Functional Plasticity in the Helicobacter pylori Type IV Secretion System

幽门螺杆菌 IV 型分泌系统的功能可塑性

• 批准号: 8889192
• 负责人: JAY V. SOLNICK
• 金额: $ 55.82万
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-07-07 至 2019-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8889192
• 关键词: Antigens; B-Lymphocytes; Bacteria; Binding; Cell Culture Techniques; Cell Lineage; Cells; Chronic; Clinical; Cytotoxin; DNA; Disease; Epithelial Cells; Genes; Genetic Recombination; Goals; Gram-Negative Bacteria; Health; Helicobacter pylori; Human; Immune; Immune response; Immunity; In Vitro; Individual; Infection; Inflammation; Inflammatory; Inflammatory Response; Injection of therapeutic agent; Integration Host Factors; Integrin Binding; Integrins; Interleukin-8; Knockout Mice; Lead; Link; Macaca mulatta; Mediating; Membrane; Modeling; Molecular; Monkeys; Morphologic artifacts; Mus; Nitrogen; Oncogene Proteins; Outcome; Oxygen; Pathogenicity Island; Patients; Peptic Ulcer; Physiological; Pilum; Protein Region; Proteins; Publishing; Role; Signal Transduction; Sorting - Cell Movement; Stomach; Structure; Surface; System; T-Lymphocyte; TLR5 gene; Testing; Transgenic Mice; Type IV Secretion System Pathway; Variant; Virulence Factors; adaptive immunity; arm; base; chemokine; cohort; cytokine; fitness; functional plasticity; gain of function; in vivo; loss of function; malignant stomach neoplasm; mouse model; nonhuman primate; novel; novel strategies; pathogen; research study; tool; transmission process

PROJECT SUMMARY/ABSTRACT: revised Helicobacter pylori causes clinical disease primarily in those individuals infected with a strain that carries the cytotoxin associated gene pathogenicity island (cagPAI). The cagPAI encodes a type IV secretion system (T4SS) that is required for injection of the CagA oncoprotein into epithelial cells and induction of the proinflammatory cytokine, interleukin-8 (IL-8). CagY is an essential component of the H. pylori T4SS that has an unusual sequence structure, in which an extraordinary number of direct DNA repeats is predicted to cause rearrangements that invariably predict in-frame insertions or deletions. We have demonstrated in murine and non-human primate models that immune-driven host selection of rearrangements in CagY is sufficient to cause gain or loss of function in the H. pylori T4SS. We hypothesize that CagY functions as a sort of molecular rheostat that alters the function of the T4SS and “tunes” the host inflammatory response so as to maximize persistent infection. We propose three specific aims to test this hypothesis. In Aim 1 we will determine the mechanism by which recombination in CagY alters the function of the H. pylori T4SS. Isogenic strains expressing variant CagY proteins that confer a functional or non-functional T4SS will be used to determine the capacity of CagY to bind and signal through β1 integrins, characterize the topology of CagY in the bacterial membrane, examine the interaction between CagY and other essential PAI proteins, and determine if the DNA repeats are essential for T4SS function. In Aim 2 we will characterize the role of host immunity in selection for CagY-mediated modulation of function in the H. pylori T4SS using knockout and transgenic mouse models. The goal of Aim 3 is to better understand the physiological role of CagY and T4SS function using the highly relevant rhesus macaque model and strains from chronically infected patients. Completion of these experiments will characterize a novel strategy by which a bacterial secretion system alters the host immune response, and identify the mechanisms where the T4SS and host immunity intersect. These experiments will also enhance our understanding of the relationship between the PAI and the clinical outcome of infection, and lead to a broader understanding of the relationship between chronic infection and inflammation.

项目摘要/摘要：修订 幽门螺杆菌幽门螺杆菌在感染菌株的人中导致临床疾病主要，该菌株带有细胞毒素相关的基因致病岛（CAGPAI）。 CAGPAI编码将CAGA癌蛋白注射到上皮细胞中所必需的IV型分泌系统（T4SS）以及促炎细胞因子Interleukin-8（IL-8）的诱导。 CAGY是幽门螺杆菌T4SS的重要组成部分，其具有不寻常的序列结构，其中预计有很多直接DNA重复序列会导致重排，从而总是预测框内插入或删除。我们已经在鼠和非人类私有模型中证明了免疫驱动的CAGY重排的宿主选择足以在幽门螺杆菌T4SS中引起功能的增益或丧失。我们假设CAGY充当一种分子变势，它改变了T4SS的功能并“调音”宿主炎症反应，从而最大程度地持续感染。我们提出了三个特定的目的来检验这一假设。在AIM 1中，我们将确定CAGY中重组改变幽门螺杆菌T4SS的功能的机制。表达变异CAGY蛋白的等源性菌株将使用功能性或非功能性T4SS来确定CAGY通过β1整合蛋白结合和信号的能力，表征细菌膜中CAGY的拓扑，检查CAGY和其他必要的PAI蛋白之间的相互作用，并确定DNA是否具有DNA的相互作用，并确定DNA是否具有t4ss的功能。在AIM 2中，我们将使用基因敲除和转基因小鼠模型来表征宿主免疫在选择CAGY介导的功能调制的作用中的作用。 AIM 3的目标是更好地了解CAGY和T4SS功能的物理作用，并使用高度相关的猕猴模型和慢性感染患者的菌株。这些实验的完成将表征一种新型策略，通过该策略，细菌分泌系统会改变宿主免疫响应，并确定T4SS和宿主免疫学相交的机制。这些实验还将增强我们对PAI与感染临床结果之间关系的理解，并使人们对慢性感染与感染之间的关系有更广泛的了解。