Intracellular Antioxidant Research Articles

Bismuth Oxide (Bi2O3) Nanoparticles Cause Selective Toxicity in a Human Endothelial (HUVE) Cell Line Compared to Epithelial Cells.

A review of recent literature suggests that bismuth oxide (Bi2O3, referred to as B in this article) nanoparticles (NPs) elicit an appreciable response only after a concentration above 40-50 µg/mL in different cells all having an epithelial origin, to the best of our knowledge. Here, we report the toxicological profile of Bi2O3 NPs (or BNPs) (71 ± 20 nm) in a human endothelial cell (HUVE cell line) in which BNPs exerted much steeper cytotoxicity. In contrast to a high concentration of BNPs (40-50 µg/mL) required to stimulate an appreciable toxicity in epithelial cells, BNPs induced 50% cytotoxicity in HUVE cells at a very low concentration (6.7 µg/mL) when treated for 24 h. BNPs induced reactive oxygen species (ROS), lipid peroxidation (LPO), and depletion of the intracellular antioxidant glutathione (GSH). BNPs also induced nitric oxide (NO,) which can result in the formation of more harmful species in a fast reaction that occurs with superoxide (O2•-). Exogenously applied antioxidants revealed that NAC (intracellular GSH precursor) was more effective than Tiron (a preferential scavenger of mitochondrial O2•-) in preventing the toxicity, indicating ROS production is extra-mitochondrial. Mitochondrial membrane potential (MMP) loss mediated by BNPs was significantly less than that of exogenously applied oxidant H2O2, and MMP loss was not as intensely reduced by either of the antioxidants (NAC and Tiron), again suggesting BNP-mediated toxicity in HUVE cells is extra-mitochondrial. When we compared the inhibitory capacities of the two antioxidants on different parameters of this study, ROS, LPO, and GSH were among the strongly inhibited biomarkers, whereas MMP and NO were the least inhibited group. This study warrants further research regarding BNPs, which may have promising potential in cancer therapy, especially via angiogenesis modulation.

Protocol for a feasibility randomized controlled trial to evaluate the efficacy, safety and tolerability of N-acetylcysteine in reducing adverse drug reactions among adults treated for multidrug-resistant tuberculosis in Tanzania

BackgroundAdverse drug reactions (ADRs) frequently occur in patients using second-line anti-tuberculosis medicine for treatment of multidrug resistant tuberculosis (MDR-TB). ADRs contribute to treatment interruptions which can compromise treatment response and risk acquired drug resistance to critical newer drugs such as bedaquiline, while severe ADRs carry considerable morbidity and mortality. N-acetylcysteine (NAC) has shown promise in reducing ADRs for medications related to TB in case series or randomized controlled trials in other medical conditions, yet evidence is lacking in MDR-TB patients. TB endemic settings have limited capacity to conduct clinical trials. We designed a proof-of-concept clinical trial primarily to explore the preliminary evidence on the protective effect of NAC among people treated for MDR-TB with second-line anti-TB medications.MethodsThis is a proof-of-concept randomized open label clinical trial with 3 treatment arms including a control arm, an interventional arm of NAC 900 mg daily, and an interventional arm of NAC 900 mg twice-daily administered during the intensive phase of MDR-TB treatment. Patients initiating MDR-TB treatment will be enrolled at Kibong’oto National Center of Excellence for MDR-TB in the Kilimanjaro region of Tanzania. The minimum anticipated sample size is 66; with 22 participants in each arm. ADR monitoring will be performed at baseline and daily follow-up over 24 weeks including blood and urine specimen collection for hepatic and renal function and electrolyte abnormalities, and electrocardiogram. Sputum will be collected at baseline and monthly thereafter and cultured for mycobacteria as well as assayed for other molecular targets of Mycobacterium tuberculosis. Adverse drug events will be analysed over time using mixed effect models. Mean differences between arms in change of the ADRs from baseline (with 95% confidence intervals) will be derived from the fitted model.DiscussionGiven that NAC promotes synthesis of glutathione, an intracellular antioxidant that combats the impact of oxidative stress, it may protect against medication induced oxidative damage in organs such as liver, pancreas, kidney, and cells of the immune system. This randomized controlled trial will determine if NAC leads to fewer ADRs, and if this protection is dose dependent. Fewer ADRs among patients treated with MDR-TB may significantly improve treatment outcomes for multidrug regimens that necessitate prolonged treatment durations. Conduct of this trial will set the needed infrastructure for clinical trials.Trial registrationPACTR202007736854169 Registered 03 July 2020

Response mechanism of chloroplast ROS signaling to radon exposure in Tillandsia usneoides as an air pollution sensor

This study analyzed the interaction between CO2 and Rn absorption in Tillandsia usneoides to reveal the influence of aerial plants on radon (Rn) absorption. Chloroplast proteomics and transcriptomics techniques were used to analyze the molecular mechanism of the response of T. usneoides to Rn exposure. The CO2 and Rn absorption were highest under the following conditions: Day 25 °C; Night 15 °C; Light intensity 2500 lux; Light duration 10 h. The CO2 exchange channels were one point of entry for the absorbed Rn. Rn exposure significantly increased the enzyme activities of leaf antioxidant and AsA-GSH cycle pathways. Overall, 370 differentially expressed proteins (114 upregulated; 256 downregulated) were identified in the chloroplast. Rn exposure interfered with the expression levels of critical proteins in the electron transport chain of the photosystems and in the REDOX homeostasis of chloroplasts, leading to 1.78-fold increases in the chloroplast H2O2 content. A total of 3440 differentially regulated genes (up 3255; down 185) were identified using transcriptomic analysis. Upregulation of the intracellular antioxidant enzyme system and the AsA-GSH cycle pathway enhanced the antioxidant capacity of leaves. These responses effectively circumvented the peroxidation damage that would be caused by ROS accumulation induced by Rn exposure.

Glial Glutamate Transporter-Mediated Plasticity: System xc-/xCT/SLC7A11 and EAAT1/2 in Brain Diseases.

Glial cells play an essential role in the complex function of the nervous system. In particular, astrocytes provide nutritive support for neuronal cells and are involved in regulating synaptic transmission. Oligodendrocytes ensheath axons and support information transfer over long distances. Microglial cells constitute part of the innate immune system in the brain. Glial cells are equipped with the glutamate-cystine-exchanger xCT (SLC7A11), the catalytic subunit of system xc-, and the excitatory amino acid transporter 1 (EAAT1, GLAST) and EAAT2 (GLT-1). Thereby, glial cells maintain balanced extracellular glutamate levels that enable synaptic transmission and prevent excitotoxic states. Expression levels of these transporters, however, are not fixed. Instead, expression of glial glutamate transporters are highly regulated in reaction to the external situations. Interestingly, such regulation and homeostasis is lost in diseases such as glioma, (tumor-associated) epilepsy, Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis or multiple sclerosis. Upregulation of system xc- (xCT or SLC7A11) increases glutamate export from the cell, while a downregulation of EAATs decreases intracellular glutamate import. Occurring simultaneously, these reactions entail excitotoxicity and thus harm neuronal function. The release of glutamate via the antiporter system xc- is accompanied by the import of cystine-an amino acid essential in the antioxidant glutathione. This homeostasis between excitotoxicity and intracellular antioxidant response is plastic and off-balance in central nervous system (CNS) diseases. System xc- is highly expressed on glioma cells and sensitizes them to ferroptotic cell death. Hence, system xc- is a potential target for chemotherapeutic add-on therapy. Recent research reveals a pivotal role of system xc- and EAAT1/2 in tumor-associated and other types of epilepsy. Numerous studies show that in Alzheimer's disease, amyotrophic lateral sclerosis and Parkinson's disease, these glutamate transporters are dysregulated-and disease mechanisms could be interposed by targeting system xc- and EAAT1/2. Interestingly, in neuroinflammatory diseases such as multiple sclerosis, there is growing evidence for glutamate transporter involvement. Here, we propose that the current knowledge strongly suggest a benefit from rebalancing glial transporters during treatment.

Pancreatic β-cell dysfunction in type 2 diabetes: Implications of inflammation and oxidative stress.

Insulin resistance and pancreatic β-cell dysfunction are major pathological mechanisms implicated in the development and progression of type 2 diabetes (T2D). Beyond the detrimental effects of insulin resistance, inflammation and oxidative stress have emerged as critical features of T2D that define β-cell dysfunction. Predominant markers of inflammation such as C-reactive protein, tumor necrosis factor alpha, and interleukin-1β are consistently associated with β-cell failure in preclinical models and in people with T2D. Similarly, important markers of oxidative stress, such as increased reactive oxygen species and depleted intracellular antioxidants, are consistent with pancreatic β-cell damage in conditions of T2D. Such effects illustrate a pathological relationship between an abnormal inflammatory response and generation of oxidative stress during the progression of T2D. The current review explores preclinical and clinical research on the patho-logical implications of inflammation and oxidative stress during the development of β-cell dysfunction in T2D. Moreover, important molecular mechanisms and relevant biomarkers involved in this process are discussed to divulge a pathological link between inflammation and oxidative stress during β-cell failure in T2D. Underpinning the clinical relevance of the review, a systematic analysis of evidence from randomized controlled trials is covered, on the potential therapeutic effects of some commonly used antidiabetic agents in modulating inflammatory makers to improve β-cell function.

Nature-Inspired Bioactive Compounds: A Promising Approach for Ferroptosis-Linked Human Diseases?

Ferroptosis is a type of cell death driven by iron overload and lipid peroxidation. It is considered a key mechanism in the development of various diseases such as atherosclerosis, Alzheimer, diabetes, cancer, and renal failure. The redox status of cells, such as the balance between intracellular oxidants (lipid peroxides, reactive oxygen species, free iron ions) and antioxidants (glutathione, glutathione Peroxidase 4), plays a major role in ferroptosis regulation and constitutes its principal biomarkers. Therefore, the induction and inhibition of ferroptosis are promising strategies for disease treatments such as cancer or neurodegenerative and cardiovascular diseases, respectively. Many drugs have been developed to exert ferroptosis-inducing and/or inhibiting reactions, such as erastin and iron-chelating compounds, respectively. In addition, many natural bioactive compounds have significantly contributed to regulating ferroptosis and ferroptosis-induced oxidative stress. Natural bioactive compounds are largely abundant in food and plants and have been for a long time, inspiring the development of various low-toxic therapeutic drugs. Currently, functional bioactive peptides are widely reported for their antioxidant properties and application in human disease treatment. The scientific evidence from biochemical and in vitro tests of these peptides strongly supports the existence of a relationship between their antioxidant properties (such as iron chelation) and ferroptosis regulation. In this review, we answer questions concerning ferroptosis milestones, its importance in physiopathology mechanisms, and its downstream regulatory mechanisms. We also address ferroptosis regulatory natural compounds as well as provide promising thoughts about bioactive peptides.

Encapsulation of lycopene into electrospun nanofibers from whey protein isolate-Tricholoma lobayense polysaccharide complex stabilized emulsions: Structural characterization, storage stability, in vitro release, and cellular evaluation

In this study, lycopene-loaded nanofibers were successfully fabricated by electrospinning of oil-in-water (O/W) emulsions stabilized by whey protein isolate-polysaccharide TLH-3 (WPI–TLH-3) complexes. The lycopene encapsulated in the emulsion-based nanofibers exhibited enhanced photostability and thermostability, and achieved improved targeted small intestine-specific release. The release of lycopene from the nanofibers followed Fickian diffusion mechanism in simulated gastric fluid (SGF) and first-order model in simulated intestinal fluid (SIF) with the enhanced release rates. The bioaccessibility and cellular uptake efficiency of lycopene in micelles by Caco-2 cells after in vitro digestion were significantly improved. The intestinal membrane permeability and transmembrane transport efficiency of lycopene in micelles across Caco-2 cells monolayer were greatly elevated, thus promoting the effective absorption and intracellular antioxidant activity of lycopene. This work opens a potential approach for electrospinning of emulsions stabilized by protein–polysaccharide complexes as a novel delivery system for liposoluble nutrients with enhanced bioavailability in functional food industries.

Ceria Nanoparticles as Copper Chaperones that Activate SOD1 for Synergistic Antioxidant Therapy to Treat Ischemic Vascular Diseases.

All exogenous nanomaterials undergo rapid biotransformation once injected into the body and fall short of executing the intended purpose. Here,it is reported that copper-deposited ceria nanoparticles (CuCe NPs) exhibit enhanced antioxidant effects overpristine ceria nanoparticles, as the released copper buffers the depletion of glutathione while providing the bioavailable copper as a cofactor for the antioxidant enzyme, superoxide dismutase 1. The upregulated intracellular antioxidants along with the ceria nanoparticles synergistically scavenge reactive oxygen species and promote anti-inflammation and M2 polarization of macrophages by modulating signal transducer and activator of transcription 1 and 6 (STAT1 and STAT6). The therapeutic effect of CuCe NPs is demonstrated in ischemic vascular diseases (i.e., murine models of hindlimb ischemia and myocardial infarction) in which the copper-deposition affords increased perfusion and alleviation in tissue damage. The results provide rationale that metal oxide nanomaterials can be designed in a way to induce the upregulation of specific biological factors for optimal therapeutic performance.

Nanofabrication of cobalt-tellurium using Allium sativum extract and its protective efficacy against H2O2-induced oxidative damage in HaCaT cells

Allium sativum (A. sativum)is well known for its therapeutic and culinary uses. Because of their high medicinal properties, the clove extract was selected to synthesize cobalt-tellurium nanoparticles. The aim of the study was to evaluate the protective activity of the nanofabricated cobalt-tellurium using A. sativum (Co-Tel-As-NPs) against H2O2-induced oxidative damage in HaCaT cells. Synthesized Co-Tel-As-NPs were analyzed using UV–Visible spectroscopy, FT-IR, EDAX, XRD, DLS, and SEM. Various concentrations of Co-Tel-As-NPs were used as a pretreatment on HaCaT cells before H2O2 was added. Then, the cell viability and mitochondrial damage were compared between pretreated and untreated control cells using an array of assays (MTT, LDH, DAPI, MMP, and TEM), and the intracellular ROS, NO, and antioxidant enzyme production were examined. In the present research, Co-Tel-As-NPs at different concentrations (0.5, 1.0, 2.0, and 4.0μg/mL) were tested for toxicity using HaCaT cells. Furthermore, the effect of H2O2 on the viability of HaCaT cells was evaluated using the MTT assay for Co-Tel-As-NPs. Among those, Co-Tel-As-NPs at 4.0 μg/mL showed notable protection; with the same treatment, cell viability was discovered to be 91% and LDH leakage was also significantly decreased. Additionally, the measurement of mitochondrial membrane potential was significantly decreased by Co-Tel-As-NPs pretreatment against H2O2. The recovery of the condensed and fragmented nuclei brought about by the action of Co-Tel-As-NPs was identified using DAPI staining. TEM examination of the HaCaT cells revealed that the Co-Tel-As-NPs had a therapeutic effect against H2O2 keratinocyte damage.

Destruction of the cellular antioxidant pool contributes to resveratrol-induced senescence and apoptosis in lung cancer.

Resveratrol (RES) has various pharmacological bioactivities and its anticancer effects in lung cancer have been proven. However, the underlying mechanisms of action of RES in lung cancer remain unclear. This study focused on Nrf2-mediated antioxidant systems in RES-treated lung cancer cells. A549 and H1299 cells were treated with various concentrations of RES at different times. RES decreased cell viability, inhibited cell proliferation, and increased the number of senescent and apoptotic cells in a concentration- and time-dependent manner. Moreover, RES-induced lung cancer cell arrest at the G1 phase was accompanied by changes in apoptotic proteins (Bax, Bcl-2, and cleaved caspase 3). Furthermore, RES induced a senescent phenotype along with changes in senescence-related markers (senescence-associated β-galactosidase activity, p21, and p-γH2AX). More importantly, with prolonged exposure time and increased exposure concentration, intracellular reactive oxygen species (ROS) continuously accumulated, resulting in a decrease in Nrf2 and its downstream antioxidant response elements, including CAT, HO-1, NQO1, and SOD1. Meanwhile, RES-induced ROS accumulation and cell apoptosis were reversed by N-acetyl-l-cysteine treatment. Taken together, these results suggest that RES disturb lung cancer cellular homeostasis by destroying the intracellular antioxidant pool to increase ROS production. Our findings provide a new perspective on RES intervention in lung cancer.

Insights into the antioxidative mechanisms of melatonin in ameliorating chromium-induced oxidative stress-mediated hepatic and renal tissue injuries in male Wistar rats.

Chromium (Cr), a hazardous heavy metal, is toxic to human health and the environment. Severe detrimental effects of Cr on different physiological systems involve oxidative stress. In the current study, sodium dichromate di-hydrate was subcutaneously injected to male Wistar rats at a dose of 5 mg/kg b.w. and experimented up to 14 days to induce alterations in hepatic and renal tissues. Another group of rats was pre-treated with melatonin at three different doses (5, 10, and 20 mg/kg b.w.; orally) and 20 mg/kg b.w. dose was evidenced to provide maximal protection against Cr-induced alterations. The study demonstrated that melatonin efficiently preserved body weight, organ weight, intracellular antioxidant enzymes, and tissue morphology. Furthermore, melatonin was also found to protect organ damage markers, oxidative stress-biomarkers, activities of pro-oxidant enzymes, levels of reactive oxygen species (ROS), nitric oxide (NO), and collagen content through its antioxidative mechanisms. Moreover, melatonin effectively decreased tissue Cr content through its metal-chelating activity. Hence, the present study has established melatonin as a promising antioxidant for conserving the liver and kidney tissues from Cr-induced oxidative damage thereby strengthening the notion that this small indoleamine can act as a future therapeutic against Cr-induced oxidative stress-mediated tissue damage.

Engineering a synergistic antioxidant inhibition nanoplatform to enhance oxidative damage in tumor treatment.

The antioxidant system of tumor cells severely impairs reactive oxygen species (ROS)-mediated tumor therapy. Despite extensive attempts to attenuate the antioxidant capacity by eliminating ROS scavengers such as glutathione (GSH), nicotinamide adenine dinucleotide phosphate (NADPH) over-expressed in the tumor microenvironment can regenerate GSH from glutathione disulfide (GSSG), hence weakening ROS-induced oxidative damage. Therefore, engineering a nanoplatform capable of depleting both NADPH and GSH is extremely significant for improving ROS-mediated tumor treatment. Herein, a synergetic antioxidant inhibition strategy is proposed to attenuate intracellular antioxidant capacity for hypoxic tumor therapy. In this context, both porous Prussian blue nanoparticles (PPB NPs) and cisplatin prodrug [cis-Pt (IV)] in the nanoplatform can oxidize GSH to directly reduce GSH levels, while PPB NPs also enable NADPH depletion by peroxidase-mimicking to impair GSH regeneration. Furthermore, PPB NPs with catalase-mimicking activity catalyze H2O2 decomposition to alleviate tumor hypoxia, thus reducing the generation of GSH and boosting singlet oxygen (1O2) production by Chlorin e6 (Ce6) for enhancing oxidative damage. Experimental results prove that the nanoplatform, denoted as PPB-Ce6-Pt, can induce remarkable tumor cells apoptosis and ferroptosis. Importantly, a simple loading method and the use of Food Drug Administration (FDA)-approved materials make PPB-Ce6-Pt have great potential for practical applications. STATEMENT OF SIGNIFICANCE: The antioxidant system in tumor cells disables ROS-mediated tumor therapy. Besides, extensive attempts aim at depleting GSH without considering their regeneration. Therefore, we developed a synergetic strategy to attenuate intracellular antioxidant capacity for hypoxic tumor therapy. PPB-Ce6-Pt nanoplatform could not only directly reduce GSH levels but also deplete NADPH by peroxidase-mimicking to impair GSH regeneration. In addition, PPB-Ce6-Pt nanoplatform could catalyze H2O2 decomposition to alleviate tumor hypoxia, thus reducing the generation of GSH and boosting 1O2 production by Chlorin e6 (Ce6) for increasing oxidative damage. Then, intracellular ROS boost and redox dyshomeostasis induced remarkable tumor cells apoptosis and ferroptosis. Importantly, a simple loading method and the use of biosafety materials made the nanoplatform have great potential for practical applications.

Melatonin in Dermatologic Allergic Diseases and Other Skin Conditions: Current Trends and Reports.

Melatonin is the main hormone that regulates the sleep cycle, and it is mostly produced by the pineal gland from the amino acid tryptophan. It has cytoprotective, immunomodulatory, and anti-apoptotic effects. Melatonin is also one of the most powerful natural antioxidants, directly acting on free radicals and the intracellular antioxidant enzyme system. Furthermore, it participates in antitumor activity, hypopigmentation processes in hyperpigmentary disorders, anti-inflammatory, and immunomodulating activity in inflammatory dermatoses, maintaining the integrity of the epidermal barrier and thermoregulation of the body. Due predominantly to its positive influence on sleep, melatonin can be used in the treatment of sleep disturbances for those with chronic allergic diseases accompanied by intensive itching (such as atopic dermatitis and chronic spontaneous urticaria). According to the literature data, there are also many proven uses for melatonin in photoprotection and skin aging (due to melatonin's antioxidant effects and role in preventing damage due to DNA repair mechanisms), hyperpigmentary disorders (e.g., melasma) and scalp diseases (such as androgenic alopecia and telogen effluvium).

Dietary Supplements Potentially Target Plasma Glutathione Levels to Improve Cardiometabolic Health in Patients with Diabetes Mellitus: A Systematic Review of Randomized Clinical Trials.

Cardiovascular diseases (CVDs) continue to be the leading cause of death in people with diabetes mellitus. Severely suppressed intracellular antioxidant defenses, including low plasma glutathione (GSH) levels, are consistently linked with the pathological features of diabetes such as oxidative stress and inflammation. In fact, it has already been established that low plasma GSH levels are associated with increased risk of CVD in people with diabetes. Dietary supplements are widely used and may offer therapeutic benefits for people with diabetes at an increased risk of developing CVDs. However, such information remains to be thoroughly scrutinized. Hence, the current systematic review explored prominent search engines, including PubMed and Google Scholar, for updated literature from randomized clinical trials reporting on the effects of dietary supplements on plasma GSH levels in people with diabetes. Available evidence indicates that dietary supplements, such as coenzyme Q10, selenium, curcumin, omega-3 fatty acids, and vitamin E or D, may potentially improve cardiometabolic health in patients with diabetes. Such beneficial effects are related to enhancing plasma GSH levels and reducing cholesterol, including biomarkers of oxidative stress and inflammation. However, available evidence is very limited and additional clinical studies are still required to validate these findings, including resolving issues related to the bioavailability of these bioactive compounds.

Mechanical Regulation of Redox Balance via the Induction of the PIN1/NRF2/ARE Axis in Pancreatic Cancer.

Pancreatic cancer is one of the most lethal malignancies. Desmoplastic stroma and metabolic reprogramming are two hallmarks of pancreatic cancer that support its malignant biological behaviors. However, the underlying mechanism by which the stroma maintain the redox balance remains unclear in pancreatic ductal adenocarcinoma (PDAC). Here, we demonstrated that the physical properties of the stroma could regulate the expression of PIN1 in pancreatic cancer cells. Moreover, we found that hard matrix-cultured pancreatic cancer cells induced the upregulation of PIN1 expression. Since PIN1 maintained redox balance via synergistic activation of NRF2 transcription, PIN1 promoted the expression of NRF2 to induce the expression of intracellular antioxidant response element (ARE)-driven genes. Consequently, the antioxidant stress ability of PDAC was increased, and the intracellular level of reactive oxygen species (ROS) was decreased. Thus, PIN1 is expected to be an important target for the treatment of PDAC, especially PDAC with an exuberant desmoplastic stroma.

Reactive oxygen metabolism in the proliferation of Korean pine embryogenic callus cells promoted by exogenous GSH

Exogenous glutathione (GSH) promotes the proliferation of embryogenic callus (EC) cells in Korean pine in the course of somatic embryogenesis, and reactive oxygen species (ROS) may play an important role in regulating the proliferation of EC cells by exogenous GSH. However, the concrete metabolic response of ROS is unclear. In this study, two cell lines of Korean pine with high proliferative potential 001#-001 (F, Fast proliferative potential cell line is abbreviated as F) and low proliferative potential 001#-010 (S, Slow proliferative potential cell line is abbreviated as S) were used as test materials. The responses of ROS-related enzymes and substances to exogenous GSH and L-Buthionine-sulfoximine (BSO) were investigated in EC cells. The results showed that the exogenous addition of GSH increased the number of early somatic embryogenesis (SEs) in EC cells of both F and S cell lines, decreased the amount of cell death in both cell lines. Exogenous addition of GSH promoted cell division in both cell lines, increased intracellular superoxide dismutase (SOD) and catalase (CAT) activities, inhibited intracellular hydrogen peroxide (H2O2), malondialdehyde (MDA) and nitric oxide (NO) production, and increased NO/ROS ratio. In conclusion, the exogenous GSH promoting the proliferation of Korean pine EC cells, the activity of intracellular antioxidant enzymes was enhanced, the ROS level was reduced, and the resistance of cells to stress was enhanced.

Antioxidant Effect of a Dietary Supplement Containing Fermentative S-Acetyl-Glutathione and Silybin in Dogs with Liver Disease

Oxidative stress is often involved in liver disease progression. Liver is the primary site for the synthesis of glutathione (GSH), the major intracellular antioxidant. GSH erythrocyte concentration can decrease in case of liver damage. So, the use of food supplements with antioxidant capacity has been reported in the veterinary literature. In this case-control study, we tested a new supplement containing S-acetyl-glutathione (SAG), silybin, and other antioxidant ingredients in dogs affected by liver disease. After two weeks of supplement administration, we were able to report a significant increase in the level of erythrocyte GSH in the treated (TRT) group, nearly reaching the physiological limit at the end of the study. In addition, most of the key liver parameters are significantly reduced in the TRT group by the end of the trial. The results of this study support the effectiveness of the tested complementary feed, which may be helpful in managing dogs with liver conditions.

Evaluation of the antimicrobial mechanism of biogenic selenium nanoparticles against Pseudomonas fluorescens

Selenium nanoparticles (SeNPs) can be biosynthesized by most Lactic acid bacteria thereby converting toxic sodium into SeNPs. However, few studies have reported the antimicrobial activity of biogenic SeNPs against Pseudomonas fluorescens which are the main species of psychrotrophic bacteria in raw milk. This study reported the synthesis and characterization of SeNPs from Lactobacillus casei ZK-AS 1.1482, and the antimicrobial mechanism against P. fluorescens ATCC 13525. The synthesized SeNPs were amorphous with sizes ranging from 52 to 103 nm. Fourier transform infrared spectroscopy (FT-IR) spectra showed the presence of proteins, polysaccharides, and lipids on the surface of particles, which evidently stabilized the SeNPs structure and morphology. Energy-dispersive X-ray (EDX) analysis revealed that the nanoparticles contained selenium. In addition, the minimal inhibitory concentration (MIC) of SeNPs against P. fluorescens ATCC 13525 was 0.1 mg ml−1 and the biofilm inhibition rate was 43.52 ± 0.26%. SeNPs decreased the number of living bacteria observed by confocal laser scanning microscopy (CLSM). Meanwhile, after SeNPs treatment, the intracellular adenosine triphosphate (ATP) concentration and antioxidant enzyme activity decreased, the content of reactive oxygen species (ROS) and the malondialdehyde (MDA) content increased, and lipid peroxidation intensified. Real-time fluorescence quantitative PCR (RT-qPCR) assay showed that the expression of flgA, luxR, lapD, MCP, cheA, c-di-GMP, phoB, and pstC gene were down-regulated after SeNPs treatment. The rfbC and DegT/DnrJ/EryC1/StrS gene were significantly up-regulated, indicating that SeNPs could destroy the integrity of cell membrane and thus play an antimicrobial role. Biogenic SeNPs are expected to be developed as an efficient and novel antimicrobial agent for application in the food industry.

Drug-independent NADPH-consuming micelles collaborate with ROS-generator for cascade ferroptosis amplification by impairing redox homeostasis.

Ferroptosis as promising antitumor therapy strategy could be comprised by intracellular antioxidants, especially GSH and thioredoxin (Trx). They are both cofactors of Gpx4, the enzyme catalyzing the production of lipid peroxides to relieve oxidative stress, which drives the acquired ferroptosis resistance in tumors. Herein, the NADPH-consuming micelles are specially designed, which could collaborate with the ROS generating photodynamics therapy (PDT) by depleting intracellular GSH and Trx under hypoxia condition, resulting in ruined redox homeostasis and the final cascade amplified ferroptosis. The tailored micelle was briefly prepared by conjugating hypoxia-sensitive segment p-nitrobenzyl chloroformate (PNZ-Cl) to the hydrophilic chitosan (CS), the resulting micelle was further modified with photosensitizer Ce6 via PEG linkage. When receiving laser irradiation, the photosensitizer would generate ROS and consume oxygen in the meanwhile. The resulting anabatic hypoxia in turns promote the NTR-catalyzed electron-accepting response of micelles, with evidently enhanced NADPH consumption and ultimately ruined redox homeostasis, contributing to cascade amplified ferroptosis with robust ROS. Most importantly, the accompanied immunogenic cell death (ICD) and releasing danger-associated molecular patterns (DAMPs) could boost dendritic cells (DCs) maturation and the subsequent T-cell-mediated profound immune response. Collectively, the work excavates the other biochemical reaction during the hypoxia-sensitive process of C-N-Ce6 by diminishing intracellular GSH and Trx, providing a candidate of ferroptosis inducers against solid tumors.

Multi-scale analysis of nickel ion tolerance mechanism for thermophilic Sulfobacillus thermosulfidooxidans in bioleaching.

Bioleaching is intensively investigated for recovering valuable metals such as Li, Co, Ni and Cu. Nickel ion stress threatens the health of microorganisms when Ni2+ starts to accumulate in the leachate during the bioleaching of materials that are rich in Ni, such as spent lithium-ion batteries. The possible mechanisms underlying the response of S. thermosulfidooxidans to nickel ion stress were analyzed using a multi-scale approach. Under the condition of nickel ion stress, high concentrations of nickel ions were immobilized by extracellular polymeric substances, while concentrations of nickel ions inside the cells remained low. The intracellular adenosine triphosphate (ATP) concentration and H+-ATPase activity increased to maintain normal cell growth and metabolic activities. Scavenging abilities of S. thermosulfidooxidans for hydrogen peroxide and superoxide anion were enhanced to reduce oxidative damage induced by nickel ion stress. There were 734 differentially expressed genes identified by RNA-seq under nickel ion stress. Most of them were involved in oxidative phosphorylation, glutathione metabolism and genetic information processing, responsible for intracellular energy utilization, intracellular antioxidant capacity and DNA damage repair, respectively. The results of this study are of major significance for in-depth understanding of the mechanisms of acidophilic microorganisms' resistance to metal ions.