The Experts below are selected from a list of 267 Experts worldwide ranked by ideXlab platform
Henry Jay Forman - One of the best experts on this subject based on the ideXlab platform.
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increased Gamma Glutamylcysteine synthetase and Gamma glutamyl transpeptidase activities enhance resistance of rat lung epithelial l2 cells to quinone toxicity
American Journal of Respiratory Cell and Molecular Biology, 1996Co-Authors: Hepeng Hu, Timothy W Robison, Henry Jay FormanAbstract:Tert-butylhydroquinone (TBHQ) is a monofunctional Phase II enzyme inducer, which produces reactive oxygen species. Incubation with a sublethal concentration of TBHQ increased the activities of both Gamma-glutamyl transpeptidase (GGT) and Gamma-Glutamylcysteine synthetase (GCS), although the mechanisms are different (Liu and colleagues, accompanying manuscript). In this study, we found that TBHQ increased intracellular glutathione (GSH) content in rat lung epithelial L2 cells. L2 cells pretreated with a nontoxic concentration of TBHQ (50 microM) acquired resistance to a subsequent challenge with a normally lethal concentration of TBHQ (200 microM). Pretreatment with L-buthionine S,R-sulfoximine (BSO), an inhibitor of GCS, prevented the TBHQ-induced increase in GSH and markedly diminished resistance to 200 microM TBHQ. Similarly, pretreatment with acivicin, an inhibitor of GGT, also prevented the TBHQ-induced increase in GSH and markedly diminished resistance to 200 microM TBHQ. Nevertheless, blockage of GG...
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differential enhancement of Gamma glutamyl transpeptidase and Gamma Glutamylcysteine synthetase by tert butylhydroquinone in rat lung epithelial l2 cells
American Journal of Respiratory Cell and Molecular Biology, 1996Co-Authors: Hepeng Hu, Timothy W Robison, Henry Jay FormanAbstract:Sublethal quinone-mediated oxidative stress stimulates increases in the activities and mRNA levels of Gamma-glutamyl transpeptidase (GGT) and Gamma-Glutamylcysteine synthetase (GCS) in rat lung epithelial L2 cells [Kugelman, A. et al. 1994. Am. J. Respir. Cell Mol. Biol. 11:586-592; Shi, M. M. et al. 1994. J. Biol. Chem. 269:26512-26517]. The present study demonstrated that the quinone-induced increases in these two enzymes were differentially regulated. L2 cells were exposed to various concentrations of tertiary-butylhydroquinone (TBHQ) for different periods of times. TBHQ increased the activities and the mRNAs for GGT and the catalytic subunit of GCS; however, the time- and concentration-dependencies differed. With 50 microM TBHQ, GCS activity increased significantly by 6 h whereas the activity of GGT was not increased until later. Under the same conditions, the highest GCS-mRNA level observed was at 6 h whereas the mRNA level of GGT increased after 6 h, reached a higher level at 12 h, and then returned...
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quinone induced oxidative stress elevates glutathione and induces Gamma Glutamylcysteine synthetase activity in rat lung epithelial l2 cells
Journal of Biological Chemistry, 1994Co-Authors: Amir Kugelman, Takeo Iwamoto, L Tian, Henry Jay FormanAbstract:Abstract Glutathione (GSH) is one of the most important physiological antioxidants involved in detoxification of hydrogen peroxide and lipid hydroperoxide. Previous studies have shown that cells can maintain and even increase cellular GSH content in response to sublethal oxidative stress. We hypothesized that Gamma-Glutamylcysteine synthetase (Gamma GCS), the rate-limiting enzyme in de novo GSH synthesis, could be induced by oxidative stress. Rat lung epithelial L2 cells were challenged with 2,3-dimethoxy-1,4-naphthoquinone (DMNQ), generates O2.- and H2O2 continuously through redox cycling. Exposure of confluent L2 cells with sublethal doses of DMNQ caused sustained elevation of cellular GSH levels over a 24-h period (to 2.5-fold with 10 microM). DMNQ caused increases in Gamma GCS activity (70% at 24 h with 10 microM), the Gamma GCS catalytic heavy subunit (Gamma GCS-HS) protein level, and Gamma GCS-HS mRNA content (approximately 4-fold after 6 h with 10 microM). The elevation of Gamma GCS-HS mRNA by DMNQ was eliminated by co-incubation with actinomycin D. Nuclear run-on experiments demonstrated that the transcriptional rate of the Gamma GCS-HS gene was increased by 3- or 6-h exposure to 10 microM DMNQ. Our results suggested that the induction of de novo GSH synthesis by naphthoquinone-induced oxidative stress is associated with the transcriptional activation of the Gamma GCS-HS gene and the subsequent elevation in Gamma GCS activity. Unlike simpler quinones, DMNQ cannot form a GSH conjugate. Thus, the induction of Gamma GCS-HS gene transcription does not require formation of an electrophile-glutathione conjugate.
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Gamma Glutamylcysteine synthetase and gsh increase in quinone induced oxidative stress in bpaec
American Journal of Physiology-lung Cellular and Molecular Physiology, 1994Co-Authors: Takeo Iwamoto, Henry Jay FormanAbstract:Glutathione (GSH), an important physiological antioxidant, is synthesized de novo by the sequential reactions of Gamma-Glutamylcysteine synthetase (Gamma GCS) and GSH synthetase. In the present stu...
Shelly C Lu - One of the best experts on this subject based on the ideXlab platform.
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differential regulation of Gamma Glutamylcysteine synthetase heavy and light subunit gene expression
Biochemical Journal, 1997Co-Authors: Zongzhi Huang, Shelly C LuAbstract:Gamma-Glutamylcysteine synthetase (GCS) is the rate-limiting enzyme in the biosynthesis of glutathione and is composed of a heavy and a light subunit. Although the heavy subunit is enzymically active alone, the light subunit plays an important regulatory role by making the holoenzyme function more efficiently. In the current study we examined whether conditions which are known to influence gene expression of the heavy subunit also influence that of the light subunit, and the mechanisms involved. Treatment of cultured rat hepatocytes with hormones such as insulin and hydrocortisone, or plating hepatocytes under low cell density increased the steady-state mRNA level of the heavy subunit only. Treatment with diethyl maleate (DEM), buthionine sulphoximine (BSO) and t-butylhydroquinone (TBH) increased the steady state mRNA level and gene transcription rates of both subunits. These treatments share in common their ability to induce oxidative stress and activate nuclear factor kappa B (NF-kappa B). Treatment with protease inhibitors 7-amino-1-chloro-3-tosylamido-2-heptanone (TLCK) or L-1-tosylamido-2-phenylethyl chloromethyl ketone (TPCK) had no influence on the basal NF-kappa B and GCS subunit mRNA levels, but blocked the activation of NF-kappa B by DEM, BSO and TBH, and the increase in GCS heavy subunit mRNA level by BSO and TBH. On the other hand, the DEM-, BSO- and TBH-induced increase in GCS light-subunit mRNA level was unaffected by TLCK and TPCK. Thus only the heavy subunit is hormonally regulated and growth sensitive, whereas both subunits are regulated by oxidative stress. Signalling through NF-kappa B is involved only in the oxidative-stress-mediated changes in the heavy subunit gene expression.
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regulation of Gamma Glutamylcysteine synthetase by protein phosphorylation
Biochemical Journal, 1996Co-Authors: Zongzhi Huang, Shelly C LuAbstract:We previously reported that the activity of Gamma-Glutamylcysteine synthetase (GCS; EC 6.3.2.2), the rate-limiting enzyme in GSH synthesis, can be acutely inhibited approximately 20-40% by agonists of various signal transduction pathways in rat hepatocytes [Lu, Kuhlenkamp, Garcia-Ruiz and Kaplowitz (1991) J. Clin. Invest. 88, 260-269]. We have now examined the possibility that GCS is phosphorylated directly by activation of protein kinase A (PKA), protein kinase C (PKC) and Ca2+/calmodulin-dependent kinase II (CMK). Phosphorylation of GCS was studied using both purified rat kidney GCS and cultured rat hepatocytes by immunoprecipitating the reaction product with specific rabbit anti-(rat GCS heavy subunit) (anti-GCS-HS) antibodies. All three kinases, PKA, PKC and CMK, phosphorylated rat kidney GCS-HS in a Mg(2+)-concentration-dependent manner, with the highest degree of phosphorylation occurring at 20 mM Mg2+. The maximum incorporation of phosphate in mol/mol of GCS was 1.17 for PKA, 0.70 for PKC and 0.62 for CMK. The degree of phosphorylation was correlated with the degree of loss of GCS activity, and no additional inhibition occurred when GCS was phosphorylated by all three kinases, suggesting that the kinases phosphorylated the same site(s). Phosphoamino analysis showed that all three kinases phosphorylated serine and threonine residues. Two-dimensional phosphopeptide mapping demonstrated that all three kinases phosphorylated the same five peptides, both PKA and PKC phosphorylated two other peptides, and only PKA phosphorylated one additional peptide. Phosphorylation of GCS decreased its Vmax for cysteine and glutamate without changing its K(m). Finally, treatment of cultured rat hepatocytes with dibutyryl cAMP and phenylephrine significantly increased the phosphorylation of GCS, suggesting a potentially important physiological role. In summary, we have demonstrated that GCS is phosphorylated and suggest that phosphorylation/dephosphorylation may regulate GCS activity.
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hormonal and cell density regulation of hepatic Gamma Glutamylcysteine synthetase gene expression
Molecular Pharmacology, 1995Co-Authors: Shelly C LuAbstract:We previously reported that the activity of Gamma-Glutamylcysteine synthetase (GCS), the rate-limiting enzyme in GSH synthesis, is under both hormonal and cell density regulation in cultured rat hepatocytes. Specifically, the addition of insulin or hydrocortisone to culture media or the lowering of the initial plating cell density increased cell GSH by increasing the activity of GCS. In the present study, we examined the molecular mechanism of these effects. To determine whether the increase in GCS activity is associated with an increase in GCS heavy subunit (GCS-HS) mRNA expression, the steady state mRNA levels of GCS-HS were examined with the use of Northern blots. After 24-hr treatment of high density (0.6 x 10(5) cells/cm2) cultured rat hepatocytes with insulin (1 micrograms/ml) or hydrocortisone (50 nM), the steady state GCS-HS mRNA level increased by approximately 1-2 fold. When the plating density was decreased to 0.1 x 10(5) cells/cm2, the steady state GCS-HS mRNA level also increased by 1-2 fold 24 hr later. An increase in the steady state GCS-HS mRNA level was found within 4 hr of either hormonal treatment or cell density manipulation. The increase in steady state GCS-HS mRNA level resulted from increased gene transcription, as the transcriptional rates of GCS-HS after hormonal or cell density manipulation were increased by 2-3-fold, whereas the rates of GCS-HS mRNA degradation remained unchanged. Western blotting confirmed the increase in GCS-HS protein level after hormone treatment or lowering of plating cell density. When examined in vivo, the steady state GCS-HS mRNA level decreased by 50% in a rat in which diabetes had been induced with streptozotocin for 1 week; this was prevented with insulin replacement. In summary, GCS-HS gene expression is under both hormonal and cell density regulation.
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insulin and glucocorticoid dependence of hepatic Gamma Glutamylcysteine synthetase and glutathione synthesis in the rat studies in cultured hepatocytes and in vivo
Journal of Clinical Investigation, 1992Co-Authors: Shelly C Lu, Junli Ge, John Kuhlenkamp, Neil KaplowitzAbstract:We reported that glucagon and phenylephrine decrease hepatocyte GSH by inhibiting Gamma-Glutamylcysteine synthetase (GCS), the rate-limiting enzyme in GSH synthesis (Lu, S.C., J. Kuhlenkamp, C. Garcia-Ruiz, and N. Kaplowitz. 1991. J. Clin. Invest. 88:260-269). In contrast, we have found that insulin (In, 1 microgram/ml) and hydrocortisone (HC, 50 nM) increased GSH of cultured hepatocytes up to 50-70% (earliest significant change at 6 h) with either methionine or cystine alone as the sole sulfur amino acid in the medium. The effect of In occurred independent of glucose concentration in the medium. Changes in steady-state cellular cysteine levels, cell volume, GSH efflux, or expression of Gamma-glutamyl transpeptidase were excluded as possible mechanisms. Both hormones are known to induce cystine/glutamate transport, but this was excluded as the predominant mechanism since the induction in cystine uptake required a lag period of greater than 6 h, and the increase in cell GSH still occurred when cystine uptake was blocked. Assay of GSH synthesis in extracts of detergent-treated cells revealed that In and HC increased the activity of GCS by 45-65% (earliest significant change at 4 h) but not GSH synthetase. In and HC treatment increased the Vmax of GCS by 31-43% with no change in Km. Both the hormone-mediated increase in cell GSH and GCS activity were blocked with either cycloheximide or actinomycin D. Finally, when studied in vivo, streptozotocin-treated diabetic and adrenalectomized rats exhibited lower hepatic GSH levels and GCS activities than respective controls. Both of these abnormalities were prevented with hormone replacement. Thus, both in vitro and in vivo, In and glucocorticoids are required for normal expression of GCS.
A Meister - One of the best experts on this subject based on the ideXlab platform.
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amino acid sequence and function of the light subunit of rat kidney Gamma Glutamylcysteine synthetase
Journal of Biological Chemistry, 1993Co-Authors: Chinshiou Huang, Mary E Anderson, A MeisterAbstract:Abstract The heavy subunit (M(r), 72,614) of rat kidney Gamma-Glutamylcysteine synthetase, the enzyme that catalyzes the first step of glutathione (GSH) synthesis, mediates the catalytic activity of this enzyme and its feedback inhibition by GSH. There is evidence that the light subunit has a regulatory function (Huang, C.-S., Chang, L.-S., Anderson, M.E., and Meister, A. (1993) J. Biol. Chem. 268, 19675-19680). In the present work the cDNA for the light subunit was isolated, sequenced, and expressed in Escherichia coli. The cDNA was found to code for a protein of 274 amino acid residues (M(r) 30, 548). Recombinant holoenzyme was obtained by co-expression of the heavy and light subunits and by mixing of the separately expressed proteins. These recombinant holoenzyme preparations exhibit catalytic and GSH feedback inhibitory properties that are virtually identical to those of the isolated holoenzyme. These studies establish that the light subunit is an integral part of the enzyme and that the light and heavy subunits, are coded for separately. Possibly significant similarity of sequence of amino acids was found between the light subunit and E. coli Gamma-Glutamylcysteine synthetase, which is a single polypeptide.
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catalytic and regulatory properties of the heavy subunit of rat kidney Gamma Glutamylcysteine synthetase
Journal of Biological Chemistry, 1993Co-Authors: Chinshiou Huang, Mary E Anderson, Longsen Chang, A MeisterAbstract:Abstract Gamma-Glutamylcysteine synthetase (rat kidney), which catalyzes the first step of GSH synthesis, can be dissociated into subunits (M(r) 73,000 and 27,700) by native gel electrophoresis after treatment with dithiothreitol (DTT); the heavy subunit, which exhibits catalytic activity and feedback inhibition by GSH (Seelig, G. F., Simondsen, R. P., and Meister, A. (1984) J. Biol. Chem. 259, 9345-9347), was cloned and sequenced (Yan, N., and Meister, A. (1990) J. Biol. Chem. 265, 1588-1593). Here, the cDNA for the heavy sub unit was expressed in Escherichia coli, and the recombinant enzyme was separated from E. coli Gamma-Glutamylcysteine synthetase and purified. The recombinant enzyme and the isolated heavy subunit have much lower affinity for glutamate and higher sensitivity to GSH inhibition than the holoenzyme, suggesting that the heavy subunit alone would not be very active in vivo. A GSH analog, Gamma-Glu-alpha-aminobutyryl-Gly (ophthalmic acid), inhibits only slightly, but inhibits much more after treatment of the holoenzyme with DTT. In contrast, ophthalmic acid inhibits the recombinant and isolated heavy subunit enzymes substantially without DTT treatment. We conclude that (a) the light subunit has a regulatory function affecting the affinity of the enzyme for glutamate and GSH and (b) feedback inhibition by GSH involves reduction of the enzyme and also competition between GSH and glutamate for the glutamate site.
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amino acid sequence of rat kidney Gamma Glutamylcysteine synthetase
Journal of Biological Chemistry, 1990Co-Authors: A MeisterAbstract: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.
R T Mulcahy - One of the best experts on this subject based on the ideXlab platform.
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regulation of Gamma Glutamylcysteine synthetase subunit gene expression by the transcription factor nrf2
Journal of Biological Chemistry, 1999Co-Authors: A C Wild, H R Moinova, R T MulcahyAbstract:Abstract Exposure of HepG2 cells to β-naphthoflavone (β-NF) or pyrrolidine dithiocarbamate (PDTC) resulted in the up-regulation of the γ-Glutamylcysteine synthetase catalytic (GCSh) and regulatory (GCSl) subunit genes. Increased expression was associated with an increase in the binding of Nrf2 to electrophile response elements (EpRE) in the promoters of these genes. Nrf2 overexpression increased the activity of GCSh and GCSl promoter/reporter transgenes. Overexpression of an MafK dominant negative mutant decreased Nrf2 binding to GCS EpRE sequences, inhibited the inducible expression of GCSh and GCSlpromoter/reporter transgenes, and reduced endogenous GCS gene induction. β-NF and PDTC exposure also increased steady-state levels of MafG mRNA. In addition to Nrf2, small Maf and JunD proteins were detected in GCShEpRE-protein complexes and, to a lesser extent, in GCSlEpRE-protein complexes. The Nrf2-associated expression of GCS promoter/reporter transgenes was inhibited by overexpression of MafG. Inhibition of protein synthesis by cycloheximide partially decreased inducibility by PDTC or β-NF and resulted in significant increases in GCS mRNA at late time points, when GCS mRNA levels are normally declining. We hypothesize that, in response to β-NF and PDTC, the GCS subunit genes are transcriptionally up-regulated by Nrf2-basic leucine zipper complexes, containing either JunD or small Maf protein, depending on the particular GCS EpRE target sequence and the inducer. Following maximal induction, down-regulation of the two genes is mediated via a protein synthesis-dependent mechanism.
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The induction of GSH synthesis by nanomolar concentrations of NO in endothelial cells: a role for Gamma-Glutamylcysteine synthetase and Gamma-glutamyl transpeptidase.
FEBS letters, 1999Co-Authors: D Moellering, J Mc Andrew, R P Patel, H J Forman, R T Mulcahy, H Jo, V M Darley-usmarAbstract:Nitric oxide protects cells from oxidative stress through a number of direct scavenging reactions with free radicals but the effects of nitric oxide on the regulation of antioxidant enzymes are only now emerging. Using bovine aortic endothelial cells as a model, we show that nitric oxide, at physiological rates of production (1-3 nM/s), is capable of inducing the synthesis of glutathione through a mechanism involving Gamma-Glutamylcysteine synthetase and Gamma-glutamyl transpeptidase. This novel nitric oxide signalling pathway is cGMP-independent and we hypothesize that it makes an important contribution to the anti-atherosclerotic and antioxidant properties of nitric oxide.
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transcriptional up regulation of Gamma Glutamylcysteine synthetase gene expression in melphalan resistant human prostate carcinoma cells
Molecular Pharmacology, 1994Co-Authors: R T Mulcahy, S Untawale, J J GippAbstract:Tumor cell resistance to many chemotherapeutic agents, including alkylating agents, cisplatin, and doxorubicin, is frequently associated with increased intracellular levels of the nonprotein sulfhydryl glutathione (GSH). Recent evidence has demonstrated that increased GSH levels can be accompanied by an increase in the activity of Gamma-Glutamylcysteine synthetase (GCS), which catalyzes the rate-limiting step in de novo synthesis of GSH, and by an increase in the steady state level of mRNA for the catalytic subunit of GCS. Using melphalan-resistant DU 145/M4.5 human prostate carcinoma cells, which express elevated GSH levels, GCS enzyme activity, and GCS mRNA levels, we sought to determine the mechanism(s) responsible for the increased GCS mRNA expression. As determined by Northern analyses and RNase protection assays, the steady state level of GCS message in the resistant cells was increased 10-20-fold, in comparison with the drug-sensitive parent DU 145 cells. No significant difference in gene copy number or evidence of rearrangement was detected in the resistant cell line by Southern analyses. The GCS-specific mRNA isolated from the resistant cells was less stable than that isolated from the drug-sensitive cells (half-lives of 6 hr and 9 hr, respectively), indicating that this difference does not contribute to the increased steady state levels in the resistant cells. Nuclear run-on experiments revealed that the GCS transcription rate in the DU 145/M4.5 cells was increased approximately 12-fold, in comparison with that detected in the DU 145 cells. This difference in transcription rate was comparable in magnitude to the difference in steady state mRNA levels detectable in the two cell populations. Similar correlations between steady state GCS mRNA levels and transcription rates were also observed in other DU 145 lines expressing intermediate degrees of resistance to melphalan and correspondingly intermediate GCS mRNA elevations. These data suggest that GCS expression is transcriptionally regulated in these melphalan-resistant tumor cells.
Eng H Lo - One of the best experts on this subject based on the ideXlab platform.
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Gamma Glutamylcysteine ethyl ester protects cerebral endothelial cells during injury and decreases blood brain barrier permeability after experimental brain trauma
Journal of Neurochemistry, 2011Co-Authors: Wendy Leung, Song Zhao, Stefanie Pallast, Klaus Van Leyen, Xiaoying Wang, Ayfer Yalcin, Eng H LoAbstract:J. Neurochem. (2011) 118, 248–255. Abstract Oxidative stress is a pathway of injury that is common to almost all neurological conditions. Hence, methods to scavenge radicals have been extensively tested for neuroprotection. However, saving neurons alone may not be sufficient in treating CNS disease. In this study, we tested the cytoprotective actions of the glutathione precursor Gamma-Glutamylcysteine ethyl ester (GCEE) in brain endothelium. First, oxidative stress was induced in a human brain microvascular endothelial cell line by exposure to H2O2. Addition of GCEE significantly reduced formation of reactive oxygen species, restored glutathione levels which were reduced in the presence of H2O2, and decreased cell death during H2O2-mediated injury. Next, we asked whether GCEE can also protect brain endothelial cells against oxygen–glucose deprivation (OGD). As expected, OGD disrupted mitochondrial membrane potentials. GCEE was able to ameliorate these mitochondrial effects. Concomitantly, GCEE significantly decreased endothelial cell death after OGD. Lastly, our in vivo experiments using a mouse model of brain trauma show that post-trauma (10 min after controlled cortical impact) administration of GCEE by intraperitoneal injection results in a decrease in acute blood–brain barrier permeability. These data suggest that the beneficial effects of GCEE on brain endothelial cells and microvessels may contribute to its potential efficacy as a neuroprotective agent in traumatic brain injury.
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Gamma‐Glutamylcysteine ethyl ester protects cerebral endothelial cells during injury and decreases blood–brain barrier permeability after experimental brain trauma
Journal of Neurochemistry, 2011Co-Authors: Wendy Leung, Song Zhao, Stefanie Pallast, Klaus Van Leyen, Xiaoying Wang, Ayfer Yalcin, Eng H LoAbstract:J. Neurochem. (2011) 118, 248–255. Abstract Oxidative stress is a pathway of injury that is common to almost all neurological conditions. Hence, methods to scavenge radicals have been extensively tested for neuroprotection. However, saving neurons alone may not be sufficient in treating CNS disease. In this study, we tested the cytoprotective actions of the glutathione precursor Gamma-Glutamylcysteine ethyl ester (GCEE) in brain endothelium. First, oxidative stress was induced in a human brain microvascular endothelial cell line by exposure to H2O2. Addition of GCEE significantly reduced formation of reactive oxygen species, restored glutathione levels which were reduced in the presence of H2O2, and decreased cell death during H2O2-mediated injury. Next, we asked whether GCEE can also protect brain endothelial cells against oxygen–glucose deprivation (OGD). As expected, OGD disrupted mitochondrial membrane potentials. GCEE was able to ameliorate these mitochondrial effects. Concomitantly, GCEE significantly decreased endothelial cell death after OGD. Lastly, our in vivo experiments using a mouse model of brain trauma show that post-trauma (10 min after controlled cortical impact) administration of GCEE by intraperitoneal injection results in a decrease in acute blood–brain barrier permeability. These data suggest that the beneficial effects of GCEE on brain endothelial cells and microvessels may contribute to its potential efficacy as a neuroprotective agent in traumatic brain injury.
