A constitutively active G protein-coupled acetylcholine receptor regulates motility of larval Schistosoma mansoni.
A constitutively active G protein-coupled acetylcholine receptor regulates motility of larval Schistosoma mansoni.
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DOI：
10.1016/j.molbiopara.2015.09.001
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发表时间：
2015-07
影响因子：
1.5
通讯作者：
Ribeiro P
中科院分区：
文献类型：
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作者：
MacDonald K;Kimber MJ;Day TA;Ribeiro P
蠕虫的神经肌肉系统控制着各种基本的生物学过程，因此代表了新药物靶点的良好来源。神经活性物质乙酰胆碱控制曼氏血吸虫的运动，但其作用方式尚不清楚。在这里，我们提出了第一个证据的功能G蛋白偶联乙酰胆碱受体在S。mansoni，我们将其命名为SmGAR。生物信息学分析表明，SmGAR属于无脊椎动物GAR样受体的一个分支，与脊椎动物毒蕈碱乙酰胆碱受体相关。在酵母中的功能表达研究表明，SmGAR是组成型活性，但可以进一步激活乙酰胆碱，并在较小程度上，胆碱能激动剂，卡巴胆碱。抗胆碱能药物，阿托品和异丙嗪，被发现对SmGAR具有反向激动剂活性，导致受体的基础活性显著降低。RNAi表型分析表明，SmGAR活性的抑制在早期阶段的幼虫Escherichiomulae导致幼虫运动的急剧减少。总之，我们的研究结果提供了第一个分子证据，表明胆碱能GAR样受体存在于海马体中，并且是幼虫适当运动控制所必需的。结果进一步确定SmGAR作为抗寄生虫药物靶向的可能候选者。
The neuromuscular system of helminths controls a variety of essential biological processes and therefore represents a good source of novel drug targets. The neuroactive substance, acetylcholine controls movement of Schistosoma mansoni but the mode of action is poorly understood. Here, we present first evidence of a functional G protein-coupled acetylcholine receptor in S. mansoni, which we have named SmGAR. A bioinformatics analysis indicated that SmGAR belongs to a clade of invertebrate GAR-like receptors and is related to vertebrate muscarinic acetylcholine receptors. Functional expression studies in yeast showed that SmGAR is constitutively active but can be further activated by acetylcholine and, to a lesser extent, the cholinergic agonist, carbachol. Anti-cholinergic drugs, atropine and promethazine, were found to have inverse agonist activity towards SmGAR, causing a significant decrease in the receptor’s basal activity. An RNAi phenotypic assay revealed that suppression of SmGAR activity in early-stage larval schistosomulae leads to a drastic reduction in larval motility. In sum, our results provide the first molecular evidence that cholinergic GAR -like receptors are present in schistosomes and are required for proper motor control in the larvae. The results further identify SmGAR as a possible candidate for antiparasitic drug targeting.