Bikfalvi A, Sauzeau C, Moukadiri H, Maclouf J, Busso N, Bryckaert M, Plouet J, Tobelem G
INSERM U 150, Hopital Lariboisière, Paris, France.
J Cell Physiol. 1991 Oct;149(1):50-9. doi: 10.1002/jcp.1041490108.
Vasculotropin/vascular endothelial cell growth factor (VAS/VEGF) is a newly purified growth factor with a unique specificity for vascular endothelial cells. We have investigated the interactions of VAS/VEGF with human umbilical vein endothelial cells (HUVE cells). 125I-VAS/VEGF was found to HUVE cells in a saturable manner with a half-maximum binding at 2.8 ng/ml. Scatchard analysis did show two classes of high-affinity binding sites. The first class displayed a dissociation constant of 9 pM with 500 sites/cell. The dissociation constant and the number of binding sites of the second binding class were variable for different HUVE cell cultures (KD = 179 +/- 101 pM, 5,850 +/- 2,950 sites/cell). Half-maximal inhibition of 125I-VAS/VEGF occurred with a threefold excess of unlabeled ligand. Basic fibroblast growth factor (bFGF) and heparin did not compete with 125I-VAS/VEGF binding. In contrast, suramin and protamin sulfate completely displaced 125I-VAS/VEGF binding from HUVE cells. VAS/VEGF was shown to be internalized in HUVE cells. Maximum internalization (55% of total cell-associated radioactivity) was observed after 30 min. 125I-VAS/VEGF was completely degraded 2-3 hr after binding. At 3 hr, the trichloroacetic acid (TCA)-soluble radioactivity accumulated in the medium was 60% of the total radioactivity released by HUVE cells. No degradation fragment of 125I-VAS/VEGF was observed. Chloroquine completely inhibited degradation. VAS/VEGF was able to induce angiogenesis in vitro in HUVE cells. However, it did not significantly modulate urokinase-type plasminogen activator (u-PA), tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor (PAI-1), and tissue factor (TF). Prostacyclin production was only stimulated at very high VAS/VEGF concentrations. Taken together, these results indicate that VAS/VEGF might be a potent inducer of neovascularization resulting from a direct interaction with endothelial cells. The angiogenic activity seems to be independent of the plasminogen activator or inhibitor system.
血管促生素/血管内皮细胞生长因子（VAS/VEGF）是一种新纯化的生长因子，对血管内皮细胞具有独特的特异性。我们研究了VAS/VEGF与人脐静脉内皮细胞（HUVE细胞）的相互作用。发现125I-VAS/VEGF以可饱和的方式与HUVE细胞结合，半数最大结合浓度为2.8 ng/ml。Scatchard分析确实显示出两类高亲和力结合位点。第一类的解离常数为9 pM，每个细胞有500个位点。第二类结合位点的解离常数和结合位点数在不同的HUVE细胞培养物中有所不同（KD = 179 +/- 101 pM，5,850 +/- 2,950个位点/细胞）。未标记配体过量三倍时可产生半数最大125I-VAS/VEGF抑制作用。碱性成纤维细胞生长因子（bFGF）和肝素不与125I-VAS/VEGF竞争结合。相反，苏拉明和硫酸鱼精蛋白可完全取代HUVE细胞上的125I-VAS/VEGF结合。VAS/VEGF在HUVE细胞中被内化。30分钟后观察到最大内化（占细胞相关总放射性的55%）。125I-VAS/VEGF在结合后2 - 3小时完全降解。3小时时，培养基中积累的三氯乙酸（TCA）可溶性放射性占HUVE细胞释放的总放射性的60%。未观察到125I-VAS/VEGF的降解片段。氯喹完全抑制降解。VAS/VEGF能够在体外诱导HUVE细胞血管生成。然而，它对尿激酶型纤溶酶原激活剂（u-PA）、组织型纤溶酶原激活剂（t-PA）、纤溶酶原激活剂抑制剂（PAI-1）和组织因子（TF）没有显著调节作用。仅在非常高的VAS/VEGF浓度下刺激前列环素的产生。综上所述，这些结果表明VAS/VEGF可能是一种通过与内皮细胞直接相互作用而产生的强力新生血管诱导剂。血管生成活性似乎独立于纤溶酶原激活剂或抑制剂系统。
