The Cyclooctadepsipeptide Anthelmintic Emodepside Differentially Modulates Nematode, Insect and Human Calcium-Activated Potassium (SLO) Channel Alpha Subunits.
The Cyclooctadepsipeptide Anthelmintic Emodepside Differentially Modulates Nematode, Insect and Human Calcium-Activated Potassium (SLO) Channel Alpha Subunits.
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DOI：
10.1371/journal.pntd.0004062
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发表时间：
2015
影响因子：
3.8
通讯作者：
Holden-Dye L
中科院分区：
文献类型：
--
作者：
Crisford A;Ebbinghaus-Kintscher U;Schoenhense E;Harder A;Raming K;O'Kelly I;Ndukwe K;O'Connor V;Walker RJ;Holden-Dye L
驱虫药艾莫德苷通过一种与之前驱虫药不同的作用方式麻痹成虫丝虫，最近作为盘尾丝虫病的新治疗方法引起了人们的兴趣。整个生物体数据表明，其驱虫作用是通过选择性激活进化上保守的 Ca2+ 激活 K+ 通道 SLO-1 的线虫亚型来实现的。为了在分子水平上测试这一点，我们使用全细胞电压钳比较了艾莫德苷对来自线虫（秀丽隐杆线虫）、果蝇和人类的异源表达的SLO-1 α亚基直系同源物的作用。有趣的是，我们发现艾默德苷调节线虫（Ce slo-1）、昆虫（果蝇、Dm slo）和人类（hum kcnma1）SLO通道，但调节特征存在离散差异，这与其驱虫功效一致。线虫 SLO-1 电流需要 100 μM 细胞内 Ca2+，并受到 emodepside 的强烈促进（100 nM；+73.0 ± 17.4%；n = 9；p<0.001）。另一方面，果蝇 Slo 电流在 52 nM Ca2+ 存在下被 emodepside (10 μM) 激活，但在 290 nM Ca2+ 存在下被抑制，并表现出特征性整流损失。人类 Slo 需要 300nM Ca2+ 和 emodepside 瞬时促进电流（100nM；+33.5 ± 9%；n = 8；p<0.05），然后持续抑制（-52.6 ± 9.8%；n = 8；p<0.001）。这是艾莫德苷对线虫、昆虫和人类通道作用的首次跨门比较，为该化合物对 SLO 通道的复杂调节提供了新的机制见解。与对秀丽隐杆线虫的整个生物体行为研究一致，这表明其驱虫作用源自 SLO 电流的强烈激活，而在人体通道中未观察到。这些数据为更广泛地应用艾默德赛作为驱虫治疗方法提供了重要基准。丝虫病影响了大约 2 亿人，被忽视疾病药物倡议 (DNDi) 已将开发杀丝虫药物作为优先事项。目前用于伴侣动物的艾莫德赛可以麻痹成虫丝虫，并可能解决人类医学这一未满足的需求。其受体是进化保守的Ca2+激活K+通道，SLO-1。在本文中，我们在线虫中与人类直系同源物 KCNMA1 相比，在理解 emodepside 与其靶受体 SLO-1 的相互作用方面解决了一个重要的知识差距，并在线虫、昆虫和人类中首次对 emodepside 与 slo 通道的相互作用进行跨门分析。有趣的是，这表明 emodepside 调节所有三种生物体异源表达通道的 slo/BK 电流，但调节特征存在离散差异；只有线虫通道表现出艾莫德赛的持续促进作用。这与 emodepside 对线虫行为的影响一致，并表明 emodepside 对线虫通道的这种差异作用可能是其有效的驱虫作用的基础。这些数据为更广泛地应用艾默德赛作为驱虫治疗方法提供了重要基准。
The anthelmintic emodepside paralyses adult filarial worms, via a mode of action distinct from previous anthelmintics and has recently garnered interest as a new treatment for onchocerciasis. Whole organism data suggest its anthelmintic action is underpinned by a selective activation of the nematode isoform of an evolutionary conserved Ca2+-activated K+ channel, SLO-1. To test this at the molecular level we compared the actions of emodepside at heterologously expressed SLO-1 alpha subunit orthologues from nematode (Caenorhabditis elegans), Drosophila melanogaster and human using whole cell voltage clamp. Intriguingly we found that emodepside modulated nematode (Ce slo-1), insect (Drosophila, Dm slo) and human (hum kcnma1)SLO channels but that there are discrete differences in the features of the modulation that are consistent with its anthelmintic efficacy. Nematode SLO-1 currents required 100 μM intracellular Ca2+ and were strongly facilitated by emodepside (100 nM; +73.0 ± 17.4%; n = 9; p<0.001). Drosophila Slo currents on the other hand were activated by emodepside (10 μM) in the presence of 52 nM Ca2+ but were inhibited in the presence of 290 nM Ca2+ and exhibited a characteristic loss of rectification. Human Slo required 300nM Ca2+ and emodepside transiently facilitated currents (100nM; +33.5 ± 9%; n = 8; p<0.05) followed by a sustained inhibition (-52.6 ± 9.8%; n = 8; p<0.001). This first cross phyla comparison of the actions of emodepside at nematode, insect and human channels provides new mechanistic insight into the compound’s complex modulation of SLO channels. Consistent with whole organism behavioural studies on C. elegans, it indicates its anthelmintic action derives from a strong activation of SLO current, not observed in the human channel. These data provide an important benchmark for the wider deployment of emodepside as an anthelmintic treatment. Filarial diseases affect an estimated 200 million people and the Drugs for Neglected Diseases initiative (DNDi) has identified development of macrofilaricidal drugs as a priority. Emodepside, currently used in companion animals, paralyses adult filarial worms and may address this unmet need for human medicine. Its receptor is an evolutionary conserved Ca2+-activated K+ channel, SLO-1. In this paper we address an important knowledge gap in terms of understanding the interaction of emodepside with its target receptor SLO-1 in nematodes in comparison to the human orthologue KCNMA1 and provide the first cross phyla analysis of the interaction of emodepside with slo channels, in nematode, insect and human. Intriguingly, this shows that emodepside modulates slo/BK currents from heterologously expressed channels from all three organisms, however there are discrete differences in the feature of modulation; only the nematode channel exhibits a sustained facilitation by emodepside. This is consistent with the effects of emodepside on C. elegans behaviour and indicates that this differential action of emodepside on the nematode channel likely underlies its potent anthelmintic effects. These data provide an important benchmark for the wider deployment of emodepside as an anthelmintic treatment.