小鼠单倍体滋养层干细胞的建立及遗传学筛选

Placenta is responsible for materials exchange between embryo and mother, abnormity of which is one of the main reason for abortion. Trophoblast stem cells derived from blastocysts maintain unlimited self-renewal and differentiation potentials to extraembryonic lineages in vitro, providing a platform for mechanism research of placenta development. Recently, haploid cells advanced in genetic screening due to having only one set of chromosomes. However, mammalian haploid cell lines restricted to embryonic lineages up to date. Here, we attempt to establish haploid trophoblast stem cells (haTSCs) via embryo implantation and differentiation separately. Further on, we would use haTSCs to perform genetic screening of targets related to placental toxicant. The haTSCs serve as an ideal tool for genetic study of placental development and pharmacy research related to plancenta.

胎盘是胎儿与母体物质交换的主要场所，其发育异常是流产的主要诱因之一。而来自于囊胚的滋养层干细胞，在体外可以无限增殖并具备分化到胎盘谱系各种细胞的潜能，进而为胎盘发育及分子调控提供了一个体外研究平台。近年兴起的单倍体细胞，因其只有一套染色体，而在遗传学筛选方面具有巨大的优势。目前所建立的哺乳类单倍体细胞系全部局限于胚内组织，而作为胎盘谱系的胚外组织尚未有单倍体细胞系报道。本研究拟通过胚胎建系和体外分化两种方式分别在体外尝试建立小鼠单倍体滋养层干细胞，并将其应用于胎盘毒素的药物靶点筛选，不仅为胎盘发育的遗传研究提供一个理想化的工具细胞，还为胎盘类药物的临床前研究提供一个便捷的平台。

本研究利用可诱导过表达转录因子Cdx2的方式，在体外获得小鼠单倍体诱导滋养层干细胞，这类新型的单倍体细胞可在体外自我更新并具备分化到胎盘谱系各种细胞的潜能，为胎盘发育的基因筛查、功能分析及胎盘疾病致病机制等研究提供了理想的体外模型。目前取得的成果如下：1. 利用Tet-on系统过表达Cdx2，在体外获得小鼠单倍体诱导滋养层干细胞；2. 发现影响单倍体细胞二倍化的主要机制是细胞凋亡，抑制凋亡能够极大地减缓单倍体细胞的二倍化速度；3. 通过p53敲除和体内建系获得小鼠单倍体上胚层干细胞。