Development of novel therapeutics for a neglected tropical disease leishmaniasis

描述(由申请人提供)：本申请响应RFA-OD-10-005，涉及RFA的两个主题领域：全球健康和将基础科学发现转化为新的更好的治疗方法。利什曼原虫通过沙蝇媒介传播，是一种专性细胞内寄生虫，可引起多种疾病，包括皮肤(CL)、粘膜皮肤(MCL)和内脏利什曼病(VL)。目前有1200多万人患有利什曼病，每年约有200万新病例发生，使其成为一个重大的全球卫生问题和世卫组织被列为被忽视的热带疾病。最近，这种疾病越来越多地出现在美国的犬类种群中，以及在利什曼原虫流行国家(如伊拉克和阿富汗)服役的军队人员。锑(GLucantime(Tm)和Pentostam(Tm))、两性霉素B和米替福辛被用于治疗利什曼病。不幸的是，这些药物是有毒的，患者依从性很差，因为其中许多药物需要全身给药3-5周，而且全球耐药菌株的出现正在迅速增加。因此，迫切需要安全、廉价、易于管理、对不同种类利什曼原虫具有广谱活性的新药。在尤卡坦半岛，玛雅传统治疗师多年来一直使用五倍子的根来局部治疗CL，表明五倍子含有抗利什曼分子，可能是潜在的治疗利什曼病的新药。我们发现山竹根正己烷提取物(PARE)在体外和体内均具有较强的抗利什曼病活性。PARE在体外杀死利什曼原虫的效率与GLucantime(Tm)一样高，而且对细胞内寄生虫也很有效。我们的初步数据表明，用PARE局部治疗也能有效地限制小鼠的墨西哥乳杆菌感染。我们正在进行的R21项目中的工作(从五叉神经酮中分离新的抗利什曼分子；AI07639-01A1；A.Satoskar，研究员，A.D.Kinghorn，共同研究员)已经导致在PARE中鉴定出几个具有利什曼杀菌活性的化合物，包括两个新的甾醇。预计在2010年8月R21项目完成之前，将从该工厂分离出更多的生物活性分子。这项针对RFA-OD-10-005的应用是为了扩展我们正在进行的研究，并对从植物Pandrieuxii和Mycoynthetix Inc.的真菌中分离的抗利什曼分子进行临床前测试。在目标1中，我们将从植物的不同成分中分离出抗利什曼分子并确定其来源(S)。AIM 2将使用动物模型来评估这些植物来源的分子以及真菌来源的分子在治疗不同形式的利什曼病以及由对传统药物产生抗药性的寄生虫引起的VL方面的安全性和有效性。目标3将确定在我们的动物研究中活跃的分子的作用机制(S)。由于在利什曼病(Satoskar)、植物化学(Kinghorn)、合成化学(Fuchs)和真菌学/内生真菌(Pearce)方面的互补专业知识，我们的团队准备进行这些研究。我们的研究应该确定Pandrieuxii中的生物活性分子如何介导抗利什曼活性，并提供关于它们治疗利什曼原虫感染的安全性和有效性的信息，这些感染株对常规治疗具有耐药性。总之，这些数据将为推进未来对这些分子的临床研究奠定基础，以便更好地治疗各种形式的利什曼病。 公共卫生相关性：由细胞内原生动物寄生虫利什曼原虫引起的感染是一个主要的全球健康问题，抗药性寄生虫的出现在世界范围内迅速增加。该项目的总体目标是从植物五羟色胺中发现新的抗利什曼药物，用于治疗不同形式的利什曼病。

DESCRIPTION (provided by applicant): This application in response to RFA-OD-10-005 addresses two thematic areas from the RFA, Global Health and Translating Basic Science Discoveries into New and Better Treatments. Transmitted by sand fly vectors, Leishmania are obligate intracellular parasites that cause a wide range of diseases, including cutaneous (CL), mucocutaneous (MCL) and visceral leishmaniasis (VL). Over 12 million people currently suffer from leishmaniasis, and approximately 2 million new cases occur each year, making it a major global health problem and a WHO classified neglected tropical disease. Recently, this disease is increasingly seen in canine populations in the US, as well as army personnel serving in Leishmania endemic countries such as Iraq and Afghanistan. Antimonials (Glucantime(tm) and Pentostam(tm)), amphotericin B, and miltefosine are used to treat leishmaniasis. Unfortunately these drugs are toxic and have poor patient compliance because many of them require systemic administration for periods ranging from 3-5 wks, and the emergence of drug-resistant strains is rapidly increasing worldwide. Therefore, there is a strong need for new drugs which are safe, cheap and easy to administer with broad-spectrum activity against different species of Leishmania. In the Yucatan Peninsula, Mayan traditional healers have used Pentalinon andrieuxii root for the topical treatment of CL for many years, indicating that P. andrieuxii contains antileishmanial molecules that could represent potential new drugs for leishmaniasis. We have found that a hexane extract of P. andrieuxii root (PARE) has potent antileishmanial activity both in vitro and in vivo. PARE kills Leishmania in vitro as efficiently as Glucantime(tm), and is also effective against intracellular parasites. Our preliminary data show that topical treatment with PARE is also effective in limiting L. mexicana infection in mice. Work on our ongoing R21 project (Isolation of novel antileishmanial molecules from Pentalinon andrieuxii Root; AI07639-01A1; A. Satoskar, investigator, A.D. Kinghorn, Co- investigator) has already led to the identification of several compounds with leishmanicidal activity in PARE, including two novel sterols. More bioactive molecules are expected to be isolated from the plant before the completion of this R21 project in August 2010. This application in response to RFA-OD-10-005 is to expand our ongoing studies and to undertake preclinical testing on antileishmanial molecules isolated from the plant P. andrieuxii and from fungi from Mycosynthetix Inc. In Aim 1, we will isolate antileishmanial molecules from the different components of the plant and identify their source(s). Aim 2 will use animal models to evaluate the safety and efficacy of these plant-derived molecules, as well as fungi-derived molecules, in treatment of different forms of leishmaniasis, as well as VL caused by parasites resistant to conventional drugs. Aim 3 will determine the mechanism(s) of action of molecules that are active in our animal studies. Our team is uniquely poised to perform the studies due to the complementary expertise in leishmaniasis (Satoskar), phytochemistry (Kinghorn), synthetic chemistry (Fuchs), and mycology/endophytic fungi (Pearce). Our studies should determine how bioactive molecules in P. andrieuxii mediate antileishmanial activity and provide information on their safety and efficacy to treat infections caused by Leishmania strains that are resistant to conventional treatment. Together these data will lay the foundation for advancing future clinical studies on these molecules for better treatment of various forms of leishmaniasis. PUBLIC HEALTH RELEVANCE: Infections caused by an intracellular protozoan parasite Leishmania are a major global health problem, and emergence of drug-resistant parasites is rapidly increasing world-wide. The overall goal of this project is to discover novel antileishmanial drugs from the plant Pentalinon andreuxii for treating different forms of leishmaniasis.