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： 脑部炎症。 ARB 可逆转脑血管炎症，并限制全身施用细菌内毒素脂多糖 (LPS) 引起的外周和大脑先天免疫反应。 2009财年我们重点研究ARB的抗炎作用机制，选择啮齿类动物大脑靶区和人体循环靶细胞进行研究。 循环促炎细胞因子和 LPS 通过刺激特定靶点、脑血管内皮细胞、室旁核 (PVN) 和穹窿下器官 (SFO) 诱导大脑先天免疫反应。外周施用中枢作用的 ARB 可通过一氧化氮、前列腺素、核因子 kappa-B (NFkappaB) 激活和 LPS 分子识别等过程减少 LPS 诱导的 PVN 和 SFO 中多种炎症标志物的基因转录。此外，ARB 降低了许多大脑区域（包括皮质结构）的小胶质细胞激活。这表明ARBs在大脑中的抗炎作用是广泛的。 我们在先天免疫反应的调节中建立了 AT1 受体和血清素之间的联系。 ARB 通过阻止 LPS 诱导的犬尿氨酸途径上调来减少自由基的产生，犬尿氨酸途径是一种促进血清素代谢的促炎途径。 我们使用了基因删除（基因敲除，k.o.）小鼠模型。在 AT2 k.o.在雌性小鼠中，LPS 可以增强循环中的促炎细胞因子，并上调免疫反应和细胞凋亡程序。 在正常大鼠中，AT2 激动剂具有体内抗炎特性，包括降低犬尿氨酸途径活性。 我们的观察结果表明 AT2 受体是先天免疫反应的主要调节剂，AT2 受体激动剂是可能临床使用的新系列抗炎化合物的先导化合物。 使用 AT1 受体 k.o.在小鼠中，我们试图确定终生缺乏活性 AT1 受体是否会改变对免疫挑战的反应。我们正在利用原代小胶质细胞培养物研究 ARB 在脑部炎症期间减少小胶质细胞活化的过程。我们研究小脑颗粒细胞神经元培养物中神经元对炎症的反应过程。我们正在通过 AT1 受体基因的转染和沉默以及表型拯救研究来研究 ARB 保护人脑血管内皮细胞免受炎症影响的因素。 我们想要确定 ARB 对人类循环单核细胞、LPS 靶细胞以及大脑对外周炎症反应的主要因素的抗炎作用的程度和机制。我们之前发现，ARB 可以迅速减少未刺激的人单核细胞中 LPS 诱导的基因表达和促炎细胞因子的分泌。 2009 财年，我们重点关注导致这种效应的分子过程。我们确定多种机制导致了 ARB 在人类单核细胞中的抗炎作用，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受体γ (PPARγ) 的特异性拮抗剂可降低ARB 的作用，PPARγ 是一种下调促炎基因表达的转录因子。结论是，ARB 是多功能抗炎化合物，在人体细胞中具有双重 AT1 受体阻断和 PPARgamma 激动剂作用。我们的研究结果具有重要的转化意义，因为 ARB 在临床上是安全的，并且可以用于预防和治疗大脑炎症性疾病。 在寻找强效、安全、中枢作用的抗炎化合物的过程中，我们最近研究了米诺环素，一种据报道具有抗炎和神经保护作用的四环素抗生素。 我们发现米诺环素可预防 LPS 诱导的人类单核细胞炎症，增加 Akt 的磷酸化，Akt 是 LPS 炎症途径的负调节因子。磷酸肌醇 3 激酶 (PI3K) 的特异性抑制剂可降低米诺环素的作用，表明 PI3K-Akt 通路参与米诺环素的抗炎作用。 压力。 在啮齿动物模型中，ARB 限制了 HPA 轴刺激、交感神经激活和皮质苯二氮卓 1 受体表达的改变。 苯二氮卓-1 受体是γ-氨基丁酸 A (GABAA) 受体复合物的一部分，该复合物是大脑中的主要抑制系统。 2009 财年，我们发现 ARB 可以阻止啮齿类动物皮层苯二氮卓受体对束缚应激的反应。这些结果解释了 ARB 的抗焦虑作用。 PVN 中 AT1 受体基因转录增加是所研究的所有类型应激的共同特征，支持我们的假设，即 AT1 受体在应激期间参与 HPA 轴刺激。 对免疫挑战的炎症和应激反应密切相关。我们之前发现 ARB 可以降低肾上腺对 LPS 诱导的应激和炎症的反应。我们现在报道，ARB 通过涉及一氧化氮生成和 NFkappaB 激活的过程，降低了 LPS 诱导的垂体选择性促炎因子基因转录的上调。 我们发现了 AT2 受体在压力期间发挥作用的证据，以及大脑 AT1 和 AT2 受体之间的串扰的证据。 具有中枢 AT2 阻断作用的 AT2 受体阻断剂的外周给药可降低 HPA 轴基础活性和脑酪氨酸羟化酶转录。 此外，AT1受体选择性地表达于脊髓感觉通路的背根神经节；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 受体参与应激期间感觉信息的调节。 我们继续研究 HPA 轴对应激的反应机制以及 ARB 对皮质 GABAA 系统的调节。此外，我们还关注两个基本的下丘脑上结构：海马体和蓝斑。海马体调节 HPA 轴对压力的反应，也是糖皮质激素调节反馈的重要部位。该结构表达大量参与海马功能的 AT1 受体。 蓝斑是压力期间中枢交感神经激活的主要参与者。在隔离和冷抑制期间，ARB 可防止应激依赖性酪氨酸羟化酶（儿茶酚胺生产中的限速酶）的上调。进一步了解 ARB 调节 HPA 轴、酪氨酸羟化酶和 GABAA 系统的过程将阐明这些化合物的抗应激和抗焦虑作用的机制。我们使用激光显微切割技术来识别 PVN、海马和蓝斑内的选择性神经元群，并使用基因微阵列来识别 Ang II AT1 和 AT2 受体影响下的调节途径。 总之，我们阐明了ARB抗炎、抗应激和抗焦虑作用的一些作用方式，并进一步明确了AT2受体的作用。 我们的转化研究表明，ARB 可能被视为一类新型安全、多任务药物，用于治疗包括焦虑、抑郁和创伤后应激障碍 (PTSD) 在内的精神疾病。阐明其作用机制可能会导致开发具有治疗潜力的化合物。