Abstract
Human embryonic stem cell-derived cardiomyocytes (hESC-CMs) have become a promising cell source for cardiovascular research. The electrophysiological characteristic of hESC-CMs has been generally studied, but little is known about electrophysiological response to adrenergic adrenoreceptor (AR) activation. This study aims to characterize electrophysiological responses of hESC-CMs to adrenergic stimulation, in terms of the conduction velocity (CV) and action potential (AP) shape. The H9 hESC-CMs were acquired by a classical differentiation protocol and cultured to achieve confluent cell monolayers. The AP shape and CV among the monolayers were recorded using optical mapping during electrophysiological and pharmacological stimulation experiments. RT‐qPCR and Western blot were adopted to determine the expression levels of connexin and ion channel gene and protein. Chronic β-AR stimulation by isoproterenol for 24h in hESC-CMs monolayers increased CV by approximately 50%, while a-AR or acute β-AR stimulation had no significant effect; Chronic β-AR stimulation resulted in a significant Cx43 and Nav1.5 up-regulation at both protein and mRNA level. Isoproterenol induced CV accelerating and Cx43, Nav1.5 up-regulation in hESC-CMs, which was attenuated by selective β1-adrenoceptor antagonist CGP-20712A, but not selective β2-antagonist ICI-118551. Moreover, pretreatment with PKA inhibitor H89, MEK inhibitor SB203580 and MAPK inhibitor PD98059 suppressed the isoproterenol-induced CV accelerating and Cx43 up-regulation, whereas had no significant effect on Nav1.5 up-regulation. The AP shape in hESC-CMs monolayers was less susceptible by either β-AR or a-AR stimulation. It is β1-AR, not β2-AR contributing to the modification of conduction velocity among hESC‐CMs monolayers. Chronic β1-AR stimulation accelerates CV by up-regulating Cx43 via PKA/MEK/MAPK pathway.
SIGNIFICANCE STATEMENT These provide new insight into the electrophysiologic characteristics of human embryonic stem cell‐derived cardiomyocytes(hESC-CMs) and depict a concise signaling pathway in the ARs regulation of action potential shape and electrical propagation across hESCs-CMs monolayer. It is β1-AR, not β2-AR contributing to the modification of conduction velocity in hESC‐CMs and accelerates conduction velocity by up-regulating Cx43 via PKA/MEK/MAPK pathway.
- The American Society for Pharmacology and Experimental Therapeutics