Neutrophil Plasticity and H. pylori Pathogenesis

中性粒细胞可塑性和幽门螺杆菌发病机制

基本信息

批准号：
9109153
负责人：
Lee-Ann H Allen
金额：
$ 17.47万
依托单位：
UNIVERSITY OF IOWA
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-01-11 至 2020-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9109153
关键词：
Accounting Activities of Daily Living Address Antibiotic Resistance Apoptosis Bacteria Biochemical Biopsy Specimen Carcinogens Cell Death Cells Cessation of life Chronic Coculture Techniques Collection Complex Confocal Microscopy Cytoplasmic Granules DNA Data Development Disease Electron Microscopy Enzymes Epithelium Evaluation Gastric mucosa Gastritis Gene Expression Goals Growth Health Helicobacter Infections Helicobacter pylori Hour Human Immune response Infection Inflammatory Response Inhibition of Apoptosis Knowledge Link Locales Longevity Malignant neoplasm of lung Methods Microfluidic Microchips Modeling Molecular Mucous body substance NADPH Oxidase Pathogenesis Pathway interactions Patients Peptic Ulcer Phagosomes Phenotype Process Production Proteins Reactive Oxygen Species Resolution Role Staging Stomach T-Lymphocyte Testing Therapeutic Time Tissues Treatment Efficacy Vaccines Variant Virulence Virulence Factors arginase base cytokine extracellular high throughput analysis in vivo killings malignant stomach neoplasm mutant neutrophil novel novel therapeutics pathogen prevent roscovitine trafficking transcriptome sequencing

项目摘要

DESCRIPTION (provided by applicant): Helicobacter pylori is a bacterial pathogen that infects the gastric mucosa of 50% of humans worldwide and elicits gastritis that can progress to peptic ulcers or gastric cancer, which accounts for more than 650,000 deaths each year. No vaccine is available to prevent or treat H. pylori infection, and antibiotic resistance is an ever-increasing problem that undermines treatment efficacy. A distinguishing feature of H. pylori infection is the chronic, polymorphonuclear leukocyte (PMN, neutrophil)-dominant inflammatory response. Patient biopsy samples demonstrate that PMNs reach the mucus layer over the gastric epithelium and engulf large numbers of bacteria in this locale. However, H. pylori is not killed and NADPH oxidase-derived reactive oxygen species (ROS) released into the extracellular milieu damage host tissue. Despite the central role of neutrophils in H. pylori pathogenesis, our understanding of bacteria-PMN interactions is rudimentary. Thus, we undertook this study to address critical knowledge gaps regarding the phenotype and fate of infected PMNs and their bacterial cargo. To this end, we created a collection of isogenic bacterial mutants that lack major virulence factors alone or in combination, and also exploited recent discoveries that have revolutionized our understanding of the role of neutrophils in the immune response, as indicated by their immunomodulatory capacity and ability to undergo subtype differentiation in vivo. Our central hypothesis is that H. pylori exploits PMN phenotypic plasticity as part of its virulence strategy. Consistent with this, we present extensive, convincing preliminary data to suggest that H. pylori-neutrophil interactions are significantly more complex than previously appreciated, and which define three distinct stages of infection. During early infection H. pylori evades killing by manipulation of phagosome maturation and granule targeting. This is followed a few hours later by induction of PMN subtype differentiation. In parallel, PMN apoptosis is significantly impaired, and cell lifespan is prolonged. After about 3 days infected PMNs succumb, not by delayed apoptosis, but rather by an atypical mechanism of death that supports robust extracellular H. pylori growth upon and around dying PMN carcasses. To test this infection model we will in three specific aims analyze bacterial trafficking and degranulation, define changes in PMN phenotype and functional capacity, elucidate the effects of H. pylori on PMN lifespan and mechanism of cell death, and begin to determine the roles of major bacterial virulence factors in these aspects of disease. Methods utilized will include but are not limited to super-resolution confocal microscopy, electron microscopy, RNA-Seq, and high-throughput analysis of cytokine production using Fluidigm microfluidic chips. Finally, we will also determine if clinically approve PMN apoptosis-inducing agents can accelerate PMN death or undermine Hp survival as a first step toward evaluation of their therapeutic potential.

描述（由申请人提供）：幽门螺杆菌是一种细菌病原体，可感染全世界 50% 的人的胃粘膜，引发胃炎，并可进展为消化性溃疡或胃癌，每年导致超过 650,000 人死亡。可用于预防或治疗幽门螺杆菌感染，而抗生素耐药性是一个日益严重的问题，削弱了治疗效果。幽门螺杆菌感染是一种以多形核白细胞（PMN，中性粒细胞）为主的慢性炎症反应。患者活检样本表明，PMN 到达胃上皮上的粘液层并吞噬该部位的大量细菌。尽管嗜中性粒细胞在嗜中性粒细胞中发挥着核心作用，但它们并未被杀死，并且 NADPH 氧化酶衍生的活性氧 (ROS) 释放到细胞外环境中会损害宿主组织。由于幽门螺杆菌的发病机制，我们对细菌与中性粒细胞相互作用的了解还很初级，因此，我们进行这项研究是为了解决有关受感染中性粒细胞及其细菌的表型和命运的关键知识差距。缺少专业单独或组合毒力因子，并且还利用了最近的发现，这些发现彻底改变了我们对中性粒细胞在免疫反应中的作用的理解，正如它们的免疫调节能力和在体内进行亚型分化的能力所表明的那样，我们的中心假设是幽门螺杆菌。利用 PMN 表型可塑性作为其毒力策略的一部分，与此一致，我们提供了广泛的初步数据表明幽门螺杆菌 - 中性粒细胞相互作用比以前更加复杂。赞赏，并定义了感染早期的三个不同阶段，幽门螺杆菌通过逃避杀灭。几个小时后，PMN 亚型分化被诱导，并且细胞寿命在大约 3 天后死亡，而不是延迟凋亡。而是通过支持细胞外幽门螺杆菌在垂死的 PMN 尸体上和周围强劲生长的非典型死亡机制来测试这种感染模型，我们将在三个特定目标中分析细菌运输和脱颗粒，定义中性粒细胞表型和功能能力的变化，阐明幽门螺杆菌对中性粒细胞寿命和细胞死亡机制的影响，并开始确定主要细菌毒力因子在疾病这些方面的作用，所用方法包括但不限于。最后，我们还将确定是否获得临床批准。 PMN 凋亡诱导剂可以加速 PMN 死亡或破坏 Hp 存活，这是评估其治疗潜力的第一步。