Sunlight represents the energy source for photosynthesis and plant growth. When growing in the field, plant photosynthesis has to manage strong fluctuations in light intensities. Regulation based on the thio- redoxin ...Sunlight represents the energy source for photosynthesis and plant growth. When growing in the field, plant photosynthesis has to manage strong fluctuations in light intensities. Regulation based on the thio- redoxin （Trx） system is believed to ensure light-responsive control of photosynthetic reactions in the chlo- roplast. However, direct evidence for a role of this system in regulating dynamic acclimation of photosyn- thesis in fluctuating conditions is largely lacking. In this report we show that the ferredoxin-dependent Trxs ml and m2 as well as the NADPH-dependent NTRC are both indispensable for photosynthetic acclimation in fluctuating light intensities. Arabidopsis mutants with combined deficiency in Trxs ml and m2 show wild- type growth and photosynthesis under constant light condition, while photosynthetic parameters are strongly modified in rapidly alternating high and low light. Two independent trxmlm2 mutants show lower photosynthetic efficiency in high light, but surprisingly significantly higher photosynthetic efficiency in low light. Our data suggest that a main target of Trx ml and m2 is the NADP-malate dehydrogenase involved in export of excess reductive power from the chloroplast. The decreased photosynthetic efficiency in the high-light peaks may thus be explained by a reduced capacity of the trxm lm2 mutants in the rapid light acti-vation of this enzyme. In the ntrc mutant, dynamic responses of non-photochemical quenching of excita- tion energy and plastoquinone reduction state both were strongly attenuated in fluctuating light intensities, leading to a massive decrease in PSII quantum efficiency and a specific decrease in plant growth under these conditions. This is likely due to the decreased ability of the ntrc mutant to control the stromal NADP（H） redox poise. Taken together, our results indicate that NTRC is indispensable in ensuring the full range of dynamic responses of photosynthesis to optimize photosynthesis and maintain growth in fluctu- ating light, while Trxs ml and m2 are indispensable for full activation of photosynthesis in the high-light pe- riods but negatively affect photosynthetic efficiency in the low-light periods of fluctuating light.展开更多
Studies triggered by the discovery of the function of thioredoxin （Trx） in photosynthesis have revealed its role throughout biology. Parallel biochemical and proteomic analyses have led to the identification of its ...Studies triggered by the discovery of the function of thioredoxin （Trx） in photosynthesis have revealed its role throughout biology. Parallel biochemical and proteomic analyses have led to the identification of its numerous puta- tive targets. Recently, to verify the biological significance of these targets, in vivo studies using transformants in which Trx is overexpressed or suppressed are in progress, and the transformants themselves that are being used in such studies show their potential applicative values. Moreover, Trx＇s mitigation of allergenicity for some proteins offers promising prospects in the food industry. Practical studies based on redox regulation, once only on the horizon, are now achieving new dimensions. This short review focuses on the industrial applications of Trx studies, the current situation, and future perspectives. The putative targets obtained by the proteomics approach in comparison with in vivo observations of the transformants are also examined. Applicative studies of glutathione, a counterpart of Trx, are also discussed briefly.展开更多
The expression of the genes encoding the ferredoxin-thioredoxin system including the ferredoxin-thioredoxin reductase （FTR） genes ftrC and ftrV and the four different thioredoxin genes trxA （m-type; sir0623）, trxB...The expression of the genes encoding the ferredoxin-thioredoxin system including the ferredoxin-thioredoxin reductase （FTR） genes ftrC and ftrV and the four different thioredoxin genes trxA （m-type; sir0623）, trxB （x-type; sir1139）, trxC （sll1057） and trxQ （y-type; sir0233） of the cyanobacterium Synechocystis sp. PCC 6803 has been studied according to changes in the photosynthetic conditions. Experiments of light-dark transition indicate that the expression of all these genes except trxQ decreases in the dark in the absence of glucose in the growth medium. The use of two electron transport inhibitors, 3-（3,4-dichlorophenyl）-1,1-dimethylurea （DCMU） and 2,5-dibromo-3-methyl-6-isopropyl-p- benzoquinone （DBMIB）, reveals a differential effect on thioredoxin genes expression being trxC and trxQ almost unaffected, whereas trxA, trxB, and the ftr genes are down-regulated. In the presence of glucose, DCMU does not affect gene expression but DBMIB still does. Analysis of the single TrxB or TrxQ and the double TrxB TrxQ Synechocystis mutant strains reveal different functions for each of these thioredoxins under different growth conditions. Finally, a Synechocystis strain was generated containing a mutated version of TrxB （TrxBC34S）, which was used to identify the potential in-vivo targets of this thioredoxin by a proteomic analysis.展开更多
Thioredoxin is a small ubiquitous protein that is involved in the dithiol-disulfide exchange reaction, byway of two cysteine residues located on the molecule surface. In order to elucidate the role of thioredoxin in C...Thioredoxin is a small ubiquitous protein that is involved in the dithiol-disulfide exchange reaction, byway of two cysteine residues located on the molecule surface. In order to elucidate the role of thioredoxin in Chlorobaculum tepidurn, an anaerobic green sulfur bacterium that uses various inorganic sulfur compounds and H2S as electron donors under strict anaerobic conditions for growth, we applied the thioredoxin affinity chromatography method （Motohashi et al., 2001）. In this study, 37 cytoplasmic proteins were captured as thioredoxin target candidates, including proteins involved in sulfur assimilation. Furthermore, six of the candidate proteins were members of the reductive tricarboxylic acid cycle （pyruvate orthophosphate dikinase, pyruvate flavodoxin/ferredoxin oxidoreductase, ^-oxoglutarate synthase, citrate lyase, citrate synthase, malate dehydrogenase）. The redox sensitivity of three enzymes was then examined： citrate lyase, citrate synthase, and malate dehydrogenase, using their recombinant proteins. Based on the information relating to the target proteins, the significance of thioredoxin as a reductant for the metabolic pathway in the anaerobic photosynthetic bacteria is discussed.展开更多
Selenium(Se),an essential micronutrient among the 15 vital elements required for human physiology,exerts its biological functions primarily through its incorporation into selenoproteins.To date,approximately 25 seleno...Selenium(Se),an essential micronutrient among the 15 vital elements required for human physiology,exerts its biological functions primarily through its incorporation into selenoproteins.To date,approximately 25 selenoproteins have been characterized in mammalian systems,including glutathione peroxidase(GPX),thioredoxin reductase(TrxR),and iodothyronine deiodinases(DIOs),all of which exhibit indispensable physiological functions.展开更多
Capacitation is a series of morphological and metabolic changes necessary for the spermatozoon to achieve fertilizing ability. One of the earlier happenings during mammalian sperm capacitation is the production of rea...Capacitation is a series of morphological and metabolic changes necessary for the spermatozoon to achieve fertilizing ability. One of the earlier happenings during mammalian sperm capacitation is the production of reactive oxygen species （ROS） that will trigger and regulate a series of events including protein phosphorylation, in a time-dependent fashion. The identity of the sperm oxidase responsible for the production of ROS involved in capacitation is still elusive, and several candidates are discussed in this review. Interestingly, ROS-induced ROS formation has been described during human sperm capacitation. Redox signaling during capacitation is associated with changes in thiol groups of proteins located on the plasma membrane and subcellular compartments of the spermatozoon. Both, oxidation of thiols forming disulfide bridges and the increase on thiol content are necessary to regulate different sperm proteins associated with capacitation. Reducing equivalents such as NADH and NADPH are necessary to support capacitation in many species including humans. Lactate dehydrogenase, glucose-6-phospohate dehydrogenase, and isocitrate dehydrogenase are responsible in supplying NAD （P） H for sperm capacitation. Peroxiredoxins （PRDXs） are newly described enzymes with antioxidant properties that can protect mammalian spermatozoa; however, they are also candidates for assuring the regulation of redox signaling required for sperm capacitation. The dysregulation of PRDXs and of enzymes needed for their reactivation such as thioredoxin/thioredoxin reductase system and glutathione-S-transferases impairs sperm motility, capacitation, and promotes DNA damage in spermatozoa leading to male infertility.展开更多
AIM To study the effects of warm ischemia-reperfusion(I/R) injury on hepatic morphology at the ultrastructural level and to analyze the expression of the thioredoxin(TRX)and glutaredoxin(GRX) systems.METHODS Eleven pa...AIM To study the effects of warm ischemia-reperfusion(I/R) injury on hepatic morphology at the ultrastructural level and to analyze the expression of the thioredoxin(TRX)and glutaredoxin(GRX) systems.METHODS Eleven patients undergoing liver resection were subjected to portal triad clamping(PTC). Liver biopsies were collected at three time points; first prior to PTC(baseline), 20 min after PTC(post-ischemia) and 20 min after reperfusion(post-reperfusion). Electron microscopy and morphometry were used to study and quantify ultrastructural changes, respectively. Additionally, gene expression analysis of TRX and GRX isoforms was performed by quantitative PCR. For further validation of redox protein status, immunogold staining was performed for the isoforms GRX1 and TRX1.RESULTS Post-ischemia, a significant loss of the liver sinusoidal endothelial cell(LSEC) lining was observed(P = 0.0003) accompanied by a decrease of hepatocyte microvilli in the space of Disse. Hepatocellular morphology was well preserved apart from the appearance of crystalline mitochondrial inclusions in 7 out of 11 patients. Postreperfusion biopsies had similar features as post-ischemia with the exception of signs of a reactivation of the LSECs. No changes in the expression of redox-regulatory genes could be observed at mR NA level of the isoforms of the TRX family but immunoelectron microscopy indicated a redistribution of TRX1 within the cell.CONCLUSION At the ultrastructural level, the major impact of hepatic warm I/R injury after PTC was borne by the LSECs with detachment and reactivation at ischemia and reperfusion, respectively. Hepatocytes morphology were well preserved. Crystalline inclusions in mitochondria were observed in the hepatocyte after ischemia.展开更多
Ethaselen, an organoselenium compound designed and synthesized in the School of Pharmaceutical Sciences, Peking University, has been entitled to independent intellectual property rights both at home and abroad. As one...Ethaselen, an organoselenium compound designed and synthesized in the School of Pharmaceutical Sciences, Peking University, has been entitled to independent intellectual property rights both at home and abroad. As one of the novel antitumor drugs, ethaselen has been extensively studied in Phase I clinical trial, and its biological target is thioredoxin reductase. In this review, we focus on the ethaselen＇s efficacy and pharmacological actions, including antitumor effects both in vitro and in vivo, and immunologic functions. These research findings not only provide the theoretical basis for the anticancer study of ethaselen, but also guide the clinical trial of ethaselen.展开更多
We investigated the redox status of H22 hepatocellular carcinoma xenografts treated with various doses of ethaselen, a novel anticancer drug targeting thioredoxin reductase （TrxR）. The concentrations of low molecula...We investigated the redox status of H22 hepatocellular carcinoma xenografts treated with various doses of ethaselen, a novel anticancer drug targeting thioredoxin reductase （TrxR）. The concentrations of low molecular weight antioxidant g!utathione （GSH） and malondialdehyde （MDA）, a product of lipid peroxidation, as well as the activities of important antioxidant enzymes were measured for elucidating the redox status of H22 tumor tissues. We found that the decreased GSH level, decreased thioredoxin reductase and superoxide dismutase （SOD） activities as well as increased MDA content were closely related to the tumor growth inhibition and ethaselen doses. Glutathione peroxidase （GPx） and glutathinne reductase （GR） activities are also affected by ethaselen treatment. However, the catalase （CAT） activity remains unchanged. Finally, we studied the relationship of tumor growth inhibition caused by ethaselen with these redox factors. This study showed that ethaselen could elevate the oxidative stress to suppress the H22 tumor growth in mice model.展开更多
Reactive oxygen species (ROS) are produced under oxidative stress, such as high oxygen concentration and during the metabolic consumption of oxygen molecules. Male reproductive tissues appear to be continuously expose...Reactive oxygen species (ROS) are produced under oxidative stress, such as high oxygen concentration and during the metabolic consumption of oxygen molecules. Male reproductive tissues appear to be continuously exposed to ROS produced by active metabolism. In addition, spermatozoa must pass through a high oxygen environment during the mating process. Thus, to maintain viable reproductive ability, a protective mechanism against oxidative stress is of importance. Here, we overview our current understanding of the cooperative function of antioxidative and redox systems that are involved in male fertility. Superoxide dismutase and glutathione peroxidase are major enzymes that scavenge harmful ROS in male reproductive organs. In turn, glutathione and thioredoxin systems constitute the main redox systems that repair oxidized and damaged molecules and also play a role in regulating a variety of cellular functions. While glutathione functions as an antioxidant by donating electrons to glutathione peroxidase and thioredoxin donates electrons to peroxiredoxin as a counterpart of glutathione peroxidase. In addition, aldo-keto reductases, which detoxify carbonyl compounds produced by oxidative stress, are present at high levels in the epithelia of the genital tract and Sertoli cells of the testis. Since these systems are involved in cross-talk, a comprehensive understanding will be required to maintain the physiological functions of male reproductive system.展开更多
AIM:To investigate the effectiveness of antioxidant compounds in modulating mitochondrial oxidative alterations and lipids accumulation in fatty hepatocytes.METHODS:Silybin-phospholipid complex containing vitamin E(Re...AIM:To investigate the effectiveness of antioxidant compounds in modulating mitochondrial oxidative alterations and lipids accumulation in fatty hepatocytes.METHODS:Silybin-phospholipid complex containing vitamin E(Realsil) was daily administered by gavage(one pouch diluted in 3 mL of water and containing 15 mg vitamin E and 47 mg silybin complexed with phospholipids) to rats fed a choline-deprived(CD) or a high fat diet [20% fat,containing 71% total calories as fat,11% as carbohydrate,and 18% as protein,high fat diet(HFD)] for 30 d and 60 d,respectively.The control group was fed a normal semi-purified diet containing adequate levels of choline(35% total calories as fat,47% as carbohydrate,and 18% as protein).Circulating and hepatic redox active and nitrogen regulating molecules(thioredoxin,glutathione,glutathione peroxidase),NO metabolites(nitrosothiols,nitrotyrosine),lipid peroxides [malondialdehyde-thiobarbituric(MDA-TBA)],and pro-inflammatory keratins(K-18) were measured on days 0,7,14,30,and 60.Mitochondrial respiratory chain proteins and the extent of hepatic fatty infiltration were evaluated.RESULTS:Both diet regimens produced liver steatosis(50% and 25% of liver slices with CD and HFD,respectively) with no signs of necro-inflammation:fat infiltration ranged from large droplets at day 14 to disseminated and confluent vacuoles resulting in microvesicular steatosis at day 30(CD) and day 60(HFD).In plasma,thioredoxin and nitrosothiols were not significantly changed,while MDA-TBA,nitrotyrosine(from 6 ± 1 nmol/L to 14 ± 3 nmol/L day 30 CD,P < 0.001,and 12 ± 2 nmol/L day 60 HFD,P < 0.001),and K-18(from 198 ± 20 to 289 ± 21 U/L day 30 CD,P < 0.001,and 242 ± 23 U/L day 60 HFD,P < 0.001) levels increased significantly with ongoing steatosis.In the liver,glutathione was decreased(from 34.0 ± 1.3 to 25.3 ± 1.2 nmol/mg prot day 30 CD,P < 0.001,and 22.4 ± 2.4 nmol/mg prot day 60 HFD,P < 0.001),while thioredoxin and glutathione peroxidase were initially increased and then decreased.Nitrosothiols were constantly increased.MDA-TBA levels were five-fold increased from 9.1 ± 1.2 nmol/g to 75.6 ± 5.4 nmol/g on day 30,P < 0.001(CD) and doubled with HFD on day 60.Realsil administration significantly lowered the extent of fat infiltration,maintained liver glutathione levels during the first half period,and halved its decrease during the second half.Also,Realsil modulated thioredoxin changes and the production of NO derivatives and significantly lowered MDA-TBA levels both in liver(from 73.6 ± 5.4 to 57.2 ± 6.3 nmol/g day 30 CD,P < 0.01 and from 27.3 ± 2.1 nmol/g to 20.5 ± 2.2 nmol/g day 60 HFD,P < 0.01) and in plasma.Changes in mitochondrial respiratory complexes were also attenuated by Realsil in HFD rats with a major protective effect on Complex Ⅱ subunit CII-30.CONCLUSION:Realsil administration effectively contrasts hepatocyte fat deposition,NO derivatives formation,and mitochondrial alterations,allowing the liver to maintain a better glutathione and thioredoxin antioxidant activity.展开更多
Two heterologous expression systems using thioredoxin (trxA) as a gene fusion part in Escherichia coli were developed to produce recombinant pediocin PA-1.Pediocin PA-1 structural gene pedA was isolated from Pediococc...Two heterologous expression systems using thioredoxin (trxA) as a gene fusion part in Escherichia coli were developed to produce recombinant pediocin PA-1.Pediocin PA-1 structural gene pedA was isolated from Pediococcus acidilactici PA003 by the method of polymerase chain reaction (PCR),then cloned into vector pET32a(+),and expressed as thioredoxin-PedA fusion protein in the host strain E.coli BL21 (DE3).The fusion protein was in the form of inclusion body and was refolded before purification by nickel-iminodiacetic acid (Ni-IDA) agarose resin column.Biological activity of recombinant pediocin PA-1 was analyzed after cleavage of the fusion protein by enterokinase.Agar diffusion test revealed that 512-arbitrary unit (AU) recombinant pediocin PA-1 was obtained from 1 ml culture medium of E.coli (pPA003PED1) using Listeria monocytogenes as the indicator strain.Thioredoxin-PedA fusion gene was further cloned into pET20b(+).Thioredoxin-PedA fusion protein was detected in both the periplasmic and cytoplasmic spaces.The recombinant pediocin PA-1 from the soluble fraction attained 384 AU from 1 ml culture medium of E.coli (pPA003PED2).Therefore,biologically active pediocin PA-1 could be obtained by these two hybrid gene expression methods.展开更多
Primary biliary cirrhosis is a multifactor autoimmune disease characterized by hepatic and systemic manifestations,with immune system dysregulation and abnormalities in the hepatic metabolism of bile salts,lipids,and ...Primary biliary cirrhosis is a multifactor autoimmune disease characterized by hepatic and systemic manifestations,with immune system dysregulation and abnormalities in the hepatic metabolism of bile salts,lipids,and nutrients,as well as destruction of membrane lipids and mitochondrial dysfunction.Both oxidative and nitrosative stress are associated with ongoing manifestations of the disease.In particular,abnormalities in nitric oxide metabolism and thiol oxidation already occur at early stages,thus leading to the hypothesis that these biochemical events play a pathogenic role in primary biliary cirrhosis.Moreover,the association of these metabolic abnormalities with the progression of the disease may indicate some biochemical parameters as early diagnostic markers of disease evolution,and may open up the potential for pharmacological intervention to inhibit intra-and extra-cellular stress events for resuming hepatocellular functions.The following paragraphs summarize the current knowledge by outlining molecular mechanisms of the disease related to these stress events.展开更多
Tissue and systemic inflammation have been the main culprit behind the cellular response to multiple insults and maintaining homeostasis.Obesity is an independent disease state that has been reported as a common risk ...Tissue and systemic inflammation have been the main culprit behind the cellular response to multiple insults and maintaining homeostasis.Obesity is an independent disease state that has been reported as a common risk factor for multiple metabolic and microvascular diseases including nonalcoholic fatty liver disease(NAFLD),retinopathy,critical limb ischemia,and impaired angiogenesis.Sterile inflammation driven by high-fat diet,increased formation of reactive oxygen species,alteration of intracellular calcium level and associated release of inflammatory mediators,are the main common underlying forces in the pathophysiology of NAFLD,ischemic retinopathy,stroke,and aging brain.This work aims to examine the contribution of the pro-oxidative and pro-inflammatory thioredoxin interacting protein(TXNIP)to the expression and activation of NLRP3-inflammasome resulting in initiation or exacerbation of sterile inflammation in these disease states.Finally,the potential for TXNIP as a therapeutic target and whether TXNIP expression can be modulated using natural antioxidants or repurposing other drugs will be discussed.展开更多
AIM:To evaluate the potential of thioredoxin (TXN) and thioredoxin-interacting protein (TXNIP) expression as biomarkers for predicting gastric cancer recurrence. METHODS:TXN and TXNIP expression levels were acquired f...AIM:To evaluate the potential of thioredoxin (TXN) and thioredoxin-interacting protein (TXNIP) expression as biomarkers for predicting gastric cancer recurrence. METHODS:TXN and TXNIP expression levels were acquired from gene expression microarray data for 65 human gastric cancer tissues. We determined whether each gene expression level was associated with cancer recurrence and investigated the relationship between the two genes. For validation, the expression levels of TXN and TXNIP were measured by quantitative real- time reverse transcription polymerase chain reaction in 68 independent stage Ⅲ gastric cancer patients. The correlation between gene expression and cancer prognosis was evaluated. Immunohistochemical staining was performed to investigate the protein expression levels of TXN and TXNIP and to characterize the expression patterns of each protein. RESULTS:TXN was a prognosis-related gene (P = 0.009), whereas TXNIP, a TXN inhibitor, demonstrated a negative correlation with TXN in the gene expression microarray data. In the 68 stage Ⅲ patients, the expression levels of both TXN and TXNIP had a statistically significant effect on recurrence-free survival (RFS, P = 0.008 and P = 0.036, respectively). The low TXN and high TXNIP expression group exhibited a better prognosis than the other groups, and the high TXN and low TXNIP expression group exhibited a poorer prognosis (P < 0.001 for RFS and P = 0.001 for overall survival). More than half of the patients in the simulta-neously high TXN and low TXNIP expression group ex- perienced a recurrence within 1 year after curative surgery, and the 5-year survival rate of the patients in this group was 29%, compared with 89% in the low TXN and high TXNIP expression group. The TXN protein was overexpressed in 65% of the gastric cancer tissues, whereas the TXNIP protein was underexpressed in 85% of the cancer cells. In a correlation analysis, TXN and TXNIP were highly correlated with many oncogenes and tumor suppressors as well as with genes related to energy, protein synthesis and autophagy. CONCLUSION:TXN and TXNIP are promising prognostic markers for gastric cancer, and performing personalized adjuvant treatment based on TXN and TXNIP expression levels would be an effective practice in the treatment of gastric cancer.展开更多
LHCII is a crucial light-harvesting pigment/protein complex in photosystem II (PSII) supercomplex. It also participates in the light energy redistribution between photosystems and in the photoprotection via its revers...LHCII is a crucial light-harvesting pigment/protein complex in photosystem II (PSII) supercomplex. It also participates in the light energy redistribution between photosystems and in the photoprotection via its reversible dissociation with PSII and PSI (photosystem I). This reversible detachment of LHCII is regulated by phosphorylation of its own and PSII core protein. Under low light conditions, LHCII is phosphorylated and dissociated with PSII core protein complex and combined with PSI, which balances the excitation energy between PSII and PSI;Under high light environment, the phosphorylation of PSII core proteins makes LHCII detach from PSII. The dissociated LHCII presents in a free state, which involves in the thermal dissipation of excess excitation energy. During photodamage, dual phosphorylations of both PSII core proteins and LHCII complexes occur. The phosphorylation of D1 is conductive to the disintegration of photodamaged PSII and the cycle of repair. In this circumstance, the phosphorylation of LHCII is induced by reactive oxygen species (ROS) and then the phosphorylated LHCII migrates to PSI, into the repair cycle of damaged PSII. The ferredoxin (Fdr) and thioredoxin (Tdr) system may play a possible central role in the phosphorylation regulation on LHCII dissociation.展开更多
Ribonucleotide reductase(RNR), the rate-limitingenzyme in DNA synthesis, catalyzes reduction of thedifferent ribonucleotides to their corresponding deoxyri-bonucleotides. The crucial role of RNR in DNA synthesishas ma...Ribonucleotide reductase(RNR), the rate-limitingenzyme in DNA synthesis, catalyzes reduction of thedifferent ribonucleotides to their corresponding deoxyri-bonucleotides. The crucial role of RNR in DNA synthesishas made it an important target for the development ofantiviral and anticancer drugs. Taking account of the re-cent developments in this field of research, this reviewfocuses on the role of thioredoxin and glutaredoxin sys-tems in the redox reactions of the RNR catalysis.展开更多
文摘Sunlight represents the energy source for photosynthesis and plant growth. When growing in the field, plant photosynthesis has to manage strong fluctuations in light intensities. Regulation based on the thio- redoxin （Trx） system is believed to ensure light-responsive control of photosynthetic reactions in the chlo- roplast. However, direct evidence for a role of this system in regulating dynamic acclimation of photosyn- thesis in fluctuating conditions is largely lacking. In this report we show that the ferredoxin-dependent Trxs ml and m2 as well as the NADPH-dependent NTRC are both indispensable for photosynthetic acclimation in fluctuating light intensities. Arabidopsis mutants with combined deficiency in Trxs ml and m2 show wild- type growth and photosynthesis under constant light condition, while photosynthetic parameters are strongly modified in rapidly alternating high and low light. Two independent trxmlm2 mutants show lower photosynthetic efficiency in high light, but surprisingly significantly higher photosynthetic efficiency in low light. Our data suggest that a main target of Trx ml and m2 is the NADP-malate dehydrogenase involved in export of excess reductive power from the chloroplast. The decreased photosynthetic efficiency in the high-light peaks may thus be explained by a reduced capacity of the trxm lm2 mutants in the rapid light acti-vation of this enzyme. In the ntrc mutant, dynamic responses of non-photochemical quenching of excita- tion energy and plastoquinone reduction state both were strongly attenuated in fluctuating light intensities, leading to a massive decrease in PSII quantum efficiency and a specific decrease in plant growth under these conditions. This is likely due to the decreased ability of the ntrc mutant to control the stromal NADP（H） redox poise. Taken together, our results indicate that NTRC is indispensable in ensuring the full range of dynamic responses of photosynthesis to optimize photosynthesis and maintain growth in fluctu- ating light, while Trxs ml and m2 are indispensable for full activation of photosynthesis in the high-light pe- riods but negatively affect photosynthetic efficiency in the low-light periods of fluctuating light.
文摘Studies triggered by the discovery of the function of thioredoxin （Trx） in photosynthesis have revealed its role throughout biology. Parallel biochemical and proteomic analyses have led to the identification of its numerous puta- tive targets. Recently, to verify the biological significance of these targets, in vivo studies using transformants in which Trx is overexpressed or suppressed are in progress, and the transformants themselves that are being used in such studies show their potential applicative values. Moreover, Trx＇s mitigation of allergenicity for some proteins offers promising prospects in the food industry. Practical studies based on redox regulation, once only on the horizon, are now achieving new dimensions. This short review focuses on the industrial applications of Trx studies, the current situation, and future perspectives. The putative targets obtained by the proteomics approach in comparison with in vivo observations of the transformants are also examined. Applicative studies of glutathione, a counterpart of Trx, are also discussed briefly.
文摘The expression of the genes encoding the ferredoxin-thioredoxin system including the ferredoxin-thioredoxin reductase （FTR） genes ftrC and ftrV and the four different thioredoxin genes trxA （m-type; sir0623）, trxB （x-type; sir1139）, trxC （sll1057） and trxQ （y-type; sir0233） of the cyanobacterium Synechocystis sp. PCC 6803 has been studied according to changes in the photosynthetic conditions. Experiments of light-dark transition indicate that the expression of all these genes except trxQ decreases in the dark in the absence of glucose in the growth medium. The use of two electron transport inhibitors, 3-（3,4-dichlorophenyl）-1,1-dimethylurea （DCMU） and 2,5-dibromo-3-methyl-6-isopropyl-p- benzoquinone （DBMIB）, reveals a differential effect on thioredoxin genes expression being trxC and trxQ almost unaffected, whereas trxA, trxB, and the ftr genes are down-regulated. In the presence of glucose, DCMU does not affect gene expression but DBMIB still does. Analysis of the single TrxB or TrxQ and the double TrxB TrxQ Synechocystis mutant strains reveal different functions for each of these thioredoxins under different growth conditions. Finally, a Synechocystis strain was generated containing a mutated version of TrxB （TrxBC34S）, which was used to identify the potential in-vivo targets of this thioredoxin by a proteomic analysis.
文摘Thioredoxin is a small ubiquitous protein that is involved in the dithiol-disulfide exchange reaction, byway of two cysteine residues located on the molecule surface. In order to elucidate the role of thioredoxin in Chlorobaculum tepidurn, an anaerobic green sulfur bacterium that uses various inorganic sulfur compounds and H2S as electron donors under strict anaerobic conditions for growth, we applied the thioredoxin affinity chromatography method （Motohashi et al., 2001）. In this study, 37 cytoplasmic proteins were captured as thioredoxin target candidates, including proteins involved in sulfur assimilation. Furthermore, six of the candidate proteins were members of the reductive tricarboxylic acid cycle （pyruvate orthophosphate dikinase, pyruvate flavodoxin/ferredoxin oxidoreductase, ^-oxoglutarate synthase, citrate lyase, citrate synthase, malate dehydrogenase）. The redox sensitivity of three enzymes was then examined： citrate lyase, citrate synthase, and malate dehydrogenase, using their recombinant proteins. Based on the information relating to the target proteins, the significance of thioredoxin as a reductant for the metabolic pathway in the anaerobic photosynthetic bacteria is discussed.
基金Financial support from the Science and Technology Innovation Program of Hunan Province(No.2022RC4044)。
文摘Selenium(Se),an essential micronutrient among the 15 vital elements required for human physiology,exerts its biological functions primarily through its incorporation into selenoproteins.To date,approximately 25 selenoproteins have been characterized in mammalian systems,including glutathione peroxidase(GPX),thioredoxin reductase(TrxR),and iodothyronine deiodinases(DIOs),all of which exhibit indispensable physiological functions.
文摘Capacitation is a series of morphological and metabolic changes necessary for the spermatozoon to achieve fertilizing ability. One of the earlier happenings during mammalian sperm capacitation is the production of reactive oxygen species （ROS） that will trigger and regulate a series of events including protein phosphorylation, in a time-dependent fashion. The identity of the sperm oxidase responsible for the production of ROS involved in capacitation is still elusive, and several candidates are discussed in this review. Interestingly, ROS-induced ROS formation has been described during human sperm capacitation. Redox signaling during capacitation is associated with changes in thiol groups of proteins located on the plasma membrane and subcellular compartments of the spermatozoon. Both, oxidation of thiols forming disulfide bridges and the increase on thiol content are necessary to regulate different sperm proteins associated with capacitation. Reducing equivalents such as NADH and NADPH are necessary to support capacitation in many species including humans. Lactate dehydrogenase, glucose-6-phospohate dehydrogenase, and isocitrate dehydrogenase are responsible in supplying NAD （P） H for sperm capacitation. Peroxiredoxins （PRDXs） are newly described enzymes with antioxidant properties that can protect mammalian spermatozoa; however, they are also candidates for assuring the regulation of redox signaling required for sperm capacitation. The dysregulation of PRDXs and of enzymes needed for their reactivation such as thioredoxin/thioredoxin reductase system and glutathione-S-transferases impairs sperm motility, capacitation, and promotes DNA damage in spermatozoa leading to male infertility.
基金Supported by Swedish Cancer society(Cancerfonden)the Swedish Cancer and Allergy fund(Cancer-och Allergifonden)
文摘AIM To study the effects of warm ischemia-reperfusion(I/R) injury on hepatic morphology at the ultrastructural level and to analyze the expression of the thioredoxin(TRX)and glutaredoxin(GRX) systems.METHODS Eleven patients undergoing liver resection were subjected to portal triad clamping(PTC). Liver biopsies were collected at three time points; first prior to PTC(baseline), 20 min after PTC(post-ischemia) and 20 min after reperfusion(post-reperfusion). Electron microscopy and morphometry were used to study and quantify ultrastructural changes, respectively. Additionally, gene expression analysis of TRX and GRX isoforms was performed by quantitative PCR. For further validation of redox protein status, immunogold staining was performed for the isoforms GRX1 and TRX1.RESULTS Post-ischemia, a significant loss of the liver sinusoidal endothelial cell(LSEC) lining was observed(P = 0.0003) accompanied by a decrease of hepatocyte microvilli in the space of Disse. Hepatocellular morphology was well preserved apart from the appearance of crystalline mitochondrial inclusions in 7 out of 11 patients. Postreperfusion biopsies had similar features as post-ischemia with the exception of signs of a reactivation of the LSECs. No changes in the expression of redox-regulatory genes could be observed at mR NA level of the isoforms of the TRX family but immunoelectron microscopy indicated a redistribution of TRX1 within the cell.CONCLUSION At the ultrastructural level, the major impact of hepatic warm I/R injury after PTC was borne by the LSECs with detachment and reactivation at ischemia and reperfusion, respectively. Hepatocytes morphology were well preserved. Crystalline inclusions in mitochondria were observed in the hepatocyte after ischemia.
基金National Natural Science Foundation of China(Grant No.30472036)
文摘Ethaselen, an organoselenium compound designed and synthesized in the School of Pharmaceutical Sciences, Peking University, has been entitled to independent intellectual property rights both at home and abroad. As one of the novel antitumor drugs, ethaselen has been extensively studied in Phase I clinical trial, and its biological target is thioredoxin reductase. In this review, we focus on the ethaselen＇s efficacy and pharmacological actions, including antitumor effects both in vitro and in vivo, and immunologic functions. These research findings not only provide the theoretical basis for the anticancer study of ethaselen, but also guide the clinical trial of ethaselen.
基金National Natural Science Foundation of China (Grant No.30472036).
文摘We investigated the redox status of H22 hepatocellular carcinoma xenografts treated with various doses of ethaselen, a novel anticancer drug targeting thioredoxin reductase （TrxR）. The concentrations of low molecular weight antioxidant g!utathione （GSH） and malondialdehyde （MDA）, a product of lipid peroxidation, as well as the activities of important antioxidant enzymes were measured for elucidating the redox status of H22 tumor tissues. We found that the decreased GSH level, decreased thioredoxin reductase and superoxide dismutase （SOD） activities as well as increased MDA content were closely related to the tumor growth inhibition and ethaselen doses. Glutathione peroxidase （GPx） and glutathinne reductase （GR） activities are also affected by ethaselen treatment. However, the catalase （CAT） activity remains unchanged. Finally, we studied the relationship of tumor growth inhibition caused by ethaselen with these redox factors. This study showed that ethaselen could elevate the oxidative stress to suppress the H22 tumor growth in mice model.
文摘Reactive oxygen species (ROS) are produced under oxidative stress, such as high oxygen concentration and during the metabolic consumption of oxygen molecules. Male reproductive tissues appear to be continuously exposed to ROS produced by active metabolism. In addition, spermatozoa must pass through a high oxygen environment during the mating process. Thus, to maintain viable reproductive ability, a protective mechanism against oxidative stress is of importance. Here, we overview our current understanding of the cooperative function of antioxidative and redox systems that are involved in male fertility. Superoxide dismutase and glutathione peroxidase are major enzymes that scavenge harmful ROS in male reproductive organs. In turn, glutathione and thioredoxin systems constitute the main redox systems that repair oxidized and damaged molecules and also play a role in regulating a variety of cellular functions. While glutathione functions as an antioxidant by donating electrons to glutathione peroxidase and thioredoxin donates electrons to peroxiredoxin as a counterpart of glutathione peroxidase. In addition, aldo-keto reductases, which detoxify carbonyl compounds produced by oxidative stress, are present at high levels in the epithelia of the genital tract and Sertoli cells of the testis. Since these systems are involved in cross-talk, a comprehensive understanding will be required to maintain the physiological functions of male reproductive system.
基金Supported by Grants from MIUR(Ministero Università e Ricerca Scientifica COFIN2006)"Fondi Ateneo Ricerca Scientifica 2005/2006" from the University of Bari,Italy
文摘AIM:To investigate the effectiveness of antioxidant compounds in modulating mitochondrial oxidative alterations and lipids accumulation in fatty hepatocytes.METHODS:Silybin-phospholipid complex containing vitamin E(Realsil) was daily administered by gavage(one pouch diluted in 3 mL of water and containing 15 mg vitamin E and 47 mg silybin complexed with phospholipids) to rats fed a choline-deprived(CD) or a high fat diet [20% fat,containing 71% total calories as fat,11% as carbohydrate,and 18% as protein,high fat diet(HFD)] for 30 d and 60 d,respectively.The control group was fed a normal semi-purified diet containing adequate levels of choline(35% total calories as fat,47% as carbohydrate,and 18% as protein).Circulating and hepatic redox active and nitrogen regulating molecules(thioredoxin,glutathione,glutathione peroxidase),NO metabolites(nitrosothiols,nitrotyrosine),lipid peroxides [malondialdehyde-thiobarbituric(MDA-TBA)],and pro-inflammatory keratins(K-18) were measured on days 0,7,14,30,and 60.Mitochondrial respiratory chain proteins and the extent of hepatic fatty infiltration were evaluated.RESULTS:Both diet regimens produced liver steatosis(50% and 25% of liver slices with CD and HFD,respectively) with no signs of necro-inflammation:fat infiltration ranged from large droplets at day 14 to disseminated and confluent vacuoles resulting in microvesicular steatosis at day 30(CD) and day 60(HFD).In plasma,thioredoxin and nitrosothiols were not significantly changed,while MDA-TBA,nitrotyrosine(from 6 ± 1 nmol/L to 14 ± 3 nmol/L day 30 CD,P < 0.001,and 12 ± 2 nmol/L day 60 HFD,P < 0.001),and K-18(from 198 ± 20 to 289 ± 21 U/L day 30 CD,P < 0.001,and 242 ± 23 U/L day 60 HFD,P < 0.001) levels increased significantly with ongoing steatosis.In the liver,glutathione was decreased(from 34.0 ± 1.3 to 25.3 ± 1.2 nmol/mg prot day 30 CD,P < 0.001,and 22.4 ± 2.4 nmol/mg prot day 60 HFD,P < 0.001),while thioredoxin and glutathione peroxidase were initially increased and then decreased.Nitrosothiols were constantly increased.MDA-TBA levels were five-fold increased from 9.1 ± 1.2 nmol/g to 75.6 ± 5.4 nmol/g on day 30,P < 0.001(CD) and doubled with HFD on day 60.Realsil administration significantly lowered the extent of fat infiltration,maintained liver glutathione levels during the first half period,and halved its decrease during the second half.Also,Realsil modulated thioredoxin changes and the production of NO derivatives and significantly lowered MDA-TBA levels both in liver(from 73.6 ± 5.4 to 57.2 ± 6.3 nmol/g day 30 CD,P < 0.01 and from 27.3 ± 2.1 nmol/g to 20.5 ± 2.2 nmol/g day 60 HFD,P < 0.01) and in plasma.Changes in mitochondrial respiratory complexes were also attenuated by Realsil in HFD rats with a major protective effect on Complex Ⅱ subunit CII-30.CONCLUSION:Realsil administration effectively contrasts hepatocyte fat deposition,NO derivatives formation,and mitochondrial alterations,allowing the liver to maintain a better glutathione and thioredoxin antioxidant activity.
基金Project supported by the National Natural Science Foundation of China (No.30571378)the Tianjin Natural Science Foundation (No.08JCZDJC22500),China
文摘Two heterologous expression systems using thioredoxin (trxA) as a gene fusion part in Escherichia coli were developed to produce recombinant pediocin PA-1.Pediocin PA-1 structural gene pedA was isolated from Pediococcus acidilactici PA003 by the method of polymerase chain reaction (PCR),then cloned into vector pET32a(+),and expressed as thioredoxin-PedA fusion protein in the host strain E.coli BL21 (DE3).The fusion protein was in the form of inclusion body and was refolded before purification by nickel-iminodiacetic acid (Ni-IDA) agarose resin column.Biological activity of recombinant pediocin PA-1 was analyzed after cleavage of the fusion protein by enterokinase.Agar diffusion test revealed that 512-arbitrary unit (AU) recombinant pediocin PA-1 was obtained from 1 ml culture medium of E.coli (pPA003PED1) using Listeria monocytogenes as the indicator strain.Thioredoxin-PedA fusion gene was further cloned into pET20b(+).Thioredoxin-PedA fusion protein was detected in both the periplasmic and cytoplasmic spaces.The recombinant pediocin PA-1 from the soluble fraction attained 384 AU from 1 ml culture medium of E.coli (pPA003PED2).Therefore,biologically active pediocin PA-1 could be obtained by these two hybrid gene expression methods.
文摘Primary biliary cirrhosis is a multifactor autoimmune disease characterized by hepatic and systemic manifestations,with immune system dysregulation and abnormalities in the hepatic metabolism of bile salts,lipids,and nutrients,as well as destruction of membrane lipids and mitochondrial dysfunction.Both oxidative and nitrosative stress are associated with ongoing manifestations of the disease.In particular,abnormalities in nitric oxide metabolism and thiol oxidation already occur at early stages,thus leading to the hypothesis that these biochemical events play a pathogenic role in primary biliary cirrhosis.Moreover,the association of these metabolic abnormalities with the progression of the disease may indicate some biochemical parameters as early diagnostic markers of disease evolution,and may open up the potential for pharmacological intervention to inhibit intra-and extra-cellular stress events for resuming hepatocellular functions.The following paragraphs summarize the current knowledge by outlining molecular mechanisms of the disease related to these stress events.
文摘Tissue and systemic inflammation have been the main culprit behind the cellular response to multiple insults and maintaining homeostasis.Obesity is an independent disease state that has been reported as a common risk factor for multiple metabolic and microvascular diseases including nonalcoholic fatty liver disease(NAFLD),retinopathy,critical limb ischemia,and impaired angiogenesis.Sterile inflammation driven by high-fat diet,increased formation of reactive oxygen species,alteration of intracellular calcium level and associated release of inflammatory mediators,are the main common underlying forces in the pathophysiology of NAFLD,ischemic retinopathy,stroke,and aging brain.This work aims to examine the contribution of the pro-oxidative and pro-inflammatory thioredoxin interacting protein(TXNIP)to the expression and activation of NLRP3-inflammasome resulting in initiation or exacerbation of sterile inflammation in these disease states.Finally,the potential for TXNIP as a therapeutic target and whether TXNIP expression can be modulated using natural antioxidants or repurposing other drugs will be discussed.
基金Supported by The Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education, Science and Technology, No. 2010-0024248A Faculty Research Grant from Yonsei University College of Medicine for 2011, No. 6-2011-0113, 6-2011-0146
文摘AIM:To evaluate the potential of thioredoxin (TXN) and thioredoxin-interacting protein (TXNIP) expression as biomarkers for predicting gastric cancer recurrence. METHODS:TXN and TXNIP expression levels were acquired from gene expression microarray data for 65 human gastric cancer tissues. We determined whether each gene expression level was associated with cancer recurrence and investigated the relationship between the two genes. For validation, the expression levels of TXN and TXNIP were measured by quantitative real- time reverse transcription polymerase chain reaction in 68 independent stage Ⅲ gastric cancer patients. The correlation between gene expression and cancer prognosis was evaluated. Immunohistochemical staining was performed to investigate the protein expression levels of TXN and TXNIP and to characterize the expression patterns of each protein. RESULTS:TXN was a prognosis-related gene (P = 0.009), whereas TXNIP, a TXN inhibitor, demonstrated a negative correlation with TXN in the gene expression microarray data. In the 68 stage Ⅲ patients, the expression levels of both TXN and TXNIP had a statistically significant effect on recurrence-free survival (RFS, P = 0.008 and P = 0.036, respectively). The low TXN and high TXNIP expression group exhibited a better prognosis than the other groups, and the high TXN and low TXNIP expression group exhibited a poorer prognosis (P < 0.001 for RFS and P = 0.001 for overall survival). More than half of the patients in the simulta-neously high TXN and low TXNIP expression group ex- perienced a recurrence within 1 year after curative surgery, and the 5-year survival rate of the patients in this group was 29%, compared with 89% in the low TXN and high TXNIP expression group. The TXN protein was overexpressed in 65% of the gastric cancer tissues, whereas the TXNIP protein was underexpressed in 85% of the cancer cells. In a correlation analysis, TXN and TXNIP were highly correlated with many oncogenes and tumor suppressors as well as with genes related to energy, protein synthesis and autophagy. CONCLUSION:TXN and TXNIP are promising prognostic markers for gastric cancer, and performing personalized adjuvant treatment based on TXN and TXNIP expression levels would be an effective practice in the treatment of gastric cancer.
文摘LHCII is a crucial light-harvesting pigment/protein complex in photosystem II (PSII) supercomplex. It also participates in the light energy redistribution between photosystems and in the photoprotection via its reversible dissociation with PSII and PSI (photosystem I). This reversible detachment of LHCII is regulated by phosphorylation of its own and PSII core protein. Under low light conditions, LHCII is phosphorylated and dissociated with PSII core protein complex and combined with PSI, which balances the excitation energy between PSII and PSI;Under high light environment, the phosphorylation of PSII core proteins makes LHCII detach from PSII. The dissociated LHCII presents in a free state, which involves in the thermal dissipation of excess excitation energy. During photodamage, dual phosphorylations of both PSII core proteins and LHCII complexes occur. The phosphorylation of D1 is conductive to the disintegration of photodamaged PSII and the cycle of repair. In this circumstance, the phosphorylation of LHCII is induced by reactive oxygen species (ROS) and then the phosphorylated LHCII migrates to PSI, into the repair cycle of damaged PSII. The ferredoxin (Fdr) and thioredoxin (Tdr) system may play a possible central role in the phosphorylation regulation on LHCII dissociation.
基金Supported by The Swedish Research Council Medicine,No.3529The Swedish Cancer Society,No.961The Wallenberg Foundation
文摘Ribonucleotide reductase(RNR), the rate-limitingenzyme in DNA synthesis, catalyzes reduction of thedifferent ribonucleotides to their corresponding deoxyri-bonucleotides. The crucial role of RNR in DNA synthesishas made it an important target for the development ofantiviral and anticancer drugs. Taking account of the re-cent developments in this field of research, this reviewfocuses on the role of thioredoxin and glutaredoxin sys-tems in the redox reactions of the RNR catalysis.
