RESISTANCE & MODULATION OF LEVAMISOLE RECEPTOR CHANNELS

反抗

• 批准号: 6840803
• 负责人: Richard John Martin
• 金额: $ 18.06万
• 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 2006-01-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6840803
• 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）：蛔虫病和钩虫 全世界有 16 亿人携带这种病毒，其中 2 % 的病例导致死亡。驱虫药，包括左旋咪唑和 相关药物（pyrantel 和 oxantel）用于对抗线虫寄生虫， 但耐药性的发展令人担忧。长期目标是 通过保护驱虫药的功效来改善和保护人类健康 通过控制和逆转耐药性来治疗药物。申请的目的 是确定调节反应敏感性的机制 线虫寄生虫左旋咪唑受体通道。我们的中心假设是 竞争过程（磷酸化-去磷酸化）调节左旋咪唑 反应，并且过程的修改可以产生减少或 抵抗力增加。我们提出这一假设的基础是：1) 分析显示左旋咪唑上共有的调节磷酸化位点 受体； 2) 我们公布的初步数据显示，患者的通畅率有所下降 抗性线虫中的左旋咪唑受体通道； 3）强有力的初步数据 这表明左旋咪唑反应因抑制蛋白激酶而降低。 这项研究的基本原理是，一旦调节机制 左旋咪唑受体通道是已知的，药理学方法可以是 配制用于预防或克服耐药性，并保持功效 左旋咪唑和相关驱虫药。在大多数实验中我们会使用 猪蛔虫的电生理技术可检查其特性 受体通道。使用电流钳和电压钳制备肌瓣 技术将用于筛选药物效果。我们将使用肌肉囊泡 用于测量对门控动力学影响的制剂和膜片钳技术 线虫寄生虫的左旋咪唑受体通道。我们将追求两个 实现我们当前目标的具体目标：1）确定机制 哪些线虫寄生虫限制了受体的反应（P-开放），并成为 对左旋咪唑耐药； 2) 确定增加 P-open 值的机制 受体，以逆转对左旋咪唑的耐药性。我们将测试我们的 左旋咪唑耐药性可以通过增加受体来逆转的假设 不同种类的抗性线虫中的磷酸化。该研究是 创新是因为很少有团体进行寄生虫电生理学研究 尚未开发出线虫寄生虫肌囊泡制剂 来自左旋咪唑受体通道的膜片钳记录。我们期望 研究以确定减少左旋咪唑反应的机制（减少 P-open）使寄生虫对左旋咪唑产生抗药性并证明这是如何 阻力可以逆转。该研究意义重大，因为应用 研究结果预计将导致控制和克服的方法 对左旋咪唑类驱虫药的耐药性。