title: Fluorescence of 1,2-diaminoanthraquinone and its nitric oxide reaction product within macrophage cells.
abstract: Nitric oxide (NO) is involved in many biological processes. Aromatic ortho-diamine derivatives are commonly used in the fluorescence imaging of NO in living cells. ortho-diamino (o-diamino) compounds are believed to react with NO in an oxygenated medium leading to the formation of a triazole derivative. One such o-diamino compound, 1,2-diaminoanthraquinone (DAA), is a nontoxic probe for the detection of NO in living tissues and cells. The formation of the DAA triazole derivative (DAA-TZ) upon reaction of DAA with NO/O(2)  within cells has not been demonstrated previously. The aim of this study was to confirm that DAA-TZ is the species formed intracellularly when DAA reacts with NO in the presence of oxygen. The chemical synthesis and characterisation of DAA-TZ was performed together with intracellular studies of DAA and DAA-TZ. Raw 264.7 macrophages were loaded with the DAA or DAA-TZ under conditions of no-stimulation or stimulation with interferon-γ and lipopolysaccharide to produce NO. Confocal microscopy was used to image the DAA-loaded macrophage cells. Analysis of the emission spectra allowed precise discrimination of the fluorescence of each species in the macrophage cells, and confirmed the identity of DAA-TZ as the intracellular reaction product between DAA and NO in the presence of oxygen.
authors.affiliation: School of Chemistry, University of East Anglia, Norwich, Norfolk, UK.
authors.forename: María J
authors.initials: MJ
authors.lastname: Marín
authors.forename: Paul
authors.initials: P
authors.lastname: Thomas
authors.forename: Víctor
authors.initials: V
authors.lastname: Fabregat
authors.forename: Santiago V
authors.initials: SV
authors.lastname: Luis
authors.forename: David A
authors.initials: DA
authors.lastname: Russell
authors.forename: Francisco
authors.initials: F
authors.lastname: Galindo
mesh_terms: D000818:Animals; D000880:Anthraquinones / Q000737:chemistry*; D002460:Cell Line; D005456:Fluorescent Dyes / Q000737:chemistry; D008264:Macrophages / Q000378:metabolism; D051379:Mice; D018613:Microscopy, Confocal; D009569:Nitric Oxide / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry
chemical_list: D000880:Anthraquinones; D005456:Fluorescent Dyes; D009569:Nitric Oxide; C118201:1,2-diaminoanthraquinone; D010100:Oxygen