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Clark AP, Krogh-Madsen T, Christini DJ. Stem cell-derived cardiomyocyte heterogeneity confounds electrophysiological insights. J Physiol 2024. [PMID: 38723234 DOI: 10.1113/jp284618] [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: 01/31/2024] [Accepted: 04/24/2024] [Indexed: 08/21/2024] Open
Abstract
Human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) offer potential as an in vitro model for studying drug cardiotoxicity and patient-specific cardiovascular disease. The inherent electrophysiological heterogeneity of these cells limits the depth of insights that can be drawn from well-designed experiments. In this review, we provide our perspective on some sources and the consequences of iPSC-CM heterogeneity. We demonstrate the extent of heterogeneity in the literature and explain how such heterogeneity is exacerbated by patch-clamp experimental artifacts in the manual and automated set-up. Finally, we discuss how this heterogeneity, caused by both intrinsic and extrinsic factors, limits our ability to build digital twins of patient-derived cardiomyocytes.
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Affiliation(s)
- Alexander P Clark
- Department of Biomedical Engineering, Cornell University, Ithaca, NY, USA
| | - Trine Krogh-Madsen
- Department of Physiology & Biophysics, Weill Cornell Medicine, New York, NY, USA
- Institute for Computational Biomedicine, Weill Cornell Medicine, New York, NY, USA
| | - David J Christini
- Department of Biomedical Engineering, Cornell University, Ithaca, NY, USA
- Department of Physiology and Pharmacology, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
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2
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Clark AP, Wei S, Fullerton K, Krogh-Madsen T, Christini DJ. Single-cell ionic current phenotyping explains stem cell-derived cardiomyocyte action potential morphology. Am J Physiol Heart Circ Physiol 2024; 326:H1146-H1154. [PMID: 38488520 PMCID: PMC11380975 DOI: 10.1152/ajpheart.00063.2024] [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: 02/01/2024] [Revised: 02/26/2024] [Accepted: 03/01/2024] [Indexed: 04/14/2024]
Abstract
Human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) are a promising tool to study arrhythmia-related factors, but the variability of action potential (AP) recordings from these cells limits their use as an in vitro model. In this study, we use recently published brief (10 s), dynamic voltage-clamp (VC) data to provide mechanistic insights into the ionic currents contributing to AP heterogeneity; we call this approach rapid ionic current phenotyping (RICP). Features of this VC data were correlated to AP recordings from the same cells, and we used computational models to generate mechanistic insights into cellular heterogeneity. This analysis uncovered several interesting links between AP morphology and ionic current density: both L-type calcium and sodium currents contribute to upstroke velocity, rapid delayed rectifier K+ current is the main determinant of the maximal diastolic potential, and an outward current in the activation range of slow delayed rectifier K+ is the main determinant of AP duration. Our analysis also identified an outward current in several cells at 6 mV that is not reproduced by iPSC-CM mathematical models but contributes to determining AP duration. RICP can be used to explain how cell-to-cell variability in ionic currents gives rise to AP heterogeneity. Because of its brief duration (10 s) and ease of data interpretation, we recommend the use of RICP for single-cell patch-clamp experiments that include the acquisition of APs.NEW & NOTEWORTHY We present rapid ionic current phenotyping (RICP), a current quantification approach based on an optimized voltage-clamp protocol. The method captures a rich snapshot of the ionic current dynamics, providing quantitative information about multiple currents (e.g., ICa,L, IKr) in the same cell. The protocol helped to identify key ionic determinants of cellular action potential heterogeneity in iPSC-CMs. This included unexpected results, such as the critical role of IKr in establishing the maximum diastolic potential.
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Affiliation(s)
- Alexander P Clark
- Department of Biomedical Engineering, Cornell University, Ithaca, New York, United States
| | - Siyu Wei
- Department of Physiology and Pharmacology, SUNY Downstate Health Sciences University, Brooklyn, New York, United States
| | - Kristin Fullerton
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, New York, United States
| | - Trine Krogh-Madsen
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, New York, United States
- Institute for Computational Biomedicine, Weill Cornell Medicine, New York, New York, United States
| | - David J Christini
- Department of Biomedical Engineering, Cornell University, Ithaca, New York, United States
- Department of Physiology and Pharmacology, SUNY Downstate Health Sciences University, Brooklyn, New York, United States
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3
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Seibertz F, Voigt N. High-throughput methods for cardiac cellular electrophysiology studies: the road to personalized medicine. Am J Physiol Heart Circ Physiol 2024; 326:H938-H949. [PMID: 38276947 PMCID: PMC11279751 DOI: 10.1152/ajpheart.00599.2023] [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: 09/26/2023] [Revised: 01/22/2024] [Accepted: 01/22/2024] [Indexed: 01/27/2024]
Abstract
Personalized medicine refers to the tailored application of medical treatment at an individual level, considering the specific genotype or phenotype of each patient for targeted therapy. In the context of cardiovascular diseases, implementing personalized medicine is challenging due to the high costs involved and the slow pace of identifying the pathogenicity of genetic variants, deciphering molecular mechanisms of disease, and testing treatment approaches. Scalable cellular models such as human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) serve as useful in vitro tools that reflect individual patient genetics and retain clinical phenotypes. High-throughput functional assessment of these constructs is necessary to rapidly assess cardiac pathogenicity and test new therapeutics if personalized medicine is to become a reality. High-throughput photometry recordings of single cells coupled with potentiometric probes offer cost-effective alternatives to traditional patch-clamp assessments of cardiomyocyte action potential characteristics. Importantly, automated patch-clamp (APC) is rapidly emerging in the pharmaceutical industry and academia as a powerful method to assess individual membrane-bound ionic currents and ion channel biophysics over multiple cells in parallel. Now amenable to primary cell and hiPSC-CM measurement, APC represents an exciting leap forward in the characterization of a multitude of molecular mechanisms that underlie clinical cardiac phenotypes. This review provides a summary of state-of-the-art high-throughput electrophysiological techniques to assess cardiac electrophysiology and an overview of recent works that successfully integrate these methods into basic science research that could potentially facilitate future implementation of personalized medicine at a clinical level.
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Affiliation(s)
- Fitzwilliam Seibertz
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Göttingen, Germany
- German Center for Cardiovascular Research (DZHK), partner site Göttingen, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells," Georg-August University Göttingen, Göttingen, Germany
- Nanion Technologies, GmbH, Munich, Germany
| | - Niels Voigt
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Göttingen, Germany
- German Center for Cardiovascular Research (DZHK), partner site Göttingen, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells," Georg-August University Göttingen, Göttingen, Germany
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4
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Butler AS, Ascione R, Marrion NV, Harmer SC, Hancox JC. In situ monolayer patch clamp of acutely stimulated human iPSC-derived cardiomyocytes promotes consistent electrophysiological responses to SK channel inhibition. Sci Rep 2024; 14:3185. [PMID: 38326449 PMCID: PMC10850090 DOI: 10.1038/s41598-024-53571-6] [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: 05/26/2023] [Accepted: 02/02/2024] [Indexed: 02/09/2024] Open
Abstract
Human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) represent an in vitro model of cardiac function. Isolated iPSC-CMs, however, exhibit electrophysiological heterogeneity which hinders their utility in the study of certain cardiac currents. In the healthy adult heart, the current mediated by small conductance, calcium-activated potassium (SK) channels (ISK) is atrial-selective. Functional expression of ISK within atrial-like iPSC-CMs has not been explored thoroughly. The present study therefore aimed to investigate atrial-like iPSC-CMs as a model system for the study of ISK. iPSCs were differentiated using retinoic acid (RA) to produce iPSC-CMs which exhibited an atrial-like phenotype (RA-iPSC-CMs). Only 18% of isolated RA-iPSC-CMs responded to SK channel inhibition by UCL1684 and isolated iPSC-CMs exhibited substantial cell-to-cell electrophysiological heterogeneity. This variability was significantly reduced by patch clamp of RA-iPSC-CMs in situ as a monolayer (iPSC-ML). A novel method of electrical stimulation was developed to facilitate recording from iPSC-MLs via In situ Monolayer Patch clamp of Acutely Stimulated iPSC-CMs (IMPASC). Using IMPASC, > 95% of iPSC-MLs could be paced at a 1 Hz. In contrast to isolated RA-iPSC-CMs, 100% of RA-iPSC-MLs responded to UCL1684, with APD50 being prolonged by 16.0 ± 2.0 ms (p < 0.0001; n = 12). These data demonstrate that in conjunction with IMPASC, RA-iPSC-MLs represent an improved model for the study of ISK. IMPASC may be of wider value in the study of other ion channels that are inconsistently expressed in isolated iPSC-CMs and in pharmacological studies.
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Affiliation(s)
- Andrew S Butler
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, UK
| | - Raimondo Ascione
- Bristol Heart Institute and Translational Biomedical Research Centre, Faculty of Health Science, University of Bristol, Bristol, BS2 8HW, UK
| | - Neil V Marrion
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, UK
| | - Stephen C Harmer
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, UK.
| | - Jules C Hancox
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, UK.
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5
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Heijman J, Christ T. Mind the gap: leak currents and induced pluripotent stem cell-derived cardiomyocytes in translational cardiac electrophysiology. Europace 2023; 25:euad236. [PMID: 37522360 PMCID: PMC10445299 DOI: 10.1093/europace/euad236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 07/26/2023] [Accepted: 07/28/2023] [Indexed: 08/01/2023] Open
Affiliation(s)
- Jordi Heijman
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Faculty of Health, Medicine, and Life Sciences, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, The Netherlands
| | - Torsten Christ
- Institute of Experimental Pharmacology and Toxicology, University Medical Centre Hamburg-Eppendorf, Martinistraße 52, 20251 Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Martinistraße 52, 20251 Hamburg, Germany
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6
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Clark AP, Clerx M, Wei S, Lei CL, de Boer TP, Mirams GR, Christini DJ, Krogh-Madsen T. Leak current, even with gigaohm seals, can cause misinterpretation of stem cell-derived cardiomyocyte action potential recordings. Europace 2023; 25:euad243. [PMID: 37552789 PMCID: PMC10445319 DOI: 10.1093/europace/euad243] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 06/18/2023] [Indexed: 08/10/2023] Open
Abstract
AIMS Human-induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) have become an essential tool to study arrhythmia mechanisms. Much of the foundational work on these cells, as well as the computational models built from the resultant data, has overlooked the contribution of seal-leak current on the immature and heterogeneous phenotype that has come to define these cells. The aim of this study is to understand the effect of seal-leak current on recordings of action potential (AP) morphology. METHODS AND RESULTS Action potentials were recorded in human iPSC-CMs using patch clamp and simulated using previously published mathematical models. Our in silico and in vitro studies demonstrate how seal-leak current depolarizes APs, substantially affecting their morphology, even with seal resistances (Rseal) above 1 GΩ. We show that compensation of this leak current is difficult due to challenges with obtaining accurate measures of Rseal during an experiment. Using simulation, we show that Rseal measures (i) change during an experiment, invalidating the use of pre-rupture values, and (ii) are polluted by the presence of transmembrane currents at every voltage. Finally, we posit that the background sodium current in baseline iPSC-CM models imitates the effects of seal-leak current and is increased to a level that masks the effects of seal-leak current on iPSC-CMs. CONCLUSION Based on these findings, we make recommendations to improve iPSC-CM AP data acquisition, interpretation, and model-building. Taking these recommendations into account will improve our understanding of iPSC-CM physiology and the descriptive ability of models built from such data.
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Affiliation(s)
- Alexander P Clark
- Department of Biomedical Engineering, Cornell University, Ithaca, NY, USA
| | - Michael Clerx
- Centre for Mathematical Medicine and Biology, School of Mathematical Sciences, University of Nottingham, Nottingham, UK
| | - Siyu Wei
- Department of Physiology and Pharmacology, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
| | - Chon Lok Lei
- Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau, China
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Macau, Macau, China
| | - Teun P de Boer
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Gary R Mirams
- Centre for Mathematical Medicine and Biology, School of Mathematical Sciences, University of Nottingham, Nottingham, UK
| | - David J Christini
- Department of Biomedical Engineering, Cornell University, Ithaca, NY, USA
- Department of Physiology and Pharmacology, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
| | - Trine Krogh-Madsen
- Department of Physiology and Biophysics, Weill Cornell Medicine, 1300 York Avenue, Box 75, Room C501D, New York, 10065 NY, USA
- Institute for Computational Biomedicine, Weill Cornell Medicine, 1300 York Avenue, Box 75, Room C501D, New York, 10065 NY, USA
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Van de Sande D, Ghasemi M, Watters T, Burton F, Pham L, Altrocchi C, Gallacher DJ, Lu H, Smith G. Does Enhanced Structural Maturity of hiPSC-Cardiomyocytes Better for the Detection of Drug-Induced Cardiotoxicity? Biomolecules 2023; 13:676. [PMID: 37189424 PMCID: PMC10135569 DOI: 10.3390/biom13040676] [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: 03/03/2023] [Revised: 04/03/2023] [Accepted: 04/11/2023] [Indexed: 05/17/2023] Open
Abstract
Human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs) are currently used following the Comprehensive in vitro Proarrhythmic Assay (CiPA) initiative and subsequent recommendations in the International Council for Harmonization (ICH) guidelines S7B and E14 Q&A, to detect drug-induced cardiotoxicity. Monocultures of hiPSC-CMs are immature compared to adult ventricular cardiomyocytes and might lack the native heterogeneous nature. We investigated whether hiPSC-CMs, treated to enhance structural maturity, are superior in detecting drug-induced changes in electrophysiology and contraction. This was achieved by comparing hiPSC-CMs cultured in 2D monolayers on the current standard (fibronectin matrix, FM), to monolayers on a coating known to promote structural maturity (CELLvo™ Matrix Plus, MM). Functional assessment of electrophysiology and contractility was made using a high-throughput screening approach involving the use of both voltage-sensitive fluorescent dyes for electrophysiology and video technology for contractility. Using 11 reference drugs, the response of the monolayer of hiPSC-CMs was comparable in the two experimental settings (FM and MM). The data showed no functionally relevant differences in electrophysiology between hiPSC-CMs in standard FM and MM, while contractility read-outs indicated an altered amplitude of contraction but not changes in time course. RNA profiling for cardiac proteins shows similarity of the RNA expression across the two forms of 2D culture, suggesting that cell-to-matrix adhesion differences may explain account for differences in contraction amplitude. The results support the view that hiPSC-CMs in both 2D monolayer FM and MM that promote structural maturity are equally effective in detecting drug-induced electrophysiological effects in functional safety studies.
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Affiliation(s)
- Dieter Van de Sande
- Global Safety Pharmacology, Nonclinical Safety, Janssen Pharmaceutical NV, B-2340 Beerse, Belgium
| | - Mohammadreza Ghasemi
- School of Cardiovascular & Metabolic Health, College of Medical, Veterinary & Life Sciences, University of Glasgow, 126 University Place, Glasgow G12 8TA, UK
- Clyde Biosciences Limited, BioCity Scotland, Lanarkshire ML1 5UH, Scotland, UK
| | - Taylor Watters
- School of Cardiovascular & Metabolic Health, College of Medical, Veterinary & Life Sciences, University of Glasgow, 126 University Place, Glasgow G12 8TA, UK
- Clyde Biosciences Limited, BioCity Scotland, Lanarkshire ML1 5UH, Scotland, UK
| | - Francis Burton
- School of Cardiovascular & Metabolic Health, College of Medical, Veterinary & Life Sciences, University of Glasgow, 126 University Place, Glasgow G12 8TA, UK
- Clyde Biosciences Limited, BioCity Scotland, Lanarkshire ML1 5UH, Scotland, UK
| | - Ly Pham
- Global Safety Pharmacology, Nonclinical Safety, Janssen Pharmaceutical NV, B-2340 Beerse, Belgium
| | - Cristina Altrocchi
- Global Safety Pharmacology, Nonclinical Safety, Janssen Pharmaceutical NV, B-2340 Beerse, Belgium
| | - David J. Gallacher
- Global Safety Pharmacology, Nonclinical Safety, Janssen Pharmaceutical NV, B-2340 Beerse, Belgium
| | - Huarong Lu
- Global Safety Pharmacology, Nonclinical Safety, Janssen Pharmaceutical NV, B-2340 Beerse, Belgium
| | - Godfrey Smith
- School of Cardiovascular & Metabolic Health, College of Medical, Veterinary & Life Sciences, University of Glasgow, 126 University Place, Glasgow G12 8TA, UK
- Clyde Biosciences Limited, BioCity Scotland, Lanarkshire ML1 5UH, Scotland, UK
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Ismaili D, Schulz C, Horváth A, Koivumäki JT, Mika D, Hansen A, Eschenhagen T, Christ T. Human induced pluripotent stem cell-derived cardiomyocytes as an electrophysiological model: Opportunities and challenges-The Hamburg perspective. Front Physiol 2023; 14:1132165. [PMID: 36875015 PMCID: PMC9978010 DOI: 10.3389/fphys.2023.1132165] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 02/06/2023] [Indexed: 02/18/2023] Open
Abstract
Models based on human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) are proposed in almost any field of physiology and pharmacology. The development of human induced pluripotent stem cell-derived cardiomyocytes is expected to become a step forward to increase the translational power of cardiovascular research. Importantly they should allow to study genetic effects on an electrophysiological background close to the human situation. However, biological and methodological issues revealed when human induced pluripotent stem cell-derived cardiomyocytes were used in experimental electrophysiology. We will discuss some of the challenges that should be considered when human induced pluripotent stem cell-derived cardiomyocytes will be used as a physiological model.
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Affiliation(s)
- Djemail Ismaili
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Department of Cardiology, University Heart and Vascular Center Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Carl Schulz
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - András Horváth
- Translational Cardiology, Department of Cardiology, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland
| | - Jussi T. Koivumäki
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Delphine Mika
- Inserm, UMR-S 1180, Université Paris-Saclay, Orsay, France
| | - Arne Hansen
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Thomas Eschenhagen
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Torsten Christ
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany
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9
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Nijak A, Simons E, Vandendriessche B, Van de Sande D, Fransen E, Sieliwończyk E, Van Gucht I, Van Craenenbroeck E, Saenen J, Heidbuchel H, Ponsaerts P, Labro AJ, Snyders D, De Vos W, Schepers D, Alaerts M, Loeys BL. Morpho-functional comparison of differentiation protocols to create iPSC-derived cardiomyocytes. Biol Open 2022; 11:274508. [PMID: 35195246 PMCID: PMC8890088 DOI: 10.1242/bio.059016] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 12/15/2021] [Indexed: 11/30/2022] Open
Abstract
Cardiomyocytes derived from induced pluripotent stem cells (iPSC-CMs) offer an attractive platform for cardiovascular research. Patient-specific iPSC-CMs are very useful for studying disease development, and bear potential for disease diagnostics, prognosis evaluation and development of personalized treatment. Several monolayer-based serum-free protocols have been described for the differentiation of iPSCs into cardiomyocytes, but data on their performance are scarce. In this study, we evaluated two protocols that are based on temporal modulation of the Wnt/β-catenin pathway for iPSC-CM differentiation from four iPSC lines, including two control individuals and two patients carrying an SCN5A mutation. The SCN5A gene encodes the cardiac voltage-gated sodium channel (Nav1.5) and loss-of-function mutations can cause the cardiac arrhythmia Brugada syndrome. We performed molecular characterization of the obtained iPSC-CMs by immunostaining for cardiac specific markers and by expression analysis of selected cardiac structural and ionic channel protein-encoding genes with qPCR. We also investigated cell growth morphology, contractility and survival of the iPSC-CMs after dissociation. Finally, we performed electrophysiological characterization of the cells, focusing on the action potential (AP) and calcium transient (CT) characteristics using patch-clamping and optical imaging, respectively. Based on our comprehensive morpho-functional analysis, we concluded that both tested protocols result in a high percentage of contracting CMs. Moreover, they showed acceptable survival and cell quality after dissociation (>50% of cells with a smooth cell membrane, possible to seal during patch-clamping). Both protocols generated cells presenting with typical iPSC-CM AP and CT characteristics, although one protocol (that involves sequential addition of CHIR99021 and Wnt-C59) rendered iPSC-CMs, which were more accessible for patch-clamp and calcium transient experiments and showed an expression pattern of cardiac-specific markers more similar to this observed in human heart left ventricle samples. Summary: In this study, we evaluated two protocols that are based on temporal modulation of the Wnt/β -catenin pathway for iPSC-CM differentiation from four iPSC lines. We show that both protocols were successful in the generation of contracting iPSC-CMs. However, one of the tested protocols rendered cells that were more accessible for patch-clamp experiments and showed an expression pattern of cardiac-specific markers more similar to this of human heart left ventricle samples.
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Affiliation(s)
- Aleksandra Nijak
- Center of Medical Genetics, Faculty of Medicine and Health Sciences, University of Antwerp & Antwerp University Hospital, Antwerp 2650, Belgium
| | - Eline Simons
- Center of Medical Genetics, Faculty of Medicine and Health Sciences, University of Antwerp & Antwerp University Hospital, Antwerp 2650, Belgium
| | - Bert Vandendriessche
- Center of Medical Genetics, Faculty of Medicine and Health Sciences, University of Antwerp & Antwerp University Hospital, Antwerp 2650, Belgium
| | - Dieter Van de Sande
- Laboratory of Molecular Biophysics, Cellular and Network Excitability, Department of Biomedical Sciences, University of Antwerp, Antwerp 2610, Belgium
| | - Erik Fransen
- StatUa Center of Statistics, University of Antwerp 2650, Antwerp, Belgium
| | - Ewa Sieliwończyk
- Center of Medical Genetics, Faculty of Medicine and Health Sciences, University of Antwerp & Antwerp University Hospital, Antwerp 2650, Belgium
| | - Ilse Van Gucht
- Center of Medical Genetics, Faculty of Medicine and Health Sciences, University of Antwerp & Antwerp University Hospital, Antwerp 2650, Belgium
| | - Emeline Van Craenenbroeck
- Department of Cardiology, Faculty of Medicine and Health Sciences, University of Antwerp and Antwerp University Hospital, Antwerp 2650, Belgium
| | - Johan Saenen
- Department of Cardiology, Faculty of Medicine and Health Sciences, University of Antwerp and Antwerp University Hospital, Antwerp 2650, Belgium
| | - Hein Heidbuchel
- Department of Cardiology, Faculty of Medicine and Health Sciences, University of Antwerp and Antwerp University Hospital, Antwerp 2650, Belgium
| | - Peter Ponsaerts
- Laboratory of Experimental Hematology, Vaccine & Infectious Disease Institute, Department of Biomedical Sciences, University of Antwerp, Antwerp 2610, Belgium
| | - Alain J Labro
- Laboratory of Molecular Biophysics, Cellular and Network Excitability, Department of Biomedical Sciences, University of Antwerp, Antwerp 2610, Belgium.,Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent 9000, Belgium
| | - Dirk Snyders
- Laboratory of Molecular Biophysics, Cellular and Network Excitability, Department of Biomedical Sciences, University of Antwerp, Antwerp 2610, Belgium
| | - Winnok De Vos
- Laboratory of Cell Biology and Histology, Faculty of Veterinary Sciences, University of Antwerp, Antwerp 2610, Belgium
| | - Dorien Schepers
- Center of Medical Genetics, Faculty of Medicine and Health Sciences, University of Antwerp & Antwerp University Hospital, Antwerp 2650, Belgium.,Laboratory of Molecular Biophysics, Cellular and Network Excitability, Department of Biomedical Sciences, University of Antwerp, Antwerp 2610, Belgium
| | - Maaike Alaerts
- Center of Medical Genetics, Faculty of Medicine and Health Sciences, University of Antwerp & Antwerp University Hospital, Antwerp 2650, Belgium
| | - Bart L Loeys
- Center of Medical Genetics, Faculty of Medicine and Health Sciences, University of Antwerp & Antwerp University Hospital, Antwerp 2650, Belgium.,Department of Human Genetics, Radboud University Medical Centre, Nijmegen 6525, The Netherlands
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10
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Zhou M, Du Y, Aten S, Terman D. On the electrical passivity of astrocyte potassium conductance. J Neurophysiol 2021; 126:1403-1419. [PMID: 34525325 DOI: 10.1152/jn.00330.2021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Predominant expression of leak-type K+ channels provides astrocytes a high membrane permeability to K+ ions and a hyperpolarized membrane potential that are crucial for astrocyte function in brain homeostasis. In functionally mature astrocytes, the expression of leak K+ channels creates a unique membrane K+ conductance that lacks voltage-dependent rectification. Accordingly, the conductance is named ohmic or passive K+ conductance. Several inwardly rectifying and two-pore domain K+ channels have been investigated for their contributions to passive conductance. Meanwhile, gap junctional coupling has been postulated to underlie the passive behavior of membrane conductance. It is now clear that the intrinsic properties of K+ channels and gap junctional coupling can each act alone or together to bring about a passive behavior of astrocyte conductance. Additionally, while the passive conductance can generally be viewed as a K+ conductance, the actual representation of this conductance is a combined expression of multiple known and unknown K+ channels, which has been further modified by the intricate morphology of individual astrocytes and syncytial gap junctional coupling. The expression of the inwardly rectifying K+ channels explains the inward-going component of passive conductance disobeying Goldman-Hodgkin-Katz constant field outward rectification. However, the K+ channels encoding the outward-going passive currents remain to be determined in the future. Here, we review our current understanding of ion channels and biophysical mechanisms engaged in the passive astrocyte K+ conductance, propose new studies to resolve this long-standing puzzle in astrocyte physiology, and discuss the functional implication(s) of passive behavior of K+ conductance on astrocyte physiology.
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Affiliation(s)
- Min Zhou
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Yixing Du
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Sydney Aten
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, Ohio
| | - David Terman
- Department of Mathematics, Ohio State University, Columbus, Ohio
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Hawthorne RN, Blazeski A, Lowenthal J, Kannan S, Teuben R, DiSilvestre D, Morrissette-McAlmon J, Saffitz JE, Boheler KR, James CA, Chelko SP, Tomaselli G, Tung L. Altered Electrical, Biomolecular, and Immunologic Phenotypes in a Novel Patient-Derived Stem Cell Model of Desmoglein-2 Mutant ARVC. J Clin Med 2021; 10:jcm10143061. [PMID: 34300226 PMCID: PMC8306340 DOI: 10.3390/jcm10143061] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 07/05/2021] [Accepted: 07/08/2021] [Indexed: 12/27/2022] Open
Abstract
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a progressive heart condition which causes fibro-fatty myocardial scarring, ventricular arrhythmias, and sudden cardiac death. Most cases of ARVC can be linked to pathogenic mutations in the cardiac desmosome, but the pathophysiology is not well understood, particularly in early phases when arrhythmias can develop prior to structural changes. Here, we created a novel human induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) model of ARVC from a patient with a c.2358delA variant in desmoglein-2 (DSG2). These DSG2-mutant (DSG2Mut) hiPSC-CMs were compared against two wildtype hiPSC-CM lines via immunostaining, RT-qPCR, Western blot, RNA-Seq, cytokine expression and optical mapping. Mutant cells expressed reduced DSG2 mRNA and had altered localization of desmoglein-2 protein alongside thinner, more disorganized myofibrils. No major changes in other desmosomal proteins were noted. There was increased pro-inflammatory cytokine expression that may be linked to canonical and non-canonical NFκB signaling. Action potentials in DSG2Mut CMs were shorter with increased upstroke heterogeneity, while time-to-peak calcium and calcium decay rate were reduced. These were accompanied by changes in ion channel and calcium handling gene expression. Lastly, suppressing DSG2 in control lines via siRNA allowed partial recapitulation of electrical anomalies noted in DSG2Mut cells. In conclusion, the aberrant cytoskeletal organization, cytokine expression, and electrophysiology found DSG2Mut hiPSC-CMs could underlie early mechanisms of disease manifestation in ARVC patients.
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Affiliation(s)
- Robert N. Hawthorne
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; (R.N.H.); (A.B.); (J.L.); (S.K.); (R.T.); (J.M.-M.); (K.R.B.)
- Medical Scientist Training Program, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Adriana Blazeski
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; (R.N.H.); (A.B.); (J.L.); (S.K.); (R.T.); (J.M.-M.); (K.R.B.)
| | - Justin Lowenthal
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; (R.N.H.); (A.B.); (J.L.); (S.K.); (R.T.); (J.M.-M.); (K.R.B.)
- Medical Scientist Training Program, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Suraj Kannan
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; (R.N.H.); (A.B.); (J.L.); (S.K.); (R.T.); (J.M.-M.); (K.R.B.)
- Medical Scientist Training Program, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Roald Teuben
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; (R.N.H.); (A.B.); (J.L.); (S.K.); (R.T.); (J.M.-M.); (K.R.B.)
| | - Deborah DiSilvestre
- Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; (D.D.); (C.A.J.)
| | - Justin Morrissette-McAlmon
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; (R.N.H.); (A.B.); (J.L.); (S.K.); (R.T.); (J.M.-M.); (K.R.B.)
| | - Jeffrey E. Saffitz
- Department of Pathology, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA;
| | - Kenneth R. Boheler
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; (R.N.H.); (A.B.); (J.L.); (S.K.); (R.T.); (J.M.-M.); (K.R.B.)
- Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; (D.D.); (C.A.J.)
| | - Cynthia A. James
- Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; (D.D.); (C.A.J.)
| | - Stephen P. Chelko
- Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; (D.D.); (C.A.J.)
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306, USA
- Correspondence: (S.P.C.); (G.T.); (L.T.); Tel.: +1-850-644-2215 (S.P.C.); +1-718-430-2801 (G.T.); +1-410-955-9603 (L.T.)
| | - Gordon Tomaselli
- Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; (D.D.); (C.A.J.)
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Correspondence: (S.P.C.); (G.T.); (L.T.); Tel.: +1-850-644-2215 (S.P.C.); +1-718-430-2801 (G.T.); +1-410-955-9603 (L.T.)
| | - Leslie Tung
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; (R.N.H.); (A.B.); (J.L.); (S.K.); (R.T.); (J.M.-M.); (K.R.B.)
- Correspondence: (S.P.C.); (G.T.); (L.T.); Tel.: +1-850-644-2215 (S.P.C.); +1-718-430-2801 (G.T.); +1-410-955-9603 (L.T.)
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