scholarly journals Arsenite Exposure of Cultured Airway Epithelial Cells Activates κB-dependent Interleukin-8 Gene Expression in the Absence of Nuclear Factor-κB Nuclear Translocation

1999 ◽  
Vol 274 (43) ◽  
pp. 31025-31033 ◽  
Author(s):  
Ilona Jaspers ◽  
James M. Samet ◽  
William Reed
Keyword(s):  
Gene Expression ◽  
Epithelial Cells ◽  
Nuclear Translocation ◽  
Nuclear Factor Κb ◽  
Airway Epithelial Cells ◽  
Interleukin 8 ◽  
Nuclear Factor ◽  
Airway Epithelial

Nuclear Factor-κB–Dependent Induction of Interleukin-8 Gene Expression by Tumor Necrosis Factor : Evidence for an Antioxidant Sensitive Activating Pathway Distinct From Nuclear Translocation

Blood ◽  
1999 ◽  
Vol 94 (6) ◽  
pp. 1878-1889 ◽  
Author(s):  
Spiros Vlahopoulos ◽  
Istvan Boldogh ◽  
Antonella Casola ◽  
Allan R. Brasier
Keyword(s):  
Gene Expression ◽  
Tumor Necrosis Factor ◽  
Transcriptional Activation ◽  
Tumor Necrosis ◽  
Nuclear Translocation ◽  
Gene Transfection ◽  
Nuclear Factor Κb ◽  
Interleukin 8 ◽  
Nuclear Factor ◽  
Necrosis Factor

Tumor necrosis factor  (TNF) is a pluripotent activator of inflammation by inducing a proinflammatory cytokine cascade. This phenomenon is mediated, in part, through inducible expression of the CXC chemokine, interleukin-8 (IL-8). In this study, we investigate the role of TNF-inducible reactive oxygen species (ROS) in IL-8 expression by “monocyte-like” U937 histiocytic lymphoma cells. TNF is a rapid activator of IL-8 gene expression by U937, producing a 50-fold induction of mRNA within 1 hour of treatment. In gene transfection assays, the effect of TNF requires the presence of an inducible nuclear factor-κB (NF-κB) (Rel A) binding site in the IL-8 promoter. TNF treatment induces a rapid translocation of the 65 kD transcriptional activator NF-κB subunit, Rel A, whose binding in the nucleus occurs before changes in intracellular ROS. Pretreatment (or up to 15 minutes posttreatment) relative to TNF with the antioxidant dimethyl sulfoxide (DMSO) (2% [vol/vol]) blocks 80% of NF-κB–dependent transcription. Surprisingly, however, DMSO has no effect on inducible Rel A binding. Similar selective effects on NF-κB transcription are seen with the unrelated antioxidants, N-acetylcysteine (NAC) and vitamin C. These data indicate that TNF induces a delayed ROS-dependent signalling pathway that is required for NF-κB transcriptional activation and is separable from that required for its nuclear translocation. Further definition of this pathway will yield new insights into inflammation initiated by TNF signalling.

Mechanism of dexamethasone-mediated interleukin-8 gene suppression in cultured airway epithelial cells

2001 ◽  
Vol 280 (1) ◽  
pp. L107-L115 ◽  
Author(s):  
Mary Mann-Jong Chang ◽  
Maya Juarez ◽  
Dallas M. Hyde ◽  
Reen Wu
Keyword(s):  
Gene Expression ◽  
Protein Synthesis ◽  
Epithelial Cells ◽  
Actinomycin D ◽  
Airway Epithelial Cells ◽  
Interleukin 8 ◽  
Transcriptional Level ◽  
Dependent Manner ◽  
Airway Epithelial ◽  
New Protein

The effects of dexamethasone, a glucocorticoid analog, on interleukin 8 (IL-8) gene expression were studied in cultures of primary human tracheobronchial epithelial cells and an immortalized human bronchial epithelial cell line, HBE1 cells. Dexamethasone inhibited IL-8 mRNA and protein expression in a concentration- and time-dependent manner. The inhibition did not occur at the transcriptional level since both nuclear run-on activity and IL-8 promoter-reporter gene expression assay revealed no significant effect. Instead, there was a change in IL-8 mRNA stability in dexamethasone-treated cultures. Under actinomycin D treatment, IL-8 mRNA was quite stable in dexamethasone-depleted cultures, while in dexamethasone-pretreated cultures, IL-8 message was rapidly degraded within the first hour, then leveled off. When dexamethasone and actinomycin D were added simultaneously to dexamethasone-depleted cultures, IL-8 mRNA remained rather stable. When cycloheximide was used to inhibit new protein synthesis, dexamethasone-dependent inhibition was not observed. These results suggest that a posttranscriptional mechanism, which requires dexamethasone-dependent new protein synthesis, is involved in the regulation of IL-8 mRNA by dexamethasone in airway epithelial cells.

Nuclear Factor-κB–Dependent Induction of Interleukin-8 Gene Expression by Tumor Necrosis Factor : Evidence for an Antioxidant Sensitive Activating Pathway Distinct From Nuclear Translocation

Blood ◽  
1999 ◽  
Vol 94 (6) ◽  
pp. 1878-1889 ◽  
Author(s):  
Spiros Vlahopoulos ◽  
Istvan Boldogh ◽  
Antonella Casola ◽  
Allan R. Brasier
Keyword(s):  
Gene Expression ◽  
Tumor Necrosis Factor ◽  
Transcriptional Activation ◽  
Tumor Necrosis ◽  
Nuclear Translocation ◽  
Gene Transfection ◽  
Nuclear Factor Κb ◽  
Interleukin 8 ◽  
Nuclear Factor ◽  
Necrosis Factor

Abstract Tumor necrosis factor  (TNF) is a pluripotent activator of inflammation by inducing a proinflammatory cytokine cascade. This phenomenon is mediated, in part, through inducible expression of the CXC chemokine, interleukin-8 (IL-8). In this study, we investigate the role of TNF-inducible reactive oxygen species (ROS) in IL-8 expression by “monocyte-like” U937 histiocytic lymphoma cells. TNF is a rapid activator of IL-8 gene expression by U937, producing a 50-fold induction of mRNA within 1 hour of treatment. In gene transfection assays, the effect of TNF requires the presence of an inducible nuclear factor-κB (NF-κB) (Rel A) binding site in the IL-8 promoter. TNF treatment induces a rapid translocation of the 65 kD transcriptional activator NF-κB subunit, Rel A, whose binding in the nucleus occurs before changes in intracellular ROS. Pretreatment (or up to 15 minutes posttreatment) relative to TNF with the antioxidant dimethyl sulfoxide (DMSO) (2% [vol/vol]) blocks 80% of NF-κB–dependent transcription. Surprisingly, however, DMSO has no effect on inducible Rel A binding. Similar selective effects on NF-κB transcription are seen with the unrelated antioxidants, N-acetylcysteine (NAC) and vitamin C. These data indicate that TNF induces a delayed ROS-dependent signalling pathway that is required for NF-κB transcriptional activation and is separable from that required for its nuclear translocation. Further definition of this pathway will yield new insights into inflammation initiated by TNF signalling.

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