The Potential Role of CRF Neurons in Mediating Onset of Stress-induced Susceptibility via PVT-BNST Connectivity

CRF 神经元通过 PVT-BNST 连接介导应激诱发的易感性发作的潜在作用

• 批准号: 9975633
• 负责人: SHEROD E HAYNES
• 金额: $ 5.05万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-07-10 至 2021-11-08
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9975633
• 关键词: Anhedonia; Animals; Arousal; Beds; Behavior; Behavioral; Buffers; Cell Nucleus; Cells; Chronic; Chronic stress; Corticotropin-Releasing Hormone; Corticotropin-Releasing Hormone Receptors; Cytoplasm; Data; Development; Dissection; Electrophysiology (science); Emotional; Equilibrium; Etiology; Exhibits; FOS gene; Functional Magnetic Resonance Imaging; Gene Expression; Genetic; Glutamates; Homeostasis; Human; Hyperactive behavior; Intercept; Label; Length; Light; Major Depressive Disorder; Mediating; Mental Depression; Mental disorders; Methods; Mission; Molecular; Molecular Target; Motivation; Mus; Neurons; Optics; Pathogenesis; Pathologic; Patients; Pattern; Phenotype; Play; Positron-Emission Tomography; Predisposing Factor; Predisposition; Prevalence; Property; Psychosocial Stress; Quantitative Reverse Transcriptase PCR; Rattus; Regulation; Reporting; Risk Factors; Role; Social Behavior; Social Interaction; Stress; Sucrose; Suggestion; Synapses; Testing; Thalamic structure; Time; Tissues; Transgenic Mice; Treatment Efficacy; United States National Institutes of Health; Viral Vector; acute stress; behavior test; behavioral response; biological adaptation to stress; burden of illness; cell type; depressive behavior; depressive symptoms; designer receptors exclusively activated by designer drugs; hedonic; imaging study; insight; interdisciplinary approach; mRNA Expression; motivated behavior; negative emotional state; neuronal excitability; new therapeutic target; novel; novel therapeutics; patch clamp; predictive marker; preference; psychosocial; relating to nervous system; release factor; response; selective expression; social; social defeat; stressor; transcriptomics; transgene expression

Project Summary Major Depressive Disorder (MDD) is the most common psychiatric disorder with a lifetime prevalence of 1 in 5, treatment for which is currently suboptimal. Deficits in ability to cope with ongoing chronic stressors are one of the chief predisposing factors to MDD. Neurons of the Paraventricular Thalamus (PVT) are critical in emotional arousal and orchestrate adaptive stress-relevant neurohumoral responses. Furthermore, a synaptic target of the PVT, the oval nucleus of the Bed Nucleus of the Stria Terminals (BNSTov), regulates behavioral responses to stress through Corticotropin-Releasing Factor (CRF)-releasing neurons. The PVT is critical in regulating relevant neurohumoral responses to chronic stress, thought to occur via CRF-neurons of a PVT-BNSTov circuit. Additionally, I have preliminary electrophysiological and single-cell qRT-PCR data in the rat and tissue micropunches in the mouse, that chronic stress accompanies increases in neuronal excitability and enhancement of crf and crf receptor 1 gene expression selectively in the BNSTov. Given that these cells are under direct PVT synaptic influence, this could represent a PVT-mediated adaptive response. Interestingly, unlike in acute stress, in chronic stress, PVT mediated adaptive neural responses appear to be temporally independent of the actual behavioral expression of that stress adaptation. Therefore, this PVT-BNSTov circuit may underlie the latency in the conversion of chronic stress into depressive-like behaviors. To determine the time course wherein stress-induced depressive-like behavior emerges, I employed the Chronic Social Defeat Stress (CSDS) paradigm in mice, and conducted social interaction/sucrose preference testing at various stress duration lengths of 4-10 days. I observed that between 7 and 10 days of CSDS, animals underwent a switch from social approach (“resilient”) to socially avoidant (“susceptible”) phenotypes. The electrophysiological and molecular substrates underlying this rapid behavioral shift remains unknown. I hypothesize that PVT-BNSTov connectivity may govern the temporal emergence of stress susceptibility in the face of persistent psychosocial stress, through PVT synaptic influence on CRF BNSTov neurons. I plan to investigate this functional PVT-BNSTov circuit using electrophysiological, single-cell transcriptomics, and advanced optical circuit dissection methods (DREADDs). First, I will establish functional connectivity by correlating tract tracing and c-Fos activity with the co-occurrence over the time period capturing the behavioral switch (aim 1). Then, I will record in ex-vivo whole-cell patch clamp the intrinsic neuronal properties and procure the cytoplasm for single-cell qRT-PCR analysis in cells before or after the behavioral transition (aim 2). Lastly, I will establish the necessity of the PVT-BNST circuit in mediating the temporal onset of susceptibility via time- and circuit-specific manipulations using DREADDs (aim 3). This proposed state-of-the-art circuit- and cell-type specific manipulations will provide novel insight into stress insult-dependent mechanisms that underlie MDD etiology, which will give rise to more effective therapeutic strategies for MDD.

项目概要 重度抑郁症 (MDD) 是最常见的精神疾病，一生患病率为五分之一， 目前治疗效果欠佳。应对持续的慢性压力源的能力缺陷是其中之一 MDD 的主要诱发因素。室旁丘脑 (PVT) 的神经元对于情绪调节至关重要 唤醒和协调适应性压力相关的神经体液反应。此外，突触目标 PVT，纹状末端床核 (BNSTov) 的卵圆核，调节行为反应 通过释放促肾上腺皮质激素释放因子（CRF）的神经元来缓解压力。 PVT 对于调节至关重要 对慢性应激的相关神经体液反应，被认为是通过 PVT-BNSTov 的 CRF 神经元发生的 电路。此外，我还有大鼠和组织的初步电生理学和单细胞 qRT-PCR 数据 小鼠体内的微穿孔表明，慢性应激会导致神经元兴奋性增加， BNSTov 中选择性增强 crf 和 crf 受体 1 基因表达。鉴于这些细胞是 在直接 PVT 突触影响下，这可能代表 PVT 介导的适应性反应。有趣的是， 与急性应激不同，在慢性应激中，PVT 介导的适应性神经反应似乎是暂时的 独立于压力适应的实际行为表达。因此，这个PVT-BNSTov电路 可能是慢性压力转化为抑郁样行为的潜伏期的基础。确定 当压力引起的抑郁样行为出现时，我采用了慢性社交失败 小鼠压力（CSDS）范例，并在各种压力下进行社交互动/蔗糖偏好测试 持续时间为4-10天。我观察到，在 CSDS 的 7 到 10 天之间，动物经历了转变 从社交方式（“弹性”）到社交回避（“易感”）表型。电生理学和 这种快速行为转变背后的分子底物仍然未知。我假设 PVT-BNSTov 面对持续的压力，连通性可能控制压力敏感性的时间出现 社会心理压力，通过 PVT 突触影响 CRF BNSTov 神经元。我打算调查此事 使用电生理学、单细胞转录组学和先进光学的功能性 PVT-BNSTov 电路 电路剖析方法（DREADD）。首先，我将通过关联路径追踪来建立功能连接 和 c-Fos 活动与捕获行为转换的时间段内的共现（目标 1）。然后，我 将在离体全细胞膜片钳中记录内在神经元特性并获取细胞质 在行为转变之前或之后对细胞进行单细胞 qRT-PCR 分析（目标 2）。最后，我将建立 PVT-BNST 电路通过时间和电路特定来调节易感性的时间发作的必要性 使用 DREADD 进行操作（目标 3）。这种提出的最先进的电路和单元类型特定 操作将为MDD病因学中的压力损伤依赖性机制提供新的见解， 这将为MDD带来更有效的治疗策略。