Mechanism of RSV-induced IL-8 gene expression in A549 cells before viral replication.
Previous studies demonstrated that respiratory syncytial virus (RSV) infection of A549 cells induced interleukin (IL)-8 gene expression and protein release from the cells as early as 2 h after treatment [M. A. Fiedler, K. Wernke-Dollries, and J. M. Stark. Am. J. Physiol. 269 (Lung Cell. Mol. Physiol. 13): L865-L872, 1995; J. G. Mastronarde, M. M. Monick, and G. W. Hunninghake. Am. J. Respir. Cell Mol. Biol. 13: 237-244, 1995]. Furthermore, the effects of RSV at the 2-h time point were not dependent on viral replication. The studies reported here were designed to test the hypothesis that active and inactive RSV induce IL-8 gene expression in A549 cells at the 2-h time point by a mechanism dependent on the activation of the nuclear transcription factor NF-kappa B Northern blot analysis indicated that IL-8 gene expression occurred independent of protein synthesis 2 h after A549 cells were treated with RSV. Analysis of nuclear extracts from RSV-treated A549 cells by electrophoretic mobility shift assays demonstrated that NF-kappa B was activated as early as 15 min after RSV was added to the cells and remained activated for at least 90 min. In contrast, baseline levels of NF-IL-6 and activator protein-1 (AP-1) did not change over this period of time. Deoxyribonuclease footprint analysis of a portion of the 5'-flanking region of the IL-8 gene demonstrated two potential regions for transcription factor binding, which corresponded to the potential AP-1 binding site, and potential NF-IL-6 and NF-kappa B binding sites. Mutational analysis of the 200-bp 5'-untranslated region of the IL-8 gene demonstrated that activation of NF-kappa B and NF-IL-6 were required for RSV-induced transcriptional activation of the IL-8 gene.
Fiedler
M A
MA
Department of Pediatrics, Children's Hospital Research Foundation, Cincinnati, Ohio, USA.
Wernke-Dollries
K
K
Stark
J M
JM
D004252:DNA Mutational Analysis; D005786:Gene Expression Regulation; D006801:Humans; D016209:Interleukin-8 / Q000096:biosynthesis / Q000235:genetics*; D016328:NF-kappa B / Q000235:genetics; D018357:Respiratory Syncytial Virus Infections / Q000235:genetics* / Q000378:metabolism; D012136:Respiratory Syncytial Viruses / Q000502:physiology*; D014407:Tumor Cells, Cultured; D014779:Virus Replication
D016209:Interleukin-8; D016328:NF-kappa B