CD40-dependent activation of phosphatidylinositol 3-kinase/Akt pathway mediates endothelial cell survival and in vitro angiogenesis
CD40-dependent activation of phosphatidylinositol 3-kinase/Akt pathway mediates endothelial cell survival and in vitro angiogenesis
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DOI：
10.1074/jbc.m300711200
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发表时间：
2003-05-16
影响因子：
4.8
通讯作者：
Camussi, G
中科院分区：
文献类型：
--
作者：
Deregibus, MC;Buttiglieri, S;Camussi, G
CD40参与肿瘤和炎症新生血管生成。在这项研究中，我们发现sCD154刺激内皮细胞CD40可诱导人微血管内皮细胞（HMEC）抵抗凋亡和体外血管样形成。由于可溶性CD40-muIg融合蛋白抑制了这些效应，因此确定这些效应是由cd40依赖性信号介导的。此外，HMEC的凋亡与Akt磷酸化的损伤有关，Akt磷酸化可通过sCD154刺激恢复。用两种不相关的磷脂酰肌醇3-激酶（PI3K）药理抑制剂wortmannin和LY294002处理HMEC，可抑制HMEC的抗凋亡作用、体外血管样形成和Akt磷酸化。CD40刺激诱导Akt酶活性的快速增加，而环己亚胺（一种蛋白质合成抑制剂）无法阻止这一过程。刺激内皮细胞CD40诱导的Akt活性增强与CD40与TRAF6、c-Cbl和PI3K的p85亚基的关联暂时相关。负显性Akt的表达通过CD40刺激抑制内源性Akt的激活，尽管观察到CD40与TRAF6、c-Cbl和PI3K的关联是完整的。Akt的缺陷激活不仅取消了CD40刺激的抗凋亡作用，而且取消了CD40刺激的HMEC的增殖反应、增强的运动性和体外血管样管状结构的形成。综上所述，这些结果表明内皮细胞CD40通过激活PI3K/Akt信号通路，调节细胞存活、增殖、迁移和血管样结构的形成，这些都被认为是血管生成的关键步骤。
CD40 has been involved in tumor and inflammatory neoangiogenesis. In this study we determined that stimulation of endothelial CD40 with sCD154 induced resistance to apoptosis and in vitro vessel-like formation by human microvascular endothelial cells (HMEC). These effects were determined to be mediated by CD40-dependent signaling because they were inhibited by a soluble CD40-muIg fusion protein. Moreover, apoptosis of HMEC was associated with an impairment of Akt phosphorylation, which was restored by stimulation with sCD154. The anti-apoptotic effect as well as in vitro vessel-like formation and Akt phosphorylation were inhibited by treatment of HMEC with two unrelated pharmacological inhibitors of phosphatidylinositol 3-kinase (PI3K), wortmannin and LY294002. CD40 stimulation induced a rapid increase in Akt enzymatic activity that was not prevented by cycloheximide, an inhibitor of protein synthesis. The enhanced Akt activity induced by stimulation of endothelial CD40 was temporarily correlated with the association of CD40 with TRAF6, c-Cbl, and the p85 subunit of PI3K. Expression of negative-dominant Akt inhibited the activation of endogenous Akt through CD40 stimulation, despite the observation that association of CD40 with TRAF6, c-Cbl, and PI3K was intact. The defective activation of Akt abrogated not only the anti-apoptotic effect of CD40 stimulation but also the proliferative response, the enhanced motility, and the in vitro formation of vessel-like tubular structures by CD40-stimulated HMEC. In conclusion, these results suggest that endothelial CD40, through activation of the PI3K/Akt signaling pathway, regulates cell survival, proliferation, migration, and vessel-like structure formation, all steps considered critical for angiogenesis.