Novel Role for Sirtuin Signaling Mechanisms and Downstream Targets in Depression

描述（由申请人提供）：表观遗传因素可能在揭示包括抑郁症和药物成瘾在内的几种神经精神疾病发病机制的分子机制中发挥关键作用。基因似乎只能解释导致这些疾病的部分风险因素。美国国立卫生研究院独立之路奖（K99/R00）将极大地促进候选人的能力，开始他的职业生涯作为一个独立的科学家，使他能够研究潜在的基因-环境相互作用在主要情绪障碍的发病观察到的表观遗传机制。在纽约西奈山医学院神经科学系主任、弗里德曼脑研究所主任Eric Nestler博士的主要指导下，独立之路奖将为候选人提供机会，扩展和发展他在下一代测序技术和细胞类型特异性信号分析方面的培训和专业知识。该奖项将促进候选人的长期职业目标：(1)确定环境如何与基因相互作用，并确定经验赋予基因表达持久变化的机制，以及(2)发现新的易感性（或弹性）基因，以了解它们如何影响行为。尽管抑郁症的流行及其相当大的影响，关于其病理生理学的知识是基本的。因此，迫切需要发现促进抑郁症发展的新的信号通路，以便获得更好的诊断测试、治疗和预防措施。本研究项目的目的是评估SIRT1及其下游靶点作为神经精神疾病治疗的潜在新候选物的作用，方法是在对照和社交失败应激小鼠的伏隔核（NAc）组织中进行染色质免疫沉淀和全基因组分析（ChIP-seq）。我们实验室的初步数据显示，慢性社会失败压力是抑郁症和其他压力相关疾病的一种行为学验证模型，它调节NAc中的SIRT1水平，是一种足以增加压力敏感性的促抑郁药。SIRT1蛋白是NAD+依赖性去乙酰化酶和adp -核糖基转移酶家族的创始成员，称为sirtuins。在这项资助中，我们提议测试SIRT1的调节构成抗抑郁药的一个新的候选治疗靶点的假设。在该资助的指导k期（Specific Aim 1和Specific Aim 2），我们将使用药理学和遗传学工具直接确定sirtuins在调节抑郁和焦虑样行为中的作用。首先，我们将通过直接在nac内注射药物抑制剂（sirtinol）或其他药物来抑制或增加sirtuins的活性

DESCRIPTION (provided by applicant): Epigenetic factors may play a key role in unraveling the molecular mechanisms underlying the pathogenesis of several neuropsychiatric disorders, including depression and drug addiction. Genes appear to explain only part of the risk factor for developing these disorders. The NIH Pathway to Independence Award (K99/R00) will significantly facilitate the candidate's ability to begin his career as an independent scientist, allowing him to study the epigenetic mechanisms underlying the gene-environment interactions observed in the onset of major mood disorders. Under the primary mentorship of Dr. Eric Nestler, Chairman of the Department of Neuroscience, and Director of the Friedman Brain Institute, at Mount Sinai School of Medicine in New York, the Pathway to Independence Awards would provide the candidate the opportunity to extend and develop his training and expertise in next generation sequencing technologies and cell type specific signaling analysis. The Award would advance the candidate's long term career objectives to: (1) determine how the environment interacts with genes and identify mechanisms by which experience confers enduring changes in gene expression, and (2) discover novel susceptibility (or resilience) genes to understand how they influence behavior. Despite the prevalence of depression and its considerable impact, knowledge about its pathophysiology is rudimentary. Thus, there is an urgent need to discover novel signaling pathways contributing to the development of depression so that better diagnostic tests, treatments, and preventive measures can be attained. The objectives of this program of research are to evaluate the role of SIRT1 and its downstream targets as potential new candidates for the treatment of neuropsychiatric disorders by performing chromatin immunoprecipitation followed by genome-wide profiling (ChIP-seq) in nucleus accumbens (NAc) tissue from control and socially defeated stressed mice. Preliminary data from our lab show that chronic social defeat stress, an ethologically validated model of depression and other stress-related disorders, modulates SIRT1 levels in the NAc and is a pro-depressant sufficient to increase stress sensitivity. The SIRT1 protein is the founding member of a family of NAD+-dependent deacetylases and ADP-ribosyltransferases, termed sirtuins. In this grant we propose to test the hypothesis that modulation of SIRT1 constitutes a novel candidate therapeutic target for antidepressants. In the mentored K-phase of this grant (Specific Aim 1 and Specific Aim 2) we will directly determine the role of sirtuins in regulating depressive- and anxiety-like behaviors using pharmacological and genetic tools. First, we will inhibit or increase the activity of sirtuins by direct intra-NAc infusion of a pharmacological inhibitior (sirtinol) or activator (resveratrol) to assess the effects of sirtuins on the development of stress-induced depressive and anxiety-like behaviors. Next, we will specifically target SIRT1 using a genetic approach to overexpress HSV-Cre viral vectors in the NAc of floxed SIRT1 (SIRT1flx) mice to knock-down SIRT1 levels, or to increase SIRT1 levels by overexpressing SIRT1 using HSV-SIRT1 vectors in the NAc. In Specific Aim 2 we also will identify transcriptional targets of SIRT1 in the NAc regulated by social defeat and antidepressants in susceptible and resilient mice by performing ChIP-Seq for SIRT1 in addition to markers of gene activation and repression. In the independent phase (R00), Specific Aim 3, will characterize the effects of social defeat on sirtuin signaling in a cell type specific manner in the NAc using drd1-GFP and drd2-GFP transgenic mice, allowing for the identification of striatonigral and striatopallidal medium spiny neurons (MSNs). In summary, the research proposed in this Pathway to Independence Award will prepare the candidate to develop a fully independent research program capable of integrating a wide range of molecular and behavioral approaches in a technically advanced and high impact manner, including: (i) lines of genetically engineered mice to target cell type specific regulation of sirtuin signaling after exposure to chronic stress, (ii) the ability to isolate chromatin from bain tissue, (iii) ChIP followed by genome-wide profiling, (iv) a rodent model of depression with high validity, and (v) automated behavioral assays measuring many depression- and anxiety-like behavioral responses. .