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Updated: Aug 3, 2025
Viral Transgene Expression in Rodent Hearts and the Assessment of Cardiac Arrhythmia Risk
Published on: July 27, 2022
Gene editing to prevent ventricular arrhythmias associated with cardiomyocyte cell therapy
Silvia Marchiano1, Kenta Nakamura2, Hans Reinecke1
1Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA.
Insights
Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) can treat heart attacks but cause arrhythmias due to immature electrical activity. Genetic engineering to control ion channels prevents these arrhythmias, improving hPSC-CM therapy safety.
Area of Science:
- Cardiology
- Regenerative Medicine
- Electrophysiology
Background:
- Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) show promise for myocardial infarction treatment.
- Engraftment arrhythmias (EAs) caused by hPSC-CMs limit their clinical use.
- EAs are hypothesized to stem from the immature, pacemaker-like activity of hPSC-CMs.
Purpose of the Study:
- To investigate the ion channel mechanisms underlying hPSC-CM automaticity.
- To engineer hPSC-CMs lacking automaticity for safer cardiac transplantation.
- To assess the in vivo engraftment and electrophysiological behavior of engineered hPSC-CMs.
Main Methods:
- Characterized ion channel expression during hPSC-CM maturation.
- Utilized pharmacology and genome editing to identify and modify genes responsible for automaticity.
- Transplanted engineered hPSC-CMs into porcine hearts to evaluate in vivo performance.
Main Results:
- Identified HCN4, CACNA1H, and SLC8A1 as key depolarization-associated genes and KCNJ2 as a hyperpolarization-associated gene.
- Engineered hPSC-CMs lacking automaticity were created by abolishing depolarization genes and overexpressing KCNJ2.
- Transplanted engineered hPSC-CMs engrafted, coupled electromechanically, and did not cause sustained EAs in vivo.
Conclusions:
- The immature electrophysiological profile of hPSC-CMs mechanistically underlies engraftment arrhythmias.
- Targeting hPSC-CM automaticity is a viable strategy to enhance the safety of cell-based cardiac therapies.
- Engineered hPSC-CMs lacking automaticity offer a safer alternative for cardiac remuscularization.
Abstract:
Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) offer a promising cell-based therapy for myocardial infarction. However, the presence of transitory ventricular arrhythmias, termed engraftment arrhythmias (EAs), hampers clinical applications. We hypothesized that EA results from pacemaker-like activity of hPSC-CMs associated with their developmental immaturity. We characterized ion channel expression patterns during maturation of transplanted hPSC-CMs and used pharmacology and genome editing to identify those responsible for automaticity in vitro. Multiple engineered cell lines were then transplanted in vivo into uninjured porcine hearts. Abolishing depolarization-associated genes HCN4, CACNA1H, and SLC8A1, along with overexpressing hyperpolarization-associated KCNJ2, creates hPSC-CMs that lack automaticity but contract when externally stimulated. When transplanted in vivo, these cells engrafted and coupled electromechanically with host cardiomyocytes without causing sustained EAs. This study supports the hypothesis that the immature electrophysiological prolife of hPSC-CMs mechanistically underlies EA. Thus, targeting automaticity should improve the safety profile of hPSC-CMs for cardiac remuscularization.
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