Synergistic inflammatory responses to metals associated with fuel oil ash

我们的初步研究目标是阐明与残油飞灰（ROFA）相关的金属如何引发和加剧肺部的炎症反应。我们的总体假设是：易感个体的肺巨噬细胞和上皮细胞在基因水平上对ROFA中的金属反应不成比例。通过预先存在的炎性病症对肺细胞的“引发”导致调节基因表达的信号转导途径内的协同扩增。具体目标是：1）确定ROFA中介导毒性及其致炎潜力的金属成分; 2）表征ROFA相关金属的毒性及其单独和组合诱导促炎细胞因子的能力; 3）建立负责增加细胞因子表达的分子机制; 4）建立氧化应激在金属诱导的细胞因子表达中的作用;和5）表征巨噬细胞和上皮细胞对金属的总体遗传反应。为了确定ROFA相关金属的炎症潜力，我们将通过气管内滴注将大鼠暴露于可溶性金属，并通过巨噬细胞和上皮细胞系以及原代细胞培养物评估肺部炎症和促炎介质对体外激发的反应。细胞将是巨噬细胞和上皮细胞系以及对体外激发作出反应的原代细胞培养物。细胞将是正常的或分别用细菌脂多糖或肿瘤坏死因子（TNF）-α预处理（“预处理”）。调节细胞因子基因表达的信号转导途径将在分子水平上阐明。将比较致敏和未致敏的巨噬细胞和上皮细胞对金属的反应差异基因表达，并鉴定差异表达的基因。氧化应激在控制这些基因调控的信号转导途径中的作用将被研究。我们预测，能够诱导细胞呼吸爆发的金属将引起提高生产。促炎细胞因子的表达。这种对环境或低水平金属的不适当反应将是理解所观察到的与空气中颗粒物浓度升高相关的发病率/死亡率增加的重要的第一步。

Our preliminary research objectives is to elucidate how metals associated with residual oil fly ash (ROFA) initiates and exacerbates the inflammatory response in the lung. Our overall hypothesis is: Lung macrophages and epithelial cells in susceptible individuals respond disproportionately at a genetic level to metals in ROFA. "Priming" of lung cells by a pre-existing inflammatory condition results in synergistic amplification within the signal transduction pathways regulating gene expression. Specific aims are: 1) To determine the metal constituents of ROFA that mediate toxicity and its inflammatory potential; 2) To characterize the toxicity of ROFA-associated metals and their ability to induce pro-inflammatory cytokines, individually and in combination; 3) To establish molecular mechanisms responsible for increased cytokine expressions; 4) To establish a role for oxidative stress in metal-induced cytokine expression; and 5) To characterize the overall genetic response of macrophages and epithelial cells to metals. To determine the inflammatory potential of ROFA-associated metals, we will expose rats to soluble metals by intratracheal instillation and assess pulmonary inflammation and pro-inflammatory mediators by macrophages and epithelial cell lines and primary cell cultures in response to an in vitro challenge. Cells will be either macrophages and epithelial cell lines and primary cell cultures in response to an vitro challenge. Cells will be either normal or pre-treated ("primed") with bacterial lipopolysaccharide or tumor necrosis factor (TNF)-alpha, respectively. Signal transduction pathways regulating cytokine gene expression will be elucidated at a molecular level. Differential gene expression in primed and unprimed- macrophages and epithelial cells in response to metals will be compared and differentially-expressed genes identified. A role for an oxidant stress in the signal transduction pathway controlling regulation of these genes will be examined. We predict that metals capable of inducing a cellular respiratory burst will elicit enhanced production. of pro-inflammatory cytokines in primed lung epithelium and macrophages. This inappropriate response to ambient or low levels of metals would be an important first step in understanding the observed increase in morbidity/mortality associated with elevated airborne particle concentrations.