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 尽管阿片类药物的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有限理解限制了更好的诊断和干预措施。失调 中皮质质奖励电路被承认有助于吸毒的各个方面 已知的腹侧对段区域（VTA）中多巴胺（DA）神经元的活性和输出的改变 有助于吸毒的有益方面。但是，这些变化的分子机制 在VTA中，DA函数仍然相对未开发。因此，我们的总体目标是确定分子 VTA DA神经元中的机制介导了有助于持久性的药物奖励的长期变化 吸毒成瘾。为此，我们使用翻译核糖体亲和力纯化（TRAP）来识别基因 慢性吗啡暴露后VTA DA神经元中特异性发生的小鼠的表达变化。 虽然我们发现我们的输入和VTA中吗啡的基因表达大约相同数量的基因表达变化 DA分数，我们的RNA测序分析发现这些数据集之间的重叠很少，强调了 这种方法的重要性是识别VTA DA神经元中的机制，因为这些方法可能总体上被遮盖了 组织分析。我们已经通过qPCR验证了基因表达的变化，并且很有趣，我们发现了表达 vTA中不传统上描述的神经肽数量是由吗啡暴露强烈诱导的。 神经蛋白（NMS）特别感兴趣，因为它富含VTA DA神经元，其表达为 慢性吗啡暴露后，强劲增加。虽然已经描述了NMS神经元的角色 昼夜节律调节中的上核核，在该结构之外的NMS功能尚未是 表征，使其成为高度新颖的研究基因。众所周知，NMS的主要受体 相互作用，神经蛋白U受体2（NMUR2）在VTA DA神经元的目标区域内表达 作为伏隔核（NAC）。但是，是否所有VTA DA神经元表达NM及其潜力 功能影响尚未确定。因此，在此应用中，我们试图表征表达式和 通过完成三个特定目的共表达NM的VTA DA神经元的功能影响：1）确定 表达NMS及其投影位点的VTA DA神经元，2）确定是否调制VTA NMS 神经元活性改变了吗啡吸引的行为，3）确定VTA DA神经元中的NMS敲除是否改变 吗啡引诱行为。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神经元的输出评估其在成年小鼠中的功能作用以及 转基因小鼠和恐惧识别和改变VTA-NMS神经元活性。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诱的行为，支持前提 和可行性。这些研究有望为未来的工作奠定阶段，以调查特定VTA-的作用 Danms电路，行为过程中的活动以及作为治疗干预目标的潜力。