Slo-1K channels, TRP-2 channels, emodepside and diethylcarbamazine in Filaria

丝虫中的 Slo-1K 通道、TRP-2 通道、艾默德苷和二乙基卡马嗪

• 批准号: 10089614
• 负责人: Richard John Martin
• 金额: $ 46.45万
• 依托单位: IOWA STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-16 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10089614
• 关键词: Adult; Adverse effects; African; Anthelmintics; Arachidonic Acids; Area; Basic Science; Blindness; Brugia; Brugia malayi; Calcium; Combined Modality Therapy; Detection; Development; Diethylcarbamazine; Disease; Disputes; Dopachrome isomerase; Evolution; Exposure to; Eye; Female; Filarial Elephantiases; Homologous Gene; Human; In Situ; In Vitro; Infection; Insecta; Intestinal Volvulus; Ion Channel; Knowledge; Larva; Life Cycle Stages; Loa; Loa loa; Loiasis; Mediating; Messenger RNA; Microfilaria; Molecular; Muscle; Nematoda; Nematode infections; Ocular Onchocerciasis; Onchocerca; Onchocerca volvulus; Onchocerciasis; Oocytes; Parasites; Parasitic nematode; Pathway interactions; Pharmaceutical Preparations; Pharmacology; Pharmacotherapy; Potassium Channel; Prevention; Prophylactic treatment; RNA Splicing; Recovery; Research; Resistance; Risk; Services; Site; Surgical Flaps; Techniques; Testing; Toxic effect; Vaccines; Variant; cell motility; comparative; desensitization; design; differential expression; drug action; filaria; gastrointestinal; human model; innovation; knock-down; male; mortality; neglected tropical diseases; novel therapeutics; patch clamp; phase II trial; programs; response; sex; success

Project Summary Filariases are a group of neglected tropical diseases produced by infection with microfilaria of Clade III parasitic nematodes that are transmitted by biting insects. One example is the lymphatic filariasis produced by Brugia malayi. Lymphatic filariasis is a debilitating and disfiguring disease which occurs in 120 million people worldwide. Other filarial diseases are River Blindness produced by Onchocerca volvulus and loiasis produced by Loa loa. Prevention and treatment of these nematode parasite diseases relies on the use of anthelmintic drugs because no effective vaccines are available. Prophylaxis using Mass Drug Administration [MDA] programs are limited by the efficacy of existing anthelmintics. Diethylcarbamazine is a mainstay for the treatment of lymphatic filariasis and loiasis in most parts of the world, except in areas where onchocerciasis is present because it is contra-indicated by risks of blindness. Diethylcarbamazine produces rapid clearance of microfilaria and causes ~40% mortality of adult parasites (macrofilaricide). A number of studies have suggested that diethylcarbamazine has an indirect host- mediated mode of action and that diethylcarbamazine acts by changing host arachidonic acid pathways. We have observed that diethylcarbamazine has direct effects on filarial nematodes. We present preliminary observations that show that diethylcarbamazine increases the opening of TRP-2 channels in Brugia malayi, and opening of calcium-activated SLO-1 K channels. The effect is a rapid, transient inhibition of motility followed by recovery: the response accommodates. Emodepside is an emerging and important cyclooctadepsipeptide class of anthelmintic that also has effects on microfilaria and adult filaria. Emodepside treatments could allow a major advance over existing mass drug administration (MDA) programs which require regular treatments to kill adult parasites. One of the sites of action of emodepside is on nematode SLO-1 K channels where opening of the channels inhibits motility, but it is not effective against all filaria. Here we propose to compare effects on filarial SLO- 1 K channels from Brugia, Onchocerca and Loa and to examine actions and interactions of these two drugs to explore their mode of action. We have 3 aims: Aim #1: Characterize, in vitro, the concentration motility-inhibition-response relationships of diethylcarbamazine and emodepside and their combination on: A) Brugia microfilaria; B) Brugia adult females; C) Brugia adult males. We will test the hypothesis that effects of diethylcarbamazine and emodepside are additive, synergistic or antagonistic and dependent of life-cycle stage and sex. Aim #2 Characterize the SLO-1 K channel current responses to diethylcarbamazine and emodepside in isolated Brugia malayi muscle flaps under patch-clamp We will test the hypotheses: a) that the effects of emodepside and diethylcarbamazine interact; b) that the interactions of diethylcarbamazine and emodepside are dependent on the presence of TRP-2 by knockdown of TRP-2 channels; and c) that TRP-2 and SLO-1 channel message & channel opening accommodates during prolonged exposure to diethylcarbamazine or emodepside. Aim #3: Characterize the comparative molecular pharmacology of: a) different SLO-1 K channels of Brugia malayi, Onchocerca volvulus and Loa loa and; b) TRP-2 channels of Brugia malayi and Loa loa expressed in oocytes. We will test the hypothesis that the pharmacology and potencies of emodepside and diethylcarbamazine on SLO-1 K channels and TRP-2 channels of, Brugia, Onchocerca and Loa are different and also different to a human channel homologue. We will examine channel desensitization. The proposal is innovative, using a combination of techniques to test the effects of diethylcarbamazine and emodepside on their putative target sites, SLO-1 K channels of filarial. The overall impact of using our mixture of techniques, will be discovery and comparison of effects of diethylcarbamazine and emodepside on different species of filarial TRP-2 channels and SLO-1 K channels. Knowledge of the molecular actions of these drugs is required for: a) molecular detection of sensitivity of different filarial species and resistance; b) designing new drugs and combination therapies; c) predicting and understanding sensitivities of different nematode parasite species; and d) predicting possible host toxicity.

项目概要 丝虫病是一组被忽视的热带疾病，由感染第三支微丝蚴引起 通过叮咬昆虫传播的寄生线虫。淋巴丝虫病就是一个例子 由马来丝虫生产。淋巴丝虫病是一种使人衰弱和毁容的疾病，发生在 全球有 1.2 亿人。其他丝虫病还有由盘尾丝虫引起的河盲症 Loa loa 产生的扭转和罗阿西斯。这些线虫寄生虫病的防治 由于没有有效的疫苗，只能依靠使用驱虫药物。预防使用 大众药物管理局 [MDA] 计划受到现有驱虫药功效的限制。 二乙基卡马嗪是大多数地区治疗淋巴丝虫病和罗阿虫病的主要药物。 世界各地，但存在盘尾丝虫病的地区除外，因为盘尾丝虫病存在失明风险。 二乙基卡马嗪可快速清除微丝蚴并导致约 40% 的成虫死亡率 （杀大丝虫剂）。许多研究表明二乙基卡马嗪具有间接宿主- 介导的作用模式，二乙基氨基甲嗪通过改变宿主花生四烯酸途径发挥作用。 我们观察到二乙基氨基甲嗪对丝虫线虫有直接作用。我们呈现 初步观察表明，二乙基卡马嗪可增加 TRP-2 通道的开放 马来丝虫，以及钙激活 SLO-1 K 通道的开放。效果是快速、短暂的 运动抑制后恢复：反应适应。 Emodepside 是一种新兴且重要的环八缩酚肽类驱虫药，也具有 对微丝蚴和成丝虫的影响。 Emodepside 治疗可能比现有疗法取得重大进步 大规模药物管理 (MDA) 计划，需要定期治疗以杀死成虫寄生虫。一 emodepside 的作用位点在线虫 SLO-1 K 通道上，其中通道开放 抑制蠕动，但并非对所有丝虫有效。在这里，我们建议比较对丝虫 SLO- 的影响 来自丝虫属、盘尾丝虫和 Loa 的 1 K 通道，并检查这两者的作用和相互作用 药物以探索其作用方式。 我们有 3 个目标： 目标#1：在体外表征浓度迁移-抑制-响应关系 二乙基卡马嗪和艾莫德苷以及它们的组合对：A)丝虫丝蚴； B）布鲁吉亚 成年女性； C) 布鲁吉亚成年男性。 我们将检验以下假设：二乙基卡马嗪的作用 和艾默德苷具有相加、协同或拮抗作用，并且依赖于生命周期阶段和性别。 目标 #2 表征 SLO-1 K 通道电流对二乙基氨基甲嗪的响应和 膜片钳下分离的马来丝虫肌瓣中的艾莫德苷 我们将测试假设： a) 艾莫德苷和二乙基卡马嗪的作用是相互作用的； b) 相互作用 二乙基卡马嗪和艾默德苷通过敲低 TRP-2 依赖于 TRP-2 的存在 渠道； c) TRP-2 和 SLO-1 信道消息和信道开放在 长时间接触二乙基卡马嗪或艾默德赛。 目标 #3：表征以下各项的比较分子药理学：a) 不同的 SLO-1 K 通道 马来丝虫、盘尾丝虫和罗阿罗亚； b) 马来丝虫的 TRP-2 通道和 Loa Loa 在卵母细胞中表达。 我们将检验以下假设： 艾莫德苷和二乙基卡马嗪对丝虫属、盘尾丝虫属 SLO-1 K 通道和 TRP-2 通道的影响 和 Loa 不同，也不同于人类通道同源物。我们将检查渠道 脱敏。 该提案具有创新性，使用多种技术组合来测试二乙基卡马嗪的效果 和 emodepside 位于丝虫的假定靶位点 SLO-1 K 通道上。使用的总体影响 我们的技术组合将发现并比较二乙基卡马嗪和 emodepside 对不同物种的丝虫 TRP-2 通道和 SLO-1 K 通道的影响。的知识 这些药物的分子作用需要： a) 分子检测不同丝虫的敏感性 物种和抵抗力； b) 设计新药和联合疗法； c) 预测和 了解不同线虫寄生虫种类的敏感性； d) 预测可能的宿主毒性。