Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, CA 90095, USA; David Geffen School of Medicine, Department of Pediatrics, Division of Hematology-Oncology, Los Angeles, CA 90095, USA; Jonsson Comprehensive Cancer Center, University of California Los Angeles, Los Angeles, CA 90095, USA.
Zhejiang University-University of Edinburgh Institute, Zhejiang University School of Medicine, Hangzhou 310058, P. R. China.
Stem Cell Reports. 2020 Mar 10;14(3):433-446. doi: 10.1016/j.stemcr.2020.01.009. Epub 2020 Feb 13.
The development of an in vitro system in which human primordial germ cell-like cells (hPGCLCs) are generated from human pluripotent stem cells (hPSCs) has been invaluable to further our understanding of human primordial germ cell (hPGC) specification. However, the means to evaluate the next fundamental steps in germ cell development have not been well established. In this study we describe a two dimensional extended culture system that promotes proliferation of specified hPGCLCs, without reversion to a pluripotent state. We demonstrate that hPGCLCs in extended culture undergo partial epigenetic reprogramming, mirroring events described in hPGCs in vivo, including a genome-wide reduction in DNA methylation and maintenance of depleted H3K9me2. This extended culture system provides a new approach for expanding the number of hPGCLCs for downstream technologies, including transplantation, molecular screening, or possibly the differentiation of hPGCLCs into gametes by in vitro gametogenesis.
体外系统的发展对于进一步了解人类原始生殖细胞（hPGC）的特化至关重要，该系统可从人类多能干细胞（hPSCs）中产生人类原始生殖细胞样细胞（hPGCLCs）。然而，评估生殖细胞发育的下一个基本步骤的方法尚未得到很好的建立。在这项研究中，我们描述了一种二维扩展培养系统，该系统可促进指定的 hPGCLCs 的增殖，而不会返回到多能状态。我们证明，在扩展培养中的 hPGCLCs 经历部分表观遗传重编程，与体内 hPGCs 中描述的事件相呼应，包括全基因组 DNA 甲基化减少和耗尽的 H3K9me2 的维持。这种扩展培养系统为扩展 hPGCLCs 的数量提供了一种新方法，可用于下游技术，包括移植、分子筛选，或者通过体外配子发生将 hPGCLCs 分化为配子。
