Inhibition of Gαs/cAMP Signaling Decreases TCR-Stimulated IL-2 transcription in CD4(+) T Helper Cells.
Inhibition of Gαs/cAMP Signaling Decreases TCR-Stimulated IL-2 transcription in CD4(+) T Helper Cells.
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DOI：
10.5334/1750-2187-10-2
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发表时间：
2015-07-06
影响因子：
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通讯作者：
Berlot CH
中科院分区：
文献类型：
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作者：
Hynes TR;Yost EA;Yost SM;Hartle CM;Ott BJ;Berlot CH
背景：环磷酸腺苷在调节T细胞活化和功能中的作用一直存在争议。cAMP通常被称为免疫抑制剂，但它也是产生最佳免疫应答所必需的。由于cAMP的作用可能取决于其细胞环境，本研究探讨Gαs和腺苷酸环化酶的激活机制是否影响其对T细胞受体（TCR）刺激的白细胞介素-2（IL-2）mRNA水平的作用。研究方法：比较了阻断Gs偶联受体（GsPCR）介导的Gs活化对TCR刺激的CD 4 + T细胞IL-2 mRNA水平的影响，以及敲低Gαs表达或抑制腺苷酸环化酶活性的影响。比较了敲低Gαs表达对TCR刺激的cAMP积累的影响与阻断GsPCR信号传导的影响。结果如下：ZM-241385是一种GS偶联A2 A腺苷受体（A2 AR）的拮抗剂，可增强原代人CD 4 + T辅助细胞和Jurkat T细胞中TCR刺激的IL-2 mRNA水平。显性负性Gαs构建体Gα sDN 3也增强TCR刺激的IL-2 mRNA水平。与GsPCR拮抗剂类似，Gα sDN 3阻断Gαs和Gβγ的GsPCR依赖性激活。相比之下，Gαs siRNA和腺苷酸环化酶抑制剂2 '，5'-二脱氧腺苷（ddA）降低TCR刺激的IL-2 mRNA水平。Gαs siRNA，而不是Gα sDN 3，减少TCR刺激的cAMP合成。通过ZM-241385增强IL-2 mRNA水平需要至少两天的TCR刺激，并且在TCR刺激三天后添加ddA增强IL-2 mRNA水平。结论：GsPCR对TCR刺激的IL-2 mRNA水平的调节起抑制作用，而Gαs和cAMP则起刺激作用。此外，Gαs的TCR依赖性激活似乎不涉及GsPCR。这些结果表明，Gαs/cAMP活化的背景和T细胞活化和分化的阶段决定了对TCR刺激的IL-2 mRNA水平的影响。
Background: The role of cAMP in regulating T cell activation and function has been controversial. cAMP is generally known as an immunosuppressant, but it is also required for generating optimal immune responses. As the effect of cAMP is likely to depend on its cellular context, the current study investigated whether the mechanism of activation of Gαs and adenylyl cyclase influences their effect on T cell receptor (TCR)-stimulated interleukin-2 (IL-2) mRNA levels. Methods: The effect of blocking Gs-coupled receptor (GsPCR)-mediated Gs activation on TCR-stimulated IL-2 mRNA levels in CD4+ T cells was compared with that of knocking down Gαs expression or inhibiting adenylyl cyclase activity. The effect of knocking down Gαs expression on TCR-stimulated cAMP accumulation was compared with that of blocking GsPCR signaling. Results: ZM-241385, an antagonist to the Gs-coupled A2A adenosine receptor (A2AR), enhanced TCR-stimulated IL-2 mRNA levels in primary human CD4+ T helper cells and in Jurkat T cells. A dominant negative Gαs construct, GαsDN3, also enhanced TCR-stimulated IL-2 mRNA levels. Similar to GsPCR antagonists, GαsDN3 blocked GsPCR-dependent activation of both Gαs and Gβγ. In contrast, Gαs siRNA and 2’,5’-dideoxyadenosine (ddA), an adenylyl cyclase inhibitor, decreased TCR-stimulated IL-2 mRNA levels. Gαs siRNA, but not GαsDN3, decreased TCR-stimulated cAMP synthesis. Potentiation of IL-2 mRNA levels by ZM-241385 required at least two days of TCR stimulation, and addition of ddA after three days of TCR stimulation enhanced IL-2 mRNA levels. Conclusions: GsPCRs play an inhibitory role in the regulation of TCR-stimulated IL-2 mRNA levels whereas Gαs and cAMP can play a stimulatory one. Additionally, TCR-dependent activation of Gαs does not appear to involve GsPCRs. These results suggest that the context of Gαs/cAMP activation and the stage of T cell activation and differentiation determine the effect on TCR-stimulated IL-2 mRNA levels.