Shifts in the Gastrointestinal Metabolome During Clostridium difficile Infection

艰难梭菌感染期间胃肠道代谢组的变化

• 批准号: 8744297
• 负责人: Casey Michelle Theriot
• 金额: $ 6.45万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-30 至 2015-06-19
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8744297
• 关键词: Address; Affect; Amino Acids; Antibiotic Therapy; Antibiotic-Associated Colitis; Antibiotics; Bile Acids; Bioinformatics; Biological; Biological Markers; Carbohydrates; Clostridium difficile; Communicable Diseases; Communities; Complex; Core Facility; Data; Data Analyses; Development; Dipeptides; Disease; Educational workshop; Ensure; Environment; Equipment; Ethics; Future; Gastrointestinal Diseases; Gastrointestinal tract structure; Germination; Goals; Grant; Growth; Health; Health Care Costs; Human; In Vitro; Indigenous; Infection; Intestines; Knowledge; Lead; Learning; Mass Spectrum Analysis; Mediating; Medicine; Mentors; Mentorship; Metabolic; Methodology; Methods; Mission; Morbidity - disease rate; Mus; Nonesterified Fatty Acids; Nutrient; Outcome; Pathogenesis; Physiological; Play; Predisposition; Preparation; Process; Production; Public Health; Research; Research Design; Research Personnel; Research Project Grants; Resistance; Resources; Role; Sampling Studies; Scientist; Staging; Techniques; Technology; Testing; Therapeutic; Therapeutic Intervention; Toxin; Training; base; career; gastrointestinal; gut microbiota; improved; innovation; instrument; interest; liquid chromatography mass spectrometry; mass spectrometer; metabolomics; microbiome; mortality; mouse model; novel; prevent; programs; public health relevance; statistics; success

DESCRIPTION (provided by applicant): Clostridium difficile infection (CDI) is the leading cause of antibiotic-associated colitis and is responsible for significant morbidity, mortality and increased healthcare costs. Despite the significance of CDI, there are major gaps in our understanding of the pathogenesis of this infection. Antibiotics disrupt the indigenous gut microbiota, reducing resistance to C. difficile colonization. However, our knowledge of how the gut microbiota confers resistance to CDI is rudimentary, presenting a significant roadblock to improving preventative and therapeutic approaches against this infection. My long-term goal is to understand how the gastrointestinal tract microbiota mediates colonization resistance against C. difficile. The overall objective of this application is to define metabolites associated with changes in the gut microbiota that contribute to C. difficile colonization and pathogenesis. Using an untargeted metabolomics approach, we have shown that the intestinal environment of antibiotic-treated mice was characterized by major shifts in metabolic profiles. Following antibiotic administration, we detected increases in primary bile acids, carbohydrates, and amino acids and decreased free fatty acids, secondary bile acids and dipeptides; reflecting the diminished metabolic activity of the gut microbiome. Subsequently, we demonstrated that C. difficile could utilize many of these metabolites for in vitro germination and growth. The central hypothesis is that the availability of specific nutrients that support C. difficile growth in the gt after antibiotic treatment is responsible for the observed decrease in colonization resistance. The rationale for the proposed research is that understanding the role the gastrointestinal metabolome plays in C. difficile pathogenesis has the potential to improve preventative and therapeutic approaches for this infection. Guided by strong preliminary data, this hypothesis will be tested by pursuing two specific aims: 1) Identify metabolites in the gastrointestinal tract that contribute to C. difficile colonization and pathogenesis; and 2) Determine the physiological concentrations of gut metabolites that modulate C. difficile pathogenesis. Under the first specific aim, we will use an untargeted metabolomics approach to identify candidate biomarkers from the murine gastrointestinal tract prior to CDI and during different stages of infection. Under the second specific aim, we will use a targeted metabolomics approach to confirm and quantitate metabolites that were significantly affected in specific aim 1, prior to CDI and during different stages of infection. We will also use in vitro studies to confirm their role in C. difficile germination, growth and toxin production. The approach is innovative, because we are using new mass spectrometry technology in a different way, to help solve important biological questions that will improve public health. The proposed research is significant, because it will lead to the identification of novel biomarkers and potential targets for therapeutic interventions to prevent or treat CDI. My overall career goal is to establish an independent research career bridging the field of metabolomics and biomedical infectious diseases, with emphasis on understanding Clostridium difficile pathogenesis. My long-term research interests have always included studying the impact of disease and how it impacts human health. With the advent of "omics" technologies complex communities, including the gastrointestinal tract, can be defined. The expertise and co-mentorship of both Dr. Vincent Young and Dr. Charles Burant ensures success of this research project and my continued success a research scientist. The combined resources that my mentors and collaborators share will allow me access to mouse models of C. difficile infection and the Metabolomics Core Facility, which includes access to state of the art mass spectrometry equipment and trained experts in metabolomics. Finally, these studies will provide me with the opportunity to learn the methodologies related to the emerging field of metabolomic profiling, including the design of studies, sample preparation, metabolite extraction and analysis by the latest mass spectrometer based methods and the processes of data analysis and bioinformatics interpretation of the acquired data. The mentorship plan detailed in this proposal and further didactic coursework in ethics, bioinformatics, statistics, and workshops on metabolomics will help me to become an independent researcher in the field of biomedical infectious diseases and metabolomics.

描述（由申请方提供）：艰难梭菌感染（CDI）是结肠炎相关性结肠炎的主要原因，并导致显著的发病率、死亡率和医疗费用增加。尽管CDI的重要性，我们对这种感染的发病机制的理解存在重大差距。抗生素破坏了固有的肠道微生物群，降低了对C。艰难的殖民然而，我们对肠道微生物群如何赋予对CDI的抵抗力的了解是基本的，这对改善针对这种感染的预防和治疗方法构成了重大障碍。我的长期目标是了解胃肠道微生物群如何介导对C的定植抵抗。很难本申请的总体目标是定义与肠道微生物群变化相关的代谢物，这些代谢物有助于C。艰难的定植和发病机制。使用非靶向代谢组学方法，我们已经表明，经禁食处理的小鼠的肠道环境的特征在于代谢谱的重大变化。抗生素给药后，我们检测到初级胆汁酸、碳水化合物和氨基酸增加，游离脂肪酸、次级胆汁酸和二肽减少;反映了肠道微生物组的代谢活性降低。随后，我们证明了C。艰难梭菌可以利用这些代谢物中的许多用于体外萌发和生长。中心假设是支持C.抗生素治疗后GT中艰难梭菌的生长是观察到的定植抗性降低的原因。这项研究的基本原理是，了解胃肠道代谢组在C。difficile发病机制的研究有可能改善这种感染的预防和治疗方法。在强有力的初步数据的指导下，将通过追求两个具体目标来测试该假设：1）鉴定胃肠道中的代谢物， 有助于C。艰难梭菌定植和发病机制;和2）确定调节C.难治性发病机制根据第一个具体 我们将使用非靶向代谢组学方法，在CDI之前和感染的不同阶段，从小鼠胃肠道中鉴定候选生物标志物。在第二个具体目标下，我们将使用靶向代谢组学方法来确认和定量在CDI之前和感染的不同阶段期间在具体目标1中受到显著影响的代谢物。我们还将使用体外研究来证实它们在C.艰难萌发、生长和毒素产生。这种方法是创新的，因为我们正在以不同的方式使用新的质谱技术，以帮助解决重要的生物学问题，从而改善公众健康。这项拟议的研究意义重大，因为它将导致识别新的生物标志物和潜在的治疗干预目标，以预防或治疗CDI。 我的总体职业目标是建立一个独立的研究事业，桥接代谢组学和生物医学传染病领域，重点是了解艰难梭菌的发病机制。我的长期研究兴趣一直包括研究疾病的影响以及它如何影响人类健康。随着“组学”技术的出现，可以定义包括胃肠道在内的复杂社区。Vincent Young博士和Charles Burant博士的专业知识和共同指导确保了这个研究项目的成功，以及我作为研究科学家的持续成功。我的导师和合作者共享的综合资源将使我能够访问C语言的小鼠模型。艰难梭菌感染和代谢组学核心设施，其中包括获得最先进的质谱设备和训练有素的代谢组学专家。最后，这些研究将使我有机会学习与代谢组学分析的新兴领域相关的方法，包括研究设计，样品制备，代谢物提取和最新的基于质谱仪的方法分析以及数据分析和生物信息学对所获得数据的解释。本建议书中详细介绍的导师计划以及伦理学，生物信息学，统计学和代谢组学研讨会的进一步教学课程将帮助我成为生物医学传染病和代谢组学领域的独立研究人员。