Nicholls S E, Heyworth C M, Dexter T M, Lord J M, Johnson G D, Whetton A D
Department of Biochemistry and Applied Molecular Biology, UMIST, Manchester, United Kingdom.
J Immunol. 1995 Jul 15;155(2):845-53.
Granulocyte macrophage colony-forming cells (GM-CFC) are bipotential progenitor cells that can proliferate and develop into macrophages in response to macrophage CSF or into neutrophils in response to stem cell factor or granulocyte CSF. These cytokines promoted growth and development in highly enriched GM-CFC. In [3H]thymidine suicide assays, IL-4 was shown to stimulate proliferation of GM-CFC to the same degree as IL-3 and other potent mitogens for GM-CFC. IL-4 also maintained the clonogenic potential of enriched GM-CFC over a 2-day period. However, after several days in the presence of IL-4, the GM-CFC began to die and retained blast cell morphology characteristic of the isolated GM-CFC. When a high concentration of IL-4 was added to GM-CFC with neutrophilic stimuli, the response of these cells was altered because macrophages were formed. This effect was achieved by a 4-h preincubation with IL-4, suggesting that an early signal produced by IL-4 promotes lineage restriction, although IL-4 itself cannot promote development. IL-4, like macrophage CSF, translocates PKC-alpha to the nucleus in GM-CFC, this redistribution of protein kinase C alpha (PKC-alpha) being inhibited by calphostin C (a PKC inhibitor). Calphostin C also blocked IL-4-mediated development of macrophages in stem cell factor- and granulocyte-CSF-treated cells. This is further evidence that PKC-alpha translocation is involved in the commitment of GM-CFC to macrophage development. This data also suggests that agonist-stimulated lineage commitment can be uncoupled from development in normal hematopoietic cells.
粒细胞巨噬细胞集落形成细胞（GM-CFC）是双能祖细胞，可响应巨噬细胞集落刺激因子（CSF）而增殖并发育为巨噬细胞，或响应干细胞因子或粒细胞CSF而发育为中性粒细胞。这些细胞因子促进了高度富集的GM-CFC的生长和发育。在[3H]胸苷自杀试验中，白细胞介素-4（IL-4）刺激GM-CFC增殖的程度与IL-3及其他对GM-CFC有效的促有丝分裂原相同。IL-4还能在2天内维持富集的GM-CFC的克隆形成潜力。然而，在IL-4存在几天后，GM-CFC开始死亡，并保留了分离出的GM-CFC的原始细胞形态特征。当向有嗜中性粒细胞刺激的GM-CFC中添加高浓度的IL-4时，这些细胞的反应发生改变，因为形成了巨噬细胞。这种效应通过与IL-4预孵育4小时实现，这表明IL-4产生的早期信号促进了谱系限制作用，尽管IL-4本身不能促进发育。与巨噬细胞CSF一样，IL-4可使GM-CFC中的蛋白激酶C-α（PKC-α）转位至细胞核，这种蛋白激酶C-α（PKC-α）的重新分布受到钙泊三醇C（一种PKC抑制剂）的抑制。钙泊三醇C还可阻断IL-4介导的干细胞因子和粒细胞CSF处理细胞中巨噬细胞的发育。这进一步证明PKC-α转位参与了GM-CFC向巨噬细胞发育的定向分化。该数据还表明，在正常造血细胞中，激动剂刺激的谱系定向分化可与发育过程解偶联。
