein
- Institute of Legal Medicine, University of Frankfurt, Frankfurt am Main, Germany
| | - B M Beckmann
- University Hospital Munich, Department of Medicine I, Ludwig Maximilians University, Munich, Germany; German Cardiovascular Research Center (DZHK), Partner Site: Munich Heart Alliance, Munich, Germany
| | - S Rose
- Institute of Legal Medicine, University of Frankfurt, Frankfurt am Main, Germany
| | - H H Osterhues
- District Hospital Loerrach, Medical Clinic, Loerrach, Germany
| | - U Schmidt
- Institute of Legal Medicine, University Hospital of Freiburg, Freiburg, Germany
| | - C Wolpert
- Klinik für Innere Medizin, Cardiology Klinikum Ludwigsburg, Ludwigsburg, Germany
| | - P Miny
- Medical Genetics, University Hospital Basel, Basel, Switzerland
| | - C Marschall
- Center of Human Genetics and Laboratory Diagnostics, Martinsried, Germany
| | - M Alders
- Department of Clinical Genetics, Amsterdam Medical Center, Amsterdam, The Netherlands
| | - C R Bezzina
- Heart Centre, Department of Clinical and Experimental Cardiology, Amsterdam Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - A A M Wilde
- Heart Centre, Department of Clinical and Experimental Cardiology, Amsterdam Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders, Jeddah, Kingdom of Saudi Arabia
| | - S Kääb
- University Hospital Munich, Department of Medicine I, Ludwig Maximilians University, Munich, Germany; German Cardiovascular Research Center (DZHK), Partner Site: Munich Heart Alliance, Munich, Germany
| | - S Kauferstein
- Institute of Legal Medicine, University of Frankfurt, Frankfurt am Main, Germany.
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23
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Yan H, Wang C, Marx SO, Pitt GS. Calmodulin limits pathogenic Na+ channel persistent current. J Gen Physiol 2017; 149:277-293. [PMID: 28087622 PMCID: PMC5299624 DOI: 10.1085/jgp.201611721] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 12/13/2016] [Accepted: 12/19/2016] [Indexed: 01/29/2023] Open
Abstract
The molecular mechanisms controlling “persistent” current through voltage-gated Na+ channels are poorly understood. Yan et al. show that apocalmodulin binding to the intracellular C-terminal domain limits persistent Na+ flux and accelerates inactivation across the voltage-gated Na+ channel family. Increased “persistent” current, caused by delayed inactivation, through voltage-gated Na+ (NaV) channels leads to cardiac arrhythmias or epilepsy. The underlying molecular contributors to these inactivation defects are poorly understood. Here, we show that calmodulin (CaM) binding to multiple sites within NaV channel intracellular C-terminal domains (CTDs) limits persistent Na+ current and accelerates inactivation across the NaV family. Arrhythmia or epilepsy mutations located in NaV1.5 or NaV1.2 channel CTDs, respectively, reduce CaM binding either directly or by interfering with CTD–CTD interchannel interactions. Boosting the availability of CaM, thus shifting its binding equilibrium, restores wild-type (WT)–like inactivation in mutant NaV1.5 and NaV1.2 channels and likewise diminishes the comparatively large persistent Na+ current through WT NaV1.6, whose CTD displays relatively low CaM affinity. In cerebellar Purkinje neurons, in which NaV1.6 promotes a large physiological persistent Na+ current, increased CaM diminishes the persistent Na+ current, suggesting that the endogenous, comparatively weak affinity of NaV1.6 for apoCaM is important for physiological persistent current.
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Affiliation(s)
- Haidun Yan
- Ion Channel Research Unit, Duke University Medical Center, Durham, NC 27710
| | - Chaojian Wang
- Ion Channel Research Unit, Duke University Medical Center, Durham, NC 27710
| | - Steven O Marx
- Division of Cardiology, Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY 10032.,Department of Pharmacology, College of Physicians and Surgeons, Columbia University, New York, NY 10032
| | - Geoffrey S Pitt
- Ion Channel Research Unit, Duke University Medical Center, Durham, NC 27710
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24
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Kim DH, Lee SJ, Hahn SJ, Choi JS. Trifluoperazine blocks the human cardiac sodium channel, Na v1.5, independent of calmodulin. Biochem Biophys Res Commun 2016; 479:584-589. [PMID: 27666479 DOI: 10.1016/j.bbrc.2016.09.115] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 09/22/2016] [Indexed: 11/20/2022]
Abstract
Trifluoperazine is a phenothiazine derivative which is mainly used in the management of schizophrenia and also acts as a calmodulin inhibitor. We used the whole-cell patch-clamp technique to study the effects of trifluoperazine on human Nav1.5 (hNav1.5) currents expressed in HEK293 cells. The 50% inhibitory concentration of trifluoperazine was 15.5 ± 0.3 μM and the Hill coefficient was 2.7 ± 0.1. The effects of trifluoperazine on hNav1.5 were completely and repeatedly reversible after washout. Trifluoperazine caused depolarizing shifts in the activation and hyperpolarizing shifts in the steady-state inactivation of hNav1.5. Trifluoperazine also showed strong use-dependent inhibition of hNav1.5. The blockade of hNav1.5 currents by trifluoperazine was not affected by the whole cell dialysis of the calmodulin inhibitory peptide. Our results indicated that trifluoperazine blocks hNav1.5 current in concentration-, state- and use-dependent manners rather than via calmodulin inhibition.
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Affiliation(s)
- Dong-Hyun Kim
- College of Pharmacy, The Catholic University of Korea, Bucheon, Gyeonggi-do, 14662, South Korea
| | - Su-Jin Lee
- College of Pharmacy, The Catholic University of Korea, Bucheon, Gyeonggi-do, 14662, South Korea
| | - Sang June Hahn
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul, 06591, South Korea
| | - Jin-Sung Choi
- College of Pharmacy, The Catholic University of Korea, Bucheon, Gyeonggi-do, 14662, South Korea.
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25
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Sottas V, Abriel H. Negative-dominance phenomenon with genetic variants of the cardiac sodium channel Nav1.5. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:1791-8. [PMID: 26907222 DOI: 10.1016/j.bbamcr.2016.02.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 02/15/2016] [Accepted: 02/19/2016] [Indexed: 02/07/2023]
Abstract
During the past two decades, many pathological genetic variants in SCN5A, the gene encoding the pore-forming subunit of the cardiac (monomeric) sodium channel Na(v)1.5, have been described. Negative dominance is a classical genetic concept involving a "poison" mutant peptide that negatively interferes with the co-expressed wild-type protein, thus reducing its cellular function. This phenomenon has been described for genetic variants of multimeric K(+) channels, which mechanisms are well understood. Unexpectedly, several pathologic SCN5A variants that are linked to Brugada syndrome also demonstrate such a dominant-negative (DN) effect. The molecular determinants of these observations, however, are not yet elucidated. This review article summarizes recent findings that describe the mechanisms underlying the DN phenomenon of genetic variants of K(+), Ca(2+), Cl(-) and Na(+) channels, and in particular Brugada syndrome variants of Na(v)1.5. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.
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Affiliation(s)
- Valentin Sottas
- Department of Clinical Research, Ion Channel Research Group, University of Bern, Switzerland
| | - Hugues Abriel
- Department of Clinical Research, Ion Channel Research Group, University of Bern, Switzerland.
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Huang L, Tang S, Peng L, Chen Y, Cheng J. Molecular Autopsy of Desmosomal Protein Plakophilin-2 in Sudden Unexplained Nocturnal Death Syndrome. J Forensic Sci 2016; 61:687-91. [DOI: 10.1111/1556-4029.13027] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 06/20/2015] [Accepted: 07/03/2015] [Indexed: 01/28/2023]
Affiliation(s)
- Lei Huang
- Department of Forensic Pathology; Zhongshan School of Medicine; Sun Yat-sen University; Guangzhou 510080 China
- Department of Forensic Sciences; Faculty of Forensic Sciences; Guangdong Justice Police Vocational College; Guangzhou 510520 China
| | - Shuangbo Tang
- Department of Forensic Pathology; Zhongshan School of Medicine; Sun Yat-sen University; Guangzhou 510080 China
| | - Longyun Peng
- Department of Cardiology; The First Affiliated Hospital of Sun Yat-sen University; Guangzhou 510080 China
| | - Yili Chen
- Department of Cardiology; The First Affiliated Hospital of Sun Yat-sen University; Guangzhou 510080 China
| | - Jianding Cheng
- Department of Forensic Pathology; Zhongshan School of Medicine; Sun Yat-sen University; Guangzhou 510080 China
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Namadurai S, Yereddi NR, Cusdin FS, Huang CLH, Chirgadze DY, Jackson AP. A new look at sodium channel β subunits. Open Biol 2015; 5:140192. [PMID: 25567098 PMCID: PMC4313373 DOI: 10.1098/rsob.140192] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Voltage-gated sodium (Nav) channels are intrinsic plasma membrane proteins that initiate the action potential in electrically excitable cells. They are a major focus of research in neurobiology, structural biology, membrane biology and pharmacology. Mutations in Nav channels are implicated in a wide variety of inherited pathologies, including cardiac conduction diseases, myotonic conditions, epilepsy and chronic pain syndromes. Drugs active against Nav channels are used as local anaesthetics, anti-arrhythmics, analgesics and anti-convulsants. The Nav channels are composed of a pore-forming α subunit and associated β subunits. The β subunits are members of the immunoglobulin (Ig) domain family of cell-adhesion molecules. They modulate multiple aspects of Nav channel behaviour and play critical roles in controlling neuronal excitability. The recently published atomic resolution structures of the human β3 and β4 subunit Ig domains open a new chapter in the study of these molecules. In particular, the discovery that β3 subunits form trimers suggests that Nav channel oligomerization may contribute to the functional properties of some β subunits.
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Affiliation(s)
- Sivakumar Namadurai
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK
| | - Nikitha R Yereddi
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK
| | - Fiona S Cusdin
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK
| | | | - Dimitri Y Chirgadze
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK
| | - Antony P Jackson
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK
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Abstract
The structures of the cytosolic portion of voltage activated sodium channels (CTNav) in complexes with calmodulin and other effectors in the presence and the absence of calcium provide information about the mechanisms by which these effectors regulate channel activity. The most studied of these complexes, those of Nav1.2 and Nav1.5, show details of the conformations and the specific contacts that are involved in channel regulation. Another voltage activated sodium channel, Nav1.4, shows significant calcium dependent inactivation, while its homolog Nav1.5 does not. The available structures shed light on the possible localization of the elements responsible for this effect. Mutations in the genes of these 3 Nav channels are associated with several disease conditions: Nav1.2, neurological conditions; Nav1.4, syndromes involving skeletal muscle; and Nav1.5, cardiac arrhythmias. Many of these disease-specific mutations are located at the interfaces involving CTNav and its effectors.
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Affiliation(s)
- Sandra B Gabelli
- a Structural Enzymology and Thermodynamics Group; Department of Biophysics and Biophysical Chemistry , Johns Hopkins University School of Medicine , Baltimore , MD USA.,b Division of Cardiology; Department of Medicine, Johns Hopkins University School of Medicine ; Baltimore , MD USA.,c Department of Oncology ; Johns Hopkins University School of Medicine ; Baltimore , MD USA
| | - Jesse B Yoder
- a Structural Enzymology and Thermodynamics Group; Department of Biophysics and Biophysical Chemistry , Johns Hopkins University School of Medicine , Baltimore , MD USA
| | - Gordon F Tomaselli
- b Division of Cardiology; Department of Medicine, Johns Hopkins University School of Medicine ; Baltimore , MD USA
| | - L Mario Amzel
- a Structural Enzymology and Thermodynamics Group; Department of Biophysics and Biophysical Chemistry , Johns Hopkins University School of Medicine , Baltimore , MD USA
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Nav1.5 channels can reach the plasma membrane through distinct N-glycosylation states. Biochim Biophys Acta Gen Subj 2015; 1850:1215-23. [PMID: 25721215 DOI: 10.1016/j.bbagen.2015.02.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 01/26/2015] [Accepted: 02/16/2015] [Indexed: 02/06/2023]
Abstract
BACKGROUND Like many voltage-gated sodium channels, the cardiac isoform Nav1.5 is well known as a glycoprotein which necessarily undergoes N-glycosylation processing during its transit to the plasma membrane. In some cardiac disorders, especially the Brugada syndrome (BrS), mutations in Nav1.5 encoding gene lead to intracellular retention and consequently trafficking defect of these proteins. We used two BrS mutants as tools to clarify both Nav1.5 glycosylation states and associated secretory behaviors. METHODS Patch-clamp recordings and surface biotinylation assays of HEK293T cells expressing wild-type (WT) and/or mutant Nav1.5 proteins were performed to assess the impact of mutant co-expression on the membrane activity and localization of WT channels. Enzymatic deglycosylation assays and brefeldin A (BFA) treatments were also employed to further characterize recombinant and native Nav1.5 maturation. RESULTS The present data demonstrate that Nav1.5 channels mainly exist as two differentially glycosylated forms. We reveal that dominant negative effects induced by BrS mutants upon WT channel current result from the abnormal surface expression of the fully-glycosylated forms exclusively. Furthermore, we show that core-glycosylated channels can be found at the surface membrane of BFA-treated or untreated cells, but obviously without generating any sodium current. CONCLUSIONS Our findings provide evidence that native and recombinant Nav1.5 subunits are expressed as two distinct matured forms. Fully-glycosylated state of Nav1.5 seems to determine its functionality whereas core-glycosylated forms might be transported to the plasma membrane through an unconventional Golgi-independent secretory route. GENERAL SIGNIFICANCE This work highlights that N-linked glycosylation processing would be critical for Nav1.5 membrane trafficking and function.
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Gabelli SB, Boto A, HalperinKuhns V, Bianchet MA, Farinelli F, Aripirala S, Yoder J, Jakoncic J, Tomaselli GF, Amzel LM. Regulation of the NaV1.5 cytoplasmic domain by calmodulin. Nat Commun 2014; 5:5126. [PMID: 25370050 PMCID: PMC4223872 DOI: 10.1038/ncomms6126] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 09/02/2014] [Indexed: 12/23/2022] Open
Abstract
Voltage-gated sodium channels (Na(v)) underlie the rapid upstroke of action potentials in excitable tissues. Binding of channel-interactive proteins is essential for controlling fast and long-term inactivation. In the structure of the complex of the carboxy-terminal portion of Na(v)1.5 (CTNa(v)1.5) with calmodulin (CaM)-Mg(2+) reported here, both CaM lobes interact with the CTNa(v)1.5. On the basis of the differences between this structure and that of an inactivated complex, we propose that the structure reported here represents a non-inactivated state of the CTNa(v), that is, the state that is poised for activation. Electrophysiological characterization of mutants further supports the importance of the interactions identified in the structure. Isothermal titration calorimetry experiments show that CaM binds to CTNa(v)1.5 with high affinity. The results of this study provide unique insights into the physiological activation and the pathophysiology of Na(v) channels.
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Affiliation(s)
- Sandra B. Gabelli
- Structural Enzymology and Thermodynamics Group. Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, 725 N Wolfe St, WBSB 608, Baltimore, Maryland 21205, USA
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross Bldg. 844, Baltimore, MD 21205, USA
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Agedi Boto
- Structural Enzymology and Thermodynamics Group. Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, 725 N Wolfe St, WBSB 608, Baltimore, Maryland 21205, USA
| | - Victoria HalperinKuhns
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross Bldg. 844, Baltimore, MD 21205, USA
| | - Mario A. Bianchet
- Structural Enzymology and Thermodynamics Group. Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, 725 N Wolfe St, WBSB 608, Baltimore, Maryland 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, 600 N Wolfe St, Baltimore, MD 21287, USA
| | - Federica Farinelli
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross Bldg. 844, Baltimore, MD 21205, USA
| | - Srinivas Aripirala
- Structural Enzymology and Thermodynamics Group. Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, 725 N Wolfe St, WBSB 608, Baltimore, Maryland 21205, USA
| | - Jesse Yoder
- Structural Enzymology and Thermodynamics Group. Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, 725 N Wolfe St, WBSB 608, Baltimore, Maryland 21205, USA
| | - Jean Jakoncic
- Brookhaven National Laboratory, National Synchrotron Light Source, Upton, NY 11973
| | - Gordon F. Tomaselli
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross Bldg. 844, Baltimore, MD 21205, USA
| | - L. Mario Amzel
- Structural Enzymology and Thermodynamics Group. Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, 725 N Wolfe St, WBSB 608, Baltimore, Maryland 21205, USA
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Béziau DM, Barc J, O'Hara T, Le Gloan L, Amarouch MY, Solnon A, Pavin D, Lecointe S, Bouillet P, Gourraud JB, Guicheney P, Denjoy I, Redon R, Mabo P, le Marec H, Loussouarn G, Kyndt F, Schott JJ, Probst V, Baró I. Complex Brugada syndrome inheritance in a family harbouring compound SCN5A and CACNA1C mutations. Basic Res Cardiol 2014; 109:446. [PMID: 25341504 DOI: 10.1007/s00395-014-0446-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 09/19/2014] [Accepted: 10/09/2014] [Indexed: 12/19/2022]
Abstract
Brugada syndrome (BrS) is characterized by ST-segment elevation in the right precordial leads and is associated with increased risk of sudden cardiac death. We have recently reported families with BrS and SCN5A mutations where some affected members do not carry the familial mutation. We evaluated the involvement of additional genetic determinants for BrS in an affected family. We identified three distinct gene variants within a family presenting BrS (5 individuals), cardiac conduction defects (CCD, 3 individuals) and shortened QT interval (4 individuals). The first mutation is nonsense, p.Q1695*, lying within the SCN5A gene, which encodes for NaV1.5, the α-subunit of the cardiac Na(+) channel. The second mutation is missense, p.N300D, and alters the CACNA1C gene, which encodes the α-subunit CaV1.2 of the L-type cardiac Ca(2+) channel. The SCN5A mutation strictly segregates with CCD. Four out of the 5 BrS patients carry the CACNA1C variant, and three of them present shortened QT interval. One of the BrS patients carries none of these mutations but a rare variant located in the ABCC9 gene as well as his asymptomatic mother. Patch-clamp studies identified a loss-of-function of the mutated CaV1.2 channel. Western-blot experiments showed a global expression defect while increased mobility of CaV1.2 channels on cell surface was revealed by FRAP experiments. Finally, computer simulations of the two mutations recapitulated patient phenotypes. We report a rare CACNA1C mutation as causing BrS and/or shortened QT interval in a family also carrying a SCN5A stop mutation, but which does not segregate with BrS. This study underlies the complexity of BrS inheritance and its pre-symptomatic genetic screening interpretation.
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Affiliation(s)
- Delphine M Béziau
- INSERM, UMR 1087, l'institut du thorax, 8 Quai Moncousu, BP 70721, 44007, Nantes cedex 1, France
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van Hoeijen DA, Blom MT, Tan HL. Cardiac sodium channels and inherited electrophysiological disorders: an update on the pharmacotherapy. Expert Opin Pharmacother 2014; 15:1875-87. [PMID: 24992280 DOI: 10.1517/14656566.2014.936380] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
INTRODUCTION Since the recognition of inherited sodium (Na(+)) channel disease, the cardiac Na(+) channel has been extensively studied. Both loss-of-function and gain-of-function mutations of the cardiac Na(+) channel are associated with cardiac arrhythmia and sudden cardiac death. Pathophysiological mechanisms that may induce arrhythmia are unravelled and include alterations in biophysical properties due to the mutation in SCN5A, drug use and circumstantial factors. Insights into the mechanisms of inherited Na(+) channel disease may result in tailored therapy. However, due to the complexity of cardiac electrical activity and pathophysiological mechanisms, pharmacotherapy in cardiac Na(+) channel disease remains challenging. AREAS COVERED This review discusses various mechanisms involved in inherited Na(+) channel disorders, focussing on Brugada syndrome (Brs) and long QT syndrome type 3 (LQTS3). It aims to provide an overview of developments in pharmacotherapy, discussing both treatment and which drugs to avoid to prevent arrhythmia. EXPERT OPINION Altered biophysical properties of cardiac Na(+) channels are the basis of arrhythmias in patients with inherited Na(+) channel diseases such as BrS and LQTS3. The effects of such biophysical derangements are strongly modulated by concomitant factors. Tailored drug therapy is required to prevent arrhythmia and is best achieved by educating patients affected by Na(+) channel disorders.
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Affiliation(s)
- Daniel A van Hoeijen
- University of Amsterdam, Academic Medical Center, Department of Cardiology , P.O. Box 22660, 1100 DD, Amsterdam , The Netherlands +0031 20 566 3264 ; +0031 20 566 9131 ;
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Abriel H, Sottas V. Unexpected α-α interactions with NaV1.5 genetic variants in Brugada syndrome. CIRCULATION. CARDIOVASCULAR GENETICS 2014; 7:97-9. [PMID: 24736849 DOI: 10.1161/circgenetics.114.000590] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Hugues Abriel
- Ion Channel Research Group, Department of Clinical Research, University of Bern, Bern, Switzerland
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