Type VI Protein Secretion in an Emerging Multidrug-Resistant Pathogen

新兴多重耐药病原体中的 VI 型蛋白分泌

• 批准号: 8254576
• 负责人: Edward Geisinger
• 金额: $ 5.39万
• 依托单位: TUFTS UNIVERSITY BOSTON
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-03 至 2015-07-02
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8254576
• 关键词: Acinetobacter; Acinetobacter baumannii; Address; Adherence; Adhesions; Animal Model; Anti-Infective Agents; Antibiotic Resistance; Bacteria; Cell Culture Techniques; Cell physiology; Cells; Clinical; Communicable Diseases; Disease; Drug resistance; Educational process of instructing; Environment; Epidemic; Epithelial; Epithelial Cells; Goals; Growth; Human; Immune; Immune response; Immunity; In Vitro; Infection; Inflammation; Knowledge; Legionella pneumophila; Lesion; Mammalian Cell; Measures; Microbe; Modeling; Molecular Biology; Morbidity - disease rate; Multi-Drug Resistance; Mus; Nosocomial Infections; Pasteurella pseudotuberculosis; Pathogenesis; Pathogenicity; Pathology; Patients; Play; Pneumonia; Protein Secretion; Protein translocation; Proteins; Reporter; Research; Resistance; Role; Sepsis; Specificity; System; Techniques; Testing; Therapeutic; Tissues; Toxic effect; Training; Vaccines; Virulence; Work; clinical phenotype; cytotoxicity; drug resistant bacteria; experience; genome wide association study; immunoregulation; mortality; mouse model; mutant; new therapeutic target; novel; pathogen; prevent; research study

DESCRIPTION (provided by applicant): Hospital-acquired infections due to multidrug-resistant bacteria are a major cause of increased morbidity and mortality in patients with weakened immunity. A leading agent of such infections is the bacterium Acinetobacter baumannii. This microbe causes invasive infections, including pneumonia and sepsis, that in recent years have become increasingly severe and antibiotic-resistant, raising the specter that they may one day be untreatable. New ways to prevent and treat infections with A. baumannii are urgently needed, but alarmingly little is known about how these bacteria cause disease. Recent evidence indicates that these bacteria induce adherence-dependent cytotoxicity toward cultured epithelial cells; however, the mechanisms used by A. baumannii to intoxicate cells upon adhesion are unclear. The goal of the proposed studies is to understand how these microbes interact with human cells and how such interactions undermine normal cellular processes, promoting infection. Towards this goal, this proposal aims to characterize in detail a contact-dependent protein delivery system, known as a Type VI Secretion System (T6SS) that is present in clinical strains of A. baumannii responsible for recent epidemics. These systems play a role in host infections by a range of microbes, but the system is undefined in A. baumannii. The proposed work will determine which cells are targeted by the A. baumannii T6SS, identify the effector proteins it sends into these cells, and examine the functional roles of the system and its effectors in host interactions and pathogenesis. These aims will be accomplished by analyzing the transfer of reporter fusions into target cells, conducting directed genome-wide screens for effectors, and examining the effects of T6SS- and effector-null mutants on bacterial toxicity and the host innate immune response during interactions with host cells in culture and in a murine model of pneumonia. These studies will break new ground on the mechanisms used by A. baumannii to promote infection and will address key gaps in our understanding of T6SS pathobiology. Ultimately, this information will uncover targets for novel anti-infective treatments and vaccines against highly drug- resistant bacteria. The training experience will broaden my expertise in molecular biology, teach me new techniques in mammalian cell culture and animal models, and advance my understanding of the pathogenesis of infectious diseases. PUBLIC HEALTH RELEVANCE: Acinetobacter baumannii, a frequent cause of invasive, hospital-acquired infections, has become more drug resistant and aggressive in recent years. The proposed research is aimed at understanding how the bacterium interacts with cells within the infected host in a way that promotes bacterial growth and misregulation of host cells. This knowledge will expose potential targets for novel anti-infective therapeutics against these highly resistant microbes.!

描述（由申请人提供）：由于多药耐药性细菌引起的医院获得感染是免疫力较弱的患者发病率和死亡率增加的主要原因。这种感染的主要药物是细菌鲍曼尼菌细菌。这种微生物会引起侵入性感染，包括肺炎和败血症，近年来已经变得越来越严重和抗生素耐药性，从而提高了幽灵，即可能有一天无法治疗。迫切需要预防和治疗鲍曼尼曲霉感染的新方法，但令人震惊的是，这些细菌如何引起疾病。最近的证据表明，这些细菌诱导依赖性细胞毒性对培养的上皮细胞。然而，鲍曼尼曲霉在粘附后用来醉酒细胞的机制尚不清楚。拟议的研究的目的是了解这些微生物如何与人类细胞相互作用，以及这种相互作用如何破坏正常的细胞过程，从而促进感染。为了实现这一目标，该提案旨在详细描述接触依赖性的蛋白质递送系统，该系统被称为VI型分泌系统（T6SS），该系统存在于鲍曼尼（A. baumannii）的临床菌株中，负责最近的流行病。这些系统在一系列微生物中在宿主感染中发挥作用，但是该系统在鲍曼尼（A. Baumannii）中不确定。拟议的工作将确定哪些细胞是由鲍曼曼曲霉T6S靶向的，识别其发送到这些细胞中的效应蛋白，并检查系统及其在宿主相互作用和发病机理中的功能作用。这些目标将通过分析报告基因融合到靶细胞中的转移，对效应子进行定向全基因组筛查，并检查T6SS和效应子 - 无突变体对细菌毒性的影响，并在与宿主互动期间与宿主与宿主的固有免疫反应进行。培养和肺炎鼠模型中的细胞。这些研究将介绍鲍曼尼曲霉所用的机制来促进感染，并将解决我们对T6SS病理生物学理解的关键差距。最终，这些信息将发现新型抗感染治疗的目标 和针对高度耐药细菌的疫苗。培训经验将扩大我在分子生物学方面的专业知识，教我哺乳动物细胞培养和动物模型的新技术，并促进我对感染性疾病发病机理的理解。 公共卫生相关性：鲍曼尼（Baumannii）经常引起侵入性，医院获得感染的原因，近年来已经变得更具耐药性和侵略性。提出的研究旨在了解细菌如何与受感染宿主中细胞相互作用，从而促进细菌生长和宿主细胞的不正当。这些知识将暴露针对这些高度抗性微生物的新型抗感染治疗剂的潜在靶标。