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

基本信息

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
项目类别：
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

项目摘要

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：修订幽门螺杆菌主要在感染了携带细胞毒素相关基因致病岛 (cagPAI) 的菌株的个体中引起临床疾病。 cagPAI 编码 IV 型分泌系统 (T4SS)，该系统是将 CagA 癌蛋白注射到上皮细胞并进行诱导所需的。促炎细胞因子白细胞介素 8 (IL-8) 是幽门螺杆菌 T4SS 的重要组成部分，具有不寻常的序列。我们已经在小鼠和非人类灵长类动物模型中证明，CagY 中免疫驱动的宿主选择足以预测框内插入或删除。导致幽门螺杆菌 T4SS 功能的获得或丧失我们发现 CagY 的功能是作为一种分子变阻器，改变 T4SS 的功能并“调节”宿主炎症反应。我们提出了三个具体目标来检验这一假设，在目标 1 中，我们将确定 CagY 重组改变表达变异 CagY 蛋白的同基因菌株的功能或非功能的机制。功能性 T4SS 将用于确定 CagY 结合 β1 整合素并通过 β1 整合素发出信号的能力，表征细菌膜中 CagY 的拓扑结构，检查 CagY 与其他重要 PAI 之间的相互作用蛋白质，并确定 DNA 重复是否对 T4SS 功能至关重要。在目标 2 中，我们将使用敲除和转基因小鼠模型来表征宿主免疫在幽门螺杆菌 T4SS 中 CagY 介导的功能调节中的作用。目标 3 是使用高度相关的恒河猴模型和来自慢性感染患者的菌株更好地了解 CagY 和 T4SS 功能的生理作用，完成这些实验将表征细菌的新策略。分泌系统改变宿主免疫反应，并确定 T4SS 和宿主免疫交叉的机制。这些实验也将增强我们对 PAI 与感染临床结果之间关系的理解，并导致对两者之间关系的更广泛理解。慢性感染和炎症。