Identification of novel anthelmintics through a target-based screen of a parasite ion channel

项目总结 世界上超过三分之一的人口感染了寄生虫。最严重的感染之一 支持被忽视的热带病血吸虫病(血吸虫病)，由寄生扁虫引起 血吸虫属，它困扰着全世界约2亿人。治疗的主流药物疗法 血吸虫病和其他几种寄生虫感染是吡喹酮(PZQ)的药物。然而， PZQ的几个功能受到严重限制。这些问题包括PZQ无法杀死寄生虫的所有阶段 根据PZQ的次优治愈率和现场报告，生命周期、临床对PZQ作为单一疗法的依赖 耐药性，以及无法改进PZQ药效团或机械地定义这一点 毒品起作用了。因此，有必要开发下一代驱虫剂，理想的是对一种 广谱的PZQ敏感的蠕虫寄生虫。 我们的实验室在寄生虫中发现了PZQ的靶标，为我们提供了新的批判性见解[1， 2]。我们最近发现了一种钙离子可通透的瞬时受体电位(Trp)离子通道(Sm.TRPMPZQ)。 曼氏血吸虫复制了PZQ对血吸虫的作用特征：纳摩尔效力， (R)-PZQ的立体选择性，并调节持续的细胞毒性钙离子进入[1，2]。有了这个目标， 现在可以进行筛选活动，以确定该通道的新配体/调节剂 作为下一代驱虫药的潜力。因此，为了在这一突破的基础上，我们组建了一个 团队结合了高吞吐量筛选(HTS)、领导优先级确定和优化(Scripps)方面的专业知识 以及在寄生扁虫生物学方面的内部专业知识(威斯康星医学院，MCW)。 该团队将(I)对Sm.TRPMPZQ(佛罗里达州斯克里普斯)进行主筛选，并(Ii)验证结果 HITS在体外和体内对血吸虫寄生虫的有效性，使用小鼠模型 血吸虫病感染(MCW)。对其他血吸虫物种的优先命中也将进行评估 蠕虫，以及长期内与临床相关的其他寄生扁虫。试点筛选和验证 作为初步数据提供的数据支持目标识别、分析优化和 小型化，以及拟议的HIT验证管道的可行性。 所提议的活动通过支持(I)鉴定新的小分子而与这种FOA相关 具有治疗传染病的潜力和(Ii)对寄生虫Trp离子生物学的新见解 作为新的药物靶点，到目前为止几乎没有受到关注的渠道。如果成功，这些活动将 为下一代抗寄生虫药物的应用提供新的线索。

PROJECT SUMMARY Over a third of the world's population is infected with parasitic worms. One of the most burdensome infections underpins the neglected tropical disease schistosomiasis (Bilharzia) caused by parasitic flatworms of the genus Schistosoma, which afflicts ~200 million people worldwide. The mainstay pharmacotherapy for schistosomiasis, and several other parasitic helminth infections, is the drug praziquantel (PZQ). However, several features of PZQ are severely limiting. These include an inability of PZQ to kill all stages of the parasitic life cycle, clinical reliance on PZQ as a monotherapy in light of sub-optimal cure rates and field reports of PZQ resistance, as well as an inability to improve upon the PZQ pharmacophore or define mechanistically how this drug works. Consequently, there is a need to develop next generation anthelmintics, ideally active against a broad spectrum of PZQ-sensitive helminth parasites. Our laboratory has provided new critical insight by discovering the target of PZQ in parasitic schistosomes [1, 2]. We recently identified a Ca2+-permeable transient receptor potential (TRP) ion channel (Sm.TRPMPZQ) in Schistosoma mansoni that reproduces the characteristics of PZQ action on schistosomes: nanomolar potency, stereoselectivity for (R)-PZQ, and mediation of a sustained, cytotoxic Ca2+ entry [1, 2]. With this target in hand, it is now possible to conduct a screening campaign to identify novel ligands/regulators of this channel with potential as next generation anthelmintics. Therefore, to build upon this breakthrough, we have assembled a team combining expertise in high throughput screening (HTS), lead prioritization and optimization (Scripps Florida), together with in-house expertise in parasitic flatworm biology (Medical College of Wisconsin, MCW). This team will (i) execute a primary screen against Sm.TRPMPZQ (Scripps Florida) and (ii) validate the resulting hits for efficacy against parasitic schistosome worms ex vivo, and in vivo using a murine model of schistosomiasis infection (MCW). Prioritized hits will also be evaluated against other species of schistosome worms, and in the longer term other parasitic flatworms with clinical relevance. A pilot screen and validation data presented as preliminary data support the rigor of target identification, assay optimization and miniaturization, and feasibility of the proposed pipeline for hit validation. The proposed activities have relevance to this FOA by supporting (i) the identification of novel small molecules with potential to treat infectious diseases and (ii) generation of new insight into the biology of parasite TRP ion channels, which have received little attention to date as novel drug targets. If successful, these activities will provide new leads with potential for usage as next generation antiparasitics.