Cell Specificity of the Human Heroin Epigenome

项目摘要 近年来，阿片类药物滥用和过量用药在美国已经上升到流行的比例。仅限 药物选择目前是可用的，这在很大程度上是因为令人惊讶地缺乏对 阿片成瘾的病理生理机制。最近的动物研究提供了强有力的证据 有证据表明，反复接触毒品会通过表观遗传学改变而导致基因表达的变化 与成瘾相关的行为异常有关的监管。但是，有关 人类成瘾者大脑中的表观遗传图景仍然有限，并且对成瘾者的发展至关重要 临床有效的治疗方法。 最近的研究已经实现了大脑特定表观遗传标记的全面图谱 利用死后组织匀浆提取人类基因组。然而，大脑细胞的异质性排除了 从这些数据中可靠地诠释了特定细胞类型的表观遗传修饰。这个项目的第一个目标是 利用我们新开发的分子策略来阐明神经亚型特定的表观基因组 海洛因成瘾具有前所未有的细节--在四种不同的脑细胞中--这将极大地 提高识别与成瘾相关的表观遗传变异的特定细胞类型特征的可能性。 我们最近对谷氨酸能投射神经元和抑制性GABA的表观遗传学研究 人类眼眶额叶皮质(OFC)的中间神经元提示许多活性依赖基因(ADGs)。 正准备以神经元亚型特有的方式被激活。ADG是由经验驱动的 突触活动(包括接触成瘾药物)和调节神经系统的不同方面， (包括突触可塑性)。值得注意的是，我们最近在匀浆OFC样本中的rna-seq数据显示 最重大的变化之一是下调了部分助理总干事的规定。这些结果是一致的 随着越来越多的文献暗示前额叶腹侧的输出减少 大脑皮层与药物成瘾。我们假设ADGs的稳态表达和诱导性( 后者是由他们的表观遗传环境决定的)在海洛因成瘾者中改变是神经元亚型特异性的 我们将在目标2中验证这一假设。考虑到ADGs在突触可塑性中的重要性 这伴随着药物成瘾的发展和维持，在目标2中，我们将使用翻译的 建立动物模型，探讨ADGs在海洛因自我给药行为中的细胞特异性功能贡献。 总体而言，这一创新的研究领域将开发独特的数据集，供 并将为全基因组神经亚型特异性研究提供迫切需要的资源 海洛因滥用和正常受试者的染色质和转录组图谱。此外，《金字塔》中的机理研究 动物模型可以促进新的治疗干预措施的发展。

Project Summary Opiate abuse and overdose have risen to epidemic proportions in the USA in recent years. Only limited medication options are currently available, which is in large part due to the surprising lack of knowledge about the pathophysiologic mechanisms that underlie opiate addiction. Recent animal studies have provided robust evidence that repeated drug exposure induces changes in gene expression through alterations in epigenetic regulation that are linked to addiction-related behavioral abnormalities. However, information about the epigenetic landscape in the brains of human addicts remains limited and is critical for the development of clinically effective treatments. Recent studies have achieved a comprehensive mapping of brain-specific epigenetic marks in the human genome using homogenate postmortem tissue. However, cellular heterogeneity of the brain precludes a reliable annotation of cell-type-specific epigenetic modifications from these data. Aim1 of this project will leverage our newly developed molecular strategies to illuminate the neural subtype-specific epigenome of heroin addiction with unprecedented detail—in four different populations of brain cells—which will highly enhance the likelihood of identifying cell-type-specific signatures of addiction-associated epigenetic variations. Our recent epigenetic studies in glutamatergic (Glu) projection neurons and inhibitory GABA interneurons from the human orbital frontal cortex (OFC) suggest that many activity-dependent genes (ADGs) are “poised” to be activated in a neuron-subtype-specific manner. ADGs are activated by experience-driven synaptic activity (including exposure to addictive drugs) and regulate diverse aspects of the nervous system, (including synaptic plasticity). Notably, our recent RNA-seq data in homogenate OFC samples showed that among the most significant changes is the downregulation of a subset of the ADGs. These results are in line with the growing body of literature that implicates diminished output from the ventral aspects of the prefrontal cortex in drug addiction. We hypothesize that the steady-state expression and inducibility of the ADGs (the latter is determined by their epigenetic milieu) are altered in heroin addicts in a neuron-subtype-specific manner, and we will test this hypothesis in Aim 2. Considering the importance of ADGs in synaptic plasticity that accompanies the development and maintenance of drug addiction, in Aim 2 we will utilize a translational animal model to explore the cell-specific functional contribution of ADGs to heroin self-administration behavior. Overall, this innovative line of research will develop unique datasets that will be available to the research community and will provide an urgently needed resource for genome-wide neural subtype-specific chromatin and transcriptome maps in heroin abuse and normal subjects. Moreover, the mechanistic studies in animal models can promote the development of novel therapeutic interventions.