Comparative analysis of immune response programmes employed by epithelial cells to fight natural infections in C. elegans

微孢子虫感染会在鱼类、蜜蜂和虾等农业上重要的宿主中引起疾病，导致重大的经济影响。研究简单线虫的免疫反应为更多地了解针对微孢子虫的免疫反应提供了有力的方法。在野外，线虫容易受到微孢子虫病原体细小线虫(来自巴黎的线虫杀手)的感染，导致致命的肠道感染。这项拟议的工作将研究这些病原体是如何被感知来诱导免疫反应的。它将涉及分析肠道中的特定细胞在感染时如何启动基因表达，并包括与英国伦敦的合作者的比较研究，他们正在研究由称为卵菌的自然病原体引起的线虫皮肤感染，这种病原体会导致马铃薯枯萎病等疾病。这些研究将阐明皮肤和肠道细胞如何单独对抗感染，它们如何与整个动物沟通以诱导免疫反应，以及名为PALS-25/PALS-22的开/关开关如何控制这些免疫反应。鉴于微孢子虫感染的普遍存在，这项工作可能会使农业和水产养殖业受益。它将培训研究生和博士后研究员进行跨学科研究，并为来自代表性不足群体的本科生和高中生提供参与尖端研究的机会。此外，由于这项工作将为学生和博士后提供传播机会，在培训下一代科学家如何有效地交流科学成果和建立科学共同体方面将产生更广泛的影响。微孢子虫门包含1400多种专有的细胞内真菌病原体，大多数动物物种被认为容易被一个或多个微孢子虫物种感染。然而，对这些病原体的免疫反应几乎一无所知，这些病原体通常会感染上皮细胞。事实上，对于处于防御第一线的上皮细胞免疫，我们有很多需要了解的东西。线虫严重依赖上皮防御，因为它没有已知的专业免疫细胞，如巨噬细胞或T细胞。在野外，微孢子虫似乎是线虫感染的一种非常常见的原因，特别是一种被称为线虫(来自巴黎的线虫杀手)的物种是自然感染线虫的最常见的物种。Nparisii感染线虫肠道上皮细胞，在那里它诱导一种称为细胞内病原体反应(IPR)的转录免疫反应。通过基因筛选，特罗梅尔实验室和合作者Barkoulas博士的实验室都鉴定出IPR的一个名为PALS-25/PALS-22的开关，他独立地鉴定了PALS-25/PALS-22是对卵菌感染免疫反应的开关，卵菌是线虫表皮的天然病原体。这种反应被命名为卵菌识别反应或ORR。本研究的目的是：1)进行成对的遗传筛选以比较IPR和ORR的调控因子；2)分析IPR和ORR的组织特异性；3)评估IPR和ORR触发因素对PALS-22/PALS-25相互作用的影响。这一美英合作项目得到了美国国家科学基金会和英国生物技术和生物科学研究委员会的支持。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Microsporidia infections cause disease in agriculturally important hosts like fish, honeybees and shrimp, leading to significant economic impacts. Studying immune responses in the simple roundworm C. elegans provides a powerful method to learn more about immune responses against microsporidia. In the wild, C. elegans is subject to infection by the microsporidian pathogen Nematocida parisii (nematode-killer from Paris), which causes a lethal intestinal infection. The proposed work will study how these pathogens are sensed to induce an immune response. It will involve analysis of how specific cells in the intestine turn on gene expression upon infection and includes comparative studies with collaborators in London, UK, who are studying skin infections in C. elegans caused by natural pathogens called oomycetes, which cause diseases like potato blight. These studies will illuminate how skin and intestinal cells fight off infection individually, how they communicate with the entire animal to induce immune responses, and how an ON/OFF switch called PALS-25/PALS-22 controls these immune responses. Given the ubiquity of microsporidia infections, this work may benefit the agriculture and aquaculture industries. It will train graduate students and postdoctoral fellows in interdisciplinary research, as well as provide opportunities for undergraduates and high school students from underrepresented groups to participate in cutting-edge research. Furthermore, because of the opportunities for dissemination that will be available to students and postdocs in this work, there will be broader impacts in training the next generation of scientists in how to effectively communicate scientific results and build scientific community.Microsporidia comprise a phylum containing over 1400 species of obligate intracellular fungal pathogens, and most animal species are thought to be susceptible to infection by one or more microsporidia species. However, almost nothing is known about immune responses against these pathogens, which often infect epithelial cells. Indeed, there is much to be learned about epithelial cell immunity in general, which are on the front lines of defense. The nematode C. elegans relies heavily on epithelial defense, as it has no known professional immune cells like macrophages or T cells. In the wild, microsporidia appear to be a very common cause of infection for C. elegans, and one species in particular called Nematocida parisii (nematode-killer from Paris) is the most common species found naturally infecting C. elegans. N. parisii infects C. elegans intestinal epithelial cells, where it induces a transcriptional immune response named the Intracellular Pathogen Response (IPR). Through genetic screens, an ON/OFF switch for the IPR called PALS-25/PALS-22 was identified both by the Troemel lab, as well as by the lab of collaborator Dr. Barkoulas who independently identified PALS-25/PALS-22 as an ON/OFF switch of an immune response to infection by oomycetes, which are natural pathogens of the C. elegans epidermis. This response has been named the Oomycete Recognition Response or ORR. This study aims to: 1) perform paired genetic screens to compare regulators of the IPR and ORR, 2) analyze tissue-specificity of the IPR and ORR, and 3) assess IPR and ORR triggers for their effects on PALS-22/PALS-25 interactions. This collaborative US/UK project is supported by the US National Science Foundation and the UK Biotechnology and Biological Sciences Research Council.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.