Mechanisms that regulate the cell cycle status of very primitive hematopoietic cells in long-term human marrow cultures. I. Stimulatory role of a variety of mesenchymal cell activators and inhibitory role of TGF-beta.
Mechanisms that regulate the cell cycle status of very primitive hematopoietic cells in long-term human marrow cultures. I. Stimulatory role of a variety of mesenchymal cell activators and inhibitory role of TGF-beta.
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DOI：
10.1182/blood.v75.1.96.bloodjournal75196
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发表时间：
1990
期刊：
影响因子：
20.3
通讯作者：
J. Cashman;A. Eaves;E. Raines;R. Ross;C. Eaves
中科院分区：
文献类型：
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作者：
J. Cashman;A. Eaves;E. Raines;R. Ross;C. Eaves
长期骨髓培养（LTMC）允许原始人类造血祖细胞在没有外源提供的造血生长因子的情况下维持数周的增殖和分化。先前的研究重点是定义该培养系统中存在的各种类型的细胞，并测量其中维持的不同集落形成细胞亚群的循环行为。这些研究表明，源自输入骨髓的间充质基质成分在调节最原始、高增殖潜力的红系和粒细胞集落形成细胞的周转方面发挥着关键作用，这些细胞几乎只存在于 LTMC 的贴壁层中。在这项研究中，我们表明，每周更换培养基后这些原始造血祖细胞重新进入 S 期是由于马血清中尚未确定的成分，而胎牛血清中不存在这种成分。然而，这种效应并不是马血清中存在的因子所独有的。它还可以通过向 LTMC 添加几种明确的生长调节分子来引发，即血小板衍生生长因子 (PDGF)、白介素-1 (IL-1)、转化生长因子 α (TGF-α) 和 IL-2。这些药物都不能在甲基纤维素测定中刺激造血集落形成细胞，尽管它们都对间充质细胞具有已知的作用，包括在某些情况下增加生长因子产生的能力，从而在克隆形成测定中刺激原始高增殖潜力造血祖细胞。有趣的是，向LTMC添加内毒素后并没有获得刺激作用。 TGF-β 是一种直接作用的负调节因子，如果与新培养基或 IL-1 同时添加到 LTMC 中，它会选择性地作用于原始造血祖细胞，从而阻断其刺激活性。这些结果提出了一个模型，其中通过对间充质元件的影响对正向和负向调节因子进行间接、局部调节，决定了通常在体内保持静止状态的非常原始造血细胞的相邻群体的周转率。
Long-term marrow cultures (LTMC) allow the proliferation and differentiation of primitive human hematopoietic progenitor cells to be maintained for many weeks in the absence of exogenously provided hematopoietic growth factors. Previous investigations focused on defining various types of cells that are present in this culture system and on measuring the cycling behavior of the different subpopulations of colony-forming cells maintained within it. These studies suggested that mesenchymal stromal elements derived from the input marrow play a key role in regulating the turnover of the most primitive, high-proliferative potential erythroid and granulopoietic colony-forming cells that are found almost exclusively in the adherent layer of LTMC. In this study we show that the re-entry into S-phase of these primitive hematopoietic progenitors that occurs after each weekly medium change is due to an as yet undefined constituent of horse serum, which is absent from fetal calf serum. However, this effect is not unique to the factor present in horse serum. It is also elicited by the addition to LTMC of several well-defined growth regulatory molecules, ie, platelet-derived growth factor (PDGF), interleukin-1 (IL-1), transforming growth factor alpha (TGF-alpha), and IL-2. None of these was able to stimulate hematopoietic colony-forming cells in methylcellulose assays, although all have known actions on mesenchymal cells including, in some cases, the ability to increase production of growth factors that can stimulate primitive high-proliferative potential hematopoietic progenitors in clonogenic assays. Interestingly, a stimulating effect was not obtained after addition of endotoxin to LTMC. TGF-beta, a direct-acting negative regulator that acts selectively on primitive hematopoietic progenitor cells if added to LTMC simultaneously with new medium or IL-1, blocked their stimulating activity. These results suggest a model in which indirect, local modulation of both positive and negative regulatory factors via effects on mesenchymal elements determines the rate of turnover of adjacent populations of very primitive hematopoietic cells that are normally maintained in a quiescent state in vivo.