Activation of factor IX bound to cultured bovine aortic endothelial cells.
Activation of factor IX bound to cultured bovine aortic endothelial cells.
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与培养的牛主动脉内皮细胞结合的因子 IX 的激活。
DOI：
10.1073/pnas.81.3.913
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发表时间：
1984
影响因子：
11.1
通讯作者：
LaGamma,KS
中科院分区：
文献类型：
--
作者：
Stern,DM;Drillings,M;Kisiel,W;Nawroth,P;Nossel,HL;LaGamma,KS
以前的研究表明，因子IX及其活化形式，因子IXa，结合培养的血管内皮细胞和细胞结合因子IXa保留其促凝血活性。本研究提供的证据表明，因子IX结合培养的牛主动脉内皮细胞可以被激活。通过在NaDodSO 4/聚丙烯酰胺凝胶电泳上发现因子IX分子的裂解以及通过凝血酶处理的因子VIII依赖性因子Xa活性的产生来评估促凝血活性，从而评估因子IX活化。当用佛波醇酯处理内皮细胞并获得组织因子样促凝血活性时，细胞结合因子IX（0.8 μ g/4 × 10（8）细胞/ml）可被因子XIa（5 μ g/ml）或因子VIIa（0.1 μ g/ml）激活，而不需要外源性组织因子。无论因子IX是如何被激活的，细胞结合因子IXa需要凝血酶处理的因子VIII和钙，而不是外源性磷脂，以激活因子X。在进一步的实验中，因子X特异性地和可逆地与内皮细胞结合，依赖于钙，并且具有比因子IX更低的亲和力（在480 nM时的半最大值）。在饱和时，每个细胞结合9.1 × 106个因子X分子。在因子IXa激活因子X后，约50%的形成的因子Xa可被10 mM EDTA从细胞中洗脱，表明因子Xa是细胞相关的。这些观察结果表明，内皮细胞可以结合和促进因子IX和X的激活，在血小板或外源性磷脂的情况下。
Previous studies have shown that factor IX and its activated form, factor IXa, bind to cultured vascular endothelial cells and that cell-bound factor IXa retains its procoagulant activity. The present studies provide evidence that factor IX bound to cultured bovine aortic endothelial cells can be activated. Factor IX activation was assessed by finding cleavage of the factor IX molecule on NaDodSO4/polyacrylamide gel electrophoresis and by the generation of procoagulant activity as assessed by thrombin-treated factor VIII-dependent generation of factor Xa activity. Cell-bound factor IX (0.8 micrograms per 4 X 10(8) cells per ml) could be activated by factor XIa (5 micrograms/ml) or by factor VIIa (0.1 micrograms/ml) without exogenous tissue factor when endothelial cells were treated with phorbol ester and acquired tissue factor-like procoagulant activity. Regardless of how factor IX was activated, the cell-bound factor IXa required thrombin-treated factor VIII and calcium, but not exogenous phospholipid, to activate factor X. In further experiments, factor X bound to endothelial cells specifically and reversibly with a dependence on calcium and with a lower affinity (half-maximal at 480 nM) than factor IX. At saturation, 9.1 X 10(6) factor X molecules were bound per cell. After activation of factor X by factor IXa, approximately 50% of the factor Xa formed could be eluted from the cells by 10 mM EDTA, suggesting that the factor Xa was cell associated. These observations indicate that endothelial cells can bind and promote the activation of factors IX and X in the absence of platelets or exogenous phospholipid.