Mechanisms of innate immunity in bony fish

在所有多细胞生物中，先天免疫系统的作用是维持体内平衡和防御病原体。在水产养殖环境中，由于压力和拥挤的条件，鱼类特别容易受到各种病原体的影响。尽管先天免疫在宿主防御病原体中的重要性，但与哺乳动物相比，对鱼类先天免疫的机制知之甚少。先天宿主防御和稳态的重要组成部分是髓系细胞。相对知之甚少的因素，介导的骨髓细胞发育（骨髓）的硬骨鱼，从而限制了我们的理解的稳态过程和免疫系统破坏病原体。拟议的研究计划的第一个目标是在单个细胞和细胞群体水平上表征骨髓生长因子，转录因子和microRNA之间的相互作用。为了实现这一目标，我们建议使用一个独特的金鱼原代肾巨噬细胞培养系统和重组金鱼巨噬细胞生长因子及其受体，我们的特点是在任期内的前NSERC发现赠款。在对感染的反应中，称为巨噬细胞的先天免疫的中心细胞利用许多不同的抗微生物机制来抑制微生物复制并有助于消除病原体。与控制哺乳动物巨噬细胞抗菌反应机制的大量信息相反，对硬骨鱼巨噬细胞抗菌功能的细胞因子调节知之甚少。拟议的研究计划的第二个目标是检查巨噬细胞抗菌反应的调节。我们建议检查识别的细胞内（海洋分枝杆菌，杀鲑气单胞菌）和细胞外（锥虫carassii）鱼病原体的胞质模式识别受体，和金鱼巨噬细胞的抗菌反应的金鱼II型干扰素的调节。我们处于解决这两个目标的极好位置，因为我们（a）开发了从金鱼产生和培养原代巨噬细胞的方法;（B）建立了三种体外和体内金鱼病原体模型系统（M. marinum、海生草A. salmonicida和T. carassii）;和（c）产生并验证金鱼特异性试剂和一组测定，其能够对基因表达、增殖、分化和功能进行单细胞和细胞群体评估。由于天然鱼类资源的枯竭，加拿大的水产养殖业一直以每年20%以上的速度增长。本研究将有助于我们对硬骨鱼先天宿主防御机制的基础知识，这是设计预防鱼类传染病策略所必需的。

In all multicellular organisms, the innate immune system acts to maintain homeostasis and defend against pathogens. In aquaculture setting, fish are especially susceptible to a variety of pathogens due to stress and crowded conditions. Despite the importance of innate immunity in host defense against pathogens, little is known about the mechanisms of fish innate immunity compared to those of mammals. An important component of innate host defence and homeostasis are cells of myeloid lineage. Relatively little is known about the factors that mediate myeloid cell development (myelopoiesis) in bony fish, thus limiting our understanding of homeostatic processes and immune system disruption in response to pathogens. The first objective of the proposed research program is to characterize the interactions between myeloid growth factors, transcription factors and microRNAs during early myelopoiesis at a single cell and at cell population levels. To accomplish this objective, we propose to use a unique goldfish primary kidney macrophage culture system and recombinant goldfish macrophage growth factors and their receptors that we characterized during tenure of a previous NSERC Discovery grant. In response to infection, central cells of innate immunity called macrophages, utilize a number of different antimicrobial mechanisms that inhibit microbial replication and contribute to the elimination of pathogens. In contrast to the large body of information regarding the mechanisms that control mammalian macrophage antimicrobial responses, relatively little is known about cytokine regulation of bony fish macrophage antimicrobial functions. The second objective of the proposed research program is to examine the regulation of antimicrobial responses of macrophages. We propose to examine the recognition of intracellular (Mycobacterium marinum, Aeromonas salmonicida) and extracellular (Trypanosoma carassii) fish pathogens by cytosolic pattern recognition receptors, and regulation of goldfish macrophage antibacterial responses by goldfish Type II interferons. We are in an excellent position to address both objectives because we (a) developed procedures for generation and cultivation of primary macrophages from the goldfish; (b) established three in vitro and in vivo goldfish pathogen model systems (M. marinum, A. salmonicida and T. carassii); and (c) generated and validated goldfish-specific reagents and a panel of assays that enable both single-cell and cell population assessments of gene expression, proliferation, differentiation and function. Due to depletion of natural fish stocks, the aquaculture industry in Canada has been growing at a rate of more that 20% per year. This research will contribute to our basic knowledge of the mechanisms of innate host defense in bony fish that is absolutely required for design of prevention strategies against fish infectious diseases.