• Environmental Analysis Health and Toxicology
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• 제24권4호
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• pp.303-309
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• 2009

Hepatic antioxidant defense systems were examined in rats treated with tetrabromobisphenol-A (TBBPA), a brominated flame retardant, at the doses of 0, 250, 500 and 1,000 mg/kg for four weeks. Hepatic ratio of glutathione disulfide to glutathione (GSH) and levels of malondialdehyde, oxidative stress markers were not changed in rats treated with TBBPA. Hepatic expression of antioxidant enzymes including GSH peroxdiase-1 (GPX-1)/GSH reductase (GR), alpha-, mu- and pi-class glutathione-S-transferase (GST) and gamma-glutamylcysteine ligase catalytic subunit was determined using immunoblot analysis. Alpha-class GSTs, GPX-1 and GR levels were significantly decreased in rats treated with TBBPA at the dose of 500 or 1,000 mg/kg. These results show that TBBPA results in down-regulation of hepatic expression of antioxidant enzymes related with GSH, suggesting the liver in TBBPA-treated rats may be more sensitive to oxidants.

• Biomolecules & Therapeutics
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• 제24권5호
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• pp.510-516
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• 2016

Isoegomaketone (IK) was isolated from Perilla frutescens, which has been widely used as a food in Asian cuisine, and evaluated for its biological activity. We have already confirmed that IK induced the HO-1 expression via Nrf2 activation in RAW264.7 cells. In this study, we investigated the effect of IK on the mechanism of HO-1 expression. IK upregulated HO-1 mRNA and protein expression in a dose dependent manner. The level of HO-1 mRNA peaked at 4 h after $15{\mu}M$ IK treatment. To investigate the mechanisms of HO-1 expression modulation by IK, we used pharmacological inhibitors for the protein kinase C (PKC) family, PI3K, and p38 MAPK. IK-induced HO-1 mRNA expression was only suppressed by SB203580, a specific inhibitor of p38 MAPK. ROS scavengers (N-acetyl-L-cysteine, NAC, and glutathione, GSH) also blocked the IK-induced ROS production and HO-1 expression. Furthermore, both NAC and SB203580 suppressed the IK-induced Nrf2 activation. In addition, ROS scavengers suppressed other oxidative enzymes such as catalase (CAT), glutathione S-transferase (GST), and NADH quinone oxidoreductase (NQO-1) in IK-treated RAW264.7 cells. Taken together, it can be concluded that IK induced the HO-1 expression through the ROS/p38 MAPK/Nrf2 pathway in RAW264.7 cells.

• Journal of Ginseng Research
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• 제47권2호
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• pp.319-328
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• 2023

Background: Demyelination has been observed in neurological disorders, motivating researchers to search for components for enhancing remyelination. Previously we found that Rb1, a major ginsenoside in Korean Red Ginseng (KRG), enhances myelin formation. However, it has not been studied whether Rb1 or KRG function in remyelination after demyelination in vivo. Methods: Mice were fed 0.2% cuprizone-containing chow for 5 weeks and returned to normal chow with daily oral injection of vehicle, KRG, or Rb1 for 3 weeks. Brain sections were stained with luxol fast blue (LFB) staining or immunohistochemistry. Primary oligodendrocyte or astrocyte cultures were subject to normal or stress condition with KRG or Rb1 treatment to measure gene expressions of myelin, endoplasmic reticulum (ER) stress, antioxidants and leukemia inhibitory factor (LIF). Results: Compared to the vehicle, KRG or Rb1 increased myelin levels at week 6.5 but not 8, when measured by the LFB⁺ or GST-pi⁺ area within the corpus callosum. The levels of oligodendrocyte precursor cells, astrocytes, and microglia were high at week 5, and reduced afterwards but not changed by KRG or Rb1. In primary oligodendrocyte cultures, KRG or Rb1 increased expression of myelin genes, ER stress markers, and antioxidants. Interestingly, under cuprizone treatment, elevated ER stress markers were counteracted by KRG or Rb1. Under rotenone treatment, reduced myelin gene expressions were recovered by Rb1. In primary astrocyte cultures, KRG or Rb1 decreased LIF expression. Conclusion: KRG and Rb1 may improve myelin regeneration during the remyelination phase in vivo, potentially by directly promoting myelin gene expression.

• Bulletin of the Korean Chemical Society
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• 제31권9호
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• pp.2497-2502
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• 2010

Arg13 is a conserved active-site residue in all known Pi class glutathione S-transferases (GSTs) and in most Alpha class GSTs. To evaluate its contribution to substrate binding and catalysis of this residue, three mutants (R13A, R13K, and R13L) were expressed in Escherichia coli and purified by GSH affinity chromatography. The substitutions of Arg13 significantly affected GSH-conjugation activity, while scarcely affecting glutathione peroxidase or steroid isomerase activities. Mutation of Arg13 into Ala largely reduced the GSH-conjugation activity by approximately 85 - 95%, whereas substitutions by Lys and Leu barely affected activity. These results suggest that, in the GSH-conjugation activity of hGST P1-1, the contribution of Arg13 toward catalytic activity is highly dependent on substrate specificities and the size of the side chain at position 13. From the kinetic parameters, introduction of larger side chains at position 13 results in stronger affinity (Leu > Lys, Arg > Ala) towards GSH. The substitutions of Arg13 with alanine and leucine significantly affected $k_{cat}$, whereas substitution with Lys was similar to that of the wild type, indicating the significance of a positively charged residue at position 13. From the plots of log ($k_{cat}/{K_m}^{CDNB}$) against pH, the $pK_a$ values of the thiol group of GSH bound in R13A, R13K, and R13L were estimated to be 1.8, 1.4, and 1.8 pK units higher than the $pK_a$ value of the wild-type enzyme, demonstrating the contribution of the Arg13 guanidinium group to the electrostatic field in the active site. From these results, we suggest that contribution of Arg13 in substrate binding is highly dependent on the nature of the electrophilic substrates, while in the catalytic mechanism, it stabilizes the GSH thiolate through hydrogen bonding.

• 한국식품영양과학회지
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• 제32권8호
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• pp.1328-1336
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• 2003

본 연구는 우리나라에서 발병률이 높은 간암의 발생과정에서 정어리유와 d-limonene의 섭취가 미치는 영향을 세포막 지질조성 및 PKC활성도를 통해 조사하여 이들의 항암 작용관련 기전을 규명 하고자 하였다. 따라서 이유된 흰쥐를 지방산 조성이 아주 다른 옥수수유, 정어리유를 15% 수준으로 공급하고 d-limonene 섭취군은 5%수준으로 공급하여 실험군에서는 발암물질인 DEN을 2회 복강 주사하고 PB를 물에 섞어 주어 20주간 사육하여 membrane fraction의 지방산 조성 및 지질의 조성, glutathione-S-transferase, PKC 활성도를 조사하여 아래와 같은 결과를 얻었다. 간 세포막의 콜레스테롤과 인지질 함량에 대한 C/PL ratio는 옥수수유군에서 발암물질 투여나 d-limonene의 섭취에 따른 효과가 없었으나 정어리 유군에서는 발암물질 투여시, d-limonene 섭취시 유의적인 감소를 나타내어 식이지방의 종류에 따라 발암물질과 d-limonene의 작용이 차이가 있는 것으로 나타났다. Membrane fraction의 인지질 조성은 CL을 제외한 PE, PI, PG, PC, PS와 PE/PC ratio등 모두에 있어서 식이지방의 종류, 발암물질의 투여, d-liomnene섭취에 따른 차이가 나타나지 않았다. 세포막의 지방산 조성을 나타내는 n-6/n-3 ratio가 정어리유군에서 옥수수유군보다 유의적으로 낮았고, 옥수수유군에서는 발암물질 투여나 d-limonene의 섭취에 따라 유의적으로 증가했으나 정어리유군에서는 발암물질과 d-limonene에 의한 차이가 없었다. Cytosolic PKC의 활성은 식이지방의 종류와 발암물질 투여에 따른 차이는 없었고, d-limonene의 섭 취에 따라 유의적 감소를 나타냈으며, 막부착 PKC의 활성은 옥수수유군에서 유의적으로 높았고, d-limonene 섭취에 따라 감소 경향을 발암물질 투여에 따라서는 증가 경향을 보였으나 유의적인 차이를 나타내지는 않았다. GST활성은 식이 지방의 종류에 따른 차이는 없었으나 발암물질 투여와 d-limonene 섭취에 따라 유의적으로 증가하였으며, 발암물질과 d-limonene을 같이 공급시에 더욱 더 유의적으로 증가하였다. 이상의 실험 결과를 종합에 보면 암화과정에 일어나는 지방의 대사가 식이지방의 종류에 따라 차이를 보이며, 특히 정어리유군에서 d-limonene에 의한 C/PL ratio가 감소하여 막 유동성에 변화를 초래하고, 이에 따라 membrane bound enzyme의 활성에 변화를 가져오는 것으로 생각된다. 따라서 식이지방의 종류가 암의 발생에 미치는 영향이 다르고, 막부착 PKC 활성도를 감소시켜 발암을 억제하는 효과가 있으며, 이 효과는 지방의 종류에 따라 차이가 있는 것으로 생각된다. 최근 n-3 지방산이나 d-limonene이 PKC expression을 감소시키고, apopotosis 촉진 단백질의 발현을 증가시켜 tumor cell의 apoptosis를 증가시킨다고 하여 n-3 지방산과 d-limonene의 또 다른 발암억제기전을 설명하고 있다. 그러나 n-3 지방산과 d-limonene의 상호효과에 대한 연구는 부족한 실정이므로 d-limonene과 n-3 지방산의 교호작용에 의한 발암억제 기전에 대해서는 더 많은 연구가 필요하다고 하겠다.

• BMB Reports
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• 제49권7호
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• pp.382-387
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• 2016

Reactive oxygen species generated under oxidative stress are involved in neuronal diseases, including ischemia. Glutathione S-transferase pi (GSTpi) is a member of the GST family and is known to play important roles in cell survival. We investigated the effect of GSTpi against oxidative stress-induced hippocampal HT-22 cell death, and its effects in an animal model of ischemic injury, using a cell-permeable PEP-1-GSTpi protein. PEP-1-GSTpi was transduced into HT-22 cells and significantly protected against H2O2-treated cell death by reducing the intracellular toxicity and regulating the signal pathways, including MAPK, Akt, Bax, and Bcl-2. PEP-1-GSTpi transduced into the hippocampus in animal brains, and markedly protected against neuronal cell death in an ischemic injury animal model. These results indicate that PEP-1-GSTpi acts as a regulator or an antioxidant to protect against oxidative stress-induced cell death. Our study suggests that PEP-1-GSTpi may have potential as a therapeutic agent for the treatment of ischemia and a variety of oxidative stress-related neuronal diseases.

• Asian Pacific Journal of Cancer Prevention
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• 제15권15호
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• pp.6131-6136
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• 2014

Objective: Epidemiology studies have reported conflicting results between glutathione S-transferase Mu-1 (GSTM1), glutathione S-transferase theta-1 (GSTT1) and glutathione S-transferase pi-1 (GSTP1) and ovarian cancer (OC) susceptibility. In this study, an updated meta-analysis was applied to determine whether the deletion of GSTM1, GSTT1 and GSTP1 has an influence on OC susceptibility. Methods: A published literature search was performed through PubMed, Embase, Cochrane Library, and Science Citation Index Expanded database for articles published in English. Pooled odds ratios (ORs) and 95% confidence intervals (95%CIs) were calculated using random or fixed effects models. Heterogeneity between studies was assessed using the Cochrane Q test and $I^2$ statistics. Sub-group analysis was conducted to explore the sources of heterogeneity. Sensitivity analysis was employed to evaluate the respective influence of each study on the overall estimate. Results: In total, 10 published studies were included in the final analysis. The combined analysis revealed that there was no significant association between GSTM1 null genotype and OC risk (OR=1.01, 95%CI: 0.91-1.12). Additionally, there was no significant association between GSTT1 genetic polymorphisms and OC risk (OR=0.98, 95% CI: 0.85-1.13). Similalry, no significant associations were found concerning the GSTP1 rs1695 locus and OC risk. Meanwhile, subgroup analysis did not show a significant increase in eligible studies with low heterogeneity. However, sensitivity analysis, publication bias and cumulative analysis demonstrated the reliability and stability of the current meta-analysis. Conclusions: These findings suggest that GSTs genetic polymorphisms may not contribute to OC susceptibility. Large epidemiological studies with the combination of GSTM1 null, GSTT1 null and GSTP1 Ile105Val polymorphisms and more specific histological subtypes of OC are needed to prove our findings.

• Archives of Pharmacal Research
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• 제29권10호
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• pp.911-920
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• 2006

Phenolic antioxidant butylated hydroxyanisole (BHA) is a commonly used food preservative with broad biological activities, including protection against chemical-induced carcinogenesis, acute toxicity of chemicals, modulation of macromolecule synthesis and immune response, induction of phase II detoxifying enzymes, as well as its undesirable potential tumor-promoting activities. Understanding the molecular basis underlying these diverse biological actions of BHA is thus of great importance. Here we studied the pharmacokinetics, activation of signaling kinases and induction of phase II/III drug metabolizing enzymes/transporter gene expression by BHA in the mice. The peak plasma concentration of BHA achieved in our current study after oral administration of 200 mg/kg BHA was around $10\;{\mu}M$. This in vivo concentration might offer some insights for the many in vitro cell culture studies on signal transduction and induction of phase II genes using similar concentrations. The oral bioavailability (F) of BHA was about 43% in the mice. In the mouse liver, BHA induced the expression of phase II genes including NQO-1, HO-1, ${\gamma}-GCS$, GST-pi and UGT 1A6, as well as some of the phase III transporter genes, such as MRP1 and Slco1b2. In addition, BHA activated distinct mitogen-activated protein kinases (MAPKs), c-Jun N-terminal kinase (JNK), extracellular signal-regulated protein kinase (ERK), as well as p38, suggesting that the MAPK pathways may play an important role in early signaling events leading to the regulation of gene expression including phase II drug metabolizing and some phase III drug transporter genes. This is the first study to demonstrate the in vivo pharmacokinetics of BHA, the in vivo activation of MAPK signaling proteins, as well as the in vivo induction of Phase II/III drug metabolizing enzymes/transporters in the mouse livers.