NOVEL APPROACHES TO INVESTIGATE GENETIC CORRELATES OF SMOKING BEHAVIORS

项目摘要/摘要： 与吸烟有关的疾病仍然是可预防的死亡的最大原因。有很大的差距 戒烟治疗的改进存在，具有造福公众健康的巨大潜力：超过 每年有一半的美国吸烟者试图戒烟，但每年只有6%的人成功戒烟。吸烟的差异 表型，包括停药，有显著的遗传成分，但这种影响的绝大多数是 无法解释。对吸烟行为的遗传学研究揭示了这些变化的潜在机制 特征将进一步确定药物治疗的目标，并帮助改进个性化的戒烟治疗。 利用体内尼古丁新陈代谢实验的测量结果，我开发了一种预测性基因 解释70%口服尼古丁C氧化(主要尼古丁代谢)变化的模型 途径)，基于CYP2A6基因。模型预测与不同的 在进一步的受试者中测量香烟消费和戒烟的成功率。该模型还 让我展示了两个关键的新发现：对吸烟行为的独立影响 1)EGLn2基因的多态现象。低氧诱导因子Pro羟基酶，它启动一种 反应细胞缺氧的转录级联反应，以及2)在FMO3和CYP2B6中，进一步的尼古丁 可能具有重要肝外活动的代谢基因。这笔赠款的具体目的是：1) 开发包含三种尼古丁的尼古丁代谢的综合预测遗传模型 代谢途径及其相关基因，重点是细胞色素P4502A6、UGT和FMOS。改进后的 然后将模型应用于更多的样本，以确定尼古丁的遗传差异的影响 吸烟时的代谢表型；2)确定改变尼古丁代谢基因功能的变异和 演示它们的影响机制。我将特别关注蛋白质和信使核糖核酸的表达， 剪接，在人脑和肝脏样本中；3)确定EGLN2和其他低氧反应的变异 候选基因，并确定其对吸烟表型的影响机制。我的初步数据 表明与尼古丁依赖和香烟消费相关的EGLN2变体改变了相对的 不同EGLN25‘UTRmRNA剪接变异体的表达。我将确定基因和蛋白质的差异 在正常和低氧条件下培养的细胞中，EGLN2基因表达受其影响。的目标是 这项K01建议是为了在以下条件下获得统计人类遗传学和细胞培养的进一步培训 特别情况下，并将这一专门知识应用于药物滥用问题。

Project Summary/Abstract: Disease associated with cigarette smoking remains the largest cause of preventable death. A large margin for improvement in smoking cessation treatment exists, with great potential to benefit public health: more than half of American smokers attempt to quit every year, but only ~6% succeed annually. Differences in smoking phenotypes, including cessation, have significant genetic components, but the large majority of this influence is unexplained. Genetic studies of smoking behavior that reveal the mechanisms underlying variation in these traits will identify further targets for pharmacotherapy and aid in improving personalized cessation treatment. Utilizing measurements from an in vivo nicotine metabolism experiment, I developed a predictive genetic model that explains >70% of the variation in oral nicotine C-oxidation (the primary nicotine metabolism pathway), based on CYP2A6 genotype. Model predictions were significantly associated with different measures of cigarette consumption and smoking cessation success in further subjects. The model also allowed me to demonstrate two key novel findings: the independent influences upon smoking behaviors of polymorphisms in 1) EGLN2, a.k.a. Hypoxia Inducible Factor Prolyl Hydroxylase, which initiates a transcriptional cascade in response to cellular hypoxia, and 2) in FMO3 and CYP2B6, further nicotine metabolism genes that may have important extra-hepatic activity. The specific aims of this grant are: 1) Develop a comprehensive predictive genetic model of nicotine metabolism incorporating all three nicotine metabolism pathways and their associated genes, focusing on CYP2A6, the UGTs and FMOs. The improved model will then be applied in further samples to determine the influence of heritable differences in nicotine metabolism upon smoking phenotypes; 2) Identify variants that alter nicotine metabolism gene function and demonstrate the mechanisms of their effects. I will focus especially on protein and mRNA expression, and splicing, in human brain and liver samples; 3) Identify variants in EGLN2 and other hypoxia-response candidate genes, and determine the mechanisms of their effects on smoking phenotypes. My preliminary data indicate an EGLN2 variant associated with nicotine dependence and cigarette consumption alters the relative expression of different EGLN2 5'UTR mRNA splice-variants. I will identify differences in gene and protein expression influenced by EGLN2 genotype in cells cultured under normal and hypoxic conditions. The goal of this K01 proposal is to obtain further training in statistical human genetics and cell culture under special conditions and to apply this expertise to problems of substance abuse.