C. elegans model of B. anthracis immunity & pathogenesis

描述（由申请方提供）：炭疽芽孢杆菌是一种普遍存在的土壤细菌，是导致炭疽的NIAID A类病原体。虽然研究已经揭示了对这种致命细菌的重要见解（例如，三重毒素的活性），炭疽病的发病机理至今仍有待令人满意的解释，我们还有很多不了解的地方。对致病性重要的染色体因素研究不足，我们对先天免疫系统如何保护免受炭疽感染知之甚少。我们已经证明了B。炭疽菌可对土壤线虫和模式无脊椎动物C.优雅这一发现开辟了利用正向和反向遗传学以前所未有的规模研究炭疽感染的可能性。B。炭疽菌可以感染线虫并在线虫体内增殖，最终从内到外吞噬线虫。C.然而，秀丽线虫具有与哺乳动物相同的许多途径和效应器机制的强有力的先天免疫系统。在某些情况下，线虫似乎能够产生有效的抗B的免疫应答。炭疽病该方案将利用这种新颖的C.埃里冈湾炭疽系统，以确定，在前所未有的规模，（i）宿主基因参与先天防御B。炭疽菌感染和B.炭疽病基因参与建立感染和规避先天防御在一个完整的动物。将使用亲和微阵列来鉴定响应于B而上调的潜在宿主免疫基因。炭疽感染。这些基因将在C. elegans使用RNAi。将筛选给药动物对B的超敏反应。炭疽感染，以确定参与先天防御的新基因。对C.对B高度敏感的线虫突变体。炭疽感染也将进行。在等式的病原体方面，B的随机转座子和/或质粒整合突变体文库。将在高通量C.秀丽隐杆线虫感染测定。将筛选无毒突变体在鼠巨噬细胞内的生长，作为对哺乳动物中潜在致病性降低的初步评估。该R21研究的结果将产生新的试剂和假设，以在未来关于B的R-01或P-01提案中进行探索。炭疽毒力机制和相关的宿主先天防御，包括直接延伸到哺乳动物模型系统。

DESCRIPTION (provided by applicant): Bacillus anthracis is a ubiquitous soil bacterium and NIAID category A pathogen that causes anthrax. Although research has revealed important insights into this deadly bacterium (e.g., the activity of the tripartite toxins), the pathogenesis of anthrax has yet to be satisfactorily explained and there is much we do not understand. Chromosomal factors important for pathogenicity have been understudied, and we know very little about how the innate immune system acts to protect against anthrax infection. We have demonstrated that B. anthracis can produce a lethal infection in the soil nematode and model invertebrate C. elegans. This discovery opens up the possibility to study anthrax infection using forward and reverse genetics on an unprecedented scale. B. anthracis can infect and proliferate inside the nematode, eventually devouring it from the inside out. C. elegans, however, has a potent innate immune system that shares many pathways and effector mechanisms with that of mammals. The nematode appears capable in some cases of mounting an effective immune response against B. anthracis. This proposal will exploit this novel C. elegans-B. anthracis system to identify, on an unprecedented scale, (i) host genes involved in innate defense against B. anthracis infection and (ii) B. anthracis genes involved in establishing infection and circumventing innate defenses in an intact animal. Affymetrix microarrays will be used to identify potential host immunity genes up-regulated in response to B. anthracis infection. These genes will be systematically knocked down in C. elegans using RNAi. Treated animals will be screened for hypersensitivity to B. anthracis infection in order to identify novel genes involved in innate defense. A large-scale genetic screen for C. elegans mutants hypersensitive to B. anthracis infection will also be performed. On the pathogen side of the equation, random transposon and/or plasmid integrational mutant libraries of B. anthracis will be generated and screened for virulence attenuation in a high-throughput C. elegans infection assay. Avirulent mutants will be screened for growth within murine macrophages as a preliminary assessment of potential reduced pathogenicity in mammals. Results from this R21 study will generate novel reagents and hypotheses to be explored in a future R-01 or P-01 proposal on B. anthracis virulence mechanisms and relevant host innate defenses, including direct extension into mammalian model systems.