Regulator of G protein signaling proteins differentially control opioid analgesia

G 蛋白信号蛋白的调节剂差异控制阿片类镇痛

• 批准号: 8830955
• 负责人: John R. Traynor
• 金额: $ 52.7万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-04-15 至 2019-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8830955
• 关键词: Absence of pain sensation; Address; Adenylate Cyclase; Affect; Agonist; Analgesics; Area; Behavior; Biological Assay; Calcium; Cells; Clinical; Complex; Coupling; Data; Drug Targeting; Equilibrium; Excision; Family; G Protein-Coupled Receptor Signaling; G-Protein-Coupled Receptors; GTP Binding; GTP-Binding Protein Regulators; GTP-Binding Proteins; Guanosine Triphosphate Phosphohydrolases; Health; Human; Hydrolysis; Hyperalgesia; In Vitro; Injection of therapeutic agent; Knock-in Mouse; Knock-out; Knowledge; Lead; Location; Mediating; Methadone; Methionine Enkephalin; Mission; Mitogen-Activated Protein Kinases; Modality; Modeling; Morphine; Mus; National Institute of Drug Abuse; Neurons; Neurotransmitters; Opioid; Opioid Receptor; Pain; Pain management; Paper; Pathway interactions; Proteins; RGS Proteins; Receptor Signaling; Regulation; Research; Role; Series; Signal Pathway; Signal Transduction; Site; Spinal Cord; System; Tail; Testing; Transgenic Organisms; Translating; Variant; Wild Type Mouse; Withdrawal; Work; addiction; allodynia; base; design; gamma-Aminobutyric Acid; human RGS1 protein; human RGS2 protein; midbrain central gray substance; mu opioid receptors; nociceptin; nociceptin receptor; novel; postsynaptic; receptor; research study; response; tool

DESCRIPTION (provided by applicant): Regulators of G protein Signaling (RGS) proteins are a family of G protein-coupled receptor (GPCR) accessory proteins that are essential for the temporal and spatial control of cell signaling, including signaling downstream of the mu-opioid receptor (MOR). RGS proteins are GTPase accelerating proteins (GAPs) that accelerate the hydrolysis of Galpha bound GTP and promote the formation of inactive Galpha GDP to switch off signaling by GPCRs. We have shown that RGS proteins serve to terminate signaling of MOR to adenylate cyclase and the MAP kinase pathway. On the other hand, efficient signaling of MOR to release intracellular calcium requires RGS protein GAP activity. Thus, RGS activity controls the balance of signaling pathways within a single cell. We recently used a novel tool to explore regulation of GPCR signaling by RGS proteins: a transgenic knock-in mouse that expresses Galpha proteins that are insensitive to the GAP activity of RGS proteins. In these mice antinociception is dependent on the opioid agonist and pain assay employed. For example, in the hot-plate assay loss of RGS regulation potentiates morphine, without affecting methadone, antinociception. In contrast, in the tail-withdrawal assay removal of RGS activity decreases both morphine and methadone antinociception. This suggests the different neuronal pathways involved in these two behaviors show differential sensitivity to RGS protein action. We propose to continue our exploration of these mice to tackle a series of fundamental questions concerning MOR signaling and its relationship to antinociception. For example: Are the differences between antinociceptive tests due to site-specific variation in RGS action? What is the basis of the observed agonist differences? Can the differences be explained by effects at the level of cell signaling? What is the role of other neurotransmitter systems that also use Galpha proteins? Are more clinically-related pain models also regulated by RGS proteins? Our overall conceptual framework is as follows: 1) RGS activity controls the balance of GPCR signaling to multiple pathways and this balance may be disrupted in pain and 2) RGS-induced changes in MOR-mediated-antinociception may reflect an alteration in the balance between neurotransmitter systems, particularly the nociceptin (NOP) system. The proposed studies will advance our understanding of opioid signaling pathways and their regulation by RGS proteins and explain these actions in the context of altered behaviors. Results from this study may be exploited to develop better analgesic drugs.

描述（由申请人提供）：G 蛋白信号传导 (RGS) 蛋白的调节剂是 G 蛋白偶联受体 (GPCR) 辅助蛋白家族，其对于细胞信号传导的时间和空间控制至关重要，包括 mu-下游的信号传导阿片受体（MOR）。 RGS 蛋白是 GTP 酶加速蛋白 (GAP)，可加速 Galpha 结合的 GTP 的水解，并促进非活性 Galpha GDP 的形成，从而关闭 GPCR 的信号传导。我们已经证明，RGS 蛋白可终止 MOR 至腺苷酸环化酶和 MAP 激酶途径的信号传导。另一方面，MOR 释放细胞内钙的有效信号需要 RGS 蛋白 GAP 活性。因此，RGS 活性控制着单个细胞内信号通路的平衡。我们最近使用了一种新工具来探索 RGS 蛋白对 GPCR 信号传导的调节：一种转基因敲入小鼠，其表达对 RGS 蛋白的 GAP 活性不敏感的 Galpha 蛋白。在这些小鼠中，镇痛作用取决于所使用的阿片类激动剂和疼痛测定。例如，在热板测定中，RGS 调节的丧失会增强吗啡，而不影响美沙酮的镇痛作用。相反，在尾部撤回试验中，去除 RGS 活性会降低吗啡和美沙酮的镇痛作用。这表明参与这两种行为的不同神经元通路对 RGS 蛋白作用表现出不同的敏感性。我们建议继续对这些小鼠进行探索，以解决有关 MOR 信号传导及其与镇痛作用的关系的一系列基本问题。例如：抗伤害测试之间的差异是否是由于 RGS 作用的位点特异性差异所致？观察到的激动剂差异的基础是什么？这些差异可以通过细胞信号传导水平的影响来解释吗？其他也使用 Galpha 蛋白的神经递质系统有何作用？更多临床相关的疼痛模型是否也受 RGS 蛋白调节？我们的总体概念框架如下：1）RGS 活性控制 GPCR 信号传导至多个途径的平衡，这种平衡可能在疼痛时被破坏；2）RGS 诱导的 MOR 介导的镇痛作用的变化可能反映了之间平衡的改变。神经递质系统，特别是伤害感受肽（NOP）系统。拟议的研究将增进我们对阿片类信号通路及其 RGS 蛋白调节的理解，并在行为改变的背景下解释这些作用。这项研究的结果可用于开发更好的镇痛药物。