Yamagishi Sho-Ichi, Nakamura Kazuo, Ueda Seiji, Kato Seiya, Imaizumi Tsutomu
Department of Internal Medicine III, Kurume University School of Medicine, 67 Asahi-machi, Kurume, 830-0011, Japan.
Cell Tissue Res. 2005 Jun;320(3):437-45. doi: 10.1007/s00441-005-1094-8. Epub 2005 Apr 22.
Angiotensin II (Ang II), the dominant effector of the renin-angiotensin system, regulates numerous inflammatory-proliferative responses in vascular wall cells and is thus involved in atherosclerosis. We have previously shown that pigment epithelium-derived factor (PEDF) inhibits advanced glycation end-product-induced pericyte apoptosis, thereby exerting beneficial effects on diabetic retinopathy. However, a role for PEDF in vascular inflammation and atherosclerosis remains to be elucidated. In this study, we have examined whether PEDF inhibits the Ang-II-induced endothelial cell (EC) activation in vitro and the way that it might achieve this effect. Ang II significantly induced redox-sensitive transcriptional factor NF-kappaB activation and subsequent monocyte chemoattractant protein-1 expression in human umbilical vein ECs (HUVEC), both of which were completely inhibited by PEDF or the anti-oxidant N-acetylcysteine. PEDF or diphenylene iodonium, an inhibitor of NADPH oxidase, inhibited Ang-II-induced intracellular reactive oxygen species (ROS) generation in HUVEC. Furthermore, PEDF inhibited Ang-II-induced up-regulation of mRNA levels of p22phox, Nox4, and gp91phox/Nox2, which are membrane components of NADPH oxidase, and its enzymatic activity in HUVEC. Antisense, but not sense, DNAs against p22phox, Nox4, or gp91phox/Nox2 were found significantly to inhibit Ang-II-induced ROS generation in HUVEC. These results demonstrate that PEDF inhibits Ang-II-induced EC activation by suppressing NADPH-oxidase-mediated ROS generation and that PEDF may play a protective role in the development and progression of atherosclerosis.
血管紧张素II（Ang II）是肾素-血管紧张素系统的主要效应物，可调节血管壁细胞中的多种炎症增殖反应，因此参与动脉粥样硬化的发生发展。我们之前已经表明，色素上皮衍生因子（PEDF）可抑制晚期糖基化终产物诱导的周细胞凋亡，从而对糖尿病视网膜病变产生有益作用。然而，PEDF在血管炎症和动脉粥样硬化中的作用仍有待阐明。在本研究中，我们检测了PEDF是否在体外抑制Ang-II诱导的内皮细胞（EC）活化以及其实现这一效应的方式。Ang II可显著诱导人脐静脉内皮细胞（HUVEC）中对氧化还原敏感的转录因子NF-κB活化及随后的单核细胞趋化蛋白-1表达，而PEDF或抗氧化剂N-乙酰半胱氨酸均可完全抑制这两种反应。PEDF或二亚苯基碘鎓（一种NADPH氧化酶抑制剂）可抑制Ang-II诱导的HUVEC内活性氧（ROS）生成。此外，PEDF可抑制Ang-II诱导的HUVEC中p22phox、Nox4和gp91phox/Nox2（NADPH氧化酶的膜成分）的mRNA水平上调及其酶活性。针对p22phox、Nox4或gp91phox/Nox2的反义DNA（而非正义DNA）可显著抑制Ang-II诱导的HUVEC中ROS生成。这些结果表明，PEDF通过抑制NADPH氧化酶介导的ROS生成来抑制Ang-II诱导的EC活化，且PEDF可能在动脉粥样硬化的发生发展过程中发挥保护作用。
