Initiation Of Lipid Peroxidation Research Articles

Antimicrobial activity and mode of action of 1,8-cineol against carbapenemase-producing Klebsiella pneumoniae

Antimicrobial resistance remains one of the most challenging issues that threatens the health of people around the world. Plant-derived natural compounds have received considerable attention for their potential role to mitigate antibiotic resistance. This study was carried out to assess the antimicrobial activity and mode of action of a monoterpene, 1,8-cineol (CN) against carbapenemase-producing Klebsiella pneumoniae (KPC-KP). Results showed that resazurin microplate assay and time-kill analysis revealed bactericidal effects of CN at 28.83 mg/mL. Zeta potential showed that CN increased the surface charge of bacteria and an increase of outer membrane permeability was also detected. CN was able to cause leakage of proteins and nucleic acids in KPC-KP cells upon exposure to CN and ethidium bromide influx/efflux experiment showed the uptake of ethidium bromide into the cell; this was attributed to membrane damage. CN was also found to induce oxidative stress in CN-treated KPC-KP cells through generation of reactive oxygen species which initiated lipid peroxidation and thus damaging the bacterial cell membrane. Scanning and transmission electron microscopies further confirmed the disruption of bacterial cell membrane and loss of intracellular materials. In this study, we demonstrated that CN induced oxidative stress and membrane damage resulting in KPC-KP cell death.

Antioxidant properties of soils and associated vegetation in the polar urals

The increase in global air temperatures and climate aridization, associated with climate change, contribute to the biodegradation of soil organic matter (SOM) which is crucial for the ecosystems in cold and humid environments. SOM of the high-latitude mountain systems might be more vulnerable to temperature growth compared to that of plain landscapes due to higher soil drainage and solar irradiation. Thus, it is important to study the biochemical processes underlying the conservation of biomolecules of organic residues in these environments. Even though antioxidants might in principle contribute to stabilization of SOM, at the moment there is no established theory about the sources of soil antioxidant activity (AOA) and the mechanisms of its realization. In particular, in the relevant literature there is no data on the AOA of cryogenic soils. In this study we assess the antioxidant activity (radical scavenging activity and the ability to inhibit the initiated lipid peroxidation) of soil extracts from mountain tundra and meadows in Polar Ural (Russia) in model biological substrate. We show that SOM from sites with closed vegetation is less susceptible to oxidative degradation due to the high content of amino acids, organic forms of C and N including their water-soluble fractions, and low C/N ratio. On sites with scarce vegetation, soils exhibit low AOA and are vulnerable to the increase in temperature and aeration. Decreased AOA, low productivity of tundra plant communities, and the occurrence of large bare spots (up to 70% of the habitat) make these ecosystems most sensitive to climate change.

Preparation, Antioxidant Properties and Ability to Increase Intracellular NO of a New Pyridoxine Derivative B6NO.

In the case of various pathologies, an imbalance between ROS generation and the endogenous AOS can be observed, which leads to excessive ROS accumulation, intensification of LPO processes, and oxidative stress. For the prevention of diseases associated with oxidative stress, drugs with antioxidant activity can be used. The cytotoxic, antioxidant, and NO-donor properties of the new hybrid compound B6NO (di(3-hydroxy-4,5-bis(hydroxymethyl)-2-methylpyridinium) salt of 2-(nitrooxy)butanedioic acid) were studied. It was determined that B6NO chelates iron ions by 94%, which indicates B6NO’s ability to block the Fenton reaction. The hybrid compound B6NO inhibits the process of initiated lipid peroxidation more effectively than pyridoxine. It was shown that B6NO exhibits antioxidant properties by decreasing ROS concentration in normal cells during the oxidative stress induction by tert-Butyl peroxide. At the same time, the B6NO antioxidant activity on tumor cells was significantly lower. B6NO significantly increases the intracellular nitrogen monoxide accumulation and showed low cytotoxicity for normal cells (IC50 > 4 mM). Thus, the results indicate a high potential of the B6NO as an antioxidant compound.

Incense Smoke Exposure: An Appraisal of Organ Toxicity

Background: This narrative type review aimed to address organ toxicity emanating from incense usage.Methods: An online search using the following MeSH terms “Incense smoke,”, “adverse effects,”“organotoxicity”, “oxidative stress” and “inflammation” was done to identify studies directly applicable toadverse effects of incense smoke exposure.Findings: Exposure to incense smoke demonstrated various toxicity changes in the kidney, testes, lungs,liver and heart. Renal effects included a decrease in oxidative stress markers GSH and CAT, increase inMDA, serum creatinine uric acid and blood urea nitrogen (BUN). Testicular toxicityrevealed significantdisturbances in spermatogenetic patterns, testicular atrophy, germinal aplasia, hypospermia and damage tothe basal seminiferous epithelia tissue. In the cardiac muscle, ultrastructural changes, increased oxidativestress, inflammation, and altered cardiac hypertrophic gene expression was noted. Thenegative impactof incense smoke emanating from free radical (ROS), lipid peroxidation and GSH destabilizes vascularhomeostasis and initiates ahyperinflammatory response, warranting the need to understand the conceptualbasis of the mode of action linked to incense exposure.Conclusion: We highlight that incense generates ROS which initiates lipid peroxidation through ATP energydepletion and reduction in the natural antioxidants. This subsequently triggers oxidative stress, inflammationand endothelial dysfunction resulting in organotoxicity

Osmotic stress and vesiculation as key mechanisms controlling bacterial sensitivity and resistance to TiO2 nanoparticles

Toxicity mechanisms of metal oxide nanoparticles towards bacteria and underlying roles of membrane composition are still debated. Herein, the response of lipopolysaccharide-truncated Escherichia coli K12 mutants to TiO2 nanoparticles (TiO2NPs, exposure in dark) is addressed at the molecular, single cell, and population levels by transcriptomics, fluorescence assays, cell nanomechanics and electrohydrodynamics. We show that outer core-free lipopolysaccharides featuring intact inner core increase cell sensitivity to TiO2NPs. TiO2NPs operate as membrane strippers, which induce osmotic stress, inactivate cell osmoregulation and initiate lipid peroxidation, which ultimately leads to genesis of membrane vesicles. In itself, truncation of lipopolysaccharide inner core triggers membrane permeabilization/depolarization, lipid peroxidation and hypervesiculation. In turn, it favors the regulation of TiO2NP-mediated changes in cell Turgor stress and leads to efficient vesicle-facilitated release of damaged membrane components. Remarkably, vesicles further act as electrostatic baits for TiO2NPs, thereby mitigating TiO2NPs toxicity. Altogether, we highlight antagonistic lipopolysaccharide-dependent bacterial responses to nanoparticles and we show that the destabilized membrane can generate unexpected resistance phenotype.

Vitamin E: necessary nutrient for neural development and cognitive function.

Vitamin E, discovered in 1922, is essential for pregnant rats to carry their babies to term. However, 100 years later, the molecular mechanisms for the vitamin E requirement during embryogenesis remain unknown. Vitamin E's role during pregnancy has been difficult to study and thus, a vitamin E-deficient (E-) zebrafish embryo model was developed. Vitamin E deficiency in zebrafish embryos initiates lipid peroxidation, depletes a specific phospholipid (DHA-phosphatidyl choline), causes secondary deficiencies of choline, betaine and critical thiols (such as glutathione), and dysregulates energy metabolism. Vitamin E deficiency not only distorts the carefully programmed development of the nervous system, but it leads to defects in several developing organs. Both the α-tocopherol transfer protein and vitamin E are necessary for embryonic development, neurogenesis and cognition in this model and likely in human embryos. Elucidation of the control mechanisms for the cellular and metabolic pathways involved in the molecular dysregulation caused by vitamin E deficiency will lead to important insights into abnormal neurogenesis and embryonic malformations.

A 65-Day Fumonisin B Exposure at High Dietary Levels Has Negligible Effects on the Testicular and Spermatological Parameters of Adult Rabbit Bucks.

A 65-day study was undertaken to test the effects of two doses (10 and 20 mg/kg) of dietary fumonisin Bs (FB) on the rabbit male reproduction system. Body and testicular weight was not affected by the intoxication, neither the fatty acid composition of the testicular total phospholipids; the testis histological analysis failed to reveal any toxic effect. The FBs increased the testicular concentration and activity of reduced glutathione and glutathione peroxidase and decreased initial phase lipid peroxidation (conjugated dienes and trienes) in a dose dependent manner. Sperm morphology and chromatin condensation were monitored on Feulgen-stained smears. No significant differences were observed between the treatment groups and between sampling time points. The live cell ratio in the sperm (as assessed with flow cytometry) was not different among groups at any of the five sampling timepoints and was also identical within groups. Similarly, the spermatozoa membrane lipid profile was also identical in all three groups after the total intoxication period. In summary, it was demonstrated that FBs in an unrealistic and unjustified high dose still do not exert any drastic harmful effect on the leporine, male reproduction system, meanwhile slightly augmenting testicular antioxidant response.

Combinatorial Antimicrobial Efficacy and Mechanism of Linalool Against Clinically Relevant Klebsiella pneumoniae

Antibiotic–adjuvant combinatory therapy serves as a viable treatment option in addressing antibiotic resistance in the clinical setting. This study was carried out to assess and characterize the adjuvant potential and mode of action of linalool against carbapenemase-producing Klebsiella pneumoniae (KPC-KP). Linalool exhibited bactericidal activity alone (11,250 μg/ml) and in combination with meropenem (5,625 μg/ml). Comparative proteomic analysis showed significant reduction in the number of cytoplasmic and membrane proteins, indicating membrane damage in linalool-treated KPC-KP cells. Upregulation of oxidative stress regulator proteins and downregulation of oxidative stress-sensitive proteins indicated oxidative stress. Zeta potential measurement and outer membrane permeability assay revealed that linalool increases the bacterial surface charge as well as the membrane permeability. Intracellular leakage of nucleic acid and proteins was detected upon linalool treatment. Scanning and transmission electron microscopies further revealed the breakage of bacterial membrane and loss of intracellular materials. Linalool induced oxidative stress by generating reactive oxygen species (ROS) which initiates lipid peroxidation, leading to damage of the bacterial membrane. This leads to intracellular leakage, eventually killing the KPC-KP cells. Our study demonstrated that linalool possesses great potential in future clinical applications as an adjuvant along with existing antibiotics attributed to their ability in disrupting the bacterial membrane by inducing oxidative stress. This facilitates the uptake of antibiotics into the bacterial cells, enhancing bacterial killing.

Protective Effect of Mitochondria-Targeted Antioxidants against Inflammatory Response to Lipopolysaccharide Challenge: A Review.

Lipopolysaccharide (LPS), the major component of the outer membrane of Gram-negative bacteria, is the most abundant proinflammatory agent. Considerable evidence indicates that LPS challenge inescapably causes oxidative stress and mitochondrial dysfunction, leading to cell and tissue damage. Increased mitochondrial reactive oxygen species (mtROS) generation triggered by LPS is known to play a key role in the progression of the inflammatory response. mtROS at excessive levels impair electron transport chain functioning, reduce the mitochondrial membrane potential, and initiate lipid peroxidation and oxidative damage of mitochondrial proteins and mtDNA. Over the past 20 years, a large number of mitochondria-targeted antioxidants (mito-AOX) of different structures that can accumulate inside mitochondria and scavenge free radicals have been synthesized. Their protective role based on the prevention of oxidative stress and the restoration of mitochondrial function has been demonstrated in a variety of common diseases and pathological states. This paper reviews the current data on the beneficial application of different mito-AOX in animal endotoxemia models, in either in vivo or in vitro experiments. The results presented in our review demonstrate the promising potential of approaches based on mito-AOX in the development of new treatment strategies against Gram-negative infections and LPS per se.

Ferritinophagy-Mediated Ferroptosis Involved in Paraquat-Induced Neurotoxicity of Dopaminergic Neurons: Implication for Neurotoxicity in PD.

Parkinson's disease (PD) is a progressive nervous system disorder. Until now, the molecular mechanism of its occurrence is not fully understood. Paraquat (PQ) was identified as a neurotoxicant and is linked to increased PD risk and PD-like neuropathology. Ferroptosis is recognized as a new form of regulated cell death. Here, we revealed a new underlying mechanism by which ferritinophagy-mediated ferroptosis is involved in PD induced by PQ. The effect of PQ on movement injury in mice was investigated by the bar fatigue and pole-climbing test. SH-SY5Y human neuroblastoma cells were used to evaluate the mechanism of ferroptosis. Our results showed that PQ induced movement injury by causing the decrease in tyrosine hydroxylase in mice. In vitro, PQ significantly caused the iron accumulation in cytoplasm and mitochondria through ferritinophagy pathway induced by NCOA4. Iron overload initiated lipid peroxidation through 12Lox, further inducing ferroptosis by producing lipid ROS. PQ downregulated SLC7A11 and GPX4 expression and upregulated Cox2 expression significantly, which were important markers in ferroptosis. Fer-1, an inhibitor of ferroptosis, could significantly ameliorate the ferroptosis induced by PQ. Meanwhile, Bcl2, Bax, and p-38 were involved in apoptosis induced by PQ. In conclusion, ferritinophagy-mediated ferroptosis pathway played an important role in PD occurrence. Bcl2/Bax and P-p38/p38 pathways mediated the cross-talk between ferroptosis and apoptosis induced by PQ. These data further demonstrated the complexity of PD occurrence. The inhibition of the ferroptosis and apoptosis together may be a new strategy for the prevention of neurotoxicity or PD in the future.

Antimicrobial activity and mode of action of terpene linalyl anthranilate against carbapenemase-producing Klebsiella pneumoniae

Mining of plant-derived antimicrobials is the major focus at current to counter antibiotic resistance. This study was conducted to characterize the antimicrobial activity and mode of action of linalyl anthranilate (LNA) against carbapenemase-producing Klebsiella pneumoniae (KPC-KP). LNA alone exhibited bactericidal activity at 2.5% (V/V), and in combination with meropenem (MPM) at 1.25% (V/V). Comparative proteomic analysis showed a significant reduction in the number of cytoplasmic and membrane proteins, indicating membrane damage in LNA-treated KPC-KP cells. Up-regulation of oxidative stress regulator proteins and down-regulation of oxidative stress-sensitive proteins indicated oxidative stress. Zeta potential measurement and outer membrane permeability assay revealed that LNA increases both bacterial surface charge and membrane permeability. Ethidium bromide influx/efflux assay showed increased uptake of ethidium bromide in LNA-treated cells, inferring membrane damage. Furthermore, intracellular leakage of nucleic acid and proteins was detected upon LNA treatment. Scanning and transmission electron microscopies again revealed the breakage of bacterial membrane and loss of intracellular materials. LNA was found to induce oxidative stress by generating reactive oxygen species (ROS) that initiate lipid peroxidation and damage the bacterial membrane. In conclusion, LNA generates ROS, initiates lipid peroxidation, and damages the bacterial membrane, resulting in intracellular leakage and eventually killing the KPC-KP cells.

The Structural Integrity of the Model Lipid Membrane during Induced Lipid Peroxidation: The Role of Flavonols in the Inhibition of Lipid Peroxidation.

The structural integrity, elasticity, and fluidity of lipid membranes are critical for cellular activities such as communication between cells, exocytosis, and endocytosis. Unsaturated lipids, the main components of biological membranes, are particularly susceptible to the oxidative attack of reactive oxygen species. The peroxidation of unsaturated lipids, in our case 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), induces the structural reorganization of the membrane. We have employed a multi-technique approach to analyze typical properties of lipid bilayers, i.e., roughness, thickness, elasticity, and fluidity. We compared the alteration of the membrane properties upon initiated lipid peroxidation and examined the ability of flavonols, namely quercetin (QUE), myricetin (MCE), and myricitrin (MCI) at different molar fractions, to inhibit this change. Using Mass Spectrometry (MS) and Fourier Transform Infrared Spectroscopy (FTIR), we identified various carbonyl products and examined the extent of the reaction. From Atomic Force Microscopy (AFM), Force Spectroscopy (FS), Small Angle X-Ray Scattering (SAXS), and Electron Paramagnetic Resonance (EPR) experiments, we concluded that the membranes with inserted flavonols exhibit resistance against the structural changes induced by the oxidative attack, which is a finding with multiple biological implications. Our approach reveals the interplay between the flavonol molecular structure and the crucial membrane properties under oxidative attack and provides insight into the pathophysiology of cellular oxidative injury.

Astaxanthin Protects PC12 Cells against Homocysteine- and Glutamate-Induced Neurotoxicity

Memory impairment has been shown to be associated with glutamate (Glu) excitotoxicity, homocysteine (Hcy) accumulation, and oxidative stress. We hypothesize that Glu and Hcy could damage neuronal cells, while astaxanthin (ATX) could be beneficial to alleviate the adverse effects. Using PC12 cell model, we showed that Glu and Hcy provoked a huge amount of reactive oxygen species (ROS) production, causing mitochondrial damage at EC50 20 and 10 mm, respectively. The mechanisms of action include: (1) increasing calcium influx; (2) producing ROS; (3) initiating lipid peroxidation; (4) causing imbalance of the Bcl-2/Bax homeostasis; and (5) activating cascade of caspases involving caspases 12 and 3. Conclusively, the damages caused by Glu and Hcy to PC12 cells can be alleviated by the potent antioxidant ATX.

Effect of Cigarette Smoking on Selected Antioxidant Enzymes and Oxidative Stress Biomarkers

Introduction: Cigarette Smoking (CS) is the single greatest preventable cause of disease and death and is rich in Reactive Oxygen and Nitrogen Species (ROS and RNS). These can cause the production of other free radicals, which, in turn, initiate lipid peroxidation and cause several diseases. Free radical scavenger enzymes namely Superoxide Dismutase (SOD), Catalase (CAT) and Glutathione Peroxidase (GPx) represent the enzymatic part that have the ability to inhibit oxidative stress by scavenging the highly destructive free radicals. Aim: To study the effect of CS on selected antioxidant enzymes and oxidative stress biomarkers. Materials and Methods: A case control study was conducted from September 2016 to September 2019 in which total of 284 healthy (without any systemic diseases) cigarette smokers (cases) in the age group of 18-60 years compared with age and sex matched 284 nonsmokers (controls) were included in the study. Estimation of serum 8-hydroxydeoxyguanosine (8-OHdG) by Enzyme Linked Immunosorbant Assay (ELISA), Malondialdehyde (MDA) by Thiobarbuturic Acid Reactive Substances (TBARS), SOD by water soluble tetrazolium salt 1, GPx and CAT by colorimetric method. The analysis was carried out using the SPSS 19.0.2 program for windows. Unpaired t-test and one-way ANOVA were used to analyse all the data for statistical significance. Results: The mean Serum MDA and 8-OHdG levels were significantly raised 7.47±1.84, 63.41±22.44 as compared to nonsmokers (3.90±1.03, 40.04±20.14) and serum SOD, Gpx and CAT levels were decreased 62.55±19.97, 44.45±16.60 and 12.92±10.16 in cigarette smokers as compared to nonsmokers 274.04±68.37, 208.56±75.63 and 127.82±18.68, respectively. These differences were also found to be statistically significant in cigarette smokers according to duration and number of cigarette smoked at the level of <0.05. Conclusion: Cigarette Smoking, especially long-term smoking may leads to significant changes in the enzymatic antioxidant defense systems of smokers. Discontinuation of smoking and general awareness needs to be created to minimise the risk of smoking related diseases.

Активность окислительных процессов при эндометрите у крыс

Введение. Проблема лечения эндометрита связана в первую очередь с трудностями своевременной дифференциальной диагностики и отсутствием четких клинико-лабораторных критериев. Женщины с хроническим эндометритом в анамнезе даже при условии прегравидарной подготовки составляют группу высокого риска по развитию акушерских и перинатальных осложнений, причиной которых является внутриматочная инфекция. Возбудителями являются прежде всего микроорганизмы, поражающие цилиндрический эпителий канала шейки матки: гонококки и хламидии, мико- и уреаплазмы, которые снижают защитные свойства шеечной слизи, что облегчает распространение восходящей инфекции. Цель исследования -- поиск значимых лабораторных критериев диагностики эндометрита в эксперименте. Методика. Опыты проведены на крысах Wistar, массой 180-200 г. Эндометрит моделировали путем ретроградного введения взвеси аутокалла в полость матки с помощью спринцевания. Маркерами окислительных процессов в организме были выбраны показатели перекисного окисления липидов и окислительной модификации белков. Активность перекисного окисления липидов оценивали по содержанию в плазме крови диеновых и триеновых конъюгатов и оснований Шиффа. Уровень окислительной модификации белков изучали в реакции взаимодействия окисленных аминокислотных остатков белков плазмы с 2,4-динитро-фенилгидразином с образованием альдегид- и кетондинитрофенилгидразонов основного и нейтрального характера, которые регистрировали спектрофотометрически. Результаты. Показано, что у крыс с эндометритом возрастало количество инициальных и конечных продуктов перекисного окисления липидов. При оценке активности окислительной модификации белков в плазме крови показано повышение концентрация карбонильных производных окисленных белков нейтрального и основного характера. Заключение. Выявленный эффект может быть опосредован повышенным уровнем активных форм кислорода, образующихся при действии бактериальной флоры, а также защитной реакцией нейтрофилов, реагирующих на появление антигенных агентов. Можно полагать, что под воздействием продуктов перекисного окисления липидов и окислительной модификации белков происходит повреждение мембран клеток эндометрия, что может быть одной из причин расстройства репродукции, синдрома хронической тазовой боли и развития бесплодия. Данные могут быть использованы для объективизации критериев и ранней лабораторной диагностики эндометрита. The challenge of treating endometritis is associated primarily with the difficulty of timely differential diagnosis and the absence of distinct clinical and laboratory criteria. Women with a history of chronic endometritis, even with a pregravid preparation, constitute a high-risk group for the development of obstetric and perinatal complications caused by intrauterine infection. The pathogens are primarily microorganisms that affect the cylindrical epithelium of cervical canal, gonococci, chlamydia, myco- and ureaplasmas, which impair protective properties of the cervical mucus and facilitate the spread of ascending infection. The aim of the study was experimental searching for significant and reliable laboratory criteria for the diagnosis of endometritis. Methods. Experiments were performed on Wistar female rats weighing 180-200 g. Animals were divided into the groups of intact animals and experimental animals with endometritis induced by retrograde injection of auto feces suspension into the uterine cavity by douching. Markers of oxidative processes included products of lipid peroxidation (LP) (triene and diene conjugates and Schiff bases) and protein oxidation (protein carbonyls) in rat plasma. Results. Plasma concentrations of initial and final LP products as well as of neutral and basic carbonylated proteins were increased in rats with experimental endometritis. Conclusion. The observed effect of experimental endometritis was apparently due to increased production of reactive oxygen species by the bacterial flora administered into the rat uterine cavity. In addition, this effect could result from the protective response of neutrophils to antigenic agents. Apparently, both LP products and oxidation-modified proteins damage cell membranes including endometrial membranes, which may cause reproductive disorders, chronic pelvic pain, and infertility. In future, after clinical studies, these indexes could be used to enhance objective and early laboratory diagnosis of endometritis.

Influence of 10-(6-plastoquinonyl) decyltriphenylphosphonium on free-radical homeostasis in the heart and blood serum of rats with streptozotocin-induced hyperglycemia.

BACKGROUNDIt is known that under conditions of tissue tolerance to insulin, observed during type 2 diabetes mellitus (DM2), there is an increased production of reactive oxygen species. Moreover, the free radicals can initiate lipid peroxidation (LPO) in lipoprotein particles. The concentration of LPO products can influence the state of insulin receptors, repressing their hormone connection activity, which is expressed as a reduction of the glucose consumption by cells. It is possible that reduction in glucose concentration during administration of 10-(6-plastoquinonyl) decyltriphenylphosphonium (SkQ1) to rats with DM2 may be related to the antioxidant properties of this substance.AIMTo establish the influence of SkQ1 on free-radical homeostasis in the heart and blood serum of rats with streptozotocin-induced hyperglycemia.METHODSTo induce hyperglycemia, rats were fed a high-fat diet for 1 mo and then administered two intra-abdominal injections of streptozotocin with a 7-d interval at a 30 mg/kg of animal weight dose with citrate buffer equal to pH 4.4. SkQ1 solution was administered intraperitoneally at a 1250 nmol/kg dose per day. Tissue samples were taken from control animals, animals with experimental hyperglycemia, rats with streptozotocin-induced glycemia that were administered SkQ1 solution, animals housed under standard vivarium conditions that were administered SkQ1, rats that were administered intraperitoneally citrate buffer equal to pH 4.4 once a week during 2 wk after 1-mo high-fat diet, and animals that were administered intraperitoneally with appropriate amount of solution without SkQ1 (98% ethanol diluted eight times with normal saline solution). To determine the intensity of free radical oxidation and total antioxidant activity, we used the biochemiluminescence method. Aconitate hydratase (AH), superoxide dismutase, and catalase activities were estimated using the Hitachi U-1900 spectrophotometer supplied with software. The amount of citrate was determined by means of the Natelson method. Real-time polymerase chain reaction was carried out using an amplifier ANK-32.RESULTSIt was found that the mitochondrial-directed antioxidant elicits decrease of biochemiluminescence parameter values that increase by pathology as well as the levels of primary products of LPO, such as diene conjugates and carbonyl compounds, which indicate intensity of free radical oxidation. At the same time, the activity of AH, considered a crucial target of free radicals, which decreased during experimental hyperglycemia, increased. Apparently, increasing activity of AH influenced the speed of citrate utilization, whose concentration decreased after administering SkQ1 by pathology. Moreover, the previously applied anti-oxidant during hyperglycemia influenced the rate of antioxidant system mobilization. Thus, superoxide dismutase and catalase activity, as well as the level of gene transcript under influence of SkQ1 at pathology, were changing to the direction of control groups values.CONCLUSIONAccording to the results of performed research, SkQ1 can be considered a promising addition to be included in antioxidant therapy of DM2.

Identification of lead-produced lipid hydroperoxides in human HepG2 cells and protection using rosmarinic and ascorbic acids with a reference to their regulatory roles on Nrf2-Keap1 antioxidant pathway

Lead (Pb) is one of the toxic heavy metals that have several toxicological implications including cytotoxicities and oxidative stress. The release of reactive oxygen species (ROS) usually initiates lipid peroxidation and resulting in inflammation and tissue injury. However, the detailed identification of the Pb-produced lipid hydroperoxides has received little attention. Furthermore, the mechanisms behind such effects are less informed. Therefore, this study firstly investigated Pb-produced lipid hydroperoxides in human HepG2 cells using LC/MS. The effects of Pb on the antioxidant enzymes were additionally examined using qPCR and their dependent activities. As a protection trial, the ameliorative effects of rosmarinic (RMA) and ascorbic (ASA) acids on Pb-induced cytotoxicity and oxidative stress and their regulatory effects on Nrf2/Keap1 pathway were investigated. The achieved results confirmed cytotoxicity and oxidative damage of Pb on HepG2 cells. In addition, 20 lipid hydroperoxides (LOOH) were identified including 11 phosphatidylcholine hydroperoxides (PCOOH), 5 triacylglycerol hydroperoxides (TGOOH) and 4 cholesteryl ester hydroperoxides (CEOOH). The most dominant LOOH species were PCOOH 34:2, PCOOH 34:3, PCOOH 38:7, TGOOH 60:14, TGOOH 60:15, CEOOH 18:3 and CEOOH 20:4. Pb significantly downregulated Nrf2-regulated antioxidant enzymes at both the pretranscriptional and functional levels. Co-exposure of HepG2 cells to RMA and ASA significantly reduced Pb-produced adverse outcomes. This protection occurred via activation Nrf2-Keap1 antioxidant pathway.

Enzyme-Driven Membrane-Targeted Chimeric Peptide for Enhanced Tumor Photodynamic Immunotherapy.

Here, a protein farnesyltransferase (PFTase)-driven plasma membrane (PM)-targeted chimeric peptide, PpIX-C6-PEG8-KKKKKKSKTKC-OMe (PCPK), was designed for PM-targeted photodynamic therapy (PM-PDT) and enhanced immunotherapy via tumor cell PM damage and fast release of damage-associated molecular patterns (DAMPs). The PM targeting ability of PCPK originates from the cellular K-Ras signaling, which occurs exclusively to drive the corresponding proteins to PM by PFTase. With the conjugation of the photosensitizer protoporphyrin IX (PpIX), PCPK could generate cytotoxic reactive oxygen species to deactivate membrane-associated proteins, initiate lipid peroxidation, and destroy PM with an extremely low concentration (1 μM) under light irradiation. The specific PM damage further induced the fast release of DAMPs (high-mobility group box 1 and ATP), resulting in antitumor immune responses stronger than those of conventional cytoplasm-localized PDT. This immune-stimulating PM-PDT strategy also exhibited the inhibition effect for distant metastatic tumors when combined with programmed cell death receptor 1 blockade therapy.

The Relationship between Lipid Peroxidation and Microviscosity in Phosphatidylcholine Liposomes. The Effects of a Plant Antioxidant and a Protein

Abstract—The influence of lipid peroxidation on the structure of biomembranes and liposomes has been studied for many years; however, there are still a number of unexplained issues that require additional study. In particular, there are contradictions in the assessment of the state of the structure of deep-lying membrane lipids during the development of lipid peroxidation. In this work, we carried out targeted studies of changes in the microviscosity of a lipid component by the EPR method using a spin probe (16-doxyl-stearic acid) in the process of initiated lipid peroxidation in liposomes obtained from phosphatidylcholine and phosphatidylcholine with a plant antioxidant additive and encapsulation in a protein shell at two temperatures, physiological (37°C) and elevated (60°C). It has been found that the development of lipid peroxidation in all experiments is accompanied by an increase in the microviscosity of deep-lying layers of lipids, which is directly proportional to the degree of development of the lipid peroxidation. This effect is mainly due to an increase in the relative content of saturated fatty acids in lipids of liposomes, although new structural forms of the oxidized lipids may also make some contribution to it. Using dynamic light scattering and atomic force microscopy it has been shown that lipid peroxidation causes an increase in the average diameter and volume of individual liposomes and an increase in the absolute value of their negative zeta potential. A plant antioxidant and a protein inhibit this process.

Malondialdehyde and advanced oxidation protein products are not increased in psoriasis: a controlled study

This study investigated oxidative stress in patients with psoriasis of low and medium disease activity. We measured advanced oxidation protein products (AOPP) and malondialdehyde (MDA) in plasma using UV-spectrophotometry and high performance liquid chromatography connected to a fluorescence detector in 84 patients and 84 matched healthy subjects. AOPP is a marker of protein oxidation due to inflammation, whereas MDA is a hydroxyl radical initiated lipid peroxidation product. Clinico-demographic variables including age, gender, disease severity, and fatigue were assessed in relation to AOPP and MDA. Disease severity was evaluated with the Psoriasis Area and Severity Index and the Dermatology Life Quality Index. Median (interquartile range, IQR) AOPP concentrations were 66µmol/l (IQR 54-102) in patients and 69µmol/l (IQR 55-87) in healthy subjects (P = 0.75). Median plasma MDA concentrations were significantly lower in patients than in healthy subjects (0.68µM, IQR 0.54-0.85 vs. 0.76µM, IQR 0.60-0.97; P = 0.03). Plasma levels of AOPP and MDA did not indicate oxidative stress in patients with mild psoriasis. Higher AOPP concentrations were associated with male gender, high body mass index, and high hemoglobin values. Elevated MDA concentrations were associated with advanced age and male gender. No associations with disease severity were detected. Although, the two selected biomarkers do not provide a complete measure of oxidative damage, our study demonstrates that a number of physiological and methodological factors influence the levels of MDA and AOPP. Such methodological issues are important to consider when interpreting results using these biomarkers in patients with psoriasis.