Inhibition of MEP pathway Isoprenoid Biosynthesis

 描述(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混合感染，加上世界各地出现许多耐药菌株，使这些感染难以治疗，治疗成本也很高。需要新的药物来杀死这两种生物的野生型和抗药性菌株。开发新的抗菌剂的主要挑战是确定既是生存所需的代谢过程，又能够成为小分子的靶点。我们的总体目标是 工作是发现和开发新的、有效的抗结核病和抗疟疾药物。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点。该提案以1-脱氧-D-木酮糖-5-磷酸还原异构酶(Dxr)为抗菌药物靶点。Dxr是甲基赤藓糖醇磷酸(MEP，又名非甲戊酸)合成异戊二烯的第一个步骤，也是一个限速步骤。Dxr和MEP是结核分枝杆菌和恶性疟原虫生存所必需的，而这一途径在人类中是不存在的。目前的抗菌药物不能通过Dxr(或MEP)机制起作用。开发Dxr抑制剂作为对抗结核病和疟疾的先导化合物将具有治疗价值。我们以前的工作已经产生了几个化合物系列，它们有效地抑制Dxr，杀死感染Mtb和恶性疟原虫的细胞，作用于靶点，并在小鼠中杀死疟原虫感染。拟议的实验旨在进一步提高我们化合物的有效性，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，我们将在前期工作的基础上，合成一系列新颖、设计合理的膦酸类化合物。为了提高细胞渗透率，还将合成亲脂性前药酯。其次，将评估化合物对来自结核分枝杆菌和恶性疟原虫的纯化重组Dxr的抑制作用和结合方式。第三，我们将测量我们的化合物对野生型和抗药性菌株的抗菌活性。我们将确认这些化合物在细胞内的靶向效应。最有希望的化合物将在药代动力学(PK)和动物疗效分析中进行评估。总体而言，这项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微生物化合物，并可能为进一步的铅分子开发提供平台。

 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.