Establishment of a high throughput screen for the discovery of malaria transmissi

描述（由申请人提供）：建立用于发现疟疾传播阻断药物的高通量筛选，世界范围内疟疾根除计划的主要目标是减少并最终消除疟疾传播。为了实现这一目标，开发预防传播的药物成为高度优先事项，并需要新的方法和测定。在此，我们建议开发一种小分子高通量筛选（HTS），重点是防止配子体的发育，配子体是介导传播的疟疾形式。这项工作的目标是发现可以开发成传播阻断药物的小分子。传统上，疫苗或抗疟药物的开发工作针对恶性疟原虫的无性阶段，而实际上忽略了传播阶段。无性阶段是寄生虫在人类宿主中周期的增殖阶段，并且可以达到大量（体内所有成熟红细胞的20%可能被感染）。无性发育也与恶性疟疾的发病率和死亡率有关。然而，对所有目前使用的药物（所有这些药物都针对无性阶段）的耐药性的出现以及基于无性血液阶段抗原开发疫苗的不成功尝试突出了针对传播阶段的重要性。比尔和梅林达·盖茨基金会于2007年发起的全球根除疟疾运动认识到，如果我们要实现根除目标，就必须将抑制传播作为首要任务。主要的重点是杀虫剂研究以及药物和疫苗，通过杀死血液中的性寄生虫或防止蚊子体内的寄生虫成熟，阻止疟疾从受感染者传播给其他宿主。不幸的是，对传播阶段的生物学知之甚少，与无性阶段寄生虫相比，体外培养和分析的方法有限。本实验室建立了一系列体外标准化培养、检测和定量这些阶段的关键技术。事实上，这些技术使我们能够提出第一个高通量检测方法，其中包含160，000种化学多样性化合物的库，用于发现抑制疟疾传播阶段发展的化合物。该项目是与布罗德研究所的合作，布罗德研究所将提供建立和执行测定以及化合物库的专业知识。这是一个非常重要和及时的项目，具有很大潜力，有助于改善疟疾流行国家的卫生条件。基于在我们拟定的初始化合物浓度下最近的全细胞恶性疟原虫检测的命中率（约1%），我们预计将鉴定出数百至数千种化合物，这些化合物将在剂量降低筛选中进一步研究。此外，我们将对相应的寄生虫表型进行显微镜分析，以确定生长抑制或杀灭的可能常见模式。虽然超出了本奖项拟议的实验范围，但将在后续研究中进一步分析先导化合物，如二次测定、动物研究和通过作用机制研究进行靶点鉴定。这项工作最终将为进一步开发传播阻断药物提供管道，并为我们不断努力了解这些难以捉摸但重要的寄生虫阶段的生物学提供支持。全球疟疾根除计划的一个主要目标是减少并最终消除疟疾传播。为了实现这一目标，开发预防传播的药物成为高度优先事项，并需要新的方法和测定。在此，我们建议开发一种小分子高通量筛选（HTS），重点是防止配子体的发育，配子体是介导传播的疟疾形式。这项工作的目标是发现可以开发成传播阻断药物的小分子。

DESCRIPTION (provided by applicant): Establishment of a high throughput screen for the discovery of malaria transmission blocking drugs a major goal of the worldwide malaria eradication program is the reduction and eventual elimination of malaria transmission. In order to achieve this goal, the development of drugs to prevent transmission becomes a high priority and requires new approaches and assays. Herein we propose to develop a small molecule high throughput screen (HTS) focused on preventing the development of gametocytes, the form of malaria that mediates transmission. The goal of this work is the discovery of small molecules that could be developed into transmission blocking drugs. Efforts for the development of vaccines or antimalarial drugs have traditionally targeted the asexual stages of P.falciparum, while virtually neglecting transmission stages. Asexual stages are the proliferative stages during the parasite cycle in the human host, and can reach large numbers (up to 20% of all mature red blood cells in the body may be infected). Asexual development is also linked to the morbidity and mortality of falciparum malaria. However, the emergence of resistance against all currently used drugs (all of which target asexual stages) and unsuccessful attempts to develop vaccines based on asexual blood stage antigens highlight the importance of targeting transmission stages. The global campaign to eradicate malaria, initiated by the Bill and Melinda Gates foundation in 2007, has recognized that inhibiting transmission needs to be the top priority if we aim for eradication. There is a major focus on insecticide research, as well as on drugs and vaccines designed to block transmission of malaria from an infected person to additional hosts, by killing the sexual form of the parasite in the bloodstream or preventing maturation of the parasite within the mosquito. Unfortunately, little is known about the biology of transmission stages, and methods for in vitro culture and analysis are limited compared to asexual stage parasites. My laboratory has established a series of crucial technologies for the standardized culture, the detection and the quantification of these stages in vitro. In fact, these technologies enable us to propose the first high throughput assay with a library of 160,000 of chemically diverse compounds for the discovery of compounds that inhibit the development of malaria transmission stages. This project is a collaboration with the Broad Institute, which will be providing expertise in establishment and performance of the assay as well as compound libraries. This is a very important and timely project with great potential to contribute to improved health conditions in malaria endemic countries. Based on the hit rate of a recent whole cell P. falciparum assay (approximately 1%) at our proposed initial compound concentration, we anticipate identification of several hundred to a few thousand compounds that will be further investigated in dose-down screens. In addition, we will perform a microscopic analysis of corresponding parasite phenotypes to identify possible common patterns on growth inhibition or killing. Although beyond the scope of the experiments proposed for this award, lead compounds will be further analyzed in follow up studies such as secondary assays, animal studies, and through mechanism of action studies for target identification. This work will ultimately feed both a pipeline for further development of transmission blocking drugs and our continuous efforts to understand the biology of these elusive yet important parasite stages. A major goal of the worldwide malaria eradication program is the reduction and eventual elimination of malaria transmission. In order to achieve this goal, the development of drugs to prevent transmission becomes a high priority and requires new approaches and assays. Herein we propose to develop a small molecule high throughput screen (HTS) focused on preventing the development of gametocytes, the form of malaria that mediates transmission. The goal of this work is the discovery of small molecules that could be developed into transmission blocking drugs.