Hand1 and Hand2 are transcriptional factors, and knockout mice of these genes show left and right ventricular hypoplasia, respectively. However, their function and expression in human cardiogenesis are not well studied. To delineate their expressions and assess their functions in human cardiomyocytes (CMs) in vitro, we established two triple-reporter human induced pluripotent stem cell lines that express HAND1^mCherry, HAND2^EGFP and either MYH6-driven iRFP670 or tagBFP constitutively and investigated their expression dynamics during cardiac differentiation. On day 5 of the differentiation, HAND1 expression marked cardiac progenitor cells. We profiled the CM subpopulations on day 20 with RNA sequencing and found that mCherry+ CMs showed higher proliferative ability than mCherry− CMs and identified a gene network of LEF1, HAND1, and HAND2 to regulate proliferation in CMs. Finally, we identified CD105 as a surface marker of highly proliferative CMs.

Hand1和Hand2是转录因子，这些基因的敲除小鼠分别显示左心室和右心室发育不全。然而，它们在人类心脏发生中的功能和表达还没有得到很好的研究。为了在体外描述它们的表达并评估它们在人心肌细胞 (CMs)中的功能，我们建立了两个三重报告基因人类诱导多能干细胞系，它们组成性地表达HAND1 ^mCherry、HAND2 ^EGFP和MYH6驱动的 iRFP670 或 tagBFP，并研究了它们的表达动态在心脏分化过程中。在分化的第 5 天，HAND1表达标记的心脏祖细胞。我们在第 20 天用 RNA 测序分析了 CM 亚群，发现 mCherry+ CM 比 mCherry-CM 表现出更高的增殖能力，并确定了LEF1、HAND1和HAND2的基因网络来调节 CM 的增殖。最后，我们将 CD105 鉴定为高度增殖性 CM 的表面标志物。