A fused selenium-containing protein with both GPx and SOD activities

Thyroid-disrupting effects of bisphenol S in male Wistar albino rats: Histopathological lesions, follicle cell proliferation and apoptosis, and biochemical changes

In this presented study, the aim was to investigate the toxic effects of bisphenol S (BPS), one of the bisphenol A analogues, on the thyroid glands of male Wistar albino rats. Toward this aim, the rats (n = 28) were given a vehicle (control) or BPS at 3 different doses, comprising 20, 100, and 500 mg/kg of body weight (bw) via oral gavage for 28 days. According to the results, BPS led to numerous histopathological changes in the thyroid tissue. The average proliferation index values among the thyroid follicular cells (TFCs) displayed increases in all of the BPS groups, and significant differences were observed in the BPS-20 and BPS-100 groups. The average apoptotic index values in the TFCs were increased significantly in the BPS-500 group. The serum thyroid-stimulating hormone and serum free thyroxine levels did not show significant changes after exposure to BPS; however, the serum free triiodothyronine levels displayed significant decreases in all 3 of the BPS groups. BPS was determined to cause significant increases in the antioxidant enzyme activities of catalase, superoxide dismutase, glutathione-S-transferase, glutathione peroxidase, as well as a significantly decreased content of reduced glutathione. The malondialdehyde level in the thyroid tissue was elevated significantly in the BPS-500 group. The data obtained herein revealed that BPS has thyroid-disrupting potential based on structural changes, follicle cell responses, and biochemical alterations including a decreased serum free triiodothyronine level and increased oxidative stress.

Exploring the Relationship between Antioxidant Enzymes, Oxidative Stress Markers, and Clinical Profile in Relapsing-Remitting Multiple Sclerosis

We aimed to investigate the extent of alterations in the pro/antioxidant balance in the blood of patients with relapsing-remitting multiple sclerosis (RRMS) in relation to drug-modified therapy, gender, disability score, and disease duration. 161 patients (67 men and 94 women, aged 24-69 years, median 43.0) and 29 healthy individuals (9 men and 20 women, aged 25-68 years, median 41.0) were included in the study. We measured the activity of superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) as well as the concentration of interleukin-6 (IL-6), lipid peroxidation parameters (LPO), total oxidant status (TOS), and total antioxidant capacity (TAS). The activity of SOD did not show any significant differences between patients with RRMS and the control group in our study. In contrast, significant decreased GPx activity and increased CAT activity was observed in the blood of patients with RRMS compared to the control group. Additionally, the activity of CAT was influenced by gender and the use of disease-modifying therapies. Disease-modifying therapies also affected the concentration of TOS, TAS, and LPO. Our studies indicated that enhancing GPx activity may be more beneficial to providing potential therapeutic strategies aimed at modulating antioxidant defenses to mitigate oxidative stress in this disease.

Development of phytoremediator screening strategy and exploration of Pennisetum aided chromium phytoremediation mechanisms in soil

Screening of chromium (Cr) phytoremediators (i.e., hyperaccumulator plants and accumulation plants) is essential for the phytoremediation of Cr-contaminated soils but less tackled previously. In this study, we proposed a stepwise strategy for screening Cr phytoremediators and explored tolerance mechanism of the screened species. To achieve effective screening of Cr phytoremediators, seed germination, hydroponic, and pot experiment were performed sequentially, and an improved indicator system was established accordingly. Pennisetum was selected from nine plants, with its high growth rate and Cr remediation efficiency successfully demonstrated in the field. Antioxidant enzymes (i.e., superoxide dismutase (SOD) and catalase (CAT)) and photosynthesis under Cr stress were monitored for tracking the tolerance mechanism. Results showed that the enhanced SOD and CAT contributed to the strong tolerance of Pennisetum to Cr. The SOD and CAT were positively correlated with net photosynthetic rate (Pn), resulting in a phenomenon that Cr had no significant effect on Pn of Pennisetum even at 400 mg kg^-1. The research findings helped obtain powerful Cr phytoremediators, deepen our understanding of the tolerance mechanisms associated with phytoremediation, and eventually facilitate effective Cr removal in soil.

Selenium-Enriched Soy Protein Has Antioxidant Potential via Modulation of the NRF2-HO1 Signaling Pathway

Selenium (Se)-enriched proteins are an important dietary source of Se for humans; however, only a few Se-enriched proteins have been identified. In the present study, we tested for potential antioxidant activity by Se-enriched soy protein, both in vitro and in vivo. Se-enriched soy protein isolate (S-SPI) was shown to have a higher free radical scavenging ability compared to ordinary soy protein isolate (O-SPI). Furthermore, Caco-2 cell viability was improved by S-SPI at low doses, whereas O-SPI did not. In addition, S-SPI was shown to inhibit oxidative stress via modulation of the NRF2-HO1 signaling pathway, upregulating the expression of downstream antioxidant enzymes (GPx, SOD). To further study the antioxidant capacity of S-SPI, BALB/c female mice were given oral gavages with 0.8 mL of S-SPI or O-SPI (5 g/kg/d, 20 g/kg/d and 40 g/kg/d) or saline as control. Hepatic GPx and SOD activity increased with increasing S-SPI dosage, but not with O-SPI. Taken together, our results suggest that Se-enriched soy protein has a high antioxidant ability and may be used as a dietary supplement for people with oxidative dam-age-mediated diseases.

Neuroprotective Effects of Coreopsis lanceolata Flower Extract against Oxidative Stress-Induced Apoptosis in Neuronal Cells and Mice

Coreopsis lanceolata L. is a perennial plant of the family Asteraceae, and its flower is known to contain flavonoids with various bioactivities. We evaluated the effect of Coreopsis lanceolata L. flower (CLF) extracts on H2O2-induced oxidative stress (OS) in neuronal cells and mouse neurons. The flowering part of CL was used as CLF1 (70% ethanol extract) and CLF2 (water extract), and 10 types of phenolic compounds were quantified using high-performance liquid chromatography. To evaluate the neuroprotective effects of CLF, the antioxidant activities of the extracts were measured, and the expression levels of antioxidant enzymes and proteins related to OS-induced apoptosis in neuronal cells and mouse neurons treated with the extracts were investigated. In the in vitro study, CLF ameliorated H2O2-induced oxidative stress and induced the expression of antioxidant enzymes in PC12 cells. Furthermore, CLF1 enhanced the expression of the Bcl-xL protein but reduced the expression of Bax and the cleavage of caspase-3. In the same manner, CLF1 showed neuroprotective effects against OS in vivo. Pretreatment with CLF1 (200 mg/kg) increased the Bcl-2 protein and decreased Bax compared with the 1-methyl-4-phenylpyridinium ion (MPP+)-treated C57BL/6 mice model group. Our results suggest that the protective effects of CLF1 on MPP+-induced apoptosis may be due to its anti-apoptotic activity, through regulating the expression of the Bcl-2 family. CLF1 exerts neuroprotective effects against OS-induced apoptosis in PC12 cells in a Parkinson's disease model mouse. This effect may be attributable to the upregulation of Bcl-2 protein expression, downregulation of Bax expression, and inhibition of caspase-3 activation. These data indicate that CLF may provide therapeutic value for the treatment of progressive neurodegenerative diseases.

Toxicity of different forms of antimony to rice plants: Effects on reactive oxidative species production, antioxidative systems, and uptake of essential elements

Antimonite [Sb(III)] and antimonate [Sb(V)] are known to have different toxicity to plants, but the corresponding mechanisms are not fully understood. This study was conducted to investigate reactive oxygen species (ROS), antioxidant systems, and levels of certain essential elements in response to exposure to Sb(III) and Sb(V). Results showed that exposure to Sb(V) caused oxidative stress in a rice plant (Yangdao No.6). Sb(III) was shown to be more toxic than Sb(V) as judged from a lower shoot biomass, a higher loss of essential elements, and higher production of superoxide anion free radicals (O₂^-). The toxicity of Sb(III) might partially be due to the disturbance of the O₂^- dismutation reaction, which resulted in root cell membrane damage under exposure to 20 mg L^-1 Sb(III). Sb(V) stimulated the shoot fresh weight and the shoot uptake of many essential elements. Moreover, Sb(V) and Sb(III) both stimulated the accumulation of calcium in the shoots and roots, and calcium was found to significantly correlate with the concentrations of many essential elements and with some parameters correlated to antioxidant systems, suggesting a Ca-induced regulatory mechanism. The activity of glutathione peroxidase was significantly enhanced by Sb(V) and Sb(III), suggesting a role in scavenging hydrogen peroxide. Catalase was activated by exposure to 20 mg L^-1 Sb(III) in the roots and by exposure to 20 mg L^-1 Sb(V) both in the shoots and roots. However, peroxidase was activated by exposure to 5 mg L^-1 Sb(III) in the shoots and by exposure to 5 mg L^-1 Sb(V) in the roots. This study, for the first time, showed the differences between Sb(V) and Sb(III) toxicity when looking at the antioxidant response and essential element uptake.

Erigeron annuus Protects PC12 Neuronal Cells from Oxidative Stress Induced by ROS-Mediated Apoptosis

Reactive oxygen species (ROS), associated with oxidative stress, are involved in many biological processes such as apoptosis, necrosis, and autophagy. Oxidative stress might induce neuronal damage via ROS generation, causing neurodegenerative diseases. Erigeron annuus (EA) has antioxidant properties and could protect neurons from oxidative stress. In this study, we investigated the protective effect of the aerial parts (EAA) and flowers (EAF) from EA on ROS-mediated apoptosis in pheochromocytoma 12 cells. We quantified 18 types of phenolic compounds using high-performance liquid chromatography. Pretreatment of the cells with EAA and EAF attenuated ROS generation and induced the expression of antioxidant enzymes such as superoxide dismutase 2, catalase, and glutathione peroxidase. In addition, EAF reduced the expression of apoptotic proteins such as Bax/Bcl-xL, caspase-3, and caspase-8 to a greater extent than that with EAA. These results suggested that the protective effect of EAF against oxidative stress-induced apoptosis might be due to the prevention of ROS generation mediated by oxidative enzymes.

Stronger antioxidant enzyme immunoreactivity of Populus tomentiglandulosa extract than ascorbic acid in rat liver and kidney

Objective(s):

Populus species have various pharmacological properties, including antioxidant activity. In this study, the effects of Populus tomentiglandulosa extract (PTE) on histopathology and antioxidant enzymes in the rat liver and kidney were examined.

Materials and Methods:

Sprague-Dawley rats were assigned to three groups; (1) normal diet fed group, (2) ascorbic acid-containing diet-fed group as a positive control, (3) PTE-containing diet-fed group. The histopathology in the rat liver and kidney was examined by hematoxylin and eosin staining. The effect of PTE was examined in the rat liver and kidney by immunohistochemistry for antioxidant enzymes, such as superoxide dismutases (SOD1 and SOD2), catalase (CAT), and glutathione peroxidase (GPx).

Results:

No marked histopathological alterations were observed in the liver and kidney of the PTE-containing diet-fed group. In the liver, the mean numbers of SOD1, SOD2, CAT, and GPx immunoreactive cells were significantly increased in the PTE-containing diet-fed rats, compared with those in the normal- and ascorbic acid-containing diet-fed rats. In the kidney, all SOD1, SOD2, CAT, and GPx immunoreactive structures were significantly increased in the PTE-containing diet-fed group, compared with those in the normal- and ascorbic acid-containing diet-fed groups.

Conclusion:

Results showed that PTE treatment significantly increased antioxidant enzymes in the rat liver and kidney, and we suggest that PTE might have hepato- and nephro-protective potentials against oxidative stress.

Pre-treatment with Beta Carotene Gives Protection Against Nephrotoxicity Induced by Bromobenzene via Modulation of Antioxidant System, Pro-inflammatory Cytokines and Pro-apoptotic Factors

Bromobenzene is an environmental toxin which causes hepatotoxicity, and the secondary metabolites on biotransformation cause nephrotoxicity. The objective of this study was to assess the alleviation of the nephrotoxic effect of bromobenzene by beta carotene in female Wistar albino rats. Beta carotene (10 mg/kg b.w.p.o.) was delivered orally to the rats for 9 days before bromobenzene (10 mM/kg b.w.p.o.) was intragastrically intubated. Kidney markers, antioxidant status and lipid peroxidation were evaluated. In addition, the levels of TNF-α, IL-6 and IL-1β were measured in serum and in kidney tissue homogenate using ELISA. Caspase, COX-2 and NF-κB were measured with the help of Western blotting. Histopathological analysis of the kidney was done for the control and experimental rats. Bromobenzene induction caused elevation in levels of creatinine, urea, uric acid, cytokines and lipid per oxidation along with deterioration in histological observations and antioxidant status. Pre-treatment with beta carotene significantly (*p < 0.05) normalised the levels of kidney markers and pro-inflammatory cytokines. It also reduced oxidative stress and lipid peroxidation, as shown by improved antioxidant status. The anti-apoptotic activity was evidenced by inhibition of protein expression of caspase, COX-2 and NF-κB. This significant reversal (*p < 0.05) of the above variations in comparison with the control group as noticed in the bromobenzene-administered rats demonstrates that beta carotene possesses promising nephroprotective effect through its antioxidant, anti-inflammatory and anti-apoptotic activity and therefore suggests its use as a potential therapeutic agent for protection from bromobenzene and hence environmental pollutant toxicity.

Construction of Artificial Enzymes on a Virus Surface

Combination of artificial enzyme design and self-assembly strategies leads to a novel way to construct supramolecular enzymes. To address this challenge, auxotrophic expression systems show great potential because they can introduce nonnatural catalytic groups into the subunits of protein assemblies. Among nonnatural amino acids, selenocysteine is the catalytic group of glutathione peroxidase (GPx). With the aid of computer simulation, we have incorporated selenocysteine into natural protein assemblies such as tobacco mosaic virus (TMV) and ferritin by cysteine auxotrophic technology, resulting in the conversion of TMV and ferritin into supramolecular enzymes.

Study on a 65-mer peptide mimetic enzyme with GPx and SOD dual function

Excessive reactive oxygen species (ROS) levels are harmful to the body. The peroxidase, GPx, and the superoxide dismutase, SOD, are important antioxidant enzymes for preventing ROS-induced damage. Se-CuZn-65P is an enzyme mimetic with dual GPx and SOD antioxidant function. However, currently, its production is mainly based on the cysteine auxotrophic expression technique, which is inefficient, expensive, and time consuming. In this study, we combined protein engineering and the chemical mutation method to synthesize Se-CuZn-65P. The DNA sequence encoding the 65 amino acid peptide with the desired sequence transformations to incorporate the SOD and the GPx catalytic sites was cloned and expressed in a soluble protein expression vector. The protein yield increased up to 152 mg/L, which is 10 times higher than in previous studies. The SOD and GPx activity of Se-CuZn-65P was high (1181 U/mg and 753 U/μmol, respectively). The binding constant of glutathione was 5.6 × 10⁴  L·mol^-1 , which shows that Se-CuZn-65P efficiently catalyzed hydrogen peroxide reduction by glutathione. Mitochondrial damage experiments confirmed the double protective role of the Se-CuZn-65P peptide and demonstrated functional synergy between the SOD and the GPx domains, which indicates its potential to be used in the treatment of ROS-related diseases. Our research may give a new thought to increase the yield of mimic.

Advanced Oxidation Protein Products and Carbonylated Proteins as Biomarkers of Oxidative Stress in Selected Atherosclerosis-Mediated Diseases

Objectives

The main question of this study was to evaluate the intensity of oxidative protein modification shown as advanced oxidation protein products (AOPP) and carbonylated proteins, expressed as protein carbonyl content (C=O) in abdominal aortic aneurysms (AAA), aortoiliac occlusive disease (AIOD), and chronic kidney disease (CKD).

Design and Methods

The study was carried out in a group of 35 AAA patients and 13 AIOD patients. However, CKD patients were divided into two groups: predialysis (PRE) included 50 patients or hemodialysis (HD) consisted of 34 patients. AOPP and C=O were measured using colorimetric assay kit, while C-reactive protein concentration was measured by high-sensitivity assay (hsCRP).

Results

The concentration of AOPP in both AAA and AIOD groups was higher than in PRE and HD groups according to descending order: AAA~AIOD > HD > PRE. The content of C=O was higher in the PRE group in comparison to AIOD and AAA according to the descending order: PRE~HD > AAA~AIOD.

Conclusions

AAA, AIOD, and CKD-related atherosclerosis (PRE and HD) contribute to the changes in the formation of AOPP and C=O. They may promote modification of proteins in a different way, probably due to the various factors that influence oxidative stress here.

Improvement of spatial learning and memory, cortical gyrification patterns and brain oxidative stress markers in diabetic rats treated with Ficus deltoidea leaf extract and vitexin

Despite the fact that Ficus deltoidea and vitexin played important roles in controlling hyperglycemia, an effective mitigation strategy dealing with cognitive deficit observed in diabetes, little is known about its neuroprotective effects. The study is aimed to determine changes in behavioral, gyrification patterns and brain oxidative stress markers in streptozotocin (STZ)-induced diabetic rats following F. deltoidea and vitexin treatments. Diabetic rats were treated orally with metformin, methanolic extract of F. deltoidea leaves and vitexin for eight weeks. Morris water maze (MWM) test was performed to evaluate learning and memory functions. The patterns of cortical gyrification were subsequently visualized using micro-computed tomography (micro-CT). Quantification of brain oxidative stress biomarkers, insulin, amylin as well as serum testosterone were measured using a spectrophotometer. The brain fatty acid composition was determined using gas chromatography (GC). Biochemical variation in brain was estimated using Fourier transform infrared (FT-IR) spectroscopy. Results showed that oral administration of F. deltoidea extract and vitexin to diabetic rats attenuated learning and memory impairment, along with several clusters of improved gyrification. Both treatments also caused a significant increase in the superoxide dismutase (SOD) and glutathione peroxidase (GPx) values, as well as a significant reduction of TBARS. Strikingly, improvement of cortical gyrification, spatial learning and memory are supported by serum testosterone levels, fatty acid composition of brain and FT-IR spectra.

Stimulation of gene expression and activity of antioxidant related enzyme in Sprague Dawley rat kidney induced by long-term iron toxicity

The trace elements such as iron are vital for various enzyme activities and for other cellular proteins, but iron toxicity causes the production of reactive oxygen species (ROS) that causes alterations in morphology and function of the nephron. The present study was designed to determine the effect of long-term iron overload on the renal antioxidant system and to determine any possible correlation between enzymatic and molecular levels. Our data showed that reduced glutathione (GSH) levels, which is a marker for oxidative stress, strikingly decreased with a long-term iron overload in rat kidney. While renal mRNA levels of glucose 6-phosphate dehydrogenase (G6pd), 6-phosphogluconate dehydrogenase (6pgd) and glutathione peroxidase (Gpx) were significantly affected in the presence of ferric iron, no changes were seen for glutathione reductase (Gsr) and glutathione S-transferases (Gst). While the iron affected the enzymatic activity of G6PD, GSR, GST, and GPX, it had no significant effect on 6PGD activity in the rat kidney. In conclusion, we reported here that the gene expression of G6pd, 6pgd, Gsr, Gpx, and Gst did not correlate to enzyme activity, and the actual effect of long-term iron overload on renal antioxidant system is observed at protein level. Furthermore, the influence of iron on the renal antioxidant system is different from its effect on the hepatic antioxidant system.

Tight junction proteins and oxidative stress in heavy metals-induced nephrotoxicity

Kidney is a target organ for heavy metals. They accumulate in several segments of the nephron and cause profound alterations in morphology and function. Acute intoxication frequently causes acute renal failure. The effects of chronic exposure have not been fully disclosed. In recent years increasing awareness of the consequences of their presence in the kidney has evolved. In this review we focus on the alterations induced by heavy metals on the intercellular junctions of the kidney. We describe that in addition to the proximal tubule, which has been recognized as the main site of accumulation and injury, other segments of the nephron, such as glomeruli, vessels, and distal nephron, show also deleterious effects. We also emphasize the participation of oxidative stress as a relevant component of the renal damage induced by heavy metals and the beneficial effect that some antioxidant drugs, such as vitamin A (all-trans-retinoic acid) and vitamin E (α-tocopherol), depict on the morphological and functional alterations induced by heavy metals.

Construction of GPx active centers on natural protein nanodisk/nanotube: a new way to develop artificial nanoenzyme

Construction of catalytic centers on natural protein aggregates is a challenging topic in biomaterial and biomedicine research. Here we report a novel construction of artificial nanoenzyme with glutathione peroxidase (GPx)-like function. By engineering the surface of tobacco mosaic virus (TMV) coat protein, the main catalytic components of GPx were fabricated on TMV protein monomers. Through direct self-assembly of the functionalized viral coat proteins, the multi-GPx centers were installed on these well-defined nanodisks or nanotubes. With the help of muti-selenoenzyme centers, the resulting organized nanoenzyme exhibited remarkable GPx activity, even approaching the level of natural GPx. The antioxidation study on subcell mitochondrial level demonstrated that virus-based nanoenzyme exerted excellent capacity for protecting cell from oxidative damage. This strategy represents a new way to develop artificial nanoenzymes.