Chromatin Remodeling in the Prefrontal Cortex in Cocaine Addiction

描述（由申请人提供）：成瘾的一个标志是过度的药物寻求行为，据信这是由包括前额叶皮质在内的许多脑结构的病理变化介导的，涉及药物诱导的基因表达改变。染色质重塑或表观遗传调控是基因表达的关键决定因素，最近被牵连在药物诱导的神经可塑性。本项目将开发一个合作的努力是主要研究者（Kippin），其专业知识是行为神经科学，和共同主要研究者（Sun），其专业知识是表观遗传学，探索染色质重塑过程中产生的大鼠可卡因自我管理模型成瘾。具体而言，本研究基于可卡因自我给药（通过静脉导管）的大鼠模型，每日短期或长期给药，后一种情况导致可卡因摄入量的时间依赖性增加和随后的复发脆弱性，这与可卡因成瘾中观察到的模式相似。基于在通过长期接触可卡因自我施用产生的背内侧前额叶皮层中使用MeDIP-CHIP测定的DNA甲基化的高通量、全基因组分析的结果，本申请将验证感兴趣基因中的甲基化，确定那些基因表达的后果，（在mRNA和蛋白质水平上），确定可卡因暴露产生的表观遗传机制的变化，并确定可卡因戒断2个月后这些变化的持久性。该项目的长期目标是建立高通量DNA甲基化和其他技术的实用性，以识别成瘾中涉及的分子靶点，并建立我们实验室之间的合作，以绘制神经回路中染色质重塑（DNA甲基化和组蛋白修饰）的变化，介导成瘾中被破坏的动机和认知过程。这些研究将提供一个更详细的了解染色质重塑的作用，与成瘾过程相关的脑病理。 公共卫生相关性：基因表达的变化与成瘾过程中大脑结构的病理功能有着广泛的联系。本项目将确定染色质重塑的贡献，特别是DNA甲基化，前额叶皮层内的基因表达变化，在大鼠模型中产生的过量可卡因摄入。这些实验将建立一个框架，通过采用高通量分子技术结合疾病相关的行为模型，研究成瘾中染色质修饰水平的遗传功能的长期变化，以告知我们对成瘾相关脑病理学的理解。

DESCRIPTION (provided by applicant): A hallmark of addiction is excessive drug-seeking behavior which is believed to be mediated by pathological changes in a number of brain structures, including the prefrontal cortex, involving drug-induced alterations in gene expression. Chromatin remodeling or epigenetic regulation is a key determinant of gene expression that has recently been implicated in drug-induced neuroplasticity. The present project will develop a collaborative effort been the Principal Investigator (Kippin), whose expertise is in behavioral neuroscience, and the co-Principal Investigator (Sun), whose expertise is in epigenetics, to explore chromatin remodeling produced during a rat cocaine self-administration model of addiction. Specifically, this study is based on a rat model of cocaine self-administration (via a i.v. catheter) with either short or prolonged daily access with the latter condition leading to a time-dependent escalation of cocaine intake and subsequent relapse vulnerability which is similar to the pattern observed in cocaine addiction. Based on the results of a high-throughput, genome-wide analysis of DNA methylation using a MeDIP-CHIP assay in the dorsal medial prefrontal cortex produced by prolonged access to cocaine self- administration, the present application will verify methylation in genes of interest, determine the consequences for expression of those genes (at mRNA and protein levels), determine changes in the epigenetic machinery produced by cocaine exposure, and determine the enduring nature of these changes across 2 months of cocaine withdrawal. The long-term goals of this project are to establish the utility of high-throughput DNA methylation and other techniques to identify molecular targets involved in addiction as well as establish a collaboration between our laboratories to map changes in chromatin remodeling (both DNA methylation and histone modifications) in neural circuits mediating motivational and cognitive processes that are disrupted in addiction. These studies will provide a more detailed understanding of the role of chromatin remodeling to the brain pathology associated with the addiction process. PUBLIC HEALTH RELEVANCE: Changes in gene expression are widely implicated in the pathological function of brain structures during the addiction processes. The present project will determine the contribution of chromatin remodeling, specifically DNA methylation, to gene expression changes within the prefrontal cortex that are produced in a rat model of excessive cocaine intake. These experiments will establish a framework for studying the long-term changes in genetic function at the chromatin modification level in addiction through the employment of high-throughput molecular techniques combined with diseases relevant behavioral models in order to inform our understanding of addiction-related brain pathology.