High molecular weight kininogen and factor XII binding to endothelial cells and astrocytes
High molecular weight kininogen and factor XII binding to endothelial cells and astrocytes
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DOI：
10.1160/th03-04-0231
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发表时间：
2003-11-01
影响因子：
6.7
通讯作者：
Kaplan, AP
中科院分区：
文献类型：
--
作者：
Fernando, LP;Natesan, S;Kaplan, AP
我们已经定量的结合高分子量激肽原（HK）的人肺和真皮来源的微血管内皮细胞以及星形胶质细胞和比较的结果与人脐静脉内皮细胞（HUVEC）的报告。我们还重新评估了与HUVEC结合的参数，采用悬浮细胞以及附着在培养板上的细胞，并报告了相似的位点数量，每个细胞从6.96 x 10（5）到7.71 x 10（5）不等。目前的研究表明，HK与微血管内皮细胞（Kd = 10.35 nM）相比具有高特异性和亲和力（Kd = 1.86至4.5 nM），但与星形胶质细胞（Kd = 23.73 nM）的亲和力较低。人细胞角蛋白I，尿激酶纤溶酶原激活物受体和gClqR被认为是HK结合蛋白存在于微血管内皮细胞和星形胶质细胞的表面类似于在HUVEC中看到的，如通过抑制抗体结合到每个蛋白质进行评估。肺微血管内皮细胞的HK结合位点数约为HUVEC的一半，而真皮微血管内皮细胞和星形胶质细胞的HK结合位点数仅为HUVEC的8-10%。与微血管内皮细胞结合的亲和力大于HUVEC，与星形胶质细胞结合的亲和力相当小，然而与每种细胞类型的结合都不同程度地涉及gClqR、细胞角蛋白I和u-PAR。我们还证明，第一次，因子XII结合到所有这些细胞类型中的饱和和Zn+2依赖的方式。考虑到因子XII加速细胞表面和接触激活级联的蛋白质之间的相互作用以产生缓激肽，因子XII（和前激肽释放酶-HK复合物）的结合可以作为这些蛋白质局部浓缩以促进它们相互作用的机制。
We have quantitated the binding of high molecular weight kininogen (HK) to human microvascular endothelial cells of lung and dermal origin as well as to astrocytes and compared the results with those reported for human umbilical vein endothelial cells (HUVEC). We also reassessed parameters of binding to HUVEC employing cells in suspension as well as cells attached to the culture plate and report similar numbers of sites varying from 6.96 x 10(5) to 7.71 x 10(5) per cell. The present study shows that HK binds with high specificity and affinity to microvascular endothelial cells (Kd = 1.86 to 4.5 nM) compared to HUVEC (Kd = 10.35 nM) but with lower affinity to astrocytes (Kd = 23.73 nM). Human cytokeratin I, urokinase plasminogen activator receptor and gClqR were found to be HK binding proteins present at the surface of microvascular endothelial cells and astrocytes analogous to that seen in HUVEC, as assessed by inhibition of binding with antibody to each protein. Lung microvascular endothelial cells had approximately half the number of HK binding sites as HUVEC while dermal micro vascular endothelial cells and astrocytes had only 8-10% of the sites/cell. The affinity of binding to the microvascular endothelial cells was greater than HUVEC, the affinity of binding to astrocytes was considerably less, nevertheless binding to each cell type involves gClqR, cytokeratin I and u-PAR to varying degrees. We also demonstrate, for the first time, that factor XII binds to all of these cell types in a saturable and Zn+2 dependent manner. Given that factor XII accelerates the interactions among cell surfaces and proteins of the contact activation cascade to generate bradykinin, binding of factor XII (and the prekallikrein-HK complex) may serve as a mechanism by which these proteins are concentrated locally to facilitate their interactions.