Protective effect of overexpression of thioredoxin reductase 1 on hippocampal cells of ovariectomized rats / 中华行为医学与脑科学杂志

Objective:To investigate the effects of thioredoxin reductase 1(TR1) overexpression on hippocampus in ovariectomized SD rats.Methods:Totally 54 female SD rats were divided into normal group, ovariectomized group and ovariectomized over-expressioned TR1 group (ovariectomy-TR1 group) according to the random number table method with 18 in each group. The overexpressed TR1 vector was constructed by lentivirus, and the recombinant lentivirus was injected into the hippocampus by a brain stereotactic instrument.The mRNA levels and protein levels of TR1, Bcl-2, p53 and p21 in the hippocampus of SD rats were detected by qRT-PCR and Western blot.The expression of Caspase-3 in the hippocampus of SD rats was detected by Western blot. The activity of SOD was measured by the WST-1 cell proliferation and cytotoxicity method, the content of GSH was measured by the microplate method, and the content of MDA in the hippocampus of SD rats was measured by the TBA method. The behavioral changes of SD rats were detected by the open field test and water maze test. GraphPad Prism 9.0 was used for statistical analysis.One-way analysis of variance was used for comparisons among the three groups, and the LSD test was used for further pairwise comparisons, the t-test was used to compare the mean number of samples between the two groups. Results:(1) The mRNA and protein levels of TR1 in hippocampus of ovariectomized rats were lower than those of normal rats ( t=3.125, 4.402, both P<0.05). The mRNA and protein levels of TR1 in hippocampus of ovariectomized-TR1 rats were higher than those of ovariectomized rats ( t=4.945, 4.845, both P<0.05). (2) There were significant differences among the three groups in the escape latency in water maze test, the movement distance and the stay time in central area in the open field test ( F=44.73, 33.67, 6.51, all P<0.05), the movement distance in the open field test of ovariectomized rats was more than that of the normal group ((4 700±141) mm, (3 967±163) mm, P<0.05), the stay time in the central area was longer than that of the normal group ((87.33±3.93) s, (80.83±2.48) s, P<0.05), the movement distance ((4 267±150) mm) and the stay time in the central area ((82.17±3.43) s) of ovariectomized-TR1 group were lower than that of ovariectomized group ( P<0.05). In the water maze test, the escape latency of ovariectomized rats was longer than that of the normal group ((28.67±2.50) s, (19.50±2.59) s, P<0.05), and the escape latency in the ovariectomy-TR1 group((25.00±1.67) s) was shorter than that of ovariectomized TR1 group ( P<0.05). (3)There were significant differences in the levels of MDA, SOD and GSH in the hippocampus oxidative stress injury indexes among the three groups ( F=87.41, 91.38, 28.69, all P<0.01). The level of MDA in hippocampus of ovariectomized group was higher than that of normal group, and that in the ovariectomized-TR1 group was lower than that of ovariectomized rats group ( P<0.05). And what's more the levels of SOD and GSH in ovariectomized group were lower than those of normal group ( P<0.05), and the ovariectomized-TR1 group was higher than that of ovariectomized group ( P<0.05). (4) The results of Western blot and RT-PCR showed that the levels of p21 and p53 in hippocampal tissue of ovariectomized group were higher than those of normal group ( P<0.05), while the level of aging-related protein p21 and p53 in ovariectomized-TR1 group were significantly lower than those in ovariectomized group ( P<0.05). The level of apoptotic protein Caspase-3 in the hippocampus of ovariectomized rats was higher than that in the normal group ( P<0.05), while the level of Caspase-3 in ovariectomized-TR1 group was significantly lower than that in ovariectomized rats ( P<0.05). The level of anti-apoptotic protein Bcl-2 in hippocampus of ovariectomized group was lower than that of normal rats ( P<0.05), while the level of Bcl-2 in ovariectomized-TR1 group was significantly higher than that in ovariectomized rats ( P<0.05). Conclusion:Overexpression of TR1 can reduce apoptosis of hippocampal cells by regulating oxidative damage and reducing cell senescence.

Construction and identification of a HEK293 cell line with stable TrxR1 overexpression / 南方医科大学学报

OBJECTIVE@#To construct a HEK293 cell line stably overexpressing TrxR1 as a cell model for functional study of TrxR1 and screening of TrxR1-targeting drugs.@*METHODS@#TrxR1 gene was amplified by PCR and ligated with the lentivirus expression vector pLVX-Puro, which was transformed into Escherichia coli and identified by Sanger dideoxy sequencing. HEK293 cells were infected with the recombinant lentivirus vector (pLVX-Puro-TXNRD1) and screened with Puromycin for cell clones with stable TrxR1 overexpression (HEK293-TrxR1-OE cells). HEK293-TrxR1-OE cells, along with HEK293 cells infected with pLVX-Puro vector (HEK293-NC) and normal HEK293 cells, were tested for mRNA and protein expression levels of TrxR1 using RT-qPCR and Western blotting. TrxR1 enzyme activity in the cells was evaluated with insulin endpoint assay and TRFS-green probe imaging. The sensitivity of the cells to auranofin, a specific TrxR1 inhibitor, was determined with CCK8 assay.@*RESULTS@#TrxR1 gene was successfully inserted into the lentiviral vector pLVX-Puro as confirmed by DNA sequencing. The enzyme activity and mRNA and protein expression levels of TrxR1 were significantly higher in HEK293-TrxR1-OE cells than in HEK293 and HEK293-NC cells (P < 0.005). The inhibitory effects of auranofin on proliferation and cellular TrxR1 enzyme activity were significantly attenuated in HEK293-TrxR1-OE cells as compared with HEK293 and HEK293-NC cells (P < 0.005).@*CONCLUSION@#We successfully obtained a HEK293 cell line with stable TrxR1 overexpression, which shows resistance to auranofin and can be used for screening TrxR1 targeting drugs.

Role of thioredoxin reductase 1 in multidrug resistance caused by reactive oxygen species-related cell apoptosis in hepatocellular carcinoma / 临床肝胆病杂志

Objective Drug resistance is the main cause of chemotherapy failure in hepatocellular carcinoma (HCC), and thioredoxin reductase 1 (TXNRD1), as a major influencing factor for reactive oxygen species (ROS) metabolism, has been proven to be associated with the poor prognosis of patients with HCC. This study aims to explore the role of TXNRD1 in the mechanism of multidrug resistance in HCC. Methods BEL/FU cells in BEL-7402 cell line were selected as the multidrug-resistant cell line. The siRNA was used for the intervention of TXNRD1 expression; quantitative real-time PCR and Western blotting were used to measure the expression of TXNRD1; CCK-8 assay and flow cytometry were used to evaluate the effect of TXNRD1 on hepatocyte ROS accumulation, resistance to 5-fluorouracil (5-Fu) and doxorubicin (DOX), and apoptosis in vitro; a xenograft tumor model was established to investigate the effect of auranofin (AUR) on drug resistance in vivo. The two-independent-samples t test was used for comparison of continuous data between two groups. Results As a multidrug-resistant HCC cell line, BEL/Fu showed high mRNA and protein expression levels of TXNRD1 (both P < 0.05). Compared with 5-Fu or DOX treatment alone, the TXNRD1 inhibitor AUR combined with 5-Fu or DOX had had a significant reduction in the number of colony formation ( P < 0.01) and a significant increase in apoptosis ratio ( P < 0.001). The ROS scavenger N-acetylcysteine (NAC) significantly weakened the effect of TXNRD1 knockdown by siRNA on the drug resistance of BEL/Fu cells, and the application of NAC effectively reduced the apoptosis ratio of cells after siRNA interference ( P < 0.001). Animal experiments also confirmed that compared with the nude mice treated with 5-Fu alone, the nude mice treated with 5-Fu and AUR had a significantly lower tumor mass ( P < 0.001) and a significantly smaller tumor volume ( P < 0.001). Conclusion TXNRD1 plays an important role in the drug resistance of HCC, and inhibition of its level in cells can effectively improve drug resistance. As a TXNRD1 inhibitor, AUR has great application prospects in the multimodality therapy for HCC.

Research progress of thioredoxin system / 国际生物医学工程杂志

The thioredoxin system is composed of thioredoxin (Trx), thioredoxin reductase (TR) and reduced nicotinamide adenine dinucleotide phosphate. Trx is an important antioxidant molecule that can resist cell death caused by various stresses and plays a prominent role in redox reactions. TR is a protein containing selenium (selenocysteine), mainly in three forms, i.e. TR1, TR2 and TR3. TR1 mainly distributed in the cytoplasm, TR2 mainly distributed in the mitochondria, and TR3 mainly distributed in the testes. TR can regulate cell growth and apoptosis. After the cell becomes cancerous, the expression of TR increases to promote cell growth and metastasis. Trx system is closely related to neurodegenerative diseases, parasitic infections, acquired immunodeficiency syndrome, rheumatoid arthritis, hypertension, myocarditis and so on. The Trx system can remove the reactive oxygen species (ROS) in the body, keep the inside and outside of the cell in a balanced state, and it interacts with the thioredoxin interacting protein (TXNIP), which plays an important role in the regulation of glucose metabolism and tumor treatment. The Trx system is an important target for drug treatment of many diseases. In this paper, the research progress of the thioredoxin system was reviewed.

Selenoprotein thioredoxin reductase mediated menadione reduction: catalytic properties & inhibition effects / 生物工程学报

Thioredoxin reductase (TrxR) is one class of the most important antioxidant selenoproteins and is involved in regulating tumor genesis and progression. It has been reported that naphthoquinones can target and inhibit TrxR1 activity therefore produce reactive oxygen species (ROS) mediated by TrxR1, resulting into cellular redox imbalance and making the naphthoquinone compounds to become potential antitumor chemotherapy drugs. The purpose of this work is to explore the interaction between TrxR1 and menadione using biochemical and mass-spectrometric (MS) analyses, to further reveal the detailed mechanisms of TrxR1-mediated naphthoquinone reduction and inhibition of TrxR1 by naphthoquinone compounds. Using the site-directed mutagenesis and recombinantly expressed TrxR1 variants, we measured the steady-state kinetic parameters of menadione reduction mediated by TrxR1 and its variants, performed the inhibition analysis of menadione on TrxR1 activity, and eventually identified the interaction between menadione and TrxR1 through MS analysis. We found that Sec-to-Cys mutation at residue of 498 significantly enhanced the efficiency of TrxR1-mediated menadione reduction, though the Sec⁴⁹⁸ is capable to catalyze the menadione reduction, indicating that TrxR1-mediated menadione reduction is dominantly in a Se-independent manner. Mutation experiments showed that Cys⁴⁹⁸ is mainly responsible for menadione catalysis in comparison to Cys⁴⁹⁷, while the N-terminal Cys⁶⁴ is slightly stronger than Cys⁵⁹ regarding the menadione reduction. LC-MS results detected that TrxR1 was arylated with one molecule of menadione, suggesting that menadione irreversibly modified the hyper-reactive Sec residue at the C-terminus of selenoprotein TrxR1. This study revealed that TrxR1 catalyzes the reduction of menadione in a Se-independent manner meanwhile its activity is irreversibly inhibited by menadione. Hereby it will be useful for the research and development of naphthoquinone anticancer drugs targeting TrxR1.

Effect of auranofin combined with antineoplastic vorinostat on bactericidal activities against gramnegative bacteria and study on the target of auranofin / 中华传染病杂志

Objective To find the target of auranofin with the antibacterial activity against gramnegative bacteria and to investigate the effect of the combination of auranofin and vorinostat on the antibacterial activity against gram-negative bacteria.Methods The strains of E.coli lacking thioredoxin reductase (TrxR)was used to find the target gene.The potential synergies of the combination of auranofin and vorinostat for E.coli strain,A.baumannii strain,P.aeruginosa strain,K.pneumonia strain and muhidrug-resistant (MDR)A.baumannii strain were evaluated using susceptibility tests,micro-dilution checkerboard tests and time-kill studies.The genes related to Trx (trxA,trxB,trxC) and the gene expressed glutathione (gor) of E.coli BW25113 strains (WT) were separately knocked out to observe the effect of auranofin on minimum inhibitory concentration (MIC) and the time-kill kinetics of △trxC and △gor.Furthermore,the complemented strains (C-trxA,C-trxB,C-trxC,C-gor) were used to verify and define the genetic targets.Results According to the results of susceptibility tests,MICs of auranofin were 64 mg/L for E.coli strain BW25113 and K.pneumonia strain ATCC 43816,128 mg/L for P.aeruginosa strain PA14 and 32 mg/L for both A.baumannii strain ATCC 17978 and A.baumannii strain AB5075.However,MICs of vorinostat are 512 mg/L for all isolates.The fractional inhibitory concentration indexes (FICIs) of the combination of auranofin and vorinostat for E.coli strain BW25113,A.baumannii strain ATCC 17978,MDR A.baumannii strain AB5075,K.pneumonia starin ATCC 43816 and P.aeruginosa strain PAl4 were 0.313,0.375,0.375,0.375,and 0.375,respectively,with all values ＜ 0.5,which showed synergy.In susceptibility tests of knockout strains,MICs of auranofin for △trxC increased from 64 mg/L to 256 mg/L,decreased to 16 mg/L for △gor,and no changes for △trxA and △trxB.Auranofin showed the same antibacterial activities against the complemented strains (C-trxC,C-gor) and E.col BW25113,which decreased by about 1.8 lg colong formins units (CFU)/mL of bacterial counts.However,the antibacterial activity of auranofin was significantly reduced for △trxC,and decreased by ＜ 1 lg CFU/mL of bacterial counts.For Agor,bacterial counts decreased 4.6 lg CFU/mL,and the antibacterial activity markedly increased.Conclusions The potential target gene of auranofin against gram-negative bacteria could be trxC,which provides new ideas and methods for the clinical treatment of multidrug-resistant gram-negative bacteria.

Novel thioredoxin reductase inhibitor butaselen inhibits tumorigenesis by down-regulating programmed death-ligand 1 expression / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

The thioredoxin system plays a role in a variety of physiological functions, including cell growth, differentiation, apoptosis, tumorigenesis, and immunity. We previously confirmed that butaselen (BS), a novel thioredoxin reductase inhibitor, can inhibit the growth of various human cancer cell lines, yet the underlying mechanism remains elusive. In this study, we investigated the anti-tumor effect of BS in vivo through regulating the immune system of KM mice. We found that BS inhibits tumor proliferation by promoting the activation of splenic lymphocytes in mice. BS can elevate the percentage of CD4-CD8+ T lymphocytes and the secretion of downstream cytokines in mice via down-regulating the expression of programmed death-ligand 1 (PD-L1) on the tumor cells' surface in vivo. Further study in HepG2 and BEL-7402 cells showed that decrease of PD-L1 level after BS treatment was achieved by inhibiting signal transducer and activator of transcription 3 (STAT3) phosphorylation. Taken together, our results suggest that BS has a role in promoting the immune response by reducing PD-L1 expression via the STAT3 pathway, and subsequently suppresses tumorigenesis.

Research progress of thioredoxin reductase 2 in malignant tumor / 实用肿瘤学杂志

Thioredoxin reductase (TrxR),a family of antioxidant family member,is widely distributed in the body.Its main function is to regulate the redox status of enzymes and transcription factors at the cellular level,and to participate in cell growth,pro-liferation and apoptosis.Meanwhile,it also provides favorable conditions for the occurrence and deterioration of malignant tumors.TrxR has three kinds of isoenzymes.TrxR2 distributed in mitochondria is also up-regulated in most malignant tumors and its expression is much higher than that in paracancerous tissues and normal tissues in recent studies.In addition,there is a lot of correlation between the up-regulated expression of TrxR2 and clinicopathological features as well as prognosis of many malignant tumors.It is speculated that TrxR2 may be involved in the occurrence, deterioration and metastasis in malignant tumors.This article reviews the progress of TrxR2 in several malignancies to explore whether or not TrxR2 can be a biomarker of malignancy and serve as a novel target for oncol-ogy treatment.

Advances in thioredoxin reductase and its inhibitors / 中国药科大学学报

@#Thioredoxin reductase(TrxR)is a seleniferous homodimeric flavoenzyme, which is ubiquitously expressed in all cells and plays a crucial role in the redox regulation of numerous celluar signaling pathways involved in cell survival and proliferation. TrxR maintains cellular redox equilibrium. Recent researches have illuminated that TrxR overexpressed in many tumors, is closely associated with the evolution, progression and apoptosis of tumor. TrxR contains a reactive and solvent accessible selenocysteine residue which is located on a flexible C-terminal arm of the protein. This selenocysteine is essentially involved in the catalytic cycle of TrxR and thus represents an attractive binding site for inhibitors. The TrxR inhibitors as novel target-drug in cancer therapy have been extensively studied and elucidated. This article summarized the latest progress in TrxR inhibitors according to the binding capacity of TrxR and substrate.

Expression of thioredoxin reductase 1 in liver and peripheral blood of human and rats exposed to airborne arsenic through coal-burning / 中华地方病学杂志

Objective To study the expression and enzyme activity of thioredoxin reductase 1 (TrxR1) in liver and peripheral blood of human and rats exposed to airborne arsenic through coal-burning as well as its role in liver injury of coal-burning-borne arsenic poisoning.Methods This study was divided into 2 parts.Part 1 was a population study:133 local residents exposed to airborne arsenic through coal-burning were selected as arsenic exposure groups including a non-patient group (25 cases),no obvious hepatopathy group (38 cases),mild (43 cases) and moderate to severe hepatopathy groups (27 cases) from areas affected by endemic arsenism in Guizhou Province.Thirty-four healthy residents from arsenic not affected areas were selected as controls.Peripheral blood samples were collected from all these people.The expression of TrxR1 mRNA was determined by real-time fluorescence quantitative PCR (qPCR),and enzyme activity of TrxR was tested by visible spectrophotometry.Part 2 was an animal experiment study:Thirty Wistar rats,weighing about 80-100 g,were divided into control group,drinking-waterborne arsenic poisoning group and coal-burning-borne arsenic poisoning group (including low,medium and high arsenic contaminated grain groups) by means of a table of random number according to body mass,6 rats in each group.The control group was fed with normal diet for 3 months; drinking-water-borne arsenic poisoning group and coal-burning-borne arsenic poisoning group were fed with 10 mg/kg As2O3 solution and different concentrations(25,50,100 mg/kg) of arsenic-containing feed,respectively,for 3 months.The expression of TrxR1 mRNA was determined by qPCR; protein expression level of TrxR1 in liver tissue was detected by immunohistochemistry,and enzyme activity of TrxR in serum and liver tissue was tested by visible spectrophotometry.Results The mRNA expressions of TrxR1 in peripheral blood were 1.599 8 (1.128 9-2.156 8),1.469 3 (1.146 1-1.976 3),1.203 6 (0.463 1-1.816 2) and 0.912 3(0.631 8-1.535 0),respectively,among non-patient group,no obvious hepatopathy group,mild and moderate to severe hepatopathy groups.Compared to the control group[1.649 7(1.161 1-2.380 2)],the differences were significant statistically in mild and moderate to severe hepatopathy groups (all P ＜ 0.05).The enzyme activity of TrxR in peripheral blood was (3.12 ± 0.76),(2.81 ± 0.84),(2.52 ± 0.73),(2.42 ± 0.76)U/ml,respectively,in those corresponding groups.Compared to the control group [(3.02 ± 0.70)U/ml],the differences were significant statistically in mild and moderate to severe hepatopathy groups (all P ＜ 0.05).The mRNA expressions of TrxR1 in peripheral blood were 1.05 ± 0.14,1.18 ± 0.18,1.04 ± 0.10 and 0.97 ± 0.13,respectively,among drinking-water-borne arsenic poisoning group,low,medium and high arsenic contaminated grain groups; all of which were lower than that in the control group (1.23 ± 0.15,all P ＜ 0.05) except that of the low arsenic contaminated grain group.The mRNA expressions of TrxR1 in liver tissue were 0.78± 0.10,0.83 ± 0.10,0.79 ± 0.09 and 0.77 ± 0.11,respectively; all of which were lower than that in the control group (0.94 ± 0.12,all P ＜ 0.05).The protein expression of TrxR1 in liver tissue was 310.33 ± 38.81,312.50 ± 23.36,305.67 ± 20.57 and 298.17 ± 23.52,respectively,among the arsenic poisoning groups; all of which were lower than that in the control group (348.50 ± 32.35,all P ＜ 0.05).The enzyme activity of TrxR in serum was (4.22 ± 0.73),(4.86 ± 0.63),(4.04 ± 0.57),(3.73 ± 0.64)U/ml,respectively; all of which were lower than that in the control group [(9.52 ± 1.08)U/ml,all P ＜ 0.05].The enzyme activity of TrxR in liver tissue was (14.82 ± 1.67),(18.76 ± 2.76),(14.90 ± 2.17),(11.55 ± 1.74) U/mg,respectively; all of which were lower than that in the control group [(23.71 ± 3.05)U/mg,all P ＜ 0.05].Conclusion Arsenic aggravates liver injury of coal-burning arsenic poisoning through down-regulating the expressions of TrxR1 mRNA and protein and reducing its enzyme activity as well.

Expression levels and effects of thioredoxin reductase-1 on non-small cell lung cancer / 临床与实验病理学杂志

Purpose To explore the expression of thioredoxin reductase-1 ( TrxR1 ) in non-small cell lung cancer and to observe the effects of TrxR1 on non-small cell lung cancer ( NSCLC) . Methods Immunohistochemistry was used to determine the expression of TrxR1 in 118 NSCLC tissues and 27 normal lung tissues, and to analyze its relationships with clinical pathological features. TrxR1 mR-NA levels were measured by quantitative RT-PCR in 13 cases of NSCLC and 4 cases of normal lung tissue. TrxR1 protein and its mR-NA levels were assessed by Western blotting and quantitative RT-PCR in normal lung epithelial cells and different lung cancer cell lines. After the silence TrxR1 expression in A549 cells, the changes of proliferation were compared. Results The data of immunohis-tochemistry and quantitative RT-PCR showed the overexpression of TrxR1 in NSCLC ( P <0. 05 ) . After using shRNA silencing of TrxR1 in lung cancer cells, cell proliferation changed significantly. Conclusion There are a high mRNA and protein levels of TrxR1 in NSCLC. TrxR1 may be a critical therapeutic target for the treatment in NSCLC.

Detection of Aspergillus fumigatus thioredoxin reductase GliT antigen-specific T cells by ELISPOT assay in healthy individuals and result evaluation / 医学研究生学报

Objective The purpose of this study was to evaluate the protective potential of the Aspergillus fumigatus thiore -doxin reductase GliT ( TR) antigen by establishing and optimizing ELISPOT assay for TR antigen-specific T cells ( TR/AST) secreting IFN-γand IL-4 in peripheral blood mononuclear cells ( PBMCs ) and explore the role of TR/AST in invasive aspergillosis ( IA ) . Methods We optimized the reaction conditions of ELISPOT by preliminary checkerboard titration and determined the frequencies of positive spot-forming cells ( SFCs) specifically secreting IFN-γand IL-4 in the PBMCs of 20 healthy individuals with TR as specific stimulant and with PHA and PMA as positive controls ,. Results Checkerboard titration demonstrated the best result of ELISPOT with the TR antigen at the final concentration of 10μg/well and PBMCs at 3 ×105/well.The median frequency of IFN-γSFCs was sig-nificantly higher (15 [3.5, 59.5]) than that of IL-4 SFCs (0 [0, 0]) (P20/3 ×105 PBMCs), accounting for 45%, but failed to induce IL-4 response in 19 of the healthy individuals . Conclusion The Aspergillus fumigatus TR antigen could induce an immunodominant Th1 response , and therefore might be a potential protective antigen .

Expression of thioredoxin reductase in myeloid leukemia and its significance / 肿瘤研究与临床

Objective To explore the expression of thioredoxin reductase (TrxR) mRNA and protein,as well as the relationship between TrxR and myeloid leukemia.Methods Bone marrow samples from 20 acute myeloid leukemia (AML),20 chronic myeloid leukemia (CML),and 20 healthy persons as normal control group were collected.The human non small cell lung cancer A549 cells were selected as the positive control group.The expression of TrxR mRNA was detected by real-time quantitative polymerase chain reaction.The expression of TrxR protein level was detected by Western blot.Results The relative quantitation expressions of TrxR mRNA were 6.751 (13.459),4.321 (11.389),18.477 (2.089),1.045 (0.467) in AML,CML,positive control and normal control group,were 17.814±3.979 and 4.860±1.550 in the primary diagnosed/relapse group and complete remission (CR) group of AML patients,and were 19.552 (5.758) and 3.459 (2.047) in the primary diagnosed and treatment group of CML patients.The expression levels of TrxR mRNA in AML,CML and positive control group were significantly higher than that in normal control group (H =43.978,P ＜ 0.001).For AML patients,the expression levels of TrxR mRNA in the primary diagnosed/relapse group,CR,positive control group were significantly higher than that in normal control group (F=246.793,P ＜ 0.001),and the difference between the primary diagnosed/relapse group and positive control group was no significant (P ＞ 0.05).The expression of TrxR mRNA were higher in the primary diagnosed/relapse group than that in CR group,and that in CR group than that in normal control group (both P ＜ 0.05).For CML patients,the expression levels of TrxR mRNA in the primary diagnosed,treatment,positive control group were significantly higher than that in normal controls (H =38.222,P ＜ 0.001),the difference between that in the primary diagnosed and that in positive control group was no significant difference (P ＞ 0.05),but the expression of TrxR were significantly higher in the primary diagnosed group than that in treatment group,and that in treatment group than that in normal controls (both P ＜ 0.05).The expression of TrxR mRNA in the primary diagnosed/relapse group of AML and the primary diagnosed group of CML showed no significant difference (P ＞ 0.05).The positive levels of TrxR protein were 0.679,0.606,0.877 and 0.095 in AML,CML,positive control and normal control group.TrxR protein was highly expressed in myeloid leukemia patients.Conclusion The expression levels of TrxR mRNA and protein are increased in myeloid leukemia.The low expression of TrxR in normal hematopoietic stem cells is highly expressed in myeloid leukemia,and is downgraded after treatment,which may be used as one of the parameters to diagnosis,effect and prognosis of myeloid leukemia.

Expression of nuclear factor erythroid-2 related factor 2 in chronic myeloid leukemia and its correlation with thioredoxin reductase / 白血病·淋巴瘤

Objective To investigate the expression of nuclear factor erythroid-2 related factor 2 (Nrf2) gene in chronic myeloid leukemia (CML) and explore its relationship with clinical characteristics and thioredoxin reductase (TrxR).Methods The expressions of Nrf2 and TrxR genes in bone marrow cells and K562 cells were analyzed in 30 bone marrow preparations of CML patients in different phases,including 20 in chronic phase,3 in accelerated phase,7 in blastic phase by real-time quantitative polymerase chain reaction.Ten health subjects were served as normal controls.Results The relative quantitation expression of Nrf2 and TrxR mRNA were 5.601±1.069 and 9.017±2.398 in chronic phase,1.698±0.349 and 5.590±1.015 in accelerated phase,1.252±0.807 and 5.050±1.469 in blastic phase,1.377± 0.344 and 1.867±0.977 in normal controls.The expressions of both Nrf2 and TrxR mRNA in CML had significant differences from those of the normal controls (x2 =14.680,P =0.002,x2 =8.271,P =0.041).The expression of Nrf2 mRNA in accelerated phase,blastic phase group showed no significant difference (Z =0.011,P =0.496),but lower than that in chronic phase group (Z =2.155,P =0.016,Z =2.534,P =0.006).The difference between the first visit and post-treated group was significant (Z =2.015,P =0.022).The expression in K562 cells and normal controls had significant difference (Z =1.898,P =0.029).In CML patients,the expression of Nrf2 was positively correlated with that of TrxR (r =0.738,P =0.037).Conclusion The expression of Nrf2 gene is higher in the first visit group of CML than that in the other groups,and is decreased after therapy,which may be the molecular marker predicting the progress of CML.Nrf2 mRNA expression level is correlated with TrxR.

Expression of 8-hydroxy-2-deoxy guanosine, thioredoxin reductase 1 and glutathione peroxidase 1 in myocardium of autopsy patients with Keshan disease / 中国地方病学杂志

Objective In this study,we investigated the relationship between oxidative stress,selenoproteins level and onset of Keshan disease (KD) through detecting the expression of 8-hydroxy-2-deoxy guanosine (8-OH-dG),thioredoxin reductase 1 (TrxR1) and glutathione peroxidase 1 (GPx1) in myocardial tissue.Methods Myocardium samples of autopsy patients including 8 cases of KD (KD group included 4 acute KD and 4 chronic KD) and 9 cases of non-KD (control group) were immunohistochemically stained for 8-OH-dG,TrxR1 and GPx1.The staining intensities subsequently quantified by using Olympus Image-Pro Plus 6.0 software.Results The positive rate of 8-OH-dG expression in myocardial nuclei was higher in the case group[(68.6 ± 20.4)％] than that of the control group[(2.4 ± 1.5)％,t =8.515,P ＜ 0.05].In addition,the positive rate of 8-OH-dG expression in acute KD[(91.7 ± 3.7)％] was significantly higher than that of chronic KD[(53.2 ± 7.9)％,t =6.409,P＜0.05].The distribution of TrxR1 and GPx1 was not associated with the distribution of myocardial damage.The expression of these two selenoproteins in KD group (401340 ± 59865,497590 ± 197082) were both lower than that of control group(2790300 ± 379298,1348400 ±615840; t =-28.493,-6.016,respectively,all P＜0.01).Conclusions Oxidative damage is detected in myocardium tissue of KD,and 8-OH-dG expression is associated with the degree of myocardial damage in KD.Selenoproteins,TrxR1 and GPx1,may be closely related to the pathogenesis of KD.

Effects of selenium and protein on cardiac morphology and expression of cellular glutathione peroxidase and mitochondrial thioredoxin reductase in rat myocardium / 中国地方病学杂志

Objective To study the effects of selenium(Se) and protein on cardiac morphology and expression of cellular glutathione peroxidase(GPX1 ) and mitochondrial thioredoxin reductase(TR2) in rat myocardial tissue.MethodsSixty healthy weaning male Wistar rats were randomly divided into four groups by two factors two levels factorial design(n =15).Drinking water was divided into two levels of Se-deficient(0 mg/L) and Se-adequate (0.25 mg/L); diet was divided into two levels of protein-deficeient (10％ protein and 0.008 mg/kg Se) and protein-adequate(20％ protein and 0.015 - 0.026 mg/kg Se).The rats were killed after feeding for one year.Pathological changes in myocardial tissues were observed under light microscope.The expression of GPX1 and TR2 in rat myocardial tissue was detected by immunohistochemistry and Western blotting.Results Compared between groups,the difference of the rate of myocardial necrosis in rats was statistically significant(x2 =11.04,P ＜ 0.05),in which Se-deficient protein-deficient group [66.7％ (8/12) ] was significantly higher than Se-adequate proteinadequate group [ 7.1％ ( 1 / 14),x2 - 11.06,P ＜ 0.05 ].GPX 1 positive rates in Se-deficient protein-deficient group,Se-adequate protein-deficient group,Se-deficient protein-adequate group and Se-adequate protein-adequate group were 0(0/12),81.8％(9/11 ),10.0％(1/10) and 100.0％(14/14),respectively,in rat myocardial tissue determined by immunohistochemistry.Of which,Se-adequate protein-deficient group and Se-adequate protein-adequate group were significantly higher than Se-deficient protein-deficient group and Se-deficient protein-adequate group(x2 =12.88,8.14 and 35.89,32.60,all P ＜ 0.05).The positive expression rates of TR2 in rats myocardial tissue of the four groups were 0(0/12),81.8％(9/11),0(0/10) and 100.0％(14/14),respectively.Of which,Se-adequate proteindeficient group and Se-adequate protein-adequate group were significantly higher than Se-deficient protein-deficient group and Se-deficient protein-adequate group (x2 =28.67,18.25 and 35.89,32.60,all P ＜ 0.05).The four groups'results of the overall mean of the relatively value of protein expression of GPX1 in cardiac tissue by Western blotting were 0.87 ± 0.13,1.18 ± 0.13,0.95 ± 0.13 and 1.74 ± 0.23,respectively.Through analysis of variance of factorial design,the effects of Se and protein on protein expression of GPX1 in the heart were statistically significant(F=124.93,43.16,all P＜ 0.05).And there was interaction between them(F=24.10,P＜ 0.05).The four groups'results of the overall mean of the relatively value of protein expression of TR2 in cardiac tissue by Western blotting were 0.63 ± 0.19,0.97 ± 0.24,0.55 ± 0.08 and 1.03 ± 0.31,respectively.Through analysis of variance of factorial design,the effect of Se on expression of TR2 in the heart was statistically significant(F =36.97,P ＜ 0.05).Conclusions Adequate Se and protein diet can increase the levels of GPX1 and TR2 in the heart compared to deficient Se and protein diet,can enhance anti-oxidizing ability,protect the myocardial endothelial cells,reduce degree of myocardial injury,and the combined effects of both are better.

Genetic Variations in TXNRD1 as Potential Predictors of Drug-Induced Liver Injury

PURPOSE: Drug-induced liver injury (DILI) is the most common adverse drug reaction; however, it is not easily predicted. We hypothesize that DILI has a common genetic basis. Based on the findings of previous animal studies on toxic hepatitis, we selected the thioredoxin reductase 1 gene (TXNRD1) as a candidate marker of DILI for this genetic association study. METHODS: Records from 118 patients with DILI were extracted from the database of the Adverse Drug Reaction Research Group in South Korea. Causative drugs included antituberculosis drugs (n=68, 57.6%), antibiotics (n=22, 18.6%), antiepileptic drugs (n=7, 5.9%), non-steroidal anti-inflammatory drugs (n=5, 4.2%), and others (n=16, 13.7%). Seven single nucleotide polymorphisms (SNPs) in TXNRD1 (rs10735393, rs4964287, rs4595619, rs10861201, rs11111997, rs4246270, and rs4246271) were scored in 118 DILI patients and in 120 drug-matched controls without liver injury. RESULTS: No differences were found between the frequencies of any of the 7 SNPs in the cases and controls; however, a significant association was found between a TTA haplotype composed of rs10735393, rs4964287, and rs4595619 and DILI using an allele model (odds ratio, 1.79; 95% confidence interval, 1.18-2.73; P=0.008; Bonferroni corrected P=0.024). CONCLUSIONS: These results suggest that genetic variations in TXNRD1 favor the development of DILI, although a larger confirmative study is needed.

Effects of Hyperoxia on Cytoplasmic Thioredoxin System in Alveolar Type Epithelial Cells of Premature Rats / 华中科技大学学报（医学）（英德文版）

This study investigated the effects of hyperoxia on dynamic changes of thioredoxin-1 (Trx1)and thioredoxin reductase-1 (TrxR1) in alveolar type Ⅱ epithelial cells (AECⅡ) of premature rats.Pregnant Sprague-Dawley rats were sacrificed on day 19 of gestation.AEC Ⅱ were isolated and purified from the lungs of premature rats.When cultured to 80％ confluence,in vitro cells were randomly divided into air group and hyperoxia group.Cells in the hyperoxia group were continuously exposed to 95％ O2/5％ CO2 and those in the air group to 95％ air/5％ CO2.After 12,24 and 48 h,cells in the two groups were harvested to detect their reactive oxygen species (ROS),apoptosis,TrxR1 activity and the expressions of Trx1 and TrxR1 by corresponding protocols,respectively.The results showed that AEC Ⅱ exposed to hyperoxia generated excessive ROS and the apoptosis percentage in the hyperoxia group was increased significantly at each time points as compared with that in the air group (P＜0.001).Moreover,TrxR1 activity was found to be markedly depressed in the hyperoxia group in comparison to that in the air group (P＜0.001).RT-PCR showed the expressions of both Trx1 and TrxR1 mRNA were significantly increased in AEC Ⅱ exposed to hyperoxia for 12 and 24 h (P＜0.01),respectively.At 48 h,the level of Trx1 mRNA as well as that of TrxR1 mRNA in the hyperoxia group was reduced and showed no significant difference from that in the air group (P＞0.05).Western blotting showed the changes of Trx 1 protein expressions in the hyperoxia group paralleled those of Trx1 mRNA expressions revealed by RT-PCR.It was concluded that hyperoxia can up-regulate the protective Trx1/TrxR1 expressed by AEC Ⅱ in a certain period,however,also cause dysfunction of the cytoplasmic thioredoxin system by decreasing TrxR1 activity,which may contribute to the progression of oxidative stress and cell apoptosis and finally result in lung injury.

Preliminary study on the thioredoxin reductase in K562 cells and anti-leukemia effect of BBSKE in vitro / 白血病·淋巴瘤

Objective To explore the activity of thioredoxin reductase (TrxR) in chronic myeloid leukemia cell line K562 and the anti-leukemia effect of BBSKE (a novel inhibitor of TrxR) in vitro. Methods The activity of TrxR on K562 cell lineage and fresh bone marrow cell from healthy adult was analyzed by insulin reduction assay. The inhibition of proliferation was measured by CCK-8 assay. The anti-leukemia effect of BBSKE was detected by laser scanning confocal microscope,agarose gel electrophoresis and flow cytometry with Annexin V -FITC/PI staining. Results TrxR activity of K562 cell lineage was significantly higher than that of normal bone marrow mononuclear cells. The apoptosis of K562 cells could be induced at concentrations of 10 μmol/L BBSKE after treated for 24 hours. The typical DNA ladder bans were observed by agarose gel electrophoresis. The apoptotic rates of K562 cells were (10.28±2.74) %. Application of 10 μmol/L BBSKE for 48 hours could also induce apoptosis of fresh bone marrow cell from chronic myeloid leukemia patients, and the apoptotic rates were (5.70±0.48) %. Conclusion TrxR activity in chronic myeloid leukemia cells was significantly higher than that of normal cells. BBSKE inhibits the TrxR activity and the proliferation of K562 by inducing apoptosis.It might be a potential medication for chronic myeloid leukemia.

Thioredoxin reductase and its inhibitors for cancer therapy / 国际肿瘤学杂志

Thioredoxin reductase(TrxR) is an important component of thiol regulating system and contains a reactive and solvent accessible selenocysteine residue which is located on a flexible C-terminal arm of the protein and can combine various substrates and inhibitors. Many tumor cells have elevated TrxR levels and TrxR has also been shown to play a major role in drug resistance. A great number of effective natural and synthetic TrxR inhibitors are now availably possessing antitumor potential through induction of oxidative stress, cell cycle arrest and apoptosis. Inhibitors of TrxR may thus contribute to a successfully single, combinatory or adjuvant cancer therapy.