The ability of human induced pluripotent stem cells (hiPSCs) to differentiate in vitro to each of the three germ layer lineages has made them an important model of early human development and a tool for tissue engineering. However, the factors that disturb the intricate transcriptional choreography of differentiation remain incompletely understood. Here, we uncover a critical time window during which DNA damage significantly reduces the efficiency and fidelity with which hiPSCs differentiate to definitive endoderm. DNA damage prevents the normal reduction of p53 levels as cells pass through the epithelial-to-mesenchymal transition, diverting the transcriptional program toward mesoderm without induction of an apoptotic response. In contrast, TP53-deficient cells differentiate to endoderm with high efficiency after DNA damage, suggesting that p53 enforces a “differentiation checkpoint” in early endoderm differentiation that alters cell fate in response to DNA damage.

人类诱导多能干细胞 (hiPSC)在体外分化为三个胚层谱系的能力使其成为早期人类发育的重要模型和组织工程的工具。然而，干扰复杂的分化转录编排的因素仍然不完全清楚。在这里，我们发现了一个关键的时间窗口，在此期间 DNA 损伤会显着降低 hiPSC 分化为定形内胚层的效率和保真度。当细胞通过上皮-间质转化时，DNA 损伤会阻止 p53 水平的正常降低，从而将转录程序转向中胚层而不诱导细胞凋亡反应。相比之下，TP53- 缺陷细胞在 DNA 损伤后高效分化为内胚层，这表明 p53 在早期内胚层分化中强制执行“分化检查点”，从而改变细胞命运以响应 DNA 损伤。