Chemokine production system of human thrombocytes

血小板在炎症和过敏过程中发挥重要作用。活化的血小板能够释放多种炎症介质，即黑素细胞生长刺激活性（GRO），并通过正常T细胞表达和分泌（RANTES）来调节活化。然而，关于人类巨核细胞产生这些趋化因子的机制知之甚少。在无血清液体培养中，血小板生成素（TPO）选择性地刺激cd34阳性脐带血细胞的巨核细胞生长。利用这些培养细胞，我们研究了人类巨核细胞产生细胞因子。两个× 10^5天的巨核细胞分泌超过1,000 pg/mL的白细胞介素(IL)-8。巨核细胞条件培养基具有多形核白细胞的趋化潜能，但加入抗IL-8抗体后，这种潜能被消除，提示分泌出具有生物活性的IL-8。通过纯化的CD41b^+细胞的逆转录聚合酶链反应和CD41b^+细胞内IL-8的检测，提供了巨核细胞中IL-8合成的直接证据。接下来，我们检查了IL-1的影响。在TPO刺激下，CD34 +脐带血细胞产生巨核细胞的发育和分泌功能。与单独使用TPO相比，添加il -1 α对巨核细胞的生成、内膜分裂或表面标志物的表达没有影响。然而，在TPO存在的情况下，IL-1增强了巨核细胞产生IL-8和生长调节癌基因α (GRO)的能力。相比之下，RANTES、血小板因子4 （PF4）和血小板球蛋白（TG）的产生没有增强。流式细胞术分析和逆转录聚合酶链反应分析显示，TPO产生的巨核细胞表达IL-1受体I型（IL-lR I）。此外，添加抗il - 1r I单克隆抗体可显著降低培养巨核细胞TPO + il -1诱导的IL-S分泌，使其降至单独TPO的水平。这些结果表明，巨核细胞产生IL-8和GRO，而不是RANTES， PF4和TG，是在TPO的帮助下通过IL-1R I信号传导增强的。因此，巨核细胞和血小板可能通过趋化因子释放在炎症的发展中发挥重要作用。少

Platelets play an important role in inflammatory and allergic processes. Activated platelets are capable of releasing a number of inflammatory mediators, i.e., melanocyte growth-stimulating activity (GRO), and regulated on activation with normal T cell expressed and secreted (RANTES). However, little is known about the mechanisms whereby human megakaryocytes produce these chemokines.In a serum-free liquid culture, thrombopoietin (TPO) selectively stimulated the growth of megakaryocytic cells from CD34-positive cord blood cells. Using these cultured cells, we investigated cytokine production by human megakaryocytes. Two x 10^5 Day l0-megakaryocytes secreted more than 1,000 pg/mL of interleukin (IL)-8. The megakaryocyte-conditioned medium had the chemotactic potential of polymorphonuclear leukocytes, which was abrogated by the addition of anti-IL-8 antibody, suggesting the secretion of biologically active IL-8. Direct evidence for IL-8 synthesis in megakaryocytes was provided by reverse … More transcription-polymerase chain reaction on purified CD41b^+ cells and by the detection of intracellular LL-8 in CD41b^+ cells.Next, we examined the effects of IL-1. the common mediator of the inflammatory process, on the development and secretory functions of megakaryocytes generated from CD34^+ cord blood cells under stimulation with TPO.The addition of IL-1alpha did not influence the generation, endomitosis or expression of surface markers of megakaryocytes, as compared with TPO alone. However, IL-1 enhanced the ability of megakaryocytes to produce IL-8 and growth regulating oncogene-alpha (GRO) in the presence of TPO.In contrast, the production of RANTES, platelet factor 4 (PF4) and thromboglobulin (TG) were not potentiated. A flow cytometric analysis and a reverse transcription-polymerase chain reaction analysis revealed IL-1 receptor type I (IL-lR I) expression of megakaryocytes generated by TPO.Moreover, the addition of an anti-IL- 1 R I monoclonal antibody significantly decreased the TPO + IL-1-induced secretion of IL-S by the cultured megakaryocytes, to the level obtained by TPO alone. These results suggest that the production of IL-8 and GRO, but not RANTES, PF4 and TG, by megakaryocytes is potentiated by signaling through IL-1R I with the aid of TPO.Thus, megakaryocytes and platelets may play an important role in the development of inflammation via chemokine release. Less