3-nitrotyrosine and sodium-bisulfide

Age-related fibrosis is attenuated by aerobic exercise; however, little is known concerning the underlying molecular mechanism. To address this question, aged rats were given moderate-intensity exercise for 12 weeks. After exercise in aged rats, hydrogen sulfide levels in plasma and heart increased 39.8% and 90.9%, respectively. Exercise upregulated expression of cystathionine γ-lyase and 3-mercaptopyruvate sulfurtransferase in heart of aged rats. Furthermore, aged rats were given moderate-intensity exercise for 12 weeks or treated with NaHS (intraperitoneal injection of 0.1 mL/kg per day of 0.28 mol/L NaHS). After exercise in aged rats, Masson-trichrome staining area decreased 34.8% and myocardial hydroxyproline levels decreased 29.6%. Exercise downregulated expression of collagen-I and α- smooth muscle actin in heart of aged rats. Exercise in aged rats reduced malondialdehyde levels in plasma and heart and 3-nitrotyrosine in heart. Exercise in aged rats reduced mRNA and protein expression of C/EBP homologous protein, glucose regulated protein 78, and X-box protein 1. Exercise also reduced mRNA and protein expression of interleukin 6 and monocyte chemotactic protein 1and suppressed activation of c-Jun N-terminal kinase in aging heart. Similar effects were demonstrated in aged rats treated with NaHS. Collectively, exercise restored bioavailability of hydrogen sulfide in the heart of aged rats, which partly explained the benefits of exercise against myocardial fibrosis of aged population.

Topics: Aging; Animals; Chemokine CCL2; Endoplasmic Reticulum Stress; Fibrosis; Heart; Hydrogen Sulfide; Hydroxyproline; Interleukin-6; Male; Malondialdehyde; Myocardium; Physical Conditioning, Animal; Rats; Sulfides; Tyrosine

Hydrogen sulfide (H₂S) is an endogenous gaseous mediator affecting many physiological and pathophysiological conditions. Enhanced expression of H2S and reactive nitrogen/oxygen species (RNS/ROS) during inflammation alters cellular excitability via modulation of ion channel function. Sulfhydration of cysteine residues and tyrosine nitration are the posttranslational modifications induced by H₂S and RNS, respectively. The objective of this study was to define the interaction between tyrosine nitration and cysteine sulfhydration within the ATP-sensitive K(+) (KATP) channel complex, a significant target in experimental colitis. A modified biotin switch assay was performed to determine sulfhydration of the KATP channel subunits, Kir6.1, sulphonylurea 2B (SUR2B), and nitrotyrosine measured by immunoblot. NaHS (a donor of H₂S) significantly enhanced sulfhydration of SUR2B but not Kir6.1 subunit. 3-Morpholinosydnonimine (SIN-1) (a donor of peroxynitrite) induced nitration of Kir6.1 subunit but not SUR2B. Pretreatment with NaHS reduced the nitration of Kir6.1 by SIN-1 in Chinese hamster ovary cells cotransfected with the two subunits, as well as in enteric glia. Two specific mutations within SUR2B, C24S, and C1455S prevented sulfhydration by NaHS, and these mutations prevented NaHS-induced reduction in tyrosine nitration of Kir6.1. NaHS also reversed peroxynitrite-induced inhibition of smooth muscle contraction. These studies suggest that posttranslational modifications of the two subunits of the KATP channel interact to alter channel function. The studies described herein demonstrate a unique mechanism by which sulfhydration of one subunit modifies tyrosine nitration of another subunit within the same channel complex. This interaction provides a mechanistic insight on the protective effects of H₂S in inflammation.

Topics: Animals; Calcium Chloride; CHO Cells; Cricetulus; Cysteine; Dose-Response Relationship, Drug; Ileum; KATP Channels; Mice; Molsidomine; Muscle Contraction; Muscle, Smooth; Mutation; Peroxynitrous Acid; Protein Processing, Post-Translational; Signal Transduction; Sulfides; Sulfonylurea Receptors; Transfection; Tyrosine

Recent studies show that endogenous hydrogen sulfide (H(2)S) plays an anti-inflammatory role in the pathogenesis of airway inflammation. This study investigated whether exogenous H(2)S may counteract oxidative stress-mediated lung damage in allergic mice. Female BALB/c mice previously sensitized with ovalbumin (OVA) were treated with sodium hydrosulfide (NaHS) 30 min before OVA challenge. Forty eight hours after antigen-challenge, the mice were killed and leukocyte counting as well as nitrite plus nitrate concentrations were determined in the bronchoalveolar lavage fluid, and lung tissue was analysed for nitric oxide synthase (NOS) activity, iNOS expression, superoxide dismutase (SOD), catalase, glutathione reductase (GR) and glutathione peroxidase (GPx) activities, thiobarbituric acid reactive species and 3-nitrotyrosine containing proteins (3-NT). Pre-treatment of OVA-sensitized mice with NaHS resulted in significant reduction of both eosinophil and neutrophil migration to the lungs, and prevented the elevation of iNOS expression and activity observed in the lungs from the untreated allergic mice, although it did not affect 3-NT. NaHS treatment also abolished the increased lipid peroxidation present in the allergic mouse lungs and increased SOD, GPx and GR enzyme activities. These results show, for the first time, that the beneficial in vivo effects of the H(2)S-donor NaHS on allergic airway inflammation involve its inhibitory action on leukocyte recruitment and the prevention of lung damage by increasing endogenous antioxidant defenses. Thus, exogenous administration of H(2)S donors may be beneficial in reducing the deleterius impact of allergic pulmonary disease, and might represent an additional class of pharmacological agents for treatment of chronic pulmonary diseases.

Topics: Animals; Catalase; Female; Glutathione Peroxidase; Glutathione Reductase; Hydrogen Sulfide; Hypersensitivity; Leukocytes; Lung; Mice; Mice, Inbred BALB C; Nitric Oxide Synthase; Oxidative Stress; Sulfides; Superoxide Dismutase; Thiobarbiturates; Tyrosine

Hydrogen sulfide (H2S) is a novel gaseous mediator produced by cystathionine-beta-synthase and cystathionine-gamma-lyase in the cardiovascular system, including the heart. Using a rat model of regional myocardial ischemia/reperfusion, we investigated the effects of an H2S donor (sodium hydrogen sulfide [NaHS]) on the infarct size and apoptosis caused by ischemia (25 min) and reperfusion (2 h). Furthermore, we investigated the potential mechanism(s) of the cardioprotective effect(s) afforded by NaHS. Specifically, we demonstrate that NaHS (1) attenuates the increase in caspase 9 activity observed in cardiac myocytes isolated from the area at risk (AAR) of hearts subjected in vivo to regional myocardial I/R and (2) ameliorates the decrease in expression of Bcl-2 within the AAR obtained from rat hearts subjected to regional myocardial I/R. The cardioprotective effects of NaHS were abolished by 5-hydroxydeconoate, a putative mitochondrial adenosine triphosphate-sensitive potassium channel blocker. Furthermore, NaHS attenuated the increase in the I/R-induced (1) phosphorylation of p38 mitogen-activated protein kinase and Jun N-terminal kinase, (2) translocation from the cytosol to the nucleus of the p65 subunit of nuclear factor-kappaB, (3) intercellular adhesion molecule 1 expression, (4) polymorphonuclear leukocyte accumulation, (5) myeloperoxidase activity, (6) malondialdehyde levels, and (7) nitrotyrosine staining determined in the AAR obtained from rat hearts subjected to regional myocardial I/R. In conclusion, we demonstrate that the cardioprotective effect of NaHS is secondary to a combination of antiapoptotic and anti-inflammatory effects. The antiapoptotic effect of NaHS may be in part due to the opening of the putative mitochondrial adenosine triphosphate-sensitive potassium channels.

Topics: Active Transport, Cell Nucleus; Animals; Anti-Arrhythmia Agents; Anti-Inflammatory Agents, Non-Steroidal; Apoptosis; Cardiotonic Agents; Cell Nucleus; Decanoic Acids; Disease Models, Animal; Drug Antagonism; Hydroxy Acids; Male; Malondialdehyde; Muscle Proteins; Myocardial Reperfusion Injury; Neutrophils; Phosphorylation; Rats; Rats, Wistar; Sulfides; Tyrosine