Discovery of Addiction-Related Genes with Advanced Mouse Resources

 描述（由申请人提供）：我们的首要目标是发现成瘾行为倾向和发展的遗传和基因组机制。尽管作出了广泛的努力来遏制毒品的供应和使用，但吸毒成瘾仍然是全世界的一个重大社会和经济负担。吸毒成瘾的高遗传性，尤其是可卡因， 表明初次接触后发生物质使用障碍的倾向受到遗传影响。人类和动物研究都表明，行为特征，如新奇寻求和新奇偏好与发展物质使用障碍的倾向密切相关，但这种关系的生物学基础是未知的。我们建议通过利用小鼠遗传资源的最新进展来确定成瘾和易感行为的生物学机制，包括高精度的多样性远交（DO）小鼠种群，转基因小鼠的验证，通过RNA序列分析的基因表达定量，以及系统遗传学中的计算和统计方法。在目的1中，我们将通过在一个大型的DO小鼠组中进行数量性状位点（QTL）分析，确定诱发新奇相关性状和药物自我给药的遗传机制。其中最引人注目和最易处理的将在基因靶向小鼠模型中得到验证。静脉药物自我给药（IVSA）范式被认为是临床前研究中成瘾评估的金标准，它将能够量化成瘾的核心特征，包括强迫性药物使用、难以限制药物摄入和极高的服药动机。在目标2中，我们将量化基因表达遗传变异，定位表达QTL，并在未用药的DO小鼠亚组中使用RNAseq识别易感行为的遗传相关性，并通过广泛使用的信息资源传播这些结果。对未用药小鼠的基因表达分析能够将成瘾倾向的生物学底物与药物暴露的生物学后遗症分离开来。通过使用RNA测序，我们将能够在面对遗传多样性时量化同种型和等位基因变体。在目标3中，我们将利用易感行为特征作为参考，解决将药物初治个体基因表达的遗传变异与药物自我给药行为的遗传变异相关联的基本问题。这将通过使用多元统计方法来完成，我们称之为“参考性状遗传学”。该策略利用共同的表型集合来关联两组独立小鼠之间的不同和不相容的测量。在成瘾研究的背景下，这种技术的发展将把远系种群的应用扩展到健康和疾病的广泛应用。每个目标将独立地提供成瘾生物学家感兴趣的基础研究结果和资源，包括基因表达QTL，成瘾相关的遗传位点和成瘾相关行为的表达相关性。目标之间的协同作用将揭示网络从多态性到成瘾相关行为。

 DESCRIPTION (provided by applicant): Our overarching goal is to discover the genetic and genomic mechanisms underlying behavioral predisposition and development of addiction. Addiction remains a substantial worldwide social and economic burden despite extensive efforts to curb drug availability and use. The high heritability of drug addiction, especially for cocaine, indicates that the propensity to develop a substance use disorder after initial exposure is genetically influenced. Both human and animal studies indicate that behavioral traits such as novelty seeking and novelty preference are strongly correlated with the propensity to develop a substance use disorder, but the biological basis of this relationship is unknown. We propose to identify biological mechanisms of addiction and predisposing behavior by harnessing recent advances in mouse genetic resources, including the high-precision Diversity Outbred (DO) mouse population, validation in genetically modified mice, gene expression quantitation through RNA sequence analysis, and computational and statistical methods in systems genetics. In Aim 1 we will identify genetic mechanisms underlying predisposing novelty-related traits and drug self-administration through quantitative trait locus (QTL) analysis in a large set of DO mice. The most compelling and tractable of these will be validated in gene targeted mouse models. The intravenous drug-self administration (IVSA) paradigm, considered the gold standard for the assessment of addiction in preclinical research will enable quantification of the core features of addiction including compulsive drug use, difficulty limiting drug intake, and an extremely high motivation to take the drug. In Aim 2 we will quantify gene expression genetic variation, map expression QTLs and identify genetic correlates of predisposing behavior using RNAseq in a drug-naïve subset of DO mice, and disseminate these results through widely used informatics resources. Gene expression analysis in drug-naïve mice enables separation of the biological substrates of predisposition to addiction from the biological sequelae of drug exposure. By using RNA sequencing, we will be able to quantify isoforms and allelic variants in the face of genetic diversity. In Aim 3, we will address the fundamental problem of relating genetic variation in gene expression in drug-naïve individuals to genetic variation in drug self-administration behavior by utilizing predisposing behavioral traits as a reference. This will be accomplished through the use of multivariate statistical methods in an approach we term "reference trait genetics". This strategy makes use of a common collection of phenotypes to relate disparate and incompatible measures across two independent sets of mice. Development of this technique in the context of addiction research will extend the application of outbred populations to a wide range of applications in health and disease. Each aim will independently deliver basic research results and resources of interest to addiction biologists, including gene expression QTLs, addiction related genetic loci, and expression correlates of addiction related behavior. Synergy among the aims will reveal networks from polymorphism to addiction related behavior.