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: 10348646
• 负责人: David P. Siderovski
• 金额: $ 35.98万
• 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/10348646
• 关键词: Ablation; Absence of pain sensation; Acute; Affect; Agonist; American; Amphetamines; Analgesics; Anxiety; Attenuated; Automobile Driving; Autoreceptors; Behavior; Biological Assay; Central Nervous System Diseases; Chronic; Clinical; Clinical Data; Cocaine; Complement; Complex; Corpus striatum structure; Cyclic AMP; Data; Detection; Disease; Dopamine; Dopamine D2 Receptor; Drug Addiction; Excision; Exhibits; Family member; Future; G-Protein-Coupled Receptors; GTP-Binding Protein Regulators; GTP-Binding Protein alpha Subunits, Gs; 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 Antagonist; Opioid Receptor; Opioid agonist; Outcome; Pathway interactions; Patients; Pattern; Pertussis Toxin; Pharmaceutical Preparations; Pharmacology; Physiological Processes; Population; Protein Family; Proteins; Pruritus; RGS Proteins; 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; addiction; base; behavioral outcome; beta-arrestin; chronic pain; chronic painful condition; clinically relevant; cost; dopamine transporter; dysphoria; in vivo; kappa opioid receptors; loss of function mutation; mRNA Expression; member; mu opioid receptors; novel; overexpression; pain relief; painful neuropathy; 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.

kappa 阿片受体 (KOR) 有助于介导对压力的反应，但也与发育和/或 维持慢性疼痛、毒瘾、焦虑和抑郁等健康障碍。 KOR 激动剂已显示 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-arrestin 信号传导被认为是其有害副作用（例如烦躁不安）的核心。然而，机制 KOR 下游的这些信号是通过什么来调节的，目前仍在阐明中。监管机构 G 蛋白信号转导是细胞内蛋白质，可加速 G 蛋白偶联受体后信号终止 激活。 RGS12 是该蛋白质家族的复杂成员，具有至少五个相互作用的不同结构域 具有 G 蛋白依赖性和非依赖性信号通路的成分。我们最近报道说 RGS12 在腹侧纹状体 (vSTR) 中富集，全局 Rgs12 消融会降低运动反应 多巴胺（DA）调节精神兴奋剂。我们的数据与增强型 DA 转运蛋白 (DAT) 相关 在 RGS12 缺失小鼠中，vSTR 而非背侧纹状体 (dSTR) 中存在表达和功能。 RGS12 丢失 （特别是作为 Gai/o 定向 GTP 酶加速蛋白）可能间接增加 DAT 表达/功能 鉴于 KOR 激动剂已知会增加 DAT，因此通过消除 KOR 下游的负调控 表面表达和摄取功能。支持这一概念的是增强的 DAT 功能和减少的 RGS12 缺失引起的 AMPH 刺激运动在 KOR 拮抗作用后均被逆转。我们也 发现 RGS12-null 和 β-arrestin2-null 小鼠品系的 vSTR 中 KOR 表达升高，但 dSTR 中没有升高。 RGS12 过表达会增强 β-arrestin 募集至激活的 KOR——这种效应在以下情况下得以保留 百日咳毒素介导的 Gi/o 抑制或 RGS12 Ga 相互作用域的突变，表明 G蛋白独立机制。这些发现与我们最新的数据一致，即 RGS12 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，我们的数据强调了 RGS12 作为 G 蛋白依赖的新型差异调节剂的作用。 -KOR 激活下游的独立信号传导，这是一种可利用的调节 药理学上有助于将 KOR 介导的信号转变成有益的结果，远离有害的结果。 我们的首要目标是确定 RGS12 在其中发挥调节 G 蛋白作用的特定神经元群体 依赖和独立的 KOR 信号传导，测试 RGS12 调节 KOR 的假设 DAT 专门在表达 KOR 和 DAT 的 CNS 神经元中发挥作用，并且也在脊髓水平上起作用 绳索。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 RGS12 和 KOR 之间。成功实现这两个目标将为考虑提供关键的临床前数据 RGS12 是未来参与 KOR 信号转导的镇痛和抗成瘾治疗的有效靶点。