The role of RGS12 in differential modulation of G protein versus beta-arrestin signaling downstream of the kappa opioid receptor

RGS12 在 G 蛋白与 kappa 阿片受体下游 β-arrestin 信号传导的差异调节中的作用

• 批准号: 10535463
• 负责人: David P. Siderovski
• 金额: $ 35.97万
• 依托单位: UNIVERSITY OF NORTH TEXAS HLTH SCI CTR
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-02-15 至 2025-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10535463
• 关键词: Ablation; Absence of pain sensation; Acceleration; Acute; Affect; Agonist; American; Amphetamines; Analgesics; Anxiety; Attenuated; Automobile Driving; Autoreceptors; Behavior; Biological Assay; Central Nervous System Diseases; Chronic; Clinical; Cocaine; Complement; Complex; Corpus striatum structure; Cyclic AMP; Data; Data Correlations; Detection; Disease; Dopamine; Dopamine D2 Receptor; Drug Addiction; Excision; Exhibits; Family member; Future; G-Protein-Coupled Receptors; GTP-Binding Protein Regulators; GTP-Binding Proteins; Guanosine Triphosphate Phosphohydrolases; Health; Heterotrimeric GTP-Binding Proteins; Human; In Vitro; Individual; Intracellular Signaling Proteins; Knockout Mice; Locomotion; Measures; Mediating; Mental Depression; Molecular; Mouse Strains; Mus; Mutation; Nature; Neurons; Nociception; Opioid Receptor; Opioid agonist; Outcome; Pathway interactions; Patients; Pattern; Pertussis Toxin; Pharmaceutical Preparations; Physiological Processes; Population; Protein Family; Proteins; Pruritus; Receptor Activation; Receptor Signaling; Regulation; Reporting; Research; Role; Signal Pathway; Signal Transduction; Signaling Protein; Site-Directed Mutagenesis; Spinal; Spinal Cord; Stress; Surface; Testing; Therapeutic; Validation; Ventral Striatum; Vertebral column; addiction; antagonist; antinociception; behavioral outcome; beta-arrestin; chronic pain; chronic painful condition; clinically relevant; dopamine transporter; dysphoria; economic cost; health economics; in vivo; kappa opioid receptors; loss of function mutation; mRNA Expression; member; mu opioid receptors; novel; overexpression; pain relief; painful neuropathy; pharmacologic; pre-clinical; preservation; presynaptic; protein activation; psychostimulant; public health relevance; receptor; receptor expression; receptor-mediated signaling; recruit; response; reuptake; side effect; socioeconomics; success; uptake

The kappa opioid receptor (KOR) helps mediate responses to stress, yet is also implicated in developing and/or maintaining health disorders of chronic pain, drug addiction, anxiety and depression. KOR agonists have shown promise in ameliorating these disorders, but are limited by dysphoric side effects. Beneficial effects of KOR agonists (e.g., analgesia) are considered predominantly mediated by G protein signaling, whereas β-arrestin signaling is considered central to their detrimental side effects (e.g., dysphoria). However, the mechanism(s) by which these signals downstream of KOR are regulated are still being elucidated. The Regulators of G protein Signaling are intracellular proteins that accelerate signal termination after G protein-coupled receptor activation. RGS12 is a complex member of this protein family, with at least five different domains that interact with components of both G protein-dependent and -independent signaling pathways. We recently reported that RGS12 is enriched in the ventral striatum (vSTR), and global Rgs12 ablation decreases locomotor responses to dopamine (DA)-modulating psychostimulants. Our data correlate with the augmented DA transporter (DAT) expression and function in the vSTR, but not dorsal striatum (dSTR), seen in RGS12-null mice. Loss of RGS12 (especially as a Gai/o-directed GTPase-accelerating protein) may indirectly increase DAT expression / function by removing negative regulation downstream of KOR, given that KOR agonists are known to increase DAT surface expression and uptake function. Supporting this notion, the augmented DAT function and reduced AMPH-stimulated locomotion caused by RGS12 loss are both reversed following KOR antagonism. We also found elevated KOR expression in the vSTR, but not dSTR, of RGS12-null and β-arrestin2-null mouse strains. RGS12 over-expression augments β-arrestin recruitment to activated KOR – an effect preserved following pertussis toxin-mediated Gi/o inhibition or mutation to the Ga-interacting domains of RGS12, suggesting a G protein-independent mechanism. These findings are consistent with our newest data that RGS12-null mice exhibit attenuated KOR agonist-induced conditioned place aversion, considered β-arrestin-dependent behavior. Collectively, our data highlight a role for RGS12 as a novel, differential regulator of both G protein-dependent and -independent signaling downstream of KOR activation, a regulation that may be exploitable pharmacologically to help shift KOR-mediated signaling to beneficial outcomes and away from detrimental ones. Our first aim is to determine the specific neuronal populations within which RGS12 acts to modulate G protein- dependent and -independent KOR signaling, testing hypotheses that RGS12 operates to modulate KOR and DAT function specifically in KOR- and DAT- expressing CNS neurons, and also operates at the level of the spinal cord. Our second aim is to delineate the molecular determinants that engender selective functional interactions between RGS12 and KOR. Success in pursuit of these two aims will provide key pre-clinical data for considering RGS12 a valid target for future analgesic and anti-addiction therapeutics that engage KOR signal transduction.

κ阿片受体（KOR）有助于介导对压力的反应，但也涉及发展和/或 维持健康的慢性疼痛，吸毒成瘾，焦虑和抑郁症的障碍。KOR激动剂已经显示 有望改善这些疾病，但受到烦躁副作用的限制。KOR的有益效果 激动剂（例如，镇痛）被认为主要由G蛋白信号传导介导，而β-抑制蛋白 信号传导被认为是其有害副作用的中心（例如，烦躁不安）。然而，机制 通过什么来调节KOR下游的这些信号仍在阐明中。的监管机构 G蛋白信号转导蛋白是G蛋白偶联受体介导的细胞内信号转导蛋白 activation. RGS 12是该蛋白质家族的复杂成员，具有至少五个不同的相互作用结构域 具有G蛋白依赖性和非依赖性信号通路的组分。我们最近报道说， RGS 12在腹侧纹状体（vSTR）中富集，并且整体Rgs 12消融降低了对运动的运动反应。 多巴胺（DA）调节精神兴奋剂。我们的数据与增强DA转运蛋白（DAT） 在RGS 12缺失小鼠中观察到vSTR中的表达和功能，而不是背侧纹状体（dSTR）。RGS 12缺失 （特别是作为Gai/o指导的GTP酶加速蛋白）可能间接增加DAT表达/功能 通过去除KOR下游的负调节，已知KOR激动剂增加DAT， 表面表达和摄取功能。支持这一概念，增强的DAT函数和减少的 由RGS 12损失引起的AMPH刺激的运动在KOR拮抗作用后都被逆转。我们也 发现RGS 12-null和β-arrestin 2-null小鼠品系的vSTR中KOR表达升高，但dSTR中没有。 RGS 12过表达增加β-arrestin向激活的KOR的募集-在以下情况下保留的效果 百日咳毒素介导的Gi/o抑制或RGS 12的Ga相互作用结构域的突变，表明 G蛋白非依赖性机制。这些发现与我们的最新数据一致，即RGS 12缺失小鼠 表现出减弱的KOR激动剂诱导的条件性位置厌恶，被认为是β-抑制蛋白依赖性行为。 总的来说，我们的数据突出了RGS 12作为一种新的，G蛋白依赖的差异调节剂的作用。 和KOR激活下游的非依赖性信号传导，这是一种可能被利用的调节， 这有助于将KOR介导的信号传导转变为有益的结果，远离有害的结果。 我们的第一个目标是确定特定的神经元群体，其中RGS 12起作用以调节G蛋白。 依赖性和非依赖性KOR信号传导，测试RGS 12调节KOR的假设， DAT在表达KOR和DAT的CNS神经元中特异性地起作用，并且还在脊髓水平起作用。 线.我们的第二个目标是描述产生选择性功能相互作用的分子决定因素 RGS 12和KOR之间的关系。这两个目标的成功实现将提供关键的临床前数据， RGS 12是参与KOR信号转导的未来镇痛和抗成瘾治疗的有效靶标。