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Contribution of potassium channels to action potential repolarization of human embryonic stem cell‐derived cardiomyocytes
Author(s) -
Wang Yin,
Zhu Renjun,
Tung Leslie
Publication year - 2019
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/bph.14704
Subject(s) - repolarization , embryonic stem cell , potassium channel , electrophysiology , cell culture , potassium channel blocker , microbiology and biotechnology , context (archaeology) , cardiac action potential , stem cell , chemistry , biology , medicine , endocrinology , neuroscience , biochemistry , genetics , gene , paleontology
Background and Purpose The electrophysiological properties of human pluripotent stem cell‐derived cardiomyocytes (CMs) have not yet been characterized in a syncytial context. This study systematically characterized the contributions of different repolarizing potassium currents in human embryonic stem cell‐derived CMs (hESC‐CMs) during long‐term culture as cell monolayers. Experimental Approach The H9 hESC line was differentiated to CMs and plated to form confluent cell monolayers. Optical mapping was used to record the action potentials (APs) and conduction velocity (CV) during electrophysiological and pharmacological experiments. RT‐PCR and Western blot were used to detect the presence and expression levels of ion channel subunits. Key Results Long‐term culture of hESC‐CMs led to shortened AP duration (APD), faster repolarization rate, and increased CV. Selective block of I Kr , I Ks , I K1 , and I Kur significantly affected AP repolarization and APD in a concentration‐ and culture time‐dependent manner. Baseline variations in APD led to either positive or negative APD dependence of drug response. Chromanol 293B produced greater relative AP prolongation in mid‐ and late‐stage cultures, while DPO‐1 had more effect in early‐stage cultures. CV in cell monolayers in early‐ and late‐stage cultures was most susceptible to slowing by E‐4031 and BaCl 2 respectively. Conclusions and Implications I Kr , I Ks , I K1 , and I Kur all play an essential role in the regulation of APD and CV in hESC‐CMs. During time in culture, increased expression of I Kr and I K1 helps to accelerate repolarization, shorten APD, and increase CV. We identified a new pro‐arrhythmic parameter, positive APD dependence of ion channel block, which can increase APD and repolarization gradients.