title: Characterization of a fluorescent probe for imaging nitric oxide.
abstract: Nitric oxide (NO), a potent vasodilator and anti-atherogenic molecule, is synthesized in various cell types, including vascular endothelial cells (ECs). The biological importance of NO enforces the need to develop and characterize specific and sensitive probes. To date, several fluorophores, chromophores and colorimetric techniques have been developed to detect NO or its metabolites (NO(2) and NO(3)) in biological fluids, viable cells or cell lysates.
  
  
  
  Recently, a novel probe (NO(550)) has been developed and reported to detect NO in solutions and in primary astrocytes and neuronal cells with a fluorescence signal arising from a nonfluorescent background.
  
  
  
  Here, we report further characterization of this probe by optimizing conditions for the detection and imaging of NO products in primary vascular ECs, fibroblasts, and embryonic stem cell- and induced pluripotent stem cell-derived ECs in the absence and presence of pharmacological agents that modulate NO levels. In addition, we studied the stability of this probe in cells over time and evaluated its compartmentalization in reference to organelle-labeling dyes. Finally, we synthesized an inherently fluorescent diazo ring compound (AZO(550)) that is expected to form when the nonfluorescent NO(550) reacts with cellular NO, and compared its cellular distribution with that of NO(550).
  
  
  
  NO(550) is a promising agent for imaging NO at baseline and in response to pharmacological agents that modulate its levels.
authors: Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, Tex., USA.
authors: Yohannes T
authors: YT
authors: Ghebremariam
authors: Ngan F
authors: NF
authors: Huang
authors: Swetha
authors: S
authors: Kambhampati Thiruvengadam
authors: Katharina S
authors: KS
authors: Volz
authors: Gururaj G
authors: GG
authors: Joshi
authors: Eric V
authors: EV
authors: Anslyn
authors: John P
authors: JP
authors: Cooke
mesh_terms: D002478:Cells, Cultured; D053595:Embryonic Stem Cells / Q000187:drug effects / Q000378:metabolism; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D005452:Fluoresceins / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism* / Q000633:toxicity; D006801:Humans; D007700:Kinetics; D008856:Microscopy, Fluorescence; D057054:Molecular Imaging / Q000379:methods*; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D039904:Pluripotent Stem Cells / Q000187:drug effects / Q000378:metabolism
chemical_list: C503301:4-amino-5-methylamino-2',7'-difluorofluorescein diacetate; D004791:Enzyme Inhibitors; D005452:Fluoresceins; D005456:Fluorescent Dyes; D020030:Nitric Oxide Donors; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase