RESISTANCE & MODULATION OF LEVAMISOLE RECEPTOR CHANNELS

反抗

• 批准号: 6626381
• 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/6626381
• 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）：蛔虫和钩虫 全世界有16亿人感染， %的病例造成生命损失。驱虫药，包括左旋咪唑和 相关药物（噻嘧啶和oxantel），用于对抗线虫寄生虫， 但耐药性的发展是一个问题。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 药物通过控制和逆转耐药性。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。我们的核心假设是， 竞争过程（磷酸化-去磷酸化）调节左旋咪唑 反应，并且修改过程可以减少或 增加阻力。我们提出这一假设的基础是：1） 显示左旋咪唑上共有调节磷酸化位点的分析 受体; 2）我们发表的和初步的数据显示， 抗性线虫中的左旋咪唑受体通道; 3）强有力的初步数据 这表明左旋咪唑的反应被蛋白激酶的抑制所降低。 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 配制以预防或克服耐药性，并维持 左旋咪唑和相关的驱虫剂。在我们将使用的大多数实验中 电生理技术检测猪蛔虫的特性 受体通道。电流钳和电压钳肌瓣制备 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 左旋咪唑受体通道。我们将追捕两名 实现我们当前目标的具体目标：1）确定机制， 这种线虫寄生虫限制了它们对受体的反应（P-开放）， 抗左旋咪唑; 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 左旋咪唑耐药性可通过受体增加而逆转假说 在不同种类的抗性线虫中的磷酸化。这项研究是 创新，因为很少有小组进行寄生虫电生理学和其他 还没有开发出线虫寄生虫肌肉囊泡制剂， 左旋咪唑受体通道的膜片钳记录。我们预计 研究确定降低左旋咪唑反应的机制（减少 P-open），因此寄生虫对左旋咪唑产生耐药性，并证明这是如何 阻力可以逆转。该研究具有重要意义， 这些结果有望导致控制和克服 对左旋咪唑类驱虫药的抗性。