Oxidative Modification Of Proteins Research Articles

Extracellularly secreted cysteine derived from cystine regulates oxidative and electrophilic stress in HepG2 cells

While cysteine (CysSH) is known to be exported into the extracellular space, its biological significance is not well understood. The present study examined the movement of extracellular CysSH using stable isotope-labeled cystine (CysSSCys), which is transported into cells and reduced to CysSH. Exposure of HepG2 cells to 100 µM stable isotope-labeled CysSSCys resulted in 70 µM labeled CysSH in cell medium 1 h after CysSSCys exposure. When the cell medium was collected and incubated with either hydrogen peroxide (H2O2) or atmospheric electrophiles, such as 1,2-naphthoquinone, 1,4-naphthoquinone and 1,4-benzoquinone, CysSH in the cell medium was almost completely consumed. In contrast, extracellular levels of CysSH were unaltered during exposure of HepG2 cells to H2O2 for up to 2 h, suggesting redox cycling of CysSSCys/CysSH in the cell system. Experiments with and without changing cell medium containing CysSH from HepG2 cells revealed that oxidative and electrophilic modifications of cellular proteins, caused by exposure to H2O2 and 1,2-naphthoquinone, were significantly repressed by CysSH in the medium. We also examined participation of enzymes and/or antioxidants in intracellular reduction of CysSSCys to CysSH. These results provide new findings that extracellular CysSH derived from CysSSCys plays a role in the regulation of oxidative and electrophilic stress.

The association of protein-bound methionine sulfoxide with proteomic basis for aging in beech seeds

BackgroundEuropean beech (Fagus sylvatica L.) trees produce seeds irregularly; therefore, it is necessary to store beech seeds for forestation. Despite the acquisition of desiccation tolerance during development, beech seeds are classified as intermediate because they lose viability during long-term storage faster than typical orthodox seeds. In this study, beech seeds stored for short (3 years) or long (20 years) periods under optimal conditions and displaying 92 and 30% germination capacity, respectively, were compared.ResultsAged seeds displayed increased membrane damage, manifested as electrolyte leakage and lipid peroxidation levels. Analyses have been based on embryonic axes, which contained higher levels of reactive oxygen species (ROS) and higher levels of protein-bound methionine sulfoxide (MetO) in aged seeds. Using label-free quantitative proteomics, 3,949 proteins were identified, of which 2,442 were reliably quantified pointing to 24 more abundant proteins and 35 less abundant proteins in beech seeds under long-term storage conditions. Functional analyses based on gene ontology annotations revealed that nucleic acid binding activity (molecular function), ribosome organization or biogenesis and transmembrane transport (cellular processes), translational proteins (protein class) and membranous anatomical entities (cellular compartment) were affected in aged seeds. To verify whether MetO, the oxidative posttranslational modification of proteins that can be reversed via the action of methionine sulfoxide reductase (Msr) enzymes, is involved in the aging of beech seeds, we identified and quantified 226 MetO-containing proteins, among which 9 and 19 exhibited significantly up- and downregulated MetO levels, respectively, in beech seeds under long-term storage conditions. Several Msr isoforms were identified and recognized as MsrA1-like, MsrA4, MsrB5 and MsrB5-like in beech seeds. Only MsrA1-like displayed decreased abundance in aged seeds.ConclusionsWe demonstrated that the loss of membrane integrity reflected in the elevated abundance of membrane proteins had a higher impact on seed aging progress than the MetO/Msr system. Proteome analyses enabled us to propose protein Sec61 and glyceraldehyde-3-phosphate dehydrogenase as potential longevity modulators in beech seeds.

SYNTHESIS OF NEW BODIPY HYDRAZIDE FLUORESCENT PROBES FOR THE DETECTION OF CARBONYLATED PROTEINS GENERATED BY OXIDATIVE STRESS.

Oxidative stress is a cellular disorder implicated in various severe diseases and redox biology and represents an important field of research for the last decades. One of the major consequences of oxidative stress is the carbonylation of proteins, which is also a reliable marker to assess protein oxidative modifications. Accumulation of carbonylated proteins has been associated with aging and age-related diseases and can ultimately causes cell death. Detection of these oxidative modifications is essential to understand and discover new treatments against oxidative stress. We describe the design and the synthetic pathway of new BODIPY fluorescent probes functionalized with hydrazide function for protein carbonyl labeling to improve existing methodologies such as 2D-Oxi electrophoresis. Hydrazide BODIPY analogues show very good fluorescent properties such as NIR emission up to 633 nm and quantum yield up to 0.88. These new probes were validated for the detection and quantification of carbonylated proteins with 2D-Oxi electrophoresis using mouse muscle protein extracts, as well as both flow cytometry and microscopy using oxidant stressed C2C12 cells.

Valproic Acid Causes Redox-Regulated Post-Translational Protein Modifications That Are Dependent upon P19 Cellular Differentiation States

Valproic acid (VPA) is a common anti-epileptic drug and known neurodevelopmental toxicant. Although the exact mechanism of VPA toxicity remains unknown, recent findings show that VPA disrupts redox signaling in undifferentiated cells but has little effect on fully differentiated neurons. Redox imbalances often alter oxidative post-translational protein modifications and could affect embryogenesis if developmentally critical proteins are targeted. We hypothesize that VPA causes redox-sensitive post-translational protein modifications that are dependent upon cellular differentiation states. Undifferentiated P19 cells and P19-derived neurons were treated with VPA alone or pretreated with D3T, an inducer of the nuclear factor erythroid 2-related factor 2 (NRF2) antioxidant pathway, prior to VPA exposure. Undifferentiated cells treated with VPA alone exhibited an oxidized glutathione redox couple and increased overall protein oxidation, whereas differentiated neurons were protected from protein oxidation via increased S-glutathionylation. Pretreatment with D3T prevented the effects of VPA exposure in undifferentiated cells. Taken together, our findings support redox-sensitive post-translational protein alterations in undifferentiated cells as a mechanism of VPA-induced developmental toxicity and propose NRF2 activation as a means to preserve proper neurogenesis.

The Intensity of Lipid Peroxide Oxidation Processes and the System State of Antioxidant Protection of Broiler Chicken Due to the Action of the Synbiotic Preparation in Complex with the Disinfectant

Developing methods for increasing the immune reactivity and antioxidant potential of the bird's body during critical periods of growth is an urgent task today. The purpose of the research was to find out the influence of the synbiotic "Biomagn" in combination with the disinfectant "Diolide" on the intensity of the processes of peroxide oxidation of lipids and the activity of the system of antioxidant protection in the organism of chickens. The research was carried out on 2 groups of chickens, 100 in each, starting from 1 to 41 days of age: the control group was fed with standard compound feed (SCF); the chickens of the experimental group were fed with SCF, and the synbiotic preparation "Biomagn" based on 0.5 kg per ton of compound feed. The experimental group received a solution of the preparation "Diolide" with water. For conducting immunological research, blood was taken from chickens at different age periods: from 10-, 27-, 31-, and 41-day-old chickens. The use of the synbiotic preparation "Biomagn" in combination with the disinfectant "Diolide" in the chickens of the experimental group normalized the intensity of the processes of lipid peroxidation and oxidative modification of proteins in the poultry's organism - a decrease was established (p <0.05–0.001) in GPO content and TBK-active products and aldehyde derivatives oxidative modification of proteins in the blood compared to the control. The detected event was determined by increased activity of the enzyme link of the antioxidant protection system of the organism of chickens.

AOP report: Development of an adverse outcome pathway for deposition of energy leading to cataracts.

Cataracts are one of the leading causes of blindness, with an estimated 95 million people affected worldwide. A hallmark of cataract development is lens opacification, typically associated not only with aging but also radiation exposure as encountered by interventional radiologists and astronauts during the long-term space mission. To better understand radiation-induced cataracts, the adverse outcome pathway (AOP) framework was used to structure and evaluate knowledge across biological levels of organization (e.g., macromolecular, cell, tissue, organ, organism and population). AOPs identify a sequence of key events (KEs) causally connected by key event relationships (KERs) beginning with a molecular initiating event to an adverse outcome (AO) of relevance to regulatory decision-making. To construct the cataract AO and retrieve evidence to support it, a scoping review methodology was used to filter, screen, and review studies based on the modified Bradford Hill criteria. Eight KEs were identified that were moderately supported by empirical evidence (e.g., dose-, time-, incidence-concordance) across the adjacent (directly linked) relationships using well-established endpoints. Over half of the evidence to justify the KER linkages was derived from the evidence stream of biological plausibility. Early KEs of oxidative stress and protein modifications had strong linkages to downstream KEs and could be the focus of countermeasure development. Several identified knowledge gaps and inconsistencies related to the quantitative understanding of KERs which could be the basis of future research, most notably directed to experiments in the range of low or moderate doses and dose-rates, relevant to radiation workers and other occupational exposures.

Effects of Glyprolins on Lipid and Protein Peroxidation in the Hypothalamic Region in Experimental Hyperthyroidism

We investigate effects of glyproline-type neuropeptides on lipid and protein peroxidation in the hypothalamic brain region of rats under the conditions of experimental hyperthyroidism. The state of hyperthyroidism in animals was simulated by intragastric administration of sodium pentahydrate of L-thyroxine at a dose of 150 µg/kg for 21 days. The following experimental groups (n=10) were formed: 1) control group — intact animals (control); 2) animals treated with L-thyroxine sodium salt pentahydrate (hyperthyroidism); 3) animals treated with Thr-Lys-Pro-Arg-Pro-Gly-Pro (celank); 4) animals treated with Pro-GlyPro (doses of 87 and 33 µg/kg/day, respectively) intraperitoneally daily during 21 days starting one day after the last administration of sodium pentahydrate of L-thyroxine. The level of lipid peroxidation processes was assessed by the initial level of TBA-reactive products, spontaneous and ascorbate-dependent lipid peroxidation rates in hypothalamic tissue homogenate. Protein peroxidation products were determined by the reaction between oxidized amino acid residues of proteins and 2,4-dinitrophenylhydrazone. The enzymatic part of the antioxidant system of hypothalamic region was estimated by measuring the activity of superoxide dismutase and catalase. In the setting of Thr-Lys-Pro-Arg-Pro-Gly-Pro and Pro-Gly-Pro administration under experimental hyperthyroidism, the intensity of lipid and protein peroxidation processes was decreased, while the activity of antioxidant enzymes-superoxide dismutase and catalase was restored in the hypothalamic tissue. The experimental data obtained indicate that, under the conditions of experimental hyperthyroidism, Thr-Lys-Pro-Arg-Pro-Gly-Pro and Pro-Gly-Pro compounds exhibit an antioxidant and antiradical activity with respect to parameters of lipoperoxidation and oxidative modification of proteins, as well as with respect to enzymatic defense systems in the hypothalamic brain region of laboratory animals.

The influence of newly synthesized tellurium-containing cyanine dyes on the intensity of oxidative processes in the bodies of mammals

The purpose of this work was to study the influence of new synthesized organotellurium compounds (TOCs) on the intensity of oxidative processes in the body of mammals – in this case, the blood and liver of rats.The experiments were performed on white outbred rats, which were given a single dose of various TOC derivatives (0.01 g/kg). The next day, the animals were decapitated, blood was collected and the liver was isolated. The content of products of oxidative modification of lipids and proteins, as well as the low molecular weight antioxidant glutathione, was determined in blood plasma, erythrocytes and liver homogenate.It was found that all TOC derivatives studied significantly increase the intensity of lipid peroxidation in erythrocytes and hepatocytes, as evidenced by a multiple increase in the concentration of malondialdehyde (MDA) in them. At the same time, TOC suppresses the levels of oxidative damage to liver proteins, which is expressed in a significant decrease in the content of carbonyl groups. A study of glutathione content in the rat erythrocytes showed the absence of any significant effects of TOS on this antioxidant in erythrocytes.However, changes in its concentration were found in the liver, which depend on the nature of TOS (for TOS1 and TOS3 a decrease and for TOS2 a slight increase). Newly synthesized TOC demonstrate pronounced prooxidant properties, significantly increasing the intensity of oxidative processes in lipids, which makes them promising agents for antibacterial, antiviral and antitumor therapy.

Progress in Understanding Oxidative Stress, Aging, and Aging-Related Diseases.

Under normal physiological conditions, reactive oxygen species (ROS) are produced through redox reactions as byproducts of respiratory and metabolic activities. However, due to various endogenous and exogenous factors, the body may produce excessive ROS, which leads to oxidative stress (OS). Numerous studies have shown that OS causes a variety of pathological changes in cells, including mitochondrial dysfunction, DNA damage, telomere shortening, lipid peroxidation, and protein oxidative modification, all of which can trigger apoptosis and senescence. OS also induces a variety of aging-related diseases, such as retinal disease, neurodegenerative disease, osteoarthritis, cardiovascular diseases, cancer, ovarian disease, and prostate disease. In this review, we aim to introduce the multiple internal and external triggers that mediate ROS levels in rodents and humans as well as the relationship between OS, aging, and aging-related diseases. Finally, we present a statistical analysis of effective antioxidant measures currently being developed and applied in the field of aging research.

Hypochlorous acid derived from microglial myeloperoxidase could mediate high-mobility group box 1 release from neurons to amplify brain damage in cerebral ischemia–reperfusion injury

Myeloperoxidase (MPO) plays critical role in the pathology of cerebral ischemia–reperfusion (I/R) injury via producing hypochlorous acid (HOCl) and inducing oxidative modification of proteins. High-mobility group box 1 (HMGB1) oxidation, particularly disulfide HMGB1 formation, facilitates the secretion and release of HMGB1 and activates neuroinflammation, aggravating cerebral I/R injury. However, the cellular sources of MPO/HOCl in ischemic brain injury are unclear yet. Whether HOCl could promote HMGB1 secretion and release remains unknown. In the present study, we investigated the roles of microglia-derived MPO/HOCl in mediating HMGB1 translocation and secretion, and aggravating the brain damage and blood-brain barrier (BBB) disruption in cerebral I/R injury. In vitro, under the co-culture conditions with microglia BV cells but not the single culture conditions, oxygen–glucose deprivation/reoxygenation (OGD/R) significantly increased MPO/HOCl expression in PC12 cells. After the cells were exposed to OGD/R, MPO-containing exosomes derived from BV2 cells were released and transferred to PC12 cells, increasing MPO/HOCl in the PC12 cells. The HOCl promoted disulfide HMGB1 translocation and secretion and aggravated OGD/R-induced apoptosis. In vivo, SD rats were subjected to 2 h of middle cerebral artery occlusion (MCAO) plus different periods of reperfusion. Increased MPO/HOCl production was observed at the reperfusion stage, accomplished with enlarged infarct volume, aggravated BBB disruption and neurological dysfunctions. Treatment of MPO inhibitor 4-aminobenzoic acid hydrazide (4-ABAH) and HOCl scavenger taurine reversed those changes. HOCl was colocalized with cytoplasm transferred HMGB1, which was blocked by taurine in rat I/R-injured brain. We finally performed a clinical investigation and found that plasma HOCl concentration was positively correlated with infarct volume and neurological deficit scores in ischemic stroke patients. Taken together, we conclude that ischemia/hypoxia could activate microglia to release MPO-containing exosomes that transfer MPO to adjacent cells for HOCl production; Subsequently, the production of HOCl could mediate the translocation and secretion of disulfide HMGB1 that aggravates cerebral I/R injury. Furthermore, plasma HOCl level could be a novel biomarker for indexing brain damage in ischemic stroke patients.

Environmental factors influence cross-talk between a heat shock protein and an oxidative stress protein modification in the lizard Gallotia galloti.

Better understanding how organisms respond to their abiotic environment, especially at the biochemical level, is critical in predicting population trajectories under climate change. In this study, we measured constitutive stress biomarkers and protein post-translational modifications associated with oxidative stress in Gallotia galloti, an insular lizard species inhabiting highly heterogeneous environments on Tenerife. Tenerife is a small volcanic island in a relatively isolated archipelago off the West coast of Africa. We found that expression of GRP94, a molecular chaperone protein, and levels of protein carbonylation, a marker of cellular stress, change across different environments, depending on solar radiation-related variables and topology. Here, we report in a wild animal population, cross-talk between the baseline levels of the heat shock protein-like GRP94 and oxidative damage (protein carbonylation), which are influenced by a range of available temperatures, quantified through modelled operative temperature. This suggests a dynamic trade-off between cellular homeostasis and oxidative damage in lizards adapted to this thermally and topologically heterogeneous environment.

The Effects of Oxygen-Derived Free-Radical Scavengers During Normothermic Ex-Situ Heart Perfusion.

Oxidative stress occurs during ex-situ heart perfusion (ESHP) and may negatively affect functional preservation of the heart. We sought to assess the status of key antioxidant enzymes during ESHP, and the effects of augmenting these antioxidants on the attenuation of oxidative stress and improvement of myocardial and endothelial preservation in ESHP. Porcine hearts were perfused for 6 hours with oxygen-derived free-radical scavengers polyethylene glycol (PEG)-catalase or PEG-superoxide dismutase (SOD) or with naive perfusate (control). The oxidative stress-related modifications were determined in the myocardium and coronary vasculature, and contractile function, injury, and endothelial integrity were compared between the groups. The activity of key antioxidant enzymes decreased and adding catalase and SOD restored the enzyme activity. Cardiac function and endothelial integrity were preserved better with restored catalase activity. Catalase and SOD both decreased myocardial injury and catalase reduced ROS production and oxidative modification of proteins in the myocardium and coronary vasculature. The activity of antioxidant enzymes decrease in ESHP. Catalase may improve the preservation of cardiac function and endothelial integrity during ESHP. While catalase and SOD may both exert cardioprotective effects, unbalanced SOD and catalase activity may paradoxically increase the production of reactive species during ESHP.

Changes in Endogenous Intoxication and Antioxidant Defense System Markers in Patients with Tumor-Induced Acute Colonic Obstruction

A comprehensive evaluation of clinical and biochemical markers defining the status of endotoxemia in patients diagnosed with acute colonic obstruction (ACO) was conducted. The findings revealed that advancing stages of ACO corresponded to an increase in serum levels of endogenous intoxication markers and a simultaneous decrease in antioxidant defense system (ADS) markers.
 The aim of the study was to analyze changes in endogenous intoxication and ADS markers in patients with tumor-induced ACO throughout the disease progression and evaluate the outcomes.
 Materials and Methods. The study is based on examining serum levels of endogenous intoxication markers, including middle weight molecules (MWM), products of lipid peroxidation (LPO) - conjugated dienes (CD), malonaldehyde (MA), protein oxidative modification (POM), and key ADS markers, specifically superoxide dismutase (SOD), catalase (CAT), and ceruloplasmin (CP), in 155 patients with ACO throughout the disease progression and 20 apparently healthy individuals.
 Results. Upon patient admission to the hospital, the duration of ACO was found to correlate with an increase in endogenous intoxication markers and a decrease in antioxidant defense markers. Depending on ACO stage, MWM levels were 0.42 (0.38; 0.43) IU, 0.56 (0.51; 0.58) IU, and 0.72 (0.69; 0.73) IU, respectively (р1<0.01, р2<0.01, р3<0.01), with a normal range of 0.23 (0.18; 0.25) IU. In the compensated stage of ACO, MA levels significantly increased compared to the control group, reaching 6.39 (6.25; 6.42) nmol/mL (р1<0.001, р2<0.01, р3<0.05). Additionally, with the progression of the disease, a gradual increase in MA levels up to 6.39 (6.25; 6.42) nmol/mL, 7.88 (7.62; 7.92) nmol/mL, and 8.11 (8.05; 8.15) nmol/mL, respectively, was noted (р1<0.001, р2<0.01, р3<0.05), with a normal range of 3.14 (2.58; 3.17) nmol/mL. Similar trend was observed in serum CD levels - 3.11 (3.02; 3.18) IU, 3.69 (3.52; 3.72) IU, and 4.69 (4.53; 4.82) IU, respectively, with a normal range of 1.41 (1.32; 1.46) IU (р1<0.01, р2<0.01, р3<0.01). The study of LPO intensity via the optical density of aldehyde and ketone derivatives of neutral and basic dinitrophenylhydrazones (POM 356, POM 370, POM 430, POM 530) revealed an increase in POM product levels with the disease progression compared to the control group (р1<0.001, р2<0.01, р3<0.01). The analysis of the ADS showed an opposite trend, characterized by a significant decrease in marker levels. In patients with different ACO stages, serum CAT levels were 8.08 (7.95; 8.12) Н2О2/mL, 6.32 (6.25;6.41) Н2О2/mL, and 5.67 (5.59; 5.75) Н2О2/mL, respectively, with a normal range of 12.36 (12.21; 12.55) Н2О2/ml (р1<0.001, р2<0.01, р3<0.01), while SOD concentration decreased with the disease progression as well - 42.43 (31.75; 51.84) IU, 35.65 (24.72; 45.53) IU, and 32.18 (18.72; 41.15) IU, respectively, with a normal range of 63.60 (54.41; 74.56) IU (р1<0.001, р2<0.01, р3<0.01). In the compensated stage of ACO, CP level exceeded the normal value - 39.21 (38.92; 39.41) IU, with a normal range of 28.9 (28.4; 29.1) IU, indicating a compensatory defensive response of the body to a dramatic increase in LPO products. CP reserves, however, were depleted with the disease progression and a consistent decrease in this marker was subsequently observed: 19.10 (18.91; 19.23) IU in the subcompensated stage and 16.12 (16.01; 16.15) IU in the decompensated stage (р1<0.001, р2<0.01, р3<0.01).
 Conclusions. As a systemic process that induces various metabolic homeostasis disorders, endogenous intoxication serves as the pathogenetic foundation for the development of multiple organ failure in ACO patients. With ACO progression, endogenous intoxication caused an increase in LPO and POM activity, resulting in elevation of highly toxic middle-molecular weight substances, concurrently accompanied by a decline in the AOS activity.

ROS signaling in innate immunity via oxidative protein modifications.

The innate immune response represents the first-line of defense against invading pathogens. Reactive oxygen species (ROS) and reactive nitrogen species (RNS) have been implicated in various aspects of innate immune function, which involves respiratory bursts and inflammasome activation. These reactive species widely distributed within the cellular environment are short-lived intermediates that play a vital role in cellular signaling and proliferation and are likely to depend on their subcellular site of formation. NADPH oxidase complex of phagocytes is known to generate superoxide anion radical (O2 •-) that functions as a precursor for antimicrobial hydrogen peroxide (H2O2) production, and H2O2 is utilized by myeloperoxidase (MPO) to generate hypochlorous acid (HOCl) that mediates pathogen killing. H2O2 modulates the expression of redox-responsive transcriptional factors, namely NF-kB, NRF2, and HIF-1, thereby mediating redox-based epigenetic modification. Survival and function of immune cells are under redox control and depend on intracellular and extracellular levels of ROS/RNS. The current review focuses on redox factors involved in the activation of immune response and the role of ROS in oxidative modification of proteins in macrophage polarization and neutrophil function.

EFFECT OF ACTG(4-7)-PRO-GLY-PRO AND ACTG(6-9)-PRO-GLY-PRO ON THE INTENSITY OF REDOX PROCESSES AND BEHAVIOURAL STATUS OF RATS UNDER THYROID HYPERFUNCTION CONDITIONS

The aim of the work is to study the effect of melanocortins on the intensity of redox processes in the prefrontal region of the brain and the behavioral status of rats against the background of thyroid hyperfunction. Material and methods. In the experiment, the test animals were divided into the following groups (n = 10): intact rats (control); animals treated with sodium salt pentahydrate L-thyroxine (hyperthyroidism); rats receiving ACTH (4-7)-Pro-Gly-Pro and individuals receiving ACTH (6-9)-Pro-Gly-Pro, re-spectively, intraperitoneally daily for 21 days, starting from day 22 of administration of sodium salt pentahydrate L-thyroxine. Hyperthyroidism was simulated in animals by intragastric administration of L-thyroxine sodium salt pentahydrate for 42 days. The intensity of lipoperoxidation processes was studied by the content of diene and triene conjugates in the prefrontal zone tissue, the initial level of TBА-reactive products, and the rates of spon-taneous and ascorbic peroxidation of lipids. The level of protein peroxidation products was determined by the reaction of oxidized amino acid residues of proteins with 2,4-dinitrophenyl hydrazone. Evaluation of the enzymatic unit of the antioxidant system of the prefrontal region was carried out by de-termining the activity of superoxide dismutase and catalase. The behavioral status of laboratory rodents was studied using the «Hole board» test. Results. The use of ACTH(4-7)-Pro-Gly-Pro and ACTH(6-9)-Pro-Gly-Pro compounds under experimental hyperthyroidism led to a decrease in the intensity of the processes of peroxidation of lipids, proteins and the restoration of levels of activity of antioxidant enzymes – superoxide dismutase and catalase in the tissue of the prefrontal region of the brain of animals, as well as correction behavioral indicators in the «Hole board» test. Conclusion. The obtained experimental data indicate that ACTH(4-7)-Pro-Gly-Pro and ACTH(6-9)-Pro-Gly-Pro show antiperoxy and antioxidant activity against lipoperoxidation parameters and oxidative modification of proteins and enzymatic protection systems in the prefrontal brain zone tissue, as well as exert psychocorregating action on behavioral responses of white rats against the background of thyroid hyperfunction.

Free radical processes in the liver mitochondria of rats exposed to diethyl phthalate

Diethyl phthalate (DEF) is a synthetic chemical widely used as plasticizer and additive in personal care and pharmaceutical products. Low-dose exposure to this xenobiotic over a long period contributes to its intake into the human body in a high doses. To date, studies of DEF influence on free radical processes in liver cells, in which it is not only metabolized but can also have a prooxidant effect, remain limited. The aim of our research was to determine ROS formation, the intensity of oxidative modification of proteins (OMP) and proteolytic activity in the mitochondrial fraction of liver tissue of rats exposed to diethyl phtalate. The experimental white outbred rats were divided into three groups: I – intact animals (control), II and III – rats administered DEF orally for three weeks at a doses that reflect the dose levels received by humans, namely 2.5 and 5.4 mg/kg b.w. respectively. The animals were euthanized on the 14th and 21st day after xenobiotic administration. The mitochondrial fraction from the rat liver was isolated and the level of superoxide and hydroxyl radicals, protein carbonyl derivatives, SH-groups and Schiff bases was determined. Proteolytic activity was assessed in the test of hemoglobin cleavage. It was shown that administration of DEF in a dose of 2.5 mg/kg initiated ROS generation and OMP intensification in the rat liver mitochondria only with prolonged administration for 21 days, whereas its administration in a dose of 5.4 mg/kg led to intensification of these processes already on day 14th followed by further amplification on day 21st. The activity of proteolytic enzymes in the mitochondrial fraction was found to be depended on the degree of DEF–induced OMP and was increased with minor OMP intensification but decreased with significant intensification of proteins free radical oxidation. Keywords: carbonyl derivatives, diethyl phthalate, liver, mitochondrial fraction, proteolytic enzymes, ROS, SH-groups

The Protective Impact of Aronia melanocarpa L. Berries Extract against Prooxidative Cadmium Action in the Brain-A Study in an In Vivo Model of Current Environmental Human Exposure to This Harmful Element.

Cadmium (Cd) is a prooxidant that adversely affects human health, including the nervous system. As exposure of the general population to this heavy metal is inevitable, it is crucial to look for agents that can prevent the effects of its toxic action. An experimental model on female rats of current lifetime human exposure to cadmium (3-24-months' treatment with 1 or 5 mg Cd/kg diet) was used to test whether low-level and moderate intoxication can exert a prooxidative impact in the brain and whether supplementation with a 0.1% extract from the berries of Aronia melanocarpa L. (Michx.) Elliott (AE; chokeberry extract) can protect against this action. Numerous parameters of the non-enzymatic and enzymatic antioxidative barrier, as well as total antioxidative and oxidative status (TAS and TOS, respectively), were determined and the index of oxidative stress (OSI) was calculated. Moreover, chosen prooxidants (myeloperoxidase, xanthine oxidase, and hydrogen peroxide) and biomarkers of oxidative modifications of lipids, proteins, and deoxyribonucleic acid were assayed. Cadmium dysregulated the balance between oxidants and antioxidants in the brain and led to oxidative stress and oxidative injury of the cellular macromolecules, whereas the co-administration of AE alleviated these effects. To summarize, long-term, even low-level, cadmium exposure can pose a risk of failure of the nervous system by the induction of oxidative stress in the brain, whereas supplementation with products based on aronia berries seems to be an effective protective strategy.

The role of ubiquitin and heat shock proteins 27 and 70 in the oxidative modification of proteins and the implementation of dexamethasone-induced apoptosis of tumor cells

BACKGROUND: Experimental studies of molecular control of the tumor cell’s redox status, which influences the implementation of apoptosis, are relevant for studying the pathogenesis of tumor growth.
 AIM: Studying the molecular mechanisms of the participation of ubiquitin and heat shock proteins 27 and 70 in the oxidative modification of proteins, amino acids and the implementation of dexamethasone-induced apoptosis of Jurkat tumor cells in conditions of decreased antioxidant protection by blocking the synthesis of reduced glutathione.
 MATERIAL AND METHODS: The effect of the inhibitor of de novo glutathione synthesis buthionine sulfoximine at a final concentration of 1 mM and/or the apoptosis inducer dexamethasone at a final concentration of 10 μM on the content of hydroxyl radical, protein-bound glutathione, carbonyl derivatives of proteins, oxidized tryptophan and bityrosine, ubiquitin, heat shock proteins 27 and 70, number of annexin V-positive cells and caspase-3 activity in Jurkat tumor cells was studied. Using the Shapiro–Wilk test, the normality of the distribution of indicators was assessed. Statistical hypotheses about the differences between the study groups were tested using the nonparametric Mann–Whitney test with a Bonferroni correction; correlation analysis was performed using the Spearman method at a significance level of p 0.05.
 RESULTS: In tumor cells of the Jurkat line, exposure to buthionine sulfoximine and dexamethasone was accompanied by a statistically significant decrease in the content of ubiquitin by 24% (p=0.004), protein-bound glutathione by 93% (p=0.003), oxidized tryptophan by 57% (p=0.003), and heat protein shock 70 by 56% (p=0.004), as well as an increase in the concentration of carbonyl derivatives of proteins by 53% (p=0.004), heat shock protein 27 by 104% (p=0.004), associated with an increase in the number of annexin-positive cells by 1296% (p=0.006) and caspase-3 activity by 258% relative to the values in intact cells. The relationship between an increase in the number of annexin-positive cells and caspase-3 activity with changes in the content of protein-bound glutathione, carbonylated proteins, oxidized tryptophan, ubiquitin and heat shock proteins 27 and 70 in tumor cells with simultaneous exposure to both buthionine sulfoximine and dexamethasone has been proven.
 CONCLUSION: Blocking de novo glutathione synthesis and stimulating apoptosis causes activation of reversible and irreversible oxidative modification of proteins and amino acids against the background of increased oxidative stress in Jurkat tumor cells.

High-Fat Diet-Induced Obesity Increases Brain Mitochondrial Complex I and Lipoxidation-Derived Protein Damage.

Obesity is a risk factor for highly prevalent age-related neurodegenerative diseases, the pathogenesis of whichinvolves mitochondrial dysfunction and protein oxidative damage. Lipoxidation, driven by high levels of peroxidizable unsaturated fatty acids and low antioxidant protection of the brain, stands out as a significant risk factor. To gain information on the relationship between obesity and brain molecular damage, in a porcine model of obesity we evaluated (1) the level of mitochondrial respiratory chain complexes, as the main source of free radical generation, by Western blot; (2) the fatty acid profile by gas chromatography; and (3) the oxidative modification of proteins by mass spectrometry. The results demonstrate a selectively higher amount of the lipoxidation-derived biomarker malondialdehyde-lysine (MDAL) (34% increase) in the frontal cortex, and positive correlations between MDAL and LDL levels and body weight. No changes were observed in brain fatty acid profile by the high-fat diet, and the increased lipid peroxidative modification was associated with increased levels of mitochondrial complex I (NDUFS3 and NDUFA9 subunits) and complex II (flavoprotein). Interestingly, introducing n3 fatty acids and a probiotic in the high-fat diet prevented the observed changes, suggesting that dietary components can modulate protein oxidative modification at the cerebral level and opening new possibilities in neurodegenerative diseases' prevention.

Oxidative Modification, Structural Conformation, and Gel Properties of Pork Paste Protein Mediated by Oxygen Concentration in Modified Atmosphere Packaging

The objective of this study was to investigate the effect of pork oxidation through modified atmosphere packaging (MAP) on gel characteristics of myofibrillar proteins (MP) during the heat-induced gelation process. The pork longissimus thoracis (LT) was treated by MAP at varying oxygen concentrations (0, 20, 40, 60, and 80% O2) with a 5-day storage at 4 °C for the detection of MP oxidation and gel properties. The findings showed the rise of O2 concentration resulted in a significant increase of carbonyl content, disulfide bond, and particle size, and a decrease of sulfhydryl content and MP solubility (p < 0.05). The gel textural properties and water retention ability were significantly improved in MAP treatments of 0–60% O2 (p < 0.05), but deteriorated at 80% O2 level. As the concentration of O2 increased, there was a marked decrease in the α-helix content within the gel, accompanied by a simultaneous increase in β-sheet content (p < 0.05). Additionally, a judicious oxidation treatment (60% O2 in MAP) proved beneficial for crafting dense and uniform gel networks. Our data suggest that the oxidation treatment of pork mediated by O2 concentration in MAP is capable of reinforcing protein hydrophobic interaction and disulfide bond formation, thus contributing to the construction of superior gel structures and properties.