STING-dependent activation of Natural Killer cells by viral and tumor DNA

cGAS-STING 通路可感知受感染细胞和癌细胞中的胞质 DNA，并触发 I 型干扰素和其他细胞因子，从而引发免疫反应。该途径的缺陷会阻止 T 细胞对几种病毒和移植肿瘤系的反应。我们的新结果表明该途径是 对于激活针对癌症和病毒感染的自发 NK 细胞反应至关重要。此外，在 通过探索潜在机制，我们的研究发现了一种新的细胞机制，即 cGAS STING 可激活免疫反应。使用遗传方法，我们发现 NK 对 转移的肿瘤细胞依赖于肿瘤细胞中的cGAS表达和宿主细胞中的STING表达。我们 解释这些数据表明 cGAS 激活是感染或转化细胞中发生的关键事件 从而产生环状二核苷酸cGAMP。然后cGAMP从 感染/转化的细胞转化为其他免疫细胞，例如抗原呈递细胞，这些细胞被诱导启动 免疫反应。因此，我们认为细胞间的 cGAMP 转移是一个基本的 免疫激活机制。在考虑 cGAMP 如何在细胞之间转移时，我们假设 特定的膜转运蛋白必须发挥作用。使用全基因组 CRISPRi 筛选，我们鉴定了 专门将 cGAMP 导入细胞的转运蛋白分子。使用一系列基因敲除小鼠和 条件敲除小鼠以及细胞操作和转移，我们建议测试以下要求 NK 和 T 细胞对癌症和 DNA 病毒反应中的 cGAS-STING 信号传导， 病毒感染和癌症模型以及T细胞和NK细胞的转移机制的要求 响应，新识别的转运蛋白在该过程中的作用，并定义特定的细胞 必须导入 cGAMP 才能发生免疫反应。具体来说，我们将：（1）确定站点 cGAMP 和 STING 的作用以及 cGAMP 在抗病毒反应（包括 NK）中的细胞间转移 和 T 细胞反应； (2) 确定cGAMP和STING的作用位点以及细胞间转移 cGAMP 在 T 细胞对癌症的反应、转移模型和 GEM 癌症模型中的作用； (3) 确定角色 cGAMP 转运蛋白在抗病毒、抗肿瘤和免疫反应中的作用。使用条件敲除小鼠 和抑制剂研究，我们将测试它们在抗疱疹病毒和抗肿瘤反应中的功能，包括 GEM 癌症模型。

The cGAS-STING pathway senses cytosolic DNA in infected cells and cancer cells and triggers production of type I interferon and other cytokines, thus eliciting immune responses. Deficiency in the pathway prevents T cell responses to several viruses and to transplanted tumor lines. Our new results show that the pathway is critical for activating spontaneous NK cell responses against cancer, and virus infections. Furthermore, in probing the underlying mechanisms, our research has uncovered a new cellular mechanism whereby cGAS and STING activate immune responses. Using genetic approaches, we found that the NK response to transferred tumor cells depends on cGAS expression in tumor cells and STING expression in host cells. We interpret these data to indicate that cGAS activation is the key event that occurs in infected or transformed cells resulting in the production of the cyclic dinucleotide cGAMP. cGAMP is then transferred from the infected/transformed cells to other immune cells, such as antigen presenting cells, which are induced to initiate the immune response. Hence, we propose that cGAMP transfer between cells is a fundamental mechanism in immune activation. In considering how cGAMP is transferred between cells, we hypothesized that specific membrane transporters must play a role. Using a genome-wide CRISPRi screen, we identified a transporter molecule that specifically imports cGAMP into cells. Using a series of knockout mice and conditional knockout mice, and cellular manipulations and transfers, we propose to test the requirement of cGAS-STING signaling in NK and T cell responses to cancer and DNA viruses, the generality of the requirement of the transfer mechanism in viral infections and cancer models and for T cell and NK cell responses, the roles of the newly identified transporters in the process, and to define the specific cells that must import the cGAMP for immune responses to occur. Specifically, we will: (1) Determine the sites of action of cGAMP and STING and intercellular transfer of cGAMP in anti-viral responses, including NK and T cell responses; (2) Determine sites of action of cGAMP and STING and intercellular transfer of cGAMP in T cell responses to cancer, in transfer models and GEM cancer models; (3) Determine roles of cGAMP transporters in anti-viral and anti-tumor and immune responses. Using conditional knockout mice and inhibitor studies, we will test their function in anti-herpesvirus and anti-tumor responses, including a GEM model of cancer.