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HO-1 Limits the Efficacy of Vemurafenib/PLX4032 in BRAF V600E Mutated Melanoma Cells Adapted to Physiological Normoxia or Hypoxia. Antioxidants (Basel) 2022; 11:antiox11061171. [PMID: 35740068 PMCID: PMC9219655 DOI: 10.3390/antiox11061171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 06/08/2022] [Accepted: 06/10/2022] [Indexed: 02/04/2023] Open
Abstract
Induction of heme oxygenase 1 (HO-1) favors immune-escape in BRAFV600 melanoma cells treated with Vemurafenib/PLX4032 under standard cell culture conditions. However, the oxygen tension under standard culture conditions (~18 kPa O2) is significantly higher than the physiological oxygen levels encountered in vivo. In addition, cancer cells in vivo are often modified by hypoxia. In this study, MeOV-1 primary melanoma cells bearing the BRAFV600E mutation, were adapted to either 5 kPa O2 (physiological normoxia) or 1 kPa O2 (hypoxia) and then exposed to 10 μM PLX4032. PLX4032 abolished ERK phosphorylation, reduced Bach1 expression and increased HO-1 levels independent of pericellular O2 tension. Moreover, cell viability was significantly reduced further in cells exposed to PLX4032 plus Tin mesoporphyrin IX, a HO-1 inhibitor. Notably, our findings provide the first evidence that HO-1 inhibition in combination with PLX4032 under physiological oxygen tension and hypoxia restores and increases the expression of the NK ligands ULBP3 and B7H6 compared to cells exposed to PLX4032 alone. Interestingly, although silencing NRF2 prevented PLX4032 induction of HO-1, other NRF2 targeted genes were unaffected, highlighting a pivotal role of HO-1 in melanoma resistance and immune escape. The present findings may enhance translation and highlight the potential of the HO-1 inhibitors in the therapy of BRAFV600 melanomas.
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Chase LA, VerHeulen Kleyn M, Schiller N, King AG, Flores G, Engelsman SB, Bowles C, Smith SL, Robinson AE, Rothstein J. Hydrogen peroxide triggers an increase in cell surface expression of system x c- in cultured human glioma cells. Neurochem Int 2019; 134:104648. [PMID: 31874187 DOI: 10.1016/j.neuint.2019.104648] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 12/15/2019] [Accepted: 12/18/2019] [Indexed: 12/14/2022]
Abstract
System xc- exchanges extracellular cystine for intracellular glutamate across the plasma membrane of many cell types. One of the physiological roles of System xc- is to provide cystine for synthesis of the antioxidant glutathione. Here we report that hydrogen peroxide (H2O2) triggers the translocation of System xc- to the plasma membrane within 10 min of the initial exposure. Specifically, we observed a three-fold increase in 35S-l-cystine uptake following a 10 min exposure to 0.3 mM H2O2. This effect was dose-dependent with an EC50 for H2O2 of 65 μM. We then used cell surface biotinylation analysis to test the hypothesis that the increase in activity is due to an increased number of transporters on the plasma membrane. We demonstrated that the amount of transporter protein, xCT, localized to the plasma membrane doubles within 10 min of H2O2 exposure as a result of an increase in its delivery rate and a reduction in its internalization rate. In addition, we demonstrated that H2O2 triggered a rapid decrease in total cellular glutathione which recovered within 2 h of the oxidative insult. The kinetics of glutathione recovery matched the time course for the recovery of xCT cell surface expression and System xc- activity following removal of the oxidative insult. Collectively, these results suggest that oxidants acutely modulate the activity of System xc- by increasing its cell surface expression, and that this process may serve as an important mechanism to increase de novo glutathione synthesis during periods of oxidative stress.
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Affiliation(s)
- Leah A Chase
- Department of Chemistry, Hope College, Holland, MI, 49423, USA; Department of Biology, Hope College, Holland, MI, 49423, USA.
| | | | - NaTasha Schiller
- Department of Chemistry, Hope College, Holland, MI, 49423, USA; Department of Biology, Hope College, Holland, MI, 49423, USA
| | - Abby Goltz King
- Department of Chemistry, Hope College, Holland, MI, 49423, USA
| | - Guillermo Flores
- Department of Chemistry, Hope College, Holland, MI, 49423, USA; Department of Biology, Hope College, Holland, MI, 49423, USA
| | | | | | - Sara Lang Smith
- Department of Biology, Hope College, Holland, MI, 49423, USA
| | - Anne E Robinson
- Department of Chemistry, Hope College, Holland, MI, 49423, USA; Department of Biology, Hope College, Holland, MI, 49423, USA
| | - Jeffrey Rothstein
- Department of Neurology, Department of Neuroscience, Johns Hopkins University, Baltimore, MD, 21287, USA
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Chapple SJ, Keeley TP, Mastronicola D, Arno M, Vizcay-Barrena G, Fleck R, Siow RCM, Mann GE. Bach1 differentially regulates distinct Nrf2-dependent genes in human venous and coronary artery endothelial cells adapted to physiological oxygen levels. Free Radic Biol Med 2016; 92:152-162. [PMID: 26698668 DOI: 10.1016/j.freeradbiomed.2015.12.013] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 12/11/2015] [Accepted: 12/12/2015] [Indexed: 12/18/2022]
Abstract
The effects of physiological oxygen tension on Nuclear Factor-E2-Related Factor 2 (Nrf2)-regulated redox signaling remain poorly understood. We report the first study of Nrf2-regulated signaling in human primary endothelial cells (EC) adapted long-term to physiological O2 (5%). Adaptation of EC to 5% O2 had minimal effects on cell ultrastructure, viability, basal redox status or HIF1-α expression. Affymetrix array profiling and subsequent qPCR/protein validation revealed that induction of select Nrf2 target genes, HO-1 and NQO1, was significantly attenuated in cells adapted to 5% O2, despite nuclear accumulation and DNA binding of Nrf2. Diminished HO-1 induction under 5% O2 was stimulus independent and reversible upon re-adaptation to air or silencing of the Nrf2 repressor Bach1, notably elevated under 5% O2. Induction of GSH-related genes xCT and GCLM were oxygen and Bach1-insensitive during long-term culture under 5% O2, providing the first evidence that genes related to GSH synthesis mediate protection afforded by Nrf2-Keap1 defense pathway in cells adapted to physiological O2 levels encountered in vivo.
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Affiliation(s)
- Sarah J Chapple
- Cardiovascular Division, British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London SE1 9NH, UK
| | - Thomas P Keeley
- Cardiovascular Division, British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London SE1 9NH, UK
| | - Daniela Mastronicola
- Cardiovascular Division, British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London SE1 9NH, UK
| | - Matthew Arno
- Genomics Centre, King's College London, 150 Stamford Street, London SE1 9NH, UK
| | - Gema Vizcay-Barrena
- Centre for Ultrastructural Imaging, King's College London, London SE1 9NH, UK
| | - Roland Fleck
- Centre for Ultrastructural Imaging, King's College London, London SE1 9NH, UK
| | - Richard C M Siow
- Cardiovascular Division, British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London SE1 9NH, UK
| | - Giovanni E Mann
- Cardiovascular Division, British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London SE1 9NH, UK.
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4
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N-acetylcysteine stimulates protein synthesis in enterocytes independently of glutathione synthesis. Amino Acids 2015; 48:523-33. [DOI: 10.1007/s00726-015-2105-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Accepted: 09/22/2015] [Indexed: 12/22/2022]
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Aye ILMH, Lager S, Ramirez VI, Gaccioli F, Dudley DJ, Jansson T, Powell TL. Increasing maternal body mass index is associated with systemic inflammation in the mother and the activation of distinct placental inflammatory pathways. Biol Reprod 2014; 90:129. [PMID: 24759787 DOI: 10.1095/biolreprod.113.116186] [Citation(s) in RCA: 175] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Obese pregnant women have increased levels of proinflammatory cytokines in maternal circulation and placental tissues. However, the pathways contributing to placental inflammation in obesity are largely unknown. We tested the hypothesis that maternal body mass index (BMI) was associated with elevated proinflammatory cytokines in maternal and fetal circulations and increased activation of placental inflammatory pathways. A total of 60 women of varying pre-/early pregnancy BMI, undergoing delivery by Cesarean section at term, were studied. Maternal and fetal (cord) plasma were collected for analysis of insulin, leptin, IL-1beta, IL-6, IL-8, monocyte chemoattractant protein (MCP) 1, and TNFalpha by multiplex ELISA. Activation of the inflammatory pathways in the placenta was investigated by measuring the phosphorylated and total protein expression of p38-mitogen-activated protein kinase (MAPK), c-Jun-N-terminal kinase (JNK)-MAPK, signal transducer-activated transcription factor (STAT) 3, caspase-1, IL-1beta, IkappaB-alpha protein, and p65 DNA-binding activity. To determine the link between activated placental inflammatory pathways and elevated maternal cytokines, cultured primary human trophoblast (PHT) cells were treated with physiological concentrations of insulin, MCP-1, and TNFalpha, and inflammatory signaling analyzed by Western blot. Maternal BMI was positively correlated with maternal insulin, leptin, MCP-1, and TNFalpha, whereas only fetal leptin was increased with BMI. Placental phosphorylation of p38-MAPK and STAT3, and the expression of IL-1beta protein, were increased with maternal BMI; phosphorylation of p38-MAPK was also correlated with birth weight. In contrast, placental NFkappaB, JNK and caspase-1 signaling, and fetal cytokine levels were unaffected by maternal BMI. In PHT cells, p38-MAPK was activated by MCP-1 and TNFalpha, whereas STAT3 phosphorylation was increased following TNFalpha treatment. Maternal BMI is associated with elevated maternal cytokines and activation of placental p38-MAPK and STAT3 inflammatory pathways, without changes in fetal systemic inflammatory profile. Activation of p38-MAPK by MCP-1 and TNFalpha, and STAT3 by TNFalpha, suggests a link between elevated proinflammatory cytokines in maternal plasma and activation of placental inflammatory pathways. We suggest that inflammatory processes associated with elevated maternal BMI may influence fetal growth by altering placental function.
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Affiliation(s)
- Irving L M H Aye
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, Texas
| | - Susanne Lager
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, Texas
| | - Vanessa I Ramirez
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, Texas
| | - Francesca Gaccioli
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, Texas
| | - Donald J Dudley
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, Texas
| | - Thomas Jansson
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, Texas
| | - Theresa L Powell
- Center for Pregnancy and Newborn Research, Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, Texas
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The transsulfuration pathway: a source of cysteine for glutathione in astrocytes. Amino Acids 2011; 42:199-205. [PMID: 21369939 DOI: 10.1007/s00726-011-0864-8] [Citation(s) in RCA: 163] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 02/17/2011] [Indexed: 02/06/2023]
Abstract
Astrocyte cells require cysteine as a substrate for glutamate cysteine ligase (γ-glutamylcysteine synthase; EC 6.3.2.2) catalyst of the rate-limiting step of the γ-glutamylcycle leading to formation of glutathione (L: -γ-glutamyl-L: -cysteinyl-glycine; GSH). In both astrocytes and glioblastoma/astrocytoma cells, the majority of cysteine originates from reduction of cystine imported by the x (c) (-) cystine-glutamate exchanger. However, the transsulfuration pathway, which supplies cysteine from the indispensable amino acid, methionine, has recently been identified as a significant contributor to GSH synthesis in astrocytes. The purpose of this review is to evaluate the importance of the transsulfuration pathway in these cells, particularly in the context of a reserve pathway that channels methionine towards cysteine when the demand for glutathione is high, or under conditions in which the supply of cystine by the x (c) (-) exchanger may be compromised.
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Leonarduzzi G, Sottero B, Poli G. Targeting tissue oxidative damage by means of cell signaling modulators: The antioxidant concept revisited. Pharmacol Ther 2010; 128:336-74. [DOI: 10.1016/j.pharmthera.2010.08.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 08/02/2010] [Indexed: 12/25/2022]
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Kandil S, Brennan L, McBean GJ. Glutathione depletion causes a JNK and p38MAPK-mediated increase in expression of cystathionine-γ-lyase and upregulation of the transsulfuration pathway in C6 glioma cells. Neurochem Int 2010; 56:611-9. [DOI: 10.1016/j.neuint.2010.01.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Accepted: 01/05/2010] [Indexed: 11/27/2022]
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Churchman AT, Anwar AA, Li FYL, Sato H, Ishii T, Mann GE, Siow RCM. Transforming growth factor-beta1 elicits Nrf2-mediated antioxidant responses in aortic smooth muscle cells. J Cell Mol Med 2009; 13:2282-2292. [PMID: 19674192 DOI: 10.1111/j.1582-4934.2009.00874.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The anti-inflammatory properties of transforming growth factor-beta(1) (TGF-beta(1)) account for its protection against atherosclerotic plaque rupture. This study investigates whether activation of the Nrf2 (nuclear factor erythroid 2 [NF-E2]-related factor 2) transcription pathway is involved in TGF-beta(1) mediated induction of the antioxidant enzyme heme oxygenase-1 (HO-1) in smooth muscle cells (SMC). Human aortic smooth muscle cells (HAoSMC) or wild-type and Nrf2-deficient mouse (MAoSMC) aortic SMC were treated with TGF-beta(1) (2.5-10 ng/ml, 0-24 hrs). We report the first evidence that TGF-beta(1) induces Nrf2 mediated HO-1 expression and antioxidant response element activity, which was paralleled by enhanced superoxide production and expression of the NAD(P)H oxidase subunit p22(phox). TGF-beta(1) failed to induce HO-1 expression in MAoSMC derived from Nrf2-deficient mice, and HO-1 induction by TGF-beta(1) in HAoSMC was attenuated by inhibition of extracellular signal regulated kinase or c-jun-N-terminal kinase but not p38 mitogen activated protein kinase. Inhibition of NAD(P)H oxidase or scavenging of superoxide diminished HO-1 induction in response to TGF-beta(1). The oxidative stress agents glucose oxidase (GOx) and diethylmaleate enhanced TGF-beta(1) generation and HO-1 expression in HAoSMC, while antagonism of TGF-beta(1) signalling by adenoviral Smad7 overexpression attenuated their induction of HO-1. Pre-treatment of HAoSMC with TGF-beta(1) reduced nuclear translocation of the pro-apoptotic mediator p53 elicited by GOx. Our findings demonstrate that Nrf2 is a new target of TGF-beta(1) signalling in the vasculature which may contribute to the atheroprotective properties attributed to this growth factor.
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Affiliation(s)
| | - Anila A Anwar
- Cardiovascular Division, School of Medicine, King's College London, UK
| | - Francois Y L Li
- Cardiovascular Division, School of Medicine, King's College London, UK
| | - Hideyo Sato
- Department of Bioresources, Faculty of Agriculture, Yamagata University, Tsuruoka, Japan
| | - Tetsuro Ishii
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tuskuba, Japan
| | - Giovanni E Mann
- Cardiovascular Division, School of Medicine, King's College London, UK
| | - Richard C M Siow
- Cardiovascular Division, School of Medicine, King's College London, UK
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Deruelle F, Baron B. Vitamin C: is supplementation necessary for optimal health? J Altern Complement Med 2009; 14:1291-8. [PMID: 19032072 DOI: 10.1089/acm.2008.0165] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Consumption of vitamin C is essential for life in humans because the body does not synthesize it. Numerous studies have demonstrated that supplementation with vitamin C enhances the immune system, avoids DNA damage, and significantly decreases the risk of a wide range of pathologies, such as cancers, and degenerative and chronic diseases. Moreover, it has been demonstrated that modern crop production, transport, and food storage severely impair the quality of food and provoke a loss in micronutrients, such as vitamin C. OBJECTIVES In this paper, we report that the Recommended Daily Allowance (RDA) in vitamin C is lower than the bodily needs. In fact, it does not seem to ensure true health protection and it appears difficult to reach an effective dose of vitamin C only through food consumption. Furthermore, the literature shows that vitamin C intake higher than the RDA is safe. Therefore, in order to achieve optimal health and avoid a number of diseases, we suggest that, in the present situation, vitamin C supplementation is required. CONCLUSIONS According to the current literature, we would like to emphasize that to ensure an optimal allowance of vitamin C, we advise 1 g daily intake of vitamin C supplementation, accompanied by a diet rich in fruits and vegetables.
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Affiliation(s)
- Fabien Deruelle
- Faculté des Sciences du Sport et de l'Education Physique, Laboratoire d'Etudes de la Motricité Humaine, Université de Lille 2, Ronchin, France.
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Zhu J, Li S, Marshall ZM, Whorton AR. A cystine-cysteine shuttle mediated by xCT facilitates cellular responses toS-nitrosoalbumin. Am J Physiol Cell Physiol 2008; 294:C1012-20. [DOI: 10.1152/ajpcell.00411.2007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We have shown previously that extracellular cysteine is necessary for cellular responses to S-nitrosoalbumin. In this study we have investigated mechanisms involved in accumulation of extracellular cysteine outside vascular smooth muscle cells and characterized the role of cystine-cysteine release in transfer of nitric oxide (NO)-bioactivity. Incubation of cells with cystine led to cystine uptake, reduction, and cysteine release. The process was inhibitable by extracellular glutamate, suggesting a role for system xc−amino acid transporters. Smooth muscle cells express this transporter constitutively and induction of the light chain component (xCT) by either diethyl maleate or 3-morpholino-sydnonimine (SIN-1) led to glutamate-inhibitable cystine uptake and an increased rate of cysteine release from cells. Likewise, overexpression of xCT in smooth muscle cells or endothelial cells led to glutamate-inhibitable cysteine release. The resulting extracellular cysteine was found to be required for transfer of NO from extracellular S-nitrosothiols into cells via system L transporters leading to formation of cellular S-nitrosothiols. Cysteine release coupled to cystine uptake was also found to be required for cellular responses to S-nitrosoalbumin and facilitated S-nitrosoalbumin-mediated inhibition of epidermal growth factor signaling. These data show that xCT expression can constitute a cystine-cysteine shuttle whereby cystine uptake drives cysteine release. Furthermore, we show that extracellular cysteine provided by this shuttle mechanism is necessary for transfer of NO equivalents and cellular responses to S-nitrosoablumin.
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Tosaki T, Sakamoto H, Kitahara J, Imai H, Nakagawa Y. Enhancement of Acetyl-CoA: 1- O-Alkyl-2-lyso- sn-glycero-3-phosphocholine Acetyltransferase Activity by Hydrogen Peroxide. Biol Pharm Bull 2007; 30:272-8. [PMID: 17268064 DOI: 10.1248/bpb.30.272] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The synthesis of platelet-activating factor (PAF) by human umbilical vein endothelial cell (HUVEC) in response to H2O2 was significantly increased in a concentration-dependent manner. When HUVEC were pretreated with diethyl maleate, which depletes intracellular glutathione, PAF synthesis was enhanced 3-fold upon 5 mM H2O2-treatment. Intracellular redox was involved in regulating PAF synthesis, since the addition of antioxidants such as N-acetylcysteine, pyrrolidinecarbodithioic acid (PDTC), and Trolox reduced PAF production in H2O2-treated HUVEC. The activity of acetyl-CoA: 1-O-alkyl-2-lyso-sn-glycero-3-phosphocholine acetyltransferase, which is involved in the last step of PAF synthesis, was also activated in H2O2-treated cells. However, exogenous lyso-PAF addition had not effected to acetyltransferase activity. The acetyltransferase activity responded quickly to H2O2-treatment, but the activation was transitory. A tyrosine kinase inhibitor and a calmodulin antagonist blocked acetyltransferase activity in H2O2-stimulated cells, suggesting that tyrosine kinase and calcium/calmodulin-dependent protein kinase are involved in regulating acetyltransferase activity. These observations suggest that H2O2 is one of the modulators of lyso-PAF acetyltransferase activity via a phosphorylation system and platelet-activating factor (PAF) synthesis.
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Affiliation(s)
- Takaki Tosaki
- School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan
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Kinscherf R, Cafaltzis K, Röder F, Hildebrandt W, Edler L, Deigner HP, Breitkreutz R, Feussner G, Kreuzer J, Werle E, Michel G, Metz J, Dröge W. Cholesterol levels linked to abnormal plasma thiol concentrations and thiol/disulfide redox status in hyperlipidemic subjects. Free Radic Biol Med 2003; 35:1286-92. [PMID: 14607527 DOI: 10.1016/j.freeradbiomed.2003.07.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Treatment of hyperlipidemic patients with the thiol compound N-acetylcysteine (NAC) was previously shown to cause a significant dose-related increase in the high-density lipoprotein (HDL)-cholesterol serum level, suggesting the possibility that its disease-related decrease may result from a diminished thiol concentration and/or thiol/disulfide redox status (REDST) in the plasma. We therefore investigated plasma thiol levels and REDST in normo-/hyperlipidemic subjects with and without coronary heart disease (CHD). The thiol level, REDST, and amino acid concentrations in the plasma and intracellular REDST of peripheral blood mononuclear cells (PBMC) have been determined in 62 normo- and hyperlipidemic subjects. Thirty-three of these subjects underwent coronary angiography, because of clinical symptoms of CHD. All groups of hyperlipidemic patients under test and those normolipidemic individuals with documented coronary stenoses showed a marked decrease in plasma thiol concentrations, plasma and intracellular REDST of PBMCs, and a marked increase in plasma taurine levels. Individual plasma thiol concentrations and plasma REDST were strongly negatively correlated with the serum LDL-cholesterol and positively correlated with the serum HDL-cholesterol level. Together with the earlier report about the effect of NAC on the HDL-cholesterol serum level, our findings suggest strongly that lower HDL-cholesterol serum levels may result from a decrease in plasma thiol level and/or REDST possibly through an excessive cysteine catabolism into taurine.
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Affiliation(s)
- Ralf Kinscherf
- Department of Anatomy and Cell Biology III, Heidelberg University, Heidelberg, Germany.
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