El-Remessy A B, Al-Shabrawey M, Platt D H, Bartoli M, Behzadian M A, Ghaly N, Tsai N, Motamed K, Caldwell R B
Program in Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia, Athens, USA.
FASEB J. 2007 Aug;21(10):2528-39. doi: 10.1096/fj.06-7854com. Epub 2007 Mar 23.
The modulation of angiogenic signaling by reactive oxygen species (ROS) is an emerging area of interest in cellular and vascular biology research. We provide evidence here that peroxynitrite, the powerful oxidizing and nitrating free radical, is critically involved in transduction of the VEGF signal. We tested the hypothesis that VEGF induces peroxynitrite formation, which causes tyrosine phosphorylation and mediates endothelial cell migration and tube formation, by studies of vascular endothelial cells in vitro and in a model of hypoxia-induced neovascularization in vivo. The specific peroxynitrite decomposition catalyst FeTPPs blocked VEGF-induced phosphorylation of VEGFR2 and c-Src and inhibited endothelial cell migration and tube formation. Furthermore, exogenous peroxynitrite mimicked VEGF activity in causing phosphorylation of VEGFR2 and stimulating endothelial cell growth and tube formation in vitro and new blood vessel growth in vivo. The selective nitration inhibitor epicatechin enhanced VEGF's angiogenic function in activating VEGFR2, c-Src, and promoting endothelial cell growth, migration, and tube formation in vitro and retinal neovascularization in vivo. Decomposing peroxynitrite with FeTPPs or blocking oxidation using the thiol donor NAC blocked VEGF's angiogenic functions in vitro and in vivo. In conclusion, peroxynitrite is critically involved in transducing VEGF's angiogenic signal via nitration-independent and oxidation-mediated tyrosine phosphorylation.
活性氧（ROS）对血管生成信号的调节是细胞和血管生物学研究中一个新兴的热点领域。我们在此提供证据表明，过氧亚硝酸根这种强大的氧化和硝化自由基，在VEGF信号转导中起关键作用。我们通过体外对血管内皮细胞的研究以及体内缺氧诱导新生血管形成的模型，来验证VEGF诱导过氧亚硝酸根形成，进而导致酪氨酸磷酸化并介导内皮细胞迁移和管腔形成这一假说。特异性的过氧亚硝酸根分解催化剂FeTPPs可阻断VEGF诱导的VEGFR2和c-Src磷酸化，并抑制内皮细胞迁移和管腔形成。此外，外源性过氧亚硝酸根在体外可模拟VEGF活性，导致VEGFR2磷酸化，刺激内皮细胞生长和管腔形成，在体内则促进新血管生长。选择性硝化抑制剂表儿茶素可增强VEGF在激活VEGFR2、c-Src方面的血管生成功能，并在体外促进内皮细胞生长、迁移和管腔形成，在体内促进视网膜新生血管形成。用FeTPPs分解过氧亚硝酸根或使用硫醇供体NAC阻断氧化反应，均可在体外和体内阻断VEGF的血管生成功能。总之，过氧亚硝酸根通过非硝化依赖和氧化介导的酪氨酸磷酸化，在转导VEGF血管生成信号中起关键作用。
