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Selenite-induced toxicity in cancer cells is mediated by metabolic generation of endogenous selenium nanoparticles.  

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Selenite has been a touted cancer chemopreventative agent but generates conflicting outcomes. Multiple mechanisms of selenite cytotoxicity in cancer cells are thought to be induced by metabolites of selenite. We observed that intracellular metabolism of selenite generates endogenous selenium nanoparticles (SeNPs) in cancer cells. Critical proteins that bind with high affinity to elemental selenium during SeNPs self-assembly were identified through proteomics analysis; these include glycolytic enzymes, insoluble tubulin, and heat shock proteins 90 (HSP90). Sequestration of glycolytic enzymes by SeNPs dramatically inhibits ATP generation, which leads to functional and structural disruption of mitochondria. Transcriptome sequencing showed tremendous down-regulation of mitochondrial respiratory NADH dehydrogenase (complex I), cytochrome c oxidase (complex IV), and ATP synthase (complex V) in response to glycolysis-dependent mitochondrial dysfunction. Sequestration of insoluble tubulin led to microtubule depolymerization, altering microtubule dynamics. HSP90 sequestration led to degradation of its downstream effectors via autophagy, ultimately resulting in a cell-signaling switch to apoptosis. Additionally, the surface effects of SeNPs generated oxidative stress, thus contributing to selenite cytotoxicity. Herein, we reveal that the multiple mechanisms of selenite-induced cytotoxicity are caused by endogenous protein-assisted self-assembly of SeNPs and suggest that endogenous SeNPs could potentially be the primary cause of selenite-induced cytotoxicity. PMID:25567070

Bao, Peng; Chen, Zheng; Tai, Ren-Zhong; Shen, Han-Ming; Martin, Francis L; Zhu, Yong-Guan

2015-02-01

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ROS-mediated DNA methylation pattern alterations in carcinogenesis.  

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Elevated levels of both reactive oxygen species (ROS) and DNA methylation are characteristic of various types of cancer cells. However, the relation between these two is not well understood. Here we will discuss the cause-consequence relationship between ROS and DNA methylation. Cancer research reveals that disregulation of DNA methylation results in regional CpG island hypermethylation and generalized genomic hypomethylation. ROS-induced oxidative stress is associated with both aberrant hypermethylation of tumor suppressor gene (TSG) promoter regions and global hypomethylation. The DNA oxidation structure, 8-hydroxy-2'-deoxyguanosine (8-OHdG), can induce DNA hypomethylation by inhibiting DNA methylation at nearby cytosine bases, while another DNA oxidation structure, 5-hydroxymethylcytosine (5hmC), may achieve active DNA demethylation processes, thus, causing DNA hypomethylation. Recently, it has been found that ROS can function as catalysts of DNA methylation, further accounting for TSG promoter hypermethylation. Moreover, ROS may induce site-specific hypermethylation via either the up-regulation of expression of DNA methyltransferases (DNMTs) or the formation of a new DNMT containing complex. In addition, these ROS-induced DNA methylation pattern alterations have been implicated with not only malignant transformation, but also the progression of numerous tumors. In conclusion, ROS can influence both aspects of DNA methylation changes through different mechanisms, which play an important role of epigenetic regulation in cancer cells. Therefore, the comprehension of mechanisms leading to epigenetic modifications associated with ROS may help better understand the carcinogenesis and progression, as well as aid in the development of potential biomarkers for better cancer diagnostics and novel therapeutic strategies. PMID:25585126

Wu, Qihan; Ni, Xiaohua

2015-01-01

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STAT5 triggers BCR-ABL1 mutation by mediating ROS production in chronic myeloid leukaemia  

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We recently reported that chronic myeloid leukaemia (CML) patients harbour high levels of STAT5 when they progress to advanced phases of disease. Advanced disease is characterized by an increased incidence of BCR-ABL1 mutations. We now describe a highly significant correlation between STAT5 expression and the incidence of BCR-ABL1 mutations in primary CML. Forced expression of STAT5 in murine BCR-ABL1 transformed cells sufficed to enhance the production of reactive oxygen species (ROS) and to trigger DNA damage. STAT5-mediated ROS production is independent of JAK2 but requires concomitant BCR-ABL1 signalling as forced STAT5 expression in untransformed BCR-ABL1 negative cells has no impact on ROS levels. Only within the context of a BCR-ABL1 positive cell does STAT5 transcriptionally regulate a target gene or set of genes that causes the enhanced ROS production. Our study suggests the existence of a feed-forward loop accelerating disease progression, in which BCR-ABL1 enhances its own mutation rate in a STAT5-ROS dependent manner. This model explains the increased occurrence of inhibitor-resistant BCR-ABL1 mutations in advanced disease stages driven and characterized by high STAT5 expression. PMID:23458731

Berger, Angelika; Gille, Lars; Cerny-Reiterer, Sabine; Tigan, Anca-Sarmiza; Hoelbl-Kovacic, Andrea; Valent, Peter; Moriggl, Richard; Sexl, Veronika

2012-01-01

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Preventive effect of onion juice on selenite-induced experimental cataract  

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Purpose: To evaluate the effects of onion juice on sodium-selenite induced cataract formation. Materials and Methods: Thirty-two 10-day-old Wistar-albino rat pups were divided into four equal groups. Group 1 received only subcutaneous saline injection. In Group 2, sodium-selenite (30 nmol?/?g body weight) was injected subcutaneously. In Group 3, subcutaneous sodium-selenite was injected and one drop 50% diluted fresh juice of crude onion was instilled every 8 h into the ...

Javadzadeh Alireza; Ghorbanihaghjo Amir; Bonyadi Somayeh; Rashidi Mohammad; Mesgari Mehran; Rashtchizadeh Nadereh; Argani Hassan

2009-01-01

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Artemisinin induces ROS-mediated caspase3 activation in ASTC-a-1 cells  

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Artemisinin (ART), an antimalarial phytochemical from the sweet wormwood plant or a naturally occurring component of Artemisia annua, has been shown a potential anticancer activity by apoptotic pathways. In our report, cell counting kit (CCK-8) assay showed that treatment of human lung adenocarcinoma (ASTC-a-1) cells with ART effectively increase cell death by inducing apoptosis in a time- and dose-dependent fashion. Hoechst 33258 staining was used to detect apoptosis as well. Reactive oxygen species (ROS) generation was observed in cells exposed to ART at concentrations of 400 ?M for 48 h. N-acetyl-L-cysteine (NAC), an oxygen radical scavenger, suppressed the rate of ROS generation and inhibited the ART-induced apoptosis. Moreover, AFC assay (Fluorometric assay for Caspase3 activity) showed that ROS was involved in ART-induced caspase3 acitvation. Taken together, our data indicate that ART induces ROS-mediated caspase3 activation in a time-and dose-dependent way in ASCT-a-1 cells.

Xiao, Feng-Lian; Chen, Tong-Sheng; Qu, Jun-Le; Liu, Cheng-Yi

2010-02-01

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ROS-mediated TNF-? and MIP-2 gene expression in alveolar macrophages exposed to pine dust  

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Full Text Available Abstract Background Respiratory symptoms, impaired lung function, and asthma have been reported in workers exposed to wood dust in a number of epidemiological studies. The underlying pathomechanisms, however, are not well understood. Here, we studied the effects of dust from pine (PD and heat-treated pine (HPD on the release of reactive oxygen species (ROS and inflammatory mediators in rat alveolar macrophages. Methods Tumour necrosis factor-alpha (TNF-? and macrophage inflammatory protein-2 (MIP-2 protein release, TNF-? and MIP-2 mRNA expression, and generation of ROS were studied as end points after treatment of rat alveolar macrophages with PD or HPD. In a separate series of experiments, the antioxidants glutathione and N-acetyl-L-cysteine were included in combination with wood dust. To determine the endogenous oxidative and antioxidant capacity of wood dusts, electron spin resonance (ESR spectroscopy was used. Results After 4 h incubation, both PD and HPD elicited a significantly (p Conclusion These results indicate that pine dust is able to induce expression of TNF-? and MIP-2 in rat alveolar macrophages by a mechanism that is, at least in part, mediated by ROS.

Husgafvel-Pursiainen Kirsti

2004-12-01

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Cadmium-induced teratogenicity: Association with ROS-mediated endoplasmic reticulum stress in placenta  

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The placenta is essential for sustaining the growth of the fetus. An increased endoplasmic reticulum (ER) stress has been associated with the impaired placental and fetal development. Cadmium (Cd) is a potent teratogen that caused fetal malformation and growth restriction. The present study investigated the effects of maternal Cd exposure on placental and fetal development. The pregnant mice were intraperitoneally injected with CdCl{sub 2} (4.5 mg/kg) on gestational day 9. As expected, maternal Cd exposure during early limb development significantly increased the incidences of forelimb ectrodactyly in fetuses. An obvious impairment in the labyrinth, a highly developed tissue of blood vessels, was observed in placenta of mice treated with CdCl{sub 2}. In addition, maternal Cd exposure markedly repressed cell proliferation and increased apoptosis in placenta. An additional experiment showed that maternal Cd exposure significantly upregulated the expression of GRP78, an ER chaperone. Moreover, maternal Cd exposure induced the phosphorylation of placental eIF2?, a downstream molecule of PERK signaling. In addition, maternal Cd exposure significantly increased the level of placental CHOP, another target of PERK signaling, indicating that the unfolded protein response (UPR) signaling was activated in placenta of mice treated with CdCl{sub 2}. Interestingly, alpha-phenyl-N-t-butylnitrone, a free radical spin-trapping agent, significantly alleviated Cd-induced placental ER stress and UPR. Taken together, these results suggest that reactive oxygen species (ROS)-mediated ER stress might be involved in Cd-induced impairment on placental and fetal development. Antioxidants may be used as pharmacological agents to protect against Cd-induced fetal malformation and growth restriction. -- Highlights: ? Cd induces fetal malformation and growth restriction. ? Cd induced placental ER stress and UPR. ? PBN alleviates Cd-induced ER stress and UPR in placenta. ? ROS-mediated ER stress might be involved in Cd-induced placental impairments. ? ROS-mediated ER stress might be involved in Cd-induced fetal malformations.

Wang, Zhen; Wang, Hua; Xu, Zhong Mei; Ji, Yan-Li; Chen, Yuan-Hua; Zhang, Zhi-Hui; Zhang, Cheng; Meng, Xiu-Hong; Zhao, Mei; Xu, De-Xiang, E-mail: xudex@126.com

2012-03-01

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(+)-Medioresinol leads to intracellular ROS accumulation and mitochondria-mediated apoptotic cell death in Candida albicans.  

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The phytochemical (+)-Medioresinol, a furofuran type lignan identification and isolation on the stem bark of Sambucus williamsii, which is a folk medicinal plant used in traditional medicine. (+)-Medioresinol is known to possess a lesishmanicidal activity and cardiovascular disease risk reduction but its antifungal effects have not yet been identified. In this study, to confirm (+)-Medioresinol's antifungal properties and mode of action, we observed morphological and physiological change in Candida albicans. In cells exposed to (+)-Medioresinol, arrested the cell cycle and intracellular reactive oxygen species (ROS) which is a major cause of apoptosis were increased. The increase of ROS induced oxidative stress and the mitochondria dysfunction which causes release of pro-apoptotic factors. We investigated a series of characteristic cellular changes of apoptosis by using various apoptosis detection methods. We report here for the first time that (+)-Medioresinol has effects on mitochondria and induced the accumulation of ROS in C. albicans cells. We demonstrated that one of the important features of apoptosis, mitochondrial membrane depolarization is caused by ROS. Substantially, we investigated the release of cytochrome c, which is one of the factors of metacaspase activity. We also show that the effects of (+)-Medioresinol are mediated at an early stage in apoptosis acting on the plasma membrane phosphatidylserine externalization. In addition, (+)-Medioresinol induced apoptotic morphological changes, showing the reduced cell size (low FSC) and enhanced intracellular density (high SSC). In late stage of confirmation of diagnostic markers in yeast apoptosis include the effects of nucleus morphological change, DNA fragmentation and condensation by influence of oxidative stress. These apoptotic phenomena represent that oxidative stress and mitochondria dysfunctions by inducing the phytochemical (+)-Medioresinol must be an important factors of the apoptotic process in C. albicans. These results support the elucidation of the underlying antifungal mechanisms of (+)-Medioresinol. PMID:22534194

Hwang, Ji Hong; Hwang, In-Sok; Liu, Qing-He; Woo, Eun-Rhan; Lee, Dong Gun

2012-08-01

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ROS-mediated upregulation of Noxa overcomes chemoresistance in chronic lymphocytic leukemia.  

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In recent years considerable progress has been made in treatment strategies for chronic lymphocytic leukemia (CLL). However, the disease remains incurable because of the development of chemoresistance. Strategies to overcome resistance mechanisms are therefore highly needed. At least two mechanisms contribute to the development of resistance to drugs; acquired mutations resulting in a dysfunctional p53 response and shifts in the balance between apoptosis-regulating proteins. Platinum-based compounds have been successfully applied in relapsed lymphoma and recently also in high-risk CLL. In this study we investigated the efficacy and mechanism of action of cisplatinum (CDDP) in chemorefractory CLL. Independent of p53-functional status, CDDP acted synergistically with fludarabine (F-ara-A). The response involved generation of reactive oxygen species (ROS), which led to specific upregulation of the proapoptotic BH3-only protein Noxa. Induction of Noxa resulted in cell death by apoptosis as inhibition of caspase activation completely abrogated cell death. Furthermore, drug-resistance upon CD40-ligand stimulation, a model for the protective stimuli provided in lymph nodes, could also be overcome by CDDP/F-ara-A. ROS accumulation resulted in Noxa upregulation mainly at the transcriptional level and this was, at least in part, mediated by the mitogen-activated protein kinase p38. Finally, Noxa RNA-interference markedly decreased sensitivity to CDDP/F-ara-A, supporting a key role for Noxa as mediator between ROS signaling and apoptosis induction. Our data indicate that interference in the cellular redox balance can be exploited to overcome chemoresistance in CLL. PMID:20935673

Tonino, S H; van Laar, J; van Oers, M H; Wang, J Y; Eldering, E; Kater, A P

2011-02-10

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SK3 channel and mitochondrial ROS mediate NADPH oxidase-independent NETosis induced by calcium influx.  

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Neutrophils cast neutrophil extracellular traps (NETs) to defend the host against invading pathogens. Although effective against microbial pathogens, a growing body of literature now suggests that NETs have negative impacts on many inflammatory and autoimmune diseases. Identifying mechanisms that regulate the process termed "NETosis" is important for treating these diseases. Although two major types of NETosis have been described to date, mechanisms regulating these forms of cell death are not clearly established. NADPH oxidase 2 (NOX2) generates large amounts of reactive oxygen species (ROS), which is essential for NOX-dependent NETosis. However, major regulators of NOX-independent NETosis are largely unknown. Here we show that calcium activated NOX-independent NETosis is fast and mediated by a calcium-activated small conductance potassium (SK) channel member SK3 and mitochondrial ROS. Although mitochondrial ROS is needed for NOX-independent NETosis, it is not important for NOX-dependent NETosis. We further demonstrate that the activation of the calcium-activated potassium channel is sufficient to induce NOX-independent NETosis. Unlike NOX-dependent NETosis, NOX-independent NETosis is accompanied by a substantially lower level of activation of ERK and moderate level of activation of Akt, whereas the activation of p38 is similar in both pathways. ERK activation is essential for the NOX-dependent pathway, whereas its activation is not essential for the NOX-independent pathway. Despite the differential activation, both NOX-dependent and -independent NETosis require Akt activity. Collectively, this study highlights key differences in these two major NETosis pathways and provides an insight into previously unknown mechanisms for NOX-independent NETosis. PMID:25730848

Douda, David Nobuhiro; Khan, Meraj A; Grasemann, Hartmut; Palaniyar, Nades

2015-03-01

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Activation of NADPH oxidase subunit NCF4 induces ROS-mediated EMT signaling in HeLa cells.  

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The epithelial-mesenchymal transition (EMT) is a critical biological process characterized by morphological and behavioral changes in cells. The regulatory and signaling mechanisms of both developmental and pathological EMT have been investigated. Reactive oxygen species (ROS) play a role in early EMT, but the exact mechanism by which ROS are involved is unclear. We investigated ROS-mediated EMT in human HeLa cells. Transforming growth factor beta (TGF-?) treatments lead to dramatic NADPH oxidase 2 (NOX2) inductions in HeLa cells; antioxidant treatment prevented TGF-?-driven EMT. Over-expression of the p40phox subunit (NCF4) led to activation of the NOX2 complex and ROS production. We showed that NOX2 and NOX5 mRNA was increased, along with increased expression of several matrix metalloproteinases (MMPs) in response to NCF4 expression. Moreover, these changes were reversible upon ROS scavenging. Down-regulation of E-cadherin and up-regulation of Snail, Slug and vimentin occurred at the transcriptional level. We also showed that new EMT regulator, YB-1 is a downstream target in ROS-induced EMT. Together, these data suggest that ROS switching is necessary for increased EMT but is not required for the morphological changes that accompany EMT. PMID:24378533

Kim, Young Mee; Cho, Moonjae

2014-04-01

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ROS and Sympathetically mediated Mitochondria activation in Brown Adipose Tissue contributes to Methamphetamine-induced hyperthermia  

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Full Text Available Methamphetamine abuse has been shown to induce alterations in mitochondrial function in the brain as well as to induce hyperthermia, which contributes to neurotoxicity and Meth-associated mortality. Brown adipose tissue (BAT, a thermogenic site known to be important in neonates, has recently regained importance since being identified in significant amounts and in correlation with metabolic balance in human adults. Given the high mitochondrial content of BAT and its role in thermogenesis, we aimed to investigate whether BAT plays any role in the development of Meth-induced hyperthermia. By ablating or denervating BAT, we identified a partial contribution of this organ to Meth-induced hyperthermia. BAT ablation decreased temperature by 0.5oC and reduced the length of hyperthermia by 1 hr, compared to sham-operated controls. BAT denervation also affected the development of hyperthermia in correlation with decreased the expression of electron transport chain molecules, and increase on PCG1a levels, but without affecting Meth-induced UCP1 upregulation. Furthermore, in isolated BAT cells in culture, Meth, but not Norepinephrine (NE, induced H2O2 upregulation. In addition, we found that in vivo Reactive Oxygen Species (ROS play a role in Meth hyperthermia. Thus, sympathetically- mediated mitochondrial activation in the BAT and Meth-induced ROS are key components to the development of hyperthermia in Meth abuse.

Maria CeciliaGMarcondes

2013-04-01

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Role of ROS-mediated TGF beta activation in laser photobiomodulation  

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The ability of laser light to modulate specific biological processes has been well documented but the precise mechanism mediating these photobiological interactions remains an area of intense investigation. We recently published the results of our clinical trial with 30 patients in an oral tooth-extraction wound healing model using a 904nm GaAs laser (Oralaser 1010, Oralia, Konstnaz, Germany), assessing healing parameters using routine histopathology and immunostaining (Arany et al Wound Rep Regen 2007, 15, 866). We observed a better organized healing response in laser irradiated oral tissues that correlated with an increased expression of TGF-beta1 immediately post laser irradiation. Our data suggested the source of latent TGF-beta1 might be from the degranulating platelets in the serum, an abundant source of in vivo latent TGF-beta, in the freshly wounded tissues. Further, we also demonstrated the ability of the low power near-infrared laser irradiation to activate the latent TGF-beta complexes in vitro at varying fluences from 10sec (0.1 J/cm2) to 600secs (6 J/cm2). Using serum we observed two isoforms, namely TGF-beta1 and TGF-beta3, were capable of being activated by laser irradiation using an isoform-specific ELISA and a reporter based (p3TP) assay system. We are presently pursuing the precise photomolecular mechanisms focusing on potential chromophores, wavelength and fluence parameters affecting the Latent TGF-beta activation process in serum. As ROS mediated TGF-beta activation has been previously demonstrated and we are also exploring the role of Laser generated-ROS in this activation process. In summary, we present evidence of a potential molecular mechanism for laser photobiomodulation in its ability to activate latent TGF-beta complexes.

Arany, Praveen R.; Chen, Aaron Chih-Hao; Hunt, Tristan; Mooney, David J.; Hamblin, Michael

2009-02-01

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Evaluation of anticataract potential of Triphala in selenite-induced cataract: In vitro and in vivo studies  

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Triphala (TP) is composed of Emblica officinalis, Terminalia chebula, and Terminalia belerica. The present study was undertaken to evaluate its anticataract potential in vitro and in vivo in a selenite-induced experimental model of cataract. In vitro enucleated rat lenses were maintained in organ culture containing Dulbecco’s Modified Eagles Medium alone or with the addition of 100?M selenite. These served as the normal and control groups, respectively. In the test group, the medium was su...

Gupta, Suresh Kumar; Kalaiselvan, V.; Srivastava, Sushma; Agrawal, Shyam S.; Saxena, Rohit

2010-01-01

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Dual-function nanosystem for synergetic cancer chemo-/radiotherapy through ROS-mediated signaling pathways.  

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Radioresistance and limitation of irradiative dosage usually lead to failure in depletion of hypoxic tumors. Herein we developed multifunctional mesoporous silica nanoparticles (MSNs) as a carrier of a novel anticancer selenoamino acid (selenocystine, SeC), to achieve synergistic chemo-/radiotherapy. This multifunctional nanosystem effectively sensitizes cancer cells to X-ray radiotherapy. Conjugation of TAT cell penetrating peptide and transferrin to the surface of MSNs significantly enhances its internalization in cancer cells through receptor-mediated endocytosis. SeC@MSNs-Tf/TAT significantly enhanced X-ray-induced growth inhibition in cervical cancer cells by induction of apoptosis, mainly through death receptor-mediated extrinsic apoptotic pathway. Upon radiation, SeC@MSNs-Tf/TAT promoted intracellular ROS overproduction, which induced apoptotic cell death by affecting p53, AKT and MAPKs pathways. Furthermore, SeC@MSNs-Tf/TAT also significantly inhibited HeLa tumor growth in nude mice model through suppression of cell proliferation and induction of apoptosis. In vivo toxicity of the SeC@MSNs-Tf/TAT nanoparticles was investigated using the mouse model. The results of histological analysis revealed that, the nanoparticles did not show any obvious damage to these major organs under the experimental conditions, including heart, liver, spleen, lung and kidney. Taken together, this study demonstrates an effective and safe strategy for cancer-targeted chemo-/radiotherapy of human cancers. PMID:25770995

He, Lizhen; Lai, Haoqiang; Chen, Tianfeng

2015-05-01

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ROS accumulation and IGF-IR inhibition contribute to fenofibrate/PPAR? -mediated inhibition of Glioma cell motility in vitro  

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Full Text Available Abstract Background Glioblastomas are characterized by rapid cell growth, aggressive CNS infiltration, and are resistant to all known anticancer regimens. Recent studies indicate that fibrates and statins possess anticancer potential. Fenofibrate is a potent agonist of peroxisome proliferator activated receptor alpha (PPAR? that can switch energy metabolism from glycolysis to fatty acid ?-oxidation, and has low systemic toxicity. Fenofibrate also attenuates IGF-I-mediated cellular responses, which could be relevant in the process of glioblastoma cell dispersal. Methods The effects of fenofibrate on Glioma cell motility, IGF-I receptor (IGF-IR signaling, PPAR? activity, reactive oxygen species (ROS metabolism, mitochondrial potential, and ATP production were analyzed in human glioma cell lines. Results Fenofibrate treatment attenuated IGF-I signaling responses and repressed cell motility of LN-229 and T98G Glioma cell lines. In the absence of fenofibrate, specific inhibition of the IGF-IR had only modest effects on Glioma cell motility. Further experiments revealed that PPAR?-dependent accumulation of ROS is a strong contributing factor in Glioma cell lines responses to fenofibrate. The ROS scavenger, N-acetyl-cysteine (NAC, restored cell motility, improved mitochondrial potential, and increased ATP levels in fenofibrate treated Glioma cell lines. Conclusions Our results indicate that although fenofibrate-mediated inhibition of the IGF-IR may not be sufficient in counteracting Glioma cell dispersal, PPAR?-dependent metabolic switch and the resulting ROS accumulation strongly contribute to the inhibition of these devastating brain tumor cells.

Del Valle Luis

2010-06-01

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Intrinsic resistance triggered under acid loading within normal esophageal epithelial cells: NHE1- and ROS-mediated survival.  

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The transition to a pathological phenotype such as Barrett's esophagus occurs via induction of resistance upon repeated contact with gastric refluxate in esophagus. This study examined the molecular changes within normal esophageal epithelial cells (EECs) under short-term acid loading and the role of these changes in defensive resistance against acidic cytotoxicity. After primary cultured EECs were exposed to pH 4-acidified medium (AM4), cell viability was determined by the MTT assay. Reactive oxygen species (ROS) and NAD(P)H oxidase (NOX) activity were measured. Activation of the mitogen-activated protein kinases (MAPKs) MEK/ERK1/2, p38 and JNK; phosphoinositol-3-kinase (PI3K)/Akt, and nuclear factor-kappa B (NF-?B) were detected by Western blot analysis or immunofluorescence staining. AM4 incubation induced intracellular ROS generation accompanied by increase in NOX activity, which was further increased by Na(+) /H(+) exchange-1 (NHE1)-dependent inhibition but was prevented by inhibition of NOX or mitochondria complex I. AM4 also induced phosphorylation of MEK/ERK1/2, p38 MAPK, PI3K/Akt, and nuclear translocation of NF-?B, and all these effects, except for p38 MAPK phosphorylation, were abolished by inhibition of ROS. ROS-dependent PI3K/Akt activation, which mediates NF-?B nuclear translocation, was inhibited by protein tyrosine kinase (PTK) inhibitors and NHE1-specific inhibitor. All inhibitors of NHE, ROS, PTK, PI3K, or NF-?B further decreased AM4-induced cell viability. Acid loading in the presence of NHE1-dependent protection induced ROS generation by activating NOX and mitochondria complex I, which stimulated PTK/PI3K/Akt/NF-?B-dependent survival in EEC. Our data indicate that normal EEC initially respond to acid loading through intrinsic survival activation. J. Cell. Physiol. 230: 1503-1514, 2015. © 2014 Wiley Periodicals, Inc., A Wiley Company. PMID:25522216

Park, Sun Young; Lee, Yeon Joo; Cho, Eun Jeong; Shin, Chang Yell; Sohn, Uy Dong

2015-07-01

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Cadmium-induced teratogenicity: association with ROS-mediated endoplasmic reticulum stress in placenta.  

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The placenta is essential for sustaining the growth of the fetus. An increased endoplasmic reticulum (ER) stress has been associated with the impaired placental and fetal development. Cadmium (Cd) is a potent teratogen that caused fetal malformation and growth restriction. The present study investigated the effects of maternal Cd exposure on placental and fetal development. The pregnant mice were intraperitoneally injected with CdCl(2) (4.5mg/kg) on gestational day 9. As expected, maternal Cd exposure during early limb development significantly increased the incidences of forelimb ectrodactyly in fetuses. An obvious impairment in the labyrinth, a highly developed tissue of blood vessels, was observed in placenta of mice treated with CdCl(2). In addition, maternal Cd exposure markedly repressed cell proliferation and increased apoptosis in placenta. An additional experiment showed that maternal Cd exposure significantly upregulated the expression of GRP78, an ER chaperone. Moreover, maternal Cd exposure induced the phosphorylation of placental eIF2?, a downstream molecule of PERK signaling. In addition, maternal Cd exposure significantly increased the level of placental CHOP, another target of PERK signaling, indicating that the unfolded protein response (UPR) signaling was activated in placenta of mice treated with CdCl(2). Interestingly, alpha-phenyl-N-t-butylnitrone, a free radical spin-trapping agent, significantly alleviated Cd-induced placental ER stress and UPR. Taken together, these results suggest that reactive oxygen species (ROS)-mediated ER stress might be involved in Cd-induced impairment on placental and fetal development. Antioxidants may be used as pharmacological agents to protect against Cd-induced fetal malformation and growth restriction. PMID:22252055

Wang, Zhen; Wang, Hua; Xu, Zhong Mei; Ji, Yan-Li; Chen, Yuan-Hua; Zhang, Zhi-Hui; Zhang, Cheng; Meng, Xiu-Hong; Zhao, Mei; Xu, De-Xiang

2012-03-01

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Targeting MUC1-C is synergistic with bortezomib in downregulating TIGAR and inducing ROS-mediated myeloma cell death.  

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The proteosome inhibitor bortezomib (BTZ) induces endoplasmic reticulum and oxidative stress in multiple myeloma (MM) cells. The mucin 1 C-terminal subunit (MUC1-C) oncoprotein is aberrantly expressed in most MM cells, and targeting MUC1-C with GO-203, a cell-penetrating peptide inhibitor of MUC1-C homodimerization, is effective in inducing reactive oxygen species (ROS)-mediated MM cell death. The present results demonstrate that GO-203 and BTZ synergistically downregulate expression of the p53-inducible regulator of glycolysis and apoptosis (TIGAR), which promotes shunting of glucose-6-phosphate into the pentose phosphate pathway to generate reduced glutathione (GSH). In turn, GO-203 blocks BTZ-induced increases in GSH and results in synergistic increases in ROS and MM cell death. The results also demonstrate that GO-203 is effective against BTZ-resistant MM cells. We show that BTZ resistance is associated with BTZ-induced increases in TIGAR and GSH levels, and that GO-203 resensitizes BTZ-resistant cells to BTZ treatment by synergistically downregulating TIGAR and GSH. The GO-203/BTZ combination is thus highly effective in killing BTZ-resistant MM cells. These findings support a model in which targeting MUC1-C is synergistic with BTZ in suppressing TIGAR-mediated regulation of ROS levels and provide an experimental rationale for combining GO-203 with BTZ in certain settings of BTZ resistance. PMID:24632713

Yin, Li; Kufe, Turner; Avigan, David; Kufe, Donald

2014-05-01

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Estrogen-induced DNA synthesis in vascular endothelial cells is mediated by ROS signaling  

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Full Text Available Abstract Background Since estrogen is known to increase vascular endothelial cell growth, elevated estrogen exposure from hormone replacement therapy or oral contraceptives has the potential to contribute in the development of abnormal proliferative vascular lesions and subsequent thickening of the vasculature. How estrogen may support or promote vascular lesions is not clear. We have examined in this study whether estrogen exposure to vascular endothelial cells increase the formation of reactive oxygen species (ROS, and estrogen-induced ROS is involved in the growth of endothelial cells. Methods The effect of estrogen on the production of intracellular oxidants and the role of estrogen-induced ROS on cell growth was studied in human umbilical vein endothelial cells. ROS were measured by monitoring the oxidation of 2'7'-dichlorofluorescin by spectrofluorometry. Endothelial cell growth was measured by a colorimetric immunoassay based on BrdU incorporation into DNA. Results Physiological concentrations of estrogen (367 fmol and 3.67 pmol triggered a rapid 2-fold increase in intracellular oxidants in endothelial cells. E2-induced ROS formation was inhibited to basal levels by cotreatment with the mitochondrial inhibitor rotenone (2 ?M and xanthine oxidase inhibitor allopurinol (50 ?M. Inhibitors of NAD(PH oxidase, apocynin and DPI, did not block E2-induced ROS formation. Furthermore, the NOS inhibitor, L-NAME, did not prevent the increase in E2-induced ROS. These findings indicate both mitochondria and xanthine oxidase are the source of ROS in estrogen treated vascular endothelial cells. E2 treated cells showed a 2-fold induction of BrdU incorporation at 18 h which was not observed in cells exposed to vehicle alone. Cotreatment with ebselen (20 ?M and NAC (1 mM inhibited E2-induced BrdU incorporation without affecting the basal levels of DNA synthesis. The observed inhibitory effect of NAC and ebselen on E2-induced DNA synthesis was also shown to be dose dependent. Conclusion We have shown that estrogen exposure stimulates the rapid production of intracellular ROS and they are involved in growth signaling of endothelial cells. It appears that the early estrogen signaling does not require estrogen receptor genomic signaling because we can inhibit estrogen-induced DNA synthesis by antioxidants. Findings of this study may further expand research defining the underlying mechanism of how estrogen may promote vascular lesions. It also provides important information for the design of new antioxidant-based drugs or new antioxidant gene therapy to protect the cardiovascular health of individuals sensitive to estrogen.

Felty Quentin

2006-04-01

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ABA-mediated ROS in mitochondria regulate root meristem activity by controlling PLETHORA expression in Arabidopsis.  

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Although research has determined that reactive oxygen species (ROS) function as signaling molecules in plant development, the molecular mechanism by which ROS regulate plant growth is not well known. An aba overly sensitive mutant, abo8-1, which is defective in a pentatricopeptide repeat (PPR) protein responsible for the splicing of NAD4 intron 3 in mitochondrial complex I, accumulates more ROS in root tips than the wild type, and the ROS accumulation is further enhanced by ABA treatment. The ABO8 mutation reduces root meristem activity, which can be enhanced by ABA treatment and reversibly recovered by addition of certain concentrations of the reducing agent GSH. As indicated by low ProDR5:GUS expression, auxin accumulation/signaling was reduced in abo8-1. We also found that ABA inhibits the expression of PLETHORA1 (PLT1) and PLT2, and that root growth is more sensitive to ABA in the plt1 and plt2 mutants than in the wild type. The expression of PLT1 and PLT2 is significantly reduced in the abo8-1 mutant. Overexpression of PLT2 in an inducible system can largely rescue root apical meristem (RAM)-defective phenotype of abo8-1 with and without ABA treatment. These results suggest that ABA-promoted ROS in the mitochondria of root tips are important retrograde signals that regulate root meristem activity by controlling auxin accumulation/signaling and PLT expression in Arabidopsis. PMID:25522358

Yang, Li; Zhang, Jing; He, Junna; Qin, Yingying; Hua, Deping; Duan, Ying; Chen, Zhizhong; Gong, Zhizhong

2014-12-01

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ROS-Mediated Cytotoxic Effect of Copper(II Hydrazone Complexes against Human Glioma Cells  

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Full Text Available 2-Acetylpyridine acetylhydrazone (H2AcMe, 2-benzoylpyridine acetylhydrazone (H2BzMe and complexes [Cu(H2AcMeCl2] (1 and [Cu(H2BzMeCl2] (2 were assayed for their cytotoxicity against wild type p53 U87 and mutant p53 T98 glioma cells, and against MRC-5 fibroblast cells. Compounds 1 and 2 proved to be more active than the corresponding hydrazones against U87, but not against T98 cells. Compound 1 induced higher levels of ROS than H2AcMe in both glioma cell lines. H2AcMe and 1 induced lower levels of ROS in MRC5 than in U87 cells. Compound 2 induced lower levels of ROS in MRC5 than in T98 cells. The cytotoxic effect of 1 in U87 cells could be related to its ability to provoke the release of ROS, suggesting that the cytotoxicity of 1 might be somehow p53 dependent.

Angel A. Recio Despaigne

2014-10-01

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Nickel (II)-induced cytotoxicity and apoptosis in human proximal tubule cells through a ROS- and mitochondria-mediated pathway  

Energy Technology Data Exchange (ETDEWEB)

Nickel compounds are known to be toxic and carcinogenic in kidney and lung. In this present study, we investigated the roles of reactive oxygen species (ROS) and mitochondria in nickel (II) acetate-induced cytotoxicity and apoptosis in the HK-2 human renal cell line. The results showed that the cytotoxic effects of nickel (II) involved significant cell death and DNA damage. Nickel (II) increased the generation of ROS and induced a noticeable reduction of mitochondrial membrane potential (MMP). Analysis of the sub-G1 phase showed a significant increase in apoptosis in HK-2 cells after nickel (II) treatment. Pretreatment with N-acetylcysteine (NAC) not only inhibited nickel (II)-induced cell death and DNA damage, but also significantly prevented nickel (II)-induced loss of MMP and apoptosis. Cell apoptosis triggered by nickel (II) was characterized by the reduced protein expression of Bcl-2 and Bcl-xL and the induced the protein expression of Bad, Bcl-Xs, Bax, cytochrome c and caspases 9, 3 and 6. The regulation of the expression of Bcl-2-family proteins, the release of cytochrome c and the activation of caspases 9, 3 and 6 were inhibited in the presence of NAC. These results suggest that nickel (II) induces cytotoxicity and apoptosis in HK-2 cells via ROS generation and that the mitochondria-mediated apoptotic signaling pathway may be involved in the positive regulation of nickel (II)-induced renal cytotoxicity.

Wang, Yi-Fen; Shyu, Huey-Wen [Department of Medical Laboratory Sciences and Biotechnology, Fooyin University, Kaohsiung, Taiwan (China); Chang, Yi-Chuang [Department of Nursing, Fooyin University, Kaohsiung, Taiwan (China); Tseng, Wei-Chang [Department of Medical Laboratory Sciences and Biotechnology, Fooyin University, Kaohsiung, Taiwan (China); Huang, Yeou-Lih [Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Lin, Kuan-Hua; Chou, Miao-Chen; Liu, Heng-Ling [Department of Medical Laboratory Sciences and Biotechnology, Fooyin University, Kaohsiung, Taiwan (China); Chen, Chang-Yu, E-mail: mt037@mail.fy.edu.tw [Department of Medical Laboratory Sciences and Biotechnology, Fooyin University, Kaohsiung, Taiwan (China)

2012-03-01

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Protective role of new nitrogen compounds on ROS/RNS-mediated damage to PC12 cells  

OpenAIRE

Reactive oxygen (ROS) and nitrogen (RNS) species are known to be involved in many degenerative diseases. This study reports four new nitrogen compounds from organic synthesis, identified as FMA4, FMA7, FMA762 and FMA796, which differ mainly by the number of hydroxyl groups within their phenolic unit. Their potential role as antioxidants was evaluated in PC12 cells by assessing their protection against oxidative and nitrosative insults. The four compounds, and particularly FMA762 a...

Silva, Joa?o P.; Proenc?a, M. Fernanda R. P.; Coutinho, O. P.

2008-01-01

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Vascular patterning regulates interdigital cell death by a ROS-mediated mechanism.  

Science.gov (United States)

Blood vessels serve as key regulators of organogenesis by providing oxygen, nutrients and molecular signals. During limb development, programmed cell death (PCD) contributes to separation of the digits. Interestingly, prior to the onset of PCD, the autopod vasculature undergoes extensive patterning that results in high interdigital vascularity. Here, we show that in mice, the limb vasculature positively regulates interdigital PCD. In vivo, reduction in interdigital vessel number inhibited PCD, resulting in syndactyly, whereas an increment in vessel number and distribution resulted in elevation and expansion of PCD. Production of reactive oxygen species (ROS), toxic compounds that have been implicated in PCD, also depended on interdigital vascular patterning. Finally, ex vivo incubation of limbs in gradually decreasing oxygen levels led to a correlated reduction in both ROS production and interdigital PCD. The results support a role for oxygen in these processes and provide a mechanistic explanation for the counterintuitive positive role of the vasculature in PCD. In conclusion, we suggest a new role for vascular patterning during limb development in regulating interdigital PCD by ROS production. More broadly, we propose a double safety mechanism that restricts PCD to interdigital areas, as the genetic program of PCD provides the first layer and vascular patterning serves as the second. PMID:25617432

Eshkar-Oren, Idit; Krief, Sharon; Ferrara, Napoleone; Elliott, Alison M; Zelzer, Elazar

2015-02-15

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Patulin Induces Apoptosis through ROS-Mediated Endoplasmic Reticulum Stress Pathway.  

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Patulin (PAT) is a toxic metabolite produced by several filamentous fungi of the genera of Penicillium, Aspergillus, and Byssochlamys. PAT is the most common mycotoxin found in apples and apple-based products including juice, compotes, cider, and baby food. Exposure to this mycotoxin has been reported to induce intestinal and kidney injuries. This study investigated the mechanism of PAT-induced toxicity in human colon carcinoma (HCT116) and embryonic kidney cells (HEK293). We demonstrated that PAT activated endoplasmic reticulum (ER) and unfolded protein response as evidenced by up-regulation of GRP78 and GADD34, splicing of XBP1 mRNA, and expression of the proapoptotic factor CHOP. This ER stress response was accompanied by the induction of the mitochondrial apoptotic pathway. Apoptosis occurred with ROS production, drop in mitochondrial membrane potential and caspase activation. Further, we showed that deficiency of the proapoptotic protein Bax or Bak protected cells against PAT-induced apoptosis. The treatment of cells with the ROS scavenger N-acetyl cysteine inhibits the ER stress response and prevents mitochondrial apoptosis. Collectively, our data provide new mechanistic insights in the signaling pathways of the cell death induced by PAT and demonstrate that PAT induces cytotoxicity through a ROS-dependent mechanism involving ER stress and activation of mitochondrial apoptotic pathway in human intestinal and kidney cells. PMID:25577197

Boussabbeh, Manel; Ben Salem, Intidhar; Prola, Alexandre; Guilbert, Arnaud; Bacha, Hassen; Abid-Essefi, Salwa; Lemaire, Christophe

2015-04-01

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Upregulation of Hsp72 mediates anoxia/reoxygenation neuroprotection in the freshwater turtle via modulation of ROS.  

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The neuroprotective role of Hsp72 has been demonstrated in several ischemic/stroke models to occur primarily through mediation of apoptotic pathways, and a number of heat shock proteins are upregulated in animal models capable of extended anoxic survival. In the present study, we investigated the role of Hsp72 on cell death and apoptotic regulators in one anoxia tolerant model system, the freshwater turtle Trachemys scripta. Since Hsp72 is known to regulate apoptosis through interactions with Bcl-2, we manipulated the levels of Hsp72 and Bcl-2 with siRNA in neuronally enriched primary cell cultures and examined downstream effects. The knockdown of either Hsp72 or Bcl-2 induced cell death during anoxia and reoxygenation. Knockdown of Bcl-2 resulted in increases in apoptotic markers and increased ROS levels 2-fold. However, significant knockdown of Hsp72 did not have any effect on the expression of key mitochondrial apoptotic regulators such as Cytochrome c and caspase-3. Hsp72 knockdown however significantly increased apoptosis inducing factor in both anoxia and reoxygenation and resulted in a six-fold induction of hydrogen peroxide levels. These findings suggest that the neuroprotection offered by Hsp72 in the anoxia/reoxygenation tolerant turtle is through the mediation of ROS levels and not through modulation of caspase-dependent pathways. PMID:25107858

Kesaraju, Shailaja; Nayak, Gauri; Prentice, Howard M; Milton, Sarah L

2014-09-25

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Evaluation of anticataract potential of Triphala in selenite-induced cataract: In vitro and in vivo studies.  

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Triphala (TP) is composed of Emblica officinalis, Terminalia chebula, and Terminalia belerica. The present study was undertaken to evaluate its anticataract potential in vitro and in vivo in a selenite-induced experimental model of cataract. In vitro enucleated rat lenses were maintained in organ culture containing Dulbecco's Modified Eagles Medium alone or with the addition of 100?M selenite. These served as the normal and control groups, respectively. In the test group, the medium was supplemented with selenite and different concentrations of TP aqueous extract. The lenses were incubated for 24 h at 37°C. After incubation, the lenses were processed to estimate reduced glutathione (GSH), lipid peroxidation product, and antioxidant enzymes. In vivo selenite cataract was induced in 9-day-old rat pups by subcutaneous injection of sodium selenite (25 ?mole/kg body weight). The test groups received 25, 50, and 75 mg/kg of TP intraperitoneally 4 h before the selenite challenge. At the end of the study period, the rats' eyes were examined by slit-lamp. TP significantly (P < 0.01) restored GSH and decreased malondialdehyde levels. A significant restoration in the activities of antioxidant enzymes such as superoxide dismutase (P < 0.05), catalase (P < 0.05), glutathione peroxidase (P < 0.05), and glutathione-s-transferase (P < 0.005) was observed in the TP-supplemented group compared to controls. In vivo TF 25mg/kg developed only 20% nuclear cataract as compared to 100% in control. TP prevents or retards experimental selenite-induced cataract. This effect may be due to antioxidant activity. Further studies are warranted to explore its role in human cataract. PMID:21731375

Gupta, Suresh Kumar; Kalaiselvan, V; Srivastava, Sushma; Agrawal, Shyam S; Saxena, Rohit

2010-10-01

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STAT5 triggers BCR-ABL1 mutation by mediating ROS production in chronic myeloid leukaemia  

OpenAIRE

We recently reported that chronic myeloid leukaemia (CML) patients harbour high levels of STAT5 when they progress to advanced phases of disease. Advanced disease is characterized by an increased incidence of BCR-ABL1 mutations. We now describe a highly significant correlation between STAT5 expression and the incidence of BCR-ABL1 mutations in primary CML. Forced expression of STAT5 in murine BCR-ABL1 transformed cells sufficed to enhance the production of reactive oxygen species (ROS) and to...

Warsch, Wolfgang; Grundschober, Eva; Berger, Angelika; Gille, Lars; Cerny-reiterer, Sabine; Tigan, Anca-sarmiza; Hoelbl-kovacic, Andrea; Valent, Peter; Moriggl, Richard; Sexl, Veronika

2012-01-01

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Induction of apoptosis in HL-60 cells through the ROS-mediated mitochondrial pathway by ramentaceone from Drosera aliciae.  

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Ramentaceone (1) is a naphthoquinone constituent of Drosera aliciae that exhibits potent cytotoxic activity against various tumor cell lines. However, its molecular mechanism of cell death induction has still not been determined. The present study demonstrates that 1 induces apoptosis in human leukemia HL-60 cells. Typical morphological and biochemical features of apoptosis were observed in 1-treated cells. Compound 1 induced a concentration-dependent increase in the sub-G1 fraction of the cell cycle. A decrease in the mitochondrial transmembrane potential (??m) was also observed. Furthermore, 1 reduced the ratio of anti-apoptotic Bcl-2 to pro-apoptotic Bax and Bak, induced cytochrome c release, and increased the activity of caspase 3. The generation of reactive oxygen species (ROS) was detected in 1-treated HL-60 cells, which was attenuated by the pretreatment of cells with a free radical scavenger, N-acetylcysteine (NAC). NAC also prevented the increase of the sub-G1 fraction induced by 1. These results indicate that ramentaceone induces cell death through the ROS-mediated mitochondrial pathway. PMID:22250825

Kawiak, Anna; Zawacka-Pankau, Joanna; Wasilewska, Aleksandra; Stasilojc, Grzegorz; Bigda, Jacek; Lojkowska, Ewa

2012-01-27

31

Tumor-targeting novel manganese complex induces ROS-mediated apoptotic and autophagic cancer cell death.  

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In this study, the antitumor activity of the novel manganese (II) compound, Adpa-Mn {[(Adpa)Mn(Cl)(H(2)O)] (Adpa=bis(2-pyridylmethyl)amino-2-propionic acid)}, and its possible mechanisms of action were investigated. In vitro, the growth inhibitory effects of Adpa-Mn (with IC(50) values lower than 15 µM) on tumor cell lines were examined by MTT assay. We found that this compound was more selective against cancer cells than the popular chemotherapeutic reagent, cisplatin. We then found that Adpa-Mn achieved its selectivity against cancer cells through the transferrin (Tf)-transferrin receptor (TfR) system, which is highly expressed in tumor cells. Furthermore, Adpa-Mn induced both apoptosis and autophagy, as indicated by chromatin condensation, the activation of poly(ADP-ribose) polymerase (PARP), Annexin V/propidium iodide staining, an enhanced fluorescence intensity of monodansylcadaverine (MDC), as well as the elevated expression of the autophagy-related protein, microtubule-associated protein 1 light chain 3 (LC3). In addition, Adpa-Mn induced the generation of intracellular reactive oxygen species (ROS) and its anticancer effects were significantly reduced following pre-treatment with the antioxidant, N-acetyl cysteine, indicating that ROS triggered cell death. In vivo, the induction of apoptosis and autophagy in tumor tissue was confirmed following treatment with Adpa-Mn, which contributed to its significant antitumor activity against hepatocellular carcinoma (Hep-A cell) xenografts at 10 mg/kg. Taken together, these data suggest the possible use of Adpa-Mn as a novel anticancer drug. PMID:25604962

Liu, Jia; Guo, Wenjie; Li, Jing; Li, Xiang; Geng, Ji; Chen, Qiuyun; Gao, Jing

2015-03-01

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Coenzyme Q10 Protects Astrocytes from ROS-Induced Damage through Inhibition of Mitochondria-Mediated Cell Death Pathway  

Science.gov (United States)

Coenzyme Q10 (CoQ10) acts by scavenging reactive oxygen species to protect neuronal cells against oxidative stress in neurodegenerative diseases. The present study was designed to examine whether CoQ10 was capable of protecting astrocytes from reactive oxygen species (ROS) mediated damage. For this purpose, ultraviolet B (UVB) irradiation was used as a tool to induce ROS stress to cultured astrocytes. The cells were treated with 10 and 25 ?g/ml of CoQ10 for 3 or 24 h prior to the cells being exposed to UVB irradiation and maintained for 24 h post UVB exposure. Cell viability was assessed by MTT conversion assay. Mitochondrial respiration was assessed by respirometer. While superoxide production and mitochondrial membrane potential were measured using fluorescent probes, levels of cytochrome C (cyto-c), cleaved caspase-9, and caspase-8 were detected using Western blotting and/or immunocytochemistry. The results showed that UVB irradiation decreased cell viability and this damaging effect was associated with superoxide accumulation, mitochondrial membrane potential hyperpolarization, mitochondrial respiration suppression, cyto-c release, and the activation of both caspase-9 and -8. Treatment with CoQ10 at two different concentrations started 24 h before UVB exposure significantly increased the cell viability. The protective effect of CoQ10 was associated with reduction in superoxide, normalization of mitochondrial membrane potential, improvement of mitochondrial respiration, inhibition of cyto-c release, suppression of caspase-9. Furthermore, CoQ10 enhanced mitochondrial biogenesis. It is concluded that CoQ10 may protect astrocytes through suppression of oxidative stress, prevention of mitochondrial dysfunction, blockade of mitochondria-mediated cell death pathway, and enhancement of mitochondrial biogenesis. PMID:25552930

Jing, Li; He, Mao-Tao; Chang, Yue; Mehta, Suresh L.; He, Qing-Ping; Zhang, Jian-Zhong; Li, P. Andy

2015-01-01

33

Sodium fluoride induces apoptosis in mouse embryonic stem cells through ROS-dependent and caspase- and JNK-mediated pathways  

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Sodium fluoride (NaF) is used as a source of fluoride ions in diverse applications. Fluoride salt is an effective prophylactic for dental caries and is an essential element required for bone health. However, fluoride is known to cause cytotoxicity in a concentration-dependent manner. Further, no information is available on the effects of NaF on mouse embryonic stem cells (mESCs). We investigated the mode of cell death induced by NaF and the mechanisms involved. NaF treatment greater than 1 mM reduced viability and DNA synthesis in mESCs and induced cell cycle arrest in the G{sub 2}/M phase. The addition of NaF induced cell death mainly by apoptosis rather than necrosis. Catalase (CAT) treatment significantly inhibited the NaF-mediated cell death and also suppressed the NaF-mediated increase in phospho-c-Jun N-terminal kinase (p-JNK) levels. Pre-treatment with SP600125 or z-VAD-fmk significantly attenuated the NaF-mediated reduction in cell viability. In contrast, intracellular free calcium chelator, but not of sodium or calcium ion channel blockers, facilitated NaF-induced toxicity in the cells. A JNK specific inhibitor (SP600125) prevented the NaF-induced increase in growth arrest and the DNA damage-inducible protein 45?. Further, NaF-mediated loss of mitochondrial membrane potential was apparently inhibited by pifithrin-? or CAT inhibitor. These findings suggest that NaF affects viability of mESCs in a concentration-dependent manner, where more than 1 mM NaF causes apoptosis through hydroxyl radical-dependent and caspase- and JNK-mediated pathways. -- Highlights: ? The mode of NaF-induced cell death and the mechanisms involved were examined. ? NaF induced mainly apoptotic death of mouse embryonic stem cells (mESCs). ? NaF induced mitochondrial-mediated and caspase-dependent apoptosis. ? JNK- and p53-mediated pathways are involved in NaF-mediated apoptosis in the cells. ? ROS are the up-stream effector in NaF-mediated activation of JNK and p53 in mESCs.

Nguyen Ngoc, Tam Dan [Institute of Oral Biosciences and School of Dentistry (BK21 Program), Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Son, Young-Ok [Graduate Center for Toxicology, School of Medicine, University of Kentucky, Lexington, KY 40536-0305 (United States); Lim, Shin-Saeng [Institute of Oral Biosciences and School of Dentistry (BK21 Program), Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Department of Bioactive Material Sciences and Research Center of Bioactive Materials, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Shi, Xianglin [Graduate Center for Toxicology, School of Medicine, University of Kentucky, Lexington, KY 40536-0305 (United States); Kim, Jong-Ghee [Institute of Oral Biosciences and School of Dentistry (BK21 Program), Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Heo, Jung Sun [Department of Maxillofacial Biomedical Engineering and Institute of Oral Biology, School of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Choe, Youngji [Institute of Oral Biosciences and School of Dentistry (BK21 Program), Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Jeon, Young-Mi, E-mail: young@jbnu.ac.kr [Institute of Oral Biosciences and School of Dentistry (BK21 Program), Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Lee, Jeong-Chae, E-mail: leejc88@jbnu.ac.kr [Institute of Oral Biosciences and School of Dentistry (BK21 Program), Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Graduate Center for Toxicology, School of Medicine, University of Kentucky, Lexington, KY 40536-0305 (United States); Department of Bioactive Material Sciences and Research Center of Bioactive Materials, Chonbuk National University, Jeonju 561-756 (Korea, Republic of)

2012-03-15

34

Prolonged exposure of cortical neurons to oligomeric amyloid-? impairs NMDA receptor function via NADPH oxidase-mediated ROS production: protective effect of green tea (–-epigallocatechin-3-gallate  

Directory of Open Access Journals (Sweden)

Full Text Available Excessive production of A? (amyloid ?-peptide has been shown to play an important role in the pathogenesis of AD (Alzheimer's disease. Although not yet well understood, aggregation of A? is known to cause toxicity to neurons. Our recent study demonstrated the ability for oligomeric A? to stimulate the production of ROS (reactive oxygen species in neurons through an NMDA (N-methyl-d-aspartate-dependent pathway. However, whether prolonged exposure of neurons to aggregated A? is associated with impairment of NMDA receptor function has not been extensively investigated. In the present study, we show that prolonged exposure of primary cortical neurons to A? oligomers caused mitochondrial dysfunction, an attenuation of NMDA receptor-mediated Ca2+ influx and inhibition of NMDA-induced AA (arachidonic acid release. Mitochondrial dysfunction and the decrease in NMDA receptor activity due to oligomeric A? are associated with an increase in ROS production. Gp91ds-tat, a specific peptide inhibitor of NADPH oxidase, and Mn(III-tetrakis(4-benzoic acid-porphyrin chloride, an ROS scavenger, effectively abrogated A?-induced ROS production. Furthermore, A?-induced mitochondrial dysfunction, impairment of NMDA Ca2+ influx and ROS production were prevented by pre-treatment of neurons with EGCG [(?-epigallocatechin-3-gallate], a major polyphenolic component of green tea. Taken together, these results support a role for NADPH oxidase-mediated ROS production in the cytotoxic effects of A?, and demonstrate the therapeutic potential of EGCG and other dietary polyphenols in delaying onset or retarding the progression of AD.

Grace Y Sun

2011-02-01

35

Optogenetic control of ROS production  

Directory of Open Access Journals (Sweden)

Full Text Available Reactive Oxygen Species (ROS are known to cause oxidative damage to DNA, proteins and lipids. In addition, recent evidence suggests that ROS can also initiate signaling cascades that respond to stress and modify specific redox-sensitive moieties as a regulatory mechanism. This suggests that ROS are physiologically-relevant signaling molecules. However, these sensor/effector molecules are not uniformly distributed throughout the cell. Moreover, localized ROS damage may elicit site-specific compensatory measures. Thus, the impact of ROS can be likened to that of calcium, a ubiquitous second messenger, leading to the prediction that their effects are exquisitely dependent upon their location, quantity and even the timing of generation. Despite this prediction, ROS signaling is most commonly intuited through the global administration of chemicals that produce ROS or by ROS quenching through global application of antioxidants. Optogenetics, which uses light to control the activity of genetically-encoded effector proteins, provides a means of circumventing this limitation. Photo-inducible genetically-encoded ROS-generating proteins (RGPs were originally employed for their phototoxic effects and cell ablation. However, reducing irradiance and/or fluence can achieve sub-lethal levels of ROS that may mediate subtle signaling effects. Hence, transgenic expression of RGPs as fusions to native proteins gives researchers a new tool to exert spatial and temporal control over ROS production. This review will focus on the new frontier defined by the experimental use of RGPs to study ROS signaling.

Andrew P. Wojtovich

2014-01-01

36

Resistance to ROS1 Inhibition Mediated by EGFR Pathway Activation in Non-Small Cell Lung Cancer  

Science.gov (United States)

The targeting of oncogenic ‘driver’ kinases with small molecule inhibitors has proven to be a highly effective therapeutic strategy in selected non-small cell lung cancer (NSCLC) patients. However, acquired resistance to targeted therapies invariably arises and is a major limitation to patient care. ROS1 fusion proteins are a recently described class of oncogenic driver, and NSCLC patients that express these fusions generally respond well to ROS1-targeted therapy. In this study, we sought to determine mechanisms of acquired resistance to ROS1 inhibition. To accomplish this, we analyzed tumor samples from a patient who initially responded to the ROS1 inhibitor crizotinib but eventually developed acquired resistance. In addition, we generated a ROS1 inhibition-resistant derivative of the initially sensitive NSCLC cell line HCC78. Previously described mechanisms of acquired resistance to tyrosine kinase inhibitors including target kinase-domain mutation, target copy number gain, epithelial-mesenchymal transition, and conversion to small cell lung cancer histology were found to not underlie resistance in the patient sample or resistant cell line. However, we did observe a switch in the control of growth and survival signaling pathways from ROS1 to EGFR in the resistant cell line. As a result of this switch, ROS1 inhibition-resistant HCC78 cells became sensitive to EGFR inhibition, an effect that was enhanced by co-treatment with a ROS1 inhibitor. Our results suggest that co-inhibition of ROS1 and EGFR may be an effective strategy to combat resistance to targeted therapy in some ROS1 fusion-positive NSCLC patients. PMID:24349229

Davies, Kurtis D.; Mahale, Sakshi; Astling, David P.; Aisner, Dara L.; Le, Anh T.; Hinz, Trista K.; Vaishnavi, Aria; Bunn, Paul A.; Heasley, Lynn E.; Tan, Aik-Choon; Camidge, D. Ross; Varella-Garcia, Marileila; Doebele, Robert C.

2013-01-01

37

Curcumin Induced Human Gastric Cancer BGC-823 Cells Apoptosis by ROS-Mediated ASK1-MKK4-JNK Stress Signaling Pathway  

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Full Text Available The signaling mediated by stress-activated MAP kinases (MAPK, c-Jun N-terminal kinase (JNK has well-established importance in cancer. In the present report, we investigated the effects of curcumin on the signaling pathway in human gastric cancer BGC-823 cells. Curcumin induced reactive oxygen species (ROS production and BGC-823 cells apoptosis. Inhibition of ROS generation by antioxidant (NAC or Trion significantly prevented curcumin-mediated apoptosis. Notably, we observed that curcumin activated ASK1, a MAPKKK that is oxidative stress sensitive and responsible to phosphorylation of JNK via triggering cascades, up-regulated an upstream effector of the JNK, MKK4, and phosphorylated JNK protein expression in BGC-823 cells. However, curcumin induced ASK1-MKK4-JNK signaling was attenuated by NAC. All the findings confirm the possibility that oxidative stress-activated ASK1-MKK4-JNK signaling cascade promotes the apoptotic response in curcumin-treated BGC-823 cells.

Tao Liang

2014-09-01

38

A selenium-containing ruthenium complex as a cancer radiosensitizer, rational design and the important role of ROS-mediated signalling.  

Science.gov (United States)

A novel selenium-containing ruthenium complex Ru(phtpy)(phenSe)Cl(ClO4) (phtpy = 4-phenyl-2,2':6',2''-terpyridine, phenSe = 2-selenicimidazole[4,5-f]1,10-phenanthroline) has been synthesized and found be able to enhance radiation-induced DNA damage through superoxide overproduction, which leads to G2/M arrest and apoptosis in cancer cells by activating ROS-mediated pathways. PMID:25574525

Deng, Zhiqin; Yu, Lianling; Cao, Wenqiang; Zheng, Wenjie; Chen, Tianfeng

2015-02-14

39

CARDIAC MITOCHONDRIA AND ROS GENERATION  

OpenAIRE

Mitochondrial ROS have emerged as an important mechanism of disease and redox signaling in the cardiovascular system. Under basal or pathological conditions, electron leakage for ROS production is primarily mediated by the electron transport chain and proton motive force consisting of a membrane potential (??) and a proton gradient (?pH). Several factors controlling ROS production in mitochondria include FMN and the FMN-binding domain of complex I, ubisemiquinone and quinone-binding domain...

Chen, Yeong-renn; Zweier, Jay L.

2014-01-01

40

Loss of mitochondrial exo/endonuclease EXOG affects mitochondrial respiration and induces ROS-mediated cardiomyocyte hypertrophy.  

Science.gov (United States)

Recently, a locus at the mitochondrial exo/endonuclease EXOG gene, which has been implicated in mitochondrial DNA repair, was associated with cardiac function. The function of EXOG in cardiomyocytes is still elusive. Here we investigated the role of EXOG in mitochondrial function and hypertrophy in cardiomyocytes. Depletion of EXOG in primary neonatal rat ventricular cardiomyocytes (NRVCs) induced a marked increase in cardiomyocyte hypertrophy. Depletion of EXOG, however, did not result in loss of mitochondrial DNA integrity. Although EXOG depletion did not induce fetal gene expression and common hypertrophy pathways were not activated, a clear increase in ribosomal S6 phosphorylation was observed, which readily explains increased protein synthesis. With the use of a Seahorse flux analyzer, it was shown that the mitochondrial oxidative consumption rate (OCR) was increased 2.4-fold in EXOG-depleted NRVCs. Moreover, ATP-linked OCR was 5.2-fold higher. This increase was not explained by mitochondrial biogenesis or alterations in mitochondrial membrane potential. Western blotting confirmed normal levels of the oxidative phosphorylation (OXPHOS) complexes. The increased OCR was accompanied by a 5.4-fold increase in mitochondrial ROS levels. These increased ROS levels could be normalized with specific mitochondrial ROS scavengers (MitoTEMPO, mnSOD). Remarkably, scavenging of excess ROS strongly attenuated the hypertrophic response. In conclusion, loss of EXOG affects normal mitochondrial function resulting in increased mitochondrial respiration, excess ROS production, and cardiomyocyte hypertrophy. PMID:25377088

Tigchelaar, Wardit; Yu, Hongjuan; de Jong, Anne Margreet; van Gilst, Wiek H; van der Harst, Pim; Westenbrink, B Daan; de Boer, Rudolf A; Silljé, Herman H W

2015-01-15

41

DNA mediated assembly of quantum dot-protoporphyrin IX FRET probes and the effect of FRET efficiency on ROS generation.  

Science.gov (United States)

Photodynamic therapy (PDT) involves generation of reactive oxygen species (ROS) by the irradiation of a photosensitizer. Controlled and targeted release of ROS by a photosensitizer is crucial in PDT. For achieving controlled generation of ROS, a ZnSe/ZnS quantum dot (QD) donor and protoporphyrin IX (Pp IX) acceptor based fluorescence resonance energy transfer (FRET) probe is reported here. The QDs and Pp IX are assembled either by direct conjugation or through DNA hybridization. Complementary DNA strands are individually conjugated to the QDs and Pp IX by amide coupling. Due to the overlap of the emission spectrum of QDs and the absorption spectrum of Pp IX, efficient transfer of energy from QDs to Pp IX was observed in both the cases. The FRET efficiency was quantitatively evaluated by steady-state and time-resolved spectroscopy and compared between the QD-Pp IX direct conjugate and QD-DNA-Pp IX assembly at various donor to acceptor ratios. Since a single QD can harbor a multiple number of Pp IX-DNA counterparts through DNA hybridization, the FRET efficiency was found to increase with the increase in the number of Pp IX acceptors. ROS generation from Pp IX was studied for the FRET pairs and was found to be affected by the irradiation time of the QD donor. PMID:25639515

Singh, Seema; Chakraborty, Anirban; Singh, Vandana; Molla, Aniruddha; Hussain, Sahid; Singh, Manoj K; Das, Prolay

2015-02-28

42

Natural borneol, a monoterpenoid compound, potentiates selenocystine-induced apoptosis in human hepatocellular carcinoma cells by enhancement of cellular uptake and activation of ROS-mediated DNA damage.  

Science.gov (United States)

Selenocystine (SeC) has been identified as a novel compound with broad-spectrum anticancer activities. Natural borneol (NB) is a monoterpenoid compound that has been used as a promoter of drug absorption. In the present study, we demonstrated that NB significantly enhanced the cellular uptake of SeC and potentiated its antiproliferative activity on HepG2 cells by induction of apoptosis. NB effectively synergized with SeC to reduce cancer cell growth through the triggering apoptotic cell death. Further mechanistic studies by Western blotting showed that treatment of the cells with NB and SeC activated the intrinsic apoptotic pathway by regulation of pro-survival and pro-apoptotic Bcl-2 family proteins. Treatment of the cells with NB and SeC induced the activation of p38MAPK and inactivation of Akt and ERK. NB also potentiated SeC to trigger intracellular ROS generation and DNA strand breaks as examined by Comet assay. Moreover, the thiol-reducing antioxidants effectively blocked the occurrence of cell apoptosis, which confirmed the important role of ROS in cell apoptosis. Taken together, these results reveal that NB strongly potentiates SeC-induced apoptosis in cancer cells by enhancement of cellular uptake and activation of ROS-mediated DNA damage. NB could be further developed as a chemosensitizer of SeC in treatment of human cancers. PMID:23700426

Su, Jianyu; Lai, Haoqiang; Chen, Jianping; Li, Lin; Wong, Yum-Shing; Chen, Tianfeng; Li, Xiaoling

2013-01-01

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Snake venom toxin from vipera lebetina turanica induces apoptosis of colon cancer cells via upregulation of ROS- and JNK-mediated death receptor expression  

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Full Text Available Abstract Background Abundant research suggested that the cancer cells avoid destruction by the immune system through down-regulation or mutation of death receptors. Therefore, it is very important that finding the agents that increase the death receptors of cancer cells. In this study, we demonstrated that the snake venom toxin from Vipera lebetina turanica induce the apoptosis of colon cancer cells through reactive oxygen species (ROS and c-Jun N-terminal kinases (JNK dependent death receptor (DR4 and DR5 expression. Methods We used cell viability assays, DAPI/TUNEL assays, as well as western blot for detection of apoptosis related proteins and DRs to demonstrate that snake venom toxin-induced apoptosis is DR4 and DR5 dependent. We carried out transient siRNA knockdowns of DR4 and DR5 in colon cancer cells. Results We showed that snake venom toxin inhibited growth of colon cancer cells through induction of apoptosis. We also showed that the expression of DR4 and DR5 was increased by treatment of snake venom toxin. Moreover, knockdown of DR4 or DR5 reversed the effect of snake venom toxin. Snake venom toxin also induced JNK phosphorylation and ROS generation, however, pretreatment of JNK inhibitor and ROS scavenger reversed the inhibitory effect of snake venom toxin on cancer cell proliferation, and reduced the snake venom toxin-induced upregulation of DR4 and DR5 expression. Conclusions Our results indicated that snake venom toxin could inhibit human colon cancer cell growth, and these effects may be related to ROS and JNK mediated activation of death receptor (DR4 and DR5 signals.

Park Mi

2012-06-01

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PKC? phosphorylation is an upstream event of GSK3 inactivation-mediated ROS generation in TGF-?1-induced senescence.  

Science.gov (United States)

Transforming growth factor ?1 (TGF-?1) induces Mv1Lu cell senescence through inactivating glycogen synthase kinase 3 (GSK3), thereby inactivating complex IV and increasing intracellular ROS. In the present study, we identified protein kinase C delta (PKC?) as an upstream regulator of GSK3 inactivation in this mechanism of TGF-?1-induced senescence. When Mv1Lu cells were exposed to TGF-?1, PKC? phosphorylation simultaneously increased with GSK3 phosphorylation, and then AKT and ERK were phosphorylated. AKT phosphorylation and Smad signaling were independent of GSK3 phosphorylation, but ERK phosphorylation was downstream of GSK3 inactivation. TGF-?1-triggered GSK3 phosphorylation was blocked by inhibition of PKC?, using its pharmacological inhibitor, Rottlerin, or overexpression of a dominant negative PKC? mutant, but GSK3 inhibition with SB415286 did not alter PKC? phosphorylation. Activation of PKC? by PMA delayed cell growth and increased intracellular ROS level, but did not induce senescent phenotypes. In addition, overexpression of wild type or a constitutively active PKC? mutant was enough to delay cell growth and decrease the mitochondrial oxygen consumption rate and complex IV activity, but weakly induce senescence. However, PMA treatment on Mv1Lu cells, which overexpress wild type and constitutively active PKC? mutants, effectively induced senescence. These results indicate that PKC? plays a key role in TGF-?1-induced senescence of Mv1Lu cells through the phosphorylation of GSK3, thereby triggering mitochondrial complex IV dysfunction and intracellular ROS generation. PMID:24917460

Byun, H-O; Jung, H-J; Kim, M-J; Yoon, G

2014-09-01

45

Reactive Oxygen Species (ROS Scavenging in Hot Air Preconditioning Mediated Alleviation of Chilling Injury in Banana Fruits  

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Full Text Available Banana fruits (Musa sp., AAA group, Cavendish subgroup cv. ‘Williams’ were exposed to two hot air treatment regimes namely 50oC for 10 minutes (HAT A and 40oC for 60 minutes (HAT B. The fruits were then stored at chilling temperatures (8oC for up to 21 days to evaluate the efficacy the treatments on chilling injury (CI alleviation and activity of reactive oxygen species (ROS following the treatments. The hot air treatments initially disrupted normal cellular functions as evidenced by higher percentage of initial ion leakage. However upon transfer to cold storage, the trend was reversed and ion leakage was higher in the untreated controls compared to the treated bananas. Symptoms of CI appeared earlier (5th day and progressed faster in the untreated controls compared to the treated bananas. The slow progression of CI in treated bananas was accompanied by increased reactive oxygen species (ROS scavenging capacity. This was evidenced by higher activity of antioxidant enzymes including superoxide dismutase (SOD, catalase (CAT, guaiacol peroxidase (POD and ascorbate peroxidase (APX, in the treated bananas. Similarly, the components of the ascorbate-glutathione cycle were positively affected by the hot air treatments. The content of reduced glutathione (GSH and reduced ascorbic acid (AsA were slightly higher, contributing to the higher antioxidant potential in the treated bananas; this further enhanced the ROS scavenging capacity. Moreover the activity of glutathione reductase (GR which is essential in recycling glutathione was slightly higher in the treated bananas. These results indicate that the increased antioxidants’ content and antioxidant enzymes’ activity triggered by hot air treatments positively enhanced the bananas’ tolerance to chilling temperature.

Jane Ambuko

2012-12-01

46

Induction of Apoptosis by Costunolide in Bladder Cancer Cells is Mediated through ROS Generation and Mitochondrial Dysfunction  

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Full Text Available Despite the availability of several therapeutic options, a safer and more effective modality is urgently needed for treatment of bladder cancer. Costunolide, a member of sesquiterpene lactone family, possesses potent anticancer properties. In this study, for the first time we investigated the effects of costunolide on the cell viability and apoptosis in human bladder cancer T24 cells. Treatment of T24 cells with costunolide resulted in a dose-dependent inhibition of cell viability and induction of apoptosis which was associated with the generation of ROS and disruption of mitochondrial membrane potential (??m. These effects were significantly blocked when the cells were pretreated with N-acetyl- cysteine (NAC, a specific ROS inhibitor. Exposure of T24 cells to costunolide was also associated with increased expression of Bax, down-regulation of Bcl-2, survivin and significant activation of caspase-3, and its downstream target PARP. These findings provide the rationale for further in vivo and clinical investigation of costunolide against human bladder cancer.

Ichiro Tsuji

2013-01-01

47

Ebselen induces reactive oxygen species (ROS)-mediated cytotoxicity in Saccharomyces cerevisiae with inhibition of glutamate dehydrogenase being a target?  

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Ebselen is a synthetic, lipid-soluble seleno-organic compound. The high electrophilicity of ebselen enables it to react with multiple cysteine residues of various proteins. Despite extensive research on ebselen, its target molecules and mechanism of action remains less understood. We performed biochemical as well as in vivo experiments employing budding yeast as a model organism to understand the mode of action of ebselen. The growth curve analysis and FACS (florescence activated cell sorting) assays revealed that ebselen exerts growth inhibitory effects on yeast cells by causing a delay in cell cycle progression. We observed that ebselen exposure causes an increase in intracellular ROS levels and mitochondrial membrane potential, and that these effects were reversed by addition of antioxidants such as reduced glutathione (GSH) or N-acetyl-l-cysteine (NAC). Interestingly, a significant increase in ROS levels was noticed in gdh3-deleted cells compared to wild-type cells. Furthermore, we showed that ebselen inhibits GDH function by interacting with its cysteine residues, leading to the formation of inactive hexameric GDH. Two-dimensional gel electrophoresis revealed protein targets of ebselen including CPR1, the yeast homolog of Cyclophilin A. Additionally, ebselen treatment leads to the inhibition of yeast sporulation. These results indicate a novel direct connection between ebselen and redox homeostasis. PMID:24490132

Azad, Gajendra?Kumar; Singh, Vikash; Mandal, Papita; Singh, Prabhat; Golla, Upendarrao; Baranwal, Shivani; Chauhan, Sakshi; Tomar, Raghuvir S.

2014-01-01

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Fucoidan Derived from Undaria pinnatifida Induces Apoptosis in Human Hepatocellular Carcinoma SMMC-7721 Cells via the ROS-Mediated Mitochondrial Pathway  

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Full Text Available Fucoidans, fucose-enriched sulfated polysaccharides isolated from brown algae and marine invertebrates, have been shown to exert anticancer activity in several types of human cancer, including leukemia and breast cancer and in lung adenocarcinoma cells. In the present study, the anticancer activity of the fucoidan extracted from the brown seaweed Undaria pinnatifida was investigated in human hepatocellular carcinoma SMMC-7721 cells, and the underlying mechanisms of action were investigated. SMMC-7721 cells exposed to fucoidan displayed growth inhibition and several typical features of apoptotic cells, such as chromatin condensation and marginalization, a decrease in the number of mitochondria, and in mitochondrial swelling and vacuolation. Fucoidan-induced cell death was associated with depletion of reduced glutathione (GSH, accumulation of high intracellular levels of reactive oxygen species (ROS, and accompanied by damage to the mitochondrial ultrastructure, depolarization of the mitochondrial membrane potential (MMP, ??m and caspase activation. Moreover, fucoidan led to altered expression of factors related to apoptosis, including downregulating Livin and XIAP mRNA, which are members of the inhibitor of apoptotic protein (IAP family, and increased the Bax-to-Bcl-2 ratio. These findings suggest that fucoidan isolated from U. pinnatifida induced apoptosis in SMMC-7721 cells via the ROS-mediated mitochondrial pathway.

Lin Hou

2013-06-01

49

Quinazoline analog HMJ-30 inhibits angiogenesis: involvement of endothelial cell apoptosis through ROS-JNK-mediated death receptor 5 signaling.  

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The aim of the present study was to explore the effect of 6-fluoro-2-(3-fluorophenyl)-4-(cyanoanilino) quinazoline (HMJ-30) on the anti-angiogenic properties and apoptosis-related mechanism of human umbilical vein endothelial cells (HUVECs). In this study, HMJ-30 dose- and time-dependently inhibited the viability of HUVECs. We also found that HMJ-30 enhanced disruption of tube-like structures and suppressed cell migration in HUVECs after vascular endothelial growth factor (VEGF) induction. HMJ-30 was also observed to inhibit vessel branching and sprouting in chicken chorioallantoic membrane (CAM). Microsprouting induced by VEGF in the rat aortic ring and blood vessel formation in a mouse Matrigel plug were individually suppressed by HMJ-30. In an in vitro study, HMJ-30 induced the apoptotic death of HUVECs as indicated by DNA fragmentation and promoted reactive oxygen species (ROS) production as determined by flow cytometric assay. In addition, extrinsic caspase signaling (caspase-8 and -3) was activated in the HMJ-30-treated HUVECs and their inhibitors were applied to assess the signal transduction. We investigated the upstream of the death receptor pathway and further observed that the levels of death receptor 5 (DR5) and phosphorylated c-Jun N-terminal kinase (JNK) signals were upregulated in HUVECs following HMJ-30 challenge, which was confirmed by a JNK-specific inhibitor (SP600125). Hence, HMJ-30-induced endothelial cell apoptosis involved the ROS/JNK-regulated DR5 pathway. In summary, HMJ-30 may provide a potential therapeutic effect for the anti-vascular targeting of angiogenesis during cancer treatment. PMID:24919794

Lu, Chi-Cheng; Chen, Hao-Ping; Chiang, Jo-Hua; Jin, Yi-An; Kuo, Sheng-Chu; Wu, Tian-Shung; Hour, Mann-Jen; Yang, Jai-Sing; Chiu, Yu-Jen

2014-08-01

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Protective Efficacy of Vitamins C and E on p,p?-DDT-Induced Cytotoxicity via the ROS-Mediated Mitochondrial Pathway and NF-?B/FasL Pathway  

Science.gov (United States)

Dichlorodiphenoxytrichloroethane (DDT) is a known persistent organic pollutant and liver damage toxicant. However, there has been little emphasis on the mechanism underlying liver damage toxicity of DDT and the relevant effective inhibitors. Hence, the present study was conducted to explore the protective effects of vitamin C (VC) and vitamin E (VE) on the cytotoxicity of DDT in HL-7702 cells and elaborate the specific molecular mechanisms. The results demonstrated that p,p?-DDT exposure at over 10 µM depleted cell viability of HL-7702 cells and led to cell apoptotic. p,p?-DDT treatment elevated the level of reactive oxygen species (ROS) generation, induced mitochondrial membrane potential, and released cytochrome c into the cytosol, with subsequent elevations of Bax and p53, along with suppression of Bcl-2. In addition, the activations of caspase-3 and -8 were triggered. Furthermore, p,p?-DDT promoted the expressions of NF-?B and FasL. When the cells were exposed to the NF-?B inhibitor (PDTC), the up-regulated expression of FasL was attenuated. Strikingly, these alterations caused by DDT treatment were prevented or reversed by the addition of VC or VE, and the protective effects of co-treatment with VC and VE were higher than the single supplement with p,p?-DDT. Taken together, these findings provide novel experimental evidences supporting that VC or/and VE could reduce p,p?-DDT-induced cytotoxicity of HL-7702 cells via the ROS-mediated mitochondrial pathway and NF-?B/FasL pathway. PMID:25464339

Jin, Xiaoting; Song, Li; Liu, Xiangyuan; Chen, Meilan; Li, Zhuoyu; Cheng, Long; Ren, Hua

2014-01-01

51

Vibrio vulnificus VvhA induces NF-?B-dependent mitochondrial cell death via lipid raft-mediated ROS production in intestinal epithelial cells.  

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The Gram-negative bacterium Vibrio vulnificus produces hemolysin (VvhA), which induces cytotoxicity in mammalian cells. However, our understanding of the cytotoxic mechanism and the modes of action of VvhA are still fragmentary and incomplete. The recombinant protein (r) VvhA (50?pg/ml) significantly induces necrotic cell death and apoptosis in human intestinal epithelial (INT-407) cells. The apoptotic cell death induced by rVvhA is highly susceptible to the sequestration of cholesterol by methyl-?-cyclodextrin, whereas for necrotic cell death, this shows a marginal effect. We found that rVvhA induces the aggregation of lipid raft components coupled with NADPH oxidase enzymes, in which rVvhA increased the interaction of NADPH oxidase 2 (NOX2, gp91(phox)) with a cytosolic protein NCF1 (p47(phox)) to facilitate the production of reactive oxygen species (ROS). rVvhA uniquely stimulated a conventional PKC isoform PKC? and induced the phosphorylation of both ERK and JNK, which are responsible for the activation of transcription factor NF-?B. rVvhA induced an NF-?B-dependent imbalance of the Bcl-2/Bax ratio, the release of mitochondrial cytochrome c, and caspase-3/-9 activation during its promotion of apoptotic cell death. In addition, rVvhA has the ability to inhibit the expression of cell cycle-related proteins, such as CDK2, CDK4, cyclin D1, and cyclin E. These results demonstrate that rVvhA induces NF-?B-dependent mitochondrial cell death via lipid raft-mediated ROS production by the distinct activation of PKC? and ERK/JNK in intestinal epithelial cells. PMID:25695598

Lee, S-J; Jung, Y H; Oh, S Y; Song, E J; Choi, S H; Han, H J

2015-01-01

52

ROS accumulation and IGF-IR inhibition contribute to fenofibrate/PPAR? -mediated inhibition of Glioma cell motility in vitro  

OpenAIRE

Abstract Background Glioblastomas are characterized by rapid cell growth, aggressive CNS infiltration, and are resistant to all known anticancer regimens. Recent studies indicate that fibrates and statins possess anticancer potential. Fenofibrate is a potent agonist of peroxisome proliferator activated receptor alpha (PPAR?) that can switch energy metabolism from glycolysis to fatty acid ?-oxidation, and has low systemic toxicity. Fenofibrate also attenuates IGF-I-mediated cellular response...

Del Valle Luis; Wybieralska Ewa; Grabacka Maja; Wilk Anna; Urbanska Katarzyna; Drukala Justyna; Madeja Zbigniew; Reiss Krzysztof

2010-01-01

53

Strategy to Suppress Oxidative Damage-Induced Neurotoxicity in PC12 Cells by Curcumin: the Role of ROS-Mediated DNA Damage and the MAPK and AKT Pathways.  

Science.gov (United States)

Oxidative damage plays a key role in causation and progression of neurodegenerative diseases. Inhibition of oxidative stress represents one of the most effective ways in treating human neurologic diseases. Herein, we evaluated the protective effect of curcumin on PC12 cells against H2O2-induced neurotoxicity and investigated its underlying mechanism. The results indicated that curcumin pre-treatment significantly suppressed H2O2-induced cytotoxicity, inhibited the loss of mitochondrial membrane potential (??m) through regulation of Bcl-2 family expression, and ultimately reversed H2O2-induced apoptotic cell death in PC12 cells. Attenuation of caspase activation, poly(ADP-ribose) polymerase (PARP) cleavage, DNA damage, and accumulation of reactive oxygen species (ROS) all confirmed its protective effects. Moreover, curcumin markedly alleviated the dysregulation of the MAPK and AKT pathways induced by H2O2. Taken together, our findings suggest that the strategy of using curcumin could be a highly effective way in combating oxidative damage-mediated human neurodegenerative diseases. PMID:25432891

Fu, Xiao-Yan; Yang, Ming-Feng; Cao, Ming-Zhi; Li, Da-Wei; Yang, Xiao-Yi; Sun, Jing-Yi; Zhang, Zong-Yong; Mao, Lei-Lei; Zhang, Shuai; Wang, Feng-Ze; Zhang, Feng; Fan, Cun-Dong; Sun, Bao-Liang

2014-11-30

54

TCA Cycle-Mediated Generation of ROS Is a Key Mediator for HeR-MRSA Survival under ?-Lactam Antibiotic Exposure  

OpenAIRE

Methicillin-resistant Staphylococcus aureus (MRSA) is a major multidrug resistant pathogen responsible for several difficult-to-treat infections in humans. Clinical Hetero-resistant (HeR) MRSA strains, mostly associated with persistent infections, are composed of mixed cell populations that contain organisms with low levels of resistance (hetero-resistant HeR) and those that display high levels of drug resistance (homo-resistant HoR). However, the full understanding of ?-lactam-mediated HeR/...

Rosato, Roberto R.; Fernandez, Regina; Paz, Liliana I.; Singh, Christopher R.; Rosato, Adriana E.

2014-01-01

55

Arsenic and chromium in drinking water promote tumorigenesis in a mouse colitis-associated colorectal cancer model and the potential mechanism is ROS-mediated Wnt/?-catenin signaling pathway  

International Nuclear Information System (INIS)

Exposure to carcinogenic metals, such as trivalent arsenic [As(III)] and hexavalent chromium [Cr(VI)], through drinking water is a major global public health problem and is associated with various cancers. However, the mechanism of their carcinogenicity remains unclear. In this study, we used azoxymethane/dextran sodium sulfate (AOM/DSS)-induced mouse colitis-associated colorectal cancer model to investigate their tumorigenesis. Our results demonstrate that exposure to As(III) or Cr(VI), alone or in combination, together with AOM/DSS pretreatment has a promotion effect, increasing the colorectal tumor incidence, multiplicity, size, and grade, as well as cell inflammatory response. Two-dimensional differential gel electrophoresis coupled with mass spectrometry revealed that As(III) or Cr(VI) treatment alone significantly changed the density of proteins. The expression of ?-catenin and phospho-GSK was increased by treatment of carcinogenic metals alone. Concomitantly, the expression of NADPH oxidase1 (NOX1) and the level of 8-OHdG were also increased by treatment of carcinogenic metals alone. Antioxidant enzymes, such as superoxide dismutase (SOD) and catalase, were decreased. Similarly, in an in vitro system, exposure of CRL-1807 to carcinogenic metals increased reactive oxygen species (ROS) generation, the expression of ?-catenin, phospho-GSK, and NOX1. Inhibition of ROS generation by addition of SOD or catalase inhibited ?-catenin expression and activity. Our study provides a new animal model to study the carcinogenicity of As(III) and Cr(VI) and suggests that As(III) and Cr(VI) promote colorectal cancer tumorigenesis, at least partly, through ROS-mediated Wnt/?-catenin signaling pathway. -- Highlights: ? Carcinogenic metals in drinking water promote colorectal tumor formation in vivo. ? Carcinogenic metals induce ?-catenin activation in vivo and in vitro. ? ROS generation induced by carcinogenic metals mediated ?-catenin activation.

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Nitric oxide signals ROS scavenger-mediated enhancement of PAL activity in nitrogen-deficient Matricaria chamomilla roots: side effects of scavengers.  

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Owing to the abundance of phenolic metabolites in plant tissue, their accumulation represents an important tool for stress protection. However, the regulation of phenolic metabolism is still poorly known. The regulatory role of reactive oxygen species (ROS) in the activity of phenylalanine ammonia-lyase (PAL) in nitrogen (N)-deficient chamomile roots treated for 24 h was studied using three ROS scavengers [dithiothreitol (DTT), salicylhydroxamic acid, and sodium benzoate]. Scavengers decreased the level of hydrogen peroxide and/or superoxide (and up-regulated ascorbate/guaiacol peroxidase and glutathione reductase), but, surprisingly, stimulated PAL activity. This up-regulation was correlated with increases in nitric oxide (NO) content, total soluble phenols, selected phenolic acids, and, partially, lignin (being expressed the most in DTT-exposed roots). We therefore tested the hypothesis that NO may be involved in these changes. Application of 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO) decreased PAL activity and the accumulation of soluble phenols in all treatments. Exogenous H(2)O(2) and NO also stimulated PAL activity and the accumulation of phenols. We conclude that NO, in addition to hydrogen peroxide, may regulate PAL activity during N deficiency. The anomalous effect of PTIO on NO content and possible mechanism of ROS scavenger-evoked NO increases in light of the current knowledge are also discussed. PMID:19345259

Kovácik, Jozef; Klejdus, Borivoj; Backor, Martin

2009-06-15

57

Assessment of in-utero venlafaxine induced, ROS-mediated, apoptotic neurodegeneration in fetal neocortex and neurobehavioral sequelae in rat offspring.  

Science.gov (United States)

Venlafaxine (VEN), a serotonin and noradrenaline reuptake inhibitor is being used as a drug of choice for treating clinical depression even during pregnancy. It is an important therapeutic option in the treatment of perinatal depression, but the effects of VEN on fetus and the newborn are uncertain. Therefore, present study was undertaken to investigate the safety of in-utero exposure to VEN in terms of developmental neurotoxicity and neurodegenerative potential by using prenatal rat model. The selected doses of VEN (25, 40 and 50mg/kg) were administered to pregnant rats from GD 5 to 19 through oral gavage. The fetal brains were dissected and processed for histopathological measurements of neocortical thickness that showed significant reduction. Considering vulnerability of immature brain to free radical injury, VEN exposed neocortices were tested for reactive oxygen species (ROS) levels which were significantly increased. As ROS play important role in the initiation of apoptotic mechanisms, we explored for in situ detection of apoptosis by confocal microscopy that showed enhanced apoptosis including chromatin condensation which was further reconfirmed by electron microscopy. Substantially increased levels of pro-apoptotic protein Bax and decreased levels of anti-apoptotic protein Bcl2 as shown by western blotting also supported the increased neuro-apoptotic degeneration. For further correlation of these findings, prenatally VEN exposed young-adult rat offspring were assessed for open field exploratory behavior that showed increased anxiety-like and stereotypic responses indicating disturbed neurobehavioral pattern. The study concludes that prenatal VEN exposure may primarily enhance ROS generation that plays a key role in regulating release of proapoptotic factors from mitochondria and thereby enhancing apoptotic neurodegeneration that affect proliferation, migration and differentiation of cells, resulting in neuronal deficits manifested as long term neurobehavioral impairments. PMID:25450524

Singh, Manish; Singh, K P; Shukla, Shubha; Dikshit, Madhu

2015-02-01

58

Luteolin inhibits Cr(VI)-induced malignant cell transformation of human lung epithelial cells by targeting ROS mediated multiple cell signaling pathways.  

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Hexavalent chromium [Cr(VI)] is a well-known human carcinogen associated with the incidence of lung cancer. Inhibition of metal induced carcinogenesis by a dietary antioxidant is a novel approach. Luteolin, a natural dietary flavonoid found in fruits and vegetables, possesses potent antioxidant and anti-inflammatory activity. We found that short term exposure of human bronchial epithelial cells (BEAS-2B) to Cr(VI) (5?M) showed a drastic increase in ROS generation, NADPH oxidase (NOX) activation, lipid peroxidation, and glutathione depletion, which were significantly inhibited by the treatment with luteolin in a dose dependent manner. Treatment with luteolin decreased AP-1, HIF-1?, COX-2, and iNOS promoter activity induced by Cr(VI) in BEAS-2B cells. In addition, luteolin protected BEAS-2B cells from malignant transformation induced by chronic Cr(VI) exposure. Moreover, luteolin also inhibited the production of pro-inflammatory cytokines (IL-1?, IL-6, IL-8, TNF-?) and VEGF in chronic Cr(VI) exposed BEAS-2B cells. Western blot analysis showed that luteolin inhibited multiple gene products linked to survival (Akt, Fak, Bcl-2, Bcl-xL), inflammation (MAPK, NF-?B, COX-2, STAT-3, iNOS, TNF-?) and angiogenesis (HIF-1?, VEGF, MMP-9) in chronic Cr(VI) exposed BEAS-2B cells. Nude mice injected with BEAS-2B cells chronically exposed to Cr(VI) in the presence of luteolin showed reduced tumor incidence compared to Cr(VI) alone treated group. Overexpression of catalase (CAT) or SOD2, eliminated Cr(VI)-induced malignant transformation. Overall, our results indicate that luteolin protects BEAS-2B cells from Cr(VI)-induced carcinogenesis by scavenging ROS and modulating multiple cell signaling mechanisms that are linked to ROS. Luteolin, therefore, serves as a potential chemopreventive agent against Cr(VI)-induced carcinogenesis. PMID:25448439

Pratheeshkumar, Poyil; Son, Young-Ok; Divya, Sasidharan Padmaja; Roy, Ram Vinod; Hitron, John Andrew; Wang, Lei; Kim, Donghern; Dai, Jin; Asha, Padmaja; Zhang, Zhuo; Wang, Yitao; Shi, Xianglin

2014-12-01

59

Snake venom toxin from Vipera lebetina turanica sensitizes cancer cells to TRAIL through ROS- and JNK-mediated upregulation of death receptors and downregulation of survival proteins.  

Science.gov (United States)

We investigated whether snake venom toxin (SVT) from Vipera lebetina turanica enhances the apoptosis ability of tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) in cancer cells. TRAIL inhibited HCT116 cell growth in a dose-dependent manner; however, this reduction did not occur in TRAIL resistant HT-29, A549 and HepG2 cells with an even higher dose of TRAIL. SVT, but not TRAIL enhanced expression of cell death receptor (DR) in TRAIL resistant cancer cells in a dose-dependent manner. A combination of SVT with TRAIL significantly inhibited cell growth of TRAIL resistant HT-29, A549 and HepG2 cells. Consistent with cell growth inhibition, the expression of TRAIL receptors; DR4 and DR5 was significantly increased as well as apoptosis related proteins such as cleaved caspase-3, -8, -9 and Bax. However, the expression of survival proteins (e.g., cFLIP, survivin, XIAP and Bcl2) was suppressed by the combination treatment of SVT and TRAIL. Depletion of DR4 or DR5 by small interfering RNA significantly reversed the cell growth inhibitory and apoptosis blocking effects of SVT in HCT116 and HT-29 cells. Pretreatment with the c-Jun N-terminal kinase (JNK) inhibitor SP600125 and the reactive oxygen species (ROS) scavenger N-acetylcysteine reduced the SVT and TRAIL-induced upregulation of DR4 and DR5 expression, expression of the apoptosis related protein such as caspase-3 and-9, as well as cell growth inhibitory effects. The collective results suggest that SVT facilitates TRAIL-induced apoptosis in cancer cells through up-regulation of the TRAIL receptors; DR4 and DR5 via ROS/JNK pathway signals. PMID:23007278

Park, Mi Hee; Jo, Miran; Won, Dohee; Song, Ho Sueb; Song, Min Jong; Hong, Jin Tae

2012-12-01

60

ROS Installation and Commissioning  

CERN Multimedia

The ATLAS Readout group (a sub-group of TDAQ) has now completed the installation and commissioning of all of the Readout System (ROS) units. Event data from ATLAS is initially handled by detector specific hardware and software, but following a Level 1 Accept the data passes from the detector specific Readout Drivers (RODs) to the ROS, the first stage of the central ATLAS DAQ. Within the final ATLAS TDAQ system the ROS stores the data and on request makes it available to the Level 2 Trigger (L2) processors and to the Event Builder (EB) as required. The ROS is implemented as a large number of PCs housing custom built cards (ROBINs) and running custom multi-threaded software. Each ROBIN card (shown below) contains buffer memories to store the data, plus a field programmable gate array ( FPGA ) and an embedded PowerPC processor for management of the memories and data requests, and is implemented as a 64-bit 66 MHz PCI card. Both the software and the ROBIN cards have been designed and developed by the Readout g...

Gorini, B

61

Ammonia-induced Na,K-ATPase/ouabain-mediated EGF receptor transactivation, MAPK/ERK and PI3K/AKT signaling and ROS formation cause astrocyte swelling.  

Science.gov (United States)

Ammonia toxicity is clinically important and biologically poorly understood. We reported previously that 3mM ammonia chloride (ammonia), a relevant concentration for hepatic encephalopathy studies, increases production of endogenous ouabain and activity of Na,K-ATPase in astrocytes. In addition, ammonia-induced upregulation of gene expression of ?2 isoform of Na,K-ATPase in astrocytes could be inhibited by AG1478, an inhibitor of the EGF receptor (EGFR), and by PP1, an inhibitor of Src, but not by GM6001, an inhibitor of metalloproteinase and shedding of growth factor, suggesting the involvement of endogenous ouabain-induced EGF receptor transactivation. In the present cell culture study, we investigated ammonia effects on phosphorylation of EGF receptor and its intracellular signal pathway towards MAPK/ERK1/2 and PI3K/AKT; interaction between EGF receptor, ?1, and ?2 isoforms of Na,K-ATPase, Src, ERK1/2, AKT and caveolin-1; and relevance of these signal pathways for ammonia-induced cell swelling, leading to brain edema, an often fatal complication of ammonia toxicity. We found that (i) ammonia increases EGF receptor phosphorylation at EGFR(845) and EGFR(1068); (ii) ammonia-induced ERK1/2 and AKT phosphorylation depends on the activity of EGF receptor and Src, but not on metalloproteinase; (iii) AKT phosphorylation occurs upstream of ERK1/2 phosphorylation; (iv) ammonia stimulates association between the ?1 Na,K-ATPase isoform, Src, EGF receptor, ERK1/2, AKT and caveolin-1; (v) ammonia-induced ROS production might occur later than EGFR transactivation; (vi) both ammonia induced ERK phosphorylation and ROS production can be abolished by canrenone, an inhibitor of ouabain, and (vii) ammonia-induced cell swelling depends on signaling via the Na,K-ATPase/ouabain/Src/EGF receptor/PI3K-AKT/ERK1/2, but in response to 3mM ammonia it does not appear until after 12h. Based on literature data it is suggested that the delayed appearance of the ammonia-induced swelling at this concentration reflects required ouabain-induced oxidative damage of the ion and water cotransporter NKCC1. This information may provide new therapeutic targets for treatment of hyperammonic brain disorders. PMID:24044899

Dai, Hongliang; Song, Dan; Xu, Junnan; Li, Baoman; Hertz, Leif; Peng, Liang

2013-11-01

62

Reverse electron flow-mediated ROS generation in ischemia-damaged mitochondria: Role of complex I inhibition vs. depolarization of inner mitochondrial membrane  

Science.gov (United States)

Background The reverse electron flow-induced ROS generation (RFIR) is decreased in ischemia-damaged mitochondria. Cardiac ischemia leads to decreased complex I activity and depolarized inner mitochondrial membrane potential (??) that are two key factors to affect the RFIR in isolated mitochondria. We asked if a partial inhibition of complex I activity without alteration of the ?? is able to decrease the RFIR. Methods Cardiac mitochondria were isolated from mouse heart (C57BL/6) with and without ischemia. The rate of H2O2 production from mitochondria was determined using amplex red coupled with horseradish peroxidase. Mitochondria were isolated from the mitochondrial-targeted STAT3 overexpressing mouse (MLS-STAT3E) to clarify the role of partial complex I inhibition in RFIR production. Results The RFIR was decreased in ischemia-damaged mouse heart mitochondria with decreased complex I activity and depolarized ??. However, the RFIR was not altered in the MLS-STAT3E heart mitochondria with complex I defect but without depolarization of the ??. A slight depolarization of the ?? in wild type mitochondria completely eliminated the RFIR. Conclusions The mild uncoupling but not the partially decreased complex I activity contributes to the observed decrease in RFIR in ischemia-damaged mitochondria. General significance The RFIR is less likely to be a key source of cardiac injury during reperfusion. PMID:23747300

Ross, Thomas; Szczepanek, Karol; Bowler, Elizabeth; Hu, Ying; Larner, Andrew; Lesnefsky, Edward J.; Chen, Qun

2015-01-01

63

Granzyme B-induced mitochondrial ROS are required for apoptosis.  

Science.gov (United States)

Caspases and the cytotoxic lymphocyte protease granzyme B (GB) induce reactive oxygen species (ROS) formation, loss of transmembrane potential and mitochondrial outer membrane permeabilization (MOMP). Whether ROS are required for GB-mediated apoptosis and how GB induces ROS is unclear. Here, we found that GB induces cell death in an ROS-dependent manner, independently of caspases and MOMP. GB triggers ROS increase in target cell by directly attacking the mitochondria to cleave NDUFV1, NDUFS1 and NDUFS2 subunits of the NADH: ubiquinone oxidoreductase complex I inside mitochondria. This leads to mitocentric ROS production, loss of complex I and III activity, disorganization of the respiratory chain, impaired mitochondrial respiration and loss of the mitochondrial cristae junctions. Furthermore, we have also found that GB-induced mitocentric ROS are necessary for optimal apoptogenic factor release, rapid DNA fragmentation and lysosomal rupture. Interestingly, scavenging the ROS delays and reduces many of the features of GB-induced death. Consequently, GB-induced ROS significantly promote apoptosis. PMID:25361078

Jacquemin, G; Margiotta, D; Kasahara, A; Bassoy, E Y; Walch, M; Thiery, J; Lieberman, J; Martinvalet, D

2015-04-01

64

Ischemia/reperfusion-induced upregulation of TIGAR in brain is mediated by SP1 and modulated by ROS and hormones involved in glucose metabolism.  

Science.gov (United States)

We previously found that TIGAR (TP53-induced glycolysis and apoptosis regulator) was upregulated in response to ischemia/reperfusion insult in a TP53-independent manner. The present study sought to investigate the regulatory mechanisms of TIGAR upregulation in animal and cellular models of stroke. The animal and cellular models of ischemia/reperfusion were produced by transient middle cerebral artery occlusion and reperfusion (tMCAO/R) and oxygen-glucose deprivation/reoxygenation (OGD/R), respectively. The expression of TIGAR protein in cortical tissues and hippocampal neuronal cell line HT22 cells or primary neurons was determined. Glucose, hormones and hydrogen peroxide (H2O2) were administered to mice via injection into the tail vein or lateral ventricle or directly added into cell culture medium. In mice subjected to tMCAO/R, the blood glucose level rapidly increased, peaking at 0.5?h and then declined. TIGAR protein was also significantly increased and then declined with a delayed time-course. The increase in TIGAR protein was blunted when blood glucose levels were controlled with insulin. However, administering glucose solution to mice or adding glucose to cell culture medium had no effect on TIGAR protein levels. In contrast adrenaline, hydrocortisone, glucagon and H2O2 significantly increased TIGAR protein expression, whereas insulin inhibited TIGAR expression. The transcription factor SP1 was induced by ischemia/reperfusion ahead of TIGAR upregulation. Inhibiting SP1 with mithramycin A or silencing SP1 with siRNA blocked the ischemia-induced TIGAR upregulation. These results suggest that ROS and hormones regulating blood glucose metabolism play a role in ischemia/reperfusion-induced TIGAR upregulation. PMID:25445985

Sun, Meiling; Li, Mei; Huang, Qiao; Han, Feng; Gu, Jin-Hua; Xie, Jiaming; Han, Rong; Qin, Zheng-Hong; Zhou, Zhipeng

2015-01-01

65

Damage of lipopolysaccharides in outer cell membrane and production of ROS-mediated stress within bacteria makes nano zinc oxide a bactericidal agent  

Science.gov (United States)

Zinc oxide nanoparticle (ZNP) has been synthesized by microwave-assisted technique with the aid of a buffer solution. ZNP inhibited the growth of bacterial system Escherichia coli, even its multidrug-resistant counterpart as well. Systematic evaluation reveals that bioavailable crystalline ZNP damages the lipopolysaccharide layer from outer membrane (OM) of E. coli, subsequently damages the OM followed by inner membrane, enters within the cell and generates extensive reactive oxygen species-mediated damage. A series of biochemical, biophysical and molecular techniques have been used to reach the conclusion. We believe this work is expected to enlighten the detailed mode of action study in bacterial system.

Patra, Prasun; Roy, Shuvrodeb; Sarkar, Sampad; Mitra, Shouvik; Pradhan, Saheli; Debnath, Nitai; Goswami, Arunava

2014-12-01

66

Mitochondrial and cytoplasmic ROS have opposing effects on lifespan.  

Science.gov (United States)

Reactive oxygen species (ROS) are highly reactive, oxygen-containing molecules that can cause molecular damage within the cell. While the accumulation of ROS-mediated damage is widely believed to be one of the main causes of aging, ROS also act in signaling pathways. Recent work has demonstrated that increasing levels of superoxide, one form of ROS, through treatment with paraquat, results in increased lifespan. Interestingly, treatment with paraquat robustly increases the already long lifespan of the clk-1 mitochondrial mutant, but not other long-lived mitochondrial mutants such as isp-1 or nuo-6. To genetically dissect the subcellular compartment in which elevated ROS act to increase lifespan, we deleted individual superoxide dismutase (sod) genes in clk-1 mutants, which are sensitized to ROS. We find that only deletion of the primary mitochondrial sod gene, sod-2 results in increased lifespan in clk-1 worms. In contrast, deletion of either of the two cytoplasmic sod genes, sod-1 or sod-5, significantly decreases the lifespan of clk-1 worms. Further, we show that increasing mitochondrial superoxide levels through deletion of sod-2 or treatment with paraquat can still increase lifespan in clk-1;sod-1 double mutants, which live shorter than clk-1 worms. The fact that mitochondrial superoxide can increase lifespan in worms with a detrimental level of cytoplasmic superoxide demonstrates that ROS have a compartment specific effect on lifespan - elevated ROS in the mitochondria acts to increase lifespan, while elevated ROS in the cytoplasm decreases lifespan. This work also suggests that both ROS-dependent and ROS-independent mechanisms contribute to the longevity of clk-1 worms. PMID:25671321

Schaar, Claire E; Dues, Dylan J; Spielbauer, Katie K; Machiela, Emily; Cooper, Jason F; Senchuk, Megan; Hekimi, Siegfried; Van Raamsdonk, Jeremy M

2015-02-01

67

Acteoside suppresses RANKL-mediated osteoclastogenesis by inhibiting c-Fos induction and NF-?B pathway and attenuating ROS production.  

Science.gov (United States)

Numerous studies have reported that inflammatory cytokines are important mediators for osteoclastogenesis, thereby causing excessive bone resorption and osteoporosis. Acteoside, the main active compound of Rehmannia glutinosa, which is used widely in traditional Oriental medicine, has anti-inflammatory and antioxidant potentials. In this study, we found that acteoside markedly inhibited osteoclast differentiation and formation from bone marrow macrophages (BMMs) and RAW264.7 macrophages stimulated by the receptor activator of nuclear factor-kappaB (NF-?B) ligand (RANKL). Acteoside pretreatment also prevented bone resorption by mature osteoclasts in a dose-dependent manner. Acteoside (10 µM) attenuated RANKL-stimulated activation of p38 kinase, extracellular signal-regulated kinases, and c-Jun N-terminal kinase, and also suppressed NF-?B activation by inhibiting phosphorylation of the p65 subunit and the inhibitor ?B?. In addition, RANKL-mediated increases in the expression of c-Fos and nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1) and in the production of tumor necrosis factor-?, interleukin (IL)-1?, and IL-6 were apparently inhibited by acteoside pretreatment. Further, oral acteoside reduced ovariectomy-induced bone loss and inflammatory cytokine production to control levels. Our data suggest that acteoside inhibits osteoclast differentiation and maturation from osteoclastic precursors by suppressing RANKL-induced activation of mitogen-activated protein kinases and transcription factors such as NF-?B, c-Fos, and NFATc1. Collectively, these results suggest that acteoside may act as an anti-resorptive agent to reduce bone loss by blocking osteoclast activation. PMID:24324641

Lee, Seung-Youp; Lee, Keun-Soo; Yi, Sea Hyun; Kook, Sung-Ho; Lee, Jeong-Chae

2013-01-01

68

ROS signalling – Specificity is required  

DEFF Research Database (Denmark)

The production of reactive oxygen species (ROS) increases in plants under stress. ROS can damage cellular components, but they can also act in signal transduction to help the cell counteract the oxidative damage in the stressed compartment. H2O2 may induce a general stress response, but it does not have the required specificity to selectively regulate nuclear genes required for dealing with localized stress, e.g., in chloroplasts or mitochondria. We here argue that peptides deriving from proteolytic breakdown of oxidatively damaged proteins have the requisite specificity to act as secondary ROS messengers and regulate source-specific genes and in this way contribute to retrograde ROS signalling during oxidative stress. (This is a new project funded by FNU) References: Møller, I.M. & Sweetlove, L.J. 2010. ROS signalling – Specificity is required. Trends Plant Sci. 15: 370-374

MØller, Ian Max; Sweetlove, Lee J

2011-01-01

69

A reaction-diffusion model of ROS-induced ROS release in a mitochondrial network.  

Science.gov (United States)

Loss of mitochondrial function is a fundamental determinant of cell injury and death. In heart cells under metabolic stress, we have previously described how the abrupt collapse or oscillation of the mitochondrial energy state is synchronized across the mitochondrial network by local interactions dependent upon reactive oxygen species (ROS). Here, we develop a mathematical model of ROS-induced ROS release (RIRR) based on reaction-diffusion (RD-RIRR) in one- and two-dimensional mitochondrial networks. The nodes of the RD-RIRR network are comprised of models of individual mitochondria that include a mechanism of ROS-dependent oscillation based on the interplay between ROS production, transport, and scavenging; and incorporating the tricarboxylic acid (TCA) cycle, oxidative phosphorylation, and Ca(2+) handling. Local mitochondrial interaction is mediated by superoxide (O2.-) diffusion and the O2.(-)-dependent activation of an inner membrane anion channel (IMAC). In a 2D network composed of 500 mitochondria, model simulations reveal DeltaPsi(m) depolarization waves similar to those observed when isolated guinea pig cardiomyocytes are subjected to a localized laser-flash or antioxidant depletion. The sensitivity of the propagation rate of the depolarization wave to O(2.-) diffusion, production, and scavenging in the reaction-diffusion model is similar to that observed experimentally. In addition, we present novel experimental evidence, obtained in permeabilized cardiomyocytes, confirming that DeltaPsi(m) depolarization is mediated specifically by O2.-). The present work demonstrates that the observed emergent macroscopic properties of the mitochondrial network can be reproduced in a reaction-diffusion model of RIRR. Moreover, the findings have uncovered a novel aspect of the synchronization mechanism, which is that clusters of mitochondria that are oscillating can entrain mitochondria that would otherwise display stable dynamics. The work identifies the fundamental mechanisms leading from the failure of individual organelles to the whole cell, thus it has important implications for understanding cell death during the progression of heart disease. PMID:20126535

Zhou, Lufang; Aon, Miguel A; Almas, Tabish; Cortassa, Sonia; Winslow, Raimond L; O'Rourke, Brian

2010-01-01

70

ROS as key players in plant stress signalling.  

Science.gov (United States)

Reactive oxygen species (ROS) play an integral role as signalling molecules in the regulation of numerous biological processes such as growth, development, and responses to biotic and/or abiotic stimuli in plants. To some extent, various functions of ROS signalling are attributed to differences in the regulatory mechanisms of respiratory burst oxidase homologues (RBOHs) that are involved in a multitude of different signal transduction pathways activated in assorted tissue and cell types under fluctuating environmental conditions. Recent findings revealed that stress responses in plants are mediated by a temporal-spatial coordination between ROS and other signals that rely on production of stress-specific chemicals, compounds, and hormones. In this review we will provide an update of recent findings related to the integration of ROS signals with an array of signalling pathways aimed at regulating different responses in plants. In particular, we will address signals that confer systemic acquired resistance (SAR) or systemic acquired acclimation (SAA) in plants. PMID:24253197

Baxter, Aaron; Mittler, Ron; Suzuki, Nobuhiro

2014-03-01

71

Learning ROS for robotics programming  

CERN Document Server

The book will take an easy-to-follow and engaging tutorial approach, providing a practical and comprehensive way to learn ROS.If you are a robotic enthusiast who wants to learn how to build and program your own robots in an easy-to-develop, maintainable and shareable way, ""Learning ROS for Robotics Programming"" is for you. In order to make the most of the book, you should have some C++ programming background, knowledge of GNU/Linux systems, and computer science in general. No previous background on ROS is required, since this book provides all the skills required. It is also advisable to hav

Martinez, Aaron

2013-01-01

72

Effect of electroacupuncture to prevent selenite-induced cataract in Wistar rats / Efeito da eletro-acupuntura na prevenção da catarata induzida por selenito de sódio em ratos Wistar  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese OBJETIVO: Avaliar o efeito da eletro-acupuntura na prevenção da catarata induzida por selenito de sódio em modelo experimental. MÉTODO: Cinqüenta filhotes de ratos Wistar foram randomizados em 5 grupos: no Grupo 1 (Controle, n=10) nenhum procedimento foi realizado. Grupo 2 (Selenito, n=10), selenito [...] de sódio (30 µmoles/kg) foi injetado por via subcutânea no décimo dia de vida. No Grupo 3 (Anestesia, n=10), filhotes receberam a mesma dose de selenito e sofreram anestesia inalatória com éter etílico durante 10 minutos diariamente por 1 semana. Grupo 4 (eletro-acupuntura, n=10), os animais sofreram os mesmos procedimentos do Grupo 3, porém também receberam eletro-acupuntura (2 Hz, 50 mA) aplicada nos pontos Neiguan (PC 6) e Guangming (GB37) durante o período de anestesia. Grupo 5 (Sham, n=10), os ratos foram submetidos aos mesmos procedimentos que o Grupo 4, porém as agulhas foram aplicadas em pontos falsos. O desenvolvimento da catarata foi avaliado após uma semana por lâmpada de fenda. RESULTADOS: Todos os animais controles (Grupo 1) não desenvolveram catarata. Todos os ratos dos grupos 2, 3 e 5 desenvolveram catarata grave. No Grupo 4 (eletro-acupuntura), 45% dos olhos não desenvolveram catarata e trinta por cento desenvolveram catarata menos grave que aos Grupos 2, 3 e 5. A diferença entre os grupos foi estatisticamente significante (p Abstract in english PURPOSE: To investigate whether electroacupuncture can prevent selenite-induced cataract in an experimental model. METHODS: Fifty Wistar rat pups were randomized into 5 groups of 10 animals: Group 1 (control), no procedure was performed; Group 2 (selenite), sodium selenite (30 micromoles/kg body wei [...] ght) was injected subcutaneously between postpartum days 10 to 12; Group 3 (anesthesia) received the same dose of selenite and underwent ether inhalation anesthesia during 10 minutes daily for one week; Group 4 (electroacupuncture) underwent the same procedure of Group 3, but also receiving electroacupuncture (2 Hz, 50 mA) applied to the Neiguan (PC6) and Guangming (GB37) acupoints during the anesthesia period; and Group 5 (Sham) underwent the same procedures of Group 4, but needles were applied to non-acupoints. The development of cataract was assessed one week later, and its density was graded by slit lamp biomicroscopy. RESULTS: All control rats lenses (Group 1) were clear. Groups 2, 3 and 5 rats developed more severe cataract or complete opacification. In Group 4 (electroacupuncture), 45% of eyes did not develop cataract while thirty per cent developed less severe cataract than Groups 2, 3 and 5. The between-group difference was statistically significant (p

Angelino Julio, Cariello; Fábio Henrique, Casanova; Acácio Alves de Souza, Lima Filho; Yara, Juliano; Angela, Tabosa.

2006-06-01

73

ROS signalling - specificity is required  

DEFF Research Database (Denmark)

Reactive oxygen species (ROS) production increases in plants under stress. ROS can damage cellular components, but they can also act in signal transduction to help the cell counteract the oxidative damage in the stressed compartment. H2O2 might induce a general stress response, but it does not have the required specificity to selectively regulate nuclear genes required for dealing with localized stress, e.g. in chloroplasts or mitochondria. Here we argue that peptides deriving from proteolytic breakdown of oxidatively damaged proteins have the requisite specificity to act as secondary ROS messengers and regulate source-specific genes and in this way contribute to retrograde ROS signalling during oxidative stress. Likewise, unmodified peptides deriving from the breakdown of redundant proteins could help coordinate organellar and nuclear gene expression

MØller, Ian M; Sweetlove, Lee J

2010-01-01

74

Menadione triggers cell death through ROS-dependent mechanisms involving PARP activation without requiring apoptosis  

OpenAIRE

Low levels of reactive oxygen species (ROS) can function as redox-active signaling messengers, whereas high levels of ROS induce cellular damage. Menadione generates ROS through redox cycling, and high concentrations trigger cell death. Previous work suggests that menadione triggers cytochrome c release from mitochondria, while other studies implicate activation of the mitochondrial permeability transition poreas the mediator of cell death. We investigated menadione-induced cell death in gene...

Loor, Gabriel; Kondapalli, Jyothisri; Schriewer, Jacqueline M.; Chandel, Navdeep S.; Vanden Hoek, Terry L.; Schumacker, Paul T.

2010-01-01

75

Mitochondrial ROS regulates cytoskeletal and mitochondrial remodeling to tune cell and tissue dynamics in a model for wound healing.  

Science.gov (United States)

How cues that trigger the wound response result in tissue healing is a question of immense biological and medical importance. Here we uncover roles for mitochondrial reactive oxygen species (mtROS) during Drosophila dorsal closure, a model for wound healing. By using real-time visualization of ROS activity and single-cell perturbation strategies, we demonstrate that stochasticities in ROS generation in the amnioserosa are necessary and sufficient to trigger cell delamination. We identify dose-dependent effects of mtROS on actomyosin and mitochondrial architecture, dynamics, and activity that mediate both stochasticities in cell behavior and the phases of tissue dynamics accompanying dorsal closure. Our results establish that ROS levels tune cell behavior and tissue dynamics qualitatively and quantitatively. They identify a pathway triggered by ROS and mediated by the Rho effector ROCK and its substrates that influences tissue patterning and homeostasis through the coordinate regulation of both mitochondrial morphology and tissue tension. PMID:24486154

Muliyil, Sonia; Narasimha, Maithreyi

2014-02-10

76

Polymorphic ROS scavenging revealed by CCCP in a lizard.  

OpenAIRE

Ingestion of antioxidants has been argued to scavenge circulating reactive molecules (e.g., free radicals), play a part in mate choice (by mediating access to this important resource), and perhaps increase life span. However, recent work has come to question these relationships. We have shown elsewhere in the polychromatic lizard, Ctenophorus pictus, that diet supplementation of carotenoids as antioxidants does not depress circulating natural reactive oxygen species (ROS) levels and leads to ...

Olsson, M.; Wilson, M.; Isaksson, C.; Uller, T.

2009-01-01

77

8-Methly-4-(3-diethylaminopropylamino) pyrimido [4',5';4,5] thieno (2,3-b) quinoline (MDPTQ), a quinoline derivate that causes ROS-mediated apoptosis in leukemia cell lines  

International Nuclear Information System (INIS)

The present study reports the biological activity of 8-methly-4-(3-diethylamino-propylamino) pyrimido [4';5';4,5] thieno (2,3-b) quinoline (MDPTQ), a quinoline derivative structurally related to ellipticine and suggests a possible mechanism through which the compound induces apoptosis in carcinoma cell lines. Out of the 8 cell lines used in the study as representatives of different types of cancer, MDPTQ was found to be effective only against leukemia cell lines (HL-60 and K-562) whereas it had no effect on normal human bone marrow cells (BMC) which were used as controls. Fall mitochondrial membrane potential and increased reactive oxygen species (ROS) were mainly responsible for inducing apoptosis in the two cell lines. Cell death was demonstrated by increase in caspase 3 activity as well as phosphatidyl serine exposure. Pre-incubation with N-acetylcysteine (NAC) reduced the increased ROS and caspase 3 activity as well as phosphatidyl serine exposure. MDPTQ also caused cell cycle arrest in these cell lines. The above study for the first time reports the mode of action of a quinoline derivative, which could be a possible future candidate for leukemia therapy. However, there are lot of questions that need to be answered in terms of signalling pathways and its effects on animal models

78

The role of ethylene and ROS in salinity, heavy metal, and flooding responses in rice  

Science.gov (United States)

Plant growth and developmental processes as well as abiotic and biotic stress adaptations are regulated by small endogenous signaling molecules. Among these, phytohormones such as the gaseous alkene ethylene and reactive oxygen species (ROS) play an important role in mediating numerous specific growth or cell death responses. While apoplastic ROS are generated by plasma membrane-located respiratory burst oxidase homolog proteins, intracellular ROS are produced mainly in electron transfer chains of mitochondria and chloroplasts. Ethylene accumulates in plants due to physical entrapment or by enhanced ethylene biosynthesis. A major crop that must endure high salt and heavy metal concentrations upon flooding in regions of Asia is rice. Ethylene and ROS have been identified as the major signals that mediate salinity, chromium, and flooding stress in rice. This mini review focuses on (i) what is known about ethylene and ROS level control during these abiotic stresses in rice, (ii) how the two signals mediate growth or death processes, and (iii) feedback mechanisms that in turn regulate ethylene and ROS signaling. PMID:25538719

Steffens, Bianka

2014-01-01

79

Synthesis, characterization and ROS-mediated cytotoxic action of novel (S,S)-1,3-propanediamine-N,N'-di-2-(3-cyclohexyl)propanoic acid and corresponding esters.  

Science.gov (United States)

This study involves the synthesis and characterization of novel cyclohexyl 1,3-propanediamine-N,N'-diacetate molecules as well as investigation of their cytotoxic action. New acid 1a was synthesized by reaction between (S)-2-amino-3-cyclohexylpropanoic acid and 1,3-dibromopropane, while the esters (1b-1e) derived from this acid were obtained by reaction of the corresponding absolute alcohol, thionyl chloride and synthesized acid. All compounds were characterized by IR, ESI-MS, ((1)H, (13)C and HSQC) NMR spectroscopy and elemental analysis. The cytotoxic activity of all compounds was tested on several tumour cell lines: human (U251) and rat (C6) glioma, human promyelocytic leukaemia (HL-60), human neuroblastoma (SHSY-5Y) and mouse fibrosarcoma (L929) as well as primary rat astrocytes. The present study reveals potent antitumour activity of novel purely organic compounds (1a-1e), which was most pronounced in human glioma (U251) cells. The esterification is required for the novel compounds' cytotoxic action since the n-butyl ester 1e was the most efficient compound. Importantly, n-butyl ester 1e was more toxic to glioma cells in comparison to rat astrocytes, with 24-h IC50 values lower than those for cisplatin. n-Butyl ester 1e induced production of reactive oxygen species (ROS) and caused an oxidative-stress-derived accumulation of glioma cells in the G0/G1 phase of the cell cycle, as well as caspase activation and DNA fragmentation, suggesting that apoptosis induction plays an important role in the novel compounds' antiglioma action. PMID:24836201

Savi?, Aleksandar; Misirli?-Den?i?, Sonja; Dulovi?, Marija; Mihajlovi?-Lali?, Ljiljana E; Jovanovi?, Maja; Grguri?-Šipka, Sanja; Markovi?, Ivanka; Sabo, Tibor J

2014-06-01

80

Mitochondria-derived ROS bursts disturb Ca2+ cycling and induce abnormal automaticity in guinea pig cardiomyocytes: a theoretical study.  

Science.gov (United States)

Mitochondria are in close proximity to the redox-sensitive sarcoplasmic reticulum (SR) Ca(2+) release [ryanodine receptors (RyRs)] and uptake [Ca(2+)-ATPase (SERCA)] channels. Thus mitochondria-derived reactive oxygen species (mdROS) could play a crucial role in modulating Ca(2+) cycling in the cardiomyocytes. However, whether mdROS-mediated Ca(2+) dysregulation translates to abnormal electrical activities under pathological conditions, and if yes what are the underlying ionic mechanisms, have not been fully elucidated. We hypothesize that pathological mdROS induce Ca(2+) elevation by modulating SR Ca(2+) handling, which activates other Ca(2+) channels and further exacerbates Ca(2+) dysregulation, leading to abnormal action potential (AP). We also propose that the morphologies of elicited AP abnormality rely on the time of mdROS induction, interaction between mitochondria and SR, and intensity of mitochondrial oxidative stress. To test the hypotheses, we developed a multiscale guinea pig cardiomyocyte model that incorporates excitation-contraction coupling, local Ca(2+) control, mitochondrial energetics, and ROS-induced ROS release. This model, for the first time, includes mitochondria-SR microdomain and modulations of mdROS on RyR and SERCA activities. Simulations show that mdROS bursts increase cytosolic Ca(2+) by stimulating RyRs and inhibiting SERCA, which activates the Na(+)/Ca(2+) exchanger, Ca(2+)-sensitive nonspecific cationic channels, and Ca(2+)-induced Ca(2+) release, eliciting abnormal AP. The morphologies of AP abnormality are largely influenced by the time interval among mdROS burst induction and AP firing, dosage and diffusion of mdROS, and SR-mitochondria distance. This study defines the role of mdROS in Ca(2+) overload-mediated cardiac arrhythmogenesis and underscores the importance of considering mitochondrial targets in designing new antiarrhythmic therapies. PMID:25539710

Li, Qince; Su, Di; O'Rourke, Brian; Pogwizd, Steven M; Zhou, Lufang

2015-03-15

81

Plant cell division: ROS homeostasis is required  

OpenAIRE

Accumulated evidence indicates that ROS fluctuations play a critical role in cell division. Dividing plant cells rapidly respond to them. Experimental disturbance of ROS homeostasis affects: tubulin polymerization; PPB, mitotic spindle and phragmoplast assembly; nuclear envelope dynamics; chromosome separation and movement; cell plate formation. Dividing cells mainly accumulate at prophase and delay in passing through the successive cell division stages. Notably, many dividing root cells of t...

Livanos, Pantelis; Apostolakos, Panagiotis; Galatis, Basil

2012-01-01

82

Kult?ros paveldo vadyba Gotlande  

OpenAIRE

Per pastaruosius dvidešimt penkerius metus švediškas kult?ros paveldo vadybos modelis patyr? daugyb? permain?. Po buvusio biurokratinio, hierarchinio ir direktyvinio ?vertinimo dabar iš naujo atrandamas raidos procesas, kuriame d?mesio atsiduria tokie terminai, kaip demokratija, dalyvavimas, žmon?s ir tarptautin? perspektyva. Švedijos bei Europos kontekste tai ne atsitiktinumas, o veikiau Gotlando visuomen?s tendencij? ir bendrosios raidos rezultatas. Švedijos kult?ros pa...

Edlund, Lennart

2005-01-01

83

Natural daucane esters induces apoptosis in leukaemic cells through ROS production.  

Science.gov (United States)

Continuing our research on antiproliferative agents from plants, we extended our interest on further compounds isolated from Ferula communis and Ferulago campestris. One new daucane (DE-20) and one new phenol derivative (PH-3) were isolated and characterized in addition to six daucane, three coumarins and four simple phenolics. The cytotoxic activity was evaluated against a panel of six human tumor cell lines. The derivative DE-17 that resulted moderately active on all the studied cell lines was studied to evaluate its possible mechanism of action. DE-17 was able to induce apoptosis in a time and concentration-dependent manner in SEM and Jurkat cell lines. We observed that DE-17 just after 1h of treatment increased the reactive oxygen species (ROS) production and that the co-incubation of DE-17 with ROS scavengers significantly increased cell viability suggesting that ROS-mediated downstream signaling is essential for the antiproliferative effects of DE-17. At later times of incubation DE-17 induced mitochondrial depolarization, as well as caspase-3 and -9 activation suggesting that apoptosis follow the mitochondrial pathway. Concomitantly to ROS induction, a remarkable decrease of mRNA expression of several antioxidant enzymes and intracellular GSH content was detected in treated cells compared to controls further indicative of oxidative stress. Taken together our results showed for the first time that daucane esters induces apoptotic cell death through a ROS-mediated mechanism in human leukemia cells. PMID:25294094

Dall'Acqua, Stefano; Linardi, Maria Antonella; Bortolozzi, Roberta; Clauser, Maria; Marzocchini, Sara; Maggi, Filippo; Nicoletti, Marcello; Innocenti, Gabbriella; Basso, Giuseppe; Viola, Giampietro

2014-12-01

84

Respiratory burst oxidases: the engines of ROS signaling.  

Science.gov (United States)

Reactive oxygen species (ROS) play a key signal transduction role in cells. They are involved in the regulation of growth, development, responses to environmental stimuli and cell death. The level of ROS in cells is determined by interplay between ROS producing pathways and ROS scavenging mechanisms, part of the ROS gene network of plants. Recent studies identified respiratory burst oxidase homologues (RBOHs) as key signaling nodes in the ROS gene network of plants integrating a multitude of signal transduction pathways with ROS signaling. The ability of RBOHs to integrate calcium signaling and protein phosphorylation with ROS production, coupled with genetic studies demonstrating their involvement in many different biological processes in cells, places RBOHs at the center of the ROS network of cells and demonstrate their important function in plants. PMID:21862390

Suzuki, Nobuhiro; Miller, Gad; Morales, Jorge; Shulaev, Vladimir; Torres, Miguel Angel; Mittler, Ron

2011-12-01

85

RosE represses Std fimbrial expression in Salmonella enterica serotype Typhimurium.  

Science.gov (United States)

The Salmonella enterica serotype Typhimurium (S. typhimurium) genome contains a large repertoire of putative fimbrial operons that remain poorly characterized because they are not expressed in vitro. In this study, insertions that induced expression of the putative stdABCD fimbrial operon were identified from a random bank of transposon mutants by screening with immuno-magnetic particles for ligand expression (SIMPLE). Transposon insertions upstream of csgC and lrhA or within dam, setB and STM4463 (renamed rosE) resulted in expression of StdA and its assembly into fimbrial filaments on the cell surface. RosE is a novel negative regulator of Std fimbrial expression as indicated by its repression of a std::lacZ reporter construct and by binding of the purified protein to a DNA region upstream of the stdA start codon. Expression of Std fimbriae in the rosE mutant resulted in increased attachment of S. typhimurium to human colonic epithelial cell lines (T-84 and CaCo-2). A rosE mutant exhibited a reduced ability to compete with virulent S. typhimurium for colonization of murine organs, while no defect was observed when both competing strains carried a stdAB deletion. These data suggest that a tight control of Std fimbrial expression mediated by RosE is required during host pathogen interaction. PMID:18331470

Chessa, Daniela; Winter, Maria G; Nuccio, Sean-Paul; Tükel, Cagla; Bäumler, Andreas J

2008-05-01

86

Microcystin-LR-caused ROS generation involved in p38 activation and tau hyperphosphorylation in neuroendocrine (PC12) cells.  

Science.gov (United States)

Microcystin-LR (MC-LR), a potent specific hepatotoxin produced by cyanobacteria, has recently been reported to show neurotoxicity. Our previous study demonstrated that MC-LR caused the reorganization of cytoskeleton architectures and hyperphosphorylation of the cytoskeletal-associated proteins tau and HSP27 in neuroendocrine PC12 cell line by direct PP2A inhibition and indirect p38 mitogen-activated protein kinase (MAPK) activation. It has been shown that oxidative stress is extensively associated with MC-LR toxicity, mainly resulting from an excessive production of reactive oxygen species (ROS). However, the mechanisms by which ROS mediates the cytotoxic action of MC-LR are unclear. In the present study, we investigated whether ROS might play a critical role in MC-LR-induced hyperphosphorylation of microtubule-associated protein tau and the activation of the MAPKs in PC12 cell line. The results showed that MC-LR had time- and concentration-dependent effects on ROS generation, p38-MAPK activation and tau phosphorylation. The time-course studies indicated similar biphasic changes in ROS generation and tau hyperphosphorylation, which started to increase within 1 h and reached the maximum level at 3 h followed by a decrease after prolonged treatment. Furthermore, pretreatment with the antioxidants, N-acetylcysteine and vitamin C, significantly decreased MC-LR-induced ROS generation and effectively attenuated p38-MAPK activation as well as tau hyperphosphorylation. Taken together, these findings suggest that ROS generation triggered by MC-LR is a key intracellular event that contributes to an induction of p38-MAPK activation and tau phosphorylation, and that blockade of this ROS-mediated redox-sensitive signal cascades may attenuate the toxic effects of MC-LR. PMID:24142891

Meng, Guanmin; Liu, Jinghui; Lin, Shuyan; Guo, Zonglou; Xu, Lihong

2015-03-01

87

Dexamethasone inhibits the Nox-dependent ROS production via suppression of MKP-1-dependent MAPK pathways in activated microglia  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Nox-2 (also known as gp91phox, a subunit component of NADPH oxidases, generates reactive oxygen species (ROS. Nox-dependent ROS generation and nitric oxide (NO release by microglia have been implicated in a variety of diseases in the central nervous system. Dexamethasone (Dex has been shown to suppress the ROS production, NO release and inflammatory reaction of activated microglial cells. However, the underlying mechanisms remain unclear. Results The present study showed that the increased ROS production and NO release in activated BV-2 microglial cells by LPS were associated with increased expression of Nox-2 and iNOS. Dex suppressed the upregulation of Nox-2 and iNOS, as well as the subsequent ROS production and NO synthesis in activated BV-2 cells. This inhibition caused by Dex appeared to be mediated by upregulation of MAPK phosphatase-1 (MKP-1, which antagonizes the activity of mitogen-activated protein kinases (MAPKs. Dex induced-suppression of Nox-2 and -upregulation of MKP-1 was also evident in the activated microglia from corpus callosum of postnatal rat brains. The overexpression of MKP-1 or inhibition of MAPKs (by specific inhibitors of JNK and p38 MAPKs, were found to downregulate the expression of Nox-2 and iNOS and thereby inhibit the synthesis of ROS and NO in activated BV-2 cells. Moreover, Dex was unable to suppress the LPS-induced synthesis of ROS and NO in BV-2 cells transfected with MKP-1 siRNA. On the other hand, knockdown of Nox-2 in BV-2 cells suppressed the LPS-induced ROS production and NO release. Conclusion In conclusion, it is suggested that downregulation of Nox-2 and overexpression of MKP-1 that regulate ROS and NO may form the potential therapeutic strategy for the treatment of neuroinflammation in neurodegenerative diseases.

Ling Eng-Ang

2011-05-01

88

Sirt3, Mitochondrial ROS, Ageing, and Carcinogenesis  

Directory of Open Access Journals (Sweden)

Full Text Available One fundamental observation in cancer etiology is that the rate of malignancies in any mammalian population increases exponentially as a function of age, suggesting a mechanistic link between the cellular processes governing longevity and carcinogenesis. In addition, it is well established that aberrations in mitochondrial metabolism, as measured by increased reactive oxygen species (ROS, are observed in both aging and cancer. In this regard, genes that impact upon longevity have recently been characterized in S. cerevisiae and C. elegans, and the human homologs include the Sirtuin family of protein deacetylases. Interestingly, three of the seven sirtuin proteins are localized into the mitochondria suggesting a connection between the mitochondrial sirtuins, the free radical theory of aging, and carcinogenesis. Based on these results it has been hypothesized that Sirt3 functions as a mitochondrial fidelity protein whose function governs both aging and carcinogenesis by modulating ROS metabolism. Sirt3 has also now been identified as a genomically expressed, mitochondrial localized tumor suppressor and this review will outline potential relationships between mitochondrial ROS/superoxide levels, aging, and cell phenotypes permissive for estrogen and progesterone receptor positive breast carcinogenesis.

David Gius

2011-09-01

89

TRPs as chemosensors (ROS, RNS, RCS, gasotransmitters).  

Science.gov (United States)

The transient receptor potential (trp) gene superfamily encodes TRP proteins that act as multimodal sensor cation channels for a wide variety of stimuli from outside and inside the cell. Upon chemical or physical stimulation of cells, TRP channels transduce electrical and/or Ca(2+) signals via their cation channel activities. These functional features of TRP channels allow the body to react and adapt to different forms of environmental changes. Indeed, members of one class of TRP channels have emerged as sensors of reactive oxygen species (ROS), reactive nitrogen species (RNS), reactive carbonyl species (RCS), and gaseous messenger molecules including molecular oxygen (O2), hydrogen sulfide (H2S), and carbon dioxide (CO2). Hydrogen peroxide (H2O2), an ROS, triggers the production of ADP-ribose, which binds and activates TRPM2. In addition to TRPM2, TRPC5, TRPV1, and TRPA1 are also activated by H2O2 via modification of cysteine (Cys) free sulfhydryl groups. Nitric oxide (NO), a vasoactive gaseous molecule, regulates TRP channels directly via Cys S-nitrosylation or indirectly via cyclic GMP (cGMP)/protein kinase G (PKG)-dependent phosphorylation. Anoxia induced by O2-glucose deprivation and severe hypoxia activates TRPM7 and TRPC6, respectively, whereas TRPA1 serves as a sensor of mild hypoxia and hyperoxia in vagal and sensory neurons. TRPA1 also detects other gaseous molecules, such as hydrogen sulfide (H2S) and carbon dioxide (CO2). In this review, we highlight our current knowledge of TRP channels as chemosensors for ROS, RNS, RCS, and gaseous molecules and discuss their functional impacts on physiological and pathological events. PMID:24961969

Shimizu, Shunichi; Takahashi, Nobuaki; Mori, Yasuo

2014-01-01

90

PARP-1 hyperactivation and reciprocal elevations in intracellular Ca2+ during ROS-induced nonapoptotic cell death.  

Science.gov (United States)

The generation of reactive oxygen species (ROS) has been implicated in the pathogenesis of renal ischemia/reperfusion injury, and many other pathological conditions. DNA strand breaks caused by ROS lead to the activation of poly(ADP-ribose)polymerase-1 (PARP-1), the excessive activation of which can result in cell death. We have utilized a model in which 2,3,5-tris(glutathion-S-yl)hydroquinone (TGHQ), a nephrotoxic and nephrocarcinogenic metabolite of hydroquinone, causes ROS-dependent cell death in human renal proximal tubule epithelial cells (HK-2), to further elucidate the role of PARP-1 in ROS-dependent cell death. TGHQ-induced ROS generation, DNA strand breaks, hyperactivation of PARP-1, rapid depletion of nicotinamide adenine dinucleotide (NAD), elevations in intracellular Ca(2+) concentrations, and subsequent nonapoptotic cell death in both a PARP- and Ca(2+)-dependent manner. Thus, inhibition of PARP-1 with PJ34 completely blocked TGHQ-mediated accumulation of poly(ADP-ribose) polymers and NAD consumption, and delayed HK-2 cell death. In contrast, chelation of intracellular Ca(2+) with BAPTA completely abrogated TGHQ-induced cell death. Ca(2+) chelation also attenuated PARP-1 hyperactivation. Conversely, inhibition of PARP-1 modulated TGHQ-mediated changes in Ca(2+) homeostasis. Interestingly, PARP-1 hyperactivation was not accompanied by the translocation of apoptosis-inducing factor (AIF) from mitochondria to the nucleus, a process usually associated with PARP-dependent cell death. Thus, pathways coupling PARP-1 hyperactivation to cell death are likely to be context-dependent, and therapeutic strategies designed to target PARP-1 need to recognize such variability. Our studies provide new insights into PARP-1-mediated nonapoptotic cell death, during which PARP-1 hyperactivation and elevations in intracellular Ca(2+) are reciprocally coupled to amplify ROS-induced nonapoptotic cell death. PMID:24752504

Zhang, Fengjiao; Xie, Ruiye; Munoz, Frances M; Lau, Serrine S; Monks, Terrence J

2014-07-01

91

Mitochondrial ROS potentiates indirect activation of the AIM2 inflammasome.  

Science.gov (United States)

Activation of the inflammasome is important for the detection and clearance of cytosolic pathogens. In contrast to avirulent Francisella novicida (Fn), infection with virulent Francisella tularensis ssp tularensis does not trigger activation of the host AIM2 inflammasome. Here we show that differential activation of AIM2 following Francisella infection is due to sensitivity of each isolate to reactive oxygen species (ROS). ROS present at the outset of Fn infection contributes to activation of the AIM2 inflammasome, independent of NLRP3 and NADPH oxidase. Rather, mitochondrial ROS (mROS) is critical for Fn stimulation of the inflammasome. This study represents the first demonstration of the importance of mROS in the activation of the AIM2 inflammasome by bacteria. Our results also demonstrate that bacterial resistance to mROS is a mechanism of virulence for early evasion of detection by the host. PMID:25191316

Crane, Deborah D; Bauler, Timothy J; Wehrly, Tara D; Bosio, Catharine M

2014-01-01

92

Benzoquinone activates the ERK/MAPK signaling pathway via ROS production in HL-60 cells  

International Nuclear Information System (INIS)

Benzene (BZ) is a class I carcinogen and its oxidation to reactive intermediates is a prerequisite of hematoxicity and myelotoxicity. The generated metabolites include hydroquinone, which is further oxidized to the highly reactive 1,4-benzoquinone (BQ) in bone marrow. Therefore, we explored the mechanisms underlying BQ-induced HL-60 cell proliferation by studying the role of BQ-induced reactive oxygen species (ROS) in the activation of the ERK-MAPK signaling pathway. BQ treatment (0.01-30 ?M) showed that doses below 10 ?M did not significantly reduce viability. ROS production after 3 ?M BQ treatment increased threefold; however, catalase addition reduced ROS generation to basal levels. FACS analysis showed that BQ induced a fivefold increase in the proportion of cells in S-phase. We also observed a high proportion of Bromodeoxyuridine (BrdU) stained cells, indicating a higher DNA synthesis rate. BQ also produced rapid and prolonged phosphorylation of ERK1/2 proteins. Simultaneous treatment with catalase or PD98059, a potent MEK protein inhibitor, reduced cell recruitment into the S-phase and also abolished the ERK1/2 protein phosphorylation induced by BQ, suggesting that MEK/ERK is an important pathway involved in BQ-induced ROS mediated proliferation. The prolonged activation of ERK1/2 contributes to explain the increased S-phase cell recruitment and to understand the leukemogenic processes associated with exposure to benzene metabolites. Thus, the possible mechan metabolites. Thus, the possible mechanism by which BQ induce HL-60 cells to enter the cell cycle and proliferate is linked to ROS production and its growth promoting effects by specific activation of regulating genes known to be activated by redox mechanisms

93

Towards Live Programming in ROS with PhaROS and LRP  

OpenAIRE

In traditional robot behavior programming, the edit-compile-simulate-deploy-run cycle creates a large mental disconnect between program creation and eventual robot behavior. This significantly slows down behavior development because there is no immediate mental connection between the program and the resulting behavior. With live programming the development cycle is made extremely tight, realizing such an immediate connection. In our work on programming of ROS robots in a mor...

Estefo?, Pablo; Campusano, Miguel; Fabresse, Luc; Fabry, Johan; Laval, Jannik; Bouraqad, Noury

2014-01-01

94

ROS upregulation during the early phase of retroviral infection plays an important role in viral establishment in the host cell.  

Science.gov (United States)

Recent studies suggest that low levels of reactive oxygen species (ROS) often modulate normal intracellular signalling pathways, determine cell fates and control cell proliferation. We found that infection of astrocytes with the neuropathogenic retrovirus ts1, a mutant of Moloney murine leukemia retrovirus, upregulated ROS at low levels during the early phase of infection. This upregulation of intracellular ROS with downregulation of NADPH levels during the early phase of ts1 infection was a separate event from the upregulation of ROS during the late phase while ts1-mediated cell death occurred. The treatment of apocynin, a potential inhibitor of NADPH oxidase (NOX), inhibited establishment of the ts1 virus in the host cell. These results suggested that ROS generated as a consequence of the activation of NOX may play an important role in the early events of the virus life cycle leading to the establishment of the virus in the host cell. The in vitro results were further supported by an in vivo experiment which showed that the treatment of apocynin decreased viral titre in the ts1-infected mouse brain and increased the lifespan of infected mice. This study provides the first in vitro and in vivo evidence on a mechanism for how ROS are involved in ts1 retrovirus infection and ts1-mediated neurodegenerative disease. Our findings focusing on the early phase of the ts1 retrovirus life cycle could provide a better understanding of retroviral life cycle, which may offer specific therapeutic targets for suppressing viral replication and alleviating neurodegenerative symptoms in a mouse model. PMID:23884362

Kim, Soo Jin; Wong, Paul K Y

2013-10-01

95

X-ROS signaling in heart and skeletal muscle: stretch-dependent local ROS regulates [Ca2+]i  

Science.gov (United States)

X-ROS signaling is a novel redox signaling pathway that links mechanical stress to changes in [Ca2+]i. This pathway is activated rapidly and locally within a muscle cell under physiological conditions, but can also contribute to Ca2+-dependent arrhythmia in heart and to the dystrophic phenotype in heart and skeletal muscle. Upon physiologic cellular stretch, microtubules serve as mechanotransducers to activate NADPH oxidase 2 in the transverse tubules and sarcolemmal membranes to produce reactive oxygen species (ROS). In heart, the ROS acts locally to activate ryanodine receptor Ca2+ release channels in the junctional sarcoplasmic reticulum, increasing the Ca2+ spark rate and “tuning” excitation-contraction coupling. In skeletal muscle, where Ca2+ sparks are not normally observed, the X-ROS signaling process is muted. However in muscular dystrophies, such as Duchenne Muscular Dystrophy and dysferlinopathy, X-ROS signaling operates at a high level and contributes to myopathy. Importantly, Ca2+ permeable stretch-activated channels are activated by X-ROS and contribute to skeletal muscle pathology. Here we review X-ROS signaling and mechanotransduction in striated muscle, and highlight important questions to drive future work on stretch-dependent signaling. We conclude that X-ROS provides an exciting mechanism for the mechanical control of redox and Ca2+ signaling, but much work is needed to establish its contribution to physiologic and pathophysiologic processes in diverse cell systems. PMID:23220288

Prosser, Benjamin L.; Khairallah, Ramzi J.; Ziman, Andrew P.; Ward, Christopher W.; Lederer, W.J.

2013-01-01

96

X-ROS signaling in the heart and skeletal muscle: stretch-dependent local ROS regulates [Ca²?]i.  

Science.gov (United States)

X-ROS signaling is a novel redox signaling pathway that links mechanical stress to changes in [Ca(2+)]i. This pathway is activated rapidly and locally within a muscle cell under physiological conditions, but can also contribute to Ca(2+)-dependent arrhythmia in the heart and to the dystrophic phenotype in the heart and skeletal muscle. Upon physiologic cellular stretch, microtubules serve as mechanotransducers to activate NADPH oxidase 2 in the transverse tubules and sarcolemmal membranes to produce reactive oxygen species (ROS). In the heart, the ROS acts locally to activate ryanodine receptor Ca(2+) release channels in the junctional sarcoplasmic reticulum, increasing the Ca(2+) spark rate and "tuning" excitation-contraction coupling. In the skeletal muscle, where Ca(2+) sparks are not normally observed, the X-ROS signaling process is muted. However in muscular dystrophies, such as Duchenne Muscular Dystrophy and dysferlinopathy, X-ROS signaling operates at a high level and contributes to myopathy. Importantly, Ca(2+) permeable stretch-activated channels are activated by X-ROS and contribute to skeletal muscle pathology. Here we review X-ROS signaling and mechanotransduction in striated muscle, and highlight important questions to drive future work on stretch-dependent signaling. We conclude that X-ROS provides an exciting mechanism for the mechanical control of redox and Ca(2+) signaling, but much work is needed to establish its contribution to physiologic and pathophysiologic processes in diverse cell systems. PMID:23220288

Prosser, Benjamin L; Khairallah, Ramzi J; Ziman, Andrew P; Ward, Christopher W; Lederer, W J

2013-05-01

97

JNK suppression of chemotherapeutic agents-induced ROS confers chemoresistance on pancreatic cancer stem cells  

Science.gov (United States)

Chemoresistance associated with cancer stem cells (CSCs), which is now being held responsible for the pervasive therapy resistance of pancreatic cancer, poses a major challenge to the successful management of this devastating malignancy. However, the molecular mechanism underlying the marked chemoresistance of pancreatic CSCs remains largely unknown. Here we show that JNK, which is upregulated in pancreatic CSCs and contributes to their maintenance, is critically involved in the resistance of pancreatic CSCs to 5-fluorouracil (5-FU) and gemcitabine (GEM). We found that JNK inhibition effectively sensitizes otherwise chemoresistant pancreatic CSCs to 5-FU and GEM. Significantly, JNK inhibition promoted 5-FU- and GEM-induced increase in intracellular reactive oxygen species (ROS), and scavenging intracellular ROS by use of N-acetylcysteine impaired JNK inhibition-mediated promotion of the cytotoxicity of 5-FU and GEM. Our findings thus suggest that JNK may contribute to the chemoresistance of pancreatic CSCs through prevention of chemotherapeutic agents-induced increase in intracellular ROS. Our findings also suggest that JNK inhibition combined with 5-FU- and/or GEM-based regimens may be a rational therapeutic approach to effectively eliminate pancreatic CSCs. PMID:25473894

Shibuya, Keita; Seino, Manabu; Sato, Atsushi; Takeda, Hiroyuki; Seino, Shizuka; Yoshioka, Takashi; Kitanaka, Chifumi

2015-01-01

98

Adjudin protects rodent cochlear hair cells against gentamicin ototoxicity via the SIRT3-ROS pathway.  

Science.gov (United States)

Hearing loss resulting from hair cell degeneration is a common disease that affects millions of people worldwide. Strategies to overcome the apparent irreversible hair cell loss in mammals become paramount for hearing protection. Here we reported that, by using a well-established gentamicin-induced hair cell loss model in vitro, adjudin, a multi-functional small molecule drug, protected cochlear hair cells from gentamicin damage. Immunohistochemistry, Western blotting and quantitative RT-PCR analyses revealed that adjudin exerted its otoprotective effects by up-regulating the level of Sirt3, a member of Sirtuin family protein located in mitochondria, which regulates reactive oxygen species (ROS) production in cochlear cells and inhibits the production of ROS and apoptotic cells induced by gentamicin. Sirt3 silencing experiments confirmed that Sirt3-ROS signaling axis mediated hair cell protection against gentamicin by adjudin, at least in part. Furthermore, adjudin's otoprotection effects were also observed in an in vivo gentamicin-injured animal model. Taken together, these findings identify adjudin as a novel otoprotective small molecule via elevating Sirt3 levels and Sirt3 may be of therapeutic value in hair cell protection from ototoxic insults. PMID:25640330

Quan, Yizhou; Xia, Li; Shao, Jiaxiang; Yin, Shankai; Cheng, C Yan; Xia, Weiliang; Gao, Wei-Qiang

2015-01-01

99

Modulation of intracellular ROS levels by TIGAR controls autophagy.  

Science.gov (United States)

The p53-inducible TIGAR protein functions as a fructose-2,6-bisphosphatase, promoting the pentose phosphate pathway and helping to lower intracellular reactive oxygen species (ROS). ROS functions in the regulation of many cellular responses, including autophagy--a response to stress conditions such as nutrient starvation and metabolic stress. In this study, we show that TIGAR can modulate ROS in response to nutrient starvation or metabolic stress, and functions to inhibit autophagy. The ability of TIGAR to limit autophagy correlates strongly with the suppression of ROS, with no clear effects on the mTOR pathway, and is p53 independent. The induction of autophagy in response to loss of TIGAR can function to moderate apoptotic response by restraining ROS levels. These results reveal a complex interplay in the regulation of ROS, autophagy and apoptosis in response to TIGAR expression, and shows that proteins similar to TIGAR that regulate glycolysis can have a profound effect on the autophagic response through ROS regulation. PMID:19713938

Bensaad, Karim; Cheung, Eric C; Vousden, Karen H

2009-10-01

100

MaROS: Information Management Service  

Science.gov (United States)

This software is provided by the Mars Relay Operations Service (MaROS) task to a variety of Mars projects for the purpose of coordinating communications sessions between landed spacecraft assets and orbiting spacecraft assets at Mars. The Information Management Service centralizes a set of functions previously distributed across multiple spacecraft operations teams, and as such, greatly improves visibility into the end-to-end strategic coordination process. Most of the process revolves around the scheduling of communications sessions between the spacecraft during periods of time when a landed asset on Mars is geometrically visible by an orbiting spacecraft. These relay sessions are used to transfer data both to and from the landed asset via the orbiting asset on behalf of Earth-based spacecraft operators. This software component is an application process running as a Java virtual machine. The component provides all service interfaces via a Representational State Transfer (REST) protocol over https to external clients. There are two general interaction modes with the service: upload and download of data. For data upload, the service must execute logic specific to the upload data type and trigger any applicable calculations including pass delivery latencies and overflight conflicts. For data download, the software must retrieve and correlate requested information and deliver to the requesting client. The provision of this service enables several key advancements over legacy processes and systems. For one, this service represents the first time that end-to-end relay information is correlated into a single shared repository. The software also provides the first multimission latency calculator; previous latency calculations had been performed on a mission-by-mission basis.

Allard, Daniel A.; Gladden, Roy E.; Wright, Jesse J.; Hy, Franklin H.; Rabideau, Gregg R.; Wallick, Michael N.

2011-01-01

101

Sonodynamic therapy induces the interplay between apoptosis and autophagy in K562 cells through ROS.  

Science.gov (United States)

Sonodynamic therapy (SDT) is a relatively new approach in the treatment of various cancers including leukemia cells. The aim of this study is to investigate the occurrence of apoptosis and autophagy after treated by protoporphyrin IX (PpIX)-mediated SDT (PpIX-SDT) on human leukemia K562 cells as well as the relationship between them. Firstly, mitochondrial-dependent apoptosis was observed through morphological observation and biochemical analysis. Meanwhile, SDT was shown to induce autophagy in K562 cells, which caused an increase in EGFP-LC3 puncta cells, a conversion of LC3 II/I, formation of acidic vesicular organelles (AVOs) and co-localization between LC3 and LAMP2 (a lysosome marker). Besides, pretreatment with autophagy inhibitor 3-MA or bafilomycin A1 was shown to provide protection against autophagy and to enhance SDT-induced apoptosis and necrosis, while the apoptosis suppressor z-VAD-fmk failed to affect formation of autophagic vacuoles or partially prevented SDT-induced cytotoxicity, which suggested that SDT-induced autophagy functioned as a survival mechanism. Additionally, this study reported apparent apoptosis and autophagy with dependence on intracellular reactive oxygen species (ROS) production. Preliminary data showed that ROS scavenger N-acetylcysteine (NAC) effectively blocked the SDT induced accumulation of ROS, reversed sono-damage, cell apoptosis and autophagy. Taken together, these data indicate that autophagy may be cytoprotective in our experimental system, and the ROS caused by PpIX-SDT treatment may play an important role in initiating apoptosis and autophagy. PMID:25578562

Su, Xiaomin; Wang, Pan; Yang, Shuang; Zhang, Kun; Liu, Quanhong; Wang, Xiaobing

2015-03-01

102

PF-06463922 is a potent and selective next-generation ROS1/ALK inhibitor capable of blocking crizotinib-resistant ROS1 mutations.  

Science.gov (United States)

Oncogenic c-ros oncogene1 (ROS1) fusion kinases have been identified in a variety of human cancers and are attractive targets for cancer therapy. The MET/ALK/ROS1 inhibitor crizotinib (Xalkori, PF-02341066) has demonstrated promising clinical activity in ROS1 fusion-positive non-small cell lung cancer. However, emerging clinical evidence has shown that patients can develop resistance by acquiring secondary point mutations in ROS1 kinase. In this study we characterized the ROS1 activity of PF-06463922, a novel, orally available, CNS-penetrant, ATP-competitive small-molecule inhibitor of ALK/ROS1. In vitro, PF-06463922 exhibited subnanomolar cellular potency against oncogenic ROS1 fusions and inhibited the crizotinib-refractory ROS1(G2032R) mutation and the ROS1(G2026M) gatekeeper mutation. Compared with crizotinib and the second-generation ALK/ROS1 inhibitors ceritinib and alectinib, PF-06463922 showed significantly improved inhibitory activity against ROS1 kinase. A crystal structure of the PF-06463922-ROS1 kinase complex revealed favorable interactions contributing to the high-affinity binding. In vivo, PF-06463922 showed marked antitumor activity in tumor models expressing FIG-ROS1, CD74-ROS1, and the CD74-ROS1(G2032R) mutation. Furthermore, PF-06463922 demonstrated antitumor activity in a genetically engineered mouse model of FIG-ROS1 glioblastoma. Taken together, our results indicate that PF-06463922 has potential for treating ROS1 fusion-positive cancers, including those requiring agents with CNS-penetrating properties, as well as for overcoming crizotinib resistance driven by ROS1 mutation. PMID:25733882

Zou, Helen Y; Li, Qiuhua; Engstrom, Lars D; West, Melissa; Appleman, Vicky; Wong, Katy A; McTigue, Michele; Deng, Ya-Li; Liu, Wei; Brooun, Alexei; Timofeevski, Sergei; McDonnell, Scott R P; Jiang, Ping; Falk, Matthew D; Lappin, Patrick B; Affolter, Timothy; Nichols, Tim; Hu, Wenyue; Lam, Justine; Johnson, Ted W; Smeal, Tod; Charest, Al; Fantin, Valeria R

2015-03-17

103

Rac2-MRC-cIII–generated ROS cause genomic instability in chronic myeloid leukemia stem cells and primitive progenitors  

Science.gov (United States)

Chronic myeloid leukemia in chronic phase (CML-CP) is induced by BCR-ABL1 oncogenic tyrosine kinase. Tyrosine kinase inhibitors eliminate the bulk of CML-CP cells, but fail to eradicate leukemia stem cells (LSCs) and leukemia progenitor cells (LPCs) displaying innate and acquired resistance, respectively. These cells may accumulate genomic instability, leading to disease relapse and/or malignant progression to a fatal blast phase. In the present study, we show that Rac2 GTPase alters mitochondrial membrane potential and electron flow through the mitochondrial respiratory chain complex III (MRC-cIII), thereby generating high levels of reactive oxygen species (ROS) in CML-CP LSCs and primitive LPCs. MRC-cIII–generated ROS promote oxidative DNA damage to trigger genomic instability, resulting in an accumulation of chromosomal aberrations and tyrosine kinase inhibitor–resistant BCR-ABL1 mutants. JAK2(V617F) and FLT3(ITD)–positive polycythemia vera cells and acute myeloid leukemia cells also produce ROS via MRC-cIII. In the present study, inhibition of Rac2 by genetic deletion or a small-molecule inhibitor and down-regulation of mitochondrial ROS by disruption of MRC-cIII, expression of mitochondria-targeted catalase, or addition of ROS-scavenging mitochondria-targeted peptide aptamer reduced genomic instability. We postulate that the Rac2-MRC-cIII pathway triggers ROS-mediated genomic instability in LSCs and primitive LPCs, which could be targeted to prevent the relapse and malignant progression of CML. PMID:22411871

Nieborowska-Skorska, Margaret; Kopinski, Piotr K.; Ray, Regina; Hoser, Grazyna; Ngaba, Danielle; Flis, Sylwia; Cramer, Kimberly; Reddy, Mamatha M.; Koptyra, Mateusz; Penserga, Tyrone; Glodkowska-Mrowka, Eliza; Bolton, Elisabeth; Holyoake, Tessa L.; Eaves, Connie J.; Cerny-Reiterer, Sabine; Valent, Peter; Hochhaus, Andreas; Hughes, Timothy P.; van der Kuip, Heiko; Sattler, Martin; Wiktor-Jedrzejczak, Wieslaw; Richardson, Christine; Dorrance, Adrienne; Stoklosa, Tomasz; Williams, David A.

2012-01-01

104

Rac2-MRC-cIII-generated ROS cause genomic instability in chronic myeloid leukemia stem cells and primitive progenitors.  

Science.gov (United States)

Chronic myeloid leukemia in chronic phase (CML-CP) is induced by BCR-ABL1 oncogenic tyrosine kinase. Tyrosine kinase inhibitors eliminate the bulk of CML-CP cells, but fail to eradicate leukemia stem cells (LSCs) and leukemia progenitor cells (LPCs) displaying innate and acquired resistance, respectively. These cells may accumulate genomic instability, leading to disease relapse and/or malignant progression to a fatal blast phase. In the present study, we show that Rac2 GTPase alters mitochondrial membrane potential and electron flow through the mitochondrial respiratory chain complex III (MRC-cIII), thereby generating high levels of reactive oxygen species (ROS) in CML-CP LSCs and primitive LPCs. MRC-cIII-generated ROS promote oxidative DNA damage to trigger genomic instability, resulting in an accumulation of chromosomal aberrations and tyrosine kinase inhibitor-resistant BCR-ABL1 mutants. JAK2(V617F) and FLT3(ITD)-positive polycythemia vera cells and acute myeloid leukemia cells also produce ROS via MRC-cIII. In the present study, inhibition of Rac2 by genetic deletion or a small-molecule inhibitor and down-regulation of mitochondrial ROS by disruption of MRC-cIII, expression of mitochondria-targeted catalase, or addition of ROS-scavenging mitochondria-targeted peptide aptamer reduced genomic instability. We postulate that the Rac2-MRC-cIII pathway triggers ROS-mediated genomic instability in LSCs and primitive LPCs, which could be targeted to prevent the relapse and malignant progression of CML. PMID:22411871

Nieborowska-Skorska, Margaret; Kopinski, Piotr K; Ray, Regina; Hoser, Grazyna; Ngaba, Danielle; Flis, Sylwia; Cramer, Kimberly; Reddy, Mamatha M; Koptyra, Mateusz; Penserga, Tyrone; Glodkowska-Mrowka, Eliza; Bolton, Elisabeth; Holyoake, Tessa L; Eaves, Connie J; Cerny-Reiterer, Sabine; Valent, Peter; Hochhaus, Andreas; Hughes, Timothy P; van der Kuip, Heiko; Sattler, Martin; Wiktor-Jedrzejczak, Wieslaw; Richardson, Christine; Dorrance, Adrienne; Stoklosa, Tomasz; Williams, David A; Skorski, Tomasz

2012-05-01

105

Philip Glass, Scott Walker ja Sigur Ros! / Immo Mihkelson  

Index Scriptorium Estoniae

Pimedate Ööde 11. filmifestivali muusikafilme - Austraalia "Glass: Philipi portree 12 osas" (rež. Scott Hicks), Islandi "Sigur Ros kodus" (rež. Dean DeBois), Suurbritannia "Scott Walker: 30 Century Man" (rež. Stephen Kijak)

Mihkelson, Immo, 1959-

2007-01-01

106

Molecular Pathways - ROS1 Fusion Proteins in Cancer  

Science.gov (United States)

Genetic alterations that lead to constitutive activation of kinases are frequently observed in cancer. In many cases, the growth and survival of tumor cells relies upon an activated kinase such that inhibition of its activity is an effective anti-cancer therapy. ROS1 is a receptor tyrosine kinase that has recently been demonstrated to undergo genetic rearrangements in a variety of human cancers including glioblastoma, non-small cell lung cancer (NSCLC), cholangiocarcinoma, ovarian cancer, gastric adenocarcinoma, colorectal cancer, inflammatory myofibroblastic tumor, angiosarcoma, and epithelioid hemangioendothelioma. These rearrangements create fusion proteins in which the kinase domain of ROS1 becomes constitutively active and drives cellular proliferation. Targeting ROS1 fusion proteins with the small molecule inhibitor crizotinib is showing promise as an effective therapy in NSCLC patients whose tumors are positive for these genetic abnormalities. This review will discuss the recent preclinical and clinical findings on ROS1 gene fusions in cancer. PMID:23719267

Davies, Kurtis D.; Doebele, Robert C.

2013-01-01

107

PERK is required at the ER-mitochondrial contact sites to convey apoptosis after ROS-based ER stress  

OpenAIRE

Endoplasmic reticulum stress is emerging as an important modulator of different pathologies and as a mechanism contributing to cancer cell death in response to therapeutic agents. In several instances, oxidative stress and the onset of endoplasmic reticulum (ER) stress occur together; yet, the molecular events linking reactive oxygen species (ROS) to ER stress-mediated apoptosis are currently unknown. Here, we show that PERK (RNA-dependent protein kinase (PKR)-like ER kinase), a key ER stress...

Verfaillie, T.; Rubio, N.; Garg, A. D.; Bultynck, G.; Rizzuto, R.; Decuypere, J-p; Piette, J.; Linehan, C.; Gupta, S.; Samali, A.; Agostinis, P.

2012-01-01

108

Mitochondrial ROS potentiates indirect activation of the AIM2 inflammasome  

OpenAIRE

Activation of the inflammasome is important for the detection and clearance of cytosolic pathogens. In contrast to avirulent Francisella novicida (Fn), infection with virulent Francisella tularensis ssp tularensis does not trigger activation of the host AIM2 inflammasome. Here we show that differential activation of AIM2 following Francisella infection is due to sensitivity of each isolate to reactive oxygen species (ROS). ROS present at the outset of Fn infection contributes to activation of...

CatharineBosio

2014-01-01

109

Differential responses of pancreatic ?-cells to ROS and RNS  

OpenAIRE

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) direct the activation of distinct signaling pathways that determine cell fate. In this study, the pathways activated and the mechanisms by which ROS and RNS control the viability of pancreatic ?-cells were examined. Although both nitric oxide and hydrogen peroxide (H2O2) induce DNA damage, reduce cell viability, and activate AMPK, the mechanisms of AMPK activation and cell death induction differ between each reactive species. ...

Meares, Gordon P.; Fontanilla, Dominique; Broniowska, Katarzyna A.; Andreone, Teresa; Lancaster, Jack R.; Corbett, John A.

2013-01-01

110

The interplay between ROS and tubulin cytoskeleton in plants  

OpenAIRE

Plants have to deal with reactive oxygen species (ROS) production, since it could potentially cause severe damages to different cellular components. On the other hand, ROS functioning as important second messengers are implicated in various developmental processes and are transiently produced during biotic or abiotic stresses. Furthermore, the microtubules (MTs) play a primary role in plant development and appear as potent players in sensing stressful situations and in the subsequent cellular...

Livanos, Pantelis; Galatis, Basil; Apostolakos, Panagiotis

2014-01-01

111

Darb? grafik? sveikatos prieži?ros ?staigose optimizavimas  

OpenAIRE

Disertacijoje nagrin?jamas sveikatos prieži?ros ?staigos darbuotoj? darb? grafik? optimizavimo uždavinys, kuris formuluojamas ir sprendžiamas, remiantis vienos didžiausi? Lietuvos sveikatos prieži?ros ?staig?, realiais duomenimis. Disertacijoje apžvelgiami darb? grafik? optimizavimo uždaviniai bei j? sprendimo metodai. Pateikiama nagrin?jamo darb? grafik? vienakriterio ir daugiakriterio optimizavimo uždavini? matematin?s formuluot?s. Aprašomos s?lygos, kurias turi...

Liogys, Mindaugas

2013-01-01

112

Aged Garlic Extract Reduces ROS Production and Cell Death Induced by 6-Hydroxydopamine through Activation of the Nrf2-ARE Pathway in SH-SY5Y Cells  

Directory of Open Access Journals (Sweden)

Full Text Available Many degenerative or pathological processes, such as aging, cancer and coronary heart disease, are related to reactive oxygen species (ROS and radical-mediated reactions. We examined the effectiveness of aged garlic extract (AGE, a garlic preparation rich in water-soluble cysteinyl moieties, for protection of cells from ROS produced by 6-hydroxy-dopamine (6-OHDA using human neuroblastoma SH-SY5Y cells. Concomitant treatment of cells with AGE (2 and 4 mg/ml showed the dose-dependent protective effect on the cell death induced by 6-OHDA. In addition, the AGE treatment significantly suppressed the increase of ROS generation by 6-OHDA. Furthermore, the protective effect of AGE was accompanied by activation of the nuclear factor erythroid 2-related factor 2 (Nrf2-antioxidant response element (ARE pathway and the increase of mRNAs of heme oxygenase-1 and NAD(PH quinone oxidoreductase 1. These two enzymes are important in the cellular antioxidant system. These results indicated that AGE protected cells from ROS damage by not only capturing ROS directly but also activating the cellular antioxidant system by stimulating antioxidant gene expression via the Nrf2-ARE pathway. The present study suggested that AGE may be useful for prevention and treatment of cell damage caused by ROS.

Tomoko Fukuuchi

2013-01-01

113

Induction of apoptosis and antiproliferative activity of naringenin in human epidermoid carcinoma cell through ROS generation and cell cycle arrest.  

Science.gov (United States)

A natural predominant flavanone naringenin, especially abundant in citrus fruits, has a wide range of pharmacological activities. The search for antiproliferative agents that reduce skin carcinoma is a task of great importance. The objective of this study was to analyze the anti-proliferative and apoptotic mechanism of naringenin using MTT assay, DNA fragmentation, nuclear condensation, change in mitochondrial membrane potential, cell cycle kinetics and caspase-3 as biomarkers and to investigate the ability to induce reactive oxygen species (ROS) initiating apoptotic cascade in human epidermoid carcinoma A431 cells. Results showed that naringenin exposure significantly reduced the cell viability of A431 cells (p<0.01) with a concomitant increase in nuclear condensation and DNA fragmentation in a dose dependent manner. The intracellular ROS generation assay showed statistically significant (p<0.001) dose-related increment in ROS production for naringenin. It also caused naringenin-mediated epidermoid carcinoma apoptosis by inducing mitochondrial depolarization. Cell cycle study showed that naringenin induced cell cycle arrest in G0/G1 phase of cell cycle and caspase-3 analysis revealed a dose dependent increment in caspase-3 activity which led to cell apoptosis. This study confirms the efficacy of naringenin that lead to cell death in epidermoid carcinoma cells via inducing ROS generation, mitochondrial depolarization, nuclear condensation, DNA fragmentation, cell cycle arrest in G0/G1 phase and caspase-3 activation. PMID:25330158

Ahamad, Md Sultan; Siddiqui, Sahabjada; Jafri, Asif; Ahmad, Sheeba; Afzal, Mohammad; Arshad, Md

2014-01-01

114

ROS and ABA signaling are involved in the growth stimulation induced by low-dose gamma irradiation in Arabidopsis seedling.  

Science.gov (United States)

It has been well established that gamma rays at low doses have stimulatory effects on plant growth and development. However, our knowledge regarding the molecular mechanism underlying the growth stimulation remains limited. In this study, we report the role of reactive oxygen species (ROS) and abscisic acid (ABA) in the growth stimulation using irradiated Arabidopsis seeds. The results indicated that 50 Gy gamma irradiation presented maximal beneficial effects on germination index, root length, and fresh weight. The contents of hydrogen peroxide (H2O2) and activities of antioxidant enzymes under gamma irradiation were markedly higher than those of controls. ROS scavenging significantly suppressed the growth of the irradiated plants. Furthermore, endogenous ABA was induced under low-dose gamma irradiation. The growth stimulation and elevated H2O2 level were affected in the irradiated ABA-deficient mutant aba2-1 compared with the mutant control. Transcriptional expression analysis of selected genes revealed that several genes for ABA biosynthesis were upregulated, and the genes for ABA catabolic pathway and transport were differentially regulated in response to low-dose gamma irradiation. Our results suggest that ROS and ABA signaling play an essential role in the stimulatory effects of low-dose gamma irradiation and that ROS, as secondary molecules, mediate ABA signal transduction under irradiation in response to stress factors during plant growth. PMID:25410801

Qi, Wencai; Zhang, Liang; Feng, Weisen; Xu, Hangbo; Wang, Lin; Jiao, Zhen

2015-02-01

115

Hesperetin induces apoptosis in breast carcinoma by triggering accumulation of ROS and activation of ASK1/JNK pathway.  

Science.gov (United States)

Hesperetin, a flavanone glycoside predominantly found in citrus fruits, exhibits a wide array of biological properties. In the present study hesperetin exhibited a significant cytotoxic effect in human breast carcinoma MCF-7 cells in a concentration- and time-dependent manner without affecting normal (HMEC) as well as immortalized normal mammary epithelial cells (MCF-10A). The cytotoxic effect of hesperetin was due to the induction of apoptosis as evident from the phosphatidyl-serine externalization, DNA fragmentation, caspase-7 activation and PARP cleavage. Apoptosis was associated with caspase-9 activation, mitochondrial membrane potential loss, release of cytochrome c and increase in Bax:Bcl-2 ratio. Pre-treatment with caspase-9 specific inhibitor (Z-LEHD-fmk) markedly attenuated apoptosis suggesting an involvement of intrinsic mitochondrial apoptotic cascade. Further, DCFDA flow-cytometric analysis revealed triggering of ROS in a time-dependent manner. Pre-treatment with ROS scavenger N-acetylcysteine (NAC) and glutathione markedly abrogated hesperetin-mediated apoptosis whereas carbonyl cyanide m-chlorophenylhydrazone (CCCP) pretreatment along with DHR123-based flow-cytometry indicated the generation of cytosolic ROS. Profiling of MAPKs revealed activation of JNK upon hesperetin treatment which was abrogated upon NAC pretreatment. Additionally, inhibition of JNK by SP600125 significantly reversed hesperetinmediated apoptosis. The activation of JNK was associated with the activation of ASK1. Silencing of ASK1 resulted in significant attenuation of JNK activation as well as reversed the hesperetin-mediated apoptosis suggesting that hesperetin-mediated apoptosis of MCF-7 cells involves accumulation of ROS and activation of ASK1/JNK pathway. In addition, hesperetin also induced apoptosis in triple negative breast cancer MDA-MB-231 cells via intrinsic pathway via activation of caspase -9 and -3 and increase in Bax:Bcl-2 ratio. J. Cell. Physiol. © 2014 Wiley Periodicals, Inc. PMID:25204891

Palit, Shreyasi; Kar, Susanta; Sharma, Gunjan; Das, Pijush K

2014-09-10

116

Overexpression of Smad7 suppressed ROS/MMP9-dependent collagen synthesis through regulation of heme oxygenase-1.  

Science.gov (United States)

We previously reported that AngiotensinII receptor blocker effectively inhibited TGF-?1-mediated epithelial-to-mesenchymal transition progress through regulating Smad7. However, the underlying mechanism by which Smad7 exerted in regulating MMP9 and fibrogenic response has not been fully elucidated. In the current study, we proved that NADPH p47(phox)-dependent reactive oxygen species (ROS) production contributed to MMP9 activation and collagen expression, which was suppressed by transfecting pcDNA3-Smad7 in cardiac fibroblasts. The effect of Smad7 overexpression on MMP9 activity and collagen expression was further reversed by adding H2O2 (10 ?mol/L). In contrast, knockdown of Smad7 caused the enhanced collagen synthesis in cardiac fibroblasts, which was also reversed by treating cells with a ROS inhibitor, YCG063 (2 ?mol/L). Further investigation showed that Smad7 regulated NADPH-mediated ROS production through activating Heme oxygenase-1 (HO-1). Meanwhile, the intercellular level of bilirubin (product of hemin) and nitric oxide (NO) in cell supernatant were not significantly increased in cells treated with AngII or transfected with Smad7. Knockdown of HO-1 in Smad7-overexpressed cardiac fibroblasts or cells pretreated with SnPP IX, a competitive inhibitor of HO-1 activity, resulted in increased productions of ROS and NADPH p47(phox), and abolished the inhibitory effects of Smad7 on MMP9 activity and collagen expression. Our results indicated that HO-1 might be critically involved in Smad7-mediated regulation of MMP9 activity and fibrogenic genes expression via antagonizing the enhanced myocardial oxidative stress. PMID:23661026

Yu, Hong; Huang, Junxing; Wang, Shijun; Zhao, Gang; Jiao, Xia; Zhu, Li

2013-09-01

117

The roles of ROS and ABA in systemic acquired acclimation.  

Science.gov (United States)

Systemic responses to environmental stimuli are essential for the survival of multicellular organisms. In plants, they are initiated in response to many different signals including pathogens, wounding, and abiotic stresses. Recent studies highlighted the importance of systemic acquired acclimation to abiotic stresses in plants and identified several different signals involved in this response. These included reactive oxygen species (ROS) and calcium waves, hydraulic waves, electric signals, and abscisic acid (ABA). Here, we address the interactions between ROS and ABA at the local and systemic tissues of plants subjected to abiotic stress and attempt to propose a model for the involvement of ROS, ABA, and stomata in systemic signaling leading to systemic acquired acclimation. PMID:25604442

Mittler, Ron; Blumwald, Eduardo

2015-01-01

118

Ischaemic accumulation of succinate controls reperfusion injury through mitochondrial ROS.  

Science.gov (United States)

Ischaemia-reperfusion injury occurs when the blood supply to an organ is disrupted and then restored, and underlies many disorders, notably heart attack and stroke. While reperfusion of ischaemic tissue is essential for survival, it also initiates oxidative damage, cell death and aberrant immune responses through the generation of mitochondrial reactive oxygen species (ROS). Although mitochondrial ROS production in ischaemia reperfusion is established, it has generally been considered a nonspecific response to reperfusion. Here we develop a comparative in vivo metabolomic analysis, and unexpectedly identify widely conserved metabolic pathways responsible for mitochondrial ROS production during ischaemia reperfusion. We show that selective accumulation of the citric acid cycle intermediate succinate is a universal metabolic signature of ischaemia in a range of tissues and is responsible for mitochondrial ROS production during reperfusion. Ischaemic succinate accumulation arises from reversal of succinate dehydrogenase, which in turn is driven by fumarate overflow from purine nucleotide breakdown and partial reversal of the malate/aspartate shuttle. After reperfusion, the accumulated succinate is rapidly re-oxidized by succinate dehydrogenase, driving extensive ROS generation by reverse electron transport at mitochondrial complex I. Decreasing ischaemic succinate accumulation by pharmacological inhibition is sufficient to ameliorate in vivo ischaemia-reperfusion injury in murine models of heart attack and stroke. Thus, we have identified a conserved metabolic response of tissues to ischaemia and reperfusion that unifies many hitherto unconnected aspects of ischaemia-reperfusion injury. Furthermore, these findings reveal a new pathway for metabolic control of ROS production in vivo, while demonstrating that inhibition of ischaemic succinate accumulation and its oxidation after subsequent reperfusion is a potential therapeutic target to decrease ischaemia-reperfusion injury in a range of pathologies. PMID:25383517

Chouchani, Edward T; Pell, Victoria R; Gaude, Edoardo; Aksentijevi?, Dunja; Sundier, Stephanie Y; Robb, Ellen L; Logan, Angela; Nadtochiy, Sergiy M; Ord, Emily N J; Smith, Anthony C; Eyassu, Filmon; Shirley, Rachel; Hu, Chou-Hui; Dare, Anna J; James, Andrew M; Rogatti, Sebastian; Hartley, Richard C; Eaton, Simon; Costa, Ana S H; Brookes, Paul S; Davidson, Sean M; Duchen, Michael R; Saeb-Parsy, Kourosh; Shattock, Michael J; Robinson, Alan J; Work, Lorraine M; Frezza, Christian; Krieg, Thomas; Murphy, Michael P

2014-11-20

119

Influenza A virus and TLR7 activation potentiate NOX2 oxidase-dependent ROS production in macrophages.  

Science.gov (United States)

Influenza A virus infects resident alveolar macrophages in the respiratory tract resulting in Toll like receptor 7 (TLR7) activation that triggers an inflammatory response to resolve the infection. Macrophages are also major sources of reactive oxygen species (ROS) via the NOX2-containing NADPH oxidase. Although ROS are crucial for pathogen clearance, in response to influenza A virus, ROS are touted as being culprit mediators of the lung tissue injury. The aim of the present study was to determine whether influenza A virus infection and TLR7 activation of macrophages, results in alterations in their ROS production. Here we demonstrate using immunofluorescence that influenza A virus (Hong Kong X-31 strain; H3N2) internalizes in RAW264.7 cells and mouse alveolar macrophages within 1 h, resulting in a significant enhancement in the stimulated NOX2 oxidase-dependent oxidative burst, although virus had no effect on basal ROS. The specific TLR7 agonist imiquimod (10 ?g/ml) elevated basal superoxide production and, in a similar fashion to influenza A virus, enhanced NOX2 oxidase-dependent oxidative burst. By contrast, the TLR3 agonist, poly I:C (1-100 ?g/ml) failed to influence the oxidative burst to NOX2 oxidase. A peptide corresponding to the region 337-348 on p47phox conjugated to a HIV-tat, designed to inhibit the phosphorylation of Ser346 on p47phox suppressed the influenza A virus- and imiquimod-induced enhancement in the oxidative burst. In conclusion, this study demonstrates for the first time that influenza A virus and TLR7 activation enhance the NOX2 oxidase-dependent oxidative burst in macrophages, which might underpin the acute lung injury to influenza A virus infection. PMID:24869957

To, E E; Broughton, B R S; Hendricks, K S; Vlahos, R; Selemidis, S

2014-08-01

120

Cadmium induces carcinogenesis in BEAS-2B cells through ROS-dependent activation of PI3K/AKT/GSK-3?/?-catenin signaling  

Energy Technology Data Exchange (ETDEWEB)

Cadmium has been widely used in industry and is known to be carcinogenic to humans. Although it is widely accepted that chronic exposure to cadmium increases the incidence of cancer, the mechanisms underlying cadmium-induced carcinogenesis are unclear. The main aim of this study was to investigate the role of reactive oxygen species (ROS) in cadmium-induced carcinogenesis and the signal transduction pathways involved. Chronic exposure of human bronchial epithelial BEAS-2B cells to cadmium induced cell transformation, as evidenced by anchorage-independent growth in soft agar and clonogenic assays. Chronic cadmium treatment also increased the potential of these cells to invade and migrate. Injection of cadmium-stimulated cells into nude mice resulted in the formation of tumors. In contrast, the cadmium-mediated increases in colony formation, cell invasion and migration were prevented by transfection with catalase, superoxide dismutase-1 (SOD1), or SOD2. In particular, chronic cadmium exposure led to activation of signaling cascades involving PI3K, AKT, GSK-3?, and ?-catenin and transfection with each of the above antioxidant enzymes markedly inhibited cadmium-mediated activation of these signaling proteins. Inhibitors specific for AKT or ?-catenin almost completely suppressed the cadmium-mediated increase in total and active ?-catenin proteins and colony formation. Moreover, there was a marked induction of AKT, GSK-3?, ?-catenin, and carcinogenic markers in tumor tissues formed in mice after injection with cadmium-stimulated cells. Collectively, our findings suggest a direct involvement of ROS in cadmium-induced carcinogenesis and implicate a role of AKT/GSK-3?/?-catenin signaling in this process. -- Highlights: ? Chronic exposure to cadmium induces carcinogenic properties in BEAS-2B cells. ? ROS involved in cadmium-induced tumorigenicity of BEAS-2B cells. ? Cadmium activates ROS-dependent AKT/GSK-3?/?-catenin-mediated signaling. ? ROS-dependent signaling as potential therapeutic targets in cadmium carcinogenesis.

Son, Young-Ok; Wang, Lei; Poyil, Pratheeshkumar; Budhraja, Amit; Hitron, J. Andrew; Zhang, Zhuo [Graduate Center for Toxicology, College of Medicine, University of Kentucky, Lexington, KY (United States); Lee, Jeong-Chae [Graduate Center for Toxicology, College of Medicine, University of Kentucky, Lexington, KY (United States); School of Dentistry and Institute of Oral Biosciences (BK21 program), Research Center of Bioactive Materials, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Shi, Xianglin, E-mail: xshi5@email.uky.edu [Graduate Center for Toxicology, College of Medicine, University of Kentucky, Lexington, KY (United States)

2012-10-15

121

NADPH oxidase/ROS-dependent PYK2 activation is involved in TNF-?-induced matrix metalloproteinase-9 expression in rat heart-derived H9c2 cells  

International Nuclear Information System (INIS)

TNF-? plays a mediator role in the pathogenesis of chronic heart failure contributing to cardiac remodeling and peripheral vascular disturbances. The implication of TNF-? in inflammatory responses has been shown to be mediated through up-regulation of matrix metalloproteinase-9 (MMP-9). However, the detailed mechanisms of TNF-?-induced MMP-9 expression in rat embryonic-heart derived H9c2 cells are largely not defined. We demonstrated that in H9c2 cells, TNF-? induced MMP-9 mRNA and protein expression associated with an increase in the secretion of pro-MMP-9. TNF-?-mediated responses were attenuated by pretreatment with the inhibitor of ROS (N-acetyl-L-cysteine, NAC), NADPH oxidase [apocynin (APO) or diphenyleneiodonium chloride (DPI)], MEK1/2 (U0126), p38 MAPK (SB202190), JNK1/2 (SP600125), NF-?B (Bay11-7082), or PYK2 (PF-431396) and transfection with siRNA of TNFR1, p47phox, p42, p38, JNK1, p65, or PYK2. Moreover, TNF-? markedly induced NADPH oxidase-derived ROS generation in these cells. TNF-?-enhanced p42/p44 MAPK, p38 MAPK, JNK1/2, and NF-?B (p65) phosphorylation and in vivo binding of p65 to the MMP-9 promoter were inhibited by U0126, SB202190, SP600125, NAC, DPI, or APO. In addition, TNF-?-mediated PYK2 phosphorylation was inhibited by NAC, DPI, or APO. PYK2 inhibition could reduce TNF-?-stimulated MAPKs and NF-?B activation. Thus, in H9c2 cells, we are the first to show that TNF-?-induced MMP-9 expression is mediated through a TNFR1/NADPH oxidase/ROS/PYK2/MAPKs/NF-?B cascade. We demonstrated that NADPH oxidase-derived ROS generation is involved in TNF-?-induced PYK2 activation in these cells. Understanding the regulation of MMP-9 expression and NADPH oxidase activation by TNF-? on H9c2 cells may provide potential therapeutic targets of chronic heart failure. - Highlights: • TNF-? induces MMP-9 secretion and expression via a TNFR1-dependent pathway. • TNF-? induces ROS/PYK2-dependent MMP-9 expression in H9c2 cells. • TNF-? induces MMP-9 expression via a NADPH oxidase/ROS-dependent NF-?B signaling. • TNF-? activates MAPK phosphorylation through NADPH oxidase/ROS generation

122

NADPH oxidase/ROS-dependent PYK2 activation is involved in TNF-?-induced matrix metalloproteinase-9 expression in rat heart-derived H9c2 cells  

Energy Technology Data Exchange (ETDEWEB)

TNF-? plays a mediator role in the pathogenesis of chronic heart failure contributing to cardiac remodeling and peripheral vascular disturbances. The implication of TNF-? in inflammatory responses has been shown to be mediated through up-regulation of matrix metalloproteinase-9 (MMP-9). However, the detailed mechanisms of TNF-?-induced MMP-9 expression in rat embryonic-heart derived H9c2 cells are largely not defined. We demonstrated that in H9c2 cells, TNF-? induced MMP-9 mRNA and protein expression associated with an increase in the secretion of pro-MMP-9. TNF-?-mediated responses were attenuated by pretreatment with the inhibitor of ROS (N-acetyl-L-cysteine, NAC), NADPH oxidase [apocynin (APO) or diphenyleneiodonium chloride (DPI)], MEK1/2 (U0126), p38 MAPK (SB202190), JNK1/2 (SP600125), NF-?B (Bay11-7082), or PYK2 (PF-431396) and transfection with siRNA of TNFR1, p47{sup phox}, p42, p38, JNK1, p65, or PYK2. Moreover, TNF-? markedly induced NADPH oxidase-derived ROS generation in these cells. TNF-?-enhanced p42/p44 MAPK, p38 MAPK, JNK1/2, and NF-?B (p65) phosphorylation and in vivo binding of p65 to the MMP-9 promoter were inhibited by U0126, SB202190, SP600125, NAC, DPI, or APO. In addition, TNF-?-mediated PYK2 phosphorylation was inhibited by NAC, DPI, or APO. PYK2 inhibition could reduce TNF-?-stimulated MAPKs and NF-?B activation. Thus, in H9c2 cells, we are the first to show that TNF-?-induced MMP-9 expression is mediated through a TNFR1/NADPH oxidase/ROS/PYK2/MAPKs/NF-?B cascade. We demonstrated that NADPH oxidase-derived ROS generation is involved in TNF-?-induced PYK2 activation in these cells. Understanding the regulation of MMP-9 expression and NADPH oxidase activation by TNF-? on H9c2 cells may provide potential therapeutic targets of chronic heart failure. - Highlights: • TNF-? induces MMP-9 secretion and expression via a TNFR1-dependent pathway. • TNF-? induces ROS/PYK2-dependent MMP-9 expression in H9c2 cells. • TNF-? induces MMP-9 expression via a NADPH oxidase/ROS-dependent NF-?B signaling. • TNF-? activates MAPK phosphorylation through NADPH oxidase/ROS generation.

Yang, Chuen-Mao, E-mail: chuenmao@mail.cgu.edu.tw [Department of Physiology and Pharmacology and Health Aging Research Center, Chang Gung University, Kwei-San, Tao-Yuan, Taiwan (China); Heart Failure Center, Division of Cardiology, Department of Internal Medicine, Chang Gung Memorial Hospital at Keelung, Keelung, Taiwan (China); Lee, I-Ta [Department of Physiology and Pharmacology and Health Aging Research Center, Chang Gung University, Kwei-San, Tao-Yuan, Taiwan (China); Department of Anesthetics, Chang Gung Memorial Hospital at Linkou and College of Medicine, Chang Gung University, Kwei-San, Tao-Yuan, Taiwan (China); Hsu, Ru-Chun; Chi, Pei-Ling; Hsiao, Li-Der [Department of Physiology and Pharmacology and Health Aging Research Center, Chang Gung University, Kwei-San, Tao-Yuan, Taiwan (China)

2013-10-15

123

ROS-induced autophagy in cancer cells assists in evasion from determinants of immunogenic cell death.  

Science.gov (United States)

Calreticulin surface exposure (ecto-CALR), ATP secretion, maturation of dendritic cells (DCs) and stimulation of T cells are prerequisites for anticancer therapy-induced immunogenic cell death (ICD). Recent evidence suggests that chemotherapy-induced autophagy may positively regulate ICD by favoring ATP secretion. We have recently shown that reactive oxygen species (ROS)-based endoplasmic reticulum (ER) stress triggered by hypericin-mediated photodynamic therapy (Hyp-PDT) induces bona fide ICD. However, whether Hyp-PDT-induced autophagy regulates ICD was not explored. Here we showed that, in contrast to expectations, reducing autophagy (by ATG5 knockdown) in cancer cells did not alter ATP secretion after Hyp-PDT. Autophagy-attenuated cancer cells displayed enhanced ecto-CALR induction following Hyp-PDT, which strongly correlated with their inability to clear oxidatively damaged proteins. Furthermore, autophagy-attenuation in Hyp-PDT-treated cancer cells increased their ability to induce DC maturation, IL6 production and proliferation of CD4(+) or CD8(+) T cells, which was accompanied by IFNG production. Thus, our study unravels a role for ROS-induced autophagy in weakening functional interaction between dying cancer cells and the immune system thereby helping in evasion from ICD prerequisites or determinants. PMID:23800749

Garg, Abhishek D; Dudek, Aleksandra M; Ferreira, Gabriela B; Verfaillie, Tom; Vandenabeele, Peter; Krysko, Dmitri V; Mathieu, Chantal; Agostinis, Patrizia

2013-09-01

124

Neoalbaconol induces cell death through necroptosis by regulating RIPK-dependent autocrine TNF? and ROS production  

Science.gov (United States)

Necroptosis/regulated necrosis is a caspase-independent, but receptor interacting protein kinase (RIPK)-dependent form of cell death. In previous studies, neoalbaconol (NA), a constituent extracted from Albatrellus confluens, was demonstrated to induce necroptosis in some cancer cell lines. The molecular mechanism of NA-induced necroptosis is described in this research study. We determined that NA-induced cell death is partly dependent on tumor necrosis factor ? (TNF?) feed-forward signaling. More importantly, NA abolished the ubiquitination of RIPK1 by down-regulating E3 ubiquitin ligases, cellular inhibitors of apoptosis protein 1/2 (cIAP1/2) and TNF? receptor-associated factors (TRAFs). The suppression of RIPK1 ubiquitination induced the activation of the non-canonical nuclear factor-?B (NF-?B) pathway and stimulated the transcription of TNF?. Moreover, we also found that NA caused RIPK3-mediated reactive oxygen species (ROS) production and contribution to cell death. Taken together, these results suggested that two distinct mechanisms are involved in NA-induced necroptosis and include RIPK1/NF-?B-dependent expression of TNF? and RIPK3-dependent generation of ROS. PMID:25575821

Li, Wei; Xiao, Lanbo; Luo, Xiangjian; Liu, Xiaolan; Yang, Lifang; Peng, Songling; Ding, Zhihui; Feng, Tao; Zhou, Jian; Fan, Jia; Bode, Ann M.; Dong, Zigang; Liu, Jikai; Cao, Ya

2015-01-01

125

Neoalbaconol induces cell death through necroptosis by regulating RIPK-dependent autocrine TNF? and ROS production.  

Science.gov (United States)

Necroptosis/regulated necrosis is a caspase-independent, but receptor interacting protein kinase (RIPK)-dependent form of cell death. In previous studies, neoalbaconol (NA), a constituent extracted from Albatrellus confluens, was demonstrated to induce necroptosis in some cancer cell lines. The molecular mechanism of NA-induced necroptosis is described in this research study. We determined that NA-induced cell death is partly dependent on tumor necrosis factor ? (TNF?) feed-forward signaling. More importantly, NA abolished the ubiquitination of RIPK1 by down-regulating E3 ubiquitin ligases, cellular inhibitors of apoptosis protein 1/2 (cIAP1/2) and TNF? receptor-associated factors (TRAFs). The suppression of RIPK1 ubiquitination induced the activation of the non-canonical nuclear factor-?B (NF-?B) pathway and stimulated the transcription of TNF?. Moreover, we also found that NA caused RIPK3-mediated reactive oxygen species (ROS) production and contribution to cell death. Taken together, these results suggested that two distinct mechanisms are involved in NA-induced necroptosis and include RIPK1/NF-?B-dependent expression of TNF? and RIPK3-dependent generation of ROS. PMID:25575821

Yu, Xinfang; Deng, Qipan; Li, Wei; Xiao, Lanbo; Luo, Xiangjian; Liu, Xiaolan; Yang, Lifang; Peng, Songling; Ding, Zhihui; Feng, Tao; Zhou, Jian; Fan, Jia; Bode, Ann M; Dong, Zigang; Liu, Jikai; Cao, Ya

2015-02-10

126

Using ROS for agricultural robotics : design considerations and experiences  

OpenAIRE

We report on experiences of using the ROS middleware for developmentof agricultural robots. We describe software related design considerations for all maincomponents in developed subsystems as well as drawbacks and advantages with thechosen approaches. This work was partly funded by the European Commission(CROPS GA no 246252).

Barth, Ruud; Baur, Jo?rg; Buschmann, Thomas; Edan, Yael; Hellstro?m, Thomas; Nguyen, Thanh; Ringdahl, Ola; Saeys, Wouter; Salinas, Carlota; Vitzrabin, Efi

2014-01-01

127

Kuula : Sigur Ros rokiklubis. Kammemuusikat Tallinnas. Loomade reekviem  

Index Scriptorium Estoniae

23. aug. esineb Tallinna rokiklubis Rock Café islandi bänd Sigur Ros. Pille Lille muusikute toetusfondi korraldatavast Tallinna Kammermuusika festivalist 17.-23. aug. Tallinna Rootsi Mihkli kirikus, Raekojas ja Jaani kirkus (vt. www.plmf.ee). Kontserdist Nargen Festivali raames 30. ja 31. aug. Tallinna loomaaias

2008-01-01

128

The interplay between autophagy and ROS in tumorigenesis  

Directory of Open Access Journals (Sweden)

Full Text Available Reactive oxygen species (ROS at physiological levels are important cell signaling molecules. However, aberrantly high ROS are intimately associated with disease and commonly observed in cancer. Mitochondria are primary sources of intracellular ROS, and their maintenance is essential to cellular health. Autophagy, an evolutionarily conserved process whereby cytoplasmic components are delivered to lysosomes for degradation, is responsible for mitochondrial turnover and removal of damaged mitochondria. Impaired autophagy is implicated in many pathological conditions, including neurological disorders, inflammatory bowel disease, diabetes, aging and cancer. The first reports connecting autophagy to cancer showed that allelic loss of the essential autophagy gene BECLIN1 (BECN1 is prevalent in human breast, ovarian and prostate cancers and that Becn1+/- mice develop mammary gland hyperplasias, lymphomas, and lung and liver tumors. Subsequent studies demonstrated that Atg5-/- and Atg7-/- livers give rise to adenomas, Atg4-/- mice are susceptible to chemical carcinogenesis, and Bif1-/- mice are prone to spontaneous tumors, indicating that autophagy defects promote tumorigenesis. Due to defective mitophagy, autophagy-deficient cells accumulate damaged mitochondria and deregulated ROS levels, which likely contribute to their tumor-initiating capacity. However, the role of autophagy in tumorigenesis is complex, as more recent work also revealed tumor dependence on autophagy: autophagy-competent mutant-Ras-expressing cells form tumors more efficiently than their autophagy-deficient counterparts; similarly, FIP200 deficiency suppresses PyMT-driven mammary tumorigenesis. These latter findings are attributed to the fact that tumors driven by powerful oncogenes have high metabolic demands catered to by autophagy. In this review, we discuss the relationship between ROS and autophagy and summarize our current knowledge on their functional interactions in tumorigenesis.

VassilikiKarantza

2012-11-01

129

Roles for mannitol and mannitol dehydrogenase in active oxygen-mediated plant defense  

OpenAIRE

Reactive oxygen species (ROS) are both signal molecules and direct participants in plant defense against pathogens. Many fungi synthesize mannitol, a potent quencher of ROS, and there is growing evidence that at least some phytopathogenic fungi use mannitol to suppress ROS-mediated plant defenses. Here we show induction of mannitol production and secretion in the phytopathogenic fungus Alternaria alternata in the presence of host-plant extracts. Conversely, we show that the catabolic enzyme m...

Jennings, Dianne B.; Ehrenshaft, Marilyn; Pharr, D. Mason; Williamson, John D.

1998-01-01

130

Protective effects of andrographolide analogue AL-1 on ROS-induced RIN-m? cell death by inducing ROS generation.  

Science.gov (United States)

Oxidative stress is considered to be a major factor contributing to pathogenesis and progression of many diseases. A novel andrographolide-lipoic acid conjugate (AL-1) could protect pancreatic ?-cells from reactive oxygen species (ROS)-induced oxidative injury. However, its protective mechanism is still unclear. In this work, we used proteomics to identify AL-1-regulated proteins in ?-cells and found that 13 of the 71 proteins regulated by AL-1 were closely associated with antioxidation. These differential proteins were mainly involved in the ERK1/2 and AKT1 signaling pathways. Functional investigation demonstrated that AL-1 exerted its protective effects on H2O2-induced cell death of ?-cells by generating NADPH oxidase-dependent ROS to activate ERK1/2 and AKT1 signaling pathways. As a consequence, the expressions of antioxidant proteins including Trx1, Prx1 and Prx5, and anti-apoptotic proteins including PDCD6IP, prohibitin, galectin-1 and HSP were upregulated. AL-1 probably worked as a "vaccinum" to activate the cellular antioxidant system by inducing the generation of low concentration ROS which then reciprocally protected ?-cells from oxidative damage caused by high-level ROS from H2O2. To the best of our knowledge, this is the first comprehensive proteomic analysis illustrating a novel molecular mechanism for the protective effects of antioxidants on ?-cells from H2O2-induced cell death. PMID:23750203

Yan, Guang-Rong; Zhou, Hui-Hua; Wang, Yang; Zhong, Yin; Tan, Zi-Lu; Wang, Yuqiang; He, Qing-Yu

2013-01-01

131

MAPK14/p38?-dependent modulation of glucose metabolism affects ROS levels and autophagy during starvation.  

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Increased glycolytic flux is a common feature of many cancer cells, which have adapted their metabolism to maximize glucose incorporation and catabolism to generate ATP and substrates for biosynthetic reactions. Indeed, glycolysis allows a rapid production of ATP and provides metabolic intermediates required for cancer cells growth. Moreover, it makes cancer cells less sensitive to fluctuations of oxygen tension, a condition usually occurring in a newly established tumor environment. Here, we provide evidence for a dual role of MAPK14 in driving a rearrangement of glucose metabolism that contributes to limiting reactive oxygen species (ROS) production and autophagy activation in condition of nutrient deprivation. We demonstrate that MAPK14 is phosphoactivated during nutrient deprivation and affects glucose metabolism at 2 different levels: on the one hand, it increases SLC2A3 mRNA and protein levels, resulting in a higher incorporation of glucose within the cell. This event involves the MAPK14-mediated enhancement of HIF1A protein stability. On the other hand, MAPK14 mediates a metabolic shift from glycolysis to the pentose phosphate pathway (PPP) through the modulation of PFKFB3 (6-phosphofructo-2-kinase/fructose 2,6-bisphosphatase 3) degradation by the proteasome. This event requires the presence of 2 distinct degradation sequences, KEN box and DSG motif Ser273, which are recognized by 2 different E3 ligase complexes. The mutation of either motif increases PFKFB3 resistance to starvation-induced degradation. The MAPK14-driven metabolic reprogramming sustains the production of NADPH, an important cofactor for many reduction reactions and for the maintenance of the proper intracellular redox environment, resulting in reduced levels of ROS. The final effect is a reduced activation of autophagy and an increased resistance to nutrient deprivation. PMID:25046111

Desideri, Enrico; Vegliante, Rolando; Cardaci, Simone; Nepravishta, Ridvan; Paci, Maurizio; Ciriolo, Maria Rosa

2014-09-01

132

Plumbagin inhibits proliferative and inflammatory responses of T cells independent of ROS generation but by modulating intracellular thiols.  

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Plumbagin inhibited activation, proliferation, cytokine production, and graft-versus-host disease in lymphocytes and inhibited growth of tumor cells by suppressing nuclear factor-kappaB (NF-kappaB). Plumbagin was also shown to induce reactive oxygen species (ROS) generation in tumor cells via an unknown mechanism. Present report describes a novel role of cellular redox in modulation of immune responses in normal lymphocytes by plumbagin. Plumbagin depleted glutathione (GSH) levels that led to increase in ROS generation. The decrease in GSH levels was due to direct reaction of plumbagin with GSH as evinced by mass spectrometric and HPLC analysis. Further, addition of plumbagin to cells resulted in decrease in free thiol groups on proteins and increase in glutathionylation of proteins. The suppression of mitogen-induced T-cell proliferation and cytokine (IL-2/IL-4/IL-6/IFN-gamma) production by plumbagin was abrogated by thiol antioxidants but not by non-thiol antioxidants confirming that thiols but not ROS play an important role in biological activity of plumbagin. Plumbagin also abrogated mitogen-induced phosphorylation of ERK, IKK, and degradation of IkappaB-alpha. However, it did not affect phosphorylation of P38, JNK, and AKT. Our results for the first time show that antiproliferative effects of plumbagin are mediated by modulation of cellular redox. These results provide a rationale for application of thiol-depleting agents as anti-inflammatory drugs. PMID:20564204

Checker, Rahul; Sharma, Deepak; Sandur, Santosh K; Subrahmanyam, G; Krishnan, Sunil; Poduval, T B; Sainis, K B

2010-08-01

133

T-2 toxin enhances catabolic activity of hypertrophic chondrocytes through ROS-NF-?B-HIF-2? pathway.  

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T-2 toxin (T-2), one of the most important and toxic trichothecene mycotoxins, can cause many medical problems, such as diarrhea, nervous disorders, immunodepression and death, and is also believed as an etiological factor of Kashin-Beck disease, an endemic osteochondropathy prevailing in North China. However, the molecular mechanisms underlying T-2 effects on tissue damage remain elusive. We differentiated ATDC5 chondrogenic cells into hypertrophic chondrocytes, and found that T-2 reduced the expression of anabolic genes, and increased the expression of catabolic genes. To uncover the mechanism that T-2 influenced metabolic homeostasis of hypertrophic chondrocytes, we observed that T-2 increased the production of reactive oxygen species (ROS) and the degradation of I?B-?, and up-regulated the expression of hypoxia-induced factor-2? (HIF-2?). Bay11-7085 (an inhibitor of NF-?B pathway) inhibited the up-regulation of HIF-2?, and N-acetyl-l-cysteine (a ROS scavenger) inhibited both the decrease of I?B-? and the up-regulation of HIF-2?. Our results demonstrate that ROS-NF-?B-HIF-2? pathway participates in the effects of T-2 on hypertrophic chondrocytes, and HIF-2? plays an important role as a key mediator in this process. PMID:22800716

Tian, Juan; Yan, Jidong; Wang, Wei; Zhong, Nannan; Tian, Lifang; Sun, Jian; Min, Zixin; Ma, Jie; Lu, Shemin

2012-10-01

134

Peroxisome proliferation-related ROS control sets melanocortin tone and feeding in diet-induced obesity  

OpenAIRE

Roles for hypothalamic reactive oxygen species (ROS) in the modulation of circuit activity of the melanocortin system were proposed1,2,. Here we show that suppression of ROS diminished pro-opiomelanocortin (POMC) cell activation and promoted the activity of neuropeptide Y- (NPY)/agouti related peptide- (AgRP) neurons and feeding, whereas ROS activated POMC neurons and reduced feeding. ROS in POMC neurons were positively correlated with leptin levels in lean and ob/ob animals a relationship di...

Diano, Sabrina; Liu, Zhong-wu; Jeong, Jin Kwoan; Dietrich, Marcelo O.; Ruan, Hai-bin; Kim, Esther; Suyama, Shigetomo; Kelly, Kaitlin; Gyengesi, Erika; Arbiser, Jack L.; Belsham, Denise D.; Sarruf, David A.; Schwartz, Michael W.; Bennett, Anton M.; Shanabrough, Marya

2011-01-01

135

ROS Production Is Essential for the Apoptotic Function of E2F1 in Pheochromocytoma and Neuroblastoma Cell Lines  

OpenAIRE

In this study we demonstrate that accumulation of reactive oxygen species (ROS) is essential for E2F1 mediated apoptosis in ER-E2F1 PC12 pheochromocytoma, and SH-SY5Y and SK-N-JD neuroblastoma stable cell lines. In these cells, the ER-E2F1 fusion protein is expressed in the cytosol; the addition of 4-hydroxytamoxifen (OHT) induces its translocation to the nucleus and activation of E2F1target genes. Previously we demonstrated that, in ER-E2F1 PC12 cells, OHT treatment induced apoptosis through...

Espada, Lilia; Meo-evoli, Nathalie; Sancho, Patricia; Real, Sebastian; Fabregat, Isabel; Ambrosio, Santiago; Tauler, Albert

2012-01-01

136

A Key Role for Mg2+ in TRPM7’s Control of ROS Levels During Cell Stress  

OpenAIRE

The TRPM7 channel has been shown to play a pivotal role in cell survival during brain ischemia as well as in the survival of other cell types challenged with apoptotic stimuli. Ca2+ is thought to be central to the channel’s ability to regulate reactive oxygen species (ROS) production. However, channel-mediated entry of Mg2+ and Zn2+ have also been implicated in cell death. Here we show that depletion of TRPM7 by RNA interference in fibroblasts increases cell resistance to apoptotic stimuli ...

Chen, Hsiang-chin; Su, Li-ting; Gonza?lez-paga?n, Omayra; Overton, Jeffrey D.; Runnels, Loren W.

2012-01-01

137

Gravitropic response induced by coumarin: Evidences of ROS distribution involvement  

OpenAIRE

Coumarin effects on gravitropic responses of Arabidopsis thaliana roots were here evaluated. Coumarin alone did not cause any alteration on gravitropic response showing a behavior similar to control plants. In contrast, TIBA and NPA, two auxin transport inhibitors, strongly modified root gravitropic responses. The addition of coumarin to the medium together with TIBA or NPA partially restored the effect of both inhibitors. Simultaneously, a semi-quantitative evaluation of ROS distribution was...

Lupini, Antonio; Araniti, Fabrizio; Sunseri, Francesco; Abenavoli, Maria Rosa

2013-01-01

138

Zeolites are effective ROS-scavengers in vitro.  

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We report on the use of zeolites to limit the effects of reactive oxygen species (ROS) on human albumin under in vitro conditions. Zeolites of different structure type, channel size, channel polarity, and charge-compensating cation were screened for the elimination of ROS, notably HO(·), resulting from the Fenton reaction. A test based on ischemia-modified albumin (IMA) was used as a marker to monitor the activity of HO(·) after co-exposure of human serum to these zeolites. Two commercial zeolites, faujasite (FAU 13×, channel opening 0.74×0.74 nm with Na(+) as charge-compensating cation) and ferrierite (FER, channel opening 0.54×0.42 nm with H(+) as charge-compensating cation), were found to reduce IMA formation by more than 65% due to removal of HO(·) relative to reference values. It was established that partial ion exchange of the zeolites' respective charge-compensating cation vs. Fe(3+) implicated in the Fenton reaction plays a major role in HO(·) deactivation process. Moreover, our results show that no saturation of the respective zeolite active sites occurred. This is possible only when ROS are actively converted to water molecules within the zeolite void system, which generates H(+) ion transport. Because zeolites cannot be administered in blood, their use in medicine should be limited to extra corporeal circuits. Zeolites could be of use during cardiopulmonary bypass or hemodialysis procedures. PMID:21679693

Pellegrino, Perrine; Mallet, Bernard; Delliaux, Stéphane; Jammes, Yves; Guieu, Regis; Schäf, Oliver

2011-07-01

139

ROS-Triggered Signaling Pathways Involved in the Cytotoxicity and Tumor Promotion Effects of Pentachlorophenol and Tetrachlorohydroquinone.  

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Free radical-triggered tissue damage is believed to play an essential role in a variety of human diseases. Pentachlorophenol (PCP) is applied as a pesticide worldwide in both industries and homes. It is used extensively as a biocide and wood preservative. Tetrachlorohydroquinone (TCHQ) was proved as a major toxic metabolite of PCP, contributing the release of free radicals during PCP metabolism. PCP has been proposed as a tumor promoter; however, only limited knowledge is available regarding the mechanisms of tumor promotion induced by PCP and its metabolite, TCHQ. A growing amount of literature suggests that a link between reactive oxygen species (ROS) and tumor promotion could exist. Herein, we summarize the findings regarding the ROS-triggered signaling pathways involved in the cytotoxicity and tumor promotion effects of PCP and TCHQ. Some of the notable findings demonstrated that TCHQ can induce DNA lesions and glutathione depletion in mammalian cells; meanwhile, oxidative stress and apoptosis/necrosis can be found both in vivo and in vitro. Interestingly, PCP and TCHQ were proved as mild tumor promoters in two-stage tumorigenesis models, in which the possible mechanism could be through ROS generation and changed Bcl-2 gene expression. We also found significant effects of antioxidants in attenuating the oxidative stress, cyto- and genotoxicity, and apoptosis/necrosis induced by PCP and/or TCHQ. In addition, mitogen-activated protein kinase (MAPK) activation is involved in PCP/TCHQ-triggered cytotoxicity, as evidenced by the finding that higher doses of TCHQ could lead to necrosis of freshly isolated splenocytes through the production of a large amount of ROS and sustained ERK activation. These results could explain partly the underlying molecular mechanisms contributing to the tumorigenesis induced by PCP. However, the detailed mechanisms of free radicals in triggering PCP/TCHQ-mediated tumor promotion and toxicity are still not completely resolved and need to be investigated further. PMID:25608107

Chen, Hsiu-Min; Lee, Yu-Hsuan; Wang, Ying-Jan

2015-03-16

140

Identifying and Targeting ROS1 Gene Fusions in Non-Small Cell Lung Cancer  

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Purpose Oncogenic gene fusions involving the 3’ region of ROS1 kinase have been identified in various human cancers. In this study, we sought to characterize ROS1 fusion genes in non-small cell lung cancer (NSCLC) and establish the fusion proteins as drug targets. Experimental Design A NSCLC tissue microarray (TMA) panel containing 447 samples was screened for ROS1 rearrangement by fluorescence in-situ hybridization (FISH). This assay was also used to screen NSCLC patients. In positive samples, the identity of the fusion partner was determined through inverse-PCR and RT-PCR. In addition, the clinical utility of ROS1 inhibition was assessed by treating a ROS1-positive patient with crizotinib. The HCC78 cell line, which expresses the SLC34A2-ROS1 fusion, was treated with kinase inhibitors that have activity against ROS1. The effects of ROS1 inhibition on proliferation, cell-cycle progression, and cell signaling pathways were analyzed by MTS assay, flow cytometry, and western blotting. Results In the TMA panel, 5/428 (1.2%) evaluable samples were found to be positive for ROS1 rearrangement. Additionally, 1/48 patients tested positive for rearrangement, and this patient demonstrated tumor shrinkage upon treatment with crizotinib. The patient and one TMA sample displayed expression of the recently identified SDC4-ROS1 fusion, while two TMA samples expressed the CD74-ROS1 fusion and two others expressed the SLC34A2-ROS1 fusion. In HCC78 cells, treatment with ROS1 inhibitors was anti-proliferative and down-regulated signaling pathways that are critical for growth and survival. Conclusions ROS1 inhibition may be an effective treatment strategy for the subset of NSCLC patients whose tumors express ROS1 fusion genes. PMID:22919003

Davies, Kurtis D.; Le, Anh T.; Theodoro, Mariana F.; Skokan, Margaret C.; Aisner, Dara L.; Berge, Eamon M.; Terracciano, Luigi M.; Incarbone, Matteo; Roncalli, Massimo; Cappuzzo, Federico; Camidge, D. Ross; Varella-Garcia, Marileila; Doebele, Robert C.

2013-01-01

141

X-ROS signaling in heart and skeletal muscle: stretch-dependent local ROS regulates [Ca2+]i  

OpenAIRE

X-ROS signaling is a novel redox signaling pathway that links mechanical stress to changes in [Ca2+]i. This pathway is activated rapidly and locally within a muscle cell under physiological conditions, but can also contribute to Ca2+-dependent arrhythmia in heart and to the dystrophic phenotype in heart and skeletal muscle. Upon physiologic cellular stretch, microtubules serve as mechanotransducers to activate NADPH oxidase 2 in the transverse tubules and sarcolemmal membranes to produce reac...

Prosser, Benjamin L.; Khairallah, Ramzi J.; Ziman, Andrew P.; Ward, Christopher W.; Lederer, W. J.

2012-01-01

142

Protective Effects of Andrographolide Analogue AL-1 on ROS-Induced RIN-m? Cell Death by Inducing ROS Generation  

OpenAIRE

Oxidative stress is considered to be a major factor contributing to pathogenesis and progression of many diseases. A novel andrographolide-lipoic acid conjugate (AL-1) could protect pancreatic ?-cells from reactive oxygen species (ROS)-induced oxidative injury. However, its protective mechanism is still unclear. In this work, we used proteomics to identify AL-1-regulated proteins in ?-cells and found that 13 of the 71 proteins regulated by AL-1 were closely associated with antioxidation. Th...

Yan, Guang-rong; Zhou, Hui-hua; Wang, Yang; Zhong, Yin; Tan, Zi-lu; Wang, Yuqiang; He, Qing-yu

2013-01-01

143

MicroRNA-145 suppresses ROS-induced Ca{sup 2+} overload of cardiomyocytes by targeting CaMKII?  

Energy Technology Data Exchange (ETDEWEB)

Highlights: •CaMKII? mediates H{sub 2}O{sub 2}-induced Ca{sup 2+} overload in cardiomyocytes. •miR-145 can inhibit Ca{sup 2+} overload. •A luciferase assay confirms that miR-145 functions as a CaMKII?-targeting miRNA. •Overexpression of miR-145 regulates CaMKII?-related genes and ameliorates apoptosis. -- Abstract: A change in intracellular free calcium (Ca{sup 2+}) is a common signaling mechanism of reperfusion-induced cardiomyocyte death. Calcium/calmodulin dependent protein kinase II (CaMKII) is a critical regulator of Ca{sup 2+} signaling and mediates signaling pathways responsible for functions in the heart including hypertrophy, apoptosis, arrhythmia, and heart disease. MicroRNAs (miRNA) are involved in the regulation of cell response, including survival, proliferation, apoptosis, and development. However, the roles of miRNAs in Ca{sup 2+}-mediated apoptosis of cardiomyocytes are uncertain. Here, we determined the potential role of miRNA in the regulation of CaMKII dependent apoptosis and explored its underlying mechanism. To determine the potential roles of miRNAs in H{sub 2}O{sub 2}-mediated Ca{sup 2+} overload, we selected and tested 6 putative miRNAs that targeted CaMKII?, and showed that miR-145 represses CaMKII? protein expression and Ca{sup 2+} overload. We confirmed CaMKII? as a direct downstream target of miR-145. Furthermore, miR-145 regulates Ca{sup 2+}-related signals and ameliorates apoptosis. This study demonstrates that miR-145 regulates reactive oxygen species (ROS)-induced Ca{sup 2+} overload in cardiomyocytes. Thus, miR-145 affects ROS-mediated gene regulation and cellular injury responses.

Cha, Min-Ji [Cardiovascular Research Institute, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Jang, Jin-Kyung [College of Pharmacy, Sookmyung Women’s University, 52 HyoChangWon-Gil, Yongsan-ku, Seoul 140-742 (Korea, Republic of); Ham, Onju; Song, Byeong-Wook; Lee, Se-Yeon [Cardiovascular Research Institute, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Lee, Chang Yeon; Park, Jun-Hee [Department of Integrated Omics for Biomedical Sciences, Graduate School, Yonsei University, 50 Yonsei-ro, Seodamun-gu, Seoul 120-759 (Korea, Republic of); Lee, Jiyun; Seo, Hyang-Hee [Cardiovascular Research Institute, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Choi, Eunhyun [Severance Integrative Research Institute for Cerebral and Cardiovascular Disease, Yonsei University Health System, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Jeon, Woo-min [Department of Animal Resource, Sahmyook University, Seoul 139-742 (Korea, Republic of); Hwang, Hye Jin [Cardiovascular Research Institute, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Shin, Hyun-Taek [College of Pharmacy, Sookmyung Women’s University, 52 HyoChangWon-Gil, Yongsan-ku, Seoul 140-742 (Korea, Republic of); and others

2013-06-14

144

Damaged DNA Binding Protein 2 in Reactive Oxygen Species (ROS Regulation and Premature Senescence  

Directory of Open Access Journals (Sweden)

Full Text Available Premature senescence induced by DNA damage or oncogene is a critical mechanism of tumor suppression. Reactive oxygen species (ROS have been implicated in the induction of premature senescence response. Several pathological disorders such as cancer, aging and age related neurological abnormalities have been linked to ROS deregulation. Here, we discuss how Damaged DNA binding Protein-2 (DDB2, a nucleotide excision repair protein, plays an important role in ROS regulation by epigenetically repressing the antioxidant genes MnSOD and Catalase. We further revisit a model in which DDB2 plays an instrumental role in DNA damage induced ROS accumulation, ROS induced premature senescence and inhibition of skin tumorigenesis.

Pradip Raychaudhuri

2012-09-01

145

Effect of Methyl Jasmonate on antioxidative enzyme activities and on the contents of ROS and H2O2 in Ricinus communis leaves  

OpenAIRE

Jasmonates are a class of plant hormones that mediate various aspects in gene and metabolic regulation, defense, stress responses, reproduction and, possibly, communication. Oxidative stress stimulates synthesis of antioxidant metabolites and enhances antioxidant enzyme activities that could protect plant tissues. The aim of this study was to verify the effects of methyl jasmonate (JAME) treatment on the reactive oxygen species (ROS) and on the activities of H2O2 scavenging enzymes, such as s...

Alexandra Martins dos Santos Soares; Thiago Freitas de Souza; Tânia Jacinto; Olga Lima Tavares Machado

2010-01-01

146

Cysteine-mediated redox signalling in the mitochondria.  

Science.gov (United States)

The mitochondria are critical mediators of cellular redox homeostasis due to their role in the generation and dissipation of reactive oxygen/nitrogen species (ROS/RNS). Modulations in ROS/RNS levels in the mitochondria are often reflected through oxidation/nitrosation of highly redox-sensitive cysteine residues within this organelle. Oxidation/nitrosation of functional cysteines on mitochondrial proteins serves to modulate protein activity, localization, and complexation in response to cellular stress, thereby controlling critical processes such as oxidative phosphorylation, apoptosis, and redox signalling. In this review, we describe mitochondrial sources of ROS/RNS, cysteine modifications that are triggered by increased mitochondrial ROS/RNS, and examples of key mitochondrial proteins that are regulated through cysteine-mediated redox signalling. We highlight recent advancements in proteomic methods to study cysteine posttranslational modifications. These tools will further aid in illuminating the important role of cysteine in maintaining and transducing redox signals in the mitochondria. PMID:25519845

Bak, D W; Weerapana, E

2015-03-17

147

Redirecting apoptosis to aponecrosis induces selective cytotoxicity to pancreatic cancer cells through increased ROS, decline in ATP levels, and VDAC.  

Science.gov (United States)

Pancreatic cancer cell lines with mutated ras underwent an alternative form of cell death (aponecrosis) when treated concomitantly with clinically achievable concentrations of arsenic trioxide, ascorbic acid, and disulfiram (Antabuse; AAA). AAA's major effects are mediated through generation of intracellular reactive oxygen species (ROS) and more than 50% decline in intracellular ATP. N-acetyl cysteine and a superoxide dismutase mimetic prevented aponecrosis and restored intracellular ATP levels. DIDS (4,4'-diisothiocyanatostilbene-2, 2' disulfonic acid), the pan- Voltage-Dependent Anion Channel (VDAC), -1, 2, 3 inhibitor and short hairpin RNA (shRNA) to VDAC-1 blocked cell death and ROS accumulation. In vivo exposure of AAA led to a 62% reduction in mean tumor size and eliminated tumors in 30% of nude mice with PANC-1 xenografts. We concluded that early caspase-independent apoptosis was shifted to VDAC-mediated "targeted" aponecrosis by the addition of disulfiram to arsenic trioxide and ascorbic acid. Conceptually, this work represents a paradigm shift where switching from apoptosis to aponecrosis death pathways, also known as targeted aponecrosis, could be utilized to selectively kill pancreatic cancer cells resistant to apoptosis. PMID:24126434

Dinnen, Richard D; Mao, Yuehua; Qiu, Wanglong; Cassai, Nicholas; Slavkovich, Vesna N; Nichols, Gwen; Su, Gloria H; Brandt-Rauf, Paul; Fine, Robert L

2013-12-01

148

Metal-Sulfate Induced Generation of ROS in Human Brain Cells: Detection Using an Isomeric Mixture of 5- and 6-Carboxy-2?,7?-Dichlorofluorescein Diacetate (Carboxy-DCFDA as a Cell Permeant Tracer  

Directory of Open Access Journals (Sweden)

Full Text Available Evolution of reactive oxygen species (ROS, generated during the patho-physiological stress of nervous tissue, has been implicated in the etiology of several progressive human neurological disorders including Alzheimer’s disease (AD and amylotrophic lateral sclerosis (ALS. In this brief communication we used mixed isomers of 5-(and-6-carboxy-2?,7?-dichlorofluorescein diacetate (carboxy-DCFDA; C25H14Cl2O9; MW 529.3, a novel fluorescent indicator, to assess ROS generation within human neuronal-glial (HNG cells in primary co-culture. We introduced pathological stress using the sulfates of 12 environmentally-, industrially- and agriculturally-relevant divalent and trivalent metals including Al, Cd, Cu, Fe, Hg, Ga, Mg, Mn, Ni, Pb, Sn and Zn. In this experimental test system, of all the metal sulfates analyzed, aluminum sulfate showed by far the greatest ability to induce intracellular ROS. These studies indicate the utility of using isomeric mixtures of carboxy-H2DCFDA diacetates as novel and highly sensitive, long-lasting, cell-permeant, fluorescein-based tracers for quantifying ROS generation in intact, metabolizing human brain cells, and in analyzing the potential epigenetic contribution of different metal sulfates to ROS-generation and ROS-mediated neurological dysfunction.

Walter J. Lukiw

2012-08-01

149

Advanced Query and Data Mining Capabilities for MaROS  

Science.gov (United States)

The Mars Relay Operational Service (MaROS) comprises a number of tools to coordinate, plan, and visualize various aspects of the Mars Relay network. These levels include a Web-based user interface, a back-end "ReSTlet" built in Java, and databases that store the data as it is received from the network. As part of MaROS, the innovators have developed and implemented a feature set that operates on several levels of the software architecture. This new feature is an advanced querying capability through either the Web-based user interface, or through a back-end REST interface to access all of the data gathered from the network. This software is not meant to replace the REST interface, but to augment and expand the range of available data. The current REST interface provides specific data that is used by the MaROS Web application to display and visualize the information; however, the returned information from the REST interface has typically been pre-processed to return only a subset of the entire information within the repository, particularly only the information that is of interest to the GUI (graphical user interface). The new, advanced query and data mining capabilities allow users to retrieve the raw data and/or to perform their own data processing. The query language used to access the repository is a restricted subset of the structured query language (SQL) that can be built safely from the Web user interface, or entered as freeform SQL by a user. The results are returned in a CSV (Comma Separated Values) format for easy exporting to third party tools and applications that can be used for data mining or user-defined visualization and interpretation. This is the first time that a service is capable of providing access to all cross-project relay data from a single Web resource. Because MaROS contains the data for a variety of missions from the Mars network, which span both NASA and ESA, the software also establishes an access control list (ACL) on each data record in the database repository to enforce user access permissions through a multilayered approach.

Wang, Paul; Wallick, Michael N.; Allard, Daniel A.; Gladden, Roy E.; Hy, Franklin H.

2013-01-01

150

Capsaicin stimulates glucose uptake in C2C12 muscle cells via the reactive oxygen species (ROS)/AMPK/p38 MAPK pathway.  

Science.gov (United States)

Capsaicin has been reported to regulate blood glucose levels and to ameliorate insulin resistance in obese mice. This study demonstrates that capsaicin increases glucose uptake directly by activating AMP-activated protein kinase (AMPK) in C2C12 muscle cells, which manifested as an attenuation of glucose uptake when compound C, an AMPK inhibitor, was co-administered with capsaicin. However, the insulin signaling molecules insulin receptor substrate-1 (IRS-1) and Akt were not affected by capsaicin. Additional results showed that p38 mitogen-activated protein kinase (MAPK) is also involved in capsaicin-induced glucose transport downstream of AMPK because capsaicin increased p38 MAPK phosphorylation significantly and its specific inhibitor SB203580 inhibited capsaicin-mediated glucose uptake. Treatment with an AMPK inhibitor reduced p38 MAPK phosphorylation, but the p38 MAPK inhibitor had no effect on AMPK. Capsaicin stimulated ROS generation in C2C12 muscle cells, and when ROS were captured using the nonspecific antioxidant NAC, the increase in both capsaicin-induced AMPK phosphorylation and capsaicin-induced glucose uptake was attenuated, suggesting that ROS function as an upstream activator of AMPK. Taken together, these results suggest that capsaicin, independent of insulin, increases glucose uptake via ROS generation and consequent AMPK and p38 MAPK activations. PMID:23958300

Kim, Soon-Hee; Hwang, Jin-Taek; Park, Hee Sook; Kwon, Dae Young; Kim, Myung-Sunny

2013-09-13

151

Chlorella Induces Stomatal Closure via NADPH Oxidase-Dependent ROS Production and Its Effects on Instantaneous Water Use Efficiency in Vicia faba  

Science.gov (United States)

Reactive oxygen species (ROS) have been established to participate in stomatal closure induced by live microbes and microbe-associated molecular patterns (MAMPs). Chlorella as a beneficial microorganism can be expected to trigger stomatal closure via ROS production. Here, we reported that Chlorella induced stomatal closure in a dose-and time-dependent manner in epidermal peels of Vicia faba. Using pharmacological methods in this work, we found that the Chlorella-induced stomatal closure was almost completely abolished by a hydrogen peroxide (H2O2) scavenger, catalase (CAT), significantly suppressed by an NADPH oxidase inhibitor, diphenylene iodonium chloride (DPI), and slightly affected by a peroxidase inhibitor, salicylhydroxamic acid (SHAM), suggesting that ROS production involved in Chlorella-induced stomatal closure is mainly mediated by DPI-sensitive NADPH oxidase. Additionally, Exogenous application of optimal concentrations of Chlorella suspension improved instantaneous water use efficiency (WUEi) in Vicia faba via a reduction in leaf transpiration rate (E) without a parallel reduction in net photosynthetic rate (Pn) assessed by gas-exchange measurements. The chlorophyll fluorescence and content analysis further demonstrated that short-term use of Chlorella did not influence plant photosynthetic reactions center. These results preliminarily reveal that Chlorella can trigger stomatal closure via NADPH oxidase-dependent ROS production in epidermal strips and improve WUEi in leave levels. PMID:24687099

Li, Yan; Xu, Shan-Shan; Gao, Jing; Pan, Sha; Wang, Gen-Xuan

2014-01-01

152

Involvement of reactive oxygen species (ROS) in the induction of genetic instability by radiation  

International Nuclear Information System (INIS)

Radiation generates reactive oxygen species (ROS) that interact with cellular molecules, including DNA, lipids, and proteins. To know how ROS contribute to the induction of genetic instability, we examined the effect of the anti-ROS condition, using both ascorbic acid phosphate (APM) treatment or a low oxygen condition, on the induction of delayed reproductive cell death and delayed chromosome aberrations. The primary surviving colonies of mouse m5S-derived cl. 2011-14 cells irradiated with 6 Gy of X-rays were replated and allowed to form secondary colonies. The anti-ROS treatments were applied to either preirradiation culture or postirradiation cultures for primary or secondary colony formation. Both anti-ROS conditions relieved X-ray-induced acute cell killing to a similar extent. These anti-ROS conditions also relieved genetic instability when those conditions were applied during primary colony formation. However, no effect was observed when the conditions were applied during preirradiation culture and secondary colony formation. We also demonstrated that the amounts of ROS in X-ray-irradiated cells rapidly increase and then decrease at 6 hr postirradiation, and the levels of ROS then gradually decrease to a baseline within 2 weeks. The APM treatment kept the ROS production at a lower level than an untreated control. These results suggest that the cause of genetic instability might be fixed by ROS during a 2-week postirradiation period. (author)ation period. (author)

153

A novel synthetic analog of militarin, MA-1 induces mitochondrial dependent apoptosis by ROS generation in human lung cancer cells  

Energy Technology Data Exchange (ETDEWEB)

A synthetic Militarin analog-1[(2R,3R,4R,5R)-1,6-bis(4-(2,4,4-trimethylpentan-2-yl)phenoxy) hexane-2,3,4,5-tetraol] is a novel derivative of constituents from Cordyceps militaris, which has been used to treat a variety of chronic diseases including inflammation, diabetes, hyperglycemia and cancers. Here, we report for the first time the synthesis of Militarin analog-1 (MA-1) and the apoptotic mechanism of MA-1 against human lung cancer cell lines. Treatment with MA-1 significantly inhibited the viability of 3 human lung cancer cell lines. The inhibition of viability and growth in MA-1-treated A549 cells with an IC{sub 50} of 5 ?M were mediated through apoptosis induction, as demonstrated by an increase in DNA fragmentation, sub-G{sub 0}/G{sub 1}-DNA fraction, nuclear condensation, and phosphatidylserine exposure. The apoptotic cell death caused mitochondrial membrane permeabilization through regulation of expression of the Bcl-2 family proteins, leading to cytochrome c release in a time-dependent manner. Subsequently, the final stage of apoptosis, activation of caspase-9/-3 and cleavage of poly (ADP ribose) polymerase, was induced. Furthermore, A549 lung cancer cells were more responsive to MA-1 than a bronchial epithelial cell line (BEAS-2B), involving the rapid generation of reactive oxygen species (ROS), c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) activation. The pharmacological inhibition of ROS generation and JNK/p38 MAPK exhibited attenuated DNA fragmentation in MA-1-induced apoptosis. Oral administration of MA-1 also retarded growth of A549 orthotopic xenografts. In conclusion, the present study indicates that the new synthetic derivative MA-1 triggers mitochondrial apoptosis through ROS generation and regulation of MAPKs and may be a potent therapeutic agent against human lung cancer. - Highlights: • We report a novel synthesized derivative, militarin analog-1 (MA-1). • MA-1-induced cancer cell death was triggered by the ROS generation through MAPKs. • The MA-1-induced cell death was also modulated by the mitochondria-mediated pathway. • The apoptotic cancer cell death by MA-1 was also exhibited in orthotopic xenografts. • Our findings suggest MA-1 as a clinically useful agent for human lung cancer.

Yoon, Deok Hyo; Lim, Mi-Hee [Department of Biochemistry, Kangwon National University, Chuncheon 200-701 (Korea, Republic of); Lee, Yu Ran [Department of Physiology, School of Medicine, Chungnam National University, Daejeon 301-747 (Korea, Republic of); Sung, Gi-Ho [Mushroom Research Division, National Institute of Horticultural and Herbal Science, Rural Development Administration, Suwon 404-707 (Korea, Republic of); Lee, Tae-Ho [R and D Center, Dong-A Pharmaceutical Co, Ltd, Yongin 446-905 (Korea, Republic of); Jeon, Byeong Hwa [Department of Physiology, School of Medicine, Chungnam National University, Daejeon 301-747 (Korea, Republic of); Cho, Jae Youl [Department of Genetic Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Song, Won O. [Department of Food Science and Human Nutrition, Michigan State University, East Lansing, MI 48824 (United States); Park, Haeil [College of Pharmacy, Kangwon National University, Chuncheon 200-701 (Korea, Republic of); Choi, Sunga, E-mail: sachoi@cnu.ac.kr [Department of Physiology, School of Medicine, Chungnam National University, Daejeon 301-747 (Korea, Republic of); Kim, Tae Woong, E-mail: tawkim@kangwon.ac.kr [Department of Biochemistry, Kangwon National University, Chuncheon 200-701 (Korea, Republic of)

2013-12-15

154

Ionized gas (plasma) delivery of reactive oxygen species (ROS) into artificial cells  

Science.gov (United States)

This study was designed to enhance our understanding of how reactive oxygen species (ROS), generated ex situ by ionized gas (plasma), can affect the regulation of signalling processes within cells. A model system, comprising of a suspension of phospholipid vesicles (cell mimics) encapsulating a ROS reporter, was developed to study the plasma delivery of ROS into cells. For the first time it was shown that plasma unequivocally delivers ROS into cells over a sustained period and without compromising cell membrane integrity. An important consideration in cell and biological assays is the presence of serum, which significantly reduced the transfer efficiency of ROS into the vesicles. These results are key to understanding how plasma treatments can be tailored for specific medical or biotechnology applications. Further, the phospholipid vesicle ROS reporter system may find use in other studies involving the application of free radicals in biology and medicine.

Hong, Sung-Ha; Szili, Endre J.; Jenkins, A. Toby A.; Short, Robert D.

2014-09-01

155

Hyperoxygenation Attenuated a Murine Model of Atopic Dermatitis through Raising Skin Level of ROS  

OpenAIRE

Atopic dermatitis (AD) is a chronic inflammatory skin disease resulting from excessive stimulation of immune cells. Traditionally, reactive oxygen species (ROS) have been implicated in the progression of inflammatory diseases, but several opposing observations suggest the protective role of ROS in inflammatory disease. Recently, we demonstrated ROS prevented imiquimod-induced psoriatic dermatitis through enhancing regulatory T cell function. Thus, we hypothesized AD might also be attenuated i...

Kim, Hyung-ran; Kim, Jung-hwan; Choi, Eun-jeong; Lee, Yeo Kyong; Kie, Jeong-hae; Jang, Myoung Ho; Seoh, Ju-young

2014-01-01

156

Damaged DNA Binding Protein 2 in Reactive Oxygen Species (ROS) Regulation and Premature Senescence  

OpenAIRE

Premature senescence induced by DNA damage or oncogene is a critical mechanism of tumor suppression. Reactive oxygen species (ROS) have been implicated in the induction of premature senescence response. Several pathological disorders such as cancer, aging and age related neurological abnormalities have been linked to ROS deregulation. Here, we discuss how Damaged DNA binding Protein-2 (DDB2), a nucleotide excision repair protein, plays an important role in ROS regulation by epigenetically rep...

Pradip Raychaudhuri; Srilata Bagchi; Nilotpal Roy

2012-01-01

157

The alternative Medicago truncatula defense proteome of ROS—defective transgenic roots during early microbial infection  

OpenAIRE

ROP-type GTPases of plants function as molecular switches within elementary signal transduction pathways such as the regulation of ROS synthesis via activation of NADPH oxidases (RBOH-respiratory burst oxidase homolog in plants). Previously, we reported that silencing of the Medicago truncatula GTPase MtROP9 led to reduced ROS production and suppressed induction of ROS-related enzymes in transgenic roots (MtROP9i) infected with pathogenic (Aphanomyces euteiches) and symbiotic microorganisms (...

Kiirika, Leonard M.; Schmitz, Udo; Colditz, Frank

2014-01-01

158

Rho GTPases and Nox dependent ROS production in skin. Is there a connection?  

DEFF Research Database (Denmark)

Rho GTPases are a family of small GTP binding proteins most commonly known for the regulation of many cellular processes, including actin cytoskeleton re-organisation, cell proliferation, signal transduction and regulation of apoptosis. Additionally, a link between Rho GTPases and reactive oxygen species (ROS) has been shown. In line with the growing interest in the role of ROS in cell biology, the relevance of this connection is becoming increasingly clearer. ROS production is classically associated with oxidative metabolic pathways (e.g. respiratory chain, arachidonic acid). During these metabolic pathways, ROS are produced as by-products and these can be potentially toxic. However, numerous cell types contain dedicated enzymatic complexes, i.e., NADPH oxidase (Nox) complexes, for regulated production of ROS. This regulated production of ROS seems to be important for a number of fundamental cell biological processes, including cell growth, differentiation, migration, angiogenesis, aimed at maintaining tissue homeostasis. Data suggests that skin cells are capable of a regulated ROS production via Nox complexes. Members of the Rho GTPase family have been found to play a central regulatory role in Nox activity. In the present review we will focus on the involvement of Rho GTPases in regulated production of ROS with special emphasis on the skin. We will also discuss the possibility that some in vivo effects of the deletion of members of the Rho GTPase family in skin cells could potentially be linked to a reduced ability of regulated ROS production.

Stanley, Alanna; Hynes, Ailish

2012-01-01

159

Characterization of ROS1 cDNA from a human glioblastoma cell line  

International Nuclear Information System (INIS)

The authors have isolated and characterized a human ROS1 cDNA from the glioblastoma cell line SW-1088. The cDNA, 8.3 kilobases long, has the potential to encode a transmembrane tyrosine-specific protein kinase with a predicted molecular mass of 259 kDa. The putative extracellular domain of ROS1 is homologous to the extracellular domain of the sevenless gene product from Drosophila. No comparable similarities in the extracellular domains were found between ROS1 and other receptor-type tyrosine kinases. Together, ROS1 and sevenless gene products define a distinct subclass of transmember tyrosine kinases

160

Investigation of atmospheric particle-bound reactive oxidative species (ROS): Their sources, characterization, and measurement  

Science.gov (United States)

The relationships between the observed ROS concentrations in the New York City PMTACS study and various other atmospheric indicator species such as O3, HOx radicals, organic carbon (OC), elemental carbon (EC) and secondary organic carbon (SOC), as well as the statistical significance of any observable correlations were explored. A statistically significant moderate positive correlation between the O3 and the ROS concentrations, that indicated the local intensity of photochemistry was a moderate factor affecting the formation of particulate ROS in the daytime atmosphere, was observed. The results of the comparison between ROS and HO x concentrations indicated the existence of, at best, a weak positive correlation. The lack of a more positive correlation of the particle-bound ROS, both with ozone as well as other gas phase oxidants, showed the decoupling of the particulate matter ROS from the gas phase oxidants. The comparison of ROS concentrations with OC, EC, and SOC concentrations revealed a statistically significant relationship (P-value measured ROS was photochemically driven. The absence of any statistical relevance of primary EC and OC concentrations on the ROS concentrations suggested that primary emissions, especially from motor vehicles, were not a major source of the measured particle-bound ROS. An important objective of this work was to develop a system that could provide a stable throughput of particle-bound ROS, and characterize it in terms of particle size distribution, concentrations, and formed products, such that the results obtained could be viewed in the perspective of atmospheric processes and measurements. A ROS-bearing particle generator was developed, that could deliver known exposures of ROS. It was seen that the system was generally stable with an average ROS generation capability of 5.6 nanomoles of equivalent H2O2/m3 of (aerosol+ozone) flow sampled. Additionally, the alpha-pinene-O3 oxidation chemical system, used in the ROS generator, was studied to elucidate the structures of reaction products using liquid chromatography-multiple stage mass spectrometry (LC/MSn). The classes of compounds identified based on their multiple stage-MS fragmentation patterns, mechanistic considerations of alpha-pinene-O 3 oxidation, and general fragmentation rules, of the products from this reaction system were highly oxygenated species, predominantly containing hydroperoxide and peroxide functional groups. The oxidant species observed were clearly stable for the 1-3 hrs that elapsed during aerosol collection and analysis, and probably for much longer, thus rendering it possible for these species to bind onto particles forming fine particulate organic peroxides that concentrate on the particles and could deliver concentrated doses of ROS in vivo to tissue. The lack of a suitable method to measure ROS on a routine basis has resulted in no work being undertaken to assess the effects of particle-bound ROS on health effects. In order to fill this need, an automated monitor for the sampling of ambient aerosol and the measurement of concentrations of ROS on the sampled aerosol was developed. Potential methods to quantify ROS were compared in order to arrive at a suitable method to automate. The Dichlorofluorescein (DCFH) fluorescence method was found to be the most non-specific, and hence the best suited method for the automated monitor. An integrated sampling-analysis system was designed and constructed based on collection of atmospheric particles in an aqueous slurry, and subsequent detection of the ROS concentration of the slurry using the DCFH fluorescence method. The results of the lab-scale investigation of the ROS sampling-analysis system suggested that the prototype continuous system was capable of detecting particle-bound ROS, and accounting for short-term variabilitie

Venkatachari, Prasanna

161

Role of Mitochondrial Electron Transport Chain Complexes in Capsaicin Mediated Oxidative Stress Leading to Apoptosis in Pancreatic Cancer Cells  

OpenAIRE

We evaluated the mechanism of capsaicin-mediated ROS generation in pancreatic cancer cells. The generation of ROS was about 4–6 fold more as compared to control and as early as 1 h after capsaicin treatment in BxPC-3 and AsPC-1 cells but not in normal HPDE-6 cells. The generation of ROS was inhibited by catalase and EUK-134. To delineate the mechanism of ROS generation, enzymatic activities of mitochondrial complex-I and complex-III were determined in the pure mitochondria. Our results show...

Pramanik, Kartick C.; Boreddy, Srinivas Reddy; Srivastava, Sanjay K.

2011-01-01

162

Bioreductively Activated Reactive Oxygen Species (ROS) Generators as MRSA Inhibitors.  

Science.gov (United States)

The number of cases of drug resistant Staphylococcus aureus infections is on the rise globally and new strategies to identify drug candidates with novel mechanisms of action are in urgent need. Here, we report the synthesis and evaluation of a series of benzo[b]phenanthridine-5,7,12(6H)-triones, which were designed based on redox-active natural products. We find that the in vitro inhibitory activity of 6-(prop-2-ynyl)benzo[b]phenanthridine-5,7,12(6H)-trione (1f) against methicillin-resistant Staphylococcus aureus (MRSA), including a panel of patient-derived strains, is comparable or better than vancomycin. We show that the lead compound generates reactive oxygen species (ROS) in the cell, contributing to its antibacterial activity. PMID:25050164

Khodade, Vinayak S; Sharath Chandra, Mallojjala; Banerjee, Ankita; Lahiri, Surobhi; Pulipeta, Mallikarjuna; Rangarajan, Radha; Chakrapani, Harinath

2014-07-10

163

Effects of osteotropic hormones on the nitric oxide production in culture of ROS17/2.8 cells  

International Nuclear Information System (INIS)

We performed the present study to investigate whether osteotropic hormones play roles on the nitric oxide (NO) production in culture of ROS17/2.8 osteoblastic cells. The osteoblastic cell line ROS17/2.8 cells were cultured in F12 medium supplemented with 5% fetal bovine serum (FBS) at 37.deg. C in a humidified atmosphere of 5% CO2 in air. ROS17/2.8 cells were plated in 96-well plants at a density of 2-3 x 103 cells/well and grown to confluence. Then the cells were pretreated with osteotropic hormones (parathyroid hormone (PTH) 20-500 ng/mL, 1, 25-dihydroxycholecalciferol (1, 25[OH]2D3) 1-100nM ; prostaglandin E2(PGE2) 20-500 ng/mL) in the medium supplemented with 0.4% FBS for (72 hours and the cells were treated with cytokines (TNF? and IFN?) in phenol red-free F12 medium for an additional 48 hours. NO synthesis was assessed by measuring the nitrite anion concentration, the reation product of NO, in the cell culture medium using Griess reagent. PTH and 1, 25[OH]2D4 pretreatment induced a significant increase in NO production in the presence of TNF? and IFN?. PGE2 slightly induced NO production compared to the control group. But, PGE2 pretreatment did not affect in NO production in the presence of TNF? and IFN?. These results suggest that the actions of osteotropic hormones in bone metabolism may be partially mediated by NO in the presence of cytokinesy NO in the presence of cytokines

164

Transcriptomics and Functional Genomics of ROS-Induced Cell Death Regulation by RADICAL-INDUCED CELL DEATH1  

Science.gov (United States)

Plant responses to changes in environmental conditions are mediated by a network of signaling events leading to downstream responses, including changes in gene expression and activation of cell death programs. Arabidopsis thaliana RADICAL-INDUCED CELL DEATH1 (RCD1) has been proposed to regulate plant stress responses by protein-protein interactions with transcription factors. Furthermore, the rcd1 mutant has defective control of cell death in response to apoplastic reactive oxygen species (ROS). Combining transcriptomic and functional genomics approaches we first used microarray analysis in a time series to study changes in gene expression after apoplastic ROS treatment in rcd1. To identify a core set of cell death regulated genes, RCD1-regulated genes were clustered together with other array experiments from plants undergoing cell death or treated with various pathogens, plant hormones or other chemicals. Subsequently, selected rcd1 double mutants were constructed to further define the genetic requirements for the execution of apoplastic ROS induced cell death. Through the genetic analysis we identified WRKY70 and SGT1b as cell death regulators functioning downstream of RCD1 and show that quantitative rather than qualitative differences in gene expression related to cell death appeared to better explain the outcome. Allocation of plant energy to defenses diverts resources from growth. Recently, a plant response termed stress-induced morphogenic response (SIMR) was proposed to regulate the balance between defense and growth. Using a rcd1 double mutant collection we show that SIMR is mostly independent of the classical plant defense signaling pathways and that the redox balance is involved in development of SIMR. PMID:24550736

Salojärvi, Jarkko; Cui, Fuqiang; Sipari, Nina; Leppälä, Johanna; Lamminmäki, Airi; Tomai, Gloria; Narayanasamy, Shaman; Reddy, Ramesha A.; Keinänen, Markku; Overmyer, Kirk; Kangasjärvi, Jaakko

2014-01-01

165

TCF2 attenuates FFA-induced damage in islet ?-cells by regulating production of insulin and ROS.  

Science.gov (United States)

Free fatty acids (FFAs) are cytotoxic to pancreatic islet ?-cells and play a crucial role in the diabetes disease process. A recent study revealed a down-regulation of transcription factor 2 (TCF2) levels during FFA-mediated cytotoxicity in pancreatic ?-cells. However, its function during this process and the underlying mechanism remains unclear. In this study, treatment with palmitic acid (PA) at high levels (400 and 800 ?M) decreased ?-cell viability and TCF2 protein expression, along with the glucose-stimulated insulin secretion (GSIS). Western and RT-PCR analysis confirmed the positive regulatory effect of TCF2 on GSIS through promotion of the key regulators pancreatic duodenal homeobox-1 (PDX1) and glucose transporter 2 (GLUT2) in ?-cells. In addition, both PI3K/AKT and MEK/ERK showed decreased expression in PA (800 ?M)-treated ?-cells. Overexpression of TCF2 could effectively restore the inhibitory effect of PA on the activation of PI3K/AKT and MEK/ERK as well as ?-cell viability, simultaneously, inhibited PA-induced reactive oxygen species (ROS) generation. After blocking the PI3K/AKT and MAPK/ERK signals with their specific inhibitor, the effect of overexpressed TCF2 on ?-cell viability and ROS production was obviously attenuated. Furthermore, a protective effect of TCF2 on GSIS by positive modulation of JNK-PDX1/GLUT2 signaling was also confirmed. Accordingly, our study has confirmed that TCF2 positively modulates insulin secretion and further inhibits ROS generation via the PI3K/AKT and MEK/ERK signaling pathways. Our work may provide a new therapeutic target to achieve prevention and treatment of diabetes. PMID:25079440

Quan, Xiaojuan; Zhang, Lin; Li, Yingna; Liang, Chunlian

2014-01-01

166

TCF2 Attenuates FFA-Induced Damage in Islet ?-Cells by Regulating Production of Insulin and ROS  

Directory of Open Access Journals (Sweden)

Full Text Available Free fatty acids (FFAs are cytotoxic to pancreatic islet ?-cells and play a crucial role in the diabetes disease process. A recent study revealed a down-regulation of transcription factor 2 (TCF2 levels during FFA-mediated cytotoxicity in pancreatic ?-cells. However, its function during this process and the underlying mechanism remains unclear. In this study, treatment with palmitic acid (PA at high levels (400 and 800 ?M decreased ?-cell viability and TCF2 protein expression, along with the glucose-stimulated insulin secretion (GSIS. Western and RT-PCR analysis confirmed the positive regulatory effect of TCF2 on GSIS through promotion of the key regulators pancreatic duodenal homeobox-1 (PDX1 and glucose transporter 2 (GLUT2 in ?-cells. In addition, both PI3K/AKT and MEK/ERK showed decreased expression in PA (800 ?M-treated ?-cells. Overexpression of TCF2 could effectively restore the inhibitory effect of PA on the activation of PI3K/AKT and MEK/ERK as well as ?-cell viability, simultaneously, inhibited PA-induced reactive oxygen species (ROS generation. After blocking the PI3K/AKT and MAPK/ERK signals with their specific inhibitor, the effect of overexpressed TCF2 on ?-cell viability and ROS production was obviously attenuated. Furthermore, a protective effect of TCF2 on GSIS by positive modulation of JNK-PDX1/GLUT2 signaling was also confirmed. Accordingly, our study has confirmed that TCF2 positively modulates insulin secretion and further inhibits ROS generation via the PI3K/AKT and MEK/ERK signaling pathways. Our work may provide a new therapeutic target to achieve prevention and treatment of diabetes.

Xiaojuan Quan

2014-07-01

167

Up-regulation of ROS by mitochondria-dependent bystander signaling contributes to genotoxicity of bystander effects  

Energy Technology Data Exchange (ETDEWEB)

Genomic instability can be observed in bystander cells. However, the underlying mechanism(s) is still relatively unclear. In a previous study, we found that irradiated cells released mitochondria-dependent intracellular factor(s) which could lead to bystander {gamma}-H2AX induction. In this paper, we used normal ({rho}{sup +}) and mtDNA-depleted ({rho}{sup 0}) human-hamster hybrid cells to investigate mitochondrial effects on the genotoxicity in bystander effect through medium transfer experiments. Through the detection of DNA double-strand breaks with {gamma}-H2AX, we found that the fraction of {gamma}-H2AX positive cells changed with time when irradiation conditioned cell medium (ICCM) were harvested. ICCM harvested from irradiated {rho}{sup +} cells at 10 min post-irradiation ({rho}{sup +} ICCM{sub 10min}) caused larger increases of bystander {gamma}-H2AX induction comparing to {rho}{sup 0} ICCM{sub 10min}, which only caused a slight increase of bystander {gamma}-H2AX induction. The {rho}{sup +} ICCM{sub 10min} could also result in the up-regulation of ROS production (increased by 35% at 10 min), while there was no significant increase in cells treated with {rho}{sup 0} ICCM{sub 10min}. We treated cells with dimethyl sulfoxide (DMSO), the scavenger of ROS, and quenched {gamma}-H2AX induction by {rho}{sup +} ICCM. Furthermore, after the medium had been transferred and the cells were continuously cultured for 7 days, we found significantly increased CD59{sup -} gene loci mutation (increased by 45.9%) and delayed cell death in the progeny of {rho}{sup +} ICCM-treated bystander cells. In conclusion, the work presented here suggested that up-regulation of the mitochondria-dependent ROS might be very important in mediating genotoxicity of bystander effects.

Chen Shaopeng [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Zhao Ye; Zhao Guoping [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Han Wei [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Bao Lingzhi [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Yu, K.N., E-mail: peter.yu@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Wu Lijun, E-mail: ljw@ipp.ac.cn [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

2009-06-18

168

Cell protective, ABC triblock polymer-based thermoresponsive hydrogels with ROS-triggered degradation and drug release.  

Science.gov (United States)

A combination of anionic and RAFT polymerization was used to synthesize an ABC triblock polymer poly[(propylenesulfide)-block-(N,N-dimethylacrylamide)-block-(N-isopropylacrylamide)] (PPS-b-PDMA-b-PNIPAAM) that forms physically cross-linked hydrogels when transitioned from ambient to physiologic temperature and that incorporates mechanisms for reactive oxygen species (ROS) triggered degradation and drug release. At ambient temperature (25 °C), PPS-b-PDMA-b-PNIPAAM assembled into 66 ± 32 nm micelles comprising a hydrophobic PPS core and PNIPAAM on the outer corona. Upon heating to physiologic temperature (37 °C), which exceeds the lower critical solution temperature (LCST) of PNIPAAM, micelle solutions (at ?2.5 wt %) sharply transitioned into stable, hydrated gels. Temperature-dependent rheology indicated that the equilibrium storage moduli (G') of hydrogels at 2.5, 5.0, and 7.5 wt % were 20, 380, and 850 Pa, respectively. The PPS-b-PDMA-b-PNIPAAM micelles were preloaded with the model drug Nile red, and the resulting hydrogels demonstrated ROS-dependent drug release. Likewise, exposure to the peroxynitrite generator SIN-1 degraded the mechanical properties of the hydrogels. The hydrogels were cytocompatible in vitro and were demonstrated to have utility for cell encapsulation and delivery. These hydrogels also possessed inherent cell-protective properties and reduced ROS-mediated cellular death in vitro. Subcutaneously injected PPS-b-PDMA-b-PNIPAAM polymer solutions formed stable hydrogels that sustained local release of the model drug Nile red for 14 days in vivo. These collective data demonstrate the potential use of PPS-b-PDMA-b-PNIPAAM as an injectable, cyto-protective hydrogel that overcomes conventional PNIPAAM hydrogel limitations such as syneresis, lack of degradability, and lack of inherent drug loading and environmentally responsive release mechanisms. PMID:25254509

Gupta, Mukesh K; Martin, John R; Werfel, Thomas A; Shen, Tianwei; Page, Jonathan M; Duvall, Craig L

2014-10-22

169

Effect of Methyl Jasmonate on antioxidative enzyme activities and on the contents of ROS and H2O2 in Ricinus communis leaves  

Directory of Open Access Journals (Sweden)

Full Text Available Jasmonates are a class of plant hormones that mediate various aspects in gene and metabolic regulation, defense, stress responses, reproduction and, possibly, communication. Oxidative stress stimulates synthesis of antioxidant metabolites and enhances antioxidant enzyme activities that could protect plant tissues. The aim of this study was to verify the effects of methyl jasmonate (JAME treatment on the reactive oxygen species (ROS and on the activities of H2O2 scavenging enzymes, such as superoxide dismutase (SOD; EC 1.15.1.1, catalase (CAT; EC 1.11.1.6, ascorbate peroxidase (APX EC; 1.11.1.1, and guaiacol peroxidase (GPX; EC 1.11.1.7 in Ricinus communis leaves. The activity of CAT and GPX was transient while SOD activity decreased and APX increased after treatment with JAME. In addition, JAME exposure induced ROS accumulation.

Alexandra Martins dos Santos Soares

2010-01-01

170

Effect of Methyl Jasmonate on antioxidative enzyme activities and on the contents of ROS and H2O2 in Ricinus communis leaves  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Jasmonates are a class of plant hormones that mediate various aspects in gene and metabolic regulation, defense, stress responses, reproduction and, possibly, communication. Oxidative stress stimulates synthesis of antioxidant metabolites and enhances antioxidant enzyme activities that could protect [...] plant tissues. The aim of this study was to verify the effects of methyl jasmonate (JAME) treatment on the reactive oxygen species (ROS) and on the activities of H2O2 scavenging enzymes, such as superoxide dismutase (SOD; EC 1.15.1.1), catalase (CAT; EC 1.11.1.6), ascorbate peroxidase (APX EC; 1.11.1.1), and guaiacol peroxidase (GPX; EC 1.11.1.7) in Ricinus communis leaves. The activity of CAT and GPX was transient while SOD activity decreased and APX increased after treatment with JAME. In addition, JAME exposure induced ROS accumulation.

Alexandra Martins dos Santos, Soares; Thiago Freitas de, Souza; Tânia, Jacinto; Olga Lima Tavares, Machado.

171

Bioenergetic pathways in tumor mitochondria as targets for cancer therapy and the importance of the ROS-induced apoptotic trigger.  

Science.gov (United States)

Mitochondria are emerging as idealized targets for anti-cancer drugs. One reason for this is that although these organelles are inherent to all cells, drugs are being developed that selectively target the mitochondria of malignant cells without adversely affecting those of normal cells. Such anti-cancer drugs destabilize cancer cell mitochondria and these compounds are referred to as mitocans, classified into several groups according to their mode of action and the location or nature of their specific drug targets. Many mitocans selectively interfere with the bioenergetic functions of cancer cell mitochondria, causing major disruptions often associated with ensuing overloads in ROS production leading to the induction of the intrinsic apoptotic pathway. This in-depth review describes the bases for the bioenergetic differences found between normal and cancer cell mitochondria, focussing on those essential changes occurring during malignancy that clinically may provide the most effective targets for mitocan development. A common theme emerging is that mitochondrially mediated ROS activation as a trigger for apoptosis offers a powerful basis for cancer therapy. Continued research in this area is likely to identify increasing numbers of novel agents that should prove highly effective against a variety of cancers with preferential toxicity towards malignant tissue, circumventing tumor resistance to the other more established therapeutic anti-cancer approaches. PMID:20026172

Ralph, Stephen J; Rodríguez-Enríquez, Sara; Neuzil, Jiri; Moreno-Sánchez, Rafael

2010-02-01

172

Radiation medicine could ROS and RNOS produced by low-level radiation exposure cause different pathways of cell responses  

International Nuclear Information System (INIS)

Human population is constantly exposed to low levels of natural ionizing radiation, primarily from environmental sources, and to higher levels from occupational sources, medical therapy and other human-mediated events. Ionizing radiation acts producing a variety of free radicals and chemical products, the most interesting being reactive oxygen species (ROS) and reactive nitrogen oxide species (RNOS) due to their direct effects on cell-cycle redox system. Exposure to low-level ionizing radiation could have beneficial biological effects to opposite to harmful ones predicted by linear no-threshold (LNT) model. Beside hormesis, these effects include immune and adaptive responses. International Commission on Radiological Protection (ICRP) considers that all these responses are real but they most likely modify the shape of the dose-response curve rather than confirming a threshold (1). The Main Commission of ICRP is now proposing a revised, simpler, approach based on the concept termed 'controllable dose'. Understanding of the cellular mechanisms of ionizing radiation effects is increasingly important to assess biological risks. Together with epidemiological evidence on low dose exposure effects these data represent the basis for exact definition of what ICRP concept about .controllable dose.... could really mean. In this paper we will summarize evidence that both ROS and RNOS function in two discrete fashions: high amount are toxic and low have physiological regulatory rol and low have physiological regulatory role which is molecular base for adaptive responses and hormesis effect at low-level radiation exposure. (authors)

173

Antifungal activity of ZnO nanoparticles-the role of ROS mediated cell injury  

Energy Technology Data Exchange (ETDEWEB)

Metal oxide nanoparticles have marked antibacterial activity. The toxic effect of these nanoparticles, such as those comprised of ZnO, has been found to occur due to an interaction of the nanoparticle surface with water, and to increase with a decrease in particle size. In the present study, we tested the ability of ZnO nanoparticles to affect the viability of the pathogenic yeast, Candida albicans (C. albicans). A concentration-dependent effect of ZnO on the viability of C. albicans was observed. The minimal fungicidal concentration of ZnO was found to be 0.1 mg ml{sup -1} ZnO; this concentration caused an inhibition of over 95% in the growth of C. albicans. ZnO nanoparticles also inhibited the growth of C. albicans when it was added at the logarithmic phase of growth. Addition of histidine (a quencher of hydroxyl radicals and singlet oxygen) caused reduction in the effect of ZnO on C. albicans depending on its concentration. An almost complete elimination of the antimycotic effect was achieved following addition of 5 mM of histidine. Exciting the ZnO by visible light increased the yeast cell death. The effects of histidine suggest the involvement of reactive oxygen species, including hydroxyl radicals and singlet oxygen, in cell death. In light of the above results it appears that metal oxide nanoparticles may provide a novel family of fungicidal compounds.

Lipovsky, Anat; Gedanken, Aharon [Department of Chemistry, Kanbar Laboratory for Nanomaterials, Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 52900 (Israel); Nitzan, Yeshayahu [Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900 (Israel); Lubart, Rachel [Department of Chemistry, Bar-Ilan University, Ramat-Gan (Israel)

2011-03-11

174

ROS-mediated upregulation of Noxa overcomes chemoresistance in chronic lymphocytic leukemia  

OpenAIRE

In recent years considerable progress has been made in treatment strategies for chronic lymphocytic leukemia (CLL). However, the disease remains incurable because of the development of chemoresistance. Strategies to overcome resistance mechanisms are therefore highly needed. At least two mechanisms contribute to the development of resistance to drugs; acquired mutations resulting in a dysfunctional p53 response and shifts in the balance between apoptosis-regulating proteins. Platinum-based co...

Tonino, Sh; Laar, J.; Oers, Mh; Wang, Jy; Eldering, E.; Kater, Ap

2010-01-01

175

The protective role of antioxidants in the defence against ROS/RNS-mediated environmental pollution.  

Science.gov (United States)

Overproduction of reactive oxygen and nitrogen species can result from exposure to environmental pollutants, such as ionising and nonionising radiation, ultraviolet radiation, elevated concentrations of ozone, nitrogen oxides, sulphur dioxide, cigarette smoke, asbestos, particulate matter, pesticides, dioxins and furans, polycyclic aromatic hydrocarbons, and many other compounds present in the environment. It appears that increased oxidative/nitrosative stress is often neglected mechanism by which environmental pollutants affect human health. Oxidation of and oxidative damage to cellular components and biomolecules have been suggested to be involved in the aetiology of several chronic diseases, including cancer, cardiovascular disease, cataracts, age-related macular degeneration, and aging. Several studies have demonstrated that the human body can alleviate oxidative stress using exogenous antioxidants. However, not all dietary antioxidant supplements display protective effects, for example, ?-carotene for lung cancer prevention in smokers or tocopherols for photooxidative stress. In this review, we explore the increases in oxidative stress caused by exposure to environmental pollutants and the protective effects of antioxidants. PMID:25140198

Poljšak, Borut; Fink, Rok

2014-01-01

176

The Protective Role of Antioxidants in the Defence against ROS/RNS-Mediated Environmental Pollution  

OpenAIRE

Overproduction of reactive oxygen and nitrogen species can result from exposure to environmental pollutants, such as ionising and nonionising radiation, ultraviolet radiation, elevated concentrations of ozone, nitrogen oxides, sulphur dioxide, cigarette smoke, asbestos, particulate matter, pesticides, dioxins and furans, polycyclic aromatic hydrocarbons, and many other compounds present in the environment. It appears that increased oxidative/nitrosative stress is often neglected mechanism by ...

Ak, Borut Polj X.; Rok Fink

2014-01-01

177

Training Effects on ROS Production Determined by Electron Paramagnetic Resonance in Master Swimmers  

Science.gov (United States)

Acute exercise induces an increase in Reactive Oxygen Species (ROS) production dependent on exercise intensity with highest ROS amount generated by strenuous exercise. However, chronic repetition of exercise, that is, exercise training, may reduce exercise-induced oxidative stress. Aim of this study was to evaluate the effects of 6-weeks high-intensity discontinuous training (HIDT), characterized by repeated variations of intensity and changes of redox potential, on ROS production and antioxidant capacity in sixteen master swimmers. Time course changes of ROS generation were assessed by Electron Paramagnetic Resonance in capillary blood by a microinvasive approach. An incremental arm-ergometer exercise (IE) until exhaustion was carried out at both before (PRE) and after (POST) training (Trg) period. A significant (P < 0.01) increase of ROS production from REST to the END of IE in PRE Trg (2.82 ± 0.66 versus 3.28 ± 0.66?µmol·min?1) was observed. HIDT increased peak oxygen consumption (36.1 ± 4.3 versus 40.6 ± 5.7?mL·kg?1·min?1 PRE and POST Trg, resp.) and the antioxidant capacity (+13%) while it significantly decreased the ROS production both at REST (?20%) and after IE (?25%). The observed link between ROS production, adaptive antioxidant defense mechanisms, and peak oxygen consumption provides new insight into the correlation between ROS response pathways and muscle metabolic function.

Mrakic-Sposta, Simona; Gussoni, Maristella; Porcelli, Simone; Pugliese, Lorenzo; Pavei, Gaspare; Bellistri, Giuseppe; Montorsi, Michela; Tacchini, Philippe; Vezzoli, Alessandra

2015-01-01

178

Free radicals mediate systemic acquired resistance.  

Science.gov (United States)

Systemic acquired resistance (SAR) is a form of resistance that protects plants against a broad spectrum of secondary infections. However, exploiting SAR for the protection of agriculturally important plants warrants a thorough investigation of the mutual interrelationships among the various signals that mediate SAR. Here, we show that nitric oxide (NO) and reactive oxygen species (ROS) serve as inducers of SAR in a concentration-dependent manner. Thus, genetic mutations that either inhibit NO/ROS production or increase NO accumulation (e.g., a mutation in S-nitrosoglutathione reductase [GSNOR]) abrogate SAR. Different ROS function additively to generate the fatty-acid-derived azelaic acid (AzA), which in turn induces production of the SAR inducer glycerol-3-phosphate (G3P). Notably, this NO/ROS?AzA?G3P-induced signaling functions in parallel with salicylic acid-derived signaling. We propose that the parallel operation of NO/ROS and SA pathways facilitates coordinated regulation in order to ensure optimal induction of SAR. PMID:24726369

Wang, Caixia; El-Shetehy, Mohamed; Shine, M B; Yu, Keshun; Navarre, Duroy; Wendehenne, David; Kachroo, Aardra; Kachroo, Pradeep

2014-04-24

179

Free Radicals Mediate Systemic Acquired Resistance  

Directory of Open Access Journals (Sweden)

Full Text Available Systemic acquired resistance (SAR is a form of resistance that protects plants against a broad spectrum of secondary infections. However, exploiting SAR for the protection of agriculturally important plants warrants a thorough investigation of the mutual interrelationships among the various signals that mediate SAR. Here, we show that nitric oxide (NO and reactive oxygen species (ROS serve as inducers of SAR in a concentration-dependent manner. Thus, genetic mutations that either inhibit NO/ROS production or increase NO accumulation (e.g., a mutation in S-nitrosoglutathione reductase [GSNOR] abrogate SAR. Different ROS function additively to generate the fatty-acid-derived azelaic acid (AzA, which in turn induces production of the SAR inducer glycerol-3-phosphate (G3P. Notably, this NO/ROS?AzA?G3P-induced signaling functions in parallel with salicylic acid-derived signaling. We propose that the parallel operation of NO/ROS and SA pathways facilitates coordinated regulation in order to ensure optimal induction of SAR.

Caixia Wang

2014-04-01

180

Temporal dynamics of ROS biogenesis under simulated solar radiation in the cyanobacterium Anabaena variabilis PCC 7937.  

Science.gov (United States)

We studied the temporal generation of reactive oxygen species (ROS) in the cyanobacterium Anabaena variabilis PCC 7937 under simulated solar radiation using WG 280, WG 295, WG 305, WG 320, WG 335, WG 345, and GG 400 nm cut-off filters to find out the minimum exposure time and most effective region of the solar spectrum inducing highest level of ROS. There was no significant generation of ROS in all treatments in comparison to the samples kept in the dark during the first 8 h of exposure; however, after 12 h of exposure, ROS were significantly generated in samples covered with 305, 295, or 280 nm cut-off filters. In contrast with ROS, the fragmentation of filaments was predominantly seen in 280 nm cut-off filter covered samples after 12 h of exposure. After 24 h of exposure, ROS levels were significantly higher in all samples than in the dark; however, the ROS signals were more pronounced in 320, 305, 295, or 280 nm cut-off filter covered samples. In contrast, the length of filaments was reduced in 305, 295, or 280 nm cut-off filter covered samples after 24 h of exposure. Thus, fragmentation of the filament was induced by all wavelengths of the UV-B region contrary to the UV-A region where only shorter wavelengths were able to induce the fragmentation. In contrast, ROS were generated by all wavelengths of the solar spectrum after 24 h of exposure; however, shorter wavelengths of both the UV-A and the UV-B regions were more effective in generating ROS in comparison to their higher wavelengths and photosynthetic active radiation (PAR). Moreover, lower wavelengths of UV-B were more efficient than the lower wavelengths of the UV-A radiation. Findings from this study suggest that certain threshold levels of ROS are required to induce the fragmentation of filaments. PMID:24633292

Singh, Shailendra P; Rastogi, Rajesh P; Häder, Donat-P; Sinha, Rajeshwar P

2014-09-01

181

Selenite-induced cell death in Saccharomyces cerevisiae: protective role of glutaredoxins  

OpenAIRE

Unlike in higher organisms, selenium is not essential for growth in Saccharomyces cerevisiae. In this species, it causes toxic effects at high concentrations. In the present study, we show that when supplied as selenite to yeast cultures growing under fermentative metabolism, its effects can be dissected into two death phases. From the time of initial treatment, it causes loss of membrane integrity and genotoxicity. Both effects occur at higher levels in mutants lacking Grx1p and Grx2p than i...

Izquierdo A?lvarez, Alicia; Casas Herranz, Celia; Herrero Perpin?a?n, Enrique

2010-01-01

182

ICB3E induces iNOS expression by ROS-dependent JNK and ERK activation for apoptosis of leukemic cells.  

Science.gov (United States)

The role of c-Jun N terminal Kinase (JNK) has been well documented in various cellular stresses where it leads to cell death. Similarly, extracellular signal-regulated kinase (ERK) which was identified as a signalling molecule for survival pathway has been shown recently to be involved in apoptosis also. Recently we reported that ICB3E, a synthetic analogue of Piper betle leaf-derived apoptosis-inducing agent hydroxychavicol (HCH), possesses anti-chronic myeloid leukemia (CML) acitivity in vitro and in vivo without insight on mechanism of action. Here we report that ICB3E is three to four times more potent than HCH in inducing apoptosis of leukemic cells without having appreciable effects on normal human peripheral blood mononuclear cells, mouse fibroblast cell line NIH3T3 and monkey kidney epithelial cell line Vero. ICB3E causes early accumulation of mitochondria-derived reactive oxygen species (ROS) in K562 cells. Unlike HCH, ICB3E treatment caused ROS dependent activation of both JNK, ERK and induced the expression of iNOS leading to generation of nitric oxide (NO). This causes cleavage of caspase 9, 3 and PARP leading to apoptosis. Lack of cleavage of caspase 8 and inability of blocking chimera antibody to DR5 or neutralizing antibody to Fas to reverse ICB3E-mediated apoptosis suggest the involvement of only intrinsic pathway. Our data reveal a novel ROS-dependent JNK/ERK-mediated iNOS activation pathway which leads to NO mediated cell death by ICB3E. PMID:22252531

Biswas, Nabendu; Mahato, Sanjit K; Chowdhury, Avik Acharya; Chaudhuri, Jaydeep; Manna, Anirban; Vinayagam, Jayaraman; Chatterjee, Sourav; Jaisankar, Parasuraman; Chaudhuri, Utpal; Bandyopadhyay, Santu

2012-06-01

183

Toxaphene, but not beryllium, induces human neutrophil chemotaxis and apoptosis via reactive oxygen species (ROS): involvement of caspases and ROS in the degradation of cytoskeletal proteins.  

Science.gov (United States)

Chemicals of environmental concern are known to alter the immune system. Recent data indicate that some contaminants possess proinflammatory properties by activating neutrophils, an area of research that is still poorly investigated. We have previously documented that toxaphene activates human neutrophils to produce reactive oxygen species (ROS) and accelerates apoptosis by a yet unknown mechanism. In this study, we found that toxaphene induces another neutrophil function, chemotaxis. Furthermore, we found that toxaphene induces both chemotaxis and apoptosis via a ROS-dependent mechanism, since these responses were blocked by the addition of catalase to the culture. In addition, toxaphene was found to induce the degradation of the cytoskeletal proteins gelsolin, paxillin, and vimentin during apoptosis, and this was reversed by the addition of z-VAD-FMK (caspase inhibitor) or catalase, demonstrating the importance of caspases and ROS in this process. In contrast to toxaphene, we found that beryllium does not induce superoxide production, and, this correlates with its inability to induce chemotaxis and apoptosis. We conclude that toxaphene induces chemotaxis and apoptosis via ROS and that caspases and ROS are involved in the degradation of cytoskeletal proteins. PMID:12139946

Lavastre, Valérie; Roberge, Charles J; Pelletier, Martin; Gauthier, Marc; Girard, Denis

2002-07-01

184

ROS generation and multiple forms of mammalian mitochondrial glycerol-3-phosphate dehydrogenase.  

Science.gov (United States)

Overproduction of reactive oxygen species (ROS) has been implicated in a range of pathologies. Mitochondrial flavin dehydrogenases glycerol-3-phosphate dehydrogenase (mGPDH) and succinate dehydrogenase (SDH) represent important ROS source, but the mechanism of electron leak is still poorly understood. To investigate the ROS production by the isolated dehydrogenases, we used brown adipose tissue mitochondria solubilized by digitonin as a model. Enzyme activity measurements and hydrogen peroxide production studies by Amplex Red fluorescence, and luminol luminescence in combination with oxygraphy revealed flavin as the most likely source of electron leak in SDH under in vivo conditions, while we propose coenzyme Q as the site of ROS production in the case of mGPDH. Distinct mechanism of ROS production by the two dehydrogenases is also apparent from induction of ROS generation by ferricyanide which is unique for mGPDH. Furthermore, using native electrophoretic systems, we demonstrated that mGPDH associates into homooligomers as well as high molecular weight supercomplexes, which represent native forms of mGPDH in the membrane. By this approach, we also directly demonstrated that isolated mGPDH itself as well as its supramolecular assemblies are all capable of ROS production. PMID:23999537

Mrá?ek, Tomáš; Holzerová, Eliška; Drahota, Zden?k; Ková?ová, Nikola; Vrbacký, Marek; Ješina, Pavel; Houšt?k, Josef

2014-01-01

185

TOR Complex 2-Ypk1 Signaling Maintains Sphingolipid Homeostasis by Sensing and Regulating ROS Accumulation  

Directory of Open Access Journals (Sweden)

Full Text Available Reactive oxygen species (ROS are produced during normal metabolism and can function as signaling molecules. However, ROS at elevated levels can damage cells. Here, we identify the conserved target of rapamycin complex 2 (TORC2/Ypk1 signaling module as an important regulator of ROS in the model eukaryotic organism, S. cerevisiae. We show that TORC2/Ypk1 suppresses ROS produced both by mitochondria as well as by nonmitochondrial sources, including changes in acidification of the vacuole. Furthermore, we link vacuole-related ROS to sphingolipids, essential components of cellular membranes, whose synthesis is also controlled by TORC2/Ypk1 signaling. In total, our data reveal that TORC2/Ypk1 act within a homeostatic feedback loop to maintain sphingolipid levels and that ROS are a critical regulatory signal within this system. Thus, ROS sensing and signaling by TORC2/Ypk1 play a central physiological role in sphingolipid biosynthesis and in the maintenance of cell growth and viability.

Brad J. Niles

2014-02-01

186

TiO{sub 2} nanoparticle-induced ROS correlates with modulated immune cell function  

Energy Technology Data Exchange (ETDEWEB)

Design of non-toxic nanoparticles will be greatly facilitated by understanding the nanoparticle-cell interaction mechanism on a cell function level. Mast cells are important cells for the immune system's first line of defense, and we can utilize their exocytotic behavior as a model cellular function as it is a conserved process across cell types and species. Perturbations in exocytosis can also have implications for whole organism health. One proposed mode of toxicity is nanoparticle-induced reactive oxygen species (ROS), particularly for titanium dioxide (TiO{sub 2}) nanoparticles. Herein, we have correlated changes in ROS with the perturbation of the critical cell function of exocytosis, using UV light to induce greater levels of ROS in TiO{sub 2} exposed cells. The primary culture mouse peritoneal mast cells (MPMCs) were exposed to varying concentrations of TiO{sub 2} nanoparticles for 24 h. ROS content was determined using 2,7-dihydrodichlorofluorescein diacetate (DCFDA). Cellular viability was determined with the MTT and Trypan blue assays, and exocytosis was measured by the analytical electrochemistry technique of carbon-fiber microelectrode amperometry. MPMCs exposed to TiO{sub 2} nanoparticles experienced a dose-dependent increase in total ROS content. While there was minimal impact of ROS on cellular viability, there is a correlation between ROS amount and exocytosis perturbation. As nanoparticle-induced ROS increases, there is a significant decrease (45 %) in the number of serotonin molecules being released during exocytosis, increase (26 %) in the amount of time for each exocytotic granule to release, and decrease (28 %) in the efficiency of granule trafficking and docking. This is the first evidence that nanoparticle-induced ROS correlates with chemical messenger molecule secretion, possibly making a critical connection between functional impairment and mechanisms contributing to that impairment.

Maurer-Jones, Melissa A.; Christenson, Jenna R.; Haynes, Christy L., E-mail: chaynes@umn.edu [University of Minnesota, Department of Chemistry (United States)

2012-12-15

187

Surface functionalization of titanium dioxide nanoparticles: Photo-stability and reactive oxygen species (ROS) generation  

Science.gov (United States)

Metal oxide nanoparticles are becoming increasingly prevalent in society for applications of sunscreens, cosmetics, paints, biomedical imaging, and photovoltaics. Due to the increased surface area to volume ratio of nanoparticles compared to bulk materials, it is important to know the health and safety impacts of these materials. One mechanism of toxicity of nominally "safe" materials such as TiO 2 is through the photocatalytic generation of reactive oxygen species (ROS). ROS production and ligand degradation can affect the bioavailability of these particles in aqueous organisms. We have investigated ROS generation by functionalized TiO2 nanoparticles and its influence on aggregation and bioavailability and toxicity to zebrafish embryos/larvae. For these studies we investigated anatase TiO2 nanoparticles. For application purposes and solution stability, the TiO2 nanoparticles were functionalized with a variety of ligands such as citrate, 3,4-dihydroxybenzaldehyde, and ascorbate. We quantitatively examined the amount of ROS produced in aqueous solution using fluorescent probes and see that more ROS is produced under UV light than in the dark control. Our measurements show that TiO2 toxicity reaches a maximum for nanoparticles with smaller diameters, and is correlated with surface area dependent changes in ROS generation. In an effort to reduce toxicity through control of the surface and surface ligands, we synthesized anatase nanoparticles of different sizes, functionalized them with different ligands, and examined the resulting ROS generation and ligand stability. Using a modular ligand containing a hydrophobic inner region and a hydrophilic outer region, we synthesized water-stable nanoparticles, via two different chemical reactions, having much-reduced ROS generation and thus reduced toxicity. These results suggest new strategies for making safer nanoparticles while still retaining their desired properties. We also examine the degradation of the different ligands on the surface of the particles using XPS and FTIR. The combination of ROS production and ligand degradation can affect the bioavailability of these particles in aqueous species.

Louis, Kacie M.

188

Measurements of UV-generated free radicals/reactive oxygen species (ROS) in skin  

Science.gov (United States)

Free radicals/reactive oxygen species (ROS) generated in skin by UV irradiation were measured by electron spin resonance (ESR). To increase the sensitivity of measurement the short life free radicals/ROS were scavenged and accumulated by using the nitroxyl probe 3-carboxy-2,2,5,5-tetrametylpyrrolidine-1-oxyl (PCA). The spatial distribution of free radicals/ROS measured in pig skin biopsies with ESR imaging after UV irradiation corresponds to the intensity decay of irradiance in the depth of the skin. The main part of free radicals/ROS were generated by UVA (320-400 nm) so that the spatial distribution of free radicals reaches up to the lower side of the dermis. In vivo measurements on human skin were performed with a L-band ESR spectrometer and a surface coil integrating the signal intensities from all skin layers to get a sufficient signal amplitude. Using this experimental arrangement the protection of UVB and UVA/B filter against the generation of free radicals/ROS in skin were measured. The protection against ROS and the repair of damages caused by them can be realized with active antioxidants characterized by a high antioxidative power (AP). The effect of UV filter and antioxidants corresponding to their protection against free radicals/ROS in skin generated by UVAB irradiation can be quantified by the new radical sun protection factor (RSF). The RSF indicates the increase of time for staying in the sun to generate the same number of free radicals/ROS in the skin like for the unprotected skin. Regarding the amount of generated free radicals/ROS in skin as an biophysical endpoint the RSF characterizes both the protection against UVB and UVA radiation.

Herrling, Th.; Jung, K.; Fuchs, J.

2006-03-01

189

Reactive oxygen species (ROS) production by amoebocytes of Asterias rubens (Echinodermata).  

Science.gov (United States)

An adapted peroxidase, luminol-enhanced chemiluminescence method in an EDTA-free, Ca++-containing medium is described and used to characterise reactive oxygen species (ROS) production by starfish immunocytes using a standard microplate reader luminometer. ROS production was stimulated by direct interaction of immunocytes with bacteria or bacterial wall components, but not by the soluble stimulant PMA nor the lectin concanavalin A. Produced ROS detected by this method are apparently superoxide anions, hydrogen peroxide and peroxynitrite. Comparison with other chemiluminescence methods indicates that the described method is the only one to detect the stimulation of starfish immunocytes by the Gram-positive bacteria, Micrococcus luteus, a fact that questions previous reports indicating a lack of stimulation by pathogens. The adapted method provides a rapid determination of the overall ROS production, which is suitable for both disease control and immunotoxicological studies in echinoderms. PMID:11931015

Coteur, Geoffroy; Warnau, Michel; Jangoux, Michel; Dubois, Philippe

2002-03-01

190

RosUkrEnergo lubas piiluda rahamasina hämarasse sisemusse / Krister Paris  

Index Scriptorium Estoniae

Ukrainasse gaasi vahendava RosUkrEnergo omanikke hoiti viimase ajani saladuses, nüüd on omanikering avalikustatud. Firmat seostatakse Venemaa väidetava esikurjategijaga. Briti mõttekoda Global Witness kutsub oma raportis Ukraina valitsust firmat põhjalikult uurima. Lisa: Salapärane miljardär ja gaasimängud

Paris, Krister

2006-01-01

191

Rhodiola crenulata and Its Bioactive Components, Salidroside and Tyrosol, Reverse the Hypoxia-Induced Reduction of Plasma-Membrane-Associated Na,K-ATPase Expression via Inhibition of ROS-AMPK-PKC? Pathway  

OpenAIRE

Exposure to hypoxia leads to impaired pulmonary sodium transport, which is associated with Na,K-ATPase dysfunction in the alveolar epithelium. The present study is designed to examine the effect and mechanism of Rhodiola crenulata extract (RCE) and its bioactive components on hypoxia-mediated Na,K-ATPase endocytosis. A549 cells were exposed to hypoxia in the presence or absence of RCE, salidroside, or tyrosol. The generation of intracellular ROS was measured by using the fluorescent probe DCF...

Lee, Shih-yu; Shi, Li-shian; Chu, Hsin; Li, Min-hui; Ho, Cheng-wen; Lai, Feng-yi; Huang, Chih-yang; Chang, Tsu-chung

2013-01-01

192

Reactive oxygen and nitrogen intermediates contribute to Haemophilus somnus lipooligosaccharide-mediated apoptosis of bovine endothelial cells.  

Science.gov (United States)

Although Haemophilus somnus causes septicemia and vasculitis in cattle, relatively little is known about how H. somnus affects endothelial cells in vitro. We previously reported that H. somnus lipooligosaccharide (LOS)-induced activation of caspases-3, -8 and -9, and apoptosis of bovine pulmonary artery endothelial cells (BPAEC) in vitro. Previous reports indicate that the generation of reactive oxygen species (ROS) or reactive nitrogen intermediates (RNI) can contribute to the induction of apoptosis. In the present study, we sought to determine whether ROS and RNI are involved in LOS-mediated apoptosis of BPAEC. We found that H. somnus LOS induced the generation of ROS in BPAEC, which was blocked by pretreatment with membrane permeable ROS scavengers, such as dimethylsulfoxide (DMSO) and allopurinol (AP). Addition of DMSO or AP significantly reduced H. somnus LOS-mediated caspase-3 activation. Addition of membrane impermeable ROS scavengers (e.g. catalase and superoxide dismutase), failed to block LOS-mediated caspase-3 activation, suggesting a role for intracellular generation of ROS in LOS-induced apoptosis of BPAEC. Addition of N(G)-nitro-L-arginine methyl ester (L-NAME) or aminoguanidine, which are selective inhibitors of nitric oxide synthase, blocked NO release and significantly reduced caspase-3 activation in LOS treated BPAEC. These data suggest H. somnus LOS triggers endogenous ROS and RNI production by endothelial cells, which contributes to apoptosis. PMID:14741139

Sylte, Matt J; Inzana, Thomas J; Czuprynski, Charles J

2004-02-01

193

Pogostemon cablin as ROS Scavenger in Oxidant-induced Cell Death of Human Neuroglioma Cells  

OpenAIRE

Reactive oxygen species (ROS) have been implicated in the pathogenesis of a wide range of acute and long-term neurodegenerative diseases. This study was undertaken to examine the efficacy of Pogostemon cablin, a well-known herb in Korean traditional medicine, on ROS-induced brain cell injury. Pogostemon cablin effectively protected human neuroglioma cell line A172 against both the necrotic and apoptotic cell death induced by hydrogen peroxide (H2O2). The effect of Pogostemon cablin was dose d...

Young Kyun Kim; Su In Cho; Su Jin Cho; Bu-Yeo Kim; Hyung Woo Kim

2008-01-01

194

Involvement of NO and ROS in sulfur dioxide induced guard cells apoptosis in Tagetes erecta.  

Science.gov (United States)

Both nitric oxide (NO) and reactive oxygen species (ROS) are very important signal molecules, but the roles they play in signal transduction of sulfur dioxide (SO2) induced toxicities on ornamental plants is not clear. In this study, the functions of NO and ROS in SO2-induced death of lower epidermal guard cells in ornamental plant Tagetes erecta were investigated. The results showed that SO2 derivatives (0.4-4.0mmolL(-1) of final concentrations) could reduce the guard cells' viability and increase their death rates in a dose-dependent manner. Meanwhile, the significant increase of cellular NO, ROS, and Ca(2+) levels (Pinhibitor NaN3; NO synthase inhibitor L-NAME), ROS scavenger (AsA or CAT) or Ca(2+) antagonists (Ca(2+) scavenger EGTA or plasma membrane Ca(2+) channel blocker LaCl3) can effectively block SO2-induced guard cells death and corresponding increase of NO, ROS and Ca(2+) levels. In addition, addition of L-NAME or AsA in 2.0mmolL(-1) of SO2 derivatives led to significant decrease in the levels of NO, ROS and Ca(2+), whereas addition of LaCl3 in them just resulted in the decrease of Ca(2+) levels, hardly making effects on NO and ROS levels. It was concluded that NO and ROS were involved in the apoptosis induced by SO2 in T. erecta, which regulated the cell apoptosis at the upstream of Ca(2+). PMID:25645141

Wei, Aili; Fu, Baocun; Wang, Yunshan; Zhai, Xiaoyan; Xin, Xiaojing; Zhang, Chao; Cao, Dongmei; Zhang, Xiaobing

2015-04-01

195

Arabidopsis GRI is involved in the regulation of cell death induced by extracellular ROS  

OpenAIRE

Reactive oxygen species (ROS) have important functions in plant stress responses and development. In plants, ozone and pathogen infection induce an extracellular oxidative burst that is involved in the regulation of cell death. However, very little is known about how plants can perceive ROS and regulate the initiation and the containment of cell death. We have identified an Arabidopsis thaliana protein, GRIM REAPER (GRI), that is involved in the regulation of cell death induced by extracellul...

Wrzaczek, Michael; Brosche?, Mikael; Kollist, Hannes; Kangasja?rvi, Jaakko

2009-01-01

196

HIV protease inhibitors elicit volume-sensitive Cl? current in cardiac myocytes via mitochondrial ROS  

OpenAIRE

HIV protease inhibitors (HIV PI) reduce morbidity and mortality of HIV infection but cause multiple untoward effects. Because certain HIV PI evoke production of reactive oxygen species (ROS) and volume-sensitive Cl? current (ICl,swell) is activated by ROS, we tested whether HIV PI stimulate ICl,swell in ventricular myocytes. Ritonavir and lopinavir elicited outwardly-rectifying Cl? currents under isosmotic conditions that were abolished by the selective ICl,swell-blocker DCPIB. In contras...

Deng, Wu; Baki, Lia; Yin, Jun; Zhou, Huiping; Baumgarten, Clive M.

2010-01-01

197

Desferoxamine and ethyl-3,4-dihydroxybenzoate protect myocardium by activating NOS and generating mitochondrial ROS.  

Science.gov (United States)

Protection from a prolyl hydroxylase domain-containing enzyme (PHD) inhibitor, desferoxamine (DFO), was recently reported to be dependent on production of reactive oxygen species (ROS). Ischemic preconditioning triggers the protected state by stimulating nitric oxide (NO) production to open mitochondrial ATP-sensitive K+ (mitoK(ATP)) channels, generating ROS required for protection. We tested whether DFO and a second PHD inhibitor, ethyl-3,4-dihydroxybenzoate (EDHB), might have similar mechanisms. EDHB and DFO increased ROS generation by 50-75% (P methyl ester (L-NAME), an NO synthase (NOS) inhibitor; ODQ, a guanylyl cyclase antagonist; and Rp-8-bromoguanosine-3',5'-cyclic monophosphorothioate Rp isomer, a PKG blocker, thus implicating the NO pathway in EDHB's signaling. Glibenclamide, a nonselective K(ATP) channel blocker, or 5-hydroxydecanoate, a selective mitoK(ATP) channel antagonist, also prevented EDHB's ROS production, as did blockade of mitochondrial electron transport with myxothiazol. NOS is activated by Akt. However, neither wortmannin, an inhibitor of phosphatidylinositol-3-kinase, nor Akt inhibitor blocked EDHB-induced ROS generation, indicating that EDHB initiates signaling downstream of Akt. DFO also increased ROS production, and this effect was blocked by ODQ, 5-hydroxydecanoate, and N-(2-mercaptopropionyl)glycine, an ROS scavenger. DFO increased cardiomyocyte production of nitrite, a metabolite of NO, and this effect was blocked by an inhibitor of NOS. DFO also spared ischemic myocardium in intact hearts. This infarct-sparing effect was blocked by ODQ, L-NAME, and N-(2-mercaptopropionyl)glycine. Hence, DFO and EDHB stimulate NO-dependent activation of PKG to open mitoK(ATP) channels and produce ROS, which act as second messengers to trigger entrance into the preconditioned state. PMID:16155105

Philipp, Sebastian; Cui, Lin; Ludolph, Barbara; Kelm, Malte; Schulz, Rainer; Cohen, Michael V; Downey, James M

2006-01-01

198

The role of ROS signaling in cross-tolerance: from model to crop  

OpenAIRE

Reactive oxygen species (ROS) are key signaling molecules produced in response to biotic and abiotic stresses that trigger a variety of plant defense responses. Cross-tolerance, the enhanced ability of a plant to tolerate multiple stresses, has been suggested to result partly from overlap between ROS signaling mechanisms. Cross-tolerance can manifest itself both as a positive genetic correlation between tolerance to different stresses (inherent cross-tolerance), and as the priming of systemic...

Perez, Ilse Barrios; Brown, Patrick J.

2014-01-01

199

A preliminary cyber-physical security assessment of the Robot Operating System (ROS)  

Science.gov (United States)

Over the course of the last few years, the Robot Operating System (ROS) has become a highly popular software framework for robotics research. ROS has a very active developer community and is widely used for robotics research in both academia and government labs. The prevalence and modularity of ROS cause many people to ask the question: "What prevents ROS from being used in commercial or government applications?" One of the main problems that is preventing this increased use of ROS in these applications is the question of characterizing its security (or lack thereof). In the summer of 2012, a crowd sourced cyber-physical security contest was launched at the cyber security conference DEF CON 20 to begin the process of characterizing the security of ROS. A small-scale, car-like robot was configured as a cyber-physical security "honeypot" running ROS. DEFFCON-20 attendees were invited to find exploits and vulnerabilities in the robot while network traffic was collected. The results of this experiment provided some interesting insights and opened up many security questions pertaining to deployed robotic systems. The Federal Aviation Administration is tasked with opening up the civil airspace to commercial drones by September 2015 and driverless cars are already legal for research purposes in a number of states. Given the integration of these robotic devices into our daily lives, the authors pose the following question: "What security exploits can a motivated person with little-to-no experience in cyber security execute, given the wide availability of free cyber security penetration testing tools such as Metasploit?" This research focuses on applying common, low-cost, low-overhead, cyber-attacks on a robot featuring ROS. This work documents the effectiveness of those attacks.

McClean, Jarrod; Stull, Christopher; Farrar, Charles; Mascareñas, David

2013-05-01

200

Detection of ROS1 Gene Rearrangement in Lung Adenocarcinoma: Comparison of IHC, FISH and Real-Time RT-PCR  

Science.gov (United States)

Aims To compare fluorescence in situ hybridization (FISH), immunohistochemistry (IHC) and quantitative real-time reverse transcription-PCR (qRT-PCR) assays for detection of ROS1 fusion in a large number of ROS1-positive lung adenocatcinoma (ADC) patients. Methods Using IHC analysis, sixty lung ADCs including 16 cases with ROS1 protein expression and 44 cases without ROS1 expression were selected for this study. The ROS1 fusion status was examined by FISH and qRT-PCR assay. Results Among 60 cases, 16 (26.7%), 13 (21.7%) and 20 (33.3%) cases were ROS1 positive revealed by IHC, FISH and qRT-PCR, respectively. Using FISH as a standard method for ROS1 fusion detection, the sensitivity and specificity of IHC were 100% and 93.6%, respectively. Three IHC-positive cases, which showed FISH negative, were demonstrated with ROS1 fusion by qRT-PCR analysis. The sensitivity and specificity of qRT-PCR for detection for ROS1 fusion were 100% and 85.1%, respectively. The total concordance rate between IHC and qRT-PCR were 93.3%. Conclusion IHC is a reliable and rapid screening tool in routine pathologic laboratories for the identification of suitable candidates for ROS1-targeted therapy. Some ROS1 IHC-positive but FISH-negative cases did harbor the translocation events and may benefit from crizotinib. PMID:25742289

Guo, Lei; Qiu, Tian; Ling, Yun; Ying, Jianming; Lin, Dongmei

2015-01-01

201

Pogostemon cablin as ROS Scavenger in Oxidant-induced Cell Death of Human Neuroglioma Cells.  

Science.gov (United States)

Reactive oxygen species (ROS) have been implicated in the pathogenesis of a wide range of acute and long-term neurodegenerative diseases. This study was undertaken to examine the efficacy of Pogostemon cablin, a well-known herb in Korean traditional medicine, on ROS-induced brain cell injury. Pogostemon cablin effectively protected human neuroglioma cell line A172 against both the necrotic and apoptotic cell death induced by hydrogen peroxide (H(2)O(2)). The effect of Pogostemon cablin was dose dependent at concentrations ranging from 0.2 to 5?mg ml(-1). Pogostemon cablin significantly prevented depletion of cellular ATP and activation of poly ADP-ribose polymerase induced by H(2)O(2). The preservation of functional integrity of mitochondria upon the treatment of Pogostemon cablin was also confirmed by 3-(4,5-dimethyl-2-thiazyl)-2,5-diphenyl-2-H-tetrazolium bromide assay. Furthermore, Pogostemon cablin significantly prevented H(2)O(2)-induced release of cytochrome c into cytosol. Determination of intracellular ROS showed that Pogostemon cablin might exert its role as a powerful scavenger of intracellular ROS. The present study suggests the beneficial effect of Pogostemon cablin on ROS-induced neuroglial cell injury. The action of Pogostemon cablin as a ROS-scavenger might underlie the mechanism. PMID:18955302

Kim, Hyung Woo; Cho, Su Jin; Kim, Bu-Yeo; Cho, Su In; Kim, Young Kyun

2010-06-01

202

Genetic silencing of Nrf2 enhances X-ROS in dysferlin-deficient muscle  

Directory of Open Access Journals (Sweden)

Full Text Available Oxidative stress is a critical disease modifier in the muscular dystrophies. Recently, we discovered a pathway by which mechanical stretch activates NADPH Oxidase 2 (NoX2 dependent ROS generation (X-ROS. Our work in dystrophic skeletal muscle revealed that X-ROS is excessive in dystrophin-deficient (mdx skeletal muscle and contributes to muscle injury susceptibility, a hallmark of the dystrophic process. We also observed widespread alterations in expression of genes associated with the X-ROS pathway and redox homeostasis in muscles from both Duchenne muscular dystrophy patients and mdx mice. As nuclear factor erythroid 2-related factor 2 (Nrf2 plays an essential role in the transcriptional regulation of genes involved in redox homeostasis, we hypothesized that Nrf2 deficiency may contribute to enhanced X-ROS signaling by reducing redox buffering. To directly test the effect of diminished Nrf2 activity, Nrf2 was genetically silenced in the A/J model of dysferlinopathy - a model with a mild histopathologic and functional phenotype. Nrf2-deficient A/J mice exhibited significant muscle-specific functional deficits, histopathologic abnormalities, and dramatically enhanced X-ROS compared to control A/J and WT mice, both with functional Nrf2. Having identified that reduced Nrf2 activity is a negative disease modifier, we propose that strategies targeting Nrf2 activation may address the generalized reduction in redox homeostasis to halt or slow dystrophic progression.

ChristopherWilliamWard

2014-02-01

203

Cyclosporin A and tacrolimus induce renal Erk1/2 pathway via ROS-induced and metalloproteinase-dependent EGF-receptor signaling.  

Science.gov (United States)

We previously demonstrated that the widely used immunosuppressive drugs cyclosporin A (CsA) and tacrolimus (FK506), independent of immunophilin binding, can activate profibrogenic transforming growth factor ? (TGF?)/Smad signaling cascades in rat renal mesangial cells (MC). Here we report that both peptidyl-prolyl cis/trans isomerase (PPIase) inhibitors activate the extracellular-signaling regulated kinase (ERK) a member of the mitogen activated protein kinase (MAPK) and induce a rapid and transient increase in ERK phosphorylation. The MEK inhibitor U0126, the reactive oxygen species (ROS) scavenger N-acetyl-cysteine (NAC), a cell-permeant superoxide dismutase (SOD) and stigmatellin, an inhibitor of mitochondrial cytochrome bc1 complex strongly attenuated the increase in ERK1/2 phosphorylation triggered by PPIase inhibitors. Moreover, neutralizing antibodies against heparin binding-epidermal growth factor (HB-EGF), and inhibition of the EGF receptor by either small interfering (si)RNA or AG1478, demonstrate that ERK activation by both PPIase inhibitors is mediated via HB-EGF-induced EGF receptor (EGFR) tyrosine kinase activation. The strong inhibitory effects achieved by GM6001 and TAPI-2 furthermore implicate the involvement of a desintegrin and metalloproteinase 17 (ADAM17). Concomitantly, the PPIase inhibitor-induced ADAM17 secretase activity was significantly reduced by SOD and stigmatellin thus suggesting that mitochondrial ROS play a primary role in PPIase inhibitor-induced and ADAM17-mediated HB-EGF shedding. Functionally, both immunosuppressants caused a strong increase in MC proliferation which was similarly impeded when cells were treated in the presence of NAC, TAPI-2 or AG1478, respectively. Our data suggest that CsA and FK506, via ROS-dependent and ADAM17-catalyzed HB-EGF shedding induce the mitogenic ERK1/2 signaling cascade in renal MC. PMID:22100870

Akool, El-Sayed; Gauer, Stefan; Osman, Bashier; Doller, Anke; Schulz, Sebastian; Geiger, Helmut; Pfeilschifter, Josef; Eberhardt, Wolfgang

2012-01-15

204

Isofraxidin, a potent reactive oxygen species (ROS) scavenger, protects human leukemia cells from radiation-induced apoptosis via ROS/mitochondria pathway in p53-independent manner.  

Science.gov (United States)

Ionizing radiation (IR) leads to oxidizing events such as excessive reactive oxygen species (ROS) in the exposed cells, resulting in further oxidative damage to lipids, proteins and DNA. To screen the potential radio-protective drug, the intracellular ROS was measured in irradiated U937 cells pretreated with 80 candidate traditional herbal medicine, respectively. Isofraxidin (IF) was one possible radio-protector in these 80 drugs. This study investigated the radio-protective role of IF, a Coumarin compound, in human leukemia cell lines, for the first time. Results indicate that IF protects against IR-induced apoptosis in U937 cells in the time- and concentration- dependent manner. IF decreases IR-induced intracellular ROS generation, especially hydroxyl radicals formation, inhibits IR-induced mitochondrial membrane potential loss and reduces IR-induced high intracellular Ca(2+) levels regardless of ER stress. IF down-regulates the expression of caspase-3, phospho-JNK, phospho-p38 and activates Bax in mitochondria. IF inhibits cytochrome c release from mitochondria to cytosol. IF also moderates IR-induced Fas externalization and caspase-8 activation. IF also exhibits significant protection against IR-induced cell death in other leukemia cell lines such as Molt-4 cells and HL60 cells regardless of p53. Taken together, the data demonstrate that IF protects leukemia cells from radiation-induced apoptosis via ROS/mitochondria pathway in a p53-independent manner. PMID:24692054

Li, Peng; Zhao, Qing-Li; Wu, Li-Hua; Jawaid, Paras; Jiao, Yu-Fei; Kadowaki, Makoto; Kondo, Takashi

2014-06-01

205

ROS Detoxification and Proinflammatory Cytokines Are Linked by p38 MAPK Signaling in a Model of Mature Astrocyte Activation  

Science.gov (United States)

Astrocytes are the most abundant glial cell in the retinal nerve fiber layer (NFL) and optic nerve head (ONH), and perform essential roles in maintaining retinal ganglion cell (RGC) detoxification and homeostasis. Mature astrocytes are relatively quiescent, but rapidly undergo a phenotypic switch in response to insult, characterized by upregulation of intermediate filament proteins, loss of glutamate buffering, secretion of pro-inflammatory cytokines, and increased antioxidant production. These changes result in both positive and negative influences on RGCs. However, the mechanism regulating these responses is still unclear, and pharmacologic strategies to modulate select aspects of this switch have not been thoroughly explored. Here we describe a system for rapid culture of mature astrocytes from the adult rat retina that remain relatively quiescent, but respond robustly when challenged with oxidative damage, a key pathogenic stress associated with inner retinal injury. When primary astrocytes were exposed to reactive oxygen species (ROS) we consistently observed characteristic changes in activation markers, along with increased expression of detoxifying genes, and secretion of proinflammatory cytokines. This in vitro model was then used for a pilot chemical screen to target specific aspects of this switch. Increased activity of p38? and ? Mitogen Activated Protein Kinases (MAPKs) were identified as a necessary signal regulating expression of MnSOD, and heme oxygenase 1 (HO-1), with consequent changes in ROS-mediated injury. Additionally, multiplex cytokine profiling detected p38 MAPK-dependent secretion of IL-6, MCP-1, and MIP-2?, which are proinflammatory signals recently implicated in damage to the inner retina. These data provide a mechanism to link increased oxidative stress to proinflammatory signaling by astrocytes, and establish this assay as a useful model to further dissect factors regulating the reactive switch. PMID:24376630

Nahirnyj, Adrian; Livne-Bar, Izhar; Guo, Xiaoxin; Sivak, Jeremy M.

2013-01-01

206

Arctigenin, a dietary phytoestrogen, induces apoptosis of estrogen receptor-negative breast cancer cells through the ROS/p38 MAPK pathway and epigenetic regulation.  

Science.gov (United States)

This study investigates the anticancer effect of arctigenin (ATG), a natural lignan product of Arctium lappa L., in human breast cancer MDA-MB-231 cells. Results indicate that ATG inhibits MDA-MB-231 cell growth by inducing apoptosis in vitro and in vivo. ATG triggers the mitochondrial caspase-independent pathways, as indicated by changes in Bax/Bcl-2 ratio, resulting in AIF and EndoG nuclear translocation. ATG increased cellular reactive oxygen species (ROS) production by increasing p22(phox)/NADPH oxidase 1 interaction and decreasing glutathione level. ATG clearly increases the activation of p38 MAPK, but not JNK and ERK1/2. Antioxidant EUK-8, a synthetic catalytic superoxide and hydrogen peroxide scavenger, significantly decreases ATG-mediated p38 activation and apoptosis. Blocking p38 with a specific inhibitor suppresses ATG-mediated Bcl-2 downregulation and apoptosis. Moreover, ATG activates ATF-2, a transcription factor activated by p38, and then upregulates histone H3K9 trimethylation in the Bcl-2 gene promoter region, resulting in Bcl-2 downregulation. Taken together, the results demonstrate that ATG induces apoptosis of MDA-MB-231 cells via the ROS/p38 MAPK pathway and epigenetic regulation of Bcl-2 by upregulation of histone H3K9 trimethylation. PMID:24140706

Hsieh, Chia-Jung; Kuo, Po-Lin; Hsu, Ying-Chan; Huang, Ya-Fang; Tsai, Eing-Mei; Hsu, Ya-Ling

2014-02-01

207

Neferine from Nelumbo nucifera induces autophagy through the inhibition of PI3K/Akt/mTOR pathway and ROS hyper generation in A549 cells.  

Science.gov (United States)

Previously we have reported that neferine from the medicinal plant Nelumbo nucifera, inhibited cancer cell proliferation by inducing apoptosis. The present study was focused on the action mechanism of neferine in inducing autophagy in lung cancer cells. Neferine markedly inhibited A549 cell proliferation in a dose dependent manner. Acidic vesicular accumulation was observed in neferine treated cells as an indication of autophagy. Neferine could induce the conversion of LC3B-I to LC3B-II without affecting the expression levels of PI3KCIII and Beclin1. It has been observed that neferine mediated autophagy is dependent on inhibition of PI3K/Akt/mTOR signaling by neferine. Neferine treatment could also lead to the ROS hypergeneration and depletion of cellular antioxidant, GSH. The results demonstrate that neferine-induced autophagy is mediated through ROS hypergeneration and mTOR inhibition. Taken together, the present study unveils a novel mechanism of action of neferine on lung cancer cells in the induction of autophagy. PMID:23993526

Poornima, Paramasivan; Weng, Ching Feng; Padma, Viswanadha Vijaya

2013-12-15

208

Activation of volume-sensitive outwardly rectifying chloride channel by ROS contributes to ER stress and cardiac contractile dysfunction: involvement of CHOP through Wnt.  

Science.gov (United States)

Endoplasmic reticulum (ER) stress occurring in stringent conditions is critically involved in cardiomyocytes apoptosis and cardiac contractile dysfunction (CCD). However, the molecular machinery that mediates cardiac ER stress and subsequent cell death remains to be fully deciphered, which will hopefully provide novel therapeutic targets for these disorders. Here, we establish tunicamycin-induced model of cardiomyocyte ER stress, which effectively mimicks pathological stimuli to trigger CCD. Tunicamycin activates volume-sensitive outward rectifying Cl(-) currents. Blockade of the volume-sensitive outwardly rectifying (VSOR) Cl(-) channel by 4,4'-diisothiocya-natostilbene-2,2'-disulfonic acid (DIDS), a non-selective Cl(-) channel blocker, and 4-(2-butyl-6,7-dichlor-2-cyclopentyl-indan-1-on-5-yl) oxybutyric acid (DCPIB), a selective VSOR Cl(-) channel blocker, improves cardiac contractility, which correlates with suppressed ER stress through inhibiting the canonical GRP78/eIF2?/ATF4 and XBP1 pathways, and promotes survival of cardiomyocytes by inverting tunicamycin-induced decrease of Wnt through the CHOP pathway. VSOR activation of tunicamycin-treated cardiomyocytes is attributed to increased intracellular levels of reactive oxygen species (ROS). Our study demonstrates a pivotal role of ROS/VSOR in mediating ER stress and functional impairment of cardiomyocytes via the CHOP-Wnt pathway, and suggests the therapeutic values of VSOR Cl(-) channel blockers against ER stress-associated cardiac anomalies. PMID:25412307

Shen, M; Wang, L; Wang, B; Wang, T; Yang, G; Shen, L; Wang, T; Guo, X; Liu, Y; Xia, Y; Jia, L; Wang, X

2014-01-01

209

Generation of reactive oxygen species mediated by humic-like substances in atmospheric aerosols.  

Science.gov (United States)

Particulate matter (PM)-mediated reactive oxygen species (ROS) generation has been implicated in health effects posed by PM. Humic-like substances (HULIS) are an unresolved mixture of water-extracted organic compounds from atmospheric aerosol particles or isolated from fog/cloudwater samples. In this study, we use a cell-free dithiothreitol (DTT) assay to measure ROS production mediated by HULIS. The HULIS samples are isolated from aerosols collected at a rural location and a suburban location in the Pearl River Delta, China. In our experiments, ROS activities by residue metal ions in the HULIS fraction are suppressed by including a strong chelating agent in the DTT assay. Under conditions of DTT consumption not exceeding 90%, the HULIS-catalyzed oxidation of DTT follows the zero-order kinetics with respect to DTT concentration, and the rate of DTT oxidation is proportional to the dose of HULIS. The ROS activity of the aerosol HULIS, on a per unit mass basis is 2% of the ROS activity by a reference quinone compound, 1,4-naphthoquinone and exceeds that of two aquatic fulvic acids. The HULIS fraction in the ambient samples tested exhibits comparable ROS activities to the organic solvent extractable fraction, which would contain compounds such as quinones, a known organic compound class capable of catalyzing generation of ROS in cells. HULIS was found to be the major redox active constituent of the water-extractable organic fraction in PM. It is plausible that HULIS contains reversible redox sites, thereby serving as electron carriers to catalyze the formation of ROS. Our work suggests that HULIS could be an active PM component in generating ROS and further work is warranted to characterize its redox properties. PMID:22044074

Lin, Peng; Yu, Jian Zhen

2011-12-15

210

Arsenic trioxide induces human pulmonary fibroblast cell death via increasing ROS levels and GSH depletion.  

Science.gov (United States)

Arsenic trioxide (ATO; As2O3) induces apoptotic cell death in various cancer cells including lung cancer via the induction of reactive oxygen species (ROS). However, little is known about the toxicological effects of ATO on normal primary lung cells. Here, we investigated the effects of N-acetyl cysteine (NAC) and vitamin C (well-known antioxidants) or L-buthionine sulfoximine (BSO; an inhibitor of GSH synthesis) on ATO-treated human pulmonary fibroblast (HPF) cells in relation to cell death, ROS and glutathione (GSH). ATO induced growth inhibition and death in HPF cells, accompanied by the loss of mitochondrial membrane potential (MMP; ??m). ATO increased ROS levels including O2•- and GSH depleted cell numbers. NAC attenuated the growth inhibition, death and MMP (??m) loss in ATO-treated HPF cells and also decreased the ROS levels in these cells. However, vitamin C enhanced the growth inhibition, death, MMP (??m) loss and GSH depletion by ATO and even strongly increased mitochondrial O2•- levels in ATO-treated HPF cells. BSO showed a strong increase in ROS levels in ATO-treated HPF cells and intensified the growth inhibition, cell death, MMP (??m) loss and GSH depletion. Moreover, superoxide dismutase (SOD2) or thioredoxin (TXN) siRNAs attenuated HPF cell death by ATO, which was not correlated with ROS and GSH level changes. In conclusion, ATO induced the growth inhibition and death of HPF cells, accompanied by increasing ROS levels and GSH depletion. NAC attenuated HPF cell death by ATO whereas vitamin C and BSO enhanced the death. PMID:22684917

You, Bo Ra; Park, Woo Hyun

2012-08-01

211

ROS and endothelial nitric oxide synthase (eNOS)-dependent trafficking of angiotensin II type 2 receptor begets neuronal NOS in cardiac myocytes.  

Science.gov (United States)

Angiotensin II (Ang II), a potent precursor of hypertrophy and heart failure, upregulates neuronal nitric oxide synthase (nNOS or NOS1) in the myocardium. Here, we investigate the involvement of type 1 and 2 angiotensin receptors (AT1R and AT2R) and molecular mechanisms mediating Ang II-upregulation of nNOS. Our results showed that pre-treatment of left ventricular (LV) myocytes with antagonists of AT1R or AT2R (losartan, PD123319) and ROS scavengers (apocynin, tiron or PEG-catalase) blocked Ang II-upregulation of nNOS. Surface biotinylation or immunocytochemistry experiments demonstrated that AT1R expression in plasma membrane was progressively decreased (internalization), whereas AT2R was increased (membrane trafficking) by Ang II. Inhibition of AT1R or ROS scavengers prevented Ang II-induced translocation of AT2R to plasma membrane, suggesting an alignment of AT1R-ROS-AT2R. Furthermore, Ang II increased eNOS-Ser(1177) but decreased eNOS-Thr(495), indicating concomitant activation of eNOS. Intriguingly, ROS scavengers but not AT2R antagonist prevented Ang II-activation of eNOS. NOS inhibitor (L-NG-Nitroarginine Methyl Ester, L-NAME) or eNOS gene deletion (eNOS(-/-)) abolished Ang II-induced membrane trafficking of AT2R, nNOS protein expression and activity. Mechanistically, S-nitrosation of AT2R was increased by sodium nitroprusside (SNP), a NO donor. Site-specific mutagenesis analysis reveals that C-terminal cysteine 349 in AT2R is essential in AT2R translocation to plasma membrane. Taken together, we demonstrate, for the first time, that Ang II upregulates nNOS protein expression and activity via AT1R/ROS/eNOS-dependent S-nitrosation and membrane translocation of AT2R. Our results suggest a novel crosstalk between AT1R and AT2R in regulating nNOS via eNOS in the myocardium under pathogenic stimuli. PMID:25804308

Jang, Ji Hyun; Chun, Jung Nyeo; Godo, Shigeo; Wu, Guangyu; Shimokawa, Hiroaki; Jin, Chun Zi; Jeon, Ju Hong; Kim, Sung Joon; Jin, Zhe Hu; Zhang, Yin Hua

2015-05-01

212

Iron-sulfur protein in mitochondrial complexes of Spodoptera litura as potential site for ROS generation.  

Science.gov (United States)

Mitochondrial complex I is the main source of reactive oxygen species (ROS) production, but the exact site of superoxide generation or their relative contribution is not clear. This study aims to determine the function of iron-sulfur clusters (ISCU) in the initiation of ROS generation. ISCU2 and ISCU8 were cloned from Spodoptera litura which shared the conserved amino acid sequence with other insects. The expressions of the two genes were ubiquitous throughout the whole development stages and tissues. Knockdown of ISCU2 and ISCU8 resulted in the decline of the ROS, whereas rotenone and azadirachtin treatment up-regulated ROS levels by increasing mRNA expression. Furthermore, antioxidant enzyme activity of SOD and POD were up-regulated by rotenone and azadirachtin treatment and then declined after ISCU was silenced. Our results suggest the possibility that the molecules of ISCU2 and ISCU8 in complex I may serve as potential sites in the initiation of ROS generation. PMID:25257538

Li, Liangde; Dong, Xiaolin; Shu, Benshui; Wang, Zheng; Hu, Qiongbo; Zhong, Guohua

2014-12-01

213

Intercultural Mediation  

OpenAIRE

The Intercultural Mediator facilitates exchanges between people of different socio-cultural backgrounds and acts as a bridge between immigrants and national and local associations, health organizations, services and offices in order to foster integration of every single individual. As the use mediation increases, mediators are more likely to be involved in cross-cultural mediation, but only the best mediators have the opportunity to mediate cross border business disputes or international poli...

Dragos Marian Radulescu; Denisa Mitrut

2012-01-01

214

Elucidating hormonal/ROS networks during seed germination: insights and perspectives  

DEFF Research Database (Denmark)

While authors have traditionally emphasized the deleterious effects of reactive oxygen species (ROS) on seed biology, their role as signaling molecules during seed dormancy alleviation and germination is now the focus of many studies around the world. Over the last few years, studies using “-omics” technologies together with physiological and biochemical approaches have revealed that seed germination is a very complex process that depends on multiple biochemical and molecular variables. The pivotal role of phytohormones in promoting germination now appears to be interdependent with ROS metabolism, involving mitogen-activated protein kinase cascade activation, gene expression and post-translational protein modifications. This review is, thus, an attempt to summarize the new discoveries involving ROS and seed germination. The study of these interactions may supply markers of seed quality that might eventually be used in breeding programs to improve crop yields.

Diaz-Vivancos, Pedro; Barba Espin, Gregorio

2013-01-01

215

The Roles of ROS and ABA in Systemic Acquired Acclimation[OPEN  

Science.gov (United States)

Systemic responses to environmental stimuli are essential for the survival of multicellular organisms. In plants, they are initiated in response to many different signals including pathogens, wounding, and abiotic stresses. Recent studies highlighted the importance of systemic acquired acclimation to abiotic stresses in plants and identified several different signals involved in this response. These included reactive oxygen species (ROS) and calcium waves, hydraulic waves, electric signals, and abscisic acid (ABA). Here, we address the interactions between ROS and ABA at the local and systemic tissues of plants subjected to abiotic stress and attempt to propose a model for the involvement of ROS, ABA, and stomata in systemic signaling leading to systemic acquired acclimation. PMID:25604442

Mittler, Ron; Blumwald, Eduardo

2015-01-01

216

Hyperoxygenation attenuated a murine model of atopic dermatitis through raising skin level of ROS.  

Science.gov (United States)

Atopic dermatitis (AD) is a chronic inflammatory skin disease resulting from excessive stimulation of immune cells. Traditionally, reactive oxygen species (ROS) have been implicated in the progression of inflammatory diseases, but several opposing observations suggest the protective role of ROS in inflammatory disease. Recently, we demonstrated ROS prevented imiquimod-induced psoriatic dermatitis through enhancing regulatory T cell function. Thus, we hypothesized AD might also be attenuated in elevated levels of ROS through tissue hyperoxygenation, such as by hyperbaric oxygen therapy (HBOT) or applying an oxygen-carrying chemical, perfluorodecalin (PFD). Elevated levels of ROS in the skin have been demonstrated directly by staining with dihydroethidum as well as indirectly by immunohistochemistry (IHC) for indoleamine 2,3-dioxygenase (IDO). A murine model of AD was developed by repeated application of a chemical irritant (1% 2,4-dinitrochlorobenzene) and house dust mite (Dermatophagoide farinae) extract on one ear of BALB/c mice. The results showed treatment with HBOT or PFD significantly attenuated AD, comparably with 0.1% prednicarbate without any signs of side effects, such as telangiectasia. The expressions of interleukin-17A and interferon-? were also decreased in the AD lesions by treatment with HBOT or PFD. Enhanced expression of IDO and reduced level of hypoxia-inducible factor-1?, in association with increased frequency of FoxP3+ regulatory T cells in the AD lesions, might be involved in the underlying mechanism of oxygen therapy. Taken together, it was suggested that tissue hyperoxygenation, by HBOT or treatment with PFD, might attenuate AD through enhancing skin ROS level. PMID:25275529

Kim, Hyung-Ran; Kim, Jung-Hwan; Choi, Eun-Jeong; Lee, Yeo Kyong; Kie, Jeong-Hae; Jang, Myoung Ho; Seoh, Ju-Young

2014-01-01

217

Primary fibroblasts of NDUFS4(-/-) mice display increased ROS levels and aberrant mitochondrial morphology.  

Science.gov (United States)

The human NDUFS4 gene encodes an accessory subunit of the first mitochondrial oxidative phosphorylation complex (CI) and, when mutated, is associated with progressive neurological disorders. Here we analyzed primary muscle and skin fibroblasts from NDUFS4(-/-) mice with respect to reactive oxygen species (ROS) levels and mitochondrial morphology. NDUFS4(-/-) fibroblasts displayed an inactive CI subcomplex on native gels but proliferated normally and showed no obvious signs of apoptosis. Oxidation of the ROS sensor hydroethidium was increased and mitochondria were less branched and/or shorter in NDUFS4(-/-) fibroblasts. We discuss the relevance of these findings with respect to previous results and therapy development. PMID:23234723

Valsecchi, Federica; Grefte, Sander; Roestenberg, Peggy; Joosten-Wagenaars, Jori; Smeitink, Jan A M; Willems, Peter H G M; Koopman, Werner J H

2013-09-01

218

As a novel p53 direct target, bidirectional gene HspB2/?B-crystallin regulates the ROS level and Warburg effect.  

Science.gov (United States)

Many mammalian genes are composed of bidirectional gene pairs with the two genes separated by less than 1.0kb. The transcriptional regulation and function of these bidirectional genes remain largely unclear. Here, we report that bidirectional gene pair HspB2/?B-crystallin, both of which are members of the small heat shock protein gene family, is a novel direct target gene of p53. Two potential binding sites of p53 are present in the intergenic region of HspB2/?B-crystallin. p53 up-regulated the bidirectional promoter activities of HspB2/?B-crystallin. Actinomycin D (ActD), an activator of p53, induces the promoter and protein activities of HspB2/?B-crystallin. p53 binds to two p53 binding sites in the intergenic region of HspB2/?B-crystallin in vitro and in vivo. Moreover, the products of bidirectional gene pair HspB2/?B-crystallin regulate glucose metabolism, intracellular reactive oxygen species (ROS) level and the Warburg effect by affecting metabolic genes, including the synthesis of cytochrome c oxidase 2 (SCO2), hexokinase II (HK2), and TP53-induced glycolysis and apoptosis regulator (TIGAR). The ROS level and the Warburg effect are affected after the depletion of p53, HspB2 and ?B-crystallin respectively. Finally, we show that both HspB2 and ?B-crystallin are linked with human renal carcinogenesis. These findings provide novel insights into the role of p53 as a regulator of bidirectional gene pair HspB2/?B-crystallin-mediated ROS and the Warburg effect. PMID:24859470

Liu, Shuang; Yan, Bin; Lai, Weiwei; Chen, Ling; Xiao, Desheng; Xi, Sichuan; Jiang, Yiqun; Dong, Xin; An, Jing; Chen, Xiang; Cao, Ya; Tao, Yongguang

2014-07-01

219

Attenuation of Proinflammatory Responses by S-[6]-Gingerol via Inhibition of ROS/NF-Kappa B/COX2 Activation in HuH7 Cells.  

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Introduction. Hepatic inflammation underlies the pathogenesis of chronic diseases such as insulin resistance and type 2 diabetes mellitus. S-[6]-Gingerol has been shown to have anti-inflammatory properties. Important inflammatory mediators of interleukins include nuclear factor ? B (NF ? B) and cyclooxygenase 2 (COX2). We now explore the mechanism of anti-inflammatory effects of S-[6]-gingerol in liver cells. Methods. HuH7 cells were stimulated with IL1? to establish an in vitro hepatic inflammatory model. Results. S-[6]-Gingerol attenuated IL1?-induced inflammation and oxidative stress in HuH7 cells, as evidenced by decreasing mRNA levels of inflammatory factor IL6, IL8, and SAA1, suppression of ROS generation, and increasing mRNA levels of DHCR24. In addition, S-[6]-gingerol reduced IL1?-induced COX2 upregulation as well as NF ? B activity. Similar to the protective effects of S-[6]-gingerol, both NS-398 (a selective COX2 inhibitor) and PDTC (a selective NF ? B inhibitor) suppressed mRNA levels of IL6, IL8, and SAA1. Importantly, PDTC attenuated IL1?-induced overexpression of COX2. Of particular note, the protective effect of S-[6]-gingerol against the IL1?-induced inflammatory response was similar to that of BHT, an ROS scavenger. Conclusions. The findings of this study demonstrate that S-[6]-gingerol protects HuH7 cells against IL1?-induced inflammatory insults through inhibition of the ROS/NF ? B/COX2 pathway. PMID:23843863

Li, Xiao-Hong; McGrath, Kristine C Y; Tran, Van H; Li, Yi-Ming; Duke, Colin C; Roufogalis, Basil D; Heather, Alison K

2013-01-01

220

Intercultural Mediation  

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Full Text Available The Intercultural Mediator facilitates exchanges between people of different socio-cultural backgrounds and acts as a bridge between immigrants and national and local associations, health organizations, services and offices in order to foster integration of every single individual. As the use mediation increases, mediators are more likely to be involved in cross-cultural mediation, but only the best mediators have the opportunity to mediate cross border business disputes or international politics conflicts. This article attempts to provide a new perspective about the intercultural mediation.

Dragos Marian Radulescu

2012-11-01

221

Abrus precatorius agglutinin-derived peptides induce ROS-dependent mitochondrial apoptosis through JNK and Akt/P38/P53 pathways in HeLa cells.  

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10kDAGP, a tryptic digest of Abrus precatorius lectin 'Agglutinin' is known to induce apoptosis by mitochondria-dependent pathways in human cervical cancer (HeLa) cells. The present study was focused on deciphering the detailed molecular mechanism of apoptosis induction in vitro by 10kDAGP and also its in vivo therapeutic efficacy. For in vivo model, HeLa cell encapsulated hollow fiber was implanted in Swiss Albino mice and treated with 10kDAGP. Our results showed that 10kDAGP was able to enter the cell within a span of 20min and co-localized with mitochondria after 90min. of incubation. A drastic loss of mitochondrial membrane potential was noted within 6h of 10kDAGP administration along with an increase in ROS generation. ROS further led to symptoms of early apoptosis by deregulating Akt (Protein Kinase B) and activating c-Jun N-terminal Kinase (JNK), p38 Mitogen Activated Protein Kinase (MAPK), p53, and autophagy starting from ?8h of incubation. Besides in vitro conditions, 10kDAGP activated JNK to mediate cancer cell killing in vivo. Therefore, 10kDAGP can be an excellent therapeutic agent as it can act through different ways in the cellular system. Future studies are directed to screen out active peptides from the pool of peptides and to study whether the mode of action is in synergistic way or in individual forms. PMID:25305377

Behera, Birendra; Mishra, Debasish; Roy, Bibhas; Devi, K Sanjana P; Narayan, Rajan; Das, Joyjyoti; Ghosh, Sudip K; Maiti, Tapas K

2014-10-01

222

Icariside II inhibits cell proliferation and induces cell cycle arrest through the ROS-p38-p53 signaling pathway in A375 human melanoma cells.  

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Icariside II (IS) is a metabolite of icariin, which is derived from Herba Epimedii. In the present study, the antiproliferative effects of IS on A375 human melanoma cells were examined in vitro and a possible mechanism through the ROS-p38-p53 pathway is discussed. A cell WST-8 assay revealed that treatment with IS markedly reduced cell viability from 77 to 21% (25 and 100 µM, respectively), and cell counting demonstrated that IS treatment reduced cell proliferation. IS treatment also induced cell cycle arrest of A375 cells at the G0/G1 and G2/M transitions and inhibited the expression of cell-cycle related proteins, including cyclin E, cyclin-dependent kinase 2 (CDK2), cyclin B1 and phosphorylated cyclin-dependent kinase 1 (P-CDK1). In this study, it was determined that IS inhibits cell proliferation and induces cell cycle arrest through the generation of reactive oxygen species and activation of p38 and p53. These findings were further supported by the evidence that pretreatment with N-acetyl-L-cysteine, SB203580 or pifithrin-? significantly blocked IS-induced reduction of cell viability, increase of cell death and cell cycle arrest. In conclusion, IS inhibits cell proliferation and induces cell cycle arrest. Crucially, it was confirmed that these effects were mediated at least in part by activating the ROS-p38-p53 pathway. PMID:25333296

Wu, Jinfeng; Song, Tao; Liu, Shuyong; Li, Xiaomei; Li, Gang; Xu, Jinhua

2015-01-01

223

Jadomycin breast cancer cytotoxicity is mediated by a copper-dependent, reactive oxygen species-inducing mechanism.  

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Jadomycins are natural products biosynthesized by the bacteria Streptomyces venezuelae which kill drug-sensitive and multidrug-resistant breast cancer cells in culture. Currently, the mechanisms of jadomycin cytotoxicity are poorly understood; however, reactive oxygen species (ROS)-induced DNA cleavage is suggested based on bacterial plasmid DNA cleavage studies. The objective of this study was to determine if and how ROS contribute to jadomycin cytotoxicity in drug-sensitive MCF7 (MCF7-CON) and taxol-resistant MCF7 (MCF7-TXL) breast cancer cells. As determined using an intracellular, fluorescent, ROS-detecting probe, jadomycins B, S, SPhG, and F dose dependently increased intracellular ROS activity 2.5- to 5.9-fold. Cotreatment with the antioxidant N-acetyl cysteine lowered ROS concentrations to below baseline levels and decreased the corresponding cytotoxic potency of the four jadomycins 1.9- to 3.3-fold, confirming a ROS-mediated mechanism. Addition of CuSO4 enhanced, whereas addition of the Cu(II)-chelator d-penicillamine reduced, the ROS generation and cytotoxicity of each jadomycin. Specific inhibitors of the antioxidant enzymes, superoxide dismutase 1, glutathione S-transferase, and thioredoxin reductase, but not catalase, enhanced jadomycin-mediated ROS generation and anticancer activity. In conclusion, the results indicate that jadomycin cytotoxicity involves the generation of cytosolic superoxide via a Cu(II)-jadomycin reaction, a mechanism common to all jadomycins tested and observed in MCF7-CON and drug-resistant MCF7-TXL cells. The superoxide dismutase 1, glutathione, and peroxiredoxin/thioredoxin cellular antioxidant enzyme pathways scavenged intracellular ROS generated by jadomycin treatment. Blocking these antioxidant pathways could serve as a strategy to enhance jadomycin cytotoxic potency in drug-sensitive and multidrug-resistant breast cancers. PMID:25729577

Hall, Steven R; Blundon, Heather L; Ladda, Matthew A; Robertson, Andrew W; Martinez-Farina, Camilo F; Jakeman, David L; Goralski, Kerry B

2015-03-01

224

Jadomycin breast cancer cytotoxicity is mediated by a copper-dependent, reactive oxygen species–inducing mechanism  

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Jadomycins are natural products biosynthesized by the bacteria Streptomyces venezuelae which kill drug-sensitive and multidrug-resistant breast cancer cells in culture. Currently, the mechanisms of jadomycin cytotoxicity are poorly understood; however, reactive oxygen species (ROS)–induced DNA cleavage is suggested based on bacterial plasmid DNA cleavage studies. The objective of this study was to determine if and how ROS contribute to jadomycin cytotoxicity in drug-sensitive MCF7 (MCF7-CON) and taxol-resistant MCF7 (MCF7-TXL) breast cancer cells. As determined using an intracellular, fluorescent, ROS-detecting probe, jadomycins B, S, SPhG, and F dose dependently increased intracellular ROS activity 2.5- to 5.9-fold. Cotreatment with the antioxidant N-acetyl cysteine lowered ROS concentrations to below baseline levels and decreased the corresponding cytotoxic potency of the four jadomycins 1.9- to 3.3-fold, confirming a ROS-mediated mechanism. Addition of CuSO4 enhanced, whereas addition of the Cu(II)-chelator d-penicillamine reduced, the ROS generation and cytotoxicity of each jadomycin. Specific inhibitors of the antioxidant enzymes, superoxide dismutase 1, glutathione S-transferase, and thioredoxin reductase, but not catalase, enhanced jadomycin-mediated ROS generation and anticancer activity. In conclusion, the results indicate that jadomycin cytotoxicity involves the generation of cytosolic superoxide via a Cu(II)-jadomycin reaction, a mechanism common to all jadomycins tested and observed in MCF7-CON and drug-resistant MCF7-TXL cells. The superoxide dismutase 1, glutathione, and peroxiredoxin/thioredoxin cellular antioxidant enzyme pathways scavenged intracellular ROS generated by jadomycin treatment. Blocking these antioxidant pathways could serve as a strategy to enhance jadomycin cytotoxic potency in drug-sensitive and multidrug-resistant breast cancers. PMID:25729577

Hall, Steven R; Blundon, Heather L; Ladda, Matthew A; Robertson, Andrew W; Martinez-Farina, Camilo F; Jakeman, David L; Goralski, Kerry B

2015-01-01

225

Arabidopsis GRI is involved in the regulation of cell death induced by extracellular ROS.  

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Reactive oxygen species (ROS) have important functions in plant stress responses and development. In plants, ozone and pathogen infection induce an extracellular oxidative burst that is involved in the regulation of cell death. However, very little is known about how plants can perceive ROS and regulate the initiation and the containment of cell death. We have identified an Arabidopsis thaliana protein, GRIM REAPER (GRI), that is involved in the regulation of cell death induced by extracellular ROS. Plants with an insertion in GRI display an ozone-sensitive phenotype. GRI is an Arabidopsis ortholog of the tobacco flower-specific Stig1 gene. The GRI protein appears to be processed in leaves with a release of an N-terminal fragment of the protein. Infiltration of the N-terminal fragment of the GRI protein into leaves caused cell death in a superoxide- and salicylic acid-dependent manner. Analysis of the extracellular GRI protein yields information on how plants can initiate ROS-induced cell death during stress response and development. PMID:19279211

Wrzaczek, Michael; Brosché, Mikael; Kollist, Hannes; Kangasjärvi, Jaakko

2009-03-31

226

Photocatalytic ROS production and phototoxicity of titanium dioxide nanoparticles is dependent on solar UV radiation spectrum  

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Generation of reactive oxygen species (ROS) by titanium dioxide nanoparticles (nano-TiO2) and its consequent phototoxicity to Daphnia magna were measured under different solar UV radiation spectrum by applying a series of optical filters in a solar simulator. Removing UVB (280-32...

227

Alterations of ROS pathways in scleroderma begin at stem cell level.  

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Scleroderma is a chronic systemic autoimmune disease (primarily of the skin) characterized by fibrosis (or hardening), vascular alterations and autoantibodies production.There are currently no effective therapies against this devastating and often lethal disorder. Despite the interest for the immunomodulatory effects of mesenchymal stem cells (MSCs) in autoimmune diseases, the role of MSCs in scleroderma is still unknown. A pivotal role in scleroderma onset is played by oxidative stress associated with the accumulation of great amounts of reactive oxygen species (ROS). This study depicts some phenotypic and functional features of MSCs isolated from the skin of healthy and scleroderma patients; the ROS production and accumulation, the expression of ERK1/2 and the effects of the stimulation with PDGF, were analyzed in MSCs; results were compared to those observed in primary fibroblasts (Fbs) isolated from the same subjects. We found that the pro-oxidant environment exerted by scleroderma affects MSCs, which are still able to counteract the ROS accumulation by improving the antioxidant defenses. On the contrary, scleroderma fibroblasts show a disruption of these mechanisms, with consequent ROS increase and the activation of the cascade triggered by scleroderma auto-antibodies against PDGFR. PMID:23489700

Orciani, M; Svegliati, S; Gorbi, S; Spadoni, T; Lazzarini, R; Regoli, F; Di Primio, R; Gabrielli, A

2013-01-01

228

ROS production and protein oxidation as a novel mechanism for seed dormancy alleviation.  

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At harvest, sunflower (Helianthus annuus L.) seeds are dormant and unable to germinate at temperatures below 15 degrees C. Seed storage in the dry state, known as after-ripening, is associated with an alleviation of embryonic dormancy allowing subsequent germination at suboptimal temperatures. To identify the process by which dormancy is broken during after-ripening, we focused on the role of reactive oxygen species (ROS) in this phenomenon. After-ripening entailed a progressive accumulation of ROS, namely superoxide anions and hydrogen peroxide, in cells of embryonic axes. This accumulation, which was investigated at the cellular level by electron microscopy, occurred concomitantly with lipid peroxidation and oxidation (carbonylation) of specific embryo proteins. Incubation of dormant seeds for 3 h in the presence of hydrogen cyanide (a compound that breaks dormancy) or methylviologen (a ROS-generating compound) also released dormancy and caused the oxidation of a specific set of embryo proteins. From these observations, we propose a novel mechanism for seed dormancy alleviation. This mechanism involves ROS production and targeted changes in protein carbonylation patterns. PMID:17376157

Oracz, Krystyna; El-Maarouf Bouteau, Hayat; Farrant, Jill M; Cooper, Keren; Belghazi, Maya; Job, Claudette; Job, Dominique; Corbineau, Françoise; Bailly, Christophe

2007-05-01

229

Superparamagnetic iron oxide nanoparticles: amplifying ROS stress to improve anticancer drug efficacy.  

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Superparamagnetic iron oxide nanoparticles (SPION) are an important and versatile nano- platform with broad biological applications. Despite extensive studies, the biological and pharmacological activities of SPION have not been exploited in therapeutic applications. Recently, ?-lapachone (?-lap), a novel anticancer drug, has shown considerable cancer specificity by selectively increasing reactive oxygen species (ROS) stress in cancer cells. In this study, we report that pH-responsive SPION-micelles can synergize with ?-lap for improved cancer therapy. These SPION-micelles selectively release iron ions inside cancer cells, which interact with hydrogen peroxide (H(2)O(2)) generated from ?-lap in a tumor-specific, NQO1-dependent manner. Through Fenton reactions, these iron ions escalate the ROS stress in ?-lap-exposed cancer cells, thereby greatly enhancing the therapeutic index of ?-lap. More specifically, a 10-fold increase in ROS stress was detected in ?-lap-exposed cells pretreated with SPION-micelles over those treated with ?-lap alone, which also correlates with significantly increased cell death. Catalase treatment of cells or administration of an iron chelator can block the therapeutic synergy. Our data suggest that incorporation of SPION-micelles with ROS-generating drugs can potentially improve drug efficacy during cancer treatment, thereby provides a synergistic strategy to integrate imaging and therapeutic functions in the development of theranostic nanomedicine. PMID:23423156

Huang, Gang; Chen, Huabing; Dong, Ying; Luo, Xiuquan; Yu, Haijun; Moore, Zachary; Bey, Erik A; Boothman, David A; Gao, Jinming

2013-01-01

230

ROS and redox signalling in the response of plants to abiotic stress.  

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The redox state of the chloroplast and mitochondria, the two main powerhouses of photosynthesizing eukaryotes, is maintained by a delicate balance between energy production and consumption, and affected by the need to avoid increased production of reactive oxygen species (ROS). These demands are especially critical during exposure to extreme environmental conditions, such as high light (HL) intensity, heat, drought or a combination of different environmental stresses. Under these conditions, ROS and redox cues, generated in the chloroplast and mitochondria, are essential for maintaining normal energy and metabolic fluxes, optimizing different cell functions, activating acclimation responses through retrograde signalling, and controlling whole-plant systemic signalling pathways. Regulation of the multiple redox and ROS signals in plants requires a high degree of coordination and balance between signalling and metabolic pathways in different cellular compartments. In this review, we provide an update on ROS and redox signalling in the context of abiotic stress responses, while addressing their role in retrograde regulation, systemic acquired acclimation and cellular coordination in plants. PMID:21486305

Suzuki, Nobuhiro; Koussevitzky, Shai; Mittler, Ron; Miller, Gad

2012-02-01

231

Cellular localization of ROS and NO in olive reproductive tissues during flower development  

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Full Text Available Abstract Background Recent studies have shown that reactive oxygen species (ROS and nitric oxide (NO are involved in the signalling processes taking place during the interactions pollen-pistil in several plants. The olive tree (Olea europaea L. is an important crop in Mediterranean countries. It is a dicotyledonous species, with a certain level of self-incompatibility, fertilisation preferentially allogamous, and with an incompatibility system of the gametophytic type not well determined yet. The purpose of the present study was to determine whether relevant ROS and NO are present in the stigmatic surface and other reproductive tissues in the olive over different key developmental stages of the reproductive process. This is a first approach to find out the putative function of these signalling molecules in the regulation of the interaction pollen-stigma. Results The presence of ROS and NO was analyzed in the olive floral organs throughout five developmental stages by using histochemical analysis at light microscopy, as well as different fluorochromes, ROS and NO scavengers and a NO donor by confocal laser scanning microscopy. The "green bud" stage and the period including the end of the "recently opened flower" and the "dehiscent anther" stages displayed higher concentrations of the mentioned chemical species. The stigmatic surface (particularly the papillae and the stigma exudate, the anther tissues and the pollen grains and pollen tubes were the tissues accumulating most ROS and NO. The mature pollen grains emitted NO through the apertural regions and the pollen tubes. In contrast, none of these species were detected in the style or the ovary. Conclusion The results obtained clearly demonstrate that both ROS and NO are produced in the olive reproductive organs in a stage- and tissue- specific manner. The biological significance of the presence of these products may differ between early flowering stages (defence functions and stages where there is an intense interaction between pollen and pistil which may determine the presence of a receptive phase in the stigma. The study confirms the enhanced production of NO by pollen grains and tubes during the receptive phase, and the decrease in the presence of ROS when NO is actively produced.

Alché Juan

2010-02-01

232

Seizure activity results in calcium- and mitochondria-independent ROS production via NADPH and xanthine oxidase activation.  

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Seizure activity has been proposed to result in the generation of reactive oxygen species (ROS), which then contribute to seizure-induced neuronal damage and eventually cell death. Although the mechanisms of seizure-induced ROS generation are unclear, mitochondria and cellular calcium overload have been proposed to have a crucial role. We aim to determine the sources of seizure-induced ROS and their contribution to seizure-induced cell death. Using live cell imaging techniques in glioneuronal cultures, we show that prolonged seizure-like activity increases ROS production in an NMDA receptor-dependent manner. Unexpectedly, however, mitochondria did not contribute to ROS production during seizure-like activity. ROS were generated primarily by NADPH oxidase and later by xanthine oxidase (XO) activity in a calcium-independent manner. This calcium-independent neuronal ROS production was accompanied by an increase in intracellular [Na(+)] through NMDA receptor activation. Inhibition of NADPH or XO markedly reduced seizure-like activity-induced neuronal apoptosis. These findings demonstrate a critical role for ROS in seizure-induced neuronal cell death and identify novel therapeutic targets. PMID:25275601

Kovac, S; Domijan, A-M; Walker, M C; Abramov, A Y

2014-01-01

233

NOX4 activity is determined by mRNA levels and reveals a unique pattern of ROS generation  

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NOX4 is an enigmatic member of the NOX (NADPH oxidase) family of ROS (reactive oxygen species)-generating NADPH oxidases. NOX4 has a wide tissue distribution, but the physiological function and activation mechanisms are largely unknown, and its pharmacology is poorly understood. We have generated cell lines expressing NOX4 upon tetracycline induction. Tetracycline induced a rapid increase in NOX4 mRNA (1 h) followed closely (2 h) by a release of ROS. Upon tetracycline withdrawal, NOX4 mRNA levels and ROS release decreased rapidly (100 ?M). The pattern of NOX4-dependent ROS generation was unique: (i) ROS release upon NOX4 induction was spontaneous without need for a stimulus, and (ii) the type of ROS released from NOX4-expressing cells was H2O2, whereas superoxide (O2?) was almost undetectable. Probes that allow detection of intracellular O2? generation yielded differential results: DHE (dihydroethidium) fluorescence and ACP (1-acetoxy-3-carboxy-2,2,5,5-tetramethylpyrrolidine) ESR measurements did not detect any NOX4 signal, whereas a robust signal was observed with NBT. Thus NOX4 probably generates O2? within an intracellular compartment that is accessible to NBT (Nitro Blue Tetrazolium), but not to DHE or ACP. In conclusion, NOX4 has a distinct pharmacology and pattern of ROS generation. The close correlation between NOX4 mRNA and ROS generation might hint towards a function as an inducible NOX isoform. PMID:17501721

Serrander, Lena; Cartier, Laetitia; Bedard, Karen; Banfi, Botond; Lardy, Bernard; Plastre, Olivier; Sienkiewicz, Andrzej; Fórró, Lászlo; Schlegel, Werner; Krause, Karl-Heinz

2007-01-01

234

CysLT1 receptor-induced human airway smooth muscle cells proliferation requires ROS generation, EGF receptor transactivation and ERK1/2 phosphorylation  

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Full Text Available Abstract Background Cysteine-containing leukotrienes (cysteinyl-LTs are pivotal inflammatory mediators that play important roles in the pathophysiology of asthma, allergic rhinitis, and other inflammatory conditions. In particular, cysteinyl-LTs exert a variety of effects with relevance to the aetiology of asthma such as smooth muscle contraction, eosinophil recruitment, increased microvascular permeability, enhanced mucus secretion and decreased mucus transport and, finally, airway smooth muscle cells (ASMC proliferation. We used human ASMC (HASMC to identify the signal transduction pathway(s of the leukotriene D4 (LTD4-induced DNA synthesis. Methods Proliferation of primary HASMC was measured by [3H]thymidine incorporation. Phosphorylation of EGF receptor (EGF-R and ERK1/2 was assessed with a polyclonal anti-EGF-R or anti-phosphoERKl/2 monoclonal antibody. A Ras pull-down assay kit was used to evaluate Ras activation. The production of reactive oxygen species (ROS was estimated by measuring dichlorodihydrofluorescein (DCF oxidation. Results We demonstrate that in HASMC LTD4-stimulated thymidine incorporation and potentiation of EGF-induced mitogenic signaling mostly depends upon EGF-R transactivation through the stimulation of CysLT1-R. Accordingly, we found that LTD4 stimulation was able to trigger the increase of Ras-GTP and, in turn, to activate ERK1/2. We show here that EGF-R transactivation was sensitive to pertussis toxin (PTX and phosphoinositide 3-kinase (PI3K inhibitors and that it occurred independently from Src activity, despite the observation of a strong impairment of LTD4-induced DNA synthesis following Src inhibition. More interestingly, CysLT1-R stimulation increased the production of ROS and N-acetylcysteine (NAC abolished LTD4-induced EGF-R phosphorylation and thymidine incorporation. Conclusion Collectively, our data demonstrate that in HASMC LTD4 stimulation of a Gi/o coupled CysLT1-R triggers the transactivation of the EGF-R through the intervention of PI3K and ROS. While PI3K and ROS involvement is an early event, the activation of Src occurs downstream of EGF-R activation and is followed by the classical Ras-ERK1/2 signaling pathway to control G1 progression and cell proliferation.

Capra Valérie

2006-03-01

235

Ca2+-sensors and ROS-GC: Interlocked sensory transduction elements: A review  

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Full Text Available From its initial discovery that ROS-GC membrane guanylate cyclase is a mono-modal Ca2+-transduction system linked exclusively with the phototransduction machinery to the successive finding that it embodies a remarkable bimodal Ca2+signaling device, its widened transduction role in the general signaling mechanisms of the sensory neuron cells was envisioned. A theoretical concept was proposed where Ca2+-modulates ROS-GC through its generated cyclic GMP via a nearby cyclic nucleotide gated channel and creates a hyper- or depolarized sate in the neuron membrane (Ca2+ Binding Proteins 1:1, 7-11, 2006. The generated electric potential then becomes a mode of transmission of the parent [Ca2+]i signal. Ca2+ and ROS-GC are interlocked messengers in multiple sensory transduction mechanisms. This comprehensive review discusses the developmental stages to the present status of this concept and demonstrates how neuronal Ca2+-sensor proteins are the interconnected elements of this elegant ROS-GC transduction system. The focus is on the dynamism of the structural composition of this system, and how it accommodates selectivity and elasticity for the Ca2+ signals to perform multiple tasks linked with the SENSES of vision, smell and possibly of taste and the pineal gland. An intriguing illustration is provided for the Ca2+ sensor GCAP1 which displays its remarkable ability for its flexibility in function from being a photoreceptor sensor to an odorant receptor sensor. In doing so it reverses its function from an inhibitor of ROS-GC to the stimulator of ONE-GC membrane guanylate cyclase.

RameshwarKSharma

2012-04-01

236

Loss of the tumor suppressor Hace1 leads to ROS-dependent glutamine addiction.  

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Cellular transformation is associated with altered glutamine (Gln) metabolism. Tumor cells utilize Gln in the tricarboxylic acid (TCA) cycle to maintain sufficient pools of biosynthetic precursors to support rapid growth and proliferation. However, Gln metabolism also generates NADPH, and Gln-derived glutamate is used for synthesis of glutathione (GSH). As both NADPH and GSH are antioxidants, Gln may also contribute to redox balance in transformed cells. The Hace1 E3 ligase is a tumor suppressor inactivated in diverse human cancers. Hace1 targets the Rac1 GTPase for degradation at Rac1-dependent NADPH oxidase complexes, blocking superoxide generation by the latter. Consequently, loss of Hace1 increases reactive oxygen species (ROS) levels in vitro and in vivo. Given the link between Hace1 loss and increased ROS, we investigated whether genetic inactivation of Hace1 alters Gln metabolism. We demonstrate that mouse embryonic fibroblasts (MEFs) derived from Hace1(-/-) mice are highly sensitive to Gln withdrawal, leading to enhanced cell death compared with wild-type (wt) MEFs, and Gln depletion or chemical inhibition of Gln uptake blocks soft agar colony formation by Hace1(-/-) MEFs. Hace1(-/-) MEFs exhibit increased Gln uptake and ammonia secretion, and metabolic labeling using (13)C-Gln revealed that Hace1 loss increases incorporation of Gln carbons into the TCA cycle intermediates. Gln starvation markedly increases ROS levels in Hace1(-/-) but not in wt MEFs, and treatment with the antioxidant N-acetyl cysteine or the TCA cycle intermediate oxaloacetate efficiently rescues Gln starvation-induced ROS elevation and cell death in Hace1(-/-) MEFs. Finally, Gln starvation increases superoxide levels in Hace1(-/-) MEFs, and NADPH oxidase inhibitors block the induction of superoxide and cell death by Gln starvation. Together, these results suggest that increased ROS production due to Hace1 loss leads to Gln addiction as a mechanism to cope with increased ROS-induced oxidative stress.Oncogene advance online publication, 6 October 2014; doi:10.1038/onc.2014.316. PMID:25284589

Cetinbas, N; Daugaard, M; Mullen, A R; Hajee, S; Rotblat, B; Lopez, A; Li, A; DeBerardinis, R J; Sorensen, P H

2014-10-01

237

Effect of Iron-Mediated Oxidative Stress on Insulin Resistance Through the Forkhead Box-Containing Protein O Subfamily-1 (FOXO-1) Pathway in Chronic Hepatitis C  

OpenAIRE

Aims: Chronic hepatitis C virus (HCV) infection is often associated with glucose metabolic disorders and iron overload. It has recently been shown that reactive oxygen species (ROS) increase gluconeogenesis in hepatocytes through the forkhead box-containing protein O subfamily-1 (FOXO1)-dependent pathway. The aim of this study is proving a cause-and-effect relationship between iron-mediated ROS production and insulin resistance (IR) in chronic hepatitis C (CH-C) patients. Methods: The study ...

Yoshinao Kobayashi; Motoh Iwasa; Hirohide Miyachi; Ryosuke Sugimoto; Hideaki Tanaka; Rumi Mifuji-Moroka; Naoki Fujita; Yasuhiro Sumida; Yoshiyuki Takei

2013-01-01

238

Sesamol inhibits UVB-induced ROS generation and subsequent oxidative damage in cultured human skin dermal fibroblasts.  

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The exposure of cells to ultraviolet B radiation (UVB) can induce the production of reactive oxygen species (ROS) which damage cellular components. Free radical scavengers and antioxidants can interfere with the production of ROS. We studied cytotoxicity, intracellular ROS levels, lipid peroxidation, antioxidant status and oxidative DNA damage in cultured human skin dermal fibroblast adult cells (HDFa) exposed to UVB in the presence of sesamol, a natural phenolic compound. The levels of cytotoxicity, intracellular ROS, lipid peroxidation, oxidative DNA damage and apoptotic morphological changes were significantly increased in UVB irradiated HDFa cells. We also observed that the activities of enzymatic antioxidants (superoxide dismutase, catalase and glutathione peroxidase) and the levels of non-enzymatic antioxidant status (GSH) were significantly decreased in UVB irradiated cells. On the other hand, sesamol pretreatment significantly decreased cytotoxicity, intracellular ROS, lipid peroxidation, oxidative DNA damage and apoptotic morphological changes in sesamol-pretreated and UVB-irradiated HDFa cells. We have also observed increased enzymatic and non-enzymatic antioxidants status in sesamol plus UVB-irradiated cells. Among the different doses tested, 80 ?M of sesamol shows maximum protection for UVB-induced oxidative damage. In conclusion, UVB-induced ROS formation, cell fatality, lipid peroxidation, antioxidant depletion and oxidative DNA damage in HDFa cells is inhibited by sesamol, which, probably through its ROS scavenging activity. PMID:20697726

Ramachandran, S; Rajendra Prasad, N; Karthikeyan, S

2010-12-01

239

Selenium compounds induce ROS in human high-metastatic large cell lung cancer cell line L9981  

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Full Text Available Background and objective It has been proved that methylseleninic acid (MSA is a kind of artificially developed selenium compound, which appeared to be the best candidate for cancer prevention and therapy. Reduced glutathione is not only critical to MSA metabolism, but also is a kind of protective antioxidant which could remove the oxygen free radical promptly and maintain the intracellular redox status stable. The aim of this study is to explore the anticancer effects of ROS induced by MSA and the molecular mechanisms of MSA on induction of ROS. Methods We confirmed that MSA and selenite have the anticancer effect in the human high-metastatic large cell lung cancer cell line L9981 by growth inhibition detection, we detect the ROS induced by MSA and selenite in L9981 by fluorescence microscopy, and use flow cytometry to quantitate the ROS induced by NAC together with selenium compounds. Results ?MSA 2.5 ?M and 5.0 ?M selenite could inhibit the L9981 growth, Increasing the concentration resulted in a more pronounced effect. ?MSA and selenite could induce ROS in L9981. ?incubated NAC with selenite could significantly inhibit the ROS but increase the ROS treated by NAC with MSA. Conclusions ?MSA and selenite had anti-L9981 effect. ?Oxidative stress reaction may participate in the induction of apoptosis by MSA and selenite in lung cancer cell line L9981.

Chengfei LIU

2008-06-01

240

ROS-responsive microspheres for on demand antioxidant therapy in a model of diabetic peripheral arterial disease.  

Science.gov (United States)

A new microparticle-based delivery system was synthesized from reactive oxygen species (ROS)-responsive poly(propylene sulfide) (PPS) and tested for "on demand" antioxidant therapy. PPS is hydrophobic but undergoes a phase change to become hydrophilic upon oxidation and thus provides a useful platform for ROS-demanded drug release. This platform was tested for delivery of the promising anti-inflammatory and antioxidant therapeutic molecule curcumin, which is currently limited in use in its free form due to poor pharmacokinetic properties. PPS microspheres efficiently encapsulated curcumin through oil-in-water emulsion and provided sustained, on demand release that was modulated in vitro by hydrogen peroxide concentration. The cytocompatible, curcumin-loaded microspheres preferentially targeted and scavenged intracellular ROS in activated macrophages, reduced in vitro cell death in the presence of cytotoxic levels of ROS, and decreased tissue-level ROS in vivo in the diabetic mouse hind limb ischemia model of peripheral arterial disease. Interestingly, due to the ROS scavenging behavior of PPS, the blank microparticles also showed inherent therapeutic properties that were synergistic with the effects of curcumin in these assays. Functionally, local delivery of curcumin-PPS microspheres accelerated recovery from hind limb ischemia in diabetic mice, as demonstrated using non-invasive imaging techniques. This work demonstrates the potential for PPS microspheres as a generalizable vehicle for ROS-demanded drug release and establishes the utility of this platform for improving local curcumin bioavailability for treatment of chronic inflammatory diseases. PMID:25522975

Poole, Kristin M; Nelson, Christopher E; Joshi, Rucha V; Martin, John R; Gupta, Mukesh K; Haws, Skylar C; Kavanaugh, Taylor E; Skala, Melissa C; Duvall, Craig L

2015-02-01

241

Quantitative analyses of ROS and RNS production in breast cancer cell lines incubated with ferrocifens.  

Science.gov (United States)

Ferrocifens are an original class of ferrocifen-type breast cancer drugs. They possess anti-proliferative effects due to the association of the ferrocene moiety and the tamoxifen skeleton. In this work, fluorescence measurements indicated the production of reactive oxygen species (ROS) if hormone-dependent or -independent breast cancer cells were incubated with three hit ferrocifen compounds. Additionally, amperometry at ultramicroelectrodes was carried out to identify and quantify ROS and reactive nitrogen species (RNS) under stress conditions. Videomicroscopy was used to optimize the conditions employed for electrochemical investigations. Amperometry was then performed on two cell lines pre-incubated with each of the three ferrocifens. Interestingly, these results demonstrate that the presence of an aminoalkyl chain in the ferrocifen structure may confer a unique behavior toward both cell lines, in comparison with the two other compounds that lack this feature. PMID:24803138

Lu, Cong; Heldt, Jan-Martin; Guille-Collignon, Manon; Lemaître, Frédéric; Jaouen, Gérard; Vessières, Anne; Amatore, Christian

2014-06-01

242

Mitochondrial localization of TIGAR under hypoxia stimulates HK2 and lowers ROS and cell death.  

Science.gov (United States)

The p53-inducible protein TIGAR (Tp53-induced Glycolysis and Apoptosis Regulator) functions as a fructose-2,6-bisphosphatase (Fru-2,6-BPase), and through promotion of the pentose phosphate pathway, increases NADPH production to help limit reactive oxygen species (ROS). Here, we show that under hypoxia, a fraction of TIGAR protein relocalized to mitochondria and formed a complex with hexokinase 2 (HK2), resulting in an increase in HK2 activity. Mitochondrial localization of TIGAR depended on mitochondrial HK2 and hypoxia-inducible factor 1 (HIF1?) activity. The ability of TIGAR to function as a Fru-2,6-BPase was independent of HK2 binding and mitochondrial localization, although both of these activities can contribute to the full activity of TIGAR in limiting mitochondrial ROS levels and protecting from cell death. PMID:23185017

Cheung, Eric C; Ludwig, Robert L; Vousden, Karen H

2012-12-11

243

A tidal wave of signals: calcium and ROS at the forefront of rapid systemic signaling.  

Science.gov (United States)

Systemic signaling pathways enable multicellular organisms to prepare all of their tissues and cells to an upcoming challenge that may initially only be sensed by a few local cells. They are activated in plants in response to different stimuli including mechanical injury, pathogen infection, and abiotic stresses. Key to the mobilization of systemic signals in higher plants are cell-to-cell communication events that have thus far been mostly unstudied. The recent identification of systemically propagating calcium (Ca(2+)) and reactive oxygen species (ROS) waves in plants has unraveled a new and exciting cell-to-cell communication pathway that, together with electric signals, could provide a working model demonstrating how plant cells transmit long-distance signals via cell-to-cell communication mechanisms. Here, we summarize recent findings on the ROS and Ca(2+) waves and outline a possible model for their integration. PMID:25088679

Gilroy, Simon; Suzuki, Nobuhiro; Miller, Gad; Choi, Won-Gyu; Toyota, Masatsugu; Devireddy, Amith R; Mittler, Ron

2014-10-01

244

Seasonal trends in the composition and ROS activity of fine particulate matter in Baghdad, Iraq  

Science.gov (United States)

Baghdad suffers from severe atmospheric particulate matter (PM) pollution and has limited infrastructure to monitor and control PM-pollution. To help better understand the nature of particulate matter in Baghdad, daily PM2.5 samples were collected every 6th day from September, 2012 to September, 2013. The samples were analyzed for chemical composition and cellular oxidative stress activity using a macrophage-based assay. The annual average PM2.5 concentration was 50 ± 19 ?g m-3, and was comprised of approximately 28% crustal materials, 26% organic carbon (OC), 17% sulfate, 12% elemental carbon (EC), and 8.0% ammonium ion. No clear seasonal trend was observed for the total PM2.5 mass and PM2.5 OC, but EC exhibited higher concentrations in the warmer months, likely due to the extensive use of electric generators operated by diesel and gasoline for cooling. April showed the lowest levels of both EC and OC compared with other months due to both sand and rainstorm events which led to increased deposition and dispersion of local emissions. Concentrations of nitrate ion were low in all seasons due to the high temperatures and low humidity, but slightly higher levels were observed in the cooler months of winter. The oxidative stress (reactive oxygen species (ROS)) activity (59 ± 35 ?g Zymosan equivalents m-3) of the PM was relatively lower than in other studied areas. Association between the water soluble PM constituents and the oxidative activity was investigated using a multi-linear regression model which showed no strong relationships between ROS activity and the water soluble components of PM2.5, but a moderate correlation of water soluble organic carbon from biomass burning (WSOC-BB) was observed (R2 = 0.52). Biomass burning PM has been shown to be an important contributor to ROS activity in other published studies, but additional work is needed to better understand the sources leading to the ROS activity in Baghdad.

Hamad, Samera Hussein; Shafer, Martin Merrill; Kadhim, Ahmed K. H.; Al-Omran, Sabah M.; Schauer, James Jay

2015-01-01

245

ROS and RNS Signaling in Heart Disorders: Could Antioxidant Treatment Be Successful?  

OpenAIRE

There is not too much success in the antioxidant treatment of heart deceases in humans. However a new approach is now developed that suggests that depending on their structures and concentrations antioxidants can exhibit much more complicated functions in many pathological disorders. It is now well established that physiological free radicals superoxide and nitric oxide together with their derivatives hydrogen peroxide and peroxynitrite (all are named reactive oxygen species (ROS) and reactiv...

Igor Afanas'ev

2011-01-01

246

Cryopreservation affects ROS-induced oxidative stress and antioxidant response in Arabidopsis seedlings.  

Science.gov (United States)

Plant recovery status after cryopreservation by vitrification had a negative relationship to the oxidative stress induced by reactive oxygen species (ROS). Arabidopsis thaliana seedlings germinated for 48 h or 72 h with different survival tolerances were examined at five steps of cryopreservation, to determine the role of ROS (O2(-), H2O2 and OH) and antioxidant systems (SOD, POD, CAT, AsA and GSH) in cryo-injury. In addition, the effects of the steps on membrane lipid peroxidation were studied using malondialdehyde (MDA) as an indicator. The results indicated that H2O2-induced oxidative stress at the steps of dehydration and rapid warming was the main cause of cryo-injury of 48-h seedlings (high survival rate) and 72-h seedlings (no survival). The H2O2 was mainly generated in cotyledons, shoot tips and roots of seedlings as indicated by Amplex Red staining. Low survival of 72-h seedlings was associated with severe membrane lipid peroxidation, which was caused by increased OH generation activity and decreased SOD activity. The antioxidant-related gene expression by qRT-PCR and physiological assays suggested that the antioxidant system of 48-h seedlings were activated by ROS, and they mounted a defense against oxidative stress. A high level of ROS led to the weakening of the antioxidant system of 72-h seedlings. Correlation analysis indicated that enhanced antioxidant enzymes activities contributed to the high survival rate of 48-h seedlings, which could reflect by cryopreservation of antioxidant mutant seedlings. This model system indicated that elevated CAT activity and AsA content were determinants of cryogenic stress tolerance, whose manipulation could improve the recovery of seedlings after cryopreservation. PMID:25489814

Chen, Guan-Qun; Ren, Li; Zhang, Jie; Reed, Barbara M; Zhang, Di; Shen, Xiao-Hui

2015-02-01

247

Superparamagnetic Iron Oxide Nanoparticles: Amplifying ROS Stress to Improve Anticancer Drug Efficacy  

OpenAIRE

Superparamagnetic iron oxide nanoparticles (SPION) are an important and versatile nano- platform with broad biological applications. Despite extensive studies, the biological and pharmacological activities of SPION have not been exploited in therapeutic applications. Recently, ?-lapachone (?-lap), a novel anticancer drug, has shown considerable cancer specificity by selectively increasing reactive oxygen species (ROS) stress in cancer cells. In this study, we report that pH-responsive SPION...

Huang, Gang; Chen, Huabing; Dong, Ying; Luo, Xiuquan; Yu, Haijun; Moore, Zachary; Bey, Erik A.; Boothman, David A.; Gao, Jinming

2013-01-01

248

Insulin/IGF-1 and ROS signaling pathway cross-talk in aging and longevity determination  

OpenAIRE

Regulation of hormonal, insulin/IGF-1 (Ins/IGF-1) signaling activities, and pathways of the intrinsic generation of reactive oxygen species (ROS) play a role in aging and longevity determination. In this review we discuss the cross-talk between these pathways as mechanisms of signaling that may be important factors in the regulation of aging and longevity. The balance of physiological processes controlling the rate of aging and longevity in several mouse mutants suggests the involvement of cr...

Papaconstantinou, John

2008-01-01

249

ira_laser_tools: a ROS LaserScan manipulation toolbox  

OpenAIRE

Laser scanners are sensors of widespread use in robotic applications. Under the Robot Operating System (ROS) the information generated by laser scanners can be conveyed by either LaserScan messages or in the form of PointClouds. Many publicly available algorithms (mapping, localization, navigation, etc.) rely on LaserScan messages, yet a tool for handling multiple lasers, merging their measurements, or to generate generic LaserScan messages from PointClouds, is not available...

Ballardini, Augusto Luis; Fontana, Simone; Furlan, Axel; Sorrenti, Domenico G.

2014-01-01

250

Vidurin?s mokyklos mokytojo pedagoginio kompetentingumo turinio ir strukt?ros pagrindimas  

OpenAIRE

Šiuolaikin?s besikei?ian?ios visuomen?s spart?jantys pasikeitimai meta išš?k? mokytojams, j? pedagoginiam kompetentingumui. Mokytojo pedagoginis kompetentingumas ir nuolatinis jo tobulinimas yra pagrindinis veiksnys, lemiantis mokytojo profesin? tobul?jim? ir kokybišk? veikl?. Disertacijoje siekiama išsiaiškinti, koks turi b?ti vidurin?s mokyklos mokytojo pedagoginio kompetentingumo turinio ir strukt?ros modelis, kur? b?t? galima si?lyti kaip mokytojo standarto rengi...

Rodzevic?iu?te?, Emilija

2009-01-01

251

Impact of UV light on the plant cell wall, methane emissions and ROS production  

OpenAIRE

This study presents the first attempt to combine the fields of ultraviolet (UV) photobiology, plant cell wall biochemistry, aerobic methane production and reactive oxygen species (ROS) mechanisms to investigate the effect of UV radiation on vegetation foliage. Following reports of a 17% increase in decomposition rates in oak (Quercus robur) due to increased UV, which were later ascribed to changes in cell wall carbohydrate extractability, this study investigated the effects of ...

Messenger, David James

2009-01-01

252

Intracellular ROS Protection Efficiency and Free Radical-Scavenging Activity of Curcumin  

OpenAIRE

Curcumin has many pharmaceutical applications, many of which arise from its potent antioxidant properties. The present research examined the antioxidant activities of curcumin in polar solvents by a comparative study using ESR, reduction of ferric iron in aqueous medium and intracellular ROS/toxicity assays. ESR data indicated that the steric hindrance among adjacent big size groups within a galvinoxyl molecule limited the curcumin to scavenge galvinoxyl radicals effectively, while curcumin s...

Barzegar, Abolfazl; Moosavi-movahedi, Ali A.

2011-01-01

253

Iron Overload Induced Apoptotic Cell Death in Isolated Rat Hepatocytes Mediated by Reactive Oxygen Species  

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Full Text Available Isolated rat hepatocytes in culture were incubated with different concentrations of iron-sorbitol (50, 100, 150, and 200 µM to assess the changes in reactive oxygen species (ROS and lipid peroxidation leading to apoptotic hepatocyte cell death. The viability of hepatocytes was declined depending on the iron concentration. One hour incubation of the cells with 100 µM iron resulted in decreased of the hepatocyte viability down to 50% (EC50 µM. Cellular glutathione (GSH was depleted depending on the concentration of iron added to the hepatocytes in culture. Decline in cellular GSH was associated with elevation in reactive oxygen species (ROS generation and formation of thiobarbituric acid reactive substances (TBARS as index of lipid peroxidation. TBARS concentration was elevated in hepatocytes exposed to >100 µM of iron for 40 min. A significant increase in ROS formation was also observed in cells incubated with 75 µM of iron for 60 and 120 min. The consequences of ROS-mediated damages to hepatocytes were observed by DNA fragmentation, nuclear staining by propidium iddide and finally with induction of apoptotic hepatocyte cell death. Terminal deoxynucleotie transferase-mediated dUTP nick end labeling i.e. TUNEL assay (In situ- cell death-detection kit and nuclear staining were also used to confirm apoptosis. These data clearly show that iron overload can cause apoptotic cell death in isolated hepatocytes and generation of ROS precedes other changes related to oxidative stress.

Abdolamir Allameh

2008-01-01

254

Cu-Zn Slags from R?ros (Norway): A Case Study of Rapid Cooling and Crystal Nucleation  

Science.gov (United States)

The mining town of R?ros located in central Norway was established in 1644 and it is known of historical mining industry related to copper. R?ros was designated as an UNESCO World Heritage Site in 1980 on the base of mining culture represented by, e.g., unique wooden architecture. Slag pieces are composed of three parts differing in glass to crystallites ratio. R?ros slags are composed of olivine- and pyroxene- group minerals accompanied by sulphides, with glass in the interstices. Temperature gradient and volatiles content were determined as the main factor influencing crystallization process in this material.

Warchulski, Rafa?; Szopa, Krzysztof

2014-09-01

255

Protoporphyrin IX-dependent photodynamic production of endogenous ROS stimulates cell proliferation  

DEFF Research Database (Denmark)

Photodynamic therapy using methyl 5-aminolevulinate (MAL) as a precursor of the photosensitizing agent protoporphyrin IX is widely used in clinical practice for the treatment of different pathologies, including cancer. In this therapeutic modality, MAL treatment promotes the forced accumulation of the endogenous photoactive compound protoporphyrin IX in target malignant cells. Subsequent irradiation of treated tissues with an appropriate visible light source induces the production of reactive oxygen species (ROS) that, once accumulated above a critical level, promote cell death. Here we demonstrate that a photodynamic treatment with low MAL concentrations can be used to promote a moderate production of endogenous ROS, which efficiently stimulates cell growth in human immortalized keratinocytes (HaCaT). We also show that this proliferative response requires Src kinase activity and is associated to a transient induction of cyclin D1 expression. Taken together, these results demonstrate for the first time that acombination of light and a photoactive compound can be used to modulate cell cycle progression through Src kinase activation and that a moderate intracellular increase of photogenerated ROS efficiently stimulates cell proliferation.

Blazquez-Castro, Alfonso; Carrasco, Elisa

2012-01-01

256

Influence of thiol stress on oxidative phosphorylation and generation of ROS in Streptomyces coelicolor  

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Full Text Available Thiols play very important role in the intracellular redox homeostasis. Imbalance in the redox status leads to changes in the intracellular metabolism including respiration. Thiol stress, a reductive type of stress can also cause redox imbalance. When Gram-positive bacterium Strep- tomyces coelicolor was exposed to thiol stress, catalaseA was induced. Induction of catalaseA is the consequence of elevation of ROS (reactive oxygen species. The two major sources of reactive oxygen species are Fenton reaction and slippage of electrons from electron transport chain during respiration. Hence, the effect of thiol stress was checked on the rate of oxidative phosphorylation in S. coelicolor. We found correlation in the increase of oxidative phosphorylation rate and the generation of ROS, subsequently leading to induction of catalase. It was observed that thiol stress does not affect the functionality of the individual complexes of the ETC, but still there was an increase in the overall respiration, which may lead to generation of more ROS leading to induction of catalase.

Hemendra J. Vekaria

2010-11-01

257

High selenium impairs hepatic insulin sensitivity through opposite regulation of ROS.  

Science.gov (United States)

Insulin resistance is the hallmark of type 2 diabetes. As an essential trace element, selenium (Se) is recommended worldwide for supplementation to prevent Se-deficient pathological conditions, including diabetes and insulin resistance. However, recent evidence has shown that supra-nutritional Se intake is positively associated with the prevalence of diabetes. In the present research, we examined the effect of high Se on insulin sensitivity, and studied possible mechanisms in rats and in rat hepatocytes. Insulin sensitivity and glucose/lipid metabolism were determined by glucose/insulin tolerance test, western blot, immunofluorescence, specific probes and other biochemical assays. We show that high Se activates selenoproteins, including glutathione peroxidase and selenoprotein P, and depletes chromium, leading to a common metabolic intersection-lipolysis in adipose tissue and influx of fatty acids in liver. Fatty acid ?-oxidation generates acetyl-CoA, which is metabolized in trichloroacetic acid cycle, supplying excessive electrons for mitochondrial oxidative phosphorylation and leading to increased "bad" reactive oxygen species (ROS) production in mitochondria and final disturbance of insulin signaling. Furthermore, high Se-activated selenoproteins also weaken insulin-stimulated "good" ROS signal generated by NAD(P)H oxidase, leading to attenuation of insulin signaling. Taken together, these data suggest that excessive intake of Se induces hepatic insulin resistance through opposite regulation of ROS. PMID:24140496

Wang, Xin; Zhang, Wei; Chen, Hongli; Liao, Nai; Wang, Zhao; Zhang, Xiaodi; Hai, Chunxu

2014-01-01

258

Citreoviridin induces ROS-dependent autophagic cell death in human liver HepG2 cells.  

Science.gov (United States)

Citreoviridin (CIT) is one of toxic mycotoxins derived from fungal species in moldy cereals. Whether CIT exerts hepatotoxicity and the precise molecular mechanisms of CIT hepatotoxicity are not completely elucidated. In this study, the inhibitor of autophagosome formation, 3-methyladenine, protected the cells against CIT cytotoxicity, and the autophagy stimulator rapamycin further decreased the cell viability of CIT-treated HepG2 cells. Knockdown of Atg5 with Atg5 siRNA alleviated CIT-induced cell death. These finding suggested the hypothesis that autophagic cell death contributed to CIT-induced cytotoxicity in HepG2 cells. CIT increased the autophagosome number in HepG2 cells observed under a transmission electron microscope, and this effect was confirmed by the elevated LC3-II levels detected through Western blot. Reduction of P62 protein levels and the result of LC3 turnover assay indicated that the accumulation of autophagosomes in the CIT-treated HepG2 cells was due to increased formation rather than impaired degradation. The pretreatment of HepG2 cells with the ROS inhibitor NAC reduced autophagosome formation and reversed the CIT cytotoxicity, indicating that CIT-induced autophagic cell death was ROS-dependent. In summary, ROS-dependent autophagic cell death of HpeG2 cells described in this study may help to elucidate the underlying mechanism of CIT cytotoxicity. PMID:25553592

Liu, Ya-Nan; Wang, Yue-Xia; Liu, Xiao-Fang; Jiang, Li-Ping; Yang, Guang; Sun, Xian-Ce; Geng, Cheng-Yan; Li, Qiu-Juan; Chen, Min; Yao, Xiao-Feng

2015-03-01

259

Caspase inhibition augments Dichlorvos-induced dopaminergic neuronal cell death by increasing ROS production and PARP1 activation.  

Science.gov (United States)

Numerous epidemiological studies have shown an association between pesticide exposure and the increased risk of developing Parkinson's disease. Previously we have reported that Dichlorvos exposure can induce oxidative stress, resulting in over-expression of pro-apoptotic genes and finally caspase-dependent nigrostriatal dopaminergic neuronal cell death in rat brain. Here, we examined the effect of caspase inhibition on PC12 cell death induced by Dichlorvos (30 ?M). Reactive oxygen species (ROS) generation followed by protein carbonylation, lipid peroxidation, decreased antioxidant defenses (decreased Mn-superoxide dismutase (MnSOD) activity and decreased glutathione levels) and subsequent caspase activation mediated the apoptosis. Inhibition of caspase cascade with Boc-aspartyl(OMe)-fluoromethylketone (BAF) enhanced the Dichlorvos-induced PC12 cell death, as assessed by the increased cellular efflux of lactate dehydrogenase (LDH). This increase in cell death was accompanied by a marked increase in poly(ADP-ribose) polymerase-1 (PARP1) activity, increased oxidative stress, a reduction in the mitochondrial membrane potential and reduced cellular NAD and ATP levels. Pretreatment of cells with PJ34, a PARP1 inhibitor prevented the cells from undergoing cell death and preserved intracellular NAD and ATP levels. Subsequent release of the apoptosis-inducing factor (AIF) from mitochondria and its translocation into the nucleus was also prevented by PJ34 pretreatment. In conclusion, the results of the present study show that caspase inhibition without concurrent inhibition of PARP1 is unlikely to be effective in preventing cell death because in the presence of the caspase inhibitor, caspase-independent cell death predominates due to PARP activation. These results suggest that combined therapeutic strategies directed at multiple cell death pathways may provide superior neuroprotection than those directed at a single mechanism. PMID:24231740

Wani, W Y; Sunkaria, A; Sharma, D R; Kandimalla, R J L; Kaushal, A; Gerace, E; Chiarugi, A; Gill, K D

2014-01-31

260

N-acetylcysteine attenuates reactive-oxygen-species-mediated endoplasmic reticulum stress during liver ischemia-reperfusion injury  

Science.gov (United States)

AIM: To investigate the effects of N-acetylcysteine (NAC) on endoplasmic reticulum (ER) stress and tissue injury during liver ischemia reperfusion injury (IRI). METHODS: Mice were injected with NAC (300 mg/kg) intraperitoneally 2 h before ischemia. Real-time polymerase chain reaction and western blotting determined ER stress molecules (GRP78, ATF4 and CHOP). To analyze the role of NAC in reactive oxygen species (ROS)-mediated ER stress and apoptosis, lactate dehydrogenase (LDH) was examined in cultured hepatocytes treated by H2O2 or thapsigargin (TG). RESULTS: NAC treatment significantly reduced the level of ROS and attenuated ROS-induced liver injury after IRI, based on glutathione, malondialdehyde, serum alanine aminotransferase levels, and histopathology. ROS-mediated ER stress was significantly inhibited in NAC-treated mice. In addition, NAC treatment significantly reduced caspase-3 activity and apoptosis after reperfusion, which correlated with the protein expression of Bcl-2 and Bcl-xl. Similarly, NAC treatment significantly inhibited LDH release from hepatocytes treated by H2O2 or TG. CONCLUSION: This study provides new evidence for the protective effects of NAC treatment on hepatocytes during IRI. Through inhibition of ROS-mediated ER stress, NAC may be critical to inhibit the ER-stress-related apoptosis pathway. PMID:25386077

Sun, Yong; Pu, Li-Yong; Lu, Ling; Wang, Xue-Hao; Zhang, Feng; Rao, Jian-Hua

2014-01-01

261

ROS-mediated amplification of AKT/mTOR signalling pathway leads to myeloproliferative syndrome in Foxo3?/? mice  

OpenAIRE

This work reports a novel myeloid progenitor phenotype in Foxo3a-deficient mice that exhibit increased reactive oxygen species signalling and reduced expression of Lnk, a negative regulator of mitogenic cytokine signalling. Thus, the paper unveils a molecular link from Foxo3a deficiency to malignant progression.

Yalcin, Safak; Marinkovic, Dragan; Mungamuri, Sathish Kumar; Zhang, Xin; Tong, Wei; Sellers, Rani; Ghaffari, Saghi

2010-01-01

262

Mentha piperita essential oil induces apoptosis in yeast associated with both cytosolic and mitochondrial ROS-mediated damage.  

Science.gov (United States)

Mentha piperita (MP), also known as peppermint, is an aromatic and medicinal plant widely used in the food industry, perfumery and cosmetic, pharmacy and traditional medicine. Its essential oil (EO) displays antimicrobial activity against a range of bacteria and fungi. In this study, we found that MP EO lethal cytotoxicity is associated with increased levels of intracellular reactive oxygen species, mitochondrial fragmentation and chromatin condensation, without loss of the plasma membrane integrity, indicative of an apoptotic process. Overexpression of cytosolic catalase and superoxide dismutases reverted the lethal effects of the EO and of its major component menthol. Conversely, deficiency in Sod1p (cytosolic copper-zinc-superoxide dismutase) greatly increased sensitivity to both agents, but deficiency in Sod2p (mitochondrial manganese superoxide dismutase) only induced sensitivity under respiratory growth conditions. Mentha piperita EO increased the frequency of respiratory deficient mutants indicative of damage to the mitochondrial genome, although increase in mitochondrial thiol oxidation does not seem to be involved in the EO toxicity. PMID:25065265

Ferreira, Patrícia; Cardoso, Teresa; Ferreira, Filipa; Fernandes-Ferreira, Manuel; Piper, Peter; Sousa, Maria João

2014-11-01

263

Sodium fluoride induces apoptosis in mouse embryonic stem cells through ROS-dependent and caspase- and JNK-mediated pathways  

OpenAIRE

Sodium fluoride (NaF) is used as a source of fluoride ions in diverse applications. Fluoride salt is an effective prophylactic for dental caries and is an essential element required for bone health. However, fluoride is known to cause cytotoxicity in a concentration-dependent manner. Further, no information is available on the effects of NaF on mouse embryonic stem cells (mESCs). We investigated the mode of cell death induced by NaF and the mechanisms involved. NaF treatment greater than 1 mM...

Ngoc, Tam Dan Nguyen; Son, Young-ok; Lim, Shin-saeng; Shi, Xianglin; Kim, Jong-ghee; Heo, Jung Sun; Choe, Youngji; Jeon, Young-mi; Lee, Jeong-chae

2012-01-01

264

Using copper ions to amplify ROS-mediated fluorescence for continuous online monitoring of extracellular glucose in living rat brain.  

Science.gov (United States)

In this study we developed a facile and sensitive method for continuous monitoring of extracellular glucose concentration in living rat brain through microdialysis (MD) sampling in conjunction with (i) online sample derivatization using glucose oxidase to generate H2O2, which converted a reactive oxygen species-responsive fluorescent dye, 2',7'-dichlorodihydrofluorescein (DCFH), into fluorescent species, and (ii) a novel non-immobilized enzyme-based fluorescence assay strategy, featuring copper ion (Cu(2+))-facilitated amplification of the fluorescence intensity. After evaluating the experimental conditions for glucose oxidation and fluorescence generation, the introduction of Cu(2+) ions to this system resulted in an additional 51-fold amplification of the net fluorescence intensity. By sequentially loading brain microdialysate into the dual sample collection loops, the sampling frequency was 7.5h(-1). Based on a 40-?L sample volume, the system's detection limit reached as low as 0.18 mM, sufficiently accurate to determine the extracellular glucose concentrations in living rat brains. To demonstrate the proposed system's practical performance and applicability, we conducted (i) spike analyses of biomolecule-rich fetal bovine serum sample, confirming that the analytical reliability was similar to that of a commercial glucose kit, and (ii) in vivo dynamic monitoring of the extracellular glucose concentrations in living rat brains after inducing neural depolarization by perfusing a high-K(+) medium from the MD probe. PMID:25310485

Su, Cheng-Kuan; Chen, Chen-Yu; Tseng, Po-Jen; Sun, Yuh-Chang

2015-02-15

265

Boswellia ovalifoliolata abrogates ROS mediated NF-?B activation, causes apoptosis and chemosensitization in Triple Negative Breast Cancer cells.  

Science.gov (United States)

The present study was aimed to evaluvate the apoptogenic potential of ethanolic extract of leaves from Boswellia ovalifoliolata (BL EthOH) and to unravel the molecular mechanisms implicated in apoptosis of Triple Negative Breast Cancer (TNBC) cells. BL EthOH was cytotoxic against TNBC cells like MDA-MB-231 and MDA-MB-453 with IC?? concentrations 67.48 ± 5.45 and 70.03 ± 4.76 ?g/ml, respectively. Apoptotic studies showed that BL EthOH was able to induce apoptosis and western blot studies demonstrated that BL EthOH significantly decreased the Phospho-NF-?B (ser536), PCNA, anti-apoptotic protein Bcl-2 expression and increased the expression of pro-apoptotic protein Bax, in MDA-MB-231 and MDA-MB-453 cell lines when compared with untreated cells. Besides, BL EthOH has synergistic chemosensitizing effects on TNBC cells and increased the cytotoxicity of doxorubicin and cisplatin. PMID:24908637

Thummuri, Dinesh; Jeengar, Manish Kumar; Shrivastava, Shweta; Areti, Aparna; Yerra, Veera Ganesh; Yamjala, Samyuktha; Komirishetty, Prashanth; Naidu, V G M; Kumar, Ashutosh; Sistla, Ramakrishna

2014-07-01

266

Toward real-time regional earthquake simulation II: Real-time Online earthquake Simulation (ROS) of Taiwan earthquakes  

Science.gov (United States)

We developed a Real-time Online earthquake Simulation system (ROS) to simulate regional earthquakes in Taiwan. The ROS uses a centroid moment tensor solution of seismic events from a Real-time Moment Tensor monitoring system (RMT), which provides all the point source parameters including the event origin time, hypocentral location, moment magnitude and focal mechanism within 2 min after the occurrence of an earthquake. Then, all of the source parameters are automatically forwarded to the ROS to perform an earthquake simulation, which is based on a spectral-element method (SEM). A new island-wide, high resolution SEM mesh model is developed for the whole Taiwan in this study. We have improved SEM mesh quality by introducing a thin high-resolution mesh layer near the surface to accommodate steep and rapidly varying topography. The mesh for the shallow sedimentary basin is adjusted to reflect its complex geometry and sharp lateral velocity contrasts. The grid resolution at the surface is about 545 m, which is sufficient to resolve topography and tomography data for simulations accurate up to 1.0 Hz. The ROS is also an infrastructural service, making online earthquake simulation feasible. Users can conduct their own earthquake simulation by providing a set of source parameters through the ROS webpage. For visualization, a ShakeMovie and ShakeMap are produced during the simulation. The time needed for one event is roughly 3 min for a 70 s ground motion simulation. The ROS is operated online at the Institute of Earth Sciences, Academia Sinica (http://ros.earth.sinica.edu.tw/). Our long-term goal for the ROS system is to contribute to public earth science outreach and to realize seismic ground motion prediction in real-time.

Lee, Shiann-Jong; Liu, Qinya; Tromp, Jeroen; Komatitsch, Dimitri; Liang, Wen-Tzong; Huang, Bor-Shouh

2014-06-01

267

Control of reactive oxygen species (ROS) production through histidine kinases in Aspergillus nidulans under different growth conditions?  

OpenAIRE

Sensor histidine kinases (HKs) are important factors that control cellular growth in response to environmental conditions. The expression of 15 HKs from Aspergillus nidulans was analyzed by quantitative real-time PCR under vegetative, asexual, and sexual growth conditions. Most HKs were highly expressed during asexual growth. All HK gene-disrupted strains produced reactive oxygen species (ROS). Three HKs are involved in the control of ROS: HysA was the most abundant under the restricted oxyge...

Hayashi, Saki; Yoshioka, Megumi; Matsui, Tetsuji; Kojima, Kensuke; Kato, Masashi; Kanamaru, Kyoko; Kobayashi, Tetsuo

2014-01-01

268

Generation of reactive oxygen species (ROS) is a key factor for stimulation of macrophage proliferation by ceramide 1-phosphate  

Energy Technology Data Exchange (ETDEWEB)

We previously demonstrated that ceramide 1-phosphate (C1P) is mitogenic for fibroblasts and macrophages. However, the mechanisms involved in this action were only partially described. Here, we demonstrate that C1P stimulates reactive oxygen species (ROS) formation in primary bone marrow-derived macrophages, and that ROS are required for the mitogenic effect of C1P. ROS production was dependent upon prior activation of NADPH oxidase by C1P, which was determined by measuring phosphorylation of the p40phox subunit and translocation of p47phox from the cytosol to the plasma membrane. In addition, C1P activated cytosolic calcium-dependent phospholipase A{sub 2} and protein kinase C-{alpha}, and NADPH oxidase activation was blocked by selective inhibitors of these enzymes. These inhibitors, and inhibitors of ROS production, blocked the mitogenic effect of C1P. By using BHNB-C1P (a photolabile caged-C1P analog), we demonstrate that all of these C1P actions are caused by intracellular C1P. It can be concluded that the enzyme responsible for C1P-stimulated ROS generation in bone marrow-derived macrophages is NADPH oxidase, and that this enzyme is downstream of PKC-{alpha} and cPLA{sub 2}-{alpha} in this pathway. -- Highlights: Black-Right-Pointing-Pointer Ceramide 1-phosphate (C1P) stimulates reactive oxygen species (ROS) formation. Black-Right-Pointing-Pointer The enzyme responsible for ROS generation by C1P in macrophages is NADPH oxidase. Black-Right-Pointing-Pointer NADPH oxidase lies downstream of cPLA{sub 2}-{alpha} and PKC-{alpha} in this pathway. Black-Right-Pointing-Pointer ROS generation is essential for the stimulation of macrophage proliferation by C1P.

Arana, Lide; Gangoiti, Patricia; Ouro, Alberto; Rivera, Io-Guane; Ordonez, Marta; Trueba, Miguel [Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, University of the Basque Country, 48080 Bilbao (Spain); Lankalapalli, Ravi S.; Bittman, Robert [Department of Chemistry and Biochemistry, Queens College of The City University of New York, Flushing, NY 11367-1597 (United States); Gomez-Munoz, Antonio, E-mail: antonio.gomez@ehu.es [Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, University of the Basque Country, 48080 Bilbao (Spain)

2012-02-15

269

Generation of reactive oxygen species (ROS) is a key factor for stimulation of macrophage proliferation by ceramide 1-phosphate  

International Nuclear Information System (INIS)

We previously demonstrated that ceramide 1-phosphate (C1P) is mitogenic for fibroblasts and macrophages. However, the mechanisms involved in this action were only partially described. Here, we demonstrate that C1P stimulates reactive oxygen species (ROS) formation in primary bone marrow-derived macrophages, and that ROS are required for the mitogenic effect of C1P. ROS production was dependent upon prior activation of NADPH oxidase by C1P, which was determined by measuring phosphorylation of the p40phox subunit and translocation of p47phox from the cytosol to the plasma membrane. In addition, C1P activated cytosolic calcium-dependent phospholipase A2 and protein kinase C-?, and NADPH oxidase activation was blocked by selective inhibitors of these enzymes. These inhibitors, and inhibitors of ROS production, blocked the mitogenic effect of C1P. By using BHNB-C1P (a photolabile caged-C1P analog), we demonstrate that all of these C1P actions are caused by intracellular C1P. It can be concluded that the enzyme responsible for C1P-stimulated ROS generation in bone marrow-derived macrophages is NADPH oxidase, and that this enzyme is downstream of PKC-? and cPLA2-? in this pathway. -- Highlights: ? Ceramide 1-phosphate (C1P) stimulates reactive oxygen species (ROS) formation. ? The enzyme responsible for ROS generation by C1P in macrophages is NADPH oxidase. ? NADPH oxidase lies downstream of cPLA2-? and PKC-? in this pathway. ? ROS generation is essential for the stimulation of macrophage proliferation by C1P.

270

Induction of specific micro RNA (miRNA) species by ROS-generating metal sulfates in primary human brain cells  

OpenAIRE

Iron- and aluminum-sulfate together, at nanomolar concentrations, trigger the production of reactive oxygen species (ROS) in cultures of human brain cells. Previous studies have shown that following ROS induction, a family of pathogenic brain genes that promote inflammatory signalling, cellular apoptosis and brain cell death is significantly over-expressed. Notably, iron- and aluminum-sulfate induce genes in cultured human brain cells that exhibit expression patterns similar to those observed...

Lukiw, Walter J.; Pogue, Aileen I.

2007-01-01

271

Modulation of rosR Expression and Exopolysaccharide Production in Rhizobium leguminosarum bv. trifolii by Phosphate and Clover Root Exudates  

Directory of Open Access Journals (Sweden)

Full Text Available The acidic exopolysaccharide (EPS secreted in large amounts by the symbiotic nitrogen-fixing bacterium Rhizobium leguminosarum bv. trifolii is required for the establishment of an effective symbiosis with the host plant Trifolium spp. EPS biosynthesis in rhizobia is a very complex process regulated at both transcriptional and post-transcriptional levels and influenced by various nutritional and environmental conditions. The R. leguminosarum bv. trifolii rosR gene encodes a transcriptional regulator with a C2H2 type zinc-finger motif involved in positive regulation of EPS synthesis. In silico sequence analysis of the 450-bp long rosR upstream region revealed the presence of several inverted repeats (IR1 to IR6 and motifs with significant identity to consensus sequences recognized by PhoB and LysR-type proteins associated with phosphate- and flavonoid-dependent gene regulation in R. leguminosarum. Using a set of sequentially truncated rosR-lacZ transcriptional fusions, the role of the individual motifs and the effect of phosphate and clover root exudates on rosR expression were established. In addition, the significance of IR4 inverted repeats in the repression, and P2–10 hexamer in the activation of rosR transcription, respectively, was found. The expression of rosR increased in the presence of phosphate (0.1–20 mM and clover root exudates (10 ?M. PHO boxes and the LysR motif located upstream of the rosR translation start site were engaged in the regulation of rosR transcription. The synthesis of EPS and biofilm formation decreased at high phosphate concentrations, but increased in the presence of clover root exudates, indicating a complex regulation of these processes.

Anna Skorupska

2011-06-01

272

Co-occurrence of tetraspanin and ROS generators: Conservation in protein cross-linking and other developmental processes  

OpenAIRE

The nematode exoskeleton, commonly called the cuticle, is a highly structured extracellular matrix mainly composed of collagen. Secreted collagen molecules from the underlying epidermal cells are cross-linked via their tyrosyl residues. Reactive oxygen species (ROS) are required for the cross-linking reaction to produce tyrosyl radicals. The conserved ROS generator enzyme in C. elegans, BLI-3/CeDUOX1, a homolog of dual oxidases (DUOXs), is responsible for production of hydrogen peroxide. The ...

Moribe, Hiroki; Mekada, Eisuke

2013-01-01

273

Ca2+-modulated ROS-GC1 transduction system in testes and its presence in the spermatogenic cells  

Directory of Open Access Journals (Sweden)

Full Text Available ROS-GC1 belongs to the Ca2+-modulated sub-family of membrane guanylate cyclases. It primarily exists and is linked with signaling of the sensory neurons – sight, smell, taste and pinealocytes. Exceptionally, it is also present and is Ca2+-modulated in the non-neuronal cells, the sperm cells in the testes, where S100B protein serves its Ca2+ sensor. The present report demonstrates the identification of an additional Ca2+ sensor of ROS-GC1 in the testes, neurocalcin ?. Through mouse molecular genetic models, it compares and quantifies the relative input of the S100B and neurocalcin ? in regulating the Ca2+ signaling of ROS-GC1 transduction machinery, and via immunochemistry it demonstrates the co-presence of neurocalcin ? and ROS-GC1 in the spermatogenic cells of the testes. The suggestion is that in more ways than one the Ca2+-modulated ROS-GC1 transduction system is linked with the testicular function. This non-neuronal transduction system may represent an illustration of the ROS-GC1 expanding role in the trans-signaling of the neural and non-neural systems.

Anna Jankowska

2014-04-01

274

Generation of highly-reactive oxygen species (hROS) is closely related to hair cell damage in rat organ of Corti treated with gentamicin  

Science.gov (United States)

Reactive oxygen species (ROS) have been suggested to play a major role in aminoglycoside-induced hair cell (HC) loss, but are difficult to detect. Moreover, ROS can occur normally in cells where they have roles in metabolism, cell signaling and other processes. Two new probes, aminophenyl fluorescein (APF) and hydroxyphenyl fluorescein (HPF) are dyes which selectively detect highly-reactive oxygen species (hROS), those most associated with cellular damage. We assessed the presence of hROS in the neonatal rat organ of Corti during chronic exposure to 50 ?M gentamicin in vitro, to examine the relationship between cell damage and hROS across HC type and across the three cochlear turns. hROS were initially detected at 48 hours (h), with an increase at 72 h and persistence until at least 96 h. At 48 h, hROS were restricted to outer HCs and occurred prior to loss of stereocilia. At 72 h, outer HCs showed both hROS and stereocilia loss, and hROS were noted in a few inner HCs. Basal turn HCs showed more hROS than middle turn HCs. Very little hROS accumulation or stereocilia loss was observed in the apical turn, even at 72 h. First row outer HCs were most vulnerable to gentamicin-induced hROS, followed by second and then third row outer HCs. Inner HCs behaved similarly to third row outer HCs. By 96 h stereocilia damage was extensive, but surviving HCs showed persisting fluorescence. APF consistently showed more fluorescence than HPF. The results suggest that hROS accumulation is an important initial step in gentamicin-induced HC damage, and that the differential sensitivity of HCs in the organ of Corti is closely related to differences in hROS accumulation. PMID:19318119

Choung, YH; Taura, A.; Pak, K.; Choi, SJ; Masuda, M.; Ryan, A.F.

2009-01-01

275

The involvement of TLR2 in cytokine and reactive oxygen species (ROS) production by PBMCs in response to Leishmania major phosphoglycans (PGs).  

Science.gov (United States)

In the present study, we show for the first time that lipophosphoglycan (LPG) stimulated cytokine production by human peripheral blood mononuclear cells is also mediated via Toll-like receptor (TLR2). In addition, in order to verify if TLR2 is involved in recognition of the purified PGs, neutralizing mAbs against TLR2 and TLR4 were used to treat the cells before being stimulated with PGs. We found strong Th1-promoting cytokines induced by sLPG but not by mLPG which was blocked by presence of anti-TLR2 mAb. This finding reveals a mechanism by which the first encounter and recognition of L. major promastigotes by mLPG after interaction with TLR2 provides a cytokine milieu for consequent Th2 differentiation. Moreover, having shown the strong induction of Th1-promoting cytokines and low production of IL-10 in response to sLPG might have vaccine implication since it is recognized by TLR2 providing signals to professional antigen presenting cells that reside in the skin to promote effective T cell responses against Leishmania infection. In addition, it was shown that purified mLPG and sLPG activate reactive oxygen species (ROS) production which is also blocked by anti-TLR2 but not by anti-TLR4. However, no inhibition was seen in PPG-induced cytokine and ROS production in the presence of anti-TLR2 and anti-TLR4, implying involvement of other receptors. PMID:19631014

Kavoosi, G; Ardestani, S K; Kariminia, A

2009-09-01

276

Ethanol increases matrix metalloproteinase-12 expression via NADPH oxidase-dependent ROS production in macrophages.  

Science.gov (United States)

Matrix metalloproteinase-12 (MMP-12), an enzyme responsible for degradation of extracellular matrix, plays an important role in the progression of various diseases, including inflammation and fibrosis. Although most of those are pathogenic conditions induced by ethanol ingestion, the effect of ethanol on MMP-12 has not been explored. In the present study, we investigated the effect of ethanol on MMP-12 expression and its potential mechanisms in macrophages. Here, we demonstrated that ethanol treatment increased MMP-12 expression in primary murine peritoneal macrophages and RAW 264.7 macrophages at both mRNA and protein levels. Ethanol treatment also significantly increased the activity of nicotinamide adenine dinucleotide (NADPH) oxidase and the expression of NADPH oxidase-2 (Nox2). Pretreatment with an anti-oxidant (N-acetyl cysteine) or a selective inhibitor of NADPH oxidase (diphenyleneiodonium chloride (DPI)) prevented ethanol-induced MMP-12 expression. Furthermore, knockdown of Nox2 by small interfering RNA (siRNA) prevented ethanol-induced ROS production and MMP-12 expression in RAW 264.7 macrophages, indicating a critical role for Nox2 in ethanol-induced intracellular ROS production and MMP-12 expression in macrophages. We also showed that ethanol-induced Nox2 expression was suppressed by transient transfection with dominant negative I?B-? plasmid or pretreatment with Bay 11-7082, a selective inhibitor of NF-?B, in RAW 264.7 macrophages. In addition, ethanol-induced Nox2 expression was also attenuated by treatment with a selective inhibitor of p38 MAPK, suggesting involvement of p38 MAPK/NF-?B pathway in ethanol-induced Nox2 expression. Taken together, these results demonstrate that ethanol treatment elicited increase in MMP-12 expression via increase in ROS production derived from Nox2 in macrophages. PMID:23978445

Kim, Mi Jin; Nepal, Saroj; Lee, Eung-Seok; Jeong, Tae Cheon; Kim, Sang-Hyun; Park, Pil-Hoon

2013-11-15

277

Ethanol increases matrix metalloproteinase-12 expression via NADPH oxidase-dependent ROS production in macrophages  

Energy Technology Data Exchange (ETDEWEB)

Matrix metalloproteinase-12 (MMP-12), an enzyme responsible for degradation of extracellular matrix, plays an important role in the progression of various diseases, including inflammation and fibrosis. Although most of those are pathogenic conditions induced by ethanol ingestion, the effect of ethanol on MMP-12 has not been explored. In the present study, we investigated the effect of ethanol on MMP-12 expression and its potential mechanisms in macrophages. Here, we demonstrated that ethanol treatment increased MMP-12 expression in primary murine peritoneal macrophages and RAW 264.7 macrophages at both mRNA and protein levels. Ethanol treatment also significantly increased the activity of nicotinamide adenine dinucleotide (NADPH) oxidase and the expression of NADPH oxidase-2 (Nox2). Pretreatment with an anti-oxidant (N-acetyl cysteine) or a selective inhibitor of NADPH oxidase (diphenyleneiodonium chloride (DPI)) prevented ethanol-induced MMP-12 expression. Furthermore, knockdown of Nox2 by small interfering RNA (siRNA) prevented ethanol-induced ROS production and MMP-12 expression in RAW 264.7 macrophages, indicating a critical role for Nox2 in ethanol-induced intracellular ROS production and MMP-12 expression in macrophages. We also showed that ethanol-induced Nox2 expression was suppressed by transient transfection with dominant negative I?B-? plasmid or pretreatment with Bay 11-7082, a selective inhibitor of NF-?B, in RAW 264.7 macrophages. In addition, ethanol-induced Nox2 expression was also attenuated by treatment with a selective inhibitor of p38 MAPK, suggesting involvement of p38 MAPK/NF-?B pathway in ethanol-induced Nox2 expression. Taken together, these results demonstrate that ethanol treatment elicited increase in MMP-12 expression via increase in ROS production derived from Nox2 in macrophages. - Highlights: • Ethanol increases ROS production through up-regulation of Nox2 in macrophages. • Enhanced oxidative stress contributes to ethanol-induced MMP-12 expression. • p38 MAPK/NF-?B signaling pathway modulates ethanol-induced Nox2 expression.

Kim, Mi Jin; Nepal, Saroj; Lee, Eung-Seok; Jeong, Tae Cheon [College of Pharmacy, Yeungnam University, Gyeongsanbuk-do 712-749 (Korea, Republic of); Kim, Sang-Hyun [Department of Pharmacology, School of Medicine, Kyungpook National University, Daegu 700-422 (Korea, Republic of); Park, Pil-Hoon, E-mail: parkp@yu.ac.kr [College of Pharmacy, Yeungnam University, Gyeongsanbuk-do 712-749 (Korea, Republic of)

2013-11-15

278

K?no kult?ros mokytojas kaip sveiko gyvenimo b?do pavyzdys  

OpenAIRE

Vaik? ir jaunuoli? sveikatos ugdymo vyksme labai reikšmingas vaidmuo tenka k?no kult?ros mokytojui. Jis turi ne vien tik mokyti fizini? pratim?, bet ir b?ti jaunimui vadovas ? mažai paž?stam? socialini? ir moralini? norm?, susijusi? su k?no kult?ra, pasaul?. Greta to, remdamasis išsamiomis žmogaus organizmo biologijos, fiziologijos žiniomis, jis turi siekti humanizuoti aukl?jimo ir švietimo vyksm?. Šio tyrimo tikslas buvo atsakyti ? tokius klausimus: Ar gali mokyto...

Nawarecki, Dariusz; Jagusz, Marek

2006-01-01

279

Dynamic Modeling of Anode Function in Enzyme-Based Biofuel Cells Using High Mediator Concentration  

Directory of Open Access Journals (Sweden)

Full Text Available The working principle of enzyme-based biofuel cells (EBFCs is the same as that of conventional fuel cells. In an EBFC system, the electricity-production process is very intricate. Analysis requires a mathematical model that can adequately describe the EBFC and predict its performance. This paper develops a dynamic model simulating the discharge performance of the anode for which supported glucose oxidase and mediator immobilize in the EBFC. The dynamic transport behavior of substrate, redox state (ROS of enzyme, enzyme-substrate complex, and the mediator creates different potential changes inside the anode. The potential-step method illustrates the dynamic phenomena of substrate diffusion, ROS of enzyme, production of enzyme-substrate complex, and reduction of the mediator with different potential changes.

Der-Sheng Chan

2012-07-01

280

Light regulation of cGMP metabolism in toad rod outer segments (ROS) deduced from intact photoreceptor and cellfree kinetics  

International Nuclear Information System (INIS)

The rate of cGMP hydrolysis by phosphodiesterase (PDE) in intact ROS, monitored in dark-adapted isolated toad retina by the rate of 18O appearance in guanine nucleotide ?-phosphoryls, is 1/360th of that observed in disrupted ROS at a substrate concentration equivalent to the total [cGMP] in ROS. Low to moderate photic stimuli increase this cGMP hydrolytic rate up to 10-fold in intact ROS with little or no change in total [cGMP]. G-protein activation determined in intact ROS by the fraction of GDP labeled with 18O corresponds with light-related increases in cGMP flux. In contrast, relatively high intensities and extended illumination cause attenuation of maximal cGMP hydrolysis with proportionate reductions in total [cGMP]. From these observations combined with the effects of activated G-protein on kinetics and cGMP binding of ROS PDE the following model for light-regulation of cGMP metabolism was deduced: cGMP flux in intact ROS is severely restricted in the dark state because approximately 99% of the cGMP is bound to high affinity sites on the non-stimulated form of PDE. This constraint is relieved when activated G-protein converts the cGMP-binding form of PDE to a high K/sub m/ catalytic form. cGMP is then redistributed to a dynamic pool where it is available to PDE catalytic sites and lower affinity allosteric sites. The [cGMP] in the dynamic pool is maintained or further increased or decreased by modulating the activity of an apparently lighlating the activity of an apparently light-sensitive guanylyl cyclase

281

Oxidative stress-mediated effects of angiotensin II in the cardiovascular system  

Science.gov (United States)

Angiotensin II (Ang II), an endogenous peptide hormone, plays critical roles in the pathophysiological modulation of cardiovascular functions. Ang II is the principle effector of the renin-angiotensin system for maintaining homeostasis in the cardiovascular system, as well as a potent stimulator of NAD(P)H oxidase, which is the major source and primary trigger for reactive oxygen species (ROS) generation in various tissues. Recent accumulating evidence has demonstrated the importance of oxidative stress in Ang II-induced heart diseases. Here, we review the recent progress in the study on oxidative stress-mediated effects of Ang II in the cardiovascular system. In particular, the involvement of Ang II-induced ROS generation in arrhythmias, cell death/heart failure, ischemia/reperfusion injury, cardiac hypertrophy and hypertension are discussed. Ca2+/calmodulin-dependent protein kinase II is an important molecule linking Ang II, ROS and cardiovascular pathological conditions. PMID:24587981

Wen, Hairuo; Gwathmey, Judith K; Xie, Lai-Hua

2014-01-01

282

Mitochondria-Derived Reactive Intermediate Species Mediate Asbestos-Induced Genotoxicity and Oxidative Stress–Responsive Signaling Pathways  

OpenAIRE

Background: The incidence of asbestos-induced human cancers is increasing worldwide, and considerable evidence suggests that reactive oxygen species (ROS) are important mediators of these diseases. Our previous studies suggested that mitochondria might be involved in the initiation of oxidative stress in asbestos-exposed mammalian cells.

Huang, Sarah X. L.; Partridge, Michael A.; Ghandhi, Shanaz A.; Davidson, Mercy M.; Amundson, Sally A.; Hei, Tom K.

2012-01-01

283

MST1 activation by curcumin mediates JNK activation, Foxo3a nuclear translocation and apoptosis in melanoma cells  

International Nuclear Information System (INIS)

Highlights: •Curcumin activates MST1 in melanoma cells. •MST1 mediates curcumin-induced apoptosis of melanoma cells. •ROS production is involved in curcumin-induced MST1 activation. •MST1 mediates curcumin-induced JNK activation in melanoma cells. •MST1 mediates curcumin-induced Foxo3a nuclear translocation and Bim expression. -- Abstract: Different groups including ours have shown that curcumin induces melanoma cell apoptosis, here we focused the role of mammalian Sterile 20-like kinase 1 (MST1) in it. We observed that curcumin activated MST1-dependent apoptosis in cultured melanoma cells. MST1 silencing by RNA interference (RNAi) suppressed curcumin-induced cell apoptosis, while MST1 over-expressing increased curcumin sensitivity. Meanwhile, curcumin induced reactive oxygen species (ROS) production in melanoma cells, and the ROS scavenger, N-acetyl-cysteine (NAC), almost blocked MST1 activation to suggest that ROS might be required for MST1 activation by curcumin. c-Jun N-terminal protein kinase (JNK) activation by curcumin was dependent on MST1, since MST1 inhibition by RNAi or NAC largely inhibited curcumin-induced JNK activation. Further, curcumin induced Foxo3 nuclear translocation and Bim-1 (Foxo3 target gene) expression in melanoma cells, such an effect by curcumin was inhibited by MST1 RNAi. In conclusion, we suggested that MST1 activation by curcumin mediates JNK activation, Foxo3a nuclear translocation and apoptosis in melanoma cells

284

MST1 activation by curcumin mediates JNK activation, Foxo3a nuclear translocation and apoptosis in melanoma cells  

Energy Technology Data Exchange (ETDEWEB)

Highlights: •Curcumin activates MST1 in melanoma cells. •MST1 mediates curcumin-induced apoptosis of melanoma cells. •ROS production is involved in curcumin-induced MST1 activation. •MST1 mediates curcumin-induced JNK activation in melanoma cells. •MST1 mediates curcumin-induced Foxo3a nuclear translocation and Bim expression. -- Abstract: Different groups including ours have shown that curcumin induces melanoma cell apoptosis, here we focused the role of mammalian Sterile 20-like kinase 1 (MST1) in it. We observed that curcumin activated MST1-dependent apoptosis in cultured melanoma cells. MST1 silencing by RNA interference (RNAi) suppressed curcumin-induced cell apoptosis, while MST1 over-expressing increased curcumin sensitivity. Meanwhile, curcumin induced reactive oxygen species (ROS) production in melanoma cells, and the ROS scavenger, N-acetyl-cysteine (NAC), almost blocked MST1 activation to suggest that ROS might be required for MST1 activation by curcumin. c-Jun N-terminal protein kinase (JNK) activation by curcumin was dependent on MST1, since MST1 inhibition by RNAi or NAC largely inhibited curcumin-induced JNK activation. Further, curcumin induced Foxo3 nuclear translocation and Bim-1 (Foxo3 target gene) expression in melanoma cells, such an effect by curcumin was inhibited by MST1 RNAi. In conclusion, we suggested that MST1 activation by curcumin mediates JNK activation, Foxo3a nuclear translocation and apoptosis in melanoma cells.

Yu, Teng, E-mail: tengyu33@yahoo.com [Department of Dermatology, Shandong Ji-ning No. 1 People’s Hospital, Shandong Province 272011 (China); Ji, Jiang [Department of Dermatology, The Second Hospital Affiliated of Soochow University, SuZhou, Jiangsu Province 215000 (China); Guo, Yong-li [Department of Oncology, Shandong Ji-ning No. 1 People’s Hospital, Shandong Province 272011 (China)

2013-11-08

285

Weightlessness influences the cytoskeleton and ROS level in SH-SY5Y neuroblastoma cells  

Science.gov (United States)

During Spaceflight the nerve system of astronauts was obviously influenced To investigate how gravity effects nerve system the SH-SY5Y neuroblastoma cells were taken as research object By utilizing clinostat and parabolic flight for the model of gravity changing the level of reactive oxygen species was assayed in different time under simulated microgravity the cytomorphology and cytoskeleton of SH-SY5Y neuroblastoma cells were also observed after parabolic flight and clinostat by the conventional and the confocal laser scanning microscope The data showed that ROS level was enhanced and the cytoskeleton was damaged which microfilaments and microtubules were highly disorganized the cell shape was deteriorated under simulated microgravity indicating the relativity between the ROS level fluctuating and cytoskeleton changing It illuminates signal transduction disturbed by oxidative stress also regulates the cytoskeleton changing in SH-SY5Y cells The results suggest the cytoskeleton which is the receptor for sensing gravity was also regulated by cellular redox state which clues on the complexity of cell for self-adjusting to gravity changing

Bo, Wang; Lina, Qu; Yingxian, Li; Qi, Li; Lei, Bi; Yinghui, Li

286

NADH: flavin oxidoreductase/NADH oxidase and ROS regulate microsclerotium development in Nomuraea rileyi.  

Science.gov (United States)

Based on transcriptome library, an NADH: flavinoxidore ductase/NADH oxidase gene (Nox) was cloned from Nomuraea rileyi. The 1,663-bp full-length cDNA contains an open reading frame of 1,233 bp coding 410 amino acids. The expression level of Nox was up-regulated and co-related to the intracellular H2O2 concentration during microsclerotium (MS) initiation. Rotenone inhibition showed that inhibition of Nox could cause a noticeable decrease in the MS yields. Silencing of Nox resulted in the MS yields, H2O2 and virulence decreased by 98.5, 38 and 21.5%, respectively. On the other hand, MS yields increased by 24.8-61% when induced by H2O2 or menadione. Furthermore, the reactive oxygen species (ROS) scavenger, ascorbic acid (up to 0.03 g ascorbic acid l(-1)), completely inhibited the formation of MS. In conclusion, the results obtained suggested that ROS promoted MS development, and that Nox was required for MS differentiation through regulation of intracellular H2O2 concentration. Besides, Nox had a great impact on the virulence in N. rileyi. PMID:24497186

Liu, Juanjuan; Yin, Youping; Song, Zhangyong; Li, Yan; Jiang, Shasha; Shao, Changwen; Wang, Zhongkang

2014-07-01

287

Decreasing GSH and increasing ROS in chemosensitivity gliomas with IDH1 mutation.  

Science.gov (United States)

Gliomas are the most malignant and aggressive primary brain tumor in adults. Despite concerted efforts to improve therapies, their prognosis remains very poor. Isocitrate dehydrogenase 1 (IDH1) mutations have been discovered frequently in glioma patients and are strongly correlated with improved survival. However, the effect of IDH1 mutations on the chemosensitivity of gliomas remains unclear. In this study, we generated clonal U87 and U251 glioma cell lines overexpressing the R132H mutant protein (IDH1-R132H). Compared with control cells and cells overexpressing IDH wild type (IDH1-WT), both types of IDH1-R132H cells were more sensitive to temozolomide (TMZ) and cis-diamminedichloroplatinum (CDDP) in a time- and dose-dependent manner. The IDH1-R132H-induced higher chemosensitivity was associated with nicotine adenine disphosphonucleotide (NADPH), glutathione (GSH) depletion, and reactive oxygen species (ROS) generation. Accordingly, this IDH1-R132H-induced growth inhibition was effectively abrogated by GSH in vitro and in vivo. Our study provides direct evidence that the improved survival in patients with IDH1-R132H tumors may partly result from the effects of the IDH1-R132H protein on chemosensitivity. The primary cellular events associated with improved survival are the GSH depletion and increased ROS generation. PMID:25283382

Shi, Jinlong; Sun, Baolan; Shi, Wei; Zuo, Hao; Cui, Daming; Ni, Lanchun; Chen, Jian

2015-02-01

288

ESR detection of ROS generated by TiO2 coated with fluoridated apatite.  

Science.gov (United States)

Specific materials used in the manufacture of dentures may enhance the removal of micro-organisms. The ultraviolet A (UVA) irradiation of acrylic resin containing titanium dioxide (TiO(2)) generates reactive oxygen species (ROS) by photocatalysis that shows antibacterial effects. In this study, we tested the hypothesis that TiO(2) coated with fluoridated apatite (FAp-TiO(2)) can generate ROS via photo-catalysis by using electron spin resonance (ESR), and that acrylic resin containing FAp-TiO(2) can show antifungal properties by measuring the viability of Candida albicans. We demonstrated that hydroxyl radicals (HO(*)) were generated through excitation of TiO(2), TiO(2) coated with apatite (HAp-TiO(2)), and FAp-TiO(2). The HO(*) generation through excitation of FAp-TiO(2) was higher than that of TiO(2) and HAp-TiO(2). Regarding antifungal activity, cell viability on acrylic resin containing FAp-TiO(2) was lower than that of TiO(2) and HAp-TiO(2). FAp-TiO(2) showed superior photocatalytic effects, and these characteristics may lead to novel methods for the clinical application of denture-cleaning treatments. PMID:20525961

Sawada, Tomofumi; Yoshino, F; Kimoto, K; Takahashi, Y; Shibata, T; Hamada, N; Sawada, Tomoji; Toyoda, M; Lee, M-C

2010-08-01

289

Rod and cone photoreceptor cells produce ROS in response to stress in a live retinal explant system.  

LENUS (Irish Health Repository)

PURPOSE: The production of reactive oxygen species (ROS) can lead to oxidative stress, which is a strong contributory factor to many ocular diseases. In this study, the removal of trophic factors is used as a model system to investigate the effects of stress in the retina. The aims were to determine if both rod and cone photoreceptor cells produce ROS when they are deprived of trophic factor support and to demonstrate if the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (Nox) enzymes are responsible for this ROS production. METHODS: Retinas were explanted from mice aged between postnatal days 8-10 and cultured overnight. The following morning, confocal microscopy combined with various fluorescent probes was used to detect the production of ROS. Each time peanut agglutinin (PNA), a cone photoreceptor marker, was used to facilitate orientation of the retina. Dihydroethidium and dihydrorhodamine 123 (DHR123) were used to determine which cells produce ROS. Subsequently, western blots of retinal serial sections were used to detect the presence of Noxs in the different retinal layers. The Nox inhibitor apocynin was then tested to determine if it altered the production of ROS within these cells. RESULTS: Live retinal explants, viewed at high magnifications using confocal microscopy, displayed an increase in the fluorescent products of dihydroethidium and DHR123 upon serum removal when compared to controls. DHR123 fluorescence, once oxidized, localized to mitochondria and was found in the same focal plane as the PNA staining. This showed that cones and rods produced ROS when stressed. Retinal serial sectioning established that the photoreceptor layer expressed Nox4, dual oxidase (Duox) 1, and Duox2 at varying levels. Finally, the Nox inhibitor apocynin decreased the burst stimulated by the stress of serum removal. CONCLUSIONS: Confocal microscopy and PNA staining allowed differentiation of cell types within the outermost layers of the retina, demonstrating that both rods and cones generated ROS in response to the stress of serum deprivation. Nox4 was the most abundantly expressed Nox in the photoreceptor layer, but Duox1 and Duox2 were also present at detectable levels, and as apocynin reduced the levels of ROS produced, this implied that these proteins may play some role in this production.

Bhatt, Lavinia

2010-01-01

290

Single-cell analysis of dihydroartemisinin-induced apoptosis through reactive oxygen species-mediated caspase-8 activation and mitochondrial pathway in ASTC-a-1 cells using fluorescence imaging techniques  

Science.gov (United States)

Dihydroartemisinin (DHA), a front-line antimalarial herbal compound, has been shown to possess promising anticancer activity with low toxicity. We have previously reported that DHA induced caspase-3-dependent apoptosis in human lung adenocarcinoma cells. However, the cellular target and molecular mechanism of DHA-induced apoptosis is still poorly defined. We use confocal fluorescence microscopy imaging, fluorescence resonance energy transfer, and fluorescence recovery after photobleaching techniques to explore the roles of DHA-elicited reactive oxygen species (ROS) in the DHA-induced Bcl-2 family proteins activation, mitochondrial dysfunction, caspase cascade, and cell death. Cell Counting Kit-8 assay and flow cytometry analysis showed that DHA induced ROS-mediated apoptosis. Confocal imaging analysis in a single living cell and Western blot assay showed that DHA triggered ROS-dependent Bax translocation, mitochondrial membrane depolarization, alteration of mitochondrial morphology, cytochrome c release, caspase-9, caspase-8, and caspase-3 activation, indicating the coexistence of ROS-mediated mitochondrial and death receptor pathway. Collectively, our findings demonstrate for the first time that DHA induces cell apoptosis by triggering ROS-mediated caspase-8/Bid activation and the mitochondrial pathway, which provides some novel insights into the application of DHA as a potential anticancer drug and a new therapeutic strategy by targeting ROS signaling in lung adenocarcinoma therapy in the future.

Lu, Ying-Ying; Chen, Tong-Sheng; Wang, Xiao-Ping; Li, Li

2010-07-01

291

Oxidation-extraction spectrometry of reactive oxygen species (ROS) generated by chlorophyllin magnesium (Chl-Mg) under ultrasonic irradiation.  

Science.gov (United States)

In order to examine the mechanism and process of sonodynamic reaction, the chlorophyllin magnesium (Chl-Mg) acting as a sonosensitizer was irradiated by ultrasound, and the generation of reactive oxygen species (ROS) were detected by the method of oxidation-extraction spectrometry (OES). That is, under ultrasonic irradiation in the presence of Chl-Mg, the 1,5-diphenyl carbazide (DPCI) is oxidized by generated ROS into 1,5-diphenyl carbazone (DPCO), which can be extracted by mixed organic solvent and display a obvious visible absorption at 563 nm wavelength. Besides, the generation conditions of ROS were also reviewed. The results demonstrated that the quantities of generated ROS increased with the increase of ultrasonic irradiation time, Chl-Mg concentration and DPCI concentration. Finally, several radical scavengers (l-Histidine (His), 2,6-Di-tert-butyl-methylphenol (BHT) and Vitamin C (VC)) were used to determine the kind of the generated ROS. It was found that at least the hydroxyl radical (OH) and singlet oxygen (1O2) were generated in the presence of Chl-Mg under ultrasonic irradiation. It is wish that this paper might offer some valuable references for the study on the mechanism of SDT and the application of Chl-Mg in tumor treatment. PMID:21620761

Guo, Yuwei; Cheng, Chunping; Wang, Jun; Jin, Xudong; Liu, Bin; Wang, Zhiqiu; Gao, Jingqun; Kang, Pingli

2011-09-01

292

Podophyllotoxin acetate enhances ?-ionizing radiation-induced apoptotic cell death by stimulating the ROS/p38/caspase pathway.  

Science.gov (United States)

To develop a new radiosensitizer against non-small cell lung cancer cells, we screened a natural product library for growth-inhibitory compounds. PA was found to be cytotoxic toward NCI-H460 cells, and its IC50 value was determined. The radiosensitizer effects of PA were tested at its IC50 value in clonogenic and cell-counting assays. The intracellular mechanism underlying this effect was determined by immunoblotting and by measuring propidium iodide uptake and ROS generation. The radiosensitizer activity of PA in vivo was tested in nude mice by treating with PA and IR, and measuring tumor volume and assessing apoptosis. PA, tested at its experimentally determined IC50 value (12nM), enhanced IR-induced death of NCI-H460 cells by increasing apoptosis, yielding a mean calculated dose-enhancement ratio of 1.67. Combination with PA and IR also increased the production of ROS, which subsequently induced phosphorylation of p38, suppressed phosphorylation of ERK, and activated caspase-3, -8, and -9. Notably, inhibition of ROS production prevented p38 phosphorylation, and inhibition of ROS production or p38 activation blocked caspase activation and apoptosis. In a xenograft assay, combination with PA and IR delayed tumor growth by 11.4days compared with controls, yielding an enhancement factor of 1.48. Collectively, these results indicate that PA functions as a radiosensitizer by enhancing apoptosis through activation of a ROS/p38/caspase pathway and suppression of ERK. PMID:25776488

Choi, Jae Yeon; Cho, Hyun-Ji; Hwang, Sang-Gu; Kim, Wun-Jae; Kim, Jong-Il; Um, Hong-Duck; Park, Jong Kuk

2015-03-01

293

Reactive oxygen species (ROS) production in human peripheral blood neutrophils exposed in vitro to static magnetic field.  

Science.gov (United States)

The aim of this study was to determine the effect of gradient static magnetic field (SMF) on reactive oxygen species (ROS) production in human neutrophils in peripheral blood in vitro. Blood samples collected from healthy individuals were incubated in an inhomogeneous SMF (in a south or north pole of the field) for 15, 30 or 45 minutes. The maximum value of induction (B max) amounted to ? 60 mT. To determine the strength of the ROS production, dihydrorhodamine (123DHR) as fluorophore and phorbol 12-myristate 13-acetate (PMA) as respiratory burst stimulator were used. 123DHR oxidation by ROS was measured by flow cytometry. The exposure of blood samples to SMF induced statistically significant changes in ROS production in unstimulated and PMA-stimulated neutrophils. The observed effects were highly correlated with the exposure time and depended on the orientation of the field. Although intracellular mechanisms underlying such interactions are not thoroughly understood, it could be presumed that SMF affects ROS metabolic oscillations and their formation and inactivation. This study emphasizes the importance of proper adjustment of exposure time to SMF for any potential therapeutic applications. PMID:23631724

Poniedzia?ek, Barbara; Rzymski, Piotr; Karczewski, Jacek; Jaroszyk, Feliks; Wiktorowicz, Krzysztof

2013-12-01

294

Axion mediation  

Science.gov (United States)

We explore the possibility that supersymmetry breaking is mediated to the Standard Model sector through the interactions of a generalized axion multiplet that gains a F-term expectation value. Using an effective field theory framework we enumerate the most general possible set of axion couplings and compute the Standard Model sector soft-supersymmetry-breaking terms. Unusual, non-minimal spectra, such as those of both natural and split supersymmetry are easily implemented. We discuss example models and low-energy spectra, as well as implications of the particularly minimal case of mediation via the QCD axion multiplet. We argue that if the Peccei-Quinn solution to the strong-CP problem is realized in string theory then such axion-mediation is generic, while in a field theory model it is a natural possibility in both DFSZ- and KSVZ-like regimes. Axion mediation can parametrically dominate gravity-mediation and is also cosmologically beneficial as the constraints arising from axino and gravitino overproduction are reduced. Finally, in the string context, axion mediation provides a motivated mechanism where the UV completion naturally ameliorates the supersymmetric flavor problem.

Baryakhtar, Masha; Hardy, Edward; March-Russell, John

2013-07-01

295

Perspectives on mitochondrial uncoupling proteins-mediated neuroprotection.  

Science.gov (United States)

The integrity of mitochondrial function is essential to cell life. It follows that disturbances of mitochondrial function will lead to disruption of cell function, expressed as disease or even death. Considering that neuronal uncoupling proteins (UCPs) decrease reactive oxygen species (ROS) production at the expense of energy production, it is important to understand the underlying mechanisms by which UCPs control the balance between the production of adenosine triphosphate (ATP) and ROS in the context of normal physiological activity and in pathological conditions. Here we review the current understanding of neuronal UCPs-mediated respiratory uncoupling process by performing a survey in their physiology and regulation. The latest findings regarding neuronal UCPs physiological roles and their involvement and interest as potential targets for therapeutic intervention in brain diseases will also be exploited. PMID:25217852

Cardoso, Susana; Correia, Sónia; Carvalho, Cristina; Candeias, Emanuel; Plácido, Ana I; Duarte, Ana I; Seiça, Raquel M; Moreira, Paula I

2015-04-01

296

Vorinostat and sorafenib increase CD95 activation in gastrointestinal tumor cells through a Ca2+ - de novo ceramide - PP2A - ROS dependent signaling pathway  

OpenAIRE

The targeted therapeutics sorafenib and vorinostat interact in a synergistic fashion to kill carcinoma cells by activating CD95, and this drug combination is entering phase I evaluation. In this study we determined how CD95 is activated by treatment with this drug combination. Low doses of sorafenib and vorinostat but not the individual drugs rapidly increased ROS, Ca2+ and ceramide levels in GI tumor cells. The production of ROS was reduced in Rho zero cells. Quenching ROS blocked drug-induc...

Park, Margaret A.; Mitchell, Clint; Zhang, Guo; Yacoub, Adly; Allegood, Jeremy; Ha?ussinger, Dieter; Reinehr, Roland; Larner, Andrew; Spiegel, Sarah; Fisher, Paul B.; Voelkel-johnson, Christina; Ogretmen, Besim; Grant, Steven; Dent, Paul

2010-01-01

297

Inclusion complexes of chloramphenicol with ?-cyclodextrin and aminoacids as a way to increase drug solubility and modulate ROS production.  

Science.gov (United States)

The aim of this study was to improve the solubility of chloramphenicol and reduce the production of reactive oxygen species (ROS) in leucocytes induced by this drug, using complexation. Multicomponent complexes were prepared by the addition of ?-cyclodextrin with glycine or cysteine. Nuclear magnetic resonance and phase solubility studies provided information at the molecular level on the structure of the complexes and their association binding constants, respectively. In the solid state, all systems were extensively characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, thermal analysis and X-ray powder diffraction. Antimicrobial activity of inclusion complexes was investigated by agar diffusion methods. Finally ROS determination by chemiluminescence was used to investigate the effect of complex formation on the potential toxicity in human leucocytes. These studies revealed that multicomponent complexes can increase the aqueous solubility of chloramphenicol as well as reducing the stress by ROS production in leucocytes and maintaining its microbiological activity. PMID:25659705

Aiassa, Virginia; Zoppi, Ariana; Albesa, Inés; Longhi, Marcela R

2015-05-01

298

Control of reactive oxygen species (ROS) production through histidine kinases in Aspergillus nidulans under different growth conditions.  

Science.gov (United States)

Sensor histidine kinases (HKs) are important factors that control cellular growth in response to environmental conditions. The expression of 15 HKs from Aspergillus nidulans was analyzed by quantitative real-time PCR under vegetative, asexual, and sexual growth conditions. Most HKs were highly expressed during asexual growth. All HK gene-disrupted strains produced reactive oxygen species (ROS). Three HKs are involved in the control of ROS: HysA was the most abundant under the restricted oxygen condition, NikA is involved in fungicide sensing, and FphA inhibits sexual development in response to red light. Phosphotransfer signal transduction via HysA is essential for ROS production control. PMID:24490133

Hayashi, Saki; Yoshioka, Megumi; Matsui, Tetsuji; Kojima, Kensuke; Kato, Masashi; Kanamaru, Kyoko; Kobayashi, Tetsuo

2014-01-01

299

Control of reactive oxygen species (ROS) production through histidine kinases in Aspergillus nidulans under different growth conditions?  

Science.gov (United States)

Sensor histidine kinases (HKs) are important factors that control cellular growth in response to environmental conditions. The expression of 15 HKs from Aspergillus nidulans was analyzed by quantitative real-time PCR under vegetative, asexual, and sexual growth conditions. Most HKs were highly expressed during asexual growth. All HK gene-disrupted strains produced reactive oxygen species (ROS). Three HKs are involved in the control of ROS: HysA was the most abundant under the restricted oxygen condition, NikA is involved in fungicide sensing, and FphA inhibits sexual development in response to red light. Phosphotransfer signal transduction via HysA is essential for ROS production control. PMID:24490133

Hayashi, Saki; Yoshioka, Megumi; Matsui, Tetsuji; Kojima, Kensuke; Kato, Masashi; Kanamaru, Kyoko; Kobayashi, Tetsuo

2014-01-01

300

Apoptosis induction by silica nanoparticles mediated through reactive oxygen species in human liver cell line HepG2  

International Nuclear Information System (INIS)

Silica nanoparticles are increasingly utilized in various applications including agriculture and medicine. In vivo studies have shown that liver is one of the primary target organ of silica nanoparticles. However, possible mechanisms of hepatotoxicity caused by silica nanoparticles still remain unclear. In this study, we explored the reactive oxygen species (ROS) mediated apoptosis induced by well-characterized 14 nm silica nanoparticles in human liver cell line HepG2. Silica nanoparticles (25–200 ?g/ml) induced a dose-dependent cytotoxicity in HepG2 cells. Silica nanoparticles were also found to induce oxidative stress in dose-dependent manner indicated by induction of ROS and lipid peroxidation and depletion of glutathione (GSH). Quantitative real-time PCR and immunoblotting results showed that both the mRNA and protein expressions of cell cycle checkpoint gene p53 and apoptotic genes (bax and caspase-3) were up-regulated while the anti-apoptotic gene bcl-2 was down-regulated in silica nanoparticles treated cells. Moreover, co-treatment of ROS scavenger vitamin C significantly attenuated the modulation of apoptotic markers along with the preservation of cell viability caused by silica nanoparticles. Our data demonstrated that silica nanoparticles induced apoptosis in human liver cells, which is ROS mediated and regulated through p53, bax/bcl-2 and caspase pathways. This study suggests that toxicity mechanisms of silica nanoparticles should be further investigated at in vivo level. -- Highlights: ? We explored the mechanisms of toxicity caused by silica NPs in human liver HepG2 cells. ? Silica NPs induced a dose-dependent cytotoxicity in HepG2 cells. ? Silica NPs induced ROS generation and oxidative stress in a dose-dependent manner. ? Silica NPs were also modulated apoptosis markers both at mRNA and protein levels. ? ROS mediated apoptosis induced by silica NPs was preserved by vitamin C.

301

Surface topography of hydroxyapatite affects ROS17/2.8 cells response A topografia de superfície da hidroxiapatita afeta a resposta de células ROS17/2.8  

Directory of Open Access Journals (Sweden)

Full Text Available Hydroxyapatite (HA has been used in orthopedic, dental, and maxillofacial surgery as a bone substitute. The aim of this investigation was to study the effect of surface topography produced by the presence of microporosity on cell response, evaluating: cell attachment, cell morphology, cell proliferation, total protein content, and alkaline phosphatase (ALP activity. HA discs with different percentages of microporosity (A hidroxiapatita (HA tem sido utilizada como revestimento de implantes e para substituição de tecido ósseo. O objetivo deste estudo foi avaliar o efeito da topografia de superfície da HA, resultante da presença de microporosidade, sobre a adesão, a morfologia e proliferação celulares, a medida de proteína total e a atividade de fosfatase alcalina. Discos de HA com diferentes porcentagens de microporosidade (< 5%, 15% e 30% foram fabricados por uma combinação das técnicas de pressão uniaxial e sinterização. Células ROS17/2.8 foram cultivadas sobre os discos de HA. Para a adesão, as células foram cultivadas por duas horas. A morfologia foi avaliada após sete dias. A proliferação, medida de proteína total e atividade de ALP foram avaliadas após sete e quatorze dias. Os dados foram comparados por ANOVA e teste de Duncan quando apropriado. A adesão (p = 0,11 e a medida de proteína total (p = 0,31 não foram afetadas pela topografia de superfície. A proliferação após sete e quatorze dias (p = 0,0007 e p = 0,003, respectivamente, e a atividade de ALP (p = 0,0007 foram significantemente menores na superfície irregular (HA30. Esses resultados sugerem que eventos iniciais não são afetados pela topografia, enquanto superfícies com topografias mais regulares (microporosidade de 15% ou menos favoreceram eventos intermediários e finais, como proliferação e atividade de ALP.

Adalberto Luiz Rosa

2002-09-01

302

Particulate matter air pollution disrupts endothelial cell barrier via calpain-mediated tight junction protein degradation  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Exposure to particulate matter (PM is a significant risk factor for increased cardiopulmonary morbidity and mortality. The mechanism of PM-mediated pathophysiology remains unknown. However, PM is proinflammatory to the endothelium and increases vascular permeability in vitro and in vivo via ROS generation. Objectives We explored the role of tight junction proteins as targets for PM-induced loss of lung endothelial cell (EC barrier integrity and enhanced cardiopulmonary dysfunction. Methods Changes in human lung EC monolayer permeability were assessed by Transendothelial Electrical Resistance (TER in response to PM challenge (collected from Ft. McHenry Tunnel, Baltimore, MD, particle size >0.1??m. Biochemical assessment of ROS generation and Ca2+ mobilization were also measured. Results PM exposure induced tight junction protein Zona occludens-1 (ZO-1 relocation from the cell periphery, which was accompanied by significant reductions in ZO-1 protein levels but not in adherens junction proteins (VE-cadherin and ?-catenin. N-acetyl-cysteine (NAC, 5?mM reduced PM-induced ROS generation in ECs, which further prevented TER decreases and atteneuated ZO-1 degradation. PM also mediated intracellular calcium mobilization via the transient receptor potential cation channel M2 (TRPM2, in a ROS-dependent manner with subsequent activation of the Ca2+-dependent protease calpain. PM-activated calpain is responsible for ZO-1 degradation and EC barrier disruption. Overexpression of ZO-1 attenuated PM-induced endothelial barrier disruption and vascular hyperpermeability in vivo and in vitro. Conclusions These results demonstrate that PM induces marked increases in vascular permeability via ROS-mediated calcium leakage via activated TRPM2, and via ZO-1 degradation by activated calpain. These findings support a novel mechanism for PM-induced lung damage and adverse cardiovascular outcomes.

Wang Ting

2012-08-01

303

NOX4 activity is determined by mRNA levels and reveals a unique pattern of ROS generation  

OpenAIRE

Abstract NOX4 is an enigmatic member of the NOX family of ROS-generating NADPH oxidases. NOX4 has a wide tissue distribution, but the physiological function and activation mechanisms are largely unknown, and its pharmacology poorly understood. We have generated cell lines expressing NOX4 upon tetracycline induction. Tetracycline induced a rapid increase in NOX4 mRNA (1h) followed closely (2h) by a release of reactive oxygen species (ROS). Upon tetracycline withdrawal, NOX4 mRNA lev...

Serrander, Lena; Cartier, Laetitia; Bedard, Karen; Banfi, Botond; Lardy, Bernard; Plastre, Olivier; Sienkiewicz, Andrzej; Fo?rro?, Laszlo?; Schlegel, Werner; Krause, Karl-heinz

2007-01-01

304

SkiROS: A four tiered architecture for task-level programming of industrial mobile manipulators  

DEFF Research Database (Denmark)

During the last decades, the methods for intuitive task level programming of robots have become a fundamental point of interest for industrial application. The paper in hand presents SkiROS (Skill-based Robot Operating System) a novel software architecture based on the skills paradigm. The skill paradigm has already been used and tested within the FP7 project TAPAS, and we are going to use it in several new FP7 projects (CARLOS, STAMINA, ACAT). It facilitates task-level programming of mobile manipulators by providing the robot with a set of movement primitives, skills and tasks. This hierarchy brings many advantages, where the most relevant is the separation of control in the layers of hardware abstraction(proxy), multi-sensory control(primitive), object-level abstraction (skill) and planning (task). The de?nition and the clear division in different abstraction levels allows the implementation of a ?exible, highly modular system for the development of cognitive robot tasks.

Rovida, Francesco; Chrysostomou, Dimitris

305

8-bromo-7-methoxychrysin-induced apoptosis of hepatocellular carcinoma cells involves ROS and JNK  

Directory of Open Access Journals (Sweden)

Full Text Available AIM: To investigate whether the apoptotic activities of 8-bromo-7-methoxychrysin (BrMC involve reactive oxygen species (ROS generation and c-Jun N-terminal kinase (JNK activation in human hepatocellular carcinoma cells (HCC.METHODS: HepG2, Bel-7402 and L-02 cell lines were cultured in vitro and the apoptotic effects of BrMC were evaluated by flow cytometry (FCM after propidium iodide (PI staining, caspase-3 activity using enzyme-linked immunosorbent assay (ELISA, and DNA agarose gel electrophoresis. ROS production was evaluated by FCM after dichlorodihydrofluorescein diacetate (DCHF-DA probe labeling. The phosphorylation level of JNK and c-Jun protein was analyzed by Western blotting.RESULTS: FCM after PI staining showed a dose-dependent increase in the percentage of the sub-G1 cell population (P < 0.05, reaching 39.0% ± 2.8% of HepG2 cells after 48 h of treatment with BrMC at 10 ?mol/L. The potency of BrMC to HepG2 and Bel-7402 (32.1% ± 2.6% cells was found to be more effective than the lead compound, chrysin (16.2% ± 1.6% for HepG2 cells and 11.0% ± 1.3% for Bel-7402 cell at 40 ?mol/L and similar to 5-flurouracil (33.0% ± 2.1% for HepG2 cells and 29.3% ± 2.3% for Bel-7402 cells at 10 ?mol/L. BrMC had little effect on human embryo liver L-02 cells, with the percentage of sub-G1 cell population 5.4% ± 1.8%. Treatment of HepG2 cells with BrMC for 48 h also increased the levels of active caspase-3, in a concentration-dependent manner. z-DEVD-fmk, a caspase-3-specific inhibitor, prevented the activation of caspase-3. Treatment with BrMC at 10 ?mol/L for 48 h resulted in the formation of a DNA ladder. Treatment of cells with BrMC (10 ?mol/L increased mean fluorescence intensity of DCHF-DA in HepG2 cells from 7.2 ± 1.12 at 0 h to 79.8 ± 3.9 at 3 h and 89.7 ± 4.7 at 6 h. BrMC did not affect ROS generation in L-02 cells. BrMC treatment failed to induce cell death and caspase-3 activation in HepG2 cells pretreated with N-acetylcysteine (10 mmol/L. In addition, in HepG2 cells treated with BrMC (2.5, 5.0, 10.0 ?mol/L for 12 h, JNK activation was observed. Peak JNK activation occurred at 12 h post-treatment and this activation persisted for up to 24 h. The expression of phosphorylated JNK and c-Jun protein after 12 h with BrMC-treated cells was inhibited by N-acetylcysteine and SP600125 pre-treatment, but GW9662 had no effect. SP600125 substantially reduced BrMC-induced cell death and caspase-3 activation of HepG2 cells. N-acetylcysteine and GW9662 also attenuated induction of cell death and caspase-3 activation in HepG2 cells treated with BrMC.CONCLUSION: BrMC induces apoptosis of HCC cells by ROS generation and sustained JNK activation.

Xiao-Hong Yang, Xing Zheng, Jian-Guo Cao, Hong-Lin Xiang, Fei Liu, Yuan Lv

2010-07-01

306

Sericins exhibit ROS-scavenging, anti-tyrosinase, anti-elastase, and in vitro immunomodulatory activities.  

Science.gov (United States)

Some biological properties of Bombyx mori sericins from twenty strains were investigated, fourteen fed with artificial diet, two with fresh mulberry leaves and four with both diets. Sericin exhibited ROS-scavenging, anti-tyrosinase and anti-elastase properties, the strain significantly influenced these properties, while diet only influenced the anti-tyrosinase activity. Sericins were clustered into 5 groups and one sericin from each group was further studied: sericins showed anti-proliferative activity on in vitro stimulated peripheral blood mononuclear cells; some strains decreased in vitro secretion of IFN?, while no effects were observed on TNF? and IL10 release. Therefore, a mixture of sericins extracted from the most promising strains may be useful for dermatological and cosmetic use. PMID:23541552

Chlapanidas, Theodora; Faragò, Silvio; Lucconi, Giulia; Perteghella, Sara; Galuzzi, Marta; Mantelli, Melissa; Avanzini, Maria Antonietta; Tosca, Marta Cecilia; Marazzi, Mario; Vigo, Daniele; Torre, Maria Luisa; Faustini, Massimo

2013-07-01

307

Divergence to apoptosis from ROS induced cell cycle arrest: Effect of cadmium  

Energy Technology Data Exchange (ETDEWEB)

Recently, the role of cadmium (Cd) in immunosupression has gained importance. Nevertheless, the signaling pathways underlying cadmium-induced immune cell death remains largely unclear. In accordance to our previous in vivo report, and to evaluate the further details of the mechanism, we have investigated the effects of cadmium (CdCl{sub 2}, H{sub 2}O) on cell cycle regulation and apoptosis in splenocytes in vitro. Our results have revealed that reactive oxygen species (ROS) and p21 are involved in cell cycle arrest in a p53 independent manner but late hour apoptotic response was accompanied by the p53 up-regulation, loss of mitochondrial transmembrane potential (MTP), down-regulation of Bcl-xl, activation of caspase-3 and release of cytochrome c (Cyt c). However, pifithrin alfa (PFT-{alpha}), an inhibitor of p53, fails to rescue the cells from the cadmium-induced cell cycle arrest but prevents Bcl-xl down-regulation and loss of {Delta}{psi}{sub m}, which indicates that there is an involvement of p53 in apoptosis. In contrast, treatment with N-acetyl cysteine (NAC) can prevent cell cycle arrest and p21 up-regulation at early hours. Although it is clear that, NAC has no effect on apoptosis, p53 expression and MPT changes at late stage events. Taken together, we have demonstrated that cadmium promotes ROS generation, which potently initiates the cell cycle arrest at early hours and finally induces p53-dependent apoptosis at later part of the event.

Chatterjee, Soumya; Kundu, Subhadip; Sengupta, Suman [Department of Environmental Science, University of Kalyani, West Bengal 741235 (India); Department of Zoology, University of Calcutta, Calcutta-700019, West Bengal (India); Bhattacharyya, Arindam, E-mail: arindam19@yahoo.com [Department of Environmental Science, University of Kalyani, West Bengal 741235 (India); Department of Zoology, University of Calcutta, Calcutta-700019, West Bengal (India)

2009-04-26

308

Probucol suppresses human glioma cell proliferation in vitro via ROS production and LKB1-AMPK activation  

Science.gov (United States)

Aim: Probucol, an anti-hyperlipidemic drug, has been reported to exert antitumor activities at various stages of tumor initiation, promotion and progression. In this study we examined whether the drug affected glioma cell growth in vitro and the underlying mechanisms. Methods: Human glioma U87 and glioblastoma SF295 cell lines were used. Cell proliferation was accessed using the cell proliferation assay and BrdU incorporation. The phosphorylation of AMPK, liver kinase B1 (LKB1) and p27Kip1 was detected by Western blot. The activity of 26S proteasome was assessed with an in situ fluorescent substrate. siRNAs were used to suppress the expression of the relevant signaling proteins. Results: Treatment of U87 glioma cells with probucol (10–100 ?mol/L) suppressed the cell proliferation in dose- and time dependent manners. Meanwhile, probucol markedly increased the ROS production, phosphorylation of AMPK at Thr172 and LKB1 at Ser428 in the cells. Furthermore, probucol significantly decreased 26S proteasome activity and increased p27Kip1 protein level in the cells in an AMPK-dependent manner. Probucol-induced suppression of U87 cell proliferation could be reversed by pretreatment with tempol (a superoxide dismutase mimetic), MG132 (proteasome inhibitor) or compound C (AMPK inhibitor), or by gene silencing of LKB1, AMPK or p27Kip1. Similar results were observed in probucol-treated SF295 cells. Conclusion: Probucol suppresses human glioma cell proliferation in vitro via ROS production and LKB1-AMPK activation, which reduces 26S proteasome-dependent degradation of p27Kip1. PMID:25399650

Jiang, Yong-sheng; Lei, Jing-an; Feng, Fang; Liang, Qi-ming; Wang, Fu-rong

2014-01-01

309

The histone acetyltransferase MOF overexpression blunts cardiac hypertrophy by targeting ROS in mice.  

Science.gov (United States)

Imbalance between histone acetylation/deacetylation critically participates in the expression of hypertrophic fetal genes and development of cardiac hypertrophy. While histone deacetylases play dual roles in hypertrophy, current evidence reveals that histone acetyltransferase such as p300 and PCAF act as pro-hypertrophic factors. However, it remains elusive whether some histone acetyltransferases can prevent the development of hypertrophy. Males absent on the first (MOF) is a histone acetyltransferase belonging to the MYST (MOZ, Ybf2/Sas3, Sas2 and TIP60) family. Here in this study, we reported that MOF expression was down-regulated in failing human hearts and hypertrophic murine hearts at protein and mRNA levels. To evaluate the roles of MOF in cardiac hypertrophy, we generated cardiac-specific MOF transgenic mice. MOF transgenic mice did not show any differences from their wide-type littermates at baseline. However, cardiac-specific MOF overexpression protected mice from transverse aortic constriction (TAC)-induced cardiac hypertrophy, with reduced radios of heart weight (HW)/body weight (BW), lung weight/BW and HW/tibia length, decreased left ventricular wall thickness and increased fractional shortening. We also observed lower expression of hypertrophic fetal genes in TAC-challenged MOF transgenic mice compared with that of wide-type mice. Mechanically, MOF overexpression increased the expression of Catalase and MnSOD, which blocked TAC-induced ROS and ROS downstream c-Raf-MEK-ERK pathway that promotes hypertrophy. Taken together, our findings identify a novel anti-hypertrophic role of MOF, and MOF is the first reported anti-hypertrophic histone acetyltransferase. PMID:24802406

Qiao, Weiwei; Zhang, Weili; Gai, Yusheng; Zhao, Lan; Fan, Juexin

2014-06-13

310

Photochemically induced formation of reactive oxygen species (ROS) from effluent organic matter.  

Science.gov (United States)

The formation of reactive oxygen species (ROS) from effluent organic matter (EfOM) was investigated under simulated solar irradiation. In this study, EfOM was isolated into three different fractions based on hydrophobicity. The productivity of ROS in EfOM was measured and compared with that of natural organic matter (NOM) isolates, including Suwannee River humic acid/fulvic acid (SRHA/FA) and Pony Lake fulvic acid (PLFA). The hydrophilic (HPI) component had a greater quantum yield of 1O2 than those of the hydrophobic (HPO) and transphilic (TPI) fractions because the HPI contained peptides and proteins. Regarding O2•-, the phenolic moieties acted as electron donating species after photochemical excitation and therefore electron transfer to oxygen. A positive correlation was found between the phenolic concentrations and the steady state O2•-concentrations. H2O2 accumulated during the irradiation process from superoxide as precursor. Potentially, due to the presence of proteins or other organic species in the HPI fraction, the decay rates of H2O2 in the dark for both the effluent wastewater and the HPI fraction were significantly faster than the rates observed in the standard NOM isolates, the HPO and TPI fractions. Autochthonous NOM showed a higher •OH productivity than terrestrial NOM. The [•OH]ss was lowest in the HPI fraction due to the lack of humic fraction and existence of soluble microbial products (SMPs), which easily reacted with •OH. Overall, the HPO and TPI fractions were the major sources of superoxide, H2O2 and •OH under simulated solar irradiation. The HPI fraction dominated the production of 1O2 and acted as a sink for H2O2 and •OH. PMID:25314220

Zhang, Danning; Yan, Shuwen; Song, Weihua

2014-11-01

311

Structure-activity relationship of trifluoromethyl-containing metallocenes: electrochemistry, lipophilicity, cytotoxicity, and ROS production.  

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We report the synthesis of trifluoromethylated metallocenes (M=Fe, Ru) and related metal-free compounds for comparison of their biological properties with the aim to establish structure-activity relationships toward the anti-proliferative activity of this compound class. All new compounds were comprehensively characterized by NMR spectroscopy ((1) H, (13) C, (19) F), mass spectrometry, IR spectroscopy, and elemental analysis. A single-crystal X-ray structure was obtained on the Ru derivative, 1-(1-hydroxy-1-hexafluoromethylethyl)ruthenocene (3). The cytotoxicity of all compounds was tested on MCF-7, HT-29, and PT-45 cells, and IC50 values as low as 12 ?M were observed. Both the metallocene moiety and the hydroxy function are crucial for cytotoxicity. In addition, the activity decreased sharply even if only one trifluoromethyl group was replaced with a methyl group. Electrochemical investigations by cyclic voltammetry revealed that all CF3 -containing compounds are harder to oxidize than the unsubstituted metallocenes. Moreover, log?P determination by RP-HPLC showed the fluorinated derivatives to have higher lipophilicity, with log?P values up to 4.6. At the same time, the generation of reactive oxygen species (ROS) in Jurkat cells by these compounds was investigated by flow cytometry. Strong ROS production was shown exclusively for the bis-CF3 derivative 1-(1-hydroxy-1-hexafluoromethylethyl)ferrocene (1) after 6 and 24 h. Also on the Jurkat cell line, only compound 1 strongly induces necrosis after 24 and 48 h, as shown by annexin V/propidium iodide staining. No induction of apoptosis was observed. We propose that compound 1 is more efficiently incorporated into cancer cells relative to all other derivatives, causing significant induction of oxidative stress within the cell, which ultimately leads to cell death. PMID:24838930

Maschke, Marcus; Alborzinia, Hamed; Lieb, Max; Wölfl, Stefan; Metzler-Nolte, Nils

2014-06-01

312

Inhibition of p38 MAPK Signaling Augments Skin Tumorigenesis via NOX2 Driven ROS Generation  

Science.gov (United States)

p38 mitogen-activated protein kinases (MAPKs) respond to a wide range of extracellular stimuli. While the inhibition of p38 signaling is implicated in the impaired capacity to repair ultraviolet (UV)-induced DNA damage—a primary risk factor for human skin cancers—its mechanism of action in skin carcinogenesis remains unclear, as both anti-proliferative and survival functions have been previously described. In this study, we utilized cultured keratinocytes, murine tumorigenesis models, and human cutaneous squamous cell carcinoma (SCC) specimens to assess the effect of p38 in this regard. UV irradiation of normal human keratinocytes increased the expression of all four p38 isoforms (?/?/?/?); whereas irradiation of p53-deficient A431 keratinocytes derived from a human SCC selectively decreased p38?, without affecting other isoforms. p38? levels are decreased in the majority of human cutaneous SCCs assessed by tissue microarray, suggesting a tumor-suppressive effect of p38? in SCC pathogenesis. Genetic and pharmacological inhibition of p38? and in A431 cells increased cell proliferation, which was in turn associated with increases in NAPDH oxidase (NOX2) activity as well as intracellular reactive oxygen species (ROS). These changes led to enhanced invasiveness of A431 cells as assessed by the matrigel invasion assay. Chronic treatment of p53-/-/SKH-1 mice with the p38 inhibitor SB203580 accelerated UV-induced SCC carcinogenesis and increased the expression of NOX2. NOX2 knockdown suppressed the augmented growth of A431 xenografts treated with SB203580. These findings indicate that in the absence of p53, p38? deficiency drives SCC growth and progression that is associated with enhanced NOX2 expression and ROS formation. PMID:24824222

Liu, Liang; Rezvani, Hamid Reza; Back, Jung Ho; Hosseini, Mohsen; Tang, Xiuwei; Zhu, Yucui; Mahfouf, Walid; Raad, Houssam; Raji, Grace; Athar, Mohammad; Kim, Arianna L.; Bickers, David R.

2014-01-01

313

Selective anticancer copper(II)-mixed ligand complexes: targeting of ROS and proteasomes.  

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Copper compounds can be alternatives to platinum-based anticancer drugs. This study investigated the effects of a series of ternary copper(II) complexes, [Cu(phen)(aa)(H2O)]NO3·xH2O 1-4 (phen = 1,10-phenanthroline; aa = gly (1), DL-ala (2), sar (3), C-dmg (4)), on metastatic and cisplatin-resistant MDA-MB-231 breast cancer cells and MCF10A non-cancerous breast cells, and some aspects of the mechanisms. These complexes were distinctively more antiproliferative towards and induced greater apoptotic cell death in MDA-MB-231 than in MCF10A cells. 2 and 4 could induce cell cycle arrest only in cancer cells. Further evidence from DCFH-DA assay showed higher induction of reactive oxygen species (ROS) in treated cancer cells but minimal ROS increase in normal cells. DNA double-strand breaks, via a ?-H2AX assay, were only detected in cancer cells treated with 5 ?M of the complexes. These complexes poorly inhibited chymotrypsin-like activity in the 20S rabbit proteasome while they did not inhibit the three proteolytic sites of MDA-MB-231 cells at 10 ?M. However, the complexes could inhibit degradation of ubiquinated proteins of MDA-MB-231 cells. In addition, compound 4 was found to be effective against cervical (Hela), ovarian (SKOV3), lung (A549, PC9), NPC (Hone1, HK1, C666-1), breast (MCF7, T47D), lymphoma and leukemia (Nalmawa, HL60) and colorectal (SW480, SW48, HCT118) cancer cell lines with IC50 values (24 h) in the 1.7-19.0 ?M range. Single dose NCI60 screening of 4 showed the complex to be highly cytotoxic to most cancer cell types and more effective than cisplatin. PMID:24549332

Ng, Chew Hee; Kong, Siew Ming; Tiong, Yee Lian; Maah, Mohd Jamil; Sukram, Nurhazwani; Ahmad, Munirah; Khoo, Alan Soo Beng

2014-04-01

314

Attenuation of hydrogen peroxide-mediated oxidative stress by Brassica juncea annexin-3 counteracts thiol-specific antioxidant (TSA1) deficiency in Saccharomyces cerevisiae.  

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Brassica juncea annexin-3 (BjAnn3) was functionally characterized for its ability to modulate H2O2-mediated oxidative stress in Saccharomyces cerevisiae. BjAnn3 showed a significant protective role in cellular-defense against oxidative stress and partially alleviated inhibition of mitochondrial respiration in presence of exogenously applied H2O2. Heterologous expression of BjAnn3 protected membranes from oxidative stress-mediated damage and positively regulated antioxidant gene expression for ROS detoxification. We conclude that, BjAnn3 partially counteracts the effects of thioredoxin peroxidase 1 (TSA1) deficiency and aids in cellular-protection across kingdoms. Despite partial compensation of TSA1 by BjAnn3 in cell-viability tests, the over-complementation in ROS-related features suggests the existence of both redundant (e.g. ROS detoxification) and distinct features (e.g. membrane protection versus proximity-based redox regulator) of both proteins. PMID:24444602

Dalal, Ahan; Vishwakarma, Abhaypratap; Singh, Naveen Kumar; Gudla, Triveni; Bhattacharyya, Mrinal Kanti; Padmasree, Kollipara; Viehhauser, Andrea; Dietz, Karl-Josef; Kirti, Pulugurtha Bharadwaja

2014-02-14

315

DEXH box RNA helicase-mediated mitochondrial reactive oxygen species production in Arabidopsis mediates crosstalk between abscisic acid and auxin signaling.  

Science.gov (United States)

It is well known that abscisic acid (ABA) promotes reactive oxygen species (ROS) production through plasma membrane-associated NADPH oxidases during ABA signaling. However, whether ROS from organelles can act as second messengers in ABA signaling is largely unknown. Here, we identified an ABA overly sensitive mutant, abo6, in a genetic screen for ABA-mediated inhibition of primary root growth. ABO6 encodes a DEXH box RNA helicase that is involved in regulating the splicing of several genes of complex I in mitochondria. The abo6 mutant accumulated more ROS in mitochondria, as established using a mitochondrial superoxide indicator, circularly permuted yellow fluorescent protein. Two dominant-negative mutations in ABA insensitive1 (abi1-1) and abi2-1 greatly reduced ROS production in mitochondria. The ABA sensitivity of abo6 can also be compromised by the atrbohF mutation. ABA-mediated inhibition of seed germination and primary root growth in abo6 was released by the addition of reduced GSH and exogenous auxin to the medium. Expression of auxin-responsive markers ProDR5:GUS (for synthetic auxin response element D1-4 with site-directed mutants in the 5'-end from soybean):?-glucuronidase) and Indole-3-acetic acid inducible2:GUS was greatly reduced by the abo6 mutation. Hence, our results provide molecular evidence for the interplay between ABA and auxin through the production of ROS from mitochondria. This interplay regulates primary root growth and seed germination in Arabidopsis thaliana. PMID:22652060

He, Junna; Duan, Ying; Hua, Deping; Fan, Guangjiang; Wang, Li; Liu, Yue; Chen, Zhizhong; Han, Lihua; Qu, Li-Jia; Gong, Zhizhong

2012-05-01

316

Ceramide-Mediated Apoptosis in Lung Epithelial Cells Is Regulated by Glutathione  

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Reactive oxygen species (ROS) are mediators of lung injury, and glutathione (GSH) is the major nonprotein antioxidant that protects the cell from oxidative stress. We have recently shown that H2O2 induces ceramide-mediated apoptosis in human lung epithelial cells. We hypothesized that ROS-mediated depletion of GSH plays a regulatory role in ceramide generation, and thus in the induction of apoptosis. Our present studies demonstrate that GSH at physiologic concentrations (1 to 10 mM) inhibits ceramide production in a time- and dose-dependent manner in A549 human alveolar epithelial cells. On the other hand, buthionine-sulfoximine–mediated depletion of intracellular GSH induces elevation of ceramide levels and apoptosis. In addition, GSH blocks H2O2-mediated induction of intracellular ceramide generation and apoptosis. These effects were not mimicked by oxidized GSH (GSSG) or other thiol antioxidants, such as dithiothreitol and 2-mercaptoethanol. Moreover, increase of intracellular H2O2, mediated by inhibition of catalase by aminotriazole, also induces ceramide generation and apoptosis. These effects were blocked by N-acetylcysteine. Our results suggest that GSH depletion may be the link between oxidative stress and ceramide-mediated apoptosis in the lung. PMID:11726392

Lavrentiadou, Sophia N.; Chan, Chris; Kawcak, T’Nay; Ravid, Tommer; Tsaba, Adili; van der Vliet, Albert; Rasooly, Reuven; Goldkorn, Tzipora

2015-01-01

317

Arsenic trioxide synergistically enhances radiation response in human cervical cancer cells through ROS-dependent p38 MAPK and JNK signalling pathway  

International Nuclear Information System (INIS)

Many factors affect susceptibility of tumor cells to ionizing radiation. Among them intrinsic apoptosis sensitivity or resistancy seems to play an important role. The use of chemical modifiers as radiosensitizers in combination with low-dose irradiation may increase the therapeutic efficacy by overcoming a high apoptotic threshold. Several recent studies demonstrated additive effects of As2O3 with conventional chemotherapeutic agents such as cisplatin, adriamycin, and etoposide, but no synergism. Previously, we have shown for the first time that As2O3 sensitize human cervical cancer cells to ionizing radiation. Treatment of As2O3 in combination of ionizing radiation has synergistic effects in decreasing clonogenic survival and in the regression of tumor growth in xenografts. We also have shown that the combination treatment enhanced apoptotic cell death through a reactive oxygen species-dependent pathway in human cervical cancer cells. In this study, we investigated the regulatory mechanism of ROS-mediated mitochondrial apoptotic cell death induced by combination treatment with As2O3 and ionizing radiation in human cervical cancer cells

318

The RosR transcription factor is required for gene expression dynamics in response to extreme oxidative stress in a hypersaline-adapted archaeon  

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Full Text Available Abstract Background Previous work has shown that the hypersaline-adapted archaeon, Halobacterium salinarum NRC-1, is highly resistant to oxidative stress caused by exposure to hydrogen peroxide, UV, and gamma radiation. Dynamic alteration of the gene regulatory network (GRN has been implicated in such resistance. However, the molecular functions of transcription regulatory proteins involved in this response remain unknown. Results Here we have reanalyzed several existing GRN and systems biology datasets for H. salinarum to identify and characterize a novel winged helix-turn-helix transcription factor, VNG0258H, as a regulator required for reactive oxygen species resistance in this organism. This protein appears to be unique to the haloarchaea at the primary sequence level. High throughput quantitative growth assays in a deletion mutant strain implicate VNG0258H in extreme oxidative stress resistance. According to time course gene expression analyses, this transcription factor is required for the appropriate dynamic response of nearly 300 genes to reactive oxygen species damage from paraquat and hydrogen peroxide. These genes are predicted to function in repair of oxidative damage to proteins and DNA. In vivo DNA binding assays demonstrate that VNG0258H binds DNA to mediate gene regulation. Conclusions Together these results suggest that VNG0258H is a novel archaeal transcription factor that regulates gene expression to enable adaptation to the extremely oxidative, hypersaline niche of H. salinarum. We have therefore renamed VNG0258H as RosR, for reactive oxygen species regulator.

Sharma Kriti

2012-07-01

319

Natural borneol enhances bisdemethoxycurcumin-induced cell cycle arrest in the G2/M phase through up-regulation of intracellular ROS in HepG2 cells.  

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Bisdemethoxycurcumin (BDCur) has been found widely in foods such as cheese, butter, etc., and in curry (powder) as a spice. It has been reported to possess anticancer activity. However, its poor absorption limited its application. Natural borneol (NB) has been used as a promoter of drug absorption and widely used in candies, beverages, baked goods, chewing gum and other foods. Thus, we investigated whether NB could potentiate the cellular uptake of BDCur, and elucidated the molecular mechanisms of their combined inhibitory effects on HepG2 cells. Our results demonstrate that NB significantly enhanced the cellular uptake of BDCur. Induction of cell cycle arrest in HepG2 cells by NB and BDCur in combination was evidenced by accumulation of the G2/M cell population. Further investigation on the molecular mechanism showed that NB and BDCur in combination resulted in a significant decrease in the expression level of Cdc2 and cyclin B. Moreover, studies also found that ROS acted as an upstream mediator in NB/BDCur-induced HepG2 cell growth inhibition and led to DNA damage with up-regulation of the expression level of phosphorylated ATM and p53. Our findings suggest that the strategy of using NB and BDCur in combination may have promising potential applications in cancer chemoprevention. PMID:25537301

Chen, Jianping; Li, Lin; Su, Jianyu; Chen, Tianfeng

2015-03-11

320

Arsenic trioxide synergistically enhances radiation response in human cervical cancer cells through ROS-dependent p38 MAPK and JNK signalling pathway  

Energy Technology Data Exchange (ETDEWEB)

Many factors affect susceptibility of tumor cells to ionizing radiation. Among them intrinsic apoptosis sensitivity or resistancy seems to play an important role. The use of chemical modifiers as radiosensitizers in combination with low-dose irradiation may increase the therapeutic efficacy by overcoming a high apoptotic threshold. Several recent studies demonstrated additive effects of As{sub 2}O{sub 3} with conventional chemotherapeutic agents such as cisplatin, adriamycin, and etoposide, but no synergism. Previously, we have shown for the first time that As{sub 2}O{sub 3} sensitize human cervical cancer cells to ionizing radiation. Treatment of As{sub 2}O{sub 3} in combination of ionizing radiation has synergistic effects in decreasing clonogenic survival and in the regression of tumor growth in xenografts. We also have shown that the combination treatment enhanced apoptotic cell death through a reactive oxygen species-dependent pathway in human cervical cancer cells. In this study, we investigated the regulatory mechanism of ROS-mediated mitochondrial apoptotic cell death induced by combination treatment with As{sub 2}O{sub 3} and ionizing radiation in human cervical cancer cells.

Kang, Young-Hee; Park, Seung-Moo; Kim, Min-Jeong [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)] (and others)

2006-07-01

321

A deficiency of apoptosis inducing factor (AIF in Harlequin mouse heart mitochondria paradoxically reduces ROS generation during ischemia-reperfusion  

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Conclusion: A deficiency of AIF within mitochondria does not increase ROS production during IR, indicating that AIF functions less as an antioxidant within mitochondria. The decreased cardiac injury in Hq mouse heart accompanied by less AIF translocation to the nucleus suggests that AIF relocation, rather than the AIF content within mitochondria, contributes to cardiac injury during IR.

QunChen

2014-07-01

322

Asperlin induces G{sub 2}/M arrest through ROS generation and ATM pathway in human cervical carcinoma cells  

Energy Technology Data Exchange (ETDEWEB)

Highlights: {yields} A new anti-cancer effect of an antibiotics, asperlin, is exploited. {yields} Asperlin induced human cervical cancer cell apoptosis through ROS generation. {yields} Asperlin activated DNA-damage related ATM protein and cell cycle associated proteins. {yields} Asperlin could be developed as a new anti-cancer therapeutics. -- Abstract: We exploited the biological activity of an antibiotic agent asperlin isolated from Aspergillus nidulans against human cervical carcinoma cells. We found that asperlin dramatically increased reactive oxygen species (ROS) generation accompanied by a significant reduction in cell proliferation. Cleavage of caspase-3 and PARP and reduction of Bcl-2 could also be detected after asperlin treatment to the cells. An anti-oxidant N-acetyl-L-cysteine (NAC), however, blocked all the apoptotic effects of asperlin. The involvement of oxidative stress in asperlin induced apoptosis could be supported by the findings that ROS- and DNA damage-associated G2/M phase arrest and ATM phosphorylation were increased by asperlin. In addition, expression and phosphorylation of cell cycle proteins as well as G2/M phase arrest in response to asperlin were significantly blocked by NAC or an ATM inhibitor KU-55933 pretreatment. Collectively, our study proved for the first time that asperlin could be developed as a potential anti-cancer therapeutics through ROS generation in HeLa cells.

He, Long; Nan, Mei-Hua [Chemical Biology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 30 Yeongudanji-ro, Ochang-eup, Cheongwon-gun, Chungbuk 363-883 (Korea, Republic of); Oh, Hyun Cheol [College of Medical and Life Sciences, Silla University, 100 Silladaehak-gil, Sasang-gu, Busan 617-736 (Korea, Republic of); Kim, Young Ho [College of Pharmacy, ChungNam National University, Yuseong, Daejeon, 305-764 (Korea, Republic of); Jang, Jae Hyuk [Chemical Biology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 30 Yeongudanji-ro, Ochang-eup, Cheongwon-gun, Chungbuk 363-883 (Korea, Republic of); Erikson, Raymond Leo [Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138 (United States); Ahn, Jong Seog, E-mail: jsahn@kribb.re.kr [Chemical Biology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 30 Yeongudanji-ro, Ochang-eup, Cheongwon-gun, Chungbuk 363-883 (Korea, Republic of); Kim, Bo Yeon, E-mail: bykim@kribb.re.kr [Chemical Biology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 30 Yeongudanji-ro, Ochang-eup, Cheongwon-gun, Chungbuk 363-883 (Korea, Republic of); World Class Institute, KRIBB, 30 Yeongudanji-ro, Ochang-eup, Cheongwon-gun, Chungbuk 363-883 (Korea, Republic of)

2011-06-10

323

Mtf-1 lymphoma-susceptibility locus affects retention of large thymocytes with high ROS levels in mice after ?-irradiation  

International Nuclear Information System (INIS)

Mouse strains exhibit different susceptibilities to ?-ray-induced thymic lymphomas. Our previous study identified Mtf-1 (metal responsive transcription factor-1) as a candidate susceptibility gene, which is involved in the radiation-induced signaling pathway that regulates the cellular reactive oxygen species (ROS). To reveal the mechanism for the increased susceptibility conferred by Mtf-1 locus, we examined early effects of ?-ray on ROS levels in vivo and its difference between Mtf-1 susceptible and resistant congenic mice. Here, we show the detection of clonally growing thymocytes at 4 weeks after irradiation, indicating the start of clonal expansion at a very early stage. We also show that large thymocytes with higher ROS levels and a proliferation capacity were more numerous in the Mtf-1 susceptible mice than the resistant mice when examined at 7 days after irradiation, although such tendency was not found in mice lacking one allele of Bcl11b tumor suppressor gene. This high retention of the large thymocytes, at a high risk for ROS-induced mutation, is a compensatory proliferation and regeneration response to depletion of the thymocytes after irradiation and the response is likely to augment the development of prelymphoma cells leading to thymic lymphomas

324

Vorinostat and sorafenib increase CD95 activation in gastrointestinal tumor cells through a Ca2+ - de novo ceramide - PP2A - ROS dependent signaling pathway  

Science.gov (United States)

The targeted therapeutics sorafenib and vorinostat interact in a synergistic fashion to kill carcinoma cells by activating CD95, and this drug combination is entering phase I evaluation. In this study we determined how CD95 is activated by treatment with this drug combination. Low doses of sorafenib and vorinostat but not the individual drugs rapidly increased ROS, Ca2+ and ceramide levels in GI tumor cells. The production of ROS was reduced in Rho zero cells. Quenching ROS blocked drug-induced CD95 surface localization and apoptosis. ROS generation, CD95 activation and cell killing was also blocked by quenching of induced Ca2+ levels or by inhibition of PP2A. Inhibition of acidic sphingomyelinase or de novo ceramide generation blocked the induction of ROS however combined inhibition of both acidic sphingomyelinase and de novo ceramide generation was required to block the induction of Ca2+. Quenching of ROS did not impact on drug-induced ceramide/dihydro-ceramide levels whereas quenching of Ca2+ reduced the ceramide increase. Sorafenib and vorinostat treatment radiosensitized liver and pancreatic cancer cells, an effect that was suppressed by quenching ROS or knock down of LASS6. Further, sorafenib and vorinostat treatment suppressed the growth of pancreatic tumors in vivo. Our findings demonstrate that induction of cytosolic Ca2+ by sorafenib and vorinostat is a primary event that elevates dihydroceramide levels, each essential steps in ROS generation that promotes CD95 activation. PMID:20631069

Park, Margaret A.; Mitchell, Clint; Zhang, Guo; Yacoub, Adly; Allegood, Jeremy; Häussinger, Dieter; Reinehr, Roland; Larner, Andrew; Spiegel, Sarah; Fisher, Paul B.; Voelkel-Johnson, Christina; Ogretmen, Besim; Grant, Steven; Dent, Paul

2010-01-01

325

Production of hydrogen peroxide and expression of ROS generating genes in peach flower petals in response to host and non-host pathogens  

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Reactive oxygen species (ROS) play dual roles in plant-microbe interactions in that they can either stimulate host resistance or benefit pathogen virulence. Accumulation of ROS was determined in peach petals in response to Monilinia fructicola (a compatible pathogen) and Penicillium digitatum (an i...

326

TREATMENT OF BOAR SPERM WITH RESPIRATION INHIBITOR MENADIONE: EFFECTS ON MOTILITY, REACTIVE OXYGEN SPECIES (ROS), MITOCHONDRIAL TRANSMEMBRANE POTENTIAL (MMP), AND ATP CONTENT  

Science.gov (United States)

Previously we found that live, fresh or thawed boar sperm show little tendency to accumulate ROS spontaneously, but live sperm accumulated ROS during a 30 min incubation with xanthine and xanthine oxidase and showed marked reduction in motility. High MMP is required to drive the F0/F1 ATPase respons...

327

Cadmium-induced glutathionylation of actin occurs through a ROS-independent mechanism: Implications for cytoskeletal integrity  

Energy Technology Data Exchange (ETDEWEB)

Cadmium disrupts the actin cytoskeleton in rat mesangial cells, and we have previously shown that this involves a complex interplay involving activation of kinase signaling, protein translocation, and disruption of focal adhesions. Here we investigate the role that glutathionylation of actin plays in Cd{sup 2+}-associated cytoskeletal reorganization. Low concentrations of Cd{sup 2+} (0.5–2 ?M) caused an increase in actin glutathionylation by 6 h, whereas at higher concentrations glutathionylation remained at basal levels. Although oxidation with diamide increased glutathionylation, reactive oxygen species (ROS) were not involved in the Cd{sup 2+}-dependent effect, as only Cd{sup 2+} concentrations above 2 ?M were sufficient to increase ROS. However, low [Cd{sup 2+}] increased total glutathione levels without affecting the ratio of reduced/oxidized glutathione, and inhibition of glutathione synthesis suppressed actin glutathionylation. Cadmium increased the activity of the enzyme glutaredoxin, which influences the equilibrium between glutathionylated and deglutathionylated proteins and thus may influence levels of glutathionylated actin. Together these observations show that cadmium-dependent effects on actin glutathionylation are affected by glutathione metabolism and not by direct effects of ROS on thiol chemistry. In vitro polymerization assays with glutathionylated actin show a decreased rate of polymerization. In contrast, immunofluorescence of cytoskeletal structure in intact cells suggests that increases in actin glutathionylation accompanying increased glutathione levels occurring under low Cd{sup 2+} exposure are protective in vivo, with cytoskeletal disruption ensuing only when higher Cd{sup 2+} concentrations increase ROS levels and prevent an increase in actin–glutathione conjugates. - Highlights: • Cadmium disrupts the actin cytoskeleton in mesangial cells. • Cadmium induces glutathionylation of actin at low concentrations. • Glutathionylation requires glutathione synthesis but is independent of ROS. • Glutathionylation is protective against cytoskeletal disruption at low cadmium.

Choong, Grace; Liu, Ying; Xiao, Weiqun; Templeton, Douglas M., E-mail: doug.templeton@utoronto.ca

2013-10-15

328

Mitochondria-targeted ROS scavenger improves post-ischemic recovery of cardiac function and attenuates mitochondrial abnormalities in aged rats.  

Science.gov (United States)

Mitochondria-generated reactive oxygen species (ROS) play a crucial role in the pathogenesis of aging and age-associated diseases. In this study, we evaluated the effects of XJB-5-131 (XJB), a mitochondria-targeted ROS and electron scavenger, on cardiac resistance to ischemia-reperfusion (IR)-induced oxidative stress in aged rats. Male adult (5-month old, n=17) and aged (29-month old, n=19) Fischer Brown Norway (F344/BN) rats were randomly assigned to the following groups: adult (A), adult+XJB (AX), aged (O), and aged+XJB (OX). XJB was administered 3 times per week (3mg/kg body weight, IP) for four weeks. At the end of the treatment period, cardiac function was continuously monitored in excised hearts using the Langendorff technique for 30 min, followed by 20 min of global ischemia, and 60-min reperfusion. XJB improved post-ischemic recovery of aged hearts, as evidenced by greater left ventricular developed-pressures and rate-pressure products than the untreated, aged-matched group. The state 3 respiration rates at complexes I, II and IV of mitochondria isolated from XJB-treated aged hearts were 57% (Prats. In addition, XJB significantly attenuated the H2O2-induced depolarization of the mitochondrial inner membrane as well as the total and mitochondrial ROS levels in cultured cardiomyocytes. This study underlines the importance of mitochondrial ROS in aging-induced cardiac dysfunction and suggests that targeting mitochondrial ROS may be an effective therapeutic approach to protect the aged heart against IR injury. PMID:25451170

Escobales, Nelson; Nuñez, Rebeca E; Jang, Sehwan; Parodi-Rullan, Rebecca; Ayala-Peña, Sylvette; Sacher, Joshua R; Skoda, Erin M; Wipf, Peter; Frontera, Walter; Javadov, Sabzali

2014-12-01

329

Nonthermal Plasma Induces Apoptosis in ATC Cells: Involvement of JNK and p38 MAPK-Dependent ROS  

Science.gov (United States)

Purpose To determine the effects of nonthermal plasma (NTP) induced by helium (He) alone or He plus oxygen (O2) on the generation of reactive oxygen species (ROS) and cell death in anaplastic thyroid cancer cells. Materials and Methods NTP was generated in He alone or He plus O2 blowing through a nozzle by applying a high alternating current voltage to the discharge electrodes. Optical emission spectroscopy was used to identify various excited plasma species. The apoptotic effect of NTP on the anaplastic thyroid cancer cell lines, such as HTH83, U-HTH 7, and SW1763, was verified with annexin V/propidium staining and TUNEL assay. ROS formation after NTP treatment was identified with fluorescence-activated cell sorting with DCFDA staining. The mitogen-activated protein kinase pathways and caspase cascade were investigated to evaluate the molecular mechanism involved and cellular targets of plasma. Results NTP induced significant apoptosis in all three cancer cell lines. The plasma using He and O2 generated more O2-related species, and increased apoptosis and intracellular ROS formation compared with the plasma using He alone. NTP treatment of SW1763 increased the expression of phosphor-JNK, phosphor-p38, and caspase-3, but not phosphor-ERK. Apoptosis of SW1763 as well as expressions of elevated phosphor-JNK, phosphor-p38, and caspase-3 induced by NTP were effectively inhibited by intracellular ROS scavengers. Conclusion NTP using He plus O2 induced significant apoptosis in anaplastic cancer cell lines through intracellular ROS formation. This may represent a new promising treatment modality for this highly lethal disease. PMID:25323903

Lee, Sei Young; Kang, Sung Un; Kim, Kang Il; Kang, Sam; Shin, Yoo Seob; Chang, Jae Won; Yang, Sang Sik; Lee, Keunho; Lee, Jong-Soo; Moon, Eunpyo

2014-01-01

330

Hitting the Bull's-Eye in Metastatic Cancers-NSAIDs Elevate ROS in Mitochondria, Inducing Malignant Cell Death.  

Science.gov (United States)

Tumor metastases that impede the function of vital organs are a major cause of cancer related mortality. Mitochondrial oxidative stress induced by hypoxia, low nutrient levels, or other stresses, such as genotoxic events, act as key drivers of the malignant changes in primary tumors to enhance their progression to metastasis. Emerging evidence now indicates that mitochondrial modifications and mutations resulting from oxidative stress, and leading to OxPhos stimulation and/or enhanced reactive oxygen species (ROS) production, are essential for promoting and sustaining the highly metastatic phenotype. Moreover, the modified mitochondria in emerging or existing metastatic cancer cells, by their irreversible differences, provide opportunities for selectively targeting their mitochondrial functions with a one-two punch. The first blow would block their anti-oxidative defense, followed by the knockout blow-promoting production of excess ROS, capitulating the terminal stage-activation of the mitochondrial permeability transition pore (mPTP), specifically killing metastatic cancer cells or their precursors. This review links a wide area of research relevant to cellular mechanisms that affect mitochondria activity as a major source of ROS production driving the pro-oxidative state in metastatic cancer cells. Each of the important aspects affecting mitochondrial function are discussed including: hypoxia, HIFs and PGC1 induced metabolic changes, increased ROS production to induce a more pro-oxidative state with reduced antioxidant defenses. It then focuses on how the mitochondria, as a major source of ROS in metastatic cancer cells driving the pro-oxidative state of malignancy enables targeting drugs affecting many of these altered processes and why the NSAIDs are an excellent example of mitochondria-targeted agents that provide a one-two knockout activating the mPTP and their efficacy as selective anticancer metastasis drugs. PMID:25688484

Ralph, Stephen John; Pritchard, Rhys; Rodríguez-Enríquez, Sara; Moreno-Sánchez, Rafael; Ralph, Raymond Keith

2015-01-01

331

Reactive oxygen species regulated mitochondria-mediated apoptosis in PC12 cells exposed to chlorpyrifos  

International Nuclear Information System (INIS)

Reactive oxidative species (ROS) generated by environmental toxicants including pesticides could be one of the factors underlying the neuronal cell damage in neurodegenerative diseases. In this study we found that chlorpyrifos (CPF) induced apoptosis in dopaminergic neuronal components of PC12 cells as demonstrated by the activation of caspases and nuclear condensation. Furthermore, CPF also reduced the tyrosine hydroxylase-positive immunoreactivity in substantia nigra of the rat. In addition, CPF induced inhibition of mitochondrial complex I activity. Importantly, N-acetyl cysteine (NAC) treatment effectively blocked apoptosis via the caspase-9 and caspase-3 pathways while NAC attenuated the inhibition of mitochondrial complex I activity as well as the oxidative metabolism of dopamine (DA). These results demonstrated that CPF-induced apoptosis was involved in mitochondrial dysfunction through the production of ROS. In the response of cellular antioxidant systems to CPF, we found that CPF treatment increased HO-1 expression while the expression of CuZnSOD and MnSOD was reduced. In addition, we found that CPF treatment activated MAPK pathways, including ERK 1/2, the JNK, and the p38 MAP kinase in a time-dependent manner. NAC treatment abolished MAPK phosphorylation caused by CPF, indicating that ROS are upstream signals of MAPK. Interestingly, MAPK inhibitors abolished cytotoxicity and reduced ROS generation by CPF treatment. Our results demonstrate that CPF induced neuronal cell death in part through MAPK activation via ROS generation, suggesting its potential to generate oxidative stress via mitochondrial damage and its involvement in oxidative stress-related neurodegenerative disease. -- Highlights: ? Chlorpyrifos induces apoptosis. ? Chlorpyrifos inhibits mitochondrial complex I activity. ? ROS is involved in chlorpyrifos-induced apoptosis. ? Chlorpyrifos affects cellular antioxidant systems. ? Chlorpyrifos-induced apoptosis mediates activation of MAPK.

332

Reactive oxygen species regulated mitochondria-mediated apoptosis in PC12 cells exposed to chlorpyrifos  

Energy Technology Data Exchange (ETDEWEB)

Reactive oxidative species (ROS) generated by environmental toxicants including pesticides could be one of the factors underlying the neuronal cell damage in neurodegenerative diseases. In this study we found that chlorpyrifos (CPF) induced apoptosis in dopaminergic neuronal components of PC12 cells as demonstrated by the activation of caspases and nuclear condensation. Furthermore, CPF also reduced the tyrosine hydroxylase-positive immunoreactivity in substantia nigra of the rat. In addition, CPF induced inhibition of mitochondrial complex I activity. Importantly, N-acetyl cysteine (NAC) treatment effectively blocked apoptosis via the caspase-9 and caspase-3 pathways while NAC attenuated the inhibition of mitochondrial complex I activity as well as the oxidative metabolism of dopamine (DA). These results demonstrated that CPF-induced apoptosis was involved in mitochondrial dysfunction through the production of ROS. In the response of cellular antioxidant systems to CPF, we found that CPF treatment increased HO-1 expression while the expression of CuZnSOD and MnSOD was reduced. In addition, we found that CPF treatment activated MAPK pathways, including ERK 1/2, the JNK, and the p38 MAP kinase in a time-dependent manner. NAC treatment abolished MAPK phosphorylation caused by CPF, indicating that ROS are upstream signals of MAPK. Interestingly, MAPK inhibitors abolished cytotoxicity and reduced ROS generation by CPF treatment. Our results demonstrate that CPF induced neuronal cell death in part through MAPK activation via ROS generation, suggesting its potential to generate oxidative stress via mitochondrial damage and its involvement in oxidative stress-related neurodegenerative disease. -- Highlights: ? Chlorpyrifos induces apoptosis. ? Chlorpyrifos inhibits mitochondrial complex I activity. ? ROS is involved in chlorpyrifos-induced apoptosis. ? Chlorpyrifos affects cellular antioxidant systems. ? Chlorpyrifos-induced apoptosis mediates activation of MAPK.

Lee, Jeong Eun [Department of Pharmacology, College of Medicine, Hanyang University, Seoul (Korea, Republic of); Hanyang Biomedical Research Institute, Seoul (Korea, Republic of); Park, Jae Hyeon [Hanyang Biomedical Research Institute, Seoul (Korea, Republic of); Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul (Korea, Republic of); Shin, In Chul [Department of Pharmacology, College of Medicine, Hanyang University, Seoul (Korea, Republic of); Koh, Hyun Chul, E-mail: hckoh@hanyang.ac.kr [Department of Pharmacology, College of Medicine, Hanyang University, Seoul (Korea, Republic of); Hanyang Biomedical Research Institute, Seoul (Korea, Republic of); Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul (Korea, Republic of)

2012-09-01

333

Essential role of Drosophila black-pearl is mediated by its effects on mitochondrial respiration  

OpenAIRE

Black-pearl (Blp) is a highly conserved, essential inner-mitochondrial membrane protein. The yeast Blp homologue, Magmas/Pam16, is required for mitochondrial protein transport, growth, and survival. Our purpose was to determine the role of Drosophila Blp in mitochondrial function, cell survival, and proliferation. To this end, we performed mitotic recombination in Drosophila melanogaster, RNAi-mediated knockdown, MitoTracker staining, measurement of reactive oxygen species (ROS), flow cytomet...

Roy, Soumit; Short, Mary K.; Stanley, E. Richard; Jubinsky, Paul T.

2012-01-01

334

Safflor yellow B suppresses angiotensin II-mediated human umbilical vein cell injury via regulation of Bcl-2/p22{sup phox} expression  

Energy Technology Data Exchange (ETDEWEB)

Intracellular reactive oxygen species (ROS) are derived from nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Angiotensin II (Ang II) can cause endothelial dysfunction by promoting intracellular ROS generation. Safflor yellow B (SYB) effectively inhibits ROS generation by upregulating Bcl-2 expression. In this study, we examined the effects of SYB on Ang II-induced injury to human umbilical vein endothelial cells (HUVECs), and elucidated the roles of NADPH oxidase and Bcl-2. We treated cultured HUVECs with Ang II, SYB, and Bcl-2 siRNA, and determined NADPH oxidase activity and ROS levels. Furthermore, cellular and mitochondrial physiological states were evaluated, and the expression levels of target proteins were analyzed. Ang II significantly enhanced intracellular ROS levels, caused mitochondrial membrane dysfunction, and decreased cell viability, leading to apoptosis. This was associated with increased expression of AT1R and p22{sup phox}, increased NADPH oxidase activity, and an increased ratio of Bax/Bcl-2, leading to decreases in antioxidant enzyme activities, which were further strengthened after blocking Bcl-2. Compared to Ang II treatment alone, co-treatment with SYB significantly reversed HUVEC injury. Taken together, these results demonstrate that SYB could significantly protect endothelial cells from Ang II-induced cell damage, and that it does so by upregulating Bcl-2 expression and inhibiting ROS generation. - Highlights: • Angiotensin II depresses mitochondria physiological function. • Angiotensin II activates NADPH oxidase via up-regulating expresion of p22{sup phox}. • Bcl-2 plays a pivotal role in improving mitochondria function and regulates ROS level. • Inhibitor of Bcl-2 promotes angiotensin II mediated HUVEC injury. • SYB attenuates angiotensin II mediated HUVEC injury via up regulating Bcl-2 expression.

Wang, Chaoyun; He, Yanhao [School of Pharmaceutical Sciences, Binzhou Medical University, Yantai, Shandong 264003 (China); Department of Pharmacology, Xi' an Jiaotong University School of Medicine, Key Laboratory of Environment and Genes Related to Disease, Ministry of Education, Xi' an, Shaanxi 710061 (China); Yang, Ming; Sun, Hongliu; Zhang, Shuping [School of Pharmaceutical Sciences, Binzhou Medical University, Yantai, Shandong 264003 (China); Wang, Chunhua, E-mail: chunhuawang2012@163.com [School of Pharmaceutical Sciences, Binzhou Medical University, Yantai, Shandong 264003 (China)

2013-11-15

335

A chemical genetic approach demonstrates that MPK3/MPK6 activation and NADPH oxidase-mediated oxidative burst are two independent signaling events in plant immunity  

Science.gov (United States)

Summary Plant recognition of pathogen-associated molecular patterns (PAMPs) such as bacterial flagellin-derived flg22 triggers rapid activation of mitogen-activated protein kinases (MAPKs) and generation of reactive oxygen species (ROS). Arabidopsis has at least four PAMP/pathogen-responsive MAPKs: MPK3, MPK6, MPK4, and MPK11. It was speculated that these MAPKs may function downstream of ROS in plant immunity because of their activation by exogenously added H2O2. MPK3/MPK6 or their orthologs in other plant species were also reported to be involved in ROS burst from the plant respiratory burst oxidase homologue (Rboh) of human neutrophil gp91phox. However, detailed genetic analysis is lacking. Using a chemical genetic approach, we generated another conditional loss-of-function mpk3 mpk6 double mutant. Together with the conditionally rescued mpk3 mpk6 double mutant reported previously, we demonstrate that flg22-triggered ROS burst is independent of MPK3/MPK6. In Arabidopsis mutant lacking a functional AtRbohD, flg22-induced ROS burst was completely blocked. However, the activation of MPK3/MPK6 was not affected. Based on these results, we conclude that the rapid ROS burst and MPK3/MPK6 activation are two independent early signaling events downstream of FLS2 in plant immunity. We also found that MPK4 negatively impacts the flg22-induced ROS burst. In addition, salicylic acid-pretreatment enhances AtRbohD-mediated ROS burst, which is again independent of MPK3/MPK6 based on the analysis of mpk3 mpk6 double mutant. The establishment of a mpk3 mpk6 double mutant system using the chemical genetic approach offers us a powerful tool to investigate the function of MPK3/MPK6 in plant defense signaling pathway. PMID:24245741

Xu, Juan; Xie, Jie; Yan, Chengfei; Zou, Xiaoqin; Ren, Dongtao; Zhang, Shuqun

2014-01-01

336

Mitochondrial cyclophilin-D as a critical mediator of ischaemic preconditioning  

Science.gov (United States)

Aims It has been suggested that mitochondrial reactive oxygen species (ROS), Akt and Erk1/2 and more recently the mitochondrial permeability transition pore (mPTP) may act as mediators of ischaemic preconditioning (IPC), although the actual interplay between these mediators is unclear. The aim of the present study is to determine whether the cyclophilin-D (CYPD) component of the mPTP is required by IPC to generate mitochondrial ROS and subsequently activate Akt and Erk1/2. Methods and results Mice lacking CYPD (CYPD?/?) and B6Sv129 wild-type (WT) mice were used throughout. We have demonstrated that under basal conditions, non-pathological mPTP opening occurs (indicated by the percent reduction in mitochondrial calcein fluorescence). This effect was greater in WT cardiomyocytes compared with CYPD?/? ones (53 ± 2% WT vs. 17 ± 3% CYPD?/?; P 0.05). HPC generated mitochondrial ROS in WT (four-fold increase; P < 0.05) but not CYPD?/? cardiomyocytes. HPC induced significant Akt phosphorylation in WT cardiomyocytes (two-fold increase; P < 0.05), an effect which was abrogated by ciclosporin-A (a CYPD inhibitor) and N-2-mercaptopropionyl glycine (a ROS scavenger). Finally, in vivo IPC of adult murine hearts resulted in significant phosphorylation of Akt and Erk1/2 in WT but not CYPD?/? hearts. Conclusion The CYPD component of the mPTP is required by IPC to generate mitochondrial ROS and phosphorylate Akt and Erk1/2, major steps in the IPC signalling pathway. PMID:20400621

Hausenloy, Derek J.; Lim, Shiang Y.; Ong, Sang-Ging; Davidson, Sean M.; Yellon, Derek M.

2010-01-01

337

Endogenous nitric oxide in Pseudomonas fluorescens ZY2 as mediator against the combined exposure to zinc and cefradine.  

Science.gov (United States)

A better understanding on the mechanism involved in bacterial resistance to combined exposure to antibiotics and heavy metals is helpful in implementing practices to mitigate their ecological risk and spread of resistance genes in microbial population. Pseudomonas fluorescens ZY2, a strain isolated from swine wastewater, was chosen to study its growth (bacterial density OD600), the formation of reactive oxygen species (ROS), nitric oxide (NO) and NO synthases (NOS) under Zn, cefradine or Zn + cefradine treatments. Using Zn and cefradine as representative heavy metal and antibiotic in this investigation, respectively, the resistance of P. fluorescens ZY2 to toxic chemical exposure was investigated. Bacterial densities of treatment groups significantly increased over the time of incubation, but less than the control. ROS, NO and NOS initially increased, but then decreased after the initial 8 h of culturing, and were positively related to Zn concentrations. Moreover, the formation of ROS, NOS, and NO was activated by cefradine at Zn of up to 160 mg/L, but inhibited at Zn of 200 mg/L whether cefradine was added or not. Zn concentration affected ROS and NO concentrations between treatments and also was closely related to the variation of the relative bacterial density. For P. fluorescens ZY2, the mediation of endogenous NO to overcome ROS in response to the combined exposure of Zn and cefradine was suggested as a co-resistance mechanism, which would be beneficial to evaluate the ecological risk of heavy metals and antibiotics. PMID:25678231

Xu, Yan-Bin; Zhou, Yan; Ruan, Jing-Jing; Xu, Shi-Hui; Gu, Ji-Dong; Huang, Shao-Song; Zheng, Li; Yuan, Bao-Hong; Wen, Li-Hua

2015-05-01

338

Beauvericin-induced cytotoxicity via ROS production and mitochondrial damage in Caco-2 cells.  

Science.gov (United States)

The cytotoxicity of beauvericin (BEA) on human colon adenocarcinoma (Caco-2) cells was studied as a function of time. Moreover, the oxidative damage and cell death endpoints were monitored after 24, 48 and 72 h. After BEA exposure, the IC?? values ranged from 1.9 ± 0.7 to 20.6 ± 6.9 ?M. A decrease in reduced glutathione (GSH; 31%) levels, as well as an increase in oxidized glutathione (GSSG, 20%) was observed. In the presence of BEA, reactive oxygen species (ROS) level was highly increased at an early stage with the highest production of 2.0-fold higher than the control that was observed at 120 min. BEA induced cell death by mitochondria-dependent apoptotic process with loss of the mitochondrial membrane potential (??m; 9% compared to the control), increase in LPO level (from 120% to 207% compared to the control) and reduced G0/G1 phase, with an arrest in G2/M, in a dose and time-dependent manner. Cell proliferation, apoptosis and ??m determined, were in a dose- time-dependent manner. Moreover, DNA damage was observed after 12.0 ?M concentration. This study demonstrated that oxidative stress is one of the mechanism involved in BEA toxicity, moreover apoptosis induction and loss of ??m contribute to its cytotoxicity in Caco-2 cells. PMID:23850777

Prosperini, A; Juan-García, A; Font, G; Ruiz, M J

2013-10-24

339

Cordyceps sinensis polysaccharide inhibits PDGF-BB-induced inflammation and ROS production in human mesangial cells.  

Science.gov (United States)

CPS-F, a polysaccharide derived from Cordyceps sinensis, is a potential anti-inflammatory and anti-oxidative agent. We demonstrated that CPS-F not only inhibits platelet-derived growth factor BB (PDGF-BB)-induced intracellular reactive oxygen species (ROS) generation, and up-regulation of tumor necrosis factor-? (TNF-?), TNF-? receptor 1 (TNFR1), and monocyte chemotactic protein-1 (MCP-1), but also acts synergistically in combination with MAPK/ERK inhibitor U0126 and PI3K/Akt inhibitor LY294002. Additionally, up-regulation of pro-inflammatory factors was reversed by use of a combination of CPS-F and NADPH oxidase (NOX) inhibitor diphenyleneiodonium chloride (DPI) or silencing of NOX1. Furthermore, CPS-F prevents the PDGF receptor ? (PDGFR?) promoter activity induced by PDGF-BB in transfected cells and ameliorates increased levels of TNF-?, TNFR1, and MCP-1 when PDGFR? is silenced, thereby suggesting that CPS-F possesses a bidirectional regulatory function. Our findings suggest CPS-F may exert its therapeutic effect for the treatment of glomerulonephritis related to human mesangial cells (HMCs) through the ERK1/2/Akt pathways. PMID:25857968

Wang, Ying; Wang, Yan; Liu, Dan; Wang, Wang; Zhao, Huan; Wang, Min; Yin, Hongping

2015-07-10

340

In Vitro Cytotoxic Evaluation of MgO Nanoparticles and Their Effect on the Expression of ROS Genes  

Directory of Open Access Journals (Sweden)

Full Text Available Water-dispersible MgO nanoparticles were tested to investigate their cytotoxic effects on oxidative stress gene expression. In this in vitro study, genes related to reactive oxygen species (ROS, glutathione S-transferase (GST and catalase, were quantified using real-time polymerase chain reactions (molecular level and molecular beacon technologies (cellular level. The monodispersed MgO nanoparticles, 20 nm in size, were used to treat human cancer cell lines (liver cancer epithelial cells at different concentrations (25, 75 and 150 µg/mL and incubation times (24, 48 and 72 h. Both the genetic and cellular cytotoxic screening methods produced consistent results, showing that GST and catalase ROS gene expression was maximized at 150 µg/mL nanoparticle treatment with 48 h incubation. However, the genotoxic effect of MgO nanoparticles was not significant compared with control experiments, which indicates its significant potential applications in nanomedicine as a diagnostic and therapeutic tool.

Rangarajulu Senthil Kumaran

2015-04-01

341

In Vitro Cytotoxic Evaluation of MgO Nanoparticles and Their Effect on the Expression of ROS Genes.  

Science.gov (United States)

Water-dispersible MgO nanoparticles were tested to investigate their cytotoxic effects on oxidative stress gene expression. In this in vitro study, genes related to reactive oxygen species (ROS), glutathione S-transferase (GST) and catalase, were quantified using real-time polymerase chain reactions (molecular level) and molecular beacon technologies (cellular level). The monodispersed MgO nanoparticles, 20 nm in size, were used to treat human cancer cell lines (liver cancer epithelial cells) at different concentrations (25, 75 and 150 µg/mL) and incubation times (24, 48 and 72 h). Both the genetic and cellular cytotoxic screening methods produced consistent results, showing that GST and catalase ROS gene expression was maximized at 150 µg/mL nanoparticle treatment with 48 h incubation. However, the genotoxic effect of MgO nanoparticles was not significant compared with control experiments, which indicates its significant potential applications in nanomedicine as a diagnostic and therapeutic tool. PMID:25854426

Kumaran, Rangarajulu Senthil; Choi, Yong-Keun; Singh, Vijay; Song, Hak-Jin; Song, Kyung-Guen; Kim, Kwang Jin; Kim, Hyung Joo

2015-01-01

342

Mitochondrial aquaporin-8-mediated hydrogen peroxide transport is essential for teleost spermatozoon motility.  

Science.gov (United States)

Reactive oxygen species (ROS), particularly hydrogen peroxide (H2O2), cause oxidative cell damage and inhibit sperm function. In most oviparous fishes that spawn in seawater (SW), spermatozoa may be exposed to harmful ROS loads associated with the hyperosmotic stress of axonemal activation and ATP synthesis from mitochondrial oxidative phosphorylation. However, it is not known how marine spermatozoa can cope with the increased ROS levels to maintain flagellar motility. Here, we show that a marine teleost orthologue of human aquaporin-8, termed Aqp8b, is rapidly phosphorylated and inserted into the inner mitochondrial membrane of SW-activated spermatozoa, where it facilitates H2O2 efflux from this compartment. When Aqp8b intracellular trafficking and mitochondrial channel activity are immunologically blocked in activated spermatozoa, ROS levels accumulate in the mitochondria leading to mitochondrial membrane depolarisation, the reduction of ATP production, and the progressive arrest of sperm motility. However, the decreased sperm vitality underlying Aqp8b loss of function is fully reversed in the presence of a mitochondria-targeted antioxidant. These findings reveal a previously unknown detoxification mechanism in spermatozoa under hypertonic conditions, whereby mitochondrial Aqp8b-mediated H2O2 efflux permits fuel production and the maintenance of flagellar motility. PMID:25586329

Chauvigné, François; Boj, Mónica; Finn, Roderick Nigel; Cerdà, Joan

2015-01-01

343

Mesenchymal Stromal Cells Protect Cancer Cells From ROS-induced Apoptosis and Enhance the Warburg Effect by Secreting STC1  

OpenAIRE

Previous studies have demonstrated that mesenchymal stromal cells (MSCs) enhance cell survival through upregulation and secretion of stanniocalcin-1 (STC1). This study shows that MSC-derived STC1 promotes survival of lung cancer cells by uncoupling oxidative phosphorylation, reducing intracellular reactive oxygen species (ROS), and shifting metabolism towards a more glycolytic metabolic profile. MSC-derived STC1 upregulated uncoupling protein 2 (UCP2) in injured A549 cells in an STC1-dependen...

Ohkouchi, Shinya; Block, Gregory J.; Katsha, Ahmed M.; Kanehira, Masahiko; Ebina, Masahito; Kikuchi, Toshiaki; Saijo, Yasuo; Nukiwa, Toshihiro; Prockop, Darwin J.

2011-01-01

344

Reactive oxygen and nitrogen (ROS and RNS) species generation and cell death in tomato suspension cultures—Botrytis cinerea interaction  

OpenAIRE

This article reports events connected to cell survival and Botrytis cinerea infection development in cell suspension cultures of two tomato cultivars which show different levels of susceptibility to the pathogen: cv. Corindo (more susceptible) and cv. Perkoz (less susceptible). In parallel changes in reactive oxygen (ROS) and nitrogen (RNS) species generation and in S-nitrosoglutathione reductase (GSNOR) activity were studied. In vivo staining methods with acridine orange (AO) and ethidium br...

Pietrowska, E.; Ro?z?alska, S.; Kaz?mierczak, A.; Nawrocka, J.; Ma?olepsza, U.

2014-01-01

345

HBx co-localizes with COXIII in HL-7702 cells to upregulate mitochondrial function and ROS generation.  

Science.gov (United States)

Hepatocellular carcinoma (HCC) is one of the most common malignant diseases, and HBx leads to the development of HBV-associated HCC. Mitochondria are key organelles that regulate apoptosis, cellular energetics and signal transduction pathways, and are the source of HBx-induced reactive oxygen species (ROS). Recent findings have shown that HBx interacts with the inner mitochondrial membrane protein, COXIII, via the yeast two?hybrid system, mating experiment and coimmunoprecipitation. The aim of the present study was to examine the co-localizaiton of HBx and COXIII in HL-7702 cells and to investigate ensuing alterations of mitochondrial function. An HL-7702 cell line stably expressing the HBx gene by lentivirus vectors was constructed. Confocal microscopy was utilized to assess the interaction between HBx protein and COXIII. Expression of COXIII, activities of cytochrome c oxidase (COX) and the mitochondrial membrane potential, which were functionally relevant to the HBx protein-COXIII interaction, were investigated in cell cultures. Moreover, the intracellular ROS levels were detected by flow cytometry. The results demonstrated that HBx co-localized with the inner mitochondrial protein, COXIII, in HL-7702 cells, causing the upregulation of COXIII protein expression as well as COX activity. However, HBx did not alter the mitochondrial membrane potential and mitochondria exhibited only slight swelling in HL-7702-HBx cells. Moreover, HBx elevated the generation of mitochondrial ROS in HL-7702-HBx cells. The main finding of the present study was that the co-localization of HBx and COXIII leads to upregulation of the mitochondrial function and ROS generation, which are associated with the oncogenesis of HBV-associated HCC. PMID:25778742

Zou, Lai-Yu; Zheng, Bi-Yun; Fang, Xue-Fen; Li, Dan; Huang, Yue-Hong; Chen, Zhi-Xin; Zhou, Lin-Ying; Wang, Xiao-Zhong

2015-05-01

346

Plumbagin Inhibits Proliferative and Inflammatory Responses of T Cells Independent of ROS Generation But by Modulating Intracellular Thiols  

OpenAIRE

Plumbagin inhibited activation, proliferation, cytokine production, and graft-versus-host disease in lymphocytes and inhibited growth of tumor cells by suppressing nuclear factor-?B (NF-?B). Plumbagin was also shown to induce reactive oxygen species (ROS) generation in tumor cells via an unknown mechanism. Present report describes a novel role of cellular redox in modulation of immune responses in normal lymphocytes by plumbagin. Plumbagin depleted glutathione (GSH) levels that led to incre...

Checker, Rahul; Sharma, Deepak; Sandur, Santosh K.; Subrahmanyam, G.; Krishnan, Sunil; Poduval, T. B.; Sainis, K. B.

2010-01-01

347

Enterococcus faecalis infection causes inflammation, intracellular oxphos-independent ROS production, and DNA damage in human gastric cancer cells  

DEFF Research Database (Denmark)

Achlorhydria caused by e.g. atrophic gastritis allows for bacterial overgrowth, which induces chronic inflammation and damage to the mucosal cells of infected individuals driving gastric malignancies and cancer. Enterococcus faecalis (E. faecalis) can colonize achlohydric stomachs and we therefore wanted to study the impact of E. faecalis infection on inflammatory response, reactive oxygen species (ROS) formation, mitochondrial respiration, and mitochondrial genetic stability in gastric mucosal cells.

Strickertsson, Jesper A B; Madsen, Claus Desler

2013-01-01

348

Artemisinin dimer anti-cancer activity correlates with heme-catalyzed ROS generation and ER stress induction  

OpenAIRE

Analogs of the malaria therapeutic, artemisinin, possess in vitro and in vivo anti-cancer activity. In this study, two dimeric artemisinins (NSC724910 and 735847) were studied to determine their mechanism of action. Dimers were >1000 fold more active than monomer and treatment was associated with increased reactive oxygen species (ROS) and apoptosis induction. Dimer activity was inhibited by the anti-oxidant L-NAC, the iron chelator desferroxamine, and exogenous hemin. Similarly, induction of...

Stockwin, Luke H.; Han, Bingnan; Yu, Sherry X.; Hollingshead, Melinda G.; Elsohly, Mahmoud A.; Gul, Waseem; Slade, Desmond; Galal, Ahmed M.; Newton, Dianne L.

2009-01-01

349

ROS generated by pollen NADPH oxidase provide a signal that augments antigen-induced allergic airway inflammation  

OpenAIRE

Pollen exposure induces allergic airway inflammation in sensitized subjects. The role of antigenic pollen proteins in the induction of allergic airway inflammation is well characterized, but the contribution of other constituents in pollen grains to this process is unknown. Here we show that pollen grains and their extracts contain intrinsic NADPH oxidases. The pollen NADPH oxidases rapidly increased the levels of ROS in lung epithelium as well as the amount of oxidized glutathione (GSSG) and...

Boldogh, Istvan; Bacsi, Attila; Choudhury, Barun K.; Dharajiya, Nilesh; Alam, Rafeul; Hazra, Tapas K.; Mitra, Sankar; Goldblum, Randall M.; Sur, Sanjiv

2005-01-01

350

Inhibitory Effects of Enalaprilat on Rat Cardiac Fibroblast Proliferation via ROS/P38MAPK/TGF-?1 Signaling Pathway  

Directory of Open Access Journals (Sweden)

Full Text Available Enalaprilat (Ena., an angiotensin II (Ang II converting enzyme inhibitor (ACEI, can produce some therapeutic effects on hypertension, ventricular hypertrophy and myocardial remodeling in clinic, but its precise mechanism, especially its signaling pathways remain elusive. In this study, cardiac fibroblasts (CFb was isolated by the trypsin digestion method; a BrdU proliferation assay was adopted to determine cell proliferation; an immunofluorescence assay was used to measure intracellular reactive oxygen species (ROS; immunocytochemistry staining and Western blotting assay were used to detect phosphorylated p38 mitogen activated protein kinase (p-p38MAPK and transforming growth factor-?1 (TGF-?1 protein expression, respectively. The results showed that Ang II (10–7 M stimulated the cardiac fibroblast proliferation which was inhibited by NAC (an antioxidant, SB203580 (a p38MAPK inhibitor or enalaprilat; Ang II caused an burst of intracellular ROS level within thirty minutes, an increase in p-p38MAPK (3.6-fold of that in the control group, as well as an elevation of TGF-?1 meantime; NAC, an antioxidant, and enalaprilat treatment attenuated cardiac fibroblast proliferation induced by Ang II and decreased ROS and p-p38MAPK protein levels in rat cardiac fibroblast; SB203580 lowered TGF-?1 protein expression in rats’ CFb in a dose-dependent manner. It could be concluded that enalaprilat can inhibit the cardiac fibroblast proliferation induced by Ang II via blocking ROS/P38MAPK/TGF-?1 signaling pathways and the study provides a theoretical proof for the application of ACEIs in treating myocardial fibrosis and discovering the primary mechanism through which ACEIs inhibit CFb proliferation.

Du-Juan Yu

2012-03-01

351

Inhibitory effects of enalaprilat on rat cardiac fibroblast proliferation via ROS/P38MAPK/TGF-?1 signaling pathway.  

Science.gov (United States)

Enalaprilat (Ena.), an angiotensin II (Ang II) converting enzyme inhibitor (ACEI), can produce some therapeutic effects on hypertension, ventricular hypertrophy and myocardial remodeling in clinic, but its precise mechanism, especially its signaling pathways remain elusive. In this study, cardiac fibroblasts (CFb) was isolated by the trypsin digestion method; a BrdU proliferation assay was adopted to determine cell proliferation; an immunofluorescence assay was used to measure intracellular reactive oxygen species (ROS); immunocytochemistry staining and Western blotting assay were used to detect phosphorylated p38 mitogen activated protein kinase (p-p38MAPK) and transforming growth factor-?(1) (TGF-?(1)) protein expression, respectively. The results showed that Ang II (10(-7) M) stimulated the cardiac fibroblast proliferation which was inhibited by NAC (an antioxidant), SB203580 (a p38MAPK inhibitor) or enalaprilat; Ang II caused an burst of intracellular ROS level within thirty minutes, an increase in p-p38MAPK (3.6-fold of that in the control group), as well as an elevation of TGF-?(1) meantime; NAC, an antioxidant, and enalaprilat treatment attenuated cardiac fibroblast proliferation induced by Ang II and decreased ROS and p-p38MAPK protein levels in rat cardiac fibroblast; SB203580 lowered TGF-?(1) protein expression in rats' CFb in a dose-dependent manner. It could be concluded that enalaprilat can inhibit the cardiac fibroblast proliferation induced by Ang II via blocking ROS/P38MAPK/TGF-?(1) signaling pathways and the study provides a theoretical proof for the application of ACEIs in treating myocardial fibrosis and discovering the primary mechanism through which ACEIs inhibit CFb proliferation. PMID:22395404

Yu, Min; Zheng, Yang; Sun, Hong-Xia; Yu, Du-Juan

2012-01-01

352

Plumbagin and juglone induce caspase-3-dependent apoptosis involving the mitochondria through ROS generation in human peripheral blood lymphocytes.  

Science.gov (United States)

The phytochemicals plumbagin and juglone have recently been gaining importance because of their various pharmacological activities. In this study, these compounds are shown to induce concentration- and time-dependent toxicity in human peripheral blood lymphocytes via the apoptotic pathway. Flow cytometry data revealed the occurrence of about 28% early apoptotic cells after 6h exposure to 10?M plumbagin and 35% late apoptotic cells and about 43% sub-G1 population after 24h. The cytotoxic effect of plumbagin was at least twofold higher than that of juglone as evidenced by the IC(50) value for cytotoxicity. Characteristic apoptotic features such as chromatin condensation and apoptotic body formation were observed through TEM, and membrane blebbing and cell surface smoothening were seen in SEM studies. Generation of ROS was evidenced through the HPLC analysis of superoxide-specific 2-OH-E+ formation. In addition, a decrease in GSH levels parallel to ROS production was observed. Reversal of apoptosis in both NAC- and Tempol-pretreated cells indicates the involvement of both ROS generation and GSH depletion in plumbagin- and juglone-induced apoptosis. The mechanistic pathway involves a decrease in MMP; alterations in the levels of Bcl-2, Bax, and cytosolic cytochrome c; and PARP-1 cleavage subsequent to caspase-3 activation. PMID:21982843

Seshadri, Priya; Rajaram, Anantanarayanan; Rajaram, Rama

2011-12-01

353

Reactive oxygen species (ROS) inducible DNA cross-linking agents and their effect on cancer cells and normal lymphocytes.  

Science.gov (United States)

Reducing host toxicity is one of the main challenges of cancer chemotherapy. Many tumor cells contain high levels of ROS that make them distinctively different from normal cells. We report a series of ROS-activated aromatic nitrogen mustards that selectively kill chronic lymphocytic leukemia (CLL) over normal lymphocytes. These agents showed powerful DNA cross-linking abilities when coupled with H2O2, one of the most common ROS in cancer cells, whereas little DNA cross-linking was detected without H2O2. Consistent with chemistry observation, in vitro cytotoxicity assay demonstrated that these agents induced 40-80% apoptosis in primary leukemic lymphocytes isolated from CLL patients but less than 25% cell death to normal lymphocytes from healthy donors. The IC50 for the most potent compound (2) was ~5 ?M in CLL cells, while the IC50 was not achieved in normal lymphocytes. Collectively, these data provide utility and selectivity of these agents that will inspire further and effective applications. PMID:24801734

Chen, Wenbing; Balakrishnan, Kumudha; Kuang, Yunyan; Han, Yanyan; Fu, Min; Gandhi, Varsha; Peng, Xiaohua

2014-06-12

354

UV light induces premature senescence in Akt1-null mouse embryonic fibroblasts by increasing intracellular levels of ROS  

Energy Technology Data Exchange (ETDEWEB)

Akt/PKB plays a pivotal role in cell survival and proliferation. Previously, we reported that UV-irradiation induces extensive cell death in Akt2{sup -/-} mouse embryonic fibroblasts (MEFs) while Akt1{sup -/-} MEFs show cell cycle arrest. Here, we find that Akt1{sup -/-} MEFs exhibit phenotypic changes characteristics of senescence upon UV-irradiation. An enlarged and flattened morphology, a reduced cell proliferation and an increased senescence-associated {beta}-galactosidase (SA {beta}-gal) staining indicate that Akt1{sup -/-} MEFs undergo premature senescence after UV-irradiation. Restoring Akt1 expression in Akt1{sup -/-} MEFs suppressed SA {beta}-gal activity, indicating that UV-induced senescence is due to the absence of Akt1 function. Notably, levels of ROS were rapidly increased upon UV-irradiation and the ROS scavenger NAC inhibits UV-induced senescence of Akt1{sup -/-} MEFs, suggesting that UV light induces premature senescence in Akt1{sup -/-} MEFs by modulating intracellular levels of ROS. In conjunction with our previous work, this indicates that different isoforms of Akt have distinct function in response to UV-irradiation.

Jee, Hye Jin; Kim, Hyun-Ju; Kim, Ae Jeong; Bae, Yoe-Sik [Department of Biochemistry, College of Medicine, Dong-A University, Busan (Korea, Republic of); Bae, Sun Sik [Department of Pharmacology, College of Medicine, Pusan National University, Busan (Korea, Republic of); Yun, Jeanho, E-mail: yunj@dau.ac.kr [Department of Biochemistry, College of Medicine, Dong-A University, Busan (Korea, Republic of)

2009-06-05

355

Autoxidation of Gallic acid Induces ROS-dependant Death in Human Prostate Cancer LNCaP Cells  

Science.gov (United States)

Background Prostate cancer is the second most common cause of mortality. Gallic acid (GA) is a natural polyphenol, and we tested its in-vitro cytotoxicity after 24 h in prostate cancer LNCaP cells. Materials and Methods GA autoxidation was measured fluorimetrically for H2O2, and O2·? radicals by chemiluminescence. Intracellular reactive oxygen species (ROS) levels were detected with 2’,7’-dichlorodihydrofluorescein diacetate. Cytotoxicity was evaluated by crystal-violet, while apoptosis and mitochondrial membrane potential were determined by flow cytometry. Cytochrome c release was detected by enzyme-linked immunosorbent assay, and caspase-8, -9 and -3 activities were measured calorimetrically. Results GA autoxidation produced significant levels of H2O2 and O2·?. Increased intracellular ROS levels with GA were reduced by N-acetyl-L-cysteine (NAC) and L-glutathione (GSH). Cells were protected against GA cytotoxicity when pretreated with increasing levels of superoxide dismutase/catalase mixture, NAC, or GSH for 3 h. The number of apoptotic cells increased with GA dose. GA caused mitochondrial potential loss, cytochrome c release, and activation of caspases 3, 8 and 9. Conclusion The results indicate that ROS-dependent apoptotic mechanism of GA kills malignant cells effectively; it is likely that GA could be a good anticancer agent. PMID:22593437

Russell, Larry H.; Mazzio, Elizabeth; Badisa, Ramesh B.; Zhu, Zhi-Ping; Agharahimi, Maryam; Oriaku, Ebenezer T.; Goodman, Carl B.

2012-01-01

356

Enhanced ROS production and oxidative damage in subcutaneous white adipose tissue mitochondria in obese and type 2 diabetes subjects.  

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Oxidative stress in the insulin target tissues has been implicated in the pathophysiology of type 2 diabetes. The study has examined the oxidative stress parameters in the mitochondria of subcutaneous white adipose tissue from obese and non-obese subjects with or without type 2 diabetes. An accumulation of protein carbonyls, fluorescent lipid peroxidation products, and malondialdehyde occurs in the adipose tissue mitochondria of obese type 2 diabetic, non-diabetic obese, and non-obese diabetic subjects with the maximum increase noticed in the obese type 2 diabetes patients and the minimum in non-obese type 2 diabetics. The mitochondria from obese type 2 diabetics, non-diabetic obese, and non-obese type 2 diabetics also produce significantly more reactive oxygen species (ROS) in vitro compared to those of controls, and apparently the mitochondrial ROS production rate in each group is proportional to the respective load of oxidative damage markers. Likewise, the mitochondrial antioxidant enzymes like superoxide dismutase and glutathione peroxidase show decreased activities most markedly in obese type 2 diabetes subjects and to a lesser degree in non-obese type 2 diabetes or non-diabetic obese subjects in comparison to control. The results imply that mitochondrial dysfunction with enhanced ROS production may contribute to the metabolic abnormality of adipose tissue in obesity and diabetes. PMID:25312902

Chattopadhyay, Mrittika; Khemka, Vineet Kumar; Chatterjee, Gargi; Ganguly, Anirban; Mukhopadhyay, Satinath; Chakrabarti, Sasanka

2015-01-01

357

Effect of freezing desiccation on cold hardiness, ROS, membrane lipid levels and antioxidant status in spruce seedlings  

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Full Text Available The symptoms of oxidative stress and antioxidative response were investigated on Norway spruce seedlings subjected to freezing desiccation conditions. Three-year-old seedlings were exposed to freezing desiccation at -3oC and -10oC for 45 days in two acclimation stages: autumn (October and winter (January. The stress enhanced the production of reactive oxygen species (ROS: superoxide radical anion (O2.-, and hydrogen peroxide (H2O2. Concentrations of low molecular antioxidants: glutathione (GSH, ascorbic acid (AsA and a-tocopherol declined at both low temperatures and acclimation stages. The activity of superoxide dismutase (SOD increased with ROS production, while guaiacol peroxidase (POX activity decreased. The freeze-induced desiccation of needles was significantly correlated with the cold hardiness (LT50, the level of low-molecular antioxidants, and POX activity, but not with SOD activity. Under extreme freezing desiccation conditions, these reactions continued, leading to the degradation of membrane phospholipids and a strong decrease in cold hardiness. The results show that membranes are the primary site of injury induced by ROS, produced under the influence of low temperature combined with dehydration. The acclimation response of Norway spruce needles to the oxidative stress generated by long-term cold and/or freezing desiccation is discussed.

Pawe? M. Pukacki

2005-09-01

358

Mediated homogenization  

International Nuclear Information System (INIS)

Homogenization protocols model the quantum mechanical evolution of a system to a fixed state independently from its initial configuration by repeatedly coupling it with a collection of identical ancillas. Here we analyze these protocols within the formalism of ''relaxing'' channels providing an easy-to-check sufficient condition for homogenization. In this context we describe mediated homogenization schemes where a network of connected qudits relaxes to a fixed state by only partially interacting with a bath. We also study configurations which allow us to introduce entanglement among the elements of the network. Finally we analyze the effect of having competitive configurations with two different baths and we prove the convergence to dynamical equilibrium for Heisenberg chains

359

Chlorella Induces Stomatal Closure via NADPH Oxidase-Dependent ROS Production and Its Effects on Instantaneous Water Use Efficiency in Vicia faba  

OpenAIRE

Reactive oxygen species (ROS) have been established to participate in stomatal closure induced by live microbes and microbe-associated molecular patterns (MAMPs). Chlorella as a beneficial microorganism can be expected to trigger stomatal closure via ROS production. Here, we reported that Chlorella induced stomatal closure in a dose-and time-dependent manner in epidermal peels of Vicia faba. Using pharmacological methods in this work, we found that the Chlorella-induced stomatal closure was a...

Li, Yan; Xu, Shan-shan; Gao, Jing; Pan, Sha; Wang, Gen-xuan

2014-01-01

360

Inhibition of ROS production through mitochondria-targeted antioxidant and mitochondrial uncoupling increases post-thaw sperm viability in yellow catfish.  

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Reactive oxygen species (ROS) are one of the main causes for decreased viability in cryopreserved sperm. Many studies have reported the beneficial effect of antioxidant supplements in freezing media for post-thaw sperm quality. In the present study, we explored two new approaches of ROS inhibition in sperm cryopreservation of yellow catfish, namely mitochondrial-targeted antioxidant and metabolic modulator targeting mitochondrial uncoupling pathways. Our study revealed that addition of MitoQ, a compound designed to deliver ubiquinone into mitochondria, significantly decreased ROS production, as well as lipid peroxidation, and increased post-thaw viability. Similarly, sperm incubated with 2,4-dinitrophenol (DNP), a chemical protonophore that induces mitochondrial uncoupling, also had reduced ROS production, as well as lipid peroxidation, and increased post-thaw sperm viability. Conversely, activation of uncoupling protein (UCP2) by 4-hydroxynonenal (HNE) neither reduced ROS production nor increased post-thaw sperm viability. Our findings indicate that ROS inhibition through mitochondrial-targeted antioxidant or mild mitochondrial uncoupling is beneficial for sperm cryopreservation in yellow catfish. Our study provides novel methods to mitigate oxidative stress induced damage in cryopreserved sperm for future applications. PMID:25260932

Fang, Lu; Bai, Chenglian; Chen, Yuanhong; Dai, Jun; Xiang, Yang; Ji, Xiaoping; Huang, Changjiang; Dong, Qiaoxiang

2014-12-01

361

Detection and comparison of reactive oxygen species (ROS) generated by chlorophyllin metal (Fe, Mg and Cu) complexes under ultrasonic and visible-light irradiation.  

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In this paper, in order to examine the mechanisms of sonodynamic and photodynamic reactions, the chlorophyllin metal (Chl-M (M=Fe, Mg and Cu)) complexes were irradiated by ultrasound (US) and visible-light (VL), respectively, and the generation of reactive oxygen species (ROS) were detected by the method of Oxidation-Extraction Spectrometry (OES). That is, the 1,5-diphenyl carbazide (DPCI) is oxidized by the generated ROS into 1,5-diphenyl carbazone (DPCO), which can display a various visible absorption around 563 nm wavelength. Besides, some influence parameters on the generation of ROS were also reviewed. The results demonstrated an apparent synergistic effect of Chl-M and ultrasonic or visible-light irradiation for the generation of ROS. Moreover, the quantities of generated ROS increase with the increase of (ultrasonic or visible-light) irradiation time and Chl-M (M=Fe, Mg and Cu) concentration. Finally, several quenchers were used to determine the kind of the generated ROS. It is wished that this paper might offer some valuable references for the study on the sonodynamic therapy (SDT) and photodynamic therapy (PDT) mechanisms and the application of Chl-M in tumor treatment. PMID:21236719

Wang, Jun; Guo, Yuwei; Gao, Jingqun; Jin, Xudong; Wang, Zhiqiu; Wang, Baoxin; Li, Kai; Li, Ying

2011-09-01

362

Unfolded protein response (UPR) signaling regulates arsenic trioxide-mediated macrophage innate immune function disruption  

Energy Technology Data Exchange (ETDEWEB)

Arsenic exposure is known to disrupt innate immune functions in humans and in experimental animals. In this study, we provide a mechanism by which arsenic trioxide (ATO) disrupts macrophage functions. ATO treatment of murine macrophage cells diminished internalization of FITC-labeled latex beads, impaired clearance of phagocytosed fluorescent bacteria and reduced secretion of pro-inflammatory cytokines. These impairments in macrophage functions are associated with ATO-induced unfolded protein response (UPR) signaling pathway characterized by the enhancement in proteins such as GRP78, p-PERK, p-eIF2?, ATF4 and CHOP. The expression of these proteins is altered both at transcriptional and translational levels. Pretreatment with chemical chaperon, 4-phenylbutyric acid (PBA) attenuated the ATO-induced activation in UPR signaling and afforded protection against ATO-induced disruption of macrophage functions. This treatment also reduced ATO-mediated reactive oxygen species (ROS) generation. Interestingly, treatment with antioxidant N-acetylcysteine (NAC) prior to ATO exposure, not only reduced ROS production and UPR signaling but also improved macrophage functions. These data demonstrate that UPR signaling and ROS generation are interdependent and are involved in the arsenic-induced pathobiology of macrophage. These data also provide a novel strategy to block the ATO-dependent impairment in innate immune responses. - Highlights: • Inorganic arsenic to humans and experimental animals disrupt innate immune responses. • The mechanism underlying arsenic impaired macrophage functions involves UPR signaling. • Chemical chaperon attenuates arsenic-mediated macrophage function impairment. • Antioxidant, NAC blocks impairment in arsenic-treated macrophage functions.

Srivastava, Ritesh K.; Li, Changzhao; Chaudhary, Sandeep C. [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, AL (United States); Ballestas, Mary E. [Department of Pediatrics Infectious Disease, Children' s of Alabama, School of Medicine, University of Alabama at Birmingham, AL (United States); Elmets, Craig A. [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, AL (United States); Robbins, David J. [Department of Surgery, Molecular Oncology Program, Miller School of Medicine, University of Miami, Miami (United States); Matalon, Sadis [Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, AL (United States); Deshane, Jessy S. [Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, AL (United States); Afaq, Farrukh [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, AL (United States); Bickers, David R. [Department of Dermatology, Columbia University Medical Center, New York (United States); Athar, Mohammad, E-mail: mathar@uab.edu [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, AL (United States)

2013-11-01

363

Does Nrf2 contribute to p53-mediated control of cell survival and death?  

Science.gov (United States)

In response to oxidative stress, the transcription factor Nrf2 is upregulated and controls activation of many genes that work in concert to defend cells from damages and to maintain cellular redox homeostasis. p53 has been regarded as the guardian of the genome through its pro-oxidant and antioxidant functions. Under low levels of reactive oxygen species (ROS), "normal" amounts of p53 upregulates expression of antioxidant genes, protecting macromolecules from ROS-induced damage. However, at high levels or extended exposure of ROS, p53 expression is enhanced, activating pro-oxidant genes and resulting in p53-dependent apoptosis. We observed a two-phase Nrf2 expression controlled by p53. (i) The induction phase: when p53 expression is relatively low, p53 enhances the protein level of Nrf2 and its target genes to promote cell survival in a p21-dependent manner. (ii) The repression phase: when p53 expression is high, the Nrf2-mediated survival response is inhibited by p53. Our observation leads to the hypothesis that the p53-mediated biphasic regulation of Nrf2 may be key for the tumor-suppressor function of p53 by coordinating cell survival and death pathways. PMID:22559194

Chen, Weimin; Jiang, Tao; Wang, Huihui; Tao, Shasha; Lau, Alexandria; Fang, Deyu; Zhang, Donna D

2012-12-15

364

Reactive oxygen species-mediated apoptosis contributes to chemosensitization effect of saikosaponins on cisplatin-induced cytotoxicity in cancer cells  

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Full Text Available Abstract Background Saikosaponin-a and -d, two naturally occurring compounds derived from Bupleurum radix, have been shown to exert anti-cancer activity in several cancer cell lines. However, the effect of combination of saikosaponins with chemotherapeutic drugs has never been addressed. Thus, we investigated whether these two saikosaponins have chemosensitization effect on cisplatin-induced cancer cell cytotoxicity. Methods Two cervical cancer cell lines, HeLa and Siha, an ovarian cancer cell line, SKOV3, and a non-small cell lung cancer cell line, A549, were treated with saikosaponins or cisplatin individually or in combination. Cell death was quantitatively detected by the release of lactate dehydrogenase (LDH using a cytotoxicity detection kit. Cellular ROS was analyzed by flow cytometry. Apoptosis was evaluated by AO/EB staining, flow cytometry after Anexin V and PI staining, and Western blot for caspase activation. ROS scavengers and caspase inhibitor were used to determine the roles of ROS and apoptosis in the effects of saikosaponins on cisplatin-induced cell death. Results Both saikosaponin-a and -d sensitized cancer cells to cisplatin-induced cell death in a dose-dependent manner, which was accompanied with induction of reactive oxygen species (ROS accumulation. The dead cells showed typical apoptotic morphologies. Both early apoptotic and late apoptotic cells detected by flow cytometry were increased in saikosaponins and cisplatin cotreated cells, accompanied by activation of the caspase pathway. The pan-caspase inhibitor z-VAD and ROS scanvengers butylated hydroxyanisole (BHA and N-acetyl-L-cysteine (NAC dramatically suppressed the potentiated cytotoxicity achieved by combination of saikosaponin-a or -d and cisplatin. Conclusions These results suggest that saikosaponins sensitize cancer cells to cisplatin through ROS-mediated apoptosis, and the combination of saikosaponins with cisplatin could be an effective therapeutic strategy.

He Fan

2010-12-01

365

Isoorientin induces apoptosis and autophagy simultaneously by reactive oxygen species (ROS)-related p53, PI3K/Akt, JNK, and p38 signaling pathways in HepG2 cancer cells.  

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Cell death is closely related to autophagy under some circumstances; however, the effect of isoorientin (ISO) on autophagy and the interplay between apoptosis and autophagy in human hepatoblastoma cancer (HepG2) cells remains poorly understood. The present study showed that ISO induced autophagy, which was correlated with the formation of autophagic vacuoles and the overexpression of Beclin-1 and LC3-II. The autophagy inhibitor 3-methyladenine (3-MA) markedly inhibited apoptosis, and the apoptosis inhibitor ZVAD-fmk also decreased ISO-induced autophagy. In addition, the PI3K/Akt inhibitor LY294002 enhanced Beclin-1, LC3-II, and poly(ADP-ribose) polymerase (PARP) cleavage levels. Also, the reactive oxygen species (ROS) inhibitor N-acetyl-L-cysteine (NAC), the JNK inhibitor SP600125, and the p38 inhibitor SB203580 efficiently downregulated the levels of these proteins. Moreover, the p53 inhibitor pifithrin-? and the nuclear factor (NF)-?B inhibitor pyrrolidinedithiocarbamic acid (PDTC) clearly suppressed Beclin-1 and LC3-II and increased cytochrome c release, caspase-3 activation, and PARP cleavage. These results demonstrated for the first time that ISO simultaneously induced apoptosis and autophagy by ROS-related p53, PI3K/Akt, JNK, and p38 signaling pathways. Furthermore, ISO-induced apoptosis by activating the Fas receptor-mediated apoptotic pathway and suppressing the p53 and PI3K/Akt-dependent NF-?B signaling pathway, with the subsequent increase in the release of cytochrome c, caspase-3 activation, and PARP cleavage. PMID:24841907

Yuan, Li; Wei, Shuping; Wang, Jing; Liu, Xuebo

2014-06-11

366

Atmospheric pressure gas plasma-induced colorectal cancer cell death is mediated by Nox2-ASK1 apoptosis pathways and oxidative stress is mitigated by Srx-Nrf2 anti-oxidant system.  

Science.gov (United States)

Atmospheric pressure gas plasma (AGP) generates reactive oxygen species (ROS) that induce apoptosis in cultured cancer cells. The majority of cancer cells develop a ROS-scavenging anti-oxidant system regulated by Nrf2, which confers resistance to ROS-mediated cancer cell death. Generation of ROS is involved in the AGP-induced cancer cell death of several colorectal cancer cells (Caco2, HCT116 and SW480) by activation of ASK1-mediated apoptosis signaling pathway without affecting control cells (human colonic sub-epithelial myofibroblasts; CO18, human fetal lung fibroblast; MRC5 and fetal human colon; FHC). However, the identity of an oxidase participating in AGP-induced cancer cell death is unknown. Here, we report that AGP up-regulates the expression of Nox2 (NADPH oxidase) to produce ROS. RNA interference designed to target Nox2 effectively inhibits the AGP-induced ROS production and cancer cell death. In some cases both colorectal cancer HT29 and control cells showed resistance to AGP treatment. Compared to AGP-sensitive Caco2 cells, HT29 cells show a higher basal level of the anti-oxidant system transcriptional regulator Nrf2 and its target protein sulfiredoxin (Srx) which are involved in cellular redox homeostasis. Silencing of both Nrf2 and Srx sensitized HT29 cells, leads to ROS overproduction and decreased cell viability. This indicates that in HT29 cells, Nrf2/Srx axis is a protective factor against AGP-induced oxidative stress. The inhibition of Nrf2/Srx signaling should be considered as a central target in drug-resistant colorectal cancer treatments. PMID:25173814

Ishaq, Musarat; Evans, Margaret D M; Ostrikov, Kostya Ken

2014-12-01

367

Peptide blockers of PKG inhibit ROS generation by acetylcholine and bradykinin in cardiomyocytes but fail to block protection in the whole heart.  

Science.gov (United States)

Bradykinin and acetylcholine (ACh) trigger preconditioning by ATP-sensitive K(+) (K(ATP)) channel-dependent production of reactive oxygen species (ROS). Recent evidence suggests that ROS production may in turn be influenced by cGMP-dependent protein kinase (PKG). This study utilized DT-2 and DT-3 peptides, highly specific membrane-permeable blockers of PKG. Rabbit cardiomyocytes were incubated for 15 min in reduced MitoTracker red, which becomes fluorescent only after exposure to ROS. Bradykinin (400 nM) and ACh (250 microM) caused a 49.9 +/- 5.9% and 46.8 +/- 1.7% increase in ROS production, respectively (P < 0.005 vs. untreated cells). Coincubation with DT-3 (250 nM) abolished both the ACh- and bradykinin-induced ROS signal, whereas a nonpermeable form of the peptide (W45) had no effect on ACh-induced ROS production. DT-3 was unable to block ROS production from diazoxide (100 microM), a selective opener of mitochondrial K(ATP) channels, suggesting that these channels are downstream of PKG. DT-2 (125 nM) also prevented ACh from triggering ROS production. 8-(4-Chlorophenylthio)-guanosine 3',5'-cyclic monophosphate (100 microM), a cGMP analog and potent direct activator of PKG, increased ROS production of cardiomyocytes by 44.7 +/- 7.1% (P < 0.001 vs. untreated cells). This increase was blocked by DT-2. Neither DT-2 nor DT-3 could block the anti-infarct effect of bradykinin in isolated rabbit hearts. Studies with fluorescent-tagged DT-3 revealed that it was confined to endothelial cells and never reached the myocytes. We conclude that both bradykinin and ACh trigger ROS generation by a pathway that includes PKG. Although the peptides may be inappropriate for a whole heart model, they are likely to become important tool drugs for elucidation of signal transduction pathways in cell preparations. PMID:15591097

Krieg, Thomas; Philipp, Sebastian; Cui, Lin; Dostmann, Wolfgang R; Downey, James M; Cohen, Michael V

2005-04-01

368

Comparison of ROS formation and antioxidant enzymes in Cleome gynandra (C?) and Cleome spinosa (C?) under drought stress.  

Science.gov (United States)

Differences between antioxidant responses to drought in C(3) and C(4) plants are rather scanty. Even, we are not aware of any research on comparative ROS formation and antioxidant enzymes in C(3) and C(4) species differing in carboxylation pathway of same genus which would be useful to prevent other differences in plant metabolism. With this aim, relative shoot growth rate, relative water content and osmotic potential, hydrogen peroxide (H(2)O(2)) content and NADPH oxidase (NOX) activity, antioxidant defence system (superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), ascorbate peroxidase (APX), glutathione reductase (GR) enzymes and their isoenzymes), CAT1 mRNA level, and lipid peroxidation in seedlings of Cleome spinosa (C(3)) and Cleome gynandra (C(4)) species of Cleome genus exposed to drought stress for 5 and 10 day (d) were comparatively investigated. Constitutive levels of antioxidant enzymes (except SOD) were consistently higher in C. spinosa than in C. gynandra under control conditions. CAT1 gene expression in C. spinosa was correlated with CAT activity but CAT1 gene expression in C. gynandra at 10 d did not show this correlation. Drought stress caused an increase in POX, CAT, APX and GR in both species. However, SOD activity was slightly decreased in C. gynandra while it was remained unchanged or increased on 5 and 10 d of stress in C. spinosa, respectively. Parallel to results of malon dialdehyde (MDA), H(2)O(2) content was also remarkably increased in C. spinosa as compared to C. gynandra under drought stress. These results suggest that in C. spinosa, antioxidant defence system was insufficient to suppress the increasing ROS production under stress condition. On the other hand, in C. gynandra, although its induction was lower as compared to C. spinosa, antioxidant system was able to cope with ROS formation under drought stress. PMID:22118616

Uzilday, B; Turkan, I; Sekmen, A H; Ozgur, R; Karakaya, H C

2012-01-01

369

Red photon treatment inhibits apoptosis via regulation of bcl-2 proteins and ROS levels, alleviating hypoxic-ischemic brain damage.  

Science.gov (United States)

Therapeutic options for hypoxic-ischemic brain damage (HIBD) are scarce and inefficient. Recently, many studies have demonstrated that red photon plays an important role in anti-inflammatory processes as well as apoptosis, the main trait of HIBD. In this study, we investigated whether red photon can protect from HIBD in SD rats and oxygen-glucose deprivation (OGD) in PC12 cells. Apoptosis, mitochondrial transmembrane potential (MMP), and reactive oxygen species (ROS) rates were assessed in PC12 cells. We found that 6-h irradiation resulted in decreased MMP, ROS and apoptosis rates, although these changes were reversible with prolonged irradiation. Importantly, these effects were sustained for 2-8h upon quenching of the red photon. Similar trends were observed for protein and mRNA expression of bax and bcl-2, with short-term irradiation (6h) inhibiting apoptosis in PC12 Cells. However, long-term (>6h) irradiation caused cell damage. In vivo experiments, bax mRNA and protein levels were reduced after 7days in HIBD model rats treated with red photon, in contrast to bcl-2. Furthermore, we found that bax and bcl-2 were mainly expressed in pyramidal cells of the hippocampus CA1 and CA3. Importantly, Morris Water Maze test results revealed an improvement in learning ability and spatial memory in rats after irradiation. Overall, our data showed that short-term irradiation with red photon in the acute phase inhibits the mitochondrial apoptotic pathway via regulation of bcl-2-related proteins and reduction of ROS levels, thereby decreasing apoptosis in nerve cells and improving the neurological prognosis of HIBD. PMID:24607343

Jiang, W; Chen, L; Zhang, X J; Chen, J; Li, X C; Hou, W S; Xiao, N

2014-05-30

370

Reactive oxygen and nitrogen (ROS and RNS) species generation and cell death in tomato suspension cultures--Botrytis cinerea interaction.  

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This article reports events connected to cell survival and Botrytis cinerea infection development in cell suspension cultures of two tomato cultivars which show different levels of susceptibility to the pathogen: cv. Corindo (more susceptible) and cv. Perkoz (less susceptible). In parallel changes in reactive oxygen (ROS) and nitrogen (RNS) species generation and in S-nitrosoglutathione reductase (GSNOR) activity were studied. In vivo staining methods with acridine orange (AO) and ethidium bromide (EB) as well as fluorescent microscopy were used to assess tomato and B. cinerea cells death. The biochemical studies of ROS and RNS concentrations in plant cell extract were complemented by in vivo ROS and nitric oxide (NO) imaging using nitro blue tetrazolium (NBT), diaminobenzidine (DAB) and diaminofluorescein diacetate (DAF-DA) staining methods, and confocal microscope technique. B. cinerea infection proceeded slower in Perkoz cell cultures. It was evidenced by measuring the pathogen conidia germination and germination tube development in which nuclei revealing cell death dominated. Two different types of tomato cell death were observed: cells with necrotic nuclei dominated in Corindo whereas in Perkoz cells with characteristic of vacuolar death type prevailed. In Perkoz cells, constitutive levels of NO and S-nitrosothiols (SNO) were significantly higher and hydrogen peroxide (H?O?) and superoxide anion (O?(-)) concentrations were slightly higher as compared with Corindo cells. Moreover, increases in these molecule concentrations as a result of B. cinerea inoculation were observed in both, Perkoz and Corindo cell cultures. The enzymatic GSNOR activity seems to be an important player in controlling the SNO level in tomato cells. Involvements of the studied compounds in molecular mechanisms of tomato resistance to B. cinerea are discussed in the paper. PMID:25064634

Pietrowska, E; Ró?alska, S; Ka?mierczak, A; Nawrocka, J; Ma?olepsza, U

2015-01-01

371

Highly diluted compounds effects on B16-F10 melanogenesis, reactive oxygen species (ROS production and tumorigenesis.  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Cutaneous melanoma is a highly malignant tumor derived from pigment-producing (melanin melanocytes of skin epidermis. Cutaneous pigmentation is described as the major physiologic defense against UV radiation. During melanin biosynthesis and other tumorigenic process, reactive oxygen species (ROS are produced and might be critically involved in several melanomagenesis stages. ROS play key roles on regulation of many types cell proliferation, including melanoma cells. Aims: In this work we evaluated the effects of highly diluted compounds on melanogenesis and changes in reactive oxygen species after 96 hours of treatment and possible involvement in tumorigenesis. Methodology: Melanin content was measured in B16-F10 cells after 96 hours of treatment with highly diluted compounds, as well as the superoxide anion, hydrogen peroxide and nitric oxide. Furthermore, the effects of highly diluted compounds on cell proliferation were investigated by trypan blue exclusion method after 48 hours of treatment. Results: Treatment led to an increase in B16-F10 melanin content and a decrease in nitrite concentration, an intermediate product of nitric oxide. We also observed a decrease in cell proliferation after treatment. It is well recognized that nitric oxide (NO is involved in tumor progression, including melanoma. Several articles show that NO treated B16-F10 cells exhibited higher metastatic capacity. Thereby, reduction in cell proliferation can be due to low NO levels. It is speculated that melanocytes are programmed to survive in order to preserve their photoprotective role, thus in a compensatory manner the cell may be synthesizing melanin in response to cell proliferation reduction. Conclusions: These results suggest that treatment may be reducing tumorigenic capacity via ROS reduction. However further studies are need to better understand highly diluted compounds mechanisms of action.

Edvaldo da Silva Trindade

2012-09-01

372

Salt-induced stabilization of EIN3/EIL1 confers salinity tolerance by deterring ROS accumulation in Arabidopsis.  

Science.gov (United States)

Ethylene has been regarded as a stress hormone to regulate myriad stress responses. Salinity stress is one of the most serious abiotic stresses limiting plant growth and development. But how ethylene signaling is involved in plant response to salt stress is poorly understood. Here we showed that Arabidopsis plants pretreated with ethylene exhibited enhanced tolerance to salt stress. Gain- and loss-of-function studies demonstrated that EIN3 (ETHYLENE INSENSITIVE 3) and EIL1 (EIN3-LIKE 1), two ethylene-activated transcription factors, are necessary and sufficient for the enhanced salt tolerance. High salinity induced the accumulation of EIN3/EIL1 proteins by promoting the proteasomal degradation of two EIN3/EIL1-targeting F-box proteins, EBF1 and EBF2, in an EIN2-independent manner. Whole-genome transcriptome analysis identified a list of SIED (Salt-Induced and EIN3/EIL1-Dependent) genes that participate in salt stress responses, including several genes encoding reactive oxygen species (ROS) scavengers. We performed a genetic screen for ein3 eil1-like salt-hypersensitive mutants and identified 5 EIN3 direct target genes including a previously unknown gene, SIED1 (At5g22270), which encodes a 93-amino acid polypeptide involved in ROS dismissal. We also found that activation of EIN3 increased peroxidase (POD) activity through the direct transcriptional regulation of PODs expression. Accordingly, ethylene pretreatment or EIN3 activation was able to preclude excess ROS accumulation and increased tolerance to salt stress. Taken together, our study provides new insights into the molecular action of ethylene signaling to enhance plant salt tolerance, and elucidates the transcriptional network of EIN3 in salt stress response. PMID:25330213

Peng, Jinying; Li, Zhonghai; Wen, Xing; Li, Wenyang; Shi, Hui; Yang, Longshu; Zhu, Huaiqiu; Guo, Hongwei

2014-10-01

373

Responses to ROS inducer agents in zebrafish cell line: differences between copper and UV-B radiation.  

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Fish are commonly exposed to environmental pollutants, which in turns could induce an oxidative stress. So, it is important to understand the effects and the responses elicited by these toxicants in fish species, being fish cell lines important tools for this purpose. Thus, the aim of the present study was to compare the effects of copper and UV-B radiation exposure on zebrafish hepatocytes (ZFL lineage) in terms of reactive oxygen species (ROS) levels, sulfhydril groups content and mRNA levels of important genes related to cellular response to toxic agents. Exposure of ZFL cells to UV-B radiation (23.3 mJ/cm(2)) significantly increased levels of intracellular ROS and mRNA of both superoxide dismutase isoforms (sod1 and sod2), three glutathione S-transferase isoforms (gst?, gstµ and gst?) and a heat shock protein (hsp70). However, no changes in nonprotein sulfhydryl groups (NP-SH) content, as well as in the mRNA levels of genes related to glutathione (GSH) synthesis and recycling, were observed. Contrary to this, copper exposure (20 mg/L) diminished NP-SH content and increased the levels of mRNA of genes related to GSH synthesis (gclc and gs). Moreover, copper exposure increases the mRNA levels of some genes related to antioxidant defenses (gpx and gst?), biotransformation reactions (cyp1a1) and protein repair (hsp70). In conclusion, these results demonstrated that both toxicants could increase ROS levels in ZFL cell line, but the responses are different, which could be related to activation of different signaling pathways. PMID:25119852

Rola, Regina Coimbra; Marins, Luis Fernando; Nery, Luiz Eduardo Maia; da Rosa, Carlos Eduardo; Sandrini, Juliana Zomer

2014-12-01

374

Disulfiram Eradicates Tumor-Initiating Hepatocellular Carcinoma Cells in ROS-p38 MAPK Pathway-Dependent and -Independent Manners  

Science.gov (United States)

Tumor-initiating cells (TICs) play a central role in tumor development, metastasis, and recurrence. In the present study, we investigated the effect of disulfiram (DSF), an inhibitor of aldehyde dehydrogenase, toward tumor-initiating hepatocellular carcinoma (HCC) cells. DSF treatment suppressed the anchorage-independent sphere formation of both HCC cells. Flow cytometric analyses showed that DSF but not 5-fluorouracil (5-FU) drastically reduces the number of tumor-initiating HCC cells. The sphere formation assays of epithelial cell adhesion molecule (EpCAM)+ HCC cells co-treated with p38-specific inhibitor revealed that DSF suppresses self-renewal capability mainly through the activation of reactive oxygen species (ROS)-p38 MAPK pathway. Microarray experiments also revealed the enrichment of the gene set involved in p38 MAPK signaling in EpCAM+ cells treated with DSF but not 5-FU. In addition, DSF appeared to downregulate Glypican 3 (GPC3) in a manner independent of ROS-p38 MAPK pathway. GPC3 was co-expressed with EpCAM in HCC cell lines and primary HCC cells and GPC3-knockdown reduced the number of EpCAM+ cells by compromising their self-renewal capability and inducing the apoptosis. These results indicate that DSF impaired the tumorigenicity of tumor-initiating HCC cells through activation of ROS-p38 pathway and in part through the downregulation of GPC3. DSF might be a promising therapeutic agent for the eradication of tumor-initiating HCC cells. PMID:24454751

Yuki, Kaori; Zen, Yoh; Oshima, Motohiko; Miyagi, Satoru; Saraya, Atsunori; Koide, Shuhei; Motoyama, Tenyu; Ogasawara, Sadahisa; Ooka, Yoshihiko; Tawada, Akinobu; Nakatsura, Tetsuya; Hayashi, Takehiro; Yamashita, Taro; Kaneko, Syuichi; Miyazaki, Masaru; Iwama, Atsus