Cell Specificity of the Human Heroin Epigenome

项目摘要 近年来，阿片类药物滥用和过量在美国已上升到流行病的程度。只有有限 药物选择是目前可用的，这在很大程度上是由于令人惊讶的缺乏知识， 鸦片成瘾的病理生理机制最近的动物研究提供了强大的 重复药物暴露通过表观遗传学改变诱导基因表达变化的证据 与成瘾相关的行为异常有关的调节。然而，关于 人类成瘾者大脑中的表观遗传景观仍然有限，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脑特异性表观遗传标记的全面映射， 利用死后组织匀浆进行人类基因组分析。然而，大脑的细胞异质性排除了 从这些数据中获得细胞类型特异性表观遗传修饰的可靠注释。该项目的目标1将 利用我们新开发的分子策略来阐明神经亚型特异性表观基因组， 海洛因成瘾与前所未有的细节-在四个不同的群体的脑细胞-这将高度 增强识别成瘾相关表观遗传变异的细胞类型特异性特征的可能性。 我们最近在谷氨酸能投射神经元和抑制性GABA的表观遗传学研究 来自人类眶额叶皮层（OFC）的中间神经元表明，许多活动依赖基因（ADG） “准备”以神经元亚型特异性的方式被激活。ADG由经验驱动 突触活动（包括接触成瘾药物）和调节神经系统的各个方面， （包括突触可塑性）。值得注意的是，我们最近在匀浆OFC样品中的RNA-seq数据显示， 其中最显著的变化是ADG亚组的下调。这些结果符合 随着越来越多的文献表明前额叶腹侧的输出减少， 药物成瘾的大脑皮层我们假设ADGs的稳态表达和诱导（ADGs的表达和诱导）可能与ADGs的表达和诱导有关。 后者是由其表观遗传环境决定的）在海洛因成瘾者中以神经元亚型特异性 我们将在目标2中检验这一假设。考虑到ADG在突触可塑性中的重要性， 伴随着药物成瘾的发展和维持，在目标2中，我们将利用一个翻译的 动物模型，探讨细胞特异性功能的ADGs对海洛因自我给药行为的贡献。 总的来说，这一创新的研究路线将开发出独特的数据集， 研究社区，并将提供急需的资源，全基因组神经亚型特异性 海洛因滥用和正常人的染色质和转录组图谱。此外， 动物模型可以促进新的治疗干预的发展。

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.