Molecular dissection of angiotensin II-activated human LOX-1 promoter
Molecular dissection of angiotensin II-activated human LOX-1 promoter
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DOI：
10.1161/01.atv.0000209998.73303.b5
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发表时间：
2006-05-01
影响因子：
8.7
通讯作者：
Mehta, JL
中科院分区：
文献类型：
--
作者：
Chen, JW;Liu, Y;Mehta, JL
目的 - LOX-1 是氧化低密度脂蛋白的受体，在动脉粥样硬化中发挥着关键作用。其表达会受到促动脉粥样硬化刺激（如血管紧张素 II (Ang II)）的上调。在本研究中，我们探索了人冠状动脉内皮细胞 (HCAEC) 中 LOX-1 转录启动子响应 Ang II 的激活。方法和结果 - 我们构建了全长和缺失 LOX-1 启动子突变体，并检查了它们在 HCAEC 中响应 Ang II 的激活。 Ang II（1μmol/L，24小时）显着诱导LOX-1启动子活性超过基础水平，并且116-bp片段（在nt-2247和-2131之间）是这种诱导所必需的。在这个116 bp的启动子片段中，存在转录因子NF-kappa B的潜在结合基序。通过EMSA，我们观察到Ang II对NF-kappa B的激活。 NF-kappa B 在 Ang II 诱导的 LOX-1 启动子激活中的关键作用已通过诱变试验得到证实，并通过使用 NF-kappa B 抑制剂咖啡酸苯乙酯或 NF-kappa B p65 siRNA 阻断 NF-kappa B 激活进一步得到证实。 结论 - 这项研究强烈表明 Ang II 通过激活 NF-kappa B 诱导 LOX-1 启动子激活。
Objective - LOX-1, a receptor for oxidized low-density lipoprotein, plays a critical role in atherosclerosis. Its expression is upregulated by pro-atherogenic stimuli, such as angiotensin II (Ang II). In this study, we explored LOX-1 transcriptional promoter activation in response to Ang II in human coronary artery endothelial cells (HCAECs).Methods and Results - We constructed full-length and deletion LOX-1 promoter mutants and examined their activation in response to Ang II in HCAECs. The Ang II ( 1 mu mol/L for 24 hours) markedly induced LOX-1 promoter activity beyond the basal level, and a 116-bp fragment ( between nt - 2247 and - 2131) was necessary for this induction. Within this 116-bp promoter fragment, there is a potential binding motif for transcription factor NF-kappa B. By EMSA, we observed the activation of NF-kappa B by Ang II. The critical role of NF-kappa B in Ang II - induced LOX-1 promoter activation was confirmed by mutagenesis assay, and further confirmed by blocking NF-kappa B activation with the NF-kappa B inhibitor caffeic acid phenethyl ester or NF-kappa B p65 siRNA.Conclusion - This study strongly suggests that Ang II, by activating NF-kappa B, induces LOX-1 promoter activation.