Mechanistic Studies of Cytoplasmic dsDNA-Sensing Pathways

项目总结 细胞质中dsdna的存在标志着真核细胞中存在严重的问题，包括 线粒体功能障碍导致病原体入侵。在哺乳动物中，先天免疫系统检测到这些无赖 DsDNA和启动炎症反应。细胞质dsDNA传感通路是寄主不可或缺的 对许多病原体的防御，以及它们的故障也与各种人类疾病有关。 在这里，我们将定义细胞质dsdna传感器启动宿主先天的分子机制。 以协调的方式进行免疫反应。在目标1中，我们将解决关于 CGAS的激活机制，如为什么dsDNA长度重要(或不重要)，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，我们将解决先天的一个基本的机械问题 免疫学关于cGAS、AIM2和IFI16的dsDNA特异性的定义。然后我们将测试一下 细胞RNA可以起到缓冲作用，最大限度地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整体 寄主对胞质dsDNA的反应。然后我们将调查这些人之间的竞争和对抗 传感器在产生针对细胞质dsdna的平衡宿主反应中的作用。

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.