Type IV Protein Secretion in Helicobacter pylori

幽门螺杆菌中 IV 型蛋白的分泌

• 批准号: 10595676
• 负责人: TIMOTHY L COVER
• 金额: $ 71.49万
• 依托单位: VANDERBILT UNIVERSITY MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-02-18 至 2026-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10595676
• 关键词: Address; Animal Model; Antibiotic Resistance; Antibiotics; Architecture; Bacteria; Biological Assay; Cancer Etiology; Carcinogens; Cell Culture Techniques; Cells; Cessation of life; Chromosome Mapping; Chronic; Clarithromycin; Classification; Clinical; Complex; Cryoelectron Microscopy; DNA; Disease; Duodenal Ulcer; Elements; Event; Exhibits; Funding; Gastric Adenocarcinoma; Gastric lymphoma; Gastric mucosa; Gastric ulcer; Gene Expression; Genes; Genetic Techniques; Goals; Gram-Negative Bacteria; Helicobacter Infections; Helicobacter pylori; Helicobacter pylori induced gastric cancer; Homologous Gene; Human; Incidence; Individual; Infection; Knowledge; Life; Link; Malignant - descriptor; Maps; Membrane; Methods; Microbe; Modeling; Molecular; Mucositis; N-terminal; Nucleotides; Oncoproteins; Organism; Outcome; Pathogenicity Island; Pathologic; Peptic Ulcer; Persons; Phenotype; Protein Secretion; Proteins; Research; Resistance; Resolution; Rhizobium radiobacter; Risk Factors; Role; Shapes; Signal Transduction; Stomach; Stomach Diseases; Structural Models; Structure; Structure-Activity Relationship; Symptoms; System; Testing; Time; Type IV Secretion System Pathway; Variant; Virulence Factors; Work; World Health Organization; alpha helix; base; carcinogenesis; fitness; genetic manipulation; improved; in vivo; malignant stomach neoplasm; mutant; particle; periplasm; persistent bacteria; prototype; recruit; response

PROJECT SUMMARY (ABSTRACT) Helicobacter pylori is a Gram-negative bacterium that colonizes the human stomach. H. pylori colonization of the stomach results in chronic gastric mucosal inflammation and is a strong risk factor for gastric cancer and duodenal or gastric ulceration. Gastric cancer is the third leading cause of cancer-related death worldwide, and H. pylori has been classified as a type I carcinogen by the World Health Organization. The H. pylori CagA protein is secreted through a type IV secretion system (T4SS), enters gastric cells, and causes alterations in cellular signaling associated with malignant transformation. CagA and components of the Cag T4SS are encoded by genes within a chromosomal region known as the cag pathogenicity island (PAI), which is present in some H. pylori strains but not others. The incidence of symptomatic gastroduodenal disease (gastric cancer or peptic ulceration) is higher among individuals infected with cag PAI-positive strains than among those infected with cag PAI-negative strains. The molecular architecture and protein composition of the H. pylori Cag T4SS differ substantially from corresponding features of T4SSs found in other bacterial species. The overarching long-term goal of this research is to develop a better understanding of the molecular mechanisms by which H. pylori causes gastric disease. During the previous funding period, we isolated a transmembrane core complex of the Cag T4SS containing five proteins encoded by the cag PAI, described three main structural features of the complex (outer membrane cap, periplasmic ring and stalk), and built partial models of three proteins within the complex. The aims of the current proposal are i) to build a complete structural model of the five Cag T4SS core complex components; ii) to define structure-function relationships for CagY (a core complex component predicted to span from the inner membrane to the outer membrane), elucidating its role in CagA recruitment and T4SS activity; and (iii) to define actions of the Cag T4SS in vivo. Methods will include single particle cryo-electron microscopy analysis of the T4SS core complex, specialized techniques for genetic manipulation of H. pylori, cell culture- based assays of Cag T4SS activity, and an animal model of H. pylori-induced gastric cancer. These studies will provide important advances in our understanding of the molecular mechanisms by which H. pylori infection can lead to gastric cancer and other gastric diseases. On a broader scope, these studies will increase our understanding of bacterial secretion systems and the delivery of bacterial virulence factors into host cells, as well as molecular mechanisms underlying microbe-induced carcinogenesis.

项目概要（摘要） 幽门螺杆菌是一种定植于人类胃中的革兰氏阴性细菌。幽门螺杆菌定植 胃病会导致慢性胃粘膜炎症，是胃癌的强烈危险因素 十二指肠或胃溃疡。胃癌是全球癌症相关死亡的第三大原因，并且 幽门螺杆菌已被世界卫生组织列为I类致癌物。幽门螺杆菌 CagA 蛋白 通过 IV 型分泌系统 (T4SS) 分泌，进入胃细胞，并引起细胞的改变 与恶性转化相关的信号传导。 CagA 和 Cag T4SS 的组件由以下编码 染色体区域内的基因被称为 cag 致病性岛 (PAI)，该岛存在于一些幽门螺杆菌中。 幽门螺杆菌菌株，但不是其他菌株。有症状的胃十二指肠疾病（胃癌或消化道疾病）的发病率 感染 cag PAI 阳性菌株的个体比感染 cag 的个体更高 PAI 阴性菌株。幽门螺杆菌 Cag T4SS 的分子结构和蛋白质组成不同 基本上来自其他细菌物种中发现的 T4SS 的相应特征。总体长期 这项研究的目标是更好地了解幽门螺杆菌引起的分子机制 胃病。在之前的资助期间，我们分离出了 Cag 的跨膜核心复合体 T4SS含有由cag PAI编码的五种蛋白质，描述了该复合物的三个主要结构特征 （外膜帽、周质环和茎），并建立了复合物内三种蛋白质的部分模型。 当前提案的目标是 i) 建立五个 Cag T4SS 核心复合体的完整结构模型 成分; ii) 定义 CagY 的结构-功能关系（一个核心复杂组件，预计将跨越 从内膜到外膜），阐明其在 CagA 募集和 T4SS 活性中的作用； (iii) 定义 Cag T4SS 的体内作用。方法将包括单粒子冷冻电子显微镜 T4SS 核心复合体分析、幽门螺杆菌基因操作的专门技术、细胞培养- 基于 Cag T4SS 活性的测定以及幽门螺杆菌诱导的胃癌动物模型。这些研究将 为我们理解幽门螺杆菌感染的分子机制提供了重要进展 导致胃癌和其他胃病。在更广泛的范围内，这些研究将增加我们的 了解细菌分泌系统和将细菌毒力因子传递到宿主细胞中，如 以及微生物诱发癌变的分子机制。