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Gutiérrez LK, Moreno-Manuel AI, Jalife J. Kir2.1-Na V1.5 channelosome and its role in arrhythmias in inheritable cardiac diseases. Heart Rhythm 2024; 21:630-646. [PMID: 38244712 DOI: 10.1016/j.hrthm.2024.01.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 01/10/2024] [Accepted: 01/13/2024] [Indexed: 01/22/2024]
Abstract
Sudden cardiac death in children and young adults is a relatively rare but tragic event whose pathophysiology is unknown at the molecular level. Evidence indicates that the main cardiac sodium channel (NaV1.5) and the strong inward rectifier potassium channel (Kir2.1) physically interact and form macromolecular complexes (channelosomes) with common partners, including adapter, scaffolding, and regulatory proteins that help them traffic together to their eventual membrane microdomains. Most important, dysfunction of either or both ion channels has direct links to hereditary human diseases. For example, certain mutations in the KCNJ2 gene encoding the Kir2.1 protein result in Andersen-Tawil syndrome type 1 and alter both inward rectifier potassium and sodium inward currents. Similarly, trafficking-deficient mutations in the gene encoding the NaV1.5 protein (SCN5A) result in Brugada syndrome and may also disturb both inward rectifier potassium and sodium inward currents. Moreover, gain-of-function mutations in KCNJ2 result in short QT syndrome type 3, which is extremely rare but highly arrhythmogenic, and can modify Kir2.1-NaV1.5 interactions in a mutation-specific way, further highlighting the relevance of channelosomes in ion channel diseases. By expressing mutant proteins that interrupt or modify Kir2.1 or NaV1.5 function in animal models and patient-specific pluripotent stem cell-derived cardiomyocytes, investigators are defining for the first time the mechanistic framework of how mutation-induced dysregulation of the Kir2.1-NaV1.5 channelosome affects cardiac excitability, resulting in arrhythmias and sudden death in different cardiac diseases.
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Affiliation(s)
- Lilian K Gutiérrez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | | | - José Jalife
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain; CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain; Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan.
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2
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Cruz FM, Macías Á, Moreno-Manuel AI, Gutiérrez LK, Vera-Pedrosa ML, Martínez-Carrascoso I, Pérez PS, Robles JMR, Bermúdez-Jiménez FJ, Díaz-Agustín A, de Benito FM, Arias-Santiago S, Braza-Boils A, Martín-Martínez M, Gutierrez-Rodríguez M, Bernal JA, Zorio E, Jiménez-Jaimez J, Jalife J. Extracellular Kir2.1 C122Y Mutant Upsets Kir2.1-PIP 2 Bonds and Is Arrhythmogenic in Andersen-Tawil Syndrome. Circ Res 2024; 134:e52-e71. [PMID: 38497220 PMCID: PMC11009053 DOI: 10.1161/circresaha.123.323895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 02/29/2024] [Indexed: 03/19/2024]
Abstract
BACKGROUND Andersen-Tawil syndrome type 1 is a rare heritable disease caused by mutations in the gene coding the strong inwardly rectifying K+ channel Kir2.1. The extracellular Cys (cysteine)122-to-Cys154 disulfide bond in the channel structure is crucial for proper folding but has not been associated with correct channel function at the membrane. We evaluated whether a human mutation at the Cys122-to-Cys154 disulfide bridge leads to Kir2.1 channel dysfunction and arrhythmias by reorganizing the overall Kir2.1 channel structure and destabilizing its open state. METHODS We identified a Kir2.1 loss-of-function mutation (c.366 A>T; p.Cys122Tyr) in an ATS1 family. To investigate its pathophysiological implications, we generated an AAV9-mediated cardiac-specific mouse model expressing the Kir2.1C122Y variant. We employed a multidisciplinary approach, integrating patch clamping and intracardiac stimulation, molecular biology techniques, molecular dynamics, and bioluminescence resonance energy transfer experiments. RESULTS Kir2.1C122Y mice recapitulated the ECG features of ATS1 independently of sex, including corrected QT prolongation, conduction defects, and increased arrhythmia susceptibility. Isolated Kir2.1C122Y cardiomyocytes showed significantly reduced inwardly rectifier K+ (IK1) and inward Na+ (INa) current densities independently of normal trafficking. Molecular dynamics predicted that the C122Y mutation provoked a conformational change over the 2000-ns simulation, characterized by a greater loss of hydrogen bonds between Kir2.1 and phosphatidylinositol 4,5-bisphosphate than wild type (WT). Therefore, the phosphatidylinositol 4,5-bisphosphate-binding pocket was destabilized, resulting in a lower conductance state compared with WT. Accordingly, on inside-out patch clamping, the C122Y mutation significantly blunted Kir2.1 sensitivity to increasing phosphatidylinositol 4,5-bisphosphate concentrations. In addition, the Kir2.1C122Y mutation resulted in channelosome degradation, demonstrating temporal instability of both Kir2.1 and NaV1.5 proteins. CONCLUSIONS The extracellular Cys122-to-Cys154 disulfide bond in the tridimensional Kir2.1 channel structure is essential for the channel function. We demonstrate that breaking disulfide bonds in the extracellular domain disrupts phosphatidylinositol 4,5-bisphosphate-dependent regulation, leading to channel dysfunction and defects in Kir2.1 energetic stability. The mutation also alters functional expression of the NaV1.5 channel and ultimately leads to conduction disturbances and life-threatening arrhythmia characteristic of Andersen-Tawil syndrome type 1.
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Affiliation(s)
- Francisco M. Cruz
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | - Álvaro Macías
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | | | - Lilian K. Gutiérrez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | | | | | | | | | - Francisco J Bermúdez-Jiménez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
- Servicio de Cardiología, Hospital Universitario Virgen de las Nieves, Granada, Spain
- Instituto de Investigación Biosanitaria de Granada IBS, Granada, Spain
| | - Aitor Díaz-Agustín
- Instituto de Química Médica (IQM), Consejo Superior de Investigaciones Científicas (CSIC), 28006 Madrid, Spain
| | - Fernando Martínez de Benito
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Salvador Arias-Santiago
- Servicio de Dermatología Hospital Universitario Virgen de las Nieves
- Instituto de Investigación Biosanitaria de Granada IBS, Granada, Spain
| | - Aitana Braza-Boils
- Unit of Inherited Cardiomyopathies and Sudden Death (CAFAMUSME), Health Research Institute La Fe, La Fe Hospital, Valencia, Spain
- Cardiology Department, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Mercedes Martín-Martínez
- Instituto de Química Médica (IQM), Consejo Superior de Investigaciones Científicas (CSIC), 28006 Madrid, Spain
| | - Marta Gutierrez-Rodríguez
- Instituto de Química Médica (IQM), Consejo Superior de Investigaciones Científicas (CSIC), 28006 Madrid, Spain
| | - Juan A. Bernal
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Esther Zorio
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
- Unit of Inherited Cardiomyopathies and Sudden Death (CAFAMUSME), Health Research Institute La Fe, La Fe Hospital, Valencia, Spain
- Cardiology Department, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Juan Jiménez-Jaimez
- Servicio de Cardiología, Hospital Universitario Virgen de las Nieves, Granada, Spain
- Instituto de Investigación Biosanitaria de Granada IBS, Granada, Spain
| | - José Jalife
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
- Departments of Medicine and Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
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3
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Shi L, Nie B, Sha L, Ying K, Li J, Li G. Graphene Oxide-Mediated Regulation of Volume Exclusion and Wettability in Biomimetic Phosphorylation-Responsive Ionic Gates. NANO LETTERS 2023; 23:10326-10333. [PMID: 37931221 DOI: 10.1021/acs.nanolett.3c02924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
Replicating phosphorylation-responsive ionic gates via artificial fluidic systems is essential for biomolecular detection and cellular communication research. However, current approaches to governing the gates primarily rely on volume exclusion or surface charge modulation. To overcome this limitation and enhance ion transport controllability, we introduce graphene oxide (GO) into nanochannel systems, simultaneously regulating the volume exclusion and wettability. Moreover, inspired by (cAMP)-dependent protein kinase A (PKA)-regulated L-type Ca2+ channels, we employ peptides for phosphorylation which preserves them as nanoadhesives to coat nanochannels with GO. The coating boosts steric hindrance and diminishes wettability, creating a substantial ion conduction barrier, which represents a significant advancement in achieving precise ion transport regulation in abiotic nanochannels. Leveraging the mechanism, we also fabricated a sensitive biosensor for PKA activity detection and inhibition exploration. The combined regulation of volume exclusion and wettability offers an appealing strategy for controlled nanofluidic manipulation with promising biomedical applications in diagnosis and drug discovery.
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Affiliation(s)
- Liu Shi
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, P. R. China
| | - Beibei Nie
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, P. R. China
| | - Lingjun Sha
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, P. R. China
| | - Keqin Ying
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, P. R. China
| | - Jinlong Li
- The Second Hospital of Nanjing, Nanjing University of Chinese Medicine, Nanjing 210003, P. R. China
| | - Genxi Li
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, P. R. China
- Center for Molecular Recognition and Biosensing, School of Life Sciences, Shanghai University, Shanghai 200444, P. R. China
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4
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Minard AY, Clark CJ, Ahern CA, Piper RC. Beta-subunit-eliminated eHAP expression (BeHAPe) cells reveal subunit regulation of the cardiac voltage-gated sodium channel. J Biol Chem 2023; 299:105132. [PMID: 37544648 PMCID: PMC10506104 DOI: 10.1016/j.jbc.2023.105132] [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: 02/10/2023] [Revised: 07/27/2023] [Accepted: 07/31/2023] [Indexed: 08/08/2023] Open
Abstract
Voltage-gated sodium (NaV) channels drive the upstroke of the action potential and are comprised of a pore-forming α-subunit and regulatory β-subunits. The β-subunits modulate the gating, trafficking, and pharmacology of the α-subunit. These functions are routinely assessed by ectopic expression in heterologous cells. However, currently available expression systems may not capture the full range of these effects since they contain endogenous β-subunits. To better reveal β-subunit functions, we engineered a human cell line devoid of endogenous NaV β-subunits and their immediate phylogenetic relatives. This new cell line, β-subunit-eliminated eHAP expression (BeHAPe) cells, were derived from haploid eHAP cells by engineering inactivating mutations in the β-subunits SCN1B, SCN2B, SCN3B, and SCN4B, and other subfamily members MPZ (myelin protein zero(P0)), MPZL1, MPZL2, MPZL3, and JAML. In diploid BeHAPe cells, the cardiac NaV α-subunit, NaV1.5, was highly sensitive to β-subunit modulation and revealed that each β-subunit and even MPZ imparted unique gating properties. Furthermore, combining β1 and β2 with NaV1.5 generated a sodium channel with hybrid properties, distinct from the effects of the individual subunits. Thus, this approach revealed an expanded ability of β-subunits to regulate NaV1.5 activity and can be used to improve the characterization of other α/β NaV complexes.
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Affiliation(s)
- Annabel Y Minard
- Department of Molecular Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, Iowa, United States
| | - Colin J Clark
- Department of Molecular Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, Iowa, United States
| | - Christopher A Ahern
- Department of Molecular Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, Iowa, United States.
| | - Robert C Piper
- Department of Molecular Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, Iowa, United States.
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5
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Cruz FM, Macías Á, Moreno-Manuel AI, Gutiérrez LK, Vera-Pedrosa ML, Martínez-Carrascoso I, Pérez PS, Robles JMR, Bermúdez-Jiménez FJ, Díaz-Agustín A, de Benito FM, Santiago SA, Braza-Boils A, Martín-Martínez M, Gutierrez-Rodríguez M, Bernal JA, Zorio E, Jiménez-Jaimez J, Jalife J. Extracellular cysteine disulfide bond break at Cys122 disrupts PIP 2-dependent Kir2.1 channel function and leads to arrhythmias in Andersen-Tawil Syndrome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.07.544151. [PMID: 37333254 PMCID: PMC10274791 DOI: 10.1101/2023.06.07.544151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Background Andersen-Tawil Syndrome Type 1 (ATS1) is a rare heritable disease caused by mutations in the strong inwardly rectifying K+ channel Kir2.1. The extracellular Cys122-to-Cys154 disulfide bond in the Kir2.1 channel structure is crucial for proper folding, but has not been associated with correct channel function at the membrane. We tested whether a human mutation at the Cys122-to-Cys154 disulfide bridge leads to Kir2.1 channel dysfunction and arrhythmias by reorganizing the overall Kir2.1 channel structure and destabilizing the open state of the channel. Methods and Results We identified a Kir2.1 loss-of-function mutation in Cys122 (c.366 A>T; p.Cys122Tyr) in a family with ATS1. To study the consequences of this mutation on Kir2.1 function we generated a cardiac specific mouse model expressing the Kir2.1C122Y mutation. Kir2.1C122Y animals recapitulated the abnormal ECG features of ATS1, like QT prolongation, conduction defects, and increased arrhythmia susceptibility. Kir2.1C122Y mouse cardiomyocytes showed significantly reduced inward rectifier K+ (IK1) and inward Na+ (INa) current densities independently of normal trafficking ability and localization at the sarcolemma and the sarcoplasmic reticulum. Kir2.1C122Y formed heterotetramers with wildtype (WT) subunits. However, molecular dynamic modeling predicted that the Cys122-to-Cys154 disulfide-bond break induced by the C122Y mutation provoked a conformational change over the 2000 ns simulation, characterized by larger loss of the hydrogen bonds between Kir2.1 and phosphatidylinositol-4,5-bisphosphate (PIP2) than WT. Therefore, consistent with the inability of Kir2.1C122Y channels to bind directly to PIP2 in bioluminescence resonance energy transfer experiments, the PIP2 binding pocket was destabilized, resulting in a lower conductance state compared with WT. Accordingly, on inside-out patch-clamping the C122Y mutation significantly blunted Kir2.1 sensitivity to increasing PIP2 concentrations. Conclusion The extracellular Cys122-to-Cys154 disulfide bond in the tridimensional Kir2.1 channel structure is essential to channel function. We demonstrated that ATS1 mutations that break disulfide bonds in the extracellular domain disrupt PIP2-dependent regulation, leading to channel dysfunction and life-threatening arrhythmias.
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Affiliation(s)
- Francisco M. Cruz
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | - Álvaro Macías
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | | | - Lilian K. Gutiérrez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | | | | | | | | | - Francisco J Bermúdez-Jiménez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
- Servicio de Cardiología, Hospital Universitario Virgen de las Nieves, Granada, Spain
- Instituto de Investigación Biosanitaria de Granada IBS, Granada, Spain
| | - Aitor Díaz-Agustín
- Instituto de Química Médica (IQM), Consejo Superior de Investigaciones Científicas (CSIC), 28006 Madrid, Spain
| | - Fernando Martínez de Benito
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Salvador Arias Santiago
- Servicio de Dermatología Hospital Universitario Virgen de las Nieves
- Instituto de Investigación Biosanitaria de Granada IBS, Granada, Spain
| | - Aitana Braza-Boils
- Unit of Inherited Cardiomyopathies and Sudden Death (CAFAMUSME), Health Research Institute La Fe, La Fe Hospital, Valencia, Spain
- Cardiology Department, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Mercedes Martín-Martínez
- Instituto de Química Médica (IQM), Consejo Superior de Investigaciones Científicas (CSIC), 28006 Madrid, Spain
| | - Marta Gutierrez-Rodríguez
- Instituto de Química Médica (IQM), Consejo Superior de Investigaciones Científicas (CSIC), 28006 Madrid, Spain
| | - Juan A. Bernal
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Esther Zorio
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
- Unit of Inherited Cardiomyopathies and Sudden Death (CAFAMUSME), Health Research Institute La Fe, La Fe Hospital, Valencia, Spain
- Cardiology Department, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Juan Jiménez-Jaimez
- Servicio de Cardiología, Hospital Universitario Virgen de las Nieves, Granada, Spain
- Instituto de Investigación Biosanitaria de Granada IBS, Granada, Spain
| | - José Jalife
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
- Departments of Medicine and Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
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Angsutararux P, Dutta AK, Marras M, Abella C, Mellor RL, Shi J, Nerbonne JM, Silva JR. Differential regulation of cardiac sodium channels by intracellular fibroblast growth factors. J Gen Physiol 2023; 155:e202213300. [PMID: 36944081 PMCID: PMC10038838 DOI: 10.1085/jgp.202213300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 01/17/2023] [Accepted: 02/09/2023] [Indexed: 03/23/2023] Open
Abstract
Voltage-gated sodium (NaV) channels are responsible for the initiation and propagation of action potentials. In the heart, the predominant NaV1.5 α subunit is composed of four homologous repeats (I-IV) and forms a macromolecular complex with multiple accessory proteins, including intracellular fibroblast growth factors (iFGF). In spite of high homology, each of the iFGFs, iFGF11-iFGF14, as well as the individual iFGF splice variants, differentially regulates NaV channel gating, and the mechanisms underlying these differential effects remain elusive. Much of the work exploring iFGF regulation of NaV1.5 has been performed in mouse and rat ventricular myocytes in which iFGF13VY is the predominant iFGF expressed, whereas investigation into NaV1.5 regulation by the human heart-dominant iFGF12B is lacking. In this study, we used a mouse model with cardiac-specific Fgf13 deletion to study the consequences of iFGF13VY and iFGF12B expression. We observed distinct effects on the voltage-dependences of activation and inactivation of the sodium currents (INa), as well as on the kinetics of peak INa decay. Results in native myocytes were recapitulated with human NaV1.5 heterologously expressed in Xenopus oocytes, and additional experiments using voltage-clamp fluorometry (VCF) revealed iFGF-specific effects on the activation of the NaV1.5 voltage sensor domain in repeat IV (VSD-IV). iFGF chimeras further unveiled roles for all three iFGF domains (i.e., the N-terminus, core, and C-terminus) on the regulation of VSD-IV, and a slower time domain of inactivation. We present here a novel mechanism of iFGF regulation that is specific to individual iFGF isoforms and that leads to distinct functional effects on NaV channel/current kinetics.
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Affiliation(s)
- Paweorn Angsutararux
- Department of Biomedical Engineering, McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Amal K. Dutta
- Department of Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO, USA
| | - Martina Marras
- Department of Biomedical Engineering, McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Carlota Abella
- Department of Biomedical Engineering, McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Rebecca L. Mellor
- Department of Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO, USA
| | - Jingyi Shi
- Department of Biomedical Engineering, McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Jeanne M. Nerbonne
- Department of Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO, USA
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA
| | - Jonathan R. Silva
- Department of Biomedical Engineering, McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA
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7
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Hodges SL, Bouza AA, Isom LL. Therapeutic Potential of Targeting Regulated Intramembrane Proteolysis Mechanisms of Voltage-Gated Ion Channel Subunits and Cell Adhesion Molecules. Pharmacol Rev 2022; 74:1028-1048. [PMID: 36113879 PMCID: PMC9553118 DOI: 10.1124/pharmrev.121.000340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 05/13/2022] [Indexed: 10/03/2023] Open
Abstract
Several integral membrane proteins undergo regulated intramembrane proteolysis (RIP), a tightly controlled process through which cells transmit information across and between intracellular compartments. RIP generates biologically active peptides by a series of proteolytic cleavage events carried out by two primary groups of enzymes: sheddases and intramembrane-cleaving proteases (iCLiPs). Following RIP, fragments of both pore-forming and non-pore-forming ion channel subunits, as well as immunoglobulin super family (IgSF) members, have been shown to translocate to the nucleus to function in transcriptional regulation. As an example, the voltage-gated sodium channel β1 subunit, which is also an IgSF-cell adhesion molecule (CAM), is a substrate for RIP. β1 RIP results in generation of a soluble intracellular domain, which can regulate gene expression in the nucleus. In this review, we discuss the proposed RIP mechanisms of voltage-gated sodium, potassium, and calcium channel subunits as well as the roles of their generated proteolytic products in the nucleus. We also discuss other RIP substrates that are cleaved by similar sheddases and iCLiPs, such as IgSF macromolecules, including CAMs, whose proteolytically generated fragments function in the nucleus. Importantly, dysfunctional RIP mechanisms are linked to human disease. Thus, we will also review how understanding RIP events and subsequent signaling processes involving ion channel subunits and IgSF proteins may lead to the discovery of novel therapeutic targets. SIGNIFICANCE STATEMENT: Several ion channel subunits and immunoglobulin superfamily molecules have been identified as substrates of regulated intramembrane proteolysis (RIP). This signal transduction mechanism, which generates polypeptide fragments that translocate to the nucleus, is an important regulator of gene transcription. RIP may impact diseases of excitability, including epilepsy, cardiac arrhythmia, and sudden death syndromes. A thorough understanding of the role of RIP in gene regulation is critical as it may reveal novel therapeutic strategies for the treatment of previously intractable diseases.
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Affiliation(s)
- Samantha L Hodges
- Departments of Pharmacology (S.L.H., A.A.B., L.L.I.), Neurology (L.L.I.), and Molecular & Integrative Physiology (L.L.I.), University of Michigan Medical School, Ann Arbor, Michigan
| | - Alexandra A Bouza
- Departments of Pharmacology (S.L.H., A.A.B., L.L.I.), Neurology (L.L.I.), and Molecular & Integrative Physiology (L.L.I.), University of Michigan Medical School, Ann Arbor, Michigan
| | - Lori L Isom
- Departments of Pharmacology (S.L.H., A.A.B., L.L.I.), Neurology (L.L.I.), and Molecular & Integrative Physiology (L.L.I.), University of Michigan Medical School, Ann Arbor, Michigan
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8
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Manuel AIM, Gutiérrez LK, Pedrosa MLV, Uréndez FMC, Jiménez FJB, Carrascoso IM, Pérez PS, Macías Á, Jalife J. Molecular stratification of arrhythmogenic mechanisms in the Andersen Tawil Syndrome. Cardiovasc Res 2022; 119:919-932. [PMID: 35892314 PMCID: PMC10153646 DOI: 10.1093/cvr/cvac118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 06/20/2022] [Accepted: 07/01/2022] [Indexed: 11/12/2022] Open
Abstract
Andersen Tawil Syndrome (ATS) is a rare inheritable disease associated with loss-of-function mutations in KCNJ2, the gene coding the strong inward rectifier potassium channel Kir2.1, which forms an essential membrane protein controlling cardiac excitability. ATS is usually marked by a triad of periodic paralysis, life-threatening cardiac arrhythmias and dysmorphic features, but its expression is variable and not all patients with a phenotype linked to ATS have a known genetic alteration. The mechanisms underlying this arrhythmogenic syndrome are poorly understood. Knowing such mechanisms would be essential to distinguish ATS from other channelopathies with overlapping phenotypes and to develop individualized therapies. For example, the recently suggested role of Kir2.1 as a countercurrent to sarcoplasmic calcium reuptake might explain the arrhythmogenic mechanisms of ATS and its overlap with catecholaminergic polymorphic ventricular tachycardia (CPVT). Here we summarize current knowledge on the mechanisms of arrhythmias leading to sudden cardiac death in ATS. We first provide an overview of the syndrome and its pathophysiology, from the patient´s bedside to the protein, and discuss the role of essential regulators and interactors that could play a role in cases of ATS. The review highlights novel ideas related to some post-translational channel interactions with partner proteins that might help define the molecular bases of the arrhythmia phenotype. We then propose a new all-embracing classification of the currently known ATS loss-of-function mutations according to their position in the Kir2.1 channel structure and their functional implications. We also discuss specific ATS pathogenic variants, their clinical manifestations and treatment stratification. The goal is to provide a deeper mechanistic understanding of the syndrome toward the development of novel targets and personalized treatment strategies.
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Affiliation(s)
| | - Lilian K Gutiérrez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) Carlos III, 28029 Madrid, Spain
| | | | | | - Francisco José Bermúdez Jiménez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) Carlos III, 28029 Madrid, Spain.,Departamento de Cardiología, Hospital Virgen de las Nieves, GranadaSpain
| | | | - Patricia Sánchez Pérez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) Carlos III, 28029 Madrid, Spain
| | - Álvaro Macías
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) Carlos III, 28029 Madrid, Spain
| | - José Jalife
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) Carlos III, 28029 Madrid, Spain.,CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain.,Departments of Medicine and Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
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9
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Krahn AD, Behr ER, Hamilton R, Probst V, Laksman Z, Han HC. Brugada Syndrome. JACC Clin Electrophysiol 2022; 8:386-405. [PMID: 35331438 DOI: 10.1016/j.jacep.2021.12.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 12/09/2021] [Accepted: 12/15/2021] [Indexed: 12/15/2022]
Abstract
Brugada syndrome (BrS) is an "inherited" condition characterized by predisposition to syncope and cardiac arrest, predominantly during sleep. The prevalence is ∼1:2,000, and is more commonly diagnosed in young to middle-aged males, although patient sex does not appear to impact prognosis. Despite the perception of BrS being an inherited arrhythmia syndrome, most cases are not associated with a single causative gene variant. Electrocardiogram (ECG) findings support variable extent of depolarization and repolarization changes, with coved ST-segment elevation ≥2 mm and a negative T-wave in the right precordial leads. These ECG changes are often intermittent, and may be provoked by fever or sodium channel blocker challenge. Growing evidence from cardiac imaging, epicardial ablation, and pathology studies suggests the presence of an epicardial arrhythmic substrate within the right ventricular outflow tract. Risk stratification aims to identify those who are at increased risk of sudden cardiac death, with well-established factors being the presence of spontaneous ECG changes and a history of cardiac arrest or cardiogenic syncope. Current management involves conservative measures in asymptomatic patients, including fever management and drug avoidance. Symptomatic patients typically undergo implantable cardioverter defibrillator insertion, with quinidine and epicardial ablation used for patients with recurrent arrhythmia. This review summarizes our current understanding of BrS and provides clinicians with a practical approach to diagnosis and management.
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Affiliation(s)
- Andrew D Krahn
- Center for Cardiovascular Innovation, Heart Rhythm Services, Division of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada.
| | - Elijah R Behr
- Cardiovascular Clinical Academic Group and Cardiology Research Centre, St. George's, University of London and St. George's University Hospitals NHS Foundation Trust, London, United Kingdom
| | - Robert Hamilton
- Department of Pediatrics (Cardiology), The Labatt Family Heart Centre and Translational Medicine, The Hospital for Sick Children & Research Institute and the University of Toronto, Toronto, Canada
| | - Vincent Probst
- Cardiologic Department and Reference Center for Hereditary Arrhythmic Diseases, Nantes University Hospital, Nantes, France
| | - Zachary Laksman
- Center for Cardiovascular Innovation, Heart Rhythm Services, Division of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Hui-Chen Han
- Center for Cardiovascular Innovation, Heart Rhythm Services, Division of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada; Victorian Heart Institute, Monash University, Clayton, Victoria, Australia
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10
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Tikhonov DB, Zhorov BS. P-Loop Channels: Experimental Structures, and Physics-Based and Neural Networks-Based Models. MEMBRANES 2022; 12:membranes12020229. [PMID: 35207150 PMCID: PMC8876033 DOI: 10.3390/membranes12020229] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 02/09/2022] [Accepted: 02/09/2022] [Indexed: 01/27/2023]
Abstract
The superfamily of P-loop channels includes potassium, sodium, and calcium channels, as well as TRP channels and ionotropic glutamate receptors. A rapidly increasing number of crystal and cryo-EM structures have revealed conserved and variable elements of the channel structures. Intriguing differences are seen in transmembrane helices of channels, which may include π-helical bulges. The bulges reorient residues in the helices and thus strongly affect their intersegment contacts and patterns of ligand-sensing residues. Comparison of the experimental structures suggests that some π-bulges are dynamic: they may appear and disappear upon channel gating and ligand binding. The AlphaFold2 models represent a recent breakthrough in the computational prediction of protein structures. We compared some crystal and cryo-EM structures of P-loop channels with respective AlphaFold2 models. Folding of the regions, which are resolved experimentally, is generally similar to that predicted in the AlphaFold2 models. The models also reproduce some subtle but significant differences between various P-loop channels. However, patterns of π-bulges do not necessarily coincide in the experimental and AlphaFold2 structures. Given the importance of dynamic π-bulges, further studies involving experimental and theoretical approaches are necessary to understand the cause of the discrepancy.
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11
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Membrane excitability: Ankyrins keep neuromuscular junctions firing. Curr Biol 2021; 31:R1061-R1063. [PMID: 34520721 DOI: 10.1016/j.cub.2021.07.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Voltage-gated sodium channels are clustered and immobilized at high densities in electrically excitable cells. A new study shows that ankyrins are essential to tether sodium channels and prevent synaptic fatigue at the neuromuscular junction.
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12
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Ademuwagun IA, Rotimi SO, Syrbe S, Ajamma YU, Adebiyi E. Voltage Gated Sodium Channel Genes in Epilepsy: Mutations, Functional Studies, and Treatment Dimensions. Front Neurol 2021; 12:600050. [PMID: 33841294 PMCID: PMC8024648 DOI: 10.3389/fneur.2021.600050] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 03/01/2021] [Indexed: 12/19/2022] Open
Abstract
Genetic epilepsy occurs as a result of mutations in either a single gene or an interplay of different genes. These mutations have been detected in ion channel and non-ion channel genes. A noteworthy class of ion channel genes are the voltage gated sodium channels (VGSCs) that play key roles in the depolarization phase of action potentials in neurons. Of huge significance are SCN1A, SCN1B, SCN2A, SCN3A, and SCN8A genes that are highly expressed in the brain. Genomic studies have revealed inherited and de novo mutations in sodium channels that are linked to different forms of epilepsies. Due to the high frequency of sodium channel mutations in epilepsy, this review discusses the pathogenic mutations in the sodium channel genes that lead to epilepsy. In addition, it explores the functional studies on some known mutations and the clinical significance of VGSC mutations in the medical management of epilepsy. The understanding of these channel mutations may serve as a strong guide in making effective treatment decisions in patient management.
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Affiliation(s)
- Ibitayo Abigail Ademuwagun
- Covenant University Bioinformatics Research, Covenant University, Ota, Nigeria
- Department of Biochemistry, Covenant University, Ota, Nigeria
| | - Solomon Oladapo Rotimi
- Covenant University Bioinformatics Research, Covenant University, Ota, Nigeria
- Department of Biochemistry, Covenant University, Ota, Nigeria
| | - Steffen Syrbe
- Clinic for Pediatric and Adolescent Medicine, Heidelberg University, Heidelberg, Germany
| | | | - Ezekiel Adebiyi
- Covenant University Bioinformatics Research, Covenant University, Ota, Nigeria
- Department of Computer and Information Sciences, Covenant University, Ota, Nigeria
- Division of Applied Bioinformatics, German Cancer Research Center (DKFZ), Heidelberg, Germany
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13
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Zhang XD, Thai PN, Lieu DK, Chiamvimonvat N. Cardiac small-conductance calcium-activated potassium channels in health and disease. Pflugers Arch 2021; 473:477-489. [PMID: 33624131 PMCID: PMC7940285 DOI: 10.1007/s00424-021-02535-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 12/22/2022]
Abstract
Small-conductance Ca2+-activated K+ (SK, KCa2) channels are encoded by KCNN genes, including KCNN1, 2, and 3. The channels play critical roles in the regulation of cardiac excitability and are gated solely by beat-to-beat changes in intracellular Ca2+. The family of SK channels consists of three members with differential sensitivity to apamin. All three isoforms are expressed in human hearts. Studies over the past two decades have provided evidence to substantiate the pivotal roles of SK channels, not only in healthy heart but also with diseases including atrial fibrillation (AF), ventricular arrhythmia, and heart failure (HF). SK channels are prominently expressed in atrial myocytes and pacemaking cells, compared to ventricular cells. However, the channels are significantly upregulated in ventricular myocytes in HF and pulmonary veins in AF models. Interests in cardiac SK channels are further fueled by recent studies suggesting the possible roles of SK channels in human AF. Therefore, SK channel may represent a novel therapeutic target for atrial arrhythmias. Furthermore, SK channel function is significantly altered by human calmodulin (CaM) mutations, linked to life-threatening arrhythmia syndromes. The current review will summarize recent progress in our understanding of cardiac SK channels and the roles of SK channels in the heart in health and disease.
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Affiliation(s)
- Xiao-Dong Zhang
- Division of Cardiovascular Medicine, Department of Internal Medicine, School of Medicine, University of California, Davis, One Shields Avenue, GBSF 6315, Davis, CA, 95616, USA.
- Department of Veterans Affairs, Northern California Health Care System, 10535 Hospital Way, Mather, CA, 95655, USA.
| | - Phung N Thai
- Division of Cardiovascular Medicine, Department of Internal Medicine, School of Medicine, University of California, Davis, One Shields Avenue, GBSF 6315, Davis, CA, 95616, USA
- Department of Veterans Affairs, Northern California Health Care System, 10535 Hospital Way, Mather, CA, 95655, USA
| | - Deborah K Lieu
- Division of Cardiovascular Medicine, Department of Internal Medicine, School of Medicine, University of California, Davis, One Shields Avenue, GBSF 6315, Davis, CA, 95616, USA
| | - Nipavan Chiamvimonvat
- Division of Cardiovascular Medicine, Department of Internal Medicine, School of Medicine, University of California, Davis, One Shields Avenue, GBSF 6315, Davis, CA, 95616, USA.
- Department of Veterans Affairs, Northern California Health Care System, 10535 Hospital Way, Mather, CA, 95655, USA.
- Department of Pharmacology, School of Medicine, University of California, Davis, Davis, CA, 95616, USA.
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14
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Salvage SC, Huang CLH, Jackson AP. Cell-Adhesion Properties of β-Subunits in the Regulation of Cardiomyocyte Sodium Channels. Biomolecules 2020; 10:biom10070989. [PMID: 32630316 PMCID: PMC7407995 DOI: 10.3390/biom10070989] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 06/25/2020] [Accepted: 06/27/2020] [Indexed: 12/17/2022] Open
Abstract
Voltage-gated sodium (Nav) channels drive the rising phase of the action potential, essential for electrical signalling in nerves and muscles. The Nav channel α-subunit contains the ion-selective pore. In the cardiomyocyte, Nav1.5 is the main Nav channel α-subunit isoform, with a smaller expression of neuronal Nav channels. Four distinct regulatory β-subunits (β1–4) bind to the Nav channel α-subunits. Previous work has emphasised the β-subunits as direct Nav channel gating modulators. However, there is now increasing appreciation of additional roles played by these subunits. In this review, we focus on β-subunits as homophilic and heterophilic cell-adhesion molecules and the implications for cardiomyocyte function. Based on recent cryogenic electron microscopy (cryo-EM) data, we suggest that the β-subunits interact with Nav1.5 in a different way from their binding to other Nav channel isoforms. We believe this feature may facilitate trans-cell-adhesion between β1-associated Nav1.5 subunits on the intercalated disc and promote ephaptic conduction between cardiomyocytes.
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Affiliation(s)
- Samantha C. Salvage
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK;
- Correspondence: (S.C.S.); (A.P.J.); Tel.: +44-1223-765950 (S.C.S.); +44-1223-765951 (A.P.J.)
| | - Christopher L.-H. Huang
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK;
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
| | - Antony P. Jackson
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK;
- Correspondence: (S.C.S.); (A.P.J.); Tel.: +44-1223-765950 (S.C.S.); +44-1223-765951 (A.P.J.)
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15
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Smirnov D, Pikunov A, Syunyaev R, Deviatiiarov R, Gusev O, Aras K, Gams A, Koppel A, Efimov IR. Genetic algorithm-based personalized models of human cardiac action potential. PLoS One 2020; 15:e0231695. [PMID: 32392258 PMCID: PMC7213718 DOI: 10.1371/journal.pone.0231695] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 03/31/2020] [Indexed: 11/21/2022] Open
Abstract
We present a novel modification of genetic algorithm (GA) which determines personalized parameters of cardiomyocyte electrophysiology model based on set of experimental human action potential (AP) recorded at different heart rates. In order to find the steady state solution, the optimized algorithm performs simultaneous search in the parametric and slow variables spaces. We demonstrate that several GA modifications are required for effective convergence. Firstly, we used Cauchy mutation along a random direction in the parametric space. Secondly, relatively large number of elite organisms (6-10% of the population passed on to new generation) was required for effective convergence. Test runs with synthetic AP as input data indicate that algorithm error is low for high amplitude ionic currents (1.6±1.6% for IKr, 3.2±3.5% for IK1, 3.9±3.5% for INa, 8.2±6.3% for ICaL). Experimental signal-to-noise ratio above 28 dB was required for high quality GA performance. GA was validated against optical mapping recordings of human ventricular AP and mRNA expression profile of donor hearts. In particular, GA output parameters were rescaled proportionally to mRNA levels ratio between patients. We have demonstrated that mRNA-based models predict the AP waveform dependence on heart rate with high precision. The latter also provides a novel technique of model personalization that makes it possible to map gene expression profile to cardiac function.
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Affiliation(s)
- Dmitrii Smirnov
- Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Andrey Pikunov
- Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Roman Syunyaev
- Moscow Institute of Physics and Technology, Dolgoprudny, Russia
- The George Washington University, Washington, DC, United States of America
- Sechenov University, Moscow, Russia
| | | | | | - Kedar Aras
- The George Washington University, Washington, DC, United States of America
| | - Anna Gams
- The George Washington University, Washington, DC, United States of America
| | - Aaron Koppel
- The George Washington University, Washington, DC, United States of America
| | - Igor R. Efimov
- Moscow Institute of Physics and Technology, Dolgoprudny, Russia
- The George Washington University, Washington, DC, United States of America
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16
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Wang L, Han Z, Dai J, Cao K. Brugada Syndrome Caused by Sodium Channel Dysfunction Associated with a SCN1B Variant A197V. Arch Med Res 2020; 51:245-253. [PMID: 32192759 DOI: 10.1016/j.arcmed.2020.02.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 01/18/2020] [Accepted: 02/10/2020] [Indexed: 12/14/2022]
Abstract
OBJECTIVE We aimed to identify and characterize a SCN1B variant, A197V, associated with Brugada Syndrome (BrS). METHODS Whole-exome sequencing was employed to explore the potential causative genes in 8 unrelated clinically diagnosed BrS patients. A197V variant was only detected in exon 4 of SCN1B in a 46 year old patient, who was admitted due to syncope. Wild type (WT) and mutant (A197V) genes were co-expressed with SCN5A in human embryonic kidney cells (HEK293 cells) and studied using whole-cell patch clamp and immunodetection techniques. RESULTS Coexpression of 5A/WT + 1B/A197V resulted in a marked decrease in current density compared to 5A/WT + 1B/WT. The activation velocity was decelerated by A197V mutation. No significant changes were observed in recovery from inactivation parameters. Cell surface protein analyses confirmed that Nav1.5 channel membrane distribution was affected by A197V mutation. CONCLUSIONS The current study is the first to report the functional analysis of SCN1B/ A197V, serving as a substrate responsible for BrS.
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Affiliation(s)
- Linlin Wang
- Department of Cardiology, Nanjing Brain Hospital, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing, People's Republic of China
| | - Zhonglin Han
- Department of Cardiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, People's Republic of China
| | - Jian Dai
- Department of Cardiology, Nanjing Brain Hospital, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing, People's Republic of China
| | - Kejiang Cao
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, People's Republic of China.
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17
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Clinical characterisation of a novel SCN5A variant associated with progressive malignant arrhythmia and dilated cardiomyopathy. Cardiol Young 2019; 29:1257-1263. [PMID: 31477192 DOI: 10.1017/s1047951119001860] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
INTRODUCTION The SCN5A gene is implicated in many arrhythmogenic and cardiomyopathic processes. We identified a novel SCN5A variant in a family with significant segregation in individuals affected with progressive sinus and atrioventricular nodal disease, atrial arrhythmia, dilated cardiomyopathy, and early sudden cardiac arrest. METHODS A patient pedigree was created following the clinical evaluation of three affected individuals, two monozygotic twins and a paternal half-brother, which lead to the evaluation of a paternal half-sister (four siblings with the same father and three mothers) all of whom experienced varying degrees of atrial arrhythmias, conduction disease, and dilated cardiomyopathy in addition to a paternal history of unexplained death in his 50s with similar autopsy findings. The index male underwent sequencing of 58 genes associated with cardiomyopathies. Sanger sequencing was used to provide data for bases with insufficient coverage and for bases in some known regions of genomic segmental duplications. All clinically significant and novel variants were confirmed by independent Sanger sequencing. RESULTS All relatives tested were shown to have the same SCN5A variant of unknown significance (p. Asp197His) and the monozygotic twins shared a co-occurring NEXN (p. Glu575*). Segregation analysis demonstrates likely pathogenic trait for the SCN5A variant with an additional possible role for the NEXN variant in combination. CONCLUSIONS There is compelling clinical evidence suggesting that the SCN5A variant p. Asp197His may be re-classified as likely pathogenic based on the segregation analysis of our family of interest. Molecular mechanism studies are pending.
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18
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Bedoya M, Rinné S, Kiper AK, Decher N, González W, Ramírez D. TASK Channels Pharmacology: New Challenges in Drug Design. J Med Chem 2019; 62:10044-10058. [PMID: 31260312 DOI: 10.1021/acs.jmedchem.9b00248] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Rational drug design targeting ion channels is an exciting and always evolving research field. New medicinal chemistry strategies are being implemented to explore the wild chemical space and unravel the molecular basis of the ion channels modulators binding mechanisms. TASK channels belong to the two-pore domain potassium channel family and are modulated by extracellular acidosis. They are extensively distributed along the cardiovascular and central nervous systems, and their expression is up- and downregulated in different cancer types, which makes them an attractive therapeutic target. However, TASK channels remain unexplored, and drugs designed to target these channels are poorly selective. Here, we review TASK channels properties and their known blockers and activators, considering the new challenges in ion channels drug design and focusing on the implementation of computational methodologies in the drug discovery process.
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Affiliation(s)
- Mauricio Bedoya
- Centro de Bioinformática y Simulación Molecular (CBSM) , Universidad de Talca , 1 Poniente No. 1141 , 3460000 Talca , Chile
| | - Susanne Rinné
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior, MCMBB , Philipps-University of Marburg , Deutschhausstraße 2 , Marburg 35037 , Germany
| | - Aytug K Kiper
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior, MCMBB , Philipps-University of Marburg , Deutschhausstraße 2 , Marburg 35037 , Germany
| | - Niels Decher
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior, MCMBB , Philipps-University of Marburg , Deutschhausstraße 2 , Marburg 35037 , Germany
| | - Wendy González
- Centro de Bioinformática y Simulación Molecular (CBSM) , Universidad de Talca , 1 Poniente No. 1141 , 3460000 Talca , Chile.,Millennium Nucleus of Ion Channels-Associated Diseases (MiNICAD) , Universidad de Talca , 1 Poniente No. 1141 , 3460000 Talca , Chile
| | - David Ramírez
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud , Universidad Autónoma de Chile , El Llano Subercaseaux 2801, Piso 6 , 8900000 Santiago , Chile
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19
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Chu L, Greenstein JL, Winslow RL. Na + microdomains and sparks: Role in cardiac excitation-contraction coupling and arrhythmias in ankyrin-B deficiency. J Mol Cell Cardiol 2019; 128:145-157. [PMID: 30731085 DOI: 10.1016/j.yjmcc.2019.02.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 02/01/2019] [Accepted: 02/02/2019] [Indexed: 01/25/2023]
Abstract
Cardiac sodium (Na+) potassium ATPase (NaK) pumps, neuronal sodium channels (INa), and sodium calcium (Ca2+) exchangers (NCX1) may co-localize to form a Na+ microdomain. It remains controversial as to whether neuronal INa contributes to local Na+ accumulation, resulting in reversal of nearby NCX1 and influx of Ca2+ into the cell. Therefore, there has been great interest in the possible roles of a Na+ microdomain in cardiac Ca2+-induced Ca2+ release (CICR). In addition, the important role of co-localization of NaK and NCX1 in regulating localized Na+ and Ca2+ levels and CICR in ankyrin-B deficient (ankyrin-B+/-) cardiomyocytes has been examined in many recent studies. Altered Na+ dynamics may contribute to the appearance of arrhythmias, but the mechanisms underlying this relationship remain unclear. In order to investigate this, we present a mechanistic canine cardiomyocyte model which reproduces independent local dyadic junctional SR (JSR) Ca2+ release events underlying cell-wide excitation-contraction coupling, as well as a three-dimensional super-resolution model of the Ca2+ spark that describes local Na+ dynamics as governed by NaK pumps, neuronal INa, and NCX1. The model predicts the existence of Na+ sparks, which are generated by NCX1 and exhibit significantly slower dynamics as compared to Ca2+ sparks. Moreover, whole-cell simulations indicate that neuronal INa in the cardiac dyad plays a key role during the systolic phase. Rapid inward neuronal INa can elevate dyadic [Na+] to 35-40 mM, which drives reverse-mode NCX1 transport, and therefore promotes Ca2+ entry into the dyad, enhancing the trigger for JSR Ca2+ release. The specific role of decreased co-localization of NaK and NCX1 in ankyrin-B+/- cardiomyocytes was examined. Model results demonstrate that a reduction in the local NCX1- and NaK-mediated regulation of dyadic [Ca2+] and [Na+] results in an increase in Ca2+ spark activity during isoproterenol stimulation, which in turn stochastically activates NCX1 in the dyad. This alteration in NCX1/NaK co-localization interrupts the balance between NCX1 and NaK currents in a way that leads to enhanced depolarizing inward current during the action potential plateau, which ultimately leads to a higher probability of L-type Ca2+ channel reopening and arrhythmogenic early-afterdepolarizations.
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Affiliation(s)
- Lulu Chu
- Department of Biomedical Engineering and the Institute for Computational Medicine, The Johns Hopkins University School of Medicine and Whiting School of Engineering, 3400 N Charles Street, Baltimore, MD 21218, USA.
| | - Joseph L Greenstein
- Department of Biomedical Engineering and the Institute for Computational Medicine, The Johns Hopkins University School of Medicine and Whiting School of Engineering, 3400 N Charles Street, Baltimore, MD 21218, USA.
| | - Raimond L Winslow
- Department of Biomedical Engineering and the Institute for Computational Medicine, The Johns Hopkins University School of Medicine and Whiting School of Engineering, 3400 N Charles Street, Baltimore, MD 21218, USA.
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20
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Ravens U. Ionic basis of cardiac electrophysiology in zebrafish compared to human hearts. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2018; 138:38-44. [DOI: 10.1016/j.pbiomolbio.2018.06.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 05/23/2018] [Accepted: 06/15/2018] [Indexed: 12/14/2022]
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21
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Ransdell JL, Nerbonne JM. Voltage-gated sodium currents in cerebellar Purkinje neurons: functional and molecular diversity. Cell Mol Life Sci 2018; 75:3495-3505. [PMID: 29982847 PMCID: PMC6123253 DOI: 10.1007/s00018-018-2868-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 06/28/2018] [Accepted: 07/03/2018] [Indexed: 01/09/2023]
Abstract
Purkinje neurons, the sole output of the cerebellar cortex, deliver GABA-mediated inhibition to the deep cerebellar nuclei. To subserve this critical function, Purkinje neurons fire repetitively, and at high frequencies, features that have been linked to the unique properties of the voltage-gated sodium (Nav) channels expressed. In addition to the rapidly activating and inactivating, or transient, component of the Nav current (INaT) present in many types of central and peripheral neurons, Purkinje neurons, also expresses persistent (INaP) and resurgent (INaR) Nav currents. Considerable progress has been made in detailing the biophysical properties and identifying the molecular determinants of these discrete Nav current components, as well as defining their roles in the regulation of Purkinje neuron excitability. Here, we review this important work and highlight the remaining questions about the molecular mechanisms controlling the expression and the functioning of Nav currents in Purkinje neurons. We also discuss the impact of the dynamic regulation of Nav currents on the functioning of individual Purkinje neurons and cerebellar circuits.
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Affiliation(s)
- Joseph L Ransdell
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Medicine, Washington University School of Medicine, Box 8086, 660 South Euclid Avenue, St. Louis, MO, 63110, USA
| | - Jeanne M Nerbonne
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA.
- Department of Medicine, Washington University School of Medicine, Box 8086, 660 South Euclid Avenue, St. Louis, MO, 63110, USA.
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22
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Yao H, Fan J, Cheng YJ, Chen XM, Ji CC, Liu LJ, Zheng ZH, Wu SH. SCN1Bβ mutations that affect their association with Kv4.3 underlie early repolarization syndrome. J Cell Mol Med 2018; 22:5639-5647. [PMID: 30160358 PMCID: PMC6201368 DOI: 10.1111/jcmm.13839] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 07/13/2018] [Indexed: 12/12/2022] Open
Abstract
Background Abnormal cardiac ion channels current, including transient outward potassium current (Ito), is associated with early repolarization syndrome (ERS). Previous studies showed that mutations in SCN1Bβ both to increase the Ito current and to decrease the sodium current. Yet its role in ERS remains unknown. Objective To determine the role of mutations in the SCN1Bβ subunits in ERS. Methods We screened for mutations in the SCN1B genes from four families with ERS. Wild‐type and mutant SCN1Bβ genes were co‐expressed with wild‐type KCND3 in human embryonic kidney cells (HEK293). Whole‐cell patch‐clamp technique and co‐immunoprecipitation were used to study the electrophysiological properties and explore the underlying mechanisms. Results S248R and R250T mutations in SCN1Bβ were detected in 4 families’ probands. Neither S248R nor R250T mutation had significant influence on the sodium channel current density (INa) when co‐expressed with SCN5A/WT. Co‐expression of KCND3/WT and SCN1Bβ/S248R or SCN1Bβ/R250T increased the transient outward potassium current Ito by 27.44% and 199.89%, respectively (P < 0.05 and P < 0.01, respectively) when compared with SCN1Bβ/WT. Electrophysiological properties showed that S248R and R250T mutations decreased the steady‐state inactivation and recovery from inactivation of Ito channel. Co‐immunoprecipitation study demonstrated an increased association between SCN1Bβ mutations and Kv4.3 compared with SCN1Bβ/WT (P < 0.05 and P < 0.01, respectively). Conclusion The S248R and R250T mutations of SCN1Bβ gene caused gain‐of‐function of Ito by associated with Kv4.3, which maybe underlie the ERS phenotype of the probands.
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Affiliation(s)
- Hao Yao
- Department of Cardiology, the First Affiliated Hospital, Sun Yat-Sen University, and Key Laboratory on Assisted Circulation, NHC, Guangzhou, China
| | - Jun Fan
- Department of Cardiology, the First Affiliated Hospital, Sun Yat-Sen University, and Key Laboratory on Assisted Circulation, NHC, Guangzhou, China
| | - Yun-Jiu Cheng
- Department of Cardiology, the First Affiliated Hospital, Sun Yat-Sen University, and Key Laboratory on Assisted Circulation, NHC, Guangzhou, China
| | - Xu-Miao Chen
- Department of Cardiology, the First Affiliated Hospital, Sun Yat-Sen University, and Key Laboratory on Assisted Circulation, NHC, Guangzhou, China
| | - Cheng-Cheng Ji
- Department of Cardiology, the First Affiliated Hospital, Sun Yat-Sen University, and Key Laboratory on Assisted Circulation, NHC, Guangzhou, China
| | - Li-Juan Liu
- Department of Cardiology, the First Affiliated Hospital, Sun Yat-Sen University, and Key Laboratory on Assisted Circulation, NHC, Guangzhou, China
| | - Zi-Heng Zheng
- Department of Cardiology, the First Affiliated Hospital, Sun Yat-Sen University, and Key Laboratory on Assisted Circulation, NHC, Guangzhou, China
| | - Su-Hua Wu
- Department of Cardiology, the First Affiliated Hospital, Sun Yat-Sen University, and Key Laboratory on Assisted Circulation, NHC, Guangzhou, China
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23
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Godazgar M, Zhang Q, Chibalina MV, Rorsman P. Biphasic voltage-dependent inactivation of human Na V 1.3, 1.6 and 1.7 Na + channels expressed in rodent insulin-secreting cells. J Physiol 2018; 596:1601-1626. [PMID: 29441586 PMCID: PMC5924821 DOI: 10.1113/jp275587] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 02/06/2018] [Indexed: 12/12/2022] Open
Abstract
KEY POINTS Na+ current inactivation is biphasic in insulin-secreting cells, proceeding with two voltage dependences that are half-maximal at ∼-100 mV and -60 mV. Inactivation of voltage-gated Na+ (NaV ) channels occurs at ∼30 mV more negative voltages in insulin-secreting Ins1 and primary β-cells than in HEK, CHO or glucagon-secreting αTC1-6 cells. The difference in inactivation between Ins1 and non-β-cells persists in the inside-out patch configuration, discounting an involvement of a diffusible factor. In Ins1 cells and primary β-cells, but not in HEK cells, inactivation of a single NaV subtype is biphasic and follows two voltage dependences separated by 30-40 mV. We propose that NaV channels adopt different inactivation behaviours depending on the local membrane environment. ABSTRACT Pancreatic β-cells are equipped with voltage-gated Na+ channels that undergo biphasic voltage-dependent steady-state inactivation. A small Na+ current component (10-15%) inactivates over physiological membrane potentials and contributes to action potential firing. However, the major Na+ channel component is completely inactivated at -90 to -80 mV and is therefore inactive in the β-cell. It has been proposed that the biphasic inactivation reflects the contribution of different NaV α-subunits. We tested this possibility by expression of TTX-resistant variants of the NaV subunits found in β-cells (NaV 1.3, NaV 1.6 and NaV 1.7) in insulin-secreting Ins1 cells and in non-β-cells (including HEK and CHO cells). We found that all NaV subunits inactivated at 20-30 mV more negative membrane potentials in Ins1 cells than in HEK or CHO cells. The more negative inactivation in Ins1 cells does not involve a diffusible intracellular factor because the difference between Ins1 and CHO persisted after excision of the membrane. NaV 1.7 inactivated at 15--20 mV more negative membrane potentials than NaV 1.3 and NaV 1.6 in Ins1 cells but this small difference is insufficient to solely explain the biphasic inactivation in Ins1 cells. In Ins1 cells, but never in the other cell types, widely different components of NaV inactivation (separated by 30 mV) were also observed following expression of a single type of NaV α-subunit. The more positive component exhibited a voltage dependence of inactivation similar to that found in HEK and CHO cells. We propose that biphasic NaV inactivation in insulin-secreting cells reflects insertion of channels in membrane domains that differ with regard to lipid and/or membrane protein composition.
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Affiliation(s)
- Mahdieh Godazgar
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of MedicineUniversity of OxfordChurchill HospitalOxfordOX3 7LEUK
| | - Quan Zhang
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of MedicineUniversity of OxfordChurchill HospitalOxfordOX3 7LEUK
| | - Margarita V. Chibalina
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of MedicineUniversity of OxfordChurchill HospitalOxfordOX3 7LEUK
| | - Patrik Rorsman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of MedicineUniversity of OxfordChurchill HospitalOxfordOX3 7LEUK
- Metabolic PhysiologyDepartment of Neuroscience and PhysiologyMedicinaregatan 11GothenburgS‐413 09Sweden
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24
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El-Battrawy I, Zhao Z, Lan H, Li X, Yücel G, Lang S, Sattler K, Schünemann JD, Zimmermann WH, Cyganek L, Utikal J, Wieland T, Bieback K, Bauer R, Ratte A, Pribe-Wolferts R, Rapti K, Nowak D, Wittig J, Thomas D, Most P, Katus HA, Ravens U, Schmidt C, Borggrefe M, Zhou XB, Müller OJ, Akin I. Ion Channel Dysfunctions in Dilated Cardiomyopathy in Limb-Girdle Muscular Dystrophy. CIRCULATION-GENOMIC AND PRECISION MEDICINE 2018; 11:e001893. [DOI: 10.1161/circgen.117.001893] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Accepted: 01/10/2018] [Indexed: 12/16/2022]
Affiliation(s)
- Ibrahim El-Battrawy
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Zhihan Zhao
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Huan Lan
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Xin Li
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Gökhan Yücel
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Siegfried Lang
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Katherine Sattler
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Jan-Dierk Schünemann
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Wolfram-Hubertus Zimmermann
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Lukas Cyganek
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Jochen Utikal
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Thomas Wieland
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Karen Bieback
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Ralf Bauer
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Antonius Ratte
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Regina Pribe-Wolferts
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Kleopatra Rapti
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Daniel Nowak
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Janina Wittig
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Dierk Thomas
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Patrick Most
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Hugo A. Katus
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Ursula Ravens
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Constanze Schmidt
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Martin Borggrefe
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Xiao-Bo Zhou
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Oliver J. Müller
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
| | - Ibrahim Akin
- From the First Department of Medicine, Faculty of Medicine (I.E.-B., Z.Z., H.L., X.L., G.Y., S.L., K.S., J.-D.S., M.B., X.-B.Z., I.A.) and Department of Dermatology, Venereology and Allergology (J.U.), University Medical Centre Mannheim, University of Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Sites, Heidelberg-Mannheim and Göttingen (I.E.-B., Z.Z., H.L., G.Y., S.L., W.-H.Z., L.C., J.U., T.W., R.B., A.R., D.T., P.M., H.A.K., C.S., M.B., X.-B.Z., O.J.M., I.A.)
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Kanellopoulos AH, Koenig J, Huang H, Pyrski M, Millet Q, Lolignier S, Morohashi T, Gossage SJ, Jay M, Linley JE, Baskozos G, Kessler BM, Cox JJ, Dolphin AC, Zufall F, Wood JN, Zhao J. Mapping protein interactions of sodium channel Na V1.7 using epitope-tagged gene-targeted mice. EMBO J 2018; 37:427-445. [PMID: 29335280 PMCID: PMC5793798 DOI: 10.15252/embj.201796692] [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] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 11/30/2017] [Accepted: 12/05/2017] [Indexed: 11/24/2022] Open
Abstract
The voltage-gated sodium channel NaV1.7 plays a critical role in pain pathways. We generated an epitope-tagged NaV1.7 mouse that showed normal pain behaviours to identify channel-interacting proteins. Analysis of NaV1.7 complexes affinity-purified under native conditions by mass spectrometry revealed 267 proteins associated with Nav1.7 in vivo The sodium channel β3 (Scn3b), rather than the β1 subunit, complexes with Nav1.7, and we demonstrate an interaction between collapsing-response mediator protein (Crmp2) and Nav1.7, through which the analgesic drug lacosamide regulates Nav1.7 current density. Novel NaV1.7 protein interactors including membrane-trafficking protein synaptotagmin-2 (Syt2), L-type amino acid transporter 1 (Lat1) and transmembrane P24-trafficking protein 10 (Tmed10) together with Scn3b and Crmp2 were validated by co-immunoprecipitation (Co-IP) from sensory neuron extract. Nav1.7, known to regulate opioid receptor efficacy, interacts with the G protein-regulated inducer of neurite outgrowth (Gprin1), an opioid receptor-binding protein, demonstrating a physical and functional link between Nav1.7 and opioid signalling. Further information on physiological interactions provided with this normal epitope-tagged mouse should provide useful insights into the many functions now associated with the NaV1.7 channel.
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Affiliation(s)
| | - Jennifer Koenig
- Molecular Nociception Group, WIBR, University College London, London, UK
| | - Honglei Huang
- TDI Mass Spectrometry Laboratory, Target Discovery Institute, University of Oxford, Oxford, UK
| | - Martina Pyrski
- Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Queensta Millet
- Molecular Nociception Group, WIBR, University College London, London, UK
| | - Stéphane Lolignier
- Molecular Nociception Group, WIBR, University College London, London, UK
- Université Clermont Auvergne, Inserm U1107 Neuro-Dol, Pharmacologie Fondamentale et Clinique de la Douleur, Clermont-Ferrand, France
| | - Toru Morohashi
- Molecular Nociception Group, WIBR, University College London, London, UK
| | - Samuel J Gossage
- Molecular Nociception Group, WIBR, University College London, London, UK
| | - Maude Jay
- Molecular Nociception Group, WIBR, University College London, London, UK
| | - John E Linley
- Molecular Nociception Group, WIBR, University College London, London, UK
- Neuroscience, IMED Biotech Unit, AstraZeneca, Cambridge, UK
| | | | - Benedikt M Kessler
- TDI Mass Spectrometry Laboratory, Target Discovery Institute, University of Oxford, Oxford, UK
| | - James J Cox
- Molecular Nociception Group, WIBR, University College London, London, UK
| | - Annette C Dolphin
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Frank Zufall
- Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - John N Wood
- Molecular Nociception Group, WIBR, University College London, London, UK
| | - Jing Zhao
- Molecular Nociception Group, WIBR, University College London, London, UK
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Peters CH, Ghovanloo MR, Gershome C, Ruben PC. pH Modulation of Voltage-Gated Sodium Channels. Handb Exp Pharmacol 2018; 246:147-160. [PMID: 29460150 DOI: 10.1007/164_2018_99] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Changes in blood and tissue pH accompany physiological and pathophysiological conditions including exercise, cardiac ischemia, ischemic stroke, and cocaine ingestion. These conditions are known to trigger the symptoms of electrical diseases in patients carrying sodium channel mutations. Protons cause a diverse set of changes to sodium channel gating, which generally lead to decreases in the amplitude of the transient sodium current and increases in the fraction of non-inactivating channels that pass persistent currents. These effects are shared with disease-causing mutants in neuronal, skeletal muscle, and cardiac tissue and may be compounded in mutants that impart greater proton sensitivity to sodium channels, suggesting a role of protons in triggering acute symptoms of electrical disease.In this chapter, we review the mechanisms of proton block of the sodium channel pore and a suggested mode of action by which protons alter channel gating. We discuss the available data on isoform specificity of proton effects and tissue level effects. Finally, we review the role that protons play in disease and our own recent studies on proton-sensitizing mutants in cardiac and skeletal muscle sodium channels.
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Affiliation(s)
- Colin H Peters
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Mohammad-Reza Ghovanloo
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Cynthia Gershome
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Peter C Ruben
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada.
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Savio-Galimberti E, Argenziano M, Antzelevitch C. Cardiac Arrhythmias Related to Sodium Channel Dysfunction. Handb Exp Pharmacol 2018; 246:331-354. [PMID: 28965168 DOI: 10.1007/164_2017_43] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The voltage-gated cardiac sodium channel (Nav1.5) is a mega-complex comprised of a pore-forming α subunit and 4 ancillary β-subunits together with numerous protein partners. Genetic defects in the form of rare variants in one or more sodium channel-related genes can cause a loss- or gain-of-function of sodium channel current (INa) leading to the manifestation of various disease phenotypes, including Brugada syndrome, long QT syndrome, progressive cardiac conduction disease, sick sinus syndrome, multifocal ectopic Purkinje-related premature contractions, and atrial fibrillation. Some sodium channelopathies have also been shown to be responsible for sudden infant death syndrome (SIDS). Although these genetic defects often present as pure electrical diseases, recent studies point to a contribution of structural abnormalities to the electrocardiographic and arrhythmic manifestation in some cases, such as dilated cardiomyopathy. The same rare variants in SCN5A or related genes may present with different clinical phenotypes in different individuals and sometimes in members of the same family. Genetic background and epigenetic and environmental factors contribute to the expression of these overlap syndromes. Our goal in this chapter is to review and discuss what is known about the clinical phenotype and genotype of each cardiac sodium channelopathy, and to briefly discuss the underlying mechanisms.
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Affiliation(s)
| | - Mariana Argenziano
- Lankenau Institute for Medical Research, 100 E. Lancaster Avenue, Wynnewood, PA, 19096, USA
| | - Charles Antzelevitch
- Lankenau Institute for Medical Research, 100 E. Lancaster Avenue, Wynnewood, PA, 19096, USA.
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Biophysical comparison of sodium currents in native cardiac myocytes and human induced pluripotent stem cell-derived cardiomyocytes. J Pharmacol Toxicol Methods 2017; 90:19-30. [PMID: 29128504 DOI: 10.1016/j.vascn.2017.11.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 09/22/2017] [Accepted: 11/02/2017] [Indexed: 12/31/2022]
Abstract
INTRODUCTION Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are used for safety pharmacology and to investigate genetic diseases affecting cardiac ion channels. It is unclear whether adult myocytes or hiPSC-CMs are the better platform for cardiac safety pharmacology. We examined the biophysical and molecular properties of INa in adult myocytes and hiPSC-CMs. METHODS hiPSC-CMs were plated at low density. Atrial and ventricular cells were obtained from dog hearts. Whole cell patch clamp was used to record INa. RESULTS Voltage clamp recordings showed a large INa in all three cell types but different densities. Small differences in steady-state inactivation and recovery from inactivation were noted in the three cell types. Application of lidocaine to the three cell types showed a similar pattern of block of INa under voltage clamp; however, lidocaine produced different effects on AP waveform under current clamp. AP clamp experiments showed that application of ventricular or atrial cell waveforms to the same hiPSC-CM elicited a large INa while application of a sinoatrial node waveform elicited no INa. Molecular analysis of Na+ channel subunits showed SCN5A and SCN1B-4B were expressed in adult cells and iPSC-CMs. However, iPSC-CMs express both fetal (exon 6A) and adult (exon 6) isoforms of SCN5A. DISCUSSION There are major differences in INa density and smaller differences in other biophysical properties of INa in adult atrial, ventricular, and hiPSC-CMs. The depolarized maximum diastolic potential coupled with the presence of phase 4 depolarization limits the contribution of INa in hiPSC-CM action potentials. Our results suggest that hiPSC-CMs may be useful for drug screening of Na+ channel inhibitors under voltage clamp but not current clamp.
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Fay KA, Villeneuve DL, LaLone CA, Song Y, Tollefsen KE, Ankley GT. Practical approaches to adverse outcome pathway development and weight-of-evidence evaluation as illustrated by ecotoxicological case studies. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2017; 36:1429-1449. [PMID: 28198554 PMCID: PMC6058314 DOI: 10.1002/etc.3770] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 11/14/2016] [Accepted: 02/13/2017] [Indexed: 05/20/2023]
Abstract
Adverse outcome pathways (AOPs) describe toxicant effects as a sequential chain of causally linked events beginning with a molecular perturbation and culminating in an adverse outcome at an individual or population level. Strategies for developing AOPs are still evolving and depend largely on the intended use or motivation for development and data availability. The present review describes 4 ecotoxicological AOP case studies, developed for different purposes. In each situation, creation of the AOP began in a manner determined by the initial motivation for its creation and expanded either to include additional components of the pathway or to address the domains of applicability in terms of chemical initiators, susceptible species, life stages, and so forth. Some general strategies can be gleaned from these case studies, which a developer may find to be useful for supporting an existing AOP or creating a new one. Several web-based tools that can aid in AOP assembly and evaluation of weight of evidence for scientific robustness of AOP components are highlighted. Environ Toxicol Chem 2017;36:1429-1449. © 2017 SETAC.
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Affiliation(s)
- Kellie A. Fay
- Mid Continent Ecology Division, U.S. EPA, Duluth, Minnesota
- University of Minnesota – Duluth, Duluth, Minnesota, USA
- Address correspondence to
| | | | | | - You Song
- Norwegian Institute for Water Research (NIVA), Oslo, Norway
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Application of optical action potentials in human induced pluripotent stem cells-derived cardiomyocytes to predict drug-induced cardiac arrhythmias. J Pharmacol Toxicol Methods 2017; 87:53-67. [PMID: 28501647 DOI: 10.1016/j.vascn.2017.05.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 04/25/2017] [Accepted: 05/08/2017] [Indexed: 12/31/2022]
Abstract
INTRODUCTION Human induced pluripotent stem cell-derived cardiomyocytes (hiPS-CMs) are emerging as new and human-relevant source in vitro model for cardiac safety assessment that allow us to investigate a set of 20 reference drugs for predicting cardiac arrhythmogenic liability using optical action potential (oAP) assay. METHODS Here, we describe our examination of the oAP measurement using a voltage sensitive dye (Di-4-ANEPPS) to predict adverse compound effects using hiPS-CMs and 20 cardioactive reference compounds. Fluorescence signals were digitized at 10kHz and the records subsequently analyzed off-line. Cells were exposed to 30min incubation to vehicle or compound (n=5/dose, 4 doses/compound) that were blinded to the investigating laboratory. Action potential parameters were measured, including rise time (Trise) of the optical action potential duration (oAPD). RESULTS Significant effects on oAPD were sensitively detected with 11 QT-prolonging drugs, while oAPD shortening was observed with ICa-antagonists, IKr-activator or ATP-sensitive K+ channel (KATP)-opener. Additionally, the assay detected varied effects induced by 6 different sodium channel blockers. The detection threshold for these drug effects was at or below the published values of free effective therapeutic plasma levels or effective concentrations by other studies. DISCUSSION The results of this blinded study indicate that OAP is a sensitive method to accurately detect drug-induced effects (i.e., duration/QT-prolongation, shortening, beat rate, and incidence of early after depolarizations) in hiPS-CMs; therefore, this technique will potentially be useful in predicting drug-induced arrhythmogenic liabilities in early de-risking within the drug discovery phase.
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Deuis JR, Mueller A, Israel MR, Vetter I. The pharmacology of voltage-gated sodium channel activators. Neuropharmacology 2017; 127:87-108. [PMID: 28416444 DOI: 10.1016/j.neuropharm.2017.04.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 03/28/2017] [Accepted: 04/10/2017] [Indexed: 12/19/2022]
Abstract
Toxins and venom components that target voltage-gated sodium (NaV) channels have evolved numerous times due to the importance of this class of ion channels in the normal physiological function of peripheral and central neurons as well as cardiac and skeletal muscle. NaV channel activators in particular have been isolated from the venom of spiders, wasps, snakes, scorpions, cone snails and sea anemone and are also produced by plants, bacteria and algae. These compounds have provided key insight into the molecular structure, function and pathophysiological roles of NaV channels and are important tools due to their at times exquisite subtype-selectivity. We review the pharmacology of NaV channel activators with particular emphasis on mammalian isoforms and discuss putative applications for these compounds. This article is part of the Special Issue entitled 'Venom-derived Peptides as Pharmacological Tools.'
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Affiliation(s)
- Jennifer R Deuis
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, St Lucia, Qld 4072, Australia
| | - Alexander Mueller
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, St Lucia, Qld 4072, Australia
| | - Mathilde R Israel
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, St Lucia, Qld 4072, Australia
| | - Irina Vetter
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, St Lucia, Qld 4072, Australia; School of Pharmacy, The University of Queensland, Woolloongabba, Qld 4102, Australia.
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Vetter I, Deuis JR, Mueller A, Israel MR, Starobova H, Zhang A, Rash LD, Mobli M. NaV1.7 as a pain target – From gene to pharmacology. Pharmacol Ther 2017; 172:73-100. [DOI: 10.1016/j.pharmthera.2016.11.015] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Johnstone VPA, Viola HM, Hool LC. Dystrophic Cardiomyopathy-Potential Role of Calcium in Pathogenesis, Treatment and Novel Therapies. Genes (Basel) 2017; 8:genes8040108. [PMID: 28338606 PMCID: PMC5406855 DOI: 10.3390/genes8040108] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 03/16/2017] [Accepted: 03/21/2017] [Indexed: 01/06/2023] Open
Abstract
Duchenne muscular dystrophy (DMD) is caused by defects in the DMD gene and results in progressive wasting of skeletal and cardiac muscle due to an absence of functional dystrophin. Cardiomyopathy is prominent in DMD patients, and contributes significantly to mortality. This is particularly true following respiratory interventions that reduce death rate and increase ambulation and consequently cardiac load. Cardiomyopathy shows an increasing prevalence with age and disease progression, and over 95% of patients exhibit dilated cardiomyopathy by the time they reach adulthood. Development of the myopathy is complex, and elevations in intracellular calcium, functional muscle ischemia, and mitochondrial dysfunction characterise the pathophysiology. Current therapies are limited to treating symptoms of the disease and there is therefore an urgent need to treat the underlying genetic defect. Several novel therapies are outlined here, and the unprecedented success of phosphorodiamidate morpholino oligomers (PMOs) in preclinical and clinical studies is overviewed.
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Affiliation(s)
- Victoria P A Johnstone
- School of Human Sciences, The University of Western Australia, Crawley, WA 6009, Australia.
| | - Helena M Viola
- School of Human Sciences, The University of Western Australia, Crawley, WA 6009, Australia.
| | - Livia C Hool
- School of Human Sciences, The University of Western Australia, Crawley, WA 6009, Australia.
- Victor Chang Cardiac Research Institute, Sydney, NSW 2010, Australia.
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Abstract
Cardiac arrhythmias can follow disruption of the normal cellular electrophysiological processes underlying excitable activity and their tissue propagation as coherent wavefronts from the primary sinoatrial node pacemaker, through the atria, conducting structures and ventricular myocardium. These physiological events are driven by interacting, voltage-dependent, processes of activation, inactivation, and recovery in the ion channels present in cardiomyocyte membranes. Generation and conduction of these events are further modulated by intracellular Ca2+ homeostasis, and metabolic and structural change. This review describes experimental studies on murine models for known clinical arrhythmic conditions in which these mechanisms were modified by genetic, physiological, or pharmacological manipulation. These exemplars yielded molecular, physiological, and structural phenotypes often directly translatable to their corresponding clinical conditions, which could be investigated at the molecular, cellular, tissue, organ, and whole animal levels. Arrhythmogenesis could be explored during normal pacing activity, regular stimulation, following imposed extra-stimuli, or during progressively incremented steady pacing frequencies. Arrhythmic substrate was identified with temporal and spatial functional heterogeneities predisposing to reentrant excitation phenomena. These could arise from abnormalities in cardiac pacing function, tissue electrical connectivity, and cellular excitation and recovery. Triggering events during or following recovery from action potential excitation could thereby lead to sustained arrhythmia. These surface membrane processes were modified by alterations in cellular Ca2+ homeostasis and energetics, as well as cellular and tissue structural change. Study of murine systems thus offers major insights into both our understanding of normal cardiac activity and its propagation, and their relationship to mechanisms generating clinical arrhythmias.
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Affiliation(s)
- Christopher L-H Huang
- Physiological Laboratory and the Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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35
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Patel F, Brackenbury WJ. Dual roles of voltage-gated sodium channels in development and cancer. THE INTERNATIONAL JOURNAL OF DEVELOPMENTAL BIOLOGY 2016; 59:357-66. [PMID: 26009234 DOI: 10.1387/ijdb.150171wb] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Voltage-gated Na(+) channels (VGSCs) are heteromeric protein complexes containing pore-forming α subunits together with non-pore-forming β subunits. There are nine α subunits, Nav1.1-Nav1.9, and four β subunits, β1-β4. The β subunits are multifunctional, modulating channel activity, cell surface expression, and are members of the immunoglobulin superfamily of cell adhesion molecules. VGSCs are classically responsible for action potential initiation and conduction in electrically excitable cells, including neurons and muscle cells. In addition, through the β1 subunit, VGSCs regulate neurite outgrowth and pathfinding in the developing central nervous system. Reciprocal signalling through Nav1.6 and β1 collectively regulates Na(+) current, electrical excitability and neurite outgrowth in cerebellar granule neurons. Thus, α and β subunits may have diverse interacting roles dependent on cell/tissue type. VGSCs are also expressed in non-excitable cells, including cells derived from a number of types of cancer. In cancer cells, VGSC α and β subunits regulate cellular morphology, migration, invasion and metastasis. VGSC expression associates with poor prognosis in several studies. It is hypothesised that VGSCs are up-regulated in metastatic tumours, favouring an invasive phenotype. Thus, VGSCs may have utility as prognostic markers, and/or as novel therapeutic targets for reducing/preventing metastatic disease burden. VGSCs appear to regulate a number of key cellular processes, both during normal postnatal development of the CNS and during cancer metastasis, by a combination of conducting (i.e. via Na(+) current) and non-conducting mechanisms.
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Molina CE, Heijman J, Dobrev D. Differences in Left Versus Right Ventricular Electrophysiological Properties in Cardiac Dysfunction and Arrhythmogenesis. Arrhythm Electrophysiol Rev 2016; 5:14-9. [PMID: 27403288 DOI: 10.15420/aer.2016.8.2] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
A wide range of ion channels, transporters, signaling pathways and tissue structure at a microscopic and macroscopic scale regulate the electrophysiological activity of the heart. Each region of the heart has optimised these properties based on its specific role during the cardiac cycle, leading to well-established differences in electrophysiology, Ca(2+) handling and tissue structure between atria and ventricles and between different layers of the ventricular wall. Similarly, the right ventricle (RV) and left ventricle (LV) have different embryological, structural, metabolic and electrophysiological features, but whether interventricular differences promote differential remodeling leading to arrhythmias is not well understood. In this article, we will summarise the available data on intrinsic differences between LV and RV electrophysiology and indicate how these differences affect cardiac function. Furthermore, we will discuss the differential remodeling of both chambers in pathological conditions and its potential impact on arrhythmogenesis.
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Affiliation(s)
- Cristina E Molina
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
| | - Jordi Heijman
- Cardiovascular Research Institute Maastricht, Faculty of Health, Medicine, and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
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37
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Distinctive property and pharmacology of voltage-gated sodium current in rat atrial vs ventricular myocytes. Heart Rhythm 2016; 13:762-70. [DOI: 10.1016/j.hrthm.2015.11.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Indexed: 02/01/2023]
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38
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Zaklyazminskaya E, Dzemeshkevich S. The role of mutations in the SCN5A gene in cardiomyopathies. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:1799-805. [PMID: 26916278 DOI: 10.1016/j.bbamcr.2016.02.014] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Revised: 02/17/2016] [Accepted: 02/19/2016] [Indexed: 12/18/2022]
Abstract
The SCN5A gene encodes the alpha-subunit of the Nav1.5 ion channel protein, which is responsible for the sodium inward current (INa). Since 1995 several hundred mutations in this gene have been found to be causative for inherited arrhythmias including Long QT syndrome, Brugada syndrome, cardiac conduction disease, sudden infant death syndrome, etc. As expected these syndromes are primarily electrical heart diseases leading to life-threatening arrhythmias with an "apparently normal heart". In 2003 a new form of dilated cardiomyopathy was identified associated with mutations in the SCN5A gene. Recently mutations have been also found in patients with arrhythmogenic right ventricular cardiomyopathy and atrial standstill. The purpose of this review is to outline and analyze the following four topics: 1) SCN5A genetic variants linked to different cardiomyopathies; 2) clinical manifestations of the known mutations; 3) possible molecular mechanisms of myocardial remodeling; and 4) the potential implications of gene-specific treatment for those disorders. 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)
- Elena Zaklyazminskaya
- Petrovsky Russian Research Centre of Surgery, Abricosovsky pereulok, 119991 Moscow, Russia; Department of Molecular and Cellular Genetics, Pirogov Russian National Research Medical University, Ostrovityanova str. 1, Moscow 117997, Russia.
| | - Sergei Dzemeshkevich
- Petrovsky Russian Research Centre of Surgery, Abricosovsky pereulok, 119991 Moscow, Russia.
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Jeevaratnam K, Guzadhur L, Goh YM, Grace AA, Huang CLH. Sodium channel haploinsufficiency and structural change in ventricular arrhythmogenesis. Acta Physiol (Oxf) 2016; 216:186-202. [PMID: 26284956 DOI: 10.1111/apha.12577] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 06/11/2015] [Accepted: 07/24/2015] [Indexed: 12/19/2022]
Abstract
Normal cardiac excitation involves orderly conduction of electrical activation and recovery dependent upon surface membrane, voltage-gated, sodium (Na(+) ) channel α-subunits (Nav 1.5). We summarize experimental studies of physiological and clinical consequences of loss-of-function Na(+) channel mutations. Of these conditions, Brugada syndrome (BrS) and progressive cardiac conduction defect (PCCD) are associated with sudden, often fatal, ventricular tachycardia (VT) or fibrillation. Mouse Scn5a(+/-) hearts replicate important clinical phenotypes modelling these human conditions. The arrhythmic phenotype is associated not only with the primary biophysical change but also with additional, anatomical abnormalities, in turn dependent upon age and sex, each themselves exerting arrhythmic effects. Available evidence suggests a unified binary scheme for the development of arrhythmia in both BrS and PCCD. Previous biophysical studies suggested that Nav 1.5 deficiency produces a background electrophysiological defect compromising conduction, thereby producing an arrhythmic substrate unmasked by flecainide or ajmaline challenge. More recent reports further suggest a progressive decline in conduction velocity and increase in its dispersion particularly in ageing male Nav 1.5 haploinsufficient compared to WT hearts. This appears to involve a selective appearance of slow conduction at the expense of rapidly conducting pathways with changes in their frequency distributions. These changes were related to increased cardiac fibrosis. It is thus the combination of the structural and biophysical changes both accentuating arrhythmic substrate that may produce arrhythmic tendency. This binary scheme explains the combined requirement for separate, biophysical and structural changes, particularly occurring in ageing Nav 1.5 haploinsufficient males in producing clinical arrhythmia.
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Affiliation(s)
- K. Jeevaratnam
- Faculty of Health and Medical Science; University of Surrey; Guilford UK
- Perdana University - Royal College of Surgeons Ireland; Serdang Selangor Darul Ehsan Malaysia
| | - L. Guzadhur
- Division of Cardiovascular Biology; Department of Biochemistry; University of Cambridge; Cambridge UK
- Niche Science & Technology; Richmond UK
| | - Y. M. Goh
- Department of Preclinical Sciences; Faculty of Veterinary Medicine; University Putra Malaysia; Serdang Selangor Darul Ehsan Malaysia
| | - A. A. Grace
- Division of Cardiovascular Biology; Department of Biochemistry; University of Cambridge; Cambridge UK
| | - C. L.-H. Huang
- Division of Cardiovascular Biology; Department of Biochemistry; University of Cambridge; Cambridge UK
- Physiological Laboratory; University of Cambridge; Cambridge UK
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Leo-Macias A, Agullo-Pascual E, Sanchez-Alonso JL, Keegan S, Lin X, Arcos T, Feng-Xia-Liang, Korchev YE, Gorelik J, Fenyö D, Rothenberg E, Rothenberg E, Delmar M. Nanoscale visualization of functional adhesion/excitability nodes at the intercalated disc. Nat Commun 2016; 7:10342. [PMID: 26787348 PMCID: PMC4735805 DOI: 10.1038/ncomms10342] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 12/01/2015] [Indexed: 02/06/2023] Open
Abstract
Intercellular adhesion and electrical excitability are considered separate cellular properties. Studies of myelinated fibres, however, show that voltage-gated sodium channels (VGSCs) aggregate with cell adhesion molecules at discrete subcellular locations, such as the nodes of Ranvier. Demonstration of similar macromolecular organization in cardiac muscle is missing. Here we combine nanoscale-imaging (single-molecule localization microscopy; electron microscopy; and ‘angle view' scanning patch clamp) with mathematical simulations to demonstrate distinct hubs at the cardiac intercalated disc, populated by clusters of the adhesion molecule N-cadherin and the VGSC NaV1.5. We show that the N-cadherin-NaV1.5 association is not random, that NaV1.5 molecules in these clusters are major contributors to cardiac sodium current, and that loss of NaV1.5 expression reduces intercellular adhesion strength. We speculate that adhesion/excitability nodes are key sites for crosstalk of the contractile and electrical molecular apparatus and may represent the structural substrate of cardiomyopathies in patients with mutations in molecules of the VGSC complex. In myelinated fibres conduction and adhesion proteins aggregate at discrete foci, but it is unclear if this organization is present in other excitable cells. Using nanoscale visualization and in silico techniques, the authors show that adhesion/excitability nodes exist at the intercalated discs of adult cardiac muscle.
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Affiliation(s)
- Alejandra Leo-Macias
- The Leon H Charney Division of Cardiology, New York University School of Medicine (NYU-SoM), 522 First Avenue, Smilow 805, New York, New York 10016, USA
| | - Esperanza Agullo-Pascual
- The Leon H Charney Division of Cardiology, New York University School of Medicine (NYU-SoM), 522 First Avenue, Smilow 805, New York, New York 10016, USA
| | - Jose L Sanchez-Alonso
- Imperial College, National Heart and Lung Institute, Department of Cardiac Medicine, Imperial Center for Translational and Experimental Medicine, Hammersmith Campus, Du Cane Road, London W12 0NN, UK
| | - Sarah Keegan
- Center for Health Informatics and Bioinformatics, NYU-SoM, Translational Research Building, 227 East 30th Street, New York, New York 10016, USA
| | - Xianming Lin
- The Leon H Charney Division of Cardiology, New York University School of Medicine (NYU-SoM), 522 First Avenue, Smilow 805, New York, New York 10016, USA
| | - Tatiana Arcos
- The Leon H Charney Division of Cardiology, New York University School of Medicine (NYU-SoM), 522 First Avenue, Smilow 805, New York, New York 10016, USA
| | - Feng-Xia-Liang
- Microscopy Core, NYU-SoM, 522 First Avenue, Skirball Institute, 2nd Floor, New York, New York 10016, USA
| | - Yuri E Korchev
- Division of Medicine, Imperial College, Hammersmith Campus, Du Cane Road, London, London W12 0NN, UK
| | - Julia Gorelik
- Imperial College, National Heart and Lung Institute, Department of Cardiac Medicine, Imperial Center for Translational and Experimental Medicine, Hammersmith Campus, Du Cane Road, London W12 0NN, UK
| | - David Fenyö
- Center for Health Informatics and Bioinformatics, NYU-SoM, Translational Research Building, 227 East 30th Street, New York, New York 10016, USA
| | - Eli Rothenberg
- Department of Biochemistry and Molecular Pharmacology, NYU-SoM, 522 First Avenue, MSB 3rd Floor, New York, New York 10016, USA
| | | | - Mario Delmar
- The Leon H Charney Division of Cardiology, New York University School of Medicine (NYU-SoM), 522 First Avenue, Smilow 805, New York, New York 10016, USA
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41
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Effects of the β1 auxiliary subunit on modification of Rat Na(v)1.6 sodium channels expressed in HEK293 cells by the pyrethroid insecticides tefluthrin and deltamethrin. Toxicol Appl Pharmacol 2015; 291:58-69. [PMID: 26708501 DOI: 10.1016/j.taap.2015.12.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 12/09/2015] [Accepted: 12/16/2015] [Indexed: 11/22/2022]
Abstract
We expressed rat Nav1.6 sodium channels with or without the rat β1 subunit in human embryonic kidney (HEK293) cells and evaluated the effects of the pyrethroid insecticides tefluthrin and deltamethrin on whole-cell sodium currents. In assays with the Nav1.6 α subunit alone, both pyrethroids prolonged channel inactivation and deactivation and shifted the voltage dependence of channel activation and steady-state inactivation toward hyperpolarization. Maximal shifts in activation were ~18 mV for tefluthrin and ~24 mV for deltamethrin. These compounds also caused hyperpolarizing shifts of ~10-14 mV in the voltage dependence of steady-state inactivation and increased in the fraction of sodium current that was resistant to inactivation. The effects of pyrethroids on the voltage-dependent gating greatly increased the size of sodium window currents compared to unmodified channels; modified channels exhibited increased probability of spontaneous opening at membrane potentials more negative than the normal threshold for channel activation and incomplete channel inactivation. Coexpression of Nav1.6 with the β1 subunit had no effect on the kinetic behavior of pyrethroid-modified channels but had divergent effects on the voltage-dependent gating of tefluthrin- or deltamethrin-modified channels, increasing the size of tefluthrin-induced window currents but decreasing the size of corresponding deltamethrin-induced currents. Unexpectedly, the β1 subunit did not confer sensitivity to use-dependent channel modification by either tefluthrin or deltamethrin. We conclude from these results that functional reconstitution of channels in vitro requires careful attention to the subunit composition of channel complexes to ensure that channels in vitro are faithful functional and pharmacological models of channels in neurons.
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42
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Signore S, Sorrentino A, Borghetti G, Cannata A, Meo M, Zhou Y, Kannappan R, Pasqualini F, O'Malley H, Sundman M, Tsigkas N, Zhang E, Arranto C, Mangiaracina C, Isobe K, Sena BF, Kim J, Goichberg P, Nahrendorf M, Isom LL, Leri A, Anversa P, Rota M. Late Na(+) current and protracted electrical recovery are critical determinants of the aging myopathy. Nat Commun 2015; 6:8803. [PMID: 26541940 PMCID: PMC4638135 DOI: 10.1038/ncomms9803] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 10/02/2015] [Indexed: 12/19/2022] Open
Abstract
The aging myopathy manifests itself with diastolic dysfunction and preserved ejection fraction. We raised the possibility that, in a mouse model of physiological aging, defects in electromechanical properties of cardiomyocytes are important determinants of the diastolic characteristics of the myocardium, independently from changes in structural composition of the muscle and collagen framework. Here we show that an increase in the late Na(+) current (INaL) in aging cardiomyocytes prolongs the action potential (AP) and influences temporal kinetics of Ca(2+) cycling and contractility. These alterations increase force development and passive tension. Inhibition of INaL shortens the AP and corrects dynamics of Ca(2+) transient, cell contraction and relaxation. Similarly, repolarization and diastolic tension of the senescent myocardium are partly restored. Thus, INaL offers inotropic support, but negatively interferes with cellular and ventricular compliance, providing a new perspective of the biology of myocardial aging and the aetiology of the defective cardiac performance in the elderly.
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Affiliation(s)
- Sergio Signore
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, 20 Shattuck Street, Boston, Massachusetts 02115, USA
| | - Andrea Sorrentino
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, 20 Shattuck Street, Boston, Massachusetts 02115, USA
| | - Giulia Borghetti
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, 20 Shattuck Street, Boston, Massachusetts 02115, USA
| | - Antonio Cannata
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, 20 Shattuck Street, Boston, Massachusetts 02115, USA
| | - Marianna Meo
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, 20 Shattuck Street, Boston, Massachusetts 02115, USA
| | - Yu Zhou
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, 20 Shattuck Street, Boston, Massachusetts 02115, USA
| | - Ramaswamy Kannappan
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, 20 Shattuck Street, Boston, Massachusetts 02115, USA
| | - Francesco Pasqualini
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, 20 Shattuck Street, Boston, Massachusetts 02115, USA
| | - Heather O'Malley
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Mark Sundman
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, 20 Shattuck Street, Boston, Massachusetts 02115, USA
| | - Nikolaos Tsigkas
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, 20 Shattuck Street, Boston, Massachusetts 02115, USA
| | - Eric Zhang
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, 20 Shattuck Street, Boston, Massachusetts 02115, USA
| | - Christian Arranto
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, 20 Shattuck Street, Boston, Massachusetts 02115, USA
| | - Chiara Mangiaracina
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, 20 Shattuck Street, Boston, Massachusetts 02115, USA
| | - Kazuya Isobe
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, 20 Shattuck Street, Boston, Massachusetts 02115, USA
| | - Brena F Sena
- Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
| | - Junghyun Kim
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, 20 Shattuck Street, Boston, Massachusetts 02115, USA
| | - Polina Goichberg
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, 20 Shattuck Street, Boston, Massachusetts 02115, USA
| | - Matthias Nahrendorf
- Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
| | - Lori L Isom
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Annarosa Leri
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, 20 Shattuck Street, Boston, Massachusetts 02115, USA
| | - Piero Anversa
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, 20 Shattuck Street, Boston, Massachusetts 02115, USA
| | - Marcello Rota
- Departments of Anesthesia and Medicine and Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, 20 Shattuck Street, Boston, Massachusetts 02115, USA
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43
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Age-dependent alterations of voltage-gated Na(+) channel isoforms in rat sinoatrial node. Mech Ageing Dev 2015; 152:80-90. [PMID: 26528804 DOI: 10.1016/j.mad.2015.10.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2015] [Revised: 10/08/2015] [Accepted: 10/26/2015] [Indexed: 02/06/2023]
Abstract
Multiple isoforms of voltage-gated Na(+) channels (NaChs) have been identified in sinoatrial node (SAN) and contribute to a rapid intrinsic heart rate. However, their roles in aging remain unclear. Here, we sought to clarify whether the age-related expression of NaChs contributes to the impaired SAN function during aging. Blockade of the tetrodotoxin (TTX)-sensitive Na(+) current with nanomolar concentrations of TTX prolonged the cycle length (CL) in both the rat intact heart and SAN. The effect of nanomolar concentrations of TTX on SAN pacemaking was lessened in adulthood compared with that in youth. Interestingly, the pacemaking became more sensitive to TTX and TTX-induced sinus arrhythmias occurred more frequently in the senescent group. The presences of NaCh α subunit isoforms Nav1.1, Nav1.6 as well as β subunit isoforms Navβ1 and Navβ3 in SAN were confirmed by immunohistochemistry. Western blot revealed a declination of Nav1.1, Nav1.6, Navβ1 and Navβ3 proteins during aging. Furthermore, laser captured SAN cells were used for further real-time quantitative RT-PCR analysis, which also confirmed the presences of Nav1.1, Nav1.6, Navβ1 and Navβ3 mRNA and their reduced levels in rat SAN during aging. These results indicated an age-dependent alterations in expression and relative function of NaCh in rat SAN.
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44
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Veerman CC, Wilde AAM, Lodder EM. The cardiac sodium channel gene SCN5A and its gene product NaV1.5: Role in physiology and pathophysiology. Gene 2015; 573:177-87. [PMID: 26361848 DOI: 10.1016/j.gene.2015.08.062] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 07/31/2015] [Accepted: 08/27/2015] [Indexed: 12/18/2022]
Abstract
The gene SCN5A encodes the main cardiac sodium channel NaV1.5. This channel predominates the cardiac sodium current, INa, which underlies the fast upstroke of the cardiac action potential. As such, it plays a crucial role in cardiac electrophysiology. Over the last 60years a tremendous amount of knowledge regarding its function at the electrophysiological and molecular level has been acquired. Furthermore, genetic studies have shown that mutations in SCN5A are associated with multiple cardiac diseases (e.g. Brugada syndrome, Long QT syndrome, conduction disease and cardiomyopathy), while genetic variation in the general population has been associated with differences in cardiac conduction and risk of arrhythmia through genome wide association studies. In this review we aim to give an overview of the current knowledge (and the gaps therein) on SCN5A and NaV1.5.
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Affiliation(s)
- Christiaan C Veerman
- Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands
| | - Arthur A M Wilde
- Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands.
| | - Elisabeth M Lodder
- Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands.
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45
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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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46
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Zhang XD, Lieu DK, Chiamvimonvat N. Small-conductance Ca2+ -activated K+ channels and cardiac arrhythmias. Heart Rhythm 2015; 12:1845-51. [PMID: 25956967 PMCID: PMC4662728 DOI: 10.1016/j.hrthm.2015.04.046] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Indexed: 01/04/2023]
Abstract
Small-conductance Ca2+ -activated K+ (SK, KCa2) channels are unique in that they are gated solely by changes in intracellular Ca2+ and, hence, function to integrate intracellular Ca2+ and membrane potentials on a beat-to-beat basis. Recent studies have provided evidence for the existence and functional significance of SK channels in the heart. Indeed, our knowledge of cardiac SK channels has been greatly expanded over the past decade. Interests in cardiac SK channels are further driven by recent studies suggesting the critical roles of SK channels in human atrial fibrillation, the SK channel as a possible novel therapeutic target in atrial arrhythmias, and upregulation of SK channels in heart failure in animal models and in human heart failure. However, there remain critical gaps in our knowledge. Specifically, blockade of SK channels in cardiac arrhythmias has been shown to be both antiarrhythmic and proarrhythmic. This contemporary review provides an overview of the literature on the role of cardiac SK channels in cardiac arrhythmias and serves as a discussion platform for the current clinical perspectives. At the translational level, development of SK channel blockers as a new therapeutic strategy in the treatment of atrial fibrillation and the possible proarrhythmic effects merit further considerations and investigations.
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Affiliation(s)
- Xiao-Dong Zhang
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, California.
| | - Deborah K Lieu
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, California
| | - Nipavan Chiamvimonvat
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, California; Department of Veterans Affairs, Northern California Health Care System, Mather, California.
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47
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The role of the sodium current complex in a nonreferred nationwide cohort of sudden infant death syndrome. Heart Rhythm 2015; 12:1241-9. [DOI: 10.1016/j.hrthm.2015.03.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Indexed: 11/18/2022]
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48
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Chapalamadugu K, Panguluri SK, Miranda A, Sneed KB, Tipparaju SM. Pharmacogenomics of cardiovascular complications in diabetes and obesity. Recent Pat Biotechnol 2015; 8:123-35. [PMID: 25185978 DOI: 10.2174/1872208309666140904123023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 06/25/2014] [Accepted: 07/05/2014] [Indexed: 01/03/2023]
Abstract
Heart disease is a major cause of death in US and worldwide. The complex interplay of the mechanisms between diabetes, obesity and inflammation raises concerns for therapeutic understanding and developing treatment options for patients. Recent advances utilizing pharmacogenomics has helped researchers to probe in to disease pathophysiology and physicians to detect and, diagnose the disease in patients. The understanding developed in the area primarily addresses the issue focusing on the nature and asks the question 'Why' some individuals respond to the standard medication regimen and others do not. The central idea that genomics play a vital part in how the healthcare providers: physician, pharmacist, and nurse provide treatment utilizing the best practices available for maximum benefits. Pharmacogenomics is the scientific basis which offers the fundamental understanding for diseases, based on which therapeutic approaches can be designed and delivered. The discovery that not all humans respond to the drug in the same way is a 'paradigm shift' in how current therapies are offered. The area of pharmacogenomics at its core is linked to the genetic basis for the disease and the response to treatment. Given that diabetes and obesity are major metabolic ailments globally wherein patients also often suffer from cardiac disorders, a comprehensive genetic and pharmacogenomic understanding of these conditions enable the development of effective therapeutic strategies. In this review, we discuss various pharmacogenomic approaches with special emphasis on heart disease as it relates to diabetes and obesity. Recent information in regard to relevant patents in this topic are also discussed.
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Affiliation(s)
| | | | | | | | - Srinivas M Tipparaju
- 12901 Bruce B Downs Blvd, MDC030, USF Health College of Pharmacy, Tampa, FL 33612, USA.
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49
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Martin CA, Huang CLH, Matthews GDK. Recent Developments in the Management of Patients at Risk for Sudden Cardiac Death. Postgrad Med 2015; 123:84-94. [DOI: 10.3810/pgm.2011.03.2266] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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50
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Dybkova N, Wagner S, Backs J, Hund TJ, Mohler PJ, Sowa T, Nikolaev VO, Maier LS. Tubulin polymerization disrupts cardiac β-adrenergic regulation of late INa. Cardiovasc Res 2014; 103:168-77. [PMID: 24812278 DOI: 10.1093/cvr/cvu120] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
AIMS The anticancer drug paclitaxel (TXL) that polymerizes microtubules is associated with arrhythmias and sinus node dysfunction. TXL can alter membrane expression of Na channels (NaV1.5) and Na current (INa), but the mechanisms are unknown. Calcium/calmodulin-dependent protein kinase II (CaMKII) can be activated by β-adrenergic stimulation and regulates INa gating. We tested whether TXL interferes with isoproterenol (ISO)-induced activation of CaMKII and consequent INa regulation. METHODS AND RESULTS In wild-type mouse myocytes, the addition of ISO (1 µmol/L) resulted in increased CaMKII auto-phosphorylation (western blotting). This increase was completely abolished after pre-treatment with TXL (100 µmol/L, 1.5 h). The mechanism was further investigated in human embryonic kidney cells. TXL inhibited the ISO-induced β-arrestin translocation. Interestingly, both knockdown of β-arrestin2 expression using small interfering RNA and inhibition of exchange protein directly activated by cAMP (Epac) blocked the ISO-induced CaMKII auto-phosphorylation similar to TXL. The generation of cAMP, however, was unaltered (Epac1-camps). CaMKII-dependent Na channel function was measured using patch-clamp technique in isolated cardiomyoctes. ISO stimulation failed to induce CaMKII-dependent enhancement of late INa and Na channel inactivation (negative voltage shift in steady-state activation and enhanced intermediate inactivation) after pre-incubation with TXL. Consistent with this, TXL also inhibited ISO-induced CaMKII-specific Na channel phosphorylation (at serine 571 of NaV1.5). CONCLUSION Pre-incubation with TXL disrupts the ISO-dependent CaMKII activation and consequent Na channel regulation. This may be important for patients receiving TXL treatments, but also relevant for conditions of increased CaMKII expression and enhanced β-adrenergic stimulation like in heart failure.
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Affiliation(s)
- Nataliya Dybkova
- Clinic for Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | - Stefan Wagner
- Clinic for Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany Department of Internal Medicine II, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, Regensburg 93053, Germany
| | - Johannes Backs
- Department of Cardiology, Angiology and Pneumology, Ruprecht Karls University Heidelberg, Heidelberg, Germany DZHK, Partner Site Heidelberg, Heidelberg, Germany
| | - Thomas J Hund
- Davis Heart and Lung Research Institute, Department of Internal Medicine and Physiology and Cell Biology, Ohio State University Medical Center, Columbus, OH, USA
| | - Peter J Mohler
- Davis Heart and Lung Research Institute, Department of Internal Medicine and Physiology and Cell Biology, Ohio State University Medical Center, Columbus, OH, USA
| | - Thomas Sowa
- Clinic for Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | - Viacheslav O Nikolaev
- Clinic for Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | - Lars S Maier
- Department of Internal Medicine II, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, Regensburg 93053, Germany
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