Identifying genomic loci related to vulnerability to opioid addiction

接触阿片类药物的人中有8%-12%患上阿片类药物使用障碍(OUD)。开发更有效的产品 OUD的预防和治疗需要对基因组和表观遗传学机制有更好的了解 这是个体易受OUD轨迹不同阶段影响的基础(例如，首次使用、强迫症 使用，复发)。这项提案的总体目标是使用异种繁殖的大鼠模型(Spraogue-Dawley)来识别 涉及3种行为表型的新的下游基因和上游基因转录调节因子 与沿OUD轨迹的不同阶段相关联。通过比较表现为高水平和低水平的老鼠 在每个阶段，我们将能够识别基因表达的变化和它们的 在阿片成瘾的众多影响中，与阿片成瘾的易感性特别相关的监管 与上瘾无关的阿片类药物。在急性吗啡戒断过程中产生的快感缺失(即， 戒断诱导性快感缺乏症(WIA)将作为OUD最早阶段的一种成瘾表型。 在自愿吸食毒品之前。我们之前已经发现，WIA与 后续静脉注射的量度范围。吗啡自我给药(SA)比这些SA措施都是一种 又一个。对吗啡的经济需求和灭绝后的恢复将作为毒品的衡量标准 在广泛的吗啡SA后，强化效果和复发倾向分别为。要确定 ，我们将使用下一代测序(NGS)技术和 先进的生物信息学工具比较高表达大鼠的转录和表观基因组差异 与WIA(目标1)、需求(目标2)或恢复(目标3)的低水平相比。我们的表观基因组分析将绘制 染色体可及性基因座(使用ATAC-seq)和稳定染色质标记H3K4me3的基因座(使用芯片- SEQ)。我们将把这些数据集中的每一个都叠加到rna-seq数据上，以识别显示差异的基因。 高易感大鼠与低易感大鼠的激活以及这些转录调控因子的上游调控 效果。这些分析将集中在内侧前额叶皮质(MPFC)，这是中皮质边缘内的一个节点 在成瘾中起关键作用的系统。我们还将叠加从我们的研究中获得的表观基因组图 对表现为高VS的异质种(HS)大鼠的更大规模研究的基因分型数据 其他NIDA动物遗传学中低成瘾相关的行为表型(例如，药物摄入量、冲动) 联合体U01/P50项目。我们假设这些比较将产生一组下游基因 上游调控者与早期成瘾行为易感性的个体差异有关 一旦确定了它的严重性。我们进一步假设我们的转录和表观基因组数据 为从更大的基因组数据集中识别基因变异提供可行的路线图 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 制定更有效、个性化的方法来预防和治疗OUD的目标。

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.