Disease relevance of Gclc

• Phase 1 clinical evaluation of oltipraz has demonstrated its ability to induce GST activity as well as the level of transcripts encoding gamma-glutamylcysteine synthetase (gamma-GCS) and DT-diaphorase in the colon mucosa of individuals at increased risk for colorectal cancer [1].
• The relationship between the rhythm in tissue nonprotein sulphydryl groups (NPSH) and that in 1,2-diamine (trans-I)-cyclohexane oxalatoplatinum (1-OHP) toxicity was investigated in a total of 266 male B6D2F1 mice, using buthionine sulphoximine (BSO), an inhibitor of gamma-glutamylcysteine synthetase [2].

High impact information on Gclc

• This protection was associated with increased gamma-glutamylcysteine synthetase activity and increased stores of reduced glutathione, as well as reduced inflammatory cell activation in inflamed tissues [3].
• MTF-1(-/-) embryos fail to transcribe metallothionein I and II genes, and also show diminished transcripts of the gene which encodes the heavy-chain subunit of the gamma-glutamylcysteine synthetase, a key enzyme for glutathione biosynthesis [4].
• To examine the role of GSH synthesis in development and cell growth, we generated mice deficient in GSH by a targeted disruption of the heavy subunit of gamma-glutamylcysteine synthetase (gammaGCS-HS(tm1)), an essential enzyme in GSH synthesis [5].
• Steady-state RNA levels of the catalytic subunit of gamma-glutamylcysteine synthetase (gamma-GCS), the rate-limiting enzyme in GSH synthesis, are elevated 4-fold in these mice, while those for glutathione synthetase (GSH syn) are elevated 2-fold [6].
• We have focused on one component of this stress response, the up-regulation of gamma-glutamylcysteine synthetase (gamma-GCS) and the preceding molecular events involved in its regulation in an in vivo mouse model [7].

Biological context of Gclc

• In the current study, we investigated the tissue distribution of Gclc and Gclm transcripts, as well as GCLc protein, in the developing mouse embryo [8].
• As an initial first step toward understanding the role of GSH in cellular redox homeostasis, we have targeted a disruption of the mouse Gclc gene [9].
• Therefore, the Gclc(+/-) mouse may be a useful genetic model for mild endogenous oxidative stress [9].
• The nonhomologous Gclc and Gclm genes are located on mouse chromosomes 9 and 3, respectively [9].
• The Gclc(-/-) homozygous knockout animal dies before gestational day 13, whereas the Gclc(+/-) heterozygote is viable and fertile [9].

Anatomical context of Gclc

• Treatment of RAW 264.7 mouse macrophages and mouse peritoneal macrophages with oxLDL (30 microg/mL) induces increased expression of both Gclc and Gclm in vitro [10].
• There was a 2-fold induction in GLCLC: mRNA and protein in the gd 16 yolk sacs at both 3 and 10 ppm MeHg [11].
• Western and Northern blots for Glcl-catalytic (Glclc) and Glcl-regulatory (Glclr) subunits were performed on gd 12 and gd 16 fetuses [11].
• This study demonstrates that platelet-derived growth factor (PDGF) increases transcription of the gamma-glutamylcysteine synthetase (GCS) heavy subunit (GCS-HS) in NIH 3T3 fibroblasts via H2O2 and activation of protein kinase C (PKC) [12].
• In untreated embryos, RT-PCR and Western blotting revealed GLCL heavy subunit (GLCL-H) mRNA and protein only at the blastocyst stage of development [13].

Associations of Gclc with chemical compounds

• Knockout of the mouse glutamate cysteine ligase catalytic subunit (Gclc) gene: embryonic lethal when homozygous, and proposed model for moderate glutathione deficiency when heterozygous [9].
• The mechanism of increasing liver GSH content of (+)clausenamide is mainly due to stimulating the key limiting enzyme gamma-glutamylcysteine synthetase (gamma-GCS) activity for GSH biosynthesis [14].
• Mice treated with buthionine sulfoximine [an effective irreversible inhibitor of gamma-glutamylcysteine synthetase (EC 6.3.2.2) that decreases cellular levels of glutathione markedly] were sensitized to the toxic effects of CdCl2 [15].
• We depleted GSH in the brains of newborn wild-type (WT) and transgenic (Tg) mice overproducing either human Cu/Zn-superoxide dismutase (h-CuZnSOD) or human Bcl2 (h-Bcl-2), by subcutaneous injection of l-buthionine sulfoximine (BSO), a specific inhibitor of gamma-glutamylcysteine synthetase [16].
• The intracellular glutathione concentration could be augmented in EL4 cells when cultured with the cysteine delivery agents 2-oxothiazolidine 4-carboxylate (OTC) and 2-mercaptoethanol (2-ME) and suppressed with the gamma-glutamylcysteine synthetase inhibitor buthionine sulfoximine (BSO) [17].

Regulatory relationships of Gclc

• Thus, the yolk sac is capable of up-regulating Glclc and GSH synthetic capacity in response to MeHg exposure [11].

Other interactions of Gclc

• Site-directed mutagenesis of the AREs within the Gclc and Gclm promoters resulted in a decrease of oxLDL-induced luciferase activity [10].
• Both activities of gamma-glutamylcysteine synthetase and catalase were higher than normal at all times after the irradiation and gradually increased [18].
• However, the activities of glucose-6-phosphate dehydrogenase (G6PDH), Se-glutathione peroxidase (GPX), and gamma-glutamylcysteine synthetase (GCS) were down-regulated to varying degrees in a dose-dependent manner [19].
• The glutathione S-transferase (GST) activity, gamma-glutamylcysteine synthetase (gamma-GCS) activity and glutathione content of the colonic tissues were determined at various time points throughout the experiment [20].
• Depletion of the non-enzymatic antioxidant, glutathione, in a mouse model was produced by inhibiting its rate-limiting enzyme, gamma-glutamylcysteine synthetase, for 7 weeks [21].

Analytical, diagnostic and therapeutic context of Gclc

• Reverse transcription-polymerase chain reaction (RT-PCR) was used for the enzymatic synthesis of cDNA sequences encompassing the open reading frame for the catalytic subunit of mouse kidney glutamate-cysteine ligase (Glclc) [22].

References