Endogenous nitric oxide inhibits neutrophil adherence to lung epithelial cells to modulate interleukin-8 release.
To investigate the effect of neutrophil adherence to epithelial cells on the release of interleukin 8 (IL-8), we measured neutrophil adherence in the presence or absence of IFN-gamma+TNF-alpha+IL-1beta (cytomix) stimulation on cultured A549 epithelial cells. The extent of neutrophil adherence to A549 epithelial cells was measured and the concomitant production of IL-8 and nitrite were assayed. The roles of adhesion molecules and nitrite in modulation of neutrophil adherence were examined by pretreatment with oversaturating ICAM-1 blocking antibody and L-NAME (1 mM), respectively. There was a time-dependent spontaneous and cytomix-induced release of IL-8 from epithelial cells, as well as a time-dependent increase in the magnitude of neutrophil adherence to epithelial cells. Stimulation of epithelial cells with cytomix induced a further increase in neutrophil adherence. Pretreatment with oversaturated ICAM-1 monoclonal antibody inhibited neutrophil adherence with or without cytomix stimulation. The inhibition of neutrophil adherence to epithelial cells with ICAM-1 monoclonal antibody or a semipermeable membrane downregulated the release of IL-8 with or without cytomix stimulation. Stimulation with cytomix decreased nitrite production. Both neutrophil adherence and L-NAME pretreatment significantly inhibited the production of nitrite. The inhibition of neutrophil adherence to epithelial cells with ICAM-1 monoclonal antibody or a semipermeable membrane upregulated nitrite production. Pretreatment with L-NAME failed to modify the spontaneous release of IL-8, but significantly enhanced the response to adherence and cytomix. In conclusion, endogenous nitric oxide may play a role in preventing neutrophil adherence to lung epithelial cells, thus modulating concomitant IL-8 release.
Lin
H C
HC
Department of Thoracic Medicine II, Chang Gung Memorial Hospital, Taipei, Taiwan.
Wang
C H
CH
Yu
C T
CT
Hwang
K S
KS
Kuo
H P
HP
D000911:Antibodies, Monoclonal / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology*; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D004338:Drug Combinations; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000276:immunology; D007371:Interferon-gamma / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology; D016209:Interleukin-8 / Q000378:metabolism*; D008168:Lung / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects / Q000502:physiology*; D009569:Nitric Oxide / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D004338:Drug Combinations; D007375:Interleukin-1; D016209:Interleukin-8; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1; D009569:Nitric Oxide; D007371:Interferon-gamma; D019331:NG-Nitroarginine Methyl Ester