Nucleoside hydrolase Inhibitors from natural products for Leishmania

描述（由申请人提供）：我们的目标是通过阻断这种寄生虫的核苷水解酶（NH）活性来确定治疗和化学预防利什曼原虫的新药。利什曼病是一种人畜共患病，影响88个国家的1200万人，其中72个被认为是发展中国家。据估计，有3.5亿人面临感染不同种类利什曼原虫的风险。这种疾病在美国很重要，因为许多沙漠风暴退伍军人接触过沙蝇；2003-2004年从伊拉克和科威特返回的士兵中报告了大约700例皮肤利什曼病确诊病例。利什曼原虫/艾滋病毒合并感染正在成为一种极其严重的新疾病，而且发生频率正在增加。利什曼核苷水解酶是安全有效的泛利什曼药物的极好候选靶点。这些包括i)哺乳动物缺乏NH活性，ii)其细胞内位置，iii)其在promastigotes（由白蛉沙蝇传播的感染形式）中的组成表达。我们将LifePharms的新型天然产物文库与myologics的酵母为基础的HTS结合起来，该文库包括从野外收集的12万种半纯化的承子菌和子囊菌中提取的利什曼核苷水解酶（NH）抑制剂。从已经筛选的15,000个样品中，我们鉴定出4种化合物抑制NH，并对培养的L. major promastigotes具有利什曼尼菌活性。在这里，我们建议i)确定分离的先导化合物是否对体外感染的小鼠和人巨噬细胞有活性，ii)。分离额外数量的先导化合物并化学鉴定活性化合物，iii)使用myologics的专有酵母菌株从LifePharms半纯化合物文库中筛选额外的30,000个样品进行体外活性筛选，该菌株需要利什曼原虫主要核苷水解酶的活性才能在尿嘧啶（尿嘧啶的唯一来源）和利什曼原虫体外模型上生长。

DESCRIPTION (provided by applicant): Our goal is to identify novel drugs for the treatment and chemoprophylaxis of Leishmania by blocking nucleoside hydrolase (NH) activity of this parasite. Leishmaniasis is a zoonosis and affects 12 million people in 88 countries, of which 72 are considered developing countries. It is estimated that 350 million people are at risk to infection by the different species of Leishmania. The disease assumed importance in the United States as many Desert Storm veterans were exposed to sand flies; approximately 700 confirmed cases of cutaneous leishmaniasis were reported in 2003-2004 in soldiers returning from Iraq and Kuwait. Leishmania/HIV co-infection is emerging as an extremely serious, new disease and it is increasing in frequency. The Leishmania nucleoside hydrolase is an excellent candidate as a target for safe and effective pan-Leishmania drugs. These include i) the absence of NH activity in mammals, ii)its intracellular location, iii) and its constitutive expression in promastigotes (the infective form transmitted by phlebotomine sand flies. We combined LifePharms' novel natural product library consisting of 120,000 semipurified compounds from field collected basidiomycetes and ascomycetes with MycoLogics' yeast-based HTS for Leishmania nucleoside hydrolase (NH) inhibitors. From the 15,000 samples already screened, we identified 4 compounds that inhibit NH and are Leishmanicidal active against L. major promastigotes in culture. Here we propose to i) determine if the isolated lead compounds are active against infected mouse and human macrophages in vitro, ii). Isolate additional amounts of lead compound and chemically identify the active compounds, iii) screen an additional 30,000 samples from LifePharms semipure compound library for in vitro activity using a MycoLogics' proprietary strain of yeast that requires the activity of the Leishmania major nucleoside hydrolase for growth on uridine as the sole source of uracil and the in vitro models of leishmaniasis. PUBLIC HEALTH RELEVANCE: Leishmaniasis is a major public health risk throughout much of the tropical and subtropical world. The disease has assumed importance in the United States for due to presence of the US military in the Gulf War and it current deployments to Iraq and Afghanistan many soldiers are bitten by sand flies and develop classic leishmaniasis presentations. Also, there is a concern that leishmaniasis could become more widespread in the United States. Our goal is to identify compounds that can be developed for the effective treatment of Leishmaniasis.