Chemokine production system of human thrombocytes

血小板在炎症和过敏过程中起重要作用。活化的血小板能够释放许多炎症介质，即，黑素细胞生长刺激活性（GRO）和调节正常T细胞表达和分泌的活化（RANTES）。在无血清液体培养中，血小板生成素（TPO）选择性地刺激CD 34阳性脐血细胞向巨核细胞分化。使用这些培养的细胞，我们研究了人类巨核细胞的细胞因子产生。2 × 10^5个第10天巨核细胞分泌超过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力，通过加入抗IL-8抗体而消除，表明分泌具有生物活性的IL-8。逆转录病毒为巨核细胞合成IL-8提供了直接证据。 ...更多信息 通过对纯化的CD 41 b ^+细胞进行转录-聚合酶链反应，并检测CD 41 b ^+细胞内LL-8的表达，我们检测了IL-1的作用。IL-1 α是炎症过程的共同介质，IL-1 α对TPO刺激下CD 34 ^+脐血细胞生成巨核细胞的发育和分泌功能有明显影响，但与单独使用TPO相比，IL-1 α对巨核细胞的生成、核内有丝分裂和表面标志物的表达无明显影响。IL-1可增强巨核细胞产生IL-8和生长调节癌基因-α（Growth Regulating Oncogene-alpha，GRO）的能力，但对RANTES、血小板因子4（Platelet Factor 4，PF 4）和血小板球蛋白（Thromboglobulin，TG）的产生无明显影响。流式细胞术和逆转录-聚合酶链反应分析显示TPO诱导的巨核细胞表达IL-1受体I（IL-1 R I），并且加入抗IL- 1 R I单克隆抗体可显著降低TPO + IL-1诱导的巨核细胞分泌IL-S的水平。这些结果表明，巨核细胞产生IL-8和GRO，而不是RANTES，PF 4和TG，是通过IL-1 R I信号转导和TPO的帮助下增强的，因此，巨核细胞和血小板可能通过释放趋化因子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