Bacterial responses to reactive chlorine stress and their role in host-microbe interactions

项目摘要/摘要 细菌和免疫系统之间的接口对人类健康是绝对基础的，而 我工作的长期目标是了解这种接口是如何受到监管的。两者对肠道的侵袭 病原菌和共生菌对人类健康有重大影响。肠道微生物群落是 受肠道氧化还原环境和先天免疫产生的氧化剂的强烈影响 系统在炎症过程中。这些物质包括活性氧物种(ROS)和活性氯物种 (RCS)。RCS，包括次氯酸(HOCl)和反应性氯胺，是强大的抗菌剂 氧化剂能够破坏许多细胞成分，包括蛋白质、脂类、辅因子和DNA。高氯酸盐 是医疗、工业和家庭环境中非常常见的消毒剂，但RCS也是 中性粒细胞的抗菌库，在炎症期间积累，似乎对控制很重要 粘膜上皮的细菌定植，如肠道内的。关于这种细菌是如何 它们构成了人类微生物组对RCS的感觉或反应，而这种反应预计是关键的 细菌在与人类免疫系统的互动中存活下来的能力。这项研究中提出的 应用程序将使用转录、遗传、生化和系统生物学技术来识别和 描述细菌用来感知和响应RCS的基因、蛋白质和途径，并将使用 哺乳动物细胞培养和动物研究，以测试这些机制在宿主-微生物相互作用中的作用。 我们的短期到中期目标集中在肠道微生物大肠杆菌和雷氏乳杆菌上。大肠杆菌是 生理特性很好，易于操作，促炎，而路氏乳杆菌具有抗炎作用。 炎症性疾病，与健康的微生物群有关。我们将识别和表征RCS传感 这些生物体中的调节器，并描述这些调节器和 它们控制的基因保护细菌免受RCS介导的损伤，并影响 细菌和它们的哺乳动物宿主。从长远来看，这些研究将扩展到其他模型。 细菌，以表征微生物组的RCS反应的多样性。的最终目标是 这项研究是为了了解医学上重要的细菌的RCS应激反应，特别是关注 它们在定植和致病中所起的作用。这项研究计划的结果将推动 氧化应激反应领域，阐明RCS感应转录体内特异性的基础 因素，有助于理解RCS毒性的潜在原因，并可能导致识别新的 细菌与天然免疫系统相互作用的机制。这可能会导致新的 微生物靶向治疗越来越多的已知受 微生物组，并可能对我们理解宿主-微生物相互作用有广泛的影响， 在多种生物中的致病机制、定植和RCS耐受性。

Project Summary/Abstract The interface between bacteria and the immune system is absolutely fundamental to human health, and the long-term goal of my work is to understand how that interface is regulated. Colonization of the gut by both pathogenic and commensal bacteria has major effects on human health. Gut microbial communities are strongly affected by the redox environment of the intestine and by oxidants produced by the innate immune system during inflammation. These include both reactive oxygen species (ROS) and reactive chlorine species (RCS). RCS, including hypochlorous acid (HOCl) and reactive chloramines, are powerful antimicrobial oxidants capable of damaging many cellular components, including proteins, lipids, cofactors, and DNA. HOCl is a very common disinfectant in medical, industrial, and home settings, but RCS are also a natural part of the antimicrobial arsenal of neutrophils, accumulate during inflammation, and appear to be important for controlling bacterial colonization of mucosal epithelia, such as those in the gut. Little is known about how the bacteria which make up the human microbiome sense or respond to RCS, and this response is expected to be critical for the ability of bacteria to survive interactions with the human immune system. The research proposed in this application will use transcriptomic, genetic, biochemical, and systems biology techniques to identify and characterize the genes, proteins, and pathways which bacteria use to sense and respond to RCS, and will use mammalian cell culture and animal studies to test the roles of these mechanisms in host-microbe interactions. Our short- to medium-term goals focus on the gut microbes Escherichia coli and Lactobacillus reuteri. E. coli is physiologically very well characterized, easy to manipulate, and pro-inflammatory, while L. reuteri is anti- inflammatory and associated with a healthy microbiome. We will identify and characterize RCS-sensing regulators in these organisms and characterize the molecular mechanisms by which those regulators and the genes they control protect the bacteria against RCS-mediated damage and influence interactions between bacteria and their mammalian hosts. In the longer-term, these studies will be expanded to other model bacteria in order to characterize RCS responses across the diversity of the microbiome. The ultimate goal of this research is to understand RCS stress responses in medically important bacteria, particularly focusing on the roles they play in colonization and pathogenesis. The results of this research program will advance the field of oxidative stress response, elucidate the basis for the in vivo specificity of RCS-sensing transcription factors, help understand the underlying causes of RCS toxicity, and may lead to identification of novel mechanisms of interaction between bacteria and the innate immune system. This could potentially lead to new microbe-targeted treatments for the growing list of inflammatory diseases known to be influenced by the microbiome, and may have broad implications for our understanding of host-microbe interactions, pathogenesis, colonization, and RCS tolerance in a wide variety of organisms.