Pulmonary alveolar epithelial inducible NO synthase gene expression: regulation by inflammatory mediators.
Nitric oxide (.NO) is a short-lived mediator that can be induced by different cytokines and lipopolysaccharide (LPS) in a variety of cell types and produces many physiological and metabolic changes in target cells. In the current study, we show that a combination of cytokines, LPS, and zymosan-activated serum (ZAS; called for convenience cytomix Z) induces production of high concentrations of the NO oxidation products nitrite (NO2-) and nitrate (NO3-) by cultured rat fetal lung epithelial type II cells in a time-dependent fashion. Interferon-gamma and tumor necrosis factor-alpha alone did not significantly affect .NO synthesis, whereas ZAS, LPS, and interleukin-1 beta caused only a modest increase in formation of .NO oxidation products. Production of NO2- and NO3- was inhibited by NG-monomethyl-L-arginine and cyclohexmide. After exposure of these cells to a combination of the above cytokines, Escherichia coli LPS, and ZAS (cytomix Z), enhanced inducible nitric oxide synthase (iNOS) expression was indicated by an elevation in steady-state mRNA specific for iNOS (via Northern blot analysis) and increased immunofluorescence for iNOS after cell permeabilization, incubation with anti-iNOS antibody, and treatment with Cy3.18-conjugated rabbit-specific antibody. The extent of inflammatory mediator-induced.NO production by alveolar epithelium, which exceeds that of other lung cell types, reveals new insight into mechanisms of pulmonary host defense and pathways of free radical-mediated lung injury.
Gutierrez
H H
HH
Department of Pediatrics, University of Alabama at Birmingham 35233.
Pitt
B R
BR
Schwarz
M
M
Watkins
S C
SC
Lowenstein
C
C
Caniggia
I
I
Chumley
P
P
Freeman
B A
BA
D000594:Amino Acid Oxidoreductases / Q000037:antagonists & inhibitors / Q000235:genetics*; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001769:Blood; D002478:Cells, Cultured; D016207:Cytokines / Q000494:pharmacology*; D004848:Epithelium / Q000201:enzymology; D005260:Female; D005455:Fluorescent Antibody Technique; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D009566:Nitrates / Q000378:metabolism; D019001:Nitric Oxide Synthase; D009573:Nitrites / Q000378:metabolism; D011247:Pregnancy; D011650:Pulmonary Alveoli / Q000196:embryology / Q000201:enzymology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015054:Zymosan / Q000494:pharmacology; D019323:omega-N-Methylarginine
D016207:Cytokines; D008070:Lipopolysaccharides; D009566:Nitrates; D009573:Nitrites; D019323:omega-N-Methylarginine; D015054:Zymosan; D001120:Arginine; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases