Combustion-Generated EPFRs: Assessing Cardiovascular Risks of Exposure

项目概要/摘要：项目2 颗粒物（PM）始终与心肺和心血管死亡率相关。尽管 暴露的风险，鲜为人知的机制PM介导的毒性。我中心 表明，有害有机物或污染土壤的热处理（TT）产生的PM排放， 超级基金的网站产生环境持久性自由基（EPFRs）。EPFR是一种独特的粒子- 在生物系统中能够氧化还原循环以产生活性氧（ROS）的污染物系统。 EPFR存在于污染的超级基金土壤和空气中的PM附近的工业化超级基金网站。我们 先前的超级基金项目集中于EPFR在调节心脏功能和疾病中的作用。虽然 吸入EPFR降低了基线心功能，我们发现这些影响是继发于 肺血管阻力的变化。这些血管效应的潜在机制尚不清楚; 然而，我们初步数据表明，EPFR介导的芳香烃受体（AhR）激活 在肺上皮细胞中导致血管活性因子的释放可能起重要作用 病理生理作用我们的中心假设是EPFR介导的AhR在气-血 血管活性介质的界面和动员导致肺和肺动脉的激活/功能障碍， 全身血管系统，导致心血管疾病。为了检验这一假设，具体目标1将检验 EPFR介导的肺上皮AhR激活是否是肺上皮细胞中 压力和舒张期充盈减少是EPFR诱导的心功能不全的基础。在建立 血管作为损伤的位点，具体目标2将阐明血管损伤的细胞机制， 测试EPFR是否通过激活AhR诱导血管功能障碍。在这两个目标中，控制同窝仔 小鼠和肺泡II型AhR特异性缺陷的小鼠将亚慢性暴露于EPFR， EPFR PM，或使用最近设计的吸入系统过滤的空气。Millar压力容积导管将 用于测量暴露小鼠的左心室功能和肺动脉压。遥测装置 将被用来记录血压。内皮依赖性血管反应性，以及两者的标志物 将评估内皮功能障碍和活化。具体目标3将确定一个推定的配体促进 EPFR诱导的AhR激活，并测试该代谢产物是否与EPFR介导的血管生成相关。 功能障碍与项目1合作，该目标将使用新的质谱方法来识别 并表征EPFR诱导的脂质氧化产物，其可用作内源性AhR激动剂， 我们可以将这些代谢物的组织和血液水平与血管功能障碍联系起来。完成这些 目的将提供重要的新数据，将上皮细胞中EPFR介导的氧化应激，AhR激活， 和心血管疾病。这一信息对于评估居住在现场附近的人所面临的风险至关重要 利用TT技术对超级基金或其他危险废物进行补救。

Project Summary/Abstract: Project 2 Particulate matter (PM) is consistently associated with cardiopulmonary and cardiovascular mortality. Despite the risk of exposure, little is known about the mechanisms underlying PM-mediated toxicity. Our Center has shown that PM emissions from the thermal treatment (TT) of hazardous organics or contaminated soils at Superfund sites produce environmentally persistent free radicals (EPFRs). EPFRs are a unique particle- pollutant system capable of redox cycling to generate reactive oxygen species (ROS) in biological systems. EPFRs are present in contaminated Superfund soils and airborne PM near industrialized Superfund sites. Our prior Superfund project focused on the role of EPFRs in modulating cardiac function and disease. Although inhalation of EPFRs decreased baseline cardiac function, we found that these effects were secondary to changes in pulmonary vascular resistance. The mechanism(s) underlying these vascular effects are unknown; however, our preliminary data suggest that EPFR-mediated activation of the aryl hydrocarbon receptor (AhR) in pulmonary epithelial cells resulting in the release of vasoactive factors may play an important pathophysiological role. Our central hypothesis is that EPFR-mediated activation of AhR at the air-blood interface and mobilization of vasoactive mediators leads to activation/dysfunction of the pulmonary and systemic vasculature, resulting in cardiovascular disease. To test this hypothesis, Specific Aim 1 will test whether EPFR-mediated activation of the AhR in lung epithelium is responsible for the increase in pulmonary pressure and decreased diastolic filling that underlies EPFR induced cardiac dysfunction. After establishing the vasculature as the locus of injury, Specific Aim 2 will elucidate the cellular mechanisms of vascular injury by testing whether EPFRs induce vascular dysfunction via activation of the AhR. In both aims, control littermate mice and mice deficient in AhR specifically in alveolar type II will be exposed subchronially to EPFRs, non- EPFR PM, or filtered air using a recently designed inhalation system. Millar pressure-volume catheters will be used to measure left ventricular function and pulmonary arterial pressure in exposed mice. Telemetry devices will be used to record blood pressure. Endothelium-dependent vascular reactivity, as well as markers for both endothelial dysfunction and activation, will be assessed. Specific Aim 3 will identify a putative ligand promoting EPFR-induced AhR activation and test whether this metabolite is associated with EPFR-mediated vascular dysfunction. In collaboration with Project 1, this aim will use novel mass spectrometry approaches to identify and characterize EPFR-induced lipid oxidation products that may serve as endogenous AhR agonists so that we may correlate tissue and blood levels of these metabolites with vascular dysfunction. Completion of these Aims will provide important new data linking EPFR-mediated oxidative stress in epithelial cells, AhR activation, and cardiovascular disease. This information is critical for assessing risks to those living in proximity to sites using TT technologies to remediate Superfund or other hazardous wastes.