Tannenbaum S H, Rick M E, Shafer B, Gralnick H R
Clinical Pathology Department, Clinical Center, National Institutes of Health, Bethesda, MD 20892.
J Lab Clin Med. 1989 Mar;113(3):372-8.
Von Willebrand factor (vWf) is an adhesive glycoprotein composed of identical subunits linked by disulfide bonds to form multimers of varying sizes. VWf is found in platelets and plasma, where it functions in the adhesion of platelets to exposed subendothelium. Subendothelial matrix contains vWf, but the multimeric composition of matrix vWf, its binding site in matrix, and the mechanism by which it is delivered to matrix are unknown. Using human umbilical vein endothelial cell (HUVE) cultures, we have partially characterized subendothelial matrix vWf. Matrix from HUVE was solubilized in sodium dodecyl sulfate and electrophoresed on 1.25% agarose gels. The extracted vWf was composed of extremely high molecular weight (HMW) multimers of vWf not normally found in plasma. The vWf content of HUVE supernatant, extract, and matrix was quantitated and characterized by radioimmunoassay, agarose gel electrophoresis, and densitometry. The matrix-bound or -associated vWf represented 4% to 18% of total HUVE vWf. Western blot analysis of matrix vWf after reduction showed a subunit species of 220 kd. Long-term incubation of HUVE with phorbol 12-myristate 13-acetate (PMA), a compound that causes release of HMW vWf from Weibel-Palade bodies in HUVE, resulted in a marked decrease in matrix vWf (0.2% to 1% of the total vWf). The multimeric pattern of the remaining matrix vWf continued to show predominantly HMW multimers.(ABSTRACT TRUNCATED AT 250 WORDS)
血管性血友病因子（vWf）是一种黏附性糖蛋白，由通过二硫键连接的相同亚基组成，形成大小各异的多聚体。vWf存在于血小板和血浆中，其功能是使血小板黏附于暴露的内皮下层。内皮下基质含有vWf，但基质vWf的多聚体组成、其在基质中的结合位点以及输送至基质的机制尚不清楚。利用人脐静脉内皮细胞（HUVE）培养物，我们已对内皮细胞下基质vWf进行了部分特性分析。将来自HUVE的基质溶解于十二烷基硫酸钠中，并在1.25%琼脂糖凝胶上进行电泳。提取的vWf由血浆中通常不存在的极高分子量（HMW）vWf多聚体组成。通过放射免疫测定、琼脂糖凝胶电泳和光密度测定对HUVE上清液、提取物和基质中的vWf含量进行了定量和特性分析。与基质结合或相关的vWf占HUVE总vWf的4%至18%。还原后对基质vWf进行的蛋白质印迹分析显示，亚基种类为220kd。用佛波醇12 - 肉豆蔻酸酯13 - 乙酸酯（PMA）长期孵育HUVE，PMA是一种可导致HUVE中HMW vWf从魏贝尔-帕拉德小体释放的化合物，结果导致基质vWf显著减少（占总vWf的0.2%至1%）。剩余基质vWf的多聚体模式继续主要显示为HMW多聚体。（摘要截短于250字）
