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.

项目概要/摘要 尝试戒烟的人中只有不到十分之一能够保持戒烟一年，这个戒烟率很低。 部分原因是目前用于帮助戒烟的药物效果有限 因此，非常需要开发对吸烟更有效的新药。 该项目的目标是使用一种新的遗传策略来识别新的生物靶点。 新型戒烟药物的潜在开发基于遗传策略的识别。 改变小鼠尼古丁反应的修饰基因，其编码基因 Chrna5 存在无效突变 对于烟碱受体 α5 亚基来说，修饰基因实际上是有助于生理和/或功能的基因。 对感兴趣的行为很重要但通常在环境中未被检测到的分子过程 因为 Chrna5 的变异会改变尼古丁的风险。 人类的依赖和啮齿类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相关的新基因，这些基因可能作为新的目标 重要的是，我们计划筛选的行为并不是戒烟药物疗法。 不仅依赖于 Chrna5，还依赖于内侧缰核-IPN 通路（一种神经通路） 这被认为在尼古丁依赖中发挥着关键作用，以确定影响尼古丁影响的遗传修饰因素。 Chrna5 对尼古丁行为的缺失，我们提出了 3 个目标，在具体目标 1 中，我们将培育 Chrna5 null。 突变到每个 B6-ChrA/J 染色体替代株 (CSS) 上，并鉴定出以下染色体： Chrna5缺失对三种尼古丁行为（口服尼古丁摄入量， 尼古丁戒断的躯体症状和尼古丁条件性位置偏好 对于具体目标 2，我们将进行研究。 使用连续的同源菌株对那些含有修饰基因的染色体进行精细定位，通常为 3 个。 从CSS菌株开始的同源菌株的世代提供了与 最后，在具体目标 3 中，我们将使用 RNA-seq 来识别基因。 重要的是，我们将使用最先进的遗传技术来改变其表达。 该策略将使我们能够检查与神经细胞群高度相关的基因表达 行为：脚间核的 Chrna5 表达细胞将这一目标的结果与此目标相结合。 通过目标 1 和 2 确定的修饰基因座，我们期望缩小潜在候选修饰基因的列表 并确定受修饰基因具体影响的途径。 简而言之，我们相信该策略将会实现。 导致鉴定出以前未知的基因和/或遗传途径，这些基因和/或遗传途径有助于 这些基因和/或途径对于尼古丁的反应很重要。 可以作为开发新药物疗法以帮助戒烟的新靶标。