Hypoxia-induced paracrine regulation of vascular endothelial growth factor receptor expression
Hypoxia-induced paracrine regulation of vascular endothelial growth factor receptor expression
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DOI：
10.1172/jci118437
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发表时间：
1996-01-15
影响因子：
15.9
通讯作者：
Isner, JM
中科院分区：
文献类型：
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作者：
Brogi, E;Schatteman, G;Isner, JM
血管内皮生长因子（VEGF）/血管通透性因子（VPF）是内皮细胞（EC）特异性的有丝分裂原，在体内刺激血管生成，特别是在缺血区域。缺氧组织细胞表达VEGF/VPF与同一组织中内皮细胞表达其两种受体KDR和flt-1相一致。我们研究了缺氧或缺氧依赖性条件是否在协调这种现象中起作用。将人脐静脉和微血管内皮细胞暴露于直接低氧或低氧条件培养液（CM）4d。对照EC维持在常氧或常氧-CM中。然后评价I-125-VEGF与EC的结合。低氧处理对I-125-VEGF结合无影响。然而，用缺氧-CM处理EC使I-125-VEGF结合增加了三倍，在24小时达到峰值（P < 0.001，方差分析）。Scatchard分析揭示，结合增加是由于KDR受体/细胞增加了13倍，而KDR亲和力没有变化（K-d = 260 +/- 51 pM，常氧-CM对比K-d = 281 +/- 94 pM，缺氧-CM），EC数无变化（35.6 +/- 5.9 x 10（3）EC/cm（2），常氧-CM vs 33.5 +/- 5.5 x 10（3）EC/cm（2），缺氧-CM）。使用缺氧平滑肌细胞的CM获得了类似的结果。KDR的上调并没有阻止除了缺氧-CM的中和抗体对VEGF，肿瘤坏死因子-α，转化生长因子β 1或碱性成纤维细胞生长因子。类似地，向常氧-CM中添加VEGF或乳酸对VEGF结合没有影响。我们的结论是，缺氧启动的机制可以诱导内皮细胞KDR受体上调。正常或肿瘤性的低分化细胞不仅可以产生VEGF/VPF，而且还可以通过旁分泌诱导EC中的VEGF/VPF受体来调节其作用。
Vascular endothelial growth factor (VEGF)/vascular permeability factor (VPF), an endothelial cell (EC)-specific mitogen, stimulates angiogenesis in vivo, particularly in ischemic regions. VEGF/VPF expression by cells of hypoxic tissues coincides with expression of its two receptors, KDR and flt-1, by ECs in the same tissues. We investigated whether hypoxia or hypoxia-dependent conditions operate in coordinating this phenomenon. Human umbilical vein and microvascular ECs were exposed to direct hypoxia or to medium conditioned (CM) by myoblasts maintained in hypoxia for 4 d. Control ECs were maintained in normoxia or normoxia-CM. Binding of I-125-VEGF to ECs was then evaluated. Hypoxic treatment of ECs had no effect on I-125-VEGF binding. However, treatment of ECs with hypoxia-CM produced a threefold increase in I-125-VEGF binding, with peak at 24 h (P < 0.001, ANOVA). Scatchard analysis disclosed that increased binding was due to a 13-fold increase in KDR receptors/cell, with no change in KDR affinity (K-d = 260 +/- 51 pM, normoxia-CM versus K-d = 281 +/- 94 pM, hypoxia-CM) and no change in EC number (35.6 +/- 5.9 x 10(3) ECs/cm(2), normoxia-CM versus 33.5 +/- 5.5 x 10(3) ECs/cm(2), hypoxia-CM). Similar results were obtained using CM from hypoxic smooth muscle cells. KDR upregulation was not prevented by addition to the hypoxia-CM of neutralizing antibodies against VEGF, tumor necrosis factor-alpha, transforming growth factor beta 1 or basic fibroblast growth factor. Similarly, addition of VEGF or lactic acid to the normoxia-CM had no effect on VEGF binding. We conclude that mechanism(s) initiated by hypoxia can induce KDR receptor upregulation in ECs. Hypoxic cells, normal or neoplastic, not only can produce VEGF/VPF, but can also modulate its effects via paracrine induction of VEGF/VPF receptors in ECs.