cGAMP as an immunotransmitter of the interferon response to UV light

项目摘要 这个项目的长期目标是确定cGAS-STING途径和cGAS-STING途径的作用 信使环二核苷酸cGAMP作为干扰素反应的局部和系统免疫递质 皮肤暴露在UVB光下后。此外，我们试图确定这些观察结果的意义 在系统性红斑狼疮的相关小鼠模型中。 系统性红斑狼疮患者的特征是外周血细胞中有I型干扰素(干扰素-I)信号，这 同样的特征在皮损和非皮损皮肤中也很明显。虽然人们通常认为系统性的 免疫激活导致干扰素-I反应扩散到组织，我们观察到，在单一的 暴露在紫外线(UVB)下，UVB不仅在皮肤中诱导干扰素签名，而且在血液中也诱导干扰素签名 野生型小鼠的肾脏。因为我们观察到紫外线照射后不久产生的干扰素-I需要DNA 激活的细胞质感受器cGAS，我们假设cGAMP，环二核苷酸合成的产物 CGAS本身是一种免疫递质，负责局部和系统地传播干扰素-I反应。 在这项建议中，我们探讨了UVB刺激cGAMP的产生如何导致干扰素签名在 皮肤，检查对引流淋巴结局部免疫反应的影响，并寻找cGAMP 野生型和狼疮易感菌株的依赖组织炎症。为了实现这些目标，我们采取了 CGAS或ENPP1基因缺陷小鼠的优势 从细胞输出后分解cGAMP的磷酸二酯酶-1)和利用可以开发的试剂 来操纵cGAS刺痛途径。我们专门审问cGAMP转运蛋白：连接蛋白， SLC19A1和容量调节阴离子通道(VRAC)LRRC8，以确定哪些转运体控制 CGAMP的传播以及在什么条件下。 这些研究的意义在于，它们将有助于确定遗传和分子机制 负责UVB诱导干扰素-I，定义信号如何传播，并可能指示狼疮发作的方式 发生在暴露于UVB之后。此外，这项研究的重点是一种酶，ENPP1，它还没有 以前是在自身免疫的背景下研究的，如果被证明是重要的，可以被利用 从治疗上阻止cGAMP扩散。这些研究可能逆转系统性干扰素-I引起的范式 皮肤上的干扰素签名。因为我们在系统性红斑狼疮患者的血液中检测到cGAMP 红斑狼疮(SLE)，这些研究结果将具有很强的翻译意义。

Project Summary The long-term goals of this project are to determine the role of the cGAS-STING pathway and the messenger cyclic dinucleotide cGAMP, as a local and systemic immunotransmitter of the IFN response following skin exposure to UVB light. In addition, we seek to determine the significance of these observations in a relevant mouse model of SLE. SLE patients characteristically have a type I interferon (IFN-I) signature in peripheral blood cells and this same signature is prominent in lesional and non-lesional skin. While it is generally assumed that systemic immune activation leads to dissemination of the IFN-I response to tissues, we observed that, following a single exposure to ultraviolet light (UVB), UVB induces an IFN signature not only in the skin but also in the blood and kidneys of wild type mice. Since we observed that IFN-I produced soon after UV exposure requires the DNA activated cytoplasmic sensor cGAS, we hypothesize that cGAMP, the cyclic dinucleotide synthetic product of cGAS, is itself an immunotransmitter that is responsible for spreading the IFN-I response locally and systemically. In this proposal, we explore how UVB stimulated cGAMP production leads to spreading of the IFN signature in the skin, examine the effects on local immune response in the draining lymph nodes, and look for cGAMP dependent tissue inflammation in both wild type and lupus-prone strains. To achieve these Aims, we take advantage of genetically modified mice that are deficient in cGAS or ENPP1 (ectonucleotide pyrophosphatase phosphodiesterase-1 that hydrolyzes cGAMP after export from cells) and utilize reagents that can be exploited to manipulate the cGAS-STING pathway. We specifically interrogate the cGAMP transporters: connexins, SLC19A1 and the Volume Regulated Anion Channel (VRAC) LRRC8, to determine which transporters control cGAMP spreading and under what conditions. The significance of these studies are that they will help define the genetic and molecular mechanisms responsible for UVB induction of IFN-I, define how the signal spreads and, possibly, indicate how lupus flares occur following exposure to UVB. In addition, the research focuses on an enzyme, ENPP1, that has not previously been studied in the context of autoimmunity and, if shown to be important, could be harnessed therapeutically to abort cGAMP spreading. These studies could reverse the paradigm that systemic IFN-I causes the skin IFN signature. Since we have detected cGAMP in blood of a subset of patients with systemic lupus erythematosus (SLE), the results of these studies will have strong translational significance.