Mitjavila M T, Filippi M D, Cohen-Solal K, Le Pesteur F, Vainchenker W, Sainteny F
INSERM U 362, Institut Gustave Roussy, Villejuif, France.
Exp Hematol. 1998 Feb;26(2):124-34.
We investigated the ability of the murine stromal cell line MS-5 to enhance the hematopoietic potential of embryonic stem (ES) cells. The presence of increasing concentrations of MS-5 cells during the differentiation of ES cells into embryoid bodies (EBs) resulted in a positive dose effect on the efficiency of EB development. Moreover, the number of myeloid progenitors derived from EBs at days 6 and 10 of differentiation significantly increased. This increase resulted from an elevation of both the proportions of positive EBs (EBs containing at least one progenitor each) and the progenitor cell content per positive EB. The stimulatory activity of MS-5 cells affected all types of myeloid progenitors except erythroid progenitors, which were depressed. However, the relative numbers of ES-derived granulocyte-macrophage progenitors (colony-forming units granulocyte/macrophage [CFU-GM], -macrophage [CFU-M], and -granulocyte [CFU-G]) and of mixed cell colonies were unchanged. In contrast, the incidence of megakaryocytic progenitors (colony-forming units-megakaryocyte [CFU-MK]) was significantly increased, that of erythroid progenitors (burst-forming units-erythroid [BFU-E]) was concomitantly decreased, and the total numbers of both progenitor types remained constant. Addition of Mpl-ligand (Mpl-L; thrombopoietin) during the growth of EBs was found to mimic the effect of the MS-5 cell line on the output of progenitor cells. No effect of Mpl-L on the efficiency of EB formation was observed. In addition, supplementation of cultures with sufficient soluble Mpl to abrogate Mpl-L activity resulted in the reversion of the quantitative and qualitative effects of MS-5 cells on progenitor cell formation but not on the efficiency of EB formation. Together, these data indicate two major effects and two levels of action of the MS-5 cell line on hematopoietic differentiation of ES cells. First, the cell line acts before hematopoietic determination, promoting the plating efficiency of ES cells via mechanisms that remain to be clarified. Second, at a later stage of differentiation, the MS-5 cells promote hematopoiesis within EBs. Mpl-L appears to be one of the components that confer this latter ability on the MS-5 cell line.
我们研究了小鼠基质细胞系MS-5增强胚胎干细胞（ES细胞）造血潜能的能力。在ES细胞分化为胚状体（EBs）的过程中，MS-5细胞浓度的增加对EB发育效率产生了正向剂量效应。此外，在分化第6天和第10天，源自EBs的髓系祖细胞数量显著增加。这种增加是由于阳性EBs（每个EB至少含有一个祖细胞）的比例以及每个阳性EB中祖细胞含量的提高所致。MS-5细胞的刺激活性影响了除红系祖细胞（其数量减少）之外的所有类型髓系祖细胞。然而，源自ES细胞的粒细胞-巨噬细胞祖细胞（集落形成单位粒细胞/巨噬细胞[CFU-GM]、-巨噬细胞[CFU-M]和-粒细胞[CFU-G]）以及混合细胞集落的相对数量未发生变化。相反，巨核细胞祖细胞（集落形成单位巨核细胞[CFU-MK]）的发生率显著增加，红系祖细胞（爆式红系集落形成单位[BFU-E]）的发生率随之降低，且这两种祖细胞类型的总数保持不变。发现在EB生长过程中添加Mpl配体（Mpl-L；血小板生成素）可模拟MS-5细胞系对祖细胞产出的影响。未观察到Mpl-L对EB形成效率有影响。此外，用足量的可溶性Mpl补充培养物以消除Mpl-L活性，导致MS-5细胞对祖细胞形成的定量和定性影响发生逆转，但对EB形成效率无影响。总之，这些数据表明MS-5细胞系对ES细胞造血分化有两个主要作用和两个作用水平。首先，该细胞系在造血决定之前起作用，通过尚待阐明的机制提高ES细胞的铺板效率。其次，在分化后期，MS-5细胞促进EB内的造血作用。Mpl-L似乎是赋予MS-5细胞系后一种能力的成分之一。
