title: Genotoxicity associated with NO production in macrophages and co-cultured target cells.
abstract: We previously used mouse macrophage-like RAW264.7 cells as an experimental system for the study of nitric oxide (NO)-associated genotoxicity under physiologically relevant conditions, and characterized genotoxic effects in the NO-producing cells. Here we report experiments utilizing a co-culture system enabling parallel studies of cytotoxic and genotoxic responses in co-cultured target cells as well as in macrophages stimulated to produce NO. We found that co-cultivation with macrophages stimulated to produce NO for 38-42 h resulted in significant increases in mutant fraction in the endogenous genes of target human TK6 and hamster CHO-AA8 cells and in the macrophages themselves, accompanied by a substantial decrease in cell viability. Addition of N-methyl-L-arginine, an NO synthase inhibitor, abrogated much of the cytotoxicity and genotoxicity in both target and macrophages cells, verifying the role of NO in the induction of these responses. We also showed that NO-associated genotoxic response in macrophages could be influenced by culture medium. Collectively, these results support the hypothesis that NO production by activated macrophages may contribute to genotoxic risks associated with chronic inflammation.
authors.affiliation: Biological Engineering Division and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: John C
authors.initials: JC
authors.lastname: Zhuang
authors.forename: Doris
authors.initials: D
authors.lastname: Lin
authors.forename: Charley
authors.initials: C
authors.lastname: Lin
authors.forename: Deepa
authors.initials: D
authors.lastname: Jethwaney
authors.forename: Gerald N
authors.initials: GN
authors.lastname: Wogan
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology; D016466:CHO Cells / Q000187:drug effects / Q000378:metabolism; D002460:Cell Line; D002934:Cinnamates; D018920:Coculture Techniques; D006224:Cricetinae; D004351:Drug Resistance; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D006921:Hygromycin B / Q000031:analogs & derivatives* / Q000494:pharmacology; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics / Q000378:metabolism; D007371:Interferon-gamma / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008214:Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D008262:Macrophage Activation / Q000187:drug effects / Q000235:genetics; D008264:Macrophages / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D009355:Neomycin / Q000494:pharmacology; D009569:Nitric Oxide / Q000096:biosynthesis* / Q000633:toxicity; D013937:Thymidine Kinase / Q000235:genetics / Q000378:metabolism; D019323:omega-N-Methylarginine / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D000970:Antineoplastic Agents; D002934:Cinnamates; D004791:Enzyme Inhibitors; D008070:Lipopolysaccharides; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D006921:Hygromycin B; C026273:hygromycin A; D007371:Interferon-gamma; D007041:Hypoxanthine Phosphoribosyltransferase; D013937:Thymidine Kinase; D009355:Neomycin