Vascular endothelial growth factor-induced endothelial cell proliferation is regulated by interaction between VEGFR-2, SH-PTP1 and eNOS
Vascular endothelial growth factor-induced endothelial cell proliferation is regulated by interaction between VEGFR-2, SH-PTP1 and eNOS
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DOI：
10.1016/j.mvr.2005.10.004
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发表时间：
2006-01-01
影响因子：
3.1
通讯作者：
Boulton, M
中科院分区：
文献类型：
--
作者：
Cai, J;Jiang, WG;Boulton, M
VEGF受体-2在血管生成过程中的内皮细胞增殖中起关键作用。然而，受体活性的调节仍然不完全解释。在此，我们证明VEGF以剂量依赖性方式刺激微血管内皮细胞增殖，VEGF诱导的增殖在5和100 ng/ml时最大，在中等浓度时显著降低（20 ng/ml时> 50%）。中和研究证实，信号传导通过VEGFR-2发生。以类似的方式，ERK/MAPK响应于VEGF刺激而被强烈激活，如其磷酸化所证明的，但在20 ng/ml VEGF下磷酸化降低。免疫印迹分析显示，VEGF并没有引起VEGFR-2表达的剂量依赖性变化，但当细胞暴露于10和20 ng/ml的VEGF时，反而导致VEGFR-2磷酸化减少。VEGFR-2去磷酸化与蛋白酪氨酸磷酸酶、SH-PTP 1和内皮型一氧化氮合酶（eNOS）的增加相关。免疫沉淀和选择性免疫印迹证实了VEGFR-2去磷酸化与SH-PTP 1和eNOS上调之间的关联。用VEGFR-2的反义寡核苷酸转染内皮细胞完全消除VEGF诱导的增殖，而抗SH-PTP 1在10和200 ng/ml VEGF下分别显著增加VEGF诱导的增殖1和5倍。抑制eNOS表达仅在VEGF浓度高于20 ng/ml时才能抑制内皮细胞增殖。综上所述，这些结果表明，VEGF激活VEGFR-2增强SH-PTP 1活性和eNOS表达，这反过来又导致两个不同的事件：一个是SH-PTP 1去磷酸化VEGFR-2和ERK/MAPK，这削弱了VEGF促有丝分裂活性，另一个是eNOS增加一氧化氮的产生，这反过来又通过S-亚硝基化降低SH-PTP 1活性。(c)2005年爱思唯尔公司All rights reserved.
VEGF receptor-2 plays a critical role in endothelial cell proliferation during angiogenesis. However, regulation of receptor activity remains incompletely explained. Here, we demonstrate that VEGF stimulates microvascular endothelial cell proliferation in a dose-dependent manner with VEGF-induced proliferation being greatest at 5 and 100 ng/ml and significantly reduced at intermediate concentrations (> 50% at 20 ng/ml). Neutralization studies confirmed that signaling occurs via VEGFR-2. In a similar fashion, ERK/MAPK is strongly activated in response to VEGF stimulation as demonstrated by its phosphorylation, but with a decrease in phosphoryation at 20 ng/ml VEGF. Immunoblotting analysis revealed that VEGF did not cause a dose-dependent change in expression of VEGFR-2 but instead resulted in reduced phosphorylation of VEGFR-2 when cells were exposed to 10 and 20 ng/ml of VEGE VEGFR-2 dephosphorylation was associated with an increase in the protein tyrosine phosphatase, SH-PTP1, and endothelial nitric oxide synthase (eNOS). Immunoprecipitation and selective immunoblotting confirmed the association between VEGFR-2 dephosphorylation and the upregulation of SH-PTP1 and eNOS. Transfection of endothelial cells with antisense oligonucleotide against VEGFR-2 completely abolished VEGF-induced proliferation, whereas anti SH-PTP1 dramatically increased VEGF-induced proliferation by 1 and 5-fold at 10 and 200 ng/ml VEGF, respectively. Suppression of eNOS expression only abolished endothelial cell proliferation at VEGF concentrations above 20 ng/ml. Taken together, these results indicate that activation of VEGFR-2 by VEGF enhances SH-PTP1 activity and eNOS expression, which in turn lead to two diverse events: one is that SH-PTP1 dephosphorylates VEGFR-2 and ERK/MAPK, which weaken VEGF mitogenic activity, and the other is that eNOS increases nitric oxide production which in turn lowers SH-PTP1 activity via S-nitrosylation. (c) 2005 Elsevier Inc. All rights reserved.