Abstract 223: S-glutathiolation Uncouples Endothelial Nitric Oxide (NO) Synthase, Switching Enzyme from NO to Superoxide Production

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Chun-An Chen ◽  
Lawrence J Druhan ◽  
Tse-Yao Wang ◽  
Yeong-Renn Chen ◽  
Jay L Zweier

Overproduction of superoxide (•O 2 − ) and •O 2 − -derived oxidants increases cellular oxidative stress. This can lead to cell death, via apoptosis or necrosis. An important response of protein thiols to oxidative stress is reversible formation of protein mixed disulfides via S-glutathiolation. This redox based protein modification is thought to play an important role as an adaptive response to oxidative injury in cells, or alternatively in controlling cellular signaling in a manner similar to phosphorylation. Protein S-glutathiolation is increased in the post-ischemic heart. Human eNOS, which is of critical importance in maintaining cardiovascular function, contains 29 cysteinyl residues. To investigate the effects of S-glutathiolation on the regulation of eNOS function and its relation to cardiovascular diseases, eNOS functional alterations induced by S-glutathiolation were studied. Additionally, LC/MS/MS was used to determine the precise residues of eNOS involved in this redox-dependent thiol modification. S-glutatiolation significantly reduced NO production from heNOS, with a 63% decrease induced by incubation with 2 mM GSSG in vitro . This process was reversible by addition of DTT. Alkylation of the cysteinyl residues with N-ethylmaleimide (NEM) completely inhibited NO production. S-glutathiolation of an uncoupled heNOS increased •O 2 − generation (> 70%), and this increase was only partially blocked by L-NAME, implicating the reductase site as the source for the increased •O 2 − generation. When the cysteinyl residues were all alkylated with NEM, the •O 2 − generation from eNOS was dramatically increased (+2.4-fold), and this increase was not inhibited by L-NAME. We have identified three cysteine residues, C 382 , C 689 and C 908 as sights of S-glutathiolation in heNOS, all three of which are conserved in all known mammalian eNOS enzymes. Therefore, cysteinyl residues are critical for the regulation of eNOS coupling, and S-glutatiolation of specific residues switches eNOS from an NO producing to a •O 2 − generating enzyme, by inducing electron leakage from the reductase domain. As such, S-glutathiolation provides a novel mechanism for the regulation of heNOS, defining a unique pathway for the redox regulation of cardiovascular function. This research has received full or partial funding support from the American Heart Association, AHA Great Rivers Affiliate (Delaware, Kentucky, Ohio, Pennsylvania & West Virginia).

Author(s):  
Pullaiah P. ◽  
Suchitra M. M. ◽  
Siddhartha Kumar B.

Background: Oxidative stress (OS) has an important role in the pathogenesis and progression of rheumatoid arthritis (RA). OS causes protein modification, thereby impairing the biological functions of the protein. This study was conducted to assess the oxidatively modified protein as protein carbonyl content and the antioxidant status as protein thiols, and to study the association between protein carbonyls and protein thiols in RA.Methods: Newly diagnosed RA patients who were not taking any disease modifying anti-rheumatic drugs were included into the study group (n=45) along with age and sex matched healthy controls (n=45). Serum protein carbonyl content and protein thiols were estimated.Results: Elevated protein carbonyl content and decreased protein thiol levels (p<0.001) were observed in RA. A significant negative correlation was observed between protein carbonyl content and protein thiol levels (p<0.001).Conclusions: Oxidative stress in RA is evidenced by enhanced protein oxidation and decreased antioxidant protein thiol levels. Decreased protein thiols may also reflect protein modifications leading to compromise in the antioxidant properties. This oxidant and antioxidant imbalance needs to be addressed by therapeutic interventions to prevent disease progression.


2015 ◽  
Vol 11 (3) ◽  
pp. 923-929 ◽  
Author(s):  
Xiaowei Zhao ◽  
Qiao Ning ◽  
Meiyu Ai ◽  
Haiting Chai ◽  
Minghao Yin

S-Glutathionylation is a reversible protein post-translational modification, which generates mixed disulfides between glutathione (GSH) and cysteine residues, playing an important role in regulating protein stability, activity, and redox regulation.


2007 ◽  
Vol 292 (5) ◽  
pp. F1404-F1410 ◽  
Author(s):  
You-Lin Tain ◽  
Gary Freshour ◽  
Anna Dikalova ◽  
Kathy Griendling ◽  
Chris Baylis

Chronic kidney disease is accompanied by nitric oxide (NO) deficiency and oxidative stress, which contribute to progression. We investigated whether the antioxidant vitamin E could preserve renal function and NO bioavailability and reduce oxidative stress in the 5/6th nephrectomy (NX) rat model. We studied the following three groups of male Sprague-Dawley rats: sham ( n = 6), 5/6 NX control ( n = 6), and 5/6 NX treated with vitamin E (5,000 IU/kg chow; n = 5). The 5/6 NX group showed increased severity of glomerulosclerosis vs. sham, and this was ameliorated by vitamin E therapy. Both 5/6 NX groups showed similar elevations in plasma creatinine and proteinuria and decreased 24-h creatinine clearance compared with sham. There was increased NADPH-dependent superoxide production in 5/6 NX rats vs. sham that was prevented by vitamin E. Total NO production was similarly reduced in both 5/6 NX groups. There was unchanged abundance of endothelial nitric oxide synthesis (NOS) in renal cortex and medulla and neuronal (n) NOS in medulla. However, in kidney cortex, 5/6 NX rats had lower nNOS abundance than sham, which was restored by vitamin E. An increased plasma asymmetric dimethylarginine occurred with 5/6 NX associated with decreased renal dimethylarginine dimethylaminohydrolase activity and increased type 1 protein arginine methyltransferase expression.


1999 ◽  
Vol 19 (4) ◽  
pp. 2650-2656 ◽  
Author(s):  
Chris M. Grant ◽  
Kathryn A. Quinn ◽  
Ian W. Dawes

ABSTRACT The irreversible oxidation of cysteine residues can be prevented by protein S-thiolation, in which protein -SH groups form mixed disulfides with low-molecular-weight thiols such as glutathione. We report here the identification of glyceraldehyde-3-phosphate dehydrogenase as the major target of protein S-thiolation following treatment with hydrogen peroxide in the yeastSaccharomyces cerevisiae. Our studies reveal that this process is tightly regulated, since, surprisingly, despite a high degree of sequence homology (98% similarity and 96% identity), the Tdh3 but not the Tdh2 isoenzyme was S-thiolated. The glyceraldehyde-3-phosphate dehydrogenase enzyme activity of both the Tdh2 and Tdh3 isoenzymes was decreased following exposure to H2O2, but only Tdh3 activity was restored within a 2-h recovery period. This indicates that the inhibition of the S-thiolated Tdh3 polypeptide was readily reversible. Moreover, mutants lacking TDH3 were sensitive to a challenge with a lethal dose of H2O2, indicating that the S-thiolated Tdh3 polypeptide is required for survival during conditions of oxidative stress. In contrast, a requirement for the nonthiolated Tdh2 polypeptide was found during exposure to continuous low levels of oxidants, conditions where the Tdh3 polypeptide would be S-thiolated and hence inactivated. We propose a model in which both enzymes are required during conditions of oxidative stress but play complementary roles depending on their ability to undergo S-thiolation.


Author(s):  
L. Madden Brewster ◽  
Anthony R. Bain ◽  
Vinicius P. Pacheco Garcia ◽  
Hannah K Fandl ◽  
Rachel Stone ◽  
...  

High altitude-related excessive erythrocytosis (EE) is associated with increased cardiovascular risk. The experimental aim of this study was to determine the effects of microvesicles isolated from Andean highlanders with EE on endothelial cell inflammation, oxidative stress, apoptosis and nitric oxide (NO) production.Twenty-six male residents of Cerro de Pasco, Peru (4,340 m) were studied: 12 highlanders without EE (age: 40±4 yr; BMI: 26.4±1.7; Hb: 17.4±0.5 g/dL, SpO2: 86.9±1.0%) and 14 highlanders with EE (43±4 yr; 26.2±0.9; 24.4±0.4 g/dL;79.7±1.6%). Microvesicles were isolated, enumerated and collected from plasma by flow cytometry. Human umbilical vein endothelial cells were cultured and treated with microvesicles from highlanders without and with EE. Microvesicles from highlanders with EE induced significantly higher release of interleukin (IL)-6 (89.8±2.7 vs 77.1±1.9 pg/mL) and IL-8 (62.0±2.7 vs 53.3±2.2 pg/mL) compared with microvesicles from healthy highlanders. Although intracellular expression of total NF-kB p65 (65.3+6.0 vs 74.9+7.8.9 AU) was not significantly affected, microvesicles from highlanders with EE resulted in ~25% higher (P<0.05) expression of p-NF-kB p65 (173.6+14.3 vs 132.8+12.2 AU) in cells treated with microvesicles from highlanders with EE. Cell reactive oxygen species production was significantly higher (76.4.7±5.4 vs 56.7±1.7 % of control) and endothelial nitric oxide synthase (p-eNOS) activation (231.3±15.5 vs 286.6±23.0 AU) and NO production (8.3±0.6 vs 10.7±0.7 μM/L) significantly lower in cells treated with microvesicles from highlanders with vs without EE. Cell apoptotic susceptibility was not significantly affected by EE-related microvesicles.Circulating microvesicles from Andean highlanders with EE increase endothelial cell inflammation and oxidative stress and reduced NO production.


2020 ◽  
Vol 17 (3) ◽  
pp. 172-179
Author(s):  
Chien-Yi Wu ◽  
Wun-Rong Lin ◽  
Cherng-Jye Jeng ◽  
Chien-Hsing Wu ◽  
Bin Huang

Background: Arecoline is known as a carcinogenic toxicant. The refreshment effect of arecoline is mainly due to the increase in vasodilation and blood flow. This is essential to understand whether arecoline can induce the production of Nitric Oxide (NO•) and regulate the subsequent protein S-nitrosylation in Endothelial Cells (ECs). Objective: The present study is focused on the promotion effect of arecoline in NO• production and the subsequent regulation of S-nitrosoproteome. Method: The phosphorylation of endothelial nitric oxide synthase serine 1177 residue (peNOSSer1177) was investigated by western blot. By using a specific FA-OMe fluorescent probe, the NO• molecules could be observed by fluorescent microscopy or flow cytometry. S-nitrosylated proteins were purified by biotin switch and then subjected to the Isobaric Tag for Relative and Absolute Quantitation (iTRAQ)-labeled shotgun proteomic analysis. Results: Our study reveals that a lower concentration of arecoline can increase the phosphorylation of peNOSSer1177. Pretreatment of NG-nitro-L-arginine methyl ester (L-NAME) indicated that arecolineinduced NO• production was mediated by e-NOS. We identified 224 proteins with up-regulated S-nitrosylation and 159 proteins with down-regulated S-nitrosylation. The NO• binding sites of seven representative S-nitrosoproteins were illustrated. The effect of arecoline on the S-nitrosylation of HSP60 chaperonin and calnexin was verified. Conclusion: Our experimental results proved that a lower concentration of arecoline could modulate the production of NO• and the subsequent protein S-nitrosylation. Therefore, it is worthy for further investigation and discussion if these S-nitrosoproteomes are important in maintaining endothelium homeostasis.


2020 ◽  
Vol 21 (21) ◽  
pp. 8113 ◽  
Author(s):  
Aysenur Musaogullari ◽  
Yuh-Cherng Chai

S-glutathionylation, the post-translational modification forming mixed disulfides between protein reactive thiols and glutathione, regulates redox-based signaling events in the cell and serves as a protective mechanism against oxidative damage. S-glutathionylation alters protein function, interactions, and localization across physiological processes, and its aberrant function is implicated in various human diseases. In this review, we discuss the current understanding of the molecular mechanisms of S-glutathionylation and describe the changing levels of expression of S-glutathionylation in the context of aging, cancer, cardiovascular, and liver diseases.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Peipei Meng ◽  
Rui Yang ◽  
Fenjun Jiang ◽  
Jianbo Guo ◽  
Xinyu Lu ◽  
...  

Endothelial dysfunction, induced by oxidative stress, is an essential factor affecting cardiovascular disease. Uncoupling of endothelial nitric oxide synthase (eNOS) leads to a decrease in nitric oxide (NO) production, an increase in reactive oxygen species (ROS) production, NO consumption, and NO synthesis. As a main active ingredient of astragalus, astragaloside IV can reduce the apoptosis of endothelial cells during oxidative stress. This review is aimed at exploring the mechanism of astragaloside IV in improving oxidative stress-mediated endothelial dysfunction relevant to cardiovascular diseases. The findings showed that the astragaloside IV can prevent or reverse the uncoupling of eNOS, increase eNOS and NO, and enhance several activating enzymes to activate the antioxidant system. In-depth validation and quantitative experiments still need to be implemented.


2005 ◽  
Vol 33 (6) ◽  
pp. 1378-1381 ◽  
Author(s):  
P. Ghezzi

Protein cysteines can undergo various forms of oxidation, some of them reversible (disulphide formation, glutathionylation and S-nitrosylation). While in the past these were viewed as protein damage in the context of oxidative stress, there is growing interest in oxidoreduction of protein thiols/disulphides as a regulatory mechanism. This review discusses the evolution of the concept of redox regulation from that of oxidative stress and the redox state of protein cysteines in different cellular compartments.


2021 ◽  
Vol 22 (19) ◽  
pp. 10713
Author(s):  
Briana K. Shimada ◽  
Naghum Alfulaij ◽  
Lucia A. Seale

Selenium (Se) is an essential trace element that is necessary for various metabolic processes, including protection against oxidative stress, and proper cardiovascular function. The role of Se in cardiovascular health is generally agreed upon to be essential yet not much has been defined in terms of specific functions. Se deficiency was first associated with Keshan’s Disease, an endemic disease characterized by cardiomyopathy and heart failure. Since then, Se deficiency has been associated with multiple cardiovascular diseases, including myocardial infarction, heart failure, coronary heart disease, and atherosclerosis. Se, through its incorporation into selenoproteins, is vital to maintain optimal cardiovascular health, as selenoproteins are involved in numerous crucial processes, including oxidative stress, redox regulation, thyroid hormone metabolism, and calcium flux, and inadequate Se may disrupt these processes. The present review aims to highlight the importance of Se in cardiovascular health, provide updated information on specific selenoproteins that are prominent for proper cardiovascular function, including how these proteins interact with microRNAs, and discuss the possibility of Se as a potential complemental therapy for prevention or treatment of cardiovascular disease.


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