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

• 批准号: 8099583
• 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
• 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/8099583
• 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

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）是由百日咳博德泰拉引起的疾病所必需的，在过去的二十年里，百日咳在美国重新出现。8种博德特拉菌中有7种表达AC毒素，它们会导致人类和一系列动物的呼吸系统疾病。该毒素分子是腺苷酸环化酶和一个与毒素重复序列（RTX）家族同源的结合域的独特杂交产物。AC毒素通过与细胞膜结合并将其催化结构域跨脂质双分子层易位而使宿主细胞中毒，导致细胞内cAMP的不调节生成。通过对催化结构域的抗体或某些突变的预防易位将增强毒素的其他主要功能，形成寡聚孔，导致红细胞溶解，并有助于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，CD11b/CD18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毒素与CD11b/CD18之间的关系尚不明确。我们的初步数据表明，CD11b/CD18不仅增加了细胞对中毒的敏感性，而且当高浓度的毒素应用于细胞时，实际上限制了中毒，同时可能促进低聚物的形成。我们将研究AC毒素与cd11b /CD18相互作用的基本机制。毒素结合和功能的决定因素可以解释一个新的发现：上皮单层细胞对施加于顶端表面的AC毒素中毒不敏感，这令人惊讶，因为毒素可以中毒迄今为止测试的所有细胞类型，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隙的机制，以及所有博德氏菌引起的疾病的发病机制。这个项目将继续我从19岁开始对基础科学的兴趣。我的导师埃里克·休利特博士拥有超过25年研究百日咳博德泰拉的经验，是细菌毒素领域的杰出科学家。他强调通过科学合作来学习，这将补充我的结构化课程计划。K08奖，结合我的导师和弗吉尼亚大学的资源，将为我作为一名临床科学家的全面发展提供必要的支持。