Cellular Antioxidant System Research Articles

Strigolactones Modulate Cellular Antioxidant Defense Mechanisms to Mitigate Arsenate Toxicity in Rice Shoots.

Metalloid contamination, such as arsenic poisoning, poses a significant environmental problem, reducing plant productivity and putting human health at risk. Phytohormones are known to regulate arsenic stress; however, the function of strigolactones (SLs) in arsenic stress tolerance in rice is rarely investigated. Here, we investigated shoot responses of wild-type (WT) and SL-deficient d10 and d17 rice mutants under arsenate stress to elucidate SLs’ roles in rice adaptation to arsenic. Under arsenate stress, the d10 and d17 mutants displayed severe growth abnormalities, including phenotypic aberrations, chlorosis and biomass loss, relative to WT. Arsenate stress activated the SL-biosynthetic pathway by enhancing the expression of SL-biosynthetic genes D10 and D17 in WT shoots. No differences in arsenic levels between WT and SL-biosynthetic mutants were found from Inductively Coupled Plasma-Mass Spectrometry analysis, demonstrating that the greater growth defects of mutant plants did not result from accumulated arsenic in shoots. The d10 and d17 plants had higher levels of reactive oxygen species, water loss, electrolyte leakage and membrane damage but lower activities of superoxide dismutase, ascorbate peroxidase, glutathione peroxidase and glutathione S-transferase than did the WT, implying that arsenate caused substantial oxidative stress in the SL mutants. Furthermore, WT plants had higher glutathione (GSH) contents and transcript levels of OsGSH1, OsGSH2, OsPCS1 and OsABCC1 in their shoots, indicating an upregulation of GSH-assisted arsenic sequestration into vacuoles. We conclude that arsenate stress activated SL biosynthesis, which led to enhanced arsenate tolerance through the stimulation of cellular antioxidant defense systems and vacuolar sequestration of arsenic, suggesting a novel role for SLs in rice adaptation to arsenic stress. Our findings have significant implications in the development of arsenic-resistant rice varieties for safe and sustainable rice production in arsenic-polluted soils.

Staphylococcal ClpXP protease targets the cellular antioxidant system to eliminate fitness-compromised cells in stationary phase

The transition from growth to stationary phase is a natural response of bacteria to starvation and stress. When stress is alleviated and more favorable growth conditions return, bacteria resume proliferation without a significant loss in fitness. Although specific adaptations that enhance the persistence and survival of bacteria in stationary phase have been identified, mechanisms that help maintain the competitive fitness potential of nondividing bacterial populations have remained obscure. Here, we demonstrate that staphylococci that enter stationary phase following growth in media supplemented with excess glucose, undergo regulated cell death to maintain the competitive fitness potential of the population. Upon a decrease in extracellular pH, the acetate generated as a byproduct of glucose metabolism induces cytoplasmic acidification and extensive protein damage in nondividing cells. Although cell death ensues, it does not occur as a passive consequence of protein damage. Instead, we demonstrate that the expression and activity of the ClpXP protease is induced, resulting in the degeneration of cellular antioxidant capacity and, ultimately, cell death. Under these conditions, inactivation of either clpX or clpP resulted in the extended survival of unfit cells in stationary phase, but at the cost of maintaining population fitness. Finally, we show that cell death from antibiotics that interfere with bacterial protein synthesis can also be partly ascribed to the corresponding increase in clpP expression and activity. The functional conservation of ClpP in eukaryotes and bacteria suggests that ClpP-dependent cell death and fitness maintenance may be a widespread phenomenon in these domains of life.

Comprehensive chemical proteomics analyses reveal that the new TRi-1 and TRi-2 compounds are more specific thioredoxin reductase 1 inhibitors than auranofin

Anticancer drugs that target cellular antioxidant systems have recently attracted much attention. Auranofin (AF) is currently evaluated in several clinical trials as an anticancer agent that targets the cytosolic and mitochondrial forms of the selenoprotein thioredoxin reductase, TXNRD1 and TXNRD2. Recently, two novel TXNRD1 inhibitors (TRi-1 and TRi-2) have been developed that showed anticancer efficacy comparable to AF, but with lower mitochondrial toxicity. However, the cellular action mechanisms of these drugs have not yet been thoroughly studied. Here we used several proteomics approaches to determine the effects of AF, TRi-1 and TRi-2 when used at IC50 concentrations with the mouse B16 melanoma and LLC lung adenocarcinoma cells, as these are often used for preclinical mouse models in evaluation of anticancer drugs. The results demonstrate that TRi-1 and TRi-2 are more specific TXNRD1 inhibitors than AF and reveal additional AF-specific effects on the cellular proteome. Interestingly, AF triggered stronger Nrf2-driven antioxidant responses than the other two compounds. Furthermore, AF affected several additional proteins, including GSK3A, GSK3B, MCMBP and EEFSEC, implicating additional effects on glycogen metabolism, cellular differentiation, inflammatory pathways, DNA replication and selenoprotein synthesis processes. Our proteomics data provide a resource for researchers interested in the multidimensional analysis of proteome changes associated with oxidative stress in general, and the effects of TXNRD1 inhibitors and AF protein targets in particular.

Supramolecular Self‐Assembled DNA Nanosystem for Synergistic Chemical and Gene Regulations on Cancer Cells

AbstractIncorporating multiple molecular interactions within a system to realize the metabolic reprogramming of cancer cells is prospected to be of great potential in cancer therapy. Herein, we report a supramolecular self‐assembled DNA nanosystem, which reprogrammed the cellular antioxidant system via synergistic chemical and gene regulations. In the nanosystem, amphipathic telluroether was coordinated with MnII to self‐assemble into micelle, on which a siNrf2 integrated DNA network was assembled. The great electron‐donating capability of telluroether was revealed to greatly promote MnII‐based Fenton‐like reaction to generate subversive .OH in cancer cells. In response to adenosine triphosphoric acid, the siNrf2 was specially released in cytoplasm for down‐regulating expression of detoxification enzymes, which enhanced chemocatalysis‐mediated oxidative stress in cancer cells, thus significantly suppressing tumor progression.

Supramolecular Self-Assembled DNA Nanosystem for Synergistic Chemical and Gene Regulations on Cancer Cells.

Incorporating multiple molecular interactions within a system to realize the metabolic reprogramming of cancer cells is prospected to be of great potential in cancer therapy. Herein, we report a supramolecular self-assembled DNA nanosystem, which reprogrammed the cellular antioxidant system via synergistic chemical and gene regulations. In the nanosystem, amphipathic telluroether was coordinated with MnII to self-assemble into micelle, on which a siNrf2 integrated DNA network was assembled. The great electron-donating capability of telluroether was revealed to greatly promote MnII -based Fenton-like reaction to generate subversive . OH in cancer cells. In response to adenosine triphosphoric acid, the siNrf2 was specially released in cytoplasm for down-regulating expression of detoxification enzymes, which enhanced chemocatalysis-mediated oxidative stress in cancer cells, thus significantly suppressing tumor progression.

Cytoprotective Peptides from Blue Mussel Protein Hydrolysates: Identification and Mechanism Investigation in Human Umbilical Vein Endothelial Cells Injury.

Cardiovascular disease represents a leading cause of mortality and is often characterized by the emergence of endothelial dysfunction (ED), a physiologic condition that takes place in the early progress of atherosclerosis. In this study, two cytoprotective peptides derived from blue mussel chymotrypsin hydrolysates with the sequence of EPTF and FTVN were purified and identified. Molecular mechanisms underlying the cytoprotective effects against oxidative stress which lead to human umbilical vein endothelial cells (HUVEC) injury were investigated. The results showed that pretreatment of EPTF, FTVN and their combination (1:1) in 0.1 mg/mL significantly reduced HUVEC death due to H2O2 exposure. The cytoprotective mechanism of these peptides involves an improvement in the cellular antioxidant defense system, as indicated by the suppression of the intracellular ROS generation through upregulation of the cytoprotective enzyme heme oxygenase-1. In addition, H2O2 exposure triggers HUVEC damage through the apoptosis process, as evidenced by increased cytochrome C release, Bax protein expression, and the elevated amount of activated caspase-3, however in HUVEC pretreated with peptides and their combination, the presence of those apoptotic stimuli was significantly decreased. Each peptide showed similar cytoprotective effect but no synergistic effect. Taken together, these peptides may be especially important in protecting against oxidative stress-mediated ED.

Glucose 6-P dehydrogenase delays the onset of frailty by protecting against muscle damage.

BackgroundFrailty is a major age‐associated syndrome leading to disability. Oxidative damage plays a significant role in the promotion of frailty. The cellular antioxidant system relies on reduced nicotinamide adenine dinucleotide phosphate (NADPH) that is highly dependent on glucose 6‐P dehydrogenase (G6PD). The G6PD‐overexpressing mouse (G6PD‐Tg) is protected against metabolic stresses. Our aim was to examine whether this protection delays frailty.MethodsOld wild‐type (WT) and G6PD‐Tg mice were evaluated longitudinally in terms of frailty. Indirect calorimetry, transcriptomic profile, and different skeletal muscle quality markers and muscle regenerative capacity were also investigated.ResultsThe percentage of frail mice was significantly lower in the G6PD‐Tg than in the WT genotype, especially in 26‐month‐old mice where 50% of the WT were frail vs. only 13% of the Tg ones (P < 0.001). Skeletal muscle transcriptomic analysis showed an up‐regulation of respiratory chain and oxidative phosphorylation (P = 0.009) as well as glutathione metabolism (P = 0.035) pathways in the G6PD‐Tg mice. Accordingly, the Tg animals exhibited an increase in reduced glutathione (34.5%, P < 0.01) and a decrease on its oxidized form (−69%, P < 0.05) and in lipid peroxidation (4‐HNE: −20.5%, P < 0.05). The G6PD‐Tg mice also showed reduced apoptosis (BAX/Bcl2: −25.5%, P < 0.05; and Bcl‐xL: −20.5%, P < 0.05), lower levels of the intramuscular adipocyte marker FABP4 (−54.7%, P < 0.05), and increased markers of mitochondrial content (COX IV: 89.7%, P < 0.05; Grp75: 37.8%, P < 0.05) and mitochondrial OXPHOS complexes (CII: 81.25%, P < 0.01; CIII: 52.5%, P < 0.01; and CV: 37.2%, P < 0.05). Energy expenditure (−4.29%, P < 0.001) and the respiratory exchange ratio were lower (−13.4%, P < 0.0001) while the locomotor activity was higher (43.4%, P < 0.0001) in the 20‐month‐old Tg, indicating a major energetic advantage in these mice. Short‐term exercise training in young C57BL76J mice induced a robust activation of G6PD in skeletal muscle (203.4%, P < 0.05), similar to that achieved in the G6PD‐Tg mice (142.3%, P < 0.01).ConclusionsGlucose 6‐P dehydrogenase deficiency can be an underestimated risk factor for several human pathologies and even frailty. By overexpressing G6PD, we provide the first molecular model of robustness. Because G6PD is regulated by pharmacological and physiological interventions like exercise, our results provide molecular bases for interventions that by increasing G6PD will delay the onset of frailty.

The Efficacy of a Peptide Product from the Pituitary Gland of &lt;i&gt;Rangifer tarandus&lt;/i&gt; as an Antioxidant Agent Under the Combined Effects of Light Desynchronosis and Depriming Toxicant

The possibility of using methods for determining the oxidative status of an organism (enzymatic and non-enzymatic links of the cellular antioxidant system) to assess the antioxidant properties of peptides of the pituitary gland of the reindeer (Rangifer tarandus) were investigated in an experimental study conducted with a combined effect of factors of different nature on rats: a physical factor — prolonged light desynchronosis (different light modes) and a chemical factor - acute severe poisoning with depriving toxicant (sodium thiopental, LD50). The pharmacological correction of the oxidative status of cells in the animals of the experimental subgroups was carried out with the peptide product of the pituitary gland, intranasally injecting the surviving rats with the bioproduct at a dose of 100 µg/kg, once in the first half of the objective day for 14 days after poisoning with sodium thiopental. The surviving animals of the control groups were similarly injected with saline. The effectiveness of the correction of the disruptions of the cellular oxidative status with the peptide product of the pituitary gland was tested 30 days after the onset of the combined effect of stress factors on rats. It was found that the use of this bioactive peptide product in experimental animals exposed to different light modes and a chemical factor contributed to a decrease in the initially increased indicators of lipid peroxidation in rat erythrocytes and an increase in the initially reduced indicators of the enzymatic link of antioxidant protection. The activity of superoxide dismutase, glutathione peroxidase, glutathione transferase, as well as glucose-6-phosphate dehydrogenase increased after pharmacological correction. The concentration of reduced glutathione also increased in erythrocytes. The maximum changes were observed in the experimental subgroup of rats exposed to the combined effects of constant illumination and depriming toxicant. It was also found that the revealed positive changes in the indicators of the enzymatic link of antioxidant protection in animals of the experimental subgroups are associated with the maintenance of a sufficient concentration of reduced glutathione in red blood cells, which contributed to the maintenance of the cellular redox balance, when the conditions of the external lighting regime are violated.

Global metabolic regulation in Vibrio parahaemolyticus under polymyxin B stimulation

Vibrio parahaemolyticus is responsible for infection diseases of people who consume the contaminated seafood, but its metabolic regulation profile in response to colistin, the last treatment option for multidrug-resistant Gram-negative bacteria, remains unclear. In this study, the metabolic regulation profile of V. parahaemolyticus ATCC33846 under polymyxin B stimulation has been investigated. V. parahaemolyticus exposed to polymyxin B resulted in 4597 differentially transcribed genes, including 673 significantly up-regulated genes and 569 significantly down-regulated genes. In V. parahaemolyticus under polymyxin B stimulation, the cellular antioxidant systems to prevent bacteria from oxidant stress was activated, the synthesis of some nonessential macromolecules was reduced, and the assembly and modification of lipopolysaccharide and peptidoglycan to resist the attack from other antibiotics were promoted. These findings provide new insights into polymyxin B-related stress response in V. parahaemolyticus which should be useful for developing novel drugs for infection.

Selenium-Catalyzed Reduction of Hydroperoxides in Chemistry and Biology.

Among the chalcogens, selenium is the key element for catalyzed H2O2 reduction. In organic synthesis, catalytic amounts of organo mono- and di-selenides are largely used in different classes of oxidations, in which H2O2 alone is poorly efficient. Biological hydroperoxide metabolism is dominated by peroxidases and thioredoxin reductases, which balance hydroperoxide challenge and contribute to redox regulation. When their selenocysteine is replaced by cysteine, the cellular antioxidant defense system is impaired. Finally, classes of organoselenides have been synthesized with the aim of mimicking the biological strategy of glutathione peroxidases, but their therapeutic application has so far been limited. Moreover, their therapeutic use may be doubted, because H2O2 is not only toxic but also serves as an important messenger. Therefore, over-optimization of H2O2 reduction may lead to unexpected disturbances of metabolic regulation. Common to all these systems is the nucleophilic attack of selenium to one oxygen of the peroxide bond promoting its disruption. In this contribution, we revisit selected examples from chemistry and biology, and, by using results from accurate quantum mechanical modelling, we provide an accurate unified picture of selenium’s capacity of reducing hydroperoxides. There is clear evidence that the selenoenzymes remain superior in terms of catalytic efficiency.

Toxic effects of a mixture of five pharmaceutical drugs assessed using Fontinalis antipyretica Hedw.

The potential health risks associated with the pharmaceuticals released into the environment through effluents from sewage treatment plants have become a major cause for concern. Owing to the lack of effective indicators, monitoring the concentration of these pollutants in the aquatic environment is challenging. The aim of this study was to assess the toxicity of a mixture of five pharmaceutical drugs (paracetamol, carbamazepine, diclofenac, irbesartan, and naproxen) using the aquatic moss Fontinalis antipyretica as a bioindicator and bioaccumulator. We examined the effects of the drug mixture on the cellular antioxidant system, chlorophyll content, and morphological traits of F. antipyretica. The plant was exposed for 5 months to three concentrations of the mixture, including the environmental concentration (MX1), and 10- (MX10) and 100-times (MX100) the environmental concentration. The results showed that only carbamazepine and irbesartan were accumulated by the species. The bioconcentration level increased with exposure time, with the maximum uptake at the 4th month of exposure. The increase in bioaccumulation with exposure time was more evident in plants exposed to MX100. Analysis of the activity of antioxidant enzymes showed that superoxide dismutase (SOD, EC 1.15.1.1.) and catalase (EC 1.11.1.6.) were highly sensitive to the drug mixture. The activity of the enzymes was significantly higher in plants exposed to MX100; however, the activity of guaiacol peroxidase (GPX, EC 1.11.1.7.) was not significantly affected. Plants exposed to MX10 and MX100 had significantly lower total chlorophyll content and chlorophyll a/b ratio compared with those of plants in the control group; however, photosynthetic activity was restored after 5 months of exposure. The morphological characteristics of F. antipyretica were less sensitive to the treatment conditions.

Physicochemical Characteristics of Novel Cell-Bound Exopolysaccharide from Probiotic Limosilactobacillus fermentum (MTCC 5898) and Its Relation to Antioxidative Activity.

This study investigated the physicochemical characteristics and antioxidative role of novel acidic cell-bound exopolysaccharide (EPS-b) from probiotic Limosilactobacillus fermentum (MTCC 5898) and gained an insight into the structure-function relationship. The physicochemical analysis of EPS-b isolated by ultrasonication method revealed a heteropolysaccharide molecule with an average MW of 96.97 kDa composed of glucose and galactose subunits present in random-coiled conformation. Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) analyses further supported the observation and indicated the presence of α-(1 → 6) linkages. The analyses implicated the significant influence of structural features on the antioxidative activity of EPS-b by showing remarkable ABTS scavenging, reducing, and metal chelating potential with increasing concentration. Besides, the EPS-b by its scavenging potential also maintained the oxidative balance in the Caco-2 cells under oxidative stress and preserved the cellular antioxidative defense system (CAT, GPx, SOD, HO1, and GCLC) at the basal level.

Tingenone and 22-hydroxytingenone target oxidative stress through downregulation of thioredoxin, leading to DNA double-strand break and JNK/p38-mediated apoptosis in acute myeloid leukemia HL-60 cells

Acute myeloid leukemia (AML) is the most lethal form of leukemia. Standard anti-AML treatment remains almost unchanged for decades. Tingenone (TG) and 22-hydroxytingenone (22-HTG) are quinonemethide triterpenes found in the Amazonian plant Salacia impressifolia (Celastraceae), with cytotoxic properties in different histological types of cancer cells. In the present work, we investigated the anti-AML action mechanism of TG and 22-HTG in the AML HL-60 cell line. Both compounds exhibited potent cytotoxicity in a panel of cancer cell lines. Mechanistic studies found that TG and 22-HTG reduced cell growth and caused the externalization of phosphatidylserine, the fragmentation of internucleosomal DNA and the loss of mitochondrial transmembrane potential in HL-60 cells. In addition, pre-incubation with Z-VAD(OMe)-FMK, a pan-caspase inhibitor, prevented TG- and 22-HTG-induced apoptosis, indicating cell death by apoptosis via a caspase-dependent pathway. The analysis of the RNA transcripts of several genes indicated the interruption of the cellular antioxidant system, including the downregulation of thioredoxin, as a target for TG and 22-HTG. The application of N-acetyl-cysteine, an antioxidant, completely prevented apoptosis induced by TG and 22-HTG, indicating activation of the apoptosis pathway mediated by oxidative stress. Moreover, TG and 22-HTG induced DNA double-strand break and phosphorylation of JNK2 (T183/Y185) and p38α (T180/Y182), and co-incubation with SP 600125 (JNK/SAPK inhibitor) and PD 169316 (p38 MAPK inhibitor) partially prevented apoptosis induced by TG and 22-HTG. Together, these data indicate that TG and 22-HTG are new candidate for anti-AML therapy targeting thioredoxin.

Ferroptosis Regulation by Nutrient Signalling.

Tremendous progress has been made in the field of ferroptosis since this regulated cell death process was first named in 2012. Ferroptosis is initiated upon redox imbalance and driven by excessive phospholipid peroxidation. Levels of multiple intracellular nutrients (iron, selenium, vitamin E and coenzyme Q10) are intimately related to the cellular antioxidant system and participate in the regulation of ferroptosis. Dietary intake of monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) regulates ferroptosis by directly modifying the fatty acid composition in cell membranes. In addition, amino acids and glucose (energy stress) manipulate the ferroptosis pathway through the nutrient-sensitive kinases mechanistic target of rapamycin complex 1 (mTORC1) and AMP-activated protein kinase (AMPK). Understanding the molecular interaction between nutrient signals and ferroptosis sensors might help in the identification of the roles of ferroptosis in normal physiology and in the development of novel pharmacological targets for the treatment of ferroptosis-related diseases.

Tumor Microenvironment-Modulated Nanozymes for NIR-II-Triggered Hyperthermia-Enhanced Photo-Nanocatalytic Therapy via Disrupting ROS Homeostasis.

PurposeReactive oxygen species (ROS) are a group of signaling biomolecules that play important roles in the cell cycle. When intracellular ROS homeostasis is disrupted, it can induce cellular necrosis and apoptosis. It is desirable to effectively cascade-amplifying ROS generation and weaken antioxidant defense for disrupting ROS homeostasis in tumor microenvironment (TME), which has been recognized as a novel and ideal antitumor strategy. Multifunctional nanozymes are highly promising agents for ROS-mediated therapy.MethodsThis study constructed a novel theranostic nanoagent based on PEG@Cu2-xS@Ce6 nanozymes (PCCNs) through a facile one-step hydrothermal method. We systematically investigated the photodynamic therapy (PDT)/photothermal therapy (PTT) properties, catalytic therapy (CTT) and glutathione (GSH) depletion activities of PCCNs, antitumor efficacy induced by PCCNs in vitro and in vivo.ResultsPCCNs generate singlet oxygen (1O2) with laser (660 nm) irradiation and use catalytic reactions to produce hydroxyl radical (•OH). Moreover, PCCNs show the high photothermal performance under NIR II 1064-nm laser irradiation, which can enhance CTT/PDT efficiencies to increase ROS generation. The properties of O2 evolution and GSH consumption of PCCNs achieve hypoxia-relieved PDT and destroy cellular antioxidant defense system respectively. The excellent antitumor efficacy in 4T1 tumor-bearing mice of PCCNs is achieved through disrupting ROS homeostasis-involved therapy under the guidance of photothermal/photoacoustic imaging.ConclusionOur study provides a proof of concept of “all-in-one” nanozymes to eliminate tumors via disrupting ROS homeostasis.

Abstract 2021: Differential expression of antioxidant and detoxifying enzymes induced by e-cigarette aerosol

Abstract Background: Last decade, there has been an increasing interest in the use of electronic cigarette (e-cig) among the youths. E-cigs are promoted as a safer alternative to tobacco cigarettes, but the long term health effects of e-cigs are unknown. E-cig aerosols contain harmful and potentially harmful substances, i.e., nicotine, ultrafine particles, flavoring agents, carbonyl compound, heavy metals, and carcinogens. In addition to containing reactive oxygen species (ROS), e-cig aerosols can also increase the cellular ROS production potentially leading to further alterations in the antioxidant system and its regulators. A recent in-vitro study from our laboratory showed that e-cigs aerosols can suppress the cellular antioxidant defenses and induced oxidative DNA damage in human epithelial cells. The effects of e-cig aerosols on antioxidant and detoxifying enzymes and its regulators are unknown. Aims: To investigate whether exposure to EC aerosol extracts alters the expression of antioxidant and detoxifying enzymes in human epithelial cells. Methods: Human oral epithelial cancer (UM-SCC-1) and non-cancer (POE9n) cell lines were exposed every other day for 2 weeks to e-cig aerosol. E-cig aerosols were prepared from two distinct e-cig brands (18 mg/ml of nicotine; tobacco flavor). Standard tobacco extracts (mainstream smoke, MS) were used as positive control. Gene and protein expression were quantified by RT-PCR and Western blotting respectively. Data were analyzed by Student's t-test and ANOVA. Results: Exposure to e-cig aerosol, but not to MS smoke, led to a decrease in NRF2 and SOD2 mRNA expression in both cell lines. A significant decrease in protein expression was also observed for NRF2 protein after exposure to e-cig aerosol. A significant increase in CYP1B1 was observed after exposure to e-cig aerosol and MS smoke. Conclusion: E-cig aerosol exposure decreases the expression of NRF2 a major regulator of the antioxidant response. This might put the cell under additional oxidative stress which can have major biological implications. E-cig aerosol exposure increases the expression of CYP1B1, a protein with a key role in the bioactivation of tobacco pro-carcinogens and the regulation of the redox homeostasis. Overall, our study suggests that e-cig aerosol not only carries high levels of ROS, but also alters the cellular detoxification and antioxidant system leading to a higher oxidative stress status that would be anticipated. Grant support: This work was supported by the National Institutes of Health, National Cancer Institute (R01CA242168). Dr. Queimado holds a Presbyterian Health Foundation Endowed Chair in Otorhinolaryngology, Oklahoma Tobacco Research Center (LQ). Citation Format: Vengatesh Ganapathy, Jimmy Manyanga, Lurdes Queimado. Differential expression of antioxidant and detoxifying enzymes induced by e-cigarette aerosol [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2021.

Chlorogenic Acid Ameliorates Damage Induced by Fluorene-9-Bisphenol in Porcine Sertoli Cells.

4,4′-(9-Fluorenylidene) diphenol (BPFL, also known as BHPF and fluorene-9-bisphenol) is a novel bisphenol A substitute that is used in the plastics industry as an organic synthesis intermediate and is a potential endocrine disruptor. However, the deleterious effects of BPFL on porcine Sertoli cells (SCs) and the possible underlying mechanisms are still unclear. Chlorogenic acid (CA) is a free radical scavenger in the cellular antioxidant system that prevents oxidative damage and apoptosis. In the present research, we found that BPFL induced impairments in porcine SCs in a dose-dependent manner and that CA protected porcine SCs against BPFL exposure-induced impairments. Cell viability, proliferation and apoptosis assay results revealed that BPFL exposure could inhibit porcine SC proliferation and induce apoptosis, while CA supplementation ameliorated the effects of BPFL. Further analysis revealed that BPFL exposure induced oxidative stress, mitochondrial membrane potential dysfunction and DNA damage accumulation. Transcriptome analysis and further real-time quantitative PCR and Western blot results showed that BPFL exposure induced endoplasmic reticulum stress and apoptosis. Supplementation with CA dramatically ameliorated these phenotypes in BPFL-exposed porcine SCs. Overall, the present research reveals the possible underlying mechanisms by which BPFL exposure induced impairments and CA supplementation protected against these impairments in porcine SCs.

Promising Green Technology in Obtaining Functional Plant Preparations: Combined Enzyme-Assisted Supercritical Fluid Extraction of Flavonoids Isolation from Medicago Sativa Leaves.

To elaborate a complete extraction protocol for the enhanced release of biologically active compounds from plant cells, this study aimed to optimize together the parameters of the supercritical fluid extraction (SFE) process (temperature, pressure, and percentage of cosolvent) and enzymatic treatment of plant material (pH, enzyme concentration, time, and temperature) by response surface methodology (RSM). Medicago sativa L. was selected as a plant material due to its richness in phenolics and flavonoids. HPLC-MS/MS analysis allowed evaluating the content of individual bioactive compounds in obtained extracts. The total content of polyphenolic compounds in the extract obtained after two-step optimization was much higher (546 ± 21 µg/g) than in the extract obtained from non-hydrolyzed material (275 ± 23 µg/g) and in the extract obtained by maceration (162 ± 20 µg/g). Furthermore, it was evidenced that extract with the highest content of polyphenolic compounds can support the cellular antioxidant system both as a free radical scavenger and by stimulating the antioxidant enzyme system.

Modulating skin colour: role of the thioredoxin and glutathione systems in regulating melanogenesis.

Different skin colour among individuals is determined by the varying amount and types of melanin pigment. Melanin is produced in melanocytes, a type of dendritic cell located in the basal layer of the epidermis, through the process of melanogenesis. Melanogenesis consists of a series of biochemical and enzymatic reactions catalysed by tyrosinase and other tyrosinase-related proteins, leading to the formation of two types of melanin, eumelanin and pheomelanin. Melanogenesis can be regulated intrinsically by several signalling pathways, including the cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA), stem cell factor (SCF)/c-kit and wingless-related integration site (Wnt)/β-catenin signalling pathways. Ultraviolet radiation (UVR) is the major extrinsic factor in the regulation of melanogenesis, through the generation of reactive oxygen species (ROS). Antioxidants or antioxidant systems, with the ability to scavenge ROS, may decrease melanogenesis. This review focuses on the two main cellular antioxidant systems, the thioredoxin (Trx) and glutathione (GSH) systems, and discusses their roles in melanogenesis. In the Trx system, high levels/activities of thioredoxin reductase (TrxR) are correlated with melanin formation. The GSH system is linked with regulating pheomelanin formation. Exogenous addition of GSH has been shown to act as a depigmenting agent, suggesting that other antioxidants may also have the potential to act as depigmenting agents for the treatment of human hyperpigmentation disorders.

A carrier-free metal-coordinated dual-photosensitizers nanotheranostic with glutathione-depletion for fluorescence/photoacoustic imaging-guided tumor phototherapy

As a promising noninvasive tumor treatment modality, dual phototherapy, including photodynamic therapy (PDT) and photothermal therapy (PTT), has drawn extensive research interest in imaging-guided synergistic antitumor treatment. However, developing a high-efficient phototherapeutic agent is still a huge challenge, since single photosensitizer often suffers from the insufficient photothermal conversion efficiency (PCE) or low reactive oxygen species (ROS) productivity. Moreover, the overexpression of reductive glutathione (GSH) in tumor cells also severely compromises PDT efficiency. Here, inspired by the glutathione oxidase activity of high-valent transition metal ions, we designed a copper-coordinated nanotheranostic (PhA@NanoICG) by the coordination-driven co-assembly of photothermal-agent indocyanine green (ICG) and photodynamic-agent pheophorbide A (PhA), in which Cu2+ acted as a bridge to tightly associate ICG with PhA. Such carrier-free metal-coordinated nanotheranostics exhibited ultra-high dual-photosensitizers co-loading (~96.74 wt%) and excellent structural stability. Notably, NanoICG significantly increase the PCE of ICG via J-aggregation induced UV–vis absorption red-shift. Once PhA@NanoICG accumulated in tumor sites, they could be disassembled triggered by the weakly acidic and highly reducible tumor microenvironment. Moreover, the Cu2+ can deplete intracellular GSH and impair cellular antioxidant defense system, reducing the unnecessary ROS consumption caused by glutathione. Under fluorescence/photoacoustic imaging-guided laser irradiation, local hyperthermia and ROS were generated to induce tumor cells apoptosis. The in vitro and in vivo experiments consistently confirm that PhA@NanoICG could induce remarkable tumor inhibition through self-enhanced PTT and PDT, which may pave a new way for cancer therapy.