This webinar shows new applications on dynamic patch clamp of iPSC-derived cardiomyocytes and introduces an assay on KCa3.1 expressed in erythrocytes
Dr. Teun P. de Boer, Professor
Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht. Yalelaan 50, 3584 CM Utrecht, The Netherlands
Title: Dynamic clamping on a Patchliner: adding virtual IK1 channels to cardiomyocytes
Abstract: Human pluripotent stem cell-derived cardiomyocytes (hPSC-CM) are an interesting source of cells for safety pharmacology, but there are caveats that have to be taken into account. A typical property of hPSC-CM is automaticity, the cardiomyocytes beat spontaneously, resembling cells in the sinoatrial node of the heart. The spontaneous beating is due to lack of IK1 ion channels, which normally assure a stable resting membrane potential in cardiomyocytes. Work by our group has demonstrated that the depolarized state of hPSC-CM limits their usefulness in assays aimed at detecting proarrhythmic properties of drugs (Jonsson et al., 2012, PMID: 22353256).
Dynamic clamping can provide virtual, simulated IK1 channels to a real biological hPSC-CM in a patch clamping experiment. Key benefits of this approach include full control of the added IK1 conductance to each cardiomyocyte, it can be applied to any hPSC-CM source and it can be coupled to automated patch clamping machines. In this webinar I will discuss our work on using the dynamic clamping technique with a Patchliner.
Maria Giustina Rotordam
PhD student of Nanion Technologies GmbH, Munich, Germany
Title: Activation of hKCa3.1 by internal calcium exchange.
Abstract: The intermediate-conductance calcium-activated K+ channel, also known as KCa3.1, is a member of the large family of potassium channels gated by calcium. It can be distinguished from the other calcium-activated K+ channels by differences in channel conductance, calcium sensitivity, voltage dependence and pharmacological properties.
It is primarily expressed in peripheral tissues, including those of the hematopoietic system, colon, lung, placenta, and pancreas and is thought to be a promising therapeutic target for a variety of health disorders including sickle cell anaemia and immunological disorders. The Ca2+ -binding protein, calmodulin (CaM), is required for the activation of hKCa3.1. The Patchliner was used to perform a biophysical and pharmacological characterization of hKCa3.1 channels expressed in CHO cells. hKCa3.1 was activated by exchanging the internal solution to a solution containing free-Ca2+ and blocked by external application of non-selective (BaCl2) and selective (TRAM-34) inhibitors with an IC50 value consistent with that reported in the literature.
CHO cells stably expressing hKCa3.1 (Catalog # CT6123) were kindly supplied by Charles River.