Crucial role for nuclear factor of activated T cells in T cell receptor-mediated regulation of human interleukin-17
Crucial role for nuclear factor of activated T cells in T cell receptor-mediated regulation of human interleukin-17
复制标题
DOI：
10.1074/jbc.m405764200
复制
发表时间：
2004-12-10
影响因子：
4.8
通讯作者：
Gaffen, SL
中科院分区：
文献类型：
--
作者：
Liu, XKK;Lin, X;Gaffen, SL
炎症细胞因子白细胞介素 (IL)-17 的生物活性已被广泛研究。然而，对于如何控制 IL-17 表达却知之甚少。在这里，我们研究了人类 IL-17 基因转录调控的基础。抗 CD3 交联激活 T 细胞受体 (TCR) 后，外周血单核细胞诱导 IL-17 分泌，并且通过 CD28 的共刺激信号强烈增强 CD3 诱导的 IL-17 产生。为了定义对 IL-17 基因调控重要的顺式作用元件，我们在转录起始位点上游克隆了 1.25 kb 的基因组序列。这种假定的启动子在 CD3 和 CD28 交联后在 Jurkat T 细胞中具有活性，并且其活性被环孢菌素 A 和 MAPK 抑制剂抑制。该启动子在 Hut102 T 细胞中也有活性，我们已证明该细胞能够组成型分泌 IL-17。活化 T 细胞核因子 (NFAT) 或 Ras 的过度表达增强了 IL-17 启动子活性，对特定 TCR 信号通路缺陷的 Jurkat 系的研究为 NFAT 的作用提供了支持证据。为了描绘 IL-17 最小启动子，我们创建了一系列 5' 截短，并鉴定了 -232 和 -159 之间的区域，该区域足以进行诱导型启动子活性。有趣的是，该区域内有两个 NFAT 位点，它们与 Hut102 和 Jurkat 细胞核提取物中的 NFATc1 和 NFATc2 结合。此外，这些位点的突变显着降低了特异性 DNA 结合和报告基因活性，染色质免疫沉淀分析显示体内 NFAT 占据该区域。总之，这些数据表明 NFAT 是 IL-17 启动子中 TCR 信号传导的关键传感器。
The biological activities of the inflammatory cytokine interleukin (IL)-17 have been widely studied. However, comparatively little is known about how IL-17 expression is controlled. Here, we examined the basis for transcriptional regulation of the human IL-17 gene. IL-17 secretion was induced in peripheral blood mononuclear cells following anti-CD3 cross-linking to activate the T cell receptor (TCR), and costimulatory signaling through CD28 strongly enhanced CD3-induced IL-17 production. To define cis-acting elements important for IL-17 gene regulation, we cloned 1.25 kb of genomic sequence upstream of the transcriptional start site. This putative promoter was active in Jurkat T cells following CD3 and CD28 cross-linking, and its activity was inhibited by cyclosporin A and MAPK inhibitors. The promoter was also active in Hut102 T cells, which we have shown to secrete IL-17 constitutively. Overexpression of nuclear factor of activated T cells (NFAT) or Ras enhanced IL-17 promoter activity, and studies in Jurkat lines deficient in specific TCR signaling pathways provided supporting evidence for a role for NFAT. To delineate the IL-17 minimal promoter, we created a series of 5' truncations and identified a region between -232 and -159 that was sufficient for inducible promoter activity. Interestingly, two NFAT sites were located within this region, which bound to NFATc1 and NFATc2 in nuclear extracts from Hut102 and Jurkat cells. Moreover, mutations of these sites dramatically reduced both specific DNA binding and reporter gene activity, and chromatin immunoprecipitation assays showed occupancy of NFAT at this region in vivo. Together, these data show that NFAT is the crucial sensor of TCR signaling in the IL-17 promoter.