Vibrio cholerae antinitrosative stress defenses and gut microbiome interaction

项目摘要 人类病原体霍乱弧菌是被称为霍乱的严重腹泻病的病原体， 每年影响全球数百万人为了使霍乱弧菌能够成功地在 宿主的小肠必须表达一系列毒力因子，这些毒力因子一直是宿主的主要关注点。 霍乱研究然而，细菌的致病性是一个多因素的过程，不仅取决于 对毒力因子表达的影响，但宿主对感染的反应以及与宿主微生物的相互作用 肠道的微生物组。霍乱弧菌必须克服宿主产生的一组主要因素 包括一氧化氮（NO）和NO衍生的氮氧化物和二亚硝基铁络合物， 亚硝化胁迫（reactive nitrosative stress，RNS）。先前的研究表明，诱导型一氧化氮 一氧化氮合酶（iNOS或NOS 2），合成NO的酶，是其中上调最多的蛋白质， 我们的研究结果表明，在霍乱期间， 感染成年小鼠模型，且在iNOS-/-小鼠或经处理小鼠中，霍乱弧菌定殖减少 iNOS抑制剂氨基胍（AG）。然而，很少有人知道如何增加RNS在体内 影响霍乱弧菌、肠道微生物组和微生物间的相互作用， 感染我们推测，感染过程中诱导的RNS产生调节了细胞的结构、功能， 肠道微生物组的病原体相互作用，使霍乱弧菌相对于细菌具有竞争优势 这是由于与毒力因子表达一起受到严格调控的几种RNS抗性机制。 我们将从两个方面来检验这一假说。在目标1中，我们将阐明霍乱弧菌对RNS的反应 以及这些反应如何与毒力一起调节。在目标2中，我们将检查 RNS在调节肠道微生物组中的作用，RNS依赖性变化如何影响霍乱弧菌 易感性，以及RNS如何影响这种病原体和肠道之间的特定微生物相互作用 微生物

PROJECT SUMMARY The human pathogen Vibrio cholerae is the etiologic agent of the severe diarrheal disease known as cholera, which affects millions of people annually, worldwide. In order for V. cholerae to successfully colonize in the small intestines of the host, it must express a series of virulence factors, which have been the main focus of the cholera research. However, bacterial pathogenicity is a multifactorial process in vivo that depends not only on virulence factor expression, but host responses to infection and interactions with the commensal microbes of the gut, the gut microbiome. One major set of host-produced factors that must be overcome by V. cholerae comprises nitric oxide (NO) and NO-derived nitrogen oxides and dinitrosyl-iron complexes, collectively known as nitrosative stress (reactive nitrogen species, RNS). Previous studies show that inducible nitric oxide synthase (iNOS or NOS2), the enzyme that synthesizes NO, is among the most upregulated proteins in duodenal tissue during cholera, and our results show both that iNOS is highly induced upon V. cholerae infection of an adult mouse model, and that V. cholerae colonization is reduced in iNOS-/- mice or mice treated with the iNOS inhibitor aminoguanidine (AG). However, little is known about how increased RNS in vivo impacts V. cholerae, the gut microbiome, and the inter-microbial interactions that drive the ultimate outcome of infection. We hypothesize that RNS production induced during infection modulates the structure, function, and pathogen interactions of the gut microbiome, granting V. cholerae a competitive advantage over commensals due to several RNS-resistance mechanisms that are tightly regulated alongside virulence factor expression. We will examine this hypothesis in two aims. In Aim 1, we will elucidate how V. cholerae responds to RNS during infection, and how these responses are regulated alongside virulence. In Aim 2, we will examine the role of RNS in modulating the gut microbiome, how RNS-dependent changes influences V. cholerae susceptibility, and how RNS affects specific microbial interactions between this pathogen and commensal gut microbes.