Cholinergic anthelmintics: Tachyphylaxis mechanisms and control in a parasitic nematode model,Brugia malayi

项目摘要 土壤传播的蠕虫感染是全球关注的公共卫生问题，影响超过10亿人 世界各地的人们。蛔虫、鞭虫（鞭虫）和 钩虫（钩虫）影响人们在温暖和潮湿的气候往往缺乏， 卫生和环境卫生，并在温暖的月份在温带地区。受感染的儿童 严重营养不良，并表现出严重的身体和认知发育。控制这些寄生虫 依赖于驱虫药如苯并咪唑类如阿苯达唑的给药， 大环内酯、伊维菌素和烟碱激动剂如左旋咪唑和噻嘧啶。的 对这些驱虫剂的抗性的发展对控制 这些疾病的传播。寄生线虫是一种复杂的生物， 抵抗接触驱虫药的机制。我们已经确定快速耐受是一种 寄生虫利用这种机制来抵抗和恢复运动，继续暴露于 胆碱能驱虫药左旋咪唑。内质网滞留蛋白NRA-2是一种 的蛋白质参与调节快速耐受的女性马来丝虫寄生虫。的 转录因子β 1 -12在速殖蠕虫中上调，并可能在 介导快速耐受。大环内酯，阿维菌素，对自身的影响有限， 成体B的运动性。但是，当与左旋咪唑组合使用时， 快速耐受和运动恢复。在这里，我们建议， 目的#1：检验α-12介导B快速耐受的假设。马来语。我们将 在成年B中敲低daf-12。malayi，以确定其在介导快速耐受中的作用。我们将 测量DAF-12敲低蠕虫中NRA-2的转录水平， 调节nra-2的表达。我们还将使用激动剂靶向α-12， 快速耐受 目的#2：为了检验肌肉钙浓度和钙释放的假设， 左旋咪唑产生的机制在大环化合物的存在下发生了变化， 内酯。我们将研究大环内酯，阿维菌素，伊维菌素， 莫昔克丁延长左旋咪唑所致的麻痹。我们将评估 通过对兰尼碱进行RNAi研究大环内酯引起的钙释放机制 B组有IP 3受体unc-68和itr-1。malayi，并使用 C.优雅 在这些实验的最后，我们将把α-12作为一种新的驱虫靶标 可以帮助预防胆碱能快速耐受。我们就能深入了解 大环内酯对线虫肌肉左旋咪唑钙释放机制的影响这些 研究将为胆碱能快速耐受提供更好的机制见解， 防止蠕虫恢复和抵抗的途径。

Project Summary Soil-transmitted helminth infections are a global concern for public health and affect over 1 billion people worldwide. Infections caused by Ascaris lumbricoides, Trichuris trichiura (whipworms), and Ancylostoma duodenale (hookworms) affect people in warm and moist climates often lacking in hygiene and sanitation and in temperate zones during warmer months. Infected children develop severe malnutrition and show severe physical and cognitive growth. Control of these parasites depends on the administration of anthelmintic drugs like benzimidazoles like albendazole, macrocyclic lactone, ivermectin, and nicotinic agonists like levamisole and pyrantel. The development of resistance to these anthelmintics poses a great challenge in controlling the transmission of these diseases. Parasitic nematodes are complex organisms that adopt complex mechanisms to resist exposure to anthelmintic drugs. We have identified tachyphylaxis as one mechanism the parasite utilizes to resist and recover motility in the continued exposure to the cholinergic anthelmintic levamisole. The endoplasmic reticulum retention protein, NRA-2, is one of the proteins implicated in modulating tachyphylaxis in the female Brugia malayi parasites. The transcription factor, DAF-12 is upregulated in tachyphylactic worms and could play a key role in mediating tachyphylaxis. Macrocyclic lactone, abamectin, has limited effect on its own on the motility of adult B. malayi but, when applied in combination with levamisole, prevents tachyphylaxis and recovery of motility. Here, we propose, Aim #1: To test the hypothesis that DAF-12 mediates tachyphylaxis in B. malayi. We will knockdown daf-12 in adult B. malayi to determine its role in mediating tachyphylaxis. We will measure transcript levels of nra-2 in daf-12 knockdown worms to determine the role of DAF-12 in regulating the expression of nra-2. We will also target DAF-12 using agonists to prevent tachyphylaxis. Aim #2: To test the hypothesis that muscle calcium concentrations & calcium release mechanisms produced by levamisole are changed in the presence of macrocyclic lactones. We will investigate the effects of macrocyclic lactones, abamectin, ivermectin, and moxidectin in prolonging the paralysis induced by levamisole. We will evaluate the change in calcium release mechanisms due to macrocyclic lactones by performing RNAi of the ryanodine and the IP3 receptors, unc-68 and itr-1 in B. malayi, and performing in vivo calcium imaging using C. elegans. At the end of these experiments, we will have characterized DAF-12 as a novel anthelmintic target that could help prevent cholinergic tachyphylaxis. We would have an insight into the effect of macrocyclic lactones on levamisole calcium release mechanisms in nematode muscle. These studies will provide an improved mechanistic insight into cholinergic tachyphylaxis and a rational avenue to prevent worm recovery and resistance.