Molecular Mechanisms of the H. pylori Vacuolating Toxin

幽门螺杆菌空泡毒素的分子机制

基本信息

批准号：
8136829
负责人：
Steven R. Blanke
金额：
$ 5.87万
依托单位：
UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-09-20 至 2011-05-31
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): Persistent infection with Helicobacter pylori is a significant risk factor for a number of gastric disorders in humans, including peptic ulceration and gastric adenocarcinomas. The vacuolating cytotoxin (VacA) is an important virulence factor that mounting evidence indicates is involved in multiple aspects of H. pylori-mediated colonization and persistence. The broad objective of this research program is to identify how the cellular modulating activities of VacA contribute to the pathogenesis strategies of H. pylori within the host. In this application, we propose to explore two important aspects of VacA cellular intoxication. In Specific Aim 1, we propose experiments to investigate the mechanism underlying recent observations that VacA induces caspase-dependent programmed cell death in a mitochondrial-dependent manner. In Specific Aim 1, we will explore the overall hypothesis that VacA localizes to mitochondria and elaborates a biochemical activity that modulates mitochondrial membrane permeability. We will test a number of predictions of this hypothesis related to the mechanism of VacA-induced changes in membrane permeability, and how these changes relate to downstream consequences within the cell. Moreover, we will test the prediction that VacA is "hard-wired" with sequences or motifs to target the toxin to mitochondria and then engage existing mitochondrial import machinery. In these studies, we will employ both cultured cell lines, as well as isolated mitochondria. The proposed experiments are important for revealing aspects of an emerging strategy used by several pathogens to directly target mitochondria as a strategy for modulating host cell death. In Specific Aim 2, we will explore the interactions of VacA with specialized microdomains of the plasma membrane of target cells that have been demonstrated to be important for cellular activity. We will explore the overall hypothesis that VacA associates with and functionally lipid rafts on the plasma membrane of target host cells. In this Aim, we will investigate the dependency of different VacA cellular activities on lipid rafts, as well as the functional relationship between lipid rafts and a known receptor for VacA. We will then explore how the lipid composition affects VacA association with rafts. Finally, we will identify and characterize VacA sequences and/or motifs that promote binding to lipid rafts. These studies will reveal novel aspects of the mechanisms underlying cellular intoxication, as well as new approaches for blocking cellular intoxication. Because it is estimated that the prevalence of H. pylori infection in developed countries is 20-50%, and 70-90% in developing countries, the importance of developing efficacious vaccines, chemotherapeutics, and diagnostics for H. pylori cannot be overstated. These studies will not only contribute to our understanding of the fundamental mechanisms of VacA-mediated cytotoxicity, but may reveal novel strategies for blocking or minimizing the consequences of VacA-mediated cellular intoxication during infection.

描述（由申请人提供）：幽门螺杆菌的持续感染是人类许多胃部疾病的重要危险因素，包括消化性溃疡和胃腺癌。空泡细胞毒素 (VacA) 是一种重要的毒力因子，越来越多的证据表明它参与幽门螺杆菌介导的定植和持久性的多个方面。该研究计划的总体目标是确定 VacA 的细胞调节活性如何促进宿主内幽门螺杆菌的发病机制。在此应用中，我们建议探索 VacA 细胞中毒的两个重要方面。在具体目标 1 中，我们提出实验来研究最近观察到的 VacA 以线粒体依赖性方式诱导 caspase 依赖性程序性细胞死亡的机制。在具体目标 1 中，我们将探讨 VacA 定位于线粒体并阐述调节线粒体膜通透性的生化活性的总体假设。我们将测试该假设的一些预测，这些预测与 VacA 诱导的膜通透性变化的机制有关，以及这些变化与细胞内下游后果的关系。此外，我们将测试 VacA 与序列或基序“硬连线”的预测，将毒素靶向线粒体，然后参与现有的线粒体输入机制。在这些研究中，我们将使用培养的细胞系以及分离的线粒体。所提出的实验对于揭示几种病原体使用的直接靶向线粒体作为调节宿主细胞死亡的策略的新兴策略的各个方面非常重要。在具体目标 2 中，我们将探索 VacA 与靶细胞质膜特殊微域的相互作用，这些微域已被证明对细胞活动很重要。我们将探讨 VacA 与靶宿主细胞质膜上的脂筏相关并具有功能性的总体假设。在这个目标中，我们将研究不同的 VacA 细胞活性对脂筏的依赖性，以及脂筏和已知的 VacA 受体之间的功能关系。然后我们将探讨脂质成分如何影响 VacA 与筏的关联。最后，我们将鉴定和表征促进与脂筏结合的 VacA 序列和/或基序。这些研究将揭示细胞中毒机制的新方面，以及阻止细胞中毒的新方法。据估计，发达国家的幽门螺杆菌感染率为 20-50%，发展中国家为 70-90%，因此开发有效的幽门螺杆菌疫苗、化疗和诊断方法的重要性怎么强调也不为过。这些研究不仅有助于我们了解 VacA 介导的细胞毒性的基本机制，而且可能揭示在感染过程中阻断或最小化 VacA 介导的细胞中毒后果的新策略。

项目成果

期刊论文数量（21）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Remodeling the host environment: modulation of the gastric epithelium by the Helicobacter pylori vacuolating toxin (VacA).

DOI：
10.3389/fcimb.2012.00037
发表时间：
2012
期刊：
Frontiers in cellular and infection microbiology
影响因子：
5.7
作者：
Kim IJ;Blanke SR
通讯作者：
Blanke SR

Host cell sensing and restoration of mitochondrial function and metabolism within Helicobacter pylori VacA intoxicated cells.

DOI：
10.1128/mbio.02117-23
发表时间：
2023-10-31
期刊：
MBIO
影响因子：
6.4
作者：
Seeger, Ami Y.;Zaidi, Faisal;Alhayek, Sammy;Jones, Rachel M.;Zohair, Huzaifa;Holland, Robin L.;Kim, Ik-Jung;Blanke, Steven R.
通讯作者：
Blanke, Steven R.

Functional complementation reveals the importance of intermolecular monomer interactions for Helicobacter pylori VacA vacuolating activity.

功能互补揭示了分子间单体相互作用对于幽门螺杆菌 VacA 空泡活性的重要性。

DOI：
10.1046/j.1365-2958.2002.02818.x
发表时间：
2002
期刊：
Molecular microbiology
影响因子：
3.6
作者：
Ye,Dan;Blanke,StevenR
通讯作者：
Blanke,StevenR

Helicobacter pylori Infection Modulates Host Cell Metabolism through VacA-Dependent Inhibition of mTORC1.

DOI：
10.1016/j.chom.2018.04.006
发表时间：
2018-05-09
期刊：
Cell host & microbe
影响因子：
30.3
作者：
Kim IJ;Lee J;Oh SJ;Yoon MS;Jang SS;Holland RL;Reno ML;Hamad MN;Maeda T;Chung HJ;Chen J;Blanke SR
通讯作者：
Blanke SR

Modification of a mammalian cell protein in the presence of [32P-adenylate]NAD: evidence for ADP ribosylation activity associated with Helicobacter pylori.

[32P-腺苷酸]NAD 存在下哺乳动物细胞蛋白的修饰：ADP 核糖基化活性与幽门螺杆菌相关的证据。