Damera Gautam, Zhao Hengjiang, Wang Miao, Smith Michael, Kirby Christopher, Jester William F, Lawson John A, Panettieri Reynold A
University of Pennsylvania, Philadelphia, PA 19104-3403, USA.
Am J Physiol Lung Cell Mol Physiol. 2009 Apr;296(4):L674-83. doi: 10.1152/ajplung.90585.2008. Epub 2009 Feb 6.
Although ozone enhances leukocyte function and recruitment in airways, the direct effect of ozone in modulating structural cell-derived inflammatory mediators remains unknown. Using a coculture model comprised of differentiated human airway epithelial cells (NHBE) and smooth muscle cells (ASM), we postulate that ozone regulates IL-6 secretion in basal and cytokine-primed structural cells. Air-liquid interface (ALI) cultures of NHBE cells underwent differentiation as determined by mucin secretion, transepithelial electrical resistance (TEER), and ultrastructure parameters. Whereas TNF enhanced basal secretion of IL-6 (57 +/- 3%), ozone exposure at 0.6 ppm for 6 h augmented IL-6 levels in basal (41 +/- 3%) and TNF- (50 +/- 5%) primed cocultures compared with that derived from NHBE or ASM monolayers alone. Levels of PGE(2), 6-keto-PGF(1alpha), PGF(2alpha), and thromboxane B(2) (TxB(2)) levels in basal and TNF-primed cocultures revealed that ozone selectively enhanced PGE(2) production in TNF- (6 +/- 3-fold) primed cocultures, with little effect (P > 0.05) on diluent-treated cultures. In accordance with ozone-induced increases in PGE(2) levels, cyclooxygenase inhibition with indomethacin partially abolished IL-6 secretion. Surprisingly, indomethacin had little effect on constitutive secretion of IL-6 in cocultures, whereas indomethacin completely restored ozone-mediated TEER reduction in TNF-primed cocultures. Collectively, our data for the first time suggest a dual role of ozone in modulating IL-6 secretion and TEER outcomes in a PGE(2)-dependent (in presence of TNF stimulus) and -independent manner (in absence of cytokine stimulus).
尽管臭氧可增强气道中的白细胞功能和募集，但臭氧在调节结构细胞衍生的炎症介质方面的直接作用仍不清楚。我们使用由分化的人气道上皮细胞（NHBE）和平滑肌细胞（ASM）组成的共培养模型，推测臭氧可调节基础状态下以及细胞因子预处理后的结构细胞中白细胞介素-6（IL-6）的分泌。通过黏蛋白分泌、跨上皮电阻（TEER）和超微结构参数确定，NHBE细胞的气液界面（ALI）培养物发生了分化。肿瘤坏死因子（TNF）可增强IL-6的基础分泌（57±3%），而0.6 ppm的臭氧暴露6小时可使基础状态下（41±3%）以及TNF预处理（50±5%）的共培养物中的IL-6水平高于单独的NHBE或ASM单层培养物。基础状态下以及TNF预处理的共培养物中前列腺素E2（PGE2）、6-酮-前列腺素F1α（6-keto-PGF1α）、前列腺素F2α（PGF2α）和血栓素B2（TxB2）的水平显示，臭氧可选择性增强TNF预处理（6±3倍）的共培养物中PGE2的产生，而对稀释剂处理的培养物影响很小（P>0.05）。与臭氧诱导的PGE2水平升高一致，用吲哚美辛抑制环氧化酶可部分消除IL-6的分泌。令人惊讶的是，吲哚美辛对共培养物中IL-6的组成性分泌影响很小，而吲哚美辛可完全恢复TNF预处理的共培养物中臭氧介导的TEER降低。总的来说，我们的数据首次表明，臭氧在以PGE2依赖的方式（在存在TNF刺激时）和非依赖的方式（在不存在细胞因子刺激时）调节IL-6分泌和TEER结果方面具有双重作用。
