Hydrogen peroxide-induced oxidative stress and its impact on innate immune responses in lung carcinoma A549 cells

Integrating gene expression and splicing dynamics across dose-response oxidative modulators

Toxicological risk assessment increasingly utilizes transcriptomics to derive point of departure (POD) and modes of action (MOA) for chemicals. One essential biological process that allows a single gene to generate several different RNA isoforms is called alternative splicing. To comprehensively assess the role of splicing dysregulation in toxicological evaluation and elucidate its potential as a complementary endpoint, we performed RNA-seq on A549 cells treated with five oxidative stress modulators across a wide dose range. Differential gene expression (DGE) showed limited pathway enrichment except at high concentrations. However, alternative splicing analysis revealed variable intron retention events affecting diverse pathways for all chemicals in the absence of significant expression changes. For instance, diazinon elicited negligible gene expression changes but progressive increase in the number of intron retention events, suggesting splicing alterations precede expression responses. Benchmark dose modeling of intron retention data highlighted relevant pathways overlooked by expression analysis. Systematic integration of splicing datasets should be a useful addition to the toxicogenomic toolkit. Combining both modalities paint a more complete picture of transcriptomic dose-responses. Overall, evaluating intron retention dynamics afforded by toxicogenomics may provide biomarkers that can enhance chemical risk assessment and regulatory decision making. This work highlights splicing-aware toxicogenomics as a possible additional tool for examining cellular responses.

Correlative study on heavy metal-induced oxidative stress and hypertension among the rural population of Malwa Region of Punjab, India

Heavy metal-induced toxicity contributes to the progression of various metabolic disorders and possible mechanisms involved in disease progression are not well established. In this study, the correlation of  heavy metal exposure and  hypertension have been demonstrated. The results showed that in hypertensive subjects, the lipid profiles (triglycerides, LDL-C, HDL-C, and total cholesterol) and cardiac markers (CK-MB and LDH) were altered abruptly. As a consequence of heavy- induced oxidative stress, the oxidants (TBARS and protein carbonyls) and antioxidants (SOD, GSH, and TAC) were significantly increased and decreased, respectively in hypertension subjects. The concentrations of heavy metals (Pb, Cd, and As) exceeded the permissible limits in hypertensive subjects. The Nrf-2 genotyping indicated that heavy metals may induce mutations at molecular level. The results of correlation analysis revealed that the heavy metals interact with cellular components and interfere with metabolic processes which then results in disturbed lipid profile, enhanced oxidative stress, and reduced antioxidant status. The current study systematically estimated the association of hair and nail heavy metal concentrations with hypertension among the population residing in the Malwa region of Punjab. The proposed study highlighted that heavy metals act as a silent risk factor in the hypertension progression in the population of Malwa region. Future studies are required to confirm current findings and further scrutinize the effect of heavy metals exposure in early adulthood, early, and late mid-life to develop metabolic complications such as hypertension.

Administration of N-Acetylcysteine to Regress the Fibrogenic and Proinflammatory Effects of Oxidative Stress in Hypertrophic Ligamentum Flavum Cells

Ligamentum flavum hypertrophy (LFH) is a major cause of lumbar spinal stenosis (LSS). In hypertrophic ligamentum flavum (LF) cells, oxidative stress activates intracellular signaling and induces the expression of inflammatory and fibrotic markers. This study explored whether healthy and hypertrophic LF cells respond differently to oxidative stress, via examining the levels of phosphorylated p38 (p-p38), inducible nitric oxide synthase (iNOS), and α-smooth muscle actin (α-SMA). Furthermore, the efficacy of N-acetylcysteine (NAC), an antioxidant, in reversing the fibrogenic and proinflammatory effects of oxidative stress in hypertrophic LF cells was investigated by assessing the expression levels of p-p38, p-p65, iNOS, TGF-β, α-SMA, vimentin, and collagen I under H2O2 treatment with or without NAC. Under oxidative stress, p-p38 increased significantly in both hypertrophic and healthy LF cells, and iNOS was elevated in only the hypertrophic LF cells. This revealed that oxidative stress negatively affected both hypertrophic and healthy LF cells, with the hypertrophic LF cells exhibiting more active inflammation than did the healthy cells. After H2O2 treatment, p-p38, p-p65, iNOS, TGF-β, vimentin, and collagen I increased significantly, and NAC administration reversed the effects of oxidative stress. These results can form the basis of a novel therapeutic treatment for LFH using antioxidants.

Accidental lead in contaminated pipe-borne water and dietary furan intake perturbs rats' hepatorenal function altering oxidative, inflammatory, and apoptotic balance

Inadvertent exposure to furan and Pb is associated with hepatorenal abnormalities in humans and animals. It is perceived that these two chemical species may work in synergy to orchestrate liver and kidney damage. Against this background, we investigated the combined effect of furan and incremental lead (Pb) exposure on hepatorenal dysfunction. Wistar rats (n = 30; 150 g) were treated for 28 days accordingly: Control; FUR (8 mg/kg), PbAc (100 µg/L), FUR + PbAc₁ (8 mg/kg FUR + 1 µg/L PbAc); FUR + PbAc₁ (8 mg/kg FUR + 10 µg/L PbAc), and FUR + PbAc₁ (8 mg/kg FUR + 100 µg/L PbAc). Biomarkers of hepatorenal function, oxidative stress, inflammation, DNA damage, and apoptosis were examined. Furan and incrementally Pb exposure increased the levels of hepatorenal biomarkers and oxidative and pro-inflammatory mediators, including lipid peroxidation, reactive oxygen and nitrogen species, and interleukin-1 beta. Increased DNA damage, caspases- 9 and -3, and atypical histoarchitecture of the hepatorenal tissues exemplified furan and Pb treatment-related perturbations. Furthermore, the levels of antioxidants and IL-10 were also suppressed. Furan and Pb dose-dependently exacerbated hepatorenal derangements by altering the redox and inflammatory rheostats, worsened DNA damage, and related apoptotic onset that may potentiate hepatorenal disorders in humans and animals. The findings validate the synergistic effect of furan and Pb in the pathophysiology of kidney and liver disorders.

Investigating the effect of Sulforaphane on AMPK/AKT/NRF2 pathway in human granulosa-lutein cells under H2O2-induced oxidative stress

Excessive production of reactive oxygen species (ROS) in granulosa cells (GCs) plays a role in pathogenesis of polycystic ovarian syndrome (PCOS) by developing oxidative stress (OS). It was shown that Sulforaphane (SFN), with known antioxidant properties, can have protective effects in different diseases through affecting the nuclear factor (erythroid-derived 2)-like 2 (NRF2) signaling pathway. Thus, the purpose of the current work was to examine the protective impact of SFN through the activation of the AMPK/AKT/NRF2 pathway against OS produced by H2O2 in granulosa-lutein cells (GLCs). Individuals' GLCs were obtained during ovum retrieval in intracytoplasmic sperm injection (ICSI) cycles. First, the induced OS model was created in GLCs using H₂O₂ exposure. To examine the protective effect of SFN against OS, the cells were cultured for 24 h in presence or absence of SFN. Eventually, the levels of intracellular ROS and apoptosis were measured by flow cytometry, and genes and proteins expression levels of AMPK, AKT, and NRF2 were evaluated using qRT-PCR and western blotting. Compared to the control group, the levels of intracellular ROS and apoptosis rose dramatically in GLCs with enhanced OS. SFN therapy decreased ROS and apoptosis levels and increased the overexpression of AMPK, AKT, and NRF2 genes and proteins. This study's results revealed that SFN exposure results in the alleviation of ROS and apoptosis levels possibly through activating the overexpression of genes and proteins of AMPK, AKT, and NRF2, and exerts its protective effects against OS in GLCs.

Low dose epigallocatechin-3-gallate revives doxorubicin responsiveness by a redox-sensitive pathway in A549 lung adenocarcinoma cells

Pulmonary cancer confronts the greatest hurdle of resistance against most chemotherapeutic drugs. This may be circumvented with a combination of conventional chemotherapy with bioactive herbal adjuvant. Epigallocatechin-3-gallate (EGCG), was investigated for its chemo-sensitizing property along with doxorubicin (Dox), in an intrinsically nonresponsive lung adenocarcinoma (LAC) cell line, A549. A compromised functionality of Dox was reversed when EGCG was used as an adjuvant. On one hand, Dox (10 μM)-EGCG (0.5 μM) post treatment combination decreased the drug efflux, multidrug-resistance (MDR) signaling, invasiveness while, on the other hand, it increased drug internalization, cell-cycle arrest, stress-induced damage, and finally cell death. The resistant nature of A549 was probably due to constitutive activation of nuclear erythroid 2-related factor 2 (Nrf2) and its upstream/downstream antioxidant effectors, which were also pro-oxidatively coordinated by EGCG. In conclusion low dose EGCG improved Dox-toxicity and imparted oxidative damage-mediated antineoplastic efficacy by reorienting the redox signaling in A549 LAC cells.

Toxicity impact of hydrogen peroxide on the fate of zebrafish and antibiotic resistant bacteria

Hydrogen peroxide (H₂O₂) is applied in various environments. It could be present at concentrations ranging from nanomolar to micromolar in a water system. It is produced through pollutants and natural activities. Since few studies have been conducted about the impact of naturally produced H₂O₂ on aquatic organisms, the objective of the present study was to monitor changes in responses of aquatic model organisms such as zebrafish and antibiotic-resistant bacteria to different exogenous H₂O₂ exposure. Increases in exposure concentration and time induced decreases in the perception of zebrafish larvae (up to 69%) and movement of adult zebrafish (average speed, average acceleration, movement distance, and activity time) compared to the control (non-exposed group). In addition, as a function of H₂O₂ exposure concentration (0-100,000 nM) and time, up to 20-fold increase (p = 5.00*10^-6) of lipid peroxidation compared to control was observed. For microorganisms, biofilm, an indirect indicator of resistance to external stressors, was increased up to 68% and gene transfer was increased (p = 2.00*10^-6) by more than 30% after H₂O₂ exposure. These results imply that naturally generated H₂O₂ could adversely affect aquatic environment organisms and public health. Thus, more careful attention is needed for H₂O₂ production in an aquatic system.

Effect of a Combination of Rosa canina Fruits and Apple Cider Vinegar against Hydrogen Peroxide-Induced Toxicity in Experimental Animal Models

Oxidative stress is the trigger of several diseases. It is an imbalance between the production of free radicals and antioxidants. This study aims to evaluate the antioxidant capacity and the protective property of Rosa canina fruits and apple cider vinegar combined or not against hydrogen peroxide (H2O2)-induced toxicity in Wistar rats. The experiment included five groups: group 1 received distilled water (10 mL/kg b.wt), group 2 received H2O2 10% (10 mL/kg b.wt), group 3 received H2O2 10% (10 mL/kg b.wt) and apple vinegar (2 mL/kg b.wt); group 4 received H2O2 10% (10 mL/kg b.wt) and apple vinegar supplemented with Rosa canina fruits extract (300 mg/kg b.wt); group 5 received H2O2 10% (10 mL/kg b.wt) and extract of Rosa canina fruits (300 mg/kg b.wt). The doses were given once daily via a gavage. The antioxidant capacity of apple vinegar and Rosa canina extract was analyzed, and AST, ALT, PAL, urea, and creatinine were determined on day 22 of the experiment. In addition, the kidney and the liver tissues were analyzed. The results showed that H2O2 caused a significant elevation of blood urea, blood creatinine, and transaminases. The histopathology examination revealed that H2O2 caused congestion, hemorrhage, and Bowman’s space enlarged. On the other hand, the results clearly showed that apple vinegar and Rosa canina fruits counterbalance the biochemical and histological changes induced by H2O2. In conclusion, the two natural products studied in this work are effective against the harmful effect of oxidative stress, which explains their use in traditional medicine.

Erythrocyte Fraction in Thrombi Is Increased with Serum Iron by Influencing Fibrin Networks via Oxidative Stress

Objective

This study investigated whether the erythrocyte fraction in thrombi would be increased with serum iron via oxidative stress.

Methods

This study retrospectively enrolled patients with acute ischemic stroke treated using endovascular treatment in a single stroke center from October to December 2019. We examined the relationship between serum iron and erythrocyte-rich thrombi and the correlation of serum iron and the erythrocyte fraction in thrombi using clinical samples. Experiments in vivo and in vitro were performed to investigate the influence of oxidative stress on the correlation between serum iron concentration and erythrocyte fraction in thrombi.

Results

We found from the clinical samples that serum iron concentration was related to erythrocyte-rich thrombi and positively associated with the erythrocyte fraction in thrombi in vivo. Further, the tightness of the fibrin networks regulating the erythrocyte fraction in thrombi was increased with serum iron concentration in vivo. Additionally, the oxidative stress level was increased with serum iron concentration in vivo. Moreover, we found that the tightness of the fibrin networks increased with higher oxidative stress levels in vitro. Lastly, experiments in vivo with inhibiting oxidative stress showed that the erythrocyte fraction in thrombi and the tightness of fibrin networks significantly increased in the iron group than those in the iron with oxidative stress inhibitor group and control group.

Conclusions

Oxidative stress played a role in the process that the erythrocyte fraction in thrombi was increased with serum iron by influencing fibrin networks.

The Protective Effect of Sulforaphane against Oxidative Stress through Activation of NRF2/ARE Pathway in Human Granulosa Cells

Objective

Sulforaphane (SFN) is a natural free radical scavenger that can reduce oxidative stress (OS) through mediating nuclear factor (erythroid-derived 2)-like 2 (NF-E2-related factor 2 or NRF2)/antioxidant response element (ARE) signaling pathway and the downstream antioxidant enzymes. Here, we intended to study the role of SFN in OS- induced human granulosa cells (GCs) by investigating the intracellular levels of reactive oxygen species (ROS), cell death, and NRF2-ARE pathway.

Materials and Methods

This experimental study was conducted on GCs of 12 healthy women who had normal menstrual cycles with no history of polycystic ovary syndrome (PCOS), endometriosis, menstrual disorders, hyperprolactinemia, or hormonal therapy. After isolation of GCs, the MTT assay was performed to explore GCs viability after treatment with SFN in the presence or absence of H2O2. Flow cytometry was utilized to determine the intracellular ROS production and the apoptosis rate. Evaluation of the mRNA and protein expression levels of NRF2 and phase II enzymes including superoxide dismutase (SOD) and catalase (CAT) was performed by quantitative real-time polymerase chain reaction (PCR) and western blotting. Finally, the data were analyzed by SPSS software using One-way ANOVA and the suitable post-hoc test. Significance level was considered as P<0.05.

Results

Pretreatment of GCs with SFN attenuated intracellular ROS production and apoptosis rate in the H₂O₂-exposed cells. Moreover, SFN treatment increased the mRNA expression level of NRF2, SOD, and CAT. Higher expression of NRF2 and SOD was also observed at the protein level.

Conclusion

Our study demonstrated that SFN protects human GCs against H2O2induced-OS by reducing the intracellular ROS production and the following apoptosis through a mechanism by which NRF2 increases the antioxidant enzymes such as SOD and CAT. This result may have a potential application in assisted reproduction cycles by improving the quality of GCs and the embedded oocyte, especially in PCOS patients.

The migration behavior of human glioblastoma cells is influenced by the redox-sensitive human macrophage capping protein CAPG

The macrophage capping protein CAPG belongs to the gelsolin superfamily which modulates actin dynamics by capping the growing end of actin filaments in a Ca²⁺- and PIP₂-dependent manner resulting in polymerization inhibition of actin filaments. In the last years, additional functions for CAPG in transcription regulation were described and higher CAPG amounts have been linked to increased invasiveness and migration behavior in different human tumor entities like e.g. glioblastoma. Nevertheless, there is a lack of knowledge how additional functions of CAPG are regulated. As CAPG contains several cysteine residues which may be accessible to oxidation we were especially interested to investigate how alterations in the cysteine oxidation state may influence the function, localization, and regulation of CAPG. In the present study, we provide strong evidence that CAPG is a redox-sensitive protein and identified two cysteines: C282 and C290 as reversibly oxidized in glioblastoma cell lines. Whereas no evidence could be found that the canonical actin capping function of CAPG is redox-regulated, our results point to a novel role of the identified cysteines in the regulation of cell migration. Along with this, we found a localization shift out of the nucleus of CAPG and RAVER1, a potential interaction partner identified in our study which might explain the observed altered cell migration properties. The newly identified redox sensitive cysteines of CAPG could perspectively be considered as new targets for controlling tumor invasive properties.

Hypoxia, oxidative stress, and immune evasion: a trinity of the trichothecenes T-2 toxin and deoxynivalenol (DON)

T-2 toxin and deoxynivalenol (DON) are type A and B trichothecenes, respectively. They widely occur as pollutants in food and crops and cause a series of toxicities, including immunotoxicity, hepatotoxicity, and neurotoxicity. Oxidative stress is the primary mechanistic basis of these toxic effects. Increasing amounts of evidence have shown that mitochondria are significant targets of apoptosis caused by T-2 toxin- and DON-induced oxidative stress via regulation of Bax/B-cell lymphoma-2 and caspase-3/caspase-9 signaling. DNA methylation and autophagy are involved in oxidative stress related to apoptosis, and hypoxia and immune evasion are related to oxidative stress in this context. Hypoxia induces oxidative stress by stimulating mitochondrial reactive oxygen species production and regulates the expression of cytokines, such as interleukin-1β and tumor necrosis factor-α. Programmed cell death-ligand 1 is upregulated by these cytokines and by hypoxia-inducible factor-1, which allows it to bind to programmed cell death-1 to enable escape of immune cell surveillance and achievement of immune evasion. This review concentrates on novel findings regarding the oxidative stress mechanisms of the trichothecenes T-2 toxin and DON. Importantly, we discuss the new evidence regarding the connection of hypoxia and immune evasion with oxidative stress in this context. Finally, the trinity of hypoxia, oxidative stress and immune evasion is highlighted. This work will be conducive to an improved understanding of the oxidative stress caused by trichothecene mycotoxins.

Antioxidant Effects of Turmeric Leaf Extract against Hydrogen Peroxide-Induced Oxidative Stress In Vitro in Vero Cells and In Vivo in Zebrafish

Oxidative stress, caused by the excessive production of reactive oxygen species (ROS), results in cellular damage. Therefore, functional materials with antioxidant properties are necessary to maintain redox balance. Turmeric leaves (Curcuma longa L. leaves; TL) are known to have antioxidant properties, including 2,2-Diphenyl-1-picrylhydrazyl (DPPH), 2,2′-Azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS), and Hydrogen peroxide (H₂O₂) radical scavenging activity in several studies. The antioxidant effects of TL come from distinct bioactive compounds, such as curcumin, total phenolic compounds, and flavonoids. Therefore, in this study, the antioxidant effects of a water extract of TL (TLE) against H₂O₂ treatment were assessed in vitro Vero cells and in vivo zebrafish models. The intracellular ROS generation and the proportion of sub-G1 phase cells were evaluated in H₂O₂- or/and TLE-treated Vero cells to measure the antioxidant activity of TLE. TLE showed outstanding intracellular ROS scavenging activity and significantly decreased the proportion of cells in the sub-G1 phase in a dose-dependent manner. Furthermore, cell death, ROS generation, and lipid peroxidation in the H₂O₂-treated zebrafish model were attenuated as a consequence of TLE treatment. Collectively, the results from this study suggested that TLE may be an alternative material to relieve ROS generation through its antioxidant properties or a suitable material for the application in a functional food industry.

Ascorbate-induced oxidative stress mediates TRP channel activation and cytotoxicity in human etoposide-sensitive and -resistant retinoblastoma cells

There are indications that pharmacological doses of ascorbate (Asc) used as an adjuvant improve the chemotherapeutic management of cancer. This favorable outcome stems from its cytotoxic effects due to prooxidative mechanisms. Since regulation of intracellular Ca2+ levels contributes to the maintenance of cell viability, we hypothesized that one of the effects of Asc includes disrupting regulation of intracellular Ca2+ homeostasis. Accordingly, we determined if Asc induced intracellular Ca2+ influx through activation of pertussis sensitive Gi/o-coupled GPCR which in turn activated transient receptor potential (TRP) channels in both etoposide-resistant and -sensitive retinoblastoma (WERI-Rb1) tumor cells. Ca2+ imaging, whole-cell patch-clamping, and quantitative real-time PCR (qRT-PCR) were performed in parallel with measurements of RB cell survival using Trypan Blue cell dye exclusion. TRPM7 gene expression levels were similar in both cell lines whereas TRPV1, TRPM2, TRPA1, TRPC5, TRPV4, and TRPM8 gene expression levels were downregulated in the etoposide-resistant WERI-Rb1 cells. In the presence of extracellular Ca2+, 1 mM Asc induced larger intracellular Ca2+ transients in the etoposide-resistant WERI-Rb1 than in their etoposide-sensitive counterpart. With either 100 µM CPZ, 500 µM La3+, 10 mM NAC, or 100 µM 2-APB, these Ca2+ transients were markedly diminished. These inhibitors also had corresponding inhibitory effects on Asc-induced rises in whole-cell currents. Pertussis toxin (PTX) preincubation blocked rises in Ca2+ influx. Microscopic analyses showed that after 4 days of exposure to 1 mM Asc cell viability fell by nearly 100% in both RB cell lines. Taken together, one of the effects underlying oxidative mediated Asc-induced WERI-Rb1 cytotoxicity stems from its promotion of Gi/o coupled GPCR mediated increases in intracellular Ca2+ influx through TRP channels. Therefore, designing drugs targeting TRP channel modulation may be a viable approach to increase the efficacy of chemotherapeutic treatment of RB. Furthermore, Asc may be indicated as a possible supportive agent in anti-cancer therapies.

Oxidative stress mediates age-related hypertrophy of ligamentum flavum by inducing inflammation, fibrosis, and apoptosis through activating Akt and MAPK pathways

The role of oxidative stress in ligamentum flavum (LF) hypertrophy has not been elucidated. We hypothesize that oxidative stress induces inflammatory responses and the subsequent fibrotic processes in LF, via activation of the Akt and MAPK pathways. Specimens of LFs were collected during surgeries for lumbar disc herniation (LDH) or lumbar spinal stenosis (LSS). Part of the LF specimens underwent analyses for ROS, fibrotic markers, and inflammatory mediators, with the remainder minced for cell cultures. The cell cultures were treated with H₂O₂, after which the cells were lysed and analyzed via western blotting. The specimens of the LSS patients showed increased infiltration of inflammatory cells and were stained positively for MMP-3, MMP-9, vimentin, and fibronectin. The LF of the LSS patients had increased oxidative stress and inflammation compared to that of the LDH patients. In vitro analyses demonstrated that oxidative stress rapidly activated the Akt and MAPK pathways. Inflammatory mediators, iNOS and NF-κB, and fibrotic markers, including TGF-β, β-catenin, α-SMA and vimentin, were significantly upregulated after induction of oxidative stress. Oxidative stress activated the intrinsic apoptotic pathway. These findings revealed that oxidative stress is one of the etiological factors of LF hypertrophy, which might provide new insights into treatment approaches.

Parthenium hysterophorus mediated inflammation and hyper-responsiveness via NF-κB pathway in human A549 lung cancer cell line

Being one of the notorious weed P. hysterophorus has invaded almost every part India and is the lead cause of skin allergies and severe dermatitis among farmers and rural population. It is an invasive obnoxious weed capable of surviving extreme environmental conditions and various parts of this plant are reported to cause severe contact allergies in humans due to the presence of high concentrations of toxic sesquiterpene lactones viz. parthenin. It can stimulate numerous cellular and immune responses that may translate into Oxidative stress, allergies, and inflammation. The effect of P. hysterophorus flower extract was evaluated on cell viability, oxidative stress and inflammation in A549 lung cancer cell line by spectrophotometric and reverse transcriptase-polymerase chain reaction methods. Schrodinger software based docking was performed for possible interactions studies. The A549 cells treated with P. hysterophorus flower extract favors increase in cell viability, reactive oxygen species generation. The mRNA expression of proinflammatory cytokines such as IFN-γ, TNF-α, and IL-1β was significantly increased whereas no change in IL-18 expression was observed. Significant increase in protein expression of NF-κB was observed, suggesting the role of NF-κB signalling in allergic responses. The docking studies demonstrated the potential interaction between Parthenin and NF-κB/IL-1β/IL-18 suggesting their activation leading to inflammation. The current study emphasize that P. hysterophorus mediates oxidative stress, and inflammatory process via alterations in expression of proinflammatory cytokines such as IL-1β, IFN-γ through NF-κB activation which was also confirmed in docking studies. Cellular and molecular mechanisms involved in pathogenesis of allergic/chronic inflammation and severe dermatitis need to be further investigated to identify specific binding partners responsible for severe inflammation which can provide some leads in developing effective targets against severe dermatitis and skin allergies.

Determination of antioxidant capacity of medicinal tinctures using cuprac method involving Cu(II) neocuproine immobilized into polymethacrylate matrix

This work suggests using Cu(II) - neocuproine redox system immobilized into transparent polymethacrylate matrix for assessment of antioxidant capacity using CUPRAC method. The method we developed makes it possible to quantify the content of the antioxidants in the concentration range of 5.9 × 10^-8-9.1 × 10^-5 M. The sensor was tolerant to pH variations and painting, and used for the antioxidant capacity determination values of some commercial medicinal tinctures without pretreatment.

Plasmonic active film integrating gold/silver nanostructures for H2O2 readout

A nanostructured Ag/Au adhesive film for H₂O₂ reagentless determination is here proposed. The film has been realised onto ELISA polystyrene microplates. Microwells surface has been initially modified with a gold nanoparticles (AuNPs)/polydopamine thin-film. The pristine AuNPs-decorated film was later functionalized with catechin (Au-CT) allowing a uniform formation of a plasmonic active nanostructured silver network in presence of Ag⁺. Changes in localized surface plasmon resonance (LSPR) of the silver network upon addition of H₂O₂ has been used as analytical signal, taking advantage of the etching phenomenon. The Ag/Au nanocomposite-film is characterized by a well-defined (LSPR_max = 405 ± 5 nm), reproducible (intraplate RSD ≤ 9.8%, n = 96; inter-plate RSD ≤ 11.4%, n = 480) and stable LSPR signal. The film's analytical features have been tested for H₂O₂ and glucose (bio)sensing. Satisfactory analytical performances were obtained both for H₂O₂ (linear range 1-200 μM, R² = 0.9992, RSD ≤ 6.3%, LOD = 0.2 μM) and glucose (linear range 2-250 μM, R² = 0.9998, RSD ≤ 8.9%, LOD = 0.4 μM). As proof of applicability, the determination of the two analytes in soft drinks has been carried out achieving good and reproducible recoveries (84-111%; RSD ≤ 9%). The developed nanostructured film overcomes analytical drawbacks associated with the use of colloidal dispersions in plasmonic assays carried out in solution; the low cost, robustness, ease of use and possibility of coupling enzymatic reactions appears very promising for (bio)sensors based on the detection of H₂O₂.

Glycyrrhiza glabra (Licorice) root extract attenuates doxorubicin-induced cardiotoxicity via alleviating oxidative stress and stabilising the cardiac health in H9c2 cardiomyocytes

ETHNOPHARMACOLOGICAL RELEVANCE

Doxorubicin (DOX) is an effective anti-neoplastic drug, however; it has downside effects on cardiac health and other vital organs. The herbal remedies used in day to day life may have a beneficial effect without disturbing the health of the vital organs. Glycyrrhiza glabra L. is a ligneous perennial shrub belonging to Leguminosae/Fabaceae/Papilionaceae family growing in Mediterranean region and Asia and widespread in Turkey, Italy, Spain, Russia, Syria, Iran, China, India and Israel. Commonly known as mulaithi in north India, G. glabra has glycyrrhizin, glycyrrhetic acid, isoliquiritin, isoflavones, etc., which have been reported for several pharmacological activities such as anti-demulcent, anti-ulcer, anti-cancer, anti-inflammatory and anti-diabetic.

AIM OF THE STUDY

The objective of the present study is to investigate the interaction between the molecular factors like PPAR-α/γ and SIRT-1 during cardiac failure arbitrated by DOX under in vitro conditions and role of Glycyrrhiza glabra (Gg) root extract in alleviating these affects.

MATERIALS AND METHODS

In the present study, we have examined the DOX induced responses in H9c2 cardiomyocytes and investigated the role of phytochemical Glycyrrhiza glabra in modulating these affects. MTT assay was done to evaluate the cell viability, Reactive Oxygen Species (ROS)/Reactive Nitrogen Species (RNS) levels, mitochondrial ROS, mitochondrial membrane potential was estimated using fluorescent probes. The oxidative stress in terms of protein carbonylation, lipid peroxidation and DNA damage was detected via spectrophotometric methods and immune-fluorescence imaging. The cardiac markers and interaction between SIRT-1 and PPAR-α/γ was measured using Real-Time PCR, Western blotting and Co-immunoprecipitation based studies.

RESULTS

The Glycyrrhiza glabra (Gg) extracts maintained the membrane integrity and improved the lipid homeostasis and stabilized cytoskeletal element actin. Gg phytoextracts attenuated aggravated ROS level, repaired the antioxidant status and consequently, assisted in repairing the DNA damage and mitochondrial function. Further, the expression of hypertrophic markers in the DOX treated cardiomyocytes reconciled the expression factors both at the transcriptional and translational levels after Gg treatment. SIRT-1 mediated pathway and its downstream activator PPARs are significant in maintaining the cellular functions. It was observed that the Gg extract allows regaining the nuclear SIRT-1 and PPAR-γ level which was otherwise reduced with DOX treatment in H9c2 cardiomyocytes. The co-immunoprecipitation (Co-IP) documented that SIRT-1 interacts with PPAR-α in the untreated control H9c2 cardiomyocytes whereas DOX treatment interferes and diminishes this interaction however the Gg treatment maintains this interaction. Knocking down SIRT-1 also downregulated expression of PPAR-α and PPAR-γ in DOX treated cells and Gg treatment was able to enhance the expression of PPAR-α and PPAR-γ in SIRT-1 knocked down cardiomyocytes.

CONCLUSIONS

The antioxidant property of Gg defend the cardiac cells against the DOX induced toxicity via; 1) reducing the oxidative stress, 2) maintaining the mitochondrial functions, 3) regulating lipid homeostasis and cardiac metabolism through SIRT-1 pathway, and 4) conserving the cardiac hypertrophy and hence preserving the cardiomyocytes health. Therefore, Gg can be recommended as a healthy supplement with DOX towards cancer therapeutics associated cardiotoxicity.

Comparison of the effect of chemically and biologically induced inflammation on the volatile metabolite production of lung epithelial cells by GC×GC-TOFMS

Exhaled breath analysis has a high potential for early non-invasive diagnosis of lung inflammatory diseases, such as asthma. The characterization and understanding of the inflammatory metabolic pathways involved into volatile organic compounds (VOCs) production could bring exhaled breath analysis into clinical practice and thus open new therapeutic routes for inflammatory diseases. In this study, lung inflammation was simulated in vitro using A549 epithelial cells. We compared the VOC production from A549 epithelial cells after a chemically induced oxidative stress in vitro, exposing the cells to H₂O₂, and a biological stress, exposing the cells to an inflammatory pool of sputum supernatants. Special attention was devoted to define proper negative and positive controls (8 different types) for our in vitro models, including healthy sputum co-culture. Sputum from 25 asthmatic and 8 healthy patients were collected to create each pool of supernatants. Each sample type was analyzed in 4 replicates using solid-phase microextraction (SPME) comprehensive two-dimensional gas chromatography hyphenated to time-of-flight mass spectrometry (GC×GC-TOFMS). This approach offers high resolving power for complex VOC mixtures. According to the type of inflammation induced, significantly different VOCs were produced by the epithelial cells compared to all controls. For both chemical and biological challenges, an increase of carbonyl compounds (54%) and hydrocarbons (31%) was observed. Interestingly, only the biological inflammation model showed a significant cell proliferation together with an increased VOC production linked to asthma airway inflammation. This study presents a complete GC×GC-TOFMS workflow for in vitro VOC analysis, and its potential to characterize complex lung inflammatory mechanisms.

Pyruvate secretion by oral streptococci modulates hydrogen peroxide dependent antagonism

Many commensal oral streptococci generate H₂O₂ via pyruvate oxidase (SpxB) to inhibit the growth of competing bacteria like Streptococcus mutans, a major cariogenic species. In Streptococcus sanguinis SK36 (SK36) and Streptococcus gordonii DL1 (DL1), spxB expression and H₂O₂ release are subject to carbon catabolite repression by the catabolite control protein A (CcpA). Surprisingly, ccpA deletion mutants of SK36 and DL1 fail to inhibit S. mutans despite their production of otherwise inhibitory levels of H₂O₂. Using H₂O₂-deficient spxB deletion mutants of SK36 and DL1, it was subsequently discovered that both strains confer protection in trans to other bacteria when H₂O₂ is added exogenously. This protective effect depends on the direct detoxification of H₂O₂ by the release of pyruvate. The pyruvate dependent protective effect is also present in other spxB-encoding streptococci, such as the pneumococcus, but is missing from spxB-negative species like S. mutans. Targeted and transposon-based mutagenesis revealed Nox (putative H₂O-forming NADH dehydrogenase) as an essential component required for pyruvate release and oxidative protection, while other genes such as sodA and dps play minor roles. Furthermore, pyruvate secretion is only detectable in aerobic growth conditions at biofilm-like cell densities and is responsive to CcpA-dependent catabolite control. This ability of spxB-encoding streptococci reveals a new facet of the competitive interactions between oral commensals and pathobionts and provides a mechanistic basis for the variable levels of inhibitory potential observed among H₂O₂-producing strains of commensal oral streptococci.

Synthesis of novel caffeic acid derivatives and their protective effect against hydrogen peroxide induced oxidative stress via Nrf2 pathway

AIM

This study was aimed to synthesize novel caffeic acid derivatives and evaluate their potential applications for the treatment of oxidative stress associated disease.

MAIN METHODS

Caffeic acid sulfonamide derivatives were synthesized by coupling sulfonamides to the backbone of caffeic acid and fully characterized by melting point test, FT-IR, MS, NMR, UV-vis and n-octanol-water distribution assay. Their free radical scavenging ability was evaluated using DPPH assay and cytotoxicity against A549 cells were determined by MTT assay. The protective effect of these derivatives against hydrogen peroxide (H₂O₂) induced oxidative injury was assessed in A549 cells from cell viability, production of reactive oxygen species (ROS) and malondialdehyde (MDA), alternation of antioxidase activities, and expressions of Nrf2 and its target genes.

KEY FINDINGS

Six novel caffeic acid sulfonamide derivatives were obtained. The derivatives showed better liphophilicity than the parent caffeic acid. CASMZ, CAST and CASQ exhibited similar DPPH scavenging capability as caffeic acid, while the protection of hydroxyl groups on the benzene ring with acetyl groups caused decrease in radical scavenging activity. No inhibitory effect on the proliferation of A549 cells were observed up to a concentration of 50 μM. Pre-treatment of cells with these derivatives strongly inhibited H₂O₂ induced decrease of cell viability, reduced the production of ROS and MDA, promoted antioxidase activities, and further upregulated the expression of Nrf2 and its target genes.

SIGNIFICANCE

Caffeic acid sulfonamide derivatives were synthesized with simple reactions under mild conditions. They might protect cells from H₂O₂-induced oxidative injury via Nrf2 pathway.