Studies of Caenorhabditis elegans innate immunity

描述(由申请人提供)：本提案描述了旨在识别和表征秀丽线虫先天免疫信号通路的实验。在过去的几年里，我的实验室率先开发了线虫致病模型，这是基于观察到大量的人类病原菌和酵母杀死线虫。对这些病原体中的每一种都进行了研究，方法是用病原体取代线虫的正常食物来源(大肠杆菌菌株OP50的草坪)，并加班监测线虫的生存情况。这种简单的基于摄食的致病模型与强大的遗传和基因组技术相结合，包括RNAi摄食库，使线虫成为一个有吸引力的模型，在其中剖析免疫反应信号通路。我们已经确定线虫对病原体攻击的应答涉及保守的p38Mark信号通路、含有Toll-InterIL 1受体(TIR)结构域的信号成分、程序性细胞死亡和抗微生物效应蛋白，所有这些都在哺乳动物的先天免疫中发挥作用。利用正向和反向遗传方法，我们已经确定了至少6个线虫基因(TIR-1、NSY-1、SEK-1、MEK-1、VHP-1和PMK-1)，它们在MARK天然免疫信号通路中发挥作用，与在哺乳动物天然免疫反应中发挥作用的p38 MARK信号通路同源。我们还发现DAF-2胰岛素样信号通路在先天免疫信号中发挥作用。在初步数据中，我们已经确定了许多新的基因，它们似乎编码线虫PMK-1(P38)信号途径的额外成分以及其他免疫途径的成分。我们还证明了对致病原介导的杀灭的抵抗力可以独立于整体蠕虫的寿命。这些特异的目的是为了进一步阐明PMK-1(P38)信号通路和其他信号通路在激活线虫免疫反应中的作用，并阐明长寿与病原菌抗性的关系。

DESCRIPTION (provided by applicant): This proposal describes experiments designed to identify and characterize Caenorhabditis elegans innate immune signaling pathways. During the past several years, my laboratory has pioneered the development of C. elegans pathogenicity models based on the observation that a remarkably large number of human pathogenic bacteria and yeasts kill C. elegans. Each of these pathogens has been studied by simply replacing C. elegans' normal food source (a lawn of Escherichia coli strain OP50) with a pathogen, and monitoring the survival of the nematodes overtime. This simple feeding-based pathogenicity model coupled with powerful genetic and genomic technologies, including RNAi feeding libraries, makes C. elegans an attractive model in which to dissect immune response signaling pathways. We have established that the C. elegans response to pathogen attack involves a conserved p38 MARK signaling pathway, a Toll-lnterleukin 1 Receptor (TIR)-domain-containing signaling component, programmed cell death, and antimicrobial effector proteins, all of which also function in mammalian innate immunity. Using both forward and reverse genetic approaches, we have identified at least six C. elegans genes (tir-1, nsy-1, sek-1, mek-1, vhp-1 and pmk-1) that function in a MARK innate immune signaling pathway homologous to the p38 MARK signaling pathway that functions in the mammalian innate immune response. We have also shown that the DAF-2 insulin-like signaling pathway plays a role in innate immune signaling. In preliminary data we have identified a variety of new genes that appear to encode additional components of the C. elegans PMK-1 (p38) signaling pathway as well as components of other immune pathways. We have also demonstrated that resistance to pathogenmediated killing can be independent of overall worm longevity. The specific aims are designed to further elucidate the role of the PMK-1 (p38) signaling pathway and other signaling pathways in activating the C. elegans immune response and to delineate the relationship between longevity and pathogen resistance.