Chromatin Remodeling in the Prefrontal Cortex in Cocaine Addiction

描述(申请人提供)：上瘾的一个标志是过度的药物寻找行为，这种行为被认为是由包括前额叶皮质在内的一些大脑结构的病理变化所介导的，涉及药物诱导的基因表达变化。染色质重塑或表观遗传调控是基因表达的关键决定因素，最近被认为与药物诱导的神经可塑性有关。本项目将开发一个合作努力是首席调查员(Kippin)，他的专长是行为神经科学，和联合首席调查员(Sun)，他的专长是表观遗传学，以探索在大鼠可卡因自我给药成瘾模型期间产生的染色质重塑。具体地说，这项研究是基于可卡因自我给药的大鼠模型(通过静脉注射。无论是短时间或长时间的每日接触，后一种情况会导致可卡因摄入量随时间增加，随后易复发，这与在可卡因成瘾中观察到的模式相似。基于使用MeDIP芯片对长期使用可卡因而产生的额叶背侧内侧皮质DNA甲基化的高通量全基因组分析的结果，本申请将验证相关基因的甲基化，确定这些基因表达的后果(在mRNA和蛋白质水平)，确定因接触可卡因而产生的表观遗传机制的变化，并确定这些变化在两个月的可卡因戒断期间的持久性质。该项目的长期目标是建立高通量DNA甲基化和其他技术的效用，以确定与成瘾有关的分子靶点，并在我们的实验室之间建立合作，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。这些研究将提供更详细的了解染色质重塑对与成瘾过程相关的大脑病理的作用。 公共卫生相关性：基因表达的变化广泛涉及成瘾过程中大脑结构的病理功能。本项目将确定染色质重塑，特别是DNA甲基化，对在过量摄入可卡因的大鼠模型中产生的前额叶皮质基因表达变化的贡献。这些实验将通过高通量分子技术结合疾病相关的行为模型，建立一个研究成瘾过程中染色质修饰水平上的遗传功能长期变化的框架，以期了解成瘾相关的脑病理。

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.