Molecular Mechanisms of the H. pylori Vacuolating Toxin

幽门螺杆菌空泡毒素的分子机制

• 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
• 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
• 来源: https://reporter.nih.gov/project-details/8136829
• 关键词: Affect; Apoptosis; Binding; Biochemical; Caspase; Cell Death; Cell Line; Cell Membrane Permeability; Cell membrane; Cells; Cytotoxin; Dependency; Developed Countries; Developing Countries; Diagnostic; Disease; Gastric Adenocarcinoma; Helicobacter Infections; Helicobacter pylori; Human; Infection; Intoxication; Lipids; Mammalian Cell; Mediating; Membrane Microdomains; Mitochondria; Molecular; Pathogenesis; Pathology; Prevalence; Property; Research; Risk Factors; Stomach; Targeted Toxins; Testing; Toxin; Ulcer; Vaccines; Virulence Factors; cytotoxicity; mitochondrial membrane; novel; novel strategies; pathogen; programs; receptor; research study

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（由申请方提供）：幽门螺杆菌持续感染是人类多种胃部疾病的重要危险因素，包括消化性溃疡和胃腺癌。空泡毒素（VacA）是H.幽门介导的定植和持久性。本研究计划的主要目的是确定VacA的细胞调节活动如何有助于H.宿主体内的幽门螺杆菌。在这个应用中，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，我们提出了实验来研究最近的观察，VacA诱导半胱天冬酶依赖的程序性细胞死亡的细胞依赖性方式的机制。在具体目标1中，我们将探讨整体假设，即VacA定位于线粒体，并阐述了调节线粒体膜通透性的生化活性。我们将测试这个假设的一些预测与VacA诱导的膜通透性变化的机制，以及这些变化如何与细胞内的下游后果。此外，我们将测试VacA与序列或基序“硬连线”的预测，以将毒素靶向线粒体，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。所提出的实验是重要的，揭示了一些病原体使用的一种新兴的策略，直接靶向线粒体作为调节宿主细胞死亡的策略。在具体目标2中，我们将探索VacA与靶细胞质膜的专门微区的相互作用，这些微区已被证明对细胞活性很重要。我们将探讨整体假设，VacA与靶宿主细胞质膜上的脂筏相关，并在功能上起作用。在这个目标中，我们将调查不同的VacA细胞活动对脂筏的依赖性，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，我们将确定和表征VacA序列和/或基序，促进结合脂筏。这些研究将揭示细胞中毒机制的新方面，以及阻断细胞中毒的新方法。据估计，H.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，开发有效的疫苗、化疗药物和诊断方法对于幽门螺杆菌的感染具有重要意义。幽门螺杆菌不能被夸大。这些研究不仅有助于我们理解VacA介导的细胞毒性的基本机制，而且可能揭示在感染期间阻断或最小化VacA介导的细胞中毒后果的新策略。

项目成果

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.

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

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

Sphingomyelin functions as a novel receptor for Helicobacter pylori VacA.

鞘磷脂充当幽门螺杆菌VACA的新型受体。

• DOI: 10.1371/journal.ppat.1000073
• 发表时间: 2008-05-23
• 期刊: PLOS PATHOGENS
• 影响因子: 6.7
• 作者: Gupta, Vijay R.;Patel, Hetal K.;Kostolansky, Sean S.;Ballivian, Roberto A.;Eichberg, Joseph;Blanke, Steven R.
• 通讯作者: Blanke, Steven R.