Virulence and Adaptation to the Host Environment of Pathogenic Leptospira

摘要：项目2，巴斯德研究所 钩端螺旋体是一种高度异质性的细菌属，而钩端螺旋体是一种普遍存在的自由生活的细菌 环境水和土壤中的腐生植物或可引起播散性感染的病原体，来自 大鼠无症状携带到人和动物的致死性急性感染。尽管最近取得了进展，但 钩端螺旋体属的研究仍然很少，对病原体适应宿主的能力也知之甚少。 并引发疾病。在传播过程中，病原体必须绕过宿主防御机制，适应 不同形式的压力。这项计划项目中提出的工作旨在鉴定和表征细菌 促进哺乳动物宿主适应和使钩端螺旋体建立急性感染的决定因素。在AIM 1、我们将确定疾病严重程度的细菌标志物。具有良好特性的钩端螺旋体基因组测序 我们收集的菌株和项目4(杜克大学)收集的临床分离株将揭示对多样性的新见解。 菌株和物种以及它们的致病性。我们将进行第一次钩端螺旋体属内大规模 进化研究，以确定在进化的不同节点上的阶段性祖先事件 对我们今天所知的病原体的影响，并理解他们可能的贡献 对一些致病物种的生态位适应和增强的毒力。我们将特别 将我们的注意力集中在致病亚类P1中的进化节点上，该亚类分离了感染的物种 人类(P1hv)来自不被描述为人类病原体的物种(P1lv)。推定的毒性因素将是 通过靶向突变或基因沉默使代表性菌株失活，或从 我们的随机转座子突变体库。我们将与科本和哈克实验室合作评估 突变体的表型。我们将对从项目4(杜克大学)收集的样本进行诊断，我们将提供 为实地考察提供技术支持。我们的工作还应有助于识别新的抗原和/或 为诊断这一被忽视的新疾病制定新战略的标志。目标2将 描述适应宿主环境的基因表达的调节。成功的寄主定植 钩端螺旋体感染需要对不断变化的情况做出感知和反应。一种双重的RNA-SEQ方法 急性仓鼠模型将揭示问号钩端螺旋体与宿主相互作用的分子机制。 分析钩端螺旋体体内和体外不同条件下的转录组将增强我们的 病原体如何适应寄主环境以及转录因子所起的作用的知识 全球基因中的过氧化应激调节因子Perra和PerRb以及非编码小RNA等调节因子 表情。我们还将研究表观遗传修饰在全球基因调控和毒力中的作用。 钩端螺旋体。这个项目将增加我们对这种危及生命的病原体生物学的了解 钩端螺旋体病知识的许多空白，最终目的是确定其发病机制 致病性钩端螺旋体感染并适应宿主。

Abstract: Project 2, Institut Pasteur Leptospira is a highly heterogeneous bacterial genus and leptospires are ubiquitous bacteria found as free-living saprophytes in environmental water and soil or as pathogens that can cause disseminated infections, from asymptomatic carriage in rats to lethal acute infection in both humans and animals. Despite recent progress, the genus Leptospira remains understudied, and little is known about the ability of the pathogen to adapt to the host and cause disease. During dissemination, pathogens must circumvent host defense mechanisms and adapt to different forms of stresses. The work proposed in this program project seeks to identify and characterize bacterial determinants that promote mammalian host adaptation and enable leptospires to establish acute infection. In Aim 1, we will identify bacterial markers of disease severity. Genome sequencing of well-characterized Leptospira strains from our collection and clinical isolates collected in project 4 (Duke) will reveal new insights on the diversity of strains and species and their pathogenicity. We will perform the first Leptospira intra-genus large-scale evolutionary study to identify stepwise ancestral events at different nodes of evolution that have drastic consequences on the pathogens as we know them today and understand what could have been their contribution to the ecological niche adaptation and enhanced virulence of some of the pathogenic species. We will particularly focus our attention on the node of evolution in the pathogenic subclade P1 that separated the species infecting humans (P1hv) from the species not described as human pathogens (P1lv). The putative virulence factors will be inactivated in representative strains by targeted mutagenesis or gene silencing, or mutants will be selected from our library of random transposon mutants. We will collaborate with the Coburn and Haake labs to assess phenotypes of mutants. We will perform diagnosis for samples collected from project 4 (Duke) and we will provide technical support for field studies. Our work should also contribute to the identification of new antigens and/or markers for the development of novel strategies for the diagnosis of this neglected emerging disease. Aim 2 will characterize the regulation of gene expression in adaptation to the host environment. Successful host colonization by Leptospira requires sensing and response to face of changing conditions. A Dual RNA-seq approach in the acute hamster model will reveal the molecular mechanisms of interactions between L. interrogans and its host. Analysis of the transcriptome of Leptospira strains in vivo and different in vitro conditions will enhance our knowledge of how the pathogen can adapt to the host environment and the roles played by transcriptional regulators such as the Peroxide Stress Regulators PerRA and PerRB and non-coding small RNA in global gene expression. We will also investigate the role of epigenetic modification in global gene regulation and virulence in Leptospira. This project will increase our understanding of the biology of this life-threatening pathogen to fill out the many gaps in leptospirosis knowledge with the ultimate goal of identifying the mechanisms by which pathogenic Leptospira infect and adapt the host.