Antiparasitic metabolites from deep subterranean fungi for the treatment of cryptosporidiosis, an AIDS defining disease

隐孢子虫，一种艾滋病定义病原体，也是导致性病的最常见原因之一 在世界范围内，仍然缺乏任何有效的治疗选择。尽管最近取得了一些进展，但药物太少， 开发管道，以保证先进的临床试验的成功。筛选了由以下物质产生的化合物： 从明尼苏达州北方苏丹铁矿深处分离出的真菌鉴定出一组14种相关的 从截形Oidiodendrontruncatum中分离得到的降二萜内酯，其中8个具有抗隐孢子虫的活性， 三种抗弓形虫，对哺乳动物宿主细胞无细胞毒性。一种天然的， 可合成的衍生物系列，包括具有纳摩尔活性的化合物， 病原体允许详细的结构活性关系（SAR）研究，可以快速建立， 产生进入临床前研究的最佳化合物。我们假设这个新发现的 抗寄生虫支架将产生具有体内活性和药代动力学参数的化合物， 治疗发展我们进一步假设，这些化合物将确定一个新的药物靶点， 顶复门我们建议在两个具体目标中检验这些假设： 目的1：测定衍生物系列的抗寄生虫功效和药代动力学性质。在这 我们将测定活性化合物的EC 50、选择性指数和ADME/PK参数，并使用 这些数据选择化合物用于在隐孢子虫感染的严重免疫功能低下的小鼠中进行测试。 探索性子目标将识别和测试额外的次要结构类似物，以扩展结构活性 关系研究。 目的2：确定最有效的Oidiodendron衍生物的分子靶标。为此，我们建议 利用其中三个衍生物的抗弓形虫活性进行正向遗传学研究 实验以确定化合物的目标。平行地，药物亲和力响应靶标稳定性测定 将用弓形虫和隐孢子虫裂解物进行，以补充从 遗传学方法。在其他apicomplexans的潜在同源物将被确定的生物信息学。 天然产品作为寄生虫病的有效和稳健的治疗剂具有经证实的记录; 我们只需要看看青蒿素和伊维菌素，就能掌握Oidiodendron衍生物的潜力， 开发一种新的抗隐孢子虫治疗剂。一些衍生品的双重活动 所述化合物也可有效对抗AIDS相关弓形虫病的可能性。这些 研究是R21机制的理想选择，因为它们是探索性的，高风险/高回报，可能提供 一个新的治疗药效团和一个新的治疗靶点，用于不可治疗的隐孢子虫病。

Cryptosporidium, an AIDS-defining pathogen and one of the most common causes of diarrheal disease worldwide, still lacks any effective therapeutic options. Despite recent advances, there are too few drugs in the development pipeline to guarantee success in advanced clinical trials. A screen of compounds produced by fungi isolated from deep within the Soudan Iron Mine in northern Minnesota identified a set of 14 related norditerpene lactones from Oidiodendron truncatum, eight of which have activity against Cryptosporidium and three against Toxoplasma, with no cytotoxicity to mammalian host cells. The discovery of a natural, synthesizable derivative series that includes compounds with nanomolar activity against two opportunistic pathogens allows for a detailed structure activity relationship (SAR) study that can be quickly built upon to generate an optimal compound for entry into preclinical studies. We hypothesize that this newly discovered anti-parasitic scaffold will yield a compound with in vivo activity and pharmacokinetic parameters favorable for therapeutic development. We further hypothesize that these compounds will identify a new druggable target in apicomplexans. We propose to test these hypotheses in two specific aims: Aim 1: Determine anti-parasitic efficacy and pharmacokinetic properties of the derivative series. In this aim we will determine EC50s, selectivity indices and ADME/PK parameters of active compounds and use these data to choose compounds for testing in Cryptosporidium-infected severely immunocompromised mice. An exploratory sub-aim will identify and test additional minor structural analogs to expand the structure activity relationship studies. Aim 2: Identify the molecular target of the most potent Oidiodendron derivatives. In this aim we propose to take advantage of the anti-Toxoplasma activity of three of the derivatives to conduct a forward genetics experiment to identify the target of the compounds. In parallel, drug affinity responsive target stability assays will be conducted with Toxoplasma and Cryptosporidium lysates to complement the data obtained from the genetics approach. Potential homologs in other apicomplexans will be identified by bioinformatics. Natural products have a proven track record as effective and robust therapeutics for parasitic diseases; one need look no farther than artemisinin and ivermectin to grasp the potential of the Oidiodendron derivatives for development of a new anti-Cryptosporidium therapeutic. The dual activity of some of the derivatives opens up the possibility that the compound(s) may also be effective against AIDS-associated toxoplasmosis. These studies are ideal for the R21 mechanism as they are exploratory and high-risk/high return, potentially providing a new therapeutic pharmacophore and a new therapeutic target for untreatable cryptosporidiosis.