Inhibition of MEP pathway Isoprenoid Biosynthesis

 描述（由申请人提供）：由结核分枝杆菌（Mtb）引起的结核病（TB）和由恶性疟原虫引起的疟疾仍然是世界上最致命的传染病之一。与艾滋病毒等其他疾病的合并感染，加上世界各地出现的许多耐药菌株，使这些感染难以治疗，治疗费用高昂。需要新的药物来杀死这两种生物体的野生型和耐药菌株。在开发新的抗菌剂的主要挑战是要确定代谢过程，都需要的活力和能够被小分子的目标。我们的总体目标是 工作是发现和开发新的、有效的抗结核和抗疟疾药物。我们将通过将细胞内作用于靶点的有效小分子抑制剂的合成与下游药代动力学和动物实验相结合来实现这一目标。 该提议以1-脱氧-D-木酮糖5-磷酸还原异构酶（Dxr）为中心作为抗微生物药物靶标。Dxr是类异戊二烯生物合成的磷酸甲脂（MEP，又名非甲羟戊酸）途径中的第一个关键步骤和限速步骤。Dxr和MEP对于Mtb和恶性疟原虫的存活是必需的，并且该途径在人类中不存在。目前的抗微生物药物不通过Dxr（或MEP）机制起作用。开发Dxr抑制剂作为抗结核病和疟疾的先导化合物将具有治疗价值。我们先前的工作已经产生了几种化合物系列，它们有效地抑制Dxr，杀死Mtb和恶性疟原虫感染的细胞，在细胞内作用于靶标，并杀死小鼠中的疟原虫感染。所提出的实验旨在进一步提高我们的化合物的功效，验证Dxr抑制的细胞内效应，并评估最有效的抑制剂的治疗潜力。 首先，在前人工作的基础上，我们将合成一系列新的、设计合理的膦酸。为了改善细胞渗透，还将合成亲脂性前药酯。其次，将评估化合物对来自Mtb和恶性疟原虫的纯化重组Dxr的抑制和结合模式。第三，我们将测量我们的化合物对野生型和耐药菌株的抗菌活性。我们将确认化合物的细胞内靶向作用。最有前途的化合物将在药代动力学（PK）和动物功效测定中进行评估。 总体而言，本提案中概述的实验将产生针对结核分枝杆菌和恶性疟原虫的有效抗菌化合物，并可能为进一步开发先导分子提供平台。

 DESCRIPTION (provided by applicant): Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), and malaria, caused by Plasmodium falciparum, remain amongst the world's deadliest infectious diseases. Co-infection with other diseases such as HIV plus the emergence of many drug-resistant strains worldwide have made these infections difficult and costly to treat. New drugs are needed that will kill wild-type and drug-resistant strains of both organisms. The major challenge in developing new antimicrobial agents is to identify metabolic processes that are both required for viability and able to be targeted by small molecules. The overall goal of our work is to discover and develop novel, potent antitubercular and antimalarial agents. We will achieve this by coupling the synthesis of potent small molecule inhibitors acting on-target intracellularly with downstream pharmacokinetic and animal experiments. This proposal centers on 1-deoxy-D-xylulose 5-phosphate reductoisomerase (Dxr) as an antimicrobial drug target. Dxr is the first committed, and a rate-limiting step in the methylerythritol phosphate (MEP, aka nonmevalonate) pathway of isoprenoid biosynthesis. Dxr and MEP are essential for Mtb and P. falciparum survival, and the pathway is absent in humans. Current antimicrobial drugs do not work through a Dxr (or MEP) mechanism. Development of Dxr inhibitors as lead compounds against TB and malaria would be therapeutically valuable. Our prior work has resulted in several compound series that potently inhibit Dxr, kill both Mtb and P. falciparum-infected cells, act on-target intracellularly, and kill Plasmodium infection in mice. The proposed experiments are designed to further improve the efficacy of our compounds, verify the intracellular effects of Dxr inhibition, and evaluate the therapeutic potential of the most potent inhibitors. First, based on the success in our prior work, we will synthesize a series of novel, rationally-designed phosphonic acids. To improve cell penetration, lipophilic prodrug esters will also be synthesized. Second, compounds will be assessed for inhibition and mode of binding against purified recombinant Dxr from Mtb and P. falciparum. Third, we will measure the antimicrobial activity of our compounds against wild-type and drug-resistant strains. We will confirm the intracellular, on-target effects of the compounds. The most promising compounds will be evaluated in pharmacokinetics (PK) and animal efficacy assays. Overall, the experiments outlined in this proposal will result in potent antimicrobial compounds against both Mtb and P. falciparum and may provide a platform for further lead molecule development.