Salivary Biomarkers (DNA, RNA and Cortisol), Life Stress and Nicotine Dependence

描述(申请人提供)：该项目的广泛目标是为研究确定唾液生物标记物奠定基础，这些生物标记物可以预测个人的脆弱性：(A)进展为尼古丁依赖；(B)由于暴露于生活压力，成年后最终变得依赖尼古丁。拟议研究的特点是使用基于访谈的生活压力评估来提供对慢性和间歇性压力的准确和可靠的测量，以及识别容易获得的唾液生物标记物的初步步骤，这些生物标记物可以识别暴露在更高水平的慢性压力下的个人。该项目有可能通过确定遗传x环境(GxE)的相互作用来推动药物滥用预防和干预研究，这可能有助于解释旨在防止烟草使用的开始和尼古丁依赖的进展或维持戒烟的干预措施的成败。拟议的评估包括在20/21岁(n=390)进行两个队列的评估，包括收集唾液以提取DNA以评估已知与应激-奖励途径相关的候选基因的多态性，收集唾液以提取候选基因和基因组范围的基因表达，以及在20/21岁使用最先进的评估工具对慢性和间歇性应激进行系统的基于背景的评估。这项评估的数据将与来自两个队列的其他多来源/多受访者数据结合起来，这些数据来自正在进行的一项为期11年的纵向研究，该研究探讨了物质使用的病因，包括尼古丁依赖，并结合了评估20/21岁实验室诱导压力反应的皮质醇反应性的数据。为了实现这一广泛的目标，我们建议解决以下目标：(1)通过在慢性和间歇性应激的背景下，从已知与应激奖励途径相关的特定候选基因的多态的发生，确定预测从青春期到成年期以及跨青年的尼古丁依赖变化的GxE交互作用；(2)评估特定基因多态与皮质醇活性之间的关联，以响应实验室诱导的应激源，并通过检测成年初期遗传多态和生活应激交互作用对皮质醇失调调节的影响来评估GxE交互作用对皮质醇失调调节的影响；以及(3)评估唾液转录组是否包含用于识别具有慢性应激基因表达特征的个体的RNA生物标志物，使用来自24个经历最多生活应激和24个最小应激个体的RNA样本。我们计划通过对单个候选基因的基因表达分析来验证先前在淋巴细胞中识别的慢性应激的现有功能基因组特征，并将通过全基因组和候选基因表达分析来发现、确认和验证新的候选基因。公共卫生相关性：该项目有可能通过确定遗传x环境(GxE)相互作用来推进药物滥用预防和干预研究，这可能有助于解释旨在防止烟草使用开始和发展为尼古丁依赖或维持戒烟的干预措施的成败。结果可能会指导为特定个体选择量身定做的干预措施。

DESCRIPTION (provided by applicant): The broad goal of this project is to lay the foundation for research identifying salivary biomarkers that are predictive of the vulnerability of individuals to (a) progress toward nicotine dependence and (b) ultimately to become dependent on nicotine by emerging adulthood, given their exposure to life stress. Features of the proposed research is the use of an interview-based life stress assessment to provide a precise and reliable measurement of chronic and episodic stress, and initial steps in the identification of easily obtained salivary biomarkers that identify individuals who are exposed to greater levels of chronic stress. This project has the potential to advance drug abuse prevention and intervention research through identifying Genetic x Environment (GxE) interactions, which may help to explain the success or failure of interventions designed to prevent the initiation of tobacco use and the progression to nicotine dependence, or to maintain cessation. The proposed assessment with two cohorts at age 20/21 (n = 390) includes saliva collection for DNA extraction to assess polymorphisms of candidate genes known to be related to the stress-reward pathway, saliva collection for RNA extraction for candidate gene and genome wide gene expression, and a systematic contextual based assessment of chronic and episodic stress, using state-of-the-art assessment tools, at age 20/21. The data from this assessment will be integrated with other multi-source/multi-respondent data from two cohorts from an ongoing eleven-year longitudinal study examining the etiology of substance use, including nicotine dependence, combined with data assessing cortisol reactivity in response to laboratory induced stress, at age 20/21. To accomplish this broad goal, we propose to address the following aims: (1) Identify GxE interactions which predict change in nicotine dependence across from adolescence to emerging adulthood and across youth from the occurrence of polymorphisms of specified candidate gene known to be related to the stress reward pathway in the context of the experience of chronic and episodic stress; (2) Assess the association between specific genetic polymorphisms and cortisol reactivity in response to a laboratory induced stressor and assess the effect of GxE interactions on cortisol dysregulation through examining the effect of the interaction of genetic polymorphisms and life stress in emerging adulthood on cortisol dysregulation; and (3) Evaluate whether the salivary transcriptome contains RNA biomarkers for the identification of individuals with the gene expression signature of chronic stress using RNA samples from 24 individuals who experience the most life stress and 24 individuals with the least stress. We plan to validate an existing functional genomic signature of chronic stress previously identified in lymphocytes by performing gene expression analysis of individual candidate genes, and we will discover, confirm and validate novel candidate genes by performing genome-wide and candidate gene expression analysis. PUBLIC HEALTH RELEVANCE: This project has the potential to advance drug abuse prevention and intervention research through identifying Genetic x Environment (GxE) interactions, which may help to explain the success or failure of interventions designed to prevent the initiation of tobacco use and the progression to nicotine dependence, or to maintain cessation. Results may guide the selection of tailored interventions for specific individuals.