Inhibition of the Nonmevalonate pathway to Kill Mycobacterium tuberculosis

描述（由申请人提供）：本申请涉及广泛的挑战领域（15）转化科学和特定的挑战主题，15-AI-102：开发用于多重或广泛耐药结核病（MDR/XDR TB）的诊断和药物。由结核分枝杆菌（Mycobacterium tuberculosis，Mtb）引起的结核病（tuberculosis，TB）仍然是世界上最致命的传染病之一。与艾滋病毒的合并感染加上耐药菌株的出现使得结核病的治疗既困难又昂贵。为了根除结核病，需要新的药物来杀死结核分枝杆菌的野生型和耐药菌株。开发新的结核病药物的主要挑战是确定细菌生存所需的代谢过程。我们工作的长期目标是了解哪些过程对结核分枝杆菌的生存至关重要。我们将通过开发小分子化学工具来实现这一目标，这些工具可以抑制被认为是重要的特定酶，然后检查它们对细菌存活的影响。随着我们和其他人开发特定生化过程的小分子抑制剂，我们将开始了解哪些途径对细菌生存至关重要。这些途径可以成为治疗干预的目标。该建议集中于开发非甲羟戊酸途径的抑制剂，该途径是类异戊二烯生物合成的初始步骤。这种途径在Mtb中是必需的，但在人类中不存在。我们专注于Dxr，或1-脱氧-D-木酮糖5-磷酸还原异构酶，这是在非甲羟戊酸途径的第一个关键步骤。我们的假设是，Dxr的小分子抑制剂将有效杀死结核分枝杆菌。Dxr抑制剂开发将基于两种方法：（I）合成亲脂性前药和生物电子等排体以增强细胞渗透，以及（II）使用Mtb Dxr和磷霉素（一种已知的Dxr抑制剂）的最新共晶体结构基于结构设计Dxr抑制剂。化合物的活性将通过抑制Mtb Dxr活性以及针对完整Mtb杆菌的功效来评估。从这些研究中，我们将确定Dxr的作用，从而非甲羟戊酸途径，在分枝杆菌的生存，并提供一个平台，进一步铅分子的发展。 公共卫生相关性：结核病（TB）是世界上最致命的传染病之一，同时感染艾滋病病毒和耐药性的出现使结核病的治疗变得既困难又昂贵。为了创造新的结核病药物，我们需要了解如何最好地杀死导致结核病的微生物，结核分枝杆菌。该提案概述了一些实验，这些实验将帮助我们了解是否可以使用一种特定的途径（非甲羟戊酸途径）来杀死这种微生物并帮助治愈结核病。

DESCRIPTION (provided by applicant): This application addresses broad Challenge Area (15) Translational Science and specific Challenge Topic, 15-AI-102: Develop diagnostics and drugs for multiple or extensively drug-resistant tuberculosis (MDR/XDR TB). Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), remains one of the world's deadliest infectious diseases. Co-infection with HIV plus the emergence of drug resistant strains have made TB both difficult and expensive to treat. In order to eradicate tuberculosis, new drugs are needed that will kill wild-type and drug-resistant strains of Mycobacterium tuberculosis. The major challenge in developing new TB drugs is to identify metabolic processes that are required for viability of the bacteria. The long-term goal of our work is to understand which processes are essential for survival of Mycobacterium tuberculosis. We will achieve this through the development of small molecule chemical tools which inhibit specific enzymes thought to be important and then examine their effect on bacterial survival. As we, and others, develop small molecule inhibitors of specific biochemical processes, we will begin to learn which pathways are essential for bacterial survival. These pathways can then become targets for therapeutic intervention. This proposal centers on developing inhibitors of the nonmevalonate pathway, the initial steps in isoprenoid biosynthesis. This pathway is essential in Mtb, but absent in humans. We focus on Dxr, or 1-deoxy-D-xylulose 5-phosphate reducto-isomerase, which is the first committed step in the nonmevalonate pathway. Our hypothesis is that small molecule inhibitors of Dxr will be effective in killing Mycobacterium tuberculosis. Dxr inhibitor development will be based on two approaches: (I) synthesis of lipophilic prodrugs and bioisosteres to enhance cell penetration and (II) structure-based design of Dxr inhibitors using the recent co-crystal structure of Mtb Dxr and fosmidomycin, a known Dxr inhibitor. The activity of compounds will be assessed through inhibition of Mtb Dxr activity, as well as efficacy against intact Mtb bacilli. From these studies, we will determine the role of Dxr, and thereby the nonmevalonate pathway, in mycobacterial survival and provide a platform for further lead molecule development. PUBLIC HEALTH RELEVANCE: Tuberculosis (TB) is one of the world's deadliest infectious diseases, and co-infection with HIV plus the emergence of drug-resistance have made TB both difficult and expensive to treat. In order to create new TB drugs, we need to understand how best to kill the organism that causes TB, Mycobacterium tuberculosis. This proposal outlines experiments that will help us understand if a particular pathway (the nonmevalonate pathway) can be used to kill this organism and help to cure TB.