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Sun X, Lee HC, Lu T. Sorbs2 Deficiency and Vascular BK Channelopathy in Diabetes. Circ Res 2024; 134:858-871. [PMID: 38362769 PMCID: PMC10978258 DOI: 10.1161/circresaha.123.323538] [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: 08/16/2023] [Accepted: 02/02/2024] [Indexed: 02/17/2024]
Abstract
BACKGROUND Vascular large conductance Ca2+-activated K+ (BK) channel, composed of the α-subunit (BK-α) and the β1-subunit (BK-β1), is a key determinant of coronary vasorelaxation and its function is impaired in diabetic vessels. However, our knowledge of diabetic BK channel dysregulation is incomplete. The Sorbs2 (Sorbin homology [SoHo] and Src homology 3 [SH3] domains-containing protein 2), is ubiquitously expressed in arteries, but its role in vascular pathophysiology is unknown. METHODS The role of Sorbs2 in regulating vascular BK channel activity was determined using patch-clamp recordings, molecular biological techniques, and in silico analysis. RESULTS Sorbs2 is not only a cytoskeletal protein but also an RNA-binding protein that binds to BK channel proteins and BK-α mRNA, regulating BK channel expression and function in coronary smooth muscle cells. Molecular biological studies reveal that the SH3 domain of Sorbs2 is necessary for Sorbs2 interaction with BK-α subunits, while both the SH3 and SoHo domains of Sorbs2 interact with BK-β1 subunits. Deletion of the SH3 or SoHo domains abolishes the Sorbs2 effect on the BK-α/BK-β1 channel current density. Additionally, Sorbs2 is a target gene of the Nrf2 (nuclear factor erythroid-2-related factor 2), which binds to the promoter of Sorbs2 and regulates Sorbs2 expression in coronary smooth muscle cells. In vivo studies demonstrate that Sorbs2 knockout mice at 4 months of age display a significant decrease in BK channel expression and function, accompanied by impaired BK channel Ca2+-sensitivity and BK channel-mediated vasodilation in coronary arteries, without altering their body weights and blood glucose levels. Importantly, Sorbs2 expression is significantly downregulated in the coronary arteries of db/db type 2 diabetic mice. CONCLUSIONS Sorbs2, a downstream target of Nrf2, plays an important role in regulating BK channel expression and function in vascular smooth muscle cells. Vascular Sorbs2 is downregulated in diabetes. Genetic knockout of Sorbs2 manifests coronary BK channelopathy and vasculopathy observed in diabetic mice, independent of obesity and glucotoxicity.
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Affiliation(s)
- Xiaojing Sun
- The Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN
| | - Hon-Chi Lee
- The Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN
| | - Tong Lu
- The Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN
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2
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Meier S, Grundland A, Dobrev D, Volders PG, Heijman J. In silico analysis of the dynamic regulation of cardiac electrophysiology by K v 11.1 ion-channel trafficking. J Physiol 2023; 601:2711-2731. [PMID: 36752166 PMCID: PMC10313819 DOI: 10.1113/jp283976] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 01/30/2023] [Indexed: 02/09/2023] Open
Abstract
Cardiac electrophysiology is regulated by continuous trafficking and internalization of ion channels occurring over minutes to hours. Kv 11.1 (also known as hERG) underlies the rapidly activating delayed-rectifier K+ current (IKr ), which plays a major role in cardiac ventricular repolarization. Experimental characterization of the distinct temporal effects of genetic and acquired modulators on channel trafficking and gating is challenging. Computer models are instrumental in elucidating these effects, but no currently available model incorporates ion-channel trafficking. Here, we present a novel computational model that reproduces the experimentally observed production, forward trafficking, internalization, recycling and degradation of Kv 11.1 channels, as well as their modulation by temperature, pentamidine, dofetilide and extracellular K+ . The acute effects of these modulators on channel gating were also incorporated and integrated with the trafficking model in the O'Hara-Rudy human ventricular cardiomyocyte model. Supraphysiological dofetilide concentrations substantially increased Kv 11.1 membrane levels while also producing a significant channel block. However, clinically relevant concentrations did not affect trafficking. Similarly, severe hypokalaemia reduced Kv 11.1 membrane levels based on long-term culture data, but had limited effect based on short-term data. By contrast, clinically relevant elevations in temperature acutely increased IKr due to faster kinetics, while after 24 h, IKr was decreased due to reduced Kv 11.1 membrane levels. The opposite was true for lower temperatures. Taken together, our model reveals a complex temporal regulation of cardiac electrophysiology by temperature, hypokalaemia, and dofetilide through competing effects on channel gating and trafficking, and provides a framework for future studies assessing the role of impaired trafficking in cardiac arrhythmias. KEY POINTS: Kv 11.1 channels underlying the rapidly activating delayed-rectifier K+ current are important for ventricular repolarization and are continuously shuttled from the cytoplasm to the plasma membrane and back over minutes to hours. Kv 11.1 gating and trafficking are modulated by temperature, drugs and extracellular K+ concentration but experimental characterization of their combined effects is challenging. Computer models may facilitate these analyses, but no currently available model incorporates ion-channel trafficking. We introduce a new two-state ion-channel trafficking model able to reproduce a wide range of experimental data, along with the effects of modulators of Kv 11.1 channel functioning and trafficking. The model reveals complex dynamic regulation of ventricular repolarization by temperature, extracellular K+ concentration and dofetilide through opposing acute (millisecond) effects on Kv 11.1 gating and long-term (hours) modulation of Kv 11.1 trafficking. This in silico trafficking framework provides a tool to investigate the roles of acute and long-term processes on arrhythmia promotion and maintenance.
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Affiliation(s)
- Stefan Meier
- Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Faculty of Health, Medicine, and Life Sciences, Maastricht University and Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Adaïa Grundland
- Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Faculty of Health, Medicine, and Life Sciences, Maastricht University and Maastricht University Medical Center+, Maastricht, The Netherlands
- Department of Data Science and Knowledge Engineering, Faculty of Science and Engineering, Maastricht University, Maastricht, The Netherlands
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, University of Duisburg-Essen, Essen, Germany
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Medicine and Research Center, Montreal Heart Institute and Université de Montréal, Montréal, Quebec, Canada
| | - Paul G.A. Volders
- Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Faculty of Health, Medicine, and Life Sciences, Maastricht University and Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Jordi Heijman
- Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Faculty of Health, Medicine, and Life Sciences, Maastricht University and Maastricht University Medical Center+, Maastricht, The Netherlands
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d’Apolito M, Santoro F, Santacroce R, Cordisco G, Ragnatela I, D’Arienzo G, Pellegrino PL, Brunetti ND, Margaglione M. A Novel DLG1 Variant in a Family with Brugada Syndrome: Clinical Characteristics and In Silico Analysis. Genes (Basel) 2023; 14:427. [PMID: 36833354 PMCID: PMC9957379 DOI: 10.3390/genes14020427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 01/31/2023] [Accepted: 02/05/2023] [Indexed: 02/10/2023] Open
Abstract
BACKGROUND Brugada syndrome (BrS) is an inherited primary channelopathy syndrome associated to sudden cardiac death. Overall, variants have been identified in eighteen genes encoding for ion channel subunits and seven genes for regulatory proteins. Recently, a missense variant in DLG1 has been found within a BrS phenotype-positive patient. DLG1 encodes for synapse associated protein 97 (SAP97), a protein characterized by the presence of multiple domains for protein-protein interactions including PDZ domains. In cardiomyocytes, SAP97 interacts with Nav1.5, a PDZ binding motif of SCN5A and others potassium channel subunits. AIM OF THE STUDY To characterize the phenotype of an Italian family with BrS syndrome carrying a DLG1 variant. METHODS Clinical and genetic investigations were performed. Genetic testing was performed with whole-exome sequencing (WES) using the Illumina platform. According to the standard protocol, a variant found by WES was confirmed in all members of the family by bi-directional capillary Sanger resequencing. The effect of the variant was investigated by using in silico prediction of pathogenicity. RESULTS The index case was a 74-year-old man with spontaneous type 1 BrS ECG pattern that experienced syncope and underwent ICD implantation. WES of the index case, performed assuming a dominant mode of inheritance, identified a heterozygous variant, c.1556G>A (p.R519H), in the exon 15 of the DLG1 gene. In the pedigree investigation, 6 out of 12 family members had the variant. Carriers of the gene variant all had BrS ECG type 1 drug induced and showed heterogeneous cardiac phenotypes with two patients experiencing syncope during exercise and fever, respectively. The amino acid residue #519 lies near a PDZ domain and in silico analysis suggested a causal role for the variant. Modelling of the resulting protein structure predicted that the variant disrupts an H-bond and a likelihood of being pathogenic. As a consequence, it is likely that a conformational change affects protein functionality and the modulating role on ion channels. CONCLUSIONS A DLG1 gene variant identified was associated with BrS. The variant could modify the formation of multichannel protein complexes, affecting ion channels to specific compartments in cardiomyocytes.
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Affiliation(s)
- Maria d’Apolito
- Medical Genetics, Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy
| | - Francesco Santoro
- Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy
- Cardiology Unit, Polyclinic Hospital of Foggia, 71122 Foggia, Italy
| | - Rosa Santacroce
- Medical Genetics, Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy
| | - Giorgia Cordisco
- Medical Genetics, Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy
| | - Ilaria Ragnatela
- Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy
| | | | | | - Natale Daniele Brunetti
- Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy
- Cardiology Unit, Polyclinic Hospital of Foggia, 71122 Foggia, Italy
| | - Maurizio Margaglione
- Medical Genetics, Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy
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Maltan L, Andova AM, Derler I. The Role of Lipids in CRAC Channel Function. Biomolecules 2022; 12:biom12030352. [PMID: 35327543 PMCID: PMC8944985 DOI: 10.3390/biom12030352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/12/2022] [Accepted: 02/20/2022] [Indexed: 11/28/2022] Open
Abstract
The composition and dynamics of the lipid membrane define the physical properties of the bilayer and consequently affect the function of the incorporated membrane transporters, which also applies for the prominent Ca2+ release-activated Ca2+ ion channel (CRAC). This channel is activated by receptor-induced Ca2+ store depletion of the endoplasmic reticulum (ER) and consists of two transmembrane proteins, STIM1 and Orai1. STIM1 is anchored in the ER membrane and senses changes in the ER luminal Ca2+ concentration. Orai1 is the Ca2+-selective, pore-forming CRAC channel component located in the plasma membrane (PM). Ca2+ store-depletion of the ER triggers activation of STIM1 proteins, which subsequently leads to a conformational change and oligomerization of STIM1 and its coupling to as well as activation of Orai1 channels at the ER-PM contact sites. Although STIM1 and Orai1 are sufficient for CRAC channel activation, their efficient activation and deactivation is fine-tuned by a variety of lipids and lipid- and/or ER-PM junction-dependent accessory proteins. The underlying mechanisms for lipid-mediated CRAC channel modulation as well as the still open questions, are presented in this review.
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Fluorescence Fluctuation Spectroscopy enables quantification of potassium channel subunit dynamics and stoichiometry. Sci Rep 2021; 11:10719. [PMID: 34021177 PMCID: PMC8140153 DOI: 10.1038/s41598-021-90002-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 04/15/2021] [Indexed: 11/08/2022] Open
Abstract
Voltage-gated potassium (Kv) channels are a family of membrane proteins that facilitate K+ ion diffusion across the plasma membrane, regulating both resting and action potentials. Kv channels comprise four pore-forming α subunits, each with a voltage sensing domain, and they are regulated by interaction with β subunits such as those belonging to the KCNE family. Here we conducted a comprehensive biophysical characterization of stoichiometry and protein diffusion across the plasma membrane of the epithelial KCNQ1-KCNE2 complex, combining total internal reflection fluorescence (TIRF) microscopy and a series of complementary Fluorescence Fluctuation Spectroscopy (FFS) techniques. Using this approach, we found that KCNQ1-KCNE2 has a predominant 4:4 stoichiometry, while non-bound KCNE2 subunits are mostly present as dimers in the plasma membrane. At the same time, we identified unique spatio-temporal diffusion modalities and nano-environment organization for each channel subunit. These findings improve our understanding of KCNQ1-KCNE2 channel function and suggest strategies for elucidating the subunit stoichiometry and forces directing localization and diffusion of ion channel complexes in general.
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Askland KD, Strong D, Wright MN, Moore JH. The Translational Machine: A novel machine-learning approach to illuminate complex genetic architectures. Genet Epidemiol 2021; 45:485-536. [PMID: 33942369 DOI: 10.1002/gepi.22383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 03/05/2021] [Accepted: 03/23/2021] [Indexed: 11/08/2022]
Abstract
The Translational Machine (TM) is a machine learning (ML)-based analytic pipeline that translates genotypic/variant call data into biologically contextualized features that richly characterize complex variant architectures and permit greater interpretability and biological replication. It also reduces potentially confounding effects of population substructure on outcome prediction. The TM consists of three main components. First, replicable but flexible feature engineering procedures translate genome-scale data into biologically informative features that appropriately contextualize simple variant calls/genotypes within biological and functional contexts. Second, model-free, nonparametric ML-based feature filtering procedures empirically reduce dimensionality and noise of both original genotype calls and engineered features. Third, a powerful ML algorithm for feature selection is used to differentiate risk variant contributions across variant frequency and functional prediction spectra. The TM simultaneously evaluates potential contributions of variants operative under polygenic and heterogeneous models of genetic architecture. Our TM enables integration of biological information (e.g., genomic annotations) within conceptual frameworks akin to geneset-/pathways-based and collapsing methods, but overcomes some of these methods' limitations. The full TM pipeline is executed in R. Our approach and initial findings from its application to a whole-exome schizophrenia case-control data set are presented. These TM procedures extend the findings of the primary investigation and yield novel results.
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Affiliation(s)
- Kathleen D Askland
- Waypoint Centre for Mental Health Care Penetanguishene, University of Toronto, Toronto, Ontario, Canada
| | - David Strong
- Department of Family Medicine and Public Health, University of California San Diego, San Diego, California, USA
| | - Marvin N Wright
- Department Biometry and Data Management, Leibniz Institute for Prevention Research and Epidemiology - BIPS GmbH, Germany
| | - Jason H Moore
- Department of Biostatistics, Epidemiology, & Informatics, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Yang D, Wan X, Dennis AT, Bektik E, Wang Z, Costa MG, Fagnen C, Vénien-Bryan C, Xu X, Gratz DH, Hund TJ, Mohler PJ, Laurita KR, Deschênes I, Fu JD. MicroRNA Biophysically Modulates Cardiac Action Potential by Direct Binding to Ion Channel. Circulation 2021; 143:1597-1613. [PMID: 33590773 PMCID: PMC8132313 DOI: 10.1161/circulationaha.120.050098] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
BACKGROUND MicroRNAs (miRs) play critical roles in regulation of numerous biological events, including cardiac electrophysiology and arrhythmia, through a canonical RNA interference mechanism. It remains unknown whether endogenous miRs modulate physiologic homeostasis of the heart through noncanonical mechanisms. METHODS We focused on the predominant miR of the heart (miR1) and investigated whether miR1 could physically bind with ion channels in cardiomyocytes by electrophoretic mobility shift assay, in situ proximity ligation assay, RNA pull down, and RNA immunoprecipitation assays. The functional modulations of cellular electrophysiology were evaluated by inside-out and whole-cell patch clamp. Mutagenesis of miR1 and the ion channel was used to understand the underlying mechanism. The effect on the heart ex vivo was demonstrated through investigating arrhythmia-associated human single nucleotide polymorphisms with miR1-deficient mice. RESULTS We found that endogenous miR1 could physically bind with cardiac membrane proteins, including an inward-rectifier potassium channel Kir2.1. The miR1-Kir2.1 physical interaction was observed in mouse, guinea pig, canine, and human cardiomyocytes. miR1 quickly and significantly suppressed IK1 at sub-pmol/L concentration, which is close to endogenous miR expression level. Acute presence of miR1 depolarized resting membrane potential and prolonged final repolarization of the action potential in cardiomyocytes. We identified 3 miR1-binding residues on the C-terminus of Kir2.1. Mechanistically, miR1 binds to the pore-facing G-loop of Kir2.1 through the core sequence AAGAAG, which is outside its RNA interference seed region. This biophysical modulation is involved in the dysregulation of gain-of-function Kir2.1-M301K mutation in short QT or atrial fibrillation. We found that an arrhythmia-associated human single nucleotide polymorphism of miR1 (hSNP14A/G) specifically disrupts the biophysical modulation while retaining the RNA interference function. It is remarkable that miR1 but not hSNP14A/G relieved the hyperpolarized resting membrane potential in miR1-deficient cardiomyocytes, improved the conduction velocity, and eliminated the high inducibility of arrhythmia in miR1-deficient hearts ex vivo. CONCLUSIONS Our study reveals a novel evolutionarily conserved biophysical action of endogenous miRs in modulating cardiac electrophysiology. Our discovery of miRs' biophysical modulation provides a more comprehensive understanding of ion channel dysregulation and may provide new insights into the pathogenesis of cardiac arrhythmias.
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Affiliation(s)
- Dandan Yang
- The Dorothy M. Davis Heart and Lung Research Institute, Frick Center for Heart Failure and Arrhythmia, Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Xiaoping Wan
- The Dorothy M. Davis Heart and Lung Research Institute, Frick Center for Heart Failure and Arrhythmia, Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Adrienne T. Dennis
- Department of Medicine, Heart and Vascular Research Center, The MetroHealth System, Case Western Reserve University, Cleveland, OH 44109, USA
| | - Emre Bektik
- Department of Medicine, Heart and Vascular Research Center, The MetroHealth System, Case Western Reserve University, Cleveland, OH 44109, USA
| | - Zhihua Wang
- Fuwai Hospital Chinese Academy of Medical Sciences, Shenzhen, Shenzhen, China
| | - Mauricio G.S. Costa
- Institute of Mineralogy, Materials Physics and Cosmochemistry, UMR 7590, Sorbonne Université, CNRS, MNHN, Paris F-75005, France
- Oswaldo Cruz Foundation, Scientific Computing Program, Vice Presidency of Education, Information and Communication, Rio de Janeiro, Brazil
| | - Charline Fagnen
- Institute of Mineralogy, Materials Physics and Cosmochemistry, UMR 7590, Sorbonne Université, CNRS, MNHN, Paris F-75005, France
| | - Catherine Vénien-Bryan
- Institute of Mineralogy, Materials Physics and Cosmochemistry, UMR 7590, Sorbonne Université, CNRS, MNHN, Paris F-75005, France
| | - Xianyao Xu
- The Dorothy M. Davis Heart and Lung Research Institute, Frick Center for Heart Failure and Arrhythmia, Departments of Biomedical Engineering and Internal Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Daniel H. Gratz
- The Dorothy M. Davis Heart and Lung Research Institute, Frick Center for Heart Failure and Arrhythmia, Departments of Biomedical Engineering and Internal Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Thomas J. Hund
- The Dorothy M. Davis Heart and Lung Research Institute, Frick Center for Heart Failure and Arrhythmia, Departments of Biomedical Engineering and Internal Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Peter J. Mohler
- The Dorothy M. Davis Heart and Lung Research Institute, Frick Center for Heart Failure and Arrhythmia, Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Kenneth R. Laurita
- Department of Medicine, Heart and Vascular Research Center, The MetroHealth System, Case Western Reserve University, Cleveland, OH 44109, USA
| | - Isabelle Deschênes
- The Dorothy M. Davis Heart and Lung Research Institute, Frick Center for Heart Failure and Arrhythmia, Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Ji-Dong Fu
- The Dorothy M. Davis Heart and Lung Research Institute, Frick Center for Heart Failure and Arrhythmia, Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH 43210, USA
- Department of Medicine, Heart and Vascular Research Center, The MetroHealth System, Case Western Reserve University, Cleveland, OH 44109, USA
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Iacobas S, Amuzescu B, Iacobas DA. Transcriptomic uniqueness and commonality of the ion channels and transporters in the four heart chambers. Sci Rep 2021; 11:2743. [PMID: 33531573 PMCID: PMC7854717 DOI: 10.1038/s41598-021-82383-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 01/03/2021] [Indexed: 02/07/2023] Open
Abstract
Myocardium transcriptomes of left and right atria and ventricles from four adult male C57Bl/6j mice were profiled with Agilent microarrays to identify the differences responsible for the distinct functional roles of the four heart chambers. Female mice were not investigated owing to their transcriptome dependence on the estrous cycle phase. Out of the quantified 16,886 unigenes, 15.76% on the left side and 16.5% on the right side exhibited differential expression between the atrium and the ventricle, while 5.8% of genes were differently expressed between the two atria and only 1.2% between the two ventricles. The study revealed also chamber differences in gene expression control and coordination. We analyzed ion channels and transporters, and genes within the cardiac muscle contraction, oxidative phosphorylation, glycolysis/gluconeogenesis, calcium and adrenergic signaling pathways. Interestingly, while expression of Ank2 oscillates in phase with all 27 quantified binding partners in the left ventricle, the percentage of in-phase oscillating partners of Ank2 is 15% and 37% in the left and right atria and 74% in the right ventricle. The analysis indicated high interventricular synchrony of the ion channels expressions and the substantially lower synchrony between the two atria and between the atrium and the ventricle from the same side.
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Affiliation(s)
- Sanda Iacobas
- Department of Pathology, New York Medical College, Valhalla, NY, 10595, USA
| | - Bogdan Amuzescu
- Department Biophysics and Physiology, Faculty of Biology, University of Bucharest, Bucharest, Romania
| | - Dumitru A Iacobas
- Personalized Genomics Laboratory, Center for Computational Systems Biology, Roy G. Perry College of Engineering, Prairie View A&M University, Prairie View, TX, 77446, USA. .,DP Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, 10461, USA.
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Luo T, Li L, Peng Y, Xie R, Yan N, Fan H, Zhang Q. The MORN domain of Junctophilin2 regulates functional interactions with small-conductance Ca 2+ -activated potassium channel subtype2 (SK2). Biofactors 2021; 47:69-79. [PMID: 31904168 DOI: 10.1002/biof.1608] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 12/17/2019] [Indexed: 01/15/2023]
Abstract
Small-conductance Ca2+ -activated K+ channel subtype2 (SK2) are stable macromolecular complexes that regulate myocardial excitability and Ca2+ homeostasis. Junctophilin-2 (JP2) is a membrane-binding protein, which provides functional crosstalk by physically linking with the cell-surface and intracellular ion channels. We previously demonstrated that the MORN domain of JP2 interacts with SK2 channels. However, the roles of the JP2 MORN domain in regulating the precise subcellular localization and molecular modulation of SK2 have not yet been incompletely understood. In the present study, in vitro and in vivo assays were used to confirm the physical interactions between the SK2 channel and JP2 in H9c2 and HEK293 cells, with a concentration on the association between the C-terminus of SK2 channels and the MORN domain of JP2. Furthermore, the membrane expression of SK2 were found to be significantly impaired by the mutation or knockdown of JP2. Using immunofluorescence staining along with Golgi/early endosome markers, we studied the mechanisms of JP2-regulated SK2 membrane trafficking, which indicates that the JP2 MORN domain is probably necessary for the retrograde trafficking of SK2 channels. The functional study demonstrates that whole cell SK2 current densities recorded from the HEK293 cells co-expressing the JP2-MORN domain with SK2 were significantly augmented, compared with cells expressing SK2 alone. Our findings suggest that the MORN domain of JP2 directly modulates SK2 channel current amplitude and trafficking, through its interaction with an overlapping region of the JP2 MORN domain on the SK2 C-terminus.
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Affiliation(s)
- Tianxia Luo
- Department of Physiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Liren Li
- Department of Physiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Yanghao Peng
- Department of Physiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Rongrong Xie
- Department of Physiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Ningning Yan
- Department of Physiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Hongkun Fan
- Department of Physiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Qian Zhang
- Department of Physiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
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Turan NN, Moshal KS, Roder K, Baggett BC, Kabakov AY, Dhakal S, Teramoto R, Chiang DYE, Zhong M, Xie A, Lu Y, Dudley SC, MacRae CA, Karma A, Koren G. The endosomal trafficking regulator LITAF controls the cardiac Nav1.5 channel via the ubiquitin ligase NEDD4-2. J Biol Chem 2020; 295:18148-18159. [PMID: 33093176 PMCID: PMC7939464 DOI: 10.1074/jbc.ra120.015216] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 10/20/2020] [Indexed: 01/14/2023] Open
Abstract
The QT interval is a recording of cardiac electrical activity. Previous genome-wide association studies identified genetic variants that modify the QT interval upstream of LITAF (lipopolysaccharide-induced tumor necrosis factor-α factor), a protein encoding a regulator of endosomal trafficking. However, it was not clear how LITAF might impact cardiac excitation. We investigated the effect of LITAF on the voltage-gated sodium channel Nav1.5, which is critical for cardiac depolarization. We show that overexpressed LITAF resulted in a significant increase in the density of Nav1.5-generated voltage-gated sodium current INa and Nav1.5 surface protein levels in rabbit cardiomyocytes and in HEK cells stably expressing Nav1.5. Proximity ligation assays showed co-localization of endogenous LITAF and Nav1.5 in cardiomyocytes, whereas co-immunoprecipitations confirmed they are in the same complex when overexpressed in HEK cells. In vitro data suggest that LITAF interacts with the ubiquitin ligase NEDD4-2, a regulator of Nav1.5. LITAF overexpression down-regulated NEDD4-2 in cardiomyocytes and HEK cells. In HEK cells, LITAF increased ubiquitination and proteasomal degradation of co-expressed NEDD4-2 and significantly blunted the negative effect of NEDD4-2 on INa We conclude that LITAF controls cardiac excitability by promoting degradation of NEDD4-2, which is essential for removal of surface Nav1.5. LITAF-knockout zebrafish showed increased variation in and a nonsignificant 15% prolongation of action potential duration. Computer simulations using a rabbit-cardiomyocyte model demonstrated that changes in Ca2+ and Na+ homeostasis are responsible for the surprisingly modest action potential duration shortening. These computational data thus corroborate findings from several genome-wide association studies that associated LITAF with QT interval variation.
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Affiliation(s)
- Nilüfer N Turan
- Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Karni S Moshal
- Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Karim Roder
- Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Brett C Baggett
- Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Anatoli Y Kabakov
- Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Saroj Dhakal
- Physics Department and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, Massachusetts, USA
| | - Ryota Teramoto
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - David Yi-Eng Chiang
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Mingwang Zhong
- Physics Department and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, Massachusetts, USA
| | - An Xie
- Cardiovascular Division, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Yichun Lu
- Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Samuel C Dudley
- Cardiovascular Division, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Calum A MacRae
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Alain Karma
- Physics Department and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, Massachusetts, USA
| | - Gideon Koren
- Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA.
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11
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Chang N, Gao J, Niu L, Hou Y, Wang X, Jiang M, Bai G. Integrated artificial neural network analysis and functional cell based affinity mass spectrometry for screening a bifunctional activator of Ca2+ and β2AR in aconite. J Pharm Biomed Anal 2020; 190:113506. [DOI: 10.1016/j.jpba.2020.113506] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 07/24/2020] [Accepted: 07/24/2020] [Indexed: 12/20/2022]
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12
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Baratchi S, Zaldivia MTK, Wallert M, Loseff-Silver J, Al-Aryahi S, Zamani J, Thurgood P, Salim A, Htun NM, Stub D, Vahidi P, Duffy SJ, Walton A, Nguyen TH, Jaworowski A, Khoshmanesh K, Peter K. Transcatheter Aortic Valve Implantation Represents an Anti-Inflammatory Therapy Via Reduction of Shear Stress-Induced, Piezo-1-Mediated Monocyte Activation. Circulation 2020; 142:1092-1105. [PMID: 32697107 DOI: 10.1161/circulationaha.120.045536] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Aortic valve stenosis is an increasingly prevalent degenerative and inflammatory disease. Transcatheter aortic valve implantation (TAVI) has revolutionized its treatment, thereby avoiding its life-threatening/disabling consequences. Whether aortic valve stenosis is accelerated by inflammation and whether it is itself a cause of inflammation are unclear. We hypothesized that the large shear forces exerted on circulating cells, particularly on the largest circulating cells, monocytes, while passing through stenotic aortic valves result in proinflammatory effects that are resolved with TAVI. METHODS TAVI provides a unique opportunity to compare the activation status of monocytes under high shear stress (before TAVI) and under low shear stress (after TAVI). The activation status of monocytes was determined with a single-chain antibody, MAN-1, which is specific for the activated β2-integrin Mac-1. Monocyte function was further characterized by the adhesion of myocytes to stimulated endothelial cells, phagocytic activity, uptake of oxidized low-density lipoprotein, and cytokine expression. In addition, we designed a microfluidic system to recapitulate the shear rate conditions before and after TAVI. We used this tool in combination with functional assays, Ca2+ imaging, siRNA gene silencing, and pharmacological agonists and antagonists to identify the key mechanoreceptor mediating the shear stress sensitivity of monocytes. Last, we stained for monocytes in explanted stenotic aortic human valves. RESULTS The resolution of high shear stress through TAVI reduces Mac-1 activation, cellular adhesion, phagocytosis, oxidized low-density lipoprotein uptake, and expression of inflammatory markers in monocytes and plasma. Using microfluidics and pharmacological and genetic studies, we could recapitulate high shear stress effects on isolated human monocytes under highly controlled conditions, showing that shear stress-dependent calcium influx and monocyte adhesion are mediated by the mechanosensitive ion channel Piezo-1. We also demonstrate that the expression of this receptor is shear stress dependent and downregulated in patients receiving TAVI. Last, we show monocyte accumulation at the aortic side of leaflets of explanted aortic valves. CONCLUSIONS We demonstrate that high shear stress, as present in patients with aortic valve stenosis, activates multiple monocyte functions, and we identify Piezo-1 as the mainly responsible mechanoreceptor, representing a potentially druggable target. We demonstrate an anti-inflammatory effect and therefore a novel therapeutic benefit of TAVI.
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Affiliation(s)
- Sara Baratchi
- School of Health and Biomedical Sciences (S.B., S.A.-A., P.V., A.J., K.P.), RMIT University, Melbourne, Victoria, Australia
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia (S.B., M.T.K.J., M.W., J.L.-S., A.S., N.M.H., D.S., K.P.)
| | - Maria T K Zaldivia
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia (S.B., M.T.K.J., M.W., J.L.-S., A.S., N.M.H., D.S., K.P.)
| | - Maria Wallert
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia (S.B., M.T.K.J., M.W., J.L.-S., A.S., N.M.H., D.S., K.P.)
| | - Julia Loseff-Silver
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia (S.B., M.T.K.J., M.W., J.L.-S., A.S., N.M.H., D.S., K.P.)
| | - Sefaa Al-Aryahi
- School of Health and Biomedical Sciences (S.B., S.A.-A., P.V., A.J., K.P.), RMIT University, Melbourne, Victoria, Australia
| | - Jalal Zamani
- Department of Cardiology, Alfred Hospital, Melbourne, Victoria, Australia (J.Z., N.M.H., D.S., S.J.D., A.W., K.P.)
| | - Peter Thurgood
- School of Engineering (P.T., K.K.), RMIT University, Melbourne, Victoria, Australia
| | - Agus Salim
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia (S.B., M.T.K.J., M.W., J.L.-S., A.S., N.M.H., D.S., K.P.)
- Department of Mathematics and Statistics, La Trobe University, Melbourne, Victoria, Australia (A.S.)
| | - Nay M Htun
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia (S.B., M.T.K.J., M.W., J.L.-S., A.S., N.M.H., D.S., K.P.)
- Department of Cardiology, Alfred Hospital, Melbourne, Victoria, Australia (J.Z., N.M.H., D.S., S.J.D., A.W., K.P.)
| | - Dion Stub
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia (S.B., M.T.K.J., M.W., J.L.-S., A.S., N.M.H., D.S., K.P.)
- Department of Cardiology, Alfred Hospital, Melbourne, Victoria, Australia (J.Z., N.M.H., D.S., S.J.D., A.W., K.P.)
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia (D.S.)
| | - Parisa Vahidi
- School of Health and Biomedical Sciences (S.B., S.A.-A., P.V., A.J., K.P.), RMIT University, Melbourne, Victoria, Australia
| | - Stephen J Duffy
- Department of Cardiology, Alfred Hospital, Melbourne, Victoria, Australia (J.Z., N.M.H., D.S., S.J.D., A.W., K.P.)
| | - Antony Walton
- Department of Cardiology, Alfred Hospital, Melbourne, Victoria, Australia (J.Z., N.M.H., D.S., S.J.D., A.W., K.P.)
| | - Thanh Ha Nguyen
- Cardiology Department, Queen Elizabeth Hospital, University of Adelaide, Woodville, South Australia, Australia (T.H.N.)
| | - Anthony Jaworowski
- School of Health and Biomedical Sciences (S.B., S.A.-A., P.V., A.J., K.P.), RMIT University, Melbourne, Victoria, Australia
| | | | - Karlheinz Peter
- School of Health and Biomedical Sciences (S.B., S.A.-A., P.V., A.J., K.P.), RMIT University, Melbourne, Victoria, Australia
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia (S.B., M.T.K.J., M.W., J.L.-S., A.S., N.M.H., D.S., K.P.)
- Department of Cardiology, Alfred Hospital, Melbourne, Victoria, Australia (J.Z., N.M.H., D.S., S.J.D., A.W., K.P.)
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Tinaquero D, Crespo-García T, Utrilla RG, Nieto-Marín P, González-Guerra A, Rubio-Alarcón M, Cámara-Checa A, Dago M, Matamoros M, Pérez-Hernández M, Tamargo M, Cebrián J, Jalife J, Tamargo J, Bernal JA, Caballero R, Delpón E. The p.P888L SAP97 polymorphism increases the transient outward current (I to,f) and abbreviates the action potential duration and the QT interval. Sci Rep 2020; 10:10707. [PMID: 32612162 PMCID: PMC7329876 DOI: 10.1038/s41598-020-67109-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Accepted: 06/01/2020] [Indexed: 11/09/2022] Open
Abstract
Synapse-Associated Protein 97 (SAP97) is an anchoring protein that in cardiomyocytes targets to the membrane and regulates Na+ and K+ channels. Here we compared the electrophysiological effects of native (WT) and p.P888L SAP97, a common polymorphism. Currents were recorded in cardiomyocytes from mice trans-expressing human WT or p.P888L SAP97 and in Chinese hamster ovary (CHO)-transfected cells. The duration of the action potentials and the QT interval were significantly shorter in p.P888L-SAP97 than in WT-SAP97 mice. Compared to WT, p.P888L SAP97 significantly increased the charge of the Ca-independent transient outward (Ito,f) current in cardiomyocytes and the charge crossing Kv4.3 channels in CHO cells by slowing Kv4.3 inactivation kinetics. Silencing or inhibiting Ca/calmodulin kinase II (CaMKII) abolished the p.P888L-induced Kv4.3 charge increase, which was also precluded in channels (p.S550A Kv4.3) in which the CaMKII-phosphorylation is prevented. Computational protein-protein docking predicted that p.P888L SAP97 is more likely to form a complex with CaMKII than WT. The Na+ current and the current generated by Kv1.5 channels increased similarly in WT-SAP97 and p.P888L-SAP97 cardiomyocytes, while the inward rectifier current increased in WT-SAP97 but not in p.P888L-SAP97 cardiomyocytes. The p.P888L SAP97 polymorphism increases the Ito,f, a CaMKII-dependent effect that may increase the risk of arrhythmias.
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Affiliation(s)
- David Tinaquero
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, Madrid, Spain
| | - Teresa Crespo-García
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, Madrid, Spain
| | - Raquel G Utrilla
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, Madrid, Spain
| | - Paloma Nieto-Marín
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, Madrid, Spain
| | | | - Marcos Rubio-Alarcón
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, Madrid, Spain
| | - Anabel Cámara-Checa
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, Madrid, Spain
| | - María Dago
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, Madrid, Spain
| | - Marcos Matamoros
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, Madrid, Spain
| | - Marta Pérez-Hernández
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, Madrid, Spain
| | - María Tamargo
- Cardiology Department, Hospital General Universitario Gregorio Marañón, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, Madrid, Spain
| | - Jorge Cebrián
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, Madrid, Spain
| | - José Jalife
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain.,Department of Internal Medicine/Cardiovascular Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Juan Tamargo
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, Madrid, Spain
| | | | - Ricardo Caballero
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, Madrid, Spain.
| | - Eva Delpón
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, Madrid, Spain
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Liu Z, Jia Y, Song L, Tian Y, Zhang P, Zhang P, Cao Z, Ma J. Antiarrhythmic effect of crotonoside by regulating sodium and calcium channels in rabbit ventricular myocytes. Life Sci 2020; 244:117333. [PMID: 31962132 DOI: 10.1016/j.lfs.2020.117333] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 12/30/2019] [Accepted: 01/13/2020] [Indexed: 12/14/2022]
Abstract
AIMS Detect the antiarrhythmic effect of crotonoside (Cro). MAIN METHODS We used whole-cell patch-clamp techniques to detect the effects of Cro on action potentials (APs) and transmembrane ion currents in isolated rabbit left ventricular myocytes. We also verified the effect of Cro on ventricular arrhythmias caused by aconitine in vivo. KEY FINDINGS Cro reduced the maximum depolarization velocity (Vmax) of APs and shortened the action potential duration (APD) in a concentration-dependent manner, but it had no significant effect on the resting membrane potential (RMP) or action potential amplitude (APA). It also inhibited the peak sodium current (INa) and L-type calcium current (ICaL) in a concentration-dependent manner with half-maximal inhibitory concentrations (IC50) of 192 μmol/L and 159 μmol/L, respectively. However, Cro had no significant effects on the inward rectifier potassium current (IK1) or rapidly activating delayed rectifier potassium current (IKr). Sea anemone toxin II (ATX II) increased the late sodium current (INaL), but Cro abolished this effect. Moreover, Cro significantly abolished ATX II-induced early afterdepolarizations (EADs) and high extracellular Ca2+ concentration (3.6 mmol/L)-induced delayed afterdepolarizations (DADs). We also verified that Cro effectively delayed the onset time and reduced the incidence of ventricular arrhythmias caused by aconitine in vivo. SIGNIFICANCE These results revealed that Cro effectively inhibits INa, INaL, and ICaL in ventricular myocytes. Cro has antiarrhythmic potential and thus deserves further study.
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Affiliation(s)
- Zhipei Liu
- Cardio-Electrophysiological Research Laboratory, Medical College of Wuhan University of Science and Technology, Wuhan 430065, China; Hubei Province Key Laboratory of Occupational Hazard Identification and Control, Medical College of Wuhan University of Science and Technology, Wuhan 430065, China
| | - Yuzhong Jia
- Cardio-Electrophysiological Research Laboratory, Medical College of Wuhan University of Science and Technology, Wuhan 430065, China
| | - Lv Song
- Cardio-Electrophysiological Research Laboratory, Medical College of Wuhan University of Science and Technology, Wuhan 430065, China
| | - Youjia Tian
- Cardio-Electrophysiological Research Laboratory, Medical College of Wuhan University of Science and Technology, Wuhan 430065, China
| | - Peipei Zhang
- Cardio-Electrophysiological Research Laboratory, Medical College of Wuhan University of Science and Technology, Wuhan 430065, China; Hubei Province Key Laboratory of Occupational Hazard Identification and Control, Medical College of Wuhan University of Science and Technology, Wuhan 430065, China
| | - Peihua Zhang
- Cardio-Electrophysiological Research Laboratory, Medical College of Wuhan University of Science and Technology, Wuhan 430065, China
| | - Zhenzhen Cao
- Cardio-Electrophysiological Research Laboratory, Medical College of Wuhan University of Science and Technology, Wuhan 430065, China
| | - Jihua Ma
- Cardio-Electrophysiological Research Laboratory, Medical College of Wuhan University of Science and Technology, Wuhan 430065, China; Hubei Province Key Laboratory of Occupational Hazard Identification and Control, Medical College of Wuhan University of Science and Technology, Wuhan 430065, China.
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15
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Geng L, Wang S, Zhang F, Xiong K, Huang J, Zhao T, Shi D, Lv F, Li L, Liang D, Cui Y, Liu Y, Xie D, Chen YH. SNX17 (Sorting Nexin 17) Mediates Atrial Fibrillation Onset Through Endocytic Trafficking of the Kv1.5 (Potassium Voltage-Gated Channel Subfamily A Member 5) Channel. Circ Arrhythm Electrophysiol 2020; 12:e007097. [PMID: 30939909 DOI: 10.1161/circep.118.007097] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND Kv1.5 (Potassium voltage-gated channel subfamily A member 5) has been regarded as a promising target of interventions for atrial fibrillation (AF). SNX17 (sorting nexin 17), a member of the SNXs (sorting nexin family), regulates the intracellular trafficking of membrane proteins through its FERM (four-point-one, ezrin, radixin, moesin) domain. However, whether SNX17 regulates the trafficking process of Kv1.5 remains unknown. METHODS A SNX17 knockout rat line was generated to test the role of SNX17 in atrial electrophysiology. The protein expression of SNX17 and membrane ion channels was detected by Western blotting. Electrophysiology changes in the atrial tissue and myocytes were analyzed by optical mapping and patch clamp, respectively. Acetylcholine and electrical stimulation were used to induce AF, and ECG recording was adopted to assess the influence of SNX17 deficiency on AF susceptibility. The spatial relationship between Kv1.5 and SNX17 was evaluated by immunostaining and confocal scanning, and the functional region of SNX17 regulating Kv1.5 trafficking was identified using plasmids with truncated SNX17 domains. RESULTS Embryonic death occurred in homozygous SNX17 knockout rats. SNX17 heterozygous rats survived, and the level of the SNX17 protein in the atrium was decreased by ≈50%. SNX17 deficiency increased the membrane expression of Kv1.5 and atria-specific ultrarapid delayed rectifier outward potassium current ( IKur) density, resulting in a shortened action potential duration, and eventually contributing to AF susceptibility. Mechanistically, SNX17 facilitated the endocytic sorting of Kv1.5 from the plasma membrane to early endosomes via the FERM domain. CONCLUSIONS SNX17 mediates susceptibility to AF by regulating endocytic sorting of the Kv1.5 channel through the FERM domain. SNX17 could be a potential target for the development of new drugs for AF.
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Affiliation(s)
- Li Geng
- Key Laboratory of Arrhythmias of the Ministry of Education of East Hospital (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China.,Institute of Medical Genetics (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., L.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China
| | - Shuo Wang
- Key Laboratory of Arrhythmias of the Ministry of Education of East Hospital (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China.,Institute of Medical Genetics (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., L.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China
| | - Fulei Zhang
- Key Laboratory of Arrhythmias of the Ministry of Education of East Hospital (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China.,Institute of Medical Genetics (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., L.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China
| | - Ke Xiong
- Key Laboratory of Arrhythmias of the Ministry of Education of East Hospital (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China.,Institute of Medical Genetics (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., L.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China
| | - Jian Huang
- Key Laboratory of Arrhythmias of the Ministry of Education of East Hospital (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China.,Institute of Medical Genetics (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., L.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China
| | - Tingting Zhao
- Key Laboratory of Arrhythmias of the Ministry of Education of East Hospital (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China.,Institute of Medical Genetics (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., L.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China
| | - Dan Shi
- Key Laboratory of Arrhythmias of the Ministry of Education of East Hospital (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China.,Institute of Medical Genetics (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., L.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China
| | - Fei Lv
- Key Laboratory of Arrhythmias of the Ministry of Education of East Hospital (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China.,Institute of Medical Genetics (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., L.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China
| | - Li Li
- Institute of Medical Genetics (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., L.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China
| | - Dandan Liang
- Key Laboratory of Arrhythmias of the Ministry of Education of East Hospital (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China.,Institute of Medical Genetics (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., L.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China
| | - Yingyu Cui
- Key Laboratory of Arrhythmias of the Ministry of Education of East Hospital (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China.,Institute of Medical Genetics (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., L.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China
| | - Yi Liu
- Key Laboratory of Arrhythmias of the Ministry of Education of East Hospital (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China.,Institute of Medical Genetics (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., L.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China
| | - Duanyang Xie
- Key Laboratory of Arrhythmias of the Ministry of Education of East Hospital (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China.,Institute of Medical Genetics (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., L.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China.,School of Life Science and Technology (D.X.), Tongji University, Shanghai, China
| | - Yi-Han Chen
- Key Laboratory of Arrhythmias of the Ministry of Education of East Hospital (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China.,Institute of Medical Genetics (L.G., S.W., F.Z., K.X., J.H., T.Z., D.S., F.L., L.L., D.L., Y.C., Y.L., D.X., Y.-H.C.), Tongji University, Shanghai, China
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16
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Enhanced Activity by NKCC1 and Slc26a6 Mediates Acidic pH and Cl - Movement after Cardioplegia-Induced Arrest of db/db Diabetic Heart. Mediators Inflamm 2019; 2019:7583760. [PMID: 31582903 PMCID: PMC6754936 DOI: 10.1155/2019/7583760] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 07/26/2019] [Accepted: 08/13/2019] [Indexed: 01/22/2023] Open
Abstract
Diabetic heart dysfunctions during cardiac surgeries have revealed several clinical problems associated with ion imbalance. However, the mechanism of ion imbalance mediated by cardioplegia and a diabetic heart is largely unclear. We hypothesized that ion transporters might be regulated differently in the diabetic heart and that the differentially regulated ion transporters may involve in ion imbalance of the diabetic heart after cardioplegic arrest. In this study, we modified the Langendorff-free cardioplegia method and identified the involved ion transporters after cardioplegia-induced arrest between wild type and db/db heart. Enhanced expression of Na+-K+-2Cl− cotransporter 1 (NKCC1) was observed in the db/db heart compared to the wild type heart. Enhanced NKCC1 activity was observed in the left ventricle of db/db mice compared to that of wild type after cardioplegia-induced arrest. The expression and activity of Slc26a6, a dominant Cl−/HCO3− exchanger in cardiac tissues, were enhanced in left ventricle strips of db/db mice compared to that of wild type. The Cl− transporting activity in left ventricle strips of db/db mice was dramatically increased as compared to that of wild type. Interestingly, expression of Slc26a6, as well as carbonic anhydrase IV as a supportive enzyme of Slc26a6, was increased in db/db cardiac strips compared to wild type cardiac strips. Thus, the enhanced Cl− transporting activity and expression by NKCC1 and Slc26a6 in db/db cardiac tissues after cardioplegia-induced arrest provide greater insight into enhanced acidosis and Cl− movement-mediated db/db heart dysfunction. Thus, we suggested that enhanced Cl− influx and HCO3− efflux through NKCC1 and Slc26a6 offer more acidic circumstances in the diabetic heart after cardioplegic arrest. These transporters should be considered as potential therapeutic targets to develop the next generation of cardioplegia solution for protection against ischemia-reperfusion injury in diabetic hearts.
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Sengupta S, Rothenberg KE, Li H, Hoffman BD, Bursac N. Altering integrin engagement regulates membrane localization of K ir2.1 channels. J Cell Sci 2019; 132:jcs225383. [PMID: 31391240 PMCID: PMC6771140 DOI: 10.1242/jcs.225383] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 07/31/2019] [Indexed: 12/26/2022] Open
Abstract
How ion channels localize and distribute on the cell membrane remains incompletely understood. We show that interventions that vary cell adhesion proteins and cell size also affect the membrane current density of inward-rectifier K+ channels (Kir2.1; encoded by KCNJ2) and profoundly alter the action potential shape of excitable cells. By using micropatterning to manipulate the localization and size of focal adhesions (FAs) in single HEK293 cells engineered to stably express Kir2.1 channels or in neonatal rat cardiomyocytes, we establish a robust linear correlation between FA coverage and the amplitude of Kir2.1 current at both the local and whole-cell levels. Confocal microscopy showed that Kir2.1 channels accumulate in membrane proximal to FAs. Selective pharmacological inhibition of key mediators of protein trafficking and the spatially dependent alterations in the dynamics of Kir2.1 fluorescent recovery after photobleaching revealed that the Kir2.1 channels are transported to the cell membrane uniformly, but are preferentially internalized by endocytosis at sites that are distal from FAs. Based on these results, we propose adhesion-regulated membrane localization of ion channels as a fundamental mechanism of controlling cellular electrophysiology via mechanochemical signals, independent of the direct ion channel mechanogating.
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Affiliation(s)
- Swarnali Sengupta
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | | | - Hanjun Li
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Brenton D Hoffman
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Nenad Bursac
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
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Haustrate A, Hantute-Ghesquier A, Prevarskaya N, Lehen'kyi V. Monoclonal Antibodies Targeting Ion Channels and Their Therapeutic Potential. Front Pharmacol 2019; 10:606. [PMID: 31231216 PMCID: PMC6561378 DOI: 10.3389/fphar.2019.00606] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 05/14/2019] [Indexed: 12/27/2022] Open
Abstract
Monoclonal antibodies (mAbs) represent a rapidly growing pharmaceutical class of protein drugs that becomes an important part of the precision therapy. mAbs are characterized by their high specificity and affinity for the target antigen, which is mostly present on the cell surface. Ion channels are a large family of transmembrane proteins that control ion transport across the cell membrane. They are involved in almost all biological processes in both health and disease and are widely considered as prospective targets. However, no antibody-based drug targeting ion channel has been developed so far that has progressed to clinical use. Thus, we provide a comprehensive review of the elaborated mAbs against ion channels, describe their mechanisms of action, and discuss their therapeutic potential.
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Affiliation(s)
- Aurélien Haustrate
- Laboratory of Cell Physiology, INSERM U1003, Laboratory of Excellence Ion Channel Science and Therapeutics, Department of Biology, Faculty of Science and Technologies, University of Lille, Villeneuve d'Ascq, France
| | - Aline Hantute-Ghesquier
- Laboratory of Cell Physiology, INSERM U1003, Laboratory of Excellence Ion Channel Science and Therapeutics, Department of Biology, Faculty of Science and Technologies, University of Lille, Villeneuve d'Ascq, France
| | - Natalia Prevarskaya
- Laboratory of Cell Physiology, INSERM U1003, Laboratory of Excellence Ion Channel Science and Therapeutics, Department of Biology, Faculty of Science and Technologies, University of Lille, Villeneuve d'Ascq, France
| | - V'yacheslav Lehen'kyi
- Laboratory of Cell Physiology, INSERM U1003, Laboratory of Excellence Ion Channel Science and Therapeutics, Department of Biology, Faculty of Science and Technologies, University of Lille, Villeneuve d'Ascq, France.,FONDATION ARC, Villejuif, France
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Bruyneel AAN, McKeithan WL, Feyen DAM, Mercola M. Using iPSC Models to Probe Regulation of Cardiac Ion Channel Function. Curr Cardiol Rep 2018; 20:57. [DOI: 10.1007/s11886-018-1000-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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20
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Portero V, Wilders R, Casini S, Charpentier F, Verkerk AO, Remme CA. K V4.3 Expression Modulates Na V1.5 Sodium Current. Front Physiol 2018; 9:178. [PMID: 29593552 PMCID: PMC5857579 DOI: 10.3389/fphys.2018.00178] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 02/20/2018] [Indexed: 01/14/2023] Open
Abstract
In cardiomyocytes, the voltage-gated transient outward potassium current (Ito) is responsible for the phase-1 repolarization of the action potential (AP). Gain-of-function mutations in KCND3, the gene encoding the Ito carrying KV4.3 channel, have been associated with Brugada syndrome (BrS). While the role of Ito in the pro-arrhythmic mechanism of BrS has been debated, recent studies have suggested that an increased Ito may directly affect cardiac conduction. However, the effects of an increased Ito on AP upstroke velocity or sodium current at the cellular level remain unknown. We here investigated the consequences of KV4.3 overexpression on NaV1.5 current and consequent sodium channel availability. We found that overexpression of KV4.3 protein in HEK293 cells stably expressing NaV1.5 (HEK293-NaV1.5 cells) significantly reduced NaV1.5 current density without affecting its kinetic properties. In addition, KV4.3 overexpression decreased AP upstroke velocity in HEK293-NaV1.5 cells, as measured with the alternating voltage/current clamp technique. These effects of KV4.3 could not be explained by alterations in total NaV1.5 protein expression. Using computer simulations employing a multicellular in silico model, we furthermore demonstrate that the experimentally observed increase in KV4.3 current and concurrent decrease in NaV1.5 current may result in a loss of conduction, underlining the potential functional relevance of our findings. This study gives the first proof of concept that KV4.3 directly impacts on NaV1.5 current. Future studies employing appropriate disease models should explore the potential electrophysiological implications in (patho)physiological conditions, including BrS associated with KCND3 gain-of-function mutations.
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Affiliation(s)
- Vincent Portero
- Department of Experimental Cardiology, Academic Medical Center, Amsterdam, Netherlands
| | - Ronald Wilders
- Department of Medical Biology, Academic Medical Center, Amsterdam, Netherlands
| | - Simona Casini
- Department of Experimental Cardiology, Academic Medical Center, Amsterdam, Netherlands
| | | | - Arie O Verkerk
- Department of Experimental Cardiology, Academic Medical Center, Amsterdam, Netherlands.,Department of Medical Biology, Academic Medical Center, Amsterdam, Netherlands
| | - Carol Ann Remme
- Department of Experimental Cardiology, Academic Medical Center, Amsterdam, Netherlands
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