Expression of high affinity receptors for erythropoietin on human bone marrow cells and on the human erythroleukemic cell line, HEL.
Expression of high affinity receptors for erythropoietin on human bone marrow cells and on the human erythroleukemic cell line, HEL.
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促红细胞生成素高亲和力受体在人骨髓细胞和人红白血病细胞系 HEL 上的表达。
DOI：
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发表时间：
1988
影响因子：
2.6
通讯作者：
Michael V. Berridge
中科院分区：
文献类型：
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作者：
J. K. Fraser;F. Lin;Michael V. Berridge
红细胞生成素（Epo）是调节红细胞生成的主要生长因子，目前正在进行治疗贫血的临床试验。尽管这些试验处于先进状态，但对人造血细胞上Epo受体的性质和分布或信号转导的细胞机制知之甚少。在本研究中，125I标记的重组人Epo已被用来证明密度分级的人骨髓细胞和人红白血病细胞系，HEL上的Epo的饱和，高亲和力结合位点的表达。结合是可逆的并且与细胞数量成比例，并且显示HEL细胞在37 ℃下在叠氮化钠存在下以293 pM（范围275 - 300 pM）的亲和力平均每个细胞表达34个受体（范围30 - 35）以阻断受体内化。Epo与人骨髓细胞结合的放射自显影分析表明，特异性结合（测量为总结合和过量未标记Epo存在下结合之间的颗粒计数差异）对原变态细胞最大，并在红系细胞成熟过程中下降至有核红细胞上检测不到的水平。放射自显影也显示显着的Epo结合骨髓巨核细胞，其中包括不到1%的非红细胞。与红系细胞相反，Epo与巨核细胞的结合随着细胞成熟而增加，IV期巨核细胞表现出最高的特异性结合。然而，每表面积的颗粒密度在巨核细胞成熟过程中保持不变，约为原形细胞的25%。
The principal growth factor involved in the regulation of erythropoiesis, erythropoietin (Epo), is currently under clinical trial for the treatment of anemia. Despite the advanced state of these trials, little is known about the nature and distribution of the receptor for Epo on human hemopoietic cells or about the cellular mechanisms of signal transduction. In the present study 125I-labeled recombinant human Epo has been used to demonstrate expression of saturable, high affinity binding sites for Epo on density-fractionated human bone marrow cells and on the human erythroleukemic cell line, HEL. Binding was reversible and proportional to cell number, and HEL cells were shown to express on average 34 receptors per cell (range 30-35) with an affinity of 293 pM (range 275-300 pM) at 37 degrees C in the presence of sodium azide to block receptor internalization. Autoradiographic analysis of Epo binding to human bone marrow cells showed that specific binding, measured as the difference in grain counts between total binding and binding in the presence of excess unlabeled Epo, was greatest to pronormoblasts and declined during erythroid cell maturation to undetectable levels on nucleated red cells. Autoradiography also revealed significant Epo binding to marrow megakaryocytes, which comprise less than 1% of nonerythroid cells. In contrast to erythroid cells, Epo binding to megakaryocytes increased with cell maturation, with stage IV megakaryocytes exhibiting the highest specific binding. Grain density per surface area however, remained constant during megakaryocyte maturation and was approximately 25% that on pronormoblasts.