A2A adenosine receptors and C/EBPβ are crucially required for IL-10 production by macrophages exposed to Escherichia coli
A2A adenosine receptors and C/EBPβ are crucially required for IL-10 production by macrophages exposed to Escherichia coli
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DOI：
10.1182/blood-2007-01-065870
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发表时间：
2007-10-01
期刊：
影响因子：
20.3
通讯作者：
Hasko, Gyorgy
中科院分区：
文献类型：
--
作者：
Csoka, Balazs;Nemeth, Zoltan H.;Hasko, Gyorgy
我们最近表明，内源性腺苷激活 A(2A) 腺苷受体有助于多种微生物脓毒症中白介素 10 (IL-10) 的产生。在这里 14，我们通过将巨噬细胞暴露于大肠杆菌来研究支撑腺苷受体信号传导与感染之间相互作用的分子机制。我们使用受体敲除小鼠证明，A2A 受体激活对于腺苷对大肠杆菌攻击的巨噬细胞产生 IL-10 的刺激作用至关重要，而 A(2B) 受体的作用较小。腺苷对大肠杆菌诱导的 IL-10 产生的刺激作用不需要 Toll 样受体 4 (TLR4) 或 MyD88，但会被 p38 抑制所阻断。使用 shRNA，我们证明 TRAF6 会损害腺苷的增强作用。测量 IL-10 mRNA 丰度并用 IL-10 启动子-荧光素酶构建体转染表明大肠杆菌和腺苷协同激活 IL-10 转录。 IL-10 启动子的连续缺失分析和定点诱变揭示，含有 C/EBP 结合元件的区域负责腺苷对大肠杆菌诱导的 IL-10 启动子活性的刺激作用。腺苷增强了大肠杆菌诱导的核积累和 C/EBP beta 的 DNA 结合。 C/EBP β 缺陷型巨噬细胞无法响应腺苷和大肠杆菌产生 IL-10。我们的结果表明，A(2A) 受体-C/EBP β 轴对于细菌感染后 IL-10 的产生至关重要。
We recently showed that A(2A) adenosine receptor activation by endogenous adenosine contributes to interieukin-10 (IL-10) production in polymicrobial sepsis. Here 14 we investigated the molecular mechanisms underpinning this interaction between adenosine receptor signaling and infection by exposing macrophages to Escherichia coli. We demonstrated using receptor knockout mice that A2A receptor activation is critically required for the stimulatory effect of adenosine on IL-10 production by E coli-challenged macrophages, whereas A(2B) receptors have a minor role. The stimulatory effect of adenosine on E coli-induced IL-10 production did not require toll-like receptor 4 (TLR4) or MyD88, but was blocked by p38 inhibition. Using shRNA we demonstrated that TRAF6 impairs the potentiating effect of adenosine. Measuring IL-10 mRNA abundance and transfection with an IL-10 promoter-luciferase construct indicated that E coli and adenosine synergistically activate IL-10 transcription. Sequential deletion analysis and site-directed mutagenesis of the IL-10 promoter revealed that a region harboring C/EBP binding elements was responsible for the stimulatory effect of adenosine on E coli-induced IL-10 promoter activity. Adenosine augmented E coli-induced nuclear accumulation and DNA binding of C/EBP beta. C/EBP beta-deficient macrophages failed to produce IL-10 in response to adenosine and E coli. Our results suggest that the A(2A) receptor-C/EBP beta axis is critical for IL-10 production after bacterial infection.