Acute Oxidative Stress Research Articles

Protective effect of vanillic acid in hydrogen peroxide-induced oxidative stress in D.Mel-2 cell line.

The overproduction of reactive oxygen species (ROS) causes oxidative stress, such as Hydrogen peroxide (H2O2). Acute oxidative stress is one of the main reasons for cell death. In this study, the antioxidant properties of vanillic acid- a polyphenolic compound was evaluated. Therefore, this study aims to check the effectiveness of vanillic acid in H2O2-induced oxidative stress in D. Mel-2 cell line. The efficacy was determined by biochemical tests to check the ROS production. The cytotoxicity of H2O2 and vanillic acid was checked by MTT assay. The DNA fragmentation was visualized by gel electrophoresis. Protein biomarkers of oxidative stress were analyzed by western blotting. The results depict a promising antioxidant effect of vanillic acid. The IC50 value of vanillic acid and H2O2 was found 250 μg/ml and 125 μg/ml, respectively. The catalase activity, SOF, GPx, and PC was seen less in H2O2 treated group compared with the control and vanillic acid treated group. However, the TBRAS activity was hight in H2O2 treated group. The effect of H2O2 on DNA fragmentation was high as compared with vanillic acid-treated cells. The protein expression of Hsp70, IL-6 and iNOS was seen significant in a vanillic acid-treated group as compared with H2O2 treated group. These results reinforce that at low concentration, vanillic acid could be used as an antioxidant agent in the food and pharmaceutical industries.

Comparative Acute Toxicity and Oxidative Stress Responses in Three Aquatic Species Exposed to Stannic Oxide Nanoparticles and Stannic Chloride.

We experimentally investigated the toxicity of stannic oxide nanoparticles (SnO2 NPs) to three freshwater species including Scenedesmus obliquus, Daphnia magna, and Danio rerio. To evaluate effect, toxicological impacts were compared to that of stannic chloride (SnCl4). Based on the actual concentration of Sn, SnO2 NPs suspensions inhibited growth of S. obliquus in a dose-dependent manner, demonstrating a median effect concentration of 2.28 ± 0.53mg/L. However, SnO2 NP suspensions were found to exhibit limited acute toxicity in D. magna and D. rerio. Moreover, the toxicity of the SnO2 NP suspension was lower than SnCl4 for all three trophic aquatic organisms. Comparison of component-specific contribution to overall toxicity indicated that, in SnO2 NP suspensions, particulate Sn more significantly contributed to toxicity than dissolved Sn-ions. Furthermore, we found that the toxic mechanism of the SnO2 NP suspension involved the induction of oxidative stress by increasing intracellular ROS accumulation.

Protective effects of rare earth lanthanum on acute ethanol-induced oxidative stress in mice via Keap 1/Nrf2/p62 activation

With the widespread application of rare earth elements (REEs) in environment safety, food and medicine, they accumulate in the ecosystem and different human organs where REEs exert certain biological effects. Low dose REEs are proved to perform antioxidant effects, while high concentration can cause oxidative stress. However, scant information about rational doses and underlying mechanism of REEs as oxidants/antioxidants were illustrated. To elucidate these problems, here we performed a study that the ICR mice were received 0.1, 0.2, 1.0, 2.0 and 20.0 mg/kg lanthanum nitrate (La(NO3)3) by gavage for 30 days, and then were given 12 mL/kg ethanol once to undergo acute ethanol-induced oxidative stress. The antioxidant enzymes, antioxidants, peroxides and related proteins in Keap 1/Nrf2/p62 signaling pathway were measured. The results showed that La(NO3)3 inhibited hepatic morphological alternations by histopathological examination. Meanwhile, elevated superoxide dismutase (SOD) and glutathione (GSH), coupled with decreased alanine aminotransferase (ALT), aspartate aminotransferase (AST), malondialdehyde (MDA) and protein carbonyl (PC) were observed in serum and liver tissues of mice by enzyme-linked immunosorbent assay test. Furthermore, western blot analysis demonstrated that oxidative stress was alleviated due to enhanced NF-E2-related factor 2 (Nrf2) and phosphorylated p62 expressions as well as lower Kelch-like ECH-associated protein-1 (Keap 1), followed by the activation of heme oxygenase 1 (HO-1), NAD(P)H quinone oxidoreductase 1 (NQO-1) and glutamate cysteine ligase, catalytic (GCLC) proteins. Our findings clearly highlighted that La(NO3)3 could restore the redox homeostasis disrupted by ethanol through provoking Keap 1/Nrf2/p62 signaling pathway, and the optimal dosages were 1.0 and 2.0 mg/kg.

Peroxiredoxin 1 - Multifunctional antioxidant enzyme, protects from oxidative damages and increases the survival rate of mice exposed to total body irradiation

PurposePeroxiredoxin 1 (Prx1) is known to be a multifunctional antioxidant enzyme playing an essential role in protecting the organism against oxidative stress. We hypothesized that administration of exogenous recombinant Prx1 may provide additional protection of the mammalian organism during the development of acute oxidative stress induced by ionizing radiation. Hence, the aim of the present work was to study the radioprotective properties of exogenous Prx1. Materials and methodsRecombinant Prx1 was obtained by genetic engineering. The properties of Prx1 were studied using physicochemical methods. An immunoblotting and ELISA were used for the determination of the level of endogenous and exogenous Prx1 in animal blood. The survival rate of irradiated animals was assessed for 30 days with various modes of administration (intraperitoneal, intramuscular, intravenously) Prx1. Using a hematological analyzer and microscopic analysis, the changes in the level of leukocytes and platelets were assessed in animals that received and did not receive an intravenous injection of Prx1 before irradiation. Genoprotective properties of Prx1 were confirmed by micronucleus test. Real-time PCR was used to investigate the effect of Prx1 on the expression of genes involved in response to oxidative stress. ResultsRecombinant Prx1 was shown to significantly reduce oxidative damage to biological macromolecules. Prx1 is an effective radioprotector which decreases the severity of radiation-induced leuko- and thrombocytopenia, plus protects bone marrow cells from damage. The half-life of Prx1 in the bloodstream is more than 1 h, while within 1 h there is a loss of the antioxidant activity of Prx1 by almost 50%, which limits its use long (2 h) before irradiation. The introduction of Prx1 after irradiation has no significant radiomitigating effect. The most effective way of using Prx1 is intravenous administration shortly (15–30 min) before exposure to ionizing radiation, with a dose reduction factor of 1.3. Under the action of ionizing radiation a dose-dependent appearance of endogenous Prx1 in the bloodstream was also observed. The appearance of Prx1 in the bloodstream alters the expression of stress response genes (especial antioxidant response and DNA repair) in the cells of red bone marrow, promoting the activation of repair processes. ConclusionThe recombinant Prx1 can be considered as an effective radioprotector for minimizing the risks of injury of animal's body by ionizing radiation.

Proteomic signatures of acute oxidative stress response to paraquat in the mouse heart

The heart is sensitive to oxidative damage but a global view on how the cardiac proteome responds to oxidative stressors has yet to fully emerge. Using quantitative tandem mass spectrometry, we assessed the effects of acute exposure of the oxidative stress inducer paraquat on protein expression in mouse hearts. We observed widespread protein expression changes in the paraquat-exposed heart especially in organelle-containing subcellular fractions. During cardiac response to acute oxidative stress, proteome changes are consistent with a rapid reduction of mitochondrial metabolism, coupled with activation of multiple antioxidant proteins, reduction of protein synthesis and remediation of proteostasis. In addition to differential expression, we saw evidence of spatial reorganizations of the cardiac proteome including the translocation of hexokinase 2 to more soluble fractions. Treatment with the antioxidants Tempol and MitoTEMPO reversed many proteomic signatures of paraquat but this reversal was incomplete. We also identified a number of proteins with unknown function in the heart to be triggered by paraquat, suggesting they may have functions in oxidative stress response. Surprisingly, protein expression changes in the heart correlate poorly with those in the lung, consistent with differential sensitivity or stress response in these two organs. The results and data set here could provide insights into oxidative stress responses in the heart and avail the search for new therapeutic targets.

Acute Exercise-Induced Oxidative Stress Does Not Affect Immediate or Delayed Precursor Cell Mobilization in Healthy Young Males.

Exercise is known to acutely and transiently mobilize precursor cells to the peripheral blood. To date, the underlying mechanisms have not yet been fully elucidated and we hypothesized that exercise-induced oxidative stress could be a mobilizing agent, either directly or via circulating apoptotic cells as mediators. The aim of the study was to assess the effect of acute exercise-induced oxidative stress on numbers of circulating angiogenic precursor cells (CACs), circulating non-angiogenic precursor cells (nCACs), mesenchymal precursor cells (MPCs), mature endothelial cells (ECs), and mononuclear cells (MNCs), as well as their apoptotic subsets. Healthy, young males (n = 18, age: 24.2 ± 3.5 years) completed two identical, standardized incremental cycling tests. The first, un-supplemented control test was followed by a 7-day-long supplementation of vitamin C (1,000 mg/day) and E (400 I.U./day), immediately preceding the second test. Blood samples were collected before, directly after, 30, 90, 180, and 270 min after exercise, and aforementioned circulating cell numbers were determined by flow cytometry and a hematology analyzer. Additionally, total oxidative capacity (TOC) and total antioxidative capacity (TAC) were measured in serum at all timepoints. Antioxidative supplementation abolished the exercise-induced increase in the oxidative stress index (TOC/TAC), and reduced baseline concentrations of TOC and TOC/TAC. However, it did not have any effect on CACs, nCACs, and MPC numbers or the increase in apoptotic MNCs following exercise. Our results indicate that exercise-induced oxidative stress is neither a main driver of lymphocyte and monocyte apoptosis, nor one of the mechanisms involved in the immediate or delayed mobilization of precursor cells.

G protein-coupled receptor kinase 2 modifies the ability of Caenorhabditis elegans to survive oxidative stress.

Survival and adaptation to oxidative stress is important for many organisms, and these occur through the activation of many different signaling pathways. In this report, we showed that Caenorhabditis (C.) elegans G protein-coupled receptor kinases modified the ability of the organism to resist oxidative stress. In acute oxidative stress studies using juglone, loss-of-function grk-2 mutants were more resistant to oxidative stress compared with loss-of-function grk-1 mutants and the wild-type N2 animals. This effect was Ce-AKT-1 dependent, suggesting that Ce-GRK2 adjusted C. elegans oxidative stress resistance through the IGF/insulin-like signaling (IIS) pathway. Treating C. elegans with a GRK2 inhibitor, the selective serotonin reuptake inhibitor paroxetine, resulted in increased acute oxidative stress resistance compared with another selective serotonin reuptake inhibitor, fluoxetine. In chronic oxidative stress studies with paraquat, both grk-1 and grk-2 mutants had longer lifespan compared with the wild-type N2 animals in stress. In summary, this research showed the importance of both GRKs, especially GRK2, in modifying oxidative stress resistance.

WRN modulates translation by influencing nuclear mRNA export in HeLa cancer cells

BackgroundThe Werner syndrome protein (WRN) belongs to the RecQ family of helicases and its loss of function results in the premature aging disease Werner syndrome (WS). We previously demonstrated that an early cellular change induced by WRN depletion is a posttranscriptional decrease in the levels of enzymes involved in metabolic pathways that control macromolecular synthesis and protect from oxidative stress. This metabolic shift is tolerated by normal cells but causes mitochondria dysfunction and acute oxidative stress in rapidly growing cancer cells, thereby suppressing their proliferation.ResultsTo identify the mechanism underlying this metabolic shift, we examined global protein synthesis and mRNA nucleocytoplasmic distribution after WRN knockdown. We determined that WRN depletion in HeLa cells attenuates global protein synthesis without affecting the level of key components of the mRNA export machinery. We further observed that WRN depletion affects the nuclear export of mRNAs and demonstrated that WRN interacts with mRNA and the Nuclear RNA Export Factor 1 (NXF1).ConclusionsOur findings suggest that WRN influences the export of mRNAs from the nucleus through its interaction with the NXF1 export receptor thereby affecting cellular proteostasis. In summary, we identified a new partner and a novel function of WRN, which is especially important for the proliferation of cancer cells.

Stanniocalcin 1 Inhibits the Inflammatory Response in Microglia and Protects Against Sepsis-Associated Encephalopathy.

Sepsis-associated encephalopathy is a serious consequence of sepsis, triggered by the host response against an infectious agent, that can lead to brain damage and cognitive impairment. Several mechanisms have been proposed in this bidirectional communication between the immune system and the brain after sepsis as neuroinflammation, oxidative stress, and mitochondrial dysfunction. Stanniocalcin-1 (STC-1), an endogen neuroprotective protein, acts as an anti-inflammatory and suppresses superoxide generation through induction of uncoupling proteins (UCPs) in the mitochondria. Here, we demonstrated a protective role of STC-1 on inflammatory responses in vitro, in activated microglia stimulated with LPS, and on neuroinflammation, oxidative stress, and mitochondrial function in the hippocampus of rats subjected to an animal model of sepsis by cecal ligation and puncture (CLP), as well the consequences on long-term memory. Recombinant human STC-1 (rhSTC1) suppressed the pro-inflammatory cytokine production in LPS-stimulated microglia without changing the UCP-2 expression. Besides, rhSTC1 injected into the cisterna magna decreased acute hippocampal inflammation and oxidative stress and increased the activity of complex I and II activity of mitochondrial respiratory chain and creatine kinase at 24h after sepsis. rhSTC1 was effective in preventing long-term cognitive impairment after CLP. In conclusion, rhSTC1 confers significant neuroprotection by inhibiting the inflammatory response in microglia and protecting against sepsis-associated encephalopathy in rats.

Effective, low cytotoxic cell membranes protector based on amphiphilic conjugate of cellulose sulfate with isobornylphenol

Attaching alkylphenols to hydrophilic macromolecular matrices is an effective means to improve quality of the existing antioxidants and to create new antioxidants. In this work cellulose sulfates in the form of tetrabutylammonium salts was used as a basis for the synthesis of ether containing covalently bonded fragments of 2,6-diisobornyl-4-methylphenol in homogenous medium. Optimum conditions for the synthesis of amphiphilic macromolecules containing up to 6 mass% of hydrophobic terpenophenolic fragments were founded. Polymer structure was proved by the element analysis, UV, IR and NMR spectroscopy. Dynamic light scattering method was used to demonstrate the way the supramolecular assemblies are formed in the solutions of synthesized amphiphilic conjugate. Synthesized conjugates of cellulose sulfate with varying alkylphenols content are characterized by low cytotoxicity, as well as high antioxidant and membrane-protective activity in the biological model, increasing the survival rate of cells under acute oxidative stress. Amphiphilic conjugate in form of tetrabutylammonium salts of cellulose sulfate at low concentration turned out to be more effective than the conjugates of terpenophenols with sodium salts of cellulose sulfate.

Myostatin and muscle atrophy during chronic kidney disease.

Chronic kidney disease (CKD) patients often exhibit a low muscle mass and strength, leading to physical impairment and an increased mortality. Two major signalling pathways control protein synthesis, the insulin-like growth factor-1/Akt (IGF-1/Akt) pathway, acting as a positive regulator, and the myostatin (Mstn) pathway, acting as a negative regulator. Mstn, also known as the growth development factor-8 (GDF-8), is a member of the transforming growth factor-β superfamily, which is secreted by mature muscle cells. Mstn inhibits satellite muscle cell proliferation and differentiation and induces a proteolytic phenotype of muscle cells by activating the ubiquitin-proteasome system. Recent advances have been made in the comprehension of the Mstn pathway disturbance and its role in muscle wasting during CKD. Most studies report higher Mstn concentrations in CKD and dialysis patients than in healthy subjects. Several factors increase Mstn production in uraemic conditions: low physical activity, chronic or acute inflammation and oxidative stress, uraemic toxins, angiotensin II, metabolic acidosis and glucocorticoids. Mstn seems to be only scarcely removed during haemodialysis or peritoneal dialysis, maybe because of its large molecule size in plasma where it is linked to its prodomain. In dialysis patients, Mstn has been proposed as a biomarker of muscle mass, muscle strength or physical performances, but more studies are needed in this field. This review outlines the interconnection between Mstn activation, muscle dysfunction and CKD. We discuss mechanisms of action and efficacy of pharmacological Mstn pathway inhibition that represents a promising treatment approach of striated muscle dysfunction. Many approaches and molecules are in development but until now, no study has proved a benefit in CKD.

Ecotoxicity assessment of a molybdenum mining effluent using acute lethal, oxidative stress, and osmoregulatory endpoints in zebrafish (Danio rerio).

The present study investigated the ecotoxicity of raw mining effluent from the largest molybdenum (Mo) open-pit mine in the Qinling mountains, China, and the treated effluent with neutralization and coagulation/adsorption processes, using zebrafish (Danio rerio). The results showed the following: (1) the mining effluent is acid mine drainage (AMD) and is highly toxic to zebrafish with a 96-h median lethal concentration (LC50) of 3.80% (volume percentage) of the raw effluent; (2) sublethal concentrations of the raw effluent (1/50, 1/10, and 1/2 96-h LC50) induced oxidative stress and osmoregulatory impairment, as reflected by the alterations in activities of superoxide dismutase and catalase and contents of malondialdehyde, and inhibition of Na+, K+-ATPase activity in gills and muscle after 28days of sub-chronic exposure when compared with the unexposed group; and (3) the treatment of the raw effluent with neutralizer (NaOH) and adsorbent activated carbon reduced the acute lethal effect of raw effluent. The used endpoints including acute lethal and biochemical parameters related to oxidative stress and osmoregulatory impairment in zebrafish are cost-effective for toxicity assessment of AMD like the studied Mo mining effluent. Mining effluent management strategies extended by these results, i.e., the restriction of discharging raw and diluted effluent to adjacent waterways and the introduction of bio-monitoring system across all mining drainages in this area, were also proposed and discussed.

Acute Inflammation and Oxidative Stress Induced by Lipopolysaccharide and the Ameliorative Effect of Stingless Bee Honey.

Systemic acute inflammation is the hallmark of sepsis and is associated with multiple organ dysfunction. This study investigated the potential of Stingless Bee Honey (SBH) to suppress lipopolysaccharide (LPS)-induced systemic acute inflammation in rats and to reveal the probable mechanism of action. Rats received 4.6 and 9.2 g/kg SBH for 7 days followed by a single injection of LPS after which blood samples were taken 6h later. LPS induced liver, kidney, heart, and lung injury, were manifested by increased serum transaminases, alkaline phosphatase, creatine kinase, creatinine, and urea, along with multiple histological alterations, particularly leukocyte infiltration. Pro-inflammatory cytokines were elevated in the serum, and NF-κB p65, p38 MAPK, and HMGB-1 were significantly increased in different tissues of LPS-challenged rats. SBH prevented tissue injury, ameliorated pro-inflammatory cytokines, and suppressed NF-κB p65, p38 MAPK, and HMGB-1 in rats that had received LPS. In addition, SBH diminished reactive oxygen species (ROS) production, lipid peroxidation, and oxidative DNA damage, and enhanced glutathione and Nrf2 in LPS-treated rats. SBH prevents systemic acute inflammation by suppressing NF-κB, p38 MAPK, HMGB-1, oxidative stress, and tissue injury in rats. Thus, SBH may represent an effective anti-inflammatory nutraceutical, pending further mechanistic studies.

Abstract P046: Variable Effect Of Gstm1 Knockout In Mice

Glutathione S-transferase μ-1 (GSTM1) is an enzyme that has a role in the detoxification of electrophiles, including xenobiotics and products of oxidative stress. In humans, the GSTM1(0) null allele deletion variant is highly prevalent and is associated with both an increase in oxidative stress and an increased risk/severity of a variety of diseases, including cancers, chronic kidney disease, hypertension, and coronary artery disease.Recently, we generated a Gstm1 knockout ( Gstm1 -/- ) mouse line on a 129S6 background. Using these animals, we demonstrated that the loss of GSTM1 resulted in increased oxidative stress and greater kidney injury with either subtotal nephrectomy-induced chronic kidney disease or angiotensin II-induced hypertension, in accordance with clinical data.Following myocardial infarction, reperfusion of the heart results in additional tissue damage that is also mediated by acute oxidative stress. Here, we used an ex vivo Langendorff-perfused heart model of acute cardiac ischemia-reperfusion injury (IRI). Contrary to the expectation that hearts from Gstm1 -/- mice would be more susceptible to IRI, we found that the loss of the antioxidant enzyme GSTM1 was protective in males compared to age-matched wild-type controls. In contrast, the Gstm1 -/- genotype was deleterious in female hearts as expected.To explore the hypothesis that the loss of GSTM1 causes compensatory upregulation of other GSTs and that this effect varies based on both tissue and sex, we examined mRNA expression of α, θ, κ, μ, and π classes of Gst genes via qPCR and corresponding protein expression via HPLC and western blot. We found significant differences between male vs. female and heart vs. kidney in several GSTs both in their expression in wild-type mice and in the change in expression between wild-type and Gstm1 -/- mice. These results suggest that the severity of cardiac IRI may depend on the adaptive response mediated by genes encoding GST enzymes.

Acute brain inflammation, white matter oxidative stress, and myelin deficiency in a model of neonatal intraventricular hemorrhage.

Neonatal intraventricular hemorrhage (IVH) leads to posthemorrhagic hydrocephalus (PHH), brain injury, and long-term disability. Current therapy for IVH is based on treating PHH but does not address the underlying brain injury. In order to develop pharmacological treatment for IVH, there must be a better understanding of the underlying pathology of this disease. This study was designed to determine the time course of the acute inflammation and oxidative stress that may underlie the progressive pathology of IVH. The authors sought to understand the temporal relationships among inflammation, oxidative stress, and white matter pathology in a rat model of IVH. A rat model of IVH consisting of hemoglobin injection into the lateral ventricle was used. Tissue was analyzed via biochemical and histological methods to map the spatiotemporal distribution of innate immune activation and oxidative stress. White matter was quantified using both immunohistochemistry and Western blot for myelin basic protein (MBP) in the corpus callosum. IVH led to acute induction of inflammatory cytokines, followed by oxidative stress. Oxidative stress was concentrated in white matter, adjacent to the lateral ventricles. Animals with IVH initially gained weight at a lower rate than control animals and had larger ventricles and less MBP than control animals. Experimental IVH induces global inflammation throughout the brain and oxidative stress concentrated in the white matter. Both of these phenomena occur early after IVH. This has implications for human neonates with immature white matter that is exquisitely sensitive to inflammation and oxidative stress. Antiinflammatory or antioxidant therapy for IVH may need to be initiated early in order to protect developing white matter.

\u03b2-Lapachone Induces Acute Oxidative Stress in Rat Primary Astrocyte Cultures that is Terminated by the NQO1-Inhibitor Dicoumarol

β-lapachone (β-lap) is reduced in tumor cells by the enzyme NAD(P)H: quinone acceptor oxidoreductase 1 (NQO1) to a labile hydroquinone which spontaneously reoxidises to β-lap, thereby generating reactive oxygen species (ROS) and oxidative stress. To test for the consequences of an acute exposure of brain cells to β-lap, cultured primary rat astrocytes were incubated with β-lap for up to 4 h. The presence of β-lap in concentrations of up to 10 µM had no detectable adverse consequences, while higher concentrations of β-lap compromised the cell viability and the metabolism of astrocytes in a concentration- and time-dependent manner with half-maximal effects observed for around 15 µM β-lap after a 4 h incubation. Exposure of astrocytes to β-lap caused already within 5 min a severe increase in the cellular production of ROS as well as a rapid oxidation of glutathione (GSH) to glutathione disulfide (GSSG). The transient cellular accumulation of GSSG was followed by GSSG export. The β-lap-induced ROS production and GSSG accumulation were completely prevented in the presence of the NQO1 inhibitor dicoumarol. In addition, application of dicoumarol to β-lap-exposed astrocytes caused rapid regeneration of the normal high cellular GSH to GSSG ratio. These results demonstrate that application of β-lap to cultured astrocytes causes acute oxidative stress that depends on the activity of NQO1. The sequential application of β-lap and dicoumarol to rapidly induce and terminate oxidative stress, respectively, is a suitable experimental paradigm to study consequences of a defined period of acute oxidative stress in NQO1-expressing cells.

The Effect of Prickly Pear, Pumpkin, and Linseed Oils on Biological Mediators of Acute Inflammation and Oxidative Stress Markers.

Medicinal plants have been used as a source of effective and safe alternative therapeutic agents for various ailments including inflammation. In fact, the aim of this study is to assess the topical anti-inflammatory and antioxidative potential effects of Cucurbita pepo (pumpkin), Linum usitatissimum (linseed), and Opuntia ficus indica (prickly pear) oils on acute inflammation using carrageenan-induced paw edema model. The study was conducted on 36 rats splitted in 6 groups: a normal control group and 5 carrageenan-treated groups (1%), each treated with either a normal saline, the reference drug (“Inflocine®” 2 mg/paw), pumpkin, linseed, or prickly pear oils (25 μl/paw). The response to these treatments was mainly assessed by the measuring of edema paw size, hematological and biochemical analysis, oxidative stress testing, and histological study. All the studied seed oils especially prickly pear oil proved to be efficient in treating acute inflammation. The oil-treated groups revealed a significant (p < 0.05) decrease in the clinical signs of inflammation, hematological parameters (white blood cells and platelets), concentrations of CRP and fibrinogen, and congestion compared to the normal saline-treated group. The results also showed that the tested oils, endowed with a radical scavenging ability, could significantly increase the activities of SOD, CAT, and GPx in carrageenan-treated skin by reducing the lipid peroxidation and protein oxidation (TBARS, AOPP). The anti-inflammatory effect of the tested oils was closely related to both their antioxidant properties as well as their bioactive compounds (polyunsaturated fatty acids, vitamin E, and phytosterols). For the first time, the findings of the current study highlight the “in vivo” anti-inflammatory property of pumpkin, linseed, and prickly pear oils on carrageenan-induced acute inflammation by regulating inflammatory mediators and oxidative stress markers.

Reduction of Protein Bound Methionine Sulfoxide by a Periplasmic Dimethyl Sulfoxide Reductase.

In proteins, methionine (Met) can be oxidized into Met sulfoxide (MetO). The ubiquitous methionine sulfoxide reductases (Msr) A and B are thiol-oxidoreductases reducing MetO. Reversible Met oxidation has a wide range of consequences, from protection against oxidative stress to fine-tuned regulation of protein functions. Bacteria distinguish themselves by the production of molybdenum-containing enzymes reducing MetO, such as the periplasmic MsrP which protects proteins during acute oxidative stress. The versatile dimethyl sulfoxide (DMSO) reductases were shown to reduce the free amino acid MetO, but their ability to reduce MetO within proteins was never evaluated. Here, using model oxidized proteins and peptides, enzymatic and mass spectrometry approaches, we showed that the Rhodobacter sphaeroides periplasmic DorA-type DMSO reductase reduces protein bound MetO as efficiently as the free amino acid L-MetO and with catalytic values in the range of those described for the canonical Msrs. The identification of this fourth type of enzyme able to reduce MetO in proteins, conserved across proteobacteria and actinobacteria, suggests that organisms employ enzymatic systems yet undiscovered to regulate protein oxidation states.

Phosphorylation within the bipartite NLS alters the localization and toxicity of the ER stress response factor DDIT3/CHOP

Regulated nuclear-cytoplasmic trafficking is a well-established mechanism utilized by cells to regulate adaptive and maladaptive responses to acute oxidant stress. Commonly associated with endoplasmic reticulum stress, the bZIP transcription factor CCAAT/enhancer-binding protein homologous protein (CHOP/DDIT3) mediates the cellular response to redox stress with effects on cellular growth, differentiation, and survival. We show through functional analyses that CHOP contains a conserved, compound pat4/bipartite nuclear localization signal within the basic DNA-binding domain. Using phylogenetic analyses and mass spectrometry, we now show that Ser107 located within the linker region of the bipartite NLS domain is a substrate for phosphorylation under standard culture conditions. Studies using the S107E phospho-mimic of CHOP indicate that changes in the charge properties at this residue regulate CHOP's nuclear-to-cytoplasmic ratio. And while co-stimulation with the SERCA inhibitor thapsigargin induced injury in cells expressing wild-type CHOP, the S107A point-mutant blocked this response. These findings indicate that phosphorylation within the bipartite NLS exerts regulatory effects on both the subcellular localization and toxic potential of DDIT3/CHOP. Future studies geared towards defining the relevant kinase/phosphatase networks that converge on the phosphorylation-regulated NLS (prNLS) phosphoepitope may provide an opportunity to constrain cellular damage in the context of acute ER stress.

Emerging contaminant 1,3,6,8-tetrabromocarbazole induces oxidative damage and apoptosis during the embryonic development of zebrafish (Danio rerio)

Since polyhalogenated carbazoles (PHCs) have been widely detected at high concentrations in multiple environmental media in recent years, the health risk of exposure to these compounds has drawn increasing attention. Most studies have mainly focused on their dioxin-like toxicity, which is induced through the AhR pathway, because PHCs have structures similar to those of polychlorinated dibenzofurans (PCDFs). In addition, most xenobiotic compounds induce oxidative stress in organisms, which is a more common mechanism of toxicity induction. However, there is limited information regarding the oxidative stress and damage induced by PHCs in vivo. The PHC 1,3,6,8-tetrabromocarbazole (1368-TBCZ) is detected at high concentration and frequency. In the present study, the toxic effects (acute toxicity, developmental toxicity, oxidative stress, and apoptosis) induced by 1368-TBCZ at three different concentrations were investigated using zebrafish embryos. It was concluded that the 96 h median lethal concentration (LC50) of 1368-TBCZ for zebrafish embryos was greater than 2.0 mg L−1. The results showed that 1368-TBCZ had little effect on the hatching rate of zebrafish embryos. However, 1368-TBCZ at 0.5 and 2.0 mg L−1 inhibited skeletal and cardiac development. It promoted ROS production, CAT enzyme activity, lipid peroxidation, DNA damage, and apoptosis, even at the lowest dose (0.1 mg L−1). In addition, 1368-TBCZ influenced oxidative stress-related gene expression, upregulating the expression of caspase 3 and p53 at 2.0 mg L−1 and inhibiting the expression of caspase 9, FoxO3b, and Bcl-2/Bax. The present study comprehensively evaluated 1368-TBCZ-induced toxicity in zebrafish, providing valuable data for better evaluation of the potential risks posed by this PHC.