Semi-Volatile PCBs: Sources, Exposures, Toxicities

半挥发性多氯联苯：来源、暴露、毒性

• 批准号: 9085905
• 负责人: LARRY W ROBERTSON
• 金额: $ 14.89万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-05-12 至 2015-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9085905
• 关键词: Affect; Cell physiology; Cells; Cellular Structures; DNA; Data; Diet; Environment; Equilibrium; Event; Exposure to; Goals; Individual; Induced Mutation; Inhalation Exposure; Injection of therapeutic agent; Kinetics; Liver; Lung; Mediating; Metabolic Activation; Mitochondria; Nuclear; Organ; Oxidation-Reduction; Peroxidases; Polychlorinated Biphenyls; Population; Prostaglandin-Endoperoxide Synthase; Proteins; Quinones; Rattus; Reaction; Risk Assessment; Source; Subcellular structure; Sulfhydryl Compounds; Telomerase; Time; Toxic effect; Transgenic Organisms; base; chlorination; dechlorination; genotoxicity; macromolecule; pressure; semiquinone radicals; telomere; vapor

DESCRIPTION (provided by applicant): Airborne PCBs are those that have higher vapor pressures, lower chlorination, and are substrates for metabolic activation. We hypothesize that lower chlorinated airborne PCBs and their natural electrophilic metabolites interact with DNA and DNA-associated proteins and/or initiate oxidative events that alter the intracellular redox environment, thereby compromising cellular structures and functions. Our data show that PCBs are initiators in rat liver and that PCB3 (4-chlorobiphenyl) induces mutations in the liver and possibly lung of transgenic BigBlue rats after ip injection. Also, PCB3 metabolites cause various, compound-specific types of genotoxic damage in cells in culture. We have shown that prostaglandin synthase and myeloperoxidase bioactivate dihydroxy-PCBs and that the PCB-quinones can react with nucleophiles like GSH by Michael addition or a substitution reaction with dechlorination. We have also observed, for the first time, a PCB semiquinone radical in cells. We therefore propose to extend our studies to: 1) Examine the mechanisms of PCB genotoxicity by comparing nuclear vs. mitochondrial effects and elucidating PCB interactions with DNA-associated protein; 2) Investigate interactions of airborne PCBs and their metabolites with telomeres and telomerase; 3) Determine the reactions of PCB-semiquinone radicals and how factors, such as conjugation with thiols, affect this reactivity; 4) Analyze the genotoxicity of airborne PCBs after inhalation exposure and explore mechanisms to ameliorate/mediate against those effects. Jointly these studies may explain which and how PCBs are genotoxic, which organs, subcellular structures, and macromolecules are the targets, the mechanisms of these reactions, and whether these upset the delicate redox balance of the natural environment of the cell. Emphasis is placed on the kinetics and consequences of inhalation exposure to airborne PCBs. These data and dietary studies in the last Aim will provide a scientific basis for risk assessment and advice for stakeholders with the ultimate goal to protect highly-exposed individuals and populations.

描述（由申请人提供）：空气中的多氯联苯具有较高的蒸气压、较低的氯化性，并且是代谢活化的底物。我们假设，低氯空气传播的 PCB 及其天然亲电子代谢物与 DNA 和 DNA 相关蛋白相互作用和/或引发改变细胞内氧化还原环境的氧化事件，从而损害细胞结构和功能。我们的数据表明，PCB 是大鼠肝脏中的引发剂，而 PCB3（4-氯联苯）在腹腔注射后会诱导转基因 BigBlue 大鼠的肝脏和可能的肺部突变。此外，PCB3 代谢物会对培养细胞造成各种化合物特异性类型的基因毒性损伤。我们已经证明，前列腺素合酶和髓过氧化物酶可以生物活化二羟基-PCB，并且PCB-醌可以通过迈克尔加成或脱氯取代反应与GSH等亲核试剂发生反应。我们还首次在细胞中观察到 PCB 半醌自由基。因此，我们建议将我们的研究扩展到：1）通过比较核效应与线粒体效应并阐明 PCB 与 DNA 相关蛋白的相互作用来检查 PCB 遗传毒性的机制； 2）研究空气中的PCB及其代谢物与端粒和端粒酶的相互作用； 3) 确定 PCB-半醌自由基的反应以及诸如与硫醇的缀合等因素如何影响这种反应性； 4) 分析吸入暴露后空气中 PCB 的遗传毒性，并探索改善/调节这些影响的机制。这些研究共同可以解释哪些 PCB 具有遗传毒性以及如何具有遗传毒性，哪些器官、亚细胞结构和大分子是目标，这些反应的机制，以及这些反应是否会破坏细胞自然环境中微妙的氧化还原平衡。重点是吸入空气中多氯联苯的动力学和后果。最后一个目标中的这些数据和饮食研究将为利益相关者提供风险评估和建议的科学依据，最终目标是保护高度暴露的个人和人群。