GR-Mediated Epigenetic Regulation of the CRH Gene

GR 介导的 CRH 基因表观遗传调控

• 批准号: 7923718
• 负责人: Rosalie Marie Uht
• 金额: $ 36.6万
• 依托单位: UNIVERSITY OF NORTH TEXAS HLTH SCI CTR
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2014-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7923718
• 关键词: Adrenal Glands; Affect; Animals; Anorexia Nervosa; Arginine; Base of the Brain; Cell Line; Cells; Chromatin; Circadian Rhythms; Corticosterone; Corticotropin-Releasing Hormone; Cyclic AMP; Cyclic AMP-Responsive DNA-Binding Protein; Data; Disease; Down-Regulation; Drug Combinations; Drug Delivery Systems; Environment; Enzymes; Epigenetic Process; Face; Family member; Feedback; Fluoxetine; Functional disorder; Generations; Genes; Glucocorticoid Receptor; Glucocorticoids; Goals; Heterogeneous Nuclear RNA; Histone Acetylation; Histones; Homeostasis; Hormonal; Hour; Hypothalamic structure; Immunohistochemistry; In Vitro; Individual; Kinetics; Label; Lead; Life; Light; Link; Measures; Mediating; Mental Depression; Methylation; Metyrapone; Modeling; Molecular Analysis; Monitor; Nervous system structure; Neuraxis; Neurons; Nuclear Receptors; Pathogenesis; Pattern; Peptides; Pharmaceutical Preparations; Pharmacologic Substance; Physiological; Pituitary Gland; Plasma; Play; Post-Traumatic Stress Disorders; Prozac; Rattus; Regulation; Regulatory Element; Research Design; Role; Schools; Serum; Site; Societies; Steroids; Stress; System; Techniques; Testing; Time; United States; Work; base; biological adaptation to stress; chromatin immunoprecipitation; chromatin modification; design; drug mechanism; experience; genetic regulatory protein; histone modification; hypothalamic pituitary axis; hypothalamic-pituitary-adrenal axis; in vivo; infancy; lifetime risk; novel; nuclear receptor coactivator 1; paraventricular nucleus; parvocellular; promoter; public health relevance; research study; response; stressor; tool; trend

DESCRIPTION (provided by applicant): Nineteen million people a year in the United States experience depression. A potentially lethal disease, depression puts a strain on family members, leads to lost hours at school and work, is costly to treat, and places a substantial burden on society. In light of this, it is surprising that the pathogenesis of depression is still poorly understood. One feature of the illness that is clear - depression is highly correlated with an abnormal response to stress. The stress response is mediated by the hypothalamic-pituitary-adrenal (HPA) axis. Activity of the HPA axis is normally tightly regulated, in large part because the end products, glucocorticoids, are potent down- regulators of the system. In depression, neurons in the hypothalamus that synthesize and secrete the peptide that triggers the stress response, corticotropin-releasing hormone (CRH), are insensitive to glucocorticoid down-regulation. Because these neurons are the final common integrators of inputs from the central nervous system and the hormonal milieu, if they are abnormally responsive, the entire functioning of the axis is negatively affected. The experiments described in this proposal are designed to elucidate mechanisms by which glucocorticoids down-regulate expression of the CRH gene (crh). Aims 1 and 2 take advantage of a relatively new and powerful technique, chromatin immunoprecipitation (ChIP), and a relatively new neuronal cell line (IVB), which has many features of CRH cells in the hypothalamus. Aim 1 is designed to determine which arrays of co-regulatory proteins are required for down-regulation of crh expression. Aim 2 is designed to determine the role that chromatin modification enzymes and their epigenetic marks play in regulating crh. In Aim 3, the work will be taken into an in vivo setting. Data gained from Aims 1 and 2 will guide the in vivo work by narrowing the array of possible candidates to be chosen for analysis. Two in vivo settings will be studied. First, patterns of coregulators and histone modification enzymes will be assessed at the circadian peak and trough of corticosterone (Cort). These experiments will permit analysis of the effect physiological changes in Cort levels exert on coregulators and histone modification enzymes. Second, rats will be administered metyrapone at short time points, and the same parameters assessed as in the circadian studies. Taken together, the studies will permit molecular analysis of epigenetic mechanisms that regulate the stress response. This unique combination of approaches to the study of depression will produce a novel array of data, leading to a greater understanding of mechanisms of HPA regulation, and increasing our ability to identify novel drug targets for the treatment of depression. PUBLIC HEALTH RELEVANCE: Depression is a remarkably common illness that carries a lifetime risk of 20-25% - one in every five people will experience an episode of depression in the United States. A potentially lethal disease, depression puts strain on family members, leads to lost hours at school and work, is costly to treat, and places a substantial burden on society. Many cases are treatable with drugs such as fluoxetine (Prozac), but rarely is any single drug continually efficacious for a given individual. The current trend is to use a combination of drugs; however, many of these drugs' mechanisms of action are poorly understood. Optimizing this poly-pharmaceutical approach can be better accomplished by defining various steps in the pathogenesis of depression, which will lead to the identification of novel drug targets. One aspect of depression is clear - it is inexorably linked to a dysfunctional response to stress. The physiological system that mounts the stress response is the hypothalamic-pituitary-axis. Stressors are integrated in the hypothalamus, which sits at the base of the brain. These cells synthesize and secrete corticotropin-releasing hormone, or CRH. It is this peptide that triggers the stress response, and it is the cells that synthesize CRH that are abnormal. The proposed studies are designed to elucidate mechanisms by which the stress steroids, glucocorticoids, exert their usual, and profound, inhibitory effect on the CRH neurons. The studies take advantage of a powerful technique, chromatin immunoprecipitation, which is currently in its infancy as an investigatory tool of the nervous system. Additionally, the studies incorporate a relatively new cell line derived from the hypothalamus that has many features of CRH neurons. Data from the cell line will be used to develop mechanistic models of the stress response, which will be tested in vivo in the last set of proposed experiments.

描述（由申请人提供）：美国每年有100万人遭受抑郁症。一种潜在的致命疾病，抑郁症会给家庭成员带来压力，导致学校和工作的时间损失，对治疗的代价很高，并且给社会带来了重大负担。鉴于这种情况，令人惊讶的是，抑郁症的发病机理仍然很少了解。疾病的一个特征是明显的 - 抑郁与对压力的异常反应高度相关。应力反应是由下丘脑 - 垂体 - 肾上腺（HPA）轴介导的。 HPA轴的活性通常受到严格的调节，在很大程度上是因为最终产物，糖皮质激素是系统的有效下调节剂。在抑郁症中，下丘脑中的神经元合成并分泌触发压力反应的肽，皮质激素释放激素（CRH）对糖皮质激素下调不敏感。由于这些神经元是中枢神经系统和荷尔蒙环境的最终共同集成剂，如果它们异常响应敏感，则轴的整个功能会对轴的整个功能产生负面影响。该提案中描述的实验旨在阐明糖皮质激素下调CRH基因（CRH）的表达的机制。目标1和2利用了相对较新的功能技术，染色质免疫沉淀（CHIP）和相对较新的神经元细胞系（IVB），该细胞系（IVB）具有下丘脑中CRH细胞的许多特征。 AIM 1旨在确定下调CRH表达需要哪些共同调节蛋白的阵列。 AIM 2旨在确定染色质修饰酶及其表观遗传标记在调节CRH中的作用。在AIM 3中，工作将被带入体内环境。从目标1和2获得的数据将通过缩小选择要分析的可能的候选人来指导体内工作。将研究两个体内设置。首先，将在皮质酮（CORT）的昼夜峰和槽中评估组蛋白修饰酶的模式。这些实验将允许分析CORT水平对核心调节剂和组蛋白修饰酶的影响生理变化。其次，将在短时间点对大鼠进行Metyrapone施用，并评估与昼夜节律相同的参数。综上所述，研究将允许对调节压力反应的表观遗传机制进行分子分析。这种抑郁症研究方法的独特组合将产生一系列新的数据，从而使人们对HPA调节机制有了更大的了解，并提高了我们鉴定出鉴定抑郁症治疗的新型药物靶标的能力。公共卫生相关性：抑郁症是一种非常普遍的疾病，终身风险为20-25％ - 每五个人中有一个人会在美国遭受抑郁症。一种潜在的致命疾病，抑郁症会给家庭成员带来压力，导致学校和工作的时间损失，对治疗的代价很高，并且给社会带来了重大负担。许多病例可以用氟西汀（Prozac）等药物治疗，但对于给定个体而言，任何单一药物都很少有效。当前的趋势是结合使用药物。但是，这些药物的许多作用机制都对知识很少。通过定义抑郁症发病机理的各个步骤，可以更好地实现这种多药方法，从而可以更好地实现，这将导致鉴定新的药物靶标。抑郁症的一个方面很明显 - 它与对压力的功能障碍反应无关。安装压力反应的生理系统是下丘脑 - 垂体轴。压力源集成在坐在大脑底部的下丘脑中。这些细胞合成并分泌促肾上腺素释放激素或CRH。正是这种肽会触发压力反应，而细胞合成CRH异常。拟议的研究旨在阐明应激类固醇，糖皮质激素，对CRH神经元的通常而深刻的抑制作用。研究利用了一种强大的技术，染色质免疫沉淀，该技术目前仍处于神经系统的研究工具中。此外，这些研究结合了从下丘脑衍生出的相对较新的细胞系，具有CRH神经元的许多特征。来自细胞系的数据将用于开发应力响应的机械模型，该模型将在最后一组提出的实验中在体内进行测试。