The function of chemotactic signal transduction during colonization and disease

我们的研究重点是确定TlpC化学受体在调控中的作用机制 引起溃疡的幽门螺杆菌的定植和致病机制。TlpC发挥着重要的作用 在幽门螺杆菌的致病机制中起着令人兴奋的作用，感知宿主乳酸并允许幽门螺杆菌利用它来抵抗 完全不受重视的先天免疫挑战，补体。指导这项工作的中心原则是联合国-- 了解趋化信号将为了解宿主-病原体相互作用的性质提供新的见解。一个GAP重新- 然而，在我们对幽门螺杆菌如何利用乳酸促进补体抵抗的理解中， TlpC整合了乳酸和其他配体的传感，以及TlpC介导的传感在体内如何和在哪里促进 成长。这种差距的持续存在阻碍了我们对幽门螺杆菌致病机理的全面了解 机制，并从长远来看，创造新的药物来阻挠这些过程。全世界数以百万计的人 在美国，人们感染幽门螺杆菌，并患有与之相关的疾病--溃疡和胃癌。 胃癌是全球第四大癌症死亡原因。幽门螺杆菌的存在是基于最近的 研究表明，幽门螺杆菌在发达国家的发病率已经稳定下来。此外，目前的治疗方法 治愈幽门螺杆菌感染失败的频率令人无法接受，例如，美国最近的估计发现 目前的治疗方案无法治愈20-25%的感染者。新的药物靶点是DES- 非常需要。本申请的具体目的是剖析TlpC信号转导和TlpC的作用 它及其感官化合物在胃部定植和疾病中的作用。我们的中心假设是TlpC- 感知化合物在幽门螺杆菌的定植中起着重要作用，并且两者协同作用被感知 TlpC的dCACHE配体结合域结构的亚域。我们的假设是从 用TlpC结晶法分析幽门螺杆菌对乳酸和宿主补体的S反应， 以及测定趋化和TlpC在体内的作用。我们的方法有三个目标，这三个目标结合了H.Py- 洛里分子生物学、小鼠模型和高分辨率蛋白质结晶学。在目标1中，我们剖析了 乳酸在幽门螺杆菌定植中的作用，包括它如何促进生长和补体抵抗。在目标2中，我们 确定幽门螺杆菌TlpC如何将来自多个配体的信息整合到趋化反应中。在AIM 3、我们定义了趋化性如何在活体种群控制中起基础作用。拟议的研究具有创新性，因为它 将创造关于趋化性在细菌致病过程中的功能，复合体的作用的新知识。 以及关于dCACHE配体结合域如何与配体结合的高分辨率信息。 这项拟议的研究具有重要意义，因为无论是在我们对幽门螺杆菌致病机制的理解上，还是在 促进我们对dCACHE配体结合域的理解，dCACHE是最常见的细菌传感模块。 这项研究产生的长期结果可能会提供洞察力，使 治疗幽门螺杆菌相关疾病的新药。

Our proposed research focuses on defining the mechanism of action of the TlpC chemoreceptor in modulating colonization and pathogenesis of the ulcer-causing bacterium Helicobacter pylori. TlpC plays important and exciting roles in H. pylori pathogenesis, sensing host lactate and allowing H. pylori to use it to resist a previ- ously-unappreciated innate immune challenge, complement. The central tenet that guides this work is that un- derstanding chemotaxis signals will lend new insight into the nature of host-pathogen interactions. A gap re- mains, however in our understanding of how H. pylori uses lactate to promote complement resistance, how TlpC integrates lactate and other ligand sensing, and how and where TlpC-mediated sensing promotes in vivo growth. Continued existence of this gap prevents us from gaining a full understanding of H. pylori’s pathogenic mechanisms and, in the long term, creating new drugs to thwart these processes. Millions of people worldwide and in the U.S. are infected by H. pylori and suffer from its associated diseases—ulcers and gastric cancer. Gastric cancer is the fourth highest cause of cancer deaths worldwide. H. pylori is here to stay based on recent studies that show H. pylori incidence has stabilized in the developed world. Furthermore, current therapies to cure H. pylori infection fail with unacceptable frequency, e.g., recent estimates in the United States have found that 20-25% of infected individuals are not cured by the current therapeutic regime. New drug targets are des- perately needed. The specific objective of this application is to dissect TlpC signal transduction and the role of it and its sensed compounds in gastric colonization and disease. Our central hypothesis is that the TlpC- sensed compounds play fundamental roles in H. pylori colonization, and are sensed cooperatively using both subdomains of TlpC’s dCACHE ligand binding domain structure. Our hypothesis has been formulated from preliminary data using crystallization of TlpC, analyzing H. pylori ’s response to lactate and host complement, and determining the role of chemotaxis and TlpC in vivo. Our approach has three Aims, which combine H. py- lori molecular biology, mouse models, and high resolution protein crystallography. In Aim 1, we dissect the role of lactate in H. pylori colonization including how it promotes growth and complement resistance. In Aim 2, we determine how H. pylori TlpC integrates information from multiple ligands into a chemotaxis response. In Aim 3, we define how chemotaxis underlies in vivo population control. The proposed research is innovative in that it will create new knowledge about the functions of chemotaxis during bacterial pathogenesis, the role of comple- ment in the stomach, and high resolution information about how dCACHE ligand binding domains bind ligands. The proposed research is significant because both in our understanding of H. pylori pathogenesis but also for advancing our understanding of dCACHE ligand binding domains, the most common bacterial sensing module. The long-term outcomes generated by this research are likely to provide insights that will enable creation of new drugs against H. pylori-related disease.