Understanding the molecular mechanisms of Akkermansia glycan-binding adhesins in shaping microbial communities and balancing intestinal inflammation in response to host signals

项目摘要/摘要 粘液阿克曼氏菌是一种驻留在人体肠道中的细菌，与预防 慢性炎症性疾病，如炎症性肠病、结直肠癌和2型糖尿病。 决定粘液假单胞菌如何进入肠道以及如何促进宿主的分子机制 健康状况不得而知。粘液杆菌生长在致密的聚集体中，与富含多糖的粘蛋白紧密结合。 肠子的内层。当在粘液培养基中培养时，粘液杆菌产生抗炎化合物。 并刺激其他被糖衣的肠道微生物，如瘤胃球菌，产生丁酸盐，一种发酵 具有治疗作用的副产品。这个项目的董事会和长期目标是了解如何 肠道的葡聚糖环境塑造了粘液杆菌的抗炎活性和解码物种- 驱动临床分离株变异的水平机制。这项工作具有广泛的领域意义 例如，旨在治疗炎症性疾病的益生菌和治疗开发。这件事的重点是 建议发展一种分子上的理解，了解粘液弧菌菌株如何调节不同的 糖链结合细胞表面粘附素，称为含PbH1的粘附素(PbHAs)，与粘蛋白结合 肠道环境，与其他共生菌相互作用和操纵丁酸发酵，以及 调节宿主体内的先天免疫途径。在特定的目标1中，我将设计一种斑马鱼细菌共生体 表达由两种感兴趣的粘液嗜酸杆菌(MUT和MUT)编码的七种不同的PbHa AKK2750)，并测试表情如何在培养中塑造它们的聚集特性并影响它们的空间 斑马鱼幼体肠道中的组织。此外，我将使用实验进化来揭示遗传途径 促使MUMT和AKK2750在粘蛋白介质中聚集。具体目标2将调查PbHa的作用 并确定MUMT和AKK2750是如何感知粘蛋白和共聚集的 利用革兰氏酵母影响丁酸发酵。最后，《特定目标3》将使用斑马鱼的微生物模型。 诱导肠道炎症以确定PbHAs和其他物种特有的减轻炎症的因素 并促进肠道健康。我将使用一种针对病原体的PbHA来设计治疗珠子，它可以结合和 清除肠道病原体，恢复肠道健康。我将发现的分子洞察力，研究试剂 我将产生，我将通过这些学习获得的技能将使我能够建立自己的独立 研究微生物群介导的人类健康的分子机制的研究实验室。

PROJECT SUMMARY/ABSTRACT Akkermansia muciniphila is a bacterial resident of the human intestine that is associated with protection from chronic inflammatory diseases such as inflammatory bowel diseases, colorectal cancers, and type-2 diabetes. The molecular mechanisms that determine how A. muciniphila inhabits the intestine and how it promotes host health are not known. A. muciniphila grows in dense aggregates in tight association with the glycan-rich mucin lining of the intestine. When cultured in mucin medium, A. muciniphila produces anti-inflammatory compounds and stimulates other glycan-coated gut microbes like Ruminococcus gnavus to produce butyrate, a fermentation byproduct with therapeutic properties. The board and long-term objective of this project is to learn how the glycan environment of the intestine shapes A. muciniphila’s anti-inflammatory activities and decode species- level mechanisms that drive variability among clinical isolates. This work has wide-reaching implications in fields such as probiotic and therapeutic development aimed at treating inflammatory diseases. The focus of this proposal is to develop a molecular understanding of how A. muciniphila strains regulate a diverse group of glycan-binding cell surface adhesins referred to as PbH1-containing adhesins (PbHAs) to engage with the mucin environment of the intestine, to interact with and manipulate butyrate fermentation in other symbionts, and to modulate innate immune pathways in the host. In Specific Aim 1 I will engineer a zebrafish bacterial symbiont to express each of the seven diverse PbHAs encoded by two A. muciniphila species of interest (MucT and AKK2750) and test how expression shapes their aggregation properties in culture and influences their spatial organization in the larval zebrafish gut. Further, I will use experimental evolution to uncover the genetic pathways that drive MucT and AKK2750 aggregation in mucin medium. Specific Aim 2 will investigate the role of PbHAs in co-aggregation with R. gnavus and determine how MucT and AKK2750 mucin-sensing and co-aggregation with R. gnavus influence butyrate fermentation. Lastly, Specific Aim 3 will use a zebrafish model of microbe- induced intestinal inflammation to identify PbHAs and other species-specific factors that reduce inflammation and promote intestinal health. I will use a pathogen-targeting PbHA to design therapeutic beads that bind and deplete an intestinal pathogen and restores gut health. The molecular insights I will discover, research reagents I will generate, and skills I will acquire through these studies will position me to establish my own independent research laboratory investigating the molecular mechanisms of microbiome-mediated human health.