title: Effects of reactive oxygen and nitrogen metabolites on eotaxin-induced eosinophil chemotactic activity in vitro.
abstract: Peroxynitrite, an oxidant generated by the interaction between superoxide and nitric oxide (NO), has been implicated in the etiology of numerous disease processes. Several studies have shown that peroxynitrite-induced protein nitration may compromise enzyme and protein function. We hypothesized that peroxynitrite may regulate cytokine function during inflammation. To test this hypothesis, the eosinophil chemotactic responses of eotaxin incubated with and without peroxynitrite were evaluated. Peroxynitrite attenuated eotaxin-induced eosinophil chemotactic activity (ECA) in a dose-dependent manner (P < 0.05). The inhibitory effects were not significant on ECA induced by leukotriene B(4) or complement-activated serum incubated with peroxynitrite. The reducing agents deferoxamine and dithiothreitol reversed the ECA inhibition by peroxynitrite, and exogenous L-tyrosine abrogated the inhibition by peroxynitrite. PAPA-NONOate (an NO donor) or a combination of xanthine and xanthine oxidase to generate superoxide did not show an inhibitory effect on ECA induced by eotaxin. In contrast, 3-morpholinosydnonimine, a peroxynitrite generator, caused a concentration-dependent inhibition of ECA by eotaxin. Consistent with its capacity to reduce ECA, peroxynitrite treatment reduced eotaxin binding to eosinophils. Nitrotyrosine was detected in the eotaxin incubated with peroxynitrite. These findings are consistent with nitration of tyrosine by peroxynitrite with subsequent inhibition of eotaxin binding to eosinophils and a reduction in ECA. These data demonstrate that peroxynitrite modulates the eosinophil migration by eotaxin, and suggest that oxidants may play an important role in regulation of eotaxin-induced eosinophil chemotaxis.
authors.affiliation: Research Services, Tucson and Overton Brooks VA Medical Centers, and the Department of Medicine, University of Arizona, Tucson, Arizona 85723, USA.
authors.forename: E
authors.initials: E
authors.lastname: Sato
authors.forename: K L
authors.initials: KL
authors.lastname: Simpson
authors.forename: M B
authors.initials: MB
authors.lastname: Grisham
authors.forename: S
authors.initials: S
authors.lastname: Koyama
authors.forename: R A
authors.initials: RA
authors.lastname: Robbins
mesh_terms: D001665:Binding Sites / Q000187:drug effects; D054413:Chemokine CCL11; D019742:Chemokines, CC; D002631:Chemotactic Factors, Eosinophil / Q000378:metabolism / Q000502:physiology; D002634:Chemotaxis, Leukocyte / Q000187:drug effects; D016207:Cytokines / Q000378:metabolism / Q000502:physiology*; D004804:Eosinophils / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D006834:Hydrazines / Q000494:pharmacology; D009566:Nitrates / Q000494:pharmacology; D009569:Nitric Oxide / Q000494:pharmacology; D009584:Nitrogen / Q000378:metabolism / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism / Q000502:physiology*; D019163:Reducing Agents / Q000494:pharmacology; D013481:Superoxides / Q000378:metabolism / Q000494:pharmacology; D019820:Xanthine / Q000378:metabolism; D014969:Xanthine Oxidase / Q000378:metabolism
chemical_list: C515456:CCL11 protein, human; D054413:Chemokine CCL11; D019742:Chemokines, CC; D002631:Chemotactic Factors, Eosinophil; D016207:Cytokines; D006834:Hydrazines; D009566:Nitrates; C112653:PAPA NONOate; D017382:Reactive Oxygen Species; D019163:Reducing Agents; D013481:Superoxides; D019820:Xanthine; C039642:peroxynitric acid; D009569:Nitric Oxide; D014969:Xanthine Oxidase; D009584:Nitrogen