Role Of Neuropeptides And Biogenic Amines In Stress and Brain Inflammation

神经肽和生物胺在压力和脑炎症中的作用

• 批准号: 7969333
• 负责人: JUAN M SAAVEDRA
• 金额: $ 123.84万
• 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/7969333
• 关键词: AGTR2 gene; Acute; Adrenal Glands; Agonist; Angiotensin II; Angiotensin II Receptor; Animal Model; Animals; Anti-Inflammatory Agents; Anti-inflammatory; Anxiety; Apoptotic; Area; Benzodiazepine Receptor; Benzodiazepines; Biogenic Amines; Biological Psychiatry; Blood Circulation; Brain; Brain Diseases; Butyric Acids; Catecholamines; Cell Culture Techniques; Cells; Chronic; Clinical; Complex; Development; Dinoprostone; Disease; Encephalitis; Endothelial Cells; Endotoxins; Enzymes; Equilibrium; Feedback; Female; Free Radicals; Gene Deletion; Gene Expression; Generations; Genes; Genetic Transcription; Glucocorticoids; Goals; Hippocampus (Brain); Hormonal; Human; Hypothalamic structure; Immune; Immune response; Inflammation; Inflammatory; Inflammatory Response; Knock-out; Kynurenine; Lasers; Lead; Life; Limbic System; Link; Lipopolysaccharides; Mental disorders; Metabolism; Microdissection; Microglia; Minocycline; Molecular; Mus; NF-kappa B; Nerve Degeneration; Neurodegenerative Disorders; Neurons; Neuropeptides; Nitric Oxide; Nuclear Receptors; Organ; PPAR gamma; Pathogenesis; Pathway interactions; Peripheral; Pharmaceutical Preparations; Phenotype; Phosphatidylinositols; Phosphorylation; Phosphotransferases; Pituitary Gland; Population; Post-Traumatic Stress Disorders; Prevention; Prevention approach; Process; Production; Property; Prostaglandins; Rattus; Reactive Oxygen Species; Receptor Gene; Regulation; Regulatory Pathway; Reporting; Research; Rodent; Rodent Model; Role; Sensory; Series; Serotonin; Site; Spinal Cord; Spinal Ganglia; Stimulus; Stress; Structure; Subfornical Organ; System; Techniques; Testing; Tetracyclines; Therapeutic; Time; Transcription factor genes; Transfection; Translational Research; Treatment Efficacy; Tyrosine 3-Monooxygenase; Up-Regulation; base; biological adaptation to stress; cerebrovascular; cytokine; depression; effective therapy; granule cell; hypothalamic-pituitary-adrenal axis; in vivo; inflammatory marker; inhibitor/antagonist; locus ceruleus structure; molecular recognition; monocyte; mouse model; multitask; novel; novel strategies; novel therapeutics; paraventricular nucleus; prevent; programs; receptor; response; response to injury; restraint; restraint stress; sciatic nerve; selective expression; serotonin receptor; transcription factor

Summary: Brain inflammation. ARBs reverse cerebrovascular inflammation and limit the peripheral and brain innate immune response resulting from systemic administration of the bacterial endotoxin lipopolysaccharide (LPS). In FY 2009 we focused on the mechanisms of the anti-inflammatory effects of ARBs, selecting rodent brain target areas and human circulating target cells for study. Circulating pro-inflammatory cytokines and LPS induce a brain innate immune response by stimulating specific target sites, cerebrovascular endothelial cells, the paraventricular nucleus (PVN) and the subfornical organ (SFO). Peripheral administration of a centrally acting ARB decreased the LPS-induced gene transcription of multiple inflammatory markers in the PVN and SFO by processes including nitric oxide, prostaglandins, the nuclear factor kappa-B (NFkappaB) activation, and LPS molecular recognition. Moreover, ARBs decreased microglial activation in many brain areas including cortical structures. This indicates that the anti-inflammatory effect of ARBs in the brain is widespread. We established a link between AT1 receptors and serotonin in the regulation of the innate immune response. ARBs reduce free radical generation by preventing the LPS-induced up-regulation of the kynurenine pathway, a pro-inflammatory pathway contributing to serotonin metabolism. We have used gene-deletion (gene knock-out, k.o.) mouse models. In AT2 k.o. female mice, LPS enhances pro-inflammatory cytokines in the circulation and up-regulates the immune response and apoptotic programs. In normal rats, an AT2 agonist has anti-inflammatory properties in vivo, including reduction of the kynurenine pathway activity. Our observations established AT2 receptors as major regulators of the innate immune response and AT2 receptor agonists as lead compounds for new series of anti-inflammatory compounds of possible clinical use. Using AT1 receptor k.o. mice, we are attempting to determine whether life-long absence of active AT1 receptors changes the response to immune challenge. We are studying the processes of ARB reduction of microglia activation during brain inflammation using primary microglial cultures. We study the processes of neuronal response to inflammation in neuronal cultures of cerebellar granule cells. We are investigating the factors involved in the ARB protection from inflammation in cultures of human cerebrovascular endothelial cells with transfection and silencing of the AT1 receptor gene and phenotype rescue studies. We want to determine the extent and mechanisms of anti-inflammatory effects of ARBs on human circulating monocytes, target cells for LPS and a major factor in the response of the brain to peripheral inflammation. We previously found that ARBs rapidly reduced the LPS-induced gene expression and secretion of pro-inflammatory cytokines in unstimulated human monocytes. In FY 2009 we focused on the molecular processes leading to this effect. We determined that multiple mechanisms were responsible for the anti-inflammatory effect of ARBs in human monocytes, including inhibition of LPS-induced reactive oxygen species, nitric oxide and prostaglandin E2 formation. The ARB effects are decreased by a specific antagonist of the nuclear receptor peroxisome proliferator-activated receptor gamma (PPARgamma), a transcription factor down regulating pro-inflammatory gene expression. The conclusion is that ARBs are multifunctional anti-inflammatory compounds with dual AT1 receptor blockade and PPARgamma agonist effects in human cells. Our findings are of translational importance, because ARBs are clinically safe and may be tested for the prevention and treatment of inflammatory conditions of the brain. In our search for powerful, safe, centrally-acting anti-inflammatory compounds, we recently studied minocycline, a tetracycline antibiotic reported to be anti-inflammatory and neuroprotective. We found that minocycline prevents LPS-induced inflammation in human monocytes, increasing phosphorylation of Akt, a negative regulator of LPS inflammatory pathways. A specific inhibitor of phosphoinositide-3-kinase (PI3K) reduces minocycline effects, indicating that the PI3K-Akt pathway is involved in the anti-inflammatory effect of minocycline. Stress. ARBs limited the HPA axis stimulation, sympathetic activation and the alterations in expression of cortical benzodiazepine-1 receptors during isolation in rodent models. The benzodiazepine-1 receptor is part of the gamma amino butyric acid A (GABAA) receptor complex, the major inhibitory system in the brain. During FY 2009, we found that ARBs prevent the cortical benzodiazepine receptor response to restraint stress in rodents. These results explain the anti-anxiety effects of ARBs. Increased AT1 receptor gene transcription in the PVN is a common feature of all types of stress studied, supporting our hypothesis that AT1 receptors participate in the HPA axis stimulation during stress. The inflammatory and stress responses to immune challenge are closely related. We had previously found that ARBs decrease the response to LPS-induced stress and inflammation in the adrenal gland. We now report that ARBs decrease the LPS-induced upregulation of selective pro-inflammatory factor gene transcription in the pituitary gland, through processes involving nitric oxide production and NFkappaB activation. We have found evidence of a role for AT2 receptors during stress, and of cross-talk between brain AT1 and AT2 receptors. Peripheral administration of an AT2 receptor blocker with central AT2 blocking effects decreases the HPA axis basal activity and brain tyrosine hydroxylase transcription. Moreover, AT1 receptors are selectively expressed in dorsal root ganglia, sensory pathways in the spinal cord; they are transported in the sciatic nerve, and are expressed in sensory organs. These results suggest that AT1 receptors participate in the regulation of sensory information during stress. We continue our research on the mechanisms of the HPA axis response to stress and on the regulation of the cortical GABAA system by ARBs. In addition, we focus on two fundamental supra-hypothalamic structures, the hippocampus and the locus coeruleus. The hippocampus regulates the HPA axis response to stress and an important site for glucocorticoid regulatory feedback. This structure expresses large numbers of AT1 receptors involved in hippocampal function. The locus coeruleus is a principal player in the central sympathetic activation during stress. During isolation and cold restraint ARBs prevent the stress-dependent up-regulation of tyrosine hydroxylase, the rate-limiting enzyme in catecholamine production. Further understanding of the processes involved in the regulation of the HPA axis, tyrosine hydroxylase and GABAA systems by ARBs will clarify the mechanisms of the anti-stress and anti-anxiety effects of these compounds. We are using laser microdissection techniques to identify selective neuronal populations within the PVN, hippocampus and locus coeruleus, and gene microarrays to identify regulatory pathways under the influence of Ang II AT1 and AT2 receptors. In conclusion, we clarified some of the modes of action of ARB anti-inflammatory, anti-stress and anti-anxiety effects, and further defined the role of AT2 receptors. Our translational research suggests that ARBs may be considered as a novel class of safe, multitasking medications for the treatment of psychiatric disorders including anxiety, depression and PTSD. Elucidation of their mechanisms of action may lead to the development of compounds of therapeutic potential.

概括： 大脑炎症。 ARB会反向脑血管炎症，并限制全身给药细菌内毒素脂多糖（LPS）导致的外周和脑固有免疫反应。在2009财年，我们专注于ARB的抗炎作用的机制，选择啮齿动物脑靶区域和人类循环靶细胞进行研究。 循环促炎性细胞因子和LPS通过刺激特定靶位点，脑血管内皮细胞，副脑膜核（PVN）和下型器官（SFO）来诱导大脑先天免疫反应。通过包括一氧化氮，前列腺素，核因子Kappa-B（NFKAPPAB）激活和LPS分子识别的过程，通过包括PVN和SFO的多种炎症标记的LPS诱导的多种炎症标记的基因转录降低了LPS诱导的多种炎症标记基因转录的外围施用。此外，ARB在包括皮质结构在内的许多大脑区域的小胶质细胞激活降低。这表明ARB在大脑中的抗炎作用很普遍。 在调节先天免疫反应中，我们建立了AT1受体与5-羟色胺之间的联系。 ARB通过防止LPS诱导的Kynurenine Pathway的上调来减少自由基的产生，Kynurenine Pathway是一种促炎性途径，导致了5-羟色胺代谢。 我们已经使用了基因删除（基因敲除，K.O。）小鼠模型。在AT2 K.O.雌性小鼠LPS在循环中增强了促炎性细胞因子，并上调了免疫反应和凋亡程序。 在正常大鼠中，AT2激动剂在体内具有抗炎特性，包括降低Kynurenine途径活性。 我们的观察结果确立了AT2受体作为先天免疫反应和AT2受体激动剂的主要调节剂，作为可能临床使用的新系列抗炎化合物的铅化合物。 使用AT1受体K.O.小鼠，我们试图确定活跃的AT1受体是否存在终生缺乏改变对免疫挑战的反应。我们正在研究使用原发性小胶质细胞培养物在脑部炎症过程中ARB减少小胶质细胞激活的过程。我们研究小脑颗粒细胞神经元培养的神经元反应的过程。我们正在研究ARB保护在人脑脑脑内皮细胞培养中涉及的因素，并通过转染和沉默的AT1受体基因和表型救援研究进行了沉默。 我们要确定ARB对人循环单核细胞，LPS的靶细胞的抗炎作用的程度和机制，以及大脑对周围炎症反应的主要因素。我们先前发现，ARB迅速降低了未刺激的人单核细胞中LPS诱导的基因表达和促炎性细胞因子的分泌。在2009财年，我们专注于导致这种影响的分子过程。我们确定了多种机制是ARB在人单核细胞中的抗炎作用的原因，包括抑制LPS诱导的活性氧，一氧化氮和前列腺素E2的形成。 核受体过氧化物酶体增殖物激活的受体伽马（Ppargamma）的特定拮抗剂降低了ARB效应，这是调节促炎基因表达的转录因子。结论是，ARB是多功能的抗炎化合物，在人类细胞中具有双重AT1受体阻滞和ppargamma激动剂作用。我们的发现具有转化的重要性，因为ARB在临床上是安全的，并且可以通过预防和治疗大脑的炎症状况进行测试。 在我们寻找强大，安全，中心作用的抗炎化合物时，我们最近研究了米诺环素，据报道是一种抗炎和神经保护性的四环素抗生素。 我们发现，米诺环素可防止LPS诱导的人单核细胞炎症，从而增加Akt的磷酸化，Akt是LPS炎症途径的负调节剂。磷酸肌醇3-激酶（PI3K）的特异性抑制剂可降低米诺环素效应，表明PI3K-AKT途径参与米诺环素的抗炎作用。 压力。 ARB限制了HPA轴刺激，交感神经激活以及在啮齿动物模型中分离过程中皮质苯二氮卓1受体表达的改变。 苯二氮卓1受体是伽马氨基丁酸A（GABAA）受体复合物的一部分，这是大脑中主要的抑制系统。在2009财年期间，我们发现ARB可以防止皮质苯二氮卓受体对啮齿动物的约束应激的反应。这些结果解释了ARB的抗焦虑作用。 PVN中AT1受体基因转录的增加是所研究的所有类型应力的共同特征，支持我们的假设，即AT1受体参与压力期间的HPA轴刺激。 对免疫挑战的炎症和压力反应密切相关。我们以前已经发现ARB降低了肾上腺对LPS诱导的应激和炎症的反应。现在，我们报告说，ARB通过涉及一氧化氮的产生和NFKAPPAB激活的过程，降低了LPS诱导的选择性促炎因子基因转录的上调。 我们发现了在压力过程中AT2受体以及大脑AT1和AT2受体之间的串扰的证据。 具有中央AT2阻断效应的AT2受体阻滞剂的外围给药可降低HPA轴的基础活性和脑酪氨酸羟化酶转录。 此外，AT1受体在背根神经节中选择性表达，脊髓中的感觉途径。它们在坐骨神经中运输，并在感觉器官中表达。这些结果表明，AT1受体参与压力期间的感觉信息的调节。 我们继续研究HPA轴对应激的响应的机理以及ARBS Cortical Gabaa系统的调节。此外，我们专注于两个基本的上丘脑结构，海马和层层。海马调节HPA轴对应激的响应，也是糖皮质激素调节反馈的重要部位。该结构表达了大量参与海马功能的AT1受体。 座位点是压力期间中央交感神经激活中的主要参与者。在隔离和冷约束期间，ARB可防止酪氨酸羟化酶的应力依赖性上调，酪氨酸羟化酶是儿茶酚胺生产中限速酶的限制酶。通过ARBS的调节，对HPA轴，酪氨酸羟化酶和GABAA系统的调节过程的进一步了解将阐明这些化合物的抗压力和抗焦虑作用的机制。我们正在使用激光显微解剖技术来识别PVN，海马和基因座凝固层以及基因微阵列中的选择性神经元种群，以在ANG II AT1和AT2受体的影响下鉴定调节途径。 总之，我们阐明了ARB抗炎，抗压力和抗焦虑作用的某些作用方式，并进一步定义了AT2受体的作用。 我们的翻译研究表明，ARB可以被视为一种新型的安全，多任务药物，用于治疗精神疾病，包括焦虑，抑郁症和PTSD。阐明其作用机理可能导致治疗潜力化合物的发展。