Trans-kingdom cross-talks in the Giardia-infected gut and regulatory effects of the diet

我的NSERC DG程序使用肠道寄生虫贾第鞭毛虫来更好地了解基本的肠道生理学。贾第鞭毛虫是一种人畜共患肠道寄生虫，可引起宠物腹泻，并对家畜造成重大损失。目的：探讨贾第鞭毛虫胞外小泡(EVS)如何改变肠道微生物区系细菌的行为和劫持宿主上皮细胞受体，从而破坏肠道内环境的稳定。然后，研究将确定饮食脂肪可能如何影响这些途径，这与我了解肠道生物学在现实生活中的复杂性的长期目标是一致的。具体目标：1.贾第鞭毛虫EVS的特性：研究将使用最先进的纳米颗粒跟踪、透射电子显微镜、蛋白质组学和小RNA测序来表征贾第虫EVS及其内容物。我们将评估贾第虫EV如何影响微生物群细菌的生长和运动，以促进细菌入侵。2.贾第虫和肠道病毒对宿主细胞受体的影响：我们将确定贾第虫引起的肠道粘液破坏如何与寄生虫激活杯状细胞上的蛋白水解酶激活受体2(PAR-2)有关。研究将表征粘蛋白蛋白对贾第虫的反应。多糖(半乳糖、岩藻糖、唾液酸)在肠道粘液与微生物区系的相互作用中起着关键作用。然后，研究将评估贾第虫电动汽车可能如何牵涉到这些影响。3.贾第鞭毛虫-丛生细胞的相互作用：我们将确定新发现的肠绒毛细胞响应贾第鞭毛虫的动力学和信号机制(受体激活和免疫激活)、对寄生虫负担和微生物区系破坏的后果，并确定这些相互作用如何影响肠道内环境的稳定。4.高脂饮食的影响：利用小鼠贾第虫感染的模型，研究将比较低脂肪或高脂肪“西方”饮食(富含脂肪酸)对感染、炎症、上皮完整性、杯状细胞生物学、肠道运动和粪便水分含量(作为腹泻标志)以及肠道微生物区系完整性的影响。研究将评估膳食脂肪酸(棕榈酸和油酸)对肠道上皮细胞的影响。我们将确定这些膳食脂肪酸如何改变贾第虫电动汽车的生产和特性。研究将比较男性和女性的影响，以更好地了解感染后肠易激综合征等现象的性别依赖。这些发现将有助于设计新的基于饮食的缓解贾第鞭毛虫病的策略，甚至更多。意义：利用贾第虫模型系统，这些研究将揭开肠道内稳态的新的跨王国生理和微生物调节器。这笔赠款将为HQP在研究、政府和工业领域的职业生涯提供大量培训机会，与我的培训记录一致。这些发现将有助于推动加拿大及其他地区的胃肠研究，并为农业部门和加拿大人带来显著好处。

My NSERC DG program uses the intestinal parasite Giardia to better understand basic gut physiology. Giardia is a zoonotic intestinal parasite, causes diarrhea in pets, and is responsible for significant losses in livestock. Objective: To assess how Giardia extracellular vesicles (EVs) alter the behaviour of gut microbiota bacteria and highjack host epithelial receptors to disrupt intestinal homeostasis. Studies will then determine how dietary fat may affect these pathways, consistent with my long-term goal of understanding gut biology in its real-life complexity. Specific objectives: 1. Characterization of Giardia EVs: Studies will characterize Giardia EVs and their contents, using state-of-the art nanoparticle tracking, transmission electron microscopy, proteomics, and small RNA sequencing. We will assess how Giardia EVs affect the growth and motility of microbiota bacteria to facilitate bacterial invasion. 2. Effects of Giardia and EVs on host cell receptors: We will determine how Giardia-induced gut mucus disruptions may implicate activation of Proteinase-Activated Receptor 2 (PAR-2) on goblet cells by the parasite. Studies will characterize glycosylation of mucin proteins in response to Giardia. Glycans (galactose, fucose, sialic acid) play key roles in the interactions of gut mucus with microbiota. Studies will then assess how Giardia EVs may be implicated in the effects. 3. Giardia - tuft cells interactions: We will determine the kinetics and signalling mechanisms (receptor activation and immune activation) of newly discovered intestinal tuft cells in response to Giardia, the consequences on parasite burden and on microbiota disruptions, and determine how these interactions may affect intestinal homeostasis. 4. Effects of a high fat diet: Using models of Giardia infection in mice, studies will compare effects of Low Fat or High Fat "Western" diets (rich in fatty acids) on infection, inflammation, epithelial integrity, goblet cell biology, intestinal motility and fecal water contents as markers of diarrhea, and gut microbiota integrity. Studies will assess effects of dietary fatty acids (palmitic and oleic) on gut epithelia. We will determine how these dietary fatty acids may alter the production and characteristics of Giardia EVs. Studies will compare effects in males and females to better understand the sex-dependence of phenomena such as post-infectious Irritable Bowel Syndrome. The findings will help devise new diet-based mitigation strategies for giardiasis, and beyond. Significance: Using Giardia model systems, the studies will unravel novel trans-kingdom physiological and microbial regulators of intestinal homeostasis. The grant will provide numerous opportunities for HQP training towards careers in research, government, and industry, consistent with my training record. The findings will help advance gastrointestinal research in Canada and beyond, and yield significant benefits to the agricultural sector and to Canadians.