Restricted glycolysis is a primary cause of the reduced growth rate of zinc-deficient yeast cells.

Zinc is required for many critical processes, including intermediary metabolism. In Saccharomyces cerevisiae, the Zap1 activator regulates the transcription of ∼80 genes in response to Zn supply. Some Zap1-regulated genes are Zn transporters that maintain Zn homeostasis, while others mediate adaptive responses that enhance fitness. One adaptive response gene encodes the 2-cysteine peroxiredoxin Tsa1, which is critical to Zn-deficient (ZnD) growth. Depending on its redox state, Tsa1 can function as a peroxidase, a protein chaperone, or a regulatory redox sensor. In a screen for possible Tsa1 regulatory targets, we identified a mutation (cdc19S492A) that partially suppressed the tsa1Δ growth defect. The cdc19S492A mutation reduced activity of its protein product, pyruvate kinase isozyme 1 (Pyk1), implicating Tsa1 in adapting glycolysis to ZnD conditions. Glycolysis requires activity of the Zn-dependent enzyme fructose-bisphosphate aldolase 1, which was substantially decreased in ZnD cells. We hypothesized that in ZnD tsa1Δ cells, the loss of a compensatory Tsa1 regulatory function causes depletion of glycolytic intermediates and restricts dependent amino acid synthesis pathways, and that the decreased activity of Pyk1S492A counteracted this depletion by slowing the irreversible conversion of phosphoenolpyruvate to pyruvate. In support of this model, supplementing ZnD tsa1Δ cells with aromatic amino acids improved their growth. Phosphoenolpyruvate supplementation, in contrast, had a much greater effect on growth rate of WT and tsa1Δ ZnD cells, indicating that inefficient glycolysis is a major factor limiting yeast growth. Surprisingly however, this restriction was not primarily due to low fructose-bisphosphate aldolase 1 activity, but instead occurs earlier in glycolysis.

Peroxiredoxins in erythrocytes: far beyond the antioxidant role.

The red blood cells (RBCs) are essential to transport oxygen (O2) and nutrients throughout the human body. Changes in the structure or functioning of the erythrocytes can lead to several deficiencies, such as hemolytic anemias, in which an increase in reactive oxidative species generation is involved in the pathophysiological process, playing a significant role in the severity of several clinical manifestations. There are important lines of defense against the damage caused by oxidizing molecules. Among the antioxidant molecules, the enzyme peroxiredoxin (Prx) has the higher decomposition power of hydrogen peroxide, especially in RBCs, standing out because of its abundance. This review aimed to present the recent findings that broke some paradigms regarding the three isoforms of Prxs found in RBC (Prx1, Prx2, and Prx6), showing that in addition to their antioxidant activity, these enzymes may have supplementary roles in transducing peroxide signals, as molecular chaperones, protecting from membrane damage, and maintenance of iron homeostasis, thus contributing to the overall survival of human RBCs, roles that seen to be disrupted in hemolytic anemia conditions.

Withaferin a Attenuates Retinal Ischemia-Reperfusion Injury via Akt-Dependent Inhibition of Oxidative Stress.

Background: Retinal ischemia-reperfusion (I/R) injury often results in intractable visual impairments. The survival of retinal capillary endothelial cells is crucial for the treatment of retinal I/R injury. How to protect retinal endothelia from damage is a challenging work. Withaferin A, a small molecule derived from plants, has antibacterial and anti-inflammatory effects and has been used for about millennia in traditional medicine. The present study aimed to investigate the potential protective effect of withaferin A on retinal I/R injury. Methods: The drug-likeness of withaferin A was evaluated by the SwissADME web tool. The potential protective effect of withaferin A on the I/R-induced injury of human retinal microvascular endothelial cells (HRMECs) was investigated using multiple approaches. RNA sequencing was performed and associated mechanistic signaling pathways were analyzed based on the Kyoto Encyclopedia of Genes and Genomes data. The analytical results of RNA sequencing data were further validated by in vitro and in vivo experiments. Results: Withaferin A reduced the I/R injury-induced apoptotic death of HRMECs in vitro with a good drug-like property. RNA sequencing and experimental validation results indicated that withaferin A increased the production of the crucial antioxidant molecules heme oxygenase 1 (HO-1) and peroxiredoxin 1 (Prdx-1) during I/R. In addition, withaferin A activated the Akt signaling pathway and increased the expression of HO-1 and Prdx-1, thereby exerting an antioxidant effect, attenuated the retinal I/R injury, and decreased the apoptosis of HRMECs. The blockade of Akt completely abolished the effects of withaferin A. Conclusions: The study identified for the first time that withaferin A can protect against the I/R-induced apoptosis of human microvascular retinal endothelial cells via increasing the production of the antioxidants Prdx-1 and HO-1. Results suggest that withaferin A is a promising drug candidate for the treatment of retinal I/R injury.

Peroxiredoxin Asp f3 Is Essential for Aspergillus fumigatus To Overcome Iron Limitation during Infection.

Aspergillus fumigatus is an important fungal pathogen that causes allergic reactions but also life-threatening infections. One of the most abundant A. fumigatus proteins is Asp f3. This peroxiredoxin is a major fungal allergen and known for its role as a virulence factor, vaccine candidate, and scavenger of reactive oxygen species. Based on the hypothesis that Asp f3 protects A. fumigatus against killing by immune cells, we investigated the susceptibility of a conditional aspf3 mutant by employing a novel assay. Surprisingly, Asp f3-depleted hyphae were killed as efficiently as the wild type by human granulocytes. However, we identified an unexpected growth defect of mutants that lack Asp f3 under low-iron conditions, which explains the avirulence of the Δaspf3 deletion mutant in a murine infection model. A. fumigatus encodes two Asp f3 homologues which we named Af3l (Asp f3-like) 1 and Af3l2. Inactivation of Af3l1, but not of Af3l2, exacerbated the growth defect of the conditional aspf3 mutant under iron limitation, which ultimately led to death of the double mutant. Inactivation of the iron acquisition repressor SreA partially compensated for loss of Asp f3 and Af3l1. However, Asp f3 was not required for maintaining iron homeostasis or siderophore biosynthesis. Instead, we show that it compensates for a loss of iron-dependent antioxidant enzymes. Iron supplementation restored the virulence of the Δaspf3 deletion mutant in a murine infection model. Our results unveil the crucial importance of Asp f3 to overcome nutritional immunity and reveal a new biological role of peroxiredoxins in adaptation to iron limitation. IMPORTANCE Asp f3 is one of the most abundant proteins in the pathogenic mold Aspergillus fumigatus. It has an enigmatic multifaceted role as a fungal allergen, virulence factor, reactive oxygen species (ROS) scavenger, and vaccine candidate. Our study provides new insights into the cellular role of this conserved peroxiredoxin. We show that the avirulence of a Δaspf3 mutant in a murine infection model is linked to a low-iron growth defect of this mutant, which we describe for the first time. Our analyses indicated that Asp f3 is not required for maintaining iron homeostasis. Instead, we found that Asp f3 compensates for a loss of iron-dependent antioxidant enzymes. Furthermore, we identified an Asp f3-like protein which is partially functionally redundant with Asp f3. We highlight an unexpected key role of Asp f3 and its partially redundant homologue Af3l1 in overcoming the host's nutritional immunity. In addition, we uncovered a new biological role of peroxiredoxins.

Guanine Nucleotide-Binding Protein G(i) Subunit Alpha 2 Exacerbates NASH Progression by Regulating Peroxiredoxin 1-Related Inflammation and Lipophagy.

BACKGROUND AND AIMS: NASH is an advanced stage of liver disease accompanied by lipid accumulation, inflammation, and liver fibrosis. Guanine nucleotide-binding protein G(i) subunit alpha-2 (GNAI2) is a member of the "inhibitory" class of α-subunits, and recent studies showed that Gnai2 deficiency is known to cause reduced weight in mice. However, the role of GNAI2 in hepatocytes, particularly in the context of liver inflammation and lipid metabolism, remains to be elucidated. Herein, we aim to ascertain the function of GNAI2 in hepatocytes and its impact on the development of NASH. APPROACH AND RESULTS: Human liver tissues were obtained from NASH patients and healthy persons to evaluate the expression and clinical relevance of GNAI2. In addition, hepatocyte-specific Gnai2-deficient mice (Gnai2hep-/- ) were fed either a Western diet supplemented with fructose in drinking water (WDF) for 16 weeks or a methionine/choline-deficient diet (MCD) for 6 weeks to investigate the regulatory role and underlying mechanism of Gnai2 in NASH. GNAI2 was significantly up-regulated in liver tissues of patients with NASH. Following feeding with WDF or MCD diets, livers from Gnai2hep-/- mice had reduced steatohepatitis with suppression of markers of inflammation and an increase in lipophagy compared to Gnai2flox/flox mice. Toll-like receptor 4 signals through nuclear factor kappa B to trigger p65-dependent transcription of Gnai2. Intriguingly, immunoprecipitation, immunofluorescence, and mass spectrometry identified peroxiredoxin 1 (PRDX1) as a binding partner of GNAI2. Moreover, the function of PRDX1 in the suppression of TNF receptor-associated factor 6 ubiquitin-ligase activity and glycerophosphodiester phosphodiesterase domain-containing 5-related phosphatidylcholine metabolism was inhibited by GNAI2. Suppression of GNAI2 combined with overexpression of PRDX1 reversed the development of steatosis and fibrosis in vivo. CONCLUSIONS: GNAI2 is a major regulator that leads to the development of NASH. Thus, inhibition of GNAI2 could be an effective therapeutic target for the treatment of NASH.

Zingiber roseum Rosc. rhizome: A rich source of hepatoprotective polyphenols.

Zingiber roseum is native to Bangladesh and widely used in folk medicine. This present study was designed to assess the ameliorative potential of Zingiber roseum rhizome extract in carbon tetrachloride (CCl4) induced hepatotoxicity in mice model. Seven phenolic compounds were identified and quantified by HPLC analysis in the plant extract, including quercetin, myricetin, catechin hydrate, trans-ferulic acid, trans-cinnamic acid, (-) epicatechin, and rosmarinic acid. Hepatotoxicity was induced by administrating a single intraperitoneal injection of CCl4 (10 mL/kg) on 7th day of treatment. The results revealed that plant extract at all doses (100, 200 and 400 mg/kg) significantly reduced (p < 0.05) the elevated serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) concentrations, and these effects were comparable to that of standard drug silymarin. Histopathological examination also revealed the evidence of recovery from CCL4 induced cellular damage when pretreated with Z. roseum rhizome extract. The in-vivo hepatoprotective effects were further investigated by the in-silico study of the aforementioned compounds with liver-protective enzymes such as superoxide dismutase (SOD), peroxiredoxin, and catalase. The strong binding affinities (ranging from -7.3359 to -9.111 KCal/mol) between the phenolic compounds (except trans-cinnamic acid) and oxidative stress enzymes inhibit ROS production during metabolism. The compounds were also found non-toxic in computational prediction, and a series of biological activities like antioxidant, anticarcinogen, cardio-protectant, hepato-protectant have been detected.

Peroxiredoxin 2 oxidation reveals hydrogen peroxide generation within erythrocytes during high-dose vitamin C administration.

Intravenous infusion of high dose (>10 g) vitamin C (IVC) is a common alternative cancer therapy. IVC results in millimolar levels of circulating ascorbate, which is proposed to generate cytotoxic quantities of H2O2 in the presence of transition metal ions. In this study we report on the in vitro and in vivo effects of millimolar ascorbate on erythrocytes. Addition of ascorbate to whole blood increased erythrocyte intracellular ascorbate approximately 35-fold. Within 10 min of ascorbate addition, we detected increased oxidation of erythrocyte peroxiredoxin 2 (Prx2), a major thiol antioxidant protein and a sensitive marker of H2O2 production. Up to 50% of Prx2 was present in the oxidised form after 60 min. The presence of extracellular catalase, removal of plasma or the addition of a metal chelator did not prevent ascorbate-induced Prx2 oxidation, suggesting that the H2O2 responsible for Prx2 oxidation was generated within the erythrocyte. Ascorbate is known to increase the rate of haemoglobin autoxidation and H2O2 production. Through spectral monitoring of oxidised haemoglobin we estimated a generation rate of 15 µM H2O2/min inside erythrocytes. We also investigated changes in erythrocyte ascorbate concentration and Prx2 oxidation following IVC infusion in a cohort of patients with cancer. Plasma ascorbate levels ranged from 7.8 to 35 mM immediately post infusion, while erythrocyte ascorbate levels reached 1.5-3.4 mM 4 h after beginning infusion. Transient oxidation of erythrocyte Prx2 was observed. We conclude that erythrocytes accumulate ascorbate during IVC infusion, providing a significant reservoir of ascorbate, and this ascorbate increases H2O2 generation within the cells. The consequence of increased erythrocyte Prx2 oxidation warrants further investigation.

Effect of Shenkang on renal fibrosis and activation of renal interstitial fibroblasts through the JAK2/STAT3 pathway.

BACKGROUND: Activation of renal fibroblasts is a critical mechanism in the process of renal fibrosis. As a commonly used herbal formula, Shenkang (SK) has been found to attenuate renal fibrosis and renal parenchyma destruction. However, the effect of SK on renal fibroblast activation in unilateral ureteral obstruction (UUO) mice and its molecular mechanism remain undetermined. The present study was performed to elucidate the effect of SK on renal fibroblast activation and renal fibrosis, as well as the potential underlying mechanism, in both NRK-49F cells and UUO mice. METHODS: NRK-49F cells were stimulated with 10 ng/ml TGF-ß1 for 48 h. After SK treatment, the CCK-8 method was used to evaluate cell viability. Thirty-six C57BL/6 mice were randomly divided into the sham group, UUO group, angiotensin receptor blocker (ARB) group, and SK high-, moderate- and low-dose groups. UUO was induced in mice except those in the sham group. Drugs were administered 1 day later. On the 13th day, the fractional anisotropy (FA) value was determined by MRI to evaluate the degree of renal fibrosis. After 14 days, serum indexes were assessed. Hematoxylin and eosin (HE) and Sirius red staining were used to observe pathological morphology and the degree of fibrosis of the affected kidney. Western blotting and PCR were used to assess the expression of related molecules in both cells and animals at the protein and gene levels. RESULTS: Our results showed that SK reduced extracellular matrix (ECM) and α-smooth muscle actin (α-SMA) expression both in vitro and in vivo and attenuated renal fibrosis and the pathological lesion degree after UUO, suppressing JAK2/STAT3 activation. Furthermore, we found that SK regulated the JAK2/STAT3 pathway regulators peroxiredoxin 5 (Prdx5) in vitro and suppressor of cytokine signaling protein 1 (SOCS1) and SOCS3 in vivo. CONCLUSIONS: These results indicated that SK inhibited fibroblast activation by regulating the JAK2/STAT3 pathway, which may be a mechanism underlying its protective action in renal fibrosis.

Anemarrhena asphodeloides modulates gut microbiota and restores pancreatic function in diabetic rats.

Anemarrhena asphodeloides is an herb widely used to treat symptoms associated with diabetes in traditional Chinese medicine. However, its key components and metabolites have low bioavailability and poor host absorption. To clarify the anti-diabetic mechanism of A. asphodeloides extract (AAE), we examined the anti-diabetic effects of AAE in rats with diabetes induced by a high-fat diet and streptozotocin. Faeces levels of the main components and metabolites of AAE were significantly higher than levels in plasma, which indicated that gut microbiota might play important roles in its anti-diabetic effect. Microbiological studies showed that unabsorbed components increased the diversity of the gut microbiota, enriched potentially beneficial bacteria, and suppressed potentially harmful bacteria. In vitro studies showed that AAE promoted the proliferation of Blautia coccoides, a bacterium with positive implication for diabetes, in a dose-dependent manner. AAE also promoted pancreatic cell regeneration and restored the function of pancreatic islet cells via peroxiredoxin 4 overexpression. Overall, these results suggest that AAE alleviates diabetes via modulating gut microbiota and protein expression.

[Guilingji Capsules reduce 900 MHz collphone electromagnetic radiation-induced testicular oxidative damage and downregulate Prdx2 protein expression in the rat testis].

OBJECTIVE: To investigate the relationship of electromagnetic radiation (EMR) from 900 MHz cellphone frequency with testicular oxidative damage and its influence on the Prdx2 protein expression in the rat testis, and to explore the mechanism of Guilingji Capsules (GC) alleviating oxidative damage to the testis tissue. METHODS: Fifty healthy SD male rats were randomly divided into five groups of equal number, sham-EMR, 4-h EMR, 8-h EMR, 4-h EMR+GC and 8-h EMR+GC and exposed to 900 MHz EMR (370 µW/cm2) for 0, 4 or 8 hours daily for 15 successive days. The rats of the latter two groups were treated intragastrically with GC suspension and those of the first three groups with pure water after exposure to EMR each day. After 15 days of exposure and treatment, all the rats were sacrificed and their testis tissue collected for observation of the histomorphological and ultrastructural changes by HE staining and transmission electron microscopy, measurement of the levels of serum glutathione (GSH), superoxide dismutase (SOD) and malondialdehyde (MDA) with thiobarbiuric acid and determination of the Prdx2 protein expression by immunohistochemistry and Western blot. RESULTS: Compared with the rats in the sham-EMR group, those in the 4-h and 8-h EMR groups showed different degrees of histomorphological and ultrastructural changes in the testis tissue, significantly decreased levels of GSH (ï¼»80.62 ± 10.99ï¼½ vs ï¼»69.58 ± 4.18ï¼½ and ï¼»66.17 ± 8.45ï¼½ mg/L, P < 0.05) and SOD (ï¼»172.29 ± 10.98ï¼½ vs ï¼»158.92 ± 6.46ï¼½ and ï¼»148.91 ± 8.60ï¼½ U/ml, P < 0.05) and increased level of MDA (ï¼»7.51 ± 1.73ï¼½ vs ï¼»9.84 ± 1.03ï¼½ and ï¼»11.22 ± 2.13ï¼½ umol/ml, P < 0.05), even more significantly in the 8-h than in the 4-h EMR group (P < 0.05). In comparison with the sham-EMR group, the expression of the Prdx2 protein was markedly downregulated in the 4-h and 8-h EMR groups (0.56 ± 0.03 vs 0.49 ± 0.03, 0.21 ± 0.01, P < 0.05), but again upregulated in the 4-h and 8-h EMR+GC groups (0.55±0.03 and 0.37±0.04) (P < 0.05). CONCLUSIONS: Electromagnetic radiation from cellphones can cause ultrastructural damage to the testis tissue of male rats, while Guilingji Capsules can alleviate it, presumably by upregulating the Prdx2 protein expression in the testis tissue and reducing testicular oxidative damage.

Updates on the epidemiology, pathogenesis, diagnosis, and management of postinfectious irritable bowel syndrome.

PURPOSE OF REVIEW: With its impact on quality of life and increasing awareness, postinfectious irritable bowel syndrome (PI-IBS) is now gaining attention as one of the major health problems commonly encountered in gastrointestinal practice. Literature investigating the various pathogenic mechanisms involved is rapidly emerging. The objective of the current review is to provide an update on recent evidence published in the past 2 years describing advances in our understanding of the epidemiology, pathogenesis, diagnosis, and treatment of PI-IBS. RECENT FINDINGS: Significant proportion of research in the recent past was preclinical in nature. Epidemiological studies continue to highlight the risk of IBS after infection, with recent studies documenting postprotozoal effects. Advances in pathogenic mechanisms included clinical studies, which documented micro-RNA down-regulation and Peroxiredoxin-1 up-regulation in colonic mucosa of PI-IBS patients. Protease-activated receptor-2 (PAR-2) activation in PI-IBS mice models resulted in increase in epithelial permeability, mucosal inflammation, visceral hypersensitivity. Moxibustion and rifamycin reduced intestinal inflammation by inhibiting cytokine and chemokine release via different mechanisms. Miltefosine reduced mast cell degranulation and TRPV1 activation, thereby reducing visceral hypersensitivity. SUMMARY: At present, generalization of limited diagnostic and therapeutic strategies across a heterogeneous prevalent patient population impedes the ability to provide effective personalized care in PI-IBS. Further development in pathogenesis discovery, diagnostic tool development are needed in order to design well tolerated and effective therapies that guide treatments based on distinct pathways of disease.

Galectin-3 inhibition attenuates doxorubicin-induced cardiac dysfunction by upregulating the expression of peroxiredoxin-4.

Doxorubicin (DOX) is a highly efficient chemotherapeutic drug limited by its cardiotoxicity. Galectin-3 (Gal-3) overexpression is associated with several cardiovascular diseases. In this study, the in vivo models of DOX-treated rats and the in vitro model of DOX-treated H9C2 cells were used. DOX induced cardiac injury and dysfunction accompanied with the upregulation of Gal-3 at the end of the experiment, while inhibition of Gal-3 with modified citrus pectin (MCP) exhibited a dramatic improvement in cardiac function of the DOX-treated rats, as manifested by increased left ventricular systolic pressure and ±dp/dtmax and decreased left ventricular end-diastolic pressure. The plasma levels of myocardial injury markers such as lactate dehydrogenase, creatine kinase, creatine kinase-MB, and cardiac troponin I were decreased after MCP treatment. In parallel, MCP attenuated myocardial tissue markers of oxidative stress such as hydrogen peroxide and malondialdehyde restored the activities of superoxide dismutase, catalase, and glutathione peroxidase and upregulated antioxidant peroxiredoxin-4 (Prx-4). To further verify the role of Prx-4, it was downregulated by siRNA-mediated knockdown in H9C2 cells. MCP could not reverse DOX-induced oxidative stress in Prx-4-knock-down cells. In conclusion, Gal-3 mediated DOX-induced cardiotoxicity and Gal-3 inhibition attenuated DOX-induced cardiac dysfunction by upregulating the expression of Prx-4 to reduce myocardial oxidative stress.

Protective effect of quercetin in combination with caloric restriction against oxidative stress-induced cell death of Saccharomyces cerevisiae cells.

Impairment of antioxidant enzymes activities has been well reported in several human diseases. Effective anti-ageing strategies involving antioxidant supplementation and/or caloric restriction (CR) are receiving a great attention to mitigate free radical-mediated oxidative damage in several disease conditions to improve active longevity. Therefore, in this work, we have evaluated the protective effect of quercetin under non restriction (NR) and CR conditions on the sensitivity of Saccharomyces cerevisiae mutant strains (sod1∆, sod2∆, cta1∆, ctt1∆, tsa1∆ and glr1∆) deficient in antioxidant defence systems (superoxide dismutase, catalase, thioredoxin peroxidase and glutathione reductase) against H2 O2 -induced oxidative stress. Our results demonstrate that quercetin in combination with CR has strongly reduced the H2 O2 -mediated stress in the yeast mutant cells compared to NR conditions. Furthermore, we show that quercetin in combination with CR enhanced the percentage viability of yeast cells during chronological ageing. Our research findings suggest that antioxidant supplementation in combination with CR might have potent beneficial effects than individual therapies against free radical-mediated oxidative stress. SIGNIFICANCE AND IMPACT OF THE STUDY: Oxidative stress results from an imbalance between free radicals and antioxidant defense systems in our body. Supplementation with exogenous antioxidants is necessary to neutralize the free radical mediated damage. Polyphenols are a group of naturally occurring plant compounds with strong free radical-scavenging activity and exhibits potent anti-aging property by mitigating oxidative stress. On the other hand, caloric restriction (CR) has been reported to be a popular leading anti-aging approach to ameliorate age-associate macromolecular damages in various chronic human diseases. Evaluation of protective effects of antioxidant supplementation in combination with CR against free radical mediated oxidative stress is pivotal for the development of novel anti-aging strategies to improve active longevity.

Guilingji Capsules reduce 900 MHz collphone electromagnetic radiation-induced testicular oxidative damage and downregulate Prdx2 protein expression in the rat testis / 中华男科学杂志

Objective@#To investigate the relationship of electromagnetic radiation (EMR) from 900 MHz cellphone frequency with testicular oxidative damage and its influence on the Prdx2 protein expression in the rat testis, and to explore the mechanism of Guilingji Capsules (GC) alleviating oxidative damage to the testis tissue.@*METHODS@#Fifty healthy SD male rats were randomly divided into five groups of equal number, sham-EMR, 4-h EMR, 8-h EMR, 4-h EMR+GC and 8-h EMR+GC and exposed to 900 MHz EMR (370 μW/cm2) for 0, 4 or 8 hours daily for 15 successive days. The rats of the latter two groups were treated intragastrically with GC suspension and those of the first three groups with pure water after exposure to EMR each day. After 15 days of exposure and treatment, all the rats were sacrificed and their testis tissue collected for observation of the histomorphological and ultrastructural changes by HE staining and transmission electron microscopy, measurement of the levels of serum glutathione (GSH), superoxide dismutase (SOD) and malondialdehyde (MDA) with thiobarbiuric acid and determination of the Prdx2 protein expression by immunohistochemistry and Western blot.@*RESULTS@#Compared with the rats in the sham-EMR group, those in the 4-h and 8-h EMR groups showed different degrees of histomorphological and ultrastructural changes in the testis tissue, significantly decreased levels of GSH (［80.62 ± 10.99］ vs ［69.58 ± 4.18］ and ［66.17 ± 8.45］ mg/L, P < 0.05) and SOD (［172.29 ± 10.98］ vs ［158.92 ± 6.46］ and ［148.91 ± 8.60］ U/ml, P < 0.05) and increased level of MDA (［7.51 ± 1.73］ vs ［9.84 ± 1.03］ and ［11.22 ± 2.13］ umol/ml, P < 0.05), even more significantly in the 8-h than in the 4-h EMR group (P < 0.05). In comparison with the sham-EMR group, the expression of the Prdx2 protein was markedly downregulated in the 4-h and 8-h EMR groups (0.56 ± 0.03 vs 0.49 ± 0.03, 0.21 ± 0.01, P < 0.05), but again upregulated in the 4-h and 8-h EMR+GC groups (0.55±0.03 and 0.37±0.04) (P < 0.05).@*CONCLUSIONS@#Electromagnetic radiation from cellphones can cause ultrastructural damage to the testis tissue of male rats, while Guilingji Capsules can alleviate it, presumably by upregulating the Prdx2 protein expression in the testis tissue and reducing testicular oxidative damage.

Shikonin-induced Apoptosis of Colon Cancer Cells Is Reduced by Peroxiredoxin V Expression.

BACKGROUND/AIM: Colon cancer is the second most common deadliest malignancy in the world and better understanding of its underlying mechanisms is needed to improve clinical management. Natural plant extracts are gaining attention in the development of new therapeutic strategies against various cancer types. Shikonin is a naturally extracted naphthoquinone pigment with effects against cancer, including colon cancer. MATERIALS AND METHODS: In this study, we conducted a series of in vitro experiments to show the effects of Shikonin on colon cancer cell apoptosis. A colon cancer cell line with overexpression of peroxiredoxin V (PrxV) was constructed and the relationship of PrxV expression with Shikonin-induced cell apoptosis was investigated. RESULTS: Shikonin induced colon cancer cell apoptosis via regulation of mammalian target of rapamycin signaling. Shikonin-induced cell apoptosis was abrogated by overexpression of PrxV. CONCLUSION: According to the results obtained in this study, targeting PrxV may provide new insight for the successful management of colon cancer by inducing cell apoptosis.

Variability in the redox status of plant 2-Cys peroxiredoxins in relation to species and light cycle.

Plant 2-Cys peroxiredoxins (2-CysPRXs) are abundant plastidial thiol-peroxidases involved in key signaling processes such as photosynthesis deactivation at night. Their functions rely on the redox status of their two cysteines and on the enzyme quaternary structure, knowledge of which remains poor in plant cells. Using ex vivo and biochemical approaches, we thoroughly characterized the 2-CysPRX dimer/monomer distribution, hyperoxidation level, and thiol content in Arabidopsis, barley, and potato in relation to the light cycle. Our data reveal that the enzyme hyperoxidization level and its distribution as a dimer and monomer vary through the light cycle in a species-dependent manner. A differential susceptibility to hyperoxidation was observed for the two Arabidopsis 2-CysPRX isoforms and among the proteins of the three species, and was associated to sequence variation in hyperoxidation resistance motifs. Alkylation experiments indicate that only a minor fraction of the 2-CysPRX pool carries one free thiol in the three species, and that this content does not change during the light period. We conclude that most plastidial 2-CysPRX forms are oxidized and propose that there is a species-dependent variability in their functions since dimer and hyperoxidized forms fulfill distinct roles regarding direct oxidation of partners and signal transmission.

Compound kushen injection suppresses human acute myeloid leukaemia by regulating the Prdxs/ROS/Trx1 signalling pathway.

BACKGROUND: The increase in the levels of reactive oxygen species (ROS) in acute myeloid leukemia (AML) patients has been previously described; thus, it is important to regulate ROS levels in AML. METHODS: Flow cytometry were used to assess the in vitro effect of compound kushen injection (CKI). Quantitative proteomics were used to analyse the mechanism. The AML patient-derived xenograft (PDX) model were used to evaluate the in vivo effect of CKI. RESULTS: We found that intracellular ROS levels in AML cells were decreased, the antioxidant capacity were increased when treated with CKI. CKI inhibited the proliferation of AML cells and enhanced the cytotoxicity of AML cells, which has few toxic effects on haematopoietic stem cells (HSCs) and T cells. At the single-cell level, individual AML cells died gradually by CKI treatment on optofluidic chips. CKI promoted apoptosis and arrested cell cycle at G1/G0 phase in U937 cells. Furthermore, higher peroxiredoxin-3 (Prdx3) expression levels were identified in CKI-treated U937 cells through quantitative proteomics detection. Mechanically, the expression of Prdx3 and peroxiredoxin-2 (Prdx2) was up-regulated in CKI-treated AML cells, while thioredoxin 1 (Trx1) was reduced. Laser confocal microscopy showed that the proteins Prdx2 could be Interacted with Trx1 by CKI treatment. In vivo, the survival was longer and the disease was partially alleviated by decreased CD45+ immunophenotyping in peripheral blood in the CKI-treated group in the AML PDX model. CONCLUSIONS: Antioxidant CKI possess better clinical application against AML through the Prdxs/ROS/Trx1 signalling pathway.

Targeting Peroxiredoxin 1 by a Curcumin Analogue, AI-44, Inhibits NLRP3 Inflammasome Activation and Attenuates Lipopolysaccharide-Induced Sepsis in Mice.

Aberrant activation of the NLRP3 inflammasome contributes to the onset and progression of various inflammatory diseases, making it a highly desirable drug target. In this study, we screened a series of small compounds with anti-inflammatory activities and identified a novel NLRP3 inflammasome inhibitor, AI-44, a curcumin analogue that selectively inhibited signal 2 but not signal 1 of NLRP3 inflammasome activation. We demonstrated that AI-44 bound to peroxiredoxin 1 (PRDX1) and promoted the interaction of PRDX1 with pro-Caspase-1 (CASP1), which led to the suppression of association of pro-CASP1 and ASC. Consequently, the assembly of the NLRP3 inflammasome was interrupted, and the activation of CASP1 was inhibited. Knockdown of PRDX1 significantly abrogated the inhibitory effect of AI-44 on the NLRP3 inflammasome. Importantly, AI-44 alleviated LPS-induced endotoxemia in mice via suppressing NLRP3 inflammasome activation. Taken together, our work highlighted PRDX1 as a negative regulator of NLRP3 inflammasome activation and suggested AI-44 as a promising candidate compound for the treatment of sepsis or other NLRP3 inflammasome-driven diseases.

Melatonin alleviates low-sulfur stress by promoting sulfur homeostasis in tomato plants.

Despite involvement of melatonin (MT) in plant growth and stress tolerance, its role in sulfur (S) acquisition and assimilation remains unclear. Here we report that low-S conditions cause serious growth inhibition by reducing chlorophyll content, photosynthesis and biomass accumulation. S deficiency evoked oxidative stress leading to the cell structural alterations and DNA damage. In contrast, MT supplementation to the S-deprived plants resulted in a significant diminution in reactive oxygen species (ROS) accumulation, thereby mitigating S deficiency-induced damages to cellular macromolecules and ultrastructures. Moreover, MT promoted S uptake and assimilation by regulating the expression of genes encoding enzymes involved in S transport and metabolism. MT also protected cells from ROS-induced damage by regulating 2-cysteine peroxiredoxin and biosynthesis of S-compounds. These results provide strong evidence that MT can enhance plant tolerance to low-S-induced stress by improving S uptake, metabolism and redox homeostasis, and thus advocating beneficial effects of MT on increasing the sulfur utilization efficiency.

Biomarkers of selenium status and antioxidant effect in workers occupationally exposed to mercury.

The present observation based research was designed to evaluate the influence of occupational human exposure to metallic mercury (Hg°) vapor on the biomarkers of selenium status involved in the antioxidant defense system. For this purpose we determined Hg and selenium (Se) concentrations in body fluids, the markers of antioxidant effect measured as an activity of Se-dependent enzymes (red blood cell and plasma glutathione peroxidase: GPx1-RBC and GPx3-P), concentration of selenoprotein P in the plasma (SeP-P) and total antioxidant activity in the plasma (TAA-P) in 131 male workers from a chloralkali plant exposed to Hg° and 67 non-exposed males (control group). The mRNA expression levels of glutathione peroxidases (GPX1, GPX3), selenoprotein P (SEPP1), thioredoxin reductase 1 (TRXR1), thioredoxin 1 (TRX1), peroxiredoxins (PRDX1, PRDX2) were also examined in the leukocytes of peripheral blood. Hg concentration in the blood (Hg-B) and urine (Hg-U) samples was determined using the thermal decomposition amalgamation/atomic absorption spectrometry (TDA-AAS) method and Se concentrations in plasma (Se-P) and urine (Se-U) using the inductively coupled plasma mass spectrometry (ICP-MS) method. Activities of GPx1-RBC, GPx3-P and TAA-P were determined using the kinetic and spectrophotometric method, respectively. Gene expression analysis was performed using the quantitative Real-Time PCR. The results showed significant higher Hg levels among the Hg°-exposed workers in comparison to control group (12-times higher median for Hg-B and almost 74-times higher median for Hg-U concentration in chloralkali workers). Se-P was also significantly higher (Me (median): 82.85 µg/L (IQR (interquartile range) 72.03-90.28 µg/L) for chloralkali workers vs. Me: 72.74 µg/L (IQR 66.25-80.14 µg/L) for control group; p = 0.0001) but interestingly correlated inversely with Hg-U in chloralkali workers suggesting depletion of the Se protection among the workers with the highest Hg-U concentration. The mRNA level for GPX1, PRXD1 were markedly but significantly higher in the workers compared to the control group. Moreover, concentrations of Hg-B and Hg-U among the workers were significantly positively correlated with the levels of selenoprotein P at both the mRNA and selenoprotein levels. In the multivariate model, after adjusting to cofounders (dental amalgam fillings, age, BMI, job seniority time, smoking), we confirmed that Hg-U concentration was inversely correlated with genes expression of TRXR1. This is the first comprehensive assessment of the impact of occupational exposure of workers to Hg° at both the mRNA and selenoprotein levels, with investigation of fish intake obtained by means of a questionnaire. These findings suggest that exposure to Hg° alters gene expression of the antioxidant enzymes and the level of Se-containing selenoproteins.