Circadian networks in human embryonic stem cell-derived cardiomyocytes

Cell-autonomous circadian oscillations strongly influence tissue physiology and pathophysiology of peripheral organs. Recent in vivo findings in the heart demonstrate that the circadian clock controls oscillatory gene expression programs in the adult myocardium. However, whether in vitro human embryonic stem (ES) cell-derived cardiomyocytes can establish circadian rhythmicity is unknown. Here we report that while undifferentiated human ES cells do not possess a functional clock, oscillatory expression of known core clock genes emerges during directed cardiac differentiation, with robust rhythms in day 30 cardiomyocytes. Our data reveal a stress related oscillatory network of genes that underlies a time-dependent response to doxorubicin, a frequently used anti-cancer drug with cardiotoxic side effects. These results provide a set of oscillatory genes that is relevant to functional cardiac studies and that can be deployed to uncover the potential contribution of the clock to other processes such as cardiac regeneration. Overall design: Human embryonic stem cells (ES cells) were differentiated via a directed differentiation protocol in vitro towards cardiomyocytes for a period of 30 days. Cardiomyocytes were synchronized with dexamethasone and triplicate samples for RNA extraction and sequencing were taken every 4 hours for 48 hours in total. RNA was then extracted using TRIzol, barcoded and amplified following the CEL-Seq protocol.

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Dierickx P, Vermunt MW, Muraro MJ, Creyghton MP, Doevendans PA, van Oudenaarden A, Geijsen N, Van Laake LW