Reactive oxygen and nitrogen intermediates increase transforming growth factor-β1 release from human epithelial alveolar cells through two different mechanisms
Reactive oxygen and nitrogen intermediates increase transforming growth factor-β1 release from human epithelial alveolar cells through two different mechanisms
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DOI：
10.1165/ajrcmb.21.1.3379
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发表时间：
1999-07-01
影响因子：
6.4
通讯作者：
Baud, L
中科院分区：
文献类型：
--
作者：
Bellocq, A;Azoulay, E;Baud, L
转化生长因子（TGF）-β 1是一种参与炎症过程后肺修复和纤维化机制的生长因子。我们试图研究炎症细胞产生活性氧中间体（ROI）或活性氮中间体（RNI）与肺泡上皮细胞表达TGF-β 1之间的联系。A549肺上皮细胞系暴露于ROI生成系统（黄嘌呤和黄嘌呤氧化酶）或RNI供体（S-亚硝基-N-乙酰基-青霉胺[SNAP]）促进了TGF-β 1释放的时间和剂量依赖性增加，如通过特异性酶联免疫吸附测定所测量的。在峰值时，TGF-β 1的水平是对照值的两倍。ROI对TGF-β 1释放的诱导被过氧化氢酶钝化，不受超氧化物歧化酶的影响，表明过氧化氢的参与。通过定量/竞争性逆转录聚合酶链反应测定，5，6-二氯-1-β-D-呋喃核糖基苯并咪唑（DRB）（一种特异性RNA聚合酶II抑制剂）也减弱了该反应，并伴随着TGF-β 1信使RNA的相应增加，表明转录机制和可能的其他下游机制参与其中。相反，RNI诱导的TGF-β 1释放不受DRB的影响，并被蛋白质合成抑制剂放线菌酮钝化，这表明涉及翻译和翻译后机制。这一反应需要环磷酸鸟苷（cGMP）介导的过程，因为（1）cGMP在SNAP处理的细胞培养液中积累：（2）SNAP诱导的TGF-β 1释放被sGMP依赖性蛋白激酶抑制剂KT 5823所抑制;和（3）细胞暴露于膜可穿透的二丁酰-cGMP或心房利钠因子也可获得类似的TGF-β 1释放增加，一种已知的颗粒鸟苷酸环化酶激动剂。这些数据表明，在体外暴露于ROI和RNI的人肺泡上皮细胞通过不同的机制增强TGF-β 1的释放。在体内，这种控制可能构成炎症和纤维化过程之间的分子联系。
Transforming growth factor (TGF)-beta 1 is a growth factor involved in the mechanisms of lung repair and fibrosis that follow inflammatory processes. We sought to examine the link between the generation of reactive oxygen intermediates (ROI) or reactive nitrogen intermediates (RNI) by inflammatory cells and the expression of TGF-beta 1 by alveolar epithelial cells. Exposure of the A549 lung epithelial cell line to either an ROI generating system (xanthine and xanthine oxidase) or an RNI donor (S-nitroso-N-acetyl-penicillamine [SNAP]) promoted a time- and dose-dependent increase in TGF-beta 1 release, as measured by a specific enzyme-linked immunosorbant assay. At the peak, the levels of TGF-beta 1 were twice the control values. The induction of TGF-beta 1 release by ROI was blunted by catalase and unaffected by superoxide dismutase, indicating the involvement of hydrogen peroxide. The response was also blunted by 5,6-dichloro- 1-beta-D-ribofuranosyl benzimidazole (DRB), a specific RNA polymerase II inhibitor, and accompanied by a corresponding increase in TGF-beta 1 messenger RNA, as measured by quantitative/competitive reverse transcription polymerase chain reaction, suggesting the involvement of transcriptional mechanisms and possibly other downstream mechanisms. In contrast, RNI-induced TGF-beta 1 release was unaffected by DRB and blunted by the protein synthesis inhibitor cycloheximide, suggesting the involvement of translational and post-translational mechanisms. This response required cyclic guanosine monophosphate (cGMP)-mediated processes because (I) immunoreactive cGMP accumulated in the culture medium of SNAP-treated cells: (2) SNAP-induced TGF-beta 1 release was blunted by KT 5823, an inhibitor of sGMP-dependent protein kinase; and (3) similar increase in TGF-beta 1 release was obtained by cell exposure to membrane-pennneable dibutyryl-cGMP or to atrial natriuretic factor, a known agonist of particulate guanylate cyclase. These data suggest that in vitro exposure of human alveolar epithelial cells to ROI and RNI enhances TGF-beta 1 release through different mechanisms. In vivo, this control may constitute a molecular link; between inflammatory and fibrotic processes.