System genetics of menthol and nicotine addiction

大鼠是成瘾行为研究中最常用的模型生物。我们建议 在这项工作中，建立了一个创新的杂交鼠多样性小组(HRDP)。人力资源发展计划的独特之处在于它综合了： 1)类似于混合人类种群的高度遗传多样性；2)一种控制毒品的方法 暴露，并系统地研究基因与环境和基因与药物的相互作用；以及3)一种 从遗传学、基因组学和其他分子数据与KEY整合跨规模的“专有”数据 与上瘾相关的风险。这项工作将是开发精确度实验资源的一步。 医药。HRDP由91个高度多样化的大鼠基因组组成，这些基因组都是开放访问的，可以使用 由任何研究人员在不同的环境或不同的治疗下研究成瘾的各个方面。我们 将使用HRDP来识别通过薄荷醇线索控制尼古丁激励效应的序列变体。 大约25%的吸烟者更喜欢薄荷醇香烟。临床研究表明，薄荷脑 促进入门，增强依赖性，并使戒烟变得更加困难。考虑到样本量很大 在人类研究中需要识别与药物成瘾相关的关键序列变异，我们认为 动物模型提供了一种有效的方法来定义和测试基因和分子机制 薄荷醇的成瘾作用。我们建立了尼古丁静脉注射的大鼠模型。自治 (IVSA)，带有口服薄荷醇提示。我们发现1)薄荷醇促进了尼古丁的习得，2)大鼠 那些收到尼古丁薄荷脑提示的人表现出强烈的消退爆发，这是药物渴求的典范，以及3)这些 大鼠也表现出强烈的线索诱导的恢复，这是一种复发的模型。我们还展示了 薄荷醇的降温感觉起到了尼古丁奖励的条件性提示作用，而口服薄荷醇 治疗会增加大脑中尼古丁的积聚。关键的是，在这个U01机制的背景下，我们估计 这些性状的遗传力均大于0.6。我们有三个目标：在目标1中，我们进行全基因组 对HRDP进行测序。我们将使用创新的方法定义所有作为可遗传变异基础的序列变体 链接-读取库和从头开始的程序集。在目标2中，我们对尼古丁IVSA和薄荷醇线索进行了表型分析 青春期HRDP动物，雌雄不限，可深度复制。我们将通过视觉识别尼古丁IVSA的表型 作为一种控制提示。将测量口服薄荷脑对大脑尼古丁水平的影响。在《目标3》中，我们使用了 遗传学方法来定位和整合行为表型。正向(QTL)和反向(Phewas) 将使用遗传方法。我们将使用新的线性混合模型来定位和测试候选基因和关键字 辅因(即，不同的线索)。最后，我们评估了候选基因和候选基因的翻译相关性 生物标记物通过与GWA队列和人类成瘾的纵向报告进行比较。这款U01将 定义高影响的变体和分子网络，并将提供一个可预测和可扩展的实验 将序列差异与人类尼古丁成瘾的关键方面联系起来的框架。

The rat is the most commonly used model organism for behavioral studies of addiction. We propose to establish an innovative hybrid rat diversity panel (HRDP) in this work. The HRDP is unique in that it integrates: 1) a high level of genetic diversity similar to that of admixed human populations; 2) a way to control drug exposures and to systematically study gene-by-environment and gene-by-drug interactions; and 3) a way to integrate "addictome" data across scale: from genetics, genomics, and other molecular data together with key addiction related risks. This work will be a step toward developing experimental resources for precision medicine. The HRDP consists of 91 highly diverse genomes of rats that are all open access and can be used by any investigators to study facet of addiction and in different environments or under different treatments. We will use the HRDP to identify sequence variants that control motivational effects of nicotine with a menthol cue. Approximately 25% of smokers prefer mentholated cigarettes. Clinical studies have shown that menthol facilitates initiation, enhances dependence and makes quitting more difficult. Given the large sample size needed in human studies to identify key sequence variants associated with drug addiction, we argue that animal models provide an efficient means to define and test genetic and molecular mechanisms that contribute to the addiction-enhancing effects of menthol. We developed a rat model of nicotine i.v. self-administration (IVSA) with an oral menthol cue. We found that 1) menthol facilitates the acquisition of nicotine IVSA, 2) rats that receive the menthol cue for nicotine show a strong extinction burst, a model for drug craving, and 3) these rats also demonstrate a strong cue-induced reinstatement, a model of relapse. We also showed that the cooling sensation of menthol functions as a conditioned cue for nicotine reward, and that oral menthol treatment increases brain nicotine accumulation. Critically, in the context of this U01 mechanism, we estimate that heritability of these traits are greater than 0.6. We have three aims: In Aim 1 we conduct whole genome sequencing of the HRDP. We will define all sequence variants that underlie heritable variation using innovative linked-read libraries and de novo assemblies. In Aim 2 we phenotype nicotine IVSA with a menthol cue in adolescent HRDP animals of both sexes with deep replication. We will phenotype nicotine IVSA with a visual cue as a control. Effects of oral menthol on brain nicotine level will be measured. In Aim 3 we use systems genetics methods to map and integrated behavioral phenotypes. Both forward (QTL) and reverse (PheWAS) genetic methods will be used. We will use new linear mixed models to map and test candidate genes with key cofactors (i.e., different cues). Finally, we evaluate the translational relevance of candidate genes and biomarkers by comparison to GWAS cohorts and longitudinal reports of addiction in humans. This U01 will define high impact variants and molecular networks, and will provide a predictive and expandable experimental framework to link sequence differences to critical aspects of human nicotine addiction.