Automated Patch Clamp & iPSC: Manual and Automated Patch Clamp measurements of IK1 currents in hiPSC-derived cardiomyocytes

Fitzwilliam Seibertz, University Medical Center Göttingen
The discovery that it is possible to restore pluripotency to somatic human cells has revolutionized the field of biological science and regenerative medicine. Human induced pluripotent stem cells (hiPSCs) are patient-specific, carry an inherent capacity for in vitro self-renewal and hold the potential to differentiate into several cell types, including cardiomyocytes (hiPSC-CMs). Over the years, the differentiation process has been honed to produce very pure populations of cardiomyocytes. However, these cells still display an immature electrophysiological phenotype characterized by a perceived lack of the inward rectifier: IK1. Using standard protocols, manual patch clamp techniques and in silico modelling, we observe a clear time course of inherent IK1 development in hiPSC-CM with wide-reaching effects on global cellular electrophysiology.

Kadla Rosholm, Sophion Bioscience A/S
Automated patch clamp (APC) measurements of hiPSC-CMs are inherently challenging due to cell quality (batch-batch variation, differentiation efficiency), cardiac maturity (presence of pacemaker current If, and reduced hyperpolarizing current, IK1) 6,7 and cell harvest (purity/quality of the single cell suspension). Improving on all three parameters, we were able to record cardiac voltage-gated currents (INa, ICa, IKr, IK1) with up to 50% success rates and paced action potentials with up to 20% success rates. The increased throughput of action potential measurements compared to manual patch clamp (10 cells per measurement plate) allowed us to measure the dose-response effects of standard compounds such as nifedipine, E4031 and Bay K8466. These measurements were performed in physiological solutions without the use of fluoride or other types of seal enhancers.