Genetic modifiers of Chrna5 deletion in mice: role in nicotine behaviors modulated by the medial habenula-IPN pathway

小鼠 Chrna5 缺失的遗传修饰剂：在内侧缰核-IPN 通路调节尼古丁行为中的作用

• 批准号: 10308102
• 负责人: RICHARD A RADCLIFFE
• 金额: $ 60.64万
• 依托单位: UNIVERSITY OF COLORADO
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-04-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10308102
• 关键词: Alleles; Animals; Behavior; Biological; Cells; Chromosomes; Code; Congenic Mice; Congenic Strain; Consomic Strain; Critical Pathways; Data; Development; Drug usage; Future; Gene Expression; Gene Expression Profile; Gene-Modified; Generations; Genes; Genetic; Genomics; Goals; Habenula; Human; Individual; Intake; Lead; Maps; Medial; Messenger RNA; Methods; Molecular; Mus; Mutant Strains Mice; Names; Neural Pathways; Neurons; Nicotine; Nicotine Dependence; Nicotine Withdrawal; Nicotinic Receptors; Oral; Pathway interactions; Pharmaceutical Preparations; Pharmacotherapy; Phenotype; Physiological; Play; Population; Procedures; Process; RNA; Resolution; Rewards; RiboTag; Risk; Rodent; Role; Self Administration; Smoker; Testing; Variant; Withdrawal; base; behavior test; behavioral response; cell type; chromosomal location; conditioned place preference; congenic breeding; effective therapy; experimental study; follow-up; genetic approach; interest; interpeduncular nucleus; loss of function; new therapeutic target; novel; novel therapeutics; null mutation; response; restoration; smoking cessation; success; transcriptome sequencing

PROJECT SUMMARY/ABSTRACT Less than 1 in 10 individuals who attempt to quit smoking remain abstinent for 1 year. This poor quit rate is driven, in part, by the fact that currently available drugs used to aid in smoking cessation are only moderately effective, at best. Thus, there is a great need to develop novel drugs that are more effective for smoking cessation. It is the goal of this project to use a novel genetic strategy to identify new biological targets for the potential development of novel smoking cessation drugs. The genetic strategy is based upon identifying modifier genes that alter nicotine responses in mice that have a null mutation in Chrna5, the gene that codes for the nicotinic receptor α5 subunit. In effect, modifier genes are genes that contribute to physiological and/or molecular processes that are important for the behavior of interest but that generally go undetected in the absence of a perturbation in the gene that they modify. Because variants in Chrna5 alter risk for nicotine dependence in humans and studies in rodents clearly demonstrate that Chrna5 is critical for many nicotine- related behaviors, we believe that identifying genes that modify the effect of Chrna5 deletion on nicotine behaviors will uncover new genes relevant to nicotine dependence that may serve as novel targets for novel smoking cessation pharmacotherapies. Importantly, the behaviors that we plan to screen for modifiers are not only dependent upon Chrna5, but also dependent uponthe medial habenula-IPN pathway, a neural pathway that is thought to play a critical role in nicotine dependence. To identify genetic modifiers of the effect of Chrna5 deletion on nicotine behaviors, we propose 3 aims. In specific aim 1, we will breed the Chrna5 null mutation onto each of the B6-ChrA/J chromosome substitution strains (CSS) and identify chromosomes that harbor modifier genes for the effect of Chrna5 deletion on three nicotine behaviors, oral nicotine intake, somatic signs of nicotine withdrawal, and nicotine conditioned place preference. For specific aim 2, we will fine map those chromosomes that harbor modifier genes using sequential congenic strains. Typically, 3 generations of congenic strains starting from a CSS strain provides mapping resolution equivalent to that of any high resolution mapping population. Finally, in specific aim 3, we will use RNA-seq to identify genes whose expression is altered by the identified modifier genes. Importantly, we will use a state of the art genetic strategy that will allow us to examine gene expression in a neural cell population that is highly relevant to the behaviors: Chrna5 expressing cells of the interpeduncular nucleus. By combining the results of this aim with modifier loci identified through aims 1 and 2, we expect to narrow the list of potential candidate modifier genes and identify pathways specifically impacted by the modifier genes. In short, we believe that this strategy will lead to the identification of previously unknown genes and/or genetic pathways that contribute to the physiological and/or molecular processes important for the response to nicotine. These genes and/or pathways may serve as novel targets for the development of new pharmacotherapies to aid in smoking cessation.

项目摘要/摘要 少于十分之一的人试图戒烟的人仍戒烟一年。这个较差的退出率是 在某种程度上，当前用来帮助戒烟的药物仅适度而被驱动 有效，充其量。那是迫切需要开发对吸烟更有效的新型药物 停止。该项目的目的是使用新型的遗传策略来确定新的生物学目标 新型戒烟药物的潜在发展。遗传策略基于确定 改变CHRNA5中无效突变的小鼠中尼古丁反应的修饰基因，该基因是代码的基因 对于烟碱受体α5亚基。实际上，修饰剂基因是有助于物理和/或的基因 对于感兴趣的行为很重要，但通常没有发现的分子过程 它们修改的基因中没有扰动。因为CHRNA5中的变体改变了尼古丁的风险 对人类的依赖和啮齿动物的研究清楚地表明，Chrna5对许多尼古丁至关重要 相关行为，我们认为识别改变ChRNA5缺失对尼古丁影响的基因 行为将发现与尼古丁依赖性相关的新基因，这些基因可能是新颖的新目标 戒烟药物治疗。重要的是，我们计划筛选修饰符的行为不是 仅取决于CHRNA5，但也取决于内侧Habenula-IPN途径，神经途径 人们认为这在尼古丁依赖性中起着至关重要的作用。确定遗传修饰符的影响 CHRNA5删除尼古丁行为，我们提出了3个目标。在特定的目标1中，我们将繁殖CHRNA5 null 突变到每个B6-CHRA/J染色体取代菌株（CSS）上，并鉴定染色体 CHRNA5删除对三种尼古丁行为的影响，口服尼古丁摄入量的港口修饰符基因， 尼古丁提取的体迹象和尼古丁条件的位置偏好。对于特定目标2，我们将 精细地图使用顺序的先天性菌株携带修饰剂基因的染色体。通常，3 从CSS菌株开始的几代人菌株几代提供了相当于的映射分辨率 任何高分辨率映射人群。最后，在特定的目标3中，我们将使用RNA-Seq识别基因 其表达被确定的修饰符基因改变。重要的是，我们将使用艺术基因的状态 策略将使我们能够检查与神经元细胞群中的基因表达，这与 行为：ChRNA5表达枝间核的细胞。通过将此目标的结果与 通过目标1和2进行的修饰符，我们希望缩小潜在候选修饰符基因列表 并确定受修饰符基因特别影响的途径。简而言之，我们相信这种策略将 导致对先前未知的基因和/或遗传途径的鉴定，这些途径有助于 生理和/或分子过程对于对尼古丁的反应很重要。这些基因和/或途径 可以作为开发新药物疗法以帮助戒烟的新目标。