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Fasciolosis caused by the liver flukes Fasciola hepatica and Fasciola gigantica is one of the most important neglected parasitic diseases of humans and animals. The ability of the parasites to infect and multiply in their intermediate snail hosts, and their adaptation to a wide variety of mammalian definitive hosts contribute to their high transmissibility and distribution. Within the mammalian host, the trauma caused by the immature flukes burrowing through the liver parenchyma is associated with most of the pathogenesis. Similarly, the feeding activity and the physical presence of large flukes in the bile ducts can lead to anaemia, inflammation, obstruction and cholangitis. The high frequency of non-synonymous polymorphisms found in Fasciola spp. genes allows for adaptation and invasion of a broad range of hosts. This is also facilitated by parasite's excretory-secretory (ES) molecules that mediate physiological changes that allows their establishment within the host. ES contains cathepsin peptidases that aid parasite invasion by degrading collagen and fibronectin. In the bile ducts, cathepsin-L is critical to haemoglobin digestion during feeding activities. Other molecules (peroxiredoxin, cathepsin-L and Kunitz-type inhibitor) stimulate a strong immune response polarised towards a Treg/Th2 phenotype that favours fluke's survival. Helminth defence molecule, fatty acid binding proteins, Fasciola-specific glycans and miRNAs modulate host pro-inflammatory responses, while antioxidant scavenger enzymes work in an orchestrated way to deter host oxidant-mediated damage. Combining these strategies Fasciola spp. survive for decades within their mammalian host, where they reproduce and spread to become one of the most widespread zoonotic worm parasites in the world.

The review of the literature presents current data on the role of NOX proteins in the physiology of the lungs and in the development of respiratory diseases. The value of the transcription factor NRF2, superoxide dismutase, catalase, glutathione system, glutaredoxin, thioredoxin, peroxiredoxin in the development of respiratory diseases was shown. Hereditary di­seases associated with generators of activated oxygen-contai-ning metabolites and components of the antioxidant system are presented. The main markers of oxidative stress and the process of inflammation in the respiratory tract are described.

Objective: to investigate the role of peroxiredoxin 6 (PRX6) in preserving the morphofunctional state of ischemic isolated kidney during perfusion.Materials and methods. The model of an isolated perfused rat kidney was used. Ischemia time was 5 and 20 minutes, perfusion was 50 minutes. To evaluate the effectiveness of PRX6 at different ischemia times, we used the conventional criteria of kidney function and histological methods.Results. During short warm ischemia times, exogenous PRX6 improves the morphofunctional state of an isolated kidney during perfusion. During this period, the main criteria for functioning of the isolated ischemic kidney reach acceptable values, renal parenchyma is without severe damage. By the end of perfusion, there was an increase in urine flow rate, glomerular filtration rate, fractional glucose reabsorption, urine urea concentration and proportion of primary urine from 1.5 to 2 times compared with the control lesion. At 20-minute ischemia, the isolated kidney can be recognized as non-viable according to the functioning criteria; the positive effect of PRX6 is leveled.Conclusion. The use of recombinant peroxiredoxin 6 for preserving the morphofunctional state of isolated kidneys can be an effective approach in preventing ischemia–reperfusion injury.

Yajun Shen,1 Haoyue Xu,2 Lingyu Li,1 Yunping Lu,1 Min Zhang,1 Xin Huang,2 Xiaofei Tang1 1Beijing Institute of Dental Research, Beijing Key Laboratory, Beijing Stomatological Hospital & School of Stomatology, Capital Medical University, Beijing, 100050, People’s Republic of China; 2Department of Oral and Maxillofacial Surgery, Beijing Stomatological Hospital & School of Stomatology, Capital Medical University, Beijing, 100050, People’s Republic of ChinaCorrespondence: Xiaofei TangDivision of Oral Pathology, Beijing Institute of Dental Research, Beijing Stomatological Hospital & School of Stomatology, Capital Medical University, No. 4 Tiantanxili, Dongcheng District, Beijing, 100050, People’s Republic of ChinaTel +86 01057099311Fax +86 01057099310Email xftang10@ccmu.edu.cnXin HuangDepartment of Oral and Maxillofacial Surgery, Beijing Stomatological Hospital & School of Stomatology, Capital Medical University, No. 4 Tiantan Xili, Dongcheng District, Beijing, 100050, People’s Republic of ChinaEmail huangxin@ccmu.edu.cnPurpose: The role of the peroxiredoxin (PRDX) family in oral squamous cell carcinoma (OSCC) remains unclear. This study aimed to investigate the expression of PRDXs and their effects on the prognosis in OSCC.Methods: The expression of PRDXs and their effects on prognosis were analysed in 216 OSCC samples from The Cancer Genome Atlas (TCGA) database. OSCC tissues and adjacent noncancerous tissues (ANTs) were obtained from 68 clinical patients. Quantitative real-time (qRT)-PCR, Western blot, and immunohistochemical (IHC) staining were used to verify the relationship between the expression level of PRDX1 and different clinical features. Gene set enrichment analysis (GSEA) was used to examine the molecular mechanism of PRDX1 in OSCC.Results: PRDX1 was found to be the only gene in PRDX family that highly expressed in OSCC samples and affected the prognosis of patients with OSCC. PRDX1 expression was significantly related to tumor stage, lymphatic metastasis, and pathological grade. A nomogram consisting of tumor stage, N stage, and PRDX1 level was constructed. GSEA showed that high expression of PRDX1 involved many cancer-related molecular functions and signaling pathways.Conclusion: PRDX1 may play an important role in the occurrence and development of OSCC, and may be a potential new target for OSCC treatment.Keywords: peroxiredoxin 1, oral squamous cell carcinoma, lymph node metastasis, prognosis, nomogram

Owing to its lipophilic nature, cypermethrin makes entry into the brain through the blood-brain barrier and causes severe damage to the nigrostriatal dopaminergic neurons after prolonged exposure. Following substantial accrual in the brain, cypermethrin induces the abnormal expression and accumulation of α-synuclein. Besides, cytochrome P450 2E1 (CYP2E1) causes free radical generation leading to lipid peroxidation in toxicant-induced parkinsonism. Conversely, 4-hydroxynonenal (4-HNE), a byproduct of lipid peroxidation, is known to contribute to neuronal damage. The current investigation aimed to explicate the participation of endogenous redox-sensitive proteins in cypermethrin-induced cellular and animal models of parkinsonism. The qualitative and quantitative expressions of selected redox-sensitive proteins were evaluated employing the standard procedures. Cypermethrin reduced the expression of peroxiredoxin 3 (Prx3), thioredoxin 2 (Trx2), and protein deglycase-1 (DJ-1). Knocking down of Prx3, Trx2, or DJ-1 further reduced the level of expression in the cypermethrin-treated group. Reduction in the expression of Prx3, Trx2, or DJ-1 was found to be associated with overexpression of α-synuclein and 4-HNE modification of proteins. Besides, cypermethrin increased the expression of CYP2E1, which was not altered after Prx3 or Trx2 knockdown. However, knocking down the DJ-1 augmented the level of CYP2E1 both in the cypermethrin-treated group and its respective control. The outcomes of the study demonstrate that cypermethrin reduces the level of Prx3, Trx2, and DJ-1 proteins. While the reduction in the expression of selected redox-sensitive proteins leads to α-synuclein overexpression and 4-HNE modification of proteins, DJ-1 attenuation is also linked with increased CYP2E1 expression, which in turn could lead to oxidative stress-mediated neuronal damage.

To explore gene expression and serum profile of selected antioxidant markers during periparturient period in dromedary camels, blood samples were collected from sixty apparently healthy pregnant female at − 14, 0, and + 14 days of expected date of delivery. Superoxide dismutase1 (SOD1), superoxide dismutase 3 (SOD3), catalase (CAT), peroxiredoxin 2 (PRDX2), peroxiredoxin 3 (PRDX3), peroxiredoxin 4 (PRDX4), peroxiredoxin 6 (PRDX6), glutathione peroxidase (GPX), and alkyl hydroperoxide reductase/thiol-specific antioxidant (AhpC/TSA) markers showed upregulations at (− 14) and (+ 14) compared to their values at calving. A significant upregulation of oxidative stress-responsive kinase 1 (OXSR1), stress-associated endoplasmic reticulum proteins (SERP2), and stress-induced phosphoprotein (STIP1) was also reported at (− 14) compared to their corresponding values at calving and (+ 14). At (− 14), serum GSH levels were low, and increased gradually until early lactation. Total antioxidant capacity (TAC) concentrations were low at (− 14) and at parturition, and the peak values were observed at (+ 14), whereas an opposite trend was noted for Malondialdehyde (MDA) levels. SOD activity was lower at (0) and (+ 14) compared to at (− 14). Glutathione peroxidase (GSH-Px) was also low at (0) and (+ 14) days postpartum compared to that at (− 14). Linear discriminant analysis (LDA) showed that gene expression and serum profile of antioxidant markers could discriminate peri-parturient period. The overall correctly classified percent was 62.0% and 48.1% for results of gene expression and serum parameters respectively. Profound alteration in antioxidant parameters could be a biomarker to that helps follow-up health during the peri-parturient period in order to minimize the incidence and severity of diseases and, consequently, to build up a good management protocol.

Introduction. The fundamental mechanisms of the body's pathological reaction to coal and dust exposure are hypoxia, excessive activation of free radical processes, structural and metabolic disorders in various organs. Organ-specific molecular defense mechanisms begin to function in the form of changes in the level of proteins with antihypoxic (HIF-3a), chaperone (HSP72), and antioxidant functions (HOx-1 — heme-oxygenase, Prx-1 — peroxiredoxin) under damaging effects. Its high level contributes to the restoration of cells' functional state or indicates significant damage in tissues. Hypoxia and free radical processes are known to lead to severe brain damage and behavioral disorders. To date, little is known about the expression of protective proteins and morphological changes in the brain under prolonged exposure to coal-rock dust on the body. The study aimed to learn the level of intracellular protective proteins HIF-3a, HSP72, HOx-1, Prx-1, and morphological changes in the brain in the dynamics of long-term dust exposure. Materials and methods. Sixty white male Wistar rats weighing 200-250 g of the same age took part in the experiment. Dust exposure was modeled by way of dynamic inhalation priming of rats with coal-rock dust (coal of a gas-fat brand) in an intermittent mode for 12 weeks. We perform morphological studies of the brain after 1, 3, 6, 9, and 12 weeks of dust exposure. The cytosolic fraction of brain tissue researchers determined the expression level of HIF-3a, HSP72, HOx-1, and Prx-1 by Western blot analysis. We selected the activity of free radical processes in the brain tissue. Results. Long-term exposure to coal-rock dust on the body at the morphological level in the brain revealed changes that indicate the development of hypoxia and activation of free radical processes: microvascular disorders, pericellular edema, severe dystrophic damage to neurons, focal loss of neurons, activation of glial cells. Activation of the protective proteins HIF-3a, HSP72, HOx-1, and Prx-1 in the early stages (1–3 weeks) of coal-dust exposure provided compensation for free radical processes in brain neurons. An increase in the duration of dust exposure of more than six weeks influences a low level of HSP72, but high HIF-3a and Prx-1, indicating an increase in hypoxic and free radical damage brain. Conclusions. The results obtained to expand the understanding of the morphological and molecular mechanisms that occur in the brain tissue during prolonged dust exposure to the body are essential for developing methods for organ-specific pharmacological correction. Ethics. We keep, fed and remove the animals from the experiment by the requirements of the guidelines of the Ministry of Health and Social Development of the Russian Federation "On Approval of the Rules of Laboratory Practice" (No. 199n of 01.04.2016), as well as the Guide for the Care and Use of Laboratory Animals (Guide for the Care and Use of Laboratory Animals, 1996). The study was approved by the Bioethical Committee of the Research Institute of Complex Problems of Hygiene and Occupational Diseases (Protocol No. 2 of October 25, 2018).

Melatonin (MT) has been reported to regulate certain plant physiological processes and promote tolerance to different environmental stresses such as salinity. Green bean (Phaseolus vulgaris L. cv. Royal Nel) seedlings were exposed to 200 mM NaCl with or without pre-treatment with 150 μM MT. Salt stress led to a lower chlorophyll content, a reduced photosynthetic activity, increased reactive oxygen species (ROS) contents, and decreased photosystem II (PSII) activity. The application of exogenous MT to green bean seedlings under salt stress improved photosynthetic activity and alleviated the oxidative damages by enhancing the activity of antioxidant enzymes. The expression of catalase (CAT1), glutathione reductase (GR), superoxide dismutase (CuZnSOD1), ascorbate peroxidase (APX), Peroxiredoxin Q (PrxQ), and 2-cysteine peroxiredoxin (2-Cys-Prx) encoding genes was significantly increased under salt stress in green bean seedling compared with the untreated control. However, plants treated with exogenous MT and NaCl had 28.8, 21.1, 26.1, 20, 26.2, and 22.4% higher CuZnSOD, CAT1, APX, GR, PrxQ, and 2-Cys-Prx transcript levels, respectively, compared to NaCl stress alone. Our study revealed the protective mechanisms mediated by exogenous MT application in NaCl stress alleviation and our findings could be used in the management of green bean cultivation in salinity-prone soils.

Responding appropriately to exercise is essential to maintenance of skeletal muscle mass and function at all ages and particularly during aging. Here, a hypothesis is presented that a key component of the inability of skeletal muscle to respond effectively to exercise in aging is a denervation-induced failure of muscle redox signalling. This novel hypothesis proposes that an initial increase in oxidation in muscle mitochondria leads to a paradoxical increase in the reductive state of specific cysteines of signalling proteins in the muscle cytosol that suppresses their ability to respond to normal oxidising redox signals during exercise. The following are presented for consideration:Transient loss of integrity of peripheral motor neurons occurs repeatedly throughout life and is normally rapidly repaired by reinnervation, but this repair process becomes less efficient with aging. Each transient loss of neuromuscular integrity leads to a rapid, large increase in mitochondrial peroxide production in the denervated muscle fibers and in neighbouring muscle fibers. This peroxide may initially act to stimulate axonal sprouting and regeneration, but also stimulates retrograde mitonuclear communication to increase expression of a range of cytoprotective proteins in an attempt to protect the fiber and neighbouring tissues against oxidative damage. The increased peroxide within mitochondria does not lead to an increased cytosolic peroxide, but the increases in adaptive cytoprotective proteins include some located to the muscle cytosol which modify the local cytosol redox environment to induce a more reductive state in key cysteines of specific signalling proteins. Key adaptations of skeletal muscle to exercise involve transient peroxiredoxin oxidation as effectors of redox signalling in the cytosol. This requires sensitive oxidation of key cysteine residues. In aging, the chronic change to a more reductive cytosolic environment prevents the transient oxidation of peroxiredoxin 2 and hence prevents essential adaptations to exercise, thus contributing to loss of muscle mass and function. Experimental approaches suitable for testing the hypothesis are also outlined., Graphical abstract Image 1, Highlights • It is hypothesised that denervation leads to failed redox signalling and attenuated muscle exercise responses in aging. • Loss of peripheral motor neurons leads to increased mitochondrial peroxide in denervated and neighbouring muscle fibers. • This peroxide stimulates increased expression of cytoprotective proteins to protect the fiber against oxidative damage. • Increased mitochondrial peroxide does not increase cytosolic peroxide, but adaptations reduce the cytosol redox state. • Key adaptations of skeletal muscle to exercise involve transient peroxiredoxin oxidation in the cytosol. • Peroxiredoxin oxidation is suppressed during aging by a chronic change to a more reductive local cytosolic environment.

Environmental oxidative stress threatens cellular integrity and should therefore be avoided by living organisms. Yet, relatively little is known about environmental oxidative stress perception. Here, using microfluidics, we showed that like I2 pharyngeal neurons, the tail phasmid PHA neurons function as oxidative stress sensing neurons in C. elegans, but display different responses to H2O2 and light. We uncovered that different but related receptors, GUR-3 and LITE-1, mediate H2O2 signaling in I2 and PHA neurons. Still, the peroxiredoxin PRDX-2 is essential for both, and might promote H2O2-mediated receptor activation. Our work demonstrates that C. elegans can sense a broad range of oxidative stressors using partially distinct H2O2 signaling pathways in head and tail sensillae, and paves the way for further understanding of how the integration of these inputs translates into the appropriate behavior.Graphical abstract

Skeletal muscle generates superoxide during contractions which is rapidly converted to H2O2. This molecule has been proposed to activate signalling pathways and transcription factors that regulate key adaptive responses to exercise but the concentration of H2O2 required to oxidise and activate key signalling proteins in vitro is much higher than the intracellular concentration in muscle fibers following exercise. We hypothesised that Peroxiredoxins (Prx), which reacts with H2O2 at the low intracellular concentrations found in muscle, would be rapidly oxidised in contracting muscle and hence potentially transmit oxidising equivalents to downstream signalling proteins as a method for their oxidation and activation. The aim of this study was to characterise the effects of muscle contractile activity on the oxidation of Prx1, 2 and 3 and determine if these were affected by aging. Prx1, 2 and 3 were all rapidly and reversibly oxidised following treatment with low micromolar concentrations of H2O2 in C2C12 myotubes and also in isolated mature flexor digitalis brevis fibers from adult mice following a protocol of repeated isometric contractions. Significant oxidation of Prx2 was seen within 1 min (i.e. after 12 contractions), whereas significant oxidation was seen after 2 min for Prx1 and 3. In muscle fibers from old mice, Prx2 oxidation was significantly attenuated following contractile activity. Thus we show for the first time that Prx are rapidly and reversibly oxidised in response to contractile activity in skeletal muscle and hypothesise that these proteins act as effectors of muscle redox signalling pathways which are key to adaptations to exercise that are attenuated during aging., Graphical abstract Image 1, Highlights • Hydrogen peroxide is generated by skeletal muscle during contractions. • Peroxiredoxins (Prx) react with H2O2 at the physiological levels generated during contractions. • Prx 1–3 are all oxidised by H2O2 and contractile activity in muscle fibers. • Prx2 oxidation during contractions is attenuated in muscle fibers from old mice. • Prx may act as effectors in activation of redox-regulated adaptations to contractile activity in muscle.

Neoporphyra haitanensis is an economically important red seaweed that inhabits upper intertidal zones. The thallus tolerates extreme fluctuating environmental stresses (e.g., surviving more than 80% water loss during low tides). To elucidate the global molecular responses relevant to this outstanding desiccation tolerance, a quantitative proteomics analysis of N. haitanensis under different desiccation treatments as well as rehydration was performed. According to the clustering of expression patterns and the functional interpretation of the 483 significantly differentially expressed proteins, a three-stage cellular response to desiccation stress and subsequent rehydration was proposed. Stage I: at the beginning of water loss, multiple signal transduction pathways were triggered including lipid signaling, protein phosphorylation cascades, and histone acetylation controlling acetate biosynthesis to further modulate downstream hormone signaling. Protein protection by peptidyl-prolyl isomerase and ROS scavenging systems were also immediately switched on. Stage II: with the aggravation of stress, increases in antioxidant systems, the accumulation of LEA proteins, and the temporary biosynthesis of branched starch were observed. Multiple enzymes involved in redox homeostasis, including peroxiredoxin, thioredoxin, ascorbate peroxidase, superoxide dismutase, glutathione peroxidase, and glutathione reductase, were hypothesized to function in specific cellular compartments. Stage III: when the desiccated thalli had rehydrated for 30 mins, photosynthesis and carbon fixation were recovered, and antioxidant activities and protein structure protection were maintained at a high level. This work increases the understanding of the molecular responses to environmental stresses via a proteomic approach in red seaweeds and paves the way for further functional studies and genetic engineering.

Background Endometriosis (EMT) is a common occurrence in women of reproductive age. Since oxidative stress has been associated with the development and/or progression of the disease, the present study was conducted to detect the expression of peroxiredoxin (PRX) isoforms, including PRX1, PRX2, and PRX3. Methods Fifty-two patients with ovarian endometriosis cysts and 47 controls were included in the study. Serum levels of PRXs were detected by enzyme-linked immunosorbent assay, and the expression of PRX in the endometrium was examined by immunohistochemistry. Results Serum PRX1, PRX2, and PRX3 were significantly lower in EMT patients than in controls. The expression of the three isoforms was significantly decreased in ectopic endometrium compared to that in eutopic or control endometrium. There was no difference in PRX expression between eutopic endometrium of EMT patients and control endometrium, and no association was found between serum PRX levels and immunostaining scores. Conclusion Our results are the first report that PRXs are downregulated in EMT patients, which suggests that PRXs are involved in the oxidative state of the disease.

AhpC is a bacterial representative of 2-Cys peroxiredoxins (Prxs) with broad substrate specificity and functional plasticity. However, details underpinning these two important attributes of AhpC remain unclear. Here, we studied the functions and mechanisms of regulation of AhpC in the facultative Gram-negative anaerobic bacterium Shewanella oneidensis, in which AhpC's physiological roles can be conveniently assessed through its suppression of a plating defect due to the genetic loss of a major catalase. We show that successful suppression can be achieved only when AhpC is produced in a dose- and time-dependent manner through a complex mechanism involving activation of the transcriptional regulator OxyR, transcription attenuation, and translation reduction. By analyzing AhpC truncation variants, we demonstrate that reactivity with organic peroxides (OPs) rather than H2O2 is resilient to mutagenesis, implying that OP reduction is the core catalytic function of AhpC. Intact AhpC could be recycled only by its cognate reductase AhpF, and AhpC variants lacking the Prx domain or the extreme C-terminal five residues became promiscuous electron acceptors from the thioredoxin reductase TrxR and the GSH reductase Gor in addition to AhpF, implicating an additional dimension to functional plasticity of AhpC. Finally, we show that the activity of S. oneidensis AhpC is less affected by mutations than that of its Escherichia coli counterpart. These findings suggest that the physiological roles of bacterial AhpCs are adapted to different oxidative challenges, depending on the organism, and that its functional plasticity is even more extensive than previously reported.

Ebselen is an organoselenium compound exhibiting hydroperoxide- and peroxynitrite-reducing activity, acting as a glutathione peroxidase and peroxiredoxin enzyme mimetic. Ebselen reacts with a multitude of protein thiols, forming a selenosulfide bond, which results in pleiotropic effects of antiviral, antibacterial and anti-inflammatory nature. The main protease (Mpro) of the corona virus SARS-CoV-2 is a potential drug target, and a screen with over 10,000 compounds identified ebselen as a particularly promising inhibitor of Mpro (Jin, Z. et al. (2020) Nature 582, 289–293). We discuss here the reaction of ebselen with cysteine proteases, the role of ebselen in infections with viruses and with other microorganisms. We also discuss effects of ebselen in lung inflammation. In further research on the inhibition of Mpro in SARS-CoV-2, ebselen can serve as a promising lead compound, if the inhibitory effect is confirmed in intact cells in vivo. Independently of this action, potential beneficial effects of ebselen in COVID-19 are ascribed to a number of targets critical to pathogenesis, such as attenuation of inflammatory oxidants and cytokines., Graphical abstract Image 1, Highlights • Ebselen, an organoselenium compound, exhibits anti-inflammatory and antiviral activity. • Ebselen is a glutathione peroxidase and peroxiredoxin mimetic. • Ebselen reacts with a multitude of protein thiols, resulting in pleiotropic effects. • Ebselen is an effective inhibitor of Mpro, the main protease of SARS-CoV-2. • Ebselen may serve as lead compound for drugs targeting COVID-19.

Peroxiredoxin (Prx) refers to a family of thiol-dependent peroxidases that decompose hydrogen peroxide, lipid hydroperoxides, as well as peroxynitrite, and protect against oxidative and inflammatory stress. There are six mammalian Prx isozymes (Prx1-6), classified as typical 2-Cys, atypical 2-Cys, or 1-Cys Prxs based on the mechanism and the number of cysteine residues involved during catalysis. In addition to their well-established peroxide-scavenging activity, some Prxs also participate in the regulation of various cell signaling pathways. Extensive animal studies employing primarily gene knockout models provide substantial evidence supporting a critical protective role of Prxs in various disease processes involving oxidative and inflammatory stress. This review surveys recent research findings, published primarily in influential journals, on the involvement of various Prx isozymes in protecting against cardiovascular injury and related disorders, including diabetes, metabolic syndromes, and sepsis, whose pathophysiology all intimately involves oxidative stress and inflammation.

Peroxiredoxin 6 (Prdx6) is an antioxidant enzyme in the human body that performs a number of important functions in the cell. Prdx6 restores a wide range of peroxide substrates, thus playing a leading role in maintaining redox homeostasis in mammalian cells. In addition to peroxidase activity, Prdx6 has an activity of phospholipase A2, thus taking part in membrane phospholipid metabolism. Due to its peroxidase and phospholipase activity, Prdx6 participates in intracellular and intercellular signal transmission, thereby facilitating the initiation of regenerative processes in the cell, suppression of apoptosis and activation of cell proliferation. Given the functions performed, Prdx6 can effectively deal with oxidative stress caused by various factors, including ischemia-reperfusion injury. On an animal model of rat heterotopic heart transplantation, we showed the cardioprotective potential of exogenous recombinant Prdx6, introduced before transplantation and subsequent reperfusion injury of the heart. It has been demonstrated that exogenous Prdx6 effectively alleviates the severity of ischemia-reperfusion injury of the heart by 2–3 times, providing normalization of its structural and functional state during heterotopic transplantation. The use of recombinant Prdx6 can be an effective approach in preventing/alleviating ischemia-reperfusion injury of the heart, as well as in maintaining an isolated heart during transplantation.

Vitex peduncularis, belongs to the Verbenaceae family, locally known as ‘Boruna’, ‘Horina’, ‘Ashmul gaas’, is commonly used for treating various chronic diseases in the folk medicine such as malarial fevers, jaundice, diabetes, chest pain, joint ache, abnormality in eyes & face, and urethritis, etc. In the present study, we investigated the anxiolytic, sedative, and antioxidant activities of ethanol extract of V. peduncularis leaves (EEVP) in both in vivo and in vitro models. Then, a molecular docking analysis was carried out to determine the possible lead compounds of EEVP for the biological properties described above. The anxiolytic and sedative activity of EEVP was determined using hole board and hole cross tests, respectively. Antioxidant activity was measured using DPPH and FRPA assays, whereas docking was done by using the Schrodinger suite (Maestro v10.1). Our result demonstrated that EEVP has significant and dose-dependent anxiolytic and sedative activity at the doses of 200 and 400 mg/kg (b.w.) in both models. This study also exhibited that EEVP has significant antioxidant activity compared to reference standard ascorbic acid. The molecular docking study revealed that 3,4-dihydroxybenzoic acid, 4-hydroxybenzoic acid, and vitexilactone have the best binding affinities against the target receptors (potassium channel receptor, human gamma-aminobutyric acid receptor, and human peroxiredoxin 5) for anxiolytic, sedative, and antioxidant activities. The present study confirmed that EEVP has anxiolytic, sedative, and antioxidant properties, which could be because of the occurrence of various phytochemicals and three bioactive phytocompounds which found potential during molecular docking analysis.

Microorganism’s cycle exposure to reactive oxidants from internal metabolism and abiotic stress conditions, e.g. oxidative stress, salinity, drought, low temperature, high temperature, and high light. Synechocystis PCC6803 genomes typically encode different types of antioxidant scavenging enzymes including Peroxiredoxins (Prxs). There are five genes similar to Prxs were found inthe Synechocystis PCC 6803 genome. Based on sequence homology analysis of Synechocystis PCC 6803sll1621 gene, it is categorized into type II Prx (PrxII). The presumed amino acid sequence of Synechocystis PCC6803 PrxII protein exhibited identity about 44%-99% to other PrxII proteins from human, plants, algae, and other different cyanobacterial cells. In the last decade, the genetically controllable model organism E. coli has been introduced as a viable biotechnological model for genetically modified microorganisms. The Synechocystis PCC6803 sll1621 gene was overexpressed in pTYB21 expression vector and the resulting was named as pTYB21/sll1621. The pTYB21/sll1621 was overexpressed in Escherichia coli BL21 (DE3) host cell. The overexpressed protein of PrxII gave the recombinant E. coli cells the ability to survive under high concentrations of salinity stress, whereas the viability of wild type cells was completely inhibited at the same high concentrations of salinity stress. In conclusion, the present research documented the expressing of the sll1621 gene into E. coli cells. This result approved the absence of species barrier in relations to the function of Synechocystis PCC 6803 PrxII protein in different microorganism.

Both reactive nitrogen and oxygen species (RNS and ROS), such as nitric oxide, peroxynitrite, and hydrogen peroxide, have been implicated as mediators of pancreatic β-cell damage during the pathogenesis of autoimmune diabetes. While β-cells are thought to be vulnerable to oxidative damage due to reportedly low levels of antioxidant enzymes, such as catalase and glutathione peroxidase, we have shown that they use thioredoxin reductase to detoxify hydrogen peroxide. Thioredoxin reductase is an enzyme that participates in the peroxiredoxin antioxidant cycle. Peroxiredoxins are expressed in β-cells and, when overexpressed, protect against oxidative stress, but the endogenous roles of peroxiredoxins in the protection of β-cells from oxidative damage are unclear. Here, using either glucose oxidase or menadione to continuously deliver hydrogen peroxide, or the combination of dipropylenetriamine NONOate and menadione to continuously deliver peroxynitrite, we tested the hypothesis that β-cells use peroxiredoxins to detoxify both of these reactive species. Either pharmacological peroxiredoxin inhibition with conoidin A or specific depletion of cytoplasmic peroxiredoxin 1 ( Prdx1) using siRNAs sensitizes INS 832/13 cells and rat islets to DNA damage and death induced by hydrogen peroxide or peroxynitrite. Interestingly, depletion of peroxiredoxin 2 ( Prdx2) had no effect. Together, these results suggest that β-cells use cytoplasmic Prdx1 as a primary defense mechanism against both ROS and RNS.

Background Radioresistance of some non-small cell lung cancer (NSCLC) types increases the risk of recurrence or metastasis in afflicted patients, following radiotherapy. As such, further improvements to NSCLC radiotherapy are needed. The expression of oncogene TP53-regulated inhibitor of apoptosis 1 (TRIAP1) in NSCLC is increased following irradiation. Furthermore, gene set enrichment analysis (GSEA) has suggested that TRIAP1 might be involved in maintaining redox homeostasis. This in turn might enhance cell radioresistance. Methods In this study we irradiated human NSCLC cell lines (A549 and H460), while knocking down TRIAP1, to determine whether a disrupted redox homeostasis could attenuate radioresistance. Results Irradiation notably increased both mRNA and protein levels of TRIAP1. In addition, TRIAP1 knockdown decreased the expression of several antioxidant proteins, including thioredoxin-related transmembrane protein (TMX) 1, TMX2, thioredoxin (TXN), glutaredoxin (GLRX) 2, GLRX3, peroxiredoxin (PRDX) 3, PRDX4, and PRDX6 in A549 and H460 cells. In addition, silencing TRIAP1 impaired the radiation-induced increase of the aforementioned proteins. Continuing along this line, we observed a radiation-induced reduction of cell viability and invasion, as well as increased apoptosis and intracellular reactive oxygen species following TRIAP1 knockdown. Conclusions In summary, we identified TRIAP1 as a key contributor to the radioresistance of NSCLC by maintaining redox homeostasis.

Peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α is a transcriptional coactivator described as a master regulator of mitochondrial biogenesis and function, including oxidative phosphorylation and reactive oxygen species detoxification. PGC-1α is highly expressed in tissues with high energy demands, and it is clearly associated with the pathogenesis of metabolic syndrome and its principal complications including obesity, type 2 diabetes mellitus, cardiovascular disease, and hepatic steatosis. We herein review the molecular pathways regulated by PGC-1α, which connect oxidative stress and mitochondrial metabolism with inflammatory response and metabolic syndrome. PGC-1α regulates the expression of mitochondrial antioxidant genes, including manganese superoxide dismutase, catalase, peroxiredoxin 3 and 5, uncoupling protein 2, thioredoxin 2, and thioredoxin reductase and thus prevents oxidative injury and mitochondrial dysfunction. Dysregulation of PGC-1α alters redox homeostasis in cells and exacerbates inflammatory response, which is commonly accompanied by metabolic disturbances. During inflammation, low levels of PGC-1α downregulate mitochondrial antioxidant gene expression, induce oxidative stress, and promote nuclear factor kappa B activation. In metabolic syndrome, which is characterized by a chronic low grade of inflammation, PGC-1α dysregulation modifies the metabolic properties of tissues by altering mitochondrial function and promoting reactive oxygen species accumulation. In conclusion, PGC-1α acts as an essential node connecting metabolic regulation, redox control, and inflammatory pathways, and it is an interesting therapeutic target that may have significant benefits for a number of metabolic diseases.

This study aimed to investigate the involvement of long non-coding RNA (lncRNA) lung adenocarcinoma transcript 1 (LUADT1) LUADT1 in diabetic retinopathy (DR). We found LUADT1 may interact with miR-383 by RNA interaction prediction. QPCR analysis showed that lncRNA LUADT1 was downregulated, and miR-383 was upregulated in DR. However, correlation analysis revealed no significant correlation between them. In retinal pigment epithelial cells (RPEpiC, h1RPE7 from Sigma-Aldrich), overexpression of LUADT1 and miR-383 failed to affect the expression of each other. However, LUADT1 overexpression led to increased and miR-383 overexpression led to decreased expression level of peroxiredoxin 3 (PRX3). Cell apoptosis analysis showed that LUADT1 and PRX3 overexpression resulted in the decreased cell apoptosis. MiR-383 played an opposite role and reduced the effects of LUADT1 and PRX3 overexpression. Therefore, LUADT1 regulates PRX3 by serving as the endogenous sponge of miR-383 in DR to regulate cell apoptosis.

Non-small-cell lung cancer (NSCLC) is one of the most common malignant tumors in the world. Reactive oxidative species (ROS) and nuclear factor-related factor 2 (Nrf2) -antioxidant response element (ARE) signal pathway are known to play important roles in the development of NSCLC. In this study, we identified Peroxiredoxin 5 (PRDX5) as a novel binding partner for Nrf2. PRDX5 was significantly increased in human NSCLC specimens and cell lines. Nrf2 interacted with PRDX5 in H2O2-stimulated NCSLC cells, and the interaction promoted the expression of NAD(P)H: quinone oxidoreductase 1 (NQO1) protein in NSCLC cells. Further, high expression of Nrf2 and PRDX5 were associated with worsened prognosis in patients with NSCLC significantly. Moreover, animal studies showed that the growth of tumors treated with Nrf2 and PRDX5 shRNA was significantly lower than that of the other groups. All these data indicated that overexpressed PRDX5 in NSCLC promoted binding with Nrf2 and enhanced NQO1 expression and NSCLC development. Overall, our studies demonstrated that PRDX5 can be a novel binding partner of Nrf2 in promoting NCSLC development under oxidative stress and provide potential opportunity for improving NSCLC therapy.

The marked heterogeneity of autism spectrum disorders is a challenge for research into biomarkers of these disorders. The present study aimed to assess the association of the thioredoxin (TRX) system and vasopressin with autism in children. Thirty-five autistic children were recruited with thirty-one healthy controls children matched for age and gender. Total antioxidant capacity (TAC), vasopressin, peroxiredoxin (PRDX1, PRDX3), phox domain-containing protein kinase-like protein, and TRX1 levels were measured in plasma and mercury and lead levels were measured in red blood cells. Children with autism had significantly lower levels of PRDX1 and TRX1 and significantly higher levels of lead and mercury compared with controls. Significantly higher levels of vasopressin were also observed in more severe cases of autism. Receiver operating characteristics analysis demonstrated satisfactory specificity and sensitivity of TAC, PRDX1, PRDX3, and TRX1 for the diagnosis of autism. The optimal cut-off value for plasma TRX1 levels, as an indicator of autism, was 10.6 ng/mL. Significant positive correlations existed between TRX system components, lead, and mercury. A negative correlation was found between vasopressin and TRX1, but positive correlations were found between vasopressin and mercury and lead. In conclusion, TAC, PRDX1, PRDX3, and TRX1 may be useful biomarkers for the diagnosis of autism in Saudi populations. Vasopressin-resistance in autistic patients may be due to an increased oxidative burden.

Typical 2-cysteine peroxiredoxins (2-Cys Prxs) are critical peroxidase sensors and could be deactivated by the hyperoxidation under oxidative stress. In plants, 2-Cys Prxs present at a high level in chloroplasts and are repaired by Sulfiredoxin. Whereas many studies have explored the mechanism of Sulfiredoxin from Homo sapiens (HsSrx), the molecular mechanism of Sulfiredoxin in plants with unique photosynthesis remains unclear. Here we report the crystal structure of Sulfiredoxin from Arabidopsis thaliana (AtSrx), which displayed a typical ParB/Srx fold with an ATP bound at a conservative nucleotide binding motif GCHR. Both the ADP binding pocket and the putative AtSrx-AtPrxA interaction surface of AtSrx are more positively charged comparing to HsSrx, suggesting a robust mechanism of AtSrx. These features illustrate the unique mechanisms of AtSrx, which are vital for figure out the strategies of plants to cope with oxidation stress.

Nitroreductases (NTRs) catalyze the reduction of a wide range of nitro-compounds and quinones using NAD(P)H. Although the physiological functions of these enzymes remain obscure, a tentative function of resistance to reactive oxygen species (ROS) via the detoxification of menadione has been proposed. This suggestion is based primarily on the transcriptional or translational induction of an NTR response to menadione rather than on convincing experimental evidence. We investigated the performance of a fungal NTR from Aspergillus nidulans (AnNTR) exposed to menadione to address the question of whether NTR is really an ROS defense enzyme. We confirmed that AnNTR was transcriptionally induced by external menadione. We observed that menadione treatment generated cytotoxic levels of O(2)(•−), which requires well-known antioxidant enzymes such as superoxide dismutase, catalase, and peroxiredoxin to protect A. nidulans against menadione-derived ROS stress. However, AnNTR was counterproductive for ROS defense, since knocking out AnNTR decreased the intracellular O(2)(•−) levels, resulting in fungal viability higher than that of the wild type. This observation implies that AnNTR may accelerate the generation of O(2)(•−) from menadione. Our in vitro experiments indicated that AnNTR uses NADPH to reduce menadione in a single-electron reaction, and the subsequent semiquinone-quinone redox cycling resulted in O(2)(•−) generation. We demonstrated that A. nidulans nitroreductase should be an ROS generator, but not an ROS scavenger, in the presence of menadione. Our results clarified the relationship between nitroreductase and menadione-derived ROS stress, which has long been ambiguous. IMPORTANCE Menadione is commonly used as an O(2)(•−) generator in studies of oxidative stress responses. However, the precise mechanism through which menadione mediates cellular O(2)(•−) generation, as well as the way in which cells respond, remains unclear. Elucidating these events will have important implications for the use of menadione in biological and medical studies. Our results show that the production of Aspergillus nidulans nitroreductase (AnNTR) was induced by menadione. However, the accumulated AnNTR did not protect cells but instead increased the cytotoxic effect of menadione through a single-electron reduction reaction. Our finding that nitroreductase is involved in the menadione-mediated O(2)(•−) generation pathway has clarified the relationship between nitroreductase and menadione-derived ROS stress, which has long been ambiguous.

Macrophages promote early host responses to infection by releasing pro-inflammatory cytokines, and they are crucial to combat amoebiasis, a disease affecting millions of people worldwide. Macrophages elicit pro-inflammatory responses following direct cell/cell interaction of Entamoeba histolytica, inducing NLRP3 inflammasome activation with high-output IL-1β/IL-18 secretion. Here, we found that trophozoites could upregulate peroxiredoxins (Prx) expression and abundantly secrete Prxs when encountering host cells. The C-terminal of Prx was identified as the key functional domain in promoting NLRP3 inflammasome activation, and a recombinant C-terminal domain could act directly on macrophage. The Prxs derived from E. histolytica triggered toll-like receptor 4-dependent activation of NLRP3 inflammasome in a cell/cell contact-independent manner. Through genetic, immunoblotting or pharmacological inhibition methods, NLRP3 inflammasome activation was induced through caspase-1-dependent canonical pathway. Our data suggest that E. histolytica Prxs had stable and durable cell/cell contact-independent effects on macrophages following abundantly secretion during invasion, and the C-terminal of Prx was responsible for activating NLRP3 inflammasome in macrophages. This new alternative pathway may represent a potential novel therapeutic approach for amoebiasis, a global threat to millions.

Peroxiredoxin-4 (PRDX4), an endoplasmic reticulum peroxiredoxin protein, plays a protective role against oxidative stress and inflammation by reducing hydrogen peroxide to water. The dopamine D5 receptor (D 5 R) is also important in protecting against oxidative stress, but the interaction between PRDX4 and D 5 R in regulating oxidative stress in the kidney is not known. In D 5 R-HEK 293 cells, fenoldopam (FEN, 25 nM/12 hr, n=4), a D1-likereceptor agonist, increased PRDX4 protein expression (1.92±0.12-fold over basal level, n=4), mainly in non-lipid rafts (LRs: 24.9±11.4%, non-LRs: 75.1±11.4%, baseline; LRs: 30.9±13.9%, non-LRs: 174.1±16.7%, FEN). FEN also increased the co-immunoprecipitation of D 5 R and PRDX4 and their colocalization, particularly in the endoplasmic reticulum. In human renal proximal tubule cells (hRPTCs), FEN (25 nM/12 hr, n=3) increased PRDX4 and D 5 R interaction in non-LRs, also. Si-RNA silencing of PRDX4 increased reactive oxygen species (ROS) production and impaired the inhibitory effect of FEN on ROS production (scrambled siRNA: 100.0±11.6% and 65.4±5.6% for Vehicle (Veh) and FEN, respectively; PRDX4 siRNA: 147.7±11.8% and 134.8±11.2% for Veh and FEN, respectively, n=4/group) detected by Amplex Red. In addition in both D 5 R-HEK 293 and hRPTCs, siRNA silencing of PRDX4 increased the production of interleukin-1β (26.88±3.8 and 46.40±4.2 pg/mL [n=3, D 5 R-HEK 293]; 15.87±1.2 and 37.9±1.4 pg/mL [n=3 in hRPTCs]), tumor necrosis factor (131.7±6.5 and 271.2±18.1 pg/mL [n=4, D 5 R-HEK 293]; 108.8±11.8 and 240.1±13.7 pg/mL [n=4 in hRPTCs]), and caspase-12 (15.21±3.8 and 40.78±4.3 ng/mL [n=4,n D 5 R-HEK 293]; 8.8±1.1 and 27.9±2.0 ng/mL [n=4, hRPTCs]). Furthermore, the protein expression of D 5 R was decreased in PRDX4 siRNA-treated D 5 R-HEK293 (~41.2%, n=3) and hRPTCs (~39.6%, n=3). PRDX4 protein was also reduced in the kidney homogenates from D 5 R -/- mice (WT: 1.00±0.18, n=5; D 5 R -/- : 0.686±0.14, n=4; P5 R to decrease oxidative stress and inflammation in the kidney.

Oxidative stress is hypothesized to play a role in pancreatic β-cell damage, potentially contributing to β-cell dysfunction and death in both type 1 and type 2 diabetes. Oxidative stress arises when naturally occurring reactive oxygen species (ROS) are produced at levels that overwhelm the antioxidant capacity of the cell. ROS, including superoxide and hydrogen peroxide, are primarily produced by electron leak during mitochondrial oxidative metabolism. Additionally, peroxynitrite, an oxidant generated by the reaction of superoxide and nitric oxide, may also cause β-cell damage during autoimmune destruction of these cells. β-cells are thought to be susceptible to oxidative damage based on reports that they express low levels of antioxidant enzymes compared to other tissues. Furthermore, markers of oxidative damage are observed in islets from diabetic rodent models and human patients. However, recent studies have demonstrated high expression of various isoforms of peroxiredoxins, thioredoxin, and thioredoxin reductase in β-cells and have provided experimental evidence supporting a role for these enzymes in promoting β-cell function and survival in response to a variety of oxidative stressors. This mini-review will focus on the mechanism by which thioredoxins and peroxiredoxins detoxify ROS and on the protective roles of these enzymes in β-cells. Additionally, we speculate about the role of this antioxidant system in promoting insulin secretion.

Smoke exposure is a risk factor for community acquired pneumonia, which is typically caused by host adapted opportunists like nontypeable Haemophilus influenzae (NTHi). Genomic analyses of NTHi revealed homologs of enzymes involved in thiol metabolism, which can have key roles in oxidant resistance. Using a clinical NTHi isolate (NTHi 7P49H1), we generated isogenic mutant bacterial strains in which homologs of glutathione reductase (NTHI 0251), thiol peroxidase (NTHI 0361), thiol peroxidase (NTHI 0907), thioredoxin reductase (NTHI 1327) and glutaredoxin/peroxiredoxin (NTHI 0705) were inactivated. Bacterial protein analyses revealed significant increases in protein oxidation after oxidative stress for all the mutant strains. Similarly, each of these mutants were less resistant to oxidative killing compared with the parental strain; these phenotypes were reversed by genetic complementation. Quantitative confocal analysis of biofilms showed reducted biofilm thickness and density, and significant sensitization of bacteria within the biofilm structure to oxidative killing for thiol mutant strains. Smoke-exposed mice infected with NTHi 7P49H1 showed significantly increased lung bacterial load, as compared to control mice. Immunofluorescent staining of lung tissues showed NTHi communities on the lung mucosa, interspersed with host neutrophil extracellular traps; these bacteria had surface moieties associated with the Hi biofilm matrix, and transcript profiles consistent with NTHi biofilms. In contrast, infection with the panel of NTHi mutants showed significant decrease in lung bacterial load. Comparable results were observed in bactericidal assays with neutrophil extracellular traps in vitro. Thus, we conclude that thiol mediated redox homeostasis promotes persistence of NTHi within biofilm communities.ImportanceChronic bacterial respiratory infections are a significant problem for smoke exposed individuals, especially those with chronic obstructive pulmonary disease (COPD). These infections often persist despite antibiotic use. Thus, the bacteria remain and contribute to the development of inflammation and other respiratory problems. Respiratory bacteria often form biofilms within the lungs, while growing in a biofilm their antibiotic and oxidative stress resistance is incredibly heightened. It is well documented that redox homeostasis genes are upregulated during this phase of growth. Many common respiratory pathogens such as NTHi and Streptococcus pneumoniae are reliant on scavenging from the host the necessary components they need to maintain these redox systems. This work here begins to lay down the foundation for exploiting this requirement and thiol redox homeostasis pathways of these bacteria as a therapeutic target for managing chronic respiratory bacterial infections, which are resistant to traditional antibiotic treatments alone.

Entamoeba histolytica is the conductive agent of amoebiasis. Upon the parasite's infection, macrophages and neutrophils are activated by Interferon γ (IFN-γ), IL-13, and Tumour Necrosis Factor (TNF-α). These immune cells then carry out the amoebicidal activity by releasing Nitric Oxide Synthase (NOS) and Reactive Oxygen Species (ROS). This review talks about the protective and destructive role of ROS in Eh. E. histolytica has defense strategies against oxidative stress which is a result of excess ROS production. They possess antioxidants for their defense such as L-Cysteine, Flavodiiron proteins (FDPs), Peroxiredoxin, and Trichostatin A, which contribute to the parasite's virulence. The reactive oxygen species are harmful to the host cells as excess ROS production stimulates cell death by mechanisms like apoptosis and necroptosis. NADPH oxidase (NOX) is a key source of ROS in mammalian cells and causes apoptosis of host cells via the protein kinase transduction pathway. This review provides insights into why NOX inhibitors that could be a potent antiparasitic drug, is not effective for in vivo purposes. This paper also gives an insight into a solution that could be a potent source in generating new treatment and vaccines for amoebiasis by targeting parasite development.

Reactive oxygen species (ROS) are recognized as important signaling molecules in healthy skeletal muscle. Redox sensitive proteins can respond to intracellular changes in ROS by oxidation of reactive thiol groups on cysteine (Cys) residues. Exercise is known to induce the generation of superoxide and nitric oxide, resulting in the activation of several adaptive signaling pathways; however, it has been suggested that aging attenuates these redox-regulated adaptations to acute exercise. In the present study, we used redox proteomics to study the vastus lateralis muscles of Adult (n = 6 male, 6 female; 18–30 yrs) and Old (n = 6 male, 6 female; 64–79 yrs) adults. Participants completed a bout of high intensity cycling exercise consisting of five sets of 2-min intervals performed at 80% maximal aerobic power output (PPO), with 2 min recovery cycling at 40% PPO between sets. Muscle biopsies were collected prior to exercise, and immediately following the first, second, and fifth high intensity interval. Global proteomic analysis indicated differences in abundance of a number of individual proteins between skeletal muscles of Adult and Old subjects at rest with a significant exacerbation of these differences induced by the acute exercise. In particular, we observed an exercise-induced decrease in abundance of mitochondrial proteins in muscles from older subjects only. Redox proteome analysis revealed cysteines from five cytosolic proteins in older subjects with lower oxidation (i.e. greater reduction) than was seen in muscle from the young adults at rest. Redox homeostasis was well maintained in Adult subjects following exercise, but there was significant increase in oxidation of multiple mitochondrial and cytosolic protein cysteines in Old subjects. We also observed that oxidation of peroxiredoxin 3 occurred following exercise in both Adult and Old groups, supporting the possibility that this is a key effector protein for mitochondrial redox signaling. Thus, we show, for the first time that exercise reveals a lack of resilience in muscle of older human participants, that is apparent as a loss of mitochondrial proteins and oxidation of multiple protein cysteines that are not seen in younger subjects. The precise consequences of this redox disruption are unclear, but this likely play a role in the attenuation of multiple adaptations to exercise that are classically seen with aging. Such changes were only seen following the acute stress of exercise., highlighting the need to consider not only basal differences seen during aging but also the difference following physiological challenge.

Sarcopenia, the age-related decline in muscle mass and function, derives from multiple etiological mechanisms. Accumulative research suggests that reactive oxygen species (ROS) generation plays a critical role in the development of this pathophysiological disorder. In this communication, we review the various signaling pathways that control muscle metabolic and functional integrity such as protein turnover, cell death and regeneration, inflammation, organismic damage, and metabolic functions. Although no single pathway can be identified as the most crucial factor that causes sarcopenia, age-associated dysregulation of redox signaling appears to underlie many deteriorations at physiological, subcellular, and molecular levels. Furthermore, discord of mitochondrial homeostasis with aging affects most observed problems and requires our attention. The search for the primary suspect of the fundamental mechanism for sarcopenia will likely take more intense research for the secret of this health hazard to the elderly to be unlocked.

The peroxiredoxin 5 (PRDX5) is a member of peroxiredoxins with antitumor activity. However, as a recombinant protein, PRDX5 is restricted in clinic due to high cost and keeping high dose in medication. The alternative way is to explore the antitumor active fragments of PRDX5 for potential of peptide drugs. According to the sequence, crystal structure and enzyme function of PRDX5, seven peptides were designed and named as IMB-P1∼7. The peptide IMB-P1 (AFTPGCSKTHLPGFVEQAEAL) containing critical residue C47 exhibited antitumor activity similar to PRDX5 in vivo. Transcriptome analysis showed peptide IMB-P1 could make influence on expression of multiple genes involved in tumorigenesis and deterioration. Besides, an important discovery is the down-regulation of oxidation-related genes. In CT26 cells, IMB-P1 carried similar antitumor activity with increasing ROS level to intact PRDX5. The results demonstrated that peptide IMB-P1 with easier synthesis from PRDX5 may serve as a promising antitumor candidate.

Rhynchosia ferruginea (Udusalim, Afan Oromo) is a medicinal plant traditionally used to treat skin infection, intestinal problems and amoebiasis. Silica gel chromatographic separation of dichloromethane/methanol (1:1) roots extract yielded isoflavan (1), isoflavene (2) and 1, 3-dilinoleoyl-2-stearoylglycerol (3), reported herein for the first time from the genus. Antibacterial activity was examined using disc diffusion method against E. coli, S. aureus, P. aeruginosa and S. pyogenes. AutoDoc vina 4.2 soft ware was used for molecular docking analysis of compounds against human peroxidoxin 5 and DNA gyrase B enzymes. Isoflavan (1) displayed zone of inhibition of 9.67 ± 0.58 mm and 10.67 ± 0.58 mm whereas isoflavene (2) showed 10.33 ± 1.15 mm and 10 ± 1.00 mm against E. coli and S. aureus, respectively, compared to ciprofloxacin (15.67±0.58 mm for both strains). DPPH radical scavenging assay of the dichloromethane/methanol (1:1) roots extract and isoflavan (1) exhibited better radical scavenging activity with IC50 value of 17.7 and 32, respectively. Molecular docking analysis revealed that 1 and 2 exhibited similar binding affinity of -7.4 kcal/mol compared to ciprofloxacin (-7.3 kcal/mol). In silico analysis against human peroxidoxin 5 (PDB ID: 1HD2) revealed minimum binding affinity of - 3.7 and - 2.0 kcal/mol for compounds 1 and 2, respectively, compared to ascorbic acid (-4.9 kcal/mol). The in vitro antibacterial and antioxidant activity of compounds 1 and 2 suggest the potential use of these compounds as drug lead candidates which corroborate with the traditional uses of the roots of R. ferruginea.

Background Alcoholic liver disease (ALD) is the most common liver disease worldwide and its underlying molecular mechanisms are still poorly understood. Moreover, conflicting data have been reported on potentially protective autophagy, the exact role of ethanol-metabolizing enzymes and ROS. Methods Expression of LC3B, CYP2E1, and NOX4 was studied in a mouse model of acute ethanol exposure by immunoblotting and immunohistochemistry. Autophagy was further studied in primary mouse hepatocytes and huh7 cells in response to ethanol and its major intermediator acetaldehyde. Experiments were carried out in cells overexpressing CYP2E1 and knock down of NOX4 using siRNA. The response to external H2O2 was studied by using the GOX/CAT system. Autophagic flux was monitored using the mRFP-GFP-LC3 plasmid, while rapamycin and chloroquine served as positive and negative controls. Results Acute ethanol exposure of mice over 24 h significantly induced autophagy as measured by LC3B expression but also induced the ROS-generating CYP2E1 and NOX4 enzymes. Notably, ethanol but not its downstream metabolite acetaldehyde induced autophagy in primary mouse hepatocytes. In contrast, autophagy could only be induced in huh7 cells in the presence of overexpressed CYP2E1. In addition, overexpression of NOX4 also significantly increased autophagy, which could be blocked by siRNA mediated knock down. The antioxidant N-acetylcysteine (NAC) also efficiently blocked CYP2E1-and NOX4-mediated induction of autophagy. Finally, specific and non-toxic production of H2O2 by the GOX/CAT system as evidenced by elevated peroxiredoxin (Prx-2) also induced LC3B which was efficiently blocked by NAC. H2O2 strongly increased the autophagic flux as measured by mRFP-GFP-LC3 plasmid. Conclusion We here provide evidence that short-term ethanol exposure induces autophagy in hepatocytes both in vivo and in vitro through the generation of ROS. These data suggest that suppression of autophagy by ethanol is most likely due to longer alcohol exposure during chronic alcohol consumption with the accumulation of e.g. misfolded proteins., Graphical abstract Image 1, Highlights • Generation of ROS is the major mechanism of autophagy activation during ethanol exposure in acute alcoholic liver disease (ALD). • Non-toxic H2O2 significantly induces autophagy without the engagement of mTOR suppression. • Important ROS-generating enzymes CYP2E1 and NOX4 are strongly induced in a mice model of acute alcohol exposure.

Simple Summary Performance traits and mortality are negatively affected by heat stress. The responses of chickens to HS are extremely complex. Understanding of the molecular mechanism of DNA methylation and the TXN system under HS may provide a new strategy to mitigate the effect of HS. Based on our results, the thioredoxin pathway system under HS may provide clues to nutritional strategies to mitigate the effect of HS in meat-type chicken. Abstract Heat stress (HS) causes molecular dysfunction that adversely affects chicken performance and increases mortality. The responses of chickens to HS are extremely complex. Thus, the aim of this study was to evaluate the influence of acute and chronic exposure to HS on the expression of thioredoxin–peroxiredoxin system genes and DNA methylation in chickens. Chickens at 14 d of age were divided into two groups and reared under either constant normal temperature (25 °C) or high temperature (35 °C) in individual cages for 12 days. Five birds per group at one and 12 days post-HS were euthanized and livers were sampled for gene expression. The liver and Pectoralis major muscle were sampled for cellular analysis. mRNA expression of thioredoxin and peroxiredoxins (Prdx) 1, 3, and 4 in the liver were down-regulated at 12 days post-HS compared to controls. The liver activity of thioredoxin reductase (TXNRD) and levels of peroxiredoxin1 (Prdx1) at 12 days post-HS were significantly decreased. The results reveal that there was a significant decrease in DNA methylation at 12 days post HS in liver tissues. In conclusion, pathway of thioredoxin system under HS may provide clues to nutritional strategies to mitigate the effect of HS in meat-type chicken.

Colorectal cancer is the most common gastrointestinal cancer and causes severe damage to human health. PRDX2 is a member of the peroxiredoxin family reported to have a high level of expression in colorectal cancer. However, the mechanisms by which PRDX2 promotes the proliferation of colorectal cancer are still unclear. Here, the results indicated that PRDX2 expression was upregulated in colorectal cancer and closely correlated with poor prognosis. Functionally, PRDX2 promoted the proliferation of colorectal cancer cells. Mechanistically, PRDX2 could bind RPL4, reducing the interaction between RPL4 and MDM2. These findings demonstrate that the oncogenic property of PRDX2 may be attributed to its regulation of the RPL4-MDM2-p53 pathway, leading to p53 ubiquitinated degradation.

Toxoplasma gondii is one of the most widespread apicomplexans and can cause serious infections in humans and animals. Its antioxidant system plays an important role in defending against oxidant stress imposed by the host. Some genes encoding the antioxidant enzymes of T. gondii have been identified; however, critical genes that function in response to reactive oxygen species (ROS) stress are still poorly understood. Here, we performed genome-wide CRISPR/Cas9 loss-of-function screening in the T. gondii RH strain to identify potential genes contributing to the ROS stress response. Under hydrogen peroxide treatment, 30 single guide RNAs targeting high-confidence genes were identified, including some known important antioxidant genes such as catalase and peroxiredoxin PRX3. In addition, several previously uncharacterized genes were identified, among which five hypothetical protein-coding genes, namely, HP1–HP5, were selected for further functional characterization. Targeted deletion of HP1 in T. gondii RH led to significant sensitivity to H2O2, suggesting that HP1 is critical for oxidative stress management. Furthermore, loss of HP1 led to decreased antioxidant capacity, invasion efficiency, and proliferation in vitro. In vivo results also revealed that the survival time of mice infected with the HP1-KO strain was significantly prolonged relative to that of mice infected with the wild-type strain. Altogether, these findings demonstrate that the CRISPR/Cas9 system can be used to identify potential genes critical for oxidative stress management. Furthermore, HP1 may confer protection against oxidative damage and contributes to T. gondii virulence in mice.

Enhanced production of reactive oxygen species (ROS) triggered by various stimuli, including viral infections, has attributed much attention in the past years. It has been shown that different viruses that cause acute or chronic diseases induce oxidative stress in infected cells and dysregulate antioxidant its antioxidant capacity. However, most studies focused on catalase and superoxide dismutases, whereas a family of peroxiredoxins (Prdx), the most effective peroxide scavengers, were given little or no attention. In the current review, we demonstrate that peroxiredoxins scavenge hydrogen and organic peroxides at their physiological concentrations at various cell compartments, unlike many other antioxidant enzymes, and discuss their recycling. We also provide data on the regulation of their expression by various transcription factors, as they can be compared with the imprint of viruses on transcriptional machinery. Next, we discuss the involvement of peroxiredoxins in transferring signals from ROS on specific proteins by promoting the oxidation of target cysteine groups, as well as briefly demonstrate evidence of nonenzymatic, chaperone, functions of Prdx. Finally, we give an account of the current state of research of peroxiredoxins for various viruses. These data clearly show that Prdx have not been given proper attention despite all the achievements in general redox biology.