Brown Simon A, Bowen Derrick J, Hallett Maurice B, Giddings John C, Collins Peter W
Department of Haematology, University of Wales College of Medicine, Cardiff, UK.
Thromb Haemost. 2002 Jun;87(6):1057-61.
The interaction of FVIIa with surface-bound tissue factor (TF) induces various cellular changes including cytosolic Ca2+ signals. The release of von Willebrand factor (VWF) from endothelial cell stores may be triggered by an elevation in cytosolic free Ca2+, therefore we investigated the effect of rFVIIa on the release of VWF from human umbilical vein endothelial cells (HUVEC). We show here that rFVIIa induces the release of VWF from HUVEC with or without prestimulation with lipopolysaccharide (LPS). The effect of rFVIIa was dose dependent. However, the release of VWF by HUVEC in response to rFVIIa was significantly greater with LPS prestimulation (3.18 times control) than without LPS prestimulation (1.45 times control) (p < 0.001). Cytosolic Ca2+ signals were detectable only after LPS prestimulation of HUVEC and these were small compared to those elicited by thrombin. No effect on rFVIIa induced release of VWF was seen in the presence of hirudin, site inactivated rFVIIa or the protein kinase C (PKC) inhibitor staurosporine. However, a tyrosine kinase inhibitor genistein, inhibited the rFVIIa induced release of VWF. These data show that release of VWF can occur without involvement of the cytosolic Ca2+/ PKC pathway. FVIIa induced VWF release from endothelial cells may have in vivo significance at sites of TF expression.
凝血因子VIIa（FVIIa）与表面结合的组织因子（TF）相互作用会引发各种细胞变化，包括胞质Ca2+信号。胞质游离Ca2+升高可能触发血管性血友病因子（VWF）从内皮细胞储存库中释放，因此我们研究了重组FVIIa（rFVIIa）对人脐静脉内皮细胞（HUVEC）释放VWF的影响。我们在此表明，无论是否用脂多糖（LPS）进行预刺激，rFVIIa均能诱导HUVEC释放VWF。rFVIIa的作用呈剂量依赖性。然而，与未用LPS预刺激（为对照的1.45倍）相比，用LPS预刺激时HUVEC对rFVIIa反应释放的VWF显著更多（为对照的3.18倍）（p < 0.001）。仅在对HUVEC进行LPS预刺激后才能检测到胞质Ca2+信号，且与凝血酶引发的信号相比这些信号较小。在存在水蛭素、位点失活的rFVIIa或蛋白激酶C（PKC）抑制剂星形孢菌素的情况下，未观察到对rFVIIa诱导的VWF释放有影响。然而，酪氨酸激酶抑制剂染料木黄酮抑制了rFVIIa诱导的VWF释放。这些数据表明，VWF的释放可以在不涉及胞质Ca2+/PKC途径的情况下发生。FVIIa诱导内皮细胞释放VWF可能在TF表达部位具有体内意义。
