Peptide Receptor Systems

肽受体系统

• 批准号: 8745691
• 负责人: Ted B Usdin
• 金额: $ 193.54万
• 依托单位: NATIONAL INSTITUTE OF MENTAL HEALTH
• 依托单位国家: 美国
• 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/8745691
• 关键词: Ablation; Acute; Acute Pain; Address; Adrenal Glands; Adrenergic Receptor; Affect; Affective; Animals; Anxiety; Area; Arousal; Behavior; Behavioral; Biochemical; Brain; Brain Diseases; Brain Stem; Brain region; Cell Nucleus; Chemicals; Cognitive; Corticosterone; Data; Development; Dimensions; Drug usage; Emotional; Emotions; Environment; Event; Exhibits; Freezing; Fright; Future; Gene Deletion; Gene-Modified; Genes; Genetic; Glucocorticoids; Glutamates; Goals; Healed; Hormones; Human; Hypersensitivity; Hypothalamic structure; Inflammatory; Injection of therapeutic agent; Injury; Interneurons; Intervention; Investigation; Knockout Mice; Knowledge; Laboratories; Lead; Ligands; Location; Maintenance; Maps; Measures; Medial; Memory; Mental Depression; Mental disorders; Modeling; Molecular Target; Mood Disorders; Moods; Mouse Strains; Mus; Mutation; Neuroendocrine Cell; Neuromodulator; Neurons; Neuropathy; Neuropeptides; Neuroregulator; Neurosecretory Systems; Norepinephrine; Pain; Pain Disorder; Parathyroid Hormone Receptor 2; Parathyroid gland; Pathway interactions; Peptide Receptor; Peptides; Performance; Pharmaceutical Preparations; Physiologic Thermoregulation; Physiological; Population; Positioning Attribute; Post-Traumatic Stress Disorders; Process; Production; Prosencephalon; Psychotropic Drugs; Reagent; Recovery; Regulation; Research; Rodent; Role; Sensory; Sensory Thresholds; Shock; Signal Transduction; Site; Source; Stress; Subfamily lentivirinae; Symptoms; System; Tactile; Temperature; Testing; Thalamic structure; Time; Transgenic Mice; Treatment Efficacy; Virus; Wild Type Mouse; barley lectin; behavior test; biological adaptation to stress; central sensitization; chronic depression; chronic pain; cognitive function; density; design; environmental change; fast-acting neurotransmitter; foot; gamma-Aminobutyric Acid; gene function; healing; hormone regulation; insight; interest; locus ceruleus structure; mouse model; nerve injury; nerve supply; neurochemistry; noradrenergic; null mutation; object recognition; painful neuropathy; paraventricular nucleus; preoptic nucleus; presynaptic; receptor; recombinant virus; recombinase; response; social; stressor; therapeutic target; transmission process; tuberoinfundibular peptide 39; vpr Genes

Summary: Investigation of the physiological functions of the neuropeptide Tuberoinfundibular Peptide of 39 residues (TIP39) and its receptor, the Parathyroid Hormone 2 (PTH2) receptor has been a recent focus of the laboratory. These molecules were discovered in this laboratory several years ago. In previous project years we mapped the neuroanatomical distributions of TIP39 and the PTH2 receptor. TIP39 is synthesized by 3 discrete groups of neurons, 2 at the caudal border of the thalamus and one in the brainstem. TIP39 synthesizing neurons project to several brain areas that are involved in the regulation of emotional function. These areas contain a matching distribution of the PTH2 receptor, and neurons in these regions project to the areas containing TIP39 neurons. Thus the system is ideally positioned to coordinate and modulate functions relevant to mental disorders. Following this anatomical mapping, laboratory projects turned to investigation of hypotheses derived from the distribution of TIP39 and the PTH2R. The hypothalamus contains a relatively high density of PTH2Rs and TIP39 containing terminals. In previous project years we found that TIP39 modulates activation of neurons in the hypothalamic paraventricular nucleus, which controls several neuroendocrine functions, including release of glucocorticoid stress hormones from the adrenal gland (corticosterone in rodents). TIP39 does this by acting on the terminals of neurons within the paraventricular nucleus that release the classic fast-acting transmitter glutamate. Thus TIP39 modulates excitatory inputs to neuroendocrine cells. We also found that TIP39 signaling in another hypothalamic region, the median preoptic nucleus, contributes to thermoregulation. Specifically, an appropriate homeostatic response to cold exposure required TIP39 signaling, while maintenance of a normal baseline temperature in an environment to which mice were adapted did not. These studies lead to the general model that TIP39 action on presynaptic PTH2Rs on some populations of glutamatergic neurons may be necessary for robust and sufficient excitatory transmitter release under particular high demand conditions. In previous years of the project we found that mice with genetic deletion of the gene encoding TIP39 (TIP39-KO) have increased anxiety-like behavior that depends upon the level of stress created by the testing conditions. Under conditions of minimal stress, loss of TIP39 had little effect, while under increased stress animals without TIP39 exhibited significantly greater anxiety-like behavior than mice with normal TIP39 function. We also investigated the role of TIP39 in modulating the effects of stress on cognitive function. Mice lacking TIP39 signaling because of either ligand or receptor loss or acute receptor blockade showed impaired performance in behavioral tests that depend on memory function (object recognition and social recognition tests and spontaneous alternation in a Y-maze), under conditions of novelty-induced arousal but not when acclimated to the testing environment. We also found that TIP39 signaling modulates long-term emotional memory. In a mouse model of post-traumatic stress disorder in which the animals are exposed to a single traumatic event (electric foot-shock) after which fear memory is evaluated by re-exposing them to the context of the traumatic event and measuring the time spent motionless (freezing, a rodent fear-like response) the lack of TIP39 signaling did not cause a detectable change in fear memory one week after the shock. However, both mice lacking the peptide gene as well as mice with null mutation in the PTH2-R gene exhibited greater fear-like behavior than wild-type mice two weeks following the shock. Preliminary data suggests that PTH2-R signaling in the medial amygdalar region contributes to this phenomenon. Thus our data suggest that TIP39 signaling may normally limit the detrimental effects of environmental stress on emotional state. Dysfunctional responses to stress are widely thought to contribute to depression. We also found that TIP39 modulates acute pain sensitivity, acting primarily within the brain to affect the processing of painful sensory information. Some of the brain areas where TIP39 appears to modulate pain are also implicated in affective disorders. There is a significant association between chronic pain and depression. The extents to which pain affects mood and to which mood affects pain are not currently clear, nor is the extent to which shared vulnerability factors contribute to the development of both chronic pain and mood disorders. Because of TIP39s involvement in acute pain, the localization of TIP39 signaling to brain regions involved in affective dimensions of pain, its involvement is stress responses, and the significant societal burden of comorbid chronic pain and depression, we began investigating the involvement of TIP39 signaling in chronic pain, with the long-term goal of assessing its contribution to the relationships between pain and depression. Using a nerve injury as a model of neuropathic pain, we found that as compared to controls, mice lacking TIP39 signaling because of mutation in either the PTH2R or TIP39 genes developed less tactile and thermal hypersensitivity, and more rapidly returned to baseline sensory thresholds following the injury. Effects of inflammatory injury were similarly decreased in knockout mice. Blockade of α-2 adrenergic receptors increased the tactile and thermal sensitivity of apparently recovered knockout mice, returning it to levels of neuropathic controls. The locus coeruleus (LC), a brainstem nucleus, is the most likely source of the neuromodulator, norepinephrine, that could have this effect. Supporting this hypothesis, mice with LC area injection of lentivirus encoding a secreted PTH2R antagonist had a rapid, α-2 reversible, apparent recovery from neuropathic injury similar to the knockout mice. Ablation of LC area glutamatergic neurons led to local PTH2R-ir loss, and barley lectin (a transneuronal tracing reagent) was transferred from local glutamatergic neurons to GABA interneurons that surround the LC. These results suggest that TIP39 signaling modulates sensory thresholds via effects on glutamatergic transmission to brainstem noradrenergic neurons via GABAergic interneurons. The data suggest that TIP39 may normally inhibit release of hypoalgesic amounts of norepinephrine during chronic pain. A speculation on the physiological adaptiveness of TIP39s contribution to maintenance of central sensitization is that it enhances guarding behavior, thus contributing to healing. A next step in this line of investigation will be to evaluate the effects of TIP39 signaling on mood and anxiety related behavior in these chronic pain models. Because of the Sections long-term interest in neuromodulator influences on mood disorders we initiated a project aimed at increased understanding of the contributions of LC noradrenergic signaling to mood and anxiety related behaviors. Correlative observations suggest that LC function is involved in a variety of brain disorders but there is little direct evidence addressing its specific role(s). Recently developed reagents, such as transgenic mice that express Cre-recombinase in defined neuronal populations and viruses encoding receptors with Cre-dependent expression should make mechanistic studies feasible. During this review period we initiated this research direction using transgenic mice and recombinant viruses to map the major forebrain projections to the LC in mouse. One significant accomplishment was production of strong evidence for direct innervation of noradrenergic LC neurons by GABA neurons of the central amygdalar nucleus. Future studies will use this approach to examine the effects of changes in LC function on mood and anxiety related behaviors.

摘要：研究39个残基（TIP39）及其受体，甲状旁腺激素2（PTH2）受体的神经肽结核菌的生理功能一直是该实验室的重点。这些分子是几年前在这个实验室中发现的。在过去的项目中，我们绘制了TIP39和PTH2受体的神经解剖分布。 TIP39由3个离散的神经元组合成，在丘脑的尾部边界和1个在脑干中合成。 TIP39将神经元的合成项目投向了与情绪功能调节有关的几个大脑区域。这些区域包含PTH2受体的匹配分布，以及这些区域中的神经元向包含TIP39神经元的区域投影。因此，该系统的定位是协调和调节与精神障碍相关的功能。在此解剖学映射之后，实验室项目转向调查源自TIP39和PTH2R分布的假设。 下丘脑包含含有末端的PTH2RS和TIP39的密度相对较高。在过去的项目中，我们发现TIP39调节下丘脑旁脑室中神经元的激活，该核控制着多种神经内分泌功能，包括从肾上腺（啮齿动物中皮质酮）释放糖皮质激素胁迫激素。 TIP39通过作用于释放经典快速发射器谷氨酸的室核内神经元的末端来做到这一点。因此，TIP39调节神经内分泌细胞的兴奋性输入。我们还发现，在另一个下丘脑区域的TIP39信号传导，即型前核，有助于体温调节。具体而言，对冷暴露的适当稳态反应需要TIP39信号传导，而在适应小鼠的环境中维持正常基线温度则没有。这些研究导致了一个普通模型，即在特定高需求条件下，对于鲁棒和足够的兴奋性发射机释放，可能需要对某些谷氨酸能神经元的突触前PTH2RS作用。 在该项目的前几年，我们发现编码TIP39基因遗传缺失的小鼠（TIP39-KO）具有增加的焦虑样行为，这取决于测试条件产生的压力水平。在最小压力的条件下，TIP39的损失几乎没有影响，而在没有TIP39的压力动物下，与正常TIP39功能的小鼠相比，没有TIP39的焦虑样行为明显更大。我们还研究了TIP39在调节压力对认知功能的影响中的作用。在依赖记忆功能的行为测试中，由于配体或受体丧失或急性受体阻滞而缺乏TIP39信号传导的小鼠在依赖记忆功能的行为测试（物体识别和社会识别测试和Y迷宫中的自发交替）中表现出受损的性能），在新颖的条件下但是，当适应测试环境时没有。我们还发现TIP39信号传导调节了长期的情绪记忆。在创伤后应激障碍的小鼠模型中，动物暴露于单个创伤事件（电动脚击）之后，通过将它们重新暴露于创伤事件的背景下来评估恐惧记忆并测量所花费的时间一动不动的（冻结，类似啮齿动物的恐惧反应）缺乏TIP39信号传导并没有导致恐惧记忆发生后一周的恐惧记忆发生变化。然而，两只缺乏肽基因的小鼠和PTH2-R基因中无效突变的小鼠均表现出比野生型小鼠的恐惧样行为更大。初步数据表明，内侧杏仁核区域的PTH2-R信号传导有助于这种现象。因此，我们的数据表明，TIP39信号通常可能会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。 我们还发现，TIP39调节急性疼痛敏感性，主要作用在大脑内部，以影响疼痛的感觉信息的处理。 TIP39似乎调节疼痛的某些大脑区域也与情感障碍有关。慢性疼痛与抑郁之间存在显着关联。疼痛影响情绪的范围以及情绪影响疼痛的范围目前尚不清楚，共享脆弱性因素在多大程度上导致慢性疼痛和情绪障碍的发展。由于TIP39s参与急性疼痛，TIP39信号传导向涉及疼痛情感维度涉及的大脑区域的定位，其参与是压力反应，以及合并症的慢性疼痛和抑郁的重大社会负担慢性疼痛，其长期目标是评估其对疼痛与抑郁之间关系的贡献。 使用神经损伤作为神经性疼痛的模型，我们发现与对照组相比，由于PTH2R或TIP39基因突变而缺乏TIP39信号传导的小鼠的触觉和热过敏性较小，并且更快地返回到基线感觉阈值之后。受伤。敲除小鼠的炎症损伤的影响同样降低。 α-2肾上腺素能受体的阻断增加了明显恢复的基因敲除小鼠的触觉和热灵敏度，从而将其恢复到神经性控制的水平。脑干核基因座（LC）是可能具有这种作用的神经调节剂去甲肾上腺素的最可能来源。支持这一假设，用LC区域注射慢病毒的小鼠编码一个分泌的PTH2R拮抗剂具有快速，可逆的，明显的神经性损伤恢复，类似于敲除小鼠。 LC区域谷氨酸能神经元的消融导致局部PTH2R-IR损失，大麦凝集素（一种跨神经元跟踪试剂）从局部谷氨酸能神经元转移到围绕LC的GABA中神经元。这些结果表明，TIP39信号传导通过对谷氨酸能传播到脑干去甲肾上腺素能神经元的影响通过GABA能中间神经元调节感觉阈值。数据表明，TIP39通常可以抑制慢性疼痛期间的低粘量去甲肾上腺素的释放。关于TIP39对维持中央敏感性贡献的生理适应性的猜测是，它增强了保护行为，从而有助于康复。这一调查的下一步将是评估TIP39信号对这些慢性疼痛模型中情绪和焦虑相关行为的影响。 由于对神经调节剂对情绪障碍的影响的长期兴趣，我们启动了一个项目，旨在增加对LC甲肾上腺素能信号对情绪和焦虑相关行为的贡献的理解。相关观察结果表明，LC功能与多种脑部疾病有关，但几乎没有直接证据来解决其特定作用。最近开发的试剂，例如在定义的神经元种群中表达CRE成年酶的转基因小鼠和用CRE依赖性表达的受体编码受体的病毒，应该使机械研究可行。在此审查期间，我们使用转基因小鼠和重组病毒启动了该研究方向，以将主要前脑投影映射到小鼠中的LC。一个重要的成就是产生有力的证据，以直接通过中央杏仁核的GABA神经元直接支配去甲肾上腺素能神经元神经支配。未来的研究将使用这种方法来检查LC功能变化对情绪和焦虑相关行为的影响。