Bordetella adenylate cyclase toxin: the role of cell interaction in toxin functio

博德特氏菌腺苷酸环化酶毒素：细胞相互作用在毒素功能中的作用

基本信息

批准号：
8289635
负责人：
Joshua Clark Eby
金额：
$ 12.98万
依托单位：
UNIVERSITY OF VIRGINIA
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-07-01 至 2014-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8289635
关键词：
Accounting Adenylate Cyclase Adenylate Cyclase Toxin Affect Age Animals Antibodies Apical Award Bacteria Bacterial Proteins Bacterial Toxins Basic Science Binding Biological Assay Bordetella Bordetella pertussis CD11 Antigens Calmodulin Catalytic Domain Cell Communication Cell Death Cell membrane Cells Chemicals Chinese Hamster Ovary Cell Collaborations Complement Cyclic AMP Cytolysis Data Development Disease Energy Transfer Enzymes Epithelial Epithelial Cells Epithelium Erythrocytes Family Generations Hemolysis Human Hybrids ITGAM gene ITGB2 gene In Vitro Infection Inflammatory Integrins Intoxication Investigation Knowledge Learning Light Lipid Bilayers Lipids Lung diseases Measurement Measures Membrane Mentors Methods Mutation Oligosaccharides Pathogenesis Pertussis Prevention Relative (related person)Research Personnel Resources Respiratory Tract Infections Role Scientist Sheep Small Interfering RNA Structure Structure of respiratory epithelium Surface Techniques Testing Toxin United States Universities Uropathogenic E. coli Virginia Virulence Factors apical membrane basolateral membrane cell type crosslink cytokine experience in vivo interest macrophage member monolayer mutant neutrophil novel pathogenic bacteria polypeptide prevent receptor respiratory scorpion toxin I&apos &apos

项目摘要

DESCRIPTION (provided by applicant): The adenylate cyclase toxin (AC toxin) is necessary for disease caused by Bordetella pertussis, which has reemerged in the United States over the last two decades. AC toxin is expressed by seven of eight species of Bordetella which cause respiratory disease in humans and a range of animals. The toxin molecule is a unique hybrid of an adenylate cyclase enzyme and a binding domain homologous to the repeats-in-toxin (RTX) family of pore-forming bacterial protein toxins. AC toxin intoxicates host cells by binding to the cell membrane and translocating its catalytic domain across the lipid-bilayer, resulting in unregulated generation of intracellular cAMP. Prevention of translocation by an antibody to the catalytic domain or by certain mutations will enhance the other major function of the toxin, formation of oligomeric pores which cause lysis of erythrocytes and contribute to non-apoptotic cell death of macrophages. The magnitude of intoxication correlates with the relative surface expression of the (32 integrin, CD11b/CD18, a receptor expressed most abundantly on neutrophils and macrophages; however, the relationship between AC toxin and CD11b/CD18 is not well defined. Our preliminary data show that CD11b/CD18 does not simply increase sensitivity of cells to intoxication, but, when high concentrations of toxin are applied to cells, actually limits intoxication while possibly enhancing oligomer formation. We will investigate the basic mechanisms of the interaction between AC toxin and CD11 b/CD18. The determinants of toxin binding and function may explain a novel finding: cells of an epithelial monolayer are insensitive to intoxication by AC toxin applied to the apical surface, surprising because the toxin can intoxicate all cell types so far tested, and important because the bacterium first encounters these cells upon infection. These studies will shed light upon the mechanism of pore formation by bacterial toxins, and the pathogenesis of disease caused by all Bordetellae. The proposed project will continue my interest in basic science that began at the age of 19. My mentor, Dr. Erik Hewlett, with over 25 years of experience" studying Bordetella pertussis, is a preeminent scientist in the field of bacterial toxins. His emphasis on learning through scientific collaboration will complement my plan for structured coursework. The K08 award, in combination with the resources of my mentor and the University of Virginia, will provide me with the support necessary for my full development as a clinician scientist. RELEVANCE: AC toxin is expressed by seven of the eight species of Bordetella and is also a member of the RTX family of pore-forming bacterial protein toxins that are produced by other pathogenic bacteria such as uropathogenic Escherichia coli. Here, we will characterize the basic mechanisms of cell binding by AC toxin and show that these mechanisms affect the function of the toxin and determine its role as a virulence factor.

描述（由申请人提供）：腺苷酸环化酶毒素（AC 毒素）是百日咳博德特氏菌引起的疾病所必需的，百日咳博德特氏菌在过去二十年中在美国重新出现。 AC 毒素由八种博德特氏菌中的七种表达，可引起人类和一系列动物的呼吸道疾病。该毒素分子是腺苷酸环化酶和与成孔细菌蛋白毒素的毒素重复序列 (RTX) 家族同源的结合域的独特杂合体。 AC 毒素通过与细胞膜结合并将其催化结构域跨脂质双层移位而使宿主细胞中毒，导致细胞内 cAMP 的生成不受调节。通过抗体或某些突变来防止易位将增强毒素的其他主要功能，即寡聚孔的形成，其导致红细胞裂解并导致巨噬细胞的非凋亡细胞死亡。中毒程度与 (32 整合素、CD11b/CD18) 的相对表面表达相关，这是一种在中性粒细胞和巨噬细胞上表达最丰富的受体；然而，AC 毒素和 CD11b/CD18 之间的关系尚未明确。我们的初步数据显示CD11b/CD18 不仅仅增加细胞对中毒的敏感性，而且当高浓度的毒素作用于细胞时，实际上限制了中毒，同时可能增强我们将研究 AC 毒素和 CD11 b/CD18 之间相互作用的基本机制。毒素结合和功能的决定因素可能解释一个新的发现：上皮单层细胞对施加到顶端的 AC 毒素不敏感。令人惊讶的是，迄今为止所测试的毒素可以使所有细胞类型中毒，而且重要的是，细菌在感染时首先遇到这些细胞。这些研究将揭示细菌毒素形成孔的机制，以及细菌毒素形成孔的机制。发病机制所有博德氏菌引起的疾病。拟议的项目将延续我从 19 岁时开始对基础科学的兴趣。我的导师 Erik Hewlett 博士拥有超过 25 年研究百日咳博德特氏菌的经验，是细菌毒素领域的杰出科学家。他的重点通过科学合作学习将补充我的结构化课程计划，结合我的导师和弗吉尼亚大学的资源，将为我作为临床科学家的全面发展提供必要的支持。相关性：AC 毒素由八种博德特氏菌中的七种表达，也是成孔细菌蛋白毒素 RTX 家族的成员，该家族由其他病原菌（如尿路致病性大肠杆菌）产生。在这里，我们将描述 AC 毒素与细胞结合的基本机制，并表明这些机制影响毒素的功能并决定其作为毒力因子的作用。