Ishibashi T, Miller S L, Burstein S A
Blood. 1987 Jun;69(6):1737-41.
To investigate the potential role of platelets in the inhibition of megakaryocytopoiesis, freeze-thawed extracts of human platelets were added to serumless liquid cultures of murine marrow. When acetylcholinesterase (AchE), a marker of megakaryocytic differentiation in mice, was assayed, a significant inhibition of enzymatic activity was noted in cultures containing the equivalent of greater than 5 X 10(6) solubilized platelets per milliliter. Freeze-thawed extracts of granulocytes had significantly less inhibitory effect than did platelets. Transforming growth factor beta (TGF-beta), a growth factor known to be inhibitory to some cell lineages and to be found at relatively high concentrations in platelets, was then added to liquid marrow cultures. A similar inhibition of AchE activity was detected when cultures were stimulated with mitogen-stimulated conditioned medium. The effect was potent with 50% inhibition of AchE activity observed at 4 pmol TGF-beta/L. To determine if TGF-beta inhibited specifically one aspect of megakaryocytic differentiation, the factor was added to isolated single megakaryocytes in serumless culture induced by interleukin 3 (IL3) to increase in size. The number of megakaryocytes increasing in size in response to IL 3 exposure was reduced from 68% to 20% when both factors were simultaneously added to cultures. Colony assays showed that megakaryocytic and granulocyte-macrophage colony detection was inhibited at picomolar concentrations of the factor. These data suggest that TGF-beta is a potent in vitro inhibitor of the murine megakaryocytic lineage, although its effects are not limited to this lineage.
为了研究血小板在抑制巨核细胞生成中的潜在作用，将人血小板的冻融提取物添加到小鼠骨髓的无血清液体培养物中。当检测小鼠巨核细胞分化标志物乙酰胆碱酯酶（AchE）时，发现在每毫升含有相当于超过5×10⁶个溶解血小板的培养物中，酶活性受到显著抑制。粒细胞的冻融提取物的抑制作用明显小于血小板。然后将转化生长因子β（TGF-β）添加到液体骨髓培养物中，TGF-β是一种已知对某些细胞谱系有抑制作用且在血小板中浓度相对较高的生长因子。当用丝裂原刺激的条件培养基刺激培养物时，检测到AchE活性有类似的抑制作用。该作用很强，在4 pmol TGF-β/L时观察到AchE活性受到50%的抑制。为了确定TGF-β是否特异性抑制巨核细胞分化的一个方面，将该因子添加到由白细胞介素3（IL3）诱导的无血清培养中的分离单个巨核细胞中，以使其增大。当将两种因子同时添加到培养物中时，响应IL3暴露而增大的巨核细胞数量从68%减少到20%。集落测定表明，在皮摩尔浓度的该因子下，巨核细胞集落和粒细胞 - 巨噬细胞集落的检测受到抑制。这些数据表明，TGF-β是小鼠巨核细胞谱系的一种有效的体外抑制剂，尽管其作用并不局限于该谱系。
