The role of host-derived reactive oxygen species in the outgrowth of Escherichia coli during non-infectious colitis

项目摘要 患有炎症性肠病（IBD）的患者经历炎症的复发期和缓解期， 他们的胃肠道。在炎症期间，许多患者表现出结肠微生物 导致兼性厌氧菌（主要是肠杆菌科的成员）增加的群落 家庭，如E. coli）。在肠道微生物群组成的类似变化在小鼠模型中观察到， 结肠炎我们实验室以前的工作表明，肠杆菌科细菌种群的扩张可以 通过抑制这些细菌利用的两种代谢途径， 炎症抑制这种肠杆菌科菌群减少肠道炎症。这一发现表明 微生物生态失调会加重炎症，导致宿主结果较差，并支持 特异性地靶向微生物群作为改善疾病的手段。本研究的目的是进一步 阐明兼性厌氧菌在炎症条件下生长的代谢途径。 我的初步数据表明，宿主衍生的活性氧与 种和肠杆菌科的副产物。我假设活性氧允许兼性 厌氧肠杆菌科在发炎的肠腔中呼吸。这项建议的具体目标是 (1)确定宿主衍生的活性氧在E.小鼠大肠杆菌 结肠炎模型和（2）确定细胞色素bd-II氧化酶（AppBC）和 体外活性氧为了验证我的假设，我将使用宿主和细菌的策略组合 在化学诱导和遗传结肠炎模型中的遗传学。氧代谢的变化 使用免疫组织化学染色，细菌报告菌株，基于微电极的技术， 和宏基因组学。我的研究的潜在影响将是了解氧气的可用性如何影响 肠杆菌科在炎症过程中的生长，并探讨活性氧在其中的作用 过程积极的结果可能为IBD患者的新治疗策略奠定基础。 此外，我所制定的培训计划将帮助我实现成为一名学术研究人员的目标 在一个主要的大学或医院系统。我的导师是塞巴斯蒂安温特博士的专家 炎症过程中宿主-微生物相互作用，我的共同赞助人Vanessa Sperandio博士，的专家 细菌致病机理和基因调控。沿着来自研究生院和职业的支持 发展办公室，温特博士和Sperandio博士将帮助我获得和加强成功所需的技能 在学术研究，包括负责任的行为，技术专长和科学沟通技巧。

Project Summary Patients with Inflammatory Bowel Disease (IBD) experience relapsing and remitting periods of inflammation in their gastrointestinal tract. During periods of inflammation, many patients exhibit an alteration in colonic microbial communities resulting in an increase in facultative anaerobes (primarily members of the Enterobacteriaceae family, such as E. coli). Similar changes in the gut microbiota composition are observed in murine models of colitis. Previous work from our laboratory indicates that the expansion of the Enterobacteriaceae population can be abrogated in part, by inhibiting two of the metabolic pathways utilized by these bacteria to outgrow during inflammation. Inhibition of this Enterobacteriaceae bloom reduced gut inflammation. This finding suggests that microbial dysbiosis aggravates inflammation leading to poorer host outcomes and supports the approach of specifically targeting the microbiota as a means of ameliorating disease. The objective of this study is to further elucidate the metabolic pathways utilized by facultative anaerobes to outgrow during inflammatory conditions. My preliminary data suggest a counterintuitively positive relationship between host-derived reactive oxygen species and the outgrowth of Enterobacteriaceae. I hypothesize that reactive oxygen species allow facultative anaerobic Enterobacteriaceae to respire in the inflamed gut lumen. The specific aims of this proposal are to (1) determine the contribution of host-derived reactive oxygen species in the outgrowth of E. coli in murine models of colitis and (2) determine the mechanistic relationship between cytochrome bd-II oxidase (AppBC) and reactive oxygen species in vitro. To test my hypotheses, I will use a strategic combination of host and bacterial genetics in both chemically-induced and genetic models of colitis. Changes in oxygen metabolism will be characterized using immunohistochemical staining, bacterial reporter strains, microelectrode-based technology, and metagenomics. The potential impact of my research will be to understand how oxygen availability influences Enterobacteriaceae outgrowth during inflammation and explore the role reactive oxygen species play in this process. A positive outcome may lay the foundation for novel treatment strategies for IBD patients. Additionally, the training plan I have laid out will help me achieve my goal of becoming an academic researcher at a major university or hospital system. I will be mentored by my Spnosor Sebastian Winter, Ph.D., an expert in host-microbe interactions during inflammation, and by my Co-Sponsor Vanessa Sperandio, Ph.D., an expert in bacterial pathogenesis and gene regulation. Along with support from the Graduate School and Career Development Office, Dr. Winter and Dr. Sperandio will help me attain and strengthen skills necessary for success in academic research, including responsible conduct, technical expertise, and scientific communication skills.