Pharmacological Diversity of nAChRs in Clade III Nematodes: Levamisole receptors

进化枝 III 线虫中 nAChR 的药理学多样性：左旋咪唑受体

• 批准号: 8786864
• 负责人: Richard John Martin
• 金额: $ 35.95万
• 依托单位: IOWA STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8786864
• 关键词: Adult; Affect; Agonist; Animals; Anthelmintics; Ascariasis; Ascaris; Ascaris lumbricoides; Ascaris suum; Biological Assay; Brugia; Brugia malayi; Caenorhabditis elegans; China; Cloning; Complex; Country; Development; Disease; Dose; Drosophila acetylcholine receptor alpha-subunit; Drug Combinations; Drug Controls; Drug effect disorder; Elephantiasis; Figs - dietary; Filarial Elephantiases; Future; Health; Human; Intestines; Investigation; Ion Channel; Knowledge; Lactones; Larva; Lead; Levamisole; Methods; Molecular; Muscle; Muscle Contraction; Nematoda; Nicotinic Receptors; Outcome; Parasites; Parasitic Diseases; Parasitic nematode; Pharmaceutical Preparations; Pharmacology; Preparation; Prevention; Property; Refractory; Research; Research Personnel; Resistance; Resistance development; Site; Surgical Flaps; System; Testing; Therapeutic; Therapeutic Effect; Toxin; Vaccines; Variant; Xenopus oocyte; avermectin; channel blockers; chemotherapy; cholinergic; drug development; filaria; improved; innovation; levamisole resistance; neglected tropical diseases; novel; patch clamp; receptor; response; stoichiometry; synergism; transmission process; voltage clamp; voltage/patch clamp

DESCRIPTION (provided by applicant): 1. The Neglected Tropical Diseases include ascariasis and lymphatic filariasis. These diseases are caused by parasitic nematodes that are grouped in Clade III because of their molecular similarities. Ascariasis is caused by the large intestinal roundworm, Ascaris lumbricoides. Worldwide, it occurs in 1.4 billion people. Lymphatic filariasis (elephantiasis) threatens over a billion people in 83 countries; it is caused by filaria nematodes like Brugia malayi. Control of these nematode parasites (adults or larvae) relies on a limited number of anthelmintic drugs. There are concerns that mass chemotherapy will lead to the development of resistance. There is a significant and urgent need for research that will allow better use of existing drugs, including combinations, to preserve their value, and to develop new drugs. 2. Recently, several novel nematode selective cholinergic anthelmintics, like tribendimidine and derquantel (now synergized with abamectin), have been introduced and increased the significance of cholinergic anthelmintics. Tribendimidine has potential for single-dose Mass Drug Administration. Derquantel has 'resistance busting' actions against worms that are resistant to other cholinergic anthelmintics. The pharmacology of nematode nicotinic receptors (nAChRs) is more complex than has been appreciated. The muscle nAChRs are divided into N-, L- and B-subtypes in the Clade III nematode Ascaris suum. The pharmacology of Clade III muscle receptors (levamisole receptors) are modulated by receptor subunit composition. The therapeutic importance of subtypes and modulation demands further investigation in parasitic nematodes. We have three aims. 3. Our approach will use muscle contraction assays, current-clamp, voltage-clamp, patch- clamp, cloning & Xenopus oocyte expression and pharmacological agents, to characterize actions of cholinergic anthelmintics and the subtypes of their receptors. Aim #1 will characterize the mode of action and subtype selectivity of tribendimidine in A. suum. It will test the hypothesis that tribendimidine is not selective for the L-subtype of nAChR but another type in A. suum and determine if its action as an open-channel blocker limits efficacy. Aim #2 will examine the effects of subunit arrangements and stoichiometry on pharmacology of Ascaris nAChRs. It will express four specific nicotinic receptor subunits from A. suum in different combinations to test the hypothesis that different subunit compositions reproduce the pharmacological diversity of native muscle receptors (levamisole receptors). Aim #3 will characterize nAChR responses and receptors in B. malayi, to test the hypothesis that the subtypes are functionally similar to the Clade III nematode, A. suum. 4. The proposal is innovative, exploring unknown drug effects and effects of subunit arrangements on the pharmacological properties of Clade III nAChRs. We also extend, to the Brugia malayi parasite preparation, the methods that this group of investigators has developed. 5. The overall impact will be a powerful influence on: expansion & informed use of tribendimidine, a potential single-dose MDA; the expansion and informed use of the pharmacological diversity of nicotinic anthelmintic target sites in Clade III nematodes; use of a novel B. malayi preparation for studying ion-channel targets for future drug development; development or informed use of combinations (e.g. derquantel with avermectins; or combinations of subtype selective cholinergic anthelmintics).

描述（申请人提供）： 1. 被忽视的热带病包括蛔虫病和淋巴丝虫病。这些疾病是由寄生线虫引起的，由于其分子相似性，这些线虫被归为进化枝 III。蛔虫病是由大肠蛔虫（蛔虫）引起的。在全世界范围内，有 14 亿人患有此病。淋巴丝虫病（象皮病）威胁着 83 个国家超过 10 亿人；它是由丝虫线虫（如马来丝虫）引起的。对这些线虫寄生虫（成虫或幼虫）的控制依赖于有限数量的驱虫药。有人担心大规模化疗会导致耐药性的产生。迫切需要进行研究，以便更好地利用现有药物（包括组合药物）以保持其价值并开发新药。 2.最近，几种新型线虫选择性胆碱能驱虫药，如三苯脒和德喹泰（现已与阿维菌素协同作用）的推出，增加了胆碱能驱虫药的重要性。 Tribendimidine 具有用于单剂量大规模药物管理的潜力。 Derquantel 对对其他胆碱能驱虫药有抗药性的蠕虫具有“消除耐药性”作用。线虫烟碱受体 (nAChR) 的药理学比人们想象的更为复杂。在 Clade III 线虫蛔虫中，肌肉 nAChR 分为 N 亚型、L 亚型和 B 亚型。 Clade III 肌肉受体（左旋咪唑受体）的药理学受受体亚基组成的调节。亚型和调节的治疗重要性需要对寄生线虫进行进一步研究。我们有三个目标。 3. 我们的方法将使用肌肉收缩测定、电流钳、电压钳、膜片钳、克隆和非洲爪蟾卵母细胞表达和药理制剂，来表征胆碱能驱虫药及其受体亚型的作用。目标#1 将描述三苯脒在 A. suum 中的作用模式和亚型选择性。它将测试三苯脒对 nAChR 的 L 亚型而不是猪曲霉中的另一种类型的 nAChR 没有选择性的假设，并确定其作为开放通道阻滞剂的作用是否会限制功效。目标 #2 将检查亚基排列和化学计量对蛔虫 nAChR 药理学的影响。它将以不同的组合表达来自 A. suum 的四种特定烟碱受体亚基，以测试不同亚基组合再现天然肌肉受体（左旋咪唑受体）的药理学多样性的假设。目标 #3 将描述马来细线虫中 nAChR 反应和受体的特征，以检验这些亚型在功能上与进化枝 III 线虫 A. suum 相似的假设。 4. 该提案具有创新性，探索了未知的药物作用以及亚基排列对Clade III nAChRs药理特性的影响。我们还将这组研究人员开发的方法扩展到马来丝虫寄生虫制剂。 5. 总体影响将对以下方面产生重大影响： 三苯脒（一种潜在的单剂量 MDA）的扩大和知情使用； 扩展和知情使用进化枝 III 线虫中烟碱驱虫药靶位点的药理学多样性；使用新型马来芽孢杆菌制剂研究未来药物开发的离子通道靶点； 开发或知情使用组合（例如德喹泰与阿维菌素；或亚型选择性胆碱能驱虫药的组合）。