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，即全球健康和将基础科学发现转化为新的更好的治疗方法。利什曼原虫是一种专性细胞内寄生虫，由沙蝇媒介传播，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1 200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，并被世卫组织列为被忽视的热带病。最近，这种疾病越来越多地出现在美国的犬群中，以及在伊拉克和阿富汗等利什曼原虫流行国家服役的军队人员中。锑类药物（葡聚糖酶（葡聚糖）和戊氧胺（葡聚糖））、两性霉素B和米地辛用于治疗利什曼病。不幸的是，这些药物是有毒的，而且患者的依从性很差，因为其中许多药物需要3-5周的全身给药，而且耐药菌株的出现在世界范围内正在迅速增加。因此，迫切需要一种安全、廉价、易于施用、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Pentalinon和ririeuxii根局部治疗CL，这表明P. andrieuxii含有抗利什曼分子，可能代表潜在的利什曼病新药。我们发现一种正己烷提取物（PARE）在体内和体外都有很强的抗利什曼原虫活性。PARE在体外杀灭利什曼原虫和葡聚糖酶（tm）一样有效，并且对细胞内寄生虫也有效。我们的初步数据表明，局部使用PARE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（从Pentalinon andrieuxii Root中分离出新的抗利什曼原虫分子；AI07639-01A1； A. Satoskar，研究员，ad . Kinghorn，共同研究员）已经在PARE中鉴定出几种具有利什曼原虫活性的化合物，包括两种新的甾醇。在2010年8月完成R21项目之前，预计将从该植物中分离出更多的生物活性分子。RFA-OD-10-005的申请是为了扩大我们正在进行的研究，并对从植物安德列疟原虫和Mycosynthetix Inc.的真菌中分离的抗利什曼原虫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抗利什曼原虫分子并确定其来源。Aim 2将使用动物模型来评估这些植物源性分子以及真菌源性分子在治疗不同形式的利什曼病以及由对常规药物具有耐药性的寄生虫引起的VL方面的安全性和有效性。目的3将确定在我们的动物研究中活跃的分子的作用机制。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，我们的团队在开展研究方面处于独特的地位。我们的研究应该确定安德列蚊的生物活性分子如何介导抗利什曼原虫活性，并提供有关其治疗对常规治疗有耐药性的利什曼原虫菌株引起的感染的安全性和有效性的信息。这些数据将共同为推进这些分子的未来临床研究奠定基础，以更好地治疗各种形式的利什曼病。

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.