1. Stem cell-derived cardiomyocytes expressing a dominant negative pacemaker HCN4 channel do not reduce the risk of graft-related arrhythmias
- Author
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Fanny Wulkan, Rocco Romagnuolo, Beiping Qiang, Tamilla Valdman Sadikov, Kyung-Phil Kim, Elya Quesnel, Wenlei Jiang, Naaz Andharia, Jill J. Weyers, Nilesh R. Ghugre, Bilgehan Ozcan, Faisal J. Alibhai, and Michael A. Laflamme
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pluripotent stem cells ,cardiomyocyte ,myocardial infarction ,cardiac regeneration ,cell engineering ,ion channel ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
BackgroundHuman pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) show tremendous promise for cardiac regeneration following myocardial infarction (MI), but their transplantation gives rise to transient ventricular tachycardia (VT) in large-animal MI models, representing a major hurdle to translation. Our group previously reported that these arrhythmias arise from a focal mechanism whereby graft tissue functions as an ectopic pacemaker; therefore, we hypothesized that hPSC-CMs engineered with a dominant negative form of the pacemaker ion channel HCN4 (dnHCN4) would exhibit reduced automaticity and arrhythmogenic risk following transplantation.MethodsWe used CRISPR/Cas9-mediated gene-editing to create transgenic dnHCN4 hPSC-CMs, and their electrophysiological behavior was evaluated in vitro by patch-clamp recordings and optical mapping. Next, we transplanted WT and homozygous dnHCN4 hPSC-CMs in a pig MI model and compared post-transplantation outcomes including the incidence of spontaneous arrhythmias and graft structure by immunohistochemistry.ResultsIn vitro dnHCN4 hPSC-CMs exhibited significantly reduced automaticity and pacemaker funny current (If) density relative to wildtype (WT) cardiomyocytes. Following transplantation with either dnHCN4 or WT hPSC-CMs, all recipient hearts showed transmural infarct scar that was partially remuscularized by scattered islands of human myocardium. However, in contrast to our hypothesis, both dnHCN4 and WT hPSC-CM recipients exhibited frequent episodes of ventricular tachycardia (VT).ConclusionsWhile genetic silencing of the pacemaker ion channel HCN4 suppresses the automaticity of hPSC-CMs in vitro, this intervention is insufficient to reduce VT risk post-transplantation in the pig MI model, implying more complex mechanism(s) are operational in vivo.
- Published
- 2024
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