Redox regulation of cellular functions

Transmembrane Graphene as an Electron Tunnel to Regulate the Intracellular Redox State

Cellular redox homeostasis is essential for maintaining cellular activities, such as DNA synthesis and gene expression. Inspired by this, new therapeutic interventions have been rapidly developed to modulate the intracellular redox state using artificial transmembrane electron transport. However, current approaches that rely on external electric field polarization can disrupt cellular functions, limiting their in vivo application. Therefore, it is crucial to develop novel electric-field-free modulation methods. In this work, we for the first time found that graphene could spontaneously insert into living cell membranes and serve as an electron tunnel to regulate intracellular reactive oxygen species and NADH based on the spontaneous bipolar electrochemical reaction mechanism. This work provides a wireless and electric-field-free approach to regulating cellular redox states directly and offers possibilities for biological applications such as cell process intervention and treatment for neurodegenerative diseases.

Response mechanism of carbon metabolism of Pinus massoniana to gradient high temperature and drought stress

BACKGROUND

The carbon metabolism pathway is of paramount importance for the growth and development of plants, exerting a pivotal regulatory role in stress responses. The exacerbation of drought impacts on the plant carbon cycle due to global warming necessitates comprehensive investigation into the response mechanisms of Masson Pine (Pinus massoniana Lamb.), an exemplary pioneer drought-tolerant tree, thereby establishing a foundation for predicting future forest ecosystem responses to climate change.

RESULTS

The seedlings of Masson Pine were utilized as experimental materials in this study, and the transcriptome, metabolome, and photosynthesis were assessed under varying temperatures and drought intensities. The findings demonstrated that the impact of high temperature and drought on the photosynthetic rate and transpiration rate of Masson Pine seedlings was more pronounced compared to individual stressors. The analysis of transcriptome data revealed that the carbon metabolic pathways of Masson Pine seedlings were significantly influenced by high temperature and drought co-stress, with a particular impact on genes involved in starch and sucrose metabolism. The metabolome analysis revealed that only trehalose and Galactose 1-phosphate were specifically associated with the starch and sucrose metabolic pathways. Furthermore, the trehalose metabolic heat map was constructed by integrating metabolome and transcriptome data, revealing a significant increase in trehalose levels across all three comparison groups. Additionally, the PmTPS1, PmTPS5, and PmTPPD genes were identified as key regulatory genes governing trehalose accumulation.

CONCLUSIONS

The combined effects of high temperature and drought on photosynthetic rate, transpiration rate, transcriptome, and metabolome were more pronounced than those induced by either high temperature or drought alone. Starch and sucrose metabolism emerged as the pivotal carbon metabolic pathways in response to high temperature and drought stress in Masson pine. Trehalose along with PmTPS1, PmTPS5, and PmTPPD genes played crucial roles as metabolites and key regulators within the starch and sucrose metabolism.

Phytoplankton interspecific interactions modified by symbiotic fungi and bacterial metabolites under environmentally relevant hydrogen peroxide concentrations stress

Hydrogen peroxide (H2O2), which accumulates in water and triggers oxidative stress for aquatic microbes, has been shown to have profound impacts on planktonic microbial community dynamics including cyanobacterial bloom formation. Yet, potential effects of H2O2 on interspecific relationships of phytoplankton-microbe symbiotic interactions remain unclear. Here, we investigated effects of environmentally relevant H2O2 concentrations on interspecific microbial relationships in algae-microbe symbiosis. Microbes play a crucial role in the competition between M. aeruginosa and Chlorella vulgaris at low H2O2 concentrations (∼400 nM), in which fungi and bacteria protect Microcystis aeruginosa from oxidative stress. Moreover, H2O2 stimulated the synthesis and release of extracellular microcystin-LR from Microcystis aeruginosa, while intracellular microcystin-LR concentrations remained at a relatively constant level. In the presence of H2O2, loss of organoheterocyclic compounds, organic acids and ketones contributed to the growth of M. aeruginosa, but the reduction of vitamins inhibited it. Regulation of interspecific relationships by H2O2 is achieved by its action on fungal species and bacterial secretory metabolites. This study explored the response of phytoplankton interspecific relationships in symbiotic phytoplankton-microbe interactions to environmentally relevant H2O2 concentrations stress, providing a theoretical basis for understanding the formation of harmful-algae blooming and impact of photochemical properties of water on aquatic ecological safety and stability.

Commentary: Aldehyde dehydrogenase, redox balance and exercise physiology: What is missing?

Aldehyde dehydrogenase 2 (ALDH2) is a mitochondrial enzyme involved in reactive aldehyde detoxification. Approximately 560 million people (about 8% of the world's population) carry a point mutation in the aldehyde dehydrogenase 2 gene (ALDH2), identified as ALDH2*2, which leads to decreased ALDH2 catalytic activity. ALDH2*2 variant is associated with an accumulation of toxic reactive aldehydes and consequent disruption of cellular metabolism, which contributes to the establishment and progression of several degenerative diseases. Consequences of aldehyde accumulation include impaired mitochondrial functional, hindered anabolic signaling in the skeletal muscle, impaired cardiovascular and pulmonary function, and reduced osteoblastogenesis. Considering that aldehydes are endogenously produced through redox processes, it is expected that conditions that have a high energy demand, such as exercise, might be affected by impaired aldehyde clearance in ALDH2*2 individuals. Despite the large body of evidence supporting the importance of ALDH2 to ethanol metabolism, redox homeostasis and overall health, specific research investigating the impact of ALDH2*2 on phenotypes relevant to exercise performance are notoriously scarce. In this commentary, we highlight the consolidated knowledge on the impact of ALDH2*2 on physiological processes that are relevant to exercise.

Chemical background of silver nanoparticles interfering with mammalian copper metabolism

The rapidly increasing application of silver nanoparticles (AgNPs) boosts their release into the environment, which raises a reasonable alarm for ecologists and health specialists. This is manifested as increased research devoted to the influence of AgNPs on physiological and cellular processes in various model systems, including mammals. The topic of the present paper is the ability of silver to interfere with copper metabolism, the potential health effects of this interference, and the danger of low silver concentrations to humans. The chemical properties of ionic and nanoparticle silver, supporting the possibility of silver release by AgNPs in extracellular and intracellular compartments of mammals, are discussed. The possibility of justified use of silver for the treatment of some severe diseases, including tumors and viral infections, based on the specific molecular mechanisms of the decrease in copper status by silver ions released from AgNPs is also discussed.

Features of oxidative stress in alcoholism

The review considers molecular mechanisms underlying formation and development of oxidative stress (OS) in patients with alcohol dependence. The major attention is paid to the effects of ethanol and its metabolite acetaldehyde associated with additional sources of generation of reactive oxygen species (ROS) in response to exogenous ethanol. The own results of studies of the in vitro effect of ethanol and acetaldehyde on the concentration of peripheral OS markers - products of oxidative modification of proteins (protein carbonyls), lipids (lipid peroxidation products), DNA (8-hydroxy-2-deoxyguanosine, 8-OHdG) in blood plasma are presented. The changes in these parameters and the activity of antioxidant enzymes (SOD, catalase) in patients with alcohol dependence were analyzed. Own and literature data indicate that at a certain stage of the disease OS can play a protective rather than pathogenic role in the body.

Exploring the Role of Lipid-Binding Proteins and Oxidative Stress in Neurodegenerative Disorders: A Focus on the Neuroprotective Effects of Nutraceutical Supplementation and Physical Exercise

The human brain is primarily composed of lipids, and their homeostasis is crucial to carry on normal neuronal functions. In order to provide an adequate amount of lipid transport in and out of the central nervous system, organisms need a set of proteins able to bind them. Therefore, alterations in the structure or function of lipid-binding proteins negatively affect brain homeostasis, as well as increase inflammation and oxidative stress with the consequent risk of neurodegeneration. In this regard, lifestyle changes seem to be protective against neurodegenerative processes. Nutraceutical supplementation with antioxidant molecules has proven to be useful in proving cognitive functions. Additionally, regular physical activity seems to protect neuronal vitality and increases antioxidant defenses. The aim of the present review was to investigate mechanisms that link lipid-binding protein dysfunction and oxidative stress to cognitive decline, also underlining the neuroprotective effects of diet and exercise.

NADPH production in dark stages is critical for cyanobacterial photocurrent generation: a study using mutants deficient in oxidative pentose phosphate pathway

Live cyanobacteria and algae integrated onto an extracellular electrode can generate a light-induced current (i.e., a photocurrent). Although the photocurrent is expected to be correlated with the redox environment of the photosynthetic cells, the relationship between the photocurrent and the cellular redox state is poorly understood. Here, we investigated the effect of the reduced nicotinamide adenine dinucleotide phosphate [NADP(H)] redox level of cyanobacterial cells (before light exposure) on the photocurrent using several mutants (Δzwf, Δgnd, and ΔglgP) deficient in the oxidative pentose phosphate (OPP) pathway, which is the metabolic pathway that produces NADPH in darkness. The NAD(P)H redox level and photocurrent in the cyanobacterium Synechocystis sp. PCC 6803 were measured noninvasively. Dysfunction of the OPP pathway led to oxidation of the photosynthetic NADPH pool in darkness. In addition, photocurrent induction was retarded and the current density was lower in Δzwf, Δgnd, and ΔglgP than in wild-type cells. Exogenously added glucose compensated the phenotype of ΔglgP and drove the OPP pathway in the mutant, resulting in an increase in the photocurrent. The results indicated that NADPH accumulated by the OPP pathway before illumination is a key factor for the generation of a photocurrent. In addition, measuring the photocurrent can be a non-invasive approach to estimate the cellular redox level related to NADP(H) pool in cyanobacteria.

Synechococcus sp. PCC7002 Uses Peroxiredoxin to Cope with Reactive Sulfur Species Stress

Cyanobacteria are a widely distributed group of microorganisms in the ocean, and they often need to cope with the stress of reactive sulfur species, such as sulfide and sulfane sulfur. Sulfane sulfur refers to the various forms of zero-valent sulfur, including persulfide, polysulfide, and element sulfur (S₈). Although sulfane sulfur participates in signaling transduction and resistance to reactive oxygen species in cyanobacteria, it is toxic at high concentrations and induces sulfur stress, which has similar effects to oxidative stress. In this study, we report that Synechococcus sp. PCC7002 uses peroxiredoxin to cope with the stress of cellular sulfane sulfur. Synechococcus sp. PCC7002 contains six peroxiredoxins, and all were induced by S₈. Peroxiredoxin I (PrxI) reduced S₈ to H₂S by forming a disulfide bond between residues Cys⁵³ and Cys¹⁵³ of the enzyme. A partial deletion strain of Synechococcus sp. PCC7002 with decreased copy numbers of the prxI gene was more sensitive to S₈ than was the wild type. Thus, peroxiredoxin is involved in maintaining the homeostasis of cellular sulfane sulfur in cyanobacteria. Given that peroxiredoxin evolved before the occurrence of O₂ on Earth, its original function could have been to cope with reactive sulfur species stress, and that function has been preserved. IMPORTANCE Cyanobacteria are the earliest microorganisms that perform oxygenic photosynthesis, which has played a key role in the evolution of life on Earth, and they are the most important primary producers in the modern oceans. The cyanobacterium Synechococcus sp. PCC7002 uses peroxiredoxin to reduce high levels of sulfane sulfur. That function is possibly the original role of peroxiredoxin, as the enzyme evolved before the appearance of O₂ on Earth. The preservation of the reduction of sulfane sulfur by peroxiredoxin5-type peroxiredoxins may offer cyanobacteria an advantage in the complex environment of the modern oceans.

Myrica salicifolia Hochst. ex A. Rich. suppress acetic acid-induced ulcerative colitis in rats by reducing TNF-alpha and interleukin-6, oxidative stress parameters and improving mucosal protection

Ulcerative colitis (UC) is an inflammatory bowel disease (IBD) with rising prevalence in developing countries, and limited success of current therapies, natural products have immense potential for therapy due to their "disease modifying and side-effect neutralizing" potential. Myrica salicifolia is traditionally used for gastrointestinal diseases and have reported antiinflammatory activities, but its use in IBD has not yet been studied. Therefore, in the present study, the effects of the root extract of M. salicifolia (Ms.Cr) were investigated using the acetic acid-induced UC model in rats. For 6 days, the rats were given either vehicle (10 mL/kg), lower (200 mg/kg), and higher (400 mg/kg) doses of Ms.Cr, or the positive control drug (prednisolone; 2 mg/kg) orally. A single dosage of 5% acetic acid (1.0 mL) was administered intrarectally to rats on day 6 to induce UC. Disease activity index (DAI), histological observations, the biochemical parameters related to oxidative stress, and specific cytokines such as interleukin-6 (IL-6) and the tumor necrosis factor-α (TNF-α) were determined to assess the effect of Ms.Cr. In comparison to the AA-induced colitis rats, Ms.Cr's pretreatment significantly decreased DAI, colonic ulceration, and inflammatory score. Total glutathione levels and catalase activity were considerably recovered in the colitis group treated with Ms.Cr, whereas enhanced lipid peroxidation in colon tissues was significantly decreased. Moreover, Ms.Cr pretreatment also caused inhibition of the activation of IL-6 and TNF-α in the colonic tissues of respective groups. Based on these findings, Ms.Cr might be developed to treat UC in the future.

Antioxidant activity of Far Eastern bivalves in their natural habitat

The activities of the key antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GP) and glutathione reductase (GR) as well as levels of reduced glutathione (GSH) and integral antioxidant activity (IAA), were studied in the digestive glands and gills of 14 bivalve species. Species and tissue differences of the antioxidant (AO) systems of the investigated mollusks were discussed in connection with their physiological and biochemical peculiarities. This article describes the role of the AO system of mollusks in adaptation to natural habitat conditions and shows the relationship of AO activity with the maximum habitat depth (MHD) and maximum lifespan (MLS) of these species.

A Synthetic SOD/Catalase Mimic Compound for the Treatment of ALS

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease affecting motor neurons. To date, the etiology of the disease is still unclear, with evidence of reactive oxygen species, mitochondrial dysfunction, iron homeostasis perturbation, protein misfolding and protein aggregation as key players in the pathology of the disease. Twenty percent of familial ALS and two percent of sporadic ALS instances are due to a mutation in Cu/Zn superoxide dismutase (SOD1). Sporadic and familial ALS affects the same neurons with similar pathology; therefore, the underlying hypothesis is that therapies effective in mutant SOD1 models could be translated to sporadic ALS. Corrole metal complexes have lately been identified as strong and potent catalytic antioxidants with beneficial effects in oxidative stress-related diseases such as Parkinson's disease, Alzheimer's disease, atherosclerosis, diabetes and its complications. One of the most promising candidates is the iron complex of an amphiphilic corrole, 1-Fe. In this study we used the SOD1 G93R mutant zebrafish ALS model to assess whether 1-Fe, as a potent catalytic antioxidant, displays any therapeutic merits in vivo. Our results show that 1-Fe caused a substantial increase in mutant zebrafish locomotor activity (up to 30%), bringing the locomotive abilities of the mutant treated group close to that of the wild type untreated group (50% more than the mutated untreated group). Furthermore, 1-Fe did not affect WT larvae locomotor activity, suggesting that 1-Fe enhances locomotor ability by targeting mechanisms underlying SOD1 ALS specifically. These results may pave the way for future development of 1-Fe as a viable treatment for ALS.

The DUG Pathway Governs Degradation of Intracellular Glutathione in Aspergillus nidulans

Glutathione (GSH) is an abundant tripeptide that plays a crucial role in shielding cellular macromolecules from various reactive oxygen and nitrogen species in fungi. Understanding GSH metabolism is of vital importance for deciphering redox regulation in these microorganisms. In the present study, to better understand the GSH metabolism in filamentous fungi, we investigated functions of the dugB and dugC genes in the model fungus Aspergillus nidulans These genes are orthologues of dug2 and dug3, which are involved in cytosolic GSH degradation in Saccharomyces cerevisiae The deletion of dugB, dugC, or both resulted in a moderate increase in the GSH content in mycelia grown on glucose, reduced conidium production, and disturbed sexual development. In agreement with these observations, transcriptome data showed that genes encoding mitogen-activated protein (MAP) kinase pathway elements (e.g., steC, sskB, hogA, and mkkA) or regulatory proteins of conidiogenesis and sexual differentiation (e.g., flbA, flbC, flbE, nosA, rosA, nsdC, and nsdD) were downregulated in the ΔdugB ΔdugC mutant. Deletion of dugB and/or dugC slowed the depletion of GSH pools during carbon starvation. It also reduced accumulation of reactive oxygen species and decreased autolytic cell wall degradation and enzyme secretion but increased sterigmatocystin formation. Transcriptome data demonstrated that enzyme secretions-in contrast to mycotoxin production-were controlled at the posttranscriptional level. We suggest that GSH connects starvation and redox regulation to each other: cells utilize GSH as a stored carbon source during starvation. The reduction of GSH content alters the redox state, activating regulatory pathways responsible for carbon starvation stress responses.IMPORTANCE Glutathione (GSH) is a widely distributed tripeptide in both eukaryotes and prokaryotes. Owing to its very low redox potential, antioxidative character, and high intracellular concentration, GSH profoundly shapes the redox status of cells. Our observations suggest that GSH metabolism and/or the redox status of cells plays a determinative role in several important aspects of fungal life, including oxidative stress defense, protein secretion, and secondary metabolite production (including mycotoxin formation), as well as sexual and asexual differentiations. We demonstrated that even a slightly elevated GSH level can substantially disturb the homeostasis of fungi. This information could be important for development of new GSH-producing strains or for any biotechnologically relevant processes where the GSH content, antioxidant capacity, or oxidative stress tolerance of a fungal strain is manipulated.

Studying the Ability of Thymol to Improve Fungicidal Effects of Tebuconazole and Difenoconazole Against Some Plant Pathogenic Fungi in Seed or Foliar Treatments

Thymol, a secondary plant metabolite possessing antifungal and chemosensitizing activities, disrupts cell wall or membrane integrity and interferes with ergosterol biosynthesis. Thymol also functions as a redox-active compound inducing generation of reactive oxygen species and lipid peroxidation in fungal cells. Previously, we showed thymol significantly enhanced the in vitro growth inhibitory effect of difenoconazole against Bipolaris sorokiniana and Parastagonospora nodorum. More recently, we demonstrated a possibility to use thymol to overcome the resistance of a P. nodorum strain able to grow on difenoconazole-containing media. However, potential for thymol to serve as a chemosensitizing agent in seed or plant treatments, to provide an effective suppression of the above-mentioned plant pathogens by triazole fungicides applied in lowered dosages, had yet to be tested. In the work presented here, we showed combined treatments of naturally infected barley seeds with thymol and difenoconazole (Dividend® 030 FS) synergistically exacerbated the protective effect against common root rot agent, B. sorokiniana, and other fungi (Fusarium spp. and Alternaria spp.). Similarly, co-applied treatment of wheat seeds, artificially inoculated with Fusarium culmorum, resulted in equivalent reduction of disease incidence on barley seedlings as application of Dividend®, alone, at a ten-fold higher dosage. In foliar treatments of wheat seedlings, thymol combined with Folicur® 250 EC (a.i. tebuconazole) enhanced sensitivity of P. nodorum, a glume/leaf blotch pathogen, to the fungicide and provided a significant mitigation of disease severity on treated seedlings, compared to controls, without increasing Folicur® dosages. Folicur® co-applied with thymol was also significantly more effective against a strain of P. nodorum tolerant to Folicur® alone. No additional deoxynivalenol or zearalenone production was found when a toxigenic F. culmorum was cultured in a nutrient medium containing thymol at a concentration used for chemosensitization of root rot agents. Accordingly, F. culmorum exposure to thymol at the sensitizing concentration did not up-regulate key genes associated with the biosynthesis of trichothecene or polyketide mycotoxins in this pathogen. Further studies using field trials are necessary to determine if thymol-triazole co-applications result in sensitization of seed- and foliar-associated plant pathogenic fungi, and if thymol affects production of fusarial toxins under field conditions.

Study of the relationship between extracellular superoxide and glutathione production in batch cultures of Escherichia coli

Aerobically growing Escherichia coli generates superoxide flux into the periplasm via the oxidation of dihydromenaquinone and simultaneously carries out continuous transmembrane cycling of glutathione (GSH). Here we have shown that, under the conditions of a gradual decrease in dissolved oxygen (dO₂), characteristic of batch culture, the global regulatory system ArcB/ArcA can play an important role in the coordinated control of extracellular superoxide and GSH fluxes and their interaction with intracellular antioxidant systems. The lowest superoxide production was observed in the menA and arcB mutants, while the atpA, atpC and atpE mutants generated superoxide 1.3-1.5 times faster than the parent. The share of exported glutathione in the ubiC, atpA, atpC, and atpE mutants was 2-3 times higher compared to the parent. A high direct correlation (r = 0.87, p = 0.01) between extracellular superoxide and GSH was revealed. The menA and arcB mutants, as well as the cydD mutant lacking the GSH export system CydDC, were not capable of GSH excretion with a decrease in dO₂, which indicates a positive control of GSH export by ArcB. In contrast, ArcB downregulates sodA, therefore, an inverse correlation (r = -0.86, p = 0.013) between superoxide production and sodA expression was observed.

Intracellular Mechanisms of Oxygen Sensing

The review describes molecular mechanisms for sensing oxygen levels in various compartments of animal cell. Several pathways for intracellular oxygen sensing are discussed together with details of functioning of the near-membrane and cytoplasmic pools of molecular components in hypoxic cells. The data on the role of mitochondria in cell sensitivity to a decreased oxygen content are presented. Details of mutual influence of the operational and chronic intracellular mechanisms for detecting the negative gradients of molecular oxygen concentration and their relationship with cell metabolism response to the oxidative stress are discussed.

Glucose: Sweet or bitter effects in plants-a review on current and future perspective

Sugars are metabolic substrates playing a part in modulating various processes in plants during different phases of development. Thus, modulating the sugar metabolism can have intense effects on the plant metabolism. Glucose is a soluble sugar, found throughout the plant kingdom. Apart from being a universal carbon source, glucose also operates as a signaling molecule modulating various metabolic processes in plants. From germination to senescence, wide range of processes in plants is regulated by glucose. The effect of glucose is found to be concentration dependent. Photosynthesis and its related attributes, respiration and nitrogen metabolism are influenced by glucose application. Endogenous content of glucose increases upon exposure of plant to various abiotic stresses and also when glucose is supplied exogenously. Glucose accumulation alleviates the damaging effects of stress by enhancing production of antioxidants and compounds similar to that of photosynthetic CO₂ fixation which act as an osmoticum by maintaining osmotic pressure inside the cell, pH homeostasis regulator and reduce membrane permeability during stress. Glucose interaction with various phytohormones has also been discussed in this review.

Proline-containing peptides-New insight and implications: A Review

The family of regulatory proline-containing peptides (PCPs), also known as glyprolines, exhibit significant biological activity. The group of glyprolines includes Gly-Pro (GP), Pro-Gly-Pro (PGP), cyclic Gly-Pro (cGP), as well as PGP derivatives, for example, N-acetylated PGP (N-a-PGP) and N-methylated PGP (N-m-PGP). PCPs are engaged in various biological processes including the proinflammatory neutrophil chemoattraction in lung diseases, inflammatory bowel diseases or ischemic stroke. Glyprolines have been also postulated to play an important role as atheroprotective and anticoagulant agents, exhibit neuroprotective effects in Parkinson's disease, as well as regulate insulin-like growth factor (IGF) homeostasis. It was also noticed that PCPs inhibit proliferation and migration of keratinocytes in wound healing, protection of the gastric mucosa and stimulation of its regeneration. The regulatory glyprolines are derived from endogenous and exogenous sources. Most PCPs are derived from collagen or diet protein degradation. Recently, great interest is concentrated on short proline-rich oligopeptides derived from IGF-1 degradation. The mechanism of PCPs biological activity is not fully explained. It involves receptor-mediated mechanisms, for example, N-a-PGP acts as CXCR1/2 receptor ligand, whereas cGP regulates IGF-1 bioavailability by modifying the IGF-1 binding to the IGF-1 binding protein-3. PGP has been observed to interact with collagen-specific receptors. The data suggest a promising role of PGP as a target of various diseases therapy. This review is focused on the effect of PCPs on metabolic processes in different tissues and the molecular mechanism of their action as an approach to pharmacotherapy of PCPs-dependent diseases.

Heat Stress in Legume Seed Setting: Effects, Causes, and Future Prospects

Grain legumes provide a rich resource of plant nutrition to human diets and are vital for food security and sustainable cropping. Heat stress during flowering has a detrimental effect on legume seed yield, mainly due to irreversible loss of seed number. To start with, we provide an overview of the developmental and physiological basis of controlling seed setting in response to heat stress. It is shown that every single process of seed setting including male and female gametophyte development, fertilization, and early seed/fruit development is sensitive to heat stress, in particular male reproductive development in legume crops is especially susceptible. A series of physiochemical processes including heat shock proteins, antioxidants, metabolites, and hormones centered with sugar starvation are proposed to play a key role in regulating legume seed setting in response to heat stress. The exploration of the molecular mechanisms underlying reproductive heat tolerance is in its infancy. Medicago truncatula, with a small diploid genome, and well-established transformation system and molecular platforms, has become a valuable model for testing gene function that can be applied to advance the physiological and molecular understanding of legume reproductive heat tolerance.

Redox-Responsive Fluorescent Polycarbonates Based on Selenide for Chemotherapy of Triple-Negative Breast Cancer

Transient increase of reactive oxygen species (ROS) is vital for some physiological processes, whereas the chronic and sustained high ROS level is usually implicated in the inflammatory diseases and cancers. Herein, we report the innovative redox-responsive theranostic micellar nanoparticles that are able to load anticancer drugs through coordination and hydrophobic interaction and to fluorescently monitor the intracellular redox status. The nanoparticles were formed by the amphiphilic block copolymers composed of a PEG segment and a selenide-containing hydrophobic polycarbonate block with a small fraction of coumarin-based chromophore. Under the alternative redox stimulation that might be encountered in the physiological process of some healthy cells, these nanoparticles underwent the reversible changes in size, morphology, and fluorescence intensity. With the assistance of small model compounds, we clarified the chemistry behind these changes, that is, the redox triggered reversible transformation between selenide and selenoxide. Upon the monotonic oxidation similar to the sustained high ROS level of cancer cells, the nanoparticles could be disrupted completely, which was accompanied by the drastic decrease in fluorescence. Cisplatin and paclitaxel were simultaneously coloaded in the nanoparticles with a moderate efficacy, and the coordination between selenide and platinum improved the stability of the drug-loaded nanoparticles against dilution. The naked nanoparticles are cytocompatible, whereas the dual drug-loaded nanoparticles exhibited a concentration dependent and synergistic cytotoxicity to triple-negative breast cancer (TNBC) cells. Of importance, the drug-loaded nanoparticles are much more toxic to TNBC cells than to normal cells due in part to ROS overproduction in the former cell lines.

Zebrafish fin-derived fibroblast cell line: A model for in vitro wound healing

The goal of this study was to develop and characterize a cell line from the caudal fin tissue of zebrafish and also its application as an in vitro model to study the effect of H₂ O₂ in wound healing. Fibroblastic cell line was developed using explant culture method from caudal fin tissue of zebrafish and characterized. This cell line was named as DrF cell line. The DrF cells treated with 0-10 µM/ml H₂ O₂ were tested for viability, proliferation and motility by MTT assay, trypan blue assay and chemotaxis assay, respectively. Among the different concentrations of H₂ O₂ , 4 µM was found to be nontoxic to study cell migration in in vitro scratch wound assay. Furthermore, the expression of proliferating cell nuclear antigen (PCNA) and chemokine receptor (CXCR4) genes was carried by qPCR. The cell survival, proliferation and migration were extremely enriched at 4 µM level of H₂ O₂ . We observed accelerated wound closure in DrF cells treated with H₂ O_2. The qPCR results indicated that H₂ O₂ markedly up-regulated mRNA expression of PCNA and CXCR4. The findings from our study suggest that H₂ O₂ at low levels promotes cell survival, proliferation, migration and wound healing in DrF cells.

Anti-oxidant and anti-inflammatory effects of cinnamaldehyde and eugenol on mononuclear cells of rheumatoid arthritis patients

Rheumatoid arthritis (RA) is an autoimmune disorder affecting joints and frequently characterized by initial local and later systemic inflammation. The present study was conducted with the aim to determine the anti-inflammatory and antioxidant effects of cinnamaldehyde and eugenol in the peripheral blood mononuclear cells (PBMC) of RA patients. PBMCs obtained from RA patients were treated with varying concentrations of cinnamaldehyde and eugenol. The levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were monitored in the 24-h culture supernatant of PBMCs. Reactive oxygen species formation, biomolecular oxidation and the activities of antioxidant enzymes were also determined. FTIR analysis was done to determine structural alterations in the PBMCs. Molecular docking was performed to gain an insight into the binding mechanism of eugenol and cinnamaldehyde with pro-inflammatory cytokines. The levels of pro-inflammatory cytokines and markers of oxidative stress were found to be elevated in the PBMC culture of RA patients as compared to the healthy controls. Cinnamaldehyde and eugenol have significantly reduced the levels of cytokines. Reactive oxygen species formation, biomolecular oxidation and antioxidant defense response were also ameliorated by treating PBMCs with both the compounds. FTIR results further confirms cinnamaldehyde and eugenol mediated protection to biomolecules of PBMCs of RA patients. Molecular docking results indicates interaction of cinnamaldehyde and eugenol with key residues of TNF-α and IL-6. Cinnamaldehyde and eugenol were found to exert potent anti-inflammatory and anti-oxidant effects on the PBMC culture of RA patients. So, these compounds may be used as an adjunct in the management of RA.

The Influence of Oxidative Stress and Natural Antioxidants on Morphometric Parameters of Red Blood Cells, the Hemoglobin Oxygen Binding Capacity, and the Activity of Antioxidant Enzymes

Using a wide range of different physical and chemical methods, it was found that the oxidative stress caused by addition of hydrogen peroxide to the incubation medium has a significant effect on the conformation of haematoporphyrin, influencing the oxygen-binding properties of haemoglobin in red blood cells. Morphofunctional characteristics of red blood cells change; in particular, we have observed the transformation of erythrocytes, their transition into echinocytes. In erythrocytes, in response to increased lipid peroxidation (LPO) antioxidant enzymes become active. The use of natural antioxidants (β-carotene and resveratrol) works towards reducting the level of oxidative processes. Resveratrol has the greatest antioxidant effect.

Atheroprotective effect of novel peptides from Porphyridium purpureum in RAW 264.7 macrophage cell line and its molecular docking study

OBJECTIVE

To explore the atherogenic foam cell prevention efficiency of two dipeptides purified from Porphyridium purpureum on RAW 264.7 cell line and to study its molecular interaction through molecular docking.

RESULT

P. purpureum consists of 29.9% protein and 2.98% phycoerythrin on a dry weight basis. The two dipeptides namely of Histidine-Glutamic acid (HE) and Glycine-Proline (GP) isolated from the total protein and purified phycoerythrin of P. purpureum respectively, were evaluated for atherogenic foam cell prevention capacity in RAW 264.7 cell line. The IC_5O values of peptides were found to be 91.2 ± 1.81 µg/ml (GP), 103.3 ± 4.8 µg/ml (HE) in MTT assay. The two peptides reduce the foam cell formation, intracellular lipid accumulation (cholesterol and triglycerides) and the secretion of TNF-α and IL-6 which are inflammatory cytokines in RAW 264.7 cell line at non-cytotoxic concentrations. A molecular interaction study proposed the binding pose for GP and HE peptides targeting the scavenging receptors CD36, SRA1, and Map Kinase p38 (a protein mediator).

CONCLUSIONS

The cell line and molecular docking study indicated that among the two dipeptides, peptide GP has the highest atherogenic foam cell prevention efficiency.

Analysis of IL17A and IL21 Expression in the Small Intestine of Celiac Disease Patients and Correlation with Circulating Thioredoxin Level

AIMS

Th17 cells and their related cytokines play an important role in the pathogenesis of celiac disease (CD), and thioredoxin (Trx) is an extracellular TG2 activity regulator. This study evaluated Trx serum levels and the expression levels of IL17A, IL21, and Trx genes in biopsies of treated (gluten-free diet) and naïve (untreated) CD patients compared with healthy individuals.

METHODS

Duodenal biopsies were collected from treated CD patients (n = 60), healthy controls (n = 60), and eight newly diagnosed celiac patients. IL17A, IL21, and Trx gene expression was assessed by quantitative polymerase chain reaction (qPCR) and compared with serum Trx levels assessed by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Expression levels of the IL21 and Trx genes were not significantly modulated in the CD group compared to the control group, whereas the IL17A gene in CD patients was transcribed at significantly higher levels among the CD group. Serum concentrations of Trx were significantly increased in treated CD patients compared to the control group.

CONCLUSIONS

We observed that IL17A gene is more highly expressed in duodenal biopsies of CD patients than controls, and that the serum levels of Trx are significantly higher in treated CD patients than controls. Therefore, the expression levels of these genes and gene products, respectively, could potentially be used as diagnostic biomarkers for CD patients, although more studies are needed to unravel the underlying molecular mechanisms.

Phylogenetic and environmental components of inter-specific variability in the antioxidant defense system in freshwater anomurans Aegla (Crustacea, Decapoda)

The antioxidant defense system (ADS) protects organisms against the potential oxidative stress induced by environmental features, underlying processes of habitat diversification. The anomurans Aegla constitute the most threatened freshwater decapods of South America, occupying pristine habitats with narrow distribution. Using phylogenetic comparative methods, we addressed: Is the variability of habitat physicochemical parameters and tissue ADS phylogenetically structured? How do environmental features correlate with ADS? How do they vary among species? Several physicochemical parameters of water, as well as metals in sediments, were measured in ten aeglid species' habitats. Additionally, metal accumulation and ADS parameters [metallothionein-like proteins (MTLP), antioxidant capacity against peroxyl radicals (ACAP), and glutathione system (GSH-GSSG)] were evaluated in hepatopancreas. Water conductivity and pH showed phylogenetic signal, while all other physicochemical traits demonstrated plastic variability. Metals were present at natural concentrations, which are corroborated by the relative stable GSH/GSSG ratio, and by their absence of correlation with bioaccumulation levels and MTLP, both phylogenetically structured. However, metal variability across species' niches is associated with ACAP, a potential biomarker tool. Thus, the physiological sensitivity of aeglids is environmentally driven but also  phylogenetically constrained, unraveling the importance of systematic framework for cross-species investigations and future monitoring strategies of these conspicuous freshwater animals.

Reactive Oxygen Species Mediated Prostaglandin E2 Contributes to Acute Response of Epithelial Injury

Reactive oxygen species (ROS) generated after tissue injury play a crucial role during wound healing through initiating acute inflammation, clarifying infection and dead tissue, and mediating various intracellular signal transduction. Prostaglandin E₂ (PGE₂) has been identified as one of the major factors responsible for inflammation and tissue repair. In this study, we tested our hypothesis that ROS produced by damaged human keratinocytes induces the synthesis of PGE₂. In vitro epithelial wounding model was used to observe the production of ROS and secretion of PGE₂ as well as the involved signal pathway. The mechanical injury caused the rapid production of ROS in in vitro cultured keratinocytes, which was significantly blocked by an inhibitor of nicotinamide adenine dinucleotide phosphate oxidase. The increased intracellular ROS caused by mechanical injury stimulates PGE₂ production in a time-dependent manner via the activation of cyclooxygenase-2 (COX-2), which was stimulated by phosphorylation of extracellular signal-regulated protein kinase (ERK). These results indicate ROS-induced ERK activation leading to the activation of COX-2 and the synthesis of PGE₂ in human keratinocytes responding to mechanical injury in the acute phase.

Electronic control of gene expression and cell behaviour in Escherichia coli through redox signalling

The ability to interconvert information between electronic and ionic modalities has transformed our ability to record and actuate biological function. Synthetic biology offers the potential to expand communication ‘bandwidth' by using biomolecules and providing electrochemical access to redox-based cell signals and behaviours. While engineered cells have transmitted molecular information to electronic devices, the potential for bidirectional communication stands largely untapped. Here we present a simple electrogenetic device that uses redox biomolecules to carry electronic information to engineered bacterial cells in order to control transcription from a simple synthetic gene circuit. Electronic actuation of the native transcriptional regulator SoxR and transcription from the PsoxS promoter allows cell response that is quick, reversible and dependent on the amplitude and frequency of the imposed electronic signals. Further, induction of bacterial motility and population based cell-to-cell communication demonstrates the versatility of our approach and potential to drive intricate biological behaviours.

Synthetic biology offers the ability to explore new ways of manipulating gene expression and function. Here the authors demonstrate an electrogenetic device that allows control of transcription by an exogenous electrical signal.

Calcium, Reactive Oxygen Species, and Synaptic Plasticity

In this review article, we address how activity-dependent Ca2+ signaling is crucial for hippocampal synaptic/structural plasticity and discuss how changes in neuronal oxidative state affect Ca2+ signaling and synaptic plasticity. We also analyze current evidence indicating that oxidative stress and abnormal Ca2+ signaling contribute to age-related synaptic plasticity deterioration.

Traditional Chinese medicine Qili qiangxin inhibits cardiomyocyte apoptosis in rats following myocardial infarction

The aim of the present study was to examine the effect of the traditional Chinese medicine Qili qiangxin on cardiomyocyte apoptosis following myocardial infarction (MI) in a rat model. MI was induced in rats by ligation of the anterior descending coronary artery. Survivors were randomly divided into the sham operation, MI, and Qili qiangxin groups (4 g/kg per day). After 28 days, infarction size was measured. In the non-infarcted zones (NIZ), the apoptotic index (AI) was measured by terminal deoxynucleotidyl transferase (TdT)-mediated digoxigenin-conjugated dUTP nick-end labeling (TUNEL). Expression of Fas was detected by immunohistochemistry, and the expression of xanthine oxidase (XO) and caspase-3 by western blot analysis. In addition, the XO and ^·O₂⁻, ^·OH-scavenging activity of myocardial tissue in NIZ was measured by colorimetry. Compared to the MI group, AI and the expression of Fas and caspase-3 were significantly decreased in NIZ. The activity of XO was also considerably reduced while ^·O₂⁻ and ^·OH-scavenging activity was significantly increased in the Qili qiangxin group. Ventricular remodeling was attenuated but there were no significant differences in infarct size (IS) or XO expression levels between the Qili qiangxin and MI groups. In conclusion, the results suggest that Qili qiangxin may inhibit cardiomyocyte apoptosis in NIZ in rats. The potential mechanism involved may be associated with its ability to reduce reactive oxygen species (ROS) and to depress the expression of Fas and caspase-3.

Chemical profile and antioxidant capacity verification of Psidium guajava (Myrtaceae) fruits at different stages of maturation

Psidium guajava (Myrtaceae), a common plant in Cariri region, Ceara, Brazil, as well as in various parts of the world, contains high concentrations of bioactive compounds and in many communities its parts are used for therapeutic purposes. Studies describe antioxidant, antimicrobial and anti-diarrheal actions from extracts obtained from leaves, but information about the activities of the fruits and comparison of these at different maturity stages (immature, partially mature and mature) are scarce. This study aims to evaluate the antioxidant properties by quantifying the levels of phenolic and flavonoid compounds, carotenoids and vitamin C of P. guajava fruits at different stages of maturation. The content of phenolic compounds for the immature fruit, partially mature and mature were: 22.41; 34.61 and 32.92 mg of AG/g fraction. The flavonoid content for immature fruits, intermediate and mature were: 2.83; 5.10 and 5.65 mg RUT/g fraction, respectively. Following the same standards of maturation stages, the ascorbic acid content was determined with values of 0.48; 0.38 and 0.21 mg AA/g fraction, respectively. HPLC analysis identified and quantified the presence of gallic acid, catechin, chlorogenic acid, caffeic acid, epicatechin, rutin, quercitrin, isoquercitrin, quercetin, kaempferol, glycosylated campeferol, tocopherol, β-carotene and lycopene. The antioxidant activity carried out by DPPH method showed the mature fruits bearing the best results, whereas chelation of Fe2+ ions showed higher percentage for the immature fruit. The results obtained by lipidic peroxidation were not satisfactory.

Improvement of antioxidant status after Brazil nut intake in hypertensive and dyslipidemic subjects

OBJECTIVES

To investigate the effect of partially defatted Granulated Brazil nut (GBN) on biomarkers of oxidative stress and antioxidant status of hypertensive and dyslipidemic patients on nutrition and drug approaches.

METHODS

Ninety one hypertensive and dyslipidemic subjects of both genders (51.6 % men), mean age 62.1 ± 9.3 years, performed a randomized crossover trial, double-blind, placebo controlled. Subjects received a diet and partially defatted GBN 13 g per day (≈227.5 μg/day of selenium) or placebo for twelve weeks with four-week washout interval. Anthropometric, laboratory and clinic characteristics were investigated at baseline. Plasma selenium (Se), plasma glutathione peroxidase (GPx3) activity, total antioxidant capacity (TAC), 8-epi PGF2α and oxidized LDL were evaluated at the beginning and in the end of each intervention.

RESULTS

GBN intake significantly increased plasma Se from 87.0 ± 16.8 to 180.6 ± 67.1 μg/L, increased GPx3 activity in 24,8% (from 112.66 ± 40.09 to 128.32 ± 38.31 nmol/min/mL, p < 0,05), and reduced 3.25% of oxidized-LDL levels (from 66.31 ± 23.59 to 60.68 ± 20.88 U/L, p < 0.05). An inverse association between GPx3 and oxidized LDL levels was observed after supplementation with GBN by simple model (β -0.232, p = 0.032) and after adjustment for gender, age, diabetes and BMI (β -0.298, p = 0.008). There wasn't association between GPx3 and 8-epi PGF2α (β -0.209, p = 0.052) by simple model.

CONCLUSION

The partially defatted GBN intake has a potential benefit to increase plasma selenium, increase enzymatic antioxidant activity of GPx3 and to reduction oxidation in LDL in hypertensive and dyslipidemic patients.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT01990391; November 20, 2013.

Multibiomarker assessment of cerium dioxide nanoparticle (nCeO2) sublethal effects on two freshwater invertebrates, Dreissena polymorpha and Gammarus roeseli

Cerium nanoparticles (nCeO2) are widely used in everyday products, as fuel and paint additives. Meanwhile, very few studies on nCeO2 sublethal effects on aquatic organisms are available. We tried to fill this knowledge gap by investigating short-term effects of nCeO2 at environmentally realistic concentrations on two freshwater invertebrates; the amphipod Gammarus roeseli and the bivalve Dreissena polymorpha, using an integrated multibiomarker approach to detect early adverse effects of nCeO2 on organism biology. Differences in the behaviour of the organisms and of nanoparticles in the water column led to differential nCeO2 bioaccumulations, G. roeseli accumulating more cerium than D. polymorpha. Exposure to nCeO2 led to decreases in the size of the lysosomal system, catalase activity and lipoperoxidation in mussel digestive glands that could result from nCeO2 antioxidant properties, but also negatively impacted haemolymph ion concentrations. At the same time, no strong adverse effects of nCeO2 could be observed on G. roeseli. Further experiments will be necessary to confirm the absence of severe nCeO2 adverse effects in long-term environmentally realistic conditions.

Dual effect of oxidative stress on leukemia cancer induction and treatment

Oxidative stress (OS) has been characterized by an imbalance between the production of reactive oxygen species (ROS) and a biological system's ability to repair oxidative damage or to neutralize the reactive intermediates including peroxides and free radicals. High ROS production has been associated with significant decrease in antioxidant defense mechanisms leading to protein, lipid and DNA damage and subsequent disruption of cellular functions. In humans, OS has been reported to play a role in the pathogenesis of neurodegenerative diseases such as Alzheimer's disease, Huntington's disease, Lou Gehrig's disease, multiple sclerosis and Parkinson's disease, as well as atherosclerosis, autism, cancer, heart failure, and myocardial infarction. Although OS has been linked to the etiology and development of chronic diseases, many chemotherapeutic drugs have been shown to exert their biologic activity through induction of OS in affected cells. This review highlights the controversial role of OS in the development and progression of leukemia cancer and the therapeutic application of increased OS and antioxidant approaches to the treatment of leukemia patients.

Nonthermal atmospheric pressure plasma enhances mouse limb bud survival, growth, and elongation

The enhanced differentiation of mesenchymal cells into chondrocytes or osteoblasts is of paramount importance in tissue engineering and regenerative therapies. A newly emerging body of evidence demonstrates that appendage regeneration is dependent on reactive oxygen species (ROS) production and signaling. Thus, we hypothesized that mesenchymal cell stimulation by nonthermal (NT)-plasma, which produces and induces ROS, would (1) promote skeletal cell differentiation and (2) limb autopod development. Stimulation with a single treatment of NT-plasma enhanced survival, growth, and elongation of mouse limb autopods in an in vitro organ culture system. Noticeable changes included enhanced development of digit length and definition of digit separation. These changes were coordinated with enhanced Wnt signaling in the distal apical epidermal ridge (AER) and presumptive joint regions. Autopod development continued to advance for approximately 144 h in culture, seemingly overcoming the negative culture environment usually observed in this in vitro system. Real-time quantitative polymerase chain reaction analysis confirmed the up-regulation of chondrogenic transcripts. Mechanistically, NT-plasma increased the number of ROS positive cells in the dorsal epithelium, mesenchyme, and the distal tip of each phalange behind the AER, determined using dihydrorhodamine. The importance of ROS production/signaling during development was further demonstrated by the stunting of digital outgrowth when anti-oxidants were applied. Results of this study show NT-plasma initiated and amplified ROS intracellular signaling to enhance development of the autopod. Parallels between development and regeneration suggest that the potential use of NT-plasma could extend to both tissue engineering and clinical applications to enhance fracture healing, trauma repair, and bone fusion.

Oxidation-responsive polymers for biomedical applications

This article summarizes recent progress in the design and synthesis of various oxidation-responsive polymers and their application in biomedical fields.

H2S signaling in redox regulation of cellular functions

Hydrogen sulfide (H2S) is traditionally recognized as a toxic gas with a rotten-egg smell. In just the last few decades, H2S has been found to be one of a family of gasotransmitters, together with nitric oxide and carbon monoxide, and various physiologic effects of H2S have been reported. Among the most acknowledged molecular mechanisms for the cellular effects of H2S is the regulation of intracellular redox homeostasis and post-translational modification of proteins through S-sulfhydration. On the one side, H2S can promote an antioxidant effect and is cytoprotective; on the other side, H2S stimulates oxidative stress and is cytotoxic. This review summarizes our current knowledge of the antioxidant versus pro-oxidant effects of H2S in mammalian cells and describes the Janus-faced properties of this novel gasotransmitter. The redox regulation for the cellular effects of H2S through S-sulfhydration and the role of H2S in glutathione generation is also recapitulated. A better understanding of H2S-regualted redox homeostasis will pave the way for future design of novel pharmacological and therapeutic interventions for various diseases.

Regulation of fruit and seed response to heat and drought by sugars as nutrients and signals

A large body of evidence shows that sugars function both as nutrients and signals to regulate fruit and seed set under normal and stress conditions including heat and drought. Inadequate sucrose import to, and its degradation within, reproductive organs cause fruit and seed abortion under heat and drought. As nutrients, sucrose-derived hexoses provide carbon skeletons and energy for growth and development of fruits and seeds. Sugar metabolism can also alleviate the impact of stress on fruit and seed through facilitating biosynthesis of heat shock proteins (Hsps) and non-enzymic antioxidants (e.g., glutathione, ascorbic acid), which collectively maintain the integrity of membranes and prevent programmed cell death (PCD) through protecting proteins and scavenging reactive oxygen species (ROS). In parallel, sugars (sucrose, glucose, and fructose), also exert signaling roles through cross-talk with hormone and ROS signaling pathways and by mediating cell division and PCD. At the same time, emerging data indicate that sugar-derived signaling systems, including trehalose-6 phosphate (T6P), sucrose non-fermenting related kinase-1 (SnRK), and the target of rapamycin (TOR) kinase complex also play important roles in regulating plant development through modulating nutrient and energy signaling and metabolic processes, especially under abiotic stresses where sugar availability is low. This review aims to evaluate recent progress of research on abiotic stress responses of reproductive organs focusing on roles of sugar metabolism and signaling and addressing the possible biochemical and molecular mechanism by which sugars regulate fruit and seed set under heat and drought.

Gold nanoparticles and oxidative stress in the blue mussel, Mytilus edulis

Relatively little is known about how gold nanoparticles (GNP) might interact in vivo with aquatic organisms. Gold nanoparticles (GNP) of defined average diameter may be synthesized and used to challenge test organisms held in aquaria. The blue mussel, Mytilus edulis, is a popular sentinel species in environmental toxicology. This chapter describes how mussels exposed to GNP (average diameter ~5 nm) may be dissected and extracts of digestive gland can be analyzed for oxidative stress. Protein thiols are labeled with 5'-iodoacetamide-fluorescein (IAF), and proteins are separated in one-dimensional electrophoresis. After scanning for IAF-associated fluorescence, gels are stained with colloidal coomassie. A ratio of fluorescence to protein stain is calculated revealing that thiol oxidation increases with GNP treatment.

Proteomics in HepG2 hepatocarcinoma cells with stably silenced expression of PRDX1

Peroxiredoxin 1 (PRDX1) is a member of the peroxiredoxin family. Aberrant expression of PRDX1 has been described in various cancers. We investigated the significance of this up-regulation in non-challenged hepatocellularcarcinoma (HCC) cells by establishing a HepG2 cell line stably expressing a Prdx1 shRNA. Prdx1 silencing reversed, at least partially, the tumoural phenotype of HepG2 cells, resulting in morphological changes, delayed cell growth, down-regulation of transcripts for AFP, osteopontin and β-catenin and decreased γ-glutamyl transpeptidase activity, and oppositely up-regulation of transcripts for E-cadherin and proapoptotic proteins (BAX, CASP3) and increased alkaline phosphatase and CASP3 activities. Proteomic profiling identified 16 spots differentially expressed in Prdx1-silenced cells. Most of the variations involved the down-regulation of proteins with pivotal roles in cell proliferation and differentiation, in agreement with the observed phenotypic changes. We also investigated the effect of Prdx1 silencing on thiol protein oxidation. Proteins prone to reversible cysteine oxidation play major physiological functions. Notably, the down-regulation and altered redox status of key enzymes of carbohydrate and amino acid metabolism suggested a disturbance of the Warburg effect and glutamine utilization, two major pathways in the proliferation of tumour cells. Overall, these observations suggest that PRDX1 acts as a pro-cancer protein in HCC HepG2 cells.

Anthocyanins protect human endothelial cells from mild hyperoxia damage through modulation of Nrf2 pathway

The detrimental effects of high oxygen supplementation have been widely reported. Conversely, few is known about the effects of exposure to mild hyperoxic conditions, an interesting issue since the use of oxygen-enriched mixture is now increasingly used in clinical practice and especially for professional and recreational reasons. Our study investigated if in vitro exposure of human umbilical vein endothelial cells (HUVECs) to moderate hyperoxia (O2 32 %) induces cellular alterations, measured as changes in cell signaling pathways. Furthermore, by means of an ex vivo experimental model where human volunteers were used as bioreactors, we studied whether anthocyanin metabolites are able to protect HUVECs against mild hyperoxia-induced damage. We observed that the cytotoxic effect of mild hyperoxia came along with a significant decrease in nuclear accumulation of the transcription factor Nrf2, as well as in the expression of Nrf2-regulated antioxidant and cytoprotective genes. Furthermore, under normoxic conditions, anthocyanin metabolites appeared able to activate the Nrf2 pathway, through the involvement of specific kinases (ERK1/2); this adaptive effect may explain the protective effect observed in mild hyperoxia-exposed HUVECs following anthocyanin pretreatment. This study confirms that dietary anthocyanins and/or their metabolites can protect endothelial cells against mild hyperoxia-induced alterations acting as cell signaling modulators.