Virulence and Adaptation to the Host Environment of Pathogenic Leptospira

致病性钩端螺旋体的毒力及其对宿主环境的适应

• 批准号: 10643291
• 负责人: Mathieu Picardeau
• 金额: $ 16.61万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-16 至 2028-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10643291
• 关键词: Acute; Amphibia; Animal Model; Animals; Antigens; Attention; Bacteria; Biology; Birds; Classification; Classification Scheme; Clinical; Collaborations; Collection; Complex; Data; Defense Mechanisms; Development; Diagnosis; Disease; Disease Marker; Dose; Environment; Epigenetic Process; Event; Evolution; Face; Gene Expression Regulation; Gene Silencing; Genes; Genetic; Genetic Transcription; Genome; Goals; Hamsters; Host Defense Mechanism; Human; In Vitro; Infection; Knowledge; Laboratories; Leptospira; Leptospira interrogans; Leptospirosis; Libraries; Life; Mammals; Modeling; Modification; Molecular; Mutagenesis; Mutation; Oxidative Stress; Pathogenicity; Peroxides; Phenotype; Phylogenetic Analysis; Play; Predisposition; Process; Rattus; Regulon; Reptiles; Role; Route; Sampling; Severity of illness; Small RNA; Soil; Stress; Untranslated RNA; Urine; Virulence; Virulence Factors; Virulent; Water; Work; Zoonoses; acute infection; comparative genomics; contaminated water; field study; gain of function; genome sequencing; host colonization; human pathogen; in vivo; insight; loss of function; mutant; neglect; novel strategies; pathogen; programs; response; tool; transcriptome; transcriptome sequencing; transmission process

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.

摘要：Project 2，Institut Pasteur 钩端螺旋体是一种高度异质的细菌属，钩端螺旋体是普遍存在的细菌 环境水和土壤中的腐生植物或可能引起传播感染的病原体 在人和动物中，大鼠无症状的急性急性感染。尽管最近取得了进展，但 钩端螺旋体属仍在研究中，对病原体适应宿主的能力知之甚少 并引起疾病。在传播过程中，病原体必须规避宿主防御机制并适应 不同形式的压力。该计划项目中提出的工作旨在识别和表征细菌 促进哺乳动物宿主适应并能够诱导的决定因素，能够建立急性感染。目标 1，我们将确定疾病严重程度的细菌标志物。特征性钩端螺旋体的基因组测序 我们收集的收藏和临床分离株（杜克大学）收集的临床分离株的压力将揭示有关多样性的新见解 菌株和物种及其致病性。我们将执行大规模的第一个钩端螺旋体内部 进化研究以识别具有剧烈进化节点的逐步祖先事件 我们今天对病原体的影响，并了解他们的贡献可能是什么 对某些致病物种的生态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子基P1中的进化节点上，该p1分离了感染物种 该物种的人类（P1HV）不被描述为人类病原体（P1LV）。推定的毒力因素将是 通过靶向诱变或基因沉默在代表性菌株中灭活，或从中选择突变体 我们的随机转座子突变体库。我们将与Coburn和Haake Labs合作评估 突变体的表型。我们将对项目4（杜克）收集的样本进行诊断，我们将提供 对现场研究的技术支持。我们的工作还应有助于识别新抗原和/或 制定新策略以诊断这种被忽视的新兴疾病的标志。 AIM 2意志 表征适应宿主环境中基因表达的调节。成功的宿主殖民化 通过钩端螺旋体，需要感知和对面对不断变化的条件的反应。在 急性仓鼠模型将揭示L. Excentogans及其宿主之间相互作用的分子机制。 分析体内钩端螺旋体菌株的转录组和不同体外条件的分析将增强我们的 了解病原体如何适应宿主环境以及转录扮演的角色 在全球基因中，诸如过氧化物应力调节剂Perra和Perrb和非编码小RNA之类的调节剂 表达。我们还将研究表观遗传修饰在全球基因调节和毒力中的作用 钩端螺旋体。该项目将提高我们对这种威胁生命的病原体生物学的理解，以填写 钩端螺旋体病知识中的许多差距，其最终目标是确定该机制 致病性钩端螺旋体感染并适应宿主。