Yuan Lei, Nikolova-Krstevski Vesna, Zhan Yumei, Kondo Maiko, Bhasin Manoj, Varghese Laya, Yano Kiichiro, Carman Chris V, Aird William C, Oettgen Peter
Division of Cardiology, Department of Medicine, and the Center for Vascular Biology Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
Circ Res. 2009 May 8;104(9):1049-57. doi: 10.1161/CIRCRESAHA.108.190751. Epub 2009 Apr 9.
ERG (Ets-related gene) is an ETS transcription factor that has recently been shown to regulate a number of endothelial cell (EC)-restricted genes including VE-cadherin, von Willebrand factor, endoglin, and intercellular adhesion molecule-2. Our preliminary data demonstrate that unlike other ETS factors, ERG exhibits a highly EC-restricted pattern of expression in cultured primary cells and several adult mouse tissues including the heart, lung, and brain. In response to inflammatory stimuli, such as tumor necrosis factor-alpha, we observed a marked reduction of ERG expression in ECs. To further define the role of ERG in the regulation of normal EC function, we used RNA interference to knock down ERG. Microarray analysis of RNA derived from ERG small interfering RNA- or tumor necrosis factor-alpha-treated human umbilical vein (HUV)ECs revealed significant overlap (P<0.01) in the genes that are up- or downregulated. Of particular interest to us was a significant change in expression of interleukin (IL)-8 at both protein and RNA levels. Exposure of ECs to tumor necrosis factor-alpha is known to be associated with increased neutrophil attachment. We observed that knockdown of ERG in HUVECs is similarly associated with increased neutrophil attachment compared to control small interfering RNA-treated cells. This enhanced adhesion could be blocked with IL-8 neutralizing or IL-8 receptor blocking antibodies. ERG can inhibit the activity of the IL-8 promoter in a dose dependent manner. Direct binding of ERG to the IL-8 promoter in ECs was confirmed by chromatin immunoprecipitation. In summary, our findings support a role for ERG in promoting antiinflammatory effects in ECs through repression of inflammatory genes such as IL-8.
ERG（Ets相关基因）是一种Ets转录因子，最近研究表明它可调控多种内皮细胞（EC）特异性基因，包括血管内皮钙黏蛋白、血管性血友病因子、内皮糖蛋白和细胞间黏附分子2。我们的初步数据表明，与其他Ets因子不同，ERG在培养的原代细胞以及包括心脏、肺和脑在内的几种成年小鼠组织中呈现出高度的EC特异性表达模式。在受到诸如肿瘤坏死因子-α等炎性刺激后，我们观察到ECs中ERG表达显著降低。为了进一步明确ERG在正常EC功能调控中的作用，我们使用RNA干扰技术敲低ERG。对源自经ERG小干扰RNA或肿瘤坏死因子-α处理的人脐静脉（HUV）ECs的RNA进行微阵列分析，结果显示上调或下调的基因存在显著重叠（P<0.01）。我们特别感兴趣的是白细胞介素（IL）-8在蛋白质和RNA水平的表达均有显著变化。已知ECs暴露于肿瘤坏死因子-α会导致中性粒细胞黏附增加。我们观察到，与对照小干扰RNA处理的细胞相比，敲低HUVECs中的ERG同样会导致中性粒细胞黏附增加。这种增强的黏附作用可被IL-8中和抗体或IL-8受体阻断抗体所阻断。ERG能够以剂量依赖的方式抑制IL-8启动子活性。通过染色质免疫沉淀法证实了ERG在ECs中直接与IL-8启动子结合。总之，我们的研究结果支持ERG通过抑制诸如IL-8等炎性基因在促进ECs抗炎作用中发挥作用。
