Recently we described the role of glutathione-S-transferase P-1 (GSTP) expression in regulating Nrf2 transcriptional activity by protein-protein interaction. A functional interplay between Nrf2 and ...GSTP to control glutathione (GSH) biosynthesis, detoxification function and signal transduction through protein Cys glutathionylation can be hypothesized. To explore such interplay the effect of GSTP gene manipulation on the cellular levels and redox of main thiols in murine embryonic fibroblasts (MEFs) was investigated. GSTP knockout MEFs showed increased levels of all the identified forms of thiols that included GSH, GSSG, GSSP, Cys, Cyss, CyssP, HCys, HCyss, HCyssP, γ-GluCys and CysGly.
The exposure to the Se-organic thiol-peroxidase compound Ebselen, further and massively up-regulated GSH, Cys and HCys and their corresponding disulfides in GSTP-KO, but not in wild-type (WT) cells. GSSP (protein glutathionylation), and to a lower extent HCyssP, increased after treatment with Se-organic compounds only in WT cells (confirmed by both HPLC and immunoblot analysis).
These findings confirms the role of GSTP as a feedback component of Nrf2 pathway (control of GSH levels) and identify with an unbiased approach the role of this gene in mediating protein glutathionylation signalling during the exposure to Se-organic thiol-peroxidases.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The oncogene and drug metabolism enzyme glutathione S-transferase P (GSTP) is also a GSH-dependent chaperone of signal transduction and transcriptional proteins with key role in liver carcinogenesis. ...In this study, we explored this role of GSTP in hepatocellular carcinoma (HCC) investigating the possible interaction of this protein with one of its transcription factor and metronome of the cancer cell redox, namely the nuclear factor erythroid 2–related factor 2 (Nrf2).
Expression, cellular distribution, and function as glutathionylation factor of GSTP1-1 isoform were investigated in the mouse model of N-nitrosodiethylamine (DEN)-induced HCC and in vitro in human HCC cell lines. The physical and functional interaction of GSTP protein with Nrf2 and Keap1 were investigated by immunoprecipitation and gene manipulation experiments.
GSTP protein increased its liver expression, enzymatic activity and nuclear levels during DEN-induced tumor development in mice; protein glutathionylation (PSSG) was increased in the tumor masses. Higher levels and a preferential nuclear localization of GSTP protein were also observed in HepG2 and Huh-7 hepatocarcinoma cells compared to HepaRG non-cancerous cells, along with increased basal and Ebselen-stimulated levels of free GSH and PSSG. GSTP activity inhibition with the GSH analogue EZT induced apoptotic cell death in HCC cells. Hepatic Nrf2 and c-Jun, two transcription factors involved in GSTP expression and GSH biosynthesis, were induced in DEN-HCC compared to control animals; the Nrf2 inhibitory proteins Keap1 and β−TrCP also increased and oligomeric forms of GSTP co-immunoprecipitated with both Nrf2 and Keap1. Nrf2 nuclear translocation and β−TrCP expression also increased in HCC cells, and GSTP transfection in HepaRG cells induced Nrf2 activation.
In conclusion, GSTP expression and subcellular distribution are modified in HCC cells and apparently contribute to the GSH-dependent reprogramming of the cellular redox in this type of cancer directly influencing the transcriptional system Nrf2/Keap1.
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•GSTP overexpression and nuclear translocation characterize DEN-induced HCC development.•These changes of GSTP protein are also observed in human HCC cell lines.•Gene transfection-induced GSTP overexpression activates Nrf2 in human liver cells.•GSTP coimmunoprecipitates with Nrf2 and Keap1 in the mouse liver.•Specific multimeric forms of GSTP coimmunoprecipitate with Nrf2.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Our previous study showed remarkable differences in the effect of R-sulforaphane (R-SFN) on the expression of CYPs 19, 1A1, 1A2, and 1B1 in ER(+) MCF7, ER( −) MDA-MB-231, and non-tumorigenic ...immortalized MCF10A (8). This study aimed to evaluate the effect of R-SFN on phase II enzymes induction and expression of AhR, Nrf2, and ERα in the same breast cell lines. The results showed increased expression of GSTP as a result of treatment with R-SFN in breast cancer cells. An increased NQO1 transcript and protein levels were found in all breast cells, with the most significant increase in MCF7 cells. Similarly, the enhancement of Nrf2 expression was noticed in all tested cells. AhR gene transcript and protein were decreased in MCF7 cells. In MDA-MB-231, increased AhR mRNA was not confirmed at the protein level. No differences were found in the expression of ERα. Overall, the results of the present study extended our earlier suggestions on the possible interference of R-SFN with estrogens homeostasis in breast cancer cells differing in ERα status, as well as in non-tumorigenic immortalized breast epithelial cells. While some of R-SFN effects might be beneficial and useful in breast cancer prevention, the others, particularly GSTP induction, may lead to adverse effects.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The present study aims to determine the association between a genetic polymorphism of GSTP1 (rs1695) and the risk of periodontitis. This study used a cross-sectional design and included subjects from ...the South Indian population. A total of 100 individuals enrolled at Saveetha Dental College and Hospital, Tamil Nadu were included in this study. The participants were divided into control (n=50) and periodontitis (n=50) based on clinical examination. Blood samples were collected. Genotyping was performed using specific primers spanning the polymorphic site. The genotypic frequencies for the rs1695 polymorphism were not significantly different between cases and controls.
Glutathione transferases (GSTs) play an important role in retinal pathophysiology. Within this family, the GSTP isoform is known as an endogenous regulator of cell survival and proliferation pathways ...and of cellular responses to oxidative stress. In the present study we silenced GSTP in R28 cells, a retinal precursor cell line with markers of both glial and neuronal origin, and obtained stable clones which were viable and, unexpectedly, characterized by a more neuronal phenotype. The degree of neuronal differentiation was inversely correlated with GSTP residual expression levels. The clone with the lowest expression of GSTP showed metabolic reprogramming, a more favorable redox status and, despite its neuronal phenotype, a sensitivity to glutamate and 4‐hydroxynonenal toxicity comparable to that of control cells. Altogether, our evidence shows that near full depletion of GSTP in retinal precursor cells, triggers neuronal differentiation and prosurvival metabolic changes.
The enzyme glutathione transferase P (GSTP) protects cells from toxic compounds and oxidative stress. We silenced GSTP in R28 cells, a retinal precursor cell line and obtained viable clones unexpectedly characterized by a more neuronal phenotype. These clones provide evidence that reduction of GSTP levels can promote neuronal differentiation and that its near full depletion can trigger prosurvival metabolic changes.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Recent findings suggest a functional interaction of the drug resistance enzyme glutathione S-transferase P (GSTP) with the transcription factor Nrf2, a master regulator of the adaptive stress ...response to cellular electrophiles. The effect of this interaction on the metabolism and redox of cellular thiols was investigated in this study during the exposure to alkylating Se-compounds in murine embryonic fibroblasts (MEFs).
GSTP1-1
gene ablation was confirmed to upregulate Nrf2 activity and to increase Cys uptake and the de novo biosynthesis of reduced glutathione (GSH) that was readily released in the extracellular medium together with other cellular thiols. This latter response was associated with a higher expression of the membrane transporter MRP1 and was markedly stimulated by the treatment with alkylating Se-compounds together with protein S-glutathionylation that was observed to be under the influence of GSTP expression. The response of cellular thiols to Se-compounds was not altered by the transient (SiRNA-induced) or stable inactivation of
NRF2
in
GSTP
competent or
hGSTP1
transfected cells, while defects of GSH biosynthesis, efflux, and redox were observed after
NRF2
silencing in
GSTP
−/−
MEFs. In conclusion,
GSTP
is confirmed to functionally interact with Nrf2 and to have a prominent position in the pecking order of factors that control both the Nrf2-dependent and independent response of cellular thiols to alkylating agents.
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EMUNI, FZAB, GEOZS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Oxidative stress plays an important role in the pathogenesis of acute lung injury (ALI). As a typical post-translational modification triggered by oxidative stress, protein S-glutathionylation (PSSG) ...is regulated by redox signaling pathways and plays diverse roles in oxidative stress conditions. In this study, we found that GSTP downregulation exacerbated LPS-induced injury in human lung epithelial cells and in mice ALI models, confirming the protective effect of GSTP against ALI both in vitro and in vivo. Additionally, a positive correlation was observed between total PSSG level and GSTP expression level in cells and mice lung tissues. Further results demonstrated that GSTP inhibited KEAP1-NRF2 interaction by promoting PSSG process of KEAP1. By the integration of protein mass spectrometry, molecular docking, and site-mutation validation assays, we identified C434 in KEAP1 as the key PSSG site catalyzed by GSTP, which promoted the dissociation of KEAP1-NRF2 complex and activated the subsequent anti-oxidant genes. In vivo experiments with AAV-GSTP mice confirmed that GSTP inhibited LPS-induced lung inflammation by promoting PSSG of KEAP1 and activating the NRF2 downstream antioxidant pathways. Collectively, this study revealed the novel regulatory mechanism of GSTP in the anti-inflammatory function of lungs by modulating PSSG of KEAP1 and the subsequent KEAP1/NRF2 pathway. Targeting at manipulation of GSTP level or activity might be a promising therapeutic strategy for oxidative stress-induced ALI progression.
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•GSTP promotes S-glutathionylation (PSSG) of KEAP1 in acute lung injury (ALI).•GSTP-catalyzed PSSG of KEAP1 activates NRF2 pathway and alleviates ALI.•C434 in KEAP1 is the key PSSG site in this process.•Targeting at GSTP might be a promising therapeutic strategy for ALI.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Epidemiological studies implicate environmental risk factors and epigenetic alterations in the multistage process of hepatocellular carcinoma (HCC) development. However, associations between ...environmental factors and DNA methylation of tumour suppressor genes (TSGs) in HCC development remain ambiguous. Understanding how possible interactions influence risk may provide insights into the complexity of hepato-carcinogenesis. For this study, blood samples were collected from HCC patients (n=90) and healthy volunteers (n=99) from Xiamen (China) and data for selected environmental risk factors e.g., benzoapyrene (BaP), hepatitis B or C virus (HBV or HCV) infection, smoking and alcohol consumption were recorded; factors identified as significantly higher (P<0.05) amongst case subjects compared to controls were identified. In order to assess associations for epigenetic alterations and HCC risk factors, serum DNA methylation of TSGs was quantified using high-resolution melting (HRM) analysis. Our results clearly indicate elevated methylation patterns for detoxification gene glutathione-S-transferase Pi (GSTP) promoter regions in cases compared to control subjects. Additionally, GSTP promoter hypermethylation and BaP diol epoxide-albumin (BPDE-Alb) were positively correlated with HCC incidence. Our epidemiological and in vitro cell model studies indicated that GSTP promoter DNA methylation regulates this gene's expression. Moreover, GSTP also plays an important role in BaP detoxification and potential protective role against BaP-induced liver cell toxicity and hepato-carcinogenesis.
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•Environmental BaP exposure in hepatocellular carcinoma is higher than control.•GSTP gene promoter DNA hypermethylation is frequent in hepatocellular carcinoma.•GSTP gene promoter DNA hypermethylation results in GSTP mRNA expression silence.•GSTP mRNA expression plays important roles against BaP-induced liver cell toxicity.•BaP exposure enhances GSTP methylated subject susceptibility of hepatocarcinogenesis.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Background Sensitization to cockroach is one of the strongest identified risk factors for greater asthma morbidity in low-income urban communities; however, the timing of exposures relevant to the ...development of sensitization has not been elucidated fully. Furthermore, exposure to combustion byproducts, including polycyclic aromatic hydrocarbons (PAHs), can augment the development of allergic sensitization. Objective We sought to test the hypotheses that domestic cockroach allergen measured prenatally would predict cockroach sensitization in early childhood and that this association would be greater for children exposed to higher PAH concentrations. Methods Dominican and African American pregnant women living in New York City were enrolled. In the third trimester expectant mothers wore personal air samplers for measurement of 8 nonvolatile PAHs and the semivolatile PAH pyrene, and dust was collected from homes for allergen measurement. Glutathione-S-transferase μ 1 (GSTM1) gene polymorphisms were measured in children. Allergen-specific IgE levels were measured from the children at ages 2, 3, 5, and 7 years. Results Bla g 2 in prenatal kitchen dust predicted cockroach sensitization at the ages of 5 to 7 years (adjusted relative risk RR, 1.15; P = .001; n = 349). The association was observed only among children with greater than (RR, 1.22; P = .001) but not less than (RR, 1.07; P = .24) the median sum of 8 nonvolatile PAH levels. The association was most pronounced among children with higher PAH levels and null for the GSTM1 gene (RR, 1.54; P = .001). Conclusions Prenatal exposure to cockroach allergen was associated with a greater risk of allergic sensitization. This risk was increased by exposure to nonvolatile PAHs, with children null for the GSTM1 mutation particularly vulnerable.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Nuclear Factor kappa B (NF-κB) is a transcription factor family critical in the activation of pro- inflammatory responses. The NF-κB pathway is regulated by oxidant-induced post-translational ...modifications. Protein S-glutathionylation, or the conjugation of the antioxidant molecule, glutathione to reactive cysteines inhibits the activity of inhibitory kappa B kinase beta (IKKβ), among other NF-κB proteins. Glutathione S-transferase Pi (GSTP) is an enzyme that has been shown to catalyze protein S-glutathionylation (PSSG) under conditions of oxidative stress. The objective of the present study was to determine whether GSTP regulates NF-κB signaling, S-glutathionylation of IKK, and subsequent pro-inflammatory signaling. We demonstrated that, in unstimulated cells, GSTP associated with the inhibitor of NF-κB, IκBα. However, exposure to LPS resulted in a rapid loss of association between IκBα and GSTP, and instead led to a protracted association between IKKβ and GSTP. LPS exposure also led to increases in the S-glutathionylation of IKKβ. SiRNA-mediated knockdown of GSTP decreased IKKβ-SSG, and enhanced NF-κB nuclear translocation, transcriptional activity, and pro-inflammatory cytokine production in response to lipopolysaccharide (LPS). TLK117, an isotype-selective inhibitor of GSTP, also enhanced LPS-induced NF-κB transcriptional activity and pro-inflammatory cytokine production, suggesting that the catalytic activity of GSTP is important in repressing NF-κB activation. Expression of both wild-type and catalytically-inactive Y7F mutant GSTP significantly attenuated LPS- or IKKβ-induced production of GM-CSF. These studies indicate a complex role for GSTP in modulating NF-κB, which may involve S-glutathionylation of IKK proteins, and interaction with NF-κB family members. Our findings suggest that targeting GSTP is a potential avenue for regulating the activity of this prominent pro-inflammatory and immunomodulatory transcription factor.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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