Optimizing the Clinical Efficacy of Opioids by TLR4 Blockade

描述（由申请人提供）：阿片诱导的胶质细胞激活，影响疼痛治疗并促进药物成瘾和滥用的发展，是通过toll样受体-4 （TLR4）下游的信号通路调节的，TLR4是一种膜跨越受体，与其辅助蛋白MD-2复合物起作用。由于目前的阿片类药物治疗未能在控制疼痛的同时避免不良后果，因此迫切需要通过TLR4来了解阿片类药物的失调。目前研究的核心假设是，破坏TLR-4/MD-2复合物的形成可以抑制阿片诱导的胶质细胞激活，从而增强镇痛作用，减少阿片耐受性和依赖性。所提出的研究的基本原理是，所鉴定的抑制剂选择性地阻断TLR4和MD-2之间的关键蛋白-蛋白相互作用，将为研究TLR4介导的信号通路在胶质细胞激活中的作用提供有用的工具。拟议的研究是创新的，因为它是第一个药物发现方法，试图调节阿片类药物诱导的胶质细胞激活。建议的高风险/高回报方法，如果成功，预计将产生重大的新结果。首先，这些结果将阐明临床相关阿片诱导的胶质细胞激活的机制。其次，如果成功的话，本研究中发现的TLR4/MD-2相互作用的肽和拟肽拮抗剂可以作为更多类似药物的小分子抑制剂的原型。这些抑制剂可能最终应用于开发新的治疗药物，以提高阿片类镇痛药的临床疗效，治疗阿片类药物成瘾和滥用，以及其他临床相关适应症。拟议的研究建立在一个强大的专业合作团队的基础上，该团队将优化其机会，有效地连接TLR4/MD-2相互作用的原子细节及其宏观效应，即疼痛管理和避免阿片类药物使用的负面后果。在Aim 1中，将使用尖端的计算技术开发阻断TLR4/MD-2复合物形成的TLR4或MD-2拮抗剂。这里的工作假设是，来自结合区域的构象张力肽可以与全长蛋白竞争，从而抑制TLR4/MD-2相互作用。这些肽可以作为计算设计更强抑制剂的起点。在Aim 2中，将测试第二个工作假设，即TLR4/MD-2相互作用的抑制剂可以非竞争性地阻止阿片类药物诱导TLR4介导的胶质细胞激活。细胞分析和动物模型将用于评估TLR4拮抗剂在体外和体内对胶质细胞活化的抑制作用。该研究具有重要意义，因为它有望建立TLR4/MD-2蛋白-蛋白复合物作为优化阿片类镇痛同时预防和治疗阿片类药物滥用的新治疗靶点。就其对科学进步的积极影响而言，这项工作将(1)提高对药物依赖和疼痛抑制的科学理解，(2)允许新一代治疗方法的发展。公共卫生相关性：拟议的研究旨在揭示阿片类药物诱导的神经胶质激活机制，该机制既阻碍了阿片类药物有效控制疼痛的能力，也重要地促进了药物成瘾和滥用的发展。最先进的技术将用于定义、设计、创建和测试新的化学实体，以防止阿片类药物诱导的神经胶质激活，从而优化阿片类药物镇痛，同时防止临床使用阿片类药物的负面后果。

DESCRIPTION (provided by applicant): Opioid-induced glial activation, which compromises pain treatment and contributes to the development of drug addiction and abuse, is regulated via a signaling pathway downstream of toll-like receptor-4 (TLR4), a membrane spanning receptor that functions in complex with its accessory protein MD-2. As current opioid pharmacotherapeutics have failed to control pain while avoiding the negative consequences, there is an urgent need to understand opioid dysregulation via TLR4. The central hypothesis of the current proposal is that disruption of the TLR-4/MD-2 complex formation can inhibit opioid-induced glial activation, thereby enhancing analgesia and reducing opioid tolerance and dependence. The rationale underlying the proposed research is that the identified inhibitors, which selectively block the critical protein-protein interactions between TLR4 and MD-2, will provide a useful tool for investigating the role of the TLR4-mediated signaling pathway in glial activation. The proposed research is innovative because it is the first drug discovery approach attempting to regulate opioid-induced glial activation. The proposed high risk/high reward approach, if successful, is projected to yield significant novel outcomes. First, the results will shed light on the mechanism of the clinically relevant opioid-induced glial activation. Second, if successful, the peptide and peptidomimetic antagonists of the TLR4/MD-2 interactions identified in the proposed research can serve as prototypes for more drug-like small-molecule inhibitors. These inhibitors may eventually find application in the development of novel therapeutics to enhance the clinical efficacy of opioid analgesics and to treat opioid addiction and abuse, as well as other clinically relevant indications. The proposed studies are built on a strong collaborative team with expertise that optimizes its chance to effectively bridge between atomic detail of the TLR4/MD-2 interaction and its macroscopic effect, namely pain management and avoiding negative consequences of opoid use. In Aim 1, antagonists of TLR4 or MD-2 that block the TLR4/MD-2 complex formation will be developed using a cutting-edge computational technology. The working hypothesis here is that conformationally strained peptides derived from the binding region can compete with the full-length protein and thereby inhibit the TLR4/MD-2 interaction. These peptides can serve as starting points for the computational design of stronger inhibitors. In Aim 2, the second working hypothesis, that the inhibitors of the TLR4/MD-2 interactions can non-competitively prevent opioids from inducing TLR4-mediated glial activation, will be tested. Cellular assays and animal models will be used to evaluate the inhibition of glial activation by the TLR4 antagonists both in vitro and in vivo. The proposed research is significant because it is expected to establish the TLR4/MD-2 protein-protein complex as a novel therapeutic target for optimizing opioid analgesia while preventing and treating opioid abuse. Regarding its positive impact on scientific advancements, this work will (1) improve scientific understanding of drug dependence and pain suppression and (2) allow the development of a new generation of therapeutics. PUBLIC HEALTH RELEVANCE: The proposed research aims to unravel the mechanism of opioid-induced glial activation that both hinders the ability of opioids to effectively control pain and also importantly contributes to the development of drug addiction and abuse. State-of-the-art technologies will be employed to define, design, create, and test new chemical entities predicted to prevent opioid induced glial activation, thereby optimizing opioid analgesia while preventing negative consequences of clinical opioid use.