System genetics of menthol and nicotine addiction

大鼠是成瘾行为研究中最常用的模式生物。我们建议 在这项工作中建立了一个创新的混合鼠多样性小组（HRDP）。人力资源发展方案的独特之处在于它整合了： 1)与混合人群相似的高水平遗传多样性; 2）控制药物的方法 暴露并系统地研究基因与环境和基因与药物的相互作用;和3）一种方法， 跨尺度整合"成瘾组"数据：来自遗传学、基因组学和其他分子数据， 成瘾相关风险这项工作将是朝着开发精确的实验资源迈出的一步 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获取的， 任何研究人员都可以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来识别控制尼古丁与薄荷醇提示的激励效应的序列变体。 大约25%的吸烟者更喜欢薄荷香烟。临床研究表明， 促进启动，增强依赖性，使戒烟更加困难。鉴于样本量大 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手段来定义和测试遗传和分子机制， 薄荷脑的成瘾作用我们开发了一种大鼠模型， （IVSA）与口服薄荷醇提示。我们发现，1）薄荷醇促进尼古丁IVSA的获得，2）大鼠 接受薄荷醇提示尼古丁的人表现出强烈的消光爆发，这是药物渴望的模型，3）这些 大鼠也表现出强烈的线索诱导的复发，即复发模型。我们还表明， 薄荷醇的凉爽感觉作为尼古丁奖励的条件提示， 治疗增加大脑尼古丁积累。关键的是，在这种U01机制的背景下，我们估计 这些性状的遗传力大于0.6。我们有三个目标：在目标1中，我们进行全基因组 HRDP的排序。我们将定义所有序列变异的基础遗传变异使用创新的 链接读取库和从头组装。在目标2中，我们用薄荷醇提示对尼古丁IVSA进行表型， 具有深度复制的两种性别的青春期HRDP动物。我们将用肉眼观察到的 Cue作为对照。将测量口服薄荷醇对脑尼古丁水平的影响。在目标3中，我们使用系统 遗传学方法来绘制和整合行为表型。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映射和测试候选基因与关键 辅因子（即，不同的线索）。最后，我们评估候选基因的翻译相关性， 通过与GWAS队列和人类成瘾的纵向报告进行比较来确定生物标志物。U01将 定义高影响变体和分子网络，并将提供一个预测性和可扩展的实验 将序列差异与人类尼古丁成瘾的关键方面联系起来。

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.