Function and Secretion of Bordetella Filamentous Hemagglutinin

博德特氏菌丝状血凝素的功能和分泌

基本信息

批准号：
8245274
负责人：
Peggy A Cotter
金额：
$ 37万
依托单位：
UNIV OF NORTH CAROLINA CHAPEL HILL
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-12-01 至 2016-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8245274
关键词：
Acellular Vaccines Adolescent Adult Affect Amino Acids Bacteria Biochemical Biological Bordetella Bordetella Infections Bordetella bronchiseptica Bordetella pertussis C-terminal Cell Culture Techniques Cell surface Cells Cessation of life Child Complex Data Developed Countries Development Epithelial Epithelial Cells Family Gene Expression Regulation Hemagglutinin Human Immunity In Vitro Incidence Infection Inflammation Inflammatory Inflammatory Response Investigation Lower respiratory tract structure Lung Lung Inflammation Mammals Measures Mediating Membrane Modeling Molecular Genetics Mus Oryctolagus cuniculus Pathogenesis Pathway interactions Pertussis Pertussis Vaccine Play Production Proteins Public Health Rattus Receptor Cell Recruitment Activity Respiratory System Respiratory Tract Infections Respiratory tract structure Role Site Surface Testing Trachea United States Vaccinated Vaccination Vaccines Virulence Virulence Factors base chemokine comparative cytokine global health improved insight macrophage member mutant novel pathogen protein folding receptor receptor binding research study response young adult

项目摘要

DESCRIPTION (provided by applicant): Pertussis (also known as whooping cough) continues to be a global health problem with an estimated 45 million cases annually and 300,00 deaths, which occur mostly in children. Despite high vaccine coverage, incidence has been increasing in several developed countries since the 1990s, due apparently to waning immunity in adolescents and young adults who were vaccinated, rather than infected, as children, especially those vaccinated with acellular vaccines. Understanding how vaccine components function in pathogenesis and immunity is critical to the development of improved vaccines. The causative agents of pertussis are Bordetella pertussis and Bordetella parapertussishu. These strictly human-specific pathogens are extremely closely related to Bordetella bronchiseptica, which has a broad host range that includes nearly all mammals. We have been taking a comparative approach, including all three of these Bordetella subspecies to study the roles of virulence gene regulation and of specific virulence factors in pathogenesis. Using B. bronchiseptica allows us to study respiratory infection in the lab in the context of a natural bacterial-host interaction, and the use of chimeric B. bronchiseptica and B. pertussis strains that express heterologous virulence factors has allowed us to demonstrate that several virulence factors, including Filamentous hemagglutinin (FHA), are functionally interchangeable between these subspecies. FHA is a large surface-associated and secreted protein and one of the primary components of pertussis vaccines. We have shown that FHA is required for colonization of the lower respiratory tract (specifically the trachea) and that it allows Bordetella to suppress the inflammatory response of its hosts. FHA is also one of the prototypical members of the Two Partner Secretion (TPS) pathway family. Our previous studies showed that the topology of FHA on the bacterial surface was the opposite of what had been assumed and led to the development of a new model for TPS. Our studies also demonstrated the importance of studying secretion and function simultaneously as results from secretion experiments revealed insight into function and vice versa. We propose experiments to determine how FHA modulates inflammation in the respiratory tract, to identify host cell receptors for FHA, and to identify specific regions and amino acids within FHA that are important for receptor binding. In addition to revealing mechanisms of FHA function, our results may identify novel pathways by which inflammation is controlled in general. We will also determine how the C-terminus of the FHA precursor, FhaB, controls maturation and release of FHA from the bacterial surface. Our results will provide insight into the TPS mechanism, and may set a new paradigm for how proteins are folded on cell surfaces. PUBLIC HEALTH RELEVANCE: Pertussis (also known as whooping cough) remains a public health problem and cases are on the rise in developed countries due, apparently, to waning immunity in adolescents and adults who were vaccinated, rather than infected, as children. We will conduct experiments to determine how one of the proteins included in the acellular pertussis vaccine, Filamentous Hemagglutinin (FHA), functions during infection to influence the inflammatory response. We will also investigate the complex mechanism by which the FHA protein is exported to the bacterial cell surface. Understanding FHA secretion and function is critical for the development of more efficacious pertussis vaccines.

描述（由申请人提供）：百日咳（也称为百日咳）仍然是一个全球健康问题，估计每年有4500万例病例和300,00例死亡，主要发生在儿童中。尽管疫苗覆盖范围很高，但自1990年代以来，几个发达国家的发病率一直在增加，这显然是由于青少年和年轻人的免疫力减弱，而他们的疫苗接种而不是被感染的儿童，尤其是那些接种了艾滋病疫苗的人。了解疫苗成分在发病机理和免疫力中的作用对于改善疫苗的发展至关重要。百日咳的致病药物是百日咳Bordetella和Bordetella parapertussishu。这些严格的人类特异性病原体与Bordetella支气管炎极为密切相关，Bordetella tronchiseptica具有广泛的宿主范围，其中几乎包括所有哺乳动物。我们一直在采用一种比较方法，包括所有这三个Bordetella uspecies，用于研究毒力基因调节的作用以及特定的毒力因子在发病机理中的作用。使用支气管杆菌链球菌使我们能够在天然细菌宿主相互作用的背景下研究实验室中的呼吸道感染，以及使用嵌合支支气管杆菌和B. b. bittussis菌株的使用，表达异源性毒力因子的菌株使我们能够证明几种毒力因素，包括丝状性血素蛋白（fha）（FHA），是可互动的。 FHA是一种大型表面相关和分泌的蛋白质，也是百日咳疫苗的主要成分之一。我们已经表明，下呼吸道定植（特别是气管）需要FHA，并且它允许Bordetella抑制其宿主的炎症反应。 FHA也是两个合作伙伴分泌（TPS）途径家族的原型成员之一。我们先前的研究表明，FHA在细菌表面上的拓扑与假设的相反，并导致了TPS的新模型的发展。我们的研究还证明了同时研究分泌和功能的重要性，因为分泌实验的结果揭示了对功能的见解，反之亦然。我们提出了实验，以确定FHA如何调节呼吸道中的炎症，鉴定FHA的宿主细胞受体，并鉴定FHA内的特定区域和氨基酸对受体结合很重要。除了揭示FHA功能的机制外，我们的结果还可以确定一般控制炎症的新途径。我们还将确定FHA前体的C末端如何控制FHA从细菌表面的成熟和释放。我们的结果将提供对TPS机制的洞察力，并可能为蛋白质在细胞表面上折叠的方式设定新的范式。公共卫生的相关性：百日咳（也称为百日咳）仍然是一个公共卫生问题，而且由于显然是由于儿童而不是被疫苗而不是感染的儿童疫苗接种而不是感染的成年人的免疫力，因此发达国家的病例正在增加。我们将进行实验，以确定一种蛋白质在感染过程中的蛋白质中如何包括在感染过程中的丝状疫苗，丝状血凝素（FHA），以影响炎症反应。我们还将研究将FHA蛋白导出到细菌细胞表面的复杂机制。了解FHA的分泌和功能对于开发更有效的百日咳疫苗至关重要。