Peptide Receptor Systems

肽受体系统

基本信息

批准号：
9357264
负责人：
Ted B Usdin
金额：
$ 110.11万
依托单位：
NATIONAL INSTITUTE OF MENTAL HEALTH
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/9357264
关键词：
Ablation Acute Pain Adult Affect Aggressive behavior Amygdaloid structure Animals Anxiety Area Aversive Stimulus Behavior Behavioral Biochemical Biological Brain Brain Stem Brain region California Cell Nucleus Cells Cognitive Corticotropin-Releasing Hormone Data Drug usage Emotional Emotions Environment Event Excision FOS gene Freezing Fright Gene Mutation Genes Glutamates Goals Half-Life Hippocampus (Brain)Human Hypothalamic structure Impairment Intervention Investigation Knockout Mice Knowledge Laboratories Lead Link Location Maps Maternal Behavior Measures Medial Memory Mental Depression Mental disorders Modeling Molecular Target Mood Disorders Moods Mus Nerve Neurons Neuropathy Neuropeptides Neurosecretory Systems Nociception Pain Parathyroid Hormone Receptor 2 Pathway interactions Pattern Peptide Receptor Peptides Pharmaceutical Preparations Pharmacogenetics Pharmacotherapy Phenotype Physiological Play Population Post-Traumatic Stress Disorders Process Psychotropic Drugs Regulation Reporting Resolution Rodent Role Sensory Shock Signal Transduction Site Skin Spinal cord posterior horn Stimulus Stress Swimming Symptoms System Tactile Testing Thalamic structure Time Treatment Efficacy Universities Virus Work activity marker adult neurogenesis alcohol effect allodynia anxiety-like behavior base behavioral response chronic pain design designer receptors exclusively activated by designer drugs diphtheria toxin receptor environmental change fast-acting neurotransmitter fear memory foot gene function hormone regulation insight keratinocyte locus ceruleus structure male neurochemistry neurogenesis neuroregulation noradrenergic novel object recognition painful neuropathy performance tests prevent receptor recombinase reduce symptoms research study resilience response sciatic nerve sensory input sensory stimulus social stressor targeted delivery therapeutic target transmission process traumatic event

项目摘要

Following discovery of the neuropeptide Tuberoinfundibular Peptide of 39 residues (TIP39) and its receptor, the Parathyroid Hormone Receptor 2 (PTH2R) the section focused on investigation of their biological roles. Neuroanatomical mapping showed synthesis of TIP39 in discrete neuronal groups in the thalamus and brainstem that project to brain areas involved in emotional function. Following its anatomical mapping, laboratory projects turned to investigation of hypotheses derived from the distribution of the PTH2R/TIP39 system. Findings include that TIP39 modulates activation of hypothalamic neuroendocrine neurons including that it is important for an appropriate homeostatic response to cold. These studies lead to a general model for TIP39 action, that activation of PTH2Rs may be necessary for robust and sufficient excitatory transmitter release under high demand conditions. TIP39 was also found to modulate both acute pain sensitivity, and the return to normal sensitivity in chronic pain models. The latter effect appears to involve the locus coeruleus, a brainstem nucleus that contains noradrenergic neurons with modulatory influence throughout the CNS. In combination with other observations this suggests that TIP39 may be one of the modulators involved in the relationship between sensory stimuli and mood. Difficulty distinguishing between effects of ongoing aversive sensory input and its long-term consequences is a significant roadblock to investigating relationships between sensory stimuli and mood. To overcome this limitation we developed a paradigm to compare cellular and behavioral changes during and after reversing neuropathic pain in mice. Tactile allodynia and neuronal activation in the spinal cord dorsal horn produced by a cuff placed around the sciatic nerve resolved within several days following cuff removal. In contrast, changes in elevated O-maze, forced-swim, Y-maze spontaneous alternation and novel-object recognition test performance that developed after nerve cuff placement persisted at least 3 weeks after nerve cuffs were removed. Thus anxiety- and depression-like behaviors persisted following apparent resolution of pain in this paradigm. One contemporary idea regarding the cellular changes underlying depression is that inhibition of normal adult neurogenesis plays a role. Adult hippocampal neurogenesis is inhibited in chronic pain models, suggesting that neurogenesis inhibition may be involved in chronic pain associated depression. Using the reversible neuropathic model we found that adult hippocampal neurogenesis was decreased for at least 3 weeks following pain resolution. Also, FosB, a neuronal activity marker with a long half-life, remained elevated in the basolateral amygdala of mice with resolved nociception and persisting behavioral effects. Thus the reversible neuropathic paradigm points to specific cellular phenotypes that can be used to elucidate links between nociceptive sensory signaling and mood disorders. Previously, we found that mice with inactivating mutations of the genes encoding TIP39 (TIP39-KO) or the PTH2R (PTH2R-KO) have increased anxiety-like behavior under stressful conditions, relative to wild-type. Mice without TIP39 signaling have increased stress-dependent impairment in tests of memory function. Dysfunctional responses to stress are widely thought to contribute to depression, implying that this neuropeptide system plays a role in normal resilience. We investigated TIP39/PTH2R contributions to long-term fear memory using a model of post-traumatic stress disorder (PTSD) in which mice are exposed to a single aversive stimulus (foot-shock), after which fear memory is evaluated by measuring the time spent motionless (freezing, a rodent fear-like response) when the animals are re-exposed to the specific environment (fear context) in which the stimulus was delivered. While absence of TIP39 signaling did not cause a detectable change in fear memory 1 week after shock, both TIP39-KO and PTH2R-KO mice had increased fear-like behavior in the fear context after 2 and 4 weeks. Increasing in fear memory over time following a fear-inducing event is called fear incubation. Based on similarity to delayed symptom onset that frequently occurs in PTSD, fear incubation is used to investigate mechanisms that may contribute to PTSD. Thus, we investigated the neuroanatomical basis for enhanced fear incubation in mice that lack TIP39 signaling. Comparing neuronal activation patterns between mice with and without TIP39 signaling, either immediately after foot-shock or 4 weeks later when animals were returned to the fear context, revealed that TIP39 signaling absense prevented the normal activation of c-Fos in the medial nucleus of the amygdala (MeA). We used a PTH2R antagonist and mice that express Cre-recombinase in neurons that normally contain PTH2Rs, which we previously developed, to investigate whether the TIP39/PTH2R system in the MeA is responsible for the enhanced fear incubation. MeA targeted delivery of a virus encoded PTH2R antagonist reproduced the enhanced fear incubation of the KO mice. Selective ablation of MeA neurons that normally synthesize PTH2Rs following stereotaxic delivery of a virus Cre-dependently encoding a diphtheria toxin receptor also led to enhanced fear incubation. Transient inhibition of MeA PTH2R expressing neurons using a virally delivered Cre-recombinase dependent Designer Receptor Exclusively Activated by Designer Drugs (DREADD), starting just before or just after foot-shock, or at the time of recall testing 1 month later showed that inhibiting PTH2R neurons near the time of the event but not at the time of recall testing caused enhanced fear incubation. Putting these observations together, these experiments showed for the first time that the state of the medial nucleus of the amygdala just after a traumatic event has a major effect on fear-like behavior a month later. It further shows that signaling by a neuropeptide can have a major effect on that state. Ongoing work examines contributions of TIP39 signaling in the medial nucleus of the amygdala to other behaviors. Based on decreased inter-male aggressive behavior and increased social investigative behavior by PTH2R-KO mice, and similar effects following pharmacogenetic inhibition of medial amygdalar PTH2R expressing neurons the system appears to play a significant role in selection of social responses. Several previous studies provide evidence that that TIP39 signaling influences maternal behavior. Work with Arpad Dobolyi (Etvs Lornd University) during this reporting period provided anatomical evidence that TIP39 neurons in the thalamic subparafascicular area relay suckling related information to the hypothalamus to affect maternal behaviors. New work with Richard Gallo (University of California San Diego) showed that both TIP39 and the PTH2R are expressed at high levels in populations of cells within the skin, and implied that the system regulates keratinocyte function. Danny Winder (Vanderbilt University) used a virus we made that Cre-dependently expresses the human diphtheria toxin receptor to selectively ablate corticotrophin-releasing factor (CRF) expressing neurons in the central amygdala and show that CRF dependent effects of ethanol on glutamatergic transmission do not depend on the presence of local CRF neurons. Overall, our data suggest that TIP39 signaling may normally limit detrimental effects of environmental stress on emotional state. Dysfunctional responses to stress are widely thought to contribute to depression, implying that this neuropeptide system plays a role in normal resilience.

在发现 39 个残基的神经肽结节漏斗肽 (TIP39) 及其受体甲状旁腺激素受体 2 (PTH2R) 后，本节重点研究其生物学作用。神经解剖图显示 TIP39 在丘脑和脑干的离散神经元群中合成，这些神经元群投射到涉及情绪功能的大脑区域。在完成解剖图绘制后，实验室项目转而研究源自 PTH2R/TIP39 系统分布的假设。研究结果包括 TIP39 调节下丘脑神经内分泌神经元的激活，包括它对于对寒冷做出适当的稳态反应很重要。这些研究得出了 TIP39 作用的通用模型，即 PTH2R 的激活可能是高需求条件下稳健和充分的兴奋性递质释放所必需的。 TIP39 还被发现可以调节急性疼痛敏感性，并在慢性疼痛模型中恢复正常敏感性。后一种效应似乎涉及蓝斑，这是一种脑干核，含有去甲肾上腺素能神经元，对整个中枢神经系统具有调节作用。与其他观察结果相结合，这表明 TIP39 可能是参与感觉刺激和情绪之间关系的调节剂之一。难以区分持续的厌恶性感官输入的影响及其长期后果是研究感官刺激与情绪之间关系的一个重大障碍。为了克服这一限制，我们开发了一种范例来比较小鼠逆转神经性疼痛期间和之后的细胞和行为变化。放置在坐骨神经周围的袖带产生的触觉异常性疼痛和脊髓背角神经元激活在移除袖带后几天内消失。相比之下，放置神经袖带后出现的高架 O 迷宫、强迫游泳、Y 迷宫自发交替和新物体识别测试表现的变化在神经袖带移除后持续至少 3 周。因此，在这种范式中，在疼痛明显缓解后，类似焦虑和抑郁的行为仍然存在。关于抑郁症背后的细胞变化的一个当代观点是，正常成人神经发生的抑制发挥了作用。成人海马神经发生在慢性疼痛模型中受到抑制，表明神经发生抑制可能与慢性疼痛相关的抑郁症有关。使用可逆神经病理模型，我们发现成人海马神经发生在疼痛缓解后至少 3 周内减少。此外，FosB（一种半衰期较长的神经元活动标记物）在小鼠基底外侧杏仁核中保持升高，并具有解决的伤害感受和持续的行为影响。因此，可逆神经病理范式指向特定的细胞表型，可用于阐明伤害性感觉信号传导与情绪障碍之间的联系。此前，我们发现，与野生型相比，TIP39 (TIP39-KO) 或 PTH2R (PTH2R-KO) 编码基因失活突变的小鼠在压力条件下的焦虑样行为增加。没有 TIP39 信号传导的小鼠在记忆功能测试中应激依赖性损伤增加。人们普遍认为，对压力的功能失调会导致抑郁症，这意味着这种神经肽系统在正常的恢复能力中发挥着作用。我们使用创伤后应激障碍 (PTSD) 模型研究了 TIP39/PTH2R 对长期恐惧记忆的贡献，其中小鼠受到单一厌恶刺激（足部电击），之后通过测量时间来评估恐惧记忆当动物重新暴露于刺激传递的特定环境（恐惧环境）时，它们会一动不动（冻结，一种类似啮齿类动物的恐惧反应）。虽然TIP39信号传导的缺失并未导致休克后1周的恐惧记忆发生可检测到的变化，但TIP39-KO和PTH2R-KO小鼠在2周和4周后在恐惧环境中的恐惧样行为有所增加。在引发恐惧的事件之后，恐惧记忆会随着时间的推移而增加，这被称为恐惧孵化。基于与 PTSD 中经常发生的延迟症状发作的相似性，恐惧孵化可用于研究可能导致 PTSD 的机制。因此，我们研究了缺乏 TIP39 信号传导的小鼠恐惧孵化增强的神经解剖学基础。比较有和没有 TIP39 信号传导的小鼠之间的神经元激活模式，无论是在足部电击后立即还是在 4 周后当动物返回恐惧环境时，发现 TIP39 信号传导缺失阻止了内侧核中 c-Fos 的正常激活。杏仁核（MeA）。我们使用 PTH2R 拮抗剂和在通常含有 PTH2R 的神经元中表达 Cre 重组酶的小鼠（我们之前开发的）来研究 MeA 中的 TIP39/PTH2R 系统是否负责增强恐惧孵化。 MeA 靶向递送编码 PTH2R 拮抗剂的病毒，重现了 KO 小鼠的增强恐惧潜伏期。在立体定向递送依赖于 Cre 编码白喉毒素受体的病毒后，选择性消融通常合成 PTH2R 的 MeA 神经元也会导致恐惧潜伏期增强。使用病毒传递的 Cre 重组酶依赖性设计受体（DREADD）对表达 MeA PTH2R 的神经元进行瞬时抑制，在足部电击之前或之后开始，或在 1 个月后的回忆测试时显示，抑制 PTH2R接近事件发生时间但不在回忆测试时间的神经元会导致恐惧潜伏期增强。将这些观察结果放在一起，这些实验首次表明，创伤事件发生后杏仁核内侧核的状态对一个月后的恐惧样行为有重大影响。它进一步表明神经肽的信号传导可以对该状态产生重大影响。正在进行的工作检查杏仁核内侧核中 TIP39 信号传导对其他行为的贡献。基于 PTH2R-KO 小鼠雄性间攻击行为的减少和社会调查行为的增加，以及内侧杏仁核 PTH2R 表达神经元的药物遗传学抑制后的类似效果，该系统似乎在社会反应的选择中发挥着重要作用。之前的几项研究提供的证据表明，TIP39 信号传导会影响母亲的行为。在本报告期间与 Arpad Dobolyi（Etvs Lornd 大学）的合作提供了解剖学证据，表明丘脑束旁下区域的 TIP39 神经元将哺乳相关信息传递到下丘脑以影响母亲行为。 Richard Gallo（加州大学圣地亚哥分校）的新研究表明，TIP39 和 PTH2R 在皮肤细胞群中均高水平表达，并暗示该系统调节角质形成细胞功能。 Danny Winder（范德比尔特大学）使用我们制造的一种病毒，该病毒依赖于 Cre 表达人类白喉毒素受体，选择性地消除中央杏仁核中表达促肾上腺皮质激素释放因子 (CRF) 的神经元，并表明乙醇对谷氨酸能传递的 CRF 依赖性影响并不存在。取决于局部 CRF 神经元的存在。总体而言，我们的数据表明 TIP39 信号传导通常可以限制环境压力对情绪状态的有害影响。人们普遍认为，对压力的功能失调会导致抑郁症，这意味着这种神经肽系统在正常的恢复能力中发挥着作用。