Am. J. Respir. Cell Mol. Biol.,
Volume 22, Number 1, January, 2000 61-67
Effects of Reactive Oxygen and Nitrogen Metabolites on Eotaxin-Induced
Eosinophil Chemotactic Activity In Vitro
Etsuro
Sato,
Keith L.
Simpson,
Matthew B.
Grisham,
Sekiya
Koyama,
and
Richard A.
Robbins
Research Services, Tucson and Overton Brooks VA Medical Centers, and the Department of Medicine, University of
Arizona, Tucson, Arizona; Department of Molecular and Cellular Physiology, LSU Medical Center, Shreveport, Louisiana;
and The First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan
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 B4 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.
