Transgenerational Effects of Drug-exposure: Epigenetic and Behavioral Impact

描述（由申请人提供）：药物成瘾是一种精神障碍，其特征是从娱乐性药物使用过渡到强迫性药物使用，尽管有严重的负面后果，但仍持续存在。尽管有人试图戒烟，但恢复吸毒的愿望或需要可能持续数月或数年。随着时间的推移，成瘾的持续性表明，暴露于药物会导致大脑的长期适应，这可能涉及转录和遗传调控的改变。除了遗传因素外，表观遗传机制也可能在维持成瘾方面发挥作用，不仅在个体的一生中， 在他/她的后代。然而，尚未描述药物暴露对几代人的潜在影响。到目前为止，还没有进行全面的研究，以确定是否暴露于药物滥用的父母一代导致行为或分子表型在后代的改变。为了解决这个问题，我们将研究两种机制不同的药物（可卡因和吗啡）在三个近交系小鼠品系（C57 BL/6 J，DBA/2 J，A/J），以及一个多代系列的F1杂种的表型后果。除了研究跨代的行为表型，我们将表征RNA表达，DNA甲基化和翻译后组蛋白修饰作为可遗传表观遗传变化的分子特征和机制基础。这些研究将使我们能够确定（1）两种机制不同的药物滥用是否会导致 成瘾相关表型在治疗后通过多代传递，（2）这些表型是否由表观基因组的变化（DNA甲基化、翻译后组蛋白修饰或RNA）介导，以及（3）这些表型是否以印记或等位基因特异性方式根据暴露父母的性别而变化。这些实验将为未来的研究提供信息，旨在阐明滥用药物导致跨代表型的机制。 公共卫生相关性：许多精神疾病的遗传，如成瘾，在人口中是显而易见的。然而，尽管在全基因组关联研究上花费了数百万美元，但大多数成瘾风险的遗传差异仍未被发现。事实上，并非所有的遗传信息都存在于DNA序列中，而且DNA化学修饰形式的“表观遗传”信息可以从父母传递给后代，这一点现在才被认识到。技术可用于以高通量方式鉴定这些变体;然而，如果表观遗传学上遗传变异， 有助于成瘾。小鼠已被广泛用于行为药理学和遗传研究，以研究成瘾的潜在机制，因此它是一种易于处理的生物体，可用于检测表观遗传。 这些发现可能会彻底改变我们对药物滥用遗传风险的理解， 改变子孙后代的行为。

DESCRIPTION (provided by applicant): Drug addiction is a psychiatric disorder characterized by a transition from recreational to compulsive drug use that continues in spite of severe negative consequences. Despite attempts by individuals to quit, the desire or need to resume drug-taking can last for months or years. The persistence of addiction over time suggests that exposure to drugs results in long-term adaptations in the brain that likely involve alterations in transcription and genetic regulation. In addition to genetic factors, epigenetic mechanisms may also play a role in the maintenance of addictions not only throughout an individual's lifetime, but in his/her descendants. However, the potential impact of drug exposure across generations has not been characterized. To date, no comprehensive study has been undertaken to determine if exposure to drugs of abuse in the parental generation leads to alterations in behavioral or molecular phenotypes in subsequent generations. To address this question, we will examine the phenotypic consequences of two mechanistically different drugs (cocaine and morphine) in three inbred mouse strains (C57BL/6J, DBA/2J, A/J) as well as a multi-generation series of F1 hybrids. In addition to studying behavioral phenotypes across generations, we will characterize RNA expression, DNA methylation, and post-translational histone modifications as both the molecular signature and the mechanistic basis for heritable epigenetic changes. These studies will allow us to determine (1) whether any of 2 mechanistically different drugs of abuse results in transmission of addiction-related phenotypes through multiple generations after treatment, (2) whether these phenotypes are mediated by changes to the epigenome (DNA methylation, post-translational histone modifications, or RNAs), and (3) whether these phenotypes vary according to the sex of exposed parent in an imprinted or allele-specific manner. These experiments will inform future studies aimed at elucidating the mechanisms by which drugs of abuse lead to transgenerational phenotypes. PUBLIC HEALTH RELEVANCE: The inheritance of many psychiatric diseases, such as addiction, is evident in the population. However despite the millions of dollars spent on genome-wide association studies, the genetic variance in risk for most addictions has eluded discovery. The fact that not all inherited information is present in the DNA sequence and that "epigenetic" information in the form of chemical modifications of DNA can be passed from parent to offspring is just now being appreciated. Techniques are available to identify these variants in a high-throughput fashion; however it is critical to establish first if epigenetically inherited variation contributes to addiction. The mouse has been used extensively in both behavioral pharmacology as well as genetic studies to investigate mechanisms underlying addiction, thus it is a tractable organism with which to detect epigenetic inheritance. These discoveries could revolutionize our understanding of inherited risk for drug abuse and in doing so change behavior of future generations.