Importance of post-transcriptional regulation of chemokine genes by oxidative stress
Importance of post-transcriptional regulation of chemokine genes by oxidative stress
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DOI：
10.1042/0264-6021:3600321
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发表时间：
2001-12-01
影响因子：
4.1
通讯作者：
Piette, J
中科院分区：
文献类型：
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作者：
Josse, C;Boelaert, JR;Piette, J
转录因子核因子 kappaB (NF-kappaB) 会被各种刺激激活，包括细胞因子、辐射、病毒和氧化应激。在这里，我们表明，虽然 H2O2 诱导会在淋巴细胞 (CEM) 和单核细胞 (U937) 细胞中引起 NF-kappaB 核转位，但它仅导致 U937 细胞中编码白细胞介素 8 (IL-8) 和巨噬细胞炎症蛋白 1a 的 mRNA 种类的产生。在类似条件下，在 CEM 细胞中未观察到这些 mRNA 种类。通过对用 IL-8 启动子报告构建体转染并随后用 H2O2 处理的 U937 细胞进行瞬时转染测定，我们发现 (1) IL-8 启动子驱动的转录在 U937 和 CEM 细胞中均受到刺激，(2) NF-kappaB 位点对于激活至关重要，因为它的缺失消除了 H2O2 的激活。 U937 细胞中 IL-8 mRNA 的产生受到 NF-κB 抑制剂 clasto-lactacystin-β-内酯和 E-64D（L-3-反式-乙氧基-羰基环氧乙烷-2-羰基-L-亮氨酸-3-甲基酰胺）的抑制，但需要从头合成蛋白质。此外，抑制 p38 丝裂原激活蛋白激酶也会降低 H2O2 介导的 IL-8 mRNA 上调。综上所述，这些结果表明 p38 依赖性途径控制的转录后事件在 U937 中 IL-8 mRNA 产生中的重要性。 CEM 细胞中 p38 对 H2O2 的反应活性较低，这可以解释这些细胞中 IL-8 mRNA 缺乏稳定性的原因。
The transcription factor, nuclear factor kappaB (NF-kappaB), is activated by various stimuli including cytokines, radiation, viruses and oxidative stress. Here we show that, although induction with H2O2 gives rise to NF-kappaB nuclear translocation in both lymphocyte (CEM) and monocyte (U937) cells, it leads only to the production of mRNA species encoding interleukin-8 (IL-8) and macrophage inflammatory protein la in U937 cells. Under similar conditions these mRNA species are not observed in CEM cells. With the use of a transient transfection assay of U937 cells transfected with reporter constructs of the IL-8 promoter and subsequently treated with H2O2, we show that (1) IL-8-promoter-driven transcription is stimulated in both U937 and CEM cells and (2) the NF-kappaB site is crucial for activation because its deletion abolishes activation by H2O2. The production of IL-8 mRNA in U937 cells is inhibited by the NF-kappaB inhibitors clasto-lactacystin-beta -lactone and E-64D (L-3-trans-ethoxy-carbonyloxirane-2-carbonyl-L-leucine-3-methyl amide) but requires protein synthesis de novo. Moreover, inhibition of the p38 mitogen-activated protein kinase also decreases the IL-8 mRNA up-regulation mediated by H2O2. Taken together, these results show the importance of post-transcriptional events controlled by a p38-dependent pathway in the production of IL-8 mRNA in U937. The much lower activation of p38 in CEM cells in response to H2O2 could explain the lack of stabilization of IL-8 mRNA in these cells.