Regulation of the human tumor necrosis factor-α promoter by angiotensin II and lipopolysaccharide in cardiac fibroblasts:: different cis-acting promoter sequences and transcriptional factors
Regulation of the human tumor necrosis factor-α promoter by angiotensin II and lipopolysaccharide in cardiac fibroblasts:: different cis-acting promoter sequences and transcriptional factors
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DOI：
10.1016/s0022-2828(03)00210-4
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发表时间：
2003-10-01
影响因子：
5
通讯作者：
Yokoyama, T
中科院分区：
文献类型：
--
作者：
Sato, H;Watanabe, A;Yokoyama, T
我们最近表明，血管紧张素 (ANG) II 以及机械拉伸可刺激心脏成纤维细胞中肿瘤坏死因子 (TNF) 的产生。目前，我们研究了 ANGII 和脂多糖 (LPS) 上调 TNF-α 基因表达的分子机制。在新生大鼠心脏成纤维细胞中，检测到 TNF-α mRNA 转录增加，因为荧光素酶活性与 TNF-α 启动子的活性相关。该启动子的渐进删除使 LPS 响应区域位于距转录起始位点 -200 至 -120 bp 之间，而 -120 至 -70 bp 之间的序列是 ANGII 诱导表达所需的。接下来，我们检查了 TNF-α 启动子区域中的哪些顺式作用序列对于诱导 TNF-α 转录至关重要。通过使用和不使用特异性抗体的电泳迁移率变动分析进行的竞争分析表明，LPS 增加了 Sp1 和 Sp3 与 Sp1 结合位点的结合，而 Egr-1 并不重要。对于 ANGII，TNF-α 基因诱导需要 ATF-2/c-jun 与 CRE 位点的结合； Ets 和 NF-kappaB 都不是必需的。突变分析证实，对 LPS 的反应依赖于 TNF-α 启动子中的 Sp1 位点，而 CRE 结合位点对于 ANGII 的刺激至关重要。我们得出的结论是，由于心脏成纤维细胞中的 ANGII 或 LPS 通过 TNF-α 启动子中的不同顺式作用序列和不同的转录因子转录激活 TNF-α 基因表达，因此在心力衰竭或心脏肥大和感染性疾病之间诱导 TNF 产生的机制有所不同。 (C) 2003 Elsevier Ltd. 保留所有权利。
We recently showed that angiotensin (ANG) II as well as mechanical stretch stimulated production of tumor necrosis factor (TNF) in cardiac fibroblasts. Presently, we examined the molecular mechanisms by which ANGII and lipopolysaccharide (LPS) upregulate TNF-alpha gene expression. In neonatal rat cardiac fibroblasts, increased transcription of TNF-alpha mRNA was detected as luciferase activity associated with activity of the TNF-alpha promoter. Progressive deletion from this promoter located the LPS-responsive region between -200 and -120 bp from the transcription initiation site, while the sequence between -120 and -70 bp was required for ANGII-induced expression. Next, we examined which cis-acting sequences in the TNF-alpha promoter region were essential for induction of TNF-alpha transcription. Competition analysis by electrophoretic mobility shift assay with and without specific antibodies showed that LPS increased binding of Sp1 and Sp3 to the Sp1-binding site, while Egr-1 was unimportant. With ANGII binding of ATF-2/c-jun to the CRE site was required for TNF-alpha gene induction; neither Ets nor NF-kappaB was essential. Mutation analysis confirmed that response to LPS relied upon the Sp1 site in the TNF-alpha promoter, while the CRE-binding site was essential for stimulation by ANGII. We concluded that since TNF-alpha gene expression is transcriptionally activated by ANGII or LPS in cardiac fibroblasts via different cis-acting sequences in the TNF-alpha promoter and different transcriptional factors, mechanisms inducing TNF production differ between heart failure or cardiac hypertrophy and infectious disease. (C) 2003 Elsevier Ltd. All rights reserved.