Role for novel ventral tegmental area neuromedin S neurons in morphine responses

新型腹侧被盖区神经调节素 S 神经元在吗啡反应中的作用

• 批准号: 10739543
• 负责人: Michelle Suzanne Mazei-Robison
• 金额: $ 22.76万
• 依托单位: MICHIGAN STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-06-15 至 2025-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10739543
• 关键词: Adult; Affect; Afferent Neurons; Affinity Chromatography; Behavior; Behavioral; Biological Assay; CRISPR/Cas technology; Cells; Characteristics; Chronic; Clozapine; Clustered Regularly Interspaced Short Palindromic Repeats; Data; Data Set; Diagnostic; Dopamine; Drug Addiction; Drug usage; Economic Burden; Exhibits; Future; Gene Expression; Genes; Goals; Health; Hippocampus; Hormone Responsive; Hypothalamic Hormones; Intervention; Intraperitoneal Injections; Knock-out; Mediating; Molecular; Morphine; Mus; Names; National Institute of Drug Abuse; Neurobiology; Neurons; Neuropeptides; Nucleus Accumbens; Opiate Addiction; Opioid; Output; Oxides; Pharmaceutical Preparations; Physiological; Population; Production; Property; Reagent; Reporting; Rewards; Ribosomes; Role; Site; Structure; Therapeutic Intervention; Tissues; Transgenic Mice; Translating; Ventral Tegmental Area; Viral Vector; Work; addiction; behavioral response; cell type; circadian regulation; conditioned place preference; design; designer receptors exclusively activated by designer drugs; dopaminergic neuron; drug reward; improved; insight; interest; motivated behavior; neurochemistry; neuromedin U receptor; neurotransmitter release; novel; pharmacologic; receptor; receptor expression; response; reward circuitry; sensory cortex; suprachiasmatic nucleus; targeted treatment; transcriptome sequencing

Summary Although opioid dependence and addiction continue to constitute a major health and economic burden, our limited understanding of the underlying neurobiology limits better diagnostics and interventions. Dysregulation of the mesocorticolimbic reward circuit is acknowledged to contribute to various aspects of drug addiction, with alteration in the activity and output of dopamine (DA) neurons in the ventral tegmental area (VTA) known to contribute to the rewarding aspects of drug use. However, the molecular mechanisms underlying these changes in VTA DA function remain relatively unexplored. Therefore, our overarching goal is to identify molecular mechanisms in VTA DA neurons mediating long-term changes in drug reward that contribute to the persistence of drug addiction. To this end, we used translating ribosome affinity purification (TRAP) to identify gene expression changes in mice that specifically occur in VTA DA neurons following chronic morphine exposure. While we found approximately the same number of gene expression changes by morphine in our input and VTA DA fractions, our RNA sequencing analysis found very little overlap between these datasets emphasizing the importance of this approach to identify mechanisms in VTA DA neurons as these are likely obscured in whole tissue analyses. We have validated gene expression changes via qPCR and intriguingly, we find that expression of number of neuropeptides not traditionally described in the VTA are robustly induced by morphine exposure. Neuromedin S (NMS) was of particular interest as it was enriched in VTA DA neurons, and its expression was robustly increased following chronic morphine exposure. While a role for NMS neurons has been described in the suprachiasmatic nucleus in circadian regulation, NMS function outside this structure has not been characterized, making it a highly novel gene of study. It is known that the primary receptor with which NMS interacts, neuromedin U receptor 2 (NMUR2), is expressed within the target regions of VTA DA neurons, such as the nucleus accumbens (NAc). However, whether all VTA DA neurons express NMS, and their potential functional impact has yet to be determined. Thus, in this application we seek to characterize the expression and functional impact of VTA DA neurons that co-express NMS via completion of three specific aims: 1) identify the VTA DA neurons that express NMS and their projection sites, 2) determine whether modulation of VTA NMS neuronal activity alters morphine-elicited behavior, and 3) determine if NMS knockout in VTA DA neurons alters morphine-elicited behavior. Our studies will utilize cell type-specific CRISPR-mediated deletion to manipulate the output of these novel VTA NMS-expressing neurons to assess their functional role in adult mice along with transgenic mice and DREADDs to identify and alter VTA-NMS neuron activity. Critically, our new preliminary data suggest that activation of VTA-NMS neurons affects morphine-elicited behavior, supporting the premise and feasibility. These studies are expected to set the stage for future work investigating the role of specific VTA- DANMS circuits, their activity during behavior, and their potential as targets for therapeutic intervention.

概括 尽管阿片类药物依赖和成瘾继续构成重大的健康和经济负担，但我们 对潜在神经生物学的了解有限限制了更好的诊断和干预。失调 中皮质边缘奖赏回路的功能被认为与药物成瘾的各个方面有关，其中 已知腹侧被盖区 (VTA) 多巴胺 (DA) 神经元的活动和输出发生变化 有助于药物使用的有益方面。然而，这些变化背后的分子机制 VTA 中的 DA 功能仍然相对未被探索。因此，我们的首要目标是识别分子 VTA DA神经元的机制介导药物奖励的长期变化，从而有助于持久性 的毒瘾。为此，我们使用翻译核糖体亲和纯化（TRAP）来鉴定基因 小鼠慢性吗啡暴露后，VTA DA 神经元中特异发生的表达变化。 虽然我们发现吗啡在我们的输入和 VTA 中引起的基因表达变化数量大致相同 DA 分数，我们的 RNA 测序分析发现这些数据集之间几乎没有重叠，强调 这种方法对于识别 VTA DA 神经元机制的重要性，因为这些神经元可能完全被掩盖 组织分析。我们通过 qPCR 验证了基因表达变化，有趣的是，我们发现表达 吗啡暴露会强烈诱导 VTA 中传统上未描述的神经肽数量。 Neuromedin S (NMS) 特别令人感兴趣，因为它富含 VTA DA 神经元，并且其表达量为 慢性吗啡暴露后急剧增加。虽然 NMS 神经元的作用已在 视交叉上核在昼夜节律调节中的作用，该结构之外的 NMS 功能尚未被研究 特征，使其成为一个高度新颖的研究基因。众所周知，NMS 的主要受体 神经调节素 U 受体 2 (NMUR2) 相互作用，在 VTA DA 神经元的目标区域内表达，例如 作为伏隔核（NAc）。然而，是否所有 VTA DA 神经元都表达 NMS，以及它们的潜力 功能影响尚未确定。因此，在本应用中，我们试图表征表达式和 通过完成三个特定目标来共同表达 NMS 的 VTA DA 神经元的功能影响：1）确定 表达 NMS 的 VTA DA 神经元及其投射位点，2) 决定是否调节 VTA NMS 神经元活动改变吗啡引发的行为，3) 确定 VTA DA 神经元中的 NMS 敲除是否会改变 吗啡引起的行为。我们的研究将利用细胞类型特异性 CRISPR 介导的缺失来操纵 这些新型 VTA NMS 表达神经元的输出，以评估它们在成年小鼠中的功能作用以及 转基因小鼠和 DREADD 来识别和改变 VTA-NMS 神经元活动。至关重要的是，我们的新初步 数据表明 VTA-NMS 神经元的激活会影响吗啡引发的行为，支持了这一前提 和可行性。这些研究预计将为未来调查特定 VTA 作用的工作奠定基础 DANMS 回路、它们在行为过程中的活动以及它们作为治疗干预目标的潜力。