Regulation of the intestinal colonization niche by epithelial cell death

通过上皮细胞死亡调节肠道定植生态位

• 批准号: 10679645
• 负责人: Brittany Marie Miller
• 金额: $ 6.91万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2026-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10679645
• 关键词: Affect; Blood Circulation; CASP8 gene; Cell Death; Cell physiology; Cells; Cellular biology; Colitis; Communicable Diseases; Defect; Development; Disease; Disease Outcome; Disease susceptibility; Disputes; Epithelial Cells; Epithelium; Exposure to; Face; Family; Family member; Future; Gastrointestinal tract structure; Gene Expression; Gene Expression Regulation; Genes; Gnotobiotic; Goals; Growth; Health; Homeostasis; Host Defense; Host Defense Mechanism; Human; Immune response; Immune system; Immunity; In Vitro; Individual; Infection; Inflammatory; Inflammatory Response; Intestines; Lead; Link; Macrophage; Mediating; Methods; Modeling; Mus; Organ; Pathogenesis; Pathway interactions; Physiological; Play; Predisposition; Production; Proteins; Regulation; Research; Research Personnel; Role; Salmonella; Salmonella typhimurium; Side; Signal Transduction; Site; Testing; Thinness; Tissues; Training; Up-Regulation; Work; career; design; differential expression; expectation; experimental study; gastrointestinal infection; gut bacteria; gut colonization; gut inflammation; gut microbiome; gut microbiota; host-associated microbial communities; host-microbe interactions; immune function; in vivo; innovation; interest; intestinal epithelium; member; microbial; microbiome; microbiome research; microbiota; microbiota metabolites; microorganism; mouse model; novel therapeutics; pathogen

Project Summary The intestinal microbiome is made up of trillions of microorganisms that inhabit the gastrointestinal tract. Metabolites produced by the microbiome reach extraintestinal tissues, and can be found in the bloodstream, and are thereby able to influence almost all tissues of the body. Interestingly, the expression of a number of genes of the gastrointestinal tract is dependent on colonization by the microbiome. In this project, we will explore the mechanisms through which the gut microbiome controls gene regulation of intestinal epithelial cells (IECs), through the study of a microbiome-modulated gene involved in IEC cell death. Salmonella enterica serovar Typhimurium (STm) is a pathogen that is adept at overcoming host defenses in order to cause disease. STm triggers an inflammatory response that benefits growth of the pathogen by taking advantage of the host response to infection. Our preliminary findings suggest that STm is able to benefit from a homeostatic microbiome- mediated cell death pathway that has yet to be described. Under steady state conditions, metabolites produced by the microbiome lead to pyroptosis of IECs, which helps maintain normal epithelial turnover. However, upon STm infection, the pathogen harnesses this pathway to elicit increased IEC pyroptosis, leading to increased STm numbers in the gastrointestinal tract. Our early results indicate loss of components of the IEC pyroptosis pathway led to lower STm luminal outgrowth and dissemination to extraintestinal organs, yet, it is unclear how STm activates IEC pyroptosis, and whether this pathway indeed leads to an increase in pyroptosis of intestinal epithelial cells during infection. Thus, I hypothesize that during infection of the gastrointestinal tract, STm takes advantage of a microbiome-controlled homeostatic IEC-specific cell death pathway to bloom to high numbers. In order to elucidate how the microbiome and STm activate IEC pyroptosis, and how this activation leads to cell death and downstream pathogen expansion within the gastrointestinal tract and in extraintestinal sites, we propose two specific aims. In AIM 1 we will assess the contribution of the gut microbiome to induction of IEC pyroptosis, by using a combination of sequencing and in vivo mouse models using conventional and gnotobiotic mice. In AIM 2 we will use mouse infection models to determine how STm elicits IEC pyroptosis during infection, and define the upstream activation pathway. Our mechanistic approach will provide a causal link between the microbiome, a host cell death pathway, and pathogen expansion. Successful completion of this proposal will identify a previously undefined IEC cell death pathway that plays a crucial role under steady state and infectious conditions. This project will additionally expand my training to include key methods and concepts in IEC biology and in the study of the microbiome. Altogether, the research and training plan proposed will facilitate a better understanding of IECs and their role in host immunity, while preparing me for a future career as an independent investigator in the field of host-microbe interactions.

项目概要 肠道微生物组由栖息在胃肠道中的数万亿微生物组成。 微生物组产生的代谢物到达肠外组织，并且可以在血液中找到，并且 因此能够影响身体的几乎所有组织。有趣的是，许多基因的表达 胃肠道的功能依赖于微生物组的定植。在这个项目中，我们将探索 肠道微生物组控制肠上皮细胞（IEC）基因调控的机制， 通过研究参与 IEC 细胞死亡的微生物组调节基因。肠沙门氏菌血清型 鼠伤寒 (STm) 是一种善于克服宿主防御从而引起疾病的病原体。 STm 触发炎症反应，利用宿主反应有利于病原体的生长 到感染。我们的初步研究结果表明，STm 能够受益于稳态微生物组—— 介导的细胞死亡途径尚未被描述。在稳态条件下，产生的代谢物 微生物组导致 IEC 焦亡，这有助于维持正常的上皮更新。然而，基于 STm 感染，病原体利用该途径引起 IEC 细胞焦亡增加，从而导致 STm 增加 胃肠道中的数量。我们的早期结果表明 IEC 细胞焦亡途径的成分丢失 导致较低的 STm 管腔生长和传播到肠外器官，然而，尚不清楚 STm 如何 激活 IEC 焦亡，以及该途径是否确实导致肠道焦亡增加 感染期间的上皮细胞。因此，我推测在胃肠道感染期间，STm 会 利用微生物组控制的稳态 IEC 特异性细胞死亡途径来大量繁殖。 为了阐明微生物组和 STm 如何激活 IEC 细胞焦亡，以及这种激活如何导致 细胞死亡和下游病原体在胃肠道内和肠外部位的扩张， 我们提出两个具体目标。在 AIM 1 中，我们将评估肠道微生物组对 IEC 诱导的贡献 细胞焦亡，通过结合使用测序和体内小鼠模型，使用常规和限生素 老鼠。在 AIM 2 中，我们将使用小鼠感染模型来确定 STm 在感染过程中如何引发 IEC 细胞焦亡， 并定义上游激活途径。我们的机械方法将提供之间的因果联系 微生物组、宿主细胞死亡途径和病原体扩张。本提案的顺利完成将 确定以前未定义的 IEC 细胞死亡途径，该途径在稳态和传染性下发挥着至关重要的作用 状况。该项目还将扩展我的培训范围，包括 IEC 生物学中的关键方法和概念 以及微生物组的研究。总而言之，所提出的研究和培训计划将有助于更好地 了解 IEC 及其在宿主免疫中的作用，同时为我未来作为独立人员的职业生涯做好准备 宿主-微生物相互作用领域的研究者。