Activation of STING-mediated pathway(s) in T cells

 描述(由申请人提供)：这项提案的一个中心科学问题是寻找更多的证据来证明STING在T细胞激活程序中的作用，STING是一种典型的胞浆DNA先天免疫传感器。在研究典型先天环境(巨噬细胞)中的刺痛时，我们通过公共数据库搜索发现淋巴组织中有高水平的刺痛mRNA，这促使我们建立了进一步的实验，在该实验中，我们使用合成的刺激剂DMXAA来观察T细胞的直接激活导致I型干扰素的产生，随后多种干扰素刺激基因(ISG)的显著上调。接下来，我们开展了一些研究，这些研究引导我们发现了具有范式转换潜力的发现。首先，我们检测到DMXAA激活的T细胞产生I型干扰素，同时伴随着数百个ISG的激活。这一激活计划得到了证据的支持，即转录激活子IRF3和TBK1激酶在STING下游被激活。其次，我们确定了T细胞中缺失刺突的非配体效应。由于在人类中广泛存在(20%)的STING功能缺失等位基因与几种疾病有关，因此必须考虑突变等位基因对T细胞的可能影响。我们随后发现，T细胞可以在刺痛激活时产生I型干扰素、肿瘤坏死因子和其他炎症细胞因子，这可能对包括癌症治疗在内的许多治疗具有重要意义：DMXAA最初被测试为癌症药物，因为它具有抗肿瘤和抗血管生成的作用；DMXAA也被报道可刺激先天性和获得性免疫反应，但机制尚不清楚。我们的数据显示，基因消融的刺痛严重减弱了T细胞在TCR结扎后的增殖能力。有趣的是，用DMXAA激活STIN也能抑制TCR诱导的增殖。这两个观察结果将我们引导到一个新的模型，该模型具有STING促进TCR信号，可能通过与下游成分之一的相互作用，但在识别DMXAA后发生移位远离TCR。因此，DMXAA成为调整T细胞中TCR激活的工具。尽管这需要进一步的支持，但这一假说的价值是非常新颖的，因为它将改变我们对T细胞的认知方式。我们设计了实验，这可能为这一假说提供支持。在实验环境中，可以通过使用体外慢病毒或艾滋病毒感染来获得进一步的证据。

 DESCRIPTION (provided by applicant): A central scientific question of this proposal's is finding additional evidence for the role of STING, a typical innate immune sensor of cytosolic DNA, in activation program in T cells. While studying STING in typical innate environment (macrophages), we identified via search of public database high levels of STING mRNA in lymphoid tissues, which prompted us to set up further experiments, in which we used the synthetic STING- agonist DMXAA to observe direct activation of T cells resulting in production of type I IFN followed by significant upregulation of multiple interferon stimulated genes (ISG). We next set up studies that led us to discoveries with paradigm-shifting potential. First, we detected production of type I interferon by DMXAA-activated T cells which is accompanied by activation of hundreds of ISGs. This activation program is supported by evidence showing that transcriptional activator IRF3 and TBK1 kinase is activated downstream of STING. Second, we identify ligand-independent effects of the loss of STING in T cells. Because of widespread (20%) of loss-of-function allele of STING is linked to several pathologies in humans, possible effect of the mutant allele on T cells has to be considered. Our subsequent discovery that T cells can produce type I IFNs, TNF, and other inflammatory cytokines in response to STING activation may have important implications for many therapies, including cancer treatments: DMXAA was initially tested as a cancer drug because of its anti-tumor and anti-vascularization effects; DMXAA was also reported to stimulate both innate and adaptive immune responses but the mechanism was unknown. Our data show that genetic ablation of STING severely attenuates the ability of T cells to proliferate upon TCR-ligation. Interestingly, activation of STING with DMXAA also inhibits TCR-induced proliferation. These two observations lead us to a new model that has STING promote TCR signaling, possibly via interaction with one of the downstream components, but undergoing translocation away from TCR following recognition of DMXAA. Thus DMXAA becomes a tool for tweaking TCR-activation in T cells. Although this has to be further supported, the value of this hypothesis is highly novel because it will change the way we perceive T cells. We have designed experiments, which may provide support for this hypothesis. In experimental settings, further evidence could be obtained by using in vitro lentiviral or HIV infection.