PLK inhibitors identified by high content phenotypic screening promote maturation of human PSC-derived cardiomyocytes

Human pluripotent stem cells-derived cardiomyocytes (hPSC-CMs) provide an unlimited source of human cardiomyocytes for disease modeling, cell therapies, and other biomedical applications. However, hPSC-CMs remain developmentally immature which limits their suitability in translational applications. High Content Screening (HCS) is a powerful tool for identifying novel molecules and pathways regulating complex biological processes, but no HCS assay for hPSC-CM maturation has yet been reported. PCM1, a centriole satellite protein, is specifically restricted on nuclear envelope in mature cardiomyocytes. We developed a High Content Screen (HCS) based on PCM1 subcellular localization in hPSC-CMs to identify novel molecules promoting cardiomyocyte maturation, which identified 93 from 1693 compounds that enhance maturation of hPSC-CMs, including multiple PLK inhibitors. Volasertib and Centrinone, two PLK inhibitors, can enhance binucleation, and promote metabolic and electrophysiological maturation in hPSC-CMs. Furthermore, PI3K-AKT signaling pathway was found to be suppressed by PLK inhibitors, and VO-Ohpic, a PTEN inhibitor that activates AKT pathway, blunted the effect of PLK inhibitors on hPSC-CM maturation. In summary, our HCS assay found that PLK inhibitors can promote maturation of hPSC-CMs through suppressing AKT signaling pathway.