Basic fibroblast growth factor induces expression of VEGF receptor KDR through a protein kinase C and p44/p42 mitogen-activated protein kinase-dependent pathway
Basic fibroblast growth factor induces expression of VEGF receptor KDR through a protein kinase C and p44/p42 mitogen-activated protein kinase-dependent pathway
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DOI：
10.2337/diabetes.48.5.1145
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发表时间：
1999-05-01
期刊：
影响因子：
7.7
通讯作者：
Aiello, LP
中科院分区：
文献类型：
--
作者：
Hata, Y;Rook, SL;Aiello, LP
血管内皮生长因子（VEGF）和碱性成纤维细胞生长因子（bFGF）是血管生成分子，其组合的有丝分裂活性具有强大的协同作用。然而，这种协同作用背后的分子机制尚不完全清楚。我们检查了 VEGF 和 bFGF 是否影响彼此的表达或改变视网膜毛细血管内皮细胞中 VEGF 受体 KDR 的表达。此外，我们研究了这种反应所涉及的细胞内信号传导机制。 VEGF 诱导的 [H-3] 胸苷摄取与 KDR mRNA 和蛋白浓度密切相关，表明 KDR 表达增加可能是 VEGF 在 bFGF 存在下的协同活性的原因。 bFGF (10 ng/ml) 在 4 小时内诱导 KDR mRNA 表达，并在 24 小时后达到 4.0 倍的增加。 48小时后KDR蛋白表达增加7.5倍。在血清剥夺条件下，VEGF (=50 ng/ml) 不会改变 bFGF、VEGF 或 KDR mRNA 表达。相比之下，在 bFGF 存在的情况下，VEGF 在生长条件下使 KDR mRNA 表达增加 87%，在血清剥夺条件下增加 2.9 倍。蛋白激酶 C (PKC) 激动剂佛波醇肉豆蔻酸酯乙酸酯 (PMA) 在 100 nmol/l 浓度下诱导 KDR mRNA 表达 5.1 倍。 bFGF 在 5 分钟内增加 p44/p42 丝裂原激活蛋白激酶 (MAPK) 磷酸化，在 15 分钟内达到最大值，并在超过 6 小时内保持显着升高。 bFGF 诱导的 MAPK 磷酸化和 KDR mRNA 表达几乎完全被 5 mu mol/l GFX（一种非异构体选择性 PKC 抑制剂）抑制。 MAPK 抑制剂 PD98059 在 100% 抑制 bFGF 诱导的 MAPK 磷酸化的浓度下，使 KDR mRNA 表达降低 72%，表明除 MAPK 之外的途径也可能参与其中。 PKC β 异构体 (LY333531)、蛋白激酶 A (PKA) (H89) 和磷脂酰肌醇 (PI) 3 激酶（渥曼青霉素）的抑制剂没有显着影响。这些数据表明，bFGF 通过 PKC 和 p44/p42 MAPK 依赖性途径刺激 KDR 表达，该途径主要不涉及 PKC、PKA 或 PI-3 激酶的 β 亚型。由于bFGF诱导VEGF表达，并且由于KDR表达增加增强了VEGF作用，导致额外的KDR表达和显着的促有丝分裂活性，这些数据为VEGF和bFGF之间的血管生成协同作用提供了新的机制解释。
Vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) are angiogenic molecules whose combined mitogenic activity is potently synergistic. However, the molecular mechanism underlying this synergy is incompletely understood. We examined whether VEGF and bFGF affect expression of each other or alter expression of the VEGF receptor KDR in retinal capillary endothelial cells. In addition, we investigated the intracellular signaling mechanisms involved in this response. VEGF-induced [H-3]thymidine uptake was tightly correlated with KDR mRNA and protein concentrations, suggesting that increased KDR expression might account for VEGF's synergistic activity in the presence of bFGF. bFGF (10 ng/ml) induced KDR mRNA expression within 4 h and attained a 4.0-fold increase after 24 h. KDR protein expression was increased 7.5-fold after 48 h. VEGF (=50 ng/ml) did not alter bFGF, VEGF, or KDR mRNA expression under serum-deprived conditions. In contrast, VEGF increased KDR mRNA expression 87% under growth conditions and 2.9-fold under serum-deprived conditions in the presence of bFGF. The protein kinase C (PKC) agonist phorbol myristate acetate (PMA) induced KDR mRNA expression 5.1-fold at 100 nmol/l. bFGF increased p44/p42 mitogen-activated protein kinase (MAPK) phosphorylation within 5 min, reaching a maximum within 15 min and remaining significantly elevated for >6 h. bFGF-induced MAPK phosphorylation and KDR mRNA expression were almost completely inhibited by 5 mu mol/l GFX a non-isoform-selective PKC inhibitor. MAPK inhibitor PD98059 reduced KDR mRNA expression 72% at concentrations that inhibited bFGF-induced MAPK phosphorylation 100%, suggesting that pathways in addition to MAPK might also be involved. Inhibitors of the beta isoform of PKC (LY333531), protein kinase A (PKA) (H89), and phosphotidylinositol (PI) 3 kinase (wortmannin) had no significant effect. These data suggest that bFGF stimulates KDR expression through a PKC and p44/p42 MAPK-dependent pathway not primarily involving the beta isoform of PKC, PKA, or PI-3 kinase. Since bFGF induces VEGF expression and since increased KDR expression potentiates VEGF action, resulting in additional KDR expression and marked mitogenic activity, these data provide a novel mechanistic explanation for the angiogenic synergy between VEGF and bFGF.