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隐杆线虫先天免疫信号通路的实验。在过去的几年里，我的实验室在观察到大量的人类致病菌和酵母杀死秀丽隐杆线虫的基础上，率先开发了秀丽隐杆线虫的致病性模型。每一种病原体都是通过简单地用病原体代替秀丽隐杆线虫的正常食物来源（大肠杆菌菌株OP50的草坪），并长期监测线虫的存活情况来研究的。这种简单的基于摄食的致病性模型加上强大的遗传和基因组技术，包括RNAi摄食文库，使秀丽隐杆线虫成为解剖免疫反应信号通路的有吸引力的模型。我们已经确定秀丽隐杆线虫对病原体攻击的反应涉及保守的p38 MARK信号通路、含有toll -白细胞介素1受体（TIR）结构域的信号通路、程序性细胞死亡和抗菌效应蛋白，所有这些也在哺乳动物先天免疫中起作用。使用正向和反向遗传方法，我们已经确定了至少六个线虫基因（tir-1, nsy-1, sek-1, mek-1， vhp-1和pmk-1），它们在MARK先天免疫信号通路中起作用，与哺乳动物先天免疫应答中的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传导中发挥作用。在初步数据中，我们已经确定了多种新的基因，这些基因似乎编码秀丽隐杆线虫PMK-1 （p38）信号通路的其他成分以及其他免疫途径的成分。我们还证明了对病原体介导的杀伤的抗性可以独立于蠕虫的总体寿命。具体目的是进一步阐明PMK-1 （p38）信号通路和其他信号通路在激活秀丽隐杆线虫免疫应答中的作用，并描述寿命与病原体抗性之间的关系。

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.