Department of Medical Microbiology & Immunology, University of Wisconsin-Madison, Madison, WI 53706, USA.
Department of Pediatrics, University of Wisconsin-Madison, Madison, WI 53706, USA.
Cell Host Microbe. 2023 Sep 13;31(9):1552-1567.e8. doi: 10.1016/j.chom.2023.08.001. Epub 2023 Aug 30.
Host:pathogen interactions dictate the outcome of infection, yet the limitations of current approaches leave large regions of this interface unexplored. Here, we develop a novel fitness-based screen that queries factors important during the middle to late stages of infection. This is achieved by engineering influenza virus to direct the screen by programming dCas9 to modulate host gene expression. Our genome-wide screen for pro-viral factors identifies the cytoplasmic DNA exonuclease TREX1. TREX1 degrades cytoplasmic DNA to prevent inappropriate innate immune activation by self-DNA. We reveal that this same process aids influenza virus replication. Infection triggers release of mitochondrial DNA into the cytoplasm, activating antiviral signaling via cGAS and STING. TREX1 metabolizes the DNA, preventing its sensing. Collectively, these data show that self-DNA is deployed to amplify innate immunity, a process tempered by TREX1. Moreover, they demonstrate the power and generality of pathogen-driven fitness-based screens to pinpoint key host regulators of infection.
宿主-病原体相互作用决定了感染的结果，但目前的方法存在局限性，使得这一界面的很大一部分未被探索。在这里，我们开发了一种新颖的基于适应性的筛选方法，用于研究感染中后期重要的因素。通过工程化流感病毒，我们实现了这一目标，通过编程 dCas9 来调节宿主基因表达，从而引导筛选。我们进行了全基因组筛选以寻找促进病毒的因素，发现了细胞质 DNA 外切酶 TREX1。TREX1 降解细胞质 DNA，防止自身 DNA 引起不适当的先天免疫激活。我们揭示了这个相同的过程有助于流感病毒的复制。感染触发线粒体 DNA 释放到细胞质中，通过 cGAS 和 STING 激活抗病毒信号。TREX1 代谢 DNA，防止其被感知。总的来说，这些数据表明，自身 DNA 被用来放大先天免疫，而 TREX1 则对其进行了调节。此外，它们还展示了病原体驱动的适应性筛选在确定感染关键宿主调节剂方面的强大功能和通用性。
