Department of Cell Fate Modulation, Institute of Molecular Embryology and Genetics, Kumamoto University, Japan.
Genes Cells. 2010 Sep 1;15(9):983-94. doi: 10.1111/j.1365-2443.2010.01432.x. Epub 2010 Aug 16.
The discovery of a major hematopoietic stem cell pool in midgestation mouse embryo has defined the placenta as an important hematopoietic anatomical site. In this study, we examined the flow cytometric pattern of mouse placenta cells on embryonic days (E) 10.5 to E15.5, in view of CD45 and c-Kit expression. We also determined which population of these cells shows differentiation potential toward multiple hematopoietic lineages by performing coculture with OP9 stromal cells and colony-forming assay in methylcellulose. Only CD45(+)c-Kit(+) population showed the ability to form hematopoietic colonies including multiple lineages. To distinguish which fraction of placenta cells have the hematopoietic activity, we used GFP transgenic mice in which the fetal part of the placenta is GFP positive and the maternal part is GFP negative. E11.5 and E13.5 CD45(+)c-Kit(+) placental cells that have ability to form hematopoietic colonies are the fetal GFP positive placental cells. E11.5 and E13.5 CD45(+)c-Kit(+) placental cells that have an ability to form hematopoietic colonies mainly reside in Hoechst dye-effluxing side population area (SP). Taken together, in the placenta of mouse embryo, we conclude that SP cells in the CD45(+)c-Kit(+) fetal placental cells have the ability to form hematopoietic colonies.
中胚层期小鼠胚胎中主要造血干细胞池的发现将胎盘定义为重要的造血解剖部位。在这项研究中，我们观察了胚胎期 10.5 天至 15.5 天（E）的小鼠胎盘细胞的流式细胞术模式，考虑到 CD45 和 c-Kit 的表达。我们还通过与 OP9 基质细胞共培养和在甲基纤维素中进行集落形成测定，确定了这些细胞中哪一种具有向多种造血谱系分化的潜力。只有 CD45(+)c-Kit(+)群体显示出形成包括多种谱系的造血集落的能力。为了区分具有造血活性的胎盘细胞的分数，我们使用 GFP 转基因小鼠，其中胎盘的胎儿部分是 GFP 阳性，而母体部分是 GFP 阴性。具有形成造血集落能力的 E11.5 和 E13.5 CD45(+)c-Kit(+)胎盘细胞是胎儿 GFP 阳性胎盘细胞。具有形成造血集落能力的 E11.5 和 E13.5 CD45(+)c-Kit(+)胎盘细胞主要位于 Hoechst 染料外排侧群区（SP）。总之，在小鼠胚胎的胎盘组织中，我们得出结论，CD45(+)c-Kit(+)胎儿胎盘细胞中的 SP 细胞具有形成造血集落的能力。
