New Therapies for Pathogenic Free-Living Amoebae

描述（由申请人提供）：小型，自由生活的变形虫（FLA）在自然界中无处不在，存在于土壤，淡水和海洋环境中。大多数FLA以细菌为食，没有医学意义，但已知FLA的一些属和种会导致人类和动物严重的，通常是致命的疾病。福氏奈格丽氏杆菌和棘阿米巴属是致病性FLA最著名的例子。福氏奈瑟菌在温暖的淡水中繁殖，是原发性阿米巴脑膜脑炎（PAM）的病原体。这种疾病的特点是一种暴发性、迅速致命的脑病，最常发生在健康的年轻人身上。棘阿米巴更普遍存在于水（淡水和盐水）和土壤中。已知多种棘阿米巴可引起肉芽肿性阿米巴脑炎（GAE），这是一种常见于免疫功能低下宿主和有机会性感染风险者的慢性疾病。棘阿米巴也引起阿米巴角膜炎、皮肤、鼻咽和播散性感染。任何致病性FLA感染的主要问题是缺乏有效的治疗方法。PAM和GAE通常是致命的疾病，即使感染得到及时诊断并使用现有的最佳药物方案进行治疗。尽管FLA引起的感染很严重，但关于新药的数据很少，也没有协调一致的现代药物发现或开发努力。关于FLA药物发现的大多数研究文献都是有限的体外或体内研究，这些研究使用的药物已经被批准用于其他用途。该项目的主要目标是发现先导化合物，用于开发治疗致病性FLA中枢神经系统感染的药物。我们将通过筛选一个大型文库（<1100）生物活性药物来确定治疗FLA的新化学型来实现这些目标。此外，我们将开发新的体外药敏试验适用于高通量筛选，以支持这些研究目标。最后，我们将采用一种模拟血脑屏障的新型微流体装置来研究致病性FLA的感染动力学，并评估本提案中发现的新化合物的杀伤率。

DESCRIPTION (provided by applicant): Small, free-living amoebae (FLA) are ubiquitous in nature and are found in soil, fresh water, and marine environments. Most of the FLA feed on bacteria and are of no medical importance, yet several genera and species of FLA are known to causes serious, usually fatal disease in humans and animals. Naegleria fowleri and Acanthamoeba spp. are the best known examples of pathogenic FLA. N. fowleri thrives in warm, freshwater and is the causative agent of primary amoebic meningoencephalitis (PAM). This disease is characterized by a fulminant, rapidly fatal encephalitic disease that most often afflicts healthy young humans. Acanthamoeba spp. are more ubiquitous and found in water (fresh and saline) and soil. Multiple species of Acanthamoeba are known to cause granulomatous amoebic encepahalitis (GAE), a chronic disease seen most often in immunocompromised hosts and those at risk of opportunistic infections. Acanthamoeba spp. also causes amoebic keratitis, skin, nasopharyngeal, and disseminated infections. The major problem for infections with any of the pathogenic FLA is the lack of effective therapeutics. PAM and GAE are usually fatal diseases, even if the infection is diagnosed promptly and treated with the best available drug regimens. Despite the severity of infections caused by FLA, there are few data available on new drugs and no concerted modern drug discovery or development efforts. The majority of the research literature on drug discovery for FLA consists of limited in vitro or in vivo studies with drugs already approved for other uses. The major goals of this project are to discover lead compounds for development as drugs to treat the central nervous system infections with pathogenic FLA. We will achieve these goals by screening a large library (<1100) bioactive drugs to identify novel chemotypes for the treatment of FLA. In addition, we will develop new in vitro drug susceptibility assays amenable for high throughput screening to support these research goals. Finally, we will adapt a novel microfluidics device that mimics the blood brain barrier to study the infection dynamics of pathogenic FLA and to assess the rate of killing of new compounds discovered in this proposal.