Oxidative stress activates anion exchange protein 2  and AP-1 in airway epithelial cells

Anion exchange protein 2 (AE2) is a membrane-bound protein that mediates chloride-bicarbonate exchange. In addition to regulating intracellular pH and cell volume, AE2 exports superoxide (O[Formula: see text]·) to the extracellular matrix in an HCO[Formula: see text]-dependent process. Given this ability to export O[Formula: see text]·, we hypothesized that expression of AE2 in the lung is regulated by oxidative stress. AE2 mRNA and protein expression was measured by RT-PCR and Western blot analysis, respectively, in differentiated human bronchial epithelial cells exposed to H2O2 (100 μM). Alterations in in vivo AE2 protein expression were evaluated in lung tissue of rats exposed to 70% O2. The role of transcription factor activator protein (AP)-1 in oxidant regulation of AE2 was evaluated by EMSA and by immunoblotting of nuclear phospho-c- jun. Results show increased AE2 mRNA and protein expression after oxidant exposure. This was preceded by transient increases in DNA binding of AE2-specific AP-1 and phosphorylation of c- jun. This study demonstrates that AE2 expression is regulated by oxidative stress in airway epithelial cells and that this regulation correlates with activation of AP-1.

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Zn2+-induced IL-8 expression involves AP-1, JNK, and ERK activities in human airway epithelial cells

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00479.2005 ◽

2006 ◽

Vol 290 (5) ◽

pp. L1028-L1035 ◽

Cited By ~ 77

Author(s):

Yu-Mee Kim ◽

William Reed ◽

Weidong Wu ◽

Philip A. Bromberg ◽

Lee M. Graves ◽

...

Keyword(s):

Epithelial Cells ◽

Protein Expression ◽

Promoter Activity ◽

Fluorescent Protein ◽

Airway Epithelial Cells ◽

Epithelial Cell Line ◽

Airway Epithelial ◽

Human Airway ◽

Mrna And Protein Expression ◽

Human Airway Epithelial Cells

Exposure to zinc-laden particulate matter in ambient and occupational settings has been associated with proinflammatory responses in the lung. IL-8 is an important proinflammatory cytokine in the human lung and is induced in human airway epithelial cells exposed to zinc. In this study, we examined the cellular mechanisms responsible for Zn2+-induced IL-8 expression. Zn2+ stimulation resulted in pronounced increases in both IL-8 mRNA and protein expression in the human airway epithelial cell line (BEAS-2B). IL-8 promoter activity was significantly increased by Zn2+ exposure in BEAS-2B cells, indicating that Zn2+-induced IL-8 expression is transcriptionally mediated. Mutation of the activating protein (AP)-1 response element in an IL-8 promoter-enhanced green fluorescent protein construct reduced Zn2+-induced IL-8 promoter activity. Moreover, Zn2+ exposure of BEAS-2B cells induced the phosphorylation of the AP-1 proteins c-Fos and c-Jun. We observed that Zn2+ exposure induced the phosphorylation of ERK, JNK, and p38 MAPKs, whereas inhibition of ERK or JNK activity blocked IL-8 mRNA and protein expression in BEAS-2B cells treated with Zn2+. In addition, we investigated the role of protein tyrosine phosphatases in the activation of signaling by Zn2+. Zn2+ treatment inhibited ERK- and JNK-directed phosphatase activities in BEAS-2B cells. These results suggested that Zn2+-induced inhibition of phosphatase activity is an initiating event in MAPK and AP-1 activation that leads to enhanced IL-8 expression by human airway epithelial cells.

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Ozone effect on inflammatory and proteomic profile of human macrophages and airway epithelial cells

European Journal of Public Health ◽

10.1093/eurpub/ckaa166.102 ◽

2020 ◽

Vol 30 (Supplement_5) ◽

Author(s):

L Falcone ◽

E Aruffo ◽

P Di Carlo ◽

P Del Boccio ◽

M C Cufaro ◽

...

Keyword(s):

Oxidative Stress ◽

Air Pollution ◽

Epithelial Cells ◽

Cell Lines ◽

Urban Areas ◽

Airway Epithelial Cells ◽

Airway Epithelial ◽

Proteomics Analysis ◽

Human Macrophages ◽

Tnf Α

Abstract Background Reactive oxygen species (ROS) and oxidative stress in the respiratory system are involved in lung inflammation and tumorigenesis. Ozone (O3) is one of the main components of air pollution in urban areas able to act as strong pro-oxidant agent, however its effects on human health is still poorly investigated. In this study the effect of O3 has been evaluated in THP-1 monocytes differentiated into macrophages with PMA and in HBEpC (primary human bronchial epithelial) cells, two model systems for in vitro studies and translational research. Methods Cell viability, ROS and pro-inflammatory cytokines like interleukin-8(IL-8) and tumor necrosis factor(TNF-α) have been tested in the above-mentioned cell lines not exposed to any kind of pollution (basal condition-b.c.) or exposed to O3 at a concentration of 120 ppb. In HBEpC a labelfree shotgun proteomics analysis has been also performed in the same conditions. Results Ozone significantly increased the production of IL-8 and TNF-α in THP-1 whereas no changes were shown in HBEpC. In both cell lines lipopolysaccharide(LPS) caused an increase of IL-8 and TNF-α production in b.c. and O3 treatment potentiated this effect. Ozone exposure increased ROS formation in a time dependent manner in both cell lines and in THP-1 cells a decrease in catalase activity was also shown. Finally, according to these data, functional proteomics analysis revealed that in HBEpC exposure to O3 many differential proteins are related to oxidative stress and inflammation. Conclusions Our results indicate that O3, at levels that can be reached in urban areas, causes an increase of pro-inflammatory agents either per se or potentiating the effect of immune response stimulators in cell models of human macrophages and human airway epithelial cells. Interestingly, the proteomic analysis showed that besides the dysregulated proteins, O3 induced the expression of AKR1D1 and AKR1B10, proteins recognized to play a significant role in cancer development. Key messages This study adds new pieces of information on the association between O3 exposure and detrimental effects on respiratory system. This study suggests the need for further research on the mechanisms involved and for a continued monitoring/re-evaluation of air pollution standards aimed at safeguarding human health.

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Transgenic overexpression of β2-adrenergic receptors in airway epithelial cells decreases bronchoconstriction

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.2000.279.2.l379 ◽

2000 ◽

Vol 279 (2) ◽

pp. L379-L389 ◽

Cited By ~ 24

Author(s):

Dennis W. McGraw ◽

Susan L. Forbes ◽

Judith C. W. Mak ◽

David P. Witte ◽

Patricia E. Carrigan ◽

...

Keyword(s):

Epithelial Cells ◽

Airway Epithelium ◽

Adrenergic Receptors ◽

Airway Epithelial Cells ◽

Airway Responsiveness ◽

Ozone Exposure ◽

Clara Cell ◽

Whole Body ◽

Airway Epithelial

Airway epithelial cells express β2-adrenergic receptors (β2-ARs), but their role in regulating airway responsiveness is unclear. With the Clara cell secretory protein (CCSP) promoter, we targeted expression of β2-ARs to airway epithelium of transgenic (CCSP-β2-AR) mice, thereby mimicking agonist activation of receptors only in these cells. In situ hybridization confirmed that transgene expression was confined to airway epithelium, and autoradiography showed that β2-AR density in CCSP-β2-AR mice was approximately twofold that of nontransgenic (NTG) mice. Airway responsiveness measured by whole body plethysmography showed that the methacholine dose required to increase enhanced pause to 200% of baseline (ED200) was greater for CCSP-β2-AR than for NTG mice (345 ± 34 vs. 157 ± 14 mg/ml; P < 0.01). CCSP-β2-AR mice were also less responsive to ozone (0.75 ppm for 4 h) because enhanced pause in NTG mice acutely increased to 77% over baseline ( P < 0.05) but remained unchanged in the CCSP-β2-AR mice. Although both groups were hyperreactive to methacholine 6 h after ozone exposure, the ED200for ozone-exposed CCSP-β2-AR mice was equivalent to that for unexposed NTG mice. These findings show that epithelial cell β2-ARs regulate airway responsiveness in vivo and that the bronchodilating effect of β-agonists results from activation of receptors on both epithelial and smooth muscle cells.

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