Platelets synthesize large amounts of active plasminogen activator inhibitor 1
Platelets synthesize large amounts of active plasminogen activator inhibitor 1
复制标题
DOI：
10.1182/blood-2004-04-1439
复制
发表时间：
2004-12-15
期刊：
影响因子：
20.3
通讯作者：
Jern, S
中科院分区：
文献类型：
--
作者：
Brogren, H;Karlsson, L;Jern, S
以往的研究表明，从血小板中释放的纤溶酶原激活物抑制剂1（派-1）传递了富血小板血凝块对血栓溶解的抵抗。然而，血小板中的大多数派-1是无活性的，因此其在凝块稳定中的作用尚不清楚。由于血小板保留了mRNA和合成某些蛋白质的能力，我们研究了血小板是否可以重新合成具有活性构型的派-1。派-1 mRNA定量与实时聚合酶链反应和大量的PAW mRNA检测在所有血小板样本。在24小时内，通过酶联免疫吸附测定法测定的派-1蛋白的量增加了25%（P = .001）。代谢放射性标记与S-35-甲硫氨酸随后免疫沉淀证实了正在进行的派-1的合成，这可以进一步刺激凝血酶和嘌呤霉素抑制。通过在组织型纤溶酶原激活剂（tPA）存在下孵育血小板来研究新形成的派-1的活性。该功能测定表明，大多数新蛋白质处于活性构型，并且可以复合结合tPA。因此，在血小板中存在大量活性派-1的连续产生，这可能是血小板有助于稳定血凝块的机制。(C)2004年，美国血液学会。
Previous studies have suggested that plasminogen activator inhibitor 1 (PAI-1) released from platelets convey resistance of platelet-rich blood clots to thrombolysis. However, the majority of PAI-1 in platelets is inactive and therefore its role in clot stabilization is unclear. Because platelets retain mRNA and capacity for synthesis of some proteins, we investigated if platelets can de novo synthesize PAI-1 with an active configuration. PAI-1 mRNA was quantified with real-time polymerase chain reaction and considerable amounts of PAW mRNA were detected in all platelet samples. Over 24 hours, the amount of PAI-1 protein as determined by an enzyme-linked immunosorbent assay increased by 25% (P = .001). Metabolic radiolabeling with S-35-methionine followed by immunoprecipitation confirmed an ongoing PAI-1 synthesis, which could be further stimulated by thrombin and inhibited by puromycin. The activity of the newly formed PAI-1 was investigated by incubating platelets in the presence of tissue-type plasminogen activator (tPA). This functional assay showed that the majority of the new protein was in an active configuration and could complex-bind tPA. Thus, there is a continuous production of large amounts of active PAI-1 in platelets, which could be a mechanism by which platelets contribute to stabilization of blood clots. (C) 2004 by The American Society of Hematology.