Essential role of transcription factor nuclear factor-kappaB in regulation of interleukin-8 gene expression by nitrite reductase from Pseudomonas aeruginosa in respiratory epithelial cells.
Persistent infection with Pseudomonas aeruginosa increases interleukin-8 (IL-8) levels and causes dense neutrophil infiltrations in the airways of patients with chronic airway diseases. Recently, we have reported that nitrite reductase from P. aeruginosa induces the production of IL-8 in respiratory cells, including bronchial epithelial cells. To determine the molecular mechanism(s) of nitrite reductase-induced IL-8 expression in respiratory cells, A549 epithelial cells were transfected with plasmids containing serial deletions of the 5'-flanking region of the IL-8 gene and then exposed to nitrite reductase. Nitrite reductase significantly enhanced IL-8 gene promoter-driven reporter activity. This increased IL-8 gene expression was inhibited by mutating the nuclear factor-kappaB (NF-kappaB) binding element. Nitrite reductase enhanced nuclear localization of the NF-kappaB binding complex. Furthermore, nitrite reductase induced the degradation of IkappaBalpha, the major cytoplasmic inhibitor of NF-kappaB, and the expression of IkappaBalpha mRNA. These data support the critical role of the activation of NF-kappaB in nitrite reductase-induced IL-8 gene expression in airway epithelium.
Department of Preventive Medicine and AIDS Research, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan. n-mori@net.nagasaki-u.ac.jp
N
N
Mori
K
K
Oishi
B
B
Sar
N
N
Mukaida
T
T
Nagatake
K
K
Matsushima
N
N
Yamamoto
D004268:DNA-Binding Proteins / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D020672:I-kappa B Proteins; D016209:Interleukin-8 / Q000235:genetics*; D008168:Lung / Q000378:metabolism*; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000502:physiology*; D009572:Nitrite Reductases / Q000494:pharmacology*; D011401:Promoter Regions, Genetic; D011550:Pseudomonas aeruginosa / Q000201:enzymology*; D018808:Transcription Factor AP-1 / Q000502:physiology; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; D020672:I-kappa B Proteins; D016209:Interleukin-8; D016328:NF-kappa B; C000606204:NFKBIA protein, human; D018808:Transcription Factor AP-1; D000072000:NF-KappaB Inhibitor alpha; D009572:Nitrite Reductases