Sporn L A, Marder V J, Wagner D D
Department of Medicine, University of Rochester School of Medicine and Dentistry, New York 14642.
J Cell Biol. 1989 Apr;108(4):1283-9. doi: 10.1083/jcb.108.4.1283.
von Willebrand factor (vWf) is secreted from endothelial cells by one of two pathways-a constitutive pathway and a regulated pathway originating from the Weibel-Palade bodies. The molecular form of vWf from each of these pathways differs, with the most biologically potent molecules being released from Weibel-Palade bodies (Loesberg, C., M. D. Gonsalves, J. Zandbergen, C. Willems, W. G. Van Aken, H. V. Stel, J. A. Van Mourik, and P. G. DeGroot. 1983. Biochim. Biophys. Acta. 763:160-168; Sporn, L. A., V. J. Marder, and D. D. Wagner. 1987. Cell. 46:185-190). We investigated the polarity of the two secretory pathways using human umbilical vein endothelial cells cultured on polycarbonate membrane filters which allowed sampling of media from both the apical and basolateral compartments. After metabolic labeling of cells, vWf (constitutively secreted during a 10-min period or released during a 10-min treatment with a secretagogue) was purified from the apical and basolateral chambers and subjected to gel analysis. Approximately equal amounts of vWf were constitutively secreted into both chambers, and therefore this secretory pathway appeared to be nonpolarized. On the contrary, an average of 90% of vWf released from Weibel-Palade bodies after treatment with the calcium ionophore A23187 or PMA appeared in the basolateral chamber, indicating that the regulated pathway of secretion is highly polarized. Thrombin, a secretagogue which promotes disruption of the endothelial monolayer, led to release of vWf from cells with no apparent polarity. The presence of microtubule-depolymerizing agents nocodazol and colchicine inhibited the polarized release of vWf. Ammonium chloride treatment did not disrupt the polarity of the regulated secretory pathway, indicating that maintenance of low pH in intracellular compartments was not required for the polarized delivery of preformed Weibel-Palade bodies to the plasma membrane.
血管性血友病因子（vWf）通过两种途径之一从内皮细胞分泌——一种是组成型途径，另一种是源自魏尔-帕拉德小体的调节型途径。来自这些途径中每一种的vWf分子形式不同，其中生物活性最强的分子是从魏尔-帕拉德小体释放的（洛斯伯格，C.，M. D. 贡萨尔维斯，J. 赞德bergen，C. 威廉姆斯，W. G. 范阿肯，H. V. 斯泰尔，J. A. 范穆里克，以及P. G. 德格鲁特。1983年。《生物化学与生物物理学报》。763:160 - 168；斯波恩，L. A.，V. J. 马德，以及D. D. 瓦格纳。1987年。《细胞》。46:185 - 190）。我们使用培养在聚碳酸酯膜滤器上的人脐静脉内皮细胞来研究这两种分泌途径的极性，该滤器允许从顶端和基底外侧隔室采集培养基。在对细胞进行代谢标记后，从顶端和基底外侧腔室中纯化vWf（在10分钟期间组成型分泌或在用促分泌剂处理10分钟期间释放）并进行凝胶分析。大约等量的vWf组成型分泌到两个腔室中，因此这种分泌途径似乎是非极化的。相反，在用钙离子载体A23187或佛波酯处理后从魏尔-帕拉德小体释放的vWf平均有90%出现在基底外侧腔室中，表明调节型分泌途径是高度极化的。凝血酶是一种促进内皮细胞单层破坏的促分泌剂，它导致vWf从细胞中释放，且没有明显的极性。微管解聚剂诺考达唑和秋水仙碱的存在抑制了vWf的极化释放。氯化铵处理并未破坏调节型分泌途径的极性，这表明细胞内区室维持低pH对于将预先形成的魏尔-帕拉德小体极化递送至质膜并非必需。
