Mechanistic Studies of Cytoplasmic dsDNA-Sensing Pathways

项目摘要 dsDNA在细胞质中的存在标志着真核细胞中的严重问题， 从线粒体功能失调到病原体入侵在哺乳动物中，先天免疫系统 检测到这些流氓dsDNA并引发炎症反应。胞质dsDNA传感 途径是宿主防御多种病原体的组成部分，它们的功能障碍是 也与各种人类疾病有关。 在这里，我们将定义细胞质dsDNA传感器启动的分子机制， 宿主的先天免疫反应协调一致。在目标1中，我们将解决几个 关于cGAS激活机制的争议，例如为什么dsDNA长度很重要 (or不），N结构域的作用是什么，以及cGAS如何在dsDNA上二聚化。在目标2中，我们 解决先天免疫学中的一个基本机制问题，即什么定义了 cGAS、AIM 2和IFI16的dsDNA特异性。然后，我们将测试细胞RNA是否可以作为 一个缓冲区，以尽量减少这些传感器的虚假激活。在目标3中，我们将确定 cGAS、AIM2、IFI16和TREX1核酸酶的差异动力学是否可以塑造 针对胞质dsDNA的总体宿主应答。然后我们将研究激动作用， 这些传感器之间的拮抗作用在产生良好平衡的宿主反应， 胞质双链DNA

Project summary The presence of dsDNA in the cytoplasm signals serious problems in eukaryotic cells, ranging from dysfunctional mitochondria to pathogen invasion. In mammals, the innate immune system detects these rogue dsDNA and initiate inflammatory responses. Cytoplasmic dsDNA sensing pathways are integral to host defense against numerous pathogens, and their malfunctions are also implicated in various human maladies. Here, we will define the molecular mechanisms by which cytoplasmic dsDNA sensors initiate host innate immune responses in a coordinated fashion. In Aim 1, we will resolve several controversies regarding the activation mechanism of cGAS such as why dsDNA length matters (or not), what the role of N-domain is, and how cGAS dimerizes on dsDNA. In Aim 2, we will resolve a fundamental mechanistic question in innate immunology as to what defines the dsDNA specificity of cGAS, AIM2, and IFI16. We will then test whether cellular RNA can act as a buffer to minimize the spurious activation of these sensors. In Aim 3, we will determine whether differential kinetics of cGAS, AIM2, IFI16, and the TREX1 nuclease can shape the overall host response against cytoplasmic dsDNA. We will then investigate agonism and antagonism among these sensors in generating well-balanced host responses against cytoplasmic dsDNA.