Production Of Reaction Oxygen Species Research Articles

Three-in-One: Molecular Engineering of D-A-π-A Featured Type I and Type II Near-Infrared AIE Photosensitizers for Efficient Photodynamic Cancer Therapy and Bacteria Killing.

Bacterial infections are closely correlated with the genesis and progression of cancer, and the elimination of cancer-related bacteria may improve the efficacy of cancer treatment. However, the combinatorial therapy that utilizes two or more chemodrugs will increase potential adverse effects. Image-guided photodynamic therapy is a highly precise and potential therapy to treat tumor and microbial infections. Herein, four donor-acceptor-π-bridge-acceptor (D-A-π-A) featured near-infrared (NIR) aggregation-induced emission luminogens (AIEgens)(TQTPy, TPQTPy, TQTC, and TPQTC) with type I and type II reaction oxygen species (ROS) generation capabilities are synthesized. Notably, TQTPy shows mitochondria targeted capacity, the best ROS production efficiency, long-term tumor retention capacity, and more importantly, the three-in-one fluorescence imaging guided therapy against both tumor and microbial infections. Both in vitro and in vivo results validate that TQTPy performs well in practical biomedical application in terms of NIR-fluorescence imaging-guided photodynamic cancer diagnosis and treatment. Moreover, the amphiphilic and positively charged TQTPy is able to specific and ultrafast discrimination and elimination of Gram-positive (G+) Staphylococcus aureus from Gram-negative (G-) Escherichia coli and normal cells. This investigation provides an instructive way for the construction of three-in-one treatment for image-guided photodynamic cancer therapy and bacteria elimination.

CD14 Deletion Amplifies Dahl Salt‐Sensitive Hypertension and Renal Damage through a NOX2‐dependent Mechanism

Previous work has implicated the immune system in potentiating salt‐sensitive (SS) hypertension. The innate immunity protein Cluster of Differentiation 14 (CD14), a co‐receptor with Toll‐like Receptor 4 in the inflammasome pathway of macrophages, has been associated with cardiovascular disease in humans. Interestingly, genetic deletion of CD14 in the Dahl SS rat (SSCD14‐/‐) confers a significant exacerbation of salt‐induced hypertension and associated renal disease that is specific to females. We speculated that CD14 may modulate the production of reaction oxygen species (ROS), since our previous findings implicate NADPH oxidase 2 (NOX2) derived ROS in immune cells in the pathogenesis of salt‐sensitive hypertension. In initial in vitro studies (n>4), peritoneal macrophages from Dahl SS, SSCD14‐/‐, and SSp67phox‐/‐ (a strain lacking the critical p67phox subunit of NOX2) rats were stimulated with phorbol 12‐myristate 13‐acetate, and the production of superoxide was assessed by chemiluminescence via luminol derivative L‐012. Specificity was determined using superoxide dismutase which diminished all detected signal. Superoxide release was 2.4x greater from peritoneal macrophages from female SSCD14‐/‐ when compared to SS macrophages. The SSp67phox‐/‐, lacking NOX2 activity, served as a negative control. The present study tests the hypothesis that the amplification of salt‐sensitive hypertension and renal damage in Dahl SS females lacking CD14 is mediated by NOX2. A double knockout Dahl SS rat was bred to lack both CD14 and functional NOX2 (SSCD14‐/‐p67phox‐/‐ (DKO)) to investigate a potential link between CD14 and oxidative stress. The hypertensive and kidney injury phenotype in response to a 3 week high salt challenge (HS, 4.0% NaCl, AIN‐76A) was examined in DKO females compared to SSCD14‐/‐ and SSp67phox‐/‐ females. After 3 weeks of HS, DKOrats had a significantly blunted change in mean arterial pressure (MAP) from baseline (0.4%) to HS day 21 compared to SSCD14‐/‐ rats (15 mmHg, n=3 versus 38 mmHg, n=7, p=0.01). Importantly, HS MAP in the DKO was not different than that of the SSp67phox‐/‐ (121 ± 4 mmHg versus 120 ± 2 mmHg, n=3, p>0.05), indicating that ROS production from NOX2 is likely mediating the amplified elevation of MAP following CD14 deletion. As an index of renal damage, albuminuria was significantly reduced in the DKO (11.8 ± 1.7 mg/day, n=9, p=0.004) compared to the SSCD14‐/‐ (101.8 ± 17.5 mg/day, n=12) at HS day 21. There was no difference in albuminuria between the DKO and SSp67phox‐/‐(11.7 ± 2.9 mg/day, n=7, p>0.05). Flow cytometric analysis of immune cells isolated from the kidneys of these rats indicated a reduction in renal inflammation in the DKO compared to the SSCD14‐/‐. There were fewer CD45+ total leukocytes (46% reduction), CD3+ T cells (45%), CD45R+ B cells (60%), and CD11b/c+ monocytes/macrophages (46%) in DKO (n=7) versus SSCD14‐/‐ kidneys (n=7). Together, these data suggest a role of CD14 in reducing the pathogenesis of salt‐sensitive hypertension and renal damage in a process dependent upon NOX2‐mediated oxidative stress. Here we highlight a novel renoprotective role of CD14.

Sludge-derived biochar toward sustainable Peroxymonosulfate Activation: Regulation of active sites and synergistic production of reaction oxygen species

Active sites on the surface of heterogeneous catalysts accounted for the generation of reactive oxygen species (ROS) from peroxymonosulfate (PMS) toward organic degradation. In this study, the surface chemistry of sewage sludge-derived biochar (SSB) was regulated by controlled pyrolysis and SSB was used for PMS activation and oxidation of antibiotic ciprofloxacin (CIP). SSB-20–120 achieved high CIP removal efficiencies in both batch test (94.2%) and continuous column test (96.3%) with PMS. The species and contents of Fe, N and O as active sites on SSB and their relationships with generated ROS (SO4•−, •OH, and 1O2) for CIP degradation were comprehensively identified. Fe(0), –OH, C = O and the pairwise interaction among Fe(0), Fe(II) and Fe(III) were responsible for SO4•− generation. Besides, pyrrolic N, graphitic N and the co-effect among pyridinic N, pyrrolic N and graphitic N exerted positive effects on •OH and SO4•− generation simultaneously. Meanwhile, Fe(II), Fe(III), pyrrolic N, graphitic N, lattice O with –OH, lattice O with C = O, the interactions among Fe(0), Fe(II) and Fe(III) as well as pyridinic N, pyrrolic N and graphitic N contributed to the production of •OH coupling with 1O2. Moreover, SO4•− and 1O2, as well as the co-effects of •OH with SO4•− and •OH with 1O2 were in favor of CIP degradation. This research provided new insights into the biochar synthesis, structure evolution, and the generation mechanism of reactive oxygen species from PMS activation. Outcomes are beneficial to sewage sludge utilization and developing low-cost catalysts for wastewater remediation.

Predicting and characterising protein damage in the extracellular matrix

Chronic UVR exposure of human skin can result in photo-ageing which manifests both externally and internally (as remodelling of skin layers including the extracellular matrix-rich dermis). However, the intermittent nature of UVR exposure over a timescale of decades combined with the longevity of many structural dermal proteins makes the identification of dermal photo-ageing targets and mechanisms challenging. Over the past ten years work in our group has demonstrated that: (i) proteins which are rich in amino acid chromophores are susceptible to physiologically relevant doses of solar simulated radiation, (ii) this protein degradation is mediated primarily by the photodynamic production of reaction oxygen species and (iii) UVR-chromophore rich proteins are located in tissue regions where they may act as endogenous sunscreens. We have also shown that ECM proteases selectively degrade UVR-damaged assemblies in vitro and have developed new machine learning-based models to predict protease cleavage sites and hence relative protease susceptibilities in the human skin proteome. The recent development of peptide location fingerprinting applied to conventional mass spectrometry datasets has allowed the identification of novel candidate biomarkers of UVR-induced damage as a consequence of photo-ageing. For example, this approach is able to identify structure-associated modifications in collagen VI alpha chains, although collagen VI remodeling is not evident by conventional histological analysis. These methods and resources (skin proteome database, protein susceptibility prediction and peptide location fingerprinting analysis) are available for use at www.manchesterproteome.manchester.ac.uk. Key areas for future research include using peptide location fingerprinting to: (i) characterise the structural hallmarks of ageing and photo-ageing mechanisms across different phototypes and (ii) evaluate the efficacy of rejuvenating treatments against novel protein biomarkers.

Neurotherapeutic Effect of Inula britannica var. Chinensis against H2O2-Induced Oxidative Stress and Mitochondrial Dysfunction in Cortical Neurons.

Inula britannica var. chinensis (IBC) has been used as a traditional medicinal herb to treat inflammatory diseases. Although its anti-inflammatory and anti-oxidative effects have been reported, whether IBC exerts neuroprotective effects and the related mechanisms in cortical neurons remain unknown. In this study, we investigated the effects of different concentrations of IBC extract (5, 10, and 20 µg/mL) on cortical neurons using a hydrogen peroxide (H2O2)-induced injury model. Our results demonstrate that IBC can effectively enhance neuronal viability under in vitro-modeled reaction oxygen species (ROS)-generating conditions by inhibiting mitochondrial ROS production and increasing adenosine triphosphate level in H2O2-treated neurons. Additionally, we confirmed that neuronal death was attenuated by improving the mitochondrial membrane potential status and regulating the expression of cytochrome c, a protein related to cell death. Furthermore, IBC increased the expression of brain-derived neurotrophic factor and nerve growth factor. Furthermore, IBC inhibited the loss and induced the production of synaptophysin, a major synaptic vesicle protein. This study is the first to demonstrate that IBC exerts its neuroprotective effect by reducing mitochondria-associated oxidative stress and improving mitochondrial dysfunction.

A sonosensitiser\u2010based polymeric nanoplatform for chemo\u2010sonodynamic combination therapy of lung cancer

BackgroundLung cancer is the most common type of tumour worldwide. Its relative lethality is considerably high. However, since the tumour tissues are located deep within the human body, traditional technologies, such as photodynamic therapy, do not have the desired effect. Sonosensitisers can penetrate deeply into tissues, and sonodynamic therapy (SDT) effectively inhibits tumours by generating reactive oxygen species. Ultrasound can also penetrate deeply, with a favourable tumour inhibition effect.ResultsA redox/ultrasound-responsive Rhein-chondroitin sulphate-based nano-preparation encapsulating docetaxel was fabricated. The nanoparticles displayed increased cellular uptake with quick drug release, good stability, and a monodispersed form in the physiological environment. Rhein induced apoptosis and altered mitochondrial membrane potential, which enhanced the expression of apoptosis-related proteins. SDT inhibited the metastasis and angiogenesis of cancer cells and activated anti-tumour capacity by reducing the expression of M2 macrophages.ConclusionsThe potential of Rhein for SDT was demonstrated. Production of reaction oxygen species was markedly enhanced after ultrasound treatment. The nanoplatform enhanced the synergistic anti-tumour effects of SDT and chemotherapeutic efficacy. The approach was biocompatibility. The findings could inform investigations of chemo-SDT for different cancers.

Near-Infrared Upconversion Mesoporous Tin Oxide Bio-Photocatalyst for H2O2-Activatable O2-Generating Magnetic Targeting Synergetic Treatment.

Tumor hypoxia compromises the therapeutic efficacy of oxygen (O2)-dependent treatment methods as the endogenous O2 levels have an important influence on the production of reaction oxygen species. Herein, a synergistic multifunctional mesoporous Fe@Sn-UCNPs bio-photocatalytic nanoplatform is provided to comprehensively realize endogenous hydrogen peroxide (H2O2)-activatable, self-supplied O2, photothermal performance, and near-infrared-mediated magnetic targeting PDT/PTT simultaneously for relieving tumor hypoxia. Such a nanoplatform is constructed by encapsulating magnetic Fe3O4 with lanthanide-ion-doped mesoporous tin oxide upconversion nanoparticles and further modified with phosphorylated serine and poly(ethylene glycol) for enhancing the biocompatibility and solubility. The nanoparticles can be activated by endogenous H2O2 and in situ generated O2 to relieve hypoxia through catalytic reaction. Therefore, H2O2-responsive/O2-evolving nanoparticles can elevate the O2 level in the tumor site for an apparently enhanced PDT effect in vitro and in vivo. What is more, Fe@Sn-UCNPs demonstrate enhanced photothermal conversion efficiency based on the special nanostructure and much more circuit loops for electron transitions between Fe3O4 and Sn-UCNPs, and the electronic structure of Fe@Sn-UCNPs was calculated. In addition, such Fe@Sn-UCNPs also exhibit multimodality imaging performance (including photothermal, magnetic resonance, and computed tomography imaging) for monitoring and tracking the in vivo tumor therapeutic process. This work provides novel insight into the smart Fe@Sn-UCNPs as an "all-in-one" theranostic nanosystem for cancer therapy.

Autophagy: Multiple Mechanisms to Protect Skin from Ultraviolet Radiation-Driven Photoaging.

Autophagy is an essential cellular process that maintains balanced cell life. Restriction in autophagy may induce degenerative changes in humans. Natural or pathological aging of susceptible tissues has been linked with reduced autophagic activity. Skin photoaging is an example of such pathological condition caused by ambient solar UV radiation exposure. The UV-induced production of reaction oxygen species (ROS) has been linked to the promotion and progression of the photoaging process in exposed tissues. Accordingly, it has been suggested that autophagy is capable of delaying the skin photoaging process caused by solar ultraviolet (UV), although the underlying mechanism is still under debate. This review highlights several plausible mechanisms by which UV-induced ROS activates the cellular signaling pathways and modulates the autophagy. More specifically, the UV-mediated regulation of autophagy and age-related transcription factors is discussed to pinpoint the contribution of autophagy to antiphotoaging effects in the skin. The outcome of this review will provide insights into design intervention strategies for delaying the phenomenon of sunlight-induced photodamage, photoaging, and other aging-related chronic diseases based on factors that activate the autophagy process in the skin.

Exogenous melatonin improves salt tolerance in tomato by regulating photosynthetic electron flux and the ascorbate–glutathione cycle

ABSTRACT Melatonin (MT) can protect plants against abiotic stress. In order to explore whether melatonin can improve photosynthetic function under NaCl stress, Solanum lycopersicum L. cv. Liaoyuanduoli were exposed to 150 mmol L−1 NaCl stress with or without pretreatment with 150 μmol L−1 melatonin. The results showed that NaCl stress can lead to reduced chlorophyll content, lower photosynthetic function, increased reaction oxygen species (ROS) levels, and decreased PSII activity. These changes were mainly due to the reduction in oxygen-evolving complex (OEC) activity on the donor side of PSII and the blockage of electron transfer from QA to QB on receptor side of PSII. The donor side of PSII was more sensitive to NaCl stress relative to the receptor side of PSII. Interestingly, application of MT enhanced tomato NaCl tolerance. MT reduced the production of ROS by balancing the distribution of photosynthetic electron flux, facilitated the repair of PSII by maintaining the abundance of Psb O and D1, and promoting the ability of the donor and acceptor sides of PSII to deliver electrons. MT also enhanced the scavenging ability of ROS by stimulating the activity of enzymes involved in the AsA-GSH cycle.

Dandelion root extract protects NCM460 colonic cells and relieves experimental mouse colitis.

The protective potential of dandelion on acute hepatitis, lung injury and colorectal cancer has recently been revealed. Importantly, ulcerative colitis (UC), a clinically defined inflammatory bowel disease, accelerates the risk of colorectal cancer. However, studies focusing on the activity of dandelion on UC are extremely limited. In the present study, we found that an aqueous extract of dandelion root increases cell viability and decreases apoptosis in dextran sodium sulfate (DSS)-incubated NCM460 human colonic epithelial cells, probably through removing the production of reaction oxygen species and blocking nuclear factor-kappaB signaling. We then examined the anti-colitis efficacy of this extract in an in vivo study. We detected that dandelion root extract efficiently ameliorates progressive acute injury as demonstrated by a reduction in body weight loss, severity scores of disease index and shortened colon length during DSS treatment, as well as reducing the inflammatory conditions and oxidative stress in the colon of DSS-induced mice. Our study clearly demonstrates that dandelion has a strong cytoprotective effect on NCM460 colonocytes and shows powerful defense on an established experimental mouse model of DSS-induced UC. Therefore, dandelion root extract can be an effective anti-colitis complex mixture and can provide a complementary alternative to currently available therapeutic intervention in UC.

Effects of treadmill training combined with Vitamin C or estradiol on Nitric Oxide metabolite, oxidative stress marker and liver enzymes levels in rat

: Introduction: The production of Reaction Oxygen Species (ROS), lowers cellular antioxidant levels, and enhances oxidative stress in many tissues, especially the liver. Efficient liver function is extremely important to the overall health. The key to helping prevent long-term damage is to decrease oxidative stress. The purpose of this study was to assess the effects of treadmill training with vitamin C or estradiol on nitric oxide metabolite, oxidative stress marker and liver enzymes levels in female rat. Methods: Thirty two female rats were randomly divided into four groups of 8 rats each; consisting of control (Con), training (Tr), training + vitamin C (Tr+VitC), and training+estradiol (Tr+Es) groups. Vitamin C (250 mg/kg/day) was injected three times a week for 6 weeks, and estradiol (0.25 mg/kg/week) was injected for the two first weeks. Training groups performed aerobic exercise on a treadmill 5 days/week for 6 weeks. Serum and liver tissue levels of nitrite and malondialdehyde (MDA), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in serum were determined. Results: The results showed significant reductions in the serum nitrite in Tr+VitC group (6.33±0.37µmole/l) compared with Con group (9.67± 1.39 µmole/l) and Tr group (9.91± 1.33 µmole/l) groups. While Tr group (0.22±0.02 µmole/l) exhibited lower liver nitrite compared with Con group (0.29±0.01 µmole/l) group. Serum MDA in Tr (6.68±0.31 µmole/l) and Tr+VitC (7.01±0.44 µmole/l) groups was significantly higher than in Con groups (5.20± 0.40 µmole/l). Conclusion: Our findings indicate that the treadmill training program used in this study was able to attenuate the liver oxidative stress but administration of vitamin C or estradiol couldn’t improve liver status.

The Safety and Anti-Tumor Effects of Ozonated Water in Vivo.

Ozonated water is easier to handle than ozone gas. However, there have been no previous reports on the biological effects of ozonated water. We conducted a study on the safety of ozonated water and its anti-tumor effects using a tumor-bearing mouse model and normal controls. Local administration of ozonated water (208 mM) was not associated with any detrimental effects in normal tissues. On the other hand, local administration of ozonated water (20.8, 41.6, 104, or 208 mM) directly into the tumor tissue induced necrosis and inhibited proliferation of tumor cells. There was no significant difference in the number of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end labeling (TUNEL)-positive cells following administration of ozonated water. The size of the necrotic areas was dependent on the concentration of ozonated water. These results indicate that ozonated water does not affect normal tissue and damages only the tumor tissue by selectively inducing necrosis. There is a possibility that it exerts through the production of reaction oxygen species (ROS). In addition, the induction of necrosis rather than apoptosis is very useful in tumor immunity. Based on these results, we believe that administration of ozonated water is a safe and potentially simple adjunct or alternative to existing antineoplastic treatments.

SK-N-SH 신경세포내 항산화 효과와 p38 인산화 억제에 의한 곤드레, 누룩치 그리고 산마늘의 신경 보호 효과

Oxidative stress is one of the key mechanisms involved in neuronal damage. Neuroprotective effects and underlying mechanisms of action of several wild vegetables, Cirsium setidens (CS), Pleurospermum kamtschaticumin (PK), and Allium victorials (AV), against oxidative stress induced by hydrogen peroxide in SK-N-SH cells were investigated. CS and AV up to 400 μg/mL showed no detectable effects on cell viability of human SK-N-SH neuroblastoma cells compared with control. Incubation of SK-N-SH cells with hydrogen peroxide resulted in significant induction of cell death and reaction oxygen species (ROS) production, whereas treatment of cells with CS and AV significantly reduced cell death and ROS production, respectively. Among the wild vegetables tested, CS and PK showed more effective DPPH radical scavenging activity than AV, whereas PK showed strong cytotoxicity in SK-N-SH cells compared with the control. CS showed much higher inhibitory effects on cell death and ROS generation against oxidative stress than AV. Thus, CS was selected for subsequent experiments. Ethyl acetate (EA), hexane, butanol, aqueous, and chloroform extracts from CS significantly inhibited cell death and ROS generation in SK-N-SH cells induced by oxidative stress. EA extract from CS (CS-EA) showed the highest DPPH radical-scavenging activity, intracellular ROS-scavenging activity, and neuroprotective effects. CS-EA attenuated apoptosis signal-regulating p38 activation by inhibiting phosphorylation. The findings suggest that CS-EA protects neuronal cells through antioxidant activity and inhibition of phosphorylation of p38 in brain neural cells.

Circadian Clock Control of Nox4 and Reactive Oxygen Species in the Vasculature

Recent studies have shown that circadian clock disruption is associated with pathological remodeling in the arterial structure and vascular stiffness. Moreover, chronic circadian disruption is associated with dysfunction in endothelial responses and signaling. Reactive oxygen species have emerged as key regulators in vascular pathology. Previously, we have demonstrated that circadian clock dysfunction exacerbates superoxide production through eNOS uncoupling. To date, the impact of circadian clock mutation on vascular NADPH oxidase expression and function is not known. The goal in the current study was to determine if the circadian clock controls vascular Nox4 expression and hydrogen peroxide formation in arteries, particularly in endothelial and vascular smooth muscle cells. In aorta, there was an increase in hydrogen peroxide and Nox4 expression in mice with a dysfunctional circadian rhythm (Bmal1-KO mice). In addition, the Nox4 gene promoter is activated by the core circadian transcription factors. Lastly, in synchronized cultured human endothelial cells, Nox4 gene expression exhibited rhythmic oscillations. These data reveal that the circadian clock plays an important role in the control of Nox4 and disruption of the clock leads to subsequent production of reaction oxygen species.

Surfactin-Induced Apoptosis Through ROS–ERS–Ca2+-ERK Pathways in HepG2 Cells

Although surfactin is able to inhibit cancer cell proliferation and to induce cancer cell apoptosis, the molecular mechanism responsible for this process remain elusive. In this study, the signaling network underlying the apoptosis of human hepatoma (HepG2) cells induced by surfactin was investigated. It is found that the reaction oxygen species (ROS) production and intracellular calcium ([Ca2+]i) accumulation are both induced HepG2 cells apoptosis. The [Ca2+]i exaltation was partly depended on the Ca2+ release from inositol 1,4,5-trisphosphate (IP3) and ryanodine (Ry) receptors channels, which both triggered endoplasmic reticulum stress (ERS). The results showed that surfactin induced the ROS production and ROS production led to ERS. The occurrence of ERS increased the [Ca2+]i level and the processes associated with blocking extracellular signal-regulated kinase (ERK) pathway. According to a comprehensive review of all the evidence, it is concluded that surfactin induces apoptosis of HepG2 cells through a ROS–ERS–Ca2+ mediated ERK pathway.

Antioxidant combinations protect oral fibroblasts against metal-induced toxicity

ObjectiveIn dentistry, the use of metals in fillings, braces, implants, bridges and other prosthodontic restorations is a common practice. Previous studies revealed that zinc (Zn) and copper (Cu) released from gold alloys, and nickel (Ni) released from nickel–chromium alloys, have a highly cytotoxic effect on fibroblast cell cultures. Our working hypothesis is that oral fibroblasts are susceptible to damage from metals because they elevate reaction oxygen species (ROS). In this study, we investigated specific antioxidant (AO) combinations to determine if they counteract the effects of Cu, Ni and Zn on cultured oral fibroblast proliferation and oxidative damage. MethodsOral fibroblasts were pretreated with Cu, Ni and Zn for 60min. Thereafter, cells were treated with 10-5M combinations of bioactive AO resveratrol (R), ferulic acid (F), phloretin (P) and tetrahydrocurcuminoids (T) (RFT, PFR, PFT) for 24h. Cell viability and DNA synthesis were monitored by 3-[4,5-dimethylthiazol-2-yl]-5-[3-carboxymethoxyphenyl]-2-[4-sulfophenyl]-2H-tetrazolium (MTS) and 5-bromo-2-deoxyuridine (BrDU) assays. ROS was measured using the fluorescence response of dichlorodihydrofluorescein diacetate (DCF). ResultsAO compounds increased recovery of cells exposed to Cu and Zn. Moreover, AO treatment induced DNA synthesis in the presence of the metal stressors. Cu and Ni stimulated production of ROS. PFR treatment decreased ROS in the presence of Cu, Ni and Zn. SignificanceThese data indicate that pure AOs counteracted the detrimental effects of Cu, Ni, Zn on oral fibroblasts in vitro by increasing cell viability, and DNA synthesis and decreasing ROS activity.

Combination of arsenic trioxide and BCNU synergistically triggers redox-mediated autophagic cell death in human solid tumors

Arsenic trioxide (As2O3) is an effective treatment for relapsed or refractory acute promyelocytic leukemia (APL). After the discovery of As2O3 as a promising treatment for APL, several studies investigated the use of As2O3 as a single agent in the treatment of solid tumors; however, its therapeutic efficacy is limited. Thus, the systematic study of the combination of As2O3 with other clinically used chemotherapeutic drugs to improve its therapeutic efficacy in treating human solid tumors is merited. In this study, we demonstrate for the first time, using isobologram analysis, that As2O3 exhibits a synergistic interaction with N,N′-bis(2-chloroethyl)-N-nitrosourea (BCNU). The synergistic augmentation of the cytotoxicity of As2O3 with BCNU is in part through the autophagic cell death machinery in human solid tumor cells. As2O3 and BCNU in combination produce enhanced cytotoxicity via the depletion of reduced glutathione (GSH) and augmentation of reaction oxygen species (ROS) production. Further analysis indicated that the extension of GSH depletion by this combined regimen occurs through the inhibition of the catalytic activity of glutathione reductase. Blocking ROS production with antioxidants or ROS scavengers effectively inhibits cell death and autophagy formation, indicating that redox-mediated autophagic cell death involves the synergism of As2O3 with BCNU. Taken together, this is the first evidence that BCNU could help to extend the therapeutic spectrum of As2O3. These findings will be useful in designing future clinical trials of combination chemotherapy with As2O3 and BCNU, with the potential for broad use against a variety of solid tumors.

Kaempferol acts through mitogen‐activated protein kinases and protein kinase B/AKT to elicit protection in a model of neuroinflammation in BV2 microglial cells

Kaempferol, a dietary flavonoid and phyto-oestrogen, is known to have anti-inflammatory properties. Microglial activation has been implicated in various neurodegenerative diseases. Anti-inflammatory effects of kaempferol and the underlying mechanisms were investigated by using LPS-stimulated microglial BV2 cells. Cell viability was measured using MTT and neutral red assays. elisa, Western blot, immunocytochemistry and electrophoretic mobility-shift assay were used to analyse NO, PGE(2) , TNF-α and IL-1β production, inducible NOS (iNOS), COX-2 expression and the involvement of signalling pathways such as toll-like receptor-4 (TLR4), MAPK cascades, PKB (AKT) and NF-κB. Accumulation of reaction oxygen species (ROS) was measured by nitroblue tetrazolium and 2'7'-dichlorofluorescein diacetate assay. Matrix metalloproteinase activity was investigated by zymography and immunoblot assay. Phagocytotic activity was assessed by use of latex beads. Kaempferol significantly attenuated LPS-induced NO, PGE(2) , TNF-α, IL-1β and ROS production and phagocytosis in a concentration-dependent manner. Kaempferol suppressed the expression of iNOS, COX-2, MMP-3 and blocked the TLR4 activation. Moreover, kaempferol inhibited LPS-induced NF-κB activation and p38 MAPK, JNK and AKT phosphorylation. Kaempferol was able to reduce LPS-induced inflammatory mediators through the down-regulation of TLR4, NF-κB, p38 MAPK, JNK and AKT suggesting that kaempferol has therapeutic potential for the treatment of neuroinflammatory diseases.

Modulation of apoptosis and the production of reactive oxygen species in human neutrophils with epigallocatechin-3-gallate (EGCG) (101.6)

Abstract Our laboratory has demonstrated that following thermal injury, neutrophils (PMNs) display altered immune responsiveness. Decreased apoptosis was associated with the expression of Heat Shock Protein 72 (HSP72), while increased apoptosis is associated with the production of reactive oxygen species. EGCG is an anti-oxidant found in green tea which possesses immunomodulatory properties. In this study, we investigated the effects of EGCG on PMN apoptosis and the production of reaction oxygen species. Human PMNs (HSP 72 + or −) were treated with tumor necrosis factor (TNF[alpha]) or phorbol myristate acetate (PMA), with or without EGCG. PMNs were analyzed for apoptosis, the production of superoxide anion (O2−), and hydrogen peroxide (H2O2). PMNs treated with EGCG had a significant reduction in the percentage of cells undergoing apoptosis with either agonist (by 78 and 53%, respectively). While PMNs expressing HSP72 had decreased apoptosis compared to controls, treatment with EGCG further decreased the percentage of HSP 72+ PMNs undergoing apoptosis. Treatment with EGCG significantly reduced the production of H2O2 and O2− by PMNs treated with TNF[alpha]or PMA. The data suggests that EGCG significantly reduces apoptosis, H2O2 and O2− in activated PMNs. Due to its low toxicity, ECGC may be an ideal agent to modulate the inflammatory response associated with burn injury. Supported in part by a grant from Shriners of North America

Liquid ventilation attenuates pulmonary oxidative damage

Purpose: Liquid perfluorochemicals reduce the production of reaction oxygen species by alveolar macrophages. We sought to determine whether the use of liquid perfluorochemicals in vivo during liquid ventilation would attenuate oxidative damage to the lung. Materials and Methods: Healthy infant piglets (n = 16) were instrumented for mechanical ventilation and received intravenous oleic acid to create an acute lung injury. The animals were assigned to a nontreatment group receiving conventional mechanical ventilation or a treatment group receiving partial liquid ventilation with a liquid perfluorochemical. Following sacrifice, the bronchoalveolar lavage and lung parenchyma were analyzed for evidence of oxidative damage to lipids and proteins by determination of TBARS and carbonylated protein residues, respectively. Results: Mortality in the control group was 50% at the completion of the study compared with no deaths in the partial liquid ventilation group ( P = .025). The alveolar-arterial oxygen difference was more favorable following injury in the partial liquid ventilation group. The liquid ventilation group demonstrated a 32% reduction in TBARS ( P = .043) and a 14% reduction in carbonylated protein residues ( P = .061). Conclusion: These data suggest that partial liquid ventilation supports gas exchange and reduces mortality in association with a reduction in the production of reactive oxygen species and the concomitant attenuation of tissue damage during the early phase of acute lung injury.