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

描述（由申请方提供）：识别宿主细胞胞质溶胶中的外源DNA对于启动针对DNA病毒的免疫应答至关重要。病毒DNA的识别激活了许多信号通路，包括诱导有效的抗病毒细胞因子，如I型干扰素。虽然胞质DNA传感途径进化为检测病毒，但我们最近的初步数据也表明，STING的DNA依赖性激活在对肿瘤的反应中也可能是至关重要的。在这里，我们建议调查如何识别胞质DNA导致激活的抗肿瘤和抗病毒反应的自然杀伤（NK）细胞。我们的总体假设是，DNA的胞质检测是NK细胞先天识别病毒和肿瘤的常见机制。我们描述了三个目标，将阐明cGAS-STING途径如何启动抗病毒和抗肿瘤反应。这些目标代表了Raulet实验室和Russell万斯顾问实验室之间的密切合作，Raulet实验室拥有NK细胞和NKG 2D激活受体的专业知识，Russell Vance实验室拥有细胞溶质DNA传感和STING途径的专业知识。目的如下：（1）确定cGAS-STING途径如何在体内激活NK细胞和其他免疫细胞。我们的初步数据显示，通过HSV-1或合成的2 '3'-cGAMP的STING接合在体内激活NK细胞和其他免疫细胞。STING活化导致I型IFN、STAT 6依赖性趋化因子的产生和NKG 2D配体的活化。将使用各种敲除小鼠在体内确定将这些途径与NK活化联系起来的机制以及所涉及的细胞类型。(2)确定cGAS-STING信号传导是否是肿瘤先天免疫控制所必需的。携带E-myc转基因的小鼠将与cGAS-STING信号通路缺陷的小鼠杂交，这些小鼠会发生B细胞淋巴瘤。我们将确定cGAS-STING的丢失是否会加速该模型中的肿瘤发生。我们假设cGAS-STING信号传导是肿瘤细胞和可能的APC表达激活NK细胞受体的配体（例如，NKG 2D和DNAM 1）。(3)确定DNA损伤导致胞浆DNA积累的机制。我们的初步数据表明，经历DNA损伤或经历转化的细胞表现出主要来源于内源性逆转录病毒/元件的胞质DNA的增加和异常积累。在该目的中，我们将评估胞质DNA增加是否是由于逆转录病毒/元件RNA的表达增加，和/或胞质逆转录酶活性增加，和/或胞质DNA核酸外切酶（例如，TREX1）。

DESCRIPTION (provided by applicant): Recognition of foreign DNA in the cytosol of host cells is critical for the initiation of immune responses to DNA viruses. Recognition of viral DNA activates numerous signaling pathways, including the induction of potent antiviral cytokines such as type I interferons. Although the cytosolic DNA-sensing pathway evolved to detect viruses, our recent preliminary data also suggest that DNA-dependent activation of STING may also be critical in the response to tumors. Here we propose to investigate how recognition of cytosolic DNA leads to activation of anti-tumor and anti-viral responses by Natural Killer (NK) cells. Our overall hypothesis is that cytosolic detection of DNA is a common mechanism underlying innate recognition of viruses and tumors by NK cells. We describe three Aims that will illuminate how the cGAS-STING pathway initiates anti-viral and anti-tumor responses. These Aims represent a close collaboration between the Raulet Lab, which has expertise in NK cells and the NKG2D activating receptor, and the lab of consultant Russell Vance, which has expertise in cytosolic DNA sensing and the STING pathway. The Aims are as follows: (1) Determine how the cGAS-STING pathway activates NK cells and other immune cells in vivo. Our preliminary data show that STING engagement by HSV-1 or synthetic 2'3'-cGAMP activates NK cells and other immune cells in vivo. STING activation leads to production of type I IFN, STAT6-dependent chemokines, and activation of NKG2D ligands. The mechanisms linking these pathways to NK activation, and the cell types involved, will be determined in vivo using various knockout mice. (2) Determine if cGAS-STING signaling is required for innate immune control of tumors. Mice harboring an E¿-myc transgene, which develop B cell lymphomas, will be crossed to mice deficient in the cGAS-STING signaling pathway. We will determine whether loss of cGAS-STING accelerates tumorigenesis in this model. We hypothesize that cGAS-STING signaling is required for tumor cell and possibly APC expression of ligands that activate NK cell receptors (e.g., NKG2D and DNAM1). (3) Determine the mechanisms by which DNA damage leads to accumulation of cytosolic DNA. Our preliminary data indicate that cells experiencing DNA damage or undergoing transformation exhibit increased and aberrant accumulation of cytosolic DNA derived largely from endogenous retroviruses/elements. In this Aim we will assess whether increased cytosolic DNA is due to increased expression of retrovirus/element RNA, and/or increased cytosolic reverse transcriptase activity, and/or decreased activity of cytosolic DNA exonucleases (e.g., TREX1).