Differential regulation of ARE-mediated TNFα and IL-1β mRNA stability by lipopolysaccharide in RAW264.7 cells
Differential regulation of ARE-mediated TNFα and IL-1β mRNA stability by lipopolysaccharide in RAW264.7 cells
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DOI：
10.1016/j.bbrc.2006.05.093
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发表时间：
2006-07-21
影响因子：
3.1
通讯作者：
Chang, Ching-Jin
中科院分区：
文献类型：
--
作者：
Chen, Yu-Ling;Huang, Ya-Lin;Chang, Ching-Jin
信使RNA降解是真核细胞调节基因表达并影响细胞生长和分化的机制。许多原癌基因、细胞因子和生长因子 RNA 在 3' 非翻译区含有富含 AU 的元件 (ARE)，这使得它们能够成为快速降解的目标。为了研究 ARE 介导的 RNA 稳定性的机制，我们证明了 TNF α 和 IL-1 β mRNA 在 LPS 刺激的巨噬细胞中的表达和调节。 TNF α mRNA 被 LPS 快速诱导，并在诱导 2 小时后显示出较短的半衰期，而 IL-1 β mRNA 则被缓慢诱导并具有较长的半衰期。电泳迁移率变动分析表明，LPS 诱导的不稳定因子 tristetraprolin (TTP) 能够以比 IL-1 beta ARE 更高的亲和力与 TNF α ARE 结合。 HuR 经鉴定可与 TNF α ARE 相互作用，发挥 RNA 稳定活性。 LPS刺激时p38 MAPK通路可激活TTP的表达和磷酸化。此外，TTP和p38通路中激酶的异位表达以及随后的生化检测表明p38通路的激活导致TTP磷酸化及其RNA结合活性降低。含有 ARE 的报告基因测定表明，p38 信号可以逆转 TTP 对 IL-1 beta ARE 的抑制活性，但不能逆转 TNF α ARE 的抑制活性。目前的结果表明，来自 TNF α 和 IL-1 β 的 ARE 的异质性可以反映不同的 ARE 结合蛋白来调节其 RNA 表达。 (c) 2006 Elsevier Inc. 保留所有权利。
Messenger RNA degradation is a mechanism by which eukaryotic cells regulate gene expression and influence cell growth and differentiation. Many protooncogene, cytokine, and growth factor RNAs contain AU-rich element (AREs) in the 3' untranslated regions which enable them to be targeted for rapid degradation. To investigate the mechanism of ARE-mediated RNA stability, we demonstrate the expression and regulation of TNF alpha and IL-1 beta mRNAs in LPS-stimulated macrophages. TNF alpha mRNA was rapidly induced by LPS and showed short half-life at 2-h induction, whereas IL-1 beta mRNA was induced slowly and had longer half-life. Electrophoretic mobility shift assays showed that the LPS-induced destabilization factor tristetraprolin (TTP) could bind to TNF alpha ARE with higher affinity than to IL-1 beta ARE. HuR was identified to interact with TNF alpha ARE to exert RNA stabilization activity. The expression and phosphorylation of TTP could be activated by p38 MAPK pathway during LPS stimulation. Moreover, ectopic expression with TTP and kinases in p38 pathway followed by biochemical assays showed that the activation of p38 pathway resulted in the phosphorylation of TTP and a decrease in its RNA-binding activity. The ARE-containing reporter assay presented that the p38 signal could reverse the inhibitory activity of TTP on IL-1 beta ARE but not on TNF alpha ARE. The present results indicate that the heterogeneity of AREs from TNF alpha and IL-1 beta could reflect distinct ARE-binding proteins to modulate their RNA expression. (c) 2006 Elsevier Inc. All rights reserved.