title: Neopterin derivatives modulate toxicity of reactive species on Escherichia coli.
abstract: Neopterin and 7,8-dihydroneopterin are released by human monocytes/macrophages upon stimulation with interferon-gamma. In parallel, a panel of highly reactive species is produced by macrophages as part of their cytotoxic armature, which is directed against microbial and viral challenge and against malignant growth. Recently, neopterin and 7,8-dihydroneopterin were shown to modulate the action of reactive species in vitro. In this study we investigated the impact of neopterin and 7,8-dihydroneopterin on the toxicity of reactive species, namely chloramine-T, H2O2, hypochlorite, nitrite, and formaldehyde, respectively. We studied the growth inhibition of Escherichia Coli (E. coli) by these toxic agents and its modulation by neopterin and 7,8-dihydroneopterin. Bacterial growth was monitored by optical density of suspension cultures at 600 nm. Compared to control experiments, neopterin enhanced toxicity of all reactive species tested except formaldehyde, while 7,8-dihydroneopterin reduced activity of hypochlorite and chloramine-T. No significant impact of the pteridines could be established for H2O2-mediated and formaldehyde-mediated growth inhibition. The data support the concept that neopterin and 7,8-dihydroneopterin produced during immune response in humans could be important to modulate the action of reactive species released in parallel.
authors.affiliation: Institute for Medical Chemistry and Biochemistry, University of Innsbruck and Ludwig, Innsbruck, Austria.
authors.forename: I
authors.initials: I
authors.lastname: Wede
authors.forename: B
authors.initials: B
authors.lastname: Widner
authors.forename: D
authors.initials: D
authors.lastname: Fuchs
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002700:Chloramines / Q000494:pharmacology; D004202:Disinfectants / Q000494:pharmacology*; D004347:Drug Interactions; D004926:Escherichia coli / Q000187:drug effects* / Q000254:growth & development*; D005557:Formaldehyde / Q000494:pharmacology; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D019798:Neopterin / Q000494:pharmacology* / Q000031:analogs & derivatives; D011621:Pteridines / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D012973:Sodium Hypochlorite / Q000494:pharmacology; D012977:Sodium Nitrite / Q000494:pharmacology; D014105:Tosyl Compounds / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D002700:Chloramines; D004202:Disinfectants; D011621:Pteridines; D017382:Reactive Oxygen Species; D014105:Tosyl Compounds; C016300:chloramine-T; C000976:7,8-dihydroneopterin; D005557:Formaldehyde; D019798:Neopterin; D006861:Hydrogen Peroxide; D012973:Sodium Hypochlorite; D012977:Sodium Nitrite