title: Alveolar macrophage cytotoxicity for normal lung fibroblasts is mediated by nitric oxide release.
abstract: Nitric oxide (NO) released by activated alveolar macrophages (AM) can mediate effects on target cells and can also react with superoxide anion (O2-) to form peroxynitrite (PN), a highly cytotoxic product. The role of NO and PN in AM cytotoxicity for normal lung cells was investigated using co-cultures of rat lung fibroblasts (FB) and rat AM treated with lipopolysaccharide + interferon-gamma (LI). AM and FB, alone and in co-culture, were treated with LI for 5 days and cell viability measured. The culture media was analyzed for NO, TNF-alpha, O2-, and IL-1beta. A decreased FB viability was correlated with increased NO release by LI-activated AM. Pretreatment of co-cultures with the inducible NOS inhibitor L-NAME caused dose-related decreases in NO release by AM and increases in FB viability. Although TNF-alpha release was increased in co-cultures treated with LI, the viability of FB was not affected when cultures were treated with similar concentrations of TNF-alpha in the absence of AM. O2- could not be detected in the media and addition of superoxide dismutase (SOD) did not protect FB. These data suggest that neither O2- nor PN contributed to the loss of cell viability. Activated AM may kill normal rat lung FB through a NO-mediated pathway that does not involve PN.
authors: Respiratory Toxicology, Laboratory of Molecular Toxicology, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA. morgand@niehs.nih.gov
authors: Daniel L
authors: DL
authors: Morgan
authors: Cassandra J
authors: CJ
authors: Shines
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques / Q000379:methods; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D018920:Coculture Techniques / Q000379:methods; D003470:Culture Media / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D004353:Drug Evaluation, Preclinical; D004357:Drug Synergism; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D007371:Interferon-gamma / Q000009:adverse effects; D007375:Interleukin-1 / Q000096:biosynthesis / Q000737:chemistry / Q000502:physiology; D008070:Lipopolysaccharides / Q000009:adverse effects; D008168:Lung / Q000166:cytology; D016676:Macrophages, Alveolar / Q000187:drug effects / Q000473:pathology* / Q000648:ultrastructure; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D030421:Peroxynitrous Acid / Q000009:adverse effects / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013482:Superoxide Dismutase / Q000378:metabolism / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000737:chemistry / Q000187:drug effects; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000172:deficiency
chemical_list: D003470:Culture Media; D004338:Drug Combinations; D007375:Interleukin-1; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D030421:Peroxynitrous Acid; D009569:Nitric Oxide; C002744:3-nitrotyrosine; D014443:Tyrosine; D007371:Interferon-gamma; D019001:Nitric Oxide Synthase; D013482:Superoxide Dismutase; D019331:NG-Nitroarginine Methyl Ester