Cellular thiols and redox-regulated signal transduction

A simple Ag-MoS2 hybrid nanozyme-based sensor array for colorimetric identification of biothiols and cancer cells

The intracellular levels of biothiols are associated with various diseases including cancer, and biothiols are regarded as tumor biomarker. Due to the similarity of the molecular structure of biothiols, the development of simple, rapid, efficient, and sensitive colorimetric sensor arrays holds great promise for clinical cancer diagnosis. Here, we developed a simple Ag-MoS2 hybrid nanozyme-based sensor array for colorimetric identification of biothiols and cancer cells. The novel Ag-MoS2 nanoprobe was synthesized in a simple and efficient way through the in situ self-reduction reaction between MoS2 and noble metal precursor. Benefiting from to the formation of heterogeneous metal structures, the peroxidase (POD)-like catalytic activity of the synthesized Ag-MoS2 hybrid nanocomposites is significantly enhanced compared to MoS2 alone. Moreover, the catalytic activity of Ag-MoS2 nanozyme was correlated with the pH of the reaction solution and the inhibitory effects of the three biothiols on the nanozyme-triggered chromogenic system differed in the specific pH environments. Therefore, each sensing unit of this electronic tongue generated differential colorimetric fingerprints of different biothiols. After principal component analysis (PCA), the developed novel colorimetric sensor array can accurately discriminate biothiols between different types, various concentrations, and different mixture proportions. Further, the sensor array was used for the colorimetric identification of real serum and cellular samples, demonstrating its great potential in tumor diagnostic applications.

Exploring the relationship between oxidative stress status and inflammatory markers during primary Sjögren's syndrome: A new approach for patient monitoring

INTRODUCTION

Primary Sjögren's syndrome (pSS) is a chronic inflammatory disease primarily affects exocrine glands dysfunction. Oxidative stress (OS) is a phenomenon occurring as a result of an imbalance between the generation of free radicals and antioxidant defense system. Hence, we aimed to establish the status of OS and inflammatory response according to the pSS disease activity index. In this context, we investigated malondialdehyde (MDA), and antioxidant enzymes during pSS. The possible association between MDA and nitric oxide (NO) levels and between MDA and some pro-inflammatory cytokines (IL-1β, IL-6, TNF-α, and IL-33).

METHODS

The study has been conducted on 53 pSS patients. The antioxidant enzymes, represented by glutathione peroxidase (GSH-Px), catalase (CAT) and superoxide dismutase (SOD), were estimated by a colorimetric activity kit. Whereas, MDA value was assessed by measuring thiobarbituric acid reactive substances. Moreover, pro-inflammatory cytokines (IL-1β, IL-6, TNF-α, and IL-33) and NO were respectively quantified by enzyme-linked immunosorbent assays (ELISA) and the modified Griess.

RESULTS

Interestingly, we report a notable reduction in our pSS patients' antioxidant enzyme activity, while NO, MDA and proinflammatory cytokines values were significantly increased. pSS patients with higher disease activity had much stronger increases in NO and MDA levels. No significant difference was assessed in CRP level. Additionally, substantial significant correlations between plasmatic NO and MDA levels and between MDA, NO and IL-1β, IL-6, TNF-α cytokines were reported. However, no significant association was found between NO, MDA and IL-33 concentrations.

CONCLUSION

Collectively, our data showed altered oxidant-antioxidant balance in pSS patients. MDA, NO, IL-1β, IL-6, TNF-α seem to be good indicators in monitoring disease activity. Oxidative stress was closely related to inflammation in pSS. Exploiting this relationship might provide valuable indicators in the follow-up and prognosis of pSS with a potential therapeutic value.

The Role of Glutathione in Selected Viral Diseases

During inflammatory processes, immunocompetent cells are exposed to substantial amounts of free radicals and toxic compounds. Glutathione is a cysteine-containing tripeptide that is an important and ubiquitous antioxidant molecule produced in human organs. The intracellular content of GSH regulates the detoxifying capacity of cells, as well as the inflammatory and immune response. GSH is particularly important in the liver, where it serves as the major non-protein thiol involved in cellular antioxidant defense. There are numerous causes of hepatitis. The inflammation of the liver can be caused by a variety of infectious viruses. The relationship between oxidative stress and the hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), and hepatitis E virus (HEV) infection is not fully known. The aim of this study was to examine the relationship between hepatotropic viruses and glutathione status, including reduced glutathione (GSH) and oxidized glutathione (GSSG), as well as antioxidant enzymes, e.g., glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione-S-transferase (GST) in liver diseases.

Immunomodulatory, apoptotic and anti-proliferative potentials of sildenafil in Ehrlich ascites carcinoma murine model: In vivo and in silico insights

Sildenafil is a potent phosphodiesterase-5 (PDE5) inhibitor that effectively inhibits cGMP and increases the strength of nitric oxide. PDE5 was overexpressed in several carcinomas, including breast cancer, which inhibited tumor growth and cell division. The current research aims to investigate the in vivo sildenafil's immunomodulatory and antineoplastic potentials against Ehrlich Ascites Carcinoma. This study looked at the effects of sildenafil mono-treatment and co-treatment with cisplatin; tumor cell count, viability and the inhibition rate were determined. Apoptosis, cell cycle distribution, alterations in tumor cells and splenocytes proliferation, changes in splenocytes immunophenotyping using flowcytometry, plasma levels of malondialdehyde (MDA), reduced glutathione (GSH), interferone (IFN)-γ, granzyme B, alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea, creatinine and hematological alterations were detected. Additionally, docking study was conducted to get further insights on how Sildenafil exerts its activity. Sildenafil mono-treatment and co-treatment with cisplatin markedly reduced tumor cell count, viability, growth rate and proliferative capability accompanied by apoptosis enhancement and G₀/G₁ and sub G₁ cells cycle arrest. Fortunately, sildenafil evoked efficient cellular immune response by increasing plasma levels of granzyme B and IFN-γ, proportion of splenic T cytotoxic (CD3⁺CD8⁺) and T helper (CD3⁺CD4⁺), accompanied by decrease in the proportion of splenic regulatory T cells. . Moreover, in silico data suggest LcK and MAPKs as the potential targets of sildenafil. Furthermore, sildenafil rebalanced the oxidant-antioxidant status by decreasing MDA and increasing GSH plasma levels. Sildenafil successfully retrieved various hematological values besides renal and hepatic functions in EAC-bearing animals. In conclusion, our results suggest that sildenafil could be potential safe anti-tumor agent with immuno-modulatory properties against Ehrlich ascites carcinoma.

S-Glutathionylation-Controlled Apoptosis of Lung Epithelial Cells; Potential Implications for Lung Fibrosis

Glutathione (GSH), a major antioxidant in mammalian cells, regulates several vital cellular processes, such as nutrient metabolism, protein synthesis, and immune responses. In addition to its role in antioxidant defense, GSH controls biological processes through its conjugation to reactive protein cysteines in a post-translational modification known as protein S-glutathionylation (PSSG). PSSG has recently been implicated in the pathogenesis of multiple diseases including idiopathic pulmonary fibrosis (IPF). Hallmarks of IPF include repeated injury to the alveolar epithelium with aberrant tissue repair, epithelial cell apoptosis and fibroblast resistance to apoptosis, and the accumulation of extracellular matrix and distortion of normal lung architecture. Several studies have linked oxidative stress and PSSG to the development and progression of IPF. Additionally, it has been suggested that the loss of epithelial cell homeostasis and increased apoptosis, accompanied by the release of various metabolites, creates a vicious cycle that aggravates disease progression. In this short review, we highlight some recent studies that link PSSG to epithelial cell apoptosis and highlight the potential implication of metabolites secreted by apoptotic cells.

Dynamic thiol disulphide homeostasis in patients with surfer's eye: a case-control study

PURPOSE

The role of oxidative stress in the pathogenesis of pterygium is still unclear. However, abnormal thiol disulfide homeostasis levels are involved in the pathogenesis of various systemic or ocular diseases. We aim to analyze dynamic thiol disulphide homeostasis in patients suffering from conjunctival pterygium using a contemporary technique.

METHODS

Thirty-eight subjects suffering from pterygium and 35 age-gender matched healthy volunteers were recruited for the study. For each case, total thiol, disulfide and native thiol levels in blood were obtained. Additionally, the ratio of disulfide over total thiol, native thiol over total thiol and disulfide over native thiol were computed.

RESULTS

The level of median native thiol was lower in pterygium group (318.2 µmol/L vs. 333.4 µmol/L) and median disulfide was slightly higher in pterygium group (24.3 µmol/L vs. 22.8 µmol/L) compared to control group. Both disulfide over total thiol and disulfide over native thiol ratios were higher in pterygium group, ratio of native thiol over total thiol was found to be higher in control group. Nevertheless, none of those differences were statistically significant at 95% confidence level. Notably, correlation test pointed to a negative correlation both between pterygium grade and native thiol and between total thiol and pterygium grade in pterygium group (P = 0.03 and 0.02, respectively).

CONCLUSION

A negative correlation hinting that slightly weakened dynamic thiol disulphide homeostasis in subjects with pterygium, a local ocular disease. Further studies with larger sample sizes may shed light on this potential relationship and justify systemic antioxidant therapies in these cases.

Role of protein phosphatase 2A in kidney disease (Review)

Kidney disease affects millions of people worldwide and is a financial burden on the healthcare system. Protein phosphatase 2A (PP2A), which is involved in renal development and the function of ion-transport proteins, aquaporin-2 and podocytes, is likely to serve an important role in renal processes. PP2A is associated with the pathogenesis of a variety of different kidney diseases including podocyte injury, inflammation, tumors and chronic kidney disease. The current review aimed to discuss the structure and function of PP2A subunits in the context of kidney diseases. How dysregulation of PP2A in the kidneys causes podocyte death and the inactivation of PP2A in renal carcinoma tissues is discussed. Inhibition of PP2A activity prevents epithelial-mesenchymal transition and attenuates renal fibrosis, creating a favorable inflammatory microenvironment and promoting the initiation and progression of tumor pathogenesis. The current review also indicates that PP2A serves an important role in protection against renal inflammation. Understanding the detailed mechanisms of PP2A provides information that can be utilized in the design and application of novel therapeutics for the treatment and prevention of renal diseases.

Ethnically biased microsatellites contribute to differential gene expression and glutathione metabolism in Africans and Europeans

Approximately three percent of the human genome is occupied by microsatellites: a type of short tandem repeat (STR). Microsatellites have well established effects on (a) the genetic structure of diverse human populations and (b) expression of nearby genes. These lines of inquiry have uncovered 3,984 ethnically biased microsatellite loci (EBML) and 28,375 expression STRs (eSTRs), respectively. We hypothesize that a combination of EBML, eSTRs, and gene expression data (RNA-seq) can be used to show that microsatellites contribute to differential gene expression and phenotype in human populations. In fact, our previous study demonstrated a degree of mutual overlap between EBML and eSTRs but fell short of quantifying effects on gene expression. The present work aims to narrow the gap. First, we identify 313 overlapping EBML/eSTRs and recapitulate their mutual overlap. The 313 EBML/eSTRs are then characterized across ethnicity and tissue type. We use RNA-seq data to pursue validation of 49 regions that affect whole blood gene expression; 32 out of 54 affected genes are differentially expressed in Africans and Europeans. We quantify the relative contribution of these 32 genes to differential expression; fold change tends to be less than other differentially expressed genes. Repeat length correlates with expression for 15 of the 32 genes; two are conspicuously involved in glutathione metabolism. Finally, we repurpose a mathematical model of glutathione metabolism to investigate how a single polymorphic microsatellite affects phenotype. We conclude with a testable prediction that microsatellite polymorphisms affect GPX7 expression and oxidative stress in Africans and Europeans.

Protein Expression of Angiotensin-Converting Enzyme 2 (ACE2) is Upregulated in Brains with Alzheimer's Disease

Alzheimer’s disease is a chronic neurodegenerative disorder and represents the main cause of dementia globally. Currently, the world is suffering from the coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a virus that uses angiotensin-converting enzyme 2 (ACE2) as a receptor to enter the host cells. In COVID-19, neurological manifestations have been reported to occur. The present study demonstrates that the protein expression level of ACE2 is upregulated in the brain of patients with Alzheimer’s disease. The increased ACE2 expression is not age-dependent, suggesting the direct relationship between Alzheimer’s disease and ACE2 expression. Oxidative stress has been implicated in the pathogenesis of Alzheimer’s disease, and brains with the disease examined in this study also exhibited higher carbonylated proteins, as well as an increased thiol oxidation state of peroxiredoxin 6 (Prx6). A moderate positive correlation was found between the increased ACE2 protein expression and oxidative stress in brains with Alzheimer’s disease. In summary, the present study reveals the relationships between Alzheimer’s disease and ACE2, the receptor for SARS-CoV-2. These results suggest the importance of carefully monitoring patients with both Alzheimer’s disease and COVID-19 in order to identify higher viral loads in the brain and long-term adverse neurological consequences.

Comparative transcriptome analysis of SARS-CoV, MERS-CoV, and SARS-CoV-2 to identify potential pathways for drug repurposing

The ongoing COVID-19 pandemic caused by the coronavirus, SARS-CoV-2, has already caused in excess of 1.25 million deaths worldwide, and the number is increasing. Knowledge of the host transcriptional response against this virus and how the pathways are activated or suppressed compared to other human coronaviruses (SARS-CoV, MERS-CoV) that caused outbreaks previously can help in the identification of potential drugs for the treatment of COVID-19. Hence, we used time point meta-analysis to investigate available SARS-CoV and MERS-CoV in-vitro transcriptome datasets in order to identify the significant genes and pathways that are dysregulated at each time point. The subsequent over-representation analysis (ORA) revealed that several pathways are significantly dysregulated at each time point after both SARS-CoV and MERS-CoV infection. We also performed gene set enrichment analyses of SARS-CoV and MERS-CoV with that of SARS-CoV-2 at the same time point and cell line, the results of which revealed that common pathways are activated and suppressed in all three coronaviruses. Furthermore, an analysis of an in-vivo transcriptomic dataset of COVID-19 patients showed that similar pathways are enriched to those identified in the earlier analyses. Based on these findings, a drug repurposing analysis was performed to identify potential drug candidates for combating COVID-19.

Angiotensin-converting enzyme 2 (ACE2) is upregulated in Alzheimer's disease brain

Alzheimer's disease is a chronic neurodegenerative disorder and represents the main cause of dementia. Currently, the world is suffering from the pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that uses angiotensin-converting enzyme 2 (ACE2) as a receptor to enter the host cells. In COVID-19, neurological manifestations have been reported to occur. The present study demonstrates that the protein expression level of ACE2 is upregulated in the brain of Alzheimer's disease patients. The increased ACE2 expression is not age-dependent, suggesting the direct relationship between Alzheimer's disease and the ACE2 expression. Oxidative stress has been implicated in the pathogenesis of Alzheimer's disease, and Alzheimer's disease brains examined in this study also exhibited higher carbonylated proteins as well as increased thiol oxidation state of peroxiredoxin 6 (Prx6). The positive correlation was found between the increased ACE2 protein expression and oxidative stress in Alzheimer's disease brain. Thus, the present study reveals the relationships between Alzheimer's disease and ACE2, the receptor for SARS-CoV-2. These results warrant monitoring Alzheimer's disease patients with COVID-19 carefully for the possible higher viral load in the brain and long-term adverse neurological consequences.

Activity of Antioxidant Enzymes in the Tumor and Adjacent Noncancerous Tissues of Non-Small-Cell Lung Cancer

Lung tissue is directly exposed to high oxygen pressure, as well as increased endogenous and exogenous oxidative stress. Reactive oxygen species (ROS) generated in these conditions play an important role in the initiation and promotion of neoplastic growth. In response to oxidative stress, the antioxidant activity increases and minimizes ROS-induced injury in experimental systems. The aim of the present study was to evaluate the activity of antioxidant enzymes, such as superoxide dismutase (SOD; isoforms: Cu/ZnSOD and MnSOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione S-transferase (GST), along with the concentration of malondialdehyde (MDA) in tumor and adjacent noncancerous tissues of two histological types of NSCLC, i.e., adenocarcinoma and squamous cell carcinoma, collected from 53 individuals with surgically resectable NSCLC. MDA concentration was similar in tumors compared with adjacent noncancerous tissues. Tumor cells had low MnSOD activity, usually low Cu/ZnSOD activity, and almost always low catalase activity compared with those of the corresponding tumor-free lung tissues. Activities of GSH-related enzymes were significantly higher in tumor tissues, irrespective of the histological type of cancer. This pattern of antioxidant enzymes activity could possibly be the way by which tumor cells protect themselves against increased oxidative stress.

Aspergillus oryzae spore germination is enhanced by non-thermal atmospheric pressure plasma

Poor and unstable culture growth following isolation presents a technical barrier to the efficient application of beneficial microorganisms in the food industry. Non-thermal atmospheric pressure plasma is an effective tool that could overcome this barrier. The objective of this study was to investigate the potential of plasma to enhance spore germination, the initial step in fungal colonization, using Aspergillus oryzae, a beneficial filamentous fungus used in the fermentation industry. Treating fungal spores in background solutions of phosphate buffered saline (PBS) and potato dextrose broth (PDB) with micro dielectric barrier discharge plasma using nitrogen gas for 2 and 5 min, respectively, significantly increased the germination percentage. Spore swelling, the first step in germination, was accelerated following plasma treatment, indicating that plasma may be involved in loosening the spore surface. Plasma treatment depolarized spore membranes, elevated intracellular Ca²⁺ levels, and activated mpkA, a MAP kinase, and the transcription of several germination-associated genes. Our results suggest that plasma enhances fungal spore germination by stimulating spore swelling, depolarizing the cell membrane, and activating calcium and MAPK signaling.

Aphid-Triggered Changes in Oxidative Damage Markers of Nucleic Acids, Proteins, and Lipids in Maize (Zea mays L.) Seedlings

Prior experiments illustrated reactive oxygen species (ROS) overproduction in maize plants infested with bird-cherry-oat (Rhopalosiphum padi L.) aphids. However, there is no available data unveiling the impact of aphids feeding on oxidative damages of crucial macromolecules in maize tissues. Therefore, the purpose of the current study was to evaluate the scale of oxidative damages of genomic DNA, total RNA and mRNA, proteins, and lipids in seedling leaves of two maize genotypes (Złota Karłowa and Waza cvs—susceptible and relatively resistant to the aphids, respectively). The content of oxidized guanosine residues (8-hydroxy-2′-deoxyguanosine; 8-OHdG) in genomic DNA, 8-hydroxyguanosine (8-OHG) in RNA molecules, protein carbonyl groups, total thiols (T-SH), protein-bound thiols (PB-SH), non-protein thiols (NP-SH), malondialdehyde (MDA) and electrolyte leakage (EL) levels in maze plants were determined. In addition, the electrical penetration graphs (EPG) technique was used to monitor and the aphid stylet positioning and feeding modes in the hosts. Maize seedlings were infested with 0 (control), 30 or 60 R. padi adult apterae per plant. Substantial increases in the levels of RNA, protein and lipid oxidation markers in response to aphid herbivory, but no significant oxidative damages of genomic DNA, were found. Alterations in the studied parameters were dependent on maize genotype, insect abundance and infestation time.

Protein Redox State Monitoring Studies of Thiol Reactivity

Protein cysteine thiol status is a major determinant of oxidative stress and oxidant signaling. The -SulfoBiotics- Protein Redox State Monitoring Kit provides a unique opportunity to investigate protein thiol states. This system adds a 15-kDa Protein-SHifter to reduced cysteine residues, and this molecular mass shift can be detected by gel electrophoresis. Even in biological samples, Protein-SHifter Plus allows the thiol states of specific proteins to be studied using Western blotting. Peroxiredoxin 6 (Prx6) is a unique one-cysteine peroxiredoxin that scavenges peroxides by utilizing conserved Cysteine-47. Human Prx6 also contains an additional non-conserved cysteine residue, while rat Prx6 only has the catalytic cysteine. In cultured cells, cysteine residues of Prx6 were found to be predominantly fully reduced. The treatment of human cells with hydrogen peroxide (H₂O₂) formed Prx6 with one cysteine reduced. Since catalytic cysteine becomes oxidized in rat cells by the same H₂O₂ treatment and treating denatured human Prx6 with H₂O₂ results in the oxidation of both cysteines, non-conserved cysteine may not be accessible to H₂O₂ in human cells. We also found that untreated cells contained Prx6 multimers bound through disulfide bonds. Surprisingly, treating cells with H₂O₂ eliminated these Prx6 multimers. In contrast, treating cell lysates with H₂O₂ promoted the formation of Prx6 multimers. Similarly, treating purified preparations of the recombinant cyclic nucleotide-binding domain of the human hyperpolarization-activated cyclic nucleotide-modulated channels with H₂O₂ promoted the formation of multimers. These studies revealed that the cellular environment defines the susceptibility of protein cysteines to H₂O₂ and determines whether H₂O₂ acts as a facilitator or a disrupter of disulfide bonds.

Metabolomic insights of macrophage responses to graphene nanoplatelets: Role of scavenger receptor CD36

Graphene nanoplatelets (GNPs) are novel two-dimensional engineered nanomaterials consisting of planar stacks of graphene. Although human exposures are increasing, our knowledge is lacking regarding immune-specific responses to GNPs and mechanisms of interactions. Our current study utilizes a metabolite profiling approach to evaluate macrophage responses to GNPs. Furthermore, we assessed the role of the scavenger receptor CD36 in mediating these GNP-induced responses. GNPs were purchased with dimensions of 2 μm × 2 μm × 12 nm. Macrophages were exposed to GNPs at different concentrations of 0, 25, 50, or 100 μg/ml for 1, 3, or 6 h. Following exposure, no cytotoxicity was observed, while GNPs readily associated with macrophages in a concentration-dependent manner. After the 1h-pretreatment of either a CD36 competitive ligand sulfo-N-succinimidyl oleate (SSO) or a CD36 specific antibody, the cellular association of GNPs by macrophages was significantly reduced. GNP exposure was determined to alter mitochondrial membrane potential while the pretreatment with a CD36 antibody inhibited these changes. In a separate exposure, macrophages were exposed to GNPs at concentrations of 0, 50, or 100 μg/mL for 1 or 3h or 100 μM SSO (a CD36 specific ligand) for 1h and collected for metabolite profiling. Principal component analysis of identified compounds determined differential grouping based on exposure conditions. The number of compounds changed following exposure was determined to be both concentration- and time-dependent. Identified metabolites were determined to relate to several metabolism pathways such as glutathione metabolism, Pantothenate and CoA biosynthesis, Sphingolipid metabolism, Purine metabolism, arachidonic acid metabolism and others. Lastly, a number of metabolites were found in common between cells exposed to the CD36 receptor ligand, SSO, and GNPs suggesting both CD36-dependent and independent responses to GNP exposure. Together our data demonstrates GNP-macrophage interactions, the role of CD36 in the cellular response, and metabolic pathways disrupted due to exposure.

Possible Synergistic Effects of Glutathione and C-Reactive Protein in the Progression of Liver Cirrhosis

Liver cirrhosis is often associated with increased inflammatory responses and changes of glutathione (GSH) status. The possible interactions between these two factors in mediating damages of liver function remain unclear. Here, we measured the inflammatory responses and GSH status in liver cirrhotic patients and compared them with healthy subjects. In addition, we assessed the relationship of the GSH status and levels of inflammatory markers with the severity of the disease. This was a cross-sectional study. In total, we recruited 63 liver cirrhotic patients with Child⁻Turcotte⁻Pugh class A scores, and 12 patients with class B⁻C scores, together with 110 healthy subjects. Patients with class B⁻C scores showed the highest level of high-sensitivity C-reactive protein (hs-CRP) when compared with class A patients or healthy subjects. Patients in class A group had significantly higher GSH levels when compared with class B⁻C group or healthy subjects. After adjusting for potential confounders and each other, serum hs-CRP levels showed positive association with the Child⁻Turcotte⁻Pugh scores, while GSH levels showed negative association with Child⁻Turcotte⁻Pugh scores. Interactions were found between levels of plasma GSH and serum hs-CRP (β = 0.004, p = 0.016). CRP and GSH levels, which had showed interactions, were associated with the severity of liver cirrhosis.

Glutathione: Antioxidant Properties Dedicated to Nanotechnologies

Which scientist has never heard of glutathione (GSH)? This well-known low-molecular-weight tripeptide is perhaps the most famous natural antioxidant. However, the interest in GSH should not be restricted to its redox properties. This multidisciplinary review aims to bring out some lesser-known aspects of GSH, for example, as an emerging tool in nanotechnologies to achieve targeted drug delivery. After recalling the biochemistry of GSH, including its metabolism pathways and redox properties, its involvement in cellular redox homeostasis and signaling is described. Analytical methods for the dosage and localization of GSH or glutathiolated proteins are also covered. Finally, the various therapeutic strategies to replenish GSH stocks are discussed, in parallel with its use as an addressing molecule in drug delivery.

Suppression of PKC causes oncogenic stress for triggering apoptosis in cancer cells

Gain of functional mutations in ras occurs in more than 30% of human malignancies and in particular 90% of pancreatic cancer. Mutant ras, via activating multiple effector pathways, not only promote cell growth or survival, but also apoptosis, depending upon cell types or circumstances. In order to further study the mechanisms of apoptosis induced by oncogenic ras, we employed the ras loop mutant genes and demonstrated that Akt functioned downstream of Ras in human pancreatic cancer or HPNE cells ectopically expressing mutated K-ras for the induction of apoptosis after the concurrent suppression of PKC α and β. In this apoptotic process, the redox machinery was aberrantly switched on in the pancreatic cancer cells as well as prostate cancer DU145 cells. p73 was phosphorylated and translocated to the nucleus, accompanied with UPR activation and induction of apoptosis. The in vitro results were corroborated by the in vivo data. Thus, our study indicated that PKC α and β appeared coping with oncogenic Ras or mutated Akt to maintain the balance of the homeostasis in cancer cells. Once these PKC isoforms were suppressed, the redox state in the cancer cells was disrupted, which elicited persistent oncogenic stress and subsequent apoptotic crisis.

Glycine Increases Insulin Sensitivity and Glutathione Biosynthesis and Protects against Oxidative Stress in a Model of Sucrose-Induced Insulin Resistance

Oxidative stress and redox status play a central role in the link between insulin resistance (IR) and lipotoxicity in metabolic syndrome. This mechanistic link may involve alterations in the glutathione redox state. We examined the effect of glycine supplementation to diet on glutathione biosynthesis, oxidative stress, IR, and insulin cell signaling in liver from sucrose-fed (SF) rats characterized by IR and oxidative stress. Our hypothesis is that the correction of glutathione levels by glycine treatment leads to reduced oxidative stress, a mechanism associated with improved insulin signaling and IR. Glycine treatment decreases the levels of oxidative stress markers in liver from SF rats and increases the concentrations of glutathione (GSH) and γ-glutamylcysteine and the amount of γ-glutamylcysteine synthetase (γ-GCS), a key enzyme of GSH biosynthesis in liver from SF rats. In liver from SF rats, glycine also decreases the insulin-induced phosphorylation of insulin receptor substrate-1 (ISR-1) in serine residue and increases the phosphorylation of insulin receptor β-subunit (IR-β) in tyrosine residue. Thus, supplementing diets with glycine to correct GSH deficiency and to reduce oxidative stress provides significant metabolic benefits to SF rats by improving insulin sensitivity.

Cell signaling promoting protein carbonylation does not cause sulfhydryl oxidation: Implications to the mechanism of redox signaling

Reactive oxygen species (ROS) have been recognized as second messengers, however, targeting mechanisms for ROS in cell signaling have not been defined. While ROS oxidizing protein cysteine thiols has been the most popular proposed mechanism, our laboratory proposed that ligand/receptor-mediated cell signaling involves protein carbonylation. Peroxiredoxin-6 (Prx6) is one protein that is carbonylated at 10 min after the platelet-derived growth factor (PDGF) stimulation of human pulmonary artery smooth muscle cells. In the present study, the SulfoBiotics Protein Redox State Monitoring Kit Plus (Dojindo Molecular Technologies) was used to test if cysteine residues of Prx6 are oxidized in response to the PDGF stimulation. Human Prx6 has a molecular weight of 25 kDa and contains two cysteine residues. The Dojindo system adds the 15 kDa Protein-SHifter if these cysteine residues are reduced in the cells. Results showed that, in untreated cells, the Prx6 molecule predominantly exhibited the 55 kDa band, indicating that both cysteine residues are reduced in the cells. Treatment of cells with 1 mM H ₂O ₂ caused the disappearance of the 55 kDa band and the appearance of a 40 kDa band, suggesting that the high concentration of H ₂O ₂ oxidized one of the two cysteine residues in the Prx6 molecule. By contrast, PDGF stimulation had no effects on the thiol status of the Prx6 molecule. We concluded that protein carbonylation is a more sensitive target of ROS during ligand/receptor-mediated cell signaling than sulfhydryl oxidation.

One-year follow-up of clinical, metabolic and oxidative stress profile of morbid obese patients after laparoscopic sleeve gastrectomy. 8-oxo-dG as a clinical marker

Obesity has grown worldwide over the last few decades. In its different degrees, obesity is accompanied by many clinical and biochemical alterations reflecting the pathological condition of various body tissues. Among the mechanisms underlying the pathogenesis of obesity and associated complications, oxidative stress (OS) may be playing an important role. In the present study, we have characterized at systemic level the degree of OS status in a group of morbid obese patients (BMI>40kg/m²) at basal sate and its modulation during one year after bariatric surgery using the laparoscopic sleeve gastrectomy (LSG) technique. As compared with normal weight subjects matched in age, peripheral blood mononuclear cells (PBMc) of obese patients present a significant reduction of the antioxidant enzyme activities superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) as well as a significant increase of the oxidized/reduced glutathione ratio (GSSG/GSH) in these cells. Lipid peroxidation is significantly increased in the patient group as shown by the increased levels of malondialdehyde (MDA) in PBMc and the amount of F2-Isoprostanes (F2-IsoPs) released in urine. In addition, the DNA damage product 8-oxo-7,8-2'-deoxyguanosine (8-oxo-dG) was also observed to be increased in serum and urine of morbid obese patients as compared with the control group. After LSG, an improvement of their ponderal and metabolic profile was accompanied by a progressive recovery of antioxidant enzyme activities and the decline of oxidative byproducts both in PBMc and biological fluids. The observed changes of urinary 8-oxo-dG levels correlate positively with its serum concentration, the lipid peroxidation products MDA and F2-IsoPs, triglycerides, glucose, insulin, HOMA index and body weight and negatively with the percentage of weight and BMI loss and antioxidant activities. We conclude that the analysis of urinary 8-oxo-dG could be validated as a useful marker for the monitoring of ponderal and metabolic status of morbid obese patients.

Changes of Oxidative Stress, Glutathione, and Its Dependent Antioxidant Enzyme Activities in Patients with Hepatocellular Carcinoma before and after Tumor Resection

The changes in and relationship between oxidative stress and the glutathione (GSH) antioxidant system in the plasma and tissues of patients with hepatocellular carcinoma (HCC) before and after tumor resection have not been clearly determined. We investigated the changes in oxidative stress, GSH status and its dependent antioxidant enzyme activities in HCC patients before and after tumor resection, and to determine the association of oxidative stress with GSH and its dependent antioxidant enzyme activities in plasma and tissues. This study employed a cross-sectional design. Forty-four men and 16 women with HCC were recruited. Fasting blood was drawn on the day before the tumor resection and one month after the tumor resection. HCC tissue and adjacent normal liver tissue were obtained at the time of surgical resection. Patients had significantly increased plasma malondialdehyde (MDA) and oxidized-low density lipoprotein levels but decreased GSH and oxidized GSH levels before tumor resection compared with the corresponding post-resection values. GSH and trolox equivalent antioxidant capacity (TEAC) levels and activities of GSH peroxidase were significantly increased while MDA level was significantly lower in HCC tissue when compared with the adjacent normal tissue. The pre-resection plasma MDA level was significantly correlated with pre-resection plasma GSH concentration, and MDA level in HCC and adjacent normal tissues. Pre-resection plasma GSH concentration was significantly correlated with GSH and TEAC level in HCC tissue. HCC patients had increased oxidative stress, decreased GSH, and lower dependent antioxidant capacities before tumor resection. However, hepatocellular tumor had increased GSH and TEAC levels as well as GSH peroxidase activities which might protect itself against increased oxidative stress.

FABP4/aP2 Regulates Macrophage Redox Signaling and Inflammasome Activation via Control of UCP2

Obesity-linked metabolic disease is mechanistically associated with the accumulation of proinflammatory macrophages in adipose tissue, leading to increased reactive oxygen species (ROS) production and chronic low-grade inflammation. Previous work has demonstrated that deletion of the adipocyte fatty acid-binding protein (FABP4/aP2) uncouples obesity from inflammation via upregulation of the uncoupling protein 2 (UCP2). Here, we demonstrate that ablation of FABP4/aP2 regulates systemic redox capacity and reduces cellular protein sulfhydryl oxidation and, in particular, oxidation of mitochondrial protein cysteine residues. Coincident with the loss of FABP4/aP2 is the upregulation of the antioxidants superoxide dismutase (SOD2), catalase, methionine sulfoxide reductase A, and the 20S proteasome subunits PSMB5 and αβ. Reduced mitochondrial protein oxidation in FABP4/aP2^-/- macrophages attenuates the mitochondrial unfolded-protein response (mtUPR) as measured by expression of heat shock protein 60, Clp protease, and Lon peptidase 1. Consistent with a diminished mtUPR, FABP4/aP2^-/- macrophages exhibit reduced expression of cleaved caspase-1 and NLRP3. Secretion of interleukin 1β (IL-1β), in response to inflammasome activation, is ablated in FABP4/aP2^-/- macrophages, as well as in FABP4/aP2 inhibitor-treated cells, but partially rescued in FABP4/aP2-null macrophages when UCP2 is silenced. Collectively, these data offer a novel pathway whereby FABP4/aP2 regulates macrophage redox signaling and inflammasome activation via control of UCP2 expression.

Oxidative Stress during HIV Infection: Mechanisms and Consequences

It is generally acknowledged that reactive oxygen species (ROS) play crucial roles in a variety of natural processes in cells. If increased to levels which cannot be neutralized by the defense mechanisms, they damage biological molecules, alter their functions, and also act as signaling molecules thus generating a spectrum of pathologies. In this review, we summarize current data on oxidative stress markers associated with human immunodeficiency virus type-1 (HIV-1) infection, analyze mechanisms by which this virus triggers massive ROS production, and describe the status of various defense mechanisms of the infected host cell. In addition, we have scrutinized scarce data on the effect of ROS on HIV-1 replication. Finally, we present current state of knowledge on the redox alterations as crucial factors of HIV-1 pathogenicity, such as neurotoxicity and dementia, exhaustion of CD4+/CD8+ T-cells, predisposition to lung infections, and certain side effects of the antiretroviral therapy, and compare them to the pathologies associated with the nitrosative stress.

Role of ROS and RNS Sources in Physiological and Pathological Conditions

There is significant evidence that, in living systems, free radicals and other reactive oxygen and nitrogen species play a double role, because they can cause oxidative damage and tissue dysfunction and serve as molecular signals activating stress responses that are beneficial to the organism. Mitochondria have been thought to both play a major role in tissue oxidative damage and dysfunction and provide protection against excessive tissue dysfunction through several mechanisms, including stimulation of opening of permeability transition pores. Until recently, the functional significance of ROS sources different from mitochondria has received lesser attention. However, the most recent data, besides confirming the mitochondrial role in tissue oxidative stress and protection, show interplay between mitochondria and other ROS cellular sources, so that activation of one can lead to activation of other sources. Thus, it is currently accepted that in various conditions all cellular sources of ROS provide significant contribution to processes that oxidatively damage tissues and assure their survival, through mechanisms such as autophagy and apoptosis.

Cigarette smoke compounds induce cellular redox imbalance, activate NF-κB, and increase TNF-α/CRP secretion: a possible pathway in the pathogenesis of COPD

Cigarette smoke has always been considered as a risk factor for chronic obstructive pulmonary diseases (COPD). In this study, we have examined the effect of ten individual cigarette smoke compounds (nicotine, benzo[a]pyrene, naphthalene, formaldehyde, ammonia, acrylic acid, toluene, benzene, m-xylene, and hexamine) on glutathione S transferase (GST) activity, an important Phase II metabolic enzyme and their possible role in inflammatory pathophysiology leading to COPD. Lower Glutathione (GSH) levels and GST activity and higher CRP, TNF-α, and IL-6 levels were observed in COPD patients compared to age and gender-matched controls. Using human recombinant GST and plasma as well as erythrocytes collected from normal subjects this study demonstrates that out of the ten compounds, nicotine (5 mg mL^-1), benzo[a]pyrene (10 ng mL^-1), naphthalene (250 μg mL^-1), and formaldehyde (5 pg mL^-1) caused a significant decrease in recombinant, plasma, and erythrocyte GST activity. Further cell culture studies show that exposure to nicotine, benzo[a]pyrene, naphthalene, and formaldehyde caused a significant decrease in GSH levels and GST activity and its protein expression and an increase in intracellular ROS production in THP-1 monocytes. Interestingly, treatment with benzo[a]pyrene and naphthalene significantly up regulated the phosphorylation of the p65 subunit of NF-κB and increased the secretion of TNF-α and CRP compared to control. This study suggests the potential role of benzo[a]pyrene and naphthalene in the activation of the inflammatory signaling pathway leading to cigarette smoke-induced COPD.

A minimalist fluorescent probe for differentiating Cys, Hcy and GSH in live cells

A simple molecule, tetrafluoroterephthalonitrile (4F-2CN), was discovered to be an efficient fluorescent probe for detecting biological thiol species. The probe responded to Cys and emitted strong green fluorescence, whereas it reacted with Hcy/GSH and generated blue fluorescence. Addition of CTAB (cetyl trimethylammonium bromide) was observed to alter the fluorescence color of the reaction product of 4F-2CN and Hcy (from blue to green), but no alteration of the fluorescence color occurred for Cys and GSH. For the very first time, cell imaging experiments showed that the three commonly occurring thiols (Cys/Hcy/GSH) could be differentiated using a single fluorescent probe. In addition, the reaction product of 4F-2CN and Cys exhibits two-photon properties, offering a potentially useful tool for tissue imaging studies. To the best of our knowledge, 4F-2CN is currently the smallest fluorescent probe for thiol detection. We envision that this new and versatile probe will be a useful tool for further elucidating the roles of thiols in biology.

[Main Cellular Redox Couples]

Most of the living cells maintain the continuous flow of electrons, which provides them by energy. Many of the compounds are presented in a cell at the same time in the oxidized and reduced states, forming the active redox couples. Some of the redox couples, such as NAD+/NADH, NADP+/NADPH, oxidized/reduced glutathione (GSSG/GSH), are universal, as they participate in adjusting of many cellular reactions. Ratios of the oxidized and reduced forms of these compounds are important cellular redox parameters. Modern research approaches allow setting the new functions of the main redox couples in the complex organization of cellular processes. The following information is about the main cellular redox couples and their participation in various biological processes.

Decoding the oxidative stress hypothesis in diabetic embryopathy through proapoptotic kinase signaling

Maternal diabetes-induced birth defects occur in 6-10% of babies born to mothers with pregestational diabetes, representing a significant maternal-fetal health problem. Currently, these congenital malformations represent a significant maternal-fetal medicine issue, but are likely to create an even greater public health threat as 3 million women of reproductive age (19-44 years) have diabetes in the United States alone, and this number is expected to double by 2030. Neural tube defects (NTDs) and congenital heart defects are the most common types of birth defects associated with maternal diabetes. Animal studies have revealed that embryos under hyperglycemic conditions exhibit high levels of oxidative stress resulting from enhanced production of reactive oxygen species and impaired antioxidant capability. Oxidative stress activates a set of proapoptotic kinase signaling intermediates leading to abnormal cell death in the embryonic neural tube, which causes NTD formation. Work in animal models also has revealed that maternal diabetes triggers a series of signaling intermediates: protein kinase C (PKC) isoforms, PKCα, βII and δ; apoptosis signal-regulating kinase 1; c-Jun-N-terminal kinase (JNK)1/2; caspase; and apoptosis. Specifically, maternal diabetes in rodent models activates the proapoptotic unfolded protein response and endoplasmic reticulum (ER) stress. A reciprocal causation between JNK1/2 activation and ER stress exists in diabetic embryopathy. Molecular studies further demonstrate that deletion of the genes for Prkc, Ask1, Jnk1, or Jnk2 abolishes maternal diabetes-induced neural progenitor apoptosis and ameliorates NTD formation. Similar preventive effects are also observed when apoptosis signal-regulating kinase 1, JNK1/2, or ER stress is inhibited. Cell membrane stabilizers and antioxidant supplements are also effective in prevention of diabetes-induced birth defects. Mechanistic studies have revealed important insights into our understanding the cause of diabetic embryopathy and have provided a basis for future interventions against birth defects or other pregnancy complications associated with maternal diabetes. The knowledge of a molecular pathway map identified in animal studies has created unique opportunities to identify molecular targets for therapeutic intervention.

microRNA and Wound Healing

microRNAs (miRNAs) are small noncoding RNA molecules which play pivotal roles in wound healing. The increased expression of certain genes and expression of some others represent a key component of the wound biology and are largely under the regulation of naturally occurring miRNAs. Understanding the dysregulated miRNAs in chronic wound biology will therefore enable the development of newer therapies. This chapter focuses on the miRNAs that can be potentially targeted for improving skin wound healing and the challenges in miRNA therapy, including considerations in miRNA target identification and delivery.

Metabolic pathology of autism in relation to redox metabolism

An imbalance in glutathione-dependent redox metabolism has been shown to be associated with autism spectrum disorder (ASD). Glutathione synthesis and intracellular redox balance are linked to folate and methylation metabolism, metabolic pathways that have also been shown to be abnormal in ASD. Together, these metabolic abnormalities define a distinct ASD endophenotype that is closely associated with genetic, epigenetic and mitochondrial abnormalities, as well as environmental factors related to ASD. Biomarkers that reflect these metabolic abnormalities will be discussed in the context of an ASD metabolic endophenotype that may lead to a better understanding of the pathophysiological mechanisms underlying core and associated ASD symptoms. Last, we discuss how these biomarkers have been used to guide the development of novel ASD treatments.

Vitamin A and beta-carotene concentrations in adults with HIV/AIDS on highly active antiretroviral therapy

Micronutrient deficiency is a common condition in HIV-infected individuals and may occur in all stages of the disease. The objective of this cross-sectional study was to compare the concentrations of vitamin A and beta-carotene, micronutrients related to immunity and oxidative stress, in 182 adults with HIV/AIDS, under different highly active antiretroviral therapy (HAART) regimens. Patients were divided into 3 groups according to their HAART regimen: combination of nucleoside analog reverse transcriptase inhibitors (NRTIs) and non-NRTIs; combination of NRTIs, protease inhibitors, and ritonavir; combination of NRTIs and other classes. Multiple linear regression analysis determined the effect of the treatment regimen, time of use, and compliance with the regimen, on vitamin A and beta-carotene concentrations, controlling for the following variables: gender, age, educational level, smoking, physical activity, body mass index, time of infection with HIV, presence of comorbidities, CD4(+) T lymphocyte count, total cholesterol and fractions, and triglyceride levels. There was no significant difference in vitamin A or beta-carotene concentrations in patients under the different HAART regimens. However, approximately 4% of the patients had deficient/low concentrations of vitamin A (<0.70 μmol/L), and 98% showed concentrations of beta-carotene <1.0 μmol/L. In conclusion, HIV/AIDS patients in this region will not benefit from vitamin A supplementation, independently of the HAART regimen utilized, but beta-carotene may be of importance, considering its antioxidant effect.

A review: alteration of in vitro reproduction processes by thiols -emphasis on 2-mercaptoethanol

Descriptions of organosulfurs altering biologically relevant cellular functions began some 40 years ago when murine in vitro cell mediated and humoral immune responses were shown to be dramatically enhanced by any of four xenobiotic, sulfhydryl compounds-2-mercaptoethanol (2ME), dithiothreitol (DTT), glutathione, and L-cysteine; the most effective were 2ME and DTT. These findings triggered a plethora of reports defining 2ME benefits for a multitude of immunological processes. This in turn led to investigations on 2ME alterations of (a) immune functions in other species, (b) activities of other cell-types, and (c) in vivo diseases. In addition, these early findings preceded the identification of previously undefined anticarcinogenic chemicals in specific foods as organosulfurs. Taken all together, there is little doubt that organosulfur compounds have enormous benefits for cellular functions and for a multitude of diseases. Issues of importance still to be resolved are (a) clarification of mechanisms that underlie alteration of in vitro and in vivo processes and perhaps more importantly, (b) which if any in vitro alterations are relevant for (i) alteration of in vivo diseases and (ii) identification of other diseases that might therapeutically benefit from organosulfurs. As one means to address these questions, reviews of different processes impacted by thiols could be informative. Therefore, the present review on alterations of in vitro fertilization processes by thiols (mainly 2ME, since cysteamine alterations have been reviewed) was undertaken. Alterations found to occur in medium supplemented with 2ME were enhancement, no effect, or inhibition. Parameters associated with which are discussed as they relate to postulated thiol mechanisms.

Quantitative redox biology: an approach to understand the role of reactive species in defining the cellular redox environment

Systems biology is now recognized as a needed approach to understand the dynamics of inter- and intra-cellular processes. Redox processes are at the foundation of nearly all aspects of biology. Free radicals, related oxidants, and antioxidants are central to the basic functioning of cells and tissues. They set the cellular redox environment and, therefore, are the key to regulation of biochemical pathways and networks, thereby influencing organism health. To understand how short-lived, quasi-stable species, such as superoxide, hydrogen peroxide, and nitric oxide, connect to the metabolome, proteome, lipidome, and genome we need absolute quantitative information on all redox active compounds as well as thermodynamic and kinetic information on their reactions, i.e., knowledge of the complete redoxome. Central to the state of the redoxome are the interactive details of the superoxide/peroxide formation and removal systems. Quantitative information is essential to establish the dynamic mathematical models needed to reveal the temporal evolution of biochemical pathways and networks. This new field of Quantitative Redox Biology will allow researchers to identify new targets for intervention to advance our efforts to achieve optimal human health.

Rat liver antioxidant response to iron and copper overloads

The rat liver antioxidant response to Fe and Cu overloads (0-60mg/kg) was studied. Dose- and time-responses were determined and summarized by t1/2 and C50, the time and the liver metal content for half maximal oxidative responses. Liver GSH (reduced glutathione) and GSSG (glutathione disulfide) were determined. The GSH content and the GSH/GSSG ratio markedly decreased after Fe (58-66%) and Cu (79-81%) loads, with t1/2 of 4.0 and 2.0h. The C50 were in a similar range for all the indicators (110-124μgFe/g and 40-50μgCu/g) and suggest a unique free-radical mediated process. Hydrophilic antioxidants markedly decreased after Fe and Cu (60-75%; t1/2: 4.5 and 4.0h). Lipophilic antioxidants were also decreased (30-92%; t1/2: 7.0 and 5.5h) after Fe and Cu. Superoxide dismutase (SOD) activities (Cu,Zn-SOD and Mn-SOD) and protein expression were adaptively increased after metal overloads (Cu,Zn-SOD: t1/2: 8-8.5h and Mn-SOD: t1/2: 8.5-8.0h). Catalase activity was increased after Fe (65%; t1/2: 8.5h) and decreased after Cu (26%; t1/2: 8.0h), whereas catalase expression was increased after Fe and decreased after Cu overloads. Glutathione peroxidase activity decreased after metal loads by 22-39% with a t1/2 of 4.5h and with unchanged protein expression. GSH is the main and fastest responder antioxidant in Fe and Cu overloads. The results indicate that thiol (SH) content and antioxidant enzyme activities are central to the antioxidant defense in the oxidative stress and damage after Fe and Cu overloads.

Oxidative stress and its biomarkers in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune inflammatory disease whose etiology remains largely unknown. The uncontrolled oxidative stress in SLE contributes to functional oxidative modifications of cellular protein, lipid and DNA and consequences of oxidative modification play a crucial role in immunomodulation and trigger autoimmunity. Measurements of oxidative modified protein, lipid and DNA in biological samples from SLE patients may assist in the elucidation of the pathophysiological mechanisms of the oxidative stress-related damage, the prediction of disease prognosis and the selection of adequate treatment in the early stage of disease. Application of these biomarkers in disease may indicate the early effectiveness of the therapy. This review is intended to provide an overview of various reactive oxygen species (ROS) formed during the state of disease and their biomarkers linking with disease. The first part of the review presents biochemistry and pathophysiology of ROS and antioxidant system in disease. The second part of the review discusses the recent development of oxidative stress biomarkers that relates pathogenesis in SLE patients and animal model. Finally, this review also describes the reported clinical trials of antioxidant in the disease that have evaluated the efficacy of antioxidant in the management of disease with ongoing conventional therapy.

Thiol-disulfide proteins of stallion epididymal spermatozoa

Thiol groups of cysteine residues represent redox centers involved in multiple biological functions. It has been postulated that changes in the redox status of mammalian epididymal spermatozoa contribute to the sperm maturation process. The present work shows the thiol-disulfide protein profile of stallion epididymal spermatozoa achieved by two-dimension electrophoresis and MALDI-TOF/TOF mass spectrometry of proteins labeled with a thiol-reactive fluorescent tag, monobromobimane. Our results have shown the formation of disulfide bonds in several sperm protein fractions during the epididymal maturation process. The majority of the oxidized thiol sperm proteins identified correspond to structural molecules of the flagellum (as the outer dense fiber-1 protein - ODF1), followed by glycolytic enzymes (as glyceraldehyde-3-phosphate dehydrogenase spermatogenic), antioxidant protectors (as glutathione S-transferase and phospholipid hydroperoxide glutathione peroxidase - PHGPx). The magnitude of the thiol oxidation differs between proteins, and was more drastic in polypeptides with molecular weights of up to 33kDa, identified as ODF1 and PHGPx. A kinase anchor protein, a voltage-dependent anion channel protein and a zona pellucida-binding protein were also found in the polypeptide samples that contained oxidized SH groups. These proteins may be modified or controlled by the mechanisms involved in the cysteine-redox changes, corroborating the belief that a correct degree of protein oxidation is required for the stabilization of sperm structure, protection against oxidative damage, induction of progressive sperm motility and fertilization.

Review: 2-mercaptoethanol alteration of in vitro immune functions of species other than murine

Descriptions that organosulfurs could alter biologically relevant cellular functions began some 40 years ago when cell mediated and humoral murine in vitro immune responses were reported to be dramatically enhanced by any of four xenobiotic, sulfhydryl compounds—2-mercaptoethanol (2-ME), dithiothreitol, glutathione, and l-cysteine; the most effective of the four was 2-ME. These findings triggered a plethora of reports defining 2-ME benefits for a multitude of immunological processes, primarily with murine models. This led to investigations on 2-ME alterations of (a) immune functions in other species, (b) activities of other cell-types, and (c) in situ diseases. In addition, the early findings may have been instrumental in the identification of the previously undefined anticarcinogenic chemicals in specific foods as organosulfurs. Outside the plant organosulfurs, there are no comprehensive reviews of these areas to help define mechanisms by which organosulfurs function as well as identify potential alternative uses. Therefore, the present review will focus on 2-ME alterations of in vitro immune functions in species other than murine; namely, fish, amphibian, reptile, avian, whales, dolphins, rat, hamster, rabbit, guinea pig, feline, canine, porcine, ovine, bovine, and human. Processes, some unique to a given species, were in general, enhanced and in some cases dependent upon the presence of 2-ME. The largest benefits occurred in media that were serum free, followed by those in autologous serum and then fetal bovine serum supplemented medium. Concentrations of 2-ME were generally in the low μM range, with exceptions of those for salamander (20 mM), turtles (70 mM) and dolphins (7 mM). The few studies designed to assess mechanisms found that changes induced by 2-ME were generally accompanied by alterations of reduced/oxidized glutathione cellular concentrations. The major benefit for most studies, however, was to increase the sensitivity of the culture environment, which permitted a specific process to be more easily dissected.

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2-ME altered in vitro immune functions of species other than murine.

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Benefits were found for species from fish to humans.

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Enhancement occurred in serum-free and in autologous or fetal bovine serum.

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Generally, optimal concentrations of 2-ME were in the low uM range.

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Concentration exceptions were salamander (20 mM), turtles (70 mM), and dolphins (7 mM).

Enhanced radiation response in radioresistant MCF-7 cells by targeting peroxiredoxin II

In our previous study, we identified that a protein target, peroxiredoxin II (PrxII), is overexpressed in radioresistant MCF+FIR3 breast-cancer cells and found that its expression and function is associated with breast-cancer radiation sensitivity or resistance. Small interference RNA (siRNA) targeting PrxII gene expression was able to sensitize MCF+FIR3 radioresistant breast-cancer cells to ionizing radiation. The major focus of this work was to investigate how the radiation response of MCF+FIR3 radioresistant cells was affected by the siRNA that inhibits PrxII gene expression. Our results, presented here, show that silencing PrxII gene expression increased cellular toxicity by altering cellular thiol status, inhibiting Ca(2+) efflux from the cells, and perturbing the intracellular Ca(2+) homeostasis. By combining radiotherapy and siRNA technology, we hope to develop new therapeutic strategies that may have potential to enhance the efficacy of chemotherapeutic agents due to this technology's property of targeting to specific cancer-related genes.