Quantitative assessment of tyrosine nitration of manganese superoxide dismutase in angiotensin II-infused rat kidney

2003 ◽  
Vol 285 (4) ◽  
pp. H1396-H1403 ◽  
Author(s):  
Wei Guo ◽  
Takeshi Adachi ◽  
Reiko Matsui ◽  
Shanqin Xu ◽  
Bingbing Jiang ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Angiotensin Ii ◽  
Western Blotting ◽  
Manganese Superoxide Dismutase ◽  
Rat Kidney ◽  
Oxidant Stress ◽  
Uv Detection ◽  
Tyrosine Nitration ◽  
Manganese Superoxide ◽  
Rat Kidneys

Hypertension caused by angiotensin II is characterized by an increase in tissue oxidant stress as evidenced by increased quantities of reactive oxygen and nitrogen species. Manganese superoxide dismutase (MnSOD) is a key mitochondrial antioxidant enzyme that is inactivated in conditions of oxidant stress by reacting with peroxynitrite to form 3-nitrotyrosine in its active site. The increase in 3-nitrotyrosine content in MnSOD in the kidney of angiotensin II-infused rats was assessed in this study by immunohistochemistry, Western blotting, immunoprecipitation, and HPLC with UV detection (HPLC-UV). MnSOD activity decreased ∼50% in angiotensin II-infused rat kidneys (24 ± 4.6 vs. 11 ± 5.2 U/mg) without a change in protein expression. Immunohistochemical staining showed 3-nitrotyrosine predominantly in distal tubules and collecting duct cells in the angiotensin II-infused rat kidneys. By two-photon microscopy, 3-nitrotyrosine colocalized with MnSOD. Total 3-nitrotyrosine content in kidney homogenates was increased in angiotensin II-infused rat kidney [3.2 ± 1.9 (sham treated) vs. 9.5 ± 2.3 ng/mg protein by HPLC-UV detection]. With tracer amounts of tyrosine-nitrated recombinant MnSOD, the most sensitive technique to detect tyrosine nitration of MnSOD was immunoprecipitation from tissue with anti-MnSOD antibody, followed by detection of 3-nitrotyrosine by Western blotting or HPLC. By HPLC, 3-nitrotyrosine content of kidney MnSOD increased 13-fold after angiotensin II infusion, representing an increase from approximately one-twentieth to one-fifth of the total 3-nitrotyrosine content in sham-treated and angiotensin II-infused rat kidney, respectively. Angiotensin II-induced hypertension is accompanied by increased tyrosine nitration of MnSOD, which, because it inactivates the enzyme, may contribute to increased oxidant stress in the kidney.

scholarly journals Decreases in manganese superoxide dismutase expression and activity contribute to oxidative stress in persistent pulmonary hypertension of the newborn

2012 ◽  
Vol 303 (10) ◽  
pp. L870-L879 ◽  
Author(s):  
Adeleye J. Afolayan ◽  
Annie Eis ◽  
Ru-Jeng Teng ◽  
Ivane Bakhutashvili ◽  
Sushma Kaul ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Nitric Oxide ◽  
Pulmonary Hypertension ◽  
Superoxide Dismutase ◽  
Manganese Superoxide Dismutase ◽  
Pulmonary Arteries ◽  
Tyrosine Nitration ◽  
Enos Expression ◽  
Manganese Superoxide ◽  
Expression And Activity

A rapid increase in the synthesis and release of nitric oxide (NO) facilitates the pulmonary vasodilation that occurs during birth-related transition. Alteration of this transition in persistent pulmonary hypertension of the newborn (PPHN) is associated with impaired function of endothelial nitric oxide synthase (eNOS) and an increase in oxidative stress. We investigated the hypothesis that a decrease in expression and activity of mitochondrial localized manganese superoxide dismutase (MnSOD) in pulmonary artery endothelial cells (PAEC) increases oxidative stress and impairs eNOS function in PPHN. We isolated PAEC and pulmonary arteries from fetal lambs with PPHN induced by prenatal ductus arteriosus ligation or sham ligation (control). We investigated MnSOD expression and activity, tyrosine nitration of MnSOD, and mitochondrial O2− levels in PAEC from control and PPHN lambs. We introduced exogenous MnSOD via an adenoviral vector (ad-MnSOD) transduction into PAEC and pulmonary arteries of PPHN lambs. The effect of ad-MnSOD was investigated on: mitochondrial O2− levels, MnSOD and eNOS expression and activity, intracellular hydrogen peroxide (H2O2) levels, and catalase expression in PAEC. MnSOD mRNA and protein levels and activity were decreased and MnSOD tyrosine nitration was increased in PPHN-PAEC. ad-MnSOD transduction of PPHN-PAEC increased its activity two- to threefold, decreased mitochondrial O2− levels, and increased H2O2 levels and catalase expression. ad-MnSOD transduction improved eNOS expression and function and the relaxation response of PPHN pulmonary arteries. Our observations suggest that decreased MnSOD expression and activity contribute to the endothelial dysfunction observed in PPHN.

scholarly journals Manganese superoxide dismutase (MnSOD) catalyzes NO-dependent tyrosine residue nitration

2005 ◽  
Vol 70 (4) ◽  
pp. 601-608 ◽  
Author(s):  
Srdjan Stojanovic ◽  
Dragana Stanic ◽  
Milan Nikolic ◽  
Smiljana Raicevic ◽  
Mihajlo Spasic ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Manganese Superoxide Dismutase ◽  
Prolonged Exposure ◽  
In Vitro Study ◽  
Enzyme Inactivation ◽  
Tyrosine Nitration ◽  
Tyrosine Residue ◽  
Manganese Superoxide

The peroxynitrite-induced nitration of manganese superoxide dismutase (MnSOD) tyrosine residue, which causes enzyme inactivation, is well established. This led to suggestions that MnSOD nitration and inactivation in vivo, detected in various diseases associated with oxidative stress and overproduction of nitric monoxide (NO), conditions which favor peroxynitrite formation, is also caused by peroxynitrite. However, our previous in vitro study demonstrated that exposure of MnSOD to NO led to NO conversion into nitrosonium (NO+) and nitroxyl (NO?) species, which caused enzyme modifications and inactivation. Here it is reported that MnSOD is tyrosine nitrated upon exposure to NO, as well as that MnSOD nitration contributes to inactivation of the enzyme. Collectively, these observations provide a compelling argument supporting the generation of nitrating species in MnSOD exposed to NO and shed a new light on MnSOD tyrosine nitration and inactivation in vivo. This may represent a novel mechanism by which MnSOD protects cell from deleterious effects associated with overproduction of NO. However, extensive MnSOD modification and inactivation associated with prolonged exposure to NO will amplify the toxic effects caused by increased cell superoxide and NO levels.

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