Identifying host genetic determinants of Coxiella burnetii pathogenesis

鉴定伯氏柯克斯体发病机制的宿主遗传决定因素

• 批准号: 9387775
• 负责人: Alan Gabriel Goodman
• 金额: $ 22.95万
• 依托单位: WASHINGTON STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-15 至 2019-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9387775
• 关键词: Acute; Acute Disease; Address; Adult; Affect; Animal Model; Animals; Arthropods; Bacteria; Biological Models; Categories; Cells; Centers for Disease Control and Prevention (U.S.); Chronic; Complex; Coxiella; Coxiella burnetii; Data; Development; Disease; Disease Progression; Drosophila genus; Drosophila melanogaster; Endocarditis; Evaluation; Exhibits; Female; Gene Expression; Genes; Genetic; Genetic Determinism; Genetic Polymorphism; Genetic Screening; Genome; Genotype; Goals; Health; Hemocytes; Homologous Gene; Human; Immune; Immune response; Immune system; Immunocompetent; Inbreeding; Individual; Infection; Influenza; Innate Immune Response; Insecta; Integration Host Factors; Intercistronic Region; Kinetics; Knowledge; Larva; Libraries; Lipopolysaccharides; Mammalian Cell; Methods; Modeling; Monitor; Moths; Mus; National Institute of Allergy and Infectious Disease; Outcome; Pathogenesis; Pathogenicity; Pathway interactions; Phase; Play; Population; Predisposition; Q Fever; Recombinants; Research; Risk Factors; Role; Ruminants; Selection for Treatments; Signal Pathway; Symptoms; System; Testing; Text; Therapeutic Intervention; Ubiquitin-Conjugating Enzymes; Validation; Variant; Virulence Factors; Waxes; Work; Zoonoses; base; biodefense; clinical application; combat; fly; gene discovery; gene function; gene synthesis; genetic variant; genome wide association study; human disease; improved; in vitro Assay; innovation; knock-down; macrophage; mortality; mouse model; novel; novel strategies; outcome forecast; overexpression; pathogen; screening; targeted treatment; tool

Project Summary/Abstract: Coxiella burnetii is a Gram-negative, obligate intracellular, macrophage-tropic bacterium and the causative agent of the zoonotic disease Q fever. Acute phase of the disease in humans is characterized primarily by influenza-like symptoms, and approximately 3-5% of the infected individuals develop chronic infection, which is characterized by endocarditis. Association between host genetic background and the development of Coxiella infection has been demonstrated both in humans and animals; however, specific genes associated with susceptibility to infection remain largely unknown. A powerful tool to study the impact of host genetics on pathogenic infection is the model organism Drosophila melanogaster. The Drosophila Genetics Reference Panel (DGRP) is a fully sequenced panel of fly lines derived from a natural population that is used to as a living library to test how polymorphisms affect complex host responses. Thus, to address the knowledge gap regarding how host genetics affects Coxiella pathogenesis, we propose to identify host genetic variants implicated in susceptibility to Coxiella infection using Drosophila melanogaster. Our preliminary data demonstrate that Drosophila exhibit mortality and host immune responses following infection with the BSL2 phase II clone 4 strain of C. burnetii that has a deletion in lipopolysaccharide synthesis genes but retains other virulence factors. The phase II strain has similar intra-macrophage replication kinetics as BSL3 phase I C. burnetii and causes lethality in wax moth larvae. Similarly, Drosophila succumb to Coxiella phase II clone 4 and thus can be used as a novel host model for Coxiella infection. Moreover, our pathway-unbiased screening approach will significantly improve upon ongoing studies of Coxiella in mammalian systems. We hypothesize that the DGRP lines will reveal genetic variants in immune response- related genes associated with susceptibility to Coxiella infection. In Specific Aim 1 we will use DGRP lines to perform a genome-wide association study (GWAS) and screen for genetic variants associated with susceptibility to Coxiella infection. In Specific Aim 2 we will use genetically recombinant fly lines and in vitro assays to knockdown or over-express genes with identified variants for validation and further functional evaluation of the gene's impact on Coxiella pathogenesis. Additionally, since a majority of known human disease genes have recognizable homologues in Drosophila, we will take advantage of these genetic similarities to ask how homologous genes identified in our screen function during Coxiella infection in human cells. Through the proposed work we will identify host genetic determinants of susceptibility to Coxiella infection in Drosophila and mammalian hosts. Our findings will have broad-ranging impacts by identifying host factors that when dysfunctional confer susceptibility to Coxiella infection. These results will be important for better prediction of pathogen spread in domestic ruminant reservoirs and disease progression in humans.

项目摘要/摘要： Coxiella burnetii是一种革兰氏阴性，强制性细胞内，巨噬细胞 - 循环细菌， 人畜共患病的病因Q热。特征是人类疾病的急性阶段 主要由类似流感的症状出现，大约3-5％的感染者发展出慢性 感染，其特征是心内膜炎。宿主遗传背景与 在人类和动物中都已经证明了考克斯菌感染的发展。但是，具体 与感染易感性相关的基因在很大程度上尚不清楚。研究的强大工具来研究 致病感染的宿主遗传学是模型生物果蝇。果蝇 遗传学参考面板（DGRP）是一个完全测序的飞行线，该面板源自自然人群， 被用作活库来测试多态性如何影响复杂的宿主反应。因此，解决 关于宿主遗传学如何影响柯西埃拉发病机理的知识差距，我们建议识别宿主 遗传变异涉及使用果蝇的易感性感染的易感性。 我们的初步数据表明果蝇表现出死亡率和宿主免疫反应 在用BSL2 II期克隆4菌株感染后，在脂多糖中缺失了 合成基因但保留其他毒力因子。 II期应变具有相似的巨噬细胞内复制 动力学作为BSL3 I期C. burnetii，并在蜡虫幼虫中引起致死性。同样，果蝇屈服于 Coxiella II期克隆4，因此可以用作Coxiella感染的新型宿主模型。而且，我们的 在对Coxiella的持续研究中，途径不稳定的筛选方法将显着改善 哺乳动物系统。我们假设DGRP线将揭示免疫反应中的遗传变异 与Coxiella感染的易感性相关的相关基因。在特定目标1中，我们将使用DGRP线 进行全基因组关联研究（GWAS）和筛选与相关的遗传变异 对考克斯菌感染的敏感性。在特定目标2中，我们将使用遗传重组蝇线和体外 具有确定验证和进一步功能的变体的敲低或过表达基因的测定 评估基因对考克斯菌发病机理的影响。此外，由于大多数已知人类 疾病基因在果蝇中具有可识别的同源物，我们将利用这些遗传 相似性，询问在人类感染期间我们的筛选功能中鉴定出同源基因的相似之处 细胞。 通过拟议的工作，我们将确定对Coxiella易感性的宿主遗传决定因素 果蝇和哺乳动物宿主的感染。我们的发现将通过识别主机产生广泛的影响 当功能失调的会议易感性对考克斯菌感染的敏感性时。这些结果对 在家庭反刍动物储层中更好地预测病原体的传播和人类疾病的进展。