Mechanisms of SFG Rickettsia-Host Interactions

SFG 立克次体与宿主相互作用的机制

基本信息

批准号：
10293664
负责人：
REBECCA L LAMASON
金额：
$ 55.82万
依托单位：
MASSACHUSETTS INSTITUTE OF TECHNOLOGY
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-08-12 至 2025-07-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10293664
关键词：
Ankyrin Repeat Bacterial Infections Bacterial Proteins Biochemical Biological Biological Assay Biology Cell Adhesion Molecules Cell physiology Cell-Cell Adhesion Cells Cellular biology Cessation of life Complement Complex Cytosol Development Diagnostic Ectopic Expression Exanthema Future Genes Genetic Genetic Variation Genetic study Goals Human Impairment Infection Integration Host Factors Intercellular Junctions Invaded Label Laboratories Lead Life Life Cycle Stages Location Mediating Metabolic Microscopy Modeling Modernization Molecular Mutagenesis Pathogenesis Pathogenicity Pathway interactions Phase Plasmids Property Proteins Proteomics Research Rickettsia Rickettsia Infections Rickettsia parkeri Site Structure System Techniques Testing Therapeutic Intervention Tick-Borne Diseases Tick-Borne Infections Time Type IV Secretion System Pathway United States National Institutes of Health Vascular Diseases Vinculin Widespread Disease Work base combat design forward genetics genetic approach genetic manipulation improved insight interest member mutant pathogen pathogenic bacteria prevent spotted fever targeted treatment therapeutic target tick-borne tool

项目摘要

PROJECT SUMMARY/ABSTRACT A subset of emerging, but poorly characterized tickborne diseases in the U.S. are caused by Spotted Fever Group (SFG) Rickettsia. These obligate intracellular bacterial pathogens cause mild-to-life-threatening vascular diseases in humans and have a limited set of diagnostics and therapeutic interventions. To promote widespread disease, SFG Rickettsia species have evolved dynamic strategies to invade host cells, escape into the cytosol, and spread from cell to cell. We hypothesize that SFG Rickettsia coordinate their complex life cycle by delivering an arsenal of secreted bacterial proteins (i.e., effectors) that reprogram host cell processes. Unfortunately, the identity and host targets of these secreted effectors have remained largely unknown. Furthermore, direct analysis of the secretion systems and putative effectors have been hampered due to challenges in growing and genetically manipulating these pathogens in the lab. To overcome this barrier, we recently adapted forward genetics and plasmid-based complementation to the model SFG member Rickettsia parkeri, allowing for powerful functional-genetic studies of SFG Rickettsia pathogenesis. Using these tools, we discovered that the secreted effector Sca4 promotes a late stage of cell-to-cell spread by manipulating host cell-cell adhesion. Additionally, transposon mutagenesis of a secreted effector of unknown function (RARP-1) and a component of the anomalous Rickettsia Type 4 secretion system (VirB6e) impairs distinct stages of R. parkeri infection. This proposal will leverage these key advances to examine how a secretion system and secreted effectors promote different steps of the R. parkeri infectious life cycle. Here, we combine our functional-genetic strategies and expertise in host cell biology, with modern biochemical techniques to reveal critical, mechanistic insights into SFG Rickettsia pathogenesis. In Aim 1, we will examine the function and secretome of the T4SS component VirB6e. In Aim 2, we will determine how the secreted effector RARP-1 promotes R. parkeri infection. In Aim 3, we will elucidate how Sca4 specifically targets host cell-cell adhesion complexes during R. parkeri cell-to-cell spread. Collectively, the proposed research will dramatically improve our fundamental understanding of Rickettsia biology and Rickettsia-host interactions and reveal therapeutic targets to prevent or treat tickborne diseases.

项目摘要/摘要在美国的一部分新兴但特征性较差的是滴答疾病是由发烧引起的小组（SFG）立克西亚。这些义务细胞内细菌病原体会导致轻度威胁生命的血管人类的疾病，诊断和治疗干预措施有限。促进广泛疾病，SFG人力素物种具有进化的动态策略来侵入宿主细胞，逃脱到细胞质中，并从细胞传播到细胞。我们假设SFG人力车通过交付来协调其复杂的生命周期重新编程宿主细胞过程的分泌细菌蛋白（即效应子）的砷。不幸的是，这些分泌效应子的身份和宿主目标在很大程度上尚不清楚。此外，直接分析由于增长和在实验室中遗传操纵这些病原体。为了克服这个障碍，我们最近改编了 SFG成员Rickettsia Parkeri的遗传学和基于质粒的互补，允许 SFG人力素病发病机理的强大功能遗传学研究。使用这些工具，我们发现分泌的效应子SCA4通过操纵宿主细胞 - 细胞粘附而促进了细胞对细胞扩散的后期。另外，未知功能（RARP-1）的分泌效应子的转座子诱变和一个成分异常的立克四型分泌系统（VIRB6E）损害了R. parkeri感染的不同阶段。这提案将利用这些关键进步来研究分泌系统和分泌效应子如何促进 R. Parkeri感染生命周期的不同步骤。在这里，我们结合了我们的功能遗传策略和宿主细胞生物学方面的专业知识，采用现代化的生化技术来揭示关键的机械见解 SFG人力素的发病机理。在AIM 1中，我们将检查T4SS组件的功能和分泌物 VirB6e。在AIM 2中，我们将确定分泌的效应子RARP-1如何促进R. parkeri感染。在AIM 3中，我们将阐明SCA4在R. parkeri细胞到细胞期间如何专门针对宿主细胞细胞粘附复合物传播。总的来说，拟议的研究将极大地改善我们对人力车生物学和人力车互动，并揭示治疗靶标，以预防或治疗滴答作用疾病。