Abstract 15821: ArcLight: a Genetically Encoded Fluorescent Voltage Indicator Faithfully Reports Transmembrane Potentials in Embryonic Stem Cell-Derived Cardiomyocytes
Introduction: A major recent advance in disease modeling has been the demonstration that induced pluripotent stem cell (hiPSC) technology can faithfully recapitulate cardiac arrhythmia syndromes. Despite widespread interest, efforts to extend these disease models to include large scale phenotyping have been frustrated by the technical challenges of conventional electrophysiological recordings. Likewise, present optical voltage indicators feature inherent toxicity, poor signal quality, or require advanced imaging equipment. ArcLight, a fluorescent voltage indicator has been developed by fusing a mutated super ecliptic pHluorin to the VSD of the C. intestinalis voltage sensitive phosphatase. Here, we demonstrate the use of ArcLight to faithfully and non-invasively report cardiac action potentials from hESC-derived cardiomoycytes.
Methods: A242-ArcLight constructs were introduced into H7 hESC-derived cardiomyocytes via transient transfection or lentiviral transduction. Isolated cells or differentiating cardiomyocyte clusters were imaged with standard fluorescent microscopy and compared to simultaneous current clamp recordings.
Results: Fluorescent recordings from myocytes recapitulated classical AP morphologies (Figure) which correlated well to simultaneous current clamp recordings, despite a slight time-delay and loss of high-frequency elements. ArcLight readily captured the presence of EADs and APD prolongation upon application dofetilide, and proved capable of discriminating features of hESC-CMs produced from distinct differentiation protocols.
Conclusions: Phenotyping of hESC-CMs with ArcLight provides a robust means to non-invasively characterize and quantify changes in cellular electrophysiology. This facile tool may find use in screening efforts for cardiomyocyte toxicity and/or therapeutics, as well as understand the cues for cardiomyocyte differentiation.
- © 2013 by American Heart Association, Inc.