Добірка наукової літератури з теми "GLRX3"

Circular RNAs (circRNAs) are novel single-stranded noncoding RNAs that can decoy other RNAs to inhibit their functions. Kaposi’s sarcoma (KS), caused by oncogenic Kaposi’s sarcoma-associated herpesvirus (KSHV), is a highly angiogenic and invasive vascular tumor of endothelial origin commonly found in AIDS patients. We have recently shown that KSHV-encoded viral interferon regulatory factor 1 (vIRF1) induces cell invasion, angiogenesis and cellular transformation; however, the role of circRNAs is largely unknown in the context of KSHV vIRF1. Herein, transcriptome analysis identified 22 differentially expressed cellular circRNAs regulated by vIRF1 in an endothelial cell line. Among them, circARFGEF1 was the highest upregulated circRNA. Mechanistically, vIRF1 induced circARFGEF1 transcription by binding to transcription factor lymphoid enhancer binding factor 1 (Lef1). Importantly, upregulation of circARFGEF1 was required for vIRF1-induced cell motility, proliferation and in vivo angiogenesis. circARFGEF1 functioned as a competing endogenous RNAs (ceRNAs) by binding to and inducing degradation of miR-125a-3p. Mass spectrometry analysis demonstrated that glutaredoxin 3 (GLRX3) was a direct target of miR-125a-3p. Knockdown of GLRX3 impaired cell motility, proliferation and angiogenesis induced by vIRF1. Taken together, vIRF1 transcriptionally activates circARFGEF1, potentially by binding to Lef1, to promote cell oncogenic phenotypes via inhibiting miR-125a-3p and inducing GLRX3. These findings define a novel mechanism responsible for vIRF1-induced oncogenesis and establish the scientific basis for targeting these molecules for treating KSHV-associated cancers.

Human GLRX5 (glutaredoxin 5) is an evolutionarily conserved thiol–disulfide oxidoreductase that has a direct role in the maintenance of normal cytosolic and mitochondrial iron homoeostasis, and its expression affects haem biosynthesis and erythropoiesis. We have crystallized the human GLRX5 bound to two [2Fe–2S] clusters and four GSH molecules. The crystal structure revealed a tetrameric organization with the [2Fe–2S] clusters buried in the interior and shielded from the solvent by the conserved β1-α2 loop, Phe69 and the GSH molecules. Each [2Fe–2S] cluster is ligated by the N-terminal activesite cysteine (Cys67) thiols contributed by two protomers and two cysteine thiols from two GSH. The two subunits co-ordinating the cluster are in a more extended conformation compared with iron–sulfur-bound human GLRX2, and the intersubunit interactions are more extensive and involve conserved residues among monothiol GLRXs. Gel-filtration chromatography and analytical ultracentrifugation support a tetrameric organization of holo-GLRX5, whereas the apoprotein is monomeric. MS analyses revealed glutathionylation of the cysteine residues in the absence of the [2Fe–2S] cluster, which would protect them from further oxidation and possibly facilitate cluster transfer/acceptance. Apo-GLRX5 reduced glutathione mixed disulfides with a rate 100 times lower than did GLRX2 and was active as a glutathione-dependent electron donor for mammalian ribonucleotide reductase.

BackgroundAlthough the mechanisms of palindromic rheumatism (PR) is still unclear, an association between PR and rheumatoid arthritis (RA) has been well recognized in previous studies, with one to two-thirds of PR patients developing RA during a period of follow-up. RNA sequencing (RNA-Seq) is a next-generation sequencing (NGS) method that measures genome-wide RNA abundance. Using RNA-Seq to identify the DEGs between flare PR and active RA could help elucidate the pathogenic mechanisms of PR flare and find novel genes to predict RA progression.ObjectivesThe aim of this study is to identify gene expression signatures between PR flare and active RA using whole blood RNA-seq.MethodsWe collected clinical data, and blood samples from 12 flare PR patients and 12 active RA (defined as DAS28-ESR≥3.2) patients from Taichung Veterans General hospital. We obtained high-quality RNA by using PAXGene tube for whole blood sampling and PAXGene blood RNA Kit to extract RNA. Cuffdiff (Cufflinks option) output was filtered for differentially expressed genes (DEGs) with p-value < 0.05. Gene set enrichment analysis (GSEA) were performed using the GSEA version 4.0.0 with immunologic gene sets (C7 sets containing 4872 gene sets) from The Molecular Signatures Database (MSigDB). According to GSEA web suggestion, a false discovery rate (FDR) < 0.25 with a p-value < 0.05 was considered statistically significant. We obtained rank ordered gene list from GSEA.ResultsWe compared flare PR and active RA using GSEA. Five of the top 12 enrichment in phenotype with flare PR was related to lipopolysaccharide (LPS), which was found in the outer membrane of Gram-negative bacteria. And other pathways were also related to immune response, e.g., B cell, T cell and macrophage. In active RA, the characteristic gene expressions were associated with immune response, such as genes up-regulated in dendritic cells, genes down-regulated in B cell, and genes up-regulated in T cells.We obtained top 3 differential gene expressions in flare PR patients and top 3 differential gene expressions in active RA patients. FCGBP, GLRX3 and RTN4R genes were significantly associated with immune response in flare PR patients. And we observed that 3 genes had statistically significant t-test result (FCGBP, p-value< 0.001; GLRX3, p-value< 0.001; RTN4R, p-value< 0.001) (Figure 1a, 1b and 1c). This result showed that FCGBP, GLRX3 and RTN4R may play an important role on immune response related to flare PR. In active RA patients, 3 genes had statistically significant t-test result (HK3, p-value< 0.001; HIST1H2AI, p-value= 0.002; BST1, p-value<0.001) (Figure 1d, 1e and 1f).Figure 1.Differential gene expressions between flare PR and active RA. (a) FCGBP, (b) GLRX3, (c) RTN4R, (d) HK3, (e) HIST1H2AI, (f) BST1ConclusionGSEA analyses showed that five of the top 12 enrichment in flare PR was related to LPS and other pathways were related to immune responses of B cell, T cell and macrophage. However, in active RA, the characteristic gene expressions included genes up-regulated in dendritic cells, genes down-regulated in B cell, and genes up-regulated in T cells, suggeting different physiological pathways from flare of PR.Disclosure of InterestsNone declared

The BolA gene family member (BOLA1–3) plays an important role in regulating normal and pathological biological processes including liver tumorigenesis. However, their expression patterns as prognostic factors in hepatocellular carcinoma (HCC) patients have not to be elucidated. We examined the transcriptional expressions and survival data of BolA family member in patients with HCC from online databases including ONCOMINE, TCGA, UALCAN, Gene Expression Profiling Interactive Analysis (GEPIA), Kaplan-Meier plotter, SurvExpress, cBioPortal, and Exobase. Network molecular interaction views of BolA family members and their neighborhoods were constructed by the IntAct web server. In our research, we had found that the expression levels of BolA /2/3 mRNA were higher in HCC tissue than in normal liver tissues from TGCA databases. Moreover, the BolA family gene expression level is significantly associated with distinct tumor pathological grade, TMN stage, and overall survival (OS). The BolA family can be considered as prognostic risk biomarkers of HCC. A small number of BolA gene-mutated samples were detected in the HCC tissue. IntAct analysis revealed that BolA1/2/3 was closely associated with the GLRX3 expression in HCC, which is implicated in the regulation of the cellular iron homeostasis and tumor growth. Furthermore, prognostic values of altered BolAs and their neighbor GLRX3 gene in HCC patients were validated by SurvExpress analysis. In conclusion, the membrane BolA family identified in this study provides very useful information for the mechanism of hepatic tumorigenesis.

Cardiovascular diseases are the leading cause of death worldwide, and as rates continue to increase, discovering mechanisms and therapeutic targets become increasingly important. An underlying cause of most cardiovascular diseases is believed to be excess reactive oxygen or nitrogen species. Glutathione, the most abundant cellular antioxidant, plays an important role in the body’s reaction to oxidative stress by forming reversible disulfide bridges with a variety of proteins, termed glutathionylation (GSylation). GSylation can alter the activity, function, and structure of proteins, making it a major regulator of cellular processes. Glutathione-protein mixed disulfide bonds are regulated by glutaredoxins (Glrxs), thioltransferase members of the thioredoxin family. Glrxs reduce GSylated proteins and make them available for another redox signaling cycle. Glrxs and GSylation play an important role in cardiovascular diseases, such as myocardial ischemia and reperfusion, cardiac hypertrophy, peripheral arterial disease, and atherosclerosis. This review primarily concerns the role of GSylation and Glrxs, particularly glutaredoxin-1 (Glrx), in cardiovascular diseases and the potential of Glrx as therapeutic agents.

Abstract Introduction Frontline treatment of patients in chronic phase of chronic myeloid leukemia(CP-CML) is classically based on tyrosine kinase inhibitors (TKI). Imatinib was introduced in 1998, then second- and third-generation TKIs have been developed. This therapeutic arsenal suggest a possible personalized treatment. The choice of TKI could be guided on the one hand by the potential adverse effects depending on the co-morbidities and on the other hand, the efficiency of treatment since an optimal response during the first year is a therapeutic goal (Baccarani M et al. A review of the European LeukemiaNet recommendations for the management of CML. Ann Hematol 2015, 94 Suppl 2:S141-7). Treatment inefficacy may be related to the persistence of quiescent leukemic cells, characterized by a decreased metabolic activity and redox metabolism inducing a low proliferation rate athough the BCR-ABL mutation is present. The level of reactive oxygen species (ROS) being regulated by antioxidant enzymes, we hypothesized that scoring gene expression levels of major antioxidant enzymes could be of clinical interest when considering the response to imatinib. By combining the gene expression profiles of CP-CML patients at the time of diagnosis and their molecular response (BCR-ABL1/ABL1 ratio) at one-year, we determined a theranostic Imatinib-Response Score (IRS) potentially useful to optimize therapeutic decisions (patent # WO2016083742). Methods The expression of antioxidant genes was quantified from blood samples collected from 122 CP-CML patients at diagnosis and 102 healthy volunteers (HealthOx protocol, ClinicalTrials.gov # NCT02789839). Sokal-scores were calculated and all patients were treated with imatinib for at least one year. Quantification of the BCR-ABL1/ABL1 ratio allowed to determine of the one-year response according to the ELN definition (optimal: BCR-ABL1/ABL1 ≤ 0.1%, warning: BCR-ABL1/ABL1 0.1-1%, failure: BCR-ABL1/ABL1 > 1%). RNA extraction was performed after red blood cell lysis and RNA quality was checked with a 2100 Bioanalyzer (Agilent). The expression of antioxidant genes (SOD1, SOD2, SOD3, CAT, TXN, TXN2, GLRX, GLRX2, GLRX3, GLRX5, GPX1, GPX2, GPX3, GPX4, GPX7, GSR, PRDX1, PRDX2, PRDX3, PRDX4, PRDX5, PRDX6) and 3 housekeeping genes (ACTB, B2M, RPL13A) was quantified by RT-qPCR (LightCycler® 480 and UPL technology, Roche). All targets were concomitantly analyzed in triplicates and average values from patients and aged-matched healthy controls were used to determine Relative Quantification (RQ) values by the 2-ΔΔCt method. Mutations in the ABL kinase domain were studied by direct sequencing. IRS were determined by logarithmic logistic regression performed thanks to the glm() function of the stats package (R v3.2.2 software). The generalized linear model was obtained by logistic regression with weighted RQ and was validated by split-sample strategy (10,000 repeats). Samples were divided into two groups ("learning" and "test" groups) randomly mixing optimal responses and failures. Results and conclusion None of the patients had a mutation in the BCR-ABL kinase domain. The expression levels of numerous antioxidant genes were different when considering optimal response and failure to imatinib treatment. A multifactorial strategy by linear combination of normalized RQ values was used to calculate IRS, which allowed for an efficient discrimination between optimal response(IRS = -3.42±1.44) and failure (IRS = 1.76±0.64) (p-value = 1.4 10-9). The probability of one-year response to imatinib was assessed by empirical cumulative distribution function. This function allowed the prediction of optimal response and failure. As expected, the IRS values of patients with a warning response, not used to build the mathematical model (external validation), were located between those of optimal response and failure. Interestingly, the IRS was not correlated with Sokal-score of CP-CML patients (R2= 0.0333), reinforcing its potential usefulness for clinical management. Altogether, this retrospective multicentric study allowed the determination of a molecular score to predict imatinib response. This simple biological strategy using diagnosis blood sample of CP-CML patients will benefit from prospective studies to adapt therapy. Figure. Figure. Disclosures No relevant conflicts of interest to declare.

Abstract Iron is an essential nutrient for every cell in the human body, yet it can also be a potent cellular toxin. Iron is essential because enzymes that require iron co-factors (namely, heme, iron-sulfur clusters, mononuclear and diiron centers) are involved in virtually every major metabolic process in the cell. Hundreds of iron, zinc, copper, and manganese proteins are expressed in human cells, yet little is known about the mechanisms by which these metalloproteins acquire their native metal ligands and avoid mis-metallation. Significant advances have been made in understanding the delivery of iron to iron-dependent enzymes in the cytosol. Poly(rC)-binding proteins (PCBPs) are multifunctional adaptors that mediate interactions between single-stranded nucleic acids, iron cofactors, and other proteins, affecting the fate and activity of the components of these interactions. PCBP1 is an iron-binding protein that delivers iron to ferritin in human cells via a direct protein-protein interaction and can be described as an iron chaperone. PCBP2, a human paralog of PCBP1, is also involved in the delivery of iron to ferritin, both in yeast cells and in human cells, suggesting that PCBP1 and PCBP2 work together in iron delivery. PCBP1 and PCBP2 can also deliver iron to the two major families of non-heme iron enzymes: the mononuclear and dinuclear iron-dependent oxygenases. The prolyl hydroxylases (PHDs) are mononuclear iron enzymes that regulate the degradation of hypoxia inducible factor 1 (HIF1). Misregulation of the HIF transcription factors leads to the development of a variety of cancers in humans. Cells depend on the iron chaperones PCBP1 and PCBP2 to maintain iron in the enzymatic active site of PHDs and the related enzyme, asparagyl hydroxylase and to maintain proper regulation of HIF1a, especially under conditions of iron limitation. Deoxyhypusine hydroxylase (DOHH) is a dinuclear iron enzyme that is required for the posttranslational modification of a single lysine residue on eukaryotic initiation factor 5A (eIF5A). EIF5A and the conversion of this conserved lysine to hypusine are essential in all eukaryotes, as it enables the translation of peptides containing polyproline sequences. We found that cells depleted of PCBP1 or PCBP2 exhibited reduced activity of DOHH, which was due to a loss of iron in the active site of the enzyme. Thus, PCBPs are basic components of a cytosolic iron delivery system that serves both of the major classes of non-heme iron enzymes in the cytosol. Recent work has indicated that a second type of iron delivery system in the cytosol is mediated by a monothiol glutaredoxin, Glrx3, which, in vitro, can bind and transfer iron-sulfur clusters to recipient apo-iron-sulfur proteins. We have determined that PCBP1 directly interacts with Glrx3-containing complexes and can affect the coordination of iron-sulfur clusters by Glrx3. The huge flux of iron through the developing erythroid cell represents unique challenges for the utilization of cellular iron. We have examined the role of PCBPs as iron chaperones in terminal erythroid differentiation. The role of ferritin in erythroid cell maturation is controversial, but our data indicate that ferritin, PCBPs and NCOA4 are critical factors in erythrocyte development. The flux of iron through ferritin via the lysosome appears to be critical for the transfer of iron to mitochondria for heme synthesis. Disclosures No relevant conflicts of interest to declare.

Abstract Abstract 1058 Redox metabolism plays an important role in self-renewal and differentiation of hematopoietic cells and it has been recently established by the Guy Sauvageau's group (Institute for Research in Immunology and Cancer, Montréal, QC) that glutathione peroxydase 3 (GPx-3) promotes competitiveness of Hoxa9-Meis1 induced leukemic stem cells in which Gpx3 overexpression is concomitant of a decrease in H2O2 level and inactivation of p38 MAPK (Herault O et al, ASH annual meeting, 2010 - submitted). Leukemic cells located in the bone marrow (BM) are interacting with a microenvironment which plays a crucial role in the development and progression of leukemia. Mesenchymal stromal cells (MSCs) constitute a population of multipotential cells giving rise to the different hematopoietic microenvironmental cells (adipocytes, osteoblasts, chondrocytes, and vascular-smooth muscle-like hematopoietic supportive stromal cells). The aim of our study was to evaluate the effects of MSC-contact on the GPx-3/H2O2/p38 MAPK axis in human leukemic cells and to assess the cell cycle changes associated with the modification of H2O2 metabolism. BM MSCs were obtained from informed and consenting patients undergoing orthopedic surgery, following a procedure approved by the local ethical committee. Nucleated cells harvested from the iliac crest were seeded (5.104 cells per cm2) in α-MEM supplemented with 10% fetal calf serum (FCS), 20 mmol/l L-glutamine, and 100 units/mL penicillin G. Cells were incubated at 37°C in 95% humidified air and 5% CO2. When fully confluent, the layer of adherent cells was trypsinized (0.25% trypsin-EDTA), and the cells were resuspended in culture medium and seeded at 103 cells per cm2 (passage 1 - P1). BM MSCs were used at P2 in all experiments. The three-lineage mesenchymal differentiation of the BM MSCs used was systematically checked by culturing cells in adipogenic, chondrogenic, and osteogenic induction media as previously described (Delorme et al, Blood 2008, 111:2631). The human KG1a leukemic cell line (FAB M0/M1 CD34+ leukemic cells) was cultured in RPMI 1640 with 20 mmoL/L L-glutamine supplemented with 10% FCS, 100 units/mL penicillin G, and 100 mg/mL streptomycin. KG1a cells were seeded at 1.5 105 cells/cm2 and cocultured with MSCs for 72 h. We have defined two distinct localizations of leukemic cells relative to MSC layer: those in supernatant (non-adherent cells) and cells adhering on the surface of MSCs. The expression of antioxydative enzymes, H2O2 level, p38 MAPK activation (T180/Y182), cell cycle, proliferation and immunophenotype of these two cell fractions were evaluated at day 0 and day 3. The expression of SOD1, SOD2, SOD3, CAT, TXN, TXN2, GLRX, GLRX2, GLRX3, GLRX5, PRDX, PRDX2, PDRX3, PRDX4, PRDX5, PRDX6, GPX1, GPX2, GPX3, GPX4, GPX5, GPX6, GPX7 and GSR antioxydative genes and CDKN1A (p21CIP1) gene was quantified by qRT-PCR (Universal ProbeLibrary, Roche). SDS-PAGE and western-blot experiments were realized to quantify GPx-3 expression and p38 MAPK activation. Flow cytometry studies were performed: (a) to quantify H2O2 level by dichlorodihydrofluorescein diacetate (DCF-DA) staining; (b) to analyze the cell cycle by staining with 7-aminoactinomycin D (7AAD), Alexa Fluor®488-conjugated anti-human Ki67 and Alexa Fluor®488-conjugated anti-phospho-histone H3 (ser10) antibodies; (c) to track the cell divisions with carboxyfluorescein diacetate N-succinimidyl ester (CFSE). Supernatant of MSCs did not modify the GPx-3/H2O2/p38 MAPK axis in KG1a cells. Conversely, when compared with cells in the supernatant of MSCs, adhering KG1a cells were characterized by the exclusive overexpression of GPX3 antioxydative gene, the induction of GPx-3 production, a major decrease in H2O2 concentration and the inactivation of p38 MAPK. These effects were concomitant of cell cycle inhibition: increase in G0 phase, decrease in S and M phase, overexpression of CDKN1A and reduced mitotic activity (CFSE). Altogether these findings suggest that the bone marrow microenvironment plays a key role in the regulation of the oxidative metabolism of leukemic cells by promoting the inhibition of the H2O2/p38 MAPK axis via the induction of GPx-3. Modulation of the GPx-3/H2O2/p38 MAPK pathway by targeting of microenvironmental interactions in leukemia may have clinical relevance and it will be important to verify if these results can be extended in vivo to other models of human leukemias. Disclosures: No relevant conflicts of interest to declare.

Le fer est un élément essentiel à de nombreux processus biologiques. Son homéostasie est maintenue par un mécanisme clos qui se base sur son absorption au niveau de l'intestin, son utilisation par les précurseurs érythroïdes pour produire l’hémoglobine, et son recyclage et stockage dans les macrophages du foie et de la rate. Le métabolisme du fer est sous le contrôle négatif de l'hepcidine, un peptide synthétisé essentiellement par le foie. L'hepcidine inhibe l'absorption intestinale du fer ainsi que son relargage des macrophages. Le déséquilibre du métabolisme du fer entraîne l'apparition de situations pathologiques multiples. En effet, la carence martiale est la cause la plus fréquente d’anémie qui peut être sidéroblastique ou non selon la nature de la disponibilité en fer des précurseurs érythroïdes, et l’excès de fer entraine l’hémochromatose qui peut-être primaire (héréditaire) ou secondaire. Ce projet de thèse consiste à étudier les mécanismes fonctionnels de certaines anomalies, génétiques ou acquises, aboutissant à la surcharge en fer
Iron is an essential element for many biological processes. Its homeostasis is maintained by a closed mechanism based on its absorption in the intestine, its usage by the erythroid precursors for hemoglobin production, and its recycling and storage in the liver and spleen macrophages. Iron metabolism is under the negative control of hepcidin, a small peptide mainly synthesized by the liver. Hepcidin inhibits the intestinal absorption of iron and its release from macrophages. The deregulation of iron balance leads to the appearance of multiple pathological situations. Indeed, iron deficiency is the most frequent cause of anemia which can be sideroblastic or not, and the excess of iron leads to hemochromatosis which may be either primary (hereditary) or secondary. This thesis project consists of studying the functional mechanisms of some abnormalities, inherited or acquired, resulting in iron overload

Human cytosolic monothiolglutaredoxin-3 (GLRX3) is a protein essential for the maturation of cytosolic [4Fe−4S] proteins. We show here that dimeric cluster-bridged GLRX3 transfers its [2Fe−2S]2+ clusters to the human P-loop NTPase NUBP1, an essential early component of the cytosolic iron−sulfur assembly (CIA) machinery. Specifically, we observed that [2Fe−2S]2+ clusters are transferred from GLRX3 to monomeric apo NUBP1 and reductively coupled to form [4Fe−4S]2+ clusters on both N-terminal CX13CX2CX5C and C-terminal CPXC motifs of NUBP1 in the presence of glutathione that acts as a reductant. In this process, cluster binding to the C-terminal motif of NUBP1 promotes protein dimerization, while cluster binding to the N-terminal motif does not affect the quaternary structure of NUBP1. The cluster transfer/assembly process is not complete on both N- and C-terminal motifs and indeed requires a reductant stronger than GSH to increase its efficiency. We also showed that the [4Fe−4S]2+ cluster formed at the N-terminal motif of NUBP1 is tightly bound, while the [4Fe−4S]2+ cluster bound at the C-terminal motif is labile. Our findings provide the first evidence for GLRX3 acting as a [2Fe−2S] cluster chaperone in the early stage of the CIA machinery. Iron-sulfur (Fe-S) clusters are among the most versatile cofactors in biology. Although Fe-S clusters formation can be achieved spontaneously in vitro with inorganic iron and sulfur sources, the in vivo behaviour is more complex and requires the so-called Fe-S biogenesis machineries. In the cytosol, the biogenesis of Fe-S proteins is assisted by the cytosolic Fe-S protein assembly machinery, which comprises at least thirteen known proteins, among which there are human ORAOV1 and YAE1. A hetero-complex formed by the two latter proteins facilitates Fe-S cluster insertion in the human ABC protein ABCE1 within a chain of binding events that are still not well understood. In the present work, ORAOV1 and the YAE1-ORAOV1 complex were produced and their structural and cluster binding properties spectroscopically investigated. It resulted that both ORAOV1 and the YAE1-ORAOV1 complex are characterized by well-structured alpha-helical regions and by unstructured, flexible regions, and are both able to bind a [4Fe-4S]2+ cluster. Bioinformatics and site-directed mutagenesis studies indicated that ORAOV1, and not YAE1, is the protein involved in [4Fe-4S]2+ cluster binding in the hetero-complex. ORAOV1 has indeed a conserved cluster-binding motif able to coordinate a [4Fe-4S] cluster. Overall, our data suggested that the YAE1-ORAOV1 complex might actively participate in the Fe-S cluster insertion into ABCE1 thanks to the [4Fe-4S]2+ cluster binding properties of ORAOV1.

PURPOSE: The Nrf2/Keap1/ARE pathway is a major regulator of cytoprotective responses to oxidants. Gluatredoxin-1 (Glrx-1), a small thiol transferase removes glutathione (GSH) adducts from proteins and participates in redox signaling. Glrx-/- mice exhibit increased protein GSH adducts (PSSG) and non-alcoholic fatty liver disease (NAFLD). Unexpectedly, our Glrx-/- mice showed increased hepatic glutathione (GSH) levels. The Nrf2/Keap1/ARE pathway, as an important regulator of glutathione synthesis, could be regulated by Glrx-1 activity. METHODS: To determine the role of Nrf2 in vivo, we treated Glrx-/- mice with high fat high sucrose (HFHS) diet to induce metabolic and oxidative stress. Livers were harvested at 10 months of age after 8 months on HFHS diet. Gene expression of Nrf2 and its down-signaling targets were determined using RT-qPCR and protein expression was accessed via WB. To determine the role of Nrf2 in Glrx-deficiency in vitro, Glrx siRNA was transfected in HEK293A and HepG2 cells and exposed to high palmitate high glucose (HPHG) to mimic metabolic stress and hydrogen peroxide to mimic oxidative stress. RESULTS: Glrx-/- deficiency increased Nrf2 activity and gene expression, and decreased Keap1 activity and gene expression. Glrx silencing in liver promoted Nrf2 activity and translocation to the nucleus, and downstream targets of Nrf2 were upregulated. CONCLUSION: Our findings indicate that the Nrf2/Keap1/ARE pathway is regulated by Glrx in vitro and in vivo.