Contribution of two pore potassium channels to cardiac ventricular action potential revealed using human iPSC-derived cardiomyocytes.

Contribution of two pore potassium channels to cardiac ventricular action potential revealed using human iPSC-derived cardiomyocytes. Am J Physiol Heart Circ Physiol. 2017 Mar 24;:ajpheart.00107.2017 Authors: Chai S, Wan X, Nassal DM, Liu H, Moravec CS, Ramirez-Navarro A, Deschenes I Abstract Two pore potassium channels (K2p) have been described in modulating background conductance as leak channels in different physiological systems. In the heart, the expression of K2p channels is heterogeneous with equivocation regarding their functional role. Our objective was to determine the K2p expression profile and their physiological and pathophysiological contribution to cardiac electrophysiology. Induced pluripotent stem cells (iPSC) cells generated from humans were differentiated into cardiomyocytes (iPSC-CM). mRNA was isolated from these cells, commercial iPSC-CM (iCells®), control human heart ventricular tissue (cHVT), ischemic (iHF) and non-ischemic heart failure tissues (niHF). We detected ten K2p in the heart. Comparing qPCR expression of K2p between human heart tissue and iPSC-CM revealed K2p1.1, K2p2.1, K2p5.1, and K2p17.1 to be higher expressed in cHVT whereas K2p3.1 and K2p13.1 were higher in iPSC-CM. Notably, K2p17.1 was significantly lower in niHF tissues compared to cHVT. Action potential recordings in iCells® following K2p siRNA knockdown revealed prolongations in APD90 for K2p2.1, K2p3.1, K2p6.1, K2p17.1. Here we report the...
Source: American Journal of Physiology. Heart and Circulatory Physiology - Category: Physiology Authors: Tags: Am J Physiol Heart Circ Physiol Source Type: research