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利什曼原虫的核苷水解酶(NH)活性来寻找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个国家被认为是发展中国家。据估计，有3.5亿人面临被不同种类的利什曼原虫感染的风险。随着许多沙漠风暴退伍军人接触到沙蝇，这种疾病在美国变得重要起来；2003-2004年，从伊拉克和科威特返回的士兵中报告了大约700例确诊的皮肤利什曼病病例。利什曼病/艾滋病毒混合感染正在成为一种极其严重的新疾病，而且其频率正在增加。利什曼原虫核苷水解酶是安全有效的泛利什曼原虫药物靶点的极佳候选药物。这些问题包括：1)哺乳动物中没有NH活性，2)它在细胞内的位置，3)它在前鞭毛体(由血吸虫和沙蝇传播的感染形式)中的结构性表达。我们将LifePharms的新型天然产物库与MycoLogics的酵母型HTS结合起来，后者包含来自现场采集的担子菌和子囊菌的120,000种半纯化化合物，用于利什曼原虫核苷水解酶(NH)抑制剂。从已筛选的15,000个样品中，我们鉴定出4个化合物对NH具有抑制作用，并在培养中对主要利什曼原虫具有杀灭活性。在这里，我们建议：i)确定分离的先导化合物在体外是否对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对活性化合物进行化学鉴定，iii)使用MycoLogics的专利酵母菌株来筛选另外30,000个样品的体外活性，该酵母菌需要利什曼原虫主要核苷水解酶的活性，以尿苷为尿嘧啶的唯一来源以及利什曼病的体外模型。 公共卫生相关性：利什曼病是热带和亚热带世界大部分地区的重大公共卫生风险。这种疾病在美国具有重要意义，因为由于美国军队在海湾战争中的存在，以及它目前部署到伊拉克和阿富汗，许多士兵被沙蝇叮咬，并出现典型的利什曼病症状。此外，还有一种担忧是，利什曼病可能会在美国变得更加普遍。我们的目标是确定可开发用于有效治疗利什曼病的化合物。

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.