Colonization and Pathogenicity Determinants of C. jejuni

空肠弯曲菌的定植和致病性决定因素

• 批准号: 7665440
• 负责人: Victor J. DiRita
• 金额: $ 37.42万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-01 至 2012-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7665440
• 关键词: Animal Model; Bacteria; Bacterial Gastroenteritis; Basic Science; Behavior; Biological Assay; Biology; Campylobacter; Campylobacter infection; Campylobacter jejuni; Categories; Cells; Centers for Disease Control and Prevention (U.S.); Chickens; Classification; Colon; Controlled Study; Development; Eating; Escherichia coli; Gastrointestinal tract structure; Genes; Human; Immune response; Infection; Inflammation; Intestines; Knowledge; Link; Modeling; Mutagenesis; National Institute of Allergy and Infectious Disease; Organism; Pathogenicity; Phenotype; Protein Glycosylation; Proteins; Reagent; Rectum; Relative (related person); Reporting; Research; Role; Salmonella; Screening procedure; Shigella; Source; Stomach; System; Testing; Translating; United States; Virulence; Work; biodefense; design; foodborne; genetic analysis; in vitro Model; in vivo; link protein; mutant; pathogen; research study; small molecule libraries; trait; waterborne

DESCRIPTION (provided by applicant): Campylobacter jejuni is the most prevalent cause of bacterial gastroenteritis in the United States, and is also designated a Category B food-and waterborne pathogen under the NIAID Biodefense Research Agenda. Case numbers for C. jejuni annually surpass those of Escherichia coli, Shigella and, in some years, even Salmonella species. The Centers for Disease Control have estimated that there are up to 2 million illnesses from campylobacteriosis each year, considering reported and unreported cases. A large number of human cases are acquired by eating contaminated and poorly prepared chicken. Infection of humans results in inflammation of the lower intestinal tract that ultimately involves the colon and rectum. Despite the importance of the organism as a human pathogen, its mechanisms of virulence are poorly understood relative to those of other pathogens. Campylobacter colonization determinants were identified in a signature-tagged mutagenesis screen using a chick infection model. Among the genes identified in this screen were those required for N-linked protein glycosylation system, called pgl genes. The role of protein glycosylation in the biology and pathogenicity-related behavior of C. jejuni is not defined, but systematic genetic analysis of the N-linked glycome of C. jejuni has revealed a subset of these genes that are required for colonization in a chick model. Aim 1 will investigate three of these proteins and determine their roles in both in vivo and in vitro models of C. jejuni pathogenicity as well as the specific effect of protein glycosylation on them. Aim 2 will investigate the chick model further with two specific sub-aims: the first is to analyze the fate of mutant, poorly colonizing bacteria after oro-gastric inoculation and throughout the gastrointestinal tract and the second is to test the hypothesis that mutant bacteria that do not colonize the chicken with wild type efficacy induce a unique innate immune response that contributes to their poor colonization phenotype. Aim 3 will develop and apply assays for screening a library of small molecules for those that inhibit key traits of C. jejuni pathogenicity including protein glycosylation and flagellar assembly. This project will uncover new knowledge about an important human pathogen, Campylobacter jejuni. Experiments are designed to define the role of glycosylated proteins in host-cell association and in two animal models of colonization, including chickens, a natural reservoir of C. jejuni and major source of human infection. The work includes a component that will translate the knowledge from the basic science in this application to development of new reagents for studying and controlling C. jejuni infections.

描述（由申请人提供）：空肠弯曲菌是美国细菌性胃肠炎最常见的原因，并且根据 NIAID 生物防御研究议程也被指定为 B 类食品和水源性病原体。空肠弯曲菌每年的病例数超过了大肠杆菌、志贺氏菌，在某些年份甚至超过了沙门氏菌。美国疾病控制中心估计，考虑到已报告和未报告的病例，每年有多达 200 万例弯曲菌病导致疾病。大量人类病例是通过食用受污染和处理不当的鸡肉而感染的。人类感染会导致下肠道炎症，最终累及结肠和直肠。尽管该生物体作为人类病原体很重要，但相对于其他病原体，其毒力机制却知之甚少。使用小鸡感染模型在标记诱变筛选中鉴定了弯曲杆菌定植决定因素。本次筛选中鉴定出的基因包括 N 连接蛋白糖基化系统所需的基因，称为 pgl 基因。蛋白质糖基化在空肠弯曲菌的生物学和致病性相关行为中的作用尚未确定，但对空肠弯曲菌 N 联糖组的系统遗传分析揭示了这些基因的一个子集，这些基因是在雏鸡中定植所需的模型。目标 1 将研究其中三种蛋白质，并确定它们在空肠弯曲菌致病性体内和体外模型中的作用以及蛋白质糖基化对它们的具体影响。目标 2 将进一步研究小鸡模型，有两个具体的子目标：第一个是分析口胃接种后和整个胃肠道中定殖不良的突变细菌的命运，第二个是检验突变细菌的假设不具有野生型功效的定植鸡会诱导独特的先天免疫反应，从而导致其较差的定植表型。目标 3 将开发并应用检测方法来筛选小分子文库，寻找抑制空肠弯曲菌致病性关键特征（包括蛋白质糖基化和鞭毛组装）的小分子。 该项目将揭示有关重要人类病原体空肠弯曲菌的新知识。实验旨在确定糖基化蛋白在宿主细胞关联和两种定植动物模型中的作用，其中包括鸡，空肠弯曲菌的天然储存库和人类感染的主要来源。这项工作包括将本应用中的基础科学知识转化为开发用于研究和控制空肠弯曲菌感染的新试剂的部分。