201
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Stecyk JAW, Skovgaard N, Nilsson GE, Wang T. Vasoactivity of hydrogen sulfide in normoxic and anoxic turtles (Trachemys scripta). Am J Physiol Regul Integr Comp Physiol 2010; 298:R1225-39. [DOI: 10.1152/ajpregu.00521.2009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Systemic vascular resistance ( Rsys) of freshwater turtles increases substantially during anoxia, but the underlying mechanisms are not fully understood. We investigated whether hydrogen sulfide (H2S), an endogenously produced metabolite believed to be an O2 sensor/transducer of vasomotor tone, contributes to the increased Rsys of anoxic red-eared slider turtles ( Trachemys scripta ). Vascular infusion of the H2S donor NaHS in anesthetized turtles at 21°C and fully recovered normoxic turtles at 5°C and 21°C revealed H2S to be a potent vasoconstrictor of the systemic circulation. Likewise, wire myography of isolated turtle mesenteric and pulmonary arteries demonstrated H2S to mediate an anoxia-induced constriction. Intriguingly, however, NaHS did not exert vasoconstrictory effects during anoxia (6 h at 21°C; 14 days at 5°C) when plasma H2S concentration, estimated from the colorimetric measurement of plasma acid-labile sulfide concentration, likely increased by ∼3- and 4-fold during anoxia at 21°C, and 5°C, respectively. Yet, blockade of endogenous H2S production by DL-propargylglycine or hydroxylamine (0.44 mmol/kg) partially reversed the decreased systemic conductance ( Gsys) exhibited by 5°C anoxic turtles. These findings suggest that the signal transduction pathway of H2S-mediated vasoactivity is either maximally activated in the systemic circulation of anoxic turtles and/or that it is oxygen dependent.
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Affiliation(s)
- Jonathan A. W. Stecyk
- Physiology Programme, Department of Molecular Biosciences, University of Oslo, Oslo, Norway; and
| | - Nini Skovgaard
- Zoophysiology, Department of Biological Sciences, Aarhus University, Aarhus, Denmark
| | - Göran E. Nilsson
- Physiology Programme, Department of Molecular Biosciences, University of Oslo, Oslo, Norway; and
| | - Tobias Wang
- Zoophysiology, Department of Biological Sciences, Aarhus University, Aarhus, Denmark
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202
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Wallace JL. Physiological and pathophysiological roles of hydrogen sulfide in the gastrointestinal tract. Antioxid Redox Signal 2010; 12:1125-33. [PMID: 19769457 DOI: 10.1089/ars.2009.2900] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Like nitric oxide and carbon monoxide, hydrogen sulfide has historically been recognized as an industrial pollutant, but in recent years, it has been shown to be an important mediator of many physiological processes. Hydrogen sulfide contributes to the maintenance of gastrointestinal mucosal defense and repair. It also exerts many antiinflammatory effects, including inhibition of leukocyte adherence to the vascular endothelium and leukocyte migration to sites of inflammation. Conversely, inhibition of endogenous hydrogen sulfide synthesis leads to a loss of mucosal integrity and to an increase in mucosal inflammation. Hydrogen sulfide therefore appears to have overlapping actions with nitric oxide and prostaglandins in terms of modulating mucosal defense and resolution of inflammation. Recent evidence suggests that these properties of hydrogen sulfide can be exploited in the design of novel therapies for ulcerative and inflammatory diseases of the gastrointestinal tract.
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Affiliation(s)
- John L Wallace
- Farncombe Family Institute for Digestive Health Research, Department of Medicine, McMaster University, 1200 Main Street West, Hamilton, Ontario, Canada.
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203
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Ekundi-Valentim E, Santos KT, Camargo EA, Denadai-Souza A, Teixeira SA, Zanoni CI, Grant AD, Wallace JL, Muscará MN, Costa SK. Differing effects of exogenous and endogenous hydrogen sulphide in carrageenan-induced knee joint synovitis in the rat. Br J Pharmacol 2010; 159:1463-74. [PMID: 20136840 PMCID: PMC2850403 DOI: 10.1111/j.1476-5381.2010.00640.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 11/05/2009] [Accepted: 11/13/2009] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE Recent findings suggest that the noxious gas H(2)S is produced endogenously, and that physiological concentrations of H(2)S are able to modulate pain and inflammation in rodents. This study was undertaken to evaluate the ability of endogenous and exogenous H(2)S to modulate carrageenan-induced synovitis in the rat knee. EXPERIMENTAL APPROACH Synovitis was induced in Wistar rats by intra-articular injection of carrageenan into the knee joint. Sixty minutes prior to carrageenan injection, the rats were pretreated with indomethacin, an inhibitor of H(2)S formation (DL-propargylglycine) or an H(2)S donor [Lawesson's reagent (LR)]. KEY RESULTS Injection of carrageenan evoked knee inflammation, pain as characterized by impaired gait, secondary tactile allodynia of the ipsilateral hindpaw, joint swelling, histological changes, inflammatory cell infiltration, increased synovial myeloperoxidase, protein nitrotyrosine residues, inducible NOS (iNOS) activity and NO production. Pretreatment with LR or indomethacin significantly attenuated the pain responses, and all the inflammatory and biochemical changes, except for the increased iNOS activity, NO production and 3-NT. Propargylglycine pretreatment potentiated synovial iNOS activity (and NO production), and enhanced macrophage infiltration, but had no effect on other inflammatory parameters. CONCLUSIONS AND IMPLICATIONS Whereas exogenous H(2)S delivered to the knee joint can produce a significant anti-inflammatory and anti-nociceptive effect, locally produced H(2)S exerts little immunomodulatory effect. These data further support the development and use of H(2)S donors as potential alternatives (or complementary therapies) to the available anti-inflammatory compounds used for treatment of joint inflammation or relief of its symptoms.
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Affiliation(s)
- E Ekundi-Valentim
- Department of Pharmacology, Institute of Biomedical Sciences, University of São PauloSão Paulo, SP, Brazil
| | - KT Santos
- Department of Pharmacology, Institute of Biomedical Sciences, University of São PauloSão Paulo, SP, Brazil
| | - EA Camargo
- Department of Pharmacology, Institute of Biomedical Sciences, University of São PauloSão Paulo, SP, Brazil
- Department of Physiology, Federal University of SergipeAracaju-SE, Brazil
| | - A Denadai-Souza
- Department of Pharmacology, Institute of Biomedical Sciences, University of São PauloSão Paulo, SP, Brazil
| | - SA Teixeira
- Department of Pharmacology, Institute of Biomedical Sciences, University of São PauloSão Paulo, SP, Brazil
| | - CI Zanoni
- Department of Pharmacology, Institute of Biomedical Sciences, University of São PauloSão Paulo, SP, Brazil
| | - AD Grant
- Wolfson Centre for Age-related Diseases, King's CollegeLondon, UK
| | - JL Wallace
- Farncombe Institute, Department of Medicine, McMaster UniversityHamilton, ON, Canada
| | - MN Muscará
- Department of Pharmacology, Institute of Biomedical Sciences, University of São PauloSão Paulo, SP, Brazil
| | - SK Costa
- Department of Pharmacology, Institute of Biomedical Sciences, University of São PauloSão Paulo, SP, Brazil
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204
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Zhu XY, Liu SJ, Liu YJ, Wang S, Ni X. Glucocorticoids suppress cystathionine gamma-lyase expression and H2S production in lipopolysaccharide-treated macrophages. Cell Mol Life Sci 2010; 67:1119-32. [PMID: 20063035 PMCID: PMC11115566 DOI: 10.1007/s00018-009-0250-9] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Revised: 11/30/2009] [Accepted: 12/15/2009] [Indexed: 12/31/2022]
Abstract
Hydrogen sulfide (H(2)S) plays an important role in inflammation. We showed that macrophages expressed the H(2)S-forming enzyme cystathionine gamma-lyase (CSE) and produced H(2)S. Lipopolysaccharide (LPS) stimulated the CSE expression and H(2)S production rate. l-cysteine reduced LPS-induced nitric oxide (NO) production. CSE inhibitor blocked the inhibitory effect of l-cysteine. CSE knockdown increased, whereas CSE overexpression decreased LPS-induced NO production. Dexamethasone suppressed LPS-induced CSE expression and the H(2)S production rate as well as NO production. l-arginine increased, whereas N(G)-nitro-l-arginine methyl ester (l-NAME) decreased LPS-induced CSE expression and H(2)S production. Dexamethasone plus l-NAME significantly decreased LPS-induced CSE expression and H(2)S production compared to l-NAME. Our results suggest that macrophages are one of the H(2)S producing sources. H(2)S might exert anti-inflammatory effects by inhibiting NO production. Dexamethasone may directly inhibit CSE expression and H(2)S production, besides the NO-dependent way. Inhibition of H(2)S and NO production may be a mechanism by which glucocorticoids coordinate the balance between pro- and anti-inflammatory mediators during inflammation.
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Affiliation(s)
- Xiao-Yan Zhu
- Department of Physiology, Second Military Medical University, 800 Xiangyin Road, 200433 Shanghai, People’s Republic of China
- Key Laboratory Neurobiology, Ministry of Education, Second Military Medical University, Shanghai, People’s Republic of China
| | - Shu-Juan Liu
- Department of Physiology, Second Military Medical University, 800 Xiangyin Road, 200433 Shanghai, People’s Republic of China
- Key Laboratory Neurobiology, Ministry of Education, Second Military Medical University, Shanghai, People’s Republic of China
| | - Yu-Jian Liu
- Department of Pathophysiology, Second Military Medical University, 200433 Shanghai, People’s Republic of China
| | - Shan Wang
- Department of Physiology, Second Military Medical University, 800 Xiangyin Road, 200433 Shanghai, People’s Republic of China
- Key Laboratory Neurobiology, Ministry of Education, Second Military Medical University, Shanghai, People’s Republic of China
| | - Xin Ni
- Department of Physiology, Second Military Medical University, 800 Xiangyin Road, 200433 Shanghai, People’s Republic of China
- Key Laboratory Neurobiology, Ministry of Education, Second Military Medical University, Shanghai, People’s Republic of China
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205
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Abstract
The gastrointestinal tract (GIT) is a metabolically significant site of sulfur amino acid (SAA) metabolism in the body and metabolises about 20 % of the dietary methionine intake which is mainly transmethylated to homocysteine and trans-sulfurated to cysteine. The GIT accounts for about 25 % of the whole-body transmethylation and trans-sulfuration. In addition, in vivo studies in young pigs indicate that the GIT is a site of net homocysteine release and thus may contribute to the homocysteinaemia. The gut also utilises 25 % of the dietary cysteine intake and the cysteine uptake by the gut represents about 65 % of the splanchnic first-pass uptake. Moreover, we recently showed that SAA deficiency significantly suppresses intestinal mucosal growth and reduces intestinal epithelial cell proliferation, and increases intestinal oxidant stress in piglets. These recent findings indicate that intestinal metabolism of dietary methionine and cysteine is nutritionally important for intestinal mucosal growth. Besides their role in protein synthesis, methionine and cysteine are precursors of important molecules. S-adenosylmethionine, a metabolite of methionine, is the principal biological methyl donor in mammalian cells and a precursor for polyamine synthesis. Cysteine is the rate-limiting amino acid for glutathione synthesis, the major cellular antioxidant in mammals. Further studies are warranted to establish how SAA metabolism regulates gut growth and intestinal function, and contributes to the development of gastrointestinal diseases. The present review discusses the evidence of SAA metabolism in the GIT and its functional and nutritional importance in gut function and diseases.
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206
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Hosgood SA, Nicholson ML. Hydrogen sulphide ameliorates ischaemia-reperfusion injury in an experimental model of non-heart-beating donor kidney transplantation. Br J Surg 2010; 97:202-9. [PMID: 20034052 DOI: 10.1002/bjs.6856] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND : Therapies to alleviate ischaemia-reperfusion (IR) injury have an important role in kidney transplantation. This study used a porcine model of non-heart-beating (NHB) donor kidneys to investigate the effects of hydrogen sulphide on IR injury. METHODS : Porcine kidneys were subjected to 25 min of warm ischaemia and 18 h of cold storage. They were reperfused ex vivo with autologous oxygenated blood to assess renal function. A group treated with hydrogen sulphide (0.5 mmol/l) infused 10 min before and after reperfusion (n = 6) was compared with an untreated control group (n = 7). RESULTS : Hydrogen sulphide significantly improved renal blood flow compared with control values (mean(s.d.) area under the curve (AUC) 614.9(165.5) versus 270.3(86.7) ml per min per 100 g.h; P = 0.001) and renal function (AUC creatinine: 1640(248) versus 2328(154) micromol/l.h; P = 0.001; AUC creatinine clearance: 6.94(5.03) versus 0.96(0.32) ml per min per 100 g.h; P = 0.004). Oxidative damage was also reduced by hydrogen sulphide (urinary 8-isoprostane at 1 h of reperfusion: 478.9(237.1) versus 1605.6(632.7) pg/ml per mmol/l creatinine; P = 0.032). CONCLUSION : Hydrogen sulphide ameliorated the renal dysfunction associated with ischaemic damage, and has potential as a therapy against IR injury in NHB donor kidney transplantation.
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Affiliation(s)
- S A Hosgood
- Department of Infection, Immunity and Inflammation, Transplant Group, University of Leicester, Leicester General Hospital, Leicester LE5 4PW, UK
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207
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Zhang JH, Dong Z, Chu L. Hydrogen sulfide induces apoptosis in human periodontium cells. J Periodontal Res 2010; 45:71-8. [DOI: 10.1111/j.1600-0765.2009.01202.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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208
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Martin GR, McKnight GW, Dicay MS, Coffin CS, Ferraz JGP, Wallace JL. Hydrogen sulphide synthesis in the rat and mouse gastrointestinal tract. Dig Liver Dis 2010; 42:103-9. [PMID: 19570733 DOI: 10.1016/j.dld.2009.05.016] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Revised: 04/20/2009] [Accepted: 05/15/2009] [Indexed: 12/11/2022]
Abstract
AIMS Hydrogen sulphide (H2S) exerts several anti-inflammatory effects, accelerates the healing of experimental gastric ulcers, and can stimulate intestinal secretion. Little is known about H2S synthesis in the gastrointestinal tract. The aim of this study was to characterize H2S synthesis throughout the gastrointestinal tract. METHODS H2S synthesis in various gastrointestinal tissues of rats and mice was determined. The effects and selectivity of inhibitors of two key enzymes for H2S synthesis, cystathionine-gamma-lyase and cystathionine-beta-synthase, were examined. Cystathionine-gamma-lyase and cystathionine-beta-synthase expression was evaluated by Western blotting and immunohistochemistry. Cystathionine-gamma-lyase and cystathionine-beta-synthase expression in biopsies of human colon was also examined. RESULTS H2S synthesis was variable throughout the gastrointestinal tract in parallel with variations in cystathionine-gamma-lyase and cystathionine-beta-synthase expression. The efficacy of cystathionine-beta-synthase and cystathionine-gamma-lyase inhibitors to reduce H2S synthesis in these tissues was also variable. Cystathionine-beta-synthase is the predominant source of H2S synthesis in the colon of rodents. Cystathionine-gamma-lyase and cystathionine-beta-synthase were also expressed in healthy human colon biopsies. CONCLUSIONS The capacity for H2S synthesis varies throughout the rodent gastrointestinal tract, as does the distribution and contribution of the two key enzymes. Investigation of additional enzymatic sources of H2S and the development of more selective inhibitors are suggested.
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Affiliation(s)
- Gary R Martin
- Inflammation Research Network, Department of Medicine, University of Calgary, Calgary, Alberta, Canada T2N 4N1
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209
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Wallace JL, Caliendo G, Santagada V, Cirino G. Markedly reduced toxicity of a hydrogen sulphide-releasing derivative of naproxen (ATB-346). Br J Pharmacol 2010; 159:1236-46. [PMID: 20128814 DOI: 10.1111/j.1476-5381.2009.00611.x] [Citation(s) in RCA: 172] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Hydrogen sulphide is an important mediator of gastric mucosal defence. The use of non-steroidal anti-inflammatory drugs continues to be limited by their toxicity, particularly in the upper gastrointestinal tract. We evaluated the gastrointestinal safety and anti-inflammatory efficacy of a novel hydrogen sulphide-releasing derivative of naproxen, ATB-346 [2-(6-methoxy-napthalen-2-yl)-propionic acid 4-thiocarbamoyl-phenyl ester]. EXPERIMENTAL APPROACH The ability of ATB-346 versus naproxen to cause gastric damage was evaluated in healthy rats and in rats with compromised gastric mucosal defence. Effects on the small intestine and on the healing of ulcers were also assessed. The ability of ATB-346 to inhibit cyclooxygenase-1 and 2 and to reduce inflammation in vivo was also evaluated. KEY RESULTS ATB-346 suppressed gastric prostaglandin E(2) synthesis as effectively as naproxen, but produced negligible damage in the stomach and intestine. In situations in which the gastric mucosa was rendered significantly more susceptible to naproxen-induced damage (e.g. ablation of sensory afferent nerves, inhibition of endogenous nitric oxide or hydrogen sulphide synthesis, co-administration with aspirin, antagonism of K(IR)6.x channels), ATB-346 did not cause significant damage. Unlike naproxen and celecoxib, ATB-346 accelerated healing of pre-existing gastric ulcers. In a mouse airpouch model, ATB-346 suppressed cyclooxygenase-2 activity and inhibited leukocyte infiltration more effectively than naproxen. ATB-346 was as effective as naproxen in adjuvant-induced arthritis in rats, with a more rapid onset of activity. Unlike naproxen, ATB-346 did not elevate blood pressure in hypertensive rats. CONCLUSIONS AND IMPLICATIONS ATB-346 exhibits anti-inflammatory properties similar to naproxen, but with substantially reduced gastrointestinal toxicity.
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Affiliation(s)
- John L Wallace
- Farncombe Family Digestive Health Research Institute, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada.
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210
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Abstract
Nitric oxide (NO) and carbon monoxide (CO) are well established as messenger molecules throughout the body, gasotransmitters, based on striking alterations in mice lacking the appropriate biosynthetic enzymes. Hydrogen sulfide (H(2)S) is even more chemically reactive, but until recently there was little definitive evidence for its physiologic formation. Cystathionine beta-synthase (EC 4.2.1.22), and cystathionine gamma-lyase (CSE; EC 4.4.1.1), also known as cystathionine, can generate H(2)S from cyst(e)ine. Very recent studies with mice lacking these enzymes have established that CSE is responsible for H(2)S formation in the periphery, while in the brain cystathionine beta-synthase is the biosynthetic enzyme. Endothelial-derived relaxing factor activity is reduced 80% in the mesenteric artery of mice with deletion of CSE, establishing H(2)S as a major physiologic endothelial-derived relaxing factor. H(2)S appears to signal predominantly by S-sulfhydrating cysteines in its target proteins, analogous to S-nitrosylation by NO. Whereas S-nitrosylation typically inhibits enzymes, S-sulfhydration activates them. S-nitrosylation basally affects 1-2% of its target proteins, while 10-25% of H(2)S target proteins are S-sulfhydrated. In summary, H(2)S appears to be a physiologic gasotransmitter of comparable importance to NO and carbon monoxide.
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Affiliation(s)
- Moataz M Gadalla
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2105, USA
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211
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Zanatta SD, Jarrott B, Williams SJ. Synthesis and Preliminary Pharmacological Evaluation of Aryl Dithiolethiones with Cyclooxygenase-2-Selective Inhibitory Activity and Hydrogen Sulfide-Releasing Properties. Aust J Chem 2010. [DOI: 10.1071/ch09517] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A series of 5-aryl-1,2-dithiolethiones and 5-aryl-1,2-dithiole-3-ones were investigated as hydrogen sulfide-releasing anti-inflammatory drugs. Generally, phenolic acetophenones were best protected by methoxymethyl groups and the dithiolethione group installed by treatment with carbon disulfide, hexamethyldisilathiane, and hexachloroethane. However, ether-protected acetophenones could be elaborated to β-keto esters and converted to dithiolethiones by treatment with phosphorus pentasulfide and elemental sulfur. Dethionation of dithiolethiones to 1,2-dithiole-3-ones was accomplished by mercury(ii)-promoted hydrolysis. A preliminary investigation of the dithiolethiones and dithiole-3-ones as inhibitors of cyclooxygenases COX-1 and COX-2 is discussed. Dithiolethiones bearing a 5-(2,6-di-tert-butyl-4-hydroxyphenyl) or 5-(2,6-di-tert-butyl-4-methoxyphenyl) substituent were the most effective inhibitors of COX-2 and displayed excellent selectivity against COX-1, comparable with rofecoxib, a representative coxib. It is shown that uncatalyzed hydrolysis of the thiocarbonyl group to release hydrogen sulfide leads to the corresponding carbonyl compound, and these carbonyl compounds are moderate COX-2 selective inhibitors.
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212
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Kashfi K. Anti-inflammatory agents as cancer therapeutics. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2009; 57:31-89. [PMID: 20230759 DOI: 10.1016/s1054-3589(08)57002-5] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cancer prevention sometimes referred to as tertiary prevention or chemoprevention makes use of specific xenobiotics or drugs to prevent, delay, or retard the development of cancer. Over the last two decades or so cancer prevention has made significant strides. For example, prevention of lung cancer through smoking cessation; cervical cancer prevention through regular Pap smear tests; colon cancer prevention through screening colonoscopy; and prostate cancer reductions by prostate-specific antigen measurements in conjunction with regular prostate examinations. The seminal epidemiological observation that nonsteroidal anti-inflammatory drugs (NSAIDs) prevent colon and other cancers has provided the impetus to develop novel chemoprevention approaches against cancer. To that end, a number of "designer drugs" have been synthesized that are in different stages of development, evaluation, and deployment. Some include the cyclooxygenase-2-specific inhibitors (coxibs), nitric oxide-releasing NSAIDs (NO-NSAIDs and NONO-NSAIDs), hydrogen sulfide-releasing NSAIDs, modulators of the lipoxygenase pathway, prostanoid receptor blockers, and chemokine receptor antagonists. In addition to these novel agents, there are also a host of naturally occurring compounds/micronutrients that have chemopreventive properties. This chapter reviews these classes of compounds, their utility and mechanism(s) of action against the background of mediators that link inflammation and cancer.
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Affiliation(s)
- Khosrow Kashfi
- Department of Physiology and Pharmacology, Sophie Davis School of Biomedical Education, The City College of The City University of New York, New York 10031, USA
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213
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Hughes MN, Centelles MN, Moore KP. Making and working with hydrogen sulfide: The chemistry and generation of hydrogen sulfide in vitro and its measurement in vivo: a review. Free Radic Biol Med 2009; 47:1346-53. [PMID: 19770036 DOI: 10.1016/j.freeradbiomed.2009.09.018] [Citation(s) in RCA: 334] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Revised: 09/17/2009] [Accepted: 09/17/2009] [Indexed: 12/20/2022]
Abstract
Hydrogen sulfide is rapidly emerging as an important vasoactive mediator formed in health and disease. Its biological action is centered on its reactivity with heme-proteins and its ability to activate K(ATP) channels. Hydrogen sulfide is a signalling molecule of the inflammatory and nervous systems, and in particular the cardiovascular system where it regulates vascular tone, cardiac work, and exerts cardioprotection. This has led to an explosion of papers in which the role of hydrogen sulfide generated in vitro has been used to stimulate biological responses, and where a variety of methods have been used to measure the concentration of this compound in biological fluids. Understanding the chemistry and the inherent problems in the analytical techniques used to measure hydrogen sulfide concentrations is critical to our expanding knowledge on the biology of hydrogen sulfide. In this brief review we will cover the chemistry of hydrogen sulfide, including sources of hydrogen sulfide, its speciation at physiological pH, the susceptibility of sulfide to aerobic oxidation, and the methods used to measure hydrogen sulfide concentrations in solution, including biological fluids. We also give a brief overview of knockout animals and inhibition of the enzymes involved in the formation of hydrogen sulfide in vivo.
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Affiliation(s)
- Martin N Hughes
- Centre for Hepatology, Department of Medicine, University College London Medical School, London NW3 2PF, UK.
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214
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Fang LP, Lin Q, Tang CS, Liu XM. Hydrogen sulfide attenuates epithelial-mesenchymal transition of human alveolar epithelial cells. Pharmacol Res 2009; 61:298-305. [PMID: 19913099 DOI: 10.1016/j.phrs.2009.10.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Revised: 10/25/2009] [Accepted: 10/28/2009] [Indexed: 02/06/2023]
Abstract
We previously reported that the endogenous cystathionine gamma-lyase (CSE)/hydrogen sulfide (H(2)S) pathway is implicated in the pathogenesis of bleomycin-induced pulmonary fibrosis in rats, but the exact cellular mechanisms are not well characterized. Epithelial-mesenchymal transition (EMT), induced by transforming growth factor beta1 (TGF-beta1) in alveolar epithelial cells, plays an important role in the pathogenesis of pulmonary fibrosis. We studied whether H(2)S could attenuate EMT in cultured alveolar epithelial cells and TGF-beta1 treatment suppressed CSE expression in A549 cells. Inhibition of endogenous CSE by dl-propargylglycine led to spontaneous EMT, as manifested by decreased E-cadherin level, increased vimentin expression and fibroblast-like morphologic features. Exogenous H(2)S applied to TGF-beta1-treated A549 cells decreased vimentin expression, increased E-cadherin level and retained epithelial morphologic features. In addition, preincubation with H(2)S decreased Smad2/3 phosphorylation in A549 cells stimulated by TGF-beta1, and H(2)S-inhibited alveolar EMT was mimicked by treatment with SB505124, a Smad2/3 inhibitor, but not pinacidil, an ATP-sensitive K(+) channel (K(ATP)) opener. H(2)S serves a critical role in preserving an epithelial phenotype and in attenuating EMT in alveolar epithelial cells, mediated, at least in part, by decreased Smad2/3 phosphorylation and not dependent on K(ATP) channel opening.
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Affiliation(s)
- Li-Ping Fang
- Department of Geriatrics, Peking University First Hospital, Xishiku Street No. 8, West District, Beijing, People's Republic of China
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215
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Bauer CC, Boyle JP, Porter KE, Peers C. Modulation of Ca(2+) signalling in human vascular endothelial cells by hydrogen sulfide. Atherosclerosis 2009; 209:374-80. [PMID: 19875115 DOI: 10.1016/j.atherosclerosis.2009.10.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Revised: 09/08/2009] [Accepted: 10/02/2009] [Indexed: 11/16/2022]
Abstract
Hydrogen sulfide (H(2)S) is now recognised as an important endogenous antihypertensive molecule and is synthesised in the vasculature primarily by endothelial cystathionine gamma lyase. Activity of this enzyme, and the production of other vasoactive substances by the endothelium, are subject to modulation by changes of [Ca(2+)](i). Here, we have used microfluorimetry to investigate whether H(2)S can regulate human endothelial [Ca(2+)](i). H(2)S (applied via the donor NaHS, 5-500 microM) caused concentration-dependent rises of [Ca(2+)](i) which were attributable to release from an ATP- and 4-CEP sensitive intracellular pool. Rises of [Ca(2+)](i) evoked by H(2)S were essentially abolished by prior pool depletion. In the absence of external Ca(2+), H(2)S slowed the decay phase of responses to cyclopiazonic acid, but this could not be attributed to the inhibition of Ca(2+) extrusion since the effects of H(2)S were at least additive with the Na(+)/Ca(2+) exchange inhibitors bepridil and SEA 0400 and the Ca(2+) ATPase inhibitor, carboxyeosin. In some but not all the cells, re-exposure to extracellular Ca(2+) following the addition and removal of H(2)S activated capacitative Ca(2+) entry (CCE), and H(2)S increased ATP-evoked (but not thapsigargin-evoked) CCE. Effects of H(2)S were not mediated by energy depletion or production of cyclic ADP ribose. Our data indicate that H(2)S can modulate endothelial [Ca(2+)](i) via multiple mechanisms, and such effects are likely to contribute to this gasotransmitter's beneficial actions.
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Affiliation(s)
- Claudia C Bauer
- Division of Cardiovascular and Neuronal Remodelling, Leeds Institute for Genetics Health and Therapeutics, University of Leeds, Clarendon Way, Leeds LS2 9JT, UK
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Hydrogen sulfide suppresses migration, proliferation and myofibroblast transdifferentiation of human lung fibroblasts. Pulm Pharmacol Ther 2009; 22:554-61. [PMID: 19651225 DOI: 10.1016/j.pupt.2009.07.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2008] [Revised: 04/02/2009] [Accepted: 07/21/2009] [Indexed: 12/15/2022]
Abstract
We previously reported that hydrogen sulfide (H(2)S) was implicated in the pathogenesis of bleomycin-induced pulmonary fibrosis in rat, but the cellular mechanisms underlying the role it played were not well characterized. The present study was undertaken to investigate the role of the exogenous H(2)S in human lung fibroblast (MRC5) migration, proliferation and myofibroblast transdifferentiation induced by fetal bovine serum (FBS) and growth factors in vitro, to elucidate the mechanisms by which H(2)S inhibits pathogenesis of pulmonary fibrosis. We found that H(2)S incubation significantly decreased the MRC5 cell migration distance stimulated by FBS and basic fibroblast growth factor (bFGF), inhibited MRC5 cell proliferation induced by FBS and platelet-derived growth factor-BB (PDGF-BB), and also inhibited transforming growth factor-beta1 (TGF-beta1) induced MRC5 cell transdifferentiation into myofibroblasts. Moreover, preincubation with H(2)S decreased extracellular signal-regulated kinase (ERK1/2) phosphorylation in MRC5 cells induced by FBS, PDGF-BB, TGF-beta1, and bFGF. However, the inhibition effects of H(2)S on MRC5 cell migration, proliferation and myofibroblast transdifferentiation were not attenuated by glibenclamide, an ATP-sensitive K(+) channel (K(ATP)) blocker. Thus, H(2)S directly suppressed fibroblast migration, proliferation and phenotype transform stimulated by FBS and growth factors in vitro, which suggests that it could be an important mechanism of H(2)S-suppressed pulmonary fibrosis. These effects of H(2)S on pulmonary fibroblasts were, at least in part, mediated by decreased ERK phosphorylation and were not dependent on K(ATP) channel opening.
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217
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Ganta VC, Alexander JS. Focus on carbon monoxide: a modulator of neutrophil oxidants and elastase spatial localization? Am J Physiol Heart Circ Physiol 2009; 297:H902-4. [PMID: 19592608 DOI: 10.1152/ajpheart.00587.2009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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218
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Li L, Salto-Tellez M, Tan CH, Whiteman M, Moore PK. GYY4137, a novel hydrogen sulfide-releasing molecule, protects against endotoxic shock in the rat. Free Radic Biol Med 2009; 47:103-13. [PMID: 19375498 DOI: 10.1016/j.freeradbiomed.2009.04.014] [Citation(s) in RCA: 198] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Revised: 04/07/2009] [Accepted: 04/10/2009] [Indexed: 02/01/2023]
Abstract
GYY4137 (morpholin-4-ium-4-methoxyphenyl(morpholino) phosphinodithioate) is a slow-releasing hydrogen sulfide (H(2)S) donor. Administration of GYY4137 (50 mg/kg, iv) to anesthetized rats 10 min after lipopolysaccharide (LPS; 4 mg/kg, iv) decreased the slowly developing hypotension. GYY4137 inhibited LPS-induced TNF-alpha production in rat blood and reduced the LPS-evoked rise in NF-kappaB activation, inducible nitric oxide synthase/cyclooxygenase-2 expression, and generation of PGE(2) and nitrate/nitrite in RAW 264.7 macrophages. GYY4137 (50 mg/kg, ip) administered to conscious rats 1 or 2 h after (but not 1 h before) LPS decreased the subsequent (4 h) rise in plasma proinflammatory cytokines (TNF-alpha, IL-1beta, IL-6), nitrite/nitrate, C-reactive protein, and L-selectin. GYY4137 administration also decreased the LPS-evoked increase in lung myeloperoxidase activity, increased plasma concentration of the anti-inflammatory cytokine IL-10, and decreased tissue damage as determined histologically and by measurement of plasma creatinine and alanine aminotransferase activity. Time-expired GYY4137 (50 mg/kg, ip) did not affect the LPS-induced rise in plasma TNF-alpha or lung myeloperoxidase activity. GYY4137 also decreased the LPS-mediated upregulation of liver transcription factors (NF-kappaB and STAT-3). These results suggest an anti-inflammatory effect of GYY4137. The possibility that GYY4137 and other slow-releasing H(2)S donors exert anti-inflammatory activity in other models of inflammation and in humans warrants further study.
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Affiliation(s)
- Ling Li
- Pharmaceutical Science Research Division, King's College, University of London, London, UK
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219
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Singh S, Padovani D, Leslie RA, Chiku T, Banerjee R. Relative contributions of cystathionine beta-synthase and gamma-cystathionase to H2S biogenesis via alternative trans-sulfuration reactions. J Biol Chem 2009; 284:22457-22466. [PMID: 19531479 DOI: 10.1074/jbc.m109.010868] [Citation(s) in RCA: 472] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In mammals, the two enzymes in the trans-sulfuration pathway, cystathionine beta-synthase (CBS) and cystathionine gamma-lyase (CSE), are believed to be chiefly responsible for hydrogen sulfide (H2S) biogenesis. In this study, we report a detailed kinetic analysis of the human and yeast CBS-catalyzed reactions that result in H2S generation. CBS from both organisms shows a marked preference for H2S generation by beta-replacement of cysteine by homocysteine. The alternative H2S-generating reactions, i.e. beta-elimination of cysteine to generate serine or condensation of 2 mol of cysteine to generate lanthionine, are quantitatively less significant. The kinetic data were employed to simulate the turnover numbers of the various CBS-catalyzed reactions at physiologically relevant substrate concentrations. At equimolar concentrations of CBS and CSE, the simulations predict that H2S production by CBS would account for approximately 25-70% of the total H2S generated via the trans-sulfuration pathway depending on the extent of allosteric activation of CBS by S-adenosylmethionine. The relative contribution of CBS to H2S genesis is expected to decrease under hyperhomocysteinemic conditions. CBS is predicted to be virtually the sole source of lanthionine, and CSE, but not CBS, efficiently cleaves lanthionine. The insensitivity of the CBS-catalyzed H2S-generating reactions to the grade of hyperhomocysteinemia is in stark contrast to the responsiveness of CSE and suggests a previously unrecognized role for CSE in intracellular homocysteine management. Finally, our studies reveal that the profligacy of the trans-sulfuration pathway results not only in a multiplicity of H2S-yielding reactions but also yields novel thioether metabolites, thus increasing the complexity of the sulfur metabolome.
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Affiliation(s)
- Sangita Singh
- Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109
| | - Dominique Padovani
- Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109
| | - Rachel A Leslie
- Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109
| | - Taurai Chiku
- Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109
| | - Ruma Banerjee
- Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109
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220
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Xu Z, Prathapasinghe G, Wu N, Hwang SY, Siow YL, O K. Ischemia-reperfusion reduces cystathionine-beta-synthase-mediated hydrogen sulfide generation in the kidney. Am J Physiol Renal Physiol 2009; 297:F27-35. [PMID: 19439522 DOI: 10.1152/ajprenal.00096.2009] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Cystathionine-beta-synthase (CBS) catalyzes the rate-limiting step in the transsulfuration pathway for the metabolism of homocysteine (Hcy) in the kidney. Our recent study demonstrates that ischemia-reperfusion reduces the activity of CBS leading to Hcy accumulation in the kidney, which in turn contributes to renal injury. CBS is also capable of catalyzing the reaction of cysteine with Hcy to produce hydrogen sulfide (H(2)S), a gaseous molecule that plays an important role in many physiological and pathological processes. The aim of the present study was to examine the effect of ischemia-reperfusion on CBS-mediated H(2)S production in the kidney and to determine whether changes in the endogenous H(2)S generation had any impact on renal ischemia-reperfusion injury. The left kidney of Sprague-Dawley rat was subjected to 45-min ischemia followed by 6-h reperfusion. The ischemia-reperfusion caused lipid peroxidation and cell death in the kidney. The CBS-mediated H(2)S production was decreased, leading to a significant reduction in the renal H(2)S level. The activity of cystathionine-gamma-lyase, another enzyme responsible for endogenous H(2)S generation, was not significantly altered in the kidney upon ischemia-reperfusion. Partial restoration of CBS activity by intraperitoneal injection of the nitric oxide scavenger, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide not only increased renal H(2)S levels but also alleviated ischemia-reperfusion-induced lipid peroxidation and reduced cell damage in the kidney tissue. Furthermore, administration of an exogenous H(2)S donor, NaHS (100 microg/kg), improved renal function. Taken together, these results suggest that maintenance of tissue H(2)S level may offer a renal protective effect against ischemia-reperfusion injury.
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Affiliation(s)
- Zhibin Xu
- Department of Animal Science, University of Manitoba, Winnipeg, Manitoba, Canada
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221
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Li YF, Xiao CS, Hui RT. Calcium sulfide (CaS), a donor of hydrogen sulfide (H(2)S): a new antihypertensive drug? Med Hypotheses 2009; 73:445-7. [PMID: 19403240 DOI: 10.1016/j.mehy.2009.03.030] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Revised: 03/19/2009] [Accepted: 03/22/2009] [Indexed: 10/20/2022]
Abstract
Hypertension is the leading cause of cardiovascular diseases, and an estimated 972 million people in the world are suffering from this problem. Indubitably, hypertension is an important worldwide public-health challenge. In recent years many efforts have been made to devise novel therapies involving new targets implicated in cardiovascular diseases. Hydrogen sulfide (H(2)S) is a member of a growing family of "gasotransmitters". It is clear that H(2)S plays a pivotal role in the basal regulation of vessels tone. Also studies demonstrate that intravenous sodium hydrosulfide (NaHS), a donor of H(2)S, dose-dependently decreases systolic blood pressure. However, because of its active chemical property, NaHS can be easily oxidized, even spontaneously ignited in the open air. Moreover, its solution is not stable. So the pharmacal use of NaHS is limited by its properties. Calcium sulfide (CaS), one of the effective components in a traditional herb, is another donor of H(2)S. It has more stable chemical properties than NaHS. We hypotheses that CaS might be given by mouth as a new antihypertensive drug through certain dosage form designing. To test this hypothesis, we should establish animal models for studies including drug efficacy, drug safety, drug toxicology, drug metabolism and drug kinetics.
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Affiliation(s)
- Ya-Feng Li
- Department of Cardiology, The Second Hospital of Shanxi Medical University, 382 Wuyi Road, Taiyuan 030001, PR China
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222
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Olson KR. Is hydrogen sulfide a circulating "gasotransmitter" in vertebrate blood? BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:856-63. [PMID: 19361483 DOI: 10.1016/j.bbabio.2009.03.019] [Citation(s) in RCA: 188] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Revised: 03/26/2009] [Accepted: 03/31/2009] [Indexed: 10/20/2022]
Abstract
Hydrogen sulfide (H(2)S) is gaining acceptance as a signaling molecule and has been shown to elicit a variety of biological effects at concentrations between 10 and 1000 micromol/l. Dissolved H(2)S is a weak acid in equilibrium with HS(-) and S(2-) and under physiological conditions these species, collectively referred to as sulfide, exist in the approximate ratio of 20% H(2)S, 80% HS(-) and 0% S(2-). Numerous analyses over the past 8 years have reported plasma or blood sulfide concentrations also in this range, typically between 30 and 300 micromol/l, thus supporting the biological studies. However, there is some question whether or not these concentrations are physiological. First, many of these values have been obtained from indirect methods using relatively harsh chemical conditions. Second, most studies conducted prior to 2000 failed to find blood sulfide in micromolar concentrations while others showed that radiolabeled (35)S-sulfide is rapidly removed from blood and that mammals have a relatively high capacity to metabolize exogenously administered sulfide. Very recent studies using H(2)S gas-sensing electrodes to directly measure sulfide in plasma or blood, or HPLC analysis of head-space gas, have also indicated that sulfide does not circulate at micromolar levels and is rapidly consumed by blood or tissues. Third, micromolar concentrations of sulfide in blood or exhaled air should be, but are not, malodorous. Fourth, estimates of dietary sulfur necessary to sustain micromolar levels of plasma sulfide greatly exceed the daily intake. Collectively, these studies imply that many of the biological effects of sulfide are only achieved at supra-physiological concentrations and they question whether circulating sulfide is a physiologically relevant signaling molecule. This review examines the blood/plasma sulfide measurements that have been reported over the past 30 years from the perspective of the analytical methods used and the potential sources of error.
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Affiliation(s)
- Kenneth R Olson
- Indiana University School of Medicine-South Bend, 1234 Notre Dame Avenue, South Bend, IN 46617, USA.
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223
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Jarrott B, Zanatta S, Williams SJ. Development of a substituted phenyldithiolethione as a novel cyclooxygenase inhibitor with minimal gastro‐irritancy. FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.lb369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Shannon Zanatta
- Howard Florey Institute
- School of ChemistryUniversity of MelbourneParkvilleAustralia
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224
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Janga SC, Tzakos A. Structure and organization of drug-target networks: insights from genomic approaches for drug discovery. MOLECULAR BIOSYSTEMS 2009; 5:1536-48. [DOI: 10.1039/b908147j] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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225
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Lu M, Hu LF, Hu G, Bian JS. Hydrogen sulfide protects astrocytes against H(2)O(2)-induced neural injury via enhancing glutamate uptake. Free Radic Biol Med 2008; 45:1705-13. [PMID: 18848879 DOI: 10.1016/j.freeradbiomed.2008.09.014] [Citation(s) in RCA: 148] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Revised: 08/22/2008] [Accepted: 09/06/2008] [Indexed: 12/26/2022]
Abstract
Excess extracellular glutamate, the main excitatory neurotransmitter, may result in excitotoxicity and neural injury. The present study was designed to study the effect of hydrogen sulfide (H(2)S), a novel neuromodulator, on hydrogen peroxide (H(2)O(2)) -induced glutamate uptake impairment and cellular injuries in primary cultured rat cortical astrocytes. We found that NaHS (an H(2)S donor, 0.1-1000 microM) reversed H(2)O(2)-induced cellular injury in a concentration-dependent manner. This effect was attenuated by L-trans-pyrrolidine-2,4-dicarboxylic (PDC), a specific glutamate uptake inhibitor. Moreover, NaHS significantly increased [(3)H]glutamate transport in astrocytes treated with H(2)O(2), suggesting that H(2)S may protect astrocytes via enhancing glutamate uptake function. NaHS also reversed H(2)O(2)-impaired glutathione (GSH) production. Blockade of glutamate uptake with PDC attenuated this effect, indicating that the effect of H(2)S on GSH production is secondary to the stimulation of glutamate uptake. In addition, it was also found that H(2)S may promote glutamate uptake activity via decreasing ROS generation, enhancing ATP production and suppressing ERK1/2 activation. In conclusion, our findings provide direct evidence that H(2)S has potential therapeutic value for oxidative stress-induced brain damage via a mechanism involving enhancing glutamate uptake function.
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Affiliation(s)
- Ming Lu
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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226
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Synthesis and evaluation of dithiolethiones as novel cyclooxygenase inhibitors. Bioorg Med Chem Lett 2008; 19:459-61. [PMID: 19056264 DOI: 10.1016/j.bmcl.2008.11.045] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Revised: 11/12/2008] [Accepted: 11/13/2008] [Indexed: 11/24/2022]
Abstract
3H-1,2-Dithiole-3-thiones substituted with a 3,5-di-tert-butyl-4-hydroxyphenyl (DTBHP) or a 3,5-di-tert-butyl-4-methoxyphenyl group at the C5 position were prepared and their ability to inhibit the cyclooxygenase isoenzymes, COX-1 and COX-2 was evaluated. Both compounds were potent inhibitors of COX-2 (relative to rofecoxib), and while the phenol was a weak inhibitor of COX-1, the methyl ether gave no measurable inhibition. Docking studies of the two compounds into the COX-1 and -2 active sites showed that the methyl ether could only fit in the COX-2 active site whereas the phenol could be docked into both COX-1 and -2. This study reports a new mode for inhibitor binding to COX-1 and -2 and a novel structural scaffold for the development of COX-2 selective inhibitors.
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227
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Olson KR. Hydrogen sulfide and oxygen sensing: implications in cardiorespiratory control. ACTA ACUST UNITED AC 2008; 211:2727-34. [PMID: 18723529 DOI: 10.1242/jeb.010066] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Although all cells are variously affected by oxygen, a few have the responsibility of monitoring oxygen tensions and initiating key homeostatic responses when P(O2) falls to critical levels. These ;oxygen-sensing' cells include the chemoreceptors in the gills (neuroepithelial cells), airways (neuroepithelial bodies) and vasculature (carotid bodies) that initiate cardiorespiratory reflexes, oxygen sensitive chromaffin cells associated with systemic veins or adrenal glands that regulate the rate of catecholamine secretion, and vascular smooth muscle cells capable of increasing blood flow to systemic tissues, or decreasing it through the lungs. In spite of intense research, and enormous clinical applicability, there is little, if any, consensus regarding the mechanism of how these cells sense oxygen and transduce this into the appropriate physiological response. We have recently proposed that the metabolism of hydrogen sulfide (H2S) may serve as an 'oxygen sensor' in vertebrate vascular smooth muscle and preliminary evidence suggests it has similar activity in gill chemoreceptors. In this proposed mechanism, the cellular concentration of H2S is determined by the simple balance between constitutive H2S production in the cytoplasm and H2S oxidation in the mitochondria; when tissue oxygen levels fall the rate of H2S oxidation decreases and the concentration of biologically active H2S in the tissue increases. This commentary briefly describes the oxygen-sensitive tissues in fish and mammals, delineates the current hypotheses of oxygen sensing by these tissues, and then critically evaluates the evidence for H2S metabolism in oxygen sensing.
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Affiliation(s)
- Kenneth R Olson
- Indiana University School of Medicine, South Bend Center, South Bend, Indiana 46617, USA.
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228
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Wallace JL. Prostaglandins, NSAIDs, and gastric mucosal protection: why doesn't the stomach digest itself? Physiol Rev 2008; 88:1547-65. [PMID: 18923189 DOI: 10.1152/physrev.00004.2008] [Citation(s) in RCA: 405] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Except in rare cases, the stomach can withstand exposure to highly concentrated hydrochloric acid, refluxed bile salts, alcohol, and foodstuffs with a wide range of temperatures and osmolarity. This is attributed to a number of physiological responses by the mucosal lining to potentially harmful luminal agents, and to an ability to rapidly repair damage when it does occur. Since the discovery in 1971 that prostaglandin synthesis could be blocked by aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs), there has been great interest in the contribution of prostaglandins to gastric mucosal defense. Prostaglandins modulate virtually every aspect of mucosal defense, and the importance of this contribution is evident by the increased susceptibility of the stomach to injury following ingestion of an NSAID. With chronic ingestion of these drugs, the development of ulcers in the stomach is a significant clinical concern. Research over the past two decades has helped to identify some of the key events triggered by NSAIDs that contribute to ulcer formation and/or impair ulcer healing. Recent research has also highlighted the fact that the protective functions of prostaglandins in the stomach can be carried out by other mediators, in particular the gaseous mediators nitric oxide and hydrogen sulfide. Better understanding of the mechanisms through which the stomach is able to resist injury in the presence of luminal irritants is helping to drive the development of safer anti-inflammatory drugs, and therapies to accelerate and improve the quality of ulcer healing.
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Affiliation(s)
- John L Wallace
- Inflammation Research Network, University of Calgary, Calgary, Alberta, Canada.
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229
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Chávez-Piña AE, Vong L, McKnight W, Dicay M, Zanardo RCO, Ortiz MI, Castañeda-Hernández G, Wallace JL. Lack of effects of acemetacin on signalling pathways for leukocyte adherence may explain its gastrointestinal safety. Br J Pharmacol 2008; 155:857-64. [PMID: 18695646 DOI: 10.1038/bjp.2008.316] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND AND PURPOSE Acemetacin is a non-steroidal anti-inflammatory drug which is rapidly bioconverted to indomethacin, but produces significantly less gastric damage than indomethacin. This study was performed to investigate several possible mechanisms that could account for the gastrointestinal tolerability of acemetacin. EXPERIMENTAL APPROACH The gastric and intestinal damaging effects of acemetacin and indomethacin were examined in the rat. Effects of the drugs on blood levels of leukotriene B(4) and thromboxane B(2), on leukocyte-endothelial adherence in post-capillary mesenteric venules, and on gastric expression of tumour necrosis factor-alpha (TNF-alpha) were determined. The two drugs were also compared for gastric toxicity in rats pretreated with inhibitors of COX-2 and NOS. KEY RESULTS Acemetacin induced significantly less gastric and intestinal damage than indomethacin, despite markedly suppressing COX activity. Indomethacin, but not acemetacin, significantly increased leukocyte adherence within mesenteric venules, and gastric expression of TNF-alpha. Pretreatment with L-nitro-arginine methyl ester or lumiracoxib increased the severity of indomethacin-induced gastric damage, but this was not the case with acemetacin. CONCLUSIONS AND IMPLICATIONS The increased gastric and intestinal tolerability of acemetacin may be related to the lack of induction of leukocyte-endothelial adherence. This may be attributable to the reduced ability of acemetacin to elevate leukotriene-B(4) synthesis and TNF-alpha expression, compared to indomethacin, despite the fact that acemetacin is rapidly bioconverted to indomethacin after its absorption.
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Affiliation(s)
- A E Chávez-Piña
- Sección Externa de Farmacología, CINVESTAV/IPN, Mexico City, DF, Mexico
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230
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Whitfield NL, Kreimier EL, Verdial FC, Skovgaard N, Olson KR. Reappraisal of H2S/sulfide concentration in vertebrate blood and its potential significance in ischemic preconditioning and vascular signaling. Am J Physiol Regul Integr Comp Physiol 2008; 294:R1930-7. [PMID: 18417642 DOI: 10.1152/ajpregu.00025.2008] [Citation(s) in RCA: 260] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hydrogen sulfide (H(2)S) is rapidly emerging as a biologically significant signaling molecule. Studies published before 2000 report low or undetectable H(2)S (usually as total sulfide) levels in blood or plasma, whereas recent work has reported sulfide concentrations between 10 and 300 microM, suggesting it acts as a circulating signal. In the first series of experiments, we used a recently developed polarographic sensor to measure the baseline level of endogenous H(2)S gas and turnover of exogenous H(2)S gas in real time in blood from numerous animals, including lamprey, trout, mouse, rat, pig, and cow. We found that, contrary to recent reports, H(2)S gas was essentially undetectable (<100 nM total sulfide) in all animals. Furthermore, exogenous sulfide was rapidly removed from blood, plasma, or 5% bovine serum albumin in vitro and from intact trout in vivo. To determine if blood H(2)S could transiently increase, we measured oxygen-dependent H(2)S production by trout hearts in vitro and in vivo. H(2)S has been shown to mediate ischemic preconditioning (IPC) in mammals. IPC is present in trout and, unlike mammals, the trout myocardium obtains its oxygen from relatively hypoxic systemic venous blood. In vitro, myocardial H(2)S production was inversely related to Po(2), whereas we failed to detect H(2)S in ventral aortic blood from either normoxic or hypoxic fish in vivo. These results provide an autocrine or paracrine mechanism for myocardial coupling of hypoxia to H(2)S in IPC, i.e., oxygen sensing, but they fail to provide any evidence that H(2)S signaling is mediated by the circulation.
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Affiliation(s)
- Nathan L Whitfield
- Indiana University School of Medicine-South Bend, 1234 Notre Dame Avenue, South Bend, IN 46617, USA
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231
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Brittain T, Yosaatmadja Y, Henty K. The interaction of human neuroglobin with hydrogen sulphide. IUBMB Life 2008; 60:135-8. [DOI: 10.1002/iub.16] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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