Characterization of Naphthalene DNA Adducts in Mice and Firefighters

项目概要/摘要 萘（NA）是一种简单的多环芳烃，作为一种有机污染物长期存在于环境中。 化石燃料燃烧以及烟草和其他产品燃烧的副产品。它无处不在的存在 导致普通人群的广泛接触。某些职业群体，如消防员， 暴露程度更高消防员也增加了某些类型癌症的发病率。na是 目前被国际癌症研究机构（IARC）列为2B类致癌物。 在小鼠和大鼠中有肿瘤形成的直接证据，但在小鼠和大鼠中没有NA致癌性的直接证据。 人类在这个时候NA暴露后小鼠和大鼠肿瘤形成的发病机制尚不清楚; 目前文献中提出了细胞毒性和遗传毒性机制。NA代谢导致 反应性中间体如1，2-环氧化物和反应性代谢物如1，4-和1，2- 萘醌（NAQ）。类似化合物的反应性醌和环氧化物代谢物，如 苯并[a]芘通过DNA加合物的形成发挥其致癌性。出版前 体内和体外数据已经证明NA代谢物可以与DNA形成加合物。的目的 研究是鉴定和定量小鼠肺以及小鼠和人血液中NA-DNA加合物， 消防员潜在遗传毒性的评估。将检验几个假设：1）循环反应性 NA代谢物，特别是NAQ，将在双肺中与DNA形成稳定的脱嘌呤加合物 2）循环白细胞中NA-DNA加合物的类型和丰度 将至少部分地反映肺中的加合物形成; 3）在循环中检测到的NA-DNA加合物的类型 白细胞从暴露的小鼠和消防员将是相似的;和4）暴露于火灾烟雾将增加NA- 消防员的DNA加合物水平这些假设将通过应用3个特定目标进行检验。在 目的1：鉴定和定量野生型小鼠吸入NA后形成的NA-DNA加合物 暴露，使用质谱法。在目标2中，我将剖析负责 在NA暴露小鼠的肺和循环白细胞中NA-DNA加合物的形成， 转基因小鼠模型（肝-Cpr-null、肝-Ephx 1-null和Cyp2abfgs-null）。在目标3中，我将描述 来自消防员和对照供体的血液标本中的NA-DNA加合物。该项目将提供直接 为NA-DNA加合物在体内的形成提供了证据，为今后的遗传毒性研究奠定了基础 获得证据，以支持更广泛的评估NA对消防员的致癌风险， 并可能对普通民众产生直接影响通过实施该项目， 在这个奖学金的帮助下，我将得到职业生涯所需的科学和专业技能的全面培训 作为学术界的独立研究员。

Project Summary/Abstract Naphthalene (NA), a simple polycyclic aromatic hydrocarbon, is persistently present in the environment as a byproduct of combustion of fossil fuels and burning of tobacco and other products. Its ubiquitous presence results in widespread exposure to the general population. Certain occupational groups, such as firefighters, have elevated levels of exposure. Firefighters also have increased incidences of certain types of cancer. NA is currently classified by the International Agency for Research on Cancer (IARC) as a Class 2B Carcinogen. There is direct evidence of tumor formation in mice and rats but no direct evidence of carcinogenecity of NA in humans at this time. The pathogenesis of tumor formation in mice and rats after exposure to NA is unclear; cytotoxic and genotoxic mechanisms are both proposed in the current literature. NA metabolism results in the generation of reactive intermediates such as 1,2-epoxide and reactive metabolites such as 1,4- and 1,2- naphthoquinone (NAQ). Reactive quinone and epoxide metabolites of similar compounds, such as benzo[a]pyrene, have been shown to enact their carcinogenecity through DNA adduct formation. Published ex vivo and in vitro data have demonstrated that NA metabolites can form adducts with DNA. The objective of this study is to identify and quantify NA-DNA adducts in mouse lung as well as mouse and human blood to enable assessment of potential genotoxicity in firefighters. Several hypotheses will be tested: 1) Circulating reactive NA metabolites, particularly NAQs, will form stable as well as depurinating adducts with DNA in both lung tissue and blood leukocytes in vivo; 2) the types and abundances of NA-DNA adducts in circulating leukocytes will at least partly reflect adduct formation in the lung; 3) the types of NA-DNA adducts detected in circulating leukocytes from exposed mice and firefighters will be similar; and 4) exposure to fire smoke will increase NA- DNA adduct levels in firefighters. These hypotheses will be tested through the application of 3 Specific Aims. In Aim 1, I will Identify and quantitate NA-DNA adducts formed in wild-type (WT) mice following NA inhalation exposure, with use of mass spectrometry methods. In Aim 2, I will dissect metabolic pathways responsible for NA-DNA adduct formation in the lung and circulating leukocytes of NA-exposed mice, with use of unique transgenic mouse models (liver-Cpr-null, liver-Ephx1-null, and Cyp2abfgs-null). In Aim 3, I will characterize NA-DNA adducts in blood specimens from firefighters and control donors. This project will provide direct evidence for the formation of NA-DNA adducts in vivo, lay the foundation for future studies of the genotoxicity of NA, obtain evidence to support more extensive assessments of the carcinogenic risks of NA to firefighters, and could have direct implications for the general population. Through the execution of this project and the help of this fellowship, I will be fully trained in scientific and professional skills necessary for my career advancement as an independent researcher in academia.