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Objective: Hydrogen sulfide (H2S) is a gaseous mediator produced in the body. In experimental models, endogenously produced H2S has been shown to have pro-inflammatory effects. The aim of this study was to investigate whether H2S is present in three common rheumatic diseases, rheumatoid arthritis (RA), gout and osteoarthritis (OA) and to determine if H2S levels correlate with disease activity. Methods: Patients with RA, gout, OA, and healthy controls (n = 30 each) were recruited. Plasma and where possible, synovial fluid (SF), were obtained. Levels of H2S and interleukin-6 (IL-6) (a known inflammatory marker as a positive control) were determined and assessed for their relationship with disease activity. Results: SF-H2S levels were significantly elevated in both RA and gout when compared to respective plasma levels. Plasma levels of H2S were not different from those in healthy controls in patients with either RA or gout. In OA, plasma levels of H2S were significantly elevated compared to healthy controls. In RA, SF-H2S levels correlated with Disease Activity Score (DAS)-28 and tender joint count. Conclusion: H2S is present in the joint and acts as a pro-inflammatory mediator in rheumatic diseases. H2S may be a novel therapeutic target for these conditions. [ABSTRACT FROM AUTHOR]

Acute pancreatitis (AP) has been associated with an up-regulation of substance P (SP) and neurokinin-1 receptor (NK1R) in the pancreas. Increased SP-NK1R interaction was suggested to be pro-inflammatory during AP. Previously, we showed that caerulein treatment increased SP/NK1R expression in mouse pancreatic acinar cells, but the effect of SP treatment was not evaluated. Pancreatic acinar cells were obtained from pancreas of male swiss mice (25-30 g). We measured mRNA expression of preprotachykinin-A (PPTA) and NK1R following treatment of SP (10−6M). SP treatment increased PPTA and NK1R expression in isolated pancreatic acinar cells, which was abolished by pretreatment of a selective NK1R antagonist, CP96,345. SP also time dependently increased protein expression of NK1R. Treatment of cells with a specific NK1R agonist, GR73,632, up-regulated SP protein levels in the cells. Using previously established concentrations, pre-treatment of pancreatic acinar cells with Gö6976 (10 nM), rottlerin (5 μM), PD98059 (30 μM), SP600125 (30 μM) or Bay11-7082 (30 μM) significantly inhibited up-regulation of SP and NK1R. These observations suggested that the PKC-ERK/JNK-NF-κB pathway is necessary for the modulation of expression levels. In comparison, pre-treatment of CP96,345 reversed gene expression in SP-induced cells, but not in caerulein-treated cells. Overall, the findings in this study suggested a possible auto-regulatory mechanism of SP/NK1R expression in mouse pancreatic acinar cells, via activation of NK1R. Elevated SP levels during AP might increase the occurrence of a positive feedback loop that contributes to abnormally high expression of SP and NK1R. [ABSTRACT FROM AUTHOR]

Substance P (SP) is involved in the pathophysiology of acute pancreatitis (AP) via binding to its high-affinity receptor, neurokinin-1-receptor (NK1R). An up-regulation of SP and NK1R expression was observed in experimental AP and in caerulein-stimulated pancreatic acinar cells. However, the mechanisms that lead to this up-regulation are not fully understood. In this study, we showed the role of protein kinase C (PKC) in caerulein-induced SP and NK1R production in isolated mouse pancreatic acinar cells. Caerulein (10−7 M) stimulation rapidly activated the conventional PKC-α and novel PKC-δ as observed by the phosphorylation of these molecules. Pre-treatment of pancreatic acinar cells with Gö6976 (1-10 nM) and rottlerin (1-10 μM) inhibited PKC-α and PKC-δ phosphorylation, respectively, but not the other way round. At these concentrations used, PKC-α and PKC-δ inhibition reversed the caerulein-induced up-regulation of SP and NK1R, indicating an important role of PKCs in the modulation of SP and NK1R expression. Further experiments looking into signalling mechanisms showed that treatment of pancreatic acinar cells with both Gö6976 and rottlerin inhibited the activation of extracellular signal-regulated kinase 1/2 (ERK1/2) and c-Jun N-terminal kinase (JNK). Inhibition of PKC-α or PKC-δ also affected caerulein-induced transcription factor activation, as represented by nuclear factor-κB and AP-1 DNA-binding activity. The findings in this study suggested that PKC is upstream of the mitogen-activated protein kinases and transcription factors, which then lead to the up-regulation of SP/NK1R expression in caerulein-treated mouse pancreatic acinar cells. [ABSTRACT FROM AUTHOR]

Neuropeptide modulation of immune cell function is an important mechanism of neuroimmune intersystem crosstalk. Substance P (SP) is one such key neuropeptide involved. In this study, we investigated the yet unexplored cellular mechanisms of SP-mediated inflammatory responses in macrophages using a mouse macrophage-like cell line RAW 264.7 and isolated peritoneal macrophages. We found that the conventional PKCα and novel PKCγ and ε were selectively activated by SP via its primary neurokinin-1 receptor (NK-1R) on the cells. Activation of these PKC isoforms mediated the activation of downstream extracellular signal-regulated kinase-½ (ERK½) and the transcription factor NF-κB, which drove the transcription of inducible chemokines in macrophages. Additionally, phosphoinositide 3-kinase (PI3K)-Akt was also activated by SP/NK-1R in macrophages. Inhibition of PI3K-Akt pathway attenuated ERK½ and NF-κB activation, suggesting it also played a part in SP-induced cellular inflammatory response. Kinetic analysis indicated that PKC isoforms induced early ERK½ activation, while PI3K-Akt contributed to the pathway at later time points. It was further demonstrated that PKC and PI3K-Akt were activated independent of each other. Collectively, our results suggest that SP/NK-1R activates two convergent proinflammatory signaling pathways, PKCs and PI3K-Akt, resulting in ERK½ and NF-κB activation and chemokine production in mouse macrophages. [ABSTRACT FROM AUTHOR]

Treatment of pancreatic acinar cells by hydrogen sulphide has been shown to induce apoptosis. However, a potential role of mitogenactivated protein kinases (MAPKs) in this apoptotic pathway remains unknown. The present study examined the role of MAPKs in H2S induced apoptosis in mouse pancreatic acinar cells. Pancreatic acinar cells were treated with 10 μM NaHS (a donor of H2S) for 3 hrs. For the evaluation of the role of MAPKs, PD98059, SP600125 and SB203580 were used as MAPKs inhibitors for ERK1/2, JNK1/2 and p38 MAPK, respectively. We observed activation of ERK1/2, JNK1/2 and p38 when pancreatic acini were exposed to H2S. Moreover, H2Sinduced ERK1/2, JNK1/2 and p38 activation were blocked by pre-treatment with their corresponding inhibitor in a dose-dependent manner. H2S-induced apoptosis led to an increase in caspase 3 activity and this activity was attenuated when caspase 3 inhibitor were used. Also, the cleavage of caspase 3 correlated with that of poly-(ADP-ribose)-polymerase (PARP) cleavage. H2S treatment induced the release of cytochrome c, smac from mitochondria into the cytoplasm, translocation of Bax into mitochondria and decreased the protein level of Bcl-2. Inhibition of ERK1/2 using PD98059 caused further enhancement of apoptosis as evidenced by annexin V staining, while SP600125 and SB203580 abrogated H2S-induced apoptosis. Taken together, the data suggest that activation of ERKs promotes cell survival, whereas activation of JNKs and p38 MAP kinase leads to H2S-induced apoptosis. [ABSTRACT FROM AUTHOR]

Hydrogen sulphide (H2S), a novel gasotransmitter, has been recognized to play an important role in inflammation. Cystathionine-γ-lyase (CSE) is a major H2S synthesizing enzyme in the cardiovascular system and DL-propargylglycine (PAG) is an irreversible inhibitor of CSE. Substance P (SP), a product of preprotachykinin- A (PPT-A) gene, is a well-known pro-inflammatory mediator which acts principally through the neurokinin-1 receptor (NK-1R).We have shown an association between H2S and SP in pulmonary inflammation as well as a pro-inflammatory role of H2S and SP in acute pancreatitis. The present study was aimed to investigate the interplay between pro-inflammatory effects of H2S and SP in a murine model of caerulein-induced acute pancreatitis. Acute pancreatitis was induced in mice by 10 hourly intraperitoneal injections of caerulein (50 (g/kg). PAG (100 mg/kg, i.p.) was administered either 1 hr before (prophylactic) or 1 hr after (therapeutic) the first caerulein injection. PAG, given prophylactically as well as therapeutically, significantly reduced plasma H2S levels and pancreatic H2S synthesizing activities as well as SP concentrations in plasma, pancreas and lung compared with caerulein-induced acute pancreatitis. Furthermore, prophylactic as well as therapeutic administration of PAG significantly reduced PPT-A mRNA expression and NK-1R mRNA expression in both pancreas and lung when compared with caerulein-induced acute pancreatitis. These results suggest that the pro-inflammatory effects of H2S may be mediated by SP-NK-1R pathway in acute pancreatitis. [ABSTRACT FROM AUTHOR]

Substance P, acting via its neurokinin 1 receptor (NK1 R), plays an important role in mediating a variety of inflammatory processes. Its interaction with chemokines is known to play a crucial role in the pathogenesis of acute pancreatitis. In pancreatic acinar cells, substance P stimulates the release of NFκB-driven chemokines.However, the signal transduction pathways by which substance P-NK1 R interaction induces chemokine production are still unclear. To that end, we went on to examine the participation of mitogen-activated protein kinases (MAPKs) in substance P-induced synthesis of pro-inflammatory chemokines, monocyte chemoanractant protein-1 (MCP-I), macrophage inflammatory protein-lα (MIP-lα) and macrophage inflammatory protein-2 (MIP-2), in pancreatic acini. In this study, we observed a time-dependent activation of ERK1/2, c-Jun N-terminal kinase (JNK), NFκB and activator protein-1 (AP-1) when pancreatic acini were stimulated with substance P. Moreover, substance P-induced ERK 1/2, JNK, NFκB and AP-1 activation as well as chemokine synthesis were blocked by pre-treatment with either extracellular signal-regulated protein kinase kinase 1 (MEK1) inhibitor or JNK inhibitor. In addition, substance P-induced activation of ERK 112, JNK, NFκB and AP-1-driven chemokine production were attenuated by CP96345, a selective NK1 R antagonist, in pancreatic acinar cells. Taken together, these results suggest that substance P-NK1 R induced chemokine production depends on the activation of MAPKs-mediated NFκB and AP-1 signalling pathways in mouse pancreatic acini. [ABSTRACT FROM AUTHOR]

Hydrogen sulphide (H2S) is synthesized from L-cysteine via the action of cystathionine-γ-lyase (CSE) and cystathionine-β-synthase (CBS). We have earlier shown that H2S acts as a mediator of inflammation. However the mechanism remains unclear. In this study, we investigated the presence of H2S and the expression of H2S synthesizing enzymes, CSE and CBS, in isolated mouse pancreatic acini. Pancreatic acinar cells from mice were incubated with or without caerulein (10-7 M for 30 and 60 min). Caerulein increased the levels of H2S and CSE mRNA expression while CBS mRNA expression was decreased. In addition, cells pretreated with DL-propargylglycine (PAG, 3 mM), a CSE inhibitor, reduced the formation of H2S in caerulein treated cells, suggesting that CSE may be the main enzyme involved in H2S formation in mouse acinar cells. Furthermore, substance P (SP) concentration in the acini and expression of SP gene (preprotachykinin-A, PPT-A) and neurokinin-1 receptor (NK-1R), the primary receptor for SP, are increased in secretagogue caerulein-treated acinar cells. Inhibition of endogenous production of H2S by PAG significantly suppressed SP concentration, PPT-A expression and NK1-R expression in the acini. To determine whether H2S itself provoked inflammation in acinar cells, the cells were treated with H2S donor drug, sodium hydrosulphide (NaHS), (10, 50 and 100 μM), that resulted in a significant increase in SP concentration and expression of PPT-A and NK1-R in acinar cells. These results suggest that the pro-inflammatory effect of H2S may be mediated by SPNK-1R related pathway in mouse pancreatic acinar cells. [ABSTRACT FROM AUTHOR]

The biosynthesis of both nitric oxide (NO) and hydrogen sulfide (H2S) is increased in lipopolysaccharide (LPS)-injected mice and rats but their interaction in these models is not known. In this study we examined the effect of the NO donor, nitroflurbiprofen (and the parent molecule flurbiprofen) on NO and H2S metabolism in tissues from LPS-pretreated rats.Administration of LPS (10 mg kg−1, i.p.; 6 h) resulted in an increase (P<0.05) in plasma TNF-α, IL-1β and nitrate/nitrite (NOx) concentrations, liver H2S synthesis (from added cysteine), CSE mRNA, inducible nitric oxide synthase (iNOS), myeloperoxidase (MPO) activity (marker for neutrophil infiltration) and nuclear factor-kappa B (NF-κB) activation.Nitroflurbiprofen (3–30 mg kg−1, i.p.) administration resulted in a dose-dependent inhibition of the LPS-mediated increase in plasma TNF-α, IL-1β and NOx concentration, liver H2S synthesis (55.00±0.95 nmole mg protein−1, c.f. 62.38±0.47 nmole mg protein−1, n=5, P<0.05), CSE mRNA, iNOS, MPO activity and NF-κB activation.Flurbiprofen (21 mg kg−1, i.p.) was without effect.These results show for the first time that nitroflurbiprofen downregulates the biosynthesis of proinflammatory H2S and suggest that such an effect may contribute to the augmented anti-inflammatory activity of this compound.These data also highlight the existence of ‘crosstalk’ between NO and H2S in this model of endotoxic shock.British Journal of Pharmacology (2006) 147, 966–974. doi:10.1038/sj.bjp.0706696; published online 20 February 2006 [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H2S) is a naturally occurring gaseous transmitter, which may play important roles in normal physiology and disease. Here, we investigated the role of H2S in the organ injury caused by severe endotoxemia in the rat.Male Wistar rats were subjected to acute endotoxemia (Escherichia coli lipopolysaccharide (LPS) 6 mg kg−1 intravenously (i.v.) for 6 h) and treated with vehicle (saline, 1 ml kg−1 i.v.) or DL-propargylglycine (PAG, 10–100 mg kg−1 i.v.), an inhibitor of the H2S-synthesizing enzyme cystathionine-γ-lyase (CSE). PAG was administered either 30 min prior to or 60 min after the induction of endotoxemia.Endotoxemia resulted in circulatory failure (hypotension and tachycardia) and an increase in serum levels of alanine aminotransferase and aspartate aminotransferase (markers for hepatic injury), lipase (indicator of pancreatic injury) and creatine kinase (indicator of neuromuscular injury). In the liver, endotoxemia induced a significant increase in the myeloperoxidase (MPO) activity, and in the expression and activity of the H2S-synthesizing enzymes CSE and cystathionine-β-synthase.Administration of PAG either prior to or after the injection of LPS dose-dependently reduced the hepatocellular, pancreatic and neuromuscular injury caused by endotoxemia, but not the circulatory failure. Pretreatment of rats with PAG abolished the LPS-induced increase in the MPO activity and in the formation of H2S and in the liver.These findings support the view that an enhanced formation of H2S contributes to the pathophysiology of the organ injury in endotoxemia. We propose that inhibition of H2S synthesis may be a useful therapeutic strategy against the organ injury associated with sepsis and shock.British Journal of Pharmacology (2005) 146, 498–505. doi:10.1038/sj.bjp.0706367; published online 15 August 2005 [ABSTRACT FROM AUTHOR]

Gases such as nitric oxide (NO) and carbon monoxide (CO) play important roles both in normal physiology and in disease. The toxic effects of hydrogen sulphide (H 2 S) on living organisms have been recognized for nearly 300 years. In recent years, however, interest has been directed towards H 2 S as the third gaseous mediator, which has been shown to exhibit potent vasodilator activity both in vitro and in vivo most probably by opening vascular smooth muscle K ATP channels. Of the two enzymes, cystathionine-γ-lyase (CSE) and cystathionine-β-synthetase (CBS), which utilize L-cysteine as substrate to form H 2 S, CSE is believed to be the key enzyme which forms H 2 S in the cardiovascular system. Recent studies have shown an important role of the vasodilator action of H 2 S in health and disease. IUBMB Life , 57: 603–606, 2005 [ABSTRACT FROM AUTHOR]

Hydrogen sulphide (H2S) is a naturally occurring gas, with potent vasodilator activity. In this report, we identify a role for H2S in carrageenan-induced hindpaw oedema in the rat. Intraplantar injection of carrageenan (150?µl, 2%(w?v-1)) resulted in an increase in hindpaw H2S synthesising enzyme activity and increased myeloperoxidase (MPO) activity. Pretreatment (i.p. 60?min before carrageenan) with DL-propargylglycine (PAG, 25-75?mg?kg-1), an inhibitor of the H2S synthesising enzyme cystathionine-?-lyase (CSE), significantly reduced carrageenan-induced hindpaw oedema in a dose-dependent manner (e.g. increase in hindpaw weight at 3?h, saline: 0.12±0.017?g; carrageenan, 1.39±0.037?g; PAG, 50?mg?kg-1, 1.11±0.06?g, n=10) and MPO activity (fold increase) in the hindpaw (saline: 1.0±0.12; carrageenan, 2.92±0.45?g; PAG, 50?mg?kg-1, 1.1±0.22, n=10); PAG (50?mg?kg-1) also inhibited H2S synthesising enzyme activity (nmol?µg DNA-1) in the hindpaw in a dose-dependent manner (saline, 0.46±0.05; carrageenan, 0.71±0.08?g; PAG, 50?mg?kg-1, 0.17±0.05, n=10).British Journal of Pharmacology (2005) 145, 141-144. doi:10.1038/sj.bjp.0706186 [ABSTRACT FROM AUTHOR]

Haemorrhagic shock (60 min) in the anaesthetized rat resulted in a prolonged fall in the mean arterial blood pressure (MAP) and heart rate (HR). Pre-treatment (30 min before shock) or post-treatment (60 min after shock) with inhibitors of cystathionine gamma lyase (CSE; converts cysteine into hydrogen sulphide (H(2)S)), dl-propargylglycine or beta-cyanoalanine (50 mg kg(-1), i.v.), or glibenclamide (40 mg kg(-1), i.p.), produced a rapid, partial restoration in MAP and HR. Neither saline nor DMSO affected MAP or HR. Plasma H(2)S concentration was elevated 60 min after blood withdrawal (37.5+/-1.3 microM, n=18 c.f. 28.9+/-1.4 microM, n=15, P<0.05). The conversion of cysteine to H(2)S by liver (but not kidney) homogenates prepared from animals killed 60 min after withdrawal of blood was significantly increased (52.1+/-1.6 c.f. 39.8+/-4.1 nmol mg protein(-1), n=8, P<0.05), as was liver CSE mRNA (2.7 x). Both PAG (IC(50), 55.0+/-3.2 microM) and BCA (IC(50), 6.5+/-1.2 microM) inhibited liver H(2)S synthesizing activity in vitro. Pre-treatment of animals with PAG or BCA (50 mg kg(-1), i.p.) but not glibenclamide (40 mg kg(-1), i.p., K(ATP) channel inhibitor) abolished the rise in plasma H(2)S in animals exposed to 60 min haemorrhagic shock and prevented the augmented biosynthesis of H(2)S from cysteine in liver. These results demonstrate that H(2)S plays a role in haemorrhagic shock in the rat. CSE inhibitors may provide a novel approach to the treatment of haemorrhagic shock. [ABSTRACT FROM AUTHOR]

Provides information on a study which investigated the part played by the novel gaseous mediator, hydrogen sulfide (H2S) in Escherichia coli lipopolysaccharide-induced inflammation in the mouse. Plasma concentrations of gaseous mediator in patients with septic shock; Possible inflammatory effect of H2S; Cellular targets for H2S in LPS-mediated inflammation.

Presents a study on the role of hydrogen sulfide in acute pancreatitis and associated lung injury. Effect of the induction of acute pancreatitis in mice by caerulein hyperstimulation on plasma hydrogen sulfide levels; Gene found to be expressed by mouse pancreas; Treatment that attenuated morphological changes in acute pancreatitis.

Treatment of pancreatic acinar cells by hydrogen sulphide has been shown to induce apoptosis. However, a potential role of mitogen-activated protein kinases (MAPKs) in this apoptotic pathway remains unknown. The present study examined the role of MAPKs in H(2)S-induced apoptosis in mouse pancreatic acinar cells. Pancreatic acinar cells were treated with 10 microM NaHS (a donor of H(2)S) for 3 hrs. For the evaluation of the role of MAPKs, PD98059, SP600125 and SB203580 were used as MAPKs inhibitors for ERK1/2, JNK1/2 and p38 MAPK, respectively. We observed activation of ERK1/2, JNK1/2 and p38 when pancreatic acini were exposed to H(2)S. Moreover, H(2)S-induced ERK1/2, JNK1/2 and p38 activation were blocked by pre-treatment with their corresponding inhibitor in a dose-dependent manner. H(2)S-induced apoptosis led to an increase in caspase 3 activity and this activity was attenuated when caspase 3 inhibitor were used. Also, the cleavage of caspase 3 correlated with that of poly-(ADP-ribose)-polymerase (PARP) cleavage. H(2)S treatment induced the release of cytochrome c, smac from mitochondria into the cytoplasm, translocation of Bax into mitochondria and decreased the protein level of Bcl-2. Inhibition of ERK1/2 using PD98059 caused further enhancement of apoptosis as evidenced by annexin V staining, while SP600125 and SB203580 abrogated H(2)S-induced apoptosis. Taken together, the data suggest that activation of ERKs promotes cell survival, whereas activation of JNKs and p38 MAP kinase leads to H(2)S-induced apoptosis.

Hydrogen sulphide (H(2)S) is synthesized from L-cysteine via the action of cystathionine-gamma-lyase (CSE) and cystathionine-beta-synthase (CBS). We have earlier shown that H(2)S acts as a mediator of inflammation. However the mechanism remains unclear. In this study, we investigated the presence of H(2)S and the expression of H(2)S synthesizing enzymes, CSE and CBS, in isolated mouse pancreatic acini. Pancreatic acinar cells from mice were incubated with or without caerulein (10(-7) M for 30 and 60 min). Caerulein increased the levels of H(2)S and CSE mRNA expression while CBS mRNA expression was decreased. In addition, cells pre-treated with DL-propargylglycine (PAG, 3 mM), a CSE inhibitor, reduced the formation of H(2)S in caerulein treated cells, suggesting that CSE may be the main enzyme involved in H(2)S formation in mouse acinar cells. Furthermore, substance P (SP) concentration in the acini and expression of SP gene (preprotachykinin-A, PPT-A) and neurokinin-1 receptor (NK-1R), the primary receptor for SP, are increased in secretagogue caerulein-treated acinar cells. Inhibition of endogenous production of H(2)S by PAG significantly suppressed SP concentration, PPT-A expression and NK1-R expression in the acini. To determine whether H(2)S itself provoked inflammation in acinar cells, the cells were treated with H(2)S donor drug, sodium hydrosulphide (NaHS), (10, 50 and 100 muM), that resulted in a significant increase in SP concentration and expression of PPT-A and NK1-R in acinar cells. These results suggest that the pro-inflammatory effect of H(2)S may be mediated by SP-NK-1R related pathway in mouse pancreatic acinar cells.