Identification of molecular target (s) of action of the anthelmintic praziquantel in the human host

项目摘要 寄生虫感染血吸虫病折磨着全世界超过2亿人， 单一药物，吡喹酮（PZQ）。虽然PZQ作为一种有效的临床药物已经有近四十年的历史， PZQ的几个特征不太理想，包括缺乏对分子靶点的了解， 这种药。这种机制信息的缺乏阻碍了替代疗法的合理设计， 面对PZQ无法杀死寄生生命周期的所有阶段，以及寄生虫的出现， 对PZQ暴露表现出不应性的菌株。本项目的长期目标是确定目标 参与PZQ在体内，以促进下一代驱虫药的开发。这项建议是 基于最近的观察，PZQ已被证明与5-羟色胺（5-HT）受体相互作用， 人类宿主这是一个有趣的观察，因为5-HT信号调节血管收缩， 其中成虫血吸虫位于肠系膜脉管系统内。这些宿主血管的相互作用 有助于PZQ作为临床药物的功效，以及这些相互作用是否为寄生虫提供线索 PZQ的目标是未回答的问题。 我的研究生培训计划将首先集中在确定PZQ在人类宿主中的目标。我将测试 假设PZQ在宿主中作为色胺能药效团，与色胺能结合相互作用 特异性5-HT G蛋白偶联受体（R-PZQ）和瞬时受体电位通道（S-PZQ）上的位点。 在确定了PZQ的相关宿主靶点（目标1）后，我可以评估PZQ是否与这些靶点相互作用。 确定的宿主信号传导途径有助于这种药物的治疗效果（目的2）。较长期 这些活性的意义在于揭示PZQ可能的寄生靶标。提出了两个目标。 在目的1中，将使用以下定义宿主肠系膜血管系统中PZQ对映体的宿主靶标： 药理学和遗传学操作结合钢丝肌造影术来测量收缩性 离体肠系膜动脉张力。在目标2中，PZQ与已识别主机交互的重要性 在PZQ与宿主相互作用的条件下， 目标受损。对肠系膜血流量（对将蠕虫冲到肝脏很重要）、蠕虫和虫卵的影响 将检查血吸虫病小鼠模型中的负荷和炎症损伤。本研究是 重要，因为它将揭示这种重要治疗方法所涉及的靶点和途径， 在近40年的临床使用中未得到解决。我的项目的成功完成将有助于PZQ的识别 靶点，从而开发下一代抗肿瘤药物。

PROJECT SUMMARY The parasitic infection schistosomiasis afflicts over 200 million people worldwide and is clinically treated by a single drug, praziquantel (PZQ). Although PZQ has served as an effective clinical agent for almost four decades, several features of PZQ are less than ideal including a lack of understanding about the molecular target(s) of this drug. This lack of mechanistic information impedes rational design of alternative therapeutics and is alarming in the face of an inability of PZQ to kill all stages of the parasitic lifecycle, and the emergence of schistosome strains exhibiting refractoriness to PZQ exposure. The long-term goal of this project is to define the target(s) engaged by PZQ in vivo to facilitate development of the next-generation of anthelmintic drugs. This proposal is based upon recent observations that PZQ has been shown to interact with serotonin (5-HT) receptors in the human host. This is an interesting observation as 5-HT signaling regulates contraction of the blood vessels in which the adult blood flukes reside within the mesenteric vasculature. Whether these host vascular interactions contribute to the efficacy of PZQ as a clinical agent, and whether these interactions provide clues to the parasitic target(s) of PZQ are unanswered questions. My graduate training proposal will first focus on defining targets of PZQ in the human host. I will test the hypothesis that PZQ acts as a tryptaminergic pharmacophore in the host, interacting with tryptaminergic binding sites on specific 5-HT G protein coupled receptors (R-PZQ), and transient receptor potential channels (S-PZQ). Having identified the relevant host targets of PZQ (Aim 1), I can then assess whether PZQ interaction with these defined host signaling pathways contributes to the therapeutic effectiveness of this drug (Aim 2). A longer term significance of these activities will be for revealing likely parasitic target(s) of PZQ. Two Aims are proposed. In Aim 1, host targets of PZQ enantiomers in the host mesenteric vasculature will be defined using pharmacological and genetic manipulations in conjunction with wire myography to measure the contractile tone of isolated mesenteric arteries. In Aim 2, the importance of PZQ interactivity with the identified host receptors will be assessed in schistosome-infected mice under conditions where PZQ interactivity with host targets is impaired. Effects on mesenteric blood flow (important for flushing worms to the liver), worm and egg burden, and inflammatory damage in the mouse model of schistosomiasis will be examined. This research is significant, as it will reveal target(s) and pathways engaged by this important therapeutic that have proved unresolved over almost 40 years of clinical use. Successful completion of my project will aid identification of PZQ target(s) and thereby the development of the next generation of antischistosomal drugs.