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Wang XC, Zhou Y, Chen HX, Hou HT, He GW, Yang Q. ER stress modulates Kv1.5 channels via PERK branch in HL-1 atrial myocytes: Relevance to atrial arrhythmogenesis and the effect of tetramethylpyrazine. Heliyon 2024; 10:e37767. [PMID: 39318794 PMCID: PMC11420496 DOI: 10.1016/j.heliyon.2024.e37767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 09/05/2024] [Accepted: 09/09/2024] [Indexed: 09/26/2024] Open
Abstract
Endoplasmic reticulum (ER) stress is implicated in cardiac arrhythmia whereas the associated mechanisms remain inadequately understood. Kv1.5 channels are essential for atrial repolarization. Whether ER stress affects Kv1.5 channels is unknown. This study aimed to elucidate the response of Kv1.5 channels to ER stress by clarifying the unfolded protein response (UPR) branch responsible for the channel modulation. In addition, the effect of tetramethylpyrazine (TMP) on Kv1.5 channels was studied. Patch clamp and western-blot results revealed that exposure of HL-1 atrial myocytes to ER stress inducer tunicamycin upregulates Kv1.5 expression, increases Kv1.5 channel current (I Kur ) (14.91 ± 1.11 vs. 6.11 ± 1.31 pA/pF, P < 0.001), and shortened action potential duration (APD) (APD90: 82.79 ± 5.25 vs.121.11 ± 6.72 ms, P < 0.01), which could be reverted by ER stress inhibitors. Blockade of the PERK branch while not IRE1 and ATF6 branches of UPR downregulated Kv1.5 expression, accompanied by a decreased I Kur (9.03 ± 0.99 pA/pF) and a prolonged APD90 (113.69 ± 4.41 ms) (P < 0.01). PERK-mediated increases of Kv1.5 expression and I Kur were also observed in HL-1 cells incubated with thapsigargin. TMP suppressed the enhancement of I Kur (10.52 ± 0.97 vs. 17.52 ± 2.25 pA/pF, P < 0.05), prevented the shortening of APD (APD90: 110.16 ± 5.36 vs. 84.84 ± 4.58 ms, P < 0.05), and inhibited the upregulation of Kv1.5 triggered by ER stress. Our study suggests that ER stress induces upregulation and activation of Kv1.5 channels in atrial myocytes through the PERK branch of UPR. TMP prevents Kv1.5 upregulation/activation and the resultant APD shortening by inhibiting ER stress. These results may shed light on the mechanisms of atrial arrhythmogenesis and the antiarrhythmic effect of the traditional Chinese herb TMP.
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Affiliation(s)
- Xiang-Chong Wang
- Institute of Cardiovascular Diseases & Department of Cardiac Surgery, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College & Tianjin University, Tianjin, 300457, China
- Tianjin Key Laboratory of Molecular Regulation of Cardiovascular Diseases and Translational Medicine, Tianjin, China
- Department of Pharmacology, Hebei Higher Education Institute Applied Technology Research Center on TCM Formula Preparation, Hebei International Cooperation Center for Ion channel Function and Innovative Traditional Chinese Medicine, Hebei University of Chinese Medicine, Shijiazhuang, 050091, China
- School of Medicine, Nankai University, Tianjin, 300457, China
| | - Yang Zhou
- Institute of Cardiovascular Diseases & Department of Cardiac Surgery, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College & Tianjin University, Tianjin, 300457, China
- Tianjin Key Laboratory of Molecular Regulation of Cardiovascular Diseases and Translational Medicine, Tianjin, China
| | - Huan-Xin Chen
- Institute of Cardiovascular Diseases & Department of Cardiac Surgery, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College & Tianjin University, Tianjin, 300457, China
- Tianjin Key Laboratory of Molecular Regulation of Cardiovascular Diseases and Translational Medicine, Tianjin, China
| | - Hai-Tao Hou
- Institute of Cardiovascular Diseases & Department of Cardiac Surgery, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College & Tianjin University, Tianjin, 300457, China
- Tianjin Key Laboratory of Molecular Regulation of Cardiovascular Diseases and Translational Medicine, Tianjin, China
| | - Guo-Wei He
- Institute of Cardiovascular Diseases & Department of Cardiac Surgery, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College & Tianjin University, Tianjin, 300457, China
- Tianjin Key Laboratory of Molecular Regulation of Cardiovascular Diseases and Translational Medicine, Tianjin, China
| | - Qin Yang
- Institute of Cardiovascular Diseases & Department of Cardiac Surgery, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College & Tianjin University, Tianjin, 300457, China
- Tianjin Key Laboratory of Molecular Regulation of Cardiovascular Diseases and Translational Medicine, Tianjin, China
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Casado-Arroyo R, Bernardi M, Sabouret P, Franculli G, Tamargo J, Spadafora L, Lellouche N, Biondi-Zoccai G, Toth PP, Banach M. Investigative agents for atrial fibrillation: agonists and stimulants, progress and expectations. Expert Opin Investig Drugs 2024; 33:967-978. [PMID: 39096248 DOI: 10.1080/13543784.2024.2388583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2024] [Revised: 07/10/2024] [Accepted: 08/01/2024] [Indexed: 08/05/2024]
Abstract
INTRODUCTION Atrial fibrillation (AF) is the most common type of cardiac arrhythmia. Its prevalence has increased due to worldwide populations that are aging in combination with the growing incidence of risk factors associated. Recent advances in our understanding of AF pathophysiology and the identification of nodal players involved in AF-promoting atrial remodeling highlights potential opportunities for new therapeutic approaches. AREAS COVERED This detailed review summarizes recent developments in the field antiarrhythmic drugs in the field AF. EXPERT OPINION The current situation is far than optimal. Despite clear unmet needs in drug development in the field of AF treatment, the current development of new drugs is absent. The need for a molecule with absence of cardiac and non-cardiac toxicity in the short and long term is a limitation in the field. Improvement in the understanding of AF genetics, pathophysiology, molecular alterations, big data and artificial intelligence with the objective to provide a personalized AF treatment will be the cornerstone of AF treatment in the coming years.
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Affiliation(s)
- Ruben Casado-Arroyo
- Department of Cardiology, H.U.B.-Hôpital Erasme, Université Libre de Bruxelles, Brussels, Belgium
| | - Marco Bernardi
- Department of Clinical, Internal Medicine, Anesthesiology and Cardiovascular Sciences, Sapienza University of Rome, Rome, Italy
| | - Pierre Sabouret
- Heart Institute, ACTION Study Group-CHU Pitié-Salpétrière Paris, Paris, France
- Collège National des Cardiologues Français (CNCF), Paris, France
| | - Giuseppe Franculli
- Department of Clinical, Internal Medicine, Anesthesiology and Cardiovascular Sciences, Sapienza University of Rome, Rome, Italy
| | - Juan Tamargo
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense, Instituto De Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | - Luigi Spadafora
- Department of Clinical, Internal Medicine, Anesthesiology and Cardiovascular Sciences, Sapienza University of Rome, Rome, Italy
| | - Nicolas Lellouche
- Service de Cardiologie, AP-HP, University Hospital Henri Mondor, Créteil, France
| | - Giuseppe Biondi-Zoccai
- Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Latina, Italy
- Maria Cecilia Hospital, GVM Care & Research, Cotignola, Italy
| | - Peter P Toth
- CGH Medical Center, Sterling, IL, USA
- Cicarrone Center for the Prevention of Cardiovascular Disease, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Maciej Banach
- Department of Preventive Cardiology and Lipidology, Medical University of Lodz Lodz Poland, Lodz, Poland
- Department of Cardiology and Congenital Diseases of Adults, Polish Mother's Memorial Hospital Research Institute Lodz Poland, Lodz, Poland
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Botti S, Bartolucci C, Altomare C, Paci M, Barile L, Krause R, Pavarino LF, Severi S. A novel ionic model for matured and paced atrial-like human iPSC-CMs integrating I Kur and I KCa currents. Comput Biol Med 2024; 180:108899. [PMID: 39106668 DOI: 10.1016/j.compbiomed.2024.108899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 06/25/2024] [Accepted: 07/14/2024] [Indexed: 08/09/2024]
Abstract
This work introduces the first atrial-specific in-silico human induced pluripotent stem cells-derived cardiomyocytes (hiPSC-CMs) model, based on a set of phenotype-specific IKur,IKCa and IK1 membrane currents. This model is built on novel in-vitro experimental data recently published by some of the co-authors to simulate the paced action potential of matured atrial-like hiPSC-CMs. The model consists of a system of stiff ordinary differential equations depending on several parameters, which have been tuned by automatic optimization techniques to closely match selected experimental biomarkers. The new model effectively simulates the electronic in-vitro hiPSC-CMs maturation process, transitioning from an unstable depolarized membrane diastolic potential to a stable hyperpolarized resting potential, and exhibits spontaneous firing activity in unpaced conditions. Moreover, our model accurately reflects the experimental rate dependence data at different cycle length and demonstrates the expected response to a specific current blocker. This atrial-specific in-silico model provides a novel computational tool for electrophysiological studies of cardiac stem cells and their applications to drug evaluation and atrial fibrillation treatment.
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Affiliation(s)
- Sofia Botti
- Euler Institute, Faculty of Informatics, Università della Svizzera Italiana, Lugano, 6900, Switzerland; Department of Mathematics "Felice Casorati", University of Pavia, Pavia, 27100, Italy.
| | - Chiara Bartolucci
- Department of Electrical, Electronic, and Information Engineering "Guglielmo Marconi", University of Bologna, Cesena, 47521, Italy
| | - Claudia Altomare
- Cardiovascular Theranostics, Istituto Cardiocentro Ticino, Ente Ospedaliero Cantonale, Lugano, 6900, Switzerland; Laboratories for Translational Research, Ente Ospedaliero Cantonale, Bellinzona, 6500, Switzerland; Euler Institute, Faculty of Biomedical Sciences, Università della Svizzera Italiana, Lugano, 6900, Switzerland
| | - Michelangelo Paci
- Department of Electrical, Electronic, and Information Engineering "Guglielmo Marconi", University of Bologna, Cesena, 47521, Italy
| | - Lucio Barile
- Cardiovascular Theranostics, Istituto Cardiocentro Ticino, Ente Ospedaliero Cantonale, Lugano, 6900, Switzerland; Laboratories for Translational Research, Ente Ospedaliero Cantonale, Bellinzona, 6500, Switzerland; Euler Institute, Faculty of Biomedical Sciences, Università della Svizzera Italiana, Lugano, 6900, Switzerland
| | - Rolf Krause
- Euler Institute, Faculty of Informatics, Università della Svizzera Italiana, Lugano, 6900, Switzerland; Faculty of Mathematics and Informatics, UniDistance, Brig, 3900, Switzerland
| | - Luca Franco Pavarino
- Department of Mathematics "Felice Casorati", University of Pavia, Pavia, 27100, Italy
| | - Stefano Severi
- Department of Electrical, Electronic, and Information Engineering "Guglielmo Marconi", University of Bologna, Cesena, 47521, Italy
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Chakraborty A, Paynter A, Szendrey M, Cornwell JD, Li W, Guo J, Yang T, Du Y, Wang T, Zhang S. Ubiquitination is involved in PKC-mediated degradation of cell surface Kv1.5 channels. J Biol Chem 2024; 300:107483. [PMID: 38897569 PMCID: PMC11301065 DOI: 10.1016/j.jbc.2024.107483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 05/30/2024] [Accepted: 06/12/2024] [Indexed: 06/21/2024] Open
Abstract
The voltage-gated Kv1.5 potassium channel, conducting the ultra-rapid delayed rectifier K+ current (IKur) in human cells, plays important roles in the repolarization of atrial action potentials and regulation of the vascular tone. We previously reported that activation of protein kinase C (PKC) by phorbol 12-myristate 13-acetate (PMA) induces endocytic degradation of cell-surface Kv1.5 channels, and a point mutation removing the phosphorylation site, T15A, in the N terminus of Kv1.5 abolished the PMA-effect. In the present study, using mutagenesis, patch clamp recording, Western blot analysis, and immunocytochemical staining, we demonstrate that ubiquitination is involved in the PMA-mediated degradation of mature Kv1.5 channels. Since the expression of the Kv1.4 channel is unaffected by PMA treatment, we swapped the N- and/or C-termini between Kv1.5 and Kv1.4. We found that the N-terminus alone did not but both N- and C-termini of Kv1.5 did confer PMA sensitivity to mature Kv1.4 channels, suggesting the involvement of Kv1.5 C-terminus in the channel ubiquitination. Removal of each of the potential ubiquitination residue Lysine at position 536, 565, and 591 by Arginine substitution (K536R, K565R, and K591R) had little effect, but removal of all three Lysine residues with Arginine substitution (3K-R) partially reduced PMA-mediated Kv1.5 degradation. Furthermore, removing the cysteine residue at position 604 by Serine substitution (C604S) drastically reduced PMA-induced channel degradation. Removal of the three Lysines and Cys604 with a quadruple mutation (3K-R/C604S) or a truncation mutation (Δ536) completely abolished the PKC activation-mediated degradation of Kv1.5 channels. These results provide mechanistic insight into PKC activation-mediated Kv1.5 degradation.
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Affiliation(s)
- Ananya Chakraborty
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Amanda Paynter
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Mark Szendrey
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - James D Cornwell
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Wentao Li
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Jun Guo
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Tonghua Yang
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Yuan Du
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Tingzhong Wang
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Shetuan Zhang
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada.
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Celotto C, Sánchez C, Abdollahpur M, Sandberg F, Rodriguez Mstas JF, Laguna P, Pueyo E. The frequency of atrial fibrillatory waves is modulated by the spatiotemporal pattern of acetylcholine release: a 3D computational study. Front Physiol 2024; 14:1189464. [PMID: 38235381 PMCID: PMC10791938 DOI: 10.3389/fphys.2023.1189464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Accepted: 10/10/2023] [Indexed: 01/19/2024] Open
Abstract
In atrial fibrillation (AF), the ECG P-wave, which represents atrial depolarization, is replaced with chaotic and irregular fibrillation waves (f waves). The f-wave frequency, F f, shows significant variations over time. Cardiorespiratory interactions regulated by the autonomic nervous system have been suggested to play a role in such variations. We conducted a simulation study to test whether the spatiotemporal release pattern of the parasympathetic neurotransmitter acetylcholine (ACh) modulates the frequency of atrial reentrant circuits. Understanding parasympathetic involvement in AF may guide more effective treatment approaches and could help to design autonomic markers alternative to heart rate variability (HRV), which is not available in AF patients. 2D tissue and 3D whole-atria models of human atrial electrophysiology in persistent AF were built. Different ACh release percentages (8% and 30%) and spatial ACh release patterns, including spatially random release and release from ganglionated plexi (GPs) and associated nerves, were considered. The temporal pattern of ACh release, ACh(t), was simulated following a sinusoidal waveform of frequency 0.125 Hz to represent the respiratory frequency. Different mean concentrations ( A C h ¯ ) and peak-to-peak ranges of ACh (ΔACh) were tested. We found that temporal variations in F f, F f(t), followed the simulated temporal ACh(t) pattern in all cases. The temporal mean of F f(t), F ¯ f , depended on the fibrillatory pattern (number and location of rotors), the percentage of ACh release nodes and A C h ¯ . The magnitude of F f(t) modulation, ΔF f, depended on the percentage of ACh release nodes and ΔACh. The spatial pattern of ACh release did not have an impact on F ¯ f and only a mild impact on ΔF f. The f-wave frequency, being indicative of vagal activity, has the potential to drive autonomic-based therapeutic actions and could replace HRV markers not quantifiable from AF patients.
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Affiliation(s)
- Chiara Celotto
- BSICoS Group, I3A and IIS-Aragón, University of Zaragoza, Zaragoza, Spain
- CIBER - Bioingeniería, Biomateriales, y Nanomedicina (CIBER-BBN), Zaragoza, Spain
| | - Carlos Sánchez
- BSICoS Group, I3A and IIS-Aragón, University of Zaragoza, Zaragoza, Spain
- CIBER - Bioingeniería, Biomateriales, y Nanomedicina (CIBER-BBN), Zaragoza, Spain
| | | | - Frida Sandberg
- Department of Biomedical Engineering, Lund University, Lund, Sweden
| | | | - Pablo Laguna
- BSICoS Group, I3A and IIS-Aragón, University of Zaragoza, Zaragoza, Spain
- CIBER - Bioingeniería, Biomateriales, y Nanomedicina (CIBER-BBN), Zaragoza, Spain
| | - Esther Pueyo
- BSICoS Group, I3A and IIS-Aragón, University of Zaragoza, Zaragoza, Spain
- CIBER - Bioingeniería, Biomateriales, y Nanomedicina (CIBER-BBN), Zaragoza, Spain
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Benzoni P, Da Dalt L, Elia N, Popolizio V, Cospito A, Giannetti F, Dell’Era P, Olesen MS, Bucchi A, Baruscotti M, Norata GD, Barbuti A. PITX2 gain-of-function mutation associated with atrial fibrillation alters mitochondrial activity in human iPSC atrial-like cardiomyocytes. Front Physiol 2023; 14:1250951. [PMID: 38028792 PMCID: PMC10679737 DOI: 10.3389/fphys.2023.1250951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 10/20/2023] [Indexed: 12/01/2023] Open
Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia worldwide; however, the underlying causes of AF initiation are still poorly understood, particularly because currently available models do not allow in distinguishing the initial causes from maladaptive remodeling that induces and perpetuates AF. Lately, the genetic background has been proven to be important in the AF onset. iPSC-derived cardiomyocytes, being patient- and mutation-specific, may help solve this diatribe by showing the initial cell-autonomous changes underlying the development of the disease. Transcription factor paired-like homeodomain 2 (PITX2) has been identified as a key regulator of atrial development/differentiation, and the PITX2 genomic locus has the highest association with paroxysmal AF. PITX2 influences mitochondrial activity, and alterations in either its expression or function have been widely associated with AF. In this work, we investigate the activity of mitochondria in iPSC-derived atrial cardiomyocytes (aCMs) obtained from a young patient (24 years old) with paroxysmal AF, carrying a gain-of-function mutation in PITX2 (rs138163892) and from its isogenic control (CTRL) in which the heterozygous point mutation has been reverted to WT. PITX2 aCMs show a higher mitochondrial content, increased mitochondrial activity, and superoxide production under basal conditions when compared to CTRL aCMs. However, increasing mitochondrial workload by FCCP or β-adrenergic stimulation allows us to unmask mitochondrial defects in PITX2 aCMs, which are incapable of responding efficiently to the higher energy demand, determining ATP deficiency.
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Affiliation(s)
- Patrizia Benzoni
- The Cell Physiology MiLab, Department Biosciences, Università degli Studi di Milano, Milano, Italy
| | - Lorenzo Da Dalt
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Milano, Italy
| | - Noemi Elia
- The Cell Physiology MiLab, Department Biosciences, Università degli Studi di Milano, Milano, Italy
- Cell Factory, Fondazione IRCCS Ca’Granda Ospedale Maggiore Policlinico, Milano, Italy
| | - Vera Popolizio
- The Cell Physiology MiLab, Department Biosciences, Università degli Studi di Milano, Milano, Italy
| | - Alessandro Cospito
- The Cell Physiology MiLab, Department Biosciences, Università degli Studi di Milano, Milano, Italy
| | - Federica Giannetti
- The Cell Physiology MiLab, Department Biosciences, Università degli Studi di Milano, Milano, Italy
- Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Istituto Auxologico Italiano IRCCS, Milano, Italy
| | - Patrizia Dell’Era
- Department of Molecular and Translational Medicine, Università degli Studi di Brescia, Brescia, Italy
| | - Morten S. Olesen
- The Heart Centre, Rigshospitalet, Laboratory for Molecular Cardiology, Department of Cardiology, University Hospital of Copenhagen, Copenhagen, Denmark
| | - Annalisa Bucchi
- The Cell Physiology MiLab, Department Biosciences, Università degli Studi di Milano, Milano, Italy
| | - Mirko Baruscotti
- The Cell Physiology MiLab, Department Biosciences, Università degli Studi di Milano, Milano, Italy
| | - Giuseppe Danilo Norata
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Milano, Italy
| | - Andrea Barbuti
- The Cell Physiology MiLab, Department Biosciences, Università degli Studi di Milano, Milano, Italy
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7
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Hwang S, Yoon B, Jo SH. Inhibitory effects of N-methyl-D-aspartate (NMDA) and α 1-adrenergic receptor antagonist ifenprodil on human Kv1.5 channel. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2023; 396:3149-3161. [PMID: 37166464 DOI: 10.1007/s00210-023-02521-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 05/04/2023] [Indexed: 05/12/2023]
Abstract
Ifenprodil has been known to reduce cardiac contractility and cerebral vasodilation by antagonizing α1-adrenergic and N-methyl D-aspartate receptor-mediated intracellular signals. This study aimed to investigate the direct effect of ifenprodil on the human voltage-gated Kv1.5 channel (hKv1.5) by using a Xenopus oocyte expression system and a two-microelectrode voltage clamp technique. The amplitudes of hKv1.5 currents, including peak and steady state, were suppressed in a concentration-dependent manner (IC50; 43.1 and 35.5 μM, respectively) after 6 min of ifenprodil treatment. However, these effects were ~ 80% reversed by washout, suggesting that ifenprodil directly inhibited the hKv1.5 independent of membrane receptors or intracellular signals. The inhibition rate of steady state showed voltage dependence, wherein the rates increased according to test voltage depolarization. Ifenprodil reduced the time constants of hKv1.5 inactivation but has higher effects on activation. hKv1.5 inhibition by ifenprodil showed use dependency because the drug more rapidly reduced the current at the higher activation frequencies, and subsequent reduction in frequency after high activation frequency caused a partial channel block relief. Therefore, ifenprodil directly blocked the hKv1.5 in an open state and accelerated the time course of the channel inactivation, which provided a biophysical mechanism for the hKv1.5 blocking effects of ifenprodil.
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Affiliation(s)
- Soobeen Hwang
- Department of Physiology, Institute of Bioscience and Biotechnology, BK21 plus Graduate Program, Kangwon National University College of Medicine, Hyoja-Dong, Chuncheon, 200-701, Korea
| | - Byeongjun Yoon
- Department of Physiology, Institute of Bioscience and Biotechnology, BK21 plus Graduate Program, Kangwon National University College of Medicine, Hyoja-Dong, Chuncheon, 200-701, Korea
| | - Su-Hyun Jo
- Department of Physiology, Institute of Bioscience and Biotechnology, BK21 plus Graduate Program, Kangwon National University College of Medicine, Hyoja-Dong, Chuncheon, 200-701, Korea.
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8
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Giommi A, Gurgel ARB, Smith GL, Workman AJ. Does the small conductance Ca 2+-activated K + current I SK flow under physiological conditions in rabbit and human atrial isolated cardiomyocytes? J Mol Cell Cardiol 2023; 183:70-80. [PMID: 37704101 DOI: 10.1016/j.yjmcc.2023.09.002] [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: 06/26/2023] [Revised: 08/16/2023] [Accepted: 09/02/2023] [Indexed: 09/15/2023]
Abstract
BACKGROUND The small conductance Ca2+-activated K+ current (ISK) is a potential therapeutic target for treating atrial fibrillation. AIM To clarify, in rabbit and human atrial cardiomyocytes, the intracellular [Ca2+]-sensitivity of ISK, and its contribution to action potential (AP) repolarisation, under physiological conditions. METHODS Whole-cell-patch clamp, fluorescence microscopy: to record ion currents, APs and [Ca2+]i; 35-37°C. RESULTS In rabbit atrial myocytes, 0.5 mM Ba2+ (positive control) significantly decreased whole-cell current, from -12.8 to -4.9 pA/pF (P < 0.05, n = 17 cells, 8 rabbits). By contrast, the ISK blocker apamin (100 nM) had no effect on whole-cell current, at any set [Ca2+]i (∼100-450 nM). The ISK blocker ICAGEN (1 μM: ≥2 x IC50) also had no effect on current over this [Ca2+]i range. In human atrial myocytes, neither 1 μM ICAGEN (at [Ca2+]i ∼ 100-450 nM), nor 100 nM apamin ([Ca2+]i ∼ 250 nM) affected whole-cell current (5-10 cells, 3-5 patients/group). APs were significantly prolonged (at APD30 and APD70) by 2 mM 4-aminopyridine (positive control) in rabbit atrial myocytes, but 1 μM ICAGEN had no effect on APDs, versus either pre-ICAGEN or time-matched controls. High concentration (10 μM) ICAGEN (potentially ISK-non-selective) moderately increased APD70 and APD90, by 5 and 26 ms, respectively. In human atrial myocytes, 1 μM ICAGEN had no effect on APD30-90, whether stimulated at 1, 2 or 3 Hz (6-9 cells, 2-4 patients/rate). CONCLUSION ISK does not flow in human or rabbit atrial cardiomyocytes with [Ca2+]i set within the global average diastolic-systolic range, nor during APs stimulated at physiological or supra-physiological (≤3 Hz) rates.
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Affiliation(s)
- Alessandro Giommi
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK
| | - Aline R B Gurgel
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK
| | - Godfrey L Smith
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK
| | - Antony J Workman
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK.
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9
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Zhang X, Ni H, Morotti S, Smith C, Sato D, Louch W, Edwards A, Grandi E. Mechanisms of spontaneous Ca 2+ release-mediated arrhythmia in a novel 3D human atrial myocyte model: I. Transverse-axial tubule variation. J Physiol 2023; 601:2655-2683. [PMID: 36094888 PMCID: PMC10008525 DOI: 10.1113/jp283363] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 09/02/2022] [Indexed: 11/08/2022] Open
Abstract
Intracellular calcium (Ca2+ ) cycling is tightly regulated in the healthy heart ensuring effective contraction. This is achieved by transverse (t)-tubule membrane invaginations that facilitate close coupling of key Ca2+ -handling proteins such as the L-type Ca2+ channel and Na+ -Ca2+ exchanger (NCX) on the cell surface with ryanodine receptors (RyRs) on the intracellular Ca2+ store. Although less abundant and regular than in the ventricle, t-tubules also exist in atrial myocytes as a network of transverse invaginations with axial extensions known as the transverse-axial tubule system (TATS). In heart failure and atrial fibrillation, there is TATS remodelling that is associated with aberrant Ca2+ -handling and Ca2+ -induced arrhythmic activity; however, the mechanism underlying this is not fully understood. To address this, we developed a novel 3D human atrial myocyte model that couples electrophysiology and Ca2+ -handling with variable TATS organization and density. We extensively parameterized and validated our model against experimental data to build a robust tool examining TATS regulation of subcellular Ca2+ release. We found that varying TATS density and thus the localization of key Ca2+ -handling proteins has profound effects on Ca2+ handling. Following TATS loss, there is reduced NCX that results in increased cleft Ca2+ concentration through decreased Ca2+ extrusion. This elevated Ca2+ increases RyR open probability causing spontaneous Ca2+ releases and the promotion of arrhythmogenic waves (especially in the cell interior) leading to voltage instabilities through delayed afterdepolarizations. In summary, the present study demonstrates a mechanistic link between TATS remodelling and Ca2+ -driven proarrhythmic behaviour that probably reflects the arrhythmogenic state observed in disease. KEY POINTS: Transverse-axial tubule systems (TATS) modulate Ca2+ handling and excitation-contraction coupling in atrial myocytes, with TATS remodelling in heart failure and atrial fibrillation being associated with altered Ca2+ cycling and subsequent arrhythmogenesis. To investigate the poorly understood mechanisms linking TATS variation and spontaneous Ca2+ release, we built, parameterized and validated a 3D human atrial myocyte model coupling electrophysiology and spatially-detailed subcellular Ca2+ handling governed by the TATS. Simulated TATS loss causes diastolic Ca2+ and voltage instabilities through reduced Na+ -Ca2+ exchanger-mediated Ca2+ removal, cleft Ca2+ accumulation and increased ryanodine receptor open probability, resulting in spontaneous Ca2+ release and promotion of arrhythmogenic waves and delayed afterdepolarizations. At fast electrical rates typical of atrial tachycardia/fibrillation, spontaneous Ca2+ releases are larger and more frequent in the cell interior than at the periphery. Our work provides mechanistic insight into how atrial TATS remodelling can lead to Ca2+ -driven instabilities that may ultimately contribute to the arrhythmogenic state in disease.
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Affiliation(s)
- X. Zhang
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - H. Ni
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - S. Morotti
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - C.E.R. Smith
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - D. Sato
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - W.E. Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo Norway
| | - A.G. Edwards
- Department of Pharmacology, University of California Davis, Davis, CA, USA
- Simula Research Laboratory, Lysaker, Norway
| | - E. Grandi
- Department of Pharmacology, University of California Davis, Davis, CA, USA
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10
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Darkow E, Yusuf D, Rajamani S, Backofen R, Kohl P, Ravens U, Peyronnet R. Meta-Analysis of Mechano-Sensitive Ion Channels in Human Hearts: Chamber- and Disease-Preferential mRNA Expression. Int J Mol Sci 2023; 24:10961. [PMID: 37446137 DOI: 10.3390/ijms241310961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 06/19/2023] [Accepted: 06/27/2023] [Indexed: 07/15/2023] Open
Abstract
The cardiac cell mechanical environment changes on a beat-by-beat basis as well as in the course of various cardiac diseases. Cells sense and respond to mechanical cues via specialized mechano-sensors initiating adaptive signaling cascades. With the aim of revealing new candidates underlying mechano-transduction relevant to cardiac diseases, we investigated mechano-sensitive ion channels (MSC) in human hearts for their chamber- and disease-preferential mRNA expression. Based on a meta-analysis of RNA sequencing studies, we compared the mRNA expression levels of MSC in human atrial and ventricular tissue samples from transplant donor hearts (no cardiac disease), and from patients in sinus rhythm (underlying diseases: heart failure, coronary artery disease, heart valve disease) or with atrial fibrillation. Our results suggest that a number of MSC genes are expressed chamber preferentially, e.g., CHRNE in the atria (compared to the ventricles), TRPV4 in the right atrium (compared to the left atrium), CACNA1B and KCNMB1 in the left atrium (compared to the right atrium), as well as KCNK2 and KCNJ2 in ventricles (compared to the atria). Furthermore, 15 MSC genes are differentially expressed in cardiac disease, out of which SCN9A (lower expressed in heart failure compared to donor tissue) and KCNQ5 (lower expressed in atrial fibrillation compared to sinus rhythm) show a more than twofold difference, indicative of possible functional relevance. Thus, we provide an overview of cardiac MSC mRNA expression in the four cardiac chambers from patients with different cardiac diseases. We suggest that the observed differences in MSC mRNA expression may identify candidates involved in altered mechano-transduction in the respective diseases.
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Affiliation(s)
- Elisa Darkow
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg∙Bad Krozingen, 79110 Freiburg im Breisgau, Germany
- Medical Center and Faculty of Medicine, University of Freiburg, 79110 Freiburg im Breisgau, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, 79104 Freiburg im Breisgau, Germany
- Faculty of Biology, University of Freiburg, 79104 Freiburg im Breisgau, Germany
| | - Dilmurat Yusuf
- Bioinformatics Group, Department of Computer Science, University of Freiburg, 79110 Freiburg im Breisgau, Germany
| | - Sridharan Rajamani
- Translational Safety and Bioanalytical Sciences, Amgen Research, Amgen Inc., South San Francisco, CA 91320, USA
| | - Rolf Backofen
- Bioinformatics Group, Department of Computer Science, University of Freiburg, 79110 Freiburg im Breisgau, Germany
- Centre for Integrative Biological Signalling Studies (CIBSS), University of Freiburg, 79104 Freiburg im Breisgau, Germany
| | - Peter Kohl
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg∙Bad Krozingen, 79110 Freiburg im Breisgau, Germany
- Medical Center and Faculty of Medicine, University of Freiburg, 79110 Freiburg im Breisgau, Germany
- Centre for Integrative Biological Signalling Studies (CIBSS), University of Freiburg, 79104 Freiburg im Breisgau, Germany
| | - Ursula Ravens
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg∙Bad Krozingen, 79110 Freiburg im Breisgau, Germany
- Medical Center and Faculty of Medicine, University of Freiburg, 79110 Freiburg im Breisgau, Germany
| | - Rémi Peyronnet
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg∙Bad Krozingen, 79110 Freiburg im Breisgau, Germany
- Medical Center and Faculty of Medicine, University of Freiburg, 79110 Freiburg im Breisgau, Germany
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11
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Shi X, Tang X, Yao F, Wang L, Zhang M, Wang X, Yue G, Wang L, Hu S, Zhou B. Isolation of porcine adult cardiomyocytes: Comparison between Langendorff perfusion and tissue slicing-assisted enzyme digestion. PLoS One 2023; 18:e0285169. [PMID: 37235559 DOI: 10.1371/journal.pone.0285169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Accepted: 04/17/2023] [Indexed: 05/28/2023] Open
Abstract
Tissue slicing-assisted digestion (TSAD) of adult cardiomyocytes has shown significant improvements over conventional chunk methods. However, it remains unclear how this method compares to Langendorff perfusion, the current standard of adult cardiomyocyte isolation. Using adult Bama minipigs, we performed cardiomyocyte isolation via these two distinct methods, and compared the resulting cellular quality, including viability, cellular structure, gene expression, and electrophysiological properties, of cardiomyocytes from 3 distinct anatomical regions, namely the left ventricle, right ventricle, and left atrial appendage. Our results revealed largely indistinguishable cell quality in all of the measured parameters. These findings suggest that that TSAD can be reliably used to isolate adult mammalian cardiomyocytes as a reliable alternative to perfusion in cardiomyocyte isolation from larger mammals, particularly when Langendorff perfusion is not feasible.
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Affiliation(s)
- Xun Shi
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xiaoli Tang
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Fang Yao
- Shenzhen Key Laboratory of Cardiovascular Disease, Fuwai Hospital Chinese Academy of Medical Science, Shenzhen, Shenzhen, China
| | - Le Wang
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Mingzhi Zhang
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xin Wang
- Division of Prevention and Community Health, National Center for Cardiovascular Disease, National Clinical Research Center of Cardiovascular Disease, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
- State Key Laboratory of Cardiovascular Disease, Center for Cardiovascular Experimental Study and Evaluation, National Center for Cardiovascular Diseases, Beijing Key Laboratory of Pre-clinical Research and Evaluation for Cardiovascular Implant Materials, Animal Experimental Center, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College
| | - Guangxin Yue
- State Key Laboratory of Cardiovascular Disease, Center for Cardiovascular Experimental Study and Evaluation, National Center for Cardiovascular Diseases, Beijing Key Laboratory of Pre-clinical Research and Evaluation for Cardiovascular Implant Materials, Animal Experimental Center, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College
| | - Li Wang
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Shenzhen Key Laboratory of Cardiovascular Disease, Fuwai Hospital Chinese Academy of Medical Science, Shenzhen, Shenzhen, China
| | - Shengshou Hu
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Shenzhen Key Laboratory of Cardiovascular Disease, Fuwai Hospital Chinese Academy of Medical Science, Shenzhen, Shenzhen, China
| | - Bingying Zhou
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Shenzhen Key Laboratory of Cardiovascular Disease, Fuwai Hospital Chinese Academy of Medical Science, Shenzhen, Shenzhen, China
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12
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Richter-Laskowska M, Trybek P, Delfino DV, Wawrzkiewicz-Jałowiecka A. Flavonoids as Modulators of Potassium Channels. Int J Mol Sci 2023; 24:1311. [PMID: 36674825 PMCID: PMC9861088 DOI: 10.3390/ijms24021311] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 01/02/2023] [Accepted: 01/04/2023] [Indexed: 01/12/2023] Open
Abstract
Potassium channels are widely distributed integral proteins responsible for the effective and selective transport of K+ ions through the biological membranes. According to the existing structural and mechanistic differences, they are divided into several groups. All of them are considered important molecular drug targets due to their physiological roles, including the regulation of membrane potential or cell signaling. One of the recent trends in molecular pharmacology is the evaluation of the therapeutic potential of natural compounds and their derivatives, which can exhibit high specificity and effectiveness. Among the pharmaceuticals of plant origin, which are potassium channel modulators, flavonoids appear as a powerful group of biologically active substances. It is caused by their well-documented anti-oxidative, anti-inflammatory, anti-mutagenic, anti-carcinogenic, and antidiabetic effects on human health. Here, we focus on presenting the current state of knowledge about the possibilities of modulation of particular types of potassium channels by different flavonoids. Additionally, the biological meaning of the flavonoid-mediated changes in the activity of K+ channels will be outlined. Finally, novel promising directions for further research in this area will be proposed.
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Affiliation(s)
- Monika Richter-Laskowska
- The Centre for Biomedical Engineering, Łukasiewicz Research Network—Krakow Institute of Technology, 30-418 Krakow, Poland
| | - Paulina Trybek
- Faculty of Science and Technology, University of Silesia in Katowice, 41-500 Chorzów, Poland
| | | | - Agata Wawrzkiewicz-Jałowiecka
- Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, 44-100 Gliwice, Poland
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13
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Sano T, Inoue T, Irie N, Ichikawa T, Iai A, Osa K, Ono S, Asanuma K, Kaneko S, Kuribara T, Shigeyoshi I, Matsubara K, Suzuki K, Ishizu H, Sunagawa K. An incidentally discovered paraganglioma that caused sinus arrest after resection. THE JOURNAL OF MEDICAL INVESTIGATION 2023; 70:503-507. [PMID: 37940539 DOI: 10.2152/jmi.70.503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2023]
Abstract
Paragangliomas are neural-crest-derived nonepithelial neuroendocrine tumors distributed along the parasympathetic and sympathetic nerves. To our knowledge, no studies were reported regarding sinus arrest on day 4 after paraganglioma resection. A 66-year-old female patient with a history of pulmonary vein isolation visited our department for sigmoid colon cancer treatment. Enhanced computed tomography revealed an enhanced small nodule-like lymph node near the root of the inferior mesenteric artery. The patient underwent laparoscopic colectomy with regional lymph node dissection. Postoperatively, paroxysmal atrial fibrillation attacks developed, and the patient resumed oral medication. Additionally, sinus arrest after tachycardia developed. Changing the oral medication could maintain her circulatory dynamics. Pathological examination revealed that differentiated tubular adenocarcinoma infiltrated the submucosa. Immunohistochemically, the excised nodule as a lymph node was considered a functional paraganglioma. Our case indicates that paraganglioma resection and oral medication resumption may contribute to sinus arrest. When arrhythmias affecting the circulation occur perioperatively, the presence of a catecholamine-producing tumor should be considered in addition to cardiac disease. J. Med. Invest. 70 : 503-507, August, 2023.
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Affiliation(s)
- Takayuki Sano
- Department of Surgery, Saitama Cooperative Hospital, Saitama, Japan
| | - Takeshi Inoue
- Department of Surgery, Saitama Cooperative Hospital, Saitama, Japan
| | - Naoko Irie
- Department of Surgery, Saitama Cooperative Hospital, Saitama, Japan
| | - Tatsuo Ichikawa
- Department of Surgery, Saitama Cooperative Hospital, Saitama, Japan
| | - Akira Iai
- Department of Surgery, Saitama Cooperative Hospital, Saitama, Japan
| | - Kiyoshi Osa
- Department of Surgery, Saitama Cooperative Hospital, Saitama, Japan
| | - Satoshi Ono
- Department of Surgery, Saitama Cooperative Hospital, Saitama, Japan
| | - Kozo Asanuma
- Department of Surgery, Saitama Cooperative Hospital, Saitama, Japan
| | - Shiori Kaneko
- Department of Surgery, Saitama Cooperative Hospital, Saitama, Japan
| | - Tadao Kuribara
- Department of Surgery, Saitama Cooperative Hospital, Saitama, Japan
| | - Itaru Shigeyoshi
- Department of Surgery, Saitama Cooperative Hospital, Saitama, Japan
| | - Kouta Matsubara
- Department of Surgery, Saitama Cooperative Hospital, Saitama, Japan
| | - Kanako Suzuki
- Department of Surgery, Saitama Cooperative Hospital, Saitama, Japan
| | - Hideki Ishizu
- Department of Pathology, Saitama Cooperative Hospital, Saitama, Japan
| | - Keishin Sunagawa
- Department of Pathology, Saitama Cooperative Hospital, Saitama, Japan
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14
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Zhou B, Shi X, Tang X, Zhao Q, Wang L, Yao F, Hou Y, Wang X, Feng W, Wang L, Sun X, Wang L, Hu S. Functional isolation, culture and cryopreservation of adult human primary cardiomyocytes. Signal Transduct Target Ther 2022; 7:254. [PMID: 35882831 PMCID: PMC9325714 DOI: 10.1038/s41392-022-01044-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 04/11/2022] [Accepted: 05/26/2022] [Indexed: 12/27/2022] Open
Abstract
Cardiovascular diseases are the most common cause of death globally. Accurately modeling cardiac homeostasis, dysfunction, and drug response lies at the heart of cardiac research. Adult human primary cardiomyocytes (hPCMs) are a promising cellular model, but unstable isolation efficiency and quality, rapid cell death in culture, and unknown response to cryopreservation prevent them from becoming a reliable and flexible in vitro cardiac model. Combing the use of a reversible inhibitor of myosin II ATPase, (-)-blebbistatin (Bleb), and multiple optimization steps of the isolation procedure, we achieved a 2.74-fold increase in cell viability over traditional methods, accompanied by better cellular morphology, minimally perturbed gene expression, intact electrophysiology, and normal neurohormonal signaling. Further optimization of culture conditions established a method that was capable of maintaining optimal cell viability, morphology, and mitochondrial respiration for at least 7 days. Most importantly, we successfully cryopreserved hPCMs, which were structurally, molecularly, and functionally intact after undergoing the freeze-thaw cycle. hPCMs demonstrated greater sensitivity towards a set of cardiotoxic drugs, compared to human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Further dissection of cardiomyocyte drug response at both the population and single-cell transcriptomic level revealed that hPCM responses were more pronouncedly enriched in cardiac function, whereas hiPSC-CMs responses reflected cardiac development. Together, we established a full set of methodologies for the efficient isolation and prolonged maintenance of functional primary adult human cardiomyocytes in vitro, unlocking their potential as a cellular model for cardiovascular research, drug discovery, and safety pharmacology.
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Affiliation(s)
- Bingying Zhou
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Shenzhen Key Laboratory of Cardiovascular Disease, Fuwai Hospital Chinese Academy of Medical Sciences, Shenzhen, Shenzhen, China
| | - Xun Shi
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xiaoli Tang
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Quanyi Zhao
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Shenzhen Key Laboratory of Cardiovascular Disease, Fuwai Hospital Chinese Academy of Medical Sciences, Shenzhen, Shenzhen, China
| | - Le Wang
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Fang Yao
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yongfeng Hou
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,18 Jinma Industrial Park, Fangshan District, Beijing, China
| | - Xianqiang Wang
- Department of Cardiac Surgery, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Wei Feng
- Department of Cardiac Surgery, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Liqing Wang
- Department of Cardiac Surgery, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xiaogang Sun
- Department of Cardiac Surgery, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Li Wang
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Shenzhen Key Laboratory of Cardiovascular Disease, Fuwai Hospital Chinese Academy of Medical Sciences, Shenzhen, Shenzhen, China
| | - Shengshou Hu
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China. .,Shenzhen Key Laboratory of Cardiovascular Disease, Fuwai Hospital Chinese Academy of Medical Sciences, Shenzhen, Shenzhen, China. .,Department of Cardiac Surgery, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
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15
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Iwasaki YK, Sekiguchi A, Kato T, Yamashita T. Glucocorticoid Induces Atrial Arrhythmogenesis via Modification of Ion Channel Gene Expression in Rats. Int Heart J 2022; 63:375-383. [PMID: 35354756 DOI: 10.1536/ihj.21-677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Excess psychological stress is one of the precipitating factors for paroxysmal atrial fibrillation (AF), although the involved mechanisms are still uncertain. To test a hypothesis that one of the stress-induced hormones, glucocorticoid, is involved in the pathogenesis of stress-induced AF, we investigated whether the glucocorticoid could alter the temporal profile of cardiac ion channels gene expression, thereby leading to atrial arrhythmogenesis.Dexamethasone (DEX, 1.0 mg/kg) was injected subcutaneously in Sprague-Dawley rats. At predetermined times after DEX injection (0, 1, 3, 6, 12, and 24 hours), the mRNA levels of cardiac ion channel genes (erg, KvLQT1, Kv4.3, Kv4.2, Kv2.1, Kv1.5, Kv1.4, Kv1.2, SUR2A, Kir6.2, Kir3.4, Kir3.1 Kir2.2, Kir2.1, SCN5A, and α1C) were determined using RNase protection assay. DEX induced immediate and transient increase in the mRNA level of Kv1.5 and Kir2.2 with peaks at 6 (5.0 fold) and 3 hours (3.3 fold) after DEX injection, respectively. Patch-clamp studies revealed a significantly increased current density of the corresponding current, IKur and IK1 at 6 hours after DEX injection. Simultaneously, electrophysiological study in isolated perfused hearts showed significantly increased number of repetitive atrial responses induced by single atrial extrastimulus (3.2 ± 2.4 to 26.7 ± 16.4, P = 0.004) with shorting of the refractory period (36.4 ± 4.6 to 27.4 ± 5.5 ms, P = 0.049) after DEX injection.Glucocorticoid immediately modified Kv1.5 and Kir2.2 gene expression at pretranslational levels, thus leading to effective refractory period shortening that could be arrhythmogenic. These results implied that transient glucocorticoid-induced biochemical modification of cardiac ion channels might be one of the mechanisms underlying the stress-induced paroxysmal AF.
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Affiliation(s)
- Yu-Ki Iwasaki
- Department of Cardiovascular Medicine, Nippon Medical School
| | | | - Takeshi Kato
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kanazawa University
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16
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Lee HM, Hahn SJ, Choi BH. The antidiabetic drug rosiglitazone blocks Kv1.5 potassium channels in an open state. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY 2022; 26:135-144. [PMID: 35203063 PMCID: PMC8890944 DOI: 10.4196/kjpp.2022.26.2.135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 01/15/2022] [Accepted: 01/17/2022] [Indexed: 11/15/2022]
Abstract
An antidiabetic drug, rosiglitazone is a member of the drug class of thiazolidinedione. Although restrictions on use due to the possibility of heart toxicity have been removed, it is still a drug that is concerned about side effects on the heart. We here examined, using Chinese hamster ovary cells, the action of rosiglitazone on Kv1.5 channels, which is a major determinant of the duration of cardiac action potential. Rosiglitazone rapidly and reversibly inhibited Kv1.5 currents in a concentration-dependent manner (IC50 = 18.9 µM) and accelerated the decay of Kv1.5 currents without modifying the activation kinetics. In addition, the deactivation of Kv1.5 current, assayed with tail current, was slowed by the drug. All of the results as well as the use-dependence of the rosiglitazone-mediated blockade indicate that rosiglitazone acts on Kv1.5 channels as an open channel blocker. This study suggests that the cardiac side effects of rosiglitazone might be mediated in part by suppression of Kv1.5 channels, and therefore, raises a concern of using the drug for diabetic therapeutics.
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Affiliation(s)
- Hyang Mi Lee
- Department of Pharmacology, Institute for Medical Sciences, Jeonbuk National University Medical School, Jeonju 54097, Korea
| | - Sang June Hahn
- Department of Physiology, Medical Research Center, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Bok Hee Choi
- Department of Pharmacology, Institute for Medical Sciences, Jeonbuk National University Medical School, Jeonju 54097, Korea
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17
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Bae H, Kim T, Lim I. Carbon monoxide activation of delayed rectifier potassium currents of human cardiac fibroblasts through diverse pathways. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2022; 26:25-36. [PMID: 34965993 PMCID: PMC8723981 DOI: 10.4196/kjpp.2022.26.1.25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/28/2021] [Accepted: 09/28/2021] [Indexed: 06/14/2023]
Abstract
To identify the effect and mechanism of carbon monoxide (CO) on delayed rectifier K+ currents (IK) of human cardiac fibroblasts (HCFs), we used the wholecell mode patch-clamp technique. Application of CO delivered by carbon monoxidereleasing molecule-3 (CORM3) increased the amplitude of outward K+ currents, and diphenyl phosphine oxide-1 (a specific IK blocker) inhibited the currents. CORM3- induced augmentation was blocked by pretreatment with nitric oxide synthase blockers (L-NG-monomethyl arginine citrate and L-NG-nitro arginine methyl ester). Pretreatment with KT5823 (a protein kinas G blocker), 1H-[1,-2,-4] oxadiazolo-[4,-3-a] quinoxalin-1-on (ODQ, a soluble guanylate cyclase blocker), KT5720 (a protein kinase A blocker), and SQ22536 (an adenylate cyclase blocker) blocked the CORM3 stimulating effect on IK. In addition, pretreatment with SB239063 (a p38 mitogen-activated protein kinase [MAPK] blocker) and PD98059 (a p44/42 MAPK blocker) also blocked the CORM3's effect on the currents. When testing the involvement of S-nitrosylation, pretreatment of N-ethylmaleimide (a thiol-alkylating reagent) blocked CO-induced IK activation and DL-dithiothreitol (a reducing agent) reversed this effect. Pretreatment with 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)-21H,23H porphyrin manganese (III) pentachloride and manganese (III) tetrakis (4-benzoic acid) porphyrin chloride (superoxide dismutase mimetics), diphenyleneiodonium chloride (an NADPH oxidase blocker), or allopurinol (a xanthine oxidase blocker) also inhibited CO-induced IK activation. These results suggest that CO enhances IK in HCFs through the nitric oxide, phosphorylation by protein kinase G, protein kinase A, and MAPK, S-nitrosylation and reduction/oxidation (redox) signaling pathways.
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Affiliation(s)
- Hyemi Bae
- Department of Physiology, College of Medicine, Chung-Ang University, Seoul 06974, Korea
| | - Taeho Kim
- Department of Internal Medicine, College of Medicine, Chung-Ang University Hospital, Seoul 06973, Korea
| | - Inja Lim
- Department of Physiology, College of Medicine, Chung-Ang University, Seoul 06974, Korea
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18
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Kwon OS, Hwang I, Pak HN. Computational modeling of atrial fibrillation. INTERNATIONAL JOURNAL OF ARRHYTHMIA 2021. [DOI: 10.1186/s42444-021-00051-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
AbstractWith the aging society, the prevalence of atrial fibrillation (AF) continues to increase. Nevertheless, there are still limitations in antiarrhythmic drugs (AAD) or catheter interventions for AF. If it is possible to predict the outcome of AF management according to various AADs or ablation lesion sets through computational modeling, it will be of great clinical help. AF computational modeling has been utilized for in-silico arrhythmia research and enabled high-density entire chamber mapping, reproducible condition control, virtual intervention, not possible clinically or experimentally, in-depth mechanistic research. With the recent development of computer science and technology, more sophisticated and faster computational modeling has become available for clinical application. In particular, it can be applied to determine the extra-PV target of persistent AF catheter ablation or to select the AAD with the best effect. AF computational modeling combined with artificial intelligence is expected to contribute to precision medicine for more diverse uses in the future. Therefore, in this review, we will deal with the history, development, and various applications of computation modeling.
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19
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Jost N, Christ T, Magyar J. New Strategies for the Treatment of Atrial Fibrillation. Pharmaceuticals (Basel) 2021; 14:ph14090926. [PMID: 34577626 PMCID: PMC8466466 DOI: 10.3390/ph14090926] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 09/07/2021] [Accepted: 09/08/2021] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia in the clinical practice. It significantly contributes to the morbidity and mortality of the elderly population. Over the past 25-30 years intense effort in basic research has advanced the understanding of the relationship between the pathophysiology of AF and atrial remodelling. Nowadays it is clear that the various forms of atrial remodelling (electrical, contractile and structural) play crucial role in initiating and maintaining the persistent and permanent types of AF. Unlike in ventricular fibrillation, in AF rapid ectopic firing originating from pulmonary veins and re-entry mechanism may induce and maintain (due to atrial remodelling) this complex cardiac arrhythmia. The present review presents and discusses in detail the latest knowledge on the role of remodelling in AF. Special attention is paid to novel concepts and pharmacological targets presumably relevant to the drug treatment of atrial fibrillation.
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Affiliation(s)
- Norbert Jost
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, 6725 Szeged, Hungary
- Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, 6725 Szeged, Hungary
- ELKH-SZTE Research Group for Cardiovascular Pharmacology, Eötvös Loránd Research Network, 6725 Szeged, Hungary
- Correspondence:
| | - Torsten Christ
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany;
- DZHK (German Center for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - János Magyar
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary;
- Department of Sport Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
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20
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Quinazolinone dimers as a potential new class of safer Kv1 inhibitors: Overcoming hERG, sodium and calcium channel affinities. Bioorg Chem 2021; 115:105264. [PMID: 34416509 DOI: 10.1016/j.bioorg.2021.105264] [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: 03/21/2021] [Revised: 07/11/2021] [Accepted: 08/07/2021] [Indexed: 11/24/2022]
Abstract
The discovery of more selective and safer voltage-gated potassium channel blockers is an extremely demanding approach. Designing selective Kv1.5 inhibitors is very challenging as only limited data is available on this target due to a lacking crystal structure for this ion channel receptor. Herein, we synthesized a series of 21 novel quinazolinone dimers 3a-i, 5a-i and 10a-c. We tried to avoid structural features responsible for non-selectivity and for most potassium channel blockers' side effects in our design. In contrast to other works, which lack investigation over wide ranges of potassium and sodium channels, we screened the inhibitory activity of our synthesized compounds over multiple voltage-gated potassium channels, including six different human Kv1 channel subtypes Kv1.1, Kv1.2, Kv1.3, Kv1.4, Kv1.5 and Kv1.6 channels as well as Kv2.1, Kv3.1, Kv4.3, Kv7.2, Kv7.3, Kv10.1, hERG, and Shaker IR. Moreover, these compounds' selectivity was investigated on sodium channels Nav1.2, Nav1.4 and Nav1.5 and calcium channels Cav3.1-Cav3.3. The results revealed two compounds (3a and 3e) with low micromolar Kv1.5 inhibition activity with EC50 values of 5.1 ± 0.9 µM and 12.5 ± 1.1 µM, respectively. However, at higher concentrations, they also showed inhibitory activity on Kv1.3 and Kv1.1 channels. This might be due to structural similarities between these three Kv1 channel isoforms. Compound 3a shows a slight preference for Kv1.5. Interestingly, they lack any activity on other potassium channels (including hERG), sodium channels, and calcium channels. Our findings recommend quinazolinone dimers with ethylene linker as a potential new class of safer Kv1 inhibitors and a good start for designing more selective and potent Kv1.5 inhibitors.
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21
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Liu X, Duan X, Fan H, Wang H, Jiang X, Fang Y, Tang Q, Xiao J, Li Q. 8-hydroxypinoresinol-4-O-β-D-glucoside from Valeriana officinalis L. Is a Novel Kv1.5 Channel Blocker. JOURNAL OF ETHNOPHARMACOLOGY 2021; 276:114168. [PMID: 33932511 DOI: 10.1016/j.jep.2021.114168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 04/23/2021] [Accepted: 04/26/2021] [Indexed: 06/12/2023]
Abstract
ETHNOPHARMACOLOGY RELEVANCE In folkloric medicine of many cultures, one of the medical uses of Valeriana officinalis Linn is to treat heart-related disease. Recently, it was shown that the ethanol extracts from V. officinalis could effectively prevent auricular fibrillation, and 8-hydroxypinoresinol-4-O-β-D-glucoside (HPG) from the extracts is one of the two active compounds showing antiarrhythmia activities. AIM OF THE STUDY The human Kv1.5 channel (hKv1.5) has potential antiarrhythmia activities, and this study arms at investigating the current blocking effects of HPG on hKv1.5 channel. MATERIAL AND METHODS HPG was obtained from V. officinalis extracts, and hKv1.5 channels were expressed in HEK 293 cells. HPG was perfused while recording the current through hKv1.5 channels. Patch-clamp recording techniques were used to study the effects of HPG at various concentrations (10 μM, 30 μM, and 50 μM) on hKv1.5 channels. RESULTS The present study demonstrated that HPG inhibited hKv1.5 channel current in a concentration-dependent manner; the higher the concentration, the greater is the inhibition at each depolarization potential. During washout, the channels did not full recover indicating that the un-coupling between HPG and hKv1.5 channels is a slow process. CONCLUSION HPG may be an effective and safe active ingredient for AF having translational potential.
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Affiliation(s)
- Xingxing Liu
- Department of Integrated Traditional Chinese and Western Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Liberty Rd., Wuhan, Hubei, 430022, China
| | - Xueyun Duan
- Pharmaceutical Department, Hubei Provincial Hospital of Traditional Chinese Medicine, Wuhan, 430061, Hubei Province, China
| | - Heng Fan
- Department of Integrated Traditional Chinese and Western Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Liberty Rd., Wuhan, Hubei, 430022, China
| | - Hongfei Wang
- Department of Cardiac Surgery, Department of Integrated Traditional Chinese Medicine and Western Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Liberty Rd., Wuhan, Hubei, 430022, China
| | - Xionggang Jiang
- Department of Cardiac Surgery, Department of Integrated Traditional Chinese Medicine and Western Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Liberty Rd., Wuhan, Hubei, 430022, China
| | - Ying Fang
- Hubei University of Chinese Medicine, 16 Huangjiahu W Rd, Hongshan, Wuhan, Hubei, 430065, China
| | - Qing Tang
- Department of Integrated Traditional Chinese and Western Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Liberty Rd., Wuhan, Hubei, 430022, China
| | - Jun Xiao
- The Macrohard Institute of Health, 231 North Ave, Battle Creek, MI, 49017, USA.
| | - Qian Li
- The Macrohard Institute of Health, 231 North Ave, Battle Creek, MI, 49017, USA; The American Academy of Tradition Chinese Medicine Inc., 1925 W County Rd B2, Roseville, MN, 55113, USA.
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22
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Johnson M, Gomez-Galeno J, Ryan D, Okolotowicz K, McKeithan WL, Sampson KJ, Kass RS, Mercola M, Cashman JR. Human iPSC-derived cardiomyocytes and pyridyl-phenyl mexiletine analogs. Bioorg Med Chem Lett 2021; 46:128162. [PMID: 34062251 DOI: 10.1016/j.bmcl.2021.128162] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 04/16/2021] [Accepted: 05/26/2021] [Indexed: 11/15/2022]
Abstract
In the United States, approximately one million individuals are hospitalized every year for arrhythmias, making arrhythmias one of the top causes of healthcare expenditures. Mexiletine is currently used as an antiarrhythmic drug but has limitations. The purpose of this work was to use normal and Long QT syndrome Type 3 (LQTS3) patient-derived human induced pluripotent stem cell (iPSC)-derived cardiomyocytes to identify an analog of mexiletine with superior drug-like properties. Compared to racemic mexiletine, medicinal chemistry optimization of substituted racemic pyridyl phenyl mexiletine analogs resulted in a more potent sodium channel inhibitor with greater selectivity for the sodium over the potassium channel and for late over peak sodium current.
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Affiliation(s)
- Mark Johnson
- Human BioMolecular Research Institute, 6351 Nancy Ridge Dr. Suite B, San Diego, CA 92121, USA
| | - Jorge Gomez-Galeno
- Human BioMolecular Research Institute, 6351 Nancy Ridge Dr. Suite B, San Diego, CA 92121, USA
| | - Daniel Ryan
- Human BioMolecular Research Institute, 6351 Nancy Ridge Dr. Suite B, San Diego, CA 92121, USA
| | - Karl Okolotowicz
- Human BioMolecular Research Institute, 6351 Nancy Ridge Dr. Suite B, San Diego, CA 92121, USA
| | - Wesley L McKeithan
- Cardiovascular Institute and Department of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Kevin J Sampson
- Department of Pharmacology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Robert S Kass
- Department of Pharmacology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Mark Mercola
- Cardiovascular Institute and Department of Medicine, Stanford University, Stanford, CA 94305, USA
| | - John R Cashman
- Human BioMolecular Research Institute, 6351 Nancy Ridge Dr. Suite B, San Diego, CA 92121, USA.
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23
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Verkerk AO, Marchal GA, Zegers JG, Kawasaki M, Driessen AHG, Remme CA, de Groot JR, Wilders R. Patch-Clamp Recordings of Action Potentials From Human Atrial Myocytes: Optimization Through Dynamic Clamp. Front Pharmacol 2021; 12:649414. [PMID: 33912059 PMCID: PMC8072333 DOI: 10.3389/fphar.2021.649414] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 02/18/2021] [Indexed: 11/29/2022] Open
Abstract
Introduction: Atrial fibrillation (AF) is the most common cardiac arrhythmia. Consequently, novel therapies are being developed. Ultimately, the impact of compounds on the action potential (AP) needs to be tested in freshly isolated human atrial myocytes. However, the frequent depolarized state of these cells upon isolation seriously hampers reliable AP recordings. Purpose: We assessed whether AP recordings from single human atrial myocytes could be improved by providing these cells with a proper inward rectifier K+ current (IK1), and consequently with a regular, non-depolarized resting membrane potential (RMP), through “dynamic clamp”. Methods: Single myocytes were enzymatically isolated from left atrial appendage tissue obtained from patients with paroxysmal AF undergoing minimally invasive surgical ablation. APs were elicited at 1 Hz and measured using perforated patch-clamp methodology, injecting a synthetic IK1 to generate a regular RMP. The injected IK1 had strong or moderate rectification. For comparison, a regular RMP was forced through injection of a constant outward current. A wide variety of ion channel blockers was tested to assess their modulatory effects on AP characteristics. Results: Without any current injection, RMPs ranged from −9.6 to −86.2 mV in 58 cells. In depolarized cells (RMP positive to −60 mV), RMP could be set at −80 mV using IK1 or constant current injection and APs could be evoked upon stimulation. AP duration differed significantly between current injection methods (p < 0.05) and was shortest with constant current injection and longest with injection of IK1 with strong rectification. With moderate rectification, AP duration at 90% repolarization (APD90) was similar to myocytes with regular non-depolarized RMP, suggesting that a synthetic IK1 with moderate rectification is the most appropriate for human atrial myocytes. Importantly, APs evoked using each injection method were still sensitive to all drugs tested (lidocaine, nifedipine, E-4031, low dose 4-aminopyridine, barium, and apamin), suggesting that the major ionic currents of the atrial cells remained functional. However, certain drug effects were quantitatively dependent on the current injection approach used. Conclusion: Injection of a synthetic IK1 with moderate rectification facilitates detailed AP measurements in human atrial myocytes. Therefore, dynamic clamp represents a promising tool for testing novel antiarrhythmic drugs.
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Affiliation(s)
- Arie O Verkerk
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands.,Department of Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Gerard A Marchal
- Department of Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Jan G Zegers
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Makiri Kawasaki
- Department of Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Antoine H G Driessen
- Department of Cardiothoracic Surgery, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Carol Ann Remme
- Department of Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Joris R de Groot
- Department of Cardiology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Ronald Wilders
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
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24
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Nattel S, Sager PT, Hüser J, Heijman J, Dobrev D. Why translation from basic discoveries to clinical applications is so difficult for atrial fibrillation and possible approaches to improving it. Cardiovasc Res 2021; 117:1616-1631. [PMID: 33769493 DOI: 10.1093/cvr/cvab093] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 02/05/2021] [Indexed: 02/06/2023] Open
Abstract
Atrial fibrillation (AF) is the most common sustained clinical arrhythmia, with a lifetime incidence of up to 37%, and is a major contributor to population morbidity and mortality. Important components of AF management include control of cardiac rhythm, rate, and thromboembolic risk. In this narrative review article, we focus on rhythm-control therapy. The available therapies for cardiac rhythm control include antiarrhythmic drugs and catheter-based ablation procedures; both of these are presently neither optimally effective nor safe. In order to develop improved treatment options, it is necessary to use preclinical models, both to identify novel mechanism-based therapeutic targets and to test the effects of putative therapies before initiating clinical trials. Extensive research over the past 30 years has provided many insights into AF mechanisms that can be used to design new rhythm-maintenance approaches. However, it has proven very difficult to translate these mechanistic discoveries into clinically applicable safe and effective new therapies. The aim of this article is to explore the challenges that underlie this phenomenon. We begin by considering the basic problem of AF, including its clinical importance, the current therapeutic landscape, the drug development pipeline, and the notion of upstream therapy. We then discuss the currently available preclinical models of AF and their limitations, and move on to regulatory hurdles and considerations and then review industry concerns and strategies. Finally, we evaluate potential paths forward, attempting to derive insights from the developmental history of currently used approaches and suggesting possible paths for the future. While the introduction of successful conceptually innovative new treatments for AF control is proving extremely difficult, one significant breakthrough is likely to revolutionize both AF management and the therapeutic development landscape.
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Affiliation(s)
- Stanley Nattel
- Department of Medicine, Montreal Heart Institute and Université de Montréal, Montreal, Canada.,Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada.,IHU LIYRC Institute, Bordeaux, France.,Faculty of Medicine, Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany
| | - Philip T Sager
- Department of Medicine, Cardiovascuar Research Institute, Stanford University, Palo Alto, CA, USA
| | - Jörg Hüser
- Research and Development, Preclinical Research, Cardiovascular Diseases, Bayer AG, Wuppertal, Germany
| | - Jordi Heijman
- Faculty of Medicine, Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany.,Department of Cardiology, Cardiovascular Research Institute Maastricht, Faculty of Health, Medicine, and Life Sciences, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, The Netherlands
| | - Dobromir Dobrev
- Department of Medicine, Montreal Heart Institute and Université de Montréal, Montreal, Canada.,Faculty of Medicine, Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany.,Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, USA
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25
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Du Y, Wang T, Guo J, Li W, Yang T, Szendrey M, Zhang S. Kv1.5 channels are regulated by PKC-mediated endocytic degradation. J Biol Chem 2021; 296:100514. [PMID: 33676894 PMCID: PMC8050386 DOI: 10.1016/j.jbc.2021.100514] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 02/28/2021] [Accepted: 03/03/2021] [Indexed: 11/28/2022] Open
Abstract
The voltage-gated potassium channel Kv1.5 plays important roles in the repolarization of atrial action potentials and regulation of the vascular tone. While the modulation of Kv1.5 function has been well studied, less is known about how the protein levels of Kv1.5 on the cell membrane are regulated. Here, through electrophysiological and biochemical analyses of Kv1.5 channels heterologously expressed in HEK293 cells and neonatal rat ventricular myocytes, as well as native Kv1.5 in human induced pluripotent stem cell (iPSC)-derived atrial cardiomyocytes, we found that activation of protein kinase C (PKC) with phorbol 12-myristate 13-acetate (PMA, 10 nM) diminished Kv1.5 current (IKv1.5) and protein levels of Kv1.5 in the plasma membrane. Mechanistically, PKC activation led to monoubiquitination and degradation of the mature Kv1.5 proteins. Overexpression of Vps24, a protein that sorts transmembrane proteins into lysosomes via the multivesicular body (MVB) pathway, accelerated, whereas the lysosome inhibitor bafilomycin A1 completely prevented PKC-mediated Kv1.5 degradation. Kv1.5, but not Kv1.1, Kv1.2, Kv1.3, or Kv1.4, was uniquely sensitive to PMA treatment. Sequence alignments suggested that residues within the N terminus of Kv1.5 are essential for PKC-mediated Kv1.5 reduction. Using N-terminal truncation as well as site-directed mutagenesis, we identified that Thr15 is the target site for PKC that mediates endocytic degradation of Kv1.5 channels. These findings indicate that alteration of protein levels in the plasma membrane represents an important regulatory mechanism of Kv1.5 channel function under PKC activation conditions.
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Affiliation(s)
- Yuan Du
- Department of Cardiovascular Medicine, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China; Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Tingzhong Wang
- Department of Cardiovascular Medicine, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China; Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Jun Guo
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Wentao Li
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Tonghua Yang
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Mark Szendrey
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Shetuan Zhang
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada.
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26
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Kraft M, Büscher A, Wiedmann F, L’hoste Y, Haefeli WE, Frey N, Katus HA, Schmidt C. Current Drug Treatment Strategies for Atrial Fibrillation and TASK-1 Inhibition as an Emerging Novel Therapy Option. Front Pharmacol 2021; 12:638445. [PMID: 33897427 PMCID: PMC8058608 DOI: 10.3389/fphar.2021.638445] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Accepted: 01/21/2021] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) is the most common sustained arrhythmia with a prevalence of up to 4% and an upwards trend due to demographic changes. It is associated with an increase in mortality and stroke incidences. While stroke risk can be significantly reduced through anticoagulant therapy, adequate treatment of other AF related symptoms remains an unmet medical need in many cases. Two main treatment strategies are available: rate control that modulates ventricular heart rate and prevents tachymyopathy as well as rhythm control that aims to restore and sustain sinus rhythm. Rate control can be achieved through drugs or ablation of the atrioventricular node, rendering the patient pacemaker-dependent. For rhythm control electrical cardioversion and pharmacological cardioversion can be used. While electrical cardioversion requires fasting and sedation of the patient, antiarrhythmic drugs have other limitations. Most antiarrhythmic drugs carry a risk for pro-arrhythmic effects and are contraindicated in patients with structural heart diseases. Furthermore, catheter ablation of pulmonary veins can be performed with its risk of intraprocedural complications and varying success. In recent years TASK-1 has been introduced as a new target for AF therapy. Upregulation of TASK-1 in AF patients contributes to prolongation of the action potential duration. In a porcine model of AF, TASK-1 inhibition by gene therapy or pharmacological compounds induced cardioversion to sinus rhythm. The DOxapram Conversion TO Sinus rhythm (DOCTOS)-Trial will reveal whether doxapram, a potent TASK-1 inhibitor, can be used for acute cardioversion of persistent and paroxysmal AF in patients, potentially leading to a new treatment option for AF.
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Affiliation(s)
- Manuel Kraft
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
- HCR, Heidelberg Center for Heart Rhythm Disorders, University of Heidelberg, Heidelberg, Germany
| | - Antonius Büscher
- Clinic for Cardiology II: Electrophysiology, University Hospital Münster, Münster, Germany
| | - Felix Wiedmann
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
- HCR, Heidelberg Center for Heart Rhythm Disorders, University of Heidelberg, Heidelberg, Germany
| | - Yannick L’hoste
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
- HCR, Heidelberg Center for Heart Rhythm Disorders, University of Heidelberg, Heidelberg, Germany
| | - Walter E. Haefeli
- Department of Clinical Pharmacology and Pharmacoepidemiology, University of Heidelberg, Heidelberg, Germany
| | - Norbert Frey
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
- HCR, Heidelberg Center for Heart Rhythm Disorders, University of Heidelberg, Heidelberg, Germany
| | - Hugo A. Katus
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
- HCR, Heidelberg Center for Heart Rhythm Disorders, University of Heidelberg, Heidelberg, Germany
| | - Constanze Schmidt
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
- HCR, Heidelberg Center for Heart Rhythm Disorders, University of Heidelberg, Heidelberg, Germany
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27
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Verkerk AO, Wilders R. Dynamic Clamp in Electrophysiological Studies on Stem Cell-Derived Cardiomyocytes-Why and How? J Cardiovasc Pharmacol 2021; 77:267-279. [PMID: 33229908 DOI: 10.1097/fjc.0000000000000955] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 10/31/2020] [Indexed: 12/15/2022]
Abstract
ABSTRACT Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) are supposed to be a good human-based model, with virtually unlimited cell source, for studies on mechanisms underlying cardiac development and cardiac diseases, and for identification of drug targets. However, a major drawback of hPSC-CMs as a model system, especially for electrophysiological studies, is their depolarized state and associated spontaneous electrical activity. Various approaches are used to overcome this drawback, including the injection of "synthetic" inward rectifier potassium current (IK1), which is computed in real time, based on the recorded membrane potential ("dynamic clamp"). Such injection of an IK1-like current results in quiescent hPSC-CMs with a nondepolarized resting potential that show "adult-like" action potentials on stimulation, with functional availability of the most important ion channels involved in cardiac electrophysiology. These days, dynamic clamp has become a widely appreciated electrophysiological tool. However, setting up a dynamic clamp system can still be laborious and difficult, both because of the required hardware and the implementation of the dedicated software. In the present review, we first summarize the potential mechanisms underlying the depolarized state of hPSC-CMs and the functional consequences of this depolarized state. Next, we explain how an existing manual patch clamp setup can be extended with dynamic clamp. Finally, we shortly validate the extended setup with atrial-like and ventricular-like hPSC-CMs. We feel that dynamic clamp is a highly valuable tool in the field of cellular electrophysiological studies on hPSC-CMs and hope that our directions for setting up such dynamic clamp system may prove helpful.
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Affiliation(s)
- Arie O Verkerk
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands ; and
- Department of Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Ronald Wilders
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands ; and
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28
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Amuzescu B, Airini R, Epureanu FB, Mann SA, Knott T, Radu BM. Evolution of mathematical models of cardiomyocyte electrophysiology. Math Biosci 2021; 334:108567. [PMID: 33607174 DOI: 10.1016/j.mbs.2021.108567] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 01/10/2021] [Accepted: 02/04/2021] [Indexed: 12/16/2022]
Abstract
Advanced computational techniques and mathematical modeling have become more and more important to the study of cardiac electrophysiology. In this review, we provide a brief history of the evolution of cardiomyocyte electrophysiology models and highlight some of the most important ones that had a major impact on our understanding of the electrical activity of the myocardium and associated transmembrane ion fluxes in normal and pathological states. We also present the use of these models in the study of various arrhythmogenesis mechanisms, particularly the integration of experimental pharmacology data into advanced humanized models for in silico proarrhythmogenic risk prediction as an essential component of the Comprehensive in vitro Proarrhythmia Assay (CiPA) drug safety paradigm.
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Affiliation(s)
- Bogdan Amuzescu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, Bucharest 050095, Romania; Life, Environmental and Earth Sciences Division, Research Institute of the University of Bucharest (ICUB), 91-95 Splaiul Independentei, Bucharest 050095, Romania.
| | - Razvan Airini
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, Bucharest 050095, Romania; Life, Environmental and Earth Sciences Division, Research Institute of the University of Bucharest (ICUB), 91-95 Splaiul Independentei, Bucharest 050095, Romania
| | - Florin Bogdan Epureanu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, Bucharest 050095, Romania; Life, Environmental and Earth Sciences Division, Research Institute of the University of Bucharest (ICUB), 91-95 Splaiul Independentei, Bucharest 050095, Romania
| | - Stefan A Mann
- Cytocentrics Bioscience GmbH, Nattermannallee 1, 50829 Cologne, Germany
| | - Thomas Knott
- CytoBioScience Inc., 3463 Magic Drive, San Antonio, TX 78229, USA
| | - Beatrice Mihaela Radu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, Bucharest 050095, Romania; Life, Environmental and Earth Sciences Division, Research Institute of the University of Bucharest (ICUB), 91-95 Splaiul Independentei, Bucharest 050095, Romania
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Ozturk N, Uslu S, Ozdemir S. Diabetes-induced changes in cardiac voltage-gated ion channels. World J Diabetes 2021; 12:1-18. [PMID: 33520105 PMCID: PMC7807254 DOI: 10.4239/wjd.v12.i1.1] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 11/05/2020] [Accepted: 11/13/2020] [Indexed: 02/06/2023] Open
Abstract
Diabetes mellitus affects the heart through various mechanisms such as microvascular defects, metabolic abnormalities, autonomic dysfunction and incompatible immune response. Furthermore, it can also cause functional and structural changes in the myocardium by a disease known as diabetic cardiomyopathy (DCM) in the absence of coronary artery disease. As DCM progresses it causes electrical remodeling of the heart, left ventricular dysfunction and heart failure. Electrophysiological changes in the diabetic heart contribute significantly to the incidence of arrhythmias and sudden cardiac death in diabetes mellitus patients. In recent studies, significant changes in repolarizing K+ currents, Na+ currents and L-type Ca2+ currents along with impaired Ca2+ homeostasis and defective contractile function have been identified in the diabetic heart. In addition, insulin levels and other trophic factors change significantly to maintain the ionic channel expression in diabetic patients. There are many diagnostic tools and management options for DCM, but it is difficult to detect its development and to effectively prevent its progress. In this review, diabetes-associated alterations in voltage-sensitive cardiac ion channels are comprehensively assessed to understand their potential role in the pathophysiology and pathogenesis of DCM.
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Affiliation(s)
- Nihal Ozturk
- Department of Biophysics, Akdeniz University Faculty of Medicine, Antalya 07058, Turkey
| | - Serkan Uslu
- Department of Biophysics, Akdeniz University Faculty of Medicine, Antalya 07058, Turkey
| | - Semir Ozdemir
- Department of Biophysics, Akdeniz University Faculty of Medicine, Antalya 07058, Turkey
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Hilderink S, Devalla HD, Bosch L, Wilders R, Verkerk AO. Ultrarapid Delayed Rectifier K + Channelopathies in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes. Front Cell Dev Biol 2020; 8:536. [PMID: 32850774 PMCID: PMC7399090 DOI: 10.3389/fcell.2020.00536] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 06/08/2020] [Indexed: 12/12/2022] Open
Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia. About 5-15% of AF patients have a mutation in a cardiac gene, including mutations in KCNA5, encoding the Kv1.5 α-subunit of the ion channel carrying the atrial-specific ultrarapid delayed rectifier K+ current (IKur). Both loss-of-function and gain-of-function AF-related mutations in KCNA5 are known, but their effects on action potentials (APs) of human cardiomyocytes have been poorly studied. Here, we assessed the effects of wild-type and mutant IKur on APs of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). We found that atrial-like hiPSC-CMs, generated by a retinoic acid-based differentiation protocol, have APs with faster repolarization compared to ventricular-like hiPSC-CMs, resulting in shorter APs with a lower AP plateau. Native IKur, measured as current sensitive to 50 μM 4-aminopyridine, was 1.88 ± 0.49 (mean ± SEM, n = 17) and 0.26 ± 0.26 pA/pF (n = 17) in atrial- and ventricular-like hiPSC-CMs, respectively. In both atrial- and ventricular-like hiPSC-CMs, IKur blockade had minimal effects on AP parameters. Next, we used dynamic clamp to inject various amounts of a virtual IKur, with characteristics as in freshly isolated human atrial myocytes, into 11 atrial-like and 10 ventricular-like hiPSC-CMs, in which native IKur was blocked. Injection of IKur with 100% density shortened the APs, with its effect being strongest on the AP duration at 20% repolarization (APD20) of atrial-like hiPSC-CMs. At IKur densities < 100% (compared to 100%), simulating loss-of-function mutations, significant AP prolongation and raise of plateau were observed. At IKur densities > 100%, simulating gain-of-function mutations, APD20 was decreased in both atrial- and ventricular-like hiPSC-CMs, but only upon a strong increase in IKur. In ventricular-like hiPSC-CMs, lowering of the plateau resulted in AP shortening. We conclude that a decrease in IKur, mimicking loss-of-function mutations, has a stronger effect on the AP of hiPSC-CMs than an increase, mimicking gain-of-function mutations, whereas in ventricular-like hiPSC-CMs such increase results in AP shortening, causing their AP morphology to become more atrial-like. Effects of native IKur modulation on atrial-like hiPSC-CMs are less pronounced than effects of virtual IKur injection because IKur density of atrial-like hiPSC-CMs is substantially smaller than that of freshly isolated human atrial myocytes.
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Affiliation(s)
- Sarah Hilderink
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Harsha D Devalla
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Leontien Bosch
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Ronald Wilders
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Arie O Verkerk
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands.,Department of Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
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Houston C, Marchand B, Engelbert L, Cantwell CD. Reducing complexity and unidentifiability when modelling human atrial cells. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2020. [PMID: 32448063 DOI: 10.5061/dryad.p2ngf1vmc] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Mathematical models of a cellular action potential (AP) in cardiac modelling have become increasingly complex, particularly in gating kinetics, which control the opening and closing of individual ion channel currents. As cardiac models advance towards use in personalized medicine to inform clinical decision-making, it is critical to understand the uncertainty hidden in parameter estimates from their calibration to experimental data. This study applies approximate Bayesian computation to re-calibrate the gating kinetics of four ion channels in two existing human atrial cell models to their original datasets, providing a measure of uncertainty and indication of potential issues with selecting a single unique value given the available experimental data. Two approaches are investigated to reduce the uncertainty present: re-calibrating the models to a more complete dataset and using a less complex formulation with fewer parameters to constrain. The re-calibrated models are inserted back into the full cell model to study the overall effect on the AP. The use of more complete datasets does not eliminate uncertainty present in parameter estimates. The less complex model, particularly for the fast sodium current, gave a better fit to experimental data alongside lower parameter uncertainty and improved computational speed. This article is part of the theme issue 'Uncertainty quantification in cardiac and cardiovascular modelling and simulation'.
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Affiliation(s)
- C Houston
- ElectroCardioMaths Programme, Centre for Cardiac Engineering, Imperial College, London, UK
- Department of Aeronautics, Imperial College, London, UK
| | - B Marchand
- Department of Aeronautics, Imperial College, London, UK
| | - L Engelbert
- Department of Aeronautics, Imperial College, London, UK
| | - C D Cantwell
- ElectroCardioMaths Programme, Centre for Cardiac Engineering, Imperial College, London, UK
- Department of Aeronautics, Imperial College, London, UK
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Houston C, Marchand B, Engelbert L, Cantwell CD. Reducing complexity and unidentifiability when modelling human atrial cells. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2020; 378:20190339. [PMID: 32448063 PMCID: PMC7287336 DOI: 10.1098/rsta.2019.0339] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Mathematical models of a cellular action potential (AP) in cardiac modelling have become increasingly complex, particularly in gating kinetics, which control the opening and closing of individual ion channel currents. As cardiac models advance towards use in personalized medicine to inform clinical decision-making, it is critical to understand the uncertainty hidden in parameter estimates from their calibration to experimental data. This study applies approximate Bayesian computation to re-calibrate the gating kinetics of four ion channels in two existing human atrial cell models to their original datasets, providing a measure of uncertainty and indication of potential issues with selecting a single unique value given the available experimental data. Two approaches are investigated to reduce the uncertainty present: re-calibrating the models to a more complete dataset and using a less complex formulation with fewer parameters to constrain. The re-calibrated models are inserted back into the full cell model to study the overall effect on the AP. The use of more complete datasets does not eliminate uncertainty present in parameter estimates. The less complex model, particularly for the fast sodium current, gave a better fit to experimental data alongside lower parameter uncertainty and improved computational speed. This article is part of the theme issue 'Uncertainty quantification in cardiac and cardiovascular modelling and simulation'.
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Affiliation(s)
- C. Houston
- ElectroCardioMaths Programme, Centre for Cardiac Engineering, Imperial College, London, UK
- Department of Aeronautics, Imperial College, London, UK
- e-mail:
| | - B. Marchand
- Department of Aeronautics, Imperial College, London, UK
| | - L. Engelbert
- Department of Aeronautics, Imperial College, London, UK
| | - C. D. Cantwell
- ElectroCardioMaths Programme, Centre for Cardiac Engineering, Imperial College, London, UK
- Department of Aeronautics, Imperial College, London, UK
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33
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Williams EA, Russo V, Ceraso S, Gupta D, Barrett-Jolley R. Anti-arrhythmic properties of non-antiarrhythmic medications. Pharmacol Res 2020; 156:104762. [PMID: 32217149 PMCID: PMC7248574 DOI: 10.1016/j.phrs.2020.104762] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 03/10/2020] [Accepted: 03/17/2020] [Indexed: 02/06/2023]
Abstract
Traditional anti-arrhythmic drugs are classified by the Vaughan-Williams classification scheme based on their mechanisms of action, which includes effects on receptors and/or ion channels. Some known anti-arrhythmic drugs do not perfectly fit into this classification scheme. Other medications/molecules with established non-anti-arrhythmic indications have shown anti-arrhythmic properties worth exploring. In this narrative review, we discuss the molecular mechanisms and evidence base for the anti-arrhythmic properties of traditional non-antiarrhythmic drugs such as inhibitors of the renin angiotensin system (RAS), statins and polyunsaturated fatty acids (PUFAs). In summary, RAS antagonists, statins and PUFAs are 'upstream target modulators' that appear to have anti-arrhythmic roles. RAS blockers prevent the downstream arrhythmogenic effects of angiotensin II - the main effector peptide of RAS - and the angiotensin type 1 receptor. Statins have pleiotropic effects including anti-inflammatory, immunomodulatory, modulation of autonomic nervous system, anti-proliferative and anti-oxidant actions which appear to underlie their anti-arrhythmic properties. PUFAs have the ability to alter ion channel function and prevent excessive accumulation of calcium ions in cardiac myocytes, which might explain their benefits in certain arrhythmic conditions. Clearly, whilst a number of anti-arrhythmic drugs exist, there is still a need for randomised trials to establish whether additional agents, including those already in clinical use, have significant anti-arrhythmic effects.
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Affiliation(s)
- Emmanuel Ato Williams
- Department of Cardiology, Liverpool Heart and Chest Hospital, Thomas Drive, Liverpool, L14 3PE, United Kingdom; Institute of Aging and Chronic Disease, University of Liverpool, United Kingdom
| | - Vincenzo Russo
- Chair of Cardiology, Department of Medical Translational Sciences, University of Campania "Luigi Vanvitelli", Monaldi Hospital, Naples, Italy
| | - Sergio Ceraso
- Specialization Fellow in Cardiology, Department of Medical Translational Sciences, University of Campania "Luigi Vanvitelli" - Monaldi Hospital, Naples, Italy
| | - Dhiraj Gupta
- Department of Cardiology, Liverpool Heart and Chest Hospital, Thomas Drive, Liverpool, L14 3PE, United Kingdom
| | - Richard Barrett-Jolley
- Chair Neuropharmacology, Institute of Aging and Chronic Disease, University of Liverpool, United Kingdom.
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Milton AO, Wang T, Li W, Guo J, Zhang S. Mechanical stretch increases Kv1.5 current through an interaction between the S1-S2 linker and N-terminus of the channel. J Biol Chem 2020; 295:4723-4732. [PMID: 32122972 DOI: 10.1074/jbc.ra119.011302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 02/27/2020] [Indexed: 11/06/2022] Open
Abstract
The voltage-gated potassium channel Kv1.5 plays important roles in atrial repolarization and regulation of vascular tone. In the present study, we investigated the effects of mechanical stretch on Kv1.5 channels. We induced mechanical stretch by centrifuging or culturing Kv1.5-expressing HEK 293 cells and neonatal rat ventricular myocytes in low osmolarity (LO) medium and then recorded Kv1.5 current (IKv1.5) in a normal, isotonic solution. We observed that mechanical stretch increased IKv1.5, and this increase required the intact, long, proline-rich extracellular S1-S2 linker of the Kv1.5 channel. The low osmolarity-induced IKv1.5 increase also required an intact intracellular N terminus, which contains the binding motif for endogenous Src tyrosine kinase that constitutively inhibits IKv1.5 Disrupting the Src-binding motif of Kv1.5 through N-terminal truncation or mutagenesis abolished the mechanical stretch-mediated increase in IKv1.5 Our results further showed that the extracellular S1-S2 linker of Kv1.5 communicates with the intracellular N terminus. Although the S1-S2 linker of WT Kv1.5 could be cleaved by extracellularly applied proteinase K (PK), an N-terminal truncation up to amino acid residue 209 altered the conformation of the S1-S2 linker and made it no longer susceptible to proteinase K-mediated cleavage. In summary, the findings of our study indicate that the S1-S2 linker of Kv1.5 represents a mechanosensor that regulates the activity of this channel. By targeting the S1-S2 linker, mechanical stretch may induce a change in the N-terminal conformation of Kv1.5 that relieves Src-mediated tonic channel inhibition and results in an increase in IKv1.5.
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Affiliation(s)
- Alexandria O Milton
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Tingzhong Wang
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Wentao Li
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Jun Guo
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Shetuan Zhang
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada
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How the Deuteration of Dronedarone Can Modify Its Cardiovascular Profile: In Vivo Characterization of Electropharmacological Effects of Poyendarone, a Deuterated Analogue of Dronedarone. Cardiovasc Toxicol 2020; 20:339-350. [PMID: 31898152 DOI: 10.1007/s12012-019-09559-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Since deuterium replacement has a potential to modulate pharmacodynamics, pharmacokinetics and toxicity, we developed deuterated dronedarone; poyendarone, and assessed its cardiovascular effects. Poyendarone hydrochloride in doses of 0.3 and 3 mg/kg over 30 s was intravenously administered to the halothane-anesthetized dogs (n = 4), which provided peak plasma concentrations of 108 ± 10 and 1120 ± 285 ng/mL, respectively. The 0.3 mg/kg shortened the ventricular repolarization period. The 3 mg/kg transiently increased the heart rate at 5 min but decreased at 45 min, and elevated the total peripheral vascular resistance and left ventricular preload, whereas it reduced the mean blood pressure at 5 min, left ventricular contractility and cardiac output. The transient tachycardic action is considered to be induced by the hypotension-induced, reflex-mediated increase of sympathetic tone. The 3 mg/kg delayed both intra-atrial and intra-ventricular conductions, indicating Na+ channel inhibitory action. Moreover, the 3 mg/kg transiently shortened the ventricular repolarization period at 5 min. No significant change was detected in the late repolarization by poyendarone, indicating it might not hardly significantly alter rapidly activating delayed-rectifier K+ current (IKr). Poyendarone prolonged the atrial effective refractory period greater than the ventricular parameter. When compared with dronedarone, poyendarone showed similar pharmacokinetics of dronedarone, but reduced β-adrenoceptor blocking activity as well as the cardio-suppressive effect. Poyendarone failed to inhibit IKr and showed higher atrial selectivity in prolonging the effective refractory period of atrium versus ventricle. Thus, the deuteration may be an effective way to improve the cardiovascular profile of dronedarone. Poyendarone is a promising anti-atrial fibrillatory drug candidate.
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36
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Zhang Y, Du W, Yang B. Long non-coding RNAs as new regulators of cardiac electrophysiology and arrhythmias: Molecular mechanisms, therapeutic implications and challenges. Pharmacol Ther 2019; 203:107389. [DOI: 10.1016/j.pharmthera.2019.06.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 06/27/2019] [Indexed: 12/21/2022]
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37
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Devalla HD, Passier R. Cardiac differentiation of pluripotent stem cells and implications for modeling the heart in health and disease. Sci Transl Med 2019; 10:10/435/eaah5457. [PMID: 29618562 DOI: 10.1126/scitranslmed.aah5457] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 07/15/2016] [Accepted: 06/20/2017] [Indexed: 12/21/2022]
Abstract
Cellular models comprising cardiac cell types derived from human pluripotent stem cells are valuable for studying heart development and disease. We discuss transcriptional differences that define cellular identity in the heart, current methods for generating different cardiomyocyte subtypes, and implications for disease modeling, tissue engineering, and regenerative medicine.
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Affiliation(s)
- Harsha D Devalla
- Department of Anatomy and Embryology, Leiden University Medical Center, 2333 ZC Leiden, Netherlands.
| | - Robert Passier
- Department of Anatomy and Embryology, Leiden University Medical Center, 2333 ZC Leiden, Netherlands. .,Department of Applied Stem Cell Technologies, Technical Medical Center, University of Twente, 7500 AE Enschede, Netherlands
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38
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Lamothe SM, Hogan-Cann AE, Li W, Guo J, Yang T, Tschirhart JN, Zhang S. The N terminus and transmembrane segment S1 of Kv1.5 can coassemble with the rest of the channel independently of the S1-S2 linkage. J Biol Chem 2018; 293:15347-15358. [PMID: 30121572 DOI: 10.1074/jbc.ra118.004065] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 08/14/2018] [Indexed: 11/06/2022] Open
Abstract
The voltage-gated potassium channel Kv1.5 belongs to the Shaker superfamily. Kv1.5 is composed of four subunits, each comprising 613 amino acids, which make up the N terminus, six transmembrane segments (S1-S6), and the C terminus. We recently demonstrated that, in HEK cells, extracellularly applied proteinase K (PK) cleaves Kv1.5 channels at a single site in the S1-S2 linker. This cleavage separates Kv1.5 into an N-fragment (N terminus to S1) and a C-fragment (S2 to C terminus). Interestingly, the cleavage does not impair channel function. Here, we investigated the role of the N terminus and S1 in Kv1.5 expression and function by creating plasmids encoding various fragments, including those that mimic PK-cleaved products. Our results disclosed that although expression of the pore-containing fragment (Frag(304-613)) alone could not produce current, coexpression with Frag(1-303) generated a functional channel. Immunofluorescence and biotinylation analyses uncovered that Frag(1-303) was required for Frag(304-613) to traffic to the plasma membrane. Biochemical analysis revealed that the two fragments interacted throughout channel trafficking and maturation. In Frag(1-303)+(304-613)-coassembled channels, which lack a covalent linkage between S1 and S2, amino acid residues 1-209 were important for association with Frag(304-613), and residues 210-303 were necessary for mediating trafficking of coassembled channels to the plasma membrane. We conclude that the N terminus and S1 of Kv1.5 can attract and coassemble with the rest of the channel (i.e. Frag(304-613)) to form a functional channel independently of the S1-S2 linkage.
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Affiliation(s)
- Shawn M Lamothe
- From the Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Aja E Hogan-Cann
- From the Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Wentao Li
- From the Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Jun Guo
- From the Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Tonghua Yang
- From the Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Jared N Tschirhart
- From the Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Shetuan Zhang
- From the Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada
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39
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Malki G, Zlochiver S. Cardiac spiral wave drifting due to spatial temperature gradients - A numerical study. Med Eng Phys 2018; 61:69-80. [PMID: 30201284 DOI: 10.1016/j.medengphy.2018.08.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 06/16/2018] [Accepted: 08/26/2018] [Indexed: 01/07/2023]
Abstract
Cardiac rotors are believed to be a major driver source of persistent atrial fibrillation (AF), and their spatiotemporal characterization is essential for successful ablation procedures. However, electrograms guided ablation have not been proven to have benefit over empirical ablation thus far, and there is a strong need of improving the localization of cardiac arrhythmogenic targets for ablation. A new approach for characterize rotors is proposed that is based on induced spatial temperature gradients (STGs), and investigated by theoretical study using numerical simulations. We hypothesize that such gradients will cause rotor drifting due to induced spatial heterogeneity in excitability, so that rotors could be driven towards the ablating probe. Numerical simulations were conducted in single cell and 2D atrial models using AF remodeled kinetics. STGs were applied either linearly on the entire tissue or as a small local perturbation, and the major ion channel rate constants were adjusted following Arrhenius equation. In the AF-remodeled single cell, recovery time increased exponentially with decreasing temperatures, despite the marginal effect of temperature on the action potential duration. In 2D models, spiral waves drifted with drifting velocity components affected by both temperature gradient direction and the spiral wave rotation direction. Overall, spiral waves drifted towards the colder tissue region associated with global minimum of excitability. A local perturbation with a temperature of T = 28 °C was found optimal for spiral wave attraction for the studied conditions. This work provides a preliminary proof-of-concept for a potential prospective technique for rotor attraction. We envision that the insights from this study will be utilize in the future in the design of a new methodology for AF characterization and termination during ablation procedures.
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Affiliation(s)
- Guy Malki
- Department of Biomedical Engineering, Faculty of Engineering, Tel-Aviv University, Ramat-Aviv, Tel-Aviv 69978, Israel
| | - Sharon Zlochiver
- Department of Biomedical Engineering, Faculty of Engineering, Tel-Aviv University, Ramat-Aviv, Tel-Aviv 69978, Israel.
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40
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Rashid MH, Kuyucak S. Computational Study of the Loss-of-Function Mutations in the Kv1.5 Channel Associated with Atrial Fibrillation. ACS OMEGA 2018; 3:8882-8890. [PMID: 31459020 PMCID: PMC6645308 DOI: 10.1021/acsomega.8b01094] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 07/31/2018] [Indexed: 06/10/2023]
Abstract
Atrial fibrillation (AF) is a heart disease caused by defective ion channels in the atria, which affect the action potential (AP) duration and disturb normal heart rhythm. Rapid firing of APs in neighboring atrial cells is a common mechanism of AF, and therefore, therapeutic approaches have focused on extending the AP duration by inhibiting the K+ channels involved in repolarization. Of these, Kv1.5 that carries the I Kur current is a promising target because it is expressed mainly in atria and not in ventricles. In genetic studies of AF patients, both loss-of-function and gain-of-function mutations in Kv1.5 have been identified, indicating that either decreased or increased I Kur currents could trigger AF. Blocking of already downregulated Kv1.5 channels could cause AF to become chronic. Thus, a molecular-level understanding of how the loss-of-function mutations in Kv1.5 affect I Kur would be useful for developing new therapeutics. Here, we perform molecular dynamics simulations to study the effect of three loss-of-function mutations in the pore domain of Kv1.5 on ion permeation. Comparison of the pore structures and ion free energies in the wild-type and mutant Kv1.5 channels indicates that conformational changes in the selectivity filter could hinder ion permeation in the mutant channels.
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Affiliation(s)
- Md Harunur Rashid
- Department of Chemistry,
Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
- School of Engineering, RMIT University, Melbourne, Victoria 3000, Australia
| | - Serdar Kuyucak
- School of Physics, University of Sydney, Sydney, New South Wales 2006, Australia
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Calvo D, Filgueiras-Rama D, Jalife J. Mechanisms and Drug Development in Atrial Fibrillation. Pharmacol Rev 2018; 70:505-525. [PMID: 29921647 PMCID: PMC6010660 DOI: 10.1124/pr.117.014183] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation is a highly prevalent cardiac arrhythmia and the most important cause of embolic stroke. Although genetic studies have identified an increasing assembly of AF-related genes, the impact of these genetic discoveries is yet to be realized. In addition, despite more than a century of research and speculation, the molecular and cellular mechanisms underlying AF have not been established, and therapy for AF, particularly persistent AF, remains suboptimal. Current antiarrhythmic drugs are associated with a significant rate of adverse events, particularly proarrhythmia, which may explain why many highly symptomatic AF patients are not receiving any rhythm control therapy. This review focuses on recent advances in AF research, including its epidemiology, genetics, and pathophysiological mechanisms. We then discuss the status of antiarrhythmic drug therapy for AF today, reviewing molecular mechanisms, and the possible clinical use of some of the new atrial-selective antifibrillatory agents, as well as drugs that target atrial remodeling, inflammation and fibrosis, which are being tested as upstream therapies to prevent AF perpetuation. Altogether, the objective is to highlight the magnitude and endemic dimension of AF, which requires a significant effort to develop new and effective antiarrhythmic drugs, but also improve AF prevention and treatment of risk factors that are associated with AF complications.
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Affiliation(s)
- David Calvo
- Department of Cardiology, Arrhythmia Unit, Hospital Universitario Central de Asturias and Instituto de Investigación Sanitaria del Principado de Asturias, Oviedo, Spain (D.C.); Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain (D.F.-R., J.J.); Department of Cardiology, Arrhythmia Unit, Hospital Clínico Universitario San Carlos, Madrid, Spain (D.F.-R.); Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain (D.F.-R., J.J.); and Center for Arrhythmia Research, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan (J.J.)
| | - David Filgueiras-Rama
- Department of Cardiology, Arrhythmia Unit, Hospital Universitario Central de Asturias and Instituto de Investigación Sanitaria del Principado de Asturias, Oviedo, Spain (D.C.); Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain (D.F.-R., J.J.); Department of Cardiology, Arrhythmia Unit, Hospital Clínico Universitario San Carlos, Madrid, Spain (D.F.-R.); Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain (D.F.-R., J.J.); and Center for Arrhythmia Research, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan (J.J.)
| | - José Jalife
- Department of Cardiology, Arrhythmia Unit, Hospital Universitario Central de Asturias and Instituto de Investigación Sanitaria del Principado de Asturias, Oviedo, Spain (D.C.); Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain (D.F.-R., J.J.); Department of Cardiology, Arrhythmia Unit, Hospital Clínico Universitario San Carlos, Madrid, Spain (D.F.-R.); Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain (D.F.-R., J.J.); and Center for Arrhythmia Research, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan (J.J.)
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Cyganek L, Tiburcy M, Sekeres K, Gerstenberg K, Bohnenberger H, Lenz C, Henze S, Stauske M, Salinas G, Zimmermann WH, Hasenfuss G, Guan K. Deep phenotyping of human induced pluripotent stem cell-derived atrial and ventricular cardiomyocytes. JCI Insight 2018; 3:99941. [PMID: 29925689 DOI: 10.1172/jci.insight.99941] [Citation(s) in RCA: 182] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 05/17/2018] [Indexed: 12/20/2022] Open
Abstract
Generation of homogeneous populations of subtype-specific cardiomyocytes (CMs) derived from human induced pluripotent stem cells (iPSCs) and their comprehensive phenotyping is crucial for a better understanding of the subtype-related disease mechanisms and as tools for the development of chamber-specific drugs. The goals of this study were to apply a simple and efficient method for differentiation of iPSCs into defined functional CM subtypes in feeder-free conditions and to obtain a comprehensive understanding of the molecular, cell biological, and functional properties of atrial and ventricular iPSC-CMs on both the single-cell and engineered heart muscle (EHM) level. By a stage-specific activation of retinoic acid signaling in monolayer-based and well-defined culture, we showed that cardiac progenitors can be directed towards a highly homogeneous population of atrial CMs. By combining the transcriptome and proteome profiling of the iPSC-CM subtypes with functional characterizations via optical action potential and calcium imaging, and with contractile analyses in EHM, we demonstrated that atrial and ventricular iPSC-CMs and -EHM highly correspond to the atrial and ventricular heart muscle, respectively. This study provides a comprehensive understanding of the molecular and functional identities characteristic of atrial and ventricular iPSC-CMs and -EHM and supports their suitability in disease modeling and chamber-specific drug screening.
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Affiliation(s)
- Lukas Cyganek
- Clinic for Cardiology and Pneumology, University Medical Center Göttingen (UMG), Göttingen, Germany.,DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
| | - Malte Tiburcy
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany.,Institute of Pharmacology and Toxicology, UMG, Göttingen, Germany
| | - Karolina Sekeres
- Institute of Pharmacology and Toxicology, Technische Universität Dresden, Dresden, Germany
| | - Kathleen Gerstenberg
- Clinic for Cardiology and Pneumology, University Medical Center Göttingen (UMG), Göttingen, Germany
| | | | - Christof Lenz
- Institute for Clinical Chemistry, UMG, Göttingen, Germany.,Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Sarah Henze
- Clinic for Cardiology and Pneumology, University Medical Center Göttingen (UMG), Göttingen, Germany
| | - Michael Stauske
- Clinic for Cardiology and Pneumology, University Medical Center Göttingen (UMG), Göttingen, Germany.,DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
| | - Gabriela Salinas
- Transcriptome and Genome Analysis Laboratory Core Unit, UMG, Göttingen, Germany
| | - Wolfram-Hubertus Zimmermann
- DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany.,Institute of Pharmacology and Toxicology, UMG, Göttingen, Germany
| | - Gerd Hasenfuss
- Clinic for Cardiology and Pneumology, University Medical Center Göttingen (UMG), Göttingen, Germany.,DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany
| | - Kaomei Guan
- Clinic for Cardiology and Pneumology, University Medical Center Göttingen (UMG), Göttingen, Germany.,DZHK (German Center for Cardiovascular Research), partner site Göttingen, Germany.,Institute of Pharmacology and Toxicology, Technische Universität Dresden, Dresden, Germany
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Martinez-Mateu L, Romero L, Ferrer-Albero A, Sebastian R, Rodríguez Matas JF, Jalife J, Berenfeld O, Saiz J. Factors affecting basket catheter detection of real and phantom rotors in the atria: A computational study. PLoS Comput Biol 2018; 14:e1006017. [PMID: 29505583 PMCID: PMC5854439 DOI: 10.1371/journal.pcbi.1006017] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 03/15/2018] [Accepted: 02/01/2018] [Indexed: 02/07/2023] Open
Abstract
Anatomically based procedures to ablate atrial fibrillation (AF) are often successful in terminating paroxysmal AF. However, the ability to terminate persistent AF remains disappointing. New mechanistic approaches use multiple-electrode basket catheter mapping to localize and target AF drivers in the form of rotors but significant concerns remain about their accuracy. We aimed to evaluate how electrode-endocardium distance, far-field sources and inter-electrode distance affect the accuracy of localizing rotors. Sustained rotor activation of the atria was simulated numerically and mapped using a virtual basket catheter with varying electrode densities placed at different positions within the atrial cavity. Unipolar electrograms were calculated on the entire endocardial surface and at each of the electrodes. Rotors were tracked on the interpolated basket phase maps and compared with the respective atrial voltage and endocardial phase maps, which served as references. Rotor detection by the basket maps varied between 35-94% of the simulation time, depending on the basket's position and the electrode-to-endocardial wall distance. However, two different types of phantom rotors appeared also on the basket maps. The first type was due to the far-field sources and the second type was due to interpolation between the electrodes; increasing electrode density decreased the incidence of the second but not the first type of phantom rotors. In the simulations study, basket catheter-based phase mapping detected rotors even when the basket was not in full contact with the endocardial wall, but always generated a number of phantom rotors in the presence of only a single real rotor, which would be the desired ablation target. Phantom rotors may mislead and contribute to failure in AF ablation procedures.
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Affiliation(s)
- Laura Martinez-Mateu
- Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, Valencia, Spain
| | - Lucia Romero
- Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, Valencia, Spain
| | - Ana Ferrer-Albero
- Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, Valencia, Spain
| | - Rafael Sebastian
- Computational Multiscale Simulation Lab, Department of Computer Science, Universitat de València, Valencia, Spain
| | - José F. Rodríguez Matas
- Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano, Milano, Italy
| | - José Jalife
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, United States of America
- Fundación Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
- CIBER of Cardiovascular Diseases, Madrid, Spain
| | - Omer Berenfeld
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Javier Saiz
- Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, Valencia, Spain
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A double-blind, randomised, placebo-controlled, cross-over study assessing the use of XEN-D0103 in patients with paroxysmal atrial fibrillation and implanted pacemakers allowing continuous beat-to-beat monitoring of drug efficacy. J Interv Card Electrophysiol 2018; 51:191-197. [PMID: 29460236 DOI: 10.1007/s10840-018-0318-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Accepted: 01/24/2018] [Indexed: 01/21/2023]
Abstract
PURPOSE The ultrarapid delayed rectifier current (IKur) carried by Kv1.5 channels, which are solely expressed in the atrium, is a potential target for safer treatment of paroxysmal atrial fibrillation (PAF). XEN-D0103 is a nanomolar ion channel blocker that selectively inhibits potassium ion flux through the Kv1.5 ion channel. The efficacy of XEN-D0103 in reducing AF burden was assessed in patients with DDDRp permanent pacemakers (PPMs) and PAF. METHODS A double-blind, placebo-controlled, cross-over study was performed in patients with PAF and DDDRp PPMs with advanced atrial and ventricular Holters allowing beat-to-beat arrhythmia follow-up. All anti-arrhythmic drugs were withdrawn before randomised treatment. After baseline assessment, patients were randomly assigned to two treatment periods of placebo then XEN-D0103 50 mg bd, or XEN-D0103 50 mg bd then placebo. RESULTS Fifty-four patients were screened and 21 patients were eligible and included in the randomised trial. All 21 patients completed both treatment periods. The primary endpoint was change in AF burden assessed by PPM. There was no significant difference in AF burden on treatment with XEN-D0103 versus placebo. There was a reduction in the mean frequency of AF episodes (relative reduction 0.72, 95% CI 0.66 to 0.77; p < 0.0001). XEN-D0103 was safe and well tolerated, and there were no serious adverse events. XEN-D0103 did not have any apparent effect on heart rate compared to placebo. CONCLUSIONS XEN-D0103 did not reduce AF burden in patients with PAF and dual chamber pacemakers providing beat-to-beat monitoring. XEN-D0103 was well tolerated and did not have any apparent effect on heart rate. Although single-ion channel blockade with XEN-D0103 did not affect AF in this study, there might be a potential for this agent to be used in combination with other atrially specific drugs in the treatment of AF. EUDRACT TRIAL REGISTRATION NUMBER 2013-004456-38.
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45
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Interactions of Propofol With Human Voltage-gated Kv1.5 Channel Determined by Docking Simulation and Mutagenesis Analyses. J Cardiovasc Pharmacol 2018; 71:10-18. [DOI: 10.1097/fjc.0000000000000538] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Muszkiewicz A, Liu X, Bueno-Orovio A, Lawson BAJ, Burrage K, Casadei B, Rodriguez B. From ionic to cellular variability in human atrial myocytes: an integrative computational and experimental study. Am J Physiol Heart Circ Physiol 2017; 314:H895-H916. [PMID: 29351467 PMCID: PMC6008144 DOI: 10.1152/ajpheart.00477.2017] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Variability refers to differences in physiological function between individuals, which may translate into different disease susceptibility and treatment efficacy. Experiments in human cardiomyocytes face wide variability and restricted tissue access; under these conditions, computational models are a useful complementary tool. We conducted a computational and experimental investigation in cardiomyocytes isolated from samples of the right atrial appendage of patients undergoing cardiac surgery to evaluate the impact of variability in action potentials (APs) and subcellular ionic densities on Ca2+ transient dynamics. Results showed that 1) variability in APs and ionic densities is large, even within an apparently homogenous patient cohort, and translates into ±100% variation in ionic conductances; 2) experimentally calibrated populations of models with wide variations in ionic densities yield APs overlapping with those obtained experimentally, even if AP characteristics of the original generic model differed significantly from experimental APs; 3) model calibration with AP recordings restricts the variability in ionic densities affecting upstroke and resting potential, but redundancy in repolarization currents admits substantial variability in ionic densities; and 4) model populations constrained with experimental APs and ionic densities exhibit three Ca2+ transient phenotypes, differing in intracellular Ca2+ handling and Na+/Ca2+ membrane extrusion. These findings advance our understanding of the impact of variability in human atrial electrophysiology. NEW & NOTEWORTHY Variability in human atrial electrophysiology is investigated by integrating for the first time cellular-level and ion channel recordings in computational electrophysiological models. Ion channel calibration restricts current densities but not cellular phenotypic variability. Reduced Na+/Ca2+ exchanger is identified as a primary mechanism underlying diastolic Ca2+ fluctuations in human atrial myocytes.
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Affiliation(s)
- Anna Muszkiewicz
- Department of Computer Science, University of Oxford , Oxford , United Kingdom
| | - Xing Liu
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital , Oxford , United Kingdom
| | | | - Brodie A J Lawson
- ARC Centre of Excellence for Mathematical and Statistical Frontiers, School of Mathematical Sciences, Queensland University of Technology , Brisbane, Queensland , Australia.,School of Mathematics, Queensland University of Technology , Brisbane, Queensland , Australia
| | - Kevin Burrage
- Department of Computer Science, University of Oxford , Oxford , United Kingdom.,ARC Centre of Excellence for Mathematical and Statistical Frontiers, School of Mathematical Sciences, Queensland University of Technology , Brisbane, Queensland , Australia.,School of Mathematics, Queensland University of Technology , Brisbane, Queensland , Australia
| | - Barbara Casadei
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital , Oxford , United Kingdom
| | - Blanca Rodriguez
- Department of Computer Science, University of Oxford , Oxford , United Kingdom
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47
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Balse E, Boycott HE. Ion Channel Trafficking: Control of Ion Channel Density as a Target for Arrhythmias? Front Physiol 2017; 8:808. [PMID: 29089904 PMCID: PMC5650974 DOI: 10.3389/fphys.2017.00808] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 10/02/2017] [Indexed: 12/20/2022] Open
Abstract
The shape of the cardiac action potential (AP) is determined by the contributions of numerous ion channels. Any dysfunction in the proper function or expression of these ion channels can result in a change in effective refractory period (ERP) and lead to arrhythmia. The processes underlying the correct targeting of ion channels to the plasma membrane are complex, and have not been fully characterized in cardiac myocytes. Emerging evidence highlights ion channel trafficking as a potential causative factor in certain acquired and inherited arrhythmias, and therapies which target trafficking as opposed to pore block are starting to receive attention. In this review we present the current evidence for the mechanisms which underlie precise control of cardiac ion channel trafficking and targeting.
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Affiliation(s)
- Elise Balse
- Unité de Recherche sur les Maladies Cardiovasculaires, le Métabolisme et la Nutrition, Faculté de Médecine Pitié-Salpêtrière, Sorbonne Universités, UPMC Univ. Paris VI, Inserm, UMRS 1166, Université Pierre et Marie Curie, Paris, France
| | - Hannah E. Boycott
- Department of Cardiovascular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
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48
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McKeithan WL, Savchenko A, Yu MS, Cerignoli F, Bruyneel AAN, Price JH, Colas AR, Miller EW, Cashman JR, Mercola M. An Automated Platform for Assessment of Congenital and Drug-Induced Arrhythmia with hiPSC-Derived Cardiomyocytes. Front Physiol 2017; 8:766. [PMID: 29075196 PMCID: PMC5641590 DOI: 10.3389/fphys.2017.00766] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Accepted: 09/19/2017] [Indexed: 12/12/2022] Open
Abstract
The ability to produce unlimited numbers of human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs) harboring disease and patient-specific gene variants creates a new paradigm for modeling congenital heart diseases (CHDs) and predicting proarrhythmic liabilities of drug candidates. However, a major roadblock to implementing hiPSC-CM technology in drug discovery is that conventional methods for monitoring action potential (AP) kinetics and arrhythmia phenotypes in vitro have been too costly or technically challenging to execute in high throughput. Herein, we describe the first large-scale, fully automated and statistically robust analysis of AP kinetics and drug-induced proarrhythmia in hiPSC-CMs. The platform combines the optical recording of a small molecule fluorescent voltage sensing probe (VoltageFluor2.1.Cl), an automated high throughput microscope and automated image analysis to rapidly generate physiological measurements of cardiomyocytes (CMs). The technique can be readily adapted on any high content imager to study hiPSC-CM physiology and predict the proarrhythmic effects of drug candidates.
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Affiliation(s)
- Wesley L McKeithan
- Department of Medicine, Cardiovascular Institute, Stanford University, Stanford, CA, United States.,Graduate School of Biomedical Sciences, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, United States
| | - Alex Savchenko
- Department of Medicine, Cardiovascular Institute, Stanford University, Stanford, CA, United States
| | - Michael S Yu
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, United States.,Department of Bioengineering, University of California, San Diego, San Diego, CA, United States
| | | | - Arne A N Bruyneel
- Department of Medicine, Cardiovascular Institute, Stanford University, Stanford, CA, United States
| | | | - Alexandre R Colas
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, United States
| | - Evan W Miller
- Departments of Chemistry, Molecular and Cell Biology, Helen Wills Neuroscience, University of California, Berkeley, Berkeley, CA, United States
| | - John R Cashman
- Human BioMolecular Research Institute, San Diego, CA, United States
| | - Mark Mercola
- Department of Medicine, Cardiovascular Institute, Stanford University, Stanford, CA, United States
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Jeevaratnam K, Chadda KR, Huang CLH, Camm AJ. Cardiac Potassium Channels: Physiological Insights for Targeted Therapy. J Cardiovasc Pharmacol Ther 2017; 23:119-129. [PMID: 28946759 PMCID: PMC5808825 DOI: 10.1177/1074248417729880] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The development of novel drugs specifically directed at the ion channels underlying particular features of cardiac action potential (AP) initiation, recovery, and refractoriness would contribute to an optimized approach to antiarrhythmic therapy that minimizes potential cardiac and extracardiac toxicity. Of these, K+ channels contribute numerous and diverse currents with specific actions on different phases in the time course of AP repolarization. These features and their site-specific distribution make particular K+ channel types attractive therapeutic targets for the development of pharmacological agents attempting antiarrhythmic therapy in conditions such as atrial fibrillation. However, progress in the development of such temporally and spatially selective antiarrhythmic drugs against particular ion channels has been relatively limited, particularly in view of our incomplete understanding of the complex physiological roles and interactions of the various ionic currents. This review summarizes the physiological properties of the main cardiac potassium channels and the way in which they modulate cardiac electrical activity and then critiques a number of available potential antiarrhythmic drugs directed at them.
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Affiliation(s)
- Kamalan Jeevaratnam
- 1 Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.,2 School of Medicine, Perdana University-Royal College of Surgeons Ireland, Serdang, Selangor Darul Ehsan, Malaysia
| | - Karan R Chadda
- 1 Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.,3 Physiological Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Christopher L-H Huang
- 3 Physiological Laboratory, University of Cambridge, Cambridge, United Kingdom.,4 Division of Cardiovascular Biology, Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - A John Camm
- 5 Cardiac Clinical Academic Group, St George's Hospital Medical School, University of London, Cranmer Terrace, London, United Kingdom
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50
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Juhász V, Hornyik T, Benák A, Nagy N, Husti Z, Pap R, Sághy L, Virág L, Varró A, Baczkó I. Comparison of the effects of I K,ACh, I Kr, and I Na block in conscious dogs with atrial fibrillation and on action potentials in remodeled atrial trabeculae. Can J Physiol Pharmacol 2017; 96:18-25. [PMID: 28892643 DOI: 10.1139/cjpp-2017-0342] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and a major cause of morbidity and mortality. Traditional antiarrhythmic agents used for restoration of sinus rhythm have limited efficacy in long-term AF and they may possess ventricular proarrhythmic adverse effects, especially in patients with structural heart disease. The acetylcholine receptor-activated potassium channel (IK,ACh) represents an atrial selective target for future AF management. We investigated the effects of the IK,ACh blocker tertiapin-Q (TQ), a derivative of the honeybee toxin tertiapin, on chronic atrial tachypacing-induced AF in conscious dogs, without the influence of anesthetics that modulate a number of cardiac ion channels. Action potentials (APs) were recorded from right atrial trabeculae isolated from dogs with AF. TQ significantly and dose-dependently reduced AF incidence and AF episode duration, prolonged atrial effective refractory period, and prolonged AP duration. The reference drugs propafenone and dofetilide, both used in the clinical management of AF, exerted similar effects against AF in vivo. Dofetilide prolonged atrial AP duration, whereas propafenone increased atrial conduction time. TQ and propafenone did not affect the QT interval, whereas dofetilide prolonged the QT interval. Our results show that inhibition of IK,ACh may represent a novel, atrial-specific target for the management of AF in chronic AF.
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Affiliation(s)
- Viktor Juhász
- a Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - Tibor Hornyik
- a Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - Attila Benák
- b 2nd Department of Internal Medicine and Cardiology Centre, University of Szeged, Szeged, Hungary
| | - Norbert Nagy
- c MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary
| | - Zoltán Husti
- a Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - Róbert Pap
- b 2nd Department of Internal Medicine and Cardiology Centre, University of Szeged, Szeged, Hungary
| | - László Sághy
- b 2nd Department of Internal Medicine and Cardiology Centre, University of Szeged, Szeged, Hungary
| | - László Virág
- a Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - András Varró
- a Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary.,c MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary
| | - István Baczkó
- a Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
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