Identifying genomic loci related to vulnerability to opioid addiction

8-12%的人暴露于阿片类药物发展阿片类药物使用障碍（OUD）。开发更有效 OUD的预防和治疗需要更好地了解基因组和表观遗传机制 其构成个体对沿OUD轨迹沿着的不同阶段的脆弱性的基础（例如，初次使用，强迫性 使用、复发）。本提案的总体目标是使用远交大鼠模型（Sprague-Dawley）来鉴定 3种行为表型中新的下游基因和上游基因转录调控因子 与沿OUD轨迹的沿着不同阶段相关联。通过比较高水平和低水平的老鼠， 成瘾样行为在每个阶段，我们将能够确定基因表达的变化及其 调节特别与阿片类药物成瘾的易感性从众多的影响， 与成瘾无关的阿片类药物在急性吗啡戒断期间产生的快感缺失（即， 戒断诱导的快感缺失，WIA）将被用作OUD的最早期的成瘾表型，即， 在自愿吸毒之前。我们以前已经发现，WIA与一个 一系列措施，随后静脉吗啡自我管理（SA）比这些SA措施是一个 另对吗啡的经济需求和灭绝后的恢复将作为药物的措施 强化疗效和复发倾向，分别广泛吗啡SA后。以识别 对于与可移植性相关的基因组靶点，我们将使用下一代测序（NGS）技术， 先进的生物信息学工具，以比较表现出高表达的大鼠的转录组和表观基因组差异 相对于低水平的水影响评估（目标1）、需求（目标2）或恢复（目标3）。我们的表观基因组分析会 染色体可及性（使用ATAC-seq）和稳定染色质标记H3 K4 me 3（使用ChIP-seq）的基因座。 seq）。我们将把这些数据集叠加到RNA-seq数据上，以识别表现出差异的基因。 高敏感性大鼠与低敏感性大鼠中的激活，以及这些转录的上游调节因子， 方面的影响.这些分析将集中在内侧前额叶皮层（mPFC），一个节点内的mesocorticolimbic 在成瘾中起着关键作用的系统。我们还将覆盖从我们的研究中获得的表观基因组图谱， 根据来自异质性原种（HS）大鼠的更大研究的基因分型数据， 低成瘾相关行为表型（例如，药物摄入，冲动），在其他NIDA动物遗传学 联合体U 01/P50项目。我们假设这些比较将产生一组下游基因 以及与成瘾样行为早期易感性个体差异相关的上游调节因子 及其严重性一旦确定。我们进一步假设，我们的转录组和表观基因组数据将 提供一个可行的路线图，用于从与以下疾病相关的较大基因组数据集中识别遗传变异： OUD易感性的个体差异。因此，我们的研究有望产生新的基因组和分子， 目标是制定更有效的，个性化的方法来预防和治疗OUD。

Between 8-12% of people exposed to opioids develop opioid use disorder (OUD). Developing more effective preventions and treatments for OUD requires a better understanding of genomic and epigenetic mechanisms that underlie individual vulnerability to distinct stages along the OUD trajectory (e.g., initial use, compulsive use, relapse). The overall goal of this proposal is to use an outbred rat model (Sprague-Dawley) to identify novel downstream genes and upstream regulators of gene transcription involved in 3 behavioral phenotypes associated with distinct stages along the OUD trajectory. By comparing rats that show high versus low levels of addiction-like behavior at each stage, we will be able to identify changes in gene expression and their regulation associated specifically with susceptibility to opioid addiction from among the numerous effects of opioids that are unrelated to addiction. Anhedonia produced during withdrawal from acute morphine (i.e., withdrawal-induced anhedonia, WIA) will be used as an addiction phenotype of the earliest phase of OUD, i.e. prior to voluntary drug consumption. We have previously found that WIA is more strongly associated with a range of measures of subsequent i.v. morphine self-administration (SA) than these SA measures are with one another. Economic demand for morphine and reinstatement after extinction will serve as measures of drug reinforcement efficacy and propensity for relapse, respectively, after extensive morphine SA. To identify vulnerability-related genomic targets, we will use Next-Generation Sequencing (NGS) techniques and advanced bioinformatic tools to compare transcriptomic and epigenomic differences in rats exhibiting high versus low levels of WIA (Aim 1), demand (Aim 2) or reinstatement (Aim 3). Our epigenomic assays will map loci of chromosomal accessibility (using ATAC-seq) and of the stable chromatin mark H3K4me3 (using ChIP- seq). We will overlay each of these data sets onto RNA-seq data to identify genes showing differential activation in High- versus Low-Susceptibility rats, as well as upstream regulators of these transcriptional effects. These assays will focus on the medial prefrontal cortex (mPFC), a node within the mesocorticolimbic system that plays a pivotal role in addiction. We will also overlay epigenomic maps derived from our studies onto genotyping data derived from larger studies of Heterogeneous Stock (HS) rats manifesting High- versus Low addiction-related behavioral phenotypes (e.g., drug intake, impulsivity), in other NIDA Animal Genetics Consortium U01/P50 projects. We hypothesize that these comparisons will yield a set of downstream genes and upstream regulators associated with individual differences in early vulnerability to addiction-like behavior and its severity once established. We further hypothesize that our transcriptomic and epigenomic data will provide a viable roadmap for identifying genetic variants from larger genomic datasets associated with individual differences in OUD susceptibility. As such, our studies promise to yield novel genomic and molecular targets for developing more effective, individualized approaches for the prevention and treatment of OUD.