Trans-generational effects of nicotine self-administration

 描述（由申请人提供）：吸烟导致各种疾病的发展，从慢性肺和心脏病到多器官系统癌症。最近的证据表明，父亲吸烟与尼古丁依赖和后代儿童癌症发病率增加有关。这些发现表明，烟草烟雾能够影响后代的行为表型。在这里，我们描述了一种新的啮齿动物模型，以描绘一个遗传表型导致的自我管理的尼古丁。我们发现，与轭盐水对照组的后代相比，尼古丁经历过的公畜的雄性和雌性后代都增加了尼古丁自我给药。这些令人兴奋和挑衅性的结果与人类流行病学研究一致，并表明尼古丁经验丰富的公畜赋予其后代增加/增强尼古丁依赖的易感性。拟议的研究利用该动物模型进一步表征父亲尼古丁自我给药的跨代效应。目标1中概述的实验将评价自我给予尼古丁的雄性大鼠的后代（F1）和子代（F2）中尼古丁自我给药的获得和维持。还将在尼古丁父系和生理盐水父系F1和F2代中进行蔗糖自我给药的平行研究，以确定父系尼古丁自我给药的影响是否具有特定的尼古丁依赖性。虽然遗传因素对人类尼古丁依赖的风险有显著影响，但表观遗传影响对尼古丁相关遗传表型的潜在作用仍不清楚。表观遗传学是环境影响基因并与基因相互作用以影响行为的关键机制。表观遗传机制已被证明是药物诱导的行为可塑性的基础，通过协调大脑中基因网络的表达。因此，尼古丁可能影响尼古丁成瘾发展中涉及的遗传事件及其在后代中的遗传性的一种直接机制是表观遗传学。 然而，父亲尼古丁暴露影响后代吸烟行为的表观遗传机制尚未确定。因此，目标2的重点是确定潜在的分子靶点和表观遗传机制，与这种遗传表型。我们将使用微阵列和染色质免疫沉淀结合超高通量测序（ChIP-seq）来识别F1和F2尼古丁-sired大鼠的总RNA表达谱和髓核中DNA甲基化模式的全基因组变化，髓核是一个在尼古丁强化中起关键作用的大脑区域。这些研究的结果将使我们能够确定基因网络和表观遗传标记，这些基因网络和表观遗传标记调节对尼古丁强化的易感性增加的父系传递，从而为药物发现计划提供信息，这些计划旨在为慢性吸烟行为高风险的几代人开发新型戒烟药物。

 DESCRIPTION (provided by applicant): Tobacco smoking results in the development of variable illness ranging from chronic lung and heart disease to cancer of multiple organ systems. Recent evidence indicates that paternal smoking is associated with nicotine dependence and increased incidence of childhood cancer in offspring. These findings indicate that tobacco smoke is capable of affecting behavioral phenotypes in future generations. Here, we describe a novel rodent model developed in order to delineate a heritable phenotype resulting from the self-administration of nicotine. We found that both male and female offspring of nicotine-experienced sires had increased nicotine self- administration when compared to the offspring of yoked saline controls. These exciting and provocative results are consistent with human epidemiological studies and suggest that nicotine-experienced sires confer increased/enhanced susceptibility to nicotine dependence in their offspring. The proposed research utilizes this animal model to further characterize the trans-generational effects of paternal nicotine self-administration. The experiments outlined in Aim 1 will evaluate the acquisition and maintenance of nicotine self-administration in the offspring (F1) and grandoffspring (F2) of male rats that self-administered nicotine. Parallel studies of sucrose self-administration will also be conducted in nicotine-sired and saline-sired F1 and F2 generations in order to determine whether the effects of paternal nicotine self-administration are reinforcer-specific. While genetic factors contribute significantly to the risk of nicotine dependence in humans, the potential role of epigenetic influences on nicotine-associated heritable phenotypes remains unclear. Epigenetics is a key mechanism by which the environment can influence and interact with genes to influence behavior. Epigenetic mechanisms have been shown to underlie drug-induced behavioral plasticity by coordinating expression of gene networks in the brain. Thus, one direct mechanism by which nicotine may influence genetic events involved in the development of nicotine addiction as well as its heritability in future generations is epigenetics. However, the epigenetic mechanisms by which paternal nicotine exposure influences smoking behavior in subsequent generations have not been identified. Therefore, Aim 2 focuses on identifying potential molecular targets and epigenetic mechanisms that are associated with this heritable phenotype. We will use microarrays and chromatin immunoprecipitation coupled to ultra high-throughput sequencing (ChIP-seq) to identify genome-wide changes in total RNA expression profiles and DNA methylation patterns in the nucleus accumbens, a brain region that plays a critical role in nicotine reinforcement, of F1 and F2 nicotine-sired rats. Results from these studies will allow us to identify gene networks and epigenetic marks that regulate patrilineal transmission of increased susceptibility to nicotine reinforcement and thereby inform drug discovery programs aimed at developing novel smoking cessation medications in generations that are high risk for chronic smoking behavior.