Synergistic up-regulation of vascular endothelial growth factor (VEGF) expression in macrophages by adenosine A2A receptor agonists and endotoxin involves transcriptional regulation via the hypoxia response element in the VEGF promoter
Synergistic up-regulation of vascular endothelial growth factor (VEGF) expression in macrophages by adenosine A2A receptor agonists and endotoxin involves transcriptional regulation via the hypoxia response element in the VEGF promoter
复制标题
DOI：
10.1091/mbc.e06-07-0596
复制
发表时间：
2007-01-01
影响因子：
3.3
通讯作者：
Leibovich, Samuel Joseph
中科院分区：
文献类型：
--
作者：
Ramanathan, Madhuri;Pinhal-Enfield, Grace;Leibovich, Samuel Joseph
巨噬细胞是血管内皮生长因子（VEGF）的重要来源。腺苷A（2A）受体（A(2A)R）激动剂与toll样受体（TLR） 2、4、7和9激动剂协同诱导巨噬细胞VEGF表达。我们在这里使用VEGF启动子-荧光素酶报告基因构建表明，TLR4激动剂大肠杆菌脂多糖（LPS）和A(2A)R激动剂NECA和CGS21680协同增强巨噬细胞中VEGF的转录，并且VEGF启动子中的HRE对这种转录至关重要。我们检测了LPS和/或NECA是否诱导HIF-1 α的表达。lps处理的巨噬细胞中HIF-1 α mRNA水平以nf - κ b依赖的方式升高；NECA以A(2A) r依赖的方式强烈增加这些水平。LPS诱导HIF-1 α启动子-荧光素酶构建体以a (2A) r不依赖的方式表达荧光素酶。进一步的NECA刺激并没有增加HIF-1 α启动子的活性，这表明HIF-1 α mRNA的A(2A) r依赖性的增加是转录后的。LPS/NECA处理也增加了HIF-1 α蛋白和DNA结合水平。从VEGF启动子中删除假定的NF-kappa B结合位点不影响LPS/ neca诱导的VEGF启动子活性，这表明NF-kappa B不直接参与VEGF转录。综上所述，这些数据表明LPS/ neca诱导的VEGF表达涉及HIF-1 α通过HRE对VEGF启动子的转录调节。HIF-1 α受LPS的转录诱导，转录后以A(2A) r依赖的方式上调。
Macrophages are an important source of vascular endothelial growth factor (VEGF). Adenosine A(2A) receptor (A(2A)R) agonists with Toll-like receptor (TLR) 2, 4, 7, and 9 agonists synergistically induce macrophage VEGF expression. We show here using VEGF promoter-luciferase reporter constructs that the TLR4 agonist Escherichia coli lipopolysaccharide (LPS) and the A(2A)R agonists NECA and CGS21680 synergistically augment VEGF transcription in macrophages and that the HRE in the VEGF promoter is essential for this transcription. We examined whether LPS and/or NECA induce HIF-1 alpha expression. HIF-1 alpha mRNA levels were increased in LPS-treated macrophages in an NF-kappa B-dependent manner; NECA strongly increased these levels in an A(2A)R-dependent manner. LPS induced luciferase expression from a HIF-1 alpha promoter-luciferase construct in an A(2A)R-independent manner. Further stimulation with NECA did not increase HIF-1 alpha promoter activity, indicating that the A(2A)R-dependent increase in HIF-1 alpha mRNA is post-transcriptional. LPS/NECA treatment also increased HIF-1 alpha protein and DNA binding levels. Deletion of putative NF-kappa B-binding sites from the VEGF promoter did not affect LPS/NECA-induced VEGF promoter activity, suggesting that NF-kappa B is not directly involved in VEGF transcription. Taken together, these data indicate that LPS/NECA-induced VEGF expression involves transcriptional regulation of the VEGF promoter by HIF-1 alpha through the HRE. HIF-1 alpha is transcriptionally induced by LPS and post-transcriptionally up-regulated in an A(2A)R-dependent manner.