کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8271579 | 1534981 | 2013 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Mechanisms for cellular NO oxidation and nitrite formation in lung epithelial cells
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کلمات کلیدی
NOAODQS-nitrosothiolSNOCeruloplasminPPDIFN-γIL-1βiNOSCOX-2DETA NONOatep-phenylenediaminenitric oxide analyzerLPSdiethylenetriamine NONOateXanthine oxidase - زانتین اکسیدازNO+ - NO +siRNA - siRNAaldehyde oxidase - آلدئید اکسیدازinterferon-γ - اینترفرون-γInterleukin-1β - اینترلوکین-1βtumor necrosis factor-α - تومور نکروز عامل αHuman lung epithelial cells - سلول های اپیتلیال ریه انسانinducible nitric oxide synthase - سنتاز اکسید نیتریک القاییsulfite oxidase - سولفیت اکسیدازcyclooxygenase 2 - سیکلوکوکسیژناز 2TNF-α - فاکتور نکروز توموری آلفاlipopolysaccharide - لیپوپلی ساکاریدNitrite - نیتریتNitric oxide - نیتریک اکسیدHemoglobin - هموگلوبینHypoxia - هیپوکسیNitrosonium cation - کاتیون نیتروسونیم
موضوعات مرتبط
علوم زیستی و بیوفناوری
بیوشیمی، ژنتیک و زیست شناسی مولکولی
سالمندی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Airway lining fluid contains relatively high concentrations of nitrite, and arterial blood levels of nitrite are higher than venous levels, suggesting the lung epithelium may represent an important source of nitrite in vivo. To investigate whether lung epithelial cells possess the ability to convert NO to nitrite by oxidation, and the effect of oxygen reactions on nitrite formation, the NO donor DETA NONOate was incubated with or without A549 cells or primary human bronchial epithelial (HBE) cells for 24 h under normoxic (21% O2) and hypoxic (1% O2) conditions. Nitrite production was significantly increased under all conditions in the presence of A549 or HBE cells, suggesting that both A549 and HBE cells have the capacity to oxidize NO to nitrite even under low-oxygen conditions. The addition of oxyhemoglobin to the A549 cell medium decreased the production of nitrite, consistent with NO scavenging limiting nitrite formation. Heat-denatured A549 cells produced much lower nitrite and nitrate, suggesting an enzymatic activity is required. This NO oxidation activity was highest in membrane-bound proteins with molecular size <100Â kDa. In addition, 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one and cyanide inhibited formation of nitrite in A549 cells. It has been shown that ceruloplasmin (Cp) possesses an NO oxidase and nitrite synthase activity in plasma based on NO oxidation to nitrosonium cation. We observed that Cp is expressed intracellularly in lung epithelial A549 cells and secreted into the medium under basal conditions and during cytokine stimulation. However, an analysis of Cp expression level and activity measured via p-phenylenediamine oxidase activity assay revealed very low activity compared with plasma, suggesting that there is insufficient Cp to contribute to detectable NO oxidation to nitrite in A549 cells. Additionally, Cp levels were knocked down using siRNA by more than 75% in A549 cells, with no significant change in either nitrite or cellular S-nitrosothiol formation compared to scrambled siRNA control under basal conditions or cytokine stimulation. These data suggest that lung epithelial cells possess NO oxidase activity, which is enhanced in cell-membrane-associated proteins and not regulated by intracellular or secreted Cp, indicating that alternative NO oxidases determine hypoxic and normoxic nitrite formation from NO in human lung epithelial cells.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Free Radical Biology and Medicine - Volume 61, August 2013, Pages 428-437
Journal: Free Radical Biology and Medicine - Volume 61, August 2013, Pages 428-437
نویسندگان
Xue-Jun Zhao, Ling Wang, Sruti Shiva, Jesus Tejero, Mike M. Myerburg, Jun Wang, Sam Frizzell, Mark T. Gladwin,