Human platelets synthesize and express functional tissue factor
Human platelets synthesize and express functional tissue factor
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DOI：
10.1182/blood-2006-06-030619
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发表时间：
2007-06-15
期刊：
影响因子：
20.3
通讯作者：
Mezzano, Diego
中科院分区：
文献类型：
--
作者：
Panes, Olga;Matus, Valeria;Mezzano, Diego
血源性组织因子（TF）的来源和意义存在争议。人类血小板中已检测到 TF mRNA、蛋白质和 TF 依赖性促凝血活性 (PCA)，但缺少 TF 合成的直接证据。大多数患者的未刺激的无单核细胞血小板表达 TF mRNA，血小板激活后，所有血小板中的 TF mRNA 均得到增强或诱导。免疫沉淀分析显示未刺激的血小板膜中存在 TF 蛋白（主要分子量 [Mr] 约为 47 kDa，其他条带约为 35 和约 60 kDa），其在活化后也增加。这种增强伴随着 TF 易位到质膜，如免疫荧光共聚焦显微镜和膜蛋白生物素化所证明的。通过 Xa 因子 (FXa) 生成评估的血小板 PCA 在激活后被诱导，并分别被抗 TF 和抗 FVIIa 抑制 48% 和 76%，但不能被内在途径抑制剂抑制。血小板将[35S]-甲硫氨酸掺入TF蛋白中，Mr约为47 kDa、约35 kDa和约60 kDa，激活后更强烈。嘌呤霉素而非放线菌素 D 或 DRB（5,6-二氯-1-β-D-呋喃核糖基苯并咪唑）抑制 TIF 新合成。因此，人类血小板不仅在其膜上组装凝血反应，而且还提供自己的 TIF，以在时间和空间限制的过程中生成凝血酶。这些观察结果简化、统一了当前基于细胞的止血模型，并提供了更连贯的公式。
The source and significance of bloodborne tissue factor (TF) are controversial. TF mRNA, protein, and TF-dependent procoagulant activity (PCA) have been detected in human platelets, but direct evidence of TF synthesis is missing. Nonstimulated monocyte-free platelets from most patients expressed TF mRNA, which was enhanced or induced in all of them after platelet activation. Immunoprecipitation assays revealed TF protein (mainly of a molecular weight [Mr] of approximately 47 kDa, with other bands of approximately 35 and approximately 60 kDa) in nonstimulated platelet membranes, which also increased after activation. This enhancement was concomitant with TF translocation to the plasma membrane, as demonstrated by immunofluorescence-confocal microscopy and biotinylation of membrane proteins. Platelet PCA, assessed by factor Xa (FXa) generation, was induced after activation and was inhibited by 48% and 76% with anti-TF and anti-FVIIa, respectively, but not by intrinsic pathway inhibitors. Platelets incorporated [35S]-methionine into TF proteins with Mr of approximately 47 kDa, approximately 35 kDa, and approximately 60 kDa, more intensely after activation. Puromycin but not actinomycin D or DRB (5,6-dichloro-1 -beta-D-ribofuranosylbenzimidazole)inhibited TIF neosynthesis. Thus, human platelets not only assemble the clotting reactions on their membrane, but also supply their own TIF for thrombin generation in a timely and spatially circumscribed process. These observations simplify, unify, and provide a more coherent formulation of the current cellbased model of hemostasis.