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Filatova TS, Dzhumaniiazova I, Abramochkin DV. The metamorphosis of amphibian myocardium: moving to the heart of the matter. J Exp Biol 2024; 227:jeb247712. [PMID: 38916053 DOI: 10.1242/jeb.247712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 04/26/2024] [Indexed: 06/26/2024]
Abstract
Amphibians are a classical object for physiological studies, and they are of great value for developmental studies owing to their transition from an aquatic larval form to an adult form with a terrestrial lifestyle. Axolotls (Ambystoma mexicanum) are of special interest for such studies because of their neoteny and facultative pedomorphosis, as in these animals, metamorphosis can be induced and fully controlled in laboratory conditions. It has been suggested that their metamorphosis, associated with gross anatomical changes in the heart, also involves physiological and electrical remodeling of the myocardium. We used whole-cell patch clamp to investigate possible changes caused by metamorphosis in electrical activity and major ionic currents in cardiomyocytes isolated from paedomorphic and metamorphic axolotls. T4-induced metamorphosis caused shortening of atrial and ventricular action potentials (APs), with no changes in resting membrane potential or maximum velocity of AP upstroke, favoring higher heart rate possible in metamorphic animals. Potential-dependent potassium currents in axolotl myocardium were represented by delayed rectifier currents IKr and IKs, and upregulation of IKs caused by metamorphosis probably underlies AP shortening. Metamorphosis was associated with downregulation of inward rectifier current IK1, probably serving to increase the excitability of myocardium in metamorphic animals. Metamorphosis also led to a slight increase in fast sodium current INa with no changes in its steady-state kinetics and to a significant upregulation of ICa in both atrial and ventricular cells, indicating stronger Ca2+ influx for higher cardiac contractility in metamorphic salamanders. Taken together, these changes serve to increase cardiac reserve in metamorphic animals.
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Affiliation(s)
- Tatiana S Filatova
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye gory, 1, 12, Moscow 119234, Russia
| | - Irina Dzhumaniiazova
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye gory, 1, 12, Moscow 119234, Russia
| | - Denis V Abramochkin
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye gory, 1, 12, Moscow 119234, Russia
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Chen S, Wu S, Lin B. The potential therapeutic value of the natural plant compounds matrine and oxymatrine in cardiovascular diseases. Front Cardiovasc Med 2024; 11:1417672. [PMID: 39041001 PMCID: PMC11260750 DOI: 10.3389/fcvm.2024.1417672] [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: 04/15/2024] [Accepted: 06/17/2024] [Indexed: 07/24/2024] Open
Abstract
Matrine (MT) and Oxymatrine (OMT) are two natural alkaloids derived from plants. These bioactive compounds are notable for their diverse pharmacological effects and have been extensively studied and recognized in the treatment of cardiovascular diseases in recent years. The cardioprotective effects of MT and OMT involve multiple aspects, primarily including antioxidative stress, anti-inflammatory actions, anti-atherosclerosis, restoration of vascular function, and inhibition of cardiac remodeling and failure. Clinical pharmacology research has identified numerous novel molecular mechanisms of OMT and MT, such as JAK/STAT, Nrf2/HO-1, PI3 K/AKT, TGF-β1/Smad, and Notch pathways, providing new evidence supporting their promising therapeutic potential against cardiovascular diseases. Thus, this review aims to investigate the potential applications of MT and OMT in treating cardiovascular diseases, encompassing their mechanisms, efficacy, and safety, confirming their promise as lead compounds in anti-cardiovascular disease drug development.
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Affiliation(s)
| | | | - Bin Lin
- Department of Cardiovascular Medicine, Wenzhou Central Hospital, Wenzhou, China
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Nasilli G, Verkerk AO, O’Reilly M, Yiangou L, Davis RP, Casini S, Remme CA. Chronic Mexiletine Administration Increases Sodium Current in Non-Diseased Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes. Biomedicines 2024; 12:1212. [PMID: 38927420 PMCID: PMC11200762 DOI: 10.3390/biomedicines12061212] [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: 05/15/2024] [Accepted: 05/21/2024] [Indexed: 06/28/2024] Open
Abstract
A sodium current (INa) reduction occurs in the setting of many acquired and inherited conditions and is associated with cardiac conduction slowing and increased arrhythmia risks. The sodium channel blocker mexiletine has been shown to restore the trafficking of mutant sodium channels to the membrane. However, these studies were mostly performed in heterologous expression systems using high mexiletine concentrations. Moreover, the chronic effects on INa in a non-diseased cardiomyocyte environment remain unknown. In this paper, we investigated the chronic and acute effects of a therapeutic dose of mexiletine on INa and the action potential (AP) characteristics in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) of a healthy individual. Control hiPSC-CMs were incubated for 48 h with 10 µM mexiletine or vehicle. Following the wash-out of mexiletine, patch clamp analysis and immunocytochemistry experiments were performed. The incubation of hiPSC-CMs for 48 h with mexiletine (followed by wash-out) induced a significant increase in peak INa of ~75%, without any significant change in the voltage dependence of (in)activation. This was accompanied by a significant increase in AP upstroke velocity, without changes in other AP parameters. The immunocytochemistry experiments showed a significant increase in membrane Nav1.5 fluorescence following a 48 h incubation with mexiletine. The acute re-exposure of hiPSC-CMs to 10 µM mexiletine resulted in a small but significant increase in AP duration, without changes in AP upstroke velocity, peak INa density, or the INa voltage dependence of (in)activation. Importantly, the increase in the peak INa density and resulting AP upstroke velocity induced by chronic mexiletine incubation was not counteracted by the acute re-administration of the drug. In conclusion, the chronic administration of a clinically relevant concentration of mexiletine increases INa density in non-diseased hiPSC-CMs, likely by enhancing the membrane trafficking of sodium channels. Our findings identify mexiletine as a potential therapeutic strategy to enhance and/or restore INa and cardiac conduction.
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Affiliation(s)
- Giovanna Nasilli
- Department of Experimental Cardiology, Amsterdam University Medical Center, University of Amsterdam, Heart Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands (A.O.V.)
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, 1105 AZ Amsterdam, The Netherlands
| | - Arie O. Verkerk
- Department of Experimental Cardiology, Amsterdam University Medical Center, University of Amsterdam, Heart Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands (A.O.V.)
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, 1105 AZ Amsterdam, The Netherlands
- Department of Medical Biology, Amsterdam University Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Molly O’Reilly
- Department of Experimental Cardiology, Amsterdam University Medical Center, University of Amsterdam, Heart Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands (A.O.V.)
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, 1105 AZ Amsterdam, The Netherlands
| | - Loukia Yiangou
- Department of Anatomy and Embryology, Leiden University Medical Center, Albinusdreef 2, 2300 RC Leiden, The Netherlands
| | - Richard P. Davis
- Department of Anatomy and Embryology, Leiden University Medical Center, Albinusdreef 2, 2300 RC Leiden, The Netherlands
- The Novo Nordisk Foundation Center for Stem Cell Medicine (reNEW), Leiden University Medical Center, Albinusdreef 2, 2300 RC Leiden, The Netherlands
| | - Simona Casini
- Department of Experimental Cardiology, Amsterdam University Medical Center, University of Amsterdam, Heart Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands (A.O.V.)
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, 1105 AZ Amsterdam, The Netherlands
| | - Carol Ann Remme
- Department of Experimental Cardiology, Amsterdam University Medical Center, University of Amsterdam, Heart Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands (A.O.V.)
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, 1105 AZ Amsterdam, The Netherlands
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4
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Gutiérrez LK, Moreno-Manuel AI, Jalife J. Kir2.1-Na V1.5 channelosome and its role in arrhythmias in inheritable cardiac diseases. Heart Rhythm 2024; 21:630-646. [PMID: 38244712 DOI: 10.1016/j.hrthm.2024.01.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 01/10/2024] [Accepted: 01/13/2024] [Indexed: 01/22/2024]
Abstract
Sudden cardiac death in children and young adults is a relatively rare but tragic event whose pathophysiology is unknown at the molecular level. Evidence indicates that the main cardiac sodium channel (NaV1.5) and the strong inward rectifier potassium channel (Kir2.1) physically interact and form macromolecular complexes (channelosomes) with common partners, including adapter, scaffolding, and regulatory proteins that help them traffic together to their eventual membrane microdomains. Most important, dysfunction of either or both ion channels has direct links to hereditary human diseases. For example, certain mutations in the KCNJ2 gene encoding the Kir2.1 protein result in Andersen-Tawil syndrome type 1 and alter both inward rectifier potassium and sodium inward currents. Similarly, trafficking-deficient mutations in the gene encoding the NaV1.5 protein (SCN5A) result in Brugada syndrome and may also disturb both inward rectifier potassium and sodium inward currents. Moreover, gain-of-function mutations in KCNJ2 result in short QT syndrome type 3, which is extremely rare but highly arrhythmogenic, and can modify Kir2.1-NaV1.5 interactions in a mutation-specific way, further highlighting the relevance of channelosomes in ion channel diseases. By expressing mutant proteins that interrupt or modify Kir2.1 or NaV1.5 function in animal models and patient-specific pluripotent stem cell-derived cardiomyocytes, investigators are defining for the first time the mechanistic framework of how mutation-induced dysregulation of the Kir2.1-NaV1.5 channelosome affects cardiac excitability, resulting in arrhythmias and sudden death in different cardiac diseases.
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Affiliation(s)
- Lilian K Gutiérrez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | | | - José Jalife
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain; CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain; Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan.
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5
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Li E, van der Heyden MAG. The network of cardiac K IR2.1: its function, cellular regulation, electrical signaling, diseases and new drug avenues. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2024:10.1007/s00210-024-03116-5. [PMID: 38683369 DOI: 10.1007/s00210-024-03116-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 04/19/2024] [Indexed: 05/01/2024]
Abstract
The functioning of the human heart relies on complex electrical and communication systems that coordinate cardiac contractions and sustain rhythmicity. One of the key players contributing to this intricate system is the KIR2.1 potassium ion channel, which is encoded by the KCNJ2 gene. KIR2.1 channels exhibit abundant expression in both ventricular myocytes and Purkinje fibers, exerting an important role in maintaining the balance of intracellular potassium ion levels within the heart. And by stabilizing the resting membrane potential and contributing to action potential repolarization, these channels have an important role in cardiac excitability also. Either gain- or loss-of-function mutations, but also acquired impairments of their function, are implicated in the pathogenesis of diverse types of cardiac arrhythmias. In this review, we aim to elucidate the system functions of KIR2.1 channels related to cellular electrical signaling, communication, and their contributions to cardiovascular disease. Based on this knowledge, we will discuss existing and new pharmacological avenues to modulate their function.
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Affiliation(s)
- Encan Li
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, Netherlands
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, Netherlands.
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Cruz FM, Macías Á, Moreno-Manuel AI, Gutiérrez LK, Vera-Pedrosa ML, Martínez-Carrascoso I, Pérez PS, Robles JMR, Bermúdez-Jiménez FJ, Díaz-Agustín A, de Benito FM, Arias-Santiago S, Braza-Boils A, Martín-Martínez M, Gutierrez-Rodríguez M, Bernal JA, Zorio E, Jiménez-Jaimez J, Jalife J. Extracellular Kir2.1 C122Y Mutant Upsets Kir2.1-PIP 2 Bonds and Is Arrhythmogenic in Andersen-Tawil Syndrome. Circ Res 2024; 134:e52-e71. [PMID: 38497220 PMCID: PMC11009053 DOI: 10.1161/circresaha.123.323895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 02/29/2024] [Indexed: 03/19/2024]
Abstract
BACKGROUND Andersen-Tawil syndrome type 1 is a rare heritable disease caused by mutations in the gene coding the strong inwardly rectifying K+ channel Kir2.1. The extracellular Cys (cysteine)122-to-Cys154 disulfide bond in the channel structure is crucial for proper folding but has not been associated with correct channel function at the membrane. We evaluated whether a human mutation at the Cys122-to-Cys154 disulfide bridge leads to Kir2.1 channel dysfunction and arrhythmias by reorganizing the overall Kir2.1 channel structure and destabilizing its open state. METHODS We identified a Kir2.1 loss-of-function mutation (c.366 A>T; p.Cys122Tyr) in an ATS1 family. To investigate its pathophysiological implications, we generated an AAV9-mediated cardiac-specific mouse model expressing the Kir2.1C122Y variant. We employed a multidisciplinary approach, integrating patch clamping and intracardiac stimulation, molecular biology techniques, molecular dynamics, and bioluminescence resonance energy transfer experiments. RESULTS Kir2.1C122Y mice recapitulated the ECG features of ATS1 independently of sex, including corrected QT prolongation, conduction defects, and increased arrhythmia susceptibility. Isolated Kir2.1C122Y cardiomyocytes showed significantly reduced inwardly rectifier K+ (IK1) and inward Na+ (INa) current densities independently of normal trafficking. Molecular dynamics predicted that the C122Y mutation provoked a conformational change over the 2000-ns simulation, characterized by a greater loss of hydrogen bonds between Kir2.1 and phosphatidylinositol 4,5-bisphosphate than wild type (WT). Therefore, the phosphatidylinositol 4,5-bisphosphate-binding pocket was destabilized, resulting in a lower conductance state compared with WT. Accordingly, on inside-out patch clamping, the C122Y mutation significantly blunted Kir2.1 sensitivity to increasing phosphatidylinositol 4,5-bisphosphate concentrations. In addition, the Kir2.1C122Y mutation resulted in channelosome degradation, demonstrating temporal instability of both Kir2.1 and NaV1.5 proteins. CONCLUSIONS The extracellular Cys122-to-Cys154 disulfide bond in the tridimensional Kir2.1 channel structure is essential for the channel function. We demonstrate that breaking disulfide bonds in the extracellular domain disrupts phosphatidylinositol 4,5-bisphosphate-dependent regulation, leading to channel dysfunction and defects in Kir2.1 energetic stability. The mutation also alters functional expression of the NaV1.5 channel and ultimately leads to conduction disturbances and life-threatening arrhythmia characteristic of Andersen-Tawil syndrome type 1.
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Affiliation(s)
- Francisco M. Cruz
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | - Álvaro Macías
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | | | - Lilian K. Gutiérrez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | | | | | | | | | - Francisco J Bermúdez-Jiménez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
- Servicio de Cardiología, Hospital Universitario Virgen de las Nieves, Granada, Spain
- Instituto de Investigación Biosanitaria de Granada IBS, Granada, Spain
| | - Aitor Díaz-Agustín
- Instituto de Química Médica (IQM), Consejo Superior de Investigaciones Científicas (CSIC), 28006 Madrid, Spain
| | - Fernando Martínez de Benito
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Salvador Arias-Santiago
- Servicio de Dermatología Hospital Universitario Virgen de las Nieves
- Instituto de Investigación Biosanitaria de Granada IBS, Granada, Spain
| | - Aitana Braza-Boils
- Unit of Inherited Cardiomyopathies and Sudden Death (CAFAMUSME), Health Research Institute La Fe, La Fe Hospital, Valencia, Spain
- Cardiology Department, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Mercedes Martín-Martínez
- Instituto de Química Médica (IQM), Consejo Superior de Investigaciones Científicas (CSIC), 28006 Madrid, Spain
| | - Marta Gutierrez-Rodríguez
- Instituto de Química Médica (IQM), Consejo Superior de Investigaciones Científicas (CSIC), 28006 Madrid, Spain
| | - Juan A. Bernal
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Esther Zorio
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
- Unit of Inherited Cardiomyopathies and Sudden Death (CAFAMUSME), Health Research Institute La Fe, La Fe Hospital, Valencia, Spain
- Cardiology Department, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Juan Jiménez-Jaimez
- Servicio de Cardiología, Hospital Universitario Virgen de las Nieves, Granada, Spain
- Instituto de Investigación Biosanitaria de Granada IBS, Granada, Spain
| | - José Jalife
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
- Departments of Medicine and Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
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Morrissette-McAlmon J, Xu WR, Teuben R, Boheler KR, Tung L. Adipocyte-mediated electrophysiological remodeling of human stem cell - derived cardiomyocytes. J Mol Cell Cardiol 2024; 189:52-65. [PMID: 38346641 DOI: 10.1016/j.yjmcc.2024.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 01/20/2024] [Accepted: 02/06/2024] [Indexed: 03/02/2024]
Abstract
Adipocytes normally accumulate in the epicardial and pericardial layers around the human heart, but their infiltration into the myocardium can be proarrhythmic. METHODS AND RESULTS: Human adipose derived stem/stromal cells and human induced pluripotent stem cells (hiPSC) were differentiated, respectively into predominantly white fat-like adipocytes (hAdip) and ventricular cardiomyocytes (CMs). Adipocytes cultured in CM maintenance medium (CM medium) maintained their morphology, continued to express adipogenic markers, and retained clusters of intracellular lipid droplets. In contrast, hiPSC-CMs cultivated in adipogenic growth medium displayed abnormal cell morphologies and more clustering across the monolayer. Pre-plated hiPSC-CMs co-cultured in direct contact with hAdips in CM medium displayed prolonged action potential durations, increased triangulation, slowed conduction velocity, increased conduction velocity heterogeneity, and prolonged calcium transients. When hAdip-conditioned medium was added to monolayer cultures of hiPSC-CMs, results similar to those recorded with direct co-cultures were observed. Both co-culture and conditioned medium experiments resulted in increases in transcript abundance of SCN10A, CACNA1C, SLC8A1, and RYR2, with a decrease in KCNJ2. Human adipokine immunoblots revealed the presence of cytokines that were elevated in adipocyte-conditioned medium, including MCP-1, IL-6, IL-8 and CFD that could induce electrophysiological changes in cultured hiPSC-CMs. CONCLUSIONS: Co-culture of hiPSC-CMs with hAdips reveals a potentially pathogenic role of infiltrating human adipocytes on myocardial tissue. In the absence of structural changes, hAdip paracrine release alone is sufficient to cause CM electrophysiological dysfunction mirroring the co-culture conditions. These effects, mediated largely by paracrine mechanisms, could promote arrhythmias in the heart.
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Affiliation(s)
| | - William R Xu
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Roald Teuben
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kenneth R Boheler
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Leslie Tung
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Cheng F, Dennis AB, Baumann O, Kirschbaum F, Abdelilah-Seyfried S, Tiedemann R. Gene and Allele-Specific Expression Underlying the Electric Signal Divergence in African Weakly Electric Fish. Mol Biol Evol 2024; 41:msae021. [PMID: 38410843 PMCID: PMC10897887 DOI: 10.1093/molbev/msae021] [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: 10/31/2023] [Revised: 12/15/2023] [Accepted: 01/29/2024] [Indexed: 02/28/2024] Open
Abstract
In the African weakly electric fish genus Campylomormyrus, electric organ discharge signals are strikingly different in shape and duration among closely related species, contribute to prezygotic isolation, and may have triggered an adaptive radiation. We performed mRNA sequencing on electric organs and skeletal muscles (from which the electric organs derive) from 3 species with short (0.4 ms), medium (5 ms), and long (40 ms) electric organ discharges and 2 different cross-species hybrids. We identified 1,444 upregulated genes in electric organ shared by all 5 species/hybrid cohorts, rendering them candidate genes for electric organ-specific properties in Campylomormyrus. We further identified several candidate genes, including KCNJ2 and KLF5, and their upregulation may contribute to increased electric organ discharge duration. Hybrids between a short (Campylomormyrus compressirostris) and a long (Campylomormyrus rhynchophorus) discharging species exhibit electric organ discharges of intermediate duration and showed imbalanced expression of KCNJ2 alleles, pointing toward a cis-regulatory difference at this locus, relative to electric organ discharge duration. KLF5 is a transcription factor potentially balancing potassium channel gene expression, a crucial process for the formation of an electric organ discharge. Unraveling the genetic basis of the species-specific modulation of the electric organ discharge in Campylomormyrus is crucial for understanding the adaptive radiation of this emerging model taxon of ecological (perhaps even sympatric) speciation.
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Affiliation(s)
- Feng Cheng
- Unit of Evolutionary Biology/Systematic Zoology, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
| | - Alice B Dennis
- Unit of Evolutionary Biology/Systematic Zoology, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
- Laboratory of Adaptive Evolution and Genomics, Research Unit of Environmental and Evolutionary Biology, Institute of Life, Earth & Environment, University of Namur, Namur, Belgium
| | - Otto Baumann
- Department of Animal Physiology, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
| | - Frank Kirschbaum
- Unit of Evolutionary Biology/Systematic Zoology, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
- Department of Crop and Animal Science, Faculty of Life Sciences, Humboldt University, Berlin, Germany
| | - Salim Abdelilah-Seyfried
- Department of Animal Physiology, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
| | - Ralph Tiedemann
- Unit of Evolutionary Biology/Systematic Zoology, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
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9
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Zhang S, Jia Y, Ma G, Yang Y, Cao Z, Luo A, Zhang Z, Li S, Wen J, Liu H, Ma J. Bupleurum exerts antiarrhythmic effects by inhibiting L-type calcium channels in mouse ventricular myocytes. Biochem Biophys Res Commun 2024; 691:149322. [PMID: 38039833 DOI: 10.1016/j.bbrc.2023.149322] [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: 09/07/2023] [Revised: 11/16/2023] [Accepted: 11/22/2023] [Indexed: 12/03/2023]
Abstract
BACKGROUND Bupleurum (Bup), is a traditional effective medicine to treat colds and fevers in clinics. Multiple studies have demonstrated that Bup exhibites various biological activities, including cardioprotective effects, anti-inflammatory, anticancer, antipyretic, antimicrobial, and antiviral effects, etc. Currently, the effects of Bup on cardiac electrophysiology have not been reported yet. METHODS Electrocardiogram recordings were used to investigate the effects of Bup on aconitine-induced arrhythmias. Patch-clamp techniques were used to explore the effects of Bup on APs and ion currents. RESULTS Bup reduced the incidence of ventricular fibrillation (VF) and delayed the onset time of ventricular tachycardia (VT) in mice. Additionally, Bup (40 mg/mL) suppressed DADs induced by high-Ca2+ and shortened action potential duration at 50 % completion of repolarization (APD50) and action potential duration at 90 % completion of repolarization (APD90) to 60.89 % ± 8.40 % and 68.94 % ± 3.24 % of the control, respectively. Moreover, Bup inhibited L-type calcium currents (ICa.L) in a dose-dependent manner, with an IC50 value of 25.36 mg/mL. Furthermore, Bup affected the gated kinetics of L-type calcium channels by slowing down steady-state activation, accelerating the steady-state inactivation, and delaying the inactivation-recovery process. However, Bup had no effects on the Transient sodium current (INa.T), ATX II-increased late sodium current (INa.L), transient outward current (Ito), delayed rectifier potassium current (IK), or inward rectifier potassium current (IK1). CONCLUSION Bup is an antiarrhythmic agent that may exert its antiarrhythmic effects by inhibiting L-type calcium channels.
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Affiliation(s)
- Shuanglin Zhang
- Institute of Cardiovascular Diseases, Hubei Province Key Laboratory of Occupational Hazard Identification and Control, School of Medicine, Wuhan University of Science and Technology, Wuhan, 430065, China
| | - Yuzhong Jia
- Institute of Cardiovascular Diseases, Hubei Province Key Laboratory of Occupational Hazard Identification and Control, School of Medicine, Wuhan University of Science and Technology, Wuhan, 430065, China
| | - Guolan Ma
- Institute of Cardiovascular Diseases, Hubei Province Key Laboratory of Occupational Hazard Identification and Control, School of Medicine, Wuhan University of Science and Technology, Wuhan, 430065, China
| | - Yanyan Yang
- Institute of Biology and Medicine, College of Life and Health Sciences, Wuhan University of Science and Technology, Wuhan, 430065, China
| | - Zhenzhen Cao
- Institute of Cardiovascular Diseases, Hubei Province Key Laboratory of Occupational Hazard Identification and Control, School of Medicine, Wuhan University of Science and Technology, Wuhan, 430065, China.
| | - Antao Luo
- Institute of Cardiovascular Diseases, Hubei Province Key Laboratory of Occupational Hazard Identification and Control, School of Medicine, Wuhan University of Science and Technology, Wuhan, 430065, China.
| | - Zefu Zhang
- Institute of Cardiovascular Diseases, Hubei Province Key Laboratory of Occupational Hazard Identification and Control, School of Medicine, Wuhan University of Science and Technology, Wuhan, 430065, China
| | - Shihan Li
- Institute of Cardiovascular Diseases, Hubei Province Key Laboratory of Occupational Hazard Identification and Control, School of Medicine, Wuhan University of Science and Technology, Wuhan, 430065, China
| | - Jie Wen
- Institute of Cardiovascular Diseases, Hubei Province Key Laboratory of Occupational Hazard Identification and Control, School of Medicine, Wuhan University of Science and Technology, Wuhan, 430065, China
| | - Hanfeng Liu
- Institute of Biology and Medicine, College of Life and Health Sciences, Wuhan University of Science and Technology, Wuhan, 430065, China
| | - Jihua Ma
- Institute of Cardiovascular Diseases, Hubei Province Key Laboratory of Occupational Hazard Identification and Control, School of Medicine, Wuhan University of Science and Technology, Wuhan, 430065, China; Institute of Biology and Medicine, College of Life and Health Sciences, Wuhan University of Science and Technology, Wuhan, 430065, China
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10
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Han JL, Heinson YW, Chua CJ, Liu W, Entcheva E. CRISPRi gene modulation and all-optical electrophysiology in post-differentiated human iPSC-cardiomyocytes. Commun Biol 2023; 6:1236. [PMID: 38062109 PMCID: PMC10703822 DOI: 10.1038/s42003-023-05627-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 11/22/2023] [Indexed: 12/18/2023] Open
Abstract
Uncovering gene-phenotype relationships can be enabled by precise gene modulation in human induced pluripotent stem-cell-derived cardiomyocytes (iPSC-CMs) and follow up phenotyping using scalable all-optical electrophysiology platforms. Such efforts towards human functional genomics can be aided by recent CRISPR-derived technologies for reversible gene inhibition or activation (CRISPRi/a). We set out to characterize the performance of CRISPRi in post-differentiated iPSC-CMs, targeting key cardiac ion channel genes, KCNH2, KCNJ2, and GJA1, and providing a multiparametric quantification of the effects on cardiac repolarization, stability of the resting membrane potential and conduction properties using all-optical tools. More potent CRISPRi effectors, e.g., Zim3, and optimized viral delivery led to improved performance on par with the use of CRISPRi iPSC lines. Confirmed mild yet specific phenotype changes when CRISPRi is deployed in non-dividing differentiated heart cells is an important step towards more holistic pre-clinical cardiotoxicity testing and for future therapeutic use in vivo.
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Affiliation(s)
- Julie L Han
- Department of Biomedical Engineering, The George Washington University, Washington, DC, 20052, USA
| | - Yuli W Heinson
- Department of Biomedical Engineering, The George Washington University, Washington, DC, 20052, USA
| | - Christianne J Chua
- Department of Biomedical Engineering, The George Washington University, Washington, DC, 20052, USA
| | - Wei Liu
- Department of Biomedical Engineering, The George Washington University, Washington, DC, 20052, USA
| | - Emilia Entcheva
- Department of Biomedical Engineering, The George Washington University, Washington, DC, 20052, USA.
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11
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Ramos-Mondragón R, Lozhkin A, Vendrov AE, Runge MS, Isom LL, Madamanchi NR. NADPH Oxidases and Oxidative Stress in the Pathogenesis of Atrial Fibrillation. Antioxidants (Basel) 2023; 12:1833. [PMID: 37891912 PMCID: PMC10604902 DOI: 10.3390/antiox12101833] [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: 08/18/2023] [Revised: 09/26/2023] [Accepted: 09/29/2023] [Indexed: 10/29/2023] Open
Abstract
Atrial fibrillation (AF) is the most common type of cardiac arrhythmia and its prevalence increases with age. The irregular and rapid contraction of the atria can lead to ineffective blood pumping, local blood stasis, blood clots, ischemic stroke, and heart failure. NADPH oxidases (NOX) and mitochondria are the main sources of reactive oxygen species in the heart, and dysregulated activation of NOX and mitochondrial dysfunction are associated with AF pathogenesis. NOX- and mitochondria-derived oxidative stress contribute to the onset of paroxysmal AF by inducing electrophysiological changes in atrial myocytes and structural remodeling in the atria. Because high atrial activity causes cardiac myocytes to expend extremely high energy to maintain excitation-contraction coupling during persistent AF, mitochondria, the primary energy source, undergo metabolic stress, affecting their morphology, Ca2+ handling, and ATP generation. In this review, we discuss the role of oxidative stress in activating AF-triggered activities, regulating intracellular Ca2+ handling, and functional and anatomical reentry mechanisms, all of which are associated with AF initiation, perpetuation, and progression. Changes in the extracellular matrix, inflammation, ion channel expression and function, myofibril structure, and mitochondrial function occur during the early transitional stages of AF, opening a window of opportunity to target NOX and mitochondria-derived oxidative stress using isoform-specific NOX inhibitors and mitochondrial ROS scavengers, as well as drugs that improve mitochondrial dynamics and metabolism to treat persistent AF and its transition to permanent AF.
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Affiliation(s)
- Roberto Ramos-Mondragón
- Department of Pharmacology, University of Michigan, 1150 West Medical Center Drive, 2301 Medical Science Research Building III, Ann Arbor, MI 48109, USA; (R.R.-M.); (L.L.I.)
| | - Andrey Lozhkin
- Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI 48019, USA; (A.L.); (A.E.V.); (M.S.R.)
| | - Aleksandr E. Vendrov
- Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI 48019, USA; (A.L.); (A.E.V.); (M.S.R.)
| | - Marschall S. Runge
- Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI 48019, USA; (A.L.); (A.E.V.); (M.S.R.)
| | - Lori L. Isom
- Department of Pharmacology, University of Michigan, 1150 West Medical Center Drive, 2301 Medical Science Research Building III, Ann Arbor, MI 48109, USA; (R.R.-M.); (L.L.I.)
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Nageswara R. Madamanchi
- Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI 48019, USA; (A.L.); (A.E.V.); (M.S.R.)
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12
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Weinberg SH. Sodium channel subpopulations with distinct biophysical properties and subcellular localization enhance cardiac conduction. J Gen Physiol 2023; 155:e202313382. [PMID: 37285024 PMCID: PMC10250552 DOI: 10.1085/jgp.202313382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 05/02/2023] [Accepted: 05/24/2023] [Indexed: 06/08/2023] Open
Abstract
Sodium (Na+) current is responsible for the rapid depolarization of cardiac myocytes that triggers the cardiac action potential upstroke. Recent studies have illustrated the presence of multiple pools of Na+ channels with distinct biophysical properties and subcellular localization, including clustering of channels at the intercalated disk and along the lateral membrane. Computational studies predict that Na+ channel clusters at the intercalated disk can regulate cardiac conduction via modulation of the narrow intercellular cleft between electrically coupled myocytes. However, these studies have primarily focused on the redistribution of Na+ channels between intercalated disk and lateral membranes and have not considered the distinct biophysical properties of the Na+ channel subpopulations. In this study, we use computational modeling to simulate computational models of single cardiac cells and one-dimensional cardiac tissues and predict the function of distinct Na+ channel subpopulations. Single-cell simulations predict that a subpopulation of Na+ channels with shifted steady-state activation and inactivation voltage dependency promotes an earlier action potential upstroke. In cardiac tissues that account for distinct subcellular spatial localization, simulations predict that shifted Na+ channels contribute to faster and more robust conduction in response to changes in tissue structure (i.e., cleft width), gap junctional coupling, and rapid pacing rates. Simulations predict that the intercalated disk-localized shifted Na+ channels contribute proportionally more to total Na+ charge than lateral membrane-localized Na+ channels. Importantly, our work supports the hypothesis that Na+ channel redistribution may be a critical mechanism by which cells can respond to perturbations to support fast and robust conduction.
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Affiliation(s)
- Seth H. Weinberg
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
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13
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Meyer KM, Malhotra N, Kwak JS, El Refaey M. Relevance of KCNJ5 in Pathologies of Heart Disease. Int J Mol Sci 2023; 24:10849. [PMID: 37446026 PMCID: PMC10341679 DOI: 10.3390/ijms241310849] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 06/16/2023] [Accepted: 06/21/2023] [Indexed: 07/15/2023] Open
Abstract
Abnormalities in G-protein-gated inwardly rectifying potassium (GIRK) channels have been implicated in diseased states of the cardiovascular system; however, the role of GIRK4 (Kir3.4) in cardiac physiology and pathophysiology has yet to be completely understood. Within the heart, the KACh channel, consisting of two GIRK1 and two GIRK4 subunits, plays a major role in modulating the parasympathetic nervous system's influence on cardiac physiology. Being that GIRK4 is necessary for the functional KACh channel, KCNJ5, which encodes GIRK4, it presents as a therapeutic target for cardiovascular pathology. Human variants in KCNJ5 have been identified in familial hyperaldosteronism type III, long QT syndrome, atrial fibrillation, and sinus node dysfunction. Here, we explore the relevance of KCNJ5 in each of these diseases. Further, we address the limitations and complexities of discerning the role of KCNJ5 in cardiovascular pathophysiology, as identical human variants of KCNJ5 have been identified in several diseases with overlapping pathophysiology.
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Affiliation(s)
- Karisa M. Meyer
- Department of Surgery, Division of Cardiac Surgery, The Ohio State University, Columbus, OH 43210, USA; (K.M.M.); (N.M.); (J.s.K.)
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Nipun Malhotra
- Department of Surgery, Division of Cardiac Surgery, The Ohio State University, Columbus, OH 43210, USA; (K.M.M.); (N.M.); (J.s.K.)
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Jung seo Kwak
- Department of Surgery, Division of Cardiac Surgery, The Ohio State University, Columbus, OH 43210, USA; (K.M.M.); (N.M.); (J.s.K.)
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Mona El Refaey
- Department of Surgery, Division of Cardiac Surgery, The Ohio State University, Columbus, OH 43210, USA; (K.M.M.); (N.M.); (J.s.K.)
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
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14
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Cruz FM, Macías Á, Moreno-Manuel AI, Gutiérrez LK, Vera-Pedrosa ML, Martínez-Carrascoso I, Pérez PS, Robles JMR, Bermúdez-Jiménez FJ, Díaz-Agustín A, de Benito FM, Santiago SA, Braza-Boils A, Martín-Martínez M, Gutierrez-Rodríguez M, Bernal JA, Zorio E, Jiménez-Jaimez J, Jalife J. Extracellular cysteine disulfide bond break at Cys122 disrupts PIP 2-dependent Kir2.1 channel function and leads to arrhythmias in Andersen-Tawil Syndrome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.07.544151. [PMID: 37333254 PMCID: PMC10274791 DOI: 10.1101/2023.06.07.544151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Background Andersen-Tawil Syndrome Type 1 (ATS1) is a rare heritable disease caused by mutations in the strong inwardly rectifying K+ channel Kir2.1. The extracellular Cys122-to-Cys154 disulfide bond in the Kir2.1 channel structure is crucial for proper folding, but has not been associated with correct channel function at the membrane. We tested whether a human mutation at the Cys122-to-Cys154 disulfide bridge leads to Kir2.1 channel dysfunction and arrhythmias by reorganizing the overall Kir2.1 channel structure and destabilizing the open state of the channel. Methods and Results We identified a Kir2.1 loss-of-function mutation in Cys122 (c.366 A>T; p.Cys122Tyr) in a family with ATS1. To study the consequences of this mutation on Kir2.1 function we generated a cardiac specific mouse model expressing the Kir2.1C122Y mutation. Kir2.1C122Y animals recapitulated the abnormal ECG features of ATS1, like QT prolongation, conduction defects, and increased arrhythmia susceptibility. Kir2.1C122Y mouse cardiomyocytes showed significantly reduced inward rectifier K+ (IK1) and inward Na+ (INa) current densities independently of normal trafficking ability and localization at the sarcolemma and the sarcoplasmic reticulum. Kir2.1C122Y formed heterotetramers with wildtype (WT) subunits. However, molecular dynamic modeling predicted that the Cys122-to-Cys154 disulfide-bond break induced by the C122Y mutation provoked a conformational change over the 2000 ns simulation, characterized by larger loss of the hydrogen bonds between Kir2.1 and phosphatidylinositol-4,5-bisphosphate (PIP2) than WT. Therefore, consistent with the inability of Kir2.1C122Y channels to bind directly to PIP2 in bioluminescence resonance energy transfer experiments, the PIP2 binding pocket was destabilized, resulting in a lower conductance state compared with WT. Accordingly, on inside-out patch-clamping the C122Y mutation significantly blunted Kir2.1 sensitivity to increasing PIP2 concentrations. Conclusion The extracellular Cys122-to-Cys154 disulfide bond in the tridimensional Kir2.1 channel structure is essential to channel function. We demonstrated that ATS1 mutations that break disulfide bonds in the extracellular domain disrupt PIP2-dependent regulation, leading to channel dysfunction and life-threatening arrhythmias.
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Affiliation(s)
- Francisco M. Cruz
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | - Álvaro Macías
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | | | - Lilian K. Gutiérrez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
| | | | | | | | | | - Francisco J Bermúdez-Jiménez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
- Servicio de Cardiología, Hospital Universitario Virgen de las Nieves, Granada, Spain
- Instituto de Investigación Biosanitaria de Granada IBS, Granada, Spain
| | - Aitor Díaz-Agustín
- Instituto de Química Médica (IQM), Consejo Superior de Investigaciones Científicas (CSIC), 28006 Madrid, Spain
| | - Fernando Martínez de Benito
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Salvador Arias Santiago
- Servicio de Dermatología Hospital Universitario Virgen de las Nieves
- Instituto de Investigación Biosanitaria de Granada IBS, Granada, Spain
| | - Aitana Braza-Boils
- Unit of Inherited Cardiomyopathies and Sudden Death (CAFAMUSME), Health Research Institute La Fe, La Fe Hospital, Valencia, Spain
- Cardiology Department, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Mercedes Martín-Martínez
- Instituto de Química Médica (IQM), Consejo Superior de Investigaciones Científicas (CSIC), 28006 Madrid, Spain
| | - Marta Gutierrez-Rodríguez
- Instituto de Química Médica (IQM), Consejo Superior de Investigaciones Científicas (CSIC), 28006 Madrid, Spain
| | - Juan A. Bernal
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Esther Zorio
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
- Unit of Inherited Cardiomyopathies and Sudden Death (CAFAMUSME), Health Research Institute La Fe, La Fe Hospital, Valencia, Spain
- Cardiology Department, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Juan Jiménez-Jaimez
- Servicio de Cardiología, Hospital Universitario Virgen de las Nieves, Granada, Spain
- Instituto de Investigación Biosanitaria de Granada IBS, Granada, Spain
| | - José Jalife
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), 28029 Madrid, Spain
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
- Departments of Medicine and Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
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15
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Han JL, Heinson YW, Chua CJ, Liu W, Entcheva E. CRISPRi Gene Modulation and All-Optical Electrophysiology in Post-Differentiated Human iPSC-Cardiomyocytes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.07.539756. [PMID: 37214814 PMCID: PMC10197536 DOI: 10.1101/2023.05.07.539756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Uncovering gene-phenotype relationships can be enabled by precise gene modulation in human induced pluripotent stem-cell-derived cardiomyocytes (iPSC-CMs) and follow up phenotyping using scalable all-optical electrophysiology platforms. Such efforts towards human functional genomics can be aided by recent CRISPR-derived technologies for reversible gene inhibition or activation (CRISPRi/a). We set out to characterize the performance of CRISPRi in post-differentiated iPSC-CMs, targeting key cardiac ion channel genes, KCNH2, KCNJ2, and GJA1, and providing a multiparametric quantification of the effects on cardiac repolarization, stability of the resting membrane potential and conduction properties using all-optical tools. More potent CRISPRi effectors, e.g. Zim3, and optimized viral delivery led to improved performance on par with the use of CRISPRi iPSC lines. Confirmed mild yet specific phenotype changes when CRISPRi is deployed in non-dividing differentiated heart cells is an important step towards more holistic pre-clinical cardiotoxicity testing and for future therapeutic use in vivo.
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Affiliation(s)
- Julie L. Han
- Department of Biomedical Engineering, The George Washington University, Washington DC 20052, USA
| | - Yuli W. Heinson
- Department of Biomedical Engineering, The George Washington University, Washington DC 20052, USA
| | - Christianne J. Chua
- Department of Biomedical Engineering, The George Washington University, Washington DC 20052, USA
| | - Wei Liu
- Department of Biomedical Engineering, The George Washington University, Washington DC 20052, USA
| | - Emilia Entcheva
- Department of Biomedical Engineering, The George Washington University, Washington DC 20052, USA
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16
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Li E, Kool W, Woolschot L, van der Heyden MAG. Chronic Propafenone Application Increases Functional K IR2.1 Expression In Vitro. Pharmaceuticals (Basel) 2023; 16:ph16030404. [PMID: 36986503 PMCID: PMC10056987 DOI: 10.3390/ph16030404] [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: 02/10/2023] [Revised: 02/28/2023] [Accepted: 03/04/2023] [Indexed: 03/30/2023] Open
Abstract
Expression and activity of inwardly rectifying potassium (KIR) channels within the heart are strictly regulated. KIR channels have an important role in shaping cardiac action potentials, having a limited conductance at depolarized potentials but contributing to the final stage of repolarization and resting membrane stability. Impaired KIR2.1 function causes Andersen-Tawil Syndrome (ATS) and is associated with heart failure. Restoring KIR2.1 function by agonists of KIR2.1 (AgoKirs) would be beneficial. The class 1c antiarrhythmic drug propafenone is identified as an AgoKir; however, its long-term effects on KIR2.1 protein expression, subcellular localization, and function are unknown. Propafenone's long-term effect on KIR2.1 expression and its underlying mechanisms in vitro were investigated. KIR2.1-carried currents were measured by single-cell patch-clamp electrophysiology. KIR2.1 protein expression levels were determined by Western blot analysis, whereas conventional immunofluorescence and advanced live-imaging microscopy were used to assess the subcellular localization of KIR2.1 proteins. Acute propafenone treatment at low concentrations supports the ability of propafenone to function as an AgoKir without disturbing KIR2.1 protein handling. Chronic propafenone treatment (at 25-100 times higher concentrations than in the acute treatment) increases KIR2.1 protein expression and KIR2.1 current densities in vitro, which are potentially associated with pre-lysosomal trafficking inhibition.
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Affiliation(s)
- Encan Li
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Willy Kool
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Liset Woolschot
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
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17
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Iijima A, Švecová O, Hošek J, Kula R, Bébarová M. Sildenafil affects the human Kir2.1 and Kir2.2 channels at clinically relevant concentrations: Inhibition potentiated by low Ba 2. Front Pharmacol 2023; 14:1136272. [PMID: 36817146 PMCID: PMC9932908 DOI: 10.3389/fphar.2023.1136272] [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: 01/02/2023] [Accepted: 01/23/2023] [Indexed: 02/05/2023] Open
Abstract
Sildenafil (Viagra), the first approved and widely used oral drug for the treatment of erectile dysfunction, was occasionally associated with life-threatening ventricular arrhythmias in patients. Since inward rectifier potassium current (I K1) may considerably contribute to this arrhythmogenesis, we investigated the effect of sildenafil on the human Kir2.1 and Kir2.2, the prevailing subunits forming the ventricular I K1 channels. Experiments were performed by the whole-cell patch clamp technique at 37°C using Chinese hamster ovary cells transiently expressing the human Kir2.1 and Kir2.2 channels. Changes of both the inward and outward current components (at -110 and -50 mV, respectively) were tested to be able to consider the physiological relevance of the sildenafil effect (changes at -110 and -50 mV did not significantly differ, results at -50 mV are listed below). A significant Kir2.1 inhibition was observed at all applied sildenafil concentrations (16.1% ± 3.7%, 20.0% ± 2.6%, and 15.0% ± 3.0% at 0.1, 1, and 10 μM, respectively). The inhibitory effect of 0.1 μM sildenafil was potentiated by the presence of a low concentration of Ba2+ (0.1 μM) which induced only a slight Kir2.1 inhibition by 5.95% ± 0.75% alone (the combined effect was 35.5% ± 3.4%). The subtherapeutic and therapeutic sildenafil concentrations (0.1 and 1 μM) caused a dual effect on Kir2.2 channels whereas a significant Kir2.2 activation was observed at the supratherapeutic sildenafil concentration (10 μM: 34.1% ± 5.6%). All effects were fully reversible. This is the first study demonstrating that sildenafil at clinically relevant concentrations inhibits both the inward and outward current components of the main human ventricular I K1 subunit Kir2.1. This inhibitory effect was significantly potentiated by a low concentration of environmental contaminant Ba2+ in agreement with recently reported data on rat ventricular I K1 which additionally showed a significant repolarization delay. Considering the similar subunit composition of the human and rat ventricular I K1 channels, the observed effects might contribute to sildenafil-associated arrhythmogenesis in clinical practice.
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Affiliation(s)
- Akimasa Iijima
- Department of Physiology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Olga Švecová
- Department of Physiology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Jan Hošek
- Department of Molecular Pharmacy, Faculty of Pharmacy, Masaryk University, Brno, Czech Republic
| | - Roman Kula
- Department of Physiology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Markéta Bébarová
- Department of Physiology, Faculty of Medicine, Masaryk University, Brno, Czech Republic,*Correspondence: Markéta Bébarová,
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18
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Park S, Heo W, Shin SW, Kim HJ, Yoo YM, Kim HY. General anesthesia using propofol infusion for implantation of an implantable cardioverter defibrillator in a pediatric patient with Andersen-Tawil syndrome: a case report. J Dent Anesth Pain Med 2023; 23:45-51. [PMID: 36819605 PMCID: PMC9911964 DOI: 10.17245/jdapm.2023.23.1.45] [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: 10/18/2022] [Revised: 12/04/2022] [Accepted: 12/11/2022] [Indexed: 02/05/2023] Open
Abstract
Andersen-Tawil syndrome (ATS) is a rare genetic disease characterized by a triad of episodic flaccid muscle weakness, ventricular arrhythmias, and physical anomalies. ATS patients have various cardiac arrhythmias that can cause sudden death. Implantation of an implantable cardioverter-defibrillator (ICD) is required when life-threatening cardiac arrhythmias do not respond to medical treatment. An 11-year-old girl underwent surgery for an ICD implantation. For general anesthesia in ATS patients, anesthesiologists should focus on the potentially difficult airway, serious cardiac arrhythmias, such as ventricular tachycardia (VT), and delayed recovery from neuromuscular blockade. We followed the difficult airway algorithm, avoided drugs that can precipitate QT prolongation and fatal cardiac arrhythmias, and tried to maintain normoxia, normocarbia, normothermia, normoglycemia, and pain control for prevention of sympathetic stimulation. We report the successful application of general anesthesia for ICD implantation in a pediatric patient with ATS and recurrent VT.
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Affiliation(s)
- Seyeon Park
- Department of Anesthesia and Pain Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea
| | - Wonjae Heo
- Department of Anesthesia and Pain Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea
| | - Sang-Wook Shin
- Department of Anesthesia and Pain Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea.,Department of Anesthesia and Pain Medicine, School of Medicine, Pusan National University, Yangsan, Republic of Korea
| | - Hye-Jin Kim
- Department of Anesthesia and Pain Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea
| | - Yeong Min Yoo
- Department of Anesthesia and Pain Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea
| | - Hee Young Kim
- Department of Anesthesia and Pain Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea.,Department of Anesthesia and Pain Medicine, School of Medicine, Pusan National University, Yangsan, Republic of Korea
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19
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Arlock P, Li M, Davis B, Lövdahl C, Liao Q, Sjöberg T, Rahman A, Wohlfart B, Steen S, Arner A. Excitation and contraction of cardiac muscle and coronary arteries of brain-dead pigs. FASEB Bioadv 2022; 5:71-84. [PMID: 36816513 PMCID: PMC9927844 DOI: 10.1096/fba.2022-00104] [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: 10/10/2022] [Revised: 12/04/2022] [Accepted: 12/09/2022] [Indexed: 12/14/2022] Open
Abstract
Excitability and contraction of cardiac muscle from brain-dead donors critically influence the success of heart transplantation. Membrane physiology, Ca2+-handling, and force production of cardiac muscle and the contractile properties of coronary arteries were studied in hearts of brain-dead pigs. Cardiac muscle and vascular function after 12 h brain death (decapitation between C2 and C3) were compared with properties of fresh tissue. In both isolated cardiomyocytes (whole-cell patch clamp) and trabecular muscle (conventional microelectrodes), action potential duration was shorter in brain dead, compared to controls. Cellular shortening and Ca2+ transients were attenuated in the brain dead, and linked to lower mRNA expression of L-type calcium channels and a slightly lower ICa,L, current, as well as to a lower expression of phospholamban. The current-voltage relationship and the current above the equilibrium potential of the inward K+ (IK1) channel were altered in the brain-dead group, associated with lower mRNA expression of the Kir2.2 channel. Delayed K+ currents were detected (IKr, IKs) and were not different between groups. The transient outward K+ current (Ito) was not observed in the pig heart. Coronary arteries exhibited increased contractility and sensitivity to the thromboxane analogue (U46619), and unaltered endothelial relaxation. In conclusion, brain death involves changes in cardiac cellular excitation which might lower contractility after transplantation. Changes in the inward rectifier K+ channel can be associated with an increased risk for arrhythmia. Increased reactivity of coronary arteries may lead to increased risk of vascular spasm, although endothelial relaxant function was well preserved.
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Affiliation(s)
- Per Arlock
- Department of Clinical SciencesLund, Lund UniversityLundSweden,Department of Physiology and PharmacologyKarolinska InstitutetStockholmSweden
| | - Mei Li
- Department of Clinical SciencesLund, Lund UniversityLundSweden,Department of Physiology and PharmacologyKarolinska InstitutetStockholmSweden
| | - Benjamin Davis
- Department of Physiology and PharmacologyKarolinska InstitutetStockholmSweden
| | - Cecilia Lövdahl
- Department of Physiology and PharmacologyKarolinska InstitutetStockholmSweden
| | - Qiuming Liao
- Department of Clinical SciencesLund, Lund UniversityLundSweden
| | - Trygve Sjöberg
- Department of Clinical SciencesLund, Lund UniversityLundSweden
| | - Awahan Rahman
- Department of Physiology and PharmacologyKarolinska InstitutetStockholmSweden
| | - Björn Wohlfart
- Department of Clinical SciencesLund, Lund UniversityLundSweden
| | - Stig Steen
- Department of Clinical SciencesLund, Lund UniversityLundSweden
| | - Anders Arner
- Department of Clinical SciencesLund, Lund UniversityLundSweden,Department of Physiology and PharmacologyKarolinska InstitutetStockholmSweden
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20
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Xu Y, Yang Y, Chandrashekar A, Gada KD, Masotti M, Baggetta AM, Connolly JG, Kawano T, Plant LD. Hypoxia inhibits the cardiac I K1 current through SUMO targeting Kir2.1 activation by PIP 2. iScience 2022; 25:104969. [PMID: 36060074 PMCID: PMC9437851 DOI: 10.1016/j.isci.2022.104969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 05/07/2022] [Accepted: 08/12/2022] [Indexed: 11/30/2022] Open
Abstract
Cardiovascular diseases remain the leading cause of death worldwide. Most deaths are sudden and occur secondary to the occlusion of coronary arteries resulting in a rapid decrease in cellular oxygen levels. Acute hypoxia is proarrhythmic, leading to disordered electrical signals, conduction block, and uncoordinated beating of the myocardium. Although acute hypoxia is recognized to perturb the electrophysiology of heart muscle, the mechanistic basis for the effect has remained elusive, hampering the development of targeted therapeutic interventions. Here, we show that acute hypoxia activates the redox-sensitive SUMO pathway in cardiomyocytes, causing rapid inhibition of the inward-rectifying K+ channel, Kir2.1. We find that SUMOylation decreases the activation of Kir2.1 channels by the membrane phospholipid phosphatidylinositol 4,5-bisphosphate (PIP2). These data provide a mechanistic basis for the proarrhythmic effects of acute hypoxia and offer a framework for understanding the central role of PIP2 in mediating the sequelae of hypoxia and SUMOylation in cardiovascular disease.
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Affiliation(s)
- Yu Xu
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, MA, USA
| | - Yuchen Yang
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, MA, USA
| | - Aishwarya Chandrashekar
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, MA, USA
| | - Kirin D. Gada
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, MA, USA
| | - Meghan Masotti
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, MA, USA
| | - Austin M. Baggetta
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, MA, USA
| | - Jenna G. Connolly
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, MA, USA
| | - Takeharu Kawano
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, MA, USA
| | - Leigh D. Plant
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, MA, USA
- Center for Drug Discovery, Northeastern University, Boston, MA, USA
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21
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Sun W, Xu J, Wang L, Jiang Y, Cui J, Su X, Yang F, Tian L, Si Z, Xing Y. Non-coding RNAs in cancer therapy-induced cardiotoxicity: Mechanisms, biomarkers, and treatments. Front Cardiovasc Med 2022; 9:946137. [PMID: 36082126 PMCID: PMC9445363 DOI: 10.3389/fcvm.2022.946137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 07/28/2022] [Indexed: 02/06/2023] Open
Abstract
As a result of ongoing breakthroughs in cancer therapy, cancer patients' survival rates have grown considerably. However, cardiotoxicity has emerged as the most dangerous toxic side effect of cancer treatment, negatively impacting cancer patients' prognosis. In recent years, the link between non-coding RNAs (ncRNAs) and cancer therapy-induced cardiotoxicity has received much attention and investigation. NcRNAs are non-protein-coding RNAs that impact gene expression post-transcriptionally. They include microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). In several cancer treatments, such as chemotherapy, radiotherapy, and targeted therapy-induced cardiotoxicity, ncRNAs play a significant role in the onset and progression of cardiotoxicity. This review focuses on the mechanisms of ncRNAs in cancer therapy-induced cardiotoxicity, including apoptosis, mitochondrial damage, oxidative stress, DNA damage, inflammation, autophagy, aging, calcium homeostasis, vascular homeostasis, and fibrosis. In addition, this review explores potential ncRNAs-based biomarkers and therapeutic strategies, which may help to convert ncRNAs research into clinical practice in the future for early detection and improvement of cancer therapy-induced cardiotoxicity.
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Affiliation(s)
- Wanli Sun
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Juping Xu
- The Second People's Hospital of Jiaozuo, Jiaozuo, China
| | - Li Wang
- Department of Breast Surgery, Xingtai People's Hospital, Xingtai, China
| | - Yuchen Jiang
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Jingrun Cui
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Xin Su
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Fan Yang
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Li Tian
- Beijing University of Chinese Medicine, Beijing, China
| | - Zeyu Si
- The First Clinical Medical College of Shaanxi University of Chinese Medicine, Taiyuan, China
- Zeyu Si
| | - Yanwei Xing
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- *Correspondence: Yanwei Xing
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22
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Chen K, Hu YY, Wang LL, Xia Y, Jiang Q, Sun L, Qian SS, Wu JZ, Chen LQ, Li DS. Whole-Genome Sequencing Identified KCNJ12 and SLC25A5 Mutations in Port-Wine Stains. Front Med (Lausanne) 2022; 9:905902. [PMID: 35935790 PMCID: PMC9348515 DOI: 10.3389/fmed.2022.905902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 06/06/2022] [Indexed: 11/13/2022] Open
Abstract
Port-wine stains (PWSs) are a congenital capillary malformed disorder and are caused by a number of somatic mutations that disrupt vascular development. However, the underlying genetic mutations in the pathogenesis of PWS have not yet been fully elucidated. To understand PWS genetic variations and investigate novel genetic mutations, we extracted genomic DNA from four sporadic PWS patients and then performed whole-genome sequencing (WGS). Using Sorting Intolerant from Tolerant (SIFT), PolyPhen2, Mutation Assessor, MetaSVM to identify candidate genetic mutations and whole-exome sequencing (WES) to confirm the identified variants. We found a previously reported G protein subunit alpha q (GNAQ) mutation c.548G > A, p.Arg183Gln in one case, whereas no such mutation was found in the other three samples. Moreover, six novel somatic mutations in three genes, including KCNJ12, SLC25A5, POTEE, were found in these four samples. Importantly, WES also verified the KCNJ12 (c.433G > A, p.Gly145Ser) and SLC25A5 (c.413G > A, p.Arg138His) mutations in other five sporadic PWS patients, with the frequency of 60% (3 of 5) and 40% (2 of 5), respectively. Thus, we reveal in this study two novel somatic mutations, KCNJ12 and SLC25A5, in the sporadic PWS patients for the first time. These findings highlight the genetic polymorphism of PWS and provide potential clinical prediction targets for this disease.
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Affiliation(s)
- Kai Chen
- Hubei Key Laboratory of Infectious and Immune Skin Diseases, Wuhan No. 1 Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Department of Dermatology, Wuhan No. 1 Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yan-Yan Hu
- Department of Dermatology, Wuhan No. 1 Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Lin-Lin Wang
- Department of Dermatology, Wuhan No. 1 Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yun Xia
- Department of Dermatology, Wuhan No. 1 Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qian Jiang
- Department of Dermatology, Wuhan No. 1 Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Lan Sun
- Department of Dermatology, Wuhan No. 1 Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shan-Shan Qian
- Department of Dermatology, Wuhan No. 1 Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- School of Medicine, Jianghan University, Wuhan, China
| | - Jin-Zhao Wu
- Department of Dermatology, Wuhan No. 1 Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- School of Medicine, Jianghan University, Wuhan, China
| | - Liu-Qing Chen
- Hubei Key Laboratory of Infectious and Immune Skin Diseases, Wuhan No. 1 Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Department of Dermatology, Wuhan No. 1 Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Liu-Qing Chen,
| | - Dong-Sheng Li
- Hubei Key Laboratory of Infectious and Immune Skin Diseases, Wuhan No. 1 Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Department of Dermatology, Wuhan No. 1 Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- *Correspondence: Dong-Sheng Li,
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23
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Klein MG, Krantz MJ, Fatima N, Watters A, Colon-Sanchez D, Geiger RM, Goldstein RE, Solhjoo S, Mehler PS, Flagg TP, Haigney MC. Methadone Blockade of Cardiac Inward Rectifier K + Current Augments Membrane Instability and Amplifies U Waves on Surface ECGs: A Translational Study. J Am Heart Assoc 2022; 11:e023482. [PMID: 35658478 PMCID: PMC9238736 DOI: 10.1161/jaha.121.023482] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Background Methadone is associated with a disproportionate risk of sudden death and ventricular tachyarrhythmia despite only modest inhibition of delayed rectifier K+ current (IKr), the principal mechanism of drug-associated arrhythmia. Congenital defects of inward rectifier K+ current (IK1) have been linked to increased U-wave amplitude on ECG and fatal arrhythmia. We hypothesized that methadone may also be a potent inhibitor of IK1, contributing to delayed repolarization and manifesting on surface ECGs as augmented U-wave integrals. Methods and Results Using a whole-cell voltage clamp, methadone inhibited both recombinant and native IK1 with a half-maximal inhibitory concentration IC50) of 1.5 μmol/L, similar to that observed for IKr block (half-maximal inhibitory concentration of 2.9 μmol/L). Methadone modestly increased the action potential duration at 90% repolarization and slowed terminal repolarization at low concentrations. At higher concentrations, action potential duration at 90% repolarization lengthening was abolished, but its effect on terminal repolarization rose steadily and correlated with increased fluctuations of diastolic membrane potential. In parallel, patient ECGs were analyzed before and after methadone initiation, with 68% of patients having a markedly increased U-wave integral compared with premethadone (lead V3; mean +38%±15%, P=0.016), along with increased QT and TPeak to TEnd intervals, likely reflective of IKr block. Conclusions Methadone is a potent IK1 inhibitor that causes augmentation of U waves on surface ECG. We propose that increased membrane instability resulting from IK1 block may better explain methadone's arrhythmia risk beyond IKr inhibition alone. Drug-induced augmentation of U waves may represent evidence of blockade of multiple repolarizing ion channels, and evaluation of the effect of that agent on IK1 may be warranted.
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Affiliation(s)
- Michael G Klein
- Cardiology Division Department of Medicine Uniformed Services University Bethesda MD
| | - Mori J Krantz
- Denver Health Medical Center Cardiology Division Denver CO.,Department of Medicine University of Colorado School of Medicine Aurora CO.,Chief Science Advisor Cardiac Safety and Cardiovascular Imaging, Clario Inc. Philadelphia PA
| | - Naheed Fatima
- Department of Anatomy, Physiology & Genetics Uniformed Services University Bethesda MD
| | - Ashlie Watters
- ACUTE at Denver Health Denver CO.,Department of Medicine University of Colorado School of Medicine Aurora CO
| | - Dayan Colon-Sanchez
- Psychiatry Division Outpatient Behavioral Health Services, Denver Health, & University of Colorado School of Medicine Denver CO
| | - Robert M Geiger
- Department of Anatomy, Physiology & Genetics Uniformed Services University Bethesda MD
| | - Robert E Goldstein
- Cardiology Division Department of Medicine Uniformed Services University Bethesda MD
| | - Soroosh Solhjoo
- Cardiology Division Department of Medicine Uniformed Services University Bethesda MD.,Military Cardiovascular Outcomes Research (MiCOR) Bethesda MD
| | - Philip S Mehler
- ACUTE at Denver Health Denver CO.,Department of Medicine University of Colorado School of Medicine Aurora CO
| | - Thomas P Flagg
- Department of Anatomy, Physiology & Genetics Uniformed Services University Bethesda MD
| | - Mark C Haigney
- Cardiology Division Department of Medicine Uniformed Services University Bethesda MD.,Military Cardiovascular Outcomes Research (MiCOR) Bethesda MD
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24
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Lopez-Medina AI, Chahal CAA, Luzum JA. The genetics of drug-induced QT prolongation: evaluating the evidence for pharmacodynamic variants. Pharmacogenomics 2022; 23:543-557. [PMID: 35698903 DOI: 10.2217/pgs-2022-0027] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Drug-induced long QT syndrome (diLQTS) is an adverse effect of many commonly prescribed drugs, and it can increase the risk for lethal ventricular arrhythmias. Genetic variants in pharmacodynamic genes have been associated with diLQTS, but the strength of the evidence for each of those variants has not yet been evaluated. Therefore, the purpose of this review was to evaluate the strength of the evidence for pharmacodynamic genetic variants associated with diLQTS using a novel, semiquantitative scoring system modified from the approach used for congenital LQTS. KCNE1-D85N and KCNE2-T8A had definitive and strong evidence for diLQTS, respectively. The high level of evidence for these variants supports current consideration as risk factors for patients that will be prescribed a QT-prolonging drug.
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Affiliation(s)
- Ana I Lopez-Medina
- Department of Clinical Pharmacy, University of Michigan College of Pharmacy, Ann Arbor, MI 48109, USA
| | - Choudhary Anwar A Chahal
- Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA.,Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN 55905, USA.,Barts Heart Centre, St. Bartholomew's Hospital, West Smithfield, London, EC1A 7BE, UK.,WellSpan Health, Lancaster, PA 17607, USA
| | - Jasmine A Luzum
- Department of Clinical Pharmacy, University of Michigan College of Pharmacy, Ann Arbor, MI 48109, USA
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25
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Oshiyama NF, Pereira AHM, Cardoso AC, Franchini KG, Bassani JWM, Bassani RA. Developmental differences in myocardial transmembrane Na + transport: Implications for excitability and Na + handling. J Physiol 2022; 600:2651-2667. [PMID: 35489088 DOI: 10.1113/jp282661] [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: 11/29/2021] [Accepted: 04/20/2022] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Previous studies showed that myocardial preparations from immature rats are less sensitive to electrical field stimulation than adult preparations. Freshly-isolated ventricular myocytes from neonatal rats showed lower excitability than adult cells, e.g., less negative threshold membrane potential and greater membrane depolarization required for action potential triggering. In addition to differences in mRNA levels for Na+ channels isoforms and greater Na+ current (INa ) density, Na+ channel voltage-dependence was shifted to the right in immature myocytes, which seems to be sufficient to decrease excitability, according to computer simulations. Only in neonatal myocytes did cyclic activity promote marked cytosolic Na+ accumulation, which was prevented by abolition of systolic Ca2+ transients by blockade of Ca2+ currents. Developmental changes in INa may account for the difference in action potential initiation parameters, but not for cytosolic Na+ accumulation, which seems to be due mainly to Na+ /Ca2+ exchanger-mediated Na+ influx. ABSTRACT Little is currently known about possible developmental changes in myocardial Na+ handling, which may have impact on cell excitability and Ca2+ content. Resting intracellular Na+ concentration ([Na+ ]i ), measured in freshly-isolated rat ventricular myocytes with CoroNa-green, was not significantly different in neonates (3-5 days old) and adults, but electrical stimulation caused marked [Na+ ]i rise only in neonates. Inhibition of L-type Ca2+ current by CdCl2 abolished not only systolic Ca2+ transients, but also activity-dependent intracellular Na+ accumulation in immature cells. This indicates that the main Na+ influx pathway during activity is the Na+ /Ca2+ exchanger, rather than voltage-dependent Na+ current (INa ), which was not affected by CdCl2 . In immature myocytes, INa density was 2-fold greater, inactivation was faster, and the current peak occurred at less negative transmembrane potential (Em ) than in adults. Na+ channel steady-state activation and inactivation curves in neonates showed a rightward shift, which should increase channel availability at diastolic Em , but also require greater depolarization for excitation, which was observed experimentally and reproduced in computer simulations. Ventricular mRNA levels of Nav 1.1, Nav 1.4 and Nav 1.5 pore-forming isoforms were greater in neonate ventricles, while decrease was seen for the β1 subunit. Both molecular and biophysical changes in the channel profile may contribute to the differences in INa density and voltage-dependence, and also to the less negative threshold Em in neonates, compared to adults. The apparently lower excitability in immature ventricle may confer protection against the development of spontaneous activity in this tissue. Abstract figure legend Little is currently known about possible developmental changes in myocardial Na+ transport, which may have impact on cell excitability and other physiological aspects. At the mRNA level, neonatal rat ventricle expresses a greater variety of Na+ channel isoforms than in adults. In immature ventricular cardiomyocytes, Na+ current (INa ) density was greater, but voltage-dependence is shifted to less negative potentials than in adults. This should increase channel availability at diastolic membrane potential, but also require greater depolarization for excitation, which was observed experimentally and reproduced in computer simulation. We also observed that electrical stimulation caused marked intracellular Na+ accumulation only in neonates, which was abolished when Ca2+ transients and the Na+ /Ca2+ exchanger (NCX) were inhibited by Cd2+ + Ni2+ . Thus, it seems that the main Na+ influx pathway during activity in neonates is the NCX, rather than voltage-dependent INa , which was not affected by these blockers. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Natália F Oshiyama
- Department of Biomedical Engineering, School of Electrical and Computer Engineering, University of Campinas, Campinas, SP, Brazil.,National Laboratory for Cell Calcium Study, (LabNECC), Center for Biomedical Engineering, University of Campinas, Campinas, SP, Brazil
| | - Ana H M Pereira
- Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials (LNBio/CNPEM), Campinas, SP, Brazil
| | - Alisson C Cardoso
- Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials (LNBio/CNPEM), Campinas, SP, Brazil
| | - Kleber G Franchini
- Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials (LNBio/CNPEM), Campinas, SP, Brazil.,Department of Internal Medicine, School of Medicine, University of Campinas, Campinas, SP, Brazil
| | - José W M Bassani
- Department of Biomedical Engineering, School of Electrical and Computer Engineering, University of Campinas, Campinas, SP, Brazil.,National Laboratory for Cell Calcium Study, (LabNECC), Center for Biomedical Engineering, University of Campinas, Campinas, SP, Brazil
| | - Rosana A Bassani
- Department of Biomedical Engineering, School of Electrical and Computer Engineering, University of Campinas, Campinas, SP, Brazil.,National Laboratory for Cell Calcium Study, (LabNECC), Center for Biomedical Engineering, University of Campinas, Campinas, SP, Brazil
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26
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Macháček M, Švecová O, Bébarová M. Combination of Sildenafil and Ba2+ at a Low Concentration Show a Significant Synergistic Inhibition of Inward Rectifier Potassium Current Resulting in Action Potential Prolongation. Front Pharmacol 2022; 13:829952. [PMID: 35548367 PMCID: PMC9081525 DOI: 10.3389/fphar.2022.829952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 04/05/2022] [Indexed: 11/29/2022] Open
Abstract
Sildenafil (Viagra) is a vasodilator mainly used in the treatment of erectile dysfunction. Atrial or ventricular fibrillation may rarely occur as a side effect during sildenafil therapy. Although changes in inward rectifier potassium currents including IK1 are known to contribute to the pathogenesis of fibrillation, the effect of sildenafil on IK1 has not been studied. In experiments, Ba2+ is used as a specific inhibitor of IK1 at high concentrations (usually 100 µM). Being an environmental contaminant, it is also present in the human body; Ba2+ plasmatic concentrations up to 1.5 µM are usually reported in the general population. This study was primarily aimed to investigate changes of IK1 induced by sildenafil in a wide range of concentrations (0.1–100 µM). Additionally, the effect of combination of sildenafil and Ba2+ at selected clinically-relevant concentrations was tested, at 0.1 µM both on IK1 and on the action potential duration (APD). Experiments were performed by the whole-cell patch-clamp technique on enzymatically isolated rat ventricular cardiomyocytes, mostly at 23°C with the exception of APD measurements which were performed at 37°C as well. Sildenafil caused a significant, reversible, and concentration-dependent inhibition of IK1 that did not differ at −50 and −110 mV. Simultaneous application of sildenafil and Ba2+ at 0.1 µM revealed a massive inhibition of both inward and outward components of IK1 (this synergy was missing at other tested combinations). The combined effect at 0.1 µM (45.7 ± 5.7 and 43.0 ± 6.9% inhibition at −50 and −110 mV, respectively) was significantly higher than a simple sum of almost negligible effects of the individual substances and it led to a significant prolongation of APD at both 23 and 37°C. To our knowledge, similar potentiation of the drug-channel interaction has not been described. The observed massive inhibition of IK1 induced by a combined action of the vasodilator sildenafil and environmental contaminant Ba2+ at a low concentration and resulting in a significant APD prolongation may contribute to the genesis of arrhythmias observed in some patients treated with sildenafil.
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27
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Tomatidine-stimulated maturation of human embryonic stem cell-derived cardiomyocytes for modeling mitochondrial dysfunction. Exp Mol Med 2022; 54:493-502. [PMID: 35379934 PMCID: PMC9076832 DOI: 10.1038/s12276-022-00746-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 08/22/2021] [Accepted: 10/19/2021] [Indexed: 11/08/2022] Open
Abstract
Human embryonic stem cell-derived cardiomyocytes (hESC-CMs) have been reported to exhibit immature embryonic or fetal cardiomyocyte-like phenotypes. To enhance the maturation of hESC-CMs, we identified a natural steroidal alkaloid, tomatidine, as a new substance that stimulates the maturation of hESC-CMs. Treatment of human embryonic stem cells with tomatidine during cardiomyocyte differentiation stimulated the expression of several cardiomyocyte-specific markers and increased the density of T-tubules. Furthermore, tomatidine treatment augmented the number and size of mitochondria and enhanced the formation of mitochondrial lamellar cristae. Tomatidine treatment stimulated mitochondrial functions, including mitochondrial membrane potential, oxidative phosphorylation, and ATP production, in hESC-CMs. Tomatidine-treated hESC-CMs were more sensitive to doxorubicin-induced cardiotoxicity than the control cells. In conclusion, the present study suggests that tomatidine promotes the differentiation of stem cells to adult cardiomyocytes by accelerating mitochondrial biogenesis and maturation and that tomatidine-treated mature hESC-CMs can be used for cardiotoxicity screening and cardiac disease modeling.
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28
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Floy ME, Shabnam F, Simmons AD, Bhute VJ, Jin G, Friedrich WA, Steinberg AB, Palecek SP. Advances in Manufacturing Cardiomyocytes from Human Pluripotent Stem Cells. Annu Rev Chem Biomol Eng 2022; 13:255-278. [PMID: 35320695 DOI: 10.1146/annurev-chembioeng-092120-033922] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The emergence of human pluripotent stem cell (hPSC) technology over the past two decades has provided a source of normal and diseased human cells for a wide variety of in vitro and in vivo applications. Notably, hPSC-derived cardiomyocytes (hPSC-CMs) are widely used to model human heart development and disease and are in clinical trials for treating heart disease. The success of hPSC-CMs in these applications requires robust, scalable approaches to manufacture large numbers of safe and potent cells. Although significant advances have been made over the past decade in improving the purity and yield of hPSC-CMs and scaling the differentiation process from 2D to 3D, efforts to induce maturation phenotypes during manufacturing have been slow. Process monitoring and closed-loop manufacturing strategies are just being developed. We discuss recent advances in hPSC-CM manufacturing, including differentiation process development and scaling and downstream processes as well as separation and stabilization. Expected final online publication date for the Annual Review of Chemical and Biomolecular Engineering, Volume 13 is October 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Martha E Floy
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA; , , , , ,
| | - Fathima Shabnam
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA; , , , , ,
| | - Aaron D Simmons
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA; , , , , ,
| | - Vijesh J Bhute
- Department of Medical Genetics, University of Wisconsin-Madison, Madison, Wisconsin, USA; , .,Department of Chemical Engineering, Imperial College London, London, United Kingdom
| | - Gyuhyung Jin
- Department of Chemical Engineering, Purdue University, West Lafayette, Indiana, USA;
| | - Will A Friedrich
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA; , , , , ,
| | - Alexandra B Steinberg
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA; , , , , ,
| | - Sean P Palecek
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA; , , , , ,
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29
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Ramalho NJD, Švecová O, Kula R, Šimurdová M, Šimurda J, Bébarová M. Aminophylline at clinically relevant concentrations affects inward rectifier potassium current in a dual way. Pflugers Arch 2022; 474:303-313. [PMID: 35084562 DOI: 10.1007/s00424-021-02646-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 10/26/2021] [Accepted: 11/22/2021] [Indexed: 11/24/2022]
Abstract
Bronchodilator aminophylline may induce atrial or less often ventricular arrhythmias. The mechanism of this proarrhythmic side effect has not been fully explained. Modifications of inward rectifier potassium (Kir) currents including IK1 are known to play an important role in arrhythmogenesis; however, no data on the aminophylline effect on these currents have been published. Hence, we tested the effect of aminophylline (3-100 µM) on IK1 in enzymatically isolated rat ventricular myocytes using the whole-cell patch-clamp technique. A dual steady-state effect of aminophylline was observed; either inhibition or activation was apparent in individual cells during the application of aminophylline at a given concentration. The smaller the magnitude of the control IK1, the more likely the activation of the current by aminophylline and vice versa. The effect was reversible; the relative changes at -50 and -110 mV did not differ. Using IK1 channel population model, the dual effect was explained by the interaction of aminophylline with two different channel populations, the first one being inhibited and the second one being activated. Considering various fractions of these two channel populations in individual cells, varying effects observed in the measured cells could be simulated. We propose that the dual aminophylline effect may be related to the direct and indirect effect of the drug on various Kir2.x subunits forming the homo- and heterotetrameric IK1 channels in a single cell. The observed IK1 changes induced by clinically relevant concentrations of aminophylline might contribute to arrhythmogenesis related to the use of this bronchodilator in clinical medicine.
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Affiliation(s)
- Nuno Jorge Dourado Ramalho
- Department of Physiology, Faculty of Medicine, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic
| | - Olga Švecová
- Department of Physiology, Faculty of Medicine, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic
| | - Roman Kula
- Department of Physiology, Faculty of Medicine, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic.,Department of Paediatric Anaesthesiology and Intensive Care Medicine, Faculty of Medicine and University Hospital Brno, Masaryk University, Černopolní 9, 662 63, Brno, Czech Republic
| | - Milena Šimurdová
- Department of Physiology, Faculty of Medicine, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic
| | - Jiří Šimurda
- Department of Physiology, Faculty of Medicine, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic
| | - Markéta Bébarová
- Department of Physiology, Faculty of Medicine, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic.
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30
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Du C, Rasmusson RL, Bett GC, Franks B, Zhang H, Hancox JC. Investigation of the Effects of the Short QT Syndrome D172N Kir2.1 Mutation on Ventricular Action Potential Profile Using Dynamic Clamp. Front Pharmacol 2022; 12:794620. [PMID: 35115940 PMCID: PMC8806151 DOI: 10.3389/fphar.2021.794620] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 12/14/2021] [Indexed: 12/22/2022] Open
Abstract
The congenital short QT syndrome (SQTS) is a cardiac condition that leads to abbreviated ventricular repolarization and an increased susceptibility to arrhythmia and sudden death. The SQT3 form of the syndrome is due to mutations to the KCNJ2 gene that encodes Kir2.1, a critical component of channels underlying cardiac inwardly rectifying K+ current, IK1. The first reported SQT3 KCNJ2 mutation gives rise to the D172N Kir2.1 mutation, the consequences of which have been studied on recombinant channels in vitro and in ventricular cell and tissue simulations. The aim of this study was to establish the effects of the D172N mutation on ventricular repolarization through real-time replacement of IK1 using the dynamic clamp technique. Whole-cell patch-clamp recordings were made from adult guinea-pig left ventricular myocytes at physiological temperature. Action potentials (APs) were elicited at 1 Hz. Intrinsic IK1 was inhibited with a low concentration (50 µM) of Ba2+ ions, which led to AP prolongation and triangulation, accompanied by a ∼6 mV depolarization of resting membrane potential. Application of synthetic IK1 through dynamic clamp restored AP duration, shape and resting potential. Replacement of wild-type (WT) IK1 with heterozygotic (WT-D172N) or homozygotic (D172N) mutant formulations under dynamic clamp significantly abbreviated AP duration (APD90) and accelerated maximal AP repolarization velocity, with no significant hyperpolarization of resting potential. Across stimulation frequencies from 0.5 to 3 Hz, the relationship between APD90 and cycle length was downward shifted, reflecting AP abbreviation at all stimulation frequencies tested. In further AP measurements at 1 Hz from hiPSC cardiomyocytes, the D172N mutation produced similar effects on APD and repolarization velocity; however, resting potential was moderately hyperpolarized by application of mutant IK1 to these cells. Overall, the results of this study support the major changes in ventricular cell AP repolarization with the D172N predicted from prior AP modelling and highlight the potential utility of using adult ventricular cardiomyocytes for dynamic clamp exploration of functional consequences of Kir2.1 mutations.
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Affiliation(s)
- Chunyun Du
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Randall L. Rasmusson
- Department of Physiology and Biophysics, Jacobs School of Medicine and Biomedical Sciences, University of New York, University at Buffalo, Buffalo, NY, United States
- Cytocybernetics Inc, North Tonawanda, NY, United States
| | - Glenna C. Bett
- Department of Physiology and Biophysics, Jacobs School of Medicine and Biomedical Sciences, University of New York, University at Buffalo, Buffalo, NY, United States
- Cytocybernetics Inc, North Tonawanda, NY, United States
- Department of Obstetrics and Gynecology, Center for Cellular and Systems Electrophysiology, State University of New York, University at Buffalo, Buffalo, NY, United States
| | | | - Henggui Zhang
- Biological Physics Group, Department of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom
| | - Jules C. Hancox
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
- Biological Physics Group, Department of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom
- *Correspondence: Jules C. Hancox,
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31
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Koyani CN, Scheruebel S, Jin G, Kolesnik E, Zorn-Pauly K, Mächler H, Hoefler G, von Lewinski D, Heinzel FR, Pelzmann B, Malle E. Hypochlorite-Modified LDL Induces Arrhythmia and Contractile Dysfunction in Cardiomyocytes. Antioxidants (Basel) 2021; 11:25. [PMID: 35052529 PMCID: PMC8772905 DOI: 10.3390/antiox11010025] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/17/2021] [Accepted: 12/21/2021] [Indexed: 02/05/2023] Open
Abstract
Neutrophil-derived myeloperoxidase (MPO) and its potent oxidant, hypochlorous acid (HOCl), gained attention as important oxidative mediators in cardiac damage and dysfunction. As cardiomyocytes generate low-density lipoprotein (LDL)-like particles, we aimed to identify the footprints of proatherogenic HOCl-LDL, which adversely affects cellular signalling cascades in various cell types, in the human infarcted myocardium. We performed immunohistochemistry for MPO and HOCl-LDL in human myocardial tissue, investigated the impact of HOCl-LDL on electrophysiology and contractility in primary cardiomyocytes, and explored underlying mechanisms in HL-1 cardiomyocytes and human atrial appendages using immunoblot analysis, qPCR, and silencing experiments. HOCl-LDL reduced ICa,L and IK1, and increased INaL, leading to altered action potential characteristics and arrhythmic events including early- and delayed-afterdepolarizations. HOCl-LDL altered the expression and function of CaV1.2, RyR2, NCX1, and SERCA2a, resulting in impaired contractility and Ca2+ homeostasis. Elevated superoxide anion levels and oxidation of CaMKII were mediated via LOX-1 signaling in HL-1 cardiomyocytes. Furthermore, HOCl-LDL-mediated alterations of cardiac contractility and electrophysiology, including arrhythmic events, were ameliorated by the CaMKII inhibitor KN93 and the INaL blocker, ranolazine. This study provides an explanatory framework for the detrimental effects of HOCl-LDL compared to native LDL and cardiac remodeling in patients with high MPO levels during the progression of cardiovascular disease.
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Affiliation(s)
- Chintan N. Koyani
- Division of Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, 8010 Graz, Austria;
- Department of Internal Medicine, Division of Cardiology, Medical University of Graz, 8036 Graz, Austria; (G.J.); (E.K.); (D.v.L.)
| | - Susanne Scheruebel
- Division of Biophysics, Gottfried Schatz Research Center, Medical University of Graz, 8010 Graz, Austria; (S.S.); (K.Z.-P.)
| | - Ge Jin
- Department of Internal Medicine, Division of Cardiology, Medical University of Graz, 8036 Graz, Austria; (G.J.); (E.K.); (D.v.L.)
- The 2nd Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Ewald Kolesnik
- Department of Internal Medicine, Division of Cardiology, Medical University of Graz, 8036 Graz, Austria; (G.J.); (E.K.); (D.v.L.)
| | - Klaus Zorn-Pauly
- Division of Biophysics, Gottfried Schatz Research Center, Medical University of Graz, 8010 Graz, Austria; (S.S.); (K.Z.-P.)
| | - Heinrich Mächler
- Department of Surgery, Division of Cardiac Surgery, Medical University of Graz, 8036 Graz, Austria;
| | - Gerald Hoefler
- Diagnostic and Research Center for Molecular BioMedicine, Diagnostic and Research Institute of Pathology, Medical University of Graz, 8010 Graz, Austria;
| | - Dirk von Lewinski
- Department of Internal Medicine, Division of Cardiology, Medical University of Graz, 8036 Graz, Austria; (G.J.); (E.K.); (D.v.L.)
| | - Frank R. Heinzel
- Department of Internal Medicine and Cardiology, Charité-Universitätsmedizin Berlin, Campus Virchow-Klinikum, 13353 Berlin, Germany;
- Deutsches Zentrum für Herz-Kreislauf-Forschung (German Centre for Cardiovascular Research), Partner Site Berlin, 10785 Berlin, Germany
| | - Brigitte Pelzmann
- Division of Biophysics, Gottfried Schatz Research Center, Medical University of Graz, 8010 Graz, Austria; (S.S.); (K.Z.-P.)
| | - Ernst Malle
- Division of Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, 8010 Graz, Austria;
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Robinson VM, Alsalahat I, Freeman S, Antzelevitch C, Barajas-Martinez H, Venetucci L. A Carvedilol Analogue, VK-II-86, Prevents Hypokalaemia-induced Ventricular Arrhythmia through Novel multi-Channel Effects. Br J Pharmacol 2021; 179:2713-2732. [PMID: 34877651 DOI: 10.1111/bph.15775] [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: 01/19/2021] [Revised: 11/07/2021] [Accepted: 11/23/2021] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND AND PURPOSE QT prolongation and intracellular Ca2+ loading with diastolic Ca2+ release via ryanodine receptors (RyR2) are the predominant mechanisms underlying hypokalaemia-induced ventricular arrhythmia. We investigated the antiarrhythmic actions of two RyR2 inhibitors: dantrolene and VK-II-86, a carvedilol analogue with no β-blocking activity, in hypokalaemia. EXPERIMENTAL APPROACH Surface ECG and ventricular action potentials (APs) were recorded from whole-heart murine Langendorff preparations. Ventricular arrhythmia incidence was compared in hearts perfused with low [K+ ], and those pre-treated with dantrolene or VK-II-86. Whole-cell patch clamping was used in murine and canine ventricular cardiomyocytes to study the effects of dantrolene and VK-II-86 on AP parameters in low [K+ ] and the effects of VK-II-86 on the inward rectifier current (IK1 ), late sodium current (INa_L ) and the L-type Ca2+ current (ICa ). Effects of VK-II-86 on IKr were investigated in transfected HEK-293 cells. A fluorogenic probe quantified the effects of VK-II-86 on oxidative stress in hypokalaemia. KEY RESULTS Dantrolene reduced the incidence of ventricular arrhythmias induced by low [K+ ] in explanted murine hearts by 94%, whereas VK-II-86 prevented all arrhythmias. VK-II-86 prevented hypokalaemia-induced AP prolongation and depolarization, but did not alter AP parameters in normokalaemia. Hypokalaemia was associated with a significant reduction of IK1 and IKr , and increase in INa-L , and ICa . VK-II-86 prevented all hypokalaemia-induced changes in ion channel activity and oxidative stress. CONCLUSIONS AND IMPLICATIONS VK-II-86 prevents hypokalaemia-induced arrhythmogenesis by normalising calcium homeostasis and repolarization reserve. VK-II-86 may provide an exciting treatment in hypokalaemia and other arrhythmias caused by delayed repolarization or Ca2+ overload.
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Affiliation(s)
- Victoria M Robinson
- The University of Manchester, UK.,Lankenau Institute for Medical Research, Wynnewood, PA, USA
| | | | | | - Charles Antzelevitch
- Lankenau Institute for Medical Research, Wynnewood, PA, USA.,Sidney Kimmel College of Medicine, Thomas Jefferson University, Philadelphia, PA, USA.,Lankenau Heart Institute, Wynnewood, PA, USA
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Van de Sande DV, Kopljar I, Maaike A, Teisman A, Gallacher DJ, Bart L, Snyders DJ, Leybaert L, Lu HR, Labro AJ. The resting membrane potential of hSC-CM in a syncytium is more hyperpolarised than that of isolated cells. Channels (Austin) 2021; 15:239-252. [PMID: 33465001 PMCID: PMC7817136 DOI: 10.1080/19336950.2021.1871815] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 11/20/2020] [Accepted: 12/31/2020] [Indexed: 01/11/2023] Open
Abstract
Human-induced pluripotent stem cell (hiPSC) and stem cell (hSC) derived cardiomyocytes (CM) are gaining popularity as in vitro model for cardiology and pharmacology studies. A remaining flaw of these cells, as shown by single-cell electrophysiological characterization, is a more depolarized resting membrane potential (RMP) compared to native CM. Most reports attribute this to a lower expression of the Kir2.1 potassium channel that generates the IK1 current. However, most RMP recordings are obtained from isolated hSC/hiPSC-CMs whereas in a more native setting these cells are interconnected with neighboring cells by connexin-based gap junctions, forming a syncytium. Hereby, these cells are electrically connected and the total pool of IK1 increases. Therefore, the input resistance (Ri) of interconnected cells is lower than that of isolated cells. During patch clamp experiments pipettes need to be well attached or sealed to the cell, which is reflected in the seal resistance (Rs), because a nonspecific ionic current can leak through this pipette-cell contact or seal and balance out small currents within the cell such as IK1. By recording the action potential of isolated hSC-CMs and that of hSC-CMs cultured in small monolayers, we show that the RMP of hSC-CMs in monolayer is approximately -20 mV more hyperpolarized compared to isolated cells. Accordingly, adding carbenoxolone, a connexin channel blocker, isolates the cell that is patch clamped from its neighboring cells of the monolayer and depolarizes the RMP. The presented data show that the recorded RMP of hSC-CMs in a syncytium is more negative than that determined from isolated hSC/hiPSC-CMs, most likely because the active pool of Kir2.1 channels increased.
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Affiliation(s)
| | - Ivan Kopljar
- Global Safety Pharmacology, Non-Clinical Safety, Janssen R&D, Beerse, Belgium
| | - Alaerts Maaike
- Centre of Medical Genetics, University of Antwerp, Antwerp, Belgium
| | - Ard Teisman
- Global Safety Pharmacology, Non-Clinical Safety, Janssen R&D, Beerse, Belgium
| | - David J. Gallacher
- Global Safety Pharmacology, Non-Clinical Safety, Janssen R&D, Beerse, Belgium
| | - Loeys Bart
- Centre of Medical Genetics, University of Antwerp, Antwerp, Belgium
| | - Dirk J. Snyders
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Luc Leybaert
- Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - Hua Rong Lu
- Global Safety Pharmacology, Non-Clinical Safety, Janssen R&D, Beerse, Belgium
| | - Alain J. Labro
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
- Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
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Schmid C, Abi-Gerges N, Leitner MG, Zellner D, Rast G. Ion Channel Expression and Electrophysiology of Singular Human (Primary and Induced Pluripotent Stem Cell-Derived) Cardiomyocytes. Cells 2021; 10:3370. [PMID: 34943878 PMCID: PMC8699770 DOI: 10.3390/cells10123370] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 11/18/2021] [Accepted: 11/22/2021] [Indexed: 01/19/2023] Open
Abstract
Subtype-specific human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are promising tools, e.g., to assess the potential of drugs to cause chronotropic effects (nodal hiPSC-CMs), atrial fibrillation (atrial hiPSC-CMs), or ventricular arrhythmias (ventricular hiPSC-CMs). We used single-cell patch-clamp reverse transcriptase-quantitative polymerase chain reaction to clarify the composition of the iCell cardiomyocyte population (Fujifilm Cellular Dynamics, Madison, WI, USA) and to compare it with atrial and ventricular Pluricytes (Ncardia, Charleroi, Belgium) and primary human atrial and ventricular cardiomyocytes. The comparison of beating and non-beating iCell cardiomyocytes did not support the presence of true nodal, atrial, and ventricular cells in this hiPSC-CM population. The comparison of atrial and ventricular Pluricytes with primary human cardiomyocytes showed trends, indicating the potential to derive more subtype-specific hiPSC-CM models using appropriate differentiation protocols. Nevertheless, the single-cell phenotypes of the majority of the hiPSC-CMs showed a combination of attributes which may be interpreted as a mixture of traits of adult cardiomyocyte subtypes: (i) nodal: spontaneous action potentials and high HCN4 expression and (ii) non-nodal: prominent INa-driven fast inward current and high expression of SCN5A. This may hamper the interpretation of the drug effects on parameters depending on a combination of ionic currents, such as beat rate. However, the proven expression of specific ion channels supports the evaluation of the drug effects on ionic currents in a more realistic cardiomyocyte environment than in recombinant non-cardiomyocyte systems.
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Affiliation(s)
- Christina Schmid
- Drug Discovery Sciences, Boehringer Ingelheim Pharma GmbH & Co. KG, 88397 Biberach, Germany; (M.G.L.); (G.R.)
- Food Chemistry and Toxicology, Department of Chemistry, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | | | - Michael Georg Leitner
- Drug Discovery Sciences, Boehringer Ingelheim Pharma GmbH & Co. KG, 88397 Biberach, Germany; (M.G.L.); (G.R.)
| | - Dietmar Zellner
- Non-Clinical Statistics, Boehringer Ingelheim Pharma GmbH & Co. KG, 88397 Biberach, Germany
| | - Georg Rast
- Drug Discovery Sciences, Boehringer Ingelheim Pharma GmbH & Co. KG, 88397 Biberach, Germany; (M.G.L.); (G.R.)
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Estimating ectopic beat probability with simplified statistical models that account for experimental uncertainty. PLoS Comput Biol 2021; 17:e1009536. [PMID: 34665814 PMCID: PMC8577785 DOI: 10.1371/journal.pcbi.1009536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 11/09/2021] [Accepted: 10/06/2021] [Indexed: 11/21/2022] Open
Abstract
Ectopic beats (EBs) are cellular arrhythmias that can trigger lethal arrhythmias. Simulations using biophysically-detailed cardiac myocyte models can reveal how model parameters influence the probability of these cellular arrhythmias, however such analyses can pose a huge computational burden. Here, we develop a simplified approach in which logistic regression models (LRMs) are used to define a mapping between the parameters of complex cell models and the probability of EBs (P(EB)). As an example, in this study, we build an LRM for P(EB) as a function of the initial value of diastolic cytosolic Ca2+ concentration ([Ca2+]iini), the initial state of sarcoplasmic reticulum (SR) Ca2+ load ([Ca2+]SRini), and kinetic parameters of the inward rectifier K+ current (IK1) and ryanodine receptor (RyR). This approach, which we refer to as arrhythmia sensitivity analysis, allows for evaluation of the relationship between these arrhythmic event probabilities and their associated parameters. This LRM is also used to demonstrate how uncertainties in experimentally measured values determine the uncertainty in P(EB). In a study of the role of [Ca2+]SRini uncertainty, we show a special property of the uncertainty in P(EB), where with increasing [Ca2+]SRini uncertainty, P(EB) uncertainty first increases and then decreases. Lastly, we demonstrate that IK1 suppression, at the level that occurs in heart failure myocytes, increases P(EB). An ectopic beat is an abnormal cellular electrical event which can trigger dangerous arrhythmias in the heart. Complex biophysical models of the cardiac myocyte can be used to reveal how cell properties affect the probability of ectopic beats. However, such analyses can pose a huge computational burden. We develop a simplified approach that enables a highly complex biophysical model to be reduced to a rather simple statistical model from which the functional relationship between myocyte model parameters and the probability of an ectopic beat is determined. We refer to this approach as arrhythmia sensitivity analysis. Given the efficiency of our approach, we also use it to demonstrate how uncertainties in experimentally measured myocyte model parameters determine the uncertainty in ectopic beat probability. We find that, with increasing model parameter uncertainty, the uncertainty in probability of ectopic beat first increases and then decreases. In general, our approach can efficiently analyze the relationship between cardiac myocyte parameters and the probability of ectopic beats and can be used to study how uncertainty of these cardiac myocyte parameters influences the ectopic beat probability.
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Chen L, He Y, Wang X, Ge J, Li H. Ventricular voltage-gated ion channels: Detection, characteristics, mechanisms, and drug safety evaluation. Clin Transl Med 2021; 11:e530. [PMID: 34709746 PMCID: PMC8516344 DOI: 10.1002/ctm2.530] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 07/23/2021] [Accepted: 07/26/2021] [Indexed: 02/06/2023] Open
Abstract
Cardiac voltage-gated ion channels (VGICs) play critical roles in mediating cardiac electrophysiological signals, such as action potentials, to maintain normal heart excitability and contraction. Inherited or acquired alterations in the structure, expression, or function of VGICs, as well as VGIC-related side effects of pharmaceutical drug delivery can result in abnormal cellular electrophysiological processes that induce life-threatening cardiac arrhythmias or even sudden cardiac death. Hence, to reduce possible heart-related risks, VGICs must be acknowledged as important targets in drug discovery and safety studies related to cardiac disease. In this review, we first summarize the development and application of electrophysiological techniques that are employed in cardiac VGIC studies alone or in combination with other techniques such as cryoelectron microscopy, optical imaging and optogenetics. Subsequently, we describe the characteristics, structure, mechanisms, and functions of various well-studied VGICs in ventricular myocytes and analyze their roles in and contributions to both physiological cardiac excitability and inherited cardiac diseases. Finally, we address the implications of the structure and function of ventricular VGICs for drug safety evaluation. In summary, multidisciplinary studies on VGICs help researchers discover potential targets of VGICs and novel VGICs in heart, enrich their knowledge of the properties and functions, determine the operation mechanisms of pathological VGICs, and introduce groundbreaking trends in drug therapy strategies, and drug safety evaluation.
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Affiliation(s)
- Lulan Chen
- Department of Cardiology, Shanghai Institute of Cardiovascular DiseasesShanghai Xuhui District Central Hospital & Zhongshan‐xuhui Hospital, Zhongshan Hospital, Fudan UniversityShanghaiChina
| | - Yue He
- Department of CardiologyShanghai Xuhui District Central Hospital & Zhongshan‐xuhui HospitalShanghaiChina
| | - Xiangdong Wang
- Institute of Clinical Science, Zhongshan HospitalFudan UniversityShanghaiChina
| | - Junbo Ge
- Department of Cardiology, Shanghai Institute of Cardiovascular DiseasesShanghai Xuhui District Central Hospital & Zhongshan‐xuhui Hospital, Zhongshan Hospital, Fudan UniversityShanghaiChina
| | - Hua Li
- Department of Cardiology, Shanghai Institute of Cardiovascular DiseasesShanghai Xuhui District Central Hospital & Zhongshan‐xuhui Hospital, Zhongshan Hospital, Fudan UniversityShanghaiChina
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Disease Modeling of Mitochondrial Cardiomyopathy Using Patient-Specific Induced Pluripotent Stem Cells. BIOLOGY 2021; 10:biology10100981. [PMID: 34681080 PMCID: PMC8533352 DOI: 10.3390/biology10100981] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/25/2021] [Accepted: 09/26/2021] [Indexed: 12/15/2022]
Abstract
Mitochondrial cardiomyopathy (MCM) is characterized as an oxidative phosphorylation disorder of the heart. More than 100 genetic variants in nuclear or mitochondrial DNA have been associated with MCM. However, the underlying molecular mechanisms linking genetic variants to MCM are not fully understood due to the lack of appropriate cellular and animal models. Patient-specific induced pluripotent stem cell (iPSC)-derived cardiomyocytes (iPSC-CMs) provide an attractive experimental platform for modeling cardiovascular diseases and predicting drug efficacy to such diseases. Here we introduce the pathological and therapeutic studies of MCM using iPSC-CMs and discuss the questions and latest strategies for research using iPSC-CMs.
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38
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Déri S, Borbás J, Hartai T, Hategan L, Csányi B, Visnyovszki Á, Madácsy T, Maléth J, Hegedűs Z, Nagy I, Arora R, Labro AJ, Környei L, Varró A, Sepp R, Ördög B. Impaired cytoplasmic domain interactions cause co-assembly defect and loss of function in the p.Glu293Lys KNCJ2 variant isolated from an Andersen-Tawil syndrome patient. Cardiovasc Res 2021; 117:1923-1934. [PMID: 32810216 DOI: 10.1093/cvr/cvaa249] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 07/16/2020] [Accepted: 08/12/2020] [Indexed: 02/07/2023] Open
Abstract
AIMS Subunit interactions at the cytoplasmic domain interface (CD-I) have recently been shown to control gating in inward rectifier potassium channels. Here we report the novel KCNJ2 variant p.Glu293Lys that has been found in a patient with Andersen-Tawil syndrome type 1 (ATS1), causing amino acid substitution at the CD-I of the inward rectifier potassium channel subunit Kir2.1. Neither has the role of Glu293 in gating control been investigated nor has a pathogenic variant been described at this position. This study aimed to assess the involvement of Glu293 in CD-I subunit interactions and to establish the pathogenic role of the p.Glu293Lys variant in ATS1. METHODS AND RESULTS The p.Glu293Lys variant produced no current in homomeric form and showed dominant-negative effect over wild-type (WT) subunits. Immunocytochemical labelling showed the p.Glu293Lys subunits to distribute in the subsarcolemmal space. Salt bridge prediction indicated the presence of an intersubunit salt bridge network at the CD-I of Kir2.1, with the involvement of Glu293. Subunit interactions were studied by the NanoLuc® Binary Technology (NanoBiT) split reporter assay. Reporter constructs carrying NanoBiT tags on the intracellular termini produced no bioluminescent signal above background with the p.Glu293Lys variant in homomeric configuration and significantly reduced signals in cells co-expressing WT and p.Glu293Lys subunits simultaneously. Extracellularly presented reporter tags, however, generated comparable bioluminescent signals with heteromeric WT and p.Glu293Lys subunits and with homomeric WT channels. CONCLUSIONS Loss of function and dominant-negative effect confirm the causative role of p.Glu293Lys in ATS1. Co-assembly of Kir2.1 subunits is impaired in homomeric channels consisting of p.Glu293Lys subunits and is partially rescued in heteromeric complexes of WT and p.Glu293Lys Kir2.1 variants. These data point to an important role of Glu293 in mediating subunit assembly, as well as in gating of Kir2.1 channels.
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Affiliation(s)
- Szilvia Déri
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Dóm tér 12, PO Box 427, Szeged 6720, Hungary
- Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Dóm tér 12, 6720 Szeged, Hungary
| | - János Borbás
- 2nd Department of Internal Medicine and Cardiology Centre, University of Szeged, Semmelweis u. 8, 6725 Szeged, Hungary
| | - Teodóra Hartai
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Dóm tér 12, PO Box 427, Szeged 6720, Hungary
| | - Lidia Hategan
- 2nd Department of Internal Medicine and Cardiology Centre, University of Szeged, Semmelweis u. 8, 6725 Szeged, Hungary
| | - Beáta Csányi
- 2nd Department of Internal Medicine and Cardiology Centre, University of Szeged, Semmelweis u. 8, 6725 Szeged, Hungary
| | - Ádám Visnyovszki
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Dóm tér 12, PO Box 427, Szeged 6720, Hungary
| | - Tamara Madácsy
- 1st Department of Internal Medicine, University of Szeged, Korányi fasor 8-10, 6720 Szeged, Hungary, Hungary
| | - József Maléth
- 1st Department of Internal Medicine, University of Szeged, Korányi fasor 8-10, 6720 Szeged, Hungary, Hungary
| | - Zoltán Hegedűs
- Institute of Biophysics, Biological Research Centre of the Hungarian Academy of Sciences, Temesvári krt. 62, 6726 Szeged, Hungary
- Department of Biochemistry and Medical Chemistry, University of Pécs, Szigeti út 12, 7624 Pécs, Hungary
| | - István Nagy
- Institute of Biochemistry, Biological Research Centre the Hungarian Academy of Sciences, Temesvári krt. 62, 6726 Szeged, Hungary
- Seqomics Biotechnology Ltd, Vállalkozók útja 7, 6782 Mórahalom, Hungary
| | - Rohit Arora
- Department of Veterinary Sciences, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium
| | - Alain J Labro
- Department of Biomedical Sciences, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium
- Department of Basic Medical Sciences, University of Ghent, C. Heymanslaan 10, 9000 Ghent, Belgium
| | - László Környei
- Gottsegen György National Institute of Cardiology, Haller u. 9, 1096 Budapest, Hungary
| | - András Varró
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Dóm tér 12, PO Box 427, Szeged 6720, Hungary
- Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Dóm tér 12, 6720 Szeged, Hungary
- MTA-SZTE Research Group for Cardiovascular Pharmacology, Hungarian Academy of Sciences, Dóm tér 12, 6720 Szeged, Hungary
| | - Róbert Sepp
- 2nd Department of Internal Medicine and Cardiology Centre, University of Szeged, Semmelweis u. 8, 6725 Szeged, Hungary
| | - Balázs Ördög
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Dóm tér 12, PO Box 427, Szeged 6720, Hungary
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39
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Non-Coding RNAs in the Cardiac Action Potential and Their Impact on Arrhythmogenic Cardiac Diseases. HEARTS 2021. [DOI: 10.3390/hearts2030026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Cardiac arrhythmias are prevalent among humans across all age ranges, affecting millions of people worldwide. While cardiac arrhythmias vary widely in their clinical presentation, they possess shared complex electrophysiologic properties at cellular level that have not been fully studied. Over the last decade, our current understanding of the functional roles of non-coding RNAs have progressively increased. microRNAs represent the most studied type of small ncRNAs and it has been demonstrated that miRNAs play essential roles in multiple biological contexts, including normal development and diseases. In this review, we provide a comprehensive analysis of the functional contribution of non-coding RNAs, primarily microRNAs, to the normal configuration of the cardiac action potential, as well as their association to distinct types of arrhythmogenic cardiac diseases.
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40
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Electrophysiology of hiPSC-Cardiomyocytes Co-Cultured with HEK Cells Expressing the Inward Rectifier Channel. Int J Mol Sci 2021; 22:ijms22126621. [PMID: 34205607 PMCID: PMC8235371 DOI: 10.3390/ijms22126621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/07/2021] [Accepted: 06/11/2021] [Indexed: 11/23/2022] Open
Abstract
The immature electrophysiology of human-induced pluripotent stem cell-derived cardiomyocytes (hiCMs) complicates their use for therapeutic and pharmacological purposes. An insufficient inward rectifying current (IK1) and the presence of a funny current (if) cause spontaneous electrical activity. This study tests the hypothesis that the co-culturing of hiCMs with a human embryonic kidney (HEK) cell-line expressing the Kir2.1 channel (HEK-IK1) can generate an electrical syncytium with an adult-like cardiac electrophysiology. The mechanical activity of co-cultures using different HEK-IK1:hiCM ratios was compared with co-cultures using wildtype (HEK–WT:hiCM) or hiCM alone on days 3–8 after plating. Only ratios of 1:3 and 1:1 showed a significant reduction in spontaneous rate at days 4 and 6, suggesting that IK1 was influencing the electrophysiology. Detailed analysis at day 4 revealed an increased incidence of quiescent wells or sub-areas. Electrical activity showed a decreased action potential duration (APD) at 20% and 50%, but not at 90%, alongside a reduced amplitude of the aggregate AP signal. A computational model of the 1:1 co-culture replicates the electrophysiological effects of HEK–WT. The addition of the IK1 conductance reduced the spontaneous rate and APD20, 50 and 90, and minor variation in the intercellular conductance caused quiescence. In conclusion, a 1:1 co-culture HEK-IK1:hiCM caused changes in electrophysiology and spontaneous activity consistent with the integration of IK1 into the electrical syncytium. However, the additional electrical effects of the HEK cell at 1:1 increased the possibility of electrical quiescence before sufficient IK1 was integrated into the syncytium.
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41
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Clerx M, Mirams GR, Rogers AJ, Narayan SM, Giles WR. Immediate and Delayed Response of Simulated Human Atrial Myocytes to Clinically-Relevant Hypokalemia. Front Physiol 2021; 12:651162. [PMID: 34122128 PMCID: PMC8188899 DOI: 10.3389/fphys.2021.651162] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 03/22/2021] [Indexed: 12/18/2022] Open
Abstract
Although plasma electrolyte levels are quickly and precisely regulated in the mammalian cardiovascular system, even small transient changes in K+, Na+, Ca2+, and/or Mg2+ can significantly alter physiological responses in the heart, blood vessels, and intrinsic (intracardiac) autonomic nervous system. We have used mathematical models of the human atrial action potential (AP) to explore the electrophysiological mechanisms that underlie changes in resting potential (Vr) and the AP following decreases in plasma K+, [K+]o, that were selected to mimic clinical hypokalemia. Such changes may be associated with arrhythmias and are commonly encountered in patients (i) in therapy for hypertension and heart failure; (ii) undergoing renal dialysis; (iii) with any disease with acid-base imbalance; or (iv) post-operatively. Our study emphasizes clinically-relevant hypokalemic conditions, corresponding to [K+]o reductions of approximately 1.5 mM from the normal value of 4 to 4.5 mM. We show how the resulting electrophysiological responses in human atrial myocytes progress within two distinct time frames: (i) Immediately after [K+]o is reduced, the K+-sensing mechanism of the background inward rectifier current (IK1) responds. Specifically, its highly non-linear current-voltage relationship changes significantly as judged by the voltage dependence of its region of outward current. This rapidly alters, and sometimes even depolarizes, Vr and can also markedly prolong the final repolarization phase of the AP, thus modulating excitability and refractoriness. (ii) A second much slower electrophysiological response (developing 5-10 minutes after [K+]o is reduced) results from alterations in the intracellular electrolyte balance. A progressive shift in intracellular [Na+]i causes a change in the outward electrogenic current generated by the Na+/K+ pump, thereby modifying Vr and AP repolarization and changing the human atrial electrophysiological substrate. In this study, these two effects were investigated quantitatively, using seven published models of the human atrial AP. This highlighted the important role of IK1 rectification when analyzing both the mechanisms by which [K+]o regulates Vr and how the AP waveform may contribute to "trigger" mechanisms within the proarrhythmic substrate. Our simulations complement and extend previous studies aimed at understanding key factors by which decreases in [K+]o can produce effects that are known to promote atrial arrhythmias in human hearts.
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Affiliation(s)
- Michael Clerx
- Centre for Mathematical Medicine and Biology, School of Mathematical Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Gary R Mirams
- Centre for Mathematical Medicine and Biology, School of Mathematical Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Albert J Rogers
- Department of Medicine and Cardiovascular Institute, Stanford University, Stanford, CA, United States
| | - Sanjiv M Narayan
- Department of Medicine and Cardiovascular Institute, Stanford University, Stanford, CA, United States
| | - Wayne R Giles
- Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
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42
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Wilde AAM, Amin AS, Postema PG. Diagnosis, management and therapeutic strategies for congenital long QT syndrome. Heart 2021; 108:332-338. [PMID: 34039680 PMCID: PMC8862104 DOI: 10.1136/heartjnl-2020-318259] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 04/12/2021] [Accepted: 05/03/2021] [Indexed: 11/18/2022] Open
Abstract
Congenital long QT syndrome (LQTS) is characterised by heart rate corrected QT interval prolongation and life-threatening arrhythmias, leading to syncope and sudden death. Variations in genes encoding for cardiac ion channels, accessory ion channel subunits or proteins modulating the function of the ion channel have been identified as disease-causing mutations in up to 75% of all LQTS cases. Based on the underlying genetic defect, LQTS has been subdivided into different subtypes. Growing insights into the genetic background and pathophysiology of LQTS has led to the identification of genotype–phenotype relationships for the most common genetic subtypes, the recognition of genetic and non-genetic modifiers of phenotype, optimisation of risk stratification algorithms and the discovery of gene-specific therapies in LQTS. Nevertheless, despite these great advancements in the LQTS field, large gaps in knowledge still exist. For example, up to 25% of LQTS cases still remain genotype elusive, which hampers proper identification of family members at risk, and it is still largely unknown what determines the large variability in disease severity, where even within one family an identical mutation causes malignant arrhythmias in some carriers, while in other carriers, the disease is clinically silent. In this review, we summarise the current evidence available on the diagnosis, clinical management and therapeutic strategies in LQTS. We also discuss new scientific developments and areas of research, which are expected to increase our understanding of the complex genetic architecture in genotype-negative patients, lead to improved risk stratification in asymptomatic mutation carriers and more targeted (gene-specific and even mutation-specific) therapies.
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Affiliation(s)
- Arthur A M Wilde
- Heart Centre, Department of Cardiology, Amsterdam Universitair Medische Centra, Amsterdam, The Netherlands
| | - Ahmad S Amin
- Heart Centre, Department of Cardiology, Amsterdam Universitair Medische Centra, Amsterdam, The Netherlands
| | - Pieter G Postema
- Heart Centre, Department of Cardiology, Amsterdam Universitair Medische Centra, Amsterdam, The Netherlands
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43
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Garbern JC, Lee RT. Mitochondria and metabolic transitions in cardiomyocytes: lessons from development for stem cell-derived cardiomyocytes. Stem Cell Res Ther 2021; 12:177. [PMID: 33712058 PMCID: PMC7953594 DOI: 10.1186/s13287-021-02252-6] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 02/28/2021] [Indexed: 12/13/2022] Open
Abstract
Current methods to differentiate cardiomyocytes from human pluripotent stem cells (PSCs) inadequately recapitulate complete development and result in PSC-derived cardiomyocytes (PSC-CMs) with an immature or fetal-like phenotype. Embryonic and fetal development are highly dynamic periods during which the developing embryo or fetus is exposed to changing nutrient, oxygen, and hormone levels until birth. It is becoming increasingly apparent that these metabolic changes initiate developmental processes to mature cardiomyocytes. Mitochondria are central to these changes, responding to these metabolic changes and transitioning from small, fragmented mitochondria to large organelles capable of producing enough ATP to support the contractile function of the heart. These changes in mitochondria may not simply be a response to cardiomyocyte maturation; the metabolic signals that occur throughout development may actually be central to the maturation process in cardiomyocytes. Here, we review methods to enhance maturation of PSC-CMs and highlight evidence from development indicating the key roles that mitochondria play during cardiomyocyte maturation. We evaluate metabolic transitions that occur during development and how these affect molecular nutrient sensors, discuss how regulation of nutrient sensing pathways affect mitochondrial dynamics and function, and explore how changes in mitochondrial function can affect metabolite production, the cell cycle, and epigenetics to influence maturation of cardiomyocytes.
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Affiliation(s)
- Jessica C Garbern
- Department of Stem Cell and Regenerative Biology and the Harvard Stem Cell Institute, Harvard University, 7 Divinity Ave, Cambridge, MA, 02138, USA
- Department of Cardiology, Boston Children's Hospital, 300 Longwood Ave, Boston, MA, 02115, USA
| | - Richard T Lee
- Department of Stem Cell and Regenerative Biology and the Harvard Stem Cell Institute, Harvard University, 7 Divinity Ave, Cambridge, MA, 02138, USA.
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St, Boston, MA, 02115, USA.
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44
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Soattin L, Borbas Z, Caldwell J, Prendergast B, Vohra A, Saeed Y, Hoschtitzky A, Yanni J, Atkinson A, Logantha SJ, Borbas B, Garratt C, Morris GM, Dobrzynski H. Structural and Functional Properties of Subsidiary Atrial Pacemakers in a Goat Model of Sinus Node Disease. Front Physiol 2021; 12:592229. [PMID: 33746765 PMCID: PMC7969524 DOI: 10.3389/fphys.2021.592229] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 01/18/2021] [Indexed: 12/19/2022] Open
Abstract
Background The sinoatrial/sinus node (SAN) is the primary pacemaker of the heart. In humans, SAN is surrounded by the paranodal area (PNA). Although the PNA function remains debated, it is thought to act as a subsidiary atrial pacemaker (SAP) tissue and become the dominant pacemaker in the setting of sinus node disease (SND). Large animal models of SND allow characterization of SAP, which might be a target for novel treatment strategies for SAN diseases. Methods A goat model of SND was developed (n = 10) by epicardially ablating the SAN and validated by mapping of emergent SAP locations through an ablation catheter and surface electrocardiogram (ECG). Structural characterization of the goat SAN and SAP was assessed by histology and immunofluorescence techniques. Results When the SAN was ablated, SAPs featured a shortened atrioventricular conduction, consistent with the location in proximity of atrioventricular junction. SAP recovery time showed significant prolongation compared to the SAN recovery time, followed by a decrease over a follow-up of 4 weeks. Like the SAN tissue, the SAP expressed the main isoform of pacemaker hyperpolarization-activated cyclic nucleotide-gated channel 4 (HCN4) and Na+/Ca2+ exchanger 1 (NCX1) and no high conductance connexin 43 (Cx43). Structural characterization of the right atrium (RA) revealed that the SAN was located at the earliest activation [i.e., at the junction of the superior vena cava (SVC) with the RA] and was surrounded by the paranodal-like tissue, extending down to the inferior vena cava (IVC). Emerged SAPs were localized close to the IVC and within the thick band of the atrial muscle known as the crista terminalis (CT). Conclusions SAN ablation resulted in the generation of chronic SAP activity in 60% of treated animals. SAP displayed development over time and was located within the previously discovered PNA in humans, suggesting its role as dominant pacemaker in SND. Therefore, SAP in goat constitutes a promising stable target for electrophysiological modification to construct a fully functioning pacemaker.
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Affiliation(s)
- Luca Soattin
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Zoltan Borbas
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom.,Manchester Heart Centre, Central Manchester University Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom.,Liverpool Heart and Chest Hospital, Liverpool, United Kingdom
| | - Jane Caldwell
- Manchester Heart Centre, Central Manchester University Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom.,Hull University Teaching Hospitals, Hull, United Kingdom.,Hull York Medical School, Hull, United Kingdom
| | - Brian Prendergast
- Manchester Heart Centre, Central Manchester University Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Akbar Vohra
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom.,Manchester Heart Centre, Central Manchester University Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Yawer Saeed
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom.,Manchester Heart Centre, Central Manchester University Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom.,Department of Medicine, Aga Khan University, Karachi, Pakistan
| | - Andreas Hoschtitzky
- Adult Congenital Heart Disease Unit, Manchester Royal Infirmary, Manchester Academic Health Science Centre, Manchester, United Kingdom.,Royal Brompton Hospital, London, United Kingdom.,Imperial College London, London, United Kingdom
| | - Joseph Yanni
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Andrew Atkinson
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Sunil Jit Logantha
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom.,Liverpool Centre for Cardiovascular Sciences, Department of Cardiovascular and Metabolic Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Balint Borbas
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Clifford Garratt
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom.,Manchester Heart Centre, Central Manchester University Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Gwilym Matthew Morris
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom.,Manchester Heart Centre, Central Manchester University Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Halina Dobrzynski
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom.,Department of Anatomy, Jagiellonian University, Krakow, Poland
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45
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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: 3.0] [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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46
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Biliczki P, Boon RA, Girmatsion Z, Bukowska A, Ördög B, Kaess BM, Hohnloser SH, Goette A, Varró A, Moritz A, Nattel S, Ehrlich JR. Age-related regulation and region-specific distribution of ion channel subunits promoting atrial fibrillation in human left and right atria. Europace 2020; 21:1261-1269. [PMID: 31131392 DOI: 10.1093/europace/euz135] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Accepted: 04/23/2019] [Indexed: 12/13/2022] Open
Abstract
AIMS Age-induced changes and electrical remodelling are important components of the atrial fibrillation (AF) substrate. To study regional distribution and age-dependent changes in gene expression that may promote AF in human atria. METHODS AND RESULTS Human left atrial (LA) and right atrial (RA) tissue samples were obtained from donor hearts unsuitable for transplantation and from patients undergoing mitral valve repair. Atrial fibrillation was mimicked in vitro by tachypacing of human atrial tissue slices. Ionic currents were studied by the whole-cell patch-clamp technique; gene expression was analysed by real-time qPCR and immunoblotting. Both healthy RA and RA from older patients showed greater CACNA1c mRNA and CaV1.2 protein expression than LA. No age-dependent changes of Kir2.1 expression in both atria were seen. Remodelling occurred in a qualitatively similar manner in RA and LA. IK1 and Kir2.1 protein expression increased with AF. MiR-1, miR-26a, and miR-26b were down-regulated with AF in both atria. ICa,L was decreased. CACNA1c and CACNA2b expression decreased and miR-328 increased in RA and LA during AF. Ex vivo tachypacing of human atrial slices replicated these findings. There were age-dependent increases in miR-1 and miR-328, while miR-26a decreased with age in atrial tissues from healthy human donor hearts. CONCLUSION Features of electrical remodelling in man occur in a qualitatively similar manner in both human atria. Age-related miR-328 dysregulation and reduced ICa,L may contribute to increased AF susceptibility with age.
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Affiliation(s)
- Peter Biliczki
- Division of Cardiology, St.Josefs-Hospital, Beethovenstr. 20, Wiesbaden, Germany.,Division of Cardiology, Goethe-University, Frankfurt, Germany
| | - Reinier A Boon
- Institute for Cardiovascular Regeneration, Goethe-University, Frankfurt, Germany
| | | | - Alicia Bukowska
- Molekularpharmakologische Elektrophysiologie, Universitätsklinikum, Magdeburg, Germany
| | - Balázs Ördög
- Institute of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - Bernhard M Kaess
- Division of Cardiology, St.Josefs-Hospital, Beethovenstr. 20, Wiesbaden, Germany
| | | | - Andreas Goette
- Molekularpharmakologische Elektrophysiologie, Universitätsklinikum, Magdeburg, Germany
| | - András Varró
- Institute of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - Anton Moritz
- Cardiothoracic Surgery, Goethe-University, Frankfurt, Germany
| | - Stanley Nattel
- Research Center, Montreal Heart Institute and University of Montreal, Montreal, Canada
| | - Joachim R Ehrlich
- Division of Cardiology, St.Josefs-Hospital, Beethovenstr. 20, Wiesbaden, Germany.,Division of Cardiology, Goethe-University, Frankfurt, Germany
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47
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Varró A, Tomek J, Nagy N, Virág L, Passini E, Rodriguez B, Baczkó I. Cardiac transmembrane ion channels and action potentials: cellular physiology and arrhythmogenic behavior. Physiol Rev 2020; 101:1083-1176. [PMID: 33118864 DOI: 10.1152/physrev.00024.2019] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Cardiac arrhythmias are among the leading causes of mortality. They often arise from alterations in the electrophysiological properties of cardiac cells and their underlying ionic mechanisms. It is therefore critical to further unravel the pathophysiology of the ionic basis of human cardiac electrophysiology in health and disease. In the first part of this review, current knowledge on the differences in ion channel expression and properties of the ionic processes that determine the morphology and properties of cardiac action potentials and calcium dynamics from cardiomyocytes in different regions of the heart are described. Then the cellular mechanisms promoting arrhythmias in congenital or acquired conditions of ion channel function (electrical remodeling) are discussed. The focus is on human-relevant findings obtained with clinical, experimental, and computational studies, given that interspecies differences make the extrapolation from animal experiments to human clinical settings difficult. Deepening the understanding of the diverse pathophysiology of human cellular electrophysiology will help in developing novel and effective antiarrhythmic strategies for specific subpopulations and disease conditions.
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Affiliation(s)
- András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - Jakub Tomek
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Norbert Nagy
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - László Virág
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Elisa Passini
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Blanca Rodriguez
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
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48
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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: 3.0] [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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49
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Shimaoka T, Wang Y, Morishima M, Miyamoto S, Ono K. Magnesium Deficiency Causes Transcriptional Downregulation of Kir2.1 and Kv4.2 Channels in Cardiomyocytes Resulting in QT Interval Prolongation. Circ J 2020; 84:1244-1253. [DOI: 10.1253/circj.cj-20-0310] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Toru Shimaoka
- Department of Pathophysiology, Oita University School of Medicine
- Department of Cardiovascular Surgery, Oita University School of Medicine
| | - Yan Wang
- Department of Pathophysiology, Oita University School of Medicine
| | - Masaki Morishima
- Department of Pathophysiology, Oita University School of Medicine
| | - Shinji Miyamoto
- Department of Cardiovascular Surgery, Oita University School of Medicine
| | - Katsushige Ono
- Department of Pathophysiology, Oita University School of Medicine
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50
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Parrotta EI, Lucchino V, Scaramuzzino L, Scalise S, Cuda G. Modeling Cardiac Disease Mechanisms Using Induced Pluripotent Stem Cell-Derived Cardiomyocytes: Progress, Promises and Challenges. Int J Mol Sci 2020; 21:E4354. [PMID: 32575374 PMCID: PMC7352327 DOI: 10.3390/ijms21124354] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/12/2020] [Accepted: 06/15/2020] [Indexed: 12/12/2022] Open
Abstract
Cardiovascular diseases (CVDs) are a class of disorders affecting the heart or blood vessels. Despite progress in clinical research and therapy, CVDs still represent the leading cause of mortality and morbidity worldwide. The hallmarks of cardiac diseases include heart dysfunction and cardiomyocyte death, inflammation, fibrosis, scar tissue, hyperplasia, hypertrophy, and abnormal ventricular remodeling. The loss of cardiomyocytes is an irreversible process that leads to fibrosis and scar formation, which, in turn, induce heart failure with progressive and dramatic consequences. Both genetic and environmental factors pathologically contribute to the development of CVDs, but the precise causes that trigger cardiac diseases and their progression are still largely unknown. The lack of reliable human model systems for such diseases has hampered the unraveling of the underlying molecular mechanisms and cellular processes involved in heart diseases at their initial stage and during their progression. Over the past decade, significant scientific advances in the field of stem cell biology have literally revolutionized the study of human disease in vitro. Remarkably, the possibility to generate disease-relevant cell types from induced pluripotent stem cells (iPSCs) has developed into an unprecedented and powerful opportunity to achieve the long-standing ambition to investigate human diseases at a cellular level, uncovering their molecular mechanisms, and finally to translate bench discoveries into potential new therapeutic strategies. This review provides an update on previous and current research in the field of iPSC-driven cardiovascular disease modeling, with the aim of underlining the potential of stem-cell biology-based approaches in the elucidation of the pathophysiology of these life-threatening diseases.
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