The role of ArsS in gastric infection by Helicobacter pylori

 描述(申请人提供)：幽门螺杆菌定植在正常的胃酸分泌约50%的世界人口。定植与胃病有关，包括胃炎、消化性和十二指肠溃疡、胃癌和MALT淋巴瘤。虽然三联疗法最初的根治率是成功的(~95%)，但抗生素耐药性使感染的成功治疗逐渐变得更加困难。因此，迫切需要一种不含抗生素的替代根除单一疗法。幽门螺杆菌特有的、节省的共生肠道菌群或抗生素治疗的改进，以减少治疗的持续时间和复杂性。这项研究的长期目标是了解幽门螺杆菌对胃酸的反应和存活情况，并利用这一知识开发新的治疗方案和/或改进当前的根除疗法。本研究的目的是确定酸敏感的双组分系统(TCS)ArsRS如何调节酸诱导的尿素酶及其附属蛋白向内膜转运，以形成与UreI结合的膜复合体，这是胃部感染和酸生存所必需的。这项研究的基本原理是，了解ARS使用的机制将允许进行药物干预，从而产生新的针对幽门螺杆菌的、不含抗生素的单一疗法和/或改进当前的根除方案。其具体目的是：1.阐明传感器蛋白激酶ArsS介导的酸诱导信号转导机制。由于ArsS对胃的定植和酸生存是必不可少的，了解蛋白质转运到UreI的机制和UreI/尿素酶膜复合体的形成将提供新的清除靶点。2.鉴定依赖酸的膜蛋白质组以及ArsS对鉴定的蛋白质在细菌内转运中的作用。这一细菌内蛋白质贩运的非凡例子为开发抗感染药物提供了一个独特的机会。3.确定高 高通量筛选(HTS)亲和ArsS抑制剂由于ArsS的酸敏感域位于周质，而ArsS对胃感染是必需的，因此它是一个有吸引力的根除靶点。我们已经设计了一种HTS，它将允许检测在ArsS和UreI之间选择的抑制剂。AIMS 1和AIMS 2的工作将使用生化和分子生物学技术来识别负责维持幽门螺杆菌胃定植的蛋白质和调控途径。AIM 3中建议的工作将提供先导化合物，使胃感染所需的ArsRS信号级联失活。这三个目标的结果将通过提供新的目标和改进现有的根除疗法而产生重要的积极影响。

 DESCRIPTION (provided by applicant): Helicobacter pylori colonizes the normal acid-secreting stomach of about 50% of the world's population. Colonization is associated with gastric disease, including gastritis, peptic and duodenal ulcers, gastric carcinoma, and MALT lymphoma. Although initial eradication rates with triple therapy were successful (~95%), antibiotic resistance has made successful treatment of infection progressively more difficult. Thus, there is a critical need for an antibiotic-free alternative eradication mono-therapy that is . pylori-specific, sparing commensal gut flora or improvement to antibiotic therapy that decreases the duration and complexity of treatment. The long-term goal of this study is to understand how H. pylori responds to and survives gastric acidity and exploit this knowledge to develop novel treatment regimens and/or improve current eradication therapies. The objective here is to determine how the acid-sensitive Two-Component System (TCS), ArsRS, regulates the acid-induced trafficking of urease and its accessory proteins to the inner membrane to form a membrane- bound complex with UreI that is required for gastric infection and acid survival. The rationale for the study is that understanding the mechanisms used by ArsS will allow pharmacological interference resulting in new H. pylori-specific antibiotic-free monotherapy and/or improvement in current eradication regimens. The specific aims are: 1. Elucidate the acid-induced signaling mechanism mediated by the sensor kinase ArsS. Because ArsS is essential for gastric colonization and acid survival, knowing the mechanism of protein trafficking to UreI and the formation of the UreI/urease membrane complex will provide novel eradication targets. 2. Identify the acid-dependent membrane proteome and the contribution of ArsS to intrabacterial trafficking of the identified proteins. This remarkable example of intra-bacterial protein trafficking provides a unique opportunity to develop anti-infective drugs. 3. Identify high affinity ArsS inhibitors by High- Throughput Screening (HTS). Because the acid-sensing domain of ArsS is in the periplasm and ArsS is essential for gastric infection, it is an attractive eradication target. We have designed an HTS that will allow detection of inhibitors that select between ArsS and UreI. The work of aims 1 and 2 will use biochemical and molecular biological techniques to identify proteins and regulatory pathways responsible for maintenance of gastric colonization by H. pylori. The work proposed in aim 3 will provide lead compounds that inactivate the ArsRS signaling cascade required for gastric infection. The results of these three aims will have an important positive impact by providing novel targets and improving current therapies for eradication.