Chemogenomic approach to identifying nematode chemoreceptor drug targets in the entomopathogenic nematode Heterorhabditis bacteriophora.

Parasitic nematodes constitute one of the major threats to human health, causing diseases of major socioeconomic importance worldwide. Recent estimates indicate that more than 1 billion people are infected with parasitic nematodes around the world. Current measures to combat parasitic nematode infections include anthelmintic drugs. However, heavy exposure to anthelmintics has selected populations of livestock parasitic nematodes that are no longer susceptible to the drugs, rendering several anthelmintics useless for parasitic nematode control in many areas of the world. The rapidity with which anthelmintic resistance developed in response to these drugs suggests that increasing the selective pressure on human parasitic nematodes will also rapidly generate resistant worm populations. Therefore, development of new anthelmintics is of major importance before resistance becomes widespread in human parasitic nematode populations. G-Protein Coupled Receptors (GPCRs) represent an important target for many pharmacological interventions due to their ubiquitous expression in various cell types. GPCRs contribute to numerous physiological processes, and their ligand binding sites located on cell surfaces make them accessible targets and attractive substrates in terms of druggability. In fact, ~35% of Food and Drug Administration (FDA) and European Medicines Agency (EMA) approved drugs target GPCRs and their associated proteins, with over 300 additional drugs targeting GPCRs at the clinical trial stage. Nematode Chemosensory GPCRs (NemChRs) are unique to nematodes, and therefore represent ideal substrates for target-based drug discovery. Here we set out to identify NemChRs that are transcriptionally active inside the host, and to use these NemChRs in a reverse pharmacological screen to impede parasitic development. Our data identified several NemChRs, and we focused on one that was expressed in neuronal cells and exhibited the highest fold change in transcription after host activation. Next, we performed homology modelling and molecular dynamics simulations of this NemChR in order to conduct a virtual screening campaign to identify candidate drug targets which were ranked and selected for experimental testing in bioassays. Taken together, our results identify and characterize a candidate NemChR drug target, and provide a chemogenomic pipeline for identifying nematicide substrates.

寄生线虫是对人类健康的主要威胁之一，在世界范围内引发具有重大社会经济影响的疾病。近期的估计表明，全球有超过10亿人感染寄生线虫。目前防治寄生线虫感染的措施包括使用驱虫药。然而，大量使用驱虫药导致家畜寄生线虫种群产生抗药性，不再对药物敏感，使得一些驱虫药在世界许多地区对寄生线虫的控制失去作用。针对这些药物产生抗药性的速度之快表明，对人类寄生线虫增加选择压力也将迅速产生抗药虫群。因此，在抗药性在人类寄生线虫种群中广泛传播之前，研发新的驱虫药至关重要。G - 蛋白偶联受体（GPCRs）由于在各种细胞类型中普遍表达，是许多药物干预的重要靶点。GPCRs参与众多生理过程，其位于细胞表面的配体结合位点使其成为可及的靶点，在成药性方面是有吸引力的底物。事实上，约35%的美国食品药品监督管理局（FDA）和欧洲药品管理局（EMA）批准的药物以GPCRs及其相关蛋白为靶点，还有300多种药物在临床试验阶段以GPCRs为靶点。线虫化学感应GPCRs（NemChRs）是线虫所特有的，因此是基于靶点的药物研发的理想底物。在此，我们着手鉴定在宿主体内有转录活性的NemChRs，并在反向药理学筛选中使用这些NemChRs来阻碍寄生虫的发育。我们的数据鉴定出了几种NemChRs，我们重点关注一种在神经元细胞中表达且在宿主激活后转录倍数变化最高的NemChRs。接下来，我们对这种NemChR进行同源建模和分子动力学模拟，以便开展虚拟筛选活动，确定候选药物靶点，对这些靶点进行排序并选择用于生物测定中的实验测试。总之，我们的研究结果鉴定并描述了一个候选的NemChR药物靶点，并提供了一个用于鉴定杀线虫底物的化学基因组学流程。