MCA: Integrating immune system and microbiome function during amphibian development

MCA：在两栖动物发育过程中整合免疫系统和微生物组功能

• 批准号: 2123583
• 负责人: Valerie McKenzie
• 金额: $ 35.84万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2123583&HistoricalAwards=false
• 关键词: MCA; Integrating; immune; system; microbiome

Microbial organisms, such as bacteria, often live in a symbiotic relationship with animals and provide beneficial functions that support health of the host animals. For many of these bacterial and animal symbiotic relationships, we know very little about their specific biology and what kinds of beneficial functions the symbiotic partners provide. Like most vertebrate animals, amphibians have complex immune systems with innate and adaptive immune functions, however amphibians do not develop a fully capable immune system until after they metamorphose from the aquatic tadpole life stage. The investigator proposes a novel hypothesis postulating that the symbiotic skin bacteria on aquatic tadpoles provide protective defensive functions while the immune system is not yet mature. The project will test this idea using an experimental approach that will examine the immune system and bacterial symbionts of an amphibian during its development from the egg and tadpole stages through metamorphosis. The Colorado Boreal Toad will be featured in this work, and it is locally endangered in the Southern Rocky Mountains due to a fungal skin pathogen. This project will advance understanding of the ways in which Boreal Toads defend themselves against the pathogen which can be helpful for conservation of the species. The investigator is a mid-career scientist who will work with a collaborator and mentor to expand learning how to apply immunology methods to amphibian disease research. The investigator is also dedicated to service in her position to support diversity, equity and inclusion as the director of graduate studies in her unit. Host-associated microbes provide a range of beneficial and necessary functions for their host organisms, yet the processes that drive the assembly of host-associated microbial communities is a significant knowledge gap. This project will study microbiome function on the skin of amphibians in order to examine the role of symbiotic microbes in pathogen defense and how that functioning changes during amphibian development. Growing a complex immune system that is capable of targeting and ridding harmful pathogens takes significant developmental time, and most of the adaptive immune system of amphibians does not come online until after metamorphosis. This begs the question, how do larval, aquatic amphibians defend themselves against a sea of opportunistic pathogens prior to the full functioning of the immune system? This project will test the idea that larval amphibians assemble a symbiotic microbial community with pathogen defense as a primary function, the ‘microbial surrogate defense system hypothesis’, prior to the maturation of the immune system. The investigator proposes a time-series experiment that will track the symbiotic skin bacteria and immune function during boreal toad development and conduct three pathogen challenge trials that will occur before, during, and after metamorphosis, respectively. The project will use both culture-dependent and sequencing tools to characterize the bacterial symbionts and immunogenomic and transcriptomic tools to characterize immune function. This project represents a first-time collaboration between the PI and a research Partner who will provide expertise on amphibian immunogenetic tools as well as mentoring related to career advancement for the PI.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.

微生物，如细菌，通常与动物共生，并提供有益的功能，支持宿主动物的健康。对于许多细菌和动物的共生关系，我们对它们的具体生物学和共生伙伴提供的有益功能知之甚少。像大多数脊椎动物一样，两栖动物具有复杂的免疫系统，具有先天和适应性免疫功能，然而两栖动物直到从水生蝌蚪生命阶段蜕变后才发育出完全有能力的免疫系统。研究者提出了一种新的假设，即在免疫系统尚未成熟的时候，水生蝌蚪皮肤上的共生细菌具有保护防御功能。该项目将使用一种实验方法来验证这一想法，该方法将检查两栖动物从卵和蝌蚪阶段到变态发育过程中的免疫系统和细菌共生体。科罗拉多北方蟾蜍（Colorado Boreal Toad）将出现在这部作品中，由于一种皮肤真菌病原体，它在落基山脉南部的当地濒临灭绝。该项目将促进对北方蟾蜍防御病原体的方式的理解，这对物种的保护有帮助。该研究人员是一名处于职业生涯中期的科学家，他将与一位合作者和导师一起扩大学习如何将免疫学方法应用于两栖动物疾病研究。作为她所在单位的研究生研究主任，调查员还致力于在她的职位上为支持多样性，公平性和包容性提供服务。宿主相关微生物为其宿主生物提供了一系列有益和必要的功能，但驱动宿主相关微生物群落组装的过程是一个重大的知识空白。本项目将研究两栖动物皮肤上微生物组的功能，以研究共生微生物在防御病原体中的作用以及这种功能在两栖动物发育过程中的变化。培养一个能够靶向和清除有害病原体的复杂免疫系统需要大量的发育时间，而且大多数两栖动物的适应性免疫系统直到变态之后才开始在线。这就引出了一个问题，在免疫系统完全发挥作用之前，水生两栖动物的幼虫如何保护自己免受大量机会性病原体的侵害？该项目将验证一种观点，即在免疫系统成熟之前，两栖动物幼虫聚集了一个以病原体防御为主要功能的共生微生物群落，即“微生物替代防御系统假说”。研究者提出了一个时间序列实验，将跟踪北方蟾蜍在发育过程中的共生皮肤细菌和免疫功能，并分别在变态前、变态中和变态后进行三次病原体挑战试验。该项目将使用培养依赖性和测序工具来表征细菌共生体，并使用免疫基因组学和转录组学工具来表征免疫功能。该项目是PI与研究伙伴之间的首次合作，该合作伙伴将提供两栖动物免疫遗传学工具方面的专业知识，并为PI提供与职业发展相关的指导。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。