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

 描述（由申请人提供）：本提案的一个中心科学问题是寻找STING（细胞溶质DNA的典型先天免疫传感器）在T细胞激活程序中的作用的额外证据。在典型的先天环境（巨噬细胞）中研究STING时，我们通过搜索公共数据库鉴定了淋巴组织中高水平的STING mRNA，这促使我们建立了进一步的实验，其中我们使用合成的STING激动剂DMXAA观察T细胞的直接活化，导致I型IFN的产生，随后是多种干扰素刺激基因（ISG）的显著上调。接下来，我们建立了一些研究，这些研究使我们发现了具有范式转变潜力的发现。首先，我们检测到DMXAA激活的T细胞产生I型干扰素，这伴随着数百个ISG的激活。该激活程序得到证据的支持，该证据显示转录激活因子IRF 3和TBK 1激酶在STING下游被激活。其次，我们确定了T细胞中STING缺失的配体非依赖性效应。由于STING的广泛（20%）功能丧失等位基因与人类中的几种病理学有关，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细胞可以响应STING激活产生I型IFN，TNF和其他炎性细胞因子，这可能对许多治疗方法具有重要意义，包括癌症治疗：DMXAA最初作为癌症药物进行测试，因为它具有抗肿瘤和抗血管化作用; DMXAA也被报道刺激先天性和适应性免疫反应，但机制尚不清楚。我们的数据显示，STING的基因消融严重减弱了T细胞在TCR连接后增殖的能力。有趣的是，用DMXAA激活STING也抑制TCR诱导的增殖。这两个观察结果使我们产生了一种新的模型，该模型具有STING促进TCR信号传导，可能通过与下游组分之一的相互作用，但在识别DMXAA后经历从TCR易位。因此，DMXAA成为调节T细胞中TCR活化的工具。虽然这一点还有待进一步的支持，但这一假设的价值是非常新颖的，因为它将改变我们感知T细胞的方式。我们设计了实验，这可能会为这一假设提供支持。在实验环境中，可以通过使用体外慢病毒或HIV感染获得进一步的证据。

 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.