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White CC, Viernes H, Krejsa CM, Botta D, Kavanagh TJ. Fluorescence-based microtiter plate assay for glutamate-cysteine ligase activity. Anal Biochem 2003; 318:175-80. [PMID: 12814619 DOI: 10.1016/s0003-2697(03)00143-x] [Citation(s) in RCA: 225] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Glutamate-cysteine ligase (GCL; also known as gamma-glutamylcysteine synthetase) is the rate-limiting enzyme in glutathione (GSH) synthesis. Traditional assays for the activity of this enzyme are based either on coupled reactions with other enzymes or on high-performance liquid chromatography (HPLC) assessment of gamma-glutamylcysteine (gamma-GC) product formation. We took advantage of the reaction of naphthalene dicarboxaldehyde (NDA) with GSH or gamma-GC to form cyclized products that are highly fluorescent. Hepa-1 cells which were designed to overexpress mouse GCL and mouse liver homogenates were used to evaluate and compare the utility of the NDA method with an assay based on monobromobimane derivatization and HPLC analysis with fluorescence detection. Excellent agreement was found between GCL activities measured by HPLC and NDA-microtiter plate analyses. This assay should be useful for high-throughput GCL activity analyses.
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Hardwick RN, Fisher CD, Canet MJ, Lake AD, Cherrington NJ. Diversity in antioxidant response enzymes in progressive stages of human nonalcoholic fatty liver disease. Drug Metab Dispos 2010; 38:2293-301. [PMID: 20805291 PMCID: PMC2993454 DOI: 10.1124/dmd.110.035006] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Accepted: 08/30/2010] [Indexed: 01/04/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD), which occurs in approximately 17 to 40% of Americans, encompasses progressive stages of liver damage ranging from steatosis to nonalcoholic steatohepatitis (NASH). Inflammation and oxidative stress are known characteristics of NAFLD; however, the precise mechanisms occurring during disease progression remain unclear. The purpose of the current study was to determine whether the expression or function of enzymes involved in the antioxidant response, NAD(P)H:quinone oxidoreductase 1 (NQO1), glutathione transferase (GST), and glutamate cysteine ligase, are altered in the progression of human NAFLD. Human livers staged as normal, steatotic, NASH (fatty), and NASH (not fatty) were obtained from the Liver Tissue Cell Distribution System. NQO1 mRNA, protein, and activity tended to increase with disease progression. mRNA levels of the GST isoforms A1, A2, A4, M3, and P1 increased with NAFLD progression. Likewise, GST A and P protein increased with progression; however, GST M protein levels tended to decrease. Of interest, total GST activity toward the substrate 1-chloro-2,4-dinitrobenzene decreased with NAFLD progression. GSH synthesis does not seem to be significantly dysregulated in NAFLD progression; however, the GSH/oxidized glutathione redox ratio seemed to be reduced with disease severity, indicating the presence of oxidative stress and depletion of GSH throughout progression of NAFLD. Malondialdehyde concentrations were significantly increased with disease progression, further indicating the presence of oxidative stress. Nuclear immunohistochemical staining of nuclear factor E2-related factor 2 (Nrf2), an indicator of activation of the transcription factor, was evident in all stages of NAFLD. The current data suggest that Nrf2 activation occurs in response to disease progression followed by induction of specific Nrf2 targets, whereas functionality of specific antioxidant defense enzymes seems to be impaired as NAFLD progresses.
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Research Support, N.I.H., Extramural |
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Lee JI, Londono M, Hirschberger LL, Stipanuk MH. Regulation of cysteine dioxygenase and γ-glutamylcysteine synthetase is associated with hepatic cysteine level. J Nutr Biochem 2004; 15:112-22. [PMID: 14972351 DOI: 10.1016/j.jnutbio.2003.10.005] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2003] [Revised: 10/03/2003] [Accepted: 10/08/2003] [Indexed: 10/26/2022]
Abstract
Two hepatic enzymes, cysteine dioxygenase (CDO) and gamma-glutamylcysteine synthetase (GCS), play important regulatory roles in the response of cysteine metabolism to changes in dietary sulfur amino acid or protein levels. To examine the time-course of changes in CDO and GCS activities, CDO and GCS-catalytic or heavy subunit protein and mRNA levels, and cysteine and glutathione levels, we adapted rats to either a low protein (LP) or high protein (HP) diet, switched them to the opposite diet, and followed these parameters over 6 days. Hepatic CDO activity and amount, but not mRNA level, increased in response to higher protein intake; the t(1/2) of change for CDO activity or protein level was 22 h for rats switched from a LP to a HP diet and 8 h for rats switched from a HP to a LP diet, suggesting that the HP diet decreased turnover of CDO. Hepatic GCS activity, catalytic subunit amount and mRNA level decreased in response to a higher protein intake. GCS catalytic subunit level changed with a similar t(1/2) for both groups, but the change in GCS activity in rats switched from a LP diet to a HP diet was faster (approximately 16h) than for rats switched from a HP to a LP diet (approximately 74h). Hepatic cysteine and glutathione levels reached new steady states within 12 h (LP to HP) or 24 h (HP to LP). CDO activity appeared to be regulated at the level of protein, probably by diminished turnover of CDO in response to higher protein intake or cysteine level, whereas GCS activity appeared to be regulated both at the level of mRNA and activity state in response to the change in cysteine or protein availability. These findings support a role of cysteine concentration as a mediator of its own metabolism, favoring catabolism when cysteine is high and glutathione synthesis when cysteine is low.
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Wang ST, Chen HW, Sheen LY, Lii CK. Methionine and cysteine affect glutathione level, glutathione-related enzyme activities and the expression of glutathione S-transferase isozymes in rat hepatocytes. J Nutr 1997; 127:2135-41. [PMID: 9372907 DOI: 10.1093/jn/127.11.2135] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Methionine and cysteine are constituents of glutathione. To understand the effects of these two sulfur amino acids on the glutathione (GSH)-dependent detoxification defense system, intracellular GSH and GSH-related enzyme activities, including GSH peroxidase, GSH reductase, GSH S-transferase (GST) and gamma-glutamylcysteine synthetase, were determined. In addition, the expression of three GST isozymes and carbonic anhydrase III (CA III) was examined. Hepatocytes isolated from male Sprague-Dawley rats were cultured with 0.1, 0.3, 0.5 or 1.0 mmol/L each of L-methionine and L-cysteine, for up to 7 d. Cells incubated with 0.5 or 1.0 mmol/L methionine and cysteine had increased intracellular GSH. A twofold increase was observed on d 6 compared with freshly isolated hepatocytes (P < 0.05). However, intracellular GSH was lower in cells treated with 0.3 or 0.1 mmol/L each of methionine and cysteine than in cells tested with 0.5 or 1.0 mmol/L. Although the GSH level differed significantly between cells cultured with 0.3 or 1.0 mmol/L of methionine and cysteine, GSH-related enzymes did not differ at these two concentrations. The activity generally remained constant for the first 24 h, then increased up to d 4. Immunodetection analysis revealed no difference in the level of CA III and GST isoforms, Ya, Yb and Yp, with amino acids each at a concentration of at least 0.3 mmol/L. Yp expression steadily increased up to d 7. Most proteins decreased rapidly after 48 h when cultured with 0.1 mmol/L of methionine and cysteine; however, the Yp level increased up to d 6. In conclusion, results indicate that a twofold increase of intracellular GSH is reached by adding methionine and cysteine at a concentration >0.5 mmol/L to the culture medium. The concentrations of methionine and cysteine for maintaining hepatic GSH are higher than for GSH-related enzyme activity and for GST isoform expression.
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O'Dwyer PJ, Szarka CE, Yao KS, Halbherr TC, Pfeiffer GR, Green F, Gallo JM, Brennan J, Frucht H, Goosenberg EB, Hamilton TC, Litwin S, Balshem AM, Engstrom PF, Clapper ML. Modulation of gene expression in subjects at risk for colorectal cancer by the chemopreventive dithiolethione oltipraz. J Clin Invest 1996; 98:1210-7. [PMID: 8787684 PMCID: PMC507543 DOI: 10.1172/jci118904] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Prolonged exposure to mutagenic substances is strongly associated with an individual's risk of developing colorectal cancer. Clinical investigation of oltipraz as a chemopreventive agent is supported by its induction of the expression of detoxication enzymes in various tissues, and its protective activity against the formation of chemically induced colorectal tumors in animals. The goals of the present study were: to determine if oltipraz could induce detoxicating gene expression in human tissues; to identify effective non-toxic doses for more extensive clinical testing; and to establish a relationship between effects in the colon mucosa and those in a more readily available tissue, the peripheral mononuclear cell. 24 evaluable patients at high risk for colorectal cancer were treated in a dose-finding study with oltipraz 125, 250, 500, or 1,000 mg/m2 as a single oral dose. Biochemical analysis of sequential blood samples and colon mucosal biopsies revealed increases in glutathione transferase activity at the lower dose levels. These effects were not observed at the higher doses. More pronounced changes were observed in detoxicating enzyme gene expression in both tissues at all doses. Peripheral mononuclear cell and colon mRNA content for gamma-glutamylcysteine synthetase (gamma-GCS) and DT-diaphorase increased after dosing to reach a peak on day 2-4 after treatment, and declined to baseline in the subsequent 7-10 d. The extent of induction of gene expression in colon mucosa reached a peak of 5.75-fold for gamma-GCS, and a peak of 4.14-fold for DT-diaphorase at 250 mg/m2 ; higher doses were not more effective. Levels of gamma-GCS and DT-diaphorase correlated closely (P < or = 0.001) between peripheral mononuclear cells and colon mucosa both at baseline and at peak. These findings demonstrate that the administration of minimally toxic agents at low doses may modulate the expression of detoxicating genes in the tissues of individuals at high risk for cancer. Furthermore, peripheral mononuclear cells may be used as a noninvasive surrogate endpoint biomarker for the transcriptional response of normal colon mucosa to drug administration.
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Harju T, Kaarteenaho-Wiik R, Soini Y, Sormunen R, Kinnula VL. Diminished immunoreactivity of gamma-glutamylcysteine synthetase in the airways of smokers' lung. Am J Respir Crit Care Med 2002; 166:754-9. [PMID: 12204877 DOI: 10.1164/rccm.2112014] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Glutathione (GSH) plays a major role in protecting the airways against oxidative stress. The rate-limiting enzyme in de novo GSH synthesis is gamma-glutamylcysteine synthetase (gamma-GCS), which is induced by acute exposure to GSH-depleting cytokines and oxidants, but downregulated by transforming growth factor beta and prolonged oxidant exposure, at least in vitro. Cell-specific expression or regulation of gamma-GCS may play an important role both in the defense against oxidants and in the pathogenesis of oxidant-associated airway diseases. In this study, the localizations of gamma-GCS heavy (gamma-GCS-HS) and light (gamma-GCS-LS) subunits were investigated by immunohistochemistry in 22 patients with chronic obstructive pulmonary disease (COPD), 20 smokers without COPD, and 13 lifelong nonsmokers. The ultrastructural distributions of both gamma-GCS subunits were assessed by immuno-electron microscopy. Both subunits were expressed most prominently in the large airways, and their ultrastructural localization was both cytoplasmic and along the plasma membrane. The expression of gamma-GCS-HS was stronger in the central bronchial epithelium than in the peripheral bronchioli (p = 0.020), or in alveolar macrophages (p = 0.008). The expression of gamma-GCS-HS in the central bronchial epithelium showed a tendency to be higher in nonsmokers compared with all smokers (p = 0.052). Alveolar macrophages of nonsmokers had higher levels of gamma-GCS-HS (p = 0.001) and gamma-GCS-LS (p = 0.001) than did smokers. The expression of gamma-GCS-HS in the central bronchial epithelium was more marked in nonsmokers than in patients with COPD (p = 0.015), the difference between smokers and patients with COPD was not significant. In conclusion, the heavy and light subunits of gamma-GCS are mainly expressed in the large airways. Their tendency to decrease in cigarette smokers may further predispose lung cells to ongoing oxidant stress, which contributes to the progression of lung injury.
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Comparative Study |
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Bergamo P, Maurano F, Rossi M. Phase 2 enzyme induction by conjugated linoleic acid improves lupus-associated oxidative stress. Free Radic Biol Med 2007; 43:71-9. [PMID: 17561095 DOI: 10.1016/j.freeradbiomed.2007.03.023] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2006] [Revised: 03/14/2007] [Accepted: 03/27/2007] [Indexed: 10/23/2022]
Abstract
Conjugated linoleic acid (CLA) exhibits anticancer and anti-inflammatory properties. Its ability to increase total GSH (GSH+GSSG) amount and gamma-glutamylcysteine ligase (gammaGCL) protein expression was recently associated with the inhibition of typical pathological signs in MRL/MpJ-Fas(lpr) mice (MRL/lpr). In the present study the ability of CLA to modulate oxidative stress and phase 2 enzyme activity in the same animal model was investigated. Disease severity was associated with age-dependent production of anti-double-stranded DNA antibodies (anti-dsDNA IgGs) and with enhanced extent of oxidative stress markers: reduced total GSH, increased protein 3-nitrotyrosines (3-NT), and protein-bound carbonyl (PC) amounts. To examine the effect of CLA on antioxidant status, CLA or olive oil (as control) was administered to pregnant MRL/lpr mice. Significantly higher total GSH and Trolox equivalent antioxidant capacity (TEAC) levels were measured in serum of CLA-treated dams (and their pups), as compared with controls. Finally, the antioxidant and chemopreventive properties of CLA were investigated in old MRL/lpr mice. Sera of CLA-treated mice contained higher concentrations of total GSH which were negatively correlated with the levels of oxidative stress markers. Moreover, increased GSH, gammaGCL, glutathione S-transferase (GSTs), and NAD(P)H:quinone oxidoreductase (NQO1) activities were measured in liver and spleen of CLA-treated animals. In conclusion our data indicate that the activation of detoxifying enzymes may be one of the mechanisms whereby dietary CLA down-regulates oxidative stress in MRL/lpr mice.
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Watanabe K, Yamano Y, Murata K, Kimura A. The nucleotide sequence of the gene for gamma-glutamylcysteine synthetase of Escherichia coli. Nucleic Acids Res 1986; 14:4393-400. [PMID: 2872655 PMCID: PMC311453 DOI: 10.1093/nar/14.11.4393] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The nucleotide sequence of the gsh I gene for gamma-glutamylcysteine synthetase(GSH I) of Escherichia coli B has been determined. The gsh I structural gene contains 1557 bases in length and predicted a ploypeptide of 518 amino acids with a calculated molecular weight of 58,251. The value is in good agreement with that obtained from gel filtration and SDS/PAGE of GSH I. The initiation codon 5 bp downstream of putative Shine-Dalgarno sequence was an unusual TTG, which encoded methionine. For transcription, two sets of consensus promoter signals(-10 and -35 regions) overlapping each other were identified. The terminator signal shows the favored stem-loop structure with an adequate free energy delta G = -22.80 kcal/mol.
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Fukino H, Hirai M, Hsueh YM, Moriyasu S, Yamane Y. Mechanism of protection by zinc against mercuric chloride toxicity in rats: effects of zinc and mercury on glutathionine metabolism. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH 1986; 19:75-89. [PMID: 2875192 DOI: 10.1080/15287398609530908] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
To investigate the mechanism by which zinc suppresses mercury toxicity, the effects of zinc and mercury on glutathione (GSH) metabolism in the rat kidney were studied. When the time course of GSH level in the rat kidney was examined at 2, 6, and 12 h after treatment of rats with both metals, an increase of GSH was found and was apparently related to the activation of some GSH-associated enzymes. In the kidney of rats treated with both metals, the response of the protective function involving GSH and GSH-associated enzymes depended on the magnitude of mercury toxicity but appeared to be independent of the zinc dosage. The administration of diethyl maleate (DEM), which depletes GSH, increased lipid peroxidation and mercury toxicity concomitantly with a decrease of GSH level in the kidney of rats treated with zinc and mercury. In conclusion, the data suggest that an increased GSH level in the kidney resulting from the activation of GSH-associated enzymes plays a role in the protective effect of zinc against mercury toxicity.
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Sethna SS, Holleschau AM, Rathbun WB. Activity of glutathione synthesis enzymes in human lens related to age. Curr Eye Res 1982; 2:735-42. [PMID: 6138216 DOI: 10.3109/02713688209020005] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The high levels of both enzymes of glutathione synthesis found in the infant human lens rapidly reached lower levels by age 10, and thereafter the rate of decrease diminished. Glutathione synthetase activity in the 6 month old lens was six-fold (units/g lens), four-fold (units/mg soluble protein) and two-fold (units/lens) higher than that in the 83 year old, clear human lens. gamma-Glutamylcysteine synthetase activity in the 6 month old lens was sixteen-fold (units/g lens), ten-fold (units/mg soluble protein) and six-fold (units/lens) higher than that in the 83 year old, clear human lens. When lenses from the young adult beagle, rabbit, bovine, and humans are compared, glutathione synthetase activity (units/g lens) varies by about two-fold. gamma-Glutamylcysteine synthetase activity (units/g lens) is quite similar in the first three species, whereas the enzyme activity is more than a magnitude less in young adult human lenses, and becomes much less with increasing age and in a high proportion of life-support system organ donors. The enzyme activity was undetectable in a few of the latter lenses. Loss of activity was not due to increased susceptibility to heat denaturation. The low levels of the enzyme, and total loss in some situations, suggest that gamma-glutamylcysteine synthetase may be an Achilles' Heel of human lens metabolism.
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Comparative Study |
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Langley-Evans SC, Phillips GJ, Jackson AA. Fetal exposure to low protein maternal diet alters the susceptibility of young adult rats to sulfur dioxide-induced lung injury. J Nutr 1997; 127:202-9. [PMID: 9039819 DOI: 10.1093/jn/127.2.202] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The maternal diet is an important determinant of glutathione-related metabolism in rats. Glutathione (GSH) may play a major role in the detoxification of sulfur dioxide (SO2) within the lungs. The effects of fetal exposure to a low protein maternal diet upon later susceptibility to pulmonary injury induced by chronic SO2 exposure were evaluated in young adult rats. Pregnant rats were fed purified diets containing 180 g casein/kg (control diet) or 120, 90 or 60 g casein/kg (experimental diets). After parturition, all dams were fed a standard non-purified diet (189 g protein/kg diet). The pups thus differed only in terms of protein nutrition during gestation. At seven wk of age the male pups were housed in either room air or 286 microg SO2/m3 for 5 h/d during a 28-d period. At the end of the final SO2 treatment period, the rats exposed to 90 or 60 g casein/kg diets in utero exhibited significantly greater pulmonary injury, as assessed by bronchoalveolar lavage, than did those exposed to control diet in utero. Significant maternal diet-induced differences in activities of enzymes of the gamma-glutamyl cycle were noted in the lungs and livers of rats which had not undergone SO2 treatment. Furthermore, the response of these enzyme activities to SO2 treatment was determined by prior exposure to the maternal diet. SO2-treated rats exposed to control diet (180 g casein/kg) and low protein diet (60 g casein/kg), but not those exposed to 120 or 90 g casein/kg diets, tended to augment the activities, relative to rats not treated with SO2, of enzymes which maintain tissue GSH status either through synthesis or recycling. Differences in susceptibility to SO2-induced tissue injury may be related to programming of GSH metabolism by the maternal diet. Alternatively, impaired immune and acute phase responses to an inflammatory insult may account for a failure to resolve initial SO2-induced injury in rats exposed to low protein maternal diets.
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Mayer RD, Lee KE, Cockett AT. Inhibition of cisplatin-induced nephrotoxicity in rats by buthionine sulfoximine, a glutathione synthesis inhibitor. Cancer Chemother Pharmacol 1987; 20:207-10. [PMID: 2890443 DOI: 10.1007/bf00570486] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
DL-Buthionine-(S,R)-sulfoximine (BSO), a glutathione-depleting agent, was found to diminish the nephrotoxic effect of cisplatin (cis-diamminedichloroplatinum). Pretreatment of rats with BSO (4 mmol/kg s.c.) 2 h prior to cisplatin, either as a single dose of 5 mg/kg or at a daily dose of 2.5 mg/kg for 3 consecutive days, resulted in diminished elevations of plasma BUN concentration and decreased cisplatin-induced inhibition of renal gamma-glutamylcysteine synthetase and gamma-glutamyl transpeptidase activity measured 6 days following treatment. Administration of BSO prior to cisplatin at 7.5 mg/kg did not significantly alter the effect of cisplatin on either BUN concentration or enzyme activity. The influence of BSO pretreatment on the antitumor activity of cisplatin was studied using implantation of a murine bladder cancer (MBT-2) in C3H mice. Pretreatment of mice with BSO (5 mmol/kg) did not influence cisplatin antitumor efficacy.
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Comparative Study |
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Gegg ME, Clark JB, Heales SJR. Determination of glutamate-cysteine ligase (gamma-glutamylcysteine synthetase) activity by high-performance liquid chromatography and electrochemical detection. Anal Biochem 2002; 304:26-32. [PMID: 11969185 DOI: 10.1006/abio.2001.5607] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The tripeptide glutathione (gamma-glutamylcysteinylglycine; GSH) is the predominant low molecular mass thiol in cells. The function of GSH is of considerable interest, with the molecule being implicated in numerous cellular processes in addition to being a major cellular antioxidant. The enzyme glutamate-cysteine ligase (GCL) is the rate-limiting step in GSH synthesis. The GCL assay described here is based on high-performance liquid chromatography and exploits the electrochemically active nature of gamma-glutamylcysteine (gamma-GC), the product of GCL activity. This method allows for the direct detection of gamma-GC rather than relying on derivatization of the molecule or linked assays. The sensitivity of the assay is sufficient to allow for the measurement of GCL activity in cultured cells. The specific activity of GCL in rat primary culture astrocytes was 9.7 +/- 1.7 nmol gamma-GC synthesized/min/mg protein.
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Forman HJ, Shi MM, Iwamoto T, Liu RM, Robison TW. Measurement of gamma-glutamyl transpeptidase and gamma-glutamylcysteine synthetase activities in cells. Methods Enzymol 1995; 252:66-71. [PMID: 7476375 DOI: 10.1016/0076-6879(95)52009-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Comparative Study |
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Agardh CD, Gustavsson C, Hagert P, Nilsson M, Agardh E. Expression of antioxidant enzymes in rat retinal ischemia followed by reperfusion. Metabolism 2006; 55:892-8. [PMID: 16784960 DOI: 10.1016/j.metabol.2006.02.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2005] [Accepted: 02/01/2006] [Indexed: 01/26/2023]
Abstract
To evaluate the expression and protein levels of antioxidant enzymes in the rat retina exposed to oxidative stress induced by ischemia-reperfusion injury. Retinal ischemia was induced in female Wistar rats by ligation of the optic nerve and vessels behind the left eye bulb, and was followed by reperfusion for 0, 3, 6, or 24 hours. The right eye served as control. RNA and protein were extracted simultaneously from each retina. Expressions of the endogenous antioxidant enzymes glutathione peroxidase (GPx1), catalase (CAT), copper/zinc superoxide dismutase, manganese superoxide dismutase, and the catalytic subunit of glutamylcysteine ligase (GCLc) were analyzed with real-time reverse transcription polymerase chain reaction and related to the endogenous control cyclophilin B. Protein levels were measured with Western blot analysis. During the early phase (0 or 3 hours) of reperfusion, no changes were seen in enzyme expression. After 6 hours, GCLc expression increased by a factor of 1.14 (P = .034), followed by a decline of 0.80 after 24 hours (P = .00004), according to the comparative Ct method. After 24 hours of reperfusion, GPx1 expression increased by a factor of 1.14 (P = .028), and CAT had decreased by 0.82 (P = .022). Expressions of copper/zinc superoxide dismutase and manganese superoxide dismutase showed a tendency toward a decrease by factors of 0.86 (P = .055) and 0.88 (P = .053), respectively, after 24 hours. Protein levels did not differ for any of the antioxidants, regardless of reperfusion time. The slightly increased messenger RNA expression of GPx1 after 24 hours of reperfusion with a concomitant very modest decrease in CAT and GCLc expression and no change in protein levels indicate a very modest, if any, response to oxidative stress generated by ischemia followed by reperfusion in rat retina.
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Agardh E, Gustavsson C, Hagert P, Nilsson M, Agardh CD. Modifying a standard method allows simultaneous extraction of RNA and protein, enabling detection of enzymes in the rat retina with low expressions and protein levels. Metabolism 2006; 55:168-74. [PMID: 16423622 DOI: 10.1016/j.metabol.2005.08.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2005] [Accepted: 08/22/2005] [Indexed: 10/25/2022]
Abstract
The aim of the study was to evaluate messenger RNA and protein expression in limited amounts of tissue with low protein content. The Chomczynski method was used for simultaneous extraction of RNA, and protein was modified in the protein isolation step. Template mass and cycling time for the complementary DNA synthesis step of real-time reverse transcription-polymerase chain reaction (RT-PCR) for analysis of catalase, copper/zinc superoxide dismutase, manganese superoxide dismutase, the catalytic subunit of glutamylcysteine ligase, glutathione peroxidase 1, and the endogenous control cyclophilin B (CypB) were optimized before PCR. Polymerase chain reaction accuracy and efficacy were demonstrated by calculating the regression (R2) values of the separate amplification curves. Appropriate antibodies, blocking buffers, and running conditions were established for Western blot, and protein detection and multiplex assays with CypB were performed for each target. During the extraction procedure, the protein phase was dissolved in a modified washing buffer containing 0.1% sodium dodecyl sulfate, followed by ultrafiltration. Enzyme expression on real-time RT-PCR was accomplished with high reliability and reproducibility (R2, 0.990-0.999), and all enzymes except for glutathione peroxidase 1 were detectable in individual retinas on Western blot. Western blot multiplexing with CypB was possible for all targets. In conclusion, connecting gene expression directly to protein levels in the individual rat retina was possible by simultaneous extraction of RNA and protein. Real-time RT-PCR and Western blot allowed accurate detection of retinal protein expressions and levels.
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Bouter S, Kerklaan PR, Zoetemelk CE, Mohn GR. Biochemical characterization of glutathione-deficient mutants of Escherichia coli K12 and Salmonella strains TA1535 and TA100. Biochem Pharmacol 1988; 37:577-81. [PMID: 2893622 DOI: 10.1016/0006-2952(88)90128-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Glutathione-deficient mutants of Escherichia coli K12/343/408 and Salmonella typhimurium TA1535 and TA100 were characterized biochemically by measuring the rate of formation of (14C)gamma-glutamylcysteine and (14C)glutathione in cell-free extracts of the strains. gamma-Glutamylcysteine synthetase activity was found to be absent in the NGR-2 mutant of E. coli and in the Salmonella mutants TA1535/NG-19, TA100/NG-57 and TA100/NG-11, while only low activities were found in the NGR-9 and NG-54 mutant of E. coli and Salmonella respectively. These results correspond with the decreased levels of glutathione found in these strains. Extracts of the parent strains have normal glutathione levels and show high gamma-glutamylcysteine synthetase activities. It is concluded that the present GSH-deficient strains of E. coli and Salmonella are gshA mutants, analogous to those previously described in E. coli. In addition, the present results show that the fluorometric method used for the determination of glutathione, employing o-phthalaldehyde as a reagent, is not specific for glutathione (at pH 8.0), but also sensitively reacts with gamma-glutamylcysteine.
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Díaz-Jaramillo M, Ferreira JL, Amado LL, Ventura-Lima J, Martins A, Retamal MR, Urrutia R, Bertrán C, Barra R, Monserrat JM. Biomonitoring of antioxidant and oxidative stress responses in Perinereis gualpensis (Polychaeta: Nereididae) in Chilean estuarine regions under different anthropogenic pressure. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2010; 73:515-523. [PMID: 20083306 DOI: 10.1016/j.ecoenv.2009.12.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2008] [Revised: 11/28/2009] [Accepted: 12/03/2009] [Indexed: 05/28/2023]
Abstract
This study aimed to analyze oxidative stress parameters, including levels of the antioxidant glutathione (GSH), activity of glutamate-cysteine ligase (GCL) and glutathione-S-transferase (GST), total antioxidant capacity and protein oxidation, in the polychaete Perinereis gualpensis (Nereididae) collected from the Biobío, Itata, Valdivia and Lingue estuaries in Chile, which present different degrees of anthropogenic pressure. Sampling sites were characterized considering a geographic information system and the physicochemical characteristics of water and sediment. Significant differences (p<0.05) were observed between the sampling sites for most of the responses (GSH, GCL, GST and antioxidant capacity), mainly related to human activities such as agriculture, industry, among others. Multivariate correlation analysis indicates a certain relationship of antioxidant responses with human activities, salinity, and worm weight, this last employed to standardize GST and antioxidant capacity. These results clearly indicate biomarker responses in P. gualpensis in Biobío and Valdivia estuaries, the more affected by human activities.
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Kavanagh TJ, Raghu G, White CC, Martin GM, Rabinovitch PS, Eaton DL. Enhancement of glutathione content in glutathione synthetase-deficient fibroblasts from a patient with 5-oxoprolinuria via metabolic cooperation with normal fibroblasts. Exp Cell Res 1994; 212:69-76. [PMID: 7909755 DOI: 10.1006/excr.1994.1119] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Fibroblasts from patients with the disease 5-oxoprolinuria have reduced glutathione synthetase activity and are thus glutathione (GSH) deficient. In this study, 5-oxoprolinuria fibroblasts (GM3877 cells) contained less GSH than normal diploid fibroblasts as determined by biochemical analysis and by flow cytometry using monochlorobimane. They also contained lower gamma-glutamylcysteine synthetase activity than normal cells. However, cocultures of GM3877 cells and normal cells displayed either normal or slightly elevated GSH content, depending upon the assay used. When differentially labeled with fluorescent beads, cocultured, and then isolated by fluorescence-activated cell sorting, both GM3877 cells and normal cells had GSH content similar to that of sorted normal cells cultured alone, whereas sorted GM3877 cells cultured alone showed depressed GSH content. GM3877 cells had detectable levels of gamma-glutamylcysteine (gamma-GC) when cultured alone, but gamma-GC was undetectable in these cells when they were cocultured with normal cells, indicating that it was efficiently metabolized to GSH by the normal cells. These changes in low-molecular-weight thiols were likely to have been mediated by metabolic cooperation across gap junctions because they were dependent upon confluency and because media conditioned by either cell type failed to significantly alter the GSH content of the other cell type. Cocultures exposed to moderate levels of hydrogen peroxide showed less depletion of GSH than GM3877 cells cultured alone, suggesting that the sharing of low-molecular-weight thiols or other reductants via metabolic cooperation can protect cells from oxidative stress.
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Yantiri F, Gasparyan A, Andersen JK. Glutamyl cysteine synthetase catalytic and regulatory subunits localize to dopaminergic nigral neurons as well as to astrocytes. J Neurosci Res 2001; 64:203-6. [PMID: 11288148 DOI: 10.1002/jnr.1066] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Glutathione (GSH) is considered one of the primary antioxidant compounds in the brain, important for the removal of peroxides from this organ. GSH levels have been reported to be significantly lower in the substantia nigra (SN) of Parkinson patients vs. age-matched controls. Curiously, GSH has been proposed to be present in brain astrocytes rather than in neurons even though these cells are not lost in Parkinson disease. We report that the catalytic and regulatory subunit proteins of glutamyl cysteine synthetase (GCS), the primary enzyme involved in GSH synthesis, are present not only in astrocytes but also in dopaminergic neurons of the SN. This may have important implications in terms of GSH loss associated with Parkinson disease.
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Soini Y, Kallio JP, Hirvikoski P, Helin H, Kellokumpu-Lehtinen P, Tammela TLJ, Peltoniemi M, Martikainen PM, Kinnula LV. Antioxidant enzymes in renal cell carcinoma. Histol Histopathol 2006; 21:157-65. [PMID: 16329040 DOI: 10.14670/hh-21.157] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The aim of the study was to estimate the significance of oxidative/nitrosative damage and expression of antioxidant enzymes in renal cell carcinomas (RCC). For this we investigated immunohistochemically six antioxidant enzymes (AOEs) including MnSOD, ECSOD, thioredoxin, thioredoxin reductase, and gammaglutamyl cysteine synthetase heavy and light chain in 138 RCCs. As an indicator of oxidative/nitrosative damage, sections were stained with an antibody to nitrotyrosine. The extent of apoptosis was evaluated by TUNEL method and proliferation by immunohistochemistry to Ki67. Variable expression of all AOEs could be seen in RCC with expression of MnSOD being strongest. Nitrotyrosine was significantly associated with high grade tumors. MnSOD was associated with tumors of a lower stage. Cases showing ECSOD reactivity had higher and cases expressing thioredoxin lower apoptotic index than other tumors. No association with patient prognosis was observed. According to the results renal cell carcinomas show oxidative/nitrosative damage which, according to nitrotyrosine staining, was higher in high grade tumors. Of AOEs, MnSOD was more abundantly expressed in low stage tumors suggesting that its antioxidant function could play a main role to prevent development of oxidative damage leading to more aggressive tumors.
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Mathivadhani P, Shanthi P, Sachdanandam P. Effect ofSemecarpus anacardiumLinn. Nut Milk Extract on Glutathione and Its Associated Enzymes in Experimentally Induced Mammary Carcinoma. J Med Food 2006; 9:265-9. [PMID: 16822214 DOI: 10.1089/jmf.2006.9.265] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Reduced glutathione (GSH) is a ubiquitous thiol-containing tripeptide that plays a key role in the etiology of many diseases and, in particular, cancer. GSH, the foremost internal protective system, participates directly in the destruction of free radical compounds and detoxification of carcinogens. The effect of Semecarpus anacardium nut milk extract was studied for gaining insight into the disease relationship to GSH and its metabolizing enzymes. Mammary carcinoma was induced by giving 7,12-dimethylbenz[a]anthracene (DMBA) (25 mg/mL of olive oil) perorally by gastric intubation, and nut milk extract of S. anacardium was administered orally (200 mg/kg of body weight/day) for 14 days to mammary carcinoma-bearing rats. The levels of GSH and its metabolizing enzyme activities were determined in liver and kidney homogenates. Significant decreases in GSH, glutathione peroxidase, glutathione S-transferase, glutathione reductase, and gamma-glutamylcysteine synthetase and a concomitant increase in oxidized glutathione, gamma-glutamyl transpeptidase, and glucose 6-phosphate dehydrogenase were observed in DMBA-induced mammary carcinoma in rats, while drug treatment reversed the conditions to near normal levels. There was a marked increase in GSH level and gamma-glutamylcysteine synthetase activity in drug control rats. These findings suggest that S. anacardium can exert its protective effect in maintaining the glutathione redox status by restoring the associated enzymes against oxidative stress in experimental mammary carcinoma.
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Yan N, Meister A. Amino acid sequence of rat kidney gamma-glutamylcysteine synthetase. J Biol Chem 1990; 265:1588-93. [PMID: 1967255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
gamma-Glutamylcysteine synthetase catalyzes the first step in the synthesis of glutathione. The enzyme isolated from rat kidney has two subunits (heavy, Mr 73,000; and light, Mr 27,700) which may be dissociated by treatment with dithiothreitol. The heavy subunit exhibits all of the catalytic activity of the isolated enzyme and also feedback inhibition by glutathione. The light subunit has no known function and may not be an integral part of the enzyme. cDNA clones encoding rat kidney gamma-glutamylcysteine synthetase were isolated from a lambda gt11 cDNA library by immunoscreening with antibody against the isolated enzyme and further screening with oligonucleotide probes derived from several peptides whose sequences were determined by the Edman method. The nucleotide sequence of the mRNA for the heavy subunit was deduced from the sequences of the cDNA of three such clones. The sequence, which codes for 637 residues (Mr 72,614), contains all four of the independently determined peptide sequences (approximately 100 residues). This amino acid sequence shows extremely low overall similarity to that of gamma-glutamylcysteine synthetase isolated from Escherichia coli.
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Comparative Study |
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Gomi A, Shinoda S, Masuzawa T, Ishikawa T, Kuo MT. Transient induction of the MRP/GS-X pump and gamma-glutamylcysteine synthetase by 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3- nitrosourea in human glioma cells. Cancer Res 1997; 57:5292-9. [PMID: 9393752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Treatment of human glioma A172 cells with 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea (ACNU), an alkylating antitumor agent the primary target of which has been thought to be DNA, resulted in elevated expression of mRNA for multidrug resistance-associated protein (MRP) within the first 2 h and then a decrease in expression 24 h after the treatment. Western blot analyses revealed that levels of MRP in these ACNU-treated cells paralleled mRNA levels. Membrane vesicles prepared from ACNU-treated cells also displayed elevated transport activities for leukotriene C4, a known substrate for MRP. Gamma-glutamylcysteine synthetase (gamma-GCS) mRNA expression was coinduced with MRP by ACNU. Because gamma-GCS is the rate-limiting enzyme involved in the de novo biosynthesis of glutathione, increases in glutathione were also transiently induced by ACNU. These results demonstrate for the first time that the expression of functional MRP and gamma-GCS can be transiently coinduced by ACNU. Multiple short exposures (1 h) of ACNU following a long duration (1 week) of drug-free conditions resulted in the development of an ACNU-resistant population (designated A172R) that overexpressed MRP/gamma-GCS mRNA and had elevated transport activities for leukotriene C4. A172R exhibited cross-resistance to the antitumor drug doxorubicin and heavy metal sodium arsenate but not to cisplatin. Our results also demonstrate that intermittent treatments of human glioma cells with ACNU can lead to the development of MRP-related multidrug resistance. These results, taken together, reveal a possible new mechanism of the development of drug resistance for the antitumor nitrosoureas.
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Dennda G, Kula MR. Assay of the glutathione-synthesizing enzymes by high-performance liquid chromatography. Biotechnol Appl Biochem 1986; 8:459-64. [PMID: 2876717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We report a new convenient assay of the activity of gamma-glutamylcysteine synthetase (EC 6.3.2.2) and glutathione synthetase (EC 6.3.2.3) in crude microbial extracts as well as in purified enzyme preparations. The assay is based on the quantitative analysis of the reaction products by high-performance liquid chromatography after derivatization of the thiol group with 5,5'-dithiobis-(2-nitrobenzoic acid) as described by J. Reeve, J. Kuhlenkamp, and N. Kaplowitz [(1980) J. Chromatogr. 194, 424-428]. In addition, the procedure yields information on basal levels of gamma-glutamylcysteine and glutathione in crude microbial extracts. The two enzymes responsible for glutathione biosynthesis can be determined in parallel under the same chromatographic conditions. No prior separation from substrates and by-products is necessary. Product formation is linear with time for at least 30 min between 0.03 and 12 mU for both enzymes. Even in crude extracts 0.2-0.5 nmol of products formed can be detected with certainty. The method was found to be sensitive and highly reproducible.
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