RESISTANCE & MODULATION OF LEVAMISOLE RECEPTOR CHANNELS

反抗

• 批准号: 6256352
• 负责人: Richard John Martin
• 金额: $ 21.68万
• 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 2005-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6256352
• 关键词: Nematoda; cGMP dependent protein kinase; drug receptors; drug resistance; enzyme activity; enzyme inhibitors; levamisole; phosphoprotein phosphatase; protein kinase A; protein kinase C; protein structure function; protein tyrosine kinase; voltage /patch clamp

DESCRIPTION (Adapted from the Applicant's Abstract): Ascariasis and hookworm infections are carried by 1.6 billion people throughout the world and in 2 percent of cases cause loss of life. Anthelmintics, including levamisole and related drugs (pyrantel and oxantel), are used to combat nematode parasites, but the development of resistance is a concern. The long-range objective is to improve and protect human health by protecting the efficacy of anthelmintic drugs by controlling and reversing resistance. The objective of the application is to identify mechanisms that regulate the sensitivity of the response of nematode parasite levamisole receptor channels. Our central hypothesis is that competing processes (phosphorylation-dephosphorylation) modulate levamisole responses, and that modification of the processes can produce a decrease or increase in resistance. We developed this hypothesis on the basis of: 1) analysis showing consensus regulatory phosphorylation sites on levamisole receptors; 2) our published and preliminary data showing reduced patency of levamisole receptor channels in resistant nematodes; 3) strong preliminary data that shows levamisole responses are reduced by inhibition of protein kinases. The rationale for the research is that, once mechanisms for regulating levamisole receptor channels are known, pharmacological approaches can be formulated to prevent or overcome resistance, and to maintain the efficacy of levamisole and related anthelmintics. In most experiments we will use electrophysiological techniques on Ascaris suum to examine the properties of the receptor channel. Muscle-flap preparations with current- and voltage-clamp techniques will be used for screening drug effects. We will use muscle-vesicle preparations and patch-clamp technology to measure effects on gating kinetics of levamisole receptor channels of nematode parasites. We will pursue two specific aims to accomplish our current objective: 1) determine mechanisms by which nematode parasites limit their response (P-open) of receptors, and become resistant to levamisole; 2) determine mechanisms that increase P-open values of receptors, in order to reverse resistance to levamisole. We will test our hypothesis that levamisole resistance can be reversed by increased receptor phosphorylation in different species of resistant nematodes. The research is innovative because few groups carry out parasite electrophysiology and others have not developed nematode parasite muscle-vesicle preparations for patch-clamp recordings from levamisole receptor channels. We expect the research to identify mechanisms that decrease levamisole responses (reduce P-open) so parasites become resistant to levamisole and to demonstrate how this resistance can be reversed. The research is significant because application of the results is expected to lead towards methods that will control and overcome resistance to anthelmintics of the levamisole class.

描述（改编自申请人的摘要）：ass虫病和钩虫 感染由全世界16亿人带来 案件的百分比会导致生命损失。驱虫药，包括Levamisole和 相关药物（吡喃和魔药）用于打击线虫寄生虫， 但是，阻力的发展是一个问题。远程目标是 通过保护驱虫的功效来改善和保护人类健康 通过控制和逆转抗性来药物。应用的目的 是确定调节响应敏感性的机制 线虫寄生虫levamiso受体通道。我们的中心假设是 竞争过程（磷酸化 - 脱磷酸化）调节左旋硅唑 响应，过程的修改会产生减少或 阻力增加。我们基于以下基础提出了这一假设 分析表明左旋氨硅硅菌菌的共识调节磷酸化位点 受体； 2）我们已发布和初步数据，显示了降低的通畅性 抗性线虫中的levamisole受体通道； 3）强大的初步数据 这表明通过抑制蛋白激酶来减少左旋硅酶反应。 研究的基本原理是，一旦进行调节的机制 levamisole受体通道是已知的，药理学方法可以是 制定以防止或克服抵抗，并保持 levamisole及相关的驱虫药。在大多数实验中，我们将使用 Accaris suum上的电生理技术检查 受体通道。带有电流和电压钳的肌肉挡板制剂 技术将用于筛选药物效应。我们将使用Muscle-Vesicle 准备和贴片钳技术，以衡量对门控动力学的影响 线虫寄生虫的levamisole受体通道。我们将追求两个 具体目的是实现我们当前的目标：1）确定机制 哪些线虫寄生虫限制了其受体的反应（p-open），并成为 对左旋唑的抗性； 2）确定增加p开放值的机制 受体，以逆转对levamisole的抗性。我们将测试我们的 假设可以通过增加的受体来逆转左旋硅硅硅硅硅烷的耐药性 不同种类的抗性线虫中的磷酸化。研究是 创新的，因为很少有群体进行寄生虫电生理学等 尚未开发出线虫寄生虫肌肉的制剂 来自左旋硅硅硅孔受体通道的贴片钳记录。我们期望 研究以识别减少左右反应的机制（减少 p-open）因此寄生虫对levamisole具有抵抗力，并证明了这一点 电阻可以逆转。这项研究很重要，因为应用 结果有望导致将控制和克服的方法 对Levamisole类的驱虫药的抵抗力。