scholarly journals Human-induced pluripotent stem cell-derived cardiomyocytes have limited IKs for repolarization reserve as revealed by specific KCNQ1/KCNE1 blocker

2019 ◽  
Vol 8 ◽  
pp. 204800401985491 ◽  
Author(s):  
Haoyu Zeng ◽  
Jixin Wang ◽  
Holly Clouse ◽  
Armando Lagrutta ◽  
Frederick Sannajust
Keyword(s):  
Stem Cell ◽  
Action Potential ◽  
Action Potential Duration ◽  
Pluripotent Stem Cell ◽  
Synergistic Effects ◽  
Induced Pluripotent Stem Cell ◽  
Human Cardiomyocytes ◽  
Repolarization Reserve ◽  
Beating Rate ◽  
Induced Pluripotent

Objective We investigated if there is IKs, and if there is repolarization reserve by IKs in human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Design We used a specific KCNQ1/KCNE1 channel blocker, L-000768673, with an IC50 of 9 nM, and four hERG-specific blockers, astemizole, cisapride, dofetilide, and E-4031 to investigate the issue. Results L-000768673 concentration-dependently prolonged feature point duration (FPD)―a surrogate signal of action potential duration―from 1 to 30 nM without pacing or paced at 1.2 Hz, resulting from IKs blockade in hiPSC-CMs. At higher concentrations, the effect of L-000768673 on IKs was mitigated by its effect on ICa-L, resulting in shortened FPD, reduced impedance amplitude, and increased beating rate at 1 µM and above, recapitulating the self-limiting properties of L-000768673 on action potentials. All four hERG-specific blockers prolonged FPD as expected. Co-application of L-000768673 at sub-threshold (0.1 and 0.3 nM) and threshold (1 nM) concentrations failed to synergistically enhance the effects of hERG blockers on FPD prolongation, rather it showed additive effects, inconsistent with the repolarization reserve role of IKs in mature human myocytes that enhanced IKr response, implying a difference between hiPSC-CMs used in this study and mature human cardiomyocytes. Conclusion There was IKs current in hiPSC-CMs, and blockade of IKs current caused prolongation of action potential of hiPSC-CMs. However, we could not demonstrate any synergistic effects on action potential duration prolongation of hiPSC-CMs by blocking hERG current and IKs current simultaneously, implying little or no repolarization reserve by IKs current in hiPSC-CMs used in this study.

scholarly journals Dynamic Current Clamp Experiments Define the Functional Roles of IK1 and Ito,f in Human Induced Pluripotent Stem Cell Derived Cardiomyocytes

2017 ◽  
Author(s):  
Scott B. Marrus ◽  
Steven Springer ◽  
Eric Johnson ◽  
Rita J. Martinez ◽  
Edward J. Dranoff ◽  
...  
Keyword(s):  
Stem Cell ◽  
Action Potential ◽  
Action Potentials ◽  
Pluripotent Stem Cell ◽  
Phase 1 ◽  
Induced Pluripotent Stem Cell ◽  
Resting Membrane Potential ◽  
Current Clamp ◽  
Human Cardiomyocytes ◽  
Induced Pluripotent

AbstractThe transient outward potassium current (Ito) plays a key, albeit incompletely defined, role in cardiomyocyte physiology and pathophysiology. In light of the technical challenges of studying adult human cardiomyocytes, this study examines the use of induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) as a system which potentially preserves the native cellular milieu of human cardiomyocytes. ISPC-CMs express a robust Ito with slow recovery kinetics and fail to express the rapidly recovering Ito,f which is implicated in human disease. Overexpression of the accessory subunit KChIP2 (which is not expressed in iPSC-CMs) resulted in restoration of a rapid component of recovery. To define the functional role of Ito, dynamic current clamp was used to introduce computationally modeled currents into iPSC-CMs while recording action potentials. However, iPSC-CMs exhibit action potentials with multiple immature physiological properties, including slow upstroke velocity, heterogeneous action potential waveforms, and the absence of a phase 1 notch, thus potentially limiting the utility of these cells as a model of adult cardiomyocytes. Importantly, the introduction of modeled inwardly rectified current (IK1) ameliorated these immature properties by restoring a hyperpolarized resting membrane potential. In this context of normalized action potential morphologies, dynamic current clamp experiments introducing Ito,f demonstrated that there is significant cell-to-cell heterogeneity and that the functional effect of Ito,f is highly sensitive to the action potential plateau voltage in each cell.

scholarly journals Ion Channel Expression and Electrophysiology of Singular Human (Primary and Induced Pluripotent Stem Cell-Derived) Cardiomyocytes

Cells ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3370
Author(s):  
Christina Schmid ◽  
Najah Abi-Gerges ◽  
Michael Georg Leitner ◽  
Dietmar Zellner ◽  
Georg Rast
Keyword(s):  
Stem Cell ◽  
Single Cell ◽  
Pluripotent Stem Cell ◽  
Quantitative Polymerase Chain Reaction ◽  
Drug Effects ◽  
Induced Pluripotent Stem Cell ◽  
Ionic Currents ◽  
Human Cardiomyocytes ◽  
Ventricular Cells ◽  
Induced Pluripotent

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.

Assessment of Drug Proarrhythmic Potential in Electrically Paced Human Induced Pluripotent Stem Cell–Derived Ventricular Cardiomyocytes Using Multielectrode Array

2020 ◽  
pp. 247255522095320
Author(s):  
Shuyun Bai ◽  
Junjie Pei ◽  
Kan Chen ◽  
Ya Zhao ◽  
Henghua Cao ◽  
...  
Keyword(s):  
Stem Cell ◽  
Pluripotent Stem Cell ◽  
Field Potential ◽  
Induced Pluripotent Stem Cell ◽  
Multielectrode Array ◽  
Drug Induced ◽  
Ventricular Cardiomyocytes ◽  
Wide Range ◽  
Beating Rate ◽  
Induced Pluripotent

Human induced pluripotent stem cell–derived cardiomyocytes (hiPSC-CMs) have been widely used for the assessment of drug proarrhythmic potential through multielectrode array (MEA). HiPSC-CM cultures beat spontaneously with a wide range of frequencies, however, which could affect drug-induced changes in repolarization. Pacing hiPSC-CMs at a physiological heart rate more closely resembles the state of in vivo ventricular myocytes and permits the standardization of test conditions to improve consistency. In this study, we systematically investigated the time window of stable ion currents in high-purity hiPSC-derived ventricular cardiomyocytes (hiPSC-vCMs) and confirmed that these cells could be used to correctly predict the proarrhythmic risk of Comprehensive In Vitro Proarrhythmia Assay (CiPA) reference compounds. To evaluate drug proarrhythmic potentials at a physiological beating rate, we used a MEA to electrically pace hiPSC-vCMs, and we recorded regular field potential waveforms in hiPSC-vCMs treated with DMSO and 10 CiPA reference drugs. Prolongation of field potential duration was detected in cells after exposure to high- and intermediate-risk drugs; in addition, drug-induced arrhythmia-like events were observed. The results of this study provide a simple and feasible method to investigate drug proarrhythmic potentials in hiPSC-CMs at a physiological beating rate.

scholarly journals Protocol to measure contraction, calcium, and action potential in human-induced pluripotent stem cell-derived cardiomyocytes

2021 ◽  
Vol 2 (4) ◽  
pp. 100859
Author(s):  
Joe Z. Zhang ◽  
Shane Rui Zhao ◽  
Chengyi Tu ◽  
Paul Pang ◽  
Mao Zhang ◽  
...  
Keyword(s):  
Stem Cell ◽  
Action Potential ◽  
Pluripotent Stem Cell ◽  
Induced Pluripotent Stem Cell ◽  
Induced Pluripotent
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