MONOCYTE/MACROPHAGE REGULATION OF COAGULATION REACTIONS

单核/巨噬细胞在炎症和动脉粥样硬化中起关键作用 过程，在某些情况下，在血管外组织进行 部位，特征为纤维增生反应和纤维蛋白 证词 由于凝血酶是这些反应的有效效应物， 总的假设是，在单核细胞/巨噬细胞中凝血酶的产生是由细胞内凝血酶的分泌引起的。 巨噬细胞表面提供重要的生物调节效应分子 在这些网站上。 目标是确定结合和动力学 控制导致表达式的分子事件的参数 凝血酶在单核细胞/巨噬细胞表面，并开始阐明 调节促凝血剂表达的细胞机制 表型 我们的成就包括：1）因子VIIa与 单核细胞上表达的整合膜蛋白组织因子 膜表面，表现出不同的底物特异性比因子 VIIa与重组组织因子结合，重组组织因子用定义的 磷脂囊泡，特别是关于不能 细胞结合酶识别因子IXa作为底物; 2）类似 单核细胞，即来自人脑微血管的周细胞，可以激活 并通过外源性途径传播凝血反应（即， 组织因子/因子VIIa复合物，随后是凝血酶原酶 然而，与单核细胞不同， 酶复合物可以响应于激动剂 刺激和3）单核细胞改变因子Va辅因子活性， 膜结合弹性蛋白酶和组织蛋白酶G的表达， 对因子Xa亲和力降低（=3倍）的辅因子分子。 我们目前的计划是：1）完成结构/功能分析 和被弹性蛋白酶和组织蛋白酶切割的因子Va的辅因子活性 G; 2）确定组织对因子IX的激活途径， 在单核细胞上组装的因子/因子VIIa复合物，和3）确定 如果组织因子的组成型表达（如观察到的 在我们的周细胞群体中）调节其辅因子在因子 与单核细胞上诱导的组织因子相比，IX活化 膜表面

Monocytes/macrophages play key roles in inflammatory and atherosclerotic processes, which in several instances proceed at extravascular tissue sites and are characterized by a fibroproliferative response and fibrin deposition. Since thrombin is a potent effector of these responses, the overall hypothesis is that thrombin production at the monocyte/ macrophage surface provides an important bioregulatory effector molecule at these sites. The objectives are to define the binding and kinetic parameters governing the molecular events which result in the expression of thrombin at the monocyte/macrophage surface and begin to elucidate the cellular mechanisms which regulate the expression of a procoagulant phenotype. Our accomplishments included demonstrating that 1) factor VIIa bound to the integral membrane protein tissue factor, expressed on the monocyte membrane surface, exhibits different substrate specificity than factor VIIa bound to recombinant tissue factor relipidated with defined phospholipid vesicles, specifically concerning the inability of the cell-bound enzyme to recognize factor IXa as a substrate; 2) like monocytes, pericytes derived from human brain microvessels, can activate and propagate the coagulant response through the extrinsic pathway (i.e. a tissue factor/factor VIIa complex followed by a prothrombinase complex), however, unlike monocytes the activities of the required enzyme complexes can be differentially regulated in response to agonist stimulation and 3) monocytes alter factor Va cofactor activitiy through the expression of membrane-bound elastase and cathepsin G which produce a cofactor molecule with reduced affinity for factor Xa (=3-fold). Our current plans are: 1) to complete the structure/function analyses and cofactor activities of factor Va cleaved by elastase and cathepsin G; 2) to define the activation pathway of factor IX by the tissue factor/factor VIIa complex assembled on monocytes, and 3) to determine if the constitutive expression of tissue factor (such as that observed in our pericyte population) modulates its cofactor function in factor IX activation as compared to tissue factor induced on the monocyte membrane surface.