Vascular endothelial growth factor acts through novel, pregnancy-enhanced receptor signalling pathways to stimulate endothelial nitric oxide synthase activity in uterine artery endothelial cells
Vascular endothelial growth factor acts through novel, pregnancy-enhanced receptor signalling pathways to stimulate endothelial nitric oxide synthase activity in uterine artery endothelial cells
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DOI：
10.1042/bj20081013
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发表时间：
2009-01-15
影响因子：
4.1
通讯作者：
Bird, Ian M.
中科院分区：
文献类型：
--
作者：
Grummer, Mary A.;Sullivan, Jeremy A.;Bird, Ian M.
在妊娠过程中，血管内皮生长因子调节部分血管内皮细胞的血管生成和血管扩张。在本研究中，我们研究了VEGFRs(血管内皮生长因子受体)和相关的信号通路的相对作用，这些信号通路介导了血管内皮生长因子(165)对内皮型一氧化氮合酶(ENOS)激活的影响。尽管在NP(未怀孕)和P(妊娠)绵羊的子宫动脉内皮细胞中VEGFR-1和VEGFR-2的表达水平相同，但与NP-UAEC相比，VEGF(165)在P-UAEC中激活eNOS的水平更高，而不依赖Akt的激活。选择性的VEGFR-I激动剂胎盘生长因子-L与VEGFR-2相比，仅诱导P-UAECs适度激活eNOS，而VEGFR-2激酶抑制剂阻断VEGFR-2刺激的eNOS激活，提示VEGFR-2主要通过VEGFR-2激活eNOS。尽管血管内皮细胞生长因子(165)也能激活ERK(细胞外信号调节激酶)-1/2，但这对eNOS的激活并不是必需的，因为U0126抑制ERK-1/2的磷酸化，而不是eNOS的激活，VEGFR-2激酶抑制剂抑制eNOS的激活，但不抑制ERK-1/2的磷酸化。此外，PIGF不能激活ERK-1/2以及VEGFR-2选择性激动剂VEGFR-E激活ERK-1/2和eNOS的能力再次表明eNOS和ERK-1/2的激活主要通过VEGFR-2发生。缺乏VEGF，刺激Akt的磷酸化与缺乏强劲的Ser(1179)-eNOS的磷酸化是一致的。尽管在Ser(617)和Set(635)观察到血管内皮生长因子(165)刺激的eNOS磷酸化，但妊娠不会显著改变这一反应。我们的研究发现，Wortmannin可以完全抑制eNOS(165)的激活，但不能抑制LY294002，这意味着下游的一种激酶，可能是Wortmannin选择性的PI3K(磷酸肌醇3-激酶)，独立于Akt而作用于VEGFR-2和eNOS之间。
During pregnancy, VEGF (vascular endothelial growth factor) regulates in part endothelial angiogenesis and vasodilation. In the present study we examine the relative roles of VEGFRs (VEGF receptors) and associated signalling pathways mediating the effects of VEGF(165) on eNOS (endothelial nitric oxide synthase) activation. Despite e(equal expression levels of VEGFR-1 and VEGFR-2 in UAECs (Uterine artery endothelial cells) from NP (non-pregnant) and P (pregnant) sheep, VEGF(165) activates eNOS at a greater level in P- compared with NP-UAEC, independently of Akt activation. The selective VEGFR-I agonist PIGF (placental growth factor)-l elicits only a modest activation of eNOS in P-UAECs compared with VEGF(165), whereas tile VEGFR-2 kinase inhibitor-blocks VEGF(165)-stimulated eNOS activation, Suggesting VEGF,,, predominantly activates eNOS via VEGFR-2. Although VEGF(165) also activates ERK (extracellular-signal-regulated kinase)-1/2, this is not necessary for eNOS activation since U0126 blocks ERK-1/2 phosphorylation, but not eNOS activation, and the VEGFR-2 kinase inhibitor inhibits eNOS activation,but not ERK-1/2 phosphorylation. Furthermore, the inability of PIGF to activate ERK-1/2 and the ability of the VEGFR-2 selective agonist VEGF-E to activate ERK-1/2 and eNOS suggests again that both eNOS and ERK-1/2 activation occur predominately via VEGFR-2. The lack of VEGF,,stimulated Akt phosphorylation is consistent with a lack of robust phosphorylation of Ser(1179)-eNOS. Although VEGF(165)-stimulated eNOS phosphorylation is observed at Ser(617) and Set(635), pregnancy does not significantly alter this response. Our finding that VEGF(165) activation of eNOS is completely inhibited by wortmannin but not LY294002 implies a downstream kinase, possibly a wortmannin-selective PI3K (phosphoinositide 3-kinase), is acting between tile VEGFR-2 and eNOS independently of Akt.