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Systemic infection and combined burn and infection: Contribution of host-derived and bacteria-derived hydrogen sulfide production to bacterial clearance
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Abstracts/Nitric Oxide 47 (2015) S14–S60
tion of pro-inflammatory gene expression occurred by modulation of activation of the key transcription factors NF-κB and IRF-3. Compared to RSV-infected WT mice, RSV-infected CSE−/− mice exhibited a significant increase in AHR to methacholine challenge and surprisingly showed increased peak viral replication in the lung (p < 0.005). CSE−/− mice also displayed increased lung pathology, compared to WT mice. To further test the role of H2S in the context of viral infection we treated groups of 10–11 week-old BALB/c mice with the H 2 S donor GYY4137. Intranasal delivery of GYY4137 (50 mg/kg) to RSV-inoculated mice markedly improved disease parameters and reduced viral replication in the lungs compared to untreated controls. The protective effects of H2S were associated with a significant reduction of viral-induced inflammatory cytokines, as well as lung inflammation Conclusions: Overall these results indicate that H2S exerts a novel antiviral activity in the lung and controls airway responsiveness and inflammatory signals that affect cytokine production in response to a clinical relevant human pathogen. http://dx.doi.org/10.1016/j.niox.2015.02.110
PP81 Hydrogen sulfide in lung adenocarcinoma: A tumor cell survival factor, an enhancer of mitochondrial DNA repair and a cellular bioenergetic stimulator Bartosz Szczesny a, Attila Brunyanszki a, Mark R. Hellmich b, Csaba Szabo a a Department of Anesthesiology, The University of Texas Medical Branch, Galveston, TX, USA b Department of Surgery, The University of Texas Medical Branch, Galveston, TX, USA Introduction: According to the American Cancer Society, in 2014, 224,000 new lung cancer cases and 160,000 deaths caused by lung cancer were expected in the US, accounting for approximately 28% of all cancer-related deaths; more than for the next three most common cancers combined (colon, breast and prostate). H2S is recently receiving significant attention as an important pathological factor in various cancers. We have shown that an intramitochondrial process, driven by cystathionine-beta-synthase (CBS), produces H2S from L-cysteine, which, in turn, drives oxidative phosphorylation and promotes cellular bioenergetics in colorectal tumor cells. Similar findings, implicating CBS, were subsequently reported in ovarian cancer. Others have demonstrated the upregulation of other H2Sproducing enzymes, including cystathionine-gamma-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (3-MST) in various forms of cancer. In several studies, inhibition of H2S production results in an inhibition of tumor cell proliferation in vitro, and in significant antitumor effects in vivo. However, the role of H2S and H2S-producing enzymes in lung cancer has not been explored, and this was the aim of the current study. Results: We investigated the potential importance of H2S metabolism in lung adenocarcinoma and lung adenocarcinomaderived cells. Using various biochemical methods we found that: a) the expression of all three H 2 S-generating enzymes, namely, CBS, CSE, and 3-MST, was upregulated in human lung tumor biopsies and lung adenocarcinoma derived cells (A549) when compared to their respective normal counterpart; b) inhibition of H2S production induced the selective accumulation of mitochondrial (but not nuclear) DNA damage in A549 cells but not in non-tumorigenic lung epithelial cells (BEAS 2B); c) pharmacological inhibition of H2S production sensitized mitochondrial DNA to oxidant-induced damage and negatively affected the repair of the mitochondrial DNA; d) siRNA-mediated silencing of
CSE, followed by bioenergetic analysis (Seahorse extracellular flux analysis) showed that CSE-derived H2S is essential for mitochondrial bioenergetics of A549 cells (but not of BEAS 2B cells); and e) A549 cells were more sensitive to pharmacological inhibition of H2S production than BEAS 2B cells. Conclusions: We conclude that H2S production in the A549 lung adenocarcinoma cell, predominantly from CSE, plays a vital role in maintaining mitochondrial functions, namely, DNA repair and bioenergetics. We hypothesize that via these mechanisms H2S may provide a proliferative and survival advantage to these cells. http://dx.doi.org/10.1016/j.niox.2015.02.111
PP82 Systemic infection and combined burn and infection: Contribution of host-derived and bacteria-derived hydrogen sulfide production to bacterial clearance Tracy Toliver-Kinsky a,b, Konstantin Shatalin c, Evgeny Nudler c, Csaba Szabo a,b a Department of Anesthesiology, The University of Texas Medical Branch, Galveston, TX, USA b Shriners Hospital for Children, Galveston, TX, USA c Howard Hughes Medical Institute, Department of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, NY, USA Introduction: Patients suffering severe traumas such as burn injury are susceptible to opportunistic infections that delay healing and increase morbidity and mortality. Development of interventions to safely prevent or treat infections in trauma patients would improve outcome after injury. Hydrogen sulfide (H2S) has been shown to mediate numerous biological functions in mammals, including some immune functions, but its role in antimicrobial responses during infection remains to be fully determined. H2S is also produced by bacteria and has been shown to regulate bacterial proliferation and antibacterial resistance in vitro. However, its contribution to infectivity in vivo has not yet been determined. The purpose of this study was to examine the roles of host- and bacteria-derived H2S production in bacterial clearance during infection in the absence or presence of concomitant burn injury. Results: To prevent host production of H2S, mice were treated with the cystathionine-β-synthase (CBS) inhibitor aminooxyacetic acid (AOAA, 10 mg/kg) 24 hours and 30 minutes prior to infection with either Pseudomonas aeruginosa or Escherichia coli. Additionally, IFN-γ production in response to challenge with heat-killed bacteria was measured in plasma and in media of splenocytes treated with AOAA (1 mM) or its vehicle. Following bacterial infection in vivo, AOAA treatment significantly reduced the degree of bacteremia, indicating that AOAA improved the clearance of both bacterial strains. The effects of AOAA in vivo were associated with decreased systemic IFN-γ production. When splenocytes were stimulated with heat-killed bacteria, AOAA also reduced IFN-γ production. The results of our IFN-γ measurements suggest that AOAA increases bacterial clearance via mechanisms other than enhanced Th1 responses. To determine the role of bacteria-derived H2S in resistance to host antimicrobial mechanisms, mice were infected either with wild-type E. coli or with mutant E. coli with a deficiency in H2S production due to deletion of 3-mercaptopyruvate sulfurtransferase (3-MST). Bacterial burden was significantly lower in the blood of mice infected with the 3-MSTdeficient strain, compared to those infected with wild-type bacteria. These results indicate that bacteria-derived H2S contributes to infectivity of E. coli in vivo. Even when 3-MST-deficient bacteria were used to infect the host, treatment of the host with AOAA afforded an additional reduction in bacterial burden. To extend the find-
Abstracts/Nitric Oxide 47 (2015) S14–S60
ings to the pathophysiology of burn, mice were subjected to scald burn injury (35% total surface area), followed by infection with P. aeruginosa. Bacterial cultures were performed to assess bacterial clearance. Consistent with previous reports, bacterial counts were significantly higher in burned mice, compared to sham-injured mice, indicating that burn markedly impairs bacterial clearance. Similar to mice without burns, AOAA reduced bacterial counts in burninjured mice. As previously reported, IFN-γ production in response to heat-killed bacteria was decreased after burn injury. In contrast to sham mice, where AOAA decreased IFN-γ production, AOAA did not further decrease IFN-γ levels in burned mice. Also in mice with burns, bacterial burden was markedly lower when 3-MST deficient bacteria were used for the infection; moreover, AOAA decreased bacterial burden in burn animals infected either with wild-type or with 3-MST-deficient bacteria. Conclusions: These data demonstrate that both bacteria-derived H2S production and host-derived H2S production regulate bacterial clearance in vivo. Inhibition of host H 2 S production and/or inhibition of bacterial H2S production may be a potential approach to reduce bacterial burden during infections. This approach may be especially valuable during burns, when the ability of the host to clear bacterial infection is markedly impaired. http://dx.doi.org/10.1016/j.niox.2015.02.112
PP83 Downregulation of hydrogen sulfide in mice exposed to cigarette smoke Sofia-Iris Bibli a, Constantinos Glynos b, Athanasia Chatzianastasiou b, Efstathios K. Iliodromitis c, Ioanna Andreadou a, Andreas Papapetropoulos a a Faculty of Pharmacy, University of Athens, Greece b “George P. Livanos and Marianthi Simou” Laboratories, Evangelismos Hospital, 1st Department of Pulmonary and Critical Care, Faculty of Medicine, University of Athens, Greece c Faculty of Medicine, Second Department of Cardiology, Attikon University Hospital, University of Athens, Greece Background: Recent evidence supports a pivotal role for H2S in a variety of physiological and pathophysiological conditions. In the cardiovascular system, H2S promotes angiogenesis, regulates blood pressure, exhibits cardioprotective actions, reduces endothelial dysfunction, limits atherosclerosis and exerts anti-inflammatory and anti-oxidant effects. Aim: Cigarette smoking (CS) is a major independent risk factor for cardiovascular disease. To date, no study has addressed the effect of CS on the H2S pathway. Herein, we established a murine model of passive smoking, evaluated hemodynamic variables and response to myocardial ischemia (I)/reperfusion (R) injury and correlated them to alterations in the expression of the H2S and NO generating enzymes. Methods: C57/BL6 male mice were divided in 2 groups. The CS group was exposed to cigarette smoke from reference cigarettes (3R4F University of Kentucky, USA), 4 times a day for 4 weeks. The Control group was exposed to room air (RA). Blood and tissue samples from myocardium and arteries (aorta and carotid) of both groups were obtained for analysis. Protein levels of cystathionine-β-synthase (CBS), cystathionine-γ-lyase (CSE), 3-mercaptopyruvate sulfurtransferase (MPST), endothelial nitric oxide (NO) synthase (eNOS), inducible NO synthase (iNOS) and soluble guanylyl cyclase (sGC) were evaluated by western blotting. Oxidative stress markers (malondialdehyde and protein carbonyls) were also measured. H2S levels were determined using the methylene blue assay. In a second series of experiments electrocardiogram was recorded and the left carotid was
S47
catheterized for mean arterial pressure (MAP) measurement by a fluid filed transducer. Following the recording, animals were subjected to 30 min–2 h regional myocardial I/R and the infarcted/ risk area was estimated by Evans blue-TTC staining. Results: The expression of CBS and CSE, but not MPST, was significantly reduced in the hearts, aortas and carotids of CS mice. In contrast, levels of eNOS, iNOS and sGC subunits (α1/β1) were increased in the heart. In line with the observed reduction in CBS and CSE, H2S levels in plasma and heart homogenates were lower in the CS group. No differences in the levels of malondialdehyde and protein carbonyls were observed in the heart. Exposure to CS increased heart/ body weight compared to RA animals. In addition, in CS mice we observed a taller R-Wave, a deeper S-Wave and an increased QRS amplitude, indicative of cardiac hypertrophy. MAP was increased from 107 mmHg in RA to 193 mmHg in CS animals. Heart rate before any surgical procedure was not different among groups. Finally, exposure to CS did not increase the infarcted/risk area in the heart (38.3 ± 3.6% vs 40.9 ± 2.2% for CS and RA). Conclusions: Exposure to cigarette smoke differentially regulates H2S and NO synthetizing enzymes in the cardiovascular system. These changes in gasotransmitter levels coincide with an increase in cardiac mass and blood pressure. Restoration of H2S production might be useful in offsetting some of the detrimental effects of smoking in the heart and vessels. This work has been funded by Greek national funds through the Operational Program "Education and Lifelong Learning" of the National Strategic Reference Framework (NSRF) – Research Funding Program: Aristeia 2011 (1436). http://dx.doi.org/10.1016/j.niox.2015.02.113
PP84 Hydrogen sulfide inhibits hydrogen peroxide-induced senescence of human umbilical vascular endothelial cells through activation of the SIRT1/FoxO1 pathway Xin-Yuan Luo a, Zhi-Han Tang a, Shun-Lin Qu a, Juan Peng a, Hui Tang a, Zhong Ren a, Xia-Qing Ren a, Wei-Jin Xiao a, Yu Gui b, Xi-Long Zheng b, Zhi-Sheng Jiang a a Institute of Cardiovascular Disease and Key Lab for Arteriosclerology of Hunan Province, University of South China, Hengyang City, Hunan Province, China b The Smooth Muscle Research Group, Department of Physiology and Pharmacology, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada Background and objective: Aging is a key independent risk factor for cardiovascular disease. It has been reported that hydrogen sulfide (H2S) has an inhibitory effect on aging, but the underlying mechanisms remain largely unclear. SIRT1, a highly conserved NAD+dependent protein deacetylase, functions as a longevity factor through deacetylating FoxO1 to increase the resistance to oxidative stress and retard aging. This study aimed to explore whether activation of SIRT1/FoxO1 signaling is involved in H2S-inhibited senescence of human umbilical vascular endothelial cells (HUVECs) induced by hydrogen peroxide (H2O2). Methods and results: The senescence of HUVECs was induced by treatment with 100 μM H2O2 for 1 h. The SA-β-gal activity in the H2O2-treated HUVECs was increased by 8.4 fold, compared with that in the control group (p < 0.01). The expressions of p53, p21 and plasminogen activator inhibitor-1 (PAI-1) in the H2O2treated group, as detected by western blot analysis, were obviously enhanced by 60.5%, 581.9% and 166.5%, respectively, compared with those in the control group (p < 0.01). Pretreatment of HUVECs with 100 μM NaHS for 30 min significantly inhibited
Abstracts/Nitric Oxide 47 (2015) S14–S60
tion of pro-inflammatory gene expression occurred by modulation of activation of the key transcription factors NF-κB and IRF-3. Compared to RSV-infected WT mice, RSV-infected CSE−/− mice exhibited a significant increase in AHR to methacholine challenge and surprisingly showed increased peak viral replication in the lung (p < 0.005). CSE−/− mice also displayed increased lung pathology, compared to WT mice. To further test the role of H2S in the context of viral infection we treated groups of 10–11 week-old BALB/c mice with the H 2 S donor GYY4137. Intranasal delivery of GYY4137 (50 mg/kg) to RSV-inoculated mice markedly improved disease parameters and reduced viral replication in the lungs compared to untreated controls. The protective effects of H2S were associated with a significant reduction of viral-induced inflammatory cytokines, as well as lung inflammation Conclusions: Overall these results indicate that H2S exerts a novel antiviral activity in the lung and controls airway responsiveness and inflammatory signals that affect cytokine production in response to a clinical relevant human pathogen. http://dx.doi.org/10.1016/j.niox.2015.02.110
PP81 Hydrogen sulfide in lung adenocarcinoma: A tumor cell survival factor, an enhancer of mitochondrial DNA repair and a cellular bioenergetic stimulator Bartosz Szczesny a, Attila Brunyanszki a, Mark R. Hellmich b, Csaba Szabo a a Department of Anesthesiology, The University of Texas Medical Branch, Galveston, TX, USA b Department of Surgery, The University of Texas Medical Branch, Galveston, TX, USA Introduction: According to the American Cancer Society, in 2014, 224,000 new lung cancer cases and 160,000 deaths caused by lung cancer were expected in the US, accounting for approximately 28% of all cancer-related deaths; more than for the next three most common cancers combined (colon, breast and prostate). H2S is recently receiving significant attention as an important pathological factor in various cancers. We have shown that an intramitochondrial process, driven by cystathionine-beta-synthase (CBS), produces H2S from L-cysteine, which, in turn, drives oxidative phosphorylation and promotes cellular bioenergetics in colorectal tumor cells. Similar findings, implicating CBS, were subsequently reported in ovarian cancer. Others have demonstrated the upregulation of other H2Sproducing enzymes, including cystathionine-gamma-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (3-MST) in various forms of cancer. In several studies, inhibition of H2S production results in an inhibition of tumor cell proliferation in vitro, and in significant antitumor effects in vivo. However, the role of H2S and H2S-producing enzymes in lung cancer has not been explored, and this was the aim of the current study. Results: We investigated the potential importance of H2S metabolism in lung adenocarcinoma and lung adenocarcinomaderived cells. Using various biochemical methods we found that: a) the expression of all three H 2 S-generating enzymes, namely, CBS, CSE, and 3-MST, was upregulated in human lung tumor biopsies and lung adenocarcinoma derived cells (A549) when compared to their respective normal counterpart; b) inhibition of H2S production induced the selective accumulation of mitochondrial (but not nuclear) DNA damage in A549 cells but not in non-tumorigenic lung epithelial cells (BEAS 2B); c) pharmacological inhibition of H2S production sensitized mitochondrial DNA to oxidant-induced damage and negatively affected the repair of the mitochondrial DNA; d) siRNA-mediated silencing of
CSE, followed by bioenergetic analysis (Seahorse extracellular flux analysis) showed that CSE-derived H2S is essential for mitochondrial bioenergetics of A549 cells (but not of BEAS 2B cells); and e) A549 cells were more sensitive to pharmacological inhibition of H2S production than BEAS 2B cells. Conclusions: We conclude that H2S production in the A549 lung adenocarcinoma cell, predominantly from CSE, plays a vital role in maintaining mitochondrial functions, namely, DNA repair and bioenergetics. We hypothesize that via these mechanisms H2S may provide a proliferative and survival advantage to these cells. http://dx.doi.org/10.1016/j.niox.2015.02.111
PP82 Systemic infection and combined burn and infection: Contribution of host-derived and bacteria-derived hydrogen sulfide production to bacterial clearance Tracy Toliver-Kinsky a,b, Konstantin Shatalin c, Evgeny Nudler c, Csaba Szabo a,b a Department of Anesthesiology, The University of Texas Medical Branch, Galveston, TX, USA b Shriners Hospital for Children, Galveston, TX, USA c Howard Hughes Medical Institute, Department of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, NY, USA Introduction: Patients suffering severe traumas such as burn injury are susceptible to opportunistic infections that delay healing and increase morbidity and mortality. Development of interventions to safely prevent or treat infections in trauma patients would improve outcome after injury. Hydrogen sulfide (H2S) has been shown to mediate numerous biological functions in mammals, including some immune functions, but its role in antimicrobial responses during infection remains to be fully determined. H2S is also produced by bacteria and has been shown to regulate bacterial proliferation and antibacterial resistance in vitro. However, its contribution to infectivity in vivo has not yet been determined. The purpose of this study was to examine the roles of host- and bacteria-derived H2S production in bacterial clearance during infection in the absence or presence of concomitant burn injury. Results: To prevent host production of H2S, mice were treated with the cystathionine-β-synthase (CBS) inhibitor aminooxyacetic acid (AOAA, 10 mg/kg) 24 hours and 30 minutes prior to infection with either Pseudomonas aeruginosa or Escherichia coli. Additionally, IFN-γ production in response to challenge with heat-killed bacteria was measured in plasma and in media of splenocytes treated with AOAA (1 mM) or its vehicle. Following bacterial infection in vivo, AOAA treatment significantly reduced the degree of bacteremia, indicating that AOAA improved the clearance of both bacterial strains. The effects of AOAA in vivo were associated with decreased systemic IFN-γ production. When splenocytes were stimulated with heat-killed bacteria, AOAA also reduced IFN-γ production. The results of our IFN-γ measurements suggest that AOAA increases bacterial clearance via mechanisms other than enhanced Th1 responses. To determine the role of bacteria-derived H2S in resistance to host antimicrobial mechanisms, mice were infected either with wild-type E. coli or with mutant E. coli with a deficiency in H2S production due to deletion of 3-mercaptopyruvate sulfurtransferase (3-MST). Bacterial burden was significantly lower in the blood of mice infected with the 3-MSTdeficient strain, compared to those infected with wild-type bacteria. These results indicate that bacteria-derived H2S contributes to infectivity of E. coli in vivo. Even when 3-MST-deficient bacteria were used to infect the host, treatment of the host with AOAA afforded an additional reduction in bacterial burden. To extend the find-
Abstracts/Nitric Oxide 47 (2015) S14–S60
ings to the pathophysiology of burn, mice were subjected to scald burn injury (35% total surface area), followed by infection with P. aeruginosa. Bacterial cultures were performed to assess bacterial clearance. Consistent with previous reports, bacterial counts were significantly higher in burned mice, compared to sham-injured mice, indicating that burn markedly impairs bacterial clearance. Similar to mice without burns, AOAA reduced bacterial counts in burninjured mice. As previously reported, IFN-γ production in response to heat-killed bacteria was decreased after burn injury. In contrast to sham mice, where AOAA decreased IFN-γ production, AOAA did not further decrease IFN-γ levels in burned mice. Also in mice with burns, bacterial burden was markedly lower when 3-MST deficient bacteria were used for the infection; moreover, AOAA decreased bacterial burden in burn animals infected either with wild-type or with 3-MST-deficient bacteria. Conclusions: These data demonstrate that both bacteria-derived H2S production and host-derived H2S production regulate bacterial clearance in vivo. Inhibition of host H 2 S production and/or inhibition of bacterial H2S production may be a potential approach to reduce bacterial burden during infections. This approach may be especially valuable during burns, when the ability of the host to clear bacterial infection is markedly impaired. http://dx.doi.org/10.1016/j.niox.2015.02.112
PP83 Downregulation of hydrogen sulfide in mice exposed to cigarette smoke Sofia-Iris Bibli a, Constantinos Glynos b, Athanasia Chatzianastasiou b, Efstathios K. Iliodromitis c, Ioanna Andreadou a, Andreas Papapetropoulos a a Faculty of Pharmacy, University of Athens, Greece b “George P. Livanos and Marianthi Simou” Laboratories, Evangelismos Hospital, 1st Department of Pulmonary and Critical Care, Faculty of Medicine, University of Athens, Greece c Faculty of Medicine, Second Department of Cardiology, Attikon University Hospital, University of Athens, Greece Background: Recent evidence supports a pivotal role for H2S in a variety of physiological and pathophysiological conditions. In the cardiovascular system, H2S promotes angiogenesis, regulates blood pressure, exhibits cardioprotective actions, reduces endothelial dysfunction, limits atherosclerosis and exerts anti-inflammatory and anti-oxidant effects. Aim: Cigarette smoking (CS) is a major independent risk factor for cardiovascular disease. To date, no study has addressed the effect of CS on the H2S pathway. Herein, we established a murine model of passive smoking, evaluated hemodynamic variables and response to myocardial ischemia (I)/reperfusion (R) injury and correlated them to alterations in the expression of the H2S and NO generating enzymes. Methods: C57/BL6 male mice were divided in 2 groups. The CS group was exposed to cigarette smoke from reference cigarettes (3R4F University of Kentucky, USA), 4 times a day for 4 weeks. The Control group was exposed to room air (RA). Blood and tissue samples from myocardium and arteries (aorta and carotid) of both groups were obtained for analysis. Protein levels of cystathionine-β-synthase (CBS), cystathionine-γ-lyase (CSE), 3-mercaptopyruvate sulfurtransferase (MPST), endothelial nitric oxide (NO) synthase (eNOS), inducible NO synthase (iNOS) and soluble guanylyl cyclase (sGC) were evaluated by western blotting. Oxidative stress markers (malondialdehyde and protein carbonyls) were also measured. H2S levels were determined using the methylene blue assay. In a second series of experiments electrocardiogram was recorded and the left carotid was
S47
catheterized for mean arterial pressure (MAP) measurement by a fluid filed transducer. Following the recording, animals were subjected to 30 min–2 h regional myocardial I/R and the infarcted/ risk area was estimated by Evans blue-TTC staining. Results: The expression of CBS and CSE, but not MPST, was significantly reduced in the hearts, aortas and carotids of CS mice. In contrast, levels of eNOS, iNOS and sGC subunits (α1/β1) were increased in the heart. In line with the observed reduction in CBS and CSE, H2S levels in plasma and heart homogenates were lower in the CS group. No differences in the levels of malondialdehyde and protein carbonyls were observed in the heart. Exposure to CS increased heart/ body weight compared to RA animals. In addition, in CS mice we observed a taller R-Wave, a deeper S-Wave and an increased QRS amplitude, indicative of cardiac hypertrophy. MAP was increased from 107 mmHg in RA to 193 mmHg in CS animals. Heart rate before any surgical procedure was not different among groups. Finally, exposure to CS did not increase the infarcted/risk area in the heart (38.3 ± 3.6% vs 40.9 ± 2.2% for CS and RA). Conclusions: Exposure to cigarette smoke differentially regulates H2S and NO synthetizing enzymes in the cardiovascular system. These changes in gasotransmitter levels coincide with an increase in cardiac mass and blood pressure. Restoration of H2S production might be useful in offsetting some of the detrimental effects of smoking in the heart and vessels. This work has been funded by Greek national funds through the Operational Program "Education and Lifelong Learning" of the National Strategic Reference Framework (NSRF) – Research Funding Program: Aristeia 2011 (1436). http://dx.doi.org/10.1016/j.niox.2015.02.113
PP84 Hydrogen sulfide inhibits hydrogen peroxide-induced senescence of human umbilical vascular endothelial cells through activation of the SIRT1/FoxO1 pathway Xin-Yuan Luo a, Zhi-Han Tang a, Shun-Lin Qu a, Juan Peng a, Hui Tang a, Zhong Ren a, Xia-Qing Ren a, Wei-Jin Xiao a, Yu Gui b, Xi-Long Zheng b, Zhi-Sheng Jiang a a Institute of Cardiovascular Disease and Key Lab for Arteriosclerology of Hunan Province, University of South China, Hengyang City, Hunan Province, China b The Smooth Muscle Research Group, Department of Physiology and Pharmacology, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada Background and objective: Aging is a key independent risk factor for cardiovascular disease. It has been reported that hydrogen sulfide (H2S) has an inhibitory effect on aging, but the underlying mechanisms remain largely unclear. SIRT1, a highly conserved NAD+dependent protein deacetylase, functions as a longevity factor through deacetylating FoxO1 to increase the resistance to oxidative stress and retard aging. This study aimed to explore whether activation of SIRT1/FoxO1 signaling is involved in H2S-inhibited senescence of human umbilical vascular endothelial cells (HUVECs) induced by hydrogen peroxide (H2O2). Methods and results: The senescence of HUVECs was induced by treatment with 100 μM H2O2 for 1 h. The SA-β-gal activity in the H2O2-treated HUVECs was increased by 8.4 fold, compared with that in the control group (p < 0.01). The expressions of p53, p21 and plasminogen activator inhibitor-1 (PAI-1) in the H2O2treated group, as detected by western blot analysis, were obviously enhanced by 60.5%, 581.9% and 166.5%, respectively, compared with those in the control group (p < 0.01). Pretreatment of HUVECs with 100 μM NaHS for 30 min significantly inhibited