Langston Will, Chidlow John H, Booth Blake A, Barlow Shayne C, Lefer David J, Patel Rakesh P, Kevil Christopher G
Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center at Shreveport, 1501 Kings Highway, Shreveport, LA 71130, USA.
Free Radic Biol Med. 2007 Mar 1;42(5):720-9. doi: 10.1016/j.freeradbiomed.2006.12.010. Epub 2006 Dec 16.
Previous studies suggest that inflammatory cell adhesion molecules may modulate endothelial cell migration and angiogenesis through unknown mechanisms. Using a combination of in vitro and in vivo approaches, herein we reveal a novel redox-sensitive mechanism by which ICAM-1 modulates endothelial GSH that controls VEGF-A-induced eNOS activity, endothelial chemotaxis, and angiogenesis. In vivo disk angiogenesis assays showed attenuated VEGF-A-mediated angiogenesis in ICAM-1(-/-) mice. Moreover, VEGF-A-dependent chemotaxis, eNOS phosphorylation, and nitric oxide production were impaired in ICAM-1(-/-) mouse aortic endothelial cells (MAEC) compared to WT MAEC. Decreasing intracellular GSH in ICAM-1(-/-) MAEC to levels observed in WT MAEC with 150 microM buthionine sulfoximine restored VEGF-A responses. Conversely, GSH supplementation of WT MAEC with 5 mM glutathione ethyl ester mimicked defects observed in ICAM-1(-/-) cells. Deficient angiogenic responses in ICAM-1(-/-) cells were associated with increased expression of the lipid phosphatase PTEN, consistent with antagonism of signaling pathways leading to eNOS activation. PTEN expression was also sensitive to GSH status, decreasing or increasing in proportion to intracellular GSH concentrations. These data suggest a novel role for ICAM-1 in modulating VEGF-A-induced angiogenesis and eNOS activity through regulation of PTEN expression via modulation of intracellular GSH status.
先前的研究表明，炎症细胞黏附分子可能通过未知机制调节内皮细胞迁移和血管生成。通过体外和体内方法相结合，我们在此揭示了一种新的氧化还原敏感机制，即细胞间黏附分子-1（ICAM-1）通过调节内皮细胞谷胱甘肽（GSH）来控制血管内皮生长因子A（VEGF-A）诱导的内皮型一氧化氮合酶（eNOS）活性、内皮细胞趋化性和血管生成。体内圆盘血管生成试验显示，在ICAM-1基因敲除（-/-）小鼠中，VEGF-A介导的血管生成减弱。此外，与野生型（WT）小鼠主动脉内皮细胞（MAEC）相比，ICAM-1（-/-）小鼠主动脉内皮细胞中VEGF-A依赖性趋化性、eNOS磷酸化和一氧化氮生成均受损。用150微摩尔丁硫氨酸亚砜胺将ICAM-1（-/-）MAEC中的细胞内GSH降低到WT MAEC中观察到的水平，可恢复VEGF-A反应。相反，用5毫摩尔谷胱甘肽乙酯补充WT MAEC中的GSH可模拟ICAM-1（-/-）细胞中观察到的缺陷。ICAM-1（-/-）细胞中血管生成反应不足与脂质磷酸酶PTEN的表达增加有关，这与导致eNOS激活的信号通路的拮抗作用一致。PTEN表达也对GSH状态敏感，与细胞内GSH浓度成比例地降低或增加。这些数据表明，ICAM-1通过调节细胞内GSH状态来调节PTEN表达，从而在调节VEGF-A诱导的血管生成和eNOS活性方面发挥新作用。
