Induction of interleukin 8 (IL-8) production by Pseudomonas nitrite reductase in human alveolar macrophages and epithelial cells.
Interleukin-8 (IL-8) participates in the generation of dense neutrophil accumulations in bronchopulmonary infections caused by Pseudomonas aeruginosa (P. aeruginosa). We have recently reported that nitrite reductase, a bifunctional enzyme located in the periplasmic space of P. aeruginosa, induces IL-8 generation in bronchial epithelial cells (K. Oishi et al. Infect. Immun. 65: 2648-2655, 1997). We examined whether or not Pseudomonas nitrite reductase (PNR) could also stimulate human alveolar macrophages (AM) and pulmonary type II epithelial-like cells (A549) to induce IL-8 production and mRNA expression as well as the production of TNF alpha and IL-1beta. We demonstrated a time- and dose-dependent IL-8 protein synthesis and IL-8 mRNA expression, but no TNF alpha or IL-1beta production, by A549 cells in response to PNR. New protein translation was not required for PNR-mediated IL-8 mRNA expression in the same cells. Furthermore, simultaneous stimulation of PNR with serial doses of TNF alpha or IL-1beta resulted in additive IL-8 production in A549 cells. In adherent AM, PNR enhanced IL-8 protein synthesis and IL-8 mRNA expression in a time-dependent fashion. PNR similarly induced a time-dependent production of TNF alpha and IL-1beta by human adherent AM. Neutralization of TNF alpha or IL-1beta did not influence the levels of IL-8 production in adherent AM culture. We also evaluated whether the culture supernatants of the A549 cells or AM stimulated with PNR could similarly mediate neutrophil migration in vitro. When anti-human IL-8 immunoglobulin G was used for neutralizing neutrophil chemotactic factor (NCF) activities in the culture supernatants of these cells stimulated with 5 microg/ml of PNR, the mean percent reduction of NCF activities were 49-59% in A549 cells and 24-34% in AM. Our present data support that PNR directly stimulates AM and pulmonary epithelial cells to produce IL-8. PNR also mediates neutrophil migration, in part, through IL-8 production from AM and pulmonary epithelial cells. These data suggest the contribution of PNR to the pathogenesis of bronchopulmonary infections due to P. aeruginosa.
Sar
B
B
Department of Internal Medicine, Institute of Tropical Medicine, Nagasaki University, Japan. nekken@net.nagasaki-u.ac.jp
Oishi
K
K
Matsushima
K
K
Nagatake
T
T
D002448:Cell Adhesion; D002634:Chemotaxis, Leukocyte; D004847:Epithelial Cells / Q000187:drug effects / Q000276:immunology*; D006801:Humans; D007375:Interleukin-1 / Q000276:immunology / Q000494:pharmacology; D016209:Interleukin-8 / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D008168:Lung / Q000166:cytology* / Q000276:immunology; D016676:Macrophages, Alveolar / Q000187:drug effects / Q000276:immunology*; D009504:Neutrophils / Q000276:immunology; D009572:Nitrite Reductases / Q000276:immunology* / Q000494:pharmacology; D011550:Pseudomonas aeruginosa / Q000201:enzymology / Q000276:immunology*; D012333:RNA, Messenger / Q000096:biosynthesis; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology / Q000494:pharmacology
D007375:Interleukin-1; D016209:Interleukin-8; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D009572:Nitrite Reductases