ASSESSING IN VITRO/VIVO EFFICACY OF ANTIMALARIAL ENR INHIBITORS

在热带地区，由恶性疟原虫感染引起的疟疾对人类健康造成巨大损害。目前的抗疟疾治疗受到对氯喹（干扰血红素解毒）和乙胺-磺胺多辛（抑制叶酸生物合成）具有耐药性的恶性疟原虫菌株的传播的严重影响。几个研究小组最近确定了恶性疟原虫II型脂肪酸合成（FAS-II），这是一种人类缺乏的顶质体途径，是一种独特的药物靶点。FAS-II酶烯丙基ACP还原酶（ENR）是三氯生、异烟肼和乙硫酰胺等几种广泛使用的抗菌药物的靶点。我们的项目代表了葛兰素史克、德克萨斯A&M大学和阿尔伯特·爱因斯坦医学院之间的公共/私营合作伙伴关系，提议实施针对纯化恶性疟原虫ENR （ppfenr）的高通量筛选，并随后进行结合化学、生物化学、结构生物学、分子生物学和寄生虫学的Hits to Leads项目。在本项目的目的1中，我们将评估试验ENR抑制剂对耐药的疗效

Malaria caused by infection with Plasmodium falciparum exerts an enormous toll on human health in tropical regions. Current antimalarial treatments are being severely compromised by the spread of P. falciparum strains resistant to chloroquine (that interferes with heme detoxification) and pyrimethamine-sulfadoxine (that inhibits folate biosynthesis). Several groups have recently defmed P. falciparum type II fatty acid synthesis (FAS-II), an apicoplast pathway that is lacking in humans, as a unique drug target. The FAS-II enzyme enoyl ACP reductase (ENR) is the target of several widely used antimicrobial agents including triclosan, isoniazid and ethionamide. Our Program, representing a public/private partnership between GlaxoSmithKline, Texas A&M University and the Albert Einstein College of Medicine, proposes to implement a high throughput screen against purified P. falciparum ENR (PfENR) and follow this with a Hits to Leads program that integrates chemistry, biochemistry, structural biology, molecular biology and parasitology. In Aim 1 of this project, we will evaluate the efficacy of test ENR inhibitors against drug-resistant and drug-sensitive P. falciparum in vitro. Aim 2 will assess the in vivo efficacy of promising PfENR inhibitors, using non-transformed P. berghei as well as transgenic P. berghei clones expressing the enoyl ACP reductase from P. falciparum or P. vivax (the second most important human malaria species) in the place of the rodent malarial enzyme (the transgenic P. berghei lines will be generated as part of Project 3). Aim 3 proposes to develop transgenic, "mode of action" P. falciparum lines that underexpress PfENR or are functionally complemented for ENR activity, to assess inhibitor specificity. Aim 4 will develop a transgenic P. falciparum line expressing the P. vivax enr in the place of pfenr, as a surrogate model to measure in vitro activity against P. vivax. This project provides key resources and reagents to identify potent, orally bioavailable inhibitors that can move down the critical path and enter preclinical development as new candidate antimalarial drugs.