Zhang Baolin, Cao Huiqing, Rao Gadiparthi N
Department of Physiology, University of Tennessee Health Science Center, Memphis, 38163, USA.
J Biol Chem. 2006 Jan 13;281(2):905-14. doi: 10.1074/jbc.M503945200. Epub 2005 Nov 14.
To determine the efficacy of cytochrome P450 2C9 metabolites of arachidonic acid, viz. 5,6-, 8,9-, 11,12-, and 14,15-epoxyeicosatrienoic acids (EETs), in inducing angiogenesis, we have studied their effects on human dermal microvascular endothelial cell (HDMVEC) tube formation and migration. All four EETs stimulated HDMVEC tube formation and migration in a dose-dependent manner. Because 14,15-EET was found to be slightly more efficacious than 5,6-, 8,9-, and 11,12-EETs in stimulating HDMVEC tube formation and migration, we next focused on elucidation of the signaling mechanisms underlying its angiogenic activity. 14,15-EET stimulated Akt and S6K1 phosphorylation in Src- and phosphatidylinositol 3-kinase (PI3K)-dependent manner in HDMVECs. Inhibition of Src and PI3K-Akt-mTOR signaling by both pharmacological and dominant-negative mutant approaches suppressed 14,15-EET-induced HDMVEC tube formation and migration in vitro and Matrigel plug angiogenesis in vivo. In addition, 14,15-EET induced the expression of fibroblast growth factor-2 (FGF-2) in Src- and PI3K-Akt-dependent and mTOR-independent manner in HDMVECs. Neutralizing anti-FGF-2 antibodies completely suppressed 14,15-EET-induced HDMVEC tube formation and migration in vitro and Matrigel plug angiogenesis in vivo. Together, these results show for the first time that Src and PI3K-Akt signaling via targeting in parallel with FGF-2 expression and mTOR-S6K1 activation plays an indispensable role in 14,15-EET-induced angiogenesis.
为了确定花生四烯酸的细胞色素P450 2C9代谢产物,即5,6-、8,9-、11,12-和14,15-环氧二十碳三烯酸(EETs)在诱导血管生成中的功效,我们研究了它们对人真皮微血管内皮细胞(HDMVEC)管形成和迁移的影响。所有四种EETs均以剂量依赖性方式刺激HDMVEC管形成和迁移。由于发现14,15-EET在刺激HDMVEC管形成和迁移方面比5,6-、8,9-和11,12-EETs略有效,我们接下来专注于阐明其血管生成活性背后的信号传导机制。14,15-EET以Src和磷脂酰肌醇3-激酶(PI3K)依赖性方式刺激HDMVEC中的Akt和S6K1磷酸化。通过药理学和显性负性突变方法抑制Src和PI3K-Akt-mTOR信号传导可抑制14,15-EET诱导的HDMVEC体外管形成和迁移以及体内基质胶栓血管生成。此外,14,15-EET以Src和PI3K-Akt依赖性且mTOR非依赖性方式诱导HDMVEC中碱性成纤维细胞生长因子-2(FGF-2)的表达。中和抗FGF-2抗体可完全抑制14,15-EET诱导的HDMVEC体外管形成和迁移以及体内基质胶栓血管生成。总之,这些结果首次表明,通过与FGF-2表达和mTOR-S6K1激活平行靶向的Src和PI3K-Akt信号传导在14,15-EET诱导的血管生成中起不可或缺的作用。