Lumen Formation Is an Intrinsic Property of Isolated Human Pluripotent Stem Cells

Abstract

We demonstrate that dissociated human pluripotent stem cells (PSCs) are intrinsically programmed to form lumens. PSCs form two-cell cysts with a shared apical domain within 20 hr of plating; these cysts collapse to form monolayers after 5 days. Expression of pluripotency markers is maintained throughout this time. In two-cell cysts, an apical domain, marked by EZRIN and atypical PKCζ, is surrounded by apically targeted organelles (early endosomes and Golgi). Molecularly, actin polymerization, regulated by ARP2/3 and mammalian diaphanous-related formin 1 (MDIA), promotes lumen formation, whereas actin contraction, mediated by MYOSIN-II, inhibits this process. Finally, we show that lumenal shape can be manipulated in bioengineered micro-wells. Since lumen formation is an indispensable step in early mammalian development, this system can provide a powerful model for investigation of this process in a controlled environment. Overall, our data establish that lumenogenesis is a fundamental cell biological property of human PSCs.