Evaluation of marketed drugs for rapid development as anti-cryptosporidal agents

描述(申请人提供)：微小隐孢子虫是一种艾滋病OI病原体和B类病原体，可导致人和动物严重的水样腹泻。这种寄生虫可以在免疫功能受损的人中引起长期的、危及生命的感染，并对艾滋病患者的相当程度的发病率和死亡率负责。此外，由于感染性卵囊对化学胁迫具有高度的抵抗力，微小隐孢子虫是一种重要的水。 和食源性病原体，以及NIH生物防御计划中的B类病原体之一。目前，没有一种药物被FDA批准用于治疗免疫功能低下患者的隐孢子虫病，尽管在美国有一种药物(硝唑尼特)被批准用于免疫功能正常的患者。因此，迫切需要开发新的抗隐孢子虫药物，特别是针对艾滋病患者的新药。受“改变现有药物用途”以达到潜在新适应症的最新发展，以及我们出人意料地观察到标记药物在体外可强烈抑制隐孢子虫的生长，我们计划通过筛选所有现有药物在体外和体内的潜在抗隐孢子虫活性来扩大我们的发现。简而言之，我们将利用已建立的模型和方法来实现以下两个目标：目的1.利用我们完善和改进的qRT-PCR方法在体外从已知药物中鉴定潜在的抗隐孢子虫化合物。目的2.采用小鼠隐孢子虫急性感染和慢性感染模型，确定所选药物的体内抗隐孢子虫效果。正在筛选的大多数化合物都是目前或以前上市的药物。拟议的实验检验了药物在体外和体内对寄生虫生长的直接影响。因此，如果FDS批准的任何一种药物在体内外都表现出良好的抗隐孢子虫活性，这些有效的药物就可以迅速进入临床试验，并被重新用于治疗人类隐孢子虫感染的新药，从而加速针对隐孢子虫的药物的发现和开发。此外，该项目仍将产生大量数据，概述几乎所有现有和废弃药物的活动情况。这些宝贵的数据可以用来分析隐孢子虫的构效关系，以指导未来的药物开发。

DESCRIPTION (provided by applicant): Cryptosporidium parvum is an AIDS-OI pathogen and Category B agent that can cause severe watery diarrhea in humans and animals. This parasite can cause prolonged, life threatening infection in immunocompromised individuals, and is responsible for a substantial degree of morbidity and mortality in AIDS patients. Also because the infectious oocysts are highly resistant to chemical stresses, C. parvum is a significant water- and food-borne pathogen and one of the category B agent in the NIH biodefense program. Currently, no drug is FDA-approved to treat cryptosporidiosis in immunocompromised patients, although a single drug (nitazoxanide) is approved for use in immunocompetent patients in the United States. Therefore, there is an urgent need to develop new anti-Cryptosporidium drugs, particularly new drugs for AIDS patients. Encouraged by the recent development in "repurposing of existing drugs" for potential new indications, as well as based on our unexpected observations that a marked drug could strongly inhibit the growth of Cryptosporidium in vitro, we plan to extend our discovery by screening all existing drugs for their potential ant-cryptosporidia activities in vitro and in vivo. Briefly, we will take advantage of established models and assays t achieve the following two aims: Aim 1. To identify potential anti-cryptosporidial compounds from known drugs in vitro using our well- developed and improved qRT-PCR assay. Aim 2. To determine anti-cryptosporidial efficacy of select drugs in vivo using acute and chronic mouse models of cryptosporidial infection. The majority of the compounds being screened are currently or previously marketed drugs. The proposed experiments examine the direct effects of drugs on the parasite growth in vitro and in vivo. Therefore, if satisfactory anti-cryptosporidial activitie in vitro and in vivo are observed among any of the FDS-approved drugs, these effective drugs can be rapidly moved to clinical trials and repurposed to become new drugs to treat cryptosporidial infection in humans, thus accelerating the drug discovery and development against Cryptosporidium. Furthermore, the project will nonetheless produce a large amount of data that profiles the activities of nearly all existing and abandoned drugs. The invaluable data can be used to analyze the structure-activity relationship (SAR) against Cryptosporidium to guide future drug development.