Subversion of parasite neuromuscular function is a key strategy for anthelmintic drug development. Schistosome Ca2+ signaling has been an area of particular interest for decades, with a specific focus on L-type voltage-gated Ca2+ channels (Cavs). However, the study of these channels has been technically challenging. One barrier is the lack of pharmacological probes that are active on flatworms, since the dihydropyridine (DHP) based ligands typically used to study Cavs are relatively ineffective on schistosomes. Here, we have characterized the effect of a structurally distinct putative L-type Cav agonist, FPL-64176, on schistosomes cultured ex vivo and in an in vivo murine model of infection. Unlike DHPs, FPL-64176 evokes rapid and sustained contractile paralysis of adult Schistosoma mansoni reminiscent of the anthelmintic praziquantel. This is accompanied by tegument disruption and an arrest of mitotic activity in somatic stem cells and germ line tissues. Interestingly, this strong ex vivo phenotype was temperature dependent, with FPL-64176 treatment being less potent at 37 °C than 23 °C. However, FPL-64176 caused intra-tegument lesions at the basement membrane of worms cultured ex vivo under both conditions, as well as an in vivo hepatic shift of parasites from the mesenteric vasculature of infected mice to the liver. Gene expression profiling of worms harvested following in vivo FPL-64176 exposure reveals differences in transcripts associated with muscle and extracellular matrix function, as well as female reproduction, which is consistent with the worm phenotypes observed following ex vivo drug treatment. These data advance FPL-64176 as a useful tool to study schistosome Ca2+ signaling, and the benzoyl pyrrole core as a hit compound that may be optimized to develop new parasite-selective leads.

中文翻译：

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钙通道激动剂FPL-64176的抗血吸虫作用。

颠覆寄生虫的神经肌肉功能是驱虫药开发的关键策略。数十年来，血吸虫Ca2 +信号一直是一个特别令人关注的领域，特别关注L型电压门控Ca2 +通道（Cavs）。但是，对这些渠道的研究在技术上具有挑战性。一个障碍是缺乏对扁虫具有活性的药理探针，因为通常用于研究Cavs的基于二氢吡啶（DHP）的配体对血吸虫的功效相对较低。在这里，我们已经表征了结构上不同的假定L型Cav激动剂FPL-64176对离体培养的血吸虫和体内鼠感染模型的影响。与DHP不同，FPL-64176引起成年曼氏血吸虫成虫的快速和持续收缩性麻痹，使人联想起驱虫性吡喹酮。这伴随着皮层破裂和体干细胞和种系组织中有丝分裂活性的停止。有趣的是，这种强烈的离体表型是温度依赖性的，FPL-64176处理在37°C时的效力低于23°C。但是，FPL-64176导致在两种情况下离体培养的蠕虫的基膜处都被膜内损伤，以及体内寄生虫从感染小鼠的肠系膜血管向肝脏的体内肝转移。体内FPL-64176暴露后收获的蠕虫的基因表达谱揭示了与肌肉和细胞外基质功能以及雌性生殖相关的转录本差异，这与离体药物治疗后观察到的蠕虫表型一致。