ROS responses during Vibrio cholerae infection

 描述（由申请方提供）：霍乱弧菌是一种人类病原体，可在宿主小肠定植，导致一种称为霍乱的严重肠道疾病的发作。在 霍乱弧菌要在宿主体内成功定殖，必须表达一系列毒力因子，这些毒力因子一直是霍乱研究的重点。然而，细菌的致病性是体内的多因素特性，其涉及宿主对感染的反应和细菌微生物组对定殖的干扰。例如，尽管霍乱的病理学不是免疫驱动的，但已经表明，霍乱患者和实验动物模型中轻微但显著的炎症反应是由霍乱弧菌感染诱导的，并且可能在疾病的解决中发挥作用。关于霍乱弧菌如何诱导炎症以及霍乱弧菌如何应对这些信号并帮助其定植，人们知之甚少。在这里，我们对没有霍乱弧菌的小鼠肠道和被感染的小鼠肠道进行了RNAseq分析，以确定宿主对霍乱弧菌感染的反应。参与活性氧（ROS）产生的一个基因Duox 2（编码NADPH氧化酶）被强烈上调，该基因已被证明对控制肠道植物群的生长至关重要。我们表明，在组织培养模型和小鼠中，Duox 2表达和ROS产生都由霍乱弧菌诱导。有趣的是，这种诱导依赖于霍乱弧菌毒力基因的表达。此外，我们的初步研究表明，霍乱患者粪便样品中的霍乱弧菌细胞对ROS具有高度抗性，表明霍乱弧菌在感染过程中经历了ROS抗性的诱导。为了阐明霍乱弧菌如何克服宿主产生的ROS，我们进行了Tn-seq实验，发现了一组体内ROS抗性所需的霍乱弧菌基因。再加上蛋白质组学的方法，我们揭示了新的转录和翻译后调节机制，参与调节ROS抗性。因此，我们假设在感染期间，霍乱弧菌诱导宿主Duox 2表达，从而产生ROS，这通过调节肠道植物群组成来促进霍乱弧菌定殖，而转录和翻译后调节途径导致霍乱弧菌在体内固有地对ROS具有抗性。我们将研究霍乱弧菌诱导宿主ROS产生的机制及其对肠道微生物群组成和霍乱弧菌定殖的影响。我们将研究成年小鼠模型感染期间霍乱弧菌ROS的抗性。我们将着重于ROS抗性的细胞功能的转录调控和翻译后修饰。最后，我们将通过对直接来自霍乱患者呕吐物和粪便的霍乱弧菌细胞进行RNAseq和蛋白质组学分析来研究霍乱患者中霍乱弧菌ROS抗性机制。

 DESCRIPTION (provided by applicant): Vibrio cholerae is a human pathogen which colonizes small intestines of host, resulting in the onset of a severe diarrheal disease known as cholera. In order for V. cholerae to successfully colonize 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 property in vivo that involves host response to infection, and gu microbiome interference of colonization. For example, although the pathology of cholera is not immune driven, it has been shown that minor, but significant inflammation responses in cholera patients and in experimental animal models are induced by V. cholerae infection and likely play a role in the resolution of disease. Little is known how inflammation is induced by V. cholerae and how V. cholerae copes with these signals and help its colonization. Here we performed an RNAseq analysis on mouse intestines free of V. cholerae and those that were infected to determine host responses to V. cholerae infection. One gene involved in reactive oxygen species (ROS) production, Duox2, encoding an NADPH oxidase and has been shown to be essential for controlling the growth of gut flora, was strongly upregulated. We show that both Duox2 expression and ROS production are induced by V. cholerae in a tissue culture model and in mice. Interestingly, this induction is dependent on V. cholerae virulence gene expression. Moreover, our preliminary studies indicate that V. cholerae cells in cholera patients' stool samples are highly resistant to ROS, suggesting that V. cholerae undergoes induction of ROS resistance during infection. To elucidate how V. cholerae overcome ROS produced by the host, we performed a Tn-seq experiment and found a set of V. cholerae genes that are required for ROS resistance in vivo. Together with a proteomics approach, we reveal novel transcriptional and posttranslational regulation mechanisms that are involved in regulating ROS resistance. Therefore we hypothesize that during infection, V. cholerae induces host Duox2 expression, thus ROS production, which facilitate V. cholerae colonization by modulating gut flora composition, whereas transcriptional and posttranslational regulatory pathways lead to V. cholerae inherently resistant to ROS in vivo. We will investigate the mechanism of V. cholerae-induced host ROS production and its effects on gut microbiota composition and V. cholerae colonization. We will investigate V. cholerae ROS resistance during infection of an adult mouse model. We will focus on transcriptional regulation and posttranslational modification of cellular functions of ROS resistance. Finally, we will investigate V. cholerae ROS resistance mechanisms in cholera patients by performing RNAseq and proteomic analysis of V. cholerae cells directly from cholera patient vomituses and stools.