The Role of Mucin-type O-glycosylation in Fitness and Transmission of Intestinal Symbiotic Bacteria In Vivo

背景和基本原理。人类肠道是数万亿不同类型细菌的家园。我们现在知道这个庞大的微生物群落在宿主生理中起着许多作用，包括消化、能量获取和维生素生产。然而，我们不清楚宿主如何提供一个环境，让这些有益的细菌在肠道中茁壮成长。一个新出现的因素是肠道粘液，它是由肠壁细胞分泌的，与微生物群混合在一起。这种粘液主要由称为“o -聚糖”的结构组成，它由不同类型的糖分子以独特的构象连接在一起，呈现给微生物群。尽管有了这些知识，我们仍然不清楚这些o -聚糖在促进微生物种群繁荣方面有多重要，这主要是由于缺乏在生命系统中研究它们的有效工具。我们也不知道在o -聚糖如何影响微生物群方面，男性和女性是否存在差异。这给我们对哺乳动物结肠生态系统和种群中有益细菌的维持的理解留下了严重的空白。幸运的是，我们现在有了新的遗传和细菌工具，使我们能够在哺乳动物肠道（小鼠）中操纵o糖基化系统，以及可视化和跟踪特定的细菌反应。目的和方法。我的长期目标是确定宿主分泌粘液的糖基化程序如何影响哺乳动物结肠生态系统，以促进与微生物群的互利相互作用。这项为期五年的发现基金有三个短期目标，重点是宿主o -聚糖如何促进肠道微生物的生存。我的假设是，面对由于饮食和其他干预而导致的腔内环境变化，粘液上的o -聚糖对于促进微生物群的稳定性至关重要。利用我在遗传工具方面的专业知识，在哺乳动物（小鼠）结肠中制造各种o -聚糖缺陷，结合我的“报告菌”，我将使用微生物学、显微镜和计算方法的技术来测试不同的糖基化程序如何影响我的报告菌定植、找到它们的生态位并在男性和女性肠道中茁壮成长的能力。影响和hqp。这些研究将通过解决微生物学和微生物群研究中的一个基本问题，提高加拿大在自然科学领域的国际研究影响力。具体来说，它将产生与对哺乳动物微生物群感兴趣的微生物学家相关的发现；糖生物学家试图了解o -聚糖如何影响微生物群落；研究性别和基于性别的生物学的研究人员，以及希望了解肠道如何帮助支持微生物种群的普通公众。该研究项目还将为加拿大HQP提供一个理想的培训基地，这些HQP将在学术界和工业界具有竞争力。

BACKGROUND AND RATIONALE. The human gut is home to trillions of bacteria of many different types. We know now this vast microbial community plays many roles in host physiology, including digestion, energy acquisition, and vitamin production. However, we are not clear how the host provides an environment that allows such beneficial bacteria to thrive in the gut. One emerging factor is intestinal mucus, which is secreted by cells of the gut lining and intermixes with the microbiota. This mucus is mostly comprised of structures called "O-glycans", which are made up of sugar molecules of different types joined together in unique conformations that are presented to the microbiota. Despite this knowledge, we still are unclear how important these O-glycans are in promoting a thriving microbial population, largely due to the lack of effective tools to study them in a living system. We also do not know whether differences in males and females exist in regards to how O-glycans impact the microbiota. This leaves a serious gap in our understanding of mammalian colon ecosystems and maintenance of beneficial bacteria in a population. Fortunately, we now have access to novel genetic and bacterial tools that allow us to manipulate the O-glycosylation system, as well as visualize and track specific bacterial responses, in a model mammalian gut (mouse). OBJECTIVES AND METHODS. My long-term objective is to determine how the host glycosylation program of the secreted mucus influences the mammalian colon ecosystem to promote mutually beneficial interactions with our microbiota. I have three short-term objectives for this five-year Discovery Grant, which focus on how host O-glycans contribute to microbial survival in the gut. My hypothesis is that the O-glycans on mucus are essential for promoting stability of the microbiota in the face of a changing luminal environment due to dietary and other interventions. Using my expertise with genetic tools to create various O-glycan deficiencies in the mammalian (mouse) colon, in combination with my "reporter" bacteria, I will use techniques in microbiology, microscopy, and computational approaches to test how different glycosylation programs impact the ability of my reporter to colonize, find their niche, and thrive in male and female intestines. IMPACT AND HQP. These studies will boost Canada's international research impact in the natural sciences by addressing a fundamental question in microbiology and microbiota research. Specifically, it will generate findings relevant to microbiologists interested in the mammalian microbiota; glycobiologists seeking to understand how O-glycans impact microbiota communities; researchers studying sex- and gender-based biology, and the general public who wish to understand how their intestines help support their microbial populations. This research program will additionally provide an ideal training ground for Canadian HQP who will be competitive for positions in academia and industry.