Host-associated microbial communities role in innate immune system maturation

描述(由申请人提供)：微生物区系对我们免疫系统的发展是必不可少的，因此对人类健康至关重要。研究已经确定了肠道微生物群落的一些特定成员，它们在辅助免疫系统教育方面具有明确的功能，然而这些研究一直是零散的。关于细菌-细菌相互作用和细菌-宿主相互作用如何影响免疫系统发育，仍有一些悬而未决的问题。我假设，在微生物群落中，细菌与细菌之间的关系改变了细菌与宿主之间的相互作用，从而启动并维持了健康的免疫系统。我建议应用系统生物学的方法来研究寄主-微生物生态系统中的灵生斑马鱼。斑马鱼是灵知生物学研究的一个成熟的模型，在研究细菌与宿主的相互作用方面具有许多优势。最重要的是，它们的肠道微生物区系定义良好，可培养，允许系统地、全面地检查每个物种在免疫反应教育中的个体作用。具体目标：(1)检验对肠道微生物群落的免疫反应不同于对每个成员的个人免疫反应总和的假设。(2)确定分泌的细菌产物是否有助于诱导先天免疫反应。(3)鉴定维罗尼气单胞菌在微生物群落中生存所需的差异基因，与维罗尼亚种单胞菌群落相比较。研究设计：为了比较对单个细菌物种的免疫反应和对微生物群落的免疫反应，我将在一个或两个成员群落的灵知生物学研究中检查肠道中性粒细胞的渗透和宿主转录本。为了检验分泌产物是否是诱导天然免疫的必要条件和充分条件，我将检测肠道中性粒细胞的渗透和对Veronii分泌系统突变的反应和对A.veronii无细胞培养上清的天然免疫基因诱导。最后，为了识别在微生物群落中生存所需的不同的韦罗尼弧菌基因，我将使用在吉列敏实验室开发的韦罗尼弧菌转座子文库。我将把重点放在定植所需的基因上，这些基因不同于维罗尼斯氏菌的单一关联性和与维罗尼斯氏菌和另一种斑马鱼肠道微生物的共同关联性。这种系统的方法将解决微生物群落的集体活动如何教育免疫系统的问题。这些数据对于解释人类微生物组计划的数据、构建益生菌以及将微生物区系操作作为治疗疾病的方法的应用至关重要。

DESCRIPTION (provided by applicant): The microbiota is imperative for the development of our immune system and thus critical for human health. Studies have identified a few specific members of the gut microbial community that have explicit functions in aiding immune system education, however these studies have been piecemeal. Unanswered questions remain regarding how both bacterial-bacterial interactions and bacterial-host interactions affect immune system development. I hypothesize that within microbial community bacterial-bacterial relations alter bacterial-host interactions that initiate and maintain a healthy immune system. I propose to apply a systems biology approach to examine host-microbe ecology in the simplified system of gnotobiotic zebrafish. The zebrafish is a well-established model for gnotobiotic studies, and possesses many advantages for examining bacterial-host interactions. Most importantly, their gut microbiota is well defined and cultureable, allowing a systematic, comprehensive examination of each species' individual role in immune response education. Specific aims: (1) Test the hypothesis that the immune response to a gut microbial community is different than the sum of the individual immune responses to each member. (2) Determine whether secreted bacterial products contribute to the induction of the innate immune response. (3) Identify Aeromonas veronii genes differentially required for survival within a microbial community compared to an A. veronii single species community. Research Design: To compare immune responses to single bacterial species with immune responses to microbial communities I will examine gut neutrophil infiltration and host transcriptomes in gnotobiotic studies with one or two-member communities. To examine whether secreted products are necessary and sufficient to induce innate immunity, I will examine gut neutrophil infiltration and innate immune gene induction in response to an A. veronii secretion system mutant and to A. veronii cell free supernatent. Finally, to identify A. veronii genes differentially required for survival in a microbal community I will employ the A.veronii transposon library developed in the Guillemin lab. I will focus on genes necessary for colonization that differ between a mono- association of A. veronii and a co-association with A. veronii and a second zebrafish gut microbe. This systematic approach will address the question of how collective activities of microbial communities educate the immune system. This data is vital for interpretation of Human Microbiome Project data, construction of probiotics, and application of microbiota manipulations as a therapeutic approach to treat disease.